A brief discussion on the film-forming mechanism of coatings

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A brief discussion on the film-forming mechanism of coatings: The application of coatings onto the surface of objects being coated constitutes merely the first step in the film-forming process. It is necessary for the coating to undergo further processes to transform into a solid, continuous film; only then can the entire film-forming process be completed. This process of transitioning from a “wet film” to a “dry film” is commonly referred to as “drying” or “curing”. This drying and curing process is the core of the paint film formation process. Coatings with different forms and compositions have their own film-forming mechanisms, which are determined by the properties of the film-forming substances used in the coatings. Generally, we divide the film-forming process of coatings into two main categories: (1) Non-transformative types, which refer to physical film formation processes, wherein the solid film is formed as the viscosity of the coating increases due to the evaporation of solvents or other dispersing agents present in it. For example: acrylic coatings, chlorinated rubber coatings, asphalt paints, vinyl coatings, etc. ⑵ Conversion-type: Generally refers to situations where a chemical reaction occurs during the film-forming process; in such cases, the coating forms a film primarily through a chemical reaction. This film formation process is the procedure in which the film-forming substances in paints polymerize after application to form a polymer film. It can be regarded as a special method of polymer synthesis, one that fully adheres to the mechanisms of polymer synthesis reactions. For example: alkyd paints, epoxy paints, polyurethane paints, phenolic paints, etc. However, most modern paints do not form a film through a single mechanism; instead, they rely on multiple mechanisms to ultimately form a film.