微囊化溶剂对吡唑醚菌酯微囊悬浮剂应用性能的影响

利用安全溶剂替代农药制剂中的有毒溶剂符合农业可持续发展的要求,乳油中有害溶剂替代已经颇具成效,而微囊剂型中的溶剂替代也应该引起重视。本文先通过比较油酸甲酯和150# 溶剂油对油相稳定性的影响以确定溶剂的种类和用量,采用界面聚合法分别以油酸甲酯和150#溶剂油为溶剂制备了9%吡唑醚菌酯微囊悬浮剂,之后考察了两种制剂的释放性能、抗光解性能和田间应用效果。结果表明;以油酸甲酯为溶剂,当原药与溶剂质量比为1 : 2时,所得的吡唑醚菌酯微囊为球形,平均粒径为2.92 μm,与以150# 溶剂油为溶剂制备的微囊相比,在快速释放液中,20 min时前者中吡唑醚菌酯的累积释放率为92%,后者仅为50%。在模拟紫外光强度下,在100 min时,以油酸甲酯作溶剂的微囊中吡唑醚菌酯含量比以150#作溶剂的微囊中吡唑醚菌酯的含量高30.59%。田间药效试验结果表明,在施药后32 d,用以油酸甲酯为溶剂制备的9%吡唑醚菌酯微囊悬浮剂处理比以150# 溶剂油为溶剂的微囊悬浮剂处理和250 g/L吡唑醚菌酯乳油处理对花生叶斑病的防效分别高16.59%和29.34%。表明溶剂对农药微囊制剂的稳定性和应用性能均存在影响,应该优化筛选。本研究可为农药微囊制剂的精细化加工提供理论依据。

Effects of microencapsulated solvents on the application features of pyraclostrobin microcapsule suspension

It is in line with the requirements of agricultural sustainable development to find safe solvents to replace toxic solvents in pesticide formulations. The substitution of harmful solvents in EC has been quite effective, and the substitution of harmful solvents in the microencapsulated formulation should have been given much attention. The effects of methyl oleate and 150# solvent oil on the stability of the oil phase were evaluated to select the type and amount of solvent, then the release performance, anti-photodegradation performance and field application effect of 9% pyraclostrobin microcapsule suspension were investigated in this work. The results showed that when methyl oleate was used as a solvent and the mass ratio of technical material to solvent was 1 : 2, the microcapsules were spherical with an average particle size of 2.92 μm. Compared with the microcapsules with 150# solvent oil as solvent, the cumulative release rate of microcapsules with methyl oleate as solvent was 92% at 20 min, while that of microcapsules with 150# solvent oil was only 50%. Under the simulated UV light intensity, the content of pyraclostrobin in the microcapsule with methyl oleate as solvent was 30.59% higher than that in the microcapsule with 150# solvent oil as solvent at 100 min. The results of the field efficacy test showed that the control efficacy of 9% pyraclostrobin microcapsule suspension with methyl oleate as solvent was 16.59% and 29.34% on 32nd day after application, respectively, which were higher than that of 9% pyraclostrobin microcapsule suspension and pyraclostrobin EC with 150# solvent oil as solvent. The above results suggested that the solvent has an effect on the stability and application performance of pesticide microcapsules, and the formula should be further optimized, which provides a theoretical basis for the fine processing of pesticide microcapsules.