GB562581A - Alkali-soluble carboxyethyl cellulose ether - Google Patents

Abstract

A water-insoluble, alkali-soluble carboxyethyl cellulose ether is produced by mixing cellulose with a solution containing about 15-40 per cent of a strongly basic, water-soluble hydroxide in an amount at least molecularly proportional to the glucose units of the cellulose, and about 0.2-0.5 molecular proportions of acrylonitrile per glucose unit of the cellulose, and allowing the reaction to proceed within the temperature range of 5-35 DEG C. The reaction is continued until the reaction mixture is dispersible in a 5-10 per cent solution of a strongly basic hydroxide to form a substantially homogeneous solution or paste. The cellulosic material may be cotton, regenerated cellulose, cellulose bast fibre, or wood pulp from which resin, lignin, and other impurities have been removed. The alkali may be caustic soda or potash or a strongly basic quaternary ammonium hydroxide, e.g. benzyl trimethyl or dibenzyl dimethyl or fetraethyl ammonium hydroxide. In an example, wood pulp is treated with a solution of 30 per cent caustic soda in a mechanical mixer. Acrylo-nitrile is added and mixing is continued for several hours. The product is dissolved in 5 per cent caustic soda solution. The cellulose ether is precipitated by adding acid. It is washed and then redissolved in p caustic soda solution. The cellulose ether may be dissolved in a solution of trimethyl benzyl ammonium hydroxide and sodium hydroxide and used to impregnate a piece of cotton sheeting which is then squeezed, acidified with a solution of sulphuric acid and sodium sulphate, rinsed and dried. The cloth is stiffened and the effect is retained after laundering with soap and soda solutions. The cellulose ethers obtained by the process may be used as thickening agents, protective colloids, sizing and finishing agents for textiles, and their solutions may be extruded to form filaments and films, coagulation being effected in acid media.