Natural silicas in coatings

Silica extender pigments obtained from natural sources have been used in various coating systems for some time. A review of the microcrystalline silicas available to the paint formulator is included for reference purposes. Cost reduction and sheen control were recognised as attributes of ground natural silica. Properties of the finer or micronised natural silicas, such as lower pigment abrasion and low oil absorption, are covered to indicate potential contributions to the traditional or conventional as well as new coating systems.