Patent ID: 11952481
Assignee: BOREALIS AG
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C | IPC C

Claim 9:
10. A process for preparing the heterophasic polypropylene composition according to claim 1, comprising the steps of:
a) polymerizing propylene and optionally comonomer units selected from ethylene or alpha-olefins with 4 to 12 carbon atoms in a first polymerization reactor in the presence of a single-site catalyst to produce a first polymerization mixture comprising a first propylene homo- or copolymer and the single-site catalyst;
b) transferring the first polymerization mixture into a second polymerization reactor;
c) polymerizing propylene and comonomer units selected from ethylene or alpha-olefins with 4 to 12 carbon atoms in said second polymerization reactor in the presence of said single-site catalyst to produce a second polymerization mixture comprising a second propylene copolymer, said first propylene homo- or copolymer and the single-site catalyst, wherein the weight ratio of said first propylene homo- or copolymer to said second propylene copolymer is in the range of 20:80 to 55:45;
d) withdrawing said second polymerization mixture from said second polymerization reactor; and
e) compounding said second polymerization mixture optionally with the addition of additives to form the heterophasic polypropylene composition.