| 摘要 |
PURPOSE:To produce stably the titled film having a broad width by incorporating an inorg. salt to a solution capable of giving durability, when treating the polarizing film of the film made of polyvinyl alcohol or its derivative which absorbs and orientates polarizing element, with the solution capable of giving durability to the polarizing film. CONSTITUTION:The inorg. salt is added to the solution capable of giving durability, when the polarizing film of the film composed of the polyvinylalcohol or its derivative which adsorbs and orientates the polarizing element such as iodine or a dichroic dyestuff, is treated with the prescribed solution. By incorporating the inorg. salt to the prescribed solution, the shrinking of the titled film in a transverse direction (neckin) is reduced, thereby obtaining the titled film having the broad width. The temperature of treating for give durability to the titled film is not specified, and is preferably 50-80 deg.C. As the used inorg. salt, a sulfate of alkali metal or alkaline earth metal, etc., are generally used, and sodium sulfate is the most preferable.
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