Catalyst systems for improved stereoselectivity and broader molecular weight distribution in polymerization of olefins
US6133385A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 6, 1994 |
| Grant date | Oct 17, 2000 |
| Priority date | — |
| Expiry date | Apr 6, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P20/52
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The present invention provides a catalyst system and a process for the polymerization of olefin that exhibits improved selectivity and broader molecular weight distribution in the polymer product. The catalyst system includes a conventional supported Ziegler-Natta catalyst in combination with a mixture of at least two electron donors, both having the general formula SiR.sub.m (OR').sub.4-m where R is selected from the group consisting of an alkyl group, a cycloalkyl group, an aryl group and a vinyl group; R' is an alkyl group; and m is 0-3, wherein when R is an alkyl group, R may be identical with R'; when m is 0, 1 or 2, the R' groups may be identical or different; and when m is 1, 2 or 3, the R groups may be identical or different. Preferably, one electron donor is described by the formula: ##STR1## wherein R.sub.1 and R.sub.4 are both an alkyl or cycloalkyl group containing a secondary or tertiary carbon atom attached to the silicon atom, R.sub.1 and R.sub.4 being the same;; R.sub.2 and R.sub.3 are alkyl or aryl groups, R.sub.2 and R.sub.3 being the same or different; and the other electron is described by the formula: ##STR2## wherein R'.sub.1 is an alkyl or cycloalkyl group co…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.