Manufacture of Foamed Polystyrene Articles (Patent No: 923665)

Inventor: Allard, Charles A.

Location: Edmonton

Comments: see above

Description: CLASS 18-125. 923,665.

MANUFACTURE OF FOAMED POLYSTYRENE ARTICLES.
Charles A. Allard Edmonton, Alberta, Canada. Application No. 071,829, filed Jan. 9, 1970. Priority date Sep. 30, 1969. (862,295) U.S.A
1 Claim.

This disclosure teaches manufacture of shaped articles of foamed polystyrene by introducing polystyrene particles (having a blowing agent therein) into a mold which is not gas tight and which has a desired configuration. The mold is heated, preferably in an oven, to a temperature in excess of the boiling point of the blowing agent and the softening point of the polystyrene to fill the mold with a solid cellular foam article. Thereafter the temperature is further increased to provide a defoamed outer skin of polystyrene about the article. An aqueous solution of sodium tripolyphosphate can be added to the polystyrene particles to speed up cell formation at the core of the article.