Paint on tinplate Steel Sheets before printing. Normally, the front and back sides of the tinplate Steel Sheets need to be printed with the paint on the main surface and the paint on the inner surface to ensure that the printed SPTE products have good canning, canning and appearance decoration requirements. Of course, the coating film thickness of this kind of coating is usually only a few. It is a micrometer thick, it is difficult to completely cover the surface of the tinplate Steel Sheets. Therefore, in order to prevent corrosion at the defects of the organic coating film, the spcc tinplate is required to have corrosion resistance, and the oxide film on its surface provides the coating film density, and the surface oil layer protects the coating film leveling. The coatings are classified into oily, phenolic, epoxy, polyester, vinyl, acrylic, amino, etc. according to the resin. According to the purpose, they are divided into internal coatings, external coatings, color coatings, varnish coatings, special coatings, etc. spcc printing ink is different from limb printing ink. It must have heat resistance, processability, dryness, high temperature resistance, sterilization and transparency.
The paint is determined according to the product. For example, for ham tin printing, aluminum powder paint with good sulfur resistance should be used for internal coating, and epoxy phenolic coating should be selected for general anti-rust. The external coating should be decided according to the pattern designed by the customer. For example, the metal packaging boxes of candy boxes and moon cake boxes are used to prevent scratches and rust at the curling iron during processing. Need to use transparent golden yellow paint, the purpose is to prevent rust and beautiful. At the same time, the hygienic requirements of the content must be considered when choosing the inner coating. The inner coating must have corrosion resistance, good adhesion, flexibility, non-toxic, tasteless, and meet the food hygiene and safety requirements. In addition, it should also comply with the processability of the can, such as the heat of high-frequency resistance welding, the local high-temperature heating of the internal coating, and the high-pressure cooking after canning.