JP2005274943A - Method for manufacturing protective film for polarizing plate, protective film for polarizing plate, polarizing plate and liquid crystal display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate having less point defects with high yield and to provide a liquid crystal display apparatus having high display quality. <P>SOLUTION: The method for manufacturing a protective film for a polarizing plate is characterized in that a thermoplastic resin film is immersed in a high alkaline aqueous solution containing an antioxidant to carry out saponification. The invention presents a protective film for a polarizing plate obtained by the above method, and a polarizing plate and a liquid crystal display apparatus. The high alkaline aqueous solution preferably contains a surfactant. The thermoplastic resin film is preferably a cellulose acylate film containing 0.1 to 30 mass% of a low molecular weight compound having 200 to 1,000 molecular weight. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polarizing plate protective film, a manufacturing method thereof, a polarizing plate, and a liquid crystal display device.

Liquid crystal display devices are increasingly used year by year as space-saving image display devices with low power consumption. Conventionally, the large viewing angle dependence of images has been a major drawback of liquid crystal display devices, but in recent years, high viewing angle liquid crystal modes such as VA mode and IPS mode have been put into practical use. The demand for liquid crystal display devices is rapidly expanding even in markets where viewing angles are required.
Along with this, further improvements in quality and productivity have been demanded for polarizing plates used in liquid crystal display devices.
Currently, as a polarizing plate for a liquid crystal display device, it is common to use a polarizer obtained by stretching a polyvinyl alcohol film dyed with iodine and a polarizing plate protective film bonded from both sides. As a polarizing plate protective film, a film obtained by saponifying a cellulose acylate film to make the surface hydrophilic and imparting affinity with a polyvinyl alcohol film is widely used.
However, these polarizing plates have a problem that the yield is low with many surface defects such as point defects and spots. On the other hand, Patent Documents 1 and 2 disclose methods for improving the surface state of a polarizing plate by reducing surface failure during the production of a cellulose acylate film. However, even with these methods, surface improvement has been insufficient.

JP 2003-119297 A JP 2003-221455 A

An object of the present invention is to provide a polarizing plate with few point defects and high yield.
Another object of the present invention is to provide a liquid crystal display device with high display quality.

As a result of diligent research, the researchers of the present invention have found that the components eluted from the cellulose acylate film in the saponification step are further altered and become insoluble in water, and remain on the protective film and bonded to the polarizer. As a result, it was found that a point defect or a spot-like surface failure occurred, and it was found that the above problem can be solved by suppressing the generation of the insoluble component and / or effectively cleaning the generated insoluble component.
That is, the first aspect of the present invention relates to the following 1) manufacturing method.
1) A method for producing a polarizing plate protective film, comprising immersing a thermoplastic resin film in a highly alkaline aqueous solution containing an antioxidant and performing a saponification treatment.

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁹およびＲ¹⁰はそれぞれ独立に水素原子または置換基を表し、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴およびＲ⁵のうち少なくとも１つは電子供与性基を表し、Ｒ⁸は水素原子、炭素数１〜４のアルキル基、炭素数２〜６のアルケニル基、炭素数２〜６のアルキニル基、炭素数６〜１２のアリール基、炭素数１〜１２のアルコキシ基、炭素数６〜１２のアリールオキシ基、炭素数２〜１２のアルコキシカルボニル基、炭素数２〜１２のアシルアミノ基、シアノ基またはハロゲン原子を表す。）
９）下記一般式（３）で表される化合物を含有する６）〜８）いずれか１つに記載の偏光板保護フィルム、

一般式（３）
上記一般式（３）において、Ｒ¹はアルキル基またはアリール基を表し、Ｒ²は、アルキル基またはアリール基を表す。
１０）セルロースアシレートフィルムが１．０５以上２．００以下の延伸倍率で延伸されている６）〜９）いずれか１つに記載の偏光板保護フィルム、
１１）光学補償機能を有する６）〜１０）いずれか１つに記載の偏光板保護フィルム、 Preferred embodiments 2) to 5) are listed below.
2) A method for producing a polarizing plate protective film according to 1), wherein the highly alkaline aqueous solution contains a surfactant,
3) The method for producing a polarizing plate protective film according to 1) or 2), wherein the thermoplastic resin film is a cellulose acylate film containing 0.1 to 30% by mass of a low molecular compound having a molecular weight of 200 or more and 1,000 or less,
4) The cellulose acylate film contains 1 to 30% by mass or more of a compound having a molecular weight of 200 or more and 1,000 or less that decomposes in an aqueous alkali solution to produce a decomposition product soluble in the aqueous alkali solution. A method for producing a polarizing plate protective film according to any one of the above,
5) The cellulose acylate film contains at least one dissociable group having a pKa of 8 or more and 14 or less, and contains 1 to 30% by mass of a low molecular compound having a molecular weight of 200 or more and 1,000 or less. A method for producing a polarizing plate protective film according to claim 1,
6) Polarizing plate protective film and its embodiments 7) to 11), 12) polarizing plate, and 13) liquid crystal display device according to the second aspect related to 1) are as follows.
6) A polarizing plate protective film produced by the method according to any one of 1) to 5),
7) The polarizing plate protective film according to 6), wherein the substitution degree of cellulose acylate and the low molecular weight compound having a molecular weight of 200 or more and 1,000 or less satisfy the following relationship:
0 <Ao / Ai <1
0 ≦ Ro / Ri ≦ 0.9
Ao: degree of acylation of cellulose acylate in a region having a depth of 0.1 μm or less from the surface Ai: degree of acylation of cellulose acylate in a region having a depth of 2 μm or more from the surface Ro: depth from the surface Abundance of low molecular compounds in a region having a thickness of 0.1 μm or less Ri: abundance of low molecular compounds in a region having a depth of 2 μm or more from the surface 8) containing a compound represented by the following general formula (1) The polarizing plate protective film of 6) or 7) description.
General formula (1)

(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent, and R ¹ , R ² , R ³ , R ⁴ and R ⁵ each represents an electron donating group, and R ⁸ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. Group, aryl group having 6 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, aryloxy group having 6 to 12 carbon atoms, alkoxycarbonyl group having 2 to 12 carbon atoms, acylamino group having 2 to 12 carbon atoms, cyano Represents a group or a halogen atom.)
9) The polarizing plate protective film as described in any one of 6) -8) containing the compound represented by following General formula (3),

General formula (3)
In the general formula (3), R ¹ represents an alkyl group or an aryl group, and R ² represents an alkyl group or an aryl group.
10) The polarizing plate protective film according to any one of 6) to 9), wherein the cellulose acylate film is stretched at a stretch ratio of 1.05 to 2.00.
11) The polarizing plate protective film according to any one of 6) to 10) having an optical compensation function,

12) A polarizing plate in which a protective film is bonded to both sides of a polarizer, wherein at least one of the protective films is the polarizing plate protective film according to any one of 6) to 11). Polarizing plate,
13) A liquid crystal display device having a liquid crystal cell and two polarizing plates disposed on both sides thereof, wherein at least one polarizing plate is the polarizing plate described in 12).

  According to the present invention, it is possible to provide a polarizing plate with less yield of point defects and unevenness and high yield. Furthermore, by using the polarizing plate of the present invention for a liquid crystal display device, a liquid crystal display device with high display quality can be provided without causing problems such as light leakage.

(Polarizing plate protective film)
The polarizing plate of the present invention is a polarizing plate having a total of two protective films, one on each side of the polarizer, and at least one of the protective films is a polarizing plate using the protective film of the present invention. When using the polarizing plate of this invention for a liquid crystal display device, it is preferable that at least one of the two polarizing plates arrange | positioned at the both sides of a liquid crystal cell is a polarizing plate of this invention.

The manufacturing method of the polarizing plate protective film of this invention is characterized by immersing a thermoplastic resin film in the highly alkaline aqueous solution containing antioxidant, and performing a saponification process.
The antioxidant and the highly alkaline aqueous solution used for the saponification treatment will be described later.
The protective film used in the present invention is preferably a polymer film produced from norbornene resin, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, polyarylate, polysulfone, cellulose acylate, etc., and is a cellulose acylate film. It is more preferable.

[Cellulose acylate]
The cellulose acylate used in the present invention will be described.
The degree of substitution of cellulose acylate means the proportion of acylation of three hydroxyl groups present in cellulose structural units (glucose having β1 → 4 glycosidic bonds). The degree of substitution can be calculated by measuring the amount of bound fatty acid per unit weight of cellulose. The measurement method is carried out according to ASTM-D817-91.
The cellulose acylate of the present invention preferably has an acetylation degree of 2.7 to 3.0 and does not have an acyl group having 3 or more carbon atoms. The degree of acetylation is more preferably 2.75 or more and 2.95 or less.

Furthermore, in the present invention, it is also preferable to use cellulose acylate having an acylation degree of 1 or more and 2.9. The degree of acylation is more preferably from 1.7 to 2.7, and most preferably from 2.0 to 2.5. The average carbon number of the acyl group is preferably 2 or more and 7 or less, more preferably 2.05 or more and 5 or less, and most preferably 2.6 or more and 4 or less.
The acyl group preferably has 2 to 6 carbon atoms, and more preferably an acetyl group, a propionyl group, or a butyryl group. When the cellulose acylate film used in the present invention has an acetyl group and other acyl groups, the degree of substitution of the acetyl group is preferably less than 2.5, more preferably less than 1.9, and less than 1.1. Most preferred.

  The cellulose acylate of the present invention preferably has a weight average degree of polymerization of 350 to 800, more preferably a weight average degree of polymerization of 370 to 600. The cellulose acylate of the present invention preferably has a number average molecular weight of 70,000 to 230,000, more preferably a number average molecular weight of 75,000 to 230,000, and 78,000 to 120,000. Most preferably, it has a number average molecular weight of

  The cellulose acylate of the present invention can be synthesized using an acid anhydride or acid chloride as an acylating agent. When the acylating agent is an acid anhydride, an organic acid (eg, acetic acid) or methylene chloride is used as a reaction solvent. As the catalyst, a protic catalyst such as sulfuric acid is used. When the acylating agent is an acid chloride, a basic compound is used as a catalyst. In the most common synthetic method in the industry, cellulose is an organic acid corresponding to acetyl group and other acyl groups (acetic acid, propionic acid, butyric acid) or their acid anhydrides (acetic anhydride, propionic anhydride, butyric anhydride). A cellulose ester is synthesized by esterification with a mixed organic acid component containing. In this method, cellulose such as cotton linter and wood pulp is activated with an organic acid such as acetic acid, and then esterified using a mixture of organic acid components as described above in the presence of a sulfuric acid catalyst. There are many cases to do. The organic acid anhydride component is generally used in an excess amount relative to the amount of hydroxyl groups present in the cellulose. In this esterification treatment, a hydrolysis reaction (depolymerization reaction) of the cellulose main chain β1 → 4 glycoside bond) proceeds in addition to the esterification reaction. When the hydrolysis reaction of the main chain proceeds, the degree of polymerization of the cellulose ester is lowered, and the physical properties of the cellulose ester film to be produced are lowered. Therefore, the reaction conditions such as the reaction temperature must be determined in consideration of the degree of polymerization and molecular weight of the resulting cellulose ester.

  In order to obtain a cellulose ester having a high degree of polymerization (high molecular weight), it is important to adjust the maximum temperature in the esterification reaction step to 50 ° C. or lower. The maximum temperature is preferably adjusted to 35 to 50 ° C, more preferably 37 to 47 ° C. If the reaction temperature is less than 35 ° C., the esterification reaction may not proceed smoothly. When the reaction temperature exceeds 50 ° C., the degree of polymerization of the cellulose ester tends to decrease. After the esterification reaction, when the reaction is stopped while suppressing a temperature rise, a decrease in the degree of polymerization can be further suppressed, and a cellulose ester having a high degree of polymerization can be synthesized. That is, when a reaction terminator (eg, water, acetic acid) is added after completion of the reaction, excess acid anhydride that has not participated in the esterification reaction is hydrolyzed to form a corresponding organic acid as a by-product. This hydrolysis reaction is accompanied by intense heat generation, and the temperature in the reactor rises. When the rate of addition of the reaction terminator is high, heat is rapidly generated exceeding the cooling capacity of the reactor. Therefore, the hydrolysis reaction of the cellulose main chain proceeds remarkably, and the polymerization degree of the resulting cellulose ester is lowered. In addition, a part of the catalyst is bonded to the cellulose during the esterification reaction, and most of the catalyst is dissociated from the cellulose during the addition of the reaction terminator. However, when the rate of addition of the reaction terminator is high, there is not enough reaction time for the catalyst to dissociate, and a part of the catalyst remains in a state of being bound to cellulose. Cellulose esters to which a strong acid catalyst is partially bonded are very poor in stability, and are easily decomposed by heat during drying of the product to lower the degree of polymerization. For these reasons, after the esterification reaction, the reaction is preferably stopped by adding a reaction terminator over a period of preferably 4 minutes or more, more preferably 4 to 30 minutes. In addition, when the addition time of the reaction terminator exceeds 30 minutes, industrial productivity decreases. As the reaction terminator, water or alcohol that decomposes an acid anhydride is generally used. However, in the present invention, a mixture of water and an organic acid is preferably used as a reaction terminator in order not to precipitate triesters having low solubility in various organic solvents. When the esterification reaction is carried out under the above conditions, a high molecular weight cellulose ester having a weight average polymerization degree of 500 or more can be easily synthesized.

[Hydrophobic agent]
Next, a low molecular weight compound having a molecular weight of 1,000 or less (hereinafter also referred to as “hydrophobizing agent”) used in the present invention will be described.
The low molecular weight compound has a molecular weight of 1,000 or less, but preferably has a molecular weight of 200 or more and 1,000 or less.
As the hydrophobizing agent used in the present invention, a hydrophobizing agent having a depth of within 0.1 μm from the film surface is preferably removed by alkali saponification treatment. One preferred example of a hydrophobizing agent having such characteristics is to use a hydrophobizing agent that is easily decomposed by alkali and the decomposition product elutes in the saponification solution. As such a hydrophobizing agent, a compound having at least one ester bond in the molecule is preferable.

Among these, the compound represented by the following general formula (1) is particularly preferable because it has a large hydrophobizing effect and is excellent in compatibility with cellulose acylate.
These compounds are described in detail below.
General formula (1)

(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent, and R ¹ , R ² , R ³ , R ⁴ and R ⁵ each represents an electron donating group, wherein R ⁸ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or an aryl having 6 to 12 carbon atoms. A group, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom.

In general formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent, and the substituent will be described later. The substituent T can be applied.
At least one of R ¹ , R ² , R ³ , R ⁴ and R ⁵ represents an electron donating group. Preferably, one of R ¹ , R ³ or R ⁵ is an electron donating group, and R ³ is more preferably an electron donating group.

The electron-donating group is one having a Hammett σ _p value of O or less. Rev. 91, 165 (1991). Those having a Hammet's σ _p value of not more than O can be preferably applied, and those having −0.85 to 0 are more preferably used. Examples thereof include an alkyl group, an alkoxy group, an amino group, and a hydroxyl group.
The electron donating group is preferably an alkyl group or an alkoxy group, more preferably an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly preferably carbon). 1 to 4).

R ¹ is preferably a hydrogen atom or an electron donating group, more preferably an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, and still more preferably an alkyl group having 1 to 4 carbon atoms or a carbon number 1 to 12 Particularly preferably an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). Most preferred is a methoxy group.

R ² is preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group or a hydroxyl group, more preferably a hydrogen atom, an alkyl group or an alkoxy group, still more preferably a hydrogen atom or an alkyl group (preferably a carbon number). 1 to 4, more preferably a methyl group), an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to carbon atoms). 4). Particularly preferred are a hydrogen atom, a methyl group, and a methoxy group.

R ³ is preferably a hydrogen atom or an electron donating group, more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, still more preferably an alkyl group or an alkoxy group, particularly preferably. An alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). Most preferred are n-propoxy group, ethoxy group, and methoxy group

R ⁴ is preferably a hydrogen atom or an electron donating group, more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, and still more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. , An alkoxy group having 1 to 12 carbon atoms (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms), particularly preferably. Is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and most preferably a hydrogen atom, a methyl group, or a methoxy group.

Preferred groups for R ⁵ are the same as those listed for R ² .

R ⁶ , R ⁷ , R ⁹ and R ¹⁰ are preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a halogen atom, more preferably a hydrogen atom or a halogen atom. More preferably a hydrogen atom.

R ⁸ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryloxy having 6 to 12 carbon atoms. Group, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom, which may have a substituent if possible. The group T can be applied.

R ⁸ is preferably an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryloxy group having 2 to 12 carbon atoms. And more preferably an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms (preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms), and particularly preferably a methoxy group, an ethoxy group, and n. -A propoxy group, an iso-propoxy group, and an n-butoxy group.

Of the general formula (1), the following general formula (1-A) is more preferable.
Formula (1-A)

(Wherein R ¹¹ represents an alkyl group. R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represents a hydrogen atom or a substituent. R ⁸ Is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, (Represents an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom.)
In the general formula (1-A), R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are respectively synonymous with those in the general formula (1), and The preferable range is also the same.

In general formula (1-A), R ¹¹ represents an alkyl group, and the alkyl group represented by R ¹¹ may be linear or branched, and may further have a substituent, An alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms, and particularly preferably an alkyl group having 1 to 4 carbon atoms (for example, a methyl group or an ethyl group). , N-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group and the like).

Of the general formula (1), the following general formula (1-B) is more preferable.
Formula (1-B)

(Wherein R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represents a hydrogen atom or a substituent. R ¹¹ is an alkyl having 1 to 12 carbon atoms. X represents an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms. A group, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom.)

In general formula (1-B), R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ have the same meanings as those in general formula (1), and the preferred ranges are also the same. It is.
In general formula (1-B), R ¹¹ has the same meaning as those in general formula (1-A), and the preferred range is also the same.

In general formula (1-B), X is an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and 6 carbon atoms. Represents an aryloxy group having 12 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom.
When all of R ¹ , R ² , R ⁴ and R ⁵ are hydrogen atoms, X is preferably an alkyl group, alkynyl group, aryl group, alkoxy group or aryloxy group, more preferably an aryl group or alkoxy group. And an aryloxy group, more preferably an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). And particularly preferably a methoxy group, a methoxy group, an n-propoxy group, an iso-propoxy group or an n-butoxy group.

When at least one of R ¹ , R ² , R ⁴ and R ⁵ is a substituent, X is preferably an alkynyl group, aryl group, alkoxycarbonyl group or cyano group, more preferably an aryl group (preferably 6 to 12 carbon atoms), a cyano group, and an alkoxycarbonyl group (preferably 2 to 12 carbon atoms), more preferably an aryl group (preferably an aryl group having 6 to 12 carbon atoms, more preferably a phenyl group, p-cyanophenyl group and p-methoxyphenyl group), alkoxycarbonyl group (preferably having 2 to 12 carbon atoms, more preferably having 2 to 6 carbon atoms, still more preferably having 2 to 4 carbon atoms, particularly preferably methoxycarbonyl, Ethoxycarbonyl, n-propoxycarbonyl), cyano group, particularly preferably phenyl group, methoxycarbonyl. Boniru group, an ethoxycarbonyl group, n- propoxycarbonyl group, a cyano group.

Of the general formula (1), the following general formula (1-C) is more preferable.
Formula (1-C)

(In the formula (1-C), R ¹ , R ² , R ⁴ , R ⁵ , R ¹¹ and X have the same meanings as those in the general formula (1-B), and preferred ranges are also the same.)

Among the compounds represented by the general formula (1), a compound represented by the following general formula (1-D) is preferable.
Formula (1-D)

(In formula (1-D), R ² , R ⁴ and R ⁵ have the same meanings as those in formula (1-C), and preferred ranges are also the same. R ²¹ and R ²² are each independently carbon. X ¹ is an aryl group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, or a cyano group.

R ²¹ represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, and more preferably an ethyl group or a methyl group.
R ²² represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably an ethyl group or a methyl group, and still more preferably a methyl group.

X ¹ is an aryl group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, or a cyano group, preferably an aryl group having 6 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, or a cyano group. More preferably a phenyl group, a p-cyanophenyl group, a p-methoxyphenyl group, a methoxycarbonyl, an ethoxycarbonyl, an n-propoxycarbonyl, a cyano group, and still more preferably a phenyl group, a methoxycarbonyl group, an ethoxycarbonyl group, n-propoxycarbonyl group and cyano group.

Of the general formula (1), the following general formula (1-E) is most preferable.
Formula (1-E)

(In the formula (1-E), R ² , R ⁴ and R ⁵ have the same meanings as those in the general formula (1-D), and preferred ranges are also the same, but one of them is represented by —OR ^13. (R ¹³ is an alkyl group having 1 to 4 carbon atoms.) R ²¹ , R ²² and X ¹ have the same meanings as those in formula (1-D), and preferred ranges are also the same. is there.)

In general formula (1-E), R ² , R ^4, and R ⁵ have the same meanings as those in general formula (1-D), and preferred ranges are also the same, but one of them is represented by —OR ^13. (R ¹³ is an alkyl group having 1 to 4 carbon atoms), preferably R ⁴ and R ⁵ are groups represented by —OR ¹³ , more preferably R ⁴ is —OR ¹³ . It is a group represented.
R ¹³ represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably an ethyl group or a methyl group, and still more preferably a methyl group.

The aforementioned substituent T will be described below.
Examples of the substituent T include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms such as methyl, ethyl, iso-propyl, tert-butyl, and n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2-8, for example, propargyl, 3-pentynyl, etc.), aryl groups (preferably having 6-30 carbon atoms) More preferably, it has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl and the like, and a substituted or unsubstituted amino group (preferably having 0 to 0 carbon atoms). 20, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc.), an alkoxy group (preferably having a carbon number) 1 to 20, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy, etc.), an aryloxy group (preferably 6 to 20 carbon atoms, more Preferably it has 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 2-naphthyloxy and the like. An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, and pivaloyl). An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, etc.), an aryloxycarbonyl group ( Preferably it has 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, and examples thereof include phenyloxycarbonyl, etc.), an acyloxy group (preferably 2 to 20 carbon atoms, More preferably, it has 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms. Nzoyloxy and the like. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino), alkoxycarbonylamino group (Preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino), aryloxycarbonylamino group (preferably having carbon number) 7 to 20, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino, and the like, and sulfonylamino groups (preferably 1 to 20 carbon atoms, more preferably Has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. , Benzenesulfonylamino, etc.), alkylsulfamoyl group or arylsulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms). For example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl, etc.), carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably carbon 1 to 12, for example, carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), an alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably carbon number). 1 to 12, for example, methylthio, ethylthio, etc. An arylthio group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio), an alkylsulfonyl group or an arylsulfonyl group A group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as mesyl, tosyl, etc.), an alkylsulfinyl group or an arylsulfinyl group (preferably Has 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably 1 to 20 carbon atoms). More preferably, it has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. And methylureido, phenylureido and the like. ), Phosphoric acid amide groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as diethyl phosphoric acid amide and phenylphosphoric acid amide. ), Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, Heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidyl , Morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), Group (preferably, 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, e.g., trimethylsilyl, etc. triphenylsilyl and the like) and the like. These substituents may be further substituted.

  Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

  Hereinafter, the compound represented by the general formula (1) will be described in detail with specific examples, but the present invention is not limited to the following specific examples.

The compound represented by the general formula (1) of the present invention can be synthesized by a general ester reaction of a substituted benzoic acid and a phenol derivative, and any reaction may be used as long as it is an ester bond forming reaction. Examples thereof include a method of converting a substituted benzoic acid to an acid halide and then condensing with phenol, a method of dehydrating the substituted benzoic acid and a phenol derivative using a condensing agent or a catalyst, and the like.
In view of the production process and the like, a method in which the substituted benzoic acid is functionally converted to an acid halide and then condensed with phenol is preferable.

  Reaction solvents include hydrocarbon solvents (preferably toluene and xylene), ether solvents (preferably dimethyl ether, tetrahydrofuran, dioxane, etc.), ketone solvents, ester solvents, acetonitrile, dimethylformamide, dimethyl Acetamide or the like can be used. These solvents may be used alone or in admixture of several kinds, and preferred reaction solvents are toluene, acetonitrile, dimethylformamide and dimethylacetamide.

The reaction temperature is preferably 0 to 150 ° C, more preferably 0 to 100 ° C, still more preferably 0 to 90 ° C, and particularly preferably 20 ° C to 90 ° C.
In this reaction, it is preferable not to use a base. When a base is used, either an organic base or an inorganic base may be used, preferably an organic base such as pyridine, tertiary alkylamine (preferably triethylamine, ethyldiisopropyl). Pyramine and the like).

  The method for synthesizing the compound of the present invention is specifically described below, but the present invention is not limited by the following specific examples.

[Synthesis Example 1: Synthesis of Exemplified Compound A-1]
After heating 24.6 g (0.116 mol) of 3,4,5-trimethoxybenzoic acid, 100 mL of toluene and 1 mL of NN-dimethylformamide to 60 ° C., 15.2 g (0.127 mol) of thionyl chloride was slowly added. And then heated at 60 ° C. for 2 hours. Thereafter, a solution prepared by previously dissolving 15.1 g (0.127 mol) of 4-cyanophenol in 50 mL of acetonitrile was slowly added dropwise, and after completion of the addition, the mixture was heated and stirred at 60 ° C. for 3 hours. After cooling the reaction solution to room temperature, liquid separation operation was performed with ethyl acetate and water. After removing water from the obtained organic phase with sodium sulfate, the solvent was distilled off under reduced pressure. 100 mL was added and recrystallization operation was performed. The acetonitrile solution was cooled to room temperature, and the precipitated crystals were collected by filtration to obtain 11.0 g (yield 11%) of the target compound as white crystals. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.

¹ H-NMR (CDCl ₃ ) δ 3.50 (br, 9H), 7.37 (d, 2H), 7.45 (s, 2H), 7.77 (s, 2H)
Mass spectrum: m / z 314 (M + H) ⁺
The melting point of the obtained compound was 172 to 173 ° C.

[Synthesis Example 2: Synthesis of Exemplified Compound A-2]
After heating 106.1 g (0.5 mol) of 2,4,5-trimethoxybenzoic acid, 340 mL of toluene and 1 mL of dimethylformamide to 60 ° C., 65.4 g (0.55 mol) of thionyl chloride was slowly added dropwise, Heated at 65-70 ° C. for 2 hours. Thereafter, a solution prepared by previously dissolving 71.5 g (0.6 mol) of 4-cyanophenol in 150 mL of acetonitrile was slowly added dropwise. After completion of the addition, the mixture was heated and stirred at 80 to 85 ° C. for 2 hours. After cooling the reaction solution to room temperature, liquid separation operation was performed with ethyl acetate (1 L) and water. After removing water from the obtained organic phase with magnesium sulfate, about 500 mL of the solvent was distilled off under reduced pressure, and 1 L of methanol was added. And recrystallization operation was performed. The precipitated crystals were collected by filtration to obtain 125.4 g (yield 80%) of the target compound as white crystals. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.

¹ H-NMR (CDCl ₃ ) δ 3.91 (s, 3H), 3.93 (s, 3H), 3.98 (s, 3H), 6.59 (s, 1H), 7.35 (d, 2H), 7.58 (s, 1H), 7.74 (d, 2H)
Mass spectrum: m / z 314 (M + H) ⁺
The melting point of the obtained compound was 116 ° C.

[Synthesis Example 3: Synthesis of Exemplified Compound A-3]
After heating 10.1 g (47.5 mmol) of 2,3,4-trimethoxybenzoic acid, 40 mL of toluene and 0.5 mL of dimethylformamide to 80 ° C., 6.22 g (52.3 mmol) of thionyl chloride was slowly added dropwise. And stirred at 80 ° C. for 2 hours. Thereafter, a solution prepared by previously dissolving 6.2 g (52.3 mmol) of 4-cyanophenol in 20 mL of acetonitrile was slowly added dropwise. After completion of the addition, the mixture was heated and stirred at 80 to 85 ° C. for 2 hours. After cooling the reaction solution to room temperature, liquid separation operation was performed with ethyl acetate and water. After removing water from the obtained organic phase with sodium sulfate, the solvent was distilled off under reduced pressure, 50 mL of methanol was added, and recrystallization operation was performed. Went. The precipitated crystals were collected by filtration to obtain 11.9 g (yield 80%) of the target compound as white crystals. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.

¹ H-NMR (CDCl ₃ ): δ 3.50 (br, 9H), 7.37 (d, 2H), 7.45 (s, 2H), 7.77 (s, 2H)
Mass spectrum: m / z 314 (M + H) ⁺
The melting point of the obtained compound was 102 to 103 ° C.

[Synthesis Example 4: Synthesis of Exemplary Compound A-4]
After heating 25.0 g (118 mmol) of 2,4,6-trimethoxybenzoic acid, 100 mL of toluene and 1 mL of dimethylformamide to 60 ° C., 15.4 g (129 mmol) of thionyl chloride was slowly added dropwise, Stir for hours. Thereafter, a solution prepared by previously dissolving 15.4 g (129 mmol) of 4-cyanophenol in 50 mL of acetonitrile was slowly added dropwise. After completion of the addition, the mixture was heated and stirred at 80 to 85 ° C. for 4.5 hours. After cooling the reaction solution to room temperature, liquid separation operation was performed with ethyl acetate and water. After removing water from the obtained organic phase with sodium sulfate, the solvent was distilled off under reduced pressure, and 500 mL of methanol and 100 mL of acetonitrile were added, Recrystallization operation was performed. The precipitated crystals were collected by filtration to obtain 10.0 g (yield 27%) of the target compound as white crystals. The compound was identified by mass spectrum.
Mass spectrum: m / z 314 (M + H) ⁺
The melting point of the obtained compound was 172 to 173 ° C.

[Synthesis Example 5: Synthesis of Exemplary Compound A-5]
After heating 15.0 g (82.3 mmol) of 2,3-dimethoxybenzoic acid, 60 mL of toluene and 0.5 mL of dimethylformamide to 60 ° C., 10.7 (90.5 mmol) of thionyl chloride was slowly added dropwise. The mixture was heated and stirred at 60 ° C. for 2 hours. Thereafter, a solution prepared by previously dissolving 10.8 g (90.5 mmol) of 4-cyanophenol in 30 mL of acetonitrile was slowly added dropwise, and after completion of the addition, the mixture was heated and stirred at 70 to 80 ° C. for 7 hours. After cooling the reaction solution to room temperature, 90 mL of isopropyl alcohol was added, and the precipitated crystals were collected by filtration to obtain 12.3 g (yield 53%) of the target compound as white crystals. The compound was identified by mass spectrum.

Mass spectrum: m / z 284 (M + H) ⁺
The melting point of the obtained compound was 104 ° C.

[Synthesis Example 6: Synthesis of Exemplified Compound A-6]
The synthesis was performed in the same manner except that 2,3-dimethoxybenzoic acid in A-5 was changed to 2,4-dimethoxybenzoic acid. The compound was identified by mass spectrum.
Mass spectrum: m / z 284 (M + H) ⁺
The melting point of the obtained compound was 134 to 136 ° C.

[Synthesis Example 7: Synthesis of Exemplified Compound A-7]
After heating 25.0 g (137 mmol) of 2,5-dimethoxybenzoic acid, 100 mL of toluene and 1.0 mL of dimethylformamide to 60 ° C., 18.0 (151 mmol) of thionyl chloride was slowly added dropwise. Stir for hours. Thereafter, a solution prepared by previously dissolving 18.0 g (151 mmol) of 4-cyanophenol in 50 mL of acetonitrile was slowly added dropwise. After completion of the addition, the mixture was heated and stirred at 70 to 80 ° C. for 7.5 hours. After cooling the reaction solution to room temperature, liquid separation operation was performed with ethyl acetate and saturated brine, and water was removed from the obtained organic phase with sodium sulfate. Then, the solvent was distilled off under reduced pressure, and silica gel column chromatography (hexane -Purification operation with ethyl acetate (9/1, V / V)) yielded 18.8 g (yield 48%) of the target compound as white crystals. The compound was identified by mass spectrum.

Mass spectrum: m / z 284 (M + H) ⁺
The melting point of the obtained compound was 79-80 ° C.

[Synthesis Example 8: Synthesis of Exemplary Compound A-8]
The synthesis was performed in the same manner except that 2,3-dimethoxybenzoic acid in A-5 was changed to 2,6-dimethoxybenzoic acid. The compound was identified by mass spectrum.
Mass spectrum: m / z 284 (M + H) ⁺
The melting point of the obtained compound was 130 to 131 ° C.

[Synthesis Example 9: Synthesis of Exemplary Compound A-11]
The target compound was obtained in the same manner except that 71.5 g of 4-cyanophenol in A-2 was changed to 76.9 g of 4-chlorophenol. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.

¹ H-NMR (CDCl ₃ ) δ 3.90 (s, 3H), 3.94 (s, 3H), 3.99 (s, 3H), 6.58 (s, 1H), 7.15 (d, 2H), 7.37 (d, 2H), 7.56 (s, 1H)
Mass spectrum: m / z 323 (M + H) ⁺
The melting point of the obtained compound was 127 to 129 ° C.

[Synthesis Example 10: Synthesis of Exemplified Compound A-12]
After heating 45.0 g (212 mmol) of 2,4,5-trimethoxybenzoic acid, 180 mL of toluene and 1.8 mL of dimethylformamide to 60 ° C., 27.8 g (233 mmol) of thionyl chloride was slowly added dropwise to the mixture at 60 ° C. And stirred for 2.5 hours. Thereafter, a solution prepared by dissolving 35.4 g (233 mmol) of methyl 4-hydroxybenzoate in 27 mL of dimethylformamide was slowly added, and the mixture was heated and stirred at 80 ° C. for 3 hours. 270 mL was added, and the precipitated crystals were collected by filtration to obtain 64.5 g (yield 88%) of the target compound as white crystals. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.

¹ H-NMR (CDCl ₃ ) δ 3.95 (m, 9H), 3.99 (s, 3H), 6.57 (s, 1H), 7.28 (d, 2H), 7.57 (s, 1H) 8.11 (d, 2H)
Mass spectrum: m / z 347 (M + H) ⁺
The melting point of the obtained compound was 121 to 123 ° C.

[Synthesis Example 11: Synthesis of Exemplary Compound A-13]
After heating 20.0 g (94.3 mmol) of 2,4,5-trimethoxybenzoic acid, 100 mL of toluene and 1 mL of dimethylformamide to 60 ° C., 12.3 g (104 mmol) of thionyl chloride was slowly added dropwise to the mixture at 60 ° C. And stirred for 3.5 hours. Thereafter, a solution in which 17.7 g (104 mmol) of 4-phenylphenol was dissolved in 150 mL of toluene was slowly added, and the mixture was heated and stirred at 80 ° C. for 3 hours. The reaction solution was then cooled to room temperature, and 250 mL of methanol was added. The precipitated crystals were collected by filtration to obtain 21.2 g (yield 62%) of the target compound as white crystals. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.

¹ H-NMR (CDCl ₃ ) δ 3.93 (s, 3H), 3.96 (s, 3H), 3.99 (s, 3H), 6.59 (s, 1H), 7.26-7. 75 (m, 10H)
Mass spectrum: m / z 365 (M + H) ⁺
The melting point of the obtained compound was 131-132 ° C.

[Synthesis Example 12: Synthesis of Exemplified Compound A-14]
After heating 12.9 g (61 mmol) of 2,4,5-trimethoxybenzoic acid, 50 mL of toluene, and 0.6 mL of dimethylformamide to 60 ° C., 8.0 g (67 mmol) of thionyl chloride was slowly added dropwise to the mixture at 60 ° C. And stirred for 3.5 hours. Thereafter, a solution prepared by dissolving 17.7 g (104 mmol) of 4-phenylphenol in 25 mL of acetonitrile was slowly added and stirred at 80 ° C. for 3 hours. The reaction solution was then cooled to room temperature, and 100 mL of methanol was added. The precipitated crystals were collected by filtration to obtain 21.6 g (yield 93%) of the target compound as white crystals. The compound was identified by mass spectrum.
Mass spectrum: m / z 381 (M + H) ⁺
The melting point of the obtained compound was 91-92 ° C.

[Synthesis Example 13: Synthesis of Exemplary Compound A-15]
The target compound was obtained in the same manner except that 71.5 g of 4-cyanophenol in A-2 was changed to 56.4 g of phenol. The compound was identified by ¹ H-NMR and mass spectrum.

¹ H-NMR (CDCl ₃ ) δ 3.91 (s, 3H), 3.93 (s, 3H), 3.99 (s, 3H), 6.58 (s, 1H), 7.19-7. 27 (m, 3H), 7.42 (m, 2H)
7.58 (s, 1H)
Mass spectrum: m / z 365 (M + H) ⁺
The melting point of the obtained compound was 105 to 108 ° C.
Mass spectrum: m / z 289 (M + H) ⁺

[Synthesis Example 14: Synthesis of Exemplified Compound A-16]
The target compound can be obtained in the same manner except that 71.5 g of 4-cyanophenol in A-2 is changed to 74.4 g of 4-methoxyphenol. The compound was identified by ¹ H-NMR and mass spectrum.

¹ H-NMR (CDCl ₃ ) δ 3.84 (s, 3H), 3.92 (s, 3H), 3.93 (s, 3H), 3.99 (s, 3H), 6.58 (s, 1H), 6.92 (d, 2H), 7.12 (d, 2H), 7.42 (m, 2H), 7.58 (s, 1H)
Mass spectrum: m / z 319 (M + H) ⁺
The melting point of the obtained compound was 102 to 103 ° C.

[Synthesis Example 15: Synthesis of Exemplified Compound A-17]
The target compound was obtained in the same manner except that 71.5 g of 4-cyanophenol in A-2 was changed to 73.3 g of 4-ethylphenol. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.
Mass spectrum: m / z 317 (M + H) ⁺
The melting point of the obtained compound was 70 to 71 ° C.

[Synthesis Example 16: Synthesis of Exemplary Compound A-24]
After heating 27.3 g (164 mmol) of 4-ethoxybenzoic acid, 108 mL of toluene, and 1 mL of dimethylformamide to 60 ° C., 21.5 g (181 mmol) of thionyl chloride was slowly added dropwise and stirred at 60 ° C. for 2 hours. . Thereafter, a solution in which 25.0 g (181 mmol) of 4-ethoxyphenol was previously dissolved in 50 mL of acetonitrile was slowly added, and the mixture was heated and stirred at 80 ° C. for 4 hours. After cooling the reaction solution to room temperature, 100 mL of methanol was added. The precipitated crystals were collected by filtration to obtain 30.6 g (yield 65%) of the target compound as white crystals. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.

¹ H-NMR (CDCl ₃ ) δ 1.48-1.59 (m, 6H), 4.05 (q, 2H), 4.10 (q, 2H), 6.89-7.00 (m, 4H) ), 7.10 (d, 2H), 8.12 (d, 2H)
Mass spectrum: m / z 287 (M + H) ⁺
The melting point of the obtained compound was 113 to 114 ° C.

[Synthesis Example 17: Synthesis of Exemplified Compound A-25]
After heating 24.7 g (149 mmol) of 4-ethoxybenzoic acid, 100 mL of toluene and 1 mL of dimethylformamide to 60 ° C., 19.5 g (164 mmol) of thionyl chloride was slowly added dropwise, and the mixture was heated and stirred at 60 ° C. for 2 hours. . Thereafter, a solution prepared by dissolving 25.0 g (165 mmol) of 4-propoxyphenol in 50 mL of acetonitrile was slowly added, and the mixture was heated and stirred at 80 ° C. for 4 hours. After cooling the reaction solution to room temperature, 100 mL of methanol was added. The precipitated crystals were collected by filtration, 100 mL of methanol was added to the obtained solid, and recrystallization was performed. The obtained crystals were collected by filtration to obtain 33.9 g (yield 76%) of the target compound as white crystals. It was. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.

¹ H-NMR (CDCl ₃ ) δ 1.04 (t, 3H), 1.45 (t, 3H), 1.82 (q, 2H), 3.93 (q, 2H), 4.04 (q, 2H), 6.89-7.00 (m, 4H), 7.10 (d, 2H), 8.12 (d, 2H)
Mass spectrum: m / z 301 (M + H) ⁺
The melting point of the obtained compound was 107 ° C.

[Synthesis Example 18: Synthesis of Exemplified Compound A-27]
The compound was synthesized in the same manner except that 27.3 g of 4-ethoxybenzoic acid in the synthesis method of A-24 was changed to 29.5 g of 4-propoxybenzoic acid. The compound was identified by mass spectrum.
Mass spectrum: m / z 301 (M + H) ⁺
The melting point of the obtained compound was 88-89 ° C.

[Synthesis Example 19: Synthesis of Exemplary Compound A-28]
The compound was synthesized in the same manner except that 24.7 g of 4-ethoxybenzoic acid in the synthesis method of A-25 was changed to 26.8 g of 4-propoxybenzoic acid. The compound was identified by mass spectrum.
Mass spectrum: m / z 315 (M + H) ⁺
The melting point of the obtained compound was 92 ° C.

[Synthesis Example 20: Synthesis of Exemplified Compound A-40]
After heating 20.0 g (109 mmol) of 2,4-dimethoxybenzoic acid, 80 mL of toluene, and 0.8 mL of dimethylformamide to 60 ° C., 14.4 g (121 mmol) of thionyl chloride was slowly added dropwise, The mixture was heated and stirred for 5 hours. Thereafter, a solution prepared by previously dissolving 20.5 g (121 mmol) of 4-phenylphenol in 50 mL of dimethylformamide was slowly added and stirred at 80 ° C. for 6 hours. After cooling the reaction solution to room temperature, 100 mL of methanol was added. In addition, the precipitated crystals were collected by filtration to obtain 31.7 g (yield 86%) of the target compound as white crystals. The compound was identified by mass spectrum.
Mass spectrum: m / z 335 (M + H) ⁺
The melting point of the obtained compound was 161-162 ° C.

[Synthesis Example 21: Synthesis of Exemplified Compound A-42]
After heating 30.0 g (165 mmol) of 2,4-dimethoxybenzoic acid, 120 mL of toluene, and 1.2 mL of dimethylformamide to 60 ° C., 21.6 g (181 mmol) of thionyl chloride was slowly added dropwise. Stir for hours. Thereafter, a solution prepared by dissolving 27.6 g (181 mmol) of methyl 4-hydroxyhydroxybenzoate in 40 mL of dimethylformamide was slowly added, and the mixture was heated and stirred at 80 ° C. for 6 hours. Methanol (140 mL) was added, and the precipitated crystals were collected by filtration to obtain 24.4 g (yield 47%) of the target compound as white crystals. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.
¹ H-NMR (CDCl ₃ ) δ 3.92 (m, 9H), 6.56 (m, 2H), 7.27 (m, 2H), 8.09 (m, 3H)

Mass spectrum: m / z 317 (M + H) ⁺
The melting point of the obtained compound was 122-123 ° C.

(Aliphatic polyhydric alcohol)
The following aliphatic polyhydric alcohol esters can also be preferably used as the hydrophobizing agent of the present invention. The aliphatic polyhydric alcohol ester of the present invention is an ester of a dihydric or higher aliphatic polyhydric alcohol and one or more monocarboxylic acids.

The aliphatic polyhydric alcohol used in the present invention is a dihydric or higher alcohol represented by the following general formula (2).
R ^1- (OH) _n ... General formula (2)
R ¹ represents an n-valent aliphatic organic group, n represents a positive integer of 2 or more, and an OH group represents an alcoholic and / or phenolic hydroxyl group.

  Examples of the n-valent aliphatic organic group include an alkylene group (eg, methylene group, ethylene group, trimethylene group, tetramethylene group, etc.), an alkenylene group (eg, ethenylene group, etc.), an alkynylene group (eg, ethynylene group, etc.), a cycloalkylene group. (For example, 1,4-cyclohexanediyl group) and alkanetriyl group (for example, 1,2,3-propanetriyl group). The n-valent aliphatic organic group includes those having a substituent (for example, a hydroxy group, an alkyl group, a halogen atom, etc.).

  n is preferably from 2 to 20. Examples of preferable polyhydric alcohol include, for example, adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1 , 2-butanediol, 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, Examples thereof include galactitol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol and the like. In particular, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, and xylitol are preferable.

(Monocarboxylic acid)
There is no restriction | limiting in particular as monocarboxylic acid in the polyhydric alcohol ester of this invention, Well-known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, etc. can be used. Use of an alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferred in terms of improving moisture permeability and retention.

  Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or side chain having 1 to 32 carbon atoms can be preferably used. The number of carbon atoms is more preferably 1-20, and particularly preferably 1-10. When acetic acid is contained, compatibility with the cellulose ester is increased, and it is also preferable to use a mixture of acetic acid and another monocarboxylic acid.

  Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid , Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, undecylenic acid, Examples thereof include unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid. These may further have a substituent.

  Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof.

  Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid, and tetralincarboxylic acid. The aromatic monocarboxylic acid which has, or those derivatives can be mentioned. Benzoic acid is particularly preferable.

(Polyhydric alcohol ester)
The molecular weight of the polyhydric alcohol ester used in the present invention is not particularly limited, but is preferably 300 to 1500, and more preferably 350 to 750. The larger one is preferable in terms of retention, and the smaller one is preferable in terms of moisture permeability and compatibility with the cellulose ester.

  The carboxylic acid in the polyhydric alcohol ester of the present invention may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are. Preferably, it has 3 or more aromatic rings or cycloalkyl rings in the molecule.

  Examples of the polyhydric alcohol ester used in the present invention are shown below.

Furthermore, alkylphthalyl alkyl glycolates can also be preferably used as the hydrophobizing agent of the present invention.
The alkyl in the alkylphthalylalkyl glycolate is an alkyl group having 1 to 8 carbon atoms. Examples of alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl ethyl glycolate, Ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, propyl phthalyl ethyl glycolate, methyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl Phthalyl ethyl glycolate, propyl phthalyl butyl glycolate, butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl Collate, octyl phthalyl methyl glycolate, octyl phthalyl ethyl glycolate and the like can be mentioned, methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, Octyl phthalyl octyl glycolate is preferable, and ethyl phthalyl ethyl glycolate is particularly preferably used.

In the present invention, a hydrophobizing agent having a functional group that dissociates in an alkali saponification solution (hereinafter referred to as “dissociable group”) can also be preferably used. Any dissociable group can be used as long as it is non-dissociable at a neutral pH and has low solubility in an aqueous alkaline solution, but dissociates at a high pH and significantly improves the solubility in an aqueous alkaline solution. . The acid dissociation constant (pKa) of the dissociable group is preferably 7 or more, more preferably 8 or more, and most preferably 9 or more.
Preferable functional groups as the dissociable group include phenol group, naphthol group, sulfonamide group, ureido group and the like.
Among these, as the hydrophobizing agent, it is preferable to use a low molecular compound having at least one dissociable group having a pKa of 8 or more and 14 or less and having a molecular weight of 1,000 or less.

As the hydrophobizing agent as described above, a compound represented by the following general formula (3) is particularly preferable.
General formula (3)

In the general formula (3), R ¹ represents an alkyl group or an aryl group, and R ² represents an alkyl group or an aryl group.
Moreover, it is particularly preferable that the total number of carbon atoms of R ¹ and R ² is 10 or more. As the substituent, a fluorine atom, an alkyl group, an aryl group, an alkoxy group, a sulfone group, and a sulfonamide group are preferable, and an alkyl group, an aryl group, an alkoxy group, a sulfone group, and a sulfonamide group are particularly preferable. Further, the alkyl group may be linear, branched or cyclic, and preferably has 1 to 25 carbon atoms, more preferably 6 to 25, and more preferably 6 to 20 (E.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, isoamyl, t-amyl, hexyl, cyclohexyl, heptyl, octyl, bicyclooctyl, nonyl, adamantyl, decyl, t-octyl, undecyl, Dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, didecyl) are particularly preferred. As the aryl group, those having 6 to 30 carbon atoms are preferable, and those having 6 to 24 carbon atoms (for example, phenyl, biphenyl, terphenyl, naphthyl, binaphthyl, triphenylphenyl) are particularly preferable. Further, the addition amount of the modifier of the present invention is preferably 2 to 30% by mass, more preferably 2 to 25% by mass, and more preferably 2 to 20% by mass with respect to cellulose acylate. Is particularly preferred. Preferred examples of the compound represented by the general formula (3) are shown below, but the present invention is not limited to these specific examples.

The low molecular weight compound having a molecular weight of 1,000 or less used in the present invention can have not only the function of a hydrophobizing agent but also other functions such as a retardation adjusting agent and a plasticizer.
The hydrophobizing agent of the present invention may be added to a cellulose acetate solution (dope) after being dissolved in an organic solvent such as alcohol, methylene chloride or dioxolane, or may be added directly to the dope composition.
The content of the hydrophobizing agent of the present invention relative to 100 parts by mass of cellulose acylate is preferably 0.1 to 30% by mass, more preferably 1 to 30% by mass, further preferably 3 to 25% by mass, and 5 to 20% by mass. Is most preferred.

The cellulose acylate film of the present invention may contain an ultraviolet absorber in addition to the hydrophobizing agent.
Examples of ultraviolet absorbers include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, etc., but less colored benzotriazole compounds Compounds are preferred. Further, ultraviolet absorbers described in JP-A-10-182621 and JP-A-8-337574 and polymer ultraviolet absorbers described in JP-A-6-148430 are also preferably used. When the cellulose acylate film of the present invention is used as a protective film for a polarizing plate, the ultraviolet absorber is excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less from the viewpoint of preventing deterioration of the polarizer and the liquid crystal, and the liquid crystal. From the viewpoint of display properties, those that absorb less visible light having a wavelength of 400 nm or more are preferred.

  Specific examples of the benzotriazole ultraviolet absorber useful in the present invention include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert). -Butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butyl Phenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl) benzotriazole, 2,2 -Methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2 ' Hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol Octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H-benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy Examples include, but are not limited to, a mixture of -5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate. As commercially available products, TINUVIN 109, TINUVIN 171, TINUVIN 326, and TINUVIN 328 (all manufactured by Ciba Specialty Chemicals) can be preferably used.

[Manufacture of cellulose acylate film]
The cellulose acylate film of the present invention can be produced by a solvent cast method. In the solvent cast method, a film is produced using a solution (dope) in which cellulose acylate is dissolved in an organic solvent.

[Organic solvent]
The organic solvent for dissolving cellulose acylate is an ether having 3 to 12 carbon atoms, a ketone having 3 to 12 carbon atoms, an ester having 3 to 12 carbon atoms, and a halogenation having 1 to 6 carbon atoms. It is preferable to include a solvent selected from hydrocarbons.
The ether, ketone and ester may have a cyclic structure. A compound having two or more functional groups of ether, ketone and ester (that is, —O—, —CO— and —COO—) can also be used as the organic solvent. The organic solvent may have another functional group such as an alcoholic hydroxyl group. In the case of an organic solvent having two or more kinds of functional groups, the number of carbon atoms is preferably within the above-described preferable range of carbon atoms of the solvent having any functional group.

Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole.
Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexanone.
Examples of the esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate.
Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.
The number of carbon atoms of the halogenated hydrocarbon is preferably 1 or 2, and most preferably 1. The halogen of the halogenated hydrocarbon is preferably chlorine. The proportion of halogen atoms substituted by halogen in the halogenated hydrocarbon is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and more preferably 35 to 65 mol%. More preferably, it is most preferable that it is 40-60 mol%. Methylene chloride is a representative halogenated hydrocarbon.
Two or more organic solvents may be mixed and used.

A cellulose acylate solution can be prepared by a general method comprising processing at a temperature of 0 ° C. or higher (ordinary temperature or high temperature). The solution can be prepared using a dope preparation method and apparatus in a normal solvent cast method. In the case of a general method, it is preferable to use a halogenated hydrocarbon (particularly methylene chloride) as the organic solvent.
The amount of cellulose acylate is adjusted so as to be contained in the obtained solution in an amount of 10 to 40% by mass. The amount of cellulose acylate is more preferably 10 to 30% by mass. Arbitrary additives described later may be added to the organic solvent (main solvent).

The solution can be prepared by stirring the cellulose acylate and the organic solvent at room temperature (0 to 40 ° C.). High concentration solutions may be stirred under pressure and heating conditions. Specifically, the cellulose acylate and the organic solvent are placed in a pressure vessel and sealed, and stirred while being heated to a temperature equal to or higher than the boiling point of the solvent at normal temperature and in a range where the solvent does not boil.
The heating temperature is usually 40 ° C. or higher, preferably 60 to 200 ° C., and more preferably 80 to 110 ° C.

Each component may be coarsely mixed in advance and then placed in a container. Moreover, you may put into a container sequentially. The container needs to be configured so that it can be stirred. The container can be pressurized by injecting an inert gas such as nitrogen gas. Moreover, you may utilize the raise of the vapor pressure of the solvent by heating. Or after sealing a container, you may add each component under pressure.
When heating, it is preferable to heat from the outside of the container. For example, a jacket type heating device can be used. The entire container can also be heated by providing a plate heater outside the container and piping to circulate the liquid.
It is preferable to provide a stirring blade inside the container and stir using this. The stirring blade preferably has a length that reaches the vicinity of the wall of the container. A scraping blade is preferably provided at the end of the stirring blade in order to renew the liquid film on the vessel wall.
Instruments such as a pressure gauge and a thermometer may be installed in the container. Each component is dissolved in a solvent in the container. The prepared dope is taken out of the container after cooling, or taken out and then cooled using a heat exchanger or the like.

A solution can also be prepared by a cooling dissolution method. In the cooling dissolution method, cellulose acylate can be dissolved in an organic solvent that is difficult to dissolve by a normal dissolution method. In addition, even if it is a solvent which can melt | dissolve a cellulose acylate with a normal melt | dissolution method, there exists an effect that a uniform solution can be obtained rapidly according to a cooling melt | dissolution method.
In the cooling dissolution method, first, cellulose acylate is gradually added to an organic solvent at room temperature while stirring. The amount of cellulose acylate is preferably adjusted so as to be contained in the mixture at 10 to 40% by mass. The amount of cellulose acylate is more preferably 10 to 30% by mass. Furthermore, you may add the arbitrary additive mentioned later in a mixture.

The mixture is then cooled to -100 to -10 ° C (preferably -80 to -10 ° C, more preferably -50 to -20 ° C, most preferably -50 to -30 ° C). The cooling can be performed, for example, in a dry ice / methanol bath (−75 ° C.) or a cooled diethylene glycol solution (−30 to −20 ° C.). The mixture of cellulose acylate and organic solvent is solidified by cooling.
The cooling rate is preferably 4 ° C./min or more, more preferably 8 ° C./min or more, and most preferably 12 ° C./min or more. The higher the cooling rate, the better. However, 10,000 ° C./second is the theoretical upper limit, 1,000 ° C./second is the technical upper limit, and 100 ° C./second is the practical upper limit. The cooling rate is a value obtained by dividing the difference between the temperature at the start of cooling and the final cooling temperature by the time from the start of cooling to the final cooling temperature.

Furthermore, when this is heated to 0 to 200 ° C. (preferably 0 to 150 ° C., more preferably 0 to 120 ° C., most preferably 0 to 50 ° C.), cellulose acylate dissolves in the organic solvent. The temperature may be increased by simply leaving it at room temperature or in a warm bath.
The heating rate is preferably 4 ° C./min or more, more preferably 8 ° C./min or more, and most preferably 12 ° C./min or more. The higher the heating rate, the better. However, 10,000 ° C./second is the theoretical upper limit, 1,000 ° C./second is the technical upper limit, and 100 ° C./second is the practical upper limit. . The heating rate is a value obtained by dividing the difference between the temperature at the start of heating and the final heating temperature by the time from the start of heating until the final heating temperature is reached. .
A uniform solution is obtained as described above. If the dissolution is insufficient, the cooling and heating operations may be repeated. Whether or not the dissolution is sufficient can be determined by merely observing the appearance of the solution with the naked eye.

In the cooling dissolution method, it is desirable to use a sealed container in order to avoid moisture mixing due to condensation during cooling. In the cooling and heating operation, if the pressure is applied during cooling and the pressure is reduced during heating, the dissolution time can be shortened. In order to perform pressurization and decompression, it is desirable to use a pressure-resistant container.
In addition, according to the measurement by a differential scanning calorimeter (DSC), the 20 mass% solution which melt | dissolved cellulose acetate (acetylation degree: 60.9%, viscosity average polymerization degree: 299) in methyl acetate by the cooling dissolution method is. In the vicinity of 33 ° C., there exists a quasi-phase transition point between a sol state and a gel state, and a uniform gel state is obtained below this temperature. Therefore, it is necessary to keep this solution at a temperature equal to or higher than the pseudo phase transition temperature, preferably about 10 ° C. plus the gel phase transition temperature. However, this pseudo phase transition temperature varies depending on the degree of acetylation of cellulose acetate, the degree of viscosity average polymerization, the concentration of the solution, and the organic solvent used.

A cellulose acylate film is produced from the prepared cellulose acylate solution (dope) by a solvent cast method. It is preferable to add a retardation increasing agent to the dope.
The dope is cast on a drum or band and the solvent is evaporated to form a film. The concentration of the dope before casting is preferably adjusted so that the solid content is 18 to 35%. The surface of the drum or band is preferably finished in a mirror state. The dope is preferably cast on a drum or band having a surface temperature of 10 ° C. or less.

  Regarding the drying method in the solvent cast method, U.S. Pat. Nos. 45-4554, 49-5614, JP-A-60-176834, JP-A-60-203430, and JP-A-62-115035. Drying on the band or drum can be performed by blowing an inert gas such as air or nitrogen.

  The obtained film can be peeled off from the drum or band and further dried with high-temperature air whose temperature is successively changed from 100 ° C. to 160 ° C. to evaporate the residual solvent. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, it is possible to shorten the time from casting to stripping. In order to carry out this method, it is necessary for the dope to gel at the surface temperature of the drum or band during casting.

  Two or more layers can be cast using the prepared cellulose acylate solution (dope) to form a film. In this case, it is preferable to produce a cellulose acylate film by a solvent cast method. The dope is cast on a drum or band and the solvent is evaporated to form a film. It is preferable to adjust the concentration of the dope before casting so that the solid content is in the range of 10 to 40%. The surface of the drum or band is preferably finished in a mirror state.

  When casting a plurality of cellulose acylate solutions of two or more layers, it is possible to cast a plurality of cellulose acylate solutions, from a plurality of casting openings provided at intervals in the direction of travel of the support. You may produce a film, casting and laminating the solution containing a cellulose acylate, respectively. For example, the methods described in JP-A-61-158414, JP-A-1-122419, and JP-A-11-198285 can be used. It can also be formed into a film by casting a cellulose acylate solution from two casting ports. For example, JP-B-60-27562, JP-A-61-94724, JP-A-61-947245, JP-A-61-104413, JP-A-61-158413, and JP-A-6-134933. The method described in each publication can be used. Further, a cellulose acylate film is disclosed in which a flow of a high-viscosity cellulose acylate solution described in JP-A-56-162617 is wrapped with a low-viscosity cellulose acylate solution and the high-low viscosity cellulose acylate solution is extruded simultaneously. A casting method can also be used.

Also, using two casting ports, the film formed on the support by the first casting port is peeled off, and the second casting is performed on the side that is in contact with the support surface to produce a film. You can also For example, the method described in Japanese Patent Publication No. 44-20235 can be mentioned.
As the cellulose acylate solution to be cast, the same solution may be used, or different cellulose acylate solutions may be used. In order to give a function to a plurality of cellulose acylate layers, a cellulose acylate solution corresponding to the function may be extruded from each casting port. Furthermore, the cellulose acylate solution of the present invention can be cast simultaneously with other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, an ultraviolet absorbing layer, a polarizing layer, etc.).

  In the conventional single-layer solution, it is necessary to extrude a cellulose acylate solution having a high concentration and a high viscosity in order to obtain a necessary film thickness. In such a case, the stability of the cellulose acylate solution is poor and solid matter is generated, which often causes problems due to defects or poor flatness. As a solution to this problem, by casting a plurality of cellulose acylate solutions from the casting port, it is possible to extrude a highly viscous solution onto the support at the same time, improving the flatness and improving the planar film. Not only can be produced, but also the use of a concentrated cellulose acylate solution can reduce the drying load and increase the production speed of the film.

  A degradation inhibitor (eg, antioxidant, peroxide decomposer, radical inhibitor, metal deactivator, acid scavenger, amine) may be added to the cellulose acylate film. The deterioration preventing agents are described in JP-A-3-199201, JP-A-51907073, JP-A-5-194789, JP-A-5-271471, and JP-A-6-107854. The addition amount of the deterioration preventing agent is preferably 0.01 to 1% by mass of the solution (dope) to be prepared, and more preferably 0.01 to 0.2% by mass. When the addition amount is less than 0.01% by mass, the effect of the deterioration preventing agent is hardly recognized. When the addition amount exceeds 1% by mass, bleed-out (bleeding) of the deterioration preventing agent to the film surface may be observed. Examples of particularly preferred deterioration inhibitors include butylated hydroxytoluene (BHT) and tribenzylamine (TBA).

  These steps from casting to post-drying may be performed in an air atmosphere or an inert gas atmosphere such as nitrogen gas. The winder used for the production of the cellulose acylate film used in the present invention may be a commonly used winder such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress. It can be wound up by a take-up method.

[Stretching treatment]
For the polarizing plate protective film of the present invention, a stretched cellulose acylate film can also be preferably used. A desired retardation can be imparted to the cellulose acylate film by the stretching treatment, and the cellulose acylate film can also have a function as a retardation film.
The stretching direction of the cellulose acylate film is preferably either the width direction or the longitudinal direction.

  Methods for stretching in the width direction are described in, for example, JP-A-62-115035, JP-A-4-152125, JP-A-2842211, JP-A-298310, and JP-A-11-48271. Yes. The film is stretched at room temperature or under heating conditions. The heating temperature is preferably not higher than the glass transition temperature of the film. The film can be stretched by a treatment during drying, and is particularly effective when the solvent remains. In the case of stretching in the longitudinal direction, for example, the film is stretched by adjusting the speed of the film transport roller so that the film winding speed is higher than the film peeling speed. In the case of stretching in the width direction, the film can also be stretched by conveying while holding the width of the film with a tenter and gradually widening the width of the tenter. After the film is dried, it can be stretched using a stretching machine (preferably uniaxial stretching using a long stretching machine). The draw ratio of the film is preferably 1.05 to 2.00 times, more preferably 1.10 times to 1.80 times.

[Saponification]
The polarizing plate protective film of the present invention can be produced by immersing a cellulose acylate film containing the hydrophobizing agent in a highly alkaline aqueous solution containing an antioxidant and subjecting it to an alkali saponification treatment.
Hereinafter, the alkali saponification treatment will be specifically described.
The alkali saponification treatment of the cellulose acetate film is preferably carried out in a cycle in which the film surface is immersed in a highly alkaline solution (hereinafter referred to as saponification solution), neutralized with an acidic solution, washed with water and dried.
Examples of the highly alkaline solution include potassium hydroxide solution and sodium hydroxide solution. In the present invention, the highly alkaline solution is an alkaline solution having a prescribed concentration of hydroxide ions in the range of 0.05 to 5.0 N, preferably in the range of 0.1 to 3.0 N, and More preferably, it is in the range of 5 to 2.0N.
The alkaline solution temperature is preferably in the range of room temperature to 90 ° C, and more preferably in the range of 40 to 70 ° C.

[Antioxidant]
The saponification solution of the present invention preferably contains an antioxidant. As the antioxidant, both inorganic compounds and organic compounds can be preferably used.
Inorganic compounds such as sulfites (eg, sodium sulfite, potassium sulfite, ammonium sulfite, etc.), bisulfites (eg, ammonium bisulfite, sodium bisulfite, potassium bisulfite, etc.), metabisulfites (eg, metabisulfite) Sulfite ion releasing compounds such as potassium sulfite, sodium metabisulfite, ammonium metabisulfite, etc.) are preferred. These compounds are preferably contained in an amount of about 0.02 to 0.05 mol / liter in terms of sulfite ion, and more preferably 0.04 to 0.40 mol / liter.

Examples of the organic compound include hydroxyl groups such as diethylhydroxylamine, N, N-dimethoxyethylhydroxylamine, N, N-disulfoethylhydroxylamine, N, Ndicarboxyethylhydroxylamine, N, N-diphosphonoethylhydroxylamine and the like. Amine derivatives, hydrazines such as N, N-dicarboxymethylhydrazine, sulfoethylhydrazine, sulfopropylhydrazine, alkanolamines such as triethanolamine, diethanolamine, catechol-3,5-disulfonic acid, catechol-3,5 Catechols such as 6-trisulfonic acid can be preferably used.
The amount of these antioxidants added is preferably 0.1 g to 30 g, more preferably 0.5 to 15 g per liter of saponification solution.

[Surfactant]
The saponification liquid used in the present invention preferably contains a surfactant.
As the water-soluble surfactant used in the present invention, various surfactants such as anion, nonion, cation and betaine can be used. Specifically, JP-A-1-150136, pages 63 to 71, The compounds described in JP-A-4-194451, pages 7 to 14 can be used. Among these, nonionic surfactants represented by the following general formula are particularly preferably used.
Formula (II)

式中、Ｒ^２１は水素原子、アルキル基、アルケニル基、アリール基またはアルキルカルボニル基を表わし、Ｌ_１およびＬ_３はエチレンオキシ基、Ｌ_２はプロピレンオキシ基を表わす。ｐ、ｑ、ｒは各々０〜３００の整数を表わし、ｐ＋ｑ＋ｃは５以上である。Ｒ^２１は好ましくは、炭素数６〜２０の直鎖もしくは分岐したアルキル基またはアルケニル基、フェニル基、炭素数１〜１８の直鎖もしくは分岐したアルキル基で置換されたフェニル基または炭素数５〜２０のアルキルカルボニル基を表わす。ｐ、ｑ、ｒは好ましくは各々０〜１００の整数を表わし、ｐ＋ｑ＋ｒは５以上である。またｐ＋ｑ＋ｒは好ましくは３００以下である。一般式（ＩＩ）で表わされる化合物の具体例を以下に示すが、本発明はこれら化合物に限定されるものではない。

In the formula, R ²¹ represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or an alkylcarbonyl group, L ₁ and L ₃ represent an ethyleneoxy group, and L ₂ represents a propyleneoxy group. p, q, and r each represent an integer of 0 to 300, and p + q + c is 5 or more. R ²¹ is preferably a linear or branched alkyl group or alkenyl group having 6 to 20 carbon atoms, a phenyl group, a phenyl group substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, or 5 to 5 carbon atoms. Represents 20 alkylcarbonyl groups. p, q and r each preferably represents an integer of 0 to 100, and p + q + r is 5 or more. Further, p + q + r is preferably 300 or less. Specific examples of the compound represented by formula (II) are shown below, but the present invention is not limited to these compounds.

Among these compounds, compounds having a surfactant HLB value (Hydrophile-Lipophile Balance, balance between hydrophilicity and hydrophobicity) quantified by Griffin are preferably 9 to 15. A compound having an HLB value of 11 to 13 is particularly preferably used because it has no liquid turbidity and has a large effect of reducing stain. For details on the HLB value, see J.H. Soc. Cosmetic Chem. 1, 311 (1949), 5,249 (1954), and J. Org. T.A. Davis and E.M. K. Rideal, “Interfacial Phenomena”, Academic Press, New York (1961), page 366. In addition, as described in Yoshio Koda "Organic Conceptual Diagram-Fundamentals and Applications", Sankyo Publishing Co., Ltd. (1986), pages 88-91, the ratio of inorganic to organic (I / O) was calculated, and the value was calculated. A value obtained by multiplying x by 10 can be substituted. In addition, compounds represented by the following general formula (IV) are also preferably used.
Formula (IV)

In the formula, R ⁴¹ represents an alkyl group, an alkenyl group, an aryl group or an alkylcarbonyl group. n and m each represents an integer of 0 to 100, and n + m is 2 or more. M represents an alkali metal (Na, K, Li).
R ⁴¹ is preferably a linear or branched alkyl group having 6 to 20 carbon atoms or an alkenyl group, a phenyl group, a phenyl group substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, or a carbon number of 5 to 5 Represents 20 alkylcarbonyl groups. n and m preferably represent an integer of 0 to 50. Specific examples of the compound represented by formula (IV) are shown below, but the present invention is not limited to these compounds.

  When using these water-soluble surfactants, the amount added may be an amount that effectively produces the action, and is not particularly limited, but is preferably 0.1 g to 30 g / liter, More preferably, it is 0.5g-20g / liter, Especially preferably, it is 1g-10g / liter. Further, the pH of the developer when these are used is preferably 8 to 12, and more preferably 9 to 11.

The surface energy of a solid can be determined by a contact angle method, a wet heat method, and an adsorption method as described in “Basics and Applications of Wetting” (issued by Realize 1989.12.10). In the case of the cellulose acetate film of the present invention, the contact angle method is preferably used.
Specifically, two types of solutions having known surface energies are dropped on a cellulose acetate film, and at the intersection of the surface of the droplet and the surface of the film, the angle between the tangent line drawn on the droplet and the surface of the film The surface angle of the film can be calculated by defining the angle containing the droplet as the contact angle.

The degree of substitution of cellulose acylate in the cellulose acylate film after saponification treatment preferably satisfies the following relationship.
0 <Ao / Ai <1
Ao: Degree of acylation of cellulose acylate in the region where the depth from the surface is within 0.1 μm Ai: Degree of acylation of cellulose acylate in the region where the depth from the surface is 2 μm or more, more preferably 0 <Ao /Ai<0.9, more preferably 0 <Ao / Ai <0.8.
The abundance of low molecular weight compounds having a molecular weight of 200 or more and 1,000 or less in the cellulose acylate film after saponification treatment preferably satisfies the following relationship.
0 ≦ Ro / Ri ≦ 0.9
Ro: abundance of a low molecular compound in a region having a depth of 0.1 μm or less from the surface Ri: abundance of a low molecular compound in a region having a depth of 2 μm or more from the surface, more preferably 0 ≦ Ro / Ri ≦ 0 0.7, and more preferably 0 ≦ Ro / Ri ≦ 0.5.

  Changes in the degree of acylation of cellulose acylate and the amount of low molecular weight compounds in the depth direction of the film were determined by cutting the film diagonally at an angle of 1 ° with respect to the film surface, It can be determined by mapping fragment ion intensity or molecular ion intensity with a secondary ion mass spectrometer (TOF-SIMS).

[Thickness of cellulose acylate film]
The thickness of the cellulose acylate film of the present invention is preferably 10 μm to 200 μm, more preferably 20 μm to 150 μm, and most preferably 30 μm to 100 μm.

[Moisture content of cellulose acylate film]
The moisture content of the cellulose acylate film can be evaluated by measuring the equilibrium moisture content at a constant temperature and humidity. The equilibrium moisture content is calculated by measuring the moisture content of the sample that has reached equilibrium after being left at the temperature and humidity for 24 hours by the Karl Fischer method and dividing the moisture content (g) by the sample mass (g). .
The water content at 25 ° C. and 80% RH of the cellulose acylate film of the present invention is preferably 5.0% by mass or less, more preferably 4.3% by mass or less, and further preferably 3.8% by mass or less. Most preferred.

[Moisture permeability]
The moisture permeability is calculated as the amount of moisture (g) that evaporates in 24 hours per 1 m ^{2 of} area by measuring the moisture permeability of each sample in accordance with the method described in JIS Z 0208. The moisture permeability is a film property closely related to the durability of the polarizing plate, and the durability of the polarizing plate can be improved by reducing the moisture permeability. The cellulose acylate film of the present invention preferably has a moisture permeability at 60 ℃ 95% RH24hr is 1700 g / m ² or less 200 g / m ² or more. More preferably, it is 500 or more and 1400 or less.

[Film retardation]
The Re retardation value and Rth retardation value of the film are defined by the following formulas (I) and (II), respectively.
(I) Re = (nx−ny) × d
(II) Rth = {(nx + ny) / 2−nz} × d
In the formulas (I) and (II), nx is the refractive index in the slow axis direction (direction in which the refractive index is maximum) in the film plane.
In formulas (I) and (II), ny is the refractive index in the fast axis direction (the direction in which the refractive index is minimized) in the film plane.
In formula (II), nz is the refractive index in the thickness direction of the film.
In the formulas (I) and (II), d is the thickness of the film whose unit is nm.

[Polarizer]
The cellulose acylate film of the present invention is used as a protective film for a polarizing plate, and can be particularly preferably used as a retardation film corresponding to various liquid crystal modes.
In the polarizing plate in which the protective film is bonded to both sides of the polarizer, it is preferable that at least one of the protective films is the polarizing plate protective film of the present invention.

When the cellulose acylate film of the present invention is used as a retardation film, preferred optical properties of the cellulose acylate film vary depending on the liquid crystal mode.
For the OCB mode, Re is preferably 10 to 100, more preferably 20 to 70. Rth is preferably from 50 to 300, more preferably from 100 to 250.
For the VA mode, Re is preferably 20 to 100, more preferably 30 to 70. Rth is preferably 50 to 250, more preferably 80 to 180.
For TN, Re is preferably 0-50, more preferably 2-30. Rth is preferably 10-200, more preferably 30-150.
In the OCB mode and the TN mode, an optically anisotropic layer can be applied on the cellulose acylate film having the retardation value and used as an optical compensation film.

  In addition, it is preferable that the birefringence ((DELTA) n: nx-ny) of a cellulose acylate film exists in the range of 0.00-0.002 micrometer. The birefringence {(nx + ny) / 2-nz} in the thickness direction of the support film and the counter film is preferably in the range of 0.00 to 0.04.

[Photoelasticity]
The photoelastic coefficient of the cellulose acylate of the present invention is preferably 60 × 10 ⁻⁸ cm ² / N or less, and more preferably 20 × 10 ⁻⁸ cm ² . The photoelastic coefficient can be determined by an ellipsometer.
[Glass-transition temperature]
The glass transition temperature of the cellulose acylate of the present invention is preferably 120 ° C. or higher, more preferably 140 ° C. or higher. The glass transition temperature is a temperature at which the baseline derived from the glass transition of the film begins to change and a temperature at which the glass returns to the baseline again when measured at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC). Is obtained as an average value of.

(Configuration of polarizing plate)
Next, a polarizer used for the polarizing plate of the present invention will be described.
The polarizing plate of this invention may have an adhesive layer, a separate film, and a protective film as a component other than a polarizer and a protective film.

[Polarizer]
The polarizer of the present invention is preferably composed of polyvinyl alcohol (PVA) and a dichroic molecule. However, as described in JP-A-11-248937, PVA and polyvinyl chloride are dehydrated and dechlorinated. Polyvinylene-based polarizers in which a polyene structure is generated and oriented can also be used.

PVA is a polymer material obtained by saponifying polyvinyl acetate, but may contain components copolymerizable with vinyl acetate such as unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, and vinyl ethers. . In addition, modified PVA containing an acetoacetyl group, a sulfonic acid group, a carboxyl group, an oxyalkylene group, or the like can also be used.
The saponification degree of PVA is not particularly limited, but is preferably 80 to 100 mol%, particularly preferably 90 to 100 mol% from the viewpoint of solubility and the like. The degree of polymerization of PVA is not particularly limited, but is preferably 1000 to 10,000, and particularly preferably 1500 to 5000.
The syndiotacticity of PVA is preferably 55% or more for improving durability as described in Japanese Patent No. 2978219, but 45 to 52.5% described in Japanese Patent No. 3317494 is also preferably used. it can.

After PVA is formed into a film, it is preferable to introduce a dichroic molecule to constitute a polarizer. As a method for producing a PVA film, a method of forming a film by casting a stock solution obtained by dissolving a PVA resin in water or an organic solvent is generally preferably used. The density | concentration of the polyvinyl alcohol-type resin in a stock solution is 5-20 mass% normally, and a PVA film with a film thickness of 10-200 micrometers can be manufactured by forming this stock solution with a casting method. The PVA film can be produced with reference to Japanese Patent No. 3342516, Japanese Patent Application Laid-Open No. 09-328593, Japanese Patent Application Laid-Open No. 2001-302817, and Japanese Patent Application Laid-Open No. 2002-144401.
The degree of crystallinity of the PVA film is not particularly limited. However, in order to reduce the average crystallinity (Xc) of 50 to 75% by mass described in Japanese Patent No. 3251073 and in-plane hue variation, Japanese Patent Application Laid-Open No. 2002-2005 A PVA film having a crystallinity of 38% or less described in No. 236214 can be used.

The birefringence (Δn) of the PVA film is preferably small, and a PVA film having a birefringence of 1.0 × 10 ⁻³ or less described in Japanese Patent No. 3342516 can be preferably used. However, as described in JP-A-2002-228835, in order to obtain a high degree of polarization while avoiding cutting during stretching of the PVA film, the birefringence of the PVA film may be set to 0.02 or more and 0.01 or less. Alternatively, as described in JP-A-2002-060505, the value of (nx + ny) / 2-nz may be 0.0003 or more and 0.01 or less. The retardation (in-plane) of the PVA film is preferably from 0 nm to 100 nm, and more preferably from 0 nm to 50 nm. Moreover, 0 nm or more and 500 nm or less are preferable, and, as for Rth (film thickness direction) of a PVA film, 0 nm or more and 300 nm or less are more preferable.

In addition, the polarizing plate of the present invention includes a PVA film having a 1,2-glycol bond amount of 1.5 mol% or less described in Japanese Patent No. 3021494, 5 μm or more described in JP-A No. 2001-316492. PVA film having 500 or less optical foreign matter per 100 cm ² , PVA film having a hot water cutting temperature spot of 1.5 ° C. or less in the TD direction of the film described in JP-A-2002-030163, and glycerin Preferred is a PVA film formed from a solution in which 1 to 100 parts by mass of a trivalent to hexavalent polyhydric alcohol such as 1 to 100 parts by mass or a plasticizer described in JP-A 06-289225 is mixed in an amount of 15% by mass or more. Can be used.

  Although the film thickness before extending | stretching of a PVA film is not specifically limited, 1 micrometer-1 mm are preferable and 20-200 micrometers is especially preferable from a viewpoint of stability of film holding | maintenance and the uniformity of extending | stretching. As described in JP-A-2002-236212, a thin PVA film in which the stress generated when stretching 4 to 6 times in water is 10 N or less may be used.

Dichroic molecule I ₃ ^- or I ₅ ^- can be preferably used an iodine ion or a dichroic dye higher such. In the present invention, higher-order iodine ions are particularly preferably used. Higher-order iodine ions can be found in “Applications of Polarizing Plates” by Ryo Nagata, CMC Publishing and Industrial Materials, Vol. 28, No. 7, p. 39-p. As described in 45, PVA can be produced by immersing PVA in a solution obtained by dissolving iodine in an aqueous potassium iodide solution and / or an aqueous boric acid solution and adsorbing and orienting the PVA.

  When a dichroic dye is used as the dichroic molecule, an azo dye is preferable, and a bisazo dye and a trisazo dye are particularly preferable. The dichroic dye is preferably a water-soluble dye. For this reason, a hydrophilic substituent such as a sulfonic acid group, an amino group or a hydroxyl group is introduced into the dichroic molecule, so that a free acid, an alkali metal salt, an ammonium salt or an amine is introduced. It is preferably used as a salt.

  Specific examples of such dichroic dyes include C.I. I. Direct Red 37, Congo Red (C.I. Direct Red 28), C.I. I. Direct Violet 12, C.I. I. Direct Blue 90, C.I. I. Direct Blue 22, C.I. I. Direct Blue 1, C.I. I. Direct Blue 151, C.I. I. Benzidines such as Direct Green 1, C.I. I. Direct Yellow 44, C.I. I. Direct Red 23, C.I. I. Diphenylurea such as Direct Red 79, C.I. I. Stilbene series such as Direct Yellow 12, C.I. I. Dinaphthylamine type such as Direct Red 31, C.I. I. Direct Red 81, C.I. I. Direct Violet 9, C.I. I. Mention may be made of J acid systems such as Direct Blue 78.

  In addition, C.I. I. Direct Yellow 8, C.I. I. Direct Yellow 28, C.I. I. Direct Yellow 86, C.I. I. Direct Yellow 87, C.I. I. Direct Yellow 142, C.I. I. Direct Orange 26, C.I. I. Direct Orange 39, C.I. I. Direct Orange 72, C.I. I. Direct Orange 106, C.I. I. Direct Orange 107, C.I. I. Direct Red 2, C.I. I. Direct Red 39, C.I. I. Direct Red 83, C.I. I. Direct Red 89, C.I. I. Direct Red 240, C.I. I. Direct Red 242, C.I. I. Direct Red 247, C.I. I. Direct Violet 48, C.I. I. Direct Violet 51, C.I. I. Direct Violet 98, C.I. I. Direct Blue 15, C.I. I. Direct Blue 67, C.I. I. Direct Blue 71, C.I. I. Direct Blue 98, C.I. I. Direct Blue 168, C.I. I. Direct Blue 202, C.I. I. Direct Blue 236, C.I. I. Direct Blue 249, C.I. I. Direct Blue 270, C.I. I. Direct Green 59, C.I. I. Direct Green 85, C.I. I. Direct Brown 44, C.I. I. Direct Brown 106, C.I. I. Direct Brown 195, C.I. I. Direct Brown 210, C.I. I. Direct Brown 223, C.I. I. Direct Brown 224, C.I. I. Direct Black 1, C.I. I. Direct Black 17, C.I. I. Direct Black 19, C.I. I. Direct Black 54 and the like are further disclosed in JP-A-62-70802, JP-A-1-161202, JP-A-1-172906, JP-A-1-172907, JP-A-1-183602, JP-A-1-248105, The dichroic dyes described in JP-A-1-265205 and JP-A-7-261024 can also be preferably used. In order to produce dichroic molecules having various hues, two or more of these dichroic dyes may be blended. When a dichroic dye is used, the adsorption thickness may be 4 μm or more as described in JP-A No. 2002-082222.

If the content of the dichroic molecule in the film is too small, the degree of polarization is low, and if it is too large, the single-plate transmittance is lowered. Therefore, the polyvinyl alcohol polymer constituting the film matrix is usually used. On the other hand, it is adjusted to a range of 0.01% by mass to 5% by mass.
A preferable film thickness of the polarizer is preferably 5 μm to 40 μm, and more preferably 10 μm to 30 μm. The ratio between the thickness of the polarizer and the thickness of the protective film described later is 0.01 ≦ A (polarizer film thickness) / B (protective film thickness) ≦ 0.16 described in JP-A No. 2002-174727. A range is also preferable.
The crossing angle between the slow axis of the protective film and the absorption axis of the polarizer may be any value, but is preferably parallel or an azimuth angle of 45 ± 20 °.

(Polarizing plate manufacturing process)
Next, the manufacturing process of the polarizing plate of this invention is demonstrated.
The production process of the polarizing plate in the present invention is preferably composed of a swelling process, a dyeing process, a hardening process, a stretching process, a drying process, a protective film bonding process, and a post-bonding drying process. The order of the dyeing step, the hardening step, and the stretching step may be arbitrarily changed, or several steps may be combined and performed simultaneously. Further, as described in Japanese Patent No. 3331615, washing with water after the hardening step can be preferably performed.

  In the present invention, it is particularly preferable to sequentially perform the swelling process, the dyeing process, the hardening process, the stretching process, the drying process, the protective film bonding process, and the drying process after bonding in the order described. An on-line surface inspection step may be provided during or after the above-described steps.

The swelling process is preferably performed only with water, but as described in JP-A-10-153709, in order to stabilize optical performance and avoid wrinkling of the polarizing plate substrate in the production line, polarized light is used. It is also possible to manage the degree of swelling of the polarizing plate substrate by swelling the plate substrate with an aqueous boric acid solution.
Moreover, although the temperature and time of a swelling process can be defined arbitrarily, 10 to 60 degreeC and 5 to 2000 second are preferable.
For the dyeing step, the method described in JP-A-2002-86554 can be used. Further, as a dyeing method, not only immersion but any means such as application or spraying of iodine or a dye solution can be used. Further, as described in JP-A-2002-290025, iodine concentration, dye bath temperature, draw ratio in the bath, and a method of dyeing while stirring the bath liquid in the bath may be used.

When higher-order iodine ions are used as the dichroic molecule, in order to obtain a high-contrast polarizing plate, it is preferable to use a solution obtained by dissolving iodine in an aqueous potassium iodide solution in the dyeing step. In this case, iodine in the iodine-potassium iodide aqueous solution is preferably 0.05 to 20 g / l, potassium iodide is 3 to 200 g / l, and the mass ratio of iodine and potassium iodide is preferably 1 to 2000. The dyeing time is preferably 10 to 1200 seconds, and the liquid temperature is preferably 10 to 60 ° C. More preferably, the iodine is 0.5 to 2 g / l, the potassium iodide is 30 to 120 g / l, the mass ratio of iodine to potassium iodide is 30 to 120, the dyeing time is 30 to 600 seconds, and the liquid temperature is 20-50 degreeC is good.
Further, as described in Japanese Patent No. 3145747, boron compounds such as boric acid and borax may be added to the dyeing solution.

  In the hardening step, it is preferable to immerse in the crosslinking agent solution or apply the solution to contain the crosslinking agent. Further, as described in JP-A-11-52130, the hardening process can be performed in several steps.

  As the cross-linking agent, those described in US Reissue Patent No. 232897 can be used, and as described in Japanese Patent No. 3357109, a polyhydric aldehyde may be used as a cross-linking agent in order to improve dimensional stability. However, boric acids are most preferably used. When boric acid is used as a crosslinking agent used in the hardening step, metal ions may be added to the boric acid-potassium iodide aqueous solution. Zinc chloride is preferred as the metal ion, but as described in JP 2000-35512 A, zinc halides such as zinc iodide, zinc sulfates, zinc acetates and the like are used instead of zinc chloride. You can also.

  In the present invention, it is preferable to prepare a boric acid-potassium iodide aqueous solution to which zinc chloride has been added, and perform dura- tion by immersing the PVA film. Boric acid is preferably 1 to 100 g / l, potassium iodide is 1 to 120 g / l, zinc chloride is preferably 0.01 to 10 g / l, hardening time is preferably 10 to 1200 seconds, and liquid temperature is preferably 10 to 60 ° C. . More preferably, boric acid is 10 to 80 g / l, potassium iodide is 5 to 100 g / l, zinc chloride is 0.02 to 8 g / l, hardening time is 30 to 600 seconds, and liquid temperature is 20 to 50 ° C is preferable.

  For the stretching step, a longitudinal uniaxial stretching method as described in US Pat. No. 2,454,515, or a tenter method as described in JP-A-2002-86554 can be preferably used. A preferable draw ratio is 2 times or more and 12 times or less, and more preferably 3 times or more and 10 times or less. Moreover, the relationship between the draw ratio, the thickness of the original fabric and the thickness of the polarizer is described in JP-A No. 2002-040256 (polarizer film thickness / raw film thickness after bonding of the protective film) × (total draw ratio) > 0.17 or the relationship between the width of the polarizer when leaving the final bath and the width of the polarizer when bonding the protective film is 0.80 ≦ (protective film pasting) described in JP-A-2002-040247 It is also preferable to satisfy the following condition: polarizer width at the time / width of the polarizer when leaving the final bath) ≦ 0.95.

  As the drying step, a method known in JP-A-2002-86554 can be used, but a preferable temperature range is 30 ° C. to 100 ° C., and a preferable drying time is 30 seconds to 60 minutes. Further, as described in Japanese Patent No. 3148513, heat treatment is performed so that the fading temperature in water is 50 ° C. or higher, or as described in Japanese Patent Laid-Open Nos. 07-325215 and 07-325218. Aging in a temperature and humidity controlled atmosphere can also be preferably performed.

  A protective film bonding process is a process of bonding the both surfaces of the above-mentioned polarizer which went out of the drying process with two protective films. A method of bonding with a pair of rolls is preferably used so that the adhesive liquid is supplied immediately before bonding and the polarizer and the protective film are overlapped. In addition, as described in JP-A-2001-296426 and JP-A-2002-86554, the moisture content of the polarizer at the time of bonding is adjusted in order to suppress the groove-like unevenness of the record due to the stretching of the polarizer. It is preferable to do. In the present invention, a moisture content of 0.1% to 30% is preferably used.

  The adhesive between the polarizer and the protective film is not particularly limited, and examples thereof include PVA resin (including modified PVA such as acetoacetyl group, sulfonic acid group, carboxyl group, oxyalkylene group) and boron compound aqueous solution. PVA resin is preferable. The thickness of the adhesive layer is preferably 0.01 to 5 μm, and particularly preferably 0.05 to 3 μm after drying.

Moreover, in order to improve the adhesive force of a polarizer and a protective film, it is preferable to perform adhesion after surface-treating the protective film to make it hydrophilic. The surface treatment method is not particularly limited, and a known method such as a saponification method using an alkaline solution or a corona treatment method can be used. Further, an easy-adhesion layer such as a gelatin undercoat layer may be provided after the surface treatment. As described in JP-A-2002-267839, the contact angle of the protective film surface with water is preferably 50 ° or less.
The drying conditions after bonding are in accordance with the method described in JP-A-2002-86554, but the preferred temperature range is 30 ° C. to 100 ° C., and the preferred drying time is 30 seconds to 60 minutes. It is also preferable to perform aging in an atmosphere with temperature and humidity control as described in JP-A-07-325220.

The element content in the polarizer is as follows: iodine 0.1-3.0 g / m ² , boron 0.1-5.0 g / m ² , potassium 0.1-2.00 g / m ² , zinc 0-2. It is preferably 00 g / m ² . Further, the potassium content may be 0.2% by mass or less as described in JP-A No. 2001-166143, and the zinc content in the polarizer is described in JP-A No. 2000-035512. It is good also as 0.04 mass%-0.5 mass%.

  As described in Japanese Patent No. 3323255, in order to increase the dimensional stability of the polarizing plate, an organic titanium compound and / or an organic zirconium compound is added and used in any of the dyeing process, stretching process and hardening process And at least 1 type of compound chosen from the organic titanium compound and the organic zirconium compound can also be contained. A dichroic dye may be added to adjust the hue of the polarizing plate.

(Characteristics of polarizing plate)
(1) Transmittance and degree of polarization The preferred single plate transmittance of the polarizing plate of the present invention is 42.5% or more and 49.5% or less, more preferably 42.8% or more and 49.0% or less. A preferable range of the degree of polarization defined by Formula 4 is 99.900% or more and 99.999% or less, and more preferably 99.940% or more and 99.995% or less. A preferable range of the parallel transmittance is 36% or more and 42% or less, and a preferable range of the orthogonal transmittance is 0.001% or more and 0.05% or less. A preferable range of the dichroic ratio defined by Formula 5 is 48 or more and 1215 or less, and more preferably 53 or more and 525 or less.

ここで、Ｋ、Ｓ（λ）、ｙ（λ）、τ（λ）は以下の通りである。

The above-described transmittance is defined by the following formula based on JISZ8701.

Here, K, S (λ), y (λ), and τ (λ) are as follows.

S (λ): spectral distribution of standard light used for color display y (λ): color matching function in XYZ system τ (λ): spectral transmittance

The degree of polarization is defined by Equation 4 below.

The dichroic ratio is defined by the following formula 5.

The iodine concentration and the single plate transmittance may be within the ranges described in JP-A No. 2002-258051.
The parallel transmittance may be small in wavelength dependency as described in JP-A-2001-083328 and JP-A-2002-022950. The optical characteristics when the polarizing plates are arranged in crossed Nicols may be in the range described in Japanese Patent Laid-Open No. 2001-091136, and the relationship between parallel transmittance and orthogonal transmittance is disclosed in Japanese Patent Laid-Open No. 2002-174728. It may be within the range described.

  As described in Japanese Patent Application Laid-Open No. 2002-221618, the standard deviation of the parallel transmittance every 10 nm when the light wavelength is between 420 and 700 nm is 3 or less, and the light wavelength is between 420 and 700 nm. The minimum value of (parallel transmittance / orthogonal transmittance) every 10 nm may be 300 or more.

  The parallel transmittance and the orthogonal transmittance at a wavelength of 440 nm of the polarizing plate, the parallel transmittance, the parallel transmittance and the orthogonal transmittance at a wavelength of 550 nm, and the parallel transmittance and the orthogonal transmittance at a wavelength of 610 nm are disclosed in JP-A No. 2002-258042 and JP-A No. 2002-80442. The range described in 2002-258043 can also be preferably performed.

(2) Hue The hue of the polarizing plate of the present invention is preferably evaluated using the lightness index L * and chromaticness index a * and b * in the L * a * b * color system recommended as the CIE uniform perceptual space. Is done.
L *, a *, and b * are defined by Equation 6 using X, Y, and Z described above.

Here, X ₀ , Y ₀ , and Z ₀ represent tristimulus values of the illumination light source. In the case of standard light C, X ₀ = 98.072, Y ₀ = 100, Z ₀ = 118.225, and standard light D _In the case of ₆₅ , X ₀ = 95.045, Y ₀ = 100, Z ₀ = 108.892.

  The preferable range of a * for a single polarizing plate is −2.5 or more and 0.2 or less, and more preferably −2.0 or more and 0 or less. The preferred b * range of a single polarizing plate is 1.5 or more and 5 or less, and more preferably 2 or more and 4.5 or less. The preferable range of a * of the parallel transmitted light of the two polarizing plates is −4.0 to 0, and more preferably −3.5 to −0.5. The preferable range of b * of the parallel transmitted light of the two polarizing plates is 2.0 or more and 8 or less, and more preferably 2.5 or more and 7 or less. The preferable range of a * of the orthogonally transmitted light of the two polarizing plates is −0.5 or more and 1.0 or less, and more preferably 0 or more and 2 or less. The preferable range of b * of the orthogonally transmitted light of the two polarizing plates is −2.0 or more and 2 or less, and more preferably −1.5 or more and 0.5 or less.

The hue may be evaluated by the chromaticity coordinates (x, y) calculated from the aforementioned X, Y, and Z. For example, the chromaticity (x _p , y _p ) of the parallel transmitted light of the two polarizing plates. And the chromaticity (x _c , y _c ) of the orthogonal transmitted light are within the ranges described in JP-A-2002-214436, JP-A-2001-166136, and JP-A-2002-169024, or the relationship between the hue and the absorbance. It can also be preferably performed within the range described in JP-A-2001-311827.

(3) Viewing angle characteristics When a polarizing plate is arranged in crossed Nicol and light with a wavelength of 550 nm is incident, when vertical light is incident, from a azimuth of 45 degrees with respect to the polarization axis, 40 degrees with respect to the normal line It is also preferable that the transmittance ratio and the xy chromaticity difference when the light is incident at an angle of within the range described in Japanese Patent Application Laid-Open Nos. 2001-166135 and 2001-166137. Further, as described in JP-A-10-068817, the light transmittance (T ₀ ) in the vertical direction of the polarizing plate laminate having the crossed Nicols arrangement and the light transmission in the direction inclined by 60 ° from the normal line of the laminate. The ratio (T ₆₀ / T ₀ ) to the rate (T ₆₀ ) is 10000 or less, or as described in JP-A No. 2002-139625, the polarizing plate is at an arbitrary angle from the normal to an elevation angle of 80 degrees. When natural light is incident, the transmittance difference of transmitted light within a wavelength range of 20 nm within the wavelength range of 520 to 640 nm of the transmission spectrum is set to 6% or less, or a film described in JP-A-08-248201 It is also preferable that the brightness difference of the transmitted light at an arbitrary place 1 cm above is within 30%.

(4) Durability (4-1) Wet heat durability As described in JP-A-2001-116922, light transmittance and polarization degree before and after standing in an atmosphere of 60 ° C. and 90% RH for 500 hours. It is preferable that the change rate of is 3% or less based on the absolute value. In particular, the change rate of the light transmittance is 2% or less, and the change rate of the polarization degree is preferably 1.0% or less, more preferably 0.1% or less based on the absolute value. Further, as described in JP-A-07-0777608, it is also preferred that the degree of polarization after standing at 80 ° C. and 90% RH for 500 hours is 95% or more and the single transmittance is 38% or more.

(4-2) Dry durability It is preferable that the light transmittance and the rate of change of the degree of polarization before and after leaving in a dry atmosphere at 80 ° C. for 500 hours are also 3% or less based on absolute values. In particular, the change rate of the light transmittance is preferably 2% or less, and the change rate of the polarization degree is preferably 1.0% or less, more preferably 0.1% or less based on the absolute value.

(4-3) Other Durability Further, as described in JP-A-06-167611, the shrinkage rate after being left at 80 ° C. for 2 hours is 0.5% or less, or the both sides of the glass plate are crossed. The x and y values after leaving the Nicol-arranged polarizing plate laminate in an atmosphere of 69 ° C. for 750 hours are within the range described in JP-A-10-068818, or an atmosphere of 80 ° C. and 90% RH. the change in spectral intensity ratio of the 105 cm ^-1 and 157cm ^-1 after 200 hours standing processing by Raman spectroscopy at medium, it is also preferable to fall within the range as described in JP-a-08-094834 and JP-a-09-197127 It can be carried out.

(5) Orientation degree The higher the degree of orientation of PVA, the better the polarization performance, but the range of 0.2 to 1.0 is preferable as the order parameter value calculated by means such as polarization Raman scattering or polarization FT-IR. It is. Further, as described in JP-A-59-133509, the difference between the orientation coefficient of the polymer segment in the entire amorphous region of the polarizer and the orientation coefficient of the occupied molecule (0.75 or more) is at least 0. 15, the orientation coefficient of the amorphous region of the polarizer is 0.65 to 0.85 as described in JP-A No. 04-204907, and the higher order iodine ions of I ₃ ⁻ and I ₅ ⁻ It is also preferable to set the degree of orientation to 0.8 to 1.0 as an order parameter value.

(6) Other properties As described in JP-A-2002-006133, the contraction force in the absorption axis direction per unit width when heated at 80 ° C. for 30 minutes is 4.0 N / cm or less, As described in 2002-236213, when the polarizing plate was placed under heating conditions of 70 ° C. for 120 hours, both the dimensional change rate in the absorption axis direction and the dimensional change rate in the polarization axis direction of the polarizing plate were It is also preferable to make it within ± 0.6%, or to set the moisture content of the polarizing plate to 3% by mass or less as described in JP-A-2002-090546. Further, as described in JP-A No. 2000-249832, the surface roughness in the direction perpendicular to the stretching axis is set to 0.04 μm or less based on the center line average roughness, or described in JP-A No. 10-268294. The refractive index n ₀ in the transmission axis direction is preferably made larger than 1.6, or the relationship between the thickness of the polarizing plate and the thickness of the protective film is preferably within the range described in JP-A-10-111411. be able to.

(Functionalization of polarizing plate)
The polarizing plate of the present invention includes an LCD viewing angle widening film, a retardation film such as a λ / 4 plate for application to a reflective LCD, an antireflection film for improving display visibility, a brightness enhancement film, It is preferably used as a functionalized polarizing plate combined with an optical film having functional layers such as a coat layer, a forward scattering layer, and an antiglare (antiglare) layer.

A configuration example in which the polarizing plate of the present invention and the above-described functional optical film are combined is shown in FIG.
The functional optical film 3 may be bonded to the polarizer 2 through an adhesive layer as a protective film on one side of the polarizing plate 5 (FIG. 1A), and the protective films 1a and 1b are attached to both surfaces of the polarizer 2. The functional optical film 3 may be bonded to the provided polarizing plate 5 through the adhesive layer 4 (FIG. 1B). In the former case, an arbitrary transparent protective film may be used for the other protective film 1. Moreover, in the polarizing plate of this invention, it is also preferable to stick an optical functional layer to a protective film through an adhesion layer, and to set it as the structure of FIG. It is also preferable that the peel strength between the layers such as the functional layer and the protective film is 4.0 N / 25 mm or more described in JP-A No. 2002-311238. The functional optical film is preferably disposed on the liquid crystal module side according to the intended function, or on the side opposite to the liquid crystal module, that is, on the display side or the backlight side.

The functional optical film used in combination with the polarizing plate of the present invention will be described below.
(1) Viewing Angle Enlargement Film The polarizing plate of the present invention includes TN (Twisted Nematic), IPS (In-Plane Switching), OCB (Optically Compensated Bend), VA (Vertically Aligned), ECB (Electrically Bold). It can be used in combination with a viewing angle widening film proposed for the display mode.

As a viewing angle widening film for the TN mode, the Japan Printing Society Vol. 36, No. 3 (1999) p. 40-44, monthly display August issue (2002) p. No. 20-24, JP-A-4-229828, JP-A-6-75115, JP-A-6-214116, JP-A-8-50206, etc. are preferably used in combination. The
A preferred configuration of the viewing angle widening film for the TN mode has an alignment layer and an optically anisotropic layer in this order on the transparent polymer film. Although a viewing angle expansion film may be used by being bonded to a polarizing plate via an adhesive, SID'00 Dig. , P. As described in 551 (2000), it is particularly preferable from the viewpoint of thinning that one of the protective films of the polarizer is also used.

  The alignment layer can be provided by means such as a rubbing treatment of an organic compound (preferably a polymer), oblique deposition of an inorganic compound, or formation of a layer having a microgroup. Furthermore, an alignment layer in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known. The rubbing treatment is preferably performed by rubbing the surface of the polymer layer several times in a certain direction with paper or cloth. It is preferable that the absorption axis direction and the rubbing direction of the polarizer are substantially parallel. As the polymer used for the alignment layer, polyimide, polyvinyl alcohol, a polymer having a polymerizable group described in JP-A-9-152509, and the like can be preferably used. The thickness of the alignment layer is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm.

The optically anisotropic layer preferably contains a liquid crystalline compound. The liquid crystal compound used in the present invention particularly preferably has a discotic compound (discotic liquid crystal). The discotic liquid crystal molecule has a disk-like core portion like a triphenylene derivative, and has a structure in which side chains extend radially therefrom. In order to impart stability over time, it is also preferable to further introduce a group that reacts with heat, light or the like. Preferred examples of the discotic liquid crystal are described in JP-A-8-50206.
Examples of discotic liquid crystal molecules are shown below.

  The discotic liquid crystal molecules are aligned almost parallel to the film plane with a pretilt angle in the rubbing direction in the vicinity of the alignment layer, and the discotic liquid crystal molecules are oriented so that they are perpendicular to the plane on the opposite air side. doing. The discotic liquid crystal layer as a whole has a hybrid alignment, and this layer structure can realize a wide viewing angle of a TN mode TFT-LCD.

  The optically anisotropic layer is generally a discotic compound and another compound (for example, a polymerizable monomer, a photopolymerization initiator) dissolved in a solvent, coated on the alignment layer, dried, and then discotic nematic. After heating to the phase formation temperature, it is obtained by polymerization by irradiation with UV light or the like and further cooling. The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline compound used in the present invention is preferably 70 to 300 ° C, particularly preferably 70 to 170 ° C.

In addition to the discotic compound added to the optically anisotropic layer, the compound has compatibility with the discotic compound and can give a preferable change in tilt angle to the liquid crystalline discotic compound or inhibit the alignment. Any compound can be used as long as it is not. Among these, additives for controlling the orientation on the air interface side such as polymerizable monomers (eg, compounds having vinyl group, vinyloxy group, acryloyl group and methacryloyl group), fluorine-containing triazine compounds are cellulose acetate, cellulose acetate pro Mention may be made of polymers such as pionate, hydroxypropylcellulose and cellulose acetate butyrate. These compounds are generally used in an amount of 0.1 to 50% by mass, preferably 0.1 to 30% by mass, based on the discotic compound.
The thickness of the optically anisotropic layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm.

  A preferred embodiment of the viewing angle widening film is composed of a cellulose acylate film as a transparent substrate film, an alignment layer provided thereon, and an optically anisotropic layer comprising a discotic liquid crystal formed on the alignment layer And the optically anisotropic layer is crosslinked by UV light irradiation.

  In addition to the above, when the viewing angle widening film and the polarizing plate of the present invention are combined, for example, as described in JP-A-07-198942, a compound having an optical axis in a direction intersecting the plate surface is used. It is also preferable to laminate with a phase difference plate exhibiting anisotropy in refraction or to make the dimensional change rate of the protective film and the optically anisotropic layer substantially the same as described in JP-A No. 2002-258052. It can be carried out. Further, as described in JP-A-12-258632, the moisture content of the polarizing plate bonded to the viewing angle widening film is set to 2.4% or less, or as described in JP-A-2002-267839. Further, the contact angle with water on the surface of the viewing angle widening film can be preferably set to 70 ° or less.

  The viewing angle widening film for an IPS mode liquid crystal cell is used for optical compensation of liquid crystal molecules aligned in parallel to the substrate surface and for improving the viewing angle characteristics of the orthogonal transmittance of the polarizing plate during black display without an electric field. In the IPS mode, black is displayed when no electric field is applied, and the transmission axes of the pair of upper and lower polarizing plates are orthogonal. However, when observed from an oblique direction, the crossing angle of the transmission axes is not 90 °, and leakage light is generated, resulting in a decrease in contrast. When the polarizing plate of the present invention is used in an IPS mode liquid crystal cell, the in-plane retardation as described in JP-A-10-54982 is close to 0 and the thickness direction is reduced in order to reduce leakage light. It is preferably used in combination with a viewing angle widening film having a phase difference.

  The OCB mode viewing angle widening film for liquid crystal cells is intended to improve the viewing angle characteristics of black display by optically compensating the liquid crystal layer that is vertically aligned at the center of the liquid crystal layer by applying an electric field and tilted near the substrate interface. used. When the polarizing plate of the present invention is used in an OCB mode liquid crystal cell, it is preferably used in combination with a viewing angle widening film in which a discotic liquid crystalline compound as described in US Pat. No. 5,805,253 is hybrid-aligned.

  The viewing angle widening film for liquid crystal cells in the VA mode improves the viewing angle characteristics of black display in a state where liquid crystal molecules are vertically aligned with respect to the substrate surface in the absence of an electric field. As such a viewing angle widening film, a film having an in-plane retardation close to 0 and having a retardation in the thickness direction as described in Japanese Patent No. 2866372, and a discotic compound are used. Films arranged in parallel to the substrate, stretched films with the same in-plane retardation value laminated so that the slow axes are orthogonal, and liquid crystals to prevent the deterioration of orthogonal transmittance in the oblique direction of the polarizing plate It is preferably used in combination with a laminate of films made of rod-like compounds such as molecules.

(2) Retardation film The polarizing plate of the present invention preferably has a retardation layer. The retardation layer in the present invention is preferably a λ / 4 plate, and can be used as a circularly polarizing plate by laminating the polarizing plate of the present invention and the λ / 4 plate. The circularly polarizing plate has a function of converting incident light into circularly polarized light, and is preferably used for a reflective liquid crystal display device, a transflective liquid crystal display device such as an ECB mode, or an organic EL element.

  The λ / 4 plate used in the present invention is a retardation film having a retardation (Re) of approximately ¼ of the wavelength in the visible light wavelength range in order to obtain almost perfect circularly polarized light in the visible light wavelength range. It is preferable that “Retardation of approximately ¼ in the wavelength range of visible light” means that the longer the wavelength is from 400 to 700 nm, the larger the retardation, and the retardation value (Re450) measured at a wavelength of 450 nm is 80 to 125 nm. And the range which satisfies the relationship whose retardation value (Re590) measured by wavelength 590nm is 120-160 nm is shown. It is more preferable that Re590-Re450 ≧ 5 nm, and it is particularly preferable that Re590-Re450 ≧ 10 nm.

  The λ / 4 plate used in the present invention is not particularly limited as long as the above conditions are satisfied, but for example, described in JP-A-5-27118, JP-A-10-68816, and JP-A-10-90521. A λ / 4 plate obtained by laminating a plurality of polymer films, a λ / 4 plate obtained by stretching a single polymer film described in WO00 / 65384, WO00 / 26705, JP 2000-284126 A, A known λ / 4 plate such as a λ / 4 plate in which at least one optically anisotropic layer is provided on a polymer film described in JP-A-2002-31717 can be used. Moreover, the direction of the slow axis of the polymer film and the orientation direction of the optically anisotropic layer can be arranged in any direction according to the liquid crystal cell.

  In the circularly polarizing plate, the slow axis of the λ / 4 plate and the transmission axis of the polarizer can intersect at an arbitrary angle, but preferably intersect within a range of 45 ° ± 20 °. However, the slow axis of the λ / 4 plate and the transmission axis of the polarizer may intersect within a range other than the above.

  When the λ / 4 plate is formed by laminating the λ / 4 plate and the λ / 2 plate, as described in Japanese Patent No. 3236304 and Japanese Patent Laid-Open No. 10-68816, the λ / 4 plate and The λ / 2 plate is preferably bonded so that the angle formed between the slow axis in the plane of the λ / 2 plate and the transmission axis of the polarizing plate is substantially 75 ° and 15 °.

(3) Antireflection film The polarizing plate of the present invention can be used in combination with an antireflection film. For the anti-reflection film, either a film having a reflectance of about 1.5% only by applying a single layer of a low refractive index material such as a fluorine-based polymer, or a film having a reflectance of 1% or less using multilayer interference of a thin film is used. it can. In the present invention, a structure in which a low refractive index layer and at least one layer having a higher refractive index than that of the low refractive index layer (that is, a high refractive index layer and a middle refractive index layer) is laminated on a transparent support is preferably used. The In addition, Nitto Technical Report, vol. 38, no. 1, may, 2000, pages 26 to 28 and JP-A No. 2002-301783 can also be preferably used.
The refractive index of each layer satisfies the following relationship.

The refractive index of the high refractive index layer> The refractive index of the medium refractive index layer> The refractive index of the transparent support> The refractive index of the low refractive index layer. A transparent polymer film can be preferably used.

  The refractive index of the low refractive index layer is 1.20 to 1.55, preferably 1.30 to 1.50. The low refractive index layer is preferably used as an outermost layer having scratch resistance and antifouling properties. In order to improve the scratch resistance, it is also preferable to impart slipperiness to the surface using a material containing a silicone group or fluorine.

Examples of the fluorine-containing compound include paragraph numbers [0018] to [0026] of JP-A-9-222503, paragraph numbers [0019] to [0030] of JP-A-11-38202, and JP-A-2001-40284. The compounds described in paragraph Nos. [0027] to [0028] and JP-A No. 2000-284102 can be preferably used.
The silicone-containing compound is preferably a compound having a polysiloxane structure, but reactive silicone (eg, Silaplane (manufactured by Chisso Corporation), silanol group-containing polysiloxane at both ends (JP-A-11-258403), etc. An organometallic compound such as a silane coupling agent and a specific fluorine-containing hydrocarbon group-containing silane coupling agent may be cured by a condensation reaction in the presence of a catalyst (Japanese Patent Laid-Open No. 58-142958). Gazettes, 58-147483, 58-147484, JP-A-9-157582, 11-106704, JP-A-2000-117902, 2001-48590, 2002-2002. 53804).
The low refractive index layer has an average primary particle diameter of 1 to 150 nm such as fillers (for example, silicon dioxide (silica), fluorine-containing particles (magnesium fluoride, calcium fluoride, barium fluoride)) as additives other than the above. And a low refractive index inorganic compound, organic fine particles described in paragraphs [0020] to [0038] of JP-A No. 11-3820, silane coupling agents, slip agents, surfactants, and the like are also preferably included. be able to.

The low refractive index layer may be formed by a vapor phase method (vacuum vapor deposition method, sputtering method, ion plating method, plasma CVD method, etc.), but is preferably formed by a coating method because it can be manufactured at low cost. . As the coating method, dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, and micro gravure can be preferably used.
The film thickness of the low refractive index layer is preferably 30 to 200 nm, more preferably 50 to 150 nm, and most preferably 60 to 120 nm.

The medium refractive index layer and the high refractive index layer preferably have a constitution in which ultrafine particles of high refractive index having an average particle size of 100 nm or less are dispersed in a matrix material. The inorganic compound fine particles having a high refractive index include inorganic compounds having a refractive index of 1.65 or more, for example, oxides such as Ti, Zn, Sb, Sn, Zr, Ce, Ta, La, and In, and metal atoms thereof. A composite oxide or the like can be preferably used.
Such ultrafine particles may be obtained by treating the surface of the particles with a surface treatment agent (silane coupling agent, etc .: JP-A Nos. 11-295503, 11-153703, 2000-9908, anionic compounds or (Organic metal coupling agent: JP-A No. 2001-310432, etc.), core-shell structure with a high refractive index particle as a core (JP-A No. 2001-166104, etc.), or a specific dispersant (eg, JP-A No. 11- No. 153703, Patent No. US62010858B1, Japanese Patent Laid-Open No. 2002-27776069, etc.).

As the matrix material, conventionally known thermoplastic resins, curable resin films, and the like can be used, but JP-A-2000-47004, 2001-315242, 2001-31871, and 2001-296401. It is also possible to use a curable film obtained from a polyfunctional material described in a gazette or the like or a metal alkoxide composition described in JP-A-2001-293818 or the like.
The refractive index of the high refractive index layer is preferably 1.70 to 2.20. The thickness of the high refractive index layer is preferably 5 nm to 10 μm, and more preferably 10 nm to 1 μm.
The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.50 to 1.70.

  The haze of the antireflection film is preferably 5% or less, more preferably 3% or less. Further, the strength of the film is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test according to JIS K5400.

(4) Brightness improving film The polarizing plate of this invention can be used in combination with a brightness improving film. The brightness enhancement film has a function of separating circularly polarized light or linearly polarized light, and is disposed between the polarizing plate and the backlight, and reflects or scatters one circularly polarized light or linearly polarized light back to the backlight side. Re-reflected light from the backlight part partially changes the polarization state and partially transmits when re-entering the brightness enhancement film and the polarizing plate, so the light utilization rate is improved by repeating this process. The front luminance is improved to about 1.4 times. As the brightness enhancement film, an anisotropic reflection system and an anisotropic scattering system are known, and both can be combined with the polarizing plate of the present invention.

  In the anisotropic reflection system, a brightness enhancement film having anisotropy in reflectance and transmittance is known by laminating a uniaxially stretched film and an unstretched film in multiple layers and increasing the refractive index difference in the stretching direction. Multilayer film systems using the principle of dielectric mirrors (described in the specifications of WO95 / 17691, WO95 / 17692, WO95 / 17699) and cholesteric liquid crystal systems (European Patent No. 606940A2, Japanese Patent Laid-Open No. Hei 8- No. 271731) is known. DBEF-E, DBEF-D, and DBEF-M (all manufactured by 3M) are used as multi-layer brightness enhancement films using the principle of dielectric mirrors, and NIPOCS (Nitto Denko Corporation) as a cholesteric liquid crystal brightness enhancement film. )) Is preferably used in the present invention. For NIPOCS, see Nitto Giho, vol. 38, no. 1, may, 2000, pages 19 to 21 and the like.

Further, in the present invention, the positive values described in the specifications of WO97 / 32223, WO97 / 32224, WO97 / 32225, WO97 / 32226 and JP-A-9-274108 and 11-174231 are described. It is also preferable to use in combination with an anisotropic scattering type brightness enhancement film obtained by uniaxially stretching by blending an intrinsic birefringent polymer and a negative intrinsic birefringent polymer. As the anisotropic scattering system brightness enhancement film, DRPF-H (manufactured by 3M) is preferable.
The polarizing plate and the brightness enhancement film of the present invention are preferably used as an integrated type in which one of the polarizing film and the protective film of the polarizing plate is bonded via an adhesive.

(5) Other functional optical films The polarizing plate of the present invention further comprises a hard coat layer, a forward scattering layer, an antiglare (antiglare) layer, a gas barrier layer, a sliding layer, an antistatic layer, an undercoat layer, a protective layer, and the like. It is also preferable to use in combination with the provided functional optical film. These functional layers are also preferably used in combination with each other in the same layer as the antireflection layer in the above-mentioned antireflection film or the optically anisotropic layer in the viewing angle compensation film. These functional layers can be used by providing either one side or both sides of the polarizer side and the surface opposite to the polarizer (more air side surface).

(5-1) Hard coat layer The polarizing plate of the present invention is preferably combined with a functional optical film having a hard coat layer provided on the surface of the transparent support in order to impart mechanical strength such as scratch resistance. . When the hard coat layer is applied to the above-described antireflection film, it is particularly preferable to provide it between the transparent support and the high refractive index layer.
The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of the curable compound by light and / or heat. The curable functional group is preferably a photopolymerizable functional group, and the hydrous functional group-containing organometallic compound is preferably an organic alkoxysilyl compound. As specific constitutional compositions of the hard coat layer, for example, those described in JP-A Nos. 2002-144913, 2000-9908 and WO0 / 46617 can be preferably used.
The film thickness of the hard coat layer is preferably 0.2 to 100 μm.
The strength of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test according to JIS K5400. Further, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

  As the material for forming the hard coat layer, a compound containing an ethylenically unsaturated group or a compound containing a ring-opening polymerizable group can be used, and these compounds can be used alone or in combination. Preferred examples of the compound containing an ethylenically unsaturated group include ethylene glycol diacrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol. Polyacrylates of polyols such as hexaacrylate; epoxy acrylates such as diacrylate of bisphenol A diglycidyl ether, diacrylate of hexanediol diglycidyl ether; obtained by reaction of polyisocyanate and hydroxyl group-containing acrylate such as hydroxyethyl acrylate Examples of preferred compounds include urethane acrylates. Moreover, as a commercially available compound, EB-600, EB-40, EB-140, EB-1150, EB-1290K, IRR214, EB-2220, TMPTA, TMPTMA (above, Daicel UCB Co., Ltd. product), UV -6300, UV-1700B (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and the like.

  Preferred examples of the compound containing a ring-opening polymerizable group include ethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, trimethylol ethane triglycidyl ether, trimethylol propane triglycidyl ether, glycerol triglycidyl ether as glycidyl ethers. Triglycidyl trishydroxyethyl isocyanurate, sorbitol tetraglycidyl ether, pentaerythritol tetraglycyl ether, polyglycidyl ether of cresol novolac resin, polyglycidyl ether of phenol novolac resin, etc. Celoxide 2021P, Celoxide 2081, Epoxide GT-301, Epolide GT-401, EHPE3150CE (above, Oxetane, OXT-121, OXT-221, OX-SQ, PNOX-1009 (above, manufactured by Toagosei Co., Ltd.), etc. Can be mentioned. In addition, a polymer of glycidyl (meth) acrylate or a copolymer of a monomer that can be copolymerized with glycidyl (meth) acrylate may be used for the hard coat layer.

  In the hard coat layer, fine particles of oxide such as silicon, titanium, zirconium, and aluminum are used to reduce curing shrinkage of the hard coat layer, improve adhesion to the substrate, and reduce curling of the hard coat treated article of the present invention. It is also preferable to add crosslinked fine particles such as crosslinked fine particles such as polyethylene, polystyrene, poly (meth) acrylic acid esters, polydimethylsiloxane, etc., and fine organic particles such as fine crosslinked rubber particles such as SBR and NBR. These crosslinked fine particles preferably have an average particle size of 1 nm to 20000 nm. Further, the shape of the crosslinked fine particles can be used without any particular limitation, such as a spherical shape, a rod shape, a needle shape, or a plate shape. The addition amount of the fine particles is preferably 60% by volume or less, more preferably 40% by volume or less of the hard coat layer after curing.

  In the case of adding the inorganic fine particles described above, since the affinity with the binder polymer is generally poor, it contains a metal such as silicon, aluminum, titanium, etc., and an alkoxide group, carboxylic acid group, sulfonic acid group, phosphonic acid group, etc. It is also preferable to perform a surface treatment using a surface treatment agent having a functional group of

  The hard coat layer is preferably cured using heat or active energy rays. Among them, active energy rays such as radiation, gamma rays, alpha rays, electron rays, and ultraviolet rays are more preferred, and safety and productivity are improved. In view of the above, it is particularly preferable to use an electron beam or an ultraviolet ray. In the case of curing with heat, in consideration of the heat resistance of the plastic itself, the heating temperature is preferably 140 ° C. or lower, more preferably 100 ° C. or lower.

(5-2) Forward scattering layer The forward scattering layer is used to improve the viewing angle characteristics (hue and luminance distribution) in the vertical and horizontal directions when the polarizing plate of the present invention is applied to a liquid crystal display device. In the present invention, a configuration in which fine particles having different refractive indexes are dispersed in a binder is preferable. The construction of JP-A No. 199809, JP-A No. 2002-107512 that defines the haze value as 40% or more can be used. In addition, in order to control the viewing angle characteristics of haze, the polarizing plate of the present invention is also preferably used in combination with “Lumisty” described in Sumitomo Chemical's technical report “Photofunctional Films” on pages 31-39. be able to.

(5-3) Antiglare layer The antiglare (antiglare) layer is used to scatter reflected light and prevent reflection. The antiglare function is obtained by forming irregularities on the outermost surface (display side) of the liquid crystal display device. The haze of the optical film having an antiglare function is preferably 3 to 30%, more preferably 5 to 20%, and most preferably 7 to 20%.
The method for forming irregularities on the film surface is, for example, a method of adding fine particles to form irregularities on the film surface (for example, JP-A No. 2000-271878), relatively large particles (particle size 0.05 to 2 μm). ) Is added in a small amount (0.1 to 50% by mass) (for example, JP-A Nos. 2000-281410, 2000-95893, 2001-100004, and 2001). No. 281407, etc.), a method of physically transferring the concavo-convex shape onto the film surface (for example, as an embossing method, JP-A-63-278839, JP-A-11-183710, JP-A-2000-275401) Etc.) can be preferably used.

(Liquid crystal display device using polarizing plate)
Next, a liquid crystal display device in which the polarizing plate of the present invention is used will be described.
In a liquid crystal display device having a liquid crystal cell and two polarizing plates disposed on both sides thereof, at least one polarizing plate is the polarizing plate of the present invention.
FIG. 2 is an example of a liquid crystal display device in which the polarizing plate of the present invention is used.

The liquid crystal display device shown in FIG. 2 of the present invention includes a liquid crystal cell (10-13), and an upper polarizing plate 6 and a lower polarizing plate 17 that are disposed with the liquid crystal cell (10-13) interposed therebetween. The polarizing plate is sandwiched between a polarizer and a pair of transparent protective films, but is shown as an integrated polarizing plate in FIG. The liquid crystal cell includes a liquid crystal layer formed of an upper electrode substrate 10 and a lower electrode substrate 13 and liquid crystal molecules 12 sandwiched therebetween. The liquid crystal cell has different alignment states of liquid crystal molecules that perform ON / OFF display. However, the polarizing plate of the present invention can be used in any display mode regardless of the transmissive and reflective types.
Among these display modes, the OCB mode or the VA mode is preferable.

  An alignment film (not shown) is formed on the surface of the electrode substrates 10 and 13 in contact with the liquid crystal molecules 12 (hereinafter sometimes referred to as “inner surface”), and is formed by a rubbing process or the like applied on the alignment film. The orientation of the liquid crystal molecules 12 in a state where no electric field is applied or a state where a low voltage is applied is controlled. Further, on the inner surfaces of the substrates 10 and 13, a transparent electrode (not shown) capable of applying an electric field to the liquid crystal layer made of the liquid crystal molecules 12 is formed.

The rubbing direction of the TN mode is applied in directions perpendicular to each other on the upper and lower substrates, and the magnitude of the tilt angle can be controlled by the strength and the number of rubbing times. The alignment film is formed by applying and baking a polyimide film. The magnitude of the twist angle (twist angle) of the liquid crystal layer is determined by the crossing angle of the upper and lower substrates in the rubbing direction and the chiral agent added to the liquid crystal material. Here, a chiral agent having a pitch of about 60 μm is added so that the twist angle becomes 90 °.
The twist angle is in the vicinity of 90 ° (85 to 95 °) in the case of a notebook computer, a personal computer monitor, and a liquid crystal display device for a television, and is 0 to 70 ° in the case of use as a reflective display device such as a mobile phone. Set. In the IPS mode and the ECB mode, the twist angle is 0 °. In the IPS mode, electrodes are disposed only on the lower substrate 8 and an electric field parallel to the substrate surface is applied. In the OCB mode, there is no twist angle and the tilt angle is increased, and in the VA mode, the liquid crystal molecules 12 are aligned perpendicular to the upper and lower substrates.

Here, the magnitude of the product Δnd of the thickness d of the liquid crystal layer and the refractive index anisotropy Δn changes the brightness during white display. Therefore, in order to obtain the maximum brightness, the range is set for each display mode.
The crossing angle between the absorption axis 7 of the upper polarizing plate 6 and the absorption axis 18 of the lower polarizing plate 17 is generally laminated substantially orthogonally to obtain a high contrast. The crossing angle between the absorption axis 7 of the upper polarizing plate 6 of the liquid crystal cell and the rubbing direction of the upper substrate 10 varies depending on the liquid crystal display mode, but is generally set to be parallel or vertical in the TN and IPS modes. In OCB and ECB modes, it is often set to 45 °. However, the optimum value differs in each display mode for adjusting the color tone and viewing angle of the display color, and the present invention is not limited to this range.

  The liquid crystal display device in which the polarizing plate of the present invention is used is not limited to the configuration of FIG. 2, and may include other members. For example, a color filter may be disposed between the liquid crystal cell and the polarizer. Moreover, the viewing angle widening film mentioned above can also be separately arranged between the liquid crystal cell and the polarizing plate. The polarizing plates 6 and 17 and the optically anisotropic layers (viewing angle widening films) 8 and 15 may be arranged in a laminated form bonded with an adhesive, and one of the liquid crystal cell side protective films is used for widening the viewing angle. It may be arranged as a so-called integrated elliptical polarizing plate.

  When the liquid crystal display device using the polarizing plate of the present invention is used as a transmission type, a backlight using a cold cathode or a hot cathode fluorescent tube, or a light emitting diode, a field emission element, or an electroluminescent element as a light source. Can be placed on the back. Further, the liquid crystal display device in which the polarizing plate of the present invention is used may be of a reflective type. In such a case, only one polarizing plate may be disposed on the observation side, and the back of the liquid crystal cell or under the liquid crystal cell. A reflective film is installed on the inner surface of the side substrate. Of course, a front light using the light source may be provided on the liquid crystal cell observation side.

[Example 1]
(Preparation of cellulose acylate film 1)
<Preparation of cellulose acetate solution>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution A.

(Cellulose acylate solution A composition)
Cellulose acetate with acetylation degree 2.8 100.0 parts by mass Hydrophobizing agent: biphenyl phosphate 3.0 parts by mass Hydrophobizing agent: A-12 5.0 parts by mass Hydrophobizing agent: A-2 4.0 parts by mass Methylene chloride (first solvent) 402.0 parts by mass Methanol (second solvent) 60.0 parts by mass

<Preparation of matting agent solution>
The following composition was charged into a disperser and stirred to dissolve each component to prepare a matting agent solution.

(Matting agent solution composition)
Silica particles having an average particle diameter of 20 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd. 2.0 parts by mass Methylene chloride (first solvent) 75.0 parts by mass Methanol (second solvent) 12.7 parts by mass Cellulose acylate solution A 10.3 parts by mass

<Preparation of UV absorber solution>
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a UV absorber solution.

(UV absorber solution composition)
UV absorber (A) 4.0 parts by weight UV absorber (B) 8.0 parts by weight Methylene chloride (first solvent) 58.4 parts by weight Methanol (second solvent) 8.7 parts by weight Cellulose acylate solution A 12.8 parts by mass

ＵＶ吸収剤Ａ

UV absorber A

ＵＶ吸収剤Ｂ

UV absorber B

  94.6 parts by mass of the cellulose acylate solution A, 1.3 parts by mass of the matting agent solution, and 4.1 parts by mass of the UV absorber solution were mixed after filtration, and cast using a band casting machine. The film was peeled from the band with a residual solvent content of 35%, and the film was stretched transversely at a stretch ratio of 25% using a tenter under the condition of 140 ° C., and held at 140 ° C. for 30 seconds with the stretched width. Thereafter, the clip was removed and dried at 140 ° C. for 40 minutes to produce a cellulose acylate film. The resulting cellulose acylate film had a residual solvent amount of 0.2% and a film thickness of 91 μm.

  Cellulose acylate films 2 to 5 were produced in the same manner except that the type of cellulose acylate, the type of hydrophobizing agent, the amount added, the type of UV agent, the amount added, and the tenter stretch ratio were changed to the contents shown in Table 1.

(Measurement of optical properties)
Further, Re and Rth at 25 ° C. and 60% of a cellulose acylate film produced by the following method were measured.
In-plane retardation Re (0) was measured using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments). Retardation Re (40) and Re (-40) were measured with the in-plane slow axis as the tilt axis at 40 ° and -40 °. Using the film thickness and the refractive index nx in the slow axis direction as parameters, the refractive index ny and the thickness direction in the fast axis direction are fitted to these measured values Re (0), Re (40), Re (−40). The refractive index nz was determined by calculation to determine the Rth retardation value. The measurement wavelength was 590 nm.
The material of the cellulose acylate film and the characteristic values of the obtained film are shown in Table 1.

  In Table 1, hydrophobizing agents A-2, A-5, and A-12 are as described in the [Best Mode for Carrying Out the Invention] column.

[Example 2]
(Saponification treatment)
Cellulose acylate films 1 to 5 were immersed in a saponification solution having the composition shown in Table 2 at 55 ° C. for 2 minutes. It wash | cleaned in the room temperature water-washing tub, and neutralized using 0.1 N sulfuric acid at 30 degreeC. Again, it was washed in a water bath at room temperature and further dried with hot air at 100 ° C. In this way, polarizing plate protective films 1-i to ni, 2-i, ni, 3-i, ni, 4-i, ni, 5-i and ni were produced.
Table 2 shows the composition of the saponification solution.

(Measurement of abundance ratio of hydrophobizing agent and acylation degree of cellulose acylate)
The saponified protective film was cut obliquely at an angle of 1 ° with respect to the film surface, and the resulting film cross section was subjected to mapping measurement with a time-of-flight secondary ion mass spectrometer (TOF-SIMS). In the positive measurement, for each molecular weight of 1,000 or less low molecular weight compound of a portion corresponding to the outside than the depth 0.1 [mu], of the region than the average value and the 2μ of the peak intensity of the molecular + H ⁺ ions corresponding to the inner molecular + H ⁺ ions Ro / Ri was determined by taking a ratio with the average value of the peak intensities.
Moreover _CH 3 COO of a portion corresponding to the outside than the depth 0.1μ in negative measurement ^- and _C 2 _H 7 COO ^- _CH 3 in a region corresponding more to the inside mean and 2μ of the sum of the peak intensities of COO ^- and C Ao / Ai was determined by taking the ratio of the average value of the sum of the peak intensities of ₂ H ₇ COO ⁻ .
The results are shown in Table 3.

[Example 3]
A polarizer was prepared by adsorbing iodine to the stretched polyvinyl alcohol film, and the cellulose acylate film 1 prepared in Example 1 was attached to one side of the polarizer using a polyvinyl alcohol-based adhesive. The transmission axis of the polarizer and the slow axis of the cellulose acylate film were arranged in parallel.
Further, the polarizing plate protective film 1-i saponified in Example 2 was attached to the opposite side of the polarizer using a polyvinyl alcohol-based adhesive. Thus, a polarizing plate (1-i) was produced.

  Polarizing plate protective film 1-ro-ni, 2-i, 2-i, 3-i, ni, 4-i, ni, 5-i, ni is similarly applied to polarizing plate 1-ro-ni, 2-i, D, 3-I, D, 4-I, D, 5-I, D were prepared.

  Thus, about the produced polarizing plate, the number of the point defect per 1 m x 1 m and a spot-like nonuniformity was measured. Further, the polarizing plate was punched into 20 cm × 20 cm, allowed to age at 60 ° C. and 95% for 500 hours, and the degree of peeling between the polarizer and the protective film was visually evaluated. The results are shown in Table 3. From the results in Table 3, it can be seen that the saponification method and the polarizing plate protective film of the present invention are preferable with few defects.

[Example 4]
(Formation of alignment film)
On the saponified cellulose acylate 2-ni, a coating solution having the following composition was applied at 24 ml / m ² with a # 14 wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds.
Next, the formed film was rubbed in the direction of 45 ° with the stretching direction of cellulose acylate 2-ni (transparent support) (substantially coincident with the slow axis).

(Orientation film coating solution composition)
Modified polyvinyl alcohol 20 parts by mass Water 360 parts by mass Methanol 120 parts by mass Glutaraldehyde (crosslinking agent) 1.0 part by mass

変性ポリビニルアルコール

Modified polyvinyl alcohol

(Formation of optically anisotropic layer)
On the alignment film, 91 parts by mass of the following discotic compound, 9 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.), cellulose acetate butyrate (CAB531-1, Eastman Chemical) 15 parts by mass), 3 parts by mass of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy), and 1 part by mass of a sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) A coating solution dissolved in a portion of methyl ethyl ketone was applied with 5.2 ml / m ² with a # 3 wire bar coater. This was affixed to a metal frame and heated in a thermostatic bath at 130 ° C. for 2 minutes to orient the discotic compound. Next, using a 120 W / cm high-pressure mercury lamp at 90 ° C., UV irradiation was performed for 1 minute to polymerize the discotic compound. Then, it stood to cool to room temperature. In this way, an optically anisotropic layer was formed, and an optical compensation sheet 2-ni was obtained.

ディスコティック化合物

Discotic compound

(Preparation of polarizing plate)
A polarizer was prepared by adsorbing iodine to a stretched polyvinyl alcohol film.
Next, the transparent support side of the produced optical compensation sheet 2-ni was attached to the side of the polarizer using a polyvinyl alcohol-based adhesive. The slow axis of the transparent support and the transmission axis of the polarizer were arranged in parallel.
A commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) was saponified in the same manner as in Example 2 using the saponification solution 4, and the other side of the polarizer (with a polyvinyl alcohol adhesive) The optical compensation sheet was affixed to the side not affixed.
Thus, the elliptically polarizing plate (2-ni) of this invention was produced. Further, an elliptically polarizing plate (2-i) of a comparative example was produced in the same manner except that the saponified cellulose acylate film was changed to 2-i.

[Example 5]
(Preparation of bend alignment liquid crystal cell)
A polyimide film was provided as an alignment film on a glass substrate with an ITO electrode, and the alignment film was rubbed. The obtained two glass substrates were faced to each other so that the rubbing directions were parallel to each other, and the cell gap was set to 5.7 μm. A bend-aligned liquid crystal cell was prepared by injecting a liquid crystal compound (ZLI1132, manufactured by Merck & Co., Inc.) having a Δn of 0.1396 into the cell gap.

(Production of liquid crystal display device)
Two elliptical polarizing plates (2-ni) of the present invention were attached so as to sandwich the prepared bend alignment cell. The optically anisotropic layer of the polarizing plate faced the cell substrate, and the rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer facing it were antiparallel. A liquid crystal display device was prepared in the same manner for the elliptically polarizing plate (2-a) of the comparative example. As a result, it was found that the liquid crystal display device using the elliptically polarizing plate of the present invention is preferable to the liquid crystal display device using the elliptically polarizing plate of the comparative example with less surface failure.

[Example 6]
[Production and evaluation of VA liquid crystal display]
1% by mass of octadecyldimethylammonium chloride (coupling agent) was added to a 3% by mass aqueous polyvinyl alcohol solution. This was spin-coated on a glass substrate with an ITO electrode, heat-treated at 160 ° C., and then rubbed to form a vertical alignment film. The rubbing treatment was performed in opposite directions on the two glass substrates. Two glass substrates were opposed to each other so that the cell gap (d) was 5 μm. A liquid crystal compound (Δn: 0.08) mainly composed of ester and ethane was injected into the cell gap to prepare a vertically aligned liquid crystal cell. The product of Δn and d was 400 nm.

The produced polarizing plate 1-ni was preliminarily conditioned at 25 ° C. and 60% temperature and humidity, and then packaged in a moisture-proof bag and left for 3 days. The bag was a packaging material having a laminated structure of polyethylene terephthalate / aluminum / polyethylene, and the water vapor transmission rate was 1 × 10 ⁻⁵ g / m ² · Day or less.
Under an environment of 25 ° C. and 60%, the polarizing plate 1-ni was taken out and pasted to both surfaces of the created vertical alignment liquid crystal cell using an adhesive sheet to produce a liquid crystal display device.
It has been found that the liquid crystal display device using the polarizing plate of the present invention is preferable since it has no defects or spot-like failures.

FIG. 1 is an example of a configuration in which the polarizing plate of the present invention and a functional optical film are combined. FIG. 2 is an example of a liquid crystal display device in which the polarizing plate of the present invention is used.

Explanation of symbols

1, 1a, 1b Protective film 2 Polarizer 3 Functional optical film 4 Adhesive layer 5 Polarizing plate 6 Upper polarizing plate 7 Upper polarizing plate absorption axis 8 Upper optical anisotropic layer 9 Upper optical anisotropic layer orientation control direction 10 Liquid crystal Cell upper electrode substrate 11 Upper substrate alignment control direction 12 Liquid crystal molecule 13 Liquid crystal cell lower electrode substrate 14 Lower substrate alignment control direction 15 Lower optical anisotropic layer 16 Lower optical anisotropic layer alignment control direction 17 Lower polarizing plate 18 Lower polarizing plate Absorption axis

Claims (9)

  A method for producing a polarizing plate protective film, comprising immersing a thermoplastic resin film in a highly alkaline aqueous solution containing an antioxidant and performing a saponification treatment.   The manufacturing method of the polarizing plate protective film of Claim 1 in which this highly alkaline aqueous solution contains surfactant.   The method for producing a polarizing plate protective film according to claim 1 or 2, wherein the thermoplastic resin film is a cellulose acylate film containing 0.1 to 30% by mass of a low molecular weight compound having a molecular weight of 1,000 or less.   The cellulose acylate film contains 1 to 30% by mass of a compound having a molecular weight of 1,000 or less that decomposes in an aqueous alkali solution to produce a decomposed product soluble in the aqueous alkali solution. The manufacturing method of the polarizing plate protective film of description.   The cellulose acylate film contains at least one dissociable group having a pKa of 8 or more and 14 or less, and contains 1 to 30% by mass of a low molecular compound having a molecular weight of 1,000 or less. The manufacturing method of the polarizing plate protective film of description.   The polarizing plate protective film manufactured by the method of any one of Claims 1-5. The polarizing plate protective film according to claim 6, wherein the substitution degree of cellulose acylate and the low molecular weight compound satisfy the following relationship.
0 <Ao / Ai <1
0 ≦ Ro / Ri ≦ 0.9
Ao: degree of acylation of cellulose acylate in a region having a depth of 0.1 μm or less from the surface Ai: degree of acylation of cellulose acylate in a region having a depth of 2 μm or more from the surface Ro: depth from the surface Abundance of low molecular compounds in a region having a thickness of 0.1 μm or less Ri: abundance of low molecular compounds in a region having a depth of 2 μm or more from the surface   A polarizing plate having a protective film bonded to both sides of a polarizer, wherein at least one of the protective films is the polarizing plate protective film according to claim 6 or 7.   A liquid crystal display device having a liquid crystal cell and two polarizing plates arranged on both sides thereof, wherein at least one of the polarizing plates is the polarizing plate according to claim 8.

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