As tinplate sheets products are usually printed first, and then tin plate cans are made, the tin plate steel cans need to undergo bending, stretching, welding, flanging, rolling and other processes. In addition to requiring a dry coating film and ink layer with sufficient strength, Sufficient adhesion is required to avoid deformation, cracking, and even peeling of tin plate steel during the forming process. Because the adhesion between ink and tinplate sheets is not ideal, it needs to be in between. Apply a layer of paint (ie,tinplate sheets coating with base oil) to improve adhesion.
base oil generally include vinyls, modified vinyls, and epoxy-amino groups. The requirements for the performance of the base oil are as follows:
1) The base oil transparency should be good, and the yellowness after drying to form a film is small, and the metal texture cannot be covered.
2).The tinplate sheets coating base oil has good leveling, thermosetting and flexibility.
3). The tin plate steel coating base oil has sufficient affinity for ink and good adhesion to various types of iron sheet.
Since the tinplate sheets coating base oil is mostly a low-molecular compound, after drying and forming a film, it is susceptible to additives in other coatings covering it, reducing its physical and chemical properties (adhesion, yellowing), so base oil must be matched with varnish.