FIELD: polymer production. SUBSTANCE: elastomeric ethylene/propylene copolymers are prepared in presence of catalytic system constituted by (i) vanadium-based catalyst as such or applied on inert carrier and (ii) alkylaluminum compound having general formula RnAlXm, in which R represents C1-C20-alkyl, X halogen, m+n=3, and m is integer from 0 to 2, in presence of activator . Process is carried out in two stages and is characterized by that, in the first stage, polymerization proceeds in presence of catalyst, cocatalyst, and optionally activator, at molar ratio of cocatalyst to vanadium from 5 to 500, to yield suspension of liquid-phase polymer, which, in the second stage, is completed by additional polymerization-capable monomers together with (a) additional activator to ensure molar ratio between activator and sum of optional first-stage activator and second-stage activator plus vanadium within a range of 4 to 50 and (b) additional cocatalyst to ensure ratio between second-stage cocatalyst and first-stage vanadium from 5 to 500. Polymerization is continued until at least 3000 g of polymer is produced per 1 g catalyst. EFFECT: enabled control of composition and molecular weight of each component to provide required characteristics, in particular controllable morphology, excellent elastomeric properties, and high interphase homogeneity within polymer particles. 11 cl, 1 dwg, 1 tbl, 7 ex
