Natural and synthetic indigo - application in cosmetologyZygmunt Boruszczak Instytut Technologii Polimerów i Barwników, Politechnika Łódzka Summary A new method of indigo pigment preparation was developed. Its preparation involved the reduction of a natural or synthetic indigo with thiourea dioxide in water environment and subsequent oxidation of the resulting leuco-compound by exposure to air in the presence of talc. The fundamental properties of the composite pigments were studied. It was found that new composite pigments exhibit an excellent resistance to functional fluids and organic solvents, good resistance to sunlight and are easy dispersible in various media and adhesives. The resulting pigments were classified into the group of coloring agents that are friendly to human beings and the natural environment, with an indication for use in color cosmetology. Key words: indigo, cosmetic pigments, composite pigments |