Blend of high-molecular-weight polypropylene and high-molecular weight ethylene-propylene copolymer with broad molecular weight distribution

A two-step polymerization process for preparing a propylene-ethylene blend by copolymerization of propylene and ethylene in a liquid propylene medium in a first step preceded by prepolymerization and polymerization of propylene or in a liquid propylene medium copolymerization with another 1-olefin having from 4 to 20 carbon atoms, in suspension and at a temperature in the range from 30 to 1500.degree. C., and a pressure of from 10 to 100 bar, and with a reaction time of from 30 min to 6 h, in the presence of a catalyst, of an organoaluminum compound (B) and of an organosilicon compound (C), in a second step, wherein, in the first step, the suspension medium is also the monomer, and an ethylene-propylene copolymer is prepared in the first step having a viscosity of from 500 to 1400 ml/g and forms a proportion of from 20 to 80% of the entire polymer, and wherein, after the second reaction step, the entire polymer has a viscosity of from 200 to 400 ml/g of a polydispersity M.sub.w /M.sub.n of from 6 to 20.