Most polyurethane-based reactive hot melt (RHM) adhesives contain free monomeric diisocyanates, which depending upon their chemical nature, can be hazardous to users when not handled in a safe manner. As of August 2023, the European Authorities under REACH will adopt a stringent labeling requirement and mandatory training for all users of adhesives containing >0.1% of residual monomeric isocyanates. To be ready and address multiple customer concerns in the region, H.B. Fuller has invented a unique, patented approach to achieve RHMs containing <0.1% free monomeric diisocyanates to be used in key markets. Compared to other low monomer RHMs developments, this improved approach leverages economic-wise, commodity raw materials instead of single-sourced, expensive raw materials. It also supports conventional RHM production equipment. H.B. Fuller has been using this route to convert most of the company’s RHM portfolio into the new low monomer versions. These were found to be more sustainable, contributing to lower hazardous emissions, and showed higher initial strength and excellent application stability relative to their conventional counterparts, while also being more cost effective. Currently, these formulations are being used for woodworking applications, but the potential is huge and further developments are already underway for automotive, graphic arts, and electronics.
Co-authors: Daniel Van-Dyke, Matthias Gurr, Annett Linemann, Iñaki Sigler