Pearlescent ink analysis

In recent years, China's ink manufacturing industry has developed rapidly. The total production capacity of ink in the country has reached about 300,000 tons, ranking fourth in the world.

The quality and technical indicators of major domestic ink manufacturing companies have reached or approached the advanced level of similar foreign products. In addition to basically satisfying the needs of the domestic printing industry and the packaging and decorating industry, they have also been exported to more than 50 countries and regions in the world and achieved export earnings. . However, we must realize that compared with the international advanced level, China's ink manufacturing industry still has a certain gap, mainly in the production process and the level of tooling lag, the poor consistency of the quality of domestic raw materials, scientific research and development capabilities and analytical methods need to be further improved. Poor environmental awareness. The key targets for the development of the ink industry in the future are commercial web offset inks, high-grade offset inks, environmentally friendly inks, and special inks. Offset pearlescent ink is one of the special inks. This article will discuss with you the composition, characteristics and application of offset pearl ink.

Offset pearl ink composition

Offset pearlescent ink is a part of the lithographic special ink. Its print has delicate pearlescent luster and strong light refractive index, which can improve the grade of printed matter. It is mainly used for printing high-end packaging, trademarks and pictures.

Offset pearlescent ink consists of pearlescent pigments, binders, fillers, additives, etc., and has a certain degree of fluidity of the paste adhesive, after mixing and mixing evenly, it can show soft pearlescent effect after drying on the substrate.

Pearlescent pigment

Pearlescent pigment is a new type of pigment that is neither soluble in water nor soluble in linking materials. This pigment can reproduce pearl luster possessed by pearls and shells. As early as the 17th century, pearlescent pigments began to be produced on the European continent. At present, the most common pearlescent pigments are composed of anatase or rutile titanium dioxide coated mica flakes, which can exhibit a variety of delicate, soft silvery white luster. This elegant and generous The color is more and more loved and accepted by people.

2. Binder

The binder is an adhesive fluid. As its name suggests, it acts as a link. It is a mixture of powdered pearlescent pigments and other substances that are mixed together to form a paste with a certain degree of fluidity. The binder is the main flow part of the ink and is the heart of the ink.

3. Filler

The filler is a white transparent, translucent or opaque powdery substance. It is also a solid part of the ink and plays a major role in the filling of the ink.

4. Additives

An additive is an additional part of the ink except for the main part, which plays a role in adjusting the performance of a certain aspect of the ink, mainly depending on the product characteristics and requirements.

Preparation of offset pearlescent ink

1. Offset pearl ink basic formula

The basic formula of offset pearlescent ink is as follows.
Pearlescent pigment: 20% to 50%
Material: 30%～70%
Filler: 10% to 20%
Auxiliaries: 1% to 10%

2. Production process

Due to the peculiarity of pearlescent pigments, it is not allowed to grind like ordinary inks during the dispersion process, otherwise the structure of pearlescent pigments will be damaged, and the gloss and pearlescent effect of printed matters will be affected.

3. The main technical parameters

Fluidity: 32～42mm
Stickiness: 6-10
Pearl effect: good

Offset printing ink characteristics

1. The vulnerability of pearlescent pigments

Pearlescent pigments are composed of anatase or rutile titanium dioxide coated mica flakes. The sheet structure is very brittle and extremely easy to break, thus affecting the pearlescent effect.

2. Fineness of pearlescent pigments

Offset pearlescent inks have stricter requirements for fineness of pigments, and the fineness of the commonly used mica titanium pearlescent pigments is below 25 μm. If the pigment particles are too coarse, the transferability of the pearlescent ink is poor, but if the pigment particles are too fine, the pearlescent effect of the print will be less pronounced.

3. Transparency of Offset Pearlescent Ink

The pearlescent effect of offset pearlescent ink depends on the refraction and interference of the incident light. Therefore, the transparency of the offset pearlescent ink has a great influence on the pearlescent effect. If the transparency of the ink layer is poor, the original sufficient light will be absorbed and affect the pearlescent effect. Therefore, when selecting the ink binder and the filler, it is necessary to select a material with good transparency.

4. Viscosity and fluidity of offset pearlescent ink

The special nature of offset pearlescent ink pigments requires that the inks have lower viscosity and fluidity than other common inks, and can meet the floating requirements of pearlescent pigments during printing to achieve the desired pearlescent effect.

Offset pearl ink printing notes

1. Not suitable for halftone printing

Since the pearlescent ink pigment used is a sheet of anatase or rutile titanium dioxide coated mica flakes, pearlescent pigments need to be arranged in order to achieve a satisfactory pearlescent effect. The mesh printing is not conducive to the orderly arrangement of pigments, so the pearlescent ink is more suitable for the printing of solid color patches.

2. Printing sticky

Pearlescent ink printing is particularly prone to the phenomenon of dirty printed matter, this is because the offset printing pearlescent ink has a small viscosity, fluidity, pearlescent pigment particles, and more used to print the field, with a large amount of ink, generally ordinary offset ink 2 to 3 times, printing ink layer is relatively thick, prone to dirt. Therefore, it is necessary to spray dust properly and control the proper stacking height.

3. Drying speed

The printing ink layer of offset pearlescent ink is relatively thick, and the drying speed of the ink is slower than ordinary offset printing ink. At this time, it is not possible to adjust the method of adding a desiccant, but it is necessary to control the temperature and humidity of the paper and the printing environment. The ambient temperature should be controlled at 25±3°C, and the relative humidity should be controlled at about 55%.

4. Water and ink balance

Because the offset pearlescent ink is relatively soft and easy to emulsify in the printing process, the amount of water to be fed is controlled to a minimum under the condition of not contaminating the plate, and the pH of the fountain solution is adjusted to about 5 or so.

Development of Offset Pearlescent Ink

Ten years ago, due to the restrictions on the quality of pearlescent pigments, the prices of well-known foreign brands were too high, and the quality of domestic products was unstable. Therefore, the production and sales volume of inks has been very small, which constrains development. In recent years, the birth of a new type of mica titanium pearlescent pigments has brought pearlescent pigments to a new level of product quality and grade. Pearlescent pigments produced in China can basically meet the requirements for the use of mid-range offset pearlescent inks. High-grade offset pearlescent inks still need to be imported, but the price has declined, which has brought opportunities for the development of offset pearl inks. Mica titanium series pearlescent pigments are non-toxic, stable, and rich in hue, and its greatest success is that the fineness of the particles can meet the requirements of offset printing. It solves the problem of oversized pigments and poor transferability of overprinted pearlescent inks for many years. Offset pearlescent inks have achieved rapid development. Printed products using pearlescent inks are favored by the market and favored by users.

Judging from the current printing industry's market, the rough calculation of the annual amount of offset printing pearl ink is about 20 to 30 tons, which mainly depends on imports and domestic large-scale ink manufacturers. Although the current market share and the amount of offset printing pearl ink is still relatively small, but with the flourishing development of China's printing industry, the market prospects of pearlescent ink is also optimistic about the industry, especially in the packaging of high-end cosmetics, high-end trademarks and promotion For the printing of products, pearlescent inks have strong competitiveness and development potential. Pearlescent ink belongs to the ranks of inks with rapid development in the future, and its growth rate will exceed 20%. However, due to the small base of offset pearlescent ink itself, the total growth will not be large.

Reprinted from: Ink Information