Process and catalyst for producing polyolefins having low molecular weight
US6376418B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 27, 2000 |
| Grant date | Apr 23, 2002 |
| Priority date | — |
| Expiry date | Apr 27, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S526/943
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The invention provides a metallocene catalyst for use in preparing polyolefins having low molecular weight. The catalyst comprises a bridged metallocene in which one of the cyclopentadienyl rings is substituted in a substantially different manner from the other ring. The catalyst comprises a metallocene compound generally described by the formula R″(C5R4)(R′2C5C4R′4)MeQp wherein (C5R4) is a substituted cyclopentadienyl ring; (R′2C5C4R′4n) is an indenyl ring or substituted indenyl ring; each R and R′ is hydrogen or hydrocarbyl radical having from 1-20 carbon atoms, a halogen, an alkoxy, and alkoxy alkyl or an alkylamino radical, each R and R′ may be the same or different; (C5R4) has one R substituent in a distal position which is at least as bulky as a t-butyl radical; R″ is a structural bridge between the (C5R4) and (R′2C5C4R′4) rings to impart stereorigidity; Q is a hydrocarbyl radical, such as an alkyl, aryl, alkenyl, alkylaryl or arylalkyl radical having 1-20 carbon atoms or is a halogen; Me is a Group IIIB, IVB, VB, or VIB metal as positioned in the Periodic Table of Elements; and p is the valence of Me minus 2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.