Polyols with it all
Reactive hot melt adhesive systems
Reactive polyurethane hot melts are produced by converting a mixture of different polyols with a surplus of a polyisocyanate component. This results in isocyanate-terminated prepolymers with an isocyanate content of typically 2 percent to 5 percent.
Reactive polyurethane hot melts combine the properties of regular or conventional hot melts with the advantages of chemically crosslinking adhesives.
In addition to improved temperature and creep resistance, they offer the following advantages:
- Nonsolvent formulations
- Moderate viscosity at application temperature
- Improved solvent and hydrolysis resistance
- Good adhesion to numerous substrates
- High bond strength
Covestro offers a broad range of raw materials for the production of these reactive polyurethane hot melts. Our product line covers:
Due to the relatively low vapor pressure and high application temperatures of reactive polyurethane hot melts (100 C – 170 C), a monomeric MDI or a modified MDI usually serves as the polyisocyanate component.
For specific applications, particularly when lightfast adhesives are required, we also offer a wide variety of raw materials based on Desmodur® aliphatic polyisocyanates.