Manufacture of polyvinyl alcohol threads

542,942. Artificial filaments. COURTAULDS, Ltd., and WILSON, D. L. Aug. 2, 1940, No. 12527. [Class 2 (ii)] Artificial filaments of polyvinyl alcohol are obtained by extruding an aqueous solution of water-soluble polyvinyl alcohol into a bath consisting of an organic liquid having an appreciable solvent power for water. The organic liquid may be a mixture of such liquids and it may contain water or other additions. Spinning solutions of various concentrations, viscosities, and temperatures may be used. The organic setting liquid may be acetone, ethyl lactate, or ethylenel glycol mono-ethyl ether. In order to prevent deterioration or sticking of the filaments during the subsequent drying operation owing to the presence of an increasing proportion of water, the filaments may be passed from the setting bath into another bath containing a liquid of different composition from the first. The second bath may consist of a solution of diethylene glycol mono-ethyl ether (hydroxyethoxy-ethyl ether), or ethylene chlorhydrin, and water. The filaments may be stretched, e.g. while passing through the second bath. The filaments obtained are weakened by cold water and dissolved by hot water. They may be rendered resistant to water by treating them with formaldehyde or with an acid chloride. Specification 542,943 is referred to.