Special Ink Injects Life Color into Prints (Part 2)

Spot inks meet Hong Kong demand

The main business of Chuangyi is spot ink production and production. They offer Pantone spot color inks in two categories. One is a cheap Korean ink, and the other is a US ink with a higher density of 10 to 20 and a relatively high price. Mr. Xie explained: If the density of ink is high, even if it is printed thin at the time of printing, it can meet the requirement of color, and there will be no crisis of color inconsistency. Take the United States spot color ink as an example, even if mixed with transparent ink, varnish, etc., it will not dilute the original color of the ink. Low density inks have this drawback. The printer may try to increase the amount of ink to solve the problem of misalignment, but this will only lead to a series of other problems in the printing press.

For the needs of the Hong Kong printing factory, the spot color ink formulated by Chuangyi completely follows Pantone's color and is not inferior to silk. There are a number of companies that sell spot inks around the world, but it is not easy to find a set that meets the requirements of Hong Kong printing companies.

One of the spot color inks produced by Chuanghan is a film ink designed for film printing. Offset ink printing film is very difficult, there will be scratch, can not dry, easy to fall off and other phenomena, but this special ink ruled out the above difficulties. However, it does not apply to all films. For example, printed PVC and PET have no problem, but PP, PE and other materials need to be tested.

Printing UV inks is quite difficult for most printers. Printing ordinary ink, infrared drying, air drying and other methods, has been able to make the ink dry, but UV printing will use UV light drying, India also requires a completely different technology and printing. Some printing masters have been in business for more than 30 years, and one printing UV has also surrendered in real time. Some of them are even more unsuccessful during the printing years, and they simply do not print. Instead, they use ordinary ink to print films. Many printers also hope to try to modify the printing press UV, but it is not successful. There are also printers that have printed UV inks on the market. However, there are also difficulties in printing. Basically, I have been in the market for so long and I have never encountered an example where a newly purchased UV printer can successfully print on the ink. The general problem they face is that the ink is difficult to dry. In theory, the ink will dry as soon as it is illuminated, but in reality it is not so simple. The problem involves the entire printing technology and takes a long time to explain. Therefore, we sell inks to customers and provide after-sales services to explain to customers the correct methods of use. In particular, anti-counterfeiting inks require more attention and customers need stronger support.

Printing labels are a special product in the screen printing industry and are mainly used for social circulation. Such as banknotes, stamps, and various bonds, promissory notes and other commercial tickets.

Under market economy conditions, the quality of ticket printing and the prevalence of ticket use represent the level of market economy development. In general, all kinds of ticket printing are classified into valuable tickets and general tickets according to different purposes; they are divided into bank tickets, postal tickets, business forms, electromagnetic tickets, etc. according to the application fields and the use forms.

The development of economy and technology puts high demands on ticket security, and the anti-counterfeiting technology is also more complicated. There are design aspects, as well as paper, ink, and printing processes. In the anti-counterfeiting technology of ticket printing, in order to reduce costs, it is necessary to make full use of the advantages of the current printing industry, generally considering starting with anti-counterfeiting inks. In addition to the normal expression of the corresponding hue, various anti-counterfeiting inks also undergo special changes under the influence of external light, heat, reagents or magnetic fields as a means of identification.

The application of ink technology to anti-counterfeiting is achieved by changing the ink formulation or adding special sensitive materials such as photosensitive materials, heat-sensitive materials, magnetic materials, etc. to the ink. Ink anti-counterfeiting technology is currently the most rapidly developing high-tech. Since it is difficult to develop such an ink, the price of imported products is high and it is difficult to buy on the market, which enhances the security of printing. Anti-counterfeiting inks are used in the same way as ordinary inks and are suitable for various printing machines. So versatility is good.

The following are some of the security inks mainly used by our factory for printing tickets.

First, light change ink

Photo-variable ink is a high-tech product that is simple in principle and difficult to manufacture. It uses an optically variable thin film interference filter with varying coating colors as the viewing angle changes to selectively absorb and reflect natural light (multicolor light) for anti-counterfeiting purposes.

The chemical structure of a substance changes when irradiated with a certain wavelength. The absorption spectrum of visible light changes so that a color change occurs. Then, the original color will be restored or not restored under the influence of the irradiation or heat of the light of another different wavelength. We call this phenomenon of reversible or irreversible coloration and achromatism photochromism.

Interference type optical variable ink is the most complicated one in modern anti-counterfeiting inks, and it is a popular high-tech product at present. Optically variable inks are reflective inks with a pearlescent and metallic effect. Color copying machines and electronic copying machines cannot be copied. In products printed with light-variable inks, the ink patches appear as a pair of colors. Such as magenta-blue, green-blue, blue-green and so on. If the pattern is tilted to 60°, the pattern can be shifted from one color to another. Since only the ink film on the print product is thick, a significant color drift phenomenon can occur, so the printing feature is that any other ink and printing method cannot be imitated.


The anti-falsification of light-variable ink is specifically reflected in:

(1) The difficulty in the manufacture of light-variable ink is mainly due to the difficulty in controlling the thickness of each layer of the thin-film interference filter. Generally, a multilayer high-refractive-index dielectric film is used to solve the problem.

(2) The film transfer and stripping technology is also relatively difficult. The multilayered composite film is placed in a preselected solvent, and the multilayer composite film is peeled off to form fine fragments. The ratio of the top and bottom surface area to its side area is at least 3:1, and then vacuum dried to make a photochromic material. This multi-layered film fragment selectively absorbs a portion of the light wave and reflects the remaining light wave to appear color. The optically variable inks can be produced by adding these multi-layered film fragments to specially designed binders and adding transparent dyes and other fillers. In addition, the connecting department and the solvent section used in this ink are special. Because it must align each of the inks printed on the substrate in parallel and float on the surface of the connecting material.

Second, fluorescent ink

Fluorescent ink is one of the inks used by our factory for printing tickets. Its main component is fluorescent pigments. Fluorescent pigments are functional light-emitting pigments. The difference from ordinary pigments is that they can absorb certain forms of energy when exposed to external light (including ultraviolet light), excite photons, and release absorbed energy in low visible light, resulting in different Hue fluorescence. Different shades of light combine to form an unusually bright color, and when the light stops irradiating, the luminescence phenomenon disappears, so it is called a fluorescent pigment. The ratio of fluorescent pigments to macromolecular resin binders, solvents and auxiliaries can be obtained by grinding the fluorescent ink. This type of ink, which is invisible to the naked eye, only emits light under ultraviolet light or infrared light. Due to its switchable and hidden characteristics and its inability to accurately reproduce on a color copying machine, the ink is used in the special printing industry. The application is becoming more and more popular.

Fluorescent inks are suitable for printing on paper and vinyl films, and fluorescent inks can be used for screen printing and gravure printing. The rheological properties of most fluorescent inks are pseudo-plastic flow, and the viscosity is small. This characteristic determines that the printing process is very different from that of common inks.

The inorganic fluorescent substance emits light from the crystal. If the pressure is too high, the crystal may be broken, so that the brightness of the light is reduced. Therefore, relief printing is generally not used. When performing gravure printing and screen printing, besides paying attention to the characteristics of stickiness, connection materials, and drying properties, it is also necessary to pay attention to the adjustment of the printing pressure, and it is not possible to make the printing pressure too large to affect the printing effect.

Third, thermal ink (color change ink)

Thermal inks are specialty inks that change color with temperature. That is different colors show different colors, also known as temperature-induced color change ink.

1. Development of Thermal Ink

Because the thermal ink is a kind of special ink that can change the color of the pigment with the temperature change, that is, different colors show different colors. The color change of the ink caused by heat mainly depends on the color changing pigments, because the color change before and after the heating of these pigments is very different, and as a basis for determining whether the ticket is forged. We know that there are many varieties of pigments that undergo color changes due to heat. However, the pigment as a thermal ink must have the following conditions: be sensitive to heat, have a fixed color at room temperature, and change rapidly when reaching a predetermined temperature, there is a clear color limit, that is, the temperature range of color change is narrow, The color difference before and after discoloration should be large, affected by the external environment to a small extent, and the performance is stable under light and humid weather conditions without decomposition or fading.

The filler is present in the thermal ink as an auxiliary material. Some fillers can make the ink film bright, stable, and uniform in color. Adjusting the discoloration temperature of the color pigment can improve the adhesion of the ink layer. In addition, the variety and amount of fillers affect the discoloration of thermo-sensitive inks. The reason is that under the effect of temperature, certain activating elements can play a catalytic or inhibitory role on color-changing pigments, resulting in increased temperature of discoloration or The effect of this reduction should be examined when manufacturing thermal inks. The binder is also an important component of the thermal ink. It requires good temperature resistance, strong adhesion, light color, and should not react chemically with the pigment components. The type and amount of the resin have different effects on the temperature of the color display. Therefore, the connection section of the temperature-sensitive ink should be selected according to the ink's overall performance.

2. Thermal ink printing suitability

Thermal inks are commonly used for screen printing and gravure printing. Screen printing is required for substrates that require a warm discoloration. Especially suitable for large batches, but the street has some special bead-shaped substrates. In addition, attention should be paid to the relationship between the thickness of the ink layer and the effect of temperature-sensitive color change. At the same time, the viscosity, volatility, and the like of the ink must also be considered because these characteristics affect the printing process and influence the color rendering effect. Be careful when printing and drying. It is best not to heat. The heating should be moderate so that the discoloration properties are not destroyed and cannot be restored.

Source: Wanke Online