JP2008176304A - Liquid crystal aligning agent, liquid crystal aligning film, liquid crystal display element and optical member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal aligning agent used for forming a liquid crystal alignment layer to which liquid crystal alignability is imparted by the irradiation with polarized or unpolarized radiation, without conducting a rubbing treatment. <P>SOLUTION: The liquid crystal aligning agent contains a polyamic acid obtained by using, as a diamine component, a diamine such as 3,5-diaminobenzyl=cinnamate or an imidized polymer of the polyamic acid. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, a liquid crystal display element, and an optical member. More specifically, a liquid crystal alignment agent used for forming a liquid crystal alignment film capable of imparting liquid crystal alignment ability by irradiation with polarized radiation without performing a rubbing treatment, such a liquid crystal alignment film, such as The present invention relates to a liquid crystal display element having a liquid crystal alignment film and an optical member.

Conventionally, a nematic liquid crystal having positive dielectric anisotropy is sandwiched with a substrate with a transparent electrode having a liquid crystal alignment film, and the major axis of liquid crystal molecules is continuously twisted between 0 and 360 degrees between the substrates as necessary. A liquid crystal display element having a liquid crystal cell of a TN (Twisted Nematic) type, a STN (Super Twisted Nematic) type, an IPS (In Plane Switching) type, or the like is known (see Patent Document 1).
As a means for aligning the liquid crystal in such a liquid crystal cell, an organic film is formed on the surface of the substrate, and then the surface of the organic film is subjected to rubbing treatment in one direction with a cloth material such as rayon to achieve the liquid crystal alignment ability. There are a method of applying, a method of obliquely depositing silicon oxide on the surface of a substrate, a method of forming a monomolecular film having a long chain alkyl group using the Langmuir-Blodgett method (LB method), and the like. Of these, rubbing is generally used from the viewpoint of substrate size, liquid crystal alignment uniformity, processing time, and processing cost.

However, if the alignment of the liquid crystal is performed by rubbing, dust is likely to be generated in the process or static electricity is likely to be generated, so that dust adheres to the alignment film surface and causes display defects. there were. In particular, in the case of a substrate having a TFT (Thin Film Transistor) element, there has been a problem that the circuit damage of the TFT element occurs due to the generated static electricity, resulting in a decrease in yield. Further, in liquid crystal display elements that will be further refined in the future, unevenness is generated on the substrate surface as the density of pixels increases, so that a uniform rubbing process is further required.
As another means of aligning the liquid crystal in the liquid crystal cell, the liquid crystal is irradiated by irradiating polarized or non-polarized radiation to a photosensitive thin film such as polyvinyl cinnamate or poly (4′-methacryloyloxychalcone) formed on the substrate surface. A photo-alignment technique that imparts alignment ability is known. According to this method, uniform liquid crystal alignment can be realized without generating static electricity or dust (Patent Literature 2, Patent Literature 3, Patent Literature 4, Patent Literature 5, Patent Literature 6, Patent Literature 7, Patent Literature 8). , Patent Document 9, Patent Document 10 and Patent Document 11).

Conventionally, in the display, optoelectronics, and optical fields, optical members such as polarizing plates, phase difference plates, and optically rotatory optical films have been used. These optical members have various uses. For example, in addition to being widely used as a member such as a polarizing plate, a compensation plate, and a viewing angle improving film in a liquid crystal display device, they are also used as a phase difference plate for an optical pickup element in an optical disk device. It has been.
As a method for producing such an optical member, many methods such as a method using a stretched and oriented resin film have been conventionally known. However, the optical member manufactured by such a method has the same optical characteristics over the entire surface, and it has not been possible to obtain an optical member having different optical characteristics in different regions within the surface.

On the other hand, the prior invention (see Patent Document 12 and Patent Document 13) is a method of aligning a liquid crystal substance having an optical function on a liquid crystal alignment film formed on a substrate by a photo-alignment technique and then fixing the alignment state. It is revealed. By this method, it is possible to easily manufacture optical members having different optical characteristics in different regions within the surface.
As described above, the liquid crystal alignment film manufactured by the optical alignment technique can be effectively applied to a liquid crystal display element and an optical member. However, the conventional photo-alignment technique using a photo-crosslinkable material such as polyvinyl cinnamate has a problem that a large amount of radiation is necessary to obtain a stable liquid crystal alignment ability. That is, in such a liquid crystal alignment film, since the anisotropy of the liquid crystal alignment film is maintained by the cross-linked structure generated by radiation irradiation, the liquid crystal alignment ability is unstable when the radiation irradiation amount is not sufficiently large. become.
JP 56-91277 A JP-A-1-120528 JP-A-6-287453 JP-A-10-251646 Japanese Patent Laid-Open No. 11-2815 JP-A-11-152475 JP 2000-144136 A JP 2000-319510 A JP 2000-281724 A JP 2003-307736 A JP 2004-163646 A JP-A-6-289374 JP 2004-20658 A

  The objective of this invention is providing the liquid crystal aligning agent used for formation of the liquid crystal aligning film which can provide liquid crystal aligning ability by polarized or non-polarized radiation irradiation, without performing a rubbing process.

  Another object of the present invention is to provide a liquid crystal alignment film.

  Still another object of the present invention is to provide a liquid crystal display device.

  Still another object of the present invention is to provide an optical member.

  Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are as follows.
The following formulas (I) and (II):

(Here, T ¹ and T ² are each independently a tetravalent organic group, and Z ¹ and Z ² are each independently an organic group represented by the following formula (III) or the following formula (IV ).

Here, D ³ and D ⁴ are each independently an oxygen atom or NR (R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), and S ³ and S ⁴ are independently of each other a carbon number of 0 ˜1 bonding group or single bond, Q ³ is a monovalent aromatic group, Q ⁴ is a divalent aromatic group, X ⁴ is a monovalent organic group, R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. )
And a polymer having at least one unit selected from the group consisting of units represented by each of the above.

According to the present invention, the above objects and advantages of the present invention are secondly,
This is achieved by a method for producing a liquid crystal alignment film, wherein the thin film comprising the liquid crystal alignment agent of the present invention is irradiated with polarized or non-polarized radiation to impart liquid crystal alignment ability.

According to the present invention, the above objects and advantages of the present invention are thirdly,
This is achieved by the liquid crystal alignment film manufactured by the above manufacturing method of the present invention.

According to the present invention, the above objects and advantages of the present invention are fourthly,
The liquid crystal display element having the liquid crystal alignment film of the present invention achieves this.

According to the present invention, the above objects and advantages of the present invention are
This is achieved by an optical member using the liquid crystal alignment film of the present invention.

  When the liquid crystal aligning agent of the present invention is used, a liquid crystal aligning film having high stability of liquid crystal aligning ability can be obtained with a small radiation dose as compared with the case where the liquid crystal aligning film is formed by a conventional photo-alignment method. Therefore, when this liquid crystal alignment film is applied to a liquid crystal display element, a liquid crystal display element having excellent display characteristics can be manufactured at a lower cost than in the past. When the liquid crystal alignment film of the present invention is applied to the production of an optical member, an optical member having excellent in-plane uniformity can be produced at a lower cost than before. Therefore, these liquid crystal display elements and optical members can be effectively applied to various devices, and are suitable for display devices such as desk calculators, watches, table clocks, coefficient display boards, word processors, personal computers, liquid crystal televisions or optical disk devices, for example. Used for.

Liquid crystal aligning agent The liquid crystal aligning agent of the present invention is a polymer having at least one unit selected from the group consisting of units represented by the above formulas (I) and (II) (hereinafter referred to as “specific polymer”). Say).
T ¹ in the above formula (I) and T ² in the above formula (II) are tetravalent organic groups.
Z ¹ in the above formula (I) and Z ² in the above formula (II) are an organic group represented by the above formula (III) or an organic group represented by the above formula (IV) (hereinafter referred to as “photoreaction”). It is also referred to as a “part”), and has a characteristic that when the liquid crystal alignment film is irradiated with polarized or non-polarized radiation, it undergoes photoreaction in an azimuth-selective manner and exhibits liquid crystal alignment ability. In the specific polymer used in the present invention, since the photoreactive site is firmly bonded to the polyamic acid or the rigid polyimide main chain, the alignment stability of the structure generated by the photoreaction is high. As a result of this, the liquid crystal alignment film of the present invention exhibits stable liquid crystal alignment even with a small radiation dose.

D ³ in the above formula (III) and D ⁴ in the above formula (IV) are each independently an oxygen atom or NR (R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), preferably an oxygen atom and NH, more preferably an oxygen atom.
S ³ in the above formula (III) and S ⁴ in the above formula (IV) are each independently a linking group having 0 to 1 carbon atoms or a single bond. Preferred examples of the linking group represented by S ³ include a methylene group. The bonding group represented by S ⁴ is preferably a methylene group, a carbonyl group, an ester bond, a urethane bond, a urea bond, a carbonate bond, an ether bond, a group represented by —CH ₂ O—, —OCH ₂ - group represented by and, -SO ₂ -, a group represented by may be mentioned. Of these, S ³ and S ⁴ are preferably a single bond and a methylene group.
Q ³ in the above formula (III) is a monovalent aromatic group. More specifically, a monovalent aromatic group having 6 to 12 carbon atoms such as a phenyl group, a biphenylyl group, and a naphthyl group, and one or two or more hydrogen atoms in these groups are a halogen atom, a carbon atom, Examples thereof include an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, a haloalkoxyl group having 1 to 6 carbon atoms, and a group substituted with a cyano group. Preferred examples of these monovalent aromatic groups include phenyl group, 4-methoxyphenyl group, 4-pentylphenyl group, 4-fluorophenyl group, 3-methoxyphenyl group, 3-pentylphenyl group, and 3-fluoro. Phenyl group, 3,4-difluorophenyl group, 3,4,5-trifluorophenyl group, 4-trifluoromethylphenyl group, 3-trifluoromethylphenyl group, biphenyl group, 4-fluorobiphenyl group, 3,4 -Difluorobiphenyl group, 3,4,5-trifluorobiphenyl group, 1-naphthyl group, 4-methoxy-1-naphthyl group, 2-naphthyl group and 6-methoxy-2-naphthyl group can be mentioned.

Q ⁴ in the above formula (IV) is a divalent aromatic group. More specifically, a divalent aromatic group having 6 to 12 carbon atoms such as a phenylene group, a biphenylene group, and a naphthylene group, and one or more hydrogen atoms in these groups are a halogen atom, a carbon atom, Examples include a group substituted with an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, a haloalkoxyl group having 1 to 6 carbon atoms, or a cyano group. it can. Preferred examples of these divalent aromatic groups include 1,2-phenylene group, 3-fluoro-1,2-phenylene group, 4-fluoro-1,2-phenylene group, and 3-methoxy-1,2 -Phenylene group, 4-methoxy-1,2-phenylene group, 3-methyl-1,2-phenylene group, 4-methyl-1,2-phenylene group, 1,3-phenylene group, 2-fluoro-1, 3-phenylene group, 4-fluoro-1,3-phenylene group, 5-fluoro-1,3-phenylene group, 2-methoxy-1,3-phenylene group, 4-methoxy-1,3-phenylene group, 5 -Methoxy-1,3-phenylene group, 2-methyl-1,3-phenylene group, 4-methyl-1,3-phenylene group, 5-methyl-1,3-phenylene group, 1,4-phenylene group, 2-Fluoro-1,4 Phenylene group, 2-methoxy-1,4-phenylene group, 2-methyl-1,4-phenylene group, 4,4′-biphenylene group, 3,4′-biphenylene group, 3,3′-biphenylene group, 1 , 4-naphthylene group and 2,6-naphthylene group.
X ⁴ in the above formula (IV) is a monovalent organic group, preferably a C 1-11 monovalent organic group which may be substituted with a substituent. Examples of the organic group include an alkyl group having 1 to 11 carbon atoms, a haloalkyl group having 1 to 11 carbon atoms, and a phenyl group which may be appropriately substituted with a substituent.
In the above formulas (III) and (IV), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, preferably a hydrogen atom or methyl A group, more preferably a hydrogen atom.

Specific Polymer The specific polymer contained in the liquid crystal aligning agent of the present invention has a polyamic acid and an imidized polymer having at least one unit selected from the units represented by the formulas (I) and (II). It is a coalescence. The polyamic acid which is a specific polymer includes tetracarboxylic dianhydride and the following formula (V)

In the formula, Z ⁵ is an organic group represented by the above formula (III) or an organic group represented by the above formula (IV).
It is obtained by reacting with a diamine compound represented by Moreover, the imidized polymer which is a specific polymer is obtained by dehydrating and ring-closing the polyamic acid.

Specific examples of the diamine compound represented by the above formula (V) used for the synthesis of the diamine compound specific polymer include 3,5-diaminobenzyl cinnamate and 3,5-diaminobenzyl 4-methoxycinna. Mate, 3,5-diaminobenzyl = 4-pentylcinnamate, 3,5-diaminobenzyl = 4-fluorocinnamate, 3,5-diaminobenzyl = 4-trifluoromethylcinnamate, 3,5-diaminobenzyl = 3-methoxycinnamate, 3,5-diaminobenzyl = 3-pentylcinnamate, 3,5-diaminobenzyl = 3-fluorocinnamate, 3,5-diaminobenzyl = 3-trifluoromethylcinnamate, 3,5 -Diaminobenzyl = 3,4-difluorocinnamate, 3,5-diaminobenzyl = 3, , 5-trifluorocinnamate, 2,4-diaminobenzyl = cinnamate, 2,4-diaminobenzyl = 4-methoxycinnamate, 2,4-diaminobenzyl = 4-pentylcinnamate, 2,4-diaminobenzyl = 4-fluorocinnamate, 2,4-diaminobenzyl = 4-trifluoromethylcinnamate, 2,4-diaminobenzyl = 3-methoxycinnamate, 2,4-diaminobenzyl = 3-pentylcinnamate, 2,4 -Diaminobenzyl = 3-fluorocinnamate, 2,4-diaminobenzyl = 3-trifluoromethylcinnamate, 2,4-diaminobenzyl = 3,4-difluorocinnamate, 2,4-diaminobenzyl = 3,4 , 5-trifluorocinnamate, 2,4-diaminophenyl cinnamate 2,4-diaminophenyl = 4-methoxycinnamate, 2,4-diaminophenyl = 4-pentylcinnamate, 2,4-diaminophenyl = 4-fluorocinnamate, 2,4-diaminophenyl = 4- Trifluoromethylcinnamate, 2,4-diaminophenyl = 3-methoxycinnamate, 2,4-diaminophenyl = 3-pentylcinnamate, 2,4-diaminophenyl = 3-fluorocinnamate, 2,4-diamino Phenyl = 3-trifluoromethyl cinnamate, 2,4-diaminophenyl = 3,4-difluorocinnamate, 2,4-diaminophenyl = 3,4,5-trifluorocinnamate, methyl = 4 ′-(3 , 5-Diaminobenzoyloxy) cinnamate, ethyl = 4 ′-(3,5-diaminobenzoyl) Xy) cinnamate, pentyl = 4 ′-(3,5-diaminobenzoyloxy) cinnamate, phenyl = 4 ′-(3,5-diaminobenzoyloxy) cinnamate, methyl = 4 ′-(3,5-diaminobenzyloxy) Cinnamate, ethyl = 4 ′-(3,5-diaminobenzyloxy) cinnamate, pentyl = 4 ′-(3,5-diaminobenzyloxy) cinnamate, phenyl = 4 ′-(3,5-diaminobenzyloxy) cinnamate, Methyl = 4 ′-(2,4-diaminobenzyloxy) cinnamate, ethyl = 4 ′-(2,4-diaminobenzyloxy) cinnamate, pentyl = 4 ′-(2,4-diaminobenzyloxy) cinnamate, phenyl = 4 ′-(2,4-diaminobenzyloxy) cinnamate, methyl = 4 ′-(2,4- Diaminophenoxy) cinnamate, ethyl = 4 ′-(2,4-diaminophenoxy) cinnamate, pentyl = 4 ′-(2,4-diaminophenoxy) cinnamate and phenyl = 4 ′-(2,4-diaminophenoxy) cinnamate Can be mentioned. Among these, 3,5-diaminobenzyl cinnamate, 3,5-diaminobenzyl 4-methoxycinnamate, 3,5-diaminobenzyl 4-trifluoromethyl cinnamate, 2,4-diaminobenzyl cinnamate, 2,4-diaminobenzyl = 4-methoxycinnamate, 2,4-diaminobenzyl = 4-trifluoromethylcinnamate, methyl = 4 ′-(2,4-diaminobenzyloxy) cinnamate, ethyl = 4 ′-( 2,4-diaminobenzyloxy) cinnamate and pentyl = 4 ′-(2,4-diaminobenzyloxy) cinnamate are preferred. These diamine compounds can be used alone or in combination of two or more.

These diamine compounds can be synthesized, for example, by the method described in International Publication WO99 / 51662.
In the synthesis of the polyamic acid which is a specific polymer, in order to improve its properties and to give functions such as pretilt angle expression or vertical alignment, other than the diamine compound represented by the above formula (V), These diamine compounds can be used in combination.

  Examples of such other diamine compounds include compounds exemplified as “other diamine compounds” and “diamine compounds having a specific hydrophobic group” in paragraphs [0044] to [0046] of JP-A No. 2004-163646. The descriptions in paragraphs [0044] to [0046] of JP-A-2004-163646 are incorporated herein. Of these, preferred are p-phenylenediamine, 4,4′-diaminodiphenylmethane, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 4,4′- (P-phenyleneisopropylidene) bisaniline, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2′-bis [4- (4-Amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4 -Amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl, 1-hexadecylo Cis-2,4-diaminobenzene, 1-octadecyloxy-2,4-diaminobenzene, 1-cholesteryloxy-2,4-diaminobenzene, 1-cholestanyloxy-2,4-diaminobenzene, hexadecyloxy ( 3,5-diaminobenzoyl), octadecyloxy (3,5-diaminobenzoyl), cholesteryloxy (3,5-diaminobenzoyl), and cholestanyloxy (3,5-diaminobenzoyl), and the following formula (1) ) And (2). These other diamine compounds can be used alone or in combination of two or more.

  Such other diamine compounds are preferably used in an amount of less than 50 mol% of the total diamine compounds.

Examples of the tetracarboxylic dianhydride used in the synthesis of the tetracarboxylic anhydride specific polymer include, for example, “other tetracarboxylic dianhydrides” in paragraphs [0039] to [0042] of JP-A-2004-163646, and The compound illustrated as "the tetracarboxylic dianhydride which has a specific hydrophobic group" can be mentioned. The descriptions in paragraphs [0039] to [0042] of Japanese Patent Application Laid-Open No. 2004-163646 are combined in this specification. Of these, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan is preferable. 1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -8-methyl-naphtho [1,2-c]- Furan-1,3-dione, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, butanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride 1,2,3,4-cyclobutanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5 8-Naphthalenetetraca Boronic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, and the following formulas (3) to (6) The compound represented by each of these can be mentioned. These tetracarboxylic dianhydrides can be used alone or in combination of two or more.

Specific polymer The ratio of tetracarboxylic dianhydride and diamine compound used for the synthesis reaction of polyamic acid, which is a specific polymer, is tetracarboxylic dianhydride with respect to 1 equivalent of amino group contained in the diamine compound. The ratio in which the acid anhydride group is 0.5 to 2 equivalents is preferable, and the ratio is more preferably 0.7 to 1.2 equivalents.
The synthetic reaction of polyamic acid is preferably carried out in an organic solvent under a temperature condition of -20 to 150 ° C, more preferably 0 to 100 ° C. Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized polyamic acid. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, N, Aprotic polar solvents such as N-dimethylimidazolidinone, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide; and phenolic solvents such as m-cresol, xylenol, phenol, halogenated phenol Can do. The amount of organic solvent used (a) is preferably such that the total amount (b) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight based on the total amount (a + b) of the reaction solution. It is preferable that the amount is small.

  The organic solvent can be used in combination with an alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbon, or the like, which is a poor solvent for polyamic acid, as long as the polyamic acid to be produced does not precipitate. Specific examples of the poor solvent include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, Acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene Glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n- Chill ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1 , 4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, isoamylpropionate, isoamylisobutyrate, diisopentyl ether and the like.

  As described above, a reaction solution obtained by dissolving polyamic acid is obtained. The reaction solution is poured into a large amount of poor solvent to obtain a precipitate, and the precipitate is dried under reduced pressure to obtain a polyamic acid. Then, the reaction solution is poured into a large amount of poor solvent to obtain a precipitate, and the precipitate is dried under reduced pressure, or the reaction solution is distilled off under reduced pressure with an evaporator to obtain a polyamic acid. Further, the polyamic acid can be purified by dissolving the polyamic acid again in an organic solvent and then precipitating it with a poor solvent, or performing the step of evaporating under reduced pressure with an evaporator once or several times.

The imidized polymer used in the present invention can be prepared by dehydrating and ring-closing the polyamic acid. The polyamic acid is dehydrated and closed by (i) a method of heating the polyamic acid, or (ii) dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to this solution, and heating as necessary. By the method.
The reaction temperature in the method of heating the polyamic acid (i) is preferably 50 to 200 ° C, more preferably 60 to 170 ° C. When the reaction temperature is less than 50 ° C., the dehydration ring-closing reaction does not proceed sufficiently, and when the reaction temperature exceeds 200 ° C., the molecular weights of the imidized polymer and unreacted polyamic acid may be lowered.

  On the other hand, in the method (ii) of adding a dehydrating agent and a dehydrating ring-closing catalyst to the polyamic acid solution, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride is used as the dehydrating agent. Can do. The amount of the dehydrating agent used is preferably 0.01 to 20 mol with respect to 1 mol of the polyamic acid repeating unit. Moreover, as a dehydration ring closure catalyst, tertiary amines, such as a pyridine, a collidine, a lutidine, a triethylamine, can be used, for example. However, it is not limited to these. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. In addition, as an organic solvent used for dehydration ring closure reaction, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. And the reaction temperature of dehydration ring closure reaction becomes like this. Preferably it is 0-180 degreeC, More preferably, it is 10-150 degreeC. In addition, the imidized polymer can be purified by performing the same operation as the polyamic acid purification method on the reaction solution thus obtained.

  The imidized polymer may be partially dehydrated and closed and have a low imidization rate. The imidation ratio in the imidized polymer used in the present invention is preferably 40% or more, more preferably 80% or more. Here, the “imidation rate” is the percentage of the number of repeating units that form an imide ring with respect to the total number of repeating units in the polymer. At this time, a part of the imide ring may be an isoimide ring. The imidization rate can be determined by the following method.

Method for measuring imidation rate of imidized polymer After imidized polymer was dried under reduced pressure at room temperature, it was dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance. It can be obtained from the equation shown in (i).
Imidation ratio (%) = (1-A ¹ / A ² × α) × 100 ------ (i)
A ¹ : NH group proton-derived peak area (10 ppm)
A ² : Peak area derived from other protons α: Number ratio of other protons to one proton of NH group in polymer precursor (polyamic acid)

Terminal-modified polymer The polyamic acid and imidized polymer may be of a terminal-modified type whose molecular weight is adjusted. Such a terminal-modified type can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when synthesizing the polyamic acid. Here, as the acid monoanhydride, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride , N-hexadecyl succinic anhydride and the like. Examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, and n-undecyl. Amine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, etc. be able to. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

The solution viscosity specific polymer preferably has a viscosity of 20 to 800 mPa · s, more preferably 30 to 500 mPa · s, when a 10% by weight solution is obtained.
In addition, the solution viscosity (mPa * s) of the polymer was measured at 25 degreeC using the E-type rotational viscometer about the solution diluted to the solid content concentration of 10 weight% using the predetermined | prescribed solvent.

Liquid crystal aligning agent The liquid crystal aligning agent of this invention consists of a solution containing a specific polymer. The solvent used at this time is not particularly limited as long as it is an organic solvent capable of dissolving the polymer. As such a solvent, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned, for example. These can be used alone or in combination of two or more. Moreover, the poor solvent illustrated as what is used for the synthesis | combination of a polyamic acid can also be used together. A preferred solvent composition is a composition obtained by combining the above-mentioned solvents, in which a polymer does not precipitate in the aligning agent, and the surface tension of the aligning agent is in the range of 25 to 40 mN / m. is there.
The solid content concentration in the liquid crystal aligning agent of the present invention is selected in consideration of viscosity, volatility and the like. Preferably it is the range of 1-10 weight%. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface to form a coating film that becomes a liquid crystal alignment film. When the solid content concentration is less than 1% by weight, the film thickness of this coating film is too small. It is difficult to obtain a good liquid crystal alignment film. When the solid content concentration exceeds 10% by weight, it is difficult to obtain a good liquid crystal alignment film because the film thickness is excessive, and the viscosity of the liquid crystal aligning agent is increased, so that the coating properties tend to be inferior.

The particularly preferable solid content concentration range varies depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, when the spinner method is used, the range of 1.5 to 4.5% by weight is particularly preferable. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the ink jet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s.
Moreover, the temperature at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 0 to 200 degreeC, More preferably, it is 20 to 60 degreeC.

Other Additives The liquid crystal aligning agent of the present invention can contain other polymers in addition to the specific polymer in order to improve solution properties and electrical properties. Examples of such other polymers include polyamic acids other than specific polymers, polyimides, polyamic acid esters, polyesters, polyamides, polysiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly (styrene-phenylmaleimide) derivatives, poly ( And (meth) acrylate. Of these, polyamic acid is preferable from the viewpoint of heat resistance and electrical characteristics. Moreover, 1-100 weight% is preferable, as for the ratio of the specific polymer with respect to all the polymers contained in a liquid crystal aligning agent, 10-90 weight% is more preferable, and 10-70 weight% is especially preferable.

Moreover, the liquid crystal aligning agent of this invention can also contain various thermosetting crosslinking agents for stabilization of a pretilt angle and a coating-film intensity | strength improvement. As the thermosetting crosslinking agent, a polyfunctional epoxy-containing compound is effective, and bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, cyclic aliphatic epoxy resin, glycidyl ester type epoxy resin, glycidyl diamine. Epoxy resins, heterocyclic epoxy resins, epoxy group-containing acrylic resins, and the like can be used. Examples of commercially available products include Epolite 400E and 3002 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.), Epicoat 828 and 152, and Epoxy Novolak 180S (manufactured by Yuka Shell Epoxy Co., Ltd.). The blending ratio of these polyfunctional epoxy-containing compounds is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the specific polymer.
Furthermore, when using the above-mentioned polyfunctional epoxy-containing compound, a base catalyst such as 1-benzyl-2-methylimidazole can be added for the purpose of efficiently causing a crosslinking reaction.

  Moreover, the liquid crystal aligning agent of this invention can contain a functional silane containing compound for the purpose of improving adhesiveness with a board | substrate. Examples of the functional silane-containing compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl). -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-amino Propyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1, , 7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N -Benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (Oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, and tetracarboxylic dianhydride and amino group-containing silane described in JP-A-63-291922 A reaction product with a compound can be exemplified. The blending ratio of these functional silane-containing compounds is preferably 2 parts by weight or less, more preferably 0.2 parts by weight or less with respect to 100 parts by weight of the specific polymer.

Liquid crystal alignment film As a method of forming a liquid crystal alignment film using the liquid crystal aligning agent of this invention, the following method is mentioned, for example. First, the liquid crystal aligning agent of the present invention is applied to the transparent conductive film side of the substrate provided with the transparent conductive film by, for example, a roll coater method, a spinner method, a printing method, an ink jet method or the like, and then heated to form a coating film. To form.
As the substrate, for example, a glass such as float glass or soda glass, a transparent substrate made of a plastic film such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or alicyclic polyolefin can be used.
As the transparent conductive film, a NESA film made of SnO ₂ , an ITO film made of In ₂ O ₃ —SnO _2, or the like can be used. For patterning these transparent conductive films, a photo-etching method, a method using a mask in advance, or the like is used.

  When applying the liquid crystal aligning agent, a functional silane-containing compound or titanate may be applied in advance on the substrate and the transparent conductive film in order to further improve the adhesion between the substrate and the transparent conductive film and the coating film. it can. After applying the liquid crystal aligning agent, preheating (pre-baking) is preferably performed for the purpose of preventing dripping of the applied aligning agent. The pre-baking temperature is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 40 to 100 ° C. Thereafter, a baking (post-baking) step is performed for the purpose of completely removing the solvent and heat imidizing the polyamic acid. The firing (post-bake) temperature is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. In this way, the liquid crystal aligning agent of the present invention containing a polyamic acid forms a coating film that becomes a liquid crystal aligning film by removing the organic solvent after coating, and further proceeds with dehydration ring closure by further heating. An imidized liquid crystal alignment film can also be used. The film thickness of the liquid crystal alignment film to be formed is preferably 0.001 to 1 μm, and more preferably 0.005 to 0.5 μm.

Next, the coating film is irradiated with linearly polarized light or partially polarized radiation, or non- (non) polarized radiation, and in some cases, a heat treatment is further performed at a temperature of 150 to 250 ° C. to impart liquid crystal alignment ability. . As the radiation, ultraviolet rays and visible rays having a wavelength of 150 nm to 800 nm can be used. Ultraviolet light having a wavelength of 300 nm to 400 nm is preferred. When the used radiation is linearly polarized or partially polarized, irradiation may be performed from a direction perpendicular to the substrate surface, or from an oblique direction to give a pretilt angle, or a combination of these. You may go. When irradiating non-polarized radiation, the direction of irradiation needs to be an oblique direction.
Examples of the light source that can be used include a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, a semiconductor laser, and a light emitting diode. Further, the ultraviolet rays in the preferable wavelength region can be obtained by means of using a filter, a diffraction grating or the like together with the light source.
The “pretilt angle” in the present invention represents an angle of inclination of liquid crystal molecules from a direction parallel to the substrate surface.

Liquid crystal display element The liquid crystal display element formed using the liquid crystal aligning agent of this invention is manufactured as follows. A substrate on which the liquid crystal alignment film is formed is prepared, two of them are opposed so that the polarization direction of the linearly polarized radiation irradiated on the liquid crystal alignment film is a predetermined angle, and a peripheral portion between the substrates is sealed with a sealant. A liquid crystal cell is formed by sealing, filling liquid crystal, and sealing the filling hole. Next, it is desirable that the liquid crystal cell is heated to a temperature at which the liquid crystal used has an isotropic phase and then cooled to room temperature to remove the flow alignment during injection.
Then, the polarizing plates are bonded to both surfaces so that the polarization directions of the polarizing plates form a predetermined angle with the alignment axis of the liquid crystal alignment film of the substrate, thereby obtaining a liquid crystal display element. A TN type or STN type liquid crystal cell is provided by adjusting the angle formed by the polarization direction of the irradiated linearly polarized radiation and the angle between each substrate and the polarizing plate in the two substrates on which the liquid crystal alignment film is formed. A liquid crystal display element can be obtained arbitrarily.
As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.

As the liquid crystal, for example, a nematic liquid crystal, a smectic liquid crystal, or the like can be used. In the case of the TN liquid crystal cell and the STN liquid crystal cell, those having positive dielectric anisotropy for forming a nematic liquid crystal are preferable. For example, biphenyl liquid crystal, phenylcyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl A cyclohexane liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, a bicyclooctane liquid crystal, a cubane liquid crystal, or the like is used. Further, for example, a cholesteric liquid crystal such as cholestyl chloride, cholesteryl nonate, cholesteryl carbonate or a chiral agent such as that sold under the trade name C-15, CB-15 (manufactured by Merck) is added to the liquid crystal. It can also be used. Furthermore, a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate can also be used. In the case of a vertical alignment type liquid crystal cell, those having a negative dielectric anisotropy for forming a nematic type liquid crystal are preferable. Phenylcyclohexane-based liquid crystal or the like is used.
The polarizing plate used outside the liquid crystal cell is a polarizing plate composed of a polarizing film called an H film that absorbs iodine while stretching and aligning polyvinyl alcohol, and a cellulose acetate protective film, or a polarizing film composed of the H film itself. A board etc. can be mentioned.

Optical Member The optical member of the present invention can be produced by various methods described in, for example, Japanese Patent Application Laid-Open No. 2004-20658. Among them, a particularly preferable method is a method in which a polymerizable liquid crystal material is applied on the liquid crystal alignment film of the present invention, aligned, and then solidified by polymerization by irradiation with radiation.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[Method for measuring imidization rate of imidized polymer]
The imidized polymer was dried under reduced pressure at room temperature, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance, and determined by the formula shown by the following formula (i). .
Imidation ratio (%) = (1-A ¹ / A ² × α) × 100 ------ (i)
A ¹ : NH group proton-derived peak area (10 ppm)
A ² : Peak area derived from other protons α: Number ratio of other protons to one proton of NH group in polymer precursor (polyamic acid)

[Solution viscosity]
The solution viscosity (mPa · s) of the polymer was measured at 25 ° C. using an E-type rotational viscometer for a solution diluted to a solid concentration of 10% using a predetermined solvent.

Synthesis example 1
Polymerization of polyamic acid 0.1 mol (22 g) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride and 0.1 mol (27 g) of 3,5-diaminobenzyl cinnamate were added to 300 g of N-methyl-2-pyrrolidone. It was dissolved and reacted at 60 ° C. for 6 hours to obtain about 340 g of a polyamic acid solution (hereinafter referred to as “polymer 1a”) having a solid content concentration of 10% by weight and a solution viscosity of 50 mPa · s.

Imidation reaction To 175 g of the polymer 1a, 210 g of N-methyl-2-pyrrolidone, 7.9 g of pyridine and 10.2 g of acetic anhydride were added, followed by dehydration and ring closure at 120 ° C. for 4 hours. After the imidization reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone (pyridine and acetic anhydride used for the imidization reaction were removed from the system in this operation), and the solid content concentration was about An imidized polymer solution (hereinafter referred to as “polymer 1b”) having a solution viscosity of about 55 mPa · s and an imidization ratio of about 50% at a solid content concentration of 10% by weight (N-methyl-2-pyrrolidone solution). ) About 220 g was obtained.

Synthesis example 2
Polymerization of polyamic acid In the same manner as in Synthesis Example 1, except that 0.1 mol (25 g) of 2,4-diaminophenyl cinnamate was used instead of 0.1 mol (27 g) of 3,5-diaminobenzyl cinnamate. Thus, about 340 g of a polyamic acid solution (hereinafter referred to as “polymer 2a”) having a solution viscosity of 45 mPa · s at a solid content concentration of 10% by weight was obtained.

In the same manner as in Synthesis Example 1 except that 175 g of the polymer 1a was used instead of the 175 g of the polymer 1a, the solid content concentration was about 10 wt% and the solid content concentration was 10 wt% (N-methyl- 2-pyrrolidone solution), about 210 g of an imidized polymer solution (hereinafter referred to as “polymer 2b”) having a solution viscosity of about 50 mPa · s and an imidization ratio of about 47% was obtained.

Synthesis example 3
Polymerization of polyamic acid In place of 0.1 mol (27 g) of 3,5-diaminobenzyl cinnamate, 0.1 mol (31 g) of methyl = 4 ′-(3,5-diaminobenzoyloxy) cinnamate was used. In the same manner as in Synthesis Example 1, about 350 g of a polyamic acid solution (hereinafter referred to as “polymer 3a”) having a solution viscosity of 37 mPa · s at a solid content concentration of 10% by weight was obtained.

In the same manner as in Synthesis Example 1 except that 175 g of polymer 3a was used instead of 175 g of polymer 1a, the solid content concentration was about 10 wt% and the solid content concentration was 10 wt% (N-methyl- About 240 g of an imidized polymer solution (hereinafter referred to as “polymer 3b”) having a solution viscosity of 2-pyrrolidone solution) of about 45 mPa · s and an imidization ratio of about 43% was obtained.

Comparative Synthesis Example 1
Polymerization of polyamic acid 0.1 mol (22 g) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride and 0.1 mol (11 g) of p-phenylenediamine were dissolved in 300 g of N-methyl-2-pyrrolidone. The mixture was reacted at 0 ° C. for 6 hours to obtain about 330 g of a polyamic acid solution (hereinafter referred to as “polymer Aa”) having a solid concentration of 10% by weight and a solution viscosity of 78 mPa · s.

Imidization reaction To 200 g of the polymer Aa, 90 g of N-methyl-2-pyrrolidone, 9.5 g of pyridine and 12.3 g of acetic anhydride were added, followed by dehydration and ring closure at 120 ° C. for 4 hours. After the imidization reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone (pyridine and acetic anhydride used for the imidization reaction were removed from the system in this operation), and the solid content concentration was about An imidized polymer solution (hereinafter referred to as “polymer Ab”) having a solution viscosity of about 85 mPa · s and an imidization ratio of about 50% at a solid content concentration of 10% by weight (N-methyl-2-pyrrolidone solution). ) About 150 g was obtained.

Reference example 1
The polymer Ab obtained in Comparative Synthesis Example 1 was diluted with a mixed solvent having a ratio of γ-butyrolactone / butyl cellosolve (1/1) to obtain a solution having a solid content concentration of 2.5% by weight. This solution was a filter having a pore size of 1 μm. To prepare a liquid crystal aligning agent (hereinafter referred to as “liquid crystal aligning agent P”). This solution was applied onto the transparent electrode surface of the glass substrate with a transparent electrode made of an ITO film using a spinner so that the film thickness became 0.1 μm, and dried at 180 ° C. for 1 hour to form a thin film. The thin film was rubbed at a rotational speed of 500 rpm and a stage moving speed of 1 cm / sec using a rubbing machine having a roll around which a nylon cloth was wound. Next, for the pair of substrates subjected to the rubbing treatment, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is screen-printed on the surface on which the liquid crystal alignment film is formed, and then the rubbing directions are orthogonal to each other. The adhesive was heat-cured at 150 ° C. over 1 hour. Next, a nematic liquid crystal (MLC-6221 manufactured by Merck & Co., Inc.) was filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Furthermore, in order to remove the flow alignment at the time of liquid crystal injection, after heating this at 150 ° C. and then slowly cooling it to room temperature, the polarizing direction of the polarizing plate coincides with the rubbing direction of the liquid crystal alignment film of each substrate. Further, when the liquid crystal display element was produced by pasting it on both outer sides of the substrate, the orientation of the liquid crystal was good. When a voltage of 5 V was applied, a change in brightness of the liquid crystal display element was observed in response to ON / OFF of the applied voltage.

Reference example 2
In the same manner as in Reference Example 1, the liquid crystal aligning agent P was applied onto a glass substrate using a spinner so that the film thickness was 0.1 μm, and dried at 180 ° C. for 1 hour to form a thin film. The thin film was rubbed at a rotational speed of 500 rpm and a stage moving speed of 1 cm / sec using a rubbing machine having a roll around which a nylon cloth was wound.
4- (4-n-butylcyclohexyl) cyclohexyl acrylate 50 parts by weight, 4- (4-n-propylcyclohexyl) phenyl acrylate 50 parts by weight, photopolymerization initiator IRGACURE907 (registered trademark) (manufactured by Ciba Specialty Chemicals) 1 part by weight of (2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one) and 100 parts by weight of propylene glycol monomethyl ether acetate as a solvent are mixed to prepare a polymerizable liquid crystal. Prepared.
This polymerizable liquid crystal was applied and aligned on the rubbing-treated alignment film using a spinner. Next, in order to polymerize and solidify the applied polymerizable liquid crystal, ultraviolet rays were irradiated for 1 minute at 100 mW / cm ² using a high-pressure mercury lamp in a nitrogen atmosphere. The solvent in the polymerizable liquid crystal was volatilized and removed by raising the temperature by ultraviolet irradiation.
In this way, a retardation plate that was colorless and transparent and had a uniform slow axis orientation and retardation within the surface was obtained.

Example 1
A liquid crystal aligning agent (hereinafter referred to as “liquid crystal aligning agent 1a”) was prepared in the same manner as in Reference Example 1 except that the polymer 1a obtained in Synthesis Example 1 was used in place of the polymer Ab. Using this liquid crystal aligning agent, a thin film was formed on the substrate in the same manner as in Reference Example 1, and the surface of this thin film was subjected to linearly polarized ultraviolet ray 50 mJ / cm ² using an ultraviolet polarized exposure apparatus LPU-2000S manufactured by Lan Technical Service. (313 nm) was irradiated. Next, a liquid crystal display device was produced in the same manner as in Reference Example 1 except that the direction in which the liquid crystal alignment films were superposed was in accordance with the ultraviolet polarization direction instead of the rubbing direction. It was. When a voltage was applied under the same conditions as in Reference Example 1, a change in light and darkness of the liquid crystal display element was observed in response to ON-OFF of the applied voltage.

Examples 2-3
In the same manner as in Reference Example 1 except that the polymers 2a to 3a obtained in Synthesis Examples 2 to 3 were used in place of the polymer Ab, a liquid crystal aligning agent (hereinafter referred to as “liquid crystal aligning agents 2a to 3a”, respectively). Prepared).
When the liquid crystal display element was produced like Example 1 except having used liquid crystal aligning agent 2a-3a instead of liquid crystal aligning agent 1a, the orientation of the liquid crystal was favorable. When a voltage was applied under the same conditions as in Reference Example 1, a change in light and darkness of the liquid crystal display element was observed in response to ON-OFF of the applied voltage.

Examples 4-6
In the same manner as in Reference Example 1 except that the polymers 1b to 3b obtained in Synthesis Examples 1 to 3 were used in place of the polymer Ab, a liquid crystal aligning agent (hereinafter referred to as “liquid crystal aligning agents 1b to 3b”, respectively). Prepared).
When the liquid crystal display element was produced like Example 1 except having used liquid crystal aligning agent 1b-3b instead of liquid crystal aligning agent 1a, the orientation of the liquid crystal was favorable. When a voltage was applied under the same conditions as in Reference Example 1, a change in brightness of the liquid crystal display element was observed in response to ON-OFF of the applied voltage.

Example 7
Using the liquid crystal aligning agent 1a, a thin film was formed on the substrate in the same manner as in Reference Example 2, and the surface of this thin film was subjected to linearly polarized ultraviolet light 50 mJ / cm ² using an ultraviolet polarized exposure apparatus LPU-2000S manufactured by Lan Technical Service. (313 nm) was irradiated. Next, in the same manner as in Reference Example 2, a polymerizable liquid crystal was applied, and further polymerized and solidified to prepare a retardation plate.
In this way, a retardation plate that was colorless and transparent and had a uniform slow axis orientation and retardation within the surface was obtained.

Examples 8-9
A phase difference plate was prepared in the same manner as in Example 7 except that the liquid crystal aligning agents 2a to 3a were used instead of the liquid crystal aligning agent 1a.
In this way, a retardation plate that was colorless and transparent and had a uniform slow axis orientation and retardation within the surface was obtained.

Examples 10-12
A retardation film was prepared in the same manner as in Example 7 except that the liquid crystal aligning agents 1b to 3b were used in place of the liquid crystal aligning agent 1a.
In this way, a retardation plate that was colorless and transparent and had a uniform slow axis orientation and retardation within the surface was obtained.

Comparative Example 1
A liquid crystal display device was produced in the same manner as in Example 1 except that the liquid crystal aligning agent P was used, and no liquid crystal alignment was observed.

Comparative Example 2
A retardation plate was produced in the same manner as in Example 2 except that the liquid crystal aligning agent P was used. The obtained retardation plate was cloudy and had no retardation.

Claims (5)

The following formulas (I) and (II):

(Here, T ¹ and T ² are each independently a tetravalent organic group, and Z ¹ and Z ² are each independently an organic group represented by the following formula (III) or the following formula (IV ).

In the formula, D ³ and D ⁴ are each independently an oxygen atom or NR (R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), and S ³ and S ⁴ are independently of each other a carbon number of 0 ˜1 bonding group or single bond, Q ³ is a monovalent aromatic group, Q ⁴ is a divalent aromatic group, X ⁴ is a monovalent organic group, R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. )
A liquid crystal aligning agent comprising a polymer having at least one unit selected from the group consisting of units represented by each of:   A method for producing a liquid crystal alignment film, comprising applying a liquid crystal alignment ability to a thin film comprising the liquid crystal alignment agent according to claim 1 by irradiating polarized or non-polarized radiation.   A liquid crystal alignment film produced by the method according to claim 2.   A liquid crystal display element comprising the liquid crystal alignment film according to claim 3.   An optical member formed by aligning a liquid crystal substance on the liquid crystal alignment film according to claim 3 and fixing the alignment state.