The Urethane Blog

Valspar non BPA Can Coatings Strategy

Valspar: How we engaged stakeholders to solve the BPA dilemma

Businessman holding a tin phone can to his ear
ShutterstockMinerva Studios
We found a silver lining in the process of replacing Bisphenol-A.

Bisphenol A (BPA)-based epoxy coatings are the most commonly used protective lining for metal food and beverage packaging. BPA-free campaigns from organizations such as the Breast Cancer Protection Partners, Clean Production Action and the Natural Resources Defense Council have raised awareness of and consumer demand for BPA-free products.

Consumer-facing food processors, can manufacturers and others who have relied on epoxy-lined cans for decades need to respond, but face the challenge of finding safe substitutes for BPA-based coatings that provide all the same functional benefits at reasonable cost.

Responding to this market opportunity, our company, Valspar, a major provider of linings to can manufacturers, undertook a novel approach to finding a safe, functional alternative that provides a promising model for how other companies might approach such challenges and opportunities.

BPA has been the subject of intense scrutiny with respect to its hormonal, estrogenic impacts, including reproductive and developmental effects. Unfortunately, common alternatives such as Bisphenol S and Bisphenol F also have been reported to show some of these effects.When formulating a food or beverage can coating, non-epoxy-based alternatives would seem to be a logical approach. Acrylic, vinyl, oleo, polyethylene solutions were considered, but none have the versatility to meet the diverse and critical performance demands of a can manufacturing plant that cranks out 6 million cans per day.

Valspar needed to find a solution that provides the performance properties of BPA-epoxy coatings without the perceived drawbacks in human and environmental health. Using an approach much like the pharmaceutical industry uses to find new drug molecules, Valspar developed a BPA-free solution with a basic building-block molecule that is not estrogenic, does not induce genetic damage (genotoxicity), meets all food safety requirements, has excellent performance and will not migrate into food.

To develop this innovative technical solution, Valspar engaged in a holistic strategy, partnering with a range of NGOs, academics, toxicologists and brand owners, following this with extensive testing and an unconventional communication strategy.

Metal is the most versatile and lightweight food and beverage packaging material. Both aluminum and steel are easily recycled with no loss in quality. Coatings on metal cans are essential to preserving food and protect against corrosion, micro-organisms and off-putting taste.In North America alone, nearly 115 billion cans were consumed in 2014. In some major can segments, an estimated 40 percent of cans use non-BPA coatings now, and the market is expected to grow to over 60 percent within the next several years. With this rapid switch to non-BPA coatings, Valspar recognized the opportunity to bring effective, safe, thoroughly tested solutions to market.

Drug discovery, in reverse

We approached this challenge using Valspar’s Safety by Design process and by partnering with endocrine activity experts. Our goal was to design a molecule with the appropriate functionality of a bisphenol epoxy resin minus the undesirable biological activity associated with BPA.

With their expertise, we identified the key structural elements of bisphenols that enable the molecules to link to sites (estrogen receptors) in the body that are influenced by estrogen and estrogen-like chemicals. Knowing this, Valspar screened hundreds of theoretical structures to find a small set that wouldn’t be able to fit into the sites.

We then took this pool of chemicals and tested them for estrogenic activity and other hazards and further for regulatory agency clearances, manufacturability, sustainable supply chain availability, infrastructure compatibility and performance.

One monomer floated to the top: tetramethyl bisphenol F (TMBPF). TMBPF lacked estrogenicity, lacked genotoxicity and, due to the synthesis pathway of the final coating system, TMBPF will not migrate into food or beverages as BPA has been shown to do. Compared to BPA and BPA-based epoxy coatings the TMBPF monomer and TMBPF-based epoxy coatings have lower hazards and lower exposure. Win, win.

Inviting skeptics to prove us wrong

Valspar recognized the level of scrutiny from stakeholders that TMBPF, as a bisphenol, would invite. In addition to the partners who advised us in the first stages of this project, Valspar invited academics, independent research laboratories, brand owners and regulatory agencies and NGOs (some of whom were behind the BPA-free campaigns), to look at TMBPF and the resulting coating, the hazard and migration data we had generated, and asked them what additional data they would need to feel that this solution, if not perfect, was an improvement over the technology they opposed.

Valspar provided samples of the monomer, the oligomers (chemical structures comprised of multiple TMBPF molecules linked together), the polymer (a chemical structure comprised of multiple chemicals linked together) and the migrants from extraction testing, and asked these stakeholders to prove us wrong.

Stakeholder response

Valspar’s valPure non-BPA technology, including the V70-series coatings using the TMBPF epoxy resin, is approved for use in over 100 countries and can be found on over 20 billion cans in circulation today. The engagement from the NGO community proved to be a positive, productive relationship. Janet Nudelman, director of program and policy at Breast Cancer Protection Partners, offered the following comment on our process representative of the feedback we received: “It’s not just the new can lining that you’ve developed that we’re excited about, it is also your new proposed approach to safety testing which has the possibility of becoming a new industry standard.”

Janet Nudelman, director of program and policy at Breast Cancer Protection Partners, offered the following comment on our process representative of the feedback we received: “It’s not just the new can lining that you’ve developed that we’re excited about, it is also your new proposed approach to safety testing which has the possibility of becoming a new industry standard.”

Embracing transparency

Last, rather than claim this new molecule and coating as trade secret, Valspar thoroughly protected the intellectual property, which includes 49 patents. This allowed us to invite the public to review the data themselves by making the V70 polymer chemical identity and hazard data publicly available on Valspar’s website.

Safety by design

It was, admittedly, only after this process was complete that Valspar looked back and deemed this alternatives assessment process “Safety by Design.” This means evidence of absence of effects, not absence of evidence of effects. In this case, it means to demonstrate this new molecule does not have the same hazard profile as other bisphenol molecules.

It means collaborating with partners who think differently from us. It means being patient and ready to think outside of the box. “Safety by Design” is not the easy path. The V70 polymer took seven years and millions of dollars to develop. “Safety by Design” represents a valuable tool in the mainstreaming of green chemistry, and it means doing whatever it takes to develop a solution that safely will serve billions of people for generations to come.