| abstract |
Polymodal (esp. dimodal) ethylene (co)polymers are made by solution or dispersion polymerisation of ethylene (opt. together with other monomers, such as propylene, butene-1, isobutene, butadiene, etc.), by a two- or multi-stage process in which different amts. of hydrogen are present during the different stages. Ethylene (co)polymers contng. high and low mol. fractions, (one fraction of mol. wt. 8,000-80,000 and another of mol. wt. over 150,000) having improved flow properties, better extrusion qualities and less tendency to stress cracking in use. |