Patent ID: 7423098
Filing Date: 2008-09-09
Classification: C08F,Y10S

Abstract:
1. A process which comprises polymerizing ethylene with a C 6 -C 10 alpha-olefin in two slurry reaction zones in the presence of a single-site catalyst system comprising an activator and a supported Group 4-6 transition metal complex to produce polyethylene, wherein from about 35 to about 75 wt. % of the polyethylene is produced in a first reaction zone with a hydrogen to ethylene molar ratio in the vapor phase of from about 0.00005:1 to about 0.01:1 to produce a first-zone material having a melt index of from about I to about 300 dg/min which is transferred as a slurry to a second reaction zone having a hydrogen to ethylene molar ratio in the vapor phase of from about 0.000001:1 to about 0.003:1 to produce polyethylene with a bimodal molecular weight distribution, a density of from about 0.91 to about 0.94 g/cm 3 , and a melt index of from about 0.10 to about 0.80 dg/min, wherein each of said melt indices is measured according to ASTM D1238, Condition 190/2.16.