METHOD OF PRODUCING OLEFIN POLYMERS AND COPOLYMERS Russian patent published in 1998 - IPC

FIELD: polymerization processes. SUBSTANCE: gas-phase polymerization of olefins with general formula CH₂=CHR, where R is hydrogen, alkyl, or aryl with up to 8 carbon atoms, is carried out in one or several reactors with fluidized or mechanically stirred catalyst bed. Catalyst involved is prepared by reaction of titanium halide or titanium halogen-alcoholate and, optionally, an electronodonor compound applied on activated magnesium dihalide with trialkylaluminum compound and, optionally, electronodonor compound. Method includes following stages: (a) contact of catalytic components in presence of olefin; (b) prepolymerization of propylene or its mixtures with small amounts of ethylene or CH₂=CHR-olefin to form polypropylene with xylene-insolubility percentage at least 66 wt.-% in amount from 0.5 to 1000 g per 1 g of solid catalytic component; and (c) gas-phase polymerization of one or several olefins with above-indicated general formula in presence of prepolymer-catalyst system obtained in stage (b), while simultaneously maintaining in gas phase alkane to olefin molar ratio from 2:8 to 8:2. EFFECT: increased reliability of polymerization process with high specific productivity and/or polymer quality. 10 cl, 1 dwg