Ink Industry Status and Development Trends (4)

6, screen printing ink

Screen printing is the main one in stencil printing. The screen printing method is very flexible. It can be completely printed by hand or semi-automatically. It can also be fully automatic and continuous. The shape of the substrate is not limited. It can be conveyed by sheets, plates, and equipment. The variety of substrates includes paper, cardboard, plastic films and products, metals, ceramics, wood, and fabrics. This requires a variety of screen printing inks.

According to the classification of substrates, they can be divided into paper and screen printing ink [offset printing ink], plastic screen printing ink, textile printing ink, glass screen printing ink, ceramic decal paper ink, etc. According to the composition of the link material, there are oxidized conjunctiva resin ink, volatile dry solvent ink, and two-component reactive ink.

In addition, there are UV inks, luminescent, fluorescent, and light-storing inks. The special color inks, such as liquid crystal, conductive, magnetic, etc., that exhibit temperature change, microcapsule structure [braille, fragrance, foam], etc., can all be printed by screen printing.

7, security ink

Security inks are inks with anti-counterfeiting properties. The ink is composed of a colorant, a binder, and an ink additive 3 part. Anti-counterfeiting ink, so it can use anti-counterfeiting is the use of pigment in the ink or linked with a special function of anti-counterfeiting. Such as: photosensitive anti-counterfeiting ink, thermal security ink, pressure-sensitive anti-counterfeiting ink, magnetic anti-counterfeiting ink, anti-printing ink and so on.

[1] Photosensitive security ink

Photosensitive security ink is an 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. Photosensitive anti-counterfeit inks mainly include ultraviolet fluorescent inks, sunlight-induced color-changing inks, and infrared anti-counterfeiting inks.

A, UV fluorescent ink, can emit visible light (400-800nm) ink under ultraviolet light (200-400nm) irradiation. Usually refers to the short-wave ultraviolet excitation can see my security printing ink, the wavelength of 254nm long wave. Ultraviolet excitation visible security printing ink, the wavelength of 365nm.

According to whether the color of printing ink is divided into colored fluorescent ink, colorless fluorescent ink two. The former is the addition of fluorescent compounds to colored inks, the latter being added to colorless inks; the former is printed with the naked eye and the latter is invisible.

B. Sunlight-induced color-changing inks can emit anti-counterfeit printing inks with visible light of 400-800 nm under the irradiation of sunlight. This kind of ink is discolored from the application due to the action of sunlight, and is essentially discolored by ultraviolet rays.

C. Infrared anti-counterfeit inks, which use the absorption characteristics of infrared [700-1500nm] matching, are made of ink, and can be detected or recognized by the instrument. It is made by adding a pair of substances that have different absorption characteristics for infrared rays to the ink. The products printed with infrared ink have no response under normal light, and under the detection of infrared light, corresponding signals and graphics can be observed.

In recent years, China's UV fluorescent inks have developed rapidly. They have successfully developed colored [visible] ultraviolet fluorescent inks and colorless [stealth] ultraviolet fluorescent oil blacks. These fluorescent inks can emit red fluorescence and blue light respectively under specific ultraviolet light irradiation. Fluorescent, yellow fluorescent and green fluorescent UV fluorescent inks. These UV fluorescent inks have been widely used. Colorless fluorescent inks are printed on the front right and bottom left corners of the 1990 edition of RMB 100 in China, and the words “yellow” and “YIBAI” are displayed under the irradiation of a violet light.

A colorless fluorescent ink is printed on the front side of the 1990 RMB version of the front seatbelt of China's 100 yuan. Under ultraviolet irradiation, 100 words of yellow are printed on the purple border, indicating that the invisible yellow fluorescent ink and the invisible purple fluorescence have been printed. Ink.

The tax stamp on the national unified invoice is printed with colored ultraviolet fluorescent ink. The tax stamp on the invoice during the day is the same as that of the general unit seal. When the invoice is illuminated with violet light in a dark, dark place, the tax stamp is bright red. The general unit's chapter appears black.

[2] Thermal security ink

Thermal security ink is the color of the color in the ink and the color change with the temperature. For example, pink cobalt chloride. Hexamethylenetetramine [C0CL2.2C6H12N4.10H2O], when the temperature rises to 35°C, loses crystal water [C0CL2.2C6H12N4] and turns sky blue. When the temperature drops, the substance absorbs the moisture in the air and gradually returns to its original pink color. For another example, the red cube of mercury sulfonate [Hg12], when heated to 137°C, turns into blue orthorhombic crystals. After cooling to room temperature, it returned to the original blue crystal.