New fluoroelastomers based on vinylidene fluoride, hexafluoropropene and tetrafluoroethylene

Fluoroelastomers endowed with a T.sub.g equal to or less than about -25.degree. C. and a compression set, after a 70 hour compression test at 0.degree. C. on a disc, according to ASTM D 395 test, method B, equal to or less than about 18% when measured at 23.degree. C. after 30 minutes, comprising the following monomeric composition:

• ______________________________________ vinylidene fluoride:
• 60.5-64% by weight hexafluoropropene:
• 30-33% by weight tetrafluoroethylene:
• 5-8% by weight. ______________________________________