The basic composition and characteristics of ink


The ink consists of pigments, binders, fillers, and additives.

(1) Pigments

Pigments play a colorizing role in the ink, which in turn has a direct effect on some properties of the ink.

The pigment is a color, black or white highly disperse powder that is insoluble in water and organic solvents. According to its source and chemical composition, it is divided into organic pigments and inorganic pigments.

1 Inorganic pigments are oxides of non-ferrous metals, or some metal-insoluble metal salts. Inorganic pigments are further divided into natural inorganic pigments and artificial inorganic pigments. Natural inorganic pigments are mineral pigments.

2 Organic pigments are colored organic compounds and are also divided into natural and synthetic categories. Nowadays, synthetic organic pigments are commonly used. There are many varieties of organic pigments, and the colors are relatively complete. The performance is superior to that of inorganic pigments.

Dyes are organic compounds which are soluble in water and sometimes also dissolved in organic solvents. Insoluble color precipitates, called lake pigments, can be prepared from certain dyes for the production of printing inks.

The requirements for the pigments used in printing inks are quite high, especially the color, dispersion, light resistance, transparency, etc., and the hue of color pigments is required to be close to the spectral color, the saturation should be as large as possible, and the magenta, cyan, and yellow colors used for the three primary color inks should be used. The transparency of the pigment must be high. All the pigments should not only be water-resistant, but also should be quickly and evenly combined with the binder. The oil-absorbing ability of the pigment should not be too large. The pigment is preferably resistant to alkali, acid, alcohol and resistance.

(2) Connection material

The binder is the main component of the ink, serves to disperse the pigment, imparts proper sticking, fluidity and transfer properties to the ink, and serves to fix the pigment on the surface of the print after filming by printing. The connecting material is commonly known as varnish.

The binder can be made of various materials, such as various dry vegetable oils, most of which can be used to make binders for inks, mineral oils can also be made into binders, solvents and water, and various synthetic resins can be used to make them. The binder.

The rheology, viscosity, neutrality, acid value, color, water resistance, and printing performance of the ink are mainly determined by the binder. The same pigment, using different binders, can be used to make different types of inks; Use different colors. The ink produced is still the same type of ink, because it can not change the fundamental performance of the ink, so the quality of the ink is good or bad, but depends on the pigment, but mainly depends on the connection material.
(3) Packing

The filler is a white, transparent, translucent or unpleasant powder substance. Mainly from the filling, filling the pigment part, the appropriate use of some filler, can reduce the amount of pigment, reduce costs, but also can adjust the properties of the ink, such as thick, fluidity, etc., but also improve the flexibility of formula design.

(4) Additives

Additives are some of the materials added to improve the performance of the ink itself during the manufacture of the ink, as well as during printing. The inks formulated according to the basic composition still cannot satisfy the requirements in certain characteristics, or they must be added with a small amount of auxiliary materials when they cannot meet the requirements for printing use due to changes in conditions.

There are many additives, such as: desiccant, desiccant, thinner, remover, plasticizer, etc.

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.

5. 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.

6. 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.

7. 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.

8. 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.

9. 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.