Dispersion
Dispersion coating is a process where aqueous polymer particles in water stabilised by wetting agents, are applied onto the surface of a substrate to form a continuous film after drying. The application is usually dried, baked and sintered in a three-zone vertical oven.
This type of coating offers a practical method for coating using polymers that do not respond to traditional solvent or melt-processing techniques.
It’s ideal for thin, uniform coatings and complex geometries.
Materials
- PTFE → The most common dispersion coating material. Applied as an aqueous dispersion and sintered to create a low-friction, chemically inert surface. Ideal for non-stick and anti-corrosion applications.
- PFA → Applied via dispersion where higher film integrity and improved permeability resistance are required. Offers similar chemical resistance to PTFE but with better film cohesion after sintering.
- ECTFE → Used in dispersion form for corrosion protection, particularly in chemical processing environments. Provides excellent barrier properties and good mechanical strength.
- Ceramic → Applied as a liquid ceramic-based dispersion. Forms a hard, inert coating with high temperature resistance and good abrasion performance, often used where a tougher alternative to fluoropolymers is needed.
Key Characteristics
The coating material is typically a polymer or other compound dispersed in a liquid, usually water or an organic solvent. The dispersion ensures that the particles are uniformly distributed in the liquid before application.
The dispersion can be applied to the substrate using various methods, such as spraying, rolling, or dipping. After application, the liquid component evaporates, leaving behind a solid coating.
Depending on the materials used, the coating may require curing through drying, heating, or UV exposure to solidify and adhere properly to the substrate.
Dispersion coatings are used to provide specific functions like corrosion resistance, waterproofing, heat resistance, or enhanced aesthetics.
