Optical film is different from ordinary protective film or tape. It has uniform thickness, and the surface requires dust-free and few crystal points. This puts forward higher requirements for coating technology and requires more uniform film thickness. So what are the coating technology of optical film, let electronic material supplier with 10 years experience in optical PET film explain for you:
Optical film coating has traditionally been prepared by vacuum evaporation, chemical deposition, plasma polymerization, etc. These methods are difficult to achieve large-scale production of roll film substrates; in modern coating processes, common coating methods include dip coating, Roll coating, slope extrusion coating, curtain coating, etc. These coating methods are suitable for different performance materials and coating thicknesses, and have their own advantages and disadvantages. The coating amount of dip coating is not easy to control and is greatly affected by the characteristics and temperature of the material; the thickness of the coating applied by roller coating is easy to control, the coating amount is relatively easy to control and the uniformity is good, but it is greatly affected by the characteristics of the material The viscosity range of the adaptable material is narrow; although the coating amount of the slope extrusion coating is easy to control, the viscosity range of the adaptable material is narrow, the coating amount is too small to be easy to apply, and it cannot be applied to the edges, resulting in waste of the substrate; Curtain coating is a predictive coating method. It is easy to operate. The thickness of the coating in the longitudinal and transverse directions is very uniform. The coating has no scratches, streaks, orange peel, but the curtain is easily affected by factors such as vehicle speed. Therefore, stable curtain is a big problem.