LUBRICANT COMPOSITIONS FOR VACUUM PUMPS

摘要

The invention pertains to a lubricant composition comprising: (A) at least one non-functional (per)fluoropolyether oil (PFPE oil) comprising at least one (per)fluoropolyoxyalkylene chain (chain RF); (B) at least one cyclic phosphazene compound [compound (P)] comprising one or more cyclic moieties having formula (I) or (II) here below: said cyclic moieties comprising, bound to one or more phosphorus atoms, at least one substituent comprising at least one (per)fluoropolyoxyalkylene chain (chain R' F); (C) at least one functional (per)fluoropolyether derivative (functional PFPE derivative) different from compound (P) comprising at least one (per)fluoropolyoxyalkylene chain (chain R'F) and at least one functional group comprising at least one monocyclic or polycyclic aromatic ring, said aromatic ring optionally containing one or more heteroatoms selected from N, O and S and one or more substituents different from hydrogen atoms.