MULTIMODAL POLYETHYLENE MOULDING COMPOSITION FOR MAKING TUBES HAVING IMPROVED MECHANICAL PROPERTIES

摘要

FIELD: chemistry. ^ SUBSTANCE: invention relates to polyethylene moulding composition having multimodal molecular-weight distribution for making tubes. The composition contains the following in wt %: a first low-molecular weight ethylene homopolymer A 45-55; a second high-molecular weight copolymer B 20-40 containing ethylene and one more olefin with 4-8 carbon atoms; a third ethylene copolymer C 15-30. The composition further contains an organic polyoxy-compound in amount of 0.01-0.5 wt %. The composition is obtained in the presence of a Ziegler catalyst using a three-step suspension polymerisation method. ^ EFFECT: producing a polyethylene-based moulding composition characterised by improved processability without formation of drops. ^ 9 cl, 2 tbl, 1 ex