Nord Kaolin Company

Nord Naolin Company

Lester William House

Jerry L Curtis

Kenneth A Johnson

A pigment composition containing titanium dioxide (TiO.sub.2) and calcined clay in a weight ratio of between about 30:70 and 70:30, preferably between about 35:65 and 45:55 that is substantially free of a functional microgel component has advantages over a similar pigment containing a functional microgel. The pigment composition contains an amount of epichlorohydrin dimethylamine condensate that is sufficient to cationize the pigment, and lacks a microgel component. It is liquid when agitated. Preferably the composition has a solids content greater than about 55%, and most preferably between about 59% and about 61%.

Cationized pigments and their use in papermaking

This invention relates to structural aggregate pigment products that are cationic, and have improved wet-end retention. A method for converting anionic pigments to cationic pigments is also provided. More particularly, a structural aggregate pigment comprising a clay and/or titanium dioxide or other particulate components, and a functional microgel made from silicon and aluminum or zinc gel formers and a gelling agent such as calcium chloride, can be cationized by adding an effective amount of modified or unmodified epichlorhydrin dimethylamine condensate to a slurry of the structured pigment. The resulting cationic pigments have superior papermaking characteristics and a much improved retention.

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Macon, GA, United States of America

Lester William House