JP2011002823A - Twisted alignment mode liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a twisted alignment mode liquid crystal display in which vertical and horizontal viewing angle characteristics are improved with good balance.SOLUTION: The twisted alignment mode liquid crystal display has: first and second polarizing films; a twisted alignment mode liquid crystal cell having first and second cell substrates disposed between the first and second polarizing films and having a liquid crystal layer disposed between the first and second cell substrates; and first and second optically anisotropic laminated bodies having two optically anisotropic layers 1 and two optically anisotropic layers 2 respectively between the first polarizing film and the liquid crystal cell and between the second polarizing film and the liquid crystal cell, wherein the first optically anisotropic layer 1 has Re of 50-300 nm and Rth of 50-250 nm, the second optically anisotropic layer 2 includes a rod-shaped liquid crystal fixed in a tilted alignment state and has Re of 0-100 nm, and tilt directions of the second optically anisotropic layers 2 of the first and second optically anisotropic laminated bodies and tilt directions of the liquid crystal in the vicinity of the first and second cell substrates are respectively antiparallel to each other.

Description

  The present invention relates to a twisted alignment mode liquid crystal display device with improved contrast in the vertical and horizontal directions of the screen.

Conventionally, various optical compensation films that contribute to improving the viewing angle characteristics of twisted alignment mode liquid crystal display devices such as TN mode liquid crystal display devices have been proposed.
As an example, various optical compensation films having an optical anisotropic layer formed by hybridizing or tilting rod-like liquid crystal molecules and fixing the state have been proposed (for example, Patent Documents 1 and 2).
In recent years, application of a liquid crystal display device not only as a display for a personal computer (PC) but also as a display for a large TV has been attempted and put into practical use. By using the optical compensation film having the above configuration, the viewing angle characteristics of the TN mode liquid crystal display device have been improved. However, for use as a large TV display, the viewing angle characteristics of the top, bottom, left, and right are further improved in a balanced manner. It is hoped that

JP 2002-196139 A JP 2006-195293 A

  An object of the present invention is to provide a twisted alignment mode liquid crystal display device in which the viewing angle characteristics in the vertical and horizontal directions are improved in a well-balanced manner.

The optical compensation film described in the above-mentioned patent documents is a film having an optical anisotropic layer formed by hybridizing or tilting rod-like liquid crystal molecules and fixing the state, and the film is optical Most of them are arranged such that the rubbing direction of the anisotropic layer is orthogonal to the rubbing direction of the liquid crystal cell substrate arranged in the vicinity thereof.
However, the inventors have studied that there is a limit to improving the contrast viewing angle characteristics of the liquid crystal display device by adjusting the optical characteristics and the layer configuration of the optical compensation film while maintaining this orthogonal arrangement. I know that there is.
As a result of further investigation, it was found that the above-mentioned problems can be solved by arranging an optically anisotropic layer having a predetermined characteristic in a predetermined relationship with the cell substrate. It came to be completed.

Means for solving the above problems are as follows.
[1] First and second polarizing films disposed with their absorption axes orthogonal to each other,
First and second cell substrates disposed between the first and second polarizing films (however, the first cell substrate is disposed closer to the first polarizing film, and the second A cell substrate is disposed closer to the second polarizing film), and
A twisted alignment mode liquid crystal cell having at least a liquid crystal layer disposed therebetween, and between the first polarizing film and the liquid crystal cell, and between the second polarizing film and the liquid crystal cell, respectively. A liquid crystal display device having first and second optically anisotropic laminates having at least two optically anisotropic layers 1 and 2.
The order of the arrangement of the first optically anisotropic layer 1 and the optically anisotropic layer 2 in each of the first and second optically anisotropic laminates is symmetrical about the liquid crystal cell,
The optically anisotropic layer 1 has an in-plane retardation at a wavelength of 550 nm of 50 to 300 nm, and a thickness direction retardation of 50 to 250 nm.
The optically anisotropic layer 2 contains a rod-like liquid crystal fixed in an inclined alignment state, and the in-plane retardation at a wavelength of 550 nm is 0 to 100 nm,
The tilt orientation of the optical anisotropic layer 2 in the first optical anisotropic laminate and the tilt orientation of the liquid crystal in the vicinity of the first cell substrate are antiparallel to each other, and the second optical A twisted alignment mode liquid crystal display device in which the tilt orientation of the optically anisotropic layer 2 in the anisotropic laminate and the tilt orientation of the liquid crystal in the vicinity of the second cell substrate of the liquid crystal layer are antiparallel to each other.
[2] The twisted alignment mode liquid crystal display device according to [1], wherein the optically anisotropic layer 2 satisfies the following formula (I):
Formula (I) 20 nm ≦ Re [+40] −Re [−40] ≦ 125 nm
In the equation, Re [θ] is an in-plane retardation value measured from a direction inclined by an angle θ (°) from the normal direction.
[3] The twisted alignment mode liquid crystal display device according to [1] or [2], wherein the optically anisotropic layer 2 and the optically anisotropic layer 1 are arranged in this order from the liquid crystal cell side.
[4] A casting step in which the optically anisotropic layer 1 casts a polymer solution containing at least one cellulose acylate to form a web, and the web formed in the casting step is used as a residual solvent. Including a stretching step of stretching 5 to 100% in the conveying direction while the amount is 100 to 300% by mass, and a drying step of drying the web at a film surface temperature of 50 to 150 ° C. The twisted alignment mode liquid crystal display device according to any one of [1] to [3], which is a film produced by a production process having a volatile content of 10 to 150 mass% and a final residual volatile content of 10 to 50 mass%.
[5] The twisted alignment mode liquid crystal display device according to any one of [1] to [4], wherein the optically anisotropic layer 1 is a film containing at least one cellulose acylate containing a propionyl group or a butyryl group.
[6] The twisted alignment mode liquid crystal display device according to any one of [1] to [3], wherein the optically anisotropic layer 1 is a polymer film containing at least one selected from cycloolefin homopolymers and copolymers.

  According to the present invention, it is possible to provide a twisted alignment mode liquid crystal display device in which the vertical and horizontal viewing angle characteristics are improved in a well-balanced manner.

It is a disassembled perspective view of an example of the TN mode liquid crystal display device of this invention. It is the conceptual diagram used in order to demonstrate the relationship of "anti-parallel".

  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 this specification, Re represents an in-plane retardation value (unit: nm) at a wavelength of 550 nm of a film-like measurement object such as an optically anisotropic layer, film, or laminate, and Rth represents a wavelength. It represents the retardation value in the thickness direction at 550 nm (unit: nm).

Re is measured with KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments) by making light having a wavelength of 550 nm incident in the normal direction of the film-like measurement object.
As a method of changing the measurement wavelength, there are a method of manually exchanging the wavelength selection filter, and a method of measuring the measured value by converting it with a program or the like.
When the film-like measurement object to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth is calculated by the following method.
Rth is a value obtained by using Re as an axis of rotation (determined by KOBRA 21ADH or WR) as a rotation axis. With respect to the normal direction of the film-like object to be measured (with the direction as the rotation axis), light of wavelength λ nm is incident from each inclined direction in 10 ° steps from the normal direction to 50 ° on one side. 6 points are measured, and 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, in the case of a film-like measurement object having a direction in which the retardation value is zero at a certain tilt angle with the in-plane fast axis as the rotation axis from the normal direction, the tilt is larger than the tilt angle. The retardation value in angle is calculated by KOBRA 21ADH or WR after changing its sign to negative.
Note that the retardation value is measured from two inclined directions with the fast axis as the rotational axis (in the absence of the fast axis, the arbitrary direction in the plane of the film-like object to be measured is the rotational axis). Then, based on the value, the assumed value of the average refractive index, and the input film thickness value, Rth can also be calculated from the following equations (A) and (B).

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

In the case where the film-like measurement object to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a measurement object without a so-called optical axis, Rth is calculated by the following method. Is done.
Rth tilted the Re in 10 ° steps from −50 ° to + 50 ° with respect to the film normal direction with the in-plane fast axis (determined by KOBRA 21ADH or WR) as the rotation axis. 11 points are measured by making light having a wavelength of 550 nm incident from the direction, and KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed average refractive index, and the input film thickness value.
In the above measurement, as the assumed value of the average refractive index, values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. 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 as follows: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59). 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.
In the present specification, when the measurement wavelength is not particularly described for Re, Rth, and refractive index, the measurement wavelength is 550 nm.

  Further, in this specification, the “slow axis” of a film-like measurement object such as an optically anisotropic layer, a film, or a laminate is a direction in which the refractive index is maximum, and the “fast axis” , And represents the direction in which the refractive index is minimized. For example, KOBRA 21ADH (manufactured by Oji Scientific Instruments) can be used to measure the slow axis of the measurement object.

  Further, in this specification, an angle such as “45 °”, “orthogonal” or “parallel” means that the angle is within a range of strictly less than ± 5 °. The error from the exact angle is preferably less than 4 °, more preferably less than 3 °.

Hereinafter, several embodiments of the twisted alignment mode liquid crystal display device of the present invention will be described with reference to the drawings. In the following description, the upper side of the drawing will be described as the display surface side, and the lower side of the drawing will be described as the backlight side.
FIG. 1 is an exploded perspective view of a first embodiment of the liquid crystal display device of the present invention. The liquid crystal display device shown in FIG. 1 includes a first polarizer 4 and a second polarizer 5 and a TN mode liquid crystal cell 10 therebetween. Between the liquid crystal cell 10 and the first polarizer 4, and between the liquid crystal cell 10 and the second polarizer 5, the optically anisotropic layer 2 (6, 6 ') and the optically anisotropic layer 1 (7, First and second optically anisotropic laminates 12 and 12 ′ including 7 ′) are disposed. In the first and second optically anisotropic laminates 12 and 12 ′, each optically anisotropic layer has an optically anisotropic layer 2 (6, 6 ′) and an optically anisotropic layer around the liquid crystal cell 10. The conductive layers 1 (7, 7 ′) are arranged in this order, that is, they are symmetrically arranged with the liquid crystal cell 10 as the center. The first and second polarizers 4 and 5 are arranged with their absorption axes 4a (or 4b) and 5a (or 5b) orthogonal to each other.

  The liquid crystal cell 10 includes a first substrate 2 and a second substrate 3 and a liquid crystal layer 1 disposed therebetween. The alignment films (not shown) formed on the inner surfaces of the first substrate 2 and the second substrate 3 are rubbed along directions 2b and 3b perpendicular to each other, and when no drive voltage is applied, The liquid crystal molecules 1a in the liquid crystal layer 1 are twisted and aligned at about 90 °. Therefore, when no driving voltage is applied, the linearly polarized light that has passed through the second polarizer 5 is allowed to pass through the first polarizer 4 because the polarization axis is rotated by passing through the liquid crystal layer 1, and the liquid crystal display device Becomes white. On the other hand, when the driving voltage is applied, the twisted alignment of the liquid crystal molecules 1a at the center in the liquid crystal layer 1 is eliminated, so that the linearly polarized light that has passed through the second polarizer 5 has passed through the liquid crystal layer 1, Blocked by the absorption axis 4a (or 4b) of the first polarizer 4, the liquid crystal display device enters a black display state. However, the liquid crystal molecules 2a and 3a in the vicinity of the first and second substrates 2 and 3 in the liquid crystal layer 1 have predetermined tilt angles 2c and 3c with respect to the substrate surface in both black display and white display. Therefore, the liquid crystal layer 1 is birefringent in the oblique direction, causing a decrease in contrast in the oblique direction. The first and second optically anisotropic laminates 12 and 12 'are formed by the tilt alignment of the liquid crystal molecules 2a and 3a in the vicinity of the first and second substrates 2 and 3 in the liquid crystal layer 1. It acts to optically compensate for refraction.

In the LCD 1 of the present embodiment, two optically anisotropic layers of the optically anisotropic layer 2 (6, 6 ′) and the optically anisotropic layer 1 (7, 7 ′) are used for the optical compensation. There is a feature that. The optically anisotropic layer 2 (6, 6 ') is an optically anisotropic layer containing rod-like liquid crystals 6a, 6'a fixed in a tilted alignment state.
The optically anisotropic layer 2 (6, 6 ') has an in-plane retardation at a wavelength of 550 nm of 0 to 100 nm, preferably 20 to 90 nm, and Re [+40] -Re [-40] of 20 to 125 nm, preferably Is 60-120 nm. Here, Re [θ] is an in-plane retardation value measured from the direction normal to the direction inclined by an angle θ with the fast axis as the rotation axis, and Re [+40] ≧ Re [−40].
The optically anisotropic layer 1 (7, 7 ') has an in-plane retardation at a wavelength of 550 nm of 50 to 300 nm, preferably 100 to 250 nm, and a thickness direction retardation of 50 to 250 nm, preferably 100 to 200 nm. As long as this condition is satisfied, the material is not particularly limited. The optically anisotropic layer 1 (7, 7 ') has an in-plane slow axis (7a, 7'a) due to the orientation of liquid crystal molecules or polymers contained therein, and the direction is the first polarization. It is parallel or orthogonal to the absorption axis 4 a of the film 4 and parallel or orthogonal to the absorption axis 5 a of the second polarizing film 5.

In the LCD 1 of the present embodiment, the tilt direction of the rod-like liquid crystal molecules of the optically anisotropic layer 2 (6, 6 ′) and the liquid crystal cell substrate (2, 3) disposed in the liquid crystal cell substrate (2, 3) disposed closer to each other. The liquid crystal molecules (2a, 3a) are characterized in that the tilt directions are antiparallel.
Here, the inclination azimuth and anti-parallel will be described with reference to FIG.
The optically anisotropic layer 1 (7) and the substrate (2) are defined as a virtual plane P1, and the optically anisotropic layer 1 (8) and the substrate (3) are defined as a virtual plane P2.
The liquid crystal molecules (6a, 6′a) in the optically anisotropic layer 2 and the liquid crystal molecules (2a, 3a) in the vicinity of the substrate are respectively inclined at angles (6c, 6′c and 2c) with respect to the virtual planes P1, P2. , 3c). Here, the major axis direction of the tilted molecule is defined as the tilt axis (6d, 6′d and 2d, 3d) as shown in FIG. The orientation obtained by projecting the tilt axes (6d, 6′d and 2d, 3d) onto the virtual planes P1 and P2 is defined as tilt orientations (6e, 6′e and 2e, 3e) as shown in FIG. When the liquid crystal of the optically anisotropic layer 2 is aligned by rubbing, the rubbing direction and the tilt direction are the same. Similarly, when the liquid crystal molecules in the liquid crystal cell are aligned by rubbing, the rubbing direction and the tilt direction are the same.
The tilt direction (6e, 6'e) of the optically anisotropic layer 2 and the tilt direction (2e, 3e) of the liquid crystal in the vicinity of the cell substrate are parallel but opposite to each other. These relationships are defined as antiparallel.
There are various treatments for orienting rod-like liquid crystal molecules in the optically anisotropic layer 2 (6, 6 '), such as a method of aligning by applying light or a magnetic field in addition to rubbing, a method of imparting alignment regulating force from the alignment film side, etc. However, the tilt direction can be determined based on FIG. 2 by a method other than rubbing.
Here, the tilt direction (6e, 6′e) of the optically anisotropic layer 2 (6, 6 ′) is in the direction inclined by the angle θ from the normal direction in the aforementioned KOBRA 21ADH (manufactured by Oji Scientific Instruments). It can be detected by measuring the retardation value.
Further, the tilt direction of the liquid crystal in the vicinity of the cell substrate can be measured by OPTIPRO (manufactured by Shintech Co., Ltd.).

Hereinafter, various materials that can be used for producing the optical compensation film of the present invention will be described.
1. Optically anisotropic layer 2
In the present invention, a rod-like liquid crystal compound is used for producing the optically anisotropic layer 2.
[Bar-shaped liquid crystal compound]
The rod-like liquid crystalline compound that can be used for forming the optically anisotropic layer 2 is not particularly limited. Examples of rod-like liquid crystalline compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenyl Various rod-like liquid crystals of pyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are included. Moreover, not only a low molecular liquid crystalline compound but a high molecular liquid crystalline compound can also be used. It is more preferable to fix the alignment of the rod-like liquid crystal compound by polymerization. As the liquid crystalline compound, those having a partial structure capable of causing polymerization or crosslinking reaction by actinic rays, electron beams, heat, or the like are suitably used. The number of the partial structures is preferably 1 to 6, more preferably 1 to 3. As the polymerizable rod-like liquid crystalline compound, Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. Nos. 4,683,327, 5,622,648, and 5,770,107, International Publication WO95 / 22586. No. 95/24455, No. 97/00600, No. 98/23580, No. 98/52905, JP-A-1-272551, No. 6-16616, and No. 7-110469. 11-80081, JP 2001-328773, JP 2004-240188, JP 2005-99236, JP 2005-99237, JP 2005-121827, JP It is possible to use the compounds described in 2002-30042 That.

  The rod-like liquid crystal compound used in the present invention may be orientation controlled so that the tilt angle gradually changes (hybrid orientation). In order to control the tilt angle, it is important to control the surface energy of the interface. Specifically, the tilt angle increases by decreasing the surface energy, and the tilt angle tends to decrease by increasing the surface energy. is there. In order to precisely control the tilted alignment state between the horizontal alignment and the vertical alignment, it is preferable to control the surface energy with a tilt angle control agent.

For controlling the tilt angle of the optically anisotropic layer 2 on the air interface side, a predetermined air interface aligning agent described later can be used. Further, the tilt angle of the optically anisotropic layer 2 on the alignment film interface side can be controlled by an alignment film material (predetermined additive described later).
(Air interface side alignment agent)
For the formation of the optically anisotropic layer 2, an aligning agent that promotes the liquid crystal molecules in the vicinity of the air interface side to be in a vertically aligned state may be used. Examples of the alignment agent include a fluoro aliphatic group, a carboxyl group (—COOH), a sulfo group (—SO ₃ H), a phosphonoxy group {—OP (═O) (OH) ₂ }, and salts thereof. A fluoroaliphatic group-containing polymer (hereinafter referred to as “fluorine polymer”) containing at least one hydrophilic group selected from the group, or a fluorine-containing compound represented by the general formula (III) is included.

First, the fluorine polymer will be described.
The fluoropolymer usable in the present invention includes a fluoroaliphatic group, a carboxyl group (—COOH), a sulfo group (—SO ₃ H), a phosphonoxy group {—OP (═O) (OH) ₂ }, and their It contains one or more hydrophilic groups selected from the group consisting of salts. The types of polymers are described in “Revised Chemistry of Polymer Synthesis” (Takayuki Otsu, published by Kagaku Dojin Co., 1968), pages 1-4, for example, polyolefins, polyesters, polyamides, polyimides. , Polyurethanes, polycarbonates, polysulfones, polycarbonates, polyethers, polyacetals, polyketones, polyphenylene oxides, polyphenylene sulfides, polyarylates, polytetrafluoroethylene (PTFE), polyvinylidene fluorides And cellulose derivatives. The fluoropolymer is preferably a polyolefin.

  The fluorine-based polymer is a polymer having a fluoroaliphatic group in the side chain. The fluoroaliphatic group preferably has 1 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms. The aliphatic group may be linear or cyclic, and when it is linear, it may be linear or branched. Of these, a linear fluoroaliphatic group having 6 to 10 carbon atoms is preferable. The degree of substitution with fluorine atoms is not particularly limited, but 50% or more of hydrogen atoms in the aliphatic group are preferably substituted with fluorine atoms, and more preferably 60% or more are substituted. The fluoroaliphatic group is contained in a side chain bonded to the polymer main chain via an ester bond, an amide bond, an imide bond, a urethane bond, a urea bond, an ether bond, a thioether bond, an aromatic ring, or the like. One of the fluoroaliphatic groups is derived from a fluoroaliphatic compound produced by a telomerization method (also referred to as a telomer method) or an oligomerization method (also referred to as an oligomer method). Regarding the production method of these fluoroaliphatic compounds, for example, “Synthesis and Function of Fluorine Compounds” (Supervision: Nobuo Ishikawa, Issue: CMC Co., 1987), “Chemistry of Organic Fluorines Compounds”. II "(Monograph 187, Ed by Milos Hudricky and Attila E. Pavlath, American Chemical Society 1995). The telomerization method is a method of synthesizing a telomer by radical polymerization of a fluorine-containing vinyl compound such as tetrafluoroethylene using an alkyl halide having a large chain transfer constant such as iodide as a telogen (example in Scheme-1). showed that).

  The obtained terminal iodinated telomer is usually subjected to appropriate terminal chemical modification such as [Scheme 2], and led to a fluoroaliphatic compound. These compounds are further converted into a desired monomer structure as needed, and used for the production of a fluoropolymer.

  Specific examples of monomers that can be used in the production of the fluorine-based polymer that can be used in the present invention are listed below, but the present invention is not limited to the following specific examples.

  One embodiment of a fluorine-based polymer that can be used in the present invention is represented by a repeating unit derived from a fluoroaliphatic group-containing monomer (hereinafter sometimes referred to as “fluorine-based monomer”) and the following formula (II): It is a copolymer having a repeating unit containing a hydrophilic group.

In the above formula (II), R ¹ , R ² and R ³³ each independently represents a hydrogen atom or a substituent. Q represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof. L represents an arbitrary group selected from the following linking group group, or a divalent linking group formed by combining two or more thereof.
(Linked group group)
Single bond, —O—, —CO—, —NR ^b — (R ^b represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group), —S—, —SO ₂ —, —P (═O) (OR ^f ) — (R ^f represents an alkyl group, an aryl group, or an aralkyl group), an alkylene group, and an arylene group.

In formula (II), R ¹ , R ² and R ³³ each independently represent a hydrogen atom or a substituent selected from the substituent group exemplified below.
(Substituent group)
An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, still more preferably 1 to 8 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group and the like), alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, More preferably, it is a C2-C8 alkenyl group, for example, a vinyl group, an aryl group, 2-butenyl group, 3-pentenyl group etc., an alkynyl group (preferably C2-C20, more preferably). Is an alkynyl group having 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, such as a propargyl group and a 3-pentynyl group. An aryl group (preferably an aryl group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, still more preferably 6 to 12 carbon atoms, such as a phenyl group, a p-methylphenyl group, A naphthyl group), an aralkyl group (preferably an aralkyl group having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, still more preferably 7 to 12 carbon atoms, such as a benzyl group, a phenethyl group, A 3-phenylpropyl group), a substituted or unsubstituted amino group (preferably an amino group having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, still more preferably 0 to 6 carbon atoms, For example, an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, an anilino group, etc.)

An alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, still more preferably 1 to 10 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, and a butoxy group); An alkoxycarbonyl group (preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably 2 to 10 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group), acyloxy A group (preferably an acyloxy group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably 2 to 10 carbon atoms such as an acetoxy group and a benzoyloxy group), an acylamino group (preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, still more preferably 2 carbon atoms 10 acylamino groups such as acetylamino group and benzoylamino group), alkoxycarbonylamino groups (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably 2 to 2 carbon atoms). 12 alkoxycarbonylamino groups, for example, a methoxycarbonylamino group and the like, and aryloxycarbonylamino groups (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, still more preferably 7 carbon atoms). To 12 aryloxycarbonylamino groups, such as phenyloxycarbonylamino group, and sulfonylamino groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably carbon atoms). 1 to 12 sulfonylamino groups, for example, Sulfonylamino groups, benzenesulfonylamino groups, etc.), sulfamoyl groups (preferably 0-20 carbon atoms, more preferably 0-16 carbon atoms, still more preferably 0-12 carbon atoms sulfamoyl groups, , Sulfamoyl group, methylsulfamoyl group, dimethylsulfamoyl group, phenylsulfamoyl group and the like), carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, still more preferably A carbamoyl group having 1 to 12 carbon atoms, and examples thereof include an unsubstituted carbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group, and a phenylcarbamoyl group).

An alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, still more preferably 1 to 12 carbon atoms, such as a methylthio group and an ethylthio group), an arylthio group ( Preferably it is a C6-C20, More preferably, it is a C6-C16, More preferably, it is a C6-C12 arylthio group, For example, a phenylthio group etc. are mentioned, A sulfonyl group (preferably C1-C1). 20, more preferably a sulfonyl group having 1 to 16 carbon atoms, still more preferably 1 to 12 carbon atoms, and examples thereof include a mesyl group and a tosyl group), a sulfinyl group (preferably having a carbon number of 1 to 20, and more. A sulfinyl group having 1 to 16 carbon atoms, more preferably 1 to 12 carbon atoms, is preferable. A ureido group (preferably a benzenesulfinyl group), a ureido group (preferably a ureido group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably 1 to 12 carbon atoms. Ureido group, methylureido group, phenylureido group, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, and further preferably having 1 to 12 carbon atoms) Group such as diethyl phosphoramide group and phenylphosphoric acid amide group), hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group Group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably A heterocyclic group having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, such as a heterocyclic group having a hetero atom such as a nitrogen atom, an oxygen atom, or a sulfur atom, such as an imidazolyl group, a pyridyl group, or a quinolyl group; Group, furyl group, piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group and the like), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, More preferably, it is a silyl group having 3 to 24 carbon atoms, and examples thereof include a trimethylsilyl group and a triphenylsilyl group. These substituents may be further substituted with these substituents. Moreover, when it has two or more substituents, they may be the same or different. If possible, they may be bonded to each other to form a ring.

R ¹ , R ² and R ³³ are each independently a hydrogen atom, an alkyl group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), or a group represented by -LQ described later. It is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a chlorine atom, or a group represented by -LQ, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Particularly preferred are a hydrogen atom and an alkyl group having 1 to 2 carbon atoms. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, n-butyl group, sec-butyl group and the like. The alkyl group may have a suitable substituent. Examples of the substituent include a halogen atom, aryl group, heterocyclic group, alkoxyl group, aryloxy group, alkylthio group, arylthio group, acyl group, hydroxyl group, acyloxy group, amino group, alkoxycarbonyl group, acylamino group, oxycarbonyl Group, carbamoyl group, sulfonyl group, sulfamoyl group, sulfonamido group, sulfolyl group, carboxyl group and the like. The carbon number of the alkyl group does not include the carbon atom of the substituent. The same applies to the carbon number of other groups.

L represents a divalent linking group selected from the above linking group group, or a divalent linking group formed by combining two or more thereof. In the linking group group, R ^{b in} —NR ^b — represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and preferably a hydrogen atom or an alkyl group. R ^f in —PO (OR ^f ) — represents an alkyl group, an aryl group or an aralkyl group, and preferably an alkyl group. When R ^b and R ^f represent an alkyl group, an aryl group, or an aralkyl group, the carbon number is the same as that described in the “substituent group”. L preferably contains a single bond, —O—, —CO—, —NR ^b —, —S—, —SO ₂ —, an alkylene group or an arylene group, and —CO—, —O—, —NR ^b- , an alkylene group or an arylene group is particularly preferred. When L includes an alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and still more preferably 1 to 6 carbon atoms. Specific examples of particularly preferable alkylene groups include a methylene group, an ethylene group, a trimethylene group, a tetrabutylene group, and a hexamethylene group. When L contains an arylene group, the carbon number of the arylene group is preferably 6 to 24, more preferably 6 to 18, and still more preferably 6 to 12. Specific examples of particularly preferred arylene groups include phenylene groups and naphthalene groups. When L contains a divalent linking group (that is, an aralkylene group) obtained by combining an alkylene group and an arylene group, the carbon number of the aralkylene group is preferably 7 to 34, more preferably 7 to 26, and still more preferably. 7-16. Specific examples of particularly preferred aralkylene groups include a phenylenemethylene group, a phenyleneethylene group, and a methylenephenylene group. The group listed as L may have a suitable substituent. As such a substituent, the same substituents as those described above as the substituents for R ¹ , R ² and R ³³ can be exemplified.
The specific structure of L is illustrated below.

  In the formula (II), Q is a carboxyl group, a salt of a carboxyl group (for example, lithium salt, sodium salt, potassium salt, ammonium salt (for example, ammonium, tetramethylammonium, trimethyl-2-hydroxyethylammonium, tetrabutylammonium, Trimethylbenzylammonium, dimethylphenylammonium, etc.), pyridinium salts, etc.), sulfo groups, salts of sulfo groups (examples of cations forming the salts are the same as those described above for carboxyl groups), phosphonoxy groups, salts of phosphonoxy groups ( Examples of the cation forming the salt are the same as those described for the carboxyl group). A carboxyl group, a sulfo group, and a phospho group are more preferable, and a carboxyl group or a sulfo group is particularly preferable.

  The fluoropolymer may contain one type of repeating unit represented by the formula (II) or two or more types. Moreover, the said fluorine-type polymer may have 1 type (s) or 2 or more types of repeating units other than said each repeating unit. The other repeating units are not particularly limited, and preferred examples thereof include repeating units derived from ordinary radical polymerizable monomers. Hereinafter, specific examples of monomers for deriving other repeating units will be given. The fluoropolymer may contain a repeating unit derived from one or more monomers selected from the following monomer group.

Monomer group (1) Alkenes Ethylene, propylene, 1-butene, isobutene, 1-hexene, 1-dodecene, 1-octadecene, 1-eicocene, hexafluoropropene, vinylidene fluoride, chlorotrifluoroethylene, 3, 3, 3-trifluoropropylene, tetrafluoroethylene, vinyl chloride, vinylidene chloride and the like;
(2) Dienes 1,3-butadiene, isoprene, 1,3-pentadiene, 2-ethyl-1,3-butadiene, 2-n-propyl-1,3-butadiene, 2,3-dimethyl-1,3 -Butadiene, 2-methyl-1,3-pentadiene, 1-phenyl-1,3-butadiene, 1-α-naphthyl-1,3-butadiene, 1-β-naphthyl-1,3-butadiene, 2-chloro -1,3-butadiene, 1-bromo-1,3-butadiene, 1-chlorobutadiene, 2-fluoro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 1,1,2- Trichloro-1,3-butadiene and 2-cyano-1,3-butadiene, 1,4-divinylcyclohexane and the like;

(3) Derivatives of α, β-unsaturated carboxylic acid (3a) Alkyl acrylates Methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate Amyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, tert-octyl acrylate, dodecyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 2-bromoethyl acrylate, 4-chlorobutyl acrylate, 2-cyanoethyl acrylate, 2-acetoxyethyl acrylate, methoxybenzyl Chryrate, 2-chlorocyclohexyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, 2-methoxyethyl acrylate, ω-methoxypolyethylene glycol acrylate (number of added polyoxyethylene: n = 2 to 100), 3-methoxy Butyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl acrylate, 2- (2-butoxyethoxy) ethyl acrylate, 1-bromo-2-methoxyethyl acrylate, 1,1-dichloro-2-ethoxyethyl acrylate, glycidyl acrylate Such);

(3b) Alkyl methacrylates Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2 -Ethylhexyl methacrylate, n-octyl methacrylate, stearyl methacrylate, benzyl methacrylate, phenyl methacrylate, allyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, cresyl methacrylate, naphthyl methacrylate, 2-methoxyethyl methacrylate, 3-methoxybutyl methacrylate, ω Methoxy polyethylene glycol methacrylate (number of added polyoxyethylene: n = 2 to 100), 2-acetoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2- (2-butoxyethoxy) ethyl methacrylate Glycidyl methacrylate, 3-trimethoxysilylpropyl methacrylate, allyl methacrylate, 2-isocyanatoethyl methacrylate, etc .;

(3c) Diesters of unsaturated polyvalent carboxylic acids Dimethyl maleate, dibutyl maleate, dimethyl itaconate, dibutyl taconate, dibutyl crotonate, dihexyl crotonate, diethyl fumarate, dimethyl fumarate, etc .;

(3d) Amides of α, β-unsaturated carboxylic acids N, N-dimethylacrylamide, N, N-diethylacrylamide, Nn-propylacrylamide, N-tertbutylacrylamide, N-tertoctylmethacrylamide, N- Cyclohexylacrylamide, N-phenylacrylamide, N- (2-acetoacetoxyethyl) acrylamide, N-benzylacrylamide, N-acryloylmorpholine, diacetone acrylamide, N-methylmaleimide and the like;

(4) Unsaturated nitriles Acrylonitrile, methacrylonitrile, etc .;
(5) Styrene and derivatives thereof Styrene, vinyl toluene, ethyl styrene, p-tert butyl styrene, methyl p-vinyl benzoate, α-methyl styrene, p-chloromethyl styrene, vinyl naphthalene, p-methoxy styrene, p-hydroxy Methyl styrene, p-acetoxy styrene, etc .;
(6) Vinyl esters Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl benzoate, vinyl salicylate, vinyl chloroacetate, vinyl methoxyacetate, vinyl vinyl acetate, etc .;

(7) Vinyl ethers Methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, n-dodecyl Vinyl ether, n-eicosyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, fluorobutyl vinyl ether, fluorobutoxyethyl vinyl ether, etc .; and (8) other polymerizable monomers N-vinyl pyrrolidone, methyl vinyl ketone, phenyl vinyl ketone, Methoxyethyl vinyl ketone, 2-vinyl oxazoline, 2-isopropenyl oxazoline, etc.

  In the fluoropolymer, the amount of the fluoroaliphatic group-containing monomer is preferably 5% by mass or more, more preferably 10% by mass or more, and more preferably 30% by mass or more of the total amount of constituent monomers of the polymer. Is more preferable. In the fluoropolymer, the amount of the repeating unit represented by the formula (II) is preferably 0.5% by mass or more of the total amount of constituent monomers of the fluoropolymer, and is 1 to 20% by mass. More preferably, it is 1 to 10% by mass. Since the above-mentioned mass percentage easily varies in a preferable range depending on the molecular weight of the monomer used, the content of the repeating unit represented by the formula (II) is expressed by the number of functional group moles per unit mass of the polymer. Can be defined accurately. When this notation is used, the preferred amount of the hydrophilic group (Q in the formula (II)) contained in the fluoropolymer is 0.1 mmol / g to 10 mmol / g, and the more preferred amount is 0. .2 mmol / g to 8 mmol / g.

  The fluoropolymer has a mass average molecular weight of preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 100,000 or less. The mass average molecular weight can be measured as a value in terms of polystyrene (PS) using gel permeation chromatography (GPC).

  The polymerization method of the fluorine-based polymer is not particularly limited. For example, a polymerization method such as cation polymerization, radical polymerization, or anion polymerization using a vinyl group can be employed. Polymerization is particularly preferred in that it can be used for general purposes. As the polymerization initiator for radical polymerization, known compounds such as radical thermal polymerization initiators and radical photopolymerization initiators can be used, and it is particularly preferable to use radical thermal polymerization initiators. Here, the radical thermal polymerization initiator is a compound that generates radicals by heating to a decomposition temperature or higher. Examples of such radical thermal polymerization initiators include diacyl peroxide (acetyl peroxide, benzoyl peroxide, etc.), ketone peroxide (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), hydroperoxide (hydrogen peroxide, tert. -Butyl hydroperoxide, cumene hydroperoxide, etc.), dialkyl peroxides (di-tert-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxyesters (tert-butyl peroxyacetate, tert -Butyl peroxypivalate, etc.), azo compounds (azobisisobutyronitrile, azobisisovaleronitrile, etc.), persulfates (ammonium persulfate, sodium persulfate) Beam, such as potassium sulphate). Such radical thermal polymerization initiators can be used alone or in combination of two or more.

  The radical polymerization method is not particularly limited, and an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, a solution polymerization method, and the like can be adopted. The solution polymerization, which is a typical radical polymerization method, will be described more specifically. The outlines of other polymerization methods are the same, and details thereof are described, for example, in “Polymer Science Experimental Method” edited by Polymer Society (Tokyo Kagaku Dojin, 1981).

  An organic solvent is used for solution polymerization. These organic solvents can be arbitrarily selected as long as the objects and effects of the present invention are not impaired. These organic solvents are usually organic compounds having boiling points under atmospheric pressure in the range of 50 to 200 ° C., and organic compounds that uniformly dissolve each component are preferred. Examples of preferred organic solvents include alcohols such as isopropanol and butanol; ethers such as dibutyl ether, ethylene glycol dimethyl ether, tetrahydrofuran and dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethyl acetate and acetic acid And esters such as butyl, amyl acetate, and γ-butyrolactone; and aromatic hydrocarbons such as benzene, toluene, and xylene. In addition, these organic solvents can be used individually by 1 type or in combination of 2 or more types. Furthermore, a water-mixed organic solvent in which water is used in combination with the above organic solvent is also applicable from the viewpoint of the solubility of the monomer and the polymer to be produced.

  Also, the solution polymerization conditions are not particularly limited, but for example, it is preferable to heat within a temperature range of 50 to 200 ° C. for 10 minutes to 30 hours. Furthermore, in order not to deactivate the generated radicals, it is preferable to perform an inert gas purge not only during solution polymerization but also before the start of solution polymerization. Usually, nitrogen gas is suitably used as the inert gas.

  In order to obtain the fluoropolymer in a preferable molecular weight range, a radical polymerization method using a chain transfer agent is particularly effective. As chain transfer agents, mercaptans (for example, octyl mercaptan, decyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, octadecyl mercaptan, thiophenol, p-nonylthiophenol, etc.), polyhalogenated alkyls (for example, carbon tetrachloride, Chloroform, 1,1,1-trichloroethane, 1,1,1-tribromooctane, etc.) and low-activity monomers (α-methylstyrene, α-methylstyrene dimer, etc.) can be used, but preferably It is a mercaptan having 4 to 16 carbon atoms. The amount of these chain transfer agents to be used is remarkably influenced by the activity of the chain transfer agent, the combination of the monomers, the polymerization conditions, and the like, and must be precisely controlled. It is about 01 mol% to 50 mol%, more preferably 0.05 mol% to 30 mol%, still more preferably 0.08 mol% to 25 mol%. These chain transfer agents may be present in the system simultaneously with the target monomer whose degree of polymerization is to be controlled in the polymerization process, and the addition method is not particularly limited. It may be added after being dissolved in the monomer, or may be added separately from the monomer.

  The fluorine-based polymer preferably has a polymerizable group as a substituent in order to fix the alignment state of the liquid crystalline compound.

  Specific examples that are preferably used in the present invention as the fluorine-based polymer are shown below, but are not limited to these specific examples. Here, the numerical values (numerical values such as a, b, c, and d) in the formula are mass percentages indicating the composition ratio of each monomer, and Mw is the mass average molecular weight in terms of PEO measured by GPC.

  The said fluoropolymer can be manufactured by a well-known and usual method. For example, it can be produced by adding a general-purpose radical polymerization initiator to an organic solvent containing the above-mentioned fluorine-based monomer, a monomer having a hydrogen bonding group, and the like, and polymerizing it. Further, in some cases, other addition-polymerizable unsaturated compounds can be further added and produced by the same method as described above. Depending on the polymerizability of each monomer, a dropping polymerization method in which a monomer and an initiator are added dropwise to a reaction vessel is also effective for obtaining a polymer having a uniform composition.

  The preferred range of the content of the fluoropolymer in the liquid crystalline composition (liquid crystalline composition excluding the solvent when prepared as a coating liquid) varies depending on the application, but the liquid crystalline composition (coating liquid) In the composition excluding the solvent), it is preferably 0.005 to 8% by mass, more preferably 0.01 to 5% by mass, and 0.05 to 1% by mass. Is more preferable. When the addition amount of the fluorine-based polymer is less than 0.005% by mass, the effect is insufficient. When the addition amount exceeds 8% by mass, the coating film cannot be sufficiently dried or performance as an optical film (for example, retardation). Adverse effects on the uniformity of

Next, the fluorine-containing compound represented by the formula (III) that can be similarly used as the air interface side aligning agent will be described.
Formula (III)
(R ⁰ ) _mo −L ⁰ − (W) _no
In the formula, R ⁰ represents an alkyl group, an alkyl group having a CF ₃ group at the terminal, or an alkyl group having a CF ₂ H group at the terminal, and mo represents an integer of 1 or more. A plurality of R ⁰ may be the same or different, but at least one represents an alkyl group having a CF ₃ group or a CF ₂ H group at the terminal. L ⁰ represents a (mo + no) -valent linking group, W represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or phosphonoxy {—OP (═O) (OH) ₂ } Or a salt thereof, and no represents an integer of 1 or more.

In the formula (III), R ⁰ functions as a hydrophobic group of the fluorine-containing compound. The alkyl group represented by R ⁰ is a substituted or unsubstituted alkyl group, which may be linear or branched, preferably an alkyl group having 1 to 20 carbon atoms, more preferably Is an alkyl group of 4 to 16, particularly preferably an alkyl group of 6 to 16. As the substituent, any of the substituents exemplified as the substituent group D described later can be applied.

The alkyl group having a CF ₃ group at the terminal represented by R ⁰ preferably has 1 to 20 carbon atoms, more preferably 4 to 16 and even more preferably 4 to 8. The alkyl group having a CF ₃ group at the terminal is an alkyl group in which part or all of the hydrogen atoms contained in the alkyl group are substituted with fluorine atoms. 50% or more of hydrogen atoms in the alkyl group are preferably substituted with fluorine atoms, more preferably 60% or more are substituted, and particularly preferably 70% or more are substituted. The remaining hydrogen atoms may be further substituted with the substituents exemplified as the substituent group D described later. The alkyl group having a CF ₂ H group at the terminal represented by R ⁰ preferably has 1 to 20 carbon atoms, more preferably 4 to 16 and even more preferably 4 to 8. The alkyl group having a CF ₂ H group at the terminal is an alkyl group in which some or all of the hydrogen atoms contained in the alkyl group are substituted with fluorine atoms. 50% or more of the hydrogen atoms in the alkyl group are preferably substituted with fluorine atoms, more preferably 60% or more are substituted, and even more preferably 70% or more are substituted. The remaining hydrogen atoms may be further substituted with a substituent exemplified as the substituent group D described later. Examples of an alkyl group having a CF ₃ group at the terminal represented by R ⁰ or an alkyl group having a CF ₂ H group at the terminal are shown below.

R1: n-C ₈ F _{17-
R2: n-C 6 F 13} -
_{R3: n-C 4 F 9} -
_{R4: n-C 8 F 17} - (CH 2) 2 -
_{R5: n-C 6 F 13} - (CH 2) 2 -
_{R6: n-C 4 F 9} - (CH 2) 2 -
_{R7: H- (CF 2) 8} -
_{R8: H- (CF 2) 6} -
_{R9: H- (CF 2) 4} -
_{R10: H- (CF 2) 8} - (CH 2) -
R11: H— (CF ₂ ) ₆ — (CH ₂ ) —
_{R12: H- (CF 2) 4} - (CH 2) -

In the formula (III), the (mo + no) -valent linking group represented by L ⁰ is an alkylene group, an alkenylene group, an aromatic group, a heterocyclic group, —CO—, —NR ^d — (R ^d is the number of carbon atoms) Is preferably a linking group in which at least two groups selected from the group consisting of —O—, —S—, —SO—, and —SO ₂ — are combined.

In the formula (III), W represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof. . The preferred range of W is the same as Q in formula (II).

  Among the fluorine-containing compounds represented by the formula (III), compounds represented by the following formula (III) -a or formula (III) -b are preferable.

In formula (III) -a, R ⁴ and R ⁵ each represents an alkyl group, an alkyl group having a CF ₃ group at the terminal, or an alkyl group having a CF ₂ H group at the terminal, and R ⁴ and R ⁵ are simultaneously It is not an alkyl group. W ¹ and W ² are each a hydrogen atom, a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, phosphonoxy {—OP (═O) (OH) ₂ } or a salt thereof, or An alkyl group, an alkoxy group or an alkylamino group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent is represented, but W ¹ and W ² are not simultaneously hydrogen atoms.

Formula (III) -b
_{^{(R 6 -L 2 -) m2}} (Ar 1) -W 3
In formula (III) -b, R ⁶ represents an alkyl group, an alkyl group having a CF ₃ group at the terminal, or an alkyl group having a CF ₂ H group at the terminal, m2 represents an integer of 1 or more, R ⁶ may be the same or different, but at least one represents an alkyl group having a CF ₃ group or a CF ₂ H group at the terminal. L ² represents an alkylene group, an aromatic group, —CO—, —NR′— (R ′ is an alkyl group having 1 to 5 carbon atoms or a hydrogen atom), —O—, —S—, —SO—, It represents a divalent linking group selected from the group consisting of —SO ₂ — and combinations thereof, and a plurality of L ² may be the same or different. Ar ¹ represents an aromatic hydrocarbon ring or an aromatic heterocycle, W ³ represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof, or an alkyl group, an alkoxy group or an alkylamino group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent.

First, the formula (III) -a will be described.
R ⁴ and R ⁵ are synonymous with R ⁰ in the formula (III), and their preferred ranges are also the same. The carboxyl group (—COOH) or a salt thereof represented by W ¹ and W ² , a sulfo group (—SO ₃ H) or a salt thereof, a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof is It is synonymous with W in Formula (III), and its preferable range is also the same. The alkyl group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent represented by W ^{1 or} W ² may be linear or branched, and preferably has 1 to 20 carbon atoms. It is an alkyl group, More preferably, it is a 1-8 alkyl group, Most preferably, it is a 1-3 alkyl group. The alkyl group having a carboxyl group, a sulfo group, or a phosphonoxy group as the substituent only needs to have at least one carboxyl group, sulfo group, or phosphonoxy group. It is synonymous with the carboxyl group, sulfo group and phosphonoxy group represented by W in formula (III), and the preferred range is also the same. The alkyl group having a carboxyl group, a sulfo group, or a phosphonoxy group as the substituent may be substituted with any other substituent, and the substituent is any of the substituents exemplified as the substituent group D described later. Can be applied. The alkoxy group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent represented by W ¹ and W ² may be linear or branched, and preferably has 1 to 20 carbon atoms. An alkoxy group, more preferably an alkoxy group of 1 to 8, and particularly preferably an alkoxy group of 1 to 4. The alkoxy group having a carboxyl group, a sulfo group, or a phosphonoxy group as the substituent only needs to have at least one carboxyl group, a sulfo group, or a phosphonoxy group. It is synonymous with the carboxyl group, sulfo group and phosphonoxy group represented by W in formula (III), and the preferred range is also the same. The alkoxy group having a carboxyl group, a sulfo group, or a phosphonoxy group may be substituted with other substituents, and any of the substituents exemplified as the substituent group D described later can be applied as the substituent. . The alkylamino group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent represented by W ^{1 or} W ² may be linear or branched, and preferably has 1 to 20 carbon atoms. More preferably 1 to 8 alkylamino groups, and still more preferably 1 to 4 alkylamino groups. The alkylamino group having a carboxyl group, a sulfo group, or a phosphonoxy group may have at least one carboxyl group, a sulfo group, or a phosphonoxy group. Examples of the carboxyl group, the sulfo group, and the phosphonoxy group include the above-described formula ( It is synonymous with the carboxyl group represented by W in III), a sulfo group, and a phosphonoxy group, and its preferable range is also the same. The alkylamino group having a carboxyl group, a sulfo group, or a phosphonoxy group may be substituted with other substituents, and any of the substituents exemplified as Substituent Group D described later is applied as the substituent. it can.

W ¹ and W ² are particularly preferably each a hydrogen atom or (CH ₂ ) _n SO ₃ M (n represents 0 or 1). M represents a cation, but M may not be present when the charge is 0 in the molecule. As the cation represented by M, for example, protonium ion, alkali metal ion (lithium ion, sodium ion, potassium ion, etc.), alkaline earth metal ion (barium ion, calcium ion, etc.), ammonium ion, etc. are preferably applied. . Of these, proton ions, lithium ions, sodium ions, potassium ions, and ammonium ions are particularly preferable.

Next, the formula (III) -b will be described.
R ⁶ has the same meaning as R ⁰ in formula (III) -b, and its preferred range is also the same. L ² is preferably an alkylene group having 1 to 12 carbon atoms, an aromatic group having 6 to 12 carbon atoms, —CO—, —NR—, —O—, —S—, —SO—, —SO ₂ — and Represents a linking group having a total carbon number of 0 to 40 consisting of a combination thereof, more preferably a C 1-8 alkylene group, a phenyl group, —CO—, —NR—, —O—, —S—, —SO ₂ represents a linking group having 0 to 20 carbon atoms and a combination thereof. Ar ¹ preferably represents an aromatic hydrocarbon ring having 6 to 12 carbon atoms, more preferably a benzene ring or a naphthalene ring. As a carboxyl group (—COOH) or a salt thereof represented by W ³ , a sulfo group (—SO ₃ H) or a salt thereof, a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof, or a substituent The alkyl group, alkoxy group, or alkylamino group having a carboxyl group, a sulfo group or a phosphonoxy group is a carboxyl group (—COOH) represented by W ¹ and W ² in the formula (III) -a or a salt thereof, sulfo Group (—SO ₃ H) or a salt thereof, phosphonoxy {—OP (═O) (OH) ₂ } or a salt thereof, or an alkyl group, an alkoxy group, or an alkyl having a carboxyl group, a sulfo group, or a phosphonoxy group as a substituent It is synonymous with an amino group and its preferable range is also the same.

W ³ is preferably a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or a carboxyl group (—COOH) or a salt thereof or a sulfo group (—SO ₃ H) as a substituent. Alternatively, it is an alkylamino group having a salt thereof, and particularly preferably SO ₃ M or CO ₂ M. M represents a cation, but M may not be present when the charge is 0 in the molecule. As the cation represented by M, for example, protonium ion, alkali metal ion (lithium ion, sodium ion, potassium ion, etc.), alkaline earth metal ion (barium ion, calcium ion, etc.), ammonium ion, etc. are preferably applied. . Of these, proton ions, lithium ions, sodium ions, potassium ions, and ammonium ions are particularly preferable.

  In the present specification, the substituent group D includes an alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, such as a methyl group. , Ethyl group, isopropyl group, tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (preferably having 2 carbon atoms) -20, more preferably an alkenyl group having 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, and examples thereof include a vinyl group, an allyl group, a 2-butenyl group, and a 3-pentenyl group), alkynyl A group (preferably an alkynyl group having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, still more preferably 2 to 8 carbon atoms, Argyl group, 3-pentynyl group and the like), an aryl group (preferably an aryl group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and further preferably 6 to 12 carbon atoms). Group, p-methylphenyl group, naphthyl group and the like), substituted or unsubstituted amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, and further preferably 0 to 6 carbon atoms). An amino group, for example, an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, a dibenzylamino group and the like),

An alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, still more preferably 1 to 8 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, and a butoxy group). An aryloxy group (preferably an aryloxy group having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, still more preferably 6 to 12 carbon atoms, and examples thereof include a phenyloxy group and a 2-naphthyloxy group. An acyl group (preferably an acyl group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably 1 to 12 carbon atoms, such as an acetyl group, a benzoyl group, a formyl group, and a pivaloyl group. Etc.), an alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably A C2-C12 alkoxycarbonyl group, for example, a methoxycarbonyl group, an ethoxycarbonyl group, and the like; an aryloxycarbonyl group (preferably having a carbon number of 7-20, more preferably having a carbon number of 7-16, even more preferably Is an aryloxycarbonyl group having 7 to 10 carbon atoms, such as a phenyloxycarbonyl group, and an acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and still more preferably carbon atoms). An acyloxy group having a number of 2 to 10, and examples thereof include an acetoxy group and a benzoyloxy group).

  An acylamino group (preferably an acylamino group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably 2 to 10 carbon atoms, such as an acetylamino group and a benzoylamino group), alkoxycarbonyl An amino group (preferably an alkoxycarbonylamino group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably 2 to 12 carbon atoms, such as a methoxycarbonylamino group), aryloxy Carbonylamino group (preferably an aryloxycarbonylamino group having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, still more preferably 7 to 12 carbon atoms, such as a phenyloxycarbonylamino group) A sulfonylamino group (preferably having 1 to 20 carbon atoms) Preferably it is a C1-C16, More preferably, it is a C1-C12 sulfonylamino group, for example, a methanesulfonylamino group, a benzenesulfonylamino group, etc.), a sulfamoyl group (preferably C0-20). More preferably, it is a sulfamoyl group having 0 to 16 carbon atoms, more preferably 0 to 12 carbon atoms, and examples thereof include a sulfamoyl group, a methylsulfamoyl group, a dimethylsulfamoyl group, and a phenylsulfamoyl group. ), A carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably 1 to 12 carbon atoms, such as an unsubstituted carbamoyl group, a methylcarbamoyl group, or a diethylcarbamoyl group. Group, phenylcarbamoyl group, etc.),

An alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, still more preferably 1 to 12 carbon atoms, such as a methylthio group and an ethylthio group), an arylthio group ( Preferably it is a C6-C20, More preferably, it is a C6-C16, More preferably, it is a C6-C12 arylthio group, For example, a phenylthio group etc. are mentioned, A sulfonyl group (preferably C1-C1). 20, more preferably a sulfonyl group having 1 to 16 carbon atoms, still more preferably 1 to 12 carbon atoms, and examples thereof include a mesyl group and a tosyl group), a sulfinyl group (preferably having a carbon number of 1 to 20, and more. A sulfinyl group having 1 to 16 carbon atoms, more preferably 1 to 12 carbon atoms, is preferable. A ureido group (preferably a benzenesulfinyl group), a ureido group (preferably a ureido group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably 1 to 12 carbon atoms. Ureido group, methylureido group, phenylureido group, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, and further preferably having 1 to 12 carbon atoms) Group such as diethyl phosphoramide group and phenylphosphoric acid amide group), hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group Group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably A heterocyclic group having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, such as a heterocyclic group having a hetero atom such as a nitrogen atom, an oxygen atom, or a sulfur atom, such as an imidazolyl group, a pyridyl group, or a quinolyl group; Group, furyl group, piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group and the like), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, More preferably, it is a silyl group having 3 to 24 carbon atoms, and examples thereof include a trimethylsilyl group and a triphenylsilyl group. These substituents may be further substituted with these substituents. Further, when two or more substituents are present, they may be the same or different. If possible, they may be bonded to each other to form a ring.

  The fluorine-containing compound preferably has a polymerizable group as a substituent in order to fix the alignment state of the liquid crystalline compound.

  Specific examples of the fluorine-containing compound represented by the formula (III) that can be used in the present invention are shown below, but the fluorine-containing compound used in the present invention is not limited thereto.

  The preferable range of the content of the fluorine-containing compound in the liquid crystal composition varies depending on the use, but 0.005 to 0.005 in the liquid crystal composition (a composition excluding the solvent in the case of a coating liquid). The content is preferably 8% by mass, more preferably 0.01 to 5% by mass, and still more preferably 0.05 to 1% by mass.

The optically anisotropic layer 2 is preferably formed using an alignment film. The tilt angle of the liquid crystal compound in the optically anisotropic layer on the alignment film interface side can be controlled by the material of the alignment film used when forming the optically anisotropic layer.
[Alignment film]
Preferred examples of the alignment film that can be used for forming the optically anisotropic layer 2 include neutralizing an organic acid with at least one polyvinyl alcohol polymer, an onium salt, a salt obtained by neutralizing an inorganic acid, and an organic acid. An alignment film containing at least one of a salt or a pyridinium compound obtained in this manner.

(Onium salt)
Examples of onium salts that can be used as the material for the alignment film include quaternary onium salts such as ammonium salts (excluding NH ₄ +) and phosphonium salts. More preferably, it is a compound represented by the following general formula I or II.
First, the compound represented by the general formula I will be described.

Ｍａは窒素原子又はリン原子を表し、Ｒ¹¹、Ｒ¹²、Ｒ¹³、Ｒ¹⁴はそれぞれ、脂肪族基、芳香族基又は複素環基を表し、Ｘ_a ^n-はｎ価のアニオンを表し、ｎは１〜３の整数を表す。

Ma represents a nitrogen atom or a phosphorus ^{atom, R 11, R 12, R} 13, R 14 each represents an aliphatic group, an aromatic group or a heterocyclic group, X _a ^n-represents an n-valent anion, n represents an integer of 1 to 3.

R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each represents an aliphatic group, an aromatic group or a heterocyclic group, and examples of the aliphatic group include an alkyl group, an alkenyl group, an alkynyl group and an aralkyl group. Examples of the group include an aryl group and a heterocyclic group.

(Inorganic acid salt or organic acid salt)
In the formation of the alignment film, a salt obtained by neutralizing an inorganic acid (sometimes referred to as “inorganic acid salt”) or a salt obtained by neutralizing an organic acid (called “organic acid salt”) Can be used). In the present specification, the term “organic acid” is used as a general term for all organic compounds having acidity, and includes not only carboxylic acids but also all acidic organic compounds such as organic sulfonic acids. The counter cation of the inorganic acid salt and the organic acid salt may be an inorganic one such as a metal ion or an organic one such as an alkyl ammonium salt.

The inorganic salt, inorganic acid salt or organic acid salt is preferably a compound represented by MX. M represents a metal ion belonging to Groups 1 to 15 or an ion represented by the following formula III, and X represents an anion.

In the above formula III, R ³¹ , R ³² , R ³³ and R ³⁴ each represent a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and among R ³¹ , R ³² , R ³³ and R ³⁴ At least one is a hydrogen atom.

(Pyridinium compound)
For the formation of the alignment film, a pyridinium compound represented by the following formula IV may be used.

In Formula IV, L ¹ is an alkylene group and —O—, —S—, —CO—, —SO ₂ —, —NRa— (where Ra is an alkyl group having 1 to 5 carbon atoms or a hydrogen atom. And a divalent linking group having 1 to 20 carbon atoms in combination with an alkenylene group, an alkynylene group or an arylene group.

In Formula IV, R ¹ is a hydrogen atom, an unsubstituted amino group, or a substituted amino group having 1 to 20 carbon atoms. When R ¹ is a substituted amino group, it is preferably substituted with an aliphatic group. Aliphatic groups include alkyl groups, substituted alkyl groups, alkenyl groups, substituted alkenyl groups, alkynyl groups and substituted alkynyl groups. When R ¹ is a disubstituted amino group, two aliphatic groups may be bonded to each other to form a nitrogen-containing heterocyclic ring. The nitrogen-containing heterocycle formed at this time is preferably a 5-membered ring or a 6-membered ring. R ¹ is preferably a hydrogen atom, an unsubstituted amino group or a substituted amino group having 1 to 20 carbon atoms, a hydrogen atom, an unsubstituted amino group or a substituted amino group having 2 to 12 carbon atoms. It is particularly preferable that it is a hydrogen atom, an unsubstituted amino group, or a substituted amino group having 2 to 8 carbon atoms. When R ¹ is an amino group, it is preferably substituted at the 4-position of the pyridinium ring.

  In formula IV, X is an anion. Examples of anions include halogen anions (eg, fluorine ions, chlorine ions, bromine ions, iodine ions, etc.), sulfonate ions (eg, methane sulfonate ion, trifluoromethane sulfonate ion, methyl sulfate ion, p-toluene sulfone). Acid ion, p-chlorobenzenesulfonic acid ion, 1,3-benzenedisulfonic acid ion, 1,5-naphthalenedisulfonic acid ion, 2,6-naphthalenedisulfonic acid ion), sulfate ion, carbonate ion, nitrate ion, thiocyanic acid Examples include ions, perchlorate ions, tetrafluoroborate ions, picrate ions, acetate ions, formate ions, trifluoroacetate ions, phosphate ions (for example, hexafluorophosphate ions), and hydroxide ions. X is preferably a halogen anion, a sulfonate ion, or a hydroxide ion.

In Formula IV, Y ¹ is a C 1-30 divalent linking group having a 5- or 6-membered ring as a partial structure. The cyclic partial structure contained in Y ¹ is particularly preferably a cyclohexyl ring, an aromatic ring or a heterocyclic ring. Examples of the aromatic ring include a benzene ring, an indene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring, an anthracene ring, a biphenyl ring, and a pyrene ring. A benzene ring, a biphenyl ring, and a naphthalene ring are particularly preferable. The hetero atom constituting the hetero ring is preferably a nitrogen atom, an oxygen atom or a sulfur atom. For example, a furan ring, thiophene ring, pyrrole ring, pyrroline ring, pyrrolidine ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole Ring, imidazole ring, imidazoline ring, imidazolidine ring, pyrazole ring, pyrazoline ring, pyrazolidine ring, triazole ring, furazane ring, tetrazole ring, pyran ring, dioxane ring, dithiane ring, thiine ring, pyridine ring, piperidine ring, oxazine ring Morpholine ring, thiazine ring, pyridazine ring, pyrimidine ring, pyrazine ring, piperazine ring and triazine ring. The heterocycle is preferably a 6-membered ring. The divalent linking group having a 5- or 6-membered ring represented by Y as a partial structure may have a substituent.

In Formula IV, Z is halogen-substituted phenyl, nitro-substituted phenyl, cyano-substituted phenyl, phenyl substituted with an alkyl group having 1 to 10 carbon atoms, or phenyl substituted with an alkoxy group having 2 to 10 carbon atoms. An alkyl group having 1 to 12 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, and the number of carbon atoms 7-26 aryloxycarbonyl group, arylcarbonyloxy group having 7-26 carbon atoms, cyano-substituted phenyl, halogen-substituted phenyl, phenyl substituted by alkyl group having 1-10 carbon atoms, carbon atom Phenyl substituted by an alkoxy group having 2 to 10 carbon atoms, an aryloxycarbonyl group having 7 to 26 carbon atoms, or a carbon atom number Arylcarbonyloxy group to 26 is preferred.
Z may further have a substituent, and examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), a cyano group, a nitro group, and a carbon atom number of 1 to 16. An alkyl group having 1 to 16 carbon atoms, an alkynyl group having 1 to 16 carbon atoms, a halogen-substituted alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, An acyl group having 2 to 16 carbon atoms, an alkylthio group having 1 to 16 carbon atoms, an acyloxy group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, a carbamoyl group, a carbon atom An alkyl-substituted carbamoyl group having 2 to 16 carbon atoms and an acylamino group having 2 to 16 carbon atoms are included.

2. Optically anisotropic layer 1
The optically anisotropic layer 1 is an optically anisotropic layer having an in-plane retardation at a wavelength of 550 nm of 50 to 300 nm and a retardation in the thickness direction of 50 to 250 nm. As long as the above characteristics are satisfied, the material of the optically anisotropic layer is not particularly limited. When the optically anisotropic layer 1 is made of a polymer film, it can be used as a support for the optically anisotropic layer 2 and can also be used as a protective film for a polarizer. Examples of the polymer film that can be used as the optically anisotropic layer 1 include films of cellulose ester, polyester, polycarbonate, cycloolefin polymer, vinyl polymer, polyamide, polyimide, and the like.
These polymers may be used alone or in combination of two or more polymers.

[Cellulose acylate]
An example of a polymer film that can be used as the optically anisotropic layer 1 is a cellulose acylate film.
When a cellulose acylate film is used for the optically anisotropic layer 1, the acyl substituent of the cellulose acylate used as the material thereof may be a cellulose acylate composed of an acetyl group alone, for example, a plurality of acyl substituents. You may use the composition containing the cellulose acylate which has this. The cellulose acylate preferably has a total substitution degree of 2.7 to 3.0 in order to impart negative intrinsic birefringence. The negative intrinsic birefringence here means a property having a direction having a maximum value of the refractive index in a direction orthogonal to the stretching direction when the polymer film is stretched. In the present invention, it is preferable to achieve the necessary negative intrinsic birefringence through the acyl substitution degree and the stretching or crystallization treatment step described below.

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 expression of the cellulose acylate film and the humidity dependence of the retardation. In addition, Tc can be adjusted, whereby the high volatile crystallization temperature can be adjusted. The humidity dependency of retardation is a reversible change in retardation due to humidity.
SA + SB is appropriately adjusted depending on the optical properties required for the cellulose acylate film, but preferably 2.70 ≦ SA + SB ≦ 3.00, more preferably 2.88 ≦ SA + SB ≦ 3.00, and even more preferably. 2.89 ≦ SA + SB ≦ 2.99, even more preferably 2.90 ≦ SA + SB ≦ 2.98, and particularly preferably 2.92 ≦ SA + SB ≦ 2.97. By increasing SA + SB, Re obtained after highly volatile crystallization treatment can be increased, Tc can be lowered, and the humidity dependency of retardation can also be improved. By setting Tc low, the high volatile crystallization temperature can be set relatively low.
Moreover, the humidity dependence of the retardation of the cellulose acylate 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 particularly preferably SB = 0. When all the hydroxyl groups of cellulose are substituted, the degree of substitution is 3.

Cellulose acylate can be synthesized by a known method.
For example, the basic principle of the cellulose acylate synthesis method is described in Nobuhiko Ueda et al., Wood Chemistry pages 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 degree of acyl substitution at the 3rd, 6th and 6th positions 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 stoichiometric excess amount relative to the total amount of cellulose reacting with the carboxylic acid anhydride and moisture present in the system.

The polymer film used as the optically anisotropic layer 1 can be produced from a polymer solution containing a polymer and various additives by a solution casting film forming method.
Further, when the melting point of the polymer or the melting point of the mixture of the polymer and various additives is lower than the decomposition temperature and higher than the stretching temperature described later, it is prepared by film formation by a melt film forming method. You can also. The melt film forming method is described in JP-A No. 2000-352620.
JP-A-2001-151901 describes a solvent and a plasticizer that can be suitably used when a cellulose acylate film is used. Moreover, about an infrared absorber, Unexamined-Japanese-Patent No. 2001-194522 has description. The timing of adding the additive can be appropriately determined according to the type of the additive.

  The polymer solution can be prepared by, for example, JP-A-58-127737, JP-A-61-106628, JP-A-2-276830, JP-A-4-259511, JP-A-5-163301, and 9- No. 95544, No. 10-45950, No. 10-95854, No. 11-71463, No. 11-302388, No. 11-322946, No. 11-322947, No. 11-323017 No. 2000, 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 film can be produced using various solution casting film forming apparatuses in accordance with various solution casting film forming methods. 0-2 mass% is preferable, and, as for the residual solvent amount in the film obtained through a drying process, More preferably, it is 0-1 mass%. The obtained film may be conveyed as it is to the stretching zone or the heat treatment zone, or may be stretched or heat treated off-line after winding the film.

(Stretching)
In order to obtain a polymer film satisfying the characteristics required for the optically anisotropic layer 1, a stretching treatment may be performed after the film formation.
The stretching treatment may be, for example, longitudinal stretching performed in the transport direction between two or more apparatuses (for example, nip rolls or suction drums) that hold the film whose peripheral speed on the exit side is increased in the transport direction, but preferably is stretched The direction is transverse stretching performed in a direction orthogonal to the transport direction, and for example, tenter stretching is preferably performed in an apparatus having a heating zone by gripping both ends of the film with a tenter clip. The draw ratio can be appropriately set according to the retardation required for the film, preferably 1 to 500%, more preferably 3 to 400%, still more preferably 5 to 300%, and particularly preferably 10 to 100%. These stretching operations may be performed in one stage or in multiple stages. Here, “stretch ratio (%)” means that obtained by the following formula.
Stretch ratio (%) = 100 × {(Length after stretching) − (Length before stretching)} / Length before stretching The stretching speed in the stretching is preferably 10 to 10,000% / min, more preferably 20 It is -1000% / min, More preferably, it is 30-800% / min.

(Heat treatment)
In order to produce a polymer film that satisfies the characteristics required for the optically anisotropic layer 1, it is preferable to heat-treat the polymer film thus formed in addition to the stretching treatment. The heat treatment is preferably performed before the stretching treatment, and the stretching treatment can be performed simultaneously with the heat treatment. It is preferable that the film is once cooled after the heat treatment and further subjected to a stretching treatment.

The heat treatment temperature is preferably (Tg + 60) ° C. or more, more preferably (Tg + 60) to (Tg + 180) ° C., still more preferably (Tg + 65) to (Tg + 150) ° C., and particularly preferably (Tg + 70) to (Tg + 100) ° C. More specifically, in the cellulose acylate film, the heat treatment temperature is preferably 200 ° C. or higher, more preferably 200 to 280 ° C., further preferably 210 to 270 ° C., and particularly preferably 220 to 250. ° C.
The cooling temperature is preferably 50 ° C. or more lower than the heat treatment temperature, more preferably 100 to 300 ° C., and further preferably 150 to 250 ° C.
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., particularly preferably 50 to 100 ° C., and the stretching temperature is the heat treatment temperature. Lower is preferred.
Here, the above-mentioned Tg is the glass transition temperature of the film formed into a solution, and 20 mg of the sample before heat treatment is put into a DSC measurement pan, and this is added from 30 ° C. at 10 ° C./min in a nitrogen stream. The temperature was raised to 120 ° C., held for 15 minutes, and then cooled to 30 ° C. at −20 ° C./min. Thereafter, the temperature is raised again from 30 ° C. to 250 ° C., and the temperature at which the baseline starts to deviate from the low temperature side is defined as Tg of the film.

The heat treatment is preferably carried out while transporting the film into a heating zone maintained at the temperature. In this case, it is preferably performed while heating between two or more apparatuses (for example, nip rolls or suction drums) held in the transport direction, and may be performed in an apparatus having a heating zone between nip rolls, for example.
In addition, it may be carried out with or without carrying out the difference between the peripheral speeds on the inlet side and the outlet side. When the circumferential speed is made different, the film elongation is controlled to 3 to 500%. It is preferably 5 to 100%, more preferably 10 to 80%, and particularly preferably 20 to 60%. The “elongation (%) of the film” here means a value obtained by using the following formula.
Elongation of film (%) = 100 × {(length after heat treatment) − (length before heat treatment)} / length before heat treatment

An example of a method for producing a cellulose acylate film that can be used as the optically anisotropic layer 1 in the present invention includes a casting step of casting a polymer solution containing at least one cellulose acylate to form a web, While the amount of residual solvent is 100 to 300% by mass, the web formed in the casting process is stretched by 5 to 100% in the transport direction, and the web is dried at a film surface temperature of 50 to 150 ° C. And a manufacturing process in which the starting residual volatile content of the drying process is 10 to 150% by mass and the final residual volatile content is 10 to 50% by mass.
According to this method, a cellulose acylate film that satisfies the characteristics required for the optically anisotropic layer 1 can be stably produced.

  The polymer film used as the optically anisotropic layer 1 preferably has a single layer structure. Here, the “single layer structure” film does not mean that a plurality of film materials are bonded together, but means a single polymer film. And it includes the case where a single polymer film is produced from a plurality of polymer solutions using a sequential casting method or a co-casting method. In this case, a polymer film having a distribution in the thickness direction can be obtained by appropriately adjusting the type and blending amount of the additive, the molecular weight distribution of the polymer, the type of polymer, and the like. Moreover, what has various functional parts, such as an optical anisotropy part, a glare-proof part, a gas barrier part, and a moisture-resistant part, in those one film is also included.

Web filming:
First, a web is formed. It can be formed by a solution casting film forming method using a polymer solution. In carrying out the solution casting film forming method, a known apparatus can be used according to a conventional method. Specifically, a dope (also referred to as a polymer solution) prepared in a dissolving machine (kettle) is filtered and temporarily stored in a storage kettle, and the foam contained in the dope is 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 number of rotations. It casts uniformly on the metal support body of the casting part which has been (dope casting process). Next, at the peeling point where the metal support has almost gone around, the dough film (web) which has been dried is peeled from the metal support, 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.
A metal band or a metal drum can be used as the metal support used in the film formation of the web.

WET stretching process:
In the method for producing a cellulose acylate film, in the stretching step, the web formed in the casting step is stretched in the transport direction while being transported. Under the present circumstances, the residual solvent amount at the time of the extending | stretching start of a web is 150-300 mass%.

Residual solvent amount:
The residual solvent amount of the cellulose acylate web at the start of stretching can be calculated based on the following formula.
Residual solvent amount (% by mass) = {(MN) / N} × 100
[In the formula, M is the mass of the cellulose acylate film just before being inserted into the stretching zone, and N is the mass when the cellulose acylate film just before being inserted into the stretching zone is dried at 120 ° C. for 2 hours. To express]

  In the stretching step, the residual solvent amount at the start of stretching of the web is 150 to 300% by mass, and 200 to 300% by mass is further considered in consideration of the balance of stripping, web judgment, stretching temperature, stretching ratio, and the like. preferable. If the residual solvent amount is less than 150% by mass, the web is likely to break during stretching if the stretching temperature is lowered. For this reason, it is necessary to set high extending | stretching temperature, and energy efficiency will fall. Even if the stretching temperature is increased, the web will still be broken if stretched at a high magnification. Furthermore, when the residual solvent amount is less than 150% by mass, the stretch ratio is lowered, and the desired optical characteristics cannot be obtained. On the other hand, if the residual solvent amount exceeds 300% by mass, the web peelability, stretching suitability (wrinkles, handling, etc.), and recoverability are significantly reduced. In particular, when the amount of the residual solvent is in the range of 200 to 300% by mass, it is easy to increase the draw ratio, and furthermore, it is possible to more effectively suppress web breakage.

  The residual solvent amount of the cellulose acylate 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.

In the stretching step, the web is stretched in the transport direction while being transported. At this time, the stretch ratio of the web is preferably 5 to 100% and more preferably 15 to 50% from the viewpoint of preventing the web from being broken while achieving a high stretch ratio. The stretch ratio (elongation) of the cellulose acylate web during the stretching can be achieved by the difference in peripheral speed between the metal support speed and the stripping speed (stripping roll draw). For example, when an apparatus having two nip rolls is used, the cellulose acylate film is preferably stretched in the transport direction (longitudinal direction) by increasing the rotational speed of the nip roll on the outlet side rather than the rotational speed of the nip roll on the inlet side. can do. By performing such stretching, the expression of retardation can be adjusted.
Here, the “stretch ratio (%)” means that obtained by the following formula.
Stretch ratio (%) = 100 × {(Length after stretching) − (Length before stretching)} / Length before stretching

  In the stretching step, the film surface temperature (stretching temperature) of the web during stretching is not particularly limited, but is preferably 30 ° C. or less from the viewpoint of reducing the stretching efficiency and the change in volatile content. Further, the web stretching speed in the stretching step is not particularly limited, but is preferably 1 to 1000% / min, and more preferably 1 to 100% / min from the viewpoint of proper stretching (wrinkle, handling, etc.). . Stretching may be performed in one stage or in multiple stages. Further, stretching may be applied in a direction (lateral direction) perpendicular to the transport direction.

  The web that has undergone the stretching process is then conveyed to a drying (crystallization) process. In the drying process, the web is dried while both ends are fixed with clips and pins with a tenter.

Drying (crystallization) treatment process:
The web having been subjected to the stretching treatment is treated in a step of drying the film at an average film surface temperature of 30 to 150 ° C. in the range of 10 to 150% by mass, preferably 10 to 100% by mass of the residual residual volatile content in the drying process (crystallization) processing).
The crystallization treatment step is preferably performed while conveying the cellulose acylate film (web). The means for transporting the cellulose acylate film is not particularly limited, but typical examples include means for transporting by a nip roll or a suction drum, means for transporting while gripping with a tenter clip (means for transporting by air pressure), and the like. . Preferred is a means for conveying while being fixed with a pin-shaped tenter and a means for conveying with a plurality of conveying rollers having a narrow gap, and more preferable is a means for conveying while being fixed with a pin-shaped tenter, It is a means to convey with a conveyance roller.

Specifically, the means for transporting while fixing with a pin-shaped tenter is as follows. Specifically, both ends of the cellulose acylate film on the line orthogonal to the transport direction are fixed with a pin-shaped tenter, and the tenter with one end fixed and the other It can carry out by conveying, controlling the distance between the tenter which fixed the edge part of this. The distance between the tenters can be controlled by appropriately setting the tenter rail pattern. In this manner, by controlling the distance between the tenters, the cellulose acylate film can be dried while suppressing the dimensional change rate in the width direction to a desired value.
In order to prevent web breakage, wrinkling, and conveyance failure, it is preferable to increase the inner pin density and decrease the outer pin density in the pins of the pin tenter.

  Specifically, the means for transporting by a plurality of transport rollers having a narrow gap is cellulose on a plurality of transport rolls installed in the crystallization treatment zone so that the clearance between adjacent transport rolls is 0.1 cm to 50 cm. It can carry out by conveying through an acylate film. The gap between adjacent transport rolls refers to the distance between the transported film being separated from one transport roll and being wrapped by the next transport roll. By passing between a group of conveyance rolls (so-called dense rolls) with a narrow gap between such conveyance rolls, the holding force by the conveyance rolls acts in the film width direction, and the dimensional change rate in the film width direction is suppressed. can do. In this method, widening in the width direction as in the tenter clip method is impossible, but shrinkage can be minimized.

  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 crystal growth can fully be advanced with a practical crystallization process zone length. If the conveyance speed is increased, the coloration of the film tends to be suppressed, and if the conveyance speed is decreased, the crystallization treatment zone length tends to be shortened. It is preferable to keep the conveyance speed during the crystallization process (the speed of devices such as a nip roll and a suction drum that determine the conveyance speed) constant.

In order to prevent foaming of the web itself and adhesion of the web to the holding means in the tenter, in the tenter drying device, the both-side edge holding pins of the web are cooled to below the foaming temperature of the web by a blow type cooler, It is preferable to cool the pin immediately before biting the web to below 0 ° C of the dope in the duct type cooler.
As a crystallization treatment method, for example, a method in which a cellulose acylate film is passed through a zone at a temperature T, a method in which hot air is applied to the cellulose acylate film being transported, and a heat ray is applied to the cellulose acylate film being transported. And a method of bringing a cellulose acylate film into contact with a heated roll.

  Preferably, the cellulose acylate film is passed through a zone having a temperature T while hot air is being conveyed. This method has an advantage that the cellulose acylate 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 cellulose acylate film in the zone of temperature T varies depending on the properties and transport speed of the cellulose acylate film to be manufactured, but usually (transport length) / (width of the cellulose acylate film to be transported). The ratio is preferably set to be 0.1 to 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 passing time (crystallization 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.

In order to prevent deterioration in quality such as flatness when the speed is increased by the solution casting method or the width of the web is widened by the tenter, the wind speed is set to 0 when the web is dried in the tenter. An invention is described in which the temperature distribution in the transverse direction is 10% or less, and the web up-and-down airflow ratio is 0.2 to 1.
When the wind speed distribution on the film surface located in the direction in which the dry gas is blown out is based on the upper limit of the wind speed, the difference between the upper limit and the lower limit is within 20% of the upper limit, and the dry gas is blown out. It is preferable to dry the web.

In the manufacturing method, in order to adjust Re and Rth, the volatile matter may be stretched or shrunk in the direction perpendicular to the conveying direction while the volatile content is 300 to 10%. Stretching can reduce Re and increase Rth, and shrinkage can increase Re and reduce Rth.
Further, the cellulose acylate film can be stretched in the direction orthogonal to the transport direction during the crystallization treatment, whereby the slow axis direction can be adjusted (homogenized) and the surface shape can be improved.

For example, it can be carried out by fixing both ends of a cellulose acylate film with a pin-shaped tenter and passing it through a heating zone while stretching or shrinking in a direction (lateral direction) perpendicular to the transport direction.
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.
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%. The shrinkage in the width direction can be obtained from the following equation by measuring the full width immediately before and after the film shrinks.
Shrinkage rate (%) in the width direction = 100 × (full width immediately before shrinkage−full width immediately after shrinkage) / full width just before shrinkage

The crystallization treatment process may be performed only once or a plurality of times. Performing a plurality of times means that the crystallization process is performed while the temperature is again set to be higher than Tc and lower than Tm ₀ after the previous crystallization process is completed. When performing the crystallization process a plurality of times, it is preferable to satisfy the above-mentioned range of the draw ratio when all the crystallization processes are completed. The crystallization treatment in the production method is preferably 3 times or less, more preferably 2 times or less, and most preferably 1 time.

Multi-layer casting:
The cellulose acylate solution may be cast as a single layer liquid on a smooth band or drum as a metal support, or a plurality of cellulose acylate liquids of two or more layers may be cast. When casting a plurality of cellulose acylate solutions, produce a film while casting and laminating a solution containing cellulose acylate from a plurality of casting openings provided at intervals in the traveling direction of the metal support. For example, the methods described in JP-A-61-158414, JP-A-1-122419, and JP-A-11-198285 can be applied.
Further, it may be formed into a film by casting a cellulose acylate solution from two casting ports. For example, JP-B-60-27562, JP-A-61-94724, JP-A-61-947245, It can be carried out by the methods described in JP-A Nos. 61-104813, 61-158413, and 6-134933. Further, a cellulose acylate film in which a flow of a high-viscosity cellulose acylate solution described in JP-A-56-162617 is wrapped with a low-viscosity cellulose acylate solution and the high- and low-viscosity cellulose acylate solutions are simultaneously extruded. A casting method may be used. Furthermore, it is also a preferred embodiment that the outer solution described in JP-A-61-94724 and JP-A-61-94725 contains a larger amount of an alcohol component which is a poor solvent than the inner solution. Alternatively, the film is formed by peeling the film formed on the metal support using the first casting port and performing the second casting on the side in contact with the metal support surface using the two casting ports. For example, it is a method described in Japanese Patent Publication No. 44-20235. The cellulose acylate solutions to be cast may be the same solution or different cellulose acylate solutions, and are not particularly limited. In order to give a function to a plurality of cellulose acylate layers, a cellulose acylate solution corresponding to the function may be extruded from each casting port. Furthermore, the cellulose acylate solution can be cast by simultaneously casting other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, a polarizing layer).

In the conventional single-layer liquid, it is necessary to extrude a high-concentration and high-viscosity cellulose acylate solution in order to obtain the required film thickness. In many cases, this causes a problem such as a fault or flatness. As a solution to this, by casting a plurality of cellulose acylate solutions from a casting port, a highly viscous solution can be extruded onto a metal support at the same time. Not only can it be produced, but also a concentrated cellulose acylate solution can be used to reduce the drying load and increase the film production speed.
In the case of co-casting, the inner and outer thicknesses are not particularly limited, but preferably the outer side is preferably 1 to 50% of the total film thickness, and more preferably 2 to 30%. Here, in the case of co-casting with three or more layers, the total thickness of the layer in contact with the metal support and the layer in contact with the air side is defined as the outer thickness. In the case of co-casting, a cellulose acylate film having a laminated structure can be produced by co-casting cellulose acylate solutions having different additive concentrations such as the above-mentioned plasticizer, ultraviolet absorber and matting agent. For example, a cellulose acylate film having a structure of skin layer / core layer / skin layer can be produced. For example, the matting agent can be contained in the skin layer in a large amount or only in the skin layer. The plasticizer and the ultraviolet absorber can be contained in the core layer more than the skin layer, and may be contained only in the core layer. In addition, the type of plasticizer and ultraviolet absorber can be changed between the core layer and the skin layer. For example, the skin layer contains a low-volatile plasticizer and / or an ultraviolet absorber, and the core layer has excellent plasticity. It is also possible to add a plasticizer or an ultraviolet absorber excellent in ultraviolet absorption. Moreover, it is also a preferable aspect to contain a peeling accelerator only in the skin layer on the metal support side. It is also preferable to add more alcohol, which is a poor solvent, to the skin layer than the core layer in order to cool the metal support by the cooling drum method to gel the solution. The Tg of the skin layer and the core layer may be different, and the Tg of the core layer is preferably lower than the Tg of the skin layer. Further, the viscosity of the solution containing cellulose acylate during casting may be different between the skin layer and the core layer, and the viscosity of the skin layer is preferably smaller than the viscosity of the core layer. It may be smaller than the viscosity.

Stretching (restretching) with a volatile content of 30 to 1%:
In the production method, stretching may be performed after the crystallization treatment of the cellulose acylate film (referred to as “re-stretching” in order to distinguish from other stretching). At this time, the re-stretching can effectively reduce the humidity dependency of the retardation (particularly Re) of the finally obtained transparent film. The redrawing temperature is more preferably 60 to 200 ° C, and further preferably 80 to 150 ° C.

  By carrying out the redrawing, it is considered that the oriented amorphous part can be reduced without largely moving the crystal part. Therefore, it is possible to reduce the humidity dependence of Re without greatly moving Re, and to control chromatic dispersion. Such re-stretching is preferably performed in the direction perpendicular to the transport direction from the viewpoint of efficiently reducing the oriented amorphous portion.

Here, the wavelength dispersion of the obtained film can be adjusted by performing stretching after the heat treatment. The wavelength dispersion of the film is mainly determined by the orientation of the amorphous part and the additive (wavelength dispersion adjusting agent). On the other hand, the direction of the slow axis of the film and the absolute values of Re and Rth are mainly determined by the orientation of the crystal part. Here, when examining the orientation direction before (re) stretching of the film, in the film that was only heat-treated (preliminary stretching was not performed), the crystal part, the amorphous part, and the additive were transported during the heat-treatment step. In the film oriented in the direction and subjected to prestretching and heat treatment, the crystal part, the amorphous part and the additive are oriented in the prestretching direction. The film after these heat treatment steps is preferably stretched within the specific range, which means that in the stretching after the heat treatment, the change rate of the orientation of the amorphous part and the additive is faster than the orientation of the crystal part. based on. That is, the orientation of the amorphous part or the like can be changed dominantly without greatly moving the crystal part. According to the production method, the orientation of the amorphous part and the additive can be brought into a state orthogonal to the orientation of the crystal part by stretching after the heat treatment step, and the wavelength dispersion can be freely performed without changing the direction of the slow axis. It becomes possible to control.
Stretching is performed after heat treatment of the cellulose acylate film (referred to as “re-stretching” to distinguish from other stretching). At this time, the wavelength dispersion of the optical compensation film finally obtained can be effectively controlled by redrawing at (Tg-20) to (Tg + 50) ° C. The redrawing temperature is more preferably (Tg-10) to (Tg + 40) ° C, and further preferably Tg to (Tg + 30) ° C. Here, Tg represents the glass transition temperature (unit: ° C.) of the cellulose acylate film before heat treatment.

The re-stretching may be performed after the cellulose acylate film is cooled to a temperature of Tg ₀ or less after the crystallization treatment, or may be performed without being cooled while maintaining the crystallization treatment temperature. Once the polymer film is cooled, the cooling may be naturally allowed to cool to a temperature of Tg ₀ or lower, or may be forced to cool to a temperature of Tg ₀ or lower. Further, it may be in a state where it is once cooled and then heated to Tg ₀ or less again. The cooling temperature when the film is once cooled is preferably 50 ° C. or more lower than the crystallization treatment temperature, more preferably 100 to 300 ° C., and further preferably 150 to 250 ° C. There is a tendency that the Rth / Re value of the film after the crystallization treatment can be easily controlled by lowering the cooling temperature by 50 ° C. or more than the crystallization treatment temperature. In addition, it is preferable that the film is once cooled to a cooling temperature and then re-stretched after being heated again to a temperature lower than Tc. The difference between the crystallization treatment temperature and the redrawing 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 this temperature difference, the Rth / Re value can be controlled. Specifically, if the difference between the crystallization temperature and the redrawing 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 re-stretching method, the method described in the description of the stretching during the crystallization process can be employed. Re-stretching may be performed in one stage or in multiple stages. Preferably, there are a method of stretching in the conveying direction by changing the rotation 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 conveying direction. Particularly preferably, stretching is not performed during the highly volatile crystallization process, or stretching is performed in the transport direction by changing the rotation speed of the nip roll, and both ends of the polymer film are held with tenter clips after the crystallization process. This is a mode of re-stretching by spreading in the direction perpendicular to the conveying direction.

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

By performing re-stretching after the crystallization treatment, Re and Rth of the obtained transparent film can be adjusted. For example, by increasing the stretching temperature for re-stretching, Rth can be lowered without changing Re much. Moreover, Re can be reduced and Rth can be increased by increasing the draw ratio of re-stretching. Since these show a substantially linear correlation, it becomes easy to achieve the target Re and Rth by appropriately selecting the stretching conditions for re-stretching.
After the crystallization treatment is finished, Re and Rth of the cellulose acylate film in a state before re-stretching are not particularly limited.

Post-drying and handling:
The drying temperature in the drying step after the film is peeled from the support or after the tenter is preferably 40 to 250 ° C, particularly preferably 70 to 180 ° C. Further, in order to remove the residual solvent, it is preferably used that it is dried at 50 to 160 ° C., and in that case, the residual solvent is evaporated by drying with high-temperature air whose temperature is changed successively. The above method is described in Japanese Patent Publication No. 5-17844. The drying temperature, the amount of drying air, and the drying time vary depending on the solvent used, and may be appropriately selected according to the type and combination of the solvents used. The amount of residual solvent in the final finished film is preferably 2% by mass or less, and more preferably 0.4% by mass or less in order to obtain a film having good dimensional stability.

  Regarding the residual solvent amount of the film after drying, Japanese Patent Application Laid-Open No. 2002-241511 discloses that even a thin film of 20 to 60 μm eliminates deformation over time, is optically isotropic, and has no scratches. For the purpose of eliminating bubbles and undissolved materials without causing any problems, an invention is described in which the amount of residual solvent during winding is 0.05% by mass or less. As a more preferred embodiment, the difference between the maximum value and the minimum value of the residual solvent amount in the width direction is 0.02% by mass or less. The residual solvent amount is preferably 0.04% by mass or less, particularly preferably 0. It is disclosed that the content is 0.02% by mass or less, and that the drying temperature is 100 to 200 ° C. and the drying time is 5 to 30 minutes.

  Moreover, in order to reduce stable conveyance, surface improvement, necessary optical characteristics, and heat shrinkage, Japanese Patent Application Laid-Open No. 2003-053751 describes residual volatile content (dry basis) in the base at the time of drying as 3-7. An invention is described in which the poor solvent ratio in the residual volatile matter is 0.01 to 95 mass% when the mass is mass%.

  Japanese Patent Application Laid-Open No. 2003-071863, which is an invention for obtaining a film that does not cause fogging, further dried the film peeled off from the belt in the film drying step, and the residual solvent amount was 0.5% by mass. It is described below that it is preferably 0.1% by mass or less, and most preferably 0 to 0.01% by mass or less.

  In addition, in Japanese Patent Application Laid-Open No. H5-278051, a solute is selected so that the interaction parameter χ between the solute and the polymer is 0.9 or less for the purpose of physical properties with excellent productivity and little difference between the front and back of the solute. And an invention of a solution casting method in which drying until the weight ratio of the solvent to the polymer in the cast film becomes 23% or less is maintained while maintaining the weight ratio of the surface of the film to the polymer of the solvent at 12% or more. Are listed.

  The matters described in each of the above publications can be applied to the present invention.

  These steps from casting to post-drying may be performed in an air atmosphere or an inert gas atmosphere such as nitrogen gas. For drying, far-infrared rays or microwaves may be used as described in JP-A-8-134336, JP-A-8-259706, and JP-A-8-325388.

  Japanese Patent Laid-Open No. 2002-283370 discloses that a film cleaning device is arranged before introduction into a drying device or a heat straightening device and / or after carrying out to remove dust adhering to the web. Are listed. As the cleaning means, methods other than the vibration / high-pressure air supply / suction method, such as a method of performing flame treatment (corona treatment, plasma treatment), a method of installing an adhesive roll, and the like are disclosed. In addition, as a preferable mode for preventing further foreign matter from being mixed, the installation of a static eliminator at a position where it is wound in the winding source winding tangent, the static eliminator has a charging potential of <5 A configuration in which a reverse potential is applied by a static elimination device or a forced charging device at the time of winding so as to be ± 2 KV. A configuration in which static elimination is performed by a static elimination device in which the forced charging potential is alternately converted between positive and negative at 1 to 150 Hz. The use of an ionizer or a charge removal bar that generates an ionic wind is disclosed.

[Low substituted cellulose acylate]
An example of the polymer film that can be used as the optically anisotropic layer 1 is a low-substituted cellulose acylate-based film having a low-substituted layer containing a cellulose acylate satisfying the following formula (I) as a main component.
(1) 2.0 <Z1 <2.7
(In formula (1), Z1 represents the total acyl substitution degree of the cellulose acylate of the low substitution degree layer.)
In the present specification, “containing as a main component” means an ingredient having the highest mass fraction in an embodiment in which the component as a raw material is one kind, and an ingredient having two or more ingredients. To do.

The low substitution layer may have a high substitution layer containing, as a main component, cellulose acylate satisfying the following formula (2) on at least one surface thereof.
(2) 2.7 <Z2
(In Formula (2), Z2 represents the total acyl substitution degree of the cellulose acylate in the high substitution degree layer.)

  Examples of the cellulose acylate used for the production of the low-substituted cellulose acylate film include cotton linter and wood pulp (hardwood pulp, conifer pulp), and cellulose acylate obtained from any raw material cellulose can also be used. You may mix and use depending on the case. Detailed descriptions of these raw material celluloses can be found in, for example, Marusawa and Uda, “Plastic Materials Course (17) Fibrous Resin”, published by Nikkan Kogyo Shimbun (published in 1970), and the Japan Society of Invention and Innovation Technical Bulletin No. 2001. The cellulose described in No.-1745 (pages 7 to 8) can be used.

  The raw material cellulose acylate used for the production of the low-substituted cellulose acylate film is acylated with two or more types of acyl groups, even if it is acylated with one type of acyl group. May be. It is preferable to have an acyl group having 2 to 4 carbon atoms as a substituent. When two or more types of acyl groups are used, one of them is preferably an acetyl group, and the acyl group having 2 to 4 carbon atoms is preferably a propionyl group or a butyryl group. With these films, a solution having a preferable solubility can be prepared, and in particular, in a non-chlorine organic solvent, a good solution can be prepared. Furthermore, a solution having a low viscosity and good filterability can be prepared.

  Glucose units having β-1,4 bonds constituting cellulose have free hydroxyl groups at the 2nd, 3rd and 6th positions. Cellulose acylate is a polymer obtained by acylating part or all of these hydroxyl groups with an acyl group. The degree of acyl substitution means the sum of the ratios of acylation of the hydroxyl groups of cellulose located at the 2-position, 3-position and 6-position (100% acylation at each position is substitution degree 1).

  The acyl group having 2 or more carbon atoms may be an aliphatic group or an allyl group, and is not particularly limited. These are, for example, cellulose alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, aromatic alkylcarbonyl esters, and the like, each of which may further have a substituted group. Preferred examples of these are acetyl group, propionyl group, butanoyl group, heptanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, isobutanoyl group. Group, tert-butanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group and the like. Among these, an acetyl group, a propionyl group, a butanoyl group, a dodecanoyl group, an octadecanoyl group, a tert-butanoyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, a cinnamoyl group, and the like are more preferable, and an acetyl group is particularly preferable. A propionyl group and a butanoyl group (when the acyl group has 2 to 4 carbon atoms), more preferably an acetyl group (when the cellulose acylate is cellulose acetate).

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

  As the catalyst, when the acylating agent is an acid anhydride, a protic catalyst such as sulfuric acid is preferably used. When the acylating agent is an acid chloride (for example, CH3CH2COCl), a basic compound is used. Used.

  The most common industrial synthesis method of cellulose mixed fatty acid ester is to use cellulose corresponding to fatty acid corresponding to acetyl group and other acyl groups (acetic acid, propionic acid, valeric acid, etc.) or their anhydrides. This is a method of acylating with a mixed organic acid component.

In the present invention, it is from the viewpoint of retardation wavelength dispersion that the cellulose acylate film of the low-substituted cellulose acylate film satisfies the following formulas (3) and (4) used in the low-substituted layer. preferable.
Formula (3) 1.0 <X1 <2.7
(In Formula (3), X1 represents the substitution degree of the acetyl group of the cellulose acylate of the low substitution degree layer.)
Formula (4) 0 <= Y1 <1.5
(In Formula (4), Y1 represents the total substitution degree of acyl groups having 3 or more carbon atoms in the cellulose acylate of the low substitution degree layer.)
Note that X1 + Y1 = Z1 is established between X1 and Y1 and Z1 in the formula (1).

The cellulose acylate used in the high substitution layer of the low substitution cellulose acylate film preferably satisfies the following formulas (5) and (6) from the viewpoint of retardation wavelength dispersion.
Formula (5) 1.2 <X2 <3.0
(In Formula (5), X2 represents the substitution degree of the acetyl group of the cellulose acylate of the high substitution degree layer.)
Formula (6) 0 <= Y2 <1.5
(In Formula (6), Y2 represents the total substitution degree of acyl groups having 3 or more carbon atoms in the cellulose acylate of the high substitution degree layer.)
Note that the relationship of X2 + Y2 = Z2 holds between X2 and Y2 and Z2 in the formula (2).

  The cellulose acylate used in the present invention can be synthesized, for example, by the method described in JP-A-10-45804.

If necessary, a non-phosphate ester compound, a plasticizer, a retardation developer, a deterioration inhibitor, an ultraviolet absorber, a peeling accelerator, a matting agent, and the like may be added.
The low-substituted cellulose acylate film is preferably produced by a solution casting method as in the case of the cellulose acylate film, and is subjected to stretching treatment after the solution casting to bring the optical properties into a desired range. preferable.

The polymer film can be produced using various melt film-forming apparatuses according to various melt film-forming methods.
Melt film formation (i) Dry It is preferable to use a pelletized one, and it is preferable to reduce the moisture in the pellet prior to melt film formation.

In the present invention, in order to adjust the water content of the cellulose acylate to a preferable amount, it is preferable to dry the cellulose acylate. The drying method is often dried using a dehumidifying air dryer, but is not particularly limited as long as the desired moisture content can be obtained (heating, blowing, decompression, stirring, etc. alone or in combination) It is preferable that the drying is performed efficiently, and more preferably, the drying hopper is made into a heat insulating structure). The drying temperature is preferably 0 to 200 ° C, more preferably 40 to 180 ° C, and particularly preferably 60 to 150 ° C. When the drying temperature is too low, not only does drying take time, but the moisture content does not fall below the target value, which is not preferable. On the other hand, if the drying temperature is too high, the resin sticks and is not preferable. The amount of drying air used is preferably 20 to 400 m ³ / time, more preferably 50 to 300 m ³ / hour, and particularly preferably 100 to 250 m ³ / hour. If the amount of drying air is small, the drying efficiency is poor, which is not preferable. On the other hand, even if the air volume is increased, if the amount is more than a certain amount, further improvement of the drying effect is small and not economical. The dew point of air is preferably 0 to -60 ° C, more preferably -10 to -50 ° C, and particularly preferably -20 to -40 ° C. The drying time is required to be at least 15 minutes, more preferably 1 hour or more, and particularly preferably 2 hours or more. On the other hand, even if it is dried for more than 50 hours, there is little effect of reducing the moisture content, and there is a concern about thermal degradation of the resin, so it is not preferable to unnecessarily increase the drying time. The cellulose acylate used in the production of the film preferably has a moisture content of 1.0% by mass or less, more preferably 0.1% by mass or less, and 0.01% by mass or less. Particularly preferred.

(Ii) Melt extrusion The above-described cellulose acylate resin is supplied into the cylinder through a supply port of an extruder (separate from the pelletizing extruder). In the cylinder, in order from the supply port side, a supply unit (region A) for quantitatively transporting the cellulose acylate resin supplied from the supply port, a compression unit (region B) for melt-kneading and compressing the cellulose acylate resin, and melt-kneading and compression And a measuring section (area C) for measuring the cellulose acylate resin. The resin is preferably dried in order to reduce the amount of water by the above-mentioned method. However, in order to prevent the molten resin from being oxidized by residual oxygen, the inside of the extruder is in an inert (nitrogen or the like) air flow or with a vent. More preferably, it is carried out while evacuating using an extruder. The screw compression ratio of the extruder is set to 2.5 to 4.5, and L / D is set to 20 to 70. Here, the screw compression ratio is expressed by the volume ratio between the supply unit A and the metering unit C, that is, the volume per unit length of the supply unit A ÷ the volume per unit length of the metering unit C. It is calculated using the outer diameter d1 of the shaft, the outer diameter d2 of the screw shaft of the measuring section C, the groove diameter a1 of the supply section A, and the groove diameter a2 of the measuring section C. L / D is the ratio of the cylinder length to the cylinder inner diameter. Moreover, extrusion temperature is set to 190-240 degreeC. When the temperature in the extruder exceeds 240 ° C., a cooler may be provided between the extruder and the die.

  If the screw compression ratio is less than 2.5 and is too small, it will not be sufficiently melt-kneaded and undissolved parts will be generated, or the shear heat generation will be too small and the crystals will be insufficiently melted, resulting in cellulose acylate resin after production Fine crystals are likely to remain in the film, and bubbles are more likely to be mixed. As a result, the strength of the cellulose acylate resin film is lowered, or when the film is stretched, the remaining crystals inhibit the stretchability and the orientation cannot be sufficiently increased. On the other hand, if the screw compression ratio exceeds 4.5 and is too large, the shear stress is excessively applied and the resin is easily deteriorated due to heat generation, so that the cellulose acylate resin film after production is easily yellowed. On the other hand, when too much shear stress is applied, the molecules are cut and the molecular weight is lowered, so that the mechanical strength of the film is lowered. Therefore, the screw compression ratio is preferably in the range of 2.5 to 4.5, more preferably in order to make the cellulose acylate resin film after production hardly yellowish and the film strength is strong and further hardly breaks. The range of 2.8 to 4.2, particularly preferably 3.0 to 4.0 is preferred.

On the other hand, if the L / D is less than 20 and is too small, melting and kneading are insufficient, and fine crystals are likely to remain in the cellulose acylate resin film after production, as in the case where the compression ratio is small. On the contrary, if L / D exceeds 70 and is too large, the residence time of the cellulose acylate resin in the extruder becomes too long, and the resin tends to be deteriorated. In addition, when the residence time is long, the molecules are cut or the molecular weight is lowered, so that the mechanical strength of the cellulose acylate resin film is lowered. Therefore, L / D is preferably in the range of 20 to 70, more preferably in the range of 22 to 65, in order to make the cellulose acylate resin film after production hardly yellowish and the film strength is strong and further difficult to stretch and break. The range is particularly preferably in the range of 24-50.
The extrusion temperature is preferably in the above temperature range. The cellulose acylate resin film thus obtained has characteristic values having a haze of 2.0% or less and a yellow index (YI value) of 10 or less.

  Here, the haze is an index indicating whether the extrusion temperature is too low, in other words, an index for knowing some of the crystals remaining in the cellulose acylate resin film after production. When the haze exceeds 2.0%, The strength of the cellulose acylate resin film is reduced and breakage during stretching tends to occur. The yellow index (YI value) is an index for knowing whether the extrusion temperature is too high. If the yellow index (YI value) is 10 or less, there is no problem in terms of yellowness.

In general, single-screw extruders with relatively low equipment costs are often used as the types of extruders, and there are screw types such as full flight, madok, and dalmage, but cellulose acid with relatively poor thermal stability. The rate resin is preferably a full flight type.
In addition, although the equipment cost is effective, it is possible to use a twin-screw extruder that can extrude while volatilizing unnecessary volatile components by providing a vent port in the middle by changing the screw segment. There are two types of shaft extruders, the same direction and the different direction, which can be used. However, the type of the same direction rotation with high self-cleaning performance is preferred because a stagnant portion is hardly generated. The twin-screw extruder is effective in equipment, but it is suitable for film formation of cellulose acetate resin because it has high kneadability and high resin supply performance and can be extruded at a low temperature. By appropriately arranging the vent opening, it is possible to use the cellulose acylate pellets and powder in an undried state as they are. Also, film smears produced during film formation can be reused without drying.

  In addition, although the diameter of a preferable screw changes with target extrusion rates per unit time, it is 10 to 300 mm, More preferably, it is 20 to 250 mm, More preferably, it is 30 to 150 mm.

(Iii) Filtration It is preferable to perform a so-called breaker plate type filtration in which a filter medium is provided at the exit of the extruder in order to filter foreign matter in the resin and avoid damage to the gear pump due to foreign matter. In order to filter foreign matter with higher accuracy, it is preferable to provide a filtration device incorporating a so-called leaf type disk filter after passing through the gear pump. Filtration can be performed by providing one filtration section, or multistage filtration performed by providing a plurality of places. The filtration accuracy of the filter medium is preferably higher, but the filtration accuracy is preferably 15 μm to 3 μm, more preferably 10 μm to 3 μm, because of the pressure resistance of the filter medium and the increase in filtration pressure due to clogging of the filter medium. In particular, when using a leaf-type disk filter device that finally filters foreign matter, it is preferable to use a filter medium with high filtration accuracy in terms of quality, and it is adjusted by the number of loaded sheets to ensure the suitability of pressure resistance and filter life. Is possible. The type of filter medium is preferably a steel material because it is used under high temperature and high pressure. Among steel materials, stainless steel, steel, etc. are particularly preferable, and stainless steel is particularly preferable in terms of corrosion. . As the configuration of the filter medium, for example, a sintered filter medium formed by sintering a metal long fiber or metal powder can be used in addition to a knitted wire, and a sintered filter medium is preferable from the viewpoint of filtration accuracy and filter life.

(Iv) Gear pump In order to improve the thickness accuracy, it is important to reduce the fluctuation of the discharge amount. A gear pump is provided between the extruder and the die, and a certain amount of cellulose acylate resin is supplied from the gear pump. That is effective. A gear pump is accommodated in a state where a pair of gears composed of a drive gear and a driven gear are engaged with each other, and the drive gear is driven to engage and rotate the two gears, so that a melted state is generated from the suction port formed in the housing. The resin is sucked into the cavity, and a certain amount of the resin is discharged from the discharge port formed in the housing. Even if there is a slight fluctuation in the resin pressure at the tip of the extruder, the fluctuation is absorbed by using a gear pump, the fluctuation in the resin pressure downstream of the film forming apparatus is very small, and the thickness fluctuation is improved. By using a gear pump, it is possible to keep the fluctuation range of the resin pressure in the die portion within ± 1%.

  In order to improve the quantitative supply performance by the gear pump, a method of controlling the pressure before the gear pump to be constant by changing the number of rotations of the screw can also be used. A high-precision gear pump using three or more gears that eliminates the gear pump gear variation is also effective.

  Other advantages of using a gear pump are that the pressure at the screw tip can be reduced to form a film, reducing energy consumption, preventing rise in resin temperature, improving transport efficiency, shortening the residence time in the extruder, L / D can be expected to be shortened. Also, when using a filter to remove foreign matter, if there is no gear pump, the amount of resin supplied from the screw may fluctuate as the filtration pressure increases. It can be resolved. On the other hand, the disadvantages of gear pumps are that the length of the equipment will be longer depending on the equipment selection method, the resin residence time will be longer, and the shearing stress of the gear pump may cause the molecular chain to break. is required.

  The preferred residence time of the resin from the supply port through the extruder until it exits the die is 2 minutes or more and 60 minutes or less, more preferably 3 minutes or more and 40 minutes or less, and even more preferably 4 minutes or more and 30 minutes. Is less than a minute.

  Cellulose acylate resin because the flow of the polymer for bearing circulation of the gear pump becomes worse, and the sealing by the polymer in the drive part and the bearing part becomes worse, and the fluctuation of the metering and liquid feeding pressure increases. It is necessary to design a gear pump (especially clearance) in accordance with the melt viscosity. In some cases, the staying portion of the gear pump causes deterioration of the cellulose acylate resin, and therefore a structure with as little staying as possible is preferable. The polymer pipes and adapters that connect the extruder and gear pump or gear pump and die also need to be designed with as little stagnation as possible, and to stabilize the extrusion pressure of cellulose acylate resin, which has a high temperature dependence of melt viscosity. It is preferable to make the temperature fluctuation as small as possible. Generally, a band heater having a low equipment cost is often used for heating the polymer tube, but it is more preferable to use an aluminum cast heater with less temperature fluctuation. Furthermore, in order to stabilize the discharge pressure of the extruder as described above, it is preferable to heat and melt the barrel of the extruder with a heater divided into 3 or more and 20 or less.

(V) Die The cellulose acylate resin is melted by the extruder configured as described above, and the molten resin is continuously sent to the die via a filter and a gear pump as necessary. As long as the die is designed so that the molten resin does not stay in the die, any type of commonly used T-die, fishtail die, and hanger coat die may be used. There is no problem in placing a static mixer for improving the uniformity of the resin temperature immediately before the T die. The clearance at the T-die exit portion is generally 1.0 to 5.0 times the film thickness, preferably 1.2 to 3 times, and more preferably 1.3 to 2 times. When the lip clearance is less than 1.0 times the film thickness, it is difficult to obtain a good sheet by film formation. Further, when the lip clearance is larger than 5.0 times the film thickness, it is not preferable because the sheet thickness accuracy is lowered. The die is a very important facility for determining the thickness accuracy of the film, and a die that can control the thickness adjustment severely is preferable. Normally, the thickness can be adjusted at intervals of 40 to 50 mm, but preferably a type capable of adjusting the film thickness at intervals of 35 mm or less, more preferably at intervals of 25 mm or less. In addition, since the cellulose acylate resin is highly dependent on the temperature and shear rate of the melt viscosity, it is important to design the die with as little temperature unevenness as possible and uneven flow velocity in the width direction. An automatic thickness adjustment die that measures the film thickness downstream, calculates the thickness deviation, and feeds back the result to the thickness adjustment of the die is also effective in reducing the thickness fluctuation in long-term continuous production.

  For production of a film, a single-layer film forming apparatus with a low equipment cost is generally used. However, in some cases, a film having two or more types of structures can also be manufactured using a multilayer film forming apparatus in order to provide a functional layer on an outer layer. Is possible. In general, the functional layer is preferably thinly laminated on the surface layer, but the layer ratio is not particularly limited.

(Vi) Casting By the above method, the molten resin extruded from the die onto the sheet is cooled and solidified on a cooling drum to obtain a film. At this time, it is preferable to use a method such as an electrostatic application method, an air knife method, an air chamber method, a vacuum nozzle method, or a touch roll method to increase the adhesion between the cooling drum and the melt-extruded sheet. Such an adhesion improving method may be performed on the entire surface of the melt-extruded sheet or a part thereof. In particular, a method called “edge pinning”, in which only both ends of the film are brought into close contact with each other, is often used.

  A method of using a plurality of cooling drums and gradually cooling them is more preferable. In general, it is relatively common to use three cooling drums, but this is not restrictive. The diameter of the cooling drum is preferably 100 mm or more and 1000 mm or less, and more preferably 150 mm or more and 1000 mm or less. The interval between the plurality of cooling drums is preferably 1 mm or more and 50 mm or less, more preferably 1 mm or more and 30 mm or less.

  The cooling drum is preferably 60 ° C. or higher and 160 ° C. or lower, more preferably 70 ° C. or higher and 150 ° C. or lower, and further preferably 80 ° C. or higher and 140 ° C. or lower. Then, it peels off from a cooling drum, winds up after passing through a take-off roller (nip roll). The winding speed is preferably from 10 m / min to 100 m / min, more preferably from 15 m / min to 80 m / min, still more preferably from 20 m / min to 70 m / min. The film forming width is 0.7 m or more and 5 m or less, more preferably 1 m or more and 4 m or less, and further preferably 1.3 m or more and 3 m or less. The thickness of the unstretched film thus obtained is preferably 30 μm or more and 400 μm or less, more preferably 40 μm or more and 300 μm or less, and still more preferably 50 μm or more and 200 μm or less.

  When the so-called touch roll method is used, the surface of the touch roll may be a resin such as rubber or Teflon (registered trademark) or a metal roll. Further, it is possible to use a roll called a flexible roll because the roll surface is slightly dented by the pressure when touched by reducing the thickness of the metal roll, and the crimping area is widened.

  The touch roll temperature is preferably 60 ° C. or higher and 160 ° C. or lower, more preferably 70 ° C. or higher and 150 ° C. or lower, and still more preferably 80 ° C. or higher and 140 ° C. or lower.

(Vii) Winding The sheet thus obtained is preferably trimmed at both ends and wound. The trimmed portion is re-processed as a raw material for the same type of film or as a raw material for a film of a different type after being pulverized or subjected to processing such as granulation or depolymerization / repolymerization as necessary. May be used. As the trimming cutter, any type of rotary cutter, shear blade, knife, or the like may be used. As for the material, either carbon steel or stainless steel may be used. In general, it is preferable to use a cemented carbide blade or a ceramic blade because the life of the blade is long and generation of chips is suppressed.

  Moreover, it is also preferable from a viewpoint of scratch prevention to attach a lami film to at least one surface before winding. A preferable winding tension is 1 kg / m width or more and 50 kg / m width or less, more preferably 2 kg / m width or more and 40 kg / m width or less, and further preferably 3 kg / m width or more and 20 kg / m width or less. When the winding tension is smaller than 1 kg / m width, it is difficult to wind the film uniformly. On the other hand, when the winding tension exceeds 50 kg / m width, the film becomes tightly wound, not only the appearance of winding is deteriorated, but also the bump portion of the film extends due to the creep phenomenon, and the wave of the film Or residual birefringence due to the elongation of the film occurs. The winding tension is preferably detected by tension control in the middle of the line and is wound while being controlled to have a constant winding tension. If there is a difference in film temperature depending on the location of the film production line, the length of the film may be slightly different due to thermal expansion. It is necessary to prevent tension.

  The winding tension can be wound at a constant tension by controlling the tension control. However, it is more preferable that the winding tension is tapered to an appropriate winding tension according to the wound diameter. Generally, the tension is gradually reduced as the winding diameter increases, but in some cases, it may be preferable to increase the tension as the winding diameter increases.

  In addition, about the said winding method, it is a general thing and is the case where the said heat processing is performed off-line. When the heat treatment of the present invention is performed on-line, it must be controlled as described above.

(Cycloolefin)
The polymer film used as the optically anisotropic layer 1 contains at least one selected from a cycloolefin homopolymer and a copolymer, and preferably contains a main component (50% by mass or more of all components). Can do.

Examples of cycloolefin homopolymers and copolymers that can be used in the production of the optically anisotropic layer 1 include polycyclic monomer ring-opening polymers. Specific examples of the polycyclic monomer include the following compounds, but the present invention is not limited to these specific examples.
Bicyclo [2.2.1] hept-2-ene,
Tricyclo [4.3.0.1 ^2,5 ] -8-decene,
Tricyclo [4.4.0.1 ^2,5 ] -3-undecene,
Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
Pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene,
5-methylbicyclo [2.2.1] hept-2-ene,
5-ethylbicyclo [2.2.1] hept-2-ene,
5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,
5-methyl-5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,
5-cyanobicyclo [2.2.1] hept-2-ene,
8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3
-Dodecene,
8-methyl-8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3
-Dodecene,
8-methyl-8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10
] -3-dodecene,
8-methyl-8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10
] -3-dodecene,
8-methyl-8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ]
-3-dodecene,
5-ethylidenebicyclo [2.2.1] hept-2-ene,
8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-phenylbicyclo [2.2.1] hept-2-ene,
8-phenyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-fluorobicyclo [2.2.1] hept-2-ene,
5-fluoromethylbicyclo [2.2.1] hept-2-ene,
5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-pentafluoroethylbicyclo [2.2.1] hept-2-ene,
5,5-difluorobicyclo [2.2.1] hept-2-ene,
5,6-difluorobicyclo [2.2.1] hept-2-ene,
5,5-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5-methyl-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5,5,6-trifluorobicyclo [2.2.1] hept-2-ene,
5,5,6-tris (fluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6,6-tetrafluorobicyclo [2.2.1] hept-2-ene,
5,5,6,6-tetrakis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5-difluoro-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-difluoro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-fluoro-5-pentafluoroethyl-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-difluoro-5-heptafluoro-iso-propyl-6-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-chloro-5,6,6-trifluorobicyclo [2.2.1] hept-2-ene,
5,6-dichloro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-6-trifluoromethoxybicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-6-heptafluoropropoxybicyclo [2.2.1] hept-2-ene,
8-fluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-difluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-pentafluoroethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3
-Dodecene,
8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3
-Dodecene,
8-methyl-8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3
-Dodecene,
8,8,9-trifluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-tris (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10
] -3-dodecene, 8,8,9,9-tetrafluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9,9-tetrakis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5
. 1 ^7,10 ] -3-dodecene,
8,8-difluoro-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5
. 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-pentafluoropropoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoro-8-pentafluoroethyl-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8-heptafluoroiso-propyl-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-chloro-8,9,9-trifluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] −
3-dodecene,
8,9-dichloro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene. These can be used individually by 1 type or in combination of 2 or more types.

  Although there is no restriction | limiting in particular about these molecular weights, Generally, it is preferable that it is about 5000-500000, and it is more preferable that it is about 10000-100000.

The optically anisotropic layer 1 is preferably a polymer film containing a self-supporting cycloolefin homopolymer and copolymer. Of course, it may be a polymer layer formed by coating on a support such as a polymer film, but is more preferably a self-supporting polymer film.
The method for producing the polymer film used as the optically anisotropic layer 1 is not particularly limited, and polymer films produced by various methods can be used. For example, the polymer film may be a polymer film produced by any method such as a melt casting method and a solution casting method. The film forming conditions are described in detail in Japanese Patent Application Laid-Open No. 2004-198952, and can be manufactured with reference to those descriptions.

The polymer film used as the optically anisotropic layer 1 may contain various additives in addition to the cycloolefin homopolymer or copolymer.
The polymer film may contain fine particles as a matting agent. Fine particles that can be used as a matting agent include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and Mention may be made of calcium phosphate. As the fine particles, those containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable. As the fine particles of silicon dioxide, for example, commercially available products such as “Aerosil” R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 {above, manufactured by Nippon Aerosil Co., Ltd.} can be used. . Zirconium oxide fine particles are commercially available, for example, under the trade names of “Aerosil” R976 and R811 {manufactured by Nippon Aerosil Co., Ltd.}, and any of them can be used as a matting agent.
The amount of the matting agent used is preferably 0.01 to 0.3 parts by mass with respect to 100 parts by mass of the polymer component including the cycloolefin homopolymer and copolymer.

  Also, commercially available cycloolefin polymers include the ARTON series (manufactured by JSR Corporation), the ZEONOR series (manufactured by ZEON Corporation), the ZEONEX series (manufactured by ZEON Corporation), and ESCINA (Sekisui Chemical Co., Ltd.). Can be used. In the case of using a commercially available polymer film, the optical properties may be adjusted so as to satisfy the above formula by performing a stretching treatment. For example, when a ZEONOR series polymer film is used, optical properties required for the optically anisotropic layer 1 are obtained by performing longitudinal stretching (stretching in the film longitudinal direction) and / or lateral stretching (stretching in the film width direction). Can be obtained. The longitudinal draw ratio is preferably about 1 to 150%, more preferably about 1 to 50%. The transverse draw ratio is preferably about 2 to 200%, more preferably about 5 to 100%.

  The polymer film used as the optically anisotropic layer 1 is preferably subjected to a surface treatment in order to improve the adhesion with the optically anisotropic layer 2 or the polarizing film. Specific examples include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment, and ultraviolet irradiation treatment. It is also preferable to provide an undercoat layer.

3. Polarizing plate The first and second optically anisotropic laminates having the optically anisotropic layer 1 and the optically anisotropic layer 2 are produced as optical compensation films and can be incorporated into a liquid crystal display as they are. It is preferable that the optically anisotropic laminate, which can be used for a liquid crystal display device as a polarizing plate by being bonded to a polarizing film, is disposed on the liquid crystal cell side of the polarizing film. Moreover, it is preferable that a protective film such as a cellulose acylate film is bonded to the other surface of the polarizing film.

  Examples of the polarizing film include an iodine-based polarizing film, a dye-based polarizing film using a dichroic dye, and a polyene-based polarizing film, and any of them may be used in the present invention. The iodine polarizing film and the dye polarizing film are generally produced using a polyvinyl alcohol film.

A transparent polymer film is preferably used as the protective film bonded to the other surface of the polarizing film. “Transparent” means that the light transmittance is 80% or more. As the protective film, a cellulose acylate film and a polyolefin film containing polyolefin are preferable. Among the cellulose acylate films, a cellulose triacetate film is preferable. Of the polyolefin films, a polynorbornene film containing a cyclic polyolefin is preferable.
The thickness of the protective film is preferably 20 to 500 μm, and more preferably 50 to 200 μm.

  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.

[Preparation of optical compensation film 1]
(1) Production of optically anisotropic layer 1-A (1) -1 Preparation and fluency of dope Plasticizer AA-2 having no negative intrinsic birefringence (ethanediol / phthalic acid (1/1 molar ratio)) And a polymer solution A having the following composition containing a wavelength dispersion adjusting agent AB-1 and heated at 30 ° C. and having a diameter of 3 m through a cast Giesser Cast on drum. The surface temperature of the support was set to −5 ° C., and the coating width was 200 cm. The space temperature of the entire casting part was set to 15 ° C. Manufacturing conditions other than the above, such as the amount of dope to flow and the slit width of the die, were adjusted as appropriate so as to be optimum values based on preliminary experiment data.

――――――――――――――――――――――――――――――――――――――
Composition of polymer solution A ――――――――――――――――――――――――――――――――――――――
-Cellulose acetate with an average substitution degree of 2.94 100.0 parts by mass-Methylene chloride (first solvent) 475.9 parts by mass-Methanol (second solvent) 113.0 parts by mass-Butanol (third solvent) 5.9 0.13 parts by mass of silica particles having an average particle size of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.)
-Plasticizer having no negative intrinsic birefringence (AA-2) 12.0 parts by mass-Wavelength dispersion adjusting agent (compound AB-1 below) 2.0 parts by mass-Citric acid ester 0.01 parts by mass- ―――――――――――――――――――――――――――――――――――――

(1) -2 First Stretching Step And, the cellulose acylate film (web) that has been cast and rotated 50 cm before the end point of the casting portion is 270% of the residual solvent amount, and the film (web) is removed from the drum. It peeled and conveyed by the pin tenter, and extended | stretched 40% in the film conveyance direction. The residual solvent amount when the web was peeled from the drum was defined as the residual solvent amount at the start of the first stretching step. In addition, the amount of residual solvent at this time was calculated | required from the mass change before and behind making a part of web peeled from the drum sample and drying at 120 degreeC for 2 hours.
In addition, the draw ratio (%) of the film in the first stretching step was determined from the ratio of the drum speed and the tenter transport speed. Further, the temperature of the drum was adjusted by controlling the temperature of the drum with a refrigerant so that the stretching temperature (film surface temperature of the web) was -7 ° C. The stretching speed was 1000% / min.

(1) -3 Drying Step, Second Stretching Step After the first stretching step, a part of the web before drying was sampled, and the residual solvent amount was determined from the mass change before and after drying at 120 ° C. for 2 hours.
Then, it dried so that a drying temperature (film film surface temperature) might be 80 degreeC as a drying (crystallization process) process. The residual volatile content at the start of the drying process was 30%. When the residual solvent amount became 5%, it was conveyed by a pin tenter to perform the second stretching step. The drying temperature was adjusted by controlling the temperature of the stretching zone with drying air.
Thereafter, the amount of residual solvent before the start of the second stretching step was determined from the change in mass before and after being dried at 120 ° C. for 2 hours by sampling a part of the web in the drying zone. Then, it extended | stretched 1% at 135 degreeC in the direction orthogonal to a film conveyance direction using the pin tenter. The stretching temperature (film surface temperature of the film) was adjusted by controlling with the drying air. The stretching speed was 60% / min.
In addition, the draw ratio (%) of the film in a 2nd extending process was calculated | required by the difference of the distance between the pin tenters before a 2nd extending process start, and the distance between the pin tenters after extending | stretching.

(1) -4 Post-drying step, winding Further, the film after the second stretching step was dried at 140 ° C. for 20 minutes.
Thus, a cellulose acylate film having a width of 1400 mm and a film thickness of 150 μm was obtained and wound up by a winder.

  The obtained cellulose acylate film had Re = 75 nm, Rth = 70 nm, and Nz = 1.4, and satisfied the characteristics required for the optically anisotropic layer 1. This film was used as the optically anisotropic layer 1-A.

(2) Formation of optically anisotropic layer 2-A (2) -1 Saponification treatment After passing through a dielectric heating roll at a temperature of 60 ° C. and raising the surface temperature of the film prepared above to 40 ° C., the following After applying the alkaline solution having the composition shown in FIG. 14 at 14 mL / m ² using a bar coater and keeping it under a steam far infrared heater (manufactured by Noritake Co., Ltd.) heated to 110 ° C. for 10 seconds, Using this, 3 mL / m ^{2 of} pure water was applied. 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.

────────────────────────────────────
Composition of alkaline solution for saponification treatment────────────────────────────────────
Potassium hydroxide 4.7 parts by weight of water 15.7 parts by mass Isopropanol 64.8 parts by mass Propylene glycol 14.9 parts by mass Surfactant _{(C 16 H 33 O (CH} 2 CH 2 0) 10 H ) 1.0 part by mass ─────────────────────────────────────

(2) -2 Formation of Alignment Film One side of the cellulose acetate film prepared above was saponified.
An alignment film coating solution having the following composition was applied to the saponified surface and dried to form an alignment film. Thereafter, the alignment film surface was rubbed.
Composition of alignment film coating solution ――――――――――――――――――――――――――
Denatured polyvinyl alcohol 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde 0.5 parts by weight ――――――――――――――――――――――――――

(2) -3 Formation of optically anisotropic layer A coating solution having the following composition was prepared. Composition of coating liquid (S1) containing rod-like liquid crystal compound ――――――――――――――――――――――――――――――――――――
The following rod-like liquid crystalline compound (I) 100 parts by mass 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 The following fluorine system Polymer 0.1 parts by weight Methyl ethyl ketone 172 parts by weight ――――――――――――――――――――――――――――――――――――

  This coating solution is continuously applied to the rubbing-treated surface of the alignment film using a bar coater, dried, and heated (alignment aging), and further irradiated with ultraviolet rays to form an optically anisotropic layer having a thickness of 0.7 μm. Formed. As shown in the table which will be described later, this layer contains rod-like liquid crystals in which Re [+40] and Re [−40] are not equal and are fixed in an inclined alignment state, and the optically anisotropic layer 2 It was found that the layer satisfies the Re required for. This layer is referred to as an optically anisotropic layer 2-A. Thus, the optical compensation film 1 having the optically anisotropic layer 1-A and the optically anisotropic layer 2-A was produced.

[Preparation of optical compensation film 2]
The polymer solution B was prepared by changing the composition of the polymer solution used for the production of the optically anisotropic layer 1-A (cellulose acylate film) of the optical compensation film 1 as follows.
First, 12.0 parts by mass of plasticizer AA-2 was added to 10.0 parts by mass of plasticizer AA-1 (condensate with ethanediol / adipic acid (1/1 molar ratio) (number average molecular weight 1000)). Instead, 1.5 parts by mass of the following retardation adjusting agent BB-1 was added, and the wavelength dispersion adjusting agent AB-1 was removed. In this way, a polymer solution B was prepared.

  Using this polymer solution B, a cellulose acylate film was produced in the same manner, except that the stretching ratio in the first stretching step was changed to 30%. In this manner, a cellulose acylate film was produced. This film had Re = 200 nm, Rth = 150 nm, and a film thickness of 185 μm, and satisfied the characteristics as the optically anisotropic layer 1. This film was used as the optically anisotropic layer 1-B.

(2) Production of optical compensation film 2 On this optical anisotropic layer 1-B, an optical anisotropic layer 2-A is formed in the same manner as the optical compensation film 1, and an optical anisotropic layer 1-2 is formed. And the optical compensation film 2 which has the optically anisotropic layer 2-1 was produced.

[Preparation of optical compensation film 3]
(1) Production of Optically Anisotropic Layer 1-C Synthesis of Cellulose Acetate Propionate (CAP) 150 parts by mass of cellulose (hardwood pulp) and 75 parts by mass of acetic acid are placed in a reaction vessel equipped with a reflux apparatus, and 60 ° Stir vigorously for 2 hours while heating to C. The cellulose subjected to such pretreatment swelled and crushed to form a fluff shape. The reaction vessel was placed in a 2 ° C ice water bath for 30 minutes and cooled. Separately, a mixture of 1545 parts by mass of propionic acid anhydride and 10.5 parts by mass of sulfuric acid was prepared as an acylating agent, cooled to −30 ° C., and once in a reaction vessel containing the above-treated cellulose. Added to. After 30 minutes, the external temperature was gradually increased, and the internal temperature was adjusted to 25 ° C. after 2 hours from the addition of the acylating agent. The reaction vessel was cooled in an ice water bath at 5 ° C., and the internal temperature was adjusted to 10 ° C. 0.5 hours after the addition of the acylating agent, and the internal temperature was 23 ° C. after 2 hours. Was kept at 23 ° C. and further stirred for 3 hours. The reaction vessel was cooled in an ice water bath at 5 ° C, and 120 parts by mass of 25% by mass hydrous acetic acid cooled to 5 ° C was added over 1 hour. The internal temperature was raised to 40 ° C. and stirred for 1.5 hours (aging). Next, a solution in which magnesium acetate tetrahydrate was dissolved in 2-fold mol of sulfuric acid in 50% by mass hydrous acetic acid was added to the reaction vessel, and the mixture was stirred for 30 minutes. Cellulose acetate propionate was precipitated by adding 25 parts by mass of hydrous acetic acid 1000 parts by mass, 33% by mass hydrous acetic acid 500 parts by mass, 50% by mass hydrous acetic acid 1000 parts by mass and water 1000 parts by mass in this order. The obtained cellulose acetate propionate precipitate was washed with warm water. After washing, the mixture is stirred in a 0.005 mass% calcium hydroxide aqueous solution at 20 ° C. for 0.5 hour, further washed with water until the pH of the washing solution becomes 7, and then vacuum dried at 70 ° C. It was.

  According to NMR and GPC measurements, the obtained cellulose acylate was cellulose acetate propionate having an acetyl (Ac) degree of 0.30, a propionyl (Pr) degree of 2.63, and a degree of polymerization of 320.

Melt film formation (i) Pelletization 100 parts by mass of the above CAP, plasticizer (polyethylene glycol (molecular weight 600) 5 parts by mass, glycerin diacetate oleate 4 parts by mass) stabilizer bis (2,6-di-t-butyl-4 -0.1 part by weight of methylphenyl, 0.1 part by weight of tris (2,4-di-t-butylphenyl) phosphite), 0.05 part by weight of silicon dioxide particles (Aerosil R972V), UV absorber (2 -(2'-hydroxy-3 ', 5-di-t-butylphenyl) -benzotriazole 0.05 parts by mass, 2,4-hydroxy-4-methoxy-benzophenone 0.1 parts by mass).
An optical adjusting agent (retardation adjusting agent) having the following structure was added thereto.

  These were dried at 100 ° C. for 3 hours, the water content was reduced to 0.1% by mass or less, melted at 180 ° C. using a twin-screw kneader, and then extruded into warm water at 60 ° C. to form strands. It cut | judged and shape | molded in the cylindrical pellet of diameter 3mm and length 5mm.

(Ii) Melt Film Formation The CAP pellets prepared by the above method were dried at 100 ° C. for 5 hours using dehumidified air having a dew point temperature of −40 ° C. to a water content of 0.01 wt% or less. This was put into an 80 ° C. hopper and melted by a melt extruder adjusted from 180 ° C. (inlet temperature) to 220 ° C. (outlet temperature).

  This was solidified with a casting drum of Tg-10 ° C. At this time, electrostatic application was performed 10 cm at each end using each level of electrostatic application method (10 kV wire was placed 10 cm from the point where the melt was attached to the casting drum). The solidified melt is peeled off from the casting drum, both ends (5% each of the total width) are trimmed immediately before winding, and then both ends are subjected to thicknessing (knurling) of 10 mm width and 50 μm height, and then unstretched film Got.

(iii). Stretching Longitudinal (MD) Stretching 20% of the CAP film (residual solvent is 0.1 wt% or less) obtained by the above melt film formation and solution film formation at 20 g at Tg + 15 ° C using two pairs of nip rolls. It was.
Transverse (TD) Stretching After longitudinal stretching, stretching was performed in the transverse direction at a magnification of 80% at Tg + 10 ° C. using a tenter.

(iv). Heat treatment After that, a heat treatment step was performed at a heat treatment temperature of 130 ° C., a heat treatment conveying tension of 10.8 N / cm ² and a heat treatment time of 50 seconds. The obtained CAP film had Re = 170 nm and Rth = 180 nm, which satisfied the optical characteristics as the optically anisotropic layer 1. This CAP film was used as the optically anisotropic layer 1-C.

(2) Production of optical compensation film 3 On this optical anisotropic layer 1-C, the optical anisotropic layer 1-A is formed in the same manner as the optical compensation film 1, thereby forming the optical anisotropic layer 1 An optical compensation film 3 having —C and an optically anisotropic layer 2-A was produced.

[Preparation of optical compensation film 4]
(1) Production of optically anisotropic layer 1-D In producing a CAP film for optically anisotropic layer 1-3, optically anisotropic layer was used except that longitudinal stretching was not performed and lateral stretching was 50%. A CAP film was produced in the same manner as the 1-A CAP film. This CAP film was used as the optically anisotropic layer 1-D.

(2) Production of Optical Compensation Film 4 On this optically anisotropic layer 1-D, an optically anisotropic layer 2-A was formed in the same manner as the optical compensation film 1, and an optical compensation film 4 was produced.

[Preparation of optical compensation film 5]
(1) Preparation of optically anisotropic layer 1-E The following composition was placed in a mixing tank, and each component was dissolved by stirring, followed by filtration with a filter paper having an average pore size of 34 μm and a sintered metal filter having an average pore size of 10 μm. .
――――――――――――――――――――――――――――――
Cyclic polyolefin solution ――――――――――――――――――――――――――――――
Arton G (manufactured by JSR Corporation) 150 parts by mass Methylene chloride 550 parts by mass Ethanol 50 parts by mass ―――――――――――――――――――――――――――――

Next, the following composition containing the ring-opening polymerization cyclic polyolefin solution prepared by the above method was put into a disperser to prepare a mat agent dispersion.
――――――――――――――――――――――――――――――――――
Matting agent dispersion ――――――――――――――――――――――――――――――――――
Silica particles having an average particle size of 16 nm (aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) 2 parts by mass Methylene chloride 75 parts by mass Ethanol 5 parts by mass Cyclic polyolefin solution 10 parts by mass ――――――――――――――― ―――――――――――――――――――

  100 parts by mass of the cyclic polyolefin solution and 1.1 parts by mass of the matting agent dispersion were mixed to prepare a dope for film formation.

(Production of cyclic polyolefin film)
The above dope was cast using a band casting machine. The film peeled off from the band with a residual solvent amount of about 22% by mass was dried and wound up at 140 ° C. while being rolled. The thickness of the produced cyclic polyolefin film was 100 μm.
Subsequently, the film was stretched in a longitudinal uniaxial stretching machine at a film film surface temperature of 170 ° C. and a stretching ratio of 2%. Thereafter, in a tenter stretching machine, a biaxially stretched cycloolefin polymer film was produced by transversely stretching at a film film surface temperature of 170 ° C. and a stretching ratio of 60% and winding up as a roll film. The thickness of this film was 75 μm, Re = 90 nm, and Rth = 95 nm, and the characteristics as the optically anisotropic layer 1 were satisfied. This film was used as the optically anisotropic layer 1-E.

(2) Production of Optical Compensation Film 5 On this optical anisotropic layer 1-E, an optical anisotropic film 2-A was formed in the same manner as the optical compensation film 1, and an optical compensation film 5 was produced.

[Preparation of optical compensation film 6]
(1) Production of optically anisotropic layer 1-F During the production process of the film produced for the optically anisotropic layer 1-E, the dope amount was changed, and a film was produced in the same manner except that. The obtained film had Re = 200 nm and Rth = 200 nm, and the characteristics as the optically anisotropic layer 1 were satisfied. This film was used as the optically anisotropic layer 1-F.

(2) Production of Optical Compensation Film 6 On the optical anisotropic layer 1-F, the optical anisotropic film 2-A was formed in the same manner as the optical compensation film 1, and the optical compensation film 6 was produced.

[Preparation of optical compensation film 7]
The optically anisotropic layer 1-A (cellulose acylate film) produced in the production of the optical compensation film 1 is the same as the optically anisotropic layer 2-A, except that the type of bar coater used is changed. An anisotropic layer 2-B was formed. The obtained optically anisotropic layer 2-B had a thickness of 0.55 μm. As shown in the table which will be described later, this layer contains rod-like liquid crystals in which Re [+40] and Re [−40] are not equal and are fixed in an inclined alignment state, and the optically anisotropic layer 2 It was found that the layer satisfies the Re required for. Thus, the optical compensation film 7 having the optically anisotropic layer 1-A and the optically anisotropic layer 2-B was produced.

[Preparation of optical compensation film 8]
The optically anisotropic layer 1-A (cellulose acylate film) produced in the production of the optical compensation film 1 is the same as the optically anisotropic layer 2-A, except that the type of bar coater used is changed. An anisotropic layer 2-C was formed. The obtained optically anisotropic layer 2-C had a thickness of 0.35 μm. As shown in the table which will be described later, this layer contains rod-like liquid crystals in which Re [+40] and Re [−40] are not equal and are fixed in an inclined alignment state, and the optically anisotropic layer 2 It was found that the layer satisfies the Re required for. Thus, the optical compensation film 8 having the optically anisotropic layer 1-A and the optically anisotropic layer 2-C was produced.

[Preparation of optical compensation film 9]
(1) Preparation of optically anisotropic layer 1-G From the composition of the polymer solution used for preparation of optically anisotropic layer 1-A of optical compensation film 1, a polymer solution was prepared except for the following components. .
・ Plasticizer without negative intrinsic birefringence (above AA-2) 12.0 parts by mass ・ Wavelength dispersion regulator (above compound AB-1) 2.0 parts by mass ・ Citrate ester 0.01 parts by mass Using the polymer solution, a cellulose acylate film was produced without performing the first stretching step, the drying step, and the second drying step. This film had Re = 5 nm and Rth = 80 nm, and did not satisfy the characteristics required for the optically anisotropic layer 1. This film was used as the optically anisotropic layer 1-G.

(2) Production of optical compensation film 9 On this optical anisotropic layer 1-G, optical compensation film 9 is produced by forming optical anisotropic layer 2-A in the same manner as optical compensation film 1. did.

[Preparation of Optical Compensation Film 10]
The cellulose acylate film produced for the optically anisotropic layer 1-A was used as the optical compensation film 10.

[Preparation of optical compensation film 11]
(1) Preparation of optically anisotropic layer 1-H (Preparation of cellulose acylate)
Cellulose acylate was synthesized by the method described in JP-A Nos. 10-45804 and 08-231761, and the degree of substitution was measured. Specifically, sulfuric acid (7.8 parts by mass with respect to 100 parts by mass of cellulose) was added as a catalyst, carboxylic acid serving as a raw material for the acyl substituent was added, and an acylation reaction was performed at 40 ° C. At this time, the kind and substitution degree of the acyl group were adjusted by adjusting the kind and amount of the carboxylic acid. In addition, aging was performed at 40 ° C. after acylation. Further, the low molecular weight component of the cellulose acylate was removed by washing with acetone.

(Preparation of cellulose acylate solution for low substitution layer)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acylate solution.
Cellulose acetate (substitution degree 2.45) 100.0 parts by mass Terephthalic acid / succinic acid / propylene glycol / ethylene glycol copolymer (copolymerization ratio [mol%] = 27.5 / 22.5 / 25 / 25) 19 parts by mass-Methylene chloride 365.5 parts by mass-Methanol 54.6 parts by mass

(Preparation of cellulose acylate solution for high substitution layer)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acylate solution.
Cellulose acetate (substitution degree 2.79) 100.0 parts by mass Triphenyl phosphate 6.0 parts by mass Diphenyl biphenyl phosphate 5.0 parts by mass Silica fine particles R972 (manufactured by Nippon Aerosil) 0.15 parts by mass Methylene chloride 395.0 parts by mass / methanol 59.0 parts by mass

(Production of cellulose acylate film)
The cellulose acylate solution for the low substitution layer is a core layer having a thickness of 56 μm, and the cellulose acylate solution for the high substitution layer is a skin A layer and a skin B layer having a thickness of 2 μm, respectively. Casted. The obtained web (film) was peeled from the band, dried and wound up.
Subsequently, this film was longitudinally stretched in a longitudinal uniaxial stretching machine at a film film surface temperature of 180 ° C. and a stretching ratio of 40%. Thereafter, in a tenter stretching machine, the film was subjected to transverse stretching at a film film surface temperature of 150 ° C. and a stretching ratio of 5%, and wound up as a roll film to produce a biaxially stretched cellulose acylate film.
The thickness of this film was 75 μm, Re = 180 nm, and Rth = 140 nm, and the characteristics as the optically anisotropic layer 1 were satisfied. This film was used as the optically anisotropic layer 1-H.

(2) Production of Optical Compensation Film 11 On this optically anisotropic layer 1-H, an optically anisotropic layer 2-A was formed in the same manner as the optical compensation film 1, and an optical compensation film 11 was produced.

[Preparation of optical compensation film 12]
(1) Production of optically anisotropic layer 1-I During the production process of the film for optically anisotropic layer 1-H, the film was subjected to longitudinal stretching at a film film surface temperature of 180 ° C. and a draw ratio of 40%. A film was prepared in the same manner except that longitudinal stretching was performed at a film surface temperature of 190 ° C. at a stretching ratio of 60%, and transverse stretching at a stretching ratio of 5% was changed to no or not.
The thickness of this film was 75 μm, Re = 250 nm, and Rth = 150 nm, and the characteristics as the optically anisotropic layer 1 were satisfied. This film was used as the optically anisotropic layer 1-I.

(2) Production of Optical Compensation Film 12 On this optically anisotropic layer 1-I, an optically anisotropic layer 2-A was formed in the same manner as the optical compensation film 1, and an optical compensation film 12 was produced.

[Preparation of polarizing plate]
Polarizers were produced by bonding the optical compensation films 1 to 12 produced as described above to the polarizing film in the arrangement shown in the following table.
The polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film. On the surface of the polarizing film opposite to the surface where the optical compensation films 1 to 12 are attached, a commercially available cellulose acetate film (trade name “Fujitac”, manufactured by Fuji Film Co., Ltd.) is saponified, and then polyvinyl alcohol. Affixed using a system adhesive.

[TN mode liquid crystal display]
The liquid crystal display devices 1 to 13 corresponding to Examples 1 to 10 and Comparative Examples 1 to 3 were prepared by pasting the TN mode liquid crystal cells on top and bottom, respectively.
The TN mode liquid crystal cell used is obtained by removing a pair of polarizing plates from a liquid crystal display device (AL2216W, manufactured by Nippon Acer Co., Ltd.). Instead of the peeled polarizing plate, each of the polarizing plates produced above was attached to the viewer side and the backlight side one by one through an adhesive so that the optical compensation film was on the liquid crystal cell side. In this manner, a TN mode liquid crystal display device was produced.

[Evaluation of viewing angle contrast]
The brightness in the diagonal direction (polar angle 80 degrees) in the vertical and horizontal directions during white display and black display was measured, and the contrast was calculated. The results are shown in the table below.

DESCRIPTION OF SYMBOLS 1 Liquid crystal layer 2, 3 Cell board | substrate 4, 5 Polarizer 6, 6 'Optical anisotropic layer 2
7, 7 ′ Optically anisotropic layer 1
DESCRIPTION OF SYMBOLS 10 Liquid crystal cell 12, 12 'Optically anisotropic laminated body 6a, 6'a Liquid crystal molecule 6b, 6'b Rubbing direction 6c, 6'c Inclination angle 6d, 6'd Inclination axis 6e, 6'e Inclination direction

Claims (6)

First and second polarizing films arranged with their absorption axes orthogonal to each other,
First and second cell substrates disposed between the first and second polarizing films (however, the first cell substrate is disposed closer to the first polarizing film, and the second A cell substrate is disposed closer to the second polarizing film), and
A twisted alignment mode liquid crystal cell having at least a liquid crystal layer disposed therebetween, and between the first polarizing film and the liquid crystal cell, and between the second polarizing film and the liquid crystal cell, respectively. A liquid crystal display device having first and second optically anisotropic laminates having at least two optically anisotropic layers 1 and 2.
The order of the arrangement of the first optically anisotropic layer 1 and the optically anisotropic layer 2 in each of the first and second optically anisotropic laminates is symmetrical about the liquid crystal cell,
The optically anisotropic layer 1 has an in-plane retardation at a wavelength of 550 nm of 50 to 300 nm, and a thickness direction retardation of 50 to 250 nm.
The optically anisotropic layer 2 contains a rod-like liquid crystal fixed in an inclined alignment state, and the in-plane retardation at a wavelength of 550 nm is 0 to 100 nm,
The tilt orientation of the optical anisotropic layer 2 in the first optical anisotropic laminate and the tilt orientation of the liquid crystal in the vicinity of the first cell substrate are antiparallel to each other, and the second optical A twisted alignment mode liquid crystal display device in which the tilt orientation of the optically anisotropic layer 2 in the anisotropic laminate and the tilt orientation of the liquid crystal in the vicinity of the second cell substrate of the liquid crystal layer are antiparallel to each other. The twisted alignment mode liquid crystal display device according to claim 1, wherein the optically anisotropic layer 2 satisfies the following formula (I):
Formula (I) 20 nm ≦ Re [+40] −Re [−40] ≦ 125 nm
In the equation, Re [θ] is an in-plane retardation value measured from a direction inclined by an angle θ (°) from the normal direction. The twisted alignment mode liquid crystal display device according to claim 1 or 2, wherein the optically anisotropic layer 2 and the optically anisotropic layer 1 are arranged in this order from the liquid crystal cell side. The optically anisotropic layer 1 has a casting process in which a polymer solution containing at least one cellulose acylate is cast to form a web, and the web formed in the casting process has a residual solvent amount of 100. A stretching process that stretches 5 to 100% in the conveying direction and a drying process that dries the web at a film surface temperature of 50 to 150 ° C. while the residual residual volatile content of the drying process is The twisted alignment mode liquid crystal display device according to any one of claims 1 to 3, wherein the twisted alignment mode liquid crystal display device is a film produced by a production process of 10 to 150 mass% and a final residual volatile content of 10 to 50 mass%. The twisted alignment mode liquid crystal display device according to any one of claims 1 to 4, wherein the optically anisotropic layer 1 is a film containing at least one cellulose acylate containing a propionyl group or a butyryl group. 4. The twisted alignment mode liquid crystal display device according to claim 1, wherein the optically anisotropic layer 1 is a polymer film containing at least one selected from a cycloolefin-based homopolymer and a copolymer.

Images