JP5633677B2 - Liquid crystal alignment agent - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent. More specifically, the present invention relates to a liquid crystal aligning agent that provides a liquid crystal aligning film having suitable performance even by a photo-alignment method under little light irradiation.

Conventionally, as an operation mode of a liquid crystal display element, a liquid crystal molecule having a negative dielectric anisotropy, such as a TN (twisted nematic) type using a liquid crystal molecule having a positive dielectric anisotropy, an STN (super twisted nematic) type, etc. A VA (Vertical Alignment) type using a liquid crystal is known, and a liquid crystal alignment film mainly composed of an organic film is used for controlling the alignment of liquid crystal molecules (Patent Documents 1 to 4).
The liquid crystal alignment film in the TN type, STN type, and the like has a pretilt angle characteristic because the liquid crystal alignment film in the VA type has a constant tilt direction when driving the liquid crystal because the liquid crystal molecules are aligned at high speed. . As a method for imparting this pretilt angle characteristic, the rubbing method is generally used in the former, the rubbing method is used in the latter, and a method of providing a protrusion on the substrate surface. Of these, the rubbing method may cause problems such as display defects and circuit destruction due to dust and static electricity generated in the process, while the method of providing protrusions on the substrate surface impairs the brightness of the liquid crystal display element obtained. All of them had problems.
Therefore, as a pretilt angle providing method instead of these, a so-called photo-alignment method has been proposed by irradiating the photosensitive thin film with ultraviolet rays obliquely with respect to the film normal (Patent Document 5 and Non-Patent Document 1).

In recent years, liquid crystal display elements have been rapidly developed especially for television applications, and extraordinary long-time viewing has become a reality compared with conventional liquid crystal display elements. However, it is known that display quality deteriorates when a conventionally known liquid crystal display element is continuously driven for a long time. One of the reasons is considered to be that the liquid crystal alignment film is deteriorated by being exposed to light for a long time by being driven for a long time. For this reason, in the field of liquid crystal alignment films, materials that do not deteriorate display performance even when driven continuously for a long time have been studied.
For example, Patent Document 6 proposes the use of an alignment film material having a crosslinked structure. However, even with the technique of this document, the degree of suppression of display quality deterioration in the case of continuous driving for a long time is not sufficient.

JP 56-91277 A JP-A-1-120528 Japanese Patent Laid-Open No. 11-258605 JP 2002-250924 A JP 2004-83810 A JP 2008-216985 A JP 2010-97188 A

J. et al. of the SID 11/3, 2003, p579 T. T. et al. J. et al. Scheffer et. al. , J .; Appl. Phys. vol. 48, p1783 (1977) F. Nakano et.al. , JPN. J. et al. Appl. Phys. vol. 19, p2013 (1980)

  An object of the present invention is to provide a liquid crystal aligning agent that can provide a liquid crystal alignment film that can obtain good pretilt characteristics by a photo-alignment method and that does not deteriorate display performance even when continuously driven for a long time. There is to do.

According to the present invention, the above objects and advantages of the present invention are as follows.
Tetracarboxylic dianhydride;
The following formula (A-0)

(Formula (A-0) in, ^{X I} is a single bond, an alkylene group having a carbon number of 2 or ^{3, * -O-, * -COO-,} * -OCO-, * -X'-R 1 -, * - R ¹ -X'- or ^* -X'-R ¹ -X'- (where X 'is ⁺ -O-, ⁺ -COO- or ⁺ -OCO- (where "+" And R ¹ is an alkylene group having 2 or 3 carbon atoms, and a bond marked with “*” is attached to the bond in the formula (A-0). Bonded to a diaminophenyl group).
Ring ¹ and Ring ² are each independently a cyclohexylene group or a phenylene group,
X ″ is a single bond, ⁺ —O—, ⁺ —COO— or ⁺ —OCO— (where “+” indicates that the bond with this is directed to the left in formula (A-0).) And
a is 0 or 1, b is an integer of 0 to 3,
When b is 2 or more, a plurality of X ″ and Ring ² may be the same or different from each other. When a is 0, the position is the leftmost position in the formula (A-0). X ″ is a single bond,
c is an integer from 0 to 20 and α and β are each an integer from 0 to 2c + 1, provided that c is not 0 when α + β = 2c + 1 and a + b = 0. )
A diamine comprising a first diamine represented by and a second diamine having a photoreactive structure;
And a liquid crystal aligning agent containing at least one polymer selected from the group consisting of a polyamic acid obtained by reacting and a polyimide formed by dehydrating and ring-closing the polyamic acid.

The liquid crystal aligning agent of the present invention deteriorates the display performance even when it is continuously driven for a long time as compared with a liquid crystal aligning agent conventionally known as a liquid crystal aligning agent to which a photo-alignment method can be applied. A liquid crystal alignment film can be formed.
Therefore, when the liquid crystal alignment film of the present invention is applied to a liquid crystal display element, the obtained liquid crystal display element is excellent in various performances such as display characteristics and reliability. Therefore, the liquid crystal display element can be effectively applied to various devices, and can be suitably used for devices such as desk calculators, watches, table clocks, counting display boards, word processors, personal computers, and liquid crystal televisions.

The liquid crystal aligning agent of the present invention is as described above.
Tetracarboxylic dianhydride;
A diamine containing a first diamine represented by the above formula (A-0) and a second diamine having a photoreactive structure;
And at least one polymer selected from the group consisting of polyimides obtained by dehydrating and ring-closing the polyamic acid (hereinafter also referred to as “specific polymer”).

<Tetracarboxylic dianhydride>
Examples of the tetracarboxylic dianhydride used for synthesizing the polyamic acid in the present invention include an aliphatic tetracarboxylic dianhydride, an alicyclic tetracarboxylic dianhydride, an aromatic tetracarboxylic dianhydride, and the like. Can be mentioned. Specific examples of these include aliphatic tetracarboxylic dianhydrides such as butane tetracarboxylic dianhydride;
Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a, 4, 5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b- Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3.2.1] octane -2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene- No 1,2-dicarboxylic acid 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2 : 4,6: 8-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone and the like;
As aromatic tetracarboxylic dianhydride, for example, pyromellitic dianhydride can be mentioned, respectively,
Tetracarboxylic dianhydrides described in Patent Document 7 (Japanese Patent Laid-Open No. 2010-97188) can be used.

Among these, the tetracarboxylic dianhydride used for synthesizing the polyamic acid preferably includes an alicyclic tetracarboxylic dianhydride, and particularly 2,3,5-tricarboxycyclopentylacetic acid. Dianhydrides, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydrides and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane -2: 4, 6: 8- It is preferable that it contains at least one selected from the group consisting of dianhydrides.
Examples of the tetracarboxylic dianhydride used for synthesizing the polyamic acid include 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: At least one selected from the group consisting of 3,5: 6-dianhydride and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride The seed is preferably contained in an amount of 80 mol% or more, more preferably 90 mol% or more, based on the total tetracarboxylic dianhydride.
Examples of the tetracarboxylic dianhydride used for synthesizing the polyamic acid include 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: At least one selected from the group consisting of 3,5: 6-dianhydride and 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride Most preferably, it consists only of seeds.

<Diamine>
The diamine used for synthesizing the polyamic acid in the present invention includes the first diamine represented by the above formula (A-0) and the second diamine having a photoreactive structure. The diamine is further represented by the following formula (A-3)

(In Formula (A-3), R ^III is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and R ^IV and R ^V are each independently a hydrogen atom or a methyl group.)
And at least one selected from the group consisting of a fourth diamine that is a diamine other than the first to third diamines.

[First diamine]
The first diamine is a compound represented by the formula (A-0).
The ^{X I} in the above formula ^{(A-0), * -O-} , * -COO- or ^* -OCO- (wherein "*" bond marked with are combined with di-aminophenyl group.) It is Is preferred.
The cyclohexylene group and phenylene group of Ring ¹ and Ring ² are preferably 1,4-cyclohexylene group and 1,4-phenylene group, respectively. Ring ¹ is preferably a 1,4-phenylene group, and Ring ² is preferably a 1,4-cyclohexylene group.
X ″ is preferably a single bond.
It is preferred that α is 2c + 1 and β is 0, ie the group C _c H _α F _β − is a group C _c H _{2c + 1} −.
When a + b is an integer of 2 to 4, or when a + b is 0 or 1, c is preferably 6 or more. Among these, it is preferable that a + b is an integer of 2-4.
As a preferable structure of the compound represented by the above formula (A-0), for example, the following formula (A-1)

(In the formula (A-1), ^{X I} is ^{* -O-,} a * -COO- or ^* -OCO- (where bond marked with "*" is bonded to the diamino phenyl group.), A Is 0 or 1, b is an integer of 0 to 2, and c is an integer of 1 to 20.)
The compound represented by these can be mentioned.
The ^{X I} in the above formula (A-1), the ^* -O- or ^* -COO- (provided that a bond marked with "*" is bonded to the diamino phenyl group.) Is preferably. Specific examples of the group C _c H _{2c + 1} — include, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n -Nonyl group, n-decyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n -An eicosyl group etc. can be mentioned. The two amino groups in the diaminophenyl group are preferably in the 2,4-position or 3,5-position with respect to the other groups.
Specific examples of the compound represented by the above formula (A-1) include, for example, the following formulas (A-1-1) to (A-1-4):

And the like, and the like.
In the above formula (A-1), a and b are preferably not 0 at the same time, and a + b is more preferably 2 or 3.

[Secondary diamine]
The second diamine is a diamine having a photoreactive structure.
The above-mentioned photoreactive structures, structures der having at least one reaction that obtained by the function selected from the isomerization and dimerization by light irradiation is, exemplified by the following formulas (A-2)

(In Formula (A-2), d is 0 or 1, and A ¹ and A ² are each an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, a halogen atom, or a cyano group. Yes, e and f are each an integer of 0 to 4, and “+” indicates a bond.
In Ru structure der represented.
A ¹ and A ² in the above formula (A-2) are each preferably an alkoxyl group having 1 to 6 carbon atoms. e and f are each preferably 0.
The second diamine preferably further has a part having a function of aligning liquid crystal molecules. Examples of the photoreactive structure having such a part include the following formulas (A-2-1) and (A -2-2)

(In the formulas (A-2-1) and (A-2-2), A ¹ , A ² , d, e, and f are respectively synonymous with those in the formula (A-2),
R ^I and R ^II are each an alkyl group having 1 to 20 carbon atoms, a fluoroalkyl group having 1 to 8 carbon atoms, or a hydrocarbon group having 4 to 30 carbon atoms having an alicyclic structure,
X ^II and X ^III are respectively —O—, —CO—, —CO—O—, —O—CO—, —NR—, —NR—CO—, —CO—NR—, —NR—CO—. O—, —O—CO—NR—, —NR—CO—NR—, or —O—CO—O— (wherein R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). ,
R ^III is a methylene group, an arylene group, a divalent alicyclic group, —Si (CH ₃ ) ₂ —, —CH═CH— or —C≡C—, respectively, provided that R ^III has a hydrogen atom One or more of these may be substituted with a cyano group, a halogen atom or an alkyl group having 1 to 4 carbon atoms,
h is an integer of 1 to 6,
i is an integer from 0 to 2,
When a plurality of X ^II and R ^III are present, they may be the same as or different from each other;
j is 0 or 1, and “+” indicates a bond. )
And at least one structure selected from the structures represented by each of the above.

Examples of the alkyl group having 1 to 20 carbon atoms of R ^I and R ^{II in} the above formulas (A-2-1) and (A-2-2) include, for example, methyl group, n-butyl group, n-pentyl group, n -A hexyl group, n-heptyl group, n-octadecyl group etc. can be mentioned. The alkyl group having 1 to 20 carbon atoms of R ^I and R ^II is preferably a linear alkyl group having 1 to 12 carbon atoms from the viewpoint that good liquid crystal orientation can be expressed. A linear alkyl group having 3 to 12 carbon atoms is more preferable, and a linear alkyl group having 4 to 12 carbon atoms is particularly preferable.
The fluoroalkyl group having 1 to 8 carbon atoms of R ^I and R ^II is a linear fluoroalkyl group having 3 to 6 carbon atoms from the viewpoint that good liquid crystal orientation can be expressed. For example, 3,3,3-trifluoro-n-propyl group, 4,4,4-trifluoro-n-butyl group, 4,4,5,5,5-pentafluoro-n-pentyl group 4,4,5,5,6,6,6-heptafluorohexyl group and the like.
Specific examples of the hydrocarbon group having 4 to 30 carbon atoms having the alicyclic structure of R ^I and R ^II include, for example, a cyclohexylmethyl group, a cholestanyl group, a cholestenyl group, and a lanostannyl group.
X ^II and X ^III are each preferably —O—.
The second diamine may have one or more such photo-alignment structures in one molecule, and preferably has one or two such structures.
Specific examples of the second diamine having such a structure include, for example, the following formulas (A-2-1-1) to (A-2) having a structure represented by the above formula (A-2-1). -1-13)

As compounds having the structure represented by the above formula (A-2-2), for example, the following formula (A-2-2-1)

And the like can be mentioned respectively.

[Third diamine]
The third diamine is a compound represented by the formula (A-3).
In the above formula (A-3), each of R ^III , R ^IV and R ^V is preferably a hydrogen atom.
The two amino groups bonded to the benzene ring of the above formula (A-3) are preferably in the 2,4-position with respect to the nitrogen atom.
Most preferably, the third diamine is N, N-diallyl-2,4-diaminoaniline.

[Fourth diamine]
The fourth diamine is a diamine other than the first to third diamines, and examples thereof include aliphatic diamines, alicyclic diamines, aromatic diamines, and diaminoorganosiloxanes. Specific examples thereof include aliphatic diamines such as 1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine and the like;
Examples of alicyclic diamines include 1,4-diaminocyclohexane, 4,4′-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane and the like;
Examples of aromatic diamines include p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl ] Propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane 4,4 ′-(p-phenylenediisopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylene Riden) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diamino Pyrimidine, 3,6-diaminoacridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N , N′-bis (4-aminophenyl) -benzidine, N, N′-bis (4-aminophenyl) -N, N′-dimethylbenzidine, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy- 3,5-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate, 3, - Ranosutaniru and diaminobenzoic acid;
Examples of the diaminoorganosiloxane include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane, respectively.
Diamines described in Patent Document 7 (Japanese Patent Laid-Open No. 2010-97188) can be used.

[Composition of diamine]
The dimian used for synthesizing the polyamic acid in the present invention includes the first diamine and the second diamine as described above, and optionally from the group consisting of the third diamine and the fourth diamine. It may further contain at least one selected.
The dimian used for synthesizing the polyamic acid in the present invention is:
The first diamine is preferably contained in an amount of 1 to 50 mol%, more preferably 2 to 20 mol%, based on the total diamine;
The second diamine is preferably contained in an amount of 50 to 99 mol%, more preferably 70 to 95 mol%, based on the total diamine;
The third diamine can be contained in a range of 20 mol% or less, further in a range of 1 to 10 mol%, based on the total diamine;
The fourth diamine can be contained in a range of 20 mol% or less, and further in a range of 10 mol% or less with respect to the total diamine.
The dimian used for synthesizing the polyamic acid in the present invention consists of only the first diamine and the second diamine, or the first diamine, the second diamine and the third diamine. It is preferable that it consists only of.

[Molecular weight regulator]
When synthesizing the polyamic acid, a terminal-modified polymer may be synthesized using an appropriate molecular weight regulator together with the tetracarboxylic dianhydride and dimian as described above. By using such a terminal-modified polymer, the coating property (printability) of the liquid crystal aligning agent can be improved without impairing the effects of the present invention.
Examples of the molecular weight regulator include acid monoanhydrides, monoamine compounds, monoisocyanate compounds, and the like. Specific examples of these acid monoanhydrides include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic acid. Nic acid anhydride, n-hexadecyl succinic acid anhydride, etc .;
Examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine;
Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.
The use ratio of the molecular weight regulator is preferably 20 parts by weight or less, and more preferably 10 parts by weight or less with respect to 100 parts by weight of the total of the tetracarboxylic dianhydride and diamine used.

<Synthesis of polyamic acid>
The ratio of the tetracarboxylic dianhydride and the diamine used in the polyamic acid synthesis reaction is 0.2 to 2 for the tetracarboxylic dianhydride acid anhydride group to 1 equivalent of the amino group of the diamine. The ratio which becomes an equivalent is preferable, More preferably, it is the ratio which becomes 0.3-1.2 equivalent.
The polyamic acid synthesis reaction is preferably performed in an organic solvent, preferably at −20 ° C. to 150 ° C., more preferably at 0 to 100 ° C., preferably 0.1 to 120 hours, more preferably 0.5 to 48 hours. Done.
Here, examples of the organic solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide and the like. Protic polar solvents; mention may be made of phenolic solvents such as m-cresol, xylenol, phenol, halogenated phenol. The amount (a) of the organic solvent used is such that the total amount (b) of tetracarboxylic dianhydride and diamine is 0.1 to 50% by weight based on the total amount (a + b) of the reaction solution. It is preferable.
As described above, a reaction solution obtained by dissolving polyamic acid is obtained.
This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid contained in the reaction solution, or the isolated polyamic acid was purified. You may use for preparation of a liquid crystal aligning agent. When polyamic acid is dehydrated and cyclized into a polyimide, the above reaction solution may be directly subjected to dehydration and cyclization reaction, or may be subjected to dehydration and cyclization reaction after isolating the polyamic acid contained in the reaction solution. Alternatively, the isolated polyamic acid may be purified and then subjected to a dehydration ring closure reaction. Isolation and purification of the polyamic acid can be performed according to a known method.

<Synthesis of polyimide>
The polyimide can be obtained by dehydrating and ring-closing the polyamic acid synthesized as described above to imidize.
The polyimide in the present invention may be a completely imidized product obtained by dehydrating and cyclizing all of the amic acid structure that the polyamic acid that is a precursor thereof has, or by dehydrating and cyclizing only a part of the amic acid structure, A partially imidized product in which a structure and an imide ring structure coexist may be used. The polyimide in the present invention preferably has an imidization ratio of 30% or more, more preferably 40 to 90%. This imidation ratio represents the ratio of the number of imide ring structures to the total of the number of polyimide amic acid structures and the number of imide ring structures in percentage.
The polyamic acid is preferably dehydrated and closed by heating the polyamic acid, or by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to the solution, and heating if necessary. . Of these, the latter method is preferred.
In the method of adding a dehydrating agent and a dehydrating ring-closing catalyst to the polyamic acid solution, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride can be used as the dehydrating agent. It is preferable that the usage-amount of a dehydrating agent shall be 0.01-20 mol with respect to 1 mol of the amic acid structure of a polyamic acid. As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used. It is preferable that the usage-amount of a dehydration ring-closing catalyst shall be 0.01-10 mol with respect to 1 mol of dehydrating agents to be used. Examples of the organic solvent used in the dehydration ring-closing reaction include the organic solvents exemplified as those used for the synthesis of polyamic acid. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C, more preferably 10 to 150 ° C. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.
In this way, a reaction solution containing polyimide is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, or may be used for the preparation of the liquid crystal aligning agent after removing the dehydrating agent and the dehydrating ring-closing catalyst from the reaction solution. It may be used for the preparation of a liquid crystal aligning agent or may be used for the preparation of a liquid crystal aligning agent after purifying the isolated polyimide. These purification operations can be performed according to known methods.

<Other ingredients>
The liquid crystal alignment film of the present invention contains the specific polymer as described above as an essential component, but may contain other components as necessary. Examples of such other components include a polymer other than the specific polymer (hereinafter referred to as “other polymer”) and a compound having at least one epoxy group in the molecule (hereinafter referred to as “epoxy compound”). And functional silane compounds.

[Other polymers]
These other polymers can be used to improve solution and electrical properties. Such other polymer is a polymer other than the specific polymer as described above. For example, a polyamic acid obtained by reacting a tetracarboxylic dianhydride and a diamine not containing the second diamine (hereinafter, “ Other polyamic acid "), polyimide obtained by dehydrating and ring-closing the polyamic acid (hereinafter referred to as" other polyimide "), polyamic acid ester, polyester, polyamide, polysiloxane, cellulose derivative, polyacetal, polystyrene derivative, Examples thereof include poly (styrene-phenylmaleimide) derivatives and poly (meth) acrylates. Of these, other polyamic acids or other polyimides are preferred, and other polyamic acids are more preferred.
The tetracarboxylic dianhydride used for synthesizing the other polyamic acid or other polyimide is the same as that described above as the tetracarboxylic dianhydride used for synthesizing the specific polymer. Preferably, at least one selected from the group consisting of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and pyromellitic dianhydride is preferably used.
As the diamine used for synthesizing the other polyamic acid or other polyimide, it is possible to use at least one selected from the group consisting of the first diamine, the third diamine and the fourth diamine. Preferably, at least one selected from quaternary diamines is used. The diamine used for synthesizing other polyamic acid or other polyimide consists of at least one selected from the above-mentioned fourth diamine, and includes p-phenylenediamine, 4,4-diaminodiphenylmethane, and 4, The content of at least one selected from the group consisting of 4-diaminodiphenyl ether is preferably 50 mol% or more, more preferably 80 mol% or more, based on the total diamine used.
The use ratio of the other polymer is preferably 90% by weight or less, more preferably 50 to 50% with respect to the total of the polymers (referring to the total of the above-mentioned specific polymer and other polymers). 80% by weight.

[Epoxy compound]
Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexane. Diol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ′, N′— Tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4′-diame Diphenylmethane, N, N-diglycidyl - benzylamine, N, N-diglycidyl - such as aminomethyl cyclohexane may be mentioned as preferred. The compounding ratio of these epoxy group-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 total amount of the polymer.

[Functional silane compounds]
Examples of the functional silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl)- 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyl Trimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4 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 ( Examples thereof include oxyethylene) -3-aminopropyltrimethoxysilane and N-bis (oxyethylene) -3-aminopropyltriethoxysilane.
The blending ratio of these functional silane compounds is preferably 2 parts by weight or less, more preferably 0.02 to 0.2 parts by weight with respect to 100 parts by weight of the total amount of the polymer.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention is constituted by dissolving the specific polymer as described above and other additives optionally blended as required, preferably dissolved in an organic solvent.
As an organic solvent which can be used for the liquid crystal aligning agent of this invention, the solvent illustrated as what is used for the synthesis reaction of a polyamic acid can be mentioned. In addition, an organic solvent believed to be a poor solvent for conventional polyamic acid and polyimide can be appropriately selected and used in combination. Preferred examples of such organic solvents include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4-hydroxy-4-methyl-2- Pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i- Propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, di Examples include ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, and diisopentyl ether. These can be used alone or in admixture of two or more.

The solid content concentration of the liquid crystal aligning agent of the present invention (the ratio of the total weight of components excluding the organic solvent in the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc. However, it is preferably in the range of 1 to 10% by weight. That is, when the liquid crystal aligning agent of the present invention is applied to the substrate surface and the organic solvent is removed to form a coating film that becomes a liquid crystal aligning film, the solid content concentration is less than 1% by weight. The film thickness of this coating film may be too small to obtain a good liquid crystal alignment film. On the other hand, if the solid content concentration exceeds 10% by weight, the film thickness of the coating film will be excessive. Similarly, it may be difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal aligning agent may increase, resulting in poor coating characteristics.
The particularly preferable range of the solid content concentration 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 inkjet 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.

<Method for forming liquid crystal alignment film>
The liquid crystal aligning agent of this invention can be used conveniently in order to form a liquid crystal aligning film by the photo-alignment method.
As a method for forming a liquid crystal alignment film, for example, a liquid crystal aligning agent is applied onto a substrate to form a coating film, and the coating film is irradiated with polarized or non-polarized ultraviolet rays obliquely with respect to the coating film surface. Or a method of imparting liquid crystal alignment ability to the coating film by irradiating polarized ultraviolet rays from a direction perpendicular to the coating film surface.
First, the liquid crystal aligning agent of this invention is apply | coated to the transparent conductive film side of the board | substrate with which the pattern-shaped transparent conductive film was provided, for example by appropriate coating methods, such as a roll coater method, a spinner method, a printing method, an inkjet method. . After coating, the coated surface is preheated (prebaked) and then baked (postbaked) to form a coating film. The pre-bake conditions are, for example, 0.1 to 5 minutes at 40 to 120 ° C., and the post-bake conditions are preferably 120 to 300 ° C., more preferably 150 to 250 ° C., preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The film thickness of the coating film after post-baking is preferably 0.001-1 μm, more preferably 0.005-0.5 μm.
Examples of the substrate include glass such as float glass and soda glass; and a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, and polycarbonate.
As the transparent conductive film, a NESA film made of SnO _{2 or} an ITO film made of In ₂ O ₃ —SnO ₂ can be used. For patterning these transparent conductive films, a photo-etching method or a method using a mask when forming the transparent conductive film is used.
When applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate or the transparent conductive film and the coating film, a functional silane compound, titanate compound or the like is previously applied on the substrate and the transparent conductive film. May be.

Next, the coating film becomes a liquid crystal alignment film by imparting liquid crystal alignment ability by irradiating the coating film with polarized or non-polarized ultraviolet rays. Here, as radiation, for example, ultraviolet rays and visible light containing light having a wavelength of 150 to 800 nm can be used, but ultraviolet rays containing light having a wavelength of 300 to 400 nm are preferable. When the radiation to be used is polarized (linearly polarized light or partially polarized light), it may be irradiated from a direction perpendicular to the coating film surface or from an oblique direction for providing a pretilt angle. On the other hand, when irradiating non-polarized radiation, it is necessary to perform irradiation from an oblique direction with respect to the coating surface.
As a light source for irradiation radiation, for example, 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, or the like can be used. The ultraviolet rays in the preferable wavelength region can be obtained by means of using the light source in combination with, for example, a filter or a diffraction grating.
The irradiation dose of radiation, preferably less than 1 J / ^{m 2} or more 10,000 J / ^{m 2,} more preferably from 10~3,000J / ^{m 2.} In addition, when providing the liquid crystal aligning ability by the photo-alignment method to the coating film formed from the conventionally known liquid crystal aligning agent, the irradiation dose of 10,000 J / m < ² > or more was required. However, using the liquid crystal aligning agent of the present invention, the radiation dose at the time of photo-alignment method is 3,000 J / ^{m 2} or less, further 1,000 J / ^{m 2} or less, even more was at 300 J / ^{m 2} or less good Liquid crystal alignment ability can be imparted, which contributes to the reduction of the manufacturing cost of the liquid crystal display element.

<Method for manufacturing liquid crystal display element>
The liquid crystal display element of this invention comprises the liquid crystal aligning film formed from the liquid crystal aligning agent of this invention. The liquid crystal display element of this invention can be manufactured as follows, for example.
A liquid crystal cell is manufactured by preparing two substrates on which a liquid crystal alignment film is formed as described above, and disposing a liquid crystal between the two substrates. In order to manufacture a liquid crystal cell, the following two methods are mentioned, for example.
The first method is a conventionally known method. First, two substrates are arranged to face each other through a gap (cell gap) so that the respective liquid crystal alignment films are opposed to each other, and the peripheral portions of the two substrates are bonded using a sealant, and the substrate surface and the sealant are bonded. A liquid crystal cell can be manufactured by injecting and filling liquid crystal into the cell gap partitioned by the step, and then sealing the injection hole.
The second method is a method called an ODF (One Drop Fill) method. For example, an ultraviolet light curable sealant is applied to a predetermined location on one of the two substrates on which the liquid crystal alignment film is formed, and liquid crystal is dropped on the liquid crystal alignment film surface. The other substrate is bonded so as to face each other, and then the entire surface of the substrate is irradiated with ultraviolet light to cure the sealant, whereby a liquid crystal cell can be manufactured.
In any case, it is desirable to remove the flow alignment at the time of filling the liquid crystal by heating the liquid crystal cell to a temperature at which the liquid crystal used has an isotropic phase and then gradually cooling it to room temperature.
And the liquid crystal display element of this invention can be obtained by bonding a polarizing plate on the outer surface of a liquid crystal cell. Here, when the liquid crystal alignment film is horizontally aligned, the angle formed by the polarization direction of the irradiated linearly polarized radiation and the angle between each substrate and the polarizing plate are adjusted on the two substrates on which the liquid crystal alignment film is formed. By doing so, a liquid crystal display element having a TN type or STN type liquid crystal cell can be obtained. On the other hand, in the case where the liquid crystal alignment film is vertically aligned, the cell is configured so that the directions of easy alignment axes of the two substrates on which the liquid crystal alignment film is formed are parallel, A liquid crystal display element having a vertical alignment type liquid crystal cell can be obtained by bonding so that the polarization direction forms an angle of 45 ° with the easy alignment axis.

As the sealing agent, for example, an aluminum oxide sphere as a spacer and an epoxy resin containing a curing agent can be used.
As the liquid crystal, for example, nematic liquid crystal or smectic liquid crystal can be preferably used.
In the case of a TN type liquid crystal cell or an STN type liquid crystal cell, a nematic type liquid crystal having positive dielectric anisotropy is preferable. For example, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, an ester liquid crystal, a terphenyl liquid crystal, a biphenylcyclohexane liquid crystal, Pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, cubane liquid crystals and the like are used. In addition, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonate, cholesteryl carbonate; chiral agents such as those sold under the trade names “C-15” and “CB-15” (manufactured by Merck); p- A ferroelectric liquid crystal such as decyloxybenzylidene-p-amino-2-methylbutylcinnamate may be further added and used.
On the other hand, in the case of a vertical alignment type liquid crystal cell, a nematic liquid crystal having negative dielectric anisotropy is preferable. For example, dicyanobenzene liquid crystal, pyridazine liquid crystal, Schiff base liquid crystal, azoxy liquid crystal, biphenyl liquid crystal, phenyl cyclohexane. System liquid crystal or the like is used.
The polarizing plate used outside the liquid crystal cell is composed of a polarizing film called “H film” in which polyvinyl alcohol is stretched and oriented while absorbing iodine and sandwiched between cellulose acetate protective films, or the H film itself. A polarizing plate etc. can be mentioned.
The liquid crystal display element of the present invention thus produced has excellent display performance and does not deteriorate even when used for a long time.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
In the following synthesis examples, the polymer solution viscosity and the polyimide imidation rate were evaluated by the following methods.
[Solution viscosity of polymer]
The solution viscosity (mPa · s) of the polymer was measured at 25 ° C. using an E-type viscometer for each polymer solution.
[Imidation rate of polyimide]
A small amount of the solution containing the polyimide obtained in each synthesis example was collected and poured into pure water, and the resulting precipitate was collected by filtration to isolate the polyimide. The polyimide was sufficiently dried at room temperature under reduced pressure, dissolved in deuterated dimethyl sulfoxide, and calculated from the following formula (1) from ¹ H-NMR measured at room temperature using tetramethylsilane as a reference substance.
Imidation rate (%) = (1-A ¹ / A ² × α) × 100 (1)
(In Formula (1), A ¹ is a peak area derived from protons of NH groups appearing in the vicinity of 10 ppm, A ² is a peak area derived from other protons, and α is NH in a polyimide precursor (polyamic acid). This is the ratio of the number of other protons to one proton in the group.

<Synthesis Examples and Comparative Synthesis Examples of Specific Polymer>
[Synthesis example of polyamic acid]
Synthesis Examples PA-1 to PA-24 and RPA-1 to RPA-6
In 135 g of N-methyl-2-pyrrolidone, the diamine and tetracarboxylic dianhydride of the type and amount shown in Table 1 were added and dissolved in this order, and the total weight of the diamine and tetracarboxylic dianhydride was By making the solution 10% by weight with respect to the total weight of the reaction solution and reacting it at 60 ° C. for 6 hours, polyamic acids (PA-1) to (PA-24) and (RPA-1) to (RPA-1) 150 g of each solution containing 10% by weight of -6) was obtained. The viscosities of the solutions obtained here are also shown in Table 1.
[Synthesis of polyimide]
Synthesis Examples PI-1 to PI-18 and RPI-1 to RPI-6
In 135 g of N-methyl-2-pyrrolidone, diamine and tetracarboxylic dianhydride of the types and amounts shown in Table 2 were added in this order and dissolved, and the total weight of diamine and tetracarboxylic dianhydride was A solution of 10% by weight with respect to the total weight of the reaction solution was reacted at 60 ° C. for 6 hours to obtain 150 g of a solution containing 10% by weight of polyamic acid. The viscosities of the solutions obtained here are also shown in Table 1.
Next, pyridine and acetic anhydride in the amounts shown in Table 2 were added to each of the solutions containing each of these polyamic acids, and a dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone (in this operation, pyridine and acetic anhydride used for the dehydration ring-closing reaction were removed from the system) to obtain polyimide. A solution containing 15% by weight of (PI-1) to (PI-18) and (RPI-1) to (RPI-6) was obtained. The yield of each solution, a small amount of each solution was sampled, N-methyl-2-pyrrolidone was added and diluted to 10% by weight, and the measured solution viscosity and imidation ratio of each polyimide are shown in Table 2. Also shown.

In Tables 1 and 2, the abbreviations for diamine and tetracarboxylic dianhydride have the following meanings, respectively.
[Diamine]
First diamine d-15: Compound represented by formula (A-1-1) d-16: Compound represented by formula (A-1-2) d-17: Formula (A-1) -3) Compound d-18: Compound represented by the above formula (A-1-4) Second diamine d-1: Compound represented by the above formula (A-2-1-1) d-2: Compound represented by the above formula (A-2-1-2) d-3: Compound represented by the above formula (A-2-1-1-3) d-4: The above formula (A-2) -1-4) Compound d-5: Compound represented by the above formula (A-2-2-1) d-6: Compound represented by the above formula (A-2-1-5) d-7: Compound represented by the above formula (A-2-1-6) d-8: Compound represented by the above formula (A-2-1-7) d-9: The above formula (A-2) -1-8) compound d-10: above Compound represented by formula (A-2-1-9) d-11: Compound represented by formula (A-2-1-10) d-12: Formula (A-2-1-11) D-13: compound represented by the above formula (A-2-1-12) d-14: compound represented by the above formula (A-2-1-13) third diamine d -19: N, N-diallyl-2,4-diaminoaniline quaternary diamine d-20: Cholestanyl 3,5-diaminobenzoate [tetracarboxylic dianhydride]
t-1: 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride t-2: 2,4,6,8-tetracarboxybicyclo [3.3. 0] octane-2: 4,6: 8-dianhydride t-3: 2,3,5-tricarboxycyclopentylacetic acid dianhydride

<Synthesis examples of other polymers>
[Synthesis of other polyamic acids]
Synthesis example OPA-1
1,2,3,4-Cyclobutanetetracarboxylic dianhydride 98 g (0.50 mol) and pyromellitic dianhydride 110 g (0.50 mol) as tetracarboxylic dianhydride and 4,4 ′ as diamine -200 g (1.0 mol) of diaminodiphenylmethane was dissolved in 2,100 g of a mixed solvent consisting of 230 g of N-methyl-2-pyrrolidone and γ-butyrolactone, reacted at 40 ° C. for 3 hours, γ-butyrolactone 1, By adding 350 g, a solution containing 10% by weight of polyamic acid (OPA-1) was obtained. The solution viscosity of this polyamic acid solution was 125 mPa · s.
Synthesis example OPA-2
200 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 210 g of 2,2′-dimethyl-4,4′-diaminobiphenyl as diamine (1. 0 mol) is dissolved in a mixed solvent consisting of 370 g of N-methyl-2-pyrrolidone and 3,300 g of γ-butyrolactone, and reacted at 40 ° C. for 3 hours to contain 10% by weight of polyamic acid (OPA-2) A solution was obtained. The solution viscosity of this polyamic acid solution was 160 mPa · s.

Example 1
I. Preparation of liquid crystal aligning agent As a polymer, a solution containing the polyamic acid (PA-1) obtained in Synthesis Example PA-1 and a solution containing the polyamic acid (OPA-1) obtained in Synthesis Example OPA-1 Are mixed so that polyamic acid (PA-1): polyamic acid (OPA-1) = 20: 80 (weight ratio), and γ-butyrolactone (BL), N-methyl-2-pyrrolidone (NMP) ) And butyl cellosolve (BC) were added and sufficiently stirred to obtain a solution having a solvent composition of BL: NMP: BC = 30: 20: 50 (weight ratio) and a solid concentration of 3% by weight. A liquid crystal aligning agent was prepared by filtering this solution using a filter having a pore diameter of 1 μm.
II. Manufacture of liquid crystal cell The liquid crystal aligning agent prepared above is applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film by a spin coating method, and heated (prebaked) on a hot plate at 80 ° C. for 1 minute to remove the solvent. After the removal, the film was heated (post-baked) for 40 minutes in an oven at 200 ° C. in which the interior of the chamber was replaced with nitrogen to form a coating film having an average film thickness of 1,000 mm. Next, the surface of the coating film was irradiated with polarized ultraviolet rays 200 J / m ² containing an emission line having a wavelength of 313 nm using a Hg—Xe lamp and a Grand Taylor prism from a direction inclined by 40 ° from the normal line of the coating film to obtain liquid crystal orientation. To give a liquid crystal alignment film. The same operation was repeated to manufacture a pair (two) of substrates having a liquid crystal alignment film.
After applying an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm to the outer periphery of the surface having one liquid crystal alignment film of the above substrates by screen printing, the liquid crystal alignment film surfaces of the pair of substrates are arranged to face each other. The adhesive was pressure-bonded so that the projection direction of the ultraviolet optical axis of each substrate onto the substrate surface was antiparallel, and the adhesive was thermally cured at 150 ° C. for 1 hour. Next, after filling the gap between the substrates from the liquid crystal injection port with negative type liquid crystal (MLC-6608, manufactured by Merck), 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, this was heated to 120 ° C. and then gradually cooled to room temperature to produce a liquid crystal cell.
The liquid crystal cell was evaluated for liquid crystal orientation, pretilt angle and voltage holding ratio by the following methods. The evaluation results are shown in Table 3.

III. Evaluation of liquid crystal cell (1) Evaluation of liquid crystal orientation With respect to the liquid crystal cell produced above, the presence or absence of an abnormal domain was observed with a polarizing microscope when a voltage of 5 V was turned ON / OFF (applied / released) at 25 ° C. The case where there was no abnormal domain was evaluated as “good” liquid crystal alignment.
(2) Evaluation of pretilt angle Non-patent document 2 (TJ Scheffer et.al., J. Appl.Phys.vol.48, p1783 (1977)) and non-patent document 3 (F. Nakano, et.al. , JPN.J.Appl.Phys.vol.19, p.2013 (1980)), the pretilt angle was measured by a crystal rotation method using He-Ne laser light.
(3) Evaluation of light resistance After the voltage of 5 V is applied to the liquid crystal cell produced above at 70 ° C. with a 60 microsecond application time and a 167 millisecond span, the voltage is maintained after 167 millisecond from release of application. The rate was measured by “VHR-1” manufactured by Toyo Corporation (Initial voltage holding ratio (VH _IN )). Next, the liquid crystal cell was irradiated with light for 5,000 hours using a weather meter using a carbon arc as a light source, and the voltage holding ratio was measured again for the liquid crystal cell after the light irradiation by the same method as above (irradiation). Post voltage holding ratio (VH _AF )).
At this time, when the voltage holding ratio maintenance ratio ((VH _AF ) / (VH _IN )) is 90% or more, the light resistance is “good”, and when it is less than 90%, the light resistance is It can be said that it is “bad”.
(4) Evaluation of residual DC voltage In the liquid crystal cell immediately after turning off the DC voltage by applying a 30 Hz, 3 V rectangular wave with 5 V DC superimposed on the liquid crystal cell manufactured above at an ambient temperature of 60 ° C. for 2 hours. The residual voltage (residual DC voltage) was obtained by the flicker-erasing method. This value is an indicator of afterimage characteristics. When this value is approximately 150 mV or less, the afterimage characteristics are good. When this value is approximately 50 mV or less, the afterimage characteristics are particularly excellent.

Examples 2-51 and Comparative Examples 1-12
In Example 1 above, a liquid crystal aligning agent was prepared in the same manner as in Example 1 except that the types and amounts of polymers shown in Table 3 were used as the polymer, and a liquid crystal cell was produced and evaluated. .
The evaluation results are shown in Table 3.

Claims (12)

Tetracarboxylic dianhydride;
The following formula (A-0)

(Formula (A-0) in, ^{X I} is a single bond, an alkylene group having a carbon number of 2 or ^{3, * -O-, * -COO-,} * -OCO-, * -X'-R 1 -, * - R ¹ -X'- or ^* -X'-R ¹ -X'- (where X 'is ⁺ -O-, ⁺ -COO- or ⁺ -OCO- (where "+" And R ¹ is an alkylene group having 2 or 3 carbon atoms, and a bond marked with “*” is attached to the bond in the formula (A-0). Bonded to a diaminophenyl group).
Ring ¹ and Ring ² are each independently a cyclohexylene group or a phenylene group,
X ″ is a single bond, ⁺ —O—, ⁺ —COO— or ⁺ —OCO— (where “+” indicates that the bond with this is directed to the left in formula (A-0).) And
a is 0 or 1, b is an integer of 0 to 3,
When b is 2 or more, a plurality of X ″ and Ring ² may be the same or different from each other. When a is 0, the position is the leftmost position in the formula (A-0). X ″ is a single bond,
c is an integer from 0 to 20 and α and β are each an integer from 0 to 2c + 1, provided that c is not 0 when α + β = 2c + 1 and a + b = 0. )
A first diamine represented by
The following formula (A-2)

(In Formula (A-2), d is 0 or 1, and A ¹ and A ² are each an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, a halogen atom, or a cyano group. Yes, e and f are each an integer of 0 to 4, and “+” indicates a bond.
A diamine containing a second diamine having a photoreactive structure represented by :
A liquid crystal aligning agent comprising: a polyamic acid obtained by reacting a polyamic acid; and at least one polymer selected from the group consisting of polyimides obtained by dehydrating and ring-closing the polyamic acid. Said 1st diamine is a following formula (A-1).

(In the formula (A-1), ^{X I} is ^{* -O-,} a * -COO- or ^* -OCO- (where bond marked with "*" is bonded to the diamino phenyl group.), A Is 0 or 1, b is an integer of 0 to 2, and c is an integer of 1 to 20.)
The liquid crystal aligning agent of Claim 1 which is a compound represented by these.   The liquid crystal aligning agent of Claim 1 whose a + b is an integer of 2-4 in the said formula (A-0).   The liquid crystal aligning agent of Claim 2 whose a + b is 2 or 3 in the said formula (A-1). The structure represented by the above formula (A-2) has the following formulas (A-2-1) and (A-2-2):

(In the formulas (A-2-1) and (A-2-2), A ¹ , A ² , d, e, and f are respectively synonymous with those in the formula (A-2),
R ^I and R ^II are each an alkyl group having 1 to 20 carbon atoms, a fluoroalkyl group having 1 to 8 carbon atoms, or a hydrocarbon group having 4 to 30 carbon atoms having an alicyclic structure,
X ^II and X ^III are respectively —O—, —CO—, —CO—O—, —O—CO—, —NR—, —NR—CO—, —CO—NR—, —NR—CO—. O—, —O—CO—NR—, —NR—CO—NR—, or —O—CO—O— (wherein R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). ,
R ^III is a methylene group, an arylene group, a divalent alicyclic group, —Si (CH ₃ ) ₂ —, —CH═CH— or —C≡C—, respectively, provided that R ^III has a hydrogen atom One or more of these may be substituted with a cyano group, a halogen atom or an alkyl group having 1 to 4 carbon atoms,
h is an integer of 1 to 6,
i is an integer from 0 to 2,
When a plurality of X ^II and R ^III are present, they may be the same as or different from each other;
j is 0 or 1, and “+” indicates a bond. )
Of at least one structure selected from structures represented by each liquid crystal aligning agent of claim 1. The tetracarboxylic dianhydride is 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride and 2,4,6,8 tetracarboxylic bicyclo [3.3.0] octane -2: 4,6: those containing at least one selected from the 8-second group consisting of anhydrides, claim 1-5 Liquid crystal aligning agent as described in any one of these. The diamine is represented by the following formula (A-3)

(In Formula (A-3), R ^III is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and R ^IV and R ^V are each independently a hydrogen atom or a methyl group.)
The liquid crystal aligning agent as described in any one of Claims 1-6 which further contains the 3rd diamine represented by these. Tetracarboxylic dianhydride;
A diamine not containing the second diamine, and
At least one polymer a polyamic acid and the polyamic acid obtained by reacting selected from the group consisting of polyimide obtained by dehydration ring closure further comprises, according to any one of claims 1-7 Liquid crystal aligning agent. And wherein the formed liquid crystal alignment agent according to any one of claims 1-8, a liquid crystal alignment film. A liquid crystal display device comprising the liquid crystal alignment film according to claim 9 . Tetracarboxylic dianhydride;
Under following formula (A-0)

(Formula (A-0) in, ^{X I} is a single bond, an alkylene group having 2 or 3 carbon ^{atoms, * -O-, * -COO-, *} -OCO-, * -X'-R 1 -, * - R ¹ -X'- or ^* -X'-R ¹ -X'- (where X 'is ⁺ -O-, ⁺ -COO- or ⁺ -OCO- (where "+" And R ¹ is an alkylene group having 2 or 3 carbon atoms, and a bond marked with “*” is attached to the bond in the formula (A-0). Bonded to a diaminophenyl group).
Ring ¹ and Ring ² are each independently a cyclohexylene group or a phenylene group,
X ″ is a single bond, ⁺ —O—, ⁺ —COO— or ⁺ —OCO— (where “+” indicates that the bond with this is directed to the left in formula (A-0).) And
a is 0 or 1, b is an integer of 0 to 3,
When b is 2 or more, a plurality of X ″ and Ring ² may be the same or different from each other. When a is 0, the position is the leftmost position in the formula (A-0). X ″ is a single bond,
c is an integer from 0 to 20 and α and β are each an integer from 0 to 2c + 1, where α + β = 2c + 1, and
When a + b = 0, c is never 0. )
A first diamine represented by
The following formula (A-2)

(In Formula (A-2), d is 0 or 1, and A ¹ and A ² are each an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, a halogen atom, or a cyano group. Yes, e and f are each an integer of 0 to 4, and “+” indicates a bond.
A diamine containing a second diamine having a photoreactive structure represented by :
A polyamic acid obtained by reacting. Tetracarboxylic dianhydride;
Under following formula (A-0)

(Formula (A-0) in, ^{X I} is a single bond, an alkylene group having 2 or 3 carbon ^{atoms, * -O-, * -COO-, *} -OCO-, * -X'-R 1 -, * - R ¹ -X'- or ^* -X'-R ¹ -X'- (where X 'is ⁺ -O-, ⁺ -COO- or ⁺ -OCO- (where "+" And R ¹ is an alkylene group having 2 or 3 carbon atoms, and a bond marked with “*” is attached to the bond in the formula (A-0). Bonded to a diaminophenyl group).
Ring ¹ and Ring ² are each independently a cyclohexylene group or a phenylene group,
X ″ is a single bond, ⁺ —O—, ⁺ —COO— or ⁺ —OCO— (where “+” indicates that the bond with this is directed to the left in formula (A-0).) And
a is 0 or 1, b is an integer of 0 to 3,
When b is 2 or more, a plurality of X ″ and Ring ² may be the same or different from each other. When a is 0, the position is the leftmost position in the formula (A-0). X ″ is a single bond,
c is an integer from 0 to 20 and α and β are each an integer from 0 to 2c + 1, where α + β = 2c + 1, and
When a + b = 0, c is never 0. )
A first diamine represented by
The following formula (A-2)

(In Formula (A-2), d is 0 or 1, and A ¹ and A ² are each an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, a halogen atom, or a cyano group. Yes, e and f are each an integer of 0 to 4, and “+” indicates a bond.
A diamine containing a second diamine having a photoreactive structure represented by :
Polyimide obtained by dehydrating and ring-closing polyamic acid obtained by reacting.