METHOD FOR PREPARING METHYLCELLULOSE-BASE COMPOSITION Russian patent published in 2003 - IPC

FIELD: chemical technology. SUBSTANCE: invention relates to method for preparing compositions based on cellulose ether, i. e. methylcellulose. Method involves preparing alkaline cellulose and its methylation. After methylation the prepared reaction mass is suspended in an aqueous medium containing glyoxal and acid salt of alkaline metal and phosphoric acid providing pH value of suspension from 3.2 to 3.8, cross-linkage with glyoxal adding in the amount 0.05-0.20 mole per anhydroglucose cellulose link in an aqueous medium, in the presence of agent for pH value control, at hydromodulus = (5-10):1 and temperature 30-60 C for 30-60 min. Then to reaction mixture alkaline metal hydroxide is added and neutralization is carried out up to pH value 7.5-8.0 followed by squeezing out methylcellulose-base composition at temperature 80-95 C and its drying. Invention provides increasing the dissolving rate of composition in cold water and retaining the polymerization degree of methylcellulose. Viscosity of the composition aqueous solutions remains at level of viscosity of methylcellulose aqueous solution without cross-linkage with glyoxal. Invention provides reducing loss of composition in process it preparing at washing out stage. Composition can be used as emulsifying agents, thickening agents, dispersing and stabilizing agents, in building, chemical, oil and gas production industry. EFFECT: improved preparing method, valuable properties of composition. 1 tbl, 4 ex