Consolidation of Particulate Suspension -- Model Study with Plastic Pigments, 1997 Advanced Coating Fundamentals Symposium Proceedings

The microscopic mechanisms and parameters controlling the consolidation and leveling of particulate suspension were in-vestigated. A simplified model system consisting of a model suspension of plastic pigment and impermeable substrates with well defined topographies was used. A mathematical model based on a dynamic simulation technique was used to clarify the mechanisms influencing the leveling of suspension.

A high initial solids content resulted in smooth surfaces, high opacities and high lightscattering efficiencies of the coated samples. The compression of electrostatic potential through addition of electrolyte resulted in a high packing den-sity of the coating layer. The leveling movement of the partic-ulate suspension was limited by a build-up of a dense layer of particles at coating-air interface, as well as flocculated state of the suspension. The difference in immobilization and initial solids content was found to control the final surface roughness of the coatings.