| 摘要 |
PROBLEM TO BE SOLVED: To obtain a highly durable polarizing film having an excellent optical characteristic and with the lowering of the polarizability improved when allowed to stand under high temp. and high humidity by cleaning a PVA film having adsorbed a dichroic substance, drawn and oriented with an aq. saccharides soln. and then heat-treating the film. SOLUTION: A PVA film having adsorbed a clichroic substance, drawn and oriented is cleaned with an aq. saccharides soln. and then heat-treated. A boron compd. such as boric acid and borax is added to promote the adsorption of the dichroic substance on a base film. The PVA film thus obtained is cleaned with an aq. soln. of the saccharides capable of effectively adsorbing boron to remove the boron compd. on the polarizing film surface. Mannitol, sorbose, glucose and fructose are preferably used, and sorbitol is more preferably used. The concn. of the aq. saccharides soln. is preferably controlled to 0.1-10 wt.%. |
