The film formation of waterborne epoxy coatings is more rigorous than that of solventborne epoxy coatings because there are two steps in the process:
Water volatilization and paint film polymerization and crosslinking. If the curing rate is slower than the evaporation rate of the water, the film will contain water and the performance will be reduced. This makes the control of temperature, relative humidity and ventilation during application more important than solvent-based epoxies.
During construction, the relative humidity should not exceed 85%, preferably below 65%. Excessive relative humidity will delay the volatilization of water. During the evaporation of water, the epoxy resin and the curing agent undergo a cross-linking reaction. When the evaporation speed of water is faster than the curing speed, the paint film does not contain water. If the evaporation speed is slower than the curing speed, the paint film will contain water and become affect the performance of the paint film.
