Patent ID: 9708479
Date: 2017-07-18
CPC Classifications: C08F,C08L

Claim:
1. A process for producing multimodal ethylene polymers in the presence of a polymerization catalyst comprising the steps of: polymerizing ethylene in a first polymerization stage at a temperature of from 30 to 70° C. and a pressure of from 1 to 150 bar in the presence of the polymerization catalyst to produce a first homo- or copolymer of ethylene; polymerizing ethylene in a second polymerization stage at a temperature of from 50 to 115° C., and a pressure of from 1 to 150 bar in the presence of hydrogen and the first homo- or copolymer of ethylene to produce a first ethylene polymer mixture comprising the first homo- or copolymer of ethylene and a second homopolymer of ethylene; copolymerizing ethylene in a third polymerization stage at a temperature of from 50 to 100° C., and a pressure of from 10 to 40 bar in the presence of an alpha-olefin comonomer having from 4 to 10 carbon atoms and the first ethylene polymer mixture to produce a second ethylene polymer mixture comprising the first ethylene polymer mixture and a third copolymer of ethylene; wherein the first homo- or copolymer of ethylene has a melt flow rate MFR