Method for the production of co-extrudates composed of polystyrene and of a crosslinked polyvinylpyrrolidone with reduced residual styrene monomer content

摘要

A method for removing residual styrene monomers from co-extrudates comprising polystyrene and water-insoluble, crosslinked polyvinylpyrrolidone, which comprises subjecting an aqueous suspension of the particulate solid co-extrudate to a heat treatment at temperatures of 60 to 99° C., the weight ratio of solid co-extrudate to water in the suspension being 1:1.5 to 1:20, and the concentration of the suspension being kept constant during the treatment.