| abstract |
A multistage process for obtaining an heterophasic propylene polymer comprising the following steps: step a) contacting under polymerization conditions propylene and optionally ethylene or one or more alpha olefins in the presence of a catalysts system, supported on a porous organic polymer, comprising: n nii) one or more metallocene compounds of formula (I) n nwherein: n M is an atom of a transition metal; p is an integer from 0 to 3; X, same or different, is a hydrogen atom, a halogen atom, or a hydrocarbon group; L is a divalent bridging group; R 1 , is a linear or branched, saturated or unsaturated C 1 -C 20 -alkyl radical; R 2 is a branched C 1 -C 20 alkyl radical; n nT, equal to or different from each other, is a moiety of formula (IIIa) or (IIIb): n nwherein: the atom marked with the symbol * bonds the atom marked with the same symbol in the compound of formula (I); R 5 -R 13 , equal to or different from each other, are hydrogen atoms or hydrocarbon groups; ii) an alumoxane or a compound capable of forming an alkyl metallocene cation; and optionally iii) an organo aluminium compound; step b) contacting, under polymerization conditions, in a gas phase, ethylene and one or more alpha olefins and optionally a non-conjugated diene, in the presence of the polymer obtained in step a) and optionally in the presence of an additional organo aluminium compound. |