Base oils are generally vinyls, modified vinyls, epoxy-aminos, and have the following requirements for base oil properties:
1. Better transparency, less yellowing after drying and filming, cannot cover metal texture.
2, good leveling, heat curing and flexibility.
3, the ink has enough affinity for all kinds of iron skin has good adhesion.
Because the bottom oil is mostly a low-molecular compound, after being dried and formed into a film, it is easily affected by additives in other coatings that are covered on him, and its physical and chemical properties (adhesion, yellowing) are reduced, so it is necessary to match with the varnish.
The main components of white cocoa are: film-forming substances, pigments, driers, auxiliary materials, and solvents. Film-forming substances are mainly oils and resins, pigments and inks are similar, auxiliary materials are added with anti-rust pigments, and solvents are carriers. In order to obtain a good printing effect, the colors of white cocoa can be blended with different pigments as needed.
According to the layout design requirements, whitening can sometimes not be used, and printing can be used instead. Compared with white printing, white coating has the following advantages:
1, white coating can be coated, the oven baking several times is not easy to yellow.
2, because white coating can be thicker than white ink 3-4 times thicker than white ink has good whiteness and fullness, and smooth, there is enough luster.
3, because white can be in the filming material is usually a polymer, resistant to a variety of varnish oil etching.
According to different film-forming materials, white cocoa can be made of acrylics and polyesters. Polyesters have good bending properties and can be directly used in various can bodies. Acrylics are used for high temperature cooking and are used in food cans and other foods that require high temperature cooking. product.