Process for the manufacture of branched polypropylene

Abstract

A process for manufacturing a branched polypropylene, said branched polypropylene having a branching index g′ of less than 1.00, the process comprising the step of polymerizing propylene and optionally one or more other comonomers under non-supercritical conditions in a reaction vessel, wherein: c. the pressure during the polymerization of propylene and optionally one or more other comonomers in said reaction vessel is at least 45.4 bar; d. the temperature during the polymerization of propylene and optionally one or more other comonomers in said reaction vessel is below 90° C.; and c. the polymerization of propylene and optionally one or more other comonomers is conducted in said reaction vessel in the presence of a catalyst system having a surface area of not more than 350 m2/g, measured according to ISO 9277, and said catalyst system comprises a metallocene catalyst having zirconium as the transition metal.

Dependencies are inferred from the claim text.