Classical thermoplastic hotmelt adhesives liquefy when heated. They crystallize and produce an adhesive bond during the subsequent cooling process. Very fast initial bonding is a typical property of hotmelts. For the production of classical hotmelt systems Bayer MaterialScience supplies a line of hydroxyl polyurethane hotmelts under the Desmomelt® trade name, which is available as a solid powder.
Bayer MaterialScience also offers raw materials for the formulation of reactive polyurethane hotmelts. These adhesives contain 2-5% isocyanate groups and therefore they show an additional chemical crosslinking in ambient humidity. This increases the resistance to temperature, hydrolysis and solvent of the finished product significantly. Typical raw materials of this category are the low-monomer MDI-polyisocyanates (like Desmodur® 44 M), polyesters (like Baycoll® AD 5027), polyethers (like Desmophen® 1262 BD), as well as specific prepolymers for the formulation of low-emission reactive polyurethane hotmelts (Desmodur® E XP 2715).
The final properties and process performance of both hotmelt systems can be modified by adding suitable aliphatic or aromatic polyisocyanates.
Typical applications are the sole bonding in the footwear industry, adhesives for the packaging industry, for bookbinding, for the textile industry or the electronic industry (bonding of metal coils), just to name a few. Other applications are possible as well. Please contact our adhesives experts for additional information.
