Thermoset coat surrounding plant nutrient, further coated with a sulphur layer followed by another thermoset layer for slow release fertiliser

摘要

A controlled release fertiliser composition comprising a water-soluble central mass of plant nutrient compound in particulate form, a first thermoset polymer coating on the plant nutrient, a layer of elemental sulphur on the first thermoset polymer coating and a second thermoset polymer coating on the elemental sulphur layer. In the preferred embodiment, a coat with reactive monomers to form a thermoset polymer and while the polymer is still hot, molten sulphur is sprayed on to the formed polymer layer to form a sulphur layer. A second polymer layer is then applied to the sulphur layer.