Minimum ignition energies of coating powders for the electrostatic powder coating process

The minimum ignition energies (MIEs) of more than 40 coating powders were determined. It turned out that the MIE depends on the particle size distribution or the specific surface area of the powder calculated from it, the chemical substance group of the resin used, the powder agglomeration and the resin content. Minimum values of 1.7 mJ resulted for transparent epoxy coating powders (d 50 · 25 μ m). The evaluation of the results from the point of view of safety showed that no hazardous situation will arise when these powders are properly sprayed using hand-held spray guns tested according to EN 50 050.