Modified zinc oxide-phosphate core-shell pigments in solvent-based paints

摘要

Purpose - The paper's aim is to focus on a new trend of pigments based on core-shell theory containing a core (bulk) of cheap oxides covered by a layer of phosphates. These new pigments combine the properties of both components besides being more economically feasible. Design/methodology/approach - Simple chemical techniques were used to prepare these pigments. Characterization of these pigments using X-ray diffraction and scanning electron microscopy was carried out. Evaluation of these pigments using international standard testing methods was estimated. These pigments were incorporated in solvent-based paint formulations based on medium oil alkyd resin. The physico-mechanical properties of dry films and their corrosion properties using accelerated laboratory test in 3.5 per cent NaCl for 28 days were tested. Findings - These pigments based essentially on zinc oxide covered with a surface layer of phosphates were easily prepared, are economically feasible and can successfully replace original phosphates with similar efficiency in their corrosion protection behaviour. Practical implications - These pigments can be applied in other polymer composites, e.g. rubber and plastics as reinforcing agent. Originality/value - The prepared pigments are environmentally friendly and can replace other hazardous pigments (e.g. chromates) with almost the same quality in their performance; also they can be used in other industries other than paints, e.g. paper, rubber and plastics composites.