Performance control of polyether based reactive hot melt adhesives

Polyurethane reactive hot melt (RHM) adhesives are finding utility in high performance hot melt applications where superior green strength and ultimate thermoset properties are required. Commercial reactive hot melt resins are typically pure MDI (Methylenediphenyl diisocyanate) prepolymers of adipate-based polyester polyols. The purpose of this study was to determine the feasibility of using an all polyether polyol-based isocyanate-terminated prepolymer in RHM adhesive formulations. The RHM adhesive performance of polyurethane prepolymers prepared with MDI and polyether polyols was tested specifically for initial viscosity, green strength, tack free time and melt stability. The results demonstrate that it is possible to produce polyether polyol-based polyurethane RHM adhesives with performance comparable to those obtained from polyester polyols.