Section IV Anti-counterfeiting ink

The so-called anti-counterfeiting ink is a special printing ink that is made by adding a special performance anti-counterfeiting material to the ink binder and processed by a special process. The anti-counterfeiting function of the anti-counterfeiting ink is realized by an internal mechanism, and the anti-counterfeit is realized by means of a printing technology method. Due to the different characteristics of various products and printed matter, the method of printing ink on its surface (article or surface) is different. Different inks must have different capabilities. The same printing method can be achieved with different inks. Completely different security effects, this is the key to security ink.
The mechanism of the anti-counterfeiting ink is realized on the basis of ordinary ink, that is, during the processing of the ordinary ink, its components and processes are changed, so that it has different characteristics from ordinary ink. Anti-counterfeit inks have a special component added to the ink, so that the printed product has an anti-counterfeiting effect. Under certain conditions, the physical and chemical properties of the printed surface are changed by the effects of light, heat, force, reagents, magnetism, and electricity (eg, discoloration, special colors, special light, heat generation, electrical signals, or magnetic signals) Wait). When certain conditions are eliminated, they immediately recover or lose their original state and performance (quality), and some of them can repeat the original state.
According to the anti-counterfeiting function achieved by the product, the following types of anti-counterfeiting inks can be used.

First, anti-counterfeit ink type 1. UV fluorescent ink UV fluorescent ink refers to ultraviolet light (200-400nm) irradiation, can emit visible light (400-800nm) special ink. According to the different wavelength of the excitation light source, it can be divided into short-wave ultraviolet excitation fluorescence anti-forgery printing ink (excitation wavelength of 254nm) and long-wave ultraviolet excitation fluorescence anti-forgery printing ink (excitation wavelength of 365nm). According to whether the color of the ink is divided into two kinds of colored fluorescent ink and colorless fluorescent ink. The fluorescent material suitable for the security ink is mainly a chemically synthesized rare earth organic complex. Conventional organic rare earth fluorescent complexes have the characteristics of simple preparation, easy dispersion, dissolution and refinement in oily media. They are colorless under visible light and exhibit strong fluorescence under ultraviolet light excitation. Such as tristyryl derivatives, vinyl naphthalene ethylene derivatives, tetraphenylene triene derivatives and other organic fluorescent compounds, suitable for the production of such inks. For details on fluorescent inks, see Section 2 of this chapter.
2. Thermal security ink (thermochromic security ink)
Under heating conditions, the ink that can produce discoloration effect is a heat-sensitive anti-counterfeiting ink. According to the different temperature required for discoloration, can be divided into hand-temperature color anti-counterfeiting ink and high-temperature anti-counterfeiting ink. The hand-type color-changing anti-counterfeiting ink refers to an ink that can change color at a temperature of 34-36° C., and the high-temperature color-change proof ink refers to an ink that can undergo a discoloration effect at a temperature of 40-100° C. or higher. According to the discoloration method, it can be divided into single color reversible, multi-color reversible, single color irreversible and multi-color irreversible thermal ink. Thermochromic substances can be classified into inorganic salts, coordination compounds, organic substances (dye molecules) and liquid crystal polymers. The principle of color change of thermochromic substances can be found in the second part of the thermal ink and liquid crystal ink in the third section of this chapter.
There are many substances that can generate thermochromic substances, but they are truly suitable for the production of thermochromic security inks. The following conditions must be met:
1 The color change sensitivity is high and it shows a sharp color change in a short time: the color contrast is large before and after, such as red to blue, blue to white, and yellow to blue.
2 appropriate color temperature. The discoloration temperature should be controlled between 40-100 °C.
3 good stability. Under the influence of temperature, humidity, light, etc. under different climatic conditions, sensitive and effective during the use period should be guaranteed.
3. Sunlight-induced color-changing anti-counterfeit inks From the surface, this ink is discolored due to the action of sunlight, and it is also substantially discolored by ultraviolet radiation. Daylight-induced color-changing inks can change from colorless to violet, blue, yellow, etc. in sunlight (also under UV light), and can also be changed from one color to another. The principle of color change is that when sunlight or ultraviolet (UV) light is irradiated onto the security ink, the photosensitive material in the ink is excited, and its molecular structure changes, resulting in a change in appearance color. When the external stimulus (sunlight or ultraviolet light) is moved, the photosensitive material molecules in the ink return to the original ground state, and the ink returns to its original color.
4. Intelligent anti-counterfeit ink BY97 smart anti-counterfeiting ink, intelligent anti-counterfeiting ink, and intelligent anti-counterfeiting identification instrument have been developed recently in China. They are high-tech products that utilize a new spectrum analysis technology and computer technology. Users can print smart anti-counterfeit labels using the provided special compounds and intelligent counterfeit identification devices.
Intelligent anti-counterfeiting technology is mainly manifested in the variability of anti-counterfeit materials (anti-counterfeiting inks, glues, etc.). The anti-counterfeiting material is composed of a variety of variable chemical substances. The nature, type, quantity, content, and existing form of the characteristic compound determine the particularity and individuality of the anti-counterfeiting material. According to this particularity, individual production of anti-counterfeiting materials and manufacturing inspection instruments (which can be given after computer processing), it is called smart anti-fake material and intelligent anti-counterfeiting discriminator.
The technology uses many materials, many production equipment, large investment, complex processing technology, difficulty, and high technical content. When testing, results can be seen directly from the computer screen. Due to the use of computer identification, the variability is extremely strong. Each authentication terminal has an anti-counterfeiting product and the machine's encryption code. Only when it knows the identity of the seized mark or the seal code at the same time, can it be identified using a dedicated detection instrument.
5. Magnetic anti-counterfeiting ink Magnetic ink is made by adding magnetic material to the ink. With this ink printed pattern or logo, magnetic signals can be detected with a magnetic detector. With its printed password and other information can be read out by the decoder.
Magnetic ink is used for anti-counterfeiting packaging inks. It is mainly printed on a certain part of the package with magnetic ink, and can be detected by special means to form a password anti-counterfeit. In addition, various magnetic cards are subject to reading system friction during scanning and reading, and must be stored under the effect of the electric field of the reading system. Therefore, it is required to obtain sufficient ink layer thickness and density during printing. For details, see the chapter. The content of one section.
Magnetic materials are easily available, and the magnetic ink is printed on the product and is susceptible to external friction and the like, so that the magnetic properties are reduced or even disappeared, thereby affecting its anti-counterfeiting effect. It has been reported that anti-counterfeiting inks that have been developed after being excited by electromagnetic waves have been successfully developed in China.
Japan has applied magnetic ink to print yen, but where and how much ink is used is absolutely confidential. According to relevant experts' tests, the Japanese yen banknote with a denomination of 10,000 yuan has magnetic ink in the 6.25 square meters of the upper right corner. The ink can detect as many as 14 elements, and the magnetic metals are iron, cobalt, and nickel. The highest iron content, cobalt, nickel content is minimal. The main components of magnetic inks are cobalt doped iron oxide and iron oxide. Paper magnetic field strength is 11×10-4N/(A·m).
6. Fluorescent inks and phosphorescent inks Fluorescent inks are made by dissolving fluorescent materials in the corresponding resins. The fluorescent pigment particles are generally coarse, and the types of binders are also many. Different binders produce different fluorescence. In the second section of this chapter, the specific principles of the fluorescent ink and its printing characteristics are described.
In the use of fluorescent ink should be maintained at a sufficient concentration, the ink layer on the print should be a bit thicker, so as to ensure a satisfactory fluorescence effect. Prints printed with fluorescent inks are brightly colored and have a good decorating effect. Under the action of visible light and ultraviolet rays, they can produce glittering fluorescence. The anti-counterfeiting packaging fluorescent inks have the best anti-counterfeiting effect. Different formulas can get different fluorescence effects, and it is generally difficult to make realistic imitations. Formulas are in the hands of the enterprises themselves, thus forming anti-counterfeit recipes. Fluorescent inks have poor light fastness, and the results for outdoor prints are not good.
Phosphorescent inks are characterized by light that can be absorbed into them and emitted at a certain wavelength for a certain period of time. Its pigment is zinc sulfide.
Blending phosphorescent inks with fluorescent inks can result in better anti-counterfeit packaging.
7. Anti-cracking inks are used to print the shading of securities such as cheques to prevent alteration and forgery. Also known as security inks, insurance inks, and security inks. Anti-printing inks should also fade or change color when pens are changed by chemicals such as discoloration. Therefore, dyes (such as certain basic dyes and alcohol-soluble dyes) that can fade with acids, bases, and oxidants are used as the colorants. Or use colorless agents (such as diphenyl hydrazine, diphenol, thiazolium, etc.) that can be discolored, such as colorless but discolored spirits, to achieve the purpose.
Instead of drying the conjunctiva, the safety ink is used as a binder, but water or alcohol is used as the binder for the ink to ensure that the pigment fully reacts with the discoloration and is easily damaged by rubbing. Therefore, the binder of the ink is mostly made of gum, dextrin, glycocalyx, ethyl cellulose, etc., and the pigment is adhered to the surface of the paper. Some surfactants (such as triethanolamine oleate), manganese sulfate, etc. can also be added to the ink, which will oxidize and color after rubbing. There are also oil-soluble dyes that are dissolved in the osmotic drying ink. After the printing, the color material penetrates into the deep part of the paper, and the purpose of anti-counterfeiting can also be achieved. Printed materials that are printed with fluorescent whitening dyes or fluorescent pigments emit light under ultraviolet irradiation, but there is also some kind. The degree of security effects. The ink binders are water, alcohol, glycerin, Turkish red oil, and the like.
Therefore, the cheques written in the ink and the invoices, etc., will change color or appear to be "waste" if they encounter a correction fluid.
8. Epoxy anti-counterfeiting ink is added to the ink by adding special chemical reagents or microcapsules containing color-changing substances. Colored or invisible graphics printed with this type of ink will undergo color changes (red, blue, black, green, purple, yellow, etc.) when rubbed or pressed with a nail, a hard object, or a tool. According to the user's request, the user can select the color to be no longer faded, and the product is enabled and cannot be pasted on the imitation product.
9. Chemical encryption security ink Add special chemical reagents or other substances in the ink, can print invisible images that are not visible to the naked eye, and display hidden images immediately after applying a corresponding reagent in the circled range during identification. Or produce fluorescence.
10. Anti-counterfeit inks and seals used for ink seals and inks are also an ink, but the anti-counterfeiting parties have failed to imitate the above items. In addition, at present, anti-counterfeiting inks are made of invisible fluorescent compounds, photoelectric conversion substances, special chemical reagents, animal and plant DNA, monoclonal antibodies, or specific antibacterial substances such as ultraviolet, infrared, and X-rays to make a new type of anti-counterfeiting ink.
The seals stamped with the above-mentioned ink or ink paste have the same appearance as ordinary seals, but they have a special residual effect when detected by the corresponding method.
11. Reactive Color Change Ink The various chemical substances added to the ink, under certain conditions, can produce a variety of chemical reactions, so that the ink changes color, to achieve anti-counterfeiting purposes. Some of the heat-sensitive anti-counterfeiting inks (thermochromic inks), pressure-sensitive color-changing inks, and humidity-sensitive color-changing inks mentioned above are reaction-change color inks. In addition, there are also used acid-base indicator added to the ink. After printing into a trademark, a color change agent is encountered and the color of the ink can be changed to achieve the purpose of anti-counterfeiting.
In addition, there are some anti-counterfeit inks such as: optical variable ink, fragrance ink, conductive ink, jet ink, matte ink, microwave ink, electronic radiation ink, laser ink, gem ink, metal etching ink, etc. The relevant chapters of the book have been described.

Second, the use of anti-counterfeiting inks There are many types of anti-counterfeit inks. With the development of science and technology, new anti-counterfeiting inks are emerging. In general, people study the characteristics of anti-counterfeit inks more, but the application of anti-counterfeiting inks. However, it has not been discussed enough, resulting in the use of anti-counterfeiting ink packaging can not achieve the results of effective anti-counterfeiting. Therefore, it is necessary to discuss the application of anti-counterfeiting ink, so that the anti-counterfeiting ink can really play the role of packaging anti-counterfeiting.
1. On-line use of security inks The use of security inks is now mostly in the form of trademarks. After the printing company submits the trademark to the packaging company, the packaging company attaches it to the packaging container. The disadvantages of this procedure are