Process for producing improved foamed PVC and plastic material based on foamed PVC obtained therewith

摘要

A process for the production of expanded PVC of the type includes heating a mass of polymeric mixture inside a closed mold; controlling the expansion of the mass in an environment having a constant volume defined by the closed mold, control being performed by the presence, in the mass of polymeric mixture, of microparticles of a compressible material, suitable for being contracted, under the action of the pressure generated by the formation and expansion of microcells of expanding gas in the same mass, from an initial form having a larger volume, to a form having a smaller volume; and expanding the microparticles, from their configuration to the initial configuration, the density of the expanded material thus obtained being determined by the contemporary presence of both microcells of expanding gas and the microparticles in their configuration having a larger volume.