Mechanical pulverization of refrigerated plastics

Claim 1

A PROCESS OF CHILLING AND PULVERIZING BY IMPACT A TOUGH THERMOPLASTIC RESIN HAVING A HIGH IMPACT STRENGTH OF BETWEEN 2 AND 11.5 FOOT POUNDS PER INCH OF NOTCH 1/2 INCH 1/2 INCH NOTCHED BAR IZOD TEST, SAID PROCESS COMPRISING CONTACTING PIECES OF THE MATERIAL WITH A REFRIGERANT WHICH IS A LIQUEFIED GAS HAVING A TEMPERATURE ADJACENT THAT OF LIQUID NITROGEN, WHICH HAS BEEN VAPORIZED AND IS AT SLIGHTLY SUPERATMOSPHERIC PRESSURE WHILE FEEDING THE SAME TO AN IMPACT MILL, SPRAYING SAID REFRIGERANT IN LIQUID PHASE ONTO SAID MATERIAL CLOSELY ADJACENT SAID MILL AND AFTER IT HAS BEEN COOLED BY SAID VAPORIZED REFRIGERANT TO CHILL AT LEAST OUTER PORTIONS OF SAID MATERIAL TO WELL BELOW ITS BRITTLE POINT, SUBJECTING THE MATERIAL TO IMPACTS IN SAID MILL, SEPARATING PARTICLES BELOW A PREDETERMINED SIZE FROM THOSE ABOVE SAID SIZE, AND PRECOOLING THE MATERIAL FED TO SAID MILL BY SAID CONTACT WITH VAPORIZED REFRIGERANT FROM SAID MILL.