Process for the preparation of polypropylene with improved productivity

US9353203B2 · kind B2 · utility

Assignee

• Borealis AG · AT

Inventors

• Wolfgang Neissl · Lichtenberg, AT
• Dietrich Gloger · Linz, AT
• Thomas Horill · Deutsch-Wagram, AT
• Martina Sandholzer · Linz, AT
• Gregory Potter · Linz, AT

Key dates

• Filing date: Jul 30, 2013
• Grant date: May 31, 2016
• Expiry date: Jul 30, 2033

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08L2205/025
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A process for the preparation of a polypropylene in a sequential polymerization process including at least two polymerization reactors connected in series. The polymerization takes place in the presence of a Ziegler-Natta catalyst, and said Ziegler-Natta catalyst includes (a) a pro-catalyst that has a compound of a transition metal, a compound of a metal which metal is selected from one of the groups 1 to 3 of the periodic table (IUPAC), and an internal electron donor, (b) a co-catalyst, and (c) an external donor. The ratio of catalyst feed rate to propylene feed rate in the first polymerization reactor is 1.0 to 4.5 g/t.