- Unsaturated oil coating material
Use oil as a layer material to make slow-release fertilizers. At least two coats should be sprayed on the fertilizer granules: the first layer is a highly viscous unsaturated oil, and the second layer is a low viscous unsaturated oil. The second layer serves primarily as a seal. Some ordinary drier should be blended into the oil before the coating. Suitable oils are: linseed oil, safflower oil, sunflower oil, soybean oil, etc. This type of coating material has a wide range of sources, renewable resources, and the coating is easily decomposed in the soil.
- Thermoplastic resin coating material
In the preparation process, a resin solution or melt is coated on the surface of the fertilizer particles to form a hydrophobic polymer film.
- Polymer resin in molten state
- Polymer resin dissolved in organic solvent
- A polymer resin formed by reacting two or more components on the surface of the particle
- Polymer resin (polymer dispersion or emulsion) dispersed or dissolved in water