Preparation Of Metolachlor Microcapsule Suspensions And Property Characterization

Microcapsule suspension is a water-based pesticide formulation which developed rapidly and included many advantages such as good applicability for many active ingredients, relatively low cost and good market prospects. Compared with conventional pesticide formulations, micro-capsules not only can enhance effective utilization of pesticides with an extended persistence, but also reduce toxicity and pollution to the environment as well. Metolachlor microcapsule suspensions was prepared in this paper. The best conditions for preparation of microcapsule suspensions were optimized. The representative characterization methods were also established via corresponding apparatus. This paper refered and improved the selection and dosage of emulsifier, the selection of core wall ratios, catalyst acidification, cure time, the storage temperature, choosed the best technology of the preparation of the Acetamide microcapsule suspending agent.(1)Microcapsule suspension was prepared by in situ polymerization using urea formaldehyde as shell materials. The main performances of microcapsule suspension were investigated respectively.(2)The effect of formaldehyde to urea molar ratios, emulsifier, core wall ratios, catalysts,acidfing time, curing temperature, the p H value and suspension adjuvants on microcapsule suspension were researched. When the ratio of urea to formaldehyde was 1.75:1, the ratio of the core to the wall was 1.2:1, the quality of capsule suspension was the best, suspension rate ≥80%. 2% Tween 80 and 0.8% NNO were selected as emulsifier and suspension aid, which lead to ideal emulsifying effect. Hydrochloric acid was selected as a catalyst and the catalytic time was 120 min. When the p H=2, cured at 60℃for 90 min, to give desired particle size form and encapsulated microcapsules was more than 90%. Glycerin was selected as antifreeze.(3) According to the best conditions from experiments, the optimal preparation of microcapsules suspension were determined. The optimal preparation of microcapsules suspension were then validated and a complete and mature microcapsule suspensions of quality evaluation system was established.