Patent ID: 8202940
Filing Date: 2012-06-19
Classification: B29B,B29C,B29K,C08L

Abstract:
1. A method for making a bimodal polyethylene composition, comprising: polymerizing ethylene and a comonomer in the presence of a mixed catalyst comprising at least one Group-15 containing catalyst in a gas phase polymerization reactor to produce a bimodal polyethylene; heating the bimodal polyethylene to produce a substantially melted bimodal polyethylene; contacting the substantially melted bimodal polyethylene with a gas mixture comprising from about 8 vol % to about 20 vol % oxygen to produce an oxygen tailored bimodal polyethylene, wherein during the oxygen tailoring the amount of phosphorous containing compounds present is less than 0.05 wt % based on the combined weight of the polyethylene resin and phosphorous containing compounds; and cooling the oxygen tailored bimodal polyethylene to produce a bimodal polyethylene composition comprising: a percent die swell of less than about 80%.