Mill Experience With Psas, 2000 Recycling Symposium Proceedings

Loreen Ferguson, Ryan DeBerry, Robert Shaw--American Fiber Resources (AFR) has been working with the United States Postal Service (USPS), United States Department of Agriculture Forest Products Lab (FPL) and the Springborn Testing Resources (STR) as part of the Environmentally Benign Adhesive Program. The objective of this program is to identify pressure sensitive adhesive formulations that are capable of being removed through the recycling process. The current PSA formulations cause considerable problems in the recycle mill as they are difficult to remove by screening or centrifugal cleaning, as the particle shape is easily deformed and the specific gravity is essentially that of fibre or water. Three pressure sensitive adhesives were tested at AFR. One was a baseline product and the other two were candidate formulations. The PSAs were introduced at a sufficient level to cause a stickies spike in the pulper that was clearly above the background variability. When dealing with mixed office recovered papers, the variability in stickies levels at the pulper is considerable. While it may seem foolhardy for an operating mill capable of producing 600 ADMT/day to intentionally add a high loading of stickies at the pulper, the extensive background work done by FPL and STL ensured that there was a good probability that the trials would be non-events. The results of the full-scale mill trials are presented in this paper. The process successfully removed the new formulations of pressure sensitive adhesives.