Breakage and Extrusion of Pressure Sensitive Adhesives in Industrial and Laboratory Screening Processes, 2001 Pulping Conference Proceedings

B. E. Lucas, R. A. Venditti, H. Jameel--The objective of this research was to elucidate the behavior of pressure sensitive adhesives in industrial equipment and to further understand why inefficiencies exist in the removal of pressure sensitive adhesive particles. This was accomplished by contrasting the screening results of an industrial pressure screen with two laboratory screens. The considered devices were a hydropulper, an industrial pressure screen, two laboratory screens, and a high shear mixer. Using the same pulp, the laboratory screens were much more efficient than the industrial screen in removing the adhesive particles. This was due to the breakdown and extrusion of pressure sensitive adhesive particles in the industrial pressure screen. Also, pressure sensitive adhesive particles broke down to different average particle sizes depending on the equipment and the adhesive material. A laboratory pulper and high shear mixer were found to breakdown PSA particles to a size reflective of breakage in an industrial pressure screen. These findings are useful in analyzing the removal of adhesive particles by recycling operations.