Patent ID: 9000095
Filing Date: 2015-04-07
Classification: C08F,C08L

Abstract:
1. A polyethylene molding composition comprising: (A) from 25 to 50% by weight, based on the total weight of the molding composition, of a low molecular weight ethylene homopolymer A wherein the homopolymer A has a viscosity number (VN (B) from 28 to 50% by weight, based on the total weight of the molding composition, of a high molecular weight ethylene copolymer B comprising at least one comonomer in the range from 1 to 10% by weight, based on the weight of copolymer B wherein a mixture of homopolymer A and homopolymer B has a viscosity number (VN (C) from 15 to 40% by weight, based on the total weight of the molding composition, of an ultrahigh molecular weight ethylene copolymer C wherein copolymer C comprises at least one comonomer in the range from 1 to 10% by weight, based on the weight of copolymer C wherein a mixture of homopolymer A, homopolymer B and copolymer C has a viscosity number (VN wherein the polyethylene molding composition: (i) has a density between 0.948 to 0.957 g/cm (ii) has a melt flow rate (190° C./2.16 kg) between 1 to 2.7 dg/min; and (iii) has a multimodal molecular mass distribution wherein the composition is obtained in a three stage polymerization process using a magnesium titanium containing Ziegler catalyst, wherein the three reactors are connected in series, and wherein the product of the first reactor is transferred to the second reactor, and the product of the second reactor is transferred to the third reactor, the Ziegler catalyst being added to the first reactor and used in each of the three reactors.