A bit of history…
The story of Teflon® began on April 6, 1938, at Du Pont's Jackson Laboratory in New Jersey, where Dr. Roy J. Plunkett was working with gases related to FREON* refrigerants, another Du Pont product. Upon checking a frozen, compressed sample of tetrafluoroethylene, he and his associates discovered that it had polymerised spontaneously to a white, waxy solid:poly-tetrafluoroethylene or PTFE.
Testing showed that PTFE was a remarkable material. It was resistant to almost every chemical and solvent, its surface was so slippery that virtually nothing would stick to it.
Moisture did not affect it, nor did it degrade after prolonged exposure to sunlight. In adai-tion it had an unusually high melting point and, unlike conventional thermoplastics, the resin would not flow above this melting point.
Borrowing from powder metallurgy, Du Pont engineers were able to convert Teflon® PTFE into blocks that could be machined into desired shapes. Subsequently aqueous dispersions of PTFE were developed and a special fine powder grade was invented that could be extruded as a lubricated paste and then sintered.
After the commercialisation of Teflon® PTFE in the 1940s, new opportunities for fluoropolymers soon developed. This led to the need for a fluoroplastic that would retain the unique and desirable properties of PTFE but which could be processed by normal thermoplastic conversion methods.
In 1960 Du Pont introduced Teflon® FEP ("fluorinated ethylene propyl-ene", i.e. a copolymer of tetrafluoroethylene and hexa-fluoropropylene), the first fully fluorinated polymer that could be melt-extruded and injection-moulded. Although some temperature resistance was sacrificed relative to PTFE, Teflon® FEP remained thermally much superior to most other plastics available at that time.
In 1970 Du Pont introduced TEFZEL® fluoropolymer, a modified copolymer of ethylene and tetrafluoroethylene
This polymer has high tensile strength and toughness, which makes it particularly suitable as a wire and cable insulation (rated at 155°C for 20 000 h. continuous exposure). It is now extensively used in electrical systems in aircraft, computers, telecommunications installations, heating circuits and other electrical applications.
In 1972 Du Pont introduced Teflon® PFA, a fluoro-plastic with excellent melt processibility and properties rivalling those of PTFE.
Teflon® PFA ("per-fluoroalkoxy", i.e. a copoly-mer of tetrafluoroethyfene and perfluorinated vinyl ether) offers high-temperature strength and stiffness, excellent stress-crack resistance and flex life.
It also has the general characteristics of Teflon® resins, such as resistance to virtually all chemicals, low coefficient of friction and excellent dielectric properties.
Teflon® is also available as a fibre for use in packing and filters in the chemicals industry. Teflon® finishes are also available and used for industrial and domestic anti-stick coatings.
Teflon® MP fluoro-additives and Teflon AF amorphous fluoropolymers are the latest additions to the family of fluoropolymers.
