A coating is a process in which layer of polymer or any material in liquid form used for depositing or covering the surface of the substrate. As per the Wikipedia the purpose of coating is decorative, functional or both. Decorative coating is done to achieve the aesthetic look and feel of material i.e. coating or painting on the fabrics with some artistic manner, on the other hand functional coating is applied achieve the adhesion, wetability, corrosion resistance, wear resistance, or water resistance.
The science of coating requires the understanding of the two phenomenon liquid flow and surface chemistry that deals with the solid to liquid relations. Study of viscosity and changed in the shape of liquid is very important in the process of coating.
Coatings are defined as mixtures of various materials. The materials are classified into four categories:
Techniques of the Coating:
Various coating techniques help in achieving the coating width of from thickness of some microns to mm, various coating techniques are as follows:
- Gravure Coating Machine
- Reverse Roll Coating Machine
- Knife Over Roll Coating Machine
- Air Knife coating
- Metering Rod (Mayer Rod) Coating Machine
- Slot Die Coating Machine
- Curtain Coating Machine
- Immersion/Dip Coating Machine
- Hot melt Coating Machine
- Web Coating Systems
- Fabric Coating Machine