JP2006085098A - Alignment layer, optical compensation sheet and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device in which not only display quality but also viewing angle of the liquid crystal display device of IPS mode are drastically improved with a simple means. <P>SOLUTION: A pyridinium compound is added to a polyvinyl alcohol type alignment layer used for an optical compensation sheet of the liquid crystal display device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyvinyl alcohol-based alignment film, an optical compensation sheet using the same, and a liquid crystal display device (in particular, an in-plane switching mode in which display is performed by applying a horizontal electric field to a liquid crystal compound aligned in the horizontal direction. Liquid crystal display device).

  As a liquid crystal display device, a so-called TN mode is widely used in which a liquid crystal layer in which nematic liquid crystal is twisted is sandwiched between two orthogonal polarizing plates and an electric field is applied in a direction perpendicular to the substrate. In this method, since the liquid crystal rises with respect to the substrate during black display, birefringence due to the liquid crystalline compound occurs when viewed from an oblique direction, and light leakage occurs. To solve this problem, a system for optically compensating the liquid crystal cell and preventing this light leakage by using a film in which liquid crystal molecules are hybrid-aligned has been put into practical use. However, even if liquid crystal molecules are used, it is very difficult to completely optically compensate the liquid crystal cell without any problem, resulting in a problem that gradation reversal in the lower direction of the screen cannot be suppressed.

  In order to solve such a problem, a liquid crystal display device using a so-called in-plane switching (IPS) mode in which a lateral electric field is applied to the liquid crystal, or a liquid crystal having a negative dielectric anisotropy is vertically aligned in the panel. A vertical alignment (VA) mode in which alignment is divided by protrusions and slit electrodes has been proposed and put into practical use. In recent years, these panels have been developed not only for monitor applications but also for TV applications, and screen brightness has been greatly improved accordingly. For this reason, slight light leakage in the diagonally oblique incidence direction during black display, which has not been considered as a problem in these operation modes, has become apparent as a cause of deterioration in display quality.

  As one means for improving the color tone and the viewing angle of black display, the arrangement of an optical compensation material having birefringence characteristics between the liquid crystal layer and the polarizing plate is also studied in the IPS mode. For example, a white display or halftone display is viewed directly from an oblique direction by arranging a birefringent medium having optical axes orthogonal to each other between the substrate and the polarizing plate to compensate for increase / decrease in retardation of the liquid crystal layer during tilting. It is disclosed that the coloring in the case can be improved (see Patent Document 1). Further, a method using an optical compensation film made of a styrene polymer having a negative intrinsic birefringence or a discotic liquid crystalline compound (see Patent Documents 2, 3, and 4) or an optical compensation film having a positive birefringence and an optical axis. A method of combining a film in the plane of a film with a film having a positive birefringence and an optical axis in the normal direction of the film (see Patent Document 5), a biaxial optical compensation sheet having a retardation of half wavelength Using a film having a negative retardation as a protective film of a polarizing plate and providing an optical compensation layer having a positive retardation on this surface (see Patent Document 7) Has been.

  A film in which the disc surface of the discotic liquid crystal molecules is aligned and fixed so that the disk surface is substantially perpendicular to the surface direction of the support is disclosed (see Patent Document 4). An alignment film having a special molecular structure is disclosed as a technique for substantially vertical alignment (see Patent Documents 8, 9, and 10).

Japanese Patent Laid-Open No. 9-80424 Japanese Patent Laid-Open No. 10-54982 JP-A-11-202323 Japanese Patent Laid-Open No. 9-292522 JP 11-133408 A JP-A-11-305217 JP-A-10-307291 JP 2000-56310 A JP 2000-104073 A JP 2000-105316 A

  Many of the previously proposed methods are methods that improve the viewing angle by canceling the birefringence anisotropy of the liquid crystal in the liquid crystal cell, so the polarization axis crossing angle when the orthogonal polarizing plate is viewed from an oblique direction. There is a problem that the light leakage based on the deviation from orthogonality cannot be solved sufficiently. Even in a system that can compensate for this light leakage, it is very difficult to completely optically compensate the liquid crystal cell without any problem. Furthermore, in the optical compensation sheet for an IPS mode liquid crystal cell that performs optical compensation with a stretched birefringent polymer film, it is necessary to use a plurality of films. As a result, the thickness of the optical compensation sheet is increased, and the display device is made thinner. It is disadvantageous. In addition, since an adhesive layer is used for laminating stretched films, the adhesive layer contracts due to changes in temperature and humidity, and defects such as peeling and warping between films may occur.

  In order to solve these problems, a technique for aligning the discotic liquid crystal molecules substantially vertically as described later in the present invention is necessary. Problems such as getting out occurred. In addition, it is necessary to modify the polymer in order to impart vertical alignment or to synthesize the polymer using a special monomer. As a result, the alignment film becomes expensive. An inexpensive alignment film has been demanded.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an IPS liquid crystal display device with a simple configuration and not only display quality but also a viewing angle that is remarkably improved.

The object of the present invention has been achieved by the following alignment films (1) and (2), optical compensation sheets (3) to (6) below, and liquid crystal display devices (7) to (13) below.
(1) An alignment film comprising a pyridinium compound represented by the following formula (I):

[Wherein L ¹ is a divalent linking group; R ¹ is a hydrogen atom, amino, or a substituted amino group having 1 to 20 carbon atoms; X is an anion; Y ¹ is 5 to 6-membered] A divalent linking group having a ring as a partial structure; and Z is halogen-substituted phenyl, nitro-substituted phenyl, cyano-substituted phenyl, phenyl substituted with an alkyl group having 1 to 10 carbon atoms, and the number of carbon atoms Phenyl substituted with 2 to 10 alkoxy groups, alkyl groups with 1 to 12 carbon atoms, alkynyl groups with 2 to 20 carbon atoms, alkoxy groups with 1 to 12 carbon atoms, 2 carbon atoms A monovalent group selected from the group consisting of an alkoxycarbonyl group having 13 carbon atoms, an aryloxycarbonyl group having 7 to 26 carbon atoms, and an arylcarbonyloxy group having 7 to 26 carbon atoms.

(2) The alignment film according to (1), which is a polyvinyl alcohol-based alignment film.
(3) An optical compensation sheet in which a liquid crystal composition containing a discotic liquid crystal compound is coated on the alignment film according to (1) or (2).
(4) The optical compensation sheet according to (3), wherein the liquid crystal composition further contains an additive that promotes vertical alignment of the discotic liquid crystal compound.
(5) The additive for promoting vertical alignment of the discotic liquid crystal compound is a copolymer containing a repeating unit having a fluoroaliphatic group and a repeating unit represented by the following formula (II): Optical compensation sheet according to (4):

[Wherein R ¹ , R ² and R ³ are each independently a hydrogen atom or a substituent; L is a single bond, or —O—, —CO—, —NR ⁴ —, —S—, A divalent linking group selected from the group consisting of —SO ₂ —, —P (═O) (OR ⁵ ) —, an alkylene group, an arylene group, and combinations thereof, wherein R ⁴ is a hydrogen atom, an alkyl group, An aryl group or an aralkyl group, R ⁵ is an alkyl group, an aryl group or an aralkyl group; and Q is a carboxyl group (—COOH), a salt thereof, a sulfo group (—SO ₃ H), a salt thereof, a phosphonoxy ( -OP (= O) (OH) ₂ ), or a salt thereof.

(6) The optical compensation sheet according to (4), wherein the additive that promotes vertical alignment of the discotic liquid crystal compound is a compound represented by the following formula (III):
(III)
(R ⁰ ) _m −L ⁰ − (W) _n
[In the formula, m is an integer of 1 or more; when m is 1, R ⁰ is 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 m is 2 or more. In the case of an integer, a plurality of R ⁰ are independently of each other, R ⁰ is 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, but at least one is a terminal L ⁰ is an alkyl group having a CF ₃ group or a CF ₂ H group; L ⁰ is an (m + n) -valent linking group; W is a carboxyl group (—COOH), a salt thereof, a sulfo group (—SO 2 ₃ H), a salt thereof, phosphonoxy (—OP (═O) (OH) ₂ ), or a salt thereof; and n is an integer of 1 or more.

  (7) A liquid crystal layer comprising a first polarizing film, an optical compensation film comprising a first retardation region in contact with the first polarizing film and a second retardation region in contact with the first retardation region, a first substrate, and a nematic liquid crystalline compound A liquid crystal display device having a second substrate and a second polarizing film in this order, wherein the nematic liquid crystalline compound is aligned in parallel with the surfaces of the pair of substrates at the time of black display. The retardation value in the plane is 20 nm or less, the retardation value in the thickness direction of the first retardation region is 20 to 120 nm, and the second retardation region is applied on the alignment film described in (1). A liquid crystal composition comprising the discotic liquid crystal compound according to (5) or (6), wherein the slow axis of the second retardation region is the transmission axis of the first polarizing film and the liquid crystal compound during black display It is characterized by being parallel to the slow axis direction of A liquid crystal display device.

(8) The liquid crystal display device according to (7), wherein an in-plane retardation value of the second retardation region is 50 to 200 nm.
(9) The first retardation region is composed of a plurality of layers, and the layer in contact with the second retardation region among the plurality of layers is an alignment film. (7) or (8) Liquid crystal display device.
(10) Any of (7) to (9), characterized in that it has a pair of protective films so as to sandwich the second polarizing film, and the retardation value in the thickness direction of the protective film on the liquid crystal side is 20 nm or less. A liquid crystal display device according to any one of the above.

(11) The liquid crystal display device according to (10), wherein, of the pair of protective films sandwiching the second polarizing film, the protective film on the liquid crystal layer side is a cellulose acetate film or a norbornene resin film.
(12) The liquid crystal display device according to (10), wherein, of the pair of protective films sandwiching the second polarizing film, the liquid crystal side protective film is made of a cellulose acetate film containing a vertically aligned rod-like liquid crystalline compound. .
(13) The first retardation region is composed of a plurality of layers, and a layer in contact with the first polarizing film among the plurality of layers functions as a protective film for the first polarizing film. The liquid crystal display device according to any one of (12).

In the following description, Re (λ) and Rth (λ) represent in-plane retardation and retardation in the thickness direction at a wavelength λ, respectively. A value in the range of 450 to 750 nm is usually used for the wavelength λ. In this specification, a value of 589 nm is used.
Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA · 21ADH (manufactured by Oji Scientific Instruments). Rth (λ) is a wavelength λnm from a direction inclined by + 40 ° with respect to the normal direction of the film, with Re (λ) and an in-plane slow axis (determined by KOBRA · 21ADH) as an inclination axis (rotation axis). The retardation value measured with the incident light and the in-plane slow axis as the tilt angle (rotation axis), measured with the light of wavelength λ nm incident from a direction inclined by -40 ° with respect to the film normal direction KOBRA · 21ADH is calculated based on the retardation values measured in a total of three directions. Here, 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 given below.
Cellulose acylate: 1.48
Cycloolefin polymer: 1.52
Polycarbonate: 1.59
Polymethyl methacrylate: 1.49
Polystyrene: 1.59
By inputting the assumed average refractive index and the film thickness, KOBRA · 21ADH calculates nx, ny, and nz.

Applying the constitutional requirements of the present invention, a pyridinium derivative having a specific structure is added to the alignment film, and the molecules of the discotic liquid crystal compound are aligned in the presence of the fluoroaliphatic group-containing compound having the specific structure in the liquid crystal composition. By doing so, a substantially vertical alignment can be achieved.
Further, the in-plane retardation value (Re) is 20 nm or less, and the retardation in the thickness direction (Rth) is 20 nm to 120 nm. The substantially perpendicularly aligned Re is 50 nm to 200 nm. A second retardation region composed of a liquid crystalline compound, wherein the slow axis of the second retardation region is parallel to the transmission axis of the first polarizing film and the slow axis direction of the liquid crystalline compound during black display; By disposing the second retardation region so as to be closer to the liquid crystal layer than the first retardation region, two sheets are obtained when viewed from an oblique azimuth direction without changing the frontal characteristics. It is possible to improve the decrease in contrast caused by the shift of the absorption axis of the polarizing plate from 90 degrees, particularly the decrease in contrast from an oblique direction of 45 degrees. Furthermore, the contrast can be further improved by setting the Rth of the protective film of the second polarizing film to 20 nm or less.

  Hereinafter, an embodiment of the liquid crystal display device of the present invention and its constituent members will be described in order. 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. FIG. 1 is a schematic diagram showing an example of a pixel region of the liquid crystal display device of the present invention. FIG. 2 is a schematic view of an embodiment of the liquid crystal display device of the present invention.

  In the present specification, “parallel” and “orthogonal” mean that the angle is within a range of strictly less than ± 10 °. In this range, an error from a strict angle is preferably less than ± 5 °, and more preferably less than ± 2 °. Further, “substantially vertical” means within a range of less than ± 20 ° from a strict vertical angle. In this range, an error from a strict angle is preferably less than ± 15 °, and more preferably less than ± 10 °. Further, the “slow axis” means a direction in which the refractive index is maximized. Further, the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified.

  In this specification, unless otherwise specified, the term “polarizing plate” is cut into a size to be incorporated into a long polarizing plate and a liquid crystal device (in this specification, “cutting” includes “punching” and “cutting out”. It is used in the meaning including both of the polarizing plates. In this specification, “polarizing film” and “polarizing plate” are distinguished from each other, but “polarizing plate” means a laminate having a transparent protective film for protecting the polarizing film on at least one surface of the “polarizing film”. It shall be.

[Liquid Crystal Display]
The liquid crystal display device will be described with reference to FIG.
In general, the liquid crystal cell includes a first substrate 14 and a second substrate 18 and a liquid crystal layer 16 sandwiched therebetween. The product Δn · d of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy Δn is optimal in the range of 0.2 to 0.4 μm for the IPS type having no twisted structure in the transmission mode. In this range, the white display luminance is high and the black display luminance is small, so that a bright and high-contrast display device can be obtained. An alignment film (not shown) is formed on the surfaces of the substrates 14 and 18 that are in contact with the liquid crystal layer 16, and the liquid crystal compound is aligned substantially parallel to the surface of the substrate and applied on the alignment film. The liquid crystal compound alignment directions 5a and 5b in the no-voltage application state or the low application state are controlled by the rubbing directions 4, 15, 19 and the like.
In addition, electrodes 2 and 3 capable of applying a voltage to the liquid crystalline compound are formed on the inner surface of the substrate 14 or 18.

  When active driving is performed using a nematic liquid crystal having positive dielectric anisotropy as a field effect liquid crystal, the alignment direction of the liquid crystalline compound in the state where no voltage is applied or in the state where the voltage is low is 5a and 5b in FIG. At this time, a black display is obtained. When applied between the electrodes 2 and 3, the liquid crystalline compound changes its orientation direction in the 6a and 6b directions according to the voltage. Usually, bright display is performed in this state. However, this drawing shows a very small area corresponding to one pixel.

  In FIG. 2, the transmission axis 9 of the first polarizing film 8 and the transmission axis 22 of the second polarizing film 21 are arranged orthogonally. The optical compensation film 10 is composed of two regions, a first phase difference region 11 and a second phase difference region 12. Further, the slow axis of the second retardation region 12 is parallel to the transmission axis 9 of the first polarizing film 8 and the slow axis direction 17 of the liquid crystal compound at the time of black display, and the second retardation region 12 is the first retardation region 12. It must be arranged closer to the liquid crystal layer than the phase difference region 11. The optical characteristics of each layer will be described later.

  Although FIG. 2 shows a configuration in which the first polarizing film 8 is sandwiched between two protective films 7a and 7b, 7b may not be used. Further, when the protective film 7b referred to here is used, the protective film 7b is one of the layers constituting the first retardation region 11 in the present invention. In FIG. 2, the second polarizing film 21 is also sandwiched between two protective films 20a and 20b. The thickness direction retardation Rth of the protective film 20a on the liquid crystal side is preferably 20 nm or less.

  In addition, in FIG. 2, although the aspect of the display device of the transmission mode provided with the upper side polarizing plate and the lower side polarizing plate was shown, this invention may be the aspect of the reflection mode provided with only one polarizing plate, In such a case, since the optical path in the liquid crystal cell is doubled, the optimum value of Δn · d is about the above half value.

  The liquid crystal display device of the present invention is not limited to the configuration shown in FIGS. 1 and 2, and may include other members. For example, a color filter may be disposed between the liquid crystal layer and the polarizing film. Further, an antireflection treatment or a hard coat may be applied to the surface of the protective film of the polarizing film. Moreover, you may use what gave electroconductivity to the structural member. In the case of use as a transmission type, a cold cathode or a hot cathode fluorescent tube, or a backlight using a light emitting diode, a field emission element, or an electroluminescent element as a light source can be disposed on the back surface. In addition, a reflective polarizing plate, a diffusion plate, a prism sheet, or a light guide plate can be disposed between the liquid crystal layer and the backlight. In addition, the liquid crystal display device of the present invention may be of a reflective type. In such a case, only one polarizing plate may be disposed on the observation side, and reflected on the back surface of the liquid crystal cell or the inner surface of the lower substrate of the liquid crystal cell. Place the membrane. Of course, it is also possible to provide a front light using the light source on the liquid crystal cell observation side.

  The liquid crystal display device of the present invention includes an image direct view type, an image projection type, and a light modulation type. The present invention is particularly effective when applied to an active matrix liquid crystal display device using three-terminal or two-terminal semiconductor elements such as TFT and MIM. Of course, a mode applied to a passive matrix liquid crystal display device called time-division driving is also effective.

  Hereinafter, preferred optical characteristics of various members usable in the liquid crystal display device of the present invention, materials used for the members, manufacturing methods thereof, and the like will be described in detail.

[First retardation region of optical compensation film]
Regarding the optical characteristics of the first retardation region, the in-plane retardation Re is 20 nm or less, more preferably 10 nm or less, and most preferably 5 nm or less. The retardation Rth in the thickness direction is 20 nm to 120 nm, and more preferably 40 nm to 100 nm. When the protective film 7b that protects the first polarizing film 8 has optical anisotropy, the protective film 7b is a layer constituting the first retardation region 11, so that Rth of the protective film and others It is required that the total Rth of the layers is 40 nm to 100 nm.

  The optical compensation sheet having this optical characteristic includes an optical compensation sheet made of a birefringent polymer film, and an optically anisotropic layer in which a low-molecular or high-molecular liquid crystalline compound is coated or transferred on a transparent support. Although there are compensation sheets, any of them can be used in the present invention.

  An optical compensation sheet made of a birefringent polymer film having the above optical characteristics can be easily formed by biaxially stretching a polymer film. In addition, cellulose acetates that exhibit this optical property by simply casting without stretching can be suitably used. As this cellulose acetate, what is described in Unexamined-Japanese-Patent No. 2002-90541 can be used. As a material for the polymer film, a synthetic polymer (eg, polycarbonate, polysulfone, polyethersulfone, polyacrylate, polymethacrylate, norbornene resin, cellulose acetate) is generally used.

  As an optical compensation sheet formed on a transparent support by coating or transfer, a rod-shaped cholesteric liquid crystalline composition containing a chiral structural unit is oriented after its helical axis is oriented substantially perpendicular to the substrate, Examples thereof include those obtained by horizontally aligning a discotic liquid crystalline compound having a negative intrinsic birefringence (the director is perpendicular to the substrate), and those obtained by casting and fixing a polyimide polymer on the substrate.

[Second phase difference region of optical compensation film]
The second retardation region includes a substantially vertically aligned discotic liquid crystal compound, and this slow axis is arranged in parallel to the transmission axis of the first polarizing film and the slow axis direction of the liquid crystal compound during black display. The The Re of the second retardation region is preferably 50 nm to 200 nm, and more preferably 80 nm to 160 nm. This adjustment of Re is performed by controlling the thickness of the discotic liquid crystal layer to be formed by coating. Further, the discotic liquid crystalline compound needs to be aligned substantially perpendicular to the film plane (average inclination angle in the range of 70 to 90 degrees). When the average inclination angle is smaller than this, the light leakage distribution becomes asymmetric. Substantially perpendicular means that the average angle (average inclination angle) between the disk surface and the surface of the optically anisotropic layer is in the range of 70 ° to 90 °. These discotic liquid crystalline compounds may be aligned obliquely or may be changed so that the inclination angle gradually changes (hybrid alignment). Even in the case of oblique orientation or hybrid orientation, the average tilt angle is preferably 70 ° to 90 °, more preferably 75 ° to 90 °, and most preferably 80 ° to 90 °.

  Discotic liquid crystalline compounds are described in various literatures (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by the Chemical Society of Japan, Quarterly Chemical Review, No. 22, Chemistry of liquid crystals, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); J. Zhang et al., J Am. Chem. Soc., Vol. 116, page 2655 (1994)). The polymerization of discotic liquid crystalline compounds is described in JP-A-8-27284.

The discotic liquid crystalline compound preferably has a polymerizable group so that it can be fixed by polymerization. For example, a structure in which a polymerizable group is bonded as a substituent to a discotic core of a discotic liquid crystalline compound can be considered. However, when a polymerizable group is directly connected to the discotic core, the alignment state is maintained in the polymerization reaction. It becomes difficult. Therefore, a structure having a linking group between the discotic core and the polymerizable group is preferable. That is, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following formula.
D (-LP) n
In the formula, D is a discotic core, L is a divalent linking group, P is a polymerizable group, and n is an integer of 4 to 12. Preferred specific examples of the discotic core (D), the divalent linking group (L) and the polymerizable group (P) in the above formula are (D1) to (D15) described in JP-A No. 2001-4837, respectively. ), (L1) to (L25), and (P1) to (P18), and the contents described in the publication can be preferably used.

[Second retardation layer forming method]
It is formed by applying a coating liquid containing a discotic liquid crystalline compound or the following polymerizable initiator, vertical alignment agent and other additives onto an alignment film formed on a support.

[Vertical alignment accelerator]
In order to uniformly and vertically align the discotic liquid crystal compound, it is necessary to vertically control the liquid crystal compound on the alignment film interface side and the air interface side. For this purpose, a compound having a function of vertically aligning the liquid crystal compound by an excluded volume effect, an electrostatic effect, or a surface energy effect is added to the alignment film. As for the orientation control on the air interface side, a liquid crystal is a compound that is unevenly distributed at the air interface during the orientation of the discotic liquid crystal and acts to vertically align the liquid crystalline compound by its excluded volume effect, electrostatic effect, or surface energy effect. Mix in the coating solution. A pyridinium derivative is preferably used as an alignment film additive that vertically aligns the liquid crystalline compound on the alignment film interface side. Examples of the compound that is blended in the liquid crystal coating liquid and vertically aligns the liquid crystalline compound include a fluoroaliphatic group, a carboxyl group (—COOH), and a sulfo group (— A compound containing at least one hydrophilic group selected from the group consisting of SO ₃ H), a phosphonoxy group {—OP (═O) (OH) ₂ } and salts thereof is preferably used. Also, by blending these compounds, the coatability is improved and the occurrence of unevenness and repellency is suppressed. The vertical alignment agent will be described in detail below. First, the alignment film and the alignment film additive will be described.

[Alignment film]
Since the alignment film has a function of defining the alignment direction of the discotic liquid crystalline compound, it is essential for realizing a preferred embodiment of the present invention. However, if the alignment state is fixed after aligning the liquid crystalline compound, the alignment film plays the role, and thus is not necessarily an essential component of the present invention. That is, it is possible to produce the polarizing plate of the present invention by transferring only the optically anisotropic layer on the alignment film in which the alignment state is fixed onto the polarizer.
The alignment film is an organic compound (eg, ω-tricosanoic acid) formed by rubbing treatment of an organic compound (preferably a polymer), oblique deposition of an inorganic compound, formation of a layer having a microgroove, or Langmuir-Blodgett method (LB film). , Dioctadecylmethylammonium chloride, methyl stearylate). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known.
The alignment film is preferably formed by polymer rubbing treatment.

  Examples of the polymer include methacrylate copolymers, styrene copolymers, polyolefins, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylol) described in paragraph No. [0022] of JP-A-8-338913. Acrylamide), polyester, polyimide, vinyl acetate copolymer, carboxymethylcellulose, polycarbonate and the like. Silane coupling agents can be used as the polymer. Water-soluble polymers (eg, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, modified polyvinyl alcohol) are preferred, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are more preferred, and polyvinyl alcohol and modified polyvinyl alcohol are most preferred. .

The saponification degree of polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%. The polymerization degree of polyvinyl alcohol is preferably 100 to 5000.
In the alignment film of the present invention, a side chain having a crosslinkable functional group (eg, double bond) is bonded to the main chain, or a crosslinkable functional group having a function of aligning liquid crystalline molecules is introduced into the side chain. It is preferable to do. As the polymer used for the alignment film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used.
When a side chain having a crosslinkable functional group is bonded to the main chain of the alignment film polymer, or a crosslinkable functional group is introduced into a side chain having a function of aligning liquid crystalline molecules, the alignment film polymer and the optically anisotropic film The polyfunctional monomer contained in the conductive layer can be copolymerized. As a result, not only between the polyfunctional monomer and the polyfunctional monomer, but also between the alignment film polymer and the alignment film polymer and between the polyfunctional monomer and the alignment film polymer is firmly bonded by a covalent bond. Therefore, the strength of the optical compensation sheet can be remarkably improved by introducing the crosslinkable functional group into the alignment film polymer.
The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specific examples include those described in paragraphs [0080] to [0100] in JP-A-2000-155216.

  Apart from the crosslinkable functional group, the alignment film polymer can also be crosslinked using a crosslinking agent. Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole, and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [0024] in JP-A-2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By adjusting in this way, even if the alignment film is used for a long time in a liquid crystal display device or left in a high temperature and high humidity atmosphere for a long time, sufficient durability without reticulation can be obtained.

  The alignment film is basically formed by applying a solution containing the polymer, the crosslinking agent, and the additive, which is an alignment film forming material, on a transparent support, followed by drying by heating (crosslinking) and rubbing treatment. be able to. As described above, the crosslinking reaction may be performed at an arbitrary time after coating on the transparent support. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the coating solution is preferably a mixed solvent of an organic solvent (eg, methanol) having a defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the layer surface of an orientation film and also an optically anisotropic layer reduces remarkably.

  The alignment film is preferably applied by spin coating, dip coating, curtain coating, extrusion coating, rod coating, or roll coating. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heating and drying can be performed at 20 ° C to 110 ° C. In order to form sufficient cross-linking, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is particularly preferable. The drying time can be 1 minute to 36 hours, preferably 1 minute to 30 minutes. The pH is also preferably set to an optimum value for the cross-linking agent to be used, and when glutaraldehyde is used, the pH is 4.5 to 5.5, and pH 5 is particularly preferable.

  The alignment film is preferably provided on the transparent support. The alignment film can be obtained by rubbing the surface after crosslinking the polymer layer as described above.

  For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing several times using a cloth or the like in which fibers having a uniform length and thickness are planted on average.

  Next, the alignment film is caused to function to align the discotic liquid crystalline compound of the optically anisotropic layer provided on the alignment film. Thereafter, as necessary, the alignment film polymer and the polyfunctional monomer contained in the optically anisotropic layer are reacted, or the alignment film polymer is crosslinked using a crosslinking agent. The thickness of the alignment film is preferably in the range of 0.1 to 10 μm.

  The alignment film of the present invention is characterized in that the pyridinium compound represented by the formula (I) is added to the polyvinyl alcohol-based alignment film. By adding the pyridinium derivative, the orientation of the discotic liquid crystal compound is regulated substantially vertically in the vicinity of the alignment film.

In the formula (I), L ¹ is an alkylene group and —O—, —S—, —CO—, —SO ₂ —, —NR ^a — (wherein R ^a is an alkyl group having 1 to 5 carbon atoms. Or a hydrogen atom), a divalent linking group having 1 to 20 carbon atoms, which is a combination of an alkenylene group, an alkynylene group or an arylene group.

In the formula (I), 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, and is a hydrogen atom, an unsubstituted amino group or a substituted amino group having 2 to 12 carbon atoms. Particularly preferred 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 the formula (I), 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 (I), Y ¹ is a divalent linking group having 1 to 30 carbon atoms having a 5- to 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- to 6-membered ring represented by Y as a partial structure may have a substituent.

In formula (I), Z is substituted with a halogen-substituted phenyl, nitro-substituted phenyl, cyano-substituted phenyl, phenyl substituted with an alkyl group having 1 to 10 carbon atoms, or an alkoxy group with 2 to 10 carbon atoms. Phenyl, alkyl group having 1 to 12 carbon atoms, alkynyl group having 2 to 20 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkoxycarbonyl group having 2 to 13 carbon atoms, carbon atom An aryloxycarbonyl group having 7 to 26 carbon atoms, an arylcarbonyloxy group having 7 to 26 carbon atoms, cyano-substituted phenyl, halogen-substituted phenyl, phenyl substituted with an alkyl group having 1 to 10 carbon atoms, 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 The number is preferably arylcarbonyloxy group of 7 to 26.
Z may further have a substituent. 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.

  Pyridinium compounds represented by the following formula (Ia) are preferred.

In the formula (Ia), L ³ represents a single bond, —O—, —O—CO—, —CO—O—, —C≡C—, —CH═CH—, —CH═N—, —N═. CH—, —N═N—, —O—AL—O—, —O—AL—O—CO—, —O—AL—CO—O—, —CO—O—AL—O—, —CO—. O-AL-O-CO-, -CO-O-AL-CO-O-, -O-CO-AL-O-, -O-CO-AL-O-CO- or -O-CO-AL- CO-O-. AL is an alkylene group having 1 to 10 carbon atoms. L ³ represents a single bond, —O—, —O—AL—O—, —O—AL—O—CO—, —O—AL—CO—O—, —CO—O—AL—O—, — CO-O-AL-O-CO-, -CO-O-AL-CO-O-, -O-CO-AL-O-, -O-CO-AL-O-CO- or -O-CO- AL-CO-O- is preferred and -O- is most preferred.

In the formula (Ia), L ⁴ represents a single bond, —O—, —O—CO—, —CO—O—, —C≡C—, —CH═CH—, —CH═N—, —N═. CH- or -N = N-.

In the formula (Ia), R ³ is a hydrogen atom, amino, or an alkyl-substituted amino group having 2 to 20 carbon atoms. When R ³ is a dialkyl-substituted amino group, two alkyl 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 ³ is more preferably a hydrogen atom, amino, or a dialkyl-substituted amino group having 2 to 12 carbon atoms, and most preferably a hydrogen atom, amino, or a dialkyl-substituted amino group having 2 to 8 carbon atoms. When R ³ is amino, the 4-position of the pyridinium ring is preferably amino-substituted.

In formula (Ia), Y ² and Y ³ are each independently a 6-membered ring optionally having a substituent. The 6-membered ring includes an aliphatic ring, an aromatic ring (benzene ring) and a heterocyclic ring. Examples of the 6-membered aliphatic ring include a cyclohexane ring, a cyclohexene ring, and a cyclohexadiene ring. Examples of 6-membered heterocyclic rings include pyran ring, dioxane ring, dithiane ring, thiin ring, pyridine ring, piperidine ring, oxazine ring, morpholine ring, thiazine ring, pyridazine ring, pyrimidine ring, pyrazine ring, piperazine ring and triazine ring. Including. Another 6-membered ring or 5-membered ring may be condensed to the 6-membered ring.
Examples of the substituent include a halogen atom, cyano, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms. The alkyl group and alkoxy group may be substituted with an acyl group having 2 to 12 carbon atoms or an acyloxy group having 2 to 12 carbon atoms. The definition of an acyl group and an acyloxy group will be described later.

In the formula (Ia), X is an anion. X is preferably a monovalent anion. Examples of anions include halide ions (fluorine ions, chlorine ions, bromine ions, iodine ions) and sulfonate ions (eg, methanesulfonate ions, p-toluenesulfonate ions, benzenesulfonate ions).
In Formula (Ia), Z ¹ is a hydrogen atom, cyano, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms, and the alkyl group and the alkoxy group have carbon atoms. It may be substituted with an acyl group having 2 to 12 carbon atoms or an acyloxy group having 2 to 12 carbon atoms.
When m is 2, Z ¹ is preferably cyano, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.
When m is 1, Z ¹ is an alkyl group having 7 to 12 carbon atoms, an alkoxy group having 7 to 12 carbon atoms, an acyl-substituted alkyl group having 7 to 12 carbon atoms, or 7 carbon atoms. It is preferably an acyl-substituted alkoxy group having 1 to 12 carbon atoms, an acyloxy-substituted alkyl group having 7 to 12 carbon atoms, or an acyloxy-substituted alkoxy group having 7 to 12 carbon atoms.

The acyl group is represented by —CO—R, the acyloxy group is represented by —O—CO—R, and R is an aliphatic group (alkyl group, substituted alkyl group, alkenyl group, substituted alkenyl group, alkynyl group, substituted alkynyl group) or aromatic. Group (aryl group, substituted aryl group). R is preferably an aliphatic group, and more preferably an alkyl group or an alkenyl group.
In the formula (Ia), m is 1 or 2, and when m is 2, two L ⁴ and two Y ³ may be different.
In the formula (Ia), p is an integer of 1 to 10. C _p H _2p means a chain alkylene group which may have a branched structure. C _p H _2p is preferably a linear alkylene group.

  Specific examples of the compound represented by formula (I) are shown below.

  A pyridinium derivative is generally obtained by alkylating a pyridine ring (Menstokin reaction).

  The preferred range of the content of the pyridinium derivative in the composition varies depending on its use, but in the composition (a composition excluding the solvent in the case of a coating solution) when used for forming an optically anisotropic layer. 0.005 to 8% by mass is preferable, and 0.01 to 5% by mass is more preferable.

In the alignment film of the present invention, a side chain having a crosslinkable functional group (eg, double bond) is bonded to the main chain, or a crosslinkable functional group having a function of aligning liquid crystalline molecules is introduced into the side chain. It is preferable to do. As the polymer used for the alignment film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used.
When a side chain having a crosslinkable functional group is bonded to the main chain of the alignment film polymer, or a crosslinkable functional group is introduced into a side chain having a function of aligning liquid crystalline molecules, the alignment film polymer and the optically anisotropic film The polyfunctional monomer contained in the conductive layer can be copolymerized. As a result, not only between the polyfunctional monomer and the polyfunctional monomer, but also between the alignment film polymer and the alignment film polymer and between the polyfunctional monomer and the alignment film polymer is firmly bonded by a covalent bond. Therefore, the strength of the optical compensation sheet can be remarkably improved by introducing the crosslinkable functional group into the alignment film polymer.
The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specific examples include those described in paragraphs [0080] to [0100] in JP-A-2000-155216.

  Apart from the crosslinkable functional group, the alignment film polymer can also be crosslinked using a crosslinking agent. Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole, and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [0024] in JP-A-2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By adjusting in this way, even if the alignment film is used for a long time in a liquid crystal display device or left in a high temperature and high humidity atmosphere for a long time, sufficient durability without reticulation can be obtained.

  The alignment film is basically formed by applying a solution containing the polymer, the crosslinking agent, and the additive, which is an alignment film forming material, on a transparent support, followed by drying by heating (crosslinking) and rubbing treatment. be able to. As described above, the crosslinking reaction may be performed at an arbitrary time after coating on the transparent support. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the coating solution is preferably a mixed solvent of an organic solvent (eg, methanol) having a defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the layer surface of an orientation film and also an optically anisotropic layer reduces remarkably.

  The alignment film is preferably applied by spin coating, dip coating, curtain coating, extrusion coating, rod coating, or roll coating. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heating and drying can be performed at 20 ° C to 110 ° C. In order to form sufficient cross-linking, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is particularly preferable. The drying time can be 1 minute to 36 hours, preferably 1 minute to 30 minutes. The pH is also preferably set to an optimum value for the cross-linking agent to be used, and when glutaraldehyde is used, the pH is 4.5 to 5.5, and pH 5 is particularly preferable.

  The alignment film is preferably provided on the transparent support. The alignment film can be obtained by rubbing the surface after crosslinking the polymer layer as described above.

  For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing several times using a cloth or the like in which fibers having a uniform length and thickness are planted on average.

  Next, the alignment film is caused to function to align the discotic liquid crystalline compound of the optically anisotropic layer provided on the alignment film. Thereafter, as necessary, the alignment film polymer and the polyfunctional monomer contained in the optically anisotropic layer are reacted, or the alignment film polymer is crosslinked using a crosslinking agent. The thickness of the alignment film is preferably in the range of 0.1 to 10 μm.

[Air interface side vertical alignment agent]
As the air interface side vertical alignment agent in the present invention, the following fluorine-based polymer or a fluorine-containing compound represented by the formula (III) is preferably used.

  A copolymer in which the fluoropolymer includes a repeating unit derived from a fluoroaliphatic group-containing monomer and a repeating unit represented by the following formula (II).

In the formula, each of R ¹ , R ² and R ³ independently represents a hydrogen atom or a substituent; L is a divalent linking group selected from the following linking group group or 2 selected from the following linking group group Represents a divalent linking group formed by combining two or more,
(Linked group group)
Single bond, —O—, —CO—, —NR ⁴ — (R ⁴ represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group), —S—, —SO ₂ —, —P (═O) (OR ⁵ ) — (R ⁵ represents an alkyl group, an aryl group, or an aralkyl group), an alkylene group, and an arylene group;
Q 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.

A fluorine-containing compound represented by the following formula (III).
(III)
(R ⁰ ) _m −L ⁰ − (W) _n
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 m 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 (m + n) -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 n represents an integer of 1 or more.

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, PTFEs, polyvinylidene fluorides, cellulose derivatives, etc. It is done. 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 necessary, and used for the production of a fluoroaliphatic group-containing polymer.

  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 aspect of the fluoropolymer usable in the present invention is a copolymer having a repeating unit derived from a fluoroaliphatic group-containing monomer and a repeating unit containing a hydrophilic group represented by the following formula (II): It is a coalescence.

In the above formula (II), R ¹ , R ² and R ³ 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, 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 ^c ) — (R ^c 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 ³ 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, particularly 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, Particularly preferred are alkenyl groups having 2 to 8 carbon atoms, such as vinyl group, aryl group, 2-butenyl group and 3-pentenyl group), alkynyl groups (preferably having 2 to 20 carbon atoms, more preferred). Is an alkynyl group having 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as propargyl group and 3-pentynyl group. An aryl group (preferably an aryl group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as a phenyl group, a p-methylphenyl group, and a naphthyl group. Aralkyl groups (preferably 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as benzyl group, phenethyl group, 3- Phenylpropyl group and the like), a substituted or unsubstituted amino group (preferably an amino group having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, Unsubstituted amino group, methylamino group, dimethylamino group, diethylamino group, anilino group, etc.),

  An alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly 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, particularly 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, particularly 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, particularly preferably 2-10 carbon atoms. A silamino group, for example, an acetylamino group, a benzoylamino group, and the like, an alkoxycarbonylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 12 carbon atoms). An alkoxycarbonylamino group, for example, a methoxycarbonylamino group), an aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, and particularly preferably 7 to 12 carbon atoms). Aryloxycarbonylamino group, for example, phenyloxycarbonylamino group and the like, sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 1 carbon atoms). 12 sulfonylamino groups such as methanesulfonyl And sulfamoyl groups (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms, such as sulfamoyl group). 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, and particularly preferably carbon number). 1 to 12 carbamoyl groups, for example, unsubstituted carbamoyl group, methylcarbamoyl group, diethylcarbamoyl group, phenylcarbamoyl group and the like),

  An alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, more preferably an alkylthio group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as a methylthio group and an ethylthio group), an arylthio group ( Preferably it is C6-C20, More preferably, it is C6-C16, Most preferably, it is 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, particularly preferably a sulfonyl group having 1 to 12 carbon atoms, such as a mesyl group and a tosyl group, and a sulfinyl group (preferably having a carbon number of 1 to 20, more A sulfinyl group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms is preferable. Zensulfinyl group and the like), ureido group (preferably a ureido group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, an unsubstituted 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, particularly preferably having 1 to 12 carbon atoms). Yes, for example, diethyl phosphoric acid amide group, phenyl phosphoric acid amide group, etc.), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, Carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably having a carbon number of 1 to 0, more preferably a heterocyclic group of 1 to 12, for example, a heterocyclic group having a heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom, such as an imidazolyl group, a pyridyl group, a quinolyl group, a 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, particularly preferably 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 ³ 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, preferably a hydrogen atom or an alkyl group. R ^c in —PO (OR ^c ) — represents an alkyl group, an aryl group or an aralkyl group, and preferably an alkyl group. When R ^b and R ^c 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 It is particularly preferable that ^b- , an alkylene group or an arylene group is contained. When L contains an alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 6 carbon atoms. Specific examples of particularly preferred alkylene groups include methylene, ethylene, trimethylene, tetrabutylene, hexamethylene groups and the like. When L contains an arylene group, the carbon number of the arylene group is preferably 6 to 24, more preferably 6 to 18, and particularly preferably 6 to 12. Specific examples of particularly preferred arylene groups include phenylene 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 particularly 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. Examples of such a substituent include the same substituents as those described above as the substituents for R ^{1 to} R ³ .
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, trimethyl). Benzylammonium, dimethylphenylammonium, etc.), pyridinium salts, etc.), sulfo groups, salts of sulfo groups (examples of cations forming salts are the same as those described above for carboxyl groups), phosphonoxy groups, salts of phosphonoxy groups (salts) Examples of the cation that forms are the same as those described above 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 two 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-eicosene, hexafluoropropene, vinylidene fluoride, chlorotrifluoroethylene, 3, 3, 3-trifluoropropylene, tetrafluoroethylene, vinyl chloride, vinylidene chloride, etc .;
(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 Methoxypolyethylene 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 polycarboxylic 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 its derivatives 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 .

  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, and 1 to 20% by mass of the total amount of the constituent monomers of the fluoropolymer. More preferably, it is 1 to 10% by mass. Since the above-mentioned mass percentage is likely to vary 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 fluorine-based polymer used in the present invention preferably has a mass average molecular weight of 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, and for example, a polymerization method using a vinyl group such as cationic polymerization, radical polymerization, or anionic polymerization 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 singly 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. These organic solvents can be used alone or in combination of two or more. 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, etc.) , 1,1,1-trichloroethane, 1,1,1-tribromooctane, etc.) and low-activity monomers (α-methylstyrene, α-methylstyrene dimer, etc.) can be used, preferably carbon These are mercaptans of 4-16. The amount of these chain transfer agents 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%, preferably 0.05 mol% to 30 mol%, particularly 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.

  In addition, what has a polymeric group as a substituent in order for the fluorine-type polymer of this invention to fix the orientation state of a discotic liquid crystalline compound is also preferable.

  Specific examples of the fluoroaliphatic group-containing copolymer preferably used in the present invention as the fluorine-based polymer are shown below, but the present invention is 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 fluoropolymer used in the present invention can be produced by a publicly known and commonly used method. For example, it can be produced by adding a general-purpose radical polymerization initiator to an organic solvent containing the above-described monomer having a fluoroaliphatic group, a monomer having a hydrogen bonding group, and the like, and polymerizing the mixture. 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 composition varies depending on the application, but when used for forming the optically anisotropic layer, the composition (a composition excluding the solvent in the case of a coating solution) Among these, 0.005 to 8% by mass is preferable, 0.01 to 5% by mass is more preferable, and 0.05 to 1% by mass is even more preferable. If the addition amount of the fluorine-based polymer is less than 0.005% by mass, the effect is insufficient, and if it exceeds 8% by mass, the coating film cannot be sufficiently dried, or the performance as an optical film (for example, letter Adversely affects the uniformity of the foundation.

Next, the fluorine-containing compound represented by the formula (III) will be described.
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 particularly preferably 4 to 8. The alkyl group having a CF ₃ 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 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 particularly 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 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. 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 (m + n) -valent linking group represented by L ⁰ is an alkylene group, an alkenylene group, an aromatic group, a heterocyclic group, —CO—, —NR— (R has 1 carbon atom) 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 I (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—, —SO. _2- represents a divalent linking group selected from the group consisting of a combination 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 have the same meaning as 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 or 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. As the carboxyl group, the sulfo group, and the phosphonoxy group, It is synonymous with the parent 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 particularly 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 those represented by the above formula ( It is synonymous with the carboxyl group, sulfo group and phosphonoxy group represented by W in III), and the preferred 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 cations represented by M, for example, protonium ions, alkali metal ions (lithium ions, sodium ions, potassium ions, etc.), alkaline earth metal ions (barium ions, calcium ions, etc.), ammonium ions and the like 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), 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, particularly preferably an alkylene group having 1 to 8 carbon atoms, a phenyl group, —CO—, —NR—, —O—, —S—, —SO. _2- represents a linking group having a total carbon number of 0 to 20 consisting of a combination thereof. Ar ₁ preferably represents an aromatic hydrocarbon ring having 6 to 12 carbon atoms, particularly preferably a benzene ring or a naphthalene ring. As a carboxyl group represented by W ₃ (—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 a substituent A carboxyl group, a sulfo group, an alkyl group having a phosphonoxy group, an alkoxy group, or an alkylamino 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 cations represented by M, for example, protonium ions, alkali metal ions (lithium ions, sodium ions, potassium ions, etc.), alkaline earth metal ions (barium ions, calcium ions, etc.), ammonium ions and the like 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, particularly 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, particularly preferably 2 to 8 carbon atoms, And aryl groups (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms). For example, phenyl 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 particularly 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, particularly 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, particularly 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, particularly preferably 1 to 12 carbon atoms, for example, an acetyl group, a benzoyl group, a formyl group, a pivaloyl group. An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 carbon atoms). 12 is an alkoxycarbonyl group, and examples thereof include a methoxycarbonyl group and an ethoxycarbonyl group), an aryloxycarbonyl group (preferably having a carbon number of 7 to 20, more preferably a carbon number of 7 to 16, and particularly preferably a carbon number). An aryloxycarbonyl group having 7 to 10 carbon atoms, such as a phenyloxycarbonyl group, an acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 2 carbon atoms). 10 acyloxy groups such as 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, particularly 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, particularly 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, particularly preferably 7 to 12 carbon atoms, such as a phenyloxycarbonylamino group) Sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferred Or a sulfonylamino group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include a methanesulfonylamino group and a benzenesulfonylamino group, and a sulfamoyl group (preferably having a carbon number of 0 to 20). More preferably, it is a sulfamoyl group having 0 to 16 carbon atoms, particularly 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 particularly preferably 1 to 12 carbon atoms. For example, an unsubstituted carbamoyl group, a methylcarbamoyl group, diethylcarbamoyl group Group, phenylcarbamoyl group, etc.),

  An alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, more preferably an alkylthio group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as a methylthio group and an ethylthio group), an arylthio group ( Preferably it is C6-C20, More preferably, it is C6-C16, Most preferably, it is 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, particularly preferably a sulfonyl group having 1 to 12 carbon atoms, such as a mesyl group and a tosyl group, and a sulfinyl group (preferably having a carbon number of 1 to 20, more A sulfinyl group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms is preferable. Zensulfinyl group and the like), ureido group (preferably a ureido group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, an unsubstituted 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, particularly preferably having 1 to 12 carbon atoms). Yes, for example, diethyl phosphoric acid amide group, phenyl phosphoric acid amide group, etc.), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, Carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably having a carbon number of 1 to 0, more preferably a heterocyclic group of 1 to 12, for example, a heterocyclic group having a heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom, such as an imidazolyl group, a pyridyl group, a quinolyl group, a 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, particularly preferably 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 of the present invention preferably has a polymerizable group as a substituent in order to fix the alignment state of the discotic 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. In the following specific examples, III-1 to 42 are examples of the compound represented by formula (III) -a, and III-43 to 66 are examples of the compound represented by formula (III) -b.

  The preferred range of the content of the fluorine-containing compound in the composition varies depending on the use, but when used for forming the optically anisotropic layer, the composition (a composition excluding the solvent in the case of a coating solution) Among these, 0.005 to 8% by mass is preferable, 0.01 to 5% by mass is more preferable, and 0.05 to 1% by mass is even more preferable.

[Coating solvent]
As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination. The coating liquid can be applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

[Polymerization initiator]
The vertically aligned discotic liquid crystal compound is fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction of the polymerizable group (P) introduced into the liquid crystal compound. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,212,970).

The amount of the photopolymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the solid content of the coating solution. Light irradiation for polymerization of discotic liquid crystalline molecules is preferably performed using ultraviolet rays. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. The thickness of the retardation layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, and most preferably 1 to 5 μm.

[Other composition of optically anisotropic layer]
Along with the liquid crystal compound, a plasticizer, a surfactant, a polymerizable monomer, and the like can be used in combination to improve the uniformity of the coating film, the strength of the film, the orientation of the liquid crystal compound, and the like. These materials are preferably compatible with the liquid crystal compound and do not inhibit the alignment.

  Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer and is preferably copolymerizable with the above-described polymerizable group-containing liquid crystal compound. Examples thereof include those described in paragraph numbers [0018] to [0020] in JP-A No. 2002-296423. The amount of the compound added is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass with respect to the discotic liquid crystalline molecules.

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specifically, for example, compounds described in JP-A-2001-330725, paragraphs [0028] to [0056], and paragraphs [0069] to [0126] in Japanese Patent Application No. 2003-295212. And the compounds described.

The polymer used together with the liquid crystal compound is preferably capable of thickening the coating solution. A cellulose ester can be mentioned as an example of a polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass, and in the range of 0.1 to 8% by mass with respect to the liquid crystal molecules so as not to inhibit the alignment of the liquid crystal compound. It is more preferable.
The discotic nematic liquid crystal phase-solid phase transition temperature of the liquid crystal compound is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.

[Support]
In the present invention, a transparent support may be used. As the transparent support, it is preferable to use a polymer film having a small wavelength dispersion. The transparent support preferably has a small optical anisotropy. That the support is transparent means that the light transmittance is 80% or more. Specifically, the small chromatic dispersion means that the ratio of Re400 / Re700 is preferably less than 1.2. Specifically, the small optical anisotropy means that in-plane retardation (Re) is preferably 20 nm or less, and more preferably 10 nm or less. Examples of the polymer include cellulose ester, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate. Cellulose esters are preferred, acetyl cellulose is more preferred, and triacetyl cellulose is most preferred. The polymer film is preferably formed by a solvent cast method. The thickness of the transparent support is preferably 20 to 500 μm, and more preferably 50 to 200 μm. In order to improve the adhesion between the transparent support and the layer (adhesive layer, vertical alignment film or total retardation) provided on the transparent support, surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet light (UV) ) Treatment, flame treatment). An adhesive layer (undercoat layer) may be provided on the transparent support.

  The second retardation region may be composed only of the discotic liquid crystal layer, or may be composed of the discotic liquid crystal layer and other layers. In the latter case, a laminate with a stretched polystyrene film or a laminate with an optically isotropic film such as a cycloolefin can be suitably used.

[Protective film for second polarizing plate]
The protective film for the second polarizing plate is preferably a protective film having no absorption in the visible light region, a light transmittance of 80% or more, and a small retardation based on birefringence. Specifically, the in-plane Re is preferably 20 nm or less, more preferably 10 nm or less, and most preferably 5 nm or less. Further, the retardation Rth in the thickness direction is preferably 20 nm or less, more preferably 10 nm or less, and most preferably 5 nm or less. Any film having this property can be preferably used, but from the viewpoint of durability of the polarizing film, a cellulose acetate or norbornene film is more preferable. As a method for reducing the Rth of the cellulose acetate film, it is effective to mix a liquid crystalline compound into the film.

[Bar-shaped liquid crystalline compound]
Examples of the rod-like liquid crystal compound formed on the protective film of the second polarizing film include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes. Cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. In addition to the above low-molecular liquid crystalline molecules, high-molecular liquid crystalline molecules can also be used.

  In the case of the rod-like liquid crystalline compound used in the present invention, it is preferable to substantially align it vertically. In the case of a rod-like liquid crystal compound, “substantially perpendicular” means that the angle formed by the film surface and the director of the rod-like liquid crystal compound is within a range of 70 ° to 90 °. The rod-like liquid crystalline compound may be oriented obliquely or may be changed so that the inclination angle gradually changes (hybrid orientation). Even in the case of oblique orientation or hybrid orientation, the average tilt angle is preferably 70 ° to 90 °, more preferably 75 ° to 90 °, and most preferably 80 ° to 90 °.

[Vertical alignment film]
In order to align the rod-like liquid crystalline compound vertically on the alignment film side, it is important to reduce the surface energy of the alignment film. Specifically, the surface energy of the alignment film is lowered by the functional group of the polymer, thereby bringing the rod-like liquid crystal compound into a standing state. As the functional group for reducing the surface energy of the alignment film, a hydrocarbon group having 10 or more fluorine atoms and carbon atoms is effective. In order for a fluorine atom or a hydrocarbon group to be present on the surface of the alignment film, it is preferable to introduce a fluorine atom or a hydrocarbon group into the side chain rather than the main chain of the polymer. The fluoropolymer preferably contains fluorine atoms in a proportion of 0.05 to 80% by mass, more preferably in a proportion of 0.1 to 70% by mass, and in a proportion of 0.5 to 65% by mass. More preferably, it is most preferable to contain in the ratio of 1-60 mass%. The hydrocarbon group is an aliphatic group, an aromatic group, or a combination thereof. The aliphatic group may be cyclic, branched or linear. The aliphatic group is preferably an alkyl group (which may be a cycloalkyl group) or an alkenyl group (which may be a cycloalkenyl group). The hydrocarbon group may have a substituent that does not exhibit strong hydrophilicity, such as a halogen atom. The hydrocarbon group has preferably 10 to 100 carbon atoms, more preferably 10 to 60, and most preferably 10 to 40 carbon atoms. The main chain of the polymer preferably has a polyimide structure or a polyvinyl alcohol structure.

  Polyimide is generally synthesized by a condensation reaction of tetracarboxylic acid and diamine. A polyimide corresponding to a copolymer may be synthesized using two or more kinds of tetracarboxylic acids or two or more kinds of diamines. The fluorine atom or hydrocarbon group may be present in the repeating unit derived from tetracarboxylic acid, may be present in the repeating unit derived from diamine, or may be present in both repeating units. When introducing a hydrocarbon group into polyimide, it is particularly preferable to form a steroid structure in the main chain or side chain of the polyimide. The steroid structure present in the side chain corresponds to a hydrocarbon group having 10 or more carbon atoms, and has a function of vertically aligning the liquid crystalline compound. In this specification, the steroid structure is a cyclopentanohydrophenanthrene ring structure or a ring structure in which a part of the bond of the ring is an aliphatic ring (a range in which an aromatic ring is not formed) is a double bond. means.

  Further, as a means for vertically aligning the rod-like liquid crystalline compound, a method of mixing an organic acid with a polymer of polyvinyl alcohol or polyimide can be suitably used. As the acid to be mixed, carboxylic acid, sulfonic acid and amino acid are preferably used. You may use what shows the acidity among the below-mentioned air interface aligning agent. The mixing amount is preferably 0.1% by mass to 20% by mass and more preferably 0.5% by mass to 10% by mass with respect to the polymer.

[Air interface side vertical alignment agent]
Ordinary rod-like liquid crystalline compounds have the property of being tilted and oriented on the air interface side, so it is necessary to control the orientation of the rod-like liquid crystal compound vertically on the air interface side in order to obtain a uniformly vertically aligned state. It is. As the air interface side vertical alignment agent of the rod-like liquid crystal compound, the same compound as the air interface side vertical alignment agent of the discotic liquid crystal compound can be used, and the preferred range of the amount used is also the same. In addition, the compounds described in JP 2002-20363 A and JP 2002-129162 A can be used as the air interface side vertical alignment agent. Also, paragraph numbers 0072 to 0075 of Japanese Patent Application No. 2002-212100, paragraph numbers 0038 to 0040 and 0048 to 0049 of Japanese Patent Application No. 2002-243600, and paragraph numbers 0037 to 0039 of Japanese Patent Application No. 2002-262239. The matters described in Paragraph Nos. 0071 to 0078 of Japanese Patent Application No. 2003-91752 can also be appropriately applied to the present invention.

[Example 1]
<Preparation of IPS mode liquid crystal cell 1>
The electrodes shown in FIG. 1 were provided on a single glass substrate so that the distance between adjacent electrodes was 20 μm, and a polyimide film was provided as an alignment film thereon, and a rubbing treatment was performed. The rubbing process was performed in the direction shown in FIG. A polyimide film was provided on one surface of a separately prepared glass substrate, and a rubbing treatment was performed to obtain an alignment film. Two glass substrates are laminated and bonded so that the alignment films face each other, the distance between the substrates (gap; d) is 3.9 μm, and the rubbing directions of the two glass substrates are parallel. A nematic liquid crystal composition having a refractive index anisotropy (Δn) of 0.0769 and a dielectric anisotropy (Δε) of 4.5 was enclosed. The value of d · Δn of the liquid crystal layer was 300 nm.

<Preparation of optical compensation film 1>
(Production of first retardation region)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution having the following composition.

────────────────────────────────────────
Cellulose acetate solution ────────────────────────────────────────
Cellulose acetate having an acetylation degree of 60.9% 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Methylene chloride (first solvent) 300 parts by weight Methanol (No. 1) 2 solvents) 54 parts by mass 1-butanol (third solvent) 11 parts by mass ───────────────────────────────── ───────

  In another mixing tank, 16 parts by mass of the following retardation increasing agent, 80 parts by mass of methylene chloride and 20 parts by mass of methanol were added and stirred while heating to prepare a retardation increasing agent solution. A dope was prepared by mixing 7 parts by mass of the retardation increasing agent solution with 487 parts by mass of the cellulose acetate solution and stirring sufficiently.

  The obtained dope was cast using a band casting machine. After the film surface temperature on the band reached 40 ° C., the film was dried with warm air of 60 ° C. for 1 minute, and the film was peeled off from the band. Next, the film was dried with a drying air at 140 ° C. for 10 minutes to produce a cellulose acetate film 1 having a thickness of 80 μm.

  The optical characteristics of this film were determined by measuring the dependence of Re on the light incident angle using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments). Re = 8 nm, Rth = 82 nm there were.

(Production of second retardation region)
After the surface of the cellulose acetate film 1 was saponified, an alignment film coating solution having the following composition was coated on the film with a wire bar coater at 20 ml / m ² . Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 100 ° C. for 120 seconds. Next, the formed film was rubbed in a direction parallel to the slow axis direction of the film.

────────────────────────────────────────
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 Additive (I-12) 0.2 parts by weight ─────────────── ─────────────────────────

  Next, 1.8 g of the following discotic liquid crystalline compound, 0.2 g of ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.), a photopolymerization initiator (IRGA) Cure 907, Ciba Geigy Co.) 0.06g, Sensitizer (Kaya Cure DETX, Nippon Kayaku Co., Ltd.) 0.02g, Air Interface Side Vertical Alignment Agent (P-15) 0.0072g 3.9g methyl ethyl ketone The solution dissolved in was applied with a wire bar of # 3.4. This was affixed to a metal frame and heated in a thermostatic bath at 125 ° C. for 3 minutes to align the discotic liquid crystal compound. Next, UV irradiation was performed for 30 seconds using a 120 W / cm high-pressure mercury lamp at 100 ° C. to crosslink the discotic liquid crystalline compound. Then, it stood to cool to room temperature. Thus, the optical compensation film 1 was manufactured.

Discotic liquid crystalline compounds

  Using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments Co., Ltd.), the Re of the optical compensation film 1 depends on the light incident angle, and the contribution of the cellulose acetate film measured in advance is subtracted. As a result, the optical characteristics of only the discotic liquid crystal retardation layer were calculated. Re was 130 nm, Rth was −65 nm, the average tilt angle of the liquid crystal was 89.8 °, and the discotic liquid crystal was perpendicular to the film surface. It was confirmed that they were oriented. The slow axis direction was parallel to the rubbing direction of the alignment film.

  A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film. Using the polyvinyl alcohol-based adhesive, the produced optical compensation film 1 was attached to one side of the polarizing film so that the cellulose acetate film was on the polarizing film side. The transmission axis of the polarizing film and the slow axis of the optical compensation film were arranged in parallel. A commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) was subjected to saponification treatment and attached to the opposite side of the polarizing film using a polyvinyl alcohol-based adhesive. This is arranged so that the slow axis of the optical compensation film 1 is parallel to the rubbing direction of the liquid crystal cell and the discotic liquid crystal coated surface side is on the liquid crystal cell side. Pasted on. Subsequently, a commercially available polarizing plate (HLC2-5618, manufactured by Sanritz Co., Ltd.) was attached to the other side of the IPS mode liquid crystal cell 1 in a crossed Nicol arrangement to produce a liquid crystal display device.

<Measurement of leakage light of the manufactured liquid crystal display device>
The leakage light of the liquid crystal display device thus manufactured was measured. Leakage light when observed from the left diagonal direction of 70 ° was 0.12%.

[Example 2]
In the production of the second retardation region of Example 1, alignment films using I-6 and I-15 instead of I-12 as the alignment film additive were prepared, respectively. A phase difference region was created to obtain optical compensation films 1-a and 1-b. A liquid crystal display device was manufactured in the same manner as in Example 1, and leakage light was measured when the liquid crystal display device was observed from the left oblique direction of 70 °. The results are shown in Table 1.

Table 1 ─────────────────────────────────────────
Film number 1 1-a 1-b
────────────────────────────────────────
Alignment film additive I-12 I-6 I-15
Re 130nm 132nm 129nm of film
Film Rth -65nm -67nm -65nm
Average tilt angle 89.8 ° 89.5 ° 89.8 °
Light leakage of liquid crystal device 0.12 0.14 0.12
────────────────────────────────────────

  In either case, as in Example 1, an optical compensation film in which the discotic liquid crystal compound was vertically aligned was obtained, and a liquid crystal display device with less light leakage was obtained by mounting the optical compensation film on the optical compensation film IPS liquid crystal display device.

[Example 3]
<Preparation of optical compensation film 2>
Using a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd., Re = 3 nm, Rth = 45 nm) as the first retardation region, the surface is saponified, and this is performed on this film. The same alignment film coating solution as in Example 1 was applied at 20 ml / m ² with a wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 100 ° C. for 120 seconds. Next, the formed film was rubbed in a direction parallel to the slow axis direction of the film.

  Subsequently, on the alignment film produced in Example 1, 1.8 g of the discotic liquid crystalline compound used in Example 1, ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 0.2 g, photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 0.06 g, sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.02 g, air interface side vertical alignment agent (III-52 ) A solution obtained by dissolving 0.0036 g in 3.9 g of methyl ethyl ketone was applied with a # 3 wire bar. This was affixed to a metal frame and heated in a thermostatic bath at 125 ° C. for 3 minutes to align the discotic liquid crystal compound. Next, UV irradiation was performed for 30 seconds using a 120 W / cm high-pressure mercury lamp at 100 ° C. to crosslink the discotic liquid crystal compound. Then, it stood to cool to room temperature. Thus, the optical compensation film 2 was manufactured.

  Using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments Co., Ltd.), the light incident angle dependence of Re of the optical compensation film 2 is measured, and the pre-measured contribution of cellulose acetate film is subtracted. Thus, the optical characteristics of only the discotic liquid crystal retardation layer were calculated. Re was 117 nm, Rth was −55 nm, the average tilt angle of the liquid crystal was 89.6 °, and the discotic liquid crystal was perpendicular to the film surface. It was confirmed that they were oriented. The slow axis direction was parallel to the rubbing direction of the alignment film.

  On one of the IPS mode liquid crystal cells 1 prepared above, the optical compensation sheet 2 produced above is placed so that its slow axis is parallel to the rubbing direction of the liquid crystal cell and the discotic liquid crystal application surface side is on the liquid crystal cell side. Pasted to be. Subsequently, a commercially available polarizing plate (HLC2-5618, manufactured by Sanritz Co., Ltd.) is attached on the optical compensation sheet 2 so that the transmission axis is parallel to the rubbing direction of the liquid crystal cell. The same polarizing plate was attached to the other side in a crossed Nicol arrangement to produce a liquid crystal display device.

(Measurement of leakage light of the manufactured liquid crystal display device)
The leakage light of the liquid crystal display device thus manufactured was measured. The leakage light when observed from the left diagonal direction of 70 ° was 0.13%.

[Example 4]
<Production of Second Polarizing Plate 1>
A commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd., Re = 3 nm, Rth = 45 nm) was subjected to saponification treatment, and a commercially available vertical alignment film (JALS- 204R, manufactured by Nippon Synthetic Rubber Co., Ltd.) was diluted 1: 1 with methyl ethyl ketone, and then 2.4 ml / m ^{2 was} applied with a wire bar coater. Immediately, it was dried with warm air of 120 ° C. for 120 seconds.

(Formation of vertically aligned rod-like liquid crystal compound layer)
On the alignment film, 1.8 g of the following rod-like liquid crystal compound, 0.06 g of photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy), 0.02 g of sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.), A solution prepared by dissolving 0.002 g of the air interface side vertical alignment agent (III-52) in 9.2 g of methyl ethyl ketone was applied with a # 2 wire bar. This was affixed to a metal frame and heated in a constant temperature bath at 100 ° C. for 2 minutes to align the rod-like liquid crystal compound. Next, using a 120 W / cm high-pressure mercury lamp at 100 ° C., UV irradiation was performed for 30 seconds to crosslink the rod-like liquid crystal compound. Then, it stood to cool to room temperature. Thus, the protective film 1 of the second polarizing plate was produced.

  Using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments Co., Ltd.), the light incident angle dependency of Re of the protective film 1 was measured. As a result, Re was 3 nm and Rth was 5 nm.

  Next, iodine is adsorbed to the stretched polyvinyl alcohol film to produce a polarizing film. Using the polyvinyl alcohol-based adhesive, the produced protective film 1 is placed on one side of the polarizing film so that the cellulose acetate film is on the polarizing film side. Pasted on. Subsequently, saponification treatment was performed on a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.), and a second polarizing plate was attached to the opposite side of this polarizing film using a polyvinyl alcohol adhesive. Formed. Further, in the same manner as in Example 1, the optical compensation film 1 was attached to one side of the polarizing film so that the cellulose acetate film was on the polarizing film side, and a commercially available cellulose acetate film was attached to the opposite side of the polarizing film. One polarizing plate is placed on one side of the IPS mode liquid crystal cell 1 produced in Example 1 so that the slow axis of the optical compensation film 1 is parallel to the rubbing direction of the liquid crystal cell, and the discotic liquid crystal application surface side is the liquid crystal cell. Affixed to the side. The transmission axis of this polarizing plate and the rubbing direction of the liquid crystal cell are parallel. Further, a second polarizing plate is attached to the other side of the liquid crystal cell so that the transmission axis is perpendicular to the rubbing direction of the liquid crystal cell and the surface of the protective film 1 is on the liquid crystal cell side. Produced.

(Measurement of leakage light of the manufactured liquid crystal display device)
The leakage light of the liquid crystal display device thus manufactured was measured. Light leakage when observed from the left oblique direction of 70 ° was 0.03%.

[Comparative Example 1]
A commercially available polarizing plate (HLC2-5618, manufactured by Sanritz Co., Ltd.) was attached to both sides of the produced IPS mode liquid crystal cell 1 in a crossed Nicol arrangement to produce a liquid crystal display device. An optical compensation film was not used. In the liquid crystal display device, as in Example 1, the polarizing plate was attached so that the transmission axis of the upper polarizing plate was parallel to the rubbing direction of the liquid crystal cell. The leakage light of the liquid crystal display device thus manufactured was measured. The leakage light when observed from the left diagonal direction of 70 ° was 0.55%.

[Comparative Example 2]
Compared to the IPS mode liquid crystal cell 1 manufactured in Example 1, the optical compensation sheet 2 manufactured in Example 2 is such that its slow axis is perpendicular to the rubbing direction of the liquid crystal cell and the discotic liquid crystal application surface side is liquid crystal Affixed to the cell side. Subsequently, a commercially available polarizing plate (HLC2-5618, manufactured by Sanritz Co., Ltd.) is pasted on the optical compensation sheet 2 so that the transmission axis is parallel to the rubbing direction of the liquid crystal cell. The same polarizing plate was attached to the other side in a crossed Nicol arrangement to produce a liquid crystal display device. The leakage light of the liquid crystal display device thus manufactured was measured. The leakage light when observed from the left oblique direction of 70 ° was 1.52% and was extremely large.

[Comparative Example 3]
A liquid crystal display device was produced in the same manner as in Example 1 except that the air interface side vertical alignment agent (P-15) was removed from the discotic liquid crystal coating liquid composition in Example 1, and leakage light was measured. The light leakage when observed from the left diagonal direction of 70 ° was 1.2% and was extremely large.

[Comparative Example 4]
A liquid crystal display device was prepared and leakage light was measured in the same manner as in Example 1 except that the additive (I-12) was removed from the alignment film composition in Example 1. The leakage light when observed from the left diagonal direction of 70 ° was as large as 0.60%.

[Comparative Example 5]
A liquid crystal display device was prepared and leakage light was measured in the same manner as in Example 3 except that the air interface side vertical alignment agent (III-52) was removed from the discotic liquid crystal coating liquid composition in Example 3. The leakage light when observed from the left oblique direction of 70 ° was as large as 0.51%.

It is the schematic which shows the pixel area example of the liquid crystal display device of this invention. It is the schematic which shows the example of the liquid crystal display device of this invention.

Explanation of symbols

1 liquid crystal element pixel region 2 pixel electrode 3 display electrode 4 rubbing direction
5a, 5b Liquid crystal compound director during black display 6a, 6b Liquid crystal compound director during white display 7a, 7b Protective film for first polarizing film 8 First polarizing film
9 Polarization transmission axis of first polarizing film 10 Optical compensation film 11 First retardation region 12 Second retardation region 13 Slow axis 14 of second retardation region First substrate 15 First substrate rubbing direction 16 Liquid crystal layer 17 Liquid crystal The slow axis direction 18 of the organic compound The second substrate 19 The second substrate rubbing directions 20a and 20b The second polarizing film protective film 21 The second polarizing film 22 The second polarizing film Polarization transmission axis

Claims (13)

An alignment film comprising a pyridinium compound represented by the following formula (I):

[Wherein L ¹ is a divalent linking group; R ¹ is a hydrogen atom, amino, or a substituted amino group having 1 to 20 carbon atoms; X is an anion; Y ¹ is 5 to 6-membered] A divalent linking group having a ring as a partial structure; and Z is halogen-substituted phenyl, nitro-substituted phenyl, cyano-substituted phenyl, phenyl substituted with an alkyl group having 1 to 10 carbon atoms, and the number of carbon atoms Phenyl substituted with 2 to 10 alkoxy groups, alkyl groups with 1 to 12 carbon atoms, alkynyl groups with 2 to 20 carbon atoms, alkoxy groups with 1 to 12 carbon atoms, 2 carbon atoms A monovalent group selected from the group consisting of an alkoxycarbonyl group having 13 carbon atoms, an aryloxycarbonyl group having 7 to 26 carbon atoms, and an arylcarbonyloxy group having 7 to 26 carbon atoms.   The alignment film according to claim 1, which is a polyvinyl alcohol-based alignment film.   An optical compensation sheet, wherein a liquid crystal composition containing a discotic liquid crystal compound is applied on the alignment film according to claim 1.   4. The optical compensation sheet according to claim 3, wherein the liquid crystal composition further comprises an additive that promotes vertical alignment of the discotic liquid crystal compound. 5. The additive for promoting vertical alignment of a discotic liquid crystal compound is a copolymer containing a repeating unit having a fluoroaliphatic group and a repeating unit represented by the following formula (II). Optical compensation sheet described in:

[Wherein R ¹ , R ² and R ³ are each independently a hydrogen atom or a substituent; L is a single bond, or —O—, —CO—, —NR ⁴ —, —S—, A divalent linking group selected from the group consisting of —SO ₂ —, —P (═O) (OR ⁵ ) —, an alkylene group, an arylene group, and combinations thereof, wherein R ⁴ is a hydrogen atom, an alkyl group, An aryl group or an aralkyl group, R ⁵ is an alkyl group, an aryl group or an aralkyl group; and Q is a carboxyl group, a salt thereof, a sulfo group, a salt thereof, a phosphonoxy, or a salt thereof]. The optical compensation sheet according to claim 4, wherein the additive that promotes vertical alignment of the discotic liquid crystal compound is a compound represented by the following formula (III):

[In the formula, m is an integer of 1 or more; when m is 1, R ⁰ is 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 m is 2 or more. In the case of an integer, a plurality of R ⁰ are independently of each other, R ⁰ is 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, but at least one is a terminal Is an alkyl group having a CF ₃ group or an alkyl group having a CF ₂ H group; L ⁰ is an (m + n) -valent linking group; W is a carboxyl group, a salt thereof, a sulfo group, a salt thereof, phosphonoxy, or The salt; and n is an integer greater than or equal to 1].   A first polarizing film; an optical compensation film comprising a first retardation region in contact with the first polarizing film; and a second retardation region in contact with the first retardation region; a first substrate; a liquid crystal layer containing a nematic liquid crystalline compound; A liquid crystal display device having a substrate and a second polarizing film in this order, wherein the nematic liquid crystalline compound is aligned parallel to the surfaces of the pair of substrates at the time of black display, wherein the in-plane of the first retardation region The retardation value in the thickness direction of the first retardation region is 20 to 120 nm, and the second retardation region is applied on the alignment film according to claim 1. Item 7. The liquid crystal composition comprising the discotic liquid crystal compound according to item 5 or 6, wherein the slow axis of the second retardation region is the transmission axis of the first polarizing film and the slow axis direction of the liquid crystal compound during black display. Parallel to Crystal display device.   The liquid crystal display device according to claim 7, wherein an in-plane retardation value of the second retardation region is 50 to 200 nm.   9. The liquid crystal display device according to claim 7, wherein the first retardation region is composed of a plurality of layers, and a layer in contact with the second retardation region among the plurality of layers is an alignment film.   10. The liquid crystal side protective film has a pair of protective films so as to sandwich the second polarizing film, and a retardation value in a thickness direction of the protective film on the liquid crystal side is 20 nm or less. 11. Liquid crystal display device.   11. The liquid crystal display device according to claim 10, wherein, of the pair of protective films sandwiching the second polarizing film, the protective film on the liquid crystal layer side is a cellulose acetate film or a norbornene resin film.   12. The liquid crystal display device according to claim 11, wherein, of the pair of protective films sandwiching the second polarizing film, the protective film on the liquid crystal side is made of a cellulose acetate film containing a vertically aligned rod-like liquid crystalline compound.   The first retardation region is composed of a plurality of layers, and a layer in contact with the first polarizing film among the plurality of layers functions as a protective film for the first polarizing film. A liquid crystal display device according to claim 1.

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