Dye-based polarizing element and polarizing plate

A technology of polarizing elements and polarizers, which is applied in the direction of optical elements, polarizing elements, azo dyes, etc., can solve the problems of increased requirements for improvement, discoloration of polarizers, etc., and achieve the effect of good polarizing characteristics

Active Publication Date: 2014-01-08
NIPPON KAYAKU CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In addition, in recent years, the intensity of light sources for optical applications has increased, and there is a problem of discoloration of polarizers caused by the intense light and the accompanying heat, and the demand for improvement has increased.

Method used

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  • Dye-based polarizing element and polarizing plate
  • Dye-based polarizing element and polarizing plate
  • Dye-based polarizing element and polarizing plate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0069] The present invention will be described in more detail through examples below, but the present invention is not limited thereto. In addition, the evaluation of the transmittance and degree of polarization shown in an Example was performed as follows.

[0070] A protective film is attached to both sides of the original polarizing film (plain film), and the transmittance when the obtained two polarizers are laminated in the same direction as their absorption axes is defined as the parallel transmittance Tp. The transmittance when the polarizing plates are laminated so that their absorption axes are perpendicular to each other is referred to as the orthogonal transmittance Tc.

[0071] The degree of polarization Py is obtained from the parallel-position transmittance Tp and the cross-position transmittance Tc by the following formula.

[0072] Py={(Tp-Tc) / (Tp+Tc)}1 / 2×100

[0073] Each transmittance was measured using a spectrophotometer ["U-4100" manufactured by Hitachi,...

Synthetic example 1

[0075]

[0076] Dissolve 32.5 parts of 2-aminonaphthalene-4,8-disulfonic acid (common name: C acid) in 145 parts of water, add it to 140 parts of water containing 26 parts of 35% hydrochloric acid, at 15℃~20℃ Add 6.9 parts of sodium nitrite to carry out diazotization for 1 hour. Next, an aqueous solution containing 13.7 parts of 2-methoxy-4-methylaniline and 17.5 parts of 35% hydrochloric acid was added, and the coupling was carried out at 20°C for 4 hours while maintaining the pH at 3.0 to 3.5 with sodium acetate. , until it is confirmed that there is less than 2-methoxy-4-methylaniline by spot test. Next, 21.4 parts of 35% hydrochloric acid were added to this aminoazo compound, 6.9 parts of sodium nitrite was added at 10°C, and diazotization was performed twice at 15°C to 20°C for 2 to 3 hours. Next, it was added to an aqueous solution containing 31.5 parts of phenyl J acid, 125 parts of water, and 11 parts of sodium carbonate (Sorda ash), and further sodium carbonate sol...

Embodiment 1

[0078]

[0079] A polyvinyl alcohol-based resin film (VF series manufactured by Kuraray Co., Ltd.) having a saponification degree of 99% or more and a film thickness of 75 μm was immersed in warm water at 40° C. for 2 minutes to perform swelling treatment. The film after the swelling treatment was salted out using 25% by weight of Sanuki salt (Sanuki salt) in a 20% by weight aqueous solution of the pigment represented by formula (1), and dried at 60°C. The pigment powder (HPLC purity: 98.2%) was immersed in 0.05% by weight in a 45° C. aqueous solution containing 0.1% by weight of sodium tripolyphosphate to adsorb the dye. The dye-adsorbed membrane was washed with water, and after washing, boric acid treatment was performed for 1 minute with a 40° C. aqueous solution containing 2% by weight of boric acid. The film obtained by performing the boric acid treatment was stretched 5.0 times and treated in a 55° C. aqueous solution containing 3.0% by weight of boric acid for 5 minut...

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Abstract

[Problem] To develop a polarizing element having favorable polarizing characteristics and that is a pigment having an excellent blue dye without using a starting material belonging to specific chemical substances such as dianisidine. [Solution] The polarizing element, which contains dichroic pigments and comprises a film of a polyvinyl alcohol resin that has been stretched by a factor of at least three or a derivative thereof, is characterized by at least one of the dichroic pigments being the azo compound represented by formula (1) or a salt thereof, and the amount of the azo compound represented by formula (2) or a salt thereof contained being within 10% of the total amount of dichroic pigments.

Description

technical field [0001] The present invention relates to a dye-based polarizing element and a polarizing plate using the same. Background technique [0002] A polarizing element is usually produced by adsorbing iodine or a dichroic dye on a polyvinyl alcohol-based resin film and aligning it. A protective film made of triacetyl cellulose or the like is bonded to at least one side of the polarizing element via an adhesive layer to form a polarizing plate, which is used in a liquid crystal display device or the like. A polarizing plate using iodine as a dichroic dye is called an iodine-based polarizing plate, and a polarizing plate using a dichroic dye as a dichroic dye is called a dye-based polarizing plate. Among them, regarding the dye-based polarizing plate, when comparing polarizing plates having the same degree of polarization, the transmittance of the dye-based polarizing plate is lower than that of the iodine-based polarizing plate, that is, it has a problem of low cont...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B5/30C09B31/072C09B45/08C09B45/24C09B45/26G02F1/1335
CPCC09B45/28G02B5/3033C09B31/08C09B67/0055Y10T428/31938C09B31/072C09B45/08C09B45/24C09B45/26G02B5/30G02F1/1335G02B1/08
Inventor 望月典明樋下田贵大西口卓斗
Owner NIPPON KAYAKU CO LTD
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