The importance of particle dispersions in paint formulations and the need for better characterization methods - poster
Dr David Elliott
AkzoNobel Decorative Paints, Slough, UK

Paints comprise dispersed particles of several kinds having wide ranges of particle size from tens of nanometres to hundreds of microns and a variety of shapes and aspect ratios. These include polymer latex particles and Titanium Dioxide white pigment at the smaller (colloidal) size end of the range, with near spherical shapes and mineral extender particles with largest particles of more than 100 microns and with diverse shapes from blocks to fibres and plates. Much R&D effort in the paint industry is spent on formulating to achieve stability of these complex dispersions, so that long product shelf-lives can be offered and so colours can be made accurately and reproducibly.

Formulating work and problem solving usually takes the form of extensive designed experimentation and time-consuming stability testing. Attempts to gain deeper understanding and use more fundamental scientific approaches are hindered by the limitations of current characterisation methods, when it comes to complex, multi-modal, concentrated dispersions like paints, which typically have particle volume concentrations in the range of 20 to 50%.