Polyethylene compositions, methods of making the same, and articles prepared therefrom

摘要

The invention is related to compositions suitable for the fabrication of pipes, and other articles, with excellent performance properties. The invention provides a composition, comprising a blend, wherein said blend comprises a high molecular weight ethylene-based interpolymer and a low molecular weight ethylene-based interpolymer, and the high molecular weight ethylene-based interpolymer is a heterogeneously branched linear or a homogeneously branched linear ethylene-based interpolymer, and has a density from 0.922 g/cc to 0.929 g/cc, and a high load melt index (I21) from 0.2 g/10 min to 1.0 g/10 min, and the low molecular weight ethylene-based interpolymer is heterogeneously branched linear or a homogeneously branched linear ethylene-based interpolymer, and has a density from 0.940 g/cc to 0.955 g/cc, and a melt index (I2) from 6 g/10 min to 50 g/10 min. The blend has a single peak in an ATREF profile eluting above 30° C., and has a coefficient of viscosity average molecular weight (CMv) less than −0.0032 in the log(calculated Mv) versus elution temperature, said CMv calculated in the range of elution temperatures from 70° C. to 90° C. The Mv is the viscosity average molecular weight.

主权项

1. A method of preparing a composition, said method comprising polymerizing a high molecular weight ethylene-based interpolymer and a low molecular weight ethylene-based interpolymer in one reactor, and in the presence of two Ziegler-Natta catalyst systems, and wherein the composition comprises a blend, wherein said blend comprises the high molecular weight ethylene-based interpolymer and the low molecular weight ethylene-based interpolymer, and
wherein the high molecular weight ethylene-based interpolymer is a heterogeneously branched linear ethylene-based interpolymer, and has a density from 0.922 g/cc to 0.929 g/cc, and a high load melt index (I21) from 0.2 g/10 min to 1.0 g/10 min, and wherein the low molecular weight ethylene-based interpolymer is heterogeneously branched linear ethylene-based interpolymer, and has a density from 0.940 g/cc to 0.955 g/cc, and a melt index (I2) from 6 g/10 min to 50 g/10 min; and wherein the blend has a single peak in an ATREF profile eluting above 30° C., and has a coefficient of viscosity average molecular weight (CMv) less than −0.0032 in the log(calculated Mv) versus elution temperature, said CMv calculated in the range of elution temperatures from 70° C. to 90° C., and wherein Mv is the viscosity average molecular weight.