Polyethylene coated with wax and polystyrene or polytetrafluoroethylene and preparation of cellular article therefrom

Claim 1

THE MEHTOD OF PRODUCING CELLULAR PLASTIC ARTICLES, WHICH METHOD COMPRISES THE STEPS OF: ADMIXING THROUGHLY FROM ABOUT 90% TO ABOUT 80% BY WEIGHT OF SOLID POLYETHYLENE IN THE FORM OF CUBES OF THE ORDER OF 5/16" ON A SIDE WITH FROM ABOUT 10% TO ABOUT 20% BY WEIGHT OF A FINELY DIVIDED HARDENING PLASTIC FOR POLYETHYLENE, SAID HARDENING PLASTIC BEING SELECTED FROM THE GROUP CONSISTING OF POLYSTYRENE AND POLYTETRAFLUOROETHYLENE AND HAVING A PARTICLE SIZE OF THE ORDER OF ABOUT 60 MESH, ADDING TO THE MIXTURE OF POLYETHYLENE AND THE HARDENING PLASTIC A MOLTEN MICROCRYSTALLINE WAX HAVING A MELTING POINT BETWEEN ABOUT 152*F. AND ABOUT 156*F. IN AMOUNT SUFFICIENT TO COAT THE SURFACES OF EACH CUBE OF POLYETHYLENE WITH A THIN FILM OF THE WAX, SO THAT A COMPOSITE MATERIAL IS FORMED CONSISTING ESSENTIALLY OF THE CUBES OF POLYETHYLENE COATED WITH A THIN FILM OF THE WAX WITH THE PARTICLES OF THE HARDENING PLASTIC BEING ADHERED TO THE POLYETHYLENE CUBES BY THE FILM OF WAX, MIXING THE COMPOSITE MATERIAL SO FORMED WITH FROM ABOUT 1% TO ABOUT 2% BY WEIGHT, BASED ON THE TOTAL MIXTURE, OF DINITROSOPENTAMETHYLENE-TETRAMINE BLOWING AGENT IN THE FORM OF PARTICLES HAVING A PARTICLE SIZE OF THE ORDER OF ABOUT 60 MESH, AND EXTRUDING THE RESULTANT MIXTURE OF POLYETHYLENE, WAD, HARDENING PLASTIC, AND DINITROSO-PENTAMETHYLENETETRAMINE AT AN ELEVATED TEMPERATURE AND PRESSURE INTO THE FORM OF A CELLULAR PLASTIC ARTICLE.