The History of Powder Coating
Although many archaeologists claim that the earliest painted art forms can be seen in the Stone Age cave paintings, at Lascaux in Southern France and Altamira in Northern Spain,
Known as the Bradshaw paintings, they’re believed to be up to 60,000 years old – which is at least five times older than the Egyptian pyramids.
According to Indigenous legend, the paintings – discovered by Joseph Bradshaw in 1891 – were created by birds using their tail feathers. These paintings show extraordinary sophistication and are widely considered to rank in archaeological significance with Nefertari’s tomb in Egypt.
Closer inspection of these art forms, may well include paintings with bird tail feathers, however as can be seen, the background colouring of these art forms contain colour graduations. As with the earliest aboriginal art of handprints,
these effects were achieved by blowing pigments, typically Iron Oxide red or yellow, [known as ochres] or sputtering pigment / water mixtures over the held object (boomerang) or hand to create a reverse image.
Similarly, the sandstone blocks of Kakadu and Arnhem Land house a supreme collection of rock art. Kakadu itself contains one of the greatest concentrations of rock art sites in the world. Approximately 5000 art sites have been recorded and a further 10,000 sites are thought to exist. The rock art sites are concentrated along the escarpment, in gorges, and on rock outliers. Many of these sites are large and contain many layers of paintings.
The paintings, estimated to range in age from 20 000 years to the recent present, constitute one of the longest historical records of any group of people in the world. The rock art sites of Kakadu are recognised internationally for their cultural value and are one of the reasons that Kakadu is inscribed on the United Nations list of World Heritage properties.
However, what is not often realised is that both of these locations actually house the earliest powder coatings ever produced.
In the modern world, it was Erwin Gemmer of Knapsack Griesheim AG (later to be acquired by Hoechst AG) that developed the first powder coating process, back in 1952. Gemmer’s german patent (DE Pat 933,019) was for a hot dip fluidised bed coating, a technique that is still used to this day for high build corrosion or electrical resistant coatings.
In 1961, Shell Ltd developed the first thermoset coating technology and in the same year Ransburg Electrocoating Corporation (later Ransburg Gema, now ITW Gema) developed the world’s first electrostatic spraygun.
Between 1958 and 1965, virtually all powder coatings manufactured were used for functional applications such as electrical insulation, corrosion and abrasion resistance. They typically had film thicknesses of 150 µm to 500 µm, and were applied by means of the Ransburg fluidized-bed application. The coating materials used in those days were based on the thermoplastic resins of Nylon 11 for boat accessories, Cellulose Acetate Butyrate (CAB) 3 for metal furniture, Polyethylene (PE) and plasticized PVC for dishwasher baskets and to a lesser extent, Polyesters and Chlorinated Polyethers. At the same time, Bosch developed the first thermosetting epoxy resin powder in their search for a suitable electric insulation material.4