Types of powder coatings
There are two main categories of powder coatings: thermosets and thermoplastics. The thermosetting variety incorporates a cross-linker into the formulation. When the powder is baked, it reacts with other chemical groups in the powder to polymerize, improving the performance properties. The thermoplastic variety does not undergo any additional actions during the baking process, but rather only flows out into the final coating.
The most common polymers used are polyester, polyurethane, polyester-epoxy (known as hybrid), straight epoxy (fusion bonded epoxy) and acrylics.
- The polymer granules are mixed with hardener, pigments and other powder ingredients in a 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