Due to technological advances, polyurea coating products are now available that can be applied directly to metal or concrete without a primer, achieving high adhesion in laboratory tests. However, given the complexity of most projects, matching primers remain essential.
Why Polyurea Coatings Need a Matching Primer
1. Clean After Cement Sanding or Metal Sandblasting
After surface preparation, dust inevitably remains. Applying a primer incorporates this dust into the coating as an internal filler. The dust on the bonding surface is the final challenge before construction—who can guarantee a spotless substrate on-site?
2. Seal Moisture in Concrete, Wood, and Other Porous Materials
Moisture is inherently present in porous substrates. One key role of the primer is to seal off this moisture, preventing it from interfering with the curing process of the polyurea coating.
3. Balance of Adhesion
On carbon steel, polyurea can achieve excellent adhesion even without a primer—sometimes better than with one. However, without primer, sandblasted carbon steel is prone to rust reversion. Therefore, applying a primer is recommended unless rust reversion can be fully controlled.
4. Enhancement of Concrete, Wood, and Other Substrates
The primer penetrates into concrete or wood, strengthening the substrate and significantly improving overall adhesion.
