Polarizer PVA film is one of the key upstream materials in the electronic display industry. Its essence is a composite film, which is mainly composed of PVA film, TAC film, pressure sensitive adhesive, release film and protective film. Among them, the PVA film is the core material of the polarizer to realize the polarization function, which determines the polarizing performance, transmittance, color and other key optical indicators of the polarizer.
Polyvinyl alcohol (PVA) film is mainly composed of light atoms such as carbon, hydrogen and oxygen. It has high transparency and high ductility, as well as good iodine adsorption and film-forming characteristics. It is the core raw material of polarizers.
The PVA film can play a polarizing effect because it can adsorb bidirectional molecules, such as the most widely used iodine-based PVA film: The PVA molecular chain is disorderly distributed before the treatment, and the iodine molecules adsorbed on the PVA film are also disorderly. After the PVA film is stretched and oriented, the iodine molecules on it are also distributed in an orderly manner. The two-way absorption molecules that adsorb iodine are extended and aligned, so that the PVA film has the function of polarization, which determines the polarization performance, transmittance, color and other key optical indicators of the polarizer. .
The "Three-year Action Plan to Enhance the Core Competitiveness of Manufacturing Industry (2018-2020)" issued by the National Development and Reform Commission puts forward clear development goals for polarizers and supporting film materials, mainly including polarizers for TFT-LCD and supporting cellulose acetate ( TAC) film, polyvinyl alcohol (PVA) film, etc. The document pointed out that the degree of polarization can be customized and adjusted from 95% to 100% according to user needs, and the comprehensive performance can meet the needs of high-generation (6th generation and above) TFT liquid crystal displays; the light transmittance of the optical polyester base film for polarizers is greater than 88%, and the haze Less than 1%, the comprehensive performance meets the needs of polarizers; the scale of a single device reaches 10 million square meters per year. In particular, the domestic polarizer market is expected to reach 5.3 billion U.S. dollars in 2020, accounting for about 40% of the global market share.
Monopoly and leading situation: China's PVA film market is mainly monopolized by Japan's Kuraray, and Kuraray itself is one of the main suppliers of high-end PVA resin raw materials in the world. Kuraray’s monopoly in the field of PVA optical films benefits from its integrated production system, which can realize the integrated production of high-end PVA resins, PVA films for polarizers, and surface treatment of PVA films. According to Kuraray's data, Kuraray's PVA resin supply accounted for about 40% of the world as early as 2018, and the supply of PVA film for polarizers in particular accounted for 80% of the global supply. International leading companies: Kuraray, LG Chem, Samsung SDI, Nitto, Sumitomo Chem, etc.; Chinese companies: Wanwei Hi-tech, Sanli Spectrum, Dongfang Asahi Optoelectronics, Shengbo Optoelectronics, Shengbaolai.