Offset ink preparation and printing points (below)

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.

Source: Comin Media