Process and catalyst for producing isotactic polyolefins
US5416228A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 7, 1991 |
| Grant date | May 16, 1995 |
| Priority date | — |
| Expiry date | Oct 7, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F4/61927
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
This invention is for a metallocene catalyst component useful in preparing isotactic polyolefins, a catalyst system using this component and a process for polymerizing olefins using the catalyst component. The catalyst component consists of a bridged metallocene in which one of the cyclopentadienyl rings is substituted in a different manner from the other ring. One of the cyclopentadienyl ligands contains a bulky group in one and only one distal position and the other cyclopentadienyl ligand has bilateral or pseudobilateral symmetry. There is a steric difference between the two Cp rings. The catalyst component is a stereorigid metallocene described by the formula: EQU R" (CpR.sub.n)(CpR'.sub.m)MeQ.sub.k wherein each Cp is a cyclopentadienyl or substituted cyclopentadienyl ring; each R.sub.n and R'.sub.m is a hydrocarbyl radical having 1-20 carbon atoms; R" is a structural bridge between the two Cp rings imparting stereorigidity to the Cp rings; Me is a transition metal; and each Q is a hydrocarbyl radical or is a halogen. R'.sub.m is selected so that (CpR'.sub.m) is a sterically different substituted cyclopentadienyl ring than (CpR'.sub.n). The use of a metallocene catalyst compone…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.