Patent ID: 7754840

Claim:
A bimodal polyethylene comprising ethylene derived units and units derived from at least one of a C 4 to C 12 olefin; wherein the polyethylene has a density of from 0.940 to 0.970 g/cm 3 ; an I 21 /I 2 of 80 or more; a residual zirconium or hafnium metal content; 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 high molecular weight component has a weight average molecular weight Mw of greater than 100,000 a.m.u., and wherein the high molecular weight component has a Mw/Mn between 4.50 and 6.88, wherein said bimodal polyethylene is formed in a single reactor by contacting olefins and a catalyst composition comprising a Group 15 containing compound and a bulky ligand metallocene catalyst compound; wherein the Group 15 containing metal compound is represented by the formulae: wherein M is a Group 4, 5 or 6 metal; each X is independently a leaving group; y is 0 or 1; n is the oxidation state of M; m is the formal charge of the ligand comprising the YZL or YZL′ groups; L is Nitrogen; L′ is a Group 15 or 16 element or Group 14 containing group; Y is Nitrogen; Z is Nitrogen; R 1 and R 2 are independently a C 1 to C 20 hydrocarbon group, a heteroatom containing group having up to twenty carbon atoms, silicon, germanium, tin, lead, or phosphorus; wherein R 1 and R 2 may be interconnected to each other; R 3 is absent or a hydrocarbon group, hydrogen, a halogen, a heteroatom containing group; R 4 and R 5 are independently an alkyl group, an aryl group, substituted aryl group, a cyclic alkyl group, a substituted cyclic alkyl group, a cyclic arylalkyl group, a substituted cyclic arylalkyl group or a multiple ring system; wherein R 4 and R 5 may be interconnected to each other; R 6 and R 7 are independently absent, hydrogen, an alkyl group, halogen, heteroatom or a hydrocarbyl group; R* is absent, hydrogen, a Group 14 atom containing group, a halogen, or a heteroatom containing group, and wherein a polyethylene pipe comprising the bimodal polyethylene has a predicted D-4 Tc for 110 mm pipe of less than −5° C. when tested according to ISO DIS 13477/ASTM F1589.