Patent GB-536768-A (GB)
Title: Manufacture of cellulose derivatives containing sulphur and nitrogen
IPC: D01F2/06
Filed: 1939-11-24
Abstract: 536,768. Cellulose derivatives ; artificial silk, films &c.: dyeing processes. SOC. OF CHEMICAL INDUSTRY IN BASLE. Nov. 24, 1939, Nos. 30737 and 30738. Convention dates, Nov. 9, 1938 and June 7, 1939. [Classes 2 (ii) and 15 (ii)) Cellulose xanthate in solid form is subjected to the action of a halogenating agent in presence of an aqueous solution of ammonia or a primary alkyl or substituted alkyl amine or a salt thereof so as to produce a cellulose derivative containing sulphur and nitrogen. The re-action may be effected with or without maintenance of the original fibrous structure of the cellulose material, e.g. a cotton yarn may be converted into cellulose xanthate and then into a cellulose derivative containing nitrogen and sulphur with retention of its fibrous structure. The products have an affinity for acid and substanvive dyestuffs. If it is not desired to retain the original fibrous form, a solution of cellulose xanthate may be prepared and formed into filaments, staple fibre, films, or sheets which are then treated with the halogenating agent and ammonia or primary amine. The product may be derived from cotton linters, wood pulp, or regenerated cellulose. Ammonium chloride, sulphate, nitrate, phosphate, formate acetate, tartrate, citrate, or benzoate, or ammonia, or methylamine, ethylamine, ethylene diamine, ethyl ethylene diamine unsymmetrical diethyl ethylene diamine, oxyethylamine, ethoxyethylamine, or benzylamine, or a salt thereof, may be used as the nitrogensupplying reagent. The halogenating reagent may be chlorine, a hypochlorite, or a salt of p-toluene sulphonic acid chloramide or dichloramide. The treatment may be effected at room temperature.. The cellulose xanthate may be treated with an aqueous solution of the amine or ammonia at 40‹-60‹C. and with the halogenating agent at room temperature. Cellulose xanthate solutions may be extruded or otherwise shaped and co-agulated by means of a salt solution, e.g. an ammonium salt solution and in this case the treatment with halogenating agent may follow directly after the co-agulation. The coagulation bath may contain some sulphuric or acetic acid. The final product may be passed through a solution containing acid or sodium bi-sulphite in order to remove any residual halogen. The products have good affinity for acid and substantive dyes. In. an example, cotton yarn is impregnated with a solution of sodium hydroxide and carbonate and treated with carbon bi-sulphide. The yarn is then immersed in ammonium chloride solution, and sodium hypochlorite solution is then added. The yarn is rinsed, washed with bisulphite solution, rinsed and dried. In another example, cotton yarn, which has been xanthated and treated with ammonia or an ammonium salt and a hypochlorite, is dyed at raised temperature with a solution containing Chrome Fast Orange R or Cloth Fast Black B and acetic acid. In the case of the orange dyeing, the bath is subsequently cooled, potassium chromate is added and the liquid is boiled. In another example, viscose is cast into the form of a film and coagulated by means of ammonium sulphate solution. The film is passed into sodium hypochlorite solution, and then through sulphuric acid and washing baths. In another .example, viscose is extruded into a solution of sodium sulphate and acetic acid at raised temperature. The filaments are passed into an aqueous solution of ammonia and sodium hypochlorite. The filaments may be dyed with Naphthochrome Cyanide R or Neolan Green BL.