JP5280786B2 - Optical compensation film, manufacturing method thereof, polarizing plate and liquid crystal display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical compensation film which is excellent in durability without causing any turbidity even when being exposed to high temperature and high humidity surroundings, and is stably manufactured. <P>SOLUTION: The optical compensation film includes a transparent substrate composed of a polymer film containing a compound represented by formula (I) and containing no phosphate-based compound and an optically anisotropic layer composed of a liquid crystal composition at least containing a liquid crystal compound. In formula (I), R<SP>11</SP>, R<SP>12</SP>, R<SP>13</SP>, R<SP>14</SP>, R<SP>15</SP>, R<SP>16</SP>, and R<SP>17</SP>respectively and independently represent a hydrogen atom or a substituent. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an optical compensation film, a method for producing the same, and a polarizing plate and a liquid crystal display device using the optical compensation film.

  Conventionally, as an optical compensation film for a liquid crystal display device, various optical compensation films having an optical anisotropic layer formed from a liquid crystal composition on a polymer film such as a cellulose acylate film as a support have been proposed. . When producing an optical compensation film having an optically anisotropic layer made of a liquid crystal composition, an alignment film is formed on the surface of a polymer film to be a transparent support, and the alignment control ability of the alignment film is used to obtain an optical film. It is common to form an anisotropic layer. For example, Patent Documents 1 to 3 propose a technique for stably obtaining an optically anisotropic layer having desired optical characteristics.

  Various polymerizers effective for moldability have been proposed for polymer films used as transparent supports. In particular, phosphate plasticizers are widely used. On the other hand, with respect to the polymer film used as the transparent support, it has been proposed to add various additives not only for the plasticizer but also for the purpose of controlling the light absorption wavelength and the optical properties in the UV region ( For example, Patent Documents 4 and 5).

About the optical compensation film of the said structure, when exposed to an environment of high temperature and high humidity, it may become cloudy, and the improvement in the point of durability is calculated | required. Further, it is not easy to stably form an optically anisotropic layer having desired optical characteristics with good reproducibility, and improvements are demanded.
JP-A-8-43624 JP 2007-248620 A JP 2007-57607 A, JP 2006-282799 A, JP 2006-305751 A,

  The present invention provides an optical compensation film that does not cause turbidity even when exposed to high-temperature and high-humidity environments, has good durability, and can be stably manufactured; and uses the optical compensation film Thus, it is an object to provide a polarizing plate and a liquid crystal display device having good performance.

（上記式中、Ｒ¹¹、Ｒ¹²、Ｒ¹³、Ｒ¹⁴、Ｒ¹⁵、Ｒ¹⁶、及びＲ¹⁷はそれぞれ独立に水素原子又は置換基を表す。）
［２］ 前記光学異方性層が、前記液晶組成物を少なくとも配向させる工程を経て形成される層であり、当該工程の最高温度Ｔmaxが、前記液晶組成物の等方性相転移温度Ｔisoより１０〜６０℃低い温度であることを特徴とする［１］の光学補償フィルム。 As a result of various studies by the inventor in order to solve the above problems, the additive added to the polymer film used as the transparent support is a turbidity generated when exposed to a high temperature and high humidity environment. Furthermore, the additive in the support is mixed into the optical anisotropic layer from the support in the step of forming the optical anisotropic layer, and the presence of the additive forms the optical anisotropic layer. The knowledge that stability was impaired was acquired. Based on this finding, further investigations have been made and the present invention has been completed.
Means for solving the above problems are as follows.
[1] A transparent support comprising a polymer film containing a compound represented by the following formula (I) and not containing a phosphate compound, and an optically anisotropic layer comprising at least a liquid crystal composition containing a liquid crystal compound. An optical compensation film.

(In the above formula, R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ each independently represents a hydrogen atom or a substituent.)
[2] The optically anisotropic layer is a layer formed through at least a step of aligning the liquid crystal composition, and a maximum temperature Tmax in the step is higher than an isotropic phase transition temperature Tiso of the liquid crystal composition. The optical compensation film according to [1], wherein the temperature is lower by 10 to 60 ° C.

［式中、Ｙ¹¹、Ｙ¹²及びＹ¹³は、それぞれ独立に置換されていてもよいメチン又は窒素原子を表し；
Ｌ¹、Ｌ²及びＬ³は、それぞれ独立に単結合又は二価の連結基を表し；
Ｈ¹、Ｈ²及びＨ³は、それぞれ独立に一般式（Ｉ−Ａ）：

（一般式（Ｉ−Ａ）中、
ＹＡ¹及びＹＡ²は、それぞれ独立にメチン又は窒素原子を表し；
ＸＡは、酸素原子、硫黄原子、メチレン又はイミノを表し；
＊は上記一般式（Ｉ）におけるＬ¹〜Ｌ³側と結合する位置を表し；
＊＊は上記一般式（Ｉ）におけるＲ¹〜Ｒ³側と結合する位置を表す。）
又は一般式（Ｉ−Ｂ）：

（一般式（Ｉ−Ｂ）中、
ＹＢ¹及びＹＢ²は、それぞれ独立にメチン又は窒素原子を表し；
ＸＢは、酸素原子、硫黄原子、メチレン又はイミノを表し；
＊は上記一般式（Ｉ）におけるＬ¹〜Ｌ³側と結合する位置を表し；
＊＊は上記一般式（Ｉ）におけるＲ¹〜Ｒ³側と結合する位置を表す。）を表し；
Ｒ¹、Ｒ²及びＲ³は、それぞれ独立に下記一般式（Ｉ−Ｒ）：
一般式（Ｉ−Ｒ）
−（−Ｌ²¹−Ｑ²）_n1−Ｌ²²−Ｌ²³−Ｑ¹
（一般式（Ｉ−Ｒ）中、は一般式（Ｉ）におけるＨ¹〜Ｈ³側と結合する位置を表し；
Ｌ²¹は単結合又は二価の連結基を表し；
Ｑ²は少なくとも１種類の環状構造を有する二価の基を表し；
ｎ¹は、０〜４の整数を表し、Ｌ²²は、＊＊−Ｏ−、＊＊−Ｏ−ＣＯ−、＊＊−ＣＯ−Ｏ−、＊＊−Ｏ−ＣＯ−Ｏ−、＊＊−Ｓ−、＊−Ｎ（Ｒ）−、＊＊−ＣＨ₂−、＊＊−ＣＨ＝ＣＨ−又は＊＊−Ｃ≡Ｃ−を表し、ここで、＊＊はＱ²側と結合する位置を表し；
Ｌ²²は、＊＊−Ｏ−、＊＊−Ｏ−ＣＯ−、＊＊−ＣＯ−Ｏ−、＊＊−Ｏ−ＣＯ−Ｏ−、＊＊−Ｓ−、＊−Ｎ（Ｒ¹⁰¹）−、＊＊−ＣＨ₂−、＊＊−ＣＨ＝ＣＨ−又は＊＊−Ｃ≡Ｃ−を表し、Ｒ¹⁰¹は、炭素数１〜５のアルキル基を表し、＊＊はＱ²側と結合する位置を表し；
Ｌ²³は、−Ｏ−、−Ｓ−、−Ｃ（＝Ｏ）−、−ＮＨ−、−ＣＨ₂−、−ＣＨ＝ＣＨ−及びＣ≡Ｃ−ならびにこれらの組み合わせからなる群より選ばれる二価の連結基を表し；
Ｑ¹は重合性基又は水素原子を表す）
を表す。］ [3] The optical compensation film of [1] or [2], wherein the liquid crystal composition contains at least one liquid crystal compound represented by the following formula (II).

[Wherein Y ¹¹ , Y ¹² and Y ¹³ each independently represent a methine group or a nitrogen atom which may be substituted;
L ¹ , L ² and L ³ each independently represents a single bond or a divalent linking group;
H ¹ , H ² and H ³ are each independently represented by the general formula (IA):

(In the general formula (IA),
YA ¹ and YA ² each independently represents a methine or nitrogen atom;
XA represents an oxygen atom, a sulfur atom, methylene or imino;
* Represents the position of bonding to the L ^{1 to} L ³ side in the above general formula (I);
** represents a position bonded to the R ^{1 to} R ³ side in the general formula (I). )
Or general formula (IB):

(In the general formula (IB),
YB ¹ and YB ² each independently represent a methine or nitrogen atom;
XB represents an oxygen atom, a sulfur atom, methylene or imino;
* Represents the position of bonding to the L ^{1 to} L ³ side in the above general formula (I);
** represents a position bonded to the R ^{1 to} R ³ side in the general formula (I). );
R ¹ , R ² and R ³ are each independently the following general formula (IR):
General formula (IR)
-(-L ²¹ -Q ² ) _n1 -L ²² -L ²³ -Q ¹
(In the general formula (IR), represents a position bonded to the H ^{1 to} H ³ side in the general formula (I);
L ²¹ represents a single bond or a divalent linking group;
Q ² represents a divalent group having at least one cyclic structure;
n ¹ represents an integer of 0 to 4, and L ²² represents ** — O—, ** — O—CO—, ** — CO—O—, ** — O—CO—O—, **. -S -, * - N (R ) -, ** - CH 2 -, ** - CH = CH- or ** - C≡C- represent, where ** is a position to bind to Q ² side Represents;
L ²² represents **-O-, **-O-CO-, **-CO-O-, **-O-CO-O-, **-S-, * -N (R ¹⁰¹ )-. , ** — CH ₂ —, ** — CH═CH— or ** — C≡C—, R ¹⁰¹ represents an alkyl group having 1 to 5 carbon atoms, and ** binds to the Q ² side. Represents the position;
L ²³ is selected from the group consisting of —O—, —S—, —C (═O) —, —NH—, —CH ₂ —, —CH═CH— and C≡C—, and combinations thereof. Represents a valent linking group;
Q ¹ represents a polymerizable group or a hydrogen atom)
Represents. ]

[4] The in-plane retardation Re (550) at a wavelength of 550 nm of the polymer film is 50 to 120 nm, and the thickness direction retardation Rth (550) of the same wavelength is 50 to 120 nm. The optical compensation film according to any one of [3].
[5] A polarizing plate having at least the optical compensation film according to any one of [1] to [4] and a polarizer.
[6] A liquid crystal display device having the optical compensation film of any one of [1] to [4] and / or the polarizing plate of [5].
[7] The liquid crystal display device according to [6], wherein the liquid crystal display device is a TN mode or OCB mode liquid crystal display device.
[8] A method for producing an optical compensation film according to any one of [1] to [4],
An alignment step of aligning at least a liquid crystal composition containing a liquid crystal compound, and a step of fixing the liquid crystal composition in an alignment state to form an optically anisotropic layer,
The method for producing an optical compensation film, wherein a maximum temperature Tmax in the alignment step is 10 to 60 ° C. lower than an isotropic phase transition temperature Tiso of the liquid crystal composition.

  According to the present invention, there is provided an optical compensation film which does not become turbid even when exposed to a high temperature and high humidity environment, has good durability and can be stably manufactured; By using it, a polarizing plate and a liquid crystal display device having good performance can be provided.

Hereinafter, the present invention will be described in detail. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
In the present specification, Re (λ) and Rth (λ) represent in-plane retardation (nm) and retardation in the thickness direction (nm) at wavelength λ, respectively. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments).
When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (if there is no slow axis, any in-plane film The light is incident at a wavelength of λ nm from the inclined direction in steps of 10 degrees from the normal direction to 50 degrees on one side with respect to the film normal direction of the rotation axis of KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.
In the above case, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value is calculated by KOBRA 21ADH or WR after changing its sign to negative.
In addition, the retardation value is measured from the two inclined directions, with the slow axis as the tilt axis (rotation axis) (in the absence of the slow axis, the arbitrary direction in the film plane is the rotation axis), Rth can also be calculated from the following formula (X) and formula (XI) based on the value, the assumed value of the average refractive index, and the input film thickness value.

注記：
上記のＲｅ（θ）は法線方向から角度θ傾斜した方向におけるレターデーション値をあらわす。また、式中、ｎｘは面内における遅相軸方向の屈折率を表し、ｎｙは面内においてｎｘに直交する方向の屈折率を表し、ｎｚはｎｘ及びｎｙに直交する方向の屈折率を表す。ｄは膜厚を表す。

Note:
The above Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction. In the formula, nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction orthogonal to nx in the plane, and nz represents the refractive index in the direction orthogonal to nx and ny. . d represents a film thickness.

In the case where the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film having no so-called optical axis, Rth (λ) is calculated by the following method.
Rth (λ) is from −50 degrees to +50 degrees with respect to the normal direction of the film, with Re (λ) being the in-plane slow axis (determined by KOBRA 21ADH or WR) and the tilt axis (rotating axis). In each of the 10 degree steps, light of wavelength λ nm is incident from the inclined direction and measured at 11 points. Based on the measured retardation value, the assumed average refractive index, and the input film thickness value, KOBRA 21ADH or WR is calculated.
In the above measurement, the assumed value of the average refractive index may be a value in a polymer handbook (John Wiley & Sons, Inc.) or a catalog of various optical films. Those whose average refractive index is not known can be measured with an Abbe refractometer. Examples of the average refractive index values of main optical films are given below:
Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).
The KOBRA 21ADH or WR calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.
Further, in this specification, unless a measurement wavelength is particularly added, it is assumed that Re and Rth are at a wavelength of 550 nm.

1. TECHNICAL FIELD The present invention relates to an optical compensation film having a transparent support made of a polymer film containing a compound of the following formula (I) and an optically anisotropic layer made of a liquid crystal composition containing at least a liquid crystal compound.

In the above formula (I), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ each independently represents a hydrogen atom or a substituent.

  Among additives used for the purpose of improving the film formability of a polymer film or for the purpose of adjusting optical properties, a coating liquid for a liquid crystal composition containing a liquid crystal compound on a transparent support In some cases, the coating solution is extracted by the solvent of the coating solution. Due to the presence of the extracted additive (specifically, a phosphate compound added as a plasticizer), the isotropic phase transition temperature of the liquid crystal composition fluctuates, and the formation stability of the optically anisotropic layer is improved. It may be damaged. Since the compound represented by the above formula (I) is difficult to be extracted by the solvent of the coating solution, the formation stability of the optically anisotropic layer is kept good. Further, some additives may cause turbidity when the polymer film is exposed to a high temperature and high humidity environment, but the compound represented by the above formula (I) contains this. Even if the polymer film is exposed to an environment of high temperature and high humidity, it does not cause turbidity. By using this polymer film, durability under high temperature and high humidity can be improved.

Hereinafter, various materials used for production of the optical compensation film will be described.
1. -1 Transparent support In this invention, the polymer film containing the compound represented by the said formula (I) is used as a transparent support.

R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , and R ¹⁷ in the above formula (I) each independently represent a hydrogen atom or a substituent.

  In the above formula (I), it is preferable to combine substituents so that the horizontal direction (left-right direction) of the paper surface is the molecular long axis direction.

  Preferably, the substituent is preferably a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, for example, Methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl group), cycloalkyl group (preferably having 3 to 30 carbon atoms, more preferably 3 carbon atoms) 10 to 10 substituted or unsubstituted cycloalkyl groups such as cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, and bicycloalkyl groups (preferably having 5 to 30 carbon atoms, more preferably 5 to 5 carbon atoms). 10 substituted or unsubstituted bicycloalkyl groups, ie preferably 5-30 carbon atoms, more preferably carbon atoms A monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 10 atoms, for example, bicyclo [1.2.2] heptan-2-yl, bicyclo [2.2.2] octane-3- Yl), an alkenyl group (preferably a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, such as a vinyl group or an allyl group), a cycloalkenyl group (preferably a carbon atom). A substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms, more preferably 3 to 10 carbon atoms, that is, preferably a hydrogen atom of a cycloalkene having 3 to 30 carbon atoms, more preferably 3 to 10 carbon atoms. For example, 2-cyclopenten-1-yl, 2-cyclohexen-1-yl), bicycloalkenyl group (substituted or unsubstituted bicyclyl group). Rhoalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, more preferably 5 to 10 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom of a bicycloalkene having one double bond. For example, bicyclo [2.2.1] hept-2-en-1-yl, bicyclo [2.2.2] oct-2-en-4-yl), an alkynyl group (preferably a carbon atom) A substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, such as an ethynyl group or a propargyl group, an aryl group (preferably 6 to 30 carbon atoms, more preferably a carbon atom number) 6-10 substituted or unsubstituted aryl groups such as phenyl, p-tolyl, naphthyl groups, heterocyclic groups (preferably 5 or 6 membered substituted or unsubstituted, aromatic Is a monovalent group obtained by removing one hydrogen atom from a non-aromatic heterocyclic compound, more preferably 3 to 30 carbon atoms, more preferably 3 to 10 carbon atoms, 5 or 6 membered aromatic. A heterocyclic group. For example, 2-furyl group, 2-thienyl group, 2-pyrimidinyl group, 2-benzothiazolyl group),

A cyano group, a hydroxyl group, a nitro group, a carboxyl group, an alkoxy group (preferably a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms, such as a methoxy group, an ethoxy group, Isopropoxy group, tert-butoxy group, n-octyloxy group, 2-methoxyethoxy group), aryloxy group (preferably having 6 to 30 carbon atoms, more preferably 6 to 10 carbon atoms, substituted or unsubstituted) Aryloxy groups such as phenoxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group), silyloxy group (preferably having 3 to 20 carbon atoms) More preferably a silyloxy group having 3 to 10 carbon atoms, such as a trimethylsilyloxy group, tert- Tildimethylsilyloxy group), a heterocyclic oxy group (preferably a substituted or unsubstituted heterocyclic oxy group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, 1-phenyltetrazole-5-oxy group , 2-tetrahydropyranyloxy group), acyloxy group (preferably formyloxy group, substituted or unsubstituted alkylcarbonyloxy group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, 6 carbon atoms. To 30 and more preferably a substituted or unsubstituted arylcarbonyloxy group having 6 to 10 carbon atoms, such as formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group, p-methoxyphenylcarbonyloxy Group), a carbamoyloxy group (preferably having 1 to 30 carbon atoms) Preferably, the substituted or unsubstituted carbamoyloxy group having 1 to 10 carbon atoms, for example, N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N, N-di-n -Octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group), alkoxycarbonyloxy group (preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, For example, a methoxycarbonyloxy group, an ethoxycarbonyloxy group, a tert-butoxycarbonyloxy group, an n-octylcarbonyloxy group), an aryloxycarbonyloxy group (preferably having 7 to 30 carbon atoms, more preferably having 7 to 7 carbon atoms). 10 substituted or unsubstituted arylo Aryloxycarbonyl group, for example, a phenoxycarbonyl group, p- methoxyphenoxy carbonyloxy group, p-n-hexadecyloxycarbonyl phenoxycarbonyl group),

An amino group (preferably an amino group, 1 to 30 carbon atoms, more preferably a substituted or unsubstituted alkylamino group having 1 to 10 carbon atoms, 6 to 30 carbon atoms, more preferably 6 to 6 carbon atoms); 10 substituted or unsubstituted anilino groups, for example, amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group), acylamino group (preferably formylamino group, carbon atom) A substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms, and a substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms, more preferably 6 to 10 carbon atoms Groups such as formylamino, acetylamino, pivaloylamino, lauroylamino, benzoylamino), amino A rubonylamino group (preferably a substituted or unsubstituted aminocarbonylamino group having 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms, such as a carbamoylamino group, an N, N-dimethylaminocarbonylamino group, N, N-diethylaminocarbonylamino group, morpholinocarbonylamino group), alkoxycarbonylamino group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, for example, Methoxycarbonylamino group, ethoxycarbonylamino group, tert-butoxycarbonylamino group, n-octadecyloxycarbonylamino group, N-methyl-methoxycarbonylamino group), aryloxycarbonylamino group (preferably having 7 to 30 carbon atoms) More preferred Or a substituted or unsubstituted aryloxycarbonylamino group having 7 to 10 carbon atoms, such as phenoxycarbonylamino group, p-chlorophenoxycarbonylamino group, mn-octyloxyphenoxycarbonylamino group), sulfamoyl An amino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms, more preferably 0 to 10 carbon atoms, such as a sulfamoylamino group, N, N-dimethylaminosulfonylamino; Group, Nn-octylaminosulfonylamino group), alkyl and arylsulfonylamino groups (preferably substituted or unsubstituted alkylsulfonylamino having 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms, carbon atoms) Number 6-30, more preferably 6-6-10 carbon atoms substituted or absent Substituted arylsulfonylamino group, for example, methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group), mercapto group, alkylthio group (Preferably, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms, for example, methylthio group, ethylthio group, n-hexadecylthio group), arylthio group (preferably having carbon atoms) 6-30, more preferably a substituted or unsubstituted arylthio group having 6 to 10 carbon atoms, such as phenylthio group, p-chlorophenylthio group, m-methoxyphenylthio group),

Heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, such as 2-benzothiazolylthio group, 1-phenyltetrazole-5 -Ylthio group), a sulfamoyl group (preferably a substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms, more preferably 0 to 10 carbon atoms, such as an N-ethylsulfamoyl group, N- (3- Dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group, N-acetylsulfamoyl group, N-benzoylsulfamoyl group, N- (N′phenylcarbamoyl) sulfamoyl group), sulfo group, alkyl and Arylsulfinyl group (preferably substituted or unsubstituted having 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms) Substituted alkylsulfinyl groups, 6-30, more preferably 6-10 carbon atoms, more preferably 6-10 carbon atoms substituted or unsubstituted arylsulfinyl groups such as methylsulfinyl group, ethylsulfinyl group, phenyl Sulfinyl group, p-methylphenylsulfinyl group), alkyl and arylsulfonyl groups (preferably a substituted or unsubstituted alkylsulfonyl group having 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms, 6 carbon atoms) To 30 and more preferably a substituted or unsubstituted arylsulfonyl group having 6 to 10 carbon atoms, such as methylsulfonyl group, ethylsulfonyl group, phenylsulfonyl group, p-methylphenylsulfonyl group), acyl group (preferably formyl) Groups, 2 to 30 carbon atoms, more preferably carbon atoms A substituted or unsubstituted alkylcarbonyl group having 2 to 10 carbon atoms, a substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms, more preferably 7 to 10 carbon atoms, such as an acetyl group or a pivaloylbenzoyl group) An aryloxycarbonyl group (preferably a substituted or unsubstituted aryloxycarbonyl group having 7 to 30 carbon atoms, more preferably 7 to 10 carbon atoms, such as a phenoxycarbonyl group, an o-chlorophenoxycarbonyl group, m, -Nitrophenoxycarbonyl group, p-tert-butylphenoxycarbonyl group),

An alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxycarbonyl group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, such as a methoxycarbonyl group, an ethoxycarbonyl group, a tert-butoxycarbonyl group, n- Octadecyloxycarbonyl group), a carbamoyl group (preferably a substituted or unsubstituted carbamoyl group having 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms, such as a carbamoyl group, an N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- (methylsulfonyl) carbamoyl group), aryl and heterocyclic azo group (preferably having 6 to 30 carbon atoms, more preferably carbon atoms) 6-10 substituted or unsubstituted arylazo groups, 3-30 carbon atoms, More preferably a substituted or unsubstituted heterocyclic azo group having 3 to 10 carbon atoms, such as phenylazo group, p-chlorophenylazo group, 5-ethylthio-1,3,4-thiadiazol-2-ylazo group), imide Group (preferably N-succinimide group, N-phthalimide group), phosphino group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, such as dimethylphosphine group. A fino group, a diphenylphosphino group, a methylphenoxyphosphino group), a phosphinyl group (preferably a substituted or unsubstituted phosphinyl group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, such as a phosphinyl group, Dioctyloxyphosphinyl group, diethoxyphosphinyl group), phosphinyloxy group (preferably A substituted or unsubstituted phosphinyloxy group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, such as diphenoxyphosphinyloxy group, dioctyloxyphosphinyloxy group), phosphinyl An amino group (preferably a substituted or unsubstituted phosphinylamino group having 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms, such as a dimethoxyphosphinylamino group, a dimethylaminophosphinylamino group; ), A silyl group (preferably a substituted or unsubstituted silyl group having 3 to 30 carbon atoms, more preferably 3 to 10 carbon atoms, such as a trimethylsilyl group, a tert-butyldimethylsilyl group, or a phenyldimethylsilyl group). Represents.

  Among the above substituents, those having a hydrogen atom may be substituted with the above groups after removing this. Examples of such functional groups include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group, and an arylsulfonylaminocarbonyl group. Examples thereof include a methylsulfonylaminocarbonyl group, a p-methylphenylsulfonylaminocarbonyl group, an acetylaminosulfonyl group, and a benzoylaminosulfonyl group.

Among the above substituents, more preferable are a halogen atom, an alkyl group, an aryl group, an alkoxy group, a cyano group, a hydroxyl group, a carboxyl group, and an arylsulfonyl group, and more preferable are an alkyl group, an alkoxy group, A hydroxyl group, a carboxyl group, and a phenylsulfonyl group; For example, R ¹¹ and R ¹⁵ are each an alkyl group; R ¹² , R ¹³ , and R ¹⁶ are hydrogen atoms; R ¹⁴ and R ¹⁷ are each independently an alkyl group, an alkoxy group, a hydroxyl group, a carboxyl group , A phenylsulfonyl group (more preferably, R ¹⁷ is a phenylsulfonyl group, and R ¹⁴ is an alkoxy group).
Moreover, when there are two or more substituents in one molecule, these substituents may be the same or different. Further, if possible, they may be linked to each other to form a ring (including a condensed ring with a ring described in the general formula).

  The compound represented by the general formula (I) used in the present invention is preferably a compound that is substantially free from volatilization in all processes for producing an optical compensation film and a liquid crystal display device. The compound represented by the general formula (I) used in the present invention may be used alone or in combination of two or more. The addition amount varies depending on the optical properties and the like to be imparted to the film, but is preferably 2 to 20% by mass, more preferably 4 to 15% by mass, and further preferably 5 to 10% by mass. The wavelength dispersion adjusting agent is preferably added and mixed in advance with a film-forming melt or solution before film formation.

  Preferred examples of the compound represented by the formula (I) include compounds represented by the following formula (Ia). However, it is not limited to these.

In formula (Ia), R ¹ is —C _m H _{2m + 1} (m is an integer of 0 to 15), R ² is —C _n H _{2n + 1} (n is an integer of 0 to 10), and R ³ represents —C _p H _{2p + 1} (p is an integer of 0 to 10), preferably m is 1 to 10, n is 1 to 7, and p is 1 to 7 It is. More preferably, m is 3 to 10, n is 1 to 5, and p is 1 to 5.

  The compound represented by the above formula (I) acts as a retardation increasing agent, and by adding this, Re (550) of the polymer film is in the range of 50 to 120 nm and Rth (550) is in the range of 50 to 120 nm. Can be adjusted. An optical compensation film having a polymer film exhibiting retardation in this range as a transparent support exhibits a good optical compensation ability. From the same viewpoint, Re (550) of the polymer film is preferably 60 to 110 nm, and more preferably 70 to 100 nm. Rth (550) is preferably 60 to 110 nm, and more preferably 70 to 100 nm.

  The polymer film used as the transparent support is preferably transparent, and specifically, a transparent polymer film having a light transmittance of 80% or more is preferable. Polymer films that can be used as a transparent support include polymer films composed of cellulose esters (eg, cellulose acetate, cellulose diacetate, cellulose triacetate), cyclic polyolefin polymers, cyclic polyolefin copolymers, norbornene polymers, polymethyl methacrylate, and the like. Is mentioned. Commercially available polymers (for norbornene-based polymers, Aaton (registered trademark), ZEONEX (registered trademark), Apel (registered trademark), etc.) may be used. A film made of cellulose ester is preferred, and a film made of lower fatty acid ester of cellulose is more preferred. Lower fatty acid means a fatty acid having 6 or less carbon atoms. Particularly, the number of carbon atoms is preferably 2 (cellulose acetate), 3 (cellulose propionate) or 4 (cellulose butyrate). Of these cellulose esters, a film made of cellulose acetate is particularly preferable. Further, mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate can also be used.

  Even in the case of a conventionally known polymer such as polycarbonate or polysulfone that easily develops birefringence, the birefringence can be expressed by modifying the molecule as described in the pamphlet of International Publication WO00 / 26705. If controlled, it can also be used as a transparent support in the present invention.

As said polymer, a powder or a particulate thing can be used, and the pelletized thing can also be used.
The water content of the polymer is preferably 1.0% by mass or less, more preferably 0.7% by mass or less, and most preferably 0.5% by mass or less. Moreover, it is preferable that the said moisture content is 0.2 mass% or less depending on the case. When the water content of the polymer is not within the preferred range, it is preferable to use the polymer after drying the polymer by drying air or heating.
These polymers may be used alone or in combination of two or more polymers.

Examples of the cellulose ester include a cellulose ester compound and a compound having an ester-substituted cellulose skeleton obtained by biologically or chemically introducing a functional group from cellulose as a raw material, and among them, cellulose acylate is particularly preferable.
In addition, as a polymer as a main component of the polymer film used by this invention, it is preferable to use the above-mentioned cellulose acylate. Here, the “polymer as the main component” indicates a polymer when it is composed of a single polymer, and when it is composed of a plurality of polymers, it is the most mass fraction of the constituent polymers. Indicates a high polymer.

The cellulose ester 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 further preferable, and a lower fatty acid having 2 to 4 carbon atoms is most preferable.
The cellulose acylate is an ester of cellulose and carboxylic acid. In the cellulose acylate, all or part of the hydrogen atoms of the hydroxyl groups present at the 2-position, 3-position and 6-position of the glucose unit constituting the cellulose are substituted with acyl groups. Examples of the acyl group include, for example, acetyl group, propionyl group, butyryl group, isobutyryl group, pivaloyl group, heptanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, and hexadecanoyl group. Examples include a noyl group, an octadecanoyl group, a cyclohexanecarbonyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, and a cinnamoyl group. As the acyl group, acetyl group, propionyl group, butyryl group, dodecanoyl group, octadecanoyl group, pivaloyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group are preferable, acetyl group, propionyl group, butyryl group Is most preferred.
The cellulose ester may be an ester of cellulose and a plurality of acids. Cellulose acylate may be substituted with a plurality of acyl groups.

When the substitution degree of the acetyl group (carbon number 2) substituted on the hydroxyl group of cellulose of cellulose acylate is SA and the substitution degree of the acyl group of 3 or more carbon atoms substituted on the hydroxyl group of cellulose is SB, By adjusting SA and SB, it is possible to adjust the Re dependency of the produced cellulose ester film and the humidity dependence of the retardation. The humidity dependency of retardation is a change in retardation due to humidity.
The cellulose ester used in the present invention preferably has a total substitution degree (total acylation degree) represented by SA + SB of 2.70 <SA + SB ≦ 3.00, more preferably 2.88 ≦ SA + SB ≦ 3.00. More preferably, 2.89 ≦ SA + SB ≦ 2.99, still more preferably 2.90 ≦ SA + SB ≦ 2.98, and particularly preferably 2.92 ≦ SA + SB ≦ 2.97. By increasing SA + SB, Re obtained after the heat treatment can be increased, and the humidity dependency of retardation can also be improved. In addition, when all the hydroxyl groups of the cellulose of a cellulose acylate are substituted by the acyl group, the total substitution degree represented by SA + SB is 3.00.
Moreover, the humidity dependence of the retardation of a cellulose ester film can be adjusted by adjusting SB. By increasing SB, the humidity dependency of retardation can be reduced and the melting point is lowered. In consideration of the humidity dependence of the retardation and the balance of the melting point, the range of SB is preferably 0 <SB ≦ 3.0, more preferably 0 <SB ≦ 1.0, and even more preferably 0.1 ≦ SB ≦ 0.7.

The cellulose ester can be synthesized by a known method.
For example, the basic principle of the cellulose acylate synthesis method is described in Nobuhiko Umeda et al., Wood Chemistry, 180-190 (Kyoritsu Shuppan, 1968). A typical synthesis method of cellulose acylate includes a liquid phase acylation method using a carboxylic acid anhydride-carboxylic acid-sulfuric acid catalyst. Specifically, first, a cellulose raw material such as cotton linter or wood pulp is pretreated with an appropriate amount of carboxylic acid such as acetic acid, and then introduced into a precooled acylated mixture to be esterified to obtain a complete cellulose acylate (2 The total of the degree of acyl substitution at position 3, 3 and 6 is approximately 3.00). The acylated mixed solution generally contains a carboxylic acid as a solvent, a carboxylic anhydride as an esterifying agent, and sulfuric acid as a catalyst. In addition, the carboxylic acid anhydride is usually used in a stoichiometrically excessive amount relative to the total of the cellulose that reacts with the carboxylic acid anhydride and the water present in the system.

  Subsequently, after completion of the acylation reaction, water or hydrous acetic acid is added in order to hydrolyze the excess carboxylic anhydride remaining in the system. Further, in order to partially neutralize the esterification catalyst, an aqueous solution containing a neutralizing agent (for example, calcium, magnesium, iron, aluminum or zinc carbonate, acetate, hydroxide or oxide) is added. Also good. Further, the obtained complete cellulose acylate is saponified and aged by maintaining it at 20 to 90 ° C. in the presence of a small amount of acylation reaction catalyst (generally, remaining sulfuric acid), and the desired degree of acyl substitution and degree of polymerization are obtained. Change to cellulose acylate. When the desired cellulose acylate is obtained, the catalyst remaining in the system is completely neutralized using the neutralizing agent or the like, or water or dilute acetic acid without neutralizing the catalyst. Cellulose acylate solution is put into (or water or dilute acetic acid is put into cellulose acylate solution) to separate cellulose acylate, and the desired cellulose acylate is obtained by washing and stabilizing treatment. Can do.

  The degree of polymerization of the cellulose acylate is preferably from 150 to 500, more preferably from 200 to 400, and even more preferably from 220 to 350 in terms of viscosity average degree of polymerization. The viscosity average degree of polymerization can be measured according to the description of Uda et al.'S intrinsic viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Science, Vol. 18, No. 1, pages 105-120, 1962). The method for measuring the viscosity average degree of polymerization is also described in JP-A-9-95538.

In addition, cellulose acylate having a small amount of low molecular components has a high average molecular weight (degree of polymerization), but its viscosity is lower than that of ordinary cellulose acylate. Such a cellulose acylate having a small amount of low molecular components can be obtained by removing the low molecular components from cellulose acylate synthesized by an ordinary method. The removal of the low molecular components can be performed by washing the cellulose acylate with an appropriate organic solvent. In addition, cellulose acylate having a small amount of low molecular components can be obtained by synthesis. When synthesizing cellulose acylate having a small amount of low molecular components, the amount of sulfuric acid catalyst in the acylation reaction is preferably adjusted to 0.5 to 25 parts by mass with respect to 100 parts by mass of cellulose. When the amount of the sulfuric acid catalyst is within the above range, cellulose acylate that is preferable in terms of molecular weight distribution (uniform molecular weight distribution) can be synthesized. The degree of polymerization and molecular weight distribution of cellulose acylate can be measured by gel permeation chromatography (GPC) or the like.
The raw material cotton of cellulose ester and the synthesis method are also described in pages 7 to 12 of the Japan Society of Invention Disclosure (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society of Invention).

On the other hand, in order to reduce the color shift (color shift) of the liquid crystal display device, it is also important to set the Rth of the transparent support within a predetermined range.
The ratio Re (450 nm) / Rth (450 nm) of Re and Rth at a wavelength of 450 nm in the visible light region is 0.10 to 0.95 times Re (550 nm) / Rth (550 nm) at a wavelength of 550 nm. 4 to 0.8 times is preferable, and 0.5 to 0.7 times is more preferable.
In addition, Re (650 nm) / Rth (650 nm) at a wavelength of 650 nm is 1.01 to 1.9 times Re (550 nm) / Rth (550 nm), preferably 1.1 to 1.7 times. 3 to 1.6 times is more preferable.
Note that Re / Rth in each of R, G, and B is preferably in the range of 0.1 to 0.8.
Further, the retardation (Rth) in the thickness direction of the entire optical compensation film has a function for canceling the retardation of the liquid crystal layer in the thickness direction at the time of black display, and thus is preferable depending on the mode of each liquid crystal layer. The range is also different.

  In the case of using a cellulose acetate film for the transparent support, it is preferable to contain a retardation increasing agent in the film. Regarding preferred compound examples and production methods thereof, JP 2000-154261 A and JP 2000- No. 111914.

On the other hand, as described above, some additives have an adverse effect in terms of durability and formation stability of the optically anisotropic layer. As a result of investigations by the present inventors, phosphate plasticizers such as triphenyl phosphate, which have been widely used as plasticizers in the past, are one cause of turbidity in high temperature and high humidity environments, and are optically anisotropic. This is a factor that is extracted by the solvent of the coating liquid for the conductive layer and impairs the formation stability of the optically anisotropic layer. Accordingly, it is preferable that the polymer film used as the transparent support does not contain a phosphate plasticizer. Examples of phosphate plasticizers include triphenyl phosphate, biphenyl diphenyl phosphate, monomethylphenyl phosphate, tributyl phosphate, tricresyl phosphate, tris (chloroethyl) phosphate, trixylenyl phosphate, tri (butylated phenyl) phosphate, bisphenol A Including flame retardant phosphate compounds such as bis-diphenyl phosphate (t-butylphenyl diphenyl phosphate), resorcinol bis-diphenyl phosphate, tri (isopropylated phenyl) phosphate, and the present invention transparently supports polymer films not containing these It is preferably used as a body.
Therefore, the aspect which uses the compound of this invention and does not use a phosphate type compound for the polymer film of this invention is preferable.

  In addition, it is preferable that the birefringence ((DELTA) n: nx-ny) of a cellulose acetate film is 0.00025-0.00088. The birefringence {(nx + ny) / 2−nz} in the thickness direction of the cellulose acetate film is preferably 0.00088 to 0.005.

  Examples of the polymer solution containing the polymer and various additives include, for example, JP-A Nos. 58-127737, 61-106628, JP-A-2-276830, JP-A-4-259511, and JP-A-5-163301. No. 9-95544 No. 10-45950 No. 10-95854 No. 11-71463 No. 11-302388 No. 11-322946 No. 11-322947 No. 11-322947 The preparation can be carried out according to the preparation methods described in JP-A-11-323017, JP-A-2000-53784, JP-A-2000-273184, and JP-A-2000-273239. Specifically, the polymer and the solvent are mixed and stirred to swell, and optionally cooled or heated to dissolve, and then filtered to obtain a polymer solution.

  The polymer concentration in the polymer solution to be prepared is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and most preferably 15 to 30% by mass. The polymer concentration can be adjusted to a predetermined concentration when the polymer is dissolved in a solvent. Further, after preparing a solution with a low concentration (for example, 4 to 14% by mass) in advance, the solution may be concentrated by evaporating the solvent or the like. Furthermore, after preparing a high concentration solution in advance, it may be diluted. Moreover, the concentration of the polymer can be lowered by adding an additive.

  As a main solvent used when preparing a polymer solution (preferably a cellulose ester solution), an organic solvent which is a good solvent for the polymer can be preferably used. As such an organic solvent, an organic solvent having a boiling point of 80 ° C. or lower is more preferable from the viewpoint of reducing the drying load. The boiling point of the organic solvent is more preferably 10 to 80 ° C, and particularly preferably 20 to 60 ° C. Moreover, the organic solvent whose boiling point is 30-45 degreeC depending on the case can also be used suitably as said main solvent.

  Examples of such a main solvent include halogenated hydrocarbons, esters, ketones, ethers, alcohols and hydrocarbons, and these may have a branched structure or a cyclic structure. The main solvent may have two or more functional groups of esters, ketones, ethers and alcohols (that is, —O—, —CO—, —COO—, —OH). Furthermore, the hydrogen atom in the hydrocarbon portion of the ester, ketone, ether and alcohol may be substituted with a halogen atom (particularly a fluorine atom). In addition, the main solvent of the polymer solution (preferably cellulose ester solution) used for the production of the polymer film used in the production method of the present invention, when composed of a single solvent, indicates that solvent, When it consists of a solvent, it shows the solvent with the highest mass fraction among the constituent solvents. Preferred examples of the main solvent include halogenated hydrocarbons.

As said halogenated hydrocarbon, a chlorinated hydrocarbon is more preferable, for example, a dichloromethane, chloroform, etc. are mentioned, A dichloromethane is further more preferable.
Examples of the ester include methyl formate, ethyl formate, methyl acetate, and ethyl acetate.
Examples of the ketone include acetone and methyl ethyl ketone.
Examples of the ether include diethyl ether, methyl-tert-butyl ether, diisopropyl ether, dimethoxymethane, 1,3-dioxolane, 4-methyldioxolane, tetrahydrofuran, methyltetrahydrofuran, 1,4-dioxane and the like.
As said alcohol, methanol, ethanol, 2-propanol etc. are mentioned, for example.
Examples of the hydrocarbon include n-pentane, cyclohexane, n-hexane, benzene, toluene and the like.

  Examples of the organic solvent used in combination with these main solvents include halogenated hydrocarbons, esters, ketones, ethers, alcohols and hydrocarbons, and these may have a branched structure or a cyclic structure. The organic solvent may have any two or more of ester, ketone, ether and alcohol functional groups (that is, —O—, —CO—, —COO—, —OH). Furthermore, the hydrogen atom in the hydrocarbon portion of the ester, ketone, ether and alcohol may be substituted with a halogen atom (particularly a fluorine atom).

As said halogenated hydrocarbon, a chlorinated hydrocarbon is more preferable, for example, a dichloromethane, chloroform, etc. are mentioned, A dichloromethane is further more preferable.
Examples of the ester include methyl formate, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, and pentyl acetate.
Examples of the ketone include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone.
Examples of the ether include diethyl ether, methyl-tert-butyl ether, diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, 4-methyldioxolane, tetrahydrofuran, methyltetrahydrofuran, anisole, and phenetole. Etc.
Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2-butanol, cyclohexanol, and 2-fluoro. Examples include ethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol. Preferred is an alcohol having 1 to 4 carbon atoms, more preferred is methanol, ethanol or butanol, and most preferred is methanol or butanol.
Examples of the hydrocarbon include n-pentane, cyclohexane, n-hexane, benzene, toluene, xylene and the like.
Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol, 2-butoxyethanol, and methyl acetoacetate.

When the polymer constituting the polymer film used in the present invention contains a hydrogen-bonding functional group such as a hydroxyl group, ester, or ketone, it is 5 to 30% by mass in the total solvent, more preferably 7 to 25% by mass, and still more preferably. It is preferable from a viewpoint of the peeling load reduction from a casting support body to contain 10-20 mass% alcohol. Examples of the polymer containing a hydrogen bonding functional group include cellulose acylate.
By adjusting the alcohol content, it is possible to easily adjust the expression of Re and Rth of the polymer film. Specifically, by increasing the alcohol content, the heat treatment temperature can be set relatively low, and the reach range of Re and Rth can be further increased.
Further, the polymer solution used for the production of the polymer film used in the production method of the present invention has a small proportion of volatilization together with the halogenated hydrocarbon in the initial stage of the drying process, and the boiling point gradually concentrated is 95 ° C. or more, and It is preferable to contain 1 to 15% by mass, more preferably 1.5 to 13% by mass, and further preferably 2 to 10% by mass of an organic solvent which is a poor solvent for cellulose ester.

Although the example of the combination of the organic solvent preferably used as a solvent of the polymer solution used for preparation of the polymer film used for this invention is given below, this invention is not limited to these. In addition, the numerical value of a ratio means a mass part.
(1) Dichloromethane / methanol / ethanol / butanol = 80/10/5/5
(2) Dichloromethane / methanol / ethanol / butanol = 80/5/5/10
(3) Dichloromethane / isobutyl alcohol = 90/10
(4) Dichloromethane / acetone / methanol / propanol = 80/5/5/10
(5) Dichloromethane / methanol / butanol / cyclohexane = 80/8/10/2
(6) Dichloromethane / methyl ethyl ketone / methanol / butanol = 80/10/5/5
(7) Dichloromethane / butanol = 90/10
(8) Dichloromethane / acetone / methyl ethyl ketone / ethanol / butanol = 68/10/10/7/5
(9) Dichloromethane / cyclopentanone / methanol / pentanol = 80/2/15/3
(10) Dichloromethane / methyl acetate / ethanol / butanol = 70/12/15/3
(11) Dichloromethane / methyl ethyl ketone / methanol / butanol = 80/5/5/10
(12) Dichloromethane / methyl ethyl ketone / acetone / methanol / pentanol = 50/20/15/5/10
(13) Dichloromethane / 1,3-dioxolane / methanol / butanol = 70/15/5/10
(14) Dichloromethane / dioxane / acetone / methanol / butanol = 75/5/10/5/5
(15) Dichloromethane / acetone / cyclopentanone / ethanol / isobutyl alcohol / cyclohexane = 60/18/3/10/7/2
(16) Dichloromethane / methyl ethyl ketone / acetone / isobutyl alcohol = 70/10/10/10
(17) Dichloromethane / acetone / ethyl acetate / butanol / hexane = 69/10/10/10/1
(18) Dichloromethane / methyl acetate / methanol / isobutyl alcohol = 65/15/10/10
(19) Dichloromethane / cyclopentanone / ethanol / butanol = 85/7/3/5
(20) Dichloromethane / methanol / butanol = 83/15/2
(21) Dichloromethane = 100
(22) Acetone / ethanol / butanol = 80/15/5
(23) Methyl acetate / acetone / methanol / butanol = 75/10/10/5
(24) 1,3-dioxolane = 100
(25) Dichloromethane / methanol = 85/15
(26) Dichloromethane / methanol = 92/8
(27) Dichloromethane / methanol = 90/10
(28) Dichloromethane / methanol = 87/13
(29) Dichloromethane / ethanol = 90/10

  In addition, the detailed description in the case of using a non-halogen organic solvent as the main solvent is described in the Japan Society for Invention and Technology (Publication No. 2001-1745, published on March 15, 2001, Japan Institute of Invention). It can be used and applied in the invention.

In this invention, in order to improve the solubility to the solvent of a polymer, you may include the process of cooling and / or heating the mixture of a polymer and a solvent.
When a mixture of a polymer and a solvent is cooled using a halogen-based organic solvent as a solvent and cellulose acylate as a polymer, the mixture is preferably cooled to −100 to 10 ° C. Moreover, it is preferable to include the process swollen at -10-39 degreeC in the process before a cooling process, and the process heated to 0-39 degreeC in the process after cooling.

When a mixture of a cellulose acylate and a solvent is heated using a halogen-based organic solvent as a solvent, the method includes a step of dissolving cellulose acylate in the solvent by one or more methods selected from the following (a) or (b) It is preferable.
(A) Swell at −10 to 39 ° C. and warm the resulting mixture to 0 to 39 ° C.
(B) Swell at −10 to 39 ° C., heat the obtained mixture to 40 to 240 ° C. at 0.2 to 30 MPa, and cool the heated mixture to 0 to 39 ° C.
Furthermore, when a non-halogen organic solvent is used as the solvent and the mixture of cellulose acylate and the solvent is cooled, it is preferable to include a step of cooling the mixture to −100 to −10 ° C. Moreover, it is preferable to include the process of swelling at -10-55 degreeC in the process before a cooling process, and the process heated to 0-57 degreeC in the process after cooling.

When using a halogen-based organic solvent as a solvent and heating a mixture of cellulose acylate and solvent, the method includes dissolving cellulose acylate in the solvent by one or more methods selected from the following (c) or (d): It is preferable.
(C) Swell at −10 to 55 ° C. and warm the resulting mixture to 0 to 57 ° C.
(D) Swell at −10 to 55 ° C., heat the obtained mixture to 40 to 240 ° C. at 0.2 to 30 MPa, and cool the heated mixture to 0 to 57 ° C.

  The polymer film used as the transparent support can be produced using a solution casting method or a melt film forming method. From the viewpoint of the film surface, the solution casting method is preferred, but the melt film forming method without using a solvent is excellent in terms of productivity and cost.

  In carrying out the solution casting film forming method, a conventional apparatus can be used in accordance with the conventional method. Specifically, the dope (polymer solution) prepared in a dissolving machine (kettle) can be filtered and then temporarily stored in a storage kettle, and the foam contained in the dope can be defoamed for final preparation. The dope is kept at 30 ° C., and is sent from the dope discharge port to the pressure die through a pressure metering gear pump capable of delivering a constant amount of liquid with high accuracy, for example, by the rotational speed, and the dope runs endlessly from the die (slit) of the pressure die. It casts uniformly on the metal support body of the cast part currently cast (casting process). Next, the dope film (also referred to as web) is peeled off from the metal support at the peeling point where the metal support has almost gone around, and then transported to the drying zone, and drying is completed while being transported by a roll group. Details of the casting process and the drying process of the solution casting film-forming method are also described in pages 120 to 146 of JP-A-2005-104148, and can be applied to the present invention as appropriate.

  In the present invention, a metal band or a metal drum can be used as the metal support used when the polymer film before heat treatment is formed.

In order to control the retardation of the polymer film, it is preferable to control the mechanical history applied to the polymer film before the heat treatment, that is, the external force applied to the polymer web in the film forming process. Specifically, when the produced polymer film exhibits a large Re and a negative Rth, the polymer web is preferably 0.1% or more and less than 15%, more preferably 0.5 to 10%, More preferably, the film is stretched by 1 to 8%. In addition, when producing while conveying the polymer film before heat processing, it is preferable to extend | stretch in the said conveyance direction. The residual solvent amount of the polymer web at the time of stretching is calculated based on the following formula and is 5 to 1000%. The amount of residual solvent is preferably 10 to 200%, more preferably 30 to 150%, and still more preferably 40 to 100%.
Residual solvent amount (% by mass) = {(MN) / N} × 100
[In the formula, M represents the mass of the polymer film just before being inserted into the stretching zone, and N represents the mass when the polymer film just before being inserted into the stretching zone was dried at 110 ° C. for 3 hours.]
Moreover, when showing large Re and positive Rth, a polymer web is preferably extended | stretched 15 to 300%, More preferably, it is 18 to 200%, More preferably, it is 20 to 100%. In addition, when producing while conveying the polymer film before heat processing, it is preferable to extend | stretch in the said conveyance direction. The residual solvent amount of the polymer web at the time of stretching is calculated based on the above formula and is 5 to 1000%. The residual solvent amount is preferably 30 to 500%, more preferably 50 to 300%, and still more preferably 80 to 250%.
The draw ratio (elongation) of the polymer web during the drawing can be achieved by the difference in peripheral speed between the metal support speed and the peeling speed (peeling roll draw). By performing such stretching, the expression of retardation can be adjusted.

  If the residual solvent amount is stretched in a state of 5% or more, the haze is not easily increased. If the residual solvent amount is stretched in a state of 1000% or less, the external force applied to the polymer chain can be easily transmitted, and the above-described solvent is contained. There is a tendency that the effect of adjusting the retardation expression by stretching the polymer web is increased. The residual solvent amount of the polymer web can be appropriately adjusted by changing the concentration of the polymer solution, the temperature and speed of the metal support, the temperature and air volume of the drying air, the solvent gas concentration in the drying atmosphere, and the like. it can.

Further, in the step of stretching the polymer web, the film surface temperature of the web is preferably low from the viewpoint of transmitting external force to the polymer, and the temperature of the web is set to (Ts-100) to (Ts-0.1) ° C. Preferably, (Ts-50) to (Ts-1) ° C is more preferable, and (Ts-20) to (Ts-3) ° C is more preferable. Here, Ts represents the surface temperature of the casting support, and when the temperature of the casting support is set to a partially different temperature, it represents the surface temperature at the center of the support.
The polymer web that has been subjected to the stretching process in this manner is then conveyed to the drying zone, and drying is terminated while both ends are clipped by a tenter or conveyed by a roll group.

  The amount of residual solvent in the film thus dried is preferably 0 to 2% by mass, and more preferably 0 to 1% by mass. This film may be conveyed to the heat treatment zone as it is, or may be heat treated offline after the film is wound. The preferred width of the polymer film before heat treatment is 0.5-5 m, more preferably 0.7-3 m. Moreover, when winding up a film once, preferable winding length is 300-30000m, More preferably, it is 500-10000m, More preferably, it is 1000-7000m.

The film-formed polymer film has a moisture permeability of 100 g / (m ² · day) or more, more preferably 100 to 1500 g / (m ² · day), more preferably 200 to 1000 g. / (M ² · day) is more preferable, and 300 to 800 g / (m ² · day) is particularly preferable. In order to prepare a polymer film having a moisture permeability of 100 g / (m ² · day) or more in terms of 80 μm, it is preferable to appropriately control the hydrophilicity / hydrophobicity of the polymer or to reduce the density of the film. The former method includes, for example, a method of appropriately controlling the hydrophilicity / hydrophobicity of the polymer main chain and further introducing a hydrophobic or hydrophilic side chain. The latter method includes, for example, a side chain in the polymer main chain. And the like, selection of the type of solvent used during film formation, and control of the drying rate during film formation.

(Preliminary stretching)
The polymer film formed before the heat treatment in which the residual solvent amount calculated based on the above formula is less than 5% after drying the solvent is subjected to the heat treatment at a temperature T satisfying Tg ₀ ≦ T <Tm _0. It is preferable to perform stretching (hereinafter, the stretching is also referred to as “preliminary stretching”). By performing the preliminary stretching, it is possible to further adjust the expression of Re and Rth in the heat treatment step. Specifically, within the range described below, the heat treatment temperature can be set relatively low, or the reach range of Re and Rth can be increased by lowering the stretching temperature or increasing the stretching ratio. It becomes possible. Moreover, within the range which does not deviate from the meaning of this invention, another process may be included between the pre-drawing process and the heat treatment process.

The pre-stretching is preferably performed at (Tg ₀ −20) to (Tg ₀ +50) ° C., where Tg ₀ (unit: ° C.) is the glass transition temperature before heat treatment of the polymer film. The pre-stretching temperature is more preferably (Tg ₀ −10) to (Tg ₀ +45) ° C., further preferably Tg ₀ to (Tg ₀ +40) ° C., and most preferably (Tg ₀ +5). ~ (Tg ₀ +35) ° C.

  The direction of the pre-stretching is not particularly limited, and when the polymer film before heat treatment is being transported, even if it is longitudinal stretching that is stretched in the transporting direction, it is transverse stretching that is stretched in a direction perpendicular thereto. Although there may be, it is preferable that it is longitudinal stretch. For the longitudinal stretching and lateral stretching methods and preferred embodiments, reference can be made to the section of heat treatment described later. The prestretch ratio is preferably 1 to 500%, more preferably 3 to 400%, still more preferably 5 to 300%, and particularly preferably 10 to 100%. These preliminary stretchings may be performed in one stage or in multiple stages. Here, “preliminary draw ratio (%)” means that obtained by the following formula.

前記予備延伸における延伸速度は１０〜１００００％／分が好ましく、より好ましくは２０〜１０００％／分であり、さらに好ましくは３０〜８００％／分である。

The stretching speed in the preliminary stretching is preferably 10 to 10,000% / min, more preferably 20 to 1000% / min, and further preferably 30 to 800% / min.

(2-3-4) Heat treatment When producing the polymer film used in the present invention, it is preferable to perform the heat treatment at a heat treatment temperature T (unit: ° C) that satisfies the following formula (1). The heat treatment is preferably performed on the web stretched in the preliminary stretching step. The heat treatment is preferably performed while being conveyed.
Formula (1): Tg ₀ <T <Tm ₀
[Wherein, Tg ₀ represents the glass transition temperature (unit: ° C.) of the polymer film before heat treatment, and Tm ₀ represents the melting point (unit: ° C.) of the polymer film before heat treatment. ]

By performing the heat treatment step, the negative birefringence of the polymer increases and desired Re and Rth can be easily obtained. If the heat treatment temperature T is higher than Tg ₀ , sufficient retardation tends to be developed. Further, the heat treatment temperature T is less than Tm _o, handling is easy tends to be easy to manufacture.

  In said Formula (1), the glass transition temperature of the polymer film before heat processing is represented, and a unit is (degreeC). Here, the “glass transition temperature” is a boundary temperature at which the mobility of the polymer constituting the polymer film changes greatly, and can be measured by a measurement method described later.

  The heat treatment temperature T preferably further satisfies the following formula (2).

Formula (2): Tc ₀ ≦ T <Tm ₀

In the formula (2), Tc ₀ represents the crystallization temperature of the polymer film before the heat treatment, and the unit is ° C. In the present invention, the crystallization temperature means a temperature at which the polymer constituting the polymer film forms a regular periodic structure, and a structure observed by X-ray diffraction rapidly grows when the temperature is exceeded.

When the heat treatment temperature T is higher than Tc ₀ , it is presumed that the structure observed by X-ray diffraction can be grown and the retardation can be adjusted, but the polymer can be obtained by carrying out the stretching step before the heat treatment. It can be arranged to some extent in the stretching direction. For this reason, the structure observed by X-ray diffraction can be efficiently and anisotropically grown in the heat treatment step. Further, by setting the stretching temperature in the stretching step lower than the heat treatment temperature, the polymer polymer can be oriented without growing the structure observed by X-ray diffraction. For this reason, there is an advantage that a structure observed by X-ray diffraction can be grown more efficiently in the subsequent heat treatment step. Therefore, it is more preferable that the stretching direction in the stretching step and the transport direction during the heat treatment match from the viewpoint of reducing the heat treatment temperature and extending the reach range of Re and Rth.

  By heat-treating the polymer film at a temperature T that satisfies the conditions of the above formulas (1) and (2), the retardation of the polymer film can be adjusted. In particular, Re can be increased. By performing the heat treatment at a temperature T satisfying the condition of the formula (2), Re usually increases by 15 nm or more than before the heat treatment, but preferably increases by 25 nm or more, more preferably by 50 nm or more. Further, it is more preferable to increase 100 nm or more, still more preferable to increase 150 nm or more, and particularly preferable to increase 200 nm or more. The increase width of Re can be controlled by the above-described pre-stretching conditions (temperature and magnification), heat-treating conditions (particularly temperature), and the like.

  The heat treatment in the heat treatment step is preferably performed while conveying the polymer film. The means for transporting the polymer film is not particularly limited, and typical examples include a means for transporting by a nip roll or a suction drum, a means for transporting while gripping with a tenter clip (a means for floating and transporting by air pressure), and the like. In terms of production efficiency, it is preferably a means for conveying by nip roll. Specifically, a mode in which a nip roll is installed at least before and after the zone where heat treatment is performed and the polymer film is conveyed by passing between the nip rolls can be exemplified.

  The conveyance speed is usually 1 to 500 m / min, preferably 5 to 300 m / min, more preferably 10 to 200 m / min, and still more preferably 20 to 100 m / min. If the conveyance speed is 1 m / min or more, which is the lower limit value, it tends to be preferable in terms of industrially sufficient productivity, and the upper limit value is 500 m / min or less. If it exists, there exists a tendency which becomes preferable at the point that a crystal growth can fully be advanced with a practical heat treatment zone length. If the conveying speed is increased, the color of the film tends to be suppressed, and if the conveying speed is decreased, the heat treatment zone length tends to be shortened. It is preferable to keep the conveyance speed during heat treatment (the speed of devices such as nip rolls and suction drums that determine the conveyance speed) constant.

  As a heat treatment method in the heat treatment step, for example, a method of passing the polymer film through a zone of temperature T, a method of applying hot air to the polymer film being conveyed, and a method of irradiating the polymer film being conveyed with heat rays And a method of bringing the polymer film into contact with a heated roll.

  Preferably, the polymer film is passed through the zone of temperature T while applying hot air while conveying the polymer film. This method has the advantage that the polymer film can be heated uniformly. The temperature in the zone can be maintained at the temperature T by controlling it to a constant temperature with a heater while monitoring it with a temperature sensor, for example. The transport length of the polymer film in the zone of temperature T varies depending on the properties and transport speed of the polymer film to be manufactured, but usually the ratio of (transport length) / (width of transported polymer film) is 0.1 to 0.1. It is preferable to set it to be 100, more preferably 0.5 to 50, and still more preferably 1 to 20. This ratio may be abbreviated as an aspect ratio in this specification. The passage time (heat treatment time) of the zone of temperature T is usually 0.01 to 60 minutes, preferably 0.03 to 10 minutes, and more preferably 0.05 to 5 minutes. By setting it as the said range, it is excellent in expression of retardation and coloring of a film can be suppressed.

  The polymer film may be stretched simultaneously with the heat treatment. The stretching direction during the heat treatment is not particularly limited, but when the polymer film before the heat treatment has anisotropy, it is preferably stretched in the orientation direction of the polymer in the polymer film before the heat treatment. Here, the film having anisotropy means that the ratio of the sound wave propagation speed in the direction in which the sound wave propagation speed is maximum and the sound wave propagation speed in the direction orthogonal thereto is preferably 1.01 to 10.0. More preferably, it is 1.1-5.0, More preferably, it indicates 1.2-2.5. The direction in which the sound wave propagation speed becomes maximum and the sound wave propagation speed in each direction are determined by adjusting the orientation of the film at 25 ° C. and 60% relative humidity for 24 hours, and then measuring the orientation (SST-2500: manufactured by Nomura Corporation). ) Can be obtained as the direction in which the propagation speed of the longitudinal vibration of the ultrasonic pulse is maximized and the propagation speed in each direction.

  For example, when heat treatment is performed while transporting a polymer film using a device having a heating zone between two nip rolls, the rotation speed of the nip roll on the outlet side of the heating zone is higher than the rotation speed of the nip roll on the inlet side of the heating zone. By speeding up, the polymer film can be preferably stretched in the transport direction (longitudinal direction). It can also be stretched by holding both ends of the polymer film with a tenter clip and passing it through a heating zone while spreading it in a direction (lateral direction) perpendicular to the transport direction. By stretching the polymer film in the conveying direction during the heat treatment, the retardation expression can be further adjusted. The draw ratio in the conveying direction is usually 0.8 to 100 times, preferably 1.0 to 10 times, more preferably 1.2 to 5 times. Moreover, the planar shape of the polymer film after heat processing can be improved by extending | stretching a polymer film in the direction orthogonal to a conveyance direction during heat processing. The draw ratio in the direction perpendicular to the transport direction is usually 0.8 to 10 times, preferably 1.0 to 5 times, more preferably 1.1 to 3 times. The stretching speed in the stretching is preferably 20 to 10000% / min, more preferably 40 to 1000% / min, and still more preferably 50 to 500% / min.

In the heat treatment step of the present invention, the polymer film may be contracted during the heat treatment. The contraction is preferably performed during heat treatment. By shrinking the polymer film during the heat treatment, optical properties and / or mechanical properties can be adjusted. The step of shrinking in the width direction can be performed not only during the heat treatment but also before and after the heat treatment. Moreover, the process of contracting in the width direction may be performed in one step, and the contracting process and the stretching process may be repeated.
When shrinking, the shrinkage rate is preferably 5 to 80%, more preferably 10 to 70%, still more preferably 20 to 60%, and most preferably 25 to 50%. In addition, the direction of shrinkage is not particularly limited, but it is preferably performed in a direction orthogonal to the transport direction of the stretching step. The shrinkage rate can be controlled by adjusting the heat treatment temperature or adjusting the external force applied to the film. Specifically, when the end of the film is held by a tenter clip, it can be controlled by the rail widening rate or the like. In addition, when the end of the film is not fixed and is held only by a device such as a nip roll that fixes the film in the transport direction, the distance between the devices fixed in the transport direction and the tension applied to the film And adjustment of the amount of heat given to the film. The shrinkage rate in the width direction can be obtained from the following equation by measuring the full width immediately before and after the film shrinks.

The heat treatment step may be performed only once or a plurality of times. Performing a plurality of times means that the temperature is once lowered to the glass transition Tg ₀ or less after the previous heat treatment is completed, and then the heat treatment is performed while the temperature is again set to be higher than Tg ₀ and lower than Tm _0. . When performing the heat treatment a plurality of times, it is preferable to satisfy the above range of the draw ratio when all the heat treatments are completed. The heat treatment is preferably 3 times or less, more preferably 2 times or less, and most preferably 1 time.

(Cooling after heat treatment)
The polymer film after the heat treatment is cooled to a temperature lower than Tc. The cooling temperature is not particularly limited, but is preferably 100 to 1,000,000 ° C./min, more preferably 1,000 to 100,000 ° C./min, and further preferably 3,000 to 50,000 ° C. Cool film at / min. The temperature range for cooling the film at such a cooling rate is preferably 50 ° C. or more, more preferably 100 to 300 ° C., further preferably 150 to 280 ° C., and 180 to 250 ° C. It is particularly preferred.
By adjusting the cooling rate in this way, the retardation of the resulting polymer film (particularly cellulose acylate film) can be further adjusted. Specifically, the retardation can be improved by increasing the cooling rate. Moreover, the distribution of the orientation of the polymer chain in the thickness direction in the polymer film can be reduced, and the humidity curl of the film can be suppressed. Such an effect can be obtained more sufficiently by controlling the temperature range at which the cooling is performed at a relatively high cooling rate within the above-described preferable range.

  For the cooling rate, a cooling zone maintained at a temperature lower than the heating zone is provided after the heating zone, and the polymer film is sequentially conveyed to these zones, the cooling roll is brought into contact with the film, or the cooling air is supplied. Can be controlled by spraying the film on the film or immersing the film in a cooled liquid. The cooling rate is not always required to be constant during the cooling step, and the cooling rate may be reduced at the beginning and the end of the cooling step, and the cooling rate may be increased in the meantime. The cooling rate can be determined by measuring the temperature at a plurality of points with a thermocouple arranged on the film membrane surface as described in the examples described later.

(Stretching after heat treatment)
Stretching may be performed following the heat treatment of the polymer film. The stretching performed following the heat treatment may be performed after the polymer film is cooled to a temperature lower than Tc after the heat treatment, or may be performed without being cooled while maintaining the heat treatment temperature. Once the polymer film is cooled, the cooling may be naturally cooled to a temperature lower than Tc, or may be forced to cool to a temperature lower than Tc. Moreover, the state once heated to less than Tc after cooling once may be sufficient. The cooling temperature when the film is once cooled is preferably 50 ° C. or more lower than the heat treatment temperature, more preferably 100 to 300 ° C., and even more preferably 150 to 250 ° C. There is a tendency that the Rth / Re value of the film after the heat treatment can be easily controlled by lowering the cooling temperature by 50 ° C. or more than the heat treatment temperature. Further, it is preferable that the film is once cooled to a cooling temperature and then heated again to a temperature lower than Tc and then stretched. The difference between the heat treatment temperature and the stretching temperature is preferably 1 ° C. or more, more preferably 10 to 200 ° C., further preferably 30 to 150 ° C., and particularly preferably 50 to 100 ° C. By appropriately setting the temperature difference, the Rth / Re value can be controlled. Specifically, if the difference between the heat treatment temperature and the stretching temperature is increased, the Rth / Re value tends to increase, and if the difference is decreased, the change in the Rth / Re value tends to decrease.

  As the stretching method, the method described in the explanation of stretching during the heat treatment can be employed. Stretching may be performed in one stage or in multiple stages. Preferable are a method of stretching in the transport direction by changing the rotational speed of the nip roll and a method of stretching by gripping both ends of the polymer film with tenter clips and spreading them in a direction perpendicular to the transport direction. It is particularly preferable that the film is not stretched during the heat treatment, or is stretched in the transport direction by changing the rotation speed of the nip roll, and after the heat treatment, both ends of the polymer film are gripped with tenter clips, and this is transported. It is the aspect extended | stretched by extending in the direction orthogonal to.

  The draw ratio can be appropriately set according to the retardation required for the polymer film, preferably 1 to 500%, more preferably 3 to 400%, still more preferably 5 to 300%, and particularly preferably 10 to 100%. . The stretching speed is preferably 10 to 10000% / min, more preferably 20 to 1000% / min, and further preferably 30 to 800% / min.

  By stretching after the heat treatment, Re and Rth of the obtained film can be adjusted. For example, by increasing the stretching temperature after heat treatment, Rth can be lowered without changing Re much. Further, by increasing the draw ratio after the heat treatment, Re can be lowered and Rth can be raised. Since these show a substantially linear correlation, it becomes easy to achieve the intended Re and Rth by appropriately selecting the stretching conditions after the heat treatment.

1. -2 Optically anisotropic layer The optical compensation film of the present invention has an optically anisotropic layer formed from a liquid crystal composition containing at least a liquid crystal compound. The optically anisotropic layer is formed by disposing the liquid crystal composition on the surface (for example, the surface of an alignment film formed on a transparent support), controlling the alignment, and fixing the alignment state. The As the liquid crystal compound, a rod-like liquid crystal compound or a discotic liquid crystal compound (discotic liquid crystal compound) is preferable.
Examples of the rod-like liquid crystal compound include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. The rod-like liquid crystal compound is fixed by introducing a polymerizable group into the terminal structure of the rod-like liquid crystal compound (similar to the disk-like liquid crystal described later) and utilizing this polymerization / curing reaction. As a specific example, JP-A-2006-209073 discloses an example in which a polymerizable nematic rod-like liquid crystal compound is cured with ultraviolet rays. Moreover, not only the above-mentioned low molecular liquid crystal compound but also a polymer liquid crystal compound can be used. The high molecular liquid crystal compound is a polymer having a side chain corresponding to the low molecular liquid crystal compound as described above. An optical compensation sheet using a polymer liquid crystal compound is described in JP-A-5-53016.

Regarding discotic liquid crystal compounds, various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by the Chemical Society of Japan, Quarterly Chemical Review, No. 22, Liquid Crystals). Chemistry, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985), J. Zhang et al., J. Am. Chem.Soc., Vol.116, page 2655 (1994)). The polymerization of the discotic liquid crystal compound is described in JP-A-8-27284.
In order to fix the discotic liquid crystal compound by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystal compound. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Therefore, the discotic liquid crystal compound having a polymerizable group is preferably a compound represented by the following formula (A).

(A) D (-LP) _n
Where D is a discotic core; L is a divalent linking group; P is a polymerizable group; and n is an integer from 4 to 12.
An example of the disk-shaped core (D) is shown below. In each of the following examples, LP (or PL) means a combination of a divalent linking group (L) and a polymerizable group (P).

  Examples of the discotic liquid crystal compound used for the production of the optically anisotropic layer include paragraph number [0052] in JP-A-2006-76992 and paragraph number [0040] in JP-A-2007-2220. ] To [0063] are preferable, for example, a compound represented by the following general formula (II) is preferable. These discotic liquid crystal compounds are preferable because they exhibit high birefringence. Among the compounds represented by the following general formula (II), compounds showing a discotic nematic phase are particularly preferable.

（一般式（Ｉ−Ａ）中、
ＹＡ¹及びＹＡ²は、それぞれ独立にメチン又は窒素原子を表し；
ＸＡは、酸素原子、硫黄原子、メチレン又はイミノを表し；
＊は上記一般式（Ｉ）におけるＬ¹〜Ｌ³側と結合する位置を表し；
＊＊は上記一般式（Ｉ）におけるＲ¹〜Ｒ³側と結合する位置を表す。）
又は一般式（Ｉ−Ｂ）：

（一般式（Ｉ−Ｂ）中、
ＹＢ¹及びＹＢ²は、それぞれ独立にメチン又は窒素原子を表し；
ＸＢは、酸素原子、硫黄原子、メチレン又はイミノを表し；
＊は上記一般式（Ｉ）におけるＬ¹〜Ｌ³側と結合する位置を表し；
＊＊は上記一般式（Ｉ）におけるＲ¹〜Ｒ³側と結合する位置を表す。）を表し；
Ｒ¹、Ｒ²及びＲ³は、それぞれ独立に下記一般式（Ｉ−Ｒ）：
一般式（Ｉ−Ｒ）
−（−Ｌ²¹−Ｑ²）_n1−Ｌ²²−Ｌ²³−Ｑ¹
（一般式（Ｉ−Ｒ）中、は一般式（Ｉ）におけるＨ¹〜Ｈ³側と結合する位置を表し；
Ｌ²¹は単結合又は二価の連結基を表し；
Ｑ²は少なくとも１種類の環状構造を有する二価の基を表し；
ｎ¹は、０〜４の整数を表し、Ｌ²²は、＊＊−Ｏ−、＊＊−Ｏ−ＣＯ−、＊＊−ＣＯ−Ｏ−、＊＊−Ｏ−ＣＯ−Ｏ−、＊＊−Ｓ−、＊−Ｎ（Ｒ）−、＊＊−ＣＨ₂−、＊＊−ＣＨ＝ＣＨ−又は＊＊−Ｃ≡Ｃ−を表し、ここで、＊＊はＱ²側と結合する位置を表し；
Ｌ²²は、＊＊−Ｏ−、＊＊−Ｏ−ＣＯ−、＊＊−ＣＯ−Ｏ−、＊＊−Ｏ−ＣＯ−Ｏ−、＊＊−Ｓ−、＊−Ｎ（Ｒ¹⁰¹）−、＊＊−ＣＨ₂−、＊＊−ＣＨ＝ＣＨ−又は＊＊−Ｃ≡Ｃ−を表し、Ｒ¹⁰¹は、炭素数１〜５のアルキル基を表し、＊＊はＱ²側と結合する位置を表し；
Ｌ²³は、−Ｏ−、−Ｓ−、−Ｃ（＝Ｏ）−、−ＮＨ−、−ＣＨ₂−、−ＣＨ＝ＣＨ−及びＣ≡Ｃ−ならびにこれらの組み合わせからなる群より選ばれる二価の連結基を表し；
Ｑ¹は重合性基又は水素原子を表す）
を表す。］ [Wherein Y ¹¹ , Y ¹² and Y ¹³ each independently represent a methine group or a nitrogen atom which may be substituted;
L ¹ , L ² and L ³ each independently represents a single bond or a divalent linking group;
H ¹ , H ² and H ³ are each independently represented by the general formula (IA):

(In the general formula (IA),
YA ¹ and YA ² each independently represents a methine or nitrogen atom;
XA represents an oxygen atom, a sulfur atom, methylene or imino;
* Represents the position of bonding to the L ^{1 to} L ³ side in the above general formula (I);
** represents a position bonded to the R ^{1 to} R ³ side in the general formula (I). )
Or general formula (IB):

(In the general formula (IB),
YB ¹ and YB ² each independently represent a methine or nitrogen atom;
XB represents an oxygen atom, a sulfur atom, methylene or imino;
* Represents the position of bonding to the L ^{1 to} L ³ side in the above general formula (I);
** represents a position bonded to the R ^{1 to} R ³ side in the general formula (I). );
R ¹ , R ² and R ³ are each independently the following general formula (IR):
General formula (IR)
-(-L ²¹ -Q ² ) _n1 -L ²² -L ²³ -Q ¹
(In the general formula (IR), represents a position bonded to the H ^{1 to} H ³ side in the general formula (I);
L ²¹ represents a single bond or a divalent linking group;
Q ² represents a divalent group having at least one cyclic structure;
n ¹ represents an integer of 0 to 4, and L ²² represents ** — O—, ** — O—CO—, ** — CO—O—, ** — O—CO—O—, **. -S -, * - N (R ) -, ** - CH 2 -, ** - CH = CH- or ** - C≡C- represent, where ** is a position to bind to Q ² side Represents;
L ²² represents **-O-, **-O-CO-, **-CO-O-, **-O-CO-O-, **-S-, * -N (R ¹⁰¹ )-. , ** — CH ₂ —, ** — CH═CH— or ** — C≡C—, R ¹⁰¹ represents an alkyl group having 1 to 5 carbon atoms, and ** binds to the Q ² side. Represents the position;
L ²³ is selected from the group consisting of —O—, —S—, —C (═O) —, —NH—, —CH ₂ —, —CH═CH— and C≡C—, and combinations thereof. Represents a valent linking group;
Q ¹ represents a polymerizable group or a hydrogen atom)
Represents. ]

  Further, preferable examples of the discotic liquid crystal compound include compounds described in JP-A-2005-301206.

  A liquid crystal compound as described in JP-A-2007-102205 has a birefringence wavelength dispersion that is closer to the birefringence wavelength dispersion of the liquid crystal compound in the liquid crystal cell, and therefore can be preferably used. Particularly preferred skeletons are shown below.

In the formula (A), the divalent linking group (L) is selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —CO—, —NH—, —O—, —S—, and combinations thereof. A divalent linking group is preferred. The divalent linking group (L) is a divalent group in which at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, —CO—, —NH—, —O—, and —S— are combined. More preferably, it is a linking group. The divalent linking group (L) is most preferably a divalent linking group in which at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO- and -O- are combined. . The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The number of carbon atoms in the arylene group is preferably 6-10.
Examples of the divalent linking group (L) are shown below. The left side is bonded to the discotic core (D), and the right side is bonded to the polymerizable group (P). AL represents an alkylene group or an alkenylene group, and AR represents an arylene group. The alkylene group, alkenylene group and arylene group may have a substituent (eg, an alkyl group).

L1: -AL-CO-O-AL-
L2: -AL-CO-O-AL-O-
L3: -AL-CO-O-AL-O-AL-
L4: -AL-CO-O-AL-O-CO-
L5: -CO-AR-O-AL-
L6: -CO-AR-O-AL-O-
L7: -CO-AR-O-AL-O-CO-
L8: -CO-NH-AL-
L9: -NH-AL-O-
L10: -NH-AL-O-CO-
L11: -O-AL-
L12: -O-AL-O-
L13: -O-AL-O-CO-
L14: -O-AL-O-CO-NH-AL-
L15: -O-AL-S-AL-
L16: -O-CO-AR-O-AL-CO-
L17: -O-CO-AR-O-AL-O-CO-
L18: -O-CO-AR-O-AL-O-AL-O-CO-
L19: -O-CO-AR-O-AL-O-AL-O-AL-O-CO-
L20: -S-AL-
L21: -S-AL-O-
L22: -S-AL-O-CO-
L23: -S-AL-S-AL-
L24: -S-AR-AL-

  The polymerizable group (P) of the formula (A) is determined according to the type of polymerization reaction. Examples of the polymerizable group (P) are shown below.

The polymerizable group (P) is preferably an unsaturated polymerizable group (P1, P2, P3, P7, P8, P15, P16, P17) or an epoxy group (P6, P18). More preferably, it is most preferably an ethylenically unsaturated polymerizable group (P1, P7, P8, P15, P16, P17).
In the formula (I), n is an integer of 4 to 12. A specific number is determined according to the type of the disk-shaped core (D). In addition, although the combination of several L and P may differ, it is preferable that it is the same.

  In the liquid crystal composition, the liquid crystal compound is preferably 50% by mass to 99.9% by mass, and 70% by mass to 99.9% by mass with respect to the total amount of the composition (solid content when a solvent is included). More preferably, 80 mass%-99.5 mass% is still more preferable.

  Along with the above liquid crystal compound, the liquid crystalline composition is used in combination with a plasticizer, a surfactant, a polymerizable monomer, etc., to improve the uniformity of the coating film, the strength of the film, the orientation of the liquid crystal compound, etc. be able to. These materials are preferably compatible with the liquid crystal compound and do not inhibit the alignment.

  The liquid crystal composition is preferably a composition curable by polymerization. For example, the liquid crystal composition preferably contains a photopolymerization initiator or a thermal polymerization initiator and is a composition that can be cured by a polymerization reaction by the provision of light or heat. A preferred example of the polymerization initiator includes a compound represented by the following formula (10). The compound represented by the following formula (10) functions as a polymerization initiator that generates a small bulk.

In the formula, X represents a halogen atom; Y represents —CX ₃ , —NH ₂ , —NHR ′, —NR ′ ₂ or —OR ′; R ′ represents an alkyl group or an aryl group; R represents — CX _{3 represents} an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, or a substituted alkenyl group.

  Examples of the compound represented by the formula (10) that can be used as the radical polymerization initiator include compound Nos. Exemplified in [0082] to [0084] of JP-A-2006-251374. 1-44 are included. In particular, Exemplified Compound Nos. No. 41 is preferably used as an alignment film in the present invention, has a high diffusibility to a polyvinyl alcohol-based polymer, and has an effect of promoting not only an optically anisotropic layer but also a crosslinking reaction of unsaturated groups inside the alignment film. And is particularly preferably used.

  The polymer used with the liquid crystal compound is preferably capable of thickening the coating solution. A cellulose ester can be mentioned as an example of a polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The amount of the polymer added is preferably 0.1 to 10% by mass and more preferably 0.1 to 8% by mass with respect to the liquid crystal molecules so as not to inhibit the alignment of the liquid crystal compound.

  Examples of the surfactant include conventionally known compounds, but fluorine compounds are preferable. Specifically, for example, compounds described in JP-A-2001-330725, paragraphs [0028] to [0056], and paragraphs [0069] to [0126] in Japanese Patent Application No. 2003-295212. And the compounds described. Particularly preferred examples include the fluoroaliphatic group-containing polymers described in paragraphs [0054] to [0109] of JP-A-2005-292351.

The thickness of the optically anisotropic layer is preferably 0.5 to 100 μm, and more preferably 0.5 to 30 μm.
The optical properties of the optically anisotropic layer vary depending on the application and the optical properties of the combined support. An example is an example of an optical compensation film for a TN mode liquid crystal display device, and Re (550) of an optically anisotropic layer combined with a transparent support in which Re (550) and Rth (550) are in the preferred range is It is preferably 10 to 100 nm, more preferably 20 to 60 nm; Rth (550) is preferably 40 to 200 nm, more preferably 60 to 150 nm. Another example is an optical compensation film for an OCB mode liquid crystal display device. Re (550) and Rth (550) are optically anisotropic layers combined with a transparent support in the above preferred range. (550) is preferably from 10 to 100 nm, more preferably from 20 to 60 nm; Rth (550) is preferably from 40 to 200 nm, more preferably from 60 to 150 nm.

1. -3 Alignment film The optical compensation film preferably has an alignment film between the transparent support and the optically anisotropic layer.
In the present invention, the alignment film is preferably a layer made of a crosslinked polymer.
The polymer used for the alignment film may be either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent.
The alignment film is formed by reacting a polymer having a functional group or a polymer having a functional group introduced therein with light, heat, pH change, or the like, or is a highly reactive compound. It can be formed by introducing a bonding group derived from a cross-linking agent between polymers using an agent and cross-linking the polymers.

The alignment film composed of a crosslinked polymer can be usually formed by applying a coating solution containing the polymer or a mixture of a polymer and a crosslinking agent on a transparent support, followed by heating or the like.
In the rubbing process described later, it is preferable to increase the degree of crosslinking in order to suppress the dust generation of the alignment film. A value (1- (Ma / Mb)) obtained by subtracting 1 from the ratio (Ma / Mb) of the amount (Ma) of the crosslinking agent remaining after crosslinking to the amount (Mb) of the crosslinking agent added to the coating solution. When Mb)) is defined as the degree of crosslinking, the degree of crosslinking is preferably from 50 to 100%, more preferably from 65 to 100%, particularly preferably from 75 to 100%.

As the polymer used for the alignment film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used. A polymer having both functions can also be used.
Examples of the polymer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleimide copolymer, polyvinyl alcohol, and modified polyvinyl alcohol, poly (N-methylolacrylamide), styrene / vinyltoluene copolymer. Polymers such as coalescence, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, carboxymethyl cellulose, polyethylene, polypropylene and polycarbonate And compounds such as silane coupling agents.
Examples of preferred polymers are water-soluble polymers such as poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol, and gelatin, polyvinyl alcohol, and modified polyvinyl alcohol are preferred. Mention may be made of bil alcohol and modified polyvinyl alcohol.

Among the above polymers, polyvinyl alcohol or modified polyvinyl alcohol is preferable. The polyvinyl alcohol has, for example, a saponification degree of 70 to 100%, generally a saponification degree of 80 to 100%, and more preferably a saponification degree of 85 to 95%.
The degree of polymerization is preferably in the range of 100 to 3,000. Examples of the modified polyvinyl alcohol include those modified by copolymerization (for example, COONa, Si (OX) ₃ , N (CH ₃ ) ₃ .Cl, C ₉ H ₁₉ COO, SO ₃ , Na, C ₁₂ H ₂₅ Etc.), modified by chain transfer (for example, COONa, SH, C ₁₂ H ₂₅ etc. are introduced as modifying groups), modified by block polymerization (modified groups, for example, COOH, CONH ₂ , COOR, C ₆ H _5, etc. are introduced).
The degree of polymerization is preferably in the range of 100 to 3,000. Among these, unmodified or modified polyvinyl alcohol having a saponification degree of 80 to 100% is preferable, and unmodified or alkylthio-modified polyvinyl alcohol having a saponification degree of 85 to 95% is more preferable.

As the modified polyvinyl alcohol used for the alignment film, a reaction product of a compound represented by the following general formula (2) and polyvinyl alcohol is preferable. In the following general formula (2), R ¹ represents an unsubstituted alkyl group, or an alkyl group substituted with an acrylolyl group, a methacryloyl group, or an epoxy group, and W represents a halogen atom, an alkyl group, or an alkoxy group. , X represents an atomic group necessary for forming an active ester, acid anhydride or acid halide, l represents 0 or 1, and n represents an integer of 0-4.

  Moreover, as the modified polyvinyl alcohol used for the alignment film, a reaction product of a compound represented by the following general formula (3) and polyvinyl alcohol is also preferable. In the following general formula (3), X1 represents an atomic group necessary for forming an active ester, acid anhydride or acid halide, and m represents an integer of 2 to 24.

As the polyvinyl alcohol used for reacting with the compound represented by the general formula (2) and the general formula (3), the unmodified polyvinyl alcohol and the copolymer modified one, that is, by chain transfer. Examples thereof include modified products of polyvinyl alcohol such as modified products and modified products by block polymerization.
Preferred examples of the specific modified polyvinyl alcohol are described in detail in JP-A-8-338913.
When using a hydrophilic polymer such as polyvinyl alcohol for the alignment film, it is preferable to control the moisture content from the viewpoint of the degree of hardening, and the controlled moisture content is 0.4 to 2.5%. Is preferable, and it is more preferable that it is 0.6 to 1.6%. The water content can be measured with a commercially available Karl Fischer moisture content measuring device.
The alignment film preferably has a thickness of 10 μm or less.

2. An example of a method for producing an optical compensation film of the present invention is as follows.
(1) forming an alignment film for aligning a liquid crystal compound on a transparent support;
(2) disposing a liquid crystal composition containing a liquid crystal compound on the surface of the alignment film;
(3) a step of aligning the liquid crystal composition on the alignment film;
(4) fixing the liquid crystal composition in the alignment state to form an optically anisotropic layer;
It is a method including.
Hereinafter, each step will be described in detail.

  In the step (1), an alignment film can be formed by preparing a coating liquid containing polyvinyl alcohol or the like, which is the material for forming the alignment film, and applying the coating liquid to the surface of the support. . When using a coating solution to which a crosslinking agent is added, heating or the like may be performed in order to advance the crosslinking reaction. Moreover, it is preferable to rub the surface after forming the film.

In the step (2), a liquid crystal composition containing a liquid crystal compound prepared as a coating solution is applied to the surface of the alignment film. As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane, tetrachloroethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.
The liquid crystal composition can be applied by a known method (eg, bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method). In addition, application | coating of the coating liquid for alignment film formation of the process of (1) can also be performed by the same method.

  In the step (3), the liquid crystal composition is heated to remove the solvent of the coating solution and dried, and the liquid crystal composition is aligned. Conventionally, the alignment temperature in this step is generally determined based on the isotropic phase transition temperature of the liquid crystal compound itself. However, when an optically anisotropic layer is actually formed, a composition in which various additives are added to a liquid crystal compound is used. Therefore, the isotropic phase transition temperature of the composition depends on the isotropic phase of the liquid crystal compound. Compared to the transition temperature, it generally drops. Furthermore, the temperature range in which the composition is in a nematic liquid crystal phase and the temperature range in which the composition transitions to a higher temperature isotropic phase also vary depending on the type of additive. Therefore, it is difficult to stably form an optically anisotropic layer exhibiting desired optical characteristics only by paying attention only to the isotropic phase transition temperature of the liquid crystal compound. Therefore, in the present invention, the temperature of this step is determined by paying attention to the isotropic phase transition temperature of the liquid crystal composition. Specifically, in the present invention, (3) the maximum temperature Tmax in the alignment step is set to a temperature 10 to 60 ° C. lower than the isotropic phase transition temperature Tiso of the liquid crystal composition. More preferably, the maximum temperature Tmax is 15 to 50 ° C. lower than the isotropic phase transition temperature Tiso of the liquid crystal composition, more preferably 20 to 40 ° C.

  In this specification, “isotropic phase transition temperature of a liquid crystal composition containing a liquid crystal compound” is applied to a surface on a transparent support that actually uses a liquid crystal composition containing a liquid crystal compound. And after drying at a predetermined temperature, it means the transition temperature at which the liquid crystal composition transitions from a nematic liquid crystal phase to an isotropic phase. Therefore, it differs from the nematic liquid crystal phase-isotropic phase transition temperature of the liquid crystal compound alone. The liquid crystal composition contains, in addition to the liquid crystal compound, additives necessary for forming the optically anisotropic layer, and additives in the transparent support that are extracted by the organic solvent of the coating liquid at the time of drying. This is because the temperature is lower than the isotropic phase transition temperature of the liquid crystal compound alone. More specifically, the “isotropic phase transition temperature of a liquid crystal composition containing a liquid crystal compound” in the present specification is determined on a support that actually uses a coating liquid of a liquid crystal composition containing a liquid crystal compound ( In the case of using a support having an alignment film, it is applied to the surface of the alignment film), dried at a predetermined temperature, once returned to room temperature, and again heated in a certain temperature rise, and the alignment of the liquid crystal compound is observed in situ. By doing so, it can be obtained. For in-situ observation, for example, a polarizing microscope can be used.

  In addition, as described above, the additive in the polymer film used as the transparent support may be extracted by the organic solvent used for preparing the coating solution when the coating solution is applied. It is desirable not to be extracted. As a result, the isotropic phase transition temperature of the liquid crystal composition is not affected by the presence of the additive in the polymer film used as the transparent support, and the optical properties of the desired optical characteristics are more stably observed. The isotropic layer can be formed with good reproducibility. On the other hand, when the additive in the transparent support is extracted by the solvent of the coating solution and is present in the liquid crystal composition, it is difficult to control the alignment of the liquid crystal composition, which is not desirable.

In the step (4), the liquid crystal composition in the alignment state is irradiated with light and / or heat, the polymerization reaction of the liquid crystal composition proceeds, the alignment state is fixed, and the optically anisotropic layer is formed. Form. The light irradiation for the polymerization is preferably performed using ultraviolet light, radiation energy is preferably 20~5000mJ / cm ^2, further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, it is preferable to carry out light irradiation under heating conditions, and the heating conditions are not particularly limited, but in order not to lower the degree of alignment of the liquid crystal compound, it is more preferably about 120 ° C. or lower. preferable.

Next, the use of the optical compensation film of the present invention will be described.
3. Polarizing plate The present invention also relates to a polarizing plate having at least a polarizing film and the optical compensation film of the present invention. An example of the polarizing plate of the present invention is a polarizing plate having the optical compensation film of the present invention as a protective film on one surface of the polarizing film. When used as a protective film, it is preferable that the back surface (the surface on which the optically anisotropic layer is not formed) of the polymer film as the support is attached to the surface of the polarizing film.
As the polarizing film, for example, a polarizing film obtained by dyeing a polyvinyl alcohol film with iodine and stretching the film is used.
It is preferable that a protective film is also attached to the other surface of the polarizing film, and as such a protective film, a cellulose acylate film, a cyclic polyolefin polymer film, or the like is used.

4). Liquid crystal display device The optical compensation film and the polarizing plate of the present invention are TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), OCB (Optically Compensatory Bend), STN (Vp). (Vertically Aligned) and HAN (Hybrid Aligned Nematic) can be used for liquid crystal display devices in various display modes. In particular, it is suitable for optical compensation of TN mode and OCB mode liquid crystal display devices.

In the aspect of the optical compensation film for a TN mode liquid crystal display device, Re (550) is preferably 20 to 70 nm, more preferably 30 to 60 nm, and Rth (550) is 50 as the entire optical compensation film. It is preferably ˜300 nm, more preferably 80 to 250 nm.
In the aspect of the optical compensation film for the OCB mode liquid crystal display device, Re (550) is preferably 15 to 60 nm, more preferably 25 to 50 nm, as a whole of the optical compensation film; Rth (550) Is preferably from 100 to 350 nm, more preferably from 150 to 250 nm.

  The present invention will be described more specifically with reference to the following 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 is not limited to the specific examples shown below.

[Example 1]
(Preparation of transparent support 1)
The following composition was put into a mixing tank and stirred while heating to 30 ° C. to dissolve each component to prepare a cellulose acetate solution.

Cellulose acetate with an average substitution degree of 2.94 100.0 parts by mass Methylene chloride (first solvent) 517.6 parts by mass Methanol (second solvent) 77.3 parts by mass Silica particles with an average particle size of 16 nm 13 parts by mass (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.)
-The following compound A 11.7 mass parts-The following compound B 7.5 mass parts-Citric acid ester 0.01 mass parts

(1-1) Production of Raw Film A cellulose acylate solution A having the following composition containing compounds A and B was cast using a band casting machine. The film was peeled from the band with a residual solvent amount of about 60%, conveyed by a tenter, and dried at 110 ° C. for 5 minutes and further at 140 ° C. for 10 minutes to obtain an original film having a cellulose acylate film thickness of 80 μm.

(1-2) Stretching process A longitudinal uniaxial stretching process was performed using a roll stretching machine. Drawing conditions are shown below. The roll of the roll drawing machine was an induction heating jacket roll having a mirror-finished surface, and the temperature of each roll could be adjusted individually. The draw ratio was controlled by adjusting the ratio between the peripheral speed of the downstream nip roll and the peripheral speed of the upstream nip roll. The aspect ratio (distance between nip rolls / base inlet width) was adjusted to 0.5, and the stretching speed was 10% / min with respect to the distance between stretching. The draw ratio was set to 22% and the temperature was set to 150 ° C.

  The draw ratio (%) of the film was determined from the following formula by placing marked lines at regular intervals in a direction orthogonal to the film transport direction, measuring the intervals before and after heat treatment. In the examples and comparative examples described later, the stretching ratio of the film was determined by the same method.

(1-3) Heat treatment step Both ends in the film width direction are gripped with a tenter clip, and the width direction is controlled while controlling the distance between the tenter clip that grips one end and the tenter clip that grips the other end. The cellulose acylate film was heat-treated so that no dimensional change occurred.
The heating zone was set to 200 ° C., and the film was allowed to pass for 10 minutes to obtain a transparent support 1.

One side of the roll film is passed over a dielectric heating roll having a temperature of 60 ° C., and the film surface temperature is raised to 40 ° C. Then, an alkaline solution having the following composition is applied at 14 mL / m ² using a bar coater. Then, it was allowed to stay for 10 seconds under a steam far infrared heater (manufactured by Noritake Co., Ltd.) heated to 110 ° C., and then 3 mL / m ^{2 of} pure water was applied using the same bar coater. The film temperature at this time was 40 degreeC. Next, washing with a fountain coater and draining with an air knife were repeated three times, and then the film was retained in a drying zone at 70 ° C. for 2 seconds and dried.
Alkaline solution composition Potassium hydroxide 4.7 parts by weight Water 15.7 parts by weight Isopropanol 64.8 parts by weight Propylene glycol 14.9 parts by weight C ₁₆ H ₃₃ O (CH ₂ CH ₂ O) ₁₀ H (surfactant) 1 .0 parts by mass

(Formation of alignment film)
Thereafter, a coating solution having the following composition was further applied at 28 mL / m ² with a # 16 wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds and further with warm air of 90 ° C. for 150 seconds. Next, the formed film was rubbed so as to be oriented in a direction parallel to the casting direction of the transparent support B-1 (that is, the rubbing axis was parallel to the casting direction of the transparent support 1). )
Alignment film coating solution composition Modified polyvinyl alcohol 20 parts by weight Water 470 parts by weight Methanol 160 parts by weight Glutaraldehyde (crosslinking agent) 1.0 part by weight Irgacure 2959 (manufactured by Ciba Geigy) 0.5 part by weight Citric acid 0.04 part by weight Quen Acid monoethyl ester 0.15 mass parts Citric acid diethyl ester 0.14 mass parts Citric acid triethyl ester 0.03 mass parts

(Preparation of liquid crystal composition 1 for forming an optically anisotropic layer)
A liquid crystal composition 1 for forming an optically anisotropic layer having the following composition was prepared.
-Liquid crystal composition 1 for forming an optically anisotropic layer
Methyl ethyl ketone 270 parts by mass D-112 (Japanese Patent Laid-Open No. 2006-76992) 90 parts by weight Discotic liquid crystal compound-1 (Japanese Patent Laid-Open No. 2001-166144) 10 parts by weight Air interface alignment controller having the following structure 1 part by weight photopolymerization Initiator (Irgacure 907, manufactured by Ciba Geigy) 3 parts by mass Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass

(Determination of isotropic phase transition temperature of liquid crystal composition 1)
The transparent support 1 coated with the alignment film 1 is placed and sent out in the delivery of the manufacturing process for coating the optically anisotropic layer, and a rubbing roll is rotated in the reverse direction along the conveying direction by a rubbing device arranged at the tip. The surface of the alignment film was rubbed by rotation. The prepared liquid crystal composition 1 for forming an optically anisotropic layer was applied to the rubbing treated surface with a # 2 wire bar. Then, it was oriented by drying at 135 ° C. for 1.5 minutes. A part where the liquid crystal composition 1 for optically anisotropic layer is applied is cut out, left for a while at room temperature, and then heated at a rate of 80 ° C. to 10 ° C./min using a heating device (manufactured by METTLER TOLEDO). While heating the sample, the orientation state of the optically anisotropic layer was observed under a polarizing microscope (Nikon Corp.) crossed Nicol. Start the observation at the sample angle with the lowest transmittance, read the temperature at which the luminance rises and the transition from the nematic liquid crystal phase to the isotropic phase begins to appear, and the isotropic phase of the liquid crystal composition containing the liquid crystal compound The transition temperature was used. This liquid crystal composition 1 had an isotropic phase transition temperature of 160 ° C.

(Formation of optically anisotropic layer 101)
The transparent support 1 coated with the alignment film 1 is placed and sent out in the delivery step of the manufacturing process for coating the optically anisotropic layer, and the rubbing roll is rotated in the reverse direction along the transport direction by the rubbing device arranged at the tip. Was rotated to rub the surface of the alignment film. The prepared liquid crystal composition 1 for forming an optically anisotropic layer is applied to the rubbing surface with a # 2 wire bar, and the difference between the isotropic phase transition temperature of the optically anisotropic layer and the maximum drying temperature Was oriented at a temperature of 20 ° C., that is, a drying temperature of 140 ° C. for 1.5 minutes. After that, while maintaining the film temperature at 80 ° C., UV light with an irradiation amount of 200 mJ / cm ² is irradiated with a 120 W / cm metal halide lamp, the polymerization reaction is advanced, the alignment state is fixed, and the optical property is changed. The isotropic layer 101 was formed, and the film was wound into a roll film state at the winding portion to produce the optical compensation film 1.
Only the optically anisotropic layer of the obtained film was transferred to a glass plate, and the optical properties at a measurement wavelength of 550 nm were measured with KOBRA 21ADH. As a result, Re was 45 and Rth was 90 nm.

(Orientation evaluation of liquid crystal compounds)
The orientation of the liquid crystal compound in the optically anisotropic layer applied to the optical compensation film 1 produced in Example 1 was evaluated. Two commercially available polarizing plates are arranged in a crossed Nicol arrangement on a light table provided with a fluorescent lamp, the produced optical compensation film is sandwiched between two polarizing plates, and the polarizing plate absorption axis and the optical compensation film 1 are applied The optical compensation film 1 was arranged in the same direction, and the orientation was evaluated according to the following criteria.
○: The light from the fluorescent lamp is not transmitted, and the liquid crystal compound is nematically aligned.
(Triangle | delta): The light of a fluorescent lamp does not permeate | transmit, but the liquid crystal compound has nematic orientation, but there are some dark parts in some places, and nematic orientation is not enough.
X: Light from a fluorescent lamp is transmitted, and the liquid crystal compound is in an isotropic phase state.
The liquid crystal compound of the optically anisotropic layer 101 of the optical compensation film 1 produced in Example 1 was nematically oriented and evaluated as “◯”.

[Example 2]
In the formation of the optically anisotropic layer 101 of the optical compensation film 1 of Example 1, the difference between the isotropic phase transition temperature of the liquid crystal composition 1 and the maximum temperature of the drying temperature is 35 ° C., that is, the maximum temperature of the drying temperature is set. The optically anisotropic layer 102 was formed in the same manner as in Example 1 except that the temperature was 125 ° C., and the optical compensation film 2 was produced. When the orientation of the liquid crystal compound was evaluated in the same manner as in Example 1, the liquid crystal compound in the optically anisotropic layer of the optical compensation film 2 was nematically aligned and was evaluated as “◯”.

[Example 3]
In the formation of the optically anisotropic layer 101 of the optical compensation film of Example 1, the difference between the isotropic phase transition temperature of the liquid crystal composition 1 and the maximum temperature of the drying temperature is 50 ° C., that is, the maximum temperature of the drying temperature is 110. An optically anisotropic layer 103 was formed in the same manner as in Example 1 except that the temperature was changed to 0 ° C., and an optical compensation film 3 was produced. When the orientation of the liquid crystal compound was evaluated in the same manner as in Example 1, the liquid crystal compound in the optically anisotropic layer of the optical compensation film 3 was nematically aligned and was evaluated as “◯”.

[Example 4]
In the production of the transparent support 1 of the optical compensation film of Example 1, a transparent support 2 was produced in the same manner as in Example 1 except that the following compound C was used instead of the compound B. Re (550) of the transparent support 2 was 80 nm, and Rth (550) was 90 nm. Further, the optically anisotropic layer was formed by the same method as that of the optically anisotropic layer 2 of Example 2, and the optical compensation film 4 was produced. When the orientation of the liquid crystal compound was evaluated in the same manner as in Example 1, the liquid crystal compound in the optically anisotropic layer of the optical compensation film 4 was nematically aligned and was evaluated as “◯”.

[Example 5]
In the production of the transparent support 1 of the optical compensation film of Example 1, the transparent support 3 was produced in the same manner as in Example 1 except that the following compound D was used as the compound B. Re (550) of the transparent support 3 was 85 nm, and Rth (550) was 90 nm. Moreover, the optically anisotropic layer was formed by the same method as that of the optically anisotropic layer 2 of Example 2, and the optical compensation film 5 was produced. When the orientation of the liquid crystal compound was evaluated in the same manner as in Example 1, the liquid crystal compound in the optically anisotropic layer of the optical compensation film 5 was nematically aligned, and the evaluation was “◯”.

[Example 6]
In the production of the transparent support 1 of the optical compensation film of Example 1, the transparent support 4 was produced in the same manner as in Example 1 except that the compound B was replaced with the following compound E. Re (550) of the transparent support 4 was 85 nm, and Rth (550) was 88 nm. Moreover, the optically anisotropic layer was formed by the same method as that of the optically anisotropic layer 2 of Example 2, and the optical compensation film 6 was produced. When the orientation of the liquid crystal compound was evaluated in the same manner as in Example 1, the liquid crystal compound in the optically anisotropic layer of the optical compensation film 6 was nematically aligned, and the evaluation was “◯”.

[Examples 7 to 12]
In forming the optically anisotropic layer 101 of the optical compensation film of Example 1, a liquid crystal for forming an optically anisotropic layer was formed using the liquid crystal compound shown in Table 1 below instead of the liquid crystal composition 1 for forming an optically anisotropic layer. Compositions 2 to 7 were prepared, and optical anisotropic layers 104 to 109 were prepared using the compositions 2 to 7, respectively. At the time of forming each optically anisotropic layer, the difference between the maximum temperature during drying and the isotropic phase transition temperature of each of the liquid crystal compositions 2 to 7 was set to be in the range shown in the following table. . In this manner, optically anisotropic layers 104 to 109 were formed, and optical compensation films 7 to 12 were produced. When the orientation of the liquid crystal compound was evaluated in the same manner as in Example 1, the liquid crystal compound in the optically anisotropic layer of the optical compensation films 7 to 12 was nematically aligned, and the evaluation was “◯”.

[Comparative Example 1]
(Method for producing optical compensation film 21)
(Preparation of transparent support 5)
The following composition was put into a mixing tank and stirred while heating to 30 ° C. to dissolve each component to prepare a cellulose acetate solution.
(Cellulose acetate solution composition)
Cellulose acetate solution composition Inner layer Outer layer Cellulose acetate with 60.9% acetylation 100 parts by weight 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Parts 3.9 parts by weight Methylene chloride (first solvent) 293 parts by weight 314 parts by weight Methanol (second solvent) 71 parts by weight 76 parts by weight 1-butanol (third solvent) 1.5 parts by weight 1.6 parts by weight Silica Fine particles (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.)
0 parts by mass 0.8 parts by mass The following retardation increasing agent 1.5 parts by mass 0 parts by mass

  The obtained inner layer dope and outer layer dope were cast on a drum cooled to 0 ° C. using a three-layer co-casting die. The film having a residual solvent amount of 70% by mass was peeled off from the drum, both ends were fixed with a pin tenter, and the film was dried at 80 ° C. while transporting at a draw ratio of 110% in the transport direction, resulting in a residual solvent amount of 10%. By the way, it was dried at 110 ° C. Then, it dried for 30 minutes at the temperature of 140 degreeC, and produced the cellulose acylate film (Outer layer: 3 micrometer, Inner layer: 75 micrometer, Outer layer: 3 micrometer) whose residual solvent is 0.3 mass%. The resulting cellulose acylate film had a width of 1490 mm and a thickness of 80 μm.

In the same manner as in Example 1, an alignment film was applied on the transparent support 5, and the liquid crystal composition 1 was used in the same manner as in Example 1 on the transparent support 5 on which the alignment film was further applied. Then, the optical anisotropic layer 101 was applied. When the orientation of the liquid crystal compound was evaluated in the same manner as in Example 1, the liquid crystal compound in the optically anisotropic layer of the optical compensation film 22 was nematically aligned, and the evaluation was “◯”.
However, the isotropic phase transition temperature of the liquid crystal composition 1 was 160 ° C. on the support 5. In Example 1, the isotropic phase transition temperature of the liquid crystal composition 1 was 160 ° C., whereas in Comparative Example 1, the temperature decreased to 150 ° C. in the additive (plasticizer) in the transparent support 5. It is considered that triphenyl phosphate and biphenyl diphenyl phosphate) are extracted by the solvent of the coating solution and mixed into the liquid crystal composition, thereby further reducing the isotropic phase transition temperature. As described above, when the transparent support 5 is used, the isotropic phase transition temperature fluctuates due to the influence of the additive in the support, and the stable formation of the optically anisotropic layer having desired optical characteristics may be impaired. is expected.

[Evaluation]
(Durability evaluation)
The optical compensation films 1 to 12 produced in Examples 1 to 12 and the optical compensation film 21 produced in Comparative Example 1 were left in an environment of 80 ° C. and 90% for 500 hours, and then left at room temperature for 24 hours. The turbidity of the optical compensation film was observed and evaluated according to the following criteria.
○ No change.
× Turbidity occurs in the optical compensation film.

(Mounting evaluation in TN mode liquid crystal display device)
-Production of elliptically polarizing plate Iodine was adsorbed on a stretched polyvinyl alcohol film to produce a polarizing film. Next, the support body side of each optical compensation film produced in Examples 1 to 12 and Comparative Example 1 was attached to one side of the polarizing film using a polyvinyl alcohol-based adhesive. The slow axis of the optically anisotropic layer of the optical compensation film and the transmission axis of the polarizing film were arranged in parallel.
Further, a commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Film Co., Ltd.) was saponified in the same manner as described above, and the other side of the polarizing film (the side on which the optical film was not attached) using a polyvinyl alcohol-based adhesive. ). In this manner, an elliptically polarizing plate was produced.

-Production of TN mode liquid crystal display device A pair of polarizing plates (upper polarizing plate and lower polarizing plate) provided in a 20-inch liquid crystal display device (manufactured by Sharp) using a TN type liquid crystal cell is peeled off, instead. The prepared polarizing plates were attached to the viewer side and the backlight side one by one through an adhesive so that the optical film was on the liquid crystal cell side. At this time, each polarizing plate was disposed so that the transmission axis of the polarizing plate on the observer side (upper polarizing plate) and the transmission axis of the polarizing plate on the backlight side (lower polarizing plate) were orthogonal to each other.

-Evaluation of liquid crystal display device The contrast viewing angle was evaluated about each produced liquid crystal display device.
Specifically, the liquid crystal display device left for one week in a room at room temperature and humidity (25 ° C., 60% RH) is displayed from black display (L1) to white display using a measuring instrument (EZ-Contrast 160D, manufactured by ELDIM). The tint and contrast ratio (transmittance during white display / transmittance during black display) were measured in eight stages up to (L8). The contrast is a value calculated from the contrast ratio (transmittance during white display / transmittance during black display). A polar angle range with a contrast ratio of 10 or more and no gradation inversion during black display was measured and evaluated according to the following criteria. The results are shown in the table below.
(Evaluation criteria)
[Evaluation Criteria for Contrast Viewing Angle (Polar Angle Range with Contrast Ratio of 10 or More and No Black-side Gradation Inversion)]
◎ Polar angle 80 ° or more in top / bottom / left / right ○ Polar angle 80 ° or more in three directions, top / bottom / left / right △ Polar angle 80 ° or more in two directions, top / bottom / left / right × Polar angle 80 ° in three directions that's all

[Comparative Example 2]
In Comparative Example 1, an optical compensation film 22 was produced in the same manner as in Comparative Example 1, except that the maximum temperature during drying was 160 ° C. About the obtained optical compensation film 22, evaluation similar to the said Example and comparative example was performed.

  About the optical compensation films 1-12 of Examples 1-12 and the comparative example 1, and 21, 22, the evaluation result of orientation, a durability test, and a contrast viewing angle is shown to the following table | surface.

From the result shown in the said table | surface, while containing the compound represented by the said formula (I), the optical produced in Examples 1-12 which used the cellulose sylate type | system | group film which does not contain a phosphate plasticizer as a transparent support body. Compensation films 1 to 12 were all good in evaluation results for orientation, durability, and contrast viewing angle characteristics.
On the other hand, in the optical compensation film of the comparative example, turbidity occurred in the durability test, and the durability was inferior. This is considered to be caused by using a polymer film to which a phenyl phosphate plasticizer is added as a transparent support. That is, it can be understood that the use of the transparent support not only makes it difficult to stably form an optically anisotropic layer having desired optical characteristics, but also adversely affects durability.

Claims (8)

An optical system comprising a polymer film containing a compound represented by the following formula (I a ), a transparent support containing no phosphate compound, and an optically anisotropic layer comprising a liquid crystal composition containing at least a liquid crystal compound. Compensation film.

(In formula (Ia), R ¹ _{is, -C m H 2m + 1 (} m is an integer) of 0 to 15, R ² _{is, -C n H 2n + 1,} (n is 0 to an integer of And R ³ represents —C _p H _{2p + 1} (p is an integer of 0 to 10).) The optically anisotropic layer is a layer formed through at least the step of aligning the liquid crystal composition, and the maximum temperature Tmax in the step is 10 to 60 from the isotropic phase transition temperature Tiso of the liquid crystal composition. The optical compensation film according to claim 1, wherein the optical compensation film has a low temperature. The optical compensation film according to claim 1, wherein the liquid crystal composition contains at least one liquid crystal compound represented by the following formula (II).

[Wherein Y ¹¹ , Y ¹² and Y ¹³ each independently represent a methine group or a nitrogen atom which may be substituted;
L ¹ , L ² and L ³ each independently represents a single bond or a divalent linking group;
H ¹ , H ² and H ³ are each independently represented by the general formula (IA):

(In the general formula (IA),
YA ¹ and YA ² each independently represents a methine or nitrogen atom;
XA represents an oxygen atom, a sulfur atom, methylene or imino;
* Represents the position of bonding to the L ^{1 to} L ³ side in the above general formula (I);
** represents a position bonded to the R ^{1 to} R ³ side in the general formula (I). )
Or general formula (IB):

(In the general formula (IB),
YB ¹ and YB ² each independently represent a methine or nitrogen atom;
XB represents an oxygen atom, a sulfur atom, methylene or imino;
* Represents the position of bonding to the L ^{1 to} L ³ side in the above general formula (I);
** represents a position bonded to the R ^{1 to} R ³ side in the general formula (I). );
R ¹ , R ² and R ³ are each independently the following general formula (IR):
General formula (IR)
-(-L ²¹ -Q ² ) _n1 -L ²² -L ²³ -Q ¹
(In the general formula (IR), represents a position bonded to the H ^{1 to} H ³ side in the general formula (I);
L ²¹ represents a single bond or a divalent linking group;
Q ² represents a divalent group having at least one cyclic structure;
n ¹ represents an integer of 0 to 4, and L ²² represents ** — O—, ** — O—CO—, ** — CO—O—, ** — O—CO—O—, **. -S -, * - N (R ) -, ** - CH 2 -, ** - CH = CH- or ** - C≡C- represent, where ** is a position to bind to Q ² side Represents;
L ²² represents **-O-, **-O-CO-, **-CO-O-, **-O-CO-O-, **-S-, * -N (R ¹⁰¹ )-. , ** — CH ₂ —, ** — CH═CH— or ** — C≡C—, R ¹⁰¹ represents an alkyl group having 1 to 5 carbon atoms, and ** binds to the Q ² side. Represents the position;
L ²³ is selected from the group consisting of —O—, —S—, —C (═O) —, —NH—, —CH ₂ —, —CH═CH— and C≡C—, and combinations thereof. Represents a valent linking group;
Q ¹ represents a polymerizable group or a hydrogen atom)
Represents. ] The in-plane retardation Re (550) of the polymer film at a wavelength of 550 nm is 50 to 120 nm, and the thickness direction retardation Rth (550) of the same wavelength is 50 to 120 nm. 2. An optical compensation film according to item 1. At least a polarizing plate optical compensating film described, and the polarizer to any one of claims 1-4. The liquid crystal display device having a polarizing plate according to the optical compensation film, and / or claim 5 according to any one of claims 1-4. The liquid crystal display device according to claim 6 , wherein the liquid crystal display device is a TN mode or OCB mode liquid crystal display device. It is a manufacturing method of the optical compensation film given in any 1 paragraph of Claims 1-4 ,
An alignment step of aligning at least a liquid crystal composition containing a liquid crystal compound, and a step of fixing the liquid crystal composition in an alignment state to form an optically anisotropic layer,
The method for producing an optical compensation film, wherein a maximum temperature Tmax in the alignment step is 10 to 60 ° C. lower than an isotropic phase transition temperature Tiso of the liquid crystal composition.