| 摘要 |
<p>Regenerated cellulose filaments are produced by extruding viscose, to which has been added 1.0-10 per cent by weight, based on the weight of the cellulose in the viscose, of a polyethylene oxide of average molecular weight 300-10,000, preferably 1000-3000, at a sodium chloride salt point of 5-18 into an aqueous coagulating bath containing a proportion of sulphuric acid 0.8-1.5 times that of the caustic soda in the viscose and 3-20 per cent of zinc sulphate. The optimum concentration of polyethylene oxide for producing yarns of normal denier by the "hot stretch" process, as described in Specification 467,500, [Group IV], is 1 to 4 per cent, based on the weight of the cellulose. When spinning yarns and rayon staple of higher denier, higher concentrations of polyethylene oxide are desirable. The preferred salt point for good yarn properties is 6-16 and for good cord properties 8-13, the best all-round properties being obtained when the salt point is 9.5-11 and the viscose contains 7-7.5 per cent of cellulose. In an example, viscose containing 7.0 per cent of caustic soda, 7.5 per cent of cellulose, 41 per cent based on cellulose of carbon disulphide and 1.5 per cent based on cellulose, of a polyethylene oxide having an average molecular weight of 1000 is extruded at a salt figure of 10.2 and at 55 DEG C. into an aqueous coagulating bath containing 8.0 per cent of sulphuric acid, 14 per cent of sodium sulphate and 6 per cent of zinc sulphate. The yarn thus formed is stretched 87 per cent in an aqueous bath at 95 DEG C. containing 3 per cent of sulphuric acid, 0.8 per cent of sodium sulphate and 0.4 per cent of zinc sulphate, and is subsequently treated in a hot aqueous acid bath of the same constitution. Cords made from yarns produced by the process of the invention have greater fatigue life. Textile yarns similarly produced have an increased resistance to abrasion and soiling. Specifications 557,218, [Group IV], 634,868 and 786,319 also are referred to.</p> |
