PTFE, FEP, and PFA Specifications

TECHNICAL DESCRIPTION

Because of its molecular structure, traditional PTFE cannot be processed by melting, but must be compressed into shapes and heated under pressure (sintered). In contrast, FEP and PFA are melt-processable by conventional thermoplastic processing methods, including injection, transfer, blow, and compression molding and by extrusion.

( see also Generic PTFE and Teflon® PTFE Specifications )

FEP DESCRIPTION

TetraFluorEthylene-Perfluorpropylene (FEP) is produced by copolymerization of tetrafluoroethylene and hexafluoropropylene. It is a relatively soft thermoplastic with lower tensile strength, wear resistance, and creep resistance than many other engineering plastics. However, it is chemically inert and has a low dielectric constant over a wide frequency range. FEP possesses a very high degree of stress crack resistance, a low coefficient of friction, exceptional dielectric properties, heat resistance, retention of properties after service at 400°F (204°C) with useful properties at -454°F (-270°C), and meets FDA 21CFR.177.1550.

FEP has high transparency (with good transmittance of UltraViolet and visible wavelengths.) It has long term weatherability and excellent resistance to ozone, sunlight and weather. FEP offers the lowest refractive index of all thermoplastics with low light reflection (the same as water.)

Important applications are linings for pipe and chemical processing equipment, roll covers, and numerous wire and cable applications, including aircraft wire, plenum cable, fire alarm cable, and well logging cable. Heat-shrinkable FEP tubing is available. FEP Film is used as glazing in solar energy collectors.

Common FEP tradenames include Daikin Neoflon ^®, Dupont Teflon ^®, and Hoechst Hostaflon ^®.

PFA DESCRIPTION
PerFluoroAlkoxy (PFA) offers similar properties to FEP, but is considered more of a premium resin. PFA is preferred when extended service is required in hostile environments involving chemical, thermal, and mechanical stress. PFA offers high melt strength, stability at high processing temperatures, excellent crack and stress resistance, a low coefficient of friction, and more than 10 times the Flex life of FEP.

It has high resistance to creep and retention of properties after service at 500°F (260°C), with useful properties at -320°F (95°C). PFA also meets FDA 21CFR.177.1550.

PFA is used in the same types of applications as those listed above for FEP.

Common PFA tradenames include Daikin Neoflon ^®, Dupont Teflon ^®, Hoechst Hostaflon ^®, and Ausimont Hyflon ^®.