PVA optical film, also known as polyvinyl alcohol optical film, is the core material of polarizer. PVA optical film is a polarizing film, which is made of PVA resin, plasticizer, antioxidant and other trace additives dissolved in water, and then cast and dried by an extruder. PVA optical film is the basic material for the manufacture of polarizers, and its performance directly determines the quality of polarizers. According to industry information network data, the cost of PVA optical film accounts for about 12% of the total cost of polarizers. Its terminal downstream mainly includes computers, mobile phones, tablets, and display panels.