The Choice Of Wetting And Dispersing Agents In High-concentration Water Suspensions

With the continuous development of economy and living standards,people's awareness of environmental protection and safety is increasing,which also puts forward higher requirements for pesticide products.According to the registered pesticide dosage forms in 2018,water suspension agent has become a well deserved star product,because it is environmentally friendly,safe and efficient,and easy to spray.It can be seen that water suspension agent has a high market prospect High concentration water suspending agent is undoubtedly the research trend of water suspending agent products.However,as the water suspension belongs to the coarse dispersion system with unstable thermodynamics and kinetics,increasing the content of the raw material undoubtedly increases the difficulty of research and development,such as difficult grinding,particle aggregation,austenite ripening,water separation,bottom formation and other problems are more prominent.In order to solve this problem,the key is to select the appropriate wetting dispersant from the production practice and theoretical analysis.In this paper,thiazinone and tebuconazole are selected as raw materials.Two kinds of high concentration water suspensions,50% thiazinone water suspension and 430g/L tebuconazole water suspension,are developed.The selection of wetting and dispersing agents in the two kinds of high concentration water suspensions is discussed.The contents and results of this study are as follows:1.The wetting and dispersing agent with better effect on 50% thiazinone water suspension was screened out by flow point method;the combination was further optimized,and the wetting and dispersing agent was re screened by the results of heat storage;the optimal amount of wetting and dispersing agent was determined by viscosity and zeta potential;the appropriate thickener was screened by the heat storage and rheology of the preparation;and in this process,50% thiazinone water suspension was combined The physical and chemical properties of the floating agent,such as particle size change,suspension rate,viscosity,morphology,etc.after 14 days of thermal storage,as well as the surface performance data and synergistic parameters of the dispersant,can be used to assist judgment.At last,the optimal formulation of 50% thiazidone water suspension was selected: 50% technical,1.5% 850,1.5% 600,4% glycol,0.04% xanthan gum,0.5% magnesium aluminum silicate,proper amount of defoamer and replenishment of deionized water.2.Based on the previous work,polycarboxylate type dispersant 850 and polyoxyethylene ether type dispersant 601 p with good wetting and dispersing performance were used in 430 g / L tebuconazole water suspension.The results showed that the effect of the mixture of 850 and 601 p dispersant was better than that of the single use.Considering the rheological data,zeta potential and micelle kinetic diameter of the dispersant,the optimal compounding ratio of 430 g / L tebuconazole was m(850)/ M(601p)= 1.In addition,the dispersion mechanism of the mixture of polycarboxylate type dispersant 850 and polyoxyethylene ether type dispersant 601 p was discussed according to the experimental results.It was found that the mixture ratio of M(850)/ M(601p)was in the range of 0-1.With the increase of the dosage of 850,the stability of the system first decreased and then increased.