Patent ID: 8580895

Claim:
A bimodal high density polyethylene (HDPE) resin having a molecular weight distribution (MWD), defined by the ratio of the weight average molecular weight(Mw) to the number average molecular weight (Mn), of at least 4.0 and of up to 6.0, comprising two polyethylene fractions A and B, fraction A being substantially free of comonomer and having a lower weight average molecular weight and a higher density than fraction B, each fraction prepared in different reactors of two reactors connected in series in the presence of a metallocene—containing catalyst system, wherein the metallocene is selected from at least one of the following (I) or (II): wherein each R is the same or different and is selected from hydrogen or XR′ v in which X is chosen from carbon, silicon, germanium, oxygen or nitrogen, and each R′ is the same or different and is chosen from hydrogen or a hydrocarbyl of from 1 to 20 carbon atoms and v+1 is the valence of X; R″ is a structural bridge between the two indenyl or tetrahydrogenated indenyls to impart stereorigidity that comprises a C 1 -C 4 alkylene radical, a dialkyl germanium, silicon or siloxane, or an alkyl phosphine or amine radical; Q is a hydrocarbyl radical having from 1 to 20 carbon atoms or a halogen; and M is a transition metal Group 4 of the Periodic Table or vanadium; wherein when fraction A is prepared in the first reactor of the two reactors connected in series, the ratio of the MI 2 of fraction A to the MI 2 of the bimodal HDPE resin is in the range of 1.05 to 2000; wherein when fraction B is prepared in the first reactor of the two reactors connected in series, the ratio of the HLMI of fraction B to the MI 2 of the bimodal HDPE resin is in the range of 0.06 to 0.95.