Patent ID: 7910671

Claim:
Linear perfluoropolyethers having the following structure formula: T-O(CF 2 O) n (CF 2 CF 2 O) m (CF 2 CF 2 CF 2 O) r (CF 2 CF 2 CF 2 CF 2 O) s -T 1 (I) wherein: T and T 1 , equal to or different from each other are selected from the group consisting of CF 3 —, CF 3 CF 2 —, C 3 F 7 —, C 4 F 9 —, ClCF 2 —, and ClCF 2 CF 2 —; n, m, r, s are integers such that the number average molecular weight is comprised between 700 and 100,000; the m/n ratio is comprised between 2 and 20; the (r+s)/(n+m+r+s) ratio is comprised between 0.05 and 0.2; the n/(n+m+r+s) ratio ranges from 0.05 to 0.40; wherein the perfluorooxyalkylene units are statistically distributed along the polymeric chain.