METHOD FOR CONTROLLING THE MOLECULAR WEIGHT OF A POLYMER DURING THE SYNTHESIS OF RUBBERS BY THE METHOD OF EMULSION POLYMERIZATION Russian patent published in 2021 - IPC C08F236/10 C08F236/12 C08F2/24 

FIELD: molecular weight controlling.

SUBSTANCE: invention relates to a method for controlling the molecular weight of rubbers obtained by the method for emulsion polymerization. A method is proposed that includes the introduction of an aliphatic mercaptan microemulsified in an aqueous solution of an emulsifier - potassium soap rosin - in the presence of a co-emulsifier, characterized in that 70-80% of the total amount of aliphatic mercaptan is supplied before the start of the process in the form of a solution in a monomer and 20-30 % of the total amount of aliphatic mercaptan - during polymerization in the form of a microemulsion containing ethylene glycol monobutyl ether (butyl cellosolve) as a co-emulsifier, taken in a mass ratio emulsifier: aliphatic mercaptan: butyl cellosolve: water equal to 1.0:0.1:(0.05-0.1):(8.8-8.85). Microemulsion of aliphatic mercaptan is introduced during polymerization in the range of monomer conversion of 30-60% in 1-3 steps.

EFFECT: increasing the efficiency of regulating the molecular weight of polymers obtained at high conversions of monomers (65-75%), without reducing the solubility of rubbers and maintaining the aggregate stability of latexes to mechanical and thermomechanical influences.

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