Coated pipes having improved mechanical properties at elevated temperatures and a method of production thereof

US8142871B2 · kind B2 · utility

Assignee

• Borealis Technology Oy · FI

Inventors

• Martin Anker · Karlskrona, SE
• Siw Bodil Fredriksen · Skien, NO
• Pal Christian Bentzrod · Stavern, NO
• Mats Bäckman · Gothenburg, SE
• Leif Leiden · Hammarland, FI
• Markku Vahteri · Porvoo, FI
• Petri Rekonen · Helsinki, FI

Key dates

• Filing date: Dec 10, 2008
• Grant date: Mar 27, 2012
• Expiry date: Apr 23, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/1397
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present invention deals with coated pipes having a layer of multimodal polyethylene. The multimodal ethylene copolymer is a copolymer of ethylene with one or more alpha-olefin comonomers having from 4 to 10 carbon atoms and has a weight average molecular weight of from 70000 g/mol to 250000 g/mol and a melt index MFR2 of from 0.05 g/10 min to 5 g/10 min, a melt index MFR5 of from 0.5 to 10 g/10 min and a density of from 945 kg/m3 to 958 kg/m3. The coatings have a high stiffness, good properties at elevated temperatures and acceptable stress-cracking properties.