The Development Of2,4-D-butylate Microencapsulated Suspension

Microcapsule suspension compared with conventional formulations of pesticides, micro-capsules have extended the persistence of the pesticides,improve the effective utilization of pesticides, reduce the loss of the decomposition of pesticides, reduce toxicity and injury, reduce environmental pollution and so on.At present, the micro-capsule suspension formulations is the most successful controlled release dosage forms for plant protection. Therefore, the microcapsule suspension is becoming a way to the development of the new pesticide formulation.2,4-Butyl (2,4-D-butylate) and its derivatives is a selective herbicide for the type of the acetic acid and the uptake sex hormones, is one major herbicides for China, It is used for a long time and the amount of application is very large at the worldwide.In this study, the urea-formaldehyde resin as the material of wall, Using the in-situ polymerization method for2,4-D-butylate microcapsule suspension formulation, screening a better system into the capsule, and studied2,4-D-butylate microcapsule suspension performance and its impact factors, in order to optimize the best process conditions.Studied the effects of the urea-formaldehyde resin as the material of wall for2,4-D-butylate microcapsule suspension formulation what include the dispersion emulsifier, the conditions of emulsifying process and the technology of microcapsule. Through compared with the effects of the different conditions for making microcapsules under the surface morphology, the encapsulation efficiency, the particle size and the situation of distribution, determine a suitable emulsifier and their ratio, the curing agent, the ratio of capsule wall and heart, the end of PH, the stirring speed, the acidification time, the curing temperature and curing time.Processing technology:mixed emulsifier A and emulsifier B ratios were3.5:6.5(mass ratio) as emulsifier, citric acid as a catalyst, and the capsule wall and heart ratio was1.7:1, the end pH was2.0, the acidification time was2.0h, the curing temperature was40℃, the curing time was90min, the stirring speed was2500rpm curing/min.Under these conditions we can get the better surface morphology of microcapsules, it was the spherical microcapsules,the average particle size was2.176um, the particle size distribution concentrated and uniform, the encapsulation rate more than89.746%.On the based of the best technology of the microcapsule in the above, we can obtain the30%2,4-D-butylate microcapsule suspension for adding suspension dispersant,and had determined the particle size distribution, the encapsulation rate, the hot and cold storage stability, the dumping and other quality control indicators, and the suspended rate more than96.692%.Through the experiment, the impact of measurement results of the encapsulation efficiency of microcapsules, the active ingredient content preparation, the suspension rate, the analysis of water rates and other indicators with heat storage and cold storage have showed that:Through the hot and cold storage, the rate of microcapsules encapsulation is still more than86%, the rate of preparations suspended more than92.3%, the water analysis rates around of1.08%, indicating that the product has good physical and chemical stability.Determining the slow-release performance of the2,4-D-butylate microcapsule and2.4-D microcapsule suspension in methanol-phosphate buffer system.and determining the slow-release performance of the2,4-D-butylate microcapsule and2,4-D-butylate microcapsule suspension in the air and the seal environment through the column chromatography, compare these results to illustrate.The results show that the law of2,4-D-butylate microcapsule suspension releasing fit with a stair kinetic equation. The drug efficacy of2,4-D-butylate micro-capsules is the2,4-D-butylate original several times on the same conditions, indicating that the2,4-D-butylate micro-capsules with good release properties. Thus,2,4-D-butylate microcapsules with the fast release speed in the initial, then, in the difference concentration of2,4-D-butylate where are inside and outside of the microcapsule have had reductioned, and the release rate have had decreased.Finally, the same concentration inside and outside of the microcapsule, the capsule core is no longer releasing. May be due to having a larger wall of2,4-D-butylate in the micro-capsules and the concentration of2,4-D-butylate which the external environment of micro-capsules is zero in the early treatment, so in the difference concentration of2,4-D-butylate where are inside and outside of the microcapsule is the maximum in the process of releasing, so the materials of capsule core are fastest releasing.The experiment of pots, use72%2,4-D-butylate EC as a contrast agent, determining the control effects of quinoa and other weeds by the30%2,4-D-butylate microcapsule suspension at the initial and after planting few days, analysising the different defense rates of the fresh weight and the plant weight in the two different formulations.The results showed that:Initial,the defense rates of the quinoa and other weeds’ fresh weight and the plant weight by72%2,4-D-butylate EC with the processing dosage of50ml/667m2and75ml/667m2,and at the same concentration that are higher than handled30%2,4-D-butylate micro-capsule suspension, but the difference was not significant.After spraying a few days30%2,4-D-butylate microcapsule suspension is still controling weed. This also verified that the2,4-D-butylate microcapsule suspension has good release properties, the2,4-D-butylate microcapsule suspension can release fully and there is a good support function in the environmental system.