Coating Binder Migration and Affected Parameters: Influence of Coating Process

The coating binder in cross-section of coating layer will be migrated, the binder concentration will be different in z-direction of coating layer, which affect some properties of coated paper. The paper studied the effects of coating progress on binder migration and affected factors. The z-direction distribution of the coating binder which was tagged with Br in coating layer and its concentration in coating surface were examined quantitatively by using SEM-EDXA and ESCA analysis. During coating process the drying rate, dwell time from coating device to dryer and coating weight affect the binder migration. The mechanism of binder migration was proposed. The results indicated that the degree of binder migration is directly proportional to the drying temperature and coating weight, but reduces with extending the dwell time.