METHOD FOR MAKING RANDOM BUTADIENE-ISOPRENE COPOLYMERS WITH A HIGH CONTENT OF CIS-1,4-LINKS Russian patent published in 2023 - IPC C08F236/06 C08F236/08 C08F36/06 C08F36/08 C08F4/52 C08F4/54 C08L9/00 C08K3/11 C08K3/13 

FIELD: polymers.

SUBSTANCE: present invention relates to a process for the preparation of a random styrene-butadiene copolymer having a high level of cis-1,4 units. A method is described for producing a random butadiene-isoprene copolymer characterized by a high content of cis-1,4 links of 92% or more, including the copolymerization of butadiene and isoprene in the presence of at least one organic solvent and a catalytic system obtained in situ and containing: (a₁) neodymium carboxylate which is soluble in said organic solvent and comprises a variable amount of water, the H₂ O/Nd molar ratio being between 0.001/1 and 0.50/1; (a₂) aluminium alkyl compound; and (a₃) an aluminium alkyl compound containing at least one halogen atom; wherein the molar ratio between the halogen present in the aluminium alkyl compound containing at least one halogen atom (a₃) and the neodymium carboxylate (a₁) is between 2.5/1 and 5.5/1. A random butadiene-isoprene copolymer is also described characterized by a high content of cis-1,4 links, obtained by the claimed method, a vulcanizable elastomeric composition suitable for tire treads or tire sidewalls, and a vulcanized product obtained by vulcanizing such an elastomeric composition.

EFFECT: providing a method for obtaining a random butadiene-isoprene copolymer characterized by a high content of cis-1,4 units of both monomers, i.e., butadiene and isoprene, a narrow molecular weight distribution and a certain index of isoprene randomization.

15 cl, 3 tbl, 14 ex