JP2014178485A - Polarizing plate and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing plate which is thin, has high pencil hardness on a cellulose acylate film side, and has less leakage of light from corners of a panel after being assembled into a liquid crystal display device and subjected to heat and humidity for a period of time.SOLUTION: A polarizing plate comprises a polarizer, a cycloolefin polymer layer formed on a side of one surface A of the polarizer, and a cellulose acylate film laminated in the described order, and has a thickness of no more than 100 μm. The cellulose acylate film located on the side of the surface A of the polarizer has Knoop hardness of no less than 240 N/mm.

Description

  The present invention relates to a polarizing plate and a liquid crystal display device.

A cellulose acylate film typified by cellulose acetate has high transparency and has been conventionally used for various applications in image display devices. For example, it is used as a polarizing plate protective film in a liquid crystal display device because it can easily ensure adhesion with polyvinyl alcohol used in a polarizer.
In recent years, thinning of liquid crystal display devices, particularly liquid crystal display devices for small and medium-sized applications, has been progressing rapidly. There is an urgent need to reduce the thickness of members (films, polarizing plates).

JP 2008-102475 A JP 2007-256882 A

When the present inventors made the polarizing plate provided in the liquid crystal display device into a thin film, as a new problem with the thinning of the entire polarizing plate, the problem of the pencil hardness decrease on the cellulose acylate film side, and the thin film of the polarizing plate It has been found that there is a problem that light leakage (warp unevenness) at the corners of the panel deteriorates when it is incorporated into a liquid crystal display device accompanying the thinning of the protective film that is indispensable for making the film heat and heat.
Here, as a method for expressing the hardness of a film in which a hard coat layer is provided on a cellulose acylate film or the like, there is known a method expressed by a Knoop hardness of the film in addition to the pencil hardness of the hard coat layer. Knoop hardness is one of the scales representing the hardness of a material, and is a kind of indentation hardness. A polarizing plate having a cycloolefin polymer layer as the outermost layer has a Knoop hardness lower than that when a cellulose acylate film or the like is used as the outermost layer, and has a higher pencil hardness (harder) when a hard coat layer is provided. I found it difficult to do.

  On the other hand, the present inventors have examined that light leakage (warp unevenness) at the corners of the panel when the polarizing plate is incorporated in a liquid crystal display device and has been subjected to wet heat has elapsed when the cellulose acylate film is disposed as a protective film for a polarizer. Further, it has been found that this is caused by an increase in the value of moisture permeability. Here, in Patent Documents 1 and 2, a cellulose acylate film is used as a protective film on one surface of a polarizer, and a low moisture permeability such as a cycloolefin resin film is used as a protective film on the other surface of the polarizer. A method using a film is described. However, in Examples of Patent Documents 1 and 2, there is no description of an example in which the thickness of the entire polarizing plate is 100 μm or less, and in Examples of Patent Document 1, protective films having a thickness of about 70 to 80 μm are provided on both surfaces of the polarizer. In the example of Patent Document 2, the thickness of the protective film in which various functional layers are provided on the cycloolefin-based resin film used as the protective film on one surface of the polarizer greatly exceeds 100 μm. In view of the thickness of the adhesive layer, Patent Documents 1 and 2 have not suggested that the thickness of the entire polarizing plate be controlled to 100 μm or less.

  The problem to be solved by the present invention is to provide a polarizing plate that is a thin film, has a high pencil hardness on the cellulose acylate film side, and has little light leakage at the corners of the panel when it is incorporated into a liquid crystal display and aged over time. It is.

  When the present inventors diligently studied for the purpose of solving the above-mentioned problems, in a polarizing plate thinned to a specific range, a cycloolefin polymer layer and a cellulose acylate film are formed on one side of the polarizer. By laminating in this order and controlling the knoop hardness of the cellulose acylate film or the cellulose acylate film after applying the hard coat layer to a specific range, the inventors have obtained knowledge that the above problems can be solved. The present invention has been completed through repeated studies.

The present invention which is means for solving the above problems is as follows.
[1] A polarizer,
A cycloolefin polymer layer disposed on one side A of the polarizer;
Cellulose acylate film in this order,
The thickness is 100 μm or less,
A polarizing plate characterized in that the Knoop hardness of the cellulose acylate film disposed on the surface A side of the polarizer is 240 N / mm ² or more.
[2] A polarizer,
A cycloolefin polymer layer disposed on one side A of the polarizer;
Cellulose acylate film in this order,
The thickness is 100 μm or less,
A polarizing plate having a Knoop hardness of 265 N / mm ² or more when a hard coat layer is laminated on the cellulose acylate film disposed on the surface A side of the polarizer.
[3] In the polarizing plate according to [1] or [2], the thickness of the cellulose acylate film disposed on the surface A side of the polarizer is preferably 35 μm or less.
[4] In the polarizing plate according to any one of [1] to [3], a second cellulose acylate film is further disposed on the surface B side opposite to the surface A of the polarizer. Is preferred.
[5] In the polarizing plate according to [4], it is preferable that a second cycloolefin polymer layer is further disposed between the surface B of the polarizer and the second cellulose acylate film. .
[6] The polarizing plate according to [4] or [5] is obtained by further polymerizing an ethylenically unsaturated monomer between the surface B of the polarizer and the second cellulose acylate film. It is preferred that the layers are arranged.
[7] In the polarizing plate according to any one of [4] to [6], an ethylenically unsaturated monomer is further polymerized between the surface B of the polarizer and the second cellulose acylate film. It is preferable that the layer and the second cycloolefin polymer layer are arranged in this order.
[8] In the polarizing plate according to any one of [5] to [7], the thickness of the second cycloolefin polymer layer disposed on the surface B side of the polarizer is preferably 15 μm or less. .
[9] In the polarizing plate according to any one of [4] to [8], Rth of the second cellulose acylate film disposed on the surface B side of the polarizer is −10 to 10 nm. (Rth represents retardation in the film thickness direction).
[10] The polarizing plate according to any one of [1] to [9] is further ethylenically unsaturated between the cycloolefin polymer layer disposed on the surface A side of the polarizer and the polarizer. It is preferable that a layer formed by polymerizing monomers is disposed.
[11] In the polarizing plate according to any one of [1] to [10], the thickness of the cycloolefin polymer layer disposed on the surface A side of the polarizer is preferably 15 μm or less.
[12] In the polarizing plate according to any one of [1] to [11], a hard coat layer may be further disposed on the cellulose acylate film disposed on the surface A side of the polarizer. preferable.
[13] In the polarizing plate according to any one of [1] to [12], the thickness of the polarizer is preferably 15 μm or less.
[14] The polarizing plate according to any one of [1] to [13] preferably has a thickness of less than 80 μm.
[15] A liquid crystal display device comprising a liquid crystal cell and at least one polarizing plate according to any one of [1] to [14].
[16] In the liquid crystal display device according to [15], the cellulose acylate film in which the cycloolefin polymer layer disposed on the surface A side of the polarizer is disposed on the surface A side of the polarizer. It is preferable that the polarizing plate is disposed so as to be closer to the liquid crystal cell.

  According to the present invention, it is possible to provide a polarizing plate that is a thin film, has a high pencil hardness on the cellulose acylate film side, and has little light leakage at the corners of the panel when it is incorporated into a liquid crystal display and aged with heat and humidity.

FIG. 1 is a schematic view showing a cross section of an example of the structure of the polarizing plate of the present invention. FIG. 2 is a schematic view showing a cross section of the structure of another example of the polarizing plate of the present invention. FIG. 3 is a schematic view showing a cross section of the structure of another example of the polarizing plate of the present invention. FIG. 4 is a schematic view showing a cross section of the structure of another example of the polarizing plate of the present invention. FIG. 5 is a schematic view showing a cross section of the structure of another example of the polarizing plate of the present invention. FIG. 6 is a schematic view showing a cross section of the structure of another example of the polarizing plate of the present invention. FIG. 7 is a schematic view showing a cross section of another example of the structure of the polarizing plate of the present invention. FIG. 8 is a schematic view showing a cross section of the structure of another example of the polarizing plate of the present invention. FIG. 9 is a schematic view showing a cross section of the structure of another example of the polarizing plate of the present invention.

  Hereinafter, the contents of the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

[Polarizer]
1st aspect of the polarizing plate of this invention has a polarizer, the cycloolefin polymer layer arrange | positioned at the one surface A side of this polarizer, and a cellulose acylate film in this order, and thickness is The polarizing plate is 100 μm or less, and the Knoop hardness of the cellulose acylate film disposed on the surface A side of the polarizer is 240 N / mm ² or more.
The second aspect of the polarizing plate of the present invention is a polarizer,
A cycloolefin polymer layer disposed on one side A of the polarizer;
Cellulose acylate film in this order,
The thickness is 100 μm or less,
The polarizing plate is characterized in that a Knoop hardness when a hard coat layer is laminated on the cellulose acylate film arranged on the surface A side of the polarizer is 265 N / mm ² or more.
With such a configuration, it is possible to obtain a polarizing plate that is a thin film, has a high pencil hardness on the cellulose acylate film side, and has little light leakage at the corners of the panel when it is incorporated into a liquid crystal display and aged over time.
When the Knoop hardness of the cellulose acylate film is increased, the pencil hardness of the protective film coated with the cellulose acylate film or the hard coat layer laminated thereon is also increased. In addition, it is considered that the pencil hardness decreases when the cellulose acylate film is thinned because the film rigidity (hardness × film thickness) decreases even if the film has the same hardness. Therefore, a thin film is required to have a higher Knoop hardness.
Furthermore, by using a cycloolefin polymer layer between the cellulose acylate film and the polarizer, the dimensional change due to thermo (wet heat) environmental changes is suppressed, and the corner of the panel when it is incorporated into a liquid crystal display and aged with heat and heat. Can improve light leakage.
Furthermore, in a more preferred embodiment of the polarizing plate of the present invention, the viewing angle color change when incorporated in a liquid crystal display device can be suppressed by bringing Rth of the protective film on the surface B side close to zero.
Hereinafter, the preferable aspect of the polarizing plate of this invention is demonstrated.

<Characteristics of polarizing plate>
The total thickness of the polarizing plate of the present invention is 100 μm or less, preferably 95 μm or less, more preferably less than 80 μm, particularly preferably 20 to 75 μm, and more preferably 30 to 75 μm. More particularly preferred.

<Configuration of polarizing plate>
First, a possible configuration and a preferable configuration of the polarizing plate of the present invention will be described with reference to the drawings.
1-9 is the schematic which shows the cross section of the structure of an example of the polarizing plate of this invention.

  In FIG. 1, a polarizer 1, a cycloolefin polymer layer 2A disposed on one surface A side of the polarizer 1, and a cellulose acylate film 3A disposed on one surface A side of the polarizer 1 are illustrated. The polarizing plate of the aspect which has these in this order is shown.

In the polarizing plate of the present invention, it is preferable that a hard coat layer is further disposed on the cellulose acylate film disposed on the surface A side of the polarizer.
As a specific example of the polarizing plate in such an embodiment, FIG. 2 shows a polarizer 1, a cycloolefin polymer layer 2A disposed on the surface A side of the polarizer 1, and the surface A side of the polarizer 1. The polarizing plate of the aspect by which the hard-coat layer 10 was further arrange | positioned on the said cellulose acylate film 3A arrange | positioned in 3 and the said cellulose acylate film 3A is shown.

In the polarizing plate of the present invention, a layer formed by further polymerizing an ethylenically unsaturated monomer is disposed between the cycloolefin polymer layer disposed on the surface A side of the polarizer and the polarizer. preferable.
As a specific example of the polarizing plate in such an embodiment, FIG. 3 shows a polarizer 1, a layer 4A obtained by polymerizing an ethylenically unsaturated monomer, the cycloolefin polymer layer 2A, and the cellulose acylate film 3A. The polarizing plate of the aspect by which the hard-coat layer 10 is arrange | positioned in this order is shown.

In the polarizing plate of the present invention, it is preferable that a second cellulose acylate film is further disposed on the surface B side opposite to the surface A of the polarizer.
As a specific example of the polarizing plate of such an embodiment, FIG. 4 shows a polarizer 1, the cycloolefin polymer layer 2A on one surface A side of the polarizer 1, the cellulose acylate film 3A, and the hard coat. The polarizing plate of the aspect by which the layer 10 is arrange | positioned in this order and the 2nd cellulose acylate film 3B is further arrange | positioned by the surface B side on the opposite side to the said surface A of the said polarizer 1 is shown.

In the polarizing plate of the present invention, it is preferable that a second cycloolefin polymer layer is further disposed between the surface B of the polarizer 1 and the second cellulose acylate film.
As a specific example of the polarizing plate of such an embodiment, FIG. 5 shows a polarizer 1, the cycloolefin polymer layer 2A on one surface A side of the polarizer 1, the cellulose acylate film 3A, and the hard The coating layer 10 is arranged in this order, and the second cycloolefin polymer layer 2B and the second cellulose acylate film 3B are arranged in this order on the surface B side of the polarizer 1. A polarizing plate is shown.

In the polarizing plate of the present invention, it is preferable that a layer formed by polymerizing an ethylenically unsaturated monomer is further disposed between the surface B of the polarizer 1 and the second cellulose acylate film.
As a specific example of such a polarizing plate, FIG. 6 shows a polarizer 1, the cycloolefin polymer layer 2A on one surface A side of the polarizer 1, the cellulose acylate film 3A, and a hard coat. The layer 10 is arranged in this order, and the layer 4B formed by polymerizing an ethylenically unsaturated monomer and the second cellulose acylate film 3B are arranged in this order on the surface B side of the polarizer 1. The polarizing plate of the made aspect is shown.

In the polarizing plate of the present invention, a layer obtained by further polymerizing an ethylenically unsaturated monomer and the second cycloolefin polymer layer between the surface B of the polarizer 1 and the second cellulose acylate film. Are preferably arranged in this order.
As a specific example of the polarizing plate in such an embodiment, FIG. 7 shows a polarizer 1, the cycloolefin polymer layer 2A on one surface A side of the polarizer 1, the cellulose acylate film 3A, and the hard The coating layer 10 is arranged in this order, and on the surface B side of the polarizer 1, a layer 4B obtained by polymerizing an ethylenically unsaturated monomer, a second cycloolefin polymer layer 2B, and the second The polarizing plate of the aspect with which the cellulose acylate film 3B was arrange | positioned in this order is shown.

The polarizing plate of the present invention is not contrary to the spirit of the present invention, and as long as the thickness of the polarizing plate is 100 μm or less, the layer formed by polymerizing the ethylenically unsaturated monomer on both sides of the polarizer, the cyclohexane The olefin polymer layer and the cellulose acylate film may all be included, and further the hard coat layer may be included.
As a specific example of such a polarizing plate, FIG. 8 shows a layer 4A obtained by polymerizing an ethylenically unsaturated monomer on the surface A side of the polarizer 1, the cycloolefin polymer layer 2A, and the cellulose acylate. A film 3A, the hard coat layer 10 is disposed, a layer 4B obtained by polymerizing an ethylenically unsaturated monomer on the surface B side of the polarizer 1, a second cycloolefin polymer layer 2B, and the second The cellulose acylate film 3B of this is the polarizing plate of the aspect arrange | positioned in this order.

As long as the polarizing plate of this invention is not contrary to the meaning of this invention, layers other than a cellulose acylate film may be arrange | positioned further on the said surface B side of the said polarizer.
As a specific example of the polarizing plate in such an embodiment, FIG. 9 shows a polarizer 1, the cycloolefin polymer layer 2A on one surface A side of the polarizer 1, the cellulose acylate film 3A, and the hard The coating layer 10 is arrange | positioned in this order, The polarizing plate of the aspect by which layers 5 other than a cellulose acylate film are arrange | positioned further on the said surface B side of the said polarizer is shown.
Next, the preferable aspect of each member which comprises these polarizing plates of this invention is demonstrated.

<Polarizer>
A conventionally well-known thing can be used as said polarizer.

  As the film thickness of the polarizer, for example, a film having a thickness of 5 to 30 μm is used. In the polarizing plate of the present invention, the thickness of the polarizer is preferably 15 μm or less, more preferably 1 to 15 μm, and particularly preferably 2 to 10 μm.

<Cycloolefin polymer layer, second cycloolefin polymer layer>
The polarizing plate of this invention has a polarizer, the cycloolefin polymer layer arrange | positioned at the one surface A side of this polarizer, and a cellulose acylate film in this order.
In the polarizing plate of the present invention, it is preferable that a second cycloolefin polymer layer is further disposed between the surface B of the polarizer and the second cellulose acylate film.
The preferable aspect of the cycloolefin polymer layer disposed on one surface A side of the polarizer is the same as the preferable aspect of the second cycloolefin polymer layer disposed on the surface B side of the polarizer. For this reason, the cycloolefin polymer layer will be collectively described below.
However, in the polarizing plate of the present invention, the cycloolefin polymer layer disposed on the one surface A side of the polarizer and the second cycloolefin polymer layer disposed on the surface B side of the polarizer are the same. Or they may be different from each other.

(Composition of cycloolefin polymer layer)
Examples of the cycloolefin polymer layer include a layer formed from a composition containing as a main component a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule.
In the present invention, the layer formed from the composition containing as a main component a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule is a cyclic aliphatic group for imparting low moisture permeability. Contains a compound having a hydrocarbon group and an unsaturated double bond group in the molecule, and further contains a polymerization initiator, a translucent particle, a fluorine-containing or silicone compound, and a solvent as necessary. It is preferable to form the composition by coating, drying, and curing directly on the support or through another layer. Each component will be described below. In addition, the main component of a composition or a layer means the component which occupies 50 mass% or more of the composition or the layer.

[Compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule]
A compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule functions as a binder. In addition, a compound having a cycloaliphatic hydrocarbon group and an unsaturated double bond group can function as a curing agent, and can improve the strength and scratch resistance of the coating film, while at the same time being low. Moisture permeability can be imparted.
By using such a compound, low moisture permeability and high film strength can be realized. Although the details are not clear, by using a compound having a cycloaliphatic hydrocarbon group in the molecule, a hydrophobic cycloaliphatic hydrocarbon group is introduced into the low moisture-permeable layer, and is hydrophobized. Prevents uptake of molecules and reduces moisture permeability. Moreover, by having an unsaturated double bond group in a molecule | numerator, a crosslinking point density is raised and the diffusion path | route of the water molecule in a low moisture-permeable layer is restrict | limited. Increasing the crosslink point density also has the effect of relatively increasing the density of the cyclic aliphatic hydrocarbon group, making the inside of the low moisture permeable layer more hydrophobic, preventing the adsorption of water molecules, and reducing the moisture permeability. it is conceivable that.
In order to increase the crosslinking point density, the number of unsaturated double bond groups in the molecule is more preferably 2 or more.

The cyclic aliphatic hydrocarbon group is preferably a group derived from an alicyclic compound having 7 or more carbon atoms, more preferably a group derived from an alicyclic compound having 10 or more carbon atoms, and further preferably Is a group derived from an alicyclic compound having 12 or more carbon atoms.
The cycloaliphatic hydrocarbon group is particularly preferably a group derived from a polycyclic compound such as bicyclic or tricyclic.
More preferably, the central skeleton of the compound described in the claims of JP-A No. 2006-215096, the central skeleton of the compound described in JP-A No. 2001-10999, or the skeleton of an adamantane derivative may be used.

  As the cyclic aliphatic hydrocarbon group (including a linking group), a group represented by any one of the following general formulas (I) to (V) is preferable, and the following general formula (I), (II), or (IV) Is more preferable, and a group represented by the following general formula (I) is more preferable.

  In general formula (I), L and L 'each independently represent a divalent or higher linking group and are not divalent simultaneously. n represents an integer of 1 to 3.

  In general formula (II), L and L ′ each independently represent a divalent or higher linking group, and are not divalent simultaneously. n represents an integer of 1 to 2.

  In general formula (III), L and L ′ each independently represent a divalent or higher linking group and are not divalent simultaneously. n represents an integer of 1 to 2.

  In general formula (IV), L and L ′ each independently represent a divalent or higher valent linking group, and L ″ represents a hydrogen atom or a divalent or higher valent linking group.

  In general formula (V), L and L ′ each independently represent a divalent or higher valent linking group and are not divalent simultaneously.

  Specific examples of the cyclic aliphatic hydrocarbon group include norbornyl, tricyclodecanyl, tetracyclododecanyl, pentacyclopentadecanyl, adamantyl, diamantanyl and the like.

Examples of the unsaturated double bond group include polymerizable functional groups such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group and —C (O) OCH═CH ₂ Is preferred. Particularly preferably, a compound containing three or more (meth) acryloyl groups in one molecule described below can be used.

A compound having a cycloaliphatic hydrocarbon group and having 3 or more unsaturated double bond groups in the molecule has the above-described cycloaliphatic hydrocarbon group and the group having an unsaturated double bond as a linking group. It is comprised by connecting via.
As the linking group, a single bond, an alkylene group having 1 to 6 carbon atoms which may be substituted, an amide group which may be substituted at the N-position, a carbamoyl group which may be substituted at the N-position, or an ester group , An oxycarbonyl group, an ether group, and the like, and groups obtained by combining these.

These compounds include, for example, polyols such as diols and triols having the above cyclic aliphatic hydrocarbon groups, and carboxylic acids and carboxylic acid derivatives of compounds having (meth) acryloyl groups, vinyl groups, styryl groups, allyl groups, etc. It can be easily synthesized by a one-step or two-step reaction with an epoxy derivative, an isocyanate derivative or the like.
Preferably, compounds such as (meth) acrylic acid, (meth) acryloyl chloride, (meth) acrylic anhydride, glycidyl (meth) acrylate, and compounds described in WO2012 / 00316A (eg, 1,1-bis ( (Acryloxymethyl) ethyl isocyanate) can be synthesized by reacting with a polyol having the above cyclic aliphatic hydrocarbon group.

  Preferred specific examples of the compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group are shown below, but the present invention is not limited thereto.

Examples of the cycloolefin polymer that can be used in the present invention include (1) a norbornene polymer, (2) a monocyclic cycloolefin polymer, (3) a cyclic conjugated diene polymer, and (4) vinyl. Examples include alicyclic hydrocarbon polymers and hydrides of (1) to (4).
The cycloolefin polymer preferred for the present invention is an addition (co) polymer cyclic polyolefin resin containing at least one repeating unit represented by the following general formula (102) and, if necessary, the general formula (101). It is an addition (co) polymer cyclic polyolefin resin further comprising at least one repeating unit. A ring-opening (co) polymer containing at least one cyclic repeating unit represented by the general formula (103) can also be suitably used.

In formulas (101) to (103), m represents an integer of 0 to 4. R ^{1 to} R ⁶ are a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, X ^{1 to} X ³ and Y ^{1 to} Y ³ are a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, and a halogen atom. substituted hydrocarbon group having 1 to 10 carbon _{atoms, - (CH 2) n COOR} 11, - (CH 2) n OCOR 12, - (CH 2) n NCO, - (CH 2) n NO 2, - ( _{CH 2) n CN, - (} CH 2) n CONR 13 R 14, - (CH 2) n NR 13 R 14, - (CH 2) n OZ, - (CH 2) n W, or X ¹ and Y ¹ Alternatively, (—CO) ₂ O and (—CO) ₂ NR ¹⁵ composed of X ² and Y ² or X ³ and Y ³ are shown. R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , and R ¹⁵ are hydrogen atoms, hydrocarbon groups having 1 to 20 carbon atoms, Z is a hydrocarbon group or a hydrocarbon group substituted with a halogen, and W is SiR ¹⁶ _p. D _3-p (R ¹⁶ is a hydrocarbon group having 1 to 10 carbon atoms, D is a halogen atom, —OCOR ¹⁶ or —OR ¹⁶ , p is an integer of 0 to 3), n is an integer of 0 to 10 Show.

Norbornene polymer hydrides are disclosed in JP-A-1-240517, JP-A-7-196736, JP-A-60-26024, JP-A-62-19807, JP-A-2003-115767, or JP-A-2004-309979. As disclosed in No. 1, etc., a polycyclic unsaturated compound is produced by addition polymerization or metathesis ring-opening polymerization and then hydrogenation. In the norbornene-based polymer used in the present invention, R ^{5 to} R ⁶ are preferably a hydrogen atom or —CH ₃ , X ³ and Y ³ are preferably a hydrogen atom, Cl, —COOCH ₃ , and other groups are appropriately selected. The This norbornene-based resin is sold under the trade name Arton G or Arton F by JSR Corporation, and from Zeon Corporation, Zeonor ZF14, ZF16, Zeonex 250 or Zeonex. They are commercially available under the trade name 280 and can be used.

  Norbornene-based addition (co) polymers are disclosed in JP-A No. 10-7732, JP-T-2002-504184, U.S. Published Patent No. 200429129157A1 or WO2004 / 070463A1. It can be obtained by addition polymerization of norbornene-based polycyclic unsaturated compounds. If necessary, norbornene-based polycyclic unsaturated compounds and ethylene, propylene, butene; conjugated dienes such as butadiene and isoprene; nonconjugated dienes such as ethylidene norbornene; acrylonitrile, acrylic acid, methacrylic acid, maleic anhydride It is also possible to carry out addition polymerization with linear diene compounds such as acid, acrylic acid ester, methacrylic acid ester, maleimide, vinyl acetate and vinyl chloride. This norbornene-based addition (co) polymer is marketed by Mitsui Chemicals, Inc. under the name of Apel, and has different glass transition temperatures (Tg) such as APL8008T (Tg70 ° C), APL6013T (Tg125 ° C) or APL6015T ( Grades such as Tg145 ° C). Pellets such as TOPAS 8007, 6013, and 6015 are sold by Polyplastics Co., Ltd. Further, Appear 3000 is sold by Ferrania.

  In the present invention, the glass transition temperature (Tg) of the cyclic polyolefin-based resin is not limited, but a high-Tg cyclic polyolefin resin such as 200 to 400 ° C. can also be used.

As the cycloolefin polymer layer, a conventionally known optical film can be used.
Examples of the optical film used as the cycloolefin polymer layer include cyclic olefin resin films described in paragraph [0029] and subsequent paragraphs of JP-A-2009-237376, Japanese Patent No. 4881827, and JP-A-2008-063536. A cyclic olefin resin film containing an additive for reducing Rth described in Japanese Unexamined Patent Application Publication Nos. 2008-102475 and 2007-256882 can be used.

(Method for producing cycloolefin polymer layer)
There is no restriction | limiting in particular as a manufacturing method of the said cycloolefin polymer layer, It can manufacture by a well-known method. As an example, the manufacturing method similar to the manufacturing method of the cellulose acylate film mentioned later can be mentioned.

  As the cycloolefin polymer layer, from the viewpoint of thinning, a thin layer formed by coating or the like may be used, and the thin layer does not necessarily have a self-supporting property. For example, after the cycloolefin polymer layer is formed on the temporary support, the cycloolefin polymer layer is bonded to the polarizer directly or via an adhesive layer together with the temporary support, The temporary support may be peeled off and transferred.

(Characteristics of cycloolefin polymer layer)
In the polarizing plate of the present invention, the cycloolefin polymer layer preferably has a thickness of 15 μm or less, more preferably 10 μm or less, and particularly preferably 5 to 10 μm.

  In the polarizing plate of the present invention, Rth of the cycloolefin polymer layer is preferably −10 to 10 nm, more preferably −8 to 8 nm, and particularly preferably −6 to 6 nm. The definition of Rth will be described in the description of the cellulose acylate film described later.

<Layer formed by polymerizing ethylenically unsaturated monomer>
The polarizing plate of the present invention has a layer formed by further polymerizing an ethylenically unsaturated monomer between the surface A of the polarizer and the cellulose acylate film disposed on the surface A side of the polarizer. It is preferable. The polarizing plate of the present invention preferably has a layer formed by polymerizing an ethylenically unsaturated monomer between the surface B of the polarizer and the second cellulose acylate film. A preferred embodiment of a layer formed by polymerizing an ethylenically unsaturated monomer arranged on one side A of the polarizer and a polymerized ethylenically unsaturated monomer arranged on the side B of the polarizer Since the preferable aspect of the layer formed is the same, it will be described below as a layer formed by polymerizing an ethylenically unsaturated monomer.
However, the polarizing plate of the present invention comprises a layer formed by polymerizing an ethylenically unsaturated monomer arranged on one surface A side of the polarizer, and an ethylenically unsaturated material arranged on the surface B side of the polarizer. The layers obtained by polymerizing the monomers may be the same or different from each other.
Conventionally, when a cycloolefin polymer layer or an acrylic polymer layer is used as an inner protective film, the rework performance at the time of panel mounting tended to deteriorate, but the polarizer and the cycloolefin polymer layer or the acrylic polymer layer Reworkability can be imparted by forming a layer formed by polymerizing an ethylenically unsaturated monomer as an adhesion layer.

There is no restriction | limiting in particular as an ethylenically unsaturated monomer which can be used for the layer formed by superposing | polymerizing the said ethylenically unsaturated monomer. As the ethylenically unsaturated monomer, a monomer having two or more unsaturated double bonds in the same molecule and having no alicyclic structure is preferable.
A monomer having two or more unsaturated double bonds in the same molecule and not having an alicyclic structure has a polymerizable functional group such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Examples thereof include (meth) acryloyl group and —C (═O) OCH═CH ₂ . Particularly preferably, a compound containing three or more (meth) acryloyl groups in one molecule described below can be used.

  Specific examples of the compound having a polymerizable unsaturated bond include (meth) acrylic acid diesters of alkylene glycol, (meth) acrylic acid diesters of polyoxyalkylene glycol, and (meth) acrylic acid diesters of polyhydric alcohol. (Meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts, epoxy (meth) acrylates, urethane (meth) acrylates, and polyester (meth) acrylates.

  Among these, esters of polyhydric alcohol and (meth) acrylic acid are preferable. For example, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , Pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, EO modified Tri (meth) acrylate phosphate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate And dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate, caprolactone-modified tris (acryloxyethyl) isocyanurate It is done.

  Commercially available polyfunctional acrylate compounds having a (meth) acryloyl group can be used, such as KAYARAD DPHA manufactured by Nippon Kayaku Co., Ltd., PET-30, Shin Nakamura Chemical Co., Ltd., NK Ester A -TMMT, A-TMPT, etc. can be mentioned.

  In the polarizing plate of the present invention, the thickness of the layer formed by polymerizing the ethylenically unsaturated monomer is preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 2 to 4 μm.

<Cellulose acylate film disposed on the surface A side of the polarizer>
In an embodiment in which the polarizing plate of the present invention is used in a liquid crystal display device, the cellulose acylate film disposed on the surface A side of the polarizer is arranged on the inner side (that is, between the polarizer and the liquid crystal cell) and the outer side (that is, Any arrangement on the side opposite to the liquid crystal surface) can be used preferably, but when it has a hard coat layer, it is preferably arranged outside the display surface.

(Cellulose acylate)
The cellulose acylate film disposed on the surface A side of the polarizer preferably contains cellulose acylate as a main component. The cellulose acylate used in the present invention is not particularly limited. Among them, it is preferable to use cellulose acylate having an acetyl substitution degree of 2.70 to 2.95. It is preferable for the degree of acetyl substitution to be 2.7 or higher because the compatibility with the aromatic ester oligomer that satisfies the conditions described later is good and the film is not easily whitened. Furthermore, in addition to transparency, moisture permeability and water content are favorable, which is preferable. Moreover, the polarizer durability of the polarizing plate and the wet heat durability of the film itself are also favorable, which is preferable. On the other hand, the degree of substitution is preferably 2.95 or less from the viewpoint of optical performance.

The degree of acetyl substitution of the cellulose acylate is more preferably 2.75 to 2.90, and particularly preferably 2.82 to 2.89.
The preferred range of the total acyl substitution degree is the same as the preferred range of the acetyl substitution degree.
In addition, the substitution degree of an acyl group can be measured according to the method prescribed | regulated to ASTM-D817-96. The portion not substituted with an acyl group usually exists as a hydroxyl group.

Among the acyl groups having 2 to 22 carbon atoms to be substituted for the hydroxyl group of cellulose, the acyl group having 2 to 22 carbon atoms may be an aliphatic group or an allyl group, and is not particularly limited. A single or a mixture of two or more types But you can. They are, for example, alkyl carbonyl esters, alkenyl carbonyl esters, aromatic carbonyl esters, aromatic alkyl carbonyl esters, etc. of cellulose, each of which may further have a substituted group. These preferred acyl groups include acetyl, propionyl, butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, iso-butanoyl, t-butanoyl, cyclohexanecarbonyl, Examples include oleoyl, benzoyl, naphthylcarbonyl, and cinnamoyl groups. Among these, acetyl, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl and the like are preferable, and acetyl, propionyl and butanoyl are more preferable.
In the cellulose acylate used in the present invention, the substituent is preferably an acetyl group or a propionyl group, and more preferably an acetyl group.

  In addition, mixed fatty acid cellulose acylate may be used. Specific examples of the mixed fatty acid cellulose acylate include cellulose acetate propionate and cellulose acetate butyrate, and cellulose acetate propionate is preferable.

  The basic principle of the cellulose acylate synthesis method is described in Mita et al., Wood Chemistry pages 180-190 (Kyoritsu Shuppan, 1968). A typical synthesis method is a liquid phase acetylation method using a carboxylic acid anhydride-acetic acid-sulfuric acid catalyst.

The cellulose acylate preferably has a number average molecular weight (Mn) of 40,000 to 200,000, more preferably 100,000 to 200,000. The cellulose acylate used in the present invention preferably has an Mw / Mn ratio of 4.0 or less, more preferably 1.4 to 2.3.
In the present invention, the average molecular weight and molecular weight distribution of cellulose acylate, etc. are calculated by calculating the number average molecular weight (Mn) and the weight average molecular weight (Mw) using gel permeation chromatography (GPC). International Publication WO 2008-126535 The ratio can be calculated by the method described in the publication.

The cellulose acylate film disposed on the surface A side of the polarizer may contain an additive together with cellulose acylate as a main component, and may contain, for example, at least one aromatic ester oligomer. preferable. It is preferable to add an aromatic ester oligomer because the Knoop hardness of the cellulose acylate film disposed on the surface A side of the polarizer can be increased. For example, by subjecting a cellulose acylate film containing an aromatic ester oligomer to stretching treatment (preferably biaxial stretching treatment), the Knoop hardness of the cellulose acylate film disposed on the surface A side of the polarizer can be increased. .
Moreover, in the preferable aspect of the polarizing plate of this invention, the polarization at the time of the thermo process accompanying the increase in the water vapor transmission resulting from the thin film formation of the cellulose acylate film arrange | positioned at the surface A side of a polarizer by adding an additive Improvement in performance deterioration and improvement in polarizer durability can also be achieved. Moreover, in the preferable aspect of the polarizing plate of this invention, the warp nonuniformity when the polarizing plate of this invention is integrated in a liquid crystal display device as a result can also be improved.
Hereinafter, the additive preferably used for the cellulose acylate film disposed on the surface A side of the polarizer will be described.

(Aromatic ester oligomer)
The aromatic ester oligomer used in the present invention will be described.
The aromatic ester oligomer is not particularly limited. Among them, having a repeating unit derived from a dicarboxylic acid and a repeating unit derived from a diol, among the repeating units derived from the dicarboxylic acid, the molar ratio of the repeating unit derived from the aliphatic dicarboxylic acid is m, and the repeating unit derived from the aromatic dicarboxylic acid When the molar ratio of n is n, m: n is preferably 0:10 to 3: 7. When ester oligomers penetrate into the free volume part of cellulose, it is estimated that increasing the phthalic acid ratio increases the hardness derived from the material and increases the Knoop hardness of the film.
Without being bound by any theory, it is possible to increase the Knoop hardness of the cellulose acylate film by using an aromatic ester oligomer, and further to determine the molar ratio of repeating units derived from the aliphatic dicarboxylic acid of the aromatic ester oligomer to m. The Knoop hardness of the cellulose acylate film disposed on the surface A side of the polarizer can be further increased by controlling the molar ratio n of the repeating units derived from the aromatic dicarboxylic acid.
The difference in pencil hardness among thin films is that the penetration into the cellulose acylate film placed on the side of the polarizer surface A of the hard coat layer changes due to the nature of the plasticizer. It is thought to do. It is thought that pencil hardness becomes so low that it is easy to saturate into the cellulose acylate film arrange | positioned at the surface A side of a polarizer.
By using an aromatic ester oligomer, the molar ratio of the repeating unit derived from the aliphatic dicarboxylic acid of the aromatic ester oligomer is m, and the ratio of the molar ratio n of the repeating unit derived from the aromatic dicarboxylic acid is controlled. While increasing Knoop hardness, it is possible to suppress the penetration of the hard coat layer into the cellulose acylate film disposed on the surface A of the polarizer, and to increase the pencil hardness when the hard coat layer is provided.
In addition, by using an aromatic ester oligomer, an optical film having no display unevenness when incorporated in a liquid crystal display device as an optical film disposed inside a polarizer can be provided.

The number average molecular weight (Mn) of the aromatic ester oligomer in the present invention is preferably 600 to 2000, more preferably 600 to 1500, and still more preferably 600 to 1200. If the number average molecular weight of the aromatic ester oligomer is 600 or more, the volatility is low, and film failure and process contamination due to volatilization under high temperature conditions during stretching of the cellulose acylate film are less likely to occur. Moreover, if it is 2000 or less, compatibility with a cellulose acylate will become high and it will become difficult to produce the bleed-out at the time of film forming and a heat-stretching.
The number average molecular weight of the aromatic ester oligomer in the present invention can be measured and evaluated by gel permeation chromatography.

  The aromatic ester oligomer used in the present invention is preferably synthesized from a diol having 2 to 10 carbon atoms and a dicarboxylic acid having 4 to 10 carbon atoms. As the synthesis method, a known method such as a dehydration condensation reaction of a dicarboxylic acid and a diol, or addition of a dicarboxylic anhydride to glycol and a dehydration condensation reaction can be used.

Here, the aromatic ester oligomer is preferably a polyester oligomer obtained by synthesis of an aromatic dicarboxylic acid, which is a dicarboxylic acid, and a diol.
Hereinafter, the dicarboxylic acid and diol that can be preferably used for the synthesis of the aromatic ester oligomer in the present invention will be described.

-Dicarboxylic acid-
As the dicarboxylic acid, either an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid can be used.
Examples of the aromatic dicarboxylic acid include phthalic acid, terephthalic acid, and isophthalic acid. Among these, phthalic acid and terephthalic acid are preferable, from the viewpoint of improving pencil hardness when a hard coat layer is provided, improving display unevenness when incorporated in a liquid crystal display device, and improving polarizer durability. Phthalic acid is particularly preferred. Two or more aromatic dicarboxylic acids may be used in combination. Specifically, combined use of phthalic acid and terephthalic acid can be mentioned. Among aromatic ester oligomers, it is possible to improve the pencil hardness when a hard coat layer is provided, to improve display unevenness when incorporated in a liquid crystal display device, and to improve the durability of a polarizer. Among them, it is preferable to increase the ratio of phthalic acid. Among the repeating units derived from dicarboxylic acid contained in the aromatic ester oligomer, the ratio of the repeating units derived from phthalic acid is preferably 70 mol% or more, and 80 mol% or more. More preferably, it is 90 mol% or more. The ratio (molar ratio) of phthalic acid to terephthalic acid is preferably 5: 5 to 10: 0, and preferably 7: 3 to 10: 0, from the viewpoint of reducing Rth of the cellulose acylate film. Is more preferable, and 10: 0 is particularly preferable.
Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, suberic acid, azelaic acid, cyclohexanedicarboxylic acid, and sebacic acid. Of these, succinic acid and adipic acid are preferable, and adipic acid is particularly preferable.
The carbon number of the dicarboxylic acid used in the present invention is preferably 4-10, and more preferably 4-8. In the present invention, a mixture of two or more kinds of dicarboxylic acids may be used. In this case, the average carbon number of the two or more kinds of dicarboxylic acids is preferably within the above range. If the carbon number of the dicarboxylic acid is within the above range, it is preferable because the compatibility with the cellulose acylate is excellent and bleed-out hardly occurs even when the cellulose acylate film is formed and heated.
An aliphatic dicarboxylic acid and an aromatic dicarboxylic acid may be used in combination. Specific examples include a combination of adipic acid and phthalic acid, a combination of adipic acid and terephthalic acid, a combination of succinic acid and phthalic acid, and a combination of succinic acid and terephthalic acid.
When the aliphatic dicarboxylic acid and the aromatic dicarboxylic acid are used in combination, the ratio (molar ratio) between them is m for the repeating unit derived from the aliphatic dicarboxylic acid, and n for the repeating unit derived from the aromatic dicarboxylic acid. M: n is 0:10 to 3: 7, more preferably 0:10 to 2: 8.

-Diol-
Examples of the diol include aliphatic diols and aromatic diols, with aliphatic diols being preferred.
Examples of the aliphatic diol include alkyl diols and alicyclic diols, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3- Butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2- Diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1, 5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2, , 4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, diethylene glycol, etc. Is mentioned.
Preferred aliphatic diols are at least one of ethylene glycol, 1,2-propanediol, and 1,3-propanediol, and particularly preferably at least one of ethylene glycol and 1,2-propanediol. Of these, ethylene glycol is particularly preferred from the viewpoint of compatibility with cellulose. When two types are used, it is preferable to use ethylene glycol and 1,2-propanediol.
The number of carbon atoms of the glycol is preferably 2 to 10, more preferably 2 to 6, and particularly preferably 2 to 4. When using 2 or more types of glycols, it is preferable that the average number of carbons of 2 or more types falls in the above range. If the number of carbon atoms of the glycol is in the above range, it is preferable because the compatibility with the cellulose acylate is excellent, and bleed-out hardly occurs even when the cellulose acylate film is formed and heated.

-Sealing-
Although both ends of the aromatic ester oligomer used in the present invention may be sealed or unsealed, the aromatic ester oligomer is particularly preferably sealed at the end with an alkyl group or an aromatic group. This is due to the fact that protecting the terminal with a hydrophobic functional group is effective in improving the polarizer durability of the polarizing plate and shows a role of delaying hydrolysis of the ester group.
It is preferable to protect with a monoalcohol residue or a monocarboxylic acid residue so that both ends of the aromatic ester oligomer do not become carboxylic acid or OH group. The hydroxyl value of the aromatic ester oligomer is preferably 10 mgKOH / g or less from the viewpoint of improving the polarizer durability, more preferably 5 mgKOH / g or less, and particularly preferably 0 mgKOH / g.
When both ends of the aromatic ester oligomer are sealed, it is preferable to seal by reacting with a monocarboxylic acid. At this time, both ends of the aromatic ester oligomer are monocarboxylic acid residues. Here, the residue is a partial structure of the aromatic ester oligomer and represents a partial structure having the characteristics of the monomer forming the aromatic ester oligomer. For example, the monocarboxylic acid residue formed from monocarboxylic acid R—COOH is R—CO—. An aliphatic monocarboxylic acid residue is preferred, the monocarboxylic acid residue is more preferably an aliphatic monocarboxylic acid residue having 2 to 22 carbon atoms, and an aliphatic monocarboxylic acid residue having 2 to 3 carbon atoms is more preferred. It is more preferably a group, and particularly preferably an aliphatic monocarboxylic acid residue having 2 carbon atoms.
When the carbon number of the monocarboxylic acid residue at both ends of the aromatic ester oligomer is 3 or less, the volatility decreases, the weight loss due to heating of the aromatic ester oligomer does not increase, and the occurrence of process contamination Occurrence of planar faults can be reduced. That is, as the monocarboxylic acids used for sealing, aliphatic monocarboxylic acids are preferable to aromatic carboxylic acids from the viewpoint of production suitability and surface quality. More preferably, the monocarboxylic acid is an aliphatic monocarboxylic acid having 2 to 22 carbon atoms, more preferably an aliphatic monocarboxylic acid having 2 to 3 carbon atoms, and an aliphatic monocarboxylic acid residue having 2 carbon atoms. Particularly preferred is a group. For example, acetic acid, propionic acid, butanoic acid and derivatives thereof are preferable, acetic acid or propionic acid is more preferable, and acetic acid (terminal is an acetyl group) is most preferable. Two or more monocarboxylic acids used for sealing may be mixed.
When both ends are sealed, a cellulose acylate film having a solid state at a normal temperature is difficult to handle, the humidity is stable, and the polarizer has excellent polarizer durability.

-Synthesis method-
The aromatic ester oligomer is synthesized by a polyesterification reaction or transesterification between the dicarboxylic acid containing the aromatic dicarboxylic acid, a diol, and a monocarboxylic acid or monoalcohol for end-capping, if necessary. It can be easily synthesized by either a hot melt condensation method by reaction or an interfacial condensation method of acid chlorides of these acids and glycols.

-Addition amount-
In the cellulose acylate film disposed on the surface A side of the polarizer, the content of the aromatic ester oligomer is preferably 5% by mass to 25% by mass with respect to the cellulose acylate, and 5-20 It is more preferable that it is mass%, and it is especially preferable that it is 5-15 mass%.

(Compound represented by formula (1) or (2))
The cellulose acylate film disposed on the surface A side of the polarizer further has a molecular weight / aromatic number ratio of 300 or less and a compound represented by the general formula (1) or (2) described later It is preferable from a viewpoint of improving polarizer durability. These compounds are also preferably used from the viewpoint of realizing a pencil hardness of 3H when a hard coat layer is provided. In the following, the compound represented by the general formula (1) or (2) may be referred to as a polarizer durability improver.
The polarizer durability improving agent preferably has a hydrogen bonding hydrogen donating group.

Examples of hydrogen bonding hydrogen donating groups are described, for example, in Jeffrey, George A., et al. It is described in a book such as Introduction to Hydrogen Bonding published by Oxford UP.
In the present invention, the hydrogen bondable hydrogen donating group in the polarizer durability improving agent includes amino group, acylamino group, alkoxycarbonylamino group, aryloxycarbonyl from the viewpoint of interaction with carbonyl group in cellulose acylate. An amino group, a sulfonylamino group, a hydroxy group, a mercapto group, and a carboxyl group are preferable, a sulfonylamino group, an acylamino group, an amino group, and a hydroxyl group are more preferable, and an amino group and a hydroxyl group are still more preferable.

The ratio of molecular weight / aromatic ring number in the polarizer durability improver is 300 or less, preferably 190 or less, more preferably 160 or less, and particularly preferably 150 or less.
The ratio of molecular weight / aromatic ring number in the polarizer durability improving agent is preferably 90 or more, and more preferably 100 or more, from the viewpoint of improving compatibility with cellulose acylate.

The molecular weight of the polarizer durability improving agent is preferably 200 to 1000, more preferably 250 to 800, and particularly preferably 280 to 600. When the molecular weight is equal to or higher than the lower limit of the above range, disappearance due to the volatilization of the polarizer durability improving agent during film formation of the cellulose acylate film can be suppressed, and when the molecular weight is equal to or lower than the upper limit of the above range, This is preferable because a cellulose acylate film having good compatibility between the cellulose acylate disposed on the surface A side and the polarizer durability improving agent and having a low haze can be obtained.
Hereinafter, the polarizer durability improving agent will be described in the order of the compound represented by the general formula (1) and the compound represented by the general formula (2).

-Compound represented by the general formula (1)-

In General Formula (1), R ¹ represents a substituent, R ² represents a substituent represented by the following General Formula (1-2); n1 represents an integer of 0 to 4, and n1 is 2 or more. A plurality of R ¹ may be the same or different from each other; n2 represents an integer of 1 to 5, and when n2 is 2 or more, a plurality of R ² may be the same or different from each other. Also good.

In general formula (1-2), A represents a substituted or unsubstituted aromatic ring; R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or the following general formula: Represents a substituent represented by (1-3); R ⁵ represents a single bond or an alkylene group having 1 to 5 carbon atoms; X represents a substituted or unsubstituted aromatic ring; and n3 represents 0. Represents an integer of -10, and when n3 is 2 or more, the plurality of R ⁵ and X may be the same or different from each other.

In General Formula (1-3), X represents a substituted or unsubstituted aromatic ring; R ⁶ , R ⁷ , R ⁸ , and R ⁹ are each independently a hydrogen atom or a C 1-5 carbon atom. N5 represents an integer of 1 to 11, and when n5 is 2 or more, a plurality of R ⁶ , R ⁷ , R ⁸ , R ⁹ and X may be the same or different.

R ¹ represents a substituent. Examples of the substituent are not particularly limited, and may be an alkyl group (preferably an alkyl group having 1 to 10 carbon atoms such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2 -Ethoxyethyl, 1-carboxymethyl, etc.), alkenyl groups (preferably alkenyl groups having 2-20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl groups (preferably alkynyl groups having 2-20 carbon atoms). , For example, ethynyl, butadiynyl, phenylethynyl, etc.), a cycloalkyl group (preferably a cycloalkyl group having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), an aryl group (preferably An aryl group having 6 to 26 carbon atoms, such as phenyl, -Naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl and the like), a heterocyclic group (preferably a heterocyclic group having 2 to 20 carbon atoms, such as 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, etc.), an alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, such as methoxy, ethoxy, isopropyloxy, benzyloxy, etc.), an aryloxy group (preferably carbon An aryloxy group having 6 to 26 atoms such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc., an alkoxycarbonyl group (preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, such as Ethoxycarbonyl, 2-ethylhexyloxycar Nyl, etc.), an amino group (preferably an amino group having 0 to 20 carbon atoms, such as amino, N, N-dimethylamino, N, N-diethylamino, N-ethylamino, anilino, etc.), a sulfonamide group (preferably Is a sulfonamide group having 0 to 20 carbon atoms, such as N, N-dimethylsulfonamide, N-phenylsulfonamide, etc., an acyloxy group (preferably an acyloxy group having 1 to 20 carbon atoms, such as acetyloxy, Benzoyloxy and the like), a carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, such as N, N-dimethylcarbamoyl, N-phenylcarbamoyl and the like), an acylamino group (preferably an acylamino group having 1 to 20 carbon atoms) For example, acetylamino, benzoylamino, etc.), cyano group, or halogen atom (For example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.) and a hydroxyl group are mentioned.

R ¹ is preferably an alkyl group having 1 to 20 carbon atoms and a hydroxyl group, more preferably a hydroxyl group and a methyl group. R ¹ may further have one or more substituents, and examples of the further substituent include the same substituents as R ¹ .

  n1 represents the integer of 0-4, and 2-4 are preferable.

  n2 represents the integer of 1-5, 1-3 are preferable and 1-2 are more preferable.

R ² represents a substituent represented by the following general formula (1-2).

In general formula (1-2), A represents a substituted or unsubstituted aromatic ring; R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or the following general formula: Represents a substituent represented by (1-3); R ⁵ represents a single bond or an alkylene group having 1 to 5 carbon atoms; X represents a substituted or unsubstituted aromatic ring; and n3 represents 0. Represents an integer of -10, and when n3 is 2 or more, the plurality of R ⁵ and X may be the same or different from each other.

A represents a substituted or unsubstituted aromatic ring. The aromatic ring may be a heterocyclic ring containing a hetero atom such as a nitrogen atom, an oxygen atom, or a sulfur atom. Examples of A include benzene ring, indene ring, naphthalene ring, fluorene ring, phenanthrene ring, anthracene ring, biphenyl ring, pyrene ring, pyran ring, dioxane ring, dithiane ring, thiyne ring, pyridine ring, piperidine ring, oxazine ring Morpholine ring, thiazine ring, pyridazine ring, pyrimidine ring, pyrazine ring, piperazine ring, triazine ring and the like. Further, other 6-membered rings or 5-membered rings may be condensed.
A is preferably a benzene ring.
Examples of the substituent that A may have include a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), an alkyl group, a hydroxyl group, and the like. An alkyl group or a hydroxyl group is preferable, and carbon A C1-C10 alkyl group or a hydroxyl group is more preferable, and a C1-C5 alkyl group or a hydroxyl group is still more preferable.

In General Formula (1-2), R ⁵ represents a single bond or an alkylene group having 1 to 5 carbon atoms, and the alkylene group having 1 to 5 carbon atoms may have a substituent. R ⁵ is preferably an alkylene group having 1 to 4 carbon atoms, and more preferably an alkylene group having 1 to 3 carbon atoms. Examples of the substituent that R ⁵ may have include an alkyl group having 1 to 5 carbon atoms (eg, methyl, ethyl, isopropyl, t-butyl), a halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine). Atoms), hydroxyl groups and the like.

  In general formula (1-2), X represents a substituted or unsubstituted aromatic ring. The aromatic ring may be a heterocyclic ring containing a hetero atom such as a nitrogen atom, an oxygen atom, or a sulfur atom. Examples of X include benzene ring, indene ring, naphthalene ring, fluorene ring, phenanthrene ring, anthracene ring, biphenyl ring, pyrene ring, pyran ring, dioxane ring, dithiane ring, thiyne ring, pyridine ring, piperidine ring, oxazine ring Morpholine ring, thiazine ring, pyridazine ring, pyrimidine ring, pyrazine ring, piperazine ring, triazine ring and the like. Further, other 6-membered rings or 5-membered rings may be condensed. X is preferably a benzene ring. Examples of the substituent which X may have are the same as the examples given as the substituent of A.

n3 represents the integer of 0-10, 0-2 are preferable and 0-1 are more preferable. When n3 is an integer of 2 or more, a plurality of groups represented by — (R ⁵ —X) may be the same as or different from each other, and each bond to A. When n3 is 0, a group represented by — (R ⁵ —X) does not exist, and thus a group represented by — (R ⁵ —X) is not bonded to A.

R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms and a substituent represented by the following general formula (1-3). R ³ and R ⁴ are preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a substituent represented by the general formula (1-3), and a hydrogen atom, a methyl group, or a general formula (1-3) The substituent represented is more preferred.

In the substituent represented by the general formula (1-3) that may be contained in the substituent represented by the general formula (1-2), X represents a substituted or unsubstituted aromatic ring. Each of R ⁶ , R ⁷ , R ⁸ and R ⁹ independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; n5 represents an integer of 1 to 11 and when n5 is 2 or more; A plurality of R ⁶ , R ⁷ , R ⁸ , R ⁹ and X may be the same or different from each other.

X in the substituent represented by the general formula (1-3) which may be contained in the substituent represented by the general formula (1-2) is the same as in the general formula (1-2). It is synonymous with X, and its preferable range is also the same.
R ⁶ , R ⁷ , R ⁸ , and R ⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ³ and R ⁴ are preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group.

  n5 represents an integer of 1 to 11, preferably 1 to 9, and more preferably 1 to 7.

  The substituent represented by the general formula (1-3) that may be contained in the substituent represented by the general formula (1-2) is represented by the following general formula (1-3 ′). A substituent is preferred.

  The definition of each symbol of the general formula (1-3 ′) that may be included in the substituent represented by the general formula (1-2) is the same as that in the general formula (1-3). The preferred range is also the same.

  The substituent represented by the general formula (1-3) that may be contained in the substituent represented by the general formula (1-2) is represented by the following general formula (1-3 ″). It is more preferable that it is a substituent.

  In general formula (1-3 ″), n4 represents an integer of 0 to 10.

  n4 represents the integer of 0-10, 0-8 are preferable and 0-6 are more preferable.

  The substituent represented by the general formula (1-2) is preferably a substituent represented by the following general formula (1-2 ').

In general formula (1-2 ′), R ³ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a substituent represented by general formula (1-3); R ⁵ represents a single bond. Or an alkylene group having 1 to 5 carbon atoms; X represents a substituted or unsubstituted aromatic ring; n3 represents an integer of 0 to ^5, and when n3 is 2 or more, a plurality of R ⁵ and X May be the same as or different from each other.

  The preferred range of each symbol in the general formula (1-2 ') is the same as that in the general formula (1-2).

  The general formula (1-2) is preferably represented by the following general formula (1-2 ″).

In general formula (1-2 ″), n3 represents an integer of 0 to 5.
The preferable range of n3 in the general formula (1-2 ″) is the same as the preferable range of n3 in the general formula (1-2).

  Although the specific example of a compound represented by General formula (1) below is shown, it is not limited to the following specific examples.

  In addition, in order to enable the compound represented by the general formula (1) having a different number of hydroxyl groups to be hydrogen-bonded at multiple points, it contains two or more different compounds represented by the general formula (1). It is good also as a mixture. One example is a styrenated phenol in which 1 to 3 moles of styrene are alkylated with respect to phenol, a styrenated phenol in which styrene is further alkylated at the phenyl moiety of the alkylated styrene, and an oligomer of about 2 to 4 mers of styrene. Mention may be made of mixtures with styrenated phenols alkylated to phenol.

The compound represented by the general formula (1) can generally be synthesized by adding 1 equivalent or more of styrenes in the presence of an acid catalyst to 1 equivalent of phenols, and a commercially available product may be used. . Moreover, you may use the mixture obtained by the said synthesis method as it is.
As a commercial item of the compound represented by the general formula (1), “TSP” which is a styrenated phenol manufactured by Sanko Co., Ltd., “PH-25” manufactured by Nikko Paint Chemical Co., Ltd., “manufactured by Seiko Chemical Co., Ltd.” Non-flex WS "etc. are mentioned.

（一般式（２）中、Ｒ¹¹、Ｒ¹³及びＲ¹⁵は、各々独立に、水素原子、炭素数１〜２０のアルキル基、炭素数３〜２０のシクロアルキル基、炭素数２〜２０のアルケニル基または炭素数６〜２０の芳香族基を表す。） -Compound represented by the general formula (2)-

(In the general formula (2), R ¹¹ , R ¹³ and R ¹⁵ are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an alkyl group having 2 to 20 carbon atoms. Represents an alkenyl group or an aromatic group having 6 to 20 carbon atoms.)

In the general formula (2), R ¹⁵ preferably represents an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aromatic group having 6 to 20 carbon atoms, and 1 to 12 carbon atoms. It is more preferable that it is a C3-C12 cycloalkyl group or a C6-C18 aromatic group, and a C1-C6 alkyl group and a C3-C6 cycloalkyl group are also included. Or an aromatic group having 6 to 12 carbon atoms, more preferably a methyl group, an ethyl group, an isopropyl group, a cyclohexyl group or a phenyl group, and a methyl group, an isopropyl group or a phenyl group. Most preferred.

In general formula (2), R ¹¹ and R ¹³ are each independently preferably a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aromatic group having 6 to 20 carbon atoms. It is more preferably an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and a carbon atom having 3 to 6 carbon atoms. It is particularly preferably a cycloalkyl group or a phenyl group, more preferably a hydrogen atom, a methyl group, an ethyl group, a cyclohexyl group or a phenyl group, and most preferably a methyl group or a phenyl group.
In General Formula (2), R ¹¹ is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aromatic group having 6 to 20 carbon atoms, and R ¹³ is a hydrogen atom. Or it is preferable that it is a C6-C20 aromatic group. R ¹¹ is an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aromatic group having 6 to 12 carbon atoms, and R ¹³ is a hydrogen atom or an aromatic group having 6 to 12 carbon atoms. More preferably, it is a group. It is particularly preferable that R ¹¹ is an alkyl group having 1 to 3 carbon atoms or a cyclohexyl group, and R ¹³ is a hydrogen atom or a phenyl group. It is more particularly preferable that R ¹¹ is a methyl group and R ¹³ is a hydrogen atom or a phenyl group.

R ¹⁵ may further have a substituent. The substituent that R ¹⁵ may have is not particularly limited as long as it is not contrary to the gist of the present invention, but is preferably a halogen atom, an alkyl group, or an aromatic group, and preferably a halogen atom, a carbon number It is more preferably an alkyl group having 1 to 6 carbon atoms or an aromatic group having 6 to 12 carbon atoms, and particularly preferably a chlorine atom, a methyl group, or a phenyl group. In particular, when R ¹⁵ is an alkyl group having 1 to 20 carbon atoms, it preferably has an aromatic group as a substituent, more preferably an aromatic group having 6 to 12 carbon atoms, and a phenyl group. Is particularly preferred. In particular, when R ¹⁵ is an aromatic group having 1 to 20 carbon atoms, it preferably has a halogen atom or an alkyl group having 1 to 20 carbon atoms as a substituent, and a halogen atom or an alkyl group having 1 to 6 carbon atoms. It is more preferable to have a group, and it is particularly preferable to have a chlorine atom or a methyl group.

R ¹¹ and R ¹³ may further have a substituent. The substituent that R ¹¹ may have is not particularly limited as long as it does not contradict the gist of the present invention, but is preferably an aromatic group having 6 to 12 carbon atoms, and is preferably a phenyl group. More preferred.

  Although the specific example of a compound represented by General formula (2) below is shown, it is not limited to the following specific examples.

  The compound represented by the general formula (2) may be obtained commercially or synthesized by a known method.

-Content-
The cellulose acylate film disposed on the surface A side of the polarizer has a ratio of the molecular weight / aromatic number of 300 or less, and contains the compound represented by the general formula (1) or (2) The amount is preferably 0.5% by mass to 20% by mass and more preferably 1% by mass to 20% by mass with respect to the cellulose acylate. If it is 1% by mass or more with respect to the cellulose acylate disposed on the surface A side of the polarizer, an effect of improving the elastic modulus is easily obtained, and if it is 20% by mass or less with respect to the cellulose acylate, cellulose is obtained. When an acylate film is formed, bleeding out and bleeding are less likely to occur.
The ratio of the molecular weight / aromatic number is 300 or less, and the content of the compound represented by the general formula (1) or (2) is 1 to 15% by mass with respect to the cellulose acylate. Is particularly preferable, and it is more preferably 1 to 10% by mass.

(UV absorber)
The cellulose acylate film disposed on the surface A side of the polarizer used in the present invention preferably contains a UV absorber together with the main component cellulose acylate. The UV absorber contributes to improvement of polarizer durability. In particular, in the embodiment in which the cellulose acylate film of the polarizing plate of the present invention is used as a surface protective film of a polarizing plate disposed on the viewing side of an image display device, the addition of a UV absorber is effective.

  There is no restriction | limiting in particular about UV absorber which can be used for this invention. Any of the UV absorbers conventionally used for cellulose acylate can be used. Examples of the ultraviolet absorber include compounds described in JP-A No. 2006-184874. Polymer ultraviolet absorbers can also be preferably used. In particular, polymer type ultraviolet absorbers described in JP-A-6-148430 are preferably used.

The amount of the UV absorber used is not uniform depending on the type of UV absorber, usage conditions, etc., but the UV absorber is contained in a proportion of 1 to 3% by mass with respect to the cellulose acylate as the main component. More preferably.
Examples include ultraviolet absorbers having the following structure, but the ultraviolet absorbers to be added are not limited to these.

(Other additives)
The said cellulose acylate film arrange | positioned at the surface A side of a polarizer may further contain at least 1 sort (s) of another additive in the range which does not impair the effect of this invention. Examples of other additives include plasticizers other than aromatic ester oligomers (for example, phosphate ester plasticizers, carboxylic ester plasticizers, polycondensation oligomer plasticizers, etc.), retardation humidity durability improvers, Antioxidants and the like are included.

-Retardation humidity durability improver-
As a compound which improves retardation humidity durability, the following compounds can be mentioned as a specific example, for example.

-Compound having a hydroxyl group-
Examples of the compound containing a hydroxyl group preferably used in the present invention, more preferably a compound containing a phenolic hydroxyl group, include, for example, Compound A described in pages 13 to 19 of JP-A-2008-89860, and JP-A A compound represented by the general formula (I) described on pages 7 to 9 of 2008-233530 can be preferably used.

（一般式（１）中、Ｒａはアルキル基、アルケニル基、アルキニル基、複素環基又はアリール基を表す。Ｘ¹、Ｘ²、Ｘ³及びＸ⁴はそれぞれ独立に単結合又は２価の連結基を表す。Ｒ¹、Ｒ²、Ｒ³及びＲ⁴はそれぞれ独立に水素原子、アルキル基、アルケニル基、アルキニル基、アリール基、アシル基又は複素環基を表す。）

（一般式（４）中、Ｒｂ及びＲｃはそれぞれ独立にアルキル基、アルケニル基、アルキニル基、複素環基又はアリール基を表す。Ｘ⁵及びＸ⁶はそれぞれ独立に単結合又は２価の連結基を表す。Ｒ⁵及びＲ⁶はそれぞれ独立に水素原子、アルキル基、アルケニル基、アルキニル基、アリール基、アシル基又は複素環基を表す。）
前記、Ｘ¹〜Ｘ⁶は、単結合又は２価の連結基を表し、それぞれ同じであっても異なっていてもよく、２価の連結基としては、下記一般式（５）で表される群の中から選ばれることが好ましい。

(Compound having an amino group)
Although it does not specifically limit as a compound containing the amino group preferably used by this invention, It is preferable that it is a compound represented by the following general formula (3) or (4).

(In the general formula (1), Ra represents an alkyl group, an alkenyl group, an alkynyl group, a heterocyclic group or an aryl group. X ¹ , X ² , X ³ and X ⁴ are each independently a single bond or a divalent linkage. R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an acyl group or a heterocyclic group.

(In General Formula (4), Rb and Rc each independently represents an alkyl group, an alkenyl group, an alkynyl group, a heterocyclic group or an aryl group. X ⁵ and X ⁶ each independently represent a single bond or a divalent linking group. R ⁵ and R ⁶ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an acyl group or a heterocyclic group.
X ^{1 to} X ⁶ represent a single bond or a divalent linking group, and may be the same or different from each other, and the divalent linking group is represented by the following general formula (5). It is preferable to be selected from the group.

一般式（６）中、Ｙはメチン基又は窒素原子を表す。Ｑａ、Ｑｂ及びＱｃはそれぞれ独立に単結合又は２価の連結基を表す。Ｒａ、Ｒｂ、及びＲｃはそれぞれ独立に水素原子、置換若しくは無置換のアルキル基、置換若しくは無置換のアルケニル基、置換若しくは無置換のアルキニル基、置換若しくは無置換のアリール基、シアノ基、ハロゲン原子、置換若しくは無置換の複素環基、又は、−Ｎ（Ｒｄ）（Ｒｄ’）を表し、Ｒｄ及びＲｄ’はそれぞれ独立に水素原子又は置換基を表し、Ｒｄ及びＲｄ’は互いに連結して環を形成してもよい。ＲａとＲｂは互いに連結して環を形成してもよい。Ｘ１は単結合又は下記２価の連結基群（Ｌ）から選択される２価の連結基を表す。Ｘ２は単結合又は２価の連結基を表す。Ｒ¹及びＲ²はそれぞれ独立に水素原子、置換若しくは無置換のアルキル基、置換若しくは無置換のアルケニル基、置換若しくは無置換のアルキニル基、置換若しくは無置換のアリール基、又は、置換若しくは無置換の複素環基を表し、Ｒ¹とＲ²は互いに連結して環を形成してもよい。

（各式中、＊側が前記一般式（６）で表される化合物中の含窒素芳香環に置換している窒素原子との連結部位であり、Ｒｇは置換若しくは無置換のアルキル基、置換若しくは無置換のアルケニル基、置換若しくは無置換のアルキニル基、置換若しくは無置換のアリール基、又は、置換若しくは無置換の複素環基を表す。） The compound having an amino group is preferably a compound represented by the following general formula (6) having a pyridine or pyrimidine mother nucleus and having an amino group as a substituent at any substitutable position. Is also preferable.

In general formula (6), Y represents a methine group or a nitrogen atom. Qa, Qb and Qc each independently represent a single bond or a divalent linking group. Ra, Rb and Rc are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, a cyano group, or a halogen atom. Represents a substituted or unsubstituted heterocyclic group, or —N (Rd) (Rd ′), Rd and Rd ′ each independently represent a hydrogen atom or a substituent, and Rd and Rd ′ are linked to each other to form a ring; May be formed. Ra and Rb may be connected to each other to form a ring. X1 represents a single bond or a divalent linking group selected from the following divalent linking group group (L). X2 represents a single bond or a divalent linking group. R ¹ and R ² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, or substituted or unsubstituted And R ¹ and R ² may be linked to each other to form a ring.

(In each formula, the * side is a linking site with a nitrogen atom substituted on the nitrogen-containing aromatic ring in the compound represented by the general formula (6), and Rg is a substituted or unsubstituted alkyl group, substituted or Represents an unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group.)

-Antioxidant-
In the present invention, known antioxidants for cellulose acylate solutions such as 2,6-di-tert-butyl-4-methylphenol, 4,4′-thiobis- (6-tert-butyl-3-methylphenol) ), 1,1′-bis (4-hydroxyphenyl) cyclohexane, 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 2,5-di-tert-butylhydroquinone, pentaerythrityl-tetrakis A phenolic or hydroquinone antioxidant such as [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] can be added. Further, tris (4-methoxy-3,5-diphenyl) phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, bis (2,6-di-tert) It is preferable to add a phosphorus-based antioxidant such as -butyl-4-methylphenyl) pentaerythritol diphosphite and bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite. The addition amount of the antioxidant is preferably 0.05 to 5.0 parts by mass with respect to 100 parts by mass of the cellulose resin.

(Method for producing a cellulose acylate film disposed on the surface A side of the polarizer)
There is no restriction | limiting in particular in the method of manufacturing the said cellulose acylate film arrange | positioned at the surface A side of a polarizer, It can form into a film using a well-known method. For example, the film may be formed using either a solution casting film forming method or a melt film forming method. From the viewpoint of improving the surface shape of the film, the cellulose acylate film is preferably produced using a solution casting film forming method. Hereinafter, although the case where the solution casting film forming method is used will be described as an example, the present invention is not limited to the solution casting film forming method. In addition, about the case where a melt film forming method is used, a well-known method can be used.

-Polymer solution-
In the solution casting film forming method, a web is formed by using the cellulose acylate, the aromatic ester oligomer, and a polymer solution (cellulose acylate solution) containing various additives as required. Hereinafter, a polymer solution (hereinafter also referred to as a cellulose acylate solution as appropriate) that can be used in the solution casting film forming method will be described.

-Solvent-
The cellulose acylate used in the present invention is dissolved in a solvent to form a dope, which is cast on a substrate to form a film. At this time, since it is necessary to evaporate the solvent after extrusion or casting, it is preferable to use a volatile solvent.
Furthermore, it does not react with a reactive metal compound or a catalyst, and does not dissolve the casting base material. Two or more solvents may be mixed and used.
Alternatively, cellulose acylate and a reactive metal compound capable of hydrolysis polycondensation may be dissolved in different solvents and then mixed.
Here, an organic solvent having good solubility in the cellulose acylate is referred to as a good solvent, and has a main effect on dissolution, and an organic solvent used in a large amount among them is a main (organic) solvent or a main solvent ( Organic) solvent.

  Examples of the good solvent include ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethers such as tetrahydrofuran (THF), 1,4-dioxane, 1,3-dioxolane, 1,2-dimethoxyethane, and the like. In addition to esters such as methyl acid, ethyl formate, methyl acetate, ethyl acetate, amyl acetate, γ-butyrolactone, methyl cellosolve, dimethylimidazolinone, dimethylformamide, dimethylacetamide, acetonitrile, dimethylsulfoxide, sulfolane, nitroethane, Examples include methylene chloride and methyl acetoacetate, and 1,3-dioxolane, THF, methyl ethyl ketone, acetone, methyl acetate and methylene chloride are preferred.

The dope preferably contains 1 to 40% by mass of an alcohol having 1 to 4 carbon atoms in addition to the organic solvent.
After casting the dope on the metal support, the solvent starts to evaporate and the ratio of alcohol increases so that the web (referred to as the dope film after casting the cellulose acylate dope on the support) Used as a gelling solvent that makes it easy to gel and peel off from the metal support, or when these ratios are small, promote the dissolution of cellulose acylate, a non-chlorine organic solvent There is also a role to suppress gelation, precipitation, and viscosity increase of the reactive metal compound.

Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol, and propylene glycol monomethyl ether.
Of these, methanol and ethanol are preferred because they are excellent in dope stability, have a relatively low boiling point, good drying properties, and no toxicity. Ethanol is most preferred. These organic solvents alone are not soluble in cellulose acylate and are referred to as poor solvents.

In the present invention, cellulose acylate which is a raw material of cellulose acylate contains hydrogen bonding functional groups such as hydroxyl groups, esters, and ketones, and therefore 5 to 30% by mass, more preferably 7 to 25% by mass in the total solvent. More preferably, it contains 10 to 20% by mass of alcohol from the viewpoint of reducing the peeling load from the casting support.
Further, in the present invention, it is effective to contain a small amount of water to increase the solution viscosity and the film strength in the wet film state at the time of drying, or to increase the dope strength at the time of casting the drum method. It may be contained in an amount of 0.1 to 5% by mass, more preferably 0.1 to 3% by mass, and particularly 0.2 to 2% by mass.

  Examples of combinations of organic solvents preferably used as the solvent for the polymer solution in the present invention are described in JP-A-2009-262551.

  In addition, if necessary, a non-halogen organic solvent can be used as a main solvent, and detailed description can be found in the Japan Institute of Invention Publication (Publication No. 2001-1745, published on March 15, 2001, Invention Association). There is a description.

The cellulose acylate concentration in the polymer solution in the present invention is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and most preferably 15 to 30% by mass.
The cellulose acylate concentration can be adjusted to a predetermined concentration at the stage of dissolving the cellulose acylate in a solvent. Further, after preparing a low concentration (for example, 4 to 14% by mass) solution in advance, the solution may be concentrated by evaporating the solvent. Furthermore, after preparing a high concentration solution in advance, it may be diluted. Moreover, the density | concentration of a cellulose acylate can also be reduced by adding an additive.

  The timing of adding the additive can be appropriately determined according to the type of the additive. For example, aromatic ester oligomers and UV absorbers can be doped after dissolving UV absorbers in alcohols such as methanol, ethanol, butanol, organic solvents such as methylene chloride, methyl acetate, acetone, dioxolane, or mixed solvents thereof. It may be added or added directly during the dope composition. For an inorganic powder that does not dissolve in an organic solvent, a dissolver or a sand mill is used in the organic solvent and cellulose acylate to be dispersed and then added to the dope.

  The most preferable solvent that satisfies such conditions and dissolves cellulose acylate, which is a preferred polymer compound, at a high concentration is a mixed solvent having a ratio of methylene chloride: ethyl alcohol of 95: 5 to 80:20. Alternatively, a mixed solvent of methyl acetate: ethyl alcohol 60:40 to 95: 5 is also preferably used.

(1) Dissolution step A step of dissolving the cellulose acylate and additives in an organic solvent mainly containing a good solvent for cellulose acylate while stirring to form a dope, or an additive in a cellulose acylate solution This is a step of mixing a solution to form a dope.
For dissolving cellulose acylate, a method carried out at normal pressure, a method carried out below the boiling point of the main solvent, a method carried out under pressure above the boiling point of the main solvent, JP-A-9-95544, JP-A-9-95557 Alternatively, various dissolution methods such as a cooling dissolution method as described in JP-A-9-95538 and a high-pressure method as described in JP-A-11-21379 can be used. The method of pressurizing at a boiling point or higher is preferred.
The concentration of cellulose acylate in the dope is preferably 10 to 35% by mass. It is preferable that an additive is added to the dope during or after dissolution to dissolve and disperse, and then filtered through a filter medium, defoamed, and sent to the next step with a liquid feed pump.

(2) Casting process An endless metal belt that feeds the dope to a pressure die through a liquid feed pump (for example, a pressurized metering gear pump) and transfers it infinitely, such as a stainless steel belt, or a metal such as a rotating metal drum This is a step of casting the dope from the pressure die slit to the casting position on the support.
A pressure die that can adjust the slit shape of the die base and facilitates uniform film thickness is preferred. The pressure die includes a coat hanger die and a T die, and any of them is preferably used. The surface of the metal support is a mirror surface. In order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the dope amount may be divided and stacked. Or it is also preferable to obtain the film of a laminated structure by the co-casting method which casts several dope simultaneously.

(3) Solvent evaporation process The web (which is the state before becoming a finished product of cellulose acylate film and still containing a lot of solvent) is heated on the metal support, and the web is peeled off from the metal support. This is the process of evaporating the solvent until it becomes possible.
To evaporate the solvent, there are a method of blowing air from the web side and / or a method of transferring heat from the back side of the metal support by a liquid, a method of transferring heat from the front and back by radiant heat, etc. However, drying efficiency is preferable. A method of combining them is also preferable. In the case of backside liquid heat transfer, it is preferable to heat at or below the boiling point of the main solvent of the organic solvent used in the dope or the organic solvent having the lowest boiling point.

(4) Peeling process It is the process of peeling the web which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process. It should be noted that if the residual solvent amount of the web at the time of peeling (the following formula) is too large, it is difficult to peel, or conversely, if it is peeled off after being sufficiently dried on the metal support, a part of the web is in the middle. It may come off.
Here, there is a gel casting method (gel casting) as a method for increasing the film forming speed (the film forming speed can be increased by peeling while the residual solvent amount is as large as possible). For example, there are a method in which a poor solvent for cellulose acylate is added to the dope and the dope is cast and then gelled, a method in which the temperature of the metal support is lowered and gelled. By gelling on the metal support and increasing the strength of the film at the time of peeling, the speed of film formation can be increased by speeding up the peeling.
The amount of residual solvent during peeling of the web on the metal support is preferably within a range of 5 to 150% by mass depending on the strength of drying conditions, the length of the metal support, etc., but the amount of residual solvent is larger. In the case of peeling at the time, the amount of residual solvent at the time of peeling is determined in consideration of economic speed and quality. In the present invention, the temperature at the peeling position on the metal support is preferably -50 to 40 ° C, more preferably 10 to 40 ° C, and most preferably 15 to 30 ° C.

The residual solvent amount of the web at the peeling position is preferably 10 to 150% by mass, and more preferably 10 to 120% by mass.
The amount of residual solvent can be represented by the following formula.
Residual solvent amount (% by mass) = [(MN) / N] × 100
Here, M is the mass of the web at an arbitrary point in time, and N is the mass when the mass M is dried at 110 ° C. for 3 hours.

(5) Drying or heat treatment step, stretching step After the peeling step, a drying device that alternately conveys the web through a plurality of rolls arranged in the drying device, and / or a tenter that clips and conveys both ends of the web with clips. It is preferred to dry the web using an apparatus.

When heat treatment is performed in the present invention, the heat treatment temperature is less than Tg-5 ° C, preferably Tg-20 ° C or more and less than Tg-5 ° C, and preferably Tg-15 ° C or more and less than Tg-5 ° C. More preferred.
The heat treatment temperature is preferably 30 minutes or less, more preferably 20 minutes or less, and particularly preferably about 10 minutes.

  As a means for drying and heat treatment, hot air is generally blown on both sides of the web, but there is also a means for heating by applying a microwave instead of the wind. The temperature, air volume, and time vary depending on the solvent used, and the conditions may be appropriately selected according to the type and combination of the solvents used.

  The stretching process may be performed in one direction of MD and TD, or may be biaxially stretched in both directions. Biaxial stretching is preferred. Stretching may be performed in one stage or in multiple stages. The tensile elastic modulus is adjusted to the above range by adjusting the type of cellulose acylate to be used and the acyl substitution degree, selecting the type of additive, or adjusting the ratio thereof. Can do.

The stretching ratio in stretching in the film transport direction MD is preferably 0 to 20%, more preferably 0 to 15%, and particularly preferably 0 to 10%. The stretch ratio (elongation) of the web during the stretching can be achieved by the peripheral speed difference between the metal support speed and the stripping speed (stripping roll draw). For example, when an apparatus having two nip rolls is used, the film can be preferably stretched in the conveying direction (longitudinal direction) by increasing the rotational speed of the nip roll on the outlet side rather than the rotational speed of the nip roll on the inlet side. it can. By performing such stretching, the tensile modulus of MD can be adjusted.
Here, the “stretch ratio (%)” means that obtained by the following formula.
Stretch ratio (%) = 100 × {(Length after stretching) − (Length before stretching)} / Length before stretching

The stretching ratio in stretching in the direction TD perpendicular to the film conveying direction is preferably 0 to 30%, more preferably 1 to 20%, and particularly preferably 2 to 15%.
In addition, in this invention, it is preferable to extend | stretch using a tenter apparatus as a method of extending | stretching to the direction TD orthogonal to a film conveyance direction.

  In the case of biaxial stretching, a desired retardation value can be obtained by relaxing the length in the longitudinal direction, for example, 0.8 to 1.0 times. The draw ratio is set according to the target optical characteristics. When manufacturing the said cellulose acylate film, it can also be uniaxially stretched in the elongate direction.

  It is preferable for the temperature during stretching to be Tg or less because the tensile elastic modulus in the stretching direction increases. The stretching temperature is preferably Tg-50 ° C to Tg, and more preferably Tg-30 ° C to Tg-5 ° C. On the other hand, when stretched under the above temperature conditions, the tensile elastic modulus in the stretching direction increases, while the tensile elastic modulus in the direction orthogonal thereto tends to decrease. Therefore, in order to increase the tensile elastic modulus in both the MD and TD directions by stretching, it is preferable to perform stretching in both directions, that is, biaxial stretching in the above temperature range.

  In addition, you may dry after an extending process. When drying after the stretching step, the drying temperature, the amount of drying air and the drying time differ depending on the solvent used, and the drying conditions may be appropriately selected according to the type and combination of the solvents used. In the present invention, the drying temperature after the stretching step is preferably lower than the stretching temperature in the stretching step from the viewpoint of increasing the front contrast when the film is incorporated into a liquid crystal display device.

(6) Winding The length of the film obtained as described above is preferably wound at 100 to 10000 m per roll, more preferably 500 to 7000 m, and further preferably 1000 to 6000 m. . The width of the film is preferably 0.5 to 5.0 m, more preferably 1.0 to 3.0 m, and still more preferably 1.0 to 2.5 m. When winding, it is preferable to give knurling to at least one end, the knurling width is preferably 3 mm to 50 mm, more preferably 5 mm to 30 mm, and the height is preferably 0.5 to 500 μm, more preferably 1 to 200 μm. is there. This may be a single push or a double push.

  The web thus obtained can be wound up to obtain a cellulose acylate film.

(Layer structure)
The cellulose acylate film disposed on the surface A side of the polarizer used in the present invention may be a single layer film or may have a laminated structure of two or more layers. For example, a laminated structure composed of two layers of a core layer and an outer layer (sometimes referred to as a surface layer or a skin layer) or a laminated structure composed of three layers of an outer layer, a core layer, and an outer layer are also preferable. It is also preferable that the laminated structure be formed by co-casting.
When the cellulose acylate film disposed on the surface A side of the polarizer used in the present invention has a laminated structure of two or more layers, it is preferable to add a matting agent to the outer layer. As the matting agent, for example, those described in JP-A-2011-127045 can be used, and for example, silica particles having an average particle size of 20 nm can be used.

(Knoop hardness)
In the first aspect of the polarizing plate of the present invention, the cellulose acylate film disposed on the surface A side of the polarizer has a Knoop hardness of 240 N / mm ² or more. In the second aspect of the polarizing plate of the present invention, The cellulose acylate film preferably has a Knoop hardness of 240 N / mm ² or more.
The polarizing plate of the present invention is more preferably Knoop hardness of the cellulose acylate film disposed on the surface A side of the polarizer is 240~290N / mm ^2, to be 250~290N / mm ² particularly preferable.

In the 2nd aspect of the polarizing plate of this invention, Knoop hardness when a hard-coat layer is laminated | stacked on the said cellulose acylate film arrange | positioned at the surface A side of a polarizer is 265 N / mm < ² > or more, and this invention In the first aspect of the polarizing plate, the Knoop hardness when a hard coat layer is laminated on the cellulose acylate film is preferably 265 N / mm ² or more.
In the polarizing plate of the present invention, the Knoop hardness when a hard coat layer is laminated on the cellulose acylate film disposed on the surface A side of the polarizer is more preferably 270 N / mm ² or more, 270 to 330 N / Mm ² is particularly preferred.

(Thickness of cellulose acylate film arranged on the surface A side of the polarizer)
The thickness of the cellulose acylate film is preferably 35 μm or less, more preferably 15 to 35 μm, and particularly preferably 15 to 30 μm.

(Optical characteristics of cellulose acylate film disposed on the surface A side of the polarizer)
The cellulose acylate film disposed on the surface A side of the polarizer preferably satisfies the following formula (1) from the viewpoint of suppressing display unevenness when incorporated in a liquid crystal display device.
Formula (1) | Rth (590) | ≦ 50 nm
(In Formula (1), Rth (590) represents retardation in the film thickness direction at a wavelength of 590 nm.)
| Rth (590) | is preferably 30 nm or less, more preferably 20 nm or less, and particularly preferably 10 nm or less, that is, Rth is particularly preferably −10 to 10 nm.

The cellulose acylate film disposed on the surface A side of the polarizer preferably satisfies the following formula (2) from the viewpoint of further improving display unevenness when incorporated in a liquid crystal display device.
Formula (2) | Re (590) | ≦ 5 nm
(In formula (2), Re (590) represents retardation in the in-plane direction of the film at a wavelength of 590 nm.)
| Re (590) | is preferably 3 nm or less, more preferably 2 nm or less, and particularly preferably 1 nm or less.

  In this specification, Re (λ) and Rth (λ) represent in-plane retardation and retardation in the thickness direction at the wavelength λ, respectively. In the present specification, the wavelength λ is 590 nm unless otherwise specified. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH (manufactured by Oji Scientific Instruments). Rth (λ) is Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH) as the tilt axis (rotary axis) (in the absence of the slow axis, any direction in the film plane) Is measured in 6 points from the inclined direction in 10 degree steps from the normal direction to 50 degrees on one side with respect to the normal direction of the film. KOBRA 21ADH calculates based on the retardation value, the assumed average refractive index, and the input film thickness value. The retardation value is measured from any two directions with the slow axis as the tilt axis (rotation axis) (in the absence of the slow axis, the arbitrary direction in the film plane is the rotation axis), and the value Rth can also be calculated from the following formula (A) and formula (B) based on the assumed average refractive index and the input film thickness value. Here, as the assumed value of the average refractive index, values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. The average refractive index values of main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59). The KOBRA 21ADH calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

Here, Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction, nx, ny, and nz represent refractive indexes in respective principal axis directions of the refractive index ellipsoid, and d represents a film. Represents thickness.
Rth = ((nx + ny) / 2−nz) × d Formula (B)
At this time, an average refractive index n is required as a parameter, and a value measured by an Abbe refractometer (“Abbe refractometer 2-T” manufactured by Atago Co., Ltd.) was used.

<Functional layer>
The polarizing plate of the present invention preferably has a functional layer on at least one surface of the cellulose acylate film disposed on the surface A side of the polarizer. Examples of the functional layer include a pattern retardation layer for displaying 3D images, a hard coat layer, an antireflection layer, an antiglare layer, an antistatic layer, and an optically anisotropic layer. Each functional layer may be used alone or in combination. In particular, an embodiment in which a hard coat layer is provided on a pattern retardation layer for 3D video display is preferable.

<Pattern retardation layer>
The optically anisotropic layer described in Japanese Patent No. 4887436 can be used.

(Shape of the first area and the second area)
The cellulose acylate film disposed on the surface A side of the polarizer has a first retardation region (hereinafter also simply referred to as a first region) and a second retardation region (hereinafter simply referred to as a second region) having different birefringence. And an optically anisotropic layer (hereinafter also referred to as a pattern retardation) in which the first retardation region and the second retardation region are alternately patterned for each line. From the viewpoint of use for a 3D stereoscopic image display system, it is preferable that the first region and the second region have a strip shape in which the lengths of the short sides of the first region and the second region are approximately the same.

In the cellulose acylate film disposed on the surface A side of the polarizer, the slow axis of the first region and the slow axis of the second region are substantially perpendicular to each other when the 3D image display is performed. This is preferable from the viewpoint that the polarization state of the light passing through the one region and the second region can be changed from linearly polarized light to circularly polarized light, or from circularly polarized light to linearly polarized light.
In the cellulose acylate film disposed on the surface A side of the polarizer, the slow axis of the first region and the slow axis of the second region are orthogonal to each other when displaying a 3D image. It is more preferable from the viewpoint that the polarization state of the light that has passed through the first region and the second region can be changed from linearly polarized light to circularly polarized light, or from circularly polarized light to linearly polarized light without being elliptically polarized light.

  In the cellulose acylate film disposed on the surface A side of the polarizer, the direction of the long side of the pattern and the direction in which the sound speed of the support is maximized are substantially orthogonal, which results in a shift between the pattern region and the pixel. It is preferable from the viewpoint of reducing and suppressing crosstalk.

(Retardation)
As described above, the pattern retardation layer having a function of converting from linearly polarized light to circularly polarized light or from circularly polarized light to linearly polarized light preferably has a retardation of ¼ of the wavelength. In general, it is called a quarter-wave plate, and Re = 137.5 nm is an ideal value at a visible light wavelength of 550 nm.
Further, the pattern retardation layer for converting linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light is not limited to having a retardation of ¼ wavelength. For example, a retardation of -1/4 or 3/4 of the wavelength may be used, and the retardation may be ¼ ± n / 2 (n is an integer) of the wavelength when expressed by a general formula.
Patterning in which the slow axis of the first region and the slow axis of the second region are orthogonal to each other may be performed by alternately forming regions having a retardation of -1/4 or 1/4 of the wavelength. At this time, the slow axes of each region are almost orthogonal. Further, the retardation of 1/4 and 3/4 of the wavelength may be patterned, and the slow axes of the mutual regions at this time are substantially parallel. However, the rotation directions of the circularly polarized light in the respective regions are reversed.
Further, in the patterning of the quarter of the wavelength and the retardation of the quarter, the retardation of 1/2 or −1/2 of the wavelength may be formed after the quarter of the wavelength is formed on the entire surface.
When the cellulose acylate film arranged on the surface A side of the polarizer has a retardation of ¼ of the wavelength, the Re (550) value of the first region contained in the optical film, and the optical film The Re (550) value of the second region contained therein is preferably 30 to 250 nm, more preferably 50 to 230 nm, particularly preferably 100 to 200 nm, and 105 to 180 nm. Is more particularly preferable, 115 to 160 nm is further preferable, and 130 to 150 nm is more preferable.

  Also, from the viewpoint of changing the polarization state of the light that has passed through the first region and the second region when displaying 3D images from linearly polarized light to circularly polarized light, or from circularly polarized light to linearly polarized light, The total Re (550) of the retardation layer and the support is preferably 110 to 165 nm, more preferably 110 to 155 nm, and still more preferably 120 to 145 nm. In particular, the entire Re (550) of the pattern retardation layer and the support is in the above range, and the slow axes of the first region and the second region are substantially orthogonal to each other, so that the right-eye image and the left-eye can be accurately obtained. It is preferable from the viewpoint that the polarization state of the image for use can be changed.

<Second cellulose acylate film>
In the polarizing plate of the present invention, it is preferable that a second cellulose acylate film is further disposed on the surface B side opposite to the surface A of the polarizer.
There is no restriction | limiting in particular as said 2nd cellulose acylate film, A well-known cellulose acylate film can be used. Of course, the Knoop hardness of the second cellulose acylate film is not particularly limited.

(Composition of the second cellulose acylate film)
The cellulose acylate contained in the second cellulose acylate film is not particularly limited, but the acyl group substitution degree is preferably 2.0 to 3.0,
It is more preferably 2.2 to 2.95, and particularly preferably 2.30 to 2.92.

  The acyl group of the cellulose acylate contained in the second cellulose acylate film is not particularly limited, and is the same as the acyl group of the cellulose acylate contained in the cellulose acylate film disposed on the surface A side of the polarizer. Can be used.

It is preferable to add a plasticizer to the second cellulose acylate film. As the plasticizer that can be added to the second cellulose acylate film, an aliphatic ester oligomer comprising a repeating unit derived from an aliphatic dicarboxylic acid and a repeating unit derived from an aliphatic diol is preferable from the viewpoint of Rth expression. .
The aliphatic ester oligomer that can be used in the second cellulose acylate film preferably contains 10 to 40% by mass of a plasticizer, more preferably 10 to 30% by mass, based on the cellulose acylate. It is still more preferable to contain 10-25 mass%.

  In addition to the second cellulose acylate film, additives that can be used for the cellulose acylate film disposed on the surface A side of the polarizer and other known additives may be added. .

(Method for producing second cellulose acylate film)
Although there is no restriction | limiting in particular as a manufacturing method of a said 2nd cellulose acylate film, For example, the method similar to the manufacturing method of the said cellulose acylate film arrange | positioned at the surface A side of the said polarizer can be mentioned. .

(Characteristics of the second cellulose acylate film)
The thickness of the second cellulose acylate film is preferably 40 μm or less, more preferably 10 to 35 μm, and particularly preferably 15 to 25 μm.

  In the polarizing plate of the present invention, it is preferable that Rth of the second cellulose acylate film disposed on the surface B side of the polarizer is −10 to 10 nm (Rth is retardation in the film thickness direction). Represents). The Rth of the second cellulose acylate film is more preferably -8 to 8 nm, and particularly preferably -6 to 6 nm.

<Layers other than cellulose acylate film>
The polarizing plate of the present invention may have a layer other than the second cellulose acylate film on the surface B side of the polarizer as long as it does not contradict the gist of the present invention.
The layer other than the second cellulose acylate film disposed on the surface B side of the polarizer is a layer other than the cycloolefin polymer layer, and the ethylenically unsaturated monomer is polymerized. As a layer other than the layer to be formed, an acrylic polymer layer is preferable.

(Acrylic polymer layer)
Examples of the acrylic polymer layer include a layer formed from a composition containing a (meth) acrylic acid resin as a main component.
The repeating structural unit of the (meth) acrylic acid resin is not particularly limited. The (meth) acrylic resin preferably has a repeating structural unit derived from a (meth) acrylic acid ester monomer as a repeating structural unit.

  The (meth) acrylic resin is a concept including both a methacrylic resin and an acrylic resin. The (meth) acrylic resin also includes acrylate / methacrylate derivatives, particularly acrylate / methacrylate (co) polymers.

  The (meth) acrylic acid resin further polymerizes at least one selected from a hydroxyl group-containing monomer, an unsaturated carboxylic acid and a monomer represented by the following general formula (201) as a repeating structural unit. It may contain a repeating structural unit constructed by

Formula (201)
CH ₂ = C (X) R ²⁰¹

(In the formula, R ²⁰¹ represents a hydrogen atom or a methyl group, and X represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, a —CN group, a —CO—R ²⁰² group, or —O—CO—R. ²⁰³ represents a group, and R ²⁰² and R ²⁰³ represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)

The (meth) acrylic acid ester is not particularly limited, and examples thereof include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, cyclohexyl acrylate, and benzyl acrylate. Acrylic acid esters; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, methacrylic acid esters such as benzyl methacrylate; These may be used alone or in combination of two or more. Among these, methyl methacrylate is particularly preferable from the viewpoint of excellent heat resistance and transparency.
When the (meth) acrylic acid ester is used, the content ratio in the monomer component to be subjected to the polymerization step is preferably 10 to 100% by weight, more preferably 10%, in order to sufficiently exhibit the effects of the present invention. -100% by weight, more preferably 40-100% by weight, particularly preferably 50-100% by weight.

The hydroxyl group-containing monomer is not particularly limited. For example, 2- (hydroxyalkyl) acrylic acid ester such as α-hydroxymethylstyrene, α-hydroxyethylstyrene, methyl 2- (hydroxyethyl) acrylate; 2 2- (hydroxyalkyl) acrylic acid such as-(hydroxyethyl) acrylic acid; and the like. These may be used alone or in combination of two or more.
In the case of using the hydroxyl group-containing monomer, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by weight, more preferably 0 to 0% in order to sufficiently exert the effects of the present invention. It is 20% by weight, more preferably 0 to 15% by weight, particularly preferably 0 to 10% by weight.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, α-substituted methacrylic acid and the like. These may be used alone or in combination of two or more. You may use together. Among these, acrylic acid and methacrylic acid are preferable in that the effects of the present invention are sufficiently exhibited.
When the unsaturated carboxylic acid is used, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by weight, more preferably 0 to 20%, in order to sufficiently exhibit the effects of the present invention. % By weight, more preferably 0-15% by weight, particularly preferably 0-10% by weight.

Examples of the monomer represented by the general formula (201) include styrene, vinyl toluene, α-methyl styrene, acrylonitrile, methyl vinyl ketone, ethylene, propylene, vinyl acetate, and the like. You may use, and may use 2 or more types together. Among these, styrene and α-methylstyrene are particularly preferable in that the effects of the present invention are sufficiently exhibited.
When the monomer represented by the general formula (201) is used, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% in order to sufficiently exhibit the effects of the present invention. %, More preferably 0 to 20% by weight, still more preferably 0 to 15% by weight, particularly preferably 0 to 10% by weight.

The monomer component may form a lactone ring after polymerization. In that case, it is preferable to polymerize the monomer component to obtain a polymer having a hydroxyl group and an ester group in the molecular chain.
As a polymerization reaction form for polymerizing the monomer component to obtain a polymer having a hydroxyl group and an ester group in the molecular chain, a polymerization form using a solvent is preferable, and solution polymerization is particularly preferable. .
For example, a lactone ring structure described in JP 2007-316366 A, JP 2005-189623 A, WO 2007/032304, WO 2006/025445 is also preferable. It is.

-Lactone ring-containing polymer-
The lactone ring-containing polymer is not particularly limited as long as it has a lactone ring, but preferably has a lactone ring structure represented by the following general formula (401).

General formula (401):

In the general formula (401), R ⁴⁰¹ , R ⁴⁰² and R ⁴⁰³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the organic residue may contain an oxygen atom. . Here, the organic residue having 1 to 20 carbon atoms is preferably a methyl group, an ethyl group, an isopropyl group, an n-butyl group, a t-butyl group, or the like.

  The content ratio of the lactone ring structure represented by the general formula (401) in the structure of the lactone ring-containing polymer is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, and still more preferably 10 to 60% by mass. %, Particularly preferably 10 to 50% by mass. By setting the content ratio of the lactone ring structure to 5% by mass or more, the heat resistance and surface hardness of the obtained polymer tend to be improved, and by setting the content ratio of the lactone ring structure to 90% by mass or less. The moldability of the obtained polymer tends to be improved.

  The method for producing the lactone ring-containing polymer is not particularly limited, but preferably, after obtaining a polymer (p) having a hydroxyl group and an ester group in the molecular chain by a polymerization step, the obtained polymer ( It is obtained by carrying out a lactone cyclization condensation step for introducing a lactone ring structure into the polymer by heat-treating p).

  The weight average molecular weight of the lactone ring-containing polymer is preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000, still more preferably 10,000 to 500,000, particularly preferably. 50,000 to 500,000.

  The lactone ring-containing polymer has a mass reduction rate within a range of 150 to 300 ° C. in dynamic TG measurement, preferably 1% or less, more preferably 0.5% or less, and still more preferably 0.3% or less. It is good. As a method for measuring dynamic TG, the method described in JP-A-2002-138106 can be used.

  Since the lactone ring-containing polymer has a high cyclization condensation reaction rate, there is little dealcoholization reaction in the production process of the molded product, and bubbles and silver stripes (silver streaks) are formed in the molded product after molding due to the alcohol. The disadvantage of entering can be avoided. Furthermore, since the lactone ring structure is sufficiently introduced into the polymer due to a high cyclization condensation reaction rate, the obtained lactone ring-containing polymer has high heat resistance.

  The lactone ring-containing polymer has a coloring degree (YI) of preferably 6 or less, more preferably 3 or less, still more preferably 2 or less, and particularly preferably 1 or less when a chloroform solution having a concentration of 15% by mass is used. . If the degree of coloring (YI) is 6 or less, problems such as loss of transparency due to coloring are unlikely to occur, and therefore, it can be preferably used in the present invention.

  The lactone ring-containing polymer has a 5% mass reduction temperature in thermal mass spectrometry (TG) of preferably 330 ° C. or higher, more preferably 350 ° C. or higher, and still more preferably 360 ° C. or higher. The 5% mass reduction temperature in thermal mass spectrometry (TG) is an indicator of thermal stability, and by setting it to 330 ° C. or higher, sufficient thermal stability tends to be exhibited. The thermal mass spectrometry can use the apparatus for measuring the dynamic TG.

  The lactone ring-containing polymer has a glass transition temperature (Tg) of preferably 115 ° C. or higher, more preferably 125 ° C. or higher, further preferably 130 ° C. or higher, particularly preferably 135 ° C. or higher, and most preferably 140 ° C. or higher. .

  The total amount of residual volatile components contained in the lactone ring-containing polymer is preferably 5,000 ppm or less, more preferably 2,000 ppm or less, still more preferably 1,500 ppm, and particularly preferably 1,000 ppm. If the total amount of residual volatile components is 5,000 ppm or less, it is preferable because coloring defects due to alteration during molding, foaming, and molding defects such as silver streak are unlikely to occur.

  The lactone ring-containing polymer has a total light transmittance of 85% or more, more preferably 88% or more, and still more preferably measured by a method based on ASTM-D-1003 for a molded product obtained by injection molding. 90% or more. The total light transmittance is an index of transparency, and when it is 85% or more, the transparency tends to be improved.

In the case of a polymerization form using a solvent, the polymerization solvent is not particularly limited. For example, aromatic hydrocarbon solvents such as toluene, xylene, and ethylbenzene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ether solvents such as tetrahydrofuran Etc., and only one of these may be used, or two or more may be used in combination.
In addition, when the (meth) acrylic resin is dissolved in an organic solvent and formed by solution casting, the organic solvent at the time of synthesizing the (meth) acrylic resin is not limited than when melt film formation is performed. Alternatively, the synthesis may be performed using an organic solvent having a high boiling point.

During the polymerization reaction, a polymerization initiator may be added as necessary. Although it does not specifically limit as a polymerization initiator, For example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-amyl Organic peroxides such as peroxy-2-ethylhexanoate; 2,2′-azobis (isobutyronitrile), 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis (2, Azo compounds such as 4-dimethylvaleronitrile), and the like. These may be used alone or in combination of two or more. The amount of the polymerization initiator used is not particularly limited as long as it is appropriately set according to the combination of the monomers used and the reaction conditions.
The weight average molecular weight of the polymer can be adjusted by adjusting the amount of the polymerization initiator.

  When performing the polymerization, it is preferable to control the concentration of the produced polymer in the polymerization reaction mixture to be 50% by weight or less in order to suppress gelation of the reaction solution. Specifically, when the concentration of the produced polymer in the polymerization reaction mixture exceeds 50% by weight, it is preferable that the polymerization solvent is appropriately added to the polymerization reaction mixture and controlled to be 50% by weight or less. . The concentration of the produced polymer in the polymerization reaction mixture is more preferably 45% by weight or less, still more preferably 40% by weight or less.

  The form in which the polymerization solvent is appropriately added to the polymerization reaction mixture is not particularly limited, and the polymerization solvent may be added continuously or intermittently. By controlling the concentration of the produced polymer in the polymerization reaction mixture in this way, the gelation of the reaction solution can be more sufficiently suppressed. The polymerization solvent to be added may be the same type of solvent used during the initial charging of the polymerization reaction or may be a different type of solvent, but is the same as the solvent used during the initial charging of the polymerization reaction. It is preferable to use different types of solvents. Further, the polymerization solvent to be added may be only one type of solvent or a mixed solvent of two or more types.

As the acrylic polymer layer, a conventionally known optical film can be used.
As an optical film used as the acrylic polymer layer, an optical film made of a (meth) acrylic resin containing a styrene resin described in Japanese Patent No. 4570042 and a glutarimide ring structure described in Japanese Patent No. 5041532 are mainly used. An optical film made of a (meth) acrylic resin in the chain, an optical film made of a (meth) acrylic resin having a lactone ring structure described in JP2009-122664A, and a glutar described in JP2009-139754A An optical film made of a (meth) acrylic resin having an acid anhydride unit can be used.

<Hard coat layer>
There is no restriction | limiting in particular as long as it is not contrary to the meaning of this invention as said hard-coat layer, A well-known hard-coat layer etc. can be used.

The hard coat layer preferably has a thickness of 0.1 to 6 μm, more preferably 3 to 6 μm. By having a thin hard coat layer in the above range, an optical film including a hard coat layer that has improved physical properties such as brittleness and curl suppression, reduced weight, and reduced manufacturing costs is obtained. Further, when the substrate film is a cellulose acylate having a large elastic modulus, the pencil hardness can be remarkably increased by setting it to be in the range of the specific elastic modulus.
The hard coat layer used in the present invention is a layer for imparting hardness and scratch resistance to the film. The said hard-coat layer can be formed by apply | coating a coating composition on a base film (cellulose acylate film), and making it harden | cure, for example. Moreover, you may laminate | stack another functional layer on a hard-coat layer for the purpose of adding another function. Also, by adding fillers and additives to the hard coat layer, chemical performance such as mechanical, electrical and optical physical performance and water / oil repellency can be imparted to the hard coat layer itself. .

  The hard coat layer is preferably formed by curing the curable composition. The curable composition is preferably prepared as a liquid coating composition. An example of the said coating composition contains the monomer or oligomer for matrix formation binders, polymers, and an organic solvent. A hard coat layer can be formed by curing the coating composition after coating. For curing, a crosslinking reaction or a polymerization reaction can be used.

(Monomer or oligomer for matrix forming binder)
Examples of matrix forming binder monomers or oligomers that can be used include ionizing radiation curable polyfunctional monomers and polyfunctional oligomers. The polyfunctional monomer or polyfunctional oligomer is preferably a monomer capable of crosslinking reaction or polymerization reaction. The functional group of the ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer is preferably a light, electron beam, or radiation polymerizable group, and among them, a photopolymerizable functional group is preferable.

  Examples of the photopolymerizable functional group include unsaturated polymerizable functional groups such as (meth) acryloyl group, vinyl group, styryl group, and allyl group, and ring-opening polymerizable functional groups such as epoxy compounds. Of these, a (meth) acryloyl group is preferred.

As a specific example of a photopolymerizable polyfunctional monomer having a photopolymerizable functional group,
(Meth) acrylic acid diesters of alkylene glycol such as neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate;
(Meth) acrylic acid diesters of polyoxyalkylene glycols such as triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate;
(Meth) acrylic acid diesters of polyhydric alcohols such as pentaerythritol di (meth) acrylate;
(Meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts such as 2,2-bis {4- (acryloxy-diethoxy) phenyl} propane and 2,2-bis {4- (acryloxy-polypropoxy) phenyl} propane ;
Etc.

  Furthermore, urethane (meth) acrylates, polyester (meth) acrylates, isocyanuric acid acrylates, and epoxy (meth) acrylates are also preferably used as the photopolymerizable polyfunctional monomer.

Among the above, esters of polyhydric alcohol and (meth) acrylic acid are preferable, and polyfunctional monomers having three or more (meth) acryloyl groups in one molecule are more preferable.
Specifically, (di) pentaerythritol tri (meth) acrylate, (di) pentaerythritol tetra (meth) acrylate, (di) pentaerythritol penta (meth) acrylate, (di) pentaerythritol hexa (meth) acrylate, tri Pentaerythritol triacrylate, tripentaerythritol hexatriacrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO-modified phosphate tri (meth) acrylate, 1,2,4-cyclohexanetetra (meth) acrylate Pentaglycerol triacrylate, 1,2,3-cyclohexane tetramethacrylate, polyester polyacrylate and caprolactone-modified tris (acryloyloxyethyl) isocyanurate, and the like.
In the present specification, “(meth) acrylate”, “(meth) acrylic acid”, and “(meth) acryloyl” represent “acrylate or methacrylate”, “acrylic acid or methacrylic acid”, and “acryloyl or methacryloyl”, respectively. .

Furthermore, resins having three or more (meth) acryloyl groups, such as relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins And oligomers or prepolymers such as polyfunctional compounds such as polyhydric alcohols.
As specific compounds of polyfunctional acrylate compounds having three or more (meth) acryloyl groups, JP-A-2007-256844 [0096] and the like can be referred to.

As urethane acrylates, for example, alcohols, polyols, and / or hydroxyl group-containing compounds such as hydroxyl group-containing acrylates are reacted with isocyanates, and if necessary, polyurethane compounds obtained by these reactions (meth) Mention may be made of urethane acrylate compounds obtained by esterification with acrylic acid.
As specific examples of specific compounds, reference can be made to the description of [0017] in JP-A-2007-256844.

  Use of isocyanuric acid acrylates is preferable because curling can be further reduced. Examples thereof include isocyanuric acid diacrylates and isocyanuric acid triacrylates, and examples of specific compounds can be referred to JP-A-2007-256844 [0018] to [0021].

  In the hard coat layer, an epoxy compound can be further used to reduce shrinkage due to curing. As monomers having an epoxy group for constituting this, monomers having two or more epoxy groups in one molecule are used, and examples thereof include JP-A Nos. 2004-264563, 2004-264564, and Examples thereof include epoxy monomers described in 2005-37737, 2005-37738, 2005-140862, 2005-140862, 2005-140863, 2002-322430 and the like. It is also preferable to use a compound having both epoxy and acrylic functional groups such as glycidyl (meth) acrylate.

(Polymer compound)
The hard coat layer may contain a polymer compound. The explanation and preferred specific examples of the polymer compound are the same as those described in JP 2012-215812 A, and the contents described in this gazette are incorporated in the present specification.

(Curable composition)
Examples and preferred specific examples of the curable composition that can be used for forming the hard coat layer are the same as those described in JP 2012-215812 A, and the contents described in this gazette are described in this specification. Incorporated into.

(Properties of hard coat layer)
The hard coat layer is preferably excellent in scratch resistance. Specifically, it is preferable to achieve 3H or higher when a pencil hardness test that is an index of scratch resistance is performed.

  The polarizing plate of the present invention is useful for various applications other than the polarizing plate disposed on the image display surface. In order to show the function suitable for each use, you may have another layer with the said cellulose acylate film and the said hard-coat layer. For example, in addition to the antiglare layer and the clear hard coat layer, an antireflection layer, an antistatic layer, an antifouling layer, and the like may be included.

In particular, since image display screens having various types of touch panels that have become popular in recent years are required to have fingerprint resistance and antifouling properties, a fingerprint resistant layer or antifouling layer is formed on the cellulose acylate film. It is also useful to form.
Regarding the anti-fingerprint layer and the antifouling layer, for example, Japanese Patent No. 4517590, Japanese Patent No. 4638954, International Publication WO2010 / 090116, and International Publication WO2011 / 105594 can be referred to.

  Moreover, the said cellulose acylate film can also be used as a base material of the transparent conductive film with a hard-coat layer for a touchscreen use.

  The image display device is not limited, and may be a liquid crystal display device including a liquid crystal cell, an organic EL image display device including an organic EL layer, or a plasma image display device. The cellulose acylate film has good bonding properties with a polarizer and is suitable for use in a liquid crystal display device having a polarizing plate as an essential member.

In addition to the antiglare layer or the clear hard coat layer, the polarizing plate protective film used on the surface side of the display device preferably has an antireflection layer, an antistatic layer, and an antifouling layer.
Further, when the polarizing plate is produced, when the cellulose acylate film has an in-plane slow axis, it is preferably bonded so that the in-plane slow axis and the transmission axis of the polarizer are parallel or orthogonal to each other. .

<Production method of polarizing plate>
The polarizing plate of the present invention can be produced by a general method.

  As said polarizer, what was manufactured by the conventionally well-known method can be used. For example, a film made of a hydrophilic polymer such as polyvinyl alcohol or ethylene-modified polyvinyl alcohol having an ethylene unit content of 1 to 4 mol%, a polymerization degree of 2000 to 4000, and a saponification degree of 99.0 to 99.99 mol%, A film stretched by treatment with a dichroic dye such as the above, or a film oriented by treating a plastic film such as vinyl chloride is used.

  Moreover, as a method of obtaining a polarizer film of 10 μm or less by stretching and dyeing in the state of a laminated film in which a polyvinyl alcohol layer is formed on a substrate, Patent No. 5048120, Patent No. 5143918, Patent No. 5048120 No. 4, Patent No. 4691205, Patent No. 4751481 and Patent No. 4751486 can be cited, and known techniques relating to these polarizers can also be preferably used for the polarizing plate of the present invention.

  The polarizer thus obtained is bonded to a polarizing plate protective film.

  It is preferable that the manufacturing method of the polarizing plate in this invention includes the process of laminating | stacking two polarizing plate protective films on both surfaces of the polarizer obtained by the said method.

  For the lamination, an adhesive is usually used. The adhesive layer between the polarizer and the polarizing plate protective film on both sides can have a thickness of about 0.01 to 30 μm, preferably 0.01 to 10 μm, more preferably 0.05 to 5 μm. is there. If the thickness of the adhesive layer is within this range, no adhesion or practical problem will be obtained without floating or peeling between the laminated polarizing plate protective film and the polarizer.

As one of the preferable adhesives, an aqueous adhesive, that is, an adhesive component dissolved or dispersed in water can be exemplified, and an adhesive made of an aqueous polyvinyl alcohol resin solution is preferably used.
In an adhesive comprising an aqueous polyvinyl alcohol resin solution, the polyvinyl alcohol resin includes a vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as vinyl acetate and this. Examples include vinyl alcohol copolymers obtained by saponifying a copolymer with other polymerizable monomers, and modified polyvinyl alcohol polymers obtained by partially modifying their hydroxyl groups.
To this adhesive, a polyvalent aldehyde, a water-soluble epoxy compound, a melamine compound, a zirconia compound, a zinc compound, a glyoxylate and the like may be added as a crosslinking agent. When an aqueous adhesive is used, the thickness of the adhesive layer obtained therefrom is usually 1 μm or less.

Another preferred adhesive is a curable adhesive composition containing an epoxy compound that is cured by irradiation with active energy rays or heating. Here, the curable epoxy compound has at least two epoxy groups in the molecule. In this case, the adhesive between the polarizer and the protective film is applied to the coating layer of the adhesive composition by irradiating active energy rays or applying heat, and a curable epoxy compound contained in the adhesive. It can carry out by the method of hardening. Curing of the epoxy compound is generally performed by cationic polymerization of the epoxy compound. Further, from the viewpoint of productivity, this curing is preferably performed by irradiation with active energy rays.
When a curable adhesive is used, the thickness of the adhesive layer obtained therefrom is usually about 0.5 to 5 μm.

  When using a curable adhesive, after bonding a film using a bonding roll, drying is performed as necessary, and the curable adhesive is cured by irradiating with active energy rays or heating. . The light source of the active energy ray is not particularly limited, but an active energy ray having a light emission distribution at a wavelength of 400 nm or less is preferable. A microwave excited mercury lamp, a metal halide lamp, or the like is preferably used.

  From the viewpoint of weather resistance, refractive index, cationic polymerizability, etc., the epoxy compound contained in the curable adhesive composition is preferably one that does not contain an aromatic ring in the molecule. Examples of epoxy compounds that do not contain an aromatic ring in the molecule include hydrogenated epoxy compounds, alicyclic epoxy compounds, and aliphatic epoxy compounds. Epoxy compounds suitably used for such a curable adhesive composition are described in detail in, for example, Japanese Patent Application Laid-Open No. 2004-245925.

[Liquid Crystal Display]
The liquid crystal display device of the present invention includes a liquid crystal cell and at least one polarizing plate of the present invention.
An example of the arrangement method of the cellulose acylate film is a surface protective film for a polarizing plate arranged inside the polarizer (that is, between the polarizer and the liquid crystal cell) without having a hard coat layer. Another example of the arrangement method of the cellulose acylate film is a surface arranged inside the polarizer (that is, between the polarizer and the liquid crystal cell) in the polarizing plate on the display surface side with the hard coat layer. It is a protective film. The polarizing plate of the present invention is preferably a polarizing plate disposed on the display surface side, and is preferably disposed with the cellulose acylate film on the display surface side outer side. In the liquid crystal display device of the present invention, the cycloolefin polymer layer disposed on the surface A side of the polarizer is more from the liquid crystal cell than the cellulose acylate film disposed on the surface A side of the polarizer. It is preferable that the polarizing plate is disposed so as to be close.
As for other configurations, any configuration of a known liquid crystal display device can be adopted. There are no particular restrictions on the mode, and TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Ferroelectric Liquid Crystal), OCB (Optic STP). It can be configured as a liquid crystal display device in various display modes such as Nematic), VA (Vertically Aligned) and HAN (Hybrid Aligned Nematic).

As the liquid crystal display device of the present invention, a transmissive liquid crystal display device is preferable, and the transmissive liquid crystal display device is usually composed of a backlight, a liquid crystal cell, and two polarizing plates whose transmission axes are orthogonal, The two polarizing plates are bonded to the viewing side and the backlight side of the liquid crystal cell via an adhesive layer.
The liquid crystal cell includes a liquid crystal layer and two glass substrates provided on both sides of the liquid crystal layer.
As the glass substrate for the liquid crystal display device, silicate glass is used, preferably silica glass or borosilicate glass is used, and most preferably non-alkali borosilicate glass is used. If an alkali component is contained in a glass substrate for a liquid crystal display device, the alkali component is eluted and the TFT may be damaged. Here, the alkali-free borosilicate glass is a glass that does not substantially contain an alkali component, and specifically, a glass having an alkali component of 1000 ppm or less. The content of the alkali component in the present invention is preferably 500 ppm or less, more preferably 300 ppm or less of the alkali component.

  The glass substrate for a liquid crystal display device is a plate-like body having a substantially rectangular shape in plan view, and preferably has a plate thickness of 0.01 mm to 1.1 mm. This is because if the thickness is less than 0.01 mm, it is easily affected by light interference or internal distortion due to deformation of the glass substrate for display to be evaluated, and if it is too thick, the luminance at the time of evaluation decreases. A more preferable plate thickness is 0.1 mm to 0.7 mm, and a further preferable plate thickness is 0.1 mm to 0.5 mm.

  The features of the present invention will be described more specifically with reference to examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[Production Example 1: Production of outer protective film]
(Preparation of core layer cellulose acylate dope)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution.
Composition of core layer cellulose acylate dope:
----------------------------------
Cellulose acetate with an acetyl substitution degree of 2.88 100 parts by mass ester oligomer (the following plasticizer 1) 10 parts by mass Polarizer durability improver (the following compound 2-10) 4 parts by mass UV absorber (the following UV agent A) 4 parts by mass Part methylene chloride (first solvent) 438 parts by mass methanol (second solvent) 65 parts by mass ---------------------------- ------

(Preparation of outer layer cellulose acylate dope)
10 parts by mass of the following matting agent solution was added to 90 parts by mass of the core layer cellulose acylate dope to prepare an outer layer cellulose acetate solution.
Composition of matting agent solution:
----------------------------------
Silica particles having an average particle size of 20 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 2 parts by mass Methylene chloride (first solvent) 76 parts by mass Methanol (second solvent) 11 parts by mass Core layer cellulose acylate dope 1 part by mass ---------------------------------

(Preparation of cellulose acylate film)
Three layers of the core layer cellulose acylate dope and the outer layer cellulose acylate dope on both sides of the core layer cellulose acylate dope were simultaneously cast on a drum at 20 ° C. from the casting port. The film was peeled off at a solvent content of about 20% by mass, both ends in the width direction of the film were fixed with tenter clips, and the film was dried while being stretched 1.1 times in the lateral direction with a residual solvent of 3 to 15% by mass. . Thereafter, a cellulose acylate film having a thickness of 25 μm was produced by conveying between rolls of a heat treatment apparatus, and designated as cellulose acylate 001.

  A cellulose acylate film (cellulose acylate 002 to 005) shown in Table 1 below was produced under the same conditions as those for producing the cellulose acylate film 001 except that the dope formulation and the film thickness when applied were changed.

Cycloolefin polymer layer (production of cycloolefin 101)
The composition prepared by mixing the cellulose acylate 001 prepared above as shown in the following table was applied using a gravure coater, dried at 25 ° C. for 1 minute, and then dried at 80 ° C. for about 5 minutes to obtain a film thickness of 10 μm. The cycloolefin polymer layer (cycloolefin 101) was obtained. In this way, a laminate of cellulose acylate 001 and cycloolefin 101 was obtained.

Composition of coating solution for cycloolefin polymer layer:
----------------------------------
ZEONOR 1020R: Cyclic polyolefin resin (manufactured by Nippon Zeon Co., Ltd.)
100 parts by mass cyclohexane 510 parts by mass cyclohexanone 57 parts by mass ---------------------------------

Cycloolefin polymer layer (production of cycloolefin 102)
A cycloolefin polymer layer 102 having a film thickness of 5 μm was obtained under the same conditions as in the preparation of the cycloolefin 101 except that the film thickness when applying the composition was changed. In this way, a laminate of cellulose acylate 001 and cycloolefin 102 was obtained.

  Under the same conditions as the production of cycloolefin 101 except that the cellulose acylate 001 used was changed to cellulose acylate 002-005, the cycloolefin polymer layer 101 was applied to cellulose acylate 002-005, and cellulose acylate 002 was obtained. A laminate of any of ˜005 and cycloolefin 101 was prepared.

(Preparation of hard coat layer)
The following hard coat curable composition hard coat 1 was prepared as a coating solution for forming a hard coat layer.

Each of the cellulose acylate films of the laminate of the cellulose acylate 001 to 005 produced in each of the above and the cycloolefin 101 and the laminate of the cellulose acylate 001 and the cycloolefin 102 are prepared as the hard coat 1. The hard coat layer having a thickness of 5 μm is coated on the surface on the side, dried at 100 ° C. for 60 seconds, irradiated with UV at 1.5 kW and 300 mJ under conditions of 0.1% nitrogen or less, and cured. Formed. The film thickness was adjusted by using a slot die and adjusting the coating amount in a die coating method.
Thus, a hard coat layer, an outer protective film that is a laminate of any of cellulose acylates 001 to 005 and cycloolefin 101, and a laminate of the hard coat layer, cellulose acylate 001 and cycloolefin 102 An outer protective film was prepared.

[Production Example 2: Production of cell-side protective film]
(Preparation of core layer cellulose acylate dope)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution.
Composition of core layer cellulose acylate dope:
----------------------------------
Cellulose acetate having an acetyl substitution degree of 2.88 100 parts by mass Plasticizer 2 (the following structure) 15 parts by mass Methylene chloride (first solvent) 426 parts by mass Methanol (second solvent) 64 parts by mass -------- -------------------------

(Preparation of outer layer cellulose acylate dope)
10 parts by mass of the following matting agent solution was added to 90 parts by mass of the core layer cellulose acylate dope to prepare an outer layer cellulose acetate solution.
Composition of matting agent solution:
----------------------------------
Silica particles having an average particle size of 20 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 2 parts by mass Methylene chloride (first solvent) 76 parts by mass Methanol (second solvent) 11 parts by mass Core layer cellulose acylate dope 1 part by mass ---------------------------------

(Preparation of cellulose acylate film)
Three layers of the core layer cellulose acylate dope and the outer layer cellulose acylate dope on both sides of the core layer cellulose acylate dope were simultaneously cast on a drum at 20 ° C. from the casting port. The film was peeled off in a state where the solvent content was approximately 20% by mass, both ends in the width direction of the film were fixed with tenter clips, and the film was dried while being stretched 1.1 times in the lateral direction in a state where the residual solvent was 3 to 15%. Thereafter, a cellulose acylate film having a thickness of 20 μm was produced by conveying between rolls of a heat treatment apparatus, and a cellulose acylate 301 was obtained. In addition, all the outer layers of the cellulose acylates 301 to 305 were each 2 μm, and the thickness of the core layer was adjusted to adjust the overall thickness.

  A cellulose acylate film having a thickness of 25 μm (cellulose acylate 303) and a cellulose acylate film having a thickness of 40 μm (cellulose acylate 304) were produced in the same manner as described above except that the film thickness was changed.

  Cellulose acetate 305 was produced in the same manner as cellulose acetate 301 except that the core layer dope was changed and the following cellulose acetate solution was used.

Composition of core layer cellulose acylate dope:
----------------------------------
Cellulose acetate with an acetyl substitution degree of 2.88 100 parts by weight Triphenyl phosphate 12 parts by weight Methylene chloride (first solvent) 426 parts by weight Methanol (second solvent) 64 parts by weight ----------- -----------------------

Cycloolefin polymer layer (production of cycloolefin 201)
The composition prepared as described in the following table was applied to the cellulose acylate 301 prepared above using a gravure coater, dried at 25 ° C. for 1 minute, and then dried at 80 ° C. for about 5 minutes to obtain a film thickness of 10 μm. The cycloolefin polymer layer (cycloolefin 201) was obtained. In this way, a laminate of cellulose acylate 301 and cycloolefin 201 was obtained.

Composition of coating solution for cycloolefin polymer layer:
----------------------------------
ZEONOR 1020R: Cyclic polyolefin resin (manufactured by Nippon Zeon Co., Ltd.)
100 parts by mass cyclohexane 510 parts by mass cyclohexanone 57 parts by mass ---------------------------------

Cycloolefin polymer layer (production of cycloolefin 202)
A cycloolefin polymer layer (cycloolefin 202) having a thickness of 20 μm was obtained by extrusion molding using pellets of norbornene-based resin (“ZEONOR1060” manufactured by Nippon Zeon Co., Ltd.) dried at 100 ° C. for 5 hours.

上記一般式中、Ｒ¹は水素原子、Ｒ²およびＲ³はメチル基であるラクトン環構造を有する（メタ）アクリル系樹脂｛共重合モノマー質量比＝メタクリル酸メチル／２−（ヒドロキシメチル）アクリル酸メチル＝８／２、ラクトン環化率約１００％、ラクトン環構造の含有割合１９．４％、重量平均分子量１３３０００、メルトフローレート６．５ｇ／１０分（２４０℃、１０ｋｇｆ）、Ｔｇ１３１℃｝９０質量部と、アクリロニトリル−スチレン（ＡＳ）樹脂｛トーヨーＡＳ ＡＳ２０、東洋スチレン社製｝１０質量部との混合物（Ｔｇ１２７℃）のペレットを二軸押し出し機に供給し、約２８０℃でシート状に溶融押し出しして、厚さ４０μｍのラクトン環構造を有する（メタ）アクリル系樹脂シートを得た。この未延伸シートを、１６０℃の温度条件下、縦２．０倍、横２．４倍に延伸して厚さ：２０μｍのアクリルポリマー層（アクリル２０３）を得た。 Acrylic polymer layer (production of acrylic 203)

(Meth) acrylic resin having a lactone ring structure in which R ¹ is a hydrogen atom, and R ² and R ³ are methyl groups in the above general formula {copolymerization monomer mass ratio = methyl methacrylate / 2- (hydroxymethyl) acrylic Methyl acid = 8/2, lactone cyclization rate about 100%, lactone ring structure content 19.4%, weight average molecular weight 133000, melt flow rate 6.5 g / 10 min (240 ° C., 10 kgf), Tg 131 ° C.} Pellets of a mixture (Tg 127 ° C.) of 90 parts by mass and 10 parts by mass of acrylonitrile-styrene (AS) resin {Toyo AS AS20, manufactured by Toyo Styrene Co., Ltd.} are supplied to a biaxial extruder and are formed into a sheet at about 280 ° C. By melt extrusion, a (meth) acrylic resin sheet having a lactone ring structure with a thickness of 40 μm was obtained. This unstretched sheet was stretched 2.0 times vertically and 2.4 times horizontally under a temperature condition of 160 ° C. to obtain an acrylic polymer layer (acrylic 203) having a thickness of 20 μm.

  Thus obtained cellulose acetate 301 to 305, a laminate of cellulose acylate 301 and cycloolefin 201, cycloolefin 202 and acrylic 203 are used as a cell-side protective film in each of Examples and Comparative Examples described later.

[Example 1]
(Preparation of polarizing plate)
1) Saponification of Cellulose Acylate 301 A cellulose acylate film (cellulose acylate 301) used as a cell-side protective film is placed in a 4.5 mol / L sodium hydroxide aqueous solution (saponification solution) adjusted to 37 ° C. for 1 minute. After dipping, the film was washed with water, then dipped in a 0.05 mol / L sulfuric acid aqueous solution for 30 seconds, and then passed through a washing bath. Then, draining with an air knife was repeated three times, and after dropping water, the film was retained in a drying zone at 70 ° C. for 15 seconds and dried to produce a saponified film.

2) Production of Polarizing Film According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, a circumferential speed difference was given between two pairs of nip rolls and stretched in the longitudinal direction to prepare a polarizing film having a thickness of 15 μm.

3) Bonding The polarizing film is sandwiched between cycloolefin 101 of the outer protective film obtained by corona-treating the cycloolefin 101 side of the laminate of cellulose acylate 301, cellulose acylate 001 and cycloolefin 101 by a known method. Then, using a PVA (manufactured by Kuraray Co., Ltd., PVA-117H) 3% aqueous solution as an adhesive, a polarizing plate was prepared by laminating with a roll-to-roll so that the polarizing axis and the longitudinal direction of the film were orthogonal.
The obtained polarizing plate was used as the polarizing plate of Example 1.

[Examples 2 to 4, 10 and Comparative Examples 2, 3, and 4]
Examples 2 to 4, 10 and Comparative Example 2, except that the cell-side protective film and the outer protective film were changed to the cell-side protective film and the outer protective film described in Table 4 below. Three or four polarizing plates were produced.

[Example 5]
The cycloolefin 101 side of the outer protective film obtained by corona treatment on the cycloolefin 101 side by a known method and the cycloolefin 201 side of the laminate of the cellulose acylate 301 and the cycloolefin 201 were corona treated by a known method. After sandwiching the polarizing film with the cycloolefin 201 of the cell-side protective film, the polarizing axis and the longitudinal direction of the film are orthogonal to each other using a PVA (manufactured by Kuraray Co., Ltd., PVA-117H) 3% aqueous solution as an adhesive. A polarizing plate of Example 5 was produced in the same manner as in Example 1 except that bonding was performed by roll-to-roll.

[Example 6]
A polarizing plate of Example 6 was produced in the same manner as in the production of the polarizing plate of Example 5 except that acrylic 203 (the surface was corona-treated by a known method) was used as the cell-side protective film.

[Example 7]
The outer protective film and the polarizing film were bonded together by using the same PVA (manufactured by Kuraray Co., Ltd., PVA-117H) 3% aqueous solution as an adhesive in the same manner as in the production of the polarizing plate of Example 1. The cell-side protective film uses an adhesive liquid (ethylenically unsaturated monomer polymerization layer solution) having the following composition as an adhesive liquid between the polarizer and cellulose acylate 301, and the ethylenically unsaturated monomer polymerization layer has a dry film thickness of 10 μm. After coating the solution for the ethylenically unsaturated monomer polymerization layer so as to be, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm with an oxygen concentration of about 0.1% under a nitrogen purge, A polarizing plate was produced by irradiating ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 60 mJ / cm ² , and bonding with a roll-to-roll so that the polarization axis and the longitudinal direction of the film were orthogonal.
The obtained polarizing plate was used as the polarizing plate of Example 7.

Adhesive liquid (ethylenically unsaturated monomer polymerization layer solution) composition:
----------------------------------
Tricyclodecane dimethanol dimethacrylate (100%)
[Manufactured by Shin-Nakamura Chemical Co., Ltd.] 53 parts by mass Irgacure 907 (100%)
[Ciba Specialty Chemicals Co., Ltd.] 2 parts by mass SP-13 (the following structure) 0.02 parts by mass MEK 45 parts by mass ------------------- ---------------

[Example 8]
According to Example 1 of Japanese Patent No. 4691205, a cyclohexane of a laminate of cellulose acylate 001 and cycloolefin 101 is formed on the surface of a 3 μm-thick PVA layer formed on an amorphous PET substrate via an adhesive layer. The polarizing plate of Example 8 was produced by bonding together the cycloolefin 101 of the outer protective film obtained by corona-treating the olefin 101 side by a known method.

[Comparative Example 1]
Cellulose acylate 001 and the outer protective film, which is a laminate of cellulose acylate 001 and cycloolefin 101, are bonded to PVA on the cellulose acylate 001 side (cellulose acylate 001 is surface-treated by saponification and bonded to PVA). A polarizing plate of Comparative Example 1 was produced in the same manner as in the production of the polarizing plate of Example 1, except that it was changed.

[Example 9]
A polarizing plate of Example 9 was produced in the same manner as in the production of the polarizing plate of Example 5 except that cycloolefin 202 (the surface was corona-treated by a known method) was used as the cell-side protective film.

[Examples 11 to 14]
A polarizing plate of Example 11 was produced in the same manner as in Example 5 except that the cell-side protective film was bonded in the same manner as in Example 7 using the ethylenically unsaturated monomer polymerization layer solution.
A polarizing plate of Example 12 was produced in the same manner as in Example 1 except that the outer protective film was bonded in the same manner as in Example 7 using the ethylenically unsaturated monomer polymerization layer solution.
A polarizing plate of Example 13 was produced in the same manner as in Example 1 except that the outer protective film and the cell-side protective film were bonded together using the solution for the ethylenically unsaturated monomer polymerization layer in the same manner as in Example 7. .
A polarizing plate of Example 14 was produced in the same manner as in Example 11 except that the outer protective film was bonded in the same manner as in Example 7 using the ethylenically unsaturated monomer polymerization layer solution.

[Evaluation]
(Knoop hardness)
Using a Fischer Instruments HM2000 hardness tester, a diamond indenter was pushed into the main surface of the cellulose acylate film or the hard coat surface under the conditions of a maximum indentation load of 20 mN, an indentation speed of 10 seconds, and a creep of 5 seconds. Knoop hardness was obtained from the relationship between the maximum indentation depth and the load. The obtained results are shown in Table 3 and Table 4 below.

(Polarizing plate durability evaluation)
About the polarizing plate produced above, 2 sets of samples (about 5 cm x 5 cm) which bonded the cell side surface to the glass plate with the adhesive (SK-2057: Soken Chemical Co., Ltd.) were produced. This was arranged in a crossed Nicol state, and the orthogonal transmittance was measured at 410 nm using UV3100PC (manufactured by Shimadzu Corporation). Thereafter, the orthogonal transmittance after storage for 1000 hours in an environment of 60 ° C. and 90% relative humidity was measured by the above method. The evaluation value of the polarizing plate durability was defined as follows and evaluated by the following determination. A rating or B rating is preferred, and A rating is more preferred.
Evaluation value of polarizing plate durability = [orthogonal transmittance after time (%) − orthogonal transmittance before time (%)] / orthogonal transmittance before time (%)
A: 0-4
B: More than 4 and not more than 8 C: More than 8 The obtained results are shown in Table 5 below.

(Reworkability evaluation)
A sample (about 24 cm × 16 cm) in which the cell-side surface of the polarizing plate prepared above was bonded to a glass plate with an adhesive (SK-2057: Soken Chemical Co., Ltd.) was prepared. When the bonded polarizing plate was peeled from the glass, it was evaluated by the following judgment from the area of the transparent support remaining on the glass. A rating or B rating is preferred, and A rating is more preferred.
A: No remaining area B: Remaining area is 5 cm ² or less C: Remaining area exceeds 5 cm ^{2 The} obtained results are shown in Table 5 below.

(Pencil hardness)
The pencil hardness evaluation described in JIS K5400 was performed. After conditioning the polarizing plates of Examples and Comparative Examples at a temperature of 25 ° C. and a relative humidity of 60% for 2 hours, using a test pencil of F to 5H defined in JIS S6006, at a load of 4.9 N, the following As the evaluation value, the highest hardness that results in OK was used as the evaluation value. The evaluation was made as follows. A rating or B rating is practically necessary, and A rating is preferred.
OK: No scratch in evaluation of n = 5 to two scratches NG: Three or more scratches in evaluation of n = 5 A: 2H or more B: H or more C: F or less The results obtained are shown in Table 5 below. .

(Viewing angle color evaluation)
(1) Mounting on a liquid crystal display device From a commercially available liquid crystal television (IPS-mode slim type 42-inch liquid crystal television, Δnd = 320 nm), the polarizing plate sandwiching the liquid crystal cell is peeled off, and the produced polarizing plate is adhered. It re-bonded to the liquid crystal cell through the agent.
(2) Measurement and evaluation of viewing angle color change Each of the produced liquid crystal display devices is displayed in black, and a color luminance meter (BM manufactured by Topcon Co., Ltd.) -5) was used to calculate the blackness change amount Δu′v ′. Evaluation was made according to the following criteria by Δu′v ′ calculated when the azimuth angle direction was changed in increments of 0 to 360 ° and 15 ° in the polar angle direction of 60 ° from the normal direction. A rating is preferred.
A: 0.15 or less B: Greater than 0.15 The results obtained are shown in Table 5 below.

(Warp unevenness evaluation)
The liquid crystal display device manufactured in the same manner as described above was thermosed at 60 ° C. and 90% relative humidity for 48 hours, and left at 25 ° C. and 60% relative humidity for 2 hours, and then the backlight of the liquid crystal display device was turned on. After 10 hours, light leakage at the four corners of the panel was evaluated to evaluate warp unevenness.
The light leakage evaluation was performed by photographing a black display screen from the front of the screen with a luminance measurement camera “ProMetric” (Radian Imaging), based on the average luminance of the entire screen and the luminance difference between the four corners where light leakage is large. Thus, the following criteria were used for evaluation. It is practically necessary to be A evaluation, B evaluation or C evaluation, preferably A evaluation or B evaluation, and more preferably A evaluation.
A: The light leakage at the four corners of the panel is not visually recognized (light leakage from the panel is about the same as before the thermo-injection).
B: Among the four corners of the panel, slight light leakage is visible at one or two corners, but is acceptable.
C: Among the four corners of the panel, slight light leakage is visible at 3 to 4 corners, but is acceptable.
D: Strong light leakage at the four corners of the panel.
The obtained results are shown in Table 5 below.

From Table 4 and Table 5 above, the polarizing plate of the present invention is a thin film, and the outer surface of the outer polarizing plate has a high pencil hardness. ) Was found to be small.
On the other hand, the polarizing plate of Comparative Example 1 in which the cellulose acylate film and the cycloolefin polymer layer are laminated in this order on the polarizer has a low Knoop hardness when a hard coat layer is provided outside the outer polarizing plate, and the outer polarizing plate. Was found to have a low pencil hardness.
The polarizing plate of Comparative Example 2 having a low Knoop hardness of the cellulose acylate film provided on the polarizer has a low Knoop hardness when the hard coat layer is provided outside the outer polarizing plate, and the pencil hardness of the outer polarizing plate is low. I understood it.
The polarizing plate of Comparative Example 3 in which the Knoop hardness of the cellulose acylate film provided on the polarizer is low and the total thickness of the polarizing plate exceeds the upper limit defined in the present invention is low in the pencil hardness of the outer polarizing plate, and the wet heat It was found that many light leaks (warp unevenness) occurred at the corners of the panel over time.
The polarizing plate of Comparative Example 4 in which the thickness of the entire polarizing plate greatly exceeds the upper limit specified in the present invention is found to cause a large amount of light leakage (warp unevenness) at the corners of the panel when it is incorporated into a liquid crystal display device and subjected to wet heat. It was.

1 Polarizer A One surface A of the polarizer
B The other side of the polarizer B
2A Cycloolefin polymer layer 2B disposed on the surface A side Second cycloolefin polymer layer 3A disposed on the surface B side Cellulose acylate film 3B disposed on the surface A side Second disposed on the surface B side Cellulose acylate film 4A Layer 4B formed by polymerizing ethylenically unsaturated monomer disposed on surface A side Layer 5 formed by polymerizing ethylenically unsaturated monomer disposed on surface B side Arranged on surface B side Other layers other than cellulose acylate film 10 Hard coat layer

Claims (16)

A polarizer,
A cycloolefin polymer layer disposed on one side A of the polarizer;
Cellulose acylate film in this order,
The thickness is 100 μm or less,
A polarizing plate characterized in that the Knoop hardness of the cellulose acylate film disposed on the surface A side of the polarizer is 240 N / mm ² or more. A polarizer,
A cycloolefin polymer layer disposed on one side A of the polarizer;
Cellulose acylate film in this order,
The thickness is 100 μm or less,
A polarizing plate having a Knoop hardness of 265 N / mm ² or more when a hard coat layer is laminated on the cellulose acylate film disposed on the surface A side of the polarizer.   The polarizing plate according to claim 1 or 2, wherein the cellulose acylate film disposed on the surface A side of the polarizer has a thickness of 35 µm or less.   The polarizing plate as described in any one of Claims 1-3 with which the 2nd cellulose acylate film was arrange | positioned further in the surface B side on the opposite side to the said surface A of the said polarizer.   The polarizing plate according to claim 4, wherein a second cycloolefin polymer layer is further disposed between the surface B of the polarizer and the second cellulose acylate film.   The polarizing plate according to claim 4 or 5, wherein a layer obtained by further polymerizing an ethylenically unsaturated monomer is disposed between the surface B of the polarizer and the second cellulose acylate film.   A layer formed by polymerizing an ethylenically unsaturated monomer and a second cycloolefin polymer layer are arranged in this order between the surface B of the polarizer and the second cellulose acylate film. Item 7. The polarizing plate according to any one of Items 4 to 6.   The polarizing plate according to claim 5, wherein a thickness of the second cycloolefin polymer layer disposed on the surface B side of the polarizer is 15 μm or less.   The polarizing plate according to claim 4, wherein Rth of the second cellulose acylate film disposed on the surface B side of the polarizer is −10 to 10 nm. Represents thickness direction retardation).   The layer formed by superposing | polymerizing an ethylenically unsaturated monomer is further arrange | positioned between the said cycloolefin polymer layer arrange | positioned at the said surface A side of the said polarizer, and the said polarizer. The polarizing plate as described in a term.   The polarizing plate according to claim 1, wherein a thickness of the cycloolefin polymer layer disposed on the surface A side of the polarizer is 15 μm or less.   The polarizing plate as described in any one of Claims 1-11 with which the hard-coat layer was further arrange | positioned on the said cellulose acylate film arrange | positioned at the said surface A side of the said polarizer.   The polarizing plate according to claim 1, wherein the polarizer has a thickness of 15 μm or less.   The polarizing plate according to claim 1, wherein the polarizing plate has a thickness of less than 80 μm.   A liquid crystal display device comprising at least one liquid crystal cell and at least one polarizing plate according to claim 1.   The polarizing plate such that the cycloolefin polymer layer disposed on the surface A side of the polarizer is closer to the liquid crystal cell than the cellulose acylate film disposed on the surface A side of the polarizer. The liquid crystal display device according to claim 15, wherein:

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