GB320161A - Process of making regenerated cellulose structures - Google Patents

Abstract

320,161. Dunlop, S., (Morse, E. H.). July 24, 1928. Cellulose xanthates, processes for making films and filaments from.-The manufacture from viscose of films, bands, threads &c., but particularly of films, is effected by passing the film &c. through an acidified coagulating solution and then subjecting it to dilute acid under such conditions that the acidity increases as the treatment proceeds, the use of conveying bands or the like being avoided. Thus, a film from viscose may be passed into a coagulating bath comprising a slightly acid solution of ammonium sulphate and thence through three regenerating baths containing successively increasing concentrations of sulphuric acid and decreasing concentrations of salt; the baths are regenerated constantly or intermittently. Suitable baths and conditions of treatment are described. Alternatively, the film may be passed through a single bath in counterflow to a regenerating and coagulating solution, the bath being supplied with acid at the end at which the film leaves and the composition of the bath being suitably adjusted at intermediate points, for instance by addition of salts. After regeneration, the film may be passed through washing, desulphurizing, bleaching, dyeing, and softening baths, as required.