SEDL / STP / STP1146-EB / STP20188S

Using Nonionic Surfactants in Aqueous Formulations

Utz, CG
Group Leader, BASF Corporation, Wyandotte, MI

Drewno, GW
Technical Specialist, BASF Corporation, Wyandotte, MI

Hollis, RP
Market Development Specialist, BASF Corporation, Parsippany, NJ

Pages: 12    Published: Jan 1993

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Abstract

Water-based formulations for liquid actives are relatively new to the agricultural market. Surfactant combinations have been identified which provide long-term stability and good dilution characteristics in concentrated emulsions (oil-in-water emulsions [EW]) and suspoemulsions (combinations of a liquid and solid active in a water-based formulation). For EW formulations, surfactant combinations consist of two nonionic EO/PO block copolymers. One has relatively hydrophobic character containing little EO and acts as emulsifier, while a relatively hydrophilic component with a large EO content facilitates dispersion in water. Suspoemulsions are stabilized by adding block copolymers containing 30 to 50% EO to commercial flowables. Some formulations require additional polyacrylate polymer as dispersant. These stable formulations are made without any thickeners or other stabilizers.

EW formulations have been demonstrated with pyrethroids and 2,4-dichlorophenoxyacetic acid. Combinations of malathion/carbaryl and metolachlor/atrazine have been successfully formulated in suspoemulsions. The physical stability and dilution characteristics of the formulations are described.