JP2003315551A - Polarizing plate and image display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate in which adhesion failure or decrease in the polarization degree occurring with time or with time at high temperature is reduced. <P>SOLUTION: The polarizing plate has a polarizing film, an oriented film having the retardation of ≥105 nm and ≤300 nm on one surface of the polarizing film, and a saturated norbornene film on the other surface of the polarizing film. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polarizing plate used in an image display device such as a liquid crystal display device, and an image display device using the same.

[0002]

2. Description of the Related Art A liquid crystal display device is generally composed of a liquid crystal cell, a polarizing plate, a reflector or a backlight. In the case of a normal TN type liquid crystal, the polarizing plates are arranged on both sides of the liquid crystal cell. Polarizing plates are used to make incident light orthogonal to each other.
It has a function of dividing into two polarized components, allowing only one of them to pass, and absorbing or dispersing the other components. For example,
In the case of TN type liquid crystal, if the absorption axes of two polarizing films are combined in orthogonal or parallel positions and a twisted and aligned liquid crystal cell is sandwiched between them, transmission or non-transmission of light is switched depending on the presence or absence of an applied voltage. Then, the pattern is displayed by the density ratio of transmitted light in the orthogonal position and the parallel position. Therefore, a polarizing film having a higher degree of polarization and higher transmittance has better performance.

As the polarizing plate, a thin polarizing film is used, and in order to secure durability and mechanical strength, protective layers made of various films are laminated on both sides thereof with an adhesive. In most recent liquid crystal display devices, a polarizing film in which a transparent polymer film is molecularly aligned in a certain direction and a dichroic substance is adsorbed in a gap between micelles is used. Typical examples of such a polarizing film include polyvinyl alcohol (hereinafter abbreviated as PVA) / iodine type, PVA / dye type, PV
A. A PVC type polarizing film such as a polyvinylene type or a polyene type polarizing film may be used. Since many of these polarizing films have low mechanical strength, and are easily contracted by heat or moisture, or the polarizing function is easily deteriorated, a protective layer is usually provided on both sides of the polarizing film. This protective layer has no birefringence, high transmittance, good heat and moisture absorption resistance, high mechanical strength, low shrinkage due to changes in temperature and humidity, and smooth surface. Therefore, performance such as high resolution, good adhesion with an adhesive, and excellent appearance is required. Conventionally, a solution cast film of cellulose triacetate (TAC), which has low birefringence and good appearance, has been mainly used as a protective layer of a polarizing film.

However, the TAC film has a high water vapor permeability, and a polarizing plate having the TAC film as a protective layer has poor durability at high temperature and high humidity. As a method for solving this, Japanese Patent Laid-Open No. 2001-324616 proposes a polarizing plate in which a saturated norbornene-based film having high moisture resistance is bonded as a protective film on both sides of a polarizing film. However, when this polarizing plate was actually used for a liquid crystal display device,
It has been found that poor adhesion and display unevenness appear during long-term aging and high-temperature aging, and improvements have been desired.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a polarizing plate in which the adhesion failure and the decrease in the degree of polarization that occur during long-term aging and high-temperature aging are reduced. Is an issue. Another object of the present invention is to provide a polarizing plate capable of reducing display unevenness caused by the polarizing plate due to long-term aging or high temperature aging when applied to an image display device, particularly a liquid crystal display device. Further, it is an object of the present invention to provide an image display device in which display unevenness caused by a polarizing plate due to long-term aging or high temperature aging is reduced.

[0006]

Means for Solving the Problems As a result of extensive studies, the present invention has revealed that a polarizing film produced by stretching a PVA film or the like shows a large shrinkage stress in the stretching direction due to high temperature aging and long term aging. It was revealed that this was the cause of poor adhesion and a decrease in the degree of polarization that occurred during long-term aging and high-temperature aging. This shrinkage stress is caused by trying to recover the residual strain. As a result of further studies based on this finding, the adhesion failure and the decrease in the polarization degree that occur during long-term aging and high-temperature aging, a stretched film and a saturated norbornene-based resin film having a predetermined retardation, the polarizing film The present invention has been completed by finding that it can be reduced by sandwiching.

Means for solving the above problems are as follows. (1) A polarizing plate comprising a polarizing film, a stretched film having a retardation of 105 nm or more and 300 nm or less on one surface of the polarizing film, and a saturated norbornene-based film on the other surface of the polarizing film. (2) The polarizing plate according to (1), wherein the stretched film is a cellulose acetate film stretched at least uniaxially. (3) The polarizing plate according to (1) or (2), in which the polarizing film, the stretched film, and the saturated norbornene-based resin film are directly laminated. (4) The polarizing plate according to any one of (1) to (3), wherein an angle formed by the stretching axis of the stretched film and the transmission axis of the polarizing film is substantially 45 °.

(5) Wavelength of the stretched film is 550 nm
Has a retardation value (Re550) of 105
nm <Re550 ≦ 330 nm and a wavelength of 450 n
The ratios of retardation values Re450, Re550 and Re650 measured at m, 550 nm and 650 nm satisfy the relations of 0.5 <Re450 / Re550 <0.98 and 1.01 <Re650 / Re550 <1.35, respectively ( The polarizing plate according to 1) to 4). (6) Refractive index n of the stretched film in the in-plane stretching axis direction
where x, refractive index ny in the direction perpendicular to the in-plane stretching axis and refractive index nz in the thickness direction, NZ value = (nx-nz)
/ (Nx-ny) is more than 1.1 and 3 or less, The polarizing plate of (1)-(5) characterized by the above-mentioned.

(7) When the width of the film before stretching is W and the distance between stretchings is L, the stretched flume has 0.3 ≦ L.
/ W ≦ 2, the polarizing plate according to any one of (1) to (6). (8) The polarizing plate according to any one of (1) to (7), wherein the stretched film is stretched at a water content of 2% or more and 10% or less and a stretching ratio of 1.1 times or more and 2 times or less. (9) The stretched film has an acetylation degree of 57.0 to 62.5.
%, And 0.01 to 10 parts by mass of an aromatic compound having at least two aromatic rings with respect to 100 parts by mass of the cellulose acetate. (1) to (8) Polarizer. (10) The polarizing plate according to any one of (1) to (9), wherein the polarizing film has a transmission axis in a direction forming 45 ° with respect to a longitudinal direction (MD). (11) The polarizing plate according to any one of (1) to (10), which is a circularly polarizing plate.

(12) An image display device equipped with the polarizing plate according to any one of (1) to (11). (13) The image display device according to (12), which is a liquid crystal display device. (14) The image display device according to (12), which is a reflective liquid crystal display device. (15) A touch panel using the polarizing plate according to any one of (1) to (11).

In the present invention, a PVA film or the like stretched to impart polarization characteristics is referred to as a "polarizing film", and a film obtained by laminating at least one film is referred to as a "polarizing plate". To distinguish. Unless otherwise specified, the retardation means the retardation at a wavelength of 550 nm.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. The polarizing plate of the present invention has a polarizing film, a stretched film on one surface of the polarizing film, and a saturated norbornene-based resin film on the other surface of the polarizing film. In the present invention, by sandwiching the polarizing film between the stretched film and the saturated norbornene-based film, the shrinkage stress of the polarizing film that develops during long-term aging and high temperature aging is relaxed, and adhesion failure and the resulting adhesion failure and It reduces the decrease in the degree of polarization. Retardation can be used as a measure of whether or not the stretched film is stretched to such an extent that the shrinkage stress of the polarizing film can be relaxed. In the present invention,
The stretched film has a retardation of 105 nm or more and 300 nm or less, more preferably 115 nm or more and 200 nm or less, and further preferably 125 nm.
It is 180 nm or less.

A preferred embodiment of the polarizing plate of the present invention is a polarizing plate having a stretched film of a cellulose acetate film as the stretched film. A polarizing plate is generally manufactured by applying an adhesive or the like dissolved in a solvent on both surfaces of a polarizing film, sandwiching the film with a film, and then drying the film. If a film with high moisture resistance (for example, a film of saturated norbornene-based resin) is used on both sides of the polarizing film for the purpose of improving resistance to high humidity, it will not be possible to dry sufficiently during drying, resulting in poor adhesion. Easy to develop. As in this embodiment, a saturated norbornene film is formed on one surface of the polarizing film,
By laminating a small moisture-proof cellulose acetate film on the other surface, the solvent during drying easily volatilizes,
The adhesion is further improved.

The polarizing plate of the present embodiment may include a film other than the saturated norbornene-based resin film and the stretched film, and examples thereof include those having the following laminated structure. Among them, the laminated structure A is preferable. That is, a structure in which a saturated norbornene-based film and a stretched cellulose acetate film are directly laminated on the polarizing film is preferable. Thereby, the shrinkage stress of the polarizing film,
It can be directly transferred to the stretched film, is highly efficient, and avoids complication of the process and reduction of light transmittance due to an increase in the number of layers.

Laminated Structure A: Saturated Norbornene Film / Polarizing Film / Stretched Cellulose Acetate Film Laminated Structure B: Saturated Norbornene Film / Polarizing Film / Unstretched Cellulose Acetate Film / Stretched Cellulose Acetate Film Laminated Structure C: Saturated Norbornene Film / Unstretched cellulose acetate film / polarizing film / stretched cellulose acetate film laminated structure D: unstretched cellulose acetate film / saturated norbornene film / polarized film / stretched cellulose acetate film laminated structure E: saturated norbornene film / polarized film / stretched cellulose acetate Film / unstretched cellulose acetate film laminated structure F: saturated norbornene film / polarizing film / stretched cellulose acetate film / saturated norbornene film product Structure G: Saturated norbornene film / stretched cellulose acetate film / polarizing film / stretched cellulose acetate film laminated structure H: Stretched cellulose acetate film / saturated norbornene film / polarized film / stretched cellulose acetate film laminated structure I: Saturated norbornene based film / Stretched cellulose acetate film / polarizing film / stretched cellulose acetate film laminated structure J: saturated norbornene film / polarizing film / saturated norbornene film / stretched cellulose acetate film

Another preferred embodiment of the polarizing plate of the present invention is a polarizing plate in which the angle between the stretching axis of the stretched film and the transmission axis of the polarizing film is substantially 45 °.
The polarizing film is usually produced by stretching a PVA-based film or the like, and this PVA-based film exhibits a large shrinkage stress at high temperature. This is due to trying to recover the residual strain. In order to counter this stress, it is preferable to combine a film having a contraction stress in a direction different from the stretching direction (transmission axis direction) of the polarizing film. Usually, the stretched polymer film tends to shrink at a high temperature, so that a large shrinkage stress appears in the stretching direction. Therefore, it is preferable that the stretching direction of the stretched film and the absorption axis of the polarizing film are orthogonal to each other. That is, the expansion in the orthogonal direction (TD), which appears as a reaction of the contraction of the polarizing film,
This is because it can be suppressed by the shrinkage of the stretched film. On the other hand, the stretched film has the highest elastic modulus in the stretching direction. Therefore, it is possible to more effectively resist the contraction stress of the polarizing film by making the stretching direction of the stretched film and the absorption axis of the polarizing film parallel to each other. In the present embodiment, the stretched films are laminated at an angle of 45 ° with respect to the transmission axis of the polarizing film, so that the stretching axes are arranged orthogonally and parallel to the transmission axis. We are getting the benefits of both.

Hereinafter, materials usable for the polarizing film, the saturated norbornene-based resin film, and the stretched film used in the present invention, and production examples of each film are described. (Polarizing Film) The polarizing film that can be used in the polarizing plate of the present invention is not particularly limited, and any of an iodine-based polarizing film, a dye-based polarizing film using a dichroic dye, a polyene-based polarizing film, and the like can be used. You can Above all, an iodine-based polarizing film and a dye-based polarizing film made of a polyvinyl alcohol-based film are preferable. In the present invention, it is preferable to use a polarizing film having a transmission axis of 45 degrees with respect to the longitudinal direction (MD). The polarizing film
When a film having an absorption axis at 45 ° with respect to the longitudinal direction (MD) is used, the stretched film and the polarizing film are laminated by roll-to-roll, and the stretching axis of the stretched film and the polarizing film of the preferred embodiment described above are used. The angle formed by the transmission axis is substantially 45
A polarizing plate having an angle of ° can be easily manufactured. That is,
When the polarizing plate is prepared using a polarizing film and a stretched film stretched in the longitudinal direction, it is necessary to cut out the polarizing film or the stretched film from the roll once and then stack them by shifting them by 45 °, which complicates the operation. It is in. On the other hand, when a polarizing film having a transmission axis of 45 degrees with respect to the longitudinal direction (MD) as described above is used, the stretched film and the polarizing film are bonded by roll-to-roll as described above, and easily produced. can do. Such a polarizing film is disclosed in JP 2001-3
It can be produced according to the methods described in JP-A-43525 and JP-A-2002-48918.

The polarizing film having a transmission axis of 45 degrees with respect to the longitudinal direction (MD) can be specifically manufactured by the following method. A locus L1 of the holding means from the substantial holding start point at one end to the substantial holding release point and a locus L2 of the holding means from the substantial holding start point at the other end of the polarizing film to the substantial holding release point. And the distance W between the two substantial holding release points satisfies the following formula (A), maintains the supportability of the polarizing film, and shrinks after stretching in the state where the volatile content is 5% or more. It can be manufactured by lowering the volatile content while performing the process. Formula (A) | L2-L1 |> 0.4W

FIG. 1 shows a schematic plan view of an apparatus for producing a polarizing film whose orientation is inclined at 45 ° by oblique stretching. (A)
Is the process of introducing the original film in the direction of arrow (a),
(B) is a width direction stretching step, and (c) is a step of feeding the stretched film to the next step in the (c) direction. The film is continuously introduced from the direction (a), and is first held by the holding means on the left side as viewed from the upstream side at point B1. At this point, one film edge is not held yet, and no tension is generated in the width direction. That is, the point B1 does not correspond to the actual holding start point. The substantial holding start point is defined as the point where both ends of the film are held for the first time, and this is the holding start point A1 on the more downstream side,
A straight line drawn from A1 substantially perpendicularly to the center line 21 of the introduction side film is indicated by two points C1 intersecting with the trajectory 23 of the holding means on the opposite side. Starting from this point, when the holding means at both ends is conveyed at substantially the same speed, A1 becomes A per unit time.
2, A3 ... An, C1 is C2, C3 ... C
Move to n. That is, the straight line connecting the points An and Cn through which the holding means serving as the reference passes at the same point is the stretching direction at that time. Since An gradually lags behind Cn as shown in FIG. 2, the stretching direction gradually inclines from the direction perpendicular to the transport direction. The substantial holding release point is a Cx point that is separated from the holding means at a more upstream position, and a straight line drawn substantially perpendicular to the center line 22 of the film sent from Cx to the next step is the trajectory 14 or 24 of the holding means on the opposite side. It is defined by two intersecting points Ay. The final angle of the stretching direction is the stroke difference Ay-Ax (that is, | L) of the left and right holding means at the end point of the substantial stretching process.
1-L2 |) and the actual exit width Ay-Cx (ie W)
It depends on the ratio of. Here, the inclination angle θ formed by the stretching direction with respect to the conveying direction to the next step is represented by tan θ = (Ay−Cx) / (Ay−Ax), that is, tan θ = | L1-L2 | / W. The film edge on the upper side of the drawing is held up to 28 even after the Ay point, but since the other end is not held, new widthwise stretching does not occur, and 28 is not a substantial holding release point.

As described above, the substantial holding start point is not a simple biting point into each of the left and right holding means, but the biting point on the further downstream side is one point, and the one point is the right and left substantial holding start points. The connecting straight line is defined as being substantially orthogonal to the center line of the film introduced into the holding process.
Similarly, with the substantial holding release point, the departure point on the upstream side is taken as one point, and now the point is a straight line connecting the left and right substantial holding release points.
It is defined as being substantially orthogonal to the center line of the film sent to the next step. The term “substantially orthogonal” means that the straight line connecting the center line of the film and the left and right substantial holding starting points or substantial holding releasing points is 90 ± 0.5 °.

When an attempt is made to make a difference in the left and right strokes using a tenter type stretching machine, due to mechanical restrictions such as rail length, the position often held for the first time by the left and right holding means when viewed from the introduction side or the next process side. As seen from the above, there is a front-back difference in the position of separation from the left and right holding means.
If the relationship of is satisfied, an arbitrary front-back difference can be added.

In the above, the inclination angle of the orientation axis in the obtained stretched film can be controlled and adjusted by the ratio of the outlet width W in the step (c) and the stroke difference | L1-L2 | of the substantially left and right holding means. it can. For polarizing plates and retardation films, a film oriented at 45 ° with respect to the longitudinal direction is often required. To obtain an orientation angle close to 45 °, 0.9W <
| L1-L2 | <1.1 W is desirable, and 0.
More preferably, 97W <| L1-L2 | <1.03W.

The thickness of the polarizing film is preferably 5 μm to 60 μm, more preferably 10 μm to 40 μm, and 12 μm.
˜30 μm is more preferable.

(Saturated norbornene-based resin film) As the saturated norbornene-based resin film usable in the present invention, for example, (1) a ring-opening (co) polymer of a norbornene-based monomer is added with maleic acid, if necessary, After polymer modification such as cyclopentadiene addition,
Examples of the film include a hydrogenated resin, (2) a resin obtained by addition-type polymerization of a norbornene-based monomer, and (3) a resin obtained by addition-type copolymerization of a norbornene-based monomer with an olefin-based monomer such as ethylene or α-olefin. To be Polymerization and hydrogenation of the saturated norbornene-based monomer can be performed by a conventional method.

Examples of the norbornene-based monomer include norbornene and its alkyl- and / or alkylidene-substituted compounds such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-Butyl-2-norbornene, 5-ethylidene-2-norbornene, etc., and their polar substituents such as halogen; dicyclopentadiene, 2,
3-dihydrodicyclopentadiene, etc .; dimethanooctahydronaphthalene, its alkyl and / or alkylidene substituents, and polar group substituents such as halogen, for example, 6-methyl-1,4: 5,8-dimethano-1, 4,
4a, 5,6,7,8,8a-octahydronaphthalene, 6-ethyl-1,4: 5,8-dimethano-1,4,4
4a, 5,6,7,8,8a-octahydronaphthalene, 6-ethylidene-1,4: 5,8-dimethano-1,
4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: 5,8-dimethano-1,
4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4: 5,8-dimethano-1,
4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-pyridyl-1,4: 5,8-dimethano-1,
4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octa Hydronaphthalene and the like; Addition products of cyclopentadiene and tetrahydroindene and the like; Cyclopentadiene trimer and tetramer, for example, 4,9: 5,8-dimethano-3a, 4,4
a, 5,8,8a, 9,9a-octahydro-1H-benzoindene, 4,11: 5,10: 6,9-trimethano-3a, 4,4a, 5,5a, 6,9,9a, 10 ，
10a, 11,11a-dodecahydro-1H-cyclopentaanthracene; and the like.

Other cycloolefins capable of ring-opening polymerization can be used in combination with the norbornene-based monomer within the range not impairing the object of the present invention. Specific examples of such a cycloolefin include, for example,
One reactive double bond such as cyclopentene, cyclooctene, 5,6-dihydrodicyclopentadiene
Examples thereof include compounds having individual groups. The saturated norbornene-based resin used in the present invention has a number average molecular weight of usually 25,000 to 100,000, preferably 30,000 to 80,000 as measured by a gel permeation chromatograph (GPC) method using a toluene solvent. , And more preferably 3
It is in the range of 5,000 to 70,000. If the number average molecular weight is too small, the physical strength will be poor, and if it is too large, the operability during molding will be poor. The glass transition temperature (Tg) of the saturated norbornene type resin is 100 ° C to 25 ° C.
The temperature is preferably 0 ° C., more preferably 115 ° C. to 220 ° C., further preferably 130 ° C. to 200 ° C.

When a hydrogenated product of a ring-opening polymer of a norbornene-based monomer is used as the thermoplastic saturated norbornene-based resin, the hydrogenation rate is usually 90% or more from the viewpoint of heat deterioration resistance and light deterioration resistance. Preferably 95
% Or more, more preferably 99% or more. The thermoplastic saturated norbornene-based resin is excellent in transparency, heat resistance, moisture resistance, physical strength, adhesiveness with an adhesive, durability against an adhesive, and the like. A sheet having a thickness of 25 μm, a hygroscopic property of usually 0.05% or less, preferably 0.01% or less, a water vapor permeability of 25 ° C., and an environment of 90% relative humidity, 20 g / m ²
-The thing of 24 hours or less can be easily obtained. Also, because its photoelastic coefficient is small, external force is applied,
Even if there is residual stress, the effect on retardation is small, and it is suitable for producing an optically uniform film. The photoelastic coefficient thereof is preferably 3 to 9 × 10 ^-13 cm ² / dyne.

If desired, the thermoplastic saturated norbornene-based resin used in the present invention may be added with various additives such as phenol-based and phosphorus-based antioxidants, antistatic agents, and ultraviolet absorbers. In particular, since liquid crystals are usually deteriorated by ultraviolet rays, it is preferable to add an ultraviolet absorber when other protective means such as laminating an ultraviolet protective filter is not taken. As the UV absorber, a benzophenone-based UV absorber, a benzotriazole-based UV absorber, an acrylonitrile-based UV absorber, or the like can be used. Among them, the benzophenone-based UV absorber is preferable, and the addition amount is usually 10 ~ 100,000 pp
m, preferably 100 to 10,000 ppm. Further, when a sheet is produced by a solution casting method, it is preferable to add a leveling agent in order to reduce the surface roughness.
As the leveling agent, for example, a fluorine-based nonionic surfactant, a special acrylic resin-based leveling agent, a coating leveling agent such as a silicone-based leveling agent can be used, and among them, those having good compatibility with a solvent are preferable, The addition amount is usually 5 to 50,000 ppm, preferably 10 to 20,000 ppm.

The saturated norbornene-based resin film that can be used in the present invention comprises the above saturated norbornene-based resin,
It is formed into a film. As a film forming method,
The solution casting method and the melt film forming method are preferable.

First, an example of producing a saturated norbornene resin by the solution casting method will be described. In the solution casting method, the saturated norbornene-based resin is dissolved in a solvent to prepare a resin solution. The solvent has a solid content concentration of 10 at 25 ° C.
A solvent that can be uniformly dissolved in not less than mass% is preferable. Examples of such a solvent include toluene, xylene, ethylbenzene, chlorobenzene, trimethylbenzene, diethylbenzene, isopropylbenzene, chlorobenzene and the like, and among them, xylene, ethylbenzene, chlorobenzene, dichloromethane and dioxolane are preferable. Further, these solvents may contain cyclohexane, chloroform, benzene, cyclic ethers such as tetrahydrofuran and dioxane, or linear hydrocarbons such as n-hexane and n-octane. Those which satisfy these conditions satisfactorily include those containing 50% or more of an aromatic solvent such as xylene and ethylbenzene, dichloromethane and dioxolane.

The resin concentration in the resin solution is usually 5 to 6
It is 0% by mass, preferably 10 to 50% by mass, more preferably 20 to 45% by mass. If the concentration of the resin is too low, it is difficult to adjust the thickness of the sheet because the viscosity is low, and if the concentration is too high, the viscosity is high and the film-forming property is poor, and a film having good appearance cannot be obtained.

The conditions and the like for casting the resin solution are not particularly limited, and the conditions for the usual solution casting method can be referred to. Specifically, the resin solution is applied with a bar coater, a T-die, a T-die with a bar, a doctor knife, a meer bar,
Using roll coat, die coat, etc., heat resistant materials such as polyethylene terephthalate, steel belts,
It can be cast on a flat plate such as a metal foil or a roll to form a film. After that, it is preferable that the casting film is dried to a residual solvent concentration of 2% by mass or less. If the residual solvent concentration is too high, the heat resistance is poor, and when used in a high temperature environment, the residual solvent evaporates, which adversely affects the surroundings and causes deformation.

In order to reduce the amount of residual solvent in the film to 2% by mass or less, it is usually preferable to carry out drying in two stages. First, in the first drying step, the casting film is dried by heating it on a flat plate or a roll in a temperature range of 30 to 100 ° C, preferably 40 to 80 ° C, and the residual solvent concentration is 10% by mass or less, preferably It is reduced to 5% by mass or less. The first
In the drying step, by drying in the relatively low temperature range, it is possible to perform the drying while suppressing the foaming of the sheet when the solvent volatilizes. Next, in the second drying step, the film peeled from the flat plate or roll is heated and dried in a temperature range from room temperature to 60 ° C. or higher, preferably 70 ° C. to the glass transition temperature (Tg) of the resin, and the residue is left. Solvent concentration is 2 mass% or less, preferably 1 mass%
Or less, more preferably 0.5% by mass or less. In the second drying step, the drying can be promoted while suppressing foaming by drying in the temperature range. Further, after the first drying step, the film may be peeled off from the flat plate or the roll and the second drying step may be carried out, or after the first drying step, the film may be once cooled and then the film. May be peeled from the flat plate or the roll, and the second drying step may be performed.

Next, an example of producing a saturated norbornene resin film by the melt film forming method will be described. Examples of the melt film forming method include a method using a T die, a melt extrusion method such as an inflation method, a calender method, a hot press method, and an injection molding method. Of these, the melt extrusion method using a T die is preferable. The conditions of the melt film forming method are the same as the general conditions used when manufacturing an optical material having a similar glass transition temperature (Tg). For example, in the melt extrusion method using a T-die, it is preferable to select conditions under which the resin temperature is about 240 to 300 ° C., the take-up roll temperature is about 100 to 150 ° C., and the resin sheet can be gradually cooled. Further, on the surface of the film to be produced, surface defects due to a die line or the like may occur, but in order to reduce this, it is preferable to use a structure in which the retention part is minimized as a die. It is preferable to use a die that has as few scratches as possible inside or on the lip.

The thickness of the saturated norbornene resin film used in the present invention is preferably 40 to 300 μm.
0 to 250 μm is more preferable, and 60 to 200 μm is still more preferable. The film forming width is preferably 0.5 m to 4 m,
0.7m-3m are more preferable, and 1m-2.5m are still more preferable. The light transmittance of the saturated norbornene-based resin film is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more.

(Stretched Film) In the present invention, a film having a retardation of 105 nm or more and 300 nm or less is used. As the stretched film, it is preferable to use a crystalline polymer whose elastic modulus can be further increased by stretching. A stretched film of a saturated norbornene-based resin film can be used, but since the saturated norbornene-based resin is an amorphous polymer, stretching does not easily increase the elastic modulus. Therefore, in the present invention, it is preferable to use a stretched film other than the saturated norbornene-based resin film as the film laminated on the other surface of the polarizing film.

As the stretched film, it is preferable to use a film made of cellulose acetate. As the cellulose acetate, triacetyl cellulose and diacetyl cellulose are preferable. Particularly, the degree of acetylation is preferably 57.0 to 62.5%, and 58.0 to 62%.
% Is more preferable, and 59.0 to 61.5% is further preferable. When the acetylation degree is within the above range, a sufficient moisture permeability can be secured. The degree of acetylation means the amount of bound acetic acid per unit mass of cellulose.

The viscosity average degree of polymerization (DP) of the cellulose acetate used in the present invention is preferably 250 or more, more preferably 290 or more. The cellulose acetate used in the present invention has Mw / Mn measured by gel permeation chromatography.
It is preferable that the molecular weight distribution of (Mw is a weight molecular weight and Mn is a number average molecular weight) is narrow. Specifically, Mw / Mn is preferably 1.0 to 1.7, and 1.3 to 1.6.
It is more preferably 5, and most preferably 1.4 to 1.6.

The stretched film may contain a polymer other than cellulose acetate. The content of the polymer other than the cellulose acetate is preferably less than 50% by mass. Examples of polymers other than the cellulose acetate include lower fatty acid esters of cellulose. The lower fatty acid means a fatty acid having 6 or less carbon atoms. The number of carbon atoms is preferably 3 (cellulose propionate) or 4 (cellulose butyrate). Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate may also be used.

Further, the stretched film may contain various additives for various purposes. The stretched film may contain a retardation adjusting agent in order to adjust the retardation. The retardation adjusting agent preferably has a maximum absorption wavelength in the wavelength range of 230 to 360 nm, and preferably has substantially no absorption in the visible region.

The retardation adjusting agent is preferably an aromatic compound having at least two aromatic rings. This "aromatic ring" includes an aromatic heterocycle in addition to an aromatic hydrocarbon ring. The aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring). The aromatic heterocycle is generally an unsaturated heterocycle, preferably a 5-membered ring, a 6-membered ring or a 7-membered ring, and more preferably a 5-membered ring or a 6-membered ring.
The aromatic heterocycle generally has the largest number of double bonds.
As the hetero atom, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable. Examples of aromatic heterocycles include furan ring, thiophene ring, pyrrole ring,
Oxazole ring, isoxazole ring, thiazole ring,
Isothiazole ring, imidazole ring, pyrazole ring, furazan ring, triazole ring, pyran ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,3
A 5-triazine ring is included. Specific examples of the aromatic ring include a benzene ring, a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, a thiazole ring, an imidazole ring,
Triazole ring, pyridine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring are preferred. The compound used as the retardation adjusting agent preferably has 2 to 20 aromatic rings, more preferably 2 to 12 aromatic rings, and 2 to 6 aromatic rings in the structure.
It is most preferable to have one. Further, the molecular weight of the retardation adjusting agent is preferably 300 to 800.

As the aromatic compound that can be used as the retardation adjusting agent, any of the following (a) plate-like compound and (b) rod-like compound is preferable, and these may be used alone or in combination. Good. (A) Plate-shaped compound The plate-shaped compound contains two or more aromatic rings, and when the two aromatic rings have a bond relationship of (a) forming a condensed ring, (b) a direct bond with a single bond. And (c) a bond through a linking group can be classified (because of the aromatic ring, a spiro bond cannot be formed). The bond relationship between the two aromatic rings may be any of (a) to (c).

Examples of the condensed ring of (a) (condensed ring of two or more aromatic rings) include indene ring, naphthalene ring, azulene ring, fluorene ring, phenanthrene ring, anthracene ring, acenaphthylene ring, biphenylene ring, Naphthacene ring, pyrene ring, indole ring, isoindole ring, benzofuran ring, benzothiophene ring, indolizine ring, benzoxazole ring, benzothiazole ring, benzimidazole ring, benzotriazole ring, purine ring, indazole ring, chromene ring, quinoline Ring, isoquinoline ring,
Quinolidine ring, quinazoline ring, cinnoline ring, quinoxaline ring, phthalazine ring, pteridine ring, carbazole ring, acridine ring, phenanthridine ring, xanthene ring, phenazine ring, phenothiazine ring, phenoxathiin ring, phenoxazine ring and thianthrene ring included. A naphthalene ring, an azulene ring, an indole ring, a benzoxazole ring, a benzothiazole ring, a benzimidazole ring, a benzotriazole ring and a quinoline ring are preferable. In the embodiment of (b) in which a single bond is directly connected, it is preferable that the two carbon atoms in the two aromatic rings are directly bonded.
Two aromatic rings may be bonded with two or more single bonds to form an aliphatic ring or a non-aromatic heterocycle between the two aromatic rings.

In the embodiment (c) where the carbon atoms of the aromatic ring are bonded to each other, it is preferable that the carbon atoms of the two aromatic rings are bonded to each other via the linking group. The linking group is an alkylene group, an alkenylene group, an alkynylene group, -CO-, -O-, -NH.
-, -S- or a combination thereof is preferable. Examples of linking groups composed of combinations are shown below. Note that the left-right relationship in the following examples of the linking group may be reversed. c1: -CO-O- c2: -CO-NH- c3: -alkylene-O- c4: -NH-CO-NH- c5: -NH-CO-O- c6: -O-CO-O- c7: -O-alkylene-O-c8: -CO-alkenylene-c9: -CO-alkenylene-NH-c10: -CO-alkenylene-O-c11: -alkylene-CO-O-alkylene-O-CO
-Alkylene-c12: -O-alkylene-CO-O-alkylene-O-
CO-alkylene-O-c13: -O-CO-alkylene-CO-O-c14: -NH-CO-alkenylene-c15: -O-CO-alkenylene-

The aromatic ring and the linking group contained in the aromatic compound may have a substituent. Examples of the substituents are halogen atom (F, Cl, Br, I), hydroxyl, carboxyl, cyano, amino, nitro, sulfo,
Carbamoyl, sulfamoyl, ureido, alkyl group, alkenyl group, alkynyl group, aliphatic acyl group, aliphatic acyloxy group, alkoxy group, alkoxycarbonyl group, alkoxycarbonylamino group, alkylthio group, alkylsulfonyl group, aliphatic amide group, fat Group sulfonamide groups, aliphatic substituted amino groups, aliphatic substituted carbamoyl groups, aliphatic substituted sulfamoyl groups, aliphatic substituted ureido groups and non-aromatic heterocyclic groups are included.

The alkyl group preferably has 1 to 8 carbon atoms. A chain alkyl group is preferable to a cyclic alkyl group, and a straight chain alkyl group is particularly preferable. The alkyl group may further have a substituent (eg, hydroxy, carboxy, alkoxy group, alkyl-substituted amino group). Examples of alkyl groups (including substituted alkyl groups) include methyl, ethyl, n-butyl, n-hexyl, 2-hydroxyethyl, 4-carboxybutyl, 2
-Methoxyethyl and 2-diethylaminoethyl are included. The alkenyl group preferably has 2 to 8 carbon atoms. A chain alkenyl group is preferable to a cyclic alkenyl group, and a straight chain alkenyl group is particularly preferable. The alkenyl group may further have a substituent. Examples of alkenyl groups include vinyl, allyl and 1-
Hexenyl is included. The alkynyl group preferably has 2 to 8 carbon atoms. A chain alkynyl group is preferable to a cyclic alkynyl group, and a straight chain alkynyl group is particularly preferable. The alkynyl group may further have a substituent. Examples of alkynyl groups include ethynyl, 1-butynyl and 1-hexynyl.

The number of carbon atoms of the aliphatic acyl group is 1 to
It is preferably 10. Examples of aliphatic acyl groups include:
Includes acetyl, propanoyl and butanoyl.
The aliphatic acyloxy group preferably has 1 to 10 carbon atoms. Examples of aliphatic acyloxy groups include:
Includes acetoxy. The alkoxy group preferably has 1 to 8 carbon atoms. The alkoxy group may further have a substituent (eg, an alkoxy group).
Examples of alkoxy groups (including substituted alkoxy groups) include methoxy, ethoxy, butoxy and methoxyethoxy. The alkoxycarbonyl group preferably has 2 to 10 carbon atoms. Examples of the alkoxycarbonyl group include methoxycarbonyl and ethoxycarbonyl. The number of carbon atoms of the alkoxycarbonylamino group is preferably 2-10. Examples of the alkoxycarbonylamino group include methoxycarbonylamino and ethoxycarbonylamino.

The number of carbon atoms in the alkylthio group is 1 to
12 is preferable. Examples of alkylthio groups include:
Includes methylthio, ethylthio and octylthio. The alkylsulfonyl group has 1 to 8 carbon atoms.
Is preferred. Examples of the alkylsulfonyl group include methanesulfonyl and ethanesulfonyl. The number of carbon atoms of the aliphatic amide group is preferably 1-10. Examples of the aliphatic amide group include acetamide. The number of carbon atoms of the aliphatic sulfonamide group is preferably 1-8. Examples of the aliphatic sulfonamide group include methanesulfonamide, butanesulfonamide and n-octanesulfonamide. The aliphatic substituted amino group has 1 carbon atom.
It is preferably 10 to 10. Examples of the aliphatic substituted amino group include dimethylamino, diethylamino and 2-
Carboxyethylamino is included. The aliphatic substituted carbamoyl group preferably has 2 to 10 carbon atoms. Examples of the aliphatic substituted carbamoyl group include methylcarbamoyl and diethylcarbamoyl. The aliphatic substituted sulfamoyl group has 1 to 8 carbon atoms.
Is preferred. Examples of the aliphatic substituted sulfamoyl group include methylsulfamoyl and diethylsulfamoyl. The number of carbon atoms of the aliphatic substituted ureido group is preferably 2-10. Examples of the aliphatic substituted ureido group include methylureido. Examples of the non-aromatic heterocyclic group include piperidino and morpholino.

(B) Rod-Shaped Compound As the retardation adjusting agent, a rod-shaped compound having an absorption maximum on the shorter wavelength side than 250 nm is also preferable.
Specifically, a rod-shaped compound having at least two aromatic rings is preferable, and a linear rod-shaped compound having a thermodynamically most stable structure is more preferable. The most stabilized structure of a compound can be obtained by molecular orbital calculation in addition to crystal structure analysis. Molecular orbital calculation software (WinMOPAC2000, manufactured by Fujitsu Ltd.) can be used to calculate the molecular orbital to obtain the molecular structure that minimizes the heat of formation of the compound. In the present specification, in the molecular structure obtained by such a calculation, a compound having a molecular structure angle of 140 degrees or more is called a linear compound, and a rod-shaped compound having such a structure is preferable as a retardation adjusting agent. .

As the linear rod-shaped compound, a compound having a structure represented by the following general formula (A) is preferable. General formula (A) Ar ¹ -L ¹ -X-L ² -Ar ^{2 In the} general formula (A), Ar ¹ and Ar ² each independently represent an aromatic group, and L ¹ and L ² are independent of each other. do it,
-OCO- represents an alkylene group or an alkyleneoxy group, and X represents a single bond, an ethylene group, an acetylene group or a 1,4-cyclohexylene group. Further, in the general formula (A), the angle formed by Ar ¹ , X and Ar ² is 14
It is preferably 0 degrees or more.

In the formula, Ar ¹ and Ar ² each independently represent an aromatic group. The aromatic ring includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring. It is particularly preferable that the aromatic hydrocarbon ring is a 6-membered ring (that is, a benzene ring). The aromatic heterocycle is generally an unsaturated heterocycle. The aromatic heterocycle is preferably a 5-membered ring, a 6-membered ring or a 7-membered ring, more preferably a 5-membered ring or a 6-membered ring. The aromatic hetero ring generally has the largest number of double bonds. As a hetero atom, a nitrogen atom,
Oxygen atom and sulfur atom are preferable, and nitrogen atom or sulfur atom is particularly preferable. Examples of the aromatic hetero ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazan ring,
It includes a triazole ring, a pyran ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a 1,3,5-triazine ring.

The aromatic ring is preferably a benzene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring or pyrazine ring. The number of aromatic rings contained in the rod-shaped compound is preferably 2 to 20, and more preferably 2 to 12.

The aromatic ring contained in the rod-shaped compound may have a substituent. Examples of the substituent include a halogen atom (specifically F, Cl, Br, I), a hydroxy group,
Carboxyl group, cyano group, amino group (eg, unsubstituted amino group, N-methylamino group, N-ethylamino group, butylamino group, N, N-dimethylamino group, etc.), nitro group, sulfo group, carbamoyl Groups (eg,
An unsubstituted carbamoyl group, an N-methylcarbamoyl group,
N-ethylcarbamoyl group, N, N-dimethylcarbamoyl group, etc.), sulfamoyl group (eg, unsubstituted sulfamoyl group, N-methylsulfamoyl group, N-ethylsulfamoyl group, N, N-dimethylsulfamoyl group) Moyl group, etc., ureido group (eg, unsubstituted ureido group, N-methylureido group, N, N-dimethylureido group, N, N, N'-trimethylureido group, etc.), alkyl group (eg, methyl group) , Ethyl group, propyl group, butyl group, pentyl group, heptyl group, octyl group, isopropyl group, s-butyl group, tert-amyl group, etc.),
Alkenyl group (eg vinyl group, allyl group, hexenyl group etc.), alkynyl group (eg ethynyl group, butynyl group etc.), acyl group (eg formyl group, acetyl group, butyryl group, hexanoyl group, lauryl group etc.) , An acyloxy group (for example, an acetyloxy group, a butyryloxy group, a hexanoyloxy group, a lauryloxy group, etc.), an alkoxy group (for example, a methoxy group, an ethoxy group, a propyloxy group, a butoxy group, a pentyloxy group, a heptyloxy group, Octyloxy group etc.), aryloxy group (eg phenoxy group etc.), alkoxycarbonyl group (eg methoxycarbonyl group, ethoxycarbonyl group, propyloxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl group, heptyloxycarbonyl group) Group), an aryloxycarbonyl group (e.g., a phenoxycarbonyl group), an alkoxycarbonylamino group (e.g., butoxycarbonylamino group, such as hay sill butyloxycarbonylamino group),
Alkylthio group (for example, methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group,
Heptylthio group, octylthio group, etc., arylthio group (eg, phenylthio group, etc.), alkylsulfonyl group (eg, methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, butylsulfonyl group, pentylsulfonyl group, heptylsulfonyl group, octylsulfonyl group) Etc.), an acylamino group (for example, an acetylamino group, a butyrylamino group, a hexanoylamino group,
Laurylamino group), a non-aromatic cyclic hydrocarbon group (eg, cyclohexyl group, cyclopentyl group, etc.), and a non-aromatic heterocyclic group (eg, morpholyl group, pyrazinyl group, etc.).

The substituent is preferably a halogen atom, a cyano group, a carboxyl group, a hydroxy group, an amino group, an acyl group, an acyloxy group, an acylamino group, an alkoxycarbonyl group, an alkoxy group, an alkylthio group or an alkyl group. The group, acyl group, acyloxy group, acylamino group, alkoxycarbonyl group, alkoxy group, alkylthio group and alkyl group may further have a substituent, and examples of the substituent include the aromatic substituents described above. The ones mentioned are preferred. More preferred are a halogen atom, a hydroxy group, an amino group, an acyl group, an acyloxy group, an acylamino group, an alkoxycarbonyl group, an alkoxy group and an alkyl group.

In the general formula (A), L ¹ and L ²
Each independently represents -OCO-, an alkylene group or an alkyleneoxy group. Examples of the alkylene group include methylene, ethylene, trimethylene and propylene groups. Examples of the alkyleneoxy group include methyleneoxy, ethyleneoxy and tripropyleneoxy groups. L ¹ and L ² are preferably an alkyleneoxy group or —OCO—.

In the general formula (A), X is a single bond,
It represents an ethylene group, an acetylene group or a 1,4-cyclohexylene group. X preferably represents an ethylene group, an acetylene group or a 1,4-cyclohexylene group, more preferably an acetylene group or a trans-1,4-cyclohexylene group. In the general formula (A), L ¹ -X
Of the partial structure represented by -L ² , preferably trans-
1,4-cyclohexanedicarbonyloxy, trans-
A 1,4-cyclohexanedicarboxylic acid residue and an acetylenedicarboxylic acid residue.

Specific examples of the compound represented by the general formula (A) are shown below, but the invention is not limited thereto.

[0058]

[Chemical 1]

[0059]

[Chemical 2]

[0060]

[Chemical 3]

[0061]

[Chemical 4]

[0062]

[Chemical 5]

[0063]

[Chemical 6]

[0064]

[Chemical 7]

[0065]

[Chemical 8]

[0066]

[Chemical 9]

These compounds can be synthesized according to synthetic methods known in the literature. For example, Mol. Cryst. Liq. Cryst., 5
Volume 3, 229 (1979); Volume 89, 93 (1
982); 145, 111 (1987); 17
Volume 0, page 43 (1989); J. Am. Chem. Soc., 11
Vol. 3, 1349 (1991); 118, 5346 (1996); 92, 1582 (1970);
J. Org. Chem., 40, 420 (1975); Tetr
ahedron, Vol. 48, No. 16, page 3437 (1992); These compounds may be used alone or as a mixture of two or more compounds.

It is preferable to use an aromatic compound having two aromatic rings as the retardation adjusting agent because a retardation value is not constant and a film having a retardation gradient depending on wavelength is obtained ( The gradient of retardation will be described later). The aromatic compound is preferably added in an amount of 0.01 to 10 parts by mass with respect to 100 parts by mass of cellulose acetate,
It is more preferable to add 0.1 to 8 parts by mass, and further preferable to add 1 to 7 parts by mass.

A plasticizer may be added to the stretched film in order to improve the mechanical properties or improve the drying speed. A phosphoric acid ester or a carboxylic acid ester is used as the plasticizer. Examples of the phosphoric acid ester include triphenyl phosphate (TP
P) and tricresyl phosphate (TCP). Typical carboxylic acid esters are phthalic acid esters and citric acid esters. Examples of phthalates include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DB
P), dioctyl phthalate (DOP), diphenyl phthalate (DPP) and diethylhexyl phthalate (DEHP). Examples of citrate esters include:
Includes O-acetyl triethyl citrate (OACTE) and O-acetyl tributyl citrate (OACTB). Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters. Phthalates plasticizer (DMP, DEP, DBP, D
OP, DPP, DEHP) are preferably used. DE
P and DPP are particularly preferred. The preferable addition amount of the plasticizer varies depending on the material of the film, but for example, when it is added to the cellulose acetate film, it is preferably 0.1 to 25 mass% with respect to the amount of cellulose acetate, and It is more preferably 20% by mass, and most preferably 3 to 15% by mass.

On the stretched film, a deterioration inhibitor (eg,
Antioxidants, peroxide decomposers, radical inhibitors, metal deactivators, acid scavengers, amines) may be added. Regarding the deterioration preventive agent, JP-A-3-199201 and 5-
No. 1907073, No. 5-194789, No. 5-27
No. 1471 and No. 6-107854. The addition amount of the deterioration inhibitor is preferably 0.01 to 1 mass% of the solution (dope) to be prepared, and 0.01 to 1% by mass.
It is more preferably 0.2% by mass. If the addition amount is less than 0.01% by mass, the effect of the deterioration inhibitor is hardly recognized. If the amount added exceeds 1% by mass, the deterioration inhibitor bleeds out on the film surface.
May be recognized. Butylated hydroxytoluene (BHT) and tribenzylamine (TBA) can be mentioned as examples of particularly preferable deterioration preventing agents.

In the present invention, when a cellulose acetate film is used as the stretched film, it is preferable to use a cellulose acetate film formed by a solution casting method. In the solution casting method, a resin solution prepared by dissolving cellulose acetate in a solvent (hereinafter sometimes referred to as a dope) is cast on a substrate (band, drum), and then stripped and dried to form a film. Each step will be described in detail below: Cellulose acetate flakes are dissolved in an organic solvent to prepare a dope, wherein the organic solvent is an ether having 3 to 12 carbon atoms and 3 to 12 carbon atoms. It is preferable to include a solvent selected from the group consisting of the ketone, the ester having 3 to 12 carbon atoms, and the halogenated hydrocarbon having 1 to 6 carbon atoms.
The ether, ketone and ester may have a cyclic structure. Functional groups of ethers, ketones and esters (ie -O-, -CO- and -COO-)
A compound having two or more of any of the above can also be used as the organic solvent. The organic solvent may have another functional group such as an alcoholic hydroxyl group. In the case of an organic solvent having two or more kinds of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group.

Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of the ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexanone. 3 to 12 carbon atoms
Examples of the esters of include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate.
Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol. The number of carbon atoms in the halogenated hydrocarbon is preferably 1 or 2, and most preferably 1. The halogen of the halogenated hydrocarbon is preferably chlorine. The proportion of hydrogen atoms in the halogenated hydrocarbon substituted with halogen is preferably 25 to 75 mol%, and 30 to 7
More preferably 0 mol%, 35-65 mol%
Is more preferable and 40 to 60 mol% is most preferable. Methylene chloride is a typical halogenated hydrocarbon. You may mix and use 2 or more types of organic solvents.

The dope can be prepared by using the dope preparing method and apparatus in the usual solution casting method. It is preferable to use a halogenated hydrocarbon (particularly methylene chloride) as an organic solvent for dissolving the cellulose acetate. The concentration of the polymer in the dope is preferably 10 to 40% by mass, more preferably 10 to 30% by mass. The retardation adjusting agent and optional additives described above can be added to the organic solvent (main solvent). The dope can be prepared by stirring the polymer and the organic solvent at room temperature (0 to 40 ° C). The highly concentrated solution may be stirred under pressure and heat. Specifically, the polymer and the organic solvent are placed in a pressure vessel and sealed, and the mixture is stirred under pressure while heating to a temperature not lower than the boiling point of the solvent at room temperature and not boiling the solvent. The heating temperature is usually 40 ° C. or higher, preferably 60 to 200 ° C., more preferably 80 to 1
It is 10 ° C.

The components may be roughly mixed in advance and then placed in a container. Moreover, you may throw in in a container one by one. The container must be configured to allow stirring. The container can be pressurized by injecting an inert gas such as nitrogen gas.
Alternatively, the increase in vapor pressure of the solvent due to heating may be used. Alternatively, after sealing the container, each component may be added under pressure. When heating, it is preferable to heat from the outside of the container. For example, a jacket type heating device can be used. It is also possible to heat the entire container by providing a plate heater outside the container and piping to circulate the liquid. It is preferable to provide a stirring blade inside the container and use this to stir. The stirring blade is
The length that reaches the vicinity of the wall of the container is preferable. A scraping blade is preferably provided at the end of the stirring blade in order to renew the liquid film on the wall of the container. Instruments such as a pressure gauge and a thermometer may be installed in the container. Each component is dissolved in a solvent in a container. The prepared dope is cooled and then taken out from the container, or after taking out, it is cooled using a heat exchanger or the like.

The solution can be prepared by the cooling dissolution method. In the cooling dissolution method, it can be dissolved in an organic solvent which is difficult to be dissolved by a usual dissolution method. Even if the solvent is a solvent that can dissolve cellulose acetate by an ordinary dissolution method, the cooling dissolution method has an effect of rapidly obtaining a uniform solution. In the cooling dissolution method, first, cellulose acetate is gradually added to an organic solvent with stirring at room temperature. The amount of cellulose acetate is preferably adjusted so as to be contained in this mixture in an amount of 10 to 40% by mass, and more preferably 10 to 30% by mass. Furthermore, any additives described below may be added to the mixture.

Next, the mixture is subjected to -100 to -10 ° C (preferably -80 to -10 ° C, more preferably -50 to-° C).
20 ° C, most preferably -50 to -30 ° C). For cooling, for example, a dry ice / methanol bath (-
75 ° C) or cooled diethylene glycol solution (-30
~ -20 ° C). When cooled in this way,
The mixture of cellulose acetate and organic solvent solidifies.
The cooling rate is preferably 4 ° C / min or more, 8 ° C
/ Min or more is more preferable, and 12 ° C / min or more is most preferable. The faster the cooling rate, the more preferable, but 10,000 ° C./sec is the theoretical upper limit, and 10
00 ° C./sec is the technical upper limit and 100 ° C./sec is the practical upper limit. The cooling rate is a value obtained by dividing the difference between the temperature at the start of cooling and the final cooling temperature by the time from the start of cooling until the final cooling temperature is reached.

Further, when this is heated to 0 to 200 ° C. (preferably 0 to 150 ° C., more preferably 0 to 120 ° C., most preferably 0 to 50 ° C.), the cellulose acetate is dissolved in the organic solvent. The temperature may be raised by leaving it at room temperature or by heating it in a warm bath. The heating rate is preferably 4 ° C./min or more, more preferably 8 ° C./min or more, most preferably 12 ° C./min or more. The faster the heating rate, the better,
10000 ° C / sec is the theoretical upper limit, 1000 ° C / sec
Seconds is the technical upper limit and 100 ° C./sec is the practical upper limit. The heating rate is a value obtained by dividing the difference between the temperature at the start of heating and the final heating temperature by the time from the start of heating until the final heating temperature is reached. .
A uniform solution is obtained as described above. If the dissolution is insufficient, the cooling and heating operations may be repeated. Whether or not the dissolution is sufficient can be judged only by visually observing the appearance of the solution.

In the cooling dissolution method, it is desirable to use a closed container in order to avoid mixing of water due to dew condensation during cooling. In the cooling and heating operation, pressure is applied during cooling,
If the pressure is reduced during heating, the dissolution time can be shortened. In order to carry out the pressurization and depressurization, it is desirable to use a pressure resistant container. A 20% by mass solution of cellulose acetate (acetylation degree: 60.9%, viscosity average degree of polymerization: 299) dissolved in methyl acetate by a cooling dissolution method was 3% by differential scanning calorimetry (DSC).
A quasi-phase transition point between a sol state and a gel state exists near 3 ° C., and at this temperature or lower, a uniform gel state is obtained. Therefore,
This solution must be maintained at a temperature not lower than the pseudo phase transition temperature, preferably about 10 ° C. plus the gel phase transition temperature. However, this pseudo-phase transition temperature differs depending on the degree of acetylation of cellulose acetate, the viscosity average degree of polymerization, the solution concentration and the organic solvent used.

Next, the prepared dope is cast on a substrate to form a polymer film. A film can be formed by casting a dope on a substrate such as a drum or band and evaporating the solvent on the substrate. The dope before casting is preferably adjusted in concentration so that the solid content is 18 to 35%. The surface of the drum or band is preferably mirror-finished. Regarding the casting and drying methods in the solution casting method, US Pat. No. 2,336,310,
2367603, 2492078, and 2492.
No. 977, No. 2492978, No. 2607704,
No. 2739069, No. 2739070, British Patent 6
Nos. 40731 and 736892, Japanese Patent Publication No. 4
5-4554, 49-5614, JP-A-60-1
No. 76834, No. 60-203430, No. 62-11
It is described in each publication of No. 5035.

The dope is preferably cast on a drum or band having a surface temperature of 10 ° C. or lower. After casting, it is preferable to apply air for 2 seconds or more to dry. The obtained film can be peeled off from the drum or band, and dried by hot air whose temperature is successively changed from 100 to 160 ° C. to evaporate the residual solvent. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, the time from casting to stripping can be shortened. In order to carry out this method, it is necessary for the dope to gel at the surface temperature of the drum or band during casting.

It is also possible to produce casting films of two or more layers by using the same or different dope (different in material or material concentration, etc.). For example, it is carried out by casting a solution containing cellulose acetate from a plurality of casting ports provided at intervals in the traveling direction of the support and stacking the solutions. For example, JP-A-61-158414 and JP-A-1-
The methods described in various publications such as No. 122419 and JP-A No. 11-198285 can be applied. Alternatively, by using two casting ports, the film formed on the support by the first casting port is peeled off, and the second casting is performed on the side in contact with the surface of the support, thereby forming a multilayer structure. You may make a film of
For example, the method described in JP-B-44-20235 can be applied. When stacking and casting in this way,
The polymers in the dope used for forming each layer may be the same or different. In order to provide multiple layers with functions (eg, adhesive layer, dye layer, antistatic layer, antihalation layer, UV absorbing layer, etc.), dope containing materials corresponding to the functions is applied from each casting port. It may be extruded. Further, a mat layer containing a matting agent and a polymer may be provided on one side or both sides in order to improve handleability during manufacturing. As the matting agent and the polymer, the materials described in JP-A-10-44327 can be preferably used. In addition, JP-A-56-
It is also possible to increase the casting speed by wrapping the flow of the high-viscosity cellulose acetate solution described in Japanese Patent No. 162617 in a low-viscosity cellulose acetate solution and simultaneously extruding the high- and low-viscosity cellulose acetate solutions.

After casting in this manner, the film is peeled off from the band or drum and dried at 70 ° C. to 200 ° C. for 0.1 to 3 hours to reduce the amount of residual solvent. It is preferable to reduce the residual solvent amount to 2% or less. The width of the film thus formed is 0.5 m to 4
m is preferable, 0.7 m to 3 m is more preferable, and 1 m to
2.5 m is more preferable. The thickness is preferably 40 to 300 μm, more preferably 50 to 250 μm, and 60 to 2
00 μm is more preferable. The light transmittance of the film is 8
0% or more is preferable, 85% or more is more preferable, 90
% Or more is more preferable.

The cellulose acetate film obtained by the solution casting method had a retardation of 55.
At 0 nm, 105 nm to 300 nm, more preferably 115 nm to 200 nm or less, still more preferably 1
Stretching is performed so as to be 25 nm to 180 nm or less. Also,
When the refractive index nx in the in-plane stretching axis direction, the refractive index ny in the direction perpendicular to the in-plane stretching axis and the refractive index nz in the thickness direction of the stretched cellulose acetate film are NZ value = (nx-nz ) / (Nx-ny) is preferably more than 1.1 and 3 or less, more preferably more than 1.3 and 2.5 or less, still more preferably more than 1.5 and 2.2 or less. The NZ value is the ratio of the in-plane refractive index to the thickness direction,
That is, it is the ratio of the orientation in the thickness direction to the in-plane orientation. The fact that NZ is large indicates that the orientation in the thickness direction is advanced and the molecules are densely arranged side by side along the thickness direction. Such a film can increase the elastic modulus even at the same stretch ratio, which is preferable.

In order to prepare such a thickness-oriented film, it is preferable to stretch at a narrow interval. Normal,
Stretching is performed by making the peripheral speed on the outlet side faster than the peripheral speed on the inlet side between two pairs of nip rolls, but it is preferable to stretch by narrowing the gap between the nip rolls. Generally, by stretching, the width of the film becomes narrower (neck-in), but by narrowing the nip roll interval, the neck-in can be made smaller. That is, since both ends of the film are width-regulated by the nip rolls, the stretching is completed before the neck-in can be sufficiently performed, so that the neck-in can be reduced. Normally, the film is necked-in by the stretched amount in order to recover the stretched film in the stretching direction. However, when the film is stretched with a narrow nip roll interval, the neck-in cannot be sufficiently performed, so that the thickness is reduced. For this reason,
As it is rolled up and down, the orientation in the thickness direction is easily aligned, and the orientation in the thickness direction becomes possible. Specifically, when the width of the film before stretching is W and the distance between stretchings (distance between two pairs of nip rolls) is L, it is preferable that 0.3 ≦ L / W ≦ 2. 4 ≦ L / W ≦ 1.7 is more preferable, and 0.6 ≦ L / W ≦ 1.5 is further preferable. For reference, the L / W is about 3 or more in the conventional general stretching method.

When the film is stretched while suppressing neck-in in this way, film breakage easily occurs during stretching. As measures against this, there are a method of increasing the stretching temperature and a method of adding a plasticizing solvent. The former is not preferable because additives (such as a plasticizer described later) are volatilized by heat during stretching. Therefore, the latter is preferable, and in the case of the cellulose acetate film, water can be preferably used as the plasticizing solvent. Specifically, before carrying out the stretching step, water is added to the cellulose acetate film so that the water content is 2% to 1%.
It is preferably 0%, more preferably 2.5% to 8%, still more preferably 3% to 6%.

In order to adjust the water content within the above range, the cellulose acetate film may be immersed in water or exposed to water vapor before stretching. When immersed in water, the water temperature is preferably 60 ° C to 100 ° C, more preferably 70 ° C to 100 ° C, and further preferably 80 ° C to 100 ° C.
℃. In a state where the polymer film is stretched, it is conveyed and conveyed in a water tank having a water temperature in the above range for preferably 0.1 to 20 minutes, more preferably 0.2 to 10 minutes, and further preferably 0.5 to 5 minutes. Can be made to contain water. When exposed to water vapor, the temperature is preferably 60
℃ ~ 150 ℃, more preferably 70 ℃ ~ 140 ℃, more preferably 75 ℃ ~ 130 ℃, relative humidity is preferably 70% ~ 100%, more preferably 80% ~ 100%.
Or less, more preferably 85% to 100% or less of water vapor, preferably 0.1 to 20 minutes, and more preferably 0.
The polymer film is exposed for 2 to 10 minutes, more preferably 0.5 to 5 minutes. Water can be contained by transporting it through a room filled with water vapor under the above conditions.

The water used for immersion or steam aeration may be substantially water. Substantially water refers to water in which 60% by mass or more is water, and may include an organic solvent, a plasticizer, a surfactant and the like in addition to water. Examples of preferable organic solvents include water-soluble organic solvents having 1 to 10 carbon atoms. However, it is most preferable to use pure water. These methods may be carried out in combination or may be carried out alone. Above all, it is preferable to carry out the steam method alone.

After adjusting the water content to the above range, the cellulose acetate film is stretched. The stretching preferably has a temperature of 70 ° C to 120 ° C, more preferably 75 ° C to 110 ° C.
C., more preferably 80.degree. C. to 100.degree. C., preferably 70% to 100% relative humidity, more preferably 75% to 9%.
It is carried out in an atmosphere of 8%, more preferably 80% to 95%. For stretching under the atmosphere, for example, two or more pairs of nip rolls are installed in a casing made of a heat insulating material, air adjusted to the temperature and humidity is introduced therein, and a film is inserted between the nip rolls. And then stretching. The temperature and humidity can be adjusted by mixing steam and the outside air, and a heater may be used for the adjustment.

At the time of stretching, it is preferable that the temperature and humidity at both ends are higher than those in the central part in order to ensure uniform physical properties in the width direction of the film. Stretching is performed at 10 ° C. to 25 ° C., relative humidity at both ends is preferably 5% to 30%, more preferably 10% to 25%, higher than the central portion. These may be carried out in combination, or may be carried out independently. The stretching is preferably performed in multiple stages, more preferably 2 to 10 stages, and further preferably 2 to 7 stages. Stretching can be performed by making the rotation speed of the exit side (post-stage) nip roll faster than the rotation speed of the inlet side (front stage) nip roll. The ratio of the rotational speed of the latter stage (roll diameter multiplied by the number of revolutions) to the rotational speed of the former stage is defined as the draw ratio. In the case of multi-stage stretching, the product of remarkable stretching ratios is taken as the stretching ratio, but the preferred stretching ratio is 1.1 to 2 times, more preferably 1.2.
Double to 1.8 times, and more preferably 1.3 to 1.7 times.

The interval between these nip rolls is the above-mentioned W.
It is preferable to lay out so as to have a / L ratio. In the case of multi-stage stretching, at least one pair of nip roll intervals in the stretching may be within the above W / L ratio range.

The thus obtained stretched acetyl cellulose film has a thickness of preferably 30 μm to 250 μm, more preferably 50 μm to 200 μm, and further preferably 70 μm to 160 μm. The width after film formation is preferably 0.4 m to 3.8 m,
6m-2.6m are more preferable, and 0.8m-2.2m are still more preferable.

In order that the polarizing plate of the present invention functions as a circularly polarizing plate having a wide band in visible light and the visibility (viewing angle) is improved when incorporated into an image display device such as a liquid crystal display device, stretching is required. It is preferable that the retardation value of the film is not constant, but is inclined according to the wavelength. Specifically, the retardation value (R
e550) is 105 nm <Re550 ≦ 330 nm, and the retardation values Re450, Re550 and Re6 measured at wavelengths of 450 nm, 550 nm and 650 nm.
The ratio of 50 is 0.5 <Re450 / Re550 <
0.98, 1.01 <Re650 / Re550 <1.3
It is preferably 5. More preferably 0.6 <Re
450 / Re550 <0.96, 1.03 <Re650
/Re550<1.25, and more preferably 0.7
<Re450 / Re550 <0.94, 1.05 <Re
650 / Re550 <1.2. The gradient of retardation can be realized by adding the above-mentioned aromatic compound having two aromatic rings to the cellulose acetate film as a retardation adjusting agent.

(Production of Polarizing Plate) The saturated norbornene-based resin film, the polarizing film and the stretched film produced as described above can be laminated and adhered with an adhesive layer or the like if desired. Since the saturated norbornene-based resin film is hydrophobic and has low adhesiveness with other films and the like, it is preferable that the saturated norbornene-based resin film is surface-treated and then adhered to the polarizing film or the like. Examples of the surface treatment include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment and ultraviolet irradiation treatment. Of these, corona discharge treatment, glow discharge treatment, and flame treatment are preferable. Regarding corona discharge treatment, JP-A-2000-241627 and JP-A-2
No. 001-350018, etc., glow discharge treatment can be performed according to the method described in JP-A-2000-43202, and flame treatment can be performed according to the method described in JP-A No. 10-151709.

A polarizing film or the like can be laminated and adhered to the surface of the saturated norbornene-based resin film which has been subjected to the surface treatment. In order to further improve the adhesiveness, an adhesive layer or an adhesive layer is attached to the surface-treated surface. It is also possible to form an agent layer and bond it to a polarizing film or the like via these layers. For example, in the case of adhering to a polyvinyl alcohol-based polarizing film, an aqueous solution of polyvinyl alcohol (1% by mass to 30% by mass) is applied to the surface-treated surface of a saturated norbornene-based resin film and dried to form a polyvinyl alcohol layer. However, it is preferable to adhere to the polarizing film via the layer. In addition, it can be laminated with a polarizing film via a pressure-sensitive adhesive layer or an adhesive layer formed by using the following pressure-sensitive adhesive or adhesive.

As the above-mentioned pressure-sensitive adhesive, one having excellent transparency, small birefringence, etc., and capable of exhibiting sufficient pressure-sensitive adhesive force even when used as a thin layer is preferable. Examples of such an adhesive include natural rubber, synthetic rubber / elastomer (styrene / butadiene rubber, etc.), vinyl chloride / vinyl acetate copolymer, polyvinyl alkyl ether, polyacrylate, modified polyolefin resin adhesive, and the like. A curable pressure-sensitive adhesive obtained by adding a curing agent such as isocyanate to these is particularly preferable, and a curable pressure-sensitive adhesive is particularly preferable among pressure-sensitive adhesives used for adhesion of a polyolefin foam or a polyester film. Further, as the adhesive, any adhesive used for bonding polyethylene, polypropylene or the like can be used for laminating the thermoplastic saturated norbornene resin sheet on the polarizing film. For example, a dry laminating adhesive that mixes a polyurethane-based resin solution and a polyisocyanate resin solution, a styrene-butadiene rubber-based adhesive, an epoxy-based two-component curable adhesive, for example, a two-component epoxy resin and polythiol, an epoxy It is possible to use, for example, a two-component resin and a polyamide, and a solvent type adhesive and an epoxy two-component curable adhesive are particularly preferable, and a transparent one is preferable. Some adhesives can improve the adhesive strength by using an appropriate adhesive primer, and when such an adhesive is used, it is preferable to use the adhesive primer.
The thickness of these adhesive layers and pressure-sensitive adhesive layers is usually 1 to 40 μm.
m is suitable.

When a cellulose acetate film is used as the stretched film, it is preferable that the cellulose acetate film is also surface-treated in order to achieve adhesion with the polarizing film and the like. Examples of the surface treatment include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment and ultraviolet irradiation treatment. Of these treatments, acid treatment or alkali treatment is particularly preferable, and alkali treatment (alkali saponification) is more preferable. As a result, the cellulose acetate is hydrolyzed, hydroxyl groups are generated on the surface, and this interacts with the material of the polarizing film (particularly PVA) to improve the adhesiveness.

The alkali saponification is preferably carried out by a cycle in which the film surface is immersed in an alkaline solution, neutralized with an acidic solution, washed with water and dried. Examples of the alkaline solution include potassium hydroxide solution and sodium hydroxide solution, and the specified concentration of hydroxide ion is 0.1N.
To 3.0 N, preferably 0.5 N to 2.0 N
Is more preferable. The temperature of the alkaline solution is
The range of room temperature to 90 ° C is preferable, and the range of 40 ° C to 70 ° C is more preferable. These alkaline solutions may be aqueous solutions,
It may be an organic solvent. In the case of organic dissolution, lower alcohol is preferable, more preferably alcohol or glycol having 1 to 5 carbon atoms, more preferably ethanol,
n-propanol, iso-propanol, butanol,
They are ethylene glycol and propylene glycol. More preferred are isopropanol and propylene glycol. You may mix and use these. Further, water or a surfactant may be added.

Preferred solvents for the alkaline solution used in the alkaline saponification treatment are shown below. The cellulose acetate film is preferably subjected to alkali saponification treatment using an alkali solution prepared by dissolving an alkali such as sodium hydroxide in these solvents. The film may be dipped in an alkaline solution, or the alkaline solution may be applied to the film (bar coating, curtain coating, etc.). Isopropanol / Propylene glycol / Water (70 /
15/15: volume ratio) isopropanol / water (85/15: volume ratio) isopropanol / propylene glycol (85/1
5: volume ratio) isopropanol (100: volume ratio)

A polarizing film or the like can be laminated and adhered on the surface-treated surface of the cellulose acetate film. Further, in order to improve the adhesiveness, an adhesive layer or a pressure-sensitive adhesive layer may be formed on the surface-treated surface, and the surface may be bonded to a polarizing film or the like via these layers. For example, in the case of adhering to a polyvinyl alcohol-based polarizing film, an aqueous solution of polyvinyl alcohol (1% by mass to 30% by mass) is applied to the surface-treated surface of a saturated norbornene-based resin film and dried to form a polyvinyl alcohol layer. However, it is preferable to adhere to the polarizing film via the layer. In addition, it can be laminated with the polarizing film via the pressure-sensitive adhesive layer or the pressure-sensitive adhesive layer formed by using the pressure-sensitive adhesive or the pressure-sensitive adhesive described above.
Further, on a cellulose acetate film, the method disclosed in
An adhesive layer (undercoat layer) as described in JP-A-333433 may be provided. The thickness of the adhesive layer is preferably 0.1 to 2 μm, more preferably 0.2 μm to 1 μm.

As described above, the cellulose acetate film and the polarizing film are preferably laminated so that the stretching direction (longitudinal direction) of the cellulose acetate film and the absorption axis of the polarizing film are 45 °.

The above-mentioned saturated norbornene-based resin film, cellulose acetate film and the polarizing film may be laminated individually or simultaneously. In the latter case, it can be carried out by applying PVA, the above adhesive or pressure-sensitive adhesive to these surface-treated films, sandwiching the polarizing film between them to form a laminate, and then drying. The drying temperature of the laminate is 40 ° C to 140 ° C.
Is preferable, 45 ° C to 100 ° C is more preferable, and 50 ° C.
-80 degreeC is more preferable. The drying time is preferably 1 minute to 30 minutes in the above temperature range.

The polarizing plate produced by laminating in this way can be incorporated in an image display device by bonding it to another member in the image display device such as a liquid crystal display device. When incorporated in an image display device, it is preferable to adhere a cellulose acetate film having high moisture permeability to another member such as a glass substrate. By incorporating in this way, the moisture permeability of the cellulose acetate film having large moisture permeability can be further suppressed, and sufficient moisture resistance can be achieved even if a film having large moisture permeability such as a cellulose acetate film is used. Further, for the purpose of facilitating the bonding work with other members in the image display device (for example, liquid crystal substrate), it is preferable to provide an adhesive layer on one side. As the adhesive, the above-mentioned adhesive can be used. In this case, it is preferable that a release film or the like is laminated before being incorporated into the image display device, during storage, or the like so as not to stick to surrounding objects.

The polarizing plate of the present invention functions as a circularly polarizing plate. In the polarizing plate of the present invention, the adhesion failure and the decrease in the degree of polarization that occur during long-term aging and high-temperature aging are reduced.
Therefore, when applied to an image display device, especially a liquid crystal display device, it is possible to provide an image display device in which display unevenness caused by the polarizing plate due to long-term aging or high temperature aging is reduced. Hereinafter, an image display device to which the polarizing plate of the present invention is applied will be described with a liquid crystal display device as an example. (Liquid Crystal Display Device) The polarizing plate of the present invention is advantageously used in a liquid crystal display device. As the liquid crystal display device, any of a transmissive type, a reflective type and a transflective type may be used, but the reflective type and the transflective type are particularly preferable. FIG. 2 is a schematic diagram showing the basic configuration of the reflective liquid crystal display device. In the reflective liquid crystal display device shown in FIG. 2, the lower substrate (1), the reflective electrode (2), the lower alignment film (3), the liquid crystal layer (4), the upper alignment film (5) and the transparent electrode ( 6), the upper substrate (7), and the polarizing plate (8) of the present invention. The lower substrate (1) and the reflective electrode (2) form a reflective plate. The lower alignment film (3) and the upper alignment film (5) form a liquid crystal cell. In case of color display,
Further, a color filter layer is provided. The color filter layer is preferably provided between the reflective electrode (2) and the lower alignment film (3) or between the upper alignment film (5) and the transparent electrode (6).

Instead of the reflective electrode (2) shown in FIG. 2, a transparent electrode may be used and a reflective plate may be attached separately. A metal plate is preferable as the reflector used in combination with the transparent electrode. If the surface of the reflector is smooth, only the specular reflection component may be reflected and the viewing angle may be narrowed. Therefore, the uneven structure on the surface of the reflector (described in Japanese Patent No. 275620)
Is preferably introduced. When the surface of the reflection plate is flat (instead of introducing an uneven structure on the surface), a light diffusion film may be attached to one side (cell side or outside) of the polarizing film.

The display mode of the liquid crystal cell is not particularly limited. Any liquid crystal display mode may be used, but preferably TN (twisted nematic) type, S
TN (Supper Twisted Nematic) type or HAN (Hy
brid Aligned Nematic) type, VA (Vertically Allignme)
nt) type, ECB type (Electricaly Controlled Birefrigen
ce), OCB (Optically Compensatory Bend) type, C
It is a PA (Continious Pinwheel Alignment) type.

The twist angle of the TN type liquid crystal cell is 40 to 1
The angle is preferably 00 °, more preferably 50 to 90 °, most preferably 60 to 80 °. The value (Δnd) of the refractive index anisotropy (Δn) of the liquid crystal layer and the thickness (d) of the liquid crystal layer is preferably 0.1 to 0.5 μm, and 0.2 to 0.4 μm. It is more preferable that there is. The twist angle of STN type liquid crystal cell is 1
It is preferably 80 to 360 °, and 220 to 270.
More preferably, The value (Δnd) of the refractive index anisotropy (Δn) of the liquid crystal layer and the thickness (d) of the liquid crystal layer is preferably 0.3 to 1.2 μm, and 0.5
It is more preferable that the thickness is 1.0 μm. In the HAN type liquid crystal cell, it is preferable that the liquid crystal is substantially vertically aligned on one substrate and the pretilt angle on the other substrate is 0 to 45 °. The value (Δnd) of the refractive index anisotropy (Δn) of the liquid crystal layer and the thickness (d) of the liquid crystal layer is 0.1 to
It is preferably 1.0 μm, and 0.3 to 0.8 μm
Is more preferable. The substrate on the side of vertically aligning the liquid crystal may be the substrate on the reflection plate side or the substrate on the transparent electrode side.

In the VA mode liquid crystal cell, rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied. VA
The mode liquid crystal cell includes (1) a VA mode liquid crystal cell in a narrow sense in which rod-like liquid crystal molecules are aligned substantially vertically when no voltage is applied, and are aligned substantially horizontally when voltage is applied (Japanese Patent Laid-Open No. 2-176625). (2) A liquid crystal cell in which the VA mode is multi-domained is included in order to expand the viewing angle. Specifically, MVA (SID97, Digest of tech. Papers
(Proceedings) 28 (1997) 845, SID99, Dige
st of tech. Papers (Proceedings) 30 (1999) 206
And JP-A-11-258605), SURV
AIVAL (Monthly Display, Volume 6, Issue 3 (19
99) 14), PVA (Asia Display)
98, Proc. Of the 18th Inter.Display res. Conf. (Proceedings) (1998) 383), Para-A (LCD
/ Presented at PDP International '99), DDVA (SID98, Digest of tech. Papers
(Proceedings) 29 (1998) 838), EOC (S
ID98, Digest of tech. Papers (Proceedings) 29 (1
998) 319), PSHA (SID98, Digest
of tech. Papers 29 (1998) 1081
), RFFMH (Asia Display98, P
roc. of the 18th Inter. Display res. Conf. (Proceedings)
(1998) 375), HMD (SID98, Dige
st of tech. Papers 29 (1998) 702
Description) is included. In addition, (3) a liquid crystal cell (IWD'98, Proc. Of the 5th In) in which a rod-shaped liquid crystal molecule is substantially vertically aligned when no voltage is applied and twisted in a multi-domain alignment when a voltage is applied (IWD'98, Proc. Of the 5th In
ter. Display Workshop. (Proceedings) (1998, 143))).

In the OCB mode, an alignment mode liquid crystal cell is used in which rod-shaped liquid crystalline molecules are aligned in substantially opposite directions (symmetrically) in the upper part and the lower part of the liquid crystal cell. As a result, it has self-optical compensation capability. See US Patent 458 for details
3825 and 54410422. The ECB mode is characterized in that the liquid crystal is aligned horizontally, and details thereof are described in JP-A-5-203946. The reflective and semi-transmissive liquid crystal display devices can be used in a normally white mode in which a bright display is displayed when the applied voltage is low and a dark display when the applied voltage is high, or in a normally black mode where a dark display is displayed when the applied voltage is low and a bright display is displayed when the applied voltage is high. , Can be used. Normally white mode is preferred.

The polarizing plate of the present invention can be applied to a touch panel or an organic EL display device. The touch panel is disclosed in JP-A-5-127822 and Japanese Patent Application No. 2000-2.
It can be applied to those described in the specification of No. 36797. Japanese Patent Laid-Open No. 11-30572 discloses an organic EL display device.
No. 9, JP-A No. 11-307250, and JP-A-2000
It can be applied to those described in JP-A-267097.

[0110]

EXAMPLES The present invention will be described in more detail with reference to the following examples. The materials, reagents, ratios, operations and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. In the following, "parts" and "%" are based on mass unless otherwise specified.

In the examples, the physical properties of the samples were measured by the following methods. Measurement of Retardation The sample film was conditioned for 1 day at a temperature of 25 ° C and a relative humidity of 60%, and then an automatic birefringence meter (KOBRA-21ADH / PR:
(Oji Keisoku Co., Ltd.) in the phase difference measurement mode, and measured at a wavelength of 550 nm from the direction perpendicular to the surface of the sample film, which was used as the retardation (Re55
0). Further, the retardations at 450 nm and 650 nm were measured in the same manner, and they were respectively Re450 and Re650. From these values, Re450 / Re550, Re6
50 / Re550 was calculated.

NZ value ((nx-nz) / (nx-n)
y)) Using an ellipsometer (KOBRA-21ADH / PR: manufactured by Oji Scientific Instruments Co., Ltd.), the wavelength is 550 nm from the direction perpendicular to the film surface and inclined by 40 degrees or -40 degrees.
Retardation was measured with Re (0), R
e (40) and Re (-40) were obtained. From this, the refractive index nx in the slow axis direction, the refractive index ny in the direction perpendicular to the in-plane slow axis, and the refractive index nz in the thickness direction are obtained, and (nx-n
The value of z) / (nx-ny) was calculated. A water content sample (2 pieces of 0.9 m × 4.5 cm) was weighed, immediately put in a glass bottle with a polishing stopper, sealed, and measured within 3 minutes by the Karl Fischer method described below. Moisture in the sample was volatilized at 150 ° C. using a vaporizer (VA-05 type manufactured by Mitsubishi Chemical) and introduced into a moisture meter (Karl Fischer moisture meter; CA-03 type manufactured by Mitsubishi Chemical) for measurement. The water content (μg) indicated by the water content meter was W, the sample amount weighed was F (mg), and the water content was calculated from the following formula. Moisture content (%) = 0.1 x (W / F)

Acetylation degree ASTM: D-817-91 (testing method for cellulose acetate etc.) acetyl number average molecular weight It was measured by GPC method using toluene as a solvent. The hydrogenation rate was measured by 1H-NMR. Glass transition temperature (Tg) It was measured by the DSC method. The light transmittance was measured with a light transmittance spectrophotometer while continuously changing the wavelength in the wavelength range of 400 to 700 nm, and the minimum transmittance was defined as the light transmittance. The residual solvent concentration of the film was measured by gas chromatography at 200 ° C.

(1) Preparation of Saturated Norbornene-Based Resin Film A saturated norbornene-based resin film was prepared by any of the following film-forming methods (described in Table 1). (1-1) Synthesis of saturated norbornene-based resin 6-methyl-1,4,5,8-dimethano-1,4,4
To a, 5,6,7,8,8a-octahydronaphthalene (hereinafter abbreviated as MTD), 10 parts of 15% cyclohexane solution of triethylaluminum, 5 parts of triethylamine, and 20% cyclohexane solution of titanium tetrachloride are used as polymerization catalysts. 10 parts of it was added and the ring-opening polymerization was carried out in cyclohexane, and the obtained ring-opening polymer was hydrogenated with a nickel catalyst to obtain a polymer solution. The polymer solution was coagulated in isopropyl alcohol and dried to obtain a powdery resin. The number average molecular weight of this resin was 40,000, the hydrogenation rate was 99.8% or more, and the Tg was 142 ° C.

(1-2) Solution Casting 15 parts by mass of the saturated norbornene resin were dissolved in 85 parts by mass of xylene, and a leveling agent (Florard FC) was added to the solution.
-430, Sumitomo 3M) 500ppm and UV stabilizer (Biosorb 80, Kyodo Pharmaceutical) 300pp
m and 30 ppm of colloidal silica (particle size 0.5 μm) were added to obtain a resin solution composition. This resin solution composition (dope) was filtered and then cast from a T-die onto a stainless steel endless band using a gear pump. This was dried on a band until the residual solvent was 20%, then stripped off and dried in a drying zone at 110 ° C. until the residual solvent was 1% or less. After that, both ends were trimmed, knurled on both ends, and then wound.
The film thus obtained has a width of 1.5 m and a length of 3
It was 000 m. The surface of this film was observed visually and by an optical microscope, but no foaming, lines, scratches, etc. were observed. The Tg of the obtained film was 138 ° C. The average thickness is shown in Table 1. The thickness unevenness was ± 3% or less, the light transmittance was 91.0%, and the haze was 1% or less.

(1-3) Melt Film Formation The saturated norbornene resin synthesized in (1-1) was pelletized and then dried at 120 ° C. for 30 minutes. This was melted at 300 ° C. using a melt extruder, filtered with a sintering filter, and extruded from a T-die onto a casting drum at 100 ° C. After peeling it off, it was wound after trimming both ends. The film thus obtained had a width of 1.5 m and a length of 3000 m. The surface of this film was observed visually and by an optical microscope, but no foaming, lines, scratches, etc. were observed. Tg of film is 1
The average thickness at 38 ° C. is shown in Table 1. Thickness unevenness is ± 3%
Hereinafter, the light transmittance was 91.0% and the haze was 1% or less.

[0117]

[Table 1]

(2) Preparation of Cellulose Acetate Film (2-1) Preparation of Dope MC type and MA type cellulose acetate dope (high concentration solution) having the following composition was prepared. As the aromatic compound used as the retardation adjusting agent, the compounds having the following structural formulas were used. It is described in Table 2.

[0119]

[Chemical 10]

[0120] (A) Methylene chloride (MC) system     Cellulose acetate (Acetification degree is shown in Table 2) 100 parts by mass     Triphenyl phosphate 10.0 parts by mass     Biphenyl diphenyl phosphate 5.0 parts by mass     Methylene chloride 565.6 parts by mass     Methanol 49.2 parts by mass     Aromatic compound (retardation adjusting agent)     Silica fine particles (particle size 20 nm) 0.05 parts by mass

[0121] (B) Methyl acetate (MA) system     Cellulose acetate (Acetification degree is shown in Table 2) 118 parts by mass     Triphenyl phosphate 9.19 parts by mass     Biphenyl diphenyl phosphate 4.60 parts by mass     2.36 parts by mass of tribenzylamine     Methyl acetate 530 parts by mass     Ethanol 99.4 parts by mass     Butanol 33.1 parts by mass     Aromatic compound (retardation adjusting agent)     Silica fine particles (particle size 20 nm) 0.05 parts by mass

The MC type dope was prepared by the following room temperature dissolution method, and the MA type dope was prepared by the following cooling dissolution method. (A) Room temperature dissolution method The above compound was gradually added to the solvent with good stirring, and allowed to swell at room temperature (25 ° C) for 3 hours. The swelling mixture obtained is placed in a mixing tank with a reflux condenser for 5 minutes.
It dissolved at 0 ° C. with stirring. (B) Cooling dissolution method The above compound was gradually added to the solvent with good stirring, and allowed to swell at room temperature (25 ° C) for 3 hours. While slowly stirring the obtained swelling mixture, it was cooled to −30 ° C. at −8 ° C./min, then cooled to the temperature shown in Table 2, and after 6 hours, heated at + 8 ° C./min. When the sol formation of the contents had progressed to a certain extent, stirring of the contents was started. The dope was obtained by heating to 50 ° C.

(2-2) Solution Casting Film Formation A film was formed by one of the following two methods to prepare a casting film (described in Table 2). (A) Single-layer casting The solution (dope) obtained by the above method was filtered with a filter paper (No. 244 manufactured by Azumi Filter Paper Co., Ltd.) and a filter cloth made of flannel, and then sent to a pressure die with a fixed gear pump. Liquid, effective length 6
m band casting machine was used. (B) Using a laminated casting three-layer co-casting die, dope of the above composition from the inner layer,
A dope diluted with a solvent amount increased to 10% on both sides is simultaneously discharged onto a metal support to perform multi-layer casting, and then the casting film is peeled from the support and dried to form a three-layer structure laminate. (Thickness of inner layer: thickness of each surface layer = 8: 1) was manufactured.

Next, when the residual solvent reached 20% by mass, the casting film was peeled off from the support. The cast film peeled off was passed through a drying zone at 120 ° C., and the residual solvent was 1% by mass.
Dry until: Then, after trimming both ends, knurling (thickness processing) having a height of 50 μm and a width of 1 cm was performed on both ends to obtain an unstretched film having a length of 3000 m and a width of 1.5 m.

(2-3) Stretching Prior to stretching, the cellulose acetate film was exposed to water vapor to have the water content shown in Table 2. This was stretched under the conditions described in Table 2 (temperature, humidity, stretching ratio, ratio (L / W) of width W of film before stretching and distance L between stretching).

[0126]

[Table 2]

The evaluation results of the stretched film thus obtained are shown in Table 3 below.

[0128]

[Table 3]

(3) Preparation of Polarizing Plate (3-1) Preparation of Polarizing Film (a) 45-degree oriented polarizing film and (b) MD oriented polarizing film were produced by the following methods. (A) A 45 degree oriented polarizing film PVA film was immersed in an aqueous solution of 2.0 g / L of iodine and 4.0 g / L of potassium iodide at 25 ° C. for 240 seconds,
Further, after dipping in an aqueous solution of 10 g / L boric acid at 25 ° C. for 60 seconds, it was introduced into the tenter stretching machine of the form shown in FIG.
It was stretched 5.3 times in 0 ° C. and 90% relative humidity, and the tenter was bent in the stretching direction as shown in FIG. 1, and thereafter the width was kept constant. After being dried in an atmosphere of 80 ° C., it was separated from the tenter. The difference in transport speed between the left and right tenter clips is 0.
It was less than 05%, and the angle between the center line of the film introduced and the center line of the film sent to the next step was 46 °. Here, | L1-L2 | was 0.7 m, W was 0.7 m, and there was a relationship of | L1-L2 | = W. The substantial stretching direction Ax-Cx at the exit of the tenter was inclined by 45 ° with respect to the center line 22 of the film sent to the next step.

(B) MD oriented polarizing film The PVA film was immersed in an aqueous solution of 2.0 g / L of iodine and 4.0 g / L of potassium iodide for 240 seconds at 25 ° C., and then further immersed in an aqueous solution of 10 g / L boric acid for 25 seconds. After dipping at 60 ° C. for 60 seconds, it was stretched 5.3 times in MD direction (longitudinal direction) at 60 ° C. 90% rh using two pairs of nip rolls, and dried at 80 ° C. The transmission axis is 0 with respect to the center line (MD direction).
It was degree.

(3-2) Surface Treatment of Film Regarding the saturated norbornene resin film, corona treatment was applied to the film surface so that the contact angle of water on the surface was 90 °. The stretched cellulose acetate film was subjected to alkali saponification treatment by coating the alkali treatment liquid on one side with a # 3 bar at 60 ° C., washing with water after 30 seconds and drying. In addition, as the alkali treatment liquid, isopropanol / propylene glycol / water (70/15/1
(5: volume ratio) dissolve potassium hydroxide to a concentration of 1.5 m
An alkaline solution of ol / L was used. For the unstretched cellulose acetate film (trade name: Fujitac (thickness 80 μm): made by Fuji Photo Film),
Similarly, saponification treatment was performed.

(3-3) Bonding PVA (PVA-117H manufactured by Kuraray Co., Ltd.) 3 between the layers
% Aqueous solution as an adhesive while being laminated so as to have the layer structure shown in Table 4. At this time, each of the films was arranged so that the laminated interface was subjected to the above-mentioned surface treatment. Then, it was dried at 60 ° C. for 15 minutes. The stretching axis of the stretched cellulose acetate film and the absorption axis of the polarizing film are shown in Table 4.
The layers were laminated by a roll-to-roll method and attached to each other so as to have an angle described in.

[0133]

[Table 4]

(4) Evaluation (4-1) Evaluation of Adhesion On one surface of the polarizing plate laminated as described above (the rightmost layer in the layer structure in Table 4), an adhesive (diabond) having a thickness of about 8 μm was used. DA 753, manufactured by Nogawa Chemical Co., Ltd., thickness 1.
It was laminated on a 2 mm glass substrate. Humidity 90% Temperature 80 ° C
The heat cycle test of 1 hour at -20 ° C. and 1 hour at -20 ° C. was repeated for 2000 cycles. Then, Table 5 shows the area where bubbles called tunnels due to poor adhesion were generated.

(4-5) Evaluation of Degree of Polarization Degree Before the above heat cycle, the same polarizing plates were combined in crossed Nicols and the light transmittance at 500 nm was measured, which was designated as T0 (%). It measured similarly after the said heat cycle, and made this T1 (%). (T1-T0) / T
Table 5 shows 0 as the amount of decrease in the polarization degree.

(5) Fabrication of liquid crystal display device (5-1) TN type reflection type liquid crystal display device A glass substrate provided with an ITO transparent electrode and a glass substrate provided with an aluminum reflection electrode having fine irregularities are provided. I prepared. A polyimide alignment film (SE-7992, manufactured by Nissan Chemical Industries, Ltd.) was formed on each of the two glass substrates on the electrode side, and a rubbing treatment was performed. Two substrates were stacked with the alignment films facing each other through a 1.7 μm spacer. The orientation of the substrate was adjusted so that the rubbing directions of the two alignment films intersect at an angle of 110 °. Liquid crystal (MLC-6252, manufactured by Merck) is injected into the gap between the substrates,
A liquid crystal layer was formed. In this way, the twist angle is 70
A TN type liquid crystal cell having a value of ° and Δnd of 269 nm was produced. The polarizing plates prepared by the above (1) to (4) were attached from the side of the cellulose acetate film to the side of the glass substrate provided with the ITO transparent electrode.

In the manufactured reflection type liquid crystal display device, 1 kHz
The rectangular wave voltage of was applied. White display 1.5V, black display 4.
When visually evaluated at 5 V, it was confirmed that neutral gray was displayed in the present invention with no tint in both white display and black display. Next, a measuring machine (EZcontrast 160D, Eldi
When the contrast ratio of the reflection luminance was measured using M. Co., Ltd., the contrast ratio from the front was 25, and the viewing angle at which the contrast ratio was 10 is shown in Table 5. In the present invention, good viewing angles were obtained in all cases. In addition, Table 5 shows the ratio of the contrast at the four points at the four corners (points that make up 5% of the total length) and the contrast at the central portion as display unevenness. The display unevenness of each of the present invention was as good as 1.05 or less. Further, no adhesion failure occurred in the 2000-cycle heat cycle test.

[0138]

[Table 5]

(5-2) STN type reflective liquid crystal display device A glass plate provided with an ITO transparent electrode and a glass substrate provided with a flat aluminum reflective electrode were prepared. The polyimide alignment film (SE
-150, manufactured by Nissan Kagaku Co., Ltd. was formed and subjected to rubbing treatment. Two substrates were stacked with the alignment films facing each other through a 6.0 μm spacer. The orientation of the substrate was adjusted so that the rubbing directions of the two alignment films intersect at an angle of 60 °. Liquid crystal (ZLI-297
7, manufactured by Merck & Co., Inc. was injected to form a liquid crystal layer. In this way, the twist angle is 240 ° and the value of Δnd is 791n.
m STN type liquid crystal cell was produced. An internal diffusion sheet (IDS, manufactured by Dai Nippon Printing Co., Ltd.) and the polarizing plates prepared in (1) to (4) above were adhered to each other in this order on the side of the glass substrate provided with the ITO transparent electrode via adhesive. Then, the polarizing plate was attached so as to be the outermost layer.

The reflection type liquid crystal display device thus produced was
The rectangular wave voltage of was applied. Black display 2.0V, white display 2.
When visually evaluated at 5 V, it was confirmed that neutral gray was displayed in the present invention with no tint in both white display and black display. Next, the contrast ratio of the reflection luminance was measured using a measuring device (EZcontrast 160D, manufactured by Eldim). In the present invention, the contrast ratio from the front is 8
Above, the viewing angle with a contrast ratio of 3 is 9 above and below.
It was good at 0 ° or more and 105 ° or more on the left and right. In addition, the display unevenness was good at 1.05 or less. Further, no adhesion failure occurred in the 2000-cycle heat cycle test.

(5-3) VA Type Liquid Crystal Display Device The VA type liquid crystal display device is, in order from the bottom, a lower glass substrate, an insulating film, a thin film transistor, a reflector, a lower alignment film, a liquid crystal,
The upper alignment film, the ITO transparent electrode, the overcoat layer, the color filter, and the upper glass substrate. A glass substrate provided with an ITO transparent electrode and a glass substrate provided with an aluminum reflective electrode having fine irregularities were prepared. A vertical alignment film (RN7) is used for the upper alignment film and the lower alignment film, respectively.
83, Nissan Chemical Co., Ltd.) was prepared and subjected to rubbing treatment. Two substrates were stacked with the alignment films facing each other through a 1.7 μm spacer. The orientation of the substrate was adjusted so that the rubbing directions of the two alignment films intersect at an angle of 110 °. In the gap between the substrates, Δn = 0.08, Δε
= -4 liquid crystal (manufactured by Merck) was injected by a vacuum injection method to form a liquid crystal layer. Thus, a VA liquid crystal cell having a twist angle of 45 ° and a Δnd value of 135 nm was produced. On the side of the glass substrate provided with the ITO transparent electrode, from the glass substrate side, stretched cellulose acetate film,
A commercially available polarizing film (HLC2-5618HCS, manufactured by Sanritz Co., Ltd.) and a saturated norbornene-based resin film were laminated in this order with an adhesive. When the stretched cellulose acetate film and the commercially available polarizing film were attached to each other, they were attached so that the absorption axis of the polarizing film and the slow axis of the stretched film were 45 degrees. All of the polarizing plates using the polarizing plate of the present invention obtained a good viewing angle of 160 ° or more in the vertical viewing angle and 160 ° or more in the horizontal viewing angle.

Similarly, a VA type liquid crystal cell was prepared and ITO was used.
The polarizing plate of the present invention was attached to the side of the glass substrate provided with the transparent electrode via an adhesive so that the cellulose acetate film side was the glass substrate side. All of the polarizing plates using the polarizing plate of the present invention obtained a good viewing angle of 160 ° or more in the vertical viewing angle and 160 ° or more in the horizontal viewing angle. In addition, the display unevenness was good at 1.05 or less. further,
Adhesion failure did not occur even in the 2000-cycle heat cycle test.

(5-4) ECB type liquid crystal display device According to Example 1 of JP-A-11-316378, the polarizing plate of the present invention was used in place of the second transparent support and the polarizing film. Using this, an ECB type liquid crystal display element was prepared according to Example 6 of JP-A-11-316378. All of the products using the present invention obtained a good viewing angle of 120 ° or more in the vertical viewing angle and 115 ° or more in the horizontal viewing angle. In addition, the display unevenness was good at 1.05 or less. Further, no adhesion failure occurred in the 2000-cycle heat cycle test.

(5-5) Mounting on anti-transmission type product The polarizing plate, the λ / 2 plate and the λ / 4 plate on the upper side of the liquid crystal cell of the liquid crystal display part of Cybershot (manufactured by Sony Corporation) were peeled off, and the glass substrate side From the above, the polarizing plate of the present invention was laminated via a pressure-sensitive adhesive with the cellulose acetate film facing upward. All of the polarizing plates using the polarizing plate of the present invention provided a good viewing angle of 120 ° or more in the vertical viewing angle and 115 ° or more in the horizontal viewing angle. (5-6) Mounting on reflective liquid crystal display device Reflective liquid crystal display device with touch panel (manufactured by Sharp Corporation,
The polarizing plate of the touch panel / polarizing plate / optical compensatory film / liquid crystal cell and the optical compensating film portion were peeled off with a Zaurus) and replaced with the polarizing plate of the present invention. All of the polarizing plates using the polarizing plate of the present invention provided a good viewing angle of 120 ° or more in the vertical viewing angle and 115 ° or more in the horizontal viewing angle. In addition, the display unevenness was good at 1.05 or less. Further, no adhesion failure occurred in the 2000-cycle heat cycle test.

(5-7) Display Device Using Organic EL In accordance with JP 2000-267097 A, the polarizing plate of the present invention has protective tack (with an antireflection layer on the outermost surface) / polarizing plate in order from the viewer side. / Organic EL element / reflection electrode. When the tint was visually evaluated, it was confirmed that coloring was small especially in black display, which resulted in high contrast and excellent visibility. Further, no adhesion failure occurred in the 2000-cycle heat cycle test.

[0146]

As described above, according to the present invention, it is possible to provide a polarizing plate in which the adhesion failure and the decrease in the degree of polarization that occur during long-term aging and high-temperature aging are reduced.
Further, according to the present invention, it is possible to provide a polarizing plate which, when applied to an image display device, particularly a liquid crystal display device, can reduce display unevenness caused by the polarizing plate due to long-term aging or high temperature aging. Further, according to the present invention, it is possible to provide an image display device in which display unevenness caused by a polarizing plate due to long-term aging or high temperature aging is reduced.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an example of a stretching device for producing a polarizing film usable in the present invention.

FIG. 2 is a schematic diagram showing a configuration example of a reflective liquid crystal display device to which the polarizing plate of the present invention is applied.

[Explanation of symbols]

(A) Film introducing direction (b) Film conveying direction to the next step (a) Step of introducing the film (b) Step of stretching the film (c) Step of sending the stretched film to the next step A1 Entrapment position and origin position of film stretching (right) B1 Film entrapment position on the holding means (left) C1 film stretching origin position (left) Cx film release position and film stretching end point reference position (left) Ay film Stretching end point reference position (right) | L1-L2 | Stroke difference between left and right film holding means W Substantial width θ of film at the end of stretching process Angle 21 formed between the stretching direction and the film advancing direction 22 Center line of the introducing side film Center line of the film sent to the film 23 Trajectory of the film holding means (left) 24 Trajectory of the film holding means (right) 25 Introducing film 26 Film 27 ', 27 left and right film holding start (biting) points 28', 28 left and right film holding release points 1 lower substrate 2 reflective electrode 3 lower alignment film 4 liquid crystal layer 5 upper alignment film 6 transparent electrode 7 Upper Substrate 8 Polarizing Plate of the Present Invention

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroaki Sata             Fuji Photo, 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture             Within Film Co., Ltd. F term (reference) 2H049 BA03 BA25 BA27 BB11 BB19                       BB22 BB33 BB43 BB51 BB62                       BC03 BC14 BC21 BC22                 2H091 FA08X FA11X FA16Y FB02                       FB03 FB04 FB12 FC07 FC17                       FC22 FC23 FD06 FD07 FD15                       GA17 HA06 HA07 HA09 HA10                       KA01 KA02 KA03 KA10 LA02                       LA04 LA18

Claims (2)

[Claims] 1. A polarizing plate comprising a polarizing film, a stretched film having a retardation of 105 nm or more and 300 nm or less on one surface of the polarizing film, and a saturated norbornene-based resin film on the other surface of the polarizing film. 2. An image display device provided with the polarizing plate according to claim 1.