The development of science and technology makes nanotechnology waves in the ink field

With the continuous development of science and technology, "nano" and the "nanotechnology" and "nanomaterials" derived from it are frequently appearing in everyday life. The impact that nanometers bring on us and technological progress Has affected the industrial sector to a great extent, and the nanotechnology caused by it is applied in many industries such as rubber, plastics, glass steel, coatings, ceramics, adhesives, sealants, polishing slurries, and medicine, metallurgy, printing, etc. widely.

Since 1994, the United States of America's XMX company in Massachusetts has successfully applied for patents for the manufacture of nano-scale uniform nano-particles for inks, nanotechnology has created waves in the ink field. The ink is a stable, coarse dispersion system composed of a pigment as a dispersed phase and a binder as a continuous phase. So, what is nano-ink? We add nano-particles to the ink, or make the ink-making raw materials (such as resins, pigments, fillers, binders, etc.) into nanometer size, so the ink produced is nano-ink. . Nano ink itself has many advantages that ordinary inks cannot match, bringing great changes to the ink world.

Let's look at the advantages of using ink made from nano-sized raw materials. We know that many common inks require the addition of surfactants during the manufacturing process to reduce the surface tension of the binder and increase the affinity of the entire system. The nanoparticles themselves have very good surface wettability. They adsorb on the surface of the pigment particles in the ink, so that the oleophilic and wettability of the ink is improved, and the solid and liquid structures of the ink are stabilized, so the addition of Nanoparticle inks can greatly improve their printability.

As we all know, ink fineness is an important indicator to measure the quality of ink, process practice shows that: high fineness ink color strength, high gloss, high light part is complete and the entire print is clear and full; low fineness ink will cause a lot of printing Failures, such as lithography, can cause stencils, heaps of ink, stencils, etc.; solvent-based inks can cause stencils and ink settling. In general, the higher the printing cable, the higher the fineness of the ink. In the printing process, we often encounter high-profile 1 to 40% dots in the layout. At this time, the advantages of nano inks will be at a glance. Since all kinds of raw materials in nano inks are made of nano-sized particles, their fluidity and wettability are greatly increased compared with ordinary inks, and all kinds of particles are uniformly dispersed and suspended, resulting in extremely high ink fineness. To a great extent, the above-mentioned conventional ink cannot be overcome because it is encountered.

High-fineness nano inks also have a significant advantage, that is, to enhance the printing plate's resistance to printing force, we all know that the printing plate is directly in contact with the ink, the printing plate is mostly multilayer metal with low strength The composition of the plate, if the ink particles are coarse, the friction coefficient must be large under the effect of the printing roller, so that it is very easy to abrade the plate. Causes damage to the plate. The nano-particles with evenly-sized particles will not or will reduce the occurrence of this situation.

Then, what are the advantages of adding nanoparticles to the ink? The nanoparticles added to the ink can be metal particles and their oxide particles, or they can be non-metallic particles; they can be organic particles or inorganic particles. Different particles add different ink characteristics. For example, nano-metal particles, which absorb light waves by themselves are different from the general materials, they can absorb all kinds of wavelengths of light to make themselves appear black, but also have a scattering effect on light, therefore, adding metal nanoparticles The ink has a higher purity and density. As another example, CdS nanoparticles and TiO2 nanoparticles, which belong to semi-conductor particles, after the surface has been chemically modified, the medium around the particles can strongly affect the chemical properties. The former shows that there is a clear blue shift in the light absorption edge, while the latter shows a clear red shift in the light absorption edge. Therefore, adding them to the yellow ink and the cyan ink to form a nano ink can enhance the light absorption. The expressiveness of yellow and cyan color makes the print layer richer and the tone more vivid, which greatly enhances the detail expressiveness of the image. There are also substances that, when they are on the nanometer scale, have different colors themselves. For example, Cr2O3 is green and Fe2O3 is brown. Therefore, we do not rely solely on chemical pigments to express the color of the ink. Instead, we can use Specific nano-particles to replace.

Also, for example, particles such as SiO2 and TiO2 exhibit strong UV resistance and catalytic resistance at the nanometer level, which makes the nano inks to which they are added have significantly increased aging resistance and sun resistance, and due to their own Very small, with a very large specific surface area (50% particle surface area percentage 50%, 2nm particle surface area percentage increased to 80%), the network structure can be quickly formed when the ink is dry, increasing the ink strength and finish. Some of the microparticles themselves have luminescent groups, and they can continue to emit light after receiving light for a short period of time, such as [-N≡N-] nanoparticles, the luminescent time and luminous intensity of the ink added with the microparticles. All of them are more than 30 times of ordinary traditional fluorescent inks, and the materials themselves are non-toxic, harmless, and non-polluting. It is convenient and practical for prints to be read at night, so it is a very good special ink.
Since the particles themselves have different properties, the properties of the ink produced after the addition are also different. The addition of conductive particles can shield static electricity to make conductive ink; adding particles with good fluidity can improve the wear resistance of the film. Nowadays, nano inks are used in security printing. Its unique mechanism can not only achieve good printing results, but also anti-counterfeiting effect and anti-counterfeiting performance are self-evident. Therefore, we can choose the required nano inks for production according to actual requirements, so that the printed products have unique properties.

Now that nano inks have been developed for more than a decade, the advantages of nano inks are obvious to all. However, nano inks are not yet very popular. This is because there are still some technical bottlenecks in the manufacturing process of nano inks, such as nano-dispersion technology. This involves two problems, namely, crushing particles to the nano level and dispersing nano-sized ions. Ball mills used to make traditional inks are difficult to grind raw materials to the nanometer level, and even if they meet the requirements of the nanometer level,

Due to the tiny particles and the extremely high surface area, the particles easily aggregate to form large particles. Therefore, we must develop new grinding and dispersing technologies to meet the requirements of raw material size and research new nanomolecular coating technology to prevent its agglomeration.

Although there are many obstacles along the way, due to the irreplaceable advantages of nano inks, we will continue to explore on this road. We believe that in the future ink industry, nano inks will surely be the mainstream of leadership development.

Source: Guangdong Printing Author: European Dingjun