Patent ID: 8378043

Claim:
A process to produce an ethylene alpha-olefin copolymer, the process comprising: contacting ethylene and at least one alpha-olefin with a metallocene catalyst in at least one gas phase reactor at a reactor pressure of from 0.7 to 70 bar and a reactor temperature of from 20° C. to 150° C. to form an ethylene alpha-olefin copolymer, wherein the ethylene alpha-olefin copolymer satisfies the following conditions: a density of 0.927 g/cc or greater, a melt index ratio of (I 21 /I 2 ) of from 15 to 40, an ESCR value of 500 hr or greater when measured according to ASTM 1693/B in 10% Igepal, a T 75 -T 25 value of 4 or greater wherein T 25 is the temperature at which 25% of the eluted polymer is obtained and T 75 is the temperature at which 75% of the eluted polymer is obtained in a TREF experiment, and a F 80 value of 10% or greater, wherein F 80 is the fraction of polymer that elutes below 80° C., and wherein the metallocene catalyst is selected from the group consisting of: bis(n-propylcyclopentadienyl)hafnium X n , bis(n-butylcyclopentadienyl)hafnium X n , bis(n-pentylcyclopentadienyl)hafnium X n , (n-propyl cyclopentadienyl)(n-butylcyclopentadienyl)hafnium X n , bis[(2-trimethylsilylethyl)cyclopentadienyl]hafnium X n , bis(trimethylsilyl cyclopentadienyl)hafnium X n , dimethylsilylbis(n-propylcyclopentadienyl)hafnium X n , dimethylsilylbis(n-butylcyclopentadienyl)hafnium X n , bis(1-n-propyl-2-methylcyclopentadienyl)hafnium X n , and (n-propylcyclopentadienyl)(1-n-propyl-3-n-butylcyclopentadienyl)hafnium X n ; wherein X n is selected from the consisting of halogen ions, hydrides, C 1-12 alkyls, C 2-12 alkenyls, C 6-12 aryls, C 7-20 alkylaryls, C 1-12 alkoxys, C 6-16 aryloxys, C 7-18 alkylaryloxys, C 1-12 fluoroalkyls, C 6-12 fluoroaryls, and C 1-12 heteroatom-containing hydrocarbons and substituted derivatives thereof.