In an industry driven by cost control and improved productivity, extreme care must be taken to maintain aluminum flake orientation to current or improved standards. High metallic “flop” is achieved when well- dispersed aluminum flakes exhibit in-plane flake orientation within a binder matrix that does not contribute to isotropic light scattering, or haze. Thus, achieving high flop requires both rigorous paint formulation and proper application. Colorimeters provide bulk-averaged color readings that are comprised of the summed contribution of many flakes. Lost in this analysis, however, is how individual flake orientation, local flake density, and interactions with the binder matrix contribute to these bulk color readings.
For this discussion, we will present a new method for quantifying individual flake orientation within a 3-dimensional volume of an applied basecoat film. This new methodology more accurately describes the contributions of each flake to the overall color impression and measured metallic flop. We have validated this technique by study of effects commonly known and understood by paint formulators and application experts. Ultimately, this technique provides quantitative, statistical route to analyzing flake orientation and distribution, allowing for improved formulating practices and paint application.
Dr. Matthew Irwin is currently a Formulation Scientist within the Axalta Research and Development group, located at the Global Innovation Center in Philadelphia, PA. He joined Axalta in August 2016 as a waterborne colorcoat formulator, and his work has focused on designing and characterizing high-performance coatings for automotive and industrial applications.
Prior to working at Axalta, Matthew obtained a Ph.D. in Chemical Engineering from the University of Minnesota, Twin Cities in 2016, with a focus on polymer physics and structure-property relationships in polymer blends. In 2011, he earned a B.E. in Chemical Engineering from Vanderbilt University.