Production of reflector beads from precursor beads for expandable polystyrene

Abstract

Several established methods produce precursor beads suitable for subsequent impregnation with a volatile agent for making expandable polystyrene beads. Different methods have led to production of reflector beads of crystal clear polystyrene for use as reflectors in movie screens, signs, and the like. Heretofore it has not been practical to use precursor beads as reflector beads. Many reflector beads have been made from plastics more costly than polystyrene. By the present invention, cloudy precursor beads are dispersed in an aqueous solution having a concentration of from about 1.5 to about 6 molar inorganic solute and heated to a temperature in the range from about 110.degree. to 130.degree. C. for a few minutes. The thus treated beads are rinsed with water and then dried to provide reflector beads.

Dependencies are inferred from the claim text.