Abstract: color coated plate, also known as color steel plate, is a product made of cold-rolled steel plate and galvanized steel plate as the substrate, through surface pretreatment, roll coating + baking process, continuous coating, baking and cooling.
Color coated plate, also known as coated plate, is a building material made of metal coil as the base material and coated or laminated with various organic coatings or plastic films on the surface. The base material types of color coated plate mainly include:
The color plate produced from cold-rolled substrate has smooth and beautiful appearance and processing performance of cold-rolled plate; However, any small scratch on the surface coating will expose the cold-rolled substrate to the air, resulting in red rust at the exposed iron quickly. Therefore, such products can only be used for temporary isolation measures with low requirements and indoor materials.
The product obtained by coating organic coating on hot-dip galvanized steel plate is hot-dip galvanized color coated plate. In addition to the protection of zinc, the organic coating on the surface of hot-dip galvanized color coated plate also plays the role of isolation protection and rust prevention, and its service life is longer than that of hot-dip galvanized plate.
The zinc content of hot-dip galvanized substrate is generally 180g / ㎡ (double-sided), and the maximum zinc content of hot-dip galvanized substrate for external use is 275g / ㎡.
The product obtained by coating organic coating on hot-dip aluminum zinc steel plate is hot-dip galvanized color coated plate, in which the content of aluminum and zinc in hot-dip aluminum zinc steel plate is 55% AI Zn and 5% AI Zn.
The product obtained by baking with the electro galvanized sheet as the substrate and coated with organic paint is the electro galvanized color coated sheet. Because the zinc layer of the electro galvanized sheet is thin and the zinc content is usually 20 / 20g / m2, the product is not suitable for making walls and roofs outdoors.
However, due to its beautiful appearance and excellent processing performance, it can be mainly used for household appliances, acoustics, steel furniture, interior decoration, etc.
For the color coated steel plate with galvanized steel plate as the substrate, in addition to zinc protection, the organic coating on the zinc layer plays a role of covering and isolation, which can prevent the steel plate from rusting, and the service life is longer than that of galvanized steel plate.
It is reported that the service life of coated steel plate is 50% longer than that of galvanized steel plate.
Color coated steel plate is widely used. Because it has the characteristics of no pollution, excellent weather resistance, corrosion resistance and high processing, color coated steel plate is widely used in construction, household appliances, transportation, packaging, machining, interior decoration, medical treatment, automobile industry and other industries.
The substrate is degreased and washed, then phosphated or composite oxidized to form a layer of phosphate or composite oxide film on the surface of the steel plate, and then passivated and closed. The formed pretreatment film is an effective means to improve the adhesion between the substrate and the coating.
The color coating unit generally applies the coating on the surface of the strip steel by roller coating, that is, first form a film with a certain thickness on the roller, and then transfer the coating to the surface of the strip steel. In the process of coating, the coating thickness can be adjusted within a certain range by adjusting the roller gap, pressure, the pressing force between the coating head and the strip steel and the roller speed; It can be painted on one side or both sides at the same time.
After coating, the coating also needs to be cured. This process is a process in which the main film-forming substances, auxiliary film-forming substances and curing agent in the coating undergo chemical polycondensation, addition polymerization, cross-linking and other reactions through solvent volatilization under certain temperature conditions, and change from liquid to solid. Coating curing generally includes initial coating baking, fine coating baking and corresponding waste gas incineration system.
The subsequent processing of color coated steel plate coating includes coating embossing, metal printing, printing, film coating and other treatment methods.
It can also be waxed or added with protective film to avoid scratching of color coated steel plate during handling or processing.