GB323019A - Improvements in the manufacture of nitro-cellulose - Google Patents

Abstract

323,019. Moulton, H. F., and Tschudin, E. June 16, 1928. Divided on 322,998. Cellulose nitrates and xanthates.-Wood pulp is stirred up with 70 per cent of water, treated with about 10-15 per cent of caustic soda and then with 5-10 per cent of carbon bisulphide to form a gelatinous paste, which can be pressed through dies into continuous strings and subsequently cut into pellets or alternatively extruded directly in the form of short pellets. The strings or pellets are immersed in a hardensolution, for example an acid or acid salt solution, washed and dried, but if desired they may be immersed in a glycerine bath before drying. The pellets in an air dried state are then nitrated preferably in a centrifugal nitrator. A nitration mixture may be used in which the proportions differ substantially from those ordinarily used, for example, a mixture comprising 81 per cent of nitric acid, 16 per cent of sulphuric acid and 3 per cent of water. Alternatively, the material may be nitrated in the form of strings, which can be subsequently divided into pellets. The material is freed from the nitration mixture, preferably bv means of a centrifuge, washed with water, and stabilized by boiling. The Provisional Specification refers to the employmeent of soda lye of 30-36 BÚ. in quantity amounting to 80 per cent on the weight of cellulose and 20 per cent by weight of carbon di-sulphide for gelatinizing the wood pulp.