Matters needing attention in the application of th

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Matters needing attention in the application of printing pearlescent ink

in recent years, with the rapid development of China's printing industry, the ink manufacturing industry has also developed and expanded, especially the market prospect of special types of ink is promising. As one of the special kinds of inks, the market prospect of pearlescent inks is widely optimistic by insiders. Pearlescent inks have strong competitiveness and development potential in the packaging of high-end cosmetics, the printing of high-end trademarks and promotional materials

the printing effect of pearlescent ink is generally determined by the actual reflection of vision on pearlescent effect, brightness and color effect. The effect of products varies greatly with different printing methods. The commonly used printing pearlescent inks mainly include silk screen printing, gravure printing, offset printing, flexible version pearlescent inks, etc. among them, offset pearlescent inks have delicate pearl luster and strong light refractive index, which can greatly improve the grade of printed products. The product packaging produced by them is not only beautiful, but also has a certain anti-counterfeiting effect, which is favored by the majority of businesses and consumers

all packaging materials and labels have naturally become difficult for the R & D team of Haizheng polylactic acid to crack. Labels can be printed with pearlescent pigment offset printing ink. Compared with silk screen printing and flexo technology, the application of offset pearlescent ink is relatively difficult. Due to the viscosity contrast, if the recyclable design of packaging is given from the beginning, it is higher. At the same time, pearlescent pigment is particles ground with shells, which are difficult to dissolve in it, As a result, it is difficult to mix pearlescent pigments and offset printing inks. Even if they are mixed together, the distribution of pearlescent pigments is uneven. This means a great challenge for offset printing. In the application process of offset pearlescent ink, not only the reasonable allocation of ink and the correct selection and careful treatment of substrate, but also the selection of appropriate printing equipment and the application of advanced technology in printing according to the characteristics of pearlescent pigment, so as to achieve the best pearlescent effect

I. brittleness and fineness of pearlescent pigments

at present, commonly used pearlescent pigments are generally composed of anatase or rutile titanium dioxide coated mica flakes. The flake structure is very brittle and easy to be damaged. At the same time, the requirements for pigment fineness of offset pearlescent ink are very strict, such as the particle fineness of mica titanium pearlescent pigment is less than 25 M. If the pigment particles are too thick, the transferability of pearlescent ink is poor, but if the pigment particles are too fine, the pearlescent effect will be affected

II. Viscosity and fluidity of ink

the particularity of offset pearlescent ink pigment requires that this ink has low viscosity and high fluidity compared with other ordinary inks, so that it can meet the floatability requirements of pearlescent pigment during printing, so as to achieve the ideal pearlescent effect

III. transparency of ink

the pearlescent effect of pearlescent ink depends on the refraction and interference of incident light. Therefore, the transparency of offset pearlescent ink has a great impact on the pearlescent effect. If the transparency of the ink layer is poor, the originally sufficient light will be absorbed and affect the pearlescent effect

precautions for the use of offset pearlescent ink printing

1. Selection or treatment of substrate. The surface of the substrate should be as smooth and flat as possible to make the pigment arrangement and orientation better. Because the ink layer in offset printing is relatively thin, it is very important to obtain the ideal pearlescent effect

2. The pigment particles are large and easy to block the version. If blocking and foaming are found, stop the machine immediately and thoroughly clean it with alcohol water

3. Pay attention to the control of drying speed

the printing ink layer of offset pearlescent ink is relatively thick, and the drying speed of the ink is slower than that of ordinary offset ink. At this time, the method of adding desiccant can not be used to adjust, but the temperature and humidity of the paper and printing environment need to be controlled. The ambient temperature should be controlled at 253 ℃, and the relative humidity should be controlled at about 55%. Do not accelerate and heat the high temperature to dry rapidly

4. Try not to choose eye tone printing

pearlescent pigments need to be arranged in order to achieve satisfactory pearlescent effect. Eye tone printing is not conducive to the orderly arrangement of pigments. Relatively speaking, pearlescent ink is more suitable for the printing of field color blocks

5. Pay attention to the control of the amount of ink

the coarse particles of pearlescent pigment will also lead to the large amount of ink. If the particles are too coarse, the pearlescent pigment will leave residues in the ink, which is difficult to separate, and will lead to the waste of ink. When using pearlescent ink, it is necessary to ensure that it is used within the warranty period, and it must be stirred evenly

6. Pay attention to the balance of water and ink

because the offset pearlescent ink is relatively thin and soft, it is easy to emulsify in the printing process, so it is appropriate to control the water supply to the minimum and adjust the pH value of the fountain solution to about 5 without dirty version

7. Control the peculiar smell of printing products. Some products (such as cigarette packs) have strict requirements on the smell of packaging. Although the smell of pearlescent pigment itself is not big, if the pearlescent ink is not adjusted well, it is easy to cause a large peculiar smell produced by the product. By improving ink and printing equipment, this problem can be effectively avoided

in addition, do not press the printed matter heavily when stacking, and try not to stack and overlap too much after drying, so as to avoid the pearlescent pigment particles being crushed and affecting the pearlescent effect. In order to improve the wear resistance, temperature resistance, gas insulation and maintain its gloss of the ink layer surface, the surface can be coated with gloss paint or pasted with protective film

treatment of some problems in printing 4 billion file envelopes

1. Printing is dirty

spray powder appropriately, and control the appropriate stacking height; Improve the printing machine speed and reduce the dry plate time; Reduce the distance between the cutter and the pressure roller

2. Poor pearlescent effect or no pearlescent effect

first check whether the points of the version are blocked or need to be cleaned. Whether the dot of the plate is too shallow to achieve the required effect, check whether the viscosity of the pearlescent ink matches the vehicle speed properly, check whether the angle of the scraper is too large or the pressure is too high, and check whether the distance between the scraper and the pressure roller is too long to dry the plate

3. It has pearlescent effect but has no gloss

the diluent volatilizes too fast. It should be combined with slow drying diluent to reduce the oven temperature or cold air At the same time, the printing speed is accelerated and the viscosity of the ink is increased

4. The peel strength difference after printing is compounded

correctly select the purpose of pearlescent ink, and determine the surface printing or internal printing. Choose suitable glue and thinner. Control the gluing amount, temperature, tension, etc. during compounding. Grasp the corona treatment of the film. For self-made pearlescent ink, appropriate diluent should be selected to adapt to the composite glue

offset pearlescent ink requires high printing technology, and minor negligence in every link of the printing process may affect the pearlescent effect. In addition, the pigment particles in the ink itself are relatively thick, so it is necessary to cooperate with advanced printing technology to achieve the desired effect during offset printing

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