| 摘要 |
<p>PURPOSE:To obtain efficiently a pigment dispersion which is uniform and has a low water content, by feeding a hydrophobic liquid org. medium and a water- wetted cake contg. a pigment to a specified screw extruder to carry out a phase inversion stage and a dehydrating stage. CONSTITUTION:Given amounts of a hydrophobic liquid org. medium and a water- wetted cake contg. a pigment are fed to a screw extruder with double screws rotating in the same sense to continuously carry out a phase inversion stage, a dehydrating stage and, if necessary, an after-treatment stage within the same extruder. The optimum mixing ratio of the org. medium to the pigment is defined by the property of the org. medium, but it is necessary to be a mixture composed of an org. medium and an aq. medium in a ratio of 0.25-1.5pts.vol. of the aq. medium to 1pt.vol. of the org. medium. In the practice of the above method, it is advantageous to use a water-wetted cake contg. a pigment, which has a pigment content of 40% or above.</p> |
