TWI690738B - Composite polarizing plate and liquid crystal panel using the same - Google Patents

Abstract

This invention provides a composite polarizing plate with small decrease of polarization degree under high temperature and high humidity environment, and a liquid crystal panel with high thermal resistance and humidity resistance.

The composite polarizing plate are formed by laminating a first polarizing plate and a second polarizing plate, the first polarizing plate being formed by laminating a first protective film, a first polarizing film with a thickness of 15 μm or less, and a second protective film in this order, and the second polarizing plate being formed by laminating a third protective film, a second polarizing film with a thickness of 15 μm or less, and a fourth protective film in this order, wherein the absorption axis of the first polarizing film is roughly parallel to the absorption axis of the second polarizing film, and the second protective film and the third protective film between the first polarizing film and the second polarizing film satisfies the following formulae (1) and (2).

Re2(590)+Re3(590)≦15nm (1)

Rth2(590)+Rth3(590)≦20nm (2)

Description

Composite polarizing plate and liquid crystal panel using the polarizing plate

The present invention relates to a composite polarizing plate excellent in durability and a liquid crystal panel using the polarizing plate.

In recent years, liquid crystal display devices have taken advantage of the advantages of low power consumption, operation at low voltage, light weight, and thinness, and they have rapidly spread as information display devices for mobile phones, portable information terminals, computer monitors, and televisions. With the development of liquid crystal technology, liquid crystal display devices with multiple modes have been proposed, and the problems of liquid crystal display such as response speed and contrast, narrow viewing angle have been gradually solved. Under such circumstances, liquid crystal display devices are also developing in fields requiring high durability, such as in-vehicle applications. However, for severe endurance tests such as a temperature of 95°C and a temperature of 65°C/humidity of 95% (hereinafter referred to as 65°C/95%RH), when a conventional polarizing plate dyed with a polyvinyl alcohol-based resin using iodine is used There will be a problem that the degree of polarization is greatly reduced.

Japanese Unexamined Patent Publication No. 2002-072162 (Patent Document 1) discloses a configuration in which two polarizing plates are used on the light exit side of a projection-type display device, but in order to cool the polarizing plates, the two polarizing plates are spatially separated Way configuration. When the cooling gas is passed between two polarizing plates, Or when sapphire or crystal with high thermal conductivity is sandwiched between two polarizing plates, the reflection caused by the difference in refractive index is large at the interface of the air layer or crystal, and there is a problem of lowering the efficiency of light utilization.

In addition, Japanese Patent Laid-Open No. 10-133196 (Patent Document 2) discloses a composite polarizing plate for a liquid crystal projector in which a polarizing plate with improved heat resistance is directly laminated. However, in a polarizing plate in which a triacetyl cellulose film as a protective layer is disposed on both sides of a polarizing film having a thickness of 20 to 30 μm, the shrinking force of the polarizing film during heating is large, which may cause bending of the liquid crystal panel and polarizing plate Problems such as stripping. In addition, when using materials such as glass with a thermal conductivity of 0.8 W/m‧K or more as the protective layer of the polarizing film, there is a problem that the processing such as cutting is not easy and the production efficiency is low. Due to such circumstances, there is also a problem that it is not easy to impart functionality by providing a surface treatment layer on the surface of the composite polarizer.

In the above patent documents, although the countermeasures under high temperature environment are considered, there is still room for improvement. Therefore, when using a conventional polarizing plate in which polyvinyl alcohol resin is dyed with iodine, the polarizing plate is, for example, 65°C/95%RH The durability under high temperature and high humidity environment is still insufficient.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Publication No. 2002-072162

[Patent Document 2] Japanese Patent Laid-Open No. 10-133196

The object of the present invention is to provide a composite polarizing plate with a small degree of reduction in polarization degree under high temperature and high temperature and high humidity environments. Another object of the present invention is to provide a liquid crystal panel having high heat resistance and humidity resistance.

That is, according to the present invention, there is provided a composite polarizing plate which is formed by sequentially laminating a first polarizing plate and a second polarizing plate, the first polarizing plate sequentially laminating a first protective film, a first having a thickness of 15 μm or less The polarizing film and the second protective film are formed by sequentially stacking a third protective film, a second polarizing film with a thickness of 15 μm or less, and a fourth protective film, and the first polarizing plate and the second polarizing plate The absorption axes are slightly parallel, and the second protective film 2 and the third protective film existing between the first polarizing film and the second polarizing film satisfy the following formulas (1) and (2).

Re2(590)+Re3(590)≦15nm (1)

Rth2(590)+Rth3(590)≦20nm (2)

The first protective film, the second protective film, and the third protective film preferably each contain at least one selected from the group consisting of cellulose-based resins, olefin-based resins, and acrylic-based resins. Then, it is preferred that at least one of them has a moisture permeability of 200 g/m ² or less than ‧24hr.

In the composite polarizer of the present invention, it is preferred that the single polarizer has a single transmittance smaller than that of the second polarizer, and it is preferably the thickness of the first polarizer film and the thickness of the second polarizer film The difference is set to 5 μm or less. In addition, a composite polarizing plate is also provided, which is a surface opposite to the side where the second polarizing film is laminated on the fourth protective film in order to be attached to the liquid crystal panel With adhesive layer.

The fourth protective film preferably contains at least one selected from the group consisting of cellulose-based resins, polyolefin-based resins, and acrylic-based resins, and the phase difference in the thickness direction is preferably -10 to 10 nm.

Moreover, according to the present invention, there is also provided a liquid crystal display panel formed by laminating the above-mentioned composite polarizer on at least one side of a liquid crystal cell through an adhesive layer.

According to the present invention, a composite polarizing plate and a liquid crystal panel excellent in heat resistance and moisture heat durability can be obtained.

10‧‧‧Composite polarizer

11A‧‧‧The first polarizing film

11B‧‧‧The second polarizing film

12A‧‧‧The first protective film

12B‧‧‧4th protective film

13, 14‧‧‧ Adhesive layer

15‧‧‧Second protective film

16‧‧‧The third protective film

20‧‧‧Surface treatment layer

FIG. 1 is an example of a schematic cross-sectional view showing the layer structure of the composite polarizing plate of the present invention.

The layer structure of the composite polarizer 10 of the present invention will be described with reference to FIG. The composite polarizing plate 10 of the present invention is formed by laminating a first polarizing plate and a second polarizing plate, the first polarizing plate sequentially laminating a first protective film 12A, a first polarizing film 11A having a thickness of 15 μm or less, and a second protective film The second polarizing plate is formed by sequentially stacking a third protective film 16, a second polarizing film 11B and a fourth protective film 12B having a thickness of 15 μm or less. In the composite polarizing plate of the present invention, the second protective film 15 of the first polarizing plate and the third protective film 16 of the second polarizing plate are bonded via the adhesive layer 13 or the adhesive layer 13. It is also possible to form the surface treatment layer 20 on the surface of the first protective film 12A opposite to the bonding surface of the first polarizing film 11A use.

In the composite polarizing plate of the present invention, the first polarizing film 11A and the second polarizing film are arranged such that their absorption axes are slightly parallel. In this specification, slightly parallel means that the angle formed by the two is not strictly limited to 0°, but is, for example, within a range of 0±5°, preferably within a range of 0±3°.

The second protective film 15 and the third protective film 16 existing between the first polarizing film 11A and the second polarizing film 11B are used in which the sum of in-plane retardation values Re(590) at a wavelength of 590 nm is 15 nm or less. And the sum of the phase difference value Rth(590) in the thickness direction of the wavelength of 590 nm is 20 nm or less.

The first protective film 12A, the second protective film 15 and the third protective film 16 preferably contain at least one selected from the group consisting of cellulose resins, olefin resins and acrylic resins, respectively. In addition, it is preferable to use at least one of the first protective film, the second protective film, and the third protective film with a moisture permeability of 200 g/m ² ‧24 hr or less.

In order to suppress the shrinkage force of the polarizing plate under a high-temperature environment and a high-temperature and high-humidity environment, the thicknesses of the first polarizing film 11A and the second polarizing film 11B are both set to 15 μm or less. In addition, by making the single polarizer's monomer transmittance smaller than that of the second polarizer, the transmittance of the composite polarizer can be further improved.

Furthermore, the difference between the thickness of the first polarizing film 11A and the thickness of the second polarizing film 11B is preferably 5 μm or less. The fourth protective film 12B preferably contains at least one selected from the group consisting of cellulose resins, polyolefin resins, and acrylic resins. In addition, the thickness direction of the fourth protective film The phase difference value is preferably -10 to 10 nm.

In the composite polarizing plate 10, an adhesive layer 14 may be laminated on the second polarizing film or the second protective film. The composite polarizer can be bonded to the liquid crystal cell via the adhesive layer 14 to obtain a liquid crystal panel. Generally, the polarizing plate is attached to both sides of the liquid crystal cell, but the composite polarizing plate of the present invention can be suitably used for the viewing side and the back side of the liquid crystal display device or both.

In the composite polarizing plate of the present invention, after being placed in a high-temperature environment and a high-temperature and high-humidity environment, although the polarization degree of each polarizing plate may be reduced, the two polarizing plates are laminated in parallel polarized light (parallel nicol) Therefore, as far as the composite polarizing plate is concerned, the decrease in the degree of polarization can be suppressed.

Hereinafter, the members constituting the composite polarizing plate and the liquid crystal panel of the present invention will be described in detail in order while referring to the symbols attached to FIG. 1.

[Polarizing film]

The first polarizing film 11A and the second polarizing film 11B constituting the composite polarizing plate 10 can usually be manufactured through the following steps: a step of uniaxially extending the polyvinyl alcohol-based resin film; dichroism is used for the polyvinyl alcohol-based resin film The step of dyeing the pigment to adsorb the dichroic pigment; the step of treating the polyvinyl alcohol resin film adsorbed with the dichroic pigment with a boric acid aqueous solution to make it crosslink; and the crosslinking by the boric acid aqueous solution Steps of water washing after treatment.

The polyvinyl alcohol-based resin can be produced by saponifying the polyvinyl acetate-based resin. Polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, may also be vinyl acetate Copolymers of esters and other monomers copolymerizable with vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and propylene amides having an ammonium group.

The saponification degree of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may also be modified. For example, polyvinyl formal modified with polyvinyl aldehyde and polyvinyl acetal may be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000.

A film made of such a polyvinyl alcohol-based resin can be used as the original roll of polarizing film. The method of forming the polyvinyl alcohol resin film is not particularly limited, and the film can be formed by a known method. The film thickness of the original roll of polyvinyl alcohol-based resin is, for example, about 10 to 100 μm, preferably about 10 to 50 μm.

The one-axis extension of the polyvinyl alcohol-based resin film may be performed before dyeing by the dichroic dye, simultaneously with dyeing, or after dyeing. When the uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before boric acid treatment, or may be performed in boric acid treatment. Of course, it is also possible to perform uniaxial extension in the plural stages shown here. For uniaxial extension, the method of uniaxial extension between rollers with different peripheral speeds, or the method of uniaxial extension using hot rollers, etc. can be used. In addition, uniaxial stretching can be performed by dry stretching in the atmosphere, or by wet stretching in which a polyvinyl alcohol-based resin film is swelled using a solvent such as water. Yan The stretch ratio is usually about 3 to 8 times.

The dyeing of the polyvinyl alcohol-based resin film by the dichroic dye can be performed, for example, by immersing the polyvinyl alcohol-based resin film in the aqueous solution containing the dichroic dye. As for dichroic pigments, iodine and dichroic organic dyes can be specifically used. In addition, it is preferable that the polyvinyl alcohol-based resin film is swollen by immersion in water before dyeing.

When iodine is used as a dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide and dyeing is generally used. The content of iodine in the aqueous solution is usually about 0.01 to 1 part by weight relative to 100 parts by weight of water, and the content of potassium iodide is usually about 0.5 to 20 parts by weight relative to 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40°C. In addition, the immersion time (dyeing time) in the aqueous solution is usually about 20 to 1,800 seconds.

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

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

The polyvinyl alcohol resin film after boric acid treatment is usually washed with water. The water washing treatment can be performed by, for example, immersing the boric acid-treated polyvinyl alcohol-based resin film in water. For washing, a solution containing potassium iodide can be used. The temperature of the water in the washing process is usually about 5 to 40°C. In addition, the immersion time is usually about 1 to 120 seconds.

After washing with water, a drying treatment is applied to obtain a polarizing film. The drying process can be performed using a hot air dryer or a far-infrared heater. The drying temperature is usually about 30 to 100°C, preferably 50 to 80°C. The drying time is usually about 60 to 600 seconds, preferably 120 to 600 seconds. By drying, the moisture content in the polarizing film is reduced to a practical level. The moisture content is usually about 5 to 20% by weight, preferably 8 to 15% by weight. When the moisture content is less than 5% by weight, the flexibility of the polarizing film may be lost, and the film may be damaged or broken after drying. In addition, when the moisture content exceeds 20% by weight, the thermal stability tends to be insufficient.

According to the above method, a polarizing film obtained by aligning a dichroic dye with a polyvinyl alcohol-based resin film can be manufactured.

In addition, the stretching, dyeing, boric acid treatment, water washing step, and drying step of the polyvinyl alcohol resin film in the manufacturing process of the polarizing film can be performed according to the method described in Japanese Patent Application Laid-Open No. 2012-159778, for example. In the method described in this document, it is also useful to use a method of forming a polyvinyl alcohol-based resin layer that will become a polarizing film by applying a polyvinyl alcohol-based resin to a base film.

If the shrinkage force of the polarizing film in a high-temperature environment is to be suppressed to a low value, the thickness of the polarizing film is preferably 12 μm or less. From the viewpoint of giving good optical characteristics, the thickness of the polarizing film is usually 3 μm or more.

The thickness difference between the two polarizing films 11A and 11B is preferably 5 μm or less. More preferably, it is 3 μm or less. In this way, a polarizing film with a small thickness difference is used, whereby the first polarizing film 11A and the second polarizing film 11B can match the dimensional change in a high-temperature environment. Therefore, it is considered that the cracking of the polarizing film caused by the stress difference caused by the difference in thermal shrinkage of the two polarizing films is suppressed.

When the polarizing film is maintained at a temperature of 80°C for 240 minutes, it is preferable that the shrinkage force per 2 mm of the width in the absorption axis direction is 2 N or less. When the shrinkage force is greater than 2N, the amount of dimensional change in a high-temperature environment becomes larger and the shrinkage force of the polarizing film becomes larger, so the polarizing film tends to easily break or peel. When the stretching magnification is decreased or the thickness of the polarizing film is made thin, the shrinking force of the polarizing film tends to become 2N or less.

In addition, the difference in shrinkage force per 2 mm of the width of the two polarizing films in the absorption axis direction is preferably 1 N or less, more preferably 0.5 N or less. As described later, in the composite polarizer of the present invention, it is preferred that the second polarizer has a monomer transmittance greater than that of the first polarizer. Therefore, the shrinkage force of the two polarizing films may also be comparable Different, for example, the difference in contraction force may be 0.1 N or more.

[1st protective film, 2nd protective film, 3rd protective film]

The first protective film 12A, the second protective film 15, and the third protective film 16 used in the composite polarizing plate 10 may be composed of a transparent resin film. In particular, it is preferably composed of a material excellent in transparency, mechanical strength, thermal stability, moisture shielding properties, and the like. In this specification, the transparent resin film refers to a resin film having a monomer transmittance of 80% or more in the visible light region. The first protective film 12A, the second protective film 15 and the third protective film 16 may be the same protective film or different protective films, respectively.

For the first protective film 12A, the second protective film 15, and the third protective film 16, cellulose-based resins, chain polyolefin-based resins, cyclic polyolefin-based resins, acrylic resins, and polyamides can be used. Imine-based resins, polycarbonate-based resins, polyester-based resins, etc. are widely used in this field as films formed by conventional protective film forming materials.

As for the materials constituting the first protective film 12A, the second protective film 15 and the third protective film 16, for example, cellulose-based resins, polyolefin-based resins and acrylic resins are preferably used. Here, the so-called polyolefin resin includes chain polyolefin resin and cyclic polyolefin resin. Such resin films may be films made by melt extrusion of raw resin, one-axis stretched film obtained by transversely extending after film forming, and longitudinally stretched after film forming Then, the resulting biaxially stretched film is stretched laterally.

The cellulose-based resin may be an organic acid ester or mixed organic acid ester of cellulose in which a part or all of the hydrogen atoms in the hydroxyl groups of cellulose are substituted with acetyl, propyl and/or butyl acetyl groups. Examples include cellulose acetate, propionate, butyrate, mixed esters of these, and the like. Among them, triacetyl cellulose, diethyl cellulose, cellulose acetate propionate, cellulose acetate butyrate and the like are preferred.

The cyclic polyolefin resin is obtained, for example, by polymerizing cyclic olefin monomers such as norbornene and other cyclopentadiene derivatives in the presence of a catalyst. When such a cyclic polyolefin resin is used, it is easy to obtain a protective film having a predetermined phase difference value described later.

Examples of cyclic polyolefin resins include, for example, those obtained by a Diels-Alder reaction from cyclopentadiene and olefins or (meth)acrylic acid or its esters Resin obtained by carrying out ring-opening shift polymerization of norbornene or its derivatives as monomers and subsequent hydrogenation; borrowed from dicyclopentadiene and olefins or (meth)acrylic acid or its esters Tetracyclododecene or its derivative obtained by Diels-Adel reaction as a monomer for ring-opening shift polymerization, and resin obtained by subsequent hydrogenation; will be selected from norbornene, tetracyclo Dodecene, derivatives of these, and at least two monomers among other cyclic olefin monomers are similarly subjected to ring-opening shift copolymerization, and a resin obtained by subsequent hydrogenation; , Tetracyclododecene, or derivatives of such cyclic olefins, resins obtained by addition copolymerization with chain olefins and/or aromatic compounds having a vinyl group.

The cyclic polyolefin-based resin can be easily obtained on the market. If listed as examples of commercially available products, they are indicated by trade names, respectively: "TOPAS" manufactured by TOPAS ADVANCED POLYMERS GmbH and sold by POLYPLASTICS Co., Ltd. in Japan, and "ARTON (registered "Trademark)", "ZEONOR (registered trademark)" and "ZEONEX (registered trademark)" sold by Zeon Corporation, Japan, and "APEL (registered trademark)" sold by Mitsui Chemicals Corporation, etc.

Typical examples of chain polyolefin resins are polyethylene resins and polypropylene resins. Among them, it can be suitably used: a homopolymer of propylene; or a propylene-based comonomer copolymerizable with propylene (for example, ethylene) at a ratio of 1 to 20% by weight, preferably 3 to 10% by weight Copolymer copolymerized in a ratio of %.

The polypropylene-based resin may contain an alicyclic saturated hydrocarbon resin. By containing alicyclic saturated hydrocarbon resin, it becomes easy to adjust the phase difference value. Relative to the polypropylene-based resin, the content of the alicyclic saturated hydrocarbon resin is preferably set to 0.1 to 30% by weight, and the more preferable content is 3 to 20% by weight. When the content of the alicyclic saturated hydrocarbon resin is less than 0.1% by weight, the effect of adjusting the phase difference cannot be sufficiently obtained. On the other hand, when the content exceeds 30% by weight, the alicyclic resin may be generated from the protective film over time. There is doubt about saturated hydrocarbon resin bleed out.

Acrylic resins are typically polymers containing more than 50% by weight of methyl methacrylate units. The content of the methyl methacrylate unit is preferably 70% by weight or more, or 100% by weight.

Acrylic resins containing methyl methacrylate as the main component can be easily obtained on the market, and are indicated by their trade names, for example: "SUMIPEX (registered trademark)" sold by Sumitomo Chemical Co., Ltd., Mitsubishi Rayon Co., Ltd. “ACRYPET (registered trademark)” sold, “DELPET (registered trademark)” sold by Asahi Kasei Co., Ltd., “PARAPET (registered trademark)” sold by KURARAY Co., Ltd., Japan Catalyst Co., Ltd. "ACRYVIEWA (registered trademark)", etc. sold.

These resins can be formulated with suitable additives within the range of no loss of transparency. Examples of additives include antioxidants, ultraviolet absorbers, antistatic agents, slip agents, nucleating agents, anti-fogging agents, antiblocking agents, retardation reducing agents, stabilizers, and processing agents Additives, plasticizers, impact-resistant additives, matting agents, antibacterial agents, mildew inhibitors, etc. Antioxidants include, for example, phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, hindered amine-based light stabilizers, etc. In addition, one molecule may have both a phenol-based antioxidant structure and a phosphorus-based antioxidant. The compound antioxidant of the unit of antioxidant structure. Examples of the ultraviolet absorber include 2-hydroxybenzophenone-based ultraviolet absorbers, hydroxyphenylbenzotriazole-based ultraviolet absorbers, and benzoate-based ultraviolet shielding agents. The antistatic agent may be any of polymer type, oligomer type, and monomer type. Examples of the slip agent include higher fatty acid amides such as mustard amide and oleamide, higher fatty acids such as stearic acid, and salts thereof. Examples of the nucleating agent include polymer nucleating agents such as sorbitol-based nucleating agents, organic phosphate-based nucleating agents, and polyvinyl naphthenes. Examples of anti-caking agents include: spherical Or particles with a nearly spherical shape and can be used regardless of whether they are inorganic or organic. Examples of the retardation reducing agent include alicyclic saturated hydrocarbon resins added to polypropylene resins. These additives can also be used in combination.

As for the method of forming a film from the resin as described above, any suitable method may be appropriately selected. For example, the following method may be used: a solvent casting method in which a resin dissolved in a solvent is cast to a metal band or drum, and the solvent is dried and removed to obtain a film; and the resin is heated above its melting temperature, Kneading and extruding from the die, cooling to obtain the film melt extrusion method, etc. In the melt extrusion method, a single-layer film can be extruded, or a multi-layer film can also be extruded at the same time.

Films of these resins can be easily obtained from commercially available products. To cite examples of commercially available films, cellulose-based resin films are indicated by their trade names, respectively: "FUJITAC (registered trademark) TD" sold by FUJIFILM Co., Ltd. and KONICA MINOLTA Co., Ltd. "KONICA MINOLTA TAC FILM KC", etc. As for the cyclic olefin resin film, there are "ZEONOR series" sold by Zeon Co., Ltd., etc. As for the acrylic resin film, there are "ACRYPLEN series" sold by Mitsubishi Rayon Co., Ltd. and the like.

Furthermore, for the second protective film 15 and the third protective film 16, those satisfying the following formulas (1) and (2) are used. With such characteristics, it is possible to obtain a composite polarizing plate that suppresses depolarization between polarizing films and has a high degree of polarization.

Re2(590)+Re3(590)≦15nm (1)

Rth2(590)+Rth3(590)≦20nm (2)

Here, Re2 (590) is a phase difference value in the plane of the second protective film 15 with a wavelength of 590 nm, and Re3 (590) is a phase difference value in the plane of the third protective film 16 with a wavelength of 590 nm. In addition, Rth2(590) is the phase difference value Rth(590) in the thickness direction of the second protective film 15 at a wavelength of 590 nm, and Rth3(590) is the phase difference value in the thickness direction of the third protective film 16 at a wavelength of 590 nm Value Rth(590).

The phase difference value Rth in the thickness direction is a value obtained by subtracting the refractive index in the thickness direction from the in-plane average refractive index multiplied by the thickness of the film, and is defined by the following formula (a). In addition, the in-plane phase difference value Re is a value obtained by multiplying the in-plane refractive index difference by the thickness of the film, and is defined by the following formula (b).

Rth=[(n _x +n _y )/2-n _z ]×d (a)

Re=(n _x -n _y )×d (b)

In the formula, n _x is the refractive index in the x-axis direction (in-plane slow axis direction) of the film surface, n _y is the y-axis direction in the film surface (in-plane fast axis direction, and is orthogonal to the x axis in the plane) Direction), n _z is the refractive index in the z-axis direction (thickness direction) perpendicular to the film surface, and then d is the thickness of the film.

Here, the phase difference value may be in the range of about 500 to 650 nm near the center of visible light and a value at any wavelength, but in this specification, the phase difference value at a wavelength of 590 nm is used as a standard. The phase difference value Rth in the thickness direction and the in-plane phase difference value Re can be measured using various commercially available phase difference meters.

In order to set the phase difference between the second protective film 15 and the third protective film 16 to the above range, the following method can be selected: The method of stacking the film by offsetting the difference, or the method of stacking two films with the low phase difference. From the viewpoint of easy adjustment of the retardation value of the film, it is preferable to laminate two films with a low retardation value.

As a method of controlling the phase difference between the in-plane and thickness directions of the protective film to be within a predetermined range, a method may be mentioned in which the deformation remaining in the in-plane and thickness direction is reduced as much as possible when manufacturing the film. For example, in the above-mentioned solvent casting method, a method of alleviating the residual shrinkage deformation in the thickness direction generated when the casting resin solution is dried by heat treatment can be used. On the other hand, in the above-mentioned melt extrusion method, in order to prevent the extension of the resin film from the die to the cooling period, the distance from the die to the cooling drum can be reduced as much as possible, and the film can be controlled so as not to stretch The method of extrusion and the rotation speed of the cooling drum. In addition, as with the solvent casting method, a method of alleviating the deformation remaining in the obtained film by heat treatment can be used.

As for the phase difference value of the protective film produced in this way, the in-plane phase difference value is preferably 7 nm or less, more preferably 5 nm or less, and still more preferably 3 nm or less. The phase difference in the thickness direction is preferably 10 nm or less, more preferably 8 nm or less, and still more preferably 5 nm or less.

In addition, it is preferable that at least one of the first protective film 12A, the second protective film 15 and the third protective film 16 uses a transparent resin film having a moisture permeability of 200 g/m ² or less for ²⁴ hours.

The two protective films of the first protective film 12A, the second protective film 15 and the third protective film 16 may be transparent resin films having a moisture permeability of 200 g/m ^{2 and} ‧24 hr or less. Examples include: The protective film 12A and the second protective film 15 have a combination of moisture permeability of 200 g/m ² ‧24hr or less, and the first protective film 12A and the third protective film 16 have a combination of moisture permeability of 200 g/m ² ‧24hr or less. The protective film 15 and the third protective film 16 are a combination of moisture permeability of 200 g/m ^{2 and} ≤24 hr.

In addition, all protective films of the first protective film 12A, the second protective film 15, and the third protective film 16 may use transparent resin films having a moisture permeability of 200 g/m ² or less and ‧24 hr.

If the moisture permeability of the protective film is to be 200 g/m ² or less than ‧24 hr, it is preferable to use a film containing an olefin resin or acrylic resin.

If the moisture permeability of the protective film is 200g/m ² ‧24hr or less, the deterioration of the heat and humidity of the polarizing films of the first polarizing film 11A and the second polarizing film 11B or both of them can be suppressed, so it can become even in a high humidity environment A polarizer that reduces the degree of polarization. The better moisture permeability is less than 150g/m ² ‧24hr, and even better is 100g/m ² ‧24hr.

[Surface treatment layer 20 of the first protective film 12A]

The first protective film 12A may have a surface treatment layer 20 on the surface opposite to the surface to which the first polarizing film 11A is bonded. The surface treatment layer 20 may include, for example, a hard coat layer having a fine surface uneven shape. The hard coat layer preferably has a pencil hardness harder than H. When the pencil hardness is H or less than H, the surface is easy to be injured, and the visibility of the liquid crystal display device becomes worse when injured. The pencil hardness is obtained in accordance with JIS K 5600-5-4: 1999 "General Test Methods for Paints-Part 5: Mechanical Properties of Coating Films-Section 4: Scratch Hardness (Pencil Method)" to use the hardness It is indicated by the hardness of the hardest pencil that does not cause any damage when the pencil is scratched.

The first protective film 12A having the surface treatment layer 20 preferably has a haze value in the range of 0.1 to 45%, and more preferably in the range of 5 to 40%. When the haze value is greater than 45%, although the reflection of external light can be reduced, the density of the black display screen will be reduced. Also, when the haze value is less than 0.1%, sufficient anti-glare performance cannot be obtained, and the external light is reflected on the screen, which is not good. Here, the haze value is obtained in accordance with JIS K 7136: 2000 "Method for determining the haze of plastic-transparent materials".

The hard coat layer with fine surface unevenness can be formed by the following method: a method of forming a coating film containing organic fine particles or inorganic fine particles on the surface of the resin film; and forming a coating containing or not containing organic fine particles or inorganic fine particles After the film is applied, a method of pressing with a roller having an uneven shape, such as an emboss method. Such a coating film can be obtained, for example, by applying a coating solution (curable resin composition) containing a binder component made of a curable resin and organic fine particles or inorganic fine particles on the surface of the resin film, etc. form.

For the inorganic fine particles, for example, silica, colloidal silica, alumina, alumina sol, aluminosilicate, alumina-silica composite oxide, kaolin, talc, mica, calcium carbonate, calcium phosphate, etc. can be used. As for the organic fine particles, cross-linked polyacrylic acid particles, methyl methacrylate/styrene copolymer resin particles, cross-linked polystyrene particles, cross-linked polymethyl methacrylate particles, polysiloxane resins can be used Resin particles such as particles or polyimide particles.

The binder component used to disperse inorganic fine particles or organic fine particles should be selected from materials that will become high hardness (hard coating) That's it. As the binder component, photo-curable resin, thermosetting resin, electron beam curable resin, etc. can be used, but from the viewpoint of productivity, hardness of the surface treatment layer 20 obtained, etc., it is preferably photo-curable Sexual resin. For photocurable resins, commercially available ones can be used as appropriate. For example, multifunctional acrylates such as trimethylolpropane triacrylate and neopentyl alcohol tetraacrylate can be used alone or in combination of two or more, and "IRGACURE (registered trademark) 907" and "IRGACURE (registered trademark)" can be mixed therein. 184" or "Lucirin (registered trademark) TPO" (both are trade names sold by BASF) and other photopolymerization initiators, which are made into photocurable resins. When a photocurable resin is used, a resin composition can be obtained by dispersing inorganic fine particles or organic fine particles therein, which is coated on a resin film, and by irradiating light, the inorganic fine particles dispersed in the binder resin or Hard coating of organic particles.

For the multifunctional acrylate constituting the photocurable resin, in addition to the monomer types such as trimethylolpropane triacrylate and neopentyl tetraacrylate, the urethane acrylate can also be used , Polyol (meth)acrylate, or oligomer type (meth)acrylic oligomer having an alkyl group containing two or more hydroxyl groups.

The urethane acrylate here is prepared, for example, using (meth)acrylic acid and/or (meth)acrylate, polyol, and diisocyanate. Specifically, a method of preparing a hydroxy (meth)acrylate having at least one hydroxy group from (meth)acrylic acid and/or (meth)acrylate and a polyol, and reacting it with a diisocyanate To make urethane acrylate. Such (meth)acrylic acid and/or (meth)acrylate, Polyol and diisocyanate may be used alone or in combination of two or more. In addition, various additives can be added depending on the purpose.

Examples of the (meth)acrylate used in the manufacture of urethane acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, ( Alkyl (meth)acrylates such as isopropyl meth)acrylate and butyl (meth)acrylate; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate.

The polyol used in the manufacture of urethane acrylate is also a compound having at least two hydroxyl groups in the molecule. Specific examples are: ethylene glycol, trimethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol , 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 2,2,4-trimethyl-1,3-pentanediol, 3-methyl 1,5-pentanediol, neopentyl glycol hydroxytrimethylacetate, cyclohexane dimethylol, 1,4-cyclohexanediol, spiroglycol, tricyclic Decane dimethylol, hydrogenated bisphenol A, ethylene oxide addition bisphenol A, propylene oxide addition bisphenol A, trimethylolethane, tri-dimethylolpropane, glycerin, 3- Methylpentane-1,3,5-triol, neopentaerythritol, dipentaerythritol, tripentaerythritol, glucose, etc.

Similarly, the diisocyanates used in the manufacture of urethane acrylates can be aromatic, aliphatic or alicyclic diisocyanates. Specific examples include: tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2,4-toluene diisocyanate, 1,5-naphthalene diisocyanate, diphenyl-4, 4'-diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, xylylene diisocyanate, trimethyl Hexamethylene diisocyanate, diphenylmethane-4,4’-diisocyanate, and hydrides of compounds with aromatic rings among these.

Specific examples of polyhydric alcohol (meth)acrylates that can become polyfunctional acrylates include: neopentaerythritol di(meth)acrylate, neopentaerythritol tri(meth)acrylate, neopentyl Tetraol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, etc. These can be used individually or in combination. Furthermore, various additives may be added as needed. The polyol (meth)acrylate preferably contains neopentyl tetraacrylate and neopentyl tetraacrylate. These can be copolymers or mixtures.

In addition, other (meth)acrylic oligomers having an alkyl group containing two or more hydroxyl groups that can become polyfunctional acrylates include, for example, those having 2,3-dihydroxypropyl groups. (Meth)acrylic oligomer, or (meth)acrylic oligomer having 2-hydroxyethyl and 2,3-dihydroxypropyl.

Specific examples of the photopolymerization initiator constituting the photocurable resin include: 2,2-dimethoxy-2-phenylacetophenone, acetophenone, benzophenone, xanthone (xanthone), 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, benzoin propyl ether, benzil dimethyl ketal , N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane- 1-ketones, other thioxanthone compounds, etc.

The photo-curable resin can be used in a state of being dissolved in a solvent as necessary. As for the solvent, ethyl acetate and butyl acetate can be used Headed by various organic solvents.

In addition, the photocurable resin may contain a leveling agent, and for example, a fluorine-based or polysiloxane-based leveling agent may be mentioned. Examples of the polysiloxane-based leveling agent include reactive polysiloxane, polydimethylsiloxane, polyether-modified polydimethylsiloxane, and polymethylalkylsiloxane. It is preferably a reactive polysiloxane and a silicone leveling agent. By using a reactive polysilicone leveling agent to impart sliding properties to the surface of the hard coat layer, excellent scratch resistance can be maintained for a long period of time. On the other hand, when the silicone leveling agent is used, the film forming ability can be improved.

Examples of the leveling agent of reactive polysiloxane include those having a siloxane bond, and an acrylic group or a hydroxyl group. Specific examples include the following copolymers. (a) Copolymer of dimethylsiloxane/3-propenyl-2-hydroxypropoxypropylsiloxane/2-propenyl-3-hydroxypropoxypropylsiloxane, ( b) Copolymer of dimethylsiloxane/hydroxypropylsiloxane/tris(ω-isocyanatoalkyl)isocyanuric acid/aliphatic polyester, (c)dimethylsiloxane /Polyalkylene glycol alkyl siloxane with acrylate end/Copolymer of polyalkylene glycol alkyl siloxane with hydroxy end.

Specific examples of commercially available reactive polysiloxanes are listed under trade names, including: "GRANDIC (registered trademark) PC-4100" sold by DIC Corporation, and sold by BYK Chemie Japan Co., Ltd. The "BYK-UV3500", "BYK-UV3750", "BYK-370", "BYK-371", "BYK-375", "BYK-377" and so on.

By using the acrylic adhesive component (adhesive resin) as exemplified above, the adhesion to the protective film can be improved while Improve the mechanical strength, and can form a surface treatment layer 20 that can effectively prevent surface injuries.

When the hard coat layer with fine surface unevenness is provided by the imprint method, an unhardened hard coat layer is formed on the resin film, and the hard coat layer is hardened while pressing the mold formed with the fine unevenness to make The shape of the mold can be transferred to the hard coat layer. The transfer of the shape of the mold to the hard coat layer is preferably performed by imprinting. For imprinting, it is preferably a UV imprinting method using an ultraviolet curable resin which is a type of photocurable resin. When the fine surface unevenness is formed by the imprint method, the hard coat layer may or may not contain inorganic or organic fine particles.

In the UV imprinting method, an ultraviolet-curable resin layer is formed on the surface of the protective film, and the ultraviolet-curable resin layer is pressed against the concave-convex surface of the mold while curing, whereby the concave-convex surface of the mold is transferred to the ultraviolet-curable resin Floor. Specifically, the ultraviolet curable resin is coated on the resin film, and the ultraviolet curable resin is irradiated from the resin film side to cure the ultraviolet curable resin while the coated ultraviolet curable resin is in close contact with the uneven surface of the mold. The resin film formed with the cured ultraviolet curable resin layer is peeled from the mold, thereby transferring the shape of the mold to the ultraviolet curable resin. The type of ultraviolet curable resin is not particularly limited, and for example, the aforementioned ones can be used. Furthermore, instead of the ultraviolet curable resin, a visible light curable resin that can be cured with visible light having a longer wavelength than ultraviolet light by appropriately selecting a photopolymerization initiator can be used.

The thickness of the surface treatment layer 20 is not particularly limited, but it is preferably in the range of 2 to 30 μm, more preferably in the range of 3 to 30 μm. Surface treatment layer 20 When the thickness is less than 2 μm, it becomes difficult to obtain sufficient hardness, and the surface tends to be easily injured. In addition, when the thickness is greater than 30 μm, there is a tendency that the first protective film 12A curls easily due to the hardening shrinkage of the surface treatment layer, and productivity decreases.

The first protective film 12A, as described above, is preferably provided with a haze by a hard coat layer, but it can also be provided by dispersing inorganic or organic fine particles in the protective film while forming the hard coat layer. Specific examples of the inorganic or organic fine particles used for this purpose are the same as those disclosed above.

The first protective film 12A may be subjected to various additional surface treatments such as antistatic treatment, antifouling treatment, or antibacterial treatment in addition to the aforementioned antiglare treatment (haze imparting treatment) that also serves as a hard coat layer, and It can form a coating layer made of liquid crystal compound, its high molecular weight compound and so on. Furthermore, in addition to surface treatment, the antistatic function can also be imparted to other parts of the polarizing plate such as an adhesive layer.

[4th protective film 12B]

For the fourth protective film 12B, cellulose resin, chain polyolefin resin, cyclic polyolefin resin, acrylic resin, polyimide resin, polycarbonate resin, polyester can be used Films made of materials such as resins are widely used in the field as materials for forming conventional protective films. The fourth protective film 12B may be the same film as the first protective film 12A, the second protective film 15, and the third protective film 16, or may be different films. The fourth protective film 12B is preferably a cellulose-based resin, polyolefin-based resin, or acrylic-based resin from the viewpoint of easy adjustment of the phase difference value and easy acquisition. The so-called polyolefin-based resin system includes chain-like poly Olefin resin and cyclic polyolefin resin.

For the fourth protective film 12B, it is preferable to use the same film with a low phase difference value as the second protective film 15 and the third protective film 16 are suitable for use.

When the liquid crystal cell is in an In-Plane Switching (IPS) mode, in order not to damage the wide viewing angle characteristic originally possessed by the IPS mode liquid crystal cell, the fourth protective film 12B preferably has a phase difference value Rth in the thickness direction of − The range of 10 to 10 nm.

As a method of adjusting the phase difference value Rth in the thickness direction of the resin film in the range of -10 to 10 nm, a method of reducing the deformation remaining in the thickness direction as much as possible when producing the film can be cited. For example, in the above-mentioned solvent casting method, a method of alleviating the residual shrinkage deformation in the thickness direction generated when the casting resin solution is dried by heat treatment can be used. On the other hand, in the above-mentioned melt extrusion method, in order to prevent the extension of the resin film from the die to the cooling period, the distance from the die to the cooling drum can be reduced as much as possible, and the film can be controlled so as not to stretch The method of extrusion and the rotation speed of the cooling drum. In addition, as with the solvent casting method, a method of alleviating the deformation remaining in the obtained film by heat treatment can be used.

[Lamination of polarizing film and protective film]

The bonding of the first protective film 12A and the first polarizing film 11A, the bonding of the first polarizing film 11A and the second protective film 15, the third protective film 16 and the second polarizing film can be performed by an adhesive or an adhesive The bonding of 11B and the bonding of the second polarizing film 11B and the fourth protective film 12B.

In this specification, the first polarizing film 11A and the second polarizing film 11B may be collectively referred to as a polarizing film, and the first protective film 12A, the second protective film 15, the third protective film 16, and the fourth protective film 12B Collectively referred to as protective film.

The thickness of the adhesive layer to which the polarizing film and the protective film are bonded can be set to about 0.01 to 30 μm, preferably 0.01 to 10 μm, more preferably 0.05 to 5 μm. As long as the thickness of the adhesive layer is within this range, no floating or peeling occurs between the laminated protective film and the polarizing film, and practically no adhesive force can be obtained. The thickness of the adhesive layer for bonding the polarizing film and the protective film can be set to about 5 to 50 μm, preferably 5 to 30 μm, and more preferably 10 to 25 μm.

For the formation of the adhesive layer, an appropriate and appropriate adhesive can be used according to the type and purpose of the adherend, and an anchor coating agent can also be used as needed. Examples of the adhesive include solvent adhesives, emulsion adhesives, pressure-sensitive adhesives, rewet adhesives, polycondensation adhesives, solventless adhesives, film adhesives, and heat. Melt adhesives, etc.

As one of the preferable adhesives, water-based adhesives can be cited, even if the adhesive component is dissolved or dispersed in water. If an example of an adhesive component soluble in water is given, there is a polyvinyl alcohol-based resin. In addition, if an example of an adhesive component that can be dispersed in water is cited, there are urethane resins having a hydrophilic group. The water-based adhesive can be prepared by mixing such an adhesive component with additional additives formulated as necessary in water. Examples of commercially available polyvinyl alcohol-based resins that can be used as water-based adhesives include: carboxy-modified polymer sold by KURARAY Co., Ltd. "KL-318" of vinyl alcohol, etc.

The water-based adhesive may contain a cross-linking agent if necessary. Examples of crosslinking agents include amine compounds, aldehyde compounds, methylol compounds, water-soluble epoxy resins, isocyanate compounds, and polyvalent metal salts. When a polyvinyl alcohol-based resin is used as an adhesive component, an aldehyde compound including glyoxal, a methylol compound including methylolmelamine, a water-soluble epoxy resin, and the like can be preferably used as a crosslinking agent. Here, the water-soluble epoxy resin may be, for example, a polyamide epoxy resin obtained by reacting polyamide polyamine with epichlorohydrin. The polyamide polyamine belongs to diethylenetriamine or triethylenetetramine The reactant of polyalkylene polyamine such as amine and dicarboxylic acid such as adipic acid. Examples of commercially available water-soluble epoxy resins include "Sumirez Resin (registered trademark) 650 (30)" sold by Takaoka Chemical Industry Co., Ltd.

The polarizing plate can be obtained by applying an aqueous adhesive on the bonding surface of the polarizing film and/or the protective film bonded to the polarizing film, and bonding the two, followed by drying treatment. Before performing the adhesion, it is also effective if the protective film is previously subjected to easy adhesion treatment such as saponification treatment, corona discharge treatment, plasma treatment, or primer treatment to improve the wettability. The drying temperature can be set to, for example, about 50 to 100°C. After the drying process, it is preferably aged at a temperature slightly higher than room temperature, for example, at a temperature of about 30 to 50° C. for about 1 to 10 days, in terms of further improving the adhesion.

As another preferable adhesive, a hardening adhesive composition containing an epoxy compound hardened by irradiation or heating of active energy rays can be cited. Here, those having at least two epoxy groups in the molecule of the curable epoxy compound. At this time, the adhesion of the polarizing film and the protective film can be The coating layer of the adhesive composition is irradiated with active energy rays or heat is applied to harden the curable epoxy compound contained in the adhesive. The curing of epoxy compounds is generally carried out by cationic polymerization of epoxy compounds. In addition, from the viewpoint of productivity, the hardening is preferably performed by irradiation of active energy rays.

From the viewpoint of weather resistance, refractive index, cationic polymerizability, etc., the epoxy compound contained in the curable adhesive composition is preferably one that does not contain an aromatic ring in the molecule. Examples of epoxy compounds containing no aromatic ring in the molecule include hydrogenated epoxy compounds, alicyclic epoxy compounds, and aliphatic epoxy compounds. An epoxy compound suitable for use in such a hardenable adhesive composition has been described in detail in Japanese Patent Laid-Open No. 2004-245925, for example, but it is also outlined here.

Hydrogenated epoxy compound may be a glycidyl group obtained by subjecting an aromatic polyhydroxy compound which is a raw material of an aromatic epoxy compound to a nuclear hydrogenation reaction obtained by selective nuclear hydrogenation reaction in the presence of a catalyst and under pressure Etherified. Examples of aromatic polyhydroxy compounds that are raw materials of aromatic epoxy compounds include bisphenols such as bisphenol A, bisphenol F, and bisphenol S; phenol novolac resins and cresols Novolak resins such as novolak resins and hydroxybenzaldehyde phenol novolak resins; polyfunctional compounds such as tetrahydroxydiphenylmethane, tetrahydroxybenzophenone, and polyvinylphenol. Epoxypropyl etherification can be carried out by subjecting such an aromatic polyhydroxy compound to a nuclear hydrogenation reaction and reacting the resulting nuclear hydrogenated polyhydroxy compound with epichlorohydrin. Examples of suitable hydrogenated epoxy compounds include hydrogenated glycidyl ethers of bisphenol A.

An alicyclic epoxy compound is a compound having at least one epoxy group bonded to an alicyclic ring in the molecule. "Epoxy group bonded to an alicyclic ring" means a bridged oxygen atom -O- in the structure represented by the following formula, in which m is an integer of 2 to 5.

The compound formed by bonding one or more hydrogen atoms in (CH ₂ ) _m in the formula to other chemical structures can become an alicyclic epoxy compound. In addition, one or more hydrogen atoms in (CH ₂ ) _m forming an alicyclic ring may be appropriately substituted with a linear alkyl group such as methyl or ethyl. Among the alicyclic epoxy compounds, epoxy compounds having an oxabicyclohexane ring (m=3 in the above formula) and an oxacyclocycloheptane ring (m=4 in the above formula) show excellent adhesion Sex, so it can be used better. Hereinafter, specific examples of the alicyclic epoxy compound will be disclosed. Here, the name of the compound is listed first, and then the corresponding chemical formulas are indicated respectively. The compound name and the corresponding chemical formula are appended with the same symbol.

A: 3,4-epoxycyclohexanecarboxylic acid 3,4-epoxycyclohexyl methyl ester, B: 3,4-epoxy-6-methylcyclohexanecarboxylic acid 3,4-epoxy -6-methylcyclohexyl methyl ester, C: ethylidene bis(3,4-epoxycyclohexane formate), D: bis(3,4-epoxycyclohexylmethyl adipate) ) Ester, E: bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, F: diethylene glycol bis(3,4-epoxycyclohexyl methyl ether), G: ethylene glycol bis(3,4-epoxycyclohexyl methyl ether), H: 2,3,14 ,15-Diepoxy-7,11,18,21-tetraoxatrispiro[5.2.2.5.2.2]icosane, I: 3-(3,4-epoxycyclohexyl)-8 ,9-epoxy-1,5-dioxaspiro[5.5]undecane, J: 4-vinylcyclohexene dioxide, K: limonene dioxide, L: bis(2,3- Epoxycyclopentyl) ether, M: dicyclopentadiene dioxide, etc.

A:

B:

C:

D:

E:

F:

G:

H:

I:

J:

K:

L:

M:

The aliphatic epoxy compound may be a polyglycidyl ether of an aliphatic polyhydric alcohol or an alkylene oxide adduct thereof. More specific and For example, diglycidyl ether of propylene glycol; diglycidyl ether of 1,4-butanediol; diglycidyl ether of 1,6-hexanediol; tricyclic glycerol Oxypropyl ether; triglycidoxypropyl ether of trimethylolpropane; obtained by adding alkylene oxide (such as ethylene oxide and propylene oxide) to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin Polyglycidyl ether of polyether polyol (such as diglycidyl ether of polyethylene glycol), etc.

In the curable adhesive composition, one type of epoxy compound may be used alone, or two or more types may be used in combination. Among them, the epoxy compound preferably contains an alicyclic epoxy compound having at least one epoxy group bonded to an alicyclic ring in the molecule.

The epoxy compound used in the curable adhesive composition generally has an epoxy equivalent in the range of 30 to 3,000 g/equivalent, and the epoxy equivalent is preferably in the range of 50 to 1,500 g/equivalent. When an epoxy compound having an epoxy equivalent of less than 30 g/equivalent is used, there is a possibility that the flexibility of the polarizing plate after hardening may decrease, or the strength may subsequently decrease. On the other hand, a compound having an epoxy equivalent of more than 3,000 g/equivalent may reduce the compatibility with other components contained in the adhesive composition.

From the viewpoint of reactivity, it is preferable to use cationic polymerization as the hardening reaction of the epoxy compound. For this reason, it is preferable to mix a cationic polymerization initiator in the hardenable adhesive composition containing an epoxy compound. The cationic polymerization initiator generates a cationic species or a Lewis acid by irradiation or heating of active energy rays such as visible rays, ultraviolet rays, X-rays, and electron beams, and starts the polymerization reaction of epoxy groups. From the viewpoint of workability, it is preferable to impart potentiality to the cationic polymerization initiator. the following, The cationic polymerization initiator that generates cationic species or Lewis acid by the irradiation of active energy rays and initiates the polymerization reaction of epoxy groups is called "photocationic polymerization initiator", and the cationic species or The cationic polymerization initiator that causes the Lewis acid to start the polymerization reaction of the epoxy group is called "thermal cationic polymerization initiator".

Using a photo-cationic polymerization initiator and curing the adhesive composition by irradiation of active energy rays, it can be cured at normal temperature and humidity, and the deformation due to the heat resistance or expansion of the polarizing film can be reduced It is advantageous in terms of the need for the protective film and the polarizing film to be adhered well. In addition, the photo-cationic polymerization initiator exerts a catalytic effect by light, so even if it is mixed with an epoxy compound, its storage stability and workability are still excellent.

Examples of the photo-cationic polymerization initiator include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic cerium salts, and iron-allene complexes. The formulation amount of the photocationic polymerization initiator is usually 0.5 to 20 parts by weight, preferably 1 part by weight or more, and preferably 15 parts by weight or less with respect to 100 parts by weight of the epoxy compound. When the amount of the photocationic polymerization initiator is less than 0.5 parts by weight relative to 100 parts by weight of the epoxy compound, the curing becomes insufficient, and the mechanical strength and subsequent strength of the cured product tend to decrease. On the other hand, when the amount of the photocationic polymerization initiator exceeds 20 parts by weight with respect to 100 parts by weight of the epoxy compound, the ionic substance in the hardened material increases, so that the hygroscopicity of the hardened material becomes high and there is durability Possibility of reduced performance.

When using photo-cationic polymerization initiator, The agent composition may further contain a photosensitizer if necessary. By using a light sensitizer, the reactivity of cationic polymerization can be improved, and the mechanical strength and subsequent strength of the hardened product can be improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo compounds, diazo compounds, halogen compounds, and photoreducible dyes. When blending the photosensitizer, the amount of the photosensitizer is preferably in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the curable adhesive composition. In addition, in order to increase the curing rate, sensitizing aids such as naphthoquinone derivatives can be used.

On the other hand, examples of the thermal cationic polymerization initiator include benzyl alkane salt, thienium salt, tetrahydrothienium salt, benzyl ammonium, pyridinium salt, hydrazinium salt, Carboxylic acid esters, sulfonic acid esters, amide imines, etc.

The hardening adhesive composition containing an epoxy compound is preferably hardened by photocationic polymerization as described above, but the above thermal cationic polymerization initiator may also be present and hardened by thermal cationic polymerization, and light may be used together Cationic polymerization and thermal cationic polymerization. When photocationic polymerization and thermal cationic polymerization are used together, the curable adhesive composition preferably contains both a photocationic polymerization initiator and a thermal cationic polymerization initiator.

In addition, the curable adhesive composition may further contain a compound that promotes cationic polymerization, such as an oxetane compound and a polyol compound. Oxetane compounds are compounds with a 4-membered cyclic ether in the molecule. When blending the oxetane compound, the amount of the curable adhesive composition is usually 5 to 95% by weight, preferably 5 to 50% by weight. In addition, the polyol compound may include ethylene glycol, hexamethylene glycol, and polyethylene glycol. Alkylene glycol or its oligomer, polyester polyol, polycaprolactone polyol, polycarbonate polyol, etc. When blending a polyol compound, the amount of the curable adhesive composition is usually 50% by weight or less, preferably 30% by weight or less.

Furthermore, the curable adhesive composition may contain other additives such as: ion trapping agent, antioxidant, chain transfer agent, sensitizer, tackifier, thermoplastic resin, filler without compromising its adhesiveness , Flow regulator, plasticizer, defoamer, etc. Examples of the ion trapping agent include inorganic compounds including powdered bismuth-based, antimony-based, magnesium-based, aluminum-based, calcium-based, titanium-based, and mixtures of these, and antioxidants may be used. Examples include hindered phenol antioxidants.

After applying the hardening adhesive composition containing an epoxy compound to the adhesive surface of the polarizing film or the protective film, or the adhesive surface of both, the surface coated with the adhesive is bonded, and the active energy ray is irradiated or heated By hardening the uncured adhesive layer, the polarizing film and the protective film can be adhered. As for the coating method of the adhesive, various coating methods such as doctor blade, wire bar, die coater, comma coater, and gravure coater can be used.

This hardenable adhesive composition can basically be used as a solventless adhesive that does not substantially contain a solvent. However, each coating method has its own optimum viscosity range. Therefore, a solvent may be included to adjust the viscosity. The solvent is preferably an organic solvent that does not degrade the optical properties of the polarizing film and dissolves the components including epoxy compounds, such as hydrocarbons represented by toluene and esters represented by ethyl acetate. .

When the adhesive composition is hardened by irradiation of active energy rays, the aforementioned various types of active energy rays can be used. However, from the viewpoint of ease of operation and ease of control of the amount of light to be irradiated, it is preferable to use ultraviolet rays. The irradiation intensity and irradiation amount of active energy rays (such as ultraviolet rays) are within a range that does not affect various optical properties such as the polarization degree of the polarizing film, and various optical properties including the transparency and phase difference characteristics of the protective film. Appropriately decided in a way that maintains moderate productivity.

When the adhesive composition is hardened by heat, it can be heated by a generally known method. Generally, the thermal cationic polymerization initiator formulated in the curable adhesive composition is heated above the temperature at which cationic species are generated and Lewis acid branches, and the specific heating temperature is, for example, about 50 to 200°C.

[Adhesive layer 13 used for lamination of polarizing plates]

For the adhesive layer 13 used for the lamination of the first polarizing plate and the second polarizing plate, an adhesive or an adhesive can be used. When an adhesive is used as the adhesive layer 13, the same adhesive as that used for bonding the polarizing film and the protective film may be used, or it may be an adhesive different from the adhesive used for bonding the polarizing film and the protective film. For another form, it is also preferable to use an adhesive for the lamination of the first polarizing plate and the second polarizing plate.

[Adhesive layer 13]

The adhesive layer 13 used for the lamination of the first polarizing plate and the second polarizing plate may be one that has excellent optical transparency and excellent adhesion characteristics including moderate wettability, agglomeration, and adhesion, but it is preferably further Those with excellent durability. Specifically, the adhesive forming the adhesive layer 13 is preferably It is an adhesive containing acrylic resin (acrylic adhesive).

The acrylic resin contained in the acrylic adhesive is a resin mainly composed of alkyl acrylate such as butyl acrylate, ethyl acrylate, isooctyl acrylate, and 2-ethylhexyl acrylate. The acrylic resin is usually copolymerized with a polar monomer. Polar single system refers to a compound having a polymerizable unsaturated bond and a polar functional group. Here, the polymerizable unsaturated bond is generally derived from a (meth)acryloyl group, and the polar functional group may be a carboxyl group, Hydroxy, amide, amine, epoxy, etc. Specific examples of polar monomers include: (meth)acrylic acid, (meth)acrylic acid 2-hydroxypropyl ester, (meth)acrylic acid 2-hydroxyethyl ester, (meth)acrylamide, (method Group) 2-N,N-dimethylaminoethyl acrylate, glycidyl (meth)acrylate, etc.

In addition, in the acrylic adhesive, the crosslinking agent is usually formulated together with the acrylic resin. Representative examples of the crosslinking agent include isocyanate compounds having at least two isocyanate groups (-NCO) in the molecule.

Adhesives can be further formulated with various additives. Suitable additives include silane coupling agents and antistatic agents. The silane coupling agent is effective in improving the adhesion with glass. Antistatic agents are effective in reducing or preventing the generation of static electricity.

The adhesive layer 13 can be formed by preparing an adhesive composition obtained by dissolving the adhesive component in an organic solvent, and applying it directly to the first polarizing plate or the second polarizing plate, and A method of drying and removing the solvent; or, applying the above-mentioned adhesive composition to the release-treated surface of the base film formed of a resin film subjected to release treatment, and drying and removing the solvent to form an adhesive layer , Attach it to the first polarizer Or the second polarizer, and transfer the adhesive layer. When the adhesive layer 13 is formed on the first polarizing plate or the second polarizing plate by the former direct coating method, a resin film (also called a separator) subjected to a release treatment is usually attached to the surface ), temporarily protect the surface of the adhesive layer until it is used. From the viewpoint of the operability of the adhesive composition belonging to the organic solvent solution, the latter transfer method is mostly used. In this case, the substrate film that has been subjected to the release treatment used for the initial formation of the adhesive layer is attached. Attached to the polarizer, it can be used as a separator directly, which is also suitable.

Before laminating the first polarizing plate or the second polarizing plate via an adhesive or an adhesive, it is also useful to perform corona treatment, plasma treatment, etc. on the protective film surface or the adhesive surface in advance.

[Adhesive layer 14]

The adhesive layer 14 formed on the surface of the fourth protective film 12B that is opposite to the bonding surface of the second polarizing film 11B, as long as it is excellent in optical transparency and includes moderate wettability, cohesiveness, adhesion, etc. adhesion Those having excellent characteristics may be sufficient, but those having further excellent durability and the like are preferably used. Specifically, for the adhesive forming the adhesive layer, an adhesive containing an acrylic resin (acrylic adhesive) can be preferably used. Specifically, the same adhesive layer as that used when laminating the first polarizing plate and the second polarizing plate can be used. It may be the same as or different from the adhesive layer used when laminating the adhesive layer 14, the first polarizing plate, and the second polarizing plate.

The adhesive layer 14 may contain various additives in the same manner as the adhesive layer 13. Among them, the adhesive layer 14 preferably contains an antistatic agent. Generally speaking, when attaching the polarizing plate to the liquid crystal cell through the adhesive layer, the Covering and peeling off the surface protective film (separator) temporarily protected by the adhesive layer until bonding, and then bonded to the liquid crystal cell, but due to the static electricity generated when the surface protective film is removed, liquid crystal is generated The alignment of the liquid crystal in the cell is poor. This phenomenon sometimes leads to poor display of the liquid crystal display device. In terms of reducing or preventing the generation of such static electricity, it is effective to mix antistatic agents in the adhesive.

When the fourth protective film 12B and the adhesive layer 14 are bonded together, it is also useful to perform corona treatment, plasma treatment, etc. on the surface where the fourth protective film 12B and the adhesive layer 14 are to be bonded.

[Manufacturing method of composite polarizer]

The method of manufacturing the composite polarizing plate of the present invention is not particularly limited, for example: manufacturing the polarizing plate A formed by laminating the first protective film 12A, the first polarizing film 11A, and the second protective film 15; and by the third The polarizing plate B in which the protective film 16, the second polarizing film 11B, and the fourth protective film 12B are laminated. Then, the adhesive layer 13 is formed on the second protective film 15 of the polarizing plate A or the third protective film 16 of the polarizing plate B. If the polarizing plate A and the polarizing plate B produced in this way are laminated via the adhesive layer 13 and rolled to roll, a composite polarizing plate can be produced. Further, the adhesive layer 14 is formed on the fourth protective film 12B, and a composite polarizing plate with an adhesive can be obtained. The composite polarizer with an adhesive can be attached to the liquid crystal cell via the adhesive layer 14.

As described above, when two polarizing plates are laminated to manufacture a composite polarizing plate, the monomer transmittance of the first polarizing plate is preferably 38.0 to 43.0%, and more preferably 40.0 to 42.5%. The second single polarizing plate preferably has a single penetration rate of 40.0 To 45.0%, more preferably 41.0 to 43.0%. In addition, the polarization degree of the first polarizing plate and the polarization degree of the second polarizing plate are preferably 99.90% or more, more preferably 99.95% or more.

In this way, in the composite polarizing plate of the present invention, it is preferable that the second polarizing plate has a monomer transmittance greater than that of the first polarizing plate. The difference between the monomer transmittance of the first polarizer and the monomer polarizer of the second polarizer is preferably 0.1% or more, more preferably more than 0.2%, or 0.4% or more. Although the upper limit of the difference is not particularly limited, it is usually 5% or less, preferably 2% or less, and more preferably 1% or less.

In addition, another method can also be preferably used: a method of manufacturing the composite polarizing plate 10 by using the solvent-free adhesive for the polarizing plate A and the polarizing plate B and bonding them roll-to-roll.

The polarizing degree of the composite polarizing plate of the present invention obtained by the above manufacturing method is preferably 99.95% or more, more preferably 99.99% or more, and still more preferably 99.995% or more.

In addition, the composite polarizing plate of the present invention suppresses the decrease in the degree of polarization even after being put into a 95°C oven for 1000 hours of heat resistance test. For example, the polarization degree of the composite polarizer after the aforementioned heat resistance test may be 99.95% or more, or 99.99% or more. From another point of view, the degree of reduction in the degree of polarization before and after the heat resistance test can be 0.010% or less in the composite polarizer of the present invention, preferably 0.005% or less, and more preferably 0.003% the following.

In addition, the composite polarizing plate of the present invention suppresses the polarization even after being put into an oven at 65°C and 95% RH for 1,000 hours. Decrease in luminosity. For example, the polarization degree of the composite polarizing plate after the humidity and heat resistance test may be 99.95% or more, or 99.99% or more. From another point of view, the magnitude of the degree of decrease in the degree of polarization before and after the humidity heat resistance test can be 0.010% or less in the composite polarizer of the present invention, preferably 0.005% or less, and more preferably 0.003 %the following.

[LCD unit]

The liquid crystal cell has two cell substrates and a liquid crystal layer sandwiched between the substrates. The unit substrate is generally composed of glass, but it may also be a plastic substrate. In addition, the liquid crystal cell used in the liquid crystal panel of the present invention can be composed of various objects used in the field.

[LCD panel]

The liquid crystal panel can be manufactured by bonding the composite polarizer 10 to the liquid crystal cell through the adhesive layer 14. Generally, the polarizing plate is attached to both sides of the liquid crystal cell, but the composite polarizing plate of the present invention is suitable for use on the viewing side and the back side of the liquid crystal display device or both sides thereof.

(Example)

In the following, the examples are listed to further specifically explain the present invention, but the present invention is not limited to these examples. In the example, "parts" and "%" indicating the content or usage amount are the basis of weight when there is no special note. In addition, the measurement of each physical property in the following example is performed according to the following method.

(1) Determination of thickness:

It was measured using a digital micrometer "MH-15M" made by Nikon Corporation.

(2) In-plane phase difference and thickness phase difference Determination:

Using the phase difference meter "KOBRA (registered trademark)-WPR" based on the principle of the parallel polarization rotation method manufactured by Oji Measuring Equipment Co., Ltd., the in-plane phase difference value and the thickness direction at a wavelength of 590 nm are measured at a temperature of 23°C Phase difference value.

(3) Determination of shrinkage force of polarizing film:

Using Super Cutter manufactured by Ogino Seiki Co., Ltd., and cutting the polarizing film so that the absorption axis direction becomes the long axis, it is cut into fragments of 2 mm in width×50 mm in length. The obtained short strip-shaped polarizing film was used as a shrinkage force measurement sample. A thermomechanical analyzer ["TMA/6100" manufactured by Hitachi High-Tech Science Co., Ltd.] was used to set the shrinkage force measurement sample so that the distance between the chucks was 10 mm, and the test piece was placed in a 20°C room After leaving for a sufficient time, the temperature of the sample chamber was increased from 20°C to 80°C in 1 minute, and the temperature of the sample chamber was set to be maintained at 80°C after the temperature was raised. After the temperature was raised and left for 4 hours, the shrinkage force in the longitudinal direction of the measurement sample was measured in an environment of 80°C. In this measurement, the static load was set to 0 mN, and a SUS probe was used for the jig.

(4) Determination of the polarization degree of the polarizing plate and the penetration rate of the monomer:

A spectrophotometer with an integrating sphere ["V7100" manufactured by Japan Spectroscopy Co., Ltd., 2 degree field of view; C light source] was used for measurement.

(5) Determination of moisture permeability:

The moisture permeability is measured in accordance with JIS Z 0208. The temperature and humidity conditions are set at 40°C and 90%RH.

[Manufacture example 1] Production of polarizing film 1

A polyvinyl alcohol film with a thickness of 30 μm (average degree of polymerization of about 2400 and saponification degree of 99.9 mol% or more) is stretched dry and uniaxially stretched by about 4 times, and further immersed in 40°C pure water for 40 seconds while maintaining tension ，Immersion in an aqueous solution with a weight ratio of iodine/potassium iodide/water of 0.052/5.7/100 at 28℃ for 30 seconds for dyeing treatment. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide/boric acid/water of 11.0/6.2/100 at 70°C for 120 seconds. Then, after washing with 8°C pure water for 15 seconds, it was dried at 60°C for 50 seconds and then at 75°C for 20 seconds while maintaining the tension of 300N, to obtain a thickness of 12 μm with iodine adsorbed on the polyvinyl alcohol film. Absorption polarizing film. The shrinkage force of the obtained polarizing film was measured and found to be 2.0N.

[Manufacture example 2] Production of polarizing film 2

A polyvinyl alcohol film with a thickness of 20 μm (average degree of polymerization of about 2400 and saponification degree of 99.9 mol% or more) is dry-extended and uniaxially stretched to about 4 times, and further immersed in 40°C pure water for 40 seconds while maintaining tension After that, it was immersed in an aqueous solution having a weight ratio of iodine/potassium iodide/water of 0.052/5.7/100 at 28°C for 30 seconds to perform dyeing treatment. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide/boric acid/water of 11.0/6.2/100 at 70°C for 120 seconds. Then, after washing with 8°C pure water for 15 seconds, it was dried at 60°C for 50 seconds and then at 75°C for 20 seconds while maintaining the tension of 300N. The thickness of the iodine adsorbed on the polyvinyl alcohol film was 7 μm. Absorption polarizing film. The shrinkage force of the obtained polarizing film was measured and found to be 1.7N.

[Manufacture example 3] Production of polarizing film 3

Modified polyvinyl alcohol powder with an average polymerization degree of 1100 and a saponification degree of 99.5 mol% acetoacetylate [made by Nippon Synthetic Chemical Industry Co., Ltd. Trade name "GOHSEFIMER (registered trademark) Z-200"] dissolved in 95°C hot water to prepare a 3% strength aqueous solution. In this aqueous solution, a water-soluble polyamide epoxy resin [trade name "Sumirez Resin (manufactured by Taoka Chemical Industry Co., Ltd. made by Taoka Chemical Industry Co., Ltd.) is mixed as a cross-linking agent at a ratio of 5 parts relative to the solid content of polyvinyl alcohol in 6 parts. Registered trademark) 650", an aqueous solution with a solid concentration of 30%], used as a coating liquid for undercoating. Then, after corona treatment was applied to the base film (polypropylene film having a thickness of 110 μm and a melting point of 163° C.), the coating liquid for undercoating was applied to the corona treatment surface using a microgravure coater. Then, it was dried at 80°C for 10 minutes to form an undercoat layer with a thickness of 0.2 μm.

Then, a polyvinyl alcohol powder with an average polymerization degree of 2400 and a saponification degree of 98.0 to 99.0 mol% [trade name "PVA124" obtained from KURARAY Co., Ltd.] was dissolved in hot water at 95°C to prepare an 8% concentration polyvinyl alcohol Water solution. The obtained aqueous solution was applied to the undercoat layer of the above-mentioned base film using a lip coater at room temperature, and dried at 80°C for 20 minutes to prepare the base film/undercoat layer/polyvinyl alcohol layer. Laminated film.

Next, the obtained laminated film was extended at a temperature of 160° C. with a free end longitudinal axis extending 5.8 times. The overall thickness of the laminated stretched film thus obtained was 28.5 μm, and the thickness of the polyvinyl alcohol layer was 5.0 μm.

The obtained laminated stretched film was immersed in an aqueous solution having a water/iodine/potassium iodide weight ratio of 100/0.35/10 at 26°C for 90 seconds for dyeing, and then washed with pure water at 10°C. Then, the laminated stretched film was immersed in an aqueous solution having a water/boric acid/potassium iodide weight ratio of 100/9.5/5 at 76°C for 300 seconds to crosslink polyvinyl alcohol. Then, it was washed with pure water at 10°C for 10 seconds, and finally dried at 80°C for 200 seconds. Through the above operations, made in On the polypropylene base film, a polarizing laminate film formed of a polarizing film 3 having a thickness of 5 μm formed by a polyvinyl alcohol layer with iodine adsorbed and aligned is formed. The obtained polarizing film was peeled from the substrate and the shrinkage force was measured. The result was 1.45N.

[Manufacture example 4] Production of polarizing film 4

A polyvinyl alcohol film with a thickness of 60 μm (average degree of polymerization of about 2400, saponification degree of 99.9 mol% or more) is dry-stretched and uniaxially stretched to about 4 times, and further immersed in 40°C pure water for 40 seconds while maintaining tension After that, it was immersed in an aqueous solution having a weight ratio of iodine/potassium iodide/water of 0.052/5.7/100 at 28°C for 30 seconds to perform dyeing treatment. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide/boric acid/water of 11.0/6.2/100 at 70°C for 120 seconds. Then, after washing with pure water at 8°C for 15 seconds, it was dried at 60°C for 50 seconds and then at 75°C for 20 seconds while maintaining the tension of 300N. The thickness of the iodine adsorbed on the polyvinyl alcohol film was 23 μm. Absorption polarizer. The shrinkage force of the obtained polarizing film was measured and found to be 3.1N.

[Production Example 5] Preparation of water-based adhesive

Dissolve 3 parts by weight of carboxy-modified polyvinyl alcohol [trade name "KL-318" obtained from KURARAY Co., Ltd.] with respect to 100 parts by weight of water, and add 1.5 parts by weight of water-soluble epoxy to the aqueous solution Polyamide epoxy-based additives for resins [trade name "Sumirez Resin (registered trademark) 650(30)", an aqueous solution with a solid content concentration of 30% by weight obtained from Tiangang Chemical Industry Co., Ltd.], to prepare an aqueous adhesive.

[Production Example 6] Preparation of adhesive containing curable epoxy resin composition

It will be equivalent to the above formula D bis as an alicyclic epoxy resin 100 parts of bis(3,4-epoxycyclohexylmethyl) adipate of epoxycyclohexyl methyl ester of carboxylic acid, diglycidyl group of hydrogenated bisphenol A as hydrogenated epoxy resin After mixing 25 parts of ether and 2.2 parts of 4,4'-bis(diphenyldihydrothio) diphenyl sulfide bis(hexafluorophosphate) as a photocationic polymerization initiator, defoaming was performed to obtain Adhesive A containing a curable epoxy resin composition. Furthermore, the photo-cationic polymerization initiator is formulated in the form of a 50% by mass propylene carbonate solution.

[Adhesives A, B]

Prepare the following 2 adhesives.

Adhesive A: A sheet-shaped adhesive with a thickness of 25 μm ["P-3132" manufactured by Lintec Corporation]

Adhesive B: Sheet adhesive with a thickness of 15 μm ["P-0082" manufactured by Lintec Corporation]

[Protection film A, B, C, D]

Prepare the following 4 protective films.

Protective film A: Triacetyl cellulose film with hard coating made by KONICA MINOLTA Co., Ltd.; 25KCHCN-TC (thickness 32μm, moisture permeability=430g/m ² ‧24hr)

Protective film B: cyclic polyolefin resin film made by Zeon Co., Ltd. of Japan; ZF14-013 (thickness 13 μm, in-plane retardation value at a wavelength of 590 nm = 0.8 nm, and thickness direction retardation at a wavelength of 590 nm = 3.4 nm , Permeability = 30g/m ² ‧24hr)

Protective film C: Triacetyl cellulose film manufactured by KONICA MINOLTA Co., Ltd.; KC2CT (thickness 20 μm, phase difference in the plane of wavelength 590 nm = 1.2 nm, phase difference in thickness direction of the wavelength 590 nm = 1.3 nm, moisture permeability =1660g/m ² ‧24hr)

Protective film D: Triacetyl cellulose film made by KONICA MINOLTA Co., Ltd.; KC2UAW (thickness 25μm, moisture permeability=1207g/m ² ‧24hr)

[Production Example 7]

(Production of polarizing plate A)

The saponification treatment is performed on the protective film A, and the corona treatment is applied on the protective film B. In order to make the triacetyl cellulose surface of the protective film A and the corona-treated surface of the protective film B become the bonding surface with the polarizing film 1, respectively, the protective film A, the polarizing film 1, the protective film B The water-based adhesive is then obtained to obtain polarizing plate A. The monomer penetration rate of polarizing plate A is 42.0%.

[Production Example 8]

(Production of polarizing plate B)

Saponification treatment is performed on the protective film A and the protective film C. The protective film A, the polarizing film 1, and the protective film C are adhered with an aqueous adhesive so that the triacetyl cellulose surface of the protective film A and the triacetyl cellulose surface of the protective film C become the bonding surface with the polarizing film 1. To obtain polarizing plate B. Polarizer B has a monomer penetration rate of 42.0%.

[Production Example 9]

(Production of polarizing plate C)

The protective film C is saponified, and the protective film B is subjected to corona treatment. The protective film C, the polarizing film 1, and the protective film B are adhered by water in such a manner that the triacetyl cellulose surface of the protective film C and the corona-treated surface of the protective film B become the bonding surface with the polarizing film 1. Next, the polarizing plate C is obtained. Polarizer C has a monomer penetration rate of 42.0%.

[Production Example 10]

(Production of polarizing plate D)

The protective film C is saponified, and the protective film B is subjected to corona treatment. The protective film C, the polarizing film 2 and the protective film B were adhered with an aqueous adhesive so that the corona-treated surface became the bonding surface with the polarizing film 2 to obtain a polarizing plate D. Polarizer D has a monomer penetration rate of 42.3%.

[Production Example 11]

(Production of polarizing plate E)

Saponification treatment was performed on two protective films C. The polarizing plate E was obtained by bonding the protective film C, the polarizing film 2, and the protective film C with an aqueous adhesive so that the triacetyl cellulose surface of the protective film C became the bonding surface with the polarizing film 2. Polarizer E has a monomer penetration rate of 42.5%.

[Production Example 12]

(Production of polarizing plate F)

The saponification treatment is performed on the protective film A, and the corona treatment is applied on the protective film B. The protective film A, the polarizing film 2, and the protective film B were formed in such a manner that the triacetyl cellulose surface of the protective film A and the corona-treated surface of the protective film B became the bonding surfaces with the polarizing film 2, respectively. The water-based adhesive is then obtained to obtain polarizing plate F. The monomer transmittance of the polarizing plate F is 42.0%.

[Production Example 13]

(Production of polarizer G)

The protective film D is saponified, and the protective film B is corona-treated. So that the triacetyl cellulose surface of the protective film D and the protective film B are energized The halo-treated surface becomes a bonding surface with the polarizing film 2, and the protective film D, the polarizing film 2, and the protective film B are bonded with an aqueous adhesive to obtain a polarizing plate G. The monomer penetration rate of the polarizing plate G is 42.3%.

[Production Example 14]

(Production of polarizing plate H)

Saponification treatment is performed on the protective film A, and corona treatment is applied to the bonding surface of the protective film B and the polarizing film 3. Only the base film was peeled from the polarizing laminate film produced in Production Example 3 to obtain the polarizing film 3. The protective film A, the polarizing film 3, and the protective film B are formed in such a manner that the triacetyl cellulose surface of the protective film A and the corona-treated surface of the protective film B become the bonding surfaces with the polarizing film 3, respectively. The water-based adhesive is then obtained to obtain a polarizing plate H. The monomer penetration rate of the polarizing plate H is 41.2%.

[Production Examples 15 to 22]

Except that the water-based adhesive used in Production Examples 7 to 14 was changed to an adhesive containing a curable epoxy resin composition, polarizing plates I to P were produced in the same manner. At the time of bonding, an ultraviolet irradiation device (lamp: Fusion D lamp, integrated light amount 1500 mJ/cm ² ) with a belt conveyor was used to irradiate the ultraviolet rays, and left at room temperature for 1 hour.

The individual transmittances of the manufactured polarizing plates are as follows.

In addition, () shows the polarizing plate made with the water-based adhesive of the same structure.

Production Example 15 Polarizing Plate I (Polarizing Plate A): Monomer transmission rate is 42.0%

Production Example 16 Polarizing Plate J (Polarizing Plate B): Monomer transmittance is 42.0%

Production Example 17 Polarizing Plate K (Polarizing Plate C): Monomer transmittance is 42.0%

Production Example 18 Polarizing plate L (polarizing plate D): the single transmittance is 42.3%

Production Example 19 Polarizing Plate M (Polarizing Plate E): The single transmittance is 42.5%

Production Example 20 Polarizing Plate N (Polarizing Plate F): Monomer transmission rate is 42.0%

Production Example 21 Polarizing Plate O (Polarizing Plate G): Monomer transmission rate is 42.3%

Production Example 22 Polarizing Plate P (Polarizing Plate H): Monomer transmission rate is 41.2%

[Production Example 23]

(Production of polarizer Q)

A polarizing plate was produced in the same manner except that the polarizing film 1 in the polarizing plate A was changed to the polarizing film 4. The monomer penetration rate of the polarizing plate Q is 42.0%.

[Production Example 24]

(Production of polarizer R)

A polarizing plate was produced in the same manner except that the polarizing film 2 in the polarizing plate D was changed to the polarizing film 4. The monomer penetration rate of the polarizing plate Q is 42.3%.

[Example 1]

Using the adhesive B, the protective film B in the polarizing plate A is bonded to the protective film B in the polarizing plate D in such a manner that the absorption axes of the polarizing plates are parallel to each other. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film C side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. Heat-resistant The polarization degree after the test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 2]

Using the adhesive B, the protective film B in the polarizing plate A and the protective film C in the polarizing plate E are laminated in such a manner that the absorption axes of the polarizing plates are parallel to each other. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. Adhesive A was bonded to the protective film C side of the composite polarizing plate thus obtained. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.8%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 3]

Using the adhesive B, the protective film B in the polarizing plate A and the protective film C in the polarizing plate D are aligned in such a way that the absorption axes of the polarizing plates are parallel to each other fit. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film B side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 4]

Using the adhesive B, the protective film C in the polarizing plate B is bonded to the protective film B in the polarizing plate D in such a manner that the absorption axes of the polarizing plates are parallel to each other. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film C side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.8%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. Heat-resistant The polarization degree after the test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 5]

Using the adhesive B, the protective film C in the polarizing plate B and the protective film C in the polarizing plate E are laminated in such a manner that the absorption axes of the polarizing plates are parallel to each other. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film C side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.8%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 6]

Using adhesive B, the protective film C in the polarizing plate B and the protective film C in the polarizing plate D are aligned in such a way that the absorption axes of the polarizing plates are parallel to each other fit. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film B side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 7]

Using the adhesive B, the protective film C in the polarizing plate C and the protective film B in the polarizing plate D are laminated in such a manner that the absorption axes of the polarizing plates are parallel to each other. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film C side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. Heat-resistant The polarization degree after the test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 8]

Using the adhesive B, the protective film C in the polarizing plate C and the protective film C in the polarizing plate E are laminated in such a manner that the absorption axes of the polarizing plates are parallel to each other. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film C side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.8%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 9]

Using the adhesive B, the protective film C in the polarizing plate C and the protective film C in the polarizing plate D are aligned in such a manner that the absorption axes of the polarizing plates are parallel to each other fit. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. The adhesive A is attached to the protective film B side of the polarizing plate D of the composite polarizing plate thus obtained. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 10]

Using the adhesive B, the protective film B in the polarizing plate F is bonded to the protective film B in the polarizing plate D in such a manner that the absorption axes of the polarizing plates are parallel to each other. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film C side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. Heat-resistant The polarization degree after the test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 11]

Using the adhesive B, the protective film B in the polarizing plate F and the protective film C in the polarizing plate E are laminated in such a manner that the absorption axes of the polarizing plates are parallel to each other. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film C side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.8%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 12]

Using adhesive B, stick the protective film B in the polarizing plate F and the protective film C in the polarizing plate D in such a way that the absorption axes of the polarizing plates are parallel to each other Together. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film B side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 13]

Using the adhesive B, the protective film B in the polarizing plate H is bonded to the protective film B in the polarizing plate D in such a manner that the absorption axes of the polarizing plates are parallel to each other. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film C side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizing plate is 99.997%, and the monomer transmission rate is 37.9%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. Heat-resistant The polarization degree after the test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the heat and humidity resistance test was 99.990%.

[Example 14]

Using the adhesive B, the protective film B in the polarizing plate H and the protective film C in the polarizing plate D are laminated in such a manner that the absorption axes of the polarizing plates are parallel to each other. At this time, corona treatment is performed on the surface of the protective film and the surface of the adhesive to be bonded in advance. On the protective film B side of the composite polarizing plate thus obtained, an adhesive A was bonded. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the composite polarizing plate is 99.997%, and the monomer transmission rate is 37.9%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the heat and humidity resistance test was 99.990%.

[Example 15]

Except that the polarizing plate A of Example 1 was changed to the polarizing plate I and the polarizing plate D was changed to the polarizing plate L, a composite polarizing plate was produced in the same manner. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 16]

A composite polarizing plate was produced in the same manner except that the polarizing plate A of Example 2 was changed to the polarizing plate I and the polarizing plate E was changed to the polarizing plate M. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.8%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 17]

A composite polarizing plate was produced in the same manner except that the polarizing plate A of Example 3 was changed to the polarizing plate I and the polarizing plate D was changed to the polarizing plate L. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 18]

A composite polarizing plate was produced in the same manner except that the polarizing plate B of Example 4 was changed to the polarizing plate J and the polarizing plate D was changed to the polarizing plate L. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.8%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 19]

A composite polarizing plate was produced in the same manner except that the polarizing plate B of Example 5 was changed to the polarizing plate J and the polarizing plate E was changed to the polarizing plate M. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.8%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 20]

Except that the polarizing plate B of Example 6 was changed to the polarizing plate J and the polarizing plate D was changed to the polarizing plate L, a composite polarizing plate was produced in the same manner. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 21]

A composite polarizing plate was produced in the same manner except that the polarizing plate C of Example 7 was changed to the polarizing plate K and the polarizing plate D was changed to the polarizing plate L. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 22]

A composite polarizing plate was produced in the same manner except that the polarizing plate C of Example 8 was changed to the polarizing plate K and the polarizing plate E was changed to the polarizing plate M. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.8%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 23]

A composite polarizing plate was produced in the same manner except that the polarizing plate C of Example 9 was changed to the polarizing plate K and the polarizing plate D was changed to the polarizing plate L. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 24]

A composite polarizing plate was produced in the same manner except that the polarizing plate F of Example 10 was changed to the polarizing plate N and the polarizing plate D was changed to the polarizing plate L. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 25]

Except that the polarizing plate F of Example 11 was changed to the polarizing plate N and the polarizing plate E was changed to the polarizing plate M, a composite polarizing plate was produced in the same manner. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.8%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 26]

Except that the polarizing plate F of Example 12 was changed to the polarizing plate N and the polarizing plate D was changed to the polarizing plate L, a composite polarizing plate was produced in the same manner. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

[Example 27]

A composite polarizing plate was produced in the same manner except that the polarizing plate H of Example 13 was changed to the polarizing plate P and the polarizing plate D was changed to the polarizing plate L. The polarization degree of the composite polarizing plate is 99.997%, and the monomer transmission rate is 37.9%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the heat and humidity resistance test was 99.990%.

[Example 28]

A composite polarizing plate was produced in the same manner except that the polarizing plate H of Example 14 was changed to the polarizing plate P and the polarizing plate D was changed to the polarizing plate L. The polarization degree of the composite polarizing plate is 99.997%, and the monomer transmission rate is 37.9%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the heat and humidity resistance test was 99.990%.

[Comparative Example 1]

Adhesive A is attached to the protective film B side of the polarizing plate G. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of polarizing plate G is 99.993%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.94%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 500 hours. The polarization degree after the heat and humidity resistance test was 63.2%.

[Comparative Example 2]

Adhesive A is attached to the protective film B side of the polarizing plate O. When attaching Adhesive A, corona treatment is also performed on the surface of the protective film and the surface of the adhesive in advance. The polarization degree of the polarizing plate O is 99.993%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.94%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 500 hours. The polarization degree after the heat and humidity resistance test was 63.2%.

[Comparative Example 3]

A composite polarizing plate was produced in the same manner except that the polarizing plate A of Example 1 was changed to the polarizing plate Q and the polarizing plate D was changed to the polarizing plate R. The polarization degree of the composite polarizer is 99.998%, and the monomer penetration rate is 38.6%.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Corporation to prepare samples for heat resistance evaluation. The sample thus prepared was put into an oven at 95°C for 1000 hours. The polarization degree after the heat resistance test was 99.996%, but peeling occurred in a region within 1 mm from the end of the polarizing plate.

The produced composite polarizing plate was cut into 40 mm squares and attached to EAGLE XG manufactured by Corning Co., Ltd. to prepare a sample for evaluation of resistance to humidity and heat. The sample thus prepared was put into an oven at 65°C and 95%RH for 1000 hours. The polarization degree after the humidity and heat resistance test was 99.997%.

Table 1 shows the layer configuration of the composite polarizing plate produced in each example. In addition, the results of Examples and Comparative Examples are shown in Table 2.

(Industry availability)

According to the present invention, it is possible to obtain a composite polarizing plate and a liquid crystal panel having excellent durability against heat and humidity.

10‧‧‧Composite polarizer

11A‧‧‧The first polarizing film

11B‧‧‧The second polarizing film

12A‧‧‧The first protective film

12B‧‧‧4th protective film

13, 14‧‧‧ Adhesive layer

15‧‧‧Second protective film

16‧‧‧The third protective film

20‧‧‧Surface treatment layer

Claims (8)

A composite polarizing plate formed by laminating a first polarizing plate and a second polarizing plate, wherein the first polarizing plate is formed by sequentially laminating a first protective film, a first polarizing film with a thickness of 15 μm or less, and a second protective film The second polarizing plate is formed by sequentially stacking a third protective film, a second polarizing film with a thickness of 15 μm or less, and a fourth protective film. The absorption axis of the first polarizing plate is slightly parallel to the absorption axis of the second polarizing plate. On the side of the fourth protective film opposite to the bonding surface of the second polarizing film, there is an adhesive layer for bonding to the liquid crystal cell; the monomer transmittance of the first polarizing plate is less than that of the first 2 The single transmittance of the polarizing plate; the second protective film and the third protective film existing between the first polarizing film and the second polarizing film satisfy the following formulas (1) and (2): Re2 (590)+Re3(590)≦15nm (1) Rth2(590)+Rth3(590)≦20nm (2) However, in the above formulas (1) and (2), Re2(590) and Re3(590) respectively Represents the in-plane retardation value of the second protective film at a wavelength of 590 nm and the in-plane retardation value of a third protective film at a wavelength of 590 nm, and Rth2 (590) and Rth3 (590) represent the second protective film at a wavelength of 590 nm, respectively The phase difference in the thickness direction and the phase difference in the thickness direction of the third protective film at a wavelength of 590 nm. The composite polarizing plate according to item 1 of the patent application scope, wherein the first protective film, the second protective film, and the third protective film each contain a resin selected from the group consisting of cellulose-based resins, polyolefin-based resins, and acrylic-based resins At least one of the formed groups. The composite polarizing plate as described in item 1 or 2 of the patent application scope, wherein at least one of the first protective film, the second protective film, and the third protective film has a moisture permeability of 200 g/m ² Below 24hr. The composite polarizing plate as described in item 1 or 2 of the patent application range, wherein the difference between the thickness of the first polarizing film and the thickness of the second polarizing film is 5 μm or less. The composite polarizing plate according to item 1 or 2 of the patent application, wherein the fourth protective film contains at least one selected from the group consisting of cellulose-based resins, polyolefin-based resins, and acrylic resins. The composite polarizing plate as described in item 1 or 2 of the patent application range, wherein the phase difference of the fourth protective film in the thickness direction at a wavelength of 590 nm is -10 to 10 nm. The composite polarizing plate as described in item 1 or 2 of the patent application, wherein an adhesive is deposited on the surface of the fourth protective film opposite to the surface on which the second polarizing film is deposited. A liquid crystal panel in which a polarizing plate as described in any one of claims 1 to 7 is arranged on at least one side of a liquid crystal cell.

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