KR20100096011A - Combined polarizing plate and ips mode liquid crystal display device using the same - Google Patents

Abstract

PURPOSE: A combined polarizing plate and an IPS mode LCD display device are provided to improve a viewing angle. CONSTITUTION: A transparent protective film(102) is laminated on one surface of a polaroid film(101) through a first bonding agent layer(106). A first phase difference film(103) is made of an olefin-based resin in the different surface of the polaroid film through a second bonding agent layer(107). A skin layer is formed in the outside of the first phase difference film through an adhesive layer(104). The skin layer is made of an acrylic resin compound in both sides of a styrene core layer.

Description

COMPONENT POLARIZING PLATE AND IPS MODE LIQUID CRYSTAL DISPLAY DEVICE USING THE SAME

This invention relates to the composite polarizing plate by which the transparent protective film was bonded to one side of the polarizing film, and the retardation film was bonded to the other side, and the IPS mode liquid crystal display device using the same.

Liquid crystal displays have low power consumption, operate at a low voltage, are used for various display devices utilizing features such as light weight and thinness. A liquid crystal display device is comprised from many materials, such as a liquid crystal cell, a polarizing film, retardation film, a light condensing sheet, a diffusion film, a light guide plate, and a light reflection sheet. Therefore, the improvement aimed at productivity, weight reduction, brightness improvement, etc. is actively performed by reducing the number of constituent films, or making thickness of a film or sheet thin.

In addition, a liquid crystal display device is required for a product that can withstand harsh endurance conditions. For example, in the liquid crystal display device for a car navigation system, the temperature and humidity in the vehicle in which it is placed may become very high, and also in the display of a mobile telephone, a portable terminal device, etc., a display for a television, a computer, etc., Depending on their use environment and installation place, they may be exposed to severe changes in temperature and humidity, so that product performance that can withstand the use of such harsh conditions is required.

The polarizing plate is usually a structure in which a transparent protective film is laminated on both surfaces or one side of a polarizing film made of a polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and oriented.

The polarizing film is manufactured by the method of longitudinally uniaxial stretching and dyeing with a dichroic dye to a polyvinyl alcohol-type resin film, then carrying out a boric acid treatment, causing a crosslinking reaction, and then washing with water and drying. As a dichroic dye, iodine or a dichroic organic dye is used. A protective film is laminated | stacked on both surfaces or one surface of the polarizing film obtained in this way, and it becomes a polarizing film, and is embedded and used for a liquid crystal display device. The cellulose acetate type resin film represented by triacetyl cellulose is used abundantly for a protective film, The thickness is about 30-120 micrometers normally. Moreover, the adhesive agent which consists of aqueous solutions of polyvinyl alcohol-type resin is used for lamination | stacking of a protective film in many cases.

When the polarizing plate comprised from such a member is used for a long time under moist heat conditions, polarization performance may fall, or a protective film and a polarizing film may peel easily.

Therefore, there exists an attempt to comprise at least one protective film from resin other than a cellulose acetate system. For example, JPH08-43812-A describes that in a polarizing film obtained by laminating a protective film on both sides of the polarizing film, at least one of the protective film is composed of a thermoplastic norbornene-based resin having a function of retardation film. . In addition, JPH09-325216-A describes 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 is considered as a negative phase difference film having a larger refractive index in the thickness direction because the polarization rate of the side chain is larger than the polarization rate of the main chain of the styrene resin (may be polarized in the negative portion). . However, the styrene resin film has problems in heat resistance, mechanical strength and chemical resistance, and has not been brought to practical use.

Here, a negative retardation film having a large refractive index in the thickness direction is a direction in which the refractive index of the maximum refractive index direction (ground axis direction) in plane is orthogonal to that in n _x , in-plane (ascending axis direction). The Nz coefficient defined by (n _x -n _z ) / (n _x -n _y ) has a relationship of n _z ≒ n _x > n _y when the refractive index of is n _y and the refractive index of the thickness direction is n _z . Is a film of approximately zero (zero).

The heat resistance of the styrene resin is known to be improved by copolymerizing a monomer forming a resin having a high glass potential temperature (hereinafter sometimes abbreviated as Tg), for example, norbornene and maleic anhydride. Mechanical strength or chemical resistance is not enough.

Many techniques for copolymerizing another monomer in styrene or laminating another resin layer in a styrene film are also proposed. For example, JP2002-517583-A describes the use of an essentially random copolymer of styrene as an example of an aromatic vinyl monomer and an α-olefin as a film, and the multilayer structure of the film with another polymer layer. It is also suggested that. In addition, JP2003-50316-A and JP2003-207640-A disclose that a terpolymer is obtained by copolymerizing a non-cyclic olefin monomer and a cyclic olefin monomer with an aromatic vinyl monomer having styrene as a representative example. In addition, JP2003-90912-A describes laminating an oriented film made of a norbornene-based resin and an oriented film made of a styrene-maleic anhydride copolymer resin through an adhesive layer to form a retardation film, and in JP2004-167823-A, Laminating a polystyrene sheet on a polyolefin multilayer film is described. In addition, JP2006-192637-A describes laminating 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 without using an adhesive layer to form a phase difference film. .

By the way, in the IPS mode which is one of the drive modes of a liquid crystal display device, since a liquid crystal molecule orientates substantially parallel to a board | substrate surface, and in substantially the same direction, it is excellent in viewing angle characteristic compared with the liquid crystal display device of other drive modes. However, even in various liquid crystal display devices 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 for the viewing angle dependence 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, in JPH02-160204-A, a retardation film when it enters from a vertical direction and the retardation when it enters from a 40 degree tilt direction from a normal line is a phase difference film in a fixed range, for example, a thickness direction The retardation film oriented in the direction is described. In addition, JPH07-230007-A describes a phase difference film in which heat shrinkage is performed in a predetermined form on a uniaxially stretched thermoplastic resin film, and the angle dependency of the retardation is controlled, for example, the phase difference film is also oriented in the thickness direction. The transmission axis of the adjacent polarizing plate and the slow axis of the retardation plate are parallel between any one of the polarizing plates and the liquid crystal cell substrate among two polarizing plates arranged such that the retardation plate oriented in the thickness direction with the liquid crystal cell interposed therebetween. It is effective to compensate for the viewing angle.

In addition, T. Ishinabe et al., 'Novel Wide Viewing Angle Polarizer with High Achromaticity', SID 00 DIGEST, p. 1094-1097, describe that a thickness oriented retardation plate having a Nz coefficient of 0.25 and 0.8 defined above is more effective. JPH11-133408-A also has a retardation film (compensation layer) having an optical axis in a direction perpendicular to the substrate plane with positive uniaxiality between the liquid crystal cell substrate and the polarizing plate in the IPS mode, that is, uniaxially oriented in the thickness direction. It is described to arrange one retardation film.

However, since these thickness-oriented retardation plates are bad in productivity and require precise processing, products are expensive.

In addition, as for compensation of the viewing angle dependency of the IPS mode liquid crystal display device, it is improved that the viewing angle dependency is improved by attaching a negative retardation plate (optical compensation sheet) between the liquid crystal cell substrate and at least one polarizing plate. -54982-A. This publication shows an example in which the optical axis of the retardation plate having negative uniaxiality, that is, the fastening axis, is arranged so as to be parallel to the long axis of the liquid crystal molecules. Therefore, it is required to laminate a film for optical compensation as described above on a polarizing plate and to supply it as an optical compensation film integrated polarizing plate. By the way, in the structure of the optical compensation proposed so far, problems, such as a color shift and color tone inversion, have not been fully solved, and further optimization is desired.

Moreover, when two or more retardation films were laminated | stacked and used, even if the orientation angle distribution of each retardation film single-piece | unit is uniform, color unevenness might arise at the specific location when these were laminated | stacked.

An object of the present invention is to provide a composite polarizing plate having a retardation plate that is easy to manufacture and exhibiting excellent viewing angle characteristics when applied to a liquid crystal display device. Still another object of the present invention is to provide a composite polarizing plate in which two phase difference films are laminated and where local color unevenness is unlikely to occur. It is still 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 the polarizing film through the first adhesive layer, and a first retardation film made of olefin resin is laminated on the other side of the polarizing film via the second adhesive layer, Moreover, the 2nd phase difference film which consists of a 3-layered structure in which the skin layer which consists of a (meth) acrylic-type resin composition containing rubber particle on both surfaces of the core layer which consists of styrene resins is formed through the adhesive layer on the outer side of the said 1st phase difference film. This laminated composite polarizing plate is provided.

In the first retardation film, when the in-plane retardation is 30 to 150 nm, and the refractive indices in the in-plane slow axis direction, the in-plane fast axis direction and the thickness direction are set to n _x , n _y and n _z , respectively, the formula: (n _x the Nz coefficient defined by -n _z ) / (n _x -n _y ) is greater than 1 and less than 2, that is, has refractive index anisotropy that satisfies Equation 1 below,

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 greater than -2 and less than -0.5, that is, it has refractive index anisotropy satisfying the following formula (2).

It is preferable to laminate | stack so that the change of the angle which the orientation angle of a 1st retardation film and a 2nd retardation film makes may be 0.4 degrees or less between 10 cm.

It is preferable that the olefin resin which comprises a 1st retardation film is cyclic olefin resin mainly containing the structural unit guide | induced from alicyclic olefin.

In a 2nd phase difference film, it is preferable that the glass transition temperature of the styrene resin which comprises a core layer is 120 degreeC or more, and it is preferable that the glass transition temperature of the (meth) acrylic-type resin composition which comprises a skin layer is 120 degrees C or less.

It is preferable that the 1st phase difference film which consists of olefin resin and a polarizing film can adhere | attach with the aqueous adhesive which consists of aqueous solution of water-soluble polyvinyl alcohol-type resin, It is preferable that this aqueous adhesive contains a water-soluble epoxy compound. Moreover, a 1st retardation film and a polarizing film can also be adhere | attached with the adhesive agent which consists of an epoxy-type resin composition containing the epoxy-type resin hardened | cured by irradiation or heating of an active energy ray. When using an epoxy resin composition as an adhesive agent, it is preferable that this epoxy resin has one or more epoxy groups couple | bonded with an alicyclic ring in a molecule | numerator.

According to the present invention, there is provided an ISP mode liquid crystal display in which any one of the polarizing plates is disposed on at least one side of an IPS mode liquid crystal cell. Moreover, any one of said polarizing plates is arrange | positioned at one side of an IPS mode liquid crystal cell, and the other side has a transparent protective film in a liquid crystal cell side whose in-plane retardation is 10 nm or less, and the absolute value of thickness direction retardation is 15 nm or less. There is also provided an IPS mode liquid crystal display in which a polarizing plate is disposed.

In-plane retardation Re of a film is a value obtained by multiplying the thickness of a film by the in-plane refractive index difference, and is defined by following formula (3). In addition, the thickness direction retardation Rth of a film is a value obtained by multiplying the difference of the in-plane average refractive index and the refractive index of a thickness direction, and thickness of a film, and is defined by following formula (4). In addition, as described with reference to Equations 1 and 2, the Nz coefficient is defined by the following Chemical Formula 5.

(Wherein n _x , n _y and n _z are the refractive indices in the film triaxial direction as defined above, and d is the thickness of the film).

Re, Rth and Nz coefficients can be measured using various retarders commercially available.

It is customary that these values are measured at wavelengths near the center of visible light as typical values, and the retardation value and Nz coefficient as used herein are values measured at a wavelength of 590 nm.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram which shows an example of laminated constitution of the composite polarizing plate of this invention.
FIG. 2 is a distribution diagram of contrast ratios of a liquid crystal display device manufactured using the composite polarizing plate of Example 1. FIG.
3 is a distribution diagram of contrast ratios of the liquid crystal display device produced using the composite polarizing plate of Example 2. FIG.
4 is a distribution diagram of contrast ratios of the liquid crystal display device manufactured using the composite polarizing plate of Example 3. FIG.
5 is a distribution diagram of contrast ratios of a liquid crystal display device manufactured using the composite polarizing plate of Example 4. FIG.
6 is a distribution diagram of contrast ratios of a liquid crystal display device produced using the composite polarizing plate of Comparative Example 1. FIG.
7 is a distribution diagram of contrast ratios of a liquid crystal display device manufactured using the composite polarizing plate of Example 5. FIG.
FIG. 8 is a graph in which the angle formed by the orientation angles of the two phase difference films constituting each of the two kinds of composite polarizing plates used in Example 5 is plotted in the width direction.

[Complex Polarizer]

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram which shows an example of laminated constitution of the composite polarizing plate of this invention. The composite polarizing plate 100 shown in FIG. 1 is a polarizing plate formed by laminating the first phase difference film 103 made of the transparent protective film 102, the polarizing film 101, and the olefinic resin in this order, and the agent of the polarizing plate. The 2nd phase difference film 105 laminated | stacked on the 1st phase difference film 103 via the adhesive layer 104 is provided. The transparent protective film 102 is laminated on one side of the polarizing film 101 via the first adhesive layer 106, and the olefinic resin is formed on the other side of the polarizing film 101 via the second adhesive layer 107. The 1st phase difference film 103 which consists of is laminated | stacked.

The second retardation film 105 has a three-layer structure in which skin layers 32 and 32 made of a (meth) acrylic resin composition containing rubber particles are formed on both surfaces of the core layer 31 made of styrene resin. Have On the surface on the opposite side to the surface bonded to the first retardation film 103 of the second retardation film 105, an adhesive layer 108 for bonding to another member such as a liquid crystal cell is usually provided. A separator 109 is provided for temporarily bonding and protecting the surface of the pressure-sensitive adhesive layer 108 until it is bonded to the member. In addition, although some layers are spaced apart and shown in FIG. 1 for clarity, in practice, adjacent layers are closely bonded. Hereinafter, each member which comprises a composite polarizing plate is demonstrated in detail.

[Polarizing Film]

The polarizing film 101 used for this invention adsorb | sucks a dichroic dye by the process of uniaxially stretching a polyvinyl alcohol-type resin film by a well-known method, and dyeing a polyvinyl alcohol-type resin film with a dichroic dye. It is manufactured through the process, the process of processing the polyvinyl alcohol-type resin film which the dichroic dye adsorb | sucked with boric-acid aqueous solution, and the process of washing with water after the process by boric-acid aqueous solution.

As polyvinyl alcohol-type resin, what saponified polyvinyl acetate type resin can be used. As polyvinyl acetate type resin, the copolymer etc. with other monomer copolymerizable with vinyl acetate besides the polyvinyl acetate which is a homopolymer of vinyl acetate are mentioned. As another monomer copolymerizable with vinyl acetate, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, acrylamide which has an ammonium group, etc. are mentioned, for example.

The saponification degree of polyvinyl alcohol-type resin is about 85-100 mol% normally, and 98 mol% or more is preferable. The polyvinyl alcohol-based resin may be modified. For example, polyvinyl formal, polyvinyl acetal, or the like modified with aldehydes may also be used. Moreover, the polymerization degree of polyvinyl alcohol-type resin is about 1,000-10,000 normally, and about 1,500-5,000 are preferable.

What formed such a polyvinyl alcohol-type resin into a film is used as a raw film of a polarizing film. The method of forming a polyvinyl alcohol-type resin into a film is not specifically limited, It can form into a film by a well-known method. The film thickness of the polyvinyl alcohol-based master film is not particularly limited, but is, for example, about 10 μm to 150 μm.

Uniaxial stretching of a polyvinyl alcohol-type resin film can be performed before, simultaneously with, or after dyeing the dichroic dye. When uniaxial stretching is performed after dyeing, this uniaxial stretching can also be performed before or during boric acid treatment. Moreover, uniaxial stretching can also be performed in these some steps.

In uniaxial stretching, you may extend | stretch uniaxially between rolls from which the circumferential speed differs, and may extend | stretch uniaxially using a thermal roll. In addition, uniaxial stretching may be dry stretching which extends | stretches in air | atmosphere, and it may be wet extending | stretching extending | stretching in the state which swelled the polyvinyl alcohol-type resin film using solvents, such as water. A draw ratio is about 3 to 8 times normally.

As a method of dyeing a polyvinyl alcohol-type resin film with a dichroic dye, the method of immersing a polyvinyl alcohol-type resin film in the aqueous solution containing a dichroic dye is employ | adopted, for example. As a dichroic dye, an iodine or a dichroic dye is used specifically ,. In addition, it is preferable that the polyvinyl alcohol-based resin film is immersed in water before the dyeing treatment.

When using iodine as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing iodine and potassium iodide is employ | adopted normally. 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. In addition, content of potassium iodide is about 0.5-20 weight part normally per 100 weight part of water. The temperature of the aqueous solution used for dyeing is about 20-40 degreeC normally.

In addition, the immersion time (dyeing time) in this aqueous solution is about 20 to 1,800 second normally.

On the other hand, when using a dichroic dye as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing water-soluble dichroic dye is employ | adopted normally. The content of the dichroic dye in this aqueous solution is usually 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 inorganic salts, such as sodium sulfate, as a dyeing adjuvant. The temperature of the dichroic dye aqueous solution used for dyeing is about 20-80 degreeC normally. In addition, the immersion time (dyeing time) in this aqueous solution is about 10 to 1,800 second normally.

Boric acid treatment after dyeing with a dichroic dye is normally performed by immersing the dyed polyvinyl alcohol-type resin film in boric-acid containing aqueous solution.

The amount of boric acid in boric-acid containing aqueous solution is about 2-15 weight part normally per 100 weight part of water, and 5-12 weight part is preferable. When using iodine as a dichroic dye, it is preferable that this boric acid containing aqueous solution contains potassium iodide. The amount of potassium iodide in boric-acid containing aqueous solution is about 0.1-15 weight part normally per 100 weight part of water, and about 5-12 weight part is preferable. Immersion time in boric-acid containing aqueous solution is about 60 to 1,200 second normally, about 150 to 600 second is preferable, and about 200 to 400 second is more preferable. The temperature of the boric acid-containing aqueous solution is usually 50 ° C or higher, preferably 50 to 85 ° C, and more preferably 60 to 80 ° C.

The polyvinyl alcohol-based resin film after boric acid treatment is usually washed with water. The water washing process is performed by immersing the polyvinyl alcohol-type resin film processed by boric acid in water, for example. The temperature of the water in a water washing process is about 5-40 degreeC normally. In addition, immersion time is about 1 to 120 second normally.

After water washing, a drying process is performed and a polarizing film is obtained. A drying process can be performed using a hot air dryer or a far infrared heater. The temperature of a drying process is about 30-100 degreeC normally, and 50-80 degreeC is preferable. The time of a drying process is about 60 to 600 second normally, and 120 to 600 second is preferable.

By the drying treatment, the moisture content of the polarizing film is reduced to the practicality. The moisture content is 5 to 20 weight% normally, and 8 to 15 weight% is preferable. When the moisture content is less than 5% by weight, the flexibility of the polarizing film may disappear, and the polarizing film may be damaged or break after drying. Moreover, when moisture content exceeds 20 weight%, the thermal stability of a polarizing film may fall.

In this way, the thickness of the polarizing film obtained by carrying out the adsorption orientation of a dichroic dye can be made into about 5-40 micrometers normally.

[First Retardation Film Made of Olefin-Based Resin]

In the composite polarizing plate of the present invention, the first retardation film 103 disposed on the liquid crystal cell side is made of an olefin resin. An olefin resin is resin which consists of structural units derived from alicyclic olefins, such as linear aliphatic olefins, such as ethylene and a propylene, or norbornene and its substituent (henceforth these are also called norbornene-type monomers). The olefin resin may be a copolymer using two or more kinds of monomers.

Especially, as olefin resin, cyclic olefin resin which is resin which mainly contains the structural unit guide | induced from alicyclic olefin is used preferably. Norbornene-type monomer etc. are mentioned as a typical example of the alicyclic olefin which comprises cyclic olefin resin. Norbornene is a compound in which one carbon-carbon bond of norbornane is a double bond. According to the IUPAC nomenclature, it is named bicyclo [2,2,1] hept-2-ene. Examples of the substituent of norbornene include 3-substituted, 4-substituted, 4,5-disubstituted, etc., with the double bond position of norbornene at 1,2-position, and further dicyclopentadiene Dimethanooctahydronaphthalene, etc. can also be used as a monomer which comprises cyclic olefin resin.

The cyclic olefin resin may or may not have a norbornane ring in the structural unit. As a norbornene-type monomer which forms cyclic olefin resin which does not have a norbornane ring in a structural unit, it becomes a 5-membered ring by ring opening, for example, norbornene, dicyclopentadiene, 1- Or 4-methylnorbornene, 4-phenylnorbornene and the like. When cyclic olefin resin is a copolymer, the arrangement | positioning state of the molecule is not specifically limited, A random copolymer, a block copolymer, or a graft copolymer may be sufficient.

As a more specific example of cyclic olefin resin, For example, the ring-opening polymer of a norbornene-type monomer, the ring-opening copolymer of a norbornene-type monomer and another monomer, the polymer modified material in which maleic acid addition, cyclopentadiene addition, etc. were made to these, And polymers or copolymers hydrogenated thereto, addition polymers of norbornene-based monomers, addition copolymers of norbornene-based monomers with other monomers, and the like. As another monomer in the case of making a copolymer, (alpha)-olefins, cycloalkenes, nonconjugated dienes, etc. are mentioned. In addition, the cyclic olefin resin may be a copolymer using one kind or two or more kinds of norbornene-based monomers and other alicyclic olefins.

Among the above-mentioned specific examples, as the cyclic olefin resin, a resin hydrogenated to a ring-opening polymer using a norbornene-based monomer is preferably used. Such cyclic olefin resins can be stretched to form a retardation film, and in addition to stretching, a shrinkable film having a predetermined shrinkage ratio is bonded to a heat shrinkage treatment, whereby uniformity is high and a large retardation value can be obtained. It can also be set as the retardation film which has.

As a commercial item of the cyclic olefin resin using such a norbornene-type monomer, "Zonex" and "Zeonor" sold by Nihon Xeon Co., Ltd., "Aton" etc. which are sold from JSR Co., Ltd. are all brand names. There is this. The film of these cyclic olefin resin and its stretched film can also obtain a commercial item, For example, all are sold from "Zeonor film" sold by Nihon Xeon Co., Ltd., JSR Co., Ltd. as a brand name. "Aton Film" and "Esshina" sold by Sekisui Kagaku Kogyo Co., Ltd., etc. are mentioned.

Moreover, the film which consists of a mixed resin containing 2 or more types of olefin resin, and the film which consists of mixed resin of an olefin resin and another thermoplastic resin can also be used for the 1st retardation film used by this invention. For example, as mixed resin containing 2 or more types of olefin resin, the mixture of cyclic olefin resin and chain aliphatic olefin resin as mentioned above is mentioned. When using the mixed resin of an olefin resin and another thermoplastic resin, the other thermoplastic resin is suitably selected suitably according to the objective. 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, and polyvinyl chloride resins. Liden resin, polyamide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polybutylene terephthalate resin, ethylene terephthalate resin, polyphenylene sulfide resin, polysulf And a polyether sulfone resin, a polyether ether ketone resin, a polyarylate resin, a liquid crystalline resin, a polyamideimide resin, a polyimide resin, and a polytetrafluoroethylene resin. Each of these thermoplastic resins can be used alone or in combination with one or more of them. Moreover, the said thermoplastic resin can also be used after carrying out arbitrary appropriate polymer modifications. Examples of the polymer modification include copolymerization, crosslinking, molecular terminal modification, and stereoregularity provision.

When using the mixed resin of an olefin resin and another thermoplastic resin, content of another thermoplastic resin is about 50 weight% or less with respect to the whole resin normally, and about 40 weight% or less is preferable. By carrying out content of another thermoplastic resin in this range, the retardation film which is small in absolute value of a photoelastic coefficient, shows favorable wavelength dispersion characteristic, and is excellent in durability, mechanical strength, and transparency can be obtained.

Such olefin resin can be formed into a film by the casting method from a solution, the melt-extrusion method, etc. When forming a film from 2 or more types of mixed resin, the film forming method is not specifically limited, For example, by the casting method using the uniform solution obtained by stirring-mixing a resin component simultaneously with a solvent at a predetermined ratio. The method of manufacturing a film, the method of melt-mixing a resin component in a predetermined ratio, and the method of manufacturing a film by a melt extrusion method, etc. are employ | adopted.

The film which consists of said olefin resin may contain other components, such as a residual solvent, a stabilizer, a plasticizer, an antioxidant, an antistatic agent, and a ultraviolet absorber, as needed in the range which does not impair the objective of this invention. Moreover, in order to make surface roughness small, you may contain a leveling agent.

1st retardation film which consists of the said olefin resin film used by this invention WHEREIN: It is preferable to have refractive index anisotropy whose in-plane retardation Re is 30-150 nm and Nz coefficient defined by said Formula (5) is more than 1 and less than 2. Do.

The olefin 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, or the like, and the draw ratio and the stretching speed so as to obtain a desired retardation value. What is necessary is just to adjust suitably, and to select various temperatures, such as the preheating temperature at the time of extending | stretching, extending | stretching temperature, heat set temperature, cooling temperature, and its pattern suitably.

It is preferable that the extending | stretching cyclic olefin resin film used for this invention exists in the range of 20-80 micrometers, and it is more preferable to exist in the range of 40-80 micrometers. When the thickness of a cyclic olefin resin film is less than 20 micrometers, handling of a film becomes difficult and it becomes difficult to express a predetermined phase difference value, On the other hand, when the thickness exceeds 80 micrometers, workability becomes inferior, Moreover, transparency may fall or the weight of the obtained polarizing plate may become large.

[Transparent Protective Film]

It is preferable that the transparent protective film 102 laminated | stacked on one side of a polarizing film consists of a material excellent in transparency, mechanical strength, thermal stability, moisture shielding property, stability of retardation value, etc. Although it does not specifically limit as a material which comprises such a transparent protective film, For example, (meth) acrylic-type resin which makes methyl methacrylate type resin a representative example, polyolefin resin which makes propylene resin a typical example, cyclic olefin type Resin, polyvinyl chloride resin, cellulose resin, styrene resin, acrylonitrile butadiene styrene copolymer resin, acrylonitrile styrene copolymer resin, polyvinyl acetate resin, polyvinylidene chloride resin, poly Amide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polysulfone resin, polyether sulfone resin, polyarylate type Resins, polyamideimide resins, polyimide resins, and the like.

Each of these resins can be used alone or in combination with one or more of them. In addition, these resins can also be used after performing any appropriate polymer modification. Examples of the polymer modification include copolymerization, crosslinking, molecular terminal modification, stereoregularity control, and reaction between dissimilar polymers. Modification, such as mixing containing the case of doing, is mentioned.

Among these, as a material of the said transparent protective film, it is preferable to use (meth) acrylic-type resin, ethylene terephthalate-type resin, propylene-type resin, or cellulose-type resin which has methyl methacrylate type resin as a representative example.

Methyl methacrylate type resin is a polymer containing 50 weight% or more of methyl methacrylate units. Content of the methyl methacrylate unit becomes like this. Preferably it is 70 weight% or more, and 100 weight% may be sufficient as it. The polymer in which the methyl methacrylate unit is 100% by weight is a methyl methacrylate homopolymer obtained by polymerizing methyl methacrylate alone.

This methyl methacrylate type resin can be normally obtained by superposing | polymerizing the monofunctional monomer which has methyl methacrylate as a main component in the coexistence of a radical polymerization initiator and a chain transfer agent. In polymerization, a small amount of polyfunctional monomers may be copolymerized.

As a monofunctional monomer copolymerizable with methyl methacrylate, for example, 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 esters such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate; Hydroxyalkyl acrylate esters, such as methyl 2- (hydroxymethyl) acrylate, methyl 2- (1-hydroxyethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, and butyl 2- (hydroxymethyl) acrylate ; Unsaturated acids such as methacrylic acid and acrylic acid; Halogenated styrenes such as chlorostyrene and bromostyrene; Substituted styrenes such as vinyltoluene and α-methylstyrene; Unsaturated nitriles such as acrylonitrile and methacrylonitrile; Unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; Unsaturated imides, such as phenyl maleimide and cyclohexyl maleimide, etc. are mentioned. Each of these copolymerizable monomers may be used alone or in combination with another one or more thereof.

As a polyfunctional monomer copolymerizable with methyl methacrylate, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol Esterification of both terminal hydroxyl groups of ethylene glycol or oligomers thereof such as di (meth) acrylate, nonaethylene glycol di (meth) acrylate and tetradecaethylene glycoldi (meth) acrylate with acrylic acid or methacrylic acid; Esterification of both terminal hydroxyl groups of propylene glycol or an oligomer thereof with acrylic acid or methacrylic acid; Esterified hydroxyl groups of dihydric alcohols such as neopentyl glycol di (meth) acrylate, hexanedioldi (meth) acrylate and butanedioldi (meth) acrylate with acrylic acid or methacrylic acid; Esters of bisphenol A, alkylene oxide adducts of bisphenol A, or both terminal hydroxyl groups of these halogen substituents with acrylic acid or methacrylic acid; Esterification of polyhydric alcohols such as trimethylolpropane and pentaerythritol with acrylic acid or methacrylic acid, and ring-opening addition of an epoxy group of glycidyl acrylate or glycidyl methacrylate to these terminal hydroxyl groups; A ring-opened addition of an epoxy group of glycidyl acrylate or glycidyl methacrylate to dibasic acids such as succinic acid, adipic acid, terephthalic acid, phthalic acid, halogen substituents thereof, and alkylene oxide adducts thereof; Allyl (meth) acrylate; Aromatic divinyl compounds, such as divinylbenzene, etc. are mentioned. Especially, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are used preferably.

The methyl methacrylate resin may be modified by further reacting between the copolymerized functional groups. As the reaction, for example, in the polymer chain demethanol condensation reaction of the methyl ester group of methyl acrylate and the hydroxyl group of methyl 2- (hydroxymethyl) acrylate, the carboxyl group of acrylic acid and the hydroxyl group of 2- (hydroxymethyl) acrylate And dehydration condensation reaction in the polymer chain.

Such a methyl methacrylate type resin can obtain a commercial item easily, for example, Sumpex (made by Sumitomo Chemical Co., Ltd.), acripet (made by Mitsubishi Rayon Corporation) by each brand name, And Delpet (manufactured by Asahi Kasei Kabuki Kaisha), parapet (manufactured by Kabusaki Kaisha Kuraray), and Acryua (manufactured by Nippon Shokubai).

Ethylene terephthalate resin means resin in which 80 mol% or more of a repeating unit consists of ethylene terephthalate, and may contain the other dicarboxylic acid component and diol component. As another dicarboxylic acid component, for example, isophthalic acid, 4,4'-dicarboxydiphenyl, 4,4'-dicarboxybenzophenone, bis (4-carboxyphenyl) ethane, adipic acid, sebacic acid And 1,4-dicarboxycyclohexane may be mentioned.

Examples of other diol components include propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, and ethylene oxide adducts of bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

These dicarboxylic acid components and diol components can also be used in combination of 2 or more type as needed. Moreover, you may use together hydroxycarboxylic acids, such as p-hydroxy benzoic acid and p- (beta) -hydroxyethoxy benzoic acid. Moreover, as another copolymerization component, the dicarboxylic acid component or diol component containing a small amount of an amide bond, a urethane bond, an ether bond, a carbonate bond, etc. may be used.

As a method for producing an ethylene terephthalate-based resin, a method of directly polycondensing terephthalic acid and ethylene glycol (and other dicarboxylic acids or other diols as necessary), dialkyl esters and ethylene glycol of terephthalic acid (and other dicaca as necessary) A method of polycondensation after the transalkylation of a dialkyl ester or another diol of a carboxylic acid, an ethylene glycol ester of terephthalic acid (and other dicarboxylic acid if necessary) and a diol ester of The method of polycondensation in presence is employ | adopted. If necessary, the solid phase polymerization may be carried out to improve the molecular weight or to reduce the low molecular weight component.

A propylene resin means what superposed | polymerized the linear olefin monomer whose 80 weight% or more of a repeating unit is a propylene monomer using the catalyst for superposition | polymerization. Especially, it is preferable that it is a homopolymer of propylene. In the homopolymer of propylene, it is more preferable that the component (CXS component) soluble in 20 degreeC xylene is 1 weight% or less, and it is still more preferable that CXS component is 0.5 weight% or less. Moreover, the copolymer which copolymerized mainly the propylene and the comonomer copolymerizable with it in 1 to 20 weight% ratio, Preferably it is 3 to 10 weight% ratio is also preferable.

When using a propylene copolymer, as comonomer copolymerizable with propylene, ethylene, 1-butene, and 1-hexene are preferable. Especially, it is preferable to copolymerize ethylene in the ratio of 3 to 10 weight% from the point which is comparatively excellent in transparency. By making the copolymerization ratio of ethylene into 1 weight% or more, the effect which raises transparency appears. On the other hand, when the ratio exceeds 20 weight%, melting | fusing point of resin will become low and the heat resistance requested | required of a protective film may be impaired.

Cellulose-based resin is a part or all of the hydrogen atoms in the hydroxyl group of the cellulose obtained from the raw material cellulose, such as cotton linter and wood pulp (softwood pulp, conifer pulp) is substituted with an acetyl group, propionyl group and / or butyryl group, It means a cellulose organic acid ester or a cellulose mixed organic acid ester. For example, what consists of an acetate ester of cellulose, a propionic acid ester, butyric acid ester, these mixed ester, etc. are mentioned. Especially, a triacetyl cellulose film, a diacetyl cellulose film, a cellulose acetate propionate film, a cellulose acetate butyrate film, etc. are preferable.

What is necessary is just to select suitably the method according to the resin as a method of manufacturing the transparent protective film which adheres to a polarizing film from such methyl methacrylate type resin, ethylene terephthalate type resin, a propylene resin, a cellulose resin, etc., It is not limited. For example, a solvent casting method in which a resin dissolved in a solvent is cast in a metal band or drum, and the solvent is dried to remove the film to obtain a film, and the resin is heated and kneaded above its melting temperature to extrude from a die to cool the film. The resulting melt extrusion method is employed.

In the melt extrusion method, it is also possible to extrude a single layer film and to coextrude a multilayer film.

The film used as a protective film can obtain a commercial item easily, and if it is a methyl methacrylate-type resin film, it will be a brand name, respectively, and a technoloid (manufactured by Sumitomo Chemical Co., Ltd.) and an acrylite, respectively. And acrylic flan (above, manufactured by Mitsubishi Rayon Kabuki Kaisha), dela glass (made by Asahi Kasei Kabuki Kaisha Co., Ltd.), paraglass and como glass (above Kabushiki Kaisha Kuraray Co., Ltd.), Acryua (Kabushiki Kaisha Nippon Show) Cubai manufacture) etc. are mentioned.

Examples of the ethylene terephthalate resin film include Nova Clear (manufactured by Mitsubishi Chemical Co., Ltd.) and Teijin A-PET sheet (manufactured by Teijin Kasei Co., Ltd.).

As the propylene resin film, for example, FILMAX CPP film (manufactured by FILMAX, Inc.), Suntox (manufactured by Suntox Corp.), Docelo (Docello Corp.) Kaisha Co., Ltd., Toy Pyro Film (Toyo Bonde Co., Ltd.), Torepan (Toray Film Co., Ltd. Co., Ltd.), Nippon Polyace (Nihon Polyace Co., Ltd.), Daiko FC Tamura Kagaku Co., Ltd. make) etc. are mentioned.

Moreover, as a cellulose resin film, FujiTac TD (made by Fujifilm Co., Ltd.), Nika Minolta TAC film KC (made by Konica Minolta Opto Co., Ltd.) etc. are mentioned, for example in a brand name.

Anti-glare (haze) can be provided to the transparent protective film used for this invention. As a method of imparting anti-glare property, for example, a method of mixing inorganic fine particles or organic fine particles into a raw material resin to form a film, and multilayer extrusion, one of them is composed of a resin in which fine particles are mixed, and the other is fine particles. A method of making a two-layer film composed of unmixed resin, or a method of making a three-layer film with the resin mixed with particles outward, and a coating liquid obtained by mixing inorganic fine particles or organic fine particles with one side of the film to the curable binder resin. Is coated, and the binder resin is cured to provide an antiglare layer.

Examples of the inorganic fine particles for imparting anti-glare properties include silica, colloidal silica, alumina, alumina sol, aluminosilicate, alumina-silica composite oxide, kaolin, talc, mica, calcium carbonate, calcium phosphate, and the like. Can be. In addition, 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. .

It is preferable that the haze value of the transparent protective film provided with anti-glare property exists in 6 to 45% of range. When the haze value of an anti-glare protective film is less than 6%, sufficient anti-glare effect may not appear. Moreover, when the haze value exceeds 45%, the screen of the liquid crystal display device to which this film is applied may fade, and a fall of image quality may be caused.

The haze value can be measured in accordance with JIS K 7136 using a commercially available haze meter, for example, a haze permeability meter HM-150 (manufactured by Murakami Shikisai Kijutsu Genjujo Co., Ltd.). In the measurement of a haze value, in order to prevent curvature of a film, it is preferable to use the measurement sample which bonded the film surface to the glass substrate so that anti-glare surface may become surface using an optically transparent adhesive, for example.

On said transparent protective film, functional layers, such as a conductive layer, a hard coat layer, and a low reflection layer, can be further provided. When forming the said anti-glare layer, you may select the resin composition which has these functions as the coating liquid.

In addition, it is preferable to perform a saponification process, a corona treatment, a plasma process, etc. before a transparent protective film is bonded to a polarizing film.

The thickness of a transparent protective film is about 1-500 micrometers normally from a viewpoint of strength, handleability, etc., 10-200 micrometers is preferable, and its 20-100 micrometers are more preferable. 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 properties can be maintained.

[First adhesive layer and second adhesive layer]

As a method of laminating | stacking the 1st phase difference film 103 which consists of a transparent protective film 102 and olefin resin on the polarizing film 101, the 1st and 2nd adhesive bond layers 106 and 107 are provided, respectively, A method of integrating is employed. At this time, 0.1-35 micrometers is preferable and, as for the thickness of an adhesive bond layer, 0.1-15 micrometers is more preferable. If it is this range, lifting or peeling will not arise between the 1st phase difference film which consists of a transparent protective film and olefin resin laminated | stacked, and a polarizing film, and the adhesive force which is practically no problem is obtained.

An adhesive bond layer is suitable according to the kind and objective of a to-be-adhered body, and can use a suitable thing.

Examples thereof include solvent adhesives, emulsion adhesives, pressure sensitive adhesives, rehumidifying adhesives, polycondensation adhesives, solvent-free adhesives, film adhesives, and hot melt adhesives.

One preferred adhesive for forming the second adhesive layer for bonding the polarizing film and the first retardation film is an aqueous adhesive. As this aqueous adhesive agent, for example, polyvinyl alcohol-based resin may be the main component. A commercially available thing may be used for an aqueous adhesive, and what mixed the solvent and the additive with the commercially available adhesive agent can also be used. As a commercially available polyvinyl alcohol-type resin which can become an aqueous adhesive agent, KL-318 by Kuraray Co., Ltd., etc. are mentioned, for example.

This aqueous adhesive may contain a crosslinking agent. As a crosslinking agent, an amine compound, an aldehyde compound, a methylol compound, an epoxy compound, an isocyanate compound, a polyvalent metal salt, etc. are preferable, and an epoxy compound is especially preferable. Commercially available products of the crosslinking agent include glyoxal and Sumirez resin 650 (30), which is an aqueous solution of a water-soluble epoxy compound sold by Sumika Chemtex Co., Ltd.

Moreover, as another preferable adhesive agent, the adhesive agent which consists of an epoxy resin composition containing the epoxy resin which hardens | cures by irradiation or heating of an active energy ray is mentioned.

When using the adhesive agent which consists of such an epoxy resin composition, adhesion | attachment with the 1st phase difference film which consists of a transparent protective film and an olefin resin, and a polarizing film is an active energy ray with respect to the application layer of the adhesive agent interposed between these films. It can carry out by irradiating or hardening and hardening curable epoxy resin contained in an adhesive agent. Curing of the epoxy resin by irradiation or heating of an active energy ray is preferably performed by cationic polymerization of the epoxy resin. In addition, in this specification, an epoxy resin means the compound which has two or more epoxy groups in a molecule | numerator.

In view of weather resistance, refractive index, cationic polymerizability, and the like, the epoxy resin contained in the curable epoxy resin composition as the adhesive is preferably an epoxy resin containing no aromatic ring in the molecule. As such an epoxy resin, a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, etc. can be illustrated.

The hydrogenated epoxy resin can be obtained by a method of glycidyl etherifying a hydrogenated polyhydroxy compound obtained by selectively nucleating a polyhydroxy compound which is a raw material of an aromatic epoxy resin under pressure in the presence of a catalyst. . As an aromatic epoxy resin, For example, Bisphenol-type epoxy resins, such as the diglycidyl ether of bisphenol A, the diglycidyl ether of bisphenol F, and the diglycidyl ether of bisphenol S; Novolak-type epoxy resins, such as a phenol novolak epoxy resin, a cresol novolak epoxy resin, and a hydroxy benzaldehyde phenol novolak epoxy resin; Polyfunctional epoxy resins, such as glycidyl ether of tetrahydroxy phenylmethane, glycidyl ether of tetrahydroxy benzophenone, and epoxidized polyvinyl phenol, etc. are mentioned. Among the hydrogenated epoxy resins, glycidyl ethers of hydrogenated bisphenol A are preferable.

An alicyclic epoxy resin means the epoxy resin which has one or more epoxy groups couple | bonded with an alicyclic ring in a molecule | numerator. "The epoxy group couple | bonded with an alicyclic ring" means the oxygen atom -O- of bridge | crosslinking in the structure shown by following formula. In the following formula, m is an integer of 2-5.

The compound bonded to (CH _{2) m} 1 form one or other chemical group of the structure removed, a plurality of hydrogen atoms in the above formula may be a cycloaliphatic epoxy resin. One or a plurality of hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. Among the alicyclic epoxy resins, epoxy resins having an oxabicyclohexane ring (m = 3 in the above formula) or an oxabicycloheptan ring (m = 4 in the above formula) exhibit excellent adhesion. It is used preferably because it is a bet. Although the alicyclic epoxy resin used preferably below is concretely illustrated, it is not limited to these compounds.

(a) Epoxycyclohexylmethylepoxycyclohexanecarboxylates represented by the following formula (I):

<Formula I>

(Wherein R ¹ and R ² each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

(b) epoxycyclohexanecarboxylates of alkanediols represented by the following formula (II):

<Formula II>

(Wherein R ³ and R ⁴ independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and n represents an integer of 2 to 20).

(c) epoxycyclohexyl methyl esters of dicarboxylic acids represented by the following formula (III):

<Formula III>

(Wherein R ⁵ and R ⁶ independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and p represents an integer of 2 to 20).

(d) epoxycyclohexyl methyl ethers of polyethylene glycol represented by the following general formula (IV):

<Formula IV>

(Wherein R ⁷ and R ⁸ independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and q represents an integer of 2 to 10).

(e) Epoxycyclohexylmethyl ethers of alkanediols represented by the following formula (V):

(V)

(Wherein R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and r represents an integer of 2 to 20).

(f) a diepoxy citrisspiro compound represented by the following formula (VI):

<Formula VI>

(Wherein R ¹¹ and R ¹² independently of each other represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

(g) a diepoxymonospiro compound represented by the following formula (VII):

<Formula VII>

(Wherein R ¹³ and R ¹⁴ independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

(h) vinylcyclohexenediepoxides represented by the following formula (VIII):

<Formula VIII>

(In formula, R <^15> represents a hydrogen atom or a C1-C5 linear alkyl group.).

(i) epoxycyclopentyl ethers represented by the following general formula (IX):

<Formula IX>

(Wherein R ¹⁶ and R ¹⁷ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

(j) diepoxytricyclodecanes represented by the following general formula (X):

<Formula X>

(Wherein R ¹⁸ represents a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

Among the alicyclic epoxy resins exemplified above, the following alicyclic epoxy resins are commercially available, or are used as analogues thereof for reasons such as relatively easy to obtain.

(A) esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid with (7-oxa-bicyclo [4.1.0] hept-3-yl) methanol [R in formula I, ¹ = R ² = H];

(B) ester of 4-methyl-7-oxabicyclo [4.1.0] heptan-3-carboxylic acid with (4-methyl-7-oxa-bicyclo [4.1.0] hept-3-yl) methanol Cargo [compound of formula I, R ¹ = 4-CH ₃ , R ² = 4-CH ₃ ],

(C) esterified product of 7-oxabicyclo [4.1.0] heptan-3-carboxylic acid with 1,2-ethanediol [compound of R ³ = R ⁴ = H, n = 2 in Formula II] ,

(D) an esterified product of (7-oxabicyclo [4.1.0] hept-3-yl) methanol with adipic acid [in formula III, R ⁵ = R ⁶ = H, p = 4;

(E) an esterified product of (4-methyl-7-oxabicyclo [4.1.0] hept-3-yl) methanol with adipic acid [in Formula III, R ⁵ = 4-CH ₃ , R ⁶ = 4 -CH ₃ , a compound of p = 4],

(F) etherified product of (7-oxabicyclo [4.1.0] hept-3-yl) methanol with 1,2-ethanediol [wherein R ⁹ = R ¹⁰ = H, r = 2 compound].

Moreover, as an aliphatic epoxy resin, the polyglycidyl ether of an aliphatic polyhydric alcohol or its alkylene oxide adduct is mentioned. 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; The polyglycidyl ether of the polyether polyol obtained by adding 1 type, or 2 or more types of alkylene oxide (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohols, such as ethylene glycol, propylene glycol, and glycerin, is mentioned.

The epoxy resin which comprises the adhesive agent which consists of an epoxy resin composition may be used individually by 1 type, and may use 2 or more types together. The epoxy equivalent of the epoxy resin used for this composition is 30-3,000 g / equivalent normally, Preferably it exists in the range of 50-1,500 g / equivalent. When epoxy equivalent is less than 30 g / equivalent, the flexibility of the composite polarizing plate after hardening may fall, or adhesive strength may fall. On the other hand, when it exceeds 3,000 g / equivalent, compatibility with the other component contained in an adhesive may fall.

In this adhesive agent, cationic polymerization is preferably used as the curing reaction of the epoxy resin in terms of reactivity. For that purpose, it is preferable that the curable epoxy resin composition which is an adhesive mix | blends a cationic polymerization initiator. The cationic polymerization initiator generates cationic species or Lewis acids by irradiation or heating of active energy rays such as visible rays, ultraviolet rays, X-rays, electron beams, and initiates a polymerization reaction of an epoxy group. In any type of cationic polymerization initiator, it is preferable from the viewpoint of workability that potential is imparted. Hereinafter, the cationic species which generate | occur | produces cationic species or Lewis acid by irradiation of an active energy ray, and starts the polymerization reaction of an epoxy group is called "photocationic polymerization initiator", The cationic species or Lewis acid is generated by heat, and the polymerization reaction of an epoxy group is carried out. The cationic polymerization initiator which starts the process is called "thermal cationic polymerization initiator."

In the method of curing the adhesive by irradiation of active energy rays using the photocationic polymerization initiator, curing at room temperature becomes possible, and the need to consider the heat resistance or distortion due to expansion of the polarizing film is reduced, and the transparent protective film and the polarization are It is advantageous in that a film can be adhere | attached well. Moreover, since a photocationic polymerization initiator acts catalytically with light, even if it mixes with an epoxy resin, it is excellent in storage stability and workability.

Although it does not specifically limit as a photocationic polymerization initiator, For example, Aromatic diazonium salt; Onium salts such as aromatic iodonium salts and aromatic sulfonium salts; Iron-arene complexes; and the like.

As aromatic diazonium salt, benzenediazonium hexafluoro antimonate, benzenediazonium hexafluoro phosphate, benzenediazonium hexafluoro borate etc. are mentioned, for example. As the aromatic iodonium salt, for example, diphenyl iodonium tetrakis (pentafluorophenyl) borate, diphenyl iodonium hexafluorophosphate, diphenyl iodonium hexafluoro antimonate, di (4-nonylphenyl) iodonium hexafluorophosphate etc. are mentioned.

Examples of the aromatic sulfonium salts include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, and 4,4'-bis ( Diphenylsulfonio) diphenylsulphibis (hexafluorophosphate), 4,4'-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulphibis (hexafluoroantimo Nate), 4,4'-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulphibis (hexafluorophosphate), 7- [di (p-toluyl) sulfonio] 2-isopropyl thioxanthone hexafluoroantimonate, 7- [di (p-toluyl) sulfonio] -2-isopropyl thioxanthone tetrakis (pentafluorophenyl) borate, 4-phenyl Carbonyl-4'-diphenylsulfonio-diphenylsulphidehexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfonio-diphenylsulphidehexafluoro And the like can be mentioned diphenyl sulfide tetrakis (pentafluorophenyl) borate-antimonate, 4- (p-tert- butylphenyl-carbonyl) -4'-di (p- toluyl) Pony O.

Moreover, as an iron-arene complex, xylene cyclopentadienyl iron (II) hexafluoro antimonate, cumene cyclopentadienyl iron (II) hexafluoro phosphate, xylene cyclopentadienyl iron (II), for example ) -Tris (trifluoromethylsulfonyl) methane etc. are mentioned.

Commercially available products of these photo cationic polymerization initiators can be easily obtained, and for example, "Kayarad PCI-220" and "Kayarad PCI-620" (trade name, manufactured by Nippon Kayaku Co., Ltd.) under the trade names, respectively. , "UVI-6990" (Union Carbide Co., Ltd.), "Adeka Optomer SP-150" and "Adeka Optomer SP-170" (above, made by Adeka Co., Ltd.), "CI-5102", " "CIT-1370", "CIT-1682", "CIP-1866S", "CIP-2048S" and "CIP-2064S" (above, Nippon Soda Co., Ltd.), "DPI-101", "DPI-102" "DPI-103", "DPI-105", "MPI-103", "MPI-105", "BBI-101", "BBI-102", "BBI-103", "BBI-105", " TPS-101 "," TPS-102 "," TPS-103 "," TPS-105 "," MDS-103 "," MDS-105 "," DTS-102 "and" DTS-103 "(above, Midori Kagaku Co., Ltd. product, "PI-2074" (made by Rhodia Corporation), etc. are mentioned.

Each of these photocationic polymerization initiators may be used alone or in combination with one or more other species. Among these, aromatic sulfonium salts are particularly preferably used because they have excellent UV absorbing properties even in a wavelength range of 300 nm or more, and can provide a cured product having good mechanical strength and adhesive strength.

The compounding quantity of a photocationic polymerization initiator is 0.5-20 weight part normally with respect to 100 weight part of epoxy resins, Preferably it is 1 weight part or more, More preferably, it is 15 weight part or less.

When the compounding quantity of a photocationic polymerization initiator is less than 0.5 weight part with respect to 100 weight part of epoxy resins, hardening becomes inadequate and there exists a tendency for mechanical strength and adhesive strength to fall. Moreover, when the compounding quantity of a photocationic polymerization initiator exceeds 20 weight part with respect to 100 weight part of epoxy resins, since the ionic substance in hardened | cured material increases, the hygroscopicity of hardened | cured material may become high and durability performance may fall.

When using a photocationic polymerization initiator, curable epoxy resin composition which is an adhesive can contain a photosensitizer further as needed. By using a photosensitizer, the reactivity of cationic polymerization can improve and the mechanical strength and adhesive strength of hardened | cured material can be improved. As a photosensitizer, a carbonyl compound, an organic sulfur compound, a persulfide, a redox type compound, an azo and a diazo compound, a halogen compound, a photoreductive dye etc. are mentioned, for example.

More specific examples of the photosensitizer include benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, and α, α-dimethoxy-α-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-chloro thioxanthone and 2-isopropyl thioxanthone; Anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone; Acridon derivatives such as N-methylacridone and N-butylacridone; Others include α, α-diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compounds, halogen compounds and the like. Each of these photosensitizers may be used alone or in combination with one or more of them. It is preferable to contain a photosensitizer in the range of 0.1-20 weight part in 100 weight part of curable epoxy resin compositions.

On the other hand, as a thermal cationic polymerization initiator, a benzyl sulfonium salt, a thiophenium salt, a thiornium salt, benzyl ammonium, a pyridinium salt, a hydrazinium salt, a carboxylic acid ester, a sulfonic acid ester, an amine imide, etc. are mentioned. These thermal cationic polymerization initiators can be easily obtained as a commercial item, for example, "Adeka Opton CP77" and "Adeka Opton CP66" (above, the Adeka Corporation make), "CI" are all brand names, -2639 "and" CI-2624 "(above, Nippon Soda Kabushiki Co., Ltd.)," Sunade SI-60L "," Sunade SI-80L ", and" Sunade SI-100L "(above, Sanshin Kagaku High School) KK Corporation) etc. are mentioned.

The epoxy resin contained in the adhesive may be cured by either photo cationic polymerization or thermal cationic polymerization, or may be cured by both photo cationic polymerization and thermal cationic polymerization. In the latter case, it is preferable to use a photocationic polymerization initiator and a thermal cationic polymerization initiator together.

The curable epoxy resin composition may further contain a compound that promotes cationic polymerization such as oxetane and polyols.

Oxetanes are compounds having a four-membered ring ether in the molecule, for example, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl ] Benzene, 3-ethyl-3- (phenoxymethyl) oxetane, di [(3-ethyl-3-oxetanyl) methyl] ether, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane And phenol novolac oxetane. These oxetanes can be easily obtained as a commercial item, For example, all are brand names, such as "Aronoxetane OXT-101", "Aronoxetane OXT-121", "Aronoxetane OXT-211", "Aron oxetane OXT-221" and "Aron oxetane OXT-212" (above, Toagosei Co., Ltd. product) etc. are mentioned. These oxetanes are contained in curable epoxy resin composition normally in the ratio of 5-95 weight%, Preferably it is 30-70 weight%.

As polyol, it is preferable that acidic groups other than a phenolic hydroxyl group do not exist, For example, the polyol compound which does not have functional groups other than a hydroxyl group, a polyester polyol compound, a polycaprolactone polyol compound, the polyol compound which has a phenolic hydroxyl group And polycarbonate polyols. The molecular weight of these polyols is 48 or more normally, Preferably it is 62 or more, More preferably, it is 100 or more, More preferably, it is 1,000 or less. These polyols are usually contained in the ratio of 50 weight% or less, Preferably it is 30 weight% or less in curable epoxy resin composition.

In addition, as long as the effect of this invention is not impaired in curable epoxy resin composition, other additives, such as an ion trap agent, antioxidant, a chain transfer agent, a sensitizer, a tackifier, a thermoplastic resin, a filler, a flow regulator, A plasticizer, an antifoamer, etc. can be mix | blended. Examples of the ion trapping agent include inorganic compounds such as powdered bismuth-based, antimony-based, magnesium-based, aluminum-based, calcium-based, titanium-based, and mixtures thereof, and examples of the antioxidant include, for example, Hindered phenol type antioxidant etc. are mentioned.

Coated the adhesive agent which consists of curable epoxy resin composition containing the above epoxy resins to one or both of the adhesive surfaces of a polarizing film and a transparent protective film, and one or both of the adhesive surfaces of a polarizing film and a 1st phase difference film. Thereafter, the unbonded adhesive layer is cured by bonding at the surface on which the adhesive is coated and irradiating or heating an active energy ray, so that the transparent protective film is a polarizing film and the first retardation film is a polarizing film, respectively. It can join together through the adhesive bond layer which consists of hardened | cured material layer of curable epoxy resin composition. As a coating method of an adhesive agent, various coating methods, such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater, are employ | adopted, for example.

The adhesive agent containing the epoxy resin used in order to adhere | attach the 1st phase difference film 103 which consists of a transparent protective film 102 and olefin resin to the polarizing film 101 basically does not contain a solvent component substantially. Although it can use as a non-solvent type adhesive agent, since each coating system has the optimum viscosity range, respectively, you may contain a solvent for viscosity adjustment. It is preferable to remove the solvent for viscosity adjustment by heat-processing etc., after hardening an adhesive agent after coating on a film.

It is preferable to use what melt | dissolves an epoxy resin composition satisfactorily as a solvent, without reducing the optical performance of a polarizing film, For example, organic solvents, such as hydrocarbons represented by toluene and esters represented by ethyl acetate, are used. Can be mentioned.

In the case of curing the adhesive by irradiation of active energy rays, the light source used is not particularly limited. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, and a chemical lamp having a light emission distribution at a wavelength of 400 nm or less. , Black light lamps, microwave-excited mercury lamps, metal halide lamps and the like. Although the light irradiation intensity with respect to curable epoxy resin composition may differ for every composition, it is preferable that the irradiation intensity of the wavelength range effective for activation of a photocationic polymerization initiator is 0.1-100 mW / cm <^2> . When the light irradiation intensity to the curable epoxy resin composition is less than 0.1 mW / cm ^{2, the} reaction time is long, and when it exceeds 100 mW / cm ² , it is curable by heat generated from the lamp and heat generated during polymerization of the curable epoxy resin composition. Yellowing of an epoxy resin composition and deterioration of a polarizing film may occur. Although the light irradiation time with respect to curable epoxy resin composition is controlled for every composition, it does not restrict | limit especially, It is preferable to set so that the accumulated light quantity expressed as a product of irradiation intensity and irradiation time may be 10-5,000 mJ / cm <^2>. Do.

When accumulated light amount with respect to curable epoxy resin composition is less than 10 mJ / cm <^2> , generation | occurrence | production of the active species derived from a photocationic polymerization initiator will not be enough, and hardening of an adhesive agent may become inadequate. Moreover, when accumulated light amount exceeds 5,000 mJ / cm < ² >, irradiation time may become very long and it may become disadvantageous for productivity improvement.

When hardening an adhesive agent by heat, it can heat with a generally known method, and the conditions are not specifically limited, either, The temperature at which the thermal cationic polymerization initiator mix | blended with curable epoxy resin composition produces a cationic species or Lewis acid normally. Heating is performed as mentioned above, and heating temperature is about 50-200 degreeC specifically ,.

Even when curing under conditions of irradiation or heating of active energy rays, the polarization degree, transmittance and color of the polarizing film, transparency and phase difference characteristics of the first retardation film made of a transparent protective film and an olefin resin, and various functions of the polarizing plate It is preferable to harden | cure in the range which does not fall.

Second Retardation Film

In the second retardation film 105, the core layer 31 is made of styrene resin, and the skin layer 32 made of a (meth) acrylic resin composition containing rubber particles on both surfaces thereof is formed.

The styrene resin constituting the core layer 31 may be a homopolymer of styrene or a derivative thereof, and may be a binary or higher copolymer of styrene or a derivative thereof with another copolymerizable monomer. Here, the styrene derivative is a compound in which another group is bonded to styrene, for example, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, o-ethyl styrene, p-ethyl styrene Substituted styrene in which a hydroxyl group, an alkoxy group, a carboxyl group, a halogen, etc. are introduced into the benzene nucleus of styrene, such as alkyl styrene, hydroxy styrene, tert-butoxy styrene, vinyl benzoic acid, o-chloro styrene, and p-chloro styrene Can be mentioned. Terpolymers such as those disclosed in JP2003-50316-A or JP2003-207640-A can 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. It is preferable to comprise the styrene resin of a core layer with a heat resistant thing, and generally the Tg is 100 degreeC or more. More preferable Tg of styrene resin is 120 degreeC or more.

It is preferable to set the core layer 31 which consists of styrene resins so that the thickness may be 10-100 micrometers. When the thickness is less than 10 micrometers, sufficient retardation value may be hard to express by extending | stretching. On the other hand, when the thickness exceeds 100 μm, the impact strength of the film tends to be weak, and the retardation change due to external stress tends to be large, and white color fading and the like tends to occur when applied to a liquid crystal display device. It is easy to lose display performance.

The skin layer 32 arrange | positioned on both surfaces of the core layer 31 which consists of said styrene resin consists of the (meth) acrylic-type resin composition in which rubber particle is mix | blended with (meth) acrylic-type resin.

Here, as (meth) acrylic-type resin, the homopolymer of methacrylic acid alkylester or acrylate alkylester, the copolymer of methacrylic acid alkylester, and acrylate alkylester etc. are mentioned, for example. Specific examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and the like. Specific examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, and propyl acrylate. What is marketed as general purpose (meth) acrylic-type resin can be used for such (meth) acrylic-type resin. Moreover, what is called impact-resistant (meth) acrylic-type resin in the (meth) acrylic-type resin, and also what is called high heat-resistant (meth) acrylic-type resin which has a glutaric anhydride structure and a lactone ring structure in a principal chain are included.

It is preferable that the rubber particle mix | blended with (meth) acrylic-type resin is an acryl-type thing. Acrylic rubber particles are particles having rubber elasticity obtained by polymerizing an acrylic acid ester such as butyl acrylate or 2-ethylhexyl acrylate as a main component in the presence of a polyfunctional monomer. Such rubber elastic particles may be formed in a single layer, or may be a multilayer structure having at least one rubber elastic layer. As the acrylic rubber particles having a multi-layered structure, particles having rubber elasticity as described above are used as the nucleus, and the surroundings are covered with a hard alkyl methacrylate polymer, and the hard alkyl methacrylate polymer is used as the nucleus. The periphery thereof was covered with an acrylic polymer having rubber elasticity as described above, and the periphery of the hard nucleus was covered with an acrylic polymer having rubber elasticity, and the periphery of the hard alkyl methacrylate polymer was further covered. The thing covered with is mentioned.

These rubber particles are in the range of the average diameter of the particle | grains formed from an elastic layer normally about 50-400 nm.

Content of the said rubber particle in the (meth) acrylic-type resin composition which comprises the skin layer 32 is about 5-50 weight part normally per 100 weight part of (meth) acrylic-type resin. Since (meth) acrylic-type resin and acrylic rubber particle are marketed in the state which mixed these, the commercial item can be used. As an example of the commercial item of the (meth) acrylic-type resin in which the acryl-type rubber particle was mix | blended, "HT55X", "Technology (trademark) SO01" etc. which are sold by Sumitomo Chemical Co., Ltd. are mentioned. Such a (meth) acrylic-based resin composition generally has a Tg of 160 ° C or lower, and the preferred Tg is 120 ° C or lower, and even 110 ° C or lower.

It is preferable that the skin layer 32 which consists of a rubber particle, Preferably the (meth) acrylic-type resin composition which acryl-type rubber particle was mix | blended so that the thickness may be 10-100 micrometers. If the thickness is intended to be less than 10 m, the film forming tends to be difficult. On the other hand, when thickness exceeds 100 micrometers, there exists a tendency for the retardation of this (meth) acrylic-type resin layer to be unable to be ignored.

As mentioned above, in the 2nd phase difference film 105 used by this invention, it is preferable that the Tg of the core layer 31 which consists of styrene resins is 120 degreeC or more, On the other hand, (meth) in which rubber particle was mix | blended It is preferable that the Tg of the skin layer 32 which consists of acrylic resin compositions is 120 degrees C or less, Furthermore, it is 110 degrees C or less. It is preferable that both Tg does not overlap and the core layer 31 which consists of styrene resins has higher Tg than the skin layer 32 which consists of the (meth) acrylic-type resin composition in which rubber particle was mix | blended.

The second retardation film 105 used in the present invention can be produced, for example, by coextruding a (meth) acrylic resin composition in which styrene resin and rubber particles are blended and then stretching. In addition, after producing each film of a single layer, the method of heat | fusing by heat-lamination and extending | stretching it is also possible.

In this 2nd retardation film 105, it becomes a three-layered structure in which the skin layer 32 which consists of the (meth) acrylic-type resin composition in which rubber particle was mix | blended on both surfaces of the core layer 31 which consists of styrene resins. In this three-layer structure, the skin layers 32 disposed on both surfaces are usually almost the same thickness. Thus, by setting it as a three-layer structure, the skin layer 32 which consists of the (meth) acrylic-type resin composition with which rubber particle was mix | blended functions as a protective layer, and becomes excellent in mechanical strength and chemical-resistance.

In-plane retardation is given to the 2nd phase difference film 105 comprised as mentioned above by extending | stretching. Stretching can be performed by known longitudinal uniaxial stretching, tenter transverse uniaxial stretching, simultaneous biaxial stretching, sequential biaxial stretching, or the like, and stretching may be performed so that a desired retardation value is obtained.

In the second retardation film 105 used in the present invention, it is preferable that the in-plane retardation Re is 20 to 120 nm, and the refractive index anisotropy in which the Nz coefficient defined by the above expression (5) is greater than -2 and less than -0.5.

When laminating | stacking the 1st phase difference film 103 and the 2nd phase difference film 105, the change of the angle which the orientation angle of the 1st phase difference film 103 and the 2nd phase difference film 105 makes is 0.4 degrees between 10 cm. It is preferable to make it become the following. When the change of the angle formed by the alignment angle exceeds 0.4 °, the polarization state changes locally sharply, and thus it is observed as color unevenness when mounted on the liquid crystal display device. Here, an orientation angle means the orientation in which the refractive index in each site | part of each film is the largest.

In the stretched film, generally, the axis | shaft which refractive index becomes largest in surface is called a slow axis, but when it sees in detail, this axis | shaft may be delicately changed in each site | part, and such an orientation angle is also defined simultaneously. Orientation angle can be measured using the commercially available retarder or inspection apparatus, for example, the retardation film and optical material inspection apparatus RETS made from Otsuka Electronics Co., Ltd. make. In order to make the change (deviation) of the angle which the orientation angle of the 1st retardation film 103 and the 2nd retardation film 105 make | form becomes small as mentioned above, for example, the 1st retardation film 103 and the 2nd It is preferable to use the film with small deviation of an orientation angle with respect to each of retardation film 105. As shown in FIG.

[adhesive]

A second retardation film having a structure in which both surfaces of the first retardation film 103 made of olefin resin and the core layer 31 made of styrene resin are sandwiched between the skin layers 32 and 32 made of acrylic resin ( 105 is laminated through the adhesive 104. The thickness of the adhesive layer 104 is about 5-100 micrometers normally, Preferably it is 5-40 micrometers. If the pressure-sensitive adhesive layer is too thin, the adhesiveness is lowered, and if the pressure-sensitive adhesive layer is too thick, problems such as sticking out of the pressure-sensitive adhesive tend to occur. A well-known adhesive can be used for forming the adhesive layer 104, Usually, acrylic resin, styrene resin, silicone resin, etc. are used as a base resin, and there exist an isocyanate compound, an epoxy compound, an aziridine compound, etc. It consists of the composition which added the crosslinking agent and added the silane coupling agent etc. as needed.

[Liquid crystal display device]

As for the composite polarizing plate 100 comprised as mentioned above, the adhesive layer 108 is arrange | positioned on the outer side of the 2nd phase difference film 105, and it can make it possible to join to a liquid crystal cell. In addition, it is common for the separator 109 to be bonded to the outer side of the adhesive layer 108, and temporary adhesive protection of the adhesive layer 108 until use. The composite polarizing plate 100 is laminated on at least one side of the liquid crystal cell to form a liquid crystal display device. When applying to a liquid crystal display device, after peeling the separator 109, it is bonded by the adhesive layer 108 to a liquid crystal cell.

This composite polarizing plate may be disposed on both sides of the liquid crystal cell, 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. 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 have a configuration in which the composite polarizing plate of the present invention is disposed on both sides of the liquid crystal cell, or a structure in which the composite polarizing plate of the present invention is disposed 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 a horizontal electric field mode.

In the liquid crystal display device of the present invention, when the composite polarizing plate of the present invention is disposed on one side of a liquid crystal cell, on the other side, the in-plane retardation Re is 10 nm or less and the absolute value of the thickness direction retardation Rth is 15 nm or less. It is preferable to arrange | position the polarizing plate which has a protective film on the liquid crystal cell side. More preferably, Re is 5 nm or less, and the absolute value of Rth is 10 nm or less of the liquid crystal cell side protective film of this polarizing plate.

As a material used for the transparent protective film which satisfy | fills the requirements that in-plane retardation Re is 10 nm or less and the absolute value of thickness direction retardation Rth is 15 nm or less, For example, a cellulose resin, cyclic olefin resin, (meth) Acrylic resin, ethylene terephthalate resin, propylene resin, etc. are mentioned.

[Example]

Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited by these examples. "Part" and "%" which show usage-amount or content in an example are a basis of weight unless there is particular notice. In addition, the film thickness, in-plane and thickness direction retardation, and Nz coefficient were measured with the following method.

[Measurement of Thickness]

The thickness of the film was measured using the digital micrometer MH-15M by Nikon Corporation.

[Measuring method of in-plane retardation, thickness direction retardation, and Nz coefficient]

In-plane retardation Re, thickness direction retardation Rth and the light of wavelength 590 nm at 23 degreeC using retarder cobra (KOBRA) -21ADH based on the parallel Nicole rotation method by Keio Co., Ltd. make. Nz coefficients were measured.

First, a second retardation film having a three-layer structure in which a skin layer made of a (meth) acrylic resin composition containing rubber particles is formed on both surfaces of a core layer made of an adhesive, an adhesive, and a styrene resin used in Examples and Comparative Examples. An example of the preparation will be described.

[Production of Water-based Adhesive]

3 parts of carboxyl group-modified polyvinyl alcohol [KL-318 by Kuraray Co., Ltd.] is melt | dissolved with respect to 100 parts of water, and the polyamide epoxy clock additive [Sumika Chemtech Co., Ltd.] which is a water-soluble epoxy compound in the aqueous solution. 1.5 parts of manufactured Sumirez resin 650 (30) and solid content concentration 30%] were added, and it was set as the water-based adhesive agent.

[Production of Adhesives 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 (diphenylsulfonio) diphenyl as photocationic polymerization initiator After mixing 2.2 parts of sulfidebis (hexafluorophosphate), it was degassed and the adhesive which consists of curable epoxy resin composition was obtained.

In addition, the photocationic polymerization initiator was mix | blended as a 50% propylene carbonate solution.

[Manufacture of Acrylic Adhesive]

The organic solvent solution which urethane acrylate oligomer and the isocyanate type crosslinking agent were mix | blended with the copolymer of butyl acrylate and acrylic acid was dried by the die coater on the mold release surface of the polyethylene terephthalate film (separator) of 38 micrometers in thickness which the mold release process performed. The coating was carried out so that the subsequent thickness was 25 μm, dried, and an acrylic pressure-sensitive adhesive.

[Production of Second Retardation Film Comprising a Three-Layer Structure]

(Phase difference film A)

Meta which styrene-maleic anhydride copolymer resin ("Dirak (trademark) D332" made from Nova Chemical Co., Ltd. ", Tg = 131 degreeC) is made into the core layer, and about 20% of acrylic rubber particles with an average particle diameter of 200 nm are mix | blended. Three layers of co-extrusion was carried out using a krill resin ("Technololy® S001" manufactured by Sumitomo Chemical Co., Ltd., Tg = 105 ° C) as a skin layer, and skin layers were formed on both surfaces of the core layer. A resin three layer film was obtained. This resin 3-layer film was stretched and the retardation film of Re = 47.3 nm and Nz coefficient = -1.06 was produced. Let this be retardation film A.

(Retardation Film B)

The same resin 3 layer film used for preparation of said retardation film A was extended | stretched, and the retardation film of Re = 47.3 nm and Nz coefficient = -0.98 was produced. Let this be the retardation film B. FIG.

(Retardation Film C)

The same resin 3 layer film used for preparation of said retardation film A was extended | stretched, and the retardation film of Re = 55.0 nm and Nz coefficient = -1.1 was produced. Let this be the retardation film C.

Example 1

(A) Preparation of Composite Polarizer

A 75 μm-thick polyvinyl alcohol film composed 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 manner and further maintained in a strained state at 60 ° C. for 1 minute. After immersion, the solution was immersed in an aqueous solution having a weight ratio of iodide / potassium iodide / water of 0.05 / 5/100 for 60 seconds at 28 ° C., and then for 300 seconds at 72 ° C. in an aqueous solution of potassium iodide / boric acid / water of 8.5 / 8.5 / 100. It was immersed. Subsequently, after wash | cleaning for 20 second with the pure water of 26 degreeC, it dried at 65 degreeC and obtained the polarizing film in which iodine adsorption-orientated to polyvinyl alcohol.

On one side of this polarizing film, a triacetyl cellulose film having a thickness of saponification treatment was bonded to the surface as a transparent protective film, and on the other side, it was obtained from Nihon Xeon Co., Ltd. as a first retardation film. As a film which consists of cyclic olefin resin of thickness 38.6 micrometers, the thing of Re = 74.2 nm and Nz coefficient = 1.41 was bonded so that the absorption axis of a polarizing film and the fastening axis of a 1st phase difference film might be parallel, and the polarizing plate was produced. For bonding, the transparent protective film and the first retardation film were adhered to the polarizing film by drying at 80 ° C. for 5 minutes after bonding using the aqueous adhesive described above, respectively. The obtained polarizing plate was cured at 40 degreeC after that for 168 hours.

The above retardation film A is bonded to the first retardation film side of the polarizing plate obtained as the second retardation film using an acrylic pressure-sensitive adhesive so that the absorption axis of the polarizing film and the fastening axis of the second retardation film are parallel to each other. The polarizing plate was produced.

(B) Fabrication and Evaluation of Liquid Crystal Display

The backlight was detached from a liquid crystal display device (VIERA manufactured by Panasonic Co., Ltd. (model number: TH-37LZ85)) containing a liquid crystal cell of IPS mode, and the polarizing plate disposed on the backlight side of the liquid crystal cell was removed. It removed and the glass surface was wash | cleaned. Next, the composite polarizing plate produced in the above (A) on the backlight side of the liquid crystal cell is acryl-based so that the absorption axis thereof is the same as the absorption axis of the polarizing plate originally arranged, and the second retardation film is on the liquid crystal cell side. A liquid crystal panel was prepared by bonding through an adhesive. Finally, the back light once removed was put back together and the liquid crystal display device was assembled.

About this liquid crystal display device, the distribution ratio of the contrast ratio measured using the liquid crystal viewing angle measuring apparatus "EZ contrast 88XL" by ELDIM company 30 minutes after turning on a backlight was shown in FIG. In the figure, the numbers on the horizontal axis represent polar angles, the numbers on the circumference represent azimuth angles, and the distribution of contrast ratios is expressed in black and white shades corresponding to the contrast ratios of the scale shown on the right side (FIGS. 3 to 7). Same). The contrast ratio of 192 was shown in the position (circle notation in a figure) of azimuth 135 degree and polar angle 60 degrees. Here, the contrast ratio is the ratio of the luminance of the white display state to the luminance of the black display state. In addition, the azimuth angle is a value in which the screen right direction is 0 ° and the counterclockwise direction is positive, and the polar angle is the inclination from the screen normal direction.

[Example 2]

(A) Preparation of Composite Polarizer

In Example 1 (A), it is a film which consists of cyclic olefin resin of thickness 29.8 micrometers obtained from Nihon Xeon Co., Ltd., and changed into Re = 79.2 nm, Nz coefficient = 1.21, The second retardation film is changed to the retardation film B described above having a three-layer structure in which a skin layer made of a (meth) acrylic resin composition containing rubber particles is formed on both surfaces of a core layer made of styrene resin. The composite polarizing plate was produced.

(B) Fabrication and Evaluation of Liquid Crystal Display

Except using the composite polarizing plate obtained here, it carried out similarly to Example (B), and produced the liquid crystal display device. About this liquid crystal display device, the distribution ratio of the contrast ratio measured similarly to (B) of Example 1 is shown in FIG. The contrast ratio of 195 was shown in the position (circle in figure) of azimuth 135 degree and polar angle 60 degrees.

Example 3

(A) Preparation of Composite Polarizer and Polarizer

In the same manner as in Example 2 (A), a transparent protective film made of triacetyl cellulose is bonded to one side of the polarizing film, and the other side is made of a cyclic olefin resin having Re = 79.2 nm and Nz coefficient = 1.21. The composite polarizing plate in which the retardation film B which consists of a 3-layered structure in which the skin layer which consists of a (meth) acrylic-type resin composition containing a rubber particle was formed on both surfaces of the 1st retardation film and the core layer which consists of styrene resin was produced.

On the other hand, to one side of the polarizing film produced according to the method shown in the first half of Example 1 (A), a triacetyl cellulose film having a thickness of saponification was applied to the surface was bonded to the surface, and the other side had a thickness of 40 A transparent protective film [KC4UEW manufactured by Konica Minolta Opto Co., Ltd.] of Rem = 0.7 nm and Rth = -0.1 nm is bonded to each other, and a transparent protective film made of triacetyl cellulose is laminated on both surfaces. A polarizing plate was prepared. Both surfaces of the transparent protective film were adhered to the polarizing film by drying at 80 ° C. for 5 minutes using the water-based adhesives described above, respectively.

(B) Fabrication and Evaluation of Liquid Crystal Display

The backlight was removed from the liquid crystal display device including the liquid crystal cell of the same IPS mode as used in Example 1 (B), the polarizing plates on both sides of the liquid crystal cell were removed, and the glass surface thereof was washed. Next, the polarizing plate shown in the latter half of said (A) is 40 micrometers in thickness on the visible side of a liquid crystal cell so that the 2nd retardation film may become the liquid crystal cell side in the composite polarizing plate shown in the first half of said (A) on the backlight side of this liquid crystal cell. A triacetyl cellulose film was bonded through an acrylic pressure-sensitive adhesive so that the triacetyl cellulose film was on the liquid crystal cell side and the same as the absorption axis of the polarizing plate on which each absorption axis was originally arranged, thereby producing a liquid crystal panel. Finally, the back light once removed was put back together and the liquid crystal display device was assembled.

About this liquid crystal display device, the distribution diagram of the contrast ratio measured similarly to Example (B) is shown in FIG. The contrast ratio of 195 was shown in the position (circle in figure) of azimuth 135 degree and polar angle 60 degrees.

Example 4

(A) Preparation of Composite Polarizer and Polarizer

In the same manner as in Example 2 (A), a transparent protective film made of triacetyl cellulose is bonded to one side of the polarizing film, and the other side is made of a cyclic olefin resin having Re = 79.2 nm and Nz coefficient = 1.21. The composite polarizing plate in which the retardation film B which consists of a 3-layered structure in which the skin layer which consists of a (meth) acrylic-type resin composition containing a rubber particle was formed on both surfaces of the 1st retardation film and the core layer which consists of styrene resin was produced.

On the other hand, to one side of the polarizing film produced according to the method shown in the first half of Example 1 (A), a triacetyl cellulose film having a thickness of saponification was applied to the surface was bonded to the surface, and the other side had a thickness of 40 The polarizing plate which consists of micrometer cyclic olefin resin, Re = 2.1 nm, Rth = 2.8 nm transparent protective film (obtained from Nihon Xeon Co., Ltd.) was bonded together, and the transparent protective film was laminated | stacked on both surfaces. Both surfaces of the transparent protective films were bonded to the polarizing films by drying for 5 minutes at 80 ° C. after the bonding using the aqueous adhesives described above, respectively, and curing was then performed at 40 ° C. for 168 hours.

(B) Fabrication and Evaluation of Liquid Crystal Display

The backlight was removed from the liquid crystal display device including the liquid crystal cell of the same IPS mode as used in Example 1 (B), the polarizing plates on both sides of the liquid crystal cell were removed, and the glass surface thereof was washed. Next, on the visible side of the liquid crystal cell, the polarizing plate shown in the latter half of the above (A) is formed on the visible side of the liquid crystal cell so that the second phase difference film is the liquid crystal cell side on the backlight side of the liquid crystal cell. A liquid crystal panel was produced by adhering through an acrylic pressure-sensitive adhesive so that the protective film made of μm cyclic olefin resin was on the side of the liquid crystal cell, and the respective absorption axes were the same as the absorption axes of the polarizing plates originally arranged. Finally, the back light once removed was put back together and the liquid crystal display device was assembled.

About this liquid crystal display device, the distribution ratio of the contrast ratio measured similarly to Example (B) of FIG. 1 is shown in FIG. The contrast ratio of 195 was shown in the position (circle in figure) of azimuth 135 degree and polar angle 60 degrees.

Comparative Example 1

(A) Preparation of Polarizing Plate

To one side of the polarizing film produced according to the method shown in the first half of Example 1 (A), a triacetyl cellulose film having a thickness of saponification was applied to the surface, and a surface of 40 μm in thickness was attached to the other side. A polarizing plate made of triacetyl cellulose, bonded with a transparent protective film (KC4UEW manufactured by Konica Minolta Opto Co., Ltd.) with Re = 0.7 nm and Rth = -0.1 nm, and laminated with a transparent protective film made of triacetyl cellulose on both sides. Was produced. Both surfaces of the transparent protective film were adhered to the polarizing film by drying at 80 ° C. for 5 minutes after bonding using the above-described water-based adhesive, respectively.

(B) Fabrication and Evaluation of Liquid Crystal Display

Except using the polarizing plate produced here, it carried out similarly to Example (B), and produced the liquid crystal display device. This polarizing plate adhered to the liquid crystal cell on the triacetyl cellulose film side having a thickness of 40 µm. The distribution ratio of the contrast ratio measured about this liquid crystal display device similarly to Example (B) of FIG. 1 is shown in FIG. The contrast ratio of 26 was shown in the position (circle notation in a figure) of azimuth 135 degree and polar angle 60 degrees.

Example 5

(A) Preparation of Composite Polarizer

In Example 1 (A), it is a film which consists of cyclic olefin resin of thickness 35.8 micrometers obtained from Nihon Xeon Co., Ltd., and changed into Re = 76.2nm, Nz coefficient = 1.37, The second retardation film is changed to the retardation film C described above having a three-layer structure in which a skin layer made of a (meth) acrylic resin composition containing rubber particles is formed on both surfaces of a core layer made of styrene resin. In the same manner, a composite polarizing plate was produced.

(B) Fabrication and Evaluation of Liquid Crystal Display

Except using the composite polarizing plate obtained here, it carried out similarly to Example (B), and produced the liquid crystal display device. The distribution diagram of the contrast ratio measured similarly to Example (B) of Example 1 about this liquid crystal display device is shown in FIG. The contrast ratio of 326 was shown in the position of 135 degree azimuth and 60 degree polar angles.

In this liquid crystal display, local color unevenness was seen on the display. Therefore, the composite polarizing plate used is peeled off from the liquid crystal panel, is extracted in the screen width direction centering on the part where local color unevenness is seen, and the 2nd phase difference film which consists of a three-layered structure, and the 1st phase difference film which consists of cyclic olefin resin are provided. It peels and measures the orientation angle of the corresponding site | part in each bonded state over 80 cm of width direction of a screen using the retardation film and optical material inspection apparatus RETS of Otsuka Electronics Co., Ltd., and in each site | part The angle (difference between one orientation angle and another orientation angle) which the orientation angle of makes | forms was computed. The results are shown in Figure 8 (a). The change between 10 cm of the angle which the orientation angle of the two phase difference films used here makes was 0.43 degrees at the maximum.

(C) Fabrication and Evaluation of Other Composite Polarizers and Liquid Crystal Display Devices

On the other hand, although it is the same grade as what was used as said 1st retardation film in said (A), it is a film of another lot [the film which consists of cyclic olefin resin of thickness 35.8micrometer obtained from Nihon Xeon Co., Ltd., Re = 76.2nm, Nz] Coefficient = 1.37] was used, otherwise a composite polarizing plate was produced in the same manner as in the above (A), and a liquid crystal display device was assembled in the same manner as in the above (B) using the same. The distribution of the contrast ratio of this liquid crystal display device is the same as that of FIG. 7, and the contrast ratio is 326 at the azimuth angle of 135 ° and the polar angle of 60 °, and no local color unevenness was observed on the display.

The composite polarizing plate used here was peeled off from the liquid crystal panel, the same part which measured the orientation angle from above was extracted in the screen width direction, and the 2nd phase difference film which consists of a 3-layered structure, and the 1st phase difference film which consists of cyclic olefin resin are peeled off. In each bonded state, the orientation angle of the corresponding site | part is measured over the width direction of 80 cm of screens using the retardation film and optical material inspection apparatus RETS of Otsuka Electronics Co., Ltd. product, and in each site | part The angle (difference between one orientation angle and another orientation angle) which an orientation angle makes was computed. The result is shown in FIG. The change between 10 cm of the angle which the orientation angle of the two phase difference films used here makes was 0.27 degrees at the maximum.

100: composite polarizer
101: polarizing film
102: transparent protective film
103: first retardation film
104: adhesive layer
105: second retardation film
106: first adhesive layer
107: second adhesive layer
108: adhesive layer
109: separator
31: core layer
32: skin layer

Claims (10)

The transparent protective film is laminated | stacked on one side of a polarizing film through a 1st adhesive bond layer, The 1st phase difference film which consists of olefin resin is laminated | stacked on the other side of a polarizing film through a 2nd adhesive bond layer,
The 2nd phase difference film which consists of a 3-layered structure in which the skin layer which consists of (meth) acrylic-type resin composition containing a rubber particle is formed on both surfaces of the core layer which consists of styrene resin through an adhesive layer on the outer side of a 1st phase difference film. Composite polarizer. The method of claim 1, wherein the in-plane retardation in the first retardation film is 30 to 150 nm,
When the refractive indices of the in-plane slow axis direction, the in-plane fast axis direction, and the thickness direction are n _x , n _y, and n _z , respectively, Nz defined by the formula: (n _x -n _z ) / (n _x -n _y ) Has a refractive index anisotropy with a coefficient greater than 1 and less than 2,
In-plane retardation in the second retardation film is 20 to 120 nm,
The composite polarizing plate which has refractive index anisotropy whose Nz coefficient defined as above is more than -2 and less than -0.5. The composite polarizing plate of Claim 1 or 2 laminated | stacked so that the change of the angle which the orientation angle of a 1st phase difference film and a 2nd phase difference film may make may be 0.4 degrees or less between 10 cm. The composite polarizing plate according to any one of claims 1 to 3, wherein the olefin resin is a cyclic olefin resin containing a structural unit derived from an alicyclic olefin. The second retardation film comprises a core layer made of a styrene resin having a glass potential temperature of 120 ° C. or higher, and a (meth) acrylic resin composition having a glass potential temperature of 120 ° C. or lower. Composite polarizing plate composed of a skin layer. The composite polarizing plate according to any one of claims 1 to 5, wherein the second adhesive layer is made of an aqueous adhesive containing a polyvinyl alcohol-based resin and an epoxy compound. The composite polarizing plate of any one of Claims 1-5 in which the 2nd adhesive bond layer consists of hardened | cured material layer of the epoxy resin composition containing the epoxy resin hardened | cured by irradiation or heating of an activation energy ray. The composite polarizing plate according to claim 7, wherein the epoxy resin contains a compound having one or more epoxy groups in the molecule bonded to an alicyclic ring. The IPS mode liquid crystal display device in which the composite polarizing plate of any one of Claims 1-8 is arrange | positioned on at least one surface of an IPS mode liquid crystal cell. The composite polarizing plate according to any one of claims 1 to 8 is disposed on one side of the IPS mode liquid crystal cell, and on the other side, the in-plane retardation is 10 nm or less and the thickness direction retardation The IPS mode liquid crystal display in which the polarizing plate which has the transparent protective film whose absolute value is 15 nm or less on the liquid crystal cell side is arrange | positioned.

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