Patent ID: 8053550
Filing Date: 2011-11-08
Classification: C08J,Y02W

Abstract:
1. A process for the purification of a vinyl chloride polymer (PVC) comprising at least one compound of a heavy metal, comprising, in the order listed: (a) dissolving the PVC in a polar organic solvent having a solubility parameter not differing by more than 6 units from that of the PVC to form an organic solution; (b) adding an aqueous solution comprising water and a reagent, which reagent is either a base capable of reacting with the compound of the heavy metal or a chelating agent capable of stabilizing said compound of the heavy metal, to the organic solution, the aqueous solution being introduced in an amount such that it brings about the formation of a two-phase medium, a continuous phase of which is an organic phase, a dispersed phase of which is an aqueous phase, without phase inversion and without precipitating the PVC; (c) subjecting the two-phase medium to stirring for a time sufficient to cause the reagent to react with or stabilize the compound of the heavy metal and extract the compound of the heavy metal into the aqueous phase without precipitating the PVC; and (d) precipitating the PVC out of the two-phase medium.