Longer Pot-life

2K polyurethane coatings are supplied with the polyol, pigments, solvents and additives in one pack and the isocyanate in a second pack. Once these 2 components are mixed, the crosslinking reaction begins, causing an increase in paint viscosity in the case of solvent-based systems.

Spraying, rolling or brushing the coating is possible until the viscosity of the system becomes too high. It is an advantage for applicators to have a pot-life long enough to have sufficient flexibility in their work.

In 2K waterborne formulations, pot-life has to be measured by decrease of properties (such as gloss and chemical resistance), since viscosity increase alone is not a sufficient indicator.

Formulators often have to choose between a long pot-life and a short drying time. Improvement of aliphatic polyisocyanates now offers the possibility to get both performances.