Multi-stage process for the preparation of &agr;-olefin polymers having controlled stereoregularity and products prepared thereof
US6576710B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 2001 |
| Grant date | Jun 10, 2003 |
| Priority date | — |
| Expiry date | Sep 26, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F110/06
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The invention relates to the preparation of an &agr;-olefin polymer product having controlled stereoregularity, comprising the successive step of: (i) producing a first polymerization product by contacting under polymerization conditions an &agr;-olefin monomer with a polymerization catalyst system comprising a transition metal compound, a first organometal compound and a stereoregulating external electron donor to give a first polymerization reaction mixture; (ii) producing a second polymerization product by contacting additional &agr;-olefin monomer with the first polymerization reaction mixture. The controlled stereoregularity is achieved in such a way that in step (ii) the second polymerization product is produced in the presence of a stereoregularity controlling agent. The stereoregularity controlling agent e.g. a second organometal compound which contains, on an atom basis, more halogen per metal than the first organometal compound, or 0.01-1.2 % of an olefin which is not said &agr;-olefin monomer, calculated on the total molar amount of olefin and &agr;-olefin monomer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.