Alternatives to Fluoro-based Additives in Coatings & Inks

 
"Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that have been widely used in coatings and inks due to their excellent properties such as water and oil repellency, chemical resistance, and durability. The environmental and health concerns associated with these additives have now led many coatings formulators to find alternatives to fluoro-based additives responding to the potential or increased regulations. Lack of availability of mainstream technology is also another major reason for many to seek alternates. Replacing an additive is never easy, and finding alternatives for fluoro-based additives can be particularly challenging. The fluorocarbon chain is namely both hydrophobic and oleophobic, which gives these multifunctional additives some unique properties that are difficult to replace. Fluorosurfactants for example are relatively low molecular weight additives containing fully (per) or partly (poly) fluorinated carbon chains connected to different functional groups. These additives are highly efficient at lowering the surface tension of liquid coatings to improve wetting of substrates and eliminate film defects. Within the wood coatings field, fluorosurfactants are established in water-based as well as solvent-based systems to solve wetting challenges caused by contaminations. In the end-applications of leather-, plastic-, and powder coatings, PFAS additives have been used to impart water- and stain resistance, durability, and other desirable properties. Hydrophobation effect supports water- and stain resistance for leather and plastic coatings particularly. Optical and haptical properties are essential for many household appliances covered by powder coatings. Formulators seeking alternatives to fluoro-based additives need to consider all the potential effects that these additives can bring to a formulation and then identify alternatives that can provide similar performance without the associated risks. Although a 1:1 replacement is often difficult, this paper will compare different additive families, structural-behavioral effects and review how these additives or combinations thereof can be used to replace fluoro-based additives in water-, solvent- and UV-based coating and inks systems. Overall, the use of PFAS in the end-applications of leather, plastic, wood and powder coatings is being phased out in favor of safer and more sustainable alternatives. While these alternatives may require some adjustments in coating formulations and production processes, they offer significant benefits in terms of environmental and human health."