NEW WATER-DISPERSIBLE SILICA-BASED PIGMENTS - SYNTHESIS AND CHARACTERIZATION

Water-dispersible pigments were prepared by grafting reactive dyes to the surface of derivatized silicas. The silica core consisted of either fumed hydrophilic silica with surface areas of 200 or 380 m2g-1 or monodisperse spherical silica ranging in diameter from 40 to 500 nm. The silica surface was derivatized with silane coupling agents, such as aminopropyltriethoxysilane (APS) and N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane (BHAPS). The coloration proceeded on suspensions of the derivatized silica in water in the presence of a soluble reactive dye. The resulting brightly colored pigments were characterized by particle size analysis and visible absorption spectroscopy. © 1990.