Packing in the wet state of a suspension of pigment particles at fixed volume concentration is affected by a threshold addition of latex binder provided the particle size of the admixed particles is sufficiently similar to the pores created. The resulting consolidated dry structure displays shrinkage resistance resulting from the spacing effect of high T_g latex. This study investigates a range of pigment and latex volume concentrations providing a means of extrapolating the combined independent concentrations. Increasing pigment content leads to increased sensitivity to latex volume concentration. The progression toward consolidation follows an exponential viscous (disruptive) response to the presence of latex spheres and supports observed resistance to capillarity-induced shrinkage by the correct choice of latex particle size and hardness in relation to pigment packing void size. Using mercury porosimetry, it is shown that the critical disruption point for latex addition in the wet state leads to a complete closure of the pore structure in the dried state. These findings have been correlated with a discontinuity in breaking elongation of a coated substrate as a function of latex amount. Critical pigment volume concentration can, therefore, be pre-determined in the wet state by extrapolation of low shear rheological data given that the particles involved tend to create pores which are of a similar size to the latex particles, such that the latex can act to disrupt the packing as volume fraction increases. Hence, the degree of shrinkage resistance can be formulation controlled and the degree of coating strength determined.
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