When considering coating plastics, the first obvious question pops up. Why bother? By simply using pigmented resin one gets a molded-in color that can't scratch off and one that also eliminates the need for a finishing operation. The answer is two-fold. One is that, in thick, large plastic parts, it can be more economical to put color on the outside where it is needed, instead of throughout the entire thickness of the part. The other is better color matching. Everyone has had the experience of seeing an assembly of metal and plastic parts that didn't perfectly match, and where the fading on the plastic only made the color mismatch worse over time.
Traditionally, those taking the coating route for coloring plastic parts had only one option - liquid coatings. The desire to powder coat plastic parts was but an unfulfilled dream. Even though the powder coating of metals was a proven and growing technology, the obvious challenges of putting powder on plastic restrained this approach.