KR101646260B1 - Combined polarizing plate and ips mode liquid crystal display device using the same - Google Patents
Combined polarizing plate and ips mode liquid crystal display device using the same Download PDFInfo
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- KR101646260B1 KR101646260B1 KR1020100014986A KR20100014986A KR101646260B1 KR 101646260 B1 KR101646260 B1 KR 101646260B1 KR 1020100014986 A KR1020100014986 A KR 1020100014986A KR 20100014986 A KR20100014986 A KR 20100014986A KR 101646260 B1 KR101646260 B1 KR 101646260B1
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Abstract
The present invention is characterized in that a transparent protective film is laminated on one side of a polarizing film through a first adhesive layer and a first retardation film made of an olefin resin is laminated on the other side of the polarizing film through a second adhesive layer, A second retardation film having a three-layer structure in which a skin layer composed of a (meth) acrylic resin composition containing rubber particles is formed on both sides of a core layer made of a styrenic resin via an adhesive layer on the outer side of the first retardation film, Is provided. The complex polarizing plate is disposed on at least one surface of the IPS mode liquid crystal cell to form an IPS mode liquid crystal display device.
Description
The present invention relates to a composite polarizing plate in which a transparent protective film is bonded to one side of a polarizing film and a retardation film is bonded to the other side, and an IPS mode liquid crystal display device using the same.
BACKGROUND ART [0002] Liquid crystal display devices are used in various display devices because of their low power consumption, low voltage operation, light weight and thinness. The liquid crystal display device is composed of many materials such as a liquid crystal cell, a polarizing film, a phase difference film, a condensing sheet, a diffusion film, a light guide plate, and a light reflection sheet. Therefore, improvements have been actively made aiming at improvement in productivity, lightness, and brightness by reducing the number of constituent films or decreasing the thickness of a film or a sheet.
In addition, a liquid crystal display device is required to have a product that can withstand harsh endurance conditions. For example, in a liquid crystal display device for a car navigation system, the temperature and humidity inside the vehicle on which it is placed may become extremely high. In addition, in displays such as cellular phones and portable terminal devices, and displays for televisions and computers, Depending on the use environment or the installation place thereof, there is a case that the temperature and the humidity change are exposed to a severe condition. Therefore, a product performance capable of enduring the use of such a harsh condition is required.
The polarizing plate usually has a structure in which a transparent protective film is laminated on both sides or one side of a polarizing film made of a polyvinyl alcohol based resin film in which dichroic dye is adsorbed and oriented.
The polarizing film is produced by a method in which a polyvinyl alcohol resin film is subjected to longitudinal uniaxial stretching and dyeing with a dichroic dye, followed by boric acid treatment to cause a crosslinking reaction, followed by washing with water and drying. As the dichroic dye, iodine or dichromatic organic dye is used. A protective film is laminated on both sides or one side of the thus obtained polarizing film to become a polarizing film and is used in a built-in liquid crystal display device. As the protective film, a cellulose acetate based resin film typified by triacetylcellulose is often used, and its thickness is usually about 30 to 120 mu m. In addition, an adhesive composed of an aqueous solution of a polyvinyl alcohol-based resin is often used for lamination of the protective film.
The polarizing plate constituted from such a member may be degraded in polarizing performance or may be liable to peel off from the polarizing film when the polarizing plate is used for a long time under a humid condition.
Therefore, there is an attempt to constitute at least one protective film with a resin other than a cellulose acetate-based resin. For example, in JP-A No. 08-43812-A, it is described that in a polarizing film in which a protective film is laminated on both surfaces of a polarizing film, at least one of the protective films is made of a thermoplastic norbornene resin having a function of a retardation film . JPH09-325216-A discloses that at least one of the protective layers of the polarizing film is composed of a birefringent film.
On the other hand, the styrene-based resin film has been studied as a negative retardation film having a large refractive index in the thickness direction since the polarization ratio of the side chain is larger than the polarization ratio of the main chain of the styrene-based resin in some cases . However, the styrene-based resin film has problems in heat resistance, mechanical strength and chemical resistance, and has not been put to practical use.
Here, the negative retardation film having a large refractive index in the thickness direction means a refractive index n x in the direction of the maximum refractive index (slow axis direction) in the plane and a refractive index in the direction (fast axis direction) when the refractive index of the refractive index of n y, in the thickness direction as n z, n z ≒ n x > n y have the relationship, Nz coefficient defined by (n x -n z) / ( n x -n y) Is approximately 0 (zero).
The heat resistance of a styrenic resin is known to be improved by copolymerizing monomers forming a resin having a high glass transition temperature (hereinafter sometimes abbreviated as Tg), for example, norbornene or maleic anhydride, Mechanical strength and chemical resistance are not sufficient.
A number of techniques have been proposed in which styrene is copolymerized with another monomer or a resin layer is laminated on a styrenic film. For example, JP2002-517583-A discloses that an essentially random copolymer of an aromatic vinyl monomer and an? -Olefin having styrene as a typical example is used as a film, and a multilayer structure of the film and another polymer layer It is also suggested that. JP2003-50316-A and JP2003-207640-A disclose that a terpolymer obtained by copolymerizing an aromatic vinyl monomer having styrene as a typical example with a cyclic olefin monomer and a cyclic olefin monomer is used as a retardation film. JP2003-90912-A discloses that an orientation film made of a norbornene resin and an orientation film made of a styrene-maleic anhydride copolymer resin are laminated through an adhesive layer to form a retardation film. In JP2004-167823-A, Discloses a method for laminating a polystyrene-based sheet on a polyolefin-based multilayer film. JP2006-192637-A discloses that a first layer made of a styrene resin film and a second layer made of an acrylic resin composition in which rubber particles are blended are laminated without passing through an adhesive layer to form a retardation film .
However, in the IPS mode, which is one of the driving modes of the liquid crystal display device, the liquid crystal molecules are oriented substantially parallel to the substrate surface and substantially in the same direction, so that the viewing angle characteristic is superior to the liquid crystal display devices of other driving modes. However, even in the case of various liquid crystal displays in which the viewing angle characteristics including the IPS mode are improved, the viewing angle dependency still occurs.
Various measures have been proposed to compensate the viewing angle dependency of the IPS mode liquid crystal display device. As one of them, a method of compensating the viewing angle of the polarizing plate by the retardation plate is effective. For example, JPH02-160204-A discloses a retardation film having a constant ratio of retardation when it is incident from the vertical direction and retardation when it is incident from the direction of 40 degrees from the normal, for example, As a phase difference film. JPH07-230007-A discloses a retardation film in which thermal shrinkage in a predetermined form is caused to a uniaxially stretched thermoplastic resin film and the angle dependence of retardation is controlled, for example, a retardation film oriented in the thickness direction. Such a retardation film oriented in the thickness direction is sandwiched between two polarizing plates of two polarizing plates sandwiching the liquid crystal cell and the liquid crystal cell substrate between the transmission axis of the adjacent polarizing plate and the slow axis of the retardation plate It is effective to compensate the viewing angle.
Also, see T. In the 'Novel Wide Viewing Angle Polarizer with High Achromaticity', SID 00 DIGEST, p. 1094-1097, Ishinabe et al. Discloses that a phase difference plate having Nz coefficients of 0.25 and 0.8 defined above is more effective. JPH11-133408-A discloses a retardation film (compensation layer) having an optical axis in a direction perpendicular to the substrate surface in a positive uni-axial state between the liquid crystal cell substrate and the polarizing plate for the IPS mode, that is, It is described that a retardation film is disposed.
However, these retardation plates having thickness orientations are inferior in productivity and require precise processing, so that the products are expensive.
Further, regarding the compensation of the viewing angle dependence of the IPS mode liquid crystal display device, the viewing angle dependency is improved by attaching a retardation film (optical compensation sheet) having negative uniaxiality between the liquid crystal cell substrate and at least one polarizing plate, -54982-A. In this publication, an example is shown in which the optical axis of the retarder having negative uniaxial, that is, the fast axis is arranged parallel to the long axis of the liquid crystal molecule. Therefore, it is required to laminate a film for optical compensation as described above on a polarizing plate and supply it as an optical compensation film-integrated polarizing plate. However, in the optical compensation configuration proposed so far, problems such as color shift and color tone inversion are not sufficiently solved, and further optimization is desired.
Further, when two or more retardation films are laminated and used, even if the orientation angle distributions of the individual retardation films are uniform, color unevenness may occur at a specific position when the retardation films are laminated.
An object of the present invention is to provide a composite polarizer having a retardation film which is easy to manufacture and which exhibits excellent viewing angle characteristics when applied to a liquid crystal display device. Another object of the present invention is to provide a composite polarizing plate in which two retardation films are laminated and local color unevenness hardly occurs. It is another object of the present invention to provide a liquid crystal display device having an IPS mode liquid crystal cell and having excellent viewing angle characteristics.
According to the present invention, a transparent protective film is laminated on one side of a polarizing film through a first adhesive layer and a first retardation film made of an olefin resin is laminated on the other side of the polarizing film through a second adhesive layer, A second retardation film having a three-layer structure in which a skin layer made of a (meth) acrylic resin composition containing rubber particles on both sides of a core layer made of a styrenic resin is formed on the outer side of the first retardation film, Is provided.
In the first phase difference film, and the in-plane retardation of 30 to 150 nm, when an in-plane slow axis direction, the in-plane fast axis refractive index of the direction and the thickness direction with n x, n y and n z, respectively, equation: (n x -n z ) / (n x -n y ) is greater than 1 but less than 2, that is, has an index of refraction anisotropy satisfying the following expression (1)
In the second retardation film, it is preferable that the in-plane retardation is 20 to 120 nm and the Nz coefficient defined as described above is less than -2 -0.5, that is, the refractive index anisotropy satisfying the following expression (2).
It is preferable that the change in the angle formed by the orientation angles of the first retardation film and the second retardation film is laminated so as to be between 0.4 and 10 degrees.
The olefin resin constituting the first retardation film is preferably a cycloolefin resin mainly containing a constituent unit derived from an alicyclic olefin.
In the second retardation film, the styrene resin constituting the core layer preferably has a glass transition temperature of 120 캜 or higher, and the glass transition temperature of the (meth) acrylic resin composition constituting the skin layer is preferably 120 캜 or lower.
The first retardation film and the polarizing film made of an olefin resin can be bonded with an aqueous adhesive comprising an aqueous solution of a water-soluble polyvinyl alcohol-based resin, and the aqueous adhesive preferably contains a water-soluble epoxy compound. The first retardation film and the polarizing film may also be bonded with an adhesive comprising an epoxy resin composition containing an epoxy resin which is cured by irradiation of active energy rays or heating. When an epoxy resin composition is used as an adhesive, the epoxy resin preferably has one or more epoxy groups bonded to alicyclic rings in the molecule.
Also, according to the present invention, there is provided an ISP mode liquid crystal display device in which any one of the polarizing plates is disposed on at least one surface of an IPS mode liquid crystal cell. The liquid crystal cell has a transparent protective film on one side of the IPS mode liquid crystal cell and the other side of which has a retardation of in-plane retardation of 10 nm or less and an absolute value of retardation in the thickness direction of 15 nm or less An IPS mode liquid crystal display device in which a polarizing plate is disposed is also provided.
The in-plane retardation Re of the film is a value obtained by multiplying the refractive index difference in the plane by the thickness of the film, and is defined by the following equation (3). The retardation Rth in the thickness direction of the film is a value obtained by multiplying the difference between the average refractive index in the plane and the refractive index in the thickness direction by the thickness of the film, and is defined by the following equation (4). Further, as described in relation to Equations (1) and (2) above, the Nz coefficient is defined by the following equation (5).
(Where n x , n y and n z are the refractive indexes in the film triaxial direction as defined above, and d is the thickness of the film).
The Re, Rth and Nz coefficients can be measured by using various commercially available phase difference systems.
It is common for these values to be measured as a representative value measured at the wavelength near the center of visible light. The retardation value and the Nz coefficient used in this specification are values measured at a wavelength of 590 nm.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing an example of the layer structure of the composite polarizing plate of the present invention. Fig.
Fig. 2 is a distribution diagram of a contrast ratio of a liquid crystal display device manufactured using the composite polarizing plate of Example 1. Fig.
3 is a distribution diagram of a contrast ratio of a liquid crystal display device manufactured using the composite polarizing plate of Example 2. Fig.
4 is a distribution diagram of the contrast ratio of the liquid crystal display device manufactured using the composite polarizing plate of Example 3. Fig.
5 is a distribution diagram of the contrast ratio of the liquid crystal display device manufactured using the composite polarizing plate of Example 4. Fig.
6 is a distribution diagram of the contrast ratio of the liquid crystal display device manufactured using the composite polarizing plate of Comparative Example 1. Fig.
7 is a distribution diagram of the contrast ratio of the liquid crystal display device manufactured using the composite polarizing plate of Example 5. Fig.
8 is a graph plotting the angle formed by the orientation angles of the two retardation films constituting each of the two types of composite polarizers used in Example 5 in the width direction.
[Composite Polarizer]
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing an example of the layer structure of the composite polarizing plate of the present invention. Fig. The composite
The second
[Polarizing Film]
The
As the polyvinyl alcohol-based resin, a saponified polyvinyl acetate-based resin can be used. As the polyvinyl acetate resin, a copolymer of vinyl acetate, which is a homopolymer of vinyl acetate, and other monomers copolymerizable with vinyl acetate, and the like can be given. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.
The saponification degree of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The polymerization degree of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, and preferably about 1,500 to 5,000.
Such a film of the polyvinyl alcohol-based resin is used as a raw film of a polarizing film. The method of forming the polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a known method. The thickness of the polyvinyl alcohol-based original film is not particularly limited, but is, for example, about 10 μm to 150 μm.
The uniaxial stretching of the polyvinyl alcohol based resin film can be performed before, simultaneously with, or after dyeing the dichroic dye. When uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. In addition, uniaxial stretching can be performed in these plural steps.
In the uniaxial stretching, the uniaxial stretching may be performed between the different rolls of the main rolls, or may be uniaxially stretched by using a heat roll. In addition, the uniaxial stretching may be dry stretching in which stretching is performed in the atmosphere, or wet stretching in which a polyvinyl alcohol based resin film is stretched by using a solvent such as water. The stretching magnification is usually about 3 to 8 times.
As a method for dyeing a polyvinyl alcohol-based resin film with a dichroic dye, for example, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye is employed. Specific examples of the dichroic dye include iodine and dichromatic dyes. It is preferable that the polyvinyl alcohol-based resin film is immersed in water before the dyeing treatment.
When iodine is used as the dichroism dye, a method in which a polyvinyl alcohol resin film is dipped in an aqueous solution containing iodine and potassium iodide is generally employed. The content of iodine in this aqueous solution is usually about 0.01 to 1 part by weight per 100 parts by weight of water. The content of potassium iodide is usually about 0.5 to 20 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40 占 폚.
The immersion time (dyeing time) in this aqueous solution is usually about 20 to 1,800 seconds.
On the other hand, when a dichroic dye is used as the dichroic dye, a method of dying and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is generally employed. The content of the dichroic dye in the aqueous solution is generally about 1 × 10 -4 to 10 parts by weight per 100 parts by weight of water and preferably about 1 × 10 -3 to 1 part by weight. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing aid. The temperature of the dichroic dye aqueous solution used for dyeing is usually about 20 to 80 占 폚. The immersion time (dyeing time) in this aqueous solution is usually about 10 to 1,800 seconds.
The boric acid treatment after dyeing with the dichroic dye is usually carried out by immersing the dyed polyvinyl alcohol resin film in an aqueous solution containing boric acid.
The amount of boric acid in the boric acid-containing aqueous solution is usually about 2 to 15 parts by weight and preferably 5 to 12 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye, it is preferable that the aqueous solution containing boric acid contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually about 0.1 to 15 parts by weight, preferably about 5 to 12 parts by weight, per 100 parts by weight of water. The immersion time in the boric acid-containing aqueous solution is usually about 60 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50 占 폚 or higher, preferably 50 to 85 占 폚, and more preferably 60 to 80 占 폚.
The polyvinyl alcohol-based resin film after treatment with boric acid is usually washed with water. The water washing treatment is performed, for example, by immersing the boric acid-treated polyvinyl alcohol resin film in water. The temperature of water in the water washing treatment is usually about 5 to 40 占 폚. The immersion time is usually about 1 to 120 seconds.
After washing with water, drying treatment is carried out to obtain a polarizing film. The drying treatment can be performed using a hot-air dryer or a far-infrared heater. The temperature of the drying treatment is usually about 30 to 100 占 폚, preferably 50 to 80 占 폚. The drying treatment time is usually about 60 to 600 seconds, preferably 120 to 600 seconds.
By the drying treatment, the water content of the polarizing film is reduced to the practical level. The water content thereof is usually 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 is lost, and the polarizing film may be damaged or broken after drying. When the moisture content exceeds 20% by weight, the thermal stability of the polarizing film may be deteriorated.
The thickness of the polarizing film obtained by performing the adsorption orientation of the dichroic dye in this way can usually be about 5 to 40 mu m.
[First retardation film made of olefin resin]
In the complex polarizing plate of the present invention, the
Among them, as the olefin-based resin, a cyclic olefin-based resin, which is a resin mainly containing a constituent unit derived from an alicyclic olefin, is preferably used. Typical examples of the alicyclic olefin constituting the cyclic olefin-based resin include norbornene-based monomers and the like. Norbornene is a compound in which one carbon-carbon bond of a norbornane is a double bond and is named bicyclo [2,2,1] hept-2-ene according to the IUPAC nomenclature. Examples of the substituent of norbornene include 3-substituted, 4-substituted and 4,5-di-substituted with the double bond position of the norbornene at the 1,2-position, and further, dicyclopentadiene Or dimethanonoctahydronaphthalene may also be used as the monomer constituting the cyclic olefin resin.
The cyclic olefin-based resin may or may not have a norbornane ring in its constituent unit. Examples of the norbornene monomer forming the cyclic olefin resin having no norbornane ring in the constituent unit include those which are ring-opened to form a 5-membered ring, typically norbornene, dicyclopentadiene, 1- Or 4-methylnorbornene, 4-phenylnorbornene, and the like. When the cyclic olefin resin is a copolymer, the arrangement of the molecules is not particularly limited, and may be a random copolymer, a block copolymer, or a graft copolymer.
More specific examples of the cyclic olefin resin include, for example, a ring-opening polymer of a norbornene monomer, a ring-opening copolymer of a norbornene monomer and another monomer, a polymer modified product obtained by adding a maleic acid moiety or a cyclopentadiene moiety thereto , Hydrogenated polymers or copolymers thereof, addition polymers of norbornene monomers, addition copolymers of norbornene monomers and other monomers, and the like. As the other monomer in the case of the copolymer,? -Olefins, cycloalkenes, nonconjugated dienes and the like can be given. The cyclic olefin-based resin may also be a copolymer using one or more of norbornene-based monomers and other alicyclic olefins.
Among the above embodiments, a resin obtained by hydrogenating a ring-opening polymer using a norbornene monomer is preferably used as the cyclic olefin resin. Such a cycloolefin resin can be subjected to a stretching treatment to form a retardation film. In addition to the stretching, a shrinkable film having a predetermined shrinkage percentage is bonded to the film and subjected to heat shrinkage treatment, whereby the uniformity is high and a large retardation value May be used as the retardation film.
As commercial products of such a cycloolefin resin using a norbornene monomer, "Zeonex" and "Zeonor" sold by Nippon Zeon Co., Ltd. and "Aton" sold by JSR Co., Ltd. . These cyclic olefin resin films and stretched films thereof are also commercially available. Examples thereof include those sold under the trade names " Zeonor film ", which is commercially available from Nippon Zeon Co., Ltd., and JSR Co., &Quot; ATSON FILM ", and " ESCINA " sold by Sekisui Chemical Co., Ltd.
In the first retardation film used in the present invention, a film made of a mixed resin containing two or more kinds of olefin-based resins, or a film made of a mixed resin of an olefin-based resin and another thermoplastic resin may be used. For example, as the mixed resin containing two or more kinds of olefin resins, a mixture of the cyclic olefin resin and the chain aliphatic olefin resin as described above can be mentioned. When a mixed resin of an olefin resin and another thermoplastic resin is used, the other thermoplastic resin is appropriately selected in accordance with the purpose. Specific examples include polyvinyl chloride resins, cellulose resins, polystyrene resins, acrylonitrile / butadiene / styrene copolymer resins, acrylonitrile / styrene copolymer resins, (meth) acrylic resins, polyvinyl acetate resins, Based resins, polyphenylene sulfide-based resins, polyphenylene sulfide-based resins, polyphenylene sulfide-based resins, polyphenylene sulfide-based resins, polyphenylene sulfide-based resins, polyphenylene sulfide- Based resins, polyetheretherketone-based resins, polyarylate-based resins, liquid crystalline resins, polyamideimide-based resins, polyimide-based resins, and polytetrafluoroethylene-based resins. Each of these thermoplastic resins can be used alone or in combination with at least one other. The thermoplastic resin may be used after any appropriate polymer modification. Examples of the polymer modification include copolymerization, crosslinking, molecular end modification, and stereoregularity impartation.
When a mixed resin of an olefin resin and another thermoplastic resin is used, the content of the other thermoplastic resin is usually about 50% by weight or less and preferably about 40% by weight or less based on the whole resin. By setting the content of other thermoplastic resin within this range, it is possible to obtain a retardation film having a small absolute value of photoelastic coefficient, exhibiting good wavelength dispersion characteristics, and excellent durability, mechanical strength and transparency.
Such an olefin resin can be formed into a film by a casting method from a solution, a melt extrusion method, or the like. When a film is formed from two or more kinds of mixed resins, the film-forming method is not particularly limited. For example, a uniform solution obtained by mixing a resin component at a predetermined ratio with a solvent at the same time, A method of producing a film, a method of melt-mixing a resin component at a predetermined ratio, and a method of producing a film by a melt extrusion method.
The film made of the olefin resin may contain other components such as a residual solvent, a stabilizer, a plasticizer, an anti-aging agent, an antistatic agent, and an ultraviolet absorber, as needed, as long as the object of the present invention is not impaired. Further, a leveling agent may be contained in order to reduce surface roughness.
In the first retardation film made of the olefin based resin film used in the present invention, it is preferable that the in-plane retardation Re is in the range of 30 to 150 nm and the refractive index anisotropy in which the Nz coefficient defined by the formula (5) is more than 1 and less than 2 Do.
The olefin-based resin film having refractive index anisotropy as described above can be obtained by known longitudinal uniaxial stretching, tenter transverse uniaxial stretching, simultaneous biaxial stretching, sequential biaxial stretching, and the like. In order to obtain a desired retardation value, Various temperatures such as a preheating temperature at the time of stretching, a stretching temperature, a heat-set temperature, a cooling temperature and the like and a pattern thereof may be suitably selected.
The stretched cycloolefin resin film used in the present invention preferably has a thickness in the range of 20 to 80 mu m, more preferably in the range of 40 to 80 mu m. When the thickness of the cyclic olefin based resin film is less than 20 占 퐉, handling of the film is difficult and a predetermined retardation value tends to be difficult to develop. On the other hand, when the thickness exceeds 80 占 퐉, The transparency may be lowered or the weight of the obtained polarizing plate may be increased.
[Transparent protective film]
The transparent
Each of these resins may be used alone or in combination with at least one other. These resins can be used after any suitable polymer modification, and examples of such polymer modification include copolymerization, crosslinking, molecular terminal modification, stereoregularity control, reaction between heterogeneous polymers Or a mixture including a case where the above-mentioned reaction is carried out.
Among them, as the material of the transparent protective film, it is preferable to use a (meth) acrylic resin, an ethylene terephthalate resin, a propylene resin, or a cellulose resin as typical examples of the methyl methacrylate resin.
The methyl methacrylate resin is a polymer containing 50% by weight or more of methyl methacrylate units. The content of the methyl methacrylate unit is preferably 70% by weight or more, and may be 100% by weight. The polymer having a methyl methacrylate unit of 100% by weight is a methyl methacrylate homopolymer obtained by polymerizing methyl methacrylate alone.
The methyl methacrylate resin can be obtained by polymerizing a monofunctional monomer mainly comprising methyl methacrylate as a radical polymerization initiator and a chain transfer agent. In the polymerization, a small amount of a polyfunctional monomer may be copolymerized.
Examples of monofunctional monomers copolymerizable with methyl methacrylate include ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethyl methacrylate Methacrylic acid esters other than methyl methacrylate such as hexyl and 2-hydroxyethyl methacrylate; Acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate; Hydroxyalkyl acrylates such as methyl 2- (hydroxymethyl) acrylate, methyl 2- (1-hydroxyethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate and butyl 2- (hydroxymethyl) ; Unsaturated acids such as methacrylic acid and acrylic acid; Halogenated styrenes such as chlorostyrene and bromostyrene; Substituted styrenes such as vinyltoluene and? -Methylstyrene; Unsaturated nitriles such as acrylonitrile and methacrylonitrile; Unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; And unsaturated imides such as phenylmaleimide and cyclohexylmaleimide. Each of these copolymerizable monomers may be used alone or in combination with at least one other copolymerizable monomer.
Examples of polyfunctional monomers copolymerizable with methyl methacrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol Esterified with acrylic acid or methacrylic acid at both terminal hydroxyl groups of ethylene glycol or its oligomer such as di (meth) acrylate, nonaethylene glycol di (meth) acrylate and tetradecaethylene glycol di (meth) acrylate; Esterification of both terminal hydroxyl groups of propylene glycol or its oligomer with acrylic acid or methacrylic acid; (Meth) acrylate, neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate and butanediol di (meth) acrylate esterified with acrylic acid or methacrylic acid; Bisphenol A, an alkylene oxide adduct of bisphenol A, or both terminal hydroxyl groups of these halogen substituents are esterified with acrylic acid or methacrylic acid; Trimethylol propane and pentaerythritol esterified with acrylic acid or methacrylic acid, and epoxy groups of glycidyl acrylate or glycidyl methacrylate added to the terminal hydroxyl groups of these polyhydric alcohols; A dibasic acid such as succinic acid, adipic acid, terephthalic acid, phthalic acid, and halogen substituents thereof, and an alkylene oxide adduct thereof, and the like, in which an epoxy group of glycidyl acrylate or glycidyl methacrylate is ring- Allyl (meth) acrylate; And aromatic divinyl compounds such as divinylbenzene. Among them, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate and neopentyl glycol dimethacrylate are preferably used.
The methyl methacrylate resin may also be one which has undergone a reaction between the copolymerized functional groups. Examples of the reaction include a condensation reaction between a methyl ester group of methyl acrylate and a hydroxyl group of 2- (hydroxymethyl) acrylate in a polymer chain, a condensation reaction between a carboxyl group of acrylic acid and a hydroxyl group of 2- (hydroxymethyl) Polymer chain in-situ dehydration condensation reaction.
Such methyl methacrylate resins are commercially available and can be easily obtained, for example, under the trade names of SUMIFEX (Sumitomo Chemical Co., Ltd.), ACRYPET (manufactured by Mitsubishi Rayon Co., Ltd.) , Delpet (manufactured by Asahi Kasei Kabushiki Kaisha), Parapet (manufactured by Kuraray Co., Ltd.), and Arkurea (manufactured by Nippon Shokubai Co., Ltd.).
The ethylene terephthalate resin means a resin in which at least 80 mol% of the repeating units are composed of ethylene terephthalate, and may contain other dicarboxylic acid component and diol component. Examples of other dicarboxylic acid components include isophthalic acid, 4,4'-dicarboxy diphenyl, 4,4'-dicarboxybenzophenone, bis (4-carboxyphenyl) ethane, adipic acid, , 1,4-dicarboxycyclohexane, and the like.
Examples of other diol components include propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.
These dicarboxylic acid components and diol components may be used in combination of two or more as necessary. In addition, hydroxycarboxylic acids such as p-hydroxybenzoic acid and p-beta-hydroxyethoxybenzoic acid may be used in combination. As other copolymerization component, a dicarboxylic acid component or a diol component containing a small amount of an amide bond, a urethane bond, an ether bond, a carbonate bond or the like may also be used.
As a production method of the ethylene terephthalate resin, terephthalic acid and ethylene glycol (and, if necessary, other dicarboxylic acid or other diol) are directly polycondensed, a method of directly polycondensing a dialkyl ester of terephthalic acid and ethylene glycol (And optionally other diol esters) of terephthalic acid (and other dicarboxylic acids as the case may be) is subjected to a transesterification reaction in the presence of a catalyst (for example, a dialkyl ester of a carboxylic acid or other diol) And a method of polycondensation in the presence of a catalyst. Further, solid-state polymerization may be carried out as needed to improve the molecular weight or reduce the low molecular weight component.
The propylene resin means a polymer obtained by polymerizing a chain olefin monomer in which 80% by weight or more of the repeating units is a propylene monomer with a polymerization catalyst. Of these, propylene homopolymers are preferred. Among the homopolymers of propylene, the component (CXS component) soluble in xylene at 20 占 폚 is more preferably 1% by weight or less, and the CXS component is more preferably 0.5% by weight or less. Also preferred is a copolymer obtained by copolymerizing propylene as a main component and a comonomer copolymerizable therewith at a ratio of 1 to 20% by weight, preferably 3 to 10% by weight.
Propylene copolymer, ethylene, 1-butene, and 1-hexene are preferable as comonomers copolymerizable with propylene. Among them, ethylene is preferably copolymerized in a proportion of 3 to 10% by weight from the viewpoint of comparatively excellent transparency. When the copolymerization ratio of ethylene is 1% by weight or more, transparency is enhanced. On the other hand, if the proportion exceeds 20% by weight, the melting point of the resin is lowered, and the heat resistance required for the protective film may be impaired.
The cellulose-based resin is a resin in which part or all of the hydrogen atoms in the hydroxyl group of the cellulose obtained from the raw cellulose such as cotton linters or wood pulp (hardwood pulp, softwood pulp) and the like are substituted with an acetyl group, a propionyl group and / or a butyryl group, Cellulosic organic acid ester or cellulose mixed organic acid ester. Examples thereof include acetate esters of cellulose, propionic acid esters, butyric acid esters, and mixed esters thereof. Among them, a triacetylcellulose film, a diacetylcellulose film, a cellulose acetate propionate film, a cellulose acetate butyrate film and the like are preferable.
As a method for producing a transparent protective film to be bonded to a polarizing film from such a methyl methacrylate resin, an ethylene terephthalate resin, a propylene resin, a cellulose resin or the like, a method depending on the resin can be suitably selected, But is not limited thereto. For example, there are a solvent casting method in which a resin dissolved in a solvent is poured into a metal band or a drum and the solvent is removed by drying to obtain a film, a resin is heated and kneaded at a temperature not lower than its melting temperature, And a melt extrusion method is used.
In the melt extrusion method, the single layer film can be extruded, and the multilayer film can be extruded simultaneously.
As the film used as the protective film, commercially available products can be easily obtained. In the case of the methyl methacrylate resin film, for example, a trade name of Techoloy (manufactured by Sumitomo Chemical Co., Ltd.) (Available from Mitsubishi Rayon Co., Ltd.), Della Glass (manufactured by Asahi Kasei Kabushiki Kaisha), Para Glass and Como Glass (available from Kabushiki Kaisha Kuraray Co., Ltd.), Arkorea (manufactured by Mitsubishi Rayon Kabushiki Kaisha) Manufactured by Kubai Co., Ltd.).
Examples of the ethylene terephthalate-based resin film include NovaClear (Mitsubishi Chemical Corporation) and Deijin A-PET sheet (manufactured by Dainippon Kasei Kabushiki Kaisha) under trade names.
Examples of the propylene-based resin film include those commercially available under the trade names FILMAX CPP film (manufactured by FILMAX), Suntox (manufactured by Suntox Kabushiki Kaisha), and DOCELLO (Manufactured by Toyo Boseki Kabushiki Kaisha), Dorepai (manufactured by Toray Film Co., Ltd.), Nippon Poly Ace (manufactured by Nippon Polyacetal Co., Ltd.), Daikou FC Ltd.) and the like.
Examples of the cellulose-based resin film include Fuji Tack TD (manufactured by Fuji Film Co., Ltd.) and Nikaaminolta TAC film KC (manufactured by Konica Minolta Opto Kabushiki Kaisha) as trade names.
The transparency protective film used in the present invention can impart anti-scattering property (haze). Examples of a method of imparting antifogging property include a method of mixing inorganic fine particles or organic fine particles into a raw material resin to form a film and a method of forming a film by a multilayer extrusion method in which one side is composed of a resin mixed with fine particles, A method of forming a two-layer film composed of a resin that is not mixed with the resin or a method of forming a three-layer film by using the resin mixed with the particles as an outer layer; a method of coating a coating liquid comprising a mixture of inorganic fine particles or organic fine particles in a curable binder resin And a method of curing the binder resin to provide an antiglare layer is employed.
Examples of the inorganic fine particles for imparting antifogging properties include silica, colloidal silica, alumina, alumina sol, aluminosilicate, alumina-silica composite oxide, kaolin, talc, mica, calcium carbonate, . Examples of the organic fine particles include crosslinked polyacrylic acid particles, methyl methacrylate / styrene copolymer resin particles, crosslinked polystyrene particles, crosslinked polymethyl methacrylate particles, silicone resin particles, polyimide particles and the like .
The haze value of the transparent protective film imparted with antifogging properties is preferably in the range of 6 to 45%. If the haze value of the antifogging protective film is less than 6%, a sufficient antiglare effect may not be exhibited. When the haze value exceeds 45%, the screen of the liquid crystal display device to which the film is applied is faded, and the image quality may be deteriorated.
The haze value can be measured using a commercially available haze meter, for example, a haze / permeability meter HM-150 (manufactured by Sekisui Chemical Co., Ltd., Murakami Co., Ltd.) in accordance with JIS K 7136. In the measurement of the haze value, it is preferable to use a measurement sample in which the film surface is bonded to the glass substrate so that the retardation imparting surface becomes the surface, for example, by using an optically transparent pressure-sensitive adhesive in order to prevent the film from warping.
A functional layer such as a conductive layer, a hard coating layer, and a low reflective layer may be additionally provided on the transparent protective film. When the antiglare layer is formed, a resin composition having these functions may be selected as the coating liquid.
It is preferable that the transparent protective film is subjected to a saponification treatment, a corona treatment, a plasma treatment or the like prior to bonding with the polarizing film.
The thickness of the transparent protective film is usually about 1 to 500 mu m, preferably 10 to 200 mu m, more preferably 20 to 100 mu m in terms of strength and handleability. If the thickness is within this range, the polarizing film is mechanically protected and the polarizing film does not shrink even when exposed under high temperature and high humidity, and stable optical characteristics can be maintained.
[First adhesive layer and second adhesive layer]
As a method for laminating the transparent
The adhesive layer may be appropriately selected depending on the type and purpose of the adherend.
For example, there are a solvent type adhesive, an emulsion type adhesive, a pressure-sensitive adhesive, a moisture-resisting adhesive, a polycondensation adhesive, a solventless adhesive, a film-type adhesive, and a hot-melt type adhesive.
One preferred adhesive forming the second adhesive layer that bonds the polarizing film and the first retardation film is an aqueous adhesive. As the water-based adhesive, for example, a polyvinyl alcohol-based resin may be used as the main component. A commercially available adhesive may be used, or a commercially available adhesive mixed with a solvent or an additive may be used. As a commercially available polyvinyl alcohol-based resin which can be an aqueous adhesive, for example, KL-318 manufactured by Kuraray Co., Ltd. and the like are available.
The water-based adhesive may contain a cross-linking agent. As the crosslinking agent, an amine compound, an aldehyde compound, a methylol compound, an epoxy compound, an isocyanate compound, a polyvalent metal salt and the like are preferable, and an epoxy compound is particularly preferable. Commercially available products of the crosslinking agent include, for example, glyoxal and Sumirez resin 650 (30), which is an aqueous solution of a water-soluble epoxy compound sold by SumikaChem Texex.
As another preferable adhesive, an adhesive composed of an epoxy resin composition containing an epoxy resin which is cured by irradiation with an active energy ray or heating can be given.
When an adhesive composed of such an epoxy resin composition is used, the first retardation film made of the transparent protective film and the olefin resin is bonded to the polarizing film by applying an active energy ray to the applied layer of the adhesive interposed between these films Irradiating or heating the curable epoxy resin to cure the curable epoxy resin contained in the adhesive. The curing of the epoxy resin by irradiation of an active energy ray or by heating is preferably performed by cationic polymerization of an epoxy resin. In this specification, an epoxy resin means a compound having two or more epoxy groups in the molecule.
From the viewpoints of weatherability, refractive index, cationic polymerizability and the like, the epoxy resin contained in the curable epoxy resin composition as an adhesive is preferably an epoxy resin not containing an aromatic ring in the molecule. Examples of such epoxy resins include hydrogenated epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, and the like.
The hydrogenated epoxy resin can be obtained by a method of glycidyl etherifying a nuclear hydrogenated polyhydroxy compound obtained by selectively subjecting a polyhydroxy compound as a raw material of an aromatic epoxy resin to a nucleophilic reaction under pressure in the presence of a catalyst . Examples of the aromatic epoxy resin include bisphenol-type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol S; Novolak type epoxy resins such as phenol novolak epoxy resin, cresol novolak epoxy resin, and hydroxybenzaldehyde phenol novolac epoxy resin; Glycidyl ethers of tetrahydroxyphenylmethane, glycidyl ethers of tetrahydroxybenzophenone, and epoxy polyvinylphenols. The epoxy resin may be used alone or in combination of two or more. Of hydrogenated epoxy resins, hydrogenated glycidyl ethers of bisphenol A are preferred.
The alicyclic epoxy resin means an epoxy resin having at least one epoxy group bonded to the alicyclic ring in the molecule. The "epoxy group bonded to the alicyclic ring" means a bridging oxygen atom -O- in the structure represented by the following formula. In the formula, m is an integer of 2 to 5.
The compound in which one or more hydrogen atoms of the (CH 2 ) m in the above formula are removed from other groups in the chemical structure may be an alicyclic epoxy resin. (CH 2 ) m may be suitably substituted with a straight chain alkyl group such as methyl or ethyl group. Among the alicyclic epoxy resins, epoxy resins having an oxabicyclohexane ring (with m = 3 in the above formula) or an oxabicycloheptane ring (with m = 4 in the above formula) exhibit excellent adhesiveness It is preferable to use it because of betting. Hereinafter, the alicyclic epoxy resin which is preferably used is specifically exemplified, but the present invention is not limited thereto.
(a) epoxycyclohexylmethyl epoxycyclohexanecarboxylates represented by the following formula (I):
(I)
(Wherein R 1 and R 2 represent, independently of each other, a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms).
(b) epoxycyclohexanecarboxylates of alkanediol represented by the following formula (II):
≪
(Wherein R 3 and R 4 represent, independently of each other, a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms, and n represents an integer of 2 to 20).
(c) epoxycyclohexylmethyl esters of dicarboxylic acids represented by the following formula (III):
(III)
(Wherein R 5 and R 6 are each independently a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms, and p represents an integer of 2 to 20).
(d) epoxycyclohexylmethyl ethers of polyethylene glycol represented by the following formula (IV):
(IV)
(Wherein R 7 and R 8 independently represent a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms, and q represents an integer of 2 to 10).
(e) epoxycyclohexyl methyl ethers of alkane diols represented by the following formula (V):
(V)
(Wherein R 9 and R 10 independently represent a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms, and r represents an integer of 2 to 20).
(f) a diepoxy trispyiro compound represented by the following formula (VI):
≪ Formula (VI)
(Wherein R 11 and R 12 independently represent a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms).
(g) a diepoxy monospiro compound represented by the following formula (VII):
(VII)
(Wherein R < 13 > and R < 14 > each independently represent a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms).
(h) vinylcyclohexene epoxides represented by the following formula (VIII):
≪ Formula (VIII)
(Wherein R 15 represents a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms).
(i) epoxycyclopentyl ethers represented by the following formula (IX):
<Formula IX>
(Wherein R < 16 > and R < 17 > each independently represent a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms).
(j) diepoxy tricyclodecane represented by the following formula X:
(X)
(Wherein R 18 represents a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms).
Among the alicyclic epoxy resins exemplified above, the following alicyclic epoxy resins are commercially available, or the like, and are more preferably used because they are relatively easy to obtain.
(A) an esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid with (7-oxa-bicyclo [4.1.0] hept- 1 = R < 2 > = H]
(B) An ester with 4-methyl-7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (4-methyl-7-oxa-bicyclo [4.1.0] hept- Cargo [compound of formula (I) wherein R 1 = 4-CH 3 , R 2 = 4-CH 3 ]
(C) an esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and 1,2-ethanediol [compound of formula (II) wherein R 3 = R 4 = H, n = 2] ,
(D) (7-oxabicyclo [4.1.0] hept-3-yl) methanol and adipic acid [compound of formula (III) wherein R 5 = R 6 = H, p = 4]
(E) (4-methyl-7-oxabicyclo [4.1.0] hept-3-yl) methanol and adipic acid [wherein R 5 = 4-CH 3 , R 6 = 4 -CH 3 , p = 4]
(F) (7- oxabicyclo [4.1.0] hept-3-yl) ether in the cargo Formula V with methanol and 1,2-ethanediol, R 9 = R 10 = a H, r = 2 compound].
Examples of the aliphatic epoxy resin include polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof. More specifically, diglycidyl ether of 1,4-butanediol; Diglycidyl ether of 1,6-hexanediol; Triglycidyl ether of glycerin; Triglycidyl ether of trimethylolpropane; Diglycidyl ether of polyethylene glycol; Diglycidyl ether of propylene glycol; And polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin.
The epoxy resin constituting the adhesive composed of the epoxy resin composition may be used alone, or two or more epoxy resins may be used in combination. The epoxy equivalent of the epoxy resin used in this composition is usually in the range of 30 to 3,000 g / equivalent, preferably 50 to 1,500 g / equivalent. If the epoxy equivalent is less than 30 g / equivalent, the flexibility of the composite polarizer after curing may deteriorate or the adhesive strength may decrease. On the other hand, if it exceeds 3,000 g / equivalent, compatibility with other components contained in the adhesive may be deteriorated.
In this adhesive, cationic polymerization is preferably used as a curing reaction of the epoxy resin in terms of reactivity. To this end, the curable epoxy resin composition which is an adhesive is preferably blended with a cationic polymerization initiator. The cationic polymerization initiator generates a cationic species or a Lewis acid by irradiation or heating of an active energy ray such as visible light, ultraviolet ray, X-ray or electron ray to start polymerization reaction of the epoxy group. Whichever type of cationic polymerization initiator is used, it is preferable from the viewpoint of workability that the potential is imparted. Hereinafter, a cationic polymerization initiator which generates a cationic species or a Lewis acid by irradiation of an active energy ray to initiate a polymerization reaction of an epoxy group is referred to as a " photo cationic polymerization initiator ", and a cationic species or a Lewis acid is generated by heat, Quot; thermal cationic polymerization initiator " is referred to as " thermal cationic polymerization initiator ".
The method of curing the adhesive by irradiation of an active energy ray using a photo cationic polymerization initiator enables curing at room temperature and reduces the need to consider the heat resistance or distortion caused by expansion of the polarizing film, It is advantageous in that the film can be adhered well. Further, since the photo cationic polymerization initiator acts catalytically with light, even when mixed with an epoxy resin, the storage stability and workability are excellent.
The photo cationic polymerization initiator is not particularly limited, and examples thereof include aromatic diazonium salts; Onium salts such as aromatic iodonium salts and aromatic sulfonium salts; Iron-arene complexes and the like.
Examples of the aromatic diazonium salt include benzene diazonium hexafluoroantimonate, benzene diazonium hexafluorophosphate, benzene diazonium hexafluoroborate, and the like. Examples of the aromatic iodonium salt include diphenyl iodonium tetrakis (pentafluorophenyl) borate, diphenyl iodonium hexafluorophosphate, diphenyl iodonium hexafluoroantimonate, di (4-nonylphenyl) iodonium hexafluorophosphate, and the like.
The aromatic sulfonium salts include, for example, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, 4,4'-bis ( Diphenylsulfone bis (hexafluorophosphate), 4,4'-bis [di (? - hydroxyethoxy) phenylsulfonio] diphenylsulfide bis (hexafluoroantimonate) (P-toluyl) sulfonyl] diphenylsulfide bis (hexafluorophosphate), 4,4'-bis [di (? - hydroxyethoxy) phenylsulfonio] (P-toluyl) sulfonium] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4-phenyl Diphenylsulfide hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfone-diphenylsulfide hexafluorophosphate, And the like can be mentioned diphenyl sulfide tetrakis (pentafluorophenyl) borate-antimonate, 4- (p-tert- butylphenyl-carbonyl) -4'-di (p- toluyl) Pony O.
Examples of the iron-arene complexes include xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, xylene-cyclopentadienyl iron ) -Tris (trifluoromethylsulfonyl) methanide, and the like.
Commercial products of these photo cationic polymerization initiators can be easily obtained. For example, "Kayarad PCI-220" and "Kayarad PCI-620" (trade names, manufactured by Nippon Kayaku Co., , "Adeka Optomer SP-150" and "Adeka Optomer SP-170" (manufactured by ADEKA CO., LTD.), "CI-5102" DPI-102 "," DPI-101 "," DPI-102 "," CIP-2070S " DPI-103, DPI-105, MPI-103, MPI-105, BBI-101, BBI-102, BBI-103, BBI- TPS-101, TPS-102, TPS-103, TPS-105, MDS-103, MDS-105, DTS-102 and DTS- PI-2074 " (manufactured by Rhodia), and the like.
Each of these photo cationic polymerization initiators may be used alone or in combination with at least one other. Among them, an aromatic sulfonium salt is preferably used because it has excellent ultraviolet ray absorption property in a wavelength region of 300 nm or more and therefore has excellent curability and can provide a cured product having good mechanical strength and adhesive strength.
The compounding amount of the photo cationic polymerization initiator is usually 0.5 to 20 parts by weight, preferably 1 part by weight or more, more preferably 15 parts by weight or less, based on 100 parts by weight of the epoxy resin.
If the blending amount of the photo cationic polymerization initiator is less than 0.5 part by weight based on 100 parts by weight of the epoxy resin, the curing becomes insufficient and the mechanical strength and the adhesive strength tend to be lowered. If the amount of the photo cationic polymerization initiator is more than 20 parts by weight based on 100 parts by weight of the epoxy resin, the amount of the ionic substance in the cured product increases to increase the hygroscopicity of the cured product, and the durability may be deteriorated.
When a photo cationic polymerization initiator is used, the curable epoxy resin composition as an adhesive may further contain a photosensitizer, if necessary. The use of a photosensitizer improves the reactivity of the cationic polymerization and improves the mechanical strength and adhesive strength of the cured product. Examples of the photosensitizer include a carbonyl compound, an organic sulfur compound, a persulfate, an oxidation-reduction compound, an azo and diazo compound, a halogen compound, a light reducing pigment and the like.
More specific examples of the photosensitizer include benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, and?,? -Dimethoxy-? -Phenylacetophenone; Benzophenone derivatives such as benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis (dimethylamino) benzophenone and 4,4'-bis (diethylamino) benzophenone; Thioxanthone derivatives such as 2-chlorothioxanthone, and 2-isopropylthioxanthone; Anthraquinone derivatives such as 2-chloro anthraquinone and 2-methyl anthraquinone; Acridone derivatives such as N-methyl acridone and N-butyl acridone; Other examples include?,? - diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compound, and halogen compound. Each of these photosensitizers may be used alone or in admixture with at least one other. It is preferable that the photosensitizer is contained in the range of 0.1 to 20 parts by weight in 100 parts by weight of the curable epoxy resin composition.
On the other hand, examples of thermal cationic polymerization initiators include benzylsulfonium salts, thiophenium salts, thioronium salts, benzylammonium, pyridinium salts, hydrazinium salts, carboxylic acid esters, sulfonic acid esters and amine imides. These thermal cationic polymerization initiators can be easily obtained as commercial products, and examples thereof include "ADEKA OPTON CP77" and "ADEKA OPTON CP66" (all manufactured by Adeka Kabushiki Kaisha) and "CI Quot; Sun Aid SI-80L " and " Sun Aid SI-100L " (all manufactured by Nippon Soda Kogyo Co., Ltd.) Manufactured by Kabushiki Kaisha).
The epoxy resin contained in the adhesive may be cured by either a photo cationic polymerization or a thermal cationic polymerization, or may be cured by both photo cationic polymerization and thermal cationic polymerization. In the latter case, a photo cationic polymerization initiator and a thermal cationic polymerization initiator are preferably used in combination.
The curable epoxy resin composition may further contain a compound that promotes cation polymerization such as oxetanes and polyols.
The oxetanes are compounds having a 4-membered ring ether in the molecule, and examples thereof include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl ] Benzene, 3-ethyl-3- (phenoxymethyl) oxetane, di [(3-ethyl-3-oxetanyl) methyl] , Phenol novolak oxetane, and the like. These oxetanes are commercially available as commercially available products, and examples thereof include "AARON oxetane OXT-101", "AARON oxetane OXT-121", "AARON oxetane OXT-211" AARON oxetane OXT-221 " and " AARON oxetan OXT-212 " (all manufactured by Toagosei Co., Ltd.). These oxetanes are contained in the curable epoxy resin composition in an amount of usually 5 to 95% by weight, preferably 30 to 70% by weight.
As the polyol, it is preferable that an acid group other than the phenolic hydroxyl group is not present. For example, a polyol compound having no functional group other than the hydroxyl group, a polyester polyol compound, a polycaprolactone polyol compound, a polyol compound having a phenolic hydroxyl group , Polycarbonate polyol, and the like. The molecular weight of these polyols is usually 48 or more, preferably 62 or more, more preferably 100 or more, further preferably 1,000 or less. These polyols are usually contained in a proportion of not more than 50% by weight, preferably not more than 30% by weight, in the curable epoxy resin composition.
The curable epoxy resin composition may contain other additives such as an ion trap agent, an antioxidant, a chain transfer agent, a sensitizer, a tackifier, a thermoplastic resin, a filler, a flow control agent, A plasticizer, a defoaming agent, and the like. Examples of the ion trap agent include inorganic compounds such as powdery bismuth, antimony, magnesium, aluminum, calcium, titanium and mixtures thereof. Examples of the antioxidant include, for example, And hindered phenol-based antioxidants.
The adhesive made of the curable epoxy resin composition containing the epoxy resin as described above is applied to one or both of the adhered surfaces of the polarizing film and the transparent protective film or to one or both of the adhered surfaces of the polarizing film and the first retardation film Curing adhesive layer is cured by irradiating or heating an active energy ray to form a transparent protective film on the polarizing film and the first retardation film on the polarizing film It can be bonded through an adhesive layer comprising a cured layer of the curable epoxy resin composition. As the coating method of the adhesive, various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater are employed.
The adhesive containing an epoxy resin used for adhering the transparent
As the solvent, it is preferable to use a solvent which dissolves the epoxy resin composition well without lowering the optical performance of the polarizing film. For example, an organic solvent such as hydrocarbons typified by toluene or esters typified by ethyl acetate may be used .
When the adhesive is cured by irradiation of active energy rays, the light source to be used is not particularly limited. For example, a light source such as a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, , A black light lamp, a microwave-excited mercury lamp, and a metal halide lamp. The light irradiation intensity for the curable epoxy resin composition may vary depending on the composition, but it is preferable that the irradiation intensity in the wavelength range effective for activation of the photo cationic polymerization initiator is 0.1 to 100 mW / cm 2 . When the light irradiation intensity of the curable epoxy resin composition is less than 0.1 mW / cm 2, the reaction time becomes long. When the light irradiation intensity exceeds 100 mW / cm 2 , heat radiated from the lamp and heat generated upon polymerization of the curable epoxy resin composition The yellowing of the epoxy resin composition and deterioration of the polarizing film may occur. The light irradiation time for the curable epoxy resin composition is controlled for each composition and is not particularly limited, but is preferably set so that the integrated light quantity expressed as a product of irradiation intensity and irradiation time is 10 to 5,000 mJ / cm 2 Do.
If the integrated light quantity of the curable epoxy resin composition is less than 10 mJ / cm 2 , the generation of active species derived from the photo cationic polymerization initiator is not sufficient and the curing of the adhesive may be insufficient. In addition, if the accumulated light quantity exceeds 5,000 mJ / cm 2 , the irradiation time becomes very long, which may deteriorate the productivity.
When the adhesive is cured by heat, it can be heated by a generally known method. The conditions and the like are not particularly limited, but usually the temperature at which the thermal cationic polymerization initiator compounded in the curable epoxy resin composition generates cationic species or Lewis acid The heating is carried out at a temperature of, for example, about 50 to 200 ° C.
Even when curing is carried out under any of the conditions of irradiation of active energy rays or heating, the transparency and retardation characteristics of the first retardation film made of the polarizing film, the transmittance and the hue, the transparent protective film and the olefin resin, It is preferable to cure in a range not lowered.
[Second retardation film]
The second
The styrene resin constituting the core layer 31 may be a homopolymer of styrene or a derivative thereof, or may be a copolymer of styrene or a derivative thereof and another copolymerizable monomer, or a copolymer of two or more thereof. Examples of the styrene derivative include compounds in which other groups are bonded to styrene such as o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, o-ethylstyrene, Substituted styrenes in which a hydroxyl group, an alkoxy group, a carboxyl group, a halogen or the like is introduced into the benzene nucleus of styrene such as alkylstyrene, hydroxystyrene, tert-butoxystyrene, vinylbenzoic acid, o-chlorostyrene, . Ternary copolymers such as those disclosed in JP2003-50316-A and JP2003-207640-A may also be used. The styrene resin is preferably a copolymer of styrene or a styrene derivative with at least one monomer selected from acrylonitrile, maleic anhydride, methyl methacrylate and butadiene. The styrene-based resin in the core layer is preferably composed of heat-resistant, and generally has a Tg of 100 DEG C or higher. The more preferable Tg of the styrene type resin is 120 DEG C or more.
The thickness of the core layer 31 made of a styrene-based resin is preferably set to be 10 to 100 占 퐉. When the thickness is less than 10 占 퐉, sufficient retardation value may not be easily developed by stretching. On the other hand, when the thickness exceeds 100 μm, the impact strength of the film tends to be weak and the change in retardation due to external stress tends to increase, so that white color tends to occur when applied to a liquid crystal display device And the display performance is liable to be deteriorated.
The
Examples of the (meth) acrylic resin include a homopolymer of an alkyl methacrylate or an alkyl acrylate, a copolymer of an alkyl methacrylate and an alkyl acrylate, and the like. Specific examples of the methacrylic acid alkyl ester include methyl methacrylate, ethyl methacrylate and propyl methacrylate. Specific examples of the acrylic acid alkyl ester include methyl acrylate, ethyl acrylate and propyl acrylate. Commercially available (meth) acrylic resins may be used for such (meth) acrylic resins. Examples of the (meth) acrylic resins include those called impact resistant (meth) acrylic resins, and those referred to as high heat resistant (meth) acrylic resins having a glutaric anhydride structure and a lactone ring structure in the main chain.
The rubber particles to be blended in the (meth) acrylic resin are preferably acrylic ones. The acrylic rubber particles are rubber-elastic particles obtained by polymerizing an acrylic acid alkyl ester such as butyl acrylate or 2-ethylhexyl acrylate as a main component in the presence of a polyfunctional monomer. Such particles having rubber elasticity may be formed as a single layer, or may be a multilayer structure having at least one rubber elastic layer. As the acrylic rubber particles having a multilayer structure, those having rubber elasticity particles as described above as a nucleus and covering the periphery thereof with a hard methacrylic acid alkyl ester polymer, a hard methacrylic acid alkyl ester polymer as a nucleus The periphery of which is covered with an acrylic polymer having rubber elasticity as described above, and that the periphery of the hard core is covered with an acrylic polymer having rubber elasticity, and furthermore, a hard methacrylic acid alkyl ester polymer And the like.
These rubber particles generally have an average diameter of particles formed of an elastic layer in the range of about 50 to 400 nm.
The content of the rubber particles in the (meth) acrylic resin composition constituting the
The thickness of the
As described above, in the second
The
The second
The in-plane retardation is imparted to the
In the
When the
Generally, in a stretched film, an axis whose refractive index is the maximum in a plane is called a slow axis, and since the axis may slightly change at each position in detail, this orientation angle is defined at the same time. The orientation angle can be measured using a commercially available phase difference meter or inspection apparatus, for example, a retardation film / optical material inspection apparatus RETS manufactured by Otsuka Electronics Co., Ltd., as described in the following embodiments. In order to make the change (deviation) of the angle formed by the orientation angles of the
[adhesive]
A
[Liquid crystal display device]
In the composite
The composite polarizing plate may be disposed on both sides of the liquid crystal cell or the composite polarizing plate may be disposed on one side of the liquid crystal cell and another polarizing film may be disposed on the other side of the liquid crystal cell. In the bonding to the liquid crystal cell, the retardation film side is disposed so as to face the liquid crystal cell.
The liquid crystal display device of the present invention may be configured to arrange the complex polarizing plate of the present invention on both sides of the liquid crystal cell or to arrange the complex polarizing plate of the present invention on one side of the liquid crystal cell. In the latter case, a separate polarizing plate may be disposed on the side where the composite polarizing plate of the present invention is not disposed. The liquid crystal display device having such a configuration is particularly effective when the liquid crystal cell is in the transverse electric field mode.
In the liquid crystal display of the present invention, when the complex polarizing plate of the present invention is disposed on one side of the liquid crystal cell, the other side thereof has a retardation in-plane retardation Re of 10 nm or less and an absolute value of retardation Rth in the thickness direction of 15 nm or less It is preferable to dispose a polarizing plate having a protective film on the liquid crystal cell side. The liquid crystal cell side protective film of the polarizing plate is more preferably 5 nm or less in Re and the absolute value of Rth is 10 nm or less.
Examples of the material used for the transparent protective film satisfying the requirement that the in-plane retardation Re is 10 nm or less and the absolute value of the retardation Rth in the thickness direction is 15 nm or less include cellulose resins, cyclic olefin resins, (meth) An acrylic resin, an ethylene terephthalate resin, and a propylene resin.
[Example]
Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the examples, " part (s) " and "% " used in the amounts or contents are by weight unless otherwise specified. Further, the thickness, in-plane and thickness direction retardation, and Nz coefficient of the film were measured by the following methods.
[Measurement method of thickness]
The thickness of the film was measured using Digital Micrometer MH-15M manufactured by Nikon Corporation.
[In-plane retardation, thickness direction retardation and Nz coefficient measurement method]
(KOBRA) -21ADH manufactured by Oji Chemical Co., Ltd., which is based on a parallel Nicol rotation method, was used, and in-plane retardation Re, thickness direction retardation Rth, and thickness direction retardation Nz coefficient was measured.
First, a second retardation film (hereinafter referred to as a " retardation film ") having a three-layer structure in which a skin layer made of a (meth) acrylic resin composition containing rubber particles on both sides of a core layer made of an adhesive, a pressure- Will be described.
[Preparation of aqueous adhesive]
3 parts of a carboxyl group-modified polyvinyl alcohol (KL-318, manufactured by Kuraray Co., Ltd.) was dissolved in 100 parts of water, and a polyamide epoxy additive (Sumikachem Tex Co., (Sumirez resin 650 (30), an aqueous solution having a solid concentration of 30%) was added to prepare an aqueous adhesive.
[Production of adhesive composed of curable epoxy resin composition]
100 parts of bis (3,4-epoxycyclohexylmethyl) adipate, 25 parts of diglycidyl ether of hydrogenated bisphenol A, and 4,4'-bis (diphenylsulfonyl) diphenyl And 2.2 parts of sulphide bis (hexafluorophosphate) were mixed and defoamed to obtain an adhesive composed of a curable epoxy resin composition.
Further, the photo cationic polymerization initiator was formulated as a 50% propylene carbonate solution.
[Production of acrylic pressure-sensitive adhesive]
An organic solvent solution in which a urethane acrylate oligomer and an isocyanate crosslinking agent were mixed with a copolymer of butyl acrylate and acrylic acid was dried by a die coater on a mold releasing surface of a polyethylene terephthalate film (separator) having a thickness of 38 탆 and subjected to releasing treatment To a thickness of 25 μm, and dried to obtain an acrylic pressure-sensitive adhesive.
[Production of a second retardation film having a three-layer structure]
(Retardation film A)
(Manufactured by NOVA Chemical Co., Ltd., "DIRAC (registered trademark) D332", Tg = 131 ° C) as a core layer, about 20% of acrylic rubber particles having an average particle diameter of 200 nm Layer co-extrusion was carried out using a crylic resin ("Technoloy (registered trademark) S001" manufactured by Sumitomo Chemical Co., Ltd., Tg = 105 ° C) as a skin layer to form a skin layer on both surfaces of the core layer Resin 3-layer film was obtained. This three-layer resin film was stretched to produce a retardation film having Re = 47.3 nm and Nz coefficient = -1.06. This is referred to as a retardation film A.
(Retardation film B)
The same three-layer resin film as used in the production of the retardation film A was stretched to prepare a retardation film having Re = 47.3 nm and Nz coefficient = -0.98. This is referred to as a retardation film B.
(Retardation film C)
The same three-layer resin film as used in the production of the above retardation film A was stretched to prepare a retardation film having Re = 55.0 nm and Nz coefficient = -1.1. This is referred to as a retardation film C.
[Example 1]
(A) Fabrication of a composite polarizer
A polyvinyl alcohol film having a thickness of 75 탆 and made of polyvinyl alcohol having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more was uniaxially stretched by about 5 times in a dry state and kept at 60 캜 for one minute And immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.05 / 5/100 for 60 seconds at 28 ° C. and then immersed in an aqueous solution having a potassium iodide / boric acid / water weight ratio of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds Lt; / RTI > Subsequently, the film was washed with pure water at 26 DEG C for 20 seconds, and then dried at 65 DEG C to obtain a polarizing film in which iodine was adsorbed and oriented on polyvinyl alcohol.
On one side of this polarizing film, a triacetyl cellulose film having a thickness of 80 占 퐉, which had been subjected to a saponification treatment, was bonded as a transparent protective film, and on the other side, a first retardation film obtained from Nippon Zeon Co., A retardation film having a Re = 74.2 nm and an Nz coefficient = 1.41 was prepared by bonding a cycloolefin resin having a thickness of 38.6 占 퐉 so that the absorption axis of the polarizing film and the fast axis of the first retardation film were parallel to each other. The bonding was carried out using the water-based adhesive described above, followed by drying at 80 DEG C for 5 minutes to bond the transparent protective film and the first retardation film to the polarizing film. The obtained polarizing plate was then cured at 40 DEG C for 168 hours.
On the first retardation film side of the polarizing plate thus obtained, the retardation film A described above was used as the second retardation film so that the absorption axis of the polarizing film and the fast axis of the second retardation film were parallel to each other To prepare a polarizing plate.
(B) Fabrication and evaluation of a liquid crystal display device
The backlight was removed from a liquid crystal display device (VIERA (model number: TH-37LZ85) manufactured by Panasonic Corporation) containing a liquid crystal cell of the IPS mode and the polarizing plate disposed on the backlight side of the liquid crystal cell Removed, and his glass surface was cleaned. Next, the composite polarizing plate produced in the above (A) was placed on the backlight side of this liquid crystal cell so that its absorption axis was the same as the absorption axis of the polarizing plate on which the absorption axis was originally disposed, And adhered through a pressure-sensitive adhesive to produce a liquid crystal panel. Finally, the liquid crystal display was assembled by disposing the backlight once again.
FIG. 2 shows a distribution chart of the contrast ratio measured with a liquid crystal viewing angle measuring device "EZ contrast 88XL" manufactured by ELDIM, after 30 minutes from the time when the backlight was turned on for this liquid crystal display device. In the figure, the numbers on the horizontal axis represent the polar angle and the numbers on the circumference represent the azimuth angle, respectively, and the distribution of the contrast ratio is represented by black and white shades corresponding to the contrast ratio of the scale shown on the right (FIGS. The same). At a position of an azimuth angle of 135 占 and a polar angle of 60 占 (circled in the figure), a contrast ratio of 192 was shown. Here, the contrast ratio is the ratio of the luminance in the luminance / black display state in the back display state. The azimuth angle is a value obtained by setting the rightward direction of the screen to 0 ° and the counterclockwise direction to plus, and the polar angle is a slope from the normal direction of the screen.
[Example 2]
(A) Fabrication of a composite polarizer
The first retardation film of Example 1 was changed to Re = 79.2 nm and Nz coefficient = 1.21 as a film made of a cyclic olefin resin having a thickness of 29.8 μm obtained from Nippon Zeon Co., The second phase difference film was changed to the above-described retardation film B having a three-layer structure in which a skin layer made of a (meth) acrylic resin composition containing rubber particles was formed on both surfaces of a core layer made of a styrene type resin, To prepare a composite polarizing plate.
(B) Fabrication and evaluation of a liquid crystal display device
A liquid crystal display device was produced in the same manner as in (B) of Example 1, except that the complex polarizing plate thus obtained was used. The distribution of the contrast ratio of the liquid crystal display device measured in the same manner as in Example 1 (B) is shown in Fig. And a contrast ratio of 195 was shown at a position of an azimuth angle of 135 ° and a polar angle of 60 ° (circled in the figure).
[Example 3]
(A) Production of composite polarizer and polarizer
A transparent protective film made of triacetylcellulose was bonded to one side of the polarizing film in the same manner as in Example 2 (A), and on the other side, a film of a cyclic olefin resin having Re = 79.2 nm and Nz coefficient = A first retardation film, and a retardation film B having a three-layer structure in which a skin layer made of a (meth) acrylic resin composition containing rubber particles on both sides of a core layer made of a styrene resin was laminated.
On the other hand, a triacetyl cellulose film having a thickness of 80 占 퐉 and saponified on its surface was bonded to one surface of a polarizing film produced in accordance with the method shown in the first half of Example 1 (A) (KC4UEW, manufactured by Konica Minolta Opto, Inc.) having Re = 0.7 nm and Rth = -0.1 nm was bonded to a transparent protective film made of triacetylcellulose on both sides Thereby producing a polarizing plate. To the bonding, each of the above-described water-based adhesives was bonded and dried at 80 ° C for 5 minutes to adhere the transparent protective films on both sides to the respective polarizing films.
(B) Fabrication and evaluation of a liquid crystal display device
The backlight was detached from the liquid crystal display device including the liquid crystal cell of the same IPS mode as used in (B) of Example 1, the polarizing plate on both surfaces of the liquid crystal cell was removed, and the glass surface thereof was cleaned. Next, the composite polarizing plate shown in the first half of the above (A) is placed on the backlight side of this liquid crystal cell so that the second retardation film is on the liquid crystal cell side and the polarizer shown in the latter half of (A) Of the triacetyl cellulose film was on the side of the liquid crystal cell and the absorption axes of the respective triacetyl cellulose films were the same as the absorption axis of the polarizing plate originally disposed. Finally, the liquid crystal display was assembled by disposing the backlight once again.
The distribution of the contrast ratio measured in this liquid crystal display device in the same manner as in Example 1 (B) is shown in Fig. And a contrast ratio of 195 was shown at a position of an azimuth angle of 135 ° and a polar angle of 60 ° (circled in the figure).
[Example 4]
(A) Production of composite polarizer and polarizer
A transparent protective film made of triacetylcellulose was bonded to one side of the polarizing film in the same manner as in Example 2 (A), and on the other side, a film of a cyclic olefin resin having Re = 79.2 nm and Nz coefficient = A first retardation film, and a retardation film B having a three-layer structure in which a skin layer made of a (meth) acrylic resin composition containing rubber particles on both sides of a core layer made of a styrene resin was laminated.
On the other hand, a triacetyl cellulose film having a thickness of 80 占 퐉 and saponified on its surface was bonded to one surface of a polarizing film produced in accordance with the method shown in the first half of Example 1 (A) A transparent protective film (obtained from Nippon Zeon Co., Ltd.) having Re = 2.1 nm and Rth = 2.8 nm, which was made of a cyclic olefin resin, was bonded and a transparent protective film was laminated on both surfaces. The bonding was carried out by using the water-based adhesive described above, followed by drying at 80 ° C for 5 minutes after bonding, and the transparent protective films on both sides were each adhered to the polarizing film, and then cured at 40 ° C for 168 hours.
(B) Fabrication and evaluation of a liquid crystal display device
The backlight was detached from the liquid crystal display device including the liquid crystal cell of the same IPS mode as used in (B) of Example 1, the polarizing plate on both surfaces of the liquid crystal cell was removed, and the glass surface thereof was cleaned. Next, the composite polarizing plate shown in the first half of the above (A) is placed on the backlight side of this liquid crystal cell so that the second retardation film is on the liquid crystal cell side and the polarizer shown in the latter half of (A) mu m of the cycloolefin resin was placed on the side of the liquid crystal cell and the respective absorption axes were the same as the absorption axis of the polarizing plate originally disposed. Finally, the liquid crystal display was assembled by disposing the backlight once again.
The distribution of the contrast ratio of the liquid crystal display device measured in the same manner as in (B) of Example 1 is shown in Fig. And a contrast ratio of 195 was shown at a position of an azimuth angle of 135 ° and a polar angle of 60 ° (circled in the figure).
[Comparative Example 1]
(A) Production of Polarizing Plate
A triacetyl cellulose film having a thickness of 80 占 퐉 and saponified on its surface was bonded to one side of a polarizing film prepared in accordance with the method shown in the first half of Example 1 (A), and on the other side, A transparent protective film made of triacetyl cellulose having Re = 0.7 nm and Rth = -0.1 nm (KC4UEW, manufactured by Konica Minolta Opto) was bonded, and a transparent protective film made of triacetyl cellulose was laminated on both sides Respectively. To the bonding, each of the above-described water-based adhesives was bonded and dried at 80 ° C for 5 minutes to adhere the transparent protective films on both sides to the respective polarizing films.
(B) Fabrication and evaluation of a liquid crystal display device
A liquid crystal display was manufactured in the same manner as in Example 1 (B) except that the polarizing plate thus prepared was used. The polarizer was bonded to the liquid crystal cell on the side of a triacetyl cellulose film having a thickness of 40 μm. The distribution of the contrast ratio measured in this liquid crystal display device in the same manner as in Example 1 (B) is shown in Fig. And a contrast ratio of 26 was shown at a position of an azimuth angle of 135 占 and a polar angle of 60 占 (circled in the figure).
[Example 5]
(A) Fabrication of a composite polarizer
The first retardation film of Example 1 was changed to Re = 76.2 nm and Nz coefficient = 1.37 as a film made of a cycloolefin resin having a thickness of 35.8 μm obtained from Nippon Zeon Co., The second phase difference film was changed to the above-described retardation film C having a three-layer structure in which a skin layer made of a (meth) acrylic resin composition containing rubber particles was formed on both sides of a core layer made of a styrene resin, In the same manner, a composite polarizing plate was produced.
(B) Fabrication and evaluation of a liquid crystal display device
A liquid crystal display device was produced in the same manner as in (B) of Example 1, except that the complex polarizing plate thus obtained was used. The distribution of the contrast ratio measured in this liquid crystal display device in the same manner as in (B) of Example 1 is shown in Fig. And a contrast ratio of 326 at an azimuth angle of 135 ° and a polar angle of 60 °.
In this liquid crystal display device, local irregular color was seen in the display. Accordingly, the composite polarizing plate used is peeled off from the liquid crystal panel and extracted in the screen width direction centering on the localized color unevenness to obtain a first retardation film made of a three-layer structure and a first retardation film made of a cyclic olefin- And the alignment angles of the corresponding portions in the respective bonded states were measured over a length of 80 cm in the width direction of the screen using a retardation film / optical material inspection apparatus RETS manufactured by OTSUKA ELECTRONICS CO., LTD. (Difference between one alignment angle and the other alignment angle) was calculated. The results are shown in Fig. 8 (a). The change in the angle between the orientation angles of the two retardation films used here was 10 cm at the maximum, which was 0.43 ° at the maximum.
(C) Fabrication and evaluation of other complex polarizing plates and liquid crystal display devices
On the other hand, the same retardation film as that used as the first retardation film in the above (A) was used, and a film of a different lot (35.8 占 퐉 in thickness, Modulus = 1.37] was used as the polymerizable liquid crystal compound, and a composite polarizing plate was produced in the same manner as in (A) except that the liquid crystal display device was assembled in the same manner as in (B) above. The distribution of the contrast ratio of this liquid crystal display device is the same as that in Fig. 7, and the contrast ratio at an azimuth angle of 135 deg. And a polar angle of 60 deg. Is 326,
The composite polarizing plate used here was peeled off from the liquid crystal panel, and the same portion as that of the measurement of the orientation angle from above was extracted in the screen width direction, and the second retardation film and the first retardation film made of the cycloolefin resin were peeled off And the orientation angles of the corresponding portions in the respective bonded states were measured over a length of 80 cm in the width direction of the screen using a retardation film / optical material inspection apparatus RETS manufactured by OTSUKA ELECTRONICS CO., LTD. And the angle formed by the orientation angle (difference between one orientation angle and the other orientation angle) was calculated. The results are shown in Fig. 8 (b). The change in the angle formed by the orientation angles of the two retardation films used here was 10 cm at the maximum, which was 0.27 ° at the maximum.
100: composite polarizer
101: polarizing film
102: transparent protective film
103: first retardation film
104: pressure-sensitive adhesive layer
105: second phase difference film
106: first adhesive layer
107: second adhesive layer
108: Pressure-sensitive adhesive layer
109: Separator
31: core layer
32: Skin layer
Claims (10)
A second retardation film made of a stretched film having a three-layer structure in which a skin layer made of a (meth) acrylic resin composition containing rubber particles on both sides of a core layer made of a styrene-based resin is formed on the outside of the first retardation film via a pressure- A film is stacked,
It said first in phase difference film in-plane retardation of 30 to 150 nm and, when its in-plane slow axis direction, the in-plane fast axis refractive index of the direction and the thickness direction with n x, n y and n z, respectively, equation: (n x -n z ) / (n x -n y ) has an index of refraction anisotropy having an Nz coefficient of more than 1 and less than 2,
Plane retardation in the second retardation film is 20 to 120 nm and the Nz coefficient defined as described above is in the range of more than -2 to less than -0.5,
Wherein a change in the angle formed by the orientation angles of the first retardation film and the second retardation film is laminated so that the change in angle is within a range of 10 cm to 0.4 degrees.
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| JPJP-P-2009-039702 | 2009-02-23 | ||
| JP2009039702 | 2009-02-23 | ||
| JP2009290785A JP5569773B2 (en) | 2009-02-23 | 2009-12-22 | Composite polarizing plate and IPS mode liquid crystal display device using the same |
| JPJP-P-2009-290785 | 2009-12-22 |
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| KR20100096011A KR20100096011A (en) | 2010-09-01 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2012133301A (en) * | 2010-08-11 | 2012-07-12 | Sumitomo Chemical Co Ltd | Liquid crystal display device |
| JP5817141B2 (en) * | 2010-09-30 | 2015-11-18 | 住友化学株式会社 | Liquid crystal display |
| KR101707257B1 (en) * | 2011-08-25 | 2017-02-16 | 주식회사 엘지화학 | Polarizing plate |
| JP2013137521A (en) * | 2011-11-30 | 2013-07-11 | Sumitomo Chemical Co Ltd | Composite retardation plate and composite polarizing plate using the same |
| WO2014148261A1 (en) * | 2013-03-18 | 2014-09-25 | 日本ゼオン株式会社 | Optical laminated body, polarizing plate complex, liquid crystal display device, and production method |
| JP6377322B2 (en) * | 2013-05-30 | 2018-08-22 | 住友化学株式会社 | Optical film laminate and composite polarizing plate using the same |
| JP2015206967A (en) * | 2014-04-23 | 2015-11-19 | 住友化学株式会社 | Method for manufacturing composite polarizing plate |
| JP6550251B2 (en) * | 2015-03-03 | 2019-07-24 | リンテック株式会社 | Adhesive film with optical film |
| JP6550250B2 (en) * | 2015-03-27 | 2019-07-24 | リンテック株式会社 | Adhesive film with optical film |
| KR101892336B1 (en) * | 2015-07-29 | 2018-08-27 | 삼성에스디아이 주식회사 | Polarizing plate |
| KR102534639B1 (en) | 2015-09-30 | 2023-05-18 | 니폰 제온 가부시키가이샤 | liquid crystal display |
| JP6759665B2 (en) * | 2016-03-31 | 2020-09-23 | 住友化学株式会社 | A set of polarizing plates and an IPS mode liquid crystal display device using the same |
| JP6759715B2 (en) * | 2016-05-27 | 2020-09-23 | 住友化学株式会社 | Set of polarizing plate for IPS mode |
| CN110050210A (en) * | 2017-01-30 | 2019-07-23 | 日本瑞翁株式会社 | Display device |
| JP7294094B2 (en) * | 2019-12-02 | 2023-06-20 | コニカミノルタ株式会社 | Optical film and method for producing optical film |
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| JP2006192637A (en) * | 2005-01-12 | 2006-07-27 | Sumitomo Chemical Co Ltd | Resin multilayered film and phase difference film |
| JP2007065452A (en) * | 2005-09-01 | 2007-03-15 | Sumitomo Chemical Co Ltd | Polarizing plate |
| JP2007334295A (en) * | 2006-05-17 | 2007-12-27 | Sumitomo Chemical Co Ltd | Polarizing plate, method for manufacturing the polarizing plate, laminated optical member, and liquid crystal display device |
| JP2008281667A (en) * | 2007-05-09 | 2008-11-20 | Sumitomo Chemical Co Ltd | Method for producing retardation film |
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| JP3118208B2 (en) * | 1996-05-15 | 2000-12-18 | 富士写真フイルム株式会社 | Liquid crystal display |
| TWI370925B (en) * | 2003-11-21 | 2012-08-21 | Zeon Corp | Liquid crystal display apparatus(ii) |
| JP4383903B2 (en) * | 2004-01-23 | 2009-12-16 | 株式会社 日立ディスプレイズ | Polarizing plate and liquid crystal display device using the same |
| JP4548036B2 (en) * | 2004-08-06 | 2010-09-22 | 日本ゼオン株式会社 | Optical laminate, polarizing plate, and liquid crystal display device |
| JP2007316603A (en) * | 2006-04-28 | 2007-12-06 | Sumitomo Chemical Co Ltd | Composite polarizing plate and liquid crystal display device using the same |
| JP2008216998A (en) * | 2007-02-06 | 2008-09-18 | Asahi Kasei Chemicals Corp | Multilayer optical film |
| WO2009004861A1 (en) * | 2007-07-05 | 2009-01-08 | Konica Minolta Opto, Inc. | Liquid crystal display device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006192637A (en) * | 2005-01-12 | 2006-07-27 | Sumitomo Chemical Co Ltd | Resin multilayered film and phase difference film |
| JP2007065452A (en) * | 2005-09-01 | 2007-03-15 | Sumitomo Chemical Co Ltd | Polarizing plate |
| JP2007334295A (en) * | 2006-05-17 | 2007-12-27 | Sumitomo Chemical Co Ltd | Polarizing plate, method for manufacturing the polarizing plate, laminated optical member, and liquid crystal display device |
| JP2008281667A (en) * | 2007-05-09 | 2008-11-20 | Sumitomo Chemical Co Ltd | Method for producing retardation film |
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