Whenever we think of architectural coating, it basically includes sealers, paints and specialty coatings aimed for building as well as construction applications. The main purpose of architectural coating is to function as a protective or decorative layer shielding the exterior of an architectural feature, be it indoor or outdoor.
Most of these coatings are applied on the surfaces using sprayers, brushes, rollers and other applicators. These are usually available in powder particles; there are certain liquid film coatings which are later converted to solid film coatings via specific film drying processes including cross-linking, coalescence, evaporation or fusion bonding. Let us try to understand these methods in-depth for precise knowledge.
Cross-Linking
Cross-linking, as the name suggests, points out to the process during which the polymers react to develop a long chained network. As a result of this linkage, the construction of larger polymers that can effectively create a sheet on the substrate is made possible. At present, several different coating technologies depend on polymer cross-links towards the generation of film formation. These include moisture-cured coating, multi-component coatings and radiation-cured coatings.
Fusion Bonding
This particular technique includes purely solid particles, quite commonly powders. Initially, these solids are coated over the substrate with the help of electrostatic spray. Later, the particles get fused by heating in order to create a continuous film. The different technologies that make use of fusion bonding are thermoplastic coatings, moisture-cured coatings and thermoset coatings. Considering the architectural coatings market, the inclusion of fusion bonding is gaining prominence due to its effective results.
Evaporation
This process is majorly based on low solids content together with large quantities of organic solvents. You can find evaporation method commonly used in many lacquers and spray paints. However, it stays highly regulated due to the high levels of solvent which get released into the atmosphere. As a result, this evaporation method is usually preferred in combination with cross-linking – inhibitors.
Coalescence
Coalescence points out to the flowing together of polymer particles during suspension, thereby, generating a clear polymer film. It is when small polymer particles are shaped during dispersion in water or probably an organic solvent right after exceeding the glass transition temperature for the polymer. Suppose the polymer stays below its glass transition temperature, then a coalescent (coalescing agent) could be added in order to reduce this property and support film formation. Latex based polymers are the common varieties in which coalescence takes place.