| Maize is one of the most important crops in China and the world, and can be used as feed and industry materials. The pests and diseases on maize can make a big reduction in maize production and can greatly affect product's qualities. Recent years, Carbofuran?Thiram 15%FS , a present product of new complex flowable concentrate for maize seed coating , has been applied to process maize seed to control maize's pests. But most of present Carbofuran?Thiram FS products are not satisfied and have many problems in such as suspensibility, formulation stability and film-forming.This paper studied the preparation of Carbofuran?Thiram 15%FS, also studied the analytic methods of the formulation product, and determined the properties of the formulation. We also studied the formulation processing technology and improved processing conditions and optimized the formulation processing adjuvants.1. Wetting-dispersing agent E, Wetting-dispersing agent B and Wetting-dispersing agent D were elementarily screened out of sixteen surfactants using the method of flow point and viscosity curve, and the best dosages of the wetting-dispersing agent were determined. Orthogonal design and analysis were used to optimize the wetting-dispersing agents,.The effects on suspensibility were Wetting-dispersing agent E>Wetting-dispersing agent B >Wetting-dispersing agent D . The optimizing formula of wetting-dispersing agent consists of Wetting-dispersing agent D 2.5%, Wetting-dispersing agent B 1%, Wetting-dispersing agent E 2.5%.2. We studied different thickeners'properties by comprehensively checking the viscosity, stability after centrifuging, heat storage stability and pouring property in the best wetting-dispersing agents'formula. The suitable thickener for carbofuran·thiram 15%FS was selected preliminarily. The result indicated that the mixtured thickener A consisting of thickener A and thickener B had an optimum efficiency. And some natural thickeners commonly used in foods and pharmaceuticals (e.g.Arabic gum, artemis sphaerocephala krasch gum(ASK gum), fenugreek gum and and thickener-FDY) also demonstrated hopeful application prospects in flowable concentrate for seed coating.3. By checking the viscosity, pourability, heat storage stability, filming time and ratios of drop, we choiced the membrane-forming. Our result indicated that the mixtured membrane-forming A that we specially prepared consisting of membrane-formingA and membrane-forming B demonstrated excellent properties.4. The option of antifreezing agent we did by checking external appearance of the formulation, flowability and suspensibility in -5℃test.The result indicated that ethylene glycol was suitable.5. We finally optimized the formula by orthogonal design and orthogonal analysis. The maximal effects on layered rate and suspensibility were the mixtured thicker agent A and the mixtured membrane-forming A respectively. Adding the new wetting-dispersing agent F could reduce the usage of the other surfactants greatly;After heat storage, the suspensibility could reach 96.41% and the layered rate was only 0.5%.6. After adjusting the pH, we determined the optimized formula was Thiram 7.0%, Carbofuran 8.0%, mixtured wetting-dispersing agent 4.5%, mixtured thickener A1.2%,mixtured membrane-forming 0.5%, ethylene glycol 5%, rhodamine 0.5%, 36%hydrochloric acid 0.1%, added water to 100%. The formulation processing method had been studied, the formulation processing method of wet milling was improved.7. We determined all the properties and the quality indexes of Carbofuran?Thiram 15%FS that we prepared using our processing method (including external appearance, contents of the active composition, pH, suspensibility, viscosity, membrane-forming, seed coating, ratio of drop, low temperature stability, heat storage stability, dispersity, centrifugal stability, pourability by the national standard methods of pesticide. The results showed that the sample of Carbofuran?Thiram 15%FS we prepared had a very good quality.
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