| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method of a polarizing film, which permits efficient production of a polarizing film that has a low content percentage of boron atoms and is environmentally friendly upon discarding can be efficiently produced while the film has excellent optical characteristics with a high transmittance and a high polarization degree, which permits production of a wide and thin polarizing film at a high stretch magnification and a high yield without requiring a large amount of boric acid, and thereby, which can contribute to cost reduction.SOLUTION: The production method of a polarizing film comprises dyeing and uniaxially stretching a polyvinyl alcohol-based polymer film. The uniaxial stretching is carried out in an aqueous solution containing boric acid by 0.1 to 2.0 mass%, at a stretching magnification of 7 times or more and 8 times or less; and the polyvinyl alcohol-based polymer film is prevented from being in contact with an aqueous solution containing boric acid at a concentration of over 2.0 mass%. The aqueous solution contains only boric acid and potassium iodide as components or does not contain a dicarboxylic acid. |
