Patent ID: 8552127

Claim:
A process for manufacturing terpolymers by polymerization of VDF (vinylidene difluoride), TrFE (trifluoroethylene), and CFE (1-chloro-1-fluoro-ethylene) or CTFE (chlorotrifluoroethylene) monomers in the presence of a radical polymerization initiator, said process comprising the following steps: i) feeding an initial mixture of VDF and of TrFE, free of CFE and of CTFE, into an autoclave, ii) injecting the initiator mixed with water into the autoclave so as to achieve, inside the autoclave, a pressure at least equal to 80 bar, in order to form a suspension of VDF and TrFE monomers in water, iii) injecting a secondary mixture constituted of VDF, TrFE and CFE or CTFE into the autoclave, then iv) reinjecting continuously said secondary mixture into the reactor, as soon as the polymerization reaction starts, so as to maintain therein a constant pressure of at least 80 bar, wherein the initial mixture has the following composition: a proportion of VDF ranging from 25% to 95%, a proportion of TrFE ranging from 5% to 75%.