Date of Award
Bachelor of Science
Pulp and Paper Technology
Proper distribution of adhesive in pigmented coatings is necessary to obtain good printability. This ___ undertaker to study the effect of varying drying rates on adhesive distribution. Using a standard substrate, coating was dried under four separate drying rates on a pilot coater equipped with an air knife coater and three sections of hot air driers. After grinding to carious derths, a spectrophotometric method was used to analyze migration behavior. The fastest rate, utilizing an infrared heater temporarily placed directly after the air knife, showed extremely uniform adhesive distribution. This was due in part to the reflective foil placed opposite the infrared heater, allowing evaporation in both directions. Successively slower rates were obtained by moving hot air zones away from the application area. The hot air driers were temperature controlled to 350°F in the hot zone and 200°F in the other two sections. Results showed surface migration directly proportional to the distance to the hot zone, contrary to the theories based on previous studies. The reason postulated for this phenomenon was "thermal migration" during the intermediate zones. Spectrophotometric analysis was found to be an effective and feasible method to study adhesive migration.
Larson, Alan, "Drying Rates, Infrared Drying, and Binder Migration" (1975). Paper Engineering Senior Theses. 341.