KR101013291B1 - Dye-containing polarizer - Google Patents

Abstract

An object of the present invention is to provide a high performance polarizing plate having less influence of by-products contained in the dye and having excellent polarization performance, moisture resistance and heat resistance in the visible light region and the ultraviolet region.

The transmittance at 380 nm is at least 70% on at least one surface of the dye-based polarizing film containing, as a form of the free acid, a water-soluble dye represented by the following formula (1) or a high-purity product of 90% or more of the salt thereof in the polyvinyl alcohol resin film: The polarizing plate with which the film is bonded.

In the above formula, R1, R2 represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxyl group or a carboxyl group, R3, R4 represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxyl group or a hydroxyl group, 0, S, NH or NCH ₃ is represented. In addition, l, m represents 0, 1 or 2, and l + m> 0.

Description

Dye-based polarizer {DYE-CONTAINING POLARIZER}

The present invention relates to a dye-based polarizing plate comprising a high-purity azo compound-based water-soluble dye or a salt thereof.

A polarizing plate having a light transmission / shielding function is a basic component of a liquid crystal display (LCD) together with a liquid crystal having a light switching function. The field of application of the LCD also ranges from early devices such as electronic calculators and watches to notebooks, word processors, liquid crystal projectors, liquid crystal televisions, car navigation systems, and indoor and outdoor measurement equipment.

Moreover, the polarizing plate made into the ultraviolet region (400 nm or less) is used for spectroscopic analyzers, such as a fluorescence spectrophotometer, the exposure apparatus which irradiates an ultraviolet light. Moreover, as a display use, as described in nonpatent literature 1, nonpatent literature 2, nonpatent literature 3, etc., it is for the liquid crystal display device provided with the fluorescent layer which emits light by the action of a near-ultraviolet ray ("photoluminescence" It can also use as a polarizing plate of "the liquid crystal display device."

As a polarizing plate which has absorption in such an ultraviolet region, a polarizing film is currently used as a polarizing element in polarizing film base materials, such as the film of the polyvinyl alcohol or its derivative (s) extended | stretched. Polyene-based film containing iodine or dichroic dye or polyene produced by orientation of dehydrochloric acid of polyvinyl chloride film or dehydration of polyvinyl alcohol-based film Etc. are known.

Among them, the iodine polarizing film using iodine as the polarizing element is excellent in the initial polarization performance in the visible light region, but in the near-ultraviolet region, its polarization performance is considerably inferior, and it is weak against water and heat, and has high temperature and high humidity. When used for a long time in the state of), there is a problem in its durability. In order to improve the durability, a method of treating with an aqueous solution containing formalin or boric acid or using a polymer film having a low water vapor permeability as a protective film is considered, but this is not sufficient.

On the other hand, the dye-based polarizing film using a dichroic dye as a polarizing element is excellent in moisture resistance and heat resistance compared with these iodine-based polarizing films, but it cannot be said that it is still enough as the polarization characteristic of an ultraviolet region.

As the dye used for the manufacture of the dye-based polarizing film as described above, the water-soluble compounds described in Patent Document 1, Patent Document 2, etc. have been mentioned, but none of the polarization performance, durability at high temperature and high humidity conditions is good. The improvement is desired.

On the other hand, when preparing the compound represented by Formula (1), the method of processing the amino compound represented by Formula (2) with sodium hypochlorite in water solvent is common, in this case, it is represented by Formula (3) Many by-product azine compounds are contained. Therefore, when used as a polarizing film, since the azine compound of Formula (3) is also contained in a base material simultaneously, the problem that the target polarization characteristic is not obtained arises.

Therefore, it was difficult to obtain a polarizing plate having excellent polarization performance, moisture resistance, and heat resistance in the visible and ultraviolet regions.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-357719

Patent Document 2: Japanese Patent Application Laid-Open No. 2003-35819

Patent Document 3: Japanese Patent Application Laid-Open No. 54-153648

Patent Document 4: Japanese Patent No. 1854685

Patent Document 5: Japanese Patent No. 2622748

Patent Document 6: Japanese Patent Application Laid-Open No. 1-252904

Patent Document 7: Japanese Patent Application Laid-Open No. 2001-27708

Patent Document 8: Japanese Patent Application Laid-Open No. 2001-33627

[Non-Patent Document 1] W. A. Crossland, et al., Journal of the SID 6/2, 1998, pp. 117-124

[Non-Patent Document 2] W. A. Crossland, et al., SID 97 Digest, pp. 837-840

[Non-Patent Document 3] S. L. Njo, et al., SID OO Digest, pp. 343-345

An object of the present invention is to provide a high-performance polarizing plate having less influence of by-products contained in the dye and having excellent polarization performance, moisture resistance and heat resistance in the visible light region and the ultraviolet region.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to achieve such an objective, the present inventors discovered that the polarizing film and polarizing plate containing dye of high purity have the outstanding polarization performance, moisture resistance, and heat resistance, and completed this invention. It was.

That is, the present invention

(1) Equation (1) below in the form of a free acid

(Wherein R1, R2 represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxyl group or a carboxyl group, R3, R4 represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxyl group or a hydroxyl group, Ⅹ Represents 0, S, NH or NCH _{3. In} addition, l, m represents 0, 1 or 2, and l + m> 0.)

A dye-based polarizing film containing a water-soluble dye having a purity of 90% or more or a salt thereof in a polyvinyl alcohol resin film, wherein the polarizing film functions as a polarizer in the near ultraviolet region of 300 nm to 400 nm,

(2) A polarizing plate, wherein a film having a transmittance of 70% or more at 380 nm is bonded to at least one surface of the near ultraviolet polarizing film according to (1) above,

(3) The polarizing plate as described in said (1) contains one or more types of organic dyes other than the water-soluble dye of Formula (1) or its salt which function as a polarizer in a visible light region,
(4) The polarizing film as described in said (1) contains one or more types of organic dyes or its salts other than the water-soluble dye of Formula (1) which functions as a polarizer in a visible light region in at least one surface of this polarizing film, A film with a transmittance of 70% or more at 380 nm is bonded to the polarizing plate.

[Effects of the Invention]

As for the polarizing film of this invention, compared with the polarizing film containing the azo compound produced by the conventional manufacturing method, the polarization characteristic is improved significantly. Moreover, since the polarizing plate of this invention has high polarization performance in the near ultraviolet region and is excellent also in durability, it is suitable for the display use of the photoluminescence liquid crystal display device and industrial instruments used in various environments.

BEST MODE FOR CARRYING OUT THE INVENTION [

The polarizing film of this invention contains the high purity product of 90% or more of the azo compound or its salt represented by Formula (1).

In Formula (1), R1 and R2 represent a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxyl group, or a carboxyl group, and R3, R4 represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxyl group, or a hydroxyl group. And 나타낸다 represents 0, S, NH or NCH ₃ . In addition, l, m represents 0, 1 or 2, and l + m> 0.

The azo compound represented by Formula (1) of high purity or its salt is obtained by processing the amino compound represented by General formula (2) using oxidative coupling with manganese dioxide as an oxidizing agent.

Next, the typical example of the azo compound or its salt represented by Formula (1) used by this invention is shown below.

When the azo compound of the formula (1) is present in the form of a salt, the salt may be an alkali metal salt such as lithium salt, sodium salt or potassium salt, ammonium salt, organic amine salt, and the like. Or potassium salt.

The base material (polymer film) used for the polarizing film of the present invention is preferably a polyvinyl alcohol base material. As the polyvinyl alcohol base material, polyvinyl alcohol or a derivative thereof, and any one of them, such as ethylene and propylene The thing modified | denatured with olefin, unsaturated carboxylic acid, such as crotonic acid, acrylic acid, methacrylic acid, maleic acid, etc. are mentioned. Especially, the film which consists of polyvinyl alcohol or its derivative (s) is used suitably from the point of adsorption and orientation of dye.

The compound represented by the formula (1) of the present invention or a salt thereof is used alone and, if necessary, can be blended with other organic dyes having polarization properties in the visible region, whereby a polarizing film having high polarization properties can be produced. . As other organic dyes to be blended, any dye may be used as long as it has a high dichroic dye as a dye having an absorption characteristic in a wavelength range different from the absorption wavelength region of the compound of the formula (1) of the present invention, for example, C.I. Direct yellow 12, C.I. Direct Yellow 44, C.I. Direct Orange 26, C.I. Direct Ossie Orange 39, C.I. Direct Orange 107, C.I. Direct Red 2, C.I. Direct Red 31, C.I. Direct Red 79, C.I. Direct Red 81, C.I. Direct Red 247, C.I. And the dyes described in Direct Green 80, C. or I. Direct Green 59, Patent Document 4, Patent Document 5, Patent Document 6 or Patent Document 7, and the like, and these dyes include free acid, alkali metal salt, ammonium salt, It is used as salt, such as an amine salt.

When including the compound represented by Formula (1) of this invention or its salt in a polymer film, the method of dyeing a polymer film is employ | adopted normally. Dyeing is performed as follows, for example. First, the water-soluble dye is dissolved in water to adjust the salt bath. The dye concentration in the salt bath is not particularly limited, but is usually selected in the range of about 0.001 to 10% by weight. And dyeing adjuvant may be used as needed, For example, it is suitable to use a forget-me-not in the density | concentration of about 0.1 to 10 weight%. In this way, the polymer film is immersed and dyed in the adjusted salt bath. Dyeing temperature becomes like this. Preferably it is about 40-80 degreeC, More preferably, it is 70 degreeC-80 degreeC.

The orientation of the water-soluble dye is performed by stretching the dyed polymer film. As a method of extending | stretching, you may use any well-known method, such as a wet method and a dry method, for example. The stretching of the polymer film may be performed before dyeing as the case may be. In this case, the water-soluble dye is oriented at the time of dyeing. The polymer film containing and aligning the water-soluble dye is subjected to post-treatment such as boric acid treatment by a known method as necessary. Such post-treatment is performed for the purpose of improving the light transmittance and polarization degree of a polarizing film. The conditions of the boric acid treatment vary depending on the kind of the polymer film to be used and the kind of the dye to be used. Generally, the boric acid concentration of the boric acid aqueous solution is in the range of 0.1 to 15% by weight, preferably 1 to 10% by weight, The treatment is carried out in a temperature range of 30 to 80 캜, preferably 40 to 75 캜. Further, if necessary, fix treatment may be performed together with an aqueous solution containing a cation-based high molecular compound.

The polarizing film obtained by this invention is used as a polarizing plate of spectroscopic analyzers, such as a fluorescence spectrophotometer, and a photoluminescence liquid crystal display device, using a protective film as a polarizing plate. In this way, by including in the polymer film together with other organic dyes having polarization characteristics in the visible light region, it becomes suitable for inspecting defects such as disorder in the orientation of the LCD.

The dye-based polarizing film thus obtained can be bonded to one or both surfaces of the protective film having excellent optical transparency and mechanical strength by using a polyvinyl alcohol-based or isocyanate-based adhesive to form a polarizing plate. Although the material which forms a protective film may be used conventionally, For example, in addition to a cellulose acetate film and an acryl-type film, fluorine-type films, such as a tetrafluoroethylene / hexafluoropropylene copolymer, , Films made of polyester resins, polyolefin resins or polyamide resins are used. The protective film used here needs to have a transmittance of 70% or more at 380 nm, and preferably has a transmittance of 80% or more.

The surface of the polarizing plate of the present invention may further comprise a layer subjected to antireflection treatment, antiglare treatment, antistatic treatment, corona treatment, and hard coat treatment.

The dye-based polarizing plate thus constructed is excellent in polarization performance, and furthermore, does not cause discoloration or deterioration of polarization performance even at high temperature and high humidity, and there is no light leakage at orthogonal positions in the visible and near ultraviolet regions. Has

EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, these are illustrative and do not limit this invention at all. % And part in an Example are a basis of weight unless there is particular notice.

Synthesis Example 1

350 parts of manganese dioxide (powder; Japanese fine chemicals, special reagent) in an aqueous solution of 25.5 parts of 2- (4-aminophenyl) -6-methylbenzothiazole-7-sulfonic acid (78.3% purity) dissolved in 260 parts of water 200 parts of 10% aqueous potassium permanganate solution was added to complete the oxidative coupling, sodium thiosulfate was added to remove excess potassium permanganate, and the manganese dioxide was filtered out. It filtered and obtained 13.7 parts of salts of the azo compound represented by said Formula (4).

Example 1

The maximum absorption wavelength in water of the azo compound (4) prepared in Synthesis Example 1 was 389 nm, and the high purity chromatography was measured using high performance liquid chromatography and found to be the purity of the azo compound of formula (4). Is 97%, and no azine compound as represented by formula (6) was detected.

Comparative Example 1

In general, C.I. The maximum absorption wavelength of the aqueous solution of Solophenyl Yellow FFL (manufactured by Ciba-Geigy) sold as Direct Yellow 28 was 395 nm. Moreover, as a result of measuring the chromatographic purity using high performance liquid chromatography, the purity of the azo compound of Formula (4) was 64%, and the by-product azine compound was 27%.

Example 2

Polyvinyl alcohol of 75 micrometers in thickness (brand name VF-XS # 7500, Kura of Japan) in the 45 degreeC aqueous solution which made the density | concentration of 0.1% of dye (4) and 0.1% of forget-me-not of the compound (4) manufactured by the synthesis example 1 Lesa) was immersed for 4 minutes. This film was stretched 5 times at 50 degreeC in 3% boric-acid aqueous solution, washed with water and dried, maintaining a tension state, and the polarizing film was obtained.

The maximum absorption wavelength of the obtained polarizing film was 406 nm, and had high polarization degree as a polarization rate of 98.5% when it was 43.75% of single plate transmittance. Moreover, durability was shown for a long time even in the state of high temperature and high humidity.

Comparative Example 2

Polyvinyl alcohol of 75 micrometers in thickness (brand name VF-XS # 7500, Japan) in 45 degreeC aqueous solution which made the density | concentration of 0.1% of Solophenyl Yellow FFL (made by Ciba-Geigy) and 0.1% of forget-me-not described in the comparative example 1 Kuraresa Co., Ltd.) was immersed for 4 minutes. This film was stretched 5 times at 50 degreeC in 3% boric-acid aqueous solution, washed with water and dried, maintaining a tension state, and the polarizing film was obtained.

The maximum absorption wavelength of the obtained polarizing film was 417 nm, and when it was 43.75% of single plate transmittance, it was 97.65% of polarization ratios.

Example 3 (Evaluation of polarizing plate for near ultraviolet rays)

Polyvinyl alcohol of 75 micrometers in thickness (brand name VF-XS # 7500, Kura Kura) of 75 micrometers in the aqueous solution of 45 degreeC made into the density | concentration of 0.5% of dye (4) manufactured by the synthesis example 1, and 0.1% of forget-me-not. Lesa) was immersed for 4 minutes. This film was stretched 5 times at 50 degreeC in 3% boric-acid aqueous solution, washed with water and dried, maintaining a tension state, and the polarizing film was obtained.

The orthogonal transmittance | permeability in 365 nm of the obtained polarizing film had high polarization performance as 0.1% or less and polarization degree 99.9%. TAC film (brand name: Fujitech T80SZ, product made in Japan's Tofu Photo Film Co., Ltd.) was affixed on both sides of this polarizing film using PVA-type adhesive, and the created polarizing plate is durable for a long time even in the state of high temperature and high humidity. Indicated.

Comparative Example 3

45% of a mixture composed mainly of a compound represented by the following formula (7) described in Patent Document 2 and Example 1 (mainly present in the form of sodium salt) as a main ingredient and 0.1% of forget-me-not. A 75-micrometer-thick polyvinyl alcohol (brand name VF-XS # 7500, the Kuraresa company of Japan) was immersed in the aqueous solution of ° C for 4 minutes. This film was stretched 5 times at 50 degreeC in 3% boric-acid aqueous solution, washed with water and dried, maintaining a tension state, and the polarizing film was obtained.
The orthogonal transmittance | permeability in 365 nm of the obtained polarizing film was 1.2%.

Since the polarizing film for near-ultraviolet of this invention has high polarization performance in the near-ultraviolet region, and also excellent durability, it is suitable for the display use of the photoluminescence liquid crystal display device and industrial instruments used in various environments.

Claims (4)

A dye-based polarizing film containing, in the form of a free acid, a water-soluble dye having a purity of 90% or more, or a salt thereof, represented by the following formula (1) below in a polyvinyl alcohol-based resin film, wherein the polarizing film is a near-ultraviolet region of 300 nm to 400 nm. It functions as a polarizer in the polarizing film characterized by the above-mentioned.

(Wherein R1, R2 represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxyl group or a carboxyl group, R3, R4 represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxyl group or a hydroxyl group, Ⅹ Represents 0, S, NH or NCH _{3. In} addition, l, m represents 0, 1 or 2, and l + m> 0.) The film whose transmittance | permeability in 380 nm is 70% or more is bonded to at least one surface of the near-ultraviolet polarizing film of Claim 1, The polarizing plate characterized by the above-mentioned. The polarizing film of Claim 1 contains one or more types of organic dyes other than the water-soluble dye of Formula (1) or its salt which function as a polarizer in a visible light region, The polarizing film characterized by the above-mentioned. The polarizing film of Claim 1 contains one or more types of organic dyes other than the water-soluble dye of Formula (1) which function as a polarizer in a visible light region, or its salt in a polarizing film, and the transmittance | permeability in 380 nm in at least one surface of this polarizing film. This 70% or more film is bonded together, The polarizing plate characterized by the above-mentioned.