Novel Approach in the Design of an Environmentally Benign Emulsion Adhesive, 2000 Recycling Symposium Proceedings

Jong S. Guo, M. Ojunga-Andrew, Sharon D. Trembley, Dennis E. Webster, and Augustin T. Chen --There has been a growing concern that the pressure sensitive adhesives currently used in many products are not environmentally friendly and cause the “stickies” problem in the paper recycling process. Most of the earlier repulpable adhesives were water-soluble Pressure Sensitive Adhesives (PSAs) and usually presented a problem with poor moisture resistance and/or lack of adhesion, as well as accumulation in the water stream. Extensive industrial research has been devoted to the development of a repulpable PSA. Solutia has developed a novel technology in the acrylic emulsion polymerization process that produced a new screenable/floatable adhesive with unique performance properties, such as, excellent adhesion, high shear, and great moisture resistance. A hypothetical particle morphology was proposed to explain the high performance of the new adhesive. Atomic Force Microscopy (AFM) was used to understand the film formation of the adhesive particles. Scanning Electron Microscopy (SEM) was also used to study the adhesion of the PSA to substrates. Under the United States Postal Service (USPS) testing protocol for stamp application, the new adhesive exhibits not only excellent permanence/aging performance, but also, outstanding performance in repulpability with a final dirt count of less than 5 ppm.