“I have been working with a nylon based plastic with powder primers. Epoxy and acrylic urethane based powder coating appear to have great adhesion and chip resistance. The problem is moisture. Nylon will absorb small amounts of moisture over time. If I pre-bake the substrate (for as little as 5 min.@250F) the appearance is equal to powder primed steel. If I don’t pre-bake and the moisture content gets above a certain level, the result is mirco-porousity and popping across the entire surface. Since pre-bake is an extra step with an added cost, for many customers, this may not be an option. Is it possible for powder formulations to be adjusted for flow and cure? The ideal situation might be for the powder to stay “open” long enough so that the moisture has a chance to leave the substrate (during the powder bake) and not interfere with the powder during the cure phase.”
“The powder coating material you seek is referred to as an anti-outgassing formulation. This material will stay in a liquid state for a longer period of time when compared to standard powder coatings. During this liquid state, the part is allowed to outgas through the powder coating and then harden as the coating approaches final cure strength.
This material is more prone to sags (runs) since it stays softer for longer periods of time. Whether or not all your moisture escapes through the coating while the powder is in its liquid state can be proven by test.”