Film Forming Mechanism of Color Coated Steel Coil
The coating film formation of color coated plate mainly includes coating adhesion and coating drying.
A Color coated plate coating adhesion
The first step of adhesion of steel strip substrate and coating is the wetting of color coated plate coating on the surface of the substrate. The wetting of coating can replace the air and water originally adsorbed on the surface of steel strip substrate. At the same time, the volatilization of solvent on the surface of the substrate can lead to dissolution or swelling. If the solubility parameters of the film forming resin of color coated plate coating and the surface of the substrate are properly selected, an immiscible layer will be formed between the surface of color coated plate substrate and the coating film, This is important for good adhesion of the paint.
B Color coated plate coating drying
The adhesion construction of color coated plate coating is only the first step of coating film forming in the coating process of color coated plate, and the process of turning into solid continuous film should be continued to complete the whole coating film forming process. This process from "wet film" to "dry film" is usually called "drying" or "curing". This drying and curing process is the core of the coating film forming process. Different forms and compositions of coatings have their own film forming mechanism, which is determined by the properties of film forming substances used in coatings. Generally, we divide coating film formation into two categories: solid and
(1) Non transformative. Generally, it refers to the physical film forming method, that is, it mainly depends on the volatilization of solvent or other dispersion medium in the film, and the film viscosity gradually increases to form a solid film. For example: acrylic paint, chlorinated rubber paint, ethylene paint, etc.
(2) Transformational. Generally, it refers to the chemical reaction in the film forming process, and the film forming of coatings mainly depends on the chemical reaction. This film forming is a process in which the film forming substances in the coating polymerize after construction, which is called the coating of polymer. It can be said that it is a special polymer synthesis method, and it completely follows the polymer synthesis reaction mechanism. For example: alkyd coatings, epoxy coatings, polyurethane coatings, phenolic coatings, etc. However, most modern coatings do not form films in a single way, but rely on a variety of ways to form films. Coil coatings are typical ones that rely on a variety of ways to form films.