WO2014010402A1

WO2014010402A1 - Liquid crystal alignment agent containing polyamic acid ester, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: WO2014010402A1
Application number: PCT/JP2013/067291
Authority: WO
Inventors: 秀則石井
Original assignee: 日産化学工業株式会社
Priority date: 2012-07-11
Filing date: 2013-06-24
Publication date: 2014-01-16
Also published as: KR20150032325A; CN104603683B; TW201407243A; JPWO2014010402A1; CN104603683A

Abstract

Provided is a liquid crystal alignment agent whereby the problems of printing properties and precipitation of contained polymers can be simultaneously overcome, and whereby a liquid crystal alignment film can be formed having minimal residual charge when a direct-current voltage is applied, rapid relaxation of residual charge, and high film permeation rate. A liquid crystal alignment agent characterized by containing an organic solvent and a polyamic acid ester having 30-100 mol% of structural units represented by formula (1) with respect to 1 mole of all structural units derived from a tetracarboxylic acid derivative, and 20-100 mol% of structural units represented by formula (2) with respect to 1 mole of all diamine-derived structural units. (In the formulae, X¹ is a tetravalent aromatic organic group, R¹ is an ethyl group, R² is a hydrogen atom or a C₁-C₅ alkyl group, hydrogen atoms and C₁-C₅ alkyl groups may be mixed, and A¹ and A² are each independently a hydrogen atom or a methyl group.)

Description

Liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element containing polyamic acid ester

The present invention relates to a liquid crystal aligning agent containing a polyamic acid ester and a liquid crystal aligning film obtained from the liquid crystal aligning agent.

Liquid crystal display elements used for liquid crystal televisions, liquid crystal displays, and the like are usually provided with a liquid crystal alignment film for controlling the alignment state of the liquid crystals. As a liquid crystal alignment film, a polyimide-based liquid crystal alignment film obtained by applying a liquid crystal alignment agent mainly composed of a polyimide precursor such as polyamic acid (polyamic acid) or a solution of soluble polyimide to a glass substrate or the like and baking it is used. Mainly used.

As liquid crystal display elements have become higher in definition, liquid crystal alignment films have high liquid crystal alignment characteristics and stable pretilt angles in addition to the demands for suppressing the decrease in contrast and reducing the afterimage phenomenon. Characteristics such as a voltage holding ratio, suppression of an afterimage generated by AC driving, a small residual charge when a DC voltage is applied, and / or an early relaxation of a residual charge accumulated by a DC voltage are becoming increasingly important.

Various proposals have been made for polyimide-based liquid crystal alignment films in order to meet the above requirements. For example, a liquid crystal alignment film containing a tertiary amine having a specific structure in addition to polyamic acid or an imide group-containing polyamic acid as a liquid crystal alignment film having a short time until an afterimage generated by a DC voltage disappears (for example, And Patent Document 1), and those using a liquid crystal aligning agent containing a soluble polyimide using a specific diamine compound having a pyridine skeleton as a raw material have been proposed (for example, see Patent Document 2).

Japanese Unexamined Patent Publication No. 9-316200 Japanese Unexamined Patent Publication No. 10-104633

A liquid crystal display element having a liquid crystal alignment film obtained from a liquid crystal aligning agent containing polyamic acid or polyimide as described above has a fast relaxation of residual charges accumulated by a DC voltage. However, it has been found that the liquid crystal alignment film has a low transmittance of the resulting film because the nitrogen atoms in the amino group, imino group, and nitrogen-containing heterocycle are oxidized by oxygen in the air.
On the other hand, by using the polyamic acid ester as the polyimide precursor, it has been clarified by the present inventors that the residual charge accumulated by the DC voltage is quickly relaxed and the membrane transmittance is increased.

That is, by using a liquid crystal aligning agent containing a polyamic acid ester having an amino group, an imino group, and a nitrogen-containing heterocyclic ring, a liquid crystal alignment film having a high film transmittance and a quick relaxation of residual charges accumulated by a DC voltage Is obtained.

However, among the liquid crystal alignment agents containing 4,4′-diaminodiphenylamine or a derivative thereof as a diamine and a polyamic acid ester using an aromatic tetracarboxylic derivative as a tetracarboxylic acid derivative, methyl ester of aromatic tetracarboxylic acid For those using the polymer, the solubility of the polymer is poor, and the precipitation of the polymer and clogging of the filter may become a problem.
Furthermore, in the case of using an ester of a long-chain alkyl group having 3 or more carbon atoms, printability is poor and a uniform polyimide film may not be obtained.

The present invention provides a liquid crystal alignment film in which a residual charge accumulated by a DC voltage is quickly relaxed and a liquid crystal alignment film having a high film transmittance can be obtained, and the problem of polymer precipitation and the problem of printability can be avoided at the same time. The purpose is to provide an agent.

In the polyamic acid ester using 4,4′-diaminodiphenylamine or a derivative thereof as a diamine and using an aromatic tetracarboxylic derivative as a tetracarboxylic acid derivative, the present inventors used ethyl ester as the aromatic tetracarboxylic acid ester. It has been found that the residual charge accumulated by the direct current voltage can be relaxed quickly and the membrane permeability can be increased, and the problem of polymer precipitation or filter clogging and the problem of printability can be avoided at the same time. .

Thus, the present invention is based on the above findings and has the following gist.
1. The structural unit represented by the following formula (1) is 30 to 100 mol% with respect to 1 mol of all structural units derived from the tetracarboxylic acid derivative, and the structural unit represented by the following formula (2) A liquid crystal aligning agent comprising a polyamic acid ester having 20 to 100 mol% and an organic solvent with respect to 1 mol of all structural units derived from diamine.

In the formula (1), X ¹ is a tetravalent aromatic group, and R ¹ is an ethyl group.

In the formula (2), R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and a hydrogen atom and an alkyl group having 1 to 5 carbon atoms may be mixed,
A ¹ and A ² are each independently a hydrogen atom or a methyl group.
2. Furthermore, the liquid crystal aligning agent of said 1 containing the solvent of lower surface tension than the said organic solvent.
3. X ¹ in Formula (1) is a benzene ring, the liquid crystal alignment agent according to Claim 1 or 2.
4). 4. The liquid crystal aligning agent according to any one of 1 to 3 above, wherein R ² in formula (2) is a hydrogen atom or a methyl group.
5. 5. The liquid crystal aligning agent according to any one of 1 to 4 above, wherein A ¹ and A ² in formula (2) are hydrogen atoms.
6). 6. The liquid crystal aligning agent according to any one of 1 to 5 above, wherein the polyamic acid ester has a weight average molecular weight of 5,000 to 300,000 and a number average molecular weight of 2,500 to 150,000.
7). 7. The liquid crystal aligning agent according to any one of 1 to 6 above, wherein the concentration of the polyamic acid ester in the liquid crystal aligning agent is 0.5 to 15% by mass.
8). 8. A liquid crystal alignment film obtained by applying and baking the liquid crystal aligning agent according to any one of 1 to 7 above.
9. 9. The liquid crystal alignment film as described in 8 above, wherein the film thickness after firing is from 5 to 300 nm.
10. 10. A liquid crystal display element comprising the liquid crystal alignment film as described in 8 or 9 above.

The liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention is based on a polyamic acid ester structure using 4,4′-diaminodiphenylamine or a derivative thereof as a diamine and an aromatic tetracarboxylic derivative as a tetracarboxylic acid derivative. The residual charge accumulated by the DC voltage of the liquid crystal display element having the liquid crystal alignment film is high.
Further, the liquid crystal aligning agent of the present invention employs ethyl ester as an ester, so that the solubility of the polymer is good, there is no problem such as precipitation or filter clogging, and the printing property to the substrate is good. . This is considered to be due to the fact that the alkyl ester portion of the aromatic tetracarboxylic acid derivative is an ethyl group, as described below.

It is generally known that the greater the alkyl carbon number of an alkyl ester, the higher the solubility in a solvent. On the other hand, it is known that when a polymer solution is applied to a substrate, the higher the hydrophobicity of the polymer, the more the polymer solution is repelled and cannot be uniformly applied. In other words, although methyl ester has good printability on the substrate, the solubility is insufficient, and long-chain alkyl esters having 3 or more carbon atoms have good solubility, but printability on the substrate is insufficient. It is. Therefore, it is considered that only ethyl ester can achieve both solubility and printability.

Thus, the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention has a high transmittance and can accelerate the relaxation of the residual charge accumulated by the DC voltage of the liquid crystal display element having the liquid crystal alignment film. Moreover, the liquid crystal aligning agent of this invention can eliminate simultaneously the problem of precipitation of a containing polymer, the clogging to a filter, and the problem of printability.

<Polyamic acid ester>
The polyamic acid ester used for the liquid crystal aligning agent of this invention is a polyimide precursor for obtaining a polyimide, and is a polymer which has the site | part which can perform the imidation reaction shown below by heating.

The polyamic acid ester has a structural unit derived from a tetracarboxylic acid derivative and a structural unit derived from a diamine, but the polyamic acid ester contained in the liquid crystal aligning agent of the present invention has a structural unit represented by the following formula (1). 30 to 100 mol% with respect to 1 mol of all structural units derived from a tetracarboxylic acid derivative, and a structural unit represented by the following formula (2) with respect to 1 mol of all structural units derived from diamine It is a polyamic acid ester having 20 to 100 mol%.

In the formula (2), R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and a hydrogen atom and an alkyl group having 1 to 5 carbon atoms may be mixed, and A ¹ and A ² are Each independently represents a hydrogen atom or a methyl group.

In the formula (1), X ¹ is a tetravalent aromatic group. The tetravalent aromatic group is a tetravalent aromatic group selected from a benzene ring and a naphthalene ring, or the two benzene rings are a single bond, oxygen atom, sulfur atom, nitrogen atom, carbonyl, sulfonyl, or A tetravalent aromatic group having a structure bonded through alkylene is preferable, and specific examples are as follows.

Among these, X-1 is preferable as X ¹ from the viewpoint of availability.
In the polyamic acid ester of the present invention, the structural unit of the formula (1) is preferably 30 to 100 mol%, more preferably 40 to 100 mol based on 1 mol of all structural units derived from the tetracarboxylic acid derivative. %, More preferably 50 to 100 mol%.

In formula (2), A ¹ and A ² are each independently a hydrogen atom or a methyl group. Of these, a hydrogen atom is preferable.

In the formula (2), specific examples of the alkyl group in R ² include methyl group, ethyl group, propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, and t-butyl. Group, n-pentyl group and the like.
R ² is preferably a hydrogen atom, an ethyl group or a methyl group, more preferably a hydrogen atom or a methyl group.

In the polyamic acid ester of the present invention, the structural unit of the formula (2) is preferably 20 to 100 mol%, more preferably 40 to 100 mol%, more preferably 1 mol relative to 1 mol of all structural units derived from diamine. Preferably, it is 60 to 100 mol%.

The polyamic acid ester used in the present invention may contain a structural unit represented by the following formula (3) as a structural unit derived from a tetracarboxylic acid derivative.

In the formula (3), R ³ is an alkyl group having 1 to 5 carbon atoms, and X is a tetravalent organic group.
Specific examples of X include the following X-101 to X-133. Among these, X is X-101, X-102, X-103, X-104, X-105, X-106, X-108, X-116, X-119, X- 121 or X-125 is preferred.

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

If the proportion of the structural unit represented by the formula (3) in the polyamic acid ester used in the present invention is increased, the effect of the present invention may be impaired, which is not preferable. Accordingly, the proportion of the structural unit represented by the formula (3) is preferably 0 to 70 mol%, more preferably 0 to 60 mol%, and still more preferably 0 to 0 mol per mol of the structural unit of the polyamic acid ester. 50 mol%.

The polyamic acid ester used in the present invention may contain a structural unit represented by the following formula (4) as a structural unit derived from diamine.

In the formula (4), A ³ and A ⁴ each independently represent a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, or an optionally substituted carbon atom having 1 to Or an alkynyl group having 1 to 10 carbon atoms which may have a substituent.
Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a t-butyl group, a hexyl group, an octyl group, a decyl group, a cyclopentyl group, a cyclohexyl group, and a bicyclohexyl group.
Examples of the alkenyl group include those in which one or more CH ₂ —CH ₂ structures present in the above alkyl group are replaced with a CH═CH structure, and more specifically, vinyl groups, allyl groups, 1- Examples include propenyl group, 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 -Propynyl group and the like.

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 such substituents are 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. Group, alkenyl group, alkynyl group and the like.

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.

As the substituent, the organooxy group can have a structure represented by —O—R. 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, a 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.

The organosilyl group as a substituent can have a structure represented by —Si— (R) ₃ . 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.

The acyl group as a substituent can have a structure represented by —C (O) —R. 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 the ester group which is a substituent, a 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 the thioester group which is a substituent, a structure represented by —C (S) OR— 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.

The phosphate group which is a substituent can have a structure represented by —OP (O) — (OR) ₂ . 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.

The amide group as a substituent includes —C (O) NH ₂ , —C (O) NHR, —NHC (O) R, —C (O) N (R) ₂ , or —NRC (O) R. The structure represented can be shown. When two Rs on the nitrogen atom are present, Rs may be the same or different, and examples of R include the above-described alkyl group, alkenyl group, alkynyl group, aryl group and the like. 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 ³ and A ⁴ , a hydrogen atom or a carbon atom that may have a substituent is 1 An alkyl group of 1 to 5 is more preferable, and a hydrogen atom, a methyl group or an ethyl group is particularly preferable.

Y is a divalent organic group, and the structure thereof is not particularly limited, and two or more types may be mixed. For example, the following Y-1 to Y-118 are given as specific examples.

Among them, in order to obtain good liquid crystal alignment, it is preferable to introduce a highly linear diamine into the polyamic acid ester, where Y is Y-7, Y-21, Y-22, Y-23, Y -25, Y-26, Y-27, Y-43, Y-44, Y-45, Y-46, Y-48, Y-63, Y-71, Y-73, Y-74, Y-75 Y-98, Y-99, and Y-100 are more preferable. In order to increase the pretilt angle, it is preferable to introduce a diamine having a long chain alkyl group, aromatic ring, aliphatic ring, steroid skeleton, or a combination thereof in the side chain into the polyamic acid ester. Y-76, Y-77, Y-78, Y-79, Y-80, Y-81, Y-82, Y-83, Y-84, Y-85, Y-86, Y-87 Y-88, Y-89, Y-90, Y-91, Y-92, Y-93, Y-94, Y-95, Y-96, and Y-97 are more preferable.
By adding 1 to 50 mol%, preferably 5 to 40 mol% of these diamines, any pretilt angle can be expressed.
When it is desired to improve rubbing resistance, Y is preferably a diamine having Y-118.

In the formula (Y-109), m and n are each independently an integer of 1 to 11, m + n is an integer of 2 to 12, and in the formula (Y-114), h is 1 to 3. In the formulas (Y-111) and (Y-117), j is an integer of 0 to 3.

If the proportion of the structural unit represented by the formula (4) in the polyamic acid ester used in the present invention is increased, the effect of the present invention may be impaired, which is not preferable. Therefore, the proportion of the structural unit represented by the formula (4) is preferably 0 to 80 mol%, more preferably 0 to 60 mol%, still more preferably 0 to 0 mol per mol of the structural unit of the polyamic acid ester. 40 mol%.
<Method for producing polyamic acid ester>

The polyamic acid ester can be synthesized by the following methods (1) to (3) using a tetracarboxylic acid derivative and a diamine compound.

(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 synthesis is carried out by reacting the polyamic acid and the esterifying agent in the presence of a solvent at −20 to 150 ° C., preferably 0 to 50 ° C., for 30 minutes to 24 hours, preferably 1 to 4 hours. Can do.

The esterifying agent is preferably one that can be easily removed by purification, 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 amount of the esterifying agent added is preferably 2 to 6 molar equivalents, more preferably 2.1 to 3 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, γ-butyrolactone or the like in view of polymer solubility. These may be used alone or in combination of two or more. Also 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 product is easily obtained.

(2) When synthesized by reaction of tetracarboxylic acid diester dichloride and diamine Polyamic acid ester can be synthesized from tetracarboxylic acid diester dichloride and diamine.
Specifically, tetracarboxylic acid diester dichloride and diamine are reacted in the presence of a base and a solvent at −20 to 150 ° C., preferably at 0 to 50 ° C., for 30 minutes to 24 hours, preferably for 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 times mol, preferably 2.1 to 3 times the amount of tetracarboxylic acid diester dichloride, from the viewpoint of easy removal and high molecular weight. Mole is more preferred.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in view of 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 is difficult to occur and a high molecular weight product is easily obtained.
In order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for the synthesis of the polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent mixing of outside air in a nitrogen atmosphere.

(3) When synthesizing polyamic acid ester from tetracarboxylic acid diester and diamine Polyamic acid ester can be synthesized by polycondensation of tetracarboxylic acid diester and diamine.
Specifically, tetracarboxylic acid diester and diamine are reacted in the presence of a condensing agent, base, solvent, etc. at 0 to 150 ° C., preferably 0 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-triazide. Nylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N , N ′, N′-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate diphenyl, and the like. The amount of the condensing agent added is preferably 2 to 3 moles, more preferably 2.1 to 2.5 moles relative to the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the base is preferably 0.1 to 4 times mol, more preferably 0.5 to 3 times mol with respect to the diamine component, from the viewpoint of easy removal and easy obtaining of a high molecular weight product.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in view of 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 is difficult to occur and a high molecular weight product is easily obtained.
In order to prevent hydrolysis of the condensing agent, the solvent used for the synthesis of the polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent external air from being mixed in a nitrogen atmosphere.

In addition, in the reactions (1) to (3) above, the reaction proceeds efficiently by adding a 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 mol with respect to the diamine component.

Among the methods for synthesizing the three polyamic acid esters, since the high molecular weight polyamic acid ester is obtained, the synthesis method (1) or (2) 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, washed with a poor solvent, and then dried at room temperature or by heating to obtain a purified polyamic acid ester powder.
The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve, acetone, and toluene. Of these, water, methanol, ethanol, or 2-propanol is preferable.
<Liquid crystal aligning agent>

The liquid crystal aligning agent of the present invention contains a polyamic acid ester having a structural unit represented by the above formula (1), a structural unit represented by the formula (2), and an organic solvent.

The weight average molecular weight of the polyamic acid ester having the structural unit represented by the formula (1) and the structural unit represented by the formula (2) is preferably 5,000 to 300,000, more preferably 10, 000-200,000. The number average molecular weight is preferably 2,500 to 150,000, and more preferably 5,000 to 10,000.

The liquid crystal aligning agent of the present invention is in the form of a solution in which the polyamic acid ester is dissolved in an organic solvent. As long as it has such a form, for example, when the polyamic acid ester is synthesized in an organic solvent, the resulting reaction solution itself may be used, or the reaction solution may be diluted with another solvent. Good. When the polyamic acid ester is obtained as a powder, it may be dissolved in an organic solvent to form a solution.

The content (concentration) of the polyamic acid ester (hereinafter also referred to as a polymer) in the liquid crystal aligning agent of the present invention can be changed as appropriate depending on the thickness of the polyimide film to be formed. The content of the polymer component is preferably 0.5% by mass or more with respect to the organic solvent from the viewpoint of forming a coating film free from water, and is preferably 15% by mass or less from the viewpoint of storage stability of the solution. Preferably, it is 1 to 10% by mass. In this case, a concentrated solution of the polymer may be prepared in advance, and diluted when such a concentrated solution is used as the liquid crystal alignment agent. The concentration of the concentrated solution of the polymer component is preferably 10 to 30% by mass, and more preferably 10 to 15% by mass.
Alternatively, the polymer component powder may be heated when dissolved in an organic solvent to prepare a solution. The heating temperature is preferably 20 to 150 ° C, particularly preferably 20 to 80 ° C.

The organic solvent contained in the liquid crystal aligning agent of the present invention is not particularly limited as long as the polymer component is uniformly dissolved. 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 component uniformly by itself, if it is a range which a polymer does not precipitate, you may mix with said organic solvent.

The liquid crystal aligning agent of this invention may contain 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 a polymer component. 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, butyl cellosolve acetate, 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, 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 kinds of solvents may be used in combination.
The amount of the low surface tension solvent used is preferably 1 to 50% by mass, more preferably 10 to 30% by mass, based on the total solvent (100% by mass) contained in the liquid crystal aligning agent. If it is 10 mass% or more, it is preferable at the point of the coating-film uniformity to the board | substrate of a liquid crystal aligning agent, and if it is 30 mass% or less, it is preferable from the point of the solubility of a polymer component.

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, polymers other than polyamic acid esters, and the purpose of changing electrical properties such as dielectric constant and conductivity of the liquid crystal aligning film A dielectric or conductive material, a silane coupling agent for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate, a crosslinkable compound for the purpose of increasing the hardness and density of the film when it is made into a liquid crystal alignment film, When firing the coating film, an imidization accelerator for the purpose of efficiently proceeding imidization of the polyamic acid may be added.
<Liquid crystal alignment film>

The liquid crystal alignment film of the present invention is a film obtained by applying the above liquid crystal aligning agent to a substrate, drying and baking. The substrate to 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 plastic substrate such as a polycarbonate substrate, or the like can be used. It is preferable to use a substrate on which an ITO electrode or the like for driving is formed from the viewpoint of simplification of the process. 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 be used as the electrode.

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 contained organic solvent, it is dried at 50 to 120 ° C. for 1 to 10 minutes, and then baked at 150 to 300 ° C. for 5 to 120 minutes. The thickness of the coating film after firing 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 methods 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, the surface of the coating film is irradiated with radiation deflected in a certain direction, and in some cases, a heat treatment is performed at a temperature of 150 to 250 ° C. to impart liquid crystal alignment ability. Is mentioned.
As the radiation, ultraviolet rays and visible rays having a wavelength of 100 to 800 nm can be used. Among these, ultraviolet rays having a wavelength of 100 to 400 nm are preferable, and those having a wavelength of 200 to 400 nm are particularly preferable. Further, in order to improve the liquid crystal orientation, radiation may be irradiated while heating the coated substrate at 50 to 250 ° C.
Dose of the radiation is preferably 1 ~ 10,000mJ / cm ^2, particularly preferably 100 ~ 5,000mJ / cm ^2.
The liquid crystal alignment film produced as described above can stably align liquid crystal molecules in a certain direction.
[Liquid crystal display element]

The liquid crystal display element of the present invention is a liquid crystal display element obtained by obtaining a substrate with a liquid crystal alignment film from the liquid crystal aligning agent of the present invention by the above-described method, performing an alignment treatment, and then preparing a liquid crystal cell by a known method. It is.

The manufacturing method of the liquid crystal cell is not particularly limited. For example, a pair of substrates on which the liquid crystal alignment film is formed is preferably 1 to 30 μm, more preferably 2 to 2 with the liquid crystal alignment film surface inside. A method is generally employed in which a 10 μm spacer 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.

The present invention will be described in more detail with reference to the following examples, but the present invention should not be construed as being limited thereto.
The abbreviations of the compounds used in the examples and comparative examples, and the measuring methods of the respective properties are as follows.
DBOP: Diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve

[viscosity]
As for the viscosity of the polyamic acid solution or the polyamic acid ester solution, an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) was used, the sample amount was 1.1 mL, the cone rotor TE-1 (1 ° 34 ′, R24), the temperature Measured at 25 ° C.

[Molecular weight]
The molecular weight of the polyamic acid ester is measured by a GPC (room temperature gel permeation chromatography) apparatus, and is a number average molecular weight (hereinafter also referred to as Mn) and a weight average molecular weight (hereinafter also referred to as Mw) as a polyethylene glycol or polyethylene oxide equivalent value. ) Was calculated.
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 (liter), phosphoric acid / anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) is 10 ml / L)
Flow rate: 1.0 ml / standard sample for preparing a calibration curve: TSK standard polyethylene oxide (weight average molecular weight (Mw) of about 900,000, 150,000, 100,000, and 30,000) manufactured by Tosoh Corporation, and polymer Polyethylene glycol (peak top molecular weight (Mp) of about 12,000, 4,000, and 1,000) manufactured by Laboratory Co., Ltd.
In order to avoid overlapping of peaks, the measurement was performed by mixing four types of 900,000, 100,000, 12,000, and 1,000, and 3 of 150,000, 30,000, and 4,000. Two samples of mixed samples were measured separately.

[Solid concentration measurement]
The solid content concentration of the polyamic acid ester solution was calculated as follows.
Aluminum cup with handle No. 2 (manufactured by ASONE), weighed approximately 1.1 g of the polyamic acid ester solution, heated in an oven DNF400 (manufactured by Yamato) at 200 ° C. for 2 hours, and then allowed to stand at room temperature for 5 minutes to leave the solid content in the aluminum cup. Was weighed. The solid content concentration was calculated from the solid content weight and the original solution weight value.

(Synthesis Example 1)
In a 200 mL four-necked flask containing a stir bar, weigh out 3.06 g (11.8 mmol) of DE-1 and 3.88 g (12.5 mmol) of DE-3, add 125 g of NMP, and dissolve by stirring. I let you. Subsequently, 5.32 g (52.5 mmol) of triethylamine, 1.99 g (10.0 mmol) of DA-1, 2.87 g (10.0 mmol) of DA-3, and 1.49 g (5 of DA-5) 0.0000 mmol) and dissolved by stirring. While stirring this solution, 20.1 g (52.5 mmol) of DBOP was added, 17.7 g of NMP was further added, and the mixture was stirred for 13 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 87.0 mPa · s.
The obtained polyamic acid ester solution was added to 1089 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 24700 and Mw = 54500.
3.31 g of the resulting polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 24.3 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 10.9% by mass. Subsequently, 2.89 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 20 hours. Further, 27.9 g of NMP and 24.5 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 3.5% by mass.

(Synthesis Example 2)
In a 200 mL four-necked flask containing a stir bar, weigh out 3.06 g (11.8 mmol) of DE-1 and 3.88 g (12.5 mmol) of DE-3, add 123 g of NMP, and dissolve by stirring. I let you. Subsequently, 5.31 g (52.5 mmol) of triethylamine, 1.99 g (10.0 mmol) of DA-1, 2.58 g (10.0 mmol) of DA-4, and 1.50 g (5 of DA-5) 0.0000 mmol) and dissolved by stirring. While stirring this solution, 20.1 g (52.5 mmol) of DBOP was added, 17.1 g of NMP was further added, and the mixture was stirred for 13 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 75.0 mPa · s.
The obtained polyamic acid ester solution was added to 1068 g of methanol with stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 24100 and Mw = 52200.
3.24 g of the resulting polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stir bar, 23.6 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 10.9% by mass. Subsequently, 2.79 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 20 hours. Further, 27.0 g of NMP and 23.8 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 3.5% by mass.

(Synthesis Example 3)
In a 200 mL four-necked flask containing a stirring bar, weigh out 3.06 g (11.8 mmol) of DE-1 and 3.88 g (12.5 mmol) of DE-3, add 120 g of NMP, and dissolve by stirring. I let you. Subsequently, 5.33 g (52.5 mmol) of triethylamine, 2.99 g (15.0 mmol) of DA-1, 1.30 g (5.00 mmol) of DA-4, and 1.49 g (5 of DA-5) 0.0000 mmol) and dissolved by stirring. While stirring this solution, 20.1 g (52.5 mmol) of DBOP was added, and 16.8 g of NMP was further added, followed by stirring for 13 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 85.4 mPa · s.
The obtained polyamic acid ester solution was added to 1045 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 23300 and Mw = 47500.
3.24 g of the resulting polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 23.8 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 11.1% by mass. Subsequently, 2.88 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 20 hours. Further, 28.1 g of NMP and 24.4 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 3.5% by mass.

(Synthesis Example 4)
In a 200 mL four-necked flask containing a stir bar, 1.57 g (6.00 mmol) of DE-1 and 5.43 g (17.5 mmol) of DE-3 were weighed and 120 g of NMP was added and dissolved by stirring. I let you. Subsequently, 5.32 g (52.5 mmol) of triethylamine, 0.99 g (5.00 mmol) of DA-1, 3.23 g (12.5 mmol) of DA-4, and 1.49 g (7 of DA-6) .50 mmol) was added and dissolved by stirring. While stirring this solution, 20.1 g (52.5 mmol) of DBOP was added, and 16.5 g of NMP was further added, followed by stirring for 16 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 26.4 mPa · s.
The obtained polyamic acid ester solution was added to 1047 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 14500 and Mw = 31500.
4.01 g of the obtained polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 29.4 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 10.9% by mass. Subsequently, 3.50 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 24 hours. Further, 5.20 g of NMP and 17.5 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 6.0% by mass.

(Synthesis Example 5)
In a 200 mL four-necked flask containing a stir bar, 1.56 g (6.00 mmol) of DE-1 and 5.43 g (17.5 mmol) of DE-3 were weighed and 124 g of NMP was added and dissolved by stirring. I let you. Subsequently, 5.31 g (52.5 mmol) of triethylamine, 0.99 g (5.00 mmol) of DA-1, 1.49 g (7.50 mmol) of DA-6, and 3.65 g of DA-8 (12 .50 mmol) was added and dissolved by stirring. While stirring this solution, 20.1 g (52.5 mmol) of DBOP was added, 55.5 g of NMP was further added, and the mixture was stirred for 18 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 8.6 mPa · s.
The obtained polyamic acid ester solution was added to 1079 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 10900 and Mw = 23800.
2.19 g of the obtained polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 16.1 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 10.3% by mass. Subsequently, 5.30 g of NMP and 9.57 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 5.5% by mass.

(Synthesis Example 6)
In a 500 mL four-necked flask containing a stir bar, 5.86 g (22.5 mmol) of DE-1 and 7.75 g (25.0 mmol) of DE-3 were weighed, and 240 g of NMP was added and dissolved by stirring. I let you. Subsequently, 10.6 g (105 mmol) of triethylamine, 2.99 g (15.0 mmol) of DA-1, 2.97 g (15.0 mmol) of DA-6, and 5.85 g (20.0 mmol) of DA-8 ) And stirred to dissolve. While stirring this solution, 40.3 g (105 mmol) of DBOP was added, 32.5 g of NMP was further added, and the mixture was stirred for 15 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 18.0 mPa · s.
The obtained polyamic acid ester solution was added to 2094 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 12000 and Mw = 25700.
2.18 g of the resulting polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 16.0 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of the polyamic acid ester solution was 11.2% by mass. Subsequently, 7.16 g of NMP and 10.3 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 5.5% by mass.

(Synthesis Example 7)
In a 500 mL four-necked flask containing a stir bar, 5.86 g (22.5 mmol) of DE-1 and 7.75 g (25.0 mmol) of DE-3 were weighed, and 240 g of NMP was added and dissolved by stirring. I let you. Subsequently, 10.6 g (105 mmol) of triethylamine, 3.00 g (15.0 mmol) of DA-1, 2.97 g (15.0 mmol) of DA-7, and 5.85 g (20.0 mmol) of DA-8. ) And stirred to dissolve. While stirring this solution, 40.3 g (105 mmol) of DBOP was added, 32.6 g of NMP was further added, and the mixture was stirred for 15 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 14.0 mPa · s.
The obtained polyamic acid ester solution was added to 2094 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 10000 and Mw = 21600.
2.19 g of the obtained polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 16.1 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 10.9% by mass. Subsequently, 6.60 g of NMP and 10.1 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid concentration of 5.5% by mass.

(Synthesis Example 8)
In a 300 mL four-necked flask containing a stir bar, weigh out 4.83 g (18.6 mmol) of DE-1 and 4.34 g (14.0 mmol) of DE-3, add 174 g of NMP, and dissolve by stirring. I let you. Subsequently, 7.42 g (73.5 mmol) of triethylamine, 1.39 g (7.00 mmol) of DA-1, 3.62 g (14.0 mmol) of DA-4, and 4.17 g (14 of DA-5) 0.0 mmol) and stirred to dissolve. While stirring this solution, 28.2 g (73.5 mmol) of DBOP was added, 23.8 g of NMP was further added, and the mixture was stirred for 16 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 31.5 mPa · s.
The obtained polyamic acid ester solution was added to 5032 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 10500 and Mw = 25500.
2.29 g of the obtained polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 26.4 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 7.4% by mass. Subsequently, 1.81 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 23 hours. Further, 1.92 g of NMP and 12.1 g of BCS were added, and the mixture was stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 4.5% by mass.

(Synthesis Example 9)
To a 200 mL four-necked flask containing a stirring bar, weigh out 3.38 g (13.0 mmol) of DE-1 and 3.10 g (10.0 mmol) of DE-3, add 121 g of NMP, and dissolve by stirring. I let you. Subsequently, 5.31 g (52.5 mmol) of triethylamine, 1.49 g (7.50 mmol) of DA-1, 2.59 g (10.0 mmol) of DA-4, and 2.24 g (7 of DA-5) .50 mmol) was added and dissolved by stirring. While stirring this solution, 20.1 g (52.5 mmol) of DBOP was added, 16.7 g of NMP was further added, and the mixture was stirred for 12 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 34.0 mPa · s.
The obtained polyamic acid ester solution was added to 2463 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 10300 and Mw = 26100.
3.19 g of the obtained polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 32.3 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 8.3% by mass. Subsequently, 2.83 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 24 hours. Further, 7.04 g of NMP and 18.9 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 4.5 mass%.

(Synthesis Example 10)
In a 200 mL four-necked flask containing a stirring bar, weigh 2.86 g (11.0 mmol) of DE-1 and 3.88 g (12.5 mmol) of DE-3, add 127 g of NMP, and dissolve by stirring. I let you. Subsequently, 5.01 g (49.4 mmol) of triethylamine, 1.50 g (7.50 mmol) of DA-1, 2.24 g (7.50 mmol) of DA-5, and 2.92 g (10 of 10) of DA-8. 0.0 mmol) and stirred to dissolve. While stirring this solution, 18.9 g (49.4 mmol) of DBOP was added, and 17.9 g of NMP was further added, followed by stirring for 16 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 18.8 mPa · s.
The obtained polyamic acid ester solution was poured into 1090 g of 2-propanol with stirring, and the deposited precipitate was separated by filtration. The precipitate was washed three times with 2-propanol 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 = 10400 and Mw = 21000.
4.97 g of the resulting polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 36.5 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 10.8% by mass. Subsequently, 4.30 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 20 hours. Further, 16.0 g of NMP and 25.8 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 5.0% by mass.

(Synthesis Example 11)
In a 200 mL four-necked flask containing a stirring bar, weigh 2.86 g (11.0 mmol) of DE-1 and 3.88 g (12.5 mmol) of DE-3, add 127 g of NMP, and dissolve by stirring. I let you. Subsequently, 5.00 g (49.4 mmol) of triethylamine, 1.50 g (7.50 mmol) of DA-1, 2.98 g (10.0 mmol) of DA-5, and 2.19 g (7 of DA-8) .50 mmol) was added and dissolved by stirring. While stirring this solution, 18.9 g (49.4 mmol) of DBOP was added, and 17.8 g of NMP was further added, followed by stirring for 16 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 20.4 mPa · s.
The obtained polyamic acid ester solution was poured into 1091 g of 2-propanol with stirring, and the deposited precipitate was separated by filtration. The precipitate was washed three times with 2-propanol 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 = 1100 and Mw = 2200.
5.01 g of the obtained polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 36.8 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 10.8% by mass. Subsequently, 4.33 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 20 hours. Furthermore, 16.1 g of NMP and 26.0 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 5.0% by mass.

(Synthesis Example 12)
In a 200 mL four-necked flask containing a stir bar, 2.15 g (8.25 mmol) of DE-1 and 4.65 g (15.0 mmol) of DE-3 were weighed and 128 g of NMP was added and dissolved by stirring. I let you. Subsequently, 4.94 g (48.8 mmol) of triethylamine, 1.50 g (7.50 mmol) of DA-1, 3.74 g (12.5 mmol) of DA-5, and 1.46 g (5 of DA-8) 0.0000 mmol) and dissolved by stirring. While stirring this solution, 18.7 g (48.8 mmol) of DBOP was added, and 17.9 g of NMP was further added, followed by stirring for 20 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 19.1 mPa · s.
The obtained polyamic acid ester solution was poured into 1096 g of 2-propanol with stirring, and the deposited precipitate was separated by filtration. The precipitate was washed three times with 2-propanol 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 = 8700 and Mw = 20000.
3.78 g of the resulting polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 27.7 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 10.7% by mass. Subsequently, 3.20 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 23 hours. Further, 4.26 g of NMP and 16.0 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 5.0% by mass.

(Synthesis Example 13)
To a 500 mL four-necked flask containing a stir bar, weigh out 9.84 g (37.8 mmol) of DE-1 and 8.69 g (28.0 mmol) of DE-3, add 352 g of NMP, and dissolve by stirring. I let you. Subsequently, 14.0 g (138 mmol) of triethylamine, 4.19 g (21.0 mmol) of DA-1, 8.35 g (28.0 mmol) of DA-5, and 6.14 g (21.0 mmol) of DA-8 ) And stirred to dissolve. While stirring this solution, 53.0 g (138 mmol) of DBOP was added, 48.2 g of NMP was further added, and the mixture was stirred for 14 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 22.6 mPa · s.
The obtained polyamic acid ester solution was poured into 3028 g of 2-propanol with stirring, and the deposited precipitate was separated by filtration. The precipitate was washed three times with 2-propanol 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 = 10600 and Mw = 20500.
11.7 g of the obtained polyamic acid ester powder was weighed into a 200 mL Erlenmeyer flask containing a stirring bar, 86.0 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 11.0% by mass. Subsequently, 10.6 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 21 hours. Further, 16.6 g of NMP and 52.8 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 6.0% by mass.

(Synthesis Example 14)
To a 500 mL four-necked flask containing a stir bar, weigh 11.7 g (44.8 mmol) of DE-1 and 6.52 g (21.0 mmol) of DE-3, add 349 g of NMP, and dissolve by stirring. I let you. Subsequently, 14.0 g (138 mmol) of triethylamine, 4.19 g (21.0 mmol) of DA-1, 8.35 g (28.0 mmol) of DA-5, and 6.14 g (21.0 mmol) of DA-8 ) And stirred to dissolve. While stirring this solution, 53.0 g (138 mmol) of DBOP was added, 47.9 g of NMP was further added, and the mixture was stirred for 16 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 26.2 mPa · s.
The obtained polyamic acid ester solution was added to 3002 g of 2-propanol with stirring, and the deposited precipitate was separated by filtration. The precipitate was washed three times with 2-propanol 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 = 10300 and Mw = 20600.
11.9 g of the obtained polyamic acid ester powder was weighed into a 200 mL Erlenmeyer flask containing a stirring bar, 87.8 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 11.0% by mass. Subsequently, 10.8 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 21 hours. Further, 17.3 g of NMP and 54.0 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 6.0% by mass.

(Synthesis Example 15)
In a 300 mL four-necked flask containing a stirring bar, weigh out 6.67 g (25.6 mmol) of DE-1 and 3.73 g (12.0 mmol) of DE-3, add 201 g of NMP, and dissolve by stirring. I let you. Subsequently, 8.00 g (79.0 mmol) of triethylamine, 2.57 g (12.0 mmol) of DA-2, 4.78 g (16.0 mmol) of DA-5, and 3.50 g (12 of 12) of DA-8 were obtained. 0.0 mmol) and stirred to dissolve. While stirring this solution, 30.3 g (79.0 mmol) of DBOP was added, 27.5 g of NMP was further added, and the mixture was stirred for 16 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 21.6 mPa · s.
The obtained polyamic acid ester solution was poured into 1728 g of 2-propanol with stirring, and the deposited precipitate was separated by filtration. The precipitate was washed three times with 2-propanol 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 = 9200 and Mw = 19600.
2.95 g of the obtained polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 21.7 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 11.0% by mass. Subsequently, 2.53 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 26 hours. Further, 9.90 g of NMP and 15.2 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 5.0% by mass.

(Comparative Synthesis Example 1)
In a 200 mL four-necked flask containing a stir bar, 1.56 g (6.00 mmol) of DE-1 and 4.94 g (17.5 mmol) of DE-2 were weighed and 115 g of NMP was added and dissolved by stirring. I let you. Subsequently, 5.32 g (52.5 mmol) of triethylamine, 1.00 g (5.00 mmol) of DA-1, 3.22 g (12.5 mmol) of DA-4, and 1.49 g (7 of DA-6) .50 mmol) was added and dissolved by stirring. While stirring this solution, 20.1 g (52.5 mmol) of DBOP was added, 15.8 g of NMP was further added, and the mixture was stirred for 16 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 24.0 mPa · s.
The obtained polyamic acid ester solution was added to 1010 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 11600 and Mw = 36200.
3.96 g of the obtained polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 29.1 g of NMP was added, and the mixture was stirred and dissolved at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 11.4% by mass. Subsequently, 3.64 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 24 hours, and precipitates were observed.

(Comparative Synthesis Example 2)
In a 200 mL four-necked flask containing a stir bar, 1.57 g (6.00 mmol) of DE-1 and 4.94 g (17.5 mmol) of DE-2 were weighed and 115 g of NMP was added and dissolved by stirring. I let you. Subsequently, 5.30 g (52.5 mmol) of triethylamine, 1.00 g (5.00 mmol) of DA-1, 3.22 g (12.5 mmol) of DA-4, and 1.49 g (7 of DA-7) .50 mmol) was added and dissolved by stirring. While stirring this solution, 20.1 g (52.5 mmol) of DBOP was added, 15.8 g of NMP was further added, and the mixture was stirred for 16 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 17.7 mPa · s.
The obtained polyamic acid ester solution was added to 1010 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 10300 and Mw = 26100.
The obtained polyamic acid ester powder (4.00 g) was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 29.4 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 11.3% by mass. Subsequently, 3.62 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 24 hours. Furthermore, 6.70 g of NMP and 18.2 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 6.0% by mass.

(Comparative Synthesis Example 3)
To a 500 mL four-necked flask containing a stirring bar, weigh out 8.59 g (33.0 mmol) of DE-1 and 6.77 g (24.0 mmol) of DE-2, add 270 g of NMP, and dissolve by stirring. I let you. Subsequently, 12.8 g (126 mmol) of triethylamine, 3.59 g (18.0 mmol) of DA-1, 6.20 g (24.0 mmol) of DA-4, and 3.57 g (18.0 mmol) of DA-6. ) And stirred to dissolve. While stirring this solution, 48.3 g (126 mmol) of DBOP was added, 37.0 g of NMP was further added, and the mixture was stirred for 18 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 35.8 mPa · s.
The obtained polyamic acid ester solution was poured into 2378 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 12400 and Mw = 26200.
21.9 g of the obtained polyamic acid ester powder was weighed into a 500 mL Erlenmeyer flask containing a stirring bar, 161 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 11.7% by mass. Subsequently, 21.3 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 24 hours. Further, 45.5 g of NMP and 106 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 6.0% by mass.

(Comparative Synthesis Example 4)
To a 500 mL four-necked flask containing a stirring bar, weigh out 8.59 g (33.0 mmol) of DE-1 and 6.77 g (24.0 mmol) of DE-2, add 270 g of NMP, and dissolve by stirring. I let you. Subsequently, 12.8 g (126 mmol) of triethylamine, 3.59 g (18.0 mmol) of DA-1, 6.20 g (24.0 mmol) of DA-4, and 3.57 g (18.0 mmol) of DA-7. ) And stirred to dissolve. While stirring this solution, 48.3 g (126 mmol) of DBOP was added, 37.0 g of NMP was further added, and the mixture was stirred for 18 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 25.5 mPa · s.
The obtained polyamic acid ester solution was poured into 2378 g of methanol while stirring, and the deposited precipitate was separated by filtration. This precipitate was washed with methanol three times 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 = 10900 and Mw = 23900.
21.7 g of the obtained polyamic acid ester powder was weighed into a 500 mL Erlenmeyer flask containing a stirring bar, 159 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 11.6% by mass. Subsequently, 21.0 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 24 hours. Further, 43.1 g of NMP and 104 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 6.0% by mass.

(Comparative Synthesis Example 5)
In a 100 mL four-necked flask containing a stir bar, 0.82 g (3.12 mmol) of DE-1 and 3.08 g (9.10 mmol) of DE-4 were weighed, and 67.1 g of NMP was added and stirred. And dissolved. Subsequently, 2.61 g (25.7 mmol) of triethylamine, 0.52 g (2.60 mmol) of DA-2, 0.77 g (3.90 mmol) of DA-6, and 1.90 g (6 of DA-8) .50 mmol) was added and dissolved by stirring. While stirring this solution, 9.84 g (25.7 mmol) of DBOP was added, and 9.42 g of NMP was further added, followed by stirring for 16 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 12.3 mPa · s.
The obtained polyamic acid ester solution was added to 575 g of 2-propanol with stirring, and the deposited precipitate was separated by filtration. The precipitate was washed three times with 2-propanol 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 = 7800 and Mw = 20000.
2.87 g of the resulting polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 21.1 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 10.6% by mass. Subsequently, 2.38 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 25 hours. Further, 8.42 g of NMP and 14.3 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 5.0% by mass.

(Comparative Synthesis Example 6)
In a 100 mL four-necked flask containing a stirring bar, 1.49 g (5.72 mmol) of DE-1 and 2.20 g (6.50 mmol) of DE-4 were weighed, and 68.5 g of NMP was added and stirred. And dissolved. Subsequently, 2.61 g (25.7 mmol) of triethylamine, 0.52 g (2.60 mmol) of DA-2, 1.49 g (5.20 mmol) of DA-3, and 1.53 g (5 of DA-8) 20 mmol) and stirred to dissolve. While stirring this solution, 9.83 g (25.7 mmol) of DBOP was added, and 9.53 g of NMP was further added, followed by stirring for 16 hours under water cooling to obtain a polyamic acid ester solution. The viscosity of this polyamic acid ester solution at a temperature of 25 ° C. was 24.3 mPa · s.
The obtained polyamic acid ester solution was poured into 585 g of 2-propanol with stirring, and the deposited precipitate was separated by filtration. The precipitate was washed three times with 2-propanol 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 = 9000 and Mw = 24500.
2.87 g of the obtained polyamic acid ester powder was weighed into a 100 mL Erlenmeyer flask containing a stirring bar, 21.0 g of NMP was added, and the mixture was dissolved by stirring at room temperature for 20 hours. The solid content concentration of this polyamic acid ester solution was 10.6% by mass. Subsequently, 2.39 g of a 1.0 mass% NMP solution of 3-glycidoxypropylmethyldiethoxysilane was added and stirred at a temperature of 50 ° C. for 25 hours. Further, 8.60 g of NMP and 14.3 g of BCS were added and stirred at room temperature for 6 hours to obtain a polyamic acid ester solution having a solid content concentration of 5.0% by mass.

(Example 1)
The polyamic acid ester solution obtained in Synthesis Example 1 was filtered through a 1.0 μm filter, and then applied to a glass substrate with an ITO electrode (manufactured by Minerva Electronics, width 380 × length 320 × thickness 1.1 (mm)). It was applied by spin coating and left at room temperature for 10 minutes while blowing with a fan. Subsequently, after drying for 5 minutes on a hot plate at a temperature of 50 ° C., the film was baked for 30 minutes in an IR (far infrared heating) furnace at a temperature of 230 ° C. to obtain a transparent and uniform polyimide film having a thickness of 100 nm.

(Example 2)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 2 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

(Example 3)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 3 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

Example 4
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 4 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

(Example 5)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 5 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

(Example 6)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 6 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

(Example 7)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 7 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

(Example 8)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 8 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

Example 9
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 9 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

(Example 10)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 10 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

(Example 11)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 11 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

Example 12
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 12 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

(Example 13)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 13 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

(Example 14)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 14 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

(Example 15)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Synthesis Example 15 was used to obtain a transparent and uniform polyimide film having a film thickness of 100 nm.

(Comparative Example 1)
When the polyamic acid ester solution obtained in Comparative Synthesis Example 2 was filtered with a 1.0 μm filter, it did not pass through the filter.

(Comparative Example 2)
When the polyamic acid ester solution obtained in Comparative Synthesis Example 3 was filtered with a 1.0 μm filter, filter clogging was observed.

(Comparative Example 3)
When the polyamic acid ester solution obtained in Comparative Synthesis Example 4 was filtered with a 1.0 μm filter, filter clogging was observed.

(Comparative Example 4)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Comparative Synthesis Example 5 was used, but a turbid and non-uniform polyimide film was obtained.

(Comparative Example 5)
The treatment was performed in the same manner as in Example 1 except that the polyamic acid ester solution obtained in Comparative Synthesis Example 6 was used, but a turbid and non-uniform polyimide film was obtained.

Table 1 summarizes the results of the synthesis examples, comparative synthesis examples, examples, and comparative examples.

As shown in Table 1, all of the liquid crystal aligning agents of Examples 1 to 15 exhibited good solubility and printability. On the other hand, Comparative Examples 1 to 3 were all poorly soluble and could not be printed.
Moreover, although the liquid crystal aligning agent of the comparative examples 4 and 5 had favorable solubility, printing property was bad and the polyimide film with uniformity was not obtained.

By using the liquid crystal aligning agent of the present invention, it has characteristics such as a small residual charge when a DC voltage is applied and / or a rapid relaxation of the residual charge accumulated by the DC voltage, and the obtained film has a high transmittance. A liquid crystal alignment film is obtained. As a result, the obtained liquid crystal alignment film is widely useful for a TN element, an STN element, a TFT liquid crystal element, and a vertical alignment type liquid crystal display element.
The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2012-155676 filed on July 11, 2012 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims

The structural unit represented by the following formula (1) is 30 to 100 mol% with respect to 1 mol of all structural units derived from the tetracarboxylic acid derivative, and the structural unit represented by the following formula (2) A liquid crystal aligning agent comprising a polyamic acid ester having 20 to 100 mol% and an organic solvent with respect to 1 mol of all structural units derived from diamine.

(In Formula (1), X 1 is a tetravalent organic group aromatic group, and R 1 is an ethyl group.)

(In Formula (2), R 2 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and a hydrogen atom and an alkyl group having 1 to 5 carbon atoms may be mixed,
A 1 and A 2 are each independently a hydrogen atom or a methyl group. )
Furthermore, the liquid crystal aligning agent of Claim 1 containing the solvent of lower surface tension than the said organic solvent.
The liquid crystal aligning agent according to claim 1 or 2 X 1 is a benzene ring in the formula (1).
The liquid crystal aligning agent according to any one of claims 1 to 3, wherein R 2 in the formula (2) is a hydrogen atom or a methyl group.
The liquid crystal aligning agent according to any one of claims 1 to 4, wherein A 1 and A 2 in the formula (2) are hydrogen atoms.
The liquid crystal aligning agent according to any one of claims 1 to 5, wherein the polyamic acid ester has a weight average molecular weight of 5,000 to 300,000 and a number average molecular weight of 2,500 to 150,000.
The liquid crystal aligning agent according to any one of claims 1 to 6, wherein the concentration of the polyamic acid ester in the liquid crystal aligning agent is 0.5 to 15% by mass.
A liquid crystal alignment film obtained by applying and baking the liquid crystal aligning agent according to any one of claims 1 to 7.
The liquid crystal alignment film according to claim 8, wherein the film thickness after firing is 5 to 300 nm.
A liquid crystal display element comprising the liquid crystal alignment film according to claim 8.