JP2005283859A - Evaluation method of polymer for liquid crystal alignment agent, and liquid crystal alignment agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for discriminating a liquid crystal alignment agent having coating defect generating possibility before the liquid crystal alignment agent is applied and to provide the liquid crystal alignment agent causing no coating defect using the same. <P>SOLUTION: In an evaluation method of an organic macromolecular polymer solution, printing properties when the organic macromolecular polymer solution is used as a liquid crystal alignment agent are evaluated by measuring dynamic light scattering of the organic macromolecular polymer solution and obtaining the maximum size or the position of a peak top of a flocculation body originating from an organic macromolecular polymer component from the measured dynamic light scattering. The liquid crystal alignment agent has ≤20 μm peak top hydrodynamic radius (R<SB>H</SB>) of the maximum peak or an average value thereof of a flocculation body originating from the organic macromolecular polymer component. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for evaluating a liquid crystal aligning agent, and a liquid crystal aligning agent that is evaluated by using this evaluation method and hardly causes poor coating during flexographic printing.

  At present, a liquid crystal alignment film made of an organic polymer or the like 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. A so-called TFT liquid crystal panel in which layers are formed to form a sandwich cell and this liquid crystal display element is operated by TFT driving is becoming widespread in place of a conventional cathode ray tube monitor. As the liquid crystal display element, nematic liquid crystal having positive dielectric anisotropy is used as the liquid crystal, and the major axis of the liquid crystal molecules is continuously twisted by 90 degrees from one substrate to the other substrate. A TN liquid crystal display element having a TN (Twisted Nematic) type liquid crystal cell is known. Further, STN (Super Twisted Nematic) type liquid crystal display elements and vertical alignment type liquid crystal display elements, which have a higher contrast than the TN type liquid crystal display elements and have less viewing angle dependency, have been developed. This STN type liquid crystal display element uses nematic liquid crystal blended with a chiral agent which is an optically active substance as liquid crystal, and the major axis of liquid crystal molecules is continuously twisted over 180 degrees between substrates. The birefringence effect generated by the above is utilized. In addition, an IPS (In-Plane Switching) type liquid crystal display element and a vertical alignment type liquid crystal display element, which have less viewing angle dependency than a TN type liquid crystal display element, have been developed. The liquid crystal alignment film has a function of controlling the alignment of the liquid crystal in these liquid crystal display elements, and a liquid crystal alignment material composed of an organic polymer or the like and a liquid crystal alignment agent including a solvent are applied to the substrate by a flexographic printing method or the like. Then, it is baked to form a resin film, which is obtained by imparting liquid crystal alignment ability. Examples of the organic polymer used as the liquid crystal alignment film material include an imidized polymer of polyamic acid as described in Patent Document 1 and Patent Document 2, a polyamic acid as described in Patent Document 3, and Patent Document A mixture of polyamic acid and / or imidized polymer as described in No. 4 and partially imidized polymer as described in Patent Document 5 are used.

  For forming the liquid crystal alignment film, a flexographic printing method capable of forming a film with a small amount of coating liquid is widely used. However, the organic polymer used as the alignment film material has a composition distribution of a chemical structure and a molecular weight distribution in one polymer chain. Due to the influence, there was a problem that a pinhole-like defect or the like was generated during flexographic printing. The pinhole defect portion causes a display defect such as a bright spot because the alignment state of the liquid crystal molecules is different from the surrounding when the liquid crystal display element is driven.

  As a liquid crystal aligning agent that hardly causes poor coating, Patent Document 6 discloses a liquid crystal aligning agent containing an auxiliary component selected from a homopolymer and a copolymer of an acrylate ester and a methacrylate ester. Patent Document 7 discloses a liquid crystal aligning agent derived from a specific component and made of a mixture of polyamic acids having a reduced viscosity within a certain range. In addition, as a substrate processing method in which defective coating is unlikely to occur, Patent Document 8 discloses a method of cleaning a substrate before forming an alignment film with an alkaline aqueous solution. Patent Document 9 discloses a method of maintaining a clean state by performing a cleaning process on a substrate surface and then immersing it in a storage solution. Patent Document 10 discloses a method for improving the wettability of a liquid crystal aligning agent by irradiating a substrate surface with ultraviolet rays. Patent Document 11 discloses a method for preventing coating failure by managing the anion intensity after cleaning the substrate to be a certain concentration or less. Patent Document 12 discloses a method in which a substrate is subjected to glow discharge treatment to decompose attached impurities and make it difficult to cause poor coating.

However, as described in Patent Document 6 and Patent Document 7, the alignment film design whose main purpose is to prevent the occurrence of defective coating is compatible with the expression of the intended liquid crystal panel display characteristics of the alignment film. It is difficult to do and narrows the choice of materials that can be used. In addition, performing the substrate processing as described in Patent Document 8, Patent Document 9, Patent Document 10, Patent Document 11 and Patent Document 12 in the liquid crystal panel manufacturing process increases the number of necessary processes. As a result, the manufacturing cost is increased.
Japanese Patent Laid-Open No. 05-60565 Japanese Patent No. 2893671 Japanese Patent No. 2600368 JP-A-10-183120 JP 05-216044 A JP-A-6-256716 JP 2002-88241 A JP-A-6-186564 JP 2001-300454 A JP 2002-196337 A JP 2002-355621 A JP 2003-140155 A

  From the above situation, an object of the present invention is to provide a liquid crystal aligning agent that can be used regardless of the material type of the liquid crystal aligning agent and that does not necessarily cause a coating failure without necessarily performing a special substrate surface treatment.

  Another object of the present invention is to provide a liquid crystal aligning agent evaluation method for discriminating in advance a liquid crystal aligning agent that may cause poor coating.

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

  According to the present invention, the above-described objects and advantages of the present invention are as follows. First, the dynamic light scattering of the organic polymer solution is measured, and from the measured dynamic light scattering, the organic polymer component is derived. An organic polymer solution, characterized in that the maximum size of the aggregate or the position of the peak top is determined, thereby evaluating the printability when the organic polymer solution is used as a liquid crystal aligning agent. Achieved by the evaluation method.

According to the present invention, the above-mentioned objects and advantages of the present invention are, secondly, the maximum peak of the aggregate derived from the organic polymer component as measured in the dynamic light scattering measurement of the organic polymer solution. The peak top hydrodynamic radius (R _H ) or the average value of the maximum peak hydrodynamic radius (R _H ) is 20 μm or less. However, this is achieved by a liquid crystal aligning agent comprising an organic polymer polymer solution, characterized in that when a plurality of organic polymer polymers are contained, at least one of them satisfies the above relationship.

Furthermore, according to the present invention, the above-mentioned objects and advantages of the present invention are thirdly based on the fact that the aggregate derived from the organic polymer component is measured in the dynamic light scattering measurement of the organic polymer solution. The peak peak hydrodynamic radius (R _H ) of the maximum peak or the average value of the hydrodynamic radius (R _H ) of the maximum peak is 20 μm or less, and the z-average fraction of the maximum peak is 0.20 or less. . However, when a plurality of organic polymer polymers are contained, at least one of them satisfies the above relationship, and this is achieved by a liquid crystal aligning agent comprising an organic polymer solution.

The evaluation method of the present invention measures the dynamic light scattering of an organic polymer solution, and the peak top hydrodynamic radius (R _H ) of the largest aggregate due to the association of the polymer at a defined concentration of the solution, Alternatively, the printability of the liquid crystal aligning agent is evaluated by the average value of the hydrodynamic radius (R _H ) of the maximum peak. Here, the printability means a state in which there are no pinhole defects that may be recognized during flexographic printing. Here, the average value of the hydrodynamic radius (R _H ) of the peak top and the hydrodynamic radius (R _H ) of the maximum peak is almost the same when the R _H distribution is symmetrical. In the case of left-right asymmetry, different values may be taken. The larger the aggregate size, the more likely to cause pinhole defects. Therefore, in the present invention, the larger hydrodynamic radius (R _H ) is specified as a parameter.

In the polymer solution, the polymer performs a diffusion motion due to the thermal motion, and as a result, concentration fluctuation occurs. In dynamic light scattering (DLS), the diffusion coefficient of a polymer can be measured by calculating the self-time correlation function of scattered light intensity fluctuation, that is, concentration fluctuation, obtained from a polymer solution irradiated with a laser beam. it can. The diffusion coefficient at the finite concentration obtained here is related to the hydrodynamic radius (R _H ) at the finite concentration by the Einstein-Stokes equation. The hydrodynamic radius (R _H ) corresponds to the radius when the extension of the polymer chain in a finite concentration solution is represented by a virtual hard sphere.

In a polymer solution, the diffusion coefficient obtained from the self-time correlation function of concentration fluctuation, that is, the hydrodynamic radius (R _H ) is one value as a result of the influence of molecular weight distribution, association of molecular chains, formation of network structure, etc. It is rare to be specified, and generally has a certain distribution width. In order to obtain the diffusion coefficient, that is, the distribution of the hydrodynamic radius (R _H ) from the self-time correlation function of the concentration fluctuation, there are several analysis methods. For example, cumulant analysis is performed on a polymer solution having a relatively narrow diffusion coefficient distribution. In this method, a diffusion coefficient as an average value and a parameter representing the distribution width are obtained. On the other hand, in a system in which molecular chains are associated with each other in a solution, the distribution is often very wide. In this case, analysis by a histogram method, a CONTIN method, or the like is performed. In the histogram method and CONTIN method, the diffusion coefficient, that is, the z-average fraction of the hydrodynamic radius (R _H ) distribution is obtained.

In general, the diffusion coefficient, that is, the average value and distribution shape of the hydrodynamic radius (R _H ) vary depending on the polymer concentration in the solution. Since it is the liquid crystal alignment agent of the concentration at the time of changes in the concentration of the solution as a product it is assumed that the concentration changes when printed on a substrate, hydrodynamic radius obtained at a finite concentration (R _H) after printing It indirectly represents the aggregate size of the polymer components produced in the film. In many polymer solutions for alignment films, when the concentration is about 1% by weight or less, each molecular chain is dissolved as a single chain. However, as the concentration increases, the association between the molecular chains proceeds and aggregates are formed due to the poor solubility of the polymer in the solvent. In the worst case, extremely large aggregates of several tens of μm are formed, the printability is extremely deteriorated, and pinhole-like defects may be formed during alignment film printing on the substrate.

By obtaining the z-average distribution of the hydrodynamic radius (R _H ) using DLS measurement and CONTIN analysis, the aggregate size and z-average fraction in the alignment layer polymer solution can be obtained as numerical values. it can. Variations in the hydrodynamic radius distribution of the polymer component agglomerates are reflected in variations in the thickness of the alignment film printed on the substrate, which may lead to pinhole defects that occur when the alignment film is not applied. It was found. For this reason, it was found that by using DLS, the z-average distribution of the hydrodynamic radius (R _H ) was measured, and the product and the polymer solution for the alignment agent could be evaluated and selected at the raw material stage. The present invention is based on such knowledge.

The polymer solution for an alignment film of the present invention is a composition containing an organic polymer and a solvent, and the polymer solution has a solid content concentration of 1 to 10% by weight. by dynamic light scattering measurements, hydrodynamic radius representing the aggregate size in the solution of the alignment film resin at a defined concentration of the solution (R _H) peak top hydrodynamic radius at the maximum peak of the (R _H), or the maximum peak The average hydrodynamic radius (R _H ) is 20 μm or less, preferably 15 μm or less, more preferably 10 μm or less, and the z-average fraction of its maximum peak is 0.20 or less, preferably 0.15 or less. More preferably, it is 0.10 or less, and when a plurality of polymer components are contained, at least one of them falls within the above range.

The evaluation method of the present invention measures the dynamic light scattering (DLS) of a product and a polymer solution for alignment film, and expresses the size of the dissolved unit in the solution of the alignment film polymer at a finite concentration. Since the pinhole defect at the time of printing of the alignment agent is evaluated by the radius (R _H ), firstly, a decrease in yield due to poor application of the alignment agent when applied on the substrate can be minimized. Secondly, it will be easier to evaluate and select polymers for alignment films that can improve pinhole defects due to the size distribution of the clusters formed by the polymer. It can be used very suitably for production.

[Dynamic light scattering measurement device]
Hereinafter, the present invention will be described in detail. A light scattering device manufactured by ALV Germany was used as a dynamic light scattering measuring device for measuring the diffusion coefficient, that is, the hydrodynamic radius (R _H ) from the fluctuation of the scattered light intensity of the polymer solution for the alignment film. The specifications of this apparatus are as follows: ALV / DLS / SLS-5022F (with Attenuator) as a goniometer, wavelength 632.8 nm, 22 mW He-Ne laser as a laser light source, and a dual avalanche photodiode (ALV-High) as a scattered light detector. QE APD × 2) + beam splitter, ALV-5000 / EPP + Fast mode measurement ALV-6010 / 160 as a correlator. The control / analysis program used was ALV-5000E / WIN (ver. 3). As the laser light source, an Ar laser (wavelength 488 nm), a solid-state semiconductor laser (YAG second harmonic, wavelength 532 nm), etc. are used, and for example, a photomultiplier tube (photomultiplier), a photodiode is used as the scattered light detector. Etc. can be used.

[Composition for liquid crystal aligning agent]
The liquid crystal aligning agent of the present invention is constituted by dissolving a polymer such as polyamic acid in a solvent. As the polymer component in the present invention, preferably, a polyamic acid having a repeating unit represented by the above formula (I-1), an imidized polymer having a repeating unit represented by the following formula (I-2), A block copolymer having an amic acid prepolymer having a repeating unit represented by the following formula (I-1) and an imide prepolymer having a repeating unit represented by the following formula (I-2); Can be mentioned.

In the formula, P ¹ is a tetravalent organic group, and Q ¹ is a divalent organic group.

In the formula, P ² is a tetravalent organic group, and Q ² is a divalent organic group.

  These may be used alone or in combination of two or more. When two or more types are used in combination, it is preferable to use a mixture of polyamic acid and imidized polymer. In the above formula (I-1), the polyamic acid is obtained by reacting a tetracarboxylic dianhydride and a diamine, and the imidized polymer is obtained by dehydrating and ring-closing the polyamic acid. In the imidized polymer, 100% of the repeating units may not be dehydrated and closed, and the ratio of repeating units having an imide ring in all repeating units (hereinafter also referred to as “imidation rate”) is less than 100%. It may be.

<Tetracarboxylic dianhydride>
Specific examples of tetracarboxylic dianhydrides used for the synthesis of polyamic acid include, for example, 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 Anhydride, 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, cis-3,7-dibutylcycloocta-1,5-diene-1,2 5,6-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-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-hexahydro-5,8- Methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -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] An alicyclic ring represented by octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), represented by the following formulas (I) and (II) Formula tetracarboxylic dianhydride;

(Wherein R ³ and R ⁶ represent a divalent organic group having an aromatic ring, R ⁴ and R ⁵ represent a hydrogen atom or an alkyl group, and a plurality of R ⁴ and R ⁵ are the same. But it may be different.)

An aliphatic tetracarboxylic dianhydride such as butanetetracarboxylic dianhydride;
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, 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 (anhydro trimellitate), propylene glycol-bis (anhydro trimellitate) 1,4-butanediol-bis (anhydrotrimellitate), 1,6-hexanediol-bis (anhydride) Trimetrate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate), the following formulas (1) to (4) An aromatic tetracarboxylic dianhydride such as an aromatic tetracarboxylic dianhydride having a steroid skeleton represented by each of the above can be given. These may be used alone or in combination of two or more.

  Of these, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4- Tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2 , 5,6-tetracarboxylic dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 1,3,3a, 4,5,9b- Hexahydro-5- (te Lahydro-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), above Of the compounds represented by formula (I), each of the following formulas (5) to (7) Of the compounds represented by formula (II), the compound represented by the following formula (8), butanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride and the like are good. It is preferable from the viewpoint that liquid crystal orientation and electrical characteristics can be expressed, and these are used alone or in combination of two or more.

<Diamine>
Examples of diamines used for the synthesis of polyamic acid include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl sulfide, 4 , 4′-diaminodiphenylsulfone, 2,2′-dimethyl-4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, 4,4 '-Diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3-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′-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, 9,9-bis (4-aminophenyl) -10- Hydroanthracene, 2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 4,4′-methylene-bis (2-c Roaniline), 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 (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino- Aromatic diamines such as 2-trifluoromethyl) phenoxy] -octafluorobiphenyl;

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 4,4'-methylenebis (cyclohexylamine);

1,2,3-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, -Diaminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6 -Two primary amino groups in the molecule, such as phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine, and nitrogen other than the primary amino group Examples thereof include diamines having atoms; diaminoorganosiloxanes represented by the following formula (III). These diamines can be used alone or in combination of two or more.

(Wherein R ⁷ represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ⁷ may be the same or different, p is an integer of 1 to 3, and q is 1 to 20) Is an integer.)

  Of these, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 2,2′-dimethyl-4,4′-diaminobiphenyl, 1,5-diaminonaphthalene, 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'-methyle Bis (cyclohexylamine), 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4 -Diaminopyrimidine, 3,6-diaminoacridine and the like are preferable.

When the liquid crystal aligning agent of the present invention has pretilt angle expression, Q ¹ in the above formula (I-1) and / or part or all of Q ^{2 in} the above formula (I-2) is represented by the following formula ( Q-1) and at least one of the groups represented by the following formula (Q-2) are preferable. That is, a diamine having a group represented by the following formula (Q-1) or the following formula (Q-2) (hereinafter also referred to as “specific diamine”) is preferably used. These may be used alone or in combination of two or more.

(In the formula, X is a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S— or an arylene group, and R ¹ has 10 carbon atoms. An alkyl group of -20, a monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms, or a monovalent organic group having a fluorine atom having 6 to 20 carbon atoms.)

(In the formula, X is a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S— or an arylene group, and R ² has 4 carbon atoms. It is a divalent organic group having an alicyclic skeleton of ˜40.)

In the above formula (Q-1), examples of the alkyl group having 10 to 20 carbon atoms represented by R ¹ include n-decyl group, n-dodecyl group, n-pentadecyl group, n-hexadecyl group, n- An octadecyl group, n-eicosyl group, etc. are mentioned. In addition, as the monovalent or divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms represented by R ¹ in the above formula (Q-1) and R ² in the above formula (Q-2), For example, a group having an alicyclic skeleton derived from a cycloalkane such as cyclobutane, cyclopentane, cyclohexane or cyclodecane; a group having a steroid skeleton such as cholesterol or cholestanol; a group having a bridged alicyclic skeleton such as norbornene or adamantane Etc. Among these, a group having a steroid skeleton is particularly preferable. The organic group having an alicyclic skeleton may be a group substituted with a halogen atom, preferably a fluorine atom, or a fluoroalkyl group, preferably a trifluoromethyl group.

Furthermore, examples of the monovalent organic group having a fluorine atom having 6 to 20 carbon atoms represented by R ¹ in the formula (Q-1) include an n-hexyl group, an n-octyl group, and an n-decyl group. Straight chain alkyl groups having 6 or more carbon atoms such as: alicyclic hydrocarbon groups having 6 or more carbon atoms such as cyclohexyl groups and cyclooctyl groups; aromatic hydrocarbon groups having 6 or more carbon atoms such as phenyl groups and biphenyl groups And a group in which some or all of the hydrogen atoms in an organic group such as the above are substituted with a fluoroalkyl group such as a fluorine atom or a trifluoromethyl group.

  X in the formula (Q-1) and the formula (Q-2) is a single bond, -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH-, -S. -Or an arylene group. Examples of the arylene group include a phenylene group, a tolylene group, a biphenylene group, and a naphthylene group. Of these, groups represented by —O—, —COO—, and —OCO— are particularly preferable. Specific examples of the diamine having the group represented by the formula (Q-1) include dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy- Preferable examples include 2,4-diaminobenzene and compounds represented by the following formulas (9) to (14).

  Specific examples of the diamine having a group represented by the above formula (Q-2) include diamines represented by the following formulas (15) to (17).

  Of these, particularly preferred are compounds represented by the above formulas (9), (10), (13), (14) and (15).

  The use ratio of the specific diamine with respect to the total amount of diamine varies depending on the size of the pretilt angle to be expressed. 5 to 100 mol% is preferable.

<Synthesis of polyamic acid>
The ratio of tetracarboxylic dianhydride and diamine used in the polyamic acid synthesis reaction is 0.2 to 2 equivalents of tetracarboxylic dianhydride acid anhydride group to 1 equivalent of amino group of diamine. The ratio is preferably, more preferably 0.3 to 1.2 equivalent. The polyamic acid synthesis reaction is preferably performed in an organic solvent under a temperature condition of −20 ° C. to 150 ° C., more preferably 0 to 100 ° C. Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized polyamic acid. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide And aprotic polar solvents such as γ-butyrolactone, tetramethylurea and hexamethylphosphortriamide; and phenolic solvents such as m-cresol, xylenol, phenol and halogenated phenol. The amount of organic solvent used (α) is such that the total amount (β) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight with respect to the total amount (α + β) of the reaction solution. It is preferable that

  Alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc., which are poor solvents for polyamic acid, may be used in combination with the organic solvent as long as the polyamic acid to be produced does not precipitate. it can. Specific examples of the poor solvent include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), ethylene glycol, propylene glycol, 1,4-butane. Diol, triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, Diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether Ethylene glycol-i-propyl ether, ethylene glycol-n-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 Examples include acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, and the like.

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

<Synthesis of imidized polymer>
The imidized polymer can be synthesized by dehydrating and ring-closing part or all of the polyamic acid. The imidation ratio is preferably 40 mol% or more, particularly preferably 70 mol% or more. By using a polymer having an imidization ratio of 40 mol% or more, a liquid crystal aligning agent capable of forming a liquid crystal alignment film having a short afterimage erasing time can be obtained.

  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 imidized polymer obtained may decrease.

  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 repeating units of 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. The amount of the dehydration ring-closing catalyst used is preferably 0.01 to 10 mol with respect to 1 mol of the dehydrating agent used. The imidation rate can be increased as the amount of the above dehydrating agent and dehydrating ring-closing agent increases. Examples of the organic solvent used in the dehydration ring closure reaction include the same organic solvents as exemplified for use in the synthesis of polyamic acid. And reaction temperature of dehydration ring closure reaction becomes like this. Preferably it is 0-180 degreeC, More preferably, it is 10-150 degreeC. Moreover, the obtained imidized polymer can be refine | purified by performing operation similar to the purification method of polyamic acid with respect to the reaction solution obtained in this way.

<End-modified polymer>
The polymer used in the present invention may be a terminal-modified type having a controlled molecular weight. By using this terminal-modified polymer, the coating characteristics of the liquid crystal aligning agent can be improved without impairing the effects of the present invention. Such a terminal-modified polymer can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when synthesizing a polyamic acid. Here, 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 and the like. Examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, and n-undecylamine. N-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, etc. Can do. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

<Shear viscosity of polymer>
The polymer obtained as described above preferably has a shear viscosity value in the range of 10 to 100 mPa · s, more preferably 20 to 20% when measured at a solid content concentration of 4% by weight. 60 mPa · s. When the shear viscosity is too low, the fluidity of the liquid crystal aligning agent is too high, so that it is difficult to hold the liquid on the substrate during application to the substrate. When the shear viscosity is too high, the cohesiveness of the liquid crystal aligning agent increases, and pinhole-like defects or the like are likely to occur during coating. The shear viscosity value in the present invention is the viscosity of Toki Sangyo Co., Ltd. for a solution in which N-methyl-2-pyrrolidone is used as a solvent and the polymer is dissolved so that the solid concentration is 4.0% by weight. Measured with a total of RE100RL.

<Block copolymer>
When the above-described block copolymer is used as the polymer component used in the present invention, an amic acid prepolymer having an amino group or an acid anhydride group at the terminal and an imide having an acid anhydride group or an amino group at the terminal A block copolymer can be obtained by respectively synthesizing a prepolymer and bonding the terminal amino group and acid anhydride group of each prepolymer. The method for synthesizing the amic acid prepolymer is the same as the method for synthesizing the polyamic acid described above, and the method for synthesizing the imide prepolymer is the same as the method for synthesizing the imidized polymer described above. The functional group at the end can be selected by adjusting the amounts of tetracarboxylic dianhydride and diamine during polyamic acid synthesis.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention is constituted by dissolving the polymer component in a solvent. An organic solvent is used as the solvent. The temperature for preparing the liquid crystal aligning agent of the present invention is preferably 0 ° C to 200 ° C, more preferably 20 ° C to 60 ° C.

  Examples of the organic solvent constituting the liquid crystal aligning agent of the present invention include the same solvents exemplified as those used for the polyamic acid synthesis reaction, and those that can be used in combination during the polyamic acid synthesis reaction. The poor solvent exemplified as can also be appropriately selected and used in combination. It is preferable to use at least one organic solvent selected from γ-butyrolactone and / or N-methyl-2-pyrrolidone and a poor solvent butyl cellosolve, and it is particularly preferable to use a mixture of both. When an imidized polymer and / or a block copolymer is used as the polymer component, the total content of γ-butyrolactone and / or N-methyl-2-pyrrolidone and butyl cellosolve is 80% by weight based on the whole solvent. It is preferable that the amount be 85% by weight or more. When both are used in mixture, the mixing ratio thereof is preferably 50 to γ-butyrolactone and / or N-methylpyrrolidone with respect to the total amount of γ-butyrolactone and / or N-methylpyrrolidone and butyl cellosolve. 100% by weight, particularly preferably 80 to 100% by weight. Further, when γ-butyrolactone and N-methylpyrrolidone are mixed and used, the mixing ratio is such that N-methyl-2-pyrrolidone is based on the total amount of the mixed solvent of γ-butyrolactone and N-methylpyrrolidone. Preferably it is 0.1 to 50 weight%, More preferably, it is 0.1 to 30 weight%. Even when a polyamic acid is used as the polymer component, the total content of γ-butyrolactone and / or N-methyl-2-pyrrolidone and butyl cellosolve is preferably 80% by weight or more based on the entire solvent, and 85% by weight. % Or more is particularly preferable. Moreover, when both are used in mixture, the mixing ratio is preferably 30 to γ-butyrolactone and / or N-methylpyrrolidone relative to the total amount of γ-butyrolactone and / or N-methylpyrrolidone and butyl cellosolve. 80% by weight, particularly preferably 30 to 50% by weight. Further, when γ-butyrolactone and N-methylpyrrolidone are mixed and used, the mixing ratio is such that N-methyl-2-pyrrolidone is based on the total amount of the mixed solvent of γ-butyrolactone and N-methylpyrrolidone. Preferably it is 30-100 weight%, More preferably, it is 50-100 weight%. The solid content concentration in the liquid crystal aligning agent of the present invention is selected in consideration of viscosity, volatility, etc., but is in the range of 1 to 7% by weight, preferably 2 to 7% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface to form a coating film that becomes a liquid crystal alignment film. When the solid content concentration is less than 1% by weight, the coating film thickness is When the solid content concentration exceeds 7% by weight, the film thickness of the coating film becomes excessive and a good liquid crystal alignment film cannot be obtained. In addition, the viscosity of the liquid crystal aligning agent is increased, resulting in poor coating properties, and the cohesiveness of the liquid crystal aligning agent is increased, so that pinhole defects are easily generated.

<Adhesion aid>
The liquid crystal aligning agent of the present invention may contain a functional silane-containing compound or an epoxy group-containing compound from the viewpoint of improving the adhesion to the substrate surface. Examples of such functional silane-containing compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl). -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-amino Propyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl- , 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 (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, etc. can be mentioned. Examples of the epoxy group-containing 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, 1, 6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentylglycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ′, N ′,-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N ′,-tetraglycidyl-4, Preferred examples include 4′-diaminodiphenylmethane. The blending ratio of these functional silane-containing compounds and epoxy group-containing compounds is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the polymer.

<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) A liquid crystal aligning agent is applied to one surface of a substrate provided with a patterned transparent conductive film by a flexographic printing method, and then the coated surface is formed by heating the coated surface. 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, or polycarbonate can be used. As the transparent conductive film provided on one surface of the substrate, for example, 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, for example, 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 can also The heating temperature after application of the liquid crystal aligning agent is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The liquid crystal aligning agent of the present invention containing a polyamic acid forms a coating film that becomes an alignment film by removing the organic solvent after coating. It can also be a membrane. The film thickness of the formed coating film is preferably 0.001-1 μm, more preferably 0.005-0.5 μm.

(2) A rubbing process is performed in which the formed coating film surface is rubbed in a certain direction with a roll wound with a cloth made of a fiber such as nylon, rayon, or 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, by partially irradiating the liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention with ultraviolet rays as disclosed in, for example, JP-A-6-222366 and JP-A-6-281937. A resist film is partially formed on the surface of the liquid crystal alignment film that has been subjected to a treatment for changing the pretilt angle or a rubbing treatment as disclosed in JP-A-5-107544, which is different from the previous rubbing treatment. The visibility characteristics of the liquid crystal display element can be improved by removing the resist film after performing the rubbing treatment in the direction and changing the liquid crystal alignment ability of the liquid crystal alignment film.

(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. A polarizing plate is disposed on the outer surface of the liquid crystal cell, that is, the other surface of each substrate constituting the liquid crystal cell, and the polarization direction thereof coincides with or is orthogonal to the rubbing direction of the liquid crystal alignment film formed on one surface of the substrate. A liquid crystal display element is obtained by pasting together. 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 a nematic liquid crystal and a 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, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, and bicyclooctane. Type liquid crystal, cubane type liquid crystal and the like can be used. Further, for these liquid crystals, for example, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, cholesteryl carbonate, and chiral agents such as those sold under the trade names “C-15” and “CB-15” (manufactured by Merck). Etc. can also be used. Furthermore, a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate can also be used. In addition, as a polarizing plate bonded to the outer surface of the liquid crystal cell, for example, a polarizing plate in which a polarizing film called an H film that absorbs iodine while sandwiching and stretching polyvinyl alcohol is sandwiched between cellulose acetate protective films or H A polarizing plate made of the film 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. Each measurement and evaluation in Examples and Comparative Examples was performed by the following methods.

[Hydrodynamic radius of aggregate (R _H )]
For the polymers obtained in Synthesis Examples 1 and 2 and Comparative Synthesis Example 1 below, a solution having a specified concentration of 7.3% by weight was prepared, and then sufficiently stirred with a rotor to obtain a uniform solution. The mixing ratio of the solvent used at this time was γ-butyrolactone / N-methyl-2-pyrrolidone = 81.3 / 11.4 (% by weight). This resin solution was filtered through a filter (for polar solvent) having a pore diameter of 0.45 μm, and poured into a quartz glass cell having a diameter of 20 mm that had been washed with a methanol reflux washer for 2 hours or more. Since the solution viscosity depends on the temperature, dynamic light scattering measurement was performed with precise control at 23.00 ± 0.02 ° C. By CONTIN analysis, the diffusion coefficient, ie the z-average distribution of the hydrodynamic radius (R _H ) was obtained. The peak top value of the maximum peak was determined from the obtained distribution map.

[Printability test of liquid crystal alignment agent]
A 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 dried on a hot plate at 80 ° C. for 1 minute. Thereafter, the film was dried on a hot plate at 180 ° C. for 20 minutes to form a film having an average film thickness of 600 Å. The substrate was observed with a microscope with a magnification of 20 times for the presence of printing unevenness and pinhole-like defects, and the printability was judged accordingly.

[Orientation of liquid crystal display elements]
The presence or absence of a bright spot when the voltage was turned on / off (applied / released) to the liquid crystal display element was observed with a polarizing microscope, and the case where there was no bright spot was determined as “good”.

Synthesis example 1
219.69 g (0.98 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 106.52 g (0.985 mol) of p-phenylenediamine as a diamine compound, 9.81 g (0.015 mol) of the diamine represented by 9) was dissolved in 4500 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 280 g of polyamic acid having a shear viscosity of 13 mPa · s at a solid content concentration of 4% by weight. 30 g of the resulting polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, 23.4 g of pyridine and 18.1 g of acetic anhydride were added, and dehydration was carried out at 110 ° C. for 4 hours, followed by precipitation, washing, The pressure was reduced to obtain 17.8 g of a polyimide having a shear viscosity of 23 mPa · s at a solid content concentration of 4% by weight (hereinafter referred to as “polyimide (A-1)”).

Synthesis example 2
2,3,5-tricarboxycyclopentylacetic acid dianhydride 221.93 g (0.99 mol) as tetracarboxylic dianhydride, p-phenylenediamine 106.52 g (0.985 mol) as the diamine compound, 9.81 g (0.015 mol) of the diamine represented by 9) was dissolved in 4500 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 290 g of polyamic acid having a shear viscosity of 34 mPa · s at a solid content concentration of 4% by weight. 30 g of the resulting polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, 23.4 g of pyridine and 18.1 g of acetic anhydride were added, and dehydration was carried out at 110 ° C. for 4 hours, followed by precipitation, washing, The pressure was reduced to obtain 18.3 g of polyimide having a shear viscosity of 56 mPa · s at a solid content concentration of 4% by weight (hereinafter referred to as “polyimide (A-2)”).

Comparative Synthesis Example 1
224.17 g (1.00 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 106.52 g (0.985 mol) of p-phenylenediamine as a diamine compound, 9.81 g (0.015 mol) of the diamine represented by 9) was dissolved in 4500 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 260 g of polyamic acid having a shear viscosity of 52 mPa · s at a solid content concentration of 4% by weight. 30 g of the resulting polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, 23.4 g of pyridine and 18.1 g of acetic anhydride were added, and dehydration was carried out at 110 ° C. for 4 hours, followed by precipitation, washing, The pressure was reduced to obtain 19.0 g of polyimide having a shear viscosity of 74 mPa · s at a solid content concentration of 4% by weight (hereinafter referred to as “polyimide (A-3)”).

[Example]
For the imidized polymers obtained in Synthesis Examples 1 and 2 and Comparative Synthesis Example 1, the z-average distribution of the hydrodynamic radius (R _H ) was measured. The obtained results are shown in FIGS. In the figure, the peak of the distribution with the smallest hydrodynamic radius is derived from a single molecule, and a larger distribution is considered to be derived from an aggregate. The peak top value of the maximum peak is shown in Table 1.

  Using the imidized polymers obtained in Synthesis Examples 1 and 2 and Comparative Synthesis Example 1 in the weight ratio shown in Table 2 below, γ-butyrolactone / N-methylpyrrolidone / butyl cellosolve = 77/13/10 (% by weight) mixed A solution having a solid content concentration (TSC) of 8% by weight, 5% by weight, 4% by weight, 3% by weight and 1% by weight was prepared by dissolving in a solvent. Each of these solutions was filtered using a filter having a pore diameter of 1 μm to prepare the liquid crystal aligning agent of the present invention. A printability test was performed on each of the obtained liquid crystal aligning agents. The results are also shown in Table 2. Using a rubbing machine having a roll in which a rayon cloth is wound around a pair of coating film formation substrates obtained in a printability test, the rotational speed of the roll is 400 rpm, the moving speed of the stage is 3 cm / second, and the indentation length is 0 The rubbing process was performed at 4 mm. The substrate is immersed in ultrapure water for 1 minute, and then dried on a hot plate at 100 ° C. for 5 minutes, and aluminum oxide spheres having a diameter of 5.5 μm are placed on the outer edges of the obtained pair of liquid crystal sandwich substrates. After the epoxy resin adhesive was applied, the pair of liquid crystal sandwich substrates were superposed and pressure-bonded so that the liquid crystal alignment film faces each other, and the adhesive was cured. Next, after filling a nematic liquid crystal (MLC-6221 manufactured by Merck & Co., Inc.) between a pair of substrates from the liquid crystal injection port, the liquid crystal injection port is sealed with an acrylic photo-curing adhesive, and the both sides on the outside of the substrate are sealed. A polarizing plate was laminated to prepare a liquid crystal display element. The orientation of the obtained liquid crystal display element was confirmed. The results are also shown in Table 2.

Using the evaluation method of the present invention, the z-average distribution of the hydrodynamic radius (R _H ) of the aggregate in the alignment layer polymer solution was measured by this evaluation method. Printing can be performed by using an aligning agent having a small peak top hydrodynamic radius (R _H ) of the aggregate maximum peak or an average hydrodynamic radius (R _H ) of the maximum peak and a small z-average fraction of the maximum peak. Therefore, the yield during production of the liquid crystal panel is good, and the quality of the alignment film is uniform, so that the display quality of the liquid crystal panel can be improved. The liquid crystal display element having the liquid crystal alignment film of the present invention can be suitably used for TN type, STN type, and VA type liquid crystal display elements, and by selecting a liquid crystal to be used, an SH (Super Homeotropic) type, IPS It can also be suitably used for (In-Plane Switching) type, ferroelectric and antiferroelectric liquid crystal display elements. Furthermore, the liquid crystal display element having the liquid crystal alignment film of the present invention can be effectively used in various devices, for example, a desk calculator, wristwatch, table clock, mobile phone, coefficient display board, word processor, personal computer, liquid crystal television, liquid crystal data projector. It is used for display devices.

It is a dynamic light scattering measurement result of polymer A-1. It is a dynamic light scattering measurement result of polymer A-2. It is a dynamic light scattering measurement result of polymer A-3.

Claims (6)

The dynamic light scattering of the organic polymer solution is measured, and the maximum size of the aggregate derived from the organic polymer component or the position of the peak top is determined from the measured dynamic light scattering. An evaluation method of an organic polymer solution, characterized by evaluating printability when a molecular polymer solution is used as a liquid crystal aligning agent. The peak-top hydrodynamic radius (R _H ) of the maximum peak of the aggregate derived from the organic polymer component, or the hydrodynamic radius of the maximum peak (measured in dynamic light scattering measurement of the organic polymer solution) R _H ) has an average value of 20 μm or less, provided that when a plurality of organic high molecular weight polymers are contained, at least one of them satisfies the above relationship, and the solid content concentration is 2 A liquid crystal aligning agent comprising an organic polymer solution in a range of ˜7 wt% The peak-top hydrodynamic radius (R _H ) of the maximum peak of the aggregate derived from the organic polymer component, or the hydrodynamic radius of the maximum peak (measured in dynamic light scattering measurement of the organic polymer solution) R _H ) has an average value of 20 μm or less and a maximum peak z-average fraction of 0.20 or less, provided that it contains at least one of the organic polymer polymers in a plurality of components. Satisfying the above relationship, a liquid crystal aligning agent comprising an organic polymer solution. The organic polymer is a polymer having at least one selected from a repeating unit represented by the following formula (I-1) and a repeating unit represented by the following formula (I-2), and further containing a solvent The liquid crystal aligning agent according to claim 2 or 3.

(In the formula, P ¹ is a tetravalent organic group, and Q ¹ is a divalent organic group.)

(In the formula, P ² is a tetravalent organic group, and Q ² is a divalent organic group.) The liquid crystal aligning agent according to any one of claims 2 to 4, wherein 70% by weight or more of the organic polymer has a shear viscosity of 20 to 60 mPa · s at a solid content concentration of 4% by weight. The organic high molecular polymer contains an imidized polymer having a total of 90 mol% or more of repeating units derived from 2,3,5-tricarboxycyclopentylacetic acid dianhydride and p-phenylenediamine. The liquid crystal aligning agent in any one of 2-5.

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