Diamines

Abstract

The present invention relates to a diamine having a structure represented by formula (1): # imgabs0 # formula (1) in which A represents an alkyl group having 1-3 carbon atoms, a benzyl group, a p-methoxybenzyl group, an acetyl group, a benzoyl group, a tert-butoxycarbonyl group, a 9-fluorenylmethoxycarbonyl group, or an R1R2R3Si group, and R1, R2, and R3 each independently represent an alkyl group having 1-3 carbon atoms or a phenyl group.

Description

[0001] This application is a divisional application of the following application:

[0002] Title of the Invention: Liquid Crystal Alignment Agent, Liquid Crystal Alignment Film, Liquid Crystal Display Element, and Diamine

[0003] International Filing Date: March 11, 2020

[0004] International Application Number: PCT / JP2020 / 010462

[0005] National Application Number: 202080026107.7 Technical Field

[0006] The present invention relates to a polymer for a liquid crystal display element, a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal display element, and a novel diamine for them. Background Art

[0007] In liquid crystal display elements, various driving methods have been developed, which differ in electrode structure, physical properties of liquid crystal molecules used, manufacturing processes, etc. For example, TN (twisted nematic) type, STN (super-twisted nematic) type, VA (vertical alignment) type, MVA (multi-domain vertical alignment) type, IPS (in-plane switching) type, FFS (fringe field switching) type, PSA (polymer-sustained alignment) type and other liquid crystal display elements are known.

[0008] These liquid crystal display elements are provided with a liquid crystal alignment film in order to align liquid crystal molecules. From the viewpoint of good various properties such as heat resistance, mechanical strength, and affinity with liquid crystal, a coating film formed of a polymer such as polyamic acid, polyimide, or polysiloxane is usually used as the material of the liquid crystal alignment film.

[0009] In recent years, there has been an increasing demand for higher image quality of liquid crystal display elements. In particular, in medical equipment displays and liquid crystal TVs, the so-called "image retention", that is, residual images during long-term driving, has become a major problem, and there is a high demand for reducing image retention. From the viewpoint of further improving the quality of liquid crystal display elements, it is desirable to obtain a liquid crystal display element that is less likely to generate image retention than in the past.

[0010] In view of such a situation, there are known a liquid crystal alignment film and a liquid crystal aligning agent that provide excellent reduction of afterimages (for example, refer to Patent Document 1, Patent Document 2, and Patent Document 3).

[0011] In addition, for the liquid crystal display element in the above use, characteristics that can withstand long-term use in a harsh use environment are also required. In Patent Document 4, it is disclosed that a liquid crystal aligning agent containing a specific compound can obtain a liquid crystal alignment film with less reduction in voltage holding ratio even after being exposed to backlight for a long time, and a highly reliable liquid crystal display element can be obtained.

[0012] Prior Art Documents

[0013] Patent Documents

[0014] Patent Document 1: Pamphlet of International Publication No. 2016 / 063834

[0015] Patent Document 2: Pamphlet of International Publication No. 2015 / 060366

[0016] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2018 - 054761

[0017] Patent Document 4: Pamphlet of International Publication No. 2010 / 074269 Summary of the Invention

[0018] Problems to be Solved by the Invention

[0019] Moreover, touch panel type liquid crystal display elements have become widely popular, and thus users frequently apply strong pressing force to such display elements with their fingers. At this time, spacers existing inside the liquid crystal display element move within the liquid crystal display element and scrape the liquid crystal alignment film. This causes the following technical problem: the liquid crystal alignment film to which pressure is applied by the spacers cannot restrict the alignment of liquid crystals, and even if the liquid crystal display element performs black display, light leaks from the peripheral portion of the spacers, resulting in bright spots being displayed.

[0020] The configurations of conventionally proposed liquid crystal aligning agents do not necessarily solve all of the above problems. The present invention has been completed based on the above situation, and its object is to provide a liquid crystal display element with less generation of afterimages, which can minimize bright spots even when physical friction such as scraping caused by spacers occurs, and has high reliability. In addition, a liquid crystal alignment film with high film strength and a liquid crystal aligning agent suitable for such a liquid crystal display element are provided.

[0021] In addition, in order to increase the effective pixel area in recent liquid crystal display elements, it is required not to form pixels in the peripheral outer edge portion on the substrate, so that the so-called border area becomes smaller and smaller. Along with the narrow bezel of the panel, when manufacturing a liquid crystal display element by bonding two substrates, the sealant used is coated on the polyimide-based liquid crystal alignment film, but there are the following problems: Since there are no polar groups on the polyimide, a covalent bond cannot be formed with the sealant on the surface of the liquid crystal alignment film, and the bonding between the substrates is insufficient. Therefore, it has become a problem to improve the adhesiveness (sealability) between the polyimide-based liquid crystal alignment film, the sealant, and the substrate.

[0022] Solutions to solve the problems

[0023] The inventors of the present invention have conducted in-depth research to solve the above problems, and as a result, it has been found that by introducing a specific structure into the polymer contained in the liquid crystal aligning agent and improving various properties at the same time, the present invention has been completed. Based on the above findings, the present invention has the following main points.

[0024] 1. A liquid crystal aligning agent containing a polymer obtained from a diamine having a structure represented by the following formula (1).

[0025]

[0026] In formula (1), A represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a benzyl group, a p-methoxybenzyl group, an alkoxy group having 1 to 3 carbon atoms, an acetyl group, a benzoyl group, a tert-butoxycarbonyl group, a 9-fluorenylmethoxycarbonyl group, or R 1 R 2 R 3 Si group, R 1 、R 2 and R 3 each independently represents an alkyl group having 1 to 3 carbon atoms or a phenyl group.

[0027] Advantages of the invention

[0028] According to the liquid crystal aligning agent of the present invention, a liquid crystal display element with less occurrence of afterimages and minimized bright spots even when physical friction such as scratching caused by spacers occurs, and a liquid crystal alignment film providing such an effect can be obtained.

[0029] According to the liquid crystal aligning agent of the present invention, a liquid crystal alignment film having excellent sealability with the sealant can be obtained. By using this liquid crystal alignment film, a liquid crystal display element having excellent sealability between substrates and strong impact resistance can be obtained. Regarding the mechanism of improving the sealability with the sealant, it is not necessarily clear, but it is considered as follows: The hydroxyl group, methoxy group or hydroxyl group generated by removing the protecting group by heating in the specific diamine is exposed on the surface of the liquid crystal alignment film, and the sealability between the liquid crystal alignment film and the sealant is improved by the interaction between the group and the functional group in the sealant. Detailed implementation mode

[0030] The liquid crystal aligning agent of the present invention is a liquid crystal aligning agent containing a polymer obtained from a diamine having the structure shown in the above formula (1) (hereinafter, also referred to as a specific polymer). Hereinafter, each condition will be described in detail.

[0031] <Diamine having a specific structure>

[0032] The polymer of the present invention is a polymer obtained from a diamine having the structure of the above formula (1).

[0033] Specific examples of the diamine of the above formula (1) are shown below, but are not limited thereto. Among them, from the viewpoint of alleviating the accumulation of electric charges, (1-1), (1-2), and (1-3) are particularly preferred.

[0034]

[0035] <Polymer>

[0036] The polymer of the present invention is a polymer obtained by using the above diamine. As specific examples, polyamic acid, polyamic acid ester, polyimide, polyurea, polyamide, etc. can be mentioned. However, from the viewpoint of being used as a liquid crystal aligning agent, it is more preferably at least one selected from a polyimide precursor containing a structural unit represented by the following formula (6) and a polyimide which is an imidized product of the polyimide precursor.

[0037]

[0038] In the above formula (6), X 1 is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y 1 is a divalent organic group derived from a diamine containing the structure of formula (1), and R 4 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. From the aspect of the ease of imidization based on heating, R 4 is preferably a hydrogen atom, methyl or ethyl.

[0039] <<Tetracarboxylic dianhydride>>

[0040] X 1 is a tetravalent organic group derived from a tetracarboxylic acid derivative, and its structure is not particularly limited. In addition, X 1 in the polyimide precursor can be appropriately selected according to the solubility of the polymer in the solvent, the coating property of the liquid crystal aligning agent, the alignment property of the liquid crystal when forming a liquid crystal alignment film, the voltage holding ratio, the accumulation of electric charges, and other required characteristics. It can be one kind in the same polymer or two or more kinds can be mixed.

[0041] If X is shown1 As specific examples, structures of formulas (X-1) to (X-46) described in claims 13 to 14 of International Publication Gazette 2015 / 119168 can be cited, etc.

[0042] The following shows preferred X 1 The structure is shown, but the present invention is not limited thereto.

[0043]

[0044] In the above structures, from the viewpoints of photo-orientability and the like, (A-1) and (A-2) are particularly preferred. From the viewpoints of further increasing the relaxation rate of accumulated charges and the like, (A-4) is particularly preferred. From the viewpoints of liquid crystal orientability and further increasing the relaxation rate of accumulated charges and the like, (A-15) to (A-17) are particularly preferred, etc.

[0045] <<Polymer (other structural units)>>

[0046] The polyimide precursor containing the structural unit represented by formula (6) may also contain at least one selected from the structural unit represented by the following formula (7) and the polyimide which is its imidized product within the range not impairing the effects of the present invention.

[0047]

[0048] In formula (7), X 2 is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y 2 is a divalent organic group derived from a diamine not containing the structure of formula (1) in the main chain direction, R 5 has the same definition as R in the above formula (6) 4 , and R 6 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. In addition, at least one of the two Rs 6 is preferably a hydrogen atom.

[0049] As specific examples of X 2 , structures the same as those exemplified for X in formula (6) which also includes preferred examples can be cited. In addition, Y in the polyimide precursor 1 is a divalent organic group derived from a diamine not containing the structure of formula (1) in the main chain direction, and its structure is not particularly limited. In addition, Y 2 can be appropriately selected according to the required characteristics such as the solubility of the polymer in a solvent, the coatability of the liquid crystal aligning agent, the liquid crystal orientability when forming a liquid crystal alignment film, the voltage holding ratio, and the accumulated charge. It can be one kind in the same polymer or two or more kinds can be mixed. 2 If Y is shown

[0050] If Y is shown2 Specific examples include: the structure of formula (2) described in claim 4 of International Publication Gazette 2015 / 119168, and the structures of formulas (Y-1) to (Y-97), (Y-101) to (Y-118) described in claims 8 to 12; a divalent organic group obtained by removing two amino groups from the formula (2) described in claim 6 of International Publication Gazette 2013 / 008906; a divalent organic group obtained by removing two amino groups from the formula (1) described in claim 8 of International Publication Gazette 2015 / 122413; the structure of formula (3) described in claim 8 of International Publication Gazette 2015 / 060360; a divalent organic group obtained by removing two amino groups from the formula (1) described in claim 8 of Japanese Patent Publication Gazette 2012-173514; a divalent organic group obtained by removing two amino groups from formulas (A) to (F) described in claim 9 of International Publication Gazette 2010-050523, etc.

[0051] The following shows preferred Y 2 structures, but the present invention is not limited thereto.

[0052]

[0053]

[0054] Among the above structures, from the viewpoint of further improving the film strength, etc., (B-28), (B-29), etc. are particularly preferred; from the viewpoint of further improving the liquid crystal alignment, etc., (B-1) to (B-3), etc. are particularly preferred; from the viewpoint of further improving the relaxation rate of the accumulated charge, etc., (B-14) to (B-18) and (B-27), etc. are particularly preferred; from the viewpoint of further improving the voltage holding ratio, etc., (B-26), etc. are preferred.

[0055] When the polyimide precursor containing the structural unit represented by formula (6) also contains the structural unit represented by formula (7), the structural unit represented by formula (6) is preferably 10 mol% or more, more preferably 15 mol% or more, and particularly preferably 20 mol% or more, based on the total of formula (6) and formula (7).

[0056] The molecular weight of the polyimide precursor used in the present invention is preferably 2,000 to 500,000 in terms of weight average molecular weight, more preferably 5,000 to 300,000, and further preferably 10,000 to 100,000.

[0057] As the polyimide having a divalent group represented by formula (1) in the main chain, a polyimide obtained by cyclizing the above polyimide precursor can be cited. In this polyimide, the cyclization rate (also referred to as the imidization rate) of the amide acid group does not necessarily need to be 100%, and can be arbitrarily adjusted according to the use and purpose.

[0058] As a method for imidizing a polyimide precursor, examples thereof include: thermal imidization by directly heating a solution of the polyimide precursor, or catalyst imidization by adding a catalyst to a solution of the polyimide precursor.

[0059] The liquid crystal aligning agent of the present invention is a composition containing the above-mentioned specific polymer and an organic solvent, and may also contain two or more specific polymers having different structures. In addition, as long as the effects described in the present invention are exhibited, the liquid crystal aligning agent of the present invention may also contain a polymer other than the specific polymer (hereinafter, also referred to as a second polymer) and various additives.

[0060] When the liquid crystal aligning agent of the present invention contains a second polymer, the proportion of the specific polymer relative to all polymer components is preferably 5% by mass or more, and an example thereof is 5 to 95% by mass.

[0061] Examples of the second polymer include polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or its derivative, poly(styrene-phenylmaleimide) derivative, poly(meth)acrylate, etc.

[0062] In particular, polyamic acid (hereinafter, also referred to as second polyamic acid) obtained from a tetracarboxylic dianhydride component and a diamine component is preferred as the second polymer.

[0063] As the tetracarboxylic dianhydride component for obtaining the second polyamic acid, the compound represented by the following formula (11) can be cited. The acid dianhydride component may be a substance composed of one compound or a substance composed of two or more compounds.

[0064]

[0065] In formula (11), A is a tetravalent organic group, preferably a tetravalent organic group having 4 to 30 carbon atoms.

[0066] Specific examples of A include structures identical to the structures exemplified for X in formula (6), including preferred examples. 1 including the same structures as those exemplified.

[0067] As the diamine component for obtaining the second polyamic acid, it can be appropriately determined according to the purpose. For example, the diamine represented by the following formula (12) can be used.

[0068]

[0069] (Y 9 represents a divalent organic group. A 9Each independently is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms, and they may be the same or different. From the viewpoint of liquid crystal alignment property, A 9 is preferably a hydrogen atom or a methyl group.)

[0070] Hereinafter, the structure of Y of the formula (12) preferably used as the diamine component for obtaining the second polyamic acid is shown, but the present invention is not limited thereto. 9

[0071]

[0072] For the purpose of improving electrical properties and relaxation properties, Y 9 is preferably a divalent organic group having a secondary or tertiary nitrogen atom, or a divalent organic group having -NH-CO-NH- in the molecule. In Y 9 ​In the case of a divalent organic group having a secondary or tertiary nitrogen atom, as specific examples of the formula (12), the following can be cited: a diamine having a pyrrole structure described in International Publication Gazette WO2017 / 126627, preferably a diamine having a structure represented by the following formula (pr); a diamine having a pyrrole structure described in International Publication Gazette WO2018 / 062197, preferably a diamine having a structure represented by the following formula (pn); a diamine having a carbazole structure described in International Publication Gazette WO2018 / 110354, preferably a diamine having a structure represented by the following formula (cz); a diamine having a nitrogen-containing heterocycle described in paragraphs

[0173] to

[0188] of International Publication Gazette WO2015 / 046374, a diamine having a nitrogen-containing structure described in paragraph

[0050] of Japanese Patent Application Laid-Open No. 2016-218149, a diamine represented by the following formula (BP); 2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino-2,4-dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis(3-aminopropyl)piperazine, 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]diphenylamine, 2,4-diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl-1,3,5-triazine, 2,4-diamino-1,3,5-triazine, 4,6-diamino-2-vinyl-1,3,5-triazine, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6-phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis(4-aminophenyl)-N-phenylamine, 4,4'-diaminodiphenyl-N-methylamine, 4,4'-diaminodiphenylamine, 3,6-diaminocarbazole, 9-methyl-3,6-diaminocarbazole, 9-ethyl-3,6-diaminocarbazole, diamines represented by the following formulas (w1) to (w2), etc.

[0073]

[0074] (R 1 represents a hydrogen atom, a fluorine atom, a cyano group, a hydroxyl group, a methyl group, R 2 each independently represents a single bond or a group "*1-R 3 -Ph-*2", R 3 represents a group selected from a single bond, -O-, -COO-, -OCO-, -(CH 2 ) l -, -O(CH 2) m A divalent organic group among O-, -CONH-, and -NHCO- (l and m represent integers from 1 to 5), *1 represents the bonding site to the benzene ring in formula (pr), and *2 represents the bonding site to the amino group in formula (pr). Ph represents a phenylene group. n represents 1 to 3.)

[0075]

[0076] (R 1 and R 2 each independently represent a hydrogen atom or a methyl group, R 3 represents a single bond or the group “*1-R 4 -Ph-*2”, R 4 represents a group selected from a single bond, -O-, -COO-, -OCO-, -(CH 2 ) l -, -O(CH 2 ) m O-, -CONH-, and -NHCO- (l and m represent integers from 1 to 5), *1 represents the bonding site to the benzene ring in formula (pn), and *2 represents the bonding site to the amino group in formula (pn). Ph represents a phenylene group. n represents 1 to 3.)

[0077]

[0078] (R 1 represents a hydrogen atom or a methyl group, R 2 represents a methyl group.)

[0079]

[0080] (X is a biphenyl skeleton or a fluorene ring, Y is a group selected from a benzene ring, a biphenyl skeleton, or -Ph-Z-Ph- (Ph represents a phenylene group), and Z is a divalent group represented by -O-, -NH-, -CH 2 -, -SO 2 -, -C(CH 3 ) 2 - or -C(CF 3 ) 2 -. A and B are hydrogen atoms or methyl groups.)

[0081]

[0082] (Sp represents a phenylene group, pyrrolidine, piperidine, piperazine, a divalent linear hydrocarbon group with 2 to 20 carbon atoms, or -CH 2- a group substituted by a group selected from -O-, -CO-, -CO-O-, -NRCO- (wherein R represents a hydrogen atom or a methyl group), -NRCOO- (wherein R represents a hydrogen atom or a methyl group), -CONR- (wherein R represents a hydrogen atom or a methyl group), -COS-, -NR- (wherein R represents a methyl group), pyrrolidine, piperidine, and piperazine).

[0083] In Y 9 When Y is a divalent organic group having -NH-CO-NH- in the molecule, as a specific example of the above formula (12), diamines in the following cases can be cited: In the following formula (4), A 1 is -NH-CO-NH-, or a -CH of an alkylene group having 2 to 20 carbon atoms 2 in which at least one of - is substituted by -NH-CO-NH-, or a -CH in an alkylene group having 2 to 20 carbon atoms 2 in which at least one of - is substituted by -NH-CO-NH- and at least one of the other -CH 2 - is substituted by a group selected from -O-, -CO-, -CO-O-, -NRCO- (wherein R represents a hydrogen atom or a methyl group), -NRCOO- (wherein R represents a hydrogen atom or a methyl group), -CONR- (wherein R represents a hydrogen atom or a methyl group), -COS-, -NR- (wherein R represents a methyl group). As specific examples of more preferable diamines, diamines represented by the following formulas (U-1) to (U-9) can be cited, etc.

[0084]

[0085] (A 1 represents a single bond, -NH-CO-NH-, or an alkylene group having 2 to 20 carbon atoms (wherein any -CH of the alkylene group 2 - is optionally substituted by -O-, -CO-, -CO-O-, -NRCO- (wherein R represents a hydrogen atom or a methyl group), -NRCOO- (wherein R represents a hydrogen atom or a methyl group), -CONR- (wherein R represents a hydrogen atom or a methyl group), -COS-, -NR- (wherein R represents a methyl group) or -NH-CO-NH-). A 2 represents a halogen atom, a hydroxyl group, or an alkyl or alkoxy group having 1 to 5 carbon atoms (wherein any hydrogen atom of the alkyl or alkoxy group is optionally substituted by a halogen atom). a is an integer of 0 to 4, and when a is 2 or more, A 2 may be the same or different. b and c are each independently an integer of 1 to 2).

[0086]

[0087] As preferable specific examples of the diamine represented by the above formulas (w1) to (w2), diamines represented by the following formulas (n3-1) to (n3-7), diamines represented by the following formulas (n4-1) to (n4-6), etc. can be exemplified.

[0088]

[0089] For the purpose of improving printability, a diamine compound having a carboxyl group (COOH group) or a hydroxyl group (OH group) can also be used. Specifically, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, or 3,5-diaminobenzoic acid can be mentioned. Among them, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, or 3,5-diaminobenzoic acid is preferable. Further, a diamine compound represented by the following formulas [3b-1] to [3b-4] and a diamine compound having a secondary amino group as their amino group can be used.

[0090]

[0091] (In formula [3b-1], Q 1 represents a single bond, -CH 2 -, -C 2 H 4 -, -C(CH 3 ) 2 -, -CF 2 -, -C(CF 3 ) 2 -, -O-, -CO-, -NH-, -N(CH 3 )-, -CONH-, -NHCO-, -CH 2 O-, -OCH 2 -, -COO-, -OCO-, -CON(CH 3 )- or -N(CH 3 )CO-, m 1 and m 2 each independently represent an integer of 0 to 4, and m 1 +m 2 represents an integer of 1 to 4. In formula [3b-2], m 3 and m 4 each independently represent an integer of 1 to 5. In formula [3b-3], Q 2 represents a linear or branched alkylene group having 1 to 5 carbon atoms, and m 5 represents an integer of 1 to 5. In formula [3b-4], Q 3 and Q 4 each independently represent a single bond, -CH2 -, -C 2 H 4 -, -C(CH 3 ) 2 -, -CF 2 -, -C(CF 3 ) 2 -, -O-, -CO-, -NH-, -N(CH 3 )-, -CONH-, -NHCO-, -CH 2 O-、-OCH 2 -, -COO-, -OCO-, -CON(CH 3 )-or-N(CH 3 )CO-,m 6 Indicates an integer from 1 to 4. )

[0092] As the diamine component for obtaining the second polyamic acid, diamines used for specific polymers and known diamines can be used in addition to the above, but the present invention is not limited thereto. The diamine component for obtaining the second polyamic acid may be one diamine or two or more diamines may be used in combination.

[0093] <Production method of polyamic acid, polyamic acid ester, and polyimide>

[0094] The polyamic acid ester, the polyamic acid, and the polyimide which are polyimide precursors used in the present invention can be synthesized by a known method described in, for example, International Publication WO2013 / 157586.

[0095] <Liquid crystal alignment agent>

[0096] The liquid crystal aligning agent of the present invention contains a polymer (A). In addition to the polymer (A) and the desired second polymer, the liquid crystal aligning agent of the present invention may also contain other polymers. As the types of other polymers, polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivatives, polyacetals, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivatives, poly(meth)acrylates, etc. can be listed.

[0097] The liquid crystal alignment agent is used to make a liquid crystal alignment film. From the perspective of forming a uniform film, it is preferably in the form of a coating liquid. In the liquid crystal alignment agent of the present invention, a coating liquid containing the above-mentioned polymer component and an organic solvent is preferred. At this time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed according to the setting of the thickness of the coating film to be formed. From the perspective of forming a uniform and defect-free coating film, it is preferably more than 1% by mass, and from the perspective of the storage stability of the solution, it is preferably less than 10% by mass. The concentration of the polymer is particularly preferably 2 to 8% by mass.

[0098] The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as it is a solvent in which the polymer component can be uniformly dissolved. Specific examples thereof include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide (collectively referred to as "good solvents"), etc. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide or γ-butyrolactone is preferably used. The good solvent in the liquid crystal aligning agent of the present invention is preferably 20 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass of the total solvent contained in the liquid crystal aligning agent.

[0099] In addition, as the organic solvent contained in the liquid crystal aligning agent, a mixed solvent in which a solvent (also referred to as a poor solvent) that improves the coatability and the surface smoothness of the coating film when coating the liquid crystal aligning agent is preferably used in combination in addition to the solvents as described above. Specific examples of the organic solvents used in combination are listed below, but are not limited to these examples.

[0100] For example, they include diisopropyl ether, diisobutyl ether, diisobutyl carbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0101] Among them, diisobutyl carbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, and diisobutyl ketone are preferably used.

[0102] As preferred combinations of solvents as good solvents and poor solvents, the following can be cited: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and 2,6-dimethyl-4-heptanone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and 2,6-dimethyl-4-heptanol; N-methyl-2-pyrrolidone, γ-butyrolactone, and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol dimethyl ether, etc. These poor solvents are preferably 1 to 80% by mass, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass of the total solvents contained in the liquid crystal aligning agent. The type and content of such solvents are appropriately selected according to the coating device, coating conditions, coating environment, etc. of the liquid crystal aligning agent.

[0103] The liquid crystal aligning agent of the present invention may also additionally contain components other than the polymer component and the organic solvent. As such additional components, the following can be cited: adhesion aids for improving the adhesion between the liquid crystal alignment film and the substrate, and between the liquid crystal alignment film and the sealant, compounds for improving the strength of the liquid crystal alignment film (hereinafter also referred to as crosslinkable compounds), dielectrics for adjusting the dielectric constant and resistance of the liquid crystal alignment film, conductive substances, etc.

[0104] As the crosslinkable compound, from the viewpoints of less generation of AC afterimages and high improvement effect of film strength, a compound having at least one group selected from the group consisting of an oxiranyl group, an oxetanyl group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Meldrum Acid structure, a cyclic carbonate group, and a group represented by the following formula (d), or a compound selected from the compounds represented by the following formula (e) (hereinafter, they are also collectively referred to as compound (C).) is preferred.

[0105]

[0106] (In the formula, R 71 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "* - CH 2 - OH", R 72 and R 73 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "* - CH 2 - OH". * represents a bonding bond. A represents an (m + n)-valent organic group having an aromatic ring. m represents an integer of 1 to 6, and n represents an integer of 0 to 4.)

[0107] As specific examples of the compound having an oxiranyl group, for example, compounds having two or more oxiranyl groups such as the compounds described in paragraph

[0037] of Japanese Patent Laid-Open No. 10-338880 and compounds having a triazine ring in the skeleton described in International Publication WO2017 / 170483 can be cited. Among them, N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, and compounds containing a nitrogen atom such as the compounds represented by the following formulas (r-1) to (r-3) are particularly preferred.

[0108]

[0109] As specific examples of the compound having an oxetanyl group, for example, compounds having two or more oxetanyl groups described in paragraphs

[0170] to

[0175] of International Publication 2011 / 132751 can be cited.

[0110] As specific examples of the compound having a protected isocyanate group, for example, compounds having two or more protected isocyanate groups described in paragraphs

[0046] to

[0047] of Japanese Patent Laid-Open No. 2014-224978 and compounds having three or more protected isocyanate groups described in paragraphs

[0119] to

[0120] of International Publication 2015 / 141598 can be cited. Among them, the compounds represented by the following formulas (bi-1) to (bi-3) are preferred.

[0111]

[0112] As specific examples of the compound having a protected isothiocyanate group, for example, compounds having two or more protected isothiocyanate groups described in Japanese Patent Laid-Open No. 2016-200798 can be cited.

[0113] As specific examples of the compound having a group containing an oxazoline ring structure, for example, compounds containing two or more oxazoline structures described in paragraph

[0115] of Japanese Patent Application Laid-Open No. 2007-286597 can be cited.

[0114] As specific examples of the compound having a group containing a Meldrum's acid structure, for example, compounds having two or more Meldrum's acid structures described in International Publication WO2012 / 091088 can be cited.

[0115] As specific examples of the compound having a cyclic carbonate group, for example, compounds described in International Publication WO2011 / 155577 can be cited.

[0116] As for R in the above formula (d) 71 、R 72 、R 73 alkyl groups having 1 to 3 carbon atoms, for example, methyl, ethyl, and propyl can be cited.

[0117] As specific examples of the compound having a group represented by the above formula (d), for example, compounds having two or more groups represented by the above formula (d) described in International Publication WO2015 / 072554, paragraph

[0058] of Japanese Patent Application Laid-Open No. 2016-118753, compounds described in Japanese Patent Application Laid-Open No. 2016-200798, etc. can be cited. Among them, compounds represented by the following formulas (hd-1) to (hd-8) are preferred.

[0118]

[0119] As the (m + n)-valent organic group having an aromatic ring in A of the above formula (e), the following can be cited: (m + n)-valent aromatic hydrocarbon groups having 5 to 30 carbon atoms, (m + n)-valent organic groups in which an aromatic hydrocarbon group having 5 to 30 carbon atoms is bonded directly or via a linking group, and (m + n)-valent groups having an aromatic heterocycle. As the aromatic hydrocarbon group, for example, benzene, naphthalene, etc. can be cited. As the aromatic heterocycle, for example, the following can be cited: pyrrole ring, imidazole ring, pyrazole ring, pyridine ring, pyrimidine ring, quinoline ring, isoquinoline ring, carbazole ring, pyridazine ring, pyrazine ring, benzimidazole ring, benzimidazole ring, indole ring, quinoxaline ring, acridine ring, etc. As the linking group, the following can be cited: alkylene groups having 1 to 10 carbon atoms, or groups obtained by removing one hydrogen atom from the alkylene group, divalent or trivalent cyclohexane rings, etc. It should be noted that any hydrogen atom of the alkylene group is optionally substituted with an organic group such as a fluorine atom or a trifluoromethyl group. If specific examples are cited, compounds described in International Publication WO2010 / 074269 can be cited. As preferred specific examples, the following formulas (e-1) to (e-9) can be cited.

[0120]

[0121] The above compound is an example of a crosslinkable compound, but is not limited thereto. For example, components other than the above disclosed on pages 53 to 55 of International Publication No. 2015 / 060357 can be cited. In addition, the crosslinkable compound contained in the liquid crystal aligning agent of the present invention may be one kind, or two or more kinds may be combined.

[0122] The content of the crosslinkable compound in the liquid crystal aligning agent of the present invention is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, based on 100 parts by mass of the polymer component contained in the liquid crystal aligning agent, from the viewpoints of promoting the crosslinking reaction, achieving the target effect, and reducing the generation of AC afterimages.

[0123] Examples of the adhesion promoter include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diaza-nonyl acetate, 9-triethoxysilyl-3,6-diaza-nonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxyethylene)-3-aminopropyltrimethoxysilane, N-bis(oxyethylene)-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane and other silane coupling agents. When using these silane coupling agents, from the viewpoint of less generation of AC afterimages, it is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, based on 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0124] <Liquid Crystal Alignment Film / Liquid Crystal Display Element>

[0125] A liquid crystal alignment film can be manufactured by using the above liquid crystal aligning agent. In addition, the liquid crystal display element of the present invention includes a liquid crystal alignment film formed by using the above liquid crystal aligning agent. The operation mode of the liquid crystal display element of the present invention is not particularly limited, and for example, it can be applied to various operation modes such as TN (Twisted Nematic) type, STN type, vertical alignment type (including VA-MVA type, VA-PVA type, etc.), in-plane switching type (IPS type), FFS (Fringe Field Switching) type, optically compensated bend type (OCB type: Optically Compensated Birefringence type).

[0126] The liquid crystal display element of the present invention can be manufactured, for example, by a process including the following processes (1-1) to (1-3). In process (1-1), different substrates are used according to the desired operation mode. Processes (1-2) and (1-3) are common to each operation mode.

[0127] [Process (1-1): Formation of a coating film]

[0128] First, the liquid crystal aligning agent of the present invention is coated on a substrate, and then the coated surface is heated to form a coating film on the substrate.

[0129] (1-1A)

[0130] For example, in the case of manufacturing a TN-type, STN-type, or VA-type liquid crystal display element, first, two substrates provided with patterned transparent conductive films are used as a pair, and the liquid crystal aligning agent prepared above is respectively coated on the respective transparent conductive film forming surfaces by, preferably, offset printing method, spin coating method, roll coater, or inkjet printing method. As the substrate, for example, a transparent substrate made of glass such as float glass, soda glass, etc.; or a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly(alicyclic olefin) can be used. As the transparent conductive film provided on one surface of the substrate, a NESA film (registered trademark of PPG Industries, Inc., USA) made of tin oxide (Sn 2 ) or indium tin oxide (In 2 O 3 -SnO 2)ITO films and the like. In order to obtain a patterned transparent conductive film, for example, the following methods can be used: after forming the transparent conductive film without a pattern, forming a pattern by photolithography; when forming the transparent conductive film, using a mask with a desired pattern; and so on. When coating the liquid crystal aligning agent, in order to further improve the adhesion between the substrate surface, the transparent conductive film and the coating film, a pretreatment can also be performed by pre-coating a functional silane compound, a functional titanium compound, etc. on the surface of the substrate where the coating film is to be formed.

[0131] After coating the liquid crystal aligning agent, for the purpose of preventing the liquid of the coated liquid crystal aligning agent from running off, etc., preheating (pre-baking) is preferably performed. The pre-baking temperature is preferably 30 to 200 °C, more preferably 40 to 150 °C, and particularly preferably 40 to 100 °C. The pre-baking time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Then, the solvent is completely removed, and if necessary, for the purpose of thermally imidizing the amic acid structure present in the polymer, a firing (post-baking) process is performed. The firing temperature (post-baking temperature) at this time is preferably 80 to 300 °C, more preferably 120 to 250 °C. The post-baking time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The film thickness of the film thus formed is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.

[0132] (1-1B)

[0133] In the case of manufacturing an IPS type or FFS type liquid crystal display element, the liquid crystal aligning agent is respectively coated on the electrode forming surface of a substrate provided with an electrode composed of a patterned comb-shaped transparent conductive film or a metal film and on one surface of a counter substrate without an electrode, and then each coated surface is heated to form a coating film. Regarding the materials of the substrate and the transparent conductive film used at this time, the coating method, the heating conditions after coating, the patterning method of the transparent conductive film or the metal film, the pretreatment of the substrate, and the preferred film thickness of the formed coating film, they are the same as those in the above (1-1A). As the metal film, for example, a film composed of a metal such as chromium can be used.

[0134] In any of the above (1-1A) and (1-1B), after coating the liquid crystal aligning agent on the substrate, the organic solvent is removed to form a liquid crystal alignment film or a coating film that becomes a liquid crystal alignment film. At this time, after forming the coating film, heating can also be further performed to cause the dehydration ring-closure reaction of the polyamic acid, polyamic acid ester, and polyimide incorporated in the liquid crystal aligning agent of the present invention to proceed, and a further imidized coating film can be formed.

[0135] [Process (1-2): Alignment ability imparting treatment]

[0136] In the case of manufacturing a liquid crystal display element of the TN type, STN type, IPS type, or FFS type, a treatment for imparting liquid crystal alignment ability is performed on the coating film formed in the above step (1-1). Thereby, the coating film is imparted with the alignment ability of liquid crystal molecules and becomes a liquid crystal alignment film. As the alignment ability imparting treatment, for example, there can be mentioned: a brushing treatment in which a cloth made of fibers such as nylon, rayon, and cotton is wound and the coating film is rubbed in a certain direction; a photo-alignment treatment in which polarized or non-polarized radiation is irradiated on the coating film, etc. On the other hand, in the case of manufacturing a VA type liquid crystal display element, the coating film formed in the above step (1-1) can be directly used as a liquid crystal alignment film, or a treatment for imparting alignment ability can be performed on the coating film.

[0137] In the case of imparting liquid crystal alignment ability to the coating film by photo-alignment treatment, as the radiation irradiated on the coating film, for example, ultraviolet rays and visible light including light having a wavelength of 150 to 800 nm can be used. When the radiation is polarized, it can be linearly polarized or partially polarized. Further, when the radiation used is linearly polarized or partially polarized, the irradiation can be performed from a direction perpendicular to the substrate surface, from an inclined direction, or they can be combined. When non-polarized radiation is irradiated, the irradiation direction is set to an inclined direction.

[0138] As the light source used, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. can be used. Ultraviolet rays in a preferred wavelength region can be obtained by a method such as using the light source in combination with a filter, a diffraction grating, etc. The irradiation amount of the radiation is preferably 10 to 5000 mJ / cm 2 and more preferably 30 to 2000 mJ / cm 2 .

[0139] Further, in order to improve the reactivity, the photo-irradiation of the coating film can be performed while heating the coating film. The temperature during heating is usually 30 to 250°C, preferably 40 to 200°C, and more preferably 50 to 150°C.

[0140] Further, in the case of using ultraviolet rays including light having a wavelength of 150 to 800 nm, the photo-irradiated film obtained in the above step can be directly used as a liquid crystal alignment film, or firing, cleaning with water or an organic solvent, or a combination thereof can be performed on the photo-irradiated film. The firing temperature at this time is preferably 80 to 300°C, and more preferably 80 to 250°C. The firing time is preferably 5 to 200 minutes, and more preferably 10 to 100 minutes. It should be noted that the number of times of firing can be one or more than two. The photo-alignment treatment here corresponds to the treatment of photo-irradiation in a state where it is not in contact with the liquid crystal layer.

[0141] The organic solvent used in the above cleaning is not particularly limited. As specific examples, the following can be cited: water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, or cyclohexyl acetate, etc.

[0142] It should be noted that the liquid crystal alignment film after the rubbing treatment can also be further processed as follows to make each region of the liquid crystal alignment film have different liquid crystal alignment capabilities. The treatment is: a treatment for changing the pretilt angle of a part of the region of the liquid crystal alignment film by irradiating ultraviolet light on a part of the liquid crystal alignment film; a treatment for removing the protective film after performing a rubbing treatment in a direction different from the previous rubbing treatment on the basis that a protective (rasist) film is formed on a part of the surface of the liquid crystal alignment film. In this case, the viewing characteristics of the obtained liquid crystal display element can be improved. The liquid crystal alignment film preferred in the VA type liquid crystal display element can also be preferably used in the PSA (Polymer sustained alignment) type liquid crystal display element.

[0143] [Process (1-3): Construction of liquid crystal cell (cell)]

[0144] (1-3A)

[0145] As described above, two substrates formed with liquid crystal alignment films are prepared, and liquid crystal is disposed between the two substrates disposed opposite to each other, thereby manufacturing a liquid crystal cell. For manufacturing a liquid crystal cell, for example, the following two methods can be cited. The first method is a method well-known in the past. First, the two substrates are disposed opposite to each other with a gap (cell gap) therebetween in such a manner that the liquid crystal alignment films face each other, the peripheral portions of the two substrates are bonded using a sealant, and after injecting and filling the liquid crystal into the cell gap defined by the substrate surface and the sealant, the injection hole is sealed, thereby manufacturing a liquid crystal cell. The second method is a method called the ODF (One Drop Fill) method. An ultraviolet curable sealant is coated at a specified position on one of the two substrates formed with liquid crystal alignment films, and after further dropping the liquid crystal at several specified portions on the liquid crystal alignment film surface, the other substrate is bonded in such a manner that the liquid crystal alignment films face each other, and the liquid crystal is spread over the entire surface of the substrate. Then, ultraviolet light is irradiated on the entire surface of the substrate to cure the sealant, thereby manufacturing a liquid crystal cell. In either case, it is desired that for the liquid crystal cell manufactured as described above, the liquid crystal used is further heated to an isotropic temperature and then slowly cooled to room temperature, thereby removing the flow alignment during liquid crystal filling.

[0146] As the sealant, for example, an epoxy resin containing a curing agent and alumina balls as spacers can be used.

[0147] Examples of the liquid crystal include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred. For example, Schiff base liquid crystals, azoxy liquid crystals, biphenyl liquid crystals, phenylcyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals, biphenylcyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, cubane liquid crystals, etc. can be used. In addition, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonanoate, and cholesteryl carbonate can be added to these liquid crystals; chiral agents sold under the trade names "C-15" and "CB-15" (manufactured by MERCK); and strongly dielectric liquid crystals such as p-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate. In addition, the liquid crystal can additionally contain anisotropic dyes. The term "dye" refers to a substance that can absorb at least a part or the whole range of light or distort it intensively within the visible light region, for example, within the wavelength range of 400 nm or 700 nm. The term "anisotropic dye" refers to a substance that can absorb light anisotropically within at least a part or the whole range of the visible light region.

[0148] The color sense of the liquid crystal cell can be adjusted by using the above-mentioned dyes. The type of the anisotropic dye is not particularly limited. For example, a black dye or a color dye can be used. Within the range of not impairing the physical properties, the ratio of the anisotropic dye to the liquid crystal can be appropriately selected. For example, the anisotropic dye can be contained in a ratio of 0.01 parts by weight to 5 parts by weight based on 100 parts by weight of the liquid crystal compound, and this ratio can be changed within an appropriate range as needed.

[0149] (1-3B)

[0150] In the case of manufacturing a PSA type liquid crystal display element, in addition to injecting or dropping a photopolymerizable compound such as the following formulas (w-1) to (w-5) together with the liquid crystal, the liquid crystal cell is constructed in the same manner as in the above (1-3A).

[0151]

[0152] Then, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of a pair of substrates. The voltage applied here can be, for example, a direct current or an alternating current of 5 to 50 V. In addition, as the light for irradiation, for example, ultraviolet rays and visible light including light having a wavelength of 150 to 800 nm can be used, but ultraviolet rays including light having a wavelength of 300 to 400 nm are preferred. As the light source for the irradiation light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. can be used. It should be noted that the ultraviolet rays in the above-mentioned preferred wavelength region can be obtained by a method such as using the light source in combination with a filter, a diffraction grating, etc. As the irradiation amount of light, it is preferably 100 mJ / cm 2 or more and less than 30000 mJ / cm 2 , and more preferably 100 to 20000 mJ / cm 2 .

[0153] (1-3C)

[0154] In the case of forming a coating film on a substrate using a liquid crystal aligning agent containing a compound (polymer or additive) having a photopolymerizable group, a liquid crystal cell is constructed in the same manner as in the above (1-3A), and thereafter, the following method can also be adopted: a method of manufacturing a liquid crystal display element by passing through a step of irradiating the liquid crystal cell with light while a voltage is applied between the conductive films of a pair of substrates. According to this method, the advantages of the PSA mode can be achieved with a small amount of light irradiation. The light irradiation of the liquid crystal cell can be performed in a state where the liquid crystal is driven by applying a voltage, or can also be performed in a state where a low voltage is applied to such an extent that the liquid crystal is not driven. The voltage applied can be, for example, a direct current or an alternating current of 0.1 to 30 V. Regarding the conditions of the irradiated light, the description of the above (1-3B) can be applied. The light irradiation treatment here corresponds to the light irradiation treatment in a state of being in contact with the liquid crystal layer.

[0155] Furthermore, by attaching a polarizing plate to the outer surface of the liquid crystal cell, the liquid crystal display element of the present invention can be obtained. As the polarizing plate attached to the outer surface of the liquid crystal cell, there can be mentioned: a polarizing plate formed by sandwiching a polyvinyl alcohol stretched and oriented while absorbing iodine with a cellulose acetate protective film on one side, which is called an "H film"; or a polarizing plate composed of the H film itself.

[0156] The liquid crystal display element of the present invention can be effectively used in various devices. For example, it can be used in various display devices such as clocks, portable game consoles, word processors, notebook computers, in-vehicle navigation systems, camcorders, PDAs (Personal Digital Assistants), digital cameras, mobile phones, smartphones, various monitors, liquid crystal TVs, and information displays.

[0157] As described above, by using the liquid crystal aligning agent of the present invention, a liquid crystal alignment film with less generation of afterimages and minimizing bright spots even when physical friction such as scratching caused by spacers occurs, and a liquid crystal display element having the liquid crystal alignment film can be obtained. In addition, the obtained liquid crystal display element has high reliability.

[0158] Examples

[0159] Examples are listed below to further illustrate the present invention in detail, but the present invention is not limited thereto. The abbreviations of the compounds used are as described below.

[0160] (Liquid crystal)

[0161] MLC-3019 (manufactured by MERCK, positive-type liquid crystal).

[0162] (Diamine compound)

[0163] WA-1: The compound represented by formula [WA-1].

[0164] WA-2: The compound represented by formula [WA-2].

[0165]

[0166] (Other diamine compounds)

[0167] A1 to A7: Compounds represented by formula [A1] to formula [A7], respectively.

[0168]

[0169] (Boc represents tert-butoxycarbonyl.)

[0170] (Acid dianhydride compound)

[0171] B1 to B3: Compounds represented by formula [B1] to formula [B3], respectively.

[0172]

[0173] (Solvent)

[0174] NMP: N-methyl-2-pyrrolidone.

[0175] BCS: ethylene glycol monobutyl ether.

[0176] GBL: γ-butyrolactone.

[0177] (Additive)

[0178] S-1: 3-glycidoxypropyltriethoxysilane.

[0179] (Crosslinking agent)

[0180] AD-1: the compound represented by the following formula (AD-1).

[0181]

[0182] (Molecular weight measurement)

[0183] Using a normal temperature gel permeation chromatography (GPC) device (GPC-101, manufactured by Showa Denko K.K.) and chromatographic columns (KD-803, KD-805, manufactured by Shodex), the molecular weights of the polyimide precursor and polyimide were measured as described below.

[0184] Column temperature: 50 °C.

[0185] Eluent: N,N-dimethylformamide (as an additive, lithium bromide monohydrate (LiBr·H 2 O) is 30 mmol / L (liter), phosphoric acid / anhydrous crystal (o-phosphoric acid) is 30 mmol / L, and tetrahydrofuran (THF) is 10 mL / L).

[0186] Flow rate: 1.0 mL / minute.

[0187] Standard samples for calibration curve preparation: TSK standard polyethylene oxide (molecular weights: approximately 900,000, 150,000, 100,000, and 30,000, manufactured by Tosoh Corporation) and polyethylene glycol (molecular weights: approximately 12,000, 4,000, and 1,000, manufactured by Polymer Laboratory).

[0188] (Measurement of imidization rate of polyimide)

[0189] To an NMR (nuclear magnetic resonance) sample tube (NMR standard sampling tube, φ5 (manufactured by Kusano Kagaku Co., Ltd.)), 20 mg of polyimide powder was added, and deuterated dimethyl sulfoxide (DMSO-d6, a mixture containing 0.05 mass% TMS (tetramethylsilane)) (0.53 mL) was added, and ultrasonic waves were applied to completely dissolve it. The proton NMR at 500 MHz of this solution was measured using an NMR measuring machine (JNW-ECA500) (manufactured by JEOL DATUM Co., Ltd.). The imidization rate was determined as follows: The protons derived from the structure that does not change before and after imidization were determined as reference protons, and using the peak integral value of this proton and the peak integral value of the protons of the NH group of amic acid that appears around 9.5 to 10.0 ppm, it was determined using the following formula.

[0190] Imidization rate (%) = (1 - α·x / y) × 100

[0191] In the above formula, x is the peak integral value of the protons of the NH group of amic acid, y is the peak integral value of the reference protons, and α is the ratio of the number of reference protons to one NH group proton of amic acid in the case of polyamic acid (imidization rate is 0%).

[0192] (Viscosity measurement)

[0193] In the synthesis examples or comparative synthesis examples, for the viscosity of the polyimide-based polymer, an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) was used, and the measurement was carried out at a sample volume of 1.1 mL, a conical rotor TE-1 (1°34’, R24), and a temperature of 25 °C.

[0194] (WA-1) The synthesis was carried out with reference to the following existing literature.

[0195] Salvatore Zarra, Jack K. Clegg, Jonathan R. Nitschke, Angewandte Chemie International Edition, 52, 18, (4837 - 4840, Supporting Information: S2 - S3), (2013).

[0196] (WA-2) It is a new compound not disclosed in the literature, etc., and the synthesis method is described in detail below.

[0197] The product described in Synthesis Example 1 below was identified by 1 H-NMR analysis (the analysis conditions are as described below).

[0198] Apparatus: BRUKER ADVANCE III - 500 MHz.

[0199] Measuring solvent: DMSO-d 6 .

[0200] Reference substance: Tetramethylsilane (TMS) (δ 0.0 ppm for 1 H).

[0201] The abbreviations in the present invention respectively represent the following meanings.

[0202] THF: Tetrahydrofuran.

[0203] DCE: 1,2-Dichloroethane.

[0204] DMAP: N,N-Dimethyl-4-aminopyridine.

[0205] <<Synthesis of Monomer Synthesis Example 1 WA-2>>

[0206]

[0207] <<Synthesis of Compound [1]>>

[0208] To 1,2-dichloroethane (540 g), (4,4'-dinitro-[1,1'-biphenyl]-2,2'-diyl) dimethanol (60.0 g, 0.197 mol), triethylamine (45.9 g, 0.454 mol), and N,N-dimethyl-4-aminopyridine (2.39 g, 0.0197 mol) were added, and the mixture was stirred under ice-cooling conditions. Di-tert-butyl dicarbonate (94.7 g, 0.434 mol) diluted with 1,2-dichloroethane (60 g) was added dropwise while paying attention to heat generation. After the heat generation stopped, the mixture was stirred overnight at room temperature. After the reaction was completed, stirring was stopped, water (600 g) was added for liquid separation and washing, and liquid separation extraction was performed using chloroform (300 g × 2 times). The organic phase was concentrated, and the obtained crude product was purified by silica gel column chromatography using an ethyl acetate / hexane = 2 / 1 (volume ratio) mixed solvent. The obtained solution was concentrated and dried to obtain a crude product of compound [1] (yield: 102 g). The obtained compound was directly used in the next step.

[0209] 1 H-NMR (500 MHz) in DMSO-d 6 : 8.41 ppm (s, 2H), 8.33 ppm (d, 2H, J = 8.5 Hz), 7.58 ppm (d, 2H, J = 8.5 Hz), 4.90 ppm (s, 4H), 1.39 ppm (s, 18H).

[0210] <<Synthesis of WA-2>>

[0211] To tetrahydrofuran (600 g), the crude product of compound [1] (101 g) and 3% platinum on carbon (hydrous product) (8.00 g) were added, and the mixture was stirred overnight under a hydrogen atmosphere at room temperature. After the reaction was completed, the platinum on carbon was removed by filtration, and concentration under reduced pressure was carried out. Methanol was added to the crude product and concentration was carried out again, followed by drying to obtain WA-2 (yield: 86.6 g, 0.195 mol).

[0212] 1 H-NMR (500 MHz) in DMSO-d 6 : 6.72 ppm (d, 2H, J = 8.0 Hz), 6.63 ppm (d, 2H, J = 2.5 Hz), 6.52 ppm (d, 1H, J = 2.5 Hz), 6.50 ppm (d, 1H, J = 2.0 Hz), 5.15 ppm (s, 4H), 4.64 - 4.59 ppm (m, 4H), 1.34 ppm (s, 18H).

[0213] (Synthesis Example 1)

[0214] WA-1 (2.19 g, 9.00 mmol), A1 (1.83 g, 7.50 mmol), A2 (1.72 g, 7.50 mmol), A4 (2.04 g, 6.00 mmol) and B2 (1.12 g, 4.50 mmol) were mixed in NMP (50.6 g), and the mixture was reacted at 50 °C for 3 hours. Then, B1 (5.32 g, 23.7 mmol) and NMP (30.1 g) were added, and the mixture was reacted at 40 °C for 15 hours to obtain a polyamic acid solution [1] with a resin solid content concentration of 15% by mass (viscosity 384 mPa·s).

[0215] To the obtained polyamic acid solution [1] (30.0 g), NMP was added to dilute it to 10.0% by mass, and then acetic anhydride (4.83 g) and pyridine (1.50 g) as imidization catalysts were added, and the mixture was reacted at 55 °C for 2.5 hours. The reaction solution was poured into methanol (280 mL), and the obtained precipitate was filtered out. The precipitate was washed with methanol and dried under reduced pressure at 100 °C to obtain polyimide powder (1). The imidization rate of this polyimide was 78.1%, the number average molecular weight was 12322, and the weight average molecular weight was 44438.

[0216] (Synthesis Example 2)

[0217] WA-2 (4.00 g, 9.00 mmol), A1 (1.83 g, 7.50 mmol), A2 (1.72 g, 7.50 mmol), A4 (2.04 g, 6.00 mmol), and B2 (1.12 g, 4.50 mmol) were mixed in NMP (50.6 g). After reacting at 50 °C for 3 hours, B1 (5.32 g, 23.7 mmol) and NMP (30.1 g) were added, and the mixture was reacted at 40 °C for 15 hours to obtain a polyamic acid solution [2] with a resin solid content concentration of 15% by mass (viscosity: 188 mPa·s).

[0218] To the obtained polyamic acid solution [2] (30.0 g), NMP was added to dilute it to 10.0% by mass. Then, acetic anhydride (4.83 g) and pyridine (1.50 g) as imidization catalysts were added, and the mixture was reacted at 55 °C for 2.5 hours. The reaction solution was poured into methanol (280 mL), and the resulting precipitate was filtered out. The precipitate was washed with methanol and dried under reduced pressure at 100 °C to obtain polyimide powder (2). The imidization rate of this polyimide was 80.1%, the number average molecular weight was 10582, and the weight average molecular weight was 41856.

[0219] (Synthesis Example 3)

[0220] A6 (1.19 g, 6.00 mmol), A7 (4.78 g, 24.0 mmol), and B2 (3.75 g, 15.0 mmol) were mixed in NMP (55.1 g). After reacting at 50 °C for 3 hours, B3 (4.06 g, 13.8 mmol) and NMP (23.0 g) were added, and the mixture was reacted at 70 °C for 15 hours to obtain a polyamic acid solution [3] with a resin solid content concentration of 15% by mass (viscosity: 941 mPa·s).

[0221] The number average molecular weight of the polyamic acid solution [3] was 15244, and the weight average molecular weight was 40724.

[0222] (Comparative Synthesis Example 1)

[0223] A5 (1.91 g, 9.00 mmol), A1 (1.83 g, 7.50 mmol), A2 (1.72 g, 7.50 mmol), A4 (2.04 g, 6.00 mmol), and B2 (1.12 g, 4.50 mmol) were mixed in NMP (50.6 g). After reacting at 50 °C for 3 hours, B1 (5.32 g, 23.7 mmol) and NMP (30.1 g) were added, and the mixture was reacted at 40 °C for 15 hours to obtain a polyamic acid solution [R1] with a resin solid content concentration of 15% by mass (viscosity: 365 mPa·s).

[0224] To the obtained polyamic acid solution [R1] (30.0 g), NMP was added, and after diluting to 10.0 mass%, acetic anhydride (4.83 g) and pyridine (1.50 g) were added as imidization catalysts, and the reaction was carried out at 55 °C for 2.5 hours. The reaction solution was poured into methanol (280 mL), and the obtained precipitate was filtered out. The precipitate was washed with methanol and dried under reduced pressure at 100 °C to obtain polyimide powder (R1). The imidization rate of this polyimide was 76.1%, the number average molecular weight was 10958, and the weight average molecular weight was 39958.

[0225] <Preparation of liquid crystal aligning agent>

[0226] In the examples and comparative examples, preparation examples of liquid crystal aligning agents are described. Using the liquid crystal aligning agents obtained in the examples and comparative examples, liquid crystal display elements were fabricated and various evaluations were performed.

[0227] (Example 1)

[0228] To the polyimide powder (1) (3.00 g) obtained in Synthesis Example 1, NMP (22.0 g) was added, and it was stirred at 80 °C for 15 hours to dissolve. To this solution (2.75 g), the polyamic acid solution [3] (3.30 g) obtained in Synthesis Example 3, NMP (1.35 g), GBL (3.675 g), BCS (3.00 g), a 10 mass% NMP-diluted solution of AD-1 (0.248 g), and a 1 mass% GBL-diluted solution of S-1 (0.825 g) were added, and it was stirred at room temperature for 5 hours to obtain a liquid crystal aligning agent (V-1). No abnormalities such as turbidity and precipitation were observed in this liquid crystal aligning agent, and it was confirmed to be a uniform solution.

[0229] (Example 2)

[0230] Except that polyimide powder (2) was used instead of polyimide powder (1) in Example 1, a liquid crystal aligning agent (V-2) was obtained in the same manner as in Example 1. No abnormalities such as turbidity and precipitation were observed in this liquid crystal aligning agent, and it was confirmed to be a uniform solution.

[0231] (Comparative Example 1)

[0232] Except that polyimide powder (R1) was used instead of polyimide powder (1) in Example 1, a liquid crystal aligning agent (W-1) was obtained in the same manner as in Example 1. No abnormalities such as turbidity and precipitation were observed in this liquid crystal aligning agent, and it was confirmed to be a uniform solution.

[0233] <Fabrication of samples for evaluating sealing tightness>

[0234] The samples for evaluating the sealing property were prepared as follows. By spin coating, the liquid crystal aligning agents (V-1) and (V-2) obtained in the examples and the liquid crystal aligning agent (W-1) obtained in the comparative example were coated on a 30 mm × 40 mm ITO substrate. After drying on a hot plate at 80°C for 120 seconds, it was fired in a hot air circulation oven at 230°C for 20 minutes to form a coating film with a thickness of 100 nm, and a substrate with a liquid crystal alignment film was obtained.

[0235] Two such obtained substrates were prepared. After coating 4-μm-diameter bead spacers on the liquid crystal alignment film surface of one substrate, a sealant (XN-1500T manufactured by Kyoretsu Chemical Industry Co., Ltd.) was dropped. Then, with the liquid crystal alignment film surface of the other substrate facing inward, they were bonded in such a way that the overlapping width around the substrate was 1 cm each. At this time, the dropping amount of the sealant was adjusted so that the diameter of the sealant after bonding was 3 mm. After fixing the two bonded substrates with a jig, light with a wavelength of 365 nm of 3 J was irradiated, and it was thermally cured at 120°C for 1 hour to produce a sample for evaluating the sealing property.

[0236] <Evaluation of Sealing Property>

[0237] Then, the sample substrate obtained above was pressed from the upper part of the center of the substrate after fixing the ends of the upper and lower substrates using a bench-top precision universal testing machine AGS-X500N manufactured by Shimadzu Corporation, and the force (N) at the time of peeling was measured. The case where (N) is less than 3.50 was defined as "poor", and the case where (N) is 3.50 or more was defined as "good". The results are shown in Table 1.

[0238] <Evaluation of Film Strength (Film Hardness)>

[0239] By spin coating, the liquid crystal aligning agent was coated on the ITO surface of a glass substrate with an ITO electrode on the entire surface. After drying it on a hot plate at 80°C for 2 minutes, a coating film with a thickness of 100 nm was formed. Polarized ultraviolet rays were irradiated on this coating film surface to a dose of 150 mJ / cm 2 to perform an alignment treatment. Then, it was fired at 230°C for 30 minutes using an IR oven to obtain a substrate with a liquid crystal alignment film. This liquid crystal alignment film was rubbed with a rayon cloth (roller diameter: 120 mm, roller rotation speed: 1000 rpm, moving speed: 20 mm / sec, pressing length: 0.6 mm). This substrate was measured using an HZ-V3 haze meter manufactured by SUGA Test Instruments Co., Ltd. The case where the haze value is 0.3 or more was defined as "poor", and the case where the haze value is less than 0.3 was defined as "good" for evaluation. The results are shown in Table 1.

[0240] <Fabrication of Liquid Crystal Cell for Evaluating Liquid Crystal Alignment>

[0241] Hereinafter, a method for manufacturing a liquid crystal cell for evaluating liquid crystal alignment is shown.

[0242] A liquid crystal cell having a configuration of a liquid crystal display element of the FFS mode is manufactured. First, a substrate with electrodes is prepared. The substrate is a glass substrate with a size of 30 mm × 35 mm and a thickness of 0.7 mm. On the substrate, as the first layer, an IZO electrode constituting a counter electrode is formed over the entire surface. On the counter electrode of the first layer, as the second layer, a SiN (silicon nitride) film formed by CVD method is formed. The film thickness of the SiN film of the second layer is 500 nm, which functions as an interlayer insulating film. On the SiN film of the second layer, as the third layer, comb-shaped pixel electrodes formed by patterning an IZO film are arranged to form two types of pixels, a first pixel and a second pixel. The size of each pixel is 10 mm in length and about 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

[0243] The pixel electrode of the third layer has a comb shape formed by arranging a plurality of < symbol-shaped electrode elements with a bent central portion, similar to the drawings described in Japanese Unexamined Patent Application Publication No. 2014 - 77845 (Japanese Patent Publication Gazette). The width of each electrode element in the short dimension direction is 3 μm, and the interval between electrode elements is 6 μm. Since the pixel electrodes forming each pixel are configured to arrange a plurality of < symbol-shaped electrode elements with a bent central portion, the shape of each pixel is not rectangular, but has a shape similar to a bold < symbol with a bend in the central portion similar to the electrode element. And each pixel is divided vertically with the bent portion in the center as a boundary, having a first region on the upper side and a second region on the lower side of the bent portion.

[0244] Comparing the first region and the second region of each pixel, the formation directions of the electrode elements constituting their pixel electrodes are different. That is, in the case of taking the direction of the line segment on which the polarization plane of the polarized ultraviolet light described later is projected onto the substrate as a reference, in the first region of the pixel, the electrode elements of the pixel electrode are formed at an angle of +80° (clockwise), and in the second region of the pixel, the electrode elements of the pixel electrode are formed at an angle of -80° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotational movement (in-plane / switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode in the substrate plane are configured to be opposite to each other.

[0245] Next, after filtering the liquid crystal aligning agents obtained in the synthesis example and the comparative synthesis example using a 1.0 μm filter, they were spin-coated and applied onto the above-prepared substrate with electrodes. Next, they were dried on a hot plate set at 80°C for 120 seconds. Next, using an exposure apparatus manufactured by USHIO Electric Inc.: APL-L050121S1S-APW01, linearly polarized ultraviolet light was irradiated onto the substrate from the vertical direction through a wavelength selection filter and a polarizer. At this time, the direction of the polarization plane was set as follows: the direction in which the polarization plane of the polarized ultraviolet light was projected onto the line segment of the substrate was a direction inclined 80° with respect to the third-layer IZO comb electrode. Next, they were fired in an IR (infrared) oven at 230°C for 30 minutes to obtain a substrate with a polyimide liquid crystal alignment film having a film thickness of 100 nm that had undergone alignment treatment. In addition, as a counter substrate, a substrate with a polyimide liquid crystal alignment film was obtained, and this substrate with a polyimide liquid crystal alignment film was also subjected to the same alignment treatment as above on a glass substrate having columnar spacers with a height of 4 μm and having an ITO electrode formed on the back surface. These two substrates with liquid crystal alignment films were set as a group, and a sealant was printed in a form with a liquid crystal injection port left on one substrate, and the other substrate was bonded and crimped with the liquid crystal alignment film surfaces facing each other and the direction in which the polarization plane of the polarized ultraviolet light was projected onto the line segment of the substrate being parallel. Then, the sealant was cured to fabricate an empty cell with a cell gap of 4 μm. Liquid crystal MLC-3019 (a positive liquid crystal manufactured by MERCK) was injected into this empty cell by a reduced-pressure injection method, and the injection port was sealed to obtain a liquid crystal cell in the FFS mode. Then, the obtained liquid crystal cell was heated at 120°C for 30 minutes, and after being left overnight at 23°C, it was used for evaluating the liquid crystal alignment property.

[0246] <Evaluation of Liquid Crystal Alignment Property>

[0247] Using this liquid crystal cell, the case where flow alignment could be confirmed was defined as "poor", and the case where flow alignment could not be confirmed was defined as "good". The results are shown in Table 1.

[0248] [Table 1]

[0249]

[0250] From the above results, it can be seen that in the adhesion evaluation, the liquid crystal alignment film obtained from the liquid crystal aligning agent using diamine compounds WA-1 and WA-2 showed higher adhesion compared to the liquid crystal alignment film obtained from the liquid crystal aligning agent using diamine compound A5. Specifically, it was reflected in the comparison between Examples 1-2 and Comparative Example 1 shown in Table 1.

[0251] Moreover, in the evaluation of the film strength, it was found that the liquid crystal alignment film obtained from the liquid crystal aligning agent using diamine compounds WA-1 and WA-2 exhibited higher film strength compared to the liquid crystal alignment film obtained from the liquid crystal aligning agent using diamine compound A5. Specifically, this was demonstrated in the comparison of Examples 1 to 2 and Comparative Example 1 shown in Table 1.

[0252] Furthermore, it was found that the liquid crystal alignment film obtained from the liquid crystal aligning agent using diamine compounds WA-1 and WA-2 exhibited equivalent liquid crystal alignment properties compared to the liquid crystal alignment film obtained from the liquid crystal aligning agent using diamine compound A5.

[0253] Based on the above, when using WA-1 and WA-2 having a biphenyl skeleton and a specific side chain, it is possible to improve the hermetic sealability and film strength while maintaining the liquid crystal alignment properties.

[0254] Industrial Applicability

[0255] The liquid crystal display element using the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention can be preferably used for liquid crystal display elements. Moreover, these elements are useful in liquid crystal displays for display purposes, and are further useful in dimming windows and optical shutters that control the transmission and blocking of light.

Claims

1. A diamine having a structure represented by the following formula (1): In formula (1), A represents an alkyl group having 1 to 3 carbon atoms, benzyl, p-methoxybenzyl, acetyl, benzoyl, tert-butoxycarbonyl, 9-fluorenylmethoxycarbonyl, or R 1 R 2 R 3 The Si group, R 1 , R 2 And R 3 Each independently represents an alkyl group having 1 to 3 carbon atoms or a phenyl group.

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