Method for evaluating the bond strength development of pMDI adhesive using ABES

Abstract The curing speed of adhesives is crucial in the production of wood-based panels. The Automated Bonding Evaluation System (ABES) is a commonly used method for evaluating the bond strength development of adhesives. However, using polymeric diphenyl methane diisocyanate (pMDI) with ABES can be challenging due to the significant moisture dependence required for proper curing. In this study, a simple and reliable method was developed to enable the use of pMDI with the ABES device. While the ASTM D7998–15 standard provided guidance, certain modifications were required to adapt the method to specific conditions. The results highlight several key factors that influence the curing of pMDI, including the addition of water, the need for higher pressure, and the preference for two-sided adhesive application. In addition, MDI emissions were monitored during ABES measurements and showed detectable but very low levels of emissions. This research opens up new possibilities for assessing the curing kinetics of pMDI adhesive.