Discussion on the application of the hottest nano

  • Detail

Discussion on the application of nanotechnology in ink

Nanotechnology (1 nm = one billionth of a meter of good news in the new material industry) is a high-tech that was born and rose rapidly in the late 1980s. Its basic meaning is to understand and transform nature within the nano size (i.e. 0.nm), and to create new substances through direct operation and arrangement of atomic and molecular motion laws and characteristics. This means that extremely pure materials and colorful new products can be produced. Nowadays, nanotechnology mainly includes nano physics, nano chemistry, nano materials, nano biology, nano processing, nanomechanics, etc

I. characteristics of nanotechnology

"nano meter" is a unit of measurement. One nanometer is only about 45 atoms long. After the invention of the scanning tunneling microscope in 1981, a molecular world with a length of 0.1 to 100 nm was born, with the goal of reconstructing products with specific functions directly from atoms or molecules. Therefore, nanotechnology is actually a technology that uses single atom and molecular range materials

nano structured materials are called nano materials for short, which means that their grain size is between 0 Between nanometers. Research shows that when small particles enter the nanometer order of magnitude, they have quantum size effect, small size effect, surface effect and macroscopic quantum tunneling effect. Nanoparticles have large specific surface area, surface atomic number and surface energy, and the surface tension increases sharply with the decrease of particle size, resulting in the thermal, magnetic, photosensitive properties and surface stability of nanoparticles different from normal particles

because the size of nanoscale particles is close to the wavelength of light, and it has the special effect of large surface, its characteristics, such as melting point, magnetism, optics, heat conduction, conductivity, etc., are often different from those of the material in the overall state. John Hart, general manager of "nano" PM, said that materials have certain uniqueness. When the material scale is small to a certain extent, it must use quantum mechanics to replace the traditional mechanics to describe its behavior. When the particle size of powder is reduced from 10 microns to 10 nanometers in the competition of product development, performance, quality, reliability, service, etc., although its particle size is changed to 1000 times, But when converted into volume, it will be 109 times larger, so there will be a significant difference between the two behaviors

the reason why nanoparticles are different from bulk materials is that their surface area is relatively increased, that is, the surface of ultrafine particles is covered with ladder like structures, which represent unstable atoms with high surface energy. Such atoms are easily adsorbed and bonded with foreign atoms, and at the same time, due to the reduction of particle size, they provide large surface active atoms. The particle size of nanoparticles is smaller than the length of light wave, so it will have complex interaction with incident light. Under appropriate evaporation and deposition conditions, metals can obtain black metal ultrafine particles that are easy to absorb light, which is called metal black, which is in sharp contrast to the high reflectivity and gloss surface of metals when they are formed in vacuum coating. Nano materials can be used as infrared sensor materials because of their high light absorption. The broad scope of nanotechnology can include nano material technology and nano processing technology. Among them, nano material technology focuses on material production (ultra-fine powder, coating, etc.) and performance testing technology (chemical composition, microstructure, surface morphology, physical, chemical, electrical, magnetic, thermal and optical properties). Nano machining technology includes precision machining technology (energy beam machining, etc.) and scanning probe technology

second, the application of nanotechnology in ink

(1) from the perspective of ink fineness and purity

the quality of ink fineness and purity is very sensitive to the impact of printing quality. To print high-quality products, we must have ink with high fineness and purity as a guarantee. Therefore, improving the purity and fineness of ink is also an important part of the study of new ink. Whether in anti-counterfeiting printing, it has adopted many industry-leading innovative technologies or ordinary printing, and whether it is offset printing machine, flexo printing machine, gravure printing machine, it is basically the same. The fineness of ink refers to the size of pigment (including filler) particles in ink and the uniformity of pigment and filler distribution in binder. Therefore, the fineness of ink not only reflects the quality of printing, but also affects the printing plate's printing resistance. It is known from the actual operation that the spot printing or field layout of color printing products contains small anti white words and lines, which is easy to cause the quality failure of blocking and dirty during the printing process. If you do not carefully check and analyze it, you may fall into the wrong operation zone, thinking that the ink consistency is inappropriate, the viscosity is too large, the ink volume is too large or the pressure is too large, and blindly make some wrong adjustments. As everyone knows, the real reason is that the ink fineness is not good, that is, the ink particles are too thick. The fineness of ink is directly related to the properties of pigments and fillers and the size of particles. Generally speaking, the ink made of inorganic pigments (excluding carbon black) has poor fineness and coarser particles, which is closely related to the rolling operation of the ink. The more times the ink is ground in the rolling process, the more uniform it will appear, the larger the contact surface between the pigment particles and the binder will be, the finer the ink particles will be, and the better and more stable its printing performance will be. It is obvious that the fineness of ink is closely related to the printing quality. For example, taking dot printing as an example, there are many high-profile and middle tone dots on the layout. If the proportion of ink particles and dot area is close, it is easy to make dots empty or fuzz, and even the printing disadvantage of weak dots appears. Therefore, the higher the fineness of ink, the clearer and fuller the dots on the printed matter are. In addition, the better the fineness of the ink, the greater its concentration, the stronger the color rendering power, and the higher the printing quality of the product. The fineness of the ink is not good, the particles of the pigment are coarse, and the friction coefficient is large during the printing process, so the printing plate's printing resistance is low. And the ink with coarse particles is also prone to paste and ink accumulation during printing, as well as uneven ink transmission and distribution. The fineness of the ink can generally be judged by visual observation, that is, if the surface scraped by the ink knife is smooth. Uniform visual effect indicates that the ink has good fineness. If there is a small or granular rough layer on the scraped surface, the fineness of the ink on the surface is poor. In addition, you can also use coated paper to dip a little ink layer, and then use another piece of paper to polish the ink layer, until the ink layer is very thin, it is still very shiny, indicating that the ink fineness is good. If there are traces of ink layer, it is obvious that the ink is caused by coarse particles of pigment and filler, indicating that the ink fineness is not good enough. Of course, the above is only based on experience, and the accuracy of discrimination has certain limitations. To realize standardized and informative judgment, only by relying on the fineness meter to measure the size of pigment particles, can the fineness of ink be detected more accurately. The specific method of measuring the fineness of the ink with the fineness meter is to dilute the sample ink to a certain extent, place it in the deepest part of the fineness meter, and then move the scraper along the groove (keep a constant speed) to the shallowest place. The particle size of the ink can be seen at the scales on both sides of the groove. In addition, you can also use a microscope to observe the size of ink pigment particles

(to be continued)

Copyright © 2011 JIN SHI