Patent ID: 7709424

Claim:
A lubricating oil composition, which comprises a perfluoropolyether base oil, and a fluorine-containing polyether diphosphonic acid ester, represented by the following general formula: (R 2 O)(R 1 O)P(O)(CH 2 ) a CF(CF 3 )[OCF 2 CF(CF 3 )] b O(CF 2 ) c O[CF(CF 3 )CF 2 O] d CF(CF 3 )(CH 2 ) e P(O)(OR 3 )(OR 4 ) (where R 1 , R 2 , R 3 , and R 4 are hydrogen atoms, alkyl groups, cycloalkyl groups, aryl groups, alkylaryl groups, aralkyl groups, or any of the foregoing groups, some or whole of whose hydrogen atoms are substituted with halogen atoms, and subscripts a, b, c, d, and e are integers satisfying conditions of 2≦a+e≦8, b+d≦28, and 1≦c≦10, and subscripts b and d can be 0).