Modelling Coating Structure Development: Monte-Carlo Deposition of Particles with Irregular Shapes, 2003 Advanced Coating Fundamentals Symposium Proceedings
There is an increasing interest in enhancing coated paper performance by combining the unique properties of various pigments, i.e. developing multi-pigment coating formulations. An understanding of the synergy between pigments of different sizes and shapes is therefore becoming critical. The literature on this subject
is rather empirical and fragmentary. In this report, we introduce an improved 3D Monte-Carlo deposition model to simulate coating structure development for irregularly shaped particles. The model relies on the minimization of the total energy of the particle system, which is defined as a sum of three terms: a pair interaction that accounts for collisional interactions, a gravitational potential energy, and a drag potential energy that takes into account the drainage rate of the colour. The model predicts that pigments with higher aspect ratios give a more porous structure and a smoother surface when applied at high solids content. Coating at low solids content (<45-55%) is="" shown="" to="" produce="" “looser”="" and="" more="" disordered="" structures,="" especially="" in="" the="" case="" of="" platelet="" pigments="" like="" clay.="" these="" results="" agree="" with="" practical="" and="" experimental="" observations.="" when="" blending="" clays="" with="" calcium="" carbonates,="" the="" model="" predicts="" the="" occurrence="" of="" maximum="" pore="" volume="" and="" surface="" micro-roughness="" at="" specific="" mixing="" ratios.="" the="" location="" of="" these="" maxima="" varies="" significantly="" with="" the="" particle’s="" aspect="" ratio,="" the="" relative="" size="" of="" the="" blended="" pigments,="" and="" the="" solids="" content="" of="" the="" suspension.="" with="" further="" experimental="" validation,="" this="" model="" has="" the="" potential="" of="" being="" used="" as="" a="" tool="" for="" designing="" and="" optimizing="" coating="">