JP2011048048A - Liquid crystal aligning agent and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal aligning agent having excellent heat resistance and printability. <P>SOLUTION: The liquid crystal aligning agent contains a polymer selected from the group consisting of a polyamic acid and a polyimide. The polymer has a structure represented by formula (A) in its molecule (in formula (A), X<SP>I</SP>and X<SP>II</SP>each denotes -O-<SP>+</SP>, -S-<SP>+</SP>, -SO<SB>2</SB>-<SP>+</SP>, -NH-<SP>+</SP>, -COO-<SP>+</SP>, -OCO-<SP>+</SP>, -NHCO-<SP>+</SP>, -CONH-<SP>+</SP>, -CO-<SP>+</SP>, or -OCH<SB>2</SB>-<SP>+</SP>(a joint hand to which [+] is added is a benzoic acid residue side) and Y<SP>I</SP>and Y<SP>II</SP>denote a 1-50C bivalent hydrocarbon groups, respectively, and [*] denotes a joint hand). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element. More specifically, it is possible to form a liquid crystal aligning film with little deterioration in performance even when continuous driving is performed for a long time, and in addition, a liquid crystal aligning agent excellent in printability, a liquid crystal aligning film excellent in heat resistance, and a high The present invention relates to a liquid crystal display element that can display quality and does not deteriorate display quality even when a thermal stress is applied for a long time.

Currently known liquid crystal display elements can be classified into the following modes based on the electrode structure and the physical properties of the liquid crystal molecules used.
First, a liquid crystal alignment film is formed on the surface of a substrate on which a transparent conductive film is provided to form a substrate for a liquid crystal display element, and two of them are arranged opposite to each other and nematic liquid crystal having positive dielectric anisotropy in the gap is formed. A TN having a so-called TN type (twisted nematic) liquid crystal cell in which the long axis of the liquid crystal molecules is continuously twisted by 90 ° from one substrate to the other substrate by forming layers into a sandwich cell. 2. Description of the Related Art An STN (Super Twisted Nematic) type liquid crystal display element (Patent Document 2) capable of realizing a higher duty ratio than a TN type liquid crystal display element (Patent Document 1) and a TN type liquid crystal display element is known. Further, a counter electrode arrangement similar to that of the TN type liquid crystal display element is adopted, but a nematic liquid crystal layer having a negative dielectric anisotropy is injected into the electrode gap to align the liquid crystal substantially perpendicularly to the substrate. A Vertical Alignment) type display element is known (Patent Document 3). This VA type display element has a high contrast and can produce a large area display element.
On the other hand, an IPS (In-Plane Switching) type liquid crystal display element in which the driving direction of the liquid crystal when an electric field is applied is only in the in-plane direction of the substrate by arranging the electrode pair in a comb-like shape on one substrate surface (patented) Document 4), an FFS (Fringe Field Switching) type liquid crystal display element (Patent Document 5) in which the luminance is improved by changing the IPS type electrode structure and increasing the aperture ratio of the display element portion is known, Excellent viewing angle characteristics.
In addition to these, an OCB (Optical Compensated Bend) type liquid crystal display element (Patent Document 6) that has a low viewing angle dependency and excellent high-speed response of a video screen has been developed.
As materials for the liquid crystal alignment film in these liquid crystal display elements, resin materials such as polyamic acid, polyimide, polyamide, and polyester are known, and in particular, a liquid crystal alignment film made of polyamic acid or polyimide has heat resistance, mechanical strength, It has excellent affinity with liquid crystals and is used in many liquid crystal display elements (Patent Documents 1 to 4, 7 and 8).

By the way, the liquid crystal display element has been studied for various uses in recent years, and a deviation from the conventionally assumed use of the liquid crystal display element is seen. In particular, it has been actively applied to liquid crystal television applications, and combined with the progress of moving image fixing technology, it has become a reality to continuously view higher-quality display for a long time. Under such circumstances, liquid crystal alignment films are also required to have higher display quality and resistance to continuous driving for a longer time. In addition, it is believed that the phenomenon that the performance of the liquid crystal alignment film deteriorates during long-term continuous driving is caused by the liquid crystal alignment film being exposed to light for a long time. Therefore, it is considered that the continuous driving resistance is improved by using a liquid crystal alignment film material that is superior in light resistance.
On the other hand, from the viewpoint of product cost reduction, a higher product yield is required from the manufacturing site. In particular, there is a strong demand for improving the decrease in product yield due to poor printing of the liquid crystal aligning agent.
However, it exhibits a high degree of display quality, can form a liquid crystal alignment film that does not deteriorate in performance even after continuous driving for a long time, and exhibits a high degree of printability that provides such a liquid crystal alignment film with a high product yield. A liquid crystal aligning agent is not conventionally known.

JP-A-4-153622 JP 60-107020 A Japanese Patent Laid-Open No. 11-258605 JP 56-91277 A JP 2008-216572 A JP 2009-48211A US Pat. No. 5,928,733 Japanese Patent Laid-Open No. 62-165628 JP-A-6-222366 JP-A-6-281937 JP-A-5-107544

The present invention has been made in view of the above circumstances, and the object thereof is to form a liquid crystal alignment film that is excellent in display quality and that does not deteriorate in performance even when continuously driven for a long time. It is in providing the liquid crystal aligning agent which is excellent in.
Another object of the present invention is to provide a liquid crystal alignment film whose performance does not deteriorate even when continuously driven for a long time.
Still another object of the present invention is to provide a liquid crystal display element that can display a high quality and that does not deteriorate the display quality even when continuously driven for a long time.
Further 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, firstly,
At least one polymer selected from the group consisting of polyamic acid and polyimide, provided that at least a part of the polymer has the following formula (A)

(In Formula (A), X ^I and X ^II are each independently -O- ⁺ , -S- ⁺ , -SO _2- ⁺ , -NH- ⁺ , -COO- ⁺ , -OCO- ⁺ ,- NHCO- ⁺ , -CONH- ⁺ , -CO- ⁺ or -OCH _2- ⁺ (in the above, the bond with "+" is the benzoic acid residue side), and Y ^I and Y ^II Are each independently a divalent hydrocarbon group having 1 to 50 carbon atoms, and each “*” represents a bond.)
It is achieved by the liquid crystal aligning agent containing which has the structure represented by these.
The above objects and advantages of the present invention are secondly,
Achieved by a liquid crystal alignment film formed from the liquid crystal alignment agent,
Third,
This is achieved by a liquid crystal display device comprising the liquid crystal alignment film.

The liquid crystal aligning agent of the present invention can form a liquid crystal aligning film in which the liquid crystal aligning ability does not deteriorate even when continuously driven for a long time. The liquid crystal alignment film of the present invention formed from the liquid crystal aligning agent of the present invention can be suitably applied to various liquid crystal display elements.
The liquid crystal display element of the present invention having such a liquid crystal alignment film of the present invention can display a high quality, and the display quality does not deteriorate even when continuously driven for a long period of time. Therefore, the liquid crystal display element of the present invention can be suitably applied to various devices, for example, watches, portable games, word processors, notebook computers, car navigation systems, camcorders, portable information terminals, digital cameras, cellular phones. In addition, it can be used for display devices such as various monitors and liquid crystal televisions.

Hereinafter, the present invention will be described in detail.
The liquid crystal aligning agent of the present invention is at least one polymer selected from the group consisting of polyamic acid and polyimide, provided that the polymer has a structure represented by the above formula (A) in at least a part of the molecule. , Containing. Hereinafter, such a polymer is referred to as “specific polymer” in the present specification. In the specific polymer, the structure represented by the formula (A) may be present in the main chain of the polymer, may be present in the side chain of the polymer, or may be present in the polymer. It may be present in both the main chain and the side chain.

X ^I and X ^II in the above formula (A) are each preferably —O— ⁺ , —S— ⁺ , —SO ₂ − ⁺ , —NH— ⁺ or —CO— ⁺ , and —O— More preferably, it is ⁺ , -S- ⁺ or -NH- ⁺ . However, in the above, the bond with “+” is on the benzoic acid residue side.
Examples of the divalent hydrocarbon group having 1 to 50 carbon atoms of Y ^I and Y ^II include, for example, a methylene group, a linear alkylene group having 2 to 30 carbon atoms, and 2 to 3 carbon atoms having an alicyclic structure. And a divalent hydrocarbon group having 6 to 50 carbon atoms including an aromatic ring. The linear alkylene group having 2 to 30 carbon atoms is preferably a linear alkylene group having 2 to 15 carbon atoms, and more preferably a linear alkylene group having 2 to 8 carbon atoms. Specific examples of such a linear alkylene group include a 1,2-ethylene group, a 1,3-propylene group, and a 1,4-butylene group. The divalent hydrocarbon group having 3 to 50 carbon atoms having the alicyclic structure is preferably a cycloalkylene group having 4 to 10 carbon atoms, and specific examples thereof include, for example, a 1,3-cyclohexylene group. 1,4-cyclohexylene group and the like. The divalent hydrocarbon group having 6 to 50 carbon atoms containing the aromatic ring is preferably an arylene group having 6 to 14 carbon atoms. Specific examples thereof include 1,3-phenylene group, 1,4- Examples thereof include a phenylene group.
The group —X ^I —Y ^I — and group —X ^II —Y ^II — on the benzene ring in the above formula (A) are preferably in the 3,5-position with respect to the carboxyl group.
The content ratio of the structure represented by the above formula (A) in the polymer is preferably 0.005 to 0.35 mol / g, and preferably 0.025 to 0.25 mol / g. More preferred.

The polyamic acid having a structure represented by the above formula (A) in at least a part of the molecule includes, for example, a tetracarboxylic acid containing a compound represented by the above formula (A) and a compound having two carboxylic anhydride groups. By reacting a dianhydride with a diamine, or by reacting a tetracarboxylic dianhydride with a diamine containing a compound having the structure represented by the above formula (A) and two amino groups. Can get and
A polyimide having a structure represented by the above formula (A) in at least a part of the molecule can be obtained, for example, by dehydrating and ring-closing the polyamic acid obtained as described above.
As a specific polymer contained in the liquid crystal aligning agent of the present invention, a tetracarboxylic dianhydride is reacted with a diamine containing a compound having a structure represented by the above formula (A) and two amino groups. It is preferable that the polymer is at least one polymer selected from the group consisting of a polyamic acid obtained in this manner and a polyimide formed by dehydrating and ring-closing the polyamic acid.

<Tetracarboxylic dianhydride>
Examples of the tetracarboxylic dianhydride used for synthesizing a preferable polyamic acid in the liquid crystal aligning agent of the present invention include, for example, butanetetracarboxylic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride. 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro -1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3 4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetracarboxylic dianhydride 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic 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-5-methyl-5 (tetrahydro) -2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-ethyl-5- ( Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-methyl-5 (Tetrahydro-2,5-dioxo-3-fura Nyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-ethyl-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, 1,3,3a, 4,5,9b-hexahydro-8-ethyl-5- (tetrahydro-2,5-dioxo -3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5,8-dimethyl-5- (tetrahydro-2, 5-Dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3 Dione, bicyclo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 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-1,2-dicarboxylic acid Anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] Undecane-3,5,8,10-tetraone, the following formulas (TI) and (T-II)

(Wherein R ¹ and R ³ are each a divalent organic group having an aromatic ring, R ² and R ⁴ are each a hydrogen atom or an alkyl group, and a plurality of R ² and R ^{4 are present.} May be the same or different.)
An aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride such as a compound represented by each of the following:
Pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4′-bis ( 3,4-dicar Boxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidene diphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2 , 2 ′, 3,3′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis ( Triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride, ethylene glycol-bis ( Anhydrotrimellitate), propylene glycol-bis (anhydrotrimellitate), 1,4-butanediol-bis (anhydrotrimellitate) Retate), 1,6-hexanediol-bis (anhydrotrimellitate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis ( Anhydrotrimellitate), the following formulas (T-1) to (T-4)

An aromatic tetracarboxylic dianhydride such as a compound represented by The benzene ring of the aromatic tetracarboxylic dianhydride may be substituted with one or two or more alkyl groups having 1 to 4 carbon atoms (preferably a methyl group).
These tetracarboxylic dianhydrides can be used singly or in combination of two or more.
Among tetracarboxylic dianhydrides used for the synthesis of preferred polyamic acids in the present invention, among the above, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1, 3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic 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, 1,3 3a, 4,5,9b-Hexahydro-5,8-dimethyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, bicyclo [ 2.2.2] -Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 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-1,2-dicarboxylic acid anhydride, 3 , 5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3, 5,8,10-tetraone, pyromellitic dianhydride 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfonetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetra Carboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, among the compounds represented by the above formula (TI), the following formulas (T-5) to (T-7)

And the following formula (T-8) among the compounds represented by formula (T-II):

The liquid crystal alignment film to be formed exhibits good liquid crystal alignment properties when it contains at least one selected from the group consisting of the compounds represented by (hereinafter referred to as “specific tetracarboxylic dianhydride”). It is preferable from the viewpoint of becoming.
More preferably, the specific tetracarboxylic dianhydride is 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- 1,2-dicarbo Acid anhydride, 3,5,6-tricarboxy-2-carboxymethyl norbornane -2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^{2, 6} It is at least one selected from the group consisting of compounds represented by undecane-3,5,8,10-tetraone, pyromellitic dianhydride and the compound represented by the above formula (T-5).
The tetracarboxylic dianhydride used for the synthesis of a preferred polyamic acid in the present invention is one containing 50 mol% or more of the specific tetracarboxylic dianhydride as described above with respect to the total tetracarboxylic dianhydride. The content is preferably 60 mol%, more preferably 80 mol% or more.
As the tetracarboxylic dianhydride used for the synthesis of a preferable polyamic acid in the present invention, it is most preferable to use only the specific tetracarboxylic dianhydride as described above.

<Diamine>
The diamine used for synthesizing a preferable polyamic acid in the liquid crystal aligning agent of the present invention is a compound having the structure represented by the above formula (A) and two amino groups (hereinafter referred to as “compound (A)”). Is included.
As the compound (A), the following formula (A-1)

(In formula (A-1), X ^I , X ^II , Y ^I and Y ^II have the same meanings as in formula (A).)
It is preferable that it is a compound represented by the following formula (A-1-1)-(A-1-5) especially.

It is preferable to use at least one selected from the group consisting of compounds represented by each of the above.
Such a compound (A) can be synthesized by appropriately combining organic chemistry methods.
For example, in the above formula (A-1), X ^I and X ^II are each —O− ⁺ (where the bond with “+” is the benzoic acid residue side), and Y ^II is Y ^The compound having the same group as I is obtained by reacting, for example, dihydrobenzoic acid and the compound F-Y ^I -NO ₂ for about 0.1 to 12 hours at 110 to 130 ° C, preferably in the presence of potassium carbonate. It can be obtained by converting a nitro group into an amino group by a known method.
Further, ^{X I} and ^{X II} in the above formula (A-1), ^{respectively,} -S- +, -NH- ⁺ or -OCH ₂ - ⁺ (although at least a bond marked with "+" benzoic acid And the compound in which Y ^II is the same group as Y ^I uses dimercaptobenzoic acid, diaminobenzoic acid or di (hydroxymethyl) benzoic acid instead of dihydrobenzoic acid in the above. Can be obtained.
As a diamine used for synthesizing a preferred polyamic acid in the present invention, only the compound (A) may be used alone, or the compound (A) and another diamine may be used in combination.

  Examples of other diamines that can be used here include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfone, 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, 4,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 2, 2'-dimethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4'-aminophenyl)- 1,3,3-trimethylindane, 3,4'-diaminodiphenyl ether, 3,3'-diaminobenzo Enone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) Phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 4, 4'-bis (4-aminophenoxy) biphenyl, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl)- 10-hydroanthracene, 2,7-diaminofluorene, 9,9-dimethyl-2,7-diaminofluorene, 9,9-bis ( -Aminophenyl) fluorene, bis (4-amino-2-chlorophenyl) methane, 2,2 ', 5,5'-tetrachloro-4,4'-diaminobiphenyl, 2,2'-dichloro-4,4' -Diamino-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 4,4 '-(p-phenylenediisopropylidene) bisaniline, 4,4'-(m-pheny Range isopropylidene) bisaniline, 2,2′-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-3,3′-bis (trifluoromethyl) ) Biphenyl, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino-2-trifluoro) (Romethyl) phenoxy] -octafluorobiphenyl, the following formulas (D-1) to (D-5)

(Y in the formula (D-4) is an integer of 2 to 12, and z in the formula (D-5) is an integer of 1 to 5.)
An aromatic diamine such as a compound represented by each of the following:
1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 1,4-diaminocyclohexane, isophoronediamine, Tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene methylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenediethylenediamine, 4,4′-methylenebis (cyclohexylamine) ), 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane and other aliphatic and alicyclic diamines;
2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino-2,4 -Dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,3 , 5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl -S-triazine, 2,4-diamino-1,3,5-triazine, 4,6-diamino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6- Aminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5-diamino-1,2,4-triazole, 3,8-diamino-6-phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, N, N′-bis (4-aminophenyl) phenylamine, 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′-dimethyl-benzidine and Formulas (DI) and (D-II)

(In the formula (DI), R ⁵ is a monovalent organic group having a ring structure containing a nitrogen atom selected from the group consisting of pyridine, pyrimidine, triazine, piperidine and piperazine, and X ¹ is a divalent group. An organic group;
In the formula (D-II), R ⁶ is a divalent organic group having a ring structure containing a nitrogen atom selected from the group consisting of pyridine, pyrimidine, triazine, piperidine and piperazine, and X ² is 2 And a plurality of X ² may be the same or different. )
A diamine having two primary amino groups in the molecule and a nitrogen atom other than the primary amino group, such as a compound represented by each of:
The following formula (D-III)

(In the formula (D-III), R ⁷ is —O—, —COO—, —OCO—, —NHCO—, —CONH— or —CO—, and R ⁸ is a steroid skeleton, a trifluoromethylphenyl group, It is a monovalent organic group having a skeleton or group selected from the group consisting of a fluoromethoxyphenyl group and a fluorophenyl group, or an alkyl group having 6 to 30 carbon atoms.)
Monosubstituted phenylenediamines such as compounds represented by:
The following formula (D-IV)

(In the formula (D-IV), R ⁹ is a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ⁹ may be the same or different, and p is each 1 is an integer of 1 to 3, and q is an integer of 1 to 20.)
And diaminoorganosiloxanes such as compounds represented by the formula: The aromatic diamine, a diamine ring having two primary amino groups in the molecule and a nitrogen atom other than the primary amino group, and a mono-substituted phenylenediamine have one or two or more carbon atoms of 1 to 4 May be substituted with an alkyl group (preferably a methyl group). In addition, the steroid skeleton in the above formula (D-III) refers to a skeleton composed of a cyclopentano-perhydrophenanthrene nucleus or a skeleton in which one or more of the carbon-carbon bonds are double bonds.
These diamines can be used alone or in combination of two or more.
Other diamines used for synthesizing a preferred polyamic acid in the present invention include p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, and 1,5-diamino among the above. Naphthalene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 2,7-diaminofluorene, 4,4′-diamino Diphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexa Fluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 ′-(p-pheny Diisopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 1, 4-diaminocyclohexane, 4,4′-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane, compounds represented by the above formulas (D-1) to (D-5), 2, 6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 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-aminopheny ) - benzidine, N, N'-bis (4-aminophenyl) -N, N'-dimethyl-benzidine, formula of the compound represented by the above formula (D-I) (D-6)

Of the compounds represented by formula (D-II), the following formula (D-7)

Of the compounds represented by formula (D-III), dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy- 2,4-diaminobenzene, dodecanoxy-2,5-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene, the following formula (D-8) ~ (D-15)

And at least one selected from the group consisting of 1,3-bis (3-aminopropyl) -tetramethyldisiloxane among the compounds represented by formula (D-IV) , "Other specific diamine") is preferably used.
The diamine used for the synthesis of the polyamic acid in the present invention preferably contains 0.1 mol% or more, more preferably 1 to 70 mol% of the compound (A) with respect to the total diamine. It is preferable to contain 5-50 mol%. In addition to the compound (A), other specific diamines as described above are preferably contained. In this case, the use ratio of the other specific diamine is preferably 10 mol% or more, more preferably 30 to 99.9 mol%, and 50 to 99 mol% with respect to the total diamine. Is more preferable, and 50 to 95 mol% is particularly preferable.
It is preferable that the diamine used for the synthesis | combination of the polyamic acid in this invention consists only of a compound (A) and another specific diamine.

<Synthesis of polyamic acid>
The preferable polyamic acid in this invention can be obtained by making tetracarboxylic dianhydride and the diamine containing a compound (A) react.
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 a temperature of −20 ° C. to 150 ° C., more preferably 0 to 100 ° C., and preferably 0.1 to 24 hours, more preferably 0.00. 5 to 12 hours.
Examples of the organic solvent that can be used in the synthesis of the polyamic acid include an aprotic polar solvent, phenol and derivatives thereof, alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbon and the like.
Examples of the aprotic polar solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide and the like. ;
Examples of the phenol derivative include m-cresol, xylenol, halogenated phenol and the like;
Examples of the alcohol include methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, and ethylene glycol monomethyl ether;

Examples of the ketone include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone;
Examples of the ester include ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, and diethyl malonate;
Examples of the ether include diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl 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, etc .;
Examples of the halogenated hydrocarbon include dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene and the like;
Examples of the hydrocarbon include hexane, heptane, octane, benzene, toluene, xylene, isoamylpropionate, isoamylisobutyrate, and diisopentyl ether.

Among these organic solvents, one or more selected from the group consisting of an aprotic polar solvent and phenol and derivatives thereof (first group organic solvent), or one or more selected from the first group of organic solvents It is preferable to use a mixture with one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (second group organic solvent). In the latter case, the use ratio of the second group of organic solvents is preferably 50% by weight or less, more preferably 40% by weight or less, with respect to the total of the first group of organic solvents and the second group of organic solvents. Furthermore, it is preferable that it is 30 weight% or less.
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.
The polyamic acid is isolated by pouring the reaction solution into a large amount of poor solvent to obtain a precipitate, and drying the precipitate under reduced pressure, or by distilling off the solvent in the reaction solution under reduced pressure using an evaporator. It can be carried out. Further, the polyamic acid can be purified by a method of dissolving the polyamic acid again in an organic solvent and then precipitating with a poor solvent, or a method of performing the step of distilling under reduced pressure with an evaporator once or several times.

<Polyimide>
The preferred polyimide in the present invention can be obtained by dehydrating and ring-closing imidizing the preferred polyamic acid as described above.
Examples of the tetracarboxylic dianhydride used for the synthesis of the polyimide include the same compounds as the tetracarboxylic dianhydride used for the synthesis of the polyamic acid described above. The kind of preferable tetracarboxylic dianhydride and its preferable usage rate are the same as in the case of polyamic acid.
Examples of the diamine used for synthesizing a preferable polyimide in the present invention include the same diamines as those used for the synthesis of the polyamic acid. That is, the diamine used for the synthesis | combination of the preferable polyimide in this invention contains the above compounds (A), You may use only a compound (A), The said compound (A), said other diamine, May be used in combination. The types of other preferred diamines and the preferred use ratio of each diamine are the same as in the case of polyamic acid.
The polyimide in the present invention may be a completely imidized product obtained by dehydrating and cyclizing all of the amic acid structure possessed by the polyamic acid that is a precursor thereof, and 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 imidation ratio of 30% or more, and more preferably 50% or more. 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. At this time, a part of the imide ring may be an isoimide ring.

The dehydration ring closure of the polyamic acid is preferably performed by (i) a method of heating the polyamic acid, or (ii) dissolving the polyamic acid in an organic solvent, and adding a dehydrating agent and a dehydration ring closure catalyst to this solution as necessary. This is done by heating.
The reaction temperature in the method (i) of heating the polyamic acid 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 weight of the resulting polyimide may decrease. The reaction time is preferably 1.0 to 24 hours, more preferably 1.0 to 12 hours.
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. Although the usage-amount of a dehydrating agent is based on the desired imidation rate, it is preferable to set it as 0.01-20 mol with respect to 1 mol of the amic acid structure of a polyamic acid. 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. 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. The imidization rate can be increased as the amount of the dehydrating agent and dehydrating ring-closing agent is increased. Examples of the organic solvent used for the dehydration ring-closing reaction include the organic solvents exemplified above as those used for the synthesis of the 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.

  The polyimide obtained in the above method (i) may be used for the preparation of the liquid crystal aligning agent as it is, or may be used for the preparation of the liquid crystal aligning agent after purifying the obtained polyimide. On the other hand, in the above method (ii), 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. In order to remove the dehydrating agent and the dehydrating ring-closing catalyst from the reaction solution, for example, a method such as solvent replacement can be applied. The isolation and purification of the polyimide can be performed by performing the same operation as described above as the isolation and purification method of the polyamic acid.

-End-modified polymer-
The polyamic acid and the polyimide in the present invention may each be a terminal-modified polymer having a controlled molecular weight. By using the terminal-modified polymer, the coating properties of the liquid crystal aligning agent can be further improved without impairing the effects of the present invention. Such a terminal-modified polymer can be obtained by adding a molecular weight regulator to a polymerization reaction system when synthesizing a polyamic acid. Examples of molecular weight regulators include acid monoanhydrides, monoamine compounds, monoisocyanate compounds, and the like.
Examples of the acid monoanhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride, n -Hexadecyl succinic anhydride etc .;
Examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine and the like;
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, more preferably 10 parts by weight or less, based on 100 parts by weight of the total of tetracarboxylic dianhydride and diamine used when synthesizing the polyamic acid. is there.
-Solution viscosity-
The polyamic acid or polyimide obtained as described above preferably has a solution viscosity of 20 to 800 mPa · s, and a solution viscosity of 30 to 500 mPa · s when a 10% by weight solution is obtained. It is more preferable to have it.
The solution viscosity (mPa · s) of the above polymer is E for a polymer solution having a concentration of 10% by weight prepared using a good solvent for the polymer (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). It is a value measured at 25 ° C. using a mold rotational viscometer.

<Other additives>
Although the liquid crystal aligning agent of this invention contains the above specific polymers as an essential component, it may contain the other component as needed. Examples of such other components include other polymers, compounds having at least one epoxy group in the molecule (hereinafter referred to as “epoxy compound”), and functional silane compounds.
The other polymer can be used for improving the solution characteristics of the obtained liquid crystal aligning agent and the electric characteristics of the liquid crystal alignment film to be formed. Such other polymer is a polymer other than the specific polymer. For example, a polyamic acid obtained by reacting a tetracarboxylic dianhydride and a diamine not containing the compound (A) (hereinafter referred to as “other polyamic acid”). ), A 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, poly (styrene- Phenylmaleimide) derivatives, poly (meth) acrylates and the like. Of these, other polyamic acids or other polyimides are preferred.
The proportion of the other polymer used is preferably 90% by weight or less, more preferably 80% by weight based on the total of the polymers (the total of specific polymers and other polymers; the same shall apply hereinafter). % Or less.
As a polymer in the liquid crystal aligning agent of this invention, it is preferable to use only the polyimide which is a specific polymer, or to mix and use the polyimide which is a specific polymer, and another polyamic acid. When using only the polyimide which is a specific polymer as a polymer in the liquid crystal aligning agent of this invention, it is preferable that the imidation ratio is 30 to 80%, and it is more preferable that it is 30 to 70%. When mixing and using the polyimide which is a specific polymer and other polyamic acid as a polymer in the liquid crystal aligning agent of this invention, it is preferable to make the average imidation ratio into 70% or less, and to set it as 10 to 60%. Is more preferable, and 15 to 50% is particularly preferable. This average imidation ratio is the number of polyimide imide rings (PI-I) and the number of amic acid structures (PI-A) and the number of amic acid structures of polyamic acid (PA-A). ) From the following formula (1)

The value calculated by.
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, N, N, N ′, N′-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N— Diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane, 3- (N-allyl-N-glycidyl) amino B pills trimethoxysilane, 3- (N, N- diglycidyl) and aminopropyl trimethoxy silane can be cited.
The use ratio of the epoxy compound as described above 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 polymer.
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 use ratio of the functional silane compound as described above is preferably 2 parts by weight or less, more preferably 0.2 parts by weight or less, based on 100 parts by weight of the total 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.
Examples of the organic solvent that can be used in the liquid crystal aligning agent of the present invention 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, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, 3-butoxy-N, N-dimethylpropanamide, 3-methoxy-N, N-dimethylpropanamide, 3-hexyloxy-N, N-dimethylpropanamide and the like can be mentioned.

The solid content concentration in the liquid crystal aligning agent of the present invention (the ratio of the total weight of components other than the 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, and the like. However, it is preferably in the range of 1 to 10% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface as described later, and preferably, when heated, a coating film that becomes a liquid crystal aligning film is formed, but the solid content concentration is less than 1% by weight. In this case, the film thickness of the coating film becomes too small to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes excessive. Thus, a good liquid crystal alignment film cannot be obtained, and the viscosity of the liquid crystal aligning agent increases, resulting in poor coating properties.
The particularly preferable solid content concentration range varies depending on the method used when applying the liquid crystal aligning agent to the substrate. For example, when the spin coating method is used, the solid content concentration 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.
The temperature at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 10-50 degreeC, More preferably, it is 20-30 degreeC.

<Liquid crystal display element>
The liquid crystal display element of the present invention comprises a liquid crystal alignment film formed from the liquid crystal aligning agent of the present invention as described above.
Preferable operation modes in the liquid crystal display element of the present invention include TN type, STN type, VA type and IPS type.
The liquid crystal display element of the present invention can be produced, for example, by the following steps (1) to (3). In step (1), the substrate to be used varies depending on the desired operation mode. Steps (2) and (3) are common to each operation mode.

(1) First, the liquid crystal aligning agent of this invention is apply | coated on a board | substrate, Then, a coating film is formed on a board | substrate by heating an application surface.
(1-1) When manufacturing a TN type, STN type, or VA type liquid crystal display element, a pair of two substrates provided with a patterned transparent conductive film is formed on each transparent conductive film forming surface, The liquid crystal aligning agent of the present invention is preferably applied by an offset printing method, a spin coating method, a roll coating method or an ink jet printing method, respectively, and then each coated surface is heated to form a coating film. Here, as the substrate, for example, a glass such as float glass or soda glass; a transparent substrate made of a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or poly (alicyclic olefin) can be used. As a transparent conductive film provided on one surface of the substrate, an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), etc. In order to obtain a patterned transparent conductive film which can be used, for example, a method of forming a pattern by photo-etching after forming a transparent conductive film without a pattern, a mask having a desired pattern when forming the transparent conductive film The method using can be used. When applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate surface and the transparent conductive film and the coating film, a functional silane compound or functional titanium is formed on the surface of the substrate surface on which the coating film is to be formed. You may give the pretreatment which apply | coats a compound etc. previously.
After application of 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. The pre-bake time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Then, a baking (post-baking) process is implemented in order to remove a solvent completely and to thermally imidize the amic acid structure which a polymer has as needed. The firing (post-bake) temperature is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The post-bake time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. Thus, the film thickness of the formed film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.
(1-2) On the other hand, when manufacturing an IPS type liquid crystal display element, the conductive film forming surface of the substrate provided with the comb-shaped transparent conductive film and the counter substrate provided with no conductive film On one surface, the liquid crystal aligning agent of the present invention is preferably applied by an offset printing method, a spin coating method, a roll coating method or an ink jet printing method, and then each coated surface is heated to form a coating film.
The material used for the substrate and the transparent conductive film, the patterning method of the transparent conductive film, the pretreatment of the substrate, the heating method after applying the liquid crystal aligning agent, and the preferred film thickness of the coating film to be formed are as described above (1 -1).

(2) When the liquid crystal display element of the present invention is a VA type liquid crystal display element, the coating film formed as described above can be used as it is as a liquid crystal alignment film. It may be used after the rubbing treatment described in the above.
On the other hand, when manufacturing a liquid crystal display element other than the VA type, a rubbing treatment is performed on the coating film formed as described above to obtain a liquid crystal alignment film.
The rubbing treatment can be performed by rubbing the coating film surface formed as described above with a roll wound with a cloth made of fibers such as nylon, rayon, and cotton in a certain direction. Thereby, the orientation ability of a liquid crystal molecule is provided to a coating film, and it becomes a liquid crystal aligning film.
Further, for the liquid crystal alignment film formed as described above, for example, a liquid crystal as shown in Patent Document 9 (JP-A-6-222366) or Patent Document 10 (JP-A-6-281937). Treatment for changing the pretilt angle of a part of the liquid crystal alignment film by irradiating a part of the alignment film with ultraviolet rays, or liquid crystal alignment as disclosed in Patent Document 11 (Japanese Patent Laid-Open No. 5-105444) A resist film is formed on a part of the film surface, then the rubbing process is performed in a direction different from the previous rubbing process, and then the resist film is removed so that the liquid crystal alignment film has different liquid crystal alignment capabilities in each region. It is possible to improve the visual field characteristics of the liquid crystal display element obtained by the above.

(3) 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 opposed to each other. Here, when the rubbing process is performed on the coating film, the two substrates are disposed to face each other so that the rubbing directions in the respective coating films are at a predetermined angle, for example, orthogonal or antiparallel.
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.
Regardless of which method is used, the liquid crystal cell produced as described above is further heated to a temperature at which the liquid crystal used takes an isotropic phase and then gradually cooled to room temperature. It is desirable to remove.
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, 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, nematic liquid crystal, smectic liquid crystal, and the like can be used, and among these, nematic liquid crystal is preferable. In the case of a VA 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, and phenylcyclohexane liquid crystal are used. . In the case of a TN type liquid crystal cell or STN type liquid crystal cell, a nematic liquid crystal having positive dielectric anisotropy is preferable. For example, biphenyl liquid crystal, phenyl cyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane liquid crystal Pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, cubane liquid crystals, and the like are used. For example, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, and cholesteryl carbonate; chiral agents such as those sold under the trade names C-15 and CB-15 (Merck); p-decyloxybenzylidene Ferroelectric liquid crystals such as -p-amino-2-methylbutyl cinnamate may be further added and used.
As a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film in which a polarizing film called “H film” in which iodine is absorbed while polyvinyl alcohol is stretched and oriented is sandwiched between cellulose acetate protective films The polarizing plate which consists of itself can be mentioned.

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

<Synthesis of Compound (A)>
Synthesis Example A-1
Scheme 1 below

Thus, 3,5-bis (4-aminophenyloxy) benzoic acid (compound (A-1-1)) was synthesized.
In a 1,000 mL three-necked flask under a nitrogen atmosphere, 3,5-dihydrobenzoic acid 100.0 mmol (15.41 g), 4-fluoronitrobenzene 210.0 mmol (29.63 g), potassium carbonate 360.0 mmol (50.00 g) Then, 250 mL of N, N-dimethylformamide was added and mixed, and the reaction was performed at 120 ° C. with stirring for 9 hours. After completion of the reaction, 500 mL of 2N hydrochloric acid was added to the reaction mixture and stirred under acidic conditions, and the precipitate (orange powder) was collected by filtration. The obtained orange powder was washed successively with distilled water and ethanol, mixed with 250 mL of acetic acid, and stirred for 2 hours under reflux. The system was then cooled to 0 ° C. and the powder was collected by filtration. The powder was washed successively with acetic acid and ethanol, and then the solvent was removed under reduced pressure to obtain 88.3 mmol (34.98 g) of a light yellow powder of compound (A-1-1a) (yield). Rate 88.3%).
Next, under a nitrogen atmosphere, in a 500 mL three-necked flask, 85.0 mmol (33.69 g) of the compound (A-1-1a) obtained above, 4.5 g of 5 wt% palladium / carbon, 300 mL of ethanol and 100 mL of acetone were mixed. And stirred at 70 ° C. for 30 minutes. Hydrazine monohydrate 75mL was dripped here over 1 hour, Then, it reacted under stirring at 70 degreeC for 2.5 hours. After completion of the reaction, palladium / carbon was removed from the reaction mixture by Celite filtration, and then the solvent was removed under reduced pressure. The resulting viscous liquid was mixed with 200 mL of isopropyl alcohol and stirred at 100 ° C. The precipitated white powder was collected by filtration, washed with isopropyl alcohol, and then the solvent was removed under reduced pressure to remove 3,5-bis (4-aminophenyloxy) benzoic acid (compound (A-1-1)) 83. 0.2 mmol (27.98 g) was obtained (yield 97.9%).

Synthesis Example A-2
In the above Synthesis Example A-1, the above formula was obtained in the same manner as in Synthesis Example A-1, except that 100.0 mmol (15.2 g) of 3,5-diaminobenzoic acid was used instead of 3,5-dihydrobenzoic acid. 77.9 mmol (26.0 g) of the compound represented by (A-1-2) (compound (A-1-2)) was obtained.

<Synthesis of specific polymer>
Synthesis example PI-1
11.2 g (0.050 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 (Tetrahydro-2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 15.7 g (0.050 mol), and 6.1 g (0. 057 mol), 1,3-bis (3-aminopropyl) -tetramethyldisiloxane 2.5 g (0.010 mol), 3,6-bis (4-aminobenzoyloxy) cholestane 1.3 g (0.0020 mol) Mol) and 3,5-bis (4-aminophenyloxy) benzoic acid obtained in Synthesis Example A-1 above and 10.1 g (0.030 mol) of aniline as a monoamine. 8g of (0.0030 mol) was dissolved in N- methyl-2-pyrrolidone 96 g, by performing the reaction for 6 hours at 60 ° C., to obtain a solution containing a polyamic acid. A small amount of the obtained polyamic acid solution was taken, and N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 50 mPa · s.
Next, 270 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 40 g of pyridine and 41 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new γ-butyrolactone (by this solvent substitution, pyridine and acetic anhydride used for the dehydration ring closure reaction were removed from the system. The same applies hereinafter). A solution containing about 15% by weight of polyimide (PI-1) having a rate of about 95% was obtained. A small amount of the obtained polyimide solution was taken, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 6.0% by weight was 16 mPa · s.

Synthesis example PI-2
2,3,5-tricarboxycyclopentylacetic acid dianhydride 22.4 g (0.10 mol) as tetracarboxylic dianhydride and 9.9 g (0.092 mol) p-phenylenediamine as diamine, 3,6- 1.9 g (0.0030 mol) of bis (4-aminobenzoyloxy) cholestane and 1.7 g (0.005 mol) of the compound (A-1-2) obtained in Synthesis Example A-2 were added to N-methyl- A solution containing polyamic acid was obtained by dissolving in 350 g of 2-pyrrolidone and reacting at 60 ° C. for 6 hours. A small amount of the obtained polyamic acid solution was taken, N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 90 mPa · s.
Next, 170 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 17 g of pyridine and 22 g of acetic anhydride were added, and 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 γ-butyrolactone to obtain a solution containing about 15% by weight of polyimide (PI-2) having an imidization ratio of about 70%. A small amount of the obtained polyimide solution was taken, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight by adding γ-butyrolactone was 45 mPa · s.

Synthesis example PI-3
2,2.4 g (0.10 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic dianhydride and 3.2 g (0.030 mol) of p-phenylenediamine as diamine and 3 (3 5-Diaminobenzoyloxy) cholestane 10.5 g (0.020 mol) and 3,5-bis (4-aminophenyloxy) benzoic acid 16.9 g (0.050 mol) obtained in Synthesis Example A-1 were used. A solution containing polyamic acid was obtained by dissolving in 170 g of N-methyl-2-pyrrolidone and reacting at 60 ° C. for 6 hours. A small amount of the obtained polyamic acid solution was taken, and N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 55 mPa · s.
Next, 380 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 8.0 g of pyridine and 10.3 g of acetic anhydride were added, and 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 to obtain a solution containing about 15% by weight of polyimide (PI-3) having an imidization ratio of about 50%. . A small amount of the obtained polyimide solution was taken, N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 44 mPa · s.

Synthesis example PI-4
2,2.4 g (0.10 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride and 7.6 g (0.070 mol) of p-phenylenediamine as diamine, 3 (3 5-Diaminobenzoyloxy) cholestane (5.3 g, 0.010 mol) and 6.7 g (0.020 mol) of the compound (A-1-2) obtained in Synthesis Example A-2 were added to N-methyl-2- A solution containing polyamic acid was obtained by dissolving in 170 g of pyrrolidone and reacting at 60 ° C. for 6 hours. A small amount of the obtained polyamic acid solution was taken, N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 57 mPa · s.
Next, 380 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 8.0 g of pyridine and 10.3 g of acetic anhydride were added, and 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 to obtain a solution containing about 15% by weight of polyimide (PI-4) having an imidization ratio of about 50%. . A small amount of the obtained polyimide solution was taken, N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 53 mPa · s.

<Synthesis of other polymers>
[Synthesis of other polyamic acids]
Synthesis example PA-1
19.6 g (0.1 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 2,2′-dimethyl-4,4′-diaminobiphenyl as diamine. 2 g (0.1 mol) is dissolved in a mixed solvent consisting of 37 g of N-methyl-2-pyrrolidone and 330 g of γ-butyrolactone, and reacted at 40 ° C. for 3 hours to contain polyamic acid (PA-1). A solution was obtained. The solution viscosity of this solution was 160 mPa · s.
Synthesis example PA-2
9.8 g (0.050 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 10.9 g (0.050 mol) of pyromellitic dianhydride and diamine 19.8 g (0.1 mol) of 4,4′-diaminodiphenylmethane was dissolved in a mixed solvent consisting of 23 g of N-methyl-2-pyrrolidone and 206 g of γ-butyrolactone, and reacted at 40 ° C. for 3 hours. -A solution containing 10% by weight of polyamic acid (PA-2) was obtained by adding 135 g of butyrolactone. The solution viscosity of this solution was 125 mPa · s.

[Synthesis of other polyimides]
Synthesis example PI-5
11.2 g (0.050 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 (Tetrahydro-2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 15.7 g (0.050 mol), and diamine p-phenylenediamine 9.4 g (0. 087 mol), 2.5 g (0.010 mol) of 1,3-bis (3-aminopropyl) tetramethyldisiloxane and 0.96 g (0.0015 mol) of 3,6-bis (4-aminobenzoyloxy) cholestane ) And 0.28 g (0.0030 mol) of aniline as a monoamine are dissolved in 96 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. Ri, yielding a solution containing a polyamic acid. A small amount of the obtained polyamic acid solution was collected, and N-methyl-2-pyrrolidone was added to measure the solution viscosity as a solution having a polyamic acid concentration of 10% by weight of 60 mPa · s.
Next, 270 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 40 g of pyridine and 41 g of acetic anhydride were added, and 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 γ-butyrolactone to obtain a solution containing about 15% by weight of polyimide (PI-5) having an imidization ratio of about 95%. A small amount of the obtained polyimide solution was taken, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 70 mPa · s.

Synthesis example PI-6
2,2.4 g (0.10 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride and 10.5 g (0.097 mol) of p-phenylenediamine as diamine and 3,6- A solution containing polyamic acid is obtained by dissolving 1.9 g (0.0030 mol) of bis (4-aminobenzoyloxy) cholestane in 350 g of N-methyl-2-pyrrolidone and reacting at 60 ° C. for 6 hours. It was. A small amount of the obtained polyamic acid solution was taken, N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 90 mPa · s.
Next, 170 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 17 g of pyridine and 22 g of acetic anhydride were added, and 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 γ-butyrolactone to obtain a solution containing about 15% by weight of polyimide (PI-6) having an imidation ratio of about 70%. A small amount of the obtained polyimide solution was taken, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 47 mPa · s.

Synthesis example PI-7
2,2.4 g (0.10 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride and 6.5 g (0.060 mol) of p-phenylenediamine as diamine, 4,4 ′ -4.0 g (0.020 mol) of diaminodiphenylmethane and 10.5 g (0.020 mol) of 3 (3,5-diaminobenzoyloxy) cholestane are dissolved in 170 g of N-methyl-2-pyrrolidone, By performing the reaction for a time, a solution containing polyamic acid was obtained. A small amount of the obtained polyamic acid solution was collected, and N-methyl-2-pyrrolidone was added to measure the solution viscosity as a solution having a polyamic acid concentration of 10% by weight of 60 mPa · s.
Next, 380 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 8.0 g of pyridine and 10.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone to obtain a solution containing about 15% by weight of polyimide (PI-7) having an imidization ratio of about 50%. . A small amount of the obtained polyimide solution was taken, N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 47 mPa · s.

<Preparation and evaluation of liquid crystal aligning agent>
Example 1
(I) Preparation of Liquid Crystal Alignment Agent A solution containing the polyimide (PI-1) obtained in Synthesis Example PI-1 as a specific polymer and a polyamic acid (PA) obtained in Synthesis Example PA-1 as another polymer -1) is mixed so that polyimide (PI-1): polyamic acid (PA-1) = 20: 80 (weight ratio), and γ-butyrolactone (BL), N-methyl -2-pyrrolidone (NMP) and butyl cellosolve (BC) were added, and N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane was added as an epoxy compound to a total of 100 parts by weight of the polymer. 2 parts by weight was added and stirred sufficiently to obtain a solution having a solvent composition of BL: NMP: BC = 68: 17: 15 (weight ratio) and a solid content concentration of 6.0% by weight. A liquid crystal aligning agent was prepared by filtering this solution using a filter having a pore diameter of 1 μm.

(II) Evaluation of liquid crystal aligning agent (1) Evaluation of printability About the liquid crystal aligning agent prepared above, a glass substrate with a transparent electrode made of an ITO film using a liquid crystal aligning film printer (Nissha Printing Co., Ltd.) The film was coated on the transparent electrode surface, heated on a hot plate at 80 ° C. for 1 minute (pre-baked) to remove the solvent, and then heated on a hot plate at 200 ° C. for 10 minutes (post-baked) to obtain an average film thickness of 600 mm. The coating film was formed. When this coating film was observed with a microscope with a magnification of 20 times to check for the presence of printing unevenness and pinholes, neither printing unevenness nor pinholes were observed, and the printability was good.
(2) Evaluation of film thickness uniformity of coating film About the coating film formed above, the film thickness at the central part of the substrate and 15 mm from the outer edge of the substrate using a stylus film thickness meter (manufactured by KLA-Tencor) The film thickness at the position close to the center was measured, and the film thickness difference between the two was examined.
When this film thickness difference is 20 mm or less, it can be said that the film thickness uniformity of the coating film is good.

(3) Manufacture of liquid crystal cell The liquid crystal aligning agent prepared above was applied to the transparent electrode surface of the glass substrate with a transparent electrode made of an ITO film using a liquid crystal alignment film printer (Nissha Printing Co., Ltd.). After removing the solvent by heating (pre-baking) for 1 minute on an 80 ° C. hot plate, heating (post-baking) for 10 minutes on a 200 ° C. hot plate to form a coating film having an average film thickness of 600 mm. The coating film is rubbed with a rubbing machine having a roll wrapped with a rayon cloth at a roll rotation speed of 400 rpm, a stage moving speed of 3 cm / sec, and a hair foot indentation length of 0.4 mm to impart liquid crystal alignment ability. did. Thereafter, ultrasonic cleaning was performed in ultrapure water for 1 minute, followed by drying in a 100 ° C. clean oven for 10 minutes to obtain a substrate having a liquid crystal alignment film.
This operation was repeated to obtain a pair (two) of substrates having a liquid crystal alignment film.
Next, after applying an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm to the outer edges of the pair of substrates having the liquid crystal alignment film, the liquid crystal alignment film surfaces are overlapped and pressure bonded. The adhesive was cured. Next, a nematic liquid crystal (MLC-6221, manufactured by Merck & Co., Inc.) was filled between the pair of substrates from the liquid crystal inlet, and then the liquid crystal inlet was sealed with an acrylic photo-curing adhesive to produce a liquid crystal cell. .
(4) Evaluation of light resistance The liquid crystal cell produced above was subjected to a light irradiation test for 1,000 hours using a weather meter using a carbon arc as a light source.
For a liquid crystal cell after light irradiation for 1,000 hours, a voltage of 5 V was applied at 60 ° C. with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio after 167 milliseconds from the release of application was measured. . As a measuring device, VHR-1 manufactured by Toyo Corporation was used.
When the voltage holding ratio after this light irradiation is 95% or more, it can be said that the light resistance is good.

Examples 2 and 3 and Comparative Examples 1 and 2
In Example 1 above, a liquid crystal aligning agent was prepared and evaluated in the same manner as in Example 1 except that the types and amounts of the polymers contained in the polymer solution used were as shown in Table 1.
The evaluation results are shown in Table 1.
In Comparative Example 1, two other polymers were mixed and used.
In the evaluation of printability in Comparative Example 2 (1), both print unevenness and pinholes were observed, so the printability was evaluated as “bad”.

Example 4
(I) Preparation of liquid crystal aligning agent To a solution containing the polyimide (PI-3) obtained in Synthesis Example PI-3 as a specific polymer, N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) were added. Further, 2 parts by weight of N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane as an epoxy compound is added to 100 parts by weight of the polymer and sufficiently stirred, and the solvent composition is NMP: BC. = 50: 50 (weight ratio), solid content concentration 6.0 wt% solution. A liquid crystal aligning agent was prepared by filtering this solution using a filter having a pore diameter of 1 μm.
(II) Evaluation of liquid crystal aligning agent In the same manner as in Example 1, (1) evaluation of printability and (2) evaluation of film thickness uniformity of the coating film were performed.
Further, in the production of the liquid crystal cell of Example 1 (3), a liquid crystal cell was produced in the same manner as in Example 1 except that the rubbing treatment of the coating film was not performed and MLC-6608 manufactured by Merck was used as the liquid crystal. (4) Heat resistance stability was evaluated.
The evaluation results are shown in Table 1.

Example 5 and Comparative Example 3
In Example 4 above, a liquid crystal aligning agent was prepared and evaluated in the same manner as in Example 4 except that the types of polymers contained in the polymer solution used were as shown in Table 1.
The evaluation results are shown in Table 1.
In (1) evaluation of printability of Comparative Example 3, both print unevenness and pinholes were observed, and thus printability was evaluated as “bad”.

In Table 1, the abbreviations of the solvent names in the “solvent composition” column and the liquid crystal names in the “liquid crystal type” column have the following meanings, respectively.
Solvent name BL: γ-butyrolactone NMP: N-methyl-2-pyrrolidone BC: Butyl cellosolve Liquid crystal name 6221: MLC-6221, manufactured by Merck 6608: MLC-6608, manufactured by Merck

Claims (6)

At least one polymer selected from the group consisting of polyamic acid and polyimide, provided that at least a part of the polymer has the following formula (A)

(In Formula (A), X ^I and X ^II are each independently -O- ⁺ , -S- ⁺ , -SO _2- ⁺ , -NH- ⁺ , -COO- ⁺ , -OCO- ⁺ ,- NHCO- ⁺ , -CONH- ⁺ , -CO- ⁺ or -OCH _2- ⁺ (in the above, the bond with "+" is the benzoic acid residue side), and Y ^I and Y ^II Are each independently a divalent hydrocarbon group having 1 to 50 carbon atoms, and each “*” represents a bond.)
The liquid crystal aligning agent characterized by including the structure represented by these. The polymer is tetracarboxylic dianhydride and the following formula (A-1)

(In the formula (A-1), X ^I , X ^II , Y ^I and Y ^II have the same meanings as in the above formula (A).)
2. The liquid crystal according to claim 1, which is at least one polymer selected from the group consisting of a polyamic acid obtained by reacting with a diamine containing a compound represented by formula (I) and a polyimide obtained by dehydrating and ring-closing the polyamic acid. Alignment agent.   A liquid crystal alignment film formed from the liquid crystal aligning agent according to claim 1.   A liquid crystal display element comprising the liquid crystal alignment film according to claim 3.   A polyamic acid obtained by reacting a tetracarboxylic dianhydride with a diamine containing a compound represented by the above formula (A-1).   A polyimide obtained by dehydrating and ring-closing a polyamic acid obtained by reacting a tetracarboxylic dianhydride and a diamine containing a compound represented by the above formula (A-1).