ABSORPTION OF STARCH DURING SURFACE SIZING WITH DIFFERENT METHODS

Factors that influence starch absorption and the contribution of absorption to total starch pickup in the surface sizing process were examined on the pilot-plant scale. The rate of starch absorption was enhanced by external pressure and low starch viscosity. At constant viscosity, the starch temperature, chain length, solids content, and the degree of cationization had no effect on absorption rate. The amounts of starch pickup measured using different pilot coaters (short dwell time applicator < flooded-nip blade coater < size press applicator) indicate that total starch pickup in the sizing process is the sum of the amount of starch absorbed and the amount of starch layered on the paper surface.