Imerys Pigments, Inc.

Vince H Brown

Robert J Pruett

Jun Yuan

William L Garforth

A novel clay pigment, the manufacture thereof and the use of the pigment in the coating of lightweight groundwood paper are disclosed. The kaolin clay particles initially have a shape factor between less than 10 and a particle size distribution where between 30 to 60% by weight is less than 2 microns and 20% by weight is less than 0.25 micron e.s.d. This clay is subjected to attrition grinding to produce clay particles having a shape factor between 13 and 18 and then classified to produce a particle size distribution where 80 to 90% by weight are less than 2 microns and 20% by weight are less than 0.25 micron. These pigments have a G.E. brightness ranging from 88 to 92; are deficient in ultra-fine particles; are fluid at a high solids concentration greater than 70%, and have a low shear Brookfield viscosity below 500 cps and a high shear Hercules viscosity of 18 dyne-cm above 200 rpm when using an &ldquo;A&rdquo; bob.

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Sandersville, GA, United States of America

Vince H Brown