Using Small Particle Spacers to Enhance TiO_2 Hiding Performance

摘要

Small (nano-sized) extender particles have often been presented as having the ability to increase the scattering efficiency of TiO_2 pigment by providing a buffer between pigment particles. This keeps the particles separated and prevents the well established loss in opacity due to particle-particle crowding. Often the claimed increase in opacity is quite substantial - claims up to 40% improvements have been made. In this paper we consider the mechanism of increased scattering efficiency and evaluate the results for various small particle extenders. In addition, we discuss which classes of extender particles are the most effective at improving TiO_2 scattering efficiency and place an upper limit on the extent of improvement possible.