Catalyst system for the polymerization of alkenes to polyolefins
US6469188B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 20, 2000 |
| Grant date | Oct 22, 2002 |
| Priority date | — |
| Expiry date | Jan 20, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S526/943
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The invention provides metallocene catalyst systems for the controlled polymerization of alkenes to a wide variety of polyolefins and olefin coplymers. Catalyst systems are provided that specifically produce isotactic, syndiotactic and steroblock polyolefins. The type of polymer produced can be controlled by varying the catalyst system, specifically by varying the ligand substituents. Such catalyst systems are particularly useful for the polymerization of polypropylene to give elastomeric polypropylenes. The invention also provides novel elastomeric polypropylene polymers characterized by dyad (m) tacticities of about 55% to about 65%, pentad (mmmm) tacticities of about 25% to about 35%, molecular weights (Mw)in the range of about 50,000 to about 2,000,000, and have mmrm+rrmr peak is less than about 5%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.