US Patent 8673437 Films having improved mechanical properties

A blown film having a thickness from 8 to 200 μm and dart drop impact DDI of more than 400 g, comprising a polyethylene molding composition having a multimodal molar mass distribution; a density from 0.940 to 0.948 g/cm3; an MFR190/5, from 0.10 to 0.50 dg/min; comprising:40 to 60% of an ethylene homopolymer A having a molecular weight;25 to 45% of a copolymer B of ethylene and at least one comonomer selected from the group of olefins having from 4 to 8 carbon atoms, said copolymer B having a molecular weight higher than said molecular weight of homopolymer A; and10 to 30% of a copolymer C of ethylene and at least one comonomer, said copolymer C having a molecular weight higher than said molecular weight of copolymer B,all percentages being based on the total weight of the molding composition.