Building And Studies On The Stability Of Suspension Concentrate Of Imidacloprid With Thixotropy

Suspension Concentrate (SC), a newly developing pesticide formulation and involving many theories, has no practical method in the surfactant selection and the specialized surfactants. Therefore bleeding, thickening and sedimentation have been resulted in SC formulation storage. Pointing at this fact, the Imidacloprid SC with thixotropic has been studied.First, based on the flowing point test and its common dosage scope, the experiment was conducted by the orthogonal design to select the proper surfactants and their dosages. Then the high viscous attapulgite, common attapulgite, magnalium silicate and bentonite, which could form a thixotropic structure in the dispersion system, were added in the 30% Imidacloprid SC to study the strength and the restructure ability of the thixotropic structure. Later the 3 common antifreezing agents were studied. The results show that the thixotropic structure and the dispensability are not only mainly related to the mineral categories and its content but also to antifreezing agent, which can better them under the proper mineral contents. At the same time, it was found that the results of centrifuge stability of suspension concentrate were not greatly related to the realities of the preparation stored in the room temperature.Secondly, the influences of PEG 6000 or methylcellulose, XG, magnalium silicate or bentonite and mass ratio of disperse phase on the Imidacloprid SC have been studied. The results show that on the study levels the influences of PEG 6000, Imidacloprid and XG on the restructure of the thixotropy structure all are significant at the a_0.25 level and the influences of XG and Imidacloprid on the dispensability are significant at the ao.10 level and at the a_0.25 level respectively for the magnalium silicate-Imidacloprid SC, and that for the bentonite-Imidacloprid SC, the influences of Imidacloprid and XG on the dispensability are significant at the ao.10 level, and the influences of methylcellulose on the restructure of the thixotropy structure after storage in 0℃ or 25 ℃ and on the dispensability all are significant at the a_0.25 level, and which contents have different effects on the both, that is, the dispensability becomes bad by added its contents but there is a proper content for the good thixotropy structure.Finally, the Rheology of the Imidacloprid SC with various magnalium silicate was studied. The results show that the suspensions have shear-thinning and their Rheology indicators have no linear relationship with the content of magnalium silicate.In a word, to making SC with proper thixotropic structure is a good solution to its storage problems and the orthogonal design could reduce the experimental time and cost, so it was an ideal method for the studying of pesticide formulation.