JP6384663B2 - Polymer, liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Description

  The present invention relates to a polymer useful for preparing a liquid crystal alignment film, a liquid crystal alignment agent containing the polymer, a liquid crystal alignment film using the liquid crystal alignment agent, and a liquid crystal display device including the liquid crystal alignment film. Is.

  In a liquid crystal display element used for a liquid crystal display or the like, a liquid crystal alignment film plays a role of aligning liquid crystals in a certain direction. As a liquid crystal alignment film, a polyimide-based film formed by applying a polyamic acid (also called a polyamic acid), which is a polyimide precursor, or a liquid crystal aligning agent mainly composed of a soluble polyimide solution to a substrate and baking it. Are mainly used.

  However, in a liquid crystal display element having this type of liquid crystal alignment film, a DC voltage remains even after the voltage application is released due to long-term continuous driving or the like (residual voltage; RDC), and the liquid crystal alignment is affected by this residual voltage. There is a problem that an afterimage (burn-in) occurs on the display screen. For this reason, various proposals have been made for the purpose of suppressing the burn-in due to the residual voltage, that is, shortening the erasure time of the afterimage generated after the voltage application is canceled.

  For example, it is proposed that a tertiary amine having a predetermined structure is mixed to form a liquid crystal aligning agent (see, for example, Patent Document 1). In addition, a liquid crystal aligning agent containing a diamine compound having a ring structure containing a nitrogen atom and containing a soluble imidized polymer having an intrinsic viscosity adjusted to a predetermined range has been proposed (for example, see Patent Document 2). In addition, a liquid crystal aligning agent including a compound containing one carboxylic acid group in the molecule and a compound containing one tertiary amine group in the molecule has been proposed (for example, see Patent Document 3).

  Moreover, the diamine compound which has a nitrogen-containing aromatic ring in a side chain is proposed (for example, refer patent document 4). In addition, a predetermined diamine compound having one primary amino group and a nitrogen-containing aromatic heterocyclic ring in the molecule has been proposed (see, for example, Patent Document 5). Moreover, the diamine compound which has a predetermined | prescribed secondary amine structure is proposed (for example, refer patent document 6).

JP 09-316200 A JP-A-10-104633 Japanese Patent Laid-Open No. 08-76128 International Publication No. 2009/093704 Pamphlet International Publication No. 2008/013285 Pamphlet International Publication No. 2004/021076 Pamphlet

  However, in recent years, liquid crystal display elements have been improved in performance, increased in area, and reduced in power consumption of display devices. In addition, liquid crystal display elements have been used in various environments, and liquid crystal alignment films have been demanded. The characteristics that can be achieved have also become severe. As the use of liquid crystal display elements such as large-screen LCD TVs, high-definition mobile applications (display parts of digital cameras and mobile phones), and in-vehicle applications (car navigation systems and meter panels) exposed to high temperatures, Before the problem of image sticking due to the residual voltage, the problem that it is difficult to ensure good liquid crystal alignment and the problem that the voltage holding characteristic is deteriorated in a high temperature environment become prominent.

  If good liquid crystal alignment cannot be ensured, light leakage and alignment failure are likely to occur, and if the voltage holding characteristics are reduced, power consumption is increased and display characteristics are reduced. For this reason, although there is a strong demand for providing a technology capable of ensuring good liquid crystal alignment properties, excellent voltage holding characteristics, and further capable of suppressing image sticking, the conventionally proposed technology requires this. The request cannot be met.

  The present invention has been made in view of the above circumstances, and is useful for producing a liquid crystal alignment film that can ensure good liquid crystal alignment, has excellent voltage holding characteristics, and can suppress image sticking. It is an object of the present invention to provide a polymer, a liquid crystal aligning agent containing the polymer, a liquid crystal aligning film obtained from the liquid crystal aligning agent, and a liquid crystal display device having the liquid crystal aligning film.

  As a result of intensive studies, the present invention has revealed that a polymer, a liquid crystal aligning agent, a liquid crystal aligning film, and a polymer obtained using a diamine having both an amide bond (—NHCO—) and a carboxyl group (—COOH) in the side chain The present inventors have found that a liquid crystal display element is effective for achieving the above object, and have completed the present invention. The present invention has the following gist.

  1. A polyamic acid obtained by reacting a diamine component containing a diamine represented by the following formula [1] with a tetracarboxylic acid derivative, a polyamic acid ester, or the polyamic acid and / or polyamic acid ester is dehydrated and closed (imide) A polymer comprising a polyimide obtained by

（式中、Ｒ_１は、エーテル結合、チオエーテル結合、アミド結合、又は炭素数１〜１０で形成されるアルキレン基、アルケニル基、アルキニル基、脂環式炭化水素及び芳香族炭化水素からなる群より選ばれる結合基である。Ｒ_１に炭素原子が含まれる場合、該炭素原子に結合する水素原子は、ハロゲン含有アルキル基、ハロゲン原子、水酸基、及びカルボキシル基からなる群より選ばれる少なくとも１種で置換されていてもよい。）

(In the formula, R ₁ is an ether bond, a thioether bond, an amide bond, or an alkylene group, alkenyl group, alkynyl group, alicyclic hydrocarbon and aromatic hydrocarbon formed of 1 to 10 carbon atoms. When R ₁ contains a carbon atom, the hydrogen atom bonded to the carbon atom is at least one selected from the group consisting of a halogen-containing alkyl group, a halogen atom, a hydroxyl group, and a carboxyl group. May be substituted.)

2. In the formula [1], R ₁ is an alkylene group having 1 to 3 carbon atoms, and the hydrogen atom bonded to the carbon atom contained in R ₁ may be substituted with a carboxyl group. The above 1. The polymer described in 1.

  3. The diamine represented by the formula [1] is at least one diamine selected from the group represented by the following formulas [DA1] to [DA3]. ~ 2. The polymer described in 1.

  4). The diamine component contains 5 mol% or more of the diamine represented by the formula [1]. ~ 3. The polymer as described in any one of these.

  5. Above 1. ~ 4. A liquid crystal aligning agent comprising the polymer according to any one of the above.

  6). 5. above. A liquid crystal aligning film comprising the liquid crystal aligning agent described in 1.

  7). Above 6. A liquid crystal display element comprising the liquid crystal alignment film described in 1.

  According to the present invention, it is possible to provide a polymer, a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element that can ensure good liquid crystal alignment properties, have excellent voltage holding characteristics, and can suppress image sticking. .

（式中、Ｒ_１は、エーテル結合、チオエーテル結合、アミド結合、又は炭素数１〜１０で形成されるアルキレン基、アルケニル基、アルキニル基、脂環式炭化水素及び芳香族炭化水素からなる群より選ばれる結合基である。Ｒ_１に炭素原子が含まれる場合、該炭素原子に結合する水素原子は、ハロゲン原子、ハロゲン含有アルキル基、水酸基、及びカルボキシル基からなる群より選ばれる少なくとも１種で置換されていてもよい。） Hereinafter, an embodiment of the present invention will be described in detail.
The polymer according to this embodiment is useful for producing a liquid crystal alignment film, and is a polyamic obtained by reacting a diamine component containing a diamine represented by the following formula [1] with a tetracarboxylic acid derivative. It consists of a polyimide obtained by dehydrating and ring-closing (imidizing) an acid, a polyamic acid ester, or the polyamic acid and / or polyamic acid ester.

(In the formula, R ₁ is an ether bond, a thioether bond, an amide bond, or an alkylene group, alkenyl group, alkynyl group, alicyclic hydrocarbon and aromatic hydrocarbon formed of 1 to 10 carbon atoms. When R ₁ contains a carbon atom, the hydrogen atom bonded to the carbon atom is at least one selected from the group consisting of a halogen atom, a halogen-containing alkyl group, a hydroxyl group, and a carboxyl group. May be substituted.)

<Diamine component>
The diamine component used in the present embodiment includes a diamine represented by the above formula [1]. According to such a diamine, since it has both an amide bond (—NHCO—) and a carboxyl group (—COOH) in the side chain, the amide bond—amide bond, amide bond—carboxyl group, carboxyl group—carboxyl group Interaction occurs, and proton transfer is likely to occur. Such an electrochemically active state not only lowers the residual voltage, but also contributes to the improvement of voltage holding characteristics because it has a function of trapping impurity components in the liquid crystal. Further, due to the interaction between the structures, the molecular alignment controllability is improved, and good liquid crystal alignment can be ensured. Therefore, by reacting the diamine component containing the diamine represented by the above formula [1], good liquid crystal orientation can be ensured, excellent in voltage holding characteristics, and further, image sticking can be suppressed. A polymer useful for producing a film, a liquid crystal aligning agent containing the polymer, a liquid crystal aligning film using the liquid crystal aligning agent, and a liquid crystal display device comprising the liquid crystal aligning film can be obtained.

Of the R ₁ , examples of the alkylene group formed of 1 to 10 carbon atoms include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, and an octylene group. These may be linear or branched.

Moreover, examples of the alkenyl group having 1 to 10 carbon atoms in R ₁ include a methenyl group, a vinyl group, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, and an octenyl group. . These may be linear or branched.

Moreover, examples of the alkynyl group formed of 1 to 10 carbon atoms in R ₁ include methynyl group, ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group, heptynyl group, octynyl group, and the like. . These may be linear or branched.

Further, among the above R ₁ , examples of the alicyclic hydrocarbon formed of 1 to 10 carbon atoms include monocyclic or polycyclic hydrocarbons (alkyl groups and alkenyl groups), such as a cyclopropyl group. , Cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, bicyclooctyl group, norbornyl group, cyclopropenyl group, cyclopentenyl group, cyclohexenyl group and the like.

Further, among the above R ₁ , examples of the aromatic hydrocarbon formed of 1 to 10 carbon atoms include monocyclic or polycyclic aryl groups. In the case of a polycyclic aryl group, in addition to complete unsaturation, Also includes partially saturated groups. Examples thereof include a phenyl group, a naphthyl group, an azulenyl group, an indenyl group, an indanyl group, and a tetralinyl group.

When R ₁ contains a carbon atom and there is a hydrogen atom bonded to the carbon atom, the hydrogen atom is at least one selected from the group consisting of a halogen atom, a halogen-containing alkyl group, a hydroxyl group, and a carboxyl group. May be substituted. Examples of the halogen atom mentioned here include chlorine, bromine, iodine and the like. Moreover, as a halogen-containing alkyl group, the alkyl group containing said halogen atom is mentioned, For example, the C1-C5 alkyl group containing said halogen atom is mentioned.

From the above, in this embodiment, as the diamine represented by the above formula [1], for example, at least one selected from the group represented by the following formulas [DA1] to [DA3] can be used. Of course, two or more of these diamines may be used in combination. Table 1, correspondence between these diamines and the R ₁ is shown.

Among them, the diamine represented by the formula [1] is preferably an alkylene group in which R ₁ is formed of 1 to 3 carbon atoms, and a hydrogen atom bonded to a carbon atom contained in R ₁ is , Which may be substituted with a carboxyl group. More preferred is a diamine represented by the above formulas [DA1] to [DA3]. According to these, good liquid crystal alignment can be ensured by the interaction between partial structures such as amide bond-amide bond, amide bond-carboxyl group, carboxyl group-carboxyl group, excellent voltage holding characteristics, and image sticking. It becomes easy to suppress. Of course, two or more diamines represented by the above formulas [DA1] to [DA3] may be used in combination.

  In the above formula [1], the position of each amino group bonded to the benzene ring is not limited, but from the viewpoint of the difficulty of synthesis and the availability of reagents, the position of the amide bond bonded to the benzene ring is used as a reference. The position is preferred. These amino groups may be protected with an organic group (for example, a tertiary butoxycarbonyl group) that can be removed by heat. The hydrogen atom bonded to the benzene ring may be substituted with an organic group (for example, a halogen atom, an alkyl group formed of 1 to 5 carbon atoms, etc.), but is preferably unsubstituted.

  The diamine represented by the above formula [1] is contained in an amount of 5 to 100 mol%, preferably 20 to 100 mol%, based on the total amount of the diamine component, and becomes the diamine component used in this embodiment. When the blending ratio of the diamine represented by the formula [1] is less than the above range, an effect due to the interaction between partial structures such as amide bond-amide bond, amide bond-carboxyl group, and carboxyl group-carboxyl group is obtained. It becomes difficult to be.

  The diamine represented by the above formula [1] is not limited to the above example. That is, as long as it is a diamine having both an amide bond and a carboxyl group in the side chain, and exhibits a desired function by the interaction between the partial structures as described above, such a diamine is also represented by the above formula. It can be used as a diamine represented by [1].

  In addition to the diamine represented by the above formula [1], the diamine component can ensure good liquid crystal alignment, has excellent voltage holding characteristics, and does not change the gist of the present invention that suppresses burn-in. As long as there is no excessive adverse effect on the production of the liquid crystal alignment film from the viewpoint of solubility and reactivity of the polymer, other diamines (diamines other than the diamine represented by the above formula [1]) are used alone or in combination. Two or more types can be included. Examples of other diamines include aromatic diamines, alicyclic diamines, and aliphatic diamines.

  Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4′-diaminodicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexylamine, isophorone diamine, and the like. Is mentioned.

  As aromatic diamines, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1,4-diamino-2 -Methoxybenzene, 2,5-diamino-p-xylene, 1,3-diamino-4-chlorobenzene, 3,5-diaminobenzoic acid, 1,4-diamino-2,5-dichlorobenzene, 4,4'- Diaminobenzanilide-, 4,4′-diamino-1,2-diphenylethane, 1,2-bis (4-aminophenoxy) ethane, 4,4′-diamino-2,2′-dimethylbibenzyl, 4, 4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diamino-3,3 -Dimethyldiphenylmethane, 2,2'-diaminostilbene, 4,4'-diaminostilbene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'- Diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 4,4′-diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4 -Bis (4-aminophenoxy) benzene, 3,5-bis (4-aminophenoxy) benzoic acid, 4,4'-bis (4-aminophenoxy) bibenzyl, 2,2-bis [(4-aminophenoxy) Methyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexaph Lopropane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 1, 1-bis (4-aminophenyl) cyclohexane, α, α′-bis (4-aminophenyl) -1,4-diisopropylbenzene, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis ( 3-aminophenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4′-diaminodiphenylamine, 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1,5- Diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrene, 1,6-diaminopyrene, , 8-diaminopyrene, 2,7-diaminofluorene, 1,3-bis (4-aminophenyl) tetramethyldisiloxane, benzidine, 2,2'-dimethylbenzidine, 1,2-bis (4-aminophenyl) Ethane, 1,3-bis (4-aminophenyl) propane, 1,4-bis (4-aminophenyl) butane, 1,5-bis (4-aminophenyl) pentane, 1,6-bis (4-amino) Phenyl) hexane, 1,7-bis (4-aminophenyl) heptane, 1,8-bis (4-aminophenyl) octane, 1,9-bis (4-aminophenyl) nonane, 1,10-bis (4 -Aminophenyl) decane, 1,3-bis (4-aminophenoxy) propane, 1,4-bis (4-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) ) Pentane, 1,6-bis (4-aminophenoxy) hexane, 1,7-bis (4-aminophenoxy) heptane, 1,8-bis (4-aminophenoxy) octane, 1,9-bis (4- Aminophenoxy) nonane, 1,10-bis (4-aminophenoxy) decane, di (4-aminophenyl) propane-1,3-dioate, di (4-aminophenyl) butane-1,4-dioate, di ( 4-aminophenyl) pentane-1,5-dioate, di (4-aminophenyl) hexane-1,6-dioate, di (4-aminophenyl) heptane-1,7-dioate, di (4-aminophenyl) Octane-1,8-dioate, di (4-aminophenyl) nonane-1,9-dioate, di (4-aminophenyl) decane-1,10-dioate 1,3-bis [4- (4-aminophenoxy) phenoxy] propane, 1,4-bis [4- (4-aminophenoxy) phenoxy] butane, 1,5-bis [4- (4-aminophenoxy) Phenoxy] pentane, 1,6-bis [4- (4-aminophenoxy) phenoxy] hexane, 1,7-bis [4- (4-aminophenoxy) phenoxy] heptane, 1,8-bis [4- (4 -Aminophenoxy) phenoxy] octane, 1,9-bis [4- (4-aminophenoxy) phenoxy] nonane, 1,10-bis [4- (4-aminophenoxy) phenoxy] decane and the like.

  Aromatic-aliphatic diamines include 3-aminobenzylamine, 4-aminobenzylamine, 3-amino-N-methylbenzylamine, 4-amino-N-methylbenzylamine, 3-aminophenethylamine, 4-aminophenethylamine 3-amino-N-methylphenethylamine, 4-amino-N-methylphenethylamine, 3- (3-aminopropyl) aniline, 4- (3-aminopropyl) aniline, 3- (3-methylaminopropyl) aniline, 4- (3-methylaminopropyl) aniline, 3- (4-aminobutyl) aniline, 4- (4-aminobutyl) aniline, 3- (4-methylaminobutyl) aniline, 4- (4-methylaminobutyl) ) Aniline, 3- (5-aminopentyl) aniline, 4- (5-aminopentyl) ani , 3- (5-methylaminopentyl) aniline, 4- (5-methylaminopentyl) aniline, 2- (6-aminonaphthyl) methylamine, 3- (6-aminonaphthyl) methylamine, 2- (6 -Aminonaphthyl) ethylamine, 3- (6-aminonaphthyl) ethylamine and the like.

  Heterocyclic diamines include 2,6-diaminopyridine, 2,4-diaminopyridine, 2,4-diamino-1,3,5-triazine, 2,7-diaminodibenzofuran, 3,6-diaminocarbazole, Examples include 2,4-diamino-6-isopropyl-1,3,5-triazine, 2,5-bis (4-aminophenyl) -1,3,4-oxadiazole.

  Examples of aliphatic diamines include 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, , 8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,3-diamino-2,2-dimethylpropane, 1,6-diamino-2,5-dimethylhexane, 1,7-diamino -2,5-dimethylheptane, 1,7-diamino-4,4-dimethylheptane, 1,7-diamino-3-methylheptane, 1,9-diamino-5-methylheptane, 1,12-diaminododecane, Examples include 1,18-diaminooctadecane and 1,2-bis (3-aminopropoxy) ethane.

  The diamine represented by the above formula [1] described above is a side chain corresponding to both the amide bond (—NHCO—) and the carboxyl group (—COOH), for example, as shown in the Examples section described later. Can be obtained by a method of synthesizing a dinitro compound having a nitro group and converting the nitro group to an amino group by reduction. Other diamines can also be synthesized by a conventional method.

<Tetracarboxylic acid derivative>
The tetracarboxylic acid derivative used in the present embodiment is not particularly limited, and any of those having an alicyclic structure, those having an aliphatic structure, and those having an aromatic structure can be used.

Examples of the tetracarboxylic dianhydride having an alicyclic structure or an aliphatic structure include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutane. Tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetra Carboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic Acid dianhydride, 3,4-dicarboxy-1-cyclohexyl succinic dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, 1, , 3,4-Butanetetracarboxylic dianhydride, bicyclo [3.3.0] octane-2,4,6,8-tetracarboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetra Carboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride , Tricyclo [4.2.1.0 ^2,5 ] nonane-3,4,7,8-tetracarboxylic acid-3,4: 7,8-dianhydride, hexacyclo [6.6.0.1 ^{2 , 7} . 0 ^3,6 . 1 ^9,14 . 0 ^10,13] hexadecane -4,5,11,12- tetracarboxylic acid-4,5: 11,12-dianhydride, 4- (2,5-di-oxo-tetrahydrofuran-3-yl) -1,2 3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride and the like.

  Examples of tetracarboxylic dianhydrides having aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3. , 3′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,3 , 3 ′, 4-benzophenonetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,2,5, Examples include 6-naphthalenetetracarboxylic dianhydride and 2,3,6,7-naphthalenetetracarboxylic dianhydride. It is preferable to use a tetracarboxylic dianhydride having an aromatic aromatic structure because the liquid crystal orientation is further improved and the accumulated charge of the liquid crystal cell is easily reduced.

  Moreover, in order to obtain the polyamic acid ester contained in the liquid crystal aligning agent of this embodiment, the tetracarboxylic-acid dialkyl ester made to react with a diamine component and the polyamide contained in the liquid crystal aligning agent of this embodiment react with a diamine component. The dicarboxylic acid to be produced is not particularly limited. The tetracarboxylic acid derivatives described above can be used alone or in combination of two or more.

  The tetracarboxylic acid derivative used in the present embodiment is not limited to these examples. If it is within the scope of the present invention that can react with the diamine represented by the above formula [1] to suitably obtain a predetermined polymer, other tetracarboxylic acid derivatives (tetracarboxylic acid derivatives other than those exemplified above) ) May also be available. Other tetracarboxylic acid derivatives can be used alone or in combination of two or more.

<Polymer obtained by reacting diamine component and tetracarboxylic acid derivative>
A polyimide precursor (polyamic acid) can be obtained by a reaction between a diamine component containing the diamine represented by the formula [1] and a tetracarboxylic acid derivative, and the carboxyl group of the polyamic acid is esterified. A polyamic acid ester can be obtained by converting to. Furthermore, a polyimide can be obtained by ring-closing (imidizing) a polyamic acid and this polyamic acid ester. Any of these polyamic acid, polyamic acid ester, and polyimide is useful as a polymer for obtaining a liquid crystal aligning agent. In addition, the dehydration ring closure rate (imidation rate) at the time of obtaining a polyimide does not necessarily need to be 100%, It can adjust arbitrarily according to a use and the objective in the range of 0% to 100%.

  In obtaining a polymer (polyamic acid, polyamic acid ester and polyimide) from the diamine component containing the diamine represented by the above formula [1] and the tetracarboxylic acid derivative, the diamine component and the tetracarboxylic acid derivative are obtained. A method of reacting in an organic solvent can be employed. Such a reaction is advantageous in that it proceeds relatively easily in an organic solvent and the generation of by-products is extremely small.

  The organic solvent that can be used in the present embodiment is not particularly limited as long as the organic solvent that dissolves the generated polyamic acid is mainly used. Specific examples of the organic solvent capable of dissolving the polyamic acid include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethyl Sulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve , Ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate Ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol mono Acetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3 -Methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, Propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, acetic acid Propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, 3 Ethyl methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N , N-dimethylpropanamide, 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide and the like.

  These organic solvents can be used alone or in combination of two or more. The organic solvent is not limited to the above example, and a part of the solvent in which the polyamic acid does not dissolve may be mixed as long as the generated polyamic acid does not precipitate. Since water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the produced polyamic acid, it is preferable to use a dehydrated and dried organic solvent as much as possible.

  When the diamine component and the tetracarboxylic acid derivative are reacted in an organic solvent, for example, the solution in which the diamine component is dispersed and dissolved in the organic solvent is stirred, and the tetracarboxylic acid derivative is dispersed as it is or in the organic solvent. The method of adding after dissolving is mentioned. Conversely, a method of adding a diamine component to a solution in which a tetracarboxylic acid derivative is dispersed and dissolved in an organic solvent can also be mentioned. A method of alternately adding a diamine component and a tetracarboxylic acid derivative may be employed. When the diamine component or tetracarboxylic acid derivative is composed of a plurality of types of compounds, they may be reacted in a premixed state, or may be reacted individually and sequentially, and a low molecular weight product that has been reacted individually is mixed and reacted. It is good also as a high molecular weight body.

  The polymerization temperature when the diamine component and the tetracarboxylic acid derivative are reacted in an organic solvent can be selected from -20 ° C to 150 ° C, but is preferably in the range of -5 ° C to 100 ° C. . The reaction can be carried out at any concentration, but if the concentration is too low, it is difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring is difficult. Therefore, the total concentration of the tetracarboxylic acid derivative and the diamine component in the reaction solution is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The initial stage of the reaction is carried out at a high concentration, and then an organic solvent can be added.

  In the polyamic acid polymerization reaction, the ratio of the total number of moles of the tetracarboxylic acid derivative to the total number of moles of the diamine component is preferably 0.8 to 1.2. Similar to the normal polycondensation reaction, the closer the molar ratio is to 1.0, the higher the molecular weight of the polyamic acid produced.

  Examples of the method for imidizing the polyamic acid include thermal imidization in which a polyamic acid solution is heated as it is. The temperature at which the polyamic acid is thermally imidized in the solution is 100 ° C. to 400 ° C., preferably 120 ° C. to 250 ° C., and is preferably performed while removing water generated by the imidation reaction from the system.

  Moreover, as a method for imidizing a polyamic acid, catalytic imidation in which a catalyst is added to a polyamic acid solution can also be mentioned. The catalytic imidation of the polyamic acid can be performed by adding a basic catalyst and an acid anhydride to the polyamic acid solution and stirring at -20 to 250 ° C, preferably 0 to 180 ° C. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times of the amic acid group, and the amount of the acid anhydride is 1 to 50 mol times of the amido group, preferably 3 to 3 times. 30 mole times. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like. Among them, pyridine is preferable because it has an appropriate basicity for proceeding with the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Among them, use of acetic anhydride is preferable because purification after completion of the reaction is facilitated. The imidization rate by catalytic imidation can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

  Examples of the method for synthesizing the polyamic acid ester include a reaction between a tetracarboxylic acid diester dichloride and a diamine component, and a method of reacting the tetracarboxylic acid diester with a diamine component in the presence of an appropriate condensing agent and a base. Alternatively, it can also be obtained by polymerizing a polyamic acid in advance and esterifying the carboxylic acid in the amic acid using a polymer reaction.

  Specifically, tetracarboxylic acid diester dichloride and diamine in the presence of a base and an organic solvent are −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C., 30 minutes to 24 hours, preferably 1 to 4 hours. It can be synthesized by reacting.

  Pyridine, triethylamine and 4-dimethylaminopyridine can be used as the base here, but pyridine is preferable because the reaction proceeds gently. The addition amount of the base is preferably 2 to 4 times the molar amount of the tetracarboxylic acid diester dichloride from the viewpoint of easy removal and high molecular weight.

  When performing condensation polymerization in the presence of a condensing agent, triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N′-carbonyldiimidazole, dimethoxy-1, 3,5-triazinylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium, tetrafluoroborate, O- (benzotriazole-1 -Yl) -N, N, N ′, N′-tetramethyluronium hexafluorophosphate, diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate, 4- (4 6-dimethoxy-1,3,5-triazin-2-yl) 4-methoxymorpholium chloride-n-hydrate can be used. .

  In the method using the condensing agent, the reaction proceeds efficiently by adding Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The addition amount of the Lewis acid is preferably 0.1 to 1.0 times the molar amount of the tetracarboxylic acid diester.

  The solvent used for this reaction can be the solvent used when polymerizing the polyamic acid shown above, but N-methyl-2-pyrrolidone and γ-butyrolactone are preferred from the solubility of the monomer and polymer. May be used alone or in combination of two or more. The concentration at the time of synthesis is preferably 1 to 30% by mass and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is unlikely to occur and a high molecular weight body is easily obtained. Moreover, in order to prevent hydrolysis of tetracarboxylic acid diester dichloride, the solvent used for the synthesis of the polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent mixing of outside air in a nitrogen atmosphere.

  When recovering the produced polyamic acid, polyamic acid ester, and polyimide from the reaction solution, the reaction solution may be poured into a poor solvent and precipitated. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and water. The polymer precipitated in a poor solvent and collected by filtration can be dried by normal temperature or reduced pressure at room temperature or by heating. Moreover, when the polymer which carried out precipitation collection | recovery is re-dissolved in an organic solvent and the operation which carries out reprecipitation collection | recovery is repeated 2 to 10 times, the impurity in a polymer can be decreased. Examples of the poor solvent at this time include alcohols, ketones, and hydrocarbons, and it is preferable to use three or more kinds of poor solvents selected from these because purification efficiency is further improved.

  The molecular weight of the polyamic acid, polyamic acid ester, and polyimide in the present embodiment is determined by considering the strength of the coating film obtained when used as a liquid crystal aligning agent, workability during coating film formation, and uniformity of the coating film. The weight average molecular weight measured by the (Gel Permeation Chromatography) method is preferably 5,000 to 1,000,000, and more preferably 10,000 to 150,000.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of this embodiment is a coating liquid for forming a liquid crystal aligning film, and is a solution in which a polymer component for forming a polymer film is dissolved in an organic solvent. This polymer component contains at least one polymer selected from polyamic acid, polyamic acid ester, polyimide and polyamide obtained using a diamine component containing the diamine represented by the above formula [1]. 1-20 mass% is preferable, as for content of the polymer component which a liquid crystal aligning agent contains, More preferably, it is 3-15 mass%, Most preferably, it is 3-10 mass%.

  All of the polymer components may be the polymer of the present embodiment, or other polymers (polymers other than the polymer of the present embodiment) may be used alone or in combination of two or more. Good. In that case, content of the other polymer in a polymer component is 0.5-15 mass%, Preferably it is 1-10 mass%.

  For example, when the diamine component to be reacted with the tetracarboxylic acid derivative contains another diamine other than the diamine represented by the above formula [1], the other polymer is a polyamic acid obtained from the other diamine. , Polyamic acid ester, polyimide and the like.

  The organic solvent (solvent) used for the liquid crystal aligning agent of this invention will not be specifically limited if it is an organic solvent in which a polymer component is dissolved. Specific examples thereof include, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethyl Sulfoxide, tetramethylurea, pyridine, dimethylsulfone, γ-butyrolactone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, 4-hydroxy- - and methyl-2-pentanone. These may be used alone or in combination of two or more.

  The liquid crystal aligning agent of this embodiment may contain components other than the said polymer component. Examples thereof include solvents and compounds that improve the film thickness uniformity and surface smoothness when a liquid crystal aligning agent is applied, and compounds that improve the adhesion between the liquid crystal aligning film and the substrate.

  Specific examples of the solvent (poor solvent) that improves the uniformity of the film thickness and the surface smoothness include the following. Examples thereof are solvents having low surface tension, specifically isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl. Carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol , Diethylene glycol monoacetate, Ethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene , Propyl ether, dihexyl ether, 1-hexanol N-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, 3 -Methyl methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy 2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethylamine Ter-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n- Examples include butyl ester and isoamyl lactate.

  These poor solvents may be used alone or in combination of two or more. When using such a solvent, it is preferable that this solvent is 5-80 mass% of the whole solvent contained in a liquid crystal aligning agent, More preferably, it is 20-60 mass%.

  Examples of the compound that improves film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. More specifically, F-top EF301, EF303, EF352 (manufactured by Tochem Products), MegaFuck F171, F173, R-30 (manufactured by Dainippon Ink, Inc.), Florard FC430, FC431 (manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.). The use ratio of these surfactants is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the resin component contained in the liquid crystal aligning agent.

  Specific examples of the compound that improves the adhesion between the liquid crystal alignment film and the substrate include a functional silane-containing compound and an epoxy group-containing compound. For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-to Ethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltri Methoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-amino Propyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, 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-tetra Glycidyl-2,4-hexanediol, N, N, N ′, N ′,-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ', N',-tetraglycidyl-4,4'-diaminodiphenylmethane and the like. In addition to this, a predetermined phenoplast-based additive may be introduced for the purpose of preventing deterioration of electrical characteristics due to the backlight.

  When using the compound which improves adhesiveness with a board | substrate, it is preferable that the usage-amount is 0.1-30 mass parts with respect to 100 mass parts of the polymer component contained in a liquid crystal aligning agent, and more. Preferably it is 1-20 mass parts.

  In addition to the above, the liquid crystal aligning agent of the present embodiment is a dielectric or conductive material for the purpose of changing the electrical properties such as the dielectric constant and conductivity of the liquid crystal aligning film, as long as the gist of the present invention is not changed. Further, a crosslinkable compound for the purpose of increasing the hardness and density of the liquid crystal alignment film may be added.

  For example, the liquid crystal aligning agent is a group consisting of a crosslinkable compound having an epoxy group, an isocyanate group, an oxetane group or a cyclocarbonate group, a hydroxyl group, a hydroxyalkyl group, and a lower alkoxyalkyl group within a range not changing the gist of the present invention. A crosslinkable compound having at least one substituent selected from the above or a crosslinkable compound having a polymerizable unsaturated bond may be added. It is necessary to have two or more of these substituents and polymerizable unsaturated bonds in the crosslinkable compound.

  Examples of the crosslinkable compound having an epoxy group or an isocyanate group include bisphenolacetone glycidyl ether, phenol novolac epoxy resin, cresol novolac epoxy resin, triglycidyl isocyanurate, tetraglycidylaminodiphenylene, tetraglycidyl-m-xylenediamine, tetra Glycidyl-1,3-bis (aminoethyl) cyclohexane, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, bisphenol hexafluoroacetodiglycidyl ether, 1,3-bis (1- (2,3-epoxypropoxy)- 1-trifluoromethyl-2,2,2-trifluoromethyl) benzene, 4,4-bis (2,3-epoxypropoxy) octafluorobiphenyl, Liglycidyl-p-aminophenol, tetraglycidylmetaxylenediamine, 2- (4- (2,3-epoxypropoxy) phenyl) -2- (4- (1,1-bis (4- (2,3-epoxy) Propoxy) phenyl) ethyl) phenyl) propane or 1,3-bis (4- (1- (4- (2,3-epoxypropoxy) phenyl) -1- (4- (1- (4- (2,3 -Epoxypropoxy) phenyl) -1-methylethyl) phenyl) ethyl) phenoxy) -2-propanol.

  Examples of the crosslinkable compound having an oxetane group include crosslinkable compounds represented by formulas [4a] to [4k] published on pages 58 to 59 of International Publication No. WO2011 / 132751 (published 2011.10.27). Is mentioned.

  Examples of the crosslinkable compound having a cyclocarbonate group include formulas [5-1] to [5-42] described on pages 76 to 82 of International Publication WO2012 / 01132751 (2012.2.2 publication). The crosslinkable compound shown by these is mentioned.

  Examples of the crosslinkable compound having at least one substituent selected from the group consisting of a hydroxyl group and an alkoxyl group include an amino resin having a hydroxyl group or an alkoxyl group, such as a melamine resin, a urea resin, a guanamine resin, and a glycoluril. -Formaldehyde resins, succinylamide-formaldehyde resins or ethylene urea-formaldehyde resins. Specifically, a melamine derivative, a benzoguanamine derivative, or glycoluril in which a hydrogen atom of an amino group is substituted with a methylol group, an alkoxymethyl group, or both can be used. The melamine derivative or benzoguanamine derivative can exist as a dimer or a trimer. These preferably have an average of 3 to 6 methylol groups or alkoxymethyl groups per triazine ring.

  As an example of such a melamine derivative or a benzoguanamine derivative, MX-750 in which an average of 3.7 methoxymethyl groups is substituted per one triazine ring in a commercially available product, and an average of 5. methoxymethyl groups per one triazine ring. 8-substituted MW-30 (Sanwa Chemical Co., Ltd.) and Cymel 300, 301, 303, 350, 370, 771, 325, 327, 703, 712, etc., methoxymethylated melamine, Cymel 235, 236 Methoxymethylated butoxymethylated melamine such as 238, 212, 253, 254, butoxymethylated melamine such as Cymel 506, 508, carboxyl group-containing methoxymethylated isobutoxymethylated melamine such as Cymel 1141, Cymel 1123 and the like Methoxymethylated ethoxymethyl Benzoguanamine, methoxymethylated butoxymethylated benzoguanamine such as Cymel 1123-10, butoxymethylated benzoguanamine such as Cymel 1128, carboxyl group-containing methoxymethylated ethoxymethylated benzoguanamine such as Cymel 1125-80 (Mitsui Cyanamid Co., Ltd.) Manufactured). Examples of glycoluril include butoxymethylated glycoluril such as Cymel 1170, methylolated glycoluril such as Cymel 1172, and methoxymethylolated glycoluril such as Powderlink 1174.

  Examples of the benzene or phenolic compound having a hydroxyl group or an alkoxyl group include 1,3,5-tris (methoxymethyl) benzene, 1,2,4-tris (isopropoxymethyl) benzene, 1,4-bis ( sec-butoxymethyl) benzene or 2,6-dihydroxymethyl-p-tert-butylphenol.

  More specifically, International Publication WO2011 / 132751. (2011.10.27), pages 62 to 66, and the crosslinkable compounds represented by the formulas [6-1] to [6-48].

  Examples of the crosslinkable compound having a polymerizable unsaturated bond include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and tri (meth) acryloyloxyethoxytrimethylol. Crosslinkable compounds having three polymerizable unsaturated groups in the molecule such as propane or glycerin polyglycidyl ether poly (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (Meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol Di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide bisphenol A type di (meth) acrylate, propylene oxide bisphenol type di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin Di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, diglycidyl phthalate di (meth) acrylate or hydroxypivalic acid neo Crosslinkable compounds having two polymerizable unsaturated groups in the molecule such as pentyl glycol di (meth) acrylate, in addition to 2-hydroxyethyl (meth) acrylate, 2 Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, 3-chloro-2-hydroxy A crosslinkable compound having one polymerizable unsaturated group in the molecule such as propyl (meth) acrylate, glycerin mono (meth) acrylate, 2- (meth) acryloyloxyethyl phosphate ester or N-methylol (meth) acrylamide Can be mentioned.

  The said compound is an example of a crosslinkable compound, It is not limited to these. Moreover, the crosslinking | crosslinked compound used for a liquid crystal aligning agent may use 1 type individually or in combination of 2 or more types. The content of the crosslinkable compound in the liquid crystal aligning agent is preferably 0.1 to 150 parts by mass with respect to 100 parts by mass of all the polymer components. In order for the crosslinking reaction to proceed and to achieve the desired effect, 0.1 to 100 parts by weight is more preferable, and 1 to 50 parts by weight is most preferable, with respect to 100 parts by weight of all polymer components.

  In addition, as a compound that promotes charge transfer in the liquid crystal alignment film and promotes charge loss of a liquid crystal cell using the liquid crystal alignment film, International Publication No. WO2011-132751 (published 2011.10.27), pages 69 to 73. It is also preferable to add a nitrogen-containing heterocyclic amine compound represented by the formulas [M1] to [M156], which is shown on the page. This amine compound may be added directly to the composition, but it may be added after a solution having a concentration of 0.1% by mass to 10% by mass, preferably 1% by mass to 7% by mass, with a suitable solvent. preferable.

<Liquid crystal alignment film>
The liquid crystal aligning agent of the present embodiment can be used as a liquid crystal alignment film after being applied and baked on a substrate or the like and then subjected to alignment treatment by rubbing treatment, light irradiation or the like, or without alignment treatment in vertical alignment applications. In this case, the substrate to be used is not particularly limited as long as it is a highly transparent substrate, and a glass substrate or a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used. In addition, it is preferable to use a substrate on which an ITO (Indium Tin Oxide) electrode or the like for driving a liquid crystal is formed from the viewpoint of simplification of the process. Further, in the reflection type liquid crystal display element, an opaque material such as a silicon wafer can be used as long as the substrate is only on one side, and in this case, a material that reflects light such as aluminum can be used.

  A method for applying the liquid crystal aligning agent is not particularly limited, but industrially, a method of performing screen printing, offset printing, flexographic printing, inkjet, or the like is common. Other coating methods include dip, roll coater, slit coater, spinner and the like, and these may be used depending on the purpose.

  Firing after applying the liquid crystal aligning agent on the substrate can be performed at 50 to 300 ° C., preferably 80 to 250 ° C. by a heating means such as a hot plate, and the solvent can be evaporated to form a coating film. Since the diamine represented by the formula [1] has both an amide bond (—NHCO—) and a carboxyl group (—COOH) in the side chain, the amide bond—amide bond, amide bond—carboxyl group, carboxyl group—carboxyl Due to the interaction between the partial structures such as groups, the structure of the polymer after baking becomes an electrochemically active structure. For this reason, it is possible to obtain a liquid crystal alignment film that can ensure good liquid crystal alignment properties, has excellent voltage holding characteristics, and is difficult to accumulate residual voltage and can suppress image sticking. If the thickness of the coating film formed after baking is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may be lowered. Preferably it is 10-100 nm. When the liquid crystal is aligned horizontally or tilted, the fired coating film is treated by rubbing or irradiation with polarized ultraviolet rays.

<Liquid crystal display element>
The liquid crystal display element of the present embodiment is a liquid crystal display element obtained by obtaining a substrate with a liquid crystal alignment film from the liquid crystal aligning agent of the present embodiment by the method described above, and then producing a liquid crystal cell by a known method. For example, the two substrates disposed so as to face each other, the liquid crystal layer provided between the substrates, and the liquid crystal aligning agent of the present invention provided between the substrate and the liquid crystal layer. A liquid crystal display device comprising a liquid crystal cell having a liquid crystal alignment film.

  As a liquid crystal cell manufacturing method, a pair of substrates on which a liquid crystal alignment film is formed are prepared, spacers are scattered on the liquid crystal alignment film of one substrate, and the liquid crystal alignment film surface is on the inside, Examples include a method in which substrates are bonded together and liquid crystal is injected under reduced pressure, or a method in which liquid crystal is dropped onto a liquid crystal alignment film surface on which spacers are dispersed and then a substrate is bonded and sealed. The thickness of the spacer at this time is preferably 1 to 30 μm, more preferably 2 to 10 μm.

  Examples of the liquid crystal include positive liquid crystal having positive dielectric anisotropy and negative liquid crystal having negative dielectric anisotropy, specifically, for example, MLC-2003, MLC-6608, MLC-6609 manufactured by Merck & Co., Inc. Etc. can be used.

  As described above, the liquid crystal display device produced using the liquid crystal aligning agent of the present invention can ensure good liquid crystal alignment, has excellent voltage holding characteristics, and can suppress image sticking. Therefore, it can be suitably used for large-screen liquid crystal televisions, high-definition mobile applications, in-vehicle applications in high-temperature environments, and the like.

  EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is limited to these and is not interpreted. The following abbreviations may be used in this example column.

<Tetracarboxylic acid derivative>
CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride PMDA: pyromellitic dianhydride BODA: bicyclo [3.3.0] octane-2,4,6,8-tetracarboxylic dianhydride 1,3-DMCBDE-Cl: tetracarboxylic acid dialkyl ester dihalide compound of the following formula

<Other diamines (diamines other than those represented by the above formula [1])>
DABA: 4,4′-diaminobenzanilide DBA: 3,5-diaminobenzoic acid Me-4AphA: N-methyl-2- (4-aminophenyl) ethylamine (also referred to as “4-amino-N-methylphenethylamine”) )
DADPA: 4,4′-diaminodiphenylamine DDE: 4,4′-diaminodiphenyl ether DA-2MG: 1,2-bis (4-aminophenoxy) ethane

<Organic solvent>
NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: Butyl cellosolve

<Synthesis of diamine represented by the above formula [1]>
(Synthesis Example 1)
Diamine [DA1] was synthesized by the following reaction.

That is, γ-aminobutyric acid methyl ester hydrochloride (22.1 g, 144 mmol) in acetonitrile (132 g) was mixed with N, N′-dimethylaminopyridine (0.880 g, 7.20 mmol) and triethylamine (35.0 g, 346 mmol). And the reaction mixture was cooled in an ice bath. To the mixture, an acetonitrile solution (60 g) of 3,5-dinitrobenzoic acid chloride (30.2 g, 131 mmol) was added dropwise, and the mixture was warmed to room temperature and stirred for about 2 hours. Filtration of this mixture gave a filtrate from which solids had been removed, and the solvent was distilled off under reduced pressure. The obtained residue was subjected to liquid separation extraction with ethyl acetate and water, and the separated organic layer was concentrated to obtain a crude product containing a dinitro compound [DN1]. The obtained crude product was used for the next reaction without purification. The ¹ H-NMR measurement result of the obtained dinitro compound [DN1] is shown below.

¹ H-NMR (CDCl3): δ 9.17 (t, 1H, J = 2.0 Hz), 9.02 (d, 2H, J = 2.0 Hz), 7.62 (bs, 1H, -C (O) NH-), 3.77 (s, 3H, -CO2CH3), 3.59 (dt, 2H, J = 5.2, 6.4Hz, -NHCH2-), 2.58 (t, 2H, J = 6.4Hz, -CH2CO2Me), 2.08-2.00 (m, 2H) .

The crude product containing the dinitro compound [DN1] obtained by the above reaction was dissolved in methanol (122 g), and water (41 g) was further added. To the mixture was added lithium hydroxide monohydrate (9.34 g, 223 mmol), and the mixture was stirred at room temperature for 24 hours. After completion of the reaction, the reaction mixture was acidified with hydrochloric acid to make the dinitro compound [DN1] free solid and separated by filtration. The filtrate was dried to obtain a dinitro compound [DN2] (29.7 g, 76% yield (two steps)). The ¹ H-NMR measurement result of the obtained dinitro compound [DN2] is shown below.

¹ H-NMR (DMSO-d6): δ12.1 (bs, 1H, -CO2H), 9.23 (t, 1H, J = 5.6 Hz, C (O) NH-), 9.06 (d, 2H, J = 2.0 Hz), 8.95 (t, 1H, J = 2.0Hz), 3.36 (dt, 2H, J = 5.6, 6.8Hz, -NHCH2-), 2.31 (t, 2H, J = 7.2Hz, -CH2CO2H), 1.85- 1.74 (m, 2H).

Palladium activated carbon (3.39 g) was added to a THF solution (272 g) of a dinitro compound ([DN2]; 34.0 g, 114 mmol), and the mixture was stirred at room temperature for 4 days in a hydrogen atmosphere. The palladium activated carbon was removed from the reaction solution by filtration, and the solvent was distilled off under reduced pressure. The obtained residue was dissolved in methanol, activated carbon was added and stirred for 30 minutes, and then the reaction solution was filtered to separate the activated carbon. The filtrate was concentrated and dried to obtain the objective diamine [DA1] as a purple solid (19.1 g, 70% yield). The ¹ H-NMR measurement result of the obtained diamine [DA1] is shown below.

¹ H-NMR (DMSO-d6): δ 8.03 (t, 1H, J = 5.6Hz, -C (O) NH-), 6.19 (d, 2H, J = 2.0Hz), 5.92 (t, 1H, J = 2.0Hz), 5.15-4.55 (b, 4H, -NH2x2), 3.20-3.12 (m, 2H, -NHCH2-), 2.22 (t, 2H, J = 7.6Hz, -CH2CO2H), 1.78-1.64 ( m, 2H).

(Synthesis Example 2)
Diamine [DA2] was synthesized by the following reaction.

That is, β-alanine ethyl ester hydrochloride (30.0 g, 195 mmol) was suspended in acetonitrile (180 g), triethylamine (43.1 g, 426 mmol) and 4- (N, N-dimethylamino) pyridine (650 mg, 5.32 mmol), and the mixture was stirred for 30 minutes and then cooled to 3 ° C. Then, a solution of 3,5-dinitrobenzoyl chloride (40.9 g, 195 mmol) in acetonitrile (81.0 g) was added dropwise over 35 minutes. Thereafter, after stirring at 25 ° C. for 19 hours, the precipitated solid was removed by filtration, the filtrate was washed with acetonitrile (60.0 g), and the filtrate was concentrated. Next, ethyl acetate (300 g) and water (100 g) are added to the residue after concentration, followed by addition of potassium carbonate (4.81 g, 35.5 mmol), and the organic phase is separated and washed with water (100 g). Washed twice. Thereafter, the organic phase was concentrated and dried to obtain a crude dinitro compound [DN3] as a reddish brown solid (yield 57.8 g, yield 108%). The ¹ H-NMR measurement result of the obtained dinitro compound [DN3] is shown below.

¹ H-NMR (CDCl3): δ 9.18 (t, J = 2.2Hz, 1H, C6H3 (NO2) 2), 8.94 (d, J = 2.2Hz, 2H, C6H3 (NO2) 2), 7.22 (br, 1H, NH), 4.12 (q, J = 7.2Hz, 2H, CH2CH3), 3.80 (dt, J = 6.4, 5.8Hz, 2H, NHCH2CH2), 2.70 (t, J = 5.8Hz, 2H, CH2C (O) ), 1.30 (t, J = 7.2Hz, 3H, CH3).

The dinitro compound ([DN3]; 55.2 g, 177 mmol) obtained by the above reaction was suspended in methanol (110 g). A solution prepared by dissolving lithium hydroxide (12.7 g) in water (55.0 g) was added to this suspension at 25 ° C., and stirred for 3 hours. Then, 3 mol / L hydrochloric acid (130 mL) was added, and the mixture was stirred for 10 minutes. Stir. Thereafter, the precipitate was filtered, and the solid was washed three times with water (50 g). This solid was dried and stirred with a mixed solution of 2-propanol (100 g) and hexane (200 g) at 40 ° C. for 30 minutes, and then the solid was filtered and dried to obtain a dinitro compound [DN4] as a yellow solid. (Yield 43.9 g, Yield 87% (2 steps)). The ¹ H-NMR measurement result of the obtained dinitro compound [DN4] is shown below.

¹ H-NMR (DMSO-d6): δ 9.18 (t, J = 2.2Hz, 1H, C6H3 (NO2) 2), 8.94 (d, J = 2.2Hz, 2H, C6H3 (NO2) 2), 7.22 ( br, 1H, NH), 4.12 (q, J = 7.2Hz, 2H, CH2CH3), 3.80 (dt, J = 6.4, 5.8Hz, 2H, NHCH2CH2), 2.70 (t, J = 5.8Hz, 2H, CH2C ( O)), 1.30 (t, J = 7.2Hz, 3H, CH3).

The dinitro compound ([DN4]; 40.8 g) obtained by the above reaction was suspended in methanol (326 g), 5% palladium-supported carbon (55% water-containing product, 4.0 g) was added, and the system was hydrogenated. And stirred at 25 ° C. for 21 hours. Thereafter, water (80.0 g) was added, 5% palladium-supported carbon was removed by filtration, and the filtrate was concentrated and dried. Next, methanol (64.4 g) was added to the residue, and the mixture was stirred at 60 ° C. for 2 hours and then cooled to 25 ° C. The solid was filtered, washed twice with a mixed solution of toluene / methanol (2/1) (40 mL), and dried to obtain the target diamine [DA2] as a purple solid (24. 8 g, yield 77%). The ¹ H-NMR measurement result of the obtained diamine [DA2] is shown below.

¹ H-NMR (DMSO-d6): δ 7.98 (t, J = 5.4Hz, 1H, NH), 6.18 (d, J = 2.0Hz, 1H, C6H3 (NH2) 2), 5.92 (t, J = 2.2Hz, 2H, C6H3 (NH2) ₂ ), 4.85 (br, 5H, NH2andCO2H), 3.35 (m, 2H, NHCH2CH2), 2.44 (t, J = 7.2Hz, 2H, CH2C (O)).

(Synthesis Example 3)
Diamine [DA3] was synthesized by the following reaction.

That is, triethylamine (24.3 g, 240 mmol) was added to a suspension of glutamic acid dibenzyl ester hydrochloride (36.4 g, 100 mmol) and acetonitrile (218 g), stirred for 30 minutes, and then cooled to 2 ° C. Then, a solution of 3,5-dinitrobenzoyl chloride (23.7 g, 103 mmol) in acetonitrile (47 g) was added dropwise over 20 minutes. After stirring this reaction mixture for 3 hours, the precipitated solid was removed by filtration, the filtrate was washed 3 times with acetonitrile (30 g), and the filtrate was concentrated. Ethyl acetate (360 g) and water (52 g) were added to the residue for liquid separation, the organic phase was separated, and further washed twice with water (52 g). The organic phase was concentrated, ethyl acetate (52 g) was added to the residue and heated to 55 ° C., hexane (208 g) was added to precipitate a solid, and the mixture was cooled to 25 ° C. The precipitate was filtered, and the obtained solid was washed twice with a mixed solution (50 mL) of hexane / ethyl acetate (4/1) and dried to obtain a dinitro compound [DN5] as a white solid. (Yield 49.9 g, yield 96%). The ¹ H-NMR measurement result of the obtained dinitro compound [DN5] is shown below.

¹ H-NMR (CDCl3): δ 9.17 (t, J = 2.0Hz, 1H, C6H3 (NO2) 2), 9.01 (d, J = 2.0Hz, 2H, C6H3 (NO2) 2), 8.07 (d, J = 6.8, 1H, NH), 7.37-7.26 (m, 10H, 2Ph), 5.27-5.14 (m, 4H, CH2Ph), 4.80-4.78 (m, 1H, NHCH2), 2.64-2.50 (m, 2H, CH2C (O)), 2.38-2.21 (m, 2H, CHCH2CH2).

The dinitro compound ([DN5]; 43.7 g, 83.8 mmol) obtained by the above reaction was dissolved in DMF (175 g), and 5% palladium-supported carbon (53% water-containing product, 1.31 g) was added to the system. The inside was replaced with hydrogen and stirred at 50 ° C. for 6 hours. Thereafter, this solution was filtered, the filtrate was washed twice with DMF (10 g), and the filtrate was concentrated and dried. Methanol (71 g) was added to the residue, and the mixture was stirred at 60 ° C. for 1 hour. Toluene (71 g) was added, and the precipitated solid was filtered. Furthermore, it was washed twice with a mixed solution (40 mL) of toluene / methanol (1/1, v / v) and dried to obtain the target diamine [DA3] as a purple solid (yield 23.0 g). , Yield 93%). The ¹ H-NMR measurement result of the obtained diamine [DA3] is shown below.

¹ H-NMR (DMSO-d6): δ8.11 (d, J = 7.6, 1H, NH), 6.24 (d, J = 2.0Hz, 1H, C6H3 (NH2) 2), 5.94 (t, J = 2.0 Hz, 2H, C6H3 (NH2) 2), 4.31 (ddd, J = 7.6, 4.8, 2.0Hz, 1H, NHCH 2), 2.31 (dd, J = 7.6, 7.2Hz, 2H, CH2C (O)), 2.07 -1.88 (m, 2H, CHCH2CH2).

<Production of polymer / liquid crystal aligning agent>
(Synthesis Example 4)
1.85 g (8.30 mmol) of diamine [DA1] produced in Synthesis Example 1 and 28.3 g of NMP were added to a 50 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, and dissolved by stirring while feeding nitrogen. I let you. While stirring this diamine solution, 1.72 g (7.89 mmol) of PMDA was added, NMP was further added so that the solid content concentration was 10% by mass, and the mixture was stirred at room temperature for 2 hours in a nitrogen atmosphere. This obtained the solution of the polyamic acid (PAA-1) as a polymer. It was 22.9 mPa * s when the viscosity at 25 degrees C of this polyamic acid solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.). The number average molecular weight of this polyamic acid was 6,782, and the weight average molecular weight was 20,520.

  NMP 8.01g and BCS 8.01g were added to this polyamic acid solution 24.0g, and the liquid crystal aligning agent whose density | concentration of polyamic acid (PAA-1) was 6.0 mass% was obtained.

(Synthesis Example 5)
1.85 g (8.30 mmol) of diamine [DA2] produced in Synthesis Example 2 and 28.3 g of NMP were added to a 50 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, and dissolved by stirring while feeding nitrogen. I let you. While stirring this diamine solution, 1.72 g (7.89 mmol) of PMDA was added, NMP was further added so that the solid content concentration was 10% by mass, and the mixture was stirred at room temperature for 2 hours in a nitrogen atmosphere. Thereby, the solution of the polyamic acid (PAA-2) as a polymer was obtained. It was 29.0 mPa * s when the viscosity at 25 degrees C of this polyamic acid solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.). The number average molecular weight of this polyamic acid was 9,714, and the weight average molecular weight was 20,072.

  NMP 8.02g and BCS 8.00g were added to this polyamic acid solution 24.1g, and the liquid crystal aligning agent whose density | concentration of polyamic acid (PAA-2) was 6.0 mass% was obtained.

(Synthesis Example 6)
Add 2.33 g (8.30 mmol) of the diamine [DA3] prepared in Synthesis Example 3 above and 28.8 g of NMP to a 50 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, and dissolve by stirring while feeding nitrogen. I let you. While stirring this diamine solution, 1.72 g (7.89 mmol) of PMDA was added, NMP was further added so that the solid content concentration was 10% by mass, and the mixture was stirred at room temperature for 2 hours in a nitrogen atmosphere. Thereby, the solution of the polyamic acid (PAA-3) as a polymer was obtained. It was 33.7 mPa * s when the viscosity at 25 degrees C of this polyamic acid solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company). The number average molecular weight of this polyamic acid was 10,526, and the weight average molecular weight was 23,704.

  NMP9.94g and BCS6.54g were added to 16.24g of this polyamic acid solution, and the liquid crystal aligning agent whose density | concentration of polyamic acid (PAA-3) was 6.0 mass% was obtained.

(Synthesis Example 7)
In a 50 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 1.11 g (4.98 mmol) of [DA1] produced in Synthesis Example 1 above, 0.50 g (3.32 mmol) of Me-4APhA, NMP28 .3 g was added and dissolved by stirring while feeding nitrogen. While stirring the diamine solution, 0.93 g (4.73 mmol) of CBDA and 0.69 g (3.16 mmol) of PMDA were added, and NMP was further added so that the solid content concentration was 10% by mass. The solution was stirred for 2 hours to obtain a polyamic acid (PAA-4) solution. It was 103 mPa * s when the viscosity at 25 degrees C of this polyamic acid solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.). The number average molecular weight of this polyamic acid was 10,500, and the weight average molecular weight was 23,100.

  NMP 8.01g and BCS 8.01g were added to this polyamic acid solution 24.0g, and the liquid crystal aligning agent whose density | concentration of polyamic acid (PAA-4) is 6.0 mass% was obtained.

(Synthesis Example 8)
In a 50 mL four-necked flask equipped with a stirrer and a nitrogen introducing tube, 0.74 g (3.32 mmol) of [DA1] prepared in Synthesis Example 1 above, 0.33 g (1.66 mmol) of DADPA, and 0 DDE were prepared. .66 g (3.32 mmol) was taken, NMP (12.0 g) was added, and dissolved by stirring while feeding nitrogen. While stirring the diamine solution, 1.48 g (5.91 mmol) of BODA was added and stirred at 25 ° C. for 2 hours. Next, 0.38 g (1.97 mmol) of CBDA and NMP were added so that the solid concentration was 10% by mass, and the mixture was stirred at 25 ° C. for 4 hours to obtain a polyamic acid solution (PAA-5). It was 120 mPa * s when the viscosity at 25 degrees C of this polyamic acid solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.). The number average molecular weight of this polyamic acid was 11,300, and the weight average molecular weight was 27,100.

  To 10.0 g of the resulting polyamic acid solution, NMP was added to dilute to 5% by mass, and then acetic anhydride (2.24 g) and pyridine (0.87 g) were added as an imidization catalyst and reacted at 50 ° C. for 2 hours. It was. This reaction solution was put into methanol (150 ml), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C. to obtain a polyimide powder. The imidation ratio of this polyimide was 50%, the number average molecular weight was 24,800, and the weight average molecular weight was 88,000.

  NMP29.6g and BCS8.00g were added to this polyimide powder 2.40g, and the liquid crystal aligning agent whose density | concentration of a polyimide (SPI-1) is 6.0 mass% was obtained.

(Synthesis Example 9)
A 500 mL four-necked flask with a stirrer was placed in a nitrogen atmosphere, 0.74 g (3.36 mmol) of [DA1] produced in Synthesis Example 1 was taken, and 1.21 g (4.94 mmol) of DA-2MG was taken. NMP (111 g) and pyridine (6.18 g) were added and dissolved by stirring. Next, while stirring this diamine solution, 2.56 g (7.88 mmol) of 1,3-DMCBDE-Cl was added and reacted at 15 ° C. for 15 hours. The obtained polyamic acid alkyl ester solution was poured into water (1230 g) while stirring, and the precipitated white precipitate was collected by filtration, washed 5 times with IPA (isopropyl alcohol) (1230 g), and dried. 3.55 g of white polyamic acid alkyl ester powder was obtained. The number average molecular weight of this polyamic acid alkyl ester was 15,200, and the weight average molecular weight was 31,000.

  2.40 g of this polyamic acid alkyl ester powder is taken in a 100 mL Erlenmeyer flask, 29.6 g of NMP and 8.00 g of BCS are added, and the mixture is stirred and dissolved at 25 ° C. for 24 hours. The solid content concentration is 6.0% by mass. A polyamic acid alkyl ester solution (PAE-1) was prepared, and a liquid crystal aligning agent containing the same was obtained.

(Comparative Synthesis Example 1)
Basically, Synthesis Example 4 is used except that the diamine represented by the above formula [1] is not used and another diamine (a diamine other than the diamine represented by the above formula [1]) is used instead. A polymer / liquid crystal aligning agent was prepared in the same manner.

  That is, 1.89 g (8.30 mmol) of DABA as another diamine and 28.3 g of NMP were added to a 50 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 1.72 g (7.89 mmol) of PMDA was added, NMP was further added so that the solid content concentration was 10% by mass, and the mixture was stirred at room temperature for 2 hours in a nitrogen atmosphere. Thereby, a solution of polyamic acid (PAA-5) as a comparative polymer was obtained. It was 2357 mPa * s when the viscosity at 25 degrees C of this polyamic acid solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.). The number average molecular weight of this polyamic acid was 20,145, and the weight average molecular weight was 49,422.

  NMP 8.01g and BCS 8.01g were added to 24.0g of this polyamic acid solution, and the liquid crystal aligning agent for a comparison whose concentration of polyamic acid was 6.0 mass% was obtained.

(Comparative Synthesis Example 2)
In the same manner as in Comparative Synthesis Example 1, a polymer / liquid crystal aligning agent was prepared using other diamines instead of the diamine represented by the formula [1].

  That is, 1.26 g (8.30 mmol) of DBA as another diamine and 28.3 g of NMP were added to a 50 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 1.72 g (7.89 mmol) of PMDA was added, NMP was further added so that the solid content concentration was 10% by mass, and the mixture was stirred at room temperature for 2 hours in a nitrogen atmosphere. Thereby, a solution of polyamic acid (PAA-6) as a comparative polymer was obtained. It was 88.3 mPa * s when the viscosity at 25 degrees C of this polyamic acid solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.). The number average molecular weight of this polyamic acid was 14,239, and the weight average molecular weight was 37,153.

  NMP 8.01g and BCS 8.01g were added to 24.0g of this polyamic acid solution, and the liquid crystal aligning agent for a comparison whose concentration of polyamic acid was 6.0 mass% was obtained.

  Table 2 summarizes the liquid crystal aligning agents of Synthesis Examples 4 to 9 described above and the comparative liquid crystal aligning agents of Comparative Synthesis Examples 1 and 2.

<Measurement of molecular weight of polymer>
The molecular weights of the polymers obtained in Synthesis Examples 4 to 9 and the comparative polymers obtained in Comparative Synthesis Examples 1 and 2 are room temperature gel permeation chromatography (GPC) equipment (GPC-101) (manufactured by Showa Denko KK). ) And a column (KD-803, KD-805) (manufactured by Shodex) under the following conditions.
-Column temperature: 50 ° C
Eluent: N, N′-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H ₂ O) is 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) is 30 mmol / L , THF is 10 ml / L)
・ Flow rate: 1.0 ml / min
Standard sample for creating calibration curve: TSK
Standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000 and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: about 12,000, 4,000 and 1,000) (polymer) Manufactured by Laboratory).

<Production of liquid crystal cell>
(Examples 1-6)
Using the liquid crystal aligning agents obtained in Synthesis Examples 4 to 9, liquid crystal cells were produced by the following methods. The physical properties (characteristics) of the liquid crystal alignment treatment agents in these synthesis examples are shown in Table 3 described later.

  That is, after the liquid crystal aligning agent is filtered through a 1.0 μm filter, it is spin-coated on a glass substrate with a transparent electrode, dried on a hot plate at 80 ° C. for 5 minutes, and baked at 230 ° C. for 20 minutes to have a film thickness of 100 nm. A liquid crystal alignment film (polyimide film) was obtained. After rubbing this polyimide film with a rayon cloth (roll diameter 120 mm, rotation speed 1000 rpm, moving speed 20 mm / sec, pushing amount 0.4 mm), ultrasonic irradiation was performed in pure water for 1 minute, and 80 ° C. for 10 minutes. Dried. Two substrates with such a liquid crystal alignment film are prepared, and a 6 μm spacer is placed on the liquid crystal alignment film surface of one of the substrates, and then combined so that the rubbing directions of the two substrates are antiparallel to each other. The periphery was sealed, and an empty cell with a cell gap of 6 μm was produced. Liquid crystal (MLC-2041, manufactured by Merck & Co., Inc.) was vacuum-injected into this cell at room temperature, and the inlet was sealed to obtain an anti-parallel liquid crystal cell.

(Comparative Examples 1-2)
Using the comparative liquid crystal aligning agents obtained in Comparative Synthesis Examples 1 and 2 described above, comparative liquid crystal cells were produced in the same manner as in Examples 1 to 6, respectively. The physical properties (characteristics) of the liquid crystal aligning agents of these comparative synthesis examples are shown in Table 3 described later.

<Evaluation of liquid crystal alignment>
The initial alignment of the liquid crystal cells prepared in Examples 1 to 6 and the comparative liquid crystal cells prepared in Comparative Examples 1 and 2 was visually observed. Evaluation was performed as follows. The results are shown in Table 3.
○: Oriented well.
X: Many light omissions and poor alignment positions are observed.

<Evaluation of voltage holding characteristics>
By applying a voltage of 4 V for 60 μs and measuring the voltage after 16.67 ms for the liquid crystal cells prepared in Examples 1 to 6 and the comparative liquid crystal cells prepared in Comparative Examples 1 and 2, The variation from the value was calculated as the voltage holding ratio (%). During the measurement, the temperature of the liquid crystal cell was set to 23 ° C., 60 ° C., and 90 ° C., and the measurement was performed at each temperature. It can be said that the higher the voltage holding ratio can be maintained with respect to the temperature rise, the better the voltage holding characteristics. For measurement of the voltage holding ratio, a VHR-1 voltage holding ratio measuring device manufactured by Toyo Technica Co., Ltd. was used. The results are shown in Table 3.

<Measurement of residual voltage by dielectric absorption method>
About the liquid crystal cell produced in the said Examples 1-6 and the liquid crystal cell for comparison produced in the said Comparative Examples 1-2, the residual voltage was measured by the dielectric absorption method using the liquid-crystal physical property evaluation apparatus 6254 type made from Toyo Technica. It was. Measurement conditions were as follows: a direct current of 10 V was applied to the liquid crystal cell for 30 minutes, a short-circuit was performed for 1 second, a potential difference was observed for 20 minutes, and the maximum residual voltage (mV) and the minimum residual voltage (mV) were described. The measurement temperature is 60 ° C. It can be said that the smaller this value, the better the electrical characteristics. The results are shown in Table 3.

  As described above, as shown in Table 3, a liquid crystal alignment film was prepared from the liquid crystal alignment agents obtained in Synthesis Examples 4 to 9, and according to the liquid crystal cells (Examples 1 to 6) obtained thereby, the comparative liquid crystal Compared to the cells (Comparative Examples 1 and 2), it was confirmed that light leakage and alignment failure can be prevented, and thus good liquid crystal alignment can be secured.

  Moreover, as shown in Table 3, according to the liquid crystal cell (Examples 1 to 6), the voltage holding ratio is maintained at a high value with respect to the temperature rise as compared with the comparative liquid crystal cell (Comparative Examples 1 and 2). Therefore, it was confirmed that the voltage holding characteristics were excellent.

Furthermore, as shown in Table 3, according to the liquid crystal cells (Examples 1 to 6), the maximum residual voltage (mV) and the minimum residual voltage (mV) compared to the comparative liquid crystal cells (Comparative Examples 1 and 2). ), And therefore, it was confirmed that the accumulation of residual voltage can be suppressed. In particular, in the diamine represented by the formula [1], R ₁ is an alkylene group formed of 1 to 3 carbon atoms, and the hydrogen atom bonded to the carbon atom contained in R ₁ is substituted with a carboxyl group. When a liquid crystal aligning agent is produced using the same (Synthesis Example 6) and used as a liquid crystal cell (Example 3), it is possible to suppress the accumulation of residual voltage compared to other examples. confirmed. That is, according to the liquid crystal cells of Examples 1 to 3, it was found that image sticking can be suppressed, and the effect is particularly remarkable in Example 3.

Claims (7)

A polyamic acid obtained by reacting a diamine component containing a diamine represented by the following formula [1] with a tetracarboxylic acid derivative, a polyamic acid ester, or the polyamic acid and / or polyamic acid ester is dehydrated and closed (imide) A polymer comprising a polyimide obtained by

(In the formula, R ₁ is an ether bond, a thioether bond, an amide bond, or an alkylene group, alkenyl group, alkynyl group, alicyclic hydrocarbon and aromatic hydrocarbon formed of 1 to 10 carbon atoms. When R ₁ contains a carbon atom, the hydrogen atom bonded to the carbon atom is at least one selected from the group consisting of a halogen atom, a halogen-containing alkyl group, a hydroxyl group, and a carboxyl group. May be substituted.) In the formula [1], R ₁ is an alkylene group having 1 to 3 carbon atoms, and the hydrogen atom bonded to the carbon atom contained in R ₁ may be substituted with a carboxyl group. The polymer according to claim 1. The diamine represented by the formula [1] is at least one diamine selected from the group represented by the following formulas [DA1] to [DA3]. Coalescence.

  The polymer according to any one of claims 1 to 3, wherein the diamine component contains 5 mol% or more of the diamine represented by the formula [1].   A liquid crystal aligning agent comprising the polymer according to claim 1.   A liquid crystal alignment film comprising the liquid crystal alignment agent according to claim 5.   A liquid crystal display element comprising the liquid crystal alignment film according to claim 6.