Date of Award
Bachelor of Science
Paper Science and Engineering
Dr. Ellsworth Shriver
As the trend in printing recycled paperboard shifts toward the rotogravure process, the surface smoothness of the paperboard is becoming increasingly important. Also, as recycled paperboard machine speeds increase, greater demands are being placed on the coating process and formulation to yield superior coating characteristics. The objective of this research project is to determine a base coat formulation that improves the base coating characteristics in high-speed recycled paperboard. This study examines the replacement of a traditional #1 clay with calcined clay and fine particle clay, which through their different properties alter the characteristics of the coating. The bulky calcined particles are more effective at filling the micro-valleys on the surface of the paperboard, while the smaller fine particle clay particles help prevent the coating from becoming dilatent. The less costly fine particle clay also offsets the high cost of the calcined clay.
The lab experiments on the Cylindrical Laboratory Coater have shown that at a constant coat weight, 20 parts calcined clay, 32 parts fine particle clay and 48 parts #1 clay provided improved smoothness and brightness while maintaining adequate flow characteristics. Above 20 parts of calcined clay the coating consisting of 10 parts calcined clay, 32 parts fine clay and 58 parts #1 clay provided almost the same smoothness and brightness results, but costs less. This would be the most cost effective coating formulation for improving the surface smoothness and brightness characteristics of recycled paperboard.
Because only a relatively small amount of research has been done in this area, this project could be extended into any number of areas including the addition of delaminated clay, effect of coat weight, and pilot/machine trials.
Mikus, Lance S., "Smoothness Improvement of High Speed Recycled Paperboard through Base Coating Formula Optimization" (1994). Paper Engineering Senior Theses. 308.