Perfluoroalkylpolyethers: A New Class of Synthetic Lubricants Available to Purchase

The physical and chemical properties of a new class of synthetic lubricants, the perfluoroalkylpolyether oils and the polytetrufluoroethylene‐thickened greases made from these oils, are described in some detail. The properties which make these products of interest as lubricants for use under severe conditions are shown to be I) excellent thermal and oxidative stability, 2) extreme inertness to many reactive chemicals, 3) broad liquid range and good viscosity‐temperature characteristics, 4) complete nonflammability, 5) good lubricating qualities, 6) compatibility with most elastomers and metals at suitable operating temperatures and 7) insolubility in most common solvents. The commercial process used in the production of these lubricants is described. The oils are disclosed to be fluorine end capped polymers of hexafluoropropylene epoxide having number average molecular weights of from 2000 to 7500, and the preferred thickener for the greases is disclosed to be a telomer of tetrafluoroethylene having a molecular weight of 20,000 to 30,000. A number of the commercial uses of these oils and greases, sold by Du Pont under the trade‐name Krytox®, are described including specific examples of instances where their performance far exceeded that of other available lubricants. Some uses in the space and aircraft industries are also discussed.