Editor's Note: Nanoscience and technology are high-tech technologies that emerged in the late 1980s and have rapidly emerged. Its basic implication is to understand and transform nature in the nanometer dimension (ie, 0.1 to 100nm), through direct manipulation and arrangement of atomic and molecular movements. Laws and characteristics, technical methods for creating new substances. This means that people can produce extremely pure materials and rich new products.
First, the characteristics of nanotechnology "Nano" is the English translation of namometer, 1 nanometer is one billionth of a meter, only about 45 atoms are bunched up so long, nanostructures usually refer to tiny structures with sizes below 100 nanometers. At present, nanotechnology research is mainly in the aspect of nanomaterials, and nanomaterials are substances whose grain size is in the range of 1 to 100 nanometers. Studies have shown that when the material particles enter the nano-particles, they themselves have the characteristics of quantum size effect, small size effect, surface effect, and macroscopic quantum tunneling effect. Since the size of a nanoparticle is already close to the wavelength of light, coupled with the special effect of having a large surface, its characteristics such as melting point, magnetic, optical, thermal, and electrical conductivity are often different from the behavior of the substance in its overall state. characteristic.
Second, the application of nanotechnology in the printing field 1. The nano-paper traditional paper uses coarser fibers such as trees, bamboo, and hemp, and the particles of paint and filling materials are relatively large. Therefore, ordinary paper has the disadvantages of being afraid of water, fear of moisture, and the like. Although offset printing paper and electrostatic copying paper are waterproof, Anti-moisture and other functions, but inconvenient to write. Nanotechnology has become more widely used in the paper industry. At present, wood fibers can only be processed to the micron (100-1000 nm) level. Due to the relatively coarse cell diameter of wood, wood nanotechnology can change the cell structure of the wood and control the cell growth, which may change the characteristics of the wood. When the wood is processed to the nano level, the original cell structure of the wood will be destroyed and the structure of the fibrous structure will change. The cellulose, hemicellulose and lignin may be separated mechanically during the processing so that the paddle rate can be greatly improved and Reducing environmental pollution caused by the papermaking industry.
In papermaking coatings, the use of nano-calcium carbonate in coated white paperboard coatings can effectively improve the performance of whiteboard. The addition of nano-calcium carbonate is beneficial to the improvement of several important performance indexes of the coating, such as IGT value, K&N ink absorption, smoothness and the like.
At present, the use of nanotechnology in the paper industry has begun to enter practical production. For example: Henan Yinge Co., Ltd. and the Nanoscience and Technology Research Institute of Huazhong Normal University adopt the most advanced nanotechnology in the world and perform nanoscale structural layer preparation on plain paper. Waterproof nano paper. In addition to maintaining the original writing and copying functions of the paper, it also has the special properties of super-hydrophobicity and moisture-proof that ordinary paper does not have, and it can increase the strength of the printing surface and reduce the rate of expansion and contraction.
2. Nano ink ink fineness and print quality are closely related. The better the fineness of the ink, the stronger the tinting strength, the clearer and fuller the dots of the printed matter. Recently, the nano-scale transparent iron oxide pigments that have been recently rated as national key new products by the Ministry of Science and Technology have been successfully developed. Nano-metal particles can absorb all light waves and make themselves black, while also scattering light. Adding nano-metal particles to the black ink increases the purity and density of the black ink. In addition, after the chemical modification of the surface of the semiconductor nanoparticle, the medium around the particle can strongly affect its optical characteristics, and the red shift or blue shift occurs in the absorption spectrum. If they are added to yellow and cyan inks to make nano inks, they can increase the purity of yellow ink and cyan ink and make the print layer more abundant. Nowadays, with the aid of high technology, various components (inks, pigments, fillers, etc.) in inks can be made into nano-scale raw materials. Because of their high fineness and good flow and lubricity, they can achieve high hiding power with low pigment content. Effect. If used in UV inks, it can speed up the curing speed and eliminate shrinkage and wrinkling of the ink film. Nano-scale carbon ink is conductive and has a good shielding effect on electrostatics. If ink is added, it can be made into conductive ink. In the conductive ink will be made of Ag, such as Ag instead of micron Ag, can save 50% of Ag Powder, this ink can be directly printed on the ceramic and metal, the ink film is thin and evenly smooth; If Cu, Ni Material made of 0.1 ~ 1μm ultrafine particles, can replace palladium and silver and other precious metals conductive. Combining nanometers with anti-counterfeiting technology will open up another vast area of ​​security ink.
Some nanopowder particles can emit light by themselves, such as "-N≡N-" nanoparticles, which can emit light in the dark for 12 to 24 hours in a few minutes. The luminous intensity and maintenance time are 30 times that of traditional fluorescent materials. More than doubled, and the material itself is non-toxic, harmless and does not contain any radioactive elements. Because the nanoparticles have good surface wettability, they are adsorbed on the surface of the pigment particles of the ink, which can greatly improve the oleophilicity and wettability of the ink.
3. Nano-ceramic anilox roller The so-called nano-ceramic, refers to the microstructure of the material phase has a nano-scale ceramic material, so that the strength of the material, toughness and super-plastic greatly improved. We know that laser-engraved ceramic anilox rolls are currently used very much in flexographic printing, and it is considered to be the key to improving the quality of flexographic printing. Narrow-web flexographic printing presses and UV ink flexographic presses have almost all used ceramic anilox rolls. From the perspective of flexo printing, ceramic anilox rollers will eventually eliminate all metal anilox rollers. Cahn, a well-known British material expert, pointed out that nano-ceramics are a strategic way to solve ceramic brittleness. For the flexographic printing anilox roll, when the anilox roll is processed by the plasma thermal spraying process, a high-quality ceramic coating is required to be sprayed on the surface of the substrate. The coating hardness range must be HV300 to 1300, and the general porosity. Must be less than 1%. For anilox rolls above 1200 lines, the porosity must be less than 0.5%, and the coating structure should be uniform, high hardness, high density, etc., while the nano-properties in nano-ceramics can improve the ceramic Hardness, toughness, wear resistance, which laid the foundation for the excellent engraved anilox roller.
In short, nanotechnology, as a rapidly developing new technology in recent years, will continue to develop in the depth and breadth of its applications in the field of printing.
4. Nano-packaging materials Nano-technology enables nano-synthesis, nano-adding, and nano-modification of packaging products, enabling them to have new packaging features such as nano-structure and scale. The most studied in recent years is polymer-based nanocomposites. Such as nano-composite plastic packaging materials, compared with traditional plastic packaging materials, plasticity, wear resistance, hard strength and other properties have improved significantly. In addition, polyester PET and PBT nano-plastics also have the characteristics of flame-retardant, relatively pure barrier properties, which can replace the higher-priced PBT resin and meet the requirements of packaged foods.