Controlled-release fertilizer, and preparation method and application thereof

Abstract

The invention provides a controlled-release fertilizer, and a preparation method and an application thereof. The controlled-release fertilizer comprises a polyurethane coating material and an inorganic fertilizer, wherein the mass ratio of the polyurethane coating material to the inorganic fertilizer is (1-6): 1000. The controlled-release fertilizer has the following advantages: controlled-releaseperformance is excellent; modified castor oil and diisocyanate are used as main reaction raw materials of the polyurethane coating material; mechanical properties and processing performance of a filmlayer are improved through addition of a chain extender, an auxiliary agent and a catalyst; a formed polyurethane film layer has higher strength and good toughness; the controlled-release performanceis significantly improved; little influence is generated by the adhesion process in the process of processing; continuous coating film production can be continuously and stably performed; the initialdissolution rate is generally 2% or below; the minimum differential dissolution rate can achieve about 0.83%; the longest release period can achieve 70 days or above; and compared with a conventionalcontrolled-release fertilizer, the controlled-release fertilizer provided by the invention shows better mechanical properties, is free of the phenomenon of adhesion, and facilitates market application.

Description

technical field [0001] The invention belongs to the field of fertilizers and relates to a controlled-release fertilizer and its preparation method and application. Background technique [0002] Polyurethane-coated controlled-release fertilizers are prepared by directly mixing and reacting reactants such as polyols and isocyanates on the surface of fertilizer particles, involving many technologies such as polyurethane reactive materials, film-forming reaction processes and equipment. As far as coating materials are concerned, castor oil polyols and isocyanates are mainly used as coating materials at present. [0003] In 1961 and 1965, Hansen applied for a patent for the preparation of controlled-release fertilizers by the polymerization of polyols and isocyanates. Starting from this, the technology system using polyurethane as the coating material gradually developed into the production of controlled-release fertilizers. an important direction. However, until 1994, Alice P....

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Problems solved by technology

[0010] Aiming at the deficiencies of the prior art, the object of the present invention is controlled-release fertilizer and its preparation method and application, so as to solve the problems of the existing coated fertilizers with poor controlled-release effect and coating processing performance

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