Abstract: A pigment product for use in a coating composition to provide a gloss coating on paper, the pigment product comprising a processed particulate kaolin having a particle size distribution such that at least about 80% by weight of the particles have an equivalent spherical diameter less than about 2 p,m and in the range of from about 10% to about 20% by weight of the particles have an equivalent spherical diameter less than about 0.25 wm, the particles have a shape factor in the range of from about 20 to about 36 and the particles have a particle steepness in the range of about greater than about 35, more preferably in the range of about 35 to about 40, and wherein the kaolin is derived from a secondary kaolin source.

Abstract: There is disclosed a process for preparing a filler composition suitable for incorporation in a polyester film-forming material, which process comprises the following steps:(a) calcining a crude kaolin clay under conditions such that the calcined product comprises particles consisting of aggregates of fine kaolin platelets;(b) suspending the calcined clay product from step (a) in water containing a dispersing agent for the calcined clay, so as to form a suspension containing from 40% to 70% by weight of dry calcined clay;(c) subjecting the suspension formed in step (b) to comminution by attrition grinding with a particulate grinding medium for a time sufficient to reduce the average diameter of the aggregate particles to within the range from 0.3 .mu.m to 0.9 .mu.m, and to ensure that the calcined clay is substantially free of particles having an equivalent spherical diameter larger than 5 .mu.