Patent ID: 8110644

Claim:
A method of preparing a pipe or tubing, comprising: creating a Ziegler-Natta catalyst, wherein the Ziegler-Natta catalyst is produced by a process comprising: contacting an alkyl magnesium compound with an alcohol to form a magnesium dialkoxide compound; contacting said magnesium dialkoxide compound with a first agent selected from ClTi(O 1 Pr) 3 , ClSi(Me) 3 and combinations thereof, to form a reaction product “A”; contacting said reaction product “A” with a second agent comprised of TiCl 4 /Ti(OBu) 4 to form reaction product “B”; contacting said reaction product “B” with a third agent comprised of TiCl 4 to form reaction product “C”; contacting said reaction product “C” with a fourth agent comprised of TiCl 4 to form reaction product “D”; and contacting said reaction product “D” with a fifth agent selected from TMA, TIBAl, TEAl, n-octyl aluminum, n-hexyl aluminum and combinations thereof, to form said catalyst; forming a bimodal polyethylene at least partially in a slurry process using the Ziegler-Natta catalyst, wherein the bimodal polyethylene exhibits a density of from 0.930 g/cc to 0.960 g/cc, and a molecular weight distribution of from 10 to 25; processing the polyethylene under conditions in which a specific energy input (SEI) is less than 300 kWh/ton; and forming a pipe or tubing article, wherein said article has a PENT of at least 1500 hours.