JP5575007B2 - Cellulose acylate film, polarizing plate, and liquid crystal display device - Google Patents

Description

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

  Liquid crystal display devices are increasingly used year by year as space-saving image display devices with low power consumption. The basic configuration of a liquid crystal display device is one in which polarizing plates are provided on both sides of a liquid crystal cell. The polarizing plate plays a role of allowing only light having a polarization plane in a certain direction to pass through, and the performance of the liquid crystal display device is greatly influenced by the performance of the polarizing plate. The polarizing plate generally has a configuration in which transparent protective films are bonded to both front and back sides of a polarizer made of a polyvinyl alcohol film or the like on which iodine or dye is adsorbed and oriented. A cellulose acylate film typified by cellulose acetate has been widely used as a polarizing plate protective film because it has high transparency and can easily ensure adhesion with polyvinyl alcohol used in a polarizer.

  In recent years, as the use of liquid crystal display devices has been expanded, large-size and high-quality applications such as televisions have been expanded, and higher quality is required for polarizing plates, retardation films, and polarizing plate protective films. ing. Among them, large-size and high-quality liquid crystal display devices are required to be used in harsher environments as compared to conventional liquid crystal display devices. Cellulose acylate films used in the liquid crystal display devices have performance that depends on environmental humidity. Reduction of change has been desired.

  In order to reduce the performance change depending on the environmental humidity of cellulose acylate film, it is effective to reduce the moisture content of the film. So far, various compounds have been added to the cellulose acylate film to make it hydrophobic. Is disclosed.

  For example, Patent Document 1 discloses a method of adding a rosin compound, Patent Document 2 discloses a polyhydric alcohol ester having an aromatic ring or cycloalkyl ring in the molecule, and an aromatic ring or cycloalkyl ring in the molecule. A method of adding glycolates is disclosed. However, in the method of adding the compounds described in these patent documents, the effect of reducing the moisture content is insufficient when added in a small amount. On the other hand, when added in a large amount, the additive precipitates on the film surface and the transparency of the film. There were problems such as damage.

  On the other hand, Patent Document 3 proposes a technique for suppressing precipitates in a film of an acrylic polymer additive and a cellulose ester, and is excellent in productivity because precipitates and volatiles are hardly generated during production. In addition, it is described that a film having low retentivity and moisture permeability can be provided. Similarly, Patent Document 4 describes that an optical compensation film with little retardation change due to environmental fluctuation can be provided in a film of an acrylic polymer additive and a cellulose ester.

JP 2002-146044 A JP 2003-232920 A JP 2003-012859 A JP 2007-231157 A

  However, even in the methods of adding the polymers described in Patent Documents 3 and 4, when the molecular weight of the additive is large and / or when it is added in a large amount, there is a problem that the transparency of the film is impaired, and further improvement is required. It was done.

The present invention aims to solve the above-mentioned problems, and the problem to be solved by the present invention is to provide a cellulose acylate film having a low moisture content and excellent transparency.

  As a result of intensive studies by the present inventors, it has been found that the above problem can be solved by adding a polymer having a specific β-ketoester structure to a cellulose acylate film. 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 configuration.

（式中Ｒ¹は水素原子、脂肪族基、芳香族基、複素環基を表し、前記脂肪族基、芳香族基および複素環基は置換基を有していてもよい。Ｌは単結合、２価の脂肪族基、２価の芳香族基、２価の複素環基、−Ｃ（＝Ｏ）−、−Ｏ−、−Ｎ（Ｒ²）−またはそれらの組合せを表し、前記２価の脂肪族基、２価の芳香族基および２価の複素環基は置換基を有していてもよい。Ｒ²は水素原子またはアルキル基を表す。）
［２］ 前記一般式（１）で表されるエチレン性不飽和モノマーを重合して得られるポリマー、または前記一般式（１）で表されるエチレン性不飽和モノマーと少なくとも１種のその他のエチレン性不飽和モノマーとを共重合させて得られるポリマーが、下記一般式（２）で表される繰り返し単位を含むポリマーであることを特徴とする［１］に記載のセルロースアシレートフィルム。

（式中、Ｒ¹は水素原子、脂肪族基、芳香族基または複素環基を表し、前記脂肪族基、芳香族基および複素環基は置換基を有していてもよい。Ｌは、単結合、あるいは、２価の脂肪族基、２価の芳香族基、２価の複素環基、−Ｃ（＝Ｏ）−、−Ｏ−、−Ｎ（Ｒ²）−またはそれらの組合せを表し、前記２価の脂肪族基、２価の芳香族基および２価の複素環基は置換基を有していてもよい。Ｒ²は水素原子またはアルキル基を表す。）
［３］ 前記一般式（１）または（２）におけるＲ¹が水素原子またはメチル基であり、Ｌが２価の脂肪族基、２価の芳香族基、−Ｃ（＝Ｏ）−、または−Ｌ¹−Ｌ²−であることを特徴とする［１］または［２］に記載のセルロースアシレートフィルム（但し、Ｌ¹およびＬ²の一方が、−Ｃ（＝Ｏ）−、−Ｏ−、−Ｎ（Ｒ²）−またはそれらの組合せを表し、他方が２価の脂肪族基、２価の芳香族基、２価の複素環基を表す。前記２価の脂肪族基、２価の芳香族基および２価の複素環基は置換基を有していてもよい。Ｒ²は水素原子またはアルキル基を表す。）。
［４］ 前記一般式（１）で表されるエチレン性不飽和モノマーがアセト酢酸エチルメタクリレートまたはアセト酢酸エチルアクリレートであることを特徴とする［１］〜［３］のいずれか一項に記載のセルロースアシレートフィルム。
［５］ 前記一般式（１）で表されるエチレン性不飽和モノマーを重合して得られるポリマー、または前記一般式（１）で表されるエチレン性不飽和モノマーと少なくとも１種のその他のエチレン性不飽和モノマーとを共重合させて得られるポリマーが、前記一般式（１）で表されるエチレン性不飽和モノマーと少なくとも１種のその他のエチレン性不飽和モノマーとを共重合させて得られるポリマーであることを特徴とする［１］〜［４］のいずれか一項に記載のセルロースアシレートフィルム。
［６］ 前記その他のエチレン性不飽和モノマーが、（メタ）アクリル酸エステル、（メタ）アクリロニトリル、（メタ）アクリロイルモルホリンおよび（メタ）アクリルアミドからなる群から選ばれる少なくとも１つであることを特徴とする［１］〜［５］のいずれか一項に記載のセルロースアシレートフィルム。
［７］ 前記一般式（１）で表されるエチレン性不飽和モノマーを重合して得られるポリマー、または前記一般式（１）で表されるエチレン性不飽和モノマーと少なくとも１種のその他のエチレン性不飽和モノマーとを共重合させて得られるポリマーが重量平均分子量５００〜３００，０００であることを特徴とする［１］〜［６］のいずれか一項に記載のセルロースアシレートフィルム。
［８］ 前記一般式（１）で表される繰り返し単位を含むポリマーが重量平均分子量１０，０００を超え３００，０００以下であることを特徴とする［１］〜［６］のいずれか一項に記載のセルロースアシレートフィルム。
［９］ 前記一般式（１）で表されるエチレン性不飽和モノマーを重合して得られるポリマー、または前記一般式（１）で表されるエチレン性不飽和モノマーと少なくとも１種のその他のエチレン性不飽和モノマーとを共重合させて得られるポリマーが重量平均分子量１００，０００〜３００，０００であることを特徴とする［１］〜［６］のいずれか一項に記載のセルロースアシレートフィルム。
［１０］ 前記一般式（１）で表されるエチレン性不飽和モノマーを重合して得られるポリマー、または前記一般式（１）で表されるエチレン性不飽和モノマーと少なくとも１種のその他のエチレン性不飽和モノマーとを共重合させて得られるポリマーを、前記セルロースアシレート１００質量部に対して２０〜１００質量部含むことを特徴とする［１］〜［９］のいずれか一項に記載のセルロースアシレートフィルム。
［１１］ 前記セルロースアシレートが下記式（３）を満たすことを特徴とする［１］〜［１０］のいずれか一項に記載のセルロースアシレートフィルム。
式（３）
１．５≦Ａ≦３．０
（式中、Ａはセルロースアシレートの総アシル置換度を表す。）
［１２］ 前記セルロースアシレートが下記式（４）を満たすことを特徴とする［１］〜［１１］のいずれか一項に記載のセルロースアシレートフィルム。
式（４）
２．０≦Ｂ≦３．０
（式中、Ｂはセルロースアシレートのアセチル置換度を表す。）
［１３］ ヘイズが１％以下であることを特徴とする［１］〜［１２］のいずれか一項に記載のセルロースアシレートフィルム
［１４］ ２５℃相対湿度８０％における含水率が４％以下であることを特徴とする［１］〜［１３］のいずれか一項に記載のセルロースアシレートフィルム。
［１５］ 偏光子と、該偏光子の両側に二枚の保護フィルムを有し、該保護フィルムのうち少なくとも一枚が［１］〜［１４］のいずれか一項に記載のセルロースアシレートフィルムであることを特徴とする偏光板。
［１６］液晶セルと該液晶セルの両側に配置された二枚の偏光板からなり、該偏光板のうち少なくとも一枚が［１５］に記載の偏光板であることを特徴とする液晶表示装置。 [1] A polymer obtained by polymerizing cellulose acylate and an ethylenically unsaturated monomer represented by the following general formula (1), or an ethylenically unsaturated monomer represented by the following general formula (1) and at least 1 cellulose acylate film characterized by containing a polymer obtained and other ethylenically unsaturated monomer species by copolymerizing.
General formula (1)

(In the formula, R ¹ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and the aliphatic group, aromatic group and heterocyclic group may have a substituent. L represents a single bond. A divalent aliphatic group, a divalent aromatic group, a divalent heterocyclic group, —C (═O) —, —O—, —N (R ² ) —, or a combination thereof; The valent aliphatic group, divalent aromatic group, and divalent heterocyclic group may have a substituent, and R ² represents a hydrogen atom or an alkyl group.)
[2] A polymer obtained by polymerizing the ethylenically unsaturated monomer represented by the general formula (1), or the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylene The cellulose acylate film as described in [1], wherein the polymer obtained by copolymerizing the unsaturated unsaturated monomer is a polymer containing a repeating unit represented by the following general formula (2).

(In the formula, R ¹ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and the aliphatic group, aromatic group and heterocyclic group may have a substituent. L is A single bond, a divalent aliphatic group, a divalent aromatic group, a divalent heterocyclic group, —C (═O) —, —O—, —N (R ² ) —, or a combination thereof. And the divalent aliphatic group, divalent aromatic group and divalent heterocyclic group may have a substituent, and R ² represents a hydrogen atom or an alkyl group.)
[3] R ¹ in the general formula (1) or (2) is a hydrogen atom or a methyl group, L is a divalent aliphatic group, a divalent aromatic group, —C (═O) —, or -L ¹ -L ² - characterized in that it is a [1] or [2] the cellulose acylate film (although described, is one of L ¹ and ^{L 2, -C (= O)} -, - O -, -N (R ² )-or a combination thereof, and the other represents a divalent aliphatic group, a divalent aromatic group, or a divalent heterocyclic group. The valent aromatic group and the divalent heterocyclic group may have a substituent, and R ² represents a hydrogen atom or an alkyl group.
[4] The ethylenically unsaturated monomer represented by the general formula (1) is ethyl acetoacetate methacrylate or ethyl acetoacetate acrylate, according to any one of [1] to [3] Cellulose acylate film.
[5] A polymer obtained by polymerizing the ethylenically unsaturated monomer represented by the general formula (1), or the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylene A polymer obtained by copolymerizing an ethylenically unsaturated monomer is obtained by copolymerizing the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylenically unsaturated monomer. The cellulose acylate film according to any one of [1] to [4], which is a polymer.
[6] The other ethylenically unsaturated monomer is at least one selected from the group consisting of (meth) acrylic acid ester, (meth) acrylonitrile, (meth) acryloylmorpholine, and (meth) acrylamide. The cellulose acylate film according to any one of [1] to [5].
[7] A polymer obtained by polymerizing the ethylenically unsaturated monomer represented by the general formula (1), or the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylene The cellulose acylate film according to any one of [1] to [6], wherein a polymer obtained by copolymerizing a polymerizable unsaturated monomer has a weight average molecular weight of 500 to 300,000.
[8] Any one of [1] to [6], wherein the polymer containing the repeating unit represented by the general formula (1) has a weight average molecular weight of more than 10,000 and not more than 300,000. The cellulose acylate film described in 1.
[9] A polymer obtained by polymerizing the ethylenically unsaturated monomer represented by the general formula (1), or the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylene The cellulose acylate film according to any one of [1] to [6], wherein the polymer obtained by copolymerization with the unsaturated unsaturated monomer has a weight average molecular weight of 100,000 to 300,000. .
[10] A polymer obtained by polymerizing the ethylenically unsaturated monomer represented by the general formula (1), or the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylene [20] The polymer obtained by copolymerizing with the unsaturated unsaturated monomer is contained in an amount of 20 to 100 parts by mass with respect to 100 parts by mass of the cellulose acylate, according to any one of [1] to [9]. Cellulose acylate film.
[11] The cellulose acylate film according to any one of [1] to [10], wherein the cellulose acylate satisfies the following formula (3).
Formula (3)
1.5 ≦ A ≦ 3.0
(In the formula, A represents the total acyl substitution degree of cellulose acylate.)
[12] The cellulose acylate film according to any one of [1] to [11], wherein the cellulose acylate satisfies the following formula (4).
Formula (4)
2.0 ≦ B ≦ 3.0
(In the formula, B represents the degree of acetyl substitution of cellulose acylate.)
[13] The cellulose acylate film according to any one of [1] to [12], wherein the water content at 25 ° C. and a relative humidity of 80% is 4% or less. The cellulose acylate film according to any one of [1] to [13], which is characterized in that
[15] The cellulose acylate film according to any one of [1] to [14], which has a polarizer and two protective films on both sides of the polarizer, and at least one of the protective films is [1] to [14]. A polarizing plate characterized by the above.
[16] A liquid crystal display device comprising a liquid crystal cell and two polarizing plates disposed on both sides of the liquid crystal cell, wherein at least one of the polarizing plates is the polarizing plate according to [15]. .

  According to the present invention, a cellulose acylate film having a low moisture content and excellent transparency can be provided. In addition, a retardation film and a polarizing plate using the cellulose acylate film can be provided, and a liquid crystal display device having good display quality using the polarizing plate can be provided.

It is a schematic sectional drawing of an example of the polarizing plate of this invention.

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

（式中Ｒ¹は水素原子、脂肪族基、芳香族基、複素環基を表し、前記脂肪族基、芳香族基および複素環基は置換基を有していてもよい。Ｌは単結合、２価の脂肪族基、２価の芳香族基、２価の複素環基、−Ｃ（＝Ｏ）−、−Ｏ−、−Ｎ（Ｒ²）−またはそれらの組合せを表し、前記２価の脂肪族基、２価の芳香族基および２価の複素環基は置換基を有していてもよい。Ｒ²は水素原子またはアルキル基を表す。）
以下、本発明のセルロースアシレートフィルムの好ましい態様についてより詳細に説明する。 [Cellulose acylate film]
The cellulose acylate film of the present invention (hereinafter also referred to as the film of the present invention) is a polymer obtained by polymerizing cellulose acylate and an ethylenically unsaturated monomer represented by the following general formula (1), or the following general A polymer obtained by copolymerizing an ethylenically unsaturated monomer represented by the formula (1) and at least one other ethylenically unsaturated monomer (hereinafter also referred to as a polymer having a specific β-ketoester structure) It is characterized by containing.
General formula (1)

(In the formula, R ¹ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and the aliphatic group, aromatic group and heterocyclic group may have a substituent. L represents a single bond. A divalent aliphatic group, a divalent aromatic group, a divalent heterocyclic group, —C (═O) —, —O—, —N (R ² ) —, or a combination thereof; The valent aliphatic group, divalent aromatic group, and divalent heterocyclic group may have a substituent, and R ² represents a hydrogen atom or an alkyl group.)
Hereinafter, preferred embodiments of the cellulose acylate film of the present invention will be described in more detail.

<Polymer having specific β-ketoester structure>
The polymer having the specific β-ketoester structure has a high performance for reducing the moisture content of the cellulose acylate film, and has a good affinity with the cellulose acylate, so that a highly transparent film can be realized. Without being bound by any theory, the film of the present invention has significantly improved compatibility by the interaction of the β-ketoester structure in the general formula (1) with hydrogen atoms in cellulose acylate, High transparency can be maintained.
Hereinafter, preferred embodiments of the structure of a polymer having a specific β-ketoester structure, the amount added in the cellulose acylate film, and the like will be described.

(Repeating unit represented by general formula (2))
The polymer having the specific β-ketoester structure is preferably a polymer containing a repeating unit represented by the following general formula (2).

In general formula (2), R ¹ represents a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group, and the aliphatic group, aromatic group, and heterocyclic group may have a substituent. L is a single bond, a divalent aliphatic group, a divalent aromatic group, a divalent heterocyclic group, —C (═O) —, —O—, —N (R ² ) — or those And the divalent aliphatic group, divalent aromatic group and divalent heterocyclic group may have a substituent. R ² represents a hydrogen atom or an alkyl group.

R ¹ in the general formula (1) or (2) represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and the aliphatic group, the aromatic group and the heterocyclic group have a substituent. May be.
Examples of the aliphatic group for R ¹ include an alkyl group, an alkenyl group, an alkynyl group, and a cycloalkyl group. Among them, an alkyl group having 1 to 6 carbon atoms is preferable, and a methyl group is more preferable.
Examples of the aromatic group in R ¹ include a phenyl group, a naphthyl group, and a biphenyl group, and among them, a phenyl group is preferable.
Examples of the heterocyclic group include pyridyl group, pyrrolidyl group, piperidyl group, piperazol group, pyrrolyl group, morpholino group, thiamorpholino group, imidazolyl group, pyrazolyl group, pyrrolidonyl group, and piperidonyl group. Group and pyridyl group are preferred.
Examples of the substituent that the aliphatic group, aromatic group or heterocyclic group may have include an alkyl group having 1 to 6 carbon atoms (for example, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group). , Cyclopentyl, cyclohexyl group), alkenyl group having 2 to 6 carbon atoms (for example, vinyl group, allyl group, 2-butenyl group, 3-pentenyl group, etc.), alkynyl group having 2 to 6 carbon atoms ( For example, propargyl group, 3-pentynyl group, etc.), amino group (for example, amino group, methylamino group, dimethylamino group, diethylamino group, dibenzylamino group), alkoxy group (for example, methoxy group, ethoxy group, butoxy group) Group), an aryloxy group (for example, phenyloxy group, 2-naphthyloxy group), an acyl group (for example, Acetyl group, benzoyl group, formyl group, pivaloyl group), alkoxycarbonyl group (for example, methoxycarbonyl group, ethoxycarbonyl group), aryloxycarbonyl group (for example, phenyloxycarbonyl group), acyloxy group (for example, acetoxy group, benzoyloxy group). ), Acylamino groups (eg acetylamino group, benzoylamino group), alkoxycarbonylamino groups (eg methoxycarbonylamino group), aryloxycarbonylamino groups (eg (phenyloxycarbonylamino group)), sulfonylamino groups (eg methanesulfonylamino) Group, benzenesulfonylamino group), sulfamoyl group (for example, sulfamoyl group, methylsulfamoyl group, dimethylsulfamoyl group, phenylsulfamoyl group), A vamoyl group (for example, carbamoyl group, methylcarbamoyl group, diethylcarbamoyl group, phenylcarbamoyl group), alkylthio group (for example, methylthio group, ethylthio group), arylthio group (for example, phenylthio group), sulfonyl group (for example, mesyl group, tosyl group), Sulfinyl group (eg, methanesulfinyl group, benzenesulfinyl group), ureido group (eg, ureido group, methylureido group, phenylureido group), phosphoric acid amide group (eg, diethylphosphoric acid amide, phenylphosphoric acid amide), hydroxy group, mercapto Group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (for example, imi group) A dazolyl group, a pyridyl group, a quinolyl group, a furyl group, a piperidyl group, a morpholino group, a benzoxazolyl group, a benzimidazolyl group, a benzthiazolyl group) and a silyl group (for example, a trimethylsilyl group, a triphenylsilyl group). Of these, a methyl group and a fluoro group are preferred.
R ¹ in the general formula (1) or the general formula (2) is preferably a hydrogen atom or an aliphatic group, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, a hydrogen atom or a methyl group. It is particularly preferred that it is a methyl group.

L in the general formula (1) or the general formula (2) is a single bond, a divalent aliphatic group, a divalent aromatic group, a divalent heterocyclic group, -C (= O)-, -O. —, —N (R ² ) — or a combination thereof, wherein the divalent aliphatic group, divalent aromatic group and divalent heterocyclic group may have a substituent.
L is preferably a divalent aliphatic group, a divalent aromatic group, —C (═O) —, or —L ¹ —L ² — (provided that ^one of L ¹ and L ² is , —C (═O) —, —O—, —N (R ² ) — or a combination thereof, the other being a divalent aliphatic group, a divalent aromatic group, or a divalent heterocyclic group. The divalent aliphatic group, divalent aromatic group and divalent heterocyclic group may have a substituent, and R ² represents a hydrogen atom or an alkyl group. Here, in the -L ¹ -L ^2-, L ¹ is linked to the main chain.
The L is more preferably -L ¹ -L ^2- .
In the L, L ¹ is —C (═O) —, —O—, —N (R ² ) —, or a combination thereof, and L ² is a divalent aliphatic group or divalent aromatic. And particularly preferably a divalent heterocyclic group.

The divalent aliphatic group in L is preferably an alkylene group or an alkynyl group, more preferably an alkylene group which may have a substituent having 1 to 5 carbon atoms, and an ethylene group. More particularly preferred.
The divalent aromatic group in L is preferably an aromatic group having 6 to 12 carbon atoms, preferably a phenylene group or a naphthylene group, and may be a phenylene group which may have a substituent. More preferred is an unsubstituted phenylene group.
Examples of the divalent heterocyclic group in L include a pyridylene group, a pyrrolidylene group, a piperidylene group, a piperazylene group, a pyrrolylene group, a morpholinylene group, a thiamorpholinen group, an imidazolylene group, a pyrazolylene group, a pyrrolidonylene group, and a piperidylene group. Among them, a morpholinylene group is preferable.
Examples of the substituent that the divalent aliphatic group, divalent aromatic group and divalent heterocyclic group may have include an alkyl group and a halogen group, and among them, an alkyl group Is preferable, an alkyl group having 1 to 6 carbon atoms is more preferable, and a methyl group is particularly preferable.

The L ¹ is preferably —C (═O) —, —O—, —N (R ² ) — or a combination thereof, and the —C (═O) —, —O—, —N ( R ² ) — or a combination thereof includes —C (═O) —, —O—, —C (═O) —O—, —O—C (═O) —, —N (R ² ) —. C (═O) —, —C (═O) —N (R ² ) —, and —N (R ² ) —C (═O) —N (R ² ) — are preferred. Further, L ¹ is more preferably —C (═O) —O— or —C (═O) —N (R ² ) —, and particularly preferably —C (═O) —O—. preferable.
L ² is preferably a divalent aliphatic group, a divalent aromatic group or a divalent heterocyclic group, an alkylene group which may have a substituent having 1 to 5 carbon atoms, or a phenylene group. ,
It is more preferable that it is an alkylene group which may have a substituent having 1 to 5 carbon atoms or a phenylene group, and an alkylene which may have a substituent having 1 to 5 carbon atoms. More preferably, it is a group, and even more preferably an ethylene group.
The preferred ranges of the divalent aliphatic group, divalent aromatic group and divalent heterocyclic group in L ¹ and L ² are the divalent aliphatic group and divalent aromatic group in L. It is the same as the preferable range of the group and divalent heterocyclic group.

Preferred combinations of R ¹ and L in the general formula (1) or the general formula (2) is, R ¹ in the general formula (1) or (2) is a hydrogen atom or a methyl group, L is a divalent In this embodiment, the group is an aliphatic group, a divalent aromatic group, -C (= O)-, or -L ¹ -L ^2- .
More preferably, R ¹ in the general formula (1) or (2) is a hydrogen atom or a methyl group, and L is L ¹ -L ^2- .
Particularly preferably, R ¹ is a hydrogen atom or a methyl group, L ¹ is —C (═O) —O—, and L ² is an alkylene group optionally having a substituent having 1 to 5 carbon atoms. This is an embodiment.
More particularly preferred is an embodiment in which R ¹ is a hydrogen atom or a methyl group, L ¹ is —C (═O) —O—, and L ² is an ethylene group. That is, an embodiment in which the ethylenically unsaturated monomer represented by the general formula (1) is ethyl acetoacetate methacrylate or ethyl acetoacetate is more preferable.
Furthermore, an embodiment in which R ¹ in the general formula (1) or (2) is a methyl group is even more preferable. That is, the ethylenically unsaturated monomer represented by the general formula (1) is ethyl acetoacetate. Even more particularly preferred.

R ² represents a hydrogen atom or an alkyl group.
R ² is preferably independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom.

Although the monomer component which can comprise the polymer which has the said specific (beta) -ketoester structure useful for this invention is given to the following, this invention is not limited to these specific examples.

The ethylenically unsaturated monomers represented by the general formula (1) can be used alone or in combination of two or more, and particularly preferably ethyl acetoacetate methacrylate, ethyl acetoacetate or a mixture thereof.
Here, when using in combination of 2 or more types of ethylenically unsaturated monomers represented by the said General formula (1), the polymer which has the said specific (beta) -ketoester structure obtained becomes a copolymer of those monomers. That is, the polymer having the specific β-ketoester structure may be a homopolymer of only one ethylenically unsaturated monomer represented by the general formula (1), and is represented by the general formula (1). It may be a copolymer obtained using a combination of two ethylenically unsaturated monomers. There is no particular limitation on the composition ratio of the repeating units corresponding to the monomers of the copolymer obtained by combining two types of ethylenically unsaturated monomers represented by the general formula (1).

  The ethylenically unsaturated monomer represented by the general formula (1) used in the present invention can be obtained as a commercial product or synthesized with reference to known literature.

(Other repeat units)
The polymer having the specific β-ketoester structure is a copolymer containing other repeating units in addition to the repeating unit derived from one or more ethylenically unsaturated monomers represented by the general formula (1). It may be.
Among them, in the present invention, the polymer having the specific β-ketoester structure is a copolymer of the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylenically unsaturated monomer. It is preferable that it is a polymer obtained by making it. Furthermore, among them, the present invention exhibits a more preferable effect when an acrylic polymer or vinyl polymer that has a high haze when blended with cellulose acylate has been preferably used as a conventional additive. Specifically, when it is desired to exhibit the performance of conventional high molecular weight additives such as acrylic polymers and vinyl polymers, the repeating unit derived from the ethylenically unsaturated monomer represented by the general formula (1) and its unit By copolymerizing the repeating units of such additives, high transparency can be achieved even at molecular weights and mixing ratios in which transparency is impaired by conventional high molecular weight additives such as acrylic polymers and vinyl polymers. In addition, it is possible to provide a cellulose acylate film having a moisture content equal to or lower than that of conventional additives such as acrylic polymers and vinyl polymers. That is, as a result of being able to widen the design range of high molecular weight additives so as to achieve both high transparency and low water content that could not be achieved by conventional high molecular weight additives, according to the present invention. A cellulose acylate film having a low moisture content and excellent transparency can be provided.
Hereinafter, a preferred embodiment of the present invention, an embodiment of a polymer obtained by copolymerizing repeating units derived from one or more ethylenically unsaturated monomers represented by the general formula (1) will be described.

  Moreover, there is no restriction | limiting in particular as a monomer for comprising the said other repeating unit, However, It is preferable that it is an ethylenically unsaturated monomer. Examples of the ethylenically unsaturated monomer copolymerizable with the ethylenically unsaturated monomer represented by the general formula (1) include the ethylenically unsaturated monomer represented by the general formula (1). Other ethylenically unsaturated monomers other than the ethylenically unsaturated monomer represented by formula (1) may be used, but other ethylenically unsaturated monomers other than the ethylenically unsaturated monomer represented by the general formula (1) are preferred.

Examples of other ethylenically unsaturated monomers other than the ethylenically unsaturated monomer represented by the general formula (1) include methacrylic acid and ester derivatives thereof (methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate). Methacrylic acid i
-Butyl, t-butyl methacrylate, octyl methacrylate, cyclohexyl methacrylate, adamantyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, methacryl Dimethylaminoethyl acid, diethylaminoethyl methacrylate, etc.), acrylic acid and its ester derivatives (methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, i-butyl acrylate, acrylic acid t
-Butyl, octyl acrylate, cyclohexyl acrylate, adamantyl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, dimethylaminoethyl acrylate Diethylaminoethyl, etc.), alkyl vinyl ether (methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, etc.), alkyl vinyl ester (vinyl formate, vinyl acetate, vinyl butyrate, vinyl caproate, vinyl stearate), styrene derivatives (styrene, α-methylstyrene) , O-methylstyrene, m-methylstyrene, p-methylstyrene, etc.), crotonic acid, maleic acid, fumaric acid, itaconic acid, acrylonitrile, methacrylic acid Nitrile, fumaronitrile, vinyl chloride, vinylidene chloride, acrylamide, methacrylamide, acryloyl morpholine, methacryloyl morpholine, vinyl pyrrolidone, vinyl carbazole, vinyl ketones, mention may be made of unsaturated compounds such as vinyl pyridine.
These can be copolymerized with the ethylenically unsaturated monomer represented by the general formula (1) alone or in combination of two or more.

  Among these ethylenically unsaturated monomers other than the ethylenically unsaturated monomer represented by the general formula (1), acrylic acid ester, methacrylic acid ester, acrylonitrile, methacrylonitrile, acryloylmorpholine, methacryloylmorpholine, acrylamide , Preferably at least one selected from the group consisting of methacrylamide. Here, the (meth) acrylic acid ester as another ethylenically unsaturated monomer other than the ethylenically unsaturated monomer represented by the general formula (1) is methyl (meth) acrylate, (meth) acrylic acid. 2-hydroxyethyl, t-butyl (meth) acrylate, adamantyl (meth) acrylate, and isobornyl (meth) acrylate, more preferably methyl (meth) acrylate, and methyl methacrylate It is particularly preferred.

(Definition of molecular weight of a polymer having a specific β-ketoester structure)
The weight average molecular weight of the polymer having the specific β-ketoester structure used in the present invention is preferably 500 to 300,000, particularly preferably more than 110,000 and 300,000. From the viewpoint of obtaining a uniform film having no planar defects, the weight average molecular weight of the polymer having the specific β-ketoester structure is more preferably 100,000 to 300,000.

  The number average molecular weight of the polymer having the specific β-ketoester structure is preferably 200 to 200,000, more preferably 2000 to 100,000, and particularly preferably 10,000 to 60,000.

(Definition of composition ratio of polymer having specific β-ketoester structure)
The content of the structural unit derived from the ethylenically unsaturated monomer represented by the general formula (1) in the whole polymer having the specific β-ketoester structure is preferably 0.1 to 100 mol%. More preferably, it is -100 mol%.

(Synthesis method of the polymer having the specific β-ketoester structure)
Although the method for polymerizing the polymer having the specific β-ketoester structure in the present invention is not particularly limited, conventionally known methods can be widely employed, and examples thereof include radical polymerization, anionic polymerization, and cationic polymerization. Examples of the initiator for the radical polymerization method include azo compounds and peroxides, and examples thereof include azobisisobutyronitrile (AIBN), azoisobutyric acid diester derivatives, and benzoyl peroxide. The polymerization solvent is not particularly limited. For example, aromatic hydrocarbon solvents such as toluene and chlorobenzene, halogenated hydrocarbon solvents such as dichloroethane and chloroform, ether solvents such as tetrahydrofuran and dioxane, and amide solvents such as dimethylformamide. And alcohol solvents such as methanol, ester solvents such as methyl acetate and ethyl acetate, ketone solvents such as acetone, cyclohexanone and methyl ethyl ketone, and water solvents. Depending on the selection of the solvent, solvent polymerization that polymerizes in a homogeneous system, precipitation polymerization that precipitates the produced polymer, and emulsion polymerization that polymerizes in a micelle state can also be performed.

(Addition amount of the polymer having the specific β-ketoester structure)
Polymer having the specific β- ketoester structure preferably be mixed at a ratio of 1 to 150 parts by mass with respect to 100 parts by weight of cellulose acylate, more preferably preferably be mixed with 5 to 100 parts by mass.
From the viewpoint of obtaining a uniform film having no planar defects, the polymer having the specific β-ketoester structure is particularly preferably mixed at 20 to 100 parts by mass with respect to 100 parts by mass of cellulose acylate, and 30 to 80 It is more particularly preferable to mix at a part by mass.

  Next, components other than the polymer having the specific β-ketoester structure in a cellulose acylate film that can be used for a retardation film, a polarizing plate and the like will be described in detail.

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

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

  Cellulose acylate raw material cellulose used in the present invention includes cotton linter and wood pulp (hardwood pulp, softwood pulp), etc., and any cellulose acylate obtained from any raw material cellulose can be used, optionally mixed. May be. Detailed descriptions of these raw material celluloses can be found in, for example, “Plastic Materials Course (17) Fibrous Resin” (Marusawa, Uda, Nikkan Kogyo Shimbun, published in 1970) and Invention Association Publication Technical Report 2001-1745 ( 7 to 8) can be used, and the cellulose acylate film of the present invention is not particularly limited.

Next, the cellulose acylate suitable for the present invention produced from the above-mentioned cellulose will be described.
The cellulose acylate used in the present invention is one in which the hydroxyl group of cellulose is acylated, and the substituent can be any acetyl group having 2 carbon atoms to 22 carbon atoms. In the present invention, the degree of substitution of the cellulose acylate with the hydroxyl group of cellulose is not particularly limited, but the degree of substitution is calculated by measuring the degree of binding of acetic acid and / or a fatty acid having 3 to 22 carbon atoms substituted for the hydroxyl group of cellulose. Can be obtained. As a measuring method, it can carry out according to ASTM D-817-91.

  As described above, the substitution degree of cellulose with a hydroxyl group is not particularly limited, but the acyl substitution degree of cellulose with a hydroxyl group is preferably 1.50 to 3.00.

  Among the acetic acid substituted for the hydroxyl group of cellulose and / or the fatty acid having 3 to 22 carbon atoms, the acyl group having 2 to 22 carbon atoms may be an aliphatic group or an aryl group, and is not particularly limited. A mixture of They are, for example, alkyl carbonyl esters, alkenyl carbonyl esters, aromatic carbonyl esters, or aromatic alkyl carbonyl esters of cellulose, each of which may further have a substituted group. These preferred acyl groups include acetyl, propionyl, butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, i-butanoyl, t-butanoyl, cyclohexanecarbonyl, Examples include oleoyl, benzoyl, naphthylcarbonyl, and cinnamoyl groups. Among these, acetyl, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl and the like are preferable, and acetyl, propionyl and butanoyl are more preferable. The most preferred group is acetyl.

  Among the acetic acid substituted for the hydroxyl group of cellulose and / or the fatty acid having 3 to 22 carbon atoms, the acyl group having 2 to 22 carbon atoms may be an aliphatic group or an aryl group, and is not particularly limited. A mixture of They are, for example, alkyl carbonyl esters, alkenyl carbonyl esters, aromatic carbonyl esters, or aromatic alkyl carbonyl esters of cellulose, each of which may further have a substituted group. These preferred acyl groups include acetyl, propionyl, butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, i-butanoyl, t-butanoyl, cyclohexanecarbonyl, Examples include oleoyl, benzoyl, naphthylcarbonyl, and cinnamoyl groups. Among these, acetyl, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl and the like are preferable, and acetyl, propionyl and butanoyl are more preferable. The most preferred group is acetyl.

Among the acyl substituents substituted on the hydroxyl group of the cellulose, when it is substantially composed of at least two kinds of acetyl group / propionyl group / butanoyl group, the total substitution degree is 1.50 to 3.00. The acyl substitution degree is more preferably 1.80 to 2.95. In the case where the acyl substituent of the cellulose acylate is composed only of an acetyl group, the total substitution degree is preferably 2.00 to 3.00. Furthermore, the substitution degree is more preferably 2.40 to 2.95.
In the present invention, by combining with the polymer having the specific β-ketoester structure, the water content of the cellulose acylate film can be greatly reduced and high transparency can be obtained. In particular, the same effect can be obtained even when cellulose acylate having a low total acyl substitution degree is used.

  The degree of polymerization of cellulose acylate preferably used in the present invention is 180 to 700 in terms of viscosity average polymerization degree, and in cellulose acetate, 180 to 550 is more preferable, 180 to 400 is more preferable, and 180 to 350 is particularly preferable. . If the degree of polymerization is not more than the upper limit, the viscosity of the cellulose acylate dope solution does not become too high, and a film can be easily produced by casting. If the degree of polymerization is equal to or greater than the lower limit, it is preferable because there is no inconvenience such as a decrease in strength of the produced film. The viscosity average degree of polymerization can be measured by Uda et al.'S intrinsic viscosity method {Kazuo Uda, Hideo Saito, "Journal of the Textile Society," Vol. 18, No. 1, pages 105-120 (1962)}. This method is also described in detail in JP-A-9-95538.

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

<Method for producing cellulose acylate film>
The cellulose acylate film of the present invention can be produced by a solvent cast method. In the solvent cast method, a film is produced using a solution (dope) in which cellulose acylate is dissolved in an organic solvent.
The organic solvent is 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. It is preferable to contain.
The ether, ketone and ester may have a cyclic structure. A compound having two or more functional groups of ether, ketone and ester (that is, —O—, —CO— and —COO—) can also be used as the organic solvent. The organic solvent may have another functional group such as an alcoholic hydroxyl group. In the case of an organic solvent having two or more types of functional groups, the number of carbon atoms is preferably within the above-described preferable range of carbon atoms of the solvent having any functional group.

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

A cellulose acylate solution can be prepared by a general method comprising processing at a temperature of 0 ° C. or higher (ordinary temperature or high temperature). The solution can be prepared using a dope preparation method and apparatus in a normal solvent cast method. In the case of a general method, it is preferable to use a halogenated hydrocarbon (particularly methylene chloride) as the organic solvent.
The amount of cellulose acylate is adjusted so as to be contained in the obtained solution in an amount of 10 to 40% by mass. The amount of cellulose acylate is more preferably 10 to 30% by mass. Arbitrary additives described later may be added to the organic solvent (main solvent).
The solution can be prepared by stirring the cellulose acylate and the organic solvent at room temperature (0 to 40 ° C.). High concentration solutions may be stirred under pressure and heating conditions. Specifically, cellulose acetate and an organic solvent are placed in a pressure vessel and sealed, and stirred while heating to a temperature not lower than the boiling point of the solvent at normal temperature and in a range where the solvent does not boil.
The heating temperature is usually 40 ° C. or higher, preferably 60 to 200 ° C., and more preferably 80 to 110 ° C.

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

A cellulose acylate film is produced from the prepared cellulose acylate solution (dope) by a solvent cast method.
The dope is cast on a drum or band and the solvent is evaporated to form a film. The concentration of the dope before casting is preferably adjusted so that the solid content is 16 to 35%. The surface of the drum or band is preferably finished in a mirror state. The dope is preferably cast on a drum or band having a surface temperature of 10 ° C. or less.

In the present invention, when the dope (cellulose acylate solution) is cast on the band, it is substantially 10 seconds to 90 seconds, preferably 15 seconds to 90 seconds in the first half of the drying before peeling, and substantially no wind. The process of drying is performed. Further, when casting on a drum, it is preferable to perform a step of drying in a substantially windless manner for a period of 1 second to 10 seconds, preferably 2 seconds to 5 seconds, in the first half of drying before peeling.
In the present invention, “drying before stripping” refers to drying from when a dope is applied on a band or drum until stripping as a film. In addition, the “first half” refers to a process before half of the total time required from dope application to stripping. “Substantially no wind” means that a wind speed of 0.5 m / s or more is not detected at a distance within 200 mm from the band surface or drum surface (the wind speed is less than 0.5 m / s).
The first half of the pre-peeling drying is usually about 30 to 300 seconds on the band, but is dried for 10 to 90 seconds, preferably 15 to 90 seconds, without wind. When it is on the drum, it is usually about 5 to 30 seconds, but it is dried without wind for 1 to 10 seconds, preferably 2 to 5 seconds. The ambient temperature is preferably 0 ° C to 180 ° C, more preferably 40 ° C to 150 ° C. The operation of drying without wind can be carried out at any stage in the first half of the drying before peeling, but it is preferably carried out immediately after casting. When the time for drying without wind is less than 10 seconds on the band (less than 1 second on the drum), it is difficult for the additive to be uniformly distributed in the film, and when it exceeds 90 seconds (drum In the above case, if it exceeds 10 seconds), the film will be peeled off due to insufficient drying, and the surface condition of the film will deteriorate.
Drying can be performed by blowing an inert gas during the time other than drying with no wind in drying before peeling. The air temperature at this time is preferably 0 ° C to 180 ° C, more preferably 40 ° C to 150 ° C.

  As for the drying method in the solvent casting method, U.S. Pat. Nos. 2,336,310, 2,367,603, 2,429,078, 2,429,297, 2,429,978, 2,607,704, 2,739,69, 2,739,070, British Patents 6,407,331, 7,36892 Nos. 45-4554, 49-5614, JP-A-60-176834, JP-A-60-203430, and JP-A-62-115035. Drying on the band or drum can be performed by blowing an inert gas such as air or nitrogen.

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

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

<Additives>
A degradation inhibitor (eg, antioxidant, peroxide decomposer, radical inhibitor, metal deactivator, acid scavenger, amine) may be added to the cellulose acylate film. The deterioration preventing agents are described in JP-A-3-199201, JP-A-5-194789, JP-A-5-271471, and JP-A-6-107854. The addition amount of the deterioration preventing agent is 0.01 to 1% by mass of the solution (dope) to be prepared from the viewpoint of manifesting the effect and suppressing the bleeding out of the deterioration preventing agent to the film surface. Preferably, it is 0.01-0.2 mass%.
Examples of particularly preferred deterioration inhibitors include butylated hydroxytoluene (BHT) and tribenzylamine (TBA).

An ultraviolet absorber may be added to the cellulose acylate film of the present invention. As the ultraviolet absorber, compounds described in JP-A-2006-282929 (benzophenone, benzotriazole, triazine) are preferably used. Two or more ultraviolet absorbers can be used in combination.
Benzotriazole is preferable as the ultraviolet absorber, and specific examples include TINUVIN 328, TINUVIN 326, TINUVIN 329, TINUVIN 571, ADK STAB LA-31, and the like.
The amount of the ultraviolet absorber used is preferably 10% or less, more preferably 3% or less, and most preferably 2% or less and 0.05% or more with respect to the cellulose acylate.

(Matting agent fine particles)
The cellulose acylate 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 and calcium phosphate. be able to. Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable. The fine particles of silicon dioxide preferably have a primary average particle size of 20 nm or less and an apparent specific gravity of 70 g / L or more. Those having an average primary particle size as small as 5 to 16 nm are more preferred because they can reduce the haze of the film. The apparent specific gravity is preferably 90 to 200 g / L, more preferably 100 to 200 g / L. A larger apparent specific gravity is preferable because a high-concentration dispersion can be produced, and haze and aggregates are improved. A desirable embodiment is described in detail in pages 35 to 36 of the Japan Institute of Invention and Technology (Publication No. 2001-1745, published on March 15, 2001, Japan Society of Invention), and in the cellulose acylate film of the present invention. Can also be preferably used.

(Stretching)
In the cellulose acylate film of the present invention, the retardation can be adjusted by a stretching treatment. For example, JP-A-62-115035, JP-A-4-152125, JP-A-4-284111, and JP-A-4-298310 can be used for positively stretching in the width direction (perpendicular to the conveying direction). And JP-A-11-48271. The film is stretched at room temperature or under heating conditions. The heating temperature is preferably ± 20 ° C. sandwiching the glass transition temperature of the film. If the film is stretched at a temperature extremely lower than the glass transition temperature, it tends to break and cannot exhibit desired optical properties. In addition, when stretching at a temperature extremely higher than the glass transition temperature, it is not possible to fix the orientation by relaxing with the heat during stretching before the molecularly oriented material by stretching is heat-set. Becomes worse.

  Further, in the stretching zone (for example, the tenter zone), a zone for normal relaxation is provided after the film is bitten and transported and passed through the maximum widening rate. This is the zone necessary to reduce axial misalignment. In the normal stretching, in the relaxation rate zone after passing through this maximum widening rate, the time until it passes through the tenter zone is shorter than 1 minute, and the film may be stretched uniaxially only in the transport direction or width direction, or simultaneously or sequentially. Although biaxial stretching may be used, it is preferable to stretch more in the width direction. Stretching in the width direction is preferably 5 to 100%, particularly preferably 5 to 80%. In addition, the stretching process may be performed in the middle of the film forming process, or the raw film that has been formed and wound may be stretched. In the former case, stretching may be performed in a state including the residual solvent amount, and the residual solvent amount = (residual volatile matter mass / heat-treated film mass) × 100% is preferably stretched at 0.05 to 50%. be able to. It is particularly preferable to perform 5 to 80% stretching in a state where the residual solvent amount is 0.05 to 5%.

Further, the cellulose acylate film of the present invention may be biaxially stretched.
Biaxial stretching includes simultaneous biaxial stretching and sequential biaxial stretching, but sequential biaxial stretching is preferred from the viewpoint of continuous production, and after casting the dope, the film is peeled off from the band or drum, After stretching in the width direction, the film is stretched in the longitudinal direction or stretched in the longitudinal direction and then stretched in the width direction.

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

(Surface treatment of cellulose acylate film)
The cellulose acylate film is preferably subjected to a surface treatment. Specific examples include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment, and ultraviolet irradiation treatment. It is also preferable to provide an undercoat layer as described in JP-A-7-333433.
From the viewpoint of maintaining the flatness of the film, in these treatments, the temperature of the cellulose acylate film is preferably 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 acid treatment or alkali treatment, that is, saponification treatment for cellulose acylate, from the viewpoint of adhesiveness with a polarizer.
The surface energy is preferably 55 mN / m or more, and more preferably 60 mN / m or more and 75 mN / m or less.

Hereinafter, the alkali saponification treatment will be specifically described as an example.
The alkali saponification treatment of the cellulose acylate film is preferably performed in a cycle in which the film surface is immersed in an alkali solution, neutralized with an acidic solution, washed with water and dried.
Examples of the alkaline solution include potassium hydroxide solution and sodium hydroxide solution, and the hydroxide ion concentration is preferably in the range of 0.1 to 3.0 mol / liter, 0.5 to 2.0 mol / liter. More preferably, it is in the range of liters. The alkaline solution temperature is preferably in the range of room temperature to 90 ° C, more preferably in the range of 40 to 70 ° C.

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

<Characteristics of cellulose acylate film>
The cellulose acylate film of the present invention is excellent in transparency, and when used for a protective film or a retardation film, a liquid crystal display device showing high contrast can be provided. In a more preferred embodiment of the cellulose acylate film of the present invention containing a high molecular weight polymer, planar defects are reduced and display unevenness can be reduced.
Hereinafter, the characteristics of the cellulose acylate film of the present invention will be described together with other preferable characteristics.

(Haze of film)
The haze of the cellulose acylate film of the present invention is preferably 1% or less, more preferably 0.01 to 1.0%, and particularly preferably 0.01 to 0.5%. By setting the haze to 0.5% or less, the contrast ratio when incorporated in a liquid crystal display device can be improved. In addition, there is an advantage that the transparency of the film becomes higher and it is easier to use as an optical film.
In the present invention, haze is obtained in accordance with JIS K-6714 using a haze meter “HGM-2DP” (manufactured by Suga Test Instruments Co., Ltd.) at 25 ° C. and 60% RH at a cellulose acylate film sample of 40 mm × 80 mm of the present invention. The measured value was used.

(Equilibrium moisture content of film)
The equilibrium moisture content of the cellulose acylate film of the present invention is 25 ° C., regardless of the film thickness, so as not to impair the adhesion with a water-soluble polymer such as polyvinyl alcohol when used as a protective film of a polarizing plate. The equilibrium water content at a relative humidity of 80% is preferably 0 to 4%. It is more preferably 0.1 to 3.5%, and particularly preferably 1 to 3%. If the equilibrium moisture content is 4% or less, it is preferable that the dependency of retardation due to humidity change does not become too large when used as a support for an optical compensation film.
In the present invention, the moisture content is determined by curling the cellulose acylate film sample 7 mm × 35 mm of the present invention with a moisture measuring device and sample drying apparatuses “CA-03” and “VA-05” (both manufactured by Mitsubishi Chemical Corporation). A value calculated by measuring by the Fisher method and dividing the amount of water (g) by the sample mass (g) was used.

(Surface defects)
In the present invention, a planar defect is a streak-like planar defect extending along the longitudinal direction of the wound film, or a stripe-like surface extending elongated along the width direction of the film. It refers to step unevenness that is a surface defect, a streaky surface defect that intersects the longitudinal direction and the width direction, and a wind unevenness that is a surface defect other than a streak. In a preferred embodiment of the cellulose acylate film of the present invention, planar defects can be further improved.

(Width Length)
The preferred width of the cellulose acylate film of the present invention is 0.1 to 5 m, more preferably 0.1 to 3 m. The preferable winding length of a film is 300-30000m, More preferably, it is 500-10000m, More preferably, it is 1000-7000m.

(Film thickness)
The film thickness of the cellulose acylate film of the present invention is preferably 20 μm to 180 μm, more preferably 30 μm to 120 μm, and even more preferably 40 μm to 100 μm. A film thickness of 20 μm or more is preferable in terms of handling properties when processing into a polarizing plate or the like and curling suppression of the polarizing plate. Further, the film thickness unevenness of the cellulose acylate film of the present invention is preferably 0 to 2% in both the transport direction and the width direction, more preferably 0 to 1.5%, and 0 to 1%. Is particularly preferred.

(Configuration of cellulose acylate film)
The cellulose acylate film of the present invention may have a single layer structure or a plurality of layers, but preferably has a single layer structure. Here, the “single layer structure” film does not mean that a plurality of film materials are bonded together, but means a single cellulose acylate film. And the case where one sheet of a cellulose acylate film is produced from a plurality of cellulose acylate solutions using a sequential casting method or a co-casting method is included.

  In this case, a cellulose acylate film having a distribution in the thickness direction can be obtained by appropriately adjusting the type and blending amount of additives, the molecular weight distribution of cellulose acylate, the type of cellulose acylate, and the like. Moreover, what has various functional parts, such as an optical anisotropy part, a glare-proof part, a gas barrier part, and a moisture-resistant part, in those one film is also included.

(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. Here, the polarizing plate of the present invention described later preferably includes a functional layer, but the film of the present invention is incorporated into the polarizing plate of the present invention even if the film of the present invention has a functional layer. Sometimes other functional films may be stacked.
The functional layer is not particularly limited as long as it is not contrary to the gist of the present invention, and examples thereof include the following functional layers. Among them, when the film of the present invention is used as a base film, it is particularly preferable to form a hard coat layer directly on it, and the hard coat layer is preferably installed 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

(Retardation film)
The cellulose acylate film of the present invention can be used as a retardation film. The “retardation film” is generally used for a display device such as a liquid crystal display device, and means an optical material having optical anisotropy, and is synonymous with a retardation plate, an optical compensation film, an optical compensation sheet, and the like. It is. In a liquid crystal display device, a retardation film is used for the purpose of improving the contrast of a display screen or improving viewing angle characteristics and color.
By using the transparent cellulose acylate film of the present invention, a retardation film in which the Re value and the Rth value are freely controlled can be easily produced.

  In addition, a plurality of the cellulose acylate films of the present invention are laminated, or the cellulose acylate film of the present invention and a film other than the present invention are laminated, and Re and Rth are appropriately adjusted and used as a retardation film. You can also. Lamination of the film can be performed using a pressure-sensitive adhesive or an adhesive.

In some cases, the cellulose acylate 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 provided thereon to be used as a retardation film. The optically anisotropic layer applied to the retardation film of the present invention may be formed from, for example, a composition containing a liquid crystal compound, or may be formed from a cellulose acylate film having birefringence. The cellulose acylate film of the present invention may be used.
The liquid crystal compound is preferably a discotic liquid crystal compound or a rod-like liquid crystal compound.

[Polarizer]
The cellulose acylate film of the present invention can be used as a protective film for a polarizing plate (the polarizing plate of the present invention). The polarizing plate of the present invention has a polarizer and two polarizing plate protective films (transparent films) that protect the polarizer and both surfaces thereof, and at least one of the protective films is the cellulose acylate of the present invention. It is a film.
When the cellulose acylate film of the present invention is used as the polarizing plate protective film, the cellulose acylate film of the present invention is subjected to the surface treatment (also described in JP-A Nos. 6-94915 and 6-118232). For example, glow discharge treatment, corona discharge treatment, or alkali saponification treatment is preferably performed. In particular, when the cellulose acylate constituting the cellulose acylate film of the present invention is cellulose acylate, an alkali saponification treatment is most preferably used as the surface treatment.

  As the polarizer, for example, a film obtained by immersing and stretching a polyvinyl alcohol film in an iodine solution can be used. When using a polarizer obtained by immersing and stretching a polyvinyl alcohol film in an iodine solution, the surface-treated surface of the transparent cellulose acylate 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 acylate film is directly bonded to the polarizer as described above. As the adhesive, an aqueous solution of polyvinyl alcohol or polyvinyl acetal (for example, polyvinyl butyral) or a latex of vinyl polymer (for example, polybutyl acrylate) can be used. A particularly preferred adhesive is an aqueous solution of fully saponified polyvinyl alcohol.

  In general, a liquid crystal display device includes four polarizing plate protective films because a liquid crystal cell is provided between two polarizing plates. The cellulose acylate film of the present invention may be used for any of the four polarizing plate protective films, but the cellulose acylate film of the present invention is interposed between the polarizer and the liquid crystal layer (liquid crystal cell) in the liquid crystal display device. As the protective film to be arranged, it can be used particularly advantageously. Further, the protective film disposed on the opposite side of the cellulose acylate film of the present invention with the polarizer interposed therebetween can be provided with a transparent hard coat layer, an antiglare layer, an antireflection layer, and the like, particularly a liquid crystal display device. It is preferably used as a polarizing plate protective film on the outermost surface of the display side.

[Liquid Crystal Display]
The liquid crystal display device of the present invention is a liquid crystal display device having a liquid crystal cell and a pair of polarizing plates disposed on both sides of the liquid crystal cell, wherein at least one of the polarizing plates is the polarizing plate of the present invention. To do.
The cellulose acylate film and polarizing plate of the present invention can be used for liquid crystal display devices in various display modes.
Each liquid crystal mode in which these films are used will be described below. Among these modes, the cellulose acylate film, retardation film and polarizing plate of the present invention are particularly preferably used for VA mode and IPS mode liquid crystal display devices. These liquid crystal display devices may be any of a transmissive type, a reflective type, and a transflective type.

(TN type liquid crystal display device)
The cellulose acylate film of the present invention may be used as a support for a retardation film of a TN liquid crystal display device having a TN mode liquid crystal cell. TN mode liquid crystal cells and TN type liquid crystal display devices have been well known for a long time. Regarding the retardation film used in the TN type liquid crystal display device, each of JP-A-3-9325, JP-A-6-148429, JP-A-8-50206, and JP-A-9-26572, and Mori. Other papers (Jpn. J. Appl. Phys. Vol. 36 (1997) p. 143 and Jpn. J. Appl. Phys. Vol. 36 (1997) p. 1068) are described.

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

(IPS liquid crystal display device and ECB liquid crystal display device)
The cellulose acylate film of the present invention is particularly used as a retardation film, a retardation film support or a protective film for a polarizing plate of an IPS liquid crystal display device and an ECB liquid crystal display device having IPS mode and ECB mode liquid crystal cells. It is advantageously used. In these modes, the liquid crystal material is aligned substantially in parallel during black display, and black is displayed by aligning liquid crystal molecules in parallel with the substrate surface in the absence of applied voltage. In these embodiments, the polarizing plate using the cellulose acylate film of the present invention contributes to widening the viewing angle and improving the contrast.

(Reflective liquid crystal display)
The cellulose acylate film of the present invention is also advantageously used as a retardation film of a reflective liquid crystal display device of TN type, STN type, HAN type, and GH (Guest-Host) type. These display modes have been well known since ancient times. The TN-type reflective liquid crystal display device is described in JP-A-10-123478, WO98 / 48320 pamphlet, and Japanese Patent No. 3022477. The retardation film used in the reflective liquid crystal display device is described in International Publication No. 00/65384 pamphlet.

(Other liquid crystal display devices)
The cellulose acylate 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 (Axial Symmetrical Microcell) mode. The ASM mode liquid crystal cell is characterized in that the thickness of the cell is maintained by a resin spacer whose position can be adjusted. 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]
In some cases, the cellulose acylate film of the present invention may be applied to a hard coat film, an antiglare film, and an antireflection film. For the purpose of improving the visibility of flat panel displays such as LCD, PDP, CRT, EL, etc., any or all of a hard coat layer, an antiglare layer and an antireflection layer on one or both sides of the transparent cellulose acylate film of the present invention Can be granted. Preferred embodiments of such an antiglare film and antireflection film are described in detail on pages 54 to 57 of the Japan Society for Invention and Innovation (Publication No. 2001-1745, published on March 15, 2001, Japan Society of Invention and Innovation). It can be preferably used also in the cellulose acylate film of the present invention.

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

<Synthesis Example 1>
(Synthesis of a polymer having a specific β-ketoester structure)
Into a 300 ml three-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 20.0 g of methyl ethyl ketone was charged and heated to 80 ° C. Next, a mixed solution consisting of 40.0 g of ethyl acetoacetate (A-1), 20.0 g of methyl ethyl ketone, and 0.40 g of azo polymerization initiator “V-601” (manufactured by Wako Pure Chemical Industries, Ltd.) was added for 3 hours. Was dropped at a constant speed so that the dropping was completed. After completion of the dropwise addition, the mixture was stirred for 1 hour, (1) a solution consisting of 0.10 g of “V-601” and 1.0 g of methyl ethyl ketone was added, and the mixture was stirred for 2 hours. Subsequently, the step (1) was repeated twice, and stirring was further continued for 2 hours, followed by pouring into 1.5 liters of n-hexane and drying to obtain 39.5 g of ethyl acetoacetate polymer. The polymer having the specific β-ketoester structure has a weight average molecular weight (Mw) of 38300 (calculated in terms of polystyrene by gel permeation chromatography (GPC), and the columns used are TSKgel SuperHZM-H, TSKgel SuperHZ4000, TSKgel SuperHZ200 (Tosoh Corporation). Made)).

<Comparative Synthesis Example 1>
(Synthesis of comparative polymer)
In the said synthesis example 1, the methyl methacrylate polymer was synthesize | combined like the synthesis example 1 except having changed into the methyl methacrylate (B-1) instead of the ethyl acetoacetate.

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

Composition of cellulose acylate solution: 100 parts by mass of cellulose acylate (acetyl substitution degree: 2.85) 11 parts by mass of polymer synthesized in Synthesis Example 1 457 parts by mass of methylene chloride, 68 parts by mass of methanol

(Preparation of cellulose acylate film)
The obtained dope was cast on a glass plate. The temperature on the glass plate was set to 14-18 ° C.
After casting, the glassy web was dried at 70 ° C. for 6 minutes, and then the cellulose acylate film was peeled off and sandwiched between clips.

  The film thickness of the obtained cellulose acylate film was 60 μm. This film was used as the cellulose acylate film of Example 1.

[Examples 2-34 and Comparative Examples 1-7]
A film was prepared in the same manner as in Example 1 except that the type of cellulose acylate, the type of polymer, and the amount added were changed as shown in Table 1 below. Examples 2 to 34 and Comparative Example 1 were used, respectively. A cellulose acylate film of ˜7 was obtained.
The structures A-1, A-2, B-1 to B-4 of the ethylenically unsaturated monomers in the respective comparative examples and examples are shown below. In the case where the polymer is a copolymer, each copolymer having a monomer composition ratio shown in Table 1 was produced in the same manner except that two monomers were used in the method described in Synthesis Example 1. .

[Evaluation]
(Measurement of moisture content)
The resulting cellulose acylate films of each Example and Comparative Example were conditioned for 24 hours in an environment of 25 ° C. and 80% relative humidity, and then the equilibrium moisture content was measured using an AQ-2000 Karl Fischer moisture measuring device manufactured by Hiranuma Sangyo Co., Ltd. It was measured.
The obtained results are shown in Table 1 below.

(Measure haze)
The obtained cellulose acylate film samples 40 mm × 80 mm of each Example and Comparative Example were measured according to JIS K-6714 with a haze meter (HGM-2DP, Suga Test Instruments) in an environment of 25% relative humidity 60%. .
The obtained results are shown in Table 1 below.

(Surface defects)
Spread the cellulose acylate films of each of the Examples and Comparative Examples obtained on a flat table covered with a black cloth, reflect the light of the fluorescent lamp with the film, and visually observe the flatness according to the following criteria. evaluated. The evaluation results are shown in Table 1.
(Double-circle): A planar defect is not confirmed at all but is very good.
○: Slightly confirmed but good.
Δ: Although confirmed, there is no practical problem and good.
X: Practically problematic.

From the results of Table 1 above, it was found that the cellulose acylate film to which the polymer having a specific β-ketoester structure of the present invention was added had a low moisture content, a low haze (high transparency), and was preferable.
Further, in a part of the system to which a polymer having a specific β-ketoester structure having a weight average molecular weight of 100,000 or more was added, no planar defects were confirmed, and a particularly uniform film could be obtained.

[Example 101]
<Manufacture of cellulose acylate film by manufacturing machine>
(Preparation of cellulose acylate solution C-1)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acylate solution C-1.

Composition of Cellulose Acylate Solution C-1 Cellulose acylate (acetyl substitution degree 2.85) 100 parts by mass Polymer 11 synthesized in Synthesis Example 1 11 parts by mass Methylene chloride 384 parts by mass Methanol 69 parts by mass Butanol 9 Parts by mass

(Preparation of matting agent dispersion D-1)
The following composition was charged into a disperser and stirred to dissolve each component to prepare a matting agent dispersion D-1.

Composition of matting agent dispersion D-1 Silica particle dispersion (average particle size 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 parts by mass-Cellulose acylate solution C-1 10.3 parts by mass

(Preparation of cellulose acylate film)
The cellulose acylate solution C-1 and the matting agent dispersion D-1 were sufficiently stirred while heating to dissolve each component, thereby preparing a dope. The obtained dope was heated to 30 ° C., and cast on a mirror surface stainless steel support, which was a drum having a diameter of 3 m, through a casting Giuser. The surface temperature of the support was set to −5 ° C., and the coating width was 1470 mm. The space temperature of the entire casting part was set to 15 ° C. Then, the cellulose acylate film that had been cast and rotated 50 cm before the end point of the casting part was peeled off from the drum, and then both ends were clipped with a pin tenter. The residual solvent amount of the cellulose ester web immediately after peeling was 70%, and the film surface temperature of the cellulose acylate web was 5 ° C.

  The cellulose acylate web held by the pin tenter was conveyed to the drying zone. In the initial drying, a drying air of 45 ° C. was blown. Next, it was dried at 110 ° C. for 5 minutes and further at 140 ° C. for 10 minutes. The film thickness of the obtained cellulose acylate film was 60 μm.

  The cellulose acylate film obtained in Example 101 was evaluated in the same manner as in Example 1. As a result, the haze, moisture content, and surface shape were as good as in Example 1.

<Manufacture of polarizing plate and liquid crystal display device>
[Saponification treatment of polarizing plate protective film]
The produced cellulose acylate film of Example 101 was immersed in a 2.3 mol / L sodium hydroxide aqueous solution at 55 ° C. for 3 minutes. It wash | cleaned in the room temperature water-washing bath, and neutralized using 0.05 mol / L sulfuric acid at 30 degreeC. Again, it was washed in a water bath at room temperature and further dried with hot air at 100 ° C. Thus, what performed the surface saponification process about the cellulose acylate film of Example 101 was used as the polarizing plate protective film of Example 101.

[Preparation of polarizing plate]
A polarizer was produced by adsorbing iodine to a stretched polyvinyl alcohol film.
The saponified polarizing plate protective film of Example 101 was attached to one side of the polarizer using a polyvinyl alcohol-based adhesive. A commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Film Co., Ltd.) was subjected to the same saponification treatment, and the side where the polarizing plate protective film of Example 101 prepared was pasted using a polyvinyl alcohol-based adhesive. A cellulose triacetate film after saponification treatment was attached to the surface of the opposite polarizer.
Under the present circumstances, it arrange | positioned so that the transmission axis of a polarizer and the slow axis of the polarizing plate protective film of the produced Example 101 may be orthogonally crossed. Further, the transmission axis of the polarizer and the slow axis of the commercially available cellulose triacetate film were also arranged so as to be orthogonal to each other.
Thus, the polarizing plate of Example 101 was produced.

[Examples 102 to 134 and Comparative Examples 101 to 107]
[Manufacture of cellulose acylate film by manufacturing machine, saponification treatment of polarizing plate protective film and production of polarizing plate]
A film was prepared in the same manner as in Example 101 except that the type of cellulose acylate, the type of polymer, and the amount added were changed as described in Table 1 above. Examples 102 to 134 and Comparative Example 101 were used, respectively. A cellulose acylate film of ~ 107 was obtained.
For the polarizing plate protective films of Examples 102 to 134 and the polarizing plate protective films of Comparative Examples 101 to 107, saponification treatment and production of polarizing plates were performed in the same manner as in Example 101. Examples 102 to 134 and Comparative Examples 101 to 107 polarizing plates were produced.

[Production and evaluation of liquid crystal display devices]
The polarizing plate on the viewer side of a commercially available liquid crystal television (BRAVIA J5000 from Sony Corporation) is peeled off, and the polarizing plate of the present invention using the polarizing plate protective film of Examples 101 to 134 is polarized in Examples 101 to 134. It stuck through the adhesive so that a board protective film might become a liquid crystal cell side. The transmission axis of the polarizing plate on the viewer side was arranged in the vertical direction. Moreover, the liquid crystal display device of the comparative example was produced similarly except having used the polarizing plate protective film of comparative examples 101-107 instead of the polarizing plate protective film of Examples 101-134. When the thus produced liquid crystal display device was allowed to stand for 24 hours in an environment of 60 ° C. and 90% relative humidity, display unevenness was confirmed. The liquid crystal display device of the present invention uses the polarizing plate protective film of each comparative example. The liquid crystal display device was preferable because no unevenness occurred or the unevenness generation area was small.

DESCRIPTION OF SYMBOLS 11 Polarizer 12 Polarizer 13 Liquid crystal cell 14 Cellulose acylate film 15 of each Example and Comparative Example Cellulose acylate film of each Example and Comparative Example

Claims (16)

Cellulose acylate,
A polymer obtained by polymerizing an ethylenically unsaturated monomer represented by the following general formula (1), or an ethylenically unsaturated monomer represented by the following general formula (1) and at least one other ethylenically unsaturated monomer cellulose acylate film characterized by containing a polymer obtained a monomer are copolymerized.
General formula (1)

(Wherein R ¹ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and the aliphatic group, aromatic group and heterocyclic group may have a substituent. Represents a bond, a divalent aliphatic group, a divalent aromatic group, a divalent heterocyclic group, —C (═O) —, —O—, —N (R ² ) —, or a combination thereof. The divalent aliphatic group, divalent aromatic group and divalent heterocyclic group may have a substituent, and R ² represents a hydrogen atom or an alkyl group.) A polymer obtained by polymerizing the ethylenically unsaturated monomer represented by the general formula (1), or the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylenically unsaturated monomer The cellulose acylate film according to claim 1, wherein the polymer obtained by copolymerizing with the monomer is a polymer containing a repeating unit represented by the following general formula (2).

(In the formula, R ¹ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and the aliphatic group, aromatic group and heterocyclic group may have a substituent. L is A single bond, a divalent aliphatic group, a divalent aromatic group, a divalent heterocyclic group, —C (═O) —, —O—, —N (R ² ) —, or a combination thereof. And the divalent aliphatic group, divalent aromatic group and divalent heterocyclic group may have a substituent, and R ² represents a hydrogen atom or an alkyl group.) In the general formula (1) or (2), R ¹ is a hydrogen atom or a methyl group, L is a divalent aliphatic group, a divalent aromatic group, —C (═O) —, or —L ^1. -L ² - cellulose acylate film (although according to claim 1 or 2, characterized in that it is, is one of L ¹ and ^{L 2, -C (= O)} -, - O -, - N ( R ² ) — or a combination thereof, and the other represents a divalent aliphatic group, a divalent aromatic group, a divalent heterocyclic group, and the divalent aliphatic group, divalent aromatic group. And the divalent heterocyclic group may have a substituent, R ² represents a hydrogen atom or an alkyl group).   The cellulose acylate film according to any one of claims 1 to 3, wherein the ethylenically unsaturated monomer represented by the general formula (1) is ethyl acetoacetate or ethyl acetoacetate.   A polymer obtained by polymerizing the ethylenically unsaturated monomer represented by the general formula (1), or the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylenically unsaturated monomer The polymer obtained by copolymerizing the monomer is a polymer obtained by copolymerizing the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylenically unsaturated monomer. The cellulose acylate film according to claim 1, wherein the cellulose acylate film is a film.   The other ethylenically unsaturated monomer is at least one selected from the group consisting of (meth) acrylic acid ester, (meth) acrylonitrile, (meth) acryloylmorpholine, and (meth) acrylamide. The cellulose acylate film according to any one of 1 to 5.   A polymer obtained by polymerizing the ethylenically unsaturated monomer represented by the general formula (1), or the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylenically unsaturated monomer The cellulose acylate film according to any one of claims 1 to 6, wherein a polymer obtained by copolymerizing with a monomer has a weight average molecular weight of 500 to 300,000.   A polymer obtained by polymerizing the ethylenically unsaturated monomer represented by the general formula (1), or the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylenically unsaturated monomer The cellulose acylate film according to any one of claims 1 to 6, wherein a polymer obtained by copolymerizing with a monomer has a weight average molecular weight of more than 10,000 and not more than 300,000.   A polymer obtained by polymerizing the ethylenically unsaturated monomer represented by the general formula (1), or the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylenically unsaturated monomer The cellulose acylate film according to any one of claims 1 to 6, wherein a polymer obtained by copolymerizing with a monomer has a weight average molecular weight of 100,000 to 300,000. A polymer obtained by polymerizing the ethylenically unsaturated monomer represented by the general formula (1), or the ethylenically unsaturated monomer represented by the general formula (1) and at least one other ethylenically unsaturated monomer The cellulose acylate film according to any one of claims 1 to 9, wherein the polymer obtained by copolymerizing with a monomer contains 20 to 100 parts by mass with respect to 100 parts by mass of the cellulose acylate. . The said cellulose acylate satisfy | fills following formula (3), The cellulose acylate film as described in any one of Claims 1-10 characterized by the above-mentioned.
Formula (3)
1.5 ≦ A ≦ 3.0
(In the formula, A represents the total acyl substitution degree of cellulose acylate.) The said cellulose acylate satisfy | fills following formula (4), The cellulose acylate film as described in any one of Claims 1-11 characterized by the above-mentioned.
Formula (4)
2.0 ≦ B ≦ 3.0
(In the formula, B represents the degree of acetyl substitution of cellulose acylate.)   Haze is 1% or less, The cellulose acylate film as described in any one of Claims 1-12 characterized by the above-mentioned.   The cellulose acylate film according to any one of claims 1 to 13, wherein a moisture content at 25 ° C and a relative humidity of 80% is 4% or less.   It has a polarizer and two protective films on both sides of the polarizer, and at least one of the protective films is the cellulose acylate film according to any one of claims 1 to 14. A polarizing plate. A liquid crystal display device comprising a liquid crystal cell and two polarizing plates arranged on both sides of the liquid crystal cell, wherein at least one of the polarizing plates is the polarizing plate according to claim 15.

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