Classification of ink

Photochromic ink

Photochromic inks, also called photochromic inks, are photochromic or photoactive compounds that are added to the ink. In the sun, the ink can change from colorless to colored, or from orange to black, etc., and can generally be divided into common type and UV type. . Ordinary type means that under the effect of ordinary daylight and strong light, the color of the ink will change, and it will return to its original shape after leaving the light source. It looks like it is discolored under the sun, and it is essentially changed by ultraviolet radiation. The color changing wavelength is 400~800nm. The application of this kind of ink in packaging and decoration not only can improve the grade of goods, increase interest, but also highlight the anti-counterfeiting effect. UV type ink is colorless or does not change color under the irradiation of ordinary light sources, but it will show bright red, orange, yellow, green and green fluorescence under UV light (UV light) irradiation. Most large denomination banknotes are printed using this kind of ink, and authenticity can be revealed under the effect of a counterfeit money detector.

In screen printing, thermochromic and photochromic inks can be transferred to different substrates, such as paper, cloth, nylon, plastic, metal, glass, ceramics, etc., by screen printing. It has the characteristics of sensitive to external conditions, obvious changes and rapid recovery. It is the ideal material for anti-counterfeiting technology and interesting gifts. It has broad development and application value.

Fluorescent ink

The fluorescent ink is made of a fluorescent material dissolved in the corresponding resin. Fluorescent pigments are generally coarser particles, and the types of binders are also more. Different binders will produce different fluorescence. When using fluorescent inks, it should be ensured that it has sufficient concentration, and the ink layer on the prints is a little thicker. Satisfactory fluorescence effect is guaranteed. Fluorescent inks are printed brightly after screen printing, and the decorating effect is very good. Under the action of visible light and ultraviolet rays, it can give off glittering fluorescence. Fluorescent ink can be self-aligned, different formulations can get different fluorescence effects, and its anti-counterfeiting effect is better. However, fluorescent inks have poor light resistance, and prints used outdoors are not effective.

Storage and Phosphorescent Inks

The light-storing pigments are prepared using certain zinc sulfide/copper phosphors, calcium sulfide/germanium phosphors, etc. having a phosphorescent effect in inorganic phosphors. Inorganic fluorescent substances are generated by crystals. If the crystals are broken due to pressurization, resulting in reduced luminosity, screen printing is generally suitable. Ink carriers and fluorescent substances are mixed during use. Phosphorescent inks are characterized by the ability to absorb light and emit light at a certain wavelength within a certain period of time. The pigment of this ink is a zinc sulfide containing a small amount of impurities (such as cadmium zinc sulfide), which is afraid of acid and alkali, and therefore requires neutral resins such as cyclohexanone resin, cellulose ester and ether. In addition, heavy metals, desiccants, and drying oils should not be added to the ink to avoid damaging the pigment material. The link material used requires transparency and UV light transmission. This type of ink is mainly used for printing advertisements, signage, etc. However, if phosphorescent inks and fluorescent inks are used in anti-counterfeit packaging printing, they can receive very good packaging decoration and anti-counterfeiting effects.

Printing ink

The printing ink is mainly composed of pigments, fillers, binders, etc. The choice of pigments is an important step in determining the hue and vividness of printed products. Many manufacturers and ink manufacturers have customized special inks for printing of each product. Its formula is kept confidential by the ink factory. For example, the “China” and “Peony” cigarettes produced by the Shanghai Cigarette Factory are printed with special inks that are specially customized at the Shanghai ink factory. This type of ink does not know that the detailed formula is difficult to tune, and therefore has a better anti-counterfeit effect.

Composite ink

After mixing two or more anti-counterfeit inks in a certain proportion, composite inks with new properties can be developed. If the ink formulations are not fully understood, it will be difficult to imitate them.

Other security screen printing ink

Plastic security ink. Applicable to PP, PVC, PE, PS, ABS, PC and other plastic products, with 150 ~ 200 mesh polyester net, each kilogram of ink can be printed 20 ~ 30m. , Dry naturally or at 130 °C for 3 minutes.

Metal, glass, ceramic security ink. Suitable for printing on metal temperature signs, color-changing glass ware, color changing milk cups and ceramic tea sets, etc., with 70 to 100 mesh polyester mesh, 10 to 20 square meters per kilogram of ink, and drying conditions of 25, 48, or 120 degrees Celsius. 45min.

Glass, ceramic decal transfer paper security special ink. Applicable to the printing of glass and ceramic decals, with a 150 to 200 mesh polyester web, and the drying conditions are 200°C and 20 minutes after water transfer.

Water-based security inks and printing pastes. Applicable to printing on paper, cotton, knitted fabrics, T-shirts, sportswear, etc., with 80 ~ 150 mesh polyester net, each kilogram of ink can be printed about 20m2 (cotton fabric will be less than this number), drying conditions for 130 °C, 3min.