Method and apparatus for production of stratified sheets and articles of expanded thermoplastic materials

Abstract

Abstract Method and apparatus for the production by molding, of stratified blocks, plates, sheets and articles of special shape, of cohered thermoplastic granules of material such as polystyrene, by preheating the granules to a temperature at about their softening point, followed by their expansion during molding, by insufflation with steam. The invention comprehends forming the molded articles in cohered layers of which one, for example, an outer layer may be expanded granules of polystyrene of smaller granulometry and greater density, and another layer of coarser granules and lesser density. Or there may be a central layer of granules of larger size to opposite sides of which are cohered respective layers of expanded granules of smaller size and greater density than the central or inner layer. Thereby the outer layers impart strength and improved appearance while the central layer adds improved heat insulating qualities. The invention also contemplates making the several layers of different material. For example, one layer may be granules of polystyrene and another of granules of polysulfones. Where fire retarding qualities are desired, one or more layers may be a hydrocarbon or a phosphate of chlorine or bromine. The plates, sheets, etc., may be fabricated in corrugated, fluted, channeled or embossed forms.

Inventors

• 👤 Andre Rivat-Lahousse

Bibliographic Details