A Novel Rheology Modifier for Agrochemical Formulations

Abstract

Flowable formulations require a rheology modifier to prevent sedimentation phenomena. Rheology modifiers produce a “three-dimensional” gel network in the continuous phase resulting in a non-Newtonian fluid, which provides stability to the formulation. The rheology modifier must give high viscosity so the product does not separate during long-term storage but still allow the product to be easily poured from the package. The objective of this research was to evaluate a novel polymeric alkoxylate (PA) with carbendazin (500 g/l) for its effect as a rheology modifier on the formulation properties of viscosity, yield point, shear stress, shear thinning, stability, and spray droplet contact angle. PA has been formulated with other surfactants and solvents as a ready-to-use liquid rheology modifier. Formulations with four concentrations of PA formulated as a ready-to-use liquid [0.5, 1.0, 1.5, and 2.0 % weight per volume (w/v)], were evaluated and compared to formulations with four concentrations of a xantham gum (0.05, 0.1, 0.15, and 0.2 % w/v). Formulations with PA performed comparably to xantham gum for viscosity. PA provided desired behavior in shear stress and shear rate studies, and there was little variation in response because of changes in concentration. PA provided a higher yield point than xantham gum. Xantham gum provided stable formulations at all concentrations as measured by bleeding, settling, and particle size distribution. PA provided acceptable formulation stability at concentrations of 1.5 % (w/v) or greater. When diluted in water for field application, formulations containing PA had lower contact angles than xantham gum formulations which will result in improved wettability. PA is classified as a non-eye irritant.