GB368230A - Improvements in the production of fine threads of artificial silk - Google Patents

Abstract

<PICT:0368230/IV/1> <PICT:0368230/IV/2> Artificial threads are spun by the dry spinning method in the usual manner but before they have become completely solidified they are allowed to issue from the spinning chamber and are subjected in this plastic condition to the action of a swelling agent which does not dissolve the substance of the thread, and then stretched. As swelling agents there may be used water, benzene hydrocarbons, alcohols, chlorinated hydrocarbons, or other single or mixed liquid which does not dissolve cellulose esters or ethers. Softening agents which remain in the fibre are excluded. Sizing agents may be added to the swelling agent. The latter may be used in gaseous or liquid form. The threads may thus be stretched by 30 per cent or more, and at the same time the strength is increased. In an example threads of acetyl cellulose from a nozzle a, Fig. 1, in the cell b, issue from the cell while still plastic and pass into a stretching chamber c into which steam is introduced. In another example the threads after leaving the spinning chamber pass through a bath containing benzene and an oily size and are then stretched on the way to a winding spool. In a further example, the thread on issuing from the spinning chamber b, Fig. 3, is sprinkled with alcohol issuing from a jet m and is then passed through the bath i also containing alcohol. The thread passes over guide k and the curved lip n of the bath i and is wound on the spool h, the stretching occurring between this spool and the guide.