<VV> history of powder coating

[chris mann]

I came across this and thought it would be nice to share with my Corvair buddies...

The
concept of applying an organic polymer in powder form can be traced to
the late 1940s and early 1950s when powders were flame sprayed on
metallic substrates. During this time Dr. Erwin Gemmer,
a German scientist, developed the fluidized bed application for
thermoplastic resins on metal as a more efficient and faster
alternative to flame spraying. Here the powder is placed in a container
with a porous bottom and air is blown into it so the powder mix is
suspended in the air and turns into a fluid-like state.

 
Between 1958 and 1965, virtually all powder
coatings were applied by the fluidized bed process. Most applications
were functional in nature providing film thickness of 6-20 mils (around
150-500 microns). These thick film applications were generally for
electrical insulation, as well as for corrosion and abrasion resistant
purposes. Coating materials consisted of nylon 11, CAB, polyethylene,
plasticized PVC, polyester, and chlorinated polyether, among others.
However, thermoset epoxies (dicycandimide, or anhydride-cured) also
began to make an appearance during this period. Typical applications
included dishwasher baskets (PVC), motor iron insulation (epoxy),
marine hardware (nylon), and metal furniture (PVC, CAB), to name a few.In
1960, Pieter g. de Lange, a scientist in Amsterdam, began to research
non-polluting, environmentally friendly industrial coatings that could
compete with traditional liquid coatings. He focused on substitution of
solvents with air, which led him to the development of thermoset powder
coatings. He sought suitable solid resins, hardeners, pigments, etc.
and blended them together in dry form. The blend was then ground to a
suitable particle size. The fluidization technique used for fluidized
bed coating was used to create a "liquid" state in the material.
Electrostatic spray techniques were then adapted from wet paint
applications.

 
The commercial use of the electrostatic powder
spray (EPS) process was introduced in the U.S. and Europe around 1962
to 1964. EPS offered two major advantages. First, substrates could be
coated cold (no preheat). Secondly, the film thickness could be reduced
to 2 mils (50 microns). EPS is the most commonly used application in
the powder coatings industry today.

 
As powder coated finishes continued to gain
further acceptance, other issues involving coatings were coming to
light in Europe. These issues would affect the way the industry, as a
whole, would progress through the 1970s and into the present.

 
Source:

The Powder Coating Institute, "Powder Coating. The Complete Finisher's Handbook", Third Edition, 2004