Patent ID: 6093751
Filing Date: 2000-07-25
Classification: B65D,C08J,C08L,Y10T

Abstract:
A method of producing a substantially open-cell polystyrene sheet, comprising the steps of:(a) forming a mixture comprised of (i) from 30 to 95% of polystyrene beads which contain an aliphatic hydrocarbon with 4-6 carbon atoms, (ii) from 0 to 65% of virgin polystyrene beads, and (iii) from 0.2 to 10% of a nucleating agent,(b) forming a melt of the mixture obtained in step (a) by heating the mixture inside an extruder(c) bringing the melted mixture to a temperature of 130-150.degree. C. in the final portion of the extruder, and(d) extruding the melted mixture in a lower-pressure atmosphere to produce an expanded sheet thereof.