Polymer composition, a process for the production thereof and films prepared thereof

A process for producing polyethylene compositions comprising the steps of

• subjecting ethylene and, optionally, hydrogen and/or comonomers to polymerization or copolymerization reactions in a multistage polymerization sequence of successive polymerization stages,
• operating at least one polymerization stage essentially in the absence of hydrogen so as to prepare a high molecular weight polymer component,
• carrying out the polymerization reactions in the presence of a single-site catalyst, the active complex of which is a siloxy-substituted bis-indenyl zirconium dihalide or has the general formula
• (X1)(X2)Hf(Cp-R1)(Cp-R2), (I)
• wherein
• X1 and X2 are either same or different and are selected from a group containing halogen, methyl, benzyl, amido or hydrogen,
• Hf is hafnium,
• Cp is a cyclopentadienyl group, and
• R1 and R2 are either the same of different and are either linear or branched hydrocarbyl groups containing 1-10 carbon atoms,
• to form a polyethylene composition comprising
• a low molecular weight average component with MFR2 of at least 10 g/10 min and a density higher that the overall density of the composition,
• a high molecular weight average component,
• said polyethylene composition having a melt flow rate in the range MFR2=0.1-5.0 g/10 min and a density of 905-960 kg/m3.