| 摘要 |
PURPOSE: Provided is a method for producing a controlled-release granular coated fertilizer, which can release fertilizer ingredient in a short time at room temperature or lower temperature constantly, especially at low temperature, using the highly water-absorptive resin without loss, and suppressing the by-production of fine particles coated only with the highly water-absorptive resin. CONSTITUTION: The method comprises, in order, the following steps of: (1) adding a water-absorptive polymer to a granular fertilizer; (2) placing the granular fertilizer in a tumbled state; (3) adding liquid uncured urethane resin to the tumbled granular fertilizer in an amount enough to secure a layer thickness of 1 to 10 micrometer; (4) coating the surface of each granular fertilizer in the uncured urethane resin while keeping the granular fertilizer in the tumbled state; (5) curing thermally the urethane resin while keeping the granular fertilizer in the tumbled state to form a urethane resin layer; and (6) repeating the above steps (2) to (5) one or more times, in this order.
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