There is provided a polarization film for near ultra-violet polarization plate manifesting high polarization ability at the near ultra-violet range of 370-400 nm, having sufficient endurance, and containing a monoazo compound represented by the following formula (I) or a salt thereof:
1
wherein
A represents a naphthyl having 1 to 3 sulfos or a phenyl having 1 to 2 water-soluble groups selected from sulfo and carboxyl and optionally having a lower alkyl or lower alkoxy,
R
1
to R
4
are the same or different and represent hydrogen, lower alkyl or lower alkoxy, and
R
5
represents —OR
6
or —NHR
6
wherein R
6
represents hydrogen, lower alkyl, lower alkyl sulfonyl, benzene sulfonyl, toluene sulfonyl, lower alkyl carbonyl or benzoyl, wherein the benzoyl is unsubstituted or substituted with nitro, amino or sulfo.
本发明提供了一种用于近紫外偏振片的偏振膜,该偏振膜在 370-400 纳米的近紫外范围内表现出较高的偏振能力,具有足够的耐久性,并含有下式 (I) 所代表的单偶氮化合物或其盐:
1
其中
A 代表具有 1 至 3 个磺基的
萘基,或具有 1 至 2 个
水溶性基团的苯基,这些基团选自 磺基和羧基,并可选择具有低级烷基或低级烷氧基、
R
1
至 R
4
相同或不同,代表氢、低级烷基或低级烷氧基,以及
R
5
代表-OR
6
或-NHR
6
其中 R
6
代表氢、低级烷基、低级烷基磺酰基、苯磺酰基、
甲苯磺酰基、低级烷基羰基或苯甲酰基,其中苯甲酰基未被取代或被硝基、
氨基或磺基取代。