Patent ID: 7361421

Claim:
A lubricant comprising at least one compound selected from fluorine-based diester dicarboxylic acid compounds represented by a formula (a), and at least one compound selected from fluorine-based diester compounds represented by a formula (b) and fluorine-based monoester compounds represented by a formula (c): wherein, R 1 , R 2 , R 3 and R 4 each represent hydrogen, an aliphatic alkyl group or an aliphatic alkenyl group, at least one of R 1 and R 2 is hydrogen, at least one of R 3 and R4 is hydrogen, “m” is an integer of 1 to 6, “n” is an integer of 1 to 5, “p” and “q” each are an integer of 0 to 30 and “r” is an integer of 1 to 12; wherein, R 5 and R 6 each represent an aliphatic alkyl group or an aliphatic alkenyl group, “x” is an integer of 1 to 6, “y” is an integer of 1 to 5, “s” and “t” each are an integer of 0 to 30 and “u” is an integer of 1 to 12; wherein, R 7 represents a fluoroalkyl group, a fluoroalkenyl group, a fluoroether group or a fluoropolyether group, R 8 represents an aliphatic alkyl group or an aliphatic alkenyl group, and “a” is an integer of 1 to 12.