Patent ID: 8268425

Claim:
A polyethylene molding composition for cable sheathing comprising a multimodal molar mass distribution; a density at a temperature of 23° C. in the range from 0.94 to 0.950 g/cm 3 ; an MFI 190/5 in the range from 0.5 to 2.1 dg/min; from 45 to 55% by weight of a low molecular weight ethylene homopolymer A; from 30 to 40% by weight of a high molecular weight copolymer B of ethylene and another olefin having from 4 to 8 carbon atoms; and from 10 to 20% by weight of an ultra high molecular weight ethylene copolymer C, where all percentages are based on the total weight of the molding composition, wherein the molding composition has a VN 3 of 280 to 320 cm 3 /g, a notched impact toughness AFM (−30° C.) in the range from 3.5 to 4.5 kJ/m 2 , a notched impact toughness ACN (+23° C.) in the range from 12 to 16 kJ/m 2 , and an environmental stress cracking resistance (FNCT) in the range from 150 to 250 h, and each of the low molecular weight ethylene homopolymer A, high molecular weight copolymer B and ultra high molecular weight ethylene copolymer C are produced in a three-stage polymerization in the presence of a Ziegler catalyst composed of a transition metal compound and an organoaluminum compound, wherein a molar mass of the polyethylene formed in each stage is regulated in each case by means of hydrogen.