Page 209 - b.safe catalog

PTFE – Polytetrafluorethylene
Discovered in 1938 by research-chemists of the DuPont (USA) it was not intro- duced to the market until 1946. A partly crystalline fluoroplastic that belongs to the family of thermoplastics (but not suitable for injection moulding). The strong bond of the fluorine atom to the carbon atom as well as the almost complete shielding of the unbranched carbon chain by fluorine atoms result in a remarkably high chemical and thermal load.
PTFE has a thermal resistance ranging from -260 °C up to +250 °C, at short term up to +300 °C (e. g. no brittleness in boiling helium at -269 °C). This tem- perature range is not reached by any other plastic material.
The continuous operating temperature depends on the load. This means that PTFE can be used from -200 °C to +250 °C at moderate mechanical load. PTFE labware has a white appearance and a non-adhesive surface which is easy to clean. Furthermore, this material has excellent slip characteristics. A lubrica- tion of turning steel or glass shafts is not necessary. Semi-finished PTFE rods are fabricated by isostatic pressing processes or extrusion. The final products are produced by machining the semi-finished materials.
FEP – Tetrafluorethylene-Perfluoropropylene
A molten copolymer of tetrafluorethylene and perfluoropropylene with a high-molecular, partly crystalline structure which had been introduced on the market in 1960. Its mechanical and chemical properties are comparable with those of PTFE, however, the upper limit of the permanent working tempe- rature is 50 °C lower (max. +205 °C). FEP is a typical thermoplastic material, which can be processed with the known production methods for this kind of material. New types with lower melting viscosity (= high melt flow index MFR) allow the processing at higher speed. FEP labware is translucent to transpa- rent and non-porous.
PFA – Perfluoralkoxy Copolymer
Fluorinated hydrocarbon with a high-molecular, partly crystalline structure. Compared to PTFE, it has additional side chains consisting of perfluorated alkoxy groups.
PFA can be processed using thermoplastic production methods and offers chemical and thermal properties equal to those of PTFE. PFA labware is trans- lucent to transparent, non-porous and particularly useful in high-purity work. Big components with a total weight of several kilograms can be fabricated in a „single shot“ by using transfer moulding.
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b.safeTECHNICAL INFORMATION 177
Trade names
3MTM DyneonTM PTFE by Dyneon
Teflon® by Chemours Fluon® by AGC Chemicals Europe
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Trade names
Teflon® FEP by Chemours DyneonTM Fluorothermoplastics FEP by Dyneon
Neoflon® by Daikin
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Trade names
Teflon® PFA by Chemours DyneonTM Fluorothermoplastics PFA by Dyneon