In the United States, over 300 billion beer, beverage and food cans are coated with half a million metric tons of Bisphenol-A (BPA)-containing epoxy resins each year, and the global market is more than twice that large. Although there are currently no U.S. Food and Drug Administration (FDA) or other U.S. regulatory restrictions on the use of BPA-based resins in most food containers, BPA-related health hazards have been recognized by regulators, policymakers and consumers. BPA is banned from use in applications such as infant feeding plastic bottles, and California recently listed BPA as a hazardous chemical. ...

Oleoresins (derived from oxidative drying of natural oils) were used as can coatings before the emergence of BPA resin. The latter's dominance is due to its faster cure speed, excellent corrosion performance and lower cost. The recognized health hazards with BPA resin have led many can coaters to revisit oleoresins; however, slower kinetics of the oxidative drying do not work with current high-speed can coating operations. Metallic driers cannot be used to accelerate the cure speed, as they are not permitted for food-contact use. The resins derived from epoxy, hydroxyl or carboxyl derivatives of natural oil have been studied as alternatives to BPA resin, but they do not have adequate corrosion and acid resistance, mainly because of the presence of an open micelle structure in the cured coating.

Recent developments introduced as BPA substitutes are still epoxy-based resins; they are derived from a BPA-like structure and use the oxirane ring for the resin cure.