IN-SITU POLYMER MIXTURE FOR TIRES Russian patent published in 2022 - IPC C08C19/25 C08C19/44 C08F236/04 C08F236/06 C08F236/10 C08F297/02 C08F297/04 C08L53/02 B60C1/00 

FIELD: chemistry.

SUBSTANCE: group of inventions relates to a method for the production of a synthetic rubber mixture containing high-molecular polydiene (A) and low-molecular polydiene (B), as well as to a synthetic rubber mixture, which can be obtained in accordance with the method, to rubber compositions containing the specified mixture, to a method for the production of a cross-linked rubber composition, to a cured rubber composition, and to products, such as tires, conveyor belts, seals, and hoses. The method for the production of a synthetic rubber mixture includes a stage of polymerization of at least one conjugated diene monomer and one or more alpha-olefin monomers, including aromatic vinyl monomers, in the presence of one or more polymerization initiators and a polar agent in an organic solvent. Moreover, the stage of polymerization of at least one conjugated diene monomer and one or more alpha-olefin monomers, including aromatic vinyl monomers, includes stages (i), (ii), and (iii). At the first stage (i), a solvent, the first part of at least one conjugated diene monomer, and the first part of one or more polymerization initiators are provided, where the polymerization initiator contains an organolithium compound and the first part of one or more alpha-olefin monomers, including aromatic vinyl monomers, and the first part of a polar agent, and at least one conjugated diene monomer and one or more alpha-olefin monomers are polymerized to a degree of conversion of at least 95% to obtain a mixture containing live high-molecular polydiene polymer or copolymer. At the second stage (ii), the second part of the specified polymerization initiator is added to the mixture obtained at the stage (i), as well as the second part of at least one conjugated diene monomer and optionally one or more alpha-olefin monomers, including aromatic vinyl monomers, as well as, optionally, the polar agent, and polymerized to obtain a mixture containing high-molecular polydiene (A) and low-molecular polydiene (B). At the same time, high-molecular polydiene (A) has an average molecular weight (Mw) of 500-3000 kg/mol, and low-molecular polydiene (B) has an average molecular weight (Mw) of 0.5-100 kg/mol. At the third stage (iii), at least one compound is added to the mixture obtained at the stage (ii) to modify an end of a chain to obtain a mixture containing high-molecular polydiene (A) with a modified end of the chain and low-molecular polydiene (B) with a modified end of the chain.

EFFECT: provision of a method for the production of a synthetic rubber mixture containing high-molecular polydiene (A) with a modified end of a chain and low-molecular polydiene (B) with a modified end of a chain, characterized by particularly high properties, since they provide the possibility of obtaining products, such as tires with reduced heat build-up (HBU) of a cross-linked polymer composition, improved rolling resistance and improved dry surface grip/snow grip, as well as improved characteristics of wet surface grip-snow grip.

15 cl, 2 tbl, 9 ex