A class of nonionic surfactants has been observed to function as associative thickeners, dispersants, and wetting agents in aqueous flowable pesticide formulations at use levels of 1 to 3%. This phenomenon provides an alternative to conventional thickeners such as gums and minerals. These surfactant/thickeners require a finely ground substrate, such as a pesticide active ingredient for rheology modification. Combinations of these surfactants with other nonionic and anionic surfactants permit the formulator to control the rheology or suspensibility, or both, in a wide range of water hardnesses.

This phenomenon has been demonstrated with several pesticide active ingredients including atrazine, linuron, chloroneb, and carbaryl. The viscosity, viscous yield, suspensibility foaming behavior, and product stability of several prototype atrazine formulations are described.