Epoxy resin based coatings in ship building: life cycle evaluation of potential BPA-emission

 
Marine coatings are instrumental in protecting ships from the harsh conditions of the marine environment, i.e., immersion in salt water, frequent temperature cycles, high UV exposure and bio-fouling caused by marine organisms. Consequently, protective coatings are designed to prevent chemical and atmospheric corrosion, protect against weathering, and minimize the bio-fouling of underwater surfaces. Depending on the nature of the exposure, different coating types are employed to manage degradation. Amongst the various types of materials such as urethanes, vinyls, acrylics, silicones etc. it has been estimated that epoxy resin based coatings represent the largest share - accounting for 45% of overall marine coating material consumption. Epoxy resins offer a balance between excellent corrosion resistance and cost-effectiveness, and generally have long maximum overcoat time and good recoat ability. While different classes of epoxy resins exist, the majority of them are based on reaction products derived from Bisphenol A and Epichlorohydrin. Bisphenol-A as a chemical substance has been, and continues to be, a topic of intense debate in expert circles with regard to its alleged adverse effects on human health and the environment. These arguments find their way into the wider public and have provoked concerns relating to the use of proven protective technologies. Estimating environmental exposures should provide some perspective on the use of these technologies, thus the Epoxy Resin Committee in cooperation with BiPro has conducted a series of studies to estimate the life cycle emission potential of major industry applications using epoxy resins. In this paper the life cycle of marine coatings using BPA-based epoxy resin is reviewed. During each stage of the life cycle, i.e., for the manufacturing of the resins, their service life, and ultimately their end of life, the hypothetical potential release of BPA into the environment is calculated.