Patent ID: 7101943

Claim:
Curable fluoroelastomers having good properties at low temperature, in particular a lower Tg and high resistance to low temperatures (TR10), said fluoroelastomers comprising units derived from the following monomers: a) vinylidene fluoride VDF b) fluorovinylethers of general formula: CFX═CXOCF 2 OR (I) wherein R is: C 2 –C 6 linear or branched (per)fluoroalkyl, C 5 –C 6 cyclic (per)fluoroalkyl, or C 2 –C 6 linear or branched (per)fluoro oxyalkyl, containing from one to three oxygen atoms, and X=F, H; c) bis-olefins having general formula: R I 1 R I 2 C═CR I 3 —Z—CR I 4 ═CR I 5 R I 6 (IA) wherein R I 1 , R I 2 , R I 3 , R I 4 , R I 5 , R I 6 equal to or different from each other, are H or C 1 –C 5 alkyl; Z is a C 1 –C 18 linear or branched alkylene or C 4 –C 18 cycloalkylene radical, optionally containing oxygen atoms or a (per)fluoropolyoxyalkylene radical; d) optionally, one or more fluorinated olefinic comonomers selected from the following: (per)fluoroalkylvinylethers (PAVE) CF 2 ═CFOR 2 f , wherein R 2 f is a C 1 –C 6 perfluoroalkyl; (per)fluoro-oxyalkylvinylethers CF 2 ═CFOX a , wherein X a is a C 1 –C 12 alkyl, or a C 1 –C 12 oxyalkyl, or a C 1 –C 12 (per)fluoro-oxyalkyl having one or more ether groups; e) optionally, C 2 –C 8 perfluoroolefins; f) optionally, one or more C 2 –C 8 non fluorinated olefinic comonomers; said fluoroelastomers comprising iodine and/or bromine atoms in the chain and/or in end position, said halogen atoms deriving from “cure site” comonomers and/or from chain transfer agents used in polymerization.