GB521446A - Improvements in and relating to cellulose derivatives and to a process for producingthe same - Google Patents

Abstract

521,446. Cellulose ethers. REICHEL, F. H., and CORNWELL, R. T. K. Oct. 20, 938, No. 30417. [Class 2 (ii)] Cellulosic material dispersed or dissolved in an aqueous alkaline solution is etherified by adding to the dispersion or solution an etherifying agent and controlling the temperature so that it does not exceed 70‹C., the reaction being continued until a cellulose ether which is soluble at 0‹C. in aqueous sodium hydroxide solutions of 3 per cent. or less alkali concentration is obtained. The cellulosic material may be alkali cellulose or a low-etherified alkali-soluble cellulose ether which is soluble in sodium hydroxide solutions of more than 3 per cent. alkali concentration, e.g., 5 or 10 per cent. It may be a hydroxy alkyl cellulose ether. The starting material may be dispersed or dissolved in aqueous alkali solution of 5 to 10 per cent. strength. The alkali cellulose may be obtained from any natural form of cellulose or from a cellulose conversion product. It may be dissolved in 18 per cent. caustic soda by freezing and then thawing the mixture. The low-etherified cellulose ether may be an alkyl, hydroxy-alkyl, or mixed ether. The etherifying agent may be dimethyl sulphate, methyl sodium sulphate, ethyl chloride or bromide, an alkylene oxide or a halohydrin. The alkali may be sodium or potassium hydroxide, or an organic base such as dimethylamine or tri-benzyl methyl ammonium hydroxide. The etherifying agent may be added in solution or liquid form, and it may be added in small quantities over a period of several hours. The reaction should be stopped before the product is substantially soluble in water. Alkyl groups to the extent of 0.2 or hydroxyalkyl groups to the extent of 0.1 for each cellulose unit may be introduced. The products may be used in the production of artificial filaments, films, tubes, and other articles, or of adhesives, coatings, or sizes for textiles or paper, or as thickening. agents for pigments. They may be mixed with viscose, cuprammonium cellulose solutions, rubber latex, resins, gelatine, waxes, fats, or oils. Specifications 203,347 and 231,807, [both in Class 2 (ii)], are referred to.