Application Of Polycarboxylate And Sulfonate Surfactant In Pesticide Preparations

The dispersant is a surfactant which can maintain the particle stable in the suspension. Terpolymers polycarboxylate dispersants and P-naphthalene sulfonate dispersants are two kinds of anionic dispersant. In this paper, we have study the effect of the two kinds of dispersants compound and the application in water dispersible granule and suspension concentrate.At first, this paper mixed foreign polycarboxylate dispersants（2700）、 β-naphthalene sulfonate dispersants（2425） and domestic polycarboxylate dispersants（SD-819）、β-naphthalene sulfonate dispersants（SD-661） respectively according to the different proportion of mass. And than we measured the surface tension for the single one and the associative compound.We also analyzed the change of surface performance and the interaction between polycarboxylate dispersants and β-naphthalene sulfonate dispersants through correlated calculation.The results:when the mixed ratio of 2700 and 2425 is 7:3,the surfactant mixed system has the lowest surface tension for 46.2mN/m; when the mixed ratio of SD-819 and SD-661 is 2:8,the surfactant mixed system has the lowest surface tension for 51.7mN/m; the surfactant mixed system of 2700 and 2425 has |β^m|>|ln （CMC₁/CMC₂）|=0.571, the surfactant mixed system of SD-819 and SD-661 has |β^m|>|ln（CMC₁/OC₂）|=0.314,the two data indicates two kinds of surfactants is synergies effect; the mixed effect of SD-819 and SD-661 is better than the 2700 and 2425,and has a lower CMC for 2.3g/1 and better pm for-8.75.We have use these mixed surfactants to prepare 80% Ametryn WDG and compare the effects of different mixed ratio. By measuring the two samples for suspension rate of before and after the thermal storage, wettability, collapse resistance, resistance to hard water, and the change of performance such as foamability, we analyze the best application proportion of dispersant and dispersant distribution rule.The results:when the mixed ratio of SD-819 and SD-661 is 2:8 and 3:7,the performance of 80% Ametryn WDG is good and meet the requirement of pesticide formulation.Effect of mixed dispersant application in 20% Dinotefuran SC was studied, in order to improve the water separating performances and crystallization performances after the thermal storage. By measuring the two samples for suspension rate of before and after the thermal storage, viscosity, crystallization rate, zeta potential and particle size distribution and the wet-screened pass rate,we found that:when the mixed ratio of SD-819 and SD-661 is 1:1, the suspension rate is 96%, the water separating rate is 7-12% and the crystallization rate is 0%.We found that the particles of 20% Dinotefuran SC did not grow up and kept stability after thermal storage observed through the optical microscope and scanning electron microscope.