Production of multimodal polythylene
US6346575B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1999 |
| Grant date | Feb 12, 2002 |
| Priority date | — |
| Expiry date | Sep 24, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L2314/06
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for the preparation of polyethylene resins having a multimodal molecular weight distribution which comprises:(i) contacting ethylene monomer and a comonomer comprising an alpha-olefin having from 3 to 10 carbon atoms with a first catalyst system in a first reactor under first polymerisation conditions to produce a first polyethylene having a first molecular weight, an HLMI of not more than 0.5 g/10 min and a first density of not more than 0.925 g/ml and the first catalyst system comprising (a) a metallocene catalyst comprising a bis tetrahydroindenyl compound of the general formula (IndH4)2R″MQ2 in which each Ind is the same or different and is indenyl or substituted indenyl, R″ is a bridge which comprises a C1-C20 alkylene radical, a dialkyl germanium or silicon or siloxane, or an alkyl phosphine or amine radical, which bridge is substituted or unsubstituted, M is a Group IVB transition metal or vanadium and each Q is hydrocarbyl having 1 to 20 carbon atoms or halogen; and (b) a cocatalyst which activates the catalyst component;(ii) providing a second polyethylene having a second lower molecular weight and second higher density than the first polyethylene, th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.