Imerys Pigments, Inc.

Harry Vincent Brown, Jr

John Claude Husband

Christopher R L Golley

Daniel John Panfil

Robert J Pruett

Jun Yuan

David O Cummings

A pigment product suitable for use in a coating composition to provide a gloss coating on paper, the pigment product comprising a processed particulate kaolin produced from a naturally platy kaolin clay having a particle size distribution such that about 50% to 60% by weight of the particles have an esd less than 2 &mgr;m and less than 25% by weight of the particles have an esd less than 0.25 &mgr;m and a shape factor of at least 15. In processing, the crude kaolin is ground to a shape factor greater than 50 to produce even greater &ldquo;platy&rdquo; clay. The pigment product has a particle size distribution such that at least 80% by weight of the particles have an esd less than 2 &mgr;m and greater than 12% and less than 35% by weight of the particles have an esd less than 0.25 &mgr;m and whose surface area is greater than 12 m /g when measured by the BET method.

Kaolin pigments, their preparation and use

A paper coating pigment manufactured from kaolin crude containing minor amounts of minerals is used in lightweight coated and ultra-lightweight coated applications. The pigments comprise a phyllosilicate assemblage of minerals that yield a final pigment MgO content ranging between 0.04 to 0.3 weight percent and a K O content ranging between 0.12 and 0.8 weight percent based on the dry weight of the kaolin crude. The mica in the pigment product is 1.0% to 6.7% by weight, and smectite is 1.2% to 9.1% by weight of the kaolin. The presence of these weight percentages can be identified by a shape factor of 15 or greater. The viscous clay content of the feed to produce the pigment product is between 70 and 100 weight percent based on the dry weight of the kaolin clay. The pigment has a shape factor ranging between 35 and 60 or greater, and greater than 80% by weight of the particle are less than 2 microns, and greater than 12% are less than 0.25 microns.

Kaolin clay pigments, their preparation and use

A pigment product suitable for use in a coating composition to provide a gloss coating on paper, the pigment product comprising a processed particulate kaolin produced from a naturally platy kaolin clay having a particle size distribution such that about 50% to 60% by weight of the particles have an esd less than 2 &mgr;m and less than 25% by weight of the particles have an esd less than 0.25 &mgr;m and a shape factor of at least 15. This platy clay can be blended with b-fraction clay component. In processing, the crude kaolin is ground to a shape factor greater than 50 to produce even greater &ldquo;platy&rdquo; clay. The pigment product has a particle size distribution such that at least 80% by weight of the particles have an esd less than 2 &mgr;m and greater than 12% and less than 35% by weight of the particles have an esd less than 0.25 &mgr;m and whose surface area is greater than 12 m /g when measured by the BET method.

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Sandersville, GA, United States of America

Harry Vincent Brown, Jr