Primer of color coated board is the first coat applied on the surface of substrate, which is the basis of surface coatings. It mainly plays the role of anti-corrosion; in addition, it can also play the role of filling, repairing, sealing and so on. In
addition, the good adhesion of the primer makes the wall smoother, makes the topcoat easier to apply, and can reduce the use of topcoat. The most widely used primers are epoxy primers and polyester primers (polyester-amino primers and polyester-polyurethane
primers), in addition to water-soluble acrylic primers, these primers have their specific characteristics in addition to the common features mentioned above.
(1) Epoxy primer: It has good adhesion with the base plate, water resistance, alkali resistance and chemical corrosion resistance, but its flexibility is not as good as other primers.
(2) Polyester-amino primer: It has good adhesion and flexibility to the base plate, but it is more sensitive to humid environment and less resistant to chemical corrosion than epoxy primer.
(3) Water-soluble acrylic primer: good adhesion to the substrate, good flexibility, less organic solvents, low temperature curing, but not suitable for storage in humid environment, high requirements for pretreatment.
(4) Polyurethane (polyester-polyurethane) primer: good chemical corrosion resistance, friction resistance, durability and flexibility.