Preservatives coatings: “Overall task will become more complex”
Scott Brown of Lonza explains the effect of regulations on the use of preservatives in the coatings industry and gives his assessment on the future.
How does the regulatory framework challenge the status quo of preservation in the paints industry?
Scott Brown: The status quo as regards preservation in the paint industry is that it is possible to achieve robust preservation with a sufficient dose of a preservative, but without triggering the requirement for problematic hazard communication phrases on the paint container label. The challenge posed by the regulatory framework is that fewer preservatives are available, and most of those that remain contain actives which attract hazard communication phrases if present above a threshold trigger level.
Against this backdrop, we have formulation trends in the coatings industry, such as the removal of co-solvents, which have led to coatings that are more susceptible to in-can spoilage. These formulation changes have created an upward trend on the preservative concentrations necessary for conferring robust preservation. The challenge to the status quo as regards preservation in the paint industry is the clash between the formulation-driven trend towards higher preservative concentrations and the regulatory-driven trend towards lower preservative concentration thresholds that trigger hazard communication.
Which specific challenge faces coating formulators when they are selecting preservation systems?
Brown: The challenge for coating formulators is to select a preservative that provides robust preservation without triggering the requirement for problematic hazard communication phrases. Hazard phrases can be problematic because they can alarm consumers and alter their buying patterns. The relevant hazard phrase in this context is primarily EUH317, followed by EUH208. A coating formulation which attracts the EUH317 phrase is also required to carry an associated GHS pictogram. No pictogram is required for EUH208.
Therefore, a consumer is more likely to notice the hazard communication associated with EUH317. A number of preservative systems in use today were selected so as to avoid attracting the EUH208 hazard communication phrase. However, many of the preservative systems selected to meet this criteria include MIT (2-Methyl-4-isothiazolin-3-one). In March 2016, the EChA RAC committee recommended lowering the EUH317 trigger concentration for this active from 1000 ppm to 15 ppm. If the RAC committee’s recommendation is adopted by EChA, then the coating formulator’s challenge will become even more difficult in the future.
What can the paint industry expect in this regard (preservation) in the future?
Brown: Given the adverse trends impacting the historically popular in-can preservative active agents, there is likely to be a re-evaluation of antimicrobial active agents from other use patterns. For example, the pyrithione active agents, which were traditionally used as fungicides, are finding increased use as co-biocides for in-can preservation. While it is likely that new preservative formulations will be introduced to address the emerging market need, it is also likely that the overall task of preservative selection will become more complex. The use of a single preservative across a paint company’s entire paint line will likely become less common, with an associated requirement for greater investment of time and money in preservative selection and testing.
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