| 摘要 |
PURPOSE:To develop flaws which are hardly observable with naked eyes without damaging the material of a polarizing plate by bringing a prescribed solvent into contact with the surface of a triacetyl cellulose film for the polarizing plate subjected to an alkali hydrolysis treatment so that the flaws on the treated surface are developed. CONSTITUTION:The triacetyl cellulose film for the polarizing plate is immersed for about one minute into a heated (60 deg.C) aq. alkali soln. of 3N sodium hydroxide, etc. by which the film is subjected to the hydrolysis treatment. The treated film is immersed for about 10 seconds in a solvent selected from a methyl ethyl ketone, ethyl acetate, acetone and tetrahydrofuran and is then air-dried. As a result, the damaged part of the film is whitened and is made distinctively observable by naked eyes. |
