Study On Using High Vinyl Silicone Oil-Modified Acrylic Eemulsion To Prepare Coated Slow/Controlled Release Fertilizer

Coated slow/controlled release fertilizer has become the development direction of the world fertilizer,as the top priority,coating materials also aroused the interest of many researchers.Wherein the research of using the organic resin as the coating materials attracted more and more attention of scientists.The organic resin is divided into two categories,namely organic solvent-based resin and aqueous organic resin,however,as people’s awareness of environmental protection,solvent-based organic resins gradually being left out because the VOC emissions in the production process is not up,in this case,the aqueous emulsion attracts more and more attention because of its excellent performance and environmental advantages.In this paper,the main content is the preparation of the new coating materials.first of all,we use high vinyl silicone oil to modify acrylic emulsion polymerization,explore the optimum conditions for preparing the emulsion;later,adding a variety of hydrophobic agent in the modified emulsion to determine the respective optimum amount of hydrophobic agent,to prepare coated slow / controlled release fertilizers which having a good slow/ controlled release effect and low cost.Using pre-emulsified semi-continuous seeded emulsion to prepare solution of high vinyl silicone-modified acrylic emulsion polymerization.The effects of the type of catalyst,monomer ratio,the amount of high vinyl silicone oil,oil-water ratio,the amount of initiator and holding time on the appearance of the emulsion,solids content,viscosity,film characters and the fertilizers’ slow/controlled release properties were searched,the best preparation process to obtain an emulsion is as follows: after adding high vinyl silicone oil as the modifier,choosing APS(ammonium persulfate)as the reaction initiator is better;MMA(methyl methacrylate):BA(butyl acrylate): MAA(methacrylic acid)mass ratio is 42:54:4;high vinyl silicone oil’s optimum amount is 9% of the total mass of the monomers;water mass ratio is 100:125;ammonium persulfate optimum amount of raw materials for the total mass is 0.55%;holding time is 1h.Three aqueous emulsion water repellent were made in the laboratory,and added to the high vinyl silicone-modified acrylic polymer emulsion,the impact of the addition amount of the hydrophobic agent on the emulsion appearance,fertilizers’ appearance,film content and the slow / controlled release properties was studied,and the optimum amount of the three kind of hydrophobic agent is as follows:microcrystalline wax water repellent’s optimal addition amount is 8% of the emulsion total mass;polyethylene wax emulsion water repellent’s optimal addition amount is 8%of the emulsion total mass;silicone hydrophobic agent’s optimal addition amount is 4%of the emulsion total mass.Eventually,The initial nutrient release rate of the coated slow/controlled fertilizer is 13% which meets the GB/T 23348-2009 requirements.