Patent ID: 8668995

Claim:
A compound of the formula (1) C 6 H 4 —(O—Z—R—X) 2 (1) wherein Z is —CH 2 CH 2 O— or —CH 2 CH(OH)CH 2 O—, R is —CH 2 CF 2 CF 2 CF 2 O(CF 2 CF 2 CF 2 CF 2 O) n CF 2 CF 2 CF 2 CH 2 —, n is a real number of 0 to 20, X is —OH, —O(CH 2 ) m OH, —OCH 2 CH(OH)CH 2 OH, —OCH 2 CH(OH)CH 2 O—C 6 H 5 or —OCH 2 CH(OH)CH 2 O—C 6 H 4 —OCH 3 , m is an integer of 1 to 6.