Pilot Plant Study of the Recyclability of Pressure Sensitive Adhesives (PSA), 2000 Recycling Symposium Proceedings

Bruce R. Crossley, David B. Grimes, Said Abubakr, Rajendra Kumar--This paper discusses the operation and results obtained from a pilot plant study of the recyclability of post consumer pressure sensitive adhesive (PSA) postage stamp material. The trial work was carried out in May of 1999 at the Beloit Pulping Pilot Plant in Pittsfield MA., in cooperation with the U.S. Postal Service, and the U.S.D.A. Forest Products Lab in Madison WI. This work is a part of a much larger USPS development program currently under way with the main objective being to develop postage stamps that do not adversely affect the environment. The goal of the project is to develop a PSA material which can be successfully recycled in the typical mixed office waste (MOW) deinking system producing a pulp for inclusion in printing and writing grades. This trial looks at a new generation” PSA developed specifically to improve its recyclability when compared to the products in current use by the Postal Service. The adhesive supplied for these trials breaks down in the pulping process into primarily larger sized and two dimensional particles which are generally removable using very fine slotted screens. The screening system design and mass rejects rates at which the screens are run both have an impact on the removal efficiency of the adhesive used for this testing.