BIMODAL POLYETHYLENE COPOLYMER AND FILM MADE OF IT Russian patent published in 2023 - IPC C08F210/16 C08F4/659 C08J5/18 B29C48/18 

FIELD: synthesis of copolymers.

SUBSTANCE: invention relates to methods for the synthesis of copolymers of propylene and ethylene, namely, describes a method for the synthesis of a bimodal ethylene-co-1-hexene copolymer consisting essentially of a higher molecular weight (HMW) and lower molecular weight (LMW) component. The copolymer is characterized at 190°C by melt elasticity (G′/G″ at 0.1 rad/s) from 0.5 to 0.8 Pa, high-load melt index from 7.0 to 11.0 g/10 minutes, MFR5 from 22.0 to 35.0, density from 0.9410 to 0.9550 g/cm³. The copolymerization of ethylene and 1-hexene is carried out using a catalytic system and an auxiliary catalyst in the presence of molecular gaseous hydrogen (H₂) and optionally an inducible condensing agent (ICA). Moreover, the bimodal catalytic system was obtained by bringing the first activator into contact with zirconium dibenzyl-bis(2-(pentamethylphenylamido)ethyl)amine and bis(butylcyclopentadienyl)zirconium dihalide; wherein the auxiliary catalyst is obtained by bringing the second activator into contact with a dialkyl bis(butylcyclopentadienyl)zirconium. Effective polymerization conditions are: reaction temperature from 80 to 110°C, molar ratio of molecular gaseous hydrogen to ethylene from 0.001 to 0.020; the molar ratio of 1-hexene to ethylene is from 0.005 to 0.050.

EFFECT: these characteristics make it possible to obtain films based on a bimodal copolymer of ethylene and propylene, which have increased strength, tear resistance, and instantaneous impact strength.

6 cl, 5 tbl, 7 ex