Volume 7, Issue 9 (October 2010)
Application of New Solid Polymeric Dispersant, Easy-Sperse® P-20 (Spray-Dried Polymer Composites) in Suspension Concentrates and Water Dispersible Granule Formulations—Improvement in Suspensibility and Rain-fastnesss
Easy-Sperse® P-20 [ES P-20] is a synergistic, spray-dried composite of polyvinyl pyrrolidone (PVP) and partially neutralized methyl vinyl ether maleic acid butyl/ethyl half ester polymer. In this work, ES P-20 was used as an additive in water-based suspension concentrate (SC) and water dispersible granule (WDG) for improving the suspensibility and rain-fastness performance of those samples. SC samples with 40 % Diuron, 30 % Isoproturon, and 40 % Imidacloprid were prepared. The suspensibility, rain-fastness, viscosity, pH, heat-aged stability, and particle size distribution were measured and compared. Our data showed that the use of ES P-20 could improve the SC suspensibility. The majority of the samples tested reached >70 % suspensibility at 0.2 %, 0.5 %, and 1 % active ingredients after dilution with water and after 4 h standing at room temperature. For some samples, the suspensibility was found to be >90 %, while the formulations without ES P-20 showed a suspensibility of <50 % in most cases. After adding ES P-20, the SC sample with 40 % Diuron also demonstrated better rain-fastness. This indicates that ES P-20 can enhance water resistance during water rinsing. WDG samples with 90 % Atrazine, 80 % Diuron, and 75 % Nicosulfuron were also made successfully using ES P-20 as one of the polymeric dispersants via a laboratory basket extruder. Performance data including friability/hardness, disintegration, wetting time, and suspensibility were evaluated. The data provided illustrate the advantage of using ES P-20 for improving the suspensibility in water. In conclusion, ES P-20 shows synergy with anionic dispersants in dispersing AIs. It also improves heat-aged stability and reduces settling of the AI with time. The formulations with ES P-20 showed increased resistance to water wash in our laboratory tests. The results demonstrated that ES P-20 can be used effectively in formulating zero volatile organic compound compositions like SC and WDG.