JPH1010320A - Phase-difference film and liquid crystal display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the adhesion of a layer of a compsn. contg. PVA(polyvinyl alcohol) or its deriv. and a water-swellable inorg. laminar compd. to a transparent resin substrate and to improve the durability of a phase-difference film by forming the layer on the substrate with an anchor coat layer in-between. SOLUTION: A layer of a compsn. contg. at least one kind of PVA or its deriv. having a polymn. degree of 200-1,000 and at least one kind of water- swellable inorg. laminar compd. having <=1μm average particle diameter is formed on at least one side of an isotropic transparent resin substrate with an anchor coat layer in-between to obtain the objective phase-difference film having >=80% light transmissivity. Retardation value in the surface of the film is lower than that in the thickness direction of the film and the discoloration of the film after the lapse of 1,000hr in an environment at 80 deg.C corresponds to a color difference ΔE* of <=5 in an L*a*b* color system. The water- swellable inorg. laminar compd. is, e.g. a water-swellable clay mineral and the refractive index in the surface is different from that in the thickness direction.

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 '= (nXY-nz) .multidot.
d (nXY: refractive index in the plane of the film, nz: 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. Can be. 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, the in-plane retardation value (R ₀ ) and the slow axis are set to the tilt axis by, for example, laminating the film to a uniaxially oriented film such as polystyrene having a negative refractive index anisotropy using an adhesive. The ratio (R ₄₀ / R ₀ ) of the retardation value (R ₄₀ ) measured at an inclination of 40 ° can be controlled in the range of 0.9 to 1.1. )
The viewing angle characteristics of the liquid crystal display 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.

[0005] However, a retardation film obtained by forming an aqueous dispersion of polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound on a transparent resin substrate has excellent optical characteristics, but has a poor position between the polarizing plate and the liquid crystal cell. In a wet heat environment in a state in which the retardation film is sandwiched with an adhesive, a durability defect may occur, in which a layer made of polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound is separated from the transparent resin substrate. .

In order to improve the durability, it is effective to enhance the adhesion at the interface between the transparent resin substrate and the layer composed of the polyvinyl alcohol or a derivative thereof and the water-swellable inorganic layered compound. As a method for enhancing the adhesiveness of the interface, a method of introducing an anchor coat layer (primer layer) is generally known. JP-A-5-177782 discloses an additional primer for forming a layer comprising a composition containing an inorganic layered compound and a resin obtained from a crosslinking agent on at least one surface of an opaque or transparent film or sheet substrate. An embodiment of applying a layer to a substrate is also described.

[0007]

However, this primer layer is composed of a water-insoluble polymer, and is not intended to improve the adhesion between the layer containing the inorganic layered compound and the substrate, but to the oxygen barrier which is the object of the patent. This is to make a significant improvement in gender. Further, since the purpose is to obtain a film having excellent oxygen barrier properties, the average particle size of the inorganic layered compound to be used is as large as 10 to 30 μm, and in order to use it as a retardation film, in terms of transparency and the like. Not enough.

As described above, the adhesiveness between the transparent resin substrate and the composition layer containing polyvinyl alcohol or a derivative thereof and the water-swellable inorganic layered compound in a wet heat environment while satisfying the optical properties required for the retardation film. However, an effective method for improving the above, that is, a retardation film having excellent durability has not been found. In view of such a situation, the present inventors have intensively studied a retardation film using polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound. As a result, a composition containing polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound was used. Is formed on at least one side of a transparent resin substrate via an anchor coat layer, whereby a retardation film having excellent durability can be developed, and the present invention has been completed.

[0009]

That is, the present invention is as follows. (1) An isotropic transparent resin substrate comprising a composition containing at least one kind of polyvinyl alcohol having a degree of polymerization of 200 to 1000 or a derivative thereof, and at least one kind of a water-swellable inorganic layered compound having an average particle size of 1 μm or less. A film formed on at least one side via an anchor coat layer, the retardation value in the film plane is smaller than the retardation value in the film thickness direction, the light transmittance is 80% or more, and A retardation film having a color difference ΔE ^* of 5 or less in an L ^* a ^* b ^* color system after 1000 hours in an environment of 80 ° C. (2) A composition containing at least one polyvinyl alcohol having a degree of polymerization of 200 to 1000 or a derivative thereof, and at least one water-swellable inorganic layered compound having an average particle diameter of 1 μm or less has a negative refractive index anisotropy. The film is formed on at least one side of a uniaxially oriented transparent resin substrate made of a thermoplastic resin having an insulating property through an anchor coat layer, and the retardation value in the film plane (R ₀ ) and the slow axis are defined as the tilt axis. The retardation value (R
₄₀ ) is in the range of 0.9 to 1.1 (R ₄₀ / R ₀ ), the light transmittance is 80% or more, and 1 in an environment of 80 ° C.
A retardation film having a color difference ΔE ^* of 5 or less in an L ^* a ^* b ^* color system after a lapse of 000 hours. (3) A liquid crystal display device using at least one retardation film according to (1) or (2).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The water-swellable inorganic layered compound used in the present invention has a layered structure in which unit crystal layers are stacked on top of each other, and the bonding between the unit crystal layers is relatively weak. Clay minerals that can swell between the unit crystal layers until they exhibit their properties, have water swelling properties, and have different in-plane refractive indices and thickness-direction refractive indices.

Among the clay minerals having a water swelling property, the smectite group is preferably used for a retardation film because of its excellent transparency. Examples of the smectite group include montmorillonite and hectorite. Above all, in order to be used for a retardation film, those having few chemically synthesized impurities are preferable in terms of transparency and the like.

For use as a retardation film for a liquid crystal display device, the transmittance of visible light must be 80% or more, preferably 85% or more, and the transparency after film formation is improved. For this purpose, the water-swellable inorganic layered compound preferably has an average particle size of 1 μm or less, and is preferably a synthetic smectite group in which the average particle size is controlled to be smaller than the wavelength of visible light, and particularly preferably a synthetic hectorite.

Examples of the polyvinyl alcohol or derivatives thereof used in the present invention include unmodified polyvinyl alcohol, silanol-modified polyvinyl alcohol, epoxy-modified, acetoacetyl-modified, amino-modified and ammonium-modified polyvinyl alcohol. From the viewpoint of excellent stability of the aqueous dispersion with the water-swellable inorganic layered compound,
Unmodified polyvinyl alcohol having a saponification degree of 70% or more is preferably used. The term "stability of an aqueous dispersion" as used herein means that gelation or cloudiness does not occur for at least several days after preparing an aqueous dispersion of polyvinyl alcohol and a water-swellable inorganic layered compound. Further, the polymerization degree of polyvinyl alcohol or a derivative thereof is preferably from 200 to 1,000, and particularly preferably from 200 to 500 from the viewpoint of excellent stability of the aqueous dispersion.

The composition ratio of the water-swellable inorganic layered compound to polyvinyl alcohol or a derivative thereof is 2: 1 by weight.
It is preferable that the ratio be in the range of from 1:10 to improve mechanical properties such as prevention of cracking of a layer comprising the water-swellable inorganic layered compound and polyvinyl alcohol or a derivative thereof. The aqueous dispersion of the composition mixed in this range has good stability of the liquid, and when formed on a transparent resin substrate, the in-plane retardation value is smaller than the retardation value in the thickness direction. Also exhibit small optical characteristics.

As a dispersion medium for swelling or dispersing the water-swellable inorganic layered compound, water is preferably used, but water / methanol or a water / ethanol mixed solution may be used for the purpose of adjusting the viscosity. In this case, the concentration of methanol or ethanol in the dispersion medium is preferably up to about 20% for the stability of the aqueous dispersion.

As a method for preparing an aqueous dispersion of a composition containing polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound, a method that does not cause gelation or white turbidity for at least several days after the preparation of the aqueous dispersion is used. There is no particular limitation as long as the concentration is high, it is easy to gel, and when the concentration is low, a large number of coatings are required to achieve a thickness that expresses desired optical characteristics when forming a film by a coating method. Therefore, the total solid concentration of polyvinyl alcohol or a derivative thereof and the water-swellable inorganic layered compound is 3 to 15%.
It is preferable to be within the range. Since the optimum solid content concentration depends on the composition ratio of polyvinyl alcohol or a derivative thereof and the water-swellable inorganic layered compound, it is set for each composition ratio.

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 and an STN type liquid crystal display device. The thickness of the layer containing the polyvinyl alcohol or its derivative and the water-swellable inorganic layered compound after film formation is controlled so that the directional retardation value (R ′) is obtained. Depending on the composition ratio of polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound,
Usually, it is set in the range of 1 to 30 μm.

The anchor coat layer used in the present invention is not particularly limited as long as it can enhance the adhesion between the layer composed of the water-swellable inorganic layered compound and polyvinyl alcohol or a derivative thereof and the transparent resin substrate. A water-soluble resin is preferably used from the viewpoint of, for example, the adhesion between the layered inorganic compound and a layer made of polyvinyl alcohol or a derivative thereof. Examples of the water-soluble resin include polyvinyl alcohol or a derivative thereof, a water-soluble cellulose-based resin, a water-soluble acrylamide-based resin, and polyethyleneimine. Among them, polyvinyl alcohol or a derivative thereof is preferably used. Also, a plurality of water-soluble resins can be used in combination. Examples of the polyvinyl alcohol or a derivative thereof used in the anchor coat layer include unmodified polyvinyl alcohol, a silanol-modified polyvinyl alcohol, an epoxy-modified product, an acetoacetyl-modified product, an amino-modified product, and an ammonium-modified product. Saponified polyvinyl alcohol and acetoacetyl-modified polyvinyl alcohol are preferably used.
Further, the polymerization degree is preferably 200 to 2400,
Among them, 1000 to 2000 is more preferable. Hydroxyethyl cellulose as the water-soluble cellulose resin,
Examples thereof include hydroxymethylcellulose and carboxymethylcellulose, and hydroxyethylcellulose is preferred because of its excellent adhesion.

Further, by using a cross-linking agent in combination with these water-soluble resins, the wet heat resistance of the anchor coat layer can be further improved. Examples of the crosslinking agent include an aldehyde compound, an epoxy compound, an amine compound, an aluminum compound, and a phosphoric acid compound. As the aldehyde compound, any water-soluble polyhydric aldehyde can be used, and examples thereof include glyoxal, glutaraldehyde, and urea / glyoxal / acrylamide polycondensate. As the epoxy-based compound, any compounds can be used as long as they are water-soluble, and the epoxy ring is stable and cross-linking reactivity is maintained in an aqueous solution, and sorbitol polyglycidyl ether, glycerol polyglycidyl ether, Examples thereof include polyethylene glycol glycidyl ether and epichlorohydrin.
Examples of the amine compound include ethylene diamine and polyamide resin, examples of the aluminum compound include aluminum sulfate, and examples of the zirconium compound include zirconyl ammonium carbonate. Among these, those which proceed at a relatively low temperature at which thermal deformation of the substrate film does not occur so much are preferable. When a crosslinking agent is used, a catalyst for promoting the crosslinking reaction and other additives can be added.

The amount of the crosslinking agent added to the water-soluble resin is 10
% Or less, and preferably 0.5 to 5%. However, since some cross-linking agents such as aldehyde compounds discolor yellow due to heat, the amount of such a cross-linking agent should be reduced. It is necessary to suppress the discoloration within an allowable range. Further, the thickness of the anchor coat layer is 0.1 to 5
Although it is used in the range of μm, it is necessary to suppress discoloration to an allowable range or less by setting the thickness to 1 μm or less for those discolored by heat. When a retardation film is applied to a liquid crystal display device, usually, one or two retardation films are used. It is necessary that one sheet satisfies the allowable range, but it is more preferable that two sheets satisfies the allowable range. In the present invention, the allowable range of discoloration is L ^*
In the a ^* b ^* color system (JIS Z-8729), the color difference ΔE ^* between the color before the test and the color after 1000 hours in a temperature environment of 80 ° C. is 5 or less.

The concentration of the solid content of the solution for forming the anchor coat is usually 50% or less for adjusting the viscosity of the solution and the like. However, in order to stably form a thin film having a thickness of 0.1 to 5 μm, the solid content is 1%. It is preferable to set in the range of 10% to 10%.

The method for forming a layer containing a polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound and an anchor coat layer on a transparent resin substrate is not particularly limited, but a direct gravure method, a reverse gravure method, Coating methods such as 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. In order to optimize the viscosity characteristics of the liquid with respect to the coating apparatus during film formation, a viscosity modifier such as a thickener is added to the coating liquid, and water containing polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound is added. A method of adjusting the liquid viscosities of the dispersion liquid and the anchor coat liquid can also be used.

An isotropic transparent resin substrate on which a layer containing a polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound is formed via an anchor coat layer has a thickness of 50 to 200 μm having a small orientation and excellent uniformity. The film is not particularly limited as long as it has the following, but a film in which the in-plane retardation value is controlled to 20 nm or less is preferable. Examples of such a film include a cellulose film, a polycarbonate film, a polystyrene film, a polysulfone film, an acrylic film produced by a solvent casting method, and an acrylic film having a low residual stress formed by a precision extrusion method. The surface of these films may be subjected to a physical surface treatment such as a corona treatment or a chemical surface treatment such as a saponification treatment in order to further enhance the adhesion to the anchor coat layer. Among these, a triacetylcellulose film that has been subjected to a surface saponification treatment after being formed by a solvent casting method is preferably used because the in-plane retardation value is small and the uniformity is excellent. When using a surface-saponified triacetylcellulose film, a layer containing polyvinyl alcohol or a derivative thereof and a water-swellable inorganic layered compound is directly formed on the triacetylcellulose film used as a protective film of the polarizing plate. The film may be formed via an anchor coat layer.

Further, a thermoplastic resin having a negative refractive index anisotropy
Combination with uniaxially oriented film made of resin
, The in-plane retardation value (R₀) And late
Retardation measured at 40 degrees with the axis as the tilt axis
Option value (R₄₀) Ratio (R₄₀/ R ₀) Of 0.9-1.1
Can be controlled within the range, and the
The field angle characteristics can be improved. Combination method
As polyvinyl alcohol or its derivatives and water
The layer containing the swellable inorganic layered compound is interposed through the anchor coat layer.
Adhesive on a film formed on an isotropic transparent resin substrate
Thermoplastic resin with negative refractive index anisotropy via
In addition to the method of laminating with a uniaxially oriented film consisting of
Uniaxial arrangement made of thermoplastic resin with negative refractive index anisotropy
Directional film is used as a transparent resin substrate
Nyl alcohol or its derivatives and water-swellable inorganic layering
Method for forming a layer containing a compound via an anchor coat layer
Can be used. Heatable with negative refractive index anisotropy
As a uniaxially oriented film made of plastic resin,
Titanium resin and acrylic resin are used for solvent casting
It can be obtained by uniaxially stretching after forming a film more
However, because of the ease of retardation, polystyrene
It is preferable to use a system resin. With polystyrene resin
Are polystyrene, styrene and acrylonitrile
Polymer, acrylonitrile / butadiene / styrene copolymer
Coalescence and the like can be exemplified.

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 sheet is insufficient as an optical characteristic for improvement, two sheets may be stacked and arranged. In addition, in order to secure the symmetry of the viewing angle characteristic, one upper and lower sheet is disposed between the upper and lower polarizing plates and the liquid crystal cell. Sheets may be arranged.

[0026]

Industrial Applicability According to the present invention, polyvinyl alcohol or a derivative thereof which is excellent in optical properties, does not cause problems such as peeling in a moist heat environment, has little discoloration in a heating environment, and has excellent durability, and water. It is possible to obtain a retardation film in which the in-plane retardation value of the film comprising the layer containing the swellable inorganic layered compound 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.

[0027]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In addition, the measurement and evaluation of the sample were implemented by the following methods. (1) To measure the average particle size of the water-swellable inorganic layered compound,
A Brookhaven ultrafine particle size analyzer BI-90 was used. (2) The light transmittance of the retardation film was measured using a spectrophotometer UV2200 manufactured by Shimadzu Corporation. (3) The in-plane retardation value (R ₀ ) and the retardation value (R ′) in the film thickness direction of the retardation film were measured using a Nikon Corporation polarized light microscope Optiphoto-Pol as a single color having a wavelength of 546 nm. It was measured by light in a conventional manner. (4) The heat-resistant discoloration test was conducted using a C light source manufactured by Minolta Co., Ltd. for a C light source and a hue L ^* a ^* b ^{* in} a two-degree field of view obtained by bonding two retardation films to a glass plate with an adhesive. Using the color difference meter CT-210, the initial L ^{* 0} a ^{* 0} b ^{* 0} and 80
L ^{* 1} a ^{* 1} b ^{* 1} was measured after standing for 1000 hours in an environment of ° C., and evaluated by the value of the color difference ΔE ^* calculated using the following equation. ^{△ E * = [(L *} 1 -L * 0) 2 + (a * 1 -a * 0) 2 + (b * 1
-B ^{* 0} ) ² ] ^1/2 (5) The moisture and heat resistance test was performed on a polarizing plate (SK-1842AP).
7, manufactured by Sumitomo Chemical Co., Ltd.) and a liquid crystal cell, and two sheets of a retardation film were stuck together by using an adhesive, and left for 500 hours in an environment of a temperature of 40 ° C. and a relative humidity of 90%. Then, it was observed whether or not a problem such as separation occurred at the interface between the layer containing the polyvinyl alcohol or its derivative and the water-swellable inorganic layered compound and the transparent resin substrate.

Example 1 Completely saponified polyvinyl alcohol (trade name: Poval 1)
17H Kuraray Co., Ltd .: Degree of saponification 99.6%, degree of polymerization 1
750), 2.5% acetoacetyl-modified polyvinyl alcohol (trade name: Gosefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and an aqueous solution containing 1.5% ethylenediamine as a crosslinking agent. , Thickness 80μm
A surface-saponified triacetylcellulose film (trade name: Fujitac SH-80, manufactured by Fuji Photo Film Co., Ltd.) was used as an isotropic transparent resin substrate (hereinafter referred to as substrate A), and dried on this substrate. About 0.9μm thick
Was applied using a bar coater and dried in an oven at 100 ° C. to form an anchor coat layer.

Next, a synthetic hectorite (trade name: Laponite XLS Lapor) which is a water-swellable inorganic layered compound is used.
3.7% of polyvinyl alcohol (trade name: Poval 103, manufactured by Kuraray Co., Ltd.)
An aqueous dispersion (hereinafter, referred to as dispersion B) containing 4.4% of a saponification degree of 98.5% and a polymerization degree of 300) is prepared, and polyvinyl alcohol and a water-swellable inorganic layered compound are formed on the anchor coat layer. The dispersion B was applied using a bar coater so that the thickness of the containing layer after drying was about 16 μm, and dried in an oven at 100 ° C. to obtain a retardation film according to the present invention.
Table 1 shows the optical properties and durability test results of this film. As shown in Table 1, this film had excellent properties not only in optical properties but also in a durability test.

Example 2 A retardation film was obtained in the same manner as in Example 1 except that the concentration of ethylenediamine in the anchor coating solution used in Example 1 was 0.75%. Table 1 shows the optical properties and durability test results of this film. As shown in Table 1, this film had excellent properties not only in optical properties but also in a durability test.

Example 3 The concentration of ethylenediamine in the anchor coat solution used in Example 1 was 2.0%, and the thickness of the anchor coat layer was about 0.5%.
A retardation film was obtained in the same manner as in Example 1, except that the thickness after drying of the layer containing polyvinyl alcohol and the water-swellable inorganic layered compound was 8 μm, and the thickness after drying was about 15 μm.
Table 1 shows the optical properties and durability test results of this film. As shown in Table 1, this film had excellent properties not only in optical properties but also in a durability test.

Example 4 The thickness of the anchor coat layer used in Example 1 was about 1.0 μm.
m, a retardation film was obtained in the same manner as in Example 1 except that the thickness of the layer containing the polyvinyl alcohol and the water-swellable inorganic layered compound was about 6 μm after drying. Table 1 shows the optical properties and durability test results of this film.
As shown in Table 1, this film had excellent properties not only in optical properties but also in a durability test.

Example 5 Completely saponified polyvinyl alcohol (trade name: Poval 1)
17H Kuraray Co., Ltd .: Degree of saponification 99.6%, degree of polymerization 1
750), 2.5% acetoacetyl-modified polyvinyl alcohol (trade name: Gosefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 1.5% glyoxal as a cross-linking agent, and chloride as a catalyst. Add zinc to 0.
An aqueous solution containing 2% is dried on the substrate A to a thickness of about 0.5
μm using a comma coater and apply 100
It dried at ° C and formed the anchor coat layer. Next, the dispersion B was applied using a comma coater on the anchor coat layer such that the layer containing the polyvinyl alcohol and the water-swellable inorganic layered compound had a thickness of about 15 μm after drying.
By drying at 00 ° C., a retardation film was obtained. Table 1 shows the optical properties and durability test results of this film.
As shown in Table 1, this film had excellent properties not only in optical properties but also in a durability test.

Example 6 Completely saponified polyvinyl alcohol (trade name: Poval 1)
17H Kuraray Co., Ltd .: Degree of saponification 99.6%, degree of polymerization 1
750), 1.5% acetoacetyl-modified polyvinyl alcohol (trade name: Gosefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 1.5% glyoxal as a crosslinking agent, and chloride as a catalyst. Add zinc to 0.
An aqueous solution containing 2% is dried on the substrate A to a thickness of about 1.0.
μm using a comma coater and apply 100
It dried at ° C and formed the anchor coat layer. Next, the dispersion B is applied using a comma coater on the anchor coat layer so that the layer containing the polyvinyl alcohol and the water-swellable inorganic layered compound has a thickness of about 6 μm after drying.
Drying at 0 ° C. yielded a retardation film. Table 1 shows the optical properties and durability test results of this film. As shown in Table 1, this film had excellent properties not only in optical properties but also in a durability test.

Example 7 Hydroxyethylcellulose (trade name: HEC Daicel SP-400, manufactured by Daicel Chemical Industries, Ltd.) 3.0
% Aqueous solution was applied on a substrate A using a bar coater so that the film thickness after drying was about 1.0 μm, and dried in an oven at 80 ° C. to form an anchor coat layer. Next, the dispersion B was applied using a bar coater on the anchor coat layer such that the layer containing the polyvinyl alcohol and the water-swellable inorganic layered compound had a thickness of about 10 μm after drying, and
Drying at 0 ° C. yielded a retardation film. Table 1 shows the optical properties and durability test results of this film. As shown in Table 1, this film had excellent properties not only in optical properties but also in a durability test.

Example 8 Completely saponified polyvinyl alcohol (trade name: Poval 1)
17H Kuraray Co., Ltd .: Degree of saponification 99.6%, degree of polymerization 1
750), 2.5% acetoacetyl-modified polyvinyl alcohol (trade name: Gosefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and 1.5% aluminum sulfate. Using a bar coater to apply a film thickness of about 0.8 μm after drying,
It was dried in a 00 ° C. oven to form an anchor coat layer. Next, the dispersion liquid B is applied using a bar coater on the anchor coat layer so that the layer after drying of the layer containing polyvinyl alcohol and the water-swellable inorganic layered compound becomes about 18 μm, and dried at 100 ° C. Thus, a retardation film was obtained. Table 1 shows the optical properties and durability test results of this film. As shown in Table 1, this film had excellent characteristics in a durability test.

Example 9 Completely saponified polyvinyl alcohol (trade name: Poval 1)
17H Kuraray Co., Ltd .: Degree of saponification 99.6%, degree of polymerization 1
750) 3.0%, acetoacetyl-modified polyvinyl alcohol (trade name Gosefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 2.0%, polyamide resin (trade name Sumireze Resin 5001 Sumitomo Chemical Co., Ltd.) Co., Ltd.) is applied on a substrate A using a bar coater so that the film thickness after drying is about 1.1 μm, and dried in a 100 ° C. oven to form an anchor coat layer. Formed. Next, the dispersion liquid B is applied using a bar coater on the anchor coat layer such that the layer containing the polyvinyl alcohol and the water-swellable inorganic layered compound has a thickness of about 3 μm after drying, and dried at 100 ° C. Thus, a retardation film was obtained. Table 1 shows the optical properties and durability test results of this film. As shown in Table 1, this film had excellent characteristics in a durability test.

Example 10 Special reactive resin (trade name: Sumireze Resin 5004)
Sumitomo Chemical Co., Ltd .: 45% solids, thickener (Sumifloc FN-12, Sumitomo Chemical Co., Ltd.)
) And 0.2% of sodium hydroxide as a pH adjuster were applied to the substrate A using a bar coater so that the film thickness after drying was about 1.2 μm. 1
It was dried in a 00 ° C. oven to form an anchor coat layer. Next, the dispersion liquid B is applied using a bar coater on the anchor coat layer such that the layer containing the polyvinyl alcohol and the water-swellable inorganic layered compound has a thickness of about 8 μm after drying, and dried at 100 ° C. Thus, a retardation film was obtained. Table 1 shows the optical properties and durability test results of this film. As shown in Table 1, this film had excellent characteristics in a durability test.

Example 11 A 5% aqueous solution of silanol-modified polyvinyl alcohol (trade name: Poval R1130, manufactured by Kuraray Co., Ltd.) was
The resultant was coated with a bar coater so as to have a thickness of about 1.0 μm after drying, and dried in an oven at 120 ° C. to form an anchor coat layer. Next, the dispersion B was coated on the anchor coat layer such that the layer containing the polyvinyl alcohol and the water-swellable inorganic layered compound had a thickness of about 16 μm after drying.
Was applied using a bar coater and dried at 100 ° C. to obtain a retardation film. Table 1 shows the optical properties and durability test results of this film. As shown in Table 1, this film had excellent characteristics in a durability test.

Example 12 Completely saponified polyvinyl alcohol (trade name: Poval 1)
17H Kuraray Co., Ltd .: Degree of saponification 99.6%, degree of polymerization 1
750) and polyethylene imine (trade name: Epomin P-1000, manufactured by Nippon Shokubai) 0.5%,
Epoxy compound (trade name Denacol EX-810)
0.5% by Nagase Kasei Co., Ltd .; Zn (B
An aqueous solution containing 0.25% of F ₄ ) ₂ was applied to the substrate A using a bar coater so that the film thickness after drying was about 1.0 μm, and dried in an oven at 120 ° C. to form an anchor coat layer. Formed. Next, the dispersion liquid B is applied using a bar coater on the anchor coat layer such that the layer after drying of the layer containing polyvinyl alcohol and the water-swellable inorganic layered compound is about 16 μm, and dried at 100 ° C. Thus, a retardation film was obtained. Table 1 shows the optical properties and durability test results of this film. As shown in Table 1, this film had excellent characteristics in a durability test.

Comparative Example 1 Dispersion B was applied to a substrate containing a polyvinyl alcohol and a water-swellable inorganic layered compound using a comma coater so that the thickness after drying was about 16 μm, without providing an anchor coat layer on substrate A. And dried at 100 ° C. to obtain a retardation film. Table 1 shows the optical properties and durability test results of this film. As shown in Table 1, although the film showed little discoloration in the durability test, the adhesion between the layer containing polyvinyl alcohol and the water-swellable inorganic layered compound and the transparent resin substrate was poor.

[0042]

[Table 1] [Moisture and heat resistance] 不 具 合: No trouble 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 (15)

[Claims] 1. The method according to claim 1, wherein at least one of the polymerization degrees is from 200 to 10.
A composition comprising a water-swellable inorganic layered compound having a mean particle diameter of at least 1 μm or less and a polyvinyl alcohol or its derivative of No. 00 is formed on at least one side of an isotropic transparent resin substrate via an anchor coat layer. The retardation value in the film plane is smaller than the retardation value in the film thickness direction,
A retardation film having a light transmittance of 80% or more and a color difference ΔE ^* of 5 or less in an L ^* a ^* b ^* color system after 1000 hours in an environment of 80 ° C. 2. The retardation film according to claim 1, wherein the composition ratio of polyvinyl alcohol or a derivative thereof and the water-swellable inorganic layered compound in the composition is in the range of 1: 2 to 10: 1 by weight. 3. The polyvinyl alcohol derivative is a silanol modified product of polyvinyl alcohol, an epoxy modified product,
The retardation film according to claim 1, which is an acetoacetyl-modified product, an amino-modified product or an ammonium-modified product. 4. The retardation film according to claim 1, wherein the polyvinyl alcohol is a completely saponified product. 5. The retardation film according to claim 1, wherein the water-swellable inorganic layered compound is a synthetic hectorite. 6. The retardation film according to claim 1, wherein the anchor coat layer comprises a water-soluble resin. 7. The retardation film according to claim 1, wherein the anchor coat layer comprises a composition containing a water-soluble resin and a crosslinking agent. 8. The retardation film according to claim 6, wherein the water-soluble resin comprises at least one kind of polyvinyl alcohol having a degree of polymerization of 200 to 2,400 or a derivative of polyvinyl alcohol. 9. The retardation film according to claim 6, wherein the water-soluble resin is a water-soluble cellulose resin. 10. The retardation film according to claim 7, wherein the crosslinking agent is an aldehyde compound, an epoxy compound, an amine compound, an aluminum compound or a zirconium compound. 11. The retardation film according to claim 1, wherein the isotropic transparent resin substrate is a triacetyl cellulose film that has been subjected to a surface saponification treatment after being formed by a solvent casting method. 12. The method according to claim 1, wherein the at least one polymerization degree is from 200 to 10.
A composition comprising a water-swellable inorganic layered compound having a polyvinyl alcohol or its derivative of at least 00 and an average particle diameter of at least 1 μm or less is made of a thermoplastic resin having a negative refractive index anisotropy. A film formed on at least one side of a transparent resin substrate via an anchor coat layer, and a retardation value (R ₀ ) in the film surface and a retardation value (R ₀ ) measured at an inclination of 40 ° with the slow axis as an inclination axis. ₄₀ ), the ratio (R ₄₀ / R ₀ ) is in the range of 0.9 to 1.1, and the light transmittance is 80% or more;
Discoloration after 1000 hours in an environment of ° C. is L ^* a ^*
b ^{* A} retardation film having a color difference ΔE ^* of 5 or less in a color system. 13. A uniaxially oriented transparent resin substrate made of a thermoplastic resin having a negative refractive index anisotropy is a film made of polystyrene or a polystyrene derivative that is formed by a solvent casting method and then uniaxially stretched. Claim 12
The retardation film according to the above. 14. The method according to claim 1, wherein the at least one polymerization degree is from 200 to 10.
Of a composition comprising a water-swellable inorganic layered compound having a mean particle diameter of at most 1 μm or less, and having a thickness of from 1 to 30.
13. The retardation film according to claim 1, wherein the thickness is μm. 15. A liquid crystal display device using at least one retardation film according to claim 1 or 12.