Process control for long chain branching control in polyethylene production
US10155831B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 2016 |
| Grant date | Dec 18, 2018 |
| Priority date | — |
| Expiry date | Nov 9, 2036 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F2500/09
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Polymerization process control methods for making polyethylene are provided. The process control methods include performing a polymerization reaction in a polymerization reactor to produce the polyethylene, where ethylene, and optionally one or more comonomers, in the polymerization reaction is catalyzed by an electron donor-free Ziegler-Natta catalyst and an alkyl aluminum co-catalyst. A melt flow ratio (I21/I2) of the polyethylene removed from the polymerization reactor is measured and an amount of long chain branching (LCB) of the polyethylene from the polymerization reactor is controlled by adjusting a weight concentration of the alkyl aluminum co-catalyst present in the polymerization reactor. In addition, an electron donor-free Ziegler-Natta catalyst productivity of the polyethylene being produced in the polymerization reactor is measured from which the amount of LCB of the polyethylene from the polymerization reactor is determined using the measured electron donor-free Ziegler-Natta catalyst productivity and a predetermined relationship between the electron donor-free Ziegler-Natta catalyst productivity and the LCB.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.