JPH1195030A - Phase difference film and liquid crystal display device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase difference film excellent in durability and having a uniform optical characteristic in large area, with the retardation value within a film face being smaller than the retardation value in the thickness direction of the film by providing a layer containing at least one kind of organic clay complex dispersible in an organic solvent. SOLUTION: A phase difference film has at least one layer containing at least one kind of organic clay complex dispersible in an organic solvent. As the organic clay complex, there is a compound obtained by compounding clay mineral of laminated structure and an organic compound, for instance. The clay mineral of laminated structure normally has an oxygen atom or hydroxyl group of Si-O, Si-OH or Al-OH existing on the surface, and exchangeable cation and its hydration ion occupies a space between crystal layers. The organic clay complex is obtained by a method of compounding by making the oxygen atom or hydroxyl group react on the organic compound, and a method of compounding by exchanging the exchangeable cation with organic ion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a retardation film having improved durability and a liquid crystal display using the same.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 5-196819 discloses a retardation film in which the refractive index in the film plane and the refractive index in the film thickness direction are different. The inorganic layered compound used in the retardation film has a unit crystal layer having a planar structure. Therefore, when formed on a transparent resin substrate alone or in a mixed state with a resin, the unit crystal layer forms a transparent resin. The orientation parallel to the surface of the substrate and in the plane is randomly oriented. As a result, this retardation film has a refractive index structure in which the refractive index in the film plane is larger than the refractive index in the thickness direction, and the in-plane retardation value is smaller than the retardation value in the film thickness direction. Will be shown.

An inorganic layered compound layer formed on an isotropic transparent resin substrate has optical characteristics such that the in-plane retardation value is almost 0 nm and the retardation value in the thickness direction is larger. Then, a retardation value in the thickness direction [R ′ = (n _XY −n _z ) ·
d (n _XY : average refractive index in the plane of the film, n _z : refractive index in the thickness direction, d: thickness of the film)] can be easily controlled to a predetermined value, and a large area and uniform retardation film can be produced. be able to. This retardation film can be used for improving the viewing angle characteristics of a vertical alignment nematic (VAN) type liquid crystal display device and a 90-degree twisted nematic (TN) type liquid crystal display device. In addition, an inorganic layered compound layer is directly formed on a uniaxially oriented film such as polystyrene having a negative refractive index anisotropy as a transparent resin substrate, or an inorganic layered compound layer is formed on an isotropic transparent resin substrate. After that, using a pressure-sensitive adhesive to bond the film to a uniaxially oriented film such as polystyrene having a negative refractive index anisotropy, the retardation value in the film plane (R) and the slow axis are defined as tilt axes. 4
0 degree inclined retardation value measured by the ratio of _{(R 40) (R 40 /} R) can be controlled in the range of 0.9 to 1.1, super twisted nematic (STN) type by using the The viewing angle characteristics of the liquid crystal display device can also be improved. Further, an inorganic layered compound layer is directly formed on a uniaxially oriented film such as polycarbonate having a positive refractive index anisotropy as a transparent resin substrate, or an inorganic layered compound layer is formed on an isotropic transparent resin substrate. After the film is formed, R ₄₀ / R is adjusted to 1.1 by a method such as bonding the film to a uniaxially oriented film such as polycarbonate having a positive refractive index anisotropy using an adhesive.
Optical birefringence compensation (OCB) type liquid crystal display such as a bend alignment nematic (π cell) type liquid crystal display or a hybrid alignment nematic (HAN) type liquid crystal display. The viewing angle characteristics of the device can also be improved.

In the production of this retardation film, a water-soluble resin and an inorganic layered compound are used in view of the ease of forming an inorganic layered compound layer on a transparent resin substrate, the development of optical properties and the mechanical properties. It is preferable to use a combination of the above. In particular, a method of applying a water dispersion containing polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound on a transparent resin substrate to form a film is preferably used.

However, the retardation film disclosed in Japanese Patent Application Laid-Open No. Hei 5-96819, in which an aqueous dispersion of a polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound is formed on a transparent resin substrate, has a problem in optical characteristics. Although excellent, in a high-temperature, high-humidity environment in a state where a retardation film is sandwiched between a polarizing plate and a liquid crystal cell, in a high-humidity environment, a layer composed of polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound is formed. In some cases, poor durability may occur due to peeling from the transparent resin substrate.

This poor durability mainly involves the use of a hydrophilic compound such as a water-soluble resin and a water-swellable inorganic layered compound. It is considered that this is due to the fact that a large volume expansion is caused and the adhesion force is reduced due to the softening of the water-soluble resin at the interface. In addition, as a retardation plate using an inorganic layered compound, a handbook of optics [WGDriscoll et al., Optica
l Society of America, McGraw-hill, USA, 1978)], pp. 10-108, sections 57, 58. The in-plane retardation value (R) is λ
/ 4 or the like is known. But,
Since the cleavage property of the crystal is used, it is difficult to obtain a large area and uniform material which can be used for a liquid crystal display device or the like. In addition, since the ratio of the in-plane retardation value to the retardation value in the thickness direction (R ') is made of a single crystal and is constant, when R' is designed to be an arbitrary value, R becomes unique. It is not possible to arbitrarily control R ′ while keeping R small, for example, when R ′ becomes as large as several hundred nm, R exceeds 50 nm.

In view of this situation, the present inventors have conducted intensive studies. As a result, the use of an organoclay composite which can be dispersed in an organic solvent has excellent durability, and the in-plane retardation value of the film in the film thickness direction has a letter value. A retardation film having a smaller optical density than that of the retardation value and having a uniform optical property over a wide area has been developed, and the present invention has been completed.

[0008]

That is, the present invention is as follows. (1) A retardation film having at least one layer containing at least one kind of organic clay composite dispersible in an organic solvent. (2) having at least one layer containing at least one kind of organoclay composite dispersible in an organic solvent, having an in-plane retardation value of 50 nm or less and an in-plane retardation value in the film thickness direction; Retardation film smaller than the retardation value. (3) A layer containing at least one kind of organoclay composite dispersible in an organic solvent is formed on at least one surface of a transparent resin substrate, and the retardation value in the film surface is 50.
A retardation film having a retardation value of not more than nm and an in-plane retardation value smaller than a retardation value in a film thickness direction. (4) A liquid crystal display comprising at least one retardation film according to (1), (2) or (3).

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As an organoclay composite, for example,
Compounding of clay mineral with layered structure and organic compound
And the like. Clay minerals with a layered structure
Usually, the surface has Si-O, Si-OH or Al-O
There is an oxygen atom or a hydroxyl group of H, and between the crystal layers
Occupied by exchangeable cations and their hydrated ions. This
By reacting organic compounds with oxygen atoms or hydroxyl groups
Combination method and exchange of exchangeable cations with organic cations
Can be made into an organoclay composite by a method of compounding
it can. Smectite family, a kind of clay mineral, and swelling property
Mica replaces Si in the tetrahedral layer of the crystal structure with Al or Fe (II
I), Al in the octahedral layer is replaced with Si or Fe (III),
Mg is isomorphically substituted for Li, and the resulting negative
Of the layer charge of Na ⁺, K⁺, Ca²⁺, Mg²⁺And A
l³⁺Such as exchangeable cations. These clays
Minerals have a relatively weak bond between unit crystal layers,
Easy to spread, colloidal when dispersed in water, etc.
Swells between unit crystal layers to form sol in water until
And exhibit cation exchange capacity. With organic compounds
This cation exchange is effective for complexation,
The tribes are relatively small in layer charge relative to other clay minerals and are easy
Sol can be formed at high cation exchange capacity.
It is preferably used for production. Smectites are also transparent.
Excellent in lightness and used as a retardation film
preferable.

Examples of those belonging to the smectite family include hectorite, montmorillonite, bentonite, and the like, substituted substances, derivatives and mixtures thereof.
Among them, those chemically synthesized are preferably used for the retardation film from the viewpoint that they have few impurities and are excellent in transparency. In particular, synthetic hectorite whose particle size is controlled to be small is preferably used because scattering of visible light is suppressed.

Examples of the organic compound include a compound capable of reacting with an oxygen atom or a hydroxyl group of a clay mineral and an ionic compound capable of exchanging with an exchangeable cation. The organic viscosity complex swells and disperses in an organic solvent. There is no particular limitation as long as it can be used, and examples thereof include amine compounds. Examples of the amine compound include a quaternary ammonium compound, urea, hydrazine, doditerpyridinium and the like.

Since cation exchange is easy, 4
A secondary ammonium compound is preferably used. The quaternary ammonium compound is usually introduced as a cation, such dimethyl dioctadecyl.
Those having an alkyl group or a benzyl group such as ammonium ion, dimethyl benzyl octadecyl ammonium ion, trioctyl methyl ammonium ion, etc., methyl diethyl polyoxypropylene (polymerization degree: 25), ammonium ion, etc. And those having a long-chain substituent as described above.

These organic compounds are desirably used in an equivalent amount to the cation exchange capacity of the clay mineral, but are added in the range of 0.5 to 1.5 times the cation exchange capacity during production. It does not matter.

[0014] These organoclay composites can be prepared by appropriately selecting an organic compound to be used.
Low-polarity aromatic hydrocarbons such as xylene, acetone,
Easily used in various organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone; lower alcohols such as methanol, ethanol and propanol; and highly polar solvents such as halogenated hydrocarbons such as carbon tetrachloride, chloroform, dichloromethane and dichloroethane. It can be dispersible.

The thus obtained organoclay composite dispersible in an organic solvent exhibits excellent moist heat resistance when it is used as a retardation film. Some organic compounds change color in a high-temperature environment, and it is desirable to control the degree of discoloration within an allowable range.

When the retardation film of the present invention is applied to a liquid crystal display device, usually one or two retardation films are used. It is desirable that one sheet satisfies the allowable range of discoloration, but it is more preferable that two sheets satisfies the allowable range. In the present invention, the permissible range of discoloration is defined as L ^* a ^*.
b ^{* Indicates} that the color difference ΔE ^* between the color before the test in the color system (JIS Z-8729) and the color after 1000 hours in a temperature environment of 80 ° C. is 5 or less.

The thus obtained organoclay complex dispersible in an organic solvent is usually hydrophobic and, when dispersed in an organic solvent, can swell the unit crystal layer until it becomes colloidal. The unit crystal layer can be oriented by coating on a substrate, drying and forming a film, so that it can be used as a retardation film. The concentration of the organoclay complex in the dispersion when forming a layer comprising the organoclay complex on a substrate is preferably as high as possible because the thickness of the layer can be increased, but gelation occurs when the concentration is too high. And the like, and the film-forming property deteriorates.
It is used in the range of 0% by weight. Further, a plurality of these organic clay composites may be used in combination.

When used as a retardation film, it can be peeled off from the formed substrate and used as a single film, but can also be used as it is formed on a transparent substrate using a transparent substrate. When the substrate to be formed is a flat plate, the unit crystal layer of the organoclay composite has its layered structure parallel to the flat plate surface and randomly oriented in the plane. Accordingly, a refractive index structure in which the refractive index in the film plane is larger than the refractive index in the film thickness direction is exhibited. Due to the refractive index anisotropy, the film can be used as a retardation film having an in-plane retardation value of 50 nm or less and an in-plane retardation value smaller than the retardation value in the film thickness direction.

As the transparent resin substrate, an isotropic transparent resin substrate can be used. When an isotropic transparent resin substrate is used, a retardation film having an in-plane retardation value smaller than a retardation value in a film thickness direction is obtained. Such a transparent resin substrate is not particularly limited as long as it is a film having a small orientation and excellent uniformity and having a thickness of 50 to 200 μm, but a film in which the in-plane retardation value is controlled to 20 nm or less is preferred. preferable. Examples of such a film include a cellulose-based film, a polycarbonate-based film, a polystyrene-based film, a polysulfone-based film, an acrylic-based film prepared by a solvent casting method, and an acrylic-based film formed by a low-residual-stress precision extrusion method. Among them, a triacetyl cellulose film formed by a solvent casting method is preferable.

When a uniaxially oriented film having a negative refractive index anisotropy is used as the transparent resin substrate, the in-plane retardation value (R) and the 40 ° tilt angle with the slow axis as the tilt axis. Retardation value (R
₄₀ ) is a retardation film having a ratio (R ₄₀ / R) of 0.9 to 1.1, and can be used as a film for improving viewing angle characteristics of an STN liquid crystal display device. Examples of such a transparent resin substrate include a uniaxially oriented film that can be obtained by forming a polystyrene resin or an acrylic resin having a negative refractive index anisotropy by a solvent casting method and then uniaxially stretching the film. It is preferable to use a polystyrene-based resin from the viewpoint of easily exhibiting retardation. Polystyrene resins include polystyrene, styrene
An acrylonitrile copolymer, an acrylonitrile-butadiene-styrene copolymer and the like can be exemplified.
Further, when a uniaxially oriented positive film having a positive refractive index anisotropy is used as the transparent resin substrate, a retardation film having R ₄₀ / R larger than 1.1 is obtained, and an OCB type liquid crystal display device or the like is used. It can be used as a film having improved viewing angle characteristics. As such a transparent resin substrate, a uniaxially oriented film which can be obtained by forming a polycarbonate resin having a positive refractive index anisotropy, a polyester resin or a polysulfone resin by a solvent casting method and then uniaxially stretching the film. However, it is preferable to use a polycarbonate resin from the viewpoint of easy development of retardation and easy stretching.

Further, from the viewpoint of easy formation on a substrate, development of optical characteristics, mechanical characteristics, and the like, a method using in combination with a hydrophobic resin can be preferably used. The hydrophobic resin used in the present invention is not particularly limited as long as it can be dissolved in an organic solvent capable of dispersing the organoclay composite,
Those that dissolve in low-polarity organic solvents such as benzene, toluene, and xylene are preferably used. Examples of such a hydrophobic resin include polyvinyl acetal resins such as polyvinyl butyral and polyvinyl formal, and cellulose resins such as cellulose acetate butyrate. The organic clay composite is usually hydrophobic, but some of them can be dispersed in a polar solvent.When these are used, in addition to polyacetal resin and cellulose resin, acrylic resin, polycarbonate resin, and polyester resin are used. Resin or the like can also be used. Further, a plurality of these resins may be used in combination.

The composition ratio of the organic clay composite dispersible in the organic solvent to the hydrophobic resin is preferably in the range of 1: 2 to 10: 1 by weight, and the composition ratio of the organic clay composite and the hydrophobic resin is preferably in the range of 1: 2 to 10: 1. It is preferable for improving mechanical properties such as crack prevention.
The solid content concentration of the dispersion is not particularly limited as long as the prepared dispersion does not gel or become turbid for several days after the preparation, but is usually the total solid content of the organoclay composite and the hydrophobic resin. The concentration is used in the range of 3 to 15% by weight. Since the optimum solid content concentration varies depending on the composition ratio of the organic clay composite and the hydrophobic resin, it is set for each composition ratio. Further, an additive such as a viscosity modifier for improving the coating property when forming a film on the substrate and a crosslinking agent for further improving the hydrophobicity and durability may be added.

The retardation film of the present invention can be used for improving the viewing angle characteristics of a VAN type liquid crystal display device, a TN type liquid crystal display device, an STN type liquid crystal display device and an OCB type liquid crystal display device. At least one kind of organoclay composite dispersible in an organic solvent or at least one kind of organoclay composite dispersible in an organic solvent so that an optimal retardation value (R ′) in the thickness direction is obtained by a display device; The thickness after forming the layer containing at least one type of hydrophobic resin is controlled. This thickness is usually set in the range of 1 to 50 μm, depending on the optical characteristics of the organic clay composite dispersible in the organic solvent and the composition ratio of the organic clay composite and the hydrophobic resin.

In the present invention, in order to further enhance the adhesion between the layer containing the organic clay complex dispersible in an organic solvent and the transparent substrate, an anchor coat layer may be provided on the transparent substrate, or the surface of the transparent substrate may be corona-coated. Means such as surface treatment such as treatment is preferably used. As the anchor coat layer,
There is no particular limitation as long as the dispersion containing the organic clay complex dispersible in the organic solvent can be uniformly applied on the substrate and the adhesion can be improved, but a urethane resin, an acrylic resin, or the like can be used. Can be used.

The method of forming a layer comprising an organic clay composite dispersible in an organic solvent, a layer comprising an organic clay composite dispersible in an organic solvent and a hydrophobic resin, and an anchor coat layer on a transparent resin substrate is as follows. There is no particular limitation, and a coating method such as a direct gravure method, a reverse gravure method, a die coating method, a comma coating method, and a bar coating method can be used. Among them, a comma coating method, a die coating method using no backup roll, and the like are preferably used because of excellent thickness accuracy.

The retardation film according to the present invention thus produced has excellent transparency, and usually has a light transmittance of 80% or more necessary for use in a liquid crystal display device.

In applying the retardation film of the present invention to a liquid crystal display device, at least one retardation film of the present invention may be disposed between the polarizing plate and the liquid crystal cell of the liquid crystal display device, and the viewing angle can be reduced. If one optical element is insufficient as an optical characteristic for improvement, two optical elements may be stacked and arranged.
Further, in order to ensure the symmetry of the viewing angle characteristic, the upper and lower polarizers may be divided and disposed between the upper and lower polarizers and the liquid crystal cell.

[0028]

Industrial Applicability According to the present invention, not only excellent optical characteristics but also organic clay composite or organic clay which can be dispersed in an organic solvent which is excellent in durability and which does not cause problems such as peeling in a high temperature and high humidity environment. It is possible to obtain a retardation film having a retardation value in the plane of the film composed of a layer containing an organic clay composite dispersible in a solvent, which is smaller than the retardation value in the film thickness direction. Further, by using the retardation film of the present invention, a liquid crystal display device having not only excellent viewing angle characteristics but also excellent durability can be obtained.

[0029]

The present invention will be described below in detail with reference to examples.
However, the present invention is not limited to this. In addition,
The measurement and evaluation of samples were performed by the following methods. (1) Light transmittance of retardation film: Shimadzu Corporation
It measured using the spectrophotometer UV2200 made from. (2) In-plane retardation of retardation film
Value: R using a polarizing microscope Optiphoto-Pol manufactured by Nikon Corporation
Senarmont method with monochromatic light of wavelength 546 nm
thod). (3) Retardation value in film thickness direction: R'R, R₃₀(Measured at 30 degrees with the slow axis as the tilt axis.
Retardation value), d (thickness of retardation film)
And the average refractive index (set to 1.5) of the retardation film
Using the following formulas (1) to (3),
N _x, N_Y, N_ZAnd then to equation (4)
R ′ was calculated. R = (n_x-N_Y) × d (1) R₃₀= (N_X-N_Y′) × d / cos (φ) (2) (n_X+ N_Y+ N_Z) /3=1.5 (3) R ′ = ((n_X+ N_Y) / 2-n_Z) × d (4) where φ = sin^-1[Sin (30 °) /1.5] = 19.4
71 ° n_y’= N_y× n_z/ (N_y ^Two× sin^Two(Φ) + n_Z ^Two× co
s^Two(Φ))^1/2 (4) Heat-resistant discoloration test: Two retardation films with an adhesive
C light source of a glass plate, hue L at 2 degree field of view
^*a^*b^*About Color Difference Meter CT-2 manufactured by Minolta Co., Ltd.
10 and the initial L^{* 0}a^{* 0}b^{* 0}And 1 at 80 ° C
L after leaving for 000 hours^{* 1}a^{* 1}b^{* 1}And calculate the following equation
Color difference ΔE calculated using^*Was evaluated. ΔE^*= [(L^{* 1}-L^{* 0})^Two+ (A^{* 1}-A^{* 0})^Two+ (B^{* 1}
-B^{* 0})^Two]^1/2 (5) Moisture and heat resistance test: polarizing plate (SK-1842AP7,
Sumitomo Chemical Co., Ltd.) and a liquid crystal cell
(125mm x 95mm)
mm. In-plane with polarizing film absorption axis and retardation film
If there is a retardation value of
The slow axis is 45 ° counterclockwise with respect to the long side
Ring) at a temperature of 60 ° C and a relative humidity of 90%.
Leave for 500 hours under the environment to disperse the organic solvent
Separation at the interface between the layer containing the clay composite and the transparent resin substrate
Was observed to see if any of the above-mentioned problems occurred.

Example 1 Hydrophobic resin (trade name: Denka butyral # 3000-K)
1.75% by weight of Denki Kagaku Kogyo K.K., 3.94% by weight of organoclay composite 1 (trade name: Lucentite STN Corp Chemical Co., Ltd.) and organoclay composite 2 (trade name: Lucentite) 1.31% by weight of SPN Corp. Chemical Co., Ltd., 65.1% by weight of toluene, 18.6% by weight of methylene chloride, and 9.3 of acetone.
An organic solvent dispersion containing 5% by weight (hereinafter referred to as dispersion A) is coated on an isotropic transparent resin substrate (hereinafter referred to as a 80 μm-thick triacetyl cellulose film (trade name: Fujitac SH-80, manufactured by Fuji Photo Film Co., Ltd.)). The substrate was coated with a bar coater such that the film thickness after drying was about 6 μm, and dried in an oven at 85 ° C. to obtain a retardation film according to the present invention. Table 1 shows the optical properties and durability test results of this film.

Example 2 An isotropic transparent resin substrate (hereinafter referred to as substrate b) was prepared by subjecting Dispersion A to a corona-treated 80 μm-thick triacetyl cellulose film (trade name: Fujitac SH-80, manufactured by Fuji Photo Film Co., Ltd.). This was applied on the substrate b using a comma coater so that the film thickness after drying was about 17 μm, and dried at 85 ° C. to obtain a retardation film according to the present invention. Table 1 shows the optical properties and durability test results of this film.

Example 3 A retardation film according to the present invention was obtained in the same manner as in Example 2, except that the thickness of the layer comprising the organic clay composite and the hydrophobic resin of Example 2 after drying was about 48 μm. Table 1 shows the optical properties and durability test results of this film.

Example 4 Dispersion A was coated on one side of an 80 μm-thick triacetyl cellulose film (trade name: Fujitac SH-80, manufactured by Fuji Photo Film Co., Ltd.) with an acrylic UV curable resin as an anchor coat layer of about 5 μm. Is formed on the acrylic resin layer of the substrate c to have a thickness of about 16 on the acrylic resin layer.
It was applied using a bar coater to a thickness of μm and dried in an oven at 85 ° C. to obtain a retardation film according to the present invention. Table 1 shows the optical properties and durability test results of this film.

Example 5 Hydrophobic resin (trade name: Denka butyral # 3000-K)
2.50% by weight of Denki Kagaku Kogyo Co., Ltd., 5.63% by weight of organoclay composite 1 (trade name: Lucentite STN Corp Chemical Co., Ltd.) and organoclay composite 2 (trade name: Lucentite) 1.87% by weight of SPN Corp. Chemical Co., Ltd., 63.0% by weight of toluene, 18.0% by weight of methylene chloride, and 9.0 of acetone.
An organic solvent dispersion containing 5% by weight (hereinafter referred to as dispersion B) was applied on a substrate b using a bar coater so that the film thickness after drying was about 11 μm, dried in an 85 ° C. oven, and dried according to the present invention. A retardation film was obtained. Table 1 shows the optical properties and durability test results of this film.

Comparative Example 1 3.7% by weight of synthetic hectorite (trade name, manufactured by Laponite XLSlaporte), which is a water-swellable inorganic layered compound, and polyvinyl alcohol (trade name, Poval 103)
Kuraray Co., Ltd .: saponification degree 98.5%, polymerization degree 30
0) is coated with an aqueous dispersion containing 4.4% by weight of a triacetyl cellulose film having a thickness of 80 μm (trade name: Fujitack SH)
-80 manufactured by Fuji Photo Film Co., Ltd.) was subjected to surface saponification treatment to obtain an isotropic transparent resin substrate. On this substrate, the layer containing polyvinyl alcohol and the water-swellable inorganic layered compound had a thickness of about dried. The aqueous dispersion was applied using a bar coater so as to have a thickness of 16 μm, and dried in an oven at 100 ° C. to obtain a retardation film in which the in-plane retardation value was smaller than the retardation value in the film thickness direction. Table 1 shows the optical properties and durability test results of this film.

[0036]

[Table 1] Remarks: Humidity and heat resistance ○: No problem occurred up to 500 hours. ×: Peeling occurred between the layer containing the polyvinyl alcohol and the water-swellable inorganic layered compound and the substrate film by 500 hours.

Claims (18)

[Claims] 1. A retardation film having at least one layer containing at least one kind of organoclay composite dispersible in an organic solvent. 2. A film having at least one layer containing at least one kind of organoclay composite dispersible in an organic solvent, wherein the in-plane retardation value is 50 nm or less and the in-film retardation value is thickness. Retardation film smaller than the direction retardation value. 3. A layer comprising at least one kind of organoclay composite dispersible in an organic solvent is formed on at least one surface of a transparent resin substrate, and the retardation value in the film surface is 50 nm or less, and Retardation film having a retardation value smaller than the retardation value in the film thickness direction. 4. The retardation film according to claim 1, wherein the organic clay composite is a compound obtained by compounding a clay mineral having a layered structure with an organic compound. 5. The retardation film according to claim 4, wherein the clay mineral is a smectite group or swellable mica. 6. The retardation film according to claim 5, wherein the smectite group is hectorite, montmorinite or bentonite or a substitute or derivative thereof. 7. The organic compound according to claim 4, wherein the organic compound is an amine compound.
The retardation film according to the above. 8. The amine compound is a quaternary ammonium compound,
The retardation film according to claim 7, wherein the retardation film is urea, hydrazine, or doditerpyridinium. 9. The layer according to claim 1, wherein the layer containing at least one kind of organoclay composite comprises a composition containing at least one kind of organoclay composite and at least one kind of hydrophobic resin. 3. The retardation film according to 3. 10. The retardation film according to claim 9, wherein the composition ratio between the organoclay composite and the hydrophobic resin is in the range of 1: 2 to 10: 1 by weight. 11. The retardation film according to claim 9, wherein the hydrophobic resin is a vinyl resin or a cellulose resin. 12. The retardation film according to claim 9, wherein the hydrophobic resin is polyvinyl butyral. 13. The retardation film according to claim 3, wherein the transparent resin substrate is an isotropic transparent resin substrate. 14. The retardation film according to claim 13, wherein the isotropic transparent resin substrate is a triacetyl cellulose film formed by a solvent casting method. 15. The retardation film according to claim 3, wherein a layer containing at least one kind of organic clay composite is formed on at least one surface of the transparent resin substrate via an anchor coat layer. 16. The retardation film according to claim 3, wherein the layer containing at least one kind of organoclay composite is formed on at least one side of a transparent resin substrate whose surface is corona-treated. 17. The retardation film according to claim 1, wherein the layer containing at least one kind of organoclay composite has a thickness of 1 to 50 μm. 18. A liquid crystal display device comprising at least one retardation film according to claim 1, 2 or 3.