Impact of Potassium Carbonate on the Detergency Behavior of Nonionic Surfactants

Potassium carbonate is examined as an alternative electrolyte to evaluate its impact on the optimal HLD range for detergency and interfacial tension (IFT) values with nonionic surfactants. The reason for using K 2 CO 3 is that the HLD range for nonionic surfactants is more than a factor of two larger versus NaCl. Using HLD parameters determined from test‐tube experiments using hexane, a pronounced shift in the optimal cleaning range with tripalmitin as the soil was observed when K 2 CO 3 was used. For two narrow range ethoxylates, the optimal HLD range shifted to approximately HLD = −1 to HLD = 3, while for a broad range ethoxylate the optimal range shifted further to approximately HLD = 1 to HLD = 5. IFT measurements with hexane as the oil for NaCl and KCl salts had a minimum at HLD≈1 while for K 2 CO 3 and Na 2 CO 3 no minimum was observed. These results indicate that potassium carbonate drives the formulation toward a more lipophilic character before peak detergency is achieved, thereby significantly altering the HLD conditions required for optimal cleaning. The disagreement in HLD between IFT and test‐tube experiments is a consequence of partitioning of more hydrophobic components of alcohol ethoxylates to the oil phase.