Sustainable repair: A novel healable PU wood

 
A waterborne polyurethane with assisted healing technology was developed for high performance wood coating applications. The novel healable coating can recover physical damage upon exposure to heat, moisture, or solvents via reversible hydrogen bonding aided by a polyamide soft segment. The coating was developed to provide an optimal balance between performance and recovery. The technology is suitable to be implemented in exterior and interior wood coatings with protective features comparable to commercially available high performance waterborne coating systems. Test methods were developed to study the film recovery process to accurately assess the balance between the self-healing and the protective features of the resin. The novel resins were studied for convenient and easily accessible trigger mechanisms in various formulations. We found that the best results can be achieved using isopropanol solutions, but the recovery is significant when submitted to elevated temperatures and in high humidity environment as well, and the recovery-performance balance can be modified by simple formulation changes. The resin was designed for environmentally compliant coating applications with ~20% renewable carbon content for low volatile organic content (VOC) formulations (< 17 g/l, ISO 11890-2).