The manufacturing process parameters affecting color and brightness of TiO2 pigment

Background: Originally derived from colored minerals, inorganic pigment titanium dioxide is now highlyengineered particles that imparts color or functionality to the objects in which they are used. Optical properties such as color, opacity, brightness, and gloss are important to users of paper and board grades. The color and brightness of TiO2 sometimes get affected during its manufacture. These phenomena were observed in some commercial production plants. In order to investigate the effect of oil contamination on the pigment during its manufacturing process, such as from sand milling or larox filtration, the measurement on the brightness and color of titanium dioxide is made in this study. A correlation between the color and brightness values measured using different instruments is also included in this paper. Results: It is observed that whenever there is an oil contamination in the pigment, the vehicle b values measured in acrylic lacquer paint film of the pigment is affected. BYK L* is poorly correlated with the HunterLab vehicle L, and the dry Hunter b is in correlation with the DBC BYK b*, whereas L has no correlation with DBC BYK L. Conclusion: The contamination of pigment with lubricating oil from the machinery used for the manufacturing process influences both dry and vehicle b values. It is not possible to use HunterLab in place of BYK for the dry L and b measurements.