| 摘要 |
<p>In a process for desulphurizing viscose artificial silk, the freshly spun artificial filament from an acid spinning bath is washed immediately after its precipitation with diluted, and as far as possible salt-free, sulphuric acid in individual filaments over a filament stretch of <PICT:0432692/IV/1> several metres, then washed preferably with hot water and dried in known manner. Suitable concentration of sulphuric acid as 80--170 gms., advantageously about 120 gms. per litre. Any sulphur left in the filament may then be easily removed e.g. by a simple cleansing with soap, such as is frequently involved in the dyeing or preparation of the products. In a constructional form, the viscose filament 3 issues from nozzle 1 into the spinning bath 2 and is fed by the driven take-off roller 4 to a pair of inclined cylinders 5, 6 along which it moves helically. Dilute sulphuric acid is sprayed at 8 from the supply pipe 9 on to the upper roller 5 in such a limited amount that it spreads over the roller and only runs off into vessel 10 at the lower edge of the cylinder. Preferably hot water is similarly sprayed from the supply pipe 12 through the spray device 13 on to cylinder 6. The sulphuric acid may be left to allow the removed sulphur to coagulate, filtered, and used again so long as it has not too great a content of salts. Specification 394,216 is referred to.</p> |
