Water borne adhesives, derived from emulsion polymerization processes, are particularly susceptible to performance loss on exposure to high humidity conditions. The achievement of performance properties similar to solvent-based adhesive has for a long time been the "holy grail" of water borne adhesive formulators.
During the 1970s when the first major push was on to replace solvents in adhesive systems, formulators believed that water borne formulations should eventually become available having properties equivalent to conventional solvent based systems. Unfortunately, this is not the case although significant advancements in performance properties have been made. As a result, hot melt and UV curable adhesives have taken much of the spotlight away from the water borne systems.
Even so, the interest in solventless adhesive systems continues to increase for several reasons including environmental and economic factors, and the market for water based emulsion adhesive has actually increased in recent years.