Processes for preparing metallocene-based catalyst systems for the control of long chain branch content
AssigneeChevron Phillips Chemical Company LP
InventorsQing Yang, Max P. McDaniel, Tony R. Crain
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Abstract
Methods for preparing a metallocene-based catalyst composition that can impact the long chain branching of ethylene homopolymers and copolymers produced using the catalyst composition are described. The catalyst composition can be prepared by contacting a metallocene compound, a hydrocarbon solvent, and a first organoaluminum compound for a first period of time to form a metallocene solution, and then contacting the metallocene solution with an activator-support and a second organoaluminum compound for a second period of time to form the catalyst composition.
Claims22
A polymerization process comprising:
- (A) contacting a metallocene compound, a hydrocarbon solvent, and a first organoaluminum compound for a first period of time to form a metallocene solution, and contacting the metallocene solution with an activator-support and a second organoaluminum compound for a second period of time to form a high LCB catalyst composition;
- (B) contacting the metallocene compound, the hydrocarbon solvent, the activator-support, and the second organoaluminum compound to form a low LCB catalyst composition;
- (C) contacting the high LCB catalyst composition and/or the low LCB catalyst composition with ethylene and an optional olefin comonomer in a polymerization reactor system under polymerization conditions to produce an ethylene polymer having a long chain branch (LCB) content;
- and
- (D) controlling a relative amount of the high LCB catalyst composition and the low LCB catalyst composition in step (C) to adjust the LCB content of the ethylene polymer.
Dependencies are inferred from the claim text.