Patent GB-507137-A (GB)
Title: Process for the manufacture of cellulose derivatives and of treating fibrous materials therewith
IPC: C08B11/20
Filed: 1937-09-07
Abstract: 507,137. Cellulose ethers and xanthates; treating textiles. LILIENFELD, L. Sept. 7, 1937, No. 24415. [Classes 2 (ii) and 15 (ii)] Cellulose ethers which are wholly or partially soluble in caustic alkali solution and insoluble or sparingly soluble in water and are incapable of forming films, or are incapable of forming films of practical value, are prepared by treating an alkali soluble alkyl, hydroxy-alkyl or hydroxy-acid cellulose ether or a cellulose ether obtained from halogen-olefines, with a hydrolysing or degrading and /or oxidizing agent until the desired product is obtained. The end-. point of the treatment is determined by taking test samples, which are washed in water, dissolved in 7-10 per cent caustic soda solution, spread on to a glass plate and immersed in a coagulating bath. When the solution does not yield a coherent film in the bath or in the wash liquor or on drying, or yields a film which falls to pieces at any stage of the operation, the end point is reached. When a far-going degradation is aimedat, the physical condition of the washed and dried product may serve as a guide. If the cellulose ether can be easily pulverized, the treatment can be regarded as finished. , The following treatments are referred to: (1) treatment with excess of dilute mineral acid in the cold ; (2) with excess of dilute mineral acid at raised temperature ; (3) with excess of dilute mineral acid followed by removal of the excess and leaving the material to stand in the air ; (4),with strong sulphuric acid of a concentration incapable of dissolving the cellulose ether ; (5) with strong hydrochloric acid; (6) with gaseous hydrochloric acid in presence of a small amount of water; (7) with alkali in presence of a small proportion of chlorine; (8) with chlorine or bromine in presence of water; and (9) with strong organic acid, e.g. glacial acetic acid containing chlorine or bromine. Suitable oxidizing agents specified are. (1) chloride of lime; (2)'hypochlorous acid or an alkali metal hypochlorite; (3) solution of bromine or chlorine in water ; (4) chlorine in presence of sunlight and water; (5) potassium permanganate in presence or absence of alkali; (6) nitric acid; (7) chromic acid; (8) caustic soda in presence of oxygen; and (9) hydrogen peroxide, alkali peroxide or ozone. The product obtained may be xanthated, for example according to the processes described in Specifications 335,993, 335,994, [both in Class 2 (ii)], 357,167, 357,527, 357,595, 367,920, 368,288, 459,122, 459,123, 459,124, 462,283, 462,456, 462,712, 462,713, 472,888, and 472,933. The product, or the xanthated product, in the form of a solution or paste may be applied to a fibrous material, e.g. a textile material, if desired together with other finishing, impregnating, dressing, coating, filling, weighting, printing or sizing agents. When the product is applied from solution it may be further treated with a precipitating or coagulating agent, e.g. water or a solution of an' alkali carbonate. Textile materials treated by the process are not impaired as regards their feel and appearance even in the absence of softening agents or when applied in large amounts. In an example, a cellulose ether prepared according to any one of Specifications 177,810, 200,816, 200,834, 203,346, 203,347, 231,807, 231,808, 231,809, 231,810, 231,811, 335,994, [all in Class 2 (ii)], 356,776, 357,167, 357,595, 367,920, 368,288, 374,964, 390,519, 457,031, 459,122, 469,123, 459,124, 462,283, 462,456, 462,712, 462,713, 470,746, 474,223, 491,488 or 503,830 is mixed with hydrochloric acid of 0À5 per cent strength and heated to 50-100‹ C. The product is dissolved in caustic soda solution at from--5 to -10‹ C., applied to a woven fabric, and coagulated in a precipitating bath. Other examples illustrate the use of hydrochloric acid of 0À05, 0À1, 0À2, 1 and 2 per cent, and of sulphuric acid. Other examples show the use of chloride of lime, and of alkaline and neutral potassium permanganate in the process. Specifications 212,864, [Class 2 (ii)], 390,517, 479,445, and 490,510 also are referred to.