Process for producing multimodal polyethylene in-situ blends including ultra-high molecular weight fractions

US10669410B2 · kind B2 · utility

Assignee

• Borealis AG · AT

Inventors

• Yi Liu · Linz, AT
• Qizheng Dou · Linz, DE
• Alexandra Romina Albunia · Linz, AT

Key dates

• Filing date: Dec 21, 2015
• Grant date: Jun 2, 2020
• Expiry date: Feb 5, 2036

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08L2310/00
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present application relates to a process for producing a multimodal polyethylene composition comprising the steps of polymerizing a polyethylene fraction (A-1) having a weight average molecular weight Mw of equal to or more than 500 kg/mol to equal to or less than 10,000 kg/mol and a density of equal to or more than 915 kg/m3 to equal to or less than 960 kg/m3 in one reaction step and polymerizing a polyethylene fraction (A-2) having a lower weight average molecular weight Mw as polyethylene fraction (A-1) and a density of equal to or more than 910 kg/m3 to equal to or less than 975 kg/m3 in a second reaction step of a sequential multistage process wherein one of said polyethylene fractions is polymerized in the presence of the other of said polyethylene fractions to form a first polyethylene resin (A) having a weight average molecular weight Mw of equal to or more than 150 kg/mol to equal to or less than 1,500 kg/mol, and a density of equal to or more than 910 kg/m3 to equal to or less than 975 kg/m3, wherein the weight average molecular weight Mw of the first polyethylene resin (A) is lower than the weight average molecular weight Mw of the polyethylene fraction (A-1), blendi…