What Does Thermoplastic Coating Mean?
A thermoplastic coating is a coating that does not react chemically during drying. Rather, the coating is "fused" to the substrate using heat. Thermoset coatings are usually available in powder form. The coating particulates or the metal's surface is first heated to the desired temperature. The subsequent cooling process then causes the coating to harden and gain strength. One of the most defining characteristics of thermoplastic coatings is their ability to be reheated, remolten and resolidified.
Corrosionpedia Explains Thermoplastic Coating
Because thermoplastic coatings can be reheated without any significant changes to their composition or strength properties, they can be reprocessed and redistributed along the surface. This allows coating applicators to remove flaws that may have developed during the initial application. Non-thermoset coatings, on the other hand, burn when reheated and, therefore, cannot be reprocessed and reapplied.
Some of the most common methods of applying thermoplastic coatings include:
- Electrostatic spray application – The powder coating is electrically charged and is attracted to the metal's surface. The dry film and the coated material are then heated in an oven, causing the powder to melt and flow.
- Preheat spray application – The metal part is preheated, and the powder coating is applied through a spray nozzle. The dry coating immediately melts and flows upon coming into contact with the heated surface.
- Fluidized bed application – Preheated parts are immersed in a hopper with a fluidized thermoplastic powder coating. The powder coating is attracted to and subsequently fuses to the heated surface. This method is also known as thermoplastic dip coating.