The main components and auxiliary materials of printing ink

Colors include pigments and dyes. Color can give the ink with different colors and color concentrations, and make the ink have a certain viscosity and dryness, commonly used is azo series, phthalocyanine series pigments.

The bonding material is made of a small amount of natural resin, synthetic resin, cellulose, rubber derivatives, etc., dissolved in drying oil or solvent, it has a certain fluidity, so that the ink forms a uniform thin layer after printing, and forms a certain strength film after drying, and plays a protective role in the pigment, making it difficult to fall off.

The auxiliary material includes two aspects that must be applied when the bonding material is manufactured and the ink is applied after it is made, in order to adjust the printability and dryness of the ink and improve the printing effect.

Filler is a white transparent or opaque substance, mainly used as a pigment filler, which can reduce the amount of pigment, reduce the cost of ink, and adjust the fluidity of ink, etc., but also increase the thickness of the ink film, improve its wear resistance, but it does not have coloring power and hiding power. Depending on the coloring agent, the filler is mainly barium sulfate, talc powder, kaolin, calcium carbonate, aluminum hydroxide, etc., which is ground into white powder when used.

The role of diluent is to reduce the viscosity of the ink, prevent the phenomenon of peeling film, so that the ink has the operational suitability. Commonly used diluents are low polymerized amidine oil, mineral oil and so on. The former is easy to mix with ink, the effect is soft; The latter dilution effect is obvious, but do not overuse, otherwise the printing effect is not good.

The function of the diluent is to dilute the color of the ink. The preparation of light ink is based on diluent, and dark ink is supplemented. Attention should be paid to the influence of diluent performance, and appropriate diluent should be selected according to the requirements of color sample transparency and product use. Diluent commonly used types are white ink, transparent oil, light paste three. The white ink has poor transparency, strong hiding ability, and the light ink formulated has a powder texture, which is often used for the preparation of light ink for field printing. Transparent oil, also known as Willy oil, is the earliest used offset printing ink diluent. Transparent oil is light yellow transparent oil agent, mixed with some inks such as golden red, light blue, etc., will make the color dark, but also has the effect of inhibiting drying, so it is only used for the general requirements of light ink preparation. The preparation of fine products light ink generally uses bright paste. Bright paste is almost colorless transparent resin type diluent, has good compatibility, has little influence on color ink color, but also has strong water resistance, drying faster, conjunctiva bright characteristics, is currently the most ideal diluent.

The function of the anti-skinning agent is to inhibit the drying speed of the ink and prevent the ink from drying the conjunctiva 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 machinery in contact with the ink.

The role of the anti-reverse printing agent is to prevent the printing ink layer from printing on the back of the paper to ensure the printing quality. The most commonly used anti-printing 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 finish of the film, and reduce the phenomenon of paper hair. The commonly used slip enhancers in inks are microcrystalline wax with high melting point and synthetic wax.

There are many other additives, such as dispersant, wetting agent, desiccant, stabilizer and so on.