Development of Environmentally Benign Pressure Sensitive Adhesives
The U.S. Postal Service (USPS) took the initiative to spearhead a program designed to develop an environmentally friendly PSA for use in the U.S. postage stamp. Extensive industrial research has been devoted to the development of a repulpable PSA. Solutia, a major PSA manufacturer, collaborated with paper producers, release-liner companies, converters, paper-recycling mills and testing labs for the development of a benign PSA.
This article describes different designs of PSAs and the pulping behavior of PSAs having different polymer structures. A novel acrylic emulsion PSA was developed with excellent adhesion properties, moisture resistance and recycling performance. The adhesive, designed with enhanced hydrophobicity and cohesive strength, can be easily removed during the early stage of the recycling process. This new emulsion PSA (GME 2956) has shown outstanding recyclability in the pilot-plant and mill-scale processes and is currently qualified for benign postage-stamp usage in the United States.