Use of standing wave ultrasonic atomisation in painting technology

The prototype installation developed for the production of powder coatings from melted polymers has achieved the trouble-free atomisation of thermoplastic, duromeric and pigmented polymer resins. The globular powder coating has shown improved pourability, fluidisation properties and stability in storage. In comparison with a conventional laboratory grinder, specific energy consumption has been significantly lower.

To date, the production of homogeneous powder coatings from melted polymers for use in painting has required the use of expensive process technologies for primary crushing, milling, rolling and cooling.  Powder production by the use of standing wave ultrasonic atomisation technology offers a potential alternative.  This technology has already been successfully applied to molten metals, glass and wax.

Under these conditions, basic investigations have been undertaken into the transferability of this technique to melted polymers, and a prototype installation for the production of thermoplastic and duroplastic powder coatings has been developed.  By this method, conventionally mixed melted powder, which has been homogenised in an extruder, is atomised into fine powder particles in an ultrasonic field.

This project has also involved the identification of appropriate reactive thinners for the reduction of powder viscosity, together with the investigation of the direct application of the resulting powder coating to the object to be painted.


Results:

• Standing wave ultrasonic atomisation technology has been successfully transferred to melted polymers, and has been optimised for the specific material and process parameters of powder coating.  Thermoplastic, duromeric and pigmented polymer resins have been atomised with no problems.
• In comparison with a conventional laboratory grinder, specific energy consumption has been significantly lower.
• The globular powder coating produced by standing wave ultrasonic atomisation has shown improved pourability, fluidisation properties and stability in storage.  In the application of the powder coating, a higher optical surface quality is anticipated.
• Reactive thinners investigated to date have proved to be unsuitable.   Oxazolines and oxazines are considered to have substantial potential.

Bezugsquelle: The final report (call number F 00 B 384, in German) can be borrowed from:

Technische Informationsbibliothek (TIB) Hannover

Welfengarten 1B
30167 Hannover




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