RHEOLOGY OF COATING COLORS AND THEIR RUNNABILITY ON A CYLINDRICAL LABORATORY COATER

We present results of our ongoing study on the rheology of coating col ors. For this study, we chose simple coating colors made up of kaolin acid latex and report results on the transient viscosity at low shear rate and small-amplitude oscillatory data obtained using a controlled- strain rheometer. The rheological properties are compared with runnabi lity results on a Cylindrical Laboratory Coater. We report a surprisin gly good correlation between low-deformation transient rheological mea surements and runnability. Although very large deformation rates (appr oximate to 10(6) s(-1)) are encountered in the coating process, the co ntact time for the flow under the blade is extremely small (approximat e to 10(-5) s). Thus, low-deformation rheological characterization is believed to be significant in relation to coating.