Powder coating is a type of coating that is applied as a free-flowing, dry powder. The ” main difference between a conventional liquid paint and a powder coating is that the powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form. The coating is typically applied electrostatically and is then cured under heat to allow it to flow and form a skin. Powder coating is mainly used for coating of metals, such as household appliances, aluminum extrusions, drum hardware, and automobile and bicycle parts. Types of powder coating There are two main categories of powder coating: thermosets and thermoplastics.
The most common polymers used are Polyester, Polyester-Epoxy (known as hybrid), Epoxy and Polyurethane, Production:
- The polymer granules are mixed with hardener, pigments and other powder ingredients in an industrial mixer.
- The mixture is heated in an extruder
- The extruded mixture is rolled flat, cooled and broken into small chips
- The chips are milled and sieved to make a fine powder
The powder coating process
The powder coating process involves three basic steps:
- Part preparation or the pre-treatment
- The powder application
- Curing
What are the advantages of using Powder Coating instead of other coating treatments?
- Powder coatings emit near zero volatile organic compounds (VOC).
- Powder coatings can produce much thicker coatings than conventional liquid coatings without running or sagging,
- Powder coated items generally have fewer appearance differences between horizontally coated surfaces and vertically coated surfaces than liquid coated items.
- The wide range of specialty effects are easily accomplished using powder coatings that would be impossible to achieve with other coating processes.