STP1183: The Relation of the Pourability of Suspension Concentrates to their Viscoelasticity

    Dexter, RW
    Principal Research Scientist, U. S. Formulations Research, American Cyanamid Company, Princeton, NJ

    Szamosi, J
    Senior Research Chemist, U. S. Formulations Research, American Cyanamid Company, Princeton, NJ

    Pages: 12    Published: Jan 1993


    Abstract

    The pouring characteristics from 1 liter HDPE containers have been determined for a number of commercially available suspension concentrates and model solutions with controlled rheology. The pouring phenomenon was observed to occur in two phases: a rapid continuous stream over approximately the first 30 seconds, followed by a slower, dropwise drainage. The rheology of the fluids was measured using a Rheometrics RFS II variable strain rheometer in the dynamic mode. It was found that the weight of formulation remaining in the container after 1 minute's pour out correlated well with the viscous modulus of the fluid. The subsequent rate of drainage of the formulation from the container was dependent upon the elastic modulus of the formulation. Guidelines for development of formulations with efficient pour properties are given.

    The rinsing properties of several model fluids were examined. The rinsing efficiency was markedly dependent upon the amount of residue remaining after the initial pour and drain. It appears that the more elastic fluids do not wash off the container walls as effectively as the less elastic ones.

    Keywords:

    suspension concentrates, herbicides, pourability, drainage, rheology, viscosity, elasticity, rinsing, residues


    Paper ID: STP25126S

    Committee/Subcommittee: E35.22

    DOI: 10.1520/STP25126S


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