Pearlescent Printing can create a new color space and light color effect through the organic combination of individualized design and printed quality. The printing substrate not only beautifies and protects the products by printing and decorating all kinds of graphics. At the same time, it has beautified the human living environment and space with its unique new humanistic concept, and expressed the common pursuit of people. So that people enjoy more rich and fantastic colors.
Pearlescent flexographic printing ink is a kind of liquid ink similar to Newtonian fluid, low viscosity and high concentration. It is divided into three types: solvent type, water-based type and photo-curing type. In order to maximize and fully demonstrate its pearlescent effect, the transparency of the binder, colorant, etc. used to formulate the ink is first. In the production process, the ink must be in the best state of miscibility. It is necessary to ensure that the ink layer of the printed product can receive sufficient light without losing a large amount of light, so as to exhibit the special optical interference function of pearlescent light, increase the depth and layering of the color, change the crystal clear, colorful, pearl Glossy elegant visual effects.
Pearl ink use method:
Due to the large proportion of pearlescent inks, be careful to thoroughly and evenly stir the pearlescent ink inside the drum before putting it on. In the printing process, as with gold ink, use a recirculating ink supply device with a closed squeegee as much as possible to avoid sedimentation, resulting in color differences and color shifts before and after printing.
Choose a suitable flexographic plate to avoid poor transfer of ink or the occurrence of a plate-laying phenomenon. According to the printing substrate, printing speed to carefully adjust and care for the viscosity of pearlescent ink and drying speed. In general, the ink has a viscosity of 50 to 60 sec (4 cup/25°C). Printing coated paper and film, suitable viscosity of 20 ~ 30sec (4cup/25 °C); printing cattle cardboard, gray paper, etc., a suitable viscosity of 30 ~ 60sec (4cup/25 °C). (Printing speed 120m/min, the lower the speed, the higher the viscosity of the ink.)
The printing adaptability and transmissibility of pearl ink have their own characteristics. The material of the anilox roller has a decisive influence on the transferability of the flexographic ink. The ceramic anilox roller has the best effect for pearlescent flexographic printing due to its special ink hole shape and excellent adsorption and release of ink and ink. Pearlescent flexographic printing requires that the fineness of the pearlescent ink match the number of anilox roller lines. The pearlescent ink particle size is larger than the traditional ink particle size, so in order to ensure the printing quality, some printing conditions must be adjusted, such as reducing the number of anilox roller lines to match the transfer of larger particles of ink, which also makes the ink layer thicker, so To adjust the drying temperature, at the same time pay attention to the smoothness of the paper. The pearlescent effect depends on the amount of ink transferred to the substrate. The thicker the ink layer, the more glossy pearlescent. For this reason, it is recommended to use an anilox roller with a depth of up to 50 μm. According to the standard of printed products, the best printing effect can be obtained by adjusting the printing speed. When printing, it is best to maintain a brief leveling of the ink after it has been transferred to the substrate, so that the pigment crystals are optimally aligned with the surface of the substrate.
Ink fineness and anilox roller number correspondence table:
Pearlescent ink is selected according to the design and decoration characteristics of printed products: full-page printing, it is recommended that you use pearl ink of 10 ~ 60μm or thicker, because of its good transparency, so that the printed product has a crystal clear, flickering texture; if it is local printing, Choose delicate 5 ~ 25μm, pearlescent ink with strong coverage, so that prints soft and elegant gloss, silky feeling, such as satin-like smooth.
Pearlescent brightness and viscosity The brightness of pearlescent ink is directly proportional to its viscosity, otherwise, it is difficult to meet the brightness requirements of printed products. If the brightness is not enough, adjust the squeegee angle, increase the thickness of the ink layer, and increase the brightness.
Ink layer thickness and drying speed With the thickening of the ink layer, it is necessary to increase the drying temperature at the same time, increase the air volume, so that the ink film is quickly and completely dried, and the gloss effect is improved.
After the smoothness and pearlescent effect of the printed substrate are printed, whether the arrangement of the coloring pigments in the ink layer of the printed product is parallel to the substrate determines the pearlescent effect. The main factors influencing the pearlescent effect of printed materials are: the nature of the ink, the transfer method of the ink, the printing process, and the type of the substrate to be printed. The smoothness and smoothness of the printing materials have a crucial influence on the arrangement of the pigments. The better the flatness of the substrate is, the more favorable the formation of the mirror surface is, so that the incident light can be multiplely refracted on the level where these optical refractive indexes are different, thereby exhibiting an excellent pearl natural color effect. On the contrary, if the colored particles are scattered and disorderly, resulting in diffuse reflection of the incident light, it can be imagined that the pearlescent effect will be greatly weakened, and it is difficult to achieve the beautifying effect of pearlescent light. Of course, for a large-particle size pearlescent ink, its glittering effect does not depend only on the smoothness of the substrate.
Covering the light - a layer of varnish on the top of the cover, not only perfectly protects the ink layer, but also makes the finishing touches and icing on the cake. According to the speed, adjusting the viscosity, viscosity, fluidity, pH stability, drying speed and leveling of the varnish, it is important to properly and economically handle the post-printing glazing process. After the surface of the printed material is calendered or embossed, the pearlescent effect will be significantly improved. Printed on dark paper and embossed to produce a special visually appealing gift wrap, unbleached kraft paper can be produced with metallic luster after being printed by pearlescent and then calendered. Such follow-up processes can add bright colors to pearl printing products. (Luoyang Bailinwei Ink Co., Ltd. Wu Tiejun)