Polyurethane raw materials for thermoactivated adhesives are water- and solvent-based. Adhesives are applied in liquid state. After drying, the polymer film is normally not sticky at room temperature.
It is worth noting that at elevated temperatures, the molten polymer film is sticky and suitable for connecting substrates. For solvent-based adhesives, the Desmocoll range is offered, consisting of 25 products with different crystallization trends and molecular weights. Desmodur R crosslinkers are available for the formulation of exceptionally durable 2K adhesives. Water-based adhesives can be formulated with the Dispercoll U product range, which includes 14 degrees with different crystallization and melting behaviors.
Desmodur D or Bayhydur water-dispersible isocyanate crosslinkers can be added to formulations to improve heat resistance and bond durability. 1K water-based polyurethane adhesives can be formulated using latent reactive isocyanate crosslinkers or, with selected Dispercoll U grades, using a polycarbodiimide crosslinker.