Patent ID: 7132486

Claim:
A gas phase polymerization process for producind a substantially unblended polyethylene comprising combining ethylene and α-olefin in the presence of a polymerization catalyst under polymerization conditions, wherein the ethylene α-olefin copolymer so formed comprises: a density in the range of from 0.910–0.960 gm/cm3; wherein said copolymer has a melt index ratio I 21 /I 2 (MIR), as determined by ASTM D-1238 condition E, in the range of from 40–90, at an MI in the range of 0.1–15g/ 10 min; a melt strength (MS) in the range of from 7–20 cN; less than 10 weight percent of a separate, branched polymer; and a CDBI of greater than 60%; and a Mw/Mn of ≦4.5; wherein said polymerization catalyst includes catalysis by a mixed metallocene system comprising: a) a bridged bisindenyl zirconocene dichloride, wherein said indenyl is hydrogenated; and b) one of a bridged bisindenyl zirconocene dichloride, wherein said indenyl is unsaturated; or a bridged bisindenyl zirconocene dichloride, wherein the cyclopentadienyl ring is substituted with one or more substituents; wherein a) and b) are each separately supported on silica support; wherein said a) and b) are present in said gas phase polymerization process in a ratio of 90:10–10:90, or 80:20–20:80, or 75:25–25:75, or 60:40–40:60, or 50:50; and wherein said mixed metallocene system is activated by one of a methylalumoxane, modified methylalumoxane, or non-coordinating anious, or mixtures thereof.