Developming And Evaluation Of Polyurethane Coated Urea Fertilizers

Polymer coating fertilizer could significantly increase fertilizer use efficiency, save energy and reduce pollution, which make it one of the reasons why it is the focus and the importance of the fertilizer researches. This study from polyurethane synthesis problem, studies the raw materials and modified material and additive on slow/controlled release fertilizers slow-releasing performance influence, on this basis of exploring the suitable coating process. The results were as follows:In this paper, It obtained the most suitable coating materials and their ratio: isocyanate Al:polyol B6=1:0.3.Adding different amount of additives for coating materials, conduct coating experiments, through the water dissolution rate experiments to evaluate the samples were screened by adding the appropriate amount of various additives. The results appear as:epoxy resin, xylene, dibutyl tin dilaurate and talc coating materials accounted for the percentage of the total, respectively:4%,0.05%and 5%. Then set the amount of different coating materials to experiment, selected the most suitable coating materials accounted for 7% of the total mass of products.The open switch pot was used in the coated process. The best speed of coated pot was 40 rev/hour, tilt angle was 25°. Fertilizer particle size should be 1.6-3.2mm, the surface temperature should be maintained at about 80℃. Feeding methods:the coated materials were divided into 1,2 components (the components of 1 were Al, polyol, leveling agent and xylene; 2 component was a catalyst) and then they were poured into the rotating coated pot in four separate doses.The corresponding initial dissolution rate of coated fertilizers was 2.34%, Nutrient leaching rate 34 days later was79%, in line with national standards...