2. White (white ink) or white (white porcelain)
(1). Printed white. It has iron permeability and can see metal lines. Since the tinplate products are generally printed first, and then cans, the cans are subjected to bending, stretching, welding, flanging, winding, etc., in addition to requiring sufficient dry film and ink layer to have sufficient strength, It is required to have sufficient adhesion to avoid deformation of the coating film and ink layer during the forming process, cracking, or even peeling off from the tinplate. Since the adhesion between the ink and the tinplate is not ideal, it is necessary to A layer of paint (ie, base oil) is printed, which is a white background process to improve adhesion. The white ink requirements are as follows:
① The transparency is better. After drying, the yellowing property is small, and the metal texture cannot be covered.
② Has good leveling, heat curing and flexibility;
③ Has sufficient affinity for the ink, and has good adhesion to all kinds of iron.
(2). Apply white. White is relatively impermeable to white. Make the pattern clearer, brighter and fuller. The commonly used raw material for white coating is white diced, which has the following advantages:
①. It is not easy to yellow when baking in the drying room.
②. Because the whiteness is 3-4 times thicker than the white ink, it has good whiteness and fullness compared with white ink, and it is smooth and smooth enough.
3. Because of the white butyl, the film-forming material is usually a polymer, which is resistant to various varnishes.