Summary
Recently enacted local regulations banning the use of resins containing bisphenol-A (BPA) will impact the metal packaging and infant care markets the most. BPA-free alternative technology is available but users and converters in these industries will have to make tradeoffs and in some cases invest in new equipment and tooling to make the switch.
Analysis
Suffolk County (New York) has enacted the first regulation banning the use of resins made from bisphenol-A (BPA) in infant care beverage containers (baby bottles, sippy cups). Pending regulations elsewhere can be expected to follow suit despite the fact that debate continues within the scientific and regulatory communities regarding the safe use of BPA.
BPA is a key ingredient in the production of epoxy and polycarbonate resins. BPA mimics certain human hormones and this has lead to the regulatory actions. Residual unreacted amounts of BPA in low concentrations in the resins have raised concerns about the effect on human health when these resins are used to package or dispense food where the potential exists for migration into the food/beverage.
Setting aside the debate of whether the low concentrations of BPA are harmful, it is worth exploring the alternatives.
Polycarbonate is known for its crystal clarity, relatively high melt point and impact resistance. It has found use in a number of applications such as non-packaging water sports bottles, baby bottles, water dispensing bottles, appliance containers (e.g. food processors) to mention a few. In each application the polycarbonate comes in intimate contact with a food or beverage. Migration of BPA is possible in each of these applications and accelerates at higher temperatures.
Several alternatives exist for these applications with certain compromises:
Acrylic - has been used in many of these applications in the past, but lacks impact strength and can yellow with time. Over time polycarbonate displaced acrylics due to better overall properties and narrowing cost difference. Certainly acrylic remains an option with applications such as appliance components.
Polyester - is best known for its widespread use in packaging of beverages such as soda. Polyesters are among the best alternatives for polycarbonate and has most of the features of polycarbonate. Eastman has announced a product line specifically to replace polycarbonate in many of the water and infant care applications. Cost and processability will be likely tradeoffs.
Polypropylene - is a another alternative that has been used in the past for water bottles and infant care containers. Polypropylene is limited to low temperature applications and is generally translucent but not clear. Polypropylene is an alternative to polycarbonate in the lower performance applications.
Perhaps more problematic, but for now less controversial and less likely to be regulated, are epoxy resins used in coatings for the interior liners for tin-plated food cans and certain aluminum beverage cans. Epoxies are known for their ability to protect metals from corrosion and are, to now, known as relatively inert. The alternatives for epoxy resin in can coatings are rather limited but include polyester, polyacrylate, alkyd resins and PVC organosols. None of theses resins are exact "drop-ins" for epoxy. Each would require a substantial tradeoff in cost and processability (and potential capital investment) for the can maker. Furthermore, certain of the alternatives may have their own health effects issues. Fortunately, epoxy can coatings are under less scrutiny than polycarbonates.
