Fluorinated ethylene propylene (FEP) is a copolymer of hexafluoropropylene and tetrafluoroethylene. It differs from the polytetrafluoroethylene (PTFE) resins in that it is melt-processable using conventional injection molding and screw extrusion techniques.
FEP is very similar in composition to the fluoropolymers PTFE and PFA. FEP and PFA both share PTFE’s useful properties of low friction and non-reactivity, but are more easily formable. FEP is softer than PTFE and melts at 260 °C; it is highly transparent and resistant to sunlight.
Like PTFE, FEP is mainly used for wiring, e.g. hookup wire, coaxial cable, wiring for computer wires and technical gear. An illustrative end product is for coaxial cables like RG-316. FEP film can be used to protect molds during the curing process. In such applications, the film is called “release film” and is intended to prevent the curing adhesive polymer from bonding to the metal tooling. Being able to maintain chemical composure in extreme temperatures and resist damage from chemical fuels further makes FEP a suitable choice in the industry. It is also used in UV cured resin 3D printing. Due to the aforementioned properties of high optical transparency and low friction, it is ideally suited for use on the bottom of the resin reservoir (opposite the build plate). This allows for the ultraviolet light to penetrate into the resin, then after the layer has hardened, the build plate can move away pulling the hardened resin away from the FEP film.
FEP is available in electrostatic coating powder, pellet, masterbatch and custom compound.