Copolymers of tetrafluoroethyene oxide and hexafluoropropylene oxide useful as lubricants

Abstract

A copolymer includes 20 mol % to 80 mol % of —CF2CF2O— units, 20 mol % to 80 mol % of —CF(CF3)CF2O— units, and 0 mol % to 45 mol % of one or more additional perfluoroalkyleneoxy units. The copolymer has a molecular weight Mn of 1,500 to 20,000, a viscosity index of 100 to 220, and an average tetrafluoroethylene oxide (TFEO) run length less than 6. A process of forming a perfluoroalkyl polyether copolymer includes feeding a gas stream containing TFEO and hexafluoropropylene oxide (HFPO) into a reactor containing a fluorinated solvent, a fluoride salt, an ether, and an acid fluoride to form an acid fluoride-containing polymer. The process also includes hydrolyzing the acid fluoride-containing polymer to form a perfluoroalkyl polyether carboxylic acid or carboxylate salt. The process further includes distilling off the fluorinated solvent and treating the perfluoroalkyl polyether carboxylic acid or carboxylate salt with elemental fluorine to obtain the perfluoroalkyl polyether copolymer.

Dependencies are inferred from the claim text.