Process for preparing an in situ polyethylene blend
US5589539A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 23, 1994 |
| Grant date | Dec 31, 1996 |
| Priority date | — |
| Expiry date | Nov 23, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L2308/00
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for the production of an in situ particulate polyethylene blend comprising contacting a magnesium/titanium based catalyst system including a particulate precursor with one or more alpha-olefins in each of two or more reactors connected in series, in the gas phase, under polymerization conditions, with the provisos that: PA1 (a) the particulate precursor has a particle size distribution span of no greater than about 1.5 as introduced into the first reactor in the series; PA1 (b) ethylene is introduced into each reactor; PA1 (c) optionally, an alpha-olefin having at least 3 carbon atoms is introduced into at least one reactor; PA1 (d) the mixture of ethylene polymer matrix and active catalyst formed in the first reactor in the series is transferred to the subsequent reactors in the series; and PA1 (e) the polymerization conditions in each reactor are such that a high molecular weight polymer is formed in at least one reactor and a low molecular weight polymer is formed in at least one other reactor wherein the ratio of molecular weights of the high molecular weight polymer to low molecular weight polymer in the final product is at least about 8:1.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.