FDCA-based polyester resins for sustainable coil coatings

 
"2,5-Furandicarboxylic acid (FDCA) is emerging as a sustainable alternative to fossil-based phthalic acids in polyester production, offering significant environmental benefits. The recent commissioning of the first large-scale FDCA flagship production plant marks a milestone in its commercial application in packaging and coatings. This study explores the use of FDCA as a bio-based building block in polyester resins for coil coatings. These coatings, applied in thin layers on metal substrates, are present in several applications such as building and architecture, home appliances, and packaging. The coatings must exhibit excellent chemical, mechanical, and UV resistance, and for food contact applications, they must meet stringent regulatory standards. This research was aimed to develop at least partially bio-based resins for coil coatings by substituting tere- and iso- phthalic acid with FDCA in our standard polyester formulations. The target was to achieve comparable performance between the bio-based resins and their synthetic counterparts. 1-41% FDCA content per polymer resins were synthesized and evaluated in coil coating primer. The FDCA-based resins demonstrated properties that met market standard resin and coating in most properties. However, as FDCA content increased, issues such as discoloration and solvent incompatibility arose, along with impacts on the molecular weight of the resins. While FDCA negatively affected the gloss of the primer, it did not impact the gloss of the final coating system. FDCA-based polyesters offer a promising environmentally-friendly alternative, reducing the product carbon footprint by up to 50% and positively influencing other Life Cycle Assessment (LCA) parameters. *This study an upgrade from the results published in European Coatings Journal in April 2023 and in Farbe und Lack issue July/August 2023. "