METHOD FOR PREPARING CHLORINATED BUTYL RUBBER Russian patent published in 2008 - IPC C08C19/12 C08F8/20 

FIELD: rubber industry, chemical technology.

SUBSTANCE: invention relates to chemical modifying rubbers, in particular, preparing halogenated butyl rubbers. Method for preparing chlorinated butyl rubber involves the following steps: mixing 3-5% butyl rubber aqueous dispersion with hydrocarbon solvent, dissolving butyl rubber at temperature 20-60°C, separation of aqueous layer and interaction of butyl rubber solution of the concentration 10-15 wt.-% with tert.-butylhypochlorite taken in the amount 8 wt.-% per rubber. The process is carried out in one or some successive devices at temperature 10-50°C wherein neutralization of tert.-butylhypochlorite excess is carried out with sodium sulfite and sodium hydroxide aqueous solutions up to the complete decomposition of tert.-butylhypochlorite and pH value 2-3 in aqueous phase. Then method involves separation of phases, washing out rubber solution with water for one or some steps, additional treatment of chlorinated butyl rubber solution with sodium hydroxide solution to pH value 7-8 in aqueous extract, isolation of rubber by aqueous degassing, drying and briquetting. Invention provides improving the process for preparing chlorinated butyl rubber at steps of neutralization of chlorinated agent excess and washing out polymer solution from neutralization products, improving separation of hydrocarbon and aqueous phases and decreasing content of mineral substances in the end product.

EFFECT: improved preparing method.

2 cl, 1 tbl, 1 dwg, 10 ex