GB357527A - Improvements in the manufacture of artificial threads or other products from cellulose compounds - Google Patents

Abstract

Artificial threads, films, and other products are obtained from xanthates of alkyl or aralkyl cellulose derivatives, or of cellulose ethers of oxyalkyl monocarboxylic acids by bringing the product into the appropriate shape and acting thereon with a coagulating agent, or an agent which has both a coagulating and plasticizing effect, or first with an agent having a coagulating effect and then with an agent having a plasticizing effect. The xanthates may be mixed with cellulose xanthate. This may be effected by mixing solutions of the ingredients or dissolving one in a solution of the other, or by xanthating a mixture of the cellulose compound with unchanged alkali cellulose. Alkali soluble cellulose hydrate, cellulose compounds, proteins, gelatine, and softening agents such as glycerine, glycol, soap, glucose, Turkey red oil, drying oil, non-drying oil, and agents such as halogen derivatives of polyhydric alcohols may be added to the solutions of the xanthates. In an example, wood pulp or cotton linters are steeped in caustic soda solution and the mass is pressed, comminuted, and shredded. Di-methyl sulphate is added slowly with continuous kneading of the mass. When the first reaction has ceased a further quantity of caustic soda solution and then of dimethyl sulphate is added. The product is washed with water, and pressed. It is then treated with caustic soda, shredded, and treated with carbon bisulphide. The xanthated product is dissolved in caustic soda solution, filtered through cloth and cottonwool, aged, and spun into a coagulating or plasticizing bath. In other examples diethyl sulphate, or benzyl chloride is used instead of dimethyl sulphate. In the case of benzyl chloride, reaction with alkali cellulose is assisted by heating the mass. The crude benzyl cellulose is extracted several times with alcohol and then washed with water. It is then xanthated and converted into artificial threads. Purification of the benzyl cellulose may, however, be dispensed with. In other examples a cellulose ether of glycollic acid is dissolved in caustic soda solution and treated with carbon bisulphide. Homologues of ethyl or benzyl cellulose such as propyl- or amyl-cellulose may be employed. Cellulose ethers, lactic acid or oxybutyric acid may also be employed. When strong acid plasticizing baths are used, the threads on leaving the bath may be subjected to low temperatures before being washed, for example they may be collected on hollow spools containing solid carbon dioxide, or a freezing mixture. The threads may be desulphurized in the ordinary manner, or by treatment with hot and strong sodium sulphide solutions. In another example, cotton material is impregnated, filled or coated with a solution of the xanthated cellulose compound containing filling material such as talc, china clay or zinc white, or a pigment such as mica or lampblack. The material with or without drying, and if desired in a state of tension is passed through a coagulating or plasticizing bath, and then washed and dried. The process is applicable to the manufacture of artificial silk and other threads, films, coatings, layers; dressings for textiles, paper, and leather; adhesives and cements; plates and plastic compositions; thickening or fixing agents for pigments in textile printing. Specifications 177,810, 203,346, 203,347, 335,993, [all in Class 2 (ii), Cellulose &c.], 341,899, and 357,167 are referred to.