Powder Coatings are “solid paint” which can be melted to form a continuous film over the substrate. Each powder particle contains resin, pigments, modifiers, extenders and curing agent, in case of thermosetting.
There are two types of powder coatings, thermosetting and thermoplastic.
Thermosetting Powder Coatings cross link and polymerize when heated and form a finished film. Once cured and crosslinked, this polymer network will not melt and flow again if heat is applied. The primary resins used in the formulation of thermosetting powder are epoxy, polyester, acrylic. In general, we refer to only thermosetting type of powder coatings.
Thermoplastic Powder Coatings are non-reactive and do not chemically crosslink upon application of heat but melt and flow over the part in the oven. The film hardens once part cools down and will remelt upon application of sufficient heat. They are polyethylene, polypropylene, nylon, polyvinyl chloride, polyester and polyvinylidene flurides/fluorocarbons.
WHY POWDER COATINGS:
Powder Coatings offer significant advantages over liquid solvent-based stoving paints:
- Ready to use. No stirring, mixing or thinning is required.
- Solvents free. No thermal afterburning of solvents is required.
- Virtually no VOCs or negligible emissions to the environment.
- Excellent durability and weathering properties
- Safety and low fire hazard
- Cleaner working environment
- High utilization. Efficiency recovery of oversprayed powder can enable utilization figures of over 95% can be achieved.
However, applicator should be cautious of contamination when changing colour. The utmost care is essential in cleaning the application equipment, spraybooth and recovery unit.
Powder Coatings are applied in custom job shops to large manufacturers. Metal, plastic, wood, composite and glass substrates can be coated provided that the curing temperature does not distort or deform the parts. Office Furniture, General Metals, Engine Parts, Light Fixtures, Industrial Shelving, Computer Cases, Toolboxes, Medical Equipment, Barbeque and Gas Grills, Appliances, Kitchen cabinets, Automotive components, Aluminium extrusions and sheets, Coil coating and Reinforcing bars for concrete, Valves and pipeline fittings and many other items can be successfully powder coated.