Waterborne epoxy dispersions have been employed effectively for many years in the coatings market primarily for the surface protection of concrete and metals. These products were developed in response to environmental regulations to reduce solvent levels in coatings. Since these dispersions adhere well to a wide variety of substrates and provide a high degree of strength and resistance to service environments, they have also naturally found applications as adhesives.
Epoxy dispersions can also easily be blended with other waterborne polymers to make modified latex adhesives. The resulting hybrid adhesive produces performance properties and application characteristics that are superior to the originating latex system.
This article will review the chemistry behind waterborne epoxy adhesives and the formulating possibilities. The characteristics of epoxy dispersions and the performance properties of cured adhesive films will be addressed. The advantages and disadvantages of these adhesive systems will be discussed with the focus on determining whether waterborne epoxy systems can replace traditional solventborne or 100% solids epoxy adhesives.