| 摘要 |
PROBLEM TO BE SOLVED: To develop a highly durable polarizing plate having a stable transmittance of light and degree of polarization. SOLUTION: The polarizing plate is obtained by forming a transparent protective layer on one surface or both surfaces of a polarizing film prepared from a stretched film of a hydrophilic polymer containing >=0.6 wt.% dichroic material. The polarizing plate shows <=3% change rate of the transmittance and degree of polarization in terms of absolute values before and after the plate is left in an atmosphere of 60 deg.C and 90% RH for 500 hours. The polarizing film is produced by subjecting a hydrophilic polymer film to swelling treatment with a water-based medium, to dyeing treatment with a dichroic material, and to crosslinking treatment while suppressing the permanent elongation of the film to <=2.8 times the initial state, and then by subjecting the film to stretching treatment to >=5 times elongation of the initial state. Thus, the polarizing film having an excellent content of the dichroic material and a high degree of polarization degree can be stably and efficiently obtained. A polarizing plate having excellent durability is obtained by forming a transparent protective layer on the polarizing film.
|
