The chemical film-forming mechanism of coatings for PPGI Steel Coil refers to polymers or low molecular compounds that can be cross-linked when the coatings are cured to form a film. After the coating construction, a cross-linking reaction occurs between them to form a cross-linked polymer to form a film. Coatings that form films by chemical mechanisms can be divided into two categories.
(1) Oxidative polymerization type. Oxidative polymerized coatings are mainly oil or oil-modified coatings, which form a reticulated macromolecular structure through an oxidative cross-linking reaction with oxygen in the air. The speed of oxidative cross-linking is related to the number of carbon-carbon double bonds in the resin molecule and the geometric configuration of carbon-carbon double bond substituents. Adding a drier can speed up the cross-linking speed.
(2) Condensation reaction type. A reaction in which two or more organic molecules interact by covalent bonds to form a macromolecule while losing water or other relatively simple inorganic or organic small molecules. The resin with large relative molecular mass and linear molecular structure in the coating system can be cured to form a film by condensation reaction to form a cross-linked network structure called condensation reaction type film formation. Phenolic resin coatings, amino alkyd resin coatings, etc., are formed into films through condensation reactions.
In the production of color-coated steel plates, one type of film-forming type is mainly used. After coating, the above types can initiate and accelerate the cross-linking reaction, and the film can be cured quickly, which can meet the needs of high-speed production units. Requirements.