According to the resin classification, the coatings are oily, phenolic, epoxy, polyester, vinyl, acrylic, amino, etc. According to the purpose, there are internal coatings, external coatings, color coatings, varnish coatings, special coatings, etc. tinplate printing ink is different from limb printing ink. It must have the characteristics of heat resistance, processability, drying property, high temperature sterilization resistance and transparency.
The coating is determined according to the product. For example, for ham tin printing, aluminum powder coating with excellent 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 edge during processing. Need to use transparent golden yellow coating , the purpose is to prevent rust and keep 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, and tasteless, and meet the food hygiene and safety requirements. In addition, it should also conform to 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 without fading or losing gloss.