POLYPROPYLENE SOLID-PHASE PRESSURE FORMING - NEW PROCESS FOR THE PACKAGING INDUSTRY.

This paper describes a new process that has been developed in Netherlands by which, using only slightly modified thermoforming equipment, PP sheet is formed into thin-walled containers at temperatures below the material's crystalline melting point. Thus the problems associated with the low melt strength can be avoided while fast production speeds can be achieved because no heat of solidification has to be removed. The following topics are discussed in some detail - processing techniques; optimum plug design; PP containers properties; economics; and applications in the food packaging industry.