| 摘要 |
PURPOSE:To efficiently obtain a polarizing film having high durability and high degree of polarization by adsorbing a dichromatic dye on a PVA film, impregnating metal ions and boric acid therein, stretching the film uniaxially and subjecting the film to a heating treatment. CONSTITUTION:The PVA film dyed with the dichromatic dye is immersed in an aq. soln. contg. the metal ions and boric acid and is thereby impregnated wit the metal ions and boric acid. The film is then stretched substantially uniaxially as it is or in the above-mentioned aq. soln. or separately prepd. water under mild heating conditions of room temp. or <=50 deg.C; thereafter, the film is subjected to the drying and heating treatment while the tense state is maintained. The polarizing film obtd. in such a manner has excellent optical characteristics and is enhanced in the heat resistance and moisture resistance.
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