Method of making expandable plastic and preparation of cellular plastic therefrom

Claim 1

A METHOD OF MAKING EXPANDABLE PLASTIC MATERIALS, WHICH COMPRISES INTRODUCING GRANULES OF AN EXTRUDABLE SOLID ORGANIC THERMOPLASTIC COMPOUND SELECTED FROM THE GROUPS CONSISTING OF POLYETHYLENE, POLYVINYL CHLORIDE AND COPOLYMERS OF VINYL CHLORIDE AND VINYL ACETATE INTO A TREATING ZONE, INTRODUCING INTO THE TREATIN ZONE IN A LIQUEFIED, NORMALLY GASEOUS EXPANDING MEDIUM TO BE ABSORBED INTO THE GRANULES OF THE THERMOPLASTIC COMPOUND, SAID TREATING ZONE BEING SEALED TO THE ATMOSPHERE, SAID LIQUEFIED EXPANDING MEDIUM BEING SELECTED FROM THE GROUP CONSISTING OF DICHLORODIFLUOROMETHANE, CHLORODIFLUOROMETHANE, DISCHLORODIFLUOROMETHANE, DICHLOROTETRAFLUOROETHANE, DIFLUOROCHLOROETHANE, 1,1-DIFLUOROETHANE, AND TRICHLOROFLUOROMETHANE AND HAVING A SPECIFIC GRAVITY GREATER THAN THE SPECIFIC GRAVITY OF THE GRANULES OF THE THERMOPLASTIC COMPOUND, THE LEVEL OF THE LIQUEFIED EXPANDING MEDIUM INTRODUCED INTO THE TREATING ZONE BEING SUFFICIENTLY LESS THAN LEVEL OF THE GRANULES OF THE THERMOPLASTIC COMPOUND SO THAT THE GRANULES OF THE THERMOPLASTIC COMPOUND WILL REST AT THE BOTTOM OF THE TREATING ZONE RATHER THAN FLOATING IN THE LIQUEFIED EXPANDING MEDIUM, HEATING THE TREATING ZONE CONTAINING THE GRANULES OF THE THERMOPLASTIC COMPOUND AND THE LIQUEFIED EXPANDING MEDIUM TO A TEMPERATURE BELOW THE CRITICAL TEMPERATURE OF THE LIQUEFIED EXPANDING MEDIUM TO INCREASE THE RATE OF ABSORPTION OF THE LIQUEFIED EXPANDING MEDIUM BY THE GRANULES OF THE THERMOPLASTIC COMPOUND, ALLOWING THE GRANULES OF THE THERMOPLASTIC COMPOUND TO SOAK IN THE EXPANDING MEDIUM UNTIL THE DESIRED AMOUNT OF LIQUEFIED EXPANDING MEDIUM HAS BEEN ABSORBED BY THE GRANULES OF THERMOPLASTIC COMPOUND, WITHDRAWING THE GRANULES OF THE THERMOPLASTIC COMPOUND SOAKDE WITH THE DESIRED AMOUNT OF THE LIQUEFIED EXPANDING MEDIUM FROM THE BOTTOM OF THE ZONE WHILE PREVENTING EXPOSURE OF THE SOAKED GRANULES OF THE THERMOPLASTIC COMPOUND TO THE ATMOSPHERE, AND WITHDRAWING A SUFFICIENT AMOUNT OF THE LIQUEFIED EXPANDING MEDIUM FROM ZONE WHILE REMOVING THE SOAKED GRANULES OF THE THERMOPLASTIC COMPOUND THEREFROM SO THAT THE DIFFERENCE IN THE LEVEL OF THE GRANULE OF THE THERMOPLASTIC COMPOUND AND THE LEVEL OF THE LIQUEFIED EXPANDING MEDIUM REMAINING IN THE ZONE IS SUFFICIENT TO MAINTAIN THE GRANULES OF THE THERMOPLASTIC COMPOUND AT REST AT THE BOTTOM OF THE TREATING ZONE RATHER THAN FLOATING IN THE LIQUEFIED EXPANDING MEDIUM.

Claim 2

A METHOD OF MAKING EXPANDABLE PLASTIC MATERIALS, WHICH COMPRISES INTRODUCING GRANULES OF AN EXTRUDABLE SOLID ORGANIC THERMOPLASTIC COMPOUND SELECTED FROM THE GROUPS CONSISTING OF POLYETHYLENE, POLYVINYL CHLORIDE AND COPOLYMERS OF VINYL CHLORIDE AND VINYL ACETATE INTO A TREATING ZONE, INTRODUCING INTO THE TREATIN ZONE IN A LIQUEFIED, NORMALLY GASEOUS EXPANDING MEDIUM TO BE ABSORBED INTO THE GRANULES OF THE THERMOPLASTIC COMPOUND, SAID TREATING ZONE BEING SEALED TO THE ATMOSPHERE, SAID LIQUEFIED EXPANDING MEDIUM BEING SELECTED FROM THE GROUP CONSISTING OF DICHLORODIFLUOROMETHANE, CHLORODIFLUOROMETHANE, DISCHLORODIFLUOROMETHANE, DICHLOROTETRAFLUOROETHANE, DIFLUOROCHLOROETHANE, 1,1-DIFLUOROETHANE, AND TRICHLOROFLUOROMETHANE AND HAVING A SPECIFIC GRAVITY GREATER THAN THE SPECIFIC GRAVITY OF THE GRANULES OF THE THERMOPLASTIC COMPOUND, THE LEVEL OF THE LIQUEFIED EXPANDING MEDIUM INTRODUCED INTO THE TREATING ZONE BEING SUFFICIENTLY LESS THAN LEVEL OF THE GRANULES OF THE THERMOPLASTIC COMPOUND SO THAT THE GRANULES OF THE THERMOPLASTIC COMPOUND WILL REST AT THE BOTTOM OF THE TREATING ZONE RATHER THAN FLOATING IN THE LIQUEFIED EXPANDING MEDIUM, HEATING THE TREATING ZONE CONTAINING THE GRANULES OF THE THERMOPLASTIC COMPOUND AND THE LIQUEFIED EXPANDING MEDIUM TO A TEMPERATURE BELOW THE CRITICAL TEMPERATURE OF THE LIQUEFIED EXPANDING MEDIUM TO INCREASE THE RATE OF ABSORPTION OF THE LIQUEFIED EXPANDING MEDIUM BY THE GRANULES OF THE THERMOPLASTIC COMPOUND, ALLOWING THE GRANULES OF THE THERMOPLASTIC COMPOUND TO SOAK IN THE EXPANDING MEDIUM UNTIL THE DESIRED AMOUNT OF LIQUEFIED EXPANDING MEDIUM HAS BEEN ABSORBED BY THE GRANULES OF THERMOPLASTIC COMPOUND, WITHDRAWING THE GRANULES OF THE THERMOPLASTIC COMPOUND SOAKDE WITH THE DESIRED AMOUNT OF THE LIQUEFIED EXPANDING MEDIUM FROM THE BOTTOM OF THE ZONE WHILE PREVENTING EXPOSURE OF THE SOAKED GRANULES OF THE THERMOPLASTIC COMPOUND TO THE ATMOSPHERE, AND WITHDRAWING A SUFFICIENT AMOUNT OF THE LIQUEFIED EXPANDING MEDIUM FROM ZONE WHILE REMOVING THE SOAKED GRANULES OF THE THERMOPLASTIC COMPOUND THEREFROM SO THAT THE DIFFERENCE IN THE LEVEL OF THE GRANULE OF THE THERMOPLASTIC COMPOUND AND THE LEVEL OF THE LIQUEFIED EXPANDING MEDIUM REMAINING IN THE ZONE IS SUFFICIENT TO MAINTAIN THE GRANULES OF THE THERMOPLASTIC COMPOUND AT REST AT THE BOTTOM OF THE TREATING ZONE RATHER THAN FLOATING IN THE LIQUEFIED EXPANDING MEDIUM.