Powder coatings are solvent-free enamels manufactured using a 3-step process (Powder coatings production). The powder coating is applied to the part or component by electrostatic spraying equipment or in a tribostatic process. In a subsequent curing process, the powder coating is melted and chemically cross-linked at substrate temperatures of 302 to 392 °F (150 to 200 °C).
The success story of powder coating begins with industrial surface finishing in the 1960s (History of powder coating) and continues to develop as the technology has many advantages:
- No solvents
- Virtually 100% material utilization
- Easy to process and clean
- Applicable on many substrates
- Protective and decorative
- TIGER Drylac® offers the most comprehensive range of standard colors and effects.
TIGER Drylac® powder coatings are solvent-free coating materials consisting of different synthetic resin systems, pigments and special additives for high quality surface finishing. The basic materials for powder coatings are processed into a fine coating powder in a 3-step production process: premixing, extrusion and milling. Depending on subsequent use, the powder is set to a predefined particle distribution.
In contrast to liquid paints, powder coatings do not contain solvents. Powder coatings are applied to parts by electrostatic spraying equipment or in a tribostatic process. In a subsequent curing process, they are melted and chemically cross-linked at substrate temperatures of 302 to 392 °F (150 to 200 °C).
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 metal 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 (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 paints. 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.A. 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.
- Association of the Austrian Chemical Industry, ‘Unser Lack und seine Zukunft’ (Our Coating and Its Future).
- Principles of Powder Coating ‘Grundlagen der Pulverbeschichtung’, Edition, March 1991; updated 2 C. Herrmann, April 1999, internal training documents, TIGER Coatings GmbH & Co. KG.
- The Powder Coating Institute, ‘Powder Coating. The Complete Finisher's Handbook’, Second Edition, 1999.
- Industrial Powder Coating, ‘Industrielle Pulverbeschichtung’, J. Pietschmann, JOT reference, October 2002, p. 1
- Industrial Powder Coating, ‘Industrielle Pulverbeschichtung’, J. Pietschmann, JOT reference, October 2002, p. 1, updated.
- Industrial Powder Coating, ‘Industrielle Pulverbeschichtung’, J. Pietschmann, JOT reference, October 2002, p. 2.
- BASF Coatings Technology Manual ‘BASF Handbuch Lackiertechnik’, A. Goldschmidt/H. J. Streitberger, BASF Coatings AG, Münster, Vincentz Verlag, p. 596, 2002; partially updated.