Method for producing reclaimed thermoplastic resin and thermosetting resin multi-layer composite coated controlled-release fertilizer

Abstract

The invention relates to a multi-layer composite coated controlled-release fertilizer with recycled thermoplastic resin as the inner coating and thermosetting resin as the outer coating and a production method thereof. In this invention, the recovered thermoplastic resin and a certain proportion of mineral powder and grain powder are mixed in a mixed solvent of n-butyl acetate and amyl acetate, and then sprayed on the fertilizer particles through a two-fluid nozzle in a heated fluidized bed. , forming a thermoplastic resin film with nutrient controlled release function. Then it is transferred to the heated drum fluidized bed, and the mixture of thermosetting resin, curing agent and diluent is sprayed in stages. Under the condition of rotating and heating, a rapid curing reaction occurs on the outer layer of the thermoplastic resin film to form a dense and bright film. thermosetting resin film. This product integrates the advantages of two types of resin films, realizes the perfect combination of toughness and elasticity, and can reduce the amount of film materials by 20-50% to achieve the same controlled release effect, which not only reduces the cost, but also improves the internal controlled release effect of the product and Appearance quality, suitable for large-scale industrial production and promotion.

Description

(1) Technical field [0001] The invention belongs to the field of slow and controlled-release fertilizer production. The solution of recycled thermoplastics is sprayed on the surface of compound (mixed) fertilizers or urea granules to form an inner coating, and then a thermosetting resin is used to cure the inner coating of the thermoplastic resin to form an extremely thin outer coating. A multi-layer composite coating controlled-release fertilizer with a layer reaction film and a production method thereof. (2) Background technology [0002] At present, the types of film-coated controlled-release fertilizers at home and abroad mainly include polymer-coated fertilizers and inorganic-coated fertilizers. Inorganic coated fertilizers are represented by sulfur-coated urea (SCU) (US3295950) developed by TVA Corporation of the United States. Although the production cost is not high, it is difficult to strictly control the release rate and time of its nutrients. Since the sulfur mem...

AI Technical Summary

Problems solved by technology

The controlled-release fertilizer coated with thermoplastic resin is represented by "Meister" and "Nutricote" produced by Japan's Chisso-Asahi Fertilizer Company. The coating material is mainly polyethylene and ethylene vinyl acetate copolymer (EVA) mixed in a certain proportion Finally, it is dissolved in an organic solvent, and then sprayed on the fertilizer particles in a fluidized bed coating tower to form a film. This coated fertilizer also has the function of nutrient controlled release, but the price of this resin is expensive, which makes the coated fertilizer The production cost and sales price are relatively high. In addition, the residual film after the fertilizer dissolves takes a long time to degrade in the soil.

Thermosetting resin-coated controlled-release fertilizers are mainly represented by "Osmocote" produced by Scotts in the United States. The coating material is alkyd resin or polyurethane polymer. This resin-coated fertilizer has good controlled-release performance and Appearance quality, but the price of this resin is expensive, so the cost of producing controlled-release fertilizers is too high to be widely used on field crops

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