JP4458299B2 - Liquid crystal aligning agent and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent and a liquid crystal display element.

Currently, as a liquid crystal display element, a liquid crystal alignment film is formed on the surface of a substrate on which a transparent conductive film is provided to form a liquid crystal display element substrate. A so-called TN type (twisted) in which a layer of a nematic liquid crystal having a property is formed into a sandwich cell and the major axis of liquid crystal molecules is continuously twisted by 90 ° from one substrate to the other. A TN liquid crystal display element having a (Nematic) liquid crystal cell is widely known. In addition, an STN (Super Twisted Nematic) type liquid crystal display element capable of realizing a high contrast ratio as compared with a TN type liquid crystal display element, an IPS (In-Plane Switching) type liquid crystal display element having less viewing angle dependency, and a VA (Vertical Alignment). An OCB (Optical Compensated Bend) type liquid crystal display element has been developed which has a small viewing angle dependency and excellent high-speed response of a video screen.
As a material of the liquid crystal aligning agent in these liquid crystal display elements, polyamic acid, polyimide, polyamide, polyester and the like are known. In particular, a liquid crystal aligning film made of polyamic acid or polyimide has heat resistance, mechanical strength, and liquid crystal. It has excellent affinity and is used in many liquid crystal display elements.

A liquid crystal alignment film made of polyamic acid or polyimide forms a thin film mainly composed of a polymer obtained from tetracarboxylic dianhydride and diamine on a substrate, and this is rubbed with an appropriate cloth material such as rayon ( Rubbing method) or, if the thin film has a group that isomerizes in response to radiation, by irradiating it with radiation (photo-alignment method), etc. can get. The polyamic acid or polyimide obtained using 2,3,5-tricarboxycyclopentylacetic acid dianhydride as at least a part of the raw material tetracarboxylic dianhydride has various properties such as liquid crystal orientation and electrical properties. It is reported that it is excellent in performance (see Patent Documents 1 to 5), and is suitably used as a liquid crystal alignment film.
However, in recent years, there has been a strong demand for reducing the price of various liquid crystal panels, and accordingly, in each process of manufacturing an alignment film, reduction of process time and improvement of product yield are required at a much higher level than before. It is becoming. In particular, improvement in the uniformity of the coating film is required in the coating process of the liquid crystal aligning agent solution, but conventionally known liquid crystal aligning agents do not meet such high level requirements.
JP-A 61-205924 Japanese Patent Laid-Open No. 62-165628 JP 2000-336168 A JP 2004-325545 A JP 2007-47222 A JP-A-6-222366 JP-A-6-281937 JP-A-5-107544

  This invention is made | formed in view of the said situation, The objective is to provide the liquid crystal aligning agent which was excellent in various performances, such as liquid crystal aligning property and an electrical property, and the applicability | paintability was improved.

As a result of intensive studies to achieve the above object, the present inventors have found that 2,3,5-tricarboxycyclopentylacetic acid dianhydride used in at least a part of tetracarboxylic dianhydride as a raw material for polyamic acid or polyimide. The present invention was reached by finding that there is a relationship between the three-dimensional structure of the product and the coating properties of the obtained liquid crystal aligning agent.
That is, the above object of the present invention is as follows.
At least one heavy selected from the group consisting of a polyamic acid obtained by reaction of a tetracarboxylic dianhydride including 2,3,5-tricarboxycyclopentylacetic dianhydride with a diamine and an imidized product of the polyamic acid. A liquid crystal aligning agent containing a coalescence,
This is achieved by a liquid crystal aligning agent having an exo body content of 2,3,5-tricarboxycyclopentylacetic dianhydride of 90% or more.
The above object of the present invention is secondly,
This is achieved by a liquid crystal display device comprising a liquid crystal alignment film obtained from the liquid crystal alignment agent.

<2,3,5-tricarboxycyclopentyl acetic acid dianhydride>
The 2,3,5-tricarboxycyclopentyl acetic acid dianhydride used in the present invention has an exo body content of 90% or more.
As the steric structure of 2,3,5-tricarboxycyclopentylacetic acid dianhydride, the following formula (A)

Exo body represented by the following formula (B)

An endo body represented by the formula is known. The exo body content is defined as the ratio (%) of the 2,3,5-tricarboxycyclopentylacetic acid dianhydride as the raw material to the total amount of the exo body and the endo body. The exo body content is preferably 95% or more, and more preferably 99% or more.
The exo body content can be known by ¹ H-NMR measurement and ¹³ C-NMR of 2,3,5-tricarboxycyclopentylacetic acid dianhydride.
Such a steric 2,3,5-tricarboxycyclopentylacetic acid dianhydride can be obtained, for example, by the following method.
That is, first, hydroxydicyclopentadiene obtained by hydrating dicyclopentadiene is used as a raw material, and this is used at least in the initial stage of the reaction (preferably at least 30 minutes from the start of the reaction, more preferably at least 1 hour, more preferably at least In 2 hours), 2,3,5-tricarboxycyclopentylacetic acid having a controlled steric structure can be obtained by oxidation at a temperature of less than 50 ° C., preferably 45 ° C. or less. Here, it is preferable to control the temperature to 50 ° C. or lower throughout the oxidation reaction. For this oxidation reaction, for example, an appropriate oxidation method such as nitric acid oxidation using ammonium vanadate as a catalyst can be employed. The 2,3,5-tricarboxycyclopentylacetic acid obtained here is preferably purified by an appropriate method such as acid precipitation and then used for the next step. Next, 2,3,5-tricarboxycyclopentylacetic acid with controlled steric structure is subjected to dehydration and cyclization under controlled conditions at 60 ° C. or lower to form 2,3,5-tricarboxycyclopentylacetic acid dianhydride with controlled steric structure. You can get things. This dehydration reaction can be performed using a known dehydrating agent such as acetic anhydride or propionic anhydride. In this dehydration reaction, it is preferable not to use a dehydration ring closure catalyst. Further, if necessary, appropriate purification such as recrystallization may be performed once or a plurality of times.
By optimizing the reaction conditions with a high exo isomer content and the above-described method, 2,3,5-tricarboxycyclopentylacetic dianhydride having substantially 100% exo isomer can be obtained.

<Other tetracarboxylic dianhydrides>
The polyamic acid or imidized product thereof used in the present invention is obtained by reacting a tetracarboxylic dianhydride containing 2,3,5-tricarboxycyclopentylacetic dianhydride having the above three-dimensional structure with a diamine. It is.
Other tetracarboxylic dianhydrides that can be used together with 2,3,5-tricarboxycyclopentylacetic dianhydride having an exo-form content of 90% or more in producing the polyamic acid or imidized product thereof used in the present invention As, for example, butanetetracarboxylic dianhydride, 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, 3,5,6-tricarboxynorbornane-2-acetic 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-furanyl) -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-hexahydride -5,8-dimethyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofura L) -3-Methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, 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 anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride, 4, 9-dioxatricyclo [5.3.1.0 ^{2 6]} undecane -3,5,8,10- tetraone the following formula (T-I) and (T-II)

(In the formula, R ¹ and R ³ each independently represent a divalent organic group having an aromatic ring, R ² and R ⁴ each independently represent a hydrogen atom or an alkyl group, and a plurality of R present in the same molecule. ² and R ⁴ may be the same or different.
An aliphatic or alicyclic tetracarboxylic dianhydride such as a compound represented by:
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 , 3 ′, 2,3′-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 These may be used alone or in combination of two or more.
Of these, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic 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, -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 Acid anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-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′-biphenylsulfonetetra Carboxylic dianhydride, 2,3 ′, 2,3′-biphenyl Among the compounds represented by formula (T-5) to (T-7), of tetratetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, and the compound represented by the above formula (TI) )

Of the compounds represented by formula (I) and the compound represented by formula (T-II), the following formula (T-8)

Is preferable from the viewpoint of exhibiting good liquid crystal alignment. Particularly preferred are 1,2,3,4-cyclobutanetetracarboxylic 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-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxy Norbornane-2: 3,5: - dianhydride, 4,9-dioxatricyclo "5.3.1.0 ^{2, 6"} undecane -3,5,8,10- tetraone, pyromellitic dianhydride and the above formula (T-5 ) Can be mentioned.
When other polycarboxylic acid dianhydrides are used together with 2,3,5-tricarboxycyclopentylacetic acid dianhydride having an exo body content of 90% or more in producing the polyamic acid or imidized product thereof used in the present invention, other The amount of tetracarboxylic dianhydride used is preferably 60 mol% or less, more preferably 30 mol% or less, based on the total tetracarboxylic dianhydride.

<Diamine>
Examples of the diamine that can be used in producing the polyamic acid or imidized product thereof according to the present invention 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, 3,3′-dimethyl-4,4′-diaminobiphenyl, 2,2′-ditrifluoromethyl-4,4 ′ -Diaminobiphenyl, 3,3'-ditrifluoromethyl-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′-diaminobenzophenone, 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, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4- Bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, , 9-bis (4-aminophenyl) -10-hydroanthracene, 2,7-diaminofluorene, 9,9-dimethyl-2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 4, , 4′-methylene-bis (2-chloroaniline), 2,2 ′, 5,5′-tetrachloro-4,4′-diaminobiphenyl, 2,2′-dichloro-4,4′-diamino-5 , 5′-dimethoxybiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 1,4,4 ′-(p-phenyleneisopropylidene) bisaniline, 4,4 ′-(m-phenyleneisopropylidene) Bisaniline, 2,2′-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoro) Methyl) biphenyl, 4,4'-bis [(4-amino-2-trifluoromethyl) phenoxy] - aromatic diamines such as octafluoro biphenyl;

1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophorone diamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene methylene diamine, tricyclo [6.2.1.0 ^2,7 ] undecylenedimethyl diamine, 4, Aliphatic and cycloaliphatic diamines such as 4'-methylenebis (cyclohexylamine);
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, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6 Phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl -3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N, N'-di (4-aminophenyl) -benzidine, the following formula (DI)

(In the formula (DI), R ⁵ is a divalent group selected from —O—, —COO—, —OCO—, —NHCO—, —CONH— and —CO—, and one R ⁶ is A monovalent hydrocarbon group having 1 to 40 carbon atoms which may contain the above unsaturated bond, provided that part or all of the hydrogen atoms of the monovalent hydrocarbon group are substituted by fluorine atoms. May be.)
A compound represented by formula (D-II):

(In Formula (D-II), R ⁷ is a monovalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, and X ¹ is a divalent organic group. is there.)
A compound represented by formula (D-III):

(In formula (D-III), R ⁸ is a divalent organic group, and X ² is a divalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine. A plurality of X ² may be the same or different.)
A compound represented by formula (D-IV):

(In the formula (D-IV), R ⁹ is a hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ⁹ may be the same or different, p is an integer of 1 to 3, q Is an integer from 1 to 20.)
And 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.)
The compound etc. which are represented by these can be mentioned.
Of these, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2, 2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 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-phenylenediisopropylidene) bisaniline 1,4-cyclohexanediamine, 4,4′-methylenebis (cyclohexylamine), 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, the above formula (9 ) To (13), 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′-di (4-aminophenyl) -benzidine, the above formula (D-II ) Represented by the following formula (D-6)

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

Of the compound represented by formula (D-1) or dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy- 2,5-diaminobenzene, dodecanoxy-2,5-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene and the following formula (D-8) ~ (D-13)

The compound represented by these is preferable.
The diamine used in producing the polyamic acid or imidized product thereof according to the present invention preferably contains a diamine having a steroid skeleton at least in part, and particularly in the above formula (DI), the group R ⁶ is a steroid. It is preferable that diamine which is group which has frame | skeleton is included.

<Polyamic acid>
The proportion of tetracarboxylic dianhydride and diamine compound used in the synthesis reaction of the polyamic acid that can be used in the present invention is tetracarboxylic dianhydride with respect to 1 equivalent of amino group contained in the diamine compound. The ratio in which the acid anhydride group is 0.2 to 2 equivalents is preferable, and the ratio is more preferably 0.3 to 1.2 equivalents.
The polyamic acid synthesis reaction is preferably performed in an organic solvent, preferably at a temperature of −20 to 150 ° C., more preferably at a temperature of 0 to 100 ° C., preferably 0.5 to 24 hours, more preferably 2 to 10 Done for hours. Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized polyamic acid. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, N, Aprotic polar solvents such as N-dimethylimidazolidinone, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide; and phenolic solvents such as m-cresol, xylenol, phenol, halogenated phenol Can do. The amount (a) of the organic solvent used is such that the total amount (b) of tetracarboxylic dianhydride and diamine compound is preferably 0.1 to 50% by weight, more preferably 5 to 5%, based on the total amount (a + b) of the reaction solution. The amount is 30% by weight.

The organic solvent can be used in combination with an alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbon, or the like, which is a poor solvent for polyamic acid, as long as the polyamic acid to be produced does not precipitate. Specific examples of such poor solvents include methanol, ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, and methyl ethyl ketone. , Methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether Ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether, Lenglycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4 -Dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, diisobutylketone, isoamylpropionate, isoamylisobutyrate, diisopentyl ether and the like.
When a polyamic acid is used in combination with a poor solvent as described above in the organic solvent, the use ratio can be appropriately set within the range where the produced polyamic acid does not precipitate, but preferably 50% by weight of the total solvent. % Or less.

  As described above, a reaction solution obtained by dissolving polyamic acid is obtained. Then, the reaction solution is poured into a large amount of a poor solvent to obtain a precipitate, and the precipitate is dried under reduced pressure, or the reaction solution is evaporated using a evaporator to obtain a polyamic acid. be able to. In addition, the polyamic acid can be purified by dissolving the polyamic acid in an organic solvent again and then precipitating with a poor solvent or depressurizingly distilling with an evaporator once or several times.

<Imidized product of polyamic acid>
The imidized product (polyimide) of polyamic acid that can be used in the present invention can be produced by dehydrating and ring-closing the amic acid structure of the polyamic acid as described above.
The polyamic acid is dehydrated and closed by (i) a method of heating the polyamic acid, or (ii) dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to this solution, and heating as necessary. By the method.
The reaction temperature in the method of heating the polyamic acid (i) is preferably 50 to 200 ° C, more preferably 60 to 170 ° C. When the reaction temperature is less than 50 ° C., the dehydration ring-closing reaction does not proceed sufficiently, and when the reaction temperature exceeds 200 ° C., the molecular weight of the resulting polyimide may decrease. The reaction time in the method of heating the polyamic acid is preferably 0.5 to 48 hours, more preferably 2 to 20 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. The amount of the dehydrating agent used is preferably 0.01 to 20 mol with respect to 1 mol of the amic acid structural unit. As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used. However, it is not limited to these. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. 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., and the reaction time is preferably 0.5 to 20 hours, more preferably 1 to 8 hours.
The polyimide can be isolated and purified by performing the same operation as the polyamic acid isolation and purification method on the reaction solution thus obtained.

The imidized product used in the present invention may have a low imidization ratio in which only a part of the amic acid structure is dehydrated and closed. The imidization rate of the imidized product used in the present invention is preferably 80% or more, more preferably 85% or more. Here, the “imidization ratio” is a ratio of the number of imide rings to the total number of amic acid units and imide rings in the polymer expressed in%. At this time, a part of the imide ring may be an isoimide ring.
The imidization rate can be obtained from the formula represented by the following formula (1) by dissolving the imidized product in an appropriate solvent, measuring ¹ H-NMR at room temperature using tetramethylsilane as a reference substance.

Imidation ratio (%) = (1-A ¹ / A ² × α) × 100 (1)

(In Formula (1), A ¹ is the peak area derived from protons of NH groups found at 10 ppm, A ² is the peak area derived from other protons, and α is the NH group in the polyamic acid before the dehydration ring closure reaction. The number ratio of other protons to one proton of

When using the polyimide obtained by using 2,3,5-tricarboxycyclopentyl acetic acid dianhydride having an exo body content of 90% or more and other tetracarboxylic acid dianhydrides in the liquid crystal aligning agent of the present invention, other As the tetracarboxylic dianhydride, other tetracarboxylic dianhydrides including alicyclic tetracarboxylic dianhydrides are preferable.
A particularly preferred alicyclic tetracarboxylic dianhydride in this case is 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-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2: 3 , 5: 6-dianhydride or 4, - a dioxatricyclo [5.3.1.0 ^{2, 6]} undecane -3,5,8,10- tetraone.

In the case of using a polyimide obtained using a tetracarboxylic dianhydride and a diamine containing 2,3,5-tricarboxycyclopentylacetic dianhydride having an exo body content of 90% or more in the liquid crystal aligning agent of the present invention. As the diamine, it is preferable to use a compound represented by the above formula (DI), and in particular, dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene. , Octadecanoxy-2,5-diaminobenzene, dodecanoxy-2,5-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene, the above formula (D -8) to (D-13) are preferred. There.
In this case, other diamines may be used in combination with the compound represented by the above formula (DI). Among the other diamines used here, for example, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2′-dimethyl are preferable. -4,4'-diaminobiphenyl, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 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, '-(M-phenylenediisopropylidene) bisaniline, 1,4-cyclohexanediamine, 4,4'-methylenebis (cyclohexylamine), 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis ( 4-aminophenoxy) biphenyl, compounds represented by the above formulas (D-1) to (D-3), 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6 -Diaminoacridine, N, N'-di (4-aminophenyl) -benzidine, a compound represented by the above formula (D-6) among the compounds represented by the above formula (D-II), the above formula (D Among the compounds represented by -III), the compounds represented by the above formula (D-7) can be exemplified.
When using a polyimide obtained by using tetracarboxylic dianhydride and diamine containing 2,3,5-tricarboxycyclopentylacetic acid dianhydride having an exo body content of 90% or more in the liquid crystal aligning agent of the present invention, Among the diamines used, the diamine represented by the above formula (D-I) is preferably 0.5% by weight or more, more preferably 1% by weight or more of the total diamine.

<Terminal-modified polyamic acid and imidized product thereof>
The polyamic acid or imidized product thereof may be a terminal-modified type having a controlled molecular weight. Such a terminal-modified type can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when synthesizing the polyamic acid. Examples of the acid monoanhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride, Examples thereof include n-hexadecyl succinic anhydride. 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 . Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.
<Solution viscosity of polyamic acid and imidized product>
The polyamic acid is a 10% by weight N-methyl-2-pyrrolidone solution, and the solution viscosity measured at 25 ° C. using an E-type rotational viscometer is preferably 20 to 800 mPa · s, and preferably 30 to 500 mPa · s. More preferably, it is s.
The imidized polyamic acid is a 10% by weight γ-butyrolactone solution, and the solution viscosity measured at 25 ° C. using an E-type rotational viscometer is preferably 20 to 800 mPa · s, and preferably 30 to 500 mPa · s. It is more preferable that

<Other ingredients>
Although the liquid crystal aligning agent of this invention contains at least 1 sort (s) chosen from the group which consists of said polyamic acid and its imidated substance as an essential component, it contains other components in the range which does not impair the effect of this invention besides this. can do. Examples of such other components include polymers other than the above polyamic acid and imidized products thereof (hereinafter referred to as “other polymers”) compounds having at least one epoxy group in the molecule, functional silane compounds, and the like. Can be mentioned.
Said other polymer can be used in order to improve the solution characteristic of the liquid crystal aligning agent of this invention, and the electrical property of the liquid crystal aligning film obtained. Examples of such other polymers include polyamic acids other than the above polyamic acids, imidized products thereof, polyamic acid esters, polyesters, polyamides, cellulose derivatives, polyacetals, polystyrene derivatives, poly (styrene-phenylmaleimide) derivatives, poly (meta ) Acrylate and the like.
When the liquid crystal aligning agent of the present invention contains another polymer, its use ratio is preferably 80% by weight or less, more preferably less than 50% by weight based on the total amount of the polymer. preferable.

The compound having at least one epoxy group in the molecule (hereinafter simply referred to as “epoxy compound”) can be used to improve the adhesion of the obtained liquid crystal alignment film to the substrate surface. As an epoxy compound, the compound which has 2 or more epoxy groups in a molecule | numerator is preferable, For example, the glycidyl ether of a polyalcohol, a glycidylamine compound, etc. can be mentioned.
Examples of the glycidyl ether of the polyalcohol 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, 1, 6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol and the like;
Examples of the glycidylamine compound include N, N, N ′, N′-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N, N-diglycidyl-benzylamine, N, N-diglycidyl-aminomethylcyclohexane and the like can be exemplified.
As the epoxy compound, a glycidylamine compound is preferable.
The use ratio of the epoxy compound 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.

Examples of the functional silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl) -3. -Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltri Methoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7- Riazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl- 3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene ) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, and the like.
The blending ratio of these functional silane compounds is preferably 40 parts by weight or less 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 comprises at least one selected from the group consisting of the above polyamic acid and imidized product thereof and other components optionally added, preferably dissolved in an organic solvent. .
As an organic solvent which comprises 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. Moreover, the poor solvent illustrated as what can be used together in the case of the synthesis reaction of a polyamic acid can also be selected suitably, and can be used together.
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 of the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is selected in consideration of viscosity, volatility, and the like. . Preferably it is the range of 1-10 weight%. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface to form a coating film that becomes a liquid crystal aligning film. When the solid content concentration is less than 1% by weight, the film thickness of this coating film is When the solid content concentration exceeds 10% by weight, it is difficult to obtain a good liquid crystal alignment film because the film thickness is excessive. The viscosity of the aligning agent increases, resulting in poor coating properties.
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 solid content concentration is particularly preferably in the range of 1.5 to 4.5% by weight. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the ink jet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s.
The temperature at which the liquid crystal aligning agent of the present invention is prepared is preferably 0 ° C to 200 ° C, more preferably 20 ° C to 60 ° C.

  Particularly preferred organic solvents 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 di Examples include methyl ether, diethylene 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.

<Liquid crystal display element>
The liquid crystal display element obtained using the liquid crystal aligning agent of this invention can be manufactured, for example with the following method.
(1) The liquid crystal aligning agent of the present invention is applied to one surface of a substrate provided with a patterned transparent conductive film by a method such as a roll coater method, a spinner method, a printing method, an ink jet method, etc. Is heated to form a coating film. Here, as the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, polyalicyclic olefin, or the like can be used. As the transparent conductive film provided on one surface of the substrate, a 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. Can be used. For patterning these transparent conductive films, a photo-etching method or a method using a mask in advance is 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-containing compound, a functional titanium-containing compound, or the like is previously applied to the surface of the substrate. You may keep it.
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 300 ° C, more preferably 40 to 200 ° C, and particularly preferably 50 to 150 ° C. Thereafter, a baking (post-baking) step is performed for the purpose of completely removing the solvent. The firing (post-bake) temperature is preferably 80 to 300 ° C, more preferably 120 to 250 ° C.
In this way, the liquid crystal aligning agent of the present invention forms a coating film that becomes a liquid crystal aligning film by removing the organic solvent after coating, but the liquid crystal aligning agent of the present invention contains a polymer having an amic acid structure. The film can be further heated to cause dehydration ring closure to proceed to a more imidized coating film. The film thickness of the formed coating film is preferably 0.001-1 μm, more preferably 0.005-0.5 μm.

(2) Next, a rubbing process is performed in which the coating film surface formed as described above is rubbed in a fixed direction with a roll wound with a cloth made of fibers such as nylon, rayon, and cotton. Thereby, the orientation ability of a liquid crystal molecule is provided to a coating film, and it becomes a liquid crystal aligning film.
Further, the liquid crystal alignment film formed by the liquid crystal aligning agent of the present invention is disclosed in, for example, Patent Document 6 (Japanese Patent Laid-Open No. 6-222366) or Patent Document 7 (Japanese Patent Laid-Open No. 6-281937). The surface of the liquid crystal alignment film subjected to a rubbing treatment as shown in Patent Document 8 (JP-A-5-107544) or a treatment that changes the pretilt angle by partially irradiating ultraviolet rays. By forming a resist film partially and performing rubbing treatment in a direction different from the previous rubbing treatment, removing the resist film and changing the liquid crystal aligning ability of the liquid crystal alignment film, liquid crystal display It is possible to improve the visibility characteristics of the element.
(3) Two substrates on which the liquid crystal alignment film is formed as described above are manufactured, and the two substrates are separated by a gap (cell gap) so that the rubbing directions in the respective liquid crystal alignment films are orthogonal or antiparallel. ), And the periphery of the two substrates are bonded together using a sealant, and liquid crystal is injected and filled in the cell gap defined by the substrate surface and the sealant, and the injection hole is sealed. A liquid crystal cell is constructed. And a liquid crystal display element is obtained by arrange | positioning a polarizing plate to the outer surface of a liquid crystal cell, ie, the transparent substrate side which comprises 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.
Examples of the liquid crystal include nematic liquid crystal and smectic liquid crystal. Among them, nematic liquid crystal is preferable. For example, Schiff base liquid crystal, azoxy liquid crystal, biphenyl liquid crystal, phenyl cyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal. Liquid crystals, biphenylcyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, cubane liquid crystals, and the like can be used. In addition, 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” (manufactured by Merck) A ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate may be further added.
As a polarizing plate bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film in which a polarizing film called an “H film” that absorbs iodine while stretching and aligning polyvinyl alcohol is sandwiched between protective films of cellulose acetate 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. In the examples and comparative examples, the imidization ratio of the imidized polymer, the voltage holding ratio, and the coating property of the liquid crystal alignment agent were evaluated by the following methods.
[Imidation rate]
The imidization rate was determined by drying an imidized product (imidized polymer) under reduced pressure at room temperature, dissolving it in deuterated dimethyl sulfoxide, measuring ¹ H-NMR at room temperature using tetramethylsilane as a reference substance, Obtained by 1).
[Solution viscosity]
The solution viscosity of the polymer is 10% by weight N-methyl-2-pyrrolidone solution in the case of polyamic acid, and 10% by weight γ-butyrolactone solution in the case of imidized polymer. It measured at 25 degreeC using the E-type rotational viscometer.
[Voltage holding ratio]
A voltage of 5 V was applied to the liquid crystal display element 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. The measuring apparatus used was VHR-1 manufactured by Toyo Corporation. When the voltage holding ratio was 95% or more, it was judged as “good”.

<Synthesis of exo-2,3,5-tricarboxycyclopentylacetic acid dianhydride>
Synthesis example 1
(1) Synthesis of hydroxy-dicyclopentadiene 153 g of water and 72 g of 78% sulfuric acid were added to a 3 liter three-necked flask and heated to 60 ° C. Dicyclopentadiene 76g was added here, and it reacted at 100 degreeC for 6 hours, stirring violently. The reaction mixture was cooled to room temperature and allowed to stand until the layers were separated. The organic layer was taken, 76 g of toluene was added thereto and heated to 55 ° C., 76 g of water, 7.6 g of sodium bicarbonate and 7.6 g of sodium chloride were added, and stirring was further continued at 55 ° C. for 30 minutes. The organic layer was taken by standing until the layers were separated again, and concentrated under reduced pressure to remove toluene. 40 g of water was added to the residue, heated to 75 ° C., further heated to 100 ° C., and toluene and water were removed azeotropically by distillation under reduced pressure to obtain 78 g of a crude product of hydroxy-dicyclopentadiene.
With respect to 78 g of this parent product, 60 g of purified hydroxy-dicyclopentadiene was obtained by distillation under reduced pressure while maintaining the temperature at 150 ° C. or lower.
(2) Oxidation of hydroxy-dicyclopentadiene 67.5% nitric acid and ammonium vanadate were added to a 3 liter flask and heated to 43 ° C. 54 g of hydroxydicyclopentadiene synthesized above was added dropwise thereto. At this time, the temperature of the reaction solution during dropping was maintained at 42 to 45 ° C. After completion of the dropping, the reaction was carried out at 43 ° C. for 2 hours, and the reaction was further continued at 48 ° C. for 8 hours. About 108 g of the solution remaining after concentration under reduced pressure at 62 ° C., the reaction was further performed at 50 ° C. for 8 hours. The reaction mixture was cooled to 10 ° C. and allowed to crystallize over 1 hour. 67.5% nitric acid was added to the slurry containing crystals, and the crystals were collected by filtration. The crystals collected on the filter were dried under reduced pressure together with the filter to obtain about 46 g of crude crystals containing 2,3,5-tricarboxycyclopentylacetic acid. Add 16 g of ultrapure water to the filter and stir at 60 ° C. to dissolve the crystals remaining in the filter (crystals that cannot be recovered and remain on the filter), and then add an aqueous solution containing 2,3,5-tricarboxycyclopentylacetic acid. It was collected.

(3) Acid precipitation of 2,3,5-tricarboxycyclopentylacetic acid 46 g of the crude crystal containing 2,3,5-tricarboxycyclopentylacetic acid obtained above and the recovered 2,3,5-tricarboxycyclopentylacetic acid crude crystal 5.8 g of ultrapure water was added to the aqueous solution containing, and stirred at 75 ° C. to dissolve the crystals. To this solution, 51.4 g of 35% hydrochloric acid was added dropwise over 30 minutes while maintaining the internal temperature of the reactor at 75 ° C. After completion of the dropwise addition, the reaction was continued at 75 ° C. for 2 hours. The reaction mixture was then cooled to −3 ° C. and left for 10 hours to precipitate crystals. The supernatant was discarded, the remaining slurry was transferred to a centrifugal filtration device, and 24 g of methyl isobutyl ketone was added. The solid is separated from the supernatant by centrifugation, the supernatant is discarded, the slurry containing the crystals is recovered, transferred to a centrifugal filter again, the same operation as above is repeated twice, and the resulting crystals are extracted with methyl isobutyl ketone. Washed.
Thus, a methyl isobutyl ketone slurry containing 38 g of acidified 2,3,5-tricarboxycyclopentylacetic acid was obtained.

(4) Dehydration of 2,3,5-tricarboxycyclopentylacetic acid 118 g of acetic anhydride was charged into a 2 liter flask under a nitrogen atmosphere, and then the purified 2,3,5-tricarboxycyclopentylacetic acid obtained above was 33 g of crystals were added. The mixture was heated to 90 ° C. and reacted under nitrogen for 3 hours. The internal temperature of the reactor was once cooled to 45 ° C., and the internal temperature was kept below 60 ° C., followed by concentration under reduced pressure, and about 100 ml of the effluent was discarded. Further, 20 g of acetic anhydride was added under the condition of the internal temperature of 60 ° C. or less, and the solution was further concentrated under reduced pressure under the condition of the internal temperature of 60 ° C. or less, and about 18 ml of the distillate was discarded. Under nitrogen gas flow, the reaction mixture was cooled to 7 ° C. with stirring, and stirred at this temperature for 10 hours to ripen the crystals. Next, the slurry containing the crystals was pressure filtered with nitrogen gas to obtain crude crystals.
Next, the above crude crystals and 67 g of methyl isobutyl ketone cooled to -5 ° C. were put into a 2 liter flask cooled to −5 ° C. filled with dry nitrogen. Under a nitrogen stream, the slurry was stirred at an internal temperature of 5 ° C. for 2 hours. The slurry was filtered under nitrogen pressure, and the resulting solid was washed with 12 g of methyl isobutyl ketone. The solid matter inside the filter was dried under reduced pressure at 60 ° C. together with the filter. The inside of the dryer was replaced with argon gas, and 22 g of crystals were collected from the filter under the flow of argon gas.
Next, the discharge port of the filter was closed, 332 g of acetone was added to the filter, and the mixture was heated to 30 ° C. to dissolve the crystals remaining in the filter. Acetone (20 g) and the previously recovered crystal (22 g) were added to the filter, and a condenser was attached to the filter to heat the inside to 55 ° C. After the solid matter was dissolved under reflux, the temperature inside the filter was adjusted to 50 ° C. The outlet at the bottom of the filter was opened and filtered, and 12 g of acetone was further added to the filter to flush the inside of the filter. The filtrate and flushing liquid were transferred to a 2 liter flask and heated to 60 ° C. to distill off about 350 g of acetone. Thereafter, the temperature in the flask was cooled to −3 ° C. under a nitrogen gas flow, and aged for 10 hours at this temperature to precipitate crystals. The obtained slurry was transferred to a pre-cooled filter, pressure filtered under nitrogen, and 16 g of acetone cooled to 0 ° C. was added to wash the crystals. The crystal remaining in the filter was dried under reduced pressure at 40 ° C. together with the filter. From the filter, 18 g of 2,3,5-tricarboxycyclopentylacetic acid dianhydride crystals were recovered.

(4) Analysis of 2,3,5-tricarboxycyclopentylacetic acid dianhydride ¹ H-NMR and ¹³ C-NMR were measured for the crystals of 2,3,5-tricarboxycyclopentylacetic acid dianhydride obtained above. As a result, the exo content was about 100%. ¹ H-NMR chart and ¹³ C-NMR chart are shown in FIGS. 1 and 2, respectively. Moreover, the attribution of each spectrum specified by the result of the spectrum measurement of two-dimensional NMR (HH-COSY, HH-NOESY, HMBC, HMQC) is shown below.

<Synthesis of imidized polymer>
Synthesis example 2
110 g (0.50 mol) of exo-2,3,5-tricarboxycyclopentylacetic acid dianhydride (hereinafter referred to as “exo-TCA-AH”) obtained in Synthesis Example 1 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 160 g (0.50 mol), 95 g (0.88 mol) of p-phenylenediamine as a diamine, 32 g (0.10 mol) of 2,2-ditrifluoromethyl-4,4-diaminobiphenyl, 3,6-bis ( 4-Aminobenzoyloxy) cholestane (compound represented by the above formula (D-1)) 6.4 g (0.010 mol) and octadecanoxy-2,5-diaminobenzene 4.0 The (0.015 mol) was dissolved in N- methyl-2-pyrrolidone 960 g, it was 9 hours at 60 ° C., to obtain a polyamic acid solution. A small amount of the resulting polyamic acid solution was taken and the solution viscosity of the polymer was measured. The solution viscosity was 58 mPa · s.
To the obtained polyamic acid solution, 2,740 g of N-methyl-2-pyrrolidone, 396 g of pyridine and 409 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the reaction, the solvent in the system was replaced with a new γ-butyrolactone (the pyridine and acetic anhydride used for the imidization reaction were removed from the system by this operation), the solid content concentration was 15% by weight, and the imidization rate. About 2,400 g of a solution of about 94% imidized polymer (referred to as “imidized polymer (A-1)”) was obtained.
The solution viscosity of this imidized polymer (A-1) was 69 mPa · s.

Synthesis example 3
112 g (0.50 mol) of exo-TCA-AH 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 157 g (0.50 mol), p-phenylenediamine 96 g (0.89 mol) as diamine, bisaminopropyltetramethyldisiloxane 25 g (0 .10 mol) and 3,6-bis (4-aminobenzoyloxy) cholestane 13 g (0.020 mol) and N-octadecylamine 8.1 g (0.030 mol) as monoamine are added to 960 g of N-methyl-2-pyrrolidone. And reacted at 60 ° C. for 6 hours to obtain a polyamic acid solution. A small amount of the resulting polyamic acid solution was taken and the solution viscosity of the polymer was measured, and it was 60 mPa · s.
Next, 2,700 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 396 g of pyridine and 409 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the reaction, the solvent in the system was replaced with a new γ-butyrolactone (the pyridine and acetic anhydride used for the imidization reaction were removed from the system by this operation), the solid content concentration was 15% by weight, and the imidization rate. About 1,900 g of a solution of about 95% imidized polymer (referred to as “imidized polymer (A-2)”) was obtained.
The solution viscosity of this imidized polymer (A-2) was 77 mPa · s.

Synthesis example 4
112 g (0.50 mol) of exo-TCA-AH as a tetracarboxylic dianhydride, 43 g (0.40 mol) of p-phenylenediamine as a diamine compound and 52 g (0. 3 of 3,3,3-diaminobenzoyloxy) cholestane. 10 mol) was dissolved in 830 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours to obtain a polyamic acid solution. A small amount of the resulting polyamic acid solution was taken and the solution viscosity of the polymer was measured, and it was 2,100 mPa · s. Next, 1,900 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 40 g of pyridine and 51 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone (pyridine and acetic anhydride used in the imidization reaction were removed from the system in this operation), and the solid content concentration was 15% by weight. Thus, about 1,400 g of an imidized polymer having an imidization ratio of about 50% (hereinafter referred to as “imidized polymer (A-3)”) was obtained.
Synthesis example 5
112 g (0.50 mol) of exo-TCA-AH as a tetracarboxylic dianhydride, 49 g (0.45 mol) of p-phenylenediamine as a diamine compound, and 26 g (0. 3 of 3,3,5-diaminobenzoyloxy) cholestane. 05 mol) was dissolved in 750 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours to obtain a polyamic acid solution. A small amount of the resulting polyamic acid solution was sampled and the solution viscosity of the polymer was measured, and it was 2,000 mPa · s.
Next, 1,800 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 40 g of pyridine and 51 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone (pyridine and acetic anhydride used in the imidization reaction were removed from the system in this operation), and the solid content concentration was 15% by weight. About 1,500 g of an imidized polymer having an imidization ratio of about 50% (hereinafter referred to as “imidized polymer (A-4)”) was obtained.

Synthesis Example 6
112 g (0.50 mol) of exo-TCA-AH as tetracarboxylic dianhydride, 38 g (0.35 mol) of p-phenylenediamine as a diamine compound, 20 g (0.1 mol) of 4,4′-diaminodiphenylmethane and A solution of polyamic acid was obtained by dissolving 26 g (0.05 mol) of 3 (3,5-diaminobenzoyloxy) cholestane in 750 g of N-methyl-2-pyrrolidone and reacting at 60 ° C. for 6 hours. . A small amount of the resulting polyamic acid solution was sampled and the solution viscosity of the polymer was measured, and it was 2,000 mPa · s.
Next, 1,800 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 40 g of pyridine and 51 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone (pyridine and acetic anhydride used in the imidization reaction were removed from the system in this operation), and the solid content concentration was 15% by weight. About 1,500 g of a solution of an imidized polymer having an imidization ratio of about 50% (hereinafter referred to as “imidized polymer (A-5)”) was obtained.
<Synthesis of polyamic acid>
Synthesis example 7
1,2,3,4-cyclobutanetetracarboxylic dianhydride 98 g (0.50 mol) and pyromellitic dianhydride 109 g (0.50 mol) as tetracarboxylic dianhydride and 4,4 as diamine compound 198 g (1.0 mol) of '-diaminodiphenylmethane was dissolved in a mixed solvent consisting of 230 g of N-methyl-2-pyrrolidone and 2,060 g of γ-butyrolactone, reacted at 40 ° C. for 3 hours, and then γ-butyrolactone 1 350 g were added to obtain about 3,600 g of a polyamic acid solution having a solid content concentration of 10% by weight (hereinafter referred to as polyamic acid (B-1)).
The solution viscosity of this polyamic acid (B-1) was 125 mPa · s.
Synthesis example 8
196 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 212 g (1 of 2,2′-dimethyl-4,4′-diaminobiphenyl as diamine compound) 0.0 mol) is dissolved in a mixed solvent composed of 370 g of N-methyl-2-pyrrolidone and 3,300 g of γ-butyrolactone, and reacted at 40 ° C. for 3 hours to obtain a polyamic acid having a solid content concentration of 10% by weight (this) To about 3,700 g of a polyamic acid (B-2) solution.
The solution viscosity of this polyamic acid (B-2) was 160 mPa · s.

Example 1
The imidized polymer (A-1) obtained in Synthesis Example 2 and the polyamic acid (B-1), γ-butyrolactone, N-methyl-2-pyrrolidone and butyl cellosolve obtained in Synthesis Example 7 -1): (B-1) = 20: 80 (weight ratio) and the solvent composition is γ-butyrolactone: N-methyl-2-pyrrolidone: butyl cellosolve = 71: 17: 12 (weight ratio) Further, 5 parts by weight of N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane is added to 100 parts by weight of the total amount of the polymer, and the solid content concentration is 3.5% by weight. It was set as the solution. This solution was sufficiently stirred and then filtered using a filter having a pore size of 1 μm to prepare a liquid crystal aligning agent.
This liquid crystal aligning agent is applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a liquid crystal alignment film printer (Nissha Printing Co., Ltd.) and heated on a hot plate at 80 ° C. for 1 minute. Then, it heated for 10 minutes on a 200 degreeC hotplate, and formed the coating film with an average film thickness of 1,000 angstroms. When this coating film was observed with a microscope having a magnification of 20 times, printing unevenness and pinholes were not observed, and the printability was good.
Next, using a rubbing machine having a roll in which a nylon cloth is wrapped around this coating film, a rubbing treatment is performed at a roll rotation speed of 500 rpm, a stage moving speed of 3 cm / second, and a hair foot indentation length of 0.4 mm, and a liquid crystal alignment film is formed. Formed.
By repeating the same operation as described above, two substrates (one pair) having a liquid crystal alignment film were prepared.
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 pair of liquid crystal alignment films, the liquid crystal alignment film surfaces are stacked and pressure-bonded so as to face each other. Cured. Next, a liquid crystal display element is manufactured by filling a nematic liquid crystal (MLC-6221, manufactured by Merck & Co., Inc.) into the gap between the liquid crystal inlet and the liquid crystal inlet with an acrylic photo-curing adhesive. did.
When the obtained liquid crystal display element was applied with a rectangular wave of 30 Hz and 3.0 V with an alternating current of 6.0 V (peak-peak) superimposed at an ambient temperature of 70 ° C. for 500 hours, the element was visually observed. There was no display defect of the element.
Moreover, the voltage holding property of this liquid crystal display element was good.

Example 2
A liquid crystal aligning agent was prepared in the same manner as in Example 1 except that the imidized polymer (A-2) obtained in Synthesis Example 3 was used instead of the imidized polymer (A-1), and the substrate A coating film was formed on the surface. When this coating film was observed in the same manner as in Example 1, no printing unevenness and pinholes were observed, and the printability was good. Further, when a liquid crystal display element was manufactured using the substrate on which the liquid crystal alignment film was formed and observed in the same manner as in Example 1, no display defect was found. This liquid crystal display element had good voltage holding properties.
Examples 3-4
A coating film was formed on the substrate surface in the same manner as in Example 1 or 2 except that the polyamic acid (B-2) obtained in Synthesis Example 8 was used instead of the polyamic acid (B-1). . When this coating film was observed in the same manner as in Example 1, neither printing unevenness nor pinhole was observed, and the printability was good. Further, when a liquid crystal display element was produced using the substrate on which the liquid crystal alignment film was formed and observed in the same manner as in Example 1, no display defect was observed in any case. These liquid crystal display elements had good voltage holding properties.

Example 5
100 parts by weight (solid content) of the imidized polymer (A-3) obtained in Synthesis Example 4 and 0.2 part by weight of N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane Was dissolved in a mixed solvent of N-methyl-2-pyrrolidone and butyl cellosolve so that the solvent composition was N-methyl-2-pyrrolidone: butyl cellosolve = 50: 50 (weight ratio), and the solid content concentration was 4% by weight. A liquid crystal aligning agent was prepared by preparing a solution and filtering the solution using a filter having a pore size of 1 μm.
When a coating film was formed on the substrate surface in the same manner as in Example 1 using the above liquid crystal aligning agent and observed, printing unevenness and pinholes were not seen in the coating film, and the printability was good. In addition, a liquid crystal display element was manufactured and observed in the same manner as in Example 1 except that nematic liquid crystal (MLC-6601, manufactured by Merck & Co., Inc.) was used as the liquid crystal, and no display defect was observed. This liquid crystal display element had good voltage holding properties.
Examples 6-7
Instead of the imidized polymer (A-3), the imidized polymer (A-4) or (A-5) obtained in Synthesis Examples 5-6 was used in the same manner as in Example 5, When a coating film was formed on the surface of the substrate and observed, printing unevenness and pinholes were not observed, and the printability was good. In addition, when a liquid crystal display element was produced using the substrate on which the liquid crystal alignment film was formed and observed in the same manner as in Example 5, no display defect was observed. These liquid crystal display elements had good voltage holding properties.

  As is clear from the above examples, the liquid crystal aligning agent of the present invention is excellent in liquid crystal aligning properties and electrical characteristics, and has improved coatability. The reason why the liquid crystal aligning agent of the present invention exerts such advantageous effects is not yet clear, but by making the steric structure of 2,3,5-tricarboxycyclopentylacetic acid dianhydride uniform, polyamic acid or imidized product thereof This is presumably due to the fact that the twist of the molecular chain became uniform, and this improved the solubility of the polymer.

¹ H-NMR chart (all region diagram) of exo-2,3,5-tricarboxycyclopentylacetic acid dianhydride obtained in Synthesis Example 1. ¹ H-NMR chart (partially enlarged view) of exo-2,3,5-tricarboxycyclopentylacetic acid dianhydride obtained in Synthesis Example 1. ¹³ C-NMR chart (high chemical shift region) of exo-2,3,5-tricarboxycyclopentylacetic acid dianhydride obtained in Synthesis Example 1. FIG. ¹³ C-NMR chart (low chemical shift region) of exo-2,3,5-tricarboxycyclopentylacetic acid dianhydride obtained in Synthesis Example 1. FIG.

Claims (7)

At least one heavy selected from the group consisting of a polyamic acid obtained by reaction of a tetracarboxylic dianhydride including 2,3,5-tricarboxycyclopentylacetic dianhydride with a diamine and an imidized product of the polyamic acid. A liquid crystal aligning agent containing a coalescence,
The liquid crystal aligning agent characterized by the exo body content of the said 2,3,5-tricarboxycyclopentyl acetic acid dianhydride being 90% or more.   The liquid crystal aligning agent of Claim 1 whose diamine contains the diamine which has steroid skeleton. Diamine is represented by the following formula (D-I)
(In the formula (DI), R ⁵ is a divalent group selected from —O—, —COO—, —OCO—, —NHCO—, —CONH— and —CO—, and one R ⁶ is A monovalent hydrocarbon group having 1 to 40 carbon atoms which may contain the above unsaturated bond, provided that part or all of the hydrogen atoms of the monovalent hydrocarbon group are substituted by fluorine atoms. May be.)
The liquid crystal aligning agent of Claim 1 containing the compound represented by these. (D-I) group R ⁶ in the formula is a group having a steroid skeleton, a liquid crystal aligning agent of claim 3.   Furthermore, the liquid crystal aligning agent as described in any one of Claims 1-4 containing the compound containing 2 or more epoxy groups in a molecule | numerator.   The liquid crystal aligning agent of Claim 5 whose compound which contains a 2 or more epoxy group in a molecule | numerator is a glycidylamine compound.   A liquid crystal display element comprising a liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 6.