US Patent 7968659 Copolymers and films thereof

Copolymers of ethylene and an alpha-olefin having (a) a density in the range 0.900-0.940 g/cm3, (b) a molecular weight distribution (Mw/Mn) in the range 3.5 to 4.5, (c) a melt elastic modulus G′ (G″=500 Pa) in the range 40 to 150 Pa, (d) an activation energy of flow (Ea) in the range 28-45 kJ/mol, and (e) a melt index (g/10 ml) in the range 1.0-3.5. The copolymers are suitably prepared in the gas phase by use of a supported metallocene catalyst system. The copolymers show improved processability and are particular suitable for use in blown film applications.