高效氯氟氰菊酯微乳剂的制备及其液径尺寸

Preparation of Cyhalothrin Micro-emulsion Formulation and Its Micro-droplet Size

[目的]为了考察微乳剂和乳油剂型的液径(MDS)尺寸和稀释喷洒后的农药形态,使用复合乳化剂和乙酸丁酯溶剂,制备了质量分数为3.0%的高效氯氟氰菊酯微乳剂(ME)。经测试,各项性能达到国家标准。[方法]用激光光散射仪研究了不同水稀释倍数对3%高效氯氟氰菊酯微乳剂的MDS、多分散指数(PDI)和Zata电位值的影响,以2.5%高效氯氟氰菊酯乳油(EC)作为对比。[结果]研究发现MDS随不同稀释倍数稍微增大,且微乳剂的MDS小于乳油剂型。放置时间对其液径的影响显示2 h后微乳剂不同稀释倍数的液径均在100 nm以下。对2种剂型的30 mg/L稀释液,经喷施和干燥后进行扫描电镜观察。[结论]微乳剂形成棒状或块状结晶,晶体尺寸在几微米到十几微米范围;而2.5%高效氯氟氰菊酯乳油则形成树枝状结晶,晶体尺寸在50μm以上,这对药效发挥不利。

[Aims] In order to explore micro-droplet sizes （MDS） of micro-emulsion （ME） and emulsifiable concentrate （EC）, a formulation of cyhalothrin 3.0% ME had been prepared by using composite emulsifiers and n-butyl acetate as a solvent. The performances were in accord with the national standards by testing. [Methods] The effect of cyhalothrin 3.0% ME diluents with different concentrations on MDS, polydispersity index （PDI） and Zata potential were investigated by using a laser light scattering compared to a commercially available cyhalothrin 2.5% EC. [Results] It was found that the MDS of the ME formulation increased slightly with different dilution concentrations and was less than that of the EC formulation. Effect of standing time on the MDS of the ME formulation showed that the MDS was less than 100 nm after diluting different concentrations for 2 h. The two formulations were diluted to a concentration of 30 mg/L and then sprayed on the glass sheets, and observed by using a scanning electron microscope. [Conclusions] The EM formulation formed rod-like or bulk crystals with the crystal size ranged from a few microns to tens of microns, and the cyhalothrin 2.5% EC formulation formed dendritic crystals with the crystal size of about 50μm or more. It was adverse to play the pesticide efficiency.