摘要:
A process for determining the polymer concentration in a spinning dope solution involves measuring the propagation velocity of ultrasonic sound in the solution. The process prevents fluctuations in the polymer concentration as much as possible, and is therefore highly suitable for application in the production of fibers with consistent properties. An ultrasonic device used in the process is easier to clean, install, and calibrate than other presently commercially available devices.
摘要:
The invention pertains to a process for determining the acidity of a washing solution for removing adhering acid or base from a fibre. The determination is carried out by using a combination of at least two different analytical methods, at least one of which is selected from the density, conductivity, ultrasonic sound, and refractive index measurements. The determination makes it possible to adjust the acidity of the washing solution in such a way that fibres with a minimum amount of adhering acid or base can be produced.