Patent ID: 7598312

Claim:
A process for preparing a halogenated polymer in a polymerization medium comprising liquid or supercritical carbon dioxide, said process comprising the radical polymerization of at least one halogenated monomer and cross-flow filtration of a suspension of halogenated polymer particles in a fluid phase comprising liquid or supercritical carbon dioxide, wherein the suspension of polymer particles in a fluid phase is withdrawn from the polymerization medium (suspension A) and subjected to cross flow filtration in order to obtain a concentrated suspension (suspension B), and wherein said process further comprises at least one of a), b), and c) as follows: a) prior to concentration by cross flow filtration, suspension A is cooled in a heat exchanger; b) purification of concentrated suspension B by cross-flow filtration; c) suspension A is concentrated by a method not involving cross-flow filtration prior to being subjected to cross flow filtration in order to obtain suspension B.