Polytetrafluoroethylene (PTFE) is a fluorocarbon plastic; that is, a plastic in which the hydrogen normally found in association with carbon in organic materials has been replaced by fluorine. This produces a number of remarkable properties, and PTFE is reputedly the most inert substance known to man. It was discovered and developed by Dupont?, whose trade name is Teflon?. The outstanding properties of PTFE are:
Inertness: affected only by a number of uncommon substances at high temperature
Low friction: co-efficient 0.04 - 0.10, depending on load and surface speed
Outstanding electrical insulation and di-electric properties
Extreme heat and cold resistance: -190°C to + 260°C
High release from sticky materials ("non-stick")
Chemical, corrosion, and moisture resistance
Easy cleaning (nothing bonds permanently)
Mildew, and fungus resistance
Food contact approval
PTFE Fabric is best known generally as a non-stick lining in cooking utensils and on cutting tools, and as a thread seal tape. There are a vast number of industrial uses for which PTFE is available as block, sheet, rod and tube, all of which can be machined in similar fashion to metal. PTFE Coated Fabric can be formed by casting, extrusion or skiving (veneering) processes. .
There are a number of other fluorocarbons which have some degree of similarity to PTFE. The closest in performance properties, are commonly used for processing and coating:
Fluorinated Ethylene Propylene (FEP). Working temperature is -260°C to +205°C. As it forms a proper film surface (as opposed to the micro-porous sintered surface of PTFE) it has lower permeability to most liquids and gases (and resists the locking on of ice). Impact strength and wear resistance are also higher.
Perfluorinated Alkoxy (PFA), a co-polymer of PTFE. Working temperature is -260°C to +260°C. It has similar properties to FEP but with the higher working temperature of PTFE.
