Hello fellow formulating chefs. Today’s lesson is on selecting the proper spices to make that perfect powder coating formula. All good chefs start with basic staples to enhance the taste of any dish. In the cooking world nearly every recipe requires a little salt and pepper to bring out the flavor of everything from a nice cut of beef to starches and fresh vegetables. It is no different in the powder coating world, as we employ a myriad of spices and flavorings or in simple formulators’ parlance, additives.
As salt and pepper are common staples used in nearly every recipe, powder coating formulations require a flow agent and degassing agent. The purpose of flow modifiers (aka flow agents) is to normalize the surface tension of the molten film with the substrate and ambient air as the coating melts and flows in the oven. Without them most powder formulas will yield a cratered surface. This phenomenon isn’t due to environmental contamination, but from the diversity of polymeric and oligomeric components in the formula. The flow agent provides “controlled incompatibility” of the various binder components, so they flow together. Resins do not possess a monodispersity of molecular weight, and crosslinkers and other additives may have a significant difference in surface tension compared to the base resin. Hence, sprinkling a little flow agent into the mix is necessary.