US Patent 7427649 Polyethylene blow molding composition for producing small containers

The invention relates to a polyethylene composition with multi-modal molecular mass distribution, which is particularly suitable for blow molding of small containers with a volume in the range of from 200 to 5000 cm3 (=ml). The composition has a density in the range of from 0.955 to 0.960 g/cm3 at 23° C. and an MFR190/5 in the range from 0.8 to 1.6 dg/min. It composition from 45 to 55% by weight of a low-molecular-mass ethylene homopolymer A, from 20 to 35% by weight of a high-molecular-mass copolymer B made from ethylene and from another 1-olefin having from 4 to 8 carbon atoms, and from 20 to 30% by weight of an ultrahigh-molecular-mass ethylene copolymer C.