| In the last 10 years, much progress has been made in the design and development of new formulations. In particular, by reduction of organic solvents in liquid formulations, the environmental impact and toxicity of products may be reduced. For several years, studies on pesticide formulation technologies in China have particularly focused on mimicry and mixture, and few efforts have been paid on creation of new formulations, methodology of formulation, mechanism of suspension and emulsification, zeta potential, and rheology. Among crop protection agents, formulations for the treatment of seeds have became established during the last 10 years in the world, and are becoming an increasingly important aspect of crop protection agents application practice; however it has been made a small step in China. There is an increasing need for the crop protection industry to continue to develop seed coating products, which are optimized with regard to safety, environmental behavior, biological performance, and cost. Therefore, this study particularly emphasizes on critical technologies to produce seed coating agents. 1.The electrokinetic behavior of suspo-particles determines the storage stability of the solution. The stability of the suspension formulation might be ameliorated through using proper anionic surfactants, regulating pH values, and tying in very non-ionic surfactants. The electrokinetic behavior of suspo-particles in solution and the physical characteristics of suspension formulation were affected by these factors including solution pH value, anionic surfactant, and non-ionic surfactant, of which pH and anionic surfactant were dominant factors. Based on the experiment observation, non-ionic surfactant was an assistant. The electrification and potential of the solution were optimized by regulating pH values to escape iso-electric point and to increase electric repulsion. As an improver, the anionic surfactant could provide outer charges for suspo-particles, and thereby improved the electrification of the solution . The non-ionic surfactant indirectly influenced potential difference via forming a thicker slide layer with particles. 2. Based on the comparison of drop-point, viscosity curve, emulsifiability and dialysis methods, a set of method for screening surfactants for suspo-emulsion seed coating agents was developed as follows: 1) The emulsifiability method was suitable for screening of emulsifiers and for evaluating anionic surfactants and non-ionic surfactants. 2) Suspo-dispersants could be screened by the drop-point method, and the proportion of dispersants was determined by viscosity method. 3) The dialysis method was more suitable for testing the proportion of non-ionic surfactants and for identifying bond of particles. These methods, including viscosity curve, emulsifiability and dialysis, are available to evaluate the interaction between different surfactants; however, the selection of a specific method for screening should be based on the experimental purpose. 3. The liquid casting modification technique was firstly introduced into the study of pesticide formulation in this dissertation. The technique straightened out the contradiction between penetrate ability and water-proof ability of membraning agent for seed coating. L-tube method was developed to test the penetrate and water-proof abilities of the film. Compared with methods from GB11175-2002 and GB15330-94, the L-tube method is more feasible and easier. The results showed that the mixed system with poly vinyl-alcohol (PVA) and vinyl acetate-ethylene (VAE) contained hydrogen bond. In the mixed system, the micell of PVA was broken, and the interface between PVA and VAE was not observed. The result indicates PVA and VAE in the missed system were compatible and the membraning agent from this study matches the requirement for application. The bioassays showed that the film had no influence on the germination of seeds. 4. In this study, concepts and methods from rheology were applied into the research of suspo-emulsion formulation, including rheo-curve, rheological model and thixotropic methods. The result showed that the fipronil & prochloraz suspo-emulsion seed coating agent belongs to plastic liquid. The lower dosage of Xanthan gum (XG) could provide good apparent viscosity for the agent, and made the agent system become poseudo-plastic. The further thixotropic capability assay indicated that the XG significantly improved the thixotropy of the agent system. Consequently, the stability of the agent was improved. 5. The product, 7.5% fipronil & prochloraz suspo-emulsion seed coating agent, was successfully developed. The combo was: DBS, 1.5wt% + NR1601, 2.0wt% + Fipro. 5wt%)B1(DBS, 1.0wt%AEO-8, 1.5wt%+Proch. 2.5wt%)C(VAE/PVA=30/70wt%+Rhoda. 0.7wt%+XG. 2wt%. During the processing procedure, 5 h grinding could reach the economic balance point. Reverse-phase operation was used to produce prochloraz solution. The critical stability, particle size, centrifugal stability, degradation rate, and suspension rate of this product were 0.982, 0.16, 2.03, A, Pass, 98.9, and 98.7, respectively. All indices were equal or higher than those of normal products. The lose rate and evenness of the agent were 0.92wt% and 96.22%, respectively. The product had free influence on the germination ofseeds. The 7.5% fipronil & prochloraz suspo-emulsion seed coating agent had high efficacy against pests in the seedling of rice. The field assay showed that the agent could well control rice weevil (Echinocnemus sguovneng) and rice leaf beetle (Oulema oryzae),with the control values of 80.6% and 73.8%, respectively. The control efficiency was higher by 20% and 19% against rice weevil, as well as 5% and 9% against rice leaf beetle than 5% fipronil suspension concentration and 4.5% carbofuran granule, respectively. The product was bioactive against bakanae disease (Fusarium moniliforme), with control values 94.2% and 100% in seedling and tillering of rice, respectively. The control efficiency was higher by 6% and 7% than 25% prochloraz EC, respectively. Compared with suspension concentration and granule formulations, the suspo-emulsion seed-coating agent had theses characteristics including long persistence and controlled releasing. 6. Based on the above results, the technics proposal for producing 7.5% fipronil & prochloraz suspo-emulsion seed coating agent was developed. Compared with the colloid mill-beading grind kettle technics in the same production scale, technique and economic indices were partially improved. The producing technics has been successfully undertaken the pilot demonstration in 2 seed coating agent factories. These studies and practices will greatly contribute to massy production of 7.5% fipronil & prochloraz suspo-emulsion seed coating agent.
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