Adhesive experts from Huntsman have developed an aromatic polyurethane prepolymer that can improve the manufacture of reactive hot melt (RHM) adhesives. Suprasec LM 4702 prepolymer allows adhesive formulators to create bonding solutions with a free diisocyanate monomer weight content of below 1% - the threshold where H351 hazard or R40 risk labelling comes into effect. The solution is ideal for the creation of RHM adhesives for book binding; box production; sports wear manufacture; the creation of automotive interior parts; and the edge banding and profile wrapping of items of furniture such as kitchen cabinets and work surfaces.
Conventional polyurethane-based RHMs are typically produced by converting a mixture of polyester-based polyols with a surplus of a diisocyanate component. The RHM produced is isocyanate-terminated with a final NCO-content of between two and four per cent. Replacing pure MDI with Suprasec LM 4702 prepolymer has minimal impact on other processing parameters – meaning RHMs remain easy to formulate and can be processed using industry standard methods and raw materials.
Suprasec LM 4702 prepolymer will be unveiled by Huntsman on the first day of Feica - the European Adhesives and Sealants Conference. At the event, Dr. Servaas Holvoet, Technical Manager for Adhesives and Coatings at Huntsman, will present a paper focusing on the use of prepolymers in the creation of PUR adhesives, and the environmental, health and safety benefits that can come with designing low monomer polyurethane resins.
