PILOT-PLANT DYNAMICS AND AKD SIZING

The currently held views on the mechanism of AKD sizing appear to be sufficient for predicting the behaviour of the size under controlled paper machine conditions. Extending a recently developed method for analysis of unreacted AKD it is possible to estimate the quantity of this material in thin stock and white water Dynamic studies of sizing development were undertaken using a pilot plant paper machine. The AKD conventionally emulsified in cationic starch exhibited good first pass retention. The rate of reaction in white water can be predicted using a knowledge of the residence time distribution. Experiments were done under neutral, acid and alkaline conditions. Sizing development was measured, using the Hercules Size Tester after times varying from six hours to 30 days. Satisfactory sizing could be obtained under all conditions. A preliminary study of the effect of dryers was also made.