The first material required for tinplate yellowing and whitening is paint. Under normal circumstances, the tinplate front and back sides need to be printed on the main surface and the inner surface to ensure that the printed tinplate products have good requirements for canning, and appearance decoration. Of course, the thickness of this printed film is usually only a few microns thick, and it is difficult to completely cover the tinplate surface. Therefore, in order to prevent the corrosion phenomenon at the defects of the organic coating film, tinplate is required to have corrosion resistance, the oxide film on the surface thereof provides coating film compactness, and the surface oil layer protects the coating film leveling property.
Coatings are classified as oily, phenolic, epoxy, polyester, ethylene, acrylic, amino, etc. by resin, and are divided into inner coating, outer coating, color coating, overcoat coating, special coating, etc. according to use. Different from limb printing inks, tinplate printing inks must have heat resistance, processability, dryness, high temperature sterilization resistance, and transparency.
The coating is determined by the product. For example, ham can-printed tinplate, the inner coating should use aluminum powder coating with good sulfur resistance, and general antirust can choose epoxy phenolic coating. The outer coating needs to be determined according to the customer's design.