MULTIMODAL POLYETHYLENE MOLDING COMPOSITION FOR PRODUCING PIPES HAVING IMPROVED MECHANICAL PROPERTIES

摘要

A polyethylene molding composition having a multimodal molecular mass distribution and comprising from 45 to 55 % by weight of a low molecular weight ethylene homopolymer A, from 20 to 40 % by weight of a high molecular weight copolymer B comprising ethylene and another olefin having from 4 to 8 carbon atoms and from 15 to 30 % by weight of an ultrahigh molecular weight ethylene copolymer C can be prepared in the presence of a Ziegler catalyst in a three-stage process and is highly suitable for producing pipes having excellent mechanical properties.