Nano-printing ink characteristics and application

With the continuous improvement of the printing quality requirements, higher requirements have been put forward for inks. With the rapid development of science and technology, various types of inks are constantly appearing in the fields of ordinary printing, special printing, and security printing. They not only require excellent quality of printed products, but also meet various special needs such as environmental protection and anti-counterfeiting. As a result, the emergence of such as magnetic ink, fluorescent ink, photo-induced changeable ink, temperature-varying ink, etc., has brought the development of the printing industry to a new height. Below, we briefly introduce the characteristics and uses of several high-tech specialty inks.

Nano ink

(1) From the ink fineness and purity

We know that the fineness and purity of the ink have a great influence on the quality of the printed matter. To print high-quality products, we must have a fine, high-grade ink as a guarantee. The fineness of ink refers to the size of the pigment (including filler) particles in the ink and the uniformity of the pigment and filling material distributed in the binder. It reflects both the quality of the printed product and the printing plate. rate. The practice of the process shows that the color printing products use net printing or field layout to contain small Yin and Yin lines. During the printing process, stencils, layout infections, and quality failures are likely to occur. If they are not carefully checked and analyzed, they may be caught in operational errors. The ink thickness was uncomfortable, the viscosity was too large, the amount of ink was too large or the pressure was too high and blind adjustments were made blindly. Who knows is caused by the fineness of the ink. The fineness of the ink is directly related to the nature of the pigments, fillers, and the size of the pellets. In general, inks made with inorganic pigments (excluding carbon black) have coarser particles. This has a lot to do with the rolling process of the ink. The more the ink is ground during the rolling process, the more uniform it becomes, the greater the contact surface between the pigment particles and the binder, the finer the ink particles, and the better and more stable the printing performance. In the case of printed anilox prints, there are no shortages of high- and mid-tone 1 to 4 percent screens on the layout. If the ratio of ink particles to the dot area is relatively close, then it is easy to make the dots empty or spread, and even the dots are not clean. The printing defects. Therefore, the higher the fineness of the ink, the clearer and fuller the dots on the print.

The fineness of the ink is low, the coarse particles of the pigment, the friction coefficient during the printing process are large, and the imprint resistance rate of the printing plate is low, and the phenomenon of stencil and ink deposition and the inconsistent transmission of ink and ink are easily generated during printing. The fineness of the ink can generally be judged by naked eye observation, that is, the surface scraped by the ink knife shows a smooth and uniform visual effect, indicating that the fineness of the ink is good; for example, a small scraped surface appears. A coarse or granular roughened layer has poor fineness of the ink. In addition, it is also possible to use a small amount of ink layer on the coated paper, and then use another layer of paper to grind the ink layer until the ink layer is dragged to a very thin, which means that the ink is fine. If traces of ink appear, it is clear that the traces are caused by ink pigments, filler coarse particles. Of course, the above is judged only by experience, and the accuracy of discrimination has certain limitations. To achieve standardized, data-based judgment, only rely on fineness meter to determine the size of pigment particles in order to more accurately detect the fineness of the ink. The method is: dilute the sample ink to a certain degree, place it in the depth of the fineness meter, and then use the scraper to treat the groove movement (to maintain a constant speed) to the shallowest place, and the ink can be seen on the scale marks on both sides of the groove. The size of the particles can also be used microscopically to observe the size of the ink pigment particles.

(2) Characteristics of Nano Ink

Nanotechnology is a new science and technology. The nanometer is a length unit, which is 9m~10m. The research object of this technology is mainly nanomaterials. Nanomaterials have now begun to penetrate various fields. As the nano-metal particles can absorb all the light waves and make themselves appear black, they also scatter light. Therefore, by using these characteristics, nano-metal particles can be added to the black ink, and the nano ink can be manufactured to increase its purity and density. In addition, due to the existence of significant quantum size effects and surface effects, semiconducting nanoparticles exhibit a certain degree of absorption of light.

Studies have shown that after chemical modification of the surface of the nano-semiconductor particles, the surrounding medium of the particles can strongly affect the optical properties, showing a red-shift or blue-shift of the absorption spectrum. Experiments show that the absorption edge of cds nanoparticles has obvious blue shift, and the absorption edge of tio2 nanoparticles has a large red shift. Accordingly, if they are added to yellow and cyan inks to make nano inks, their purity can be improved. The use of nano-inks with specific nano-particles to reproduce printed color prints will result in a richer hierarchy, a clearer tone, and a greater ability to express the details of the image.

Nowadays, with the help of high technology, various components in inks (such as resins, pigments, fillers, etc.) can be made into nano-scale raw materials. In this way, due to its high degree of fineness and fine flow and lubricity, it can achieve better dispersion and suspension, stability, low pigment content, high hiding power, good gloss, fine resin particle size, continuous and uniform film formation, Thin film, print images more clearly. If used in uv inks, the curing speed can be accelerated, and shrinkage and wrinkling of the ink film can be eliminated due to the fine and uniform dispersion of the filler. In the glass-ceramic ink, if the inorganic material is made into nano-scale fineness, it will save a lot of raw materials and print more refined and more beautiful high-quality images. This brings a huge change to the ink manufacturing industry, so that instead of relying on chemical pigments, it chooses the appropriate volume of nanoparticles to present different colors. Because there are substances in the nanoscale, the particle size of the different colors are different, or different materials of different colors, such as tio2, sio2 in the nanoparticles are white, cr2o3 is green, fe2o3 is brown, and inorganic nanomaterials such as nano-al2o3 have very Good fluidity, if added to the ink can greatly improve the wear resistance of the ink film. Nano-scale carbon ink is conductive, has a good shielding effect on static electricity, to prevent the signal from external static electricity interference, if it is added to the ink can be made into conductive ink, such as large-capacity integrated circuits, modern contact panel switches, etc. . In addition, in the conductive ink, such as the ag made of nano-grade instead of micro-ag, can save 50% ag powder, this conductive ink can be directly printed on the ceramic and metal, ink film thin and uniform smooth, very good performance it is good. If the cu, ni material is made of ultrafine particles of 0.1μm ~ 1μm, it can replace palladium and silver and other precious metals conductive. Therefore, the combination of nanotechnology and anti-counterfeiting technology will open up another broad field of security ink.

In addition, some nanopowder particles themselves have luminescent groups and may emit light themselves, such as "-n≡n-" nanoparticles. Prints printed with inks containing this kind of particles can be recognized by human eyes without external light source irradiation, and can also be used for anti-counterfeit printing; they can be used for outdoor large-scale advertising printing or nighttime printing. Photographic prints that are read will no longer require external light sources, which will not only save energy, but also greatly facilitate users.

Because nanoparticles have good surface wetting properties, they are adsorbed on the surface of the pigment particles in the ink, which can greatly improve the ink's lipophilicity and wettability, and can ensure the stability of the entire ink dispersion system. Therefore, nanoparticles are added with nanoparticles. Nano ink printing performance is greatly improved. With the further development of nanomaterial technology, it is believed that more nanomaterials with different characteristics will be recognized and used by people.

In electrostatic copying, magnetic nanopowders are used instead of non-magnetic toners, which are widely used today, to eliminate the need to add ferromagnetic particles as a carrier in non-magnetic toners and to make a single-component copying developer. Raw materials and improve copy quality.

As for the source of nanomaterials. In fact, there are many ways to obtain nanomaterials, such as high-temperature sintering (such as sintering technology of carbon nanotubes), precipitation method, high-temperature dissolution method, chemical vapor condensation method, or modern plasma energy polymerization method.