HIGH-FLUIDITY PROPYLENE BLOCK COPOLYMERS Russian patent published in 2006 - IPC C08F297/08 C08F210/06 C08J5/18 D01F6/04 

FIELD: polymer production.

SUBSTANCE: invention relates to high-fluidity propylene block copolymers consisting of propylene homopolymer (50-80%) and propylene copolymer, in which propylene is copolymerized with 10-70% of other than propylene C²-C⁸-alk-1-ene, (20-50%). Process cos4 gas-phase two-stage polymerization in presence of Ziegler-Natta catalyst. In the first polymerization stage, propylene is polymerized at pressure 10 to 50 bar, temperature 50 to 100°C, and average reaction time 0.3 to 5 h in presence of at least 2.0 vol % of hydrogen based on total volume. Thus obtained propylene homopolymer is sent along with Ziegler-Natta catalyst system to intermediate vessel, wherein first pressure is lowered for 0.01 to 5 min to below 5 bar at temperature 10 to 80°C and then gas mixture is compressed to raise pressure to 5-60 bar. Propylene homopolymer subjected to intermediate decompression in intermediate vessel is then sent along with Ziegler-Natta catalyst system to the second polymerization stage, wherein, at pressure 10 to 50 bar, temperature 50 to 100°C, and average reaction time 0.5 to 5 h, propylene homopolymer is copolymerized with propylene/C²-C⁸-alk-1-ene mixture. Weight ratio of first-stage and second-stage reacted monomers is maintained between 4:1 and 1:1. High-fluidity propylene block copolymers are useful in manufacture of films, fibers, and molded products.

EFFECT: optimized process conditions.

3 cl, 5 tbl