Versatile Pelletized Aluminum for Powder Coatings

By Jonathan Doll, Michael Venturini, Anthony Rohrer

To mitigate these issues, a process called bonding is often used to incorporate metallic pigments into a powder coating. During bonding, the powder coating is heated to just above its softening point and combined with effect pigments under moderate shear, causing the pigments to adhere to the surface of the powder coating. Such a process provides sprayed parts that have excellent pigment orientation, resulting in the best appearance for powder- coated articles.

In addition to their shape, aluminum pigments have certain chemical properties that impact their orientation in powder coatings. Aluminum pigments are typically made by ball milling a three-component system of aluminum grit, hydrocarbon solvent, and lubricant. For powder coating applications, the solvent is removed, but the lubricant stays behind on the surface of the pigment. Typical lubricants are saturated and unsaturated analogues of C18 fatty acids, namely stearic and oleic acid, respectively.