Patent GB-335993-A (GB)
Title: Manufacture of artificial threads or other products from cellulose compounds
IPC: C08B13/02
Filed: 1929-03-25
Abstract: 335,993. Lilienfeld, L. March 25, 1929. Divided on 335,906. Yarns &c., treating with liquids.-Artificial threads, films, and other products are made by bringing into appropriate form or shape a cellulose compound which contains at least one CSS group and at least one radical of a di- or polyvalent alcohol-which compound is produced by converting the whole or part of the cellulose employed into an oxyalkyl ether of cellulose and treating the product thus obtained with carbon bisulphide in the presence of alkali-and then acting upon this form &c. with a coagulating agent which has also a plasticizing effect on the material during or immediately after its coagulation, or first with a coagulating-agent and thereafter with an agent which has a plasticizing effect on the freshly coagulated material. The oxyalkylcellulose xanthates may be worked up into threads &c. alone or with other colloids, e.g. cellulose xanthate. Thus, the oxyalkylcellulose xanthate may be dissolved in viscose or its solution mixed therewith, or cellulose xanthate may be dissolved in a solution of oxyalkylcellulose xanthate; carbon bisulphide may be allowed to act on a mixture of oxyalkylcellulose and cellulose; or alkali soluble derivatives of cellulose, proteins, gelatine, &c. may be admixed with oxyalkylcellulose xanthates or their solutions. Softening agents, e.g. glycerine, glycol, glucose, soap, turkey-red oil, &c. may be added to the solutions. As plasticizing agents, liquids with a high content of strong mineral acid, e.g. not less than 35 per cent of H2SO4 or equivalent acid, or baths containing a. fair amount of zinc halide with or without acid are employed. The products are stated to possess a satisfactory and in some cases excellent wet and dry tenacity, and a pliability, extensibility and elasticity sufficient for all practical purposes. The extensibility of threads &c. may be further increased by treatment with shrinking-agents, as described in Specifications 281,352, 312,197, 323,731 and 323,732. The oxyalkyl derivatives of cellulose may be produced as described in Specifications 231,807 and 335,994, [both in Class 2 (ii), Cellulose &c.]. In examples, (1) Artificial threads are produced by spinning solutions containing particular oxyalkylcellulose xanthates descrihed in Specification 335,994, [Class 2 (ii). Cellulose &c.], into a bath of sulphuric acid which is in some cases preceded by a coagulating-bath comprising (a) a solution of ammonium sulphate, (b) an acid solution of sodium bisulphate or (c) an acid solution containing sodium ammonium and zinc-sulphates and glucoses; a range of solutions and spinning conditions is given. The action of the acid may be interrupted by subjecting the threads leaving the hath to a low temperature, e.g. -5 to -15‹ C. before washing, for instance by collecting it on a hollow spool containing solid carbonic acid, a freezing mixture, &c. After washing, the threads may be heated or steamed, e.g. at 100-110‹ C., before or after drying. The threads are desulphurized bv treatment with hot or warm alkali sulphide solution containing at least 5 per cent of alkali sulphide calculated as Na2S, 9H2O. (2) Films are produced in a similar manner using a suitable hopper or slit. (31 Cotton is impregnated or coated one or several times with a solution produced as described to which is added' a filler such as talc or china clay, or a dvestuff or pigment, e.g. mica. or lampblack, and the fabric is passed through the coagulating and plasticizing bath and afterwards washed and dried. (4) Sheets of cardboard or thick cloth are pasted together with a. thick solution of the oxyalkylcellulose xanthate. and after pressing or calendering if desired, the material is introduced into sulphuric acid of 50-60% at -5‹ C. until permeated, when it is washed free from acid nnd dried. (5) A pasty solution as in (4) is freed from gas bubbles and formed into a thick plate which is introduced into 60 per cent sulphuric acid at -5‹ C. and after coagulation the plate is washed, dried and, if desired, desulphurized or bleached. The products referred to are artificial threads and films, staple fibre, &c.