METHOD FOR PRODUCING BUTADIENE-NITRILE RUBBER Russian patent published in 2023 - IPC C08F236/12 C08C3/02 

FIELD: production of butadiene-nitrile rubber (BNR).

SUBSTANCE: The invention describes a method for producing butadiene-nitrile rubber (BNR) by emulsion copolymerization of butadiene and acrylic acid nitrile (AAN) in the presence of emulsifiers based on rosin and fatty acids with subsequent stages of polymerization stoppering, distillation of unreacted monomers, latex coagulation and rubber drying, characterized in that a mixture of polymerization stopper is introduced into BNR latex after polymerization diethylhydroxylamine and polysiloxane defoamer "Penta-475", taken in a mass ratio of 1:0.5 and a total amount of 0.08-0.12 wt.h. and 0.04-0.06 wt.h. per 100 wt.h. polymer, respectively, supplied in four doses: 1) 50% by weight (of the total amount of the mixture) - into the maturing apparatus after reaching 70-80% conversion of monomers, 2) 20% by weight - into the pre-degassing column, 3) 10% by weight - into the first vacuum degassing column and 4) 20% by weight - into the countercurrent degassing column, and an inhibitor p-methoxyphenol in the amount of 0.005-0.01 wt.h. per 100 wt.h is injected into the distilled AAN before it is steamed from water. AAN.

EFFECT: The present invention enables to increase the aggregate stability of latex during distillation of unreacted monomers from it; reduction of latex foaming, prevention of its losses and ingress into capacitors; inhibition of butadiene copolymerization in degassing columns; prevention of homopolymerization of AAN when it is steamed from water; increase the run time of distillation units. 1 cl, 1 tbl, 6 ex