METHOD OF TRANSITIONING BETWEEN INCOMPATIBLE OLEFIN POLYMERISATION CATALYST SYSTEMS Russian patent published in 2013 - IPC C08F2/38 C08F2/34 C08F10/00 

FIELD: chemistry.

SUBSTANCE: described is a method of transitioning from a first to a second olefin polymerisation catalyst system in one reactor, where the first catalyst system is incompatible with the second catalyst system. The method comprises steps: a) stopping a first olefin polymerisation reaction carried in the presence of the first catalyst system by cutting supply of the first catalyst system into the reactor and deactivating the first catalyst system, or by cutting supply of the first catalyst system and lowering or raising temperature, pressure or monomer concentration in the reactor, or by combining said ways of stopping the reaction, and b) feeding the second catalyst system and conducting a second olefin polymerisation reaction in the presence of the second catalyst system comprising catalyst components (A) and (B) producing, respectively, a first and a second polyolefin fraction. The M_w of the first polyolefin fraction is less than the M_w of the second polyolefin fraction and the initial activity of catalyst component (A) exceeds the initial activity of catalyst component (B).

EFFECT: method provides efficient transitioning without the need to empty the reactor, considerably reduces the transitioning time needed to attain the desired quality of the multimodal polymer obtained using the second catalyst system, which enables to quickly switch production between two multimodal polymers, thereby reducing the cost of production.

13 cl, 3 tbl, 4 ex