Process for producing terpolymers of propylene, ethylene and another alpha -olefin

摘要

A process for producing terpolymers of propylene (as a main monomer), ethylene and another alpha -olefin having superior and well-balanced physical properties, almost without forming soluble polymer is provided. This process is characterized by preliminarily activating a catalyst consisting of a titanium trichloride composition and a specified organoaluminum halide, with a small amount of an alpha -olefin of 2 to 12 carbon atoms, a trialkylaluminum and an aromatic ester, and copolymerizing specified amounts of propylene, ethylene and an alpha -olefin of 4 to 12 carbon atoms in the presence of the preliminarily activated catalyst obtained above.