SYSTEMS AND METHODS OF PRODUCING POLYMERS Russian patent published in 2014 - IPC C08F2/00 C08F2/34 C08F4/22 C08F10/00 

FIELD: chemistry.

SUBSTANCE: described is a method of reducing change in flow index for all grain-size classes of polyolefin particles. The method includes feeding a chromium oxide-based catalyst into a gaseous reactor system to react with a gaseous monomer to obtain a polyolefin; adding alkylaluminium alkoxide into the reactor system in situ in an effective amount which is sufficient to reduce molecular weight of the polyolefin to a given value; and further measuring the flow index or melt index of the polyolefin. The polyolefin is characterised by change in flow index of no more than 3.5 times for all grain-size classes collected on sieves 18, 35 and 60 US mesh from a full set of sieves with size of 10, 18, 35, 60, 120, 200 US mesh. Also described is a polymerisation reactor system.

EFFECT: providing a polyolefin obtained using a chromium oxide-based catalyst, where the polyolefin has a considerably smaller change in flow index for all grain-size classes of particles.

16 cl, 3 dwg, 1 tbl, 14 ex