CAN LABORATORY AND PILOT RECYCLING TRIALS PREDICT ADHESIVE REMOVAL IN COMMERCIAL RECYCLING SYSTEMS? RESULTS FROM THE USPS ENVIRONMENTALLY BENIGN STAMP PROJECT

摘要

The ultimate goal of the US Postal Service (USPS) Environmentally Benign Stamp Program is to develop stamp laminates, i.e., face paper, adhesive and siliconized liner, that do not cause difficulties in recycling mills. The criterion for success, and the USPS definition of benignity, is the avoidance of process and product quality hardships when such PSA laminates are introduced in significant quantities. However, since it is neither prudent nor costeffective to test experimental adhesive materials at mill scale, we have developed laboratory scale (360 g pulp) and pilot-scale (112 kg pulp) test methods for determining adhesive performance in recycling environments. Comparison of results from these small-scale trials with mill trial results has shown that there are strong correlations. Furthermore, specifications for environmentally benign stamp adhesives, based on laboratory and pilot results, have been set and accepted by the recycling industry.