Application Of Wetting-dispersant EH In Pesticide Formulations

The increasing of particle size of active compound in pesticide formulations duringstorage period is called the granular grown phenomena. This phenomenon is commonlycollected, with the effects of ostwald ripening and particle concentrations. It is seriouslyoccurred in SC of high concentration, resulted in delamination and agglomeration in ashort period, and even caused the useless of formulations, which significantly limits thedevelopment of formulations. The thermodynamic stability of pesticides formulationsaffected by the additive of wetting-dispersant, study of the function principle of wetting-dispersant in SC is important for wetting-dispersant additive and solution development andselection of the thermodynamic stability of the SC. The main findings were as follows:1. The10%Beta-cypermethrin SC was developed with the wetting-dispersant EH andmethod of wet milling and the indicators of it were determined. Finally the effects ofwetting-dispersant EH and traditional wetting-dispersant on the formulation after storedunder thawing conditions and after milled different time were researched. The feasibilityand rationality of the wetting-dispersant EH were validated by vertification of the sameformulation with the same content using the common registered pesticide products. Theresults indicated that along with the increase of the dosage of wetting-dispersant EH, thesuspension average diameter decreased, the diameter distribution was relativelyconcentrated, Zeta potential increased, but when the dosage of wetting-dispersant EHreached a certain value, that the trend was smooth. When the dosage of wetting-dispersantEH was1.5%, the system average particle size reached the minimum1.48μm, the Zetapotential reached the maximum43.35mv, even there was almost no change after the hotstorage, which well controlled the growing up of diameter, and improved the stability ofpreparation.2. The application of EH and the influences of emulsifiers in50%chlorpyrifos EW onaverage diameter, diameter distribution and phsical stability were researched. Theadaptability of different formual with processing equipment and water quality was studied.High stable emulsions could prepared with EH, pesticide emulsifier605#and pesticideemulsifier NYLO3complex1:3:1as emulsions and the mass fraction of the mixture was6%, using high speed shearing machine with continuous cutting at the rate of3000r/min in3min. The average diameter was about0.45μm, diameter distribution was0.27-0.89μm. The50%chlorpyrifos EW prepared with EH, pesticide emulsifier605#and pesticideemulsifier NYLO3had a better stability than the conventional emulsions.3. In order to improve the stability of40%acetochlor· atrazine suspension emulsionand provide a basis for practical production, the wetting-dispersant of40%acetochlor·atrazine suspension emulsion was selected on the basis of average diameter andZeta potential. The effect of the variety and amount of wetting-dispersant, milling time onthe stability of formulation and the stability at low and high temperature of the formulationwere determined.According to the results,optimum combination were as follows:wetting-dispersant m(EH):m(NNO)=1:4and mass fraction of the mixture was1.5%,milling time1.5hours. Under these conditions, the average diameter of the product was1-2μm, suspensibility was over90%, with good flowability and stability.