September 28, 2021
Binder systems have the most influence on coloristic properties of carbon black in powder coatings, according to a study by Orion Engineered Carbons.
The new research was conducted using carbon black in an epoxy-polyester hybrid and polyester system with HAA and TGIC crosslinkers.
“Based on the study results, we recommend high-color furnace black or high-color gas black for applications requiring high jetness with bluish undertone,” says Trinh Nguyen, Technical Market Manager at Orion.
“We recommend low to medium furnace black for applications requiring low to medium jetness, and coarser grades such as regular furnace black or lamp black for tinting applications,” she adds.
For typical powder coatings, Nguyen recommends using one to two percent loading of carbon black (by weight, on total formulation) to obtain an opaque appearance. Bead and powder forms of the same carbon black grade showed no differences in colorimetric performances of the system.
The Orion study showed that in the hybrid system, the oxidized gas black had inferior coloristic performance to non-oxidized types. In the polyester/HAA system, the non-oxidized gas black provided better pigment stabilization than the oxidized type.