METHOD OF PREPARING THICKENING ADDITION AGENT Russian patent published in 2001 - IPC

FIELD: chemistry of polymers. SUBSTANCE: described is method of preparing thickening addition agent by dissolving polyisobutylene in industrial oil. Method is carried out in two apparatuses. One of apparatuses is charged with polyisobutylene with molecular weight varying from 4000 to 30,000 provided that its content in oil varies from 20 to 50 wt %, oil is fed portionwise under constant stirring, each portion constituting 5-10 wt % of amount of oil being fed into apparatus with 2-hour interval between feeds, and second apparatus is charged with butyl rubber and/or ethylene-propylene rubber having Mooney viscosity from 20 to 60 convention units provided its content in oil varies from 10 to 25 wt % same oil is fed portionwise under content stirring at 90-150 C, each portion consisting 2-5 wt % of amount of oil being fed into apparatus with 4-hour interval between feeds; solutions resulting from two apparatus are then mixed, weight ratio of solution from first apparatus to solution from other apparatus ranging from 5:1 to 8:1. EFFECT: higher depolymerization resistance, thickening power, viscosity stability index and homogeneity of solution of the thickening addition agent during prolonged storage. 2 cl, 6 ex, 1 tbl