Polyurethane coated controlled-release fertilizer with improved mechanical property, preparation method thereof and special coating material

Abstract

The invention discloses a polyurethane coated controlled-release fertilizer, a preparation method thereof and a special coating material. The coating material comprises modified isocyanate, polyalcohol and additive, wherein the mole ratio between hydroxyl (OH) in the polyalcohol and isocyanic acid radical (NCO) in the modified isocyanate is 1: 0.8-2.0; the polyalcohol is alcohol containing 2-6 hydroxies and has the molecular weight of 60-3000Da; and the additive is lubricating agent and/or toughening agent, and the adding quantity of the additive is 0.1%-20% of the mass of the modified isocyanate and the polyalcohol. The coated controlled-release fertilizer consists of a core and a core film, wherein the core is granular fertilizer, the core film is made of the coating material, and the mass of the core film is 1.0-10% of the mass of the core. The polyurethane coating prepared by the coating material can enhance the elasticity and the toughness of a polyurethane film layer and correspondingly improve the mechanical damage resistance performance of the coated fertilizer.

Description

technical field [0001] The invention relates to a film-coated controlled-release fertilizer and a preparation method thereof, in particular to a polyurethane-coated controlled-release fertilizer with improved mechanical properties, a preparation method thereof and a special coating material. Background technique [0002] Fertilizers, especially chemical fertilizers, are sources of nutrients necessary for crop growth. [0003] In recent years, slow and controlled-release fertilizers that can release nutrients slowly have been developed rapidly, including urease inhibitor type (ZL 99113382.X), urea-formaldehyde type, insoluble substance-encapsulated type (CN 85 1 01008, US 3342577), resin-encapsulated Membrane type (CN 89101193.5, US 4657576), etc. Through the adoption of the above-mentioned technologies, the moderate and uniform supply of crop fertilizer nutrients is ensured, while the loss of nutrients is reduced and the environment is protected. Among the above-mentioned ...

AI Technical Summary

Problems solved by technology

[0007] For polyurethane film coating technology, in order to improve the physical properties of the film layer, especially the impact resistance, Canadian Agrium company patent WO 2004 / 011395 introduced inorganic or organic fine powder into the polyurethane film layer, such as urea dust, phosphate rock powder, etc. , but the introduction of this external additive actually acts as a pore opening agent, which will inevitably make the water blocking performance of the film layer worse

In 2006, the company applied for the patent WO 2007 / 016788, which introduced epoxidized soybean oil into the polyurethane film material, and believed that it can significantly improve the impact resistance of film coating (the film layer accounts for less than 3.0% of the fertilizer) Performance effect, but the stability of this technology film layer in the soil may be problematic

Images