TECHNOLOGY TO ENABLE POWDER COATING FOR PLASTICS; COMPOSITES; AND OTHER NONCONDUCTIVE SUBSTRATES

摘要

Powder coating is a recent, but increasingly fast gaining coating process in the industry today. Powder coating is preferred over liquid paints as it possesses strong adhesion, excellent durability, can be used on both textured or gloss surfaces, and it reduces the instance of runs and VOCs during application. Unlike conventional liquid coatings, powder coating does not require a solvent to keep the binder in a liquid suspension form. It's popular as it produces a high-specification coating, which is relatively hard, abrasion- resistant, and tough. The choice of colors and finishes is almost limitless, and the coating can be applied over a wide range of thicknesses. Primarily, there are two types of powder coating available - the first being thermoplastic powders that will remelt when heated, and thermosetting powders that will not remelt upon heating. The latter type of powder coating is more commonly used, where the powder coating is applied electrostatically (free-flowing, dry powder), and is then cured under heat to allow it to flow and cure into a beautiful and durable finish. It is during the curing process that a chemical cross-linking reaction is triggered at the curing temperature, which gives the powder coating most of its required properties. Powder coating of nonmetallic surfaces is possible, however the processes involved in manufacturing, high cost, and environmental limitations have reduced its usage. Additionally, regulations on painting have also become more strict, where there are more mandates seeking decorating materials that are less polluting.