FIELD: chemical or physical processes.
SUBSTANCE: invention relates to an improved catalyst system for producing polymers and a method of using the catalyst system for producing olefin polymers, such as polypropylene polymers, polyethylene polymers, their copolymers and their ternary copolymers. Described is a method of producing olefin polymers, comprising polymerising an olefin in the presence of a Ziegler–Natta catalyst system in a gas-phase polymerisation reactor, wherein the Ziegler–Natta catalyst system comprises: a solid catalyst component; selectivity control agent; and an activity limiting agent; solid catalyst component contains: a magnesium functional group; functional group of titanium; and internal electron donor; selectivity control agent contains silane with structural formula, where R1 is a C1-C6 alkyl group, and R2 is a branched C3-C8 alkyl group; and method involves obtaining propylene homopolymer, having a bulk density of more than 0.38 g/cm3 and less than 1% by weight of particles having a size of less than 120 mesh (125 mcm); in the method a propylene and ethylene copolymer is obtained, having a bulk density of more than 0.38 g/cm3 and less than 1% by weight of particles having a size of less than 120 mesh (125 mcm); or in the method a ternary copolymer is obtained, having a bulk density of more than 0.38 g/cm3 and less than 1% by weight of particles having a size of less than 120 mesh (125 mcm).
EFFECT: obtaining polymers with higher bulk density and significantly reduced content of fine particles, as well as obtaining olefin polymers with a higher rate, which provides easy handling and reduced probability of equipment clogging.
18 cl, 2 dwg
