[article]
| Titre : |
Powder coatings |
| Type de document : |
texte imprimé |
| Auteurs : |
Josef H. Jilek, Auteur |
| Année de publication : |
1997 |
| Article en page(s) : |
p. 91-94 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
The coatings industry has recognized the need and desirability to reduce energy consumption and solvent emission for many years. This led to the development of several new coating technologies which differed in their composition, application method, and curing mechanism from their traditional solvent-based counterparts. Examples are the development of novel epoxy resins for cathodic electroposition paints, the utilization of acrylated urethanes and epoxies in radiation curable coatings, and the production of oligomers with a narrow molecular weight distribution for high solid coatings.
Powder coatings, i.e., coatings made entirely from solid components, are also the result of this endeavor, although one of the first patents of a fluidized bed application was granted as early as 1955 in Germany. The pwder coatings of those days were relatively simple compared to today and consisted mainly of powdered thermoplastic polymers, like plasticized PVC or nylon. Later, the thermosetting, I.E, heat curable, powder coatings based on epoxy resins were developed which broadened the range of available materials but the application of the powders remained largely limited to the fluidized bed method. It was not until the early 1960s that the development of the electrostatic spray process provided the necessary breakthrough to make powder coatings a commercially viable alternative to conventional, liquid coatings.
It took another 20 years for thermosetting powder coatings to be established and to gain acceptance in the industry. During those years, significant improvements were made not only in the choice of raw materials like resins and hardeners, but also in the quality of equipment. This led to totally automated coating booths, providing more uniform powder delivery and application.
Today, thermosetting powder coatings are a rapidly growing, albeit small, segment of the industrial coatings market and their future is exceptionally bright. This is due to the fact that powder coatings are dry paints. They are 100% solid systems containing no solvents, thus little or no volatiles are given off during manufacture, application, and cure. Furthermore, the powder coatings process is predestined to be used in a fully automated fashion and little is wasted during application. Excess or oversprayed material can easily be recovered and recycled and rejects on the coating line are relatively few. Finally, high film thickness of up to 500 microns can be achieved in a single application and the resultant coatings exhibit excellent film properties. Overall, powder coatings offer an almost pollution free and highly aconomical way to coat a wide variety of metal substrates for either a decorative or functional purpose. |
| Note de contenu : |
- AREAS OF APPLICATION
- STARTING FORMULATIONS : Decorative interior applications - Decorative exterior applications - Functional applications
- FUTURE OUTLOOK AND CHALLENGES |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18294 |
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 69, N° 871 (08/1997) . - p. 91-94
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Powder coatings in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 69, N° 871 (08/1997)
