Mineral thickeners (attapulgites, smectites) form a gel with water after the water penetrates the lamellar layers. The created colloidal form turns out to be effective to varying degrees as a thickener in latex paints. The slide below shows that in some cases of mineral thickeners, the obtained rheological properties may depend on the water with which the paints were prepared and the previously hydrated mineral thickeners.
To some extent, there may be a relationship between the obtained rheological properties (e.g. shear thinning index, thixotropy index) and the stability of paint viscosity over time. The above slide shows an example of the behavior of paints prepared with three different mineral thickeners, each of which was prepared entirely with demineralized water (DI water with conductivity < 1 µS/cm) and tap water (water hardness 30 °f)
The phenomena of the influence of variable hydration depending on the purity of water (the presence of ions, water hardness, the degree of demineralization) can be observed when transferring the formulation between the laboratory and the paint dyeing plant, are located in a different location, or between factories where the same paint is to be produced, based on on the same ingredients. Then it may turn out that the influence of water quality makes it necessary to reformulate the proportion of mineral thickeners.
Some mineral thickeners do not show any dependence on the type of water, however, it should be remembered that the problem with obtaining the appropriate viscosity may not be related to the ineffective mineral thickener.