Submitted to: Fine Particle Society
Publication Type: Abstract Only
Publication Acceptance Date: 4/3/1998
Publication Date: N/A
Technical Abstract: Dispersion of pigment is one of the important factors determining the performance of a coating. Although its importance relative to others such as composition, a poorly dispersed coating will invariably be inferior in performance to a properly dispersed one of similar composition. Successful dispersion is as important to the optical and protective properties of a coating as the correct selection and proportions of the constituent raw materials. Most pigments used in commercial printing inks have ultimate average particle sizes in the range of 30 millimicrons to 200 millimicrons which places them in the "colloidal" range. Dry colors, however, frequently consist of clusters of particles called aggregates, which is a principal objective of any dispersion process. Another objective is to cause the vehicle to displace the air envelope surrounding the particles, that is, to wet the pigment. In order to evaluate the efficiency of a dispersion method, the extent to which the pigment clusters have been broken and wetted must be measured.