Progress in application of precision coating technology

　　 Application progress of precision coating technology precision coating is an important processing technology to change and improve the surface characteristics of materials. with the continuous development of science and technology, precision coating has become an indispensable technical means for the research and development of many important functional materials. In particular, precision coating technology can meet the special requirements of some coatings, thereby increasing the added value of materials and expanding their application scope.

　　 Multilayer flow extrusion coating and curtain coating are typical representatives of precision coating technology. It is the development and application of multi-layer slope flow extrusion coating technology that has greatly improved the performance of the multi-layer structure of color photosensitive materials and realized industrial production. It can be said that if there is no multi-layer high-speed extrusion coating technology, the total thickness of more than 10 layers is only 20 μ It is unimaginable to industrialize the production of color films of about m. At present, although the photographic material industry is on the decline, extrusion coating and curtain coating technologies are still being promoted and applied in light industry papermaking, membrane processing, packaging materials and other industries.
In recent years, flat panel display industry and some new photoelectric products have developed rapidly. The coating of these products is often required to be thinner and more uniform, which puts forward new requirements for precision coating technology. For example, the coating thickness of the anti reflective film used in the LCD is only a few to 100NM; The coating of new rechargeable lithium battery electrode shall be strip coating or intermittent block coating. Multilayer extrusion coating and curtain coating obviously can not fully meet the requirements in this regard. Traditionally, optical coatings are prepared by vacuum evaporation, chemical deposition, plasma polymerization and other methods, that is, solid components are evaporated and deposited on specific substrates under vacuum conditions.
Due to the need of vacuum closed operating environment, it is difficult to achieve low-cost, efficient volume to volume production. Although the rotary coating method can also obtain uniform and thin coating effect, it is limited by the coating area and coating efficiency, especially the utilization rate of its coating solution is only about 5%, which causes huge waste and is difficult to achieve low-cost industrial production. Therefore, it is an inevitable choice to seek new precision coating technologies that adapt to low cost, high quality and mass production to meet the needs of market competition.
For example, the transparent electrode conductive layer Indium Tin Oxide (ITO) in many optoelectronic products is prepared by sputtering. At the end of 2008, Hitachi announced the use of precision coating technology to produce transparent ITO conductive films. The company used the experience of hydrothermal preparation of iron oxide magnetic powder to prepare nano ITO particles, and then prepared ITO coating solution by dispersion method. Then ITO plating solution is coated on PET substrate by micro intaglio roller coating method, and transparent ITO conductive film is obtained after drying. On the other hand, the process of preparing transparent conductive film by organic conductive polymer solution coating instead of ITO film has begun to get more and more applications.