| 摘要 |
Viscose is spun into a hot aqueous acid saline bath, and the threads so produced are stretched to the maximum extent possible without rupture in a second hot aqueous acid bath containing a lower concentration of acid than the first bath, the threads being allowed to shrink freely after passing through the second bath while still in the acid state, whereafter the threads are washed (while completely free from tension) in such a manner that they can absorb moisture to a maximum extent, and are then treated in an oil-in-water emulsion bath from which they are supplied to a collecting device; they are then passed, while subjected to predetermined tension, over a system of drying rollers heated to over 100 DEG C. on which they are initially dried to a moisture content of not below 60 per cent (based on the dry thread), before being finally dried by passing them through a drying shaft in counter-current to a stream of hot air, at a tension less than that at which they left the drying rollers. In the example, a viscose is spun into an aqueous bath having a temperature of 50 DEG C. and containing 126 grams per litre of sulphuric acid and sodium, magnesium and zinc sulphates. The threads are thereafter stretched by 100 per cent in a second aqueous bath containing 4 per cent of sulphuric acid at a temperature of 95 DEG C. The threads are allowed to fall freely from the second bath delivery roller into a centrifugal spinning pot, in which they are covered by a cloth and sprayed with after-treatment liquids. The threads are then fed from the pot in the form of a tow through a mangling device, passed through an oil-inwater emulsion finishing bath and then passed through a second mangling device to reduce their moisture content to about 145 per cent based on the dry weight of the thread. The threads are then led at predetermined tension over drying rollers maintained at 140 DEG C. and their moisture content is thereby reduced to 60 per cent (based on dry thread). Finally the threads are led from the rollers through a drying shaft in countercurrent to a stream of air at 100-120 DEG C.
|
