| 摘要 |
<PICT:0596772/IV/1> <PICT:0596772/IV/2> A process for producing hollow filaments comprises the extrusion of a viscose having a salt point of 5-6 and containing 1.9-2.5 per cent by weight of total sulphur, 6-9 per cent sodium hydroxide, 6-9 per cent cellulose and from 5 to 35 per cent of sodium carbonate (calculated on the cellulose content) into a coagulating bath containing 11-12.5 per cent of sulphuric acid, 21-25 per cent sodium sulphate and 5-6 per cent zinc sulphate. The temperature of the bath may be maintained at from 40 DEG to 60 DEG C. Filaments prepared by this process have a cellular structure comprising a plurality of voids separated by partitions which radiate irregularly from at least one internal point of the filament as shown in Fig. 1. The voids overlap and lie irregularly spaced along the axis of the filament as shown in Fig. 2. This structure enhances the rigidity of the filaments, but does not effect their flexibility. Dyes or pigments may be present in the spinning solution. Stretching up to from 40 to 50 per cent of their length may be applied to the filaments. The immersion time in the coagulating bath depends on the denier. Filaments so obtained may be cut into staple fibre, may be crimped by shrinkage or may be impregnated with synthetic resins. They are particularly useful for the manufacture of apparel where lightness and protection from heat and cold are of importance. In an example, a viscose of salt point 5.5 having 8.4 per cent sodium hydroxide content, 7.3 per cent cellulose, 2.3 per cent total sulphur and 25 per cent sodium carbonate (based on cellulose) is extruded to produce a 120-filament thread of denier 300, into a bath at 50 DEG C. containing 12.3 per cent sulphuric acid, 22 per cent sodium sulphate and 5.3 per cent zinc sulphate. The immersion is 20 inches. A 40 per cent stretch is effected after leaving the bath. |
