Preparation And Stability Of Hexaflumuron Suspension Concentrate

With the increasing awareness to protect the environment, we have focused on the environment friendly and low-cost water-based formulation instead of the Emulsifying Concentrate with organic solvents. Suspension Concentrate (SC) has become one of the development directions of new pesticide formulation which is efficient and safe, and has good environmental compatibility et al. Now the method of preparation of SC mostly was mechanical grinding. In this paper, the preparation of Hexaflumuron SC was researched by solvent replacement from condensation. On the basic of the selection of suitable solvent and the wetting and dispersing agents, the influence of the active ingredient content on preparation was systematically studied. Zeta potential of the system which was influenced by the electrolyte was also studied. We hoped that it could provide a theoretical basis for the development of SC. This paper mainly studied from the following aspects:1. We screened the solvent and the wetting and dispersing agents of 1% Hexaflumuron SC which produced by a solvent displacement technique by means of measuring average size and Zeta potential analysis. Determining acetone as its solvent, the mass ratio of acetone and the active ingredients was 10:1. Wetting and dispersing agents was: MOTAS and 700 #, and the mass ratio of MOTAS and 700# was 1:1. When the mass fraction of MOTAS was 1.25%, the stability of Hexaflumuron SC was best. The dispersion stability of Hexaflumuron SC could be largely enhanced when the ethanol was added. The dispersion stability attained best near 31.2% of the mass fraction of ethanol.2. The content of the active ingredient of Hexaflumuron SC influenced the formation of emulsion droplet. With the content of active ingredient increasing, the average particle size increased, the absolute value of Zeta potential of particles first increased and then decreased, and dispersion stability reduced. On the basic of select suitable solvents, wetting and dispersing agents, we carried out a single factor experiment. We studied the influence of the stirring speed, stirring time, dropping rate and temperature on the average size of particles of Hexaflumuron SC. The results showed that all above factors affected the average size of the particles and then determined the stirring speed: 300r/min, stirring time: 30min, dropping rate: 1ml/min, temperature: room temperature. On the basic of previous experiments, we found that the concentration of organic solvent which effected average size of hexaflumuron SC particles had the largest influence, far greater than other factors. By increasing the concentration of organic solvent could significantly reduce the average size of Hexaflumuron SC particles. The concentration of active ingredient increased from 1% to 6%, effectively saving the cost of production.3. Take 1% hexaflumuron water suspension as the research object, this paper studied the influence of the electrolyte on Zeta potential. The results showed that Zeta potential of hexaflumuron SC were negative within the experimental pH values. pH affected the dissociation of dispersant in water. With the increaseing of pH, the absolute value of Zeta potential first increased and then decreased. When the pH was about 8.39, the absolute value of Zeta potential is maximum. The type and concentration of salt ions affected the Zeta potential of hexaflumuron SC. With the increasing of the concentration of MgCl2 and NaCl, the absolute value of Zeta potential decreased, and the impact of MgCl2 on the system was even more significant.