Imerys Pigments, Inc.

Ecc International Limited

Imerys Minerals Limited

William L Garforth

Robert J Pruett

Jun Yuan

Anthony V Lyons

David O Cummings

Steven M Fortier

Daniel John Panfil

David Robert Skuse

Gary F Matz

Dickey S Shurling

Christopher R L Golley

Michael J Garska

Christopher Nutbeem

William H Pope

Rajan R Iyer

Anthony Allan May

Shih-Ruey Thomas Chen

Dona L Archer

H Vince Brown

Ronald Wayne Underwood

Connie Carol Brown

Vince H Brown

Teresa Anderson Rhodes

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.

Preparation and use of high brightness kaolin pigments

Paper coating composition comprising an engineered kaolin pigment containing stacks and platelets of unground coarse particles where greater than 96% by weight is less than 5 microns, of which some kaolinite books or stacks are concentrated in the greater than 1 micron size fraction; 88% to 95% by weight is less than 2 microns; 65% to 85% by weight is less than 1 micron; and 15% to 25% by weight is less than 0.25 micron. A first embodiment comprises particles with a shape factor Ad between 7 and 9 which represents a significant number of stacks and some platelets. A second embodiment comprises particles with a shape factor of 11 or 12 which represents the presence of some stacks with a majority of platelets. The kaolin clay pigments form clay-water slurries of 69% solids or greater. As a coating, the composition gives a G. E. brightness between 88 and 94. The engineered pigment is processed so that the desired shape factor is met, which shape factor is equated to the aspect ratio or morphology of the pigment.

Engineered kaolin pigment composition for paper coating

A kaolin clay pigment comprises a coarse kaolin clay or a blend of a coarse kaolin clay with a fine kaolin clay. The coarse kaolin clay is a delaminated and defined pigment product with an overall shape factor greater than about 12. If the coarse kaolin clay is fluid at about 65% to about 75% solids, then it is used by itself as the kaolin pigment. If it is not fluid, it is blended with a fine kaolin clay in amounts ranging from about 0.1% to about 30.0% by weight of the blend. The coarse kaolin clay fraction has a Hinckley Crystallinity Index greater than about 0.6 and the fine kaolin clay has a Hinckley Crystallinity Index less than about 0.5. The pigment has a G.E. brightness of about 90.5 and a particle size distribution such that at least about 90% by weight of the particles has an e.s.d. less than about 2 &mgr;m and about 30% by weight of the particles has an e.s.d. less than about 0.25 microns. At about 65% to about 75% solids, the Hercules viscosity is greater than 250 rpm at about 18 dynes and when used in a coating formulation, exhibits improved sheet brightness, sheet gloss, sheet opacity and print gloss.

Kaolin clay pigment for paper coating and method for producing same

Dispersing agents and their use

Paper coating composition comprising an engineered kaolin pigment containing stacks and platelets of unground coarse particles where greater than 96% by weight is less than 5 microns, of which some kaolinite books or stacks are concentrated in the greater than 1 micron size fraction; 88% to 95% by weight is less than 2 microns; 65% to 85% by weight is less than 1 micron; and 15% to 25% by weight is less than 0.25 micron. A first embodiment comprises particles with a shape factor between 7 and 9 which represents a significant number of stacks and some platelets. A second embodiment comprises particles with a shape factor of 11 or 12 which represents the presence of some stacks with a majority of platelets. The kaolin clay pigments form clay-water slurries of 69% solids or greater. As a coating, the composition gives a G.E. brightness between 88 and 94. The engineered pigment is processed so that the desired shape factor is met, which shape factor is equated to the aspect ratio or morphology of the pigment.

A method of enhancing the brightness and increasing the yield of a kaolin clay by optimizing the removal of the titania and mica impurities in the clay and the amount of clay remaining in the slurry is disclosed. The method is a selective flocculation process wherein the clay is blunged, dispersed, and conditioned before flocculation. In the flocculation step, a high molecular weight anionic polymer and a low molecular weight anionic polymer, such as sodium polyacrylate, are added to the slurry after the conditioning process, whereby the titania-mica enriched flocs are separated from the suspension which is enriched with kaolin. This final kaolin product has titania levels ranging from 0.1% to 0.5%, a reduced mica level, a high usable product yield, and a brightness greater than 89.5 and at least 91.5.

Method for separating mixture of finely divided minerals and product

An improvement is disclosed applicable to the method for producing a calcined kaolin by the steps of wet beneficiating a crude kaolin to form a slurry of the beneficiated kaolin; dewatering the slurry to form a substantially dry calciner feed; and calcining the feed at a temperature of at least 1450.degree. F. by passing a stream of hot gases through a calciner in which the kaolin feed is resident, whereby an exhaust stream of hot gases is generated which entrains quantities of partially calcined and hydrous kaolin pigment fines. The improvement, enabling useful application of the kaolin pigment fines, comprises recovering the kaolin pigment fines from the exhaust stream for use in papermaking. The fines can be recovered at a wet scrubber, and after being partially dewatered, shipped directly as a product slurry to the paper maker.

Method for producing high opacifying kaolin pigment

Growing community of inventors

Sandersville, GA, United States of America

William L Garforth