Co-vulcanizable compositions based on fluorelastomers and polymeric compounds with a perfluoroetheric structure

Claim 1

An elastomeric composition vulcanizable with peroxides, consisting of a fluoroelastomer based on vinylidene fluoride containing small quantities of brominated or iodinated olefin as a comonomer with the function of vulcanization point, admixed with a quantity of from 1% to 25% by weight of polymeric perfluoropolyether consisting of repeating units represented by general formula: --CF.sub.2 O(CF.sub.2 O).sub.n --(CF.sub.2 CF.sub.2 O).sub.m --CF.sub.2 Q-- wherein: n and m are integers from 2 to 100, the sum n+m is comprised between 5 and 200 while the m/n ratio is comprised between 0.2 and 1.5, and where Q is a bivalent radical selected from the group consisting of ##STR9## and --CH.sub.2 --O--R--O--CH.sub.2 --, wherein: R is a bivalent radical selected from the group consisting of (a) alkylenes containing from 2 to 20 carbon atoms; (b) cycloalkylenes containing from 5 to 10 carbon atoms and such cycloalkylenes containing alkyl substituents; (c) heterocyclic radicals having a ring of 5 or 6 atoms; and (d) arylene or alkylarylene radicals having one or more benzene rings and such radicals in which benzene rings are linked to each other by O or S atoms or by --CO--, --SO--, --NH-- or --SO 2 --, or by alkylene groups, and R' is an aliphatic, or aromatic or alicyclic tetravalent radical containing from 2 to 20 carbon atoms, said polymeric perfluoropolyether being further characterized by an inherent viscosity, measured in a concentration of 0.3% by weight, at 20° C., in a solvent mixture of CF 2 Cl--CFCl 2 /dimethylformamide in a volumetric ratio of 4:1, comprised between 0.2 and 0.9 dl/g.