JP2018155920A - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal aligning agent excellent in rubbing resistance, and a liquid crystal alignment film obtained from the liquid crystal aligning agent.SOLUTION: The liquid crystal aligning agent comprises: a polymer (P) synthesized by using a diamine (I) having at least one partial structure (p) selected from a methacryl group, acryl group, vinyl group, substituted vinyl group substituted with a hydrocarbon group having 1 to 12 carbon atoms, and cinnamoyl group in a side chain and a diamine (II) having a partial structure represented by formula (H) below; and an organic solvent. In the formula, Rrepresents a protecting group of an amino group; and two of *1 represent bonding hands to be bonded to a hydrocarbon group or a hydrogen atom, where at least one bonding hand is to be bonded to a hydrocarbon group.SELECTED DRAWING: None

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal aligning film obtained from the liquid crystal aligning agent, and a liquid crystal display element having the liquid crystal aligning film.

  Currently, liquid crystal display elements are widely used in image display portions of many devices such as digital cameras, personal computers, portable terminals, and televisions. Such a liquid crystal display element has a structure in which a liquid crystal composition having fluidity is sandwiched and sealed between two support substrates, and a liquid crystal alignment for aligning liquid crystal molecules on the surface of the substrate in contact with the liquid crystal. A membrane is provided. The liquid crystal alignment film is generally produced through a step of applying a liquid crystal aligning agent on the substrate. Further, when aligning liquid crystal molecules in the in-plane direction of the substrate, a rubbing treatment, a photo-alignment treatment, or the like is performed on the coating film obtained from the liquid crystal aligning agent.

  There are various properties required for the liquid crystal alignment film. Resistance to rubbing (rubbing resistance) is one of the important characteristics. The rubbing process is known as a method of forming a liquid crystal alignment film from a polymer film formed on a substrate in the manufacturing process of a liquid crystal display element, and is still widely used industrially today.

  In this rubbing treatment, there is a known problem that dust and scratches generated by scraping the liquid crystal alignment film deteriorate the display quality of the display element. Therefore, the liquid crystal alignment film is required to have high rubbing resistance with little dust and damage to the liquid crystal alignment film caused by the rubbing treatment. For example, Patent Documents 1 and 2 disclose a liquid crystal aligning agent for the purpose of providing a liquid crystal alignment film that is less likely to be scraped or damaged by rubbing. In addition to the rubbing resistance of the liquid crystal alignment film, Patent Document 3 discloses a liquid crystal alignment agent for the purpose of providing a highly reliable liquid crystal alignment film having a high voltage holding ratio and a low ion density even at high temperatures. It is disclosed.

JP 2008-203332 A International Publication No. 2010/053128 International Publication No. 2010/050523

  With the recent high performance of liquid crystal display elements, liquid crystal alignment films are required to realize various characteristics at a higher level than before. For example, as the liquid crystal display element has been improved in definition, a liquid crystal alignment film that requires less rubbing and damage of the coating film as compared with the related art has been required for rubbing resistance. In view of the above, an object of the present invention is to provide a liquid crystal alignment film and a liquid crystal aligning agent excellent in rubbing resistance.

As a result of repeated studies, the present inventors have completed the present invention. Specifically, the gist of the present invention is as follows.
[1] Diamine having at least one partial structure (p) selected from a methacryl group, an acryl group, a vinyl group, a substituted vinyl group substituted with a hydrocarbon group having 1 to 12 carbon atoms and a cinnamoyl group in the side chain ( The liquid crystal aligning agent containing the polymer (P) synthesize | combined using the diamine component containing I) and diamine (II) which has the partial structure represented by following formula (H).

In the formula (H), R ₁ is an amino-protecting group. Two “* 1” s are bonded to a hydrocarbon group or a hydrogen atom, and at least one is a bond bonded to the hydrocarbon group.

  The liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention is excellent in rubbing resistance, and the liquid crystal display element provided with the liquid crystal alignment film can provide a high-performance liquid crystal display element.

  The liquid crystal aligning agent of the present invention has at least one partial structure (p) selected from a methacryl group, an acryl group, a vinyl group, a substituted vinyl group substituted with a hydrocarbon group having 1 to 12 carbon atoms, and a cinnamoyl group. It contains a polymer (P) synthesized using a diamine component containing a diamine (I) in a chain and a diamine (II) having a partial structure represented by the following formula (H), and an organic solvent. . Hereinafter, the present invention will be described in detail.

R ₁ is an amino-protecting group. Two “* 1” bonds to a hydrocarbon group or a hydrogen atom, and at least one of them represents a bond bonded to the hydrocarbon group.
<Diamine (I)>
The diamine (I) used in the present invention is at least one partial structure selected from a methacryl group, an acrylic group, a vinyl group, a substituted vinyl group substituted with a hydrocarbon group having 1 to 12 carbon atoms, and a cinnamoyl group (p ) In the side chain.

  The partial structure (p) is more preferably at least one selected from a methacryl group, an acrylic group, a vinyl group, and a substituted vinyl group substituted with a hydrocarbon group having 1 to 12 carbon atoms. ) To (1-4) are more preferable.

In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom, a linear hydrocarbon group having 1 to 12 carbon atoms, or a branched hydrocarbon group having 1 to 12 carbon atoms. R ³ and R ⁴ each independently represents a hydrogen atom or a methyl group. “* 1” indicates a bond.

Examples of the linear hydrocarbon group for R ² in the formula (1-2) include an alkyl group and an alkenyl group, and an alkyl group is more preferable. More preferably, it is a C1-C3 alkyl group, and a methyl group is more preferable.

Examples of the branched hydrocarbon group for R ² in the formula (1-2) include a branched alkyl group and a branched alkenyl group, and a branched alkyl group is preferable. A branched alkyl group having 3 to 4 carbon atoms is more preferable, and an i-propyl group, a 2-methylpropyl group, and a 1-methylpropyl group are more preferable.

  Examples of the side chain having the partial structure (p) include those represented by the following formula (b).

R ⁸ is a single bond or —CH ₂ —, —O—, —COO—, —OCO—, —NHCO—, —CONH—, —NH—, —NHC (═O) NH—, —CH ₂ O—. , —N (R ^a ) — (R ^a represents a linear hydrocarbon group having 1 to 12 carbon atoms or a branched hydrocarbon group having 1 to 12 carbon atoms), —CON (CH ₃ )-, -N (CH ₃ ) CO-, and R ⁹ represents a single bond or an alkylene group having 1 to 20 carbon atoms which is unsubstituted or substituted by a fluorine atom. In the group, at least one —CH ₂ CH ₂ — may be replaced with —CH═CH—, and at least one —CH ₂ — may be replaced with —CF ₂ —. Are not replaced by these groups. At best; -O -, - COO -, - OCO -, - NHCO -, - CONH -, - NH-, a divalent carbocyclic, divalent ^{heterocyclic; R 10} is the partial structure (p) "* 1" represents a bond bonded to the main chain of the polymer.

R ⁸ can be formed by a general organic synthetic method, but from the viewpoint of ease of synthesis, —CH ₂ —, —O—, —COO—, —NHCO—, —NH—, —CH ₂ O—, -N (R ^<a> )-(R ^<a> represents a C1-C12 linear hydrocarbon group or a C1-C12 branched hydrocarbon group) is preferable.

Specific examples of the divalent carbocycle or divalent heterocycle that replaces any —CH ₂ — in R ⁹ include cyclohexane, benzene, naphthalene, bicyclohexane, cyclohexylbenzene, biphenyl, 4-cyclohexylbiphenyl, gonane, Examples include, but are not limited to, groups in which two hydrogen atoms are removed from a compound such as pyridine, pyrrole, pyrimidine, thiophene, furan, carbazole, oxazole, and 1,3,5-triazine.

R ¹⁰ is the partial structure (p), and the preferred range is also as described above.

  Examples of the diamine (I) having the partial structure (p) in the side chain include, but are not limited to, the following compound (1-D).

Sp represents a single bond, —O— or —O—Q _T —O— (wherein Q _T represents a divalent group containing a phenylene group or a naphthalene group), and m is 0 or 1. R ^{8, R 9, R 10} has the same meaning as ^{R 8,} R ^{9, R 10} in the formula (b).

  Preferred embodiments of the diamine (I) having the partial structure (p) in the side chain include the following compounds (1-D1) to (1-D4).

Definition of ^R 8, ^{R 9} and ^{R 10} in the formula has the same meaning as ^R 8, ^{R 9} and ^{R 10} in the formula (b).
As the diamine (I), the following formulas (1-D1-1) to (1-D1-7) are more preferable.

In the formula, X ¹ and X ² are each independently a single bond or a linking group selected from —O—, —COO—, —NHCO—, and —NH—, and Y is unsubstituted or substituted by a fluorine atom. A C1-C20 alkylene group is represented, R ^<a> , R ^<b> , R ^<c> is synonymous with R < ² >, R < ³ >, R < ⁴ > in said Formula (1-2), respectively. R ^d represents a linear hydrocarbon group having 1 to 12 carbon atoms or a branched hydrocarbon group having 1 to 12 carbon atoms.
In the formula (1-D1-1), the following formula (1-D1-9) is more preferable.

(In the formula (1-D1-9), n is an integer of 1 to 20, and R ¹ represents a hydrogen atom or a methyl group.)
The diamine (I) is more preferably the formula (1-D1-5) or (1-D1-9).
Since the diamine component containing the above formulas (1-D1-5) to (1-D1-9) has high flexibility of the monomer, the crosslinking reaction is likely to proceed, and the degree of crosslinking of the liquid crystal alignment film can be further improved. it can.

In the formula (1-D1-5), R ^a preferably has 6 or less carbon atoms, more preferably 3 or less, and particularly preferably R ^a is a hydrogen atom.

In the formula (1-D1-5), R ^b and R ^c are preferably hydrogen atoms.

In the above formula (1-D1-5), R ^d is preferably a linear hydrocarbon group having 6 or less carbon atoms or a branched hydrocarbon group, and more preferably a linear hydrocarbon group having 3 or less carbon atoms. It is a hydrocarbon group or a branched hydrocarbon group.

  In the formula (1-D1-5), the preferred positions of the two amino groups are 2, 4 positions, 2, 5 positions, or 3, 5 positions on the benzene ring with respect to the N-allyl group. It is.

  Specific examples of the diamine having the structure represented by the above formula (1-D1-5) are shown in the following formulas (1-D1-5b) to (1-D1-5g), but are not limited thereto.

  Among the diamines, the formula (1-D1-5b) or the formula (1-D1-5c) is preferable.

  N in the formula (1-D1-9) is preferably an integer of 1 to 10. Specific examples represented by the above formula (1-D1-9) are shown in the following formulas (1-D1-9a) to (1-D1-9b), but are not limited thereto.

In addition, the said diamine (I) can be used individually by 1 type in these or in combination of 2 or more types.
<Diamine (II)>
The diamine (II) used in the present invention has a partial structure represented by the following formula (H).

In the formula, R ₁ is an amino-protecting group. Two “* 1” s are bonded to a hydrocarbon group or a hydrogen atom, and at least one is a bond bonded to the hydrocarbon group.

R ¹ is not particularly limited as long as it functions as a protecting group for an amino group, and examples thereof include a monovalent organic group that can be eliminated by at least one of heat, light, acid and base. R ¹ is preferably a monovalent organic group that is at least eliminated by heat, and specific examples thereof include carbamate-based protecting groups, amide-based protecting groups, imide-based protecting groups, sulfonamide-based protecting groups, and the like. It is done.

R ¹ is preferably a carbamate-based protecting group from the viewpoint of high heat detachability. Specific examples thereof include tert-butoxycarbonyl group, benzyloxycarbonyl group, 1,1-dimethyl-2-haloethyloxycarbonyl group, 1,1-dimethyl-2-cyanoethyloxycarbonyl group, 9-fluorenyl. Examples thereof include a methyloxycarbonyl group, an allyloxycarbonyl group, and a 2- (trimethylsilyl) ethoxycarbonyl group. Among these, a tert-butoxycarbonyl group (BOC group) is preferable.

  The hydrocarbon group to which the bond “* 1” in the formula is bonded may be a chain hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group.

  As the diamine (II), diamines represented by the following formulas (2-D1) to (2-D3) are preferable.

A ¹ and A ⁵ are each independently a single bond and an alkylene group having 1 to 5 carbon atoms, A ² and A ⁴ are each independently an alkylene group having 1 to 5 carbon atoms, and B ¹ And B ² are each independently a single bond, —O—, —NH—, —N (CH ₃ ) —, —C (═O) —, —C (═O) O—, —C (═O ) NH—, —C (═O) N (CH ₃ ) —, —OC (═O) —, —NHC (═O) —, or —N (CH ₃ ) C (═O) — Represents a divalent nitrogen-containing heterocyclic compound, n is an integer of 2 to 8,
C ¹ is — (CH ₂ ) —, —O—, —S—, —NH—;
C ² is —O—, —C (═O) NH—, —NHC (═O) —, —OC (═O) —, —C (═O) O—, —NH (═CO) NH—. , -NH-, -C (= O)-,
D ₁ is an amino-protecting group;
E ₁ is an aromatic hydrocarbon group having 6 to 12 carbon atoms, an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an alkynylene group having 2 to 6 carbon atoms.

In the formulas (2-D1) to (2-D3), examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetotamethylene group, a pentamethylene group, and a hexamethylene group. D ₁ has the same meaning as R ₁ in formula (H).

In the formula (2-D1), examples of the divalent nitrogen-containing heterocyclic compound include groups in which two hydrogen atoms have been removed from an aliphatic heterocyclic ring such as azetidine, pyrrolidine, piperidine, or hexamethyleneimine. it can. Binding position of the amino group in the benzene ring is not limited, each amino group, 3-position to the nitrogen atom of the nitrogen-containing heterocyclic compound, or 4-position, relative to the nitrogen atom to which A2 and D ₁ is attached 3-position, or, preferably in the 4-position, 4-position to the nitrogen atom of the nitrogen-containing heterocyclic compound, that is in the 4-position to the nitrogen atom to which A2 and D ₁ is attached More preferred.

  Preferable examples of the formula (2-D2) include two structures represented by formulas (1-1) to (1-21) described in paragraphs [0031] to [0032] of International Publication No. 2015/060360. Examples include a structure in which an amino group is bonded.

  In the formula (2-D3), examples of the alkenylene group having 2 to 6 carbon atoms include vinylene group, 1-propenylene group, 2-propenylene group, 1-butenylene group, 2-butenylene group, 1-pentenylene group, 2- Examples include a pentenylene group, a 1-hexenylene group, and a 2-hexenylene group. Examples of the alkynylene group having 2 to 6 carbon atoms include an ethynylene group, a propynylene group, a butynylene group, a pentynylene group, and a hexynylene group.

  In the formula (2-D3), the aromatic hydrocarbon group having 6 to 12 carbon atoms is, for example, a phenylene group, a biphenylene group, or a naphthylene group, and most preferably a phenylene group.

  The diamine (II) is more preferably a diamine selected from the following formulas (2-D1-1) to (2-D3-1).

In the formula, Q ₁ represents an alkylene group having 1 to 5 carbon atoms, E ₁ represents an alkylene group having 1 to 4 carbon atoms or a phenylene group, and Boc represents a tert-butoxycarbonyl group.

  Preferred structures of the diamine (II) include structures represented by the above formula (2-D2-1) and the following formulas (2-Da) to (2-Dc).

In the formula, Boc represents a tert-butoxycarbonyl group.
The diamine (II) can be used alone or in combination of two or more.
<Other diamines>
The diamine component used for the synthesis of the polymer (P) may include a diamine other than the diamine (I) and the diamine (II) (hereinafter referred to as other diamine). Specific examples thereof include a diamine having a urea group represented by the formula (2) described in paragraphs [0036] to [0037] of International Publication No. 2013/008906, 3,5-diaminobenzoic acid, 2,4- Diaminobenzoic acid, 2,5-diaminobenzoic acid, 4,4′-diaminobiphenyl-3-carboxylic acid, 4,4′-diaminodiphenylmethane-3-carboxylic acid, 4,4′-diaminodiphenylethane-3-carboxylic acid Acid, 4,4′-diaminobiphenyl-3,3′-dicarboxylic acid, 4,4′-diaminobiphenyl-2,2′-dicarboxylic acid, 3,3′-diaminobiphenyl-4,4′-dicarboxylic acid, 3,3′-diaminobiphenyl-2,4′-dicarboxylic acid, 4,4′-diaminodiphenylmethane-3,3′-dicarboxylic acid, 4,4′-diaminodiphenyl ether-3, Diamine containing a carboxyl group such as' -dicarboxylic acid, diaminoorganosiloxane such as 1,3-bis (3-aminopropyl) -tetramethyldisiloxane, paragraphs [0009] to [0010] of International Publication No. 2008/078796 N-substituted diamine represented by the formula (1) of formula (1), nitrogen content represented by formulas (-1-2) to (N-1-8) described in paragraph [0025] of JP-A-2016-200798 A diamine having a structure, a diamine having a pyridine ring, such as diamines (B1) to (B12) described in paragraphs [0135] to [0137] of International Publication No. 2010/035719, and paragraph [0022] of International Publication No. 2015/122413 Diamines represented by formulas (2-1), (2-3), (2-4), (2-7) and (2-9) described in Although such diamines represented by the formula (D-0) and the like are not limited thereto.

  In the formula, Y is the formulas (Y-1) to (Y-36), (Y-39) to (Y-60) described in paragraphs [0026] to [0039] of International Publication No. 2015/119168, The divalent organic group represented by the structure of (Y-62)-(Y-97), (Y-101)-(Y-110), (Y-112)-(Y-119) is represented.

  As preferred structures of other diamines, the following formulas (YB-1) to (YB-18) can be exemplified.

  Among the above, (YB-12) is particularly preferable from the viewpoint of further improving rubbing resistance, and (YB-1) to (YB-3) are particularly preferable from the viewpoint of further improving liquid crystal alignment. The said other diamine can be used selecting 1 type (s) or 2 or more types suitably.

  The diamine component used in the polymer (P) of the present invention preferably contains the diamine (I) and the diamine (II), and the total amount of the diamine (I) and the diamine (II) is the diamine component. 10-100 mol% is more preferable with respect to the whole.

  Further, it is more preferable that the diamine (I) is contained in an amount of 20 mol% to 60 mol% and the diamine (II) is contained in an amount of 40 to 80 mol% based on the entire diamine component.

By using the liquid crystal aligning agent containing the polymer (P), the protective group of the partial structure represented by the above formula (H) is eliminated during the firing of the liquid crystal aligning agent, and an amino group showing crosslinkability is generated. And form a cross-linked structure with the partial structure (p). By such an action, the film density of the polymer (P) is improved, and a liquid crystal alignment film having excellent rubbing resistance can be obtained.
<Polymer (P)>
The polymer (P) contained in the liquid crystal aligning agent according to the present invention is a polymer synthesized using the diamine component.

  Examples of such a polymer include polyamides synthesized from diamine compounds and dicarboxylic acid compounds; polyureas synthesized from diamine compounds and diisocyanate compounds; polyamic acids synthesized from diamine compounds and tetracarboxylic dianhydrides; A polyamic acid ester obtained by esterifying a carboxyl group of a polyamic acid or synthesized from a diamine compound and a tetracarboxylic acid diester compound; a polyimide obtained by imidizing the above polyamic acid or polyamic acid ester; It is done.

The main skeleton of the polymer (P) is preferably at least one selected from the group consisting of a polyamic acid, a polyamic acid ester, and a polyimide from the viewpoint that the rubbing resistance of the liquid crystal alignment film is high. From the viewpoint of high polymerization reactivity, a polyamic acid obtained by reacting a diamine component containing the diamine (I) and the diamine (II) with a tetracarboxylic acid derivative component, a polyamic acid ester, and an imidized product thereof. More preferably, it is at least one polymer of a certain polyimide,
At least a polymer comprising a polyamic acid obtained by reacting a diamine component containing the diamine (I) and the diamine (II) and a tetracarboxylic acid derivative component, a polyamic acid ester, and a polyimide which is an imidized product thereof. One type is more preferable. Examples of the tetracarboxylic acid component include tetracarboxylic dianhydride, tetracarboxylic acid diester, and tetracarboxylic acid diester dihalide.
<Polyamic acid>
The polyamic acid as the polymer (P) can be obtained, for example, by reacting tetracarboxylic dianhydride with diamine. Examples of the tetracarboxylic dianhydride include compounds represented by the following formula (C-0).

  X is a tetravalent organic group, and if it shows a specific example, the structure shown by (X-1)-(X-46) as described in paragraph [0042]-[0045] of international publication gazette WO2015 / 119168. Is mentioned.

  Although preferable X is shown to following formula (A-1)-(A-21) below, it is not limited to these.

As said Formula (C-0), X is represented by Formula (A-1)-(A-8), (A-13)-(A-14), (A-15), (A-17). The tetravalent organic group is particularly preferable from the viewpoint of further improving the rubbing resistance. As the tetracarboxylic dianhydride used for the synthesis of the polyamic acid, at least one compound of the above preferred tetracarboxylic dianhydrides is used with respect to the total amount of the tetracarboxylic dianhydrides used for the synthesis. What contains 20 mol% or more is preferable, and what contains 40 mol% or more is more preferable.
The ratio of the tetracarboxylic dianhydride and the diamine used in the polyamic acid synthesis reaction is 0.2 to 2 for the tetracarboxylic dianhydride acid anhydride group to 1 equivalent of the amino group of the diamine. The ratio which becomes an equivalent is preferable, and the ratio which becomes 0.3-1.2 equivalent is more preferable.
Moreover, you may make it react with a molecular weight modifier as needed. Examples of the molecular weight modifier include acid monoanhydrides such as maleic anhydride, phthalic anhydride and itaconic anhydride, monoamine compounds such as aniline, cyclohexylamine and n-butylamine, and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. Can be mentioned.

  The polyamic acid synthesis reaction is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20 ° C to 150 ° C, more preferably 0 to 100 ° C.

The organic solvent used for the reaction is not particularly limited as long as the produced polyamic acid dissolves. Specific examples include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol and halogen. It is preferable to use one or more selected from the group consisting of fluorinated phenols as a solvent, or to use a mixture of one or more of these and another organic solvent.
<Polyamic acid ester>
The polyamic acid ester as the polymer (P) is, for example, [I] a known method of reacting the polyamic acid obtained by the above synthesis reaction with an esterifying agent, or [II] reacting a tetracarboxylic acid diester with a diamine. Or a known method of reacting [III] tetracarboxylic acid diester dihalide with a diamine. In this specification, “tetracarboxylic acid diester” means a compound in which two of the four carboxyl groups of tetracarboxylic acid are esterified and the remaining two are carboxyl groups. “Tetracarboxylic acid diester dihalide” means a compound in which two of the four carboxyl groups of tetracarboxylic acid are esterified and the remaining two are halogenated.

  As a preferable structure of the tetracarboxylic acid diester used in the above [II], the structures shown in the formulas (A-1) to (A-93) described in paragraphs [0021] to [0033] of International Publication No. 2013/031857 are shown. Can be mentioned.

  As a preferable structure of the tetracarboxylic acid diester dihalide used in the above [III], there can be mentioned the structures described in paragraphs [0050] to [0051] of International Publication No. 2010/092989.

The polyamic acid ester contained in the liquid crystal aligning agent may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist.
<Polyimide>
The polyimide as the polymer (P) can be obtained by dehydrating and ring-closing and imidizing the polyamic acid synthesized as described above. Polyimide may be a completely imidized product obtained by dehydrating and ring-closing all of the amic acid structure of the polyamic acid that is the precursor, and only a part of the amic acid structure is dehydrating and ring-closing to form an amic acid structure and an imide ring. It may be a partially imidized product having a coexisting structure. The polyimide preferably has an imidation ratio of 20% or more, more preferably 30 to 90%, and even more preferably 40 to 80% from the viewpoint of high solubility of the polymer. This imidation ratio represents the ratio of the number of imide ring structures to the total of the number of polyimide amic acid structures and the number of imide ring structures in percentage. Here, a part of the imide ring may be an isoimide ring.

  Dehydration ring closure is performed by a method in which polyamic acid is dissolved in an organic solvent, a dehydrating agent and a dehydration ring closure catalyst are added to the solution, and heating is performed as necessary. In the method of adding a dehydrating agent and a dehydrating ring-closing catalyst to a polyamic acid solution, as the dehydrating agent, for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, triethylamine and the like can be used. Examples of the organic solvent used in the dehydration ring-closing reaction include the organic solvents exemplified as those used for the synthesis of polyamic acid.

  In this way, a reaction solution containing polyimide is obtained. In addition, the synthesis | combining method of a polyimide is not limited above, For example, you may carry out by imidation of polyamic acid ester.

  The polymer (P) preferably has a solution viscosity of 10 to 800 mPa · s when it is made into a solution having a concentration of 12% by mass, and has a solution viscosity of 15 to 500 mPa · s. It is more preferable. The solution viscosity (mPa · s) of the polymer is a value measured at 25 ° C. using an E-type rotational viscometer.

The molecular weight of the polymer (P) is preferably a polystyrene-converted weight average molecular weight (Mw) measured by gel permeation chromatography (GPC), and is preferably 500 to 100,000, and preferably 1,000 to 50,000. It is more preferable that Further, the molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the number average molecular weight (Mn) is preferably 15 or less, more preferably 10 or less. It exists in the point which ensures the favorable orientation and stability of a liquid crystal display element because it exists in such a molecular weight range.
<Other ingredients>
The liquid crystal aligning agent of this invention may contain components other than a polymer (P) and an organic solvent as needed. For example, polymers other than the polymer (P), crosslinkable compounds, functional silane compounds, surfactants and the like can be mentioned.

  A polymer other than the polymer (P) can be used for the purpose of improving the solution characteristics of the liquid crystal aligning agent and the electrical characteristics of the liquid crystal alignment film, or imparting photoalignment to the liquid crystal alignment film. Examples of such polymers include polyamic acid, polyimide, polyamic acid ester, polyorganosiloxane, polyester, polyamide, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate, and the like. .

  When a polymer other than the polymer (P) is added to the liquid crystal aligning agent, the blending ratio is preferably 70 parts by mass or less with respect to 100 parts by mass of the total polymer components in the composition, 0.1 to 60 Mass parts are more preferred, and 0.1 to 40 parts by mass are even more preferred.

  The crosslinkable compound can be used for the purpose of increasing the strength of the liquid crystal alignment film. Examples of the crosslinkable compound include compounds having an epoxy group, an isocyanate group, an oxetane group, or a cyclocarbonate group described in paragraphs [0109] to [0113] of International Publication WO2016 / 047771, or a hydroxy group or a hydroxyalkyl group. In addition to a compound having at least one group selected from the group consisting of a group and a lower alkoxyalkyl group, a compound having a blocked isocyanate group and the like can be mentioned.

  The block isocyanate compound is available as a commercial product. For example, Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (above, manufactured by Nippon Polyurethane Industry Co., Ltd.), Takenate B -830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (manufactured by Mitsui Chemicals, Inc.) and the like can be preferably used.

  The above is an example of a crosslinkable compound, but is not limited thereto. Moreover, the crosslinkable compound used for the liquid crystal aligning agent of this invention may be 1 type, or may be combined 2 or more types.

  The content of the other crosslinkable compound in the liquid crystal aligning agent of the present invention is 0.1 to 150 parts by mass, 0.1 to 100 parts by mass, or 1 to 100 parts by mass of all polymer components. 50 parts by mass.

  The functional silane compound can be used for the purpose of improving the adhesion between the liquid crystal alignment film and the base substrate. Specific examples thereof include silane compounds described in paragraph [0019] of International Publication No. 2014/119682. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of all the polymer components.

  The surfactant can be used for the purpose of improving the film thickness uniformity and surface smoothness of the liquid crystal alignment film. Examples of the compound include a fluorine-based surfactant, a silicone-based surfactant, and a nonionic surfactant. Specific examples of these include surfactants described in paragraph [0117] of International Publication No. WO2016 / 047771. The amount of the surfactant used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of all the polymer components contained in the liquid crystal aligning agent.

  Furthermore, in the liquid crystal aligning agent of the present invention, as a compound that promotes charge transfer in the liquid crystal aligning film and promotes charge release of the device, the international publication WO2011 / 132751 (published 2011.10.27), 69- Nitrogen-containing heterocyclic amine compounds represented by the formulas [M1] to [M156], which are listed on page 73, can be added. The amine compound may be added directly to the liquid crystal aligning agent, but it is preferable to add the amine compound after forming a solution having a concentration of 0.1 to 10% by mass, preferably 1 to 7% by mass. The solvent is not particularly limited as long as the specific polymer (P) is dissolved.

When the liquid crystal aligning agent of the present invention contains a polyamic acid or a polyamic acid ester, an imidization accelerator or the like may be added for the purpose of efficiently proceeding imidization by heating when the coating film is baked.
<Organic solvent>
The liquid crystal aligning agent according to the present invention is prepared as a liquid composition in which the polymer (P) and other components used as necessary are dispersed or dissolved in an appropriate organic solvent.

  Examples of the organic solvent used include lactone solvents such as γ-valerolactone and γ-butyrolactone; lactam solvents such as γ-butyrolactam, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide Amide solvents such as 4-hydroxy-4-methyl-2-pentanone, 2,6-dimethyl-4-heptanone, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate , N-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol monomethyl ether, ethylene glycol ethyl ether, ethylene glycol Monobutyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, Diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monobutyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropy Glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopropyl ether, diisopentyl ether; carbonate solvents such as ethylene carbonate and propylene carbonate, 1- Examples include hexanol, cyclohexanol, 1,2-ethanediol, diisobutyl carbinol, 2,6-dimethyl-4-heptanol, and the like. These can be used alone or in admixture of two or more.

  Preferred solvent combinations include N-methyl-2-pyrrolidone and 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, diethylene glycol diethyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and 2 , 6-Dimethyl-4-heptanone, N-methyl-2-pyrrolidone and γ-butyrolactone, propylene glycol monobutyl ether and diisopropyl ether, N-methyl-2-pyrrolidone and γ Butyrolactone and propylene glycol monobutyl ether and 2,6-dimethyl-4-heptanol, N- methyl-2-pyrrolidone and γ- butyrolactone and dipropylene glycol dimethyl ether, and the like. The kind and content of such a solvent are appropriately selected according to the application device, application conditions, application environment, and the like of the liquid crystal aligning agent.

  The solid content concentration in the liquid crystal aligning agent (the ratio of the total mass of components other than the organic solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc. Is in the range of 1-10% by weight.

The particularly preferable range of the solid content concentration varies depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, when the spinner method is used, the solid content concentration is particularly preferably in the range of 1.5 to 4.5% by mass. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by mass, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the inkjet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by mass, and thereby the solution viscosity is in the range of 3 to 15 mPa · s.
<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal alignment film according to the present invention is formed by the liquid crystal aligning agent prepared as described above. Moreover, the liquid crystal display element which concerns on this invention comprises the liquid crystal aligning film formed using the said liquid crystal aligning agent. The driving mode of the liquid crystal display element is not particularly limited, and various operation modes such as TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS type, FFS type, OCB type, etc. Applicable to.

A liquid crystal display element can be manufactured by the process including the following processes (1-1)-(1-3), for example. In the step (1-1), a substrate to be used is different depending on a desired operation mode. Step (1-2) and step (1-3) are common to each operation mode.
[Step (1-1): Formation of coating film]
First, a liquid crystal aligning agent is apply | coated on a board | substrate, Then, a coating film is formed on a board | substrate by heating an application surface.
(1-1A) When manufacturing a TN-type, STN-type, or VA-type liquid crystal display element, for example, first, a pair of two substrates on which patterned transparent conductive films are provided, and each transparent conductive film is formed. A liquid crystal aligning agent is preferably applied on the surface by an offset printing method, a spin coating method, a roll coater method or an ink jet printing method, respectively.

As the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly (cycloaliphatic olefin) can be used.
As a transparent conductive film provided on one surface of the substrate, an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), etc. Can be used.

After applying the liquid crystal aligning agent, preheating (pre-baking) is preferably performed for the purpose of preventing dripping of the applied liquid crystal aligning agent. The pre-baking temperature is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 40 to 100 ° C. Thereafter, a firing (post-baking) step is performed for the purpose of completely removing the solvent. The firing temperature (post-bake temperature) at this time is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The post-bake time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The thickness of the film thus formed is preferably 1 to 1000 nm, more preferably 5 to 500 nm.
(1-1B) When manufacturing an IPS type or FFS type liquid crystal display element, an electrode forming surface of a substrate provided with an electrode made of a transparent conductive film or a metal film patterned in a comb shape, and an electrode are provided. A liquid crystal aligning agent is apply | coated to one surface of the counter substrate which is not formed, respectively, Then, each coating surface is heated, and a coating film is formed. As the metal film, for example, a film made of a metal such as chromium can be used.
[Step (1-2): Orientation ability imparting treatment]
When manufacturing a TN type, STN type, IPS type, or FFS type liquid crystal display element, the process which provides liquid crystal aligning ability to the coating film formed at the said process (1-1) is implemented. Examples of the orientation-imparting treatment include rubbing treatment in which the coating film is rubbed in a fixed direction with a roll wound with a cloth made of fibers such as nylon, rayon, and cotton, and photo-alignment in which the coating film is irradiated with polarized or non-polarized radiation. Processing. On the other hand, when manufacturing a VA type liquid crystal display element, the coating film formed in the step (1-1) can be used as it is as a liquid crystal alignment film, but the coating film may be subjected to alignment ability imparting treatment. .

  In the photo-alignment treatment, ultraviolet rays and visible rays including light having a wavelength of 150 to 800 nm can be used as the radiation applied to the coating film, for example. When the radiation is polarized light, it may be linearly polarized light or partially polarized light. When the radiation used is linearly polarized light or partially polarized light, irradiation may be performed from a direction perpendicular to the substrate surface, an oblique direction, or a combination thereof. When non-polarized radiation is irradiated, the irradiation direction is an oblique direction.

As a light source to be 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, an LED lamp, or the like can be used. Ultraviolet rays in a preferable wavelength region can be obtained by means of using a light source in combination with, for example, a filter or a diffraction grating. The radiation dose is preferably 100 to 50,000 J / m ² , more preferably 300 to 20,000 J / m ² .
Moreover, you may perform light irradiation with respect to a coating film, heating a coating film, in order to improve the reactivity. The temperature at the time of heating is 30-250 degreeC normally, Preferably it is 40-200 degreeC, More preferably, it is 50-150 degreeC.

  In the photo-alignment treatment, heat treatment may be performed at the time of light irradiation, or heat treatment may be performed after the photo-alignment treatment. The heating temperature at this time is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The heating time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. Further, instead of the heat treatment, a washing treatment with an organic solvent or water may be performed, or the washing treatment and the heat treatment may be combined.

In addition to the liquid crystal alignment film after the rubbing treatment, a part of the liquid crystal alignment film is irradiated with ultraviolet rays to change the pretilt angle of a part of the liquid crystal alignment film, After the resist film is formed, a rubbing process is performed in a direction different from the previous rubbing process, and then a process of removing the resist film may be performed so that the liquid crystal alignment film has different liquid crystal alignment capabilities for each region. In this case, it is possible to improve the visibility characteristics of the obtained liquid crystal display element. A liquid crystal alignment film suitable for a VA liquid crystal display element can also be suitably used for a PSA (Polymer Sustained Alignment) type liquid crystal display element.
[Step (1-3): Construction of liquid crystal cell]
(1-3A) Two substrates on which the liquid crystal alignment film is formed as described above are prepared, and a liquid crystal cell is manufactured by disposing a liquid crystal between the two substrates facing each other. In order to manufacture a liquid crystal cell, the following two methods are mentioned, for example. In the first method, two substrates are arranged to face each other through a gap (cell gap) so that the respective liquid crystal alignment films are opposed to each other, and the peripheral portions of the two substrates are bonded together using a sealing agent. A liquid crystal cell can be manufactured by sealing the injection hole after injecting and filling the liquid crystal in the cell gap defined by the surface and the sealing agent. The second method is a method called an ODF (One Drop Fill) method. For example, an ultraviolet light curable sealant is applied to a predetermined location on one of the two substrates on which the liquid crystal alignment film is formed, and liquid crystal is dropped to a predetermined location on the liquid crystal alignment film surface. After that, the other substrate is bonded so that the liquid crystal alignment film faces, and the liquid crystal is spread over the entire surface of the substrate, and then the entire surface of the substrate is irradiated with ultraviolet light to cure the sealant, thereby manufacturing a liquid crystal cell. it can. Regardless of which method is used, the liquid crystal cell produced as described above is further heated to a temperature at which the used liquid crystal takes an isotropic phase, and then slowly cooled to room temperature, thereby removing the flow alignment at the time of filling the liquid crystal. It is desirable to do.

  As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used. Examples of the liquid crystal include nematic liquid crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferable.

(1-3B) When manufacturing a PSA type liquid crystal display element, a liquid crystal cell is constructed in the same manner as in the above (1-3A) except that a photopolymerizable compound is injected or dropped together with liquid crystal. Thereafter, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates. The voltage applied here can be, for example, 5 to 50 V direct current or alternating current. Moreover, as light to irradiate, the ultraviolet-ray containing light with a wavelength of 300-400 nm is preferable. As a light source of 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, or the like can be used. The irradiation dose of light, preferably less than 1,000 J / ^{m 2} or more 200,000 J / ^{m 2,} more preferably from 1,000~100,000J / ^{m 2.}

  (1-3C) When a coating film is formed on a substrate using a liquid crystal aligning agent containing a compound (polymer or additive) having a photopolymerizable group, a liquid crystal cell is formed in the same manner as (1-3A) above. Then, a method of manufacturing a liquid crystal display element may be adopted by performing a step of irradiating light to the liquid crystal cell in a state where a voltage is applied between the conductive films of the pair of substrates. According to this method, the merit of the PSA mode can be realized with a small amount of light irradiation. The description of (1-3B) above can be applied to the voltage to be applied and the conditions of the light to be irradiated.

  And a liquid crystal display element can be obtained by sticking a polarizing plate on the outer surface of a liquid crystal cell. As a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film itself in which a polarizing film called an “H film” in which iodine is absorbed while stretching and aligning polyvinyl alcohol is sandwiched between cellulose acetate protective films The polarizing plate which consists of can be mentioned.

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

Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
The abbreviations of the compounds used in the examples and comparative examples, and the method of property evaluation are as follows.
CA-1: pyromellitic anhydride CA-2: 1,2,3,4-cyclobutanetetracarboxylic dianhydride DA-1: compound DA-2 represented by the following structural formula (DA-1): Compound DA-3 represented by Structural Formula (DA-2): Compound DA-4 represented by Structural Formula (DA-3) below: Compound DA-5 represented by Structural Formula (DA-4) below: Compound represented by Structural Formula (DA-5)

Boc represents a tert-butoxycarbonyl group.
<Organic solvent>
NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve <Additive>
LS-4668: 3-glycidoxypropyltriethoxysilane <viscosity measurement>
In the synthesis example and the comparative synthesis example, the viscosity of the polymer is an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), a sample amount of 1.1 mL, and a cone rotor TE-1 (1 ° 34 ′, R24). Measured with
<Measurement of molecular weight of polymer>
The weight average molecular weight Mw or number average molecular weight Mn of a polymer is a polystyrene conversion value measured by GPC under the following conditions.
GPC device: manufactured by Shodex (GPC-101)
Column: manufactured by Shodex (KD-803 and KD-805)
Column temperature: 50 ° C
Eluent: N, N-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H ₂ O) 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran) (THF) is 10 ml / L)
Flow rate: 1.0 ml / min Standard sample for preparing calibration curve: TSK (Tosoh Co., Ltd.) standard polyethylene oxide (weight average molecular weight (Mw); about 900,000, 150,000, 100,000 and 30,000 ), And polyethylene glycol (Peak Top Molecular Weight (Mp); about 12,000, 4,000 and 1,000) manufactured by Polymer Laboratory.
<Synthesis of polymer>
[Synthesis Example 1]
After adding DA-1 (1.02 g, 5.0 mmol) and DA-3 (1.98 g, 5.0 mmol) as a diamine component to a 100 ml four-necked flask with a stirrer and a nitrogen inlet tube, NMP (28 g) was added and dissolved by stirring while feeding nitrogen. While stirring this solution, CA-1 (0.87 g, 4.0 mmol), CA-2 (1.18 g, 6.0 mmol) and 10 g of NMP were added as tetracarboxylic acid components, and the conditions were further increased to 50 ° C. Under stirring for 12 hours, a polyamic acid solution (PAA-A1) was obtained. The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 320 mPa · s. Moreover, the molecular weight of this polyamic acid was number average molecular weight Mn = 24096, and weight average molecular weight Mw = 73614.
[Synthesis Examples 2 to 6]
The polyamic acid solution (PAA-A2), (PAA-A3), and polyamic acid are shown in Table 1 except that the diamine compound, tetracarboxylic acid compound, and solvent are used in the same manner as in Synthesis Example 1. Solutions (PAA-B1) to (PAA-B5) were obtained. Further, Table 2 shows the viscosity and molecular weight of the obtained polyamic acid solution at a temperature of 25 ° C.

<Preparation of liquid crystal aligning agent>
[Example 1]
To the polyamic acid solution (PAA-A1) obtained in Synthesis Example 1, an NMP diluted solution of LS-4668 is added so that LS-4668 is 1% by mass with respect to the polymer component, and NMP and BCS are further added. By adding, the liquid crystal aligning agent whose total concentration of a polymer is 4.5 mass% and whose solvent composition is NMP: BCS = 75: 25 (mass ratio) was obtained.
<Evaluation of rubbing resistance>
The liquid crystal aligning agent obtained in the above example was spin-coated on a glass substrate with an ITO electrode, dried on a hot plate at 80 ° C. for 100 seconds, and then baked at 230 ° C. for 1000 seconds. A film was formed. Using a rubbing apparatus with a roll diameter of 120 mm to which a rayon cloth YA-20-R (manufactured by Yoshikawa Chemical Co., Ltd.) was attached, the coating surface was rolled at a rotational speed of 1000 rpm, a roll traveling speed of 20 mm / sec, and an indentation amount of 0.6 mm. The substrate was rubbed under the above conditions to obtain a substrate with a liquid crystal alignment film. The liquid crystal alignment film surface was observed with a real-time scanning laser microscope 1LM21D (100 times magnification) manufactured by Lasertec Corporation.
Rubbing resistance was evaluated from the average value of rubbing scratches and rubbing scraps (adhered matter) confirmed in a range of about 6.5 mm square, which is the observation field of view, at five locations randomly observed from the substrate surface. The evaluation criteria were determined as follows. The smaller the scratches and scraps, the better. There were 12 scratches and scraps and the evaluation was A.
(Evaluation criteria)
A: 20 or less scratches and scraps B: 21 to 39 scratches and scraps C: 40 or more scraps and scraps [Examples 2 to 6] and [Comparative Examples 1 to 3]
The polyamic acid solutions (PAA-A3) to (PAA-A7) and (PAA-B1) to (PAA-B3) obtained in Synthesis Examples 3 to 10 were changed to the compositions shown in Table 3 and Table 4, respectively. A liquid crystal aligning agent was obtained in the same manner as in Example 1 except that.

  In addition, each of the prepared liquid crystal aligning agents was evaluated for rubbing resistance in the same manner as in Example 1. The results are shown in Table 3.

* 1: The usage ratio (parts by mass) of each polymer with respect to 100 parts by mass of the total amount of polymer components blended in the liquid crystal aligning agent.
* 2: Indicates the additive amount (parts by mass) of additives relative to 100 parts by mass of the total amount of polymer components.
* 3: Indicates the amount of each solvent used (mass ratio) relative to the total amount of solvent.
The liquid crystal alignment films obtained from the liquid crystal alignment agents of Examples 1 to 6 had improved rubbing resistance compared to the liquid crystal alignment films obtained from the liquid crystal alignment agents of the comparative examples.

    The liquid crystal display element using the liquid crystal aligning film obtained from the liquid crystal aligning agent of this invention can be used suitably for the display element of various liquid crystal modes.

Claims (10)

A diamine (I) having at least one partial structure (p) selected from a methacryl group, an acrylic group, a vinyl group, a substituted vinyl group substituted with a hydrocarbon group having 1 to 12 carbon atoms and a cinnamoyl group in the side chain; A liquid crystal aligning agent comprising: a polymer (P) synthesized using a diamine component containing a diamine (II) having a partial structure represented by the following formula (H); and an organic solvent .

In the formula, R ₁ is an amino-protecting group. Two “* 1” s are bonded to a hydrocarbon group or a hydrogen atom, and at least one is a bond bonded to the hydrocarbon group. The liquid crystal aligning agent of Claim 1 whose partial structure (p) is at least 1 sort (s) chosen from the structure represented by following formula (1-1)-(1-4).

In the formula, R ¹ represents a hydrogen atom or a methyl group, and in formula (1-2), R ² represents a hydrogen atom, a linear hydrocarbon group having 1 to 12 carbon atoms, or a branch having 1 to 12 carbon atoms. Represents a hydrocarbon group. R ³ and R ⁴ each independently represents a hydrogen atom or a methyl group. “* 1” indicates a bond. The liquid crystal aligning agent of Claim 1 or 2 whose diamine (I) is at least 1 sort (s) chosen from following formula (1-D1-5) and (1-D1-6).

In the formula, R ^a represents a hydrogen atom, a linear hydrocarbon group having 1 to 12 carbon atoms, or a branched hydrocarbon group having 1 to 12 carbon atoms. R ^b and R ^c each independently represent a hydrogen atom or a methyl group, and R ^d represents a linear hydrocarbon group having 1 to 12 carbon atoms or a branched hydrocarbon group having 1 to 12 carbon atoms. In the formula (1-D1-6), n is an integer of 1 to 20, and R ¹ represents a hydrogen atom or a methyl group. The liquid crystal aligning agent of any one of Claim 1 to 3 whose diamine (II) is at least 1 sort (s) chosen from following formula (2-D1)-(2-D3).

In the formula, A ¹ and A ⁵ are each independently a single bond and an alkylene group having 1 to 5 carbon atoms, A ² and A ⁴ are each independently an alkylene group having 1 to 5 carbon atoms, B1 and B2 are each independently a single bond, —O—, —NH—, —N (CH ₃ ) —, —C (═O) —, —C (═O) O—, —C (= O) NH—, —C (═O) N (CH ₃ ) —, —OC (═O) —, —NHC (═O) —, or —N (CH ₃ ) C (═O) — Cy represents a divalent nitrogen-containing heterocyclic compound, n is an integer of 2 to 8,
In formula (2-D3), C ¹ is — (CH ₂ ) —, —O—, —S—, —NH—;
C ² is —O—, —C (═O) NH—, —NHC (═O) —, —OC (═O) —, —C (═O) O—, —NH (═CO) NH—. , -NH-, -C (= O)-,
D ₁ is an amino-protecting group;
E ₁ is an aromatic hydrocarbon group having 6 to 12 carbon atoms, an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an alkynylene group having 2 to 6 carbon atoms. The liquid crystal aligning agent of Claim 4 whose diamine (II) is at least 1 sort (s) chosen from following formula (2-D1-1)-a formula (2-D3-1).

In the formula, Q ₁ represents an alkylene group having 1 to 5 carbon atoms, E ₁ represents an alkylene group having 1 to 4 carbon atoms or a phenylene group, and Boc represents a tert-butoxycarbonyl group. The liquid crystal aligning agent of any one of Claims 1-5 whose total amount of diamine (I) and diamine (II) is 10-100 mol% with respect to the whole diamine component. The diamine component contains 20 to 60 mol% of the diamine (I) with respect to the entire diamine component, and contains 40 to 80 mol% of the diamine (II). Liquid crystal aligning agent as described in. The liquid crystal aligning agent of any one of Claims 1-7 whose polymer (P) is at least 1 sort (s) chosen from a polyamic acid, polyamic acid ester, and a polyimide. The liquid crystal aligning film formed using the liquid crystal aligning agent of any one of Claims 1-8. A liquid crystal display device comprising the liquid crystal alignment film according to claim 9.