Polyethylene moulding compound with an improved ESCR/stiffness relation and an improved swelling rate, a method for the production thereof and the use thereof

US6713561B1 · kind B1 · utility

Assignee

• Basell Polyolefine GmbH · DE

Inventors

• Joachim Berthold · Prien am Chiemsee, DE
• Ludwig Bohm · Mainz, DE
• Johannes-Friedrich Enderle · Frankfurt, DE
• Reinhard Schubbach · Bergen, DE

Key dates

• Filing date: Mar 21, 2002
• Grant date: Mar 30, 2004
• Expiry date: Apr 5, 2022

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08L2308/00
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The invention relates to a polyethylene moulding compound having a multimodal molecular weight distribution which has an overall density of ≧0.940 g/cm3 and an MFI190/5 in the range from 0.01 to 10 dg/min. The moulding compound according to the invention comprises an amount of from 30 to 60% by weight of low-molecular-weight ethylene homopolymer A which has a viscosity number VNA in the range from 40 to 150 cm3/g, an amount of from 30 to 65% by weight of high-molecular-weight copolymer B comprising ethylene and a further olefin having from 4 to 10 carbon atoms which has a viscosity number VNB in the range from 150 to 800 cm3/g, and an amount of from 1 to 30% by weight of ultrahigh-molecular-weight ethylene homopolymer C which has a viscosity number VNC in the range from 900 to 3000 cm3/g.The invention also relates to a method for the production of the moulding compound in a three-step process, and to the use thereof for the production of hollow articles.