METHOD OF PREPARING BUTYL RUBBER Russian patent published in 1997 - IPC

FIELD: manufacture of synthetic rubbers, more particularly butyl rubber. SUBSTANCE: process is carried out by copolymerization of blend comprising isobutylene and isoprene monomers and hydrocarbon solvent. Copolymerization is carried out in the presence of organoaluminium catalyst. Some blend (in amount of 10-50) based on its total amount is treated with dry alkali, mixed with untreated stream, and total amount is directed for copolymerization. Treatment with alkali makes it possible to stabilize pH value of the blend aqueous extract and thus to regulate polymerization process. On completion of copolymerization, aqueous degassing is performed, polymer is recovered, and the resulting rubber is dried. The claimed method comprises treating hydrocarbon condensate distilled off during rubber degassing. Condensate is treated with aqueous alkali solution resulting from treatment of some hydrocarbon blend. EFFECT: more efficient manufacturing method. 1 dwg , 1 tbl