PREPARATION OF MULTIMODAL POLYETHYLENE

摘要

Disclosed is a polyethylene composition. The composition comprises single-site multimodal resin A and single-site multimodal resin B, wherein resin A differs from resin B in molecular weight, in monomeric composition, in density, in long chain branch concentration or distribution, or in combinations thereof. Disclosed is also a method for making the polyethylene composition. The method comprises polymerizing, in the presence of two or more single-site catalysts, ethylene or its mixture with a C3-C10 a-olefin to form a first multimodal resin and continuing the polymerization in the presence of the same catalysts but in a different hydrogen concentration, in a different monomer composition, or at a different temperature to form a second multimodal resin.