MULTI-STEP ETHYLENE POLYMERISATION METHOD Russian patent published in 2014 - IPC C08F2/18 C08F4/02 C08F4/654 C08F10/02 

FIELD: chemistry.

SUBSTANCE: invention relates to a suspension method of producing an ethylene polymer having a melt flow ratio F/P greater than 25. The method is carried out in two or more polymerisation steps at temperature of 60-120°C. At least two of the two or more polymerisation steps are carried out at different concentration of a chain-terminating agent. The method is carried out in the presence of a catalyst system containing a product obtained by contacting a solid catalyst component and an organoaluminium compound. The solid component contains Ti, Mg and halogen and has porosity (P_F) measured by a mercury method, and owing to the presence of pores with a radius equal to or less than 1 mcm, of at least 0.3 cm³/g, and surface area of less than 100 m²/g. Particles of the solid component have a spherical morphology and average diameter of 8-35 mcm.

EFFECT: obtaining a polymer with a wider molecular weight distribution, good mechanical properties without or with minimal problems associated with homogeneity while maintaining good polymerisation activity.

9 cl, 2 tbl, 2 ex