Auxiliary materials include the two aspects that must be applied when manufacturing the binder and the application after the ink is made. The purpose is to adjust the printability and dryness of the ink and improve the printing effect.
Filler is a white transparent or opaque substance. It is mainly used as a filler for pigments. It can not only reduce the amount of pigment, reduce the cost of ink, but also adjust the fluidity of the ink. It can also increase the thickness of the ink film and improve its wear resistance. , But it has no tinting power and hiding power. The filler is selected according to the coloring agent, mainly including barium sulfate, talc, kaolin, calcium carbonate, aluminum hydroxide, etc., which are pulverized into white powder when used.
The function of the thinner is to reduce the viscosity of the ink, prevent film peeling, and make the ink workable. Commonly used diluents are oligomeric imidine oil, mineral oil and so on. The former is easy to mix with ink and has a soft effect; the latter has obvious dilution effect, but avoid excessive use, otherwise the printing effect will not be good.
The function of the diluent is to dilute the color of the ink. The light-colored ink is formulated with diluting agent as the main and dark-colored ink as a supplement. Attention should be paid to the effect of diluting agent performance. Appropriate diluting agent should be selected according to the requirements of color sample transparency and product use. There are three common types of thinners: white ink, transparent oil, and gloss paste. White ink has poor transparency and strong opacity, and the blended light-colored ink has a powdery texture. It is often used for the blending of light-colored inks for field printing. Transparent oil, also known as Weili oil, is the earliest thinner used in offset printing inks. Transparent oil is a light yellow transparent oil agent, mixed with some inks, such as golden red, light blue, etc., will darken the color, and also have the effect of inhibiting drying, so it is only used for the preparation of light-colored inks that are generally required. The blending of fine products light-colored ink generally uses bright paste. The gloss paste is a resin-based diluent that is almost colorless and transparent. It has good compatibility and has little effect on the color of the colored ink. It also has the characteristics of strong water resistance, fast drying, and good conjunctival brightness. It is currently the most ideal Of diluent.
The function of the anti-skinning agent is to inhibit the drying speed of the ink and prevent the ink from drying and conjunctivating mechanically. The main components of the anti-skinning agent are organic reducing agents and antioxidants, which can be added to the ink or sprinkled on the machine in contact with the ink.
The function of the anti-reverse printing agent is to prevent the printing ink layer from being reversed to the back of the paper to ensure the printing quality. The most commonly used anti-offset agent is corn starch.
The function of the slip agent is to improve the friction resistance and fluidity of the ink, reduce the viscosity, improve the smoothness of the film, and reduce the phenomenon of paper fuzzing. Commonly used slip agents in inks include high melting point microcrystalline wax and synthetic wax.
There are many other additives, such as dispersing agents, wetting agents, desiccants, stabilizers and so on.