METHOD FOR PREPARING CARBOXYMETHYLCELLULOSE SODIUM SALT Russian patent published in 2004 - IPC

FIELD: high-molecular compounds. SUBSTANCE: invention relates to preparing cellulose ether, namely, carboxymethylcellulose sodium salt that is used widely in petroleum-extracting and gas production, building, pharmaceutical, food and other branched of industry. Method is carried out by initial cellulose activation by hydropulping for 20-120 min at 30-40 C to form suspension in the concentration 0.1-2.5 wt.-% followed by condensing and squeezing out up to the liquid phase content 40-56 wt.-%. Prepared mass is stirred up. Then by cellulose dosing the latter is stirred partially with monochloroacetic acid sodium salt and prepared mixture and sodium hydroxide solution are fed to dual- screw machine with intense stirring for 1-2 min at the rate of reaction mass shift from 500 to 3 000 s^-1 and at temperature 65 C, not above, with simultaneous addition of high-molecular polyether based on ethylene oxide or propylene oxide as an aqueous solution in the concentration 25-50 wt.-%. Prepared product is dried in convective-contact regimen for 40-60 min at temperature 70 C, not above, followed by crushing. Invention provides the development of continuous manufacturing process with wasteless preparing method practically and high degree of ecology safety. The sequence of stages and regimens in carboxymethylation process allows widely using sort assortment of celluloses. EFFECT: improved preparing method. 2 tbl, 16 ex