| 摘要 |
1,130,484. Cellulose solutions. RAYONIER Inc. 16 Feb., 1966 [27 July, 1965], No. 6833/66. Heading C3A. A fibreless solution comprises cellulose, dimethyl sulphoxide, nitrogen dioxide and 0À2 to 1À0% by weight of water. The composition may comprise cellulose, 3 to 30% NO 2 , 0À2 to 1À0% water and the balance dimethyl sulphoxide, the ratio of the proportion of nitrogen dioxide to that of cellulose by weight in the mixture being within the range 1À7 to 2À3. The term " cellulose " is used in the specification to include cellulose itself, cellulose esters and cellulose ethers. The composition may comprise cellulose, 10 to 25% by weight of nitrogen dioxide, 0À2 to 1À0% by weight of water, and the balance dimethyl sulphoxide, the proportion of nitrogen dioxide to that of cellulose by weight being within the range 1À7 to 2À3. The solution may be formed by dissolving comminuted cellulose in a solution of 3 to 30% by weight of nitrogen dioxide in dimethyl sulphoxide, the cellulose and/or the solution of nitrogen dioxide in dimethyl sulphoxide containing such a proportion of water that the final solution contains 0À2 to 1À0% by weight of water. The solution of cellulose may be prepared at ambient temperature or at a temperature of 10‹ to 30‹ C. Two or more celluloses differing in intrinsic viscosity may be mixed together in such proportions as to provide a blended cellulose having an intrinsic viscosity of 2À0 to 2À5 and this blended cellulose used for the preparation of the solution. The cellulose may be precipitated from the solution by adding the solution to acetone, or to an aliphatic alcohol, ether or ester which precipitating liquid is miscible with the cellulose solution. The solution may be cast to form a film and the cellulose regenerated by washing the film with or the solution may be wet spun into water and the filaments thereby formed washed with water to form regenerated cellulose filaments. |
