| Abstract:The migration of latex particles to the coating surface during consolidation was investigated, and a new mechanism based on Einstein classical particle diffusion theory and surface trapping effect was proposed to clarify the controversy in coating and related fields. X-ray photoelectron spectroscopy (XPS) technique was used to determine the elemental composition and content at the surface of coating comprised mainly of micron sized kaolin clay and sub-micron sized styrene butadiene latex, and regression equation was established between surface atomic concentration and latex amount in the formulation. By converting the surface XPS results of coatings dried under various conditions to latex content using the above equation, the effect of various factors on the degree of latex particles migration was analyzed quantitatively for the first time. The results showed that latex migration to coating surface can be promoted by increasing drying temperature and drying time, and decreasing the initial solid content of coating colors, while impeded by raising its particle size, the substrate absorption, initial solids content and viscosity of coating colors, and therefore the new mechanism was verified. |
