Coil Coating is a process where rolled steel or aluminum bands are continually coated in big units. The special characteristic of coil coating is the ductility of the band after the coating step. This requires high flexibility of the coil and coating as well as an excellent adhesion of the individual layers.
The primer has to meet the following requirements:
- very high reactivity
- optimum adhesion to the substrate
- high flexibility
- long-term corrosion protection
The binder determines the primary properties of the system, but the fillers used can also exert an influence. This aspect has not found much attention in the past, which is why the following question needs an answer:
Are functional, high quality fillers as the Neuburg Siliceous Earth able to substitute the anti-corrosion pigment partly as well as the present filler and thereby maintaining the optical, mechanical and most notably the corrosion protective features?
This problem was studied in a polyester based primer formulation which contained 9.5 % anti-corrosion pigment and 5.7 % talc.
- small particle size
- excellent dispersion properties
- low sedimentation
- good leveling
- good adhesion
- good scratch resistance
- improved hiding power/opacity or partial replacement of titanium dioxide (top coats)
- partial replacement of corrosion protection pigments (primers and back coats)
- retention of good weathering resistance
- retention of good flexibility
- slight matting effect (depending on formulation and dosage)