| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a polarizing film which is not fractured in a heat cycle test and has excellent durability and to provide its manufacturing method and a polarizing plate using the polarizing film. <P>SOLUTION: In the polarizing film, a dichroic coloring matter is adsorbed and aligned onto a polyvinyl alcohol resin film, boron content is 3 to 3.9 wt.% and when a sample of 2×8 mm size with a stretching axis direction as a short side is heated at 80°C, shrinkage force in a direction perpendicular to a stretching axis is 2.8 N or less. The polarizing plate using the polarizing film is also provided. When the polarizing film is manufactured by successively subjecting the polyvinyl alcohol resin film to swelling treatment, dyeing treatment and boric acid treatment and further to uniaxial stretching in at least one process among these treatment processes, the boric acid treatment is performed separately by first boric acid treatment which is performed in an aqueous solution containing 2 to 5 parts weight of boric acid per 100 pts.wt. of water at 50 to 70°C and second boric acid treatment which is performed in an aqueous solution with lower boric acid concentration than that of the aqueous solution used in the first boric acid treatment and at lower temperature than that used in the first boric acid treatment. <P>COPYRIGHT: (C)2009,JPO&INPIT |
