Olefin polymerization process
View Patent ↗A slurry process for polymerizing ethylene is disclosed. The process comprises polymerizing ethylene in the presence of an α-olefin and a catalyst comprising an activator and a supported bridged bis-indeno[2,1-b]indolyl zirconium complex. The process uses a highly active catalyst and provides polyethylene characterized by a high level of long-chain branching.
1. A slurry process which comprises polymerizing ethylene at a temperature within the range of about 40° C. to about 90° C. in the presence of a catalyst comprising an activator and a supported complex to produce polyethylene with high long-chain branching as indicated by a viscosity enhancement factor of greater than 7, wherein the catalyst has an activity ratio as defined herein greater than 4, and wherein the complex has the structure:
wherein each R 1 is independently selected from the group consisting of C 1 -C 6 n-alkyl; each R 2 is independently selected from the group consisting of H, F, and C 1 -C 10 hydrocarbyl; Q is selected from the group consisting of methylene and dimethylsilyl; and each L is independently selected from the group consisting of halide, alkoxy, aryloxy, siloxy, alkylamino, and C 1 -C 30 hydrocarbyl.
2. The process of claim 1 wherein R 1 is methyl.
3. The process of claim 1 wherein each L is Cl.
4. The process of claim 1 further comprising polymerizing ethylene in the presence of a C 3 -C 10 α-olefin selected from the group consisting of propylene, 1-butene, 1-hexene, 1-octene, and combinations thereof.
5. The process of claim 4 wherein the C 3 -C 10 α-olefin is selected from the group consisting of 1-butene, 1-hexene, and 1-octene.
6. The process of claim 1 wherein the polyethylene has a molecular weight distribution (M w /M n ) of less than 4.5.
7. The process of claim 1 wherein the complex has the structure:
wherein each L is independently selected from the group consisting of halide, alkoxy, aryloxy, siloxy, alkylamino, and C 1 -C 30 hydrocarbyl.
8. The process of claim 1 wherein the complex has the structure:
wherein each L is independently selected from the group consisting of halide, alkoxy, aryloxy, siloxy, alkylamino, and C 1 -C 30 hydrocarbyl.
9. The process of claim 1 wherein the activator is selected from the group consisting of alumoxanes, alkylaluminum compounds, organoboranes, ionic borates, ionic aluminates, aluminoboronates, and combinations thereof.
10. The process of claim 9 wherein the activator is methylalumoxane.