Process for producing a homogeneous polyethylene material in the presence of a catalyst
US6455642B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 2000 |
| Grant date | Sep 24, 2002 |
| Priority date | — |
| Expiry date | Nov 7, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S526/905
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The present invention concerns a process for producing homogeneous polyethylene materials and processes for making high density, medium density and low density films therefrom. The process involves producing a polyethylene composition in a multistage reaction sequence of successive polymerization stages in the presence of an ethylene-polymerizing catalyst system. According to the invention, the process is carried out using an unsupported catalyst having magnesium and titanium as active constituents, in at least one loop polymerization stage and at least one gas phase polymerization stage and, operated with different amounts of hydrogen and comonomers to produce a high molecular weight portion in one of the polymerization stages and a low molecular weight portion in another so as to provide a polyethylene composition with the low molecular weight part having a MFR2 of 250 g/10 min or more. With this process it is possible to obtain homogeneous bimodal polyethylene material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.