Abstract: A method for the treatment of kaolin particulate material comprising: providing a dispersed aqueous suspension comprising kaolin particulate material and having a pH of at least about 7.5; selecting at least one selective flocculation polymer, wherein said at least one selective flocculation polymer has a measured anionicity ranging from about 1% to about 12%, such as from about 4.5% to about 8%; selectively flocculating said suspension into a first layer and a second layer by adding to said suspension said at least one selective flocculation polymer, and separating said first layer from said second layer.

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: The present invention provides high brightness kaolins exhibiting a Brightness (GE) of at least about 90.0. The hydrous kaolin pigments of the present invention may also have, inter alia, a steepness index (d30/d70×100) of at least about 39 and/or a titania concentration less than or equal to about 0.40% by weight of the pigment on a dry basis. (062) The hydrous kaolin pigment is produced by a process comprising: a) forming an aqueous suspension of a hydrous kaolin clay; b) forming a primary product by subjecting the suspension to classification or a combination of classification and griding; c), separating the kaolin from impurities by selective flocculation; and d) defining the separated kaolin. (063) The hydrous kaolins of the present invention allow coated papers to be produced at high brightness while maintaining acidic conditions on a paper machine. The invention pigmets exhibit brightness levels unexpectedly higher, e.g., about 2 to about 2.

Abstract: The present invention provides kaolin clay pigments having at least the following characteristics: Brightness (GE): at least about 89.0; Shape Factor: at least about 30; Brookfield viscosity, measured at 20 rpm and at less than or equal to about 65% solids: about 100 to about 700 centipoise; and Hercules viscosity, measured at 18 dynes and at less than or equal to about 65% solids: about 200 rpm to about 1000 rpm. Preferred kaolin sources include Brazilian kaolins, especially Rio Capim kaolins. The kaolin pigments of the present invention possess a combination of optical and physical properties, such as brightness, printability, and transfer efficiency, not previously seen in existing commercial products. They are useful, e.g., in paper filler and coating compositions, ink compositions, and printing applications, especially rotogravure printing.