Can Coatings: Technology Or Process?

The article about bisphenol A and its use in can coatings and adding it to California Proposition 65 has me wondering (C&EN, Feb. 11, page 24). Are there data showing the extractable levels of bisphenol A from the epoxy coating that measure above acceptable levels to cause a concern when extracted by the can contents and digested? No one wants to be exposed to harmful chemicals that are going to cause a problem in the human body over time.

Because bisphenol A is reacted with epichlorohydrin to produce the epoxy coating used in inner can coatings, is the reaction not going to completion under the proper curing conditions? Are the two components used to produce the epoxy resin not being measured out to the optimum levels to fully complete the cure mechanism and not leave residual bisphenol A available for extraction and digestion?

The chemical industry is constantly bombarded regarding “bad chemicals,” but is the real issue here the technology or how it is being processed in the field that is truly the one of concern?

Cosmo V. Sabatino
Pepperell, Mass.