• thickener
• viscosity
• formulation
• thixotropy
• flow curve
• 2 intervals thixotropy test
• paints
• waterborne
• rheology

This thesis work was carried out at the research and development center of AkzoNobel Decorative Coatings bv in Sassenheim, The Netherlands.
The main aim was understanding how to tune the rheology of waterborne paints in order to control their thixotropy and formulate a non-drip paint with good brush load and good levelling as well.
The samples were tested via brush application and via rheological tests (such as flow curves and thixotropy tests), which were optimized, increasing their repeatability and reproducibility.
By comparison of commercial products, the target paint was defined in terms of rheological values (viscosity with respect to the shear rate, shearing time and relaxation time).
A screening was carried out on the main classes of rheology modifiers, namely chelates, clays, hydrophobically modified urethanes (HEUR) and cellulose derivatives. Each rheology modifier was tested in combination with binders having different chemistry (acrylic binders, alkyd binders and their polyurethane-modified version).
The outcomes included a wide portfolio of rheology modifiers for different purposes and a guideline for future formulations.