Antioxidant Mechanisms and Synergies for Hot Melt Adhesives, 1993 Hot Melt Symposium Proceedings

Paul E. Stott

William S. Post

The hot melt adhesive formulator is exposed to a large body of information on how various polymers, resins and waxes will affect the performance of a hot melt adhesive. Another small but key ingredient in the hot melt formulation is the antioxidant. The antioxidant’s function is to provide stability for the hot melt system. The rationale of this paper is to summarize current theory on antioxidants. The focus is on the mechanisms of antioxidant stabilization and the objective is to introduce the hot melt formulator to the wide range of antioxidant strategies available. While the focus of the paper involves a systematic summary of current antioxidant mechanisms, the general methodology of measuring hot melt performance involves standard industry tests for viscosity, shear adhesion, and peel strength. This extensive laboratory review of five hot melt systems leads to the conclusion that while there was little performance difference demonstrated between a range of antioxidants on an equivalent weight basis, dephenylamine/hindered phenol blends are cost effective. Thin film aging also proved a better predictor of antioxidant performance in SIS systems than traditional methods.