Лако-красочные материалы — производство

Generally, pure liquids do not foam, but coatings, being multicom­ponent systems, may produce foam. When air is introduced into a liquid coating, bubbles are formed, which rise through the liquid to the surface. Upon reaching the surface, liquid from the bubble wall starts to drain under gravitational force and it becomes thinner. If the liquid is pure, the bubble will burst as soon as it reaches the sur­face and no stable foam is formed. If the liquid contains surfactants, a stable foam can be formed. The stabilization of foam results from two effects across the foam lamella: the electrostatic repulsion effect and the Marangoni effect.