Patent ID: 11859030
Assignee: BOREALIS AG
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A process for producing a heterophasic propylene copolymer (RAHECO) having a xylene cold soluble fraction (XCS) determined according to ISO 16152 (25° C.) of more than 30 wt %, the process comprising the steps of:
a) providing a solid Ziegler-Natta catalyst component that is free of phthalic compounds,
b) subjecting the solid Ziegler-Natta catalyst component of step a) to a batch mode catalyst prepolymerization step, wherein the solid Ziegler-Natta catalyst component is prepolymerized in the presence of one or more olefin monomer(s) selected from olefin monomers of 2 to 4 carbon atoms in the presence of an external electron donor (ED) to obtain a prepolymerized solid Ziegler-Natta catalyst,
c) polymerizing in one or more polymerization reactor(s) propylene and optionally ethylene and/or a C4 to C8 α-olefin in the presence of the prepolymerized solid Ziegler-Natta catalyst of step b), forming a first propylene homo- or copolymer,
d) polymerizing in one or more further polymerization reactor(s) in the presence of the first propylene homo- or copolymer propylene and ethylene and optionally a C4 to C8 α-olefin, to obtain the heterophasic propylene copolymer.