| 摘要 |
<PICT:0345179/IV/1> Foils and films are obtained from solutions of cellulose compounds, gelatine and like substances with the aid of a travelling pouring base partly immersed in a coagulating bath, the process being carried out in such manner that the solution is allowed to coagulate only to a certain depth, and the coagulated layer is stripped off, leaving a residual uncoagulated layer on the pouring base. The thickness of the foil produced is controlled by the speed of travel of the pouring base, the temperature of the solution, the temperature and concentration of the coagulating bath, the thickness of solution applied to the base, and the point at which stripping takes place. As shown in the Figure, solution such as viscose flows from the slit of a pouring device 1 to form a layer of thickness a on a drum 2 which rotates in the direction of the arrow 3 and dips into a coagulating bath 4. When the layer of solution has coagulated to a depth b, the coagulated layer is stripped by the roll 5 and is led as a freely suspended foil 6 over the guiderolls 7, 8 out of the coagulating bath to further treatment baths. There remains on the drum 2 an uncoagulated residual layer of thickness c. Upon this layer fresh viscose solution is applied by the pouring device 1. Instead of a drum an endless band may be employed as pouring base. |
