METHOD OF PREPARING BLOCK COPOLYMERIC COMPOSITION, AND BLOCK COPOLYMERIC COMPOSITION Russian patent published in 1998 - IPC

FIELD: adhesive compositions. SUBSTANCE: present invention describes method of preparing block copolymeric compositions which comprises two consecutive stages (1) polymerization of aromatic vinyl monomer in inert hydrocarbon solvent in the presence of organolithium initiator, said polymerization being carried out till complete conversion of monomer; (2) addition of diene monomer having conjugated double bonds to polymerization mixture, and polymerization of said diene monomer is carried out till substantially complete conversion of said monomer; (3) addition of second portion of organolithium initiator and subsequent addition of second portion of diene monomer having conjugated double bonds, and polymerization of said diene monomer is carried out till its substantially complete conversion; (4) addition of second portion of aromatic vinyl monomer, and polymerization of said aromatic vinyl monomer is carried out till its substantially complete conversion; (5) addition of chain termination agent. Besides, block copolymeric composition comprises (I) triblock copolymer A-B-$$$ having two different or same end polymer blocks A and $$$ from aromatic vinyl monomer, and one middle polymer block $$$ from diene monomer having conjugated double bonds; and II diblock copolymer $$$ having one polymer block $$$ from diene monomer having conjugated double bonds, and one polymer block $$$ from aromatic vinyl monomer where molar weight of $$$ (triblock)/$$$ (diblock) copolymer is from 0.9 to 1.1 where both block copolymers are obtained by consecutive polymerization and where the content of aromatic vinyl compound in triblock copolymer and also in diblock copolymer is 55 wt % or less of total weight of triblock copolymer and diblock copolymer respectively. The claimed composition is elastic and is obtained in one stage without using mixing equipment. EFFECT: more efficient preparation method. 6 cl, 3 tbl