Patent ID: 8258090

Claim:
Polymers of formula T-O-[A-B] z -[A-B′] z′ -A-T′ (I) wherein: A=—(X) a —O-A′-(X′) b — wherein A′ is a perfluoropolyether chain comprising one or more repeating units selected from the group consisting of (CF 2 O), (CF 2 CF 2 O), (CF 2 CF 2 CF 2 O), and (CF 2 CF 2 CF 2 CF 2 O), optionally comprising unit (CF(CF 3 )O), (CF(CF 3 )CF 2 O), (CF 2 CF(CF 3 )O); X, X′, equal to or different from each other, are —CF 2 —, —CF 2 CF 2 —, optionally —CF(CF 3 )—; a, b, equal to or different from each other, are integers equal to 0 or 1, with the proviso that the block A linked to the end group T-O— has a=1 and the block A linked to the end group T′ has b=0; B is a block formed of units deriving from one or more olefins, wherein at least one of them is homopolymerizable by radical route, having formula: —[(CR 1 R 2 —CR 3 R 4 ) j (CR 5 R 6 —CR 7 R 8 ) j′ ]— (1a) wherein j is an integer from 1 to 5, j′ is an integer from 0 to 4 with the proviso that (j+j′) is higher than 2 and lower than 5; R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , equal to or different from each other, are selected from halogen; H; C 1 -C 6 (per)haloalkyl, wherein the halogen is F, Cl; C 1 -C 6 alkyl, optionally containing heteroatoms; or C 1 -C 6 oxy(per)fluoroalkyl; z is an integer higher than or equal to 2; z′ is 0 or an integer; z, z′ are such that the number average molecular weight of the polymer of formula (I) is in the range 500-500,000; B′ is a block deriving from one or more olefins and having formula (1a), but having at least one of the substituents R 1 to R 8 different than in block B, (j+j′) being higher than or equal to 2 and lower than 5; the end groups T and T′, equal to or different from each other, are perfluoroalkyls from 1 to 3 carbon atoms, one fluorine atom can be substituted by one chlorine or hydrogen atom; C 1 -C 6 non fluorinated alkyl groups.