METHOD FOR STOPPING RADICAL POLYMERIZATION IN THE SYNTHESIS OF EMULSION BUTADIENE-STYRENE RUBBERS Russian patent published in 2022 - IPC C08F2/22 C08F2/42 C08F36/06 

FIELD: petrochemical industry.

SUBSTANCE: invention relates to the petrochemical industry, in particular to the production of styrene-butadiene rubbers obtained by emulsion polymerization. A method for stopping emulsion polymerization initiated by free radicals in the synthesis of emulsion butadiene-styrene rubbers is described, including the addition of an isopropyl hydroxylamine stopper to latex heated to a temperature no lower than 30°C in a mixture with a dispersant in a mass ratio of 1.0:(0.5÷1.0) in an amount no lower than 0.02 wt. % of isopropylhydroxylamine per 100 wt. % of monomers. A method for producing low-temperature emulsion styrene-butadiene rubber using the specified method for stopping emulsion polymerization and styrene-butadiene rubber are also described.

EFFECT: reduction in the formation of coagulum in latex, especially at a high degassing temperature, an increase in the degree of decomposition of hydroperoxide (polymerization initiator) by heating latex with a stopper in the maturing tank to a temperature no lower than 30°C, a reduction in steam consumption for degassing by preheating latex in the maturing tank, for example, steam condensate, reduction to a minimum of the formation of polystyrene and polybutadiene in the distillation columns, an increase in the working time of the columns due to reduced clogging with polymer.

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