Optimized rheological properties of silicon-based paints. An investigation of thickeners.

Abstract

Sioo Wood Protection AB produces silicon-based paints for exterior wood. Two of the products that the company produces are SiOO:X Panel Colour Wood Protection and SiOO:X Panel Colour Surface Protection which are used together to create a coating on wood. These products increase the lifespan of the wood it is applied on and gives the wood a silver-grey color. SiOO:X Panel Colour Wood Protection and SiOO:X Panel Colour Surface Protection suffer undesired sedimentation during storage and application as a result of low viscosity. The viscosity can be modified by using different thickeners. In this project, several thickeners were evaluated in SiOO:X Panel Colour Wood Protection and SiOO:X Panel Colour Surface Protection to see which thickeners increased the storage stability without impairing the other properties of the paints. The thickeners were evaluated by producing paint samples containing the thickeners and measuring the samples storage stability, color, viscosity, gloss, non-volatile matter, sag resistance, leveling and water repellency. The samples were also evaluated by performing natural weathering tests, leneta paper applicator tests, and tests of how easily the paints could be applied by brush. Most thickeners did not increase the viscosity more than the currently used thickener. However, thickeners based on diutan gums and xanthan gums could be used to improve the rheological properties of samples of SiOO:X Panel Colour Wood Protection without impairing the functionality of the samples. Combinations of thickeners based on one type of clay and xanthan gums or diutan gums also added good storage stability, improved application by brush, and made the SiOO:X Panel Colour Wood Protection samples protect wood well. One of the evaluated hydroxyethyl cellulose thickeners may be used in SiOO:X Panel Colour Surface Protection but at a lower amount than 0.9 wt% as that gave the sample good storage stability but too high viscosity for application.