Sherwin-Williams - Sustainable coatings for cans

It takes considerable expertise to develop new coatings for cans and metal bottles that guard against exterior damage and minimise internal corrosion. Tom Mallen, director global regulatory and strategic services packaging coatings at Sherwin-Williams, talks about the company's dedication to sustainability and the transparent engagement it has with stakeholders.

What advantages do coatings provide to metal can manufacturers?

Tom Mallen: There is an electrochemical reaction in interior food-contact coatings, where the metal surface of the can interacts with the food or beverage. The role of the coating is to inhibit or control this reaction between the metal and the food or beverage, in order to avoid corrosion and other undesirable electrolytic effects, even with the abuse that metal receives during part fabrication, welding, sealing, transportation and distribution, for example. The coating thereby enables the large-scale, high-speed and economical production of extremely safe food containers that can be filled with an enormous range of food products, which have valuable nutritional and sensory properties that are preserved throughout the item's long shelf life.

In regard to exterior can coatings, most of the same considerations are noted, and these also apply to interior coatings in varying degrees, depending on the type of can. The exterior of the can may be subject to less severe electrochemical attack but it experiences much more mechanical abrasion, which presents a physical integrity and aesthetic challenge for the can. The exterior coating protects the metal substrate from abrasion throughout the lifetime of the can, not only ensuring protection against damage, but also guaranteeing the pleasing aesthetics that are necessary for maintaining confidence in the choice of a metal food container by everyone in the supply chain, as well as consumers.

Why should beverage packaging companies choose Sherwin-Williams over other companies in the market?

From the very beginning of the product ideation process, our scientists and business groups are focused on developing a product that delivers superior productivity for our customers. This means that we not only create a product for the ideal film performance - which is, of course, very important - but our designs also cause minimal disruption in a coating application plant for coating switchovers, maximum application latitude, substrate-variation tolerance and line efficiency.

Furthermore, Sherwin-Williams has an excellent technical service group that has unmatched expertise in all areas of the light-metal packaging industry. Our engineers can be on-site for clients at short notice to ensure a smooth transition during the many phases of scale-ups. Sherwin's team is dedicated to making each transition an opportunity to delight the customer.

How important is sustainability to the group?

Our coatings are always designed with sustainability in mind. One of the lessons that history has taught us is that there are now more stakeholders involved in packaging coating selection and deselection decisions than there were five years ago. Valspar - which was acquired by Sherwin-Williams in June 2017 - recognised early on that clients, based on this change, would require coatings that not only deliver world-class performance, but also demonstrate marketplace longevity, depending on the pre-market acceptance by new stakeholders. Sherwin-Williams' attitude to several factors is also unprecedented in the industry, including its dedication to safety by design, and the material selection process for new product developments and transparency with stakeholders in relation to defining the criteria for BPA-replacement technology, as well as the company's determination to perform tests that are necessary for confirming if certain materials are sustainable replacements.

What changes will take place in the coatings side of the beverage packaging industry over the next few years?

We believe that the transition to sustainable and non-BPA coatings will continue. Sherwin-Williams has developed these coatings for all internal can coating applications, including cans and ends for beverages and food, as well as aerosol and speciality cans, caps and closures, tube and monobloc containers, and steel pails and drums. We also have developed a series of external can coating applications food and beverage containers. Sherwin-Williams will continue to lead in this area and consistently meet customer needs, consumer preferences and regulatory demands.