(Received 6 January 1997; accepted 18 April 1997)
Hoechst Celanese has improved the precision of viscosity measurements from ±6 to ±2 centipoise by switching from manual to automated testing. Solution viscosity is one of the most critical quality parameters in the production of cellulose acetate flake. In the past, the company used a modified Cannon-Fenske tube for viscosity measurements. Operator influences, including time measurements, start and end points, bath temperature, and other factors, made it impossible to achieve optimal accuracy. Switching to automated differential viscometers eliminated operator influences from the measurement process thus enabling far more precise process control.
Paper ID: JTE11365J