What is metallic ink?

Before talking about metallic ink, explain what ink is? Ink is an important material for printing and is inseparable from the printing process. It displays patterns and text on the substrate through printing. The main difference between ink and paint is that the ink is relatively thick and the paint is relatively thin; the ink is finer than the paint, and the decorative effect is more demanding; the construction method of the ink is different from that of the paint, and the ink is mainly used for printing, such as gravure and embossing. , Silk screen, offset printing, etc.

 

Metallic inks refer to inks formulated with metallic pigments, which have metallic luster. Generally speaking, gold ink and silver ink are such inks. The pigments of metallic inks are mainly gold powder and silver powder (copper gold powder and aluminum pigment), and other pigments can also be added to produce inks with special colors, which are called colored metallic inks. When the binder is acidic, the copper-gold powder reacts with a small amount of sulfur, and it is easy to turn black; after printing, it will gradually lose its luster when it interacts with the sulfur in the atmosphere. Therefore, gold ink can also use aluminum pigments and dyes as pigments, but the gloss is slightly worse.

 

The binder of metal ink generally uses resin with extremely low acid value and amine value, so as not to affect the gloss of the ink, such as ethyl cellulose, nitrocellulose, polyvinyl acetate, ketone resin, polyphthalamide resin, and add some wax To improve the suspended state of pigments. Metallic inks can also be formulated to be solvent-based, but they are often used on-the-spot due to their low sluggishness. The polarity of the solvent does not need to be too large, otherwise the pigment will easily precipitate due to excessive wetting. Xylene, isopropanol solvents, etc. can all be used as solvents for metallic inks.

 

Leafing aluminum pigment

Aluminum pigments use saturated fatty acids such as stearic acid as lubricants in the ball milling stage. Stearic acid is adsorbed on the surface of the aluminum flakes to make the aluminum flakes hydrophobic and oleophobic. When applied to the ink system, the aluminum flakes coated with stearic acid cannot be infiltrated by the base material, and the density is relatively small, which reduces the downward gravity of the aluminum flakes. On the other hand, with the upward thrust of the molecules moving to the surface of the carrier when the solvent volatilizes, the sinking force caused by the weight of the aluminum flakes is offset to make the aluminum flakes float to the surface of the carrier and oriented to form an opaque silver film near the surface of the paint film. As the aluminum sheet floats on the surface of the paint film, a dense film is formed, which isolates the air from contacting the resin and the substrate, thereby providing a good physical shielding effect. At the same time, the ink uses high-grade leafing aluminum pigments to enhance the color rendering effect. , So the ink with leafing aluminum pigment also has a very good decorative effect.

 

Non-leafing aluminum pigment

The aluminum pigment uses unsaturated fatty acid (oleic acid or erucic acid) as the aluminum flake coating material in the ball milling stage to make the aluminum flakes have lipophilic and hydrophobic properties, so the aluminum flakes can be completely wetted by oily solvents and resin systems and evenly distributed throughout the entire In the paint film, there is a tendency to sink, so the adhesion is very good, the film is firm and stable, and it can be recoated and polished. Compared with leafing aluminum paste, non-leafing aluminum paste can provide a more significant improvement in surface properties and has a very good decorative effect. It is widely used in various occasions such as vehicles, furniture, electronic products, and coils. Automobile paint, motorcycle paint, bicycle paint, plastic paint, architectural paint, ink, mobile phone shell and button, electromechanical shell coating and many other fields.

 

Application of aluminum pigments in metallic inks

The ink made from aluminum pigments is called metallic ink. As a new type of printing material, metallic ink has expanded the creative space of the packaging industry and opened up new ideas for the packaging industry. It is widely used in packaging, food packaging, daily chemical product labeling, and flexible packaging.