KR101678695B1 - Cellulose ester film, polarizer and liquid crystal display device - Google Patents

Abstract

(assignment)
Provided is a cellulose ester film having a small surface defect, a small change in optical performance over time, and a small change in time-lapse performance of a polarizing plate when attached as a protective film to a polarizing plate.
(Solution)
(I), an aromatic sugar ester compound represented by the formula (I), an aromatic sugar ester compound represented by the formula (II) and an aliphatic sugar ester compound represented by the formula (III) A cellulose ester film having an average ester substitution degree of an aromatic sugar ester compound and an aromatic sugar ester compound represented by the general formula (II) of less than 94%.
(I) (HO) mG- ( LR 1) n; (II) (HO) pG- ( LR 1) q; (III) (HO) t-G '- (L'-R ² ) r;
(Wherein G and G 'each represent a monosaccharide residue or a 2-sugar residue, R ¹ represents an aliphatic group or an aromatic group, at least one aromatic group, R ² represents an aliphatic group, L and L' represent a divalent linking group, Q is an integer of 1 or more, r is an integer of 3 or more, provided that m + n? 4; p + q? 4; m>

Description

TECHNICAL FIELD [0001] The present invention relates to a cellulose ester film, a polarizing plate, and a liquid crystal display device using the cellulose ester film,

The present invention relates to a cellulose ester film, a polarizing plate, and a liquid crystal display.

Polymer films represented by cellulose ester, polyester, polycarbonate, cycloolefin polymer, vinyl polymer, and polyimide are used for the silver halide photographic photosensitive material, the retardation film, the polarizing plate and the image display device. From these polymers, a film superior in planarity and uniformity can be produced, and is widely employed as a film for optical use. For example, a cellulose ester film having an appropriate moisture permeability can be directly bonded on-line with a polarizer made of the most common polyvinyl alcohol (PVA) / iodine. For this reason, cellulose esters, particularly cellulose acetate, have been widely adopted as protective films for polarizing plates.

When a cellulose ester film is used in a liquid crystal display device, it is necessary to make the film hydrophobic in order to protect polarizers (polarizer durability) due to environmental changes. Additives are usually used for hydrophobing. However, the solution film production method widely used as a method for producing a cellulose ester film includes a drying step for volatilizing the solvent in a short time. However, the additive for hydrophobicization is volatilized in the drying process and adhered to the manufacturing machine, and then adhered to the film as a contaminant as a result of cooling again, which has been a problem as a cause of surface defects.

A method of increasing the molecular weight of additives for the purpose of suppressing volatilization has recently been known. However, there is a problem that an additive having a large molecular weight bleeds out from the film, and when a plasticizer of the sugar induction system is used as an additive, .

On the other hand, Patent Document 1 discloses that when a part of OH groups of a derivative of a sugar of a sucrose skeleton is remained and at least two or more kinds of substituents having different numbers of OH groups are combined, There is disclosed a method for producing a film of a cellulose ester film which does not cause an outage. In addition, in this document, it is possible to effectively compensate for a substantial deviation in the acyl substitution degree of the cellulose ester molecule by using a mixture of a low-substituted and a high-substituted sugar ester. Thus, the resulting film has high durability after saponification, And the durability of the polarizing plate is improved. However, no reference has been made to the combination of an aromatic sugar ester and an aliphatic sugar ester in this document. In the examples of Patent Document 1, a mixture of three substituents having different degree of substitution of sucrose benzoate, which is an aromatic sugar ester having an aromatic group as a substituent in a side chain, is mainly used as a sugar ester plasticizer . In addition, other examples are also disclosed in this document. However, all of them are combinations in which only aromatic sugar esters are used in combination, or aliphatic sugar esters are used in combination.

Further, in Patent Document 2, by using a low substitution product in which a part of the OH groups of a compound which is a derivative of a sucrose skeleton sugar remains, it is possible to improve light leakage and contrast by reducing the haze and improving the coating unevenness of the hard coat layer . In this document, an aliphatic sugar ester having an aliphatic group as a substituent in the side chain is used as a sugar ester plasticizer in addition to an aromatic sugar ester. However, examples in which both are mixed are not disclosed, none.

On the other hand, in a liquid crystal display device, it is a well-known technology to use an optical compensation film for enlarging a viewing angle, improving image coloring, and improving contrast. An optical compensation film capable of controlling optical characteristics (for example, Re value and Rth value) to a desired value is required particularly in the most widely used VA (Vertically Aligned) mode (vertical alignment mode) and TN mode.

Adjustment of optical characteristics suitable for the VA mode requires stretching treatment, and measures against surface defects due to process contamination at the time of production are strongly demanded.

International Publication No. WO2009 / 011228 International Publication No. WO2009 / 031464

On the contrary, as a result of using the sugar ester plasticizer described in these documents, the inventors of the present invention have not yet been able to satisfactorily satisfy the operation problems of the production equipment due to the volatilization of the additive and the occurrence of the plane defects of the film. Further, the inventors of the present invention have examined the Rth of a film and the orthogonal transmittance in the form of a polarizing plate when the time elapsed under a humid environment is examined. As a result, it has been found that these performances can not be satisfied.

An object of the present invention is to provide a cellulose ester film having a small surface defect, a small change in optical performance over time, and a small change in time-lapse performance of a polarizing plate when the polarizing plate is mounted as a protective film on a polarizing plate.

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that the use of aromatic sugar esters tends to cause variations in optical characteristics over time during use. Thus, as a result of mixing aliphatic sugar esters with a mixture of two or more kinds of aromatic sugar esters having different degree of substitution, surprisingly, it has been found that the change in optical performance with time elapsed when an aromatic sugar ester is used is suppressed. Further, it has been found that all of the above-described problems are satisfied at the same time by such a configuration.

That is, as a result of intensive studies, the present inventors have found that the above problems are solved by the present invention having the following constitution.

[1] A process for producing a cellulose ester, which comprises mixing a cellulose ester, an aromatic sugar ester compound represented by the following formula (I), an aromatic sugar ester compound represented by the following formula (II) and an aliphatic sugar ester compound represented by the following formula , And the average ester substitution degree of the aromatic sugar ester compound represented by the general formula (I) and the aromatic sugar ester compound represented by the general formula (II) is less than 94%.

(I) (HO) mG- (LR ¹ ) n

(II) (HO) pG- ( LR 1) q

(III) (HO) t-G '- (L'-R ² ) r

(In the general formulas (I) to (III), G and G 'each independently represent monosaccharide residue or 2 sugar residue.) Each R ¹ independently represents an aliphatic group or aromatic group, and at least one represents an aromatic group. R ² represents an aliphatic, each independently. L and L 'each independently represents a divalent linking group. m represents an integer of 1 or more, p represents an integer of 0 or more, n and q are each independently an integer of 1 or more M + n? 4, p + q? 4, m > p, n < q, and m + n And p + q are the same as the number of hydroxyl groups in the case where G is not a residue but a non-substituted saccharide of a cyclic acetal structure having the same skeleton, and r + t is the same skeleton as G ' Unsubstituted saccharides of the cyclic acetal structure of Is the same as the number of hydroxyl groups in the case of &lt; RTI ID = 0.0 &gt;

[2] The cellulose ester film according to [1], wherein R ² in the general formula (III) represents two or more aliphatic groups.

[3] The cellulose ester film according to [1] or [2], wherein G 'in the general formula (III) represents a residue of 2 sugars.

[4] A process for producing an aromatic sugar ester compound represented by the general formula (I) wherein the G in the general formula (I) and the general formula (II) is a sucrose skeleton and the aromatic sugar ester compound represented by the general formula (I) The cellulose ester film according to any one of [1] to [3], wherein the cellulose ester film has an average ester substitution degree of 5 to 7.5.

[5] The process for producing the aromatic dihydroxy compound according to any one of [1] to [5], wherein the addition amount of the aromatic sugar ester having q of 8 in the general formula (II) Is less than 20% by mass relative to the cellulose ester film.

[6] The L in the general formula (I) and the L in the general formula (II) and L 'in the general formula (III) are each independently a single bond, -O-, -CO-, -NR ¹¹ - (Wherein R &lt; ¹¹ &gt; represents a monovalent substituent). [5] The cellulose ester film according to any one of [1] to [5] above,

[7] The compound according to any one of [1] to [6], wherein R ¹ in the general formula (I) and R ² in the general formula (III) each independently represents an acyl group. And the cellulose ester film according to any one of claims 1 to 5.

[8] The cellulose ester film according to any one of [1] to [7], wherein R ¹ in the general formula (I) and the general formula (II) represents a benzoyl group.

[9] The cellulose ester film according to any one of [1] to [8], wherein each of R ² in the general formula (III) independently represents a non-cyclic aliphatic group.

[10] The cellulose ester film according to any one of [1] to [9], wherein at least one of R ² in the general formula (III) represents a branched aliphatic group.

[11] The cellulose ester film according to any one of [1] to [10], wherein R ² in the general formula (III) comprises only an acetyl group and an isobutyryl group.

[12] A polarizer comprising: a polarizer; and a protective film disposed on both sides of the polarizer,

Wherein at least one of the protective films is a cellulose ester film according to any one of [1] to [11].

[13] A liquid crystal display device comprising a liquid crystal cell and a polarizing plate disposed on both sides of the liquid crystal cell, wherein at least one of the polarizing plates is a polarizing plate described in [12].

According to the present invention, it is possible to provide a cellulose ester film having a small surface defect, a small change in optical performance over time, and a small change in time-lapse performance of a polarizing plate when the polarizing plate is mounted as a protective film on a polarizing plate. In addition, it is possible to provide a polarizing plate having a small change in performance over time using the cellulose ester film. Further, it is possible to provide a liquid crystal display device having a good display quality using the film or the polarizing plate.

Hereinafter, the contents of the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, &quot; &quot; is used to mean that the numerical values described before and after the lower limit and the upper limit are included.

[Cellulose ester film]

The cellulose ester film of the present invention (hereinafter also referred to as the film of the present invention) comprises a cellulose ester, an aromatic sugar ester compound represented by the following formula (I), an aromatic sugar ester compound represented by the following formula (II) The aromatic ester compound represented by the general formula (I) and the aromatic ester compound represented by the general formula (II) have an average ester substitution degree of less than 94%, which contains an aliphatic sugar ester compound represented by the general formula (III) .

(I) (HO) mG- (LR ¹ ) n

(II) (HO) pG- ( LR 1) q

(III) (HO) t-G '- (L'-R ² ) r

(In the general formulas (I) to (III), G and G 'each independently represent monosaccharide residue or 2 sugar residue.) Each R ¹ independently represents an aliphatic group or aromatic group, and at least one represents an aromatic group. R ² represents an aliphatic, each independently. L and L 'each independently represents a divalent linking group. m represents an integer of 1 or more, p represents an integer of 0 or more, n and q are each independently an integer of 1 or more M + n? 4, p + q? 4, m > p, n < q, and m + n And p + q are the same as the number of hydroxyl groups in the case where G is not a residue but a non-substituted saccharide of a cyclic acetal structure having the same skeleton, and r + t is the same skeleton as G ' Unsubstituted saccharides of the cyclic acetal structure of Is the same as the number of hydroxyl groups in the case of &lt; RTI ID = 0.0 &gt;

Hereinafter, the cellulose ester film of the present invention will be described.

&Lt; Diester compound &

The film of the present invention comprises an aromatic sugar ester compound represented by the following formula (I), an aromatic sugar ester compound represented by the following formula (II) and an aliphatic sugar ester compound represented by the following formula (III) The average ester substitution degree of the aromatic sugar ester compound represented by the general formula (I) and the aromatic sugar ester compound represented by the general formula (II) is less than 94%.

(I) (HO) mG- (LR ¹ ) n

(II) (HO) pG- ( LR 1) q

(III) (HO) t-G '- (L'-R ² ) r

(In the general formulas (I) to (III), G and G 'each independently represent monosaccharide residue or 2 sugar residue.) Each R ¹ independently represents an aliphatic group or aromatic group, and at least one represents an aromatic group. R ² each independently represents an aliphatic. L and L 'each independently represents a divalent linking group. p represents an integer of 0 or more, m represents an integer of 1 or more, p represents an integer of 0 or more, n and q is independently an integer of 1 or more, r is an integer of 3 or more, and t is an integer of 0 or more, with m + n? 4, p + q? 4, m & q and m + n and p + q are the same as the number of hydroxyl groups in the case where G is not a residue but a saccharide of an unsubstituted acetal structure of the same skeleton and r + G 'is not a residue but a ring of the same skeleton It is equal to the number of hydroxyl groups in the case of assuming that the unsubstituted saccharide acetal structure)

Specifically, the present invention is characterized in that a mixture of a plurality of aromatic sugar ester compounds having different degree of ester substitution and an aliphatic sugar ester compound are mixed so as to satisfy the above-mentioned conditions. By adding the above sugar ester compound mixture to a cellulose ester film, it is possible to obtain a cellulose ester film having a small surface defect, a small change in optical performance over time, and a small change in time-lapse performance of the polarizing plate when the polarizing plate is attached as a protective film to a polarizing plate .

Hereinafter, a preferable range common to each sugar ester compound used in the sugar ester compound mixture and a preferable range specific to each sugar ester compound satisfying each of the general formulas (I) to (III) will be described.

(Properties common to each ester compound)

Each sugar ester compound used in the sugar ester compound mixture has a skeleton of monosaccharide residue or 2 sugar residue. That is, in the general formulas (I) to (III), G and G 'each independently represent monosaccharide residue or 2 sugar residue.

The sugar ester compound means a compound in which at least one substitutable group (for example, a hydroxyl group or a carboxyl group) in the sugar skeleton structure constituting the compound and at least one substituent group are ester-bonded. That is, the sugar ester compound referred to herein also includes a sugar-derived derivative of a wide variety, including, for example, a compound containing a sugar residue such as gluconic acid as a structure. That is, the sugar ester compound includes an ester form of glucose and a carboxylic acid, and an ester form of gluconic acid and an alcohol.

The sugar ester compound represented by the above general formulas (I) to (III) which can be used in the present invention is preferably a compound having a furanose structure or a pyranose structure. (I) to (III), the condition that m + n? 4, p + q? 4, and r is 3 or more is satisfied when the compound has a furanose structure or a pyranose structure as a sugar skeleton .

When m + n and p + q have a furanose structure or a pyranose structure as a sugar skeleton, it is preferable that m + n and p + q each represent an unsubstituted saccharide of a cyclic acetal structure of the same skeleton, And the condition that r + t is equal to the number of hydroxyl groups in the case where G 'is not a residue but is assumed to be an unsubstituted saccharide of a cyclic acetal structure of the same skeleton may be satisfied.

The upper limit value of m + n, p + q and r + t may be a value determined according to the kind of G or G '. If G or G' is a monosaccharide residue, .

The sugar ester compound represented by the above general formulas (I) to (III) is a compound represented by the general formula (I) or (II) in the compound (A) wherein G or G 'having one furanose structure or pyranose structure is a monosaccharide residue, Or an esterified compound in which all or a part of the OH groups in the compound (B) in which G or G 'is a divalent sugar residue, in which at least one of two structures of the structure or pyranose structure is bonded is esterified.

It is to be noted that the sugar ester compound mixture used in the present invention which satisfies m > p and n < q in the general formulas (I) and (II) In the sugar ester compounds, all of the OH groups are not esterified. Use of a plurality of aromatic sugar ester compounds having different degrees of ester substitution in this way lowers the vaporization property in the production process and makes it difficult to bleed out from the cellulose ester film after the film production.

Examples of the compound (A) include, but are not limited to, glucose, galactose, mannose, fructose, xylose, and arabinose.

Examples of the compound (B) include lactose, sucrose, nisutose, 1F-fructosylnitose, stachyose, maltitol, lactitol, lactose, cellobiose, maltose, celotriose, maltotriose, Pinose or kestos. In addition, examples include, but are not limited to, gentiobiose, gentiootriose, gentiotetraose, xylotriose, and galactosyl sucrose.

Among these compounds (A) and (B), a compound having both a furanose structure and a pyranose structure is particularly preferable. For example, sucrose, kestose, nastose, 1F-fructosylnitose, stachyose and the like are preferable, and sucrose is more preferable. Also, in the compound (B), a compound in which at least one of the furanose structure or the pyranose structure is bonded is also one of the preferred embodiments.

The substituent used for esterifying all or part of the OH groups in the compound (A) and the compound (B) is not particularly limited. Among them, it is preferable to use a monocarboxylic acid. That is, it is preferable that R ¹ in the general formula (I) and the general formula (II) and R ² in the general formula (III) each independently represent an acyl group.

The monocarboxylic acid is not particularly limited and known aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids can be used. The carboxylic acid to be used may be a single kind or a mixture of two or more types. When there are a plurality of R ¹ or R ² , they may be the same or different.

The L in the general formula (I) and the general formula (II) and the L 'in the general formula (III) are each independently a single bond, -O-, -CO-, -NR ¹¹ - And R &lt; ¹¹ &gt; represents a monovalent substituent), and when there are a plurality of L &lt; ^{1 &gt;} or L &apos;, they may be the same or different. Among them, it is preferable that L ¹ or L 'represents -O- from the viewpoint that R ¹ and R ² can be easily substituted with an acyl group.

(A mixture of aromatic sugar ester compounds represented by the general formulas (I) and (II)

Next, preferred embodiments of the aromatic sugar ester compounds represented by the above general formulas (I) and (II) will be described.

In the general formulas (I) and (II), each R ¹ independently represents an aliphatic group or an aromatic group, and at least one of them represents an aromatic group. Among them, it is preferable that each of R &lt; ¹ &gt; independently represents an aromatic group, and more preferably all of the same aromatic group.

The aromatic ester compound represented by the general formula (I) and the aromatic ester compound represented by the general formula (II) have an average ester substitution degree of less than 94%. When the average ester substitution degree of the mixture of two or more kinds of aromatic sugar ester compounds is less than 94%, the haze of the obtained cellulose ester film can be remarkably reduced, and the optical film can be favorably used as a polarizing plate or a liquid crystal display device .

When the aromatic ester compound represented by the general formula (I) and the aromatic ester compound represented by the general formula (II) have an average ester substitution degree of 62% or more and less than 94%, the orthorhombic transmittance From the viewpoint of making it possible to reduce a time-dependent change of the time.

It is preferable that the G in the general formula (I) and the general formula (II) is a sucrose skeleton and the average of the aromatic sugar ester compound represented by the general formula (I) and the aromatic sugar ester compound represented by the general formula (II) The degree of ester substitution is preferably from 5 to 7.5, more preferably from 5.5 to 7.0, from the viewpoint of reducing the time-course change of the orthogonal transmittance under a humid environment when the polarizing plate is mounted on the polarizing plate.

In the general formulas (I) and (II), m represents an integer of 1 or more, p represents an integer of 0 or more, n and q each independently represent an integer of 1 or more, m> < q.

In the present invention, when the G is a residue per 2, the amount of the aromatic sugar ester having q of 8 in the general formula (II) Is preferably less than 20% by mass based on the total amount of the aromatic sugar ester compound represented by the formula (1), from the viewpoint of significantly reducing the haze of the resulting cellulose ester film. When the G is a residue per 2, the content of the aromatic sugar ester compound having no hydroxyl group as a substituent is preferably 20% by mass or less, more preferably 15% by mass or less based on the content of the total aromatic sugar ester By mass, particularly preferably 10% by mass or less, particularly preferably 5% by mass or less.

On the other hand, in the present invention, when the aromatic sugar ester compound represented by the general formula (I) and the aromatic sugar ester compound represented by the general formula (II) are residues of 2 glycosides, it is preferable that n is 3 or more, 5 or more. That is, in the present invention, the aromatic sugar ester compound contained in at least the aromatic sugar ester compound mixture is preferably at least three substituents, more preferably at least five substituents.

When the aromatic sugar ester compound is a disaccharide, the content of the esterified substituent is preferably 3 to 5 to 3 to 5 substituents in the aromatic sugar ester compound in an amount of 10 to 70%, more preferably 20 to 50% desirable. The content of the substituent is preferably 20 to 85%, more preferably 20 to 75%, with respect to the total aromatic ester compound.

Examples of preferred aromatic monocarboxylic acids to be used when substituted by R ¹ include aromatic monocarboxylic acids having an alkyl or alkoxy group introduced into a benzene ring of benzoic acid such as benzoic acid or toluic acid; Cinnamic acid; Aromatic monocarboxylic acids having two or more benzene rings such as benzylic acid, biphenylcarboxylic acid, naphthalenecarboxylic acid and tetralinecarboxylic acid; And derivatives thereof. Specific examples thereof include xylyl acid, hemellitic acid, mesitylene acid, prenyl acid,? -Isodalic acid, fulleric acid, mesitylic acid,? -Isoduryl acid, anthraquinone, m-anisic acid, p-anisic acid, creosotic acid, o-homosalicylic acid, m-homosalicylic acid, p-homoacetic acid, But are not limited to, salicylic acid, o-pyrocatecholic acid,? -Resoric acid, vanillic acid, isobanilic acid, veratric acid, o-veratric acid, gallic acid, aspartic acid, mandelic acid, Benzoic acid, phthalic acid, o-homo veratric acid, phthalic acid, and p-cumaric acid. Particularly, benzoic acid is preferable. That is, it is preferable that R ¹ in the general formulas (I) and (II) represents a benzoyl group.

The aromatic sugar ester compound having a plurality of different degrees of ester substitution is not particularly limited and a known method can be used. The mixing timing of the aromatic sugar ester compound having a plurality of different degrees of ester substitution may be, for example, before or after the addition to the cellulose ester dope when a solution film production method is adopted, and a plurality of sugar ester compounds may be added to the cellulose ester dope Or may be added separately.

(Preferred embodiment of aliphatic sugar ester compound)

Next, preferred embodiments of the aliphatic sugar ester compound represented by the general formula (III) will be described. In the general formula (III), each R ² independently represents an aliphatic group.

Preferred aliphatic monocarboxylic acids to be used when substituted by R ² include acetic, propionic, butyric, isobutyric, valeric, capronic, enantic, caprylic, feraric, capric, 2- -Hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, Saturated fatty acids such as acid, cellulosic acid, heptanoic acid, montanic acid, myristic acid, and lactic acid; Unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid and octenoic acid.

Examples of preferred alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof.

It is preferable that each of R ² independently represents a non-cyclic aliphatic group, and it is preferable that all R ² represent a non-cyclic aliphatic group.

It is preferable that R ² represents two or more aliphatic groups.

Among the aliphatic monocarboxylic acids, the aliphatic sugar ester compound represented by the general formula (III) is preferably substituted with at least acetic acid. That is, it is preferable that at least one of R ² in the general formula (III) represents an acetyl group.

It is particularly preferable that at least one of R ² represents a branched aliphatic group, and when R ² represents two or more aliphatic groups, it is particularly preferable that only one kind represents a branched aliphatic group. Among them, the aliphatic sugar ester compound represented by the general formula (III) is preferably substituted with isobutyric acid in addition to acetic acid. That is, it is preferable that R ² in the general formula (III) includes an acetyl group and an isobutyryl group, and it is preferable that the R ² includes an acetyl group and an isobutyryl group from the viewpoint of optical performance over time.

It is preferable that G 'in the general formula (III) represents a residue of 2 sugar from the viewpoints of improving the surface defect of the obtained cellulose ester film and improving the polarizer durability.

In the case where R ² in the general formula (III) is composed of only acetyl group and isobutyryl group, for example, when G 'is a residue of 2 per group, the ratio is acetyl group / isobutyryl group = 4, more preferably 1/7 to 3/5, and particularly preferably 2/6.

A process for producing an aliphatic mono-carboxylic acid-substituted aliphatic sugar ester compound is described in, for example, JP-A-8-245678.

An example of a preparation example of the esterified compound is as follows.

Acetic anhydride (200 ml) was added dropwise to a solution of glucose (29.8 g, 166 mmol) in which pyridine (100 ml) was added and reacted for 24 hours. The solution was then concentrated with Evaporate and added to ice water. After standing for 1 hour, the mixture was filtered through a glass filter, and the solid and water were separated. The solid on the glass filter was dissolved in chloroform and separated by cold water until neutral. The organic layer was separated and dried over anhydrous sodium sulfate. The anhydrous sodium sulfate was removed by filtration, and then chloroform was removed by evaporation and further dried under reduced pressure to obtain glycose pentaacetate (58.8 g, 150 mmol, 90.9%). Further, the above-mentioned monocarboxylic acid may be used in place of acetic anhydride.

Specific examples of sugar ester compounds represented by the general formulas (I) to (III) that can be used in the present invention are shown below, but the present invention is not limited thereto. In the following specific examples, the ester substitution degree of each sugar ester compound is not described, but any sugar ester compound having any degree of ester substitution may be used as long as it does not contradict the object of the present invention. have. In particular, any of the aromatic sugar ester compounds represented by the general formulas (I) and (II) may be selected to satisfy the requirements of the present invention.

[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the following structural formulas, Rs each independently represent an arbitrary substituent, and a plurality of Rs may be the same or different.

[Chemical Formula 6]

(7)

[Chemical Formula 8]

(Mixing of an aromatic sugar ester compound and an aliphatic sugar ester compound)

By adding a plurality of aromatic sugar ester compounds having different degrees of ester substitution that satisfy the above conditions and the aliphatic sugar ester compound to the cellulose ester film to obtain a mixture of the aromatic sugar ester compound and the aromatic sugar ester compound, The optical performance durability and polarizer durability of the film under a humid environment can be further improved. It is also possible to improve the durability of the optical performance of the film and the durability of the polarizer naturally for known phosphate ester plasticizers such as so-called TPP / BDP. Further, when laminated with the hard coat layer, a film having excellent adhesion and excellent pencil hardness can be obtained.

The cellulose ester film of the present invention preferably contains 1 to 30 mass%, preferably 5 to 20 mass%, of the aromatic sugar ester compound represented by the above general formulas (I) and (II) relative to the cellulose ester in total , And particularly preferably from 5 to 15 mass%.

The cellulose ester film of the present invention preferably contains 1 to 30 mass%, more preferably 1 to 10 mass%, and most preferably 1 to 10 mass% of the aliphatic sugar ester compound represented by the general formula (III) By mass to 5% by mass.

The mixing ratio of the aromatic sugar ester compound represented by the general formula (I) or (II) and the aliphatic sugar ester compound represented by the general formula (III) is not particularly limited. Among them, the addition amount of the aromatic sugar ester compound / the addition amount of the aliphatic ester compound (mass ratio) is preferably more than 1, more preferably 2 to 10, and particularly preferably 3 to 5.

The cellulose ester film of the present invention preferably contains 1 to 30 mass%, more preferably 5 to 30 mass%, of the total of the sugar ester compounds represented by the above general formulas (I) to (III) relative to the cellulose ester , Particularly preferably from 5 to 20 mass%, particularly preferably from 5 to 15 mass%. Within this range, there is no bleeding-out or the like, which is preferable.

When a polycondensation ester plasticizer to be described later is used in combination with the sugar ester compound, the addition amount (mass part) of the sugar ester compound to the addition amount (mass part) of the polycondensation ester plasticizer is 2 to 10 times (mass ratio) , And more preferably 3 to 8 times (mass ratio).

When a compound having at least two aromatic rings described below is used in combination with the sugar ester compound, the addition amount (mass part) of the sugar ester compound to the added amount (mass part) of the compound having at least two aromatic rings , Preferably 2 to 10 times (mass ratio), more preferably 3 to 8 times (mass ratio).

The timing of mixing the plurality of aromatic sugar ester compounds and the aliphatic sugar ester compound may be, for example, before or after the addition to the cellulose ester dope when employing the solution film production method, May be separately added.

<Polycondensation ester>

The film of the present invention may contain a polycondensation ester (hereinafter, also referred to as an oligomer plasticizer) unless it is contrary to the object of the present invention.

The polycondensation ester comprises at least one aromatic dicarboxylic acid (dicarboxylic acid having an aromatic ring), at least one aliphatic dicarboxylic acid, at least one aliphatic diol, at least one monocarboxylic acid A mixture containing an acid can be obtained as a raw material.

Preferable examples of the oligomer plasticizer include polycondensation esters and derivatives thereof of a diol component and a dicarboxylic acid component, and oligomers and derivatives of methyl acrylate (MA) (hereinafter sometimes referred to as &quot; MA oligomer plasticizer &quot;) .

The polycondensation ester is a polycondensation ester of a dicarboxylic acid component and a diol component. The dicarboxylic acid component may be composed of only one kind of dicarboxylic acid, or may be a mixture of two or more kinds of dicarboxylic acids. Among them, as the dicarboxylic acid component, it is preferable to use a dicarboxylic acid component containing at least one aromatic dicarboxylic acid and at least one aliphatic dicarboxylic acid. On the other hand, the diol component may be composed of only one kind of diol component, or may be a mixture of two or more kinds of diols. Among them, it is preferable to use, as the diol component, an aliphatic diol having ethylene glycol and / or an average carbon number of more than 2.0 and not more than 3.0.

As the polycondensation ester, the compounds described in [0029] to [0045] of JP-A-2010-079241 can be preferably used.

&Lt; Compound having at least two aromatic rings >

The cellulose ester film of the present invention may contain a compound having at least two aromatic rings in addition to the object of the present invention.

Hereinafter, the compound having at least two aromatic rings will be described.

It is preferable that a compound having at least two aromatic rings exhibits optically positive uniaxiality when the compound is uniformly oriented.

The molecular weight of the compound having at least two aromatic rings is preferably 300 to 1200, more preferably 400 to 1000.

When the cellulose ester film of the present invention is used as an optical compensation film, stretching is effective for controlling optical properties, particularly Re, to a desirable value. The rise of Re needs to increase the refractive index anisotropy in the film plane, and one method is improvement of the main chain orientation of the polymer film by stretching. Further, by using a compound having a large refractive index anisotropy as an additive, it is possible to further increase the refractive index anisotropy of the film. For example, in the case of a compound having two or more aromatic rings, the orientation of the polymer is improved by stretching the polymer main chain by stretching, and the control of the compound with the desired optical properties is facilitated.

Examples of the compound having at least two aromatic rings include triazine compounds described in Japanese Patent Application Laid-Open No. 2003-344655, rod-shaped compounds disclosed in Japanese Patent Application Laid-Open No. 2002-363343, Japanese Laid-Open Patent Publication No. 2005-134884, And liquid crystal compounds described in JP-A-2007-119737. More preferably, the triazine compound or the rod-shaped compound is used.

Two or more compounds having at least two aromatic rings may be used in combination.

<Cellulose Ester>

In the cellulose ester film of the present invention, examples of the cellulose ester include a cellulose ester compound and a compound having an ester-substituted cellulose skeleton obtained by biologically or chemically introducing a functional group using cellulose as a raw material.

The cellulose ester is an ester of cellulose and an acid. The acid constituting the ester is preferably an organic acid, more preferably a carboxylic acid, more preferably a fatty acid having 2 to 22 carbon atoms, and most preferably a cellulose ester as a lower fatty acid having 2 to 4 carbon atoms .

Examples of the cellulose of the cellulose ester raw material used in the present invention include cotton linters, wood pulp (hardwood pulp, softwood pulp), and cellulose esters obtained from any raw cellulose may be used. A detailed description of these raw materials of cellulose can be found in, for example, &quot; Plastic material lecture (17) Fiber sublimation resin &quot; (Maruzawa, Udagawa, To 8 pages) can be used, and the cellulose ester film of the present invention is not particularly limited.

Next, the cellulose ester which is made from the above-described cellulose as a raw material and which is preferable in the present invention will be described.

The cellulose ester used in the present invention is acylated with a hydroxyl group of cellulose, and the substituent can be used from an acetyl group having 2 carbon atoms to an acetyl group having 22 carbon atoms. The degree of substitution of the cellulose with respect to the hydroxyl group in the cellulose ester in the present invention is not particularly limited, but the degree of substitution of acetic acid and / or fatty acid having 3 to 22 carbon atoms substituted in the hydroxyl group of cellulose is measured, The degree of substitution can be obtained. The measurement can be carried out in accordance with ASTM D-817-91.

As described above, the degree of substitution of the cellulose with respect to the hydroxyl group is not particularly limited, but the degree of substitution of the cellulose with respect to the hydroxyl group of the cellulose is preferably 2.00 to 2.95.

The acyl group having 2 to 22 carbon atoms in the acetic acid and / or the fatty acid having 3 to 22 carbon atoms which is substituted for the hydroxyl group of the cellulose may be an aliphatic group or an aryl group and is not particularly limited and may be a single, do. They may be, for example, alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, or aromatic alkylcarbonyl esters of cellulose and the like, each having an additional substituted group. Preferred examples of these acyl groups include acetyl, propionyl, butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, Nonyl, t-butanoyl, cyclohexanecarbonyl, oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl and the like. Of these, acetyl, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzoyl, naphthylcarbonyl and cinnamoyl are preferable, and acetyl, propionyl and butanoyl desirable. The most preferred group is acetyl.

In the case where at least two kinds of acetyl groups / propionyl groups / butanoyl groups are substantially contained among the acyl substituents substituted for the hydroxyl group of the cellulose, the total degree of substitution is preferably from 2.50 to 2.95, Is 2.60 to 2.95, and more preferably 2.65 to 2.95.

When the acyl substituent of the cellulose ester is composed only of an acetyl group, the total degree of substitution is preferably 2.00 to 2.95. Further, the degree of substitution is preferably 2.40 to 2.95, more preferably 2.85 to 2.95.

The degree of polymerization of the cellulose ester preferably used in the present invention is 180 to 700 in viscosity average degree of polymerization, more preferably 180 to 550, more preferably 180 to 400, and particularly preferably 180 to 350 in cellulose acetate . If the degree of polymerization is not more than the upper limit, the viscosity of the dope solution of the cellulose ester is not excessively increased, which is preferable because it is easy to produce a flexible film. If the degree of polymerization is not lower than the lower limit, it is preferable because no problem such as lowering of the strength of the produced film occurs. The viscosity average degree of polymerization can be measured by the intrinsic viscosity method such as Uda et al. (Udakazuo, Hideo Saito, &quot; Textile Journal &quot;, Vol. 18, No. 1, pp. 105-120 (1962)). This method is described in detail in Japanese Patent Application Laid-Open No. 9-95538.

The molecular weight distribution of the cellulose ester preferably used in the present invention is evaluated by gel permeation chromatography, and its polydispersity index Mw / Mn (Mw is the mass average molecular weight, Mn is the number average molecular weight) is small, Is narrow. The specific Mw / Mn value is preferably 1.0 to 4.0, more preferably 2.0 to 4.0, and most preferably 2.3 to 3.4.

&Lt; Process for producing cellulose ester film >

The cellulose ester film of the present invention can be produced by a solvent casting method. In the solvent casting method, a film is prepared using a solution (dope) in which cellulose ester is dissolved in an organic solvent.

The organic solvent preferably includes a solvent selected from ethers having 3 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, esters having 3 to 12 carbon atoms, and halogenated hydrocarbons having 1 to 6 carbon atoms.

The ether, ketone and ester may have a cyclic structure. Compounds having two or more functional groups (i.e., -O-, -CO- and -COO-) of an ether, a ketone and an ester can also be used as the organic solvent. The organic solvent may have another functional group such as an alcoholic hydroxyl group. In the case of an organic solvent having two or more kinds of functional groups, the number of carbon atoms is preferably within the above-mentioned preferable number of carbon atoms of a solvent having a certain functional group.

Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, .

Examples of the ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexanone.

Examples of the esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate.

Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

The number of carbon atoms of the halogenated hydrocarbon is preferably 1 or 2, and most preferably 1. The halogen of the halogenated hydrocarbon is preferably chlorine. The ratio of the hydrogen atoms of the halogenated hydrocarbons substituted with halogen is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, still more preferably 35 to 65 mol%, and even more preferably 40 to 60 mol% Is most preferable. Methylene chloride is a representative halogenated hydrocarbon.

Two or more kinds of organic solvents may be mixed and used.

The cellulose ester solution can be prepared by a general method comprising treating at a temperature of 0 ° C or higher (room temperature or high temperature). The solution can be prepared by using a method and apparatus for preparing dope in an ordinary solvent casting method. Further, in the case of a general method, it is preferable to use a halogenated hydrocarbon (particularly, methylene chloride) as the organic solvent.

The amount of the cellulose ester is adjusted so as to be contained in the resulting solution by 10 to 40 mass%. The amount of the cellulose ester is more preferably 10 to 30 mass%. Any of the additives described below may be added to the organic solvent (main solvent).

The solution can be prepared by stirring the cellulose ester and the organic solvent at room temperature (0 to 40 ° C). The high concentration solution may be stirred under pressure and heating conditions. Concretely, the cellulose acetate and the organic solvent are put in a pressure vessel and sealed, and the mixture is heated while being heated under pressure at a temperature not lower than the boiling point of the solvent at room temperature and the solvent is not boiled.

The heating temperature is usually 40 占 폚 or higher, preferably 60 to 200 占 폚, and more preferably 80 to 110 占 폚.

Each component may be preliminarily mixed and then placed in a container. Further, it may be added sequentially to the container. The container needs to be configured to be able to stir. An inert gas such as nitrogen gas may be injected to pressurize the container. Further, an increase in the vapor pressure of the solvent by heating may be used. Alternatively, after sealing the container, each component may be added under pressure.

In the case of heating, it is preferable to heat from the outside of the container. For example, a jacket type heating apparatus can be used. It is also possible to heat the entire container by installing a plate heater on the outside of the container and circulating the liquid through the pipe.

It is preferable to form stirring vanes inside the container and stir using this. It is preferable that the agitating blade has a length reaching near the wall of the container. At the end of the stirring blade, it is preferable to form a scratch blade in order to renew the liquid film on the wall of the container.

Instrumentation such as pressure gauge, thermometer, etc. may be installed in the container. Each component is dissolved in a solvent in a container. The prepared dope is taken out of the container after cooling, or taken out, and then cooled using a heat exchanger or the like.

A cellulose ester film is prepared from the prepared cellulose ester solution (dope) by a solvent casting method. It is preferable to add the retardation increasing agent to the dope.

The dope is flexible on the drum or band and evaporates the solvent to form a film. The concentration of the dope before the softening is preferably adjusted so that the solid content is 18 to 35%. The surface of the drum or band is preferably finished in a mirror-finished state. The dope is preferably flexible on a drum or band with a surface temperature of 10 ° C or lower.

In the present invention, in the case where the dope (cellulose ester solution) is plied into a band, a step of drying in a substantially no-wind for a time of 10 seconds or more and 90 seconds or less, preferably 15 seconds or more and 90 seconds or less, . In the case of pliability on the drum, it is preferable to carry out a step of drying in a substantially no-wind for a time period of 1 second or more and 10 seconds or less, preferably 2 seconds or more and 5 seconds or less in the first half of the pre-

In the present invention, &quot; drying before peeling &quot; refers to drying until the film is peeled off after the dope is coated on the band or drum. The term &quot; first half &quot; refers to a step before half of the total time required from the application of the dope to the peeling. Substantially no wind "means that wind speeds of 0.5 m / s or more are not detected (wind velocity is less than 0.5 m / s) at a distance of 200 mm or less from the band surface or drum surface.

The first half of the drying before peeling is usually about 30 to 300 seconds in the case of the band, and it is dried in a no wind for 10 seconds to 90 seconds, preferably 15 seconds to 90 seconds. In the case of the drum, the drying time is usually about 5 to 30 seconds, and the drying is carried out in a period of from 1 second to 10 seconds, preferably from 2 seconds to 5 seconds, with no wind. The atmospheric temperature is preferably 0 ° C to 180 ° C, more preferably 40 ° C to 150 ° C. The operation of drying with no wind can be carried out at any stage of the entire drying before peeling, and it is preferable to carry out the drying immediately after the peeling. It is difficult for the additive to be uniformly distributed in the film when the drying time is less than 10 seconds (less than 1 second in the case of the drum) in the band mode, and more than 90 seconds ) Is peeled off due to insufficient drying, and the surface of the film deteriorates.

The drying can be carried out by blowing an inert gas for a period of time other than the drying by the no-wind in the drying before the peeling. The air temperature at this time is preferably 0 ° C to 180 ° C, more preferably 40 ° C to 150 ° C.

The drying method in the solvent casting method is described in U.S. Patent Nos. 2336310, 2367603, 2492078, 2492977, 2492978, 2607704, 2739069, 2739070, 690731, JP-B-736892, JP-A-45-4554, JP-A-49-5614, JP-A-60-176834, JP-A-60-203430 and JP-A-62-115035. Drying on bands or drums can be carried out by blowing an inert gas such as air or nitrogen.

The obtained film may be peeled off from a drum or a band, and further dried by a hot air blow with a temperature difference between 100 and 160 DEG C to evaporate the residual solvent. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, it is possible to shorten the time from softening to peeling. In order to carry out this method, it is necessary that the dope gels at the surface temperature of the drum or band at the time of softening.

It is also possible to form two or more layers by using a prepared cellulose ester solution (dope) to form a film. In this case, it is preferable to produce a cellulose ester film by a solvent cast method. The dope is flexible on the drum or band and evaporates the solvent to form a film. The concentration of the dope before the softening is preferably adjusted so that the solid content is in the range of 10 to 40%. The surface of the drum or band is preferably finished in a mirror-finished state.

The preferred width of the cellulose ester film of the present invention is 0.5 to 5 m, more preferably 0.7 to 3 m. The preferable winding length of the film is 300 to 30000 m, more preferably 500 to 10000 m, and still more preferably 1000 to 7000 m.

(Film thickness)

The film thickness of the cellulose ester film of the present invention is preferably 20 m to 180 m, more preferably 30 m to 120 m, and still more preferably 40 m to 100 m. When the film thickness is 20 占 퐉 or more, it is preferable in view of handleability in processing with a polarizing plate or the like and the curl of the polarizing plate. The film thickness irregularity of the cellulose ester film of the present invention is preferably 0 to 2%, more preferably 0 to 1.5%, and particularly preferably 0 to 1% in both the carrying direction and the width direction.

(additive)

To the cellulose ester film, a deterioration inhibitor (for example, an antioxidant, a peroxide dissolution inhibitor, a radical inhibitor, a metal deactivator, an acid capturing agent, or an amine) may be added. With respect to the deterioration inhibitor, there is described in each publication of JP-A-3-199201, 5-194789, 5-271471 and 6-107854. The addition amount of the deterioration inhibitor is preferably from 0.01 to 1% by mass, more preferably from 0.01 to 0.2% by mass, of the solution (dope) to be prepared, from the viewpoints of manifestation of the effect and inhibition of bleed- Is more preferable.

Particularly preferred examples of the deterioration inhibitor include butylated hydroxytoluene (BHT) and tribenzylamine (TBA).

An ultraviolet absorber may be added to the cellulose ester film of the present invention. As the ultraviolet absorber, compounds described in JP-A-2006-282979 (benzophenone, benzotriazole, triazine) are preferably used. Two or more ultraviolet absorbers may be used in combination.

As ultraviolet absorber, benzotriazole is preferable, and specific examples thereof include TINUVIN328, TINUVIN326, TINUVIN329, TINUVIN571, and adecastab LA-31.

The amount of the ultraviolet absorber to be used is preferably not more than 10%, more preferably not more than 3%, and most preferably not less than 2% and not less than 0.05%, based on the mass of the cellulose ester.

(Matte Particle)

The cellulose ester film of the present invention preferably contains fine particles as a matting agent. Examples of the fine particles used in the present invention include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, . It is preferable that the fine particles contain silicon because turbidity is lowered, and silicon dioxide is particularly preferable. The fine particles of silicon dioxide preferably have a primary mean particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more. It is more preferable that the average primary particle diameter is as small as 5 to 16 nm because the haze of the film can be lowered. The apparent specific gravity is preferably 90 to 200 g / l, more preferably 100 to 200 g / l. The larger the apparent specific gravity, the more desirable is the possibility of making a high-concentration dispersion, and the haze and agglomerates are improved. A preferred embodiment is described in detail on pages 35 to 36 of the Inventors Association's public notice (Air No 2001-1745, published on Mar. 15, 2001 by the Invention Society of Japan), and can be preferably used in the cellulose ester film of the present invention have.

(Stretching)

The cellulose ester film of the present invention can adjust the retardation by stretching treatment. Methods of aggressively stretching in the transverse direction (direction perpendicular to the transport direction) are disclosed, for example, in JP-A-62-115035, JP-A-4-152125, JP-A-4-284211 Japanese Laid-Open Patent Publication No. 4-298310, and Japanese Laid-Open Patent Publication No. 11-48271. The stretching of the film is carried out at room temperature or under heating conditions. The heating temperature is preferably within a range of 占 0 占 between the glass transition temperature of the film. If it is stretched at an extremely lower temperature than the glass transition temperature, it tends to be broken and the desired optical properties can not be expressed. In addition, when stretching at a temperature extremely higher than the glass transition temperature, before the molecules oriented by the stretching are thermally fixed, they can be relaxed by the heat at the time of stretching, and the orientation can not be fixed, resulting in poor optical characteristics.

Further, in a stretching zone (for example, a tenter zone), a film is sandwiched and transported to obtain a maximum widening ratio, and then a zone is usually relaxed. This is a zone necessary for reducing the axial misalignment. In the relaxation rate zone after the maximum widening ratio, the time until the tenter zone is allowed to pass is shorter than 1 minute, and the stretching of the film may be uniaxial stretching only in the carrying direction or the width direction, Or biaxial stretching in a sequential manner, it is preferable that the stretching is performed more in the width direction. The stretching in the width direction is preferably 5 to 100%, particularly preferably 5 to 80%. Further, the stretching treatment may be carried out during the film production process, or the original film wound and formed by film production may be stretched. In the case of the former, the stretching may be performed in a state including the residual solvent amount, and the amount of the residual solvent = (residual volatile matter mass / film mass after heat treatment) x 100% is preferably 0.05 to 50%. It is particularly preferable to conduct the stretching at 5 to 80% in the state where the residual solvent amount is 0.05 to 5%.

Further, the cellulose ester film of the present invention may be subjected to biaxial stretching.

The biaxial stretching method is a simultaneous biaxial stretching method and a sequential biaxial stretching method. From the standpoint of continuous production, a sequential biaxial stretching method is preferable. After the dope is made flexible, the film is peeled off from the band or the drum, And then stretched in the longitudinal direction or in the width direction after being stretched in the longitudinal direction.

The process from softening to post-drying may be an air atmosphere or an inert gas atmosphere such as nitrogen gas. The winding machine used in the production of the cellulose ester film of the present invention may be any of those generally used and can be wound by a winding method such as a positive tension method, a constant torque method, a taper tension method, an internal stress constant program tension control method have.

(Surface Treatment of Cellulose Ester Film)

The cellulose ester film is preferably subjected to a surface treatment. Specific examples include a corona discharge treatment, a glow discharge treatment, a flame treatment, an acid treatment, an alkali treatment or an ultraviolet ray irradiation treatment. It is also preferable to form a primer layer as described in JP-A-7-333433.

From the viewpoint of maintaining the flatness of the film, it is preferable that the temperature of the cellulose ester film in these treatments is set to Tg (glass transition temperature) or lower, specifically 150 ° C or lower.

When used as a transparent protective film of a polarizing plate, it is particularly preferable to carry out an acid treatment or an alkali treatment, that is, a saponification treatment to a cellulose ester, from the viewpoint of adhesion with a polarizer.

The surface energy is preferably 55 mN / m or more, more preferably 60 mN / m or more and 75 mN / m or less.

Hereinafter, the alkali saponification treatment will be specifically described.

The alkali saponification treatment of the cellulose ester film is preferably carried out in a cycle in which the surface of the film is immersed in an alkali solution, neutralized with an acidic solution, washed with water and then dried.

Examples of the alkali solution include a potassium hydroxide solution and a sodium hydroxide solution. The hydroxide ion concentration is preferably in the range of 0.1 to 3.0 mol / liter, more preferably in the range of 0.5 to 2.0 mol / liter. The temperature of the alkali solution is preferably in the range of room temperature to 90 deg. C, more preferably in the range of 40 to 70 deg.

The surface energy of a solid can be determined by a contact angle method, a wet heating method, and an adsorption method as described in &quot; Fundamentals and Applications of Wetting &quot; In the case of the cellulose ester film of the present invention, the contact angle method is preferably used.

Specifically, two types of solutions having known surface energies are dripped onto a cellulose ester film, and at an intersection of the surface of the droplet and the surface of the film, an angle formed by the tangent line on the droplet and the film surface, The angle is defined as the contact angle, and the surface energy of the film can be calculated by calculation.

&Lt; Characteristics of cellulose ester film >

The cellulose ester film of the present invention has a small surface defect, a small change in optical performance over time, and a small change in the time-lapse performance of the polarizing plate when the cellulose ester film is mounted as a protective film on the polarizing plate. Here, such a small surface defect is mainly achieved by using the above sugar ester compound mixture as an additive to improve the volatility and bleed-out during film production. In addition, when the sugar ester compound mixture is used as an additive, not only the bleed-out in the drying condition at the time of film production but also the bleed-out in the case where the cellulose ester film obtained after the film production is elapsed under a humid environment can be suppressed .

The characteristics of the cellulose ester film of the present invention will be described below together with other preferable characteristics.

(Retardation of the film)

In the present specification, Re (?) And Rth (?) Indicate retardation in the plane and retardation in the thickness direction at the wavelength?, Respectively. Re (?) Is measured by incident light having a wavelength of? Nm in the normal direction of the film in KOBRA 21ADH or WR (trade name, manufactured by Oji Instruments Co., Ltd.). In the selection of the measurement wavelength? Nm, the wavelength selection filter can be manually replaced, or the measurement value can be converted into a program or the like to be measured.

When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (?) Is calculated by the following method.

Rth (?) Is obtained by setting Re (?) As a tilting axis (rotation axis) of the in-plane slow axis (judged by KOBRA 21ADH or WR) (in the case where there is no slow axis, ) Light from the oblique direction in a direction of 10 degrees from the normal direction to the normal direction with respect to the normal direction of the film, and a total of 6 points are measured. The measured retardation value and the assumed value of the average refractive index and Based on the input film thickness value, KOBRA 21ADH or WR calculates.

In the above case, in the case of a film having a direction in which the retardation value becomes zero at a certain tilt angle with the slow axis in the plane as the rotation axis in the plane from the normal direction, the retardation value at an inclination angle larger than the tilt angle is expressed by the sign KOBRA 21ADH or WR is calculated.

Further, the retardation value is measured from arbitrary oblique directions by using the slow axis as a tilting axis (rotation axis) (in a case where there is no slow axis, an arbitrary direction in the film plane is taken as the rotation axis) Rth may be calculated from the following equations (21) and (22) based on the assumed value and the input film thickness value.

In the formula, Re (&amp;thetas;) represents the retardation value in the inclined direction from the normal direction. ny represents a refractive index in a direction perpendicular to nx and ny, d represents a thickness (nm) of a layer, and n represents a refractive index in a direction orthogonal to nx in the plane. ) to be.

In the case of a film in which a film to be measured can not be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film having no so-called optical axis, Rth (?) Is calculated by the following method.

Rth (?) Is obtained by changing the Re (?) From -50 degrees to +50 degrees in a 10 degree step with respect to the normal direction of the film with the inclined axis (rotation axis) of the in-plane slow axis (determined by KOBRA 21ADH or WR) Light having a wavelength of? Nm is incident from the oblique direction to measure 11 points, and KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed value of the average refractive index, and the inputted film thickness value.

In the above measurement, the value of the average index of refraction can be used in the catalog of polymer handbook (JOHN WILEY & SONS, INC) and various optical films. The value of the average refractive index not known can be measured with an Abbe refractometer. The values of the average refractive index of the main optical film are as follows: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethylmethacrylate (1.49) and polystyrene (1.59). By inputting these assumptions of average refractive index and film thickness, KOBRA 21ADH or WR can calculate nx, ny, nz.

The cellulose ester film of the present invention is used as a protective film of a polarizing plate, and in particular, can be preferably used as a retardation film corresponding to various liquid crystal modes.

When the cellulose ester film of the present invention is used as a retardation film, the preferable optical characteristics of the cellulose ester film are different depending on the liquid crystal mode.

For the VA mode, the Re measured at 590 nm is preferably 20 to 150 nm, more preferably 50 to 130 nm, and even more preferably 70 to 120 nm. The Rth is preferably 100 to 300 nm, more preferably 120 to 280 nm, and even more preferably 150 to 250 nm.

For the TN mode, the Re measured at 590 nm is preferably 0 to 100 nm, more preferably 1 to 50 nm, and even more preferably 2 to 20 nm. The Rth is preferably 20 to 200 nm, more preferably 30 to 150 nm, and even more preferably 40 to 120 nm.

For the TN mode, an optically anisotropic layer may be coated on the cellulose ester film having the above retardation value and used as a retardation film.

(Optical performance time-course change)

The cellulose ester film of the present invention is characterized not only in that Rth is well expressed, but also in the amount of change in Rth before and after elapse of time under a humid environment.

(Haze of film)

The haze of the cellulose ester film of the present invention is preferably 0.01 to 2.0%. , More preferably 0.05 to 1.5%, further preferably 0.1 to 1.0%. The transparency of the film as an optical film is important.

(Composition of cellulose ester film)

The cellulose ester film of the present invention may have a single-layer structure or a plurality of layers, preferably a single-layer structure. Here, the &quot; single-layer structure &quot; film refers to a single cellulose ester film rather than a plurality of film materials. The present invention also includes a case where one cellulose ester film is produced from a plurality of cellulose ester solutions by using a continuous casting method or a continuous casting method.

In this case, a cellulose ester film having a distribution in the thickness direction can be obtained by appropriately adjusting the type and amount of the additive, the molecular weight distribution of the cellulose ester, and the kind of the cellulose ester. Also, those films each having various functional portions such as optically anisotropic portions, antiglare portions, gas barrier portions, and moisture resistant portions are also included in the film.

(Functional layer)

The film of the present invention may be a single layer film or may have a laminated structure of two or more layers. Hereinafter, the polarizing plate of the present invention described below preferably includes a functional layer. Even when the film of the present invention has a functional layer, when the film of the present invention is attached to the polarizing plate of the present invention, .

The functional layer is not particularly limited as long as it is not contradictory to the object of the present invention, and for example, the following functional layer can be mentioned. In particular, when the film of the present invention is used as a base film, it is particularly preferable to directly form the hard coat layer thereon, and it is preferable that the hard coat layer is provided by coating.

Base film / hard coat layer / medium refractive index layer / low refractive index layer

Base film / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index layer

Base film / hard coat layer / low refractive index layer

Base film / hard coat layer / conductive layer / low refractive index layer

Base film / hard coat layer / high refractive index layer (conductive layer) / low refractive index layer

Base film / hard coat layer / antiglare layer / low refractive index layer

It is preferable that the cellulose ester film of the present invention has less uneven application when the hard coat layer is applied.

(Meth) acrylate diesters of alkylene glycols, (meth) acrylate diesters of polyoxyalkylene glycols, polyfunctional (meth) acrylate diesters of polyoxyalkylene glycols, and polyfunctional (Meth) acrylate diesters of alcohols, (meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts, and the like, and epoxy (meth) acrylates, urethane (meth) acrylates, polyester And the like, but the present invention is not limited thereto, and they may be used singly or in combination.

Examples of the photo radical polymerization initiator include azo compounds such as acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides (JP-A 2001-139663 ), 2,3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfoniums, ropin dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes, coumarins And the like, but are not limited thereto.

The coating solution is prepared by dissolving or dispersing the respective components, various solvents which are selected from the viewpoints of a coating step, a step of being easily uniform in the drying step, a step of securing liquid storage stability, Can be used.

The solvent may be a mixture of two or more kinds. In particular, from the viewpoint of drying load, it is preferable that a solvent having a boiling point of 100 ° C or lower at normal pressure room temperature is used as a main component and a small amount of a solvent having a boiling point of 100 ° C or higher is used for adjusting the drying rate. Mixing of the solvent may be performed for fine adjustment of the solubility parameter.

Examples of the solvent having a boiling point of 100 DEG C or less include hydrocarbons such as hexane (boiling point 68.7 DEG C), heptane (98.4 DEG C), cyclohexane (80.7 DEG C) and benzene (80.1 DEG C), dichloromethane Halogenated hydrocarbons such as dichloromethane (61.2 ° C), carbon tetrachloride (76.8 ° C), 1,2-dichloroethane (83.5 ° C) and trichlorethylene (87.2 ° C), diethyl ether (34.6 ° C), diisopropyl ether (57.2 占 폚), ethyl acetate (77.1 占 폚), isopropyl acetate (89.5 占 폚), ethyl acetate (78.3 占 폚), 2-propanol (82.4 占 폚), ketones such as acetone (56.1 占 폚) and 2-butanone (same as methyl ethyl ketone, , And 1-propanol (97.2 ° C), cyano compounds such as acetonitrile (81.6 ° C) and propionitrile (97.4 ° C), carbon disulfide For example octane (125.7 占 폚), toluene (110.6 占 폚), xylene (138 占 폚), tetrachlorethylene (121.2 占 폚), chlorobenzene Methylene-4-pentanone (same as MIBK, 115.9 占 폚), dioxane (101.3 占 폚), dibutyl ether (142.4 占 폚), isobutyl acetate (118 占 폚), cyclohexanone N, N-dimethylformamide (153 DEG C), N, N-dimethylacetamide (166 DEG C), dimethylsulfoxide (189 DEG C), and the like. .

(Retardation film)

The cellulose ester film of the present invention can be used as a retardation film. The term "retardation film" generally refers to an optical material having optical anisotropy which is used in a display device such as a liquid crystal display device and has the same meaning as a retardation film, an optical compensation film, an optical compensation sheet and the like. In a liquid crystal display device, a retardation film is used for the purpose of improving contrast of a display screen, improving viewing angle characteristics and color.

By using the transparent cellulose ester film of the present invention, a retardation film in which the Re value and the Rth value can be freely controlled can be easily produced.

A plurality of cellulose ester films of the present invention may be laminated, or a cellulose ester film of the present invention and a film other than the present invention may be laminated, and Re or Rth may be appropriately adjusted to be used as a retardation film. The lamination of the film can be carried out using a pressure-sensitive adhesive or an adhesive.

In some cases, the cellulose ester film of the present invention may be used as a support for a retardation film, and an optically anisotropic layer made of liquid crystal or the like may be formed thereon and used as a retardation film. The optically anisotropic layer to be applied to the retardation film of the present invention may be formed from, for example, a composition containing a liquid crystalline compound, or may be formed from a cellulose ester film having birefringence, or from a cellulose ester film of the present invention.

As the liquid crystalline compound, a discotic liquid crystalline compound or a rod-like liquid crystalline compound is preferable.

[Polarizer]

The cellulose ester film or the retardation film of the present invention can be used as a protective film of a polarizing plate (polarizing plate of the present invention). The polarizing plate of the present invention comprises a polarizer and two polarizing plate protective films (transparent films) for protecting both sides thereof, and the cellulose ester film or the retardation film of the present invention can be used as at least one polarizing plate protective film.

When the cellulose ester film of the present invention is used as the polarizing plate protective film, the cellulose ester film of the present invention is subjected to the above surface treatment (described in Japanese Patent Application Laid-Open Nos. 6-94915 and 6-118232) For example, glow discharge treatment, corona discharge treatment, alkali saponification treatment or the like is preferably carried out. In particular, when the cellulose ester constituting the cellulose ester film of the present invention is cellulose acylate, alkali saponification treatment is most preferably used for the surface treatment.

As the polarizer, for example, a film obtained by dipping a polyvinyl alcohol film in an iodine solution and stretching it may be used. When a polarizer in which a polyvinyl alcohol film is immersed in an iodine solution and stretched is used, the surface-treated side of the transparent cellulose ester film of the present invention can be directly bonded to both sides of the polarizer using an adhesive. In the production method of the present invention, it is preferable that the cellulose ester film is directly conjugated with the polarizer. As the adhesive, an aqueous solution of polyvinyl alcohol or polyvinyl acetal (for example, polyvinyl butyral) or a latex of a vinyl-based polymer (for example, polybutyl acrylate) may be used. A particularly preferred adhesive is an aqueous solution of fully saponified polyvinyl alcohol.

Generally, a liquid crystal display device has four polarizing plate protective films because a liquid crystal cell is formed between two polarizing plates. The cellulose ester film of the present invention can be used in any of four polarizing plate protective films. The cellulose ester film of the present invention is a protective film disposed between a polarizer and a liquid crystal layer (liquid crystal cell) in a liquid crystal display device, Can be used. In addition, a transparent hard coat layer, an antiglare layer, an antireflection layer and the like can be formed on the protective film disposed on the opposite side of the cellulose ester film of the present invention with the polarizer interposed therebetween. And is preferably used as a polarizing plate protective film.

[Liquid crystal display device]

The cellulose ester film, the retardation film and the polarizing plate of the present invention can be used in liquid crystal display devices of various display modes. Each liquid crystal mode in which these films are used will be described below. Of these modes, the cellulose ester film, the retardation film and the polarizing plate of the present invention are preferably used in VA mode and IPS mode liquid crystal display devices. These liquid crystal display devices may be either transmissive, reflective or transflective.

(TN type liquid crystal display device)

The cellulose ester film of the present invention may be used as a support of a retardation film of a TN type liquid crystal display device having a TN mode liquid crystal cell. The TN mode liquid crystal cell and the TN type liquid crystal display device have been well known for a long time. The retardation film to be used in the TN type liquid crystal display device is disclosed in JP-A-3-9325, JP-A-6-148429, JP-A-8-50206 and JP- Vol. 36 (1997) p. 143 or Jpn. J. Appl. Phys. Vol. 36 (1997) p. 1068).

(VA type liquid crystal display device)

The cellulose ester film of the present invention is particularly advantageously used as a support for a retardation film or a retardation film of a VA type liquid crystal display device having a VA mode liquid crystal cell. The VA type liquid crystal display device may be, for example, an alignment-divided system described in JP-A-10-123576. In these embodiments, the polarizing plate using the cellulose ester film of the present invention contributes to enlargement of viewing angle and increase of contrast.

(IPS type liquid crystal display device and ECB type liquid crystal display device)

The cellulose ester film of the present invention is particularly advantageously used as a support for a retardation film or a retardation film of an IPS type liquid crystal display device and an ECB type liquid crystal display device having a liquid crystal cell of an IPS mode and an ECB mode, or as a protective film of a polarizing plate. These modes are a mode in which the liquid crystal material is oriented substantially parallel to black display, and liquid crystal molecules are aligned in parallel with the substrate surface in the voltage unapplied state to display black. In these embodiments, the polarizing plate using the cellulose ester film of the present invention contributes to enlargement of viewing angle and increase of contrast.

(Reflective Liquid Crystal Display)

The cellulose ester film of the present invention is also advantageously used as a retardation film of a reflective liquid crystal display of TN type, STN type, HAN type, or GH (Guest-Host) type. These display modes are well known for a long time. The TN type reflection type liquid crystal display device is described in Japanese Laid-Open Patent Publication No. 10-123478, International Publication No. 98/48320, and Japanese Patent No. 3022477. The retardation film used in the reflection type liquid crystal display device is described in the pamphlet of International Publication No. 00/65384.

(Other liquid crystal display devices)

The cellulose ester film of the present invention is also advantageously used as a support for a retardation film of an ASM type liquid crystal display device having a liquid crystal cell of an ASM (Axially Symmetric Aligned Microcell) mode. The liquid crystal cell of the ASM mode is characterized in that the thickness of the cell is held by a position-adjustable resin spacer. The other properties are the same as those of the TN mode liquid crystal cell. The ASM mode liquid crystal cell and the ASM type liquid crystal display device are described in a paper by Kume et al. (Kume et al., SID 98 Digest 1089 (1998)).

(Hard coat film, antiglare film, antireflection film)

The cellulose ester film of the present invention may be applied to a hard coat film, an antiglare film, or an antireflection film, as the case may be. For the purpose of improving the visibility of flat panel displays such as LCDs, PDPs, CRTs, and ELs, any one or both of a hard coat layer, an antiglare layer, and an antireflection layer may be provided on one side or both sides of the transparent cellulose ester film of the present invention have. Preferred embodiments of such an antiglare film and antireflection film are described in detail on pages 54 to 57 of the Invention Association publication (Air No 2001-1745, published on Mar. 15, 2001, Inventors' Association) It can be preferably used also in a cellulose ester film.

(Example)

Hereinafter, the features of the present invention will be described in more detail with reference to Examples and Comparative Examples. The materials, the amounts used, the ratios, the processing contents, the processing procedures, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Accordingly, the scope of the present invention should not be construed as being limited by the following specific examples.

Example 1: Production of cellulose ester film (101)

(Preparation of Cellulose Ester Solution A-1)

The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose ester solution A-1. The acetyl substitution degree was measured according to ASTM D-817-91. The viscosity average degree of polymerization was measured by intrinsic viscosity method such as Uda et al. (Udakazuo, Hideo Saito, "Textile Journal", vol. 18, No. 1, pp. 105-120 (1962)).

Composition of cellulose ester solution A-1

Cellulose ester (acetyl substitution degree: 2.86, viscosity average degree of polymerization: 310)

100 parts by mass

The sugar ester compounds of the general formulas (I) and (II)

The sugar ester compound of the formula (III)

· Methylene chloride 384 parts by mass

Methanol 69 parts by mass

9 parts by mass of butanol

(Preparation of Mat dispersion B-1)

The following composition was put into a dispersing machine and stirred to dissolve each component to prepare a matting agent dispersion B-1.

Composition of matting agent dispersion B-1

Silica particle dispersion (average particle diameter 16 nm)

"AEROSIL R972 ", manufactured by Nippon Aerosil Co., Ltd., 10.0 parts by mass

Methylene chloride 72.8 parts by mass

Methanol 3.9 parts by mass

· Butanol 0.5 part by mass

Cellulose Ester Solution A-1 10.3 parts by mass

(Preparation of ultraviolet absorber solution C-1)

The following composition was put in a separate mixing tank and stirred while heating to dissolve each component to prepare an ultraviolet absorber solution C-1.

Composition of ultraviolet absorber solution C-1

Ultraviolet absorber (UV-1 below) 10.0 parts by mass

Ultraviolet absorber (UV-2 shown below) 10.0 parts by mass

Methylene chloride 55.7 parts by mass

· 10 parts by mass of methanol

1.3 parts by mass of butanol

Cellulose Ester Solution A-1 12.9 parts by mass

[Chemical Formula 9]

(Production of Cellulose Ester Film 101)

The mat release dispersion B-1 was added to the cellulose ester solution A-1 in such an amount that the sugar ester compound of the general formulas (I) to (III) was added in an amount shown in Table 4 per 100 parts by mass of the cellulose ester, -1) and an ultraviolet absorber (UV-2) were added in an amount of 1.0 part by mass, respectively, and the components were dissolved by heating with heating to prepare a dope. The resultant dope was heated to 30 占 폚 and plied onto a mirror-polished stainless steel support having a diameter of 3 m through a flexible machine. The surface temperature of the support was set at -5 DEG C, and the application width was set at 1470 mm. The space temperature of the entire flexible part was set at 15 캜. Then, the cellulose ester film, which was soft and rotated 50 cm before the end portion of the flexible portion, was peeled from the drum, and both ends were clipped with a pin tenter. The residual solvent amount of the cellulose ester web immediately after the peeling was 70% and the film surface temperature of the cellulose ester web was 5 캜.

The cellulose ester web held in a pin tenter was conveyed to a drying zone. In the initial drying, a drying air of 45 ° C was blown. Then, it was dried at 110 DEG C for 5 minutes and further at 140 DEG C for 10 minutes.

The film thickness of the finished cellulose ester film was 60 탆. This film sample 101 was used as the cellulose ester film of Example 1.

[Examples 2 to 9 and Comparative Examples 1 to 6]

(Production of cellulose ester films (102 to 115)

Dope ester compounds or comparative compounds shown in Table 3 were used instead of the sugar ester compounds of the general formulas (I) to (III) used in the preparation of the cellulose ester film 101 to prepare a cellulose ester film 102 To 115).

[Measurement method]

(Method for measuring the average degree of substitution of sucrose benzoate)

The distribution and the average degree of substitution of the substituents of the aromatic sugar ester compound represented by the general formulas (I) and (II) were measured by HPLC under the following conditions, and the peak with a retention time of about 31.5 min was substituted with 8 substituents, 27 to 29 min The peak group in the vicinity of 22 to 25 min is replaced with the 6 substituent, the peak group in the vicinity of 15 to 20 min is replaced with the 5 substituent, the peak group in the vicinity of 8.5 to 13 min is replaced with the quadruple substituent, The peak substituents in the vicinity of 6 min were used as tri-substituents, and the average degree of substitution with respect to the sum of the area ratios was calculated. The results are shown in Table 4 below.

&Quot; HPLC measurement conditions &quot;

Column: TSK-gel ODS-100Z (Toso), 4.6 x 150 mm, lot number (P0014)

Eluent A: H ₂ O = 100,

Eluent B: AR = 100. Both A and B contain 0.1% each of AcOH and NEt ₃

Flow rate: 1 ml / min,

Column temperature: 40 DEG C,

Wavelength: 254 nm,

Sensitivity: AUX2,

Injection amount: 10 [mu] L,

Rinse solution: THF / H ₂ O = 9/1 (vol ratio)

Sample concentration: 5 mg / 10 ml (THF)

[evaluation]

(Surface fault)

The cellulose ester film was rolled up in a rolled form, and the size of 100 mm x 100 mm was cut from the original wound. Observation was made under a cross-nicol using a polarization microscope at a magnification of 30 times, and the following evaluation Respectively. The foreign substance is a bleed-out component derived from the additive, contamination on the surface, or precipitate inside or on the surface, and observed as a bright spot under a polarization microscope.

○: Number of foreign substances 0 to 9

?: Number of foreign substances 10 to 50

X: Number of foreign substances: 51 or more

The results obtained are shown in Table 4 below.

(Optical performance time-course change)

The cellulose ester film was measured for Rth at a wavelength of 590 nm at a relative humidity of 60% at 25 DEG C by an automatic birefringence meter (KOBRA-WR, Oji Measurement Co., Ltd.). After storing for 20 days under conditions of 63 캜 and a relative humidity of 90%, Rth was measured under the same measurement conditions. The difference in Rth before and after storage under high-temperature and high-humidity conditions is shown in Table 4 below as a change in optical performance over time.

(Time-course change of polarizer)

1) saponification of the film

The obtained film was immersed in a 1.5 mol / l NaOH aqueous solution (saponification solution) maintained at 55 캜 for 2 minutes, and then the film was washed with water and then immersed in a 0.05 mol / l sulfuric acid aqueous solution at 25 캜 for 30 seconds Thereafter, the film was allowed to pass through a further rinsing bath for 30 seconds under running water to make the film neutral. Then, the water removal by the air knife was repeated three times. After the water was removed, the film was stood in a drying zone at 70 캜 for 15 seconds and dried to prepare a saponified film.

2) Preparation of Polarizer

According to Example 1 of Japanese Laid-Open Patent Publication No. 2001-141926, iodine was adsorbed on a stretched polyvinyl alcohol film to prepare a polarizer having a thickness of 20 占 퐉.

3) Integration

Using the polyvinyl alcohol-based adhesive, the cellulose ester film 101 prepared on both sides of the polarizer was attached and dried at 70 DEG C for 10 minutes or more. The obtained polarizing plate was used as the polarizing plate 101. In the same manner, the cellulose ester films (102 to 125) were used to prepare the polarizing plates (102 to 125).

4) Evaluation of Polarizer

Two samples of the polarizing plates were prepared by cementing one side of the film side of the polarizing plate onto a glass plate with a pressure sensitive adhesive. The two samples were placed in Cross-Nicol and the transmittance was measured (initial transmittance at 25 deg. C, relative humidity 60%). Further, the sample was allowed to stand at a temperature of 63 DEG C and a relative humidity of 90% for 1000 hours, after which it was further left at 25 DEG C and a relative humidity of 60% for 5 hours or more, Lt; / RTI &gt; transmittance). The value obtained by multiplying the maximum transmittance and the transient transmittance at a wavelength in the range of 400 nm to 500 nm by 100 was defined as a time-course change of the polarizing plate. A spectrophotometer "U-3210" (Hitachi, Ltd.) was used to measure the transmittance.

The results obtained are shown in the following Table 4 as changes in polarizer plate over time.

(Hayes)

The haze was measured in accordance with JIS K-6714 with a haze meter (HGM-2DP, Suga Tester) at a temperature of 25 ° C and a relative humidity of 60% at a film sample of 40 mm × 80 mm. As to the haze of 1.0% or more, it is determined that the haze is increased, and the reason why the haze is increased is shown in Table 4 below.

(Bleed out)

The bleed-out was evaluated as to whether precipitation of the additive occurred after 1000 hours of elapse at a temperature of 60 deg. C and a humidity of 90% and a humidity of 10 deg. C at a temperature of 80 deg. C after drying. Table 4 shows the reason for bleed-out.

* 1) Figures in parentheses indicate the addition amount (parts by mass) to 100 parts by mass of cellulose acylate.

It can be seen from Table 4 that the cellulose ester film containing a mixture of the aromatic sugar ester and the aliphatic sugar ester satisfying the range of the present invention has a small surface defect and a small optical performance over time and also shows a change in the time- And thus it was found that it is excellent as a protective film. From the results of Example 7, it was found that when a substituent having an average degree of substitution of 4.0 of sucrose benzoate, which is an aromatic sugar ester, was used as the compound of the general formulas (I) and (II), the time course of the polarizing plate tended to change. From Example 9, it was found that when a compound of a glucose residue, which is a monosaccharide skeleton (pyranose skeleton), is used as an aliphatic sugar ester which is a compound of the general formula (III), the time course of the polarizing plate tends to increase there was.

On the other hand, from Comparative Examples 1 and 2, when the substitution degree of sucrose benzoate, which is an aromatic sugar ester, as the compound of the general formulas (I) and (II) It was found that a problem of occurrence occurred.

In Comparative Examples 3 to 5, when only the aromatic sugar ester as the compound of the general formulas (I) and (II) was used alone and the aliphatic sugar ester as the compound of the general formula (III) was not used, I realized that the enemy change becomes bigger.

From Comparative Example 6, it was found that when only the aliphatic sugar ester as the compound of the general formula (III) was used alone and the aromatic sugar ester as the compound of the general formulas (I) and (II) was not used, .

From Comparative Example 7, it was found that when a comparative compound other than the sugar ester of the general formulas (I) to (III) was used, a plane failure caused by the vaporization property of the additive was generated.

[Example 9]

A sample (401) was prepared in the same manner as in the sample (103) of Example 1, except that the cellulose ester was replaced with a material having an acetyl substitution degree of 2.94. The sample 401 obtained the same good results as the sample 103.

[Examples 101 to 103]

(Formation of Coating of Hard Coat Layer Coating Film)

The hard coat layer was applied to the samples (101, 102, 109) obtained in Examples 1, 2, and 8 in the following manner. Of the following hard coatings 1 to 4, the hard coating 1 was used for the sample 101, the hard coating 4 was used for the sample 102, and the hard coating 3 was used for the sample 109.

The hard coats 1 to 4 are the compositions shown in Table 3 below, and the UV initiator 1 has the structure shown in the following table.

The photopolymerizable monomer used for the hard coats 1 to 3 is PET30 manufactured by Nippon Yakusho Co., Ltd., and the monomer used for the hard coat 4 is KAYARAD DPHA manufactured by Nippon Yakuhin K.K.

[Chemical formula 10]

IRGACURE127 from Chiba Japan Co., Ltd. was used as the UV initiator (1).

The coating conditions of the hard coat were applied by hand using a bar coater of the number 8 and then dried at 100 DEG C for 60 seconds to cure by irradiating UV at 1.5 kW and 300 mJ under the condition of 0.1% or less of nitrogen.

(Evaluation of adhesion)

The adhesion after light irradiation was evaluated by the following method.

A crosscut test according to JIS K 5600 was carried out. Specifically, 11 cutting lines were vertically and horizontally arranged at intervals of 1 mm on the surface of the sample after hardcoat application and UV curing, thereby making 100 checkerboard scales of 1 mm in width and height. The cellophane tape and the mylar tape were pasted thereon. The cellophane tape and the mylar tape were fastened and peeled off. The peeled points were closely evaluated by visual observation. The sample was subjected to humidity control for 2 hours or more in a room at a temperature of 25 占 폚 and a humidity of 60% before the adhesion evaluation, and then evaluated.

The result of adhesion evaluation after Xe irradiation for 24 hours before inserting the cutting line is the adhesion result of light 24 h in Table 1, and the result of adhesion evaluation after Xe irradiation for 48 hours is the result of adhering light fastness 48 h. The result of adhesion evaluation without conducting Xe irradiation is an initial adhesion evaluation.

Adhesiveness: Peeling point 0 to 10 graduations

Adhesion?: Peeling point 11 to 49 graduations

Adhesion X: Peeling point 50 to 99 graduations

Adhesion ××: Peeling point 100 or more (All parts with tape attached)

Super Xenon Weatherometer X75 manufactured by Suga Test Instruments Co., Ltd. was used for the investigation of Xe.

As a result, all were found to be evaluated in the Xe 24 hours.

(Pencil hardness evaluation)

The pencil hardness was evaluated by the following method.

After the hardcoat application and the UV curing, the sample was conditioned for 2 hours under the conditions of 25 ° C and 60% relative humidity, and then the test pencil specified by JIS S 6006 was used. According to the pencil hardness evaluation method prescribed by JIS K 5400, Using a weight of 500 g, scratches were repeated 5 times with a pencil of each hardness, and the hardness until no scratches more than 4 times was measured as OK. In addition, it is described that the scratch defined by JIS K 5400 is a tear of the coating film, a scratch of the coating film, and not a denting of the coating film. In this case, it is judged as a scratch including dents of the coating film. The larger the number, the higher the hardness.

As a result, it was found that all of them were good (OK evaluation at all 3H).

[Example 301: Mounting test for IPS mode liquid crystal display device]

The cellulose ester film 101 and a commercially available cellulose ester film (Z-Tak, manufactured by Fuji Photo Film Co., Ltd.) were saponified in the same manner as in Example 1. Using a polyvinyl alcohol-based adhesive, the polarizer prepared in Example 1 was sandwiched between two films and dried at 70 DEG C for 10 minutes or more.

The transmission axis of the polarizer and the slow axis of the cellulose ester film thus prepared were arranged so as to be parallel to each other. The transmission axis of the polarizer and the slow axis of a commercially available cellulose triacylate film were arranged to be orthogonal.

(Liquid crystal cell)

The liquid crystal cell, the electrode, and the substrate may be IPS as used conventionally. The orientation of the liquid crystal cell is in the horizontal orientation, and those developed and marketed for IPS liquid crystals can be used. The physical properties of the liquid crystal cell were Δn of the liquid crystal: 0.099, the cell gap of the liquid crystal layer: 3.0 μm, the pretilt angle: 5 °, and the rubbing direction:

(Mounting on IPS panel)

A polarizing plate having the cellulose ester film 101 on the lower polarizing plate (backlight side) of the liquid crystal display device using the vertical alignment liquid crystal cell and the polarizing plate having the cellulose ester film on the lower polarizing plate (backlight side) were provided so as to be on the side of the Z- . The upper polarizer and the lower polarizer were attached to the liquid crystal cell via a pressure-sensitive adhesive. The cross-Nicole arrangement was such that the transmission axis of the upper polarizer was in the vertical direction and the transmission axis of the lower polarizer was in the horizontal direction.

(Contrast ratio: 10) from black display (L1) to white display (L8) using a measuring device (EZ-Contrast 160D, manufactured by ELDIM) with the ratio of transmittance (white display / black display) And a polar angle range on the black side without gradation reversal) was measured.

Observation of the manufactured liquid crystal display device revealed that the liquid crystal panel using the film of the present invention could realize a neutral black display in either the front direction or the viewing angle direction.

[Example 302]

Sample 501 was prepared in the same manner as Sample 1 of Example 1, except that the film thickness was changed to 40 占 퐉. Using this, a polarizing plate was produced in the same manner as in Example 301, and a mounting experiment was performed on the IPS mode liquid crystal display. The IPS liquid crystal panel in which this polarizing plate was mounted exhibited a neutral black display in the front direction and was good.

Claims (13)

Cellulose ester,
An aromatic sugar ester compound represented by the following general formula (I)
An aromatic sugar ester compound represented by the following general formula (II)
An aliphatic sugar ester compound represented by the following general formula (III)
Wherein the aromatic ester compound represented by the general formula (I) and the aromatic sugar ester compound represented by the general formula (II) have an average ester substitution degree of less than 94%.
(I) (HO) mG- (LR ¹ ) n
(II) (HO) pG- ( LR 1) q
(III) (HO) t-G '- (L'-R ² ) r
(In the general formulas (I) to (III), G and G 'each independently represent monosaccharide residue or 2 sugar residue.) Each R ¹ independently represents an aliphatic group or aromatic group, and at least one represents an aromatic group. R ² represents an aliphatic, each independently. L and L 'each independently represents a divalent linking group. m represents an integer of 1 or more, p represents an integer of 0 or more, n and q are each independently an integer of 1 or more M + n? 4, p + q? 4, m > p, n < q, and m + n And p + q are the same as the number of hydroxyl groups in the case where G is not a residue but a non-substituted saccharide of a cyclic acetal structure having the same skeleton, and r + t is the same skeleton as G ' Unsubstituted saccharides of the cyclic acetal structure of Is the same as the number of hydroxyl groups in the case of &lt; RTI ID = 0.0 &gt; The method according to claim 1,
Wherein the R &lt; ² &gt; in the general formula (III) represents two or more aliphatic groups. The method according to claim 1,
Wherein the G 'in the formula (III) represents a residue of two sugars. The method according to claim 1,
Wherein G in the general formula (I) and the general formula (II) is a sucrose skeleton and the average ester substitution of the aromatic sugar ester compound represented by the general formula (I) and the aromatic sugar ester compound represented by the general formula (II) Wherein the cellulose ester film has a degree of polymerization of 5 to 7.5. 5. The method of claim 4,
The addition amount of the aromatic sugar ester having q of 8 in the general formula (II) is preferably 20 (meth) acrylate based on the total amount of the aromatic sugar ester compound represented by the general formula (I) and the aromatic sugar ester compound represented by the general formula % By mass of the cellulose ester film. The method according to claim 1,
The L in the general formula (I) and the general formula (II) and the L 'in the general formula (III) are each independently a single bond, -O-, -CO-, -NR ¹¹ - (R ¹¹ Represents a monovalent substituent). &Lt; / RTI &gt; The method according to claim 1,
The cellulose ester film according to claim ¹ , wherein R ¹ in formula (I) and R ² in formula (III) each independently represents an acyl group. The method according to claim 1,
A cellulose ester film characterized in that the R ¹ in the general formula (I) and the general formula (II) represents a benzoyl group. The method according to claim 1,
Wherein the R &lt; ² &gt; in the general formula (III) each independently represents a non-cyclic aliphatic group. The method according to claim 1,
Wherein at least one of R &lt; ² &gt; in the general formula (III) represents a branched aliphatic group. The method according to claim 1,
Wherein the R &lt; ² &gt; in the general formula (III) comprises an acetyl group and an isobutyryl group only. A polarizer, and a protective film disposed on both sides of the polarizer,
Wherein at least one of the protective films is a cellulose ester film according to any one of claims 1 to 11. A liquid crystal cell and a polarizing plate disposed on both sides of the liquid crystal cell,
And at least one of the polarizing plates is the polarizing plate according to claim 12.