The excellent properties of epoxy coatings relative to corrosion protection make them the polymer type of choice in many applications. They wet metal surfaces very well and show a tolerance to water and humidity. 2K
Epoxy coatings employing a modified cycloaliphatic amine such as EC 423 will cure on a substrate in the presence of water and high humidity. The basis for good wet adhesion is due to the high rigidity of the thermoset epoxy and the bonding groups of the binder network interacting with the substrate surface. The interaction withstands under creepage of water to provide a lateral barrier effect.
The excellent wet adhesion and corrosion protection of epoxy coatings exhibit themselves in thin primer coatings as well.
Since the gel point of the 2K epoxy coating is reached only after an extensive crosslinking period, most of the volume shrinkage occurs during this time. Any remaining shrinkage after the cure period is not critical.
Epoxy coatings are free of internal stress due to this cure cycle phenomenon. This cure process accounts for the outstanding adhesion compared to other binder systems.
Epoxy coatings are further enhanced by anti-corrosive pigments such as Zinc Phosphate and barrier pigments such as Micaceous Iron Oxide and Mica.