Preparation And Properties Of Chlorpyrifos Microcapsules By Urea-Formaldehyde Resin

Compared with common pesticide formulations,microcapsules have many adavantages such as prolong controlling effect, improve using efficiency, avoid decomposition and invalidation, abate toxicity and harmfulness, reduce environment pollution, and so on. Chlorpyrifos was the replaceable insecticide of methomidophos and largely applied for controlling agricultural and pestiferous pests. However, chlorpyrifos have short field residual activity because of marked photodegradable effects, in addition,the main formulation of chlorpyrifos is EC, which consumed a lot of organic solvent, and resulted in environment pollution and resource waste, but chlorpyrifos microcapsules can avoid forenamed problems. So we have studied chlorpyrifos microcapsules with UF-resin via in-situ polymerization, obtained the optimal conditions of formulation and technics, and main contents is as the following aspests:1.For the screening the formulation of chlorpyrifos microcapsules, the optimal conditions were as follows: solvent was benzene, emulsifier was Styrene Maleic Anhydride(SMA), dispersant was PAAS,the dosage of benzene,SMA,PAAS were 5%,2.5%,2%,respectively, and added 0.4g sodium chloride. The effect factors on surface shape of microcapsules were also investigated, The results showed:Increased temperature rate at 10℃/20min to 60℃, fell rotating speed rate at 200r/min to 200 r/min and added 0.4% sodium chloride of total system in solidify time could prepare good surface shape of microcapsules.2.Study on the factors of particle size and distribution of microcapsules showed that the mean diameter and coefficients of variance of microcapsules were reduced early and appreciably augmented late with the dosage of SMA increased. When increased stirring speed and prolonged stirring time, the microcapsules particle size decreased and the distribution became narrow,but there no change when increased a limit. Anchor mill leaf superior than erection mill leaf, because it can give more cut power. PAAS can excellently decrease microcapsules size, but no effect on size distribution. When prolonged...