Effect of Printing Methods on the Recyclability of Next-Generation Pressure Sensitive Adhesives for Postage Stamp Use, 2000 Recycling Symposium Proceedings

Rajendra Kumar--Combinations of three different next generation pressure sensitive adhesives with both offset and intaglio printing on test stamps were examined with regard to particle size distribution upon recycling. Rubber, acrylic, and tackified acrylic next generation adhesives were investigated and compared to an offset printed baseline adhesive sample. In general, it was found that all of the newer adhesives were equal to or better than the baseline material in terms of removal by screening methods. Specifically, it appears from this limited study that a combination of a rubber-based PSA with offset printing produced the greatest removal under a standard screening protocol, and that offset-printing is preferred in terms of screenability of particles. A "screenability" index was calculated and corroborated the findings of the particle size distributions. More work is needed to examine a greater variety of next generation pressure sensitive adhesives with regard to their complete behavior in recycling processes. This work will ultimately help to facilitate the transition of the US Postal Service to a more recyclable adhesive composition for stamp production.