Consolidation of particulate suspension - model study with plastic pigments

A4 Conference proceedings

Internal Authors/Editors

Publication Details

List of Authors: Martti Toivakka, Pekka Salminen, Yohannes Chonde, Douglas Bousfield
Publisher: TAPPI press
Place: Atlanta
Publication year: 1997
Publisher: TAPPI Press
Book title: 1997 TAPPI Advanced Coating Fundamentals Symposium
Journal acronym: P TECH AS P
Start page: 89
End page: 101
Number of pages: 13
ISBN: 9780898526899
ISSN: 1047-3033


The microscopic mechanisms and parameters controlling consolidation and leveling of particulate suspension coatings on paper were studied. A simplified model system consisting of a model suspension of plastic pigment and impermeable substrates with well defined topog. was used. The suspension contains spherical carboxylated polystyrene plastic pigment in water and the substrates were a photocopier transparency and an ink jet printer transparency. A math. model based on a dynamic simulation technique was used to clarify the mechanisms influencing leveling of suspensions. High initial solids content resulted in smooth surfaces, high opacity, and high light scattering efficiency of the coated samples. The compression of electrostatic potential through addn. of electrolyte resulted in high packing d. of the coating layer. The leveling movement of the particulate suspension was limited by build-​up of a dense layer of particles at the coating-​air interface, and by flocculation of the suspension. The difference in immobilization and initial solids content controlled the final surface roughness of the coatings.

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