PROCESS FOR THE PRODUCTION OF HETEROPHASIC POLYMER COMPOSITIONS, AND COMPOSITIONS THUS OBTAINED

摘要

Process for the preparation of heterophasic polyolefin compositions comprising; i) a stage where a) the polymerization of the propylene to form a crystalline propylene or ethylene polymer, and b) the copolymerization of the ethylene with a C3-C10 alpha -olefin take place to form an elastomeric copolymer; said stage being carried out in the presence of a Ziegler-Natta catalyst; ii) a treatment stage where the polymer obtained in polymerization stage (i) is made to contact with: a) a compound capable of deactivating the catalist present in said stage i); and b) a catalyst (2) obtained by containing (I) a compound containing a transition metal M, and at least one ligand coordinated with the metal M by a pi bond, and (II) a cocatalyst; iii) a copolymerization stage where the ethylene and a C3-C10 alpha -olefin are polymerized in the presence of a polymer treated as in stage (ii), and said catalyst (2).