Method of catalyst transitions in olefin polymerizations

US6284849A · kind A · utility

Assignee

• Borealis A/S · DK

Inventors

• Vidar Almquist · Stathelle, NO
• Tone Aastad · Stathelle, NO
• Ingrid S. Melaaen · Kragerø, NO
• Harri Hokkanen · Helsinki, FI
• Kalle Kallio · Porvoo, FI

Key dates

• Filing date: Jan 11, 1999
• Grant date: Sep 4, 2001
• Expiry date: Jan 11, 2019

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S526/943
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A method for transitioning between two different catalysts in olefin polymerizations, a first catalyst and a second catalyst, comprising the steps of: discontinuing the feed of the first catalyst into the polymerization reactor, and introducing the second catalyst into the reactor, wherein the transition is performed between a chromium-based catalyst and a metallocene catalyst.