| 摘要 |
PROBLEM TO BE SOLVED: To provide a polarizing film which is less changed in transmittance even at high temp., is highly durable and is high in transmittance and polarization degree by regulating the content of zinc of the polarizing film to a prescribed range. SOLUTION: This polarizing film is a polyvinyl alcohol(PVA) resin film subjected to dyeing with iodine and contains 0.04 to 0.5 wt.% zinc. Usually, PVA is used as the PVA resin and the degree of polymn. thereof is in a range of 1000 to 10000, more preferably in a range of 1500 to 5000. The saponifyed PVA resin is usually used. The degree of saponification thereof is usually a range of 85 to 100 mol.%, more preferably 98 to 100%. A method to be executed by previously incorporating zinc ions into a aq. boric acid soln. to be used at the time of the treatment to immersion into the aq. boric acid soln. is preferable as the method of incorporating the zinc into the film.
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