Coating is used for applying a fine, uniform layer on a pellet, granulate or powder, which protects the particle for example against external influences. These influences include light, oxygen (oxidation) or moisture. The particles can be covered with a coating layer to enhance their visual appearance or to provide colour differentiation. Apart from the application for masking odours or taste, functional coating can be produced which allows a time-delayed or pH-value depending release of the active substance.
The particles are wetted with coating liquid in the air flow of the fluidised bed plant. The film is formed in several layers and ensures a homogeneous, stable coat around the separated particle. Depending on the required product quality the processes are operated batch-wise or continuously by top- and bottom-spray methods as Wurster processes or by the NEUHAUS Spouted Bed Coating method.
Example of application: Fat coating for hydrophobic surfaces
A hydrophilic powder is stabilised by fat coating, the reduction of water absorption improves the storage stability and the flow properties of the product which has been conditioned in this way.
Intentional release or protection of active substances, masking of taste / odour, enteric coating, oxidation protection
Examples of products:
- Seeds and pesticides
- Pharmaceutical pellets or granules
- Sugar + fat or colouring agent
- Polymer coating
- Cereals + chocolate
- Thermal resitance of feed additives