Patent ID: 7592403

Claim:
A process for preparing an ethylene polymer, which process comprises preparing said ethylene polymer in the presence of an olefin polymerization catalyst comprising an organic hafnium compound selected from the group consisting of ethylene bis(indenyl)dimethyl hafnium, ethylene bis(indenyl)diethyl hafnium, ethylene bis(indenyl)diphenyl hafnium, ethylene bis(indenyl)methyl hafnium monochloride, ethylene bis(indenyl)ethyl hafnium monochloride, ethylene bis(indenyl)methyl hafnium monobromide, ethylene bis(indenyl) hafnium dichloride, ethylene bis(indenyl)hafnium dibromide, ethylene bis(4,5,6,7-tetrahydro-1-indenyl)dimethyl hafnium, ethylene bis(4,5,6,7-tetrahydro-1indenyl)methyl hafnium monochloride, ethylene bis(4,5,6,7-tetrahydro-1-indenyl)hafnium dichloride, ethylene bis(4,5,6,7-tetrahydro-1-indenyl)hafnium dibromide, ethylene bis(4-methyl-1-indenyl)hafnium dichloride, ethylene bis(5-methyl-1-indenyl)hafnium dichloride, ethylene bis(6-methyl-1-indenyl)hafnium dichloride, ethylene bis(7-methyl-1-indenyl)hafnium dichloride, ethylene bis(5-methoxy-1-indenyl)hafnium dichloride, ethylene bis(2,3-dimethyl-1-indenyl)hafnium dichloride, ethylene bis(4,7-dimethyl-1-indenyl)hafnium dichloride and ethylene bis(4,7-dimethoxy-1-indenyl)hafnium dichloride, and an organic boron compound as indispensable components and under a polymerization temperature of 50 to 100° C., wherein the ethylene polymer has: (A) a density of from 0.930 to 0.970 g/cm 3 , (B) a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn), as measured by GPC, of from 1.2 to 10, and (C) a ratio (MFR 10 /MFR 2 ) of a melt flow rate (MFR 10 ) at 190° C. under a load of 10 Kg to a melt flow rate (MFR 2 ) at 190° C. under a load of 2.16 Kg of from 16.2 to 50.