Formulation Development For Oil-based Suspension Concentrate Of Two Kinds Of Sulfonylurea Herbicides

Both nicosulfuron and rimsulfuron are sulfonylurea herbicides,which are characterized by ultra-high efficiency,wide weed-control spectrum,long-lasting duration and low control cost.They are widely used and their sales are increasing year by year.At present,the main processing formulations of the two herbicides are oil-based suspension concentrate.But the popularization and application of nicosulfuron herbicides is severely restricted by the difficulty in formulation development,the poor product stability such as delamination and insufficient emulsification.In this paper,an optimized formulation of 8%nicosulfuron oil-based suspension concentrate and 20%rimsulfuron oil-based suspension concentrate were obtained through adjuvants screening,which provided reference for the preparation of sulfonylurea herbicide oil-based suspension concentrate.In this study,the adjuvants were screened by the flow point method,and then the optimal formula was selected by orthogonal test method and triangular coordinate method respectively.At the same time,the problems existing in the industrial scale of the formula were summarized and corresponding solutions were proposed.The optimal formulation of 8%nicosulfuron oil-based suspension concentrate obtained by orthogonal test was as follows:8%nicosulfuron,2%dibenzoxazole,10%emulsifier VO/02N,5%emulsifier BY-125,3%dispersant D-425,2%anti-decomposition agent TO-8,1.5%organic bentonite and 2%fumed silica,and methyl oleate made up to 100%.The optimal formulation of 20%rimsulfuron oil-based suspension concentrate obtained by the triangular coordinate method was as follows:20%rimsulfuron,10%dibenzoxazole,7.5%emulsifier Termul 3016,6%emulsifier Alkumuls 696,3%dispersant Terperse 5500,2%anti-decomposition agent TO-8,1%organic bentonite and 1.5%fumed silica,methyl oleate was made up to 100%.In the process of industrialization amplification,the problem of agglomerates in the material was solved by adjusting the feeding sequence,by increasing purity,reducing structural stabilizer,increasing the amount of the auxiliary agent,controlling temperature to solve the problem of high viscosity after grinding,and adjusting the particle size of the grinding medium,pulverizing technical herbicide in advance,and lowering the feeding speed of the grinder to solve the problem of wide particle size distribution.