Dispersing of Coating Clay - How Unit Design Parameters of Disperser Influence It, 1993 Coating Conference Proceedings

The main component in a normal coating color is the pigment or pigments calculated by weight. The pigments must be carefully dispersed in order to achieve the best possible coating quality. Poor dispersing leads to such problems as blade scratches, excess rejects at screens, rheological fluctuations and runnability disturbances at coaters. In this study we investigated the influence of different design parameters of the disperser on the whole process called pigment make-down and on the quality of dispersed china clay. For examining the effects of different variables a laboratory disperser with necessary data logging equipment was used. The purpose of the study was to find an optimized way to control the make-down process in the disperser.

The dispersing energy was measured with a torque sensor installed on the shaft of this laboratory disperser. The speed of the rotor was adjustable and the temperature of the dispersion was recorded. All this data was registered by data loggers. The different sequences of the make-down process were observed with these instruments and by visual follow-up of the dispersing process.