US Patent 7754840 Bimodal high density polyethlyene

The present invention is directed to a bimodal polyethylene comprising ethylene derived units and units derived from at least one of a C4 to C12 olefin; wherein the polyethylene has a density of from 0.940 to 0.970 g/cm3; an I21/I2 of 80 or more; a residual Group 4 metal content of 2.0 ppm or less: a Mw/Mn of from 20 to 60; and wherein the polyethylene comprises a high molecular weight component and a low molecular weight component, the high molecular weight component present from 40 to 60 weight percent based on the total polyethylene, and wherein the bimodal polyethylene has a weight avenge molecular weight Mw of 180,000 a.m.u. or more.