JP2013228672A - Liquid crystal aligning agent, liquid crystal alignment layer, liquid crystal display element, polymer, and compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal aligning agent capable of exhibiting excellent liquid crystal alignment properties and light fastness, and also forming a coating film with good detachability from a substrate.SOLUTION: A liquid crystal aligning agent contains at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, polyimide and polyorganosiloxane, and contains, as the polymer, a polymer (P1) having a group represented by following formula (0).

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal aligning film, a liquid crystal display element, a polymer, and a compound, and particularly relates to a liquid crystal aligning agent that can be suitably used for manufacturing a vertical alignment type liquid crystal display element.

  Conventionally, as a liquid crystal display element, various drive systems having different electrode structures and physical properties of liquid crystal molecules to be used have been developed. For example, TN type, STN type, VA type, MVA type, in-plane switching type (IPS type) ), FFS type, optical compensation bend type (OCB type) and other various liquid crystal display elements are known. These liquid crystal display elements have a liquid crystal alignment film for aligning liquid crystal molecules. As the material for the liquid crystal alignment film, polymers such as polyamic acid, polyimide, polyamic acid ester, polyester, and polyorganosiloxane are used. Among them, various properties such as heat resistance, mechanical strength, and affinity with liquid crystal are good. Therefore, polyamic acid and polyimide are generally used.

  One of the characteristics required for the liquid crystal alignment film is that a desired pretilt angle according to the driving method can be expressed. For example, when applied to a vertical alignment type liquid crystal display element such as a VA type or an MVA type. Therefore, it is required that a high pretilt angle (for example, a pretilt angle of 87 degrees or more) can be expressed. In addition, as a method for controlling the alignment of liquid crystal molecules by a liquid crystal alignment film, conventionally, a long-chain alkyl group or a steroid skeleton is introduced into the side chain of a polymer component contained in a liquid crystal aligning agent, or a phenylene group or a cyclohexyl group. It has been proposed to introduce a structure in which a plurality of cyclic groups such as those are connected (for example, see Patent Documents 1 to 3).

  By the way, in recent years, liquid crystal display elements are used not only for conventional small display terminals such as personal computers, but also for large display devices such as large-screen liquid crystal televisions and information displays. . In addition, as the size of the substrate increases due to the expansion of applications, a liquid crystal dropping method (ODF method) is attracting attention as a manufacturing technique of a liquid crystal display element. The ODF method is a method in which liquid crystal molecules are dropped on one of a pair of substrates on which a liquid crystal alignment film is formed and the other substrate is bonded in a vacuum to fill the entire surface with liquid crystal molecules. is there. According to this method, there is an advantage that the process time of the liquid crystal filling process can be greatly shortened as compared with the conventionally used vacuum injection method.

International Publication No. 2008/117759 International Publication No. 2008/117760 JP 2001-305549 A

  The ODF method has the above-mentioned merits, but when a vertical alignment type liquid crystal display element is manufactured, display unevenness called “ODF unevenness” is likely to occur, and the display quality of the liquid crystal display element may be deteriorated. Such display unevenness is considered to be caused by insufficient alignment performance of liquid crystal molecules by the liquid crystal alignment film. Therefore, in order to improve the display quality of the liquid crystal display element even when the ODF method is adopted, a liquid crystal alignment film that can exhibit liquid crystal alignment superior to that of the conventional one is required.

  Moreover, in the manufacturing process of a liquid crystal aligning film, defects, such as a pinhole and a coating film nonuniformity, may arise in the coating film formed on the board | substrate using the liquid crystal aligning agent. When a defect occurs in the coating film, the coating film may be peeled off from the substrate and the substrate may be reused. With such rework, the coating film can be easily peeled off from the substrate (good peelability). Is required.

  The operating principles of various liquid crystal display elements are broadly divided into transmission types and reflection types. Among these, in the transmissive type, since the display is performed by the backlight light source from the back surface of the element, the liquid crystal alignment film is exposed to the light from the backlight light source for a long time. On the other hand, the reflective type does not use a backlight light source, and displays with reflected light from the outside such as sunlight, so it has the advantage of lower power consumption than the transmissive type, but is exposed to strong ultraviolet rays. Will be. Therefore, the liquid crystal display element is required to have excellent light resistance in any operating principle.

  The present invention has been made in view of the above problems, and mainly provides a liquid crystal aligning agent that can express excellent liquid crystal alignment properties and can form a coating film having excellent peelability and light resistance to a substrate. Objective. Another object of the present invention is to provide a liquid crystal alignment film having excellent liquid crystal alignment properties, light resistance, and good peelability to a substrate, and a liquid crystal display device including the liquid crystal alignment film.

  As a result of intensive studies to achieve the above-described problems of the prior art, the present inventors include a polymer having a specific structure in the side chain as at least a part of the polymer contained in the liquid crystal aligning agent. Thus, the present inventors have found that the above problems can be solved, and have completed the present invention. Specifically, the present invention provides the following liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element, and compounds and polymers used for the production thereof.

（式（０）中、Ａｃ^１及びＡｃ^２は、それぞれ独立に、シクロヘキサン環又はベンゼン環であり、これらは置換基を有していてもよい。Ｒ^１は、水素原子又は炭素数１〜２０のアルキル基である。Ｘは、酸素原子、＋−ＣＯ−Ｏ−、＋−Ｏ−ＣＯ−、＋−Ｏ−ＣＨ_２−、＋−ＣＨ_２−Ｏ−、＋−ＣＯ−Ｓ−、＋−Ｓ−ＣＯ−、＋−ＣＯＮＨ−又は＋−ＮＨＣＯ−（但し、「＋」はフェニレン基との結合手を示す。）である。ｎ^１は１又は２であり、ｎ^２は０又は１である。但し、ｎ^１が２の場合、複数のＡｃ^１はそれぞれ独立して上記定義を有する。ｍは１〜３の整数である。「＊」は結合手を示す。） In one aspect, the present invention is a liquid crystal aligning agent comprising at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, polyimide and polyorganosiloxane, wherein the polymer is represented by the following formula (0 The liquid crystal aligning agent containing the polymer (P1) which has group represented by this is provided.

(In the formula (0), Ac ¹ and Ac ² are independently a cyclohexane ring or a benzene ring, which may have a substituent .R ¹ is a hydrogen atom or a C1-20 a is .X is an alkyl group, an oxygen atom, + - CO-O -, + - O-CO -, + - O-CH 2 -, + - CH 2 -O -, + - CO-S -, + -S-CO-, + -CONH- or + -NHCO- (where "+" represents a bond to a phenylene group) n ¹ is 1 or 2 and n ² is 0 or 1 (However, when n ¹ is 2, a plurality of Ac ¹ have the above definition independently. M is an integer of ¹ to 3. “*” represents a bond.)

  According to the liquid crystal aligning agent of this invention, the liquid crystal aligning film which can express the outstanding liquid crystal aligning property can be formed by containing the said polymer (P1) at least in part as a polymer component. Moreover, according to the liquid crystal aligning agent of this invention, the liquid crystal aligning film which can be peeled easily from a board | substrate and has favorable light resistance can be formed.

（式（１）中、Ａｃ^１、Ａｃ^２、Ｒ^１、Ｘ、ｎ^１、ｎ^２、ｎ^１及びｍは、上記式（０）と同義である。） In the liquid crystal aligning agent of the present invention, the polymer (P1) includes at least one compound selected from the group consisting of a tetracarboxylic dianhydride and a tetracarboxylic acid diester compound, and a compound represented by the following formula (1): It is preferable that it is at least 1 type selected from the group which consists of a polyamic acid obtained by making it react with the diamine containing this, a polyamic acid ester, and a polyimide. By reacting a diamine having a group represented by the above formula (0) with tetracarboxylic dianhydride, a polymer having a group represented by the above formula (0) in the side chain can be relatively easily obtained. Can be synthesized.

(In the formula ^{(1), Ac 1, Ac} 2, R 1, X, n 1, n 2, n 1 and m are as defined above formulas (0).)

In the liquid crystal aligning agent of the present invention, as the polymer (P1), the sum of n ¹ and n ² is preferably 2 or 3, and the sum of n ¹ and n ² is 2. It is more preferable. X is preferably an oxygen atom, + -COO- or + -O-CO- (where "+" represents a bond with a phenylene group). In this case, the voltage holding ratio of the liquid crystal display element can be further increased.

  In one aspect, the present invention provides a liquid crystal alignment film formed using the liquid crystal aligning agent described above. Furthermore, this invention provides the liquid crystal display element which comprises the said liquid crystal aligning film in another one side surface.

  In another aspect of the present invention, at least one compound selected from the group consisting of a tetracarboxylic dianhydride and a tetracarboxylic diester compound, and a diamine containing a compound represented by the above formula (1) A polymer obtained by reaction is provided. Moreover, the compound represented by the said Formula (1) is provided.

（式（０）中、Ａｃ^１、Ａｃ^２、Ｒ^１、Ｘ、ｎ^１、ｎ^２、ｎ^１、ｍ及び「＊」は、上記と同義である。） Below, the liquid crystal aligning agent of this invention is demonstrated in detail.
<Liquid crystal aligning agent>
The liquid crystal aligning agent of this invention contains at least 1 type of polymer selected from the group which consists of a polyamic acid, polyamic acid ester, a polyimide, and polyorganosiloxane as a polymer component. In particular, the polymer includes a polymer (P1) having a group represented by the following formula (0).

(In the formula (0), Ac ¹ , Ac ² , R ¹ , X, n ¹ , n ² , n ¹ , m and “*” are as defined above.)

In the above formula (0), the alkyl group having 1 to 20 carbon atoms in R ¹ may be linear or branched. Specifically, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n-heptyl group, n-octyl group, n-nonyl Group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group Group, n-icosyl group and the like.
Among them, R ¹ is preferably a linear alkyl group having 3 to 12 carbon atoms, and more preferably a linear alkyl group having 3 to 7 carbon atoms.
X is preferably an oxygen atom, + -CO-O- or + -O-CO-, and particularly preferably an oxygen atom in that the voltage holding ratio of the liquid crystal display element can be increased.

Ac ¹ and Ac ² may be both a cyclohexane ring, a benzene ring, or a combination of a cyclohexane ring and a benzene ring. Especially, it is preferable that both Ac ¹ and Ac ² are cyclohexane rings from the viewpoints of liquid crystal orientation and solubility in a solvent. When Ac ¹ and Ac ² are cyclohexane rings, the cis-trans isomerism of the 1,4-cyclohexylene group is preferably a trans isomer.
Each of Ac ¹ and Ac ² may have a substituent. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, alkyl group having 1 to 5 carbon atoms, fluoroalkyl group or alkoxy group, hydroxyl group, cyano group and nitro group. It is done.
The combination of n ¹ and n ² is not particularly limited as long as n ¹ is 1 or 2 and n ² is 0 or 1. Among them, the sum (n ¹ + n ² ) of n ¹ and n ² is preferably 2 or 3, and (n ¹ + n ² ) is more preferably 2. That is, the combination of n ¹ and n ² is preferably n ¹ = 1 and n ² = 2, n ¹ = 1 and n ² = 1, or n ¹ = 2 and n ² = 0, and n ¹ More preferably, = 1 and n ² = 1, or n ¹ = 2 and n ² = 0.

The group represented by the above formula (0) has an alkylene group having 2, 4, or 6 carbon atoms between the ring Ac ¹ and the ring Ac ² . In the side chain of the polymer, by having the alkylene group between ring Ac ¹ and ring Ac ² (between ring Ac ¹ and the benzene ring when n ² = 0), the liquid crystal of the liquid crystal alignment film This is preferable in that the molecular orientation can be further enhanced. The alkylene group preferably has 2 or 4 carbon atoms, and particularly preferably has 2 carbon atoms.

（式中、Ｒ^１及び「＊」は、上記式（０）と同義である。） Specific examples of the group represented by the above formula (0) include groups represented by the following formulas (0-1) to (0-10), and among these, the following formulas A group represented by each of (0-1) to (0-6) is preferable.

(In the formula, R ¹ and “*” have the same meanings as in the above formula (0).)

<Polymer (P1): Polyamic acid>
One example of the polymer (P1) in the present invention is a polyamic acid having a group represented by the above formula (0). The polyamic acid is, for example, [I] a method of reacting a tetracarboxylic dianhydride having a group represented by the above formula (0) with a diamine; [II] a tetracarboxylic dianhydride and the above formula. It can be obtained by a method of reacting a diamine having a group represented by (0). Of these, the method [II] is preferably used because it is easy to produce. Hereinafter, the case where the polyamic acid having a group represented by the above formula (0) is synthesized using the method [II] will be described as an example.

[Tetracarboxylic dianhydride]
Examples of the tetracarboxylic dianhydride used for synthesizing the polyamic acid in the present invention include an aliphatic tetracarboxylic dianhydride, an alicyclic tetracarboxylic dianhydride, an aromatic tetracarboxylic dianhydride, and the like. Can be mentioned. Specific examples of these are:
Examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride;
Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a, 4, 5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b- Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3.2.1] octane -2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene- No 1,2-dicarboxylic acid 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2 : 4,6: 8-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, cyclohexanetetracarboxylic dianhydride Etc .;
Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride;
In addition to the above, tetracarboxylic dianhydrides described in JP 2010-97188 A can be used. In addition, the said tetracarboxylic dianhydride can be used individually by 1 type or in combination of 2 or more types.

The tetracarboxylic dianhydride used for synthesizing the polyamic acid preferably contains an alicyclic tetracarboxylic dianhydride in terms of good solubility in a solvent and transparency. Among them, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1, 2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1, 2-c] furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride and 1,2,3 More preferably, it contains at least one selected from the group consisting of 4-cyclobutanetetracarboxylic dianhydride (hereinafter also referred to as “specific tetracarboxylic dianhydride”), and 2,3,5-tricarboxycyclopentyl. Acetic dianhydride Group consisting of 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride More preferably, at least one selected from the group consisting of:
As tetracarboxylic dianhydride used for the synthesis of polyamic acid, the above-mentioned specific tetracarboxylic dianhydride is contained in an amount of 20 mol% or more based on the total amount of tetracarboxylic dianhydride used for synthesis. It is preferable that 50 mol% or more is included, and 80 mol% or more is more preferable.

（式（１）中、Ａｃ^１、Ａｃ^２、Ｒ^１、Ｘ、ｎ^１、ｎ^２及びｍは、上記式（０）と同義である。） [Diamine]
・ Specific diamine (D)
The diamine used for the synthesis of the polyamic acid in the present invention contains a diamine having a group represented by the above formula (0) (hereinafter also referred to as a specific diamine (D)). The specific diamine (D) may be any of aliphatic diamine, alicyclic diamine, aromatic diamine, diaminoorganosiloxane and the like. Among the specific diamines (D), aromatic diamines are preferable, and specific examples include compounds represented by the following formula (1).

(In the formula ^{(1), Ac 1, Ac} 2, R 1, X, n 1, n 2 and m is as defined in the above formula (0).)

In the formula (1), the explanation of the above formula (0) can be applied as it is to preferred specific examples of Ac ¹ , Ac ² , R ¹ , X, n ¹ , n ² and m.
The two primary amino groups in the diaminophenyl group are preferably in the 2,4-position or 3,5-position with respect to X. Which of these bonding positions is more preferable depends on the type of X bonded to the diaminophenyl group. For example, when X is an oxygen atom, the 2,4-position or 3,5- It is preferably in the position, and when X is “+ -O—CO—” or “+ —CO—O—”, it is preferably in the 3,5-position with respect to X.

（式中、Ｒ^１は上記式（０）と同義である。）
上記特定ジアミン（Ｄ）としては、これらの中でも、下記式（１−１）〜（１−６）のそれぞれで表される化合物が好ましく、下記式（１−１）〜（１−４）のそれぞれで表される化合物がより好ましい。 Specific examples of the specific diamine (D) include compounds represented by the following formulas (1-1) to (1-10), for example.

(In the formula, R ¹ has the same meaning as the above formula (0).)
Among these, as the specific diamine (D), compounds represented by the following formulas (1-1) to (1-6) are preferable, and the following formulas (1-1) to (1-4) are preferable. The compound represented by each is more preferable.

-Synthesis | combination of specific diamine Said specific diamine (D) can be synthesize | combined by combining the normal method of organic chemistry suitably. As an example, for example, dinitrobenzene having a group represented by the above formula (0) is synthesized, and then the nitro group of the obtained dinitro compound is hydrogenated using an appropriate reduction system to form an amino group. Can be synthesized.
Here, for example, when “X” is an oxygen atom, the dinitro compound includes a corresponding alkylcyclohexylphenol and a dinitro group-containing halide such as dinitrochlorobenzene and dinitrofluorobenzene. It can be synthesized by reacting in the presence of an alkali such as sodium hydrogen carbonate, potassium carbonate, or lithium carbonate. Alternatively, it can be synthesized by reacting a corresponding halide having an alkylcyclohexyl structure with a hydroxyl group derivative containing a dinitro group such as dinitrophenol in the presence of an alkali.
When “X” is “+ -O—CH ₂ —”, a corresponding alkylcyclohexylphenol is reacted with a dinitro group-containing halide such as dinitrobenzyl chloride in the presence of an alkali. Can be synthesized.
When “X” is “+ —CH ₂ —O—”, a corresponding halide having an alkylcyclohexyl structure is reacted with a hydroxyl group derivative containing a dinitro group such as dinitrophenol in the presence of an alkali. Can be synthesized.
When "X" is "+ -O-CO-", the corresponding alkylcyclohexylphenols and dinitro group-containing carboxylic acid halides such as dinitrobenzoyl chloride and dinitrobromide benzoyl, for example, It can be synthesized by reacting in the presence of a suitable base such as triethylamine.
When "X" is "+ -CO-O-", the presence of a suitable base between a corresponding carboxylic acid halide having an alkylcyclohexyl structure and a dinitro group-containing hydroxyl group derivative such as dinitrophenol It can synthesize | combine by making it react under.
When "X" is "+ -S-CO-", a corresponding thiol compound having an alkylcyclohexyl structure and a dinitro group-containing carboxylic acid halide such as dinitrobenzoyl chloride, such as triethylamine It can synthesize | combine by making it react in presence of a suitable base.
When "X" is "+ -CO-S-", a carboxylic acid halide having a corresponding alkylcyclohexyl structure and a thiol derivative containing a dinitro group such as dinitrothiophenol are mixed with an appropriate base. It can be synthesized by reacting in the presence.
When "X" is "+ -NHCO-", an amino group-substituted product having a corresponding alkylcyclohexyl structure and a dinitro group-containing carboxylic acid halide such as dinitrobenzoyl chloride are mixed with an appropriate base. It can be synthesized by reacting in the presence.
When "X" is "+ -CONH-", the presence of a suitable base between the corresponding carboxylic acid halide having an alkylcyclohexyl structure and a dinitro group-containing amino group-substituted product such as dinitroaniline It can synthesize | combine by making it react under.

  The reaction for obtaining the dinitro compound is preferably carried out in an organic solvent. The reaction temperature at this time is preferably −20 ° C. to 180 ° C., more preferably 0 to 120 ° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours. As the organic solvent, compounds usually used in the substitution reaction can be used. Specific examples include alcohol, tetrahydrofuran, toluene, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1-methyl-2-pyrrolidone and the like. be able to.

  The reduction reaction of the dinitro compound can be carried out in an organic solvent using, for example, zinc, lithium aluminum hydroxide, palladium catalyst-hydrogen system or the like. As the organic solvent, compounds usually used in the reduction reaction can be used, and specific examples include tetrahydrofuran, alcohol and the like. The reaction temperature is preferably -20 ° C to 180 ° C, more preferably 10 to 120 ° C. The reaction time is preferably 0.1 to 72 hours, more preferably 0.5 to 48 hours. However, the synthesis method of specific diamine (D) is not limited to the said method.

-Other diamines As a diamine used in order to synthesize the polyamic acid in this invention, only the said specific diamine (D) may be used, and another diamine may be used together with a specific diamine (D). .

Examples of other diamines that can be used here include aliphatic diamines, alicyclic diamines, aromatic diamines, and diaminoorganosiloxanes. Specific examples of these include aliphatic diamines such as metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, and the like;
Examples of alicyclic diamines include 1,4-diaminocyclohexane, 4,4′-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane and the like;

（式中、Ｘ^I及びＸ^IIは、それぞれ、単結合、−Ｏ−、−ＣＯＯ−又は−ＯＣＯ−であり、Ｒ^Ｉは、炭素数１〜３のアルカンジイル基であり、ａは０又は１であり、ｂは０〜２の整数であり、ｃは１〜２０の整数であり、ｎは０又は１である。但し、ａ及びｂが同時に０になることはない。）
で表される化合物などを； Examples of aromatic diamines include p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl ] Propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane 4,4 ′-(p-phenylenediisopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylene Riden) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diamino Pyrimidine, 3,6-diaminoacridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N , N′-bis (4-aminophenyl) -benzidine, N, N′-bis (4-aminophenyl) -N, N′-dimethylbenzidine, 1,4-bis- (4-aminophenyl) -piperazine, 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-indene-5-amine, 1- (4-aminophen 2) -2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine, 3,5-diaminobenzoic acid, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3, 5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestenyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate, 3,5-diamino Lanostanyl benzoate, 3,6-bis (4-aminobenzoyloxy) cholestane, 3,6-bis (4-aminophenoxy) cholestane, 4- (4′-trifluoromethoxybenzoyloxy) cyclohexyl-3,5- Diaminobenzoate, 4- (4′-trifluoromethylbenzoyloxy) cyclohexyl-3,5-di Aminobenzoate, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-butylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-heptylcyclohexane, , 1-bis (4-((aminophenoxy) methyl) phenyl) -4-heptylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4- (4-heptylcyclohexyl) cyclohexane, 2,4-diamino-N, N-diallylaniline, 4-aminobenzylamine, 3-aminobenzylamine, and the following formula (A-1)

Wherein X ^I and X ^II are each a single bond, —O—, —COO— or —OCO—, R ^I is an alkanediyl group having 1 to 3 carbon atoms, and a is 0 or And b is an integer of 0 to 2, c is an integer of 1 to 20, and n is 0 or 1. However, a and b are not 0 at the same time.)
A compound represented by:

Examples of diaminoorganosiloxane include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane;
In addition to these, diamines described in JP 2010-97188 A can be used. As other diamine, these can be used individually by 1 type or in combination of 2 or more types.

Examples of the divalent group represented by “—X ^I — (R ^I —X ^II ) _n —” in the formula (A-1) include alkanediyl groups having 1 to 3 carbon atoms, * —O—, * —COO— or * —O—C ₂ H ₄ —O— (however, a bond marked with “*” is bonded to a diaminophenyl group) is preferred. Specific examples of the group “—C _c H _{2c + 1} ” include the groups exemplified as the alkyl group having 1 to 20 carbon atoms in R ¹ of the above formula (0). The two amino groups in the diaminophenyl group are preferably in the 2,4-position or 3,5-position with respect to other groups.

Specific examples of the compound represented by the formula (A-1) include compounds represented by the following formulas (A-1-1) to (A-1-3).

  The content ratio of the specific diamine (D) is preferably 1 mol% or more, and more preferably 1 to 50 mol%, based on the total amount of diamine used for the synthesis of the polyamic acid. By setting the content ratio to 1 mol% or more, the pretilt angle of the liquid crystal alignment film formed using the liquid crystal aligning agent can be further increased. The content ratio is particularly preferably 5 to 30 mol%.

[Molecular weight regulator]
When synthesizing a polyamic acid, a terminal-modified polymer may be synthesized using an appropriate molecular weight regulator together with the tetracarboxylic dianhydride and diamine as described above. By using such a terminal-modified polymer, the coating property (printability) of the liquid crystal aligning agent can be further improved without impairing the effects of the present invention.

Examples of molecular weight regulators include acid monoanhydrides, monoamine compounds, monoisocyanate compounds, and the like. Specific examples of these acid monoanhydrides include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic acid. Nic acid anhydride, n-hexadecyl succinic acid anhydride, etc .;
Examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; examples of monoisocyanate compounds include phenyl isocyanate and naphthyl isocyanate; Each can be mentioned.

  The use ratio of the molecular weight regulator is preferably 20 parts by weight or less, and more preferably 10 parts by weight or less with respect to 100 parts by weight of the total of the tetracarboxylic dianhydride and diamine used.

<Synthesis of polyamic acid>
The ratio of the tetracarboxylic dianhydride and the diamine used in the polyamic acid synthesis reaction in the present invention is such that the acid anhydride group of the tetracarboxylic dianhydride is 0. A ratio of 2 to 2 equivalents is preferable, and a ratio of 0.3 to 1.2 equivalents is more preferable.
The polyamic acid synthesis reaction is preferably carried out in an organic solvent. The reaction temperature at this time is preferably −20 ° C. to 150 ° C., more preferably 0 to 100 ° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

Examples of the organic solvent include aprotic polar solvents, phenol solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons.
Specific examples of these organic solvents include, for example, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, N, N as the aprotic polar solvent. -Dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide and the like; as the phenolic solvent, for example, phenol, m-cresol, xylenol, halogenated phenol, etc. ;
Examples of the alcohol include methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, and the like. Examples of the ketone include acetone, Examples of the ester include, for example, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, and malon Diethyl acid, isoamyl propionate, isoamyl isobutyrate and the like;
Examples of the ether include diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether. Acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, diisopentyl ether and the like;
Examples of the halogenated hydrocarbon include dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, and the like. Examples of the hydrocarbon include hexane, heptane, octane, Benzene, toluene, xylene, etc. can be mentioned respectively.

Among these organic solvents, one or more selected from the group consisting of an aprotic polar solvent and phenol and derivatives thereof (first group organic solvent), or one or more selected from the first group of organic solvents And a mixture of at least one selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (second group organic solvent). In the latter case, the proportion of the second group organic solvent used is preferably 50% by weight or less, more preferably 40% by weight, based on the total amount of the first group organic solvent and the second group organic solvent. Or less, more preferably 30% by weight or less.
The amount of organic solvent used (a) is such that the total amount (b) of tetracarboxylic dianhydride and diamine is 0.1 to 50% by weight based on the total amount (a + b) of the reaction solution. It is preferable.

  As described above, a reaction solution obtained by dissolving polyamic acid is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid contained in the reaction solution, or the isolated polyamic acid was purified. You may use for preparation of a liquid crystal aligning agent. When polyamic acid is dehydrated and cyclized into a polyimide, the above reaction solution may be directly subjected to dehydration and cyclization reaction, or may be subjected to dehydration and cyclization reaction after isolating the polyamic acid contained in the reaction solution. Alternatively, the isolated polyamic acid may be purified and then subjected to a dehydration ring closure reaction. Isolation and purification of the polyamic acid can be performed according to known methods.

<Polymer (P1): Polyamic acid ester>
As a polymer (P1) contained in the liquid crystal aligning agent of this invention, the polyamic acid ester which has group represented by the said Formula (0) is mentioned. The polyamic acid ester is, for example, [I] a method of synthesizing a polyamic acid obtained by the above synthesis reaction by esterification using a hydroxyl group-containing compound or an ether compound, [II] a tetracarboxylic acid diester compound, It can obtain by the method of making the diamine compound containing the said specific diamine (D) react. Here, the tetracarboxylic acid diester compound in the method [II] includes a tetracarboxylic acid diester compound which is a precursor of the tetracarboxylic dianhydride, specifically, for example, tetracarboxylic acid diester dichloride, Examples thereof include tetracarboxylic acid diester having two carboxyl groups. Moreover, as said diamine used in method [II], you may use said other diamine with said specific diamine (D). The polyamic acid ester as the polymer (P1) may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist.

<Polymer (P1): Polyimide>
Another form of the polymer (P1) contained in the liquid crystal aligning agent of the present invention is a polyimide having a group represented by the above formula (0). The polyimide can be obtained by dehydrating and ring-closing and imidizing the polyamic acid having the group represented by the above formula (0) synthesized as described above.

  The polyimide may be a completely imidized product obtained by dehydrating and cyclizing all of the amic acid structure possessed by the polyamic acid that is the precursor, and only a part of the amic acid structure is dehydrated and cyclized, It may be a partially imidized product in which an imide ring structure coexists. The polyimide in the present invention preferably has an imidation ratio of 30% or more, more preferably 50 to 99%, and still more preferably 60 to 99%. This imidation ratio represents the ratio of the number of imide ring structures to the total of the number of polyimide amic acid structures and the number of imide ring structures in percentage. Here, a part of the imide ring may be an isoimide ring.

  The polyamic acid is preferably dehydrated and closed by heating the polyamic acid, or by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to the solution, and heating the solution as necessary. . Of these, the latter method is preferred.

  In the method of adding a dehydrating agent and a dehydrating ring-closing catalyst to the polyamic acid solution, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride can be used as the dehydrating agent. It is preferable that the usage-amount of a dehydrating agent shall be 0.01-20 mol with respect to 1 mol of the amic acid structure of a polyamic acid. As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, triethylamine and the like can be used. It is preferable that the usage-amount of a dehydration ring-closing catalyst shall be 0.01-10 mol with respect to 1 mol of dehydrating agents to be used. Examples of the organic solvent used in the dehydration ring-closing reaction include the organic solvents exemplified as those used for the synthesis of polyamic acid. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C, more preferably 10 to 150 ° C. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

  In this way, a reaction solution containing polyimide is obtained. This reaction solution may be used for the preparation of the liquid crystal aligning agent as it is, may be used for the preparation of the liquid crystal aligning agent after removing the dehydrating agent and the dehydrating ring-closing catalyst from the reaction solution, and the liquid crystal after isolating the polyimide. You may use for preparation of an aligning agent, or you may use for preparation of a liquid crystal aligning agent, after purifying the isolated polyimide. These purification operations can be performed according to known methods.

The polyamic acid, polyamic acid ester and polyimide obtained as described above preferably have a solution viscosity of 10 to 800 mPa · s, when this is made into a solution having a concentration of 10% by weight, and 15 to 500 mPa · s. More preferably, it has a solution viscosity of s. In addition, the solution viscosity (mPa · s) of the above polymer is based on a polymer solution having a concentration of 10% by weight prepared using a good solvent for the polymer (eg, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). The value measured at 25 ° C. using an E-type rotational viscometer.
Regarding the polyamic acid, polyamic acid ester, and polyimide, the polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography is preferably 1,000 to 500,000, and preferably 2,000 to 300,000. More preferred.

<Polymer (P1): Polyorganosiloxane>
Another form of the polymer (P1) contained in the liquid crystal aligning agent of the present invention is a polyorganosiloxane having a group represented by the above formula (0). The polyorganosiloxane is, for example, a polymer obtained by hydrolytic condensation of (I) a hydrolyzable silane compound (s1) having an epoxy group, or a mixture of the silane compound (s1) and another silane compound. And a carboxylic acid having a group represented by the above formula (0); (II) a hydrolyzable silane compound (s2) having a group represented by the above formula (0), or A method of hydrolyzing and condensing a mixture of the silane compound (s2) and another silane compound; In the above methods (I) and (II), organic chemistry methods may be combined appropriately.

  For the polyorganosiloxane, the polystyrene-reduced weight average molecular weight measured by gel permeation chromatography is preferably 500 to 1,000,000, more preferably 1,000 to 100,000, More preferably, it is 000-50,000.

The liquid crystal aligning agent of this invention is a polymer selected from the group which consists of said polyamic acid, polyamic acid ester, a polyimide, and polyorganosiloxane as a polymer (P1) individually by 1 type or in combination of 2 or more types. Contained. In the liquid crystal aligning agent of the present invention, the content ratio of each polymer with respect to the total amount of the polymer (P1) can be appropriately selected depending on the use and environment to be used, but from the viewpoint of more suitably obtaining the effects of the present invention. Then, the polymer (P1) preferably contains at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, and the polymer (P1) is at least one selected from the group consisting of polyamic acid and polyimide. It is more preferable that the polymer (P1) is at least one selected from the group consisting of polyamic acid and polyimide.
When the polymer (P1) contains at least one of polyamic acid and polyimide, the total content is 1 to 100% by weight with respect to the total amount of the polymer (P1) contained in the liquid crystal aligning agent. It is preferable that it is 5 to 100% by weight. In addition, as a polymer (P1), 1 type of the polymer shown above may be used independently, and 2 or more types may be used in combination. When two or more types are used in combination, a combination of polymers having the same main skeleton may be used, or a combination of polymers having different main skeletons may be used.

<Solvent>
The liquid crystal aligning agent of the present invention is preferably constituted by dissolving the above polymer in an organic solvent.
The solvent used for the preparation of the liquid crystal aligning agent of the present invention varies depending on the type of polymer contained in the liquid crystal aligning agent. Specifically, the liquid crystal aligning agent of the present invention is a polymer, and at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester and polyimide alone or a polymer such as the polyamic acid When it contains polyorganosiloxane, for example, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone , Ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propiate Ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol Mention may be made of propylene glycol monomethyl ether (DPM), diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate and the like. These can be used alone or in admixture of two or more.
On the other hand, when the liquid crystal aligning agent of the present invention contains only polyorganosiloxane as a polymer, for example, alcohol such as 1-ethoxy-2-propanol, propylene glycol monoethyl ether, butyl cellosolve; ether such as diethylene glycol ethyl methyl ether; Examples include esters such as -propyl, i-propyl acetate, n-butyl acetate, i-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, and isoamyl acetate.

<Other ingredients>
The liquid crystal aligning agent of this invention may contain the other component as needed. Examples of such other components include other polymers other than the specific polymer, compounds having at least one epoxy group in the molecule (hereinafter referred to as “epoxy group-containing compound”), functional silane compounds, and the like. be able to.

[Other polymers]
The above other polymers can be used for improving solution properties and electrical properties. Examples of such other polymers include polymers having no group represented by the above formula (0) among polyamic acid, polyamic acid ester, polyimide and polyorganosiloxane, polyester, polyamide, cellulose derivative, polyacetal, polystyrene. Derivatives, poly (styrene-phenylmaleimide) derivatives, poly (meth) acrylates and the like can be mentioned. When other polymers are added to the liquid crystal aligning agent, the blending ratio is preferably 50% by weight or less, more preferably 0.1 to 40% by weight, more preferably 0.1% by weight to the total amount of the polymer in the composition. 1 to 30% by weight is more preferable.

[Epoxy group-containing compound]
The epoxy group-containing compound can be used to improve the adhesion and electrical properties with the substrate surface in the liquid crystal alignment film. Here, 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, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, N, N, N ′, N′-tetraglycidyl-m-xylenediamine 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodi Enirumetan, N, N-diglycidyl - benzylamine, N, N-diglycidyl - aminomethyl cyclohexane, N, N-diglycidyl - may be mentioned as being preferred and cyclohexylamine.
In addition, as an example of the epoxy group-containing compound, an epoxy group-containing polyorganosiloxane described in International Publication No. 2009/096598 can also be used.
When these epoxy compounds are added to the liquid crystal aligning agent, the blending ratio is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the total of the polymers contained in the liquid crystal aligning agent. preferable.

[Functional silane compounds]
The functional silane compound can be used for the purpose of improving the printability of the liquid crystal aligning agent. Examples of such functional silane compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl). ) -3-Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3- Aminopropyltrimethoxysilane, N-triethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-trimethoxysilyl -3,6- Methyl azananoate, N-benzyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, glycidoxymethyltrimethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-glycid And xylpropyltrimethoxysilane.
When these functional silane compounds are added to the liquid crystal aligning agent, the blending ratio is preferably 2 parts by weight or less, more preferably 0.02 to 0.2 parts by weight, based on 100 parts by weight of the total polymer.

  As other components, in addition to the above, a compound having at least one oxetanyl group in the molecule, an antioxidant, or the like can be used.

  The solid content concentration in the liquid crystal aligning agent of the present invention (the ratio of the total weight of components other than the solvent of the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, and the like. The range is preferably 1 to 10% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface as described later, and preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that becomes a liquid crystal alignment film. When the solid content concentration is less than 1% by weight, the film thickness of the coating film is too small to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes excessive and a good liquid crystal alignment film cannot be obtained, and the viscosity of the liquid crystal aligning agent increases and the coating characteristics are increased. Is inferior.

The particularly preferable solid content concentration range varies depending on the method used when applying the liquid crystal aligning agent to the substrate. For example, when the spinner method is used, the solid content concentration is particularly preferably in the range of 1.5 to 4.5% by weight. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the inkjet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s.
The temperature at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 10-50 degreeC, More preferably, it is 20-30 degreeC.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal alignment film of the present invention is formed by the liquid crystal aligning agent prepared as described above. Moreover, the liquid crystal display element of this invention comprises the liquid crystal aligning film formed using the said liquid crystal aligning agent. The operation mode of the liquid crystal display element is not particularly limited, but a vertical alignment type such as a VA type or an MVA type is particularly preferable.

  Below, while explaining the manufacturing method of the liquid crystal display element of this invention, the manufacturing method of the liquid crystal aligning film of this invention is also demonstrated in the description. Hereinafter, a method for manufacturing a VA liquid crystal display element will be described as an example.

[Step (1): Formation of coating film]
First, the liquid crystal aligning agent of this invention is apply | coated on a board | substrate, Then, a coating film is formed on a board | substrate by heating an application surface.
First, as a pair of two substrates provided with a patterned transparent conductive film, the liquid crystal aligning agent of the present invention is preferably formed on the surface of the transparent conductive film on the substrate, preferably by an offset printing method or a spin coating method. They are respectively applied by a roll coater method or an ink jet printing method. Here, as the substrate, for example, a glass such as float glass or soda glass; a transparent substrate made of a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or poly (alicyclic olefin) can be used. As a transparent conductive film provided on one surface of the substrate, an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), etc. Can be used. In order to obtain a patterned transparent conductive film, for example, after forming a transparent conductive film without a pattern, a method of forming a pattern by photo-etching, a method of using a mask having a desired pattern when forming the transparent conductive film, etc. Can be. When applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate surface and the transparent conductive film and the coating film, a functional silane compound or functional titanium is formed on the surface of the substrate surface on which the coating film is to be formed. You may give the pretreatment which apply | coats a compound etc. previously.

  After applying the liquid crystal aligning agent, preheating (pre-baking) is preferably performed for the purpose of preventing dripping of the applied liquid crystal aligning agent. The pre-baking temperature is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 40 to 100 ° C. The pre-bake time is preferably 0.25 to 10 minutes, and more preferably 0.5 to 5 minutes. Then, a baking (post-baking) process is implemented for the purpose of removing a solvent completely and heat imidating the amic acid structure which exists in a polymer as needed. The post-bake temperature is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The post-bake time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. Thus, the film thickness of the formed film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.

  By removing the organic solvent by heating after applying the liquid crystal aligning agent, a coating film to be an alignment film is formed. At this time, when the polymer contained in the liquid crystal aligning agent of the present invention is a polyamic acid, a polyamic acid ester, or an imidized polymer having an imide ring structure and an amic acid structure, It is good also as a more imidized coating film by advancing the dehydration ring-closing reaction by further heating after the coating film formation.

[Step (2): Construction of liquid crystal cell]
Two substrates on which the liquid crystal alignment film is formed as described above are prepared, and a liquid crystal cell is manufactured by disposing a liquid crystal between the two substrates disposed to face each other.

In order to manufacture a liquid crystal cell, the following two methods are mentioned, for example.
The first method is a conventionally known method (vacuum injection method). First, two substrates are arranged opposite to each other through a gap (cell gap) so that the respective liquid crystal alignment films are opposed to each other, and the peripheral portions of the two substrates are bonded together using a sealant, and the substrate surface and the sealant are bonded. A liquid crystal cell is manufactured by injecting and filling liquid crystal into the cell gap partitioned by the step, and then sealing the injection hole. The second method is a method called an ODF (One Drop Fill) method. For example, an ultraviolet curable sealing material is applied to a predetermined location on one of the two substrates on which the liquid crystal alignment film is formed, and liquid crystal is dropped to predetermined locations on the surface of the liquid crystal alignment film. Thereafter, the other substrate is bonded so that the liquid crystal alignment film faces, and the liquid crystal is spread over the entire surface of the substrate, and then the entire surface of the substrate is irradiated with ultraviolet light to cure the sealant, thereby manufacturing a liquid crystal cell. . Regardless of which method is used, the liquid crystal cell produced as described above is further heated to a temperature at which the liquid crystal used takes an isotropic phase and then gradually cooled to room temperature. It is desirable to remove. And the liquid crystal display element of this invention can be obtained by bonding a polarizing plate on the outer surface of a liquid crystal cell.

As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.
Examples of the liquid crystal include nematic liquid crystal and smectic liquid crystal. Among them, nematic liquid crystal is preferable. For example, Schiff base liquid crystal, azoxy liquid crystal, biphenyl liquid crystal, phenylcyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl. Cyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, cubane liquid crystals, and the like can be used. Further, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, and cholesteryl carbonate; chiral agents such as those sold under the trade names “C-15” and “CB-15” (manufactured by Merck & Co., Inc.). A ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate may be added and used.
As a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film itself in which a polarizing film called an “H film” in which iodine is absorbed while stretching and aligning polyvinyl alcohol is sandwiched between cellulose acetate protective films The polarizing plate which consists of can be mentioned.

  The liquid crystal display element of the present invention can be effectively applied to various devices, such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, It can be used for various display devices such as various monitors, liquid crystal televisions, and information displays.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

The solution viscosity of each polymer solution and the imidation ratio of polyimide in the synthesis examples were measured by the following methods.
[Solution viscosity of polymer solution]
The solution viscosity [mPa · s] of the polymer solution was measured at 25 ° C. using an E-type rotational viscometer for a solution prepared to a polymer concentration of 10% by weight using a predetermined solvent.
[Imidation rate of polyimide]
The polyimide solution was poured into pure water, and the resulting precipitate was sufficiently dried under reduced pressure at room temperature, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance. From the obtained ¹ H-NMR spectrum, the imidization rate [%] was determined by the formula shown by the following formula (1a).
Imidation ratio [%] = (1-A ¹ / A ² × α) × 100 (1a)
(In Formula (1a), A ¹ is a peak area derived from protons of NH groups appearing near a chemical shift of 10 ppm, A ² is a peak area derived from other protons, and α is a polymer precursor (polyamic acid). The number ratio of other protons to one proton of NH group in)

<Synthesis of specific diamine (D)>
[Synthesis Example 1: Synthesis of Compound (D-1)]
Compound (D-1) was synthesized according to the following scheme 1.

  In a 500 mL three-necked flask equipped with a thermometer and a nitrogen inlet tube, a compound represented by the above formula (1-1-1A) (provided that the cis-trans isomerism of 1,4-cyclohexylene group is the trans isomer, respectively. 35.7 g, 2,4-dinitrochlorobenzene 20.3 g, potassium carbonate 15.2 g and N, N-dimethylacetamide 300 mL were added and reacted at 100 ° C. for 4 hours. After completion of the reaction, 1 L of ethyl acetate and 1 L of tetrahydrofuran 500 mL 1M hydrochloric acid were added to remove the aqueous layer, followed by washing with water three times. Next, after adding magnesium sulfate to the organic layer and drying, the crystals precipitated by concentration are collected and dried to obtain 36 pale yellow crystals of the compound represented by the above formula (1-1-1B). 0.6 g was obtained.

  Subsequently, in a 1 L three-necked flask equipped with a thermometer and a nitrogen introduction tube, 36.6 g of the compound represented by the above formula (1-1-1B), 1.83 g of palladium carbon, 350 mL of tetrahydrofuran, 350 mL of ethanol, and 80%. 39.4 g of an aqueous hydrazine monohydrate solution was added and reacted at room temperature for 20 hours. After completion of the reaction, 1 L of ethyl acetate was added and washed with water three times. Then, the organic layer was concentrated and the precipitated crystals were filtered and dried, whereby the compound represented by the above formula (1-1-1) ( 25.9 g of pale brown crystals of D-1) were obtained.

[Synthesis Example 2: Synthesis of Compound (D-2)]
Compound (D-2) was synthesized according to the following scheme 2.

  In a 500 mL three-necked flask equipped with a dropping funnel, a thermometer and a nitrogen introduction tube, the compound represented by the above formula (1-1-1A) (provided that the cis-trans isomerism of the 1,4-cyclohexylene group is 35.7 g of trans isomer), 200 mL of tetrahydrofuran and 11.13 g of triethylamine were added, and the mixture was ice-cooled to 5 ° C. or lower. Next, a solution obtained by dissolving 23.0 g of 3,5-dinitrobenzoyl chloride in 100 mL of tetrahydrofuran was slowly added dropwise over 30 minutes, and the mixture was returned to room temperature and reacted for 1 hour. After completion of the reaction, 500 mL of ethyl acetate and 500 mL of 1M aqueous hydrochloric acid solution were added for liquid separation, and the organic layer was further separated and washed three times with water, and then the organic layer was dried over magnesium sulfate and concentrated to precipitate crystals. By drying, 49.6 g of pale yellow crystals of the compound represented by the above formula (1-2-1B) were obtained.

  Subsequently, after adding 49.6 g of the above formula (1-2-1B), 2.48 g of 5% palladium carbon powder, 300 mL of tetrahydrofuran and 300 mL of ethanol to a 2 L three-necked flask equipped with a thermometer and a nitrogen introduction tube, An aqueous solution of 80% hydrazine monohydrate (51 g) was slowly added, stirred at room temperature for 1 hour, heated to 70 ° C., and further reacted for 2 hours. After completion of the reaction, the filtrate obtained by removing palladium carbon by filtration was concentrated to about 200 mL, 500 mL of ethyl acetate was added, and the mixture was washed three times with water, and then the organic layer was concentrated and the precipitated crystals were filtered. By drying, 39.8 g of white crystals of the compound (D-2) represented by the above formula (1-2-1) was obtained.

[Synthesis Example 3: Synthesis of Compound (D-3)]
Compound (D-3) was synthesized according to the following scheme 3.

  In a 500 mL three-necked flask equipped with a thermometer and a nitrogen inlet tube, a compound represented by the above formula (1-3-1A) (provided that the cis-trans isomerism of the 1,4-cyclohexylene group is the trans isomer, respectively. 35.7 g, 2,4-dinitrochlorobenzene 20.3 g, potassium carbonate 15.2 g and N, N-dimethylacetamide 300 mL were added and reacted at 100 ° C. for 4 hours. After completion of the reaction, 1 L of ethyl acetate and 1 L of tetrahydrofuran 500 mL 1M hydrochloric acid were added to remove the aqueous layer, followed by washing with water three times. Next, magnesium sulfate is added to the organic layer and dried, and then concentrated and precipitated crystals are recovered and dried to obtain 35 pale yellow crystals of the compound represented by the above formula (1-3-1B). .8 g was obtained.

  Subsequently, in a 1 L three-necked flask equipped with a thermometer and a nitrogen introduction tube, 35.8 g of the compound represented by the above formula (1-3-1B), 1.83 g of palladium carbon, 350 mL of tetrahydrofuran, 350 mL of ethanol, and 80%. 39.4 g of an aqueous hydrazine monohydrate solution was added and reacted at room temperature for 20 hours. After completion of the reaction, 1 L of ethyl acetate was added and washed with water three times. Then, the organic layer was concentrated and the precipitated crystals were filtered and dried, whereby the compound represented by the above formula (1-3-1) ( 25.0 g of pale brown crystals of D-3) were obtained.

[Synthesis Example 4: Synthesis of Compound (D-4)]
Compound (D-4) was synthesized according to the following scheme 3.

  In a 500 mL three-necked flask equipped with a dropping funnel, a thermometer and a nitrogen introduction tube, the compound represented by the above formula (1-3-1A) (provided that the cis-trans isomerism of the 1,4-cyclohexylene group is 35.7 g of trans isomer), 200 mL of tetrahydrofuran and 11.13 g of triethylamine were added, and the mixture was ice-cooled to 5 ° C. or lower. Next, a solution obtained by dissolving 23.0 g of 3,5-dinitrobenzoyl chloride in 100 mL of tetrahydrofuran was slowly added dropwise over 30 minutes, and the mixture was returned to room temperature and reacted for 1 hour. After completion of the reaction, 500 mL of ethyl acetate and 500 mL of 1M aqueous hydrochloric acid solution were added for liquid separation, and the organic layer was further separated and washed three times with water, and then the organic layer was dried over magnesium sulfate and concentrated to precipitate crystals. By drying, 49.0 g of pale yellow crystals of the compound represented by the formula (1-4-1B) were obtained.

  Subsequently, in a 2 L three-necked flask equipped with a thermometer and a nitrogen introduction tube, 49.0 g of the compound represented by the above formula (1-4-1B), 2.48 g of 5% palladium carbon powder, 300 mL of tetrahydrofuran and 300 mL of ethanol. After that, 51 g of an 80% hydrazine monohydrate aqueous solution was slowly added, stirred at room temperature for 1 hour, heated to 70 ° C., and further reacted for 2 hours. After completion of the reaction, the filtrate obtained by removing palladium carbon by filtration was concentrated to about 200 mL, 500 mL of ethyl acetate was added, and the mixture was washed three times with water, and then the organic layer was concentrated and the precipitated crystals were filtered. By drying, 38.8 g of white crystals of the compound (D-4) represented by the above formula (1-4-1) was obtained.

<Synthesis of polymer (P1)>
[Polymerization Example 1: Synthesis of polyimide (PI-1)]
2,2.4 g (0.1 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride (TCA) as tetracarboxylic dianhydride, 7.5 g (0.07 mol) of p-phenylenediamine (PDA) as diamine ), 13.8 g (0.03 mol) of compound (D-1) is dissolved in 175 g of N-methyl-2-pyrrolidone (NMP), reacted at 60 ° C. for 6 hours, and contains 20% by weight of polyamic acid. A solution was obtained. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 78 mPa · s.

  Next, 406 g of NMP was added to the obtained polyamic acid solution, 11.8 g of pyridine and 15.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration cyclization reaction, the solvent in the system was replaced with new NMP (by this operation, pyridine and acetic anhydride used in the dehydration cyclization reaction were removed from the system. The same shall apply hereinafter) to obtain an imidation ratio of about 62. A solution containing 22% by weight of polyimide (PI-1) was obtained. A small amount of the obtained polyimide solution was taken, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 44 mPa · s.

[Polymerization Example 2: Synthesis of polyimide (PI-2)]
22.5 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 7.6 g (0.07 mol) of PDA as a diamine, and 14.8 g (0.03 mol) of compound (D-2) were dissolved in 179 g of NMP. Reaction was performed at 60 degreeC for 6 hours, and the solution containing 20 weight% of polyamic acids was obtained. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 88 mPa · s.

  Next, 416 g of NMP was added to the obtained polyamic acid solution, 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 22% by weight of polyimide (PI-2) having an imidation ratio of about 65%. A small amount of the obtained polyimide solution was taken, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 49 mPa · s.

[Polymerization Example 3: Synthesis of polyimide (PI-3)]
22.4 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 7.5 g (0.07 mol) of PDA as a diamine, and 13.8 g (0.03 mol) of compound (D-3) were dissolved in 175 g of NMP. Reaction was performed at 60 degreeC for 6 hours, and the solution containing 20 weight% of polyamic acids was obtained. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 89 mPa · s.

  Next, 406 g of NMP was added to the obtained polyamic acid solution, 11.8 g of pyridine and 15.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 22% by weight of polyimide (PI-3) having an imidation ratio of about 67%. A small amount of the obtained polyimide solution was taken, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 49 mPa · s.

[Polymerization Example 4: Synthesis of polyimide (PI-4)]
22.5 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 7.6 g (0.07 mol) of PDA as a diamine, and 14.8 g (0.03 mol) of compound (D-4) were dissolved in 179 g of NMP. Reaction was performed at 60 degreeC for 6 hours, and the solution containing 20 weight% of polyamic acids was obtained. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 70 mPa · s.

  Next, 416 g of NMP was added to the obtained polyamic acid solution, 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 22% by weight of polyimide (PI-4) having an imidization ratio of about 63%. A small amount of the obtained polyimide solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 45 mPa · s.

[Polymerization Example 5: Synthesis of polyimide (PI-5)]
A solution containing 20% by weight of polyamic acid was obtained under the same composition and the same conditions as in Polymerization Example 1. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 75 mPa · s.
Next, 406 g of NMP was added to the obtained polyamic acid solution, 13.4 g of pyridine and 17.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 22% by weight of polyimide (PI-5) having an imidation ratio of about 76%. A small amount of the obtained polyimide solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 55 mPa · s.

[Polymerization Example 6: Synthesis of polyimide (PI-6)]
2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride (BODA) 25.0 g (0.1 mol) as tetracarboxylic dianhydride , 7.6 g (0.07 mol) of PDA as a diamine and 14.7 g (0.03 mol) of compound (D-2) were dissolved in 189 g of NMP, reacted at 60 ° C. for 8 hours, and contained 20% by weight of polyamic acid. A solution was obtained. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 36 mPa · s.
Next, 439 g of NMP was added to the obtained polyamic acid solution, 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 22% by weight of polyimide (PI-6) having an imidation ratio of about 64%. A small amount of the obtained polyimide solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 30 mPa · s.

[Polymerization Example 7: Synthesis of polyimide (PI-7)]
18.9 g (0.075 mol) of BODA as tetracarboxylic dianhydride and 4.9 g (0.025 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CB) and 7.6 g of PDA as diamine (0.07 mol) and 14.8 g (0.03 mol) of compound (D-2) were dissolved in 185 g of NMP and reacted at 60 ° C. for 8 hours to obtain a solution containing 20% by weight of polyamic acid. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 40 mPa · s.
Next, 429 g of NMP was added to the obtained polyamic acid solution, 11.9 g of pyridine and 15.4 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration and cyclization reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 22% by weight of polyimide (PI-7) having an imidation ratio of about 66%. A small amount of the obtained polyimide solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 29 mPa · s.

[Polymerization Example 8: Synthesis of polyimide (PI-8)]
As tetracarboxylic dianhydride, 22.3 g (0.1 mol) of TCA, 5.4 g (0.05 mol) of PDA as diamine, and 24.4 g (0.05 mol) of compound (D-2) were dissolved in 209 g of NMP. Reaction was performed at 60 degreeC for 6 hours, and the solution containing 20 weight% of polyamic acids was obtained. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 55 mPa · s.
Next, 484 g of NMP was added to the obtained polyamic acid solution, 7.9 g of pyridine and 10.2 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 22% by weight of polyimide (PI-8) having an imidation ratio of about 50%. A small amount of the obtained polyimide solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 36 mPa · s.

[Comparative Polymerization Example 1: Synthesis of polyimide (PI-9)]
22.4 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 7.6 g (0.07 mol) of PDA as diamine, and 11.3 g (0.03 mol) of 4-octadecyloxy-1,3-diaminobenzene It melt | dissolved in 165g of NMP, it reacted at 60 degreeC for 6 hours, and obtained the solution containing 20 weight% of polyamic acids. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 99 mPa · s.
Next, 384 g of NMP was added to the obtained polyamic acid solution, 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 22% by weight of polyimide (PI-9) having an imidation ratio of about 69%. A small amount of the obtained polyimide solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 67 mPa · s.

[Comparative Polymerization Example 2: Synthesis of Polyimide (PI-10)]
TCA 22.4 g (0.1 mol) as tetracarboxylic dianhydride, 7.6 g (0.07 mol) PDA as diamine, 1,3-diamino-4- {4- [trans-4- (trans-4- 13.0 g (0.03 mol) of n-pentylcyclohexyl) cyclohexyl] phenoxy} benzene was dissolved in 172 g of NMP and reacted at 60 ° C. for 6 hours to obtain a solution containing 20% by weight of polyamic acid. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 59 mPa · s.
Next, 400 g of NMP was added to the obtained polyamic acid solution, 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 22% by weight of polyimide (PI-10) having an imidation ratio of about 62%. A small amount of the obtained polyimide solution was taken, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 40 mPa · s.

[Comparative Polymerization Example 3: Synthesis of Polyimide (PI-11)]
A solution containing 20% by weight of polyamic acid was obtained under the same composition and the same conditions as in Comparative Polymerization Example 10. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 62 mPa · s.
Next, 400 g of NMP was added to the obtained polyamic acid solution, 13.5 g of pyridine and 17.4 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 22% by weight of polyimide (PI-11) having an imidation ratio of about 74%. A small amount of the obtained polyimide solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 42 mPa · s.

<Preparation and evaluation of liquid crystal aligning agent>
[Example 1]
(1) Preparation of liquid crystal aligning agent In a solution containing polyimide (PI-1) as a polymer, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane (E-1) is used as an epoxy compound. 5 parts by weight with respect to 100 parts by weight of polyimide (PI-1) contained in the above solution, NMP and ethylene glycol mono-n-butyl ether (BC) are further added as solvents, and the solvent composition is NMP: BC. = 60:40 (weight ratio), solid content concentration 3.5 wt% solution. A liquid crystal aligning agent (S-1) was prepared by filtering this solution using a filter having a pore diameter of 1 μm.

(2) Manufacture of liquid crystal display element for vertical alignment evaluation A liquid crystal aligning agent (S-1) is apply | coated with the spinner on the transparent conductive film which consists of an ITO film | membrane provided in one surface of the glass substrate of thickness 1mm, Pre-baking was performed at 80 ° C. for 1 minute on a hot plate and heating was performed at 200 ° C. for 60 minutes to form a coating film having a thickness of 0.08 μm.
The coating film was rubbed with a rubbing machine having a roll around which a rayon cloth was wound at a roll rotation speed of 400 rpm, a stage moving speed of 3 cm / sec, and a hair foot indentation length of 0.4 mm. Then, ultrasonic cleaning was performed in ultrapure water for 1 minute, and then drying was performed in a 200 ° C. clean oven for 10 minutes to obtain a substrate having a rubbing-treated liquid crystal alignment film. This operation was repeated to obtain a pair (two) of substrates having a liquid crystal alignment film.
Next, after applying an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 3.5 μm to the outer edges of the pair of substrates having the liquid crystal alignment film, the liquid crystal alignment film surfaces are superposed and pressure-bonded so as to be antiparallel. The adhesive was cured. Next, a nematic liquid crystal (MLC-6608, manufactured by Merck & Co., Inc.) is filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port is sealed with an acrylic photo-curing adhesive to form a liquid crystal cell. A liquid crystal display element for vertical alignment evaluation was manufactured by attaching polarizing plates to both sides of the cell.

(3) Evaluation of vertical alignment The pretilt angle of the liquid crystal display element for vertical alignment evaluation was measured by the crystal rotation angle method. In the evaluation, the case where the pretilt angle was 87 ° or more was regarded as “good” for the vertical alignment, and the case where it was less than 87 ° was regarded as “poor” for the vertical alignment. The evaluation results are shown in Table 1 below.
In manufacturing a liquid crystal display element for evaluating the vertical alignment, a rubbing process was performed on the coating film formed on the substrate. This rubbing process diminishes the vertical alignment regulating force of the liquid crystal alignment film. It is known to be effective. Therefore, when a pretilt angle of 87 ° or more is exhibited despite the rubbing treatment, it can be said that the liquid crystal alignment film has extremely excellent vertical alignment of liquid crystal molecules. Further, it has been empirically clarified that the liquid crystal aligning agent giving such a result hardly causes display unevenness (ODF unevenness) even when used for manufacturing a vertical alignment type liquid crystal display element by the ODF method.

(4) Manufacture of liquid crystal display element for evaluating voltage holding ratio Manufacture of liquid crystal display element for evaluating vertical alignment, except that the formed coating film was not subjected to rubbing treatment and subsequent cleaning and drying treatment. A liquid crystal display element for evaluating the voltage holding ratio was manufactured by the same method as in the case of performing the above.

(5) Evaluation of voltage holding ratio A voltage of 1 V was applied to the manufactured liquid crystal display element for voltage holding ratio evaluation at 60 ° C. with a 60 microsecond application time and a 1670 microsecond span. The voltage holding ratio VHR [%] after 1670 milliseconds from the release was measured. The measurement was performed using Toyo Technica VHR-1. The measurement results are shown in Table 1 below.

(6) Evaluation of Reworkability of Liquid Crystal Alignment Film A liquid crystal alignment agent (S-1) is applied by a spinner on a transparent conductive film made of ITO provided on one surface of a 1 mm thick glass substrate, and 100 on a hot plate. Pre-baking was performed at 90 ° C. for 90 seconds to form a coating film having a thickness of about 80 nm. This operation was repeated to prepare two substrates with a coating film. Next, the two obtained substrates were stored in a dark room at 25 ° C. under a nitrogen atmosphere. After 12 hours and 48 hours from the start of storage, each substrate is taken out, immersed in a beaker containing NMP adjusted to 40 ° C. for 2 minutes, washed several times with ultrapure water, and then air blown. Water droplets on the surface were removed. About this board | substrate, the peeling ease (rework property) from the board | substrate of a liquid crystal aligning film was evaluated by investigating the presence or absence of the coating film residue by observing with an optical microscope. Evaluation is that the substrate is taken out after 48 hours from the start of storage, when the coating residue is not observed after NMP immersion, the rework property is “excellent”, and the coating residue is observed on the substrate after 48 hours However, when the substrate was not observed on the substrate after 12 hours, the reworkability was “good”, and when the coating film residue was observed on the substrate after 12 hours, the reworkability was “bad”. The evaluation results are shown in Table 1 below.
(7) Evaluation of light resistance The initial voltage holding ratio was measured on the liquid crystal display element manufactured above under the same conditions as the evaluation of the voltage holding ratio. Thereafter, the electrode was placed at a distance of 5 cm under a 100 watt type white fluorescent lamp, irradiated with light for 500 hours, and then the voltage holding ratio was measured again under the same conditions as described above. When the decrease rate of the voltage holding ratio compared with the initial value is 1% or less, the light resistance “A”, when it exceeds 1% and 2% or less, “B”, when it exceeds 2% Light resistance “C”.

[Examples 2 to 10, Comparative Examples 1 to 4]
While preparing the liquid crystal aligning agents (S-2) to (S-14) in the same manner as in Example 1, except that the type of polymer and the content of the epoxy compound were changed as shown in Table 1 below, Each evaluation of vertical orientation, voltage holding ratio, reworkability, and light resistance was performed. The results are shown in Table 1 below.

As shown in Table 1, all of the liquid crystal aligning agents of the examples had a high pretilt angle of 87 ° or more in the formed liquid crystal alignment film, and were excellent in the vertical alignment of liquid crystal molecules. In the examples, the pretilt angle was high despite the rubbing treatment performed on the coating film formed on the substrate. Therefore, when the vertical alignment type liquid crystal display element was manufactured by the ODF method. It can also be said that the occurrence of display unevenness can be suitably suppressed. Moreover, in the thing of an Example, while light resistance was favorable, it was favorable also about the rework property also when an epoxy compound is contained in a liquid crystal aligning agent.
In addition, the voltage holding ratio is good in the examples, and among them, Examples 1, 3, 5, and 5 containing polyimide (PI-1), (PI-3) or (PI-5) as the polymer component. 10 showed a high voltage holding ratio of 98.0% or more.
On the other hand, in Comparative Examples 1 to 3, the reworkability was good, but the vertical alignment and light resistance were poor. In Comparative Example 4, although the vertical alignment property and light resistance were good, the reworkability was poor.

Claims (9)

A liquid crystal aligning agent comprising at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, polyimide and polyorganosiloxane,
A liquid crystal aligning agent comprising a polymer (P1) having a group represented by the following formula (0) as the polymer.

(In the formula (0), Ac ¹ and Ac ² are independently a cyclohexane ring or a benzene ring, which may have a substituent .R ¹ is a hydrogen atom or a C1-20 a is .X is an alkyl group, an oxygen atom, + - CO-O -, + - O-CO -, + - O-CH 2 -, + - CH 2 -O -, + - CO-S -, + -S-CO-, + -CONH- or + -NHCO- (where "+" represents a bond with a phenylene group), n ¹ is 1 or 2, and n ² is 0 or (However, when n ¹ is 2, a plurality of Ac ¹ are each independently defined above. M is an integer of ¹ to 3. “*” represents a bond.) The polymer (P1) is obtained by reacting at least one compound selected from the group consisting of a tetracarboxylic dianhydride and a tetracarboxylic acid diester compound and a diamine containing a compound represented by the following formula (1). The liquid crystal aligning agent according to claim 1, which is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide obtained.

(In the formula (1), Ac ¹ and Ac ² are independently a cyclohexane ring or a benzene ring, which may have a substituent .R ¹ is a hydrogen atom or a C1-20 a is .X is an alkyl group, an oxygen atom, + - CO-O -, + - O-CO -, + - O-CH 2 -, + - CH 2 -O -, + - CO-S -, + -S-CO-, + -CONH- or + -NHCO- (where "+" represents a bond to a phenylene group) n ¹ is 1 or 2 and n ² is 0 or 1 (However, when n ¹ is 2, a plurality of Ac ¹ are independently defined above. M is an integer of ¹ to 3.) The liquid crystal aligning agent according to claim ¹ , wherein the sum of n ¹ and n ² is 2 or 3. 4. The liquid crystal aligning agent according to claim ¹ , wherein the sum of n ¹ and n ² is 2. 5.   The X is an oxygen atom, + -CO-O- or + -O-CO- (where "+" represents a bond with a phenylene group). The liquid crystal aligning agent of description.   The liquid crystal aligning film formed using the liquid crystal aligning agent as described in any one of Claims 1 thru | or 5.   A liquid crystal display device comprising the liquid crystal alignment film according to claim 6. A polymer obtained by reacting at least one compound selected from the group consisting of a tetracarboxylic dianhydride and a tetracarboxylic acid diester compound with a diamine containing a compound represented by the following formula (1).

(In the formula (1), Ac ¹ and Ac ² are independently a cyclohexane ring or a benzene ring, which may have a substituent .R ¹ is a hydrogen atom or a C1-20 a is .X is an alkyl group, an oxygen atom, + - CO-O -, + - O-CO -, + - O-CH 2 -, + - CH 2 -O -, + - CO-S -, + -S-CO-, + -CONH- or + -NHCO- (where "+" represents a bond to a phenylene group) n ¹ is 1 or 2 and n ² is 0 or 1 (However, when n ¹ is 2, a plurality of Ac ¹ are independently defined above. M is an integer of ¹ to 3.) A compound represented by the following formula (1).

(In the formula (1), Ac ¹ and Ac ² are independently a cyclohexane ring or a benzene ring, which may have a substituent .R ¹ is a hydrogen atom or a C1-20 a is .X is an alkyl group, an oxygen atom, + - CO-O -, + - O-CO -, + - O-CH 2 -, + - CH 2 -O -, + - CO-S -, + -S-CO-, + -CONH- or + -NHCO- (where "+" represents a bond to a phenylene group) n ¹ is 1 or 2 and n ² is 0 or 1 (However, when n ¹ is 2, a plurality of Ac ¹ are independently defined above. M is an integer of ¹ to 3.)