JP6460342B2 - Liquid crystal aligning agent and liquid crystal display element using the same - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent used for manufacturing a liquid crystal display element, a liquid crystal aligning film obtained from the liquid crystal aligning agent, and a liquid crystal display element using the liquid crystal aligning film.

  A liquid crystal display element is known as a lightweight, thin, and low power consumption display device. In recent years, high-definition liquid crystal display elements for mobile phones and tablet terminals, which have rapidly expanded their market share, have made remarkable developments that require high display quality.

  A liquid crystal display element is configured by sandwiching a liquid crystal layer between a pair of transparent substrates provided with electrodes. In the liquid crystal display element, an organic film made of an organic material is used as the liquid crystal alignment film so that the liquid crystal is in a desired alignment state between the substrates. That is, the liquid crystal alignment film is a constituent member of the liquid crystal display element, and is formed on a surface of the substrate that holds the liquid crystal in contact with the liquid crystal, and plays a role of aligning the liquid crystal in a certain direction between the substrates. The liquid crystal alignment film plays a major role in the liquid crystal display element because it determines the alignment uniformity of the liquid crystal molecules and the pretilt angle with respect to the substrate and has a great influence on the electrical characteristics of the display element.

  Of these, the pretilt angle of the liquid crystal is one of the important parameters that influence the display characteristics, and is required to be controlled to an appropriate value according to the mode of the liquid crystal display element. For example, in a mode called IPS (In Plane Switching) or FFS (Fringe Field Switching), the lower the pretilt angle, the wider the viewing angle and the better the color reproducibility. As a liquid crystal alignment film characterized in that a low pretilt angle can be obtained, one having an alkylene structure in a polyimide main chain is known (see Patent Documents 1 and 2).

JP-A-10-123532 JP 2000-80164 A

  However, in recent years, with higher performance of cellular phones and tablet terminals, not only good orientation but also a lower pretilt angle is required. On the other hand, a liquid crystal alignment film containing a polyamic acid or polyamic acid ester using 1,2-bis (4-aminophenoxy) ethane as a diamine component is significantly low in comparison with good alignment and conventional techniques. Realizing a pretilt angle has been understood by the inventors, but such polyamic acid or polyamic acid ester is one of the main solvents of liquid crystal aligning agents, and has excellent printability and thickening properties, and is regulated by law. It was also found that the solubility in γ-butyrolactone was poor. An object of the present invention is to provide a liquid crystal aligning agent that realizes good liquid crystal alignment and a low pretilt angle and has high solubility in γ-butyrolactone.

  As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, the gist of the present invention is as follows.

1. A diamine component containing a diamine of the following formulas (1) and (2) and a polyimide precursor obtained by a reaction with a tetracarboxylic acid derivative and at least one polymer selected from a polyimide obtained by imidizing the polyimide precursor Liquid crystal aligning agent to contain.

式（２）中のｎは、１，３又は５の整数である。

N in Formula (2) is an integer of 1, 3 or 5.

2. The liquid crystal aligning agent of said 1 whose diamine of the said Formula (1) is 10-90 mol% in a diamine component.

3. The liquid crystal aligning agent of said 1, 2 whose diamine of the said Formula (2) is 10-90 mol% in a diamine component.

4). 5. The liquid crystal aligning agent according to any one of 1 to 4, wherein the tetracarboxylic acid derivative contains an aliphatic structure or an alicyclic group structure in the structure.

5. Liquid crystal alignment as described in any one of said 1 to 4 whose tetracarboxylic acid derivative containing an aliphatic structure or alicyclic group structure in a structure is 10-100 mol% in all the tetracarboxylic acid derivatives. Agent.

6). 6. The liquid crystal aligning agent according to any one of 1 to 5, wherein the carboxylic acid derivative is a dicarboxylic acid diester.

7). The liquid crystal aligning film obtained by apply | coating and baking the liquid crystal aligning agent as described in any one of said 1-6 to a board | substrate.

8). 8. A liquid crystal display device having the liquid crystal alignment film as described in 7 above.

  By using the liquid crystal aligning agent of the present invention, a liquid crystal display element having both good liquid crystal orientation and low pretilt angle characteristics can be manufactured, and therefore, it can be suitably used for a large screen and high definition liquid crystal display. In addition, since the polymer used in the liquid crystal aligning agent of the present invention has good solubility in γ-butyrolactone, the liquid crystal aligning agent of the present invention has good storage stability, printability and thickening. Excellent characteristics.

<Specific diamine>
The liquid crystal aligning agent of this invention is chosen from the polyimide precursor obtained by imidating the polyimide precursor obtained by reaction with the diamine component containing the diamine of following formula (1) and (2), and a tetracarboxylic acid derivative. It is a liquid crystal aligning agent containing at least one polymer.

式（２）中のｎは、１，３又は５の整数である。

N in Formula (2) is an integer of 1, 3 or 5.

  In the polymer, the polyamic acid ester using the diamine of the formula (1) contributes to the improvement of liquid crystal orientation and low pretilt angle characteristics, but has little contribution to the improvement of solubility in γ-butyrolactone.

  On the other hand, the polyamic acid ester using the diamine of the formula (2) contributes to the improvement of the solubility of the polymer, but has little contribution to the low pretilt angle characteristics and the liquid crystal orientation.

  That is, at least one polymer selected from a polyamic acid ester obtained by reaction of a diamine component containing the diamine of formula (1) and formula (2) and a dicarboxylic acid diester and a polyimide obtained by imidizing it. Can satisfy the above three characteristics at the same time.

  10-90 mol% is preferable in the total diamine component, and, as for the diamine of Formula (1), 10-70 mol% is more preferable.

  10-90 mol% is preferable in all the diamine components, and, as for the diamine of Formula (2), 30-90 mol% is more preferable.

<Polymer>
The polyimide precursor obtained by reaction of the diamine component containing the diamines of the above formulas (1) and (2) and the tetracarboxylic acid derivative can be expressed as follows.

In formula (3), Y is a divalent organic group derived from a diamine component, X is a tetravalent organic group derived from a tetracarboxylic acid derivative, and A ¹ and A ² are each independently a hydrogen atom, or C1-C10 alkyl group which may have a substituent, C1-C10 alkenyl group which may have a substituent, C1-C10 alkynyl group which may have a substituent R ¹ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and at least a part of Y has a structure of the following formulas (4) and (5).

式（５）中、ｎは１，３又は５の整数である。

In formula (5), n is an integer of 1, 3 or 5.

<Tetracarboxylic acid derivative>
Examples of the tetracarboxylic acid derivative used for the synthesis of the liquid crystal aligning agent of the present invention include tetracarboxylic dianhydride, tetracarboxylic monoanhydride, tetracarboxylic acid, dicarboxylic acid dialkyl ester, and dicarboxylic acid chloride dialkyl ester. If the reaction with diamine proceeds, it is not limited to these.

  In the formula (3), X is a tetravalent organic group derived from a tetracarboxylic acid derivative, and its structure is not particularly limited. If a specific example of X is intentionally shown, the following X-1 to X-44 can be mentioned.

In formula (X-1), R ^{2 to} R ⁵ each independently represents a hydrogen atom, a methyl group or a phenyl group.

  In Formula (3), X may be one type or two or more types may be mixed, but at least one type of X having an alicyclic structure or an aliphatic structure is included. Is preferred. A preferred ratio of X having an alicyclic structure or an aliphatic structure is 10 mol% or more of X, more preferably 30 mol% or more, and further preferably 50 mol% or more.

  As the structure of X having an alicyclic structure or an aliphatic structure, (X-1) to (X-16), (X-23) to (X-27), (X-41) to (X-43) (X-1), (X-7), (X-9), (X-23) and (X-24) are particularly preferable.

In the formula (3), specific examples of the alkyl group in R ¹ include methyl, ethyl, propyl, i-propyl, n-butyl, i-butyl, s-butyl, and t-butyl. Group, n-pentyl group and the like.

In Formula (3), A ¹ and A ² are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms that may have a substituent, or an alkyl group having 1 to 10 carbon atoms that may have a substituent. Or an alkynyl group having 1 to 10 carbon atoms which may have a substituent.

Specific examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, t-butyl group, hexyl group, octyl group, decyl group, cyclopentyl group, cyclohexyl group, and bicyclohexyl group. Examples of the alkenyl group include those obtained by replacing one or more CH—CH structures present in the above alkyl group with C═C structures, and more specifically, vinyl groups, aryl groups, 1-propenyl groups. , Isopropenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group, 2-hexenyl group, cyclopropenyl group, cyclopentenyl group, cyclohexenyl group and the like. Alkynyl groups include those in which one or more CH ₂ —CH ₂ structures present in the alkyl group are replaced with C≡C structures, and more specifically, ethynyl groups, 1-propynyl groups, 2 -A propynyl group etc. are mentioned.

  The above alkyl group, alkenyl group, and alkynyl group may have a substituent, and may further form a ring structure by the substituent. Note that forming a ring structure with a substituent means that the substituents or a substituent and a part of the mother skeleton are bonded to form a ring structure.

  Examples of this substituent include halogen groups, hydroxyl groups, thiol groups, nitro groups, aryl groups, organooxy groups, organothio groups, organosilyl groups, acyl groups, ester groups, thioester groups, phosphate ester groups, amide groups, alkyls. A group, an alkenyl group and an alkynyl group.

  Examples of the halogen group as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  A phenyl group is mentioned as an aryl group which is a substituent. This aryl group may be further substituted with the other substituent described above.

  The organooxy group which is a substituent can have a structure represented by OR. The R may be the same or different, and examples thereof include the alkyl group, alkenyl group, alkynyl group, and aryl group described above. These Rs may be further substituted with the substituent described above. Specific examples of the organooxy group include methoxy group, ethoxy group, propyloxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group and the like.

  As the organothio group which is a substituent, the structure represented by -S-R can be shown. Examples of R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These Rs may be further substituted with the substituent described above. Specific examples of the organothio group include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, and an octylthio group.

As the organosilyl group which is a substituent, a structure represented by -Si- (R) ₃ can be shown. The R may be the same or different, and examples thereof include the alkyl group, alkenyl group, alkynyl group, and aryl group described above. These Rs may be further substituted with the substituent described above. Specific examples of the organosilyl group include a trimethylsilyl group, a triethylsilyl group, a tripropylsilyl group, a tributylsilyl group, a tripentylsilyl group, a trihexylsilyl group, a pentyldimethylsilyl group, and a hexyldimethylsilyl group.

  As an acyl group which is a substituent, the structure represented by -C (O) -R can be shown. Examples of R include the above-described alkyl group, alkenyl group, and aryl group. These Rs may be further substituted with the substituent described above. Specific examples of the acyl group include formyl group, acetyl group, propionyl group, butyryl group, isobutyryl group, valeryl group, isovaleryl group, benzoyl group and the like.

  As an ester group which is a substituent, the structure represented by -C (O) O-R or -OC (O) -R can be shown. Examples of R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These Rs may be further substituted with the substituent described above.

  As a thioester group which is a substituent, the structure represented by -C (S) O-R or -OC (S) -R can be shown. Examples of R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These Rs may be further substituted with the substituent described above.

As a phosphate group which is a substituent, the structure represented by -OP (O)-(OR) ₂ can be shown. The R may be the same or different, and examples thereof include the alkyl group, alkenyl group, alkynyl group, and aryl group described above. These Rs may be further substituted with the substituent described above.

As the amide group as a substituent, —C (O) NH ₂ , or —C (O) NHR, —NHC (O) R, —C (O) N (R) ₂ , —NRC (O) R The structure represented by can be shown. The R may be the same or different, and examples thereof include the alkyl group, alkenyl group, alkynyl group, and aryl group described above. These Rs may be further substituted with the substituent described above.

  Examples of the aryl group as a substituent include the same aryl groups as described above. This aryl group may be further substituted with the other substituent described above.

  Examples of the alkyl group as a substituent include the same alkyl groups as described above. This alkyl group may be further substituted with the other substituent described above.

  Examples of the alkenyl group as a substituent include the same alkenyl groups as described above. This alkenyl group may be further substituted with the other substituent described above.

  Examples of the alkynyl group that is a substituent include the same alkynyl groups as described above. This alkynyl group may be further substituted with the other substituent described above.

In general, when a bulky structure is introduced, there is a possibility that the reactivity of the amino group and the liquid crystal orientation may be lowered. Therefore, as A ¹ and A ² , a hydrogen atom or a carbon atom that may have a substituent is 1 The alkyl group of ˜5 is more preferable, and a hydrogen atom, a methyl group or an ethyl group is particularly preferable.

<Other diamines>
In Formula (3), at least a part of Y is a structure of Formula (4) and Formula (5), but Y is not limited to them, and may include other structures. The following Y-1 to Y-115 may be mentioned as specific examples of other Y structures.

（式（Ｙ−１０２）中、ｍ、ｎはそれぞれ１から１１の整数であり、ｍ＋ｎは２から１２の整数であり、式（Ｙ−１０７）中、ｈは１〜３の整数であり、式（Ｙ−１０４）及び（Ｙ−１１１）中、ｊは０から３の整数である。式（Ｙ−１１３）〜式（Ｙ−１１５）中、Ｂｏｃはｔ−ブトキシカルボニル基である。）

(In Formula (Y-102), m and n are each an integer of 1 to 11, m + n is an integer of 2 to 12, and in Formula (Y-107), h is an integer of 1 to 3, In formulas (Y-104) and (Y-111), j is an integer from 0 to 3. In formulas (Y-113) to (Y-115), Boc is a t-butoxycarbonyl group.

  Of these, Y-7, Y-21, Y-22, Y-23, Y-25, Y-26, Y-27, Y-43, Y-44, Y-45, Y-46, Y- Highly linear structures such as 48, Y-56, Y-64, Y-66, Y-67, Y-68, Y-91, Y-92, and Y-93 have liquid crystal alignment films. The orientation can be increased. Moreover, Y-69, Y-70, Y-71, Y-72, Y-73, Y-74, Y-75, Y-76, Y-77, Y-78, Y-79, Y-80, Long chain alkyl groups in the side chain such as Y-81, Y-82, Y-83, Y-84, Y-85, Y-86, Y-87, Y-88, Y-89, Y-90 , An aromatic ring, an aliphatic ring, a steroid skeleton, or a combination of these structures can increase the pretilt angle of liquid crystal when a liquid crystal alignment film is formed. Moreover, a structure such as Y-112 can obtain good rubbing resistance when a liquid crystal alignment film is formed.

  The polyimide precursor used in the present invention is obtained from a reaction between a diamine component and a tetracarboxylic acid derivative, and examples thereof include polyamic acid and polyamic acid ester.

<Method for producing polyamic acid>
The polyamic acid which is a polyimide precursor used in the present invention can be synthesized by the following method.

  Specifically, tetracarboxylic dianhydride and diamine are reacted in the presence of an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C. for 30 minutes to 24 hours, preferably 1 to 12 hours. Can be synthesized.

  The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the solubility of the monomer and polymer, and these are used alone or in combination. May be. The concentration of the polymer is preferably 1 to 30% by mass and more preferably 5 to 20% by mass from the viewpoint that the polymer is hardly precipitated and a high molecular weight body is easily obtained.

  The polyamic acid obtained as described above can be recovered by precipitating the polymer by pouring into the poor solvent while thoroughly stirring the reaction solution. Moreover, the powder of polyamic acid refine | purified by performing precipitation several times, washing | cleaning with a poor solvent, and normal temperature or heat-drying can be obtained. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene etc. are mentioned.

<Method for producing polyamic acid ester>
The polyamic acid ester which is a polyimide precursor used in the present invention can be synthesized by the following methods (1) to (3).

(1) When synthesizing from polyamic acid The polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from tetracarboxylic dianhydride and diamine.

  Specifically, the polyamic acid and the esterifying agent are reacted in the presence of an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C., for 30 minutes to 24 hours, preferably 1 to 4 hours. Can be synthesized.

  As the esterifying agent, those that can be easily removed by purification are preferred, and N, N-dimethylformamide dimethyl acetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide Dineopentyl butyl acetal, N, N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p -Tolyltriazene, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride and the like. The addition amount of the esterifying agent is preferably 2 to 6 molar equivalents per 1 mol of the polyamic acid repeating unit.

  The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the solubility of the polymer, and these may be used alone or in combination of two or more. Good. 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.

(2) When synthesizing by reaction of dicarboxylic acid diester dichloride and diamine Polyamic acid ester can be synthesized from dicarboxylic acid diester dichloride and diamine.

  Specifically, dicarboxylic acid diester dichloride and diamine are reacted in the presence of a base and an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C. for 30 minutes to 24 hours, preferably 1 to 4 hours. Can be synthesized.

  As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferable because the reaction proceeds gently. The addition amount of the base is preferably 2 to 4 moles relative to the dicarboxylic acid diester dichloride from the viewpoint of easy removal and high molecular weight.

  The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone from the solubility of the monomer and polymer, and these may be used alone or in combination. The polymer 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 hardly occurs and a high molecular weight body is easily obtained. Further, in order to prevent hydrolysis of dicarboxylic acid diester dichloride, the solvent used for the synthesis of polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent mixing of outside air in a nitrogen atmosphere.

(3) When a polyamic acid is synthesized from a dicarboxylic acid diester and a diamine The polyamic acid ester can be synthesized by polycondensation of a dicarboxylic acid diester and a diamine.

  Specifically, dicarboxylic acid diester and diamine are reacted in the presence of a condensing agent, a base and an organic solvent at 0 ° C. to 150 ° C., preferably 0 ° C. to 100 ° C., for 30 minutes to 24 hours, preferably 3 to 15 hours. Can be synthesized.

  Examples of the condensing agent include triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N′-carbonyldiimidazole, dimethoxy-1,3,5-triazi Nylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N , N ′, N′-tetramethyluronium hexafluorophosphate, diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate, and the like can be used. It is preferable that the addition amount of a condensing agent is 2-3 times mole with respect to dicarboxylic acid diester.

  As the base, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the base is preferably 2 to 4 moles relative to the diamine component from the viewpoint that it can be easily removed and a high molecular weight product can be easily obtained.

  In the above reaction, 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 to 1.0 times the mole of the diamine component.

  Among the three polyamic acid ester synthesis methods, a high molecular weight polyamic acid ester is obtained, and therefore the synthesis method (3) is particularly preferable.

  The polyamic acid ester solution obtained as described above can be polymerized by pouring into a poor solvent while stirring well. Precipitation is performed several times, and after washing with a poor solvent, a purified polyamic acid ester powder can be obtained at room temperature or by heating and drying. Although a poor solvent is not specifically limited, Water, methanol, isopropyl alcohol, ethanol, hexane, butyl cellosolve, acetone, toluene, etc. are mentioned.

<Method for producing imidized polymer>
The imidized polymer used in the present invention can be produced by imidizing the polyimide precursor. When an imidized polymer is produced from a polyimide precursor, chemical imidization in which a basic catalyst is added to the polyimide precursor solution is simple. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer does not easily decrease during the imidization process.

  Chemical imidation can be performed by stirring a polyimide precursor to be imidized in an organic solvent in the presence of a basic catalyst. As an organic solvent, the solvent used at the time of the polymerization reaction mentioned above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, triethylamine and pyridine are preferable because they have 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 temperature at which the imidization reaction is performed is -20 ° C to 140 ° C, preferably 0 ° C to 100 ° C, and the reaction time can be 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times of the polyimide precursor. The imidation ratio of the resulting polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. Since the added catalyst or the like remains in the solution after the imidation reaction, the obtained imidized polymer is recovered by the means described below, redissolved in an organic solvent, and the liquid crystal alignment according to the present invention. It is preferable to use an agent.

  The solution of the imidized polymer obtained as described above can be precipitated by pouring into a poor solvent while stirring well. Precipitation is performed several times, and after washing with a poor solvent, an imidized polymer powder purified by drying at normal temperature or by heating can be obtained.

  The poor solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene.

<Liquid crystal aligning agent>
The liquid crystal aligning agent used in the present invention has a form of a solution in which the aforementioned polyimide precursor or an imidized polymer thereof (hereinafter referred to as a polymer having a specific structure) is dissolved in an organic solvent. The molecular weight of the polymer having a specific structure is preferably 2,000 to 500,000 in terms of weight average molecular weight, more preferably 5,000 to 300,000, and still more preferably 8,000 to 100,000. The number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and still more preferably 4,000 to 50,000.

  The concentration of the polymer of the liquid crystal aligning agent used in the present invention can be appropriately changed depending on the setting of the thickness of the coating film to be formed, but it is 1 weight from the viewpoint of forming a uniform and defect-free coating film. % From the viewpoint of storage stability of the solution, and preferably 10% by weight or less.

  The organic solvent contained in the liquid crystal aligning agent used for this invention will not be specifically limited if the polymer of a specific structure melt | dissolves uniformly. Specific examples thereof include N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, Examples include 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl sulfoxide, dimethyl sulfone, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, 3-methoxy-N, N-dimethylpropanamide and the like. You may use these 1 type or in mixture of 2 or more types. Moreover, even if it is a solvent which cannot melt | dissolve a polymer uniformly independently, if it is a range which a polymer does not precipitate, you may mix with said organic solvent.

  The liquid crystal aligning agent used for this invention contains the solvent for improving the coating-film uniformity at the time of apply | coating a liquid crystal aligning agent to a board | substrate other than the organic solvent for dissolving the polymer of a specific structure. Also good. As such a solvent, a solvent having a surface tension lower than that of the organic solvent is generally used. Specific examples thereof include ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 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-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, butyl cellosolve acetate, di Propylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl ester, lactic acid Isoamyl ester, and the like. Two or more of these solvents may be used in combination.

  In the liquid crystal aligning agent of the present invention, in addition to the above, as long as the effects of the present invention are not impaired, a polymer other than the polymer described in the present invention, the electrical properties such as the dielectric constant and conductivity of the liquid crystal aligning film Dielectric or conductive material for changing characteristics, silane coupling agent for improving adhesion between liquid crystal alignment film and substrate, crosslinkability for increasing hardness and density of liquid crystal alignment film When firing the compound, and further, the coating film, an imidization accelerator for the purpose of efficiently proceeding imidization by heating of the polyimide precursor may be added.

<Liquid crystal alignment film>
The liquid crystal alignment film of the present invention is a film obtained by applying the liquid crystal aligning agent to a substrate, drying and baking. The substrate on which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, a silicon nitride substrate, an acrylic substrate, a polycarbonate substrate such as a polycarbonate substrate, or the like can be used. From the viewpoint of simplification of the process, it is preferable to use a substrate on which an electrode or the like is formed. In the reflective liquid crystal display element, an opaque material such as a silicon wafer can be used as long as only one substrate is used. In this case, a material that reflects light, such as aluminum, can also be used.

  Examples of the method for applying the liquid crystal aligning agent of the present invention include a spin coating method, a printing method, and an ink jet method. Arbitrary temperature and time can be selected for the drying and baking steps after applying the liquid crystal aligning agent of the present invention. Usually, in order to sufficiently remove the organic solvent contained, the organic solvent is dried at 50 ° C. to 120 ° C. for 1 minute to 10 minutes, and then baked at 150 ° C. to 300 ° C. for 5 minutes to 120 minutes. The thickness of the coating film after baking is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may be lowered, so it is 5 to 300 nm, preferably 10 to 200 nm.

  Examples of a method for aligning the obtained liquid crystal alignment film include a rubbing method and a photo-alignment processing method.

  As a specific example of the photo-alignment treatment method, there is a method in which the surface of the coating film is irradiated with radiation deflected in a certain direction, and in some cases, a heat treatment is further performed at a temperature of 150 to 250 ° C. to impart liquid crystal alignment ability. Can be mentioned. As the radiation, ultraviolet rays and visible rays having a wavelength of 100 nm to 800 nm can be used.

[Liquid crystal display element]
The liquid crystal display element of the present invention is a liquid crystal display element obtained by a known method after obtaining a substrate with a liquid crystal alignment film from the liquid crystal aligning agent of the present invention by the above-described method and performing alignment treatment by rubbing treatment or the like. is there.

  The manufacturing method of the liquid crystal cell of the liquid crystal display element is not particularly limited. For example, a pair of substrates on which the liquid crystal alignment film is formed is arranged with the liquid crystal alignment film surface inside, preferably 1 to 30 μm, more preferably In general, a method is generally used in which a spacer of 2 to 10 μm is placed and then the periphery is fixed with a sealant, and liquid crystal is injected and sealed. The method for enclosing the liquid crystal is not particularly limited, and examples thereof include a vacuum method of injecting liquid crystal after reducing the pressure inside the produced liquid crystal cell, and a dropping method of sealing after dropping the liquid crystal. Since the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention as described above has excellent characteristics, liquid crystal display elements such as VA, TN, STN, TFT, and lateral electric field type, It can be used as a liquid crystal alignment film for ferroelectric and antiferroelectric liquid crystal display elements.

  The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.

The abbreviations of the compounds used in the examples and comparative examples, and the method of property evaluation are as follows.
X-1: 2,4-bis (methoxycarbonyl) cyclobutane-1,3-dicarboxylic acid X-2: 1,2,3,4-cyclobutanetetracarboxylic dianhydride Y-1: bis (4-aminophenoxy) ) Methane Y-2: 1,2-bis (4-aminophenoxy) ethane Y-3: 1,3-bis (4-aminophenoxy) propane Y-4: 1,5-bis (4-aminophenoxy) pentane Y-5: 1,3-bis (4-aminophenethyl) urea DBOP: diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate

  Below, each measuring method is shown.

[viscosity]
In the synthesis example, the viscosity of the polyamic acid solution or the polyamic acid ester solution is an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.). R24), measured at a temperature of 25 ° C.

[Solid content]
In the synthesis example, the solid content concentration of the polyamic acid solution or the polyamic acid ester solution was calculated as follows.

  About 1.1 g of the solution was weighed into an aluminum cup with a handle No. 2 (manufactured by ASONE), heated in an oven DNF400 (manufactured by Yamato) at 200 ° C. for 2 hours, and then allowed to stand at room temperature (23 ° C.) for 5 minutes. The weight of the solid content remaining in the cup was weighed. The solid content concentration was calculated from the solid content weight and the original solution weight value.

[Molecular weight]
The molecular weight of the polyamic acid and the polyamic acid ester is measured by a GPC (room temperature gel permeation chromatography) apparatus, and the number average molecular weight (hereinafter also referred to as Mn) and the weight average molecular weight (hereinafter also referred to as Mw) in terms of polyethylene glycol and polyethylene oxide. Say).
GPC device: manufactured by Shodex (GPC-101)
Column: manufactured by Shodex (series of KD803 and KD805)
Column temperature: 50 ° C
Eluent: N, N-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H 2 O) 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF ) Is 10ml / L)
Flow rate: 1.0 ml / min Standard sample for preparing calibration curve: TSK standard polyethylene oxide (weight average molecular weight (Mw) about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol (peak top molecular weight manufactured by Polymer Laboratories) (Mp) about 12,000, 4,000, 1,000). In order to avoid overlapping the peaks, two samples of 900,000, 100,000, 12,000, 1,000 mixed samples, and 150,000, 30,000, 4,000 mixed samples are measured separately.

[VHR aging resistance]
The produced liquid crystal cell was aged for 48 hours in an oven at 60 ° C. under an LED light source (10000 cd). The voltage holding ratio was measured before and after aging. The case of 90% or more before aging and 85% or more after aging was evaluated as ◯, and the one not satisfying the above characteristics was evaluated as ×.

-VHR measurement conditions-
A voltage of 1 V was applied for 60 μs, and the voltage after 100 ms was measured to calculate the fluctuation from the initial value as VHR (voltage holding ratio). The temperature of the liquid crystal cell was measured at 60 ° C.

[Liquid crystal orientation]
In a constant temperature environment of 60 ° C., an AC voltage with a relative transmittance of 100% at a frequency of 30 Hz was applied for 168 hours.

  Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left as it was at room temperature for one day.

  After leaving, the liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal, and the backlight is turned on with no voltage applied so that the brightness of the transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second area of the first pixel became darkest to the angle at which the first area became darkest was calculated as an angle Δ. Similarly, for the second pixel, the second region and the first region were compared, and a similar angle Δ was calculated. Then, the average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal cell. The case where the value of the angle Δ of this liquid crystal cell was less than 0.05 degrees was defined as ◯, and the case where it was 0.05 degrees or more was defined as x.

[Pretilt angle]
The pretilt angle was measured. For the measurement, an Axo Scan Mueller matrix polarimeter manufactured by Optometrics was used. When the pretilt is less than 1.0 °, the symbol “◯” is given, and when the pretilt is 1.0 ° or more, the symbol “x” is given.

[Solubility of GBL (γ-butyrolactone)]
Using the polyamic acid solution or the polyamic acid ester powder obtained in Synthesis Examples 1 to 10, the polymer solid content: 6 wt%, N-methyl-2-pyrrolidone: 30 wt%, γ-butyrolactone: 44 wt%, butyl cellosolve: 20 wt% A diluted solution was prepared. This solution was allowed to stand at 23 ° C. for 5 days.

(Synthesis Example 1)
After putting 174.9 g (672.0 mmol) of (X-1) into a 5000 mL four-necked flask containing a stirrer, 3153 g of N-methyl-2-pyrrolidone was added and stirred to dissolve. Next, 148.7 g (1470 mmol) of triethylamine and 161.2 g (700.0 mmol) of (Y-1) were added and dissolved by stirring.

  While stirring this solution, 563.5 g (1470 mmol) of DBOP was added, and 433.1 g of N-methyl-2-pyrrolidone was further added, followed by stirring at room temperature for 12 hours to obtain a polyamic acid ester solution. The viscosity of this polymic acid ester solution at a temperature of 25 ° C. was 61.1 mPa · s.

  This polymic acid ester solution was put into methanol {27800 g}, and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a polyamic acid ester powder. The molecular weight of this polyamic acid ester was Mn = 13,400 and Mw = 34,600.

(Synthesis Example 2)
After putting 86.6 g (333.0 mmol) of (X-1) into a 3000 mL four-necked flask containing a stir bar, 1644 g of N-methyl-2-pyrrolidone was added and dissolved by stirring. Next, 76.5 g (756. mmol) of triethylamine and 87.9 g (360.0 mmol) of (Y-2) were added and dissolved by stirring.

  While stirring this solution, 289.8 g (756 mmol) of DBOP was added, and 225.8 g of N-methyl-2-pyrrolidone was further added, followed by stirring at room temperature for 12 hours to obtain a polyamic acid ester solution. The viscosity of this polymic acid ester solution at a temperature of 25 ° C. was 65.3 mPa · s.

  This polymic acid ester solution was put into methanol {14500 g}, and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a polyamic acid ester powder. The molecular weight of this polyamic acid ester was Mn = 13,200 and Mw = 25,900.

(Synthesis Example 3)
12.2 g (47.0 mmol) of (X-1) was charged into a 500 mL four-necked flask containing a stirring bar, and then 232 g of N-methyl-2-pyrrolidone was added and dissolved by stirring. Subsequently, 10.2 g (100.8 mmol) of triethylamine and 12.4 g (48.0 mmol) of (Y-3) were added and dissolved by stirring.

  While stirring this solution, 38.6 g (100.8 mmol) of DBOP was added, and 31.9 g of N-methyl-2-pyrrolidone was further added, followed by stirring at room temperature for 12 hours to obtain a polyamic acid ester solution. The viscosity of this polymic acid ester solution at a temperature of 25 ° C. was 213.2 mPa · s.

  This polymic acid ester solution was put into methanol {2020 g}, and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a polyamic acid ester powder. The molecular weight of this polyamic acid ester was Mn = 24,700 and Mw = 59,300.

(Synthesis Example 4)
After putting 11.0 g (42.1 mmol) of (X-1) into a 500 mL four-necked flask containing a stir bar, 220 g of N-methyl-2-pyrrolidone was added and dissolved by stirring. Next, 9.14 g (90.3 mmol) of triethylamine and 12.3 g (43.0 mmol) of (Y-4) were added and dissolved by stirring.

  While stirring this solution, 34.6 g (90.3 mmol) of DBOP was added, 30.2 g of N-methyl-2-pyrrolidone was further added, and the mixture was stirred at room temperature for 12 hours to obtain a polyamic acid ester solution. The viscosity of this polymic acid ester solution at a temperature of 25 ° C. was 348.0 mPa · s.

  This polymic acid ester solution was put into methanol {1900 g}, and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a polyamic acid ester powder. The molecular weight of this polyamic acid ester was Mn = 26,800 and Mw = 66,500.

(Synthesis Example 5)
After putting 7.45 g (28.7 mmol) of (X-1) into a 500 mL four-necked flask containing a stir bar, 138 g of N-methyl-2-pyrrolidone was added and dissolved by stirring. Next, 6.38 g (63.0 mmol) of triethylamine, 5.87 g (25.5 mmol) of (Y-1), and 1.34 g (4.5 mmol) of (Y-5) were added and stirred to dissolve. It was.

  While stirring this solution, 24.2 g (63.0 mmol) of DBOP was added, and 18.9 g of N-methyl-2-pyrrolidone was further added, followed by stirring at room temperature for 12 hours to obtain a polyamic acid ester solution. The viscosity of this polymic acid ester solution at a temperature of 25 ° C. was 65.0 mPa · s.

  This polymic acid ester solution was put into methanol {1200 g}, and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a polyamic acid ester powder. The molecular weight of this polyamic acid ester was Mn = 14,200 and Mw = 35,300.

(Synthesis Example 6)
After putting 114.9 g (441.6 mmol) of (X-1) into a 5000 mL four-necked flask containing a stir bar, 2226 g of N-methyl-2-pyrrolidone was added and dissolved by stirring. Next, 102.0 g (1008.0 mmol) of triethylamine, 99.67 g (408.0 mmol) of (Y-2), and 21.48 g (72.0 mmol) of (Y-5) were added and stirred to dissolve. It was.

  While stirring this solution, 386.4 g (1008.0 mmol) of DBOP was added, 305.8 g of N-methyl-2-pyrrolidone was further added, and the mixture was stirred at room temperature for 12 hours to obtain a polyamic acid ester solution. The viscosity of this polymic acid ester solution at a temperature of 25 ° C. was 88.5 mPa · s.

  This polymic acid ester solution was put into methanol {19500 g}, and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a polyamic acid ester powder. The molecular weight of this polyamic acid ester was Mn = 16,400 and Mw = 33,200.

(Synthesis Example 7)
Take 8.52 g (37.0 mmol) of (Y-1) in a 100 mL four-necked flask containing a stir bar, add 112.0 g of N-methyl-2-pyrrolidone, and dissolve by stirring while feeding nitrogen. It was. While stirring this diamine solution, 6.89 g (35.2 mmol) of (X-2) was added, and further 27.7 g of N-methyl-2-pyrrolidone was added, followed by stirring at 23 ° C. for 5 hours under a nitrogen atmosphere. A polyamic acid solution was obtained. The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 436 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 18400 and Mw = 47000.

(Synthesis Example 8)
After putting 23.9 g (92.0 mmol) of (X-1) into a 1000 mL four-necked flask containing a stir bar, 448 g of N-methyl-2-pyrrolidone was added and dissolved by stirring. Subsequently, 21.2 g (210 mmol) of triethylamine, 11.51 g (50.0 mmol) of (Y-1), and 12.21 g (50.0 mmol) of (Y-2) were added and dissolved by stirring.

  While stirring this solution, 80.5 g (210 mmol) of DBOP was added, 61.6 g of N-methyl-2-pyrrolidone was further added, and the mixture was stirred at room temperature for 12 hours to obtain a polyamic acid ester solution. The viscosity of this polymic acid ester solution at a temperature of 25 ° C. was 35.2 mPa · s.

  This polymic acid ester solution was put into methanol {660 g}, and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a polyamic acid ester powder. The molecular weight of this polyamic acid ester was Mn = 10,100 and Mw = 19,200.

(Synthesis Example 9)
After putting 17.8 g (68.4 mmol) of (X-1) into a 1000 mL four-necked flask containing a stir bar, 345 g of N-methyl-2-pyrrolidone was added and dissolved by stirring. Next, 15.4 g (152 mmol) of triethylamine, 6.12 g (26.6 mmol) of (Y-1), 9.28 g (38.0 mmol) of (Y-2), and 3. (Y-5) of 3. 40 g (11.4 mmol) was added and dissolved by stirring.

  While stirring this solution, 58.3 g (152 mmol) of DBOP was added, 47.4 g of N-methyl-2-pyrrolidone was further added, and the mixture was stirred at room temperature for 12 hours to obtain a polyamic acid ester solution. The viscosity of this polymic acid ester solution at a temperature of 25 ° C. was 36.2 mPa · s.

  This polymic acid ester solution was put into methanol {3020 g}, and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a polyamic acid ester powder. The molecular weight of this polyamic acid ester was Mn = 8,600 and Mw = 18,900.

(Synthesis Example 10)
After putting 7.38 g (28.4 mmol) of (X-1) into a 500 mL four-necked flask containing a stirring bar, 140 g of N-methyl-2-pyrrolidone was added and stirred to dissolve. Next, 6.17 g (61.0 mmol) of triethylamine, 3.51 g (15.3 mmol) of (Y-1), 2.61 g (10.7 mmol) of (Y-2), and (Y-5) 1.37 g (4.58 mmol) was added and dissolved by stirring.

  While stirring this solution, 23.4 g (61.0 mmol) of DBOP was added, and 19.2 g of N-methyl-2-pyrrolidone was further added, followed by stirring at room temperature for 12 hours to obtain a polyamic acid ester solution. The viscosity of this polymic acid ester solution at a temperature of 25 ° C. was 43.4 mPa · s.

  This polymic acid ester solution was put into methanol {1220 g}, and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 100 ° C. to obtain a polyamic acid ester powder. The molecular weight of this polyamic acid ester was Mn = 10,200 and Mw = 23,700.

(Comparative Example 1)
1.77 g of the polyamic acid ester powder obtained in Synthesis Example 1 was placed in a 100 mL Erlenmeyer flask containing a stir bar, 27.7 g of N-methyl-2-pyrrolidone was added, and the mixture was dissolved by stirring at room temperature for 18 hours. Subsequently, 9.85 g of butyl cellosolve was added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content concentration of 4.34% by mass.

(Comparative Example 2)
3.87 g of the polyamic acid ester powder obtained in Synthesis Example 2 was placed in a 100 mL Erlenmeyer flask containing a stirring bar, 60.6 g of N-methyl-2-pyrrolidone was added, and the mixture was dissolved by stirring at room temperature for 18 hours. Subsequently, 21.5 g of butyl cellosolve was added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content concentration of 4.30% by mass.

(Comparative Example 3)
3.51 g of the polyamic acid ester powder obtained in Synthesis Example 3 was placed in a 100 mL Erlenmeyer flask containing a stirring bar, 55.0 g of N-methyl-2-pyrrolidone was added, and the mixture was dissolved by stirring at room temperature for 18 hours. Subsequently, 19.5 g of butyl cellosolve was added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content of 4.20% by mass.

(Comparative Example 4)
3.48 g of the polyamic acid ester powder obtained in Synthesis Example 4 was placed in a 100 mL Erlenmeyer flask containing a stirring bar, 54.5 g of N-methyl-2-pyrrolidone was added, and the mixture was dissolved by stirring at room temperature for 18 hours. Subsequently, 19.3 g of butyl cellosolve was added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content concentration of 4.20% by mass.

(Comparative Example 5)
3.94 g of the polyamic acid ester powder obtained in Synthesis Example 5 was placed in a 100 mL Erlenmeyer flask containing a stirring bar, 61.8 g of N-methyl-2-pyrrolidone was added, and the mixture was dissolved by stirring at room temperature for 18 hours. Subsequently, 21.9 g of butyl cellosolve was added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content of 4.28% by mass.

(Comparative Example 6)
3.25 g of the polyamic acid ester powder obtained in Synthesis Example 6 was placed in a 100 mL Erlenmeyer flask containing a stirring bar, 50.9 g of N-methyl-2-pyrrolidone was added, and the mixture was dissolved by stirring at room temperature for 18 hours. Subsequently, 18.1 g of butyl cellosolve was added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content concentration of 4.38% by mass.

(Comparative Example 7)
10.3 g of the polyamic acid solution obtained in Synthesis Example 7 was dispensed into a 100 mL Erlenmeyer flask containing a stirring bar, 18.7 g of N-methyl-2-pyrrolidone and 9.68 g of butyl cellosolve were added, and a magnetic stirrer was used for 2 hours. The mixture was stirred to obtain a polyamic acid solution having a solid content concentration of 4.00% by mass.

Example 1
4.10 g of the polyamic acid ester powder obtained in Synthesis Example 8 was placed in a 100 mL Erlenmeyer flask containing a stirring bar, 64.2 g of N-methyl-2-pyrrolidone was added, and the mixture was dissolved by stirring at room temperature for 18 hours. Subsequently, 22.8 g of butyl cellosolve was added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content of 4.40% by mass.

(Example 2)
3.81 g of the polyamic acid ester powder obtained in Synthesis Example 9 was placed in a 100 mL Erlenmeyer flask containing a stir bar, 59.7 g of N-methyl-2-pyrrolidone was added, and the mixture was dissolved by stirring at room temperature for 18 hours. Subsequently, 21.2 g of butyl cellosolve was added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content concentration of 4.41% by mass.

(Example 3)
4.21 g of the polyamic acid ester powder obtained in Synthesis Example 10 was placed in a 100 mL Erlenmeyer flask containing a stirring bar, 66.0 g of N-methyl-2-pyrrolidone was added, and the mixture was dissolved by stirring at room temperature for 18 hours. Subsequently, 23.4 g of butyl cellosolve was added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content concentration of 4.45% by mass.

Claims (8)

A diamine component containing a diamine of the following formulas (1) and (2) and a polyimide precursor obtained by a reaction with a tetracarboxylic acid derivative and at least one polymer selected from a polyimide obtained by imidizing the polyimide precursor Liquid crystal aligning agent to contain.

N in Formula (2) is an integer of 1, 3 or 5. The liquid crystal aligning agent of Claim 1 whose diamine of the said Formula (1) is 10-90 mol% in a diamine component. The liquid crystal aligning agent of Claim 1, 2 whose diamine of the said Formula (2) is 10-90 mol% in a diamine component. The liquid crystal aligning agent of any one of Claims 1-3 in which the said tetracarboxylic acid derivative contains an aliphatic structure or an alicyclic group structure in a structure. The tetracarboxylic acid derivative containing an aliphatic structure or an alicyclic group structure in the structure is 10 to 90 mol% in the total tetracarboxylic acid derivative, or any one of claims 1 to 4. Liquid crystal aligning agent. The liquid crystal aligning agent according to any one of claims 1 to 5, wherein the carboxylic acid derivative is a dicarboxylic acid diester. The liquid crystal aligning film obtained by apply | coating and baking the liquid crystal aligning agent of any one of Claims 1-6 on a board | substrate. The liquid crystal display element which has a liquid crystal aligning film of Claim 7.