POLYVINYL ALCOHOL-TYPE POLYMER FILM AND METHOD FOR PRODUCING SAME

摘要

[Problem] To provide: a PVA-type polymer film which enables the production of a polarizing film having a high absorption of light with a long wavelength region and having a high polarization degree; and a method for producing the PVA-type polymer film. [Solution] A PVA-type polymer film having a crystal long period of 14.5 to 16.0 nm in water; and a PVA-type polymer film production method comprising forming a PVA-type polymer film using a film formation apparatus equipped with multiple drying rolls of which rotation axes are parallel to each other and a heat-treatment roll, wherein the PVA-type polymer film is dried in such a manner that the value of T1->2 represented by formula (I) becomes 60 to 75. T1->2 = {T1×(40-V1)+T2×(V1-V2)}/(40-V2) (I) (In the formula, T1 represents the temperature (°C) of the surface of a first drying roll; V1 represents the volatile fraction (mass%; V1 falls within the range from 10 to 30) of the film upon the delamination of the film from the first drying roll; T2 represents the average value (°C) of the temperatures of the surfaces of all of the second drying roll to the final drying roll; and V2 represents the volatile fraction (mass%) of the film upon the delamination of the film from the final drying roll.)