MIXED COMPATIBLE ZIEGLER- NATTA/CHROMIUM CATALYSTS FOR IMPROVED POLYMER PRODUCTS

摘要

A catalyst system for polymerizing olefin- based polymers and interpolymers is disclosed. The catalyst system may include a supported chromium catalyst and a Ziegler- Natta catalyst comprising a bulking agent Mg , and Ti. The Ziegler- Natta catalysts in catalyst systems disclosed herein run exceptionally well without addition of excessive amounts of co- catalyst, thus allowing for use of chromium based supported catalysts that would otherwise be overwhelmed by aluminum alkyl. Further, embodiments disclosed herein may be run without an internal electron donor, and the lack of an internal electron donor in the system also prevents poisoning of the chromium catalysts by the internal electron donor. By including or co- feeding a chromium based catalyst with these Ziegler- Natta catalysts ,it has been found that the molecular architecture of the resulting polyolefins , such as polyethylenes, may provide for resins with excellent processing properties.