Binder and Crosslinkers for UV Powder Coatings
The most suitable approach for a coating formulation is the use of a major binder and a crosslinker. The cross¬linker may control the network density for the coating, while the binder determines properties of the coating such as discoloration, outdoor stability, mechanical properties, etc.
Furthermore, this approach will lead to a more homogenous concept in the powder coating applications as a category bringing similitude to thermosetting coatings where crosslinkers such as TGIC and hydroxyl amides are used. A crosslinker should present properties quite specific for the application intended: molecular weight; high functionality; and physical properties compatible to the application.
Crosslinkers for UV-coating powders must somehow match the properties of the above-mentioned crosslinkers used for thermosetting powder coating. We have synthesized and studied the crosslinking performance of three acrylic and one allyl derivative, suitable for UV powder coatings.