| 摘要 |
<p>Filaments, films and like products of regenerated cellulose consisting entirely of skin are produced by extruding viscose containing about 0.1 to 4 per cent, preferably 0.3 to 2 per cent, based on the weight of the cellulose in the viscose, of an alkylene oxide adduct of tall oil, of its extracted acidic components or of its extracted hydrogenated resin acid components, into an aqueous bath containing about 10-25 per cent, preferably 15-22 per cent, of sodium sulphate, 3-15 per cent, preferably 4-9 per cent, of zinc sulphate or the water-soluble sulphate of another heavy metal, and sulphuric acid, the sulphuric acid content of the bath exceeding the slubbing point but being below the concentration at which neutralization of the caustic soda of the viscose is so rapid as to produce products consisting of skin and core. Each molecule of adduct may contain about 6-75 or more ethylene oxide units, preferably 10-30 ethylene oxide moles. per mole. of tall oil. The adduct may be added at any stage in the production of the viscose, e.g. it may be added to the cellulose material used for the preparation of the viscose. It is preferably added, however, after the solution of the cellulose xanthate in dilute aqueous caustic soda solution. The temperature of the spinning bath may be 25-80 DEG C., preferably 45-70 DEG C. The sodium chloride salt test of the viscose should be above about 8 and preferably above 9 when the viscose is spun. In an example, viscose containing 7 per cent of cellulose, 6 per cent of caustic soda, 41 per cent (based on cellulose) of carbon disulphide and 0.3 per cent of an ethylene oxide-tall oil adduct containing 16 ethylene oxide units per molecule is spun at 10.3 salt test into a spin bath at 60 DEG C. containing 7.5, 8.0 and 18 per cent of sulphuric acid, zinc sulphate and sodium sulphate respectively. The filaments thus formed are then stretched 82 per cent in water at 95 DEG C., washed and dried. Small proportions of the adducts may also be added to the spin baths.</p> |
