Unlike ordinary protective films or tapes, optical films must be uniform in thickness, with a dust-free surface and fewer crystals, which puts higher demands on the coating technology and requires the film to be made more uniform in thickness.
Therefore, the precision coating process is also gradually developed and continuously improved. Optical film coating traditionally used vacuum evaporation, chemical deposition, plasma polymerization and other methods of preparation, these methods are difficult to achieve the mass production of rolled film substrates; in the modern coating process, the commonly used coating methods are dip coating, roller coating, slope flow extrusion coating, falling curtain coating. These coating methods are suitable for different properties of materials and coating thickness, and have their own advantages and disadvantages. Such as dip coating of the coating amount is not easy to control, by the characteristics of the material and the temperature is more affected; roller coating coating coating thickness is easy to control, the coating amount is easier to control, uniformity is better, but by the characteristics of the material has a greater impact on the viscosity of the material to adapt to the range of narrower; slope flow extrusion coating, although the amount of coating is easy to control, but to adapt to the range of the viscosity of the material is narrower, the amount of coating is not easy to coat when too small and can not be painted to the edge, resulting in a waste of substrate; drop curtain coating; drop curtain coating. Substrate waste; falling curtain coating is a pre-measurement coating method, its operation is simple, longitudinal and transverse coating thickness is very uniform, the coating has no scratches, stripes, orange peel, but the falling curtain is susceptible to the speed and other factors, therefore, stabilizing the falling curtain is a big problem. The thickness of the currently used coatings varies in a wide range, some of which are very thin, and the surface requires uniformity and smoothness. In order to improve the production capacity, the coating speed should be high, so some research institutes have begun to study micro-gravure roller coating and strip-seam coating.
Micro-gravure roller coating has the advantages of easy operation, wide range of coating volume, saving substrate, wide range of adaptability of substrate thickness, good coating appearance, smooth and glossy surface and so on. Strip-seam coating is a pre-measurement of the coating method, coating uniformity, can realize large size coating, ultra-thin layer coating. These two coating modes are new precision coating process technologies developed after the development of precision coating process technologies such as one-time multi-layer slope-flow extrusion coating and falling curtain coating, which are gradually applied in the preparation of flat panel displays, optoelectronic products, lithium batteries and other related products.
Micro-gravure coating method first proposed by Japan's Fuji, mainly coated with high-end functional films, in its anti-reflective film preparation process has been used in the micro-gravure coating method, others, such as Konica Minolta, Hitachi Maxell, etc., in the relevant products have also been used in the micro-gravure coating equipment. The slit coating method was also first developed and applied by Fuji in Japan. Fuji has prepared an anti-reflection film with a 4-layer structure, i.e., substrate/hard layer/medium-refractive-index layer/high-refractive-index layer/low-refractive-index layer, and preferred the slit coating method. Huang Shanghong has studied the cavity design of slit coating nozzle, discussed the role of each component of the slit coating nozzle, pointed out that the structure of the distribution chamber should make the pressure distribution reasonable, reduce the vortex, and fit with the slit, set up the sub-chamber as needed, so that the material in the coating nozzle of the same retention time, such as the design and manufacture of slit coating nozzle of the key factors. Micro-gravure coating system and slit coating system is a kind of precision coating system involving elastic fluid dynamics, which needs to be coated in the environment with high requirements of coating cleanliness, any dust and impurities will have an important impact on coating, and it is necessary to build new plants in accordance with the ISO standard of cleanliness, and to strictly implement the rules and regulations of cleanliness.

Room termperature curing polysilazane, pls check IOTA 9150, IOTA 9150A. 
High termperature curing polysilazane, pls check IOTA 9108, IOTA 9118.