JP2014065763A - Cellulose acylate film, and polarizing plate and liquid crystal display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cellulose acylate film that improves durability of a polarizer, has a low haze, minimizes generation of display irregularity, can significantly reduce coloring by heat in a long period of time, and can reduce process contamination during manufacturing, and to provide a polarizing plate and a liquid crystal display device using the cellulose acylate film.SOLUTION: The cellulose acylate film comprises a compound expressed by formula (I) and cellulose acylate, and the polarizing plate and the liquid crystal display device include the cellulose acylate film. In the formula, Rrepresents an alkyl group having 1 to 12 carbon atoms; Rand Rrepresent a hydrogen atom, an alkyl group or an aryl group having 1 to 6 carbon atoms; Rrepresents an unsubstituted alkyl group having 1 to 6 carbon atoms; Arrepresents an aromatic group; m is an integer of 0 to 3; n is an integer of 1 to 4, and when n is 1, Arrepresents an unsubstituted aromatic group.

Description

  The present invention relates to a cellulose acylate film, a polarizing plate using the same, and a liquid crystal display device.

  The cellulose acylate film is used in various liquid crystal display devices as an optical member of a liquid crystal display device, for example, a support for an optical compensation film, a protective film for a polarizing plate, and the like.

In addition to being used indoors, such as for TV applications, the liquid crystal display device has been increasingly used outdoors, for example, mainly for portable devices. Therefore, development of a liquid crystal display device that can withstand use at higher temperatures and higher humidity than before has been demanded.
In addition, liquid crystal display devices are increasingly required to endure even under severe usage conditions in various applications, and a higher level of durability than ever has been required year by year.

  On the other hand, in order to suppress yellowing (increased yellowness index) that occurs when a cellulose acylate film is produced by melt film formation, a specific phenol derivative is incorporated into the cellulose acylate film as an antioxidant or deterioration inhibitor. Has been proposed (see Patent Document 1).

JP 2006-241428 A

In view of the above circumstances, the present invention has been made to develop a liquid crystal display device that can withstand severe use conditions such as high temperature and high humidity, and a cellulose acylate film used therefor.
When the liquid crystal display device is used under high temperature and high humidity, there arises a problem that unevenness due to the contraction of the polarizer occurs or the display performance deteriorates due to a change in optical characteristics. In addition, the prevention of yellowing in melt film formation and the improvement in durability when using a liquid crystal display device under high temperature and high humidity are different phenomena, including the working factors, and the knowledge at the time of melt film formation remains unchanged. It cannot be applied. There is no conventional knowledge that can improve the durability of polarizers at the stage where they are incorporated and used in liquid crystal display devices (especially at high temperatures and high humidity or during light irradiation), and new solutions must be developed. there were.
According to the study by the present inventors, according to the conventional knowledge, there is a technically high wall between the improvement of durability and the reduction of coloring of the cellulose acylate film such as yellowing.

  Accordingly, the present invention has been made to solve the above-mentioned problems with technically high walls under such circumstances, and improves the durability of the polarizer, lowers the haze, and causes display unevenness. A cellulose acylate film that can reduce coloration over a long period of time due to heat and can reduce process contamination during production, and a highly durable polarizing plate and liquid crystal display device using the same The task is to do.

The present inventors have studied from various viewpoints including radical stability and reactivity of various phenolic compounds. As a result, the cellulose acylate film has a bulky tertiary alkyl group at the ortho position of the phenolic hydroxyl group. It has been found that the inclusion of hindered phenols having a substituent is insufficient to solve the above problems. As a result of examining the cause, it was found that it is important to adjust the radical stability and reactivity while leaving the reactivity of the phenolic hydroxyl group rather than the radical stability when the phenolic hydroxyl group becomes a radical.
On the other hand, a compound having a phenolic hydroxyl group that easily reacts may be decomposed by an oxidation reaction or the like to cause coloring or the like when it is applied with energy such as heat or light, which is a big problem in practice.
The inventors of the present invention completed the present invention as a result of further investigation based on the above findings in order to achieve both improvement in light resistance and suppression of coloring when improving the durability of the polarizer. It came.

That is, the said subject was achieved by the following means.
(1) A cellulose acylate film containing at least one compound represented by the following general formula (I) and cellulose acylate.

[In General Formula (I), R ¹ represents an unsubstituted linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, and R ² and R ³ each independently represent a hydrogen atom, 1 to 6 carbon atoms. R ⁴ represents an unsubstituted alkyl group having 1 to 6 carbon atoms, and Ar ¹ represents a substituted or unsubstituted aromatic group. m represents an integer of 0 to 3, and n represents an integer of 1 to 4. However, when n is 1, Ar ¹ represents an unsubstituted aromatic group. ]
(2) The cellulose acylate film according to (1), wherein the compound represented by the general formula (I) is a compound represented by the following general formula (IA).

[In the general formula ^{(IA), R 1, R} 2, R 4, Ar 1, m and n are, in ^{R 1, R 2, R 4} , Ar 1, m and n as defined in the general formula (I) is there. ]
(3) The cellulose acylate film according to (2), wherein the compound represented by the general formula (IA) is a compound represented by the following general formula (IB).

[In the general formula (IB), ^{R 1} and Ar ¹ have the same meanings as ^{R 1} and Ar ¹ in the general formula (I). R ^2a and R ^2b each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Ar ^1a has the same meaning as Ar ¹ . ]
(4) The cellulose acylate film according to (3), wherein the compound represented by the general formula (IB) is a compound represented by the following general formula (IC).

[In the general formula (IC), ^{R 1} and Ar ¹ have the same meanings as ^{R 1} and Ar ¹ in the general formula (I). Ar ^1a has the same meaning as Ar ¹ . ]
(5) The cellulose acylate film according to any one of claims 1 to 4, wherein R ¹ is an unsubstituted linear, branched or cyclic alkyl group having 1 to 8 carbon atoms.
(6) The cellulose acylate film according to any one of (1) to (5), wherein R ¹ is a methyl group or a tert-butyl group.
(7) The cellulose acylate film according to any one of (1) to (6), wherein the acyl substitution degree (A) of the cellulose acylate satisfies the following formula.

          1.5 ≦ A ≦ 3.0

(8) The cellulose acylate film according to any one of (1) to (7), wherein the acetyl substitution degree (B) of the cellulose acylate satisfies the following formula.

          2.0 ≦ B ≦ 3.0

(9) The cellulose acylate film according to any one of (1) to (8), which further contains at least one polycondensation ester compound as a plasticizer.
(10) The polycondensed ester compound is obtained by polycondensing at least one dicarboxylic acid represented by the following general formula (a) and at least one diol represented by the following general formula (b) ( The cellulose acylate film as described in 9).

Formula (a)
_{HOC (= O) -X-CO} 2 H
General formula (b)
HO-Z-OH

[In General Formulas (a) and (b), X represents a divalent aliphatic group having 2 to 18 carbon atoms or a divalent aromatic group having 6 to 18 carbon atoms, and Z represents a divalent carbon number of 2 Represents an aliphatic group of ~ 8. ]
(11) The cellulose acylate film according to (9) or (10), wherein the polycondensed ester compound has a number average molecular weight of 500 to 2,000.
(12) The cellulose acylate film according to any one of (9) to (11), wherein a terminal of the polycondensed ester compound is sealed.
(13) The cellulose acylate film according to any one of (1) to (12), further comprising at least one kind of a carbohydrate compound composed of a monosaccharide or 2 to 10 monosaccharide units as a plasticizer. .
(14) The cellulose acylate film according to (13), wherein the carbohydrate compound has an alkyl group, an aryl group, or an acyl group.
(15) The cellulose acylate film according to (13) or (14), wherein the carbohydrate compound has an acyl group.
(16) A polarizing plate having at least the cellulose acylate film according to any one of (1) to (15) and a polarizer.
(17) A liquid crystal display device having at least the polarizing plate according to (16) and a liquid crystal cell.

  According to the present invention, a cellulose acylate film that improves the durability of a polarizer, has low haze, little display unevenness, can greatly reduce coloring due to heat over time, and can reduce process contamination during production. In addition, a polarizing plate and a liquid crystal display device using the same can be provided.

It is the disassembled perspective view which showed the internal structure of the liquid crystal display device typically. It is the schematic which shows an example when the cellulose acylate film of a three-layer structure is poured by simultaneous co-casting using a co-casting die.

Hereinafter, the present invention will be described in detail with reference to embodiments.
In addition, the numerical value range represented using "to" in this specification means the range which includes the numerical value described before and behind as a lower limit and an upper limit.
In the present specification, “group” described as each group is a substituted or unsubstituted group. For example, “alkyl group” means an alkyl group which may have a substituent. An “aliphatic group” is a linear, branched or cyclic aliphatic group that may be saturated or unsaturated (does not become an aromatic ring), or may have a substituent. Good.

<< Cellulose Acylate Film >>
The cellulose acylate film of the present invention contains a compound represented by the following general formula (I) and cellulose acylate.
The cellulose acylate film can exhibit the effect of suppressing the deterioration of the polarizing plate and is suitable for use as a protective film.

Hereinafter, the material contained in the cellulose acylate film of the present invention will be described in detail.
<1 Compound Represented by General Formula (I)>
The cellulose acylate film of the present invention contains a compound represented by the following general formula (I).

In the general formula (I), R ¹ represents an unsubstituted linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, and R ² and R ³ each independently represent a hydrogen atom or a carbon number of 1 to 6 An alkyl group or an aryl group is represented, R ⁴ represents an unsubstituted alkyl group having 1 to 6 carbon atoms, and Ar ¹ represents a substituted or unsubstituted aromatic group. m represents an integer of 0 to 3, and n represents an integer of 1 to 4. However, when n is 1, Ar ¹ represents an unsubstituted aromatic group.

Among the unsubstituted linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms in R ¹ , the unsubstituted linear and branched alkyl groups preferably have 1 to 10 carbon atoms, more preferably 1 to 10 carbon atoms. 8, more preferably 4-8. The number of carbon atoms of the cyclic alkyl group, that is, the cycloalkyl group is preferably 3 to 12, more preferably 5 to 12, and still more preferably 5 to 10. Here, the cycloalkyl ring of the cycloalkyl group is preferably a 3- to 7-membered ring, more preferably a 3- to 6-membered ring, further preferably a 5- or 6-membered ring, and particularly preferably a 6-membered ring. The cycloalkyl ring may have an alkyl group.

The unsubstituted linear, branched or cyclic alkyl group having 1 to 12 carbon atoms for R ¹ is, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n -Pentyl, tert-amyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, tert-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, cyclopropyl, cyclopentyl, cyclohexyl, Adamantyl.
Of these, R ¹ is preferably a methyl group or a tert-butyl group.

Carbon number of the alkyl group in R ² and R ³ is preferably 1 to 4, more preferably 1 or 2. The alkyl group may be linear, branched or cyclic, but is preferably linear. Examples of the alkyl group for R ² and R ³ include methyl, ethyl, n-hexyl, isohexyl, cyclopropyl, cyclopentyl, and cyclohexyl.
The number of carbon atoms of the aryl group in R ² and R ³ is preferably 6 to 12, more preferably 6 to 10, and still more preferably 6 to 8. Examples of the aryl group for R ² and R ³ include phenyl, tolyl, 2,4-dimethylphenyl, and naphthyl.
The alkyl group and aryl group in R ² and R ³ may have a substituent.

  Here, the substituent is not particularly limited, and is preferably an alkyl group (preferably having 1 to 10 carbon atoms such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl. , 1-carboxymethyl, etc.), alkenyl groups (preferably having 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl groups (preferably having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl, etc. Etc.), a cycloalkyl group (preferably having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), an aryl group (preferably having 6 to 26 carbon atoms such as phenyl, 1- Naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.) Heterocyclic group (preferably a heterocyclic group having 0 to 20 carbon atoms, wherein the ring-constituting hetero atom is preferably an oxygen atom, nitrogen atom or sulfur atom, preferably a 5- or 6-membered ring, and further a benzene ring or heterocyclic ring The ring may be condensed, and the ring may be a saturated ring, an unsaturated ring or an aromatic ring. For example, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2- Oxazolyl etc.), alkoxy group (preferably having 1 to 20 carbon atoms, for example, methoxy, ethoxy, isopropyloxy, benzyloxy etc.), aryloxy group (preferably having 6 to 26 carbon atoms, for example, phenoxy, 1-naphthyl) Oxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.),

  An alkylthio group (preferably having 1 to 20 carbon atoms, such as methylthio, ethylthio, isopropylthio, benzylthio, etc.), an arylthio group (preferably having 6 to 26 carbon atoms, such as phenylthio, 1-naphthylthio, 3-methylphenylthio, etc. , 4-methoxyphenylthio, etc.), acyl groups (including alkylcarbonyl groups, alkenylcarbonyl groups, arylcarbonyl groups, and heterocyclic carbonyl groups, preferably having 20 or less carbon atoms, such as acetyl, pivaloyl, acryloyl, metachloroyl, benzoyl , Nicotinoyl, etc.), alkoxycarbonyl groups (preferably having 2 to 20 carbon atoms, such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl, etc.), aryloxycarbonyl groups (preferably having 7 to 20 carbon atoms, such as phenyl Cicarbonyl, naphthyloxycarbonyl, etc.), amino group (including amino group, alkylamino group, arylamino group, heterocyclic amino group, preferably having 0 to 20 carbon atoms, such as amino, N, N-dimethylamino, N, N-diethylamino, N-ethylamino, anilino, 1-pyrrolidinyl, piperidino, morpholinyl, etc.), sulfonamide group (preferably having 0 to 20 carbon atoms, for example, N, N-dimethylsulfonamide, N-phenylsulfone) Amide, etc.), sulfamoyl groups (preferably having 0 to 20 carbon atoms, such as N, N-dimethylsulfamoyl, N-phenylsulfamoyl etc.), acyloxy groups (preferably having 1 to 20 carbon atoms, for example, Acetyloxy, benzoyloxy, etc.), carbamoyl groups (preferably having 1 to 20 carbon atoms, eg N, N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), acylamino group (preferably having 1 to 20 carbon atoms, such as acetylamino, acryloylamino, benzoylamino, nicotinamide, etc.), cyano group, hydroxyl group, mercapto group Or a halogen atom (For example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.) is mentioned.

Here, the substituent when R ² and R ³ are aryl groups is preferably an alkyl group or an alkoxy group, and more preferably an alkyl group.

R ² and R ³ are preferably a hydrogen atom, an unsubstituted alkyl group having 1 to 6 carbon atoms, or an unsubstituted aryl group, more preferably a hydrogen atom, an unsubstituted alkyl group having 1 to 6 carbon atoms. is there.

The alkyl group in R ⁴ may be linear, branched or cyclic, but is preferably a linear or branched alkyl group, and more preferably a linear alkyl group.
The number of carbon atoms of the alkyl group in R ⁴ is preferably 1 to 4, more preferably 1.
The alkyl group for R ⁴ is, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, cyclopropyl, cyclopentyl, And cyclohexyl.

The aromatic group in Ar ¹ may have a substituent, and examples of such a substituent include the aforementioned substituents. Among these substituents, an alkyl group and an alkoxy group are preferable, and an alkyl group is more preferable. In the present invention, an unsubstituted aromatic group is more preferable.
The number of carbon atoms of the aromatic group in Ar ¹ is preferably 6 to 12, more preferably 6 to 10, and still more preferably 6 to 8. Examples of Ar ¹ include phenyl, tolyl, 2,4-dimethylphenyl, and naphthyl.
In the present invention, at least one, preferably two, of —C (R ² ) (R ³ ) (Ar ¹ ) are preferably those in the ortho position of the phenolic hydroxyl group.

When m is 2 or more, the plurality of R4s may be the same or different, and when n is 2 or more, the plurality of —C (R ² ) (R ³ ) (Ar ¹ ) may be the same or different. Good.

m is preferably 0 or 1, more preferably 0.
n is preferably 1 or 2, and 2 is particularly preferable. In addition, when n is 1, m is preferably 0 to 2, more preferably 1 or 2, and particularly preferably 1.
When n is 1, Ar ¹ represents an unsubstituted aromatic group.

  The compound represented by the general formula (I) of the present invention is preferably a compound represented by the following general formula (IA), more preferably a compound represented by the following general formula (IB), and the following general formula (IC) Is more preferable.

In the general formula ^{(IA), R 1, R} 2, R 4, Ar 1, m and n are in the above ^{R 1, R 2, R 4} , Ar 1, m and n as defined in formula (I) .

In the general formula (IB), ^{R 1} and Ar ¹ have the same meanings as ^{R 1} and Ar ¹ in the general formula (I). R ^2a and R ^2b each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Ar ^1a has the same meaning as Ar ¹ .

In the general formula (IC), ^{R 1} and Ar ¹ have the same meanings as ^{R 1} and Ar ¹ in the general formula (I). Ar ^1a has the same meaning as Ar ¹ .

The molecular weight of the compound represented by the general formula (I) is preferably 200 to 1200, more preferably 250 to 800, and particularly preferably 300 to 600.
A molecular weight of 200 or more is preferable because volatilization from the film can be suppressed. It is preferable from a viewpoint of suppressing haze by setting it as 1200 or less.

  Specific examples of the compound represented by formula (I) are shown below, but the present invention is not limited to these.

  In general, the compound represented by the general formula (I) can be easily synthesized, for example, by subjecting a phenol derivative to an olefin compound (for example, styrene) under an acid catalyst.

The content of the compound represented by the general formula (I) in the cellulose acylate is not particularly limited, but is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the cellulose acylate. More preferably, it is -15 mass parts, and it is especially preferable that it is 0.3-10 mass parts.
It is preferable for the amount added to be 0.1 parts by mass or more because the moisture permeability can be effectively reduced. 20 parts by mass or less is preferable from the viewpoint of haze suppression.

<2 Cellulose acylate>
In the present invention, cellulose acylate is used as the main component of the film. Here, in the present specification, the “main component” refers to a component having a highest mass fraction in an embodiment in which there is one component as a raw material and in an embodiment having two or more components. One type of cellulose acylate may be used, or two or more types may be used. The acyl substituent of the cellulose acylate may be, for example, a cellulose acylate composed of an acetyl group alone, or a cellulose acylate having a plurality of different acyl substituents, or a mixture of different cellulose acylates. May be.

  Cellulose acylate raw material cellulose used in the present invention includes cotton linter and wood pulp (hardwood pulp, conifer pulp), and any cellulose acylate obtained from any raw material cellulose can be used and mixed in some cases. May be used. Detailed descriptions of these raw material celluloses can be found in, for example, Marusawa and Uda, “Plastic Materials Course (17) Fibrous Resin”, Nikkan Kogyo Shimbun (published in 1970), and Japan Institute of Invention and Publications. The cellulose described in 2001-1745 (pages 7-8) can be used.

  In the present invention, the acyl group of cellulose acylate may be only one type, or two or more types of acyl groups may be used. The cellulose acylate used in the present invention preferably has an acyl group having 2 to 4 carbon atoms as a substituent. When two or more kinds of acyl groups are used, one of them is preferably an acetyl group, and the acyl group having 2 to 4 carbon atoms is preferably propionyl or butyryl. These cellulose acylates can produce a solution having a preferable solubility, and in particular, a non-chlorine organic solvent can be used to produce a good solution. Further, a solution having a low viscosity and good filterability can be produced.

First, the cellulose acylate preferably used in the present invention will be described in detail.
Glucose units having β-1,4 bonds constituting cellulose have free hydroxyl groups at the 2nd, 3rd and 6th positions. Cellulose acylate is a polymer obtained by acylating part or all of these hydroxyl groups with an acyl group.
The degree of acyl substitution indicates the degree of acylation of the hydroxyl groups of cellulose located at the 2nd, 3rd and 6th positions, and the 2nd, 3rd and 6th hydroxyl groups of all glucose units are all acylated. In this case, the total acyl substitution degree is 3. For example, when all the glucose units are all acylated in all glucose units, the total acyl substitution degree is 1. Similarly, the total acyl substitution degree is 1 when all the hydroxyl groups of all glucoses are acylated at either the 6-position or 2-position in each glucose unit.
That is, the degree of acylation is shown by 3 when all hydroxyl groups in the glucose molecule are all acylated.

  The total acyl substitution degree (A) of the cellulose acylate used in the present invention is preferably 1.5 or more and 3 or less (1.5 ≦ A ≦ 3.0), and is 2.0 to 2.97. Is more preferably 2.5 or more and less than 2.97, and particularly preferably 2.70 to 2.95.

  The total acetyl substitution degree (B) of the cellulose acylate used in the present invention is preferably 2.0 or more and 3 or less (2.0 ≦ B ≦ 3.0), and is 2.0 to 2.97. Is more preferably 2.5 or more and less than 2.97, and particularly preferably 2.70 to 2.95.

  Moreover, in the cellulose acetate using only an acetyl group as the acyl group of cellulose acylate, the total degree of acetyl substitution (B) is 2.0 or more and 3 or less (2.0 ≦ B ≦ 3.0). Preferably, it is 2.0 to 2.97, more preferably 2.5 or more and less than 2.97, and particularly preferably 2.70 to 2.95.

  The acyl group having 2 or more carbon atoms of the cellulose acylate used in the present invention may be an aliphatic acyl group or an aromatic acyl group, and is not particularly limited. These are, for example, cellulose alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, aromatic alkylcarbonyl esters, and the like, each of which may further have a substituted group. Preferred examples of these include acetyl, propionyl, butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, isobutanoyl, tert-butanoyl, cyclohexanecarbonyl, oleoyl, benzoyl , Naphthylcarbonyl, cinnamoyl and the like. Among these, acetyl, propionyl, butanoyl, dodecanoyl, octadecanoyl, ter-butanoyl, oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl and the like are more preferable, and acetyl, propionyl, butanoyl (acyl group has 2 carbon atoms) is more preferable. And acetyl (when the cellulose acylate is cellulose acetate).

  In the acylation of cellulose, when an acid anhydride or acid chloride is used as an acylating agent, an organic acid such as acetic acid or methylene chloride is used as an organic solvent as a reaction solvent.

As the catalyst, when the acylating agent is an acid anhydride, a protic catalyst such as sulfuric acid is preferably used, and when the acylating agent is an acid chloride (for example, CH ₃ CH ₂ COCl), Basic compounds are used.

  The most common industrial synthesis method for mixed fatty acid esters of cellulose is to use cellulose mixed fatty acids containing fatty acids (acetic acid, propionic acid, valeric acid, etc.) corresponding to acetyl groups and other acyl groups or anhydrides thereof. This is a method of acylating with components.

  Cellulose acylate can be synthesized, for example, by the method described in JP-A-10-45804.

  From the viewpoint of moisture permeability, the film of the present invention preferably contains 5 to 99% by mass of cellulose acylate in the total solid content, more preferably 20 to 99% by mass, and particularly preferably 50 to 95% by mass. preferable.

<3 Other additives>
In the cellulose acylate film of the present invention, as a retardation adjusting agent (retardation developing agent and retardation reducing agent), as a plasticizer, a polycondensed ester compound (polymer), a polyhydric ester of a polyhydric alcohol, phthalic acid Esters, phosphate esters, and the like, and additives such as UV absorbers, antioxidants, matting agents, and the like can also be added.
In the present specification, the compound group may be described by incorporating a “system”, for example, as in the case of a phosphate ester compound. Means the same.

(Retardation reducing agent)
In the present invention, as the retardation reducing agent, a compound other than a phosphate ester compound or a known non-phosphate ester compound as an additive for a cellulose acylate film can be widely used.

  The polymer retardation reducing agent is selected from phosphoric acid polyester polymers, styrene polymers, acrylic polymers, and copolymers thereof, and acrylic polymers and styrene polymers are preferred. Moreover, it is preferable that at least one polymer having negative intrinsic birefringence, such as a styrene polymer and an acrylic polymer, is included.

  Examples of the low molecular weight retardation reducing agent which is a compound other than the non-phosphate ester compound include the following. These may be solid or oily. That is, the melting point and boiling point are not particularly limited. For example, mixing of an ultraviolet absorbing material at 20 ° C. or lower and 20 ° C. or higher, and a mixture of deterioration preventing agents are also possible. Furthermore, infrared absorbing dyes are described, for example, in JP-A No. 2001-194522. Moreover, the addition time may be added at any time in the cellulose acylate solution (dope) preparation step, but may be added by adding a step of adding an additive to the final preparation step of the dope preparation step. Furthermore, the amount of each material added is not particularly limited as long as the function is manifested.

  The low molecular weight retardation reducing agent which is a compound other than the non-phosphate ester compound is not particularly limited, but details are described in JP-A-2007-272177, [0066] to [0085].

  The compound represented by the general formula (1) described in [0066] to [0085] of JP-A-2007-272177 is obtained by a condensation reaction between a sulfonyl chloride derivative and an amine derivative as described in the publication. be able to.

  The compound represented by the general formula (2) described in JP-A-2007-272177 is a dehydration-condensation reaction between a carboxylic acid and an amine using a condensing agent (for example, dicyclohexylcarbodiimide (DCC)). It can be obtained by a substitution reaction between an acid chloride derivative and an amine derivative.

  The retardation reducing agent is more preferably an Rth reducing agent from the viewpoint of realizing a suitable Nz factor. Among the retardation reducing agents, examples of the Rth reducing agent include acrylic polymers and styrene polymers, and low molecular compounds represented by general formulas (3) to (7) described in JP-A-2007-272177. Among them, acrylic polymers and styrene polymers are preferable, and acrylic polymers are more preferable.

  The retardation reducing agent is preferably added at a rate of 0.01 to 30% by mass, more preferably 0.1 to 20% by mass, more preferably 0.1 to 10%, based on the cellulose resin. It is particularly preferable to add at a ratio of mass%. By making the addition amount 30% by mass or less, compatibility with the cellulose resin can be improved, and whitening can be suppressed. When using two or more types of retardation reducing agents, the total amount is preferably within the above range.

(Retardation expression agent)
The cellulose acylate film of the present invention preferably contains at least one retardation developer in order to develop a retardation value.
The retardation developer is not particularly limited, and examples thereof include those composed of rod-like or discotic compounds, and compounds exhibiting retardation development among the non-phosphate ester compounds. As the rod-like or discotic compound, a compound having at least two aromatic rings can be preferably used as a retardation developer.
The addition amount of the retardation enhancer composed of the rod-shaped compound is preferably 0.1 to 30 parts by mass, and preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component containing cellulose acylate. Further preferred. The discotic compound contained in the retardation developer is preferably less than 3 parts by mass, more preferably less than 2 parts by mass, and less than 1 part by mass with respect to 100 parts by mass of cellulose acylate. Is particularly preferred.
Since the discotic compound is superior to the rod-shaped compound in Rth retardation expression, it is preferably used when a particularly large Rth retardation is required. Two or more retardation developers may be used in combination.
The retardation developer preferably has a maximum absorption in the wavelength region of 250 to 400 nm, and preferably has substantially no absorption in the visible region.

  Details of the retardation enhancer are described on page 49 of published technical bulletin 2001-1745.

(Plasticizer (hydrophobizing agent))
The cellulose acylate film of the present invention has, as a plasticizer (hydrophobizing agent), a polyhydric alcohol polyhydric ester compound (hereinafter referred to as polyhydric alcohol ester plasticizer), a polycondensed ester compound (hereinafter polycondensed). It is preferable to include at least one compound selected from among ester plasticizers) and carbohydrate compounds (hereinafter referred to as carbohydrate derivative plasticizers).
As a plasticizer, what can reduce a moisture content, without reducing the glass transition temperature (Tg) of a cellulose acylate film as much as possible is preferable. By using such a plasticizer, it is possible to suppress the additive in the cellulose acylate film from diffusing into the polarizer layer under high temperature and high humidity, thereby improving the deterioration of the polarizer performance.
The plasticizer used in the present invention will be described in detail below.

(Polyhydric ester plasticizer)
The polyhydric alcohol that is a raw material for synthesizing the polyhydric alcohol ester plasticizer used in the present invention is represented by the following general formula (c).

General formula (c)
Rα- (OH) mα

  In general formula (c), Rα represents an mα-valent organic group, and mα represents a positive integer of 2 or more.

As preferable polyhydric alcohol contained in the said general formula (c), the following compounds are mentioned, for example. However, the present invention is not limited to these.
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, galactitol, mannitol, 3-methylpentane- Examples include 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.

  Among the polyhydric alcohol ester plasticizers, polyhydric alcohol esters using a polyhydric alcohol having 5 or more carbon atoms are preferable. Most preferably, it is C5-C20.

  There is no restriction | limiting in particular as monocarboxylic acid used for the synthesis | combination of a polyhydric alcohol ester, 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 the monocarboxylic acid include the following compounds, but the present invention is not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms is preferred. As for carbon number, 1-20 are more preferable, and 1-10 are especially preferable. When acetic acid is contained, the compatibility with the cellulose derivative is increased, and it is also preferable to use a mixture of acetic acid and another monocarboxylic acid.

  Preferred examples of the aliphatic monocarboxylic acid 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, tridecyl Acids, 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, and laccelic acid, undecylenic acid And unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.

  Preferred examples of the alicyclic monocarboxylic acid include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, and derivatives thereof.

  Preferred examples of the aromatic monocarboxylic acid 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 benzene rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid, and tetralincarboxylic acid. Although the aromatic monocarboxylic acid which has the above, or those derivatives can be mentioned, benzoic acid is especially preferable.

  The molecular weight of the polyhydric alcohol ester plasticizer is not particularly limited, but is preferably 300 to 3000, and more preferably 350 to 1500. A higher molecular weight is preferable because it is less likely to volatilize, and a lower molecular weight is preferable in terms of moisture permeability and compatibility with cellulose derivatives.

  The carboxylic acid used for the synthesis of the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the hydroxyl groups in the polyhydric alcohol may be esterified, or a part of the hydroxyl groups may be left as they are.

  The specific compound of a polyhydric alcohol ester is shown below.

(Polycondensed ester plasticizer)
The cellulose acylate film of the present invention preferably further contains a polycondensation ester plasticizer. By including a polycondensation ester plasticizer, an effect that a cellulose ester film excellent in humidity stability and polarizing plate durability can be obtained is obtained.
The polycondensation ester plasticizer is preferably obtained by polycondensation of at least one dicarboxylic acid represented by the following general formula (a) and at least one diol represented by the following general formula (b). .

Formula (a)
_{HOC (= O) -X-CO} 2 H
General formula (b)
HO-Z-OH

  In general formulas (a) and (b), X represents a divalent aliphatic group having 2 to 18 carbon atoms or a divalent aromatic group having 6 to 18 carbon atoms, and Z represents a divalent carbon number of 2 to 2. Represents an aliphatic group of 8; Here, the divalent aliphatic group having 2 to 8 carbon atoms may be linear or branched.

  Here, the divalent aliphatic group having 2 to 18 carbon atoms in X may be saturated or unsaturated, and may be a divalent chain or cyclic aliphatic group (for example, a cycloalkylene group). Any of these may be used. Moreover, when it is a bivalent chain aliphatic group, it may be linear or branched. 2-12 are more preferable and, as for carbon number of a bivalent aliphatic group, 2-6 are more preferable. Among them, the divalent aliphatic group having 2 to 18 carbon atoms is preferably a divalent chain saturated aliphatic group, more preferably a chain alkylene group, and a linear alkylene group. More preferably, it is a group. Examples of the chain aliphatic group having 2 to 18 carbon atoms include ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, decamethylene, dodecylene, propylene, 2-methyltrimethylene, 2, Examples include 2-dimethyltrimethylene, cyclopentylene, cyclohexylene and the like.

  The divalent aromatic group having 6 to 18 carbon atoms in X may be a divalent aromatic hydrocarbon group or a divalent aromatic heterocyclic group. As a bivalent aromatic group, 6-15 are preferable and, as for carbon number, 6-12 are more preferable. Examples of the aromatic ring in the divalent aromatic hydrocarbon group include a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring, and a terphenyl ring. The aromatic heterocyclic ring in the divalent aromatic heterocyclic group preferably contains at least one of an oxygen atom, a nitrogen atom or a sulfur atom as a ring constituent atom. Aromatic heterocycles are, for example, furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, Examples include heterocycles such as phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, and tetrazaindene. Among these, the aromatic ring in the divalent aromatic hydrocarbon group is preferably a benzene ring, naphthalene ring or biphenyl ring, and the aromatic heterocycle in the divalent aromatic heterocyclic group is a pyridine ring, triazine ring or quinoline. A ring is preferred.

Z represents a divalent aliphatic group having 2 to 8 carbon atoms. The divalent aliphatic group having 2 to 8 carbon atoms may be saturated or unsaturated, and may be any divalent chain or cyclic aliphatic group (for example, a cycloalkylene group). Also good. Further, when it is a divalent chain aliphatic group, it may be a divalent straight chain or a branched chain. As for carbon number of a bivalent aliphatic group, 2-6 are more preferable, and 2-4 are more preferable. Among them, the divalent aliphatic group having 2 to 8 carbon atoms is preferably a divalent chain saturated aliphatic group, more preferably a chain alkylene group, and even more preferably a linear alkylene group. Examples of the chain alkylene group having 5 to 10 carbon atoms include, for example, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, decamethylene, propylene, 2-methyltrimethylene, 2,2- Examples include dimethyltrimethylene.
Examples of the divalent cycloalkylene group include cyclopentylene and cyclohexylene.

  The polycondensed ester plasticizer may be obtained from at least one dicarboxylic acid having an aromatic ring (also referred to as aromatic dicarboxylic acid) and at least one aliphatic diol having an average carbon number of 2.5 to 8.0. preferable. Moreover, it is also preferable to obtain from the mixture of aromatic dicarboxylic acid and at least 1 type of aliphatic dicarboxylic acid, and at least 1 type of aliphatic diol whose average carbon number is 2.5-8.0.

Calculation of the average carbon number of the dicarboxylic acid residue is performed separately for the dicarboxylic acid residue and the diol residue.
The value calculated by multiplying the constituent carbon number by the composition ratio (molar fraction) of the dicarboxylic acid residue is defined as the average carbon number. For example, when the adipic acid residue and the phthalic acid residue are composed of 50 mol% each, the average carbon number is 7.0.
The same applies to the diol residue, and the average carbon number of the diol residue is a value calculated by multiplying the constituent carbon number by the composition ratio (molar fraction) of the diol residue. For example, when it is composed of 50 mol% of ethylene glycol residues and 50 mol% of 1,2-propanediol residues, the average carbon number is 2.5.

The number average molecular weight of the polycondensed ester plasticizer is preferably 500 to 2000, more preferably 600 to 1500, and still more preferably 700 to 1200. If the number average molecular weight of the polycondensed ester is 600 or more, the volatility is low, and film failure or process contamination due to volatilization under high temperature conditions during stretching of the cellulose ester film is less likely to occur.
Moreover, if it is 2000 or less, compatibility with a cellulose ester will become high, and it will become difficult to produce the bleed-out at the time of film forming and at the time of heat drawing.
The number average molecular weight of the polycondensed ester can be measured and evaluated by gel permeation chromatography. Further, in the case of a polyester polyol having an unsealed terminal, it can also be calculated from the amount of hydroxyl groups per mass (hereinafter also referred to as hydroxyl value). In the present invention, the hydroxyl value is determined by measuring the amount (mg) of potassium hydroxide required for neutralizing excess acetic acid after acetylating the polyester polyol.

When a mixture of an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid is used as the dicarboxylic acid component, the dicarboxylic acid component is preferably a dicarboxylic acid having an average carbon number of 5.5 to 10.0, more preferably 5 .6-8.
If the average carbon number is 5.5 or more, a polarizing plate having excellent durability can be obtained. If the average carbon number is 10 or less, the compatibility with the cellulose ester is excellent, and the occurrence of bleed-out can be suppressed in the process of forming the cellulose ester film.

The polycondensation ester obtained from the diol compound represented by the general formula (b) and the dicarboxylic acid containing an aromatic dicarboxylic acid contains an aromatic dicarboxylic acid residue.
In the present specification, a residue is a partial structure of a polycondensed ester and represents a partial structure having the characteristics of a monomer forming the polycondensed ester. For example, the dicarboxylic acid residue formed by dicarboxylic acid HOC (═O) —X—CO ₂ H is —C (═O) —X—C (═O) —. The aromatic dicarboxylic acid residue ratio of the polycondensed ester used in the present invention is preferably 40 mol% or more, and more preferably 40 mol% to 95 mol%.
By setting the aromatic dicarboxylic acid residue ratio to 40 mol% or more, a cellulose ester film exhibiting sufficient optical anisotropy can be obtained, and a polarizing plate excellent in durability can be obtained. Moreover, if it is 95 mol% or less, it is excellent in compatibility with a cellulose ester, and it can make it hard to produce a bleed-out also at the time of film forming of a cellulose ester film, and the time of heat-stretching.

Examples of the aromatic dicarboxylic acid that can be used for the synthesis of the polycondensed ester plasticizer include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 1,8. -Naphthalenedicarboxylic acid, 2,8-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, etc. can be mentioned. Of these, phthalic acid, terephthalic acid, and 2,6-naphthalenedicarboxylic acid are preferable, phthalic acid and terephthalic acid are more preferable, and terephthalic acid is more preferable.
In the polycondensed ester, an aromatic dicarboxylic acid residue derived from the aromatic dicarboxylic acid used for mixing is formed.

That is, the aromatic dicarboxylic acid residue preferably contains at least one of phthalic acid residue, terephthalic acid residue, and isophthalic acid residue, more preferably at least one of phthalic acid residue and terephthalic acid residue. A seed, more preferably a terephthalic acid residue.
By using terephthalic acid as the aromatic dicarboxylic acid for the synthesis of the polycondensed ester, the cellulose ester film is more compatible with the cellulose ester and less likely to bleed out during the formation of the cellulose ester film and during heat stretching. It can be. Moreover, aromatic dicarboxylic acid may be used alone or in combination of two or more. When two types are used, it is preferable to use phthalic acid and terephthalic acid.
By using together two kinds of aromatic dicarboxylic acids of phthalic acid and terephthalic acid, the polycondensation ester at normal temperature can be softened, which is preferable in terms of easy handling.
The content of the terephthalic acid residue in the dicarboxylic acid residue of the polycondensed ester is preferably 40 mol% to 100 mol%.
By setting the terephthalic acid residue ratio to 40 mol% or more, a cellulose ester film exhibiting sufficient optical anisotropy can be obtained.

The polycondensation ester obtained from the diol compound represented by the general formula (b) and the dicarboxylic acid containing an aliphatic dicarboxylic acid contains an aliphatic dicarboxylic acid residue.
Examples of the aliphatic dicarboxylic acid for synthesizing the polycondensed ester plasticizer include oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, Examples include dodecanedicarboxylic acid or 1,4-cyclohexanedicarboxylic acid.
In the polycondensed ester, an aliphatic dicarboxylic acid residue derived from the aliphatic dicarboxylic acid used in the synthesis is formed.

The aliphatic dicarboxylic acid residue preferably has an average carbon number of 5.5 to 10.0, more preferably 5.5 to 8.0, and preferably 5.5 to 7.0. Further preferred. If the average carbon number of the aliphatic dicarboxylic acid residue is 10.0 or less, the heat loss of the compound can be reduced, and the occurrence of surface failure that may be caused by process contamination due to bleed-out during drying of the cellulose acylate web is prevented. be able to. Moreover, it is preferable that the aliphatic dicarboxylic acid residue has an average carbon number of 5.5 or more because it is excellent in compatibility and precipitation of the polycondensed ester hardly occurs.
Specifically, the aliphatic dicarboxylic acid residue preferably includes a succinic acid residue, and when two types are used, it preferably includes a succinic acid residue and an adipic acid residue.
That is, in the synthesis of the polycondensed ester, one kind of aliphatic dicarboxylic acid may be used or two or more kinds may be used. When two kinds are used, it is preferable to use succinic acid and adipic acid. When one kind of aliphatic dicarboxylic acid is used for the synthesis of the polycondensed ester, it is preferable to use succinic acid. The average carbon number of the aliphatic dicarboxylic acid residue can be adjusted to a desired value, which is preferable in terms of compatibility with the cellulose ester.

  In the present invention, it is preferable to use two or three dicarboxylic acids for mixing in the formation of the polycondensed ester. When using two kinds, it is preferable to use one kind of aliphatic dicarboxylic acid and one kind of aromatic dicarboxylic acid. When using three kinds, one kind of aliphatic dicarboxylic acid and two kinds of aromatic dicarboxylic acid or aliphatic dicarboxylic acid are used. Two kinds of acids and one kind of aromatic dicarboxylic acid can be used. This is because the average carbon number value of the dicarboxylic acid residue can be easily adjusted, the content of the aromatic dicarboxylic acid residue can be within a preferable range, and the durability of the polarizer can be improved.

The polycondensation ester obtained from the diol compound represented by the general formula (b) and the dicarboxylic acid containing a dicarboxylic acid contains a diol residue.
In the present specification, the diol residue formed by the diol compound (HO—Z—OH) represented by the general formula (b) is —O—Z—O—.
Examples of the diol for synthesizing the polycondensed ester include an aromatic diol and an aliphatic diol. In the present invention, the diol is preferably synthesized using at least an aliphatic diol.
The polycondensed ester preferably contains an aliphatic diol residue having an average carbon number of 2.5 to 7.0, more preferably an aliphatic diol residue having an average carbon number of 2.5 to 4.0. .
When the average carbon number of the aliphatic diol residue is less than 7.0, the compatibility with the cellulose ester is improved, bleed-out is less likely to occur, and the heat loss of the compound is less likely to increase, and the cellulose acylate web is dried. It is difficult for a sheet-like failure that may be caused by process contamination at the time to occur. Further, the synthesis is easy if the average carbon number of the aliphatic diol residue is 2.5 or more.

  The aliphatic diol used for synthesizing the polycondensed ester plasticizer is preferably an alkyl diol or an alicyclic diol, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2 -Butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neo Pentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane) ), 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-penta Diol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, diethylene glycol, cyclohexanedimethanol Etc. are preferred. These are preferably used together with ethylene glycol as one or a mixture of two or more.

The aliphatic diol is more preferably at least one of ethylene glycol, 1,2-propanediol, and 1,3-propanediol, and particularly preferably at least one of ethylene glycol and 1,2-propanediol. One type. When synthesizing a polycondensation ester using two types of aliphatic diols, it is preferable to use ethylene glycol and 1,2-propanediol. By using 1,2-propanediol or 1,3-propanediol, crystallization of the polycondensed ester can be prevented.
In the polycondensed ester, a diol residue which is a diol component is incorporated into the polyester by a diol compound used for mixing.

That is, the polycondensation ester preferably contains at least one of an ethylene glycol residue, 1,2-propanediol residue and 1,3-propanediol residue as a diol residue, It is more preferably a 2-propanediol residue.
The aliphatic diol residue contained in the polycondensed ester preferably contains 10 mol% to 100 mol%, more preferably 20 mol% to 100 mol% of ethylene glycol residue.

The terminal of the polycondensed ester may be left as diol or carboxylic acid without being sealed (that is, the polymer chain length terminal is —OH or CO ₂ H), and further reacted with monocarboxylic acid or monoalcohol. So-called end sealing may be performed. In addition, by sealing the terminal of the polycondensed ester, the state at normal temperature is difficult to be in a solid form, the handling becomes good, and the cellulose ester film excellent in humidity stability and polarizing plate durability can be obtained. An effect is obtained.

As monocarboxylic acids used for sealing, acetic acid, propionic acid, butanoic acid, benzoic acid and the like are preferable. As monoalcohols used for sealing, methanol, ethanol, propanol, isopropanol, butanol, isobutanol and the like are preferable, and methanol is most preferable. When the number of carbon atoms of the monocarboxylic acid used at the terminal of the polycondensed ester is 7 or less, the loss on heating of the compound does not increase, and no surface failure occurs.
More preferably, the end of the polycondensed ester remains as a diol residue without being sealed, or is sealed with acetic acid, propionic acid or benzoic acid. It does not matter whether both ends of the polycondensed ester have the same sealing performance.
When both ends of the condensate are unsealed, the polycondensed ester is preferably a polyester polyol.

One aspect of the polycondensation ester is a polycondensation ester in which the aliphatic diol residue has 2.5 to 8.0 carbon atoms and both ends of the polycondensation ester are unblocked. When both ends of the polycondensed ester are sealed, it is preferably sealed by reacting with a monocarboxylic acid. At this time, both ends of the polycondensed ester are monocarboxylic acid residues.
In the present specification, the monocarboxylic acid residue formed from the monocarboxylic acid Rβ-COOH is Rβ-CO—. When both ends of the polycondensed ester are sealed with a monocarboxylic acid, the monocarboxylic acid is preferably an aliphatic monocarboxylic acid residue, and the monocarboxylic acid residue is an aliphatic monocarboxylic acid having 22 or less carbon atoms. It is more preferably a carboxylic acid residue, and even more preferably an aliphatic monocarboxylic acid residue having 3 or less carbon atoms. In addition, an aliphatic monocarboxylic acid residue having 2 or more carbon atoms is preferable, and an aliphatic monocarboxylic acid residue having 2 carbon atoms is particularly preferable.

One aspect of the polycondensation ester is a polycondensation ester in which the aliphatic diol residue has a carbon number of more than 2.5 and 7.0 or less, and both ends of the polycondensation ester are sealed with monocarboxylic acid residues. Mention may be made of condensed esters.
When the carbon number of the monocarboxylic acid residue sealing both ends of the polycondensed ester is 3 or less, the volatility is lowered, the weight loss due to heating of the polycondensed ester is not increased, and the occurrence of process contamination It is possible to reduce the occurrence of planar failures.
That is, the monocarboxylic acid used for sealing is preferably an aliphatic monocarboxylic acid, more preferably an aliphatic monocarboxylic acid having 2 to 22 carbon atoms, and an aliphatic monocarboxylic acid having 2 to 3 carbon atoms. A carboxylic acid is more preferable, and an aliphatic monocarboxylic acid residue having 2 carbon atoms is particularly preferable.

For example, acetic acid, propionic acid, butanoic acid, benzoic acid and derivatives thereof are preferred, acetic acid or propionic acid is more preferred, and acetic acid is most preferred.
Two or more monocarboxylic acids used for sealing may be mixed.
Both ends of the polycondensed ester are preferably sealed with acetic acid or propionic acid, and most preferably both ends are acetyl ester residues (sometimes referred to as acetyl residues) by acetic acid sealing.

  Specific examples J-1 to J-41 of polycondensed esters are listed in Table 1 below, but the present invention is not limited to these.

  Here, in the abbreviations in Table 1, PA represents phthalic acid, TPA represents terephthalic acid, AA represents adipic acid, SA represents succinic acid, and 2,6-NPA represents 2,6-naphthalenedicarboxylic acid.

The synthesis of the polycondensed ester is carried out by a conventional method, either a polyesterification reaction between a diol and a dicarboxylic acid or a hot melt condensation method using an ester exchange reaction, or an interfacial condensation method between an acid chloride of these acids and a glycol. Easy to synthesize. Polycondensation esters are described in detail in Koichi Murai, “Plasticizers, Theory and Applications” (Sai Shobo Co., Ltd., first edition published on March 1, 1973). It can also be used.
In the present invention, JP-A Nos. 05-155809, 05-155810, JP-A-5-97073, JP-A-2006-259494, JP-A-07-330670, JP-A-2006-342227, JP-A-2007-. The compounds described in each publication of No. 003679 can also be used.

(Carbohydrate derivative plasticizer)
The cellulose acylate film of the present invention preferably further contains a carbohydrate derivative plasticizer. By including a carbohydrate derivative plasticizer, an effect that a cellulose ester film excellent in humidity stability and polarizing plate durability can be obtained.
The carbohydrate derivative plasticizer is preferably a monosaccharide or a carbohydrate derivative containing 2 to 10 monosaccharide units.

The monosaccharide or polysaccharide preferably constituting the carbohydrate derivative plasticizer is characterized in that a substitutable group in the molecule (for example, hydroxyl group, carboxyl group, amino group, mercapto group, etc.) is substituted. Examples of structures formed by substitution include alkyl groups, aryl groups, and acyl groups. Further, an ether structure formed by substitution with an ester structure, an ester structure formed by replacing a hydroxyl group with an acyl group, an amide structure or an imide structure formed by substitution with an amino group, and the like can be given.
Examples of the monosaccharide or carbohydrate containing 2 to 10 monosaccharide units include, for example, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, fructose, mannose, gulose, idose, galactose , Talose, trehalose, isotrehalose, neotrehalose, trehalosamine, caudibiose, nigerose, maltose, maltitol, isomaltose, sophorose, laminaribiose, cellobiose, gentiobiose, lactose, lactosamine, lactitol, lactulose, melibiose, primebelloose, rutiose , Sucrose, sucralose, turanose, vicyanose, cellotriose, cacotriose, gentianose, isomal Triose, isopanose, maltotriose, manninotriose, melezitose, panose, planteose, raffinose, solatriose, umbelliferose, lycotetraose, maltotetraose, stachyose, baltopentaose, velval course, maltohexaose, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, δ-cyclodextrin, xylitol, sorbitol and the like can be mentioned.

  Preferably, ribose, arabinose, xylose, lyxose, glucose, fructose, mannose, galactose, trehalose, maltose, cellobiose, lactose, sucrose, sucralose, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, δ-cyclodextrin Xylitol, sorbitol, more preferably arabinose, xylose, glucose, fructose, mannose, galactose, maltose, cellobiose, sucrose, β-cyclodextrin, γ-cyclodextrin, particularly preferably xylose, glucose, fructose , Mannose, galactose, maltose, cellobiose, sucrose, xylitol, sorbitol.

Examples of the substituent of the carbohydrate derivative plasticizer include an alkyl group (preferably an alkyl group having 1 to 22 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methyl Group, ethyl group, propyl group, hydroxyethyl group, hydroxypropyl group, 2-cyanoethyl group, benzyl group, etc.), aryl group (preferably having 6 to 24 carbon atoms, more preferably 6 to 18 carbon atoms, particularly preferably 6 to 12 carbon atoms). Aryl groups such as phenyl and naphthyl groups, acyl groups (preferably having 1 to 22 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably 2 to 8 carbon atoms, such as acetyl, propionyl, Butyryl, pentanoyl, hexanoyl, octanoyl, benzoyl, toluyl, phthalyl, naphthol, etc.). Further, as a preferred structure formed by substitution with an amino group, an amide structure (preferably an amide having 1 to 22 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as formamide, acetamide, etc. And imide structure (preferably having 4 to 22 carbon atoms, more preferably 4 to 12 carbon atoms, and particularly preferably 4 to 8 carbon atoms, such as succinimide and phthalimide).
Among these, an alkyl group, an aryl group or an acyl group is more preferable, and an acyl group is particularly preferable.

Preferable examples of the carbohydrate derivative plasticizer include the following. However, the carbohydrate derivative plasticizer that can be used in the present invention is not limited to these.
Xylose tetraacetate, glucose pentaacetate, fructose pentaacetate, mannose pentaacetate, galactose pentaacetate, maltose octaacetate, cellobiose octaacetate, sucrose octaacetate, xylitol pentaacetate, sorbitol hexaacetate, xylose tetrapropionate, glucose pentapropioate , Fructose pentapropionate, mannose pentapropionate, galactose pentapropionate, maltose octapropionate, cellobiose octapropionate, sucrose octapropionate, xylitol pentapropionate, sorbitol hexapropionate, Xylose tetrabutyrate, glucose pentab Rate, fructose pentabylate, mannose pentabylate, galactose pentabylate, maltose octabutyrate, cellobiose octabutyrate, sucrose octabutyrate, xylitol pentabylate, sorbitol hexabutyrate, xylose tetrabenzoate, glucose pentabenzoate, Fructose pentabenzoate, mannose pentabenzoate, galactose pentabenzoate, maltose octabenzoate, cellobiose octabenzoate, sucrose octabenzoate, xylitol pentabenzoate, sorbitol hexabenzoate and the like are preferable. Xylose tetraacetate, glucose pentaacetate, fructose pentaacetate, mannose pentaacetate, galactose pentaacetate, maltose octaacetate, cellobiose octaacetate, sucrose octaacetate, xylitol pentaacetate, sorbitol hexaacetate, xylose tetrapropionate, glucose pentapropioate , Fructose pentapropionate, mannose pentapropionate, galactose pentapropionate, maltose octapropionate, cellobiose octapropionate,

Sucrose octapropionate, xylitol pentapropionate, sorbitol hexapropionate, xylose tetrabenzoate, glucose pentabenzoate, fructose pentabenzoate, mannose pentabenzoate, galactose pentabenzoate, maltose octabenzoate, cellobiose octabenzoate, sucrose octabenzoate, Xylitol pentabenzoate, sorbitol hexabenzoate and the like are more preferable. Maltose octaacetate, cellobiose octaacetate, sucrose octaacetate, xylose tetrapropionate, glucose pentapropionate, fructose pentapropionate, mannose pentapropionate, galactose pentapropionate, maltose octapropionate, cellobiose octane Propionate, sucrose octapropionate, xylose tetrabenzoate, glucose pentabenzoate, fructose pentabenzoate, mannose pentabenzoate, galactose pentabenzoate, maltose octabenzoate, cellobiose octabenzoate, sucrose octabenzoate, xylitol pentabenzoate, sorbitol hexabenzoate, etc. Especially Masui.
The carbohydrate derivative plasticizer preferably has a pyranose structure or a furanose structure.

As the carbohydrate derivative used in the present invention, the following compounds are particularly preferred. However, the carbohydrate derivatives that can be used in the present invention are not limited to these.
In the following structural formulas, R each independently represents an arbitrary substituent, and a plurality of R may be the same or different.
In Tables 2 to 5 below, those having eight hydroxyl groups (R are both hydrogen atoms) are acylated with two types of acylating agents, and R introduced with these two types of acylating agents. One of these is represented by “Substituent 1” and the other R is represented by “Substituent 2”, and the degree of substitution represents the number of all eight hydroxyl groups.

  Carbohydrate derivatives are commercially available from Tokyo Kasei Co., Ltd., Aldrich Co., etc., and can easily be obtained by known esterification reactions (for example, the method described in JP-A-8-245678). Can be synthesized.

  The addition amount of these plasticizers is preferably 1 to 20% by mass with respect to cellulose acylate. If the content is 1% by mass or more, the effect of improving the durability of the polarizer can be easily obtained, and if the content is 20% by mass or less, bleeding out hardly occurs. A more preferable addition amount is 2 to 15% by mass, and particularly preferably 5 to 15% by mass.

  The timing for adding these plasticizers to the cellulose acylate film is not particularly limited as long as it is added at the time of film formation. For example, it may be added at the time of cellulose acylate synthesis, or may be mixed with cellulose acylate during dope preparation.

(Other additives)
As other additives, known antioxidants, ultraviolet absorbers, matting agents and the like may be added.
These are described below.

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

(UV absorber)
In the present invention, an ultraviolet absorber may be added to the cellulose acylate solution from the viewpoint of preventing deterioration of the polarizing plate or the liquid crystal. As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties. Examples of the ultraviolet absorber preferably used in the present invention include hindered phenol compounds, hydroxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. .
The hindered phenol compounds include 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl- 4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate and the like.

The benzotriazole compounds include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2,2-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H— Benzotriazol-2-yl) phenol], (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, tri Ethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide ), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 2- (2′-glycine) Droxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) -5-chlorobenzotriazole, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and the like.
The addition amount of these ultraviolet light inhibitors is preferably 1 ppm to 1.0%, more preferably 10 to 1000 ppm by mass in the entire optical film.

(Matting agent)
The cellulose acylate film of the present invention may be added with a matting agent from the viewpoint of film slipperiness and stable production. The matting agent may be an inorganic compound matting agent or an organic compound matting agent.
The inorganic compound matting agent is an inorganic compound containing silicon (for example, silicon dioxide, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, etc.), titanium oxide, zinc oxide, aluminum oxide, barium oxide. Zirconium oxide, strong oxide, antimony oxide, tin oxide, tin oxide / antimony oxide, calcium carbonate, talc, clay, calcined kaolin, calcium phosphate, etc., more preferably silicon-containing inorganic compounds and zirconium oxide. Since the turbidity of the acylate film can be reduced, silicon dioxide is particularly preferably used.

As the fine particles of silicon dioxide, commercially available products having a trade name such as Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.) can be used. As the fine particles of zirconium oxide, for example, those commercially available under trade names such as Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) can be used.
For example, the organic compound matting agent is preferably a polymer such as a silicone resin, a fluorine resin, and an acrylic resin, and among them, a silicone resin is preferable. Of the silicone resins, those having a three-dimensional network structure are particularly preferable. A commercial product having a trade name can be used.

When these matting agents are added to the cellulose acylate solution, the method is not particularly limited, and there is no problem as long as a desired cellulose acylate solution can be obtained by any method. For example, an additive may be contained at the stage of mixing cellulose acylate and a solvent, or an additive may be added after preparing a mixed solution with cellulose acylate and a solvent.
Further, it may be added and mixed immediately before casting the dope, which is a so-called immediately preceding addition method, and the mixing is used by installing screw-type kneading online. Specifically, a static mixer such as an in-line mixer is preferable, and the in-line mixer is, for example, a static mixer SWJ (Toray static type in-pipe mixer Hi-Mixer) (manufactured by Toray Engineering). Is preferred.

  In addition, regarding in-line addition, in order to eliminate density unevenness, particle aggregation, and the like, Japanese Patent Application Laid-Open No. 2003-053752 mixes additive liquids having different compositions into the main raw material dope in a method for producing a cellulose acylate film. A method is described in which the distance L between the tip of the addition nozzle and the start end of the in-line mixer is 5 times or less of the main raw material pipe inner diameter d, thereby eliminating density unevenness and aggregation of matte particles. As a more preferred embodiment, the distance (L) between the tip opening of the additive liquid supply nozzle having a composition different from that of the main raw material dope and the starting end of the in-line mixer is 10 times or less the inner diameter (d) of the supply nozzle tip opening. And that the in-line mixer is a static unstirred in-tube mixer or a dynamic agitated in-tube mixer. More specifically, it is disclosed that the flow rate ratio of the cellulose acylate film main raw material dope / in-line additive solution is 10/1 to 500/1, preferably 50/1 to 200/1. Furthermore, an additive is also added to Japanese Patent Application Laid-Open No. 2003-014933 which aims at a retardation film with little additive bleed-out, no delamination phenomenon, excellent slipperiness and excellent transparency. As a method, it may be added to the dissolving kettle, or a solution in which additives or additives are dissolved or dispersed between the melting kettle and the co-casting die may be added to the dope being fed. In the latter case, it is described that it is preferable to provide a mixing means such as a static mixer in order to improve the mixing property.

  If the matting agent is not added in a large amount, the haze of the film does not increase. When actually used in an LCD, inconveniences such as a decrease in contrast and generation of bright spots are unlikely to occur. If the amount is too small, the above-mentioned creaking and scratch resistance can be realized. From these viewpoints, it is particularly preferable to include the cellulose acylate in a proportion of 0.05 to 1.0% by mass.

  In the total solid content, the sum of the constituent ratios of cellulose acylate, plasticizer, and other additives is 100% by mass.

<4 Structure and physical properties of cellulose acylate film>
(Layer structure of film)
The cellulose acylate film of the present invention may be a single layer or a laminate of two or more layers.
When the cellulose acylate film of the present invention is a laminate of two or more layers, a two-layer structure or a three-layer structure is more preferable, and a three-layer structure is preferable. In the case of a three-layer structure, a layer in contact with the metal support (hereinafter also referred to as a support surface or a skin B layer) when the film of the present invention is produced by solution casting, and the side opposite to the metal support It is preferable to have an air interface layer (hereinafter also referred to as an air surface or a skin A layer) and a single core layer (hereinafter also referred to as a base layer) sandwiched therebetween. That is, the film of the present invention preferably has a three-layer structure of skin B layer / core layer / skin A layer.
The skin A layer and the skin B layer are collectively referred to as a skin layer (or surface layer).

  In the cellulose acylate film of the present invention, the acyl substitution degree of the cellulose acylate in each layer may be uniform, or a plurality of cellulose acylates may be mixed in one layer, but the cellulose acylate in each layer It is preferable from the viewpoint of adjusting optical properties that the acyl substitution degree is all constant. In addition, when the cellulose acylate film of the present invention has a three-layer structure, it is preferable from the viewpoint of production cost that the cellulose acylate contained in the surface layers on both sides is a cellulose acylate having the same acyl substitution degree.

(Elastic modulus)
The film of the present invention exhibits a practically sufficient elastic modulus. The range of the elastic modulus is not particularly limited, but is preferably 1.0 GPa to 5.0 GPa, and more preferably 2.0 GPa to 4.5 GPa from the viewpoints of manufacturability and handling properties. The compound represented by the general formula (I) of the present invention has the effect of improving the elastic modulus by hydrophobizing the film by being added to the cellulose acylate, which is also an advantage in the present invention. is there.

(Photoelastic coefficient)
The absolute value of the photoelastic coefficient of the film of the present invention is preferably 8.0 × 10 ⁻¹² m ² / N or less, more preferably 6 × 10 ⁻¹² m ² / N or less, and further preferably 5 × 10 ^−12. m ² / N or less. By reducing the photoelastic coefficient of the resin film, it is possible to suppress the occurrence of unevenness under high temperature and high humidity when the resin film is incorporated into a liquid crystal display device as a polarizing plate protective film. The photoelastic coefficient is measured and calculated by the following method unless otherwise specified.
The lower limit value of the photoelastic modulus is not particularly limited, but is practically 0.1 × 10 ⁻¹² m ² / N or more.

  The film was cut into 3.5 cm x 12 cm, and the Re at each load of 250 g, 500 g, 1000 g, and 1500 g was measured with an ellipsometer (M150 [trade name], JASCO Corporation), and the Re change with respect to the stress. The photoelastic coefficient is measured by calculating from the slope of the straight line.

(Moisture content)
The moisture content of the resin 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 in 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 of the film of the present invention at 25 ° C. and a relative humidity of 80% is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably less than 3% by mass. By reducing the moisture content of the film, when the resin film is incorporated as a polarizing plate protective film in a liquid crystal display device, display unevenness of the liquid crystal display device under high temperature and high humidity can be made difficult to occur. The lower limit of the moisture content is not particularly limited, but is practically 0.1% by mass or more.

(Moisture permeability)
The moisture permeability of the resin film is determined according to the moisture permeability test (cup method) of JIS Z0208, and the mass of water vapor passing through a sample with an area of 1 m ² in 24 hours in an atmosphere at a temperature of 60 ° C. and a relative humidity of 95% RH is measured. Can be evaluated.
Moisture permeability of the resin film of the present invention is preferably 500~2000g ^/ m 2 · day, it is more preferably ^{900~1300g / m 2 · day, 1000~1200g} / m 2 · day Is particularly preferred.

(Haze)
The cellulose acylate film of the present invention preferably has a haze of 1.1% or less, more preferably 1.0% or less, still more preferably 0.7% or less, and 0.5% It is particularly preferred that By setting the haze to the upper limit value or less, there is an advantage that the transparency of the film becomes higher and it becomes easier to use as an optical film. Unless otherwise specified, haze is measured and calculated by the method employed in Examples described later. The lower limit of haze is not particularly limited, but is practically 0.001% or more.

(Film thickness)
10-100 micrometers is preferable, as for the average film thickness of the cellulose acylate film of this invention, 15-80 micrometers is more preferable, and 20-70 micrometers is more preferable. By setting it to 20 μm or more, the handling property when producing a web-like film is improved, which is preferable. Moreover, by setting it as 70 micrometers or less, it is easy to respond to a humidity change and it is easy to maintain an optical characteristic.
In addition, when the cellulose acylate film of the present invention has a laminated structure of three or more layers, the thickness of the core layer is preferably 3 to 70 μm, more preferably 5 to 60 μm. When the film of the present invention has a laminated structure of three or more layers, the thickness of the surface layers (skin A layer and skin B layer) on both sides of the film is more preferably 0.5 to 20 μm, particularly 0.5 to 10 μm. Preferably, 0.5 to 3 μm is most preferable.

(Film width)
The cellulose acylate film of the present invention preferably has a film width of 700 to 3000 mm, more preferably 1000 to 2800 mm, and particularly preferably 1300 to 2500 mm.

<5 Method for producing cellulose acylate film>
The cellulose acylate film of the present invention is preferably produced by a solvent cast method. Examples of production of a cellulose acylate film using a solvent cast method are described in U.S. Pat. Nos. 2,336,310, 2,367,603, 2,492,078, and 2,492. No. 977, No. 2,492,978, No. 2,607,704, No. 2,739,069 and No. 2,739,070, British Patent No. 640731 and Refer to each specification of No. 736892, and Japanese Patent Publication Nos. 45-4554, 49-5614, JP-A-60-176634, 60-203430 and 62-1115035. Can do. The cellulose acylate film may be subjected to a stretching treatment. With respect to the stretching method and conditions, for example, refer to JP-A-62-115035, JP-A-4-152125, 4-284221, 4-298310, and 11-48271. can do.

(Casting method)
As a solution casting method, a method in which the prepared dope is uniformly extruded from a pressure die onto a metal support, and a method using a doctor blade in which the dope once cast on the metal support is adjusted with a blade is used. Although there is a method using a reverse roll coater that adjusts with a reverse rotating roll, a method using a pressure die is preferred. The pressure die includes a coat hanger type and a T die type, and any of them can be preferably used. In addition to the methods mentioned here, it can be carried out by various known methods for casting a cellulose triacetate solution, and each condition is set in consideration of differences in the boiling point of the solvent used. Thus, the same effects as those described in the respective publications can be obtained.

-Co-casting In the formation of the cellulose acylate film of the present invention, it is preferable to use a co-casting method, a sequential casting method, a lamination casting method such as a coating method, particularly using a simultaneous co-casting method, It is particularly preferable from the viewpoint of stable production and production cost reduction.
When manufacturing by the co-casting method and the sequential casting method, first, a cellulose acetate solution (dope) for each layer is prepared. In the co-casting method (multi-layer simultaneous casting), a casting dope for each layer (which may be three layers or more) is simultaneously pressed from a separate slit or the like on a casting support (band or drum). This is a casting method in which the dope is extruded from the casting gies to be cast, and each layer is cast at the same time, peeled off from the support at an appropriate time, and dried to form a film. FIG. 2 is a cross-sectional view showing a state in which the co-casting giesser 3 is used to simultaneously extrude and cast the surface layer dope 1 and the core layer dope 2 on the casting support 4.

  In the sequential casting method, the casting dope for the first layer is first extruded from the casting giusa on the casting support, cast, and dried on the second layer without drying or drying. Extrude the casting dope for casting from the casting gieser, cast the dope sequentially to the third layer or more, if necessary, peel it off from the support at an appropriate time, and dry it. This is a casting method for forming a film. In general, the core layer film is formed into a film by a solution casting method to prepare a coating solution to be applied to the surface layer, and then applied to the film one side at a time or both sides simultaneously using an appropriate applicator. This is a method of forming a film having a laminated structure by applying and drying a liquid.

The endlessly running metal support used to manufacture the cellulose acylate film includes a drum whose surface is mirror-finished by chrome plating and a stainless steel belt whose surface is mirror-finished by surface polishing (may be called a band) ) Is used. One or more pressure dies may be installed above the metal support. Preferably 1 or 2 groups. When two or more are installed, the amount of dope to be cast may be divided into various ratios for each die, or the dope may be fed to the dies from each of a plurality of precision quantitative gear pumps. The temperature of the dope (resin solution) used for casting is preferably −10 to 55 ° C., more preferably 25 to 50 ° C. In that case, all solution temperatures in the process may be the same or may be different in each part of the process. If they are different, the temperature may be a desired temperature just before casting.
Moreover, there is no restriction | limiting in particular about the material of the said metal support body, However, It is more preferable that it is a product made from SUS (for example, SUS316).

(Peeling)
The method for producing a cellulose acylate film of the present invention preferably includes a step of peeling the dope film from the metal support. There is no restriction | limiting in particular about the peeling method in the manufacturing method of a cellulose acylate film, When a well-known method is used, peelability can be improved.

(Extension process)
In the manufacturing method of the cellulose acylate film of this invention, it is preferable to include the process of extending | stretching formed into a film. The stretching direction of the cellulose acylate film is preferably either the film conveying direction or the direction (lateral direction) orthogonal to the conveying direction, but the direction orthogonal to the film conveying direction (lateral direction) is used for the subsequent film. This is particularly preferable from the viewpoint of the polarizing plate processing process.

  The method of stretching in the transverse direction is described in, for example, JP-A-62-115035, JP-A-4-152125, 4-284221, 4-298310, and 11-48271. Yes. 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 transverse direction, the film can also be stretched by conveying the film while holding it 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).

  When the cellulose acylate film of the present invention is used as a protective film for a polarizer, in order to suppress light leakage when the polarizing plate is viewed obliquely, the transmission axis of the polarizer and the in-plane of the resin film of the present invention Need to be arranged in parallel. Since the transmission axis of the roll film-like polarizer produced continuously is generally parallel to the width direction of the roll film, it is composed of the roll film-like polarizer and the roll film-like cellulose acylate film. In order to continuously bond the protective film, the in-plane slow axis of the roll film-shaped protective film needs to be parallel to the width direction of the film. Therefore, it is preferable to stretch more in the width direction. The stretching process may be performed in the middle of the film forming process, or the original fabric that has been formed and wound may be stretched.

  Stretching in the transverse direction is preferably 5 to 100%, more preferably 5 to 80%, particularly preferably 5 to 40%. In addition, the stretching process may be performed in the middle of the film forming process, or the raw film that has been formed and wound may be stretched. In the former case, stretching may be performed in a state including the residual solvent amount, and the residual solvent amount = (residual volatile matter mass / heat-treated film mass) × 100% is preferably stretched at 0.05 to 50%. be able to. It is particularly preferable to perform 5 to 80% stretching in a state where the residual solvent amount is 0.05 to 5%.

(Dry)
In the manufacturing method of the cellulose acylate film of this invention, the process of drying a cellulose acylate film and the process of extending | stretching the resin film of this invention after drying at the temperature of glass transition temperature (Tg) -10 degreeC or more are included. Is preferable from the viewpoint of retardation development.

  The dope drying on the metal support involved in the production of the cellulose acylate film of the present invention is generally performed from the surface side of the metal support (drum or belt), that is, from the surface of the web on the metal support. A method in which hot air is applied, a method in which hot air is applied from the back of the drum or belt, a temperature-controlled liquid is brought into contact with the back of the belt or drum opposite the dope casting surface, and the drum or belt is heated to transfer the surface to the surface. Although there is a back surface liquid heat transfer method for controlling the temperature, the back surface liquid heat transfer method is preferable. The surface temperature of the metal support before casting may be any number as long as it is not higher than the boiling point of the solvent used for the dope. However, in order to promote drying and to lose fluidity on the metal support, the temperature should be set to 1 to 10 ° C. lower than the boiling point of the lowest boiling solvent. Is preferred. This is not the case when the cast dope is cooled and peeled off without drying.

  The film thickness may be adjusted by adjusting the solid content concentration contained in the dope, the slit gap of the die base, the extrusion pressure from the die, the metal support speed, and the like so as to obtain a desired thickness.

  The length of the cellulose acylate film obtained as described above is preferably wound at 100 to 10,000 m per roll, more preferably 500 to 7000 m, and still more preferably 1000 to 6000 m. When winding, it is preferable to give knurling to at least one end, the knurling width is preferably 3 mm to 50 mm, more preferably 5 mm to 30 mm, and the height is preferably 0.5 to 500 μm, more preferably 1 to 200 μm. is there. This may be a single push or a double push.

  In general, in a large-screen display device, since the contrast reduction and coloration in an oblique direction become remarkable, the cellulose acylate film of the present invention is particularly suitable for use in a large-screen liquid crystal display device. When used as an optical compensation film for a large-screen liquid crystal display device, for example, the film width is preferably set to 1470 mm or more. In addition, the polarizing plate protective film of the present invention is produced not only in the form of a film piece cut into a size that can be incorporated into a liquid crystal display device as it is, but also in a long shape by continuous production. The film of the aspect wound up in the shape is also included. The polarizing plate protective film of the latter mode is stored and transported in that state, and is cut into a desired size and used when it is actually incorporated into a liquid crystal display device or bonded to a polarizer or the like. Similarly, it is cut into a desired size when it is actually incorporated into a liquid crystal display device after being bonded to a polarizer or the like made of a polyvinyl alcohol film or the like that has been made into a long shape. Used. As one mode of the optical compensation film wound up in a roll shape, a mode in which the roll length is rolled up to 2500 m or more can be mentioned.

<< Polarizing plate >>
The polarizing plate of this invention has a polarizer and the cellulose acylate film of this invention at least.
The polarizing plate of the present invention preferably has a polarizer and the film of the present invention on one or both sides of the polarizer. Examples of the polarizer include an iodine polarizer, a dye polarizer using a dichroic dye, and a polyene polarizer. The iodine polarizer and the dye polarizer are generally produced using a polyvinyl alcohol film. When the cellulose acylate film of the present invention is used as a polarizing plate protective film, the method for producing the polarizing plate is not particularly limited, and can be produced by a general method. There is a method in which the obtained cellulose acylate film is treated with an alkali and bonded to both sides of a polarizer prepared by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Instead of alkali treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be performed. Examples of the adhesive used to bond the protective film-treated surface and the polarizer include polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, vinyl latexes such as butyl acrylate, and the like.

  The cellulose acylate film of the present invention is preferably bonded to the polarizer so that the transmission axis of the polarizer and the slow axis of the cellulose acylate film of the present invention are substantially orthogonal. In the liquid crystal display device of the present invention, it is preferable that the transmission axis of the polarizing plate and the slow axis of the cellulose acylate film of the present invention are substantially orthogonal. Here, being substantially orthogonal means that the direction of the main refractive index nx of the cellulose acylate film of the present invention and the direction of the transmission axis of the polarizing plate intersect at an angle of 90 ° ± 10 °. However, it is preferable that they intersect at an angle of 90 ° ± 5 °, more preferably at an angle of 90 ° ± 1 °. By setting it as the said range, the light omission under polarizing plate cross Nicol can be reduced more.

  The polarizing plate of the present invention is produced not only in the form of a film piece cut into a size that can be incorporated into a liquid crystal display device as it is, but also in a long shape by continuous production and wound up into a roll. The polarizing plate of the aspect (for example, roll length 2500m or more or 3900m or more aspect) is also included. In order to use for a large-screen liquid crystal display device, the width of the polarizing plate is preferably 1470 mm or more. The specific configuration of the polarizing plate of the present invention is not particularly limited, and a known configuration can be employed. For example, the configuration described in FIG. 6 of JP-A-2008-262161 can be employed.

<< Liquid Crystal Display >>
The liquid crystal display device of the present invention has a liquid crystal cell and the polarizing plate of the present invention.
The liquid crystal display device of the present invention is a liquid crystal display device having a liquid crystal cell and a pair of polarizing plates disposed on both sides of the liquid crystal cell, wherein at least one of the polarizing plates is an IPS, OCB or A VA mode liquid crystal display device is preferable. The internal structure of a typical liquid crystal display device is shown in FIG. There is no restriction | limiting in particular as a concrete structure of the liquid crystal display device of this invention, A well-known structure is employable. Further, the configuration described in FIG. 2 of JP-A-2008-262161 can also be preferably employed.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not construed as being limited thereto.

(Synthesis example)
(Synthesis Example 1: Synthesis of A-1)
In a 300 mL three-necked flask equipped with a mechanical stirrer, thermometer, condenser, and dropping funnel, 54 g of p-cresol, 5.9 g of activated clay, and 0.07 g of oxalic acid were weighed and stirred at 90 ° C. under a nitrogen stream. Styrene 104.1g was added over 6 hours, and also it stirred at 90 degreeC for 1 hour. The reaction solution was returned to room temperature, diluted with 1 L of ethyl acetate, and the organic layer was washed with water and saturated brine. The obtained organic layer was dried over magnesium sulfate and concentrated to give a brown oil. The brown oil was purified with a silica gel column (hexane / ethyl acetate = 10/1), and the resulting colorless oil was dried in vacuo at 80 ° C. for 2 hours to give the desired exemplified compound A-1 as a colorless oil. (33.0 g).

(Synthesis Example 2: Synthesis of A-2)
In the same manner as in Synthesis Example 1, except that p-cresol was changed to 75 g of p-tert-butylphenol, the target Exemplified Compound A-2 was obtained as a colorless oil (21.0 g).

(Synthesis Example 3: Synthesis of A-3)
In the same manner as in Synthesis Example 1, except that p-cresol was changed to 103 g of p-tert-octylphenol, the target Exemplified Compound A-3 was obtained as a colorless oil (24.0 g).

(Synthesis Example 4: Synthesis of A-4)
In the same manner as in Synthesis Example 1 except that p-cresol was changed to 88 g of p-cyclohexylphenol, the target Exemplified Compound A-4 was obtained as a white amorphous solid (25.4 g).

(Synthesis Example 5: Synthesis of A-5)
In the same manner as in Synthesis Example 1, except that p-cresol was changed to 117 g of p-decylphenol, the target Exemplified Compound A-5 was obtained as a colorless oil (36.0 g).

(Synthesis Example 6: Synthesis of A-7)
In the same manner as in Synthesis Example 1, except that styrene was changed to 118 g of β-methylstyrene, the target Exemplified Compound A-7 was obtained as a yellow oil (12 g).

(Synthesis Example 7: Synthesis of A-8)
In the same manner as in Synthesis Example 1, except that p-cresol was changed to 103 g of p-octylphenol and the addition amount of styrene was changed to 27 g, the target Exemplified Compound A-8 was obtained as a yellow oil (11 g).

(Synthesis Example 8: Synthesis of A-9)
In the same manner as in Synthesis Example 1 except that p-cresol was changed to 61 g of 2,6-dimethylphenol, the target Exemplified Compound A-9 was obtained as a colorless oil (31 g).

  Exemplified compounds A-6 and A-19 were also synthesized by the above method or a known method.

Example 1
(1) Film formation of cellulose acylate film (preparation of cellulose acylate)
A cellulose acylate having an acetyl substitution degree of 2.87 was prepared. This was carried out by adding sulfuric acid (7.8 parts by mass with respect to 100 parts by mass of cellulose) as a catalyst, adding carboxylic acid as a raw material for the acyl substituent, and carrying out an acylation reaction at 40 ° C. In addition, aging was performed at 40 ° C. after acylation. Further, the low molecular weight component of the cellulose acylate was removed by washing with acetone.

(Preparation of dope solution for air side surface layer)
-Preparation of cellulose acylate solution The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acylate solution.

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Composition of cellulose acylate solution ――――――――――――――――――――――――――――――――――――
Cellulose acetate with an acetyl substitution degree of 2.87 and a polymerization degree of 370
100.0 parts by mass Daipet Kogyo Monopet (registered trademark) SB (plasticizer)
9.0 parts by weight SAIB-100 (plasticizer) manufactured by Eastman Chemical Co., Ltd. 3.0 parts by weight Exemplary Compound A-1 4.0 parts by weight Methylene chloride (first solvent) 353.9 parts by weight Methanol (second solvent) ) 89.6 parts by mass n-butanol (third solvent) 4.5 parts by mass ――――――――――――――――――――――――――――――― ――――

  Monopet (registered trademark) SB manufactured by Daiichi Kogyo Kagaku is benzoic acid ester of sucrose, and SAIB-100 manufactured by Eastman Chemical Co. is acetic acid and isobutyric acid ester of sucrose.

-Preparation of matting agent solution The following composition was put into a disperser and stirred to dissolve each component to prepare a matting agent solution.
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Composition of matting agent solution ―――――――――――――――――――――――――――――――――――
Silica particles having an average particle size of 20 nm (AEROSIL R972,
Nippon Aerosil Co., Ltd.) 2.0 parts by weight Methylene chloride (first solvent) 69.3 parts by weight Methanol (second solvent) 17.5 parts by weight n-butanol (third solvent) 0.9 parts by weight The cellulose Acylate solution 0.9 parts by mass ―――――――――――――――――――――――――――――――――――

  1.3 parts by mass of the matting agent solution and 98.7 parts by mass of the cellulose acylate solution were added and mixed using an in-line mixer to prepare an air side surface layer solution.

(Preparation of dope solution for base layer)
-Preparation of cellulose acylate solution The following composition was put into a mixing tank and stirred to dissolve each component to prepare a base layer dope.

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Cellulose acetate with an acetyl substitution degree of 2.87 and a polymerization degree of 370
100.0 parts by mass Daipet Kogyo Monopet (registered trademark) SB (plasticizer)
9.0 parts by weight Eastman Chemical SAIB-100 (plasticizer) 3.0 parts by weight Exemplary Compound A-1 4.0 parts by weight The following ultraviolet absorber (UV-1) 2.0 parts by weight Methylene chloride ( First solvent) 297.7 parts by mass Methanol (second solvent) 75.4 parts by mass n-butanol (third solvent) 3.8 parts by mass --------- ――――――――――――――――――

(Preparation of dope solution for support surface layer)
For the support side surface layer, 1.3 parts by weight of the matting agent solution prepared at the time of preparing the air layer side surface layer dope and 99.3 parts by weight of the cellulose acylate solution were mixed using an in-line mixer. A solution was prepared.

(Casting)
Using a drum casting apparatus, the base layer dope liquid prepared as described above, the air side surface dope liquid on one of the both sides, and the support side surface dope liquid on the other side are cast simultaneously in three layers made of stainless steel. The film was uniformly cast from a casting port on a support (support temperature −9 ° C.). Stripped in a state where the amount of residual solvent in the dope of each layer is about 70% by mass, fixed both ends in the width direction of the film with a pin tenter, and 1.28 in the lateral direction in a state of residual solvent amount of 3-5% by mass. The film was dried while being stretched twice. Then, it further dried by conveying between the rolls of a heat processing apparatus, and obtained the cellulose acylate film 101 of this invention. The obtained cellulose acylate film 101 had a thickness of 60 μm and a width of 1480 mm.

  In the cellulose acylate film 101, the present invention is the same as the cellulose acylate film 101 except that it is changed to the compound shown in Table 6 described later in equimolar amounts with the exemplified compound A-1 instead of the exemplified compound A-1. Cellulose acylate films 102 to 110 and comparative cellulose acylate films c11 to c13 were produced.

  Furthermore, in the cellulose acylate films 101, 102, and c13, 12 parts by mass of the following polycondensation polymer (A), which is a polycondensation ester plasticizer, was added instead of Monopet (registered trademark) SB and SAIB-100. The cellulose acylate films 101, 202 of the present invention and the comparative cellulose acylate film c21 were produced in the same manner as the cellulose acylate films 101, 102, c13, respectively.

  Polycondensation polymer (A): Polyester composed of adipic acid and ethanediol (terminal hydroxyl group) (number average molecular weight = 1000)

Each cellulose acylate film was evaluated for moisture permeability, haze, and film yellow coloration.
The obtained results are collectively shown in Table 6 described later.
In addition, these cellulose acylate films are also called a polarizing plate protective film below.

[Evaluation]
(Evaluation of film moisture permeability)
According to the moisture permeability test (cup method) of JIS Z0208, the mass of water vapor passing through a cellulose acylate film cut out in an area of 1 m ² in an atmosphere of a temperature of 60 ° C. and a relative humidity of 95% RH was measured for 24 hours.

AA: moisture permeability is 1100g / ^m 2 · day under A: moisture permeability is 1100 or higher 1200g / ^m 2 · day less B: moisture permeability is over 1200 1300g / ^m 2 · day less than C: moisture permeability 1300 g / ^{m 2} · more than day

(Evaluation of thermal coloring of film)
About each polarizing plate protective film, hue b ^* was measured using the spectrophotometer UV3150 of Shimadzu Corporation before and after storing for 72 hours in an environment of 105 ° C. Here, when the value of the hue b ^* increases to the minus side, the transmitted light has a blue tint, and when the value of the hue b ^* increases to the plus side, the yellow tint increases.
The measurement results were evaluated according to the following criteria.

AA: The value of b ^* is 0 or more and less than 0.5 A: The value of b ^* is 0.5 or more and less than 0.8 B: The value of b ^* is 0.8 or more and less than 1.0 C: The value of b ^* is 1.0 or more

  In Table 6 described below, the hue before thermal storage is displayed as thermal coloring (Fr), and the hue after thermal storage is displayed as thermal coloring (3 day).

(Evaluation of film haze)
Using a haze meter (HGM-2DP, Suga Tester), measurement was performed according to JIS K-6714. Each polarizing plate protective film was cut out into 40 mm x 80 mm, and this was measured on the conditions of 25 degreeC and relative humidity 60% RH.
Moreover, after preserve | saving for 72 hours on 105 degreeC and the conditions of relative humidity 10% RH, the film haze was measured on the conditions similar to the above.
In Table 6 described later, the haze before storage is displayed as Fr, and the haze after storage is displayed as time.
The measurement results were evaluated according to the following criteria.

A: Haze is 0% to less than 1% B: Haze is 1% to less than 5% C: Haze is 5% or more

Example 2
(2) Production of polarizing plate [saponification treatment of polarizing plate protective film]
The polarizing plate protective film 101 which is the cellulose acylate film produced in Example 1 was immersed in a 2.3 mol / L sodium hydroxide aqueous solution at 55 ° C. for 3 minutes. It wash | cleaned in the room temperature water-washing bath, and neutralized using 0.05 mol / L sulfuric acid at 30 degreeC. The film was washed again in a water bath at room temperature, dried with warm air at 100 ° C., and a saponified polarizing plate protective film 101 was obtained.

(Production of polarizer)
After immersing a 75 μm thick polyvinyl alcohol film made of polyvinyl alcohol having an average polymerization degree of about 2400 and a saponification degree of 99.9 mol% or more in pure water at 30 ° C., the mass ratio of iodine / potassium iodide / water is 0. It was immersed in an aqueous solution of 02/2/100 at 30 ° C. Then, it immersed at 56.5 degreeC in the aqueous solution whose mass ratio of potassium iodide / boric acid / water is 12/5/100. Subsequently, the film was washed with pure water at 8 ° C. and then dried at 65 ° C. to obtain a polarizing film in which iodine was adsorbed and oriented on a polyvinyl alcohol film. Stretching was mainly performed in the iodine staining and boric acid treatment steps, and the total stretching ratio was 5.3 times.

[Bonding of polarizer and polarizing plate protective film]
The saponified polarizing plate protective film 101 was attached to one side of the polarizer produced as described above using a polyvinyl alcohol-based adhesive.
The same saponification treatment was performed on a commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Film Co., Ltd.). A commercially available cellulose triacetate film after saponification treatment was attached to the surface of the polarizer opposite to the side on which the produced polarizing plate protective film was attached using a polyvinyl alcohol-based adhesive. The commercially available cellulose triacetate film has a film thickness of 80 μm and a moisture permeability of 400 g / m ² · day.
At this time, the polarizer was arranged so that the transmission axis of the polarizer and the slow axis of the saponified polarizing plate protective film 101 were parallel to each other. Further, the transmission axis of the polarizer and the slow axis of the commercially available cellulose triacetate film after saponification treatment were arranged so as to be orthogonal to each other.
Thus, the polarizing plate 101 of the present invention was produced.

The polarizing plate protective films 102 to 110, 201 and 201 of the present invention and the comparative polarizing plate protective films c11 to c13 and c21 were also saponified and bonded in the same manner as the polarizing plate 101, respectively. Polarizing plates 102 to 110, 201 and 201 and comparative polarizing plates c11 to c13 and c21 were produced.
Thus, durability of each produced polarizing plate was evaluated.

[Evaluation]
(Evaluation of polarizer durability of polarizing plate)
For each polarizing plate, the orthogonal transmittance CT of the polarizer at a wavelength of 410 nm was measured using UV3100PC (manufactured by Shimadzu Corporation), and the average value of the values measured repeatedly 10 times was used.
The polarizer durability test of the polarizing plate was performed as follows in a form in which each polarizing plate was attached to glass with an adhesive. Two samples (about 5 cm × 5 cm) each having a polarizing plate attached on glass were prepared. In the single-plate orthogonal transmittance measurement, the film side of this sample is set facing the light source and measured. Two samples were measured respectively, and the average value was taken as the orthogonal transmittance of the polarizing plate.
Then, after storing for 336 hours in an environment of 80 ° C. and a relative humidity of 90% RH, the orthogonal transmittance was measured in the same manner as described above. The change in orthogonal transmittance before and after aging was determined, and this was evaluated as the polarizer durability according to the following criteria.
In addition, the relative humidity in the environment without humidity control was in the range of 0 to 20% RH.

AA: Less than 0.6% A: 0.6-1.0%
B: Over 1.0% and 1.1% or less C: Over 1.1%

  The results obtained are summarized in Table 6 below.

  In addition, the comparison compound H-1 is Sumitomo Chemical's Sumilizer GM, H-2 is Sumitomo Chemical's Sumitizer MDP-S, and H-3 is BASF's Irganox 1010, which has the following structure.

As apparent from Table 6 above, each polarizing plate protective film of the present invention has low moisture permeability, and is less susceptible to haze, yellowing, and polarizer durability compared to known antioxidants. Was also found to be good.
In the known antioxidant, although the moisture permeability is low, either the haze or the yellow coloring is large and the polarizer durability of the polarizing plate is poor.
Thus, the use of the compound of the present invention solved the problem that haze and yellow coloration were simultaneously reduced, the polarizer durability was excellent, and that it was difficult to obtain with known antioxidants.

Example 3
(3) Production of liquid crystal display device The polarizing plate of the present invention using the polarizing plate protective film 101 produced in Example 1 by peeling off the polarizing plate on the viewer side of a commercially available liquid crystal television (BRAVIA J5000 of Sony Corporation). 201 was attached via an adhesive such that the polarizing plate protective film 101 was on the liquid crystal cell side (film 31b in FIG. 1), and a liquid crystal display device 301 was produced. Here, the transmission axis of the polarizing plate on the viewer side is arranged in the vertical direction. The state at this time is as shown in the schematic diagram shown in FIG. 1, and the liquid crystal display device 301 manufactured here has a light source 26, a light guide plate 25, a first polarizing plate 21A (polarizer 32, polarized light) from the lower side of the drawing. Film 31a, 31b), an array substrate 24 having an alignment film and a transparent electrode, a liquid crystal layer 23, a color filter substrate 22 having an alignment film and a transparent electrode, and a polarizing plate 21B. As described above, the polarizing plate protective film 31b of the second polarizing plate 21B is also replaced with the polarizing plate protective film of the present invention / comparison. At this time, it was arrange | positioned so that the extending | stretching direction of a polarizing plate protective film and the polarizing direction R of a polarizing plate might correspond.

  Further, except that the polarizing plate protective film 101 is replaced with the polarizing plate protective films 102-110, 201, 202, c11-c13, c21, the liquid crystal display devices 302-310, 401, 402 and comparative liquid crystal display devices c31 to c33 and c41 were produced.

  Each of the liquid crystal display devices thus produced was left to stand for 24 hours in an environment of 60 ° C. and 90% RH, and when the display unevenness was confirmed, all of the liquid crystal display devices of the present invention were comparative polarizing plate protective films. Compared with a liquid crystal display device using the above, it has been found that there is no unevenness or the occurrence area of the unevenness is small and excellent.

DESCRIPTION OF SYMBOLS 1 Surface layer dope 2 Core layer dope 3 Co-casting gissa 4 Casting support 21A, 21B Polarizing plate 22 Color filter substrate 23 Liquid crystal layer 24 Array substrate 25 Light guide plate 26 Light source 31a, 31b Cellulose acylate film (polarizing plate Protective film)
32 Polarizer

Claims (17)

A cellulose acylate film containing at least one compound represented by the following general formula (I) and cellulose acylate.

[In General Formula (I), R ¹ represents an unsubstituted linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, and R ² and R ³ each independently represent a hydrogen atom, 1 to 6 carbon atoms. R ⁴ represents an unsubstituted alkyl group having 1 to 6 carbon atoms, and Ar ¹ represents a substituted or unsubstituted aromatic group. m represents an integer of 0 to 3, and n represents an integer of 1 to 4. However, when n is 1, Ar ¹ represents an unsubstituted aromatic group. ] The cellulose acylate film according to claim 1, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (IA).

[In the general formula ^{(IA), R 1, R} 2, R 4, Ar 1, m and n are, in ^{R 1, R 2, R 4} , Ar 1, m and n as defined in the general formula (I) is there. ] The cellulose acylate film according to claim 2, wherein the compound represented by the general formula (IA) is a compound represented by the following general formula (IB).

[In the general formula (IB), ^{R 1} and Ar ¹ have the same meanings as ^{R 1} and Ar ¹ in the general formula (I). R ^2a and R ^2b each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Ar ^1a has the same meaning as Ar ¹ . ] The cellulose acylate film according to claim 3, wherein the compound represented by the general formula (IB) is a compound represented by the following general formula (IC).

[In the general formula (IC), ^{R 1} and Ar ¹ have the same meanings as ^{R 1} and Ar ¹ in the general formula (I). Ar ^1a has the same meaning as Ar ¹ . ] The cellulose acylate film according to claim 1, wherein R ¹ is an unsubstituted linear, branched or cyclic alkyl group having 1 to 8 carbon atoms. The cellulose acylate film according to claim 1, wherein R ¹ is a methyl group or a tert-butyl group. The cellulose acylate film according to any one of claims 1 to 6, wherein the acyl substitution degree (A) of the cellulose acylate satisfies the following formula.
1.5 ≦ A ≦ 3.0 The cellulose acylate film according to any one of claims 1 to 7, wherein a degree of acetyl substitution (B) of the cellulose acylate satisfies the following formula.
2.0 ≦ B ≦ 3.0   Furthermore, the cellulose acylate film of any one of Claims 1-8 which contains at least 1 sort (s) of a polycondensation ester compound as a plasticizer. The polycondensation ester compound is obtained by polycondensation of at least one dicarboxylic acid represented by the following general formula (a) and at least one diol represented by the following general formula (b). The cellulose acylate film described.
Formula (a)
_{HOC (= O) -X-CO} 2 H
General formula (b)
HO-Z-OH
[In General Formulas (a) and (b), X represents a divalent aliphatic group having 2 to 18 carbon atoms or a divalent aromatic group having 6 to 18 carbon atoms, and Z represents a divalent carbon number of 2 Represents an aliphatic group of ~ 8. ]   The number average molecular weight of the said polycondensed ester compound is 500-2000, The cellulose acylate film of Claim 9 or 10.   The cellulose acylate film according to any one of claims 9 to 11, wherein a terminal of the polycondensed ester compound is sealed.   Furthermore, the cellulose acylate film of any one of Claims 1-12 containing at least 1 sort (s) of the carbohydrate compound which consists of a monosaccharide or a 2-10 monosaccharide unit as a plasticizer.   The cellulose acylate film according to claim 13, wherein the carbohydrate compound has an alkyl group, an aryl group, or an acyl group.   The cellulose acylate film according to claim 13 or 14, wherein the carbohydrate compound has an acyl group.   A polarizing plate having at least the cellulose acylate film according to claim 1 and a polarizer.   A liquid crystal display device comprising at least the polarizing plate according to claim 16 and a liquid crystal cell.

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