Patent ID: 7956148

Claim:
A process for the preparation of a polypropylene using a catalyst system of low porosity, the catalyst system comprising an asymmetric catalyst complex, wherein the catalyst system has a porosity of less than 1.40 ml/g determined according to DIN 66135, and wherein the asymmetric catalyst complex is in the form of solid catalyst particles, wherein the polypropylene has a. a branching index q′ of less than 1.00; and b. a strain hardening index (SHI@1s −1 ) of at least 0.30 measured by a deformation rate dε/dt of 1.00 s −1 at a temperature of 180° C., wherein the strain hardening index (SHI) is defined as the slope of the logarithm to the basis 10 of the tensile stress growth function (Ig(η E + )) as function of the logarithm to the basis 10 of the Hencky strain (Ig(ε)) in the range of Hencky strains between 1 and 3.