SIMULTANEOUS-OPTIMIZATION OF TIO2 OPTICAL-PERFORMANCE AND BINDER DEMAND IN COATED BOARD FORMULATIONS USING KNOWLEDGE FROM THE PAINT CHEMIST

TiO2 extension in coated paper has long been a goal of papermakers and suppliers. Most current technology has been based on replacing TiO2 w ith pigment that mimics scattering efficiency of TiO2. In coatings whe re 10% of the pigment blend is TiO2, this is the best approach. In coa tings where the level of TiO2 is 25%-50% of the coating, the introduct ion of a pigment to enhance TiO2 performance allows significant reduct ion in the level of TiO2 without changing the total binder demand of t he coating. This paper presents theory and data to show that strategie s used in paint technology are helpful in coatings that contain high a mounts of TiO2 and binder such as board coating. Laboratory studies an d pilot coater work demonstrate the efficacy of this approach. The res ults show that up to 50% of the titanium dioxide can be successfully r emoved from the coating without loss in optical or strength properties .