| Zn thiazole was a novle created fungicide jointly developed by Zhejiang XinNong Chemical co., Ltd, and Zhejiang University of Technology. In order to enrich of Zn thiazole’s formulation, in this paper, the recipe, processing technology, and the effect of additives and processing technology on the properties and biological activity of Zn thiazole water dispersible granule were studied.The preparation of 60% WG Zn thiazole was studied. Carrier used directly after mixing with technical method. By testing the solid substance’s suspension rate, the optimal carrier, bentonite, was screened from 8 kinds of carrier screening. Flow point method was adopted to screen wetting agents. By using flow point method, we found that KR-06’s wet ability was the best among 11 kinds of wetting agents. By comparing the suspension rate of high and low, the optimum dispersant KY-816 was gained from selection of 11 kinds of dispersants. By comparing the different dosage of disintegration time, sodium carboxymethyl starch was screened from the four kinds of disintegrating agent. In addition, through test lasting foamability, G-20n was screened from four defoamers. Chemical stability test showed that Zn thiazole was thermal stability, and there was no need to add any chemical stabilizer in the preparation. Through the experiment, the recipe of Zn thiazole 60% WG was as follows:Zn thiazole (a.i.) 60%, KR-06,2% KY-816,6%, sodium carboxymethyl starch 3%, G-20n,0.4%, bentonite to fill to 100%. Using the above recipe, physical and chemical performances of Zn thiaozle 60% WG was excellent.We compared the performance difference of two Zn thiazole 60% WG samples. One sample was prepared by rotary extrusion granulation, and the other was prepared by boiling granulating. Experiment showed that the optimization of rotary extrusion granulation process condition was:water content 20%-25%, 1mm mesh size, vacuum drying temperature of 50℃-60℃, drying time of 0.5h-1h. Optimization of process conditions of boiling granulating was:blower 20 hz frequency, inlet air temperature of 50℃, and spray droplet of water or adhesive solution were small. There was a big difference in hardness and in collapse between the two kinds process’s products. Products prepared by the rotary extrusion granulation had better hardness, and it was not easy to break into powder form, but its collapse was in general; Products prepared by the boiling granulating were oppsite. In addition, using boiling granulating production, rate of finished products was low.In terms of fertilizer’s effect on the performance of agents, wetting agent and dispersant play a key role. Test showed that wetting agent not only exerted directly on the wettability of water dispersible granule and the main effect, but it also had indirectly influence on the performance of the water dispersible granule disintegration. Within a certain amount of usage it resulted in ascension of disintegration.In case that variety of dispersant was not the same, the suspension rate had a bigger difference.We studied the influence of the adjacent ondiluting stability of Zn thiazole WG. The study found that the change in dosage of wetting agent affected litter of diluent stability. The change of the dosage of dispersant had a greater influence on the stability of diluent. The influence to the stability was obvious referring to change in dilution multiples.The biological activity of Zn thiazole preparations on rice bacterial brown streak disease (P.syringae pv. panici (Elliott) Young et al.) tested by seed exposure pot culture method. EC50 of Zn thiazole 60%WG was 507 mg a.i./L, and EC50 of some Zn thiazole SC were 542 mg a.i/L,217 mg a.i./L,605 mg a.i./L and 503 mg a.i./L, respectively. The results showed that there was no significant difference in the biological activity between Zn thiazole WG and Zn thiazole SC. |
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