Patent ID: 8492446
Filing Date: 2013-07-23
Classification: B29C,B29K,C08J

Abstract:
1. A process for producing expanded PVC, which comprises: heating a mass of polymeric mixture inside a closed mold; controlling expansion of said mass due to hot molding in an environment having a constant volume defined by the closed mold, said controlling being obtained by a presence, in the mass of polymeric mixture, of microparticles of a compressible material, suitable for being contracted, under action of pressure generated by formation and expansion of microcells of blowing gas in the mass of polymeric mixture, from a first form having a larger volume, to a second form having a smaller volume; and expanding the microparticles contained in the mass of polymeric mixture, from the second form to the first form, to produce an expanded material, a density of said expanded material being determined by having at a same time, in the mass of the expanded material, both the microcells of the blowing gas and the microparticles in their first form.