Patent ID: 7157410

Claim:
A perfluoropolyether ester compound having at least one ester bond, which is obtained by an esterification reaction between a perfluoropolyether diol having hydroxyl groups at both ends thereof and represented by the formula (1) and a perfluoropolyether dicarboxylic acid having carboxyl groups at both ends thereof and represented by the formula (2): HOCH 2 —R—CH 2 OH (1) HOOC—R′—COOH (2) wherein each of R and R′ is a group selected independently from the following perfluoroether groups R 1 through R 4 : R 1 : —CF 2 —(OCF 2 CF 2 ) m —(OCF 2 ) n —OCF 2 — R 2 : —(CF 2 O) j —(CF 2 CF 2 O) k —(CF 2 O) 1 —CF 2 — R 3 : —(CF 2 CF 2 CF 2 O) o —CF 2 CF 2 — R 4 : —(CF 2 CF(CF 3 )O) p —CF 2 — wherein m, n, j, k, l, o and p independently represent integers between 1 and 100.