The Waterborne Symposium 2025

Co-Authors: Christin Jäger and Katja von Nessen

Abstract
"In the coating industry there is increasing demand for environmentally friendly and safe products driven by regulations such as reduction of VOCs and CO2 emissions and the replacement of critical raw materials. Bio-based raw materials have been found to be appropriate substitutes as they frequently exhibit a significantly lower carbon footprint, a better toxicological profile as well as the capability of biodegradation.

In this study, the performance of bio-based citrate esters as coalescing agents for an architectural paint formulation was investigated and the results were compared to market standards. Furthermore, the useability of xanthan gum as rheology modifier was studied and the performance was compared to cellulose thickeners (HEC, Hydroxylethycellulose) for the same application. Contrary to most of the classical coalescent agents, citrate esters are non-VOC and comply with the latest toxicological and environmental safety requirements: they are characterized by highly efficient solvation, low migration and non-VOC attributes. To showcase those features 2.4 wt% coalescent agent were incorporated into an architectural paint based on an acrylic binder. The deviations in properties of the dried paint were not significant among the tested coalescent agents. The study also revealed that the same dosage of xanthan gum leads to a low shear viscosity about 60% higher compared to cellulose thickeners. This effectively improves storage stability, due to the high stabilization of pigment particles, while leading to comparable levelling and sagging. High shear viscosity on the other hand is about 50% lower, which improves applicability. The versatility of xanthan gum is not limited to pigmented systems. It is possible to adjust the viscosity of clear coats, while maintaining transparency."