Patent Application
20070275186
The present invention will be illustrated further in detail based on examples below, however, it is needless to say that the present invention is not limited to the examples at all. “%” and “parts” in examples and comparative examples are % by weight and parts by weight unless otherwise stated. Salts of compounds are expressed in the form of sodium salt.
170 parts of a bisazo compound of the formula (III-1):
and 30 parts of sodium nitrite were added to 1500 parts of water, then, 120 parts of 35% hydrochloric acid was added at 20 to 30° C. and the mixture was stirred for 2 hours, to perform diazotization. Excess sodium nitrite was removed by adding sulfamic acid, to obtain diazo liquid.
Next, the above-mentioned diazo liquid was added over 1 hour into liquid containing a compound of the formula (IV-1):
while maintaining pH at 7 using an aqueous sodium carbonate solution.
After completion of addition, the mixture was stirred further for 1 hour, to obtain a polyazo compound of the above-mentioned formula (V-1). λmax of this polyazo compound was 565 nm in an aqueous medium.
25 parts of a compound of the formula (V-1) was added to 500 parts of water, and 6 parts of anhydrous copper sulfate and 8 parts of monoethanolamine were added and the mixture was heated up to 95° C., and reacted for 12 hours. Then, the mixture was cooled down to 30° C., then, 35% hydrochloric acid was added to give pH 7, then, salting out is performed using sodium chloride, and the deposited crystal was filtrated, to obtain a compound of the formula (I-1). λmax of the compound (I-1) was 598 nm in an aqueous medium.
A compound of the formula (II-1) was obtained in the same manner as described above except that a compound of the formula (VI-1) was used instead of the bisazo compound of the formula (III-1).
A polyvinyl alcohol film [Kuraray Vinylon #7500, manufactured by Kuraray Co., Ltd.] having a thickness of 75 μm was mono-axially stretched to five-fold, to obtain a polarizing film substrate . This polyvinyl alcohol film was, while being kept under tension state, immersed in an aqueous solution of 73° C. containing 0.175% of the above-mentioned compound (I-1) and 0.035% of the above-mentioned compound (II-1) as polarizing film dyes, and containing 0.02% of mirabilite as a dyeing aid. Next, the polarizing film was immersed for 5 minutes in a 7.5% boric acid aqueous solution of 78° C., then, taken out, washed with water of 20° C. for 20 seconds, and dried at 50° C. to obtain a polarizing film. λmax of the resultant polarizing film was 620 nm (SHIMADZU UV2450, spectrophotometer [manufactured by Shimadzu Corporation]).
The orthogonal transmittance in the wavelength range of 550 nm to 700 nm was measured by the same spectrophotometer, and the results were shown in Table 1. When calculation was performed while hypothesizing the orthogonal transmittance at the detection limitation or lower to be 0, the average orthogonal transmittance was 0.004%, and light leakage in this wavelength range was extremely small. The orthogonal transmittance at 700 nm was 0.04%, and light leakage at 700 nm was small.
The resultant polarizing film was irradiated with light at 100° C. for 120 hours by a high pressure mercury lamp of a brilliance of 405 mW/cm2 (red light) situated at a position 25 cm remote from the polarizing film, then, the value of ΔA(%) was 4.2%, and light resistance against exposure under high temperature for a long period of time was also excellent. When the value of absorbance at 0 hour is represented by A(0) and the value of absorbance after 96 hours is represented by A(96), ΔA(%) is defined as described below.
ΔA(%)=((A(0)−A(96))/A(0))×100
A polarizing film was obtained in the same manner as in Example 1 excepting that only the compound (I-1) was used in an amount of 0.2% as the polarizing film dye to be contained in an aqueous solution into which the stretched polarizing film substrate was immersed. λmax of the resultant polarizing film was 610 nm.
The orthogonal transmittance in the wavelength range of 550 nm to 700 nm was shown in Table 1. When calculation was performed while hypothesizing the orthogonal transmittance at the detection limitation or lower to be 0, the average orthogonal transmittance was 0.125%, and light leakage in this wavelength range was large. The orthogonal transmittance at 700 nm was 1.32%, and light leakage at this wavelength was large.
ΔA was measured in the same manner as in Example 1, then, the value of ΔA was 4.0%, meaning light resistance equivalent to that of the present invention.
A polarizing film was obtained in the same manner as in Example 1 excepting that only the compound (II-1) was used in an amount of 0.2% as the polarizing film dye to be contained in an aqueous solution into which the stretched polarizing film substrate was immersed. λMax of the resultant polarizing film was 620 nm.
The orthogonal transmittance in the wavelength range of 550 nm to 700 nm was shown in Table 1. When calculation was performed while hypothesizing the orthogonal transmittance at the detection limitation or lower to be 0, the average orthogonal transmittance was 0.073%, and light leakage in this wavelength range was somewhat large. The orthogonal transmittance at 700 nm was 0.04%, and light leakage at this wavelength was small.
ΔA was measured in the same manner as in Example 1, then, the value of ΔA was 6.0%, meaning light resistance inferior to that of the present invention.
The polarizing film of the present invention can be used suitably for liquid crystal displays such as car navigations, liquid crystal projectors, projection televisions and the like.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-143560 | May 2006 | JP | national |
| 2006-226398 | Aug 2006 | JP | national |
