Homogeneous-heterogeneous catalyst system for polyolefins
US5242876A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1991 |
| Grant date | Sep 7, 1993 |
| Priority date | — |
| Expiry date | Sep 30, 2011 |
Classification
- Technology area (CPC —)General
Abstract
This invention concerns a catalyst system comprising at least one homogeneous catalyst and at least one heterogeneous catalyst, specifically, a metallocene catalyst and a conventional Ziegler-Natta catalyst, respectively. This invention is useful in the polymerization of any polymer in which separate polymerizations with a homogeneous catalyst and with a heterogeneous catalyst are possible, but preferably, polymerization of olefins, more preferably, .alpha.-olefins, and, most preferably, propylene. This invention provides a catalyst system which facilitates use of a homogeneous catalyst but eliminates the disadvantages of such a system. This invention produces a polymer with molecular weight distribution (MWD) as broad or broader than the MWD of the heterogeneous catalyst alone. Hydrogen can be used to control molecular weight distribution of a polymer produced with this invention.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.