ETHYLENE-ALPHA-OLEFIN BLOCK OF COPOLYMERS AND METHOD OF PREPARING THEREOF Russian patent published in 2000 - IPC

FIELD: chemistry of polymers. SUBSTANCE: described is new block copolymer including A- block and B-block wherein A-block comprises predominantly ethylene polymer and further contains up to 10 mole % of nonconjugated dilene units and its melting temperature is at least 110 C; B-block comprises first polymer segment adjacent with point of connection of A-block with B-block and contains ethylene and α alpha-olefin, units, and intramolecular distribution of B-block composition is such that at least two fragments thereof are different in composition by at least 5 wt % of ethylene units, each of fragments having at least 5 wt % of B-block, and B-block comprises tip segment which is essentially polymer of ethylene and (C₃-C₈)-olefin. Content of ethylene units in tip segment is at least 60 mole % of total number of monomer units in tip segment, and tip segment and B-block melts at temperatures from 35 to 130 C. Also described is method of preparing block of copolymers. Combined block copolymers are used as thermoplastic elastomers having physical properties which are identical with those of vulcanized elastomers. They are also useful as addition agents for lubricant or liquid fuel, as component of plastic materials and adhesive melts. EFFECT: improved properties of ethylene-alpha-olefin block of copolymers and more efficient preparation method thereof. 21 cl, 4 dwg, 5 ex, 5 tbl