The use of scientific and technological means continues to pursue the history of beauty. At present, pearlescent pigments have been widely used in various sectors of the national economy and people's daily lives, bringing beauty to people, and creating a colorful and colorful world.
With the rapid development of the packaging and printing industry, pearlescent pigments have been used more and more widely in the packaging, printing and publishing industries. From cosmetics, cigarette packs, alcohol, gift packaging, business cards, greeting cards, calendars, book covers, and pictorial printing. The market demand for pearl film for textile printing and food packaging is increasing day by day, such as ice cream, soft drinks, biscuits, candy, napkins, etc. The use of pearlescent film gives consumers a pleasing sensation.
The production processes of several types of pearlescent pigments (titanium series pearlescent pigments) currently sold on the market are very complicated, the process precision and equipment requirements are high, the manufacturing cost is high, and the widespread application of such pigments is limited on the sales price. For example, many paint manufacturers and ink manufacturers have been very interested in this kind of pigment, but they have been deterred from the high prices in practical applications. Therefore, reducing production costs and realizing large-scale production are very crucial steps in expanding the market. This is one of them. The second is the application of pearlescent pigments is still in a very weak link, the current application of pearlescent pigments in coatings, plastics, printing inks, artificial leather, construction materials, cosmetics, paper, packaging materials, textile printing, printing and dyeing applications. Research and development has just begun. Since most people still know little about the characteristics of this new type of decorative pigment, coupled with the lag in application technology, it is still in a state of low technical level and poor decorative effect, which restricts the application and promotion of pearlescent pigments. Therefore, many should be able to use this kind of pigment to decorate to enhance the added value of the products, and helplessly lose the excellent competition opportunities. Because people are clearly aware of a truth: an application of technology breakthroughs will often promote the upgrading of an industry's products, will bring an incalculable economic benefits to an industry. Thirdly, due to the seeming simplicity of the pearlescent pigment production process, the production technology in practice is complex and involves many subjects. Therefore, all countries in the world have kept strict confidentiality and blockade. In order to keep trade secrets, many companies have never disclosed their annual sales performance. Compared with some industrially developed countries, the research, production, and application of mica titanium pearlescent pigments in China are still in the initial stage of development. Regardless of product quality, variety, and application technology level, they are all at a low level, and many technical key issues No breakthrough has yet been made, and paint companies in Germany and Japan still dominate the world.
Under the above circumstances, how can we face it? This is a matter of great concern to people. Now let us analyze some of the situations in the use of mica titanium pearlescent pigments. Pearlescent pigment is a glossy pigment. Its glittering effect is passive light, that is to say it will show a flash effect under the condition of light. The pearlescent effect of pearlescent ink (print fabric ink, commonly called printing paste) is mainly determined by the pearlescent luster of the pigment. This is an important property for the printing ink. It depends on the pearlescent pigment in the ink. The shape, content and uniformity of the dispersion, and the uniformity of the dispersion and the ink formulation process, under the condition of ensuring that the pigment in the ink is uniformly dispersed, it has been studied the influence of the amount of pearlescent pigment in the textile screen printing ink on pearl luster. The same ink formulation was used to change the amount of pearlescent pigments used in the ink. The pearlescent effect was evaluated visually. The structure was found to increase the percentage of pearlescent pigments in the ink. When the amount of pigment was 5%, The gloss effect is poor. When the dosage is 12%, the pearlescent effect is better. When the amount is 15%, the pearlescent effect is the best and the fastness is also good. When the amount of pigment is further increased to 17%, the pearlescent effect and amount is 15%. When the time is similar, the pearlescent effect no longer increases when the dosage is further increased. This shows that one reason, blindly seeking to increase the amount of pearlescent pigments, can not significantly improve the effect of pearlescent, when the amount of pigment reaches a certain value, the pearlescent effect will no longer play its role. As a result of such additional amounts of pigments, one is to increase the cost of the ink; the other is to reduce the printing fastness of the ink. In order to ensure the ink's printing adaptability, it was suggested that the amount of pearlescent pigment should be controlled within the range of 12% to 15%. In addition to the above dosage, the pearlescent effect is related to the shape of the pigment. The flat flaky crystal should be the basic structural form of the pearlescent pigment. Only in this way can the pearl luster be reflected as strongly as the lens, and the aspect ratio of the flat platy crystal. It is best to be around 200, and the material that meets this condition is very scarce. At present, the most widely used and widely used pearlescent pigments in the world are based on natural mica flakes, which are coated with one or more layers of titanium or other metal oxides through special chemical processes. Therefore, to measure the quality of pearl ink, it depends on the use of flake pigments in ink formulation. Is there any other means to reduce the amount of pearlescent pigment in the ink? The smaller the amount, the lower the ink cost. Will the attraction of pearlescent ink be greater? The answer is yes. How to reduce the amount of pigment, which is how to make the flaky pearlescent pigments oriented in parallel, if the flaky pearlescent pigments can be arranged in parallel on the surface of the upper layer of the ink layer, even if there is no pigment particles in the middle layer or the bottom layer of the ink layer, it will not affect Pearlescent effect, because the light is intercepted by the upper layer of flake particles, the pigment particles in the middle and bottom layer will not be reflected or refracted by the light, so the particles will be useless again. Because of this, the titanium pearlescent pigment of mica is called Functional pigments.
The higher the degree of parallel orientation of the flake pigments, the more pronounced the pearl luster effect, and how can the parallel orientation of the flake particles be increased? What are the factors that affect the parallel orientation of the flake particles? These are issues that people are extremely concerned about.
First, with the pearl ink preparation process
1. Determinants of pearlescent pigment ink quality
The quality of the pearlescent pigment ink depends to a large extent on the wetting and dispersion of the flake pigment by the resin carrier and the degree of parallel orientation in the ink film. The former is determined by the structure and properties of the chosen resin itself, and the latter depends on the design formula of the ink and the correct implementation of the printing process. The resin carrier is the basis, and the recipe design and printing process are the key. The ideal ink should have a relatively low solid content. For this reason, the amount of pearlescent pigment used should not be too much, because too many pigments tend to be intensive and irregular, and are easily misaligned. Because of the chaotic arrangement, the reflected light cannot completely emit beautiful pearl rainbows and variegated light effects. In the drying process of the printed ink layer, the ink layer volume should have a large shrinkage force, and the shrinkage force and the self-gravity effect of the flake powder particles make the mica titanium pearlescent pigment powder be compressed, and it will tend to be compressed due to compression. parallel. For instance, pearlescent effects produced by the multi-level parallel arrangement in the pearlescent ink printing layer are very ideal, which is closely related to many factors such as the specific gravity, viscosity, and the like of the color paste, the coating, and the ink. Therefore, the directional arrangement of flaky pearlescent pigments is a very important aspect of measuring the pearlescent effect of the ink. A poor orientation will reduce the brightness and variability of the ink. The more the flake pigments can be aligned parallel to the substrate, The better the pearlescent effect of the pigment, the addition of a certain amount of polyethylene wax dispersion to the ink can improve its orientation properties.
2. Selection of Pearlescent Pigment Diameter in Ink Manufacturing
The choice of flake pigments should grasp the relationship between the flake size and the flicker effect: when the flake diameter is large, the spacing of the flicker sources (the distance between the flake and the flake) is large, the flicker effect is dispersed, and the larger the flake diameter is, the The more chance of multiple reflections and refractions of the light, the stronger the intensity of the flash; if the diameter of the film is small, the distance between the flash sources will be small, the flash effect will be concentrated, the chance of repeated reflections and refraction will be less, and the flash intensity will be weaker. . In addition to the relationship between the size of the film and the light, it is also related to the state of the pigment in the ink. Generally, the smaller the film diameter is, the easier it is to condense, and it is easier to settle in the connection material; the smaller the aspect ratio of the particles (the previously mentioned film diameter The thickness ratio is preferably about 200, and the material that satisfies this condition is very rare.) The more easily it is suspended in the binder. When inks are formulated, thickening agents may be added to prevent settling or pre-wetting of the pigments and redispersion in the vehicle to avoid agglomeration or settling. As the titanium mica pearlescent pigment has a good dispersion ability, it creates superior conditions for the manufacturer of the ink. In the low viscosity ink medium, good dispersion effect can be obtained only by low-speed stirring. You can avoid the use of three-roller machines, high-speed mixers, or ball mills in other ink manufacturing because they can cause the mica titanium pearlescent pigment particles to be broken and lose their luster. Even if the media (with good transparency) needs the above apparatus to be dispersed, it is recommended that the mica pearlescent pigment be added thereto after the final stage of the ink production process.
Second, the effect of screen printing process on pearl effect of printed products
Pearl ink screen printing process requirements are also different from other ink printing. In order to match the printing process with the ink printing performance, when the pigment particle size of the pearlescent ink is large, it will have a multi-faceted reflection property, and will form a very uniform and strong diffusion, resulting in a good pearl luster. However, special attention should be paid when selecting the number of screen meshes. The aperture of the screen is related to the particle size of the pearlescent pigment particles used in the ink, so that the ink can be printed on the substrate through the printing plate without being printed on the substrate. In the case of blocking mesh on the plate, it is generally required that the screen aperture be 1.5 to 2.5 times larger than the largest particle of the pigment, and it is better that the larger the mesh is, the better, because the mesh with a low mesh number will affect the accuracy of the pattern and print out. The image will be too rough. For this reason, the number of meshes used should be suitable. Manufacturers of pearlescent inks should indicate the pearlescent pigment particle size in the ink product packaging, which is convenient for users to use for reference. It is obtained from the experiment that inks prepared from pearlescent pigments with a particle size of 20 to 180 μm should be selected from 40 to 60 mesh. /in screen, can print some products with low precision. If the pearlescent particle size of 5 ~ 100μm pigment ink can be used 60 ~ 100 mesh / in screen, you can print some of the more sophisticated prints.
All in all, mica titanium pearlescent pigment is a new concept of optical color pigments, due to the diversity of substrates and processes, determines the diversity of pigments, it is a platform for color pigments, has a broad space for development, will certainly follow In-depth research, continue to reduce production costs, for the near future, the widespread application of mica titanium pearlescent pigments to create a broader road to give users the choice and use of products to create more convenience.
Reprinted from: Ink Information