JP2008257025A - Polarizing plate, optical member provided with the same and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate which is a thin type, has excellent optical characteristics and, at the same time, satisfactorily maintains endurance, and to provide an optical member and a liquid crystal display device using the polarizing plate. <P>SOLUTION: The polarizing plate 100 comprises a polarizer 11 and a coating layer 12 which is formed on at least one surface of the polarizer, wherein the coating layer 12 is a layer formed with a composition including a water-soluble resin (A) and a water-soluble organometallic compound (B) comprising at least one kind selected from a water-soluble organic titanium compound and a water-soluble organic zirconium compound. The coating layer 12 can be disposed on one surface of the polarizer 11, a transparent protective layer 13 can be disposed on the other surface and a pressure-sensitive adhesive layer 14 can be disposed on the outside of the coating layer 12. Another optical layer can be stacked on the polarizing plate to form an optical member. Further, the polarizing plate can be stuck to a liquid crystal cell on the pressure-sensitive adhesive layer 14 side to fabricate the liquid crystal display device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thin polarizing plate excellent in durability and optical characteristics, and an optical member and a liquid crystal display device including the polarizing plate.

  As a polarizing plate used for a liquid crystal display device (LCD), a polarizing plate having protective layers on both sides of a polarizer has been used so far. As the protective layer, resin films such as triacetyl cellulose and cyclic olefin resins have been used. However, these resin films have a thickness of several tens of μm, and it is difficult to say that these resin films are suitable members for thinning LCDs in recent years. The protective layer generally has a refractive index anisotropy. Therefore, when the above-described protective layer is used in the high viewing angle LCD which has been rapidly spread recently, a protective layer made of a film having refractive index anisotropy may be disposed between the polarizer and the liquid crystal cell. Thus, there is a problem that the original viewing angle characteristic is deteriorated.

  Although the above-mentioned triacetyl cellulose does not have much in-plane refractive index anisotropy, it has a thickness direction retardation value of about 30 to 70 nm, and this retardation causes a reduction in viewing angle characteristics. ing. This phenomenon is particularly noticeable in a liquid crystal mode called an IPS (In-plane Switching) mode, but in other VA (Vertical Alignment) modes and TN (Twisted Nematic) modes. However, it is often beneficial to use a polarizing plate having no retardation value, such as that of triacetylcellulose, from the viewpoint of the degree of freedom in design and the like.

  In recent years, a protective layer made of a film of triacetyl cellulose having no refractive index anisotropy in the thickness direction or a cyclic olefin resin having a small refractive index anisotropy has been developed. However, when these protective layers are formed, the resin is molded as a single free-standing film and then bonded to the polarizer. Therefore, a thickness sufficient to handle the free-standing film is required, and the thickness is several tens of μm. It extends to. Therefore, it is hard to say that it is the most suitable member for application to a thin LCD. In addition, although the refractive index anisotropy is small, it often has a phase difference of several nm, which causes a decrease in front contrast and viewing angle characteristics.

  Thus, considering only the optical characteristics, it is preferable not to dispose a protective layer on the surface of the polarizer on the liquid crystal cell side. However, it is known that if the protective layer on the surface on the liquid crystal cell side of the polarizer is simply removed, deterioration such as cracks occurring in the polarizer due to environmental changes or the like occurs.

  Patent Document 1 discloses a protection comprising a transparent synthetic resin film on the adhesive surface of a synthetic resin film (1) having an adhesive layer on one side for the purpose of providing a polarizing plate that achieves both lightness and durability. A polarizing plate is proposed in which a polyvinyl alcohol polarizing film (4), an adhesive layer (5), and a release film (6) are sequentially laminated on the layer (2) via an adhesive layer (3). Has been.

  In Patent Document 2, a structure in which a TAC (triacetyl cellulose) film is formed only on the outer side of a polarizer film is adopted for thinning, and a warping that causes a bonding target side to be concave does not occur. For the purpose of accurately and efficiently performing the joint work, a shape-retaining film that keeps the polarizer film or retardation film in a flat state is provided on both sides of one side of the polarizer film or retardation film. Laminating and laminating a protective film on the opposite side of the laminated side of the polarizer film or retardation film in the shape-retaining film so that peeling can be prevented, and the warpage that the concave side of the polarizer film or retardation film occurs can be prevented. An optical film in which the protective film is set to a predetermined thickness has been proposed.

  In Patent Document 3, for the purpose of providing a polarizing film and a display device having improved surface quality without unevenness, a polarizing sheet-like polarizer, and a protective layer adhered to one surface side of the polarizer, A polarizing film comprising an adhesive layer formed on the surface of the polarizer opposite to the surface of the protective layer has been proposed.

  Patent Document 4 aims to further reduce the thickness and weight of a polarizing plate by forming a thin protective layer on a polarizing film made of a polyvinyl alcohol-based resin without substantially using an organic solvent. There has been proposed a polarizing plate characterized in that a release film is laminated on at least one surface of a polarizing film made of a polyvinyl alcohol-based resin film via a protective layer made of a water-soluble film-forming composition.

However, even the techniques of Patent Documents 1 to 4 have not yet achieved a polarizing plate that is lightweight and has a sufficiently high durability and optical characteristics.
Japanese Patent Laid-Open No. 10-186133 JP 2001-108830 A JP 2002-14226 A Japanese Patent Laid-Open No. 2005-43858

  Accordingly, it is an object of the present invention to provide a polarizing plate that is thin and has high optical characteristics and also maintains good durability, and an optical member and a liquid crystal display device including the polarizing plate.

  As a result of research, the present inventors have formed a coating layer using a water-based composition containing a specific water-soluble substance on the surface of the polarizer, so that, for example, a pressure-sensitive adhesive layer is formed on the coating layer side. It has been found that a polarizing plate having excellent durability can be obtained even when it is bonded to a liquid crystal cell via, for example, the present invention.

  That is, the present invention includes a polarizer and a coating layer formed on at least one surface of the polarizer, and the coating layer includes a water-soluble resin (A), a water-soluble organic titanium compound, and a water-soluble organic zirconium compound. And a polarizing plate which is a layer formed from a composition comprising at least one water-soluble organometallic compound (B) selected from the group consisting of:

  In the polarizing plate of the present invention, it is preferable that the coating layer is formed on one surface of the polarizer, and a protective layer made of a transparent resin film is further formed on the surface of the polarizer opposite to the surface on which the coating layer is formed.

  In the polarizing plate of the present invention, the transparent resin film is preferably made of a resin selected from a cellulose resin, a cyclic olefin resin, and a chain olefin resin.

  In the polarizing plate of the present invention, the water-soluble resin (A) is preferably a polyvinyl alcohol resin.

In the polarizing plate of the present invention, the water-soluble organometallic compound (B) is an organic titanium compound, and the following formulas (1) and (2):
(HO) ₂ Ti [OCH (CH ₃ ) COOH] ₂ (1)
(C ₃ H ₇ O) ₂ Ti [OCH ₂ CH ₂ N (CH ₂ CH ₂ OH) ₂ ] ₂ (2)
It is preferable that it consists of 1 or more types selected from the compound represented by these.

  In the polarizing plate of this invention, it is preferable that the thickness of a coating layer exists in the range of 1-20 micrometers.

  In the polarizing plate of the present invention, a pressure-sensitive adhesive layer can be further formed so as to face the polarizer with the coating layer interposed therebetween.

  The present invention also relates to an optical member comprising a laminate in which any one of the polarizing plates described above and an optical layer are laminated.

  The present invention also relates to a liquid crystal display device in which the polarizing plate of the present invention is formed on at least one surface of a liquid crystal cell, and the polarizing plate is bonded to the liquid crystal cell with a pressure-sensitive adhesive layer.

  According to the present invention, it is possible to provide a polarizing plate, an optical member, and a liquid crystal display device that are thin and have high optical characteristics while maintaining good durability.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings as appropriate. However, the present invention is not limited to the illustrated configuration.

[Polarizer]
The polarizing plate of the present invention includes a polarizer and a coating layer formed on at least one surface of the polarizer. The coating layer comprises a water-soluble resin (A), a water-soluble organometallic compound (B) comprising at least one selected from a water-soluble organic titanium compound and a water-soluble organic zirconium compound (hereinafter simply referred to as a water-soluble organic compound). And a metal compound (B).).

  FIG. 1 is a cross-sectional view showing an example of the configuration of a polarizing plate according to the present invention. In the polarizing plate 100 shown in FIG. 1, a coating layer 12 that is a layer formed from a composition containing a water-soluble resin (A) and a water-soluble organometallic compound (B) is disposed on one side of the polarizer 11. ing.

<Polarizer>
As the polarizer 11, for example, a polyvinyl alcohol resin can be used. More specifically, the polyvinyl alcohol resin film is uniaxially stretched and dyed with a dichroic dye to adsorb and align the dichroic dye. Can be used.

  The polyvinyl alcohol-based resin used for constituting the polarizer 11 can be typically obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group. The saponification degree of the polyvinyl alcohol resin is usually about 85 to 100 mol%, preferably 98 mol% or more. This polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl formal and polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000.

  A film obtained by forming such a polyvinyl alcohol resin is suitably used as a raw film of the polarizer 11. The method for forming a polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method. Although the film thickness of this raw film is not specifically limited, For example, it is about 10 micrometers-150 micrometers.

  The polarizer 11 is usually a step of obtaining a uniaxially stretched film by uniaxially stretching the original film of the polyvinyl alcohol resin as described above, and dyeing with a dichroic dye to adsorb the dichroic dye to the film. It is manufactured through a step of obtaining a dyed film, a step of treating with a boric acid aqueous solution after dyeing, and a step of washing with water after the treatment with the boric acid aqueous solution.

  Uniaxial stretching may be performed before dyeing with a dichroic dye, may be performed simultaneously with dyeing, or may be performed after dyeing. When uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Of course, it is also possible to perform uniaxial stretching in these plural stages. In uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. Further, for example, it may be dry stretching in which stretching is performed in the air, or may be wet stretching in which stretching is performed while being swollen with a solvent. The draw ratio is usually about 3 to 8 times.

  In order to dye the polyvinyl alcohol resin film with the dichroic dye, for example, the polyvinyl alcohol resin film may be immersed in an aqueous solution containing the dichroic dye. Specifically, iodine or a dichroic dye is used as the dichroic dye. The polyvinyl alcohol-based resin film is preferably subjected to an immersion treatment in water, particularly warm water, before the dyeing treatment.

  When iodine is used as the dichroic dye, a method of dyeing a polyvinyl alcohol resin film by dipping it in an aqueous solution containing iodine and potassium iodide is usually employed. The content of iodine in this aqueous solution is usually about 0.01 to 1 part by mass per 100 parts by mass of water, and the content of potassium iodide is usually about 0.5 to 20 parts by mass per 100 parts by mass of water. . The temperature of the aqueous solution used for dyeing is usually about 20 to 40 ° C., and the immersion time (dyeing time) in this aqueous solution is usually about 20 to 1,800 seconds.

On the other hand, when a dichroic dye is used as the dichroic dye, a method of immersing and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye in this aqueous solution is usually about 1 × 10 ⁻⁴ to 10 parts by mass, preferably about 1 × 10 ⁻³ to 1 part by mass per 100 parts by mass of water. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the aqueous dye solution used for dyeing is usually about 20 to 80 ° C., and the immersion time in this aqueous solution (that is, the dyeing time) is usually about 10 to 1,800 seconds.

  The boric acid treatment after dyeing with the dichroic dye can be performed by immersing the dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution. The amount of boric acid in the boric acid-containing aqueous solution is usually about 2 to 15 parts by mass, preferably about 5 to 12 parts by mass per 100 parts by mass of water. When iodine is used as the dichroic dye, this boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually about 0.1 to 15 parts by mass, preferably about 5 to 12 parts by mass per 100 parts by mass of water. The immersion time in the boric acid-containing aqueous solution is usually about 60 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50 ° C. or higher, preferably 50 to 85 ° C., more preferably 60 to 80 ° C.

  The polyvinyl alcohol resin film after the boric acid treatment is usually washed with water. The water washing treatment is performed, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. The temperature of water in the water washing treatment is usually about 5 to 40 ° C., and the immersion time is usually about 1 to 120 seconds. After washing with water, a drying process is performed. The drying process is usually performed using a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually about 30 to 100 ° C, preferably 50 to 100 ° C. The time for the drying treatment is usually about 60 to 600 seconds, preferably about 120 to 600 seconds.

  As described above, the polarizer 11 can be obtained by subjecting the polyvinyl alcohol-based resin film to uniaxial stretching, dyeing with a dichroic dye, and boric acid treatment. The thickness of the polarizer 11 can be about 5 to 40 μm.

<Coating layer>
The coating layer 12 formed in the present invention is a layer formed from a composition containing a water-soluble resin (A) and a water-soluble organometallic compound (B). In the present invention, by forming the coating layer on at least one surface of the polarizer, for example, the polarizing plate can be made thinner than in the case of forming a protective layer or the like, and good physical properties of the coating layer can be achieved. The durability of the polarizing plate can be sufficiently ensured even if a protective layer is not provided on the surface on the side where the coating layer is formed, due to the mechanical strength. In the polarizing plate on which the protective layer is formed, optical characteristics may be deteriorated due to the refractive index anisotropy of the protective layer. In the present invention, the coating layer as described above is provided on at least one surface of the polarizer. Therefore, durability can be ensured without forming a protective layer on the surface on which the coating layer is formed. Further, since the coating layer is relatively thin and hardly exhibits refractive index anisotropy, the optical characteristics of the polarizing plate can be improved according to the present invention. That is, in the present invention, for example, a color change due to an angle that occurs in a liquid crystal display device using a polarizing plate on which a protective layer is formed can be reduced, and excellent optical characteristics can be obtained.

(Water-soluble resin (A))
The composition prepared as a coating liquid for forming the coating layer of the present invention contains a water-soluble resin (A) from the viewpoint of ensuring adhesion with a polarizer comprising a polyvinyl alcohol resin. To do. Moreover, this composition typically contains a solvent in order to ensure coatability. The solvent used here is preferably water as a main component in order to uniformly dissolve the water-soluble resin (A), and water is used alone or a small amount of organic solvent is mixed with water. It is preferable to use a solvent.

  Examples of the water-soluble resin (A) include polyvinyl alcohol resins and water-soluble acrylic resins. Among these, a polyvinyl alcohol resin is preferably used in that it has excellent water solubility and excellent adhesion to a polarizer, and can easily impart the necessary physical strength to the coating layer. Polyvinyl alcohol resins include partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, polyvinyl alcohol modified with anions such as carboxyl groups, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, amino group-modified polyvinyl alcohol. Such a modified polyvinyl alcohol resin may be used. When a modified polyvinyl alcohol-based resin is used, characteristics such as water solubility can be easily controlled within a desired range depending on the type and amount of the functional group introduced by the modification.

  As a commercially available product of a suitable polyvinyl alcohol-based resin, “PVA-403” (trade name) which is a partially saponified polyvinyl alcohol sold by Kuraray Co., Ltd. and “KL-506” which is an anion-modified polyvinyl alcohol. (Product name) and the like. Details of these Kuraray polyvinyl alcohols are listed as “KUURARAY POVAL” on the company's website dedicated to poval resin (URL: http://www.poval.jp/japan/poval/topics/index.html). (Access date: March 20, 2007).

  The degree of polymerization of the polyvinyl alcohol resin is preferably in the range of 300 to 2,000. When the degree of polymerization is 300 or more, the strength of the coating layer is good, and when it is 2000 or less, the viscosity of the coating solution when the coating solution for forming the coating layer is prepared does not increase too much, The concentration of the water-soluble resin in the coating liquid can be increased. The degree of polymerization is more preferably in the range of 500 to 1800.

(Water-soluble organometallic compound (B))
Since the water-soluble resin (A) as described above including the polyvinyl alcohol-based resin is poor in water resistance by itself because of its water-solubility, in the present invention, in order to increase the water resistance of the water-soluble resin (A). Crosslink with a curing agent. For crosslinking, typically, a coating liquid prepared for forming a coating layer is allowed to contain a curing agent capable of crosslinking the water-soluble resin (A), and the coating liquid is applied. Can be adopted. In this case, the reaction between the water-soluble resin and the curing agent proceeds mainly by removing the solvent in the coating liquid. As the curing agent has higher reactivity with the water-soluble resin, the crosslinking density after the reaction can be increased, so that the resulting coating layer exhibits good water resistance.

  In the present invention, a water-soluble organometallic compound (B) composed of at least one selected from a water-soluble organic titanium compound and a water-soluble organic zirconium compound is used as a curing agent for the water-soluble resin (A). Since the water-soluble organometallic compound (B) has a high reactivity with the water-soluble resin (A), in the present invention, a coating layer having excellent water resistance can be formed. A polarizing plate is obtained. In the present specification, the water-soluble organotitanium compound and the water-soluble organozirconium compound each have a structure in which an organic group is bonded to titanium or zirconium directly or through another bond such as an oxygen atom or a nitrogen atom. , A compound having at least one in the molecule and showing water solubility. The water-soluble generally means a property capable of forming an aqueous solution, and the water-soluble organometallic compound (B) used in the present invention exists in a dissolved state when used as a coating solution. Typically, the amount dissolved in 100 g of water at 25 ° C. should be about 0.1 g or more.

  In the present specification, the organic group means a group containing at least a carbon element, and can be, for example, an alkyl group, an alkoxy group, an acyl group, or the like. The bond does not mean only a covalent bond, but may be a coordinate bond by coordination of a chelate compound or the like. The water-soluble organometallic compound (B) usually has a polar group such as a hydroxyl group, a carboxyl group, or an amino group in order to develop water solubility.

  As described above, the solvent to be included in the composition for forming the coating layer is water alone or a mixed solvent of water and a small amount of organic solvent in order to dissolve the water-soluble resin to obtain a uniform concentration distribution. It is preferable that Accordingly, water-soluble organic titanium compounds and organic zirconium compounds are also used.

Typical examples of the water-soluble organometallic compound (B) used in the present invention include the following formulas (1) to (4) from the viewpoint of being able to react well with various water-soluble resins (A).
(HO) ₂ Ti [OCH (CH ₃ ) COOH] ₂ (1)
(C ₃ H ₇ O) ₂ Ti [OCH ₂ CH ₂ N (CH ₂ CH ₂ OH) ₂ ] ₂ (2)
(HO) ₂ Zr [OCH (CH ₃ ) COOH] ₂ (3)
_{(C 3 H 7 O) 2} Zr [OCH 2 CH 2 N (CH 2 CH 2 OH) 2] 2 (4)
The organic titanium compounds represented by the above formulas (1) and (2) can be given as typical examples.

Examples of preferable commercially available water-soluble organotitanium compounds that can be used as the water-soluble organometallic compound (B) of the present invention include “Orgatics TC-310” and “Orgatics” sold by Matsumoto Pharmaceutical Co., Ltd. TC-315 "," Orgatechs TC-300 "," Orgachics TC-400 "(all are trade names), etc. Examples of preferable commercially available water-soluble organic zirconium compounds include “Orgachix ZB-400” (trade name) sold by Matsumoto Pharmaceutical Co., Ltd. About these commercial items, the chemical abbreviation name which the maker calls, its chemical structure, and concentration are shown below.
“Orgatics TC-310”: Chemical name of the manufacturer, “titanium lactate”; chemical structure is the above formula (1); 44% by mass of active ingredient, 40% by mass of isopropyl alcohol, and 16% by mass of water.
"Orgatix TC-315"manufacturer's abbreviation "titanium lactate"; chemical structure is the above formula (1); 44% by mass of active ingredient, 56% by mass of water.
“Orgatics TC-300”: Chemical name of the manufacturer, “titanium lactate”; chemical structure of the above formula (1); active ingredient 42% by mass, isopropyl alcohol 38% by mass, water 20% by mass.
“Orgatics TC-400”: chemical name “titanium triethanolamate” designated by the manufacturer; chemical structure is the above formula (2); 80% by mass of active ingredient, 20% by mass of isopropyl alcohol.
“Orgatix ZB-400”: chemical name of manufacturer “zirconium-based compound”; (chemical structure is unknown except that it is a water-soluble organic zirconium compound); active ingredient 30% by mass, water 70% by mass solution.

(Formation method of coating layer)
The coating layer in the present invention includes, for example, a composition containing the water-soluble resin (A), the water-soluble organometallic compound (B) and an appropriate solvent as a coating liquid, and the coating liquid is at least a polarizer. It can be formed by applying to one side. As described above, the solvent is preferably water alone or a mixed solvent of water and a small amount of an organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropyl alcohol, 1-propanol, 1 -Alcohols, such as butanol, can be illustrated. For example, a mixed solvent of water and a small amount of isopropyl alcohol tends to be advantageous in improving the coating workability. The mass ratio of water: organic solvent in the mixed solvent of water and organic solvent can be, for example, in the range of 100: 0 to 50:50.

  The content ratios of the water-soluble resin (A) and the water-soluble organometallic compound (B) in the coating liquid are not particularly limited. For example, the solution viscosity at 25 ° C. with a B-type viscometer of the coating liquid is 1 to 300 mPa · It can be adjusted to be about sec, more typically about 30 to 100 mPa · sec.

  The ratio of the water-soluble resin (A) and the water-soluble organometallic compound (B) used for forming the coating layer 12 is such that the water-soluble organometallic compound (B) 1 is 100 parts by mass of the water-soluble resin (A). It is preferable to be within the range of ˜200 parts by mass, and it may be appropriately determined according to the respective types of the water-soluble resin (A) and the water-soluble organometallic compound (B). In particular, the amount of the water-soluble organometallic compound (B) with respect to 100 parts by mass of the water-soluble resin (A) is preferably in the range of 5 to 200 parts by mass. Even if the amount of the water-soluble organometallic compound (B) is less than 5 parts by mass with respect to 100 parts by mass of the water-soluble resin (A), the water-soluble resin (A) is effective in improving the water resistance of the coating layer. A) When about 5 to 200 parts by mass is blended with respect to 100 parts by mass, it is preferable because an even better effect is exhibited in improving water resistance. The amount of the water-soluble organometallic compound (B) is more preferably in the range of 10 to 100 parts by mass, and more preferably in the range of 20 to 60 parts by mass with respect to 100 parts by mass of the water-soluble resin (A).

  The thickness of the coating layer 12 is preferably in the range of 1 to 20 μm. When the thickness of the coating layer 12 is 1 μm or more, the durability of the polarizing plate is particularly good, and when it is 20 μm or less, the optical properties of the polarizing plate are particularly good. The thickness of the coating layer 12 is particularly preferably in the range of 1 to 10 μm.

<Protective layer>
FIG. 2 is a cross-sectional view showing an example of the configuration of the polarizing plate according to the present invention. In the present invention, like the polarizing plate 200 shown in FIG. 2, the coating layer 12 is formed on one surface of the polarizer 11, and the transparent resin film is formed on the surface of the polarizer 11 opposite to the surface on which the coating layer 12 is formed. A protective layer 13 made of may be further formed. When the protective layer 13 is provided on one surface of the polarizer 11, the durability of the polarizing plate is particularly good. Also, good durability can be obtained without forming a protective layer on the surface on which the coating layer 12 is formed. In this case, for example, compared to a conventional configuration in which protective layers are formed on both sides of the polarizer, for example. The effect of improving the optical characteristics can be obtained sufficiently satisfactorily.

  Examples of the transparent resin film constituting the protective layer 13 include cellulose resin, cyclic olefin resin, chain olefin resin, polyimide, polyamide, polyether imide, polyether ketone, polyether sulfone, polyphenylene sulfide, and polyphenylene. Examples thereof include oxides, various polyesters, polyacetals, polycarbonates, and various poly (meth) acrylates. Among these, a resin selected from a cellulose resin, a cyclic olefin resin, and a chain olefin resin is advantageous in that it has a relatively small photoelastic coefficient, is colorless, and has excellent transparency.

  Preferred examples of the cellulose resin include cellulose acetates such as triacetyl cellulose and diacetyl cellulose. The cyclic olefin-based resin is a resin whose main component is a unit derived from cyclic olefins, and preferred examples of the cyclic olefins include norbornene, dimethanooctahydronaphthalene, and substituted products thereof. The chain olefin-based resin is a resin having a unit derived from a chain olefin as a main component. Examples of the chain olefins include ethylene, propylene, 1-butene, 1-pentene, 2-methylpentene-1, and the like. Can be preferably exemplified. Here, a main component means the component contained in the quantity exceeding 50 mass% of the whole.

  As a method for forming the protective layer 13, a conventionally known method can be appropriately used. For example, a method of bonding the protective layer 13 to the polarizer 11 through an adhesive can be particularly preferably employed. Here, examples of the adhesive include a water-based adhesive made of an aqueous solution of a polyvinyl alcohol resin, a solventless adhesive containing a curable component, and the like.

<Pressure-sensitive adhesive layer>
FIG. 3 is a cross-sectional view showing an example of the configuration of the polarizing plate according to the present invention. In the present invention, as in the polarizing plate 300 shown in FIG. 3, the pressure-sensitive adhesive layer 14 may be further formed so as to face the polarizer 11 with the coating layer 12 interposed therebetween. In this case, when forming an optical member or a liquid crystal display device using the polarizing plate of the present invention, the pressure-sensitive adhesive layer 14 can act as an adhesive layer between the polarizing plate and the optical layer, liquid crystal cell, or the like. .

  A pressure-sensitive adhesive is a viscoelastic material that can be removed without leaving any traces if it adheres to the surface of another substance simply by pressing it, and when it is peeled off from the surface of the adherend, it has sufficient strength. It is also called an adhesive. The pressure-sensitive adhesive includes acrylic type, urethane type, rubber type, and the like. From these, a transparent and optically isotropic type may be selected and used. Of these, an acrylic pressure-sensitive adhesive is preferably used.

  As a method for forming the pressure-sensitive adhesive layer 14, a known method can be used as appropriate. For example, a direct coating method in which an adhesive coating solution is directly applied to the coating layer 12 and dried, or on a transfer substrate. A transfer method of transferring a pre-formed pressure-sensitive adhesive layer onto the coating layer 12 can be particularly preferably employed. In forming the pressure-sensitive adhesive layer 14, it is also effective to subject the formation surface (that is, the surface of the coating layer 12) to an easy adhesion treatment such as a corona discharge treatment.

<Other layers>
In the polarizing plate of the present invention, for example, a surface treatment layer such as a hard coat layer, an antiglare layer, or an antireflection film may be further provided on the protective layer. Moreover, this protective layer may have a function as these surface treatment layers.

[Optical member]
The present invention also provides an optical member comprising a laminate in which any one of the polarizing plates described above and an optical layer are laminated. FIG. 4 is a cross-sectional view showing an example of the configuration of the optical member according to the present invention. An optical member 400 shown in FIG. 4 includes a polarizing plate 300 in which a protective layer 13 is formed on one surface of a polarizer 11, and a coating layer 12 and a pressure-sensitive adhesive layer 14 are formed on the other surface in this order. It consists of a laminated body in which the optical layer 21 is laminated on the pressure-sensitive adhesive layer 14 side. FIG. 4 shows a configuration in which the optical layer is formed only on one side of the polarizing plate (that is, the pressure-sensitive adhesive layer 14 side). However, in the present invention, the optical layer may be formed outside the protective layer 13. Alternatively, an optical layer may be formed on both sides of the polarizing plate.

  Examples of the optical layer include a retardation plate, a light collecting sheet, a diffusion film, a light guide plate, a light reflection sheet, a brightness enhancement film, an antiglare sheet, and the like, and an optical member by combining these optical layers according to the purpose. Can have desired optical characteristics. Among these, the retardation plate is usually provided outside the pressure-sensitive adhesive layer 14 as in FIG. In addition, the light collecting sheet, the diffusion film, the light guide plate, the light reflecting sheet, the brightness enhancement film, and the antiglare sheet are usually provided outside the protective layer 13, contrary to FIG. 4.

  Typical configurations of the optical member include, for example, a configuration in which a retardation plate, a polarizing plate, a diffusion film, a condensing sheet, a light guide plate, and a light reflection sheet are laminated in this order, a retardation plate, a polarizing plate, and a brightness enhancement film. The structure which laminated | stacked these in this order, the structure which laminated | stacked the phase difference plate and the polarizing plate in this order can be illustrated.

[Liquid Crystal Display]
The present invention also relates to a liquid crystal display device in which the polarizing plate of the present invention is formed on at least one surface of a liquid crystal cell, and the polarizing plate is bonded to the liquid crystal cell with a pressure-sensitive adhesive layer. For example, the polarizing plate 300 on which the pressure-sensitive adhesive layer 14 as shown in FIG. 3 is formed is bonded to at least one surface of the liquid crystal cell on the pressure-sensitive adhesive layer 14 side to obtain a liquid crystal display device. be able to.

  FIG. 5 is a cross-sectional view showing an example of the configuration of the main part of a liquid crystal display device according to another embodiment of the present invention. In the liquid crystal display device 500 shown in FIG. 5, an optical member 400 composed of a laminate of the polarizing plate 300 and the optical layer 21 as shown in FIG. 4 is arranged so as to sandwich the liquid crystal cell 31. In the liquid crystal display device 500 shown in FIG. 5, the pair of optical members 400 are disposed so as to face the liquid crystal cell 31 on the respective optical layer 21 side, but the present invention is not limited to this. Further, on one side of the liquid crystal cell, a polarizing plate 300 on which the pressure-sensitive adhesive layer 14 as shown in FIG. 3 is formed is bonded on the pressure-sensitive adhesive layer 14 side, and on the other side of the liquid crystal cell. 4 can also be made into a liquid crystal display device of another form by laminating the optical member 400 as shown in FIG. 4 via the pressure-sensitive adhesive layer on the optical layer 21 side.

  When the polarizing plate 300 on which the pressure-sensitive adhesive layer 14 as shown in FIG. 3 is formed is applied to a liquid crystal display device, the pressure-sensitive adhesive layer 14 side may be bonded to the liquid crystal cell. When the optical member 400 having the optical layer 21 as shown in FIG. 4 is applied to a liquid crystal display device, a pressure-sensitive adhesive layer is formed on the surface of the optical member, and the pressure-sensitive adhesive layer is The optical member and the liquid crystal cell can be bonded via each other.

  The liquid crystal cell constituting the liquid crystal display device includes various types known in the field of liquid crystal display devices such as TN (Twisted Nematic), STN (Super Twisted Nematic), VA (Vertical Alignment), and IPS (In-Plane Switching). Can be of mode. In particular, the effect of improving the viewing angle characteristics in the IPS mode liquid crystal display device is remarkably exhibited in the present invention.

  The liquid crystal cell typically includes a pair of opposing substrates, electrodes provided on one or both of the opposing surfaces of the substrate, and a liquid crystal layer filled in a region sandwiched between the substrates. It has the structure which contains at least. In the TN mode, STN mode, and VA mode, electrodes are provided on the opposing surfaces of the pair of substrates. In the IPS mode, parallel comb-like electrodes are arranged on the liquid crystal layer side of one substrate. In the case of the IPS mode, the polarizing plates disposed above and below the liquid crystal cell are usually normally black with their absorption axes orthogonal to each other. In this case, the absorption axis of one polarizing plate is parallel to the alignment direction of liquid crystal molecules during black display with no voltage applied (the slow axis of the liquid crystal cell), and the absorption axis of the other polarizing plate is orthogonal. Placed in. And when using as a transmissive liquid crystal display device, a backlight is arrange | positioned on the outer side of one polarizing plate.

  By using the polarizing plate of the present invention, it is possible to obtain a liquid crystal display device that is excellent in durability against environmental changes, such as preventing the occurrence of cracks in the polarizer, and is thin and excellent in optical characteristics. .

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these. A polarizing plate according to Example 1 and Comparative Examples 1 and 2, and a liquid crystal television as a liquid crystal display device were produced by the following procedure.

[Example 1]
<Preparation of coating solution for forming coating layer>
A commercially available anion-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd .: KL-506) was used as the water-soluble resin (A), and the polyvinyl alcohol was mixed in a water / isopropyl alcohol (IPA) mixed solution at the following composition ratio. And allowed to dissolve for several hours. Thereafter, the temperature was quickly raised to 80 ° C. and stirred for about 1 hour, and then the temperature of the solution was gradually returned to room temperature while continuing stirring to obtain a water / IPA solution of polyvinyl alcohol. While stirring the obtained polyvinyl alcohol solution, ORGATICS TC-310 was added as a water-soluble organometallic compound (B), and stirring was further continued for about 30 minutes to complete the coating solution.
Water 100.0 parts by mass IPA 12.9 parts by mass KL-506 12.9 parts by mass TC-310 12.9 parts by mass <Production of polarizing plate with single-sided protective layer>
A polarizing plate 300 having the configuration shown in FIG. 3 was produced. A PVA (polyvinyl alcohol) film having an average polymerization degree of about 2,400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm was uniaxially stretched about 5 times in a dry process and further kept at 60 ° C. After being immersed in pure water for 1 minute, it was dyed in an aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.05 / 5/100 at 28 ° C. for 60 seconds. Thereafter, it was immersed in an aqueous solution having a mass ratio of potassium iodide / boric acid / water of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Subsequently, the plate was washed with pure water at 26 ° C. for 20 seconds and then dried at 90 ° C. to obtain a 25 μm-thick polarizer 11 in which iodine was adsorbed and oriented on PVA.

  Separately, solution A in which 0.35 parts by mass of zinc chloride as a crosslinking reaction catalyst was added to an aqueous solution in which 3 parts by mass of specially modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd .: Z200) was dissolved in 100 parts by mass of water, and water A solution B in which 0.28 parts by mass of glyoxal which is a crosslinking agent for specially modified PVA and 100 parts by mass of 3 parts by mass of high saponification degree PVA (manufactured by Kuraray Co., Ltd .: PVA-117H) as a viscosity modifier Prepared and mixed solution A and solution B to make an aqueous adhesive. A triacetyl cellulose film (Konica Minolta Opto Co., Ltd .: KC4UY) (40 μm thickness) to be the protective layer 13 is adhered to one surface of the polarizer 11 obtained previously with the above aqueous adhesive, and the solvent is heated with hot air. By removing, a polarizing plate with a single-sided protective layer was obtained.

  The coating liquid prepared above is applied to the surface of the polarizing plate with a single-side protective layer opposite to the protective layer 13 with a desktop bar coater, and dried in an oven at 80 ° C. for 3 minutes to remove the solvent. Then, the coating layer 12 was formed. The thickness of the coating layer 12 after drying was 4.5 to 5.0 μm including in-plane variation.

  After the surface of the coating layer 12 was subjected to corona discharge treatment at an intensity of 280 W, a pressure-sensitive adhesive layer 14 (Lintec Corp.) formed on a polyethylene terephthalate (PET) film subjected to a release treatment to a thickness of 25 μm. ): P-3132, hereinafter referred to as “pressure-sensitive adhesive with release film”, and the PET film as the support is referred to as “release film”), and pressure-sensitive adhesive layer 14 is formed. A plurality of polarizing plates 300 were obtained. The thickness of the polarizing plate 300 was 95 μm excluding the release film.

<Evaluation of polarizing plate>
The release film on the pressure-sensitive adhesive layer is peeled off from the polarizing plate 300 with the pressure-sensitive adhesive layer prepared above, and the pressure-sensitive adhesive layer 14 side is bonded to soda glass to prepare a glass bonding sample. The treatment was performed at 50 ° C. and 5 atm for 20 minutes.

Next, after the glass-bonded sample was subjected to a thermal shock test as shown below, the glass-bonded sample was taken out and its appearance was evaluated. As a result, cracking did not occur in the polarizer 11.
Thermal shock test condition 1: Exposed to -35 ° C for 30 minutes.
Condition 2: Immediately after the treatment of Condition 1, transfer to 85 ° C. dry condition and expose for 30 minutes.
The treatment under the above conditions 1 and 2 was taken as one cycle, and 100 cycles were performed.

<Production and evaluation of liquid crystal display device>
6 is a cross-sectional view illustrating the configuration of the liquid crystal display device manufactured in Example 1. FIG. 7 is a diagram illustrating the absorption axis of the polarizer and the slow axis of the liquid crystal cell (no voltage applied) in the liquid crystal display device illustrated in FIG. It is a figure which shows the relationship with the time, ie, the orientation direction of the liquid crystal molecule at the time of black display, and so on. FIG. 7 shows the absorption axis A of the polarizer 11 on the viewing side, the slow axis B of the liquid crystal cell 31, and the absorption axis C of the polarizer 11 on the backlight side.

  A commercially available IPS mode liquid crystal television (manufactured by Hitachi, Ltd .: Wooo 7000) was disassembled, and all optical layers such as a polarizing plate and a retardation plate were peeled off, and the liquid crystal cell was taken out. The polarizing plate 300 produced above was bonded to the upper and lower sides of the obtained liquid crystal cell 31 in a configuration as shown in FIG. After assembling the liquid crystal television again, the color angle from all directions is measured using a commercially available viewing angle measuring device (ELDIM: EZ-contrast) with black displayed, and the viewing angle is used as an index of optical characteristics. Characteristics were evaluated.

[Comparative Example 1]
FIG. 8 is a cross-sectional view showing the configuration of the liquid crystal display device manufactured in Comparative Example 1, and FIG. 9 shows the relationship between the absorption axis of the polarizer and the slow axis of the liquid crystal cell in the liquid crystal display device shown in FIG. FIG. FIG. 9 shows the absorption axis A of the polarizer 11 on the viewing side, the slow axis B of the liquid crystal cell 31, and the absorption axis C of the polarizer 11 on the backlight side.

  A polarizing plate formed by forming a 40 μm-thick triacetyl cellulose film as a protective layer 13 on one side of a 25 μm-thick polarizer 11 was subjected to corona discharge treatment at an intensity of 280 W on the surface opposite to the protective layer 13. Thereafter, the same pressure-sensitive adhesive with a release film as that used in Example 1 was attached to obtain a plurality of polarizing plates on which the pressure-sensitive adhesive layer 14 was formed. The thickness of the polarizing plate was 90 μm excluding the release film.

  The release film on the pressure-sensitive adhesive layer is peeled off from the polarizing plate with the pressure-sensitive adhesive layer prepared above, and the pressure-sensitive adhesive layer side is bonded to soda glass to prepare a glass-bonded sample. Treated for 20 minutes at 5 atm.

  Next, after the glass-bonded sample was subjected to the thermal shock test described in Example 1, the glass-bonded sample was taken out and the appearance was evaluated. As a result, many cracks occurred in the polarizer 11.

  Moreover, the polarizing plate with a pressure-sensitive adhesive layer produced above was bonded to the upper and lower sides of the liquid crystal cell 31 obtained by the same method as in Example 1 in the configuration as shown in FIG. After assembling the liquid crystal television again, the viewing angle characteristics in a state where black was displayed were evaluated by the same method as in Example 1.

[Comparative Example 2]
10 is a cross-sectional view showing the configuration of the liquid crystal display device manufactured in Comparative Example 2. FIG. 11 shows the relationship between the absorption axis of the polarizer and the slow axis of the liquid crystal cell in the liquid crystal display device shown in FIG. FIG. FIG. 11 shows the absorption axis A of the polarizer 11 on the viewing side, the slow axis B of the liquid crystal cell 31, and the absorption axis C of the polarizer 11 on the backlight side.

  It was used in Example 1 after performing a corona discharge treatment at an intensity of 280 W on one side of a polarizing plate in which a 40 μm thick triacetyl cellulose film was formed as a protective layer 13 on both sides of a 25 μm thick polarizer 11. The same pressure-sensitive adhesive with a release film as was attached to obtain a plurality of polarizing plates on which the pressure-sensitive adhesive layer 14 was formed. The thickness of the polarizing plate was 130 μm excluding the release film.

  The release film on the pressure-sensitive adhesive layer is peeled off from the polarizing plate with the pressure-sensitive adhesive layer prepared above, and the pressure-sensitive adhesive layer side is bonded to soda glass to prepare a glass-bonded sample. Treated for 20 minutes at 5 atm.

  Next, after the glass-bonded sample was subjected to the thermal shock test described in Example 1, the glass-bonded sample was taken out and the appearance was evaluated. As a result, cracking did not occur in the polarizer 11.

  Moreover, the polarizing plate with a pressure-sensitive-type adhesive layer produced above was bonded together on the upper and lower sides of the liquid crystal cell 31 obtained by the method similar to Example 1 by the structure as shown in FIG. After assembling the liquid crystal television again, the viewing angle characteristics in a state where black was displayed were evaluated by the same method as in Example 1.

  FIG. 12 shows the xy chromaticity indicating the evaluation result of the color of the liquid crystal television manufactured in Example 1 when the liquid crystal display is viewed by changing the tilt angle from the normal direction and the azimuth angles of the screen up, down, left, and right. FIG. 13 is a graph showing the evaluation results of the color of the liquid crystal television manufactured in Comparative Example 1 when the liquid crystal display is viewed by changing the tilt angle from the normal direction and the azimuth angles of the screen up, down, left, and right. 14 is an xy chromaticity diagram shown in FIG. 14. FIG. 14 shows the color of the liquid crystal television manufactured in Comparative Example 2 when the liquid crystal display is viewed by changing the tilt angle from the normal direction and the azimuth angles of the screen up, down, left, and right. It is xy chromaticity figure which shows the evaluation result of.

  In these xy chromaticity diagrams, the horizontal axis is the x-axis and the vertical axis is the y-axis, the outer closed curve is a monochromatic light locus representing the stimulus value of monochromatic light, and the largest point of x at the right end is the wavelength of 780 nm. The highest point of y at the upper end corresponds to a wavelength near 520 nm, and the lowest point of y at the lower left corresponds to a wavelength of 380 nm. The vicinity of (x = 0.33, y = 0.33) corresponds to white, and generally the lower right side in the outer closed curve corresponds to red, the upper side corresponds to green, and the lower left side corresponds to blue. The collection of points on the inside is the actual measurement data, and the inclination angle from the normal is in the range of 0 to 80 degrees, and the right direction of the screen is 0 degrees and the azimuth angle is in the range of 0 to 360 degrees. The chromaticity measurement data is plotted as it is varied. It means that the smaller the area of the collection of points representing this measurement data, the smaller the color change due to the viewing angle.

  From the results shown in FIGS. 12 to 14, the liquid crystal television manufactured in Example 1 and Comparative Example 1 has little angle dependency on the color and is excellent in viewing angle characteristics, while the liquid crystal television manufactured in Comparative Example 2 The color change greatly depending on the viewing angle, and the viewing angle characteristics were inferior.

  The above results are summarized in Table 1.

  From the above results, in Comparative Example 1 in which neither a protective layer nor a coating layer was formed between the polarizer and the liquid crystal cell, the polarizing plate was as thin as 90 μm, and the optical characteristics of the liquid crystal display device could be secured. It can be seen that cracking occurred in the polarizer in the thermal shock test, and the durability of the polarizing plate was not sufficiently obtained. In Comparative Example 2 in which protective layers were formed on both sides of the polarizer, although the durability of the polarizing plate could be ensured, the thickness of the polarizing plate was as thick as 130 μm, and the optical characteristics of the liquid crystal display device could not be sufficiently ensured. I understand that. On the other hand, in Example 1 in which the coating layer was formed on one surface of the polarizer and the protective layer was formed on the other surface, the thickness of the polarizing plate was as thin as 95 μm, and the durability of the polarizing plate and the liquid crystal It can be seen that the optical characteristics of the display device can be secured satisfactorily. From these results, it was confirmed that the polarizing plate according to the present invention gave excellent optical characteristics when mounted on a liquid crystal television as an example of a liquid crystal display device, and was thin and excellent in durability.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The polarizing plate according to the present invention has good optical characteristics when mounted on a liquid crystal display device, particularly an IPS mode liquid crystal display, and has excellent durability against environmental changes. Moreover, since the thickness of the polarizing plate can be designed to be thinner than before, the present invention can be suitably applied to a thin liquid crystal display device.

It is sectional drawing which shows the example of a structure of the polarizing plate which concerns on this invention. It is sectional drawing which shows the example of a structure of the polarizing plate which concerns on this invention. It is sectional drawing which shows the example of a structure of the polarizing plate which concerns on this invention. It is sectional drawing which shows the example of a structure of the optical member which concerns on this invention. It is sectional drawing which shows the example of a structure of the principal part about the liquid crystal display device of another form which concerns on this invention. 3 is a cross-sectional view illustrating a configuration of a liquid crystal display device manufactured in Example 1. FIG. It is a figure which shows the relationship between the absorption axis of the polarizer in the liquid crystal display device shown in FIG. 6, and the slow axis of a liquid crystal cell. 6 is a cross-sectional view illustrating a configuration of a liquid crystal display device manufactured in Comparative Example 1. FIG. It is a figure which shows the relationship between the absorption axis of the polarizer and the slow axis of a liquid crystal cell in the liquid crystal display device shown in FIG. 11 is a cross-sectional view illustrating a configuration of a liquid crystal display device manufactured in Comparative Example 2. FIG. It is a figure which shows the relationship between the absorption axis of a polarizer and the slow axis of a liquid crystal cell in the liquid crystal display device shown in FIG. It is xy chromaticity diagram which shows the evaluation result of the color eye | rate when the inclination angle from a normal line direction and the azimuth angle of a screen up, down, left and right are changed variously about the liquid crystal television produced in Example 1. FIG. It is xy chromaticity diagram which shows the evaluation result of the color eye when the liquid crystal television produced by the comparative example 1 changes the inclination angle from a normal direction and the azimuth angle of a screen up, down, left and right variously. It is xy chromaticity diagram which shows the evaluation result of the color eye when the liquid crystal television produced by the comparative example 2 changes the inclination angle from a normal direction and the azimuth angle of a screen up, down, right and left is variously viewed.

Explanation of symbols

  100, 200, 300 Polarizing plate, 11 Polarizer, 12 Coating layer, 13 Protective layer, 14 Pressure sensitive adhesive layer, 21 Optical layer, 31 Liquid crystal cell, 400 Optical member, 500 Liquid crystal display device.

Claims (9)

A polarizer, and a coating layer formed on at least one side of the polarizer,
The coating layer comprises a composition comprising a water-soluble resin (A) and a water-soluble organometallic compound (B) comprising at least one selected from a water-soluble organic titanium compound and a water-soluble organic zirconium compound. A polarizing plate which is a formed layer. The coating layer is formed on one side of the polarizer,
The polarizing plate according to claim 1, wherein a protective layer made of a transparent resin film is further formed on a surface opposite to the surface on which the coating layer of the polarizer is formed.   The polarizing plate according to claim 1, wherein the transparent resin film is made of a resin selected from a cellulose resin, a cyclic olefin resin, and a chain olefin resin.   The polarizing plate according to claim 1, wherein the water-soluble resin (A) is a polyvinyl alcohol-based resin. The water-soluble organometallic compound (B) is an organic titanium compound, and the following formulas (1) and (2):
(HO) ₂ Ti [OCH (CH ₃ ) COOH] ₂ (1)
(C ₃ H ₇ O) ₂ Ti [OCH ₂ CH ₂ N (CH ₂ CH ₂ OH) ₂ ] ₂ (2)
The polarizing plate in any one of Claims 1-4 which consists of 1 or more types selected from the compound represented by these.   The polarizing plate in any one of Claims 1-5 whose thickness of the said coating layer exists in the range of 1-20 micrometers.   The polarizing plate according to claim 1, wherein a pressure-sensitive adhesive layer is further formed so as to face the polarizer with the coating layer interposed therebetween.   An optical member comprising a laminate in which the polarizing plate according to claim 1 and an optical layer are laminated. The polarizing plate according to claim 7 is formed on at least one surface of the liquid crystal cell,
A liquid crystal display device, wherein the polarizing plate is bonded to the liquid crystal cell by the pressure-sensitive adhesive layer.

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