PPGI coil is also known as prepainted galvanized steel belt and prepainted galvanized steel plate, characterized by complete specifications, diverse materials; High dimensional accuracy, up to ± 0.1mm;Excellent surface quality, good brightness; Strong corrosion resistance, high tensile strength and fatigue strength; Stable chemical composition, pure steel, low inclusion content, widely used in construction, shipbuilding, vehicle manufacturing, machinery manufacturing, furniture and household appliances industry, electrical and automation industry.

Color coated plate structure

Finish paint: shield the sun, prevent ultraviolet damage to the coating; Finish paint can form a dense shielding film when reaching the specified thickness, reducing water permeability and oxygen permeability;
Primer: conducive to strengthen the adhesion of the substrate, so that the paint film is not easy to happen after water permeation paint desorption, but also improve corrosion resistance, because the primer contains corrosion inhibitor pigments, such as chromate pigments, so that the anode passivation, improve corrosion resistance;
Coating: generally galvanized or aluminum zinc plating, this part of the service life of the product has the greatest impact, the thicker the coating corrosion resistance is better;
Substrate: generally for cold rolled plate, different strength determines the mechanical properties of color coated plate can withstand;
Back paint: the function is to prevent corrosion of steel plate from the inside, generally two layers of structure (2/1M or 2/2, primer + back paint), if the back needs to be bonded, it is recommended to use a single layer structure (2/1)

Film thickness:

From the microscopic point of view, there are many pinholes in the coating, and the size of pinholes is enough to make the external corrosive medium (water, oxygen, chloride ions, etc.) penetrate into the matrix, and produce filamentous corrosion phenomenon under certain relative humidity. The thicker the coating, the fewer pinholes, the better the corrosion resistance of the substrate. As shown in the figure, the influence of different coating thickness on corrosion resistance, the test results show that the coating thickness is more than 20μm, its anticorrosion effect is relatively stable.

Coating protection:

Coating quality and processing also affect the final corrosion resistance of color coating products. If the light is made of cold rolling base plate (not including plating) directly to MCL, due to the corrosion products of iron loose easy absorption of moisture, and no secondary protection, so its corrosion speed quickly, if a fairly thickness of galvanized zinc (aluminum plating zinc/aluminum magnesium) substrate, it can play the role of "firewall", will greatly improve the corrosion resistance of products.