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 indeno[1,2-b]indolyl zirconium complex. The process produces polyethylene characterized by good incorporation of the α-olefin and moderate long-chain branching. The process is capable of forming high molecular weight polyethylene and has good catalyst activity.
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 C 3 -C 10 α-olefin and a catalyst comprising an activator and a supported complex to produce polyethylene with good incorporation of the α-olefin and moderate long-chain branching as indicated by a viscosity enhancement factor between 2.0 and 4.0; wherein the process provides polyethylene having weight-average molecular weight greater than 250,000; wherein the catalyst has an activity ratio as defined herein greater than 2; and wherein the complex has a structure selected from the group consisting of:
wherein R 1 is selected from the group consisting of methyl, benzyl, and p-chlorophenyl; R 2 is selected from the group consisting of methyl and hydrogen; each R 3 is methyl or both taken together are tetramethylene 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 the activator is selected from the group consisting of alumoxanes, alkylaluminum compounds, organoboranes, ionic borates, ionic aluminates, aluminoboronates, and combinations thereof.
3. The process of claim 2 wherein the activator is methylalumoxane.
4. The process of claim 1 wherein each L is Cl.
5. The process of claim 1 wherein the C 3 -C 10 α-olefin is selected from the group consisting of propylene, 1-butene, 1-hexene, 1-octene, and combinations thereof.
6. The process of claim 1 wherein 63 mmoles of 1-butene per mole of ethylene forms polyethylene with greater than 5 tertiary carbons per 1000 carbons.
7. The process of claim 1 wherein the supported complex is supported on silica.
8. The process of claim 1 wherein the polyethylene has a weight-average molecular weight greater than 350,000.
9. The process of claim 1 wherein the process has good hydrogen sensitivity such that introduction of 0.82 mmoles of hydrogen per mole of ethylene reduces the weight-average molecular weight by at least 60%.
10. The process of claim 1 wherein the complex has the structure:
in which each L is independently selected from the group consisting of halide, alkoxy, aryloxy, siloxy, alkylamino, and C 1 -C 30 hydrocarbyl.
11. The process of claim 1 wherein the complex has the structure:
in which each L is independently selected from the group consisting of halide, alkoxy, aryloxy, siloxy, alkylamino, and C 1 -C 30 hydrocarbyl.
12. The process of claim 1 wherein the complex has the structure:
in which R 1 is selected from the group consisting of methyl, benzyl, and p-chlorophenyl; and each L is independently selected from the group consisting of halide, alkoxy, aryloxy, siloxy, alkylamino, and C 1 -C 30 hydrocarbyl.
13. The process of claim 1 wherein the complex has the structure:
in which each L is independently selected from the group consisting of halide, alkoxy, aryloxy, siloxy, alkylamino, and C 1 -C 30 hydrocarbyl.