COMBINING ZIEGLER-NATTA AND METALLOCENE CATALYSIS - NEW HETEROPHASIC PROPYLENE COPOLYMERS FROM THE NOVEL MULTICATALYST REACTOR GRANULE TECHNOLOGY

A new process that combines the excellent morphology control of Ti-bas ed catalysts with the unique features of polyolefins from metallocenes has been devised. First, propylene is polymerized with the Ti-based c atalysts, having spherical form; then, activated metallocene catalysts are introduced into the porous PP spheres, through an in situ impregn ation and drying process, once the Ti has been deactivated. Then, the olefins polymerization, catalyzed by the metallocene, is carried out i n gas phase. This step, as well as the morphology of the as-polymerize d polymer particles, has been investigated in detail. New heterophasic copolymers (PP/EPR) having free-flowing spherical form have been achi eved, and the morphology of the copolymer spheres pointed out that the rubber is well dispersed inside the polymer granule. (C) 1997 John Wi ley & Sons, Inc.