The technology behind powder coating began in the laboratory and evolved into an industry with a worldwide reach.
The origins of powder coating are in the 1950s, with significant developments in subsequent decades that have led to its success as a method for coating various substrates.
The German scientist Erwin Gemmer came up with the concept of the fluidised bed process.
This was a process for thermosetting powder coatings that involved dipping metallic objects into a fluidised thermoplastic powder. The process enabled the powder to adhere and fuse to the surface.
Gemmer applied for a patent for this process and received it in 1955.
Fluidised bed techniques continued throughout the 1950s, involving pre-heating objects, dipping them into a churning container of powder, then heating the coated objects to finish them off.
Typically, these early thermoplastic polymer powder coatings were thick and inconsistent, but could be used for various practical purposes such as electrical and high corrosion resistance.
Between the late 1050s and mid-1960s, the fluidised bed process was dominant, until a major improvement occurred.
The thing that revolutionised the powder coating in the 1960s was the adaptation of electrostatic technology for applying dry powder coatings.
Already this method had been used for liquid paints, but now a French manufacturer developed the first electrostatic powder spray guns. The Swiss company Gema then developed their own version.
Electrostatically charged spray guns enabled a more consistent application of dry powder coating to surfaces.
This process applies positively-charged paint particles, which adhere to metal surfaces, even wrapping around components.
Coating materials first used in fluidised bed processes included nylon, CAB (cellulose acetate butyrate), plasticised PVC, polyethylene and polyester.
When searching for a suitable insulation material, Bosch developed a basic type of epoxy resin powder.
From the mid-1960s onwards, there was a development of the basic thermosetting resins that are still in use in powder coatings today:
Early manufacturing of powder coatings involved the production of relatively small batches in ball mills – rotating cylindrical vessels.
Ceramic balls in a slowly rotating chamber would crush the formula mixture by impact at a low rotation rate, over time periods up to 24 hours.
This process was slow, and yielded a primitive powder mixture, which could leave imperfect and inconsistent finishes.
Eventually, manufacturers developed more efficient and effective processes for manufacturing powder coatings, including blade mixing and then extrusion processing.
This latter process represented a revolution in manufacturing powder coatings, since it enabled the production of much larger batches through a continuous dry-feed process.
From the late 1970s onwards, the powder coating industry has grown globally.
Major industries adopted the process for a range of appliances. Advances in both resin technology and application equipment enabled the use of thinner and more decorative film coatings.
Coatings now included durable polyesters and chemically resistant powders.
From the 1990s, the automotive industry began to explore the possibilities of using powder coating as a body coat for vehicles.
This began with primer surfaces for small trucks and passenger vehicles, and evolved into clear topcoats for luxury cars.
With perfect smoothness a critical factor, these powder coatings had to be highly performing and exceptionally durable.
Powder coating application processes and powder coatings themselves have evolved to a stage where they are extremely versatile across a broad range of applications and industries.
Modern powder coating provides perfect finishes that are long-lasting, while cutting down on material costs involved in application and finishing. There is very little waste and even the air you use in the spray booth is returned directly to the plant, cutting down on heating and cooling costs drastically.
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