Colorful security ink

Anti-counterfeiting ink is an extremely important anti-counterfeiting technology field. It has a wide range of applications and involves many disciplines. It is a special ink that has been specially developed to add some special substances to the ink and has an anti-counterfeiting function. It is used in the printing of security printing products. Its recipes and processes are confidential and should be managed strictly; its products should also be fixed, regularly supplied to designated manufacturers, set up special machines for use, and prevent proliferation.

Photosensitive security ink
Ink that emits visible light when exposed to light. The light here refers to: Visible and invisible light such as ultraviolet light, infrared light, and sunlight.

a. Ultraviolet Fluorescent Ink: Can emit visible light (400nm-800nm) ink under ultraviolet light (200nm-400nm) irradiation. Generally refers to the short-wave ultraviolet excitation visible fluorescent anti-counterfeit printing ink, excitation wavelength of 254nm, long-wave ultraviolet excitation visible fluorescent anti-counterfeit printing ink, excitation wavelength of 365nm.

b. Sunlight-induced color-changing inks: Under the sunlight, they can emit visible light 400nm-800nm ​​anti-counterfeit printing ink. This kind of ink is discolored from the application due to the action of sunlight, and is also substantially discolored by the irradiation of ultraviolet rays.

c. Infrared anti-counterfeit ink: A type of ink that is matched by infrared absorption (700nm - 1500nm) with different absorption characteristics, and can detect or identify its mark by the instrument. A pair of substances that have different absorption characteristics for infrared rays are added to the ink. Products printed with infrared inks have no response under normal light, but under infrared light detection, corresponding signals or images can be observed.

Thermal security ink
The effect of heat, the ink that can produce discoloration effect. Usually divided into reversible and irreversible thermal discoloration security ink; usually refers to the color temperature of 34 degrees Celsius - 100 degrees Celsius. The hand-warming security ink is a kind of thermal discoloration and anti-counterfeiting ink. It refers to the ink that can produce discoloration effect under the temperature of 34 degrees Celsius to 36 degrees Celsius. The principle of thermochromism is to cause the physical change or chemical change of the color changing compound under the heating condition to bring about its own change of the light absorption property.

Pressure-sensitive security ink
Under pressure rubbing, color inks can appear. It is made by adding special chemical agents or color changing substances to the ink. Colored or invisible graphics printed with this type of ink, when rubbed and pressed with a hard object or tool, that is, a chemical pressure change occurs or the microcapsule breaks down the dye and the color appears (red, blue, ink, Green, purple, yellow, etc.). The color of the display can be selected according to the user's requirements and the design is memorized.

Magnetic security ink
A security printing ink made with a magnetic powder material as a functional component. It is the most commonly used anti-counterfeiting ink. Its prominent feature is the deep color appearance, simple detection equipment, and more often used in ticket security.

Optical variable security ink
The multilayer optical film flakes, which are capable of optical interference, were prepared as dispersions. The inks were completely different in color when the incident angles of light were 90 degrees Celsius and 30 degrees Celsius, respectively. This technology is extremely complicated and expensive. There are few countries that can produce it, and it has been adopted on foreign banknotes.

Anti-flood security ink
An ink that has a color-developing chemical reaction to a chemical used for alteration. Common types include anti-counterfeit phosphors, temperature discoloration powders, anti-counterfeit fluorescent filaments, UV anti-counterfeiting fluorescent inks, infrared anti-counterfeit fluorescent inks, anti-counterfeiting thermal inks, warming discoloration and sunlight discoloration inks (such as under the sun discoloration and UV lamp Photochromic inks that change color under the condition of thermochromic inks that change color at different temperatures. These anti-counterfeit products can be widely used in tobacco, wine, food, printing, paper making, textile, famous brand clothing signs and other fields, and have unique anti-counterfeit effects.

Reprinted from: China Packaging Industry