JP2000284286A - Liquid crystal alignment film, liquid crystal device, and method of aligning liquid crystal molecule - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal alignment film having a function to align liquid crystalline molecules (especially discotic liquid crystalline molecules) substantially in the perpendicular direction by incorporating a specified modified polyvinylalcohol into the liquid crystal alignment film. SOLUTION: The liquid crystal alignment film formed on a substrate to align a liquid crystal contains a specified modified polyvinylalcohol. The modified polyvinyl alcohol contains 2 to 80 mol% of recurring units having two, three or four aromatic rings or aromatic heterocycles in the side chains, and is crosslinked. The aromatic rings in the recurring units having two, three or four aromatic rings or aromatic heterocycles in the side chains include a benzene ring, indene ring, naphthalene ring, azulene ring, fluorene ring or the like. The aromatic heterocycles are generally five or six-member unsatd. heteroeycles. The heterocycles preferably have double bonds in the max. number. The aromatic heterocycles include a furan ring, thiophene ring, pyrrole ring, oxazole ring, isooxazole ring or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal alignment film provided on a substrate for aligning liquid crystal. The present invention also relates to a liquid crystal element in which a substrate, a liquid crystal alignment film, and a liquid crystal layer formed of liquid crystal molecules are stacked in this order. Further, the present invention relates to a method for aligning liquid crystalline molecules at an average tilt angle in the range of 50 to 90 degrees.

[0002]

2. Description of the Related Art An STN (Super Twisted Nematic) type liquid crystal display device comprises an STN mode liquid crystal cell, two polarizing plates, and one or two optical plates provided between the STN mode liquid crystal cell and the polarizing plate. It consists of a compensation sheet (phase difference plate). The liquid crystal cell is composed of rod-like liquid crystal molecules, two substrates for enclosing the same, and an electrode layer for applying a voltage to the rod-like liquid crystal molecules. In the STN type liquid crystal cell, an alignment film for aligning the rod-like liquid crystal molecules at 180 to 360 degrees is provided on two substrates. S without optical compensation sheet
In the TN type liquid crystal display device, the display image is colored yellow green or yellow due to the birefringence of the rod-like liquid crystal molecules. Coloring of the displayed image is inconvenient in both monochrome display and color display. The optical compensation sheet is used to eliminate such coloring and obtain a bright and clear image. In some cases, the optical compensation sheet may be provided with a function of expanding the viewing angle of the liquid crystal cell. As the optical compensation sheet, a stretched birefringent film has been conventionally used. Optical compensatory sheets for STN-type liquid crystal display devices using stretched birefringent films are disclosed in JP-A-7-104284 and JP-A-7-104284.
It is described in each publication of No. 13021.

It has been proposed to use an optical compensatory sheet having an optically anisotropic layer containing discotic liquid crystal molecules on a transparent support instead of an optical compensatory sheet comprising a stretched birefringent film. The optically anisotropic layer is formed by aligning discotic liquid crystal molecules and fixing the alignment state. Discotic liquid crystalline molecules generally have a large birefringence. The discotic liquid crystal molecules have various alignment forms. The use of discotic liquid crystal molecules makes it possible to produce an optical compensatory sheet having optical properties that cannot be obtained with a conventional stretched birefringent film. An optical compensatory sheet using discotic liquid crystal molecules is disclosed in JP-A-6-214116, US Pat.
679, 5646703 and German Patent Publication 391
It is described in each specification of No. 1620A1. However, these optical compensation sheets are designed assuming a TN type liquid crystal display device as a main use.

It is conceivable that an optical compensation sheet using discotic liquid crystal molecules is used for an STN type liquid crystal display device. In the STN-type liquid crystal display device, rod-like liquid crystal molecules having a super-twist orientation larger than 90 ° are used in the birefringence mode. The STN-type liquid crystal display device is characterized in that even a simple matrix electrode structure without active elements (thin film transistors and diodes) can clearly display a large image by time-division driving. In order to optically compensate an STN-type liquid crystal cell using discotic liquid crystal molecules, it is necessary to vertically align (preferably, twist) the discotic liquid crystal molecules. Japanese Patent Application Laid-Open No. 9-26572 discloses an optical compensation sheet in which discotic liquid crystal molecules are twisted and aligned. Further, the drawings of the publication show a state in which discotic liquid crystal molecules are vertically aligned.
However, among the alignment films disclosed in the publication, those which are substantially effective as vertical alignment films for discotic liquid crystal molecules are the magnetic field alignment films (SiO ₂ ) described in Example 2 of the publication. The sputtering film is heated while applying a magnetic field).

[0005]

Problems to be Solved by the Invention
In the magnetic field alignment film disclosed in the publication, it is difficult as a manufacturing method to stably align the discotic liquid crystal molecules in a vertical and uniform direction. Research is progressing on vertical alignment films of rod-like liquid crystal molecules used in liquid crystal cells rather than vertical alignment films of discotic liquid crystal molecules. For example, in a liquid crystal cell of a vertical alignment (Vertical Alignment) liquid crystal mode in which rod-like liquid crystal molecules are substantially vertically aligned when no voltage is applied, and substantially horizontally when a voltage is applied,
An alignment film for vertically aligning the rod-like liquid crystal molecules is required. Various vertical alignment films have been proposed for aligning rod-like liquid crystal molecules. The rod-shaped liquid crystal molecules and the discotic liquid crystal molecules have completely different molecular structures and optical properties. Regarding the vertical alignment, discotic liquid crystal molecules are different from rod-shaped liquid crystal molecules in that not only the liquid crystal molecules need to be vertically aligned but also the discotic liquid crystal molecules need to be aligned in a certain direction (the directionality is necessary).
As a result of research conducted by the present inventors, most of alignment films known as vertical alignment films of rod-like liquid crystal molecules did not show a function of aligning discotic liquid crystal molecules in a vertical and uniform direction.

An object of the present invention is to provide a liquid crystal alignment film having a function of substantially vertically aligning liquid crystal molecules (particularly discotic liquid crystal molecules). Another object of the present invention is to provide a liquid crystal device in which liquid crystal molecules are stably aligned in a substantially vertical and uniform direction. Still another object of the present invention is to provide a method for stably aligning liquid crystalline molecules in a vertical and uniform direction.

[0007]

The object of the present invention is attained by the following liquid crystal alignment films (1) to (4), the liquid crystal element (5) and the method (6) for aligning liquid crystal molecules. Was done. (1) A liquid crystal alignment film provided on a substrate for aligning liquid crystal, wherein the liquid crystal alignment film contains a modified polyvinyl alcohol, and the modified polyvinyl alcohol has an aromatic ring or an aromatic heterocyclic ring in a side chain. A liquid crystal alignment film comprising 2 to 80 mol% of repeating units having 3, 4 or 4 units, and crosslinked with modified polyvinyl alcohol. (2) The liquid crystal alignment film according to (1), wherein a repeating unit having two, three or four aromatic rings or aromatic heterocycles in a side chain is represented by the following formula (I).

[0008]

Embedded image

In the formula, L ¹ is a single bond, -CO-, -CO
-NH-, -alkylene group-, -CO-NH-alkylene group-, -CO-NH-alkylene group -O-, -CO-
NH-alkylene groups -CO-O- and -CO-NH-
L ² , L ³ and L ⁴ are each independently a single bond, -O-, -CO-, -O-CO-,- CO
-O -, - O-CO- O -, - CO-NH -, - alkylene group -, - O-alkylene group - and - a linking group selected from the group consisting of -O- alkylene group; Ar ^1,
Ar ² , Ar ³ and Ar ⁴ are each independently an aromatic ring or an aromatic heterocyclic ring; and m and n
Is 0 or 1. (3) The liquid crystal alignment film according to (1), wherein the modified polyvinyl alcohol is crosslinked by a reaction between a hydroxyl group of the modified polyvinyl alcohol and a crosslinking agent. (4) The liquid crystal alignment film according to (3), wherein the crosslinking agent is a bifunctional aldehyde.

(5) A liquid crystal element in which a substrate, a liquid crystal alignment film and a liquid crystal layer formed of liquid crystal molecules are laminated in this order, wherein the liquid crystal alignment film contains modified polyvinyl alcohol, and the modified polyvinyl alcohol is It contains 2 to 80 mol% of repeating units having 2, 3, or 4 aromatic rings or aromatic heterocycles in the chain, the modified polyvinyl alcohol is crosslinked, and the liquid crystal molecules have a degree of 50 to 90 degrees. Wherein the liquid crystal element is oriented at an average tilt angle in the range of (6) A liquid crystal alignment film containing 2 to 80 mol% of a repeating unit having two, three or four aromatic rings or aromatic heterocycles in a side chain and containing a crosslinked modified polyvinyl alcohol is used. And aligning the liquid crystalline molecules at an average tilt angle in the range of 50 to 90 degrees.

[0011]

As a result of research, the present inventors have found that a modified polyvinyl alcohol containing 2 to 80 mol% of a repeating unit having two, three or four aromatic rings or aromatic heterocyclic rings in the side chain is aligned in a liquid crystal state. Using the film, we succeeded in aligning liquid crystalline molecules substantially vertically. The liquid crystal alignment film containing the above-mentioned modified polyvinyl alcohol has a better function as a vertical alignment film than a conventional alignment film, and can stably align liquid crystal molecules in a substantially vertical and uniform direction. In a conventional vertical alignment film, liquid crystal molecules are vertically aligned by injecting liquid crystal molecules between two substrates having a vertical alignment film. However, when the number of substrates having a vertical alignment film was one, the tilt angle of liquid crystal molecules near the interface (air interface) opposite to the substrate was small, and the vertical alignment of liquid crystal molecules was insufficient. When the liquid crystal alignment film of the present invention is used, vertical alignment of liquid crystal molecules can be achieved even with one substrate. In addition, when two substrates are used, a better vertical alignment can be achieved than in the past. Further, in the present invention, the modified polyvinyl alcohol is used after being crosslinked. Thereby, the strength of the alignment film containing the modified polyvinyl alcohol is remarkably improved. Therefore, the liquid crystal element using the liquid crystal alignment film of the present invention is also characterized by having excellent durability.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION [Modified polyvinyl alcohol and liquid crystal alignment film] The present invention provides (1) two to three or four repeating units having an aromatic ring or an aromatic heterocyclic ring in a side chain. A modified polyvinyl alcohol containing 80 mol% is used for the liquid crystal alignment film.

(1) A repeating unit having two, three or four aromatic rings or aromatic heterocycles in the side chain Examples of the aromatic ring include a benzene ring, an indene ring, a naphthalene ring,
An azulene ring, a fluorene ring, a phenanthrene ring, an anthracene ring, an acenaphthylene ring, a biphenylene ring, a naphthacene ring, a triphenylene ring and a pyrene ring are included.
The aromatic heterocycle is generally a 5- or 6-membered unsaturated heterocycle. The heterocycle preferably contains the most double bonds. Examples of the aromatic heterocycle include a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, an imidazole ring, a pyrazole ring, a furazane ring, a pyran ring, a pyridine ring, and a pyridazine ring. , A pyrimidine ring and a pyrazine ring. An aromatic ring is more preferable than an aromatic heterocyclic ring, and a benzene ring is particularly preferable. The aromatic ring and the aromatic heterocyclic ring may have a substituent. Examples of the substituent include a halogen atom (F, Cl, Br), carboxyl,
Includes cyano, alkyl, cycloalkyl and alkoxy groups. The alkyl group may have a branch. The number of carbon atoms in the alkyl group is preferably 1 to 20, more preferably 1 to 15, still more preferably 1 to 10, and 1 to 6
Is most preferred. The cycloalkyl group is
Preferably, it is cyclohexyl. The alkoxy group may have a branch. The alkoxy group preferably has 1 to 20 carbon atoms, and has 1 to 15 carbon atoms.
Is more preferable, 1 to 10 is more preferable, and 1 to 6 is most preferable.

The number of aromatic rings or aromatic heterocycles contained in the side chain is 2 to 4, preferably 2 or 3, and most preferably 2. It is preferable that the main chain and the aromatic ring or aromatic heterocyclic ring closest to the main chain be connected via a connecting group without being directly connected. Examples of the linking group include -O-, -O-CO-, -O-CO-NH
-, -O-CO-NH-alkylene group-, -O-CO-
NH-alkylene group -O-, -O-CO-NH-alkylene group -CO-O- and -O-CO-NH-alkylene group -CO-NH- (the left side is bonded to the main chain,
The right side is bonded to the aromatic ring or aromatic heterocyclic ring closest to the main chain). The alkylene group may have a branched or cyclic structure. The number of carbon atoms of the alkylene group is preferably 1 to 30, more preferably 1 to 20, still more preferably 1 to 15, and most preferably 1 to 12. It is preferable that at least two aromatic rings or aromatic heterocycles are directly connected by a single bond. It is particularly preferred that at least two benzene rings are directly connected by a single bond.

The repeating unit having two, three or four aromatic rings or aromatic heterocycles in the side chain is preferably represented by the following formula (I).

[0016]

Embedded image

In the formula (I), L ¹ is a single bond, -C
O-, -CO-NH-, -alkylene group-, -CO-N
H-alkylene group-, -CO-NH-alkylene group-O
-, -CO-NH-alkylene group -CO-O- and-
It is a linking group selected from the group consisting of a CO-NH-alkylene group -CO-NH-. -CO-, -CO-NH- and -alkylene group- are preferable, and -CO-NH- is particularly preferable. The alkylene group may have a branched or cyclic structure. The number of carbon atoms in the alkylene group is 1
It is preferably from 30 to 30, more preferably from 1 to 20, still more preferably from 1 to 15, and most preferably from 1 to 12. In the formula (I), L ² , L ³ and L ⁴ each independently represent a single bond, —O—, —CO—, —O—CO—, —CO—O
-, -O-CO-O-, -CO-NH-, -alkylene group-, -O-alkylene group- and -alkylene group -O
And a linking group selected from the group consisting of: It is particularly preferable that at least one of L ² , L ³ and L ⁴ is a single bond.

In the formula (I), Ar ¹ , Ar ² , Ar
³ and Ar ⁴ are each independently an aromatic ring or an aromatic heterocyclic ring. It is preferably an aromatic ring,
More preferably, it is a benzene ring. Ar ¹ , Ar
It is particularly preferred that ² and Ar ³ are p-phenylene. The aromatic ring and the aromatic heterocyclic ring may have a substituent. Examples of the substituent are as described above.
In the formula (I), m and n are 0 or 1.
m is preferably 0 or 1, and n is preferably 0 (the number of aromatic rings or aromatic heterocycles is 2 or 3), and m and n are each 0 (an aromatic ring or an aromatic heterocycle). Most preferably, the number is 2). Hereinafter, examples of the repeating unit having two, three, or four aromatic rings or aromatic heterocyclic rings in the side chain are shown.

[0019]

Embedded image

[0020]

Embedded image

[0021]

Embedded image

[0022]

Embedded image

[0023]

Embedded image

[0024]

Embedded image

[0025]

Embedded image

[0026]

Embedded image

[0027]

Embedded image

[0028]

Embedded image

[0029]

Embedded image

[0030]

Embedded image

[0031]

Embedded image

[0032]

Embedded image

[0033]

Embedded image

[0034]

Embedded image

[0035]

Embedded image

[0036]

Embedded image

[0037]

Embedded image

[0038]

Embedded image

[0039]

Embedded image

[0040]

Embedded image

[0041]

Embedded image

[0042]

Embedded image

[0043]

Embedded image

[0044]

Embedded image

[0045]

Embedded image

[0046]

Embedded image

[0047]

Embedded image

[0048]

Embedded image

[0049]

Embedded image

[0050]

Embedded image

[0051]

Embedded image

[0052]

Embedded image

[0053]

Embedded image

[0054]

Embedded image

[0055]

Embedded image

[0056]

Embedded image

[0057]

Embedded image

[0058]

Embedded image

[0059]

Embedded image

[0060]

Embedded image

[0061]

Embedded image

[0062]

Embedded image

[0063]

Embedded image

[0064]

Embedded image

[0065]

Embedded image

[0066]

Embedded image

[0067]

Embedded image

[0068]

Embedded image

[0069]

Embedded image

[0070]

Embedded image

[0071]

Embedded image

The modified polyvinyl alcohol preferably contains 2 to 80 mol% of a repeating unit having two, three or four aromatic rings or aromatic heterocycles in the side chain, preferably 3 to 50 mol%. % Is more preferable. Preferred modified polyvinyl alcohol is represented by the following formula (PV). (PV)-(VAl) x- (I) a- (VAc) y- wherein VAl is a repeating unit derived from vinyl alcohol; I is an aromatic ring or an aromatic heterocyclic group in the side chain. VAc is a repeating unit having two, three or four rings; VAc is a repeating unit derived from vinyl acetate; x is 20 to 95 mol% (preferably 30 to 98 mol%); a is 2 to 80 mol% (preferably 3 to 5 mol%); and y is 0 to 3 mol%.
0 mol% (preferably 2 to 20 mol%). A group different from the repeating unit may be bonded to the terminal of the modified polyvinyl alcohol. Examples of the terminal group include an alkylthio group. Hereinafter, examples of the modified polyvinyl alcohol having two, three, or four aromatic rings or aromatic heterocycles will be described. The ratio of the repeating unit is mol%.

[0073] _{PV1 :-( VAl) 80 - (I} -1) 8 -
_{(VAc) 12 - PV2 :-( VAl} ) 53 - (I-1) 35 - (VAc) 12
-PV3:-(VAl) _70- (I-1) _10- (VAc) ₂₀
−PV4: − (VAl) ₇₄ − (I-2) ₂₀ − (VAc) <sub>6
- PV5 :-( VAl) 65 - (</sub> I-2) 27 - (VAc) 12
-PV6:-(VAl) _70- (I-2) _10- (VAc) ₂₀
−PV7: − (VAl) ₇₈ − (I-3) ₁₀ − (VAc) _{12
-S-n-C 12 H 25} PV8 :-( VAl) 85 - (I-3) 13 - (VAc) 2
_{-S-n-C 12 H 25} PV9 :-( VAl) 67 - (I-3) 21 - (VAc) 12
-S-n-C ₁₂ H ₂₅

[0074] _{PV10 :-( VAl) 50 - (I} -4) 38 -
_{(VAc) 12 - PV11 :-( VAl} ) 53 - (I-4) 45 - (VAc) 2
_{- PV12 :-( VAl) 31 - (} I-4) 61 - (VAc) 8
_{- PV13 :-( VAl) 80 - (} I-5) 8 - (VAc) 12
_{- PV14 :-( VAl) 76 - (} I-5) 12 - (VAc) 12
_{- PV15 :-( VAl) 81 - (} I-5) 15 - (VAc) 4
_{- PV16 :-( VAl) 55 - (} I-6) 44 - (VAc) 1
_{- PV17 :-( VAl) 42 - (} I-6) 56 - (VAc) 2
_{- PV18 :-( VAl) 27 - (} I-6) 61 - (VAc) 12
−

[0075] _{PV19 :-( VAl) 68 - (I} -7) 20 -
_{(VAc) 12 - PV20 :-( VAl} ) 65 - (I-7) 15 - (VAc) 20
_{- PV21 :-( VAl) 64 - (} I-7) 28 - (VAc) 8
_{- PV22 :-( VAl) 78 - (} I-8) 21 - (VAc) 1
_{-S-n-C 12 H 25} PV23 :-( VAl) 66 - (I-8) 30 - (VAc) 4
_{-S-n-C 12 H 25} PV24 :-( VAl) 53 - (I-8) 35 - (VAc) 12
_{-S-n-C 12 H 25} PV25 :-( VAl) 63 - (I-9) 25 - (VAc) 12
_{- PV26 :-( VAl) 80 - (} I-9) 18 - (VAc) 2
_{- PV27 :-( VAl) 46 - (} I-9) 34 - (VAc) 20
−

[0076] _{PV28 :-( VAl) 88 - (I} -10) 10 -
_{(VAc) 2 - PV29 :-( VAl} ) 67 - (I-10) 21 - (VAc) 12
_{- PV30 :-( VAl) 62 - (} I-10) 30 - (VAc) 8
_{- PV31 :-( VAl) 81 - (} I-11) 18 - (VAc) 1
_{- PV32 :-( VAl) 73 - (} I-11) 25 - (VAc) 2
_{- PV33 :-( VAl) 58 - (} I-11) 30 - (VAc) 12
_{- PV34 :-( VAl) 74 - (} I-12) 25 - (VAc) 1
_{- PV35 :-( VAl) 68 - (} I-12) 30 - (VAc) 2
-PV36:-(VAl) _52- (I-12) _40- (VAc) ₈
−

[0077] _{PV37 :-( VAl) 63 - (I} -13) 35 -
_{(VAc) 2 - PV38 :-( VAl} ) 55 - (I-13) 41 - (VAc) 4
_{- PV39 :-( VAl) 63 - (} I-13) 25 - (VAc) 12
_{- PV40 :-( VAl) 63 - (} I-14) 25 - (VAc) 12
-PV41:-(VAl) _40- (I-14) _40- (VAc) <sub>20
- PV42 :-( VAl) 48 - (</sub> I-14) 48 - (VAc) 4
_{- PV43 :-( VAl) 74 - (} I-15) 25 - (VAc) 1
_{- PV44 :-( VAl) 61 - (} I-15) 31 - (VAc) 8
_{- PV45 :-( VAl) 48 - (} I-15) 40 - (VAc) 12
−

[0078] _{PV46 :-( VAl) 86 - (I} -16) 12 -
_{(VAc) 2 - PV47 :-( VAl} ) 78 - (I-16) 18 - (VAc) 4
_{- PV48 :-( VAl) 68 - (} I-16) 24 - (VAc) 8
_{- PV49 :-( VAl) 76 - (} I-17) 22 - (VAc) 2
_{- PV50 :-( VAl) 58 - (} I-17) 30 - (VAc) 12
_{- PV51 :-( VAl) 50 - (} I-17) 35 - (VAc) 15
_{- PV52 :-( VAl) 78 - (} I-18) 10 - (VAc) 12
_{- PV53 :-( VAl) 70 - (} I-18) 18 - (VAc) 12
_{- PV54 :-( VAl) 57 - (} I-18) 31 - (VAc) 12
−

A polymerizable group may be introduced into the modified polyvinyl alcohol. When a modified polyvinyl alcohol having a polymerizable group and a liquid crystal molecule having a polymerizable group are used in combination, the modified polyvinyl alcohol and the liquid crystal molecule are chemically bonded via an interface between the liquid crystal layer and the liquid crystal alignment film. Can be. Thereby, the durability of the liquid crystal element using the liquid crystal alignment film can be improved. The polymerizable group is introduced into the modified polyvinyl alcohol as a repeating unit having a polymerizable group in the side chain, or two, three or three aromatic rings or aromatic heterocycles are added to the side chain in the above (1). A polymerizable group is introduced into the four repeating units. (2) a repeating unit having a polymerizable group in a side chain, and (3) a repeating unit having two, three or four aromatic rings or aromatic heterocycles in a side chain and a polymerizable group. explain.

(2) Repeating unit having a polymerizable group in the side chain The polymerizable group is subjected to a polymerization reaction with a polymerizable group (Q) of a liquid crystal molecule described later to convert the liquid crystal molecule and the modified polyvinyl alcohol into a liquid crystal. Chemical bonding is performed through the interface between the layer and the liquid crystal alignment film. Therefore, the type of the polymerizable group is determined according to the type of the polymerizable group (Q) of the liquid crystal molecule described below. As described below, the polymerizable group (Q) of the liquid crystal molecule includes an unsaturated polymerizable group (Q1 to Q7 described below), an epoxy group (Q
7) or an aziridinyl group (Q8), more preferably an unsaturated polymerizable group, and most preferably an ethylenically unsaturated polymerizable group (Q1 to Q6). Similarly, the polymerizable group of the modified polyvinyl alcohol is preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, and an ethylenically unsaturated polymerizable group. Is most preferred.

It is preferable that the main chain and the polymerizable group are not directly linked but are linked via a linking group. Examples of linking groups include -O
-, -O-CO-, -O-CO-NH-, -O-CO-
NH-alkylene group-, -O-CO-NH-alkylene group-O-,-O-CO-NH-alkylene group-CO-O
-, -O-CO-NH-alkylene group -O-CO-,-
O-CO-NH-alkylene group -CO-NH-, -O-
CO-alkylene group -O-CO-, -O-CO-arylene group -O-alkylene group -O-CO-, -O-CO-
Arylene group -O-alkylene group -O-, -O-CO-
Arylene group -O-alkylene group- and -O-alkylene group -O-CO- (the left side is bonded to the main chain,
The right side binds to the polymerizable group). The alkylene group may have a branched or cyclic structure. The number of carbon atoms of the alkylene group is preferably 1 to 30, more preferably 1 to 20, still more preferably 1 to 15, and most preferably 1 to 12. The arylene group is preferably phenylene or naphthylene, more preferably phenylene, and most preferably p-phenylene. The arylene group may have a substituent. Examples of the substituent of the arylene group are the same as the examples of the substituent of the aromatic ring and the aromatic heterocyclic ring in (1). The side chain may have two or more polymerizable groups. The repeating unit having a polymerizable group in the side chain is preferably represented by the following formula (II).

[0082]

Embedded image

In the formula (II), L ¹¹ is a single bond, —C
O-, -CO-NH-, -CO-NH-alkylene group-, -CO-NH-alkylene group -O-, -CO-NH
-Alkylene group -CO-O-, -CO-NH-alkylene group -O-CO-, -CO-NH-alkylene group -CO
-NH-, -CO-alkylene group -O-CO-, -CO
-Arylene group -O-alkylene group -O-CO-, -C
O-arylene group -O-alkylene group -O-, -CO-
It is a linking group selected from the group consisting of an arylene group -O-alkylene group- and -alkylene group -O-CO-.
-CO-NH-alkylene group-, -CO-NH-alkylene group -O-, -CO-NH-alkylene group -O-CO
-, -CO-arylene group -O-alkylene group -OC
O-, -CO-arylene group-O-alkylene group-O
-, -CO-arylene group -O-alkylene group- and -alkylene group -O-CO- are preferable, and -CO-NH
An -alkylene group -O-CO- is particularly preferred. The alkylene group may have a branched or cyclic structure.
The number of carbon atoms of the alkylene group is preferably 1 to 30, more preferably 1 to 20, still more preferably 1 to 15, and most preferably 1 to 12. The arylene group is preferably phenylene or naphthylene, more preferably phenylene, and most preferably p-phenylene. The arylene group may have a substituent. Examples of the substituent of the arylene group are the same as the examples of the substituent of the aromatic ring and the aromatic heterocyclic ring in (1). In the formula (II), Q is a polymerizable group. The polymerizable group is
As described above, the group is preferably the same as the polymerizable group (Q) of the liquid crystal molecule. Examples of the repeating unit having a polymerizable group in the side chain are shown below.

[0084]

Embedded image

[0085]

Embedded image

[0086]

Embedded image

[0087]

Embedded image

[0088]

Embedded image

[0089]

Embedded image

[0090]

Embedded image

[0091]

Embedded image

[0092]

Embedded image

[0093]

Embedded image

[0094]

Embedded image

(3) a repeating unit having two, three or four aromatic rings or aromatic heterocycles in the side chain and a polymerizable group; (1) an aromatic ring or aromatic property in the side chain In the repeating unit having two, three or four heterocycles, the above (2)
The polymerizable group described in (1) is introduced. The polymerizable group is preferably a substituent of an aromatic ring or an aromatic heterocyclic ring,
More preferably, it is a substituent of the most terminal aromatic ring or aromatic heterocyclic ring. It is preferable that the aromatic ring or the aromatic heterocyclic ring and the polymerizable group are not directly linked but are linked via a linking group. Examples of linking groups include -O-, -CO
-, -O-CO-, -CO-O-, -O-CO-O-,
-CO-NH-, -alkylene group-, -O-alkylene group- and -alkylene group -O- (the left side is bonded to an aromatic ring or an aromatic heterocyclic ring, and the right side is bonded to a polymerizable group. Do). The alkylene group may have a branched or cyclic structure. The number of carbon atoms in the alkylene group is
It is preferably 1 to 30, more preferably 1 to 20, still more preferably 1 to 15, and most preferably 1 to 12. The aromatic ring or aromatic heterocyclic ring may have two or more polymerizable groups as substituents. The repeating unit having two, three or four aromatic rings or aromatic heterocycles in the side chain and a polymerizable group is preferably represented by the following formula (III).

[0096]

Embedded image

In the formula (III), L ²¹ is a single bond, —C
O-, -CO-NH-, -alkylene group-, -CO-N
H-alkylene group-, -CO-NH-alkylene group-O
-, -CO-NH-alkylene group -CO-O- and-
It is a linking group selected from the group consisting of a CO-NH-alkylene group -CO-NH-. -CO-, -CO-NH- and -alkylene group- are preferable, and -CO-NH- is particularly preferable. The alkylene group may have a branched or cyclic structure. The number of carbon atoms in the alkylene group is 1
It is preferably from 30 to 30, more preferably from 1 to 20, still more preferably from 1 to 15, and most preferably from 1 to 12. In the formula (III), L ²² , L ²³ , L ²⁴ and L ²⁵ each independently represent a single bond, —O—, —CO—, —O—CO—, —CO
It is a linking group selected from the group consisting of -O-, -O-CO-O-, -CO-NH-, -alkylene group-, -O-alkylene group- and -alkylene group -O-. L ² , L
It is particularly preferred that at least one of ³ and L ⁴ is a single bond.

In the formula (III), Ar ²¹ , Ar ²² , Ar
²³ and Ar ²⁴ are each independently an aromatic ring or an aromatic heterocyclic ring. It is preferably an aromatic ring,
More preferably, it is a benzene ring. Ar ²¹ , Ar
It is particularly preferred that ²² and Ar ²³ are p-phenylene. The aromatic ring and the aromatic heterocyclic ring may have a substituent. Examples of the substituent are the same as the examples of the substituent of the aromatic ring and the aromatic heterocyclic ring in (1). Formula (III)
In the formula, m and n are 0 or 1. m is preferably 0 or 1, and n is preferably 0 (the number of aromatic rings or aromatic heterocycles is 2 or 3), and m and n are each 0 (an aromatic ring or an aromatic heterocycle). Most preferably, the number is 2). In the formula (III), p is
1, 2, or 3. p is preferably 1 or 2, and more preferably 1. Hereinafter, examples of the repeating unit having two, three, or four aromatic rings or aromatic heterocycles in the side chain and a polymerizable group are shown.

[0099]

Embedded image

[0100]

Embedded image

[0101]

Embedded image

[0102]

Embedded image

[0103]

Embedded image

[0104]

Embedded image

[0105]

Embedded image

[0106]

Embedded image

[0107]

Embedded image

[0108]

Embedded image

[0109]

Embedded image

(2) When a repeating unit having a polymerizable group in the side chain is introduced into the modified polyvinyl alcohol, the modified polyvinyl alcohol may contain 0.1 to 10 mol% of the repeating unit having a polymerizable group in the side chain. More preferably, it is contained in the range of 3 to 50 mol%. (3) When a repeating unit having two, three or four aromatic rings or aromatic heterocycles and a polymerizable group in the side chain is used, the modified polyvinyl alcohol has an aromatic ring or an aromatic ring in the side chain. The repeating unit having 2, 3, or 4 heterocyclic rings and a polymerizable group is preferably contained in an amount of 2 to 80 mol%, more preferably 3 to 50 mol%.

(1) a repeating unit having two, three or four aromatic rings or aromatic heterocycles in the side chain;
A modified polyvinyl alcohol containing a repeating unit having a polymerizable group in a side chain is represented by the following formula (PVII). (PVII)-(VAl) x- (I) a- (II) b- (VAc) y- wherein VAl is a repeating unit derived from vinyl alcohol; I is an aromatic ring in the side chain. Or a repeating unit having two, three or four aromatic heterocycles; II is a repeating unit having a polymerizable group in a side chain; and VAc is a repeating unit derived from vinyl acetate. X is 20 to 95 mol% (preferably 30 to 95 mol%); a is 2 to 80 mol% (preferably 3 to 50 mol%); b is 0.1 to 1 mol%
0 mol% (preferably 0.2-5 mol%); and y is 0-30 mol% (preferably 1-20 mol%).

(3) A modified polyvinyl alcohol containing a repeating unit having two, three or four aromatic rings or aromatic heterocycles in the side chain and a polymerizable group is represented by the following formula (PV
III). (PVIII)-(VAl) x- (III) c- (VAc) y- wherein VAl is a repeating unit derived from vinyl alcohol; III is an aromatic ring or an aromatic heterocyclic group in the side chain. A repeating unit having 2, 3, or 4 rings and a polymerizable group; x is 20 to 95 mol% (preferably 30 to 95 mol%); c is 2 to 80 mol%
And y is 0 to 30 mol% (preferably 1 to 20 mol%).

A modified polyvinyl alcohol obtained by combining the above repeating units may be used. That is, (1)
A modified polyvinyl alcohol having a repeating unit of (2) and (3), or a modified polyvinyl alcohol having a repeating unit of (1), (2) and (3). It can also be used. A group different from the repeating unit may be bonded to the terminal of the modified polyvinyl alcohol having a polymerizable group. Examples of the terminal group include an alkylthio group. Hereinafter, examples of the modified polyvinyl alcohol having a polymerizable group will be described. The ratio of repeating units is mol%
It is.

[0114] _{PV101 :-( VAl) 61 - (I} -13)
_{25 - (II-1) 2} - (VAc) 12 - PV102 :-( VAl) 56 - (I-13) 30 - (II-
_{1) 2 - (VAc) 12} - PV103 :-( VAl) 51 - (I-13) 30 - (II-
_{1) 5 - (VAc) 12} - PV104 :-( VAl) 68 - (I-13) 25 - (II-
1) _2- (VAc) ₅ -PV105:-(VAl) _64- (I-13) _30- (II-
_{1) 5 - (VAc) 1} - PV106 :-( VAl) 61 - (I-13) 30 - (II-
_{2) 2 - (VAc) 12} - PV107 :-( VAl) 61 - (I-13) 30 - (II-
_{4) 2 - (VAc) 12} - PV108 :-( VAl) 61 - (I-13) 30 - (II-
_{5) 2 - (VAc) 12} - PV109 :-( VAl) 61 - (I-14) 30 - (II-
_{1) 2 - (VAc) 12} - PV110 :-( VAl) 61 - (I-20) 30 - (II-
_{1) 2 - (VAc) 12} -

[0115] _{PV111 :-( VAl) 63 - (III} -9)
_{25 - (VAc) 12 - PV112} :-( VAl) 56 - (III-9) 30 - (VA
_{c) 12 - PV113 :-( VAl)} 67 - (III-9) 30 - (VA
_{c) 1 - PV114 :-( VAl)} 65 - (III-9) 30 - (VA
_{c) 5 - PV115 :-( VAl)} 48 - (III-9) 40 - (VA
_{c) 12 - PV116 :-( VAl)} 63 - (III-10) 25 - (VA
_{c) 12 - PV117 :-( VAl)} 56 - (III-10) 30 - (VA
_{c) 12 - PV118 :-( VAl)} 67 - (III-10) 30 - (VA
_{c) 1 - PV119 :-( VAl)} 65 - (III-10) 30 - (VA
_{c) 5 - PV120 :-( VAl)} 48 - (III-10) 40 - (VA
c) ₁₂ −

[0116] _{PV121 :-( VAl) 61 - (I} -13)
_{25 - (III-9) 2} - (VAc) 12 - PV122 :-( VAl) 56 - (I-13) 30 - (III-
_{9) 2 - (VAc) 12} - PV123 :-( VAl) 46 - (I-13) 40 - (III-
_{9) 2 - (VAc) 12} - PV124 :-( VAl) 56 - (I-16) 30 - (III-
_{1) 2 - (VAc) 12} - PV125 :-( VAl) 48 - (I-16) 35 - (III-
_{2) 5 - (VAc) 12} - PV126 :-( VAl) 56 - (I-20) 25 - (III-
_{9) 7 - (VAc) 12} - PV127 :-( VAl) 49 - (I-20) 40 - (III-1
_{0) 10 - (VAc) 1} - PV128 :-( VAl) 78 - (I-38) 15 - (III-
_{9) 2 - (VAc) 5} - PV129 :-( VAl) 58 - (I-38) 25 - (III-1
_{0) 5 - (VAc) 12} - PV130 :-( VAl) 48 - (I-52) 30 - (III-1
_{1) 10 - (VAc) 12} -

[0117] _{PV131 :-( VAl) 61 - (II} -1)
_{2 - (III-9) 25} - (VAc) 12 - PV132 :-( VAl) 53 - (II-1) 5 - (III-
_{9) 30 - (VAc) 12} - PV133 :-( VAl) 50 - (II-1) 10 - (III-
_{9) 35 - (VAc) 5} - PV134 :-( VAl) 53 - (II-1) 2 - (III-
_{9) 40 - (VAc) 5} - PV135 :-( VAl) 61 - (II-1) 2 - (III-1
_{0) 25 - (VAc) 12} - PV136 :-( VAl) 53 - (II-2) 5 - (III-1
_{0) 30 - (VAc) 12} - PV137 :-( VAl) 50 - (II-4) 10 - (III-1
_{0) 35 - (VAc) 5} - PV138 :-( VAl) 53 - (II-1) 5 - (III-1
_{0) 30 - (VAc) 12} - PV139 :-( VAl) 61 - (II-1) 2 - (III-1
_{1) 25 - (VAc) 12} - PV140 :-( VAl) 56 - (II-4) 2 - (III-1
_{1) 30 - (VAc) 12} -

[0118] _{PV141 :-( VAl) 61 - (I} -13) 23 - (II
_{-1) 2 - (III-9} ) 2 - (VAc) 12 - PV142 :-( VAl) 61 - (I-13) 25 - (II-1) 1 - (III
_{-9) 1 - (VAc) 12} - PV143 :-( VAl) 56 - (I-13) 30 - (II-1) 1 - (III
_{-9) 1 - (VAc) 12} - PV144 :-( VAl) 51 - (I-13) 35 - (II-1) 1 - (III
_{-9) 1 - (VAc) 12} - PV145 :-( VAl) 57 - (I-13) 40 - (II-1) 0.5 - (II
_{I-9) 0.5 - (VAc} ) 12 - PV146 :-( VAl) 56 - (I-13) 30 - (II-2) 1 - (III
_{-10) 1 - (VAc) 12} - PV147 :-( VAl) 51 - (I-13) 30 - (II-4) 1 - (III
_{-10) 5 - (VAc) 12} - PV148 :-( VAl) 56 - (I-14) 30 - (II-1) 1 - (III
_{-9) 1 - (VAc) 12} - PV149 :-( VAl) 56 - (I-16) 30 - (II-1) 1 - (III
_{-9) 1 - (VAc) 12} - PV150 :-( VAl) 56 - (I-38) 30 - (II-1) 1 - (III
_{-9) 1 - (VAc) 12} -

A hydrophilic group may be introduced into modified polyvinyl alcohol. By introducing a hydrophilic group into modified polyvinyl alcohol, an alignment film can be formed using an aqueous solvent. Even if polyvinyl alcohol is slightly denatured,
Since it is a polymer containing a large number of hydroxyl groups exhibiting extremely strong hydrophilicity, it is completely unexpected that the hydrophilicity becomes insufficient (becomes water-insoluble). The hydrophilic group is introduced into the modified polyvinyl alcohol as a repeating unit having a hydrophilic group in the side chain, or two, three or three aromatic rings or aromatic heterocycles are added to the side chain in the above (1). A hydrophilic group is introduced into the four repeating units. (4) a repeating unit having a hydrophilic group in a side chain, and (5) a repeating unit having two, three or four aromatic rings or aromatic heterocycles in a side chain and a hydrophilic group. explain.

(2) Repeating Unit Having a Hydrophilic Group on the Side Chain The hydrophilic group needs to exhibit a higher hydrophilicity than the hydroxyl group of polyvinyl alcohol. The repeating unit having a group showing a stronger hydrophilicity than the hydroxyl group of polyvinyl alcohol is a modified polyvinyl using the repeating unit, instead of a modified polyvinyl alcohol using a repeating unit derived from vinyl alcohol in place of the repeating unit. Alcohol means a repeating unit having higher solubility in water. As such a hydrophilic group, an anionic group, a cationic group or a nonionic group can be used. Examples of the anionic group include a carboxylic acid group and a sulfonic acid group. Alcoholates and phenolates can also function as anionic groups. Examples of cationic groups include
Ammonium groups are included. An amino group, an amide group, a sulfonamide group, a hydrazino group, a hydrazide group, a carbamoyl group or a sulfamoyl group can also function as a cationic group. The anionic group and the cationic group are preferably in a salt state. As a counter ion of the anionic group, an alkali metal ion or an ammonium ion is preferable. As the counter ion of the cationic group, a halogen ion is preferable. Examples of the nonionic group (a nonionic group showing stronger hydrophilicity than a hydroxyl group) include a group composed of polyethylene glycol. Examples of the hydrophilic group are shown below.

[0121]

Embedded image

[0122]

Embedded image

[0123]

Embedded image

[0124]

Embedded image

[0125]

Embedded image

It is preferable that the main chain and the hydrophilic group are not directly linked but are linked via a linking group. Examples of linking groups include -O
-, -O-CO-, -O-CO-NH-, -O-CO-
NH-alkylene group-, -O-CO-NH-alkylene group-O-,-O-CO-NH-alkylene group-CO-O
-, -O-CO-NH-alkylene group -O-CO-,-
O-CO-NH-alkylene group -CO-NH-, -O-
CO-NH-arylene group-, -O-CO-alkylene group-, -O-CO-alkenylene group-, -O-CO-arylene group-, -O-CO-alkylene group-O-CO
-, -O-CO-arylene group -O-alkylene group -O
-CO-, -O-CO-arylene group -O-alkylene group -O-, -O-CO-arylene group -O-alkylene group-, -O-alkylene group- and -O-alkylene group -O-CO -(The left side binds to the main chain and the right side binds to the hydrophilic group).

The alkylene group may have a branched or cyclic structure. The number of carbon atoms in the alkylene group is 1
It is preferably from 30 to 30, more preferably from 1 to 20, still more preferably from 1 to 15, and most preferably from 1 to 12. The alkenylene group may have a branch. The alkenylene group preferably has 2 to 30 carbon atoms, and preferably has 2 to 30 carbon atoms.
It is more preferably from 20 to 20, still more preferably from 2 to 15, and most preferably from 2 to 12. The arylene group is preferably phenylene or naphthylene, more preferably phenylene, and most preferably p-phenylene. The arylene group may have a substituent. Examples of the substituent of the arylene group are the same as the examples of the substituent of the aromatic ring and the aromatic heterocyclic ring in (1). The side chain may have two or more hydrophilic groups. Two or more kinds of hydrophilic groups can be used in combination (that is, an amphoteric group is used). The repeating unit having a hydrophilic group in the side chain is preferably represented by the following formula (IV).

[0128]

Embedded image

In the formula (IV), L ³¹ is a single bond, -C
O-, -CO-NH-, -CO-NH-alkylene group-, -CO-NH-alkylene group -O-, -CO-NH
-Alkylene group -CO-O-, -CO-NH-alkylene group -O-CO-, -CO-NH-alkylene group -CO
-NH-, -CO-NH-arylene group-, -CO-alkylene group-, -CO-alkenylene group-, -CO-arylene group-, -CO-alkylene group -O-CO-,-
CO-arylene group-O-alkylene group-O-CO-,
-CO-arylene group -O-alkylene group -O-, -C
It is a linking group selected from the group consisting of O-arylene group-O-alkylene group-, -alkylene group- and -alkylene group-O-CO-.

The above alkylene group may have a branched or cyclic structure. The number of carbon atoms in the alkylene group is 1
It is preferably from 30 to 30, more preferably from 1 to 20, still more preferably from 1 to 15, and most preferably from 1 to 12. The alkenylene group may have a branch. The alkenylene group preferably has 2 to 30 carbon atoms, and preferably has 2 to 30 carbon atoms.
It is more preferably from 20 to 20, still more preferably from 2 to 15, and most preferably from 2 to 12. The arylene group is preferably phenylene or naphthylene, more preferably phenylene, and most preferably p-phenylene. The arylene group may have a substituent. Examples of the substituent of the arylene group are the same as the examples of the substituent of the aromatic ring and the aromatic heterocyclic ring in (1). In the formula (IV), Hy is a group showing a higher hydrophilicity than the hydroxyl group of polyvinyl alcohol. Examples of the hydrophilic group (Hy) are as described above. Hereinafter, examples of the repeating unit having a hydrophilic group in the side chain are shown.

[0131]

Embedded image

[0132]

Embedded image

[0133]

Embedded image

[0134]

Embedded image

[0135]

Embedded image

[0136]

Embedded image

[0137]

Embedded image

[0138]

Embedded image

[0139]

Embedded image

[0140]

Embedded image

[0141]

Embedded image

[0142]

Embedded image

[0143]

Embedded image

[0144]

Embedded image

[0145]

Embedded image

[0146]

Embedded image

[0147]

Embedded image

[0148]

Embedded image

[0149]

Embedded image

[0150]

Embedded image

[0151]

Embedded image

[0152]

Embedded image

[0153]

Embedded image

(5) A repeating unit having two, three or four aromatic rings or aromatic heterocycles in the side chain and a hydrophilic group. (1) An aromatic ring or aromatic group in the side chain. A hydrophilic group is introduced into a repeating unit having two, three or four heterocycles. The hydrophilic group is preferably a group (Hy) exhibiting stronger hydrophilicity than the hydroxyl group of the polyvinyl alcohol described in (4). The hydrophilic group is preferably a substituent of an aromatic ring or an aromatic heterocyclic ring, and more preferably a substituent of an aromatic ring or an aromatic heterocyclic ring closest to the main chain. The aromatic ring or aromatic heterocyclic ring and the hydrophilic group may be linked via a linking group. Examples of the linking group include -O-, -CO-, -O-CO-, -CO-O-,
-O-CO-O-, -CO-NH-, -alkylene group-, -O-alkylene group- and -alkylene group -O-
(The left side is bonded to an aromatic ring or an aromatic heterocyclic ring, and the right side is bonded to a hydrophilic group). The alkylene group may have a branched or cyclic structure. The alkylene group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and more preferably 1 to 15 carbon atoms.
Is more preferable, and most preferably 1 to 12. The aromatic ring or aromatic heterocyclic ring may have two or more hydrophilic groups as substituents. The repeating unit having two, three or four aromatic rings or aromatic heterocycles in the side chain and a hydrophilic group is preferably represented by the following formula (V).

[0155]

Embedded image

In the formula (V), L ⁴¹ is a single bond, -C
O-, -CO-NH-, -alkylene group-, -CO-N
H-alkylene group-, -CO-NH-alkylene group-O
-, -CO-NH-alkylene group -CO-O- and-
It is a linking group selected from the group consisting of a CO-NH-alkylene group -CO-NH-. -CO-, -CO-NH- and -alkylene group- are preferable, and -CO-NH- is particularly preferable. The alkylene group may have a branched or cyclic structure. The number of carbon atoms in the alkylene group is 1
It is preferably from 30 to 30, more preferably from 1 to 20, still more preferably from 1 to 15, and most preferably from 1 to 12. In the formula (V), L ⁴² , L ⁴³ , L ⁴⁴ and L ⁴⁵ each independently represent a single bond, —O—, —CO—, —O—CO—, —CO
It is a linking group selected from the group consisting of -O-, -O-CO-O-, -CO-NH-, -alkylene group-, -O-alkylene group- and -alkylene group -O-. L ⁴² , L
At least one of ⁴³ and L ⁴⁴ are each particularly preferably a single bond.

In the formula (V), Ar ⁴¹ , Ar ⁴² , Ar
⁴³ and Ar ⁴⁴ are each independently an aromatic ring or an aromatic heterocyclic ring. It is preferably an aromatic ring,
More preferably, it is a benzene ring. Ar ⁴¹ , Ar
⁴² and Ar ⁴³ are particularly preferably p-phenylene (for Ar ⁴¹ , the relationship between L ⁴¹ and L ⁴² , L ⁴³ or L ⁴⁴ is para). The aromatic ring and the aromatic heterocyclic ring may have a substituent. Examples of substituents are
It is the same as the example of the substituent of the aromatic ring and the aromatic hetero ring of (1). In the formula (V), Hy is a hydrophilic group. The definition and examples of the hydrophilic group (Hy) are the same as those of the repeating unit (2) having a hydrophilic group in the side chain. In the formula (V), m and n are 0 or 1. m
Is preferably 0 or 1, and n is 0 (the number of aromatic rings or aromatic heterocycles is 2 or 3), and m and n
Is most preferably 0 (the number of aromatic rings or aromatic heterocycles is 2). In equation (V), p
Is 1, 2 or 3. p is preferably 1 or 2, and more preferably 1. Examples of the repeating unit having two, three or four aromatic rings or aromatic heterocycles and a hydrophilic group in the side chain are shown below.

[0158]

Embedded image

[0159]

Embedded image

[0160]

Embedded image

[0161]

Embedded image

[0162]

Embedded image

[0163]

Embedded image

[0164]

Embedded image

[0165]

Embedded image

[0166]

Embedded image

[0167]

Embedded image

[0168]

Embedded image

[0169]

Embedded image

[0170]

Embedded image

[0171]

Embedded image

[0172]

Embedded image

[0173]

Embedded image

[0174]

Embedded image

[0175]

Embedded image

[0176]

Embedded image

[0177]

Embedded image

[0178]

Embedded image

[0179]

Embedded image

[0180]

Embedded image

[0181]

Embedded image

[0182]

Embedded image

[0183]

Embedded image

[0184]

Embedded image

[0185]

Embedded image

[0186]

Embedded image

(4) When a repeating unit having a hydrophilic group in the side chain is introduced into the modified polyvinyl alcohol, the modified polyvinyl alcohol preferably contains 3 to 90 mol% of a repeating unit having a hydrophilic group in the side chain. 4 to 7
More preferably, it is contained in the range of 0 mol%. (5) When a repeating unit having two, three or four aromatic rings or aromatic heterocycles and a hydrophilic group in the side chain is used, the modified polyvinyl alcohol has an aromatic ring or an aromatic ring in the side chain. The repeating unit having 2, 3, or 4 hydrophilic heterocycles and a hydrophilic group is preferably contained in an amount of 2 to 80 mol%, more preferably 3 to 50 mol%.

(4) A modified polyvinyl alcohol containing a repeating unit having a hydrophilic group in a side chain is represented by the following formula (PVIV)
Expressed by (PVIV)-(VAl) x- (I) a- (IV) d- (VAc) y- wherein, VAl is a repeating unit derived from vinyl alcohol; I is an aromatic ring in the side chain. Or a repeating unit having 2, 3, or 4 aromatic heterocycles; IV is a repeating unit having a hydrophilic group in a side chain; VAc is a repeating unit derived from vinyl acetate X is 20 to 95 mol% (preferably 30 to 95 mol%); a is 2 to 80 mol% (preferably 3 to 50 mol%); d is 3 to 90 mol% ( Preferably 4 to 70 mol%); and
y is 0 to 30 mol% (preferably 1 to 20 mol%)
It is.

A modified polyvinyl alcohol containing a repeating unit having two, three or four aromatic rings or aromatic heterocycles in the side chain and a hydrophilic group is represented by the following formula (PVV). (PVV)-(VAl) x- (V) e- (VAc) y- wherein VA1 is a repeating unit derived from vinyl alcohol; V is an aromatic ring or an aromatic heterocyclic group in the side chain. A repeating unit having two, three or four rings and a hydrophilic group; x is 20 to 95 mol% (preferably 30 to 95 mol%); e is 2 to 80 mol% (Preferably 3-50 mol%); and
y is 0 to 30 mol% (preferably 1 to 20 mol%)
It is.

A modified polyvinyl alcohol obtained by combining the above repeating units may be used. That is,
Modified polyvinyl alcohol having a repeating unit of (1) and (5), modified polyvinyl alcohol having a repeating unit of (4) and (5), or modified having a repeating unit of (1), (4) and (5) Polyvinyl alcohol can also be used. A group different from the repeating unit may be bonded to the terminal of the modified polyvinyl alcohol having a hydrophilic group. Examples of the terminal group include an alkylthio group. Hereinafter, examples of the modified polyvinyl alcohol having a hydrophilic group will be described. The ratio of the repeating unit is mol%.

[0191] _{PV201 :-( VAl) 23 - (I} -13)
_{25 - (IV-5) 40} - (VAc) 12 - PV202 :-( VAl) 23 - (I-14) 25 - (IV-
_{5) 40 - (VAc) 12} - PV203 :-( VAl) 23 - (I-13) 25 - (IV-1
_{4) 40 - (VAc) 12} - PV204 :-( VAl) 23 - (I-13) 30 - (IV-
_{5) 35 - (VAc) 12} - PV205 :-( VAl) 3 - (I-13) 40 - (IV-1
_{4) 45 - (VAc) 12} - PV206 :-( VAl) 23 - (I-13) 30 - (IV-1
_{9) 35 - (VAc) 12} - PV207 :-( VAl) 23 - (I-13) 30 - (IV-2
_{2) 35 - (VAc) 12} - PV208 :-( VAl) 23 - (I-13) 30 - (IV-2
_{6) 35 - (VAc) 12} - PV209 :-( VAl) 23 - (I-20) 30 - (IV-
_{3) 35 - (VAc) 12} - PV210 :-( VAl) 23 - (I-27) 30 - (IV-1
_{1) 35 - (VAc) 12} -

[0192] _{PV211 :-( VAl) 63 - (V} -1)
_{25 - (VAc) 12 - PV212} :-( VAl) 58 - (V-1) 30 - (VA
_{c) 12 - PV213 :-( VAl)} 63 - (V-5) 25 - (VA
_{c) 12 - PV214 :-( VAl)} 58 - (V-5) 30 - (VA
_{c) 12 - PV215 :-( VAl)} 63 - (V-7) 25 - (VA
_{c) 12 - PV216 :-( VAl)} 58 - (V-7) 30 - (VA
_{c) 12 - PV217 :-( VAl)} 63 - (V-9) 25 - (VA
_{c) 12 - PV218 :-( VAl)} 58 - (V-9) 30 - (VA
_{c) 12 - PV219 :-( VAl)} 63 - (V-11) 25 - (VA
_{c) 12 - PV220 :-( VAl)} 58 - (V-11) 30 - (VA
c) ₁₂ −

[0193] _{PV221 :-( VAl) 22 - (I} -13)
_{30 - (V-1) 30} - (VAc) 12 - PV222 :-( VAl) 12 - (I-13) 30 - (V-
_{1) 40 - (VAc) 12} - PV223 :-( VAl) 22 - (I-13) 30 - (V-
_{5) 30 - (VAc) 12} - PV224 :-( VAl) 12 - (I-13) 30 - (V-
_{5) 40 - (VAc) 12} - PV225 :-( VAl) 22 - (I-13) 30 - (V-
_{7) 30 - (VAc) 12} - PV226 :-( VAl) 12 - (I-13) 30 - (V-
_{7) 40 - (VAc) 12} - PV227 :-( VAl) 22 - (I-13) 30 - (V-
_{9) 30 - (VAc) 12} - PV228 :-( VAl) 12 - (I-13) 30 - (V-
_{9) 40 - (VAc) 12} - PV229 :-( VAl) 22 - (I-13) 30 - (V-1
_{1) 30 - (VAc) 12} - PV230 :-( VAl) 12 - (I-13) 30 - (V-1
_{1) 40 - (VAc) 12} -

[0194] _{PV231 :-( VAl) 66 - (IV} -3)
_{2 - (V-2) 30} - (VAc) 2 - PV232 :-( VAl) 63 - (IV-3) 2 - (V-
_{3) 30 - (VAc) 5} - PV233 :-( VAl) 58 - (IV-3) 2 - (V-
_{4) 30 - (VAc) 10} - PV234 :-( VAl) 63 - (IV-3) 2 - (V-
_{8) 30 - (VAc) 5} - PV235 :-( VAl) 63 - (IV-4) 2 - (V-1
_{2) 30 - (VAc) 5} - PV236 :-( VAl) 63 - (IV-4) 2 - (V-1
_{9) 30 - (VAc) 5} - PV237 :-( VAl) 66 - (IV-4) 2 - (V-2
_{1) 30 - (VAc) 2} - PV238 :-( VAl) 66 - (IV-4) 2 - (V-2
_{3) 30 - (VAc) 2} - PV239 :-( VAl) 63 - (IV-19) 5 - (V-2
_{6) 30 - (VAc) 2} - PV240 :-( VAl) 63 - (IV-19) 5 - (V-2
9) _30- (VAc) _2-

[0195] _{PV241 :-( VAl) 23 - (I} -13) 30 - (IV
_{-5) 30 - (V-1} ) 5 - (VAc) 12 - PV242 :-( VAl) 18 - (I-13) 35 - (IV-5) 30 - (V-
_{1) 10 - (VAc) 12} - PV243 :-( VAl) 23 - (I-13) 30 - (IV-14) 30 - (V-
_{5) 5 - (VAc) 12} - PV244 :-( VAl) 13 - (I-13) 35 - (IV-14) 30 - (V-
_{5) 10 - (VAc) 12} - PV245 :-( VAl) 23 - (I-13) 30 - (IV-19) 30 - (V-
_{7) 5 - (VAc) 12} - PV246 :-( VAl) 13 - (I-13) 35 - (IV-19) 30 - (V-
7) _10- (VAc) ₁₂ -PV247:-(VAl) _30- (I-13) _30- (IV-22) _30- (V-
_{9) 5 - (VAc) 5} - PV248 :-( VAl) 23 - (I-14) 35 - (IV-3) 30 - (V-
_{9) 10 - (VAc) 2} - PV249 :-( VAl) 33 - (I-20) 30 - (IV-11) 30 - (V-1
_{1) 5 - (VAc) 2} - PV250 :-( VAl) 23 - (I-27) 35 - (IV-26) 30 - (V-1
1) _10- (VAc) _2-

The degree of polymerization of the modified polyvinyl alcohol is 2
00 to 5000, preferably 300 to 3
000 is preferred. The molecular weight of the modified polyvinyl alcohol is preferably from 9000 to 200,000, more preferably from 13,000 to 130,000. Two or more modified polyvinyl alcohols may be used in combination.

In the present invention, modified polyvinyl alcohol is used after being crosslinked. The cross-linking reaction is preferably performed simultaneously with or after the application of the coating liquid for the alignment film. Using the crosslinking agent, the modified polyvinyl alcohol can be crosslinked by reacting the hydroxyl group of the modified polyvinyl alcohol with the crosslinking agent. Examples of crosslinking agents include aldehydes, N-
Methylol compounds (eg, dimethylol urea, methylol dimethylhydantoin), dioxane (eg, 2,3-dihydroxy dioxane), carbenium, 2-naphthalate sulfonate, 1,1-bispyrrolidino-1-chloropyridinium, 1-morpholinocarbonyl- 3- (sulfonatoaminomethyl), an active vinyl compound (eg, 1,
3,5-triacryloyl-hexahydro-s-triazine, bis (vinylsulfone) methane, N, N′-methylenebis- [β- (vinylisulfonyl) propionamide), an active halogen compound (eg, 2,4-dichloro-) 6
-Hydroxy-s-triazine) and isoxazoles. Aldehydes (eg, formaldehyde,
Glyoxal, glutaraldehyde, malonaldehyde, phthalaldehyde, terephthalaldehyde, succinaldehyde, isophthalaldehyde, dialdehyde starch) are preferred, difunctional or higher aldehydes are more preferred, and bifunctional aldehydes are most preferred. The aldehyde undergoes an acetalization reaction with a hydroxyl group of the modified polyvinyl alcohol to crosslink the modified polyvinyl alcohol. A cross-linked repeating unit obtained by using a bifunctional aldehyde is represented by the following formula (VI).

[0198]

Embedded image

In the formula, L ⁵¹ is a linking group linking two aldehydes of a bifunctional aldehyde. The acetalization reaction between the hydroxyl group of the modified polyvinyl alcohol and the aldehyde proceeds under acidic conditions. To make the reaction conditions acidic, an inorganic acid (eg, sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid) or an organic acid (eg, dichloroacetic acid, trifluoroacetic acid, methanesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, Monochloroacetic acid) is preferably added to the coating solution for the alignment film. The amount of the crosslinking agent used is preferably 0.1 to 20% by weight of the coating amount of the alignment film.
More preferably, it is 5 to 15% by weight. In addition,
The amount of the cross-linking agent remaining in the alignment film without being reacted is preferably 1.0% by weight or less of the coating amount of the alignment film,
More preferably, it is 0.5% by weight or less.

The thickness of the liquid crystal alignment film is 0.1 to 10 μm
It is preferred that In forming the liquid crystal alignment film, a rubbing treatment is preferably performed. The rubbing treatment is performed by rubbing the surface of the film containing the modified polyvinyl alcohol several times in a certain direction with paper or cloth. After aligning the liquid crystalline molecules using the liquid crystal alignment film,
A liquid crystal layer may be formed by fixing liquid crystal molecules in the aligned state, and the liquid crystal layer may be transferred onto a substrate. The liquid crystalline molecules fixed in the alignment state can maintain the alignment state without the alignment film. The liquid crystal alignment film of the present invention is particularly effective when used for vertical alignment of discotic liquid crystal molecules.

[Substrate] The type of substrate is a liquid crystal element (substrate,
(A liquid crystal alignment film and a laminate of liquid crystal molecules). When a liquid crystal element is used as a liquid crystal cell, a glass substrate provided with a transparent electrode layer (eg, ITO) is generally used. Two substrates having the above-mentioned liquid crystal alignment film formed on the transparent electrode layer are prepared, arranged so that the liquid crystal alignment films face each other, and rod-like liquid crystal molecules (described later) are sealed in the gaps. To form The gap is formed by the spacer. When a liquid crystal element is used as an optical compensation sheet, a transparent polymer film is usually used as a substrate. The polymer film preferably has a small optical anisotropy. Being transparent means that the light transmittance is 80% or more. To be small in optical anisotropy, specifically, the in-plane retardation (Re) is preferably 10 nm or less, more preferably 5 nm or less. In addition, the retardation in the thickness direction (Rth)
Is preferably 40 nm or less, and more preferably 20 nm or less. The in-plane retardation (Re) and the retardation in the thickness direction (Rth) are respectively defined by the following equations. Re = (nx−ny) × d Rth = [{(nx + ny) / 2} −nz] × d where nx and ny are in-plane refractive indices of the transparent support, and nz is the thickness of the transparent support. Is the refractive index in the direction, and d is the thickness of the transparent support.

Depending on the type of display mode of the liquid crystal cell,
In some cases, an optically anisotropic polymer film is used as the substrate of the optical compensation sheet. That is, in some cases, the optical anisotropy of the liquid crystal layer is added to the optical anisotropy of the polymer film to correspond to the optical anisotropy of the liquid crystal cell (optical compensation). When an optically anisotropic polymer film is used for such a purpose, the in-plane retardation (Re) of the polymer film is preferably at least 20 nm, more preferably at least 30 nm. The retardation in the thickness direction (Rth) is 8
It is preferably at least 0 nm, more preferably at least 120 nm. The polymer forming the polymer film is determined depending on whether it is optically isotropic or optically anisotropic. When optical isotropy is required, glass or cellulose ester is generally used. When optical anisotropy is required, a synthetic polymer (eg, polycarbonate, polysulfone, polyethersulfone, polyacrylate, polymethacrylate, norbornene resin) is generally used. The optical anisotropy is obtained by stretching the synthetic polymer film.
Cellulose ester or synthetic polymer films are
It is preferably formed by a solvent casting method.
The thickness of the substrate of the optical compensation sheet is preferably from 20 to 500 μm, more preferably from 50 to 200 μm. In order to improve the adhesion between the substrate of the optical compensation sheet and the layer provided thereon (adhesive layer, alignment film or optically anisotropic layer), the transparent support is subjected to surface treatment (eg, glow discharge treatment, corona discharge treatment). , Ultraviolet (UV) treatment,
Flame treatment). An adhesive layer (undercoat layer) may be provided on the transparent support.

[Liquid Crystal Layer] The liquid crystal layer is formed from liquid crystal molecules. The above-mentioned liquid crystal alignment film has a function of aligning liquid crystal molecules substantially vertically at an average tilt angle in the range of 50 to 90 degrees. As the liquid crystal molecules, rod-shaped liquid crystal molecules or discotic liquid crystal molecules are preferable. As described above, the tilt angle of the liquid rod-like liquid crystal molecules means the angle between the major axis direction of the rod-like liquid crystal molecules and the substrate plane, and the tilt angle of the discotic liquid crystal molecules is the disc surface of the discotic liquid crystal molecules. And the plane plane of the substrate. When the liquid crystal element is used as a liquid crystal cell, it is particularly preferable to use rod-like liquid crystal molecules. Examples of rod-like liquid crystal molecules include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, and alkoxy-substituted phenylpyrimidines. , Phenyldioxane, tolan and alkenylcyclohexylbenzonitrile are preferably used. As a liquid crystal cell in which rod-like liquid crystal molecules are substantially vertically aligned, VA (Vertically A
A liquid crystal cell in a ligned mode is typical. For a liquid crystal display device using a VA mode liquid crystal cell, see Nikkei Micro Device No. 136, 147 (1996), JP-A-2-176625 and Patent No. 2866.
No. 372.

When the liquid crystal element is used as an optical compensation sheet, rod-like liquid crystal molecules or discotic liquid crystal molecules can be preferably used. It is particularly preferable to use discotic liquid crystal molecules. The liquid crystalline molecules used in the optical compensation sheet are preferably fixed in a substantially aligned state, and more preferably fixed by polymerization. Discotic liquid crystalline molecules are described in various literatures (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vo.
l. 71, page 111 (1981); edited by The Chemical Society of Japan, quarterly chemistry review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10, Section 2
(1994); B. Kohne et al., Angew. Chem. Soc. Chem. C
omm., page 1794 (1985); J. Zhang et al., J. Am. Che
m. Soc., vol. 116, page 2655 (1994)). Regarding the polymerization of discotic liquid crystalline molecules,
It is described in JP-A-8-27284. In order to fix the discotic liquid crystal molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystal molecules. However, when a polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain an oriented state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Therefore, the discotic liquid crystal molecule is preferably a compound represented by the following formula.

D (-LQ) _{n wherein} D is a discotic core; L is a divalent linking group; Q is a polymerizable group; and n is an integer of 4-12. is there. An example of the discotic core (D) of the above formula is shown below. In each of the following examples, LQ (or QL) means a combination of a divalent linking group (L) and a polymerizable group (Q).

[0206]

Embedded image

[0207]

Embedded image

[0208]

Embedded image

[0209]

Embedded image

[0210]

Embedded image

[0211]

Embedded image

[0212]

Embedded image

[0213]

Embedded image

[0214]

Embedded image

In the above formula, the divalent linking group (L) is
Alkylene group, alkenylene group, arylene group, -CO
It is preferably a divalent linking group selected from the group consisting of-, -NH-, -O-, -S- and a combination thereof. The divalent linking group (L) is an alkylene group, an alkenylene group, an arylene group, -CO-, -NH-, -O-
And a group obtained by combining at least two divalent groups selected from the group consisting of and -S-.
The divalent linking group (L) is most preferably a group obtained by combining at least two divalent groups selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, -CO- and -O-. The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The arylene group preferably has 6 to 10 carbon atoms. The alkylene group, alkenylene group and arylene group may have a substituent (eg, an alkyl group, a halogen atom, a cyano, an alkoxy group, an acyloxy group). Examples of the divalent linking group (L) are shown below. The left side is bonded to the discotic core (D), and the right side is bonded to the polymerizable group (Q). AL represents an alkylene group or an alkenylene group, and AR represents an arylene group.

L1: -AL-CO-O-AL- L2: -AL-CO-O-AL-O- L3: -AL-CO-O-AL-O-AL- L4: -AL-CO-O -AL-O-CO-L5: -CO-AR-O-AL-L6: -CO-AR-O-AL-O-L7: -CO-AR-O-AL-O-CO-L8: -CO -NH-AL-L9: -NH-AL-O-L10: -NH-AL-O-CO-L11: -O-AL-L12: -O-AL-O-

L13: -O-AL-O-CO- L14: -O-AL-O-CO-NH-AL- L15: -O-AL-S-AL- L16: -O-CO-AL-AR -O-AL-O-CO-L17: -O-CO-AR-O-AL-CO-L18: -O-CO-AR-O-AL-O-CO-L19: -O-CO-AR- O-AL-O-AL-OC
O-L20: -O-CO-AR-O-AL-O-AL-OA
L-O-CO-L21: -S-AL-L22: -S-AL-O-L23: -S-AL-O-CO-L24: -S-AL-S-AL-L25: -S-AR -AL-

In order to optically compensate for a liquid crystal cell in which rod-like liquid crystal molecules are twisted in the STN mode, it is preferable that the discotic liquid crystal molecules are also twisted. When an asymmetric carbon atom is introduced into the AL (alkylene group or alkenylene group), the discotic liquid crystal molecule can be twisted and aligned in a helical manner. Further, even when a compound (chiral agent) having an asymmetric carbon atom and exhibiting optical activity is added to the optically anisotropic layer, the discotic liquid crystal molecules can be twisted in a helical manner.

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

[0220]

Embedded image

[0221]

Embedded image

[0222]

Embedded image

The polymerizable group (Q) is an unsaturated polymerizable group (Q1
To Q7), an epoxy group (Q7) or an aziridinyl group (Q8), more preferably an unsaturated polymerizable group, and more preferably an ethylenically unsaturated polymerizable group (Q
1 to Q6) are most preferred. In the above formula, n is an integer of 4 to 12. Specific numbers are determined according to the type of discotic core (D).
The combination of a plurality of L and Q may be different, but is preferably the same.

Two or more discotic liquid crystal molecules may be used in combination. For example, the polymerizable discotic liquid crystal molecules and the non-polymerizable discotic liquid crystal molecules described above can be used in combination. The non-polymerizable discotic liquid crystal molecule is preferably a compound in which the polymerizable group (Q) of the polymerizable discotic liquid crystal molecule is changed to a hydrogen atom or an alkyl group. That is, the non-polymerizable discotic liquid crystal molecule is preferably a compound represented by the following formula. D (-LR) _{n wherein} D is a discotic core; L is a divalent linking group; R is a hydrogen atom or an alkyl group;
Is an integer of 4 to 12. Disc-shaped core of the above formula (D)
Is the same as the above-mentioned example of the polymerizable discotic liquid crystal molecule except that LQ (or QL) is changed to LR (or RL). Examples of the divalent linking group (L) also include
This is the same as the example of the polymerizable discotic liquid crystal molecules described above. The alkyl group for R preferably has 1 to 40 carbon atoms, and more preferably 1 to 30 carbon atoms. A chain alkyl group is more preferable than a cyclic alkyl group, and a straight-chain alkyl group is more preferable than a branched chain alkyl group. R is particularly preferably a hydrogen atom or a linear alkyl group having 1 to 30 carbon atoms.

The liquid crystal layer used for the optical compensatory sheet may be composed of liquid crystal molecules or the following polymerizable initiators and optional additives (eg, plasticizer, monomer, surfactant, cellulose ester, 1,3,5-triazine). (A compound, a chiral agent) is formed on the liquid crystal alignment film by coating. 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), sulfoxide (eg,
Dimethylsulfoxide), heterocyclic compound (eg, pyridine), hydrocarbon (eg, benzene, hexane), alkyl halide (eg, chloroform, dichloromethane), ester (eg, methyl acetate, butyl acetate), ketone (eg, acetone, Methyl ethyl ketone) and ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination. The application of the coating solution can be performed by a known method (eg, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die coating method).

The polymerization reaction of liquid crystalline molecules includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. Photopolymerization reactions are preferred. Examples of the photopolymerization initiator include α-carbonyl compounds (U.S. Pat.
Nos. 1 and 2367670), acyloin ether (described in US Pat. No. 2,448,828),
α-hydrocarbon-substituted aromatic acyloin compounds (U.S. Pat.
No. 722512), polynuclear quinone compounds (described in U.S. Pat. Nos. 3,046,127 and 2,951,758), and a combination of triarylimidazole dimer and p-aminophenyl ketone (U.S. Pat.
No. 67), acridine and phenazine compounds (JP-A-60-105667, U.S. Pat.
9850) and an oxadiazole compound (described in US Pat. No. 4,221,970).
The amount of the photopolymerization initiator used is preferably 0.01 to 20% by weight, more preferably 0.5 to 5% by weight of the solid content of the coating solution. Light irradiation for the polymerization of discotic liquid crystalline molecules preferably uses ultraviolet light. The irradiation energy is 20 mJ / cm ^{2 to} 5
0 J / cm ² , preferably 100 to 800
More preferably, it is mJ / cm ² . Light irradiation may be performed under heating conditions to promote the photopolymerization reaction. The thickness of the liquid crystal layer used for the optical compensation sheet is preferably 0.1 to 20 μm, and 0.5 to 15 μm.
More preferably, it is most preferably 1 to 10 μm.

[Liquid Crystal Display Device] The liquid crystal element can be used in a liquid crystal display device as a liquid crystal cell or an optical compensation sheet depending on the kind of liquid crystal molecules to be substantially vertically aligned.
As described above, as a liquid crystal cell in which rod-like liquid crystal molecules are substantially vertically aligned, VA (Vertically Aligned) is used.
A mode liquid crystal cell is typical. An optical compensation sheet in which discotic liquid crystal molecules are aligned substantially vertically is particularly effective in an STN (Super Twisted Nematic) mode liquid crystal display device using a liquid crystal cell. The liquid crystal display device includes a liquid crystal cell, a pair of polarizing elements disposed on both sides of the liquid crystal cell, and one or two optical compensation sheets disposed between the liquid crystal cell and one or both polarizing elements.

[0228]

[Example 1] Thickness 100 μm, size 270
A 100 mm × 100 mm triacetyl cellulose film (Fujitac, manufactured by Fuji Photo Film Co., Ltd.) was used as a transparent substrate. A coating solution having the following composition was applied on a transparent substrate using a bar coater. 80 ° C
Was dried with warm air for 10 minutes, and the surface was rubbed to form a vertical alignment film.

塗布 Vertical alignment film coating solution────── ────────────────────────────── Modified polyvinyl alcohol (PV39) 1 part by weight N-methylpyrrolidone 4.8 parts by weight Methyl ethyl ketone 19 0.2 parts by weight Glutaraldehyde (crosslinking agent) 0.05 parts by weight Sulfuric acid 0.01 parts by weight ───────────────────────────── ───────

[0230]

Embedded image

A coating solution having the following composition was applied on the vertical alignment film by an extrusion method.

<< Coating Liquid for Optically Anisotropic Layer >> ───────────────────────────────── 100 parts by weight of the following discotic liquid crystalline compound Photopolymerization initiator (IRGACURE 907) 0.2 parts by weight Methyl ethyl ketone 185 parts by weight ───────────────────────────────── ───

[0233]

Embedded image

The coating layer was heated to 130 ° C. to vertically align the discotic liquid crystalline compound. 13 coating layers
While being heated to 0 ° C., ultraviolet rays were irradiated for 4 seconds to polymerize the terminal vinyl group of the discotic liquid crystalline compound and fix the alignment state. Thus, an optical compensation sheet was produced. The in-plane retardation of the optical compensatory sheet was measured using an ellipsometer, and the average inclination angle was determined from the angle dependence to be 80 °. When the optical compensatory sheet was left for 300 hours under the conditions of 90 ° C. and 95% relative humidity, the liquid crystal compound maintained a uniform alignment state.

Example 2 An optical compensatory sheet was prepared and evaluated in the same manner as in Example 1 except that the same amount of glyoxal (crosslinking agent) was used instead of glutaraldehyde (crosslinking agent). The average tilt angle of discotic liquid crystalline molecules is
It was 75 ゜. Optical compensation sheet at 90 ° C, relative humidity 9
After being left under the condition of 5% for 300 hours, the liquid crystal compound maintained a uniform alignment state.

Example 3 An optical compensatory sheet was prepared and evaluated in the same manner as in Example 1, except that malonaldehyde (crosslinking agent) was used in the same amount instead of glutaraldehyde (crosslinking agent). The average tilt angle of the discotic liquid crystalline molecules was 85 °. When the optical compensatory sheet was left for 300 hours under the conditions of 90 ° C. and 95% relative humidity, the liquid crystal compound maintained a uniform alignment state.

[Comparative Example 1] Inorganic vertical alignment film forming material (E
XP-OA004 (manufactured by Nissan Chemical Industries, Ltd.) was diluted with methanol to a solid content of 2% by weight. This was applied on a glass plate with a bar coater so as to have a thickness of 0.4 μm.
After drying at 40 ° for 10 minutes, an alignment film was formed. After rubbing the alignment film, two antiparacels were formed. In one cell, a rod-like liquid crystal molecule (MBBA) was inserted. Into the other cell, a product obtained by evaporating and solidifying methyl ethyl ketone from the coating solution for the optically anisotropic layer used in Example 1 (discotic liquid crystalline molecules) was inserted. For each cell, the alignment state of liquid crystalline molecules was examined. In the cell into which the rod-like liquid crystal molecules were inserted, the rod-like liquid crystal molecules were nematically aligned in a direction perpendicular to the glass plate. On the other hand, in the cell in which the discotic liquid crystal molecules were inserted, the average tilt angle was 30 ° and the vertical alignment (50 to 90)
゜) did not become. The used material for forming an inorganic vertical alignment film is commercially available as a vertical alignment film for rod-like liquid crystalline molecules, and is most commonly used. Experimental results using other commercially available vertical alignment films for rod-like liquid crystal molecules show that the vertical alignment films for commercially available rod-like liquid crystal molecules have insufficient functions to vertically align discotic liquid crystal molecules. did.

Continued on the front page F-term (reference) 2H090 HA03 HB07Y KA05 KA08 KA18 MA01 MB09 4J100 AD02P AE09Q AE09R AF16Q AG04Q AG04R AG04S AG08Q AG08R AG08S AH40Q AH40R AH40S AL74R AL74S AL92R BA04 BA02 BA04 BA02 BA04 BA02 BA04 BA12Q BA15H BA15Q BA15R BA15S BA16R BA17H BA17R BA22H BA22Q BA32H BA32R BA34H BA34Q BA35H BA35R BA38H BA38R BA38S BA40H BA40Q BA51H BA56H BA56R BA64H BA64R BB03H BB03Q BB07H BB07Q BB07R BC04H BC04Q BC43H BC43Q BC43R BC43S BC44H BC44Q BC44R BC44S BC45H BC45Q BC45R BC48H BC48Q BC49H BC49Q BC54H BC54R BC54S BC65H BC65R BC65S BC73H BC73Q CA04 CA05 CA06 CA31 HA43 HA53 HA61 HA62 HC09 HC27 HC29 HC39 HC43 HC64 HC71 HC75 JA39

Claims (6)

[Claims] 1. A liquid crystal alignment film provided on a substrate for aligning liquid crystal, wherein the liquid crystal alignment film contains a modified polyvinyl alcohol, and the modified polyvinyl alcohol has an aromatic ring or an aromatic heterocyclic ring in a side chain. A liquid crystal alignment film comprising 2 to 80 mol% of a repeating unit having 2, 3, or 4 of the above, and crosslinked with modified polyvinyl alcohol. 2. The liquid crystal alignment film according to claim 1, wherein the repeating unit having two, three or four aromatic rings or aromatic heterocycles in the side chain is represented by the following formula (I). Embedded image In the formula, L ¹ is a single bond, -CO-, -CO-NH-,-
Alkylene group-, -CO-NH-alkylene group-, -C
A linking group selected from the group consisting of an O-NH-alkylene group -O-, -CO-NH-alkylene group -CO-O- and -CO-NH-alkylene group -CO-NH-;
L ² , L ³ and L ⁴ are each independently a single bond,-
O-, -CO-, -O-CO-, -CO-O-, -O-
CO-O-, -CO-NH-, -alkylene group-, -O
A linking group selected from the group consisting of -alkylene group- and -alkylene group -O-; Ar ¹ , Ar ² , Ar ³
And Ar ⁴ are each independently an aromatic or heteroaromatic ring; and m and n are 0 or 1
It is. 3. The liquid crystal alignment film according to claim 1, wherein the modified polyvinyl alcohol is crosslinked by a reaction between a hydroxyl group of the modified polyvinyl alcohol and a crosslinking agent. 4. The liquid crystal alignment film according to claim 3, wherein the crosslinking agent is a bifunctional aldehyde. 5. A liquid crystal device in which a substrate, a liquid crystal alignment film and a liquid crystal layer formed of liquid crystal molecules are laminated in this order, wherein the liquid crystal alignment film contains modified polyvinyl alcohol, and the modified polyvinyl alcohol has a side chain. Contains 2 to 80 mol% of repeating units having 2, 3, or 4 aromatic rings or aromatic heterocycles, is modified polyvinyl alcohol crosslinked, and has 50 to 90 liquid crystal molecules.
A liquid crystal element characterized by being oriented at an average inclination angle in a range of degrees. 6. A repeating unit having two, three or four aromatic rings or aromatic heterocyclic rings in the side chain has a number of 2 to 80.
A method in which liquid crystal molecules are aligned at an average tilt angle in the range of 50 to 90 degrees using a liquid crystal alignment film containing a modified polyvinyl alcohol containing mol% and crosslinked.