PROCESS FOR SEPARATING AND RECOVERING POLYSTYRENE FROM POLYSTYRENE CONTAINING MATERIALS

摘要

A process for separating and recovering polystyrene from polystyrene containing material wherein the polystyrene containing material is contacted with liquid sulphur dioxide. The polystyrene-sulphur dioxide system forms two phases, an upper phase which contains the polystyrene and a lower phase which contains the pure sulphur dioxide solvent which can be reused in the process. The polystyrene is recovered from the upper polystyrene containing phase by boiling off the sulphur dioxide, which if desired is returned to the process, optionally after removing low molecular weight portions of polystyrene. Apparatus for performing the process is also disclosed.