Packaging anti-counterfeiting discussion (3)

Security ink

3.1 Optical color ink

The ink technology is high in content and expensive. The import price is several thousand US dollars per kilogram, and the national product is also more than 10,000 yuan per kilogram. With this ink printed pattern and mark, under the ordinary light, not only has the brilliant interference color and the metallic gloss effect, but also has the magic corner color change function. When we rotate the print plane angle, we can clearly see that the color of the pattern or mark (reflection color) changes with the change of the rotation angle.

3.2 UV fluorescent ink

Ultraviolet fluorescent ink is a special ink that emits visible light (400-800 nm) under the irradiation of ultraviolet light (200-400 nm). According to the different wavelengths of excitation light source, it can be divided into short-wave ultraviolet excitation fluorescence anti-counterfeiting printing ink (excitation wavelength 254nm) and long-wavelength ultraviolet laser fluorescence anti-counterfeiting printing ink (excitation wavelength 365nm).

According to whether the color of the ink is divided into two kinds of colored fluorescent ink and colorless fluorescent ink. There are mainly three kinds of fluorescent materials commonly used in their composition. 1 Organic fluorescent materials are unsaturated molecules with a large total weight of light, most of which are excited by sunlight, used for the obvious decoration of color, and have poor fluorescence stability and are easily oxidatively decomposed; 2 The high-temperature synthetic inorganic fluorescent material is a luminescent material used for fluorescent screens and fluorescent tubes. It has good resistance to radiation and high stability, but it is difficult to disperse in oily media, it is difficult to synthesize and has poor water resistance. 3 Chemical synthesis of rare earth organic chromium As a fluorescent material. The conventional organic rare earth fluorescent chromium complex has simple equipment, is easy to disperse, dissolve and refine in oily medium, is colorless under visible light, and exhibits strong fluorescence effect under ultraviolet light excitation.

3.3 Daylight excitation color change security ink

Sunlight-activated color-changing anti-counterfeiting ink is an anti-counterfeiting printing ink that emits visible light (400-800 nm) under sunlight. This ink is discolored on the surface due to the action of the sun and is actually discolored by ultraviolet rays. At present, several kinds of such inks that have been developed and applied on the Chinese market have a color changing effect under sunlight (also under ultraviolet light); they can change from colorless to purple, blue, yellow, etc., and can also be designed from colored to colorless. Change is the rookie and wonderful thing for security materials.

3.4 Thermal security ink

Thermal security ink is under the effect of heating, can produce discoloration effect of the 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. Hand-type color change security ink refers to the 34-36 °C temperature, can produce discoloration effect of the ink. According to the difference in color change, it can be divided into single color reversible, multi-color reversible and multi-color irreversible thermal ink.

Now China has developed five kinds of hand-temperature single color reversible ink, color change methods are: rose red becomes colorless, purple becomes colorless, blue becomes colorless, green becomes colorless, orange red becomes colorless; can also be designed Change to a variety of other colors for coloring. The three kinds of high-temperature single-color reversible security ink discoloration methods are: pink to blue, yellow red, red and black. Thermochromic substances can be classified into inorganic salts, coordination compounds, organic substances (dye molecules) and liquid crystal polymers.

3.5 reaction color change ink

Chemical substances in ink, under certain conditions, can produce a variety of chemical reactions, so that the ink changes color, to achieve the purpose of anti-counterfeiting. Part of the heat-sensitive anti-counterfeit inks, pressure-sensitive color-changing inks, and humidity-sensitive color changes are all color-changing inks. The use of acid indicator added to the ink, after the printing of the trademark, encounter color change agent, can also make the color of the ink change, to achieve the purpose of anti-counterfeiting.

3.6 magnetic ink

Magnetic ink is a special ink made by mixing magnetic iron oxide powder into ink. At this stage, magnetically encoded texts and symbols, which are mainly used to print bank tickets, have the effect of recording and storing information. A magnetically encoded ticket can be inserted into a magnetic code reader to identify authenticity. It is used in packaging and decoration and has strong security.

3.7 Biochemical reaction ink

This type of ink is compounded with substances that produce biochemical reactions. First use this ink to make a mark that is not visible to the naked eye on the packaged products and the products requiring anti-counterfeit. Then, according to the formula, the chemical reagents are selected, and when the operation is performed by means of micro heat, moistening, rubbing, etc., it will be revealed. The text or pattern, the chemical composition of the ink is more complex, some top secret documents, important tickets, etc. are printed using this ink.

3.8 LCD Ink

Compounds with crystalline properties were added to the liquid crystal ink. Under the influence of weak current and temperature, the liquid crystal displays bright and dark patterns and colors due to crystal changes. The printing and decorating products printed with this ink can react with changes in temperature; if used for printing calendars, it will show different colors as the temperature of the four seasons changes, and it is a very new ink material with vitality. The promotion of its use in the field of packaging and decoration, its anti-counterfeiting effect is incalculable.