Liquid crystal alignment agent, liquid crystal alignment film, manufacturing method of liquid crystal display element, and liquid crystal display element

Abstract

A liquid crystal alignment agent, characterized in that it contains the following components (A) and (B). Component (A): polyamic acid (A) as a reaction product of a tetracarboxylic acid derivative component and a diamine component, wherein the tetracarboxylic acid derivative component comprises 100 mol% of an aromatic tetracarboxylic acid dianhydride of all the tetracarboxylic acid derivative components, and the diamine component comprises the following formula (d AL The diamine is shown in (B). Component (B): Polyamic acid (B) as a reaction product of the following tetracarboxylic acid derivative component and the following diamine component, wherein the tetracarboxylic acid derivative component comprises at least 5 mol% of at least one tetracarboxylic acid dianhydride selected from the group consisting of acyclic aliphatic tetracarboxylic acid dianhydrides and alicyclic tetracarboxylic acid dianhydrides, and the diamine component comprises the following formula (d AL The diamine shown in the figure and the following formula (d) n The diamine shown is ).

Description

Technical Field

[0001] This invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, a method for manufacturing a liquid crystal display element, and the liquid crystal display element itself. Background Technology

[0002] In liquid crystal display elements used in LCD TVs, navigation devices, smartphones, etc., a liquid crystal alignment film, used to control the alignment state of the liquid crystals, is typically disposed within the element. The liquid crystal alignment film functions to control the orientation of liquid crystal molecules in a specific direction within the liquid crystal display element. For example, a liquid crystal display element has the following structure: liquid crystal molecules, forming a liquid crystal layer, are sandwiched between liquid crystal alignment films formed on the respective surfaces of a pair of substrates. Here, the liquid crystal molecules align in a specific direction according to the liquid crystal alignment film, and respond by applying a voltage to an electrode disposed between the substrate and the liquid crystal alignment film. As a result, the liquid crystal display element displays a desired image by utilizing the orientation change caused by the response of the liquid crystal molecules. Currently, polyimide-based liquid crystal alignment films are mainly used, which are formed by coating a liquid crystal alignment agent, with polyimide precursors such as polyamide acid and a solution of soluble polyimide as the main components, onto a glass substrate or the like, and then firing them.

[0003] In recent years, with the increasing performance of liquid crystal display elements, in addition to applications such as large-screen and high-definition LCD TVs, liquid crystal display elements are also used in automotive applications (e.g., car navigation systems, dashboards), surveillance cameras, and monitoring devices for medical cameras. Considering the requirements of viewing angle characteristics, transverse electric field methods such as IPS (In-Plane Switching) and FFS (Fringe Field Switching) have been studied (Patent Document 1, Patent Document 2).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2019-082975

[0007] Patent Document 2: International Publication No. 2020-116585 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In liquid crystal alignment films used in IPS and FFS driving liquid crystal display elements, alignment restraint forces are required to suppress image retention (hereinafter also referred to as AC image retention) caused by long-term AC driving. In the rapidly evolving and increasingly sophisticated liquid crystal display elements, high display quality is highly valued, and specifications for display defects such as "image retention" are becoming increasingly stringent.

[0010] Furthermore, in liquid crystal display elements used for the aforementioned purposes, a lower pretilt angle is required than before due to viewing angle characteristics. In Patent Document 1, after obtaining polyimide from polyamic acid, a liquid crystal alignment agent containing the polyimide is used to prepare a liquid crystal alignment film. However, the preparation of the liquid crystal alignment agent involves many steps, resulting in high cost.

[0011] On the other hand, Patent Document 2 describes a liquid crystal alignment film obtained from a liquid crystal alignment agent containing two types of polyamic acids as having high resistance to AC image retention. However, after research, the inventors have determined that the effect of reducing the pretilt angle in this liquid crystal alignment film is not sufficient.

[0012] In view of the above-mentioned problems, the present invention aims to provide a liquid crystal alignment agent with excellent cost performance, a liquid crystal alignment film formed using the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film, wherein the liquid crystal alignment agent can produce a liquid crystal alignment film with excellent resistance to AC image retention and low pretilt angle characteristics.

[0013] Solution for solving the problem

[0014] In order to solve the above-mentioned technical problems, the inventors conducted in-depth research and found that forming a liquid crystal alignment film by using a liquid crystal alignment agent containing a specific polymer component is effective in achieving the above-mentioned objectives, thus completing the present invention.

[0015] Based on the aforementioned insights, this invention is based on the following main points.

[0016] A liquid crystal alignment agent, characterized in that it contains the following components (A) and (B).

[0017] (A) Component: Polyamic acid (A) as the reaction product of the following tetracarboxylic acid derivative component and the following diamine component, wherein the tetracarboxylic acid derivative component comprises 100 mol% of aromatic tetracarboxylic acid dianhydride of all the tetracarboxylic acid derivative components, and the diamine component comprises the following formula (d AL The diamine shown is ).

[0018] (B) Component: Polyamic acid (B) as the reaction product of the following tetracarboxylic acid derivative component and the following diamine component, wherein the tetracarboxylic acid derivative component comprises at least 5 mol% of at least one tetracarboxylic acid dianhydride selected from the group consisting of acyclic aliphatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides, and the diamine component comprises the following formula (d AL The diamine shown in the figure and the following formula (d) n The diamine shown is ).

[0019]

[0020] (Formula (d) AL In this context, A represents the group "*". 11 -(CH2) n -O-* 12 (*) 11 This refers to a bond bonded to an oxygen atom or a bond bonded to a carbon atom that makes up the benzene ring. 12 This indicates a bonded bond. (n is an integer from 1 to 5) is a divalent organic group. Any hydrogen atom of the aforementioned benzene ring bonded to the NH₂ group may optionally be replaced by a monovalent group.

[0021] H2N—Y—NH2 (d n )

[0022] (Formula (d) n In this context, Y represents a heterocycle or group selected from nitrogen atoms. 21 -NR-* 22 (*) 21 and* 22 This indicates a bond bonded to a carbon atom constituting an aromatic ring. This carbon atom does not form a ring with the nitrogen atom bonded to R. R represents a hydrogen atom or a monovalent organic group (the aforementioned monovalent organic group being bonded to the nitrogen atom via a carbon atom other than the carbonyl carbon), or a divalent organic group with a nitrogen-containing structure in the group consisting of an amino group.

[0023] Invention Effects

[0024] According to the liquid crystal alignment agent of the present invention, a liquid crystal alignment agent with excellent cost performance can be obtained, which can produce a liquid crystal alignment film with excellent resistance to AC image retention and low pretilt angle characteristics. Furthermore, liquid crystal display elements having liquid crystal alignment films formed using this liquid crystal alignment agent exhibit excellent viewing angle characteristics and high display quality.

[0025] The mechanism by which the above-mentioned effects of the present invention are obtained may not be clear, but it is generally presumed as follows. That is, it can be considered that by using two polyamic acids as polymer components for liquid crystal alignment agents, and using diamines with specific alkylene chain lengths in the raw material components of the two polyamic acids, a polymer with high linearity is formed, thus exhibiting the effect of improved resistance to AC image retention.

[0026] Furthermore, it can be considered that by using two different polyamic acids, which are moderately miscible, both high tolerance to AC residual images and low pretilt angle characteristics can be achieved. Attached Figure Description

[0027] Figure 1 This is a schematic cross-sectional view illustrating an example of a transverse electric field liquid crystal display element of the present invention.

[0028] Figure 2 This is a schematic cross-sectional view showing another example of the transverse electric field liquid crystal display element of the present invention. Detailed Implementation

[0029] The following describes the components of the liquid crystal alignment agent disclosed herein, as well as any other components that may be added as needed.

[0030] <Polyamic Acid (A)>

[0031] The diamine component of the polyamic acid (A) contained in the liquid crystal alignment agent used in the manufacture of the present invention contains the following formula (d AL The diamine shown in formula (d) AL The diamine shown can be used alone or in combination with two or more.

[0032]

[0033] (Formula (d) AL In this context, A represents the group "*". 11 -(CH2) n -O-* 12 (*) 11 This refers to a bond bonded to an oxygen atom or a bond bonded to a carbon atom that makes up the benzene ring. 12 This indicates a bonded bond. (n is an integer from 1 to 5) is a divalent organic group. Any hydrogen atom of the aforementioned benzene ring bonded to the NH₂ group may optionally be replaced by a monovalent group.

[0034] By using the above formula (d) AL As described above, option A improves resistance to AC residual images, and when using two polyamic acids, they are moderately miscible, resulting in low pretilt angle characteristics.

[0035] From the perspective of achieving high liquid crystal alignment, * 11Preferably, it is a bond bonded to an oxygen atom.

[0036] From the perspective of obtaining low pretilt angle characteristics, the group "*" 11 -(CH2) n -O-* 12 In the above, n is preferably an integer from 1 to 4, more preferably an integer from 1 to 3, and even more preferably an integer from 1 to 2.

[0037] From the perspective of achieving high liquid crystal orientation, the above equation (d) AL The two amino groups in ) are preferably in the para position with A.

[0038] From the viewpoint of achieving the desired effects of the present invention, the above formula (d) AL In the ), A is preferably a divalent organic group with 10 or fewer carbon atoms.

[0039] The above formula (d) AL In the ), as monovalent groups, the following can be listed: halogen atom, alkyl with 1 to 10 carbon atoms, alkenyl with 2 to 10 carbon atoms, alkoxy with 1 to 10 carbon atoms, fluoroalkyl with 1 to 10 carbon atoms, fluoroalkenyl with 2 to 10 carbon atoms, fluoroalkoxy with 1 to 10 carbon atoms, carboxyl, hydroxyl, alkoxycarbonyl with 1 to 10 carbon atoms, cyano, nitro, etc.

[0040] As the above formula (d) AL From the viewpoint of obtaining the effects of the present invention, the diamine represented by the following formula (d) is preferred. AL -1)~(d AL The diamine shown in -9).

[0041]

[0042] From the perspective of obtaining low pretilt angle characteristics, the above equation (d) AL -1)~(d AL -2) and (d AL -4)~(d AL In (-5), n is more preferably 1 to 4, further preferably 1 to 3, and even more preferably 1 to 2.

[0043] From the perspective of obtaining low pretilt angle characteristics, the above equation (d) AL In (-3), m and n are more preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 to 2.

[0044] The above formula (d) AL In equation (-6), n is further preferably 1 to 3, and even more preferably 1 to 2. ALIn (-6), m1 and m2 are each preferably 1 to 3, and even more preferably 1 to 2. Furthermore, from the viewpoint of obtaining low pretilt angle characteristics, the total of m1, m2, and n is preferably 10 or less.

[0045] From the perspective of obtaining low pretilt angle characteristics, the above equation (d) AL -7) and (d AL In (-9), n is more preferably 1 to 3, and even more preferably 1 to 2.

[0046] The above formula (d) AL In (-8), n is more preferably 1 to 4, further preferably 1 to 3, and even more preferably 1 to 2. The above formula (d) AL In (-8), m1 and m2 are each more preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 to 2. Furthermore, from the viewpoint of obtaining low pretilt angle characteristics, the total of m1, m2, and n is preferably 10 or less.

[0047] From the perspective of achieving high liquid crystal orientation, the above equation (d) AL -1)~(d AL In (-9), the two amino groups are preferably in the para position relative to the divalent organic groups that link the two benzene rings.

[0048] The above formula (d) is a component of the above polyamic acid (A). AL The content of the diamine shown in the formula is not particularly limited, but preferably it is 10 mol% or more of the total diamine component used to manufacture polyamic acid (A), more preferably 20 mol% or more, and even more preferably 50 mol% or more. When other diamines described later are used in conjunction, the content of the diamine in the formula (d) is... AL The content of the diamine shown is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less.

[0049] The diamine component of polyamic acid (A) used in the manufacture of the liquid crystal alignment agent of the present invention, in addition to using the above-described formula (d... AL In addition to the diamines shown above, various diamines (hereinafter also referred to as other diamines) may be used depending on the desired properties of the liquid crystal alignment agent. The following diamines may be used as other diamines. One diamine may be used alone, or two or more may be used in combination.

[0050] The above formula (d) nDiamines represented by the following formula (O); diamines with photo-oriented groups such as 4,4'-diaminoazobenzene or diaminodiphenylacetylene; diamines with amide or urea bonds such as the following formulas (h-1) to (h-5); 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 1,2-bis(4-aminophenyl)ethane, 1,2-bis(3-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1 3-bis(3-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,4-bis(3-aminophenyl)butane, 1,5-bis(4-aminophenyl)butane, 1,5-bis(4-aminophenyl)pentane, 1,5-bis(3-aminophenyl)pentane, 1,6-bis(4-aminophenyl)hexane, 1,6-bis(3-aminophenyl)hexane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, and the following formula (d o Diamines as shown in formulas (3b-1) to (3b-4); 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol; 4,4'-diamino-3,3'-dihydroxybiphenyl, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid and diamines with carboxyl groups as shown in formulas (3b-1) to (3b-4); 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indane-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indane-6-amine; 2-(2,4-diamino)methacrylate Diamines having photopolymerizable groups at the ends, such as phenoxyethyl ester and 2,4-diamino-N,N-diallylaniline; diamines having a steroidal skeleton, such as cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanosteryl 3,5-diaminobenzoate, and 3,6-bis(4-aminobenzoyloxy)cholestan; diamines shown in formulas (V-1) to (V-6) below; diamines having the group "-N(D)-" (D represents a protecting group that is removed by heating and replaced by a hydrogen atom, preferably tert-butoxycarbonyl) in formulas (5-1) to (5-9) below (wherein, formula (d nExcept for the diamines shown in the diagram; diamines with siloxane bonds such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; m-phenylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and diamines formed by bonding two amino groups to groups shown in any of the formulas (Y-1) to (Y-167) as described in International Publication No. 2018 / 117239.

[0051]

[0052] (p is an integer of 0 or 1. Ar represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring. Wherein, when p is 1, at least one of Ar represents a biphenyl structure or a naphthalene ring; in the above case, if one of the two Ar represents a biphenyl structure, the other represents a biphenyl structure or a naphthalene ring. The two Ar are optionally the same or different, and any hydrogen atom of the ring in the above Ar is optionally substituted with a monovalent group. Q2 represents -(CH2).) n -(n is an integer from 2 to 18), or -(CH2) n A group formed by replacing at least a portion of -CH2- with any one of -O-, -C(=O)-, and -O-C(=O)-. It should be noted that, as specific examples of monovalent groups, those in the above formula (d) AL The structures exemplified are those with monovalent groups in ().

[0053] Examples of formula (O) are described later.

[0054]

[0055] (In the case of two or more m, the two or more m may optionally be the same or different. One or more hydrogen atoms on the benzene ring may optionally be substituted by a monovalent group.)

[0056] Examples of equation (d0) are described later.

[0057]

[0058] (In equation (3b-1), A) 1 The expression represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)-, or -N(CH3)CO-, where m1 and m2 are independent integers from 0 to 4, and m1+m2 is an integer from 1 to 4.

[0059] In equation (3b-2), m3 and m4 are independent integers from 1 to 5.

[0060] In equation (3b-3), A 2 It represents a straight-chain or branched alkyl group with 1 to 5 carbon atoms, where m5 is an integer from 1 to 5.

[0061] In equation (3b-4), A 3 and A 4 Each of these can independently represent a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)-, or -N(CH3)CO-, where m6 is an integer from 1 to 4.

[0062]

[0063] (In formulas (V-1)~(V-6), X) v1 ~X v4 and X p 1 ~X p2 Each can be represented independently as -(CH2) a - (a is an integer from 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2O-, -CH2OCO-, -COO- or -OCO-, X v5 This represents -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-. X a Indicates a single bond, -O-, -NH-, or -O- (CH2). m -O- (m represents an integer from 1 to 6), R v1 ~R v4 and R 1 a ~R 1b Each of the two k groups independently represents an alkyl group with 1 to 20 carbon atoms, an alkoxy group with 1 to 20 carbon atoms, or an alkoxyalkyl group with 2 to 20 carbon atoms. The two k groups may optionally be the same or different.

[0064]

[0065] (In formulas (5-1) to (5-9), Boc represents tert-butoxycarbonyl.)

[0066] As the above formula (d) o Specific examples of monovalent groups in ) can be listed in the above formula (d ALThe structure is illustrated by an example of a monovalent group in ).

[0067] As the above formula (d) o From the viewpoint of improving liquid crystal alignment, the diamine shown in the following formula (d) is preferred. o -1)~(d o The diamines, 3,3'-diaminodiphenyl ethers, 3,4'-diaminodiphenyl ethers, and 4,4'-diaminodiphenyl ethers shown in (-6)

[0068]

[0069] In the diamine represented by formula (O) above, any hydrogen atom of the benzene ring, biphenyl structure, or naphthalene ring may optionally be substituted with a monovalent group. Specific examples of the aforementioned monovalent group can be listed in the above formula (d) AL Examples of structures are shown in the monovalent groups of ).

[0070] From the viewpoint of improving liquid crystal orientation, the diamines represented by the above formula (O) are preferred as diamines represented by the following formulas (o-1) to (o-8).

[0071]

[0072] The tetracarboxylic acid derivative component of the polyamic acid (A) used in the manufacture of the liquid crystal alignment agent of the present invention comprises 100 mol% of aromatic tetracarboxylic acid dianhydride of all tetracarboxylic acid derivative components.

[0073] Aromatic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to an aromatic ring.

[0074] The above-mentioned aromatic tetracarboxylic acid dianhydride is preferably of the following formula (t R The tetracarboxylic acid dianhydride shown is .

[0075]

[0076] In the formula X R For those selected from the following formula (X) R -1)~(X R The structure of -2).

[0077]

[0078] Formula (X) R -1)~(X R In (-2), j and k are integers of 0 or 1, and A1 and A2 independently represent single bonds, -O-, -CO-, -COO-, phenylene, sulfonyl, or amide groups, respectively. Multiple A2 groups may be identical or different. * indicates a bonded bond.

[0079] As the above formula (X) R -1)~(X R A preferred example of -2) can be listed as the following formula (X) R -3)~(X R -18). *Same meaning as above.

[0080]

[0081] From the perspective of improving liquid crystal alignment, the above-mentioned X R Preferably, the above (X) R -3)~(X R -10), more preferably (X) R -3), (X) R -6)~(X R -8) and (X R -10).

[0082] <Polyamic Acid (B)>

[0083] The diamine component of the polyamic acid (B) contained in the liquid crystal alignment agent used in the manufacture of the present invention contains the above formula (d AL The diamine shown in the figure and the above formula (d) n The diamine shown in the above formula (d) AL The diamine shown in the figure and the above formula (d) n The diamines shown can be used alone or in combination of two or more.

[0084] The above formula (d) is used to manufacture polyamic acid (B). AL The preferred embodiment of the diamine shown is the same as the above formula (d) used to manufacture polyamic acid (A). AL The preferred embodiment of the diamine shown is the same.

[0085] The above formula (d) is a component of the above polyamic acid (B). AL The content of the diamine shown is not particularly limited, but is preferably 5 to 80 mol% of all the diamine components used to synthesize polyamic acid (B), more preferably 10 to 70 mol%, and even more preferably 40 to 60 mol%.

[0086] As the above formula (d) nThe nitrogen-containing heterocycles in the ring include, for example: pyrrole ring, imidazole ring, pyrazole ring, triazole ring, pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, indole ring, benzimidazole ring, purine ring, quinoline ring, isoquinoline ring, naphthidine ring, quinoxaline ring, phthalazine ring, triazine ring, carbazole ring, acridine ring, piperidine ring, piperazine ring, pyrrolidine ring, hexamethyleneimine ring, etc. Among these, pyridine ring, pyrimidine ring, pyrazine ring, piperidine ring, piperazine ring, quinoline ring, carbazole ring, or acridine ring are preferred.

[0087] As the above formula (d) n The monovalent organic group R in ) can be, for example, alkyl groups such as methyl, ethyl, and propyl; alkenyl groups such as vinyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl and methylphenyl; alkoxy groups (e.g., methoxy and ethoxy). R is preferably a hydrogen atom or a methyl group.

[0088] As the above formula (d) n Specific examples of diamines shown in the figure include, for example: 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, or the following formula (d n -1)~(d n The diamine shown in -3).

[0089]

[0090] Formula (d) n In (-1), m1 and m1' are independent integers from 1 to 2. n1 is an integer from 1 to 3. R1 is related to the above "* 21 -NR-* 22 The R in the amino group shown has the same meaning.

[0091] In the presence of multiple R1 and m1', the multiple R1 and m1' may be the same or different.

[0092] Formula (d) n In equation (-2), X2 represents a monovalent nitrogen-containing heterocyclic group. Specific examples of nitrogen-containing heterocycles in this monovalent nitrogen-containing heterocyclic group can be listed in the above formula (d). n The structure is illustrated in the nitrogen-containing heterocycles in ).

[0093] n1 is an integer from 1 to 2, and n2 is an integer satisfying n1 + n2 = 2. L1 and L2 independently represent a single bond, -CO-, an alkylene group with 1 to 6 carbon atoms, or a divalent organic group formed by inserting -O- or -CO- between or at the end of the carbon-carbon bond of the alkylene group, and bonded to the nitrogen atom through a carbon atom. R represents a hydrogen atom or a methyl group.

[0094] In the presence of multiple X2, L2, and R, the multiple X2, L2, and R may be identical or different.

[0095] Formula (d) n In (-3), X3 represents a divalent group having a nitrogen-containing heterocycle. Specific examples of this nitrogen-containing heterocycle can be listed in the above formula (d). n The structure is illustrated in the nitrogen-containing heterocycles in ).

[0096] Ar3 represents a divalent aromatic cyclic group or a divalent saturated nitrogen-containing heterocyclic group. Specific examples of aromatic rings in divalent aromatic cyclic groups include: benzene rings, naphthalene rings, anthracene rings, pyridine rings, pyrimidine rings, pyrazine rings, pyridazine rings, triazine rings, pyrrole rings, imidazole rings, pyrazole rings, quinoline rings, isoquinoline rings, carbazole rings, benzimidazole rings, indole rings, quinoxaline rings, and acridine rings. Specific examples of saturated nitrogen-containing heterocyclic groups in divalent saturated nitrogen-containing heterocyclic groups include: piperidine rings and piperazine rings. Any hydrogen atom in the aromatic cyclic group and the saturated nitrogen-containing heterocyclic group may be optionally substituted with a monovalent group. Monovalent groups include those in the above formula (d...). AL The structures illustrated by the monovalent groups in ) are examples of such structures.

[0097] L3 represents a single bond, -(CH2). n -(n is an integer from 1 to 6), -NR'-, -(CH2) n -NR'- (n is an integer from 1 to 6), -O-, -NR'-CO-, -CO-NR'-, -O-CO- or -CO-O-, where R' represents a hydrogen atom, methyl or tert-butoxycarbonyl.

[0098] m3 and m3' are independent integers from 0 to 2, and either m3 or m3' is an integer greater than or equal to 1.

[0099] In the presence of multiple Ar3 and L3, the multiple Ar3 and L3 may be identical or different.

[0100] In addition, formula (d) n The NH2 groups in -3) are all bonded to carbon atoms that make up the aromatic ring.

[0101] As the above formula (d) n -1)~(d nPreferred specific examples of the diamines shown in (-3) include: the diamines shown in formulas (Dp-1) to (Dp-6) below, and the diamines shown in formulas (z-1) to (z-14) below.

[0102]

[0103] (Boc represents tert-butoxycarbonyl.)

[0104] The above formula (d) is a component of the above polyamic acid (B). n The content of the diamine shown is not particularly limited, but is preferably 20 to 95 mol% of all the diamine components used to manufacture polyamic acid (B), more preferably 30 to 90 mol%, and even more preferably 40 to 60 mol%.

[0105] Regarding the diamine component of polyamic acid (B) contained in the liquid crystal alignment agent used to manufacture the present invention, in addition to the diamine described above, various diamines (hereinafter also referred to as other diamines (b)) may be used depending on the desired characteristics of the liquid crystal alignment agent.

[0106] Other diamines (b) include, for example, compounds exemplified in the diamines used to manufacture the polyamic acid (A) described above. Each of these other diamines (b) may be used alone or in combination of two or more.

[0107] The tetracarboxylic acid derivative component of the polyamic acid (B) contained in the liquid crystal alignment agent of the present invention comprises at least 5 mol% of all tetracarboxylic acid derivative components, selected from at least one tetracarboxylic acid dianhydride selected from the group consisting of acyclic aliphatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides.

[0108] From the viewpoint of achieving the effects of the present invention, the combined amount of the above-mentioned acyclic aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride is more preferably 10 mol% or more of all tetracarboxylic acid derivative components used in the manufacture of polyamic acid (B), and more preferably 20 mol% or more.

[0109] Here, the acyclic aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. It is not necessary to consist solely of a chain hydrocarbon structure; a portion of it may also have an alicyclic or aromatic ring structure. The alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to an alicyclic structure. None of these four carboxyl groups are bonded to an aromatic ring. Furthermore, it is not necessary to consist solely of an alicyclic structure; a portion of it may also have a chain hydrocarbon structure or an aromatic ring structure. The aforementioned acyclic aliphatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides can be used alone or in combination of two or more.

[0110] By using noncyclic aliphatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides, polyamic acid (B) with a different composition from polyamic acid (A) can be obtained. Furthermore, it can be considered that by employing two different polyamic acids in the liquid crystal alignment agent of the present invention, with the two polyamic acids being moderately miscible, both high resistance to AC image retention and low pretilt angle characteristics can be achieved.

[0111] Regarding the acyclic aliphatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides in component (B) above, from the viewpoint of improving liquid crystal orientation, tetracarboxylic dianhydrides having at least one partial structure selected from the group consisting of cyclobutane ring structure, cyclopentane ring structure and cyclohexane ring structure are preferred.

[0112] The noncyclic aliphatic tetracarboxylic dianhydride or alicyclic tetracarboxylic dianhydride is preferably the tetracarboxylic dianhydride shown in the following formula (t).

[0113]

[0114] In the formula, X1 is a structure selected from the following formulas (X1-1)~(X1-23).

[0115]

[0116]

[0117] In equations (X1-1)~(X1-4), R1~R 21 Each of these groups independently represents a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, an alkynyl group with 2 to 6 carbon atoms, a monovalent organic group containing a fluorine atom with 1 to 6 carbon atoms, or a phenyl group. * indicates a bond. From the viewpoint of improving liquid crystal orientation, R1 to R 21 Preferably, hydrogen atoms, halogen atoms, methyl or ethyl groups are used, and more preferably hydrogen atoms or methyl groups are used.

[0118] As specific examples of formula (X1-1), formulas (1-1) to (1-6) can be listed below. From the viewpoint of improving liquid crystal alignment, formula (1-1) is particularly preferred. *Same meaning as above.

[0119]

[0120] From the viewpoint of improving liquid crystal orientation, X1 in the above formula (t) is preferably (X1-1) to (X1-10), (X1-18) to (X1-23), more preferably (X1-1) to (X1-2), (X1-5), (X1-7) to (X1-10), (X1-21) or (X1-23), and even more preferably (1-1), (1-2), (X1-2) or (X1-7) to (X1-10).

[0121] Regarding the tetracarboxylic acid derivative component of the polyamic acid (B) used in the manufacture of the liquid crystal alignment agent of the present invention, in addition to using the aforementioned acyclic aliphatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides or other tetracarboxylic dianhydrides (also collectively referred to as other tetracarboxylic dianhydrides (b)) may be used, depending on the desired characteristics of the liquid crystal alignment agent. Preferred specific examples of aromatic tetracarboxylic dianhydrides used in the manufacture of polyamic acid (B) are the same as those for the manufacture of polyamic acid (A) described above.

[0122] When the tetracarboxylic acid (B) derivative component of the polyamic acid (B) used in the manufacture of the liquid crystal alignment agent of the present invention includes other tetracarboxylic dianhydrides (b), the content of the other tetracarboxylic dianhydrides (b) is preferably 5 to 95 mol% of all tetracarboxylic acid derivative components used in the manufacture of polyamic acid (B), more preferably 10 to 90 mol%, and even more preferably 20 to 80 mol%. Furthermore, in this case, the combined amount of the above-mentioned acyclic aliphatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides is preferably 5 to 95 mol% of all tetracarboxylic acid derivative components, more preferably 10 to 90 mol%, and even more preferably 20 to 80 mol%.

[0123] Regarding the content ratio of the above-mentioned components (A) and (B), from the viewpoint of obtaining the effect of the present invention, the content ratio of components (A) and (B) based on the mass ratio of [(A) component] / [(B) component] can be 10 / 90 to 90 / 10, 20 / 80 to 90 / 10, or 20 / 80 to 80 / 20.

[0124] <Manufacturing of Polyamic Acid (A) and Polyamic Acid (B)>

[0125] Polyamic acid can be manufactured, for example, by the following method. Specifically, it can be synthesized by subjecting a tetracarboxylic acid derivative component containing the above-mentioned tetracarboxylic acid dianhydride and a diamine component containing the above-mentioned diamine to a polycondensation reaction in the presence of an organic solvent at -20 to 150°C, preferably at 0 to 50°C, for 30 minutes to 24 hours, preferably for 1 to 12 hours.

[0126] Specific examples of organic solvents used in the above reactions include: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolinone, etc. Furthermore, where the polymer has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or solvents shown in formulas [D-1] to [D-3] below can be used. Two or more of these can be mixed.

[0127]

[0128] (In formula [D-1], D) 1 In formula [D-2], D represents an alkyl group with 1 to 3 carbon atoms. 2 In formula [D-3], D represents an alkyl group having 1 to 3 carbon atoms. 3 (Refers to alkyl groups with 1 to 4 carbon atoms).

[0129] The reaction can be carried out at any concentration, preferably 1-50% by mass, more preferably 5-30% by mass. Alternatively, the reaction can be carried out at a high concentration initially, followed by the addition of solvent. In the reaction, the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic acid component is preferably 0.8-1.2. Similar to conventional polycondensation reactions, the closer this molar ratio is to 1.0, the larger the molecular weight of the resulting polyamic acid.

[0130] The polyamic acid obtained in the above reaction can be precipitated and recovered by injecting it into a poor solvent while the reaction solution is thoroughly stirred. Alternatively, after several precipitation processes, washing with a poor solvent, and drying at room temperature or by heating, purified polyamic acid powder can be obtained. Poor solvents are not particularly limited, but examples include: water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

[0131] [End-capping agent]

[0132] In the synthesis of the polyamic acids (A) and (B) of this invention, a suitable capping agent can also be used with a tetracarboxylic acid derivative component containing tetracarboxylic acid dianhydride and a diamine component to synthesize a capped polymer.

[0133] Examples of capping agents include: acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, benzotriacic anhydride, 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynyl phthalic anhydride, etc.; dicarbonate diesters such as ditert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinyl chloride; aniline, 2 Monoamine compounds such as -aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, etc.; monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, 2-acryloyloxyethyl isocyanate, and 2-methacryloyloxyethyl isocyanate, etc., which contain unsaturated bonds; and isothiocyanate compounds such as ethyl isothiocyanate and allyl isothiocyanate, etc.

[0134] The proportion of the capping agent used is preferably 20 moles or less, more preferably 10 moles or less, relative to the total of 100 moles of the diamine component and the organic diol component used as needed.

[0135] When recovering polyamic acid from a reaction solution, the reaction solution can be precipitated by adding it to a solvent. Examples of solvents for precipitation include methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polyamic acid precipitated in the solvent can be filtered and recovered, and then dried at room temperature or under normal or reduced pressure. Furthermore, repeating the process 2 to 10 times to redissolve the recovered polymer in an organic solvent and perform reprecipitation can reduce impurities in the polymer. Examples of solvents used in this process include alcohols, ketones, and hydrocarbons. Using three or more solvents selected from these sources further increases purification efficiency and is therefore preferred.

[0136] The molecular weights of the polyamic acid (A) and polyamic acid (B) used in this invention, taking into account the strength of the liquid crystal alignment film obtained therefrom, the workability during film formation, and the coating properties, are preferably set to 5,000 to 1,000,000, more preferably 10,000 to 150,000, based on the weight-average molecular weight determined by GPC (Gel Permeation Chromatography).

[0137] The liquid crystal alignment agent of the present invention may also contain polymers other than polyamic acid (A) and polyamic acid (B). Specific examples of other polymers include polymers selected from the group consisting of: polyamic acid esters, polyimides, polysiloxanes, polyesters, polyamides, polyureas, polyurethanes, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-maleic anhydride) copolymers, poly(isobutylene-maleic anhydride) copolymers, poly(vinyl ether-maleic anhydride) copolymers, poly(styrene-phenylmaleimide) derivatives, and poly(meth)acrylates. Specific examples of poly(styrene-maleic anhydride) copolymers include: SMA1000, 2000, 3000 (manufactured by CrayValley); GSM301 (manufactured by Gifu Shellac), etc. Specific examples of poly(isobutylene-maleic anhydride) copolymers include ISOBAM-600 (manufactured by Kuraray), and specific examples of poly(vinyl ether-maleic anhydride) copolymers include GANTREZ AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by ISP Japan).

[0138] Other polymers may be used alone or in combination of two or more. The proportion of other polymers relative to 100 parts by weight of the total polymers contained in the liquid crystal alignment agent is preferably 90 parts by weight or less, more preferably 10 to 90 parts by weight, and even more preferably 20 to 80 parts by weight.

[0139] The liquid crystal alignment agent of the present invention is preferably a liquid composition formed by dissolving or dispersing the above-mentioned polyamic acid (A) and polyamic acid (B) in an organic solvent. Specifically, the organic solvent contained in the above-mentioned liquid crystal alignment agent is not particularly limited as long as it uniformly dissolves the polyamic acid; examples include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactic acid, N,N-dimethylpropionamide, tetramethylurea, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methyl... Oxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone (also collectively referred to as "good solvents"), etc. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, or γ-butyrolactone are preferred. The content of the good solvent is preferably 20 to 99% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass.

[0140] In addition to the solvents mentioned above, the organic solvents contained in the liquid crystal alignment agent preferably include a mixed solvent that also contains a solvent (also called a poor solvent) that improves the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent. Specific examples of the poor solvents used are described below, but are not limited thereto. The content of the poor solvent is preferably 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. The type and content of the poor solvent are appropriately selected according to the coating apparatus, coating conditions, coating environment, etc.

[0141] Examples of undesirable solvents include: diisopropyl ether, diisobutyl ether, diisobutylmethanol (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 monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy)-2-propanol, etc. 1-Propanol (2-(2-ethoxyethoxy)-1-propanol), propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, 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, cyclohexyl acetate, 4-methyl-2-pentyl 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.

[0142] Among them, diisobutyl methanol, 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 or diisobutyl ketone are preferred.

[0143] Preferred combinations of solvents, representing good and poor solvents, include: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-dimethyllactic acid and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate and diisobutyl ketone; N,N-dimethyllactic acid and ethyl 3-ethoxypropionate and diisobutyl ketone; N-methyl-2-pyrrolidone ... Propylene glycol monomethyl ether; N-ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether; N-ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether; N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether acetate; N-ethyl-2-pyrrolidone with dipropylene glycol dimethyl ether; N,N-dimethyllacticamide with ethylene glycol monobutyl ether; N,N-dimethyllacticamide with propylene glycol diacetate; N-ethyl-2-pyrrolidone with diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone with diethylene glycol monoethyl ether and butyl cellosolve acetate; N-methyl-2-pyrrolidone with diethylene glycol monomethyl ether and... Butyl cellolytic acetate; N,N-dimethyl lactamide with diethylene glycol diethyl ether; N-methyl-2-pyrrolidone with γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone with N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol monobutyl ether; N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with diisobutyl ketone; N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol monobutyl ether; N-Methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol dimethyl ether; γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether and diisobutylmethanol; N-methyl-2-pyrrolidone with γ-butyrolactone and dipropylene glycol dimethyl ether.N-Methyl-2-pyrrolidone with propylene glycol monobutyl ether and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone with diethylene glycol diethyl ether and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether and propylene glycol diacetate; N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether and diisobutyl ketone; N-ethyl-2-pyrrolidone with γ-butyrolactone and diisobutyl ketone; N-ethyl-2-pyrrolidone with N,N-dimethyllactic acid and diisobutyl ketone. Acetyl ketones; N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate; γ-butyrolactone with ethylene glycol monobutyl ether acetate and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone with ethylene glycol monobutyl ether acetate and propylene glycol dimethyl ether; N-methyl-2-pyrrolidone with 4-methyl-2-pentyl acetate and ethylene glycol monobutyl ether; N-ethyl-2-pyrrolidone with cyclohexyl acetate and diacetone alcohol; cyclohexanone with propylene glycol monomethyl ether; cyclopentanone with propylene glycol monomethyl ether; N-methyl-2-pyrrolidone with cyclohexanone and propylene glycol monomethyl ether, etc.

[0144] (Liquid crystal alignment agent)

[0145] The liquid crystal alignment agent of the present invention may also contain additional components (hereinafter also referred to as additive components) other than components (A), (B), and organic solvents described above. Examples of such additive components include: at least one crosslinking compound selected from the group consisting of crosslinking compounds having at least one substituent selected from epoxy groups, isocyanate groups, oxetyl groups, cyclic carbonate groups, terminal isocyanate groups, hydroxyl groups, and alkoxy groups, and crosslinking compounds having polymerizable unsaturated groups; functional silane compounds; metal chelating compounds; curing accelerators; surfactants; antioxidants; sensitizers; preservatives; and compounds for adjusting the dielectric constant and resistance of the resin film.

[0146] As preferred specific examples of the above-mentioned crosslinking compounds, compounds represented by any of the following formulas (CL-1) to (CL-11) can be listed.

[0147]

[0148] Compounds used to adjust the dielectric constant and resistance of the aforementioned resin film include monoamines such as 3-aminomethylpyridine, which have an aromatic heterocycle containing a nitrogen atom. When using a monoamine with an aromatic heterocycle containing a nitrogen atom, its content is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, more preferably 0.1 to 20 parts by mass.

[0149] Preferred specific examples of functional silane compounds 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, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane. The compounds include 3-hydroxypropyltrimethoxysilane, 3-hydroxypropylmethyldiethoxysilane, 3-hydroxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, tris(3-trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatepropyltriethoxysilane. When using functional silane compounds, their content is preferably 0.1 to 30 parts by weight, more preferably 0.1 to 20 parts by weight, relative to 100 parts by weight of the polymer component contained in the liquid crystal alignment agent.

[0150] The concentration of solid components in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent in the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) should be appropriately selected considering factors such as viscosity and volatility, and is preferably in the range of 1 to 10% by mass.

[0151] The particularly preferred range of solid component concentration varies depending on the method used to coat the liquid crystal alignment agent onto the substrate. For example, when using spin coating, the solid component concentration is particularly preferably in the range of 1.5 to 4.5% by mass. When using printing, the solid component concentration is particularly preferably in the range of 3 to 9% by mass, thereby setting the solution viscosity to the range of 12 to 50 mPa·s. When using inkjet printing, the solid component concentration is particularly preferably in the range of 1 to 5% by mass, thereby setting the solution viscosity to the range of 3 to 15 mPa·s. The temperature for preparing the polymer composition is preferably 10 to 50°C, more preferably 20 to 30°C.

[0152] The liquid crystal alignment agent described above can be effectively applied to various technical applications, such as liquid crystal alignment films (liquid crystal alignment films for phase difference films; liquid crystal alignment films for scanning antennas and liquid crystal array antennas; or liquid crystal alignment films for transmission and scattering type liquid crystal dimming elements), protective films (e.g., protective films for color filters), spacer films, interlayer insulating films, anti-reflective films, wiring coating films, anti-charge films, motor insulating films (gate insulating films for flexible displays), etc.

[0153] [Liquid crystal alignment film and liquid crystal display element]

[0154] A liquid crystal alignment film can be manufactured using the aforementioned liquid crystal alignment agent. Furthermore, the liquid crystal display element of the present invention includes a liquid crystal alignment film formed using the aforementioned liquid crystal alignment agent. The operating mode of the liquid crystal display element of the present invention is not particularly limited, and it can be applied to various operating modes such as TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, vertical alignment type (including VA-MVA (Multi-domain Vertical Alignment) type, VA-PVA (Patterned Vertical Alignment) type, planar conversion type (IPS type, FFS type), and optically compensated birefringence type (OCB).

[0155] The liquid crystal display element of the present invention includes, for example, the following processes (1) to (3).

[0156] The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following steps (1) to (4), a method including steps (1) to (2) and (4), a method including steps (1) to (3), (4-2) and (4-4), or a method including steps (1) to (3), (4-3) and (4-4).

[0157] <Process (1): The process of coating the liquid crystal alignment agent onto the substrate>

[0158] Step (1) is the process of coating the liquid crystal alignment agent of the present invention onto the substrate. A specific example of step (1) is described below.

[0159] For example, the liquid crystal alignment agent of the present invention is coated onto one side of a substrate having a patterned transparent conductive film using a suitable coating method such as a roller coater, spin coater, printing, or inkjet printer. As for the substrate, there are no particular limitations as long as it is a highly transparent substrate; it can be used in conjunction with glass substrates, silicon nitride substrates, or plastic substrates such as acrylic substrates or polycarbonate substrates. Furthermore, in reflective liquid crystal display elements, if only a single-sided substrate is used, an opaque material such as a silicon wafer can be used, and the electrodes can be made of light-reflecting materials such as aluminum. Moreover, in the manufacture of IPS or FFS type liquid crystal display elements, a substrate having electrodes composed of a patterned comb-shaped transparent conductive film or metal film and an opposing substrate without electrodes are used.

[0160] Methods for coating a liquid crystal alignment agent onto a substrate to form a film include screen printing, offset printing, flexographic printing, inkjet printing, and spraying. Among these, inkjet printing is preferred.

[0161] <Step (2): The process of firing the coated liquid crystal alignment agent to obtain a film>

[0162] Step (2) is a process of firing the liquid crystal alignment agent coated on the substrate to obtain a film. A specific example of step (2) is described below.

[0163] After the liquid crystal alignment agent is coated onto the substrate in step (1), the solvent can be evaporated by a heating unit such as a heating plate, a thermal cycling oven, or an IR (infrared) oven; or thermal imidization of polyamic acid can be performed. The drying and firing steps after coating the liquid crystal alignment agent of the present invention can be performed at any temperature and time, and can be repeated multiple times. For example, the firing temperature for the liquid crystal alignment agent can be 40 to 180°C. From the viewpoint of shortening the process, it can be performed at 40 to 150°C. The firing time is not particularly limited, and examples include 1 to 10 minutes or 1 to 5 minutes. In the case of thermal imidization of polyamic acid, a firing step can be added after the above steps, for example, in a temperature range of 150 to 300°C or 150 to 250°C. The firing time is not particularly limited, and examples include 5 to 40 minutes or 5 to 30 minutes.

[0164] If the film thickness of the fired film is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, it is preferred to be 5 to 300 nm, and more preferably 10 to 200 nm.

[0165] <Step (3): The step of oriented treatment of the film obtained in step (2)>

[0166] Step (3) is a step of aligning the film obtained in step (2) as appropriate. That is, in horizontally aligned liquid crystal display elements such as IPS or FFS, the coating is subjected to an alignment capability imparting treatment. On the other hand, in vertically aligned liquid crystal display elements such as VA or PSA (Polymer-Sustained Alignment) mode, the formed coating can be kept in this state and used as a liquid crystal alignment film, or the coating can be subjected to an alignment capability imparting treatment. As an alignment treatment method for liquid crystal alignment films, brushing treatment and photo-alignment treatment can be listed. As a photo-alignment treatment method, the following method can be listed: irradiating the surface of the above-mentioned film with radiation biased in a certain direction, and, depending on the situation, preferably performing a heat treatment at a temperature of 150 to 250°C to impart liquid crystal alignment (also known as liquid crystal alignment capability). As radiation, ultraviolet light or visible light with a wavelength of 100 to 800 nm can be used. Among them, ultraviolet light with a wavelength of 100 to 400 nm is preferred, and ultraviolet light with a wavelength of 200 to 400 nm is more preferred.

[0167] The preferred radiation dose is 1–10,000 mJ / cm². 2 The preferred concentration is 100–5000 mJ / cm³. 2 Furthermore, to improve liquid crystal alignment when irradiated with radiation, the substrate having the above-mentioned film can be irradiated while being heated at 50–250°C. The liquid crystal alignment film produced in this way allows the liquid crystal molecules to be stably aligned in a specific direction.

[0168] Furthermore, in the above methods, water or solvents can be used to contact the liquid crystal alignment film irradiated with polarized radiation; or the liquid crystal alignment film irradiated with radiation can be heated.

[0169] The solvent used for the above-mentioned contact treatment is not particularly limited as long as it dissolves the decomposition products generated by the film-like material through radiation irradiation. Specific examples include: water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, etc. The solvent can be one type or a combination of two or more.

[0170] The temperature for heat treatment of the radiation-irradiated coating is more preferably 50–300°C, and even more preferably 120–250°C. The heat treatment time is preferably set to 1–30 minutes.

[0171] <Process (4): Process of manufacturing LCD cell>

[0172] In step (4), two substrates with liquid crystal alignment films formed as described above are prepared, and liquid crystal is disposed between the two substrates that are arranged opposite each other. Specifically, the following two methods can be listed.

[0173] In the first method, two substrates are first arranged opposite each other with a gap (cell gap) between them, with each liquid crystal alignment film facing each other. Next, the peripheries of the two substrates are bonded together using a sealant, and a liquid crystal composition is injected into the cell gap defined by the substrate surface and the sealant. After contact with the film surface, the injection hole is sealed.

[0174] In addition, a second method is known as the ODF (One Drop Fill) method. For example, a UV-curable sealant is applied to a predetermined area on one of two substrates on which a liquid crystal alignment film has been formed. Then, a liquid crystal composition is dropped onto several predetermined points on the surface of the alignment film. Next, the other substrate is bonded with the alignment film facing it, and the liquid crystal composition is spread across the entire surface of the substrate, contacting the film surface. Then, the entire surface of the substrate is irradiated with UV light to cure the sealant. Regardless of the method used, it is ideal to further heat the liquid crystal composition to a temperature at which it becomes an isotropic phase, and then slowly cool it to room temperature, thereby removing the flow alignment during liquid crystal filling.

[0175] It should be noted that when the coating is brushed, the two substrates are arranged at a predetermined angle to each other with the brushing direction of each coating, for example, in an orthogonal or antiparallel manner.

[0176] As a sealant, epoxy resin containing a curing agent and alumina balls as spacers can be used, for example.

[0177] There are no particular limitations on the liquid crystal composition described above; it is a composition containing at least one liquid crystal compound (liquid crystal molecule), and various liquid crystal compositions with positive or negative dielectric anisotropy can be used. It should be noted that, hereinafter, liquid crystal compositions with positive dielectric anisotropy are referred to as positive liquid crystals, and liquid crystal compositions with negative dielectric anisotropy are referred to as negative liquid crystals.

[0178] The aforementioned liquid crystal compositions may include liquid crystal compounds having the following groups: fluorine atoms, hydroxyl groups, amino groups, fluorine-containing groups (e.g., trifluoromethyl), cyano groups, alkyl groups, alkoxy groups, alkenyl groups, isothiocyanate groups, heterocyclic groups, cycloalkanes, cycloolefins, steroidal skeletons, benzene rings, or naphthalene rings. They may also include compounds having two or more rigid sites (mesocrystalline skeletons) within the molecule that exhibit liquid crystal properties (e.g., bimesocrystalline compounds formed by two rigid biphenyl or terphenyl structures linked by an alkyl group). Furthermore, examples of liquid crystal compositions include nematic liquid crystal compositions, smectic liquid crystal compositions, or cholesteric liquid crystal compositions, with nematic liquid crystal compositions being preferred.

[0179] Furthermore, from the viewpoint of improving liquid crystal orientation, the above-mentioned liquid crystal composition may further contain additives. Examples of such additives include: photopolymerizable monomers such as compounds having polymerizable groups; optically active compounds (e.g., S-811 manufactured by MERCK Co., Ltd.); antioxidants; ultraviolet absorbers; pigments; defoamers; polymerization initiators; or polymerization inhibitors.

[0180] Examples of positive liquid crystal displays include: ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081 manufactured by MERCK.

[0181] Examples of negative liquid crystals include MLC-6608, MLC-6609, MLC-6610, and MLC-7026-100 manufactured by MERCK.

[0182] Furthermore, as a liquid crystal composition used in the PSA-type liquid crystal display element described later, MLC-3023 manufactured by MERCK Corporation is an example of a liquid crystal containing a polymeric compound.

[0183] From the viewpoint of obtaining the desired effect of the present invention, the liquid crystal alignment agent of the present invention preferably uses positive liquid crystal.

[0184] The liquid crystal alignment agent of the present invention is also preferably used in a liquid crystal display element (PSA type liquid crystal display element) formed by having a liquid crystal layer between a pair of substrates having electrodes and manufactured by the following steps: disposing a liquid crystal composition containing a polymerizable compound that is polymerized by at least one of active energy rays and heat between a pair of substrates, applying a voltage between the electrodes, and polymerizing the polymerizable compound by at least one of irradiation by active energy rays and heat.

[0185] Furthermore, the liquid crystal alignment agent of the present invention is also preferably used in a liquid crystal display element (SC-PVA type liquid crystal display element) formed by having a liquid crystal layer between a pair of substrates having electrodes and manufactured by the following process: a liquid crystal alignment film containing polymeric groups polymerized by at least one of active energy rays and heat is disposed between the pair of substrates, and a voltage is applied between the electrodes.

[0186] <Process (4-2): PSA type liquid crystal display element>

[0187] In step (4-2), a liquid crystal composition containing a polymerizable compound is injected or dropped, except in this respect, the same as step (4) described above. Examples of polymerizable compounds include polymeric compounds having one or more polymerizable unsaturated groups such as acrylate groups or methacrylate groups within their molecules.

[0188] <Process (4-3): Case of SC-PVA type liquid crystal display element>

[0189] As step (4-3), a method for manufacturing liquid crystal display elements can also be adopted, which involves the same process as step (4) described above, followed by an ultraviolet irradiation process described later. According to this method, similar to the case of manufacturing the PSA-type liquid crystal display element described above, a liquid crystal display element with excellent response speed under a small amount of light irradiation can be obtained. The compound having polymerizable groups can be a compound having one or more of the aforementioned polymeric unsaturated groups within its molecule, and its content relative to 100 parts by mass of the total polymer component is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass. Furthermore, the aforementioned polymerizable groups can be present in the polymer used as a liquid crystal alignment agent; for example, a polymer obtained by reacting a diamine component containing a diamine terminally having the aforementioned photopolymerizable groups can be cited.

[0190] <Process (4-4): Process of irradiating with ultraviolet light>

[0191] In step (4-4), the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates obtained in step (4-2) or step (4-3). The applied voltage can be, for example, DC or AC of 5-50V. Furthermore, the irradiation light can be, for example, ultraviolet light or visible light with wavelengths of 150-800nm, preferably ultraviolet light with wavelengths of 300-400nm. The light source can be, 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. The irradiation intensity is preferably 1000-200000 J / m². 2 More preferably, it is 1000 to 100000 J / m 2 .

[0192] Furthermore, a liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell as needed. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include: a polarizing plate made by sandwiching a polarizing film called an "H film" that extends and oriented polyvinyl alcohol while absorbing iodine using a cellulose acetate protective film; or a polarizing plate made of the H film itself.

[0193] Furthermore, a liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell as needed. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include: a polarizing plate made by sandwiching a polarizing film called an "H film" that extends and oriented polyvinyl alcohol while absorbing iodine using a cellulose acetate protective film; or a polarizing plate made of the H film itself.

[0194] The IPS substrate, which is a comb electrode substrate used in IPS mode, has: a substrate; a plurality of linear electrodes formed on the substrate and configured in a comb shape; and a liquid crystal alignment film formed on the substrate to cover the linear electrodes.

[0195] It should be noted that the FFS substrate, which is used as a comb electrode substrate in FFS mode, has: a substrate; a surface electrode formed on the substrate; an insulating film formed on the surface electrode; a plurality of linear electrodes formed on the insulating film and arranged in a comb shape; and a liquid crystal alignment film formed on the insulating film to cover the linear electrodes.

[0196] Figure 1 This is a schematic cross-sectional view showing an example of a lateral electric field liquid crystal display element of the present invention, which is an example of an IPS mode liquid crystal display element.

[0197] exist Figure 1 In the lateral electric field liquid crystal display element 1 illustrated in the example, liquid crystal 3 is held between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2c and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 has: a substrate 2a; a plurality of linear electrodes 2b formed on the substrate 2a and arranged in a comb-like configuration; and a liquid crystal alignment film 2c formed on the substrate 2a to cover the linear electrodes 2b. The opposing substrate 4 has: a substrate 4b; and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2c is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4c is also, similarly, the liquid crystal alignment film of the present invention.

[0198] In this transverse electric field liquid crystal display element 1, when a voltage is applied to the linear electrode 2b, an electric field is generated between the linear electrodes 2b as shown by the electric field line L.

[0199] Figure 2This is a schematic cross-sectional view showing another example of the transverse electric field liquid crystal display element of the present invention, which is an example of an FFS mode liquid crystal display element.

[0200] exist Figure 2 In the lateral electric field liquid crystal display element 1 illustrated in the example, liquid crystal 3 is sandwiched between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2h and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 has: a substrate 2d; a surface electrode 2e formed on the substrate 2d; an insulating film 2f formed on the surface electrode 2e; a plurality of linear electrodes 2g formed on the insulating film 2f and arranged in a comb-like configuration; and a liquid crystal alignment film 2h formed on the insulating film 2f to cover the linear electrodes 2g. The opposing substrate 4 has: a substrate 4b; and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2h is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4a is also, like the liquid crystal alignment film of the present invention.

[0201] In this transverse electric field liquid crystal display element 1, when a voltage is applied to the surface electrode 2e and the linear electrode 2g, an electric field is generated between the surface electrode 2e and the linear electrode 2g as shown by the electric field line L.

[0202] In addition to the liquid crystal alignment film used for the purposes described above, the liquid crystal alignment film of the present invention can be applied to various other applications, such as liquid crystal alignment films for phase retardation films, liquid crystal alignment films for scanning antennas, liquid crystal array antennas, or liquid crystal alignment films for transmission-scattering type liquid crystal dimming elements. Furthermore, it can also be used for applications other than liquid crystal alignment films, such as protective films (e.g., protective films for color filters), spacer films, interlayer insulating films, anti-reflective films, wiring coating films, anti-static films, and motor insulating films (gate insulating films for flexible displays).

[0203] The liquid crystal display element of the present invention can be effectively applied to various devices, such as clocks, portable game consoles, word processors, laptops, in-vehicle navigation systems, portable camcorders, PDAs (Personal Digital Assistants), digital cameras, portable telephones, smartphones, various monitors, LCD TVs, information displays, and other display devices.

[0204] Example

[0205] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. It should be noted that the abbreviations for compounds and solvents are as follows.

[0206] NMP: N-methyl-2-pyrrolidone.

[0207] BCS: Butyl cellosolve.

[0208] CA-1 to CA-4: These are compounds with the following structural formulas, respectively.

[0209] DA-1 to DA-6: These are compounds with the following structural formulas, respectively.

[0210] AD-1:3-Epoxypropoxypropyltriethoxysilane.

[0211] AD-2: A compound with the following structural formula.

[0212]

[0213]

[0214] <Polymer Synthesis>

[0215] (Synthesis example 1)

[0216] 2.93 g (12.0 mmol) of DA-2 and 1.19 g (3.0 mmol) of DA-3 were measured into a 100 mL flask equipped with a stirrer and a nitrogen inlet tube. 30.2 g of NMP was added, and the mixture was stirred while supplying nitrogen gas to dissolve the diamine solution. While stirring the solution under water cooling, 3.11 g (14.3 mmol) of CA-1 was added, followed by 22.8 g of NMP. The mixture was stirred at 50 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution A-1 containing polyamic acid.

[0217] (Synthesis example 2)

[0218] 3.44 g (12.0 mmol) of DA-1 and 1.19 g (3.0 mmol) of DA-3 were measured into a 100 mL flask equipped with a stirrer and a nitrogen inlet tube. 33.9 g of NMP was added, and the mixture was stirred while supplying nitrogen gas to dissolve the diamine solution. While stirring the solution under water cooling, 3.11 g (14.3 mmol) of CA-1 was added, followed by 22.8 g of NMP. The mixture was stirred at 50 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution A-2 containing polyamic acid.

[0219] (Synthesis example 3)

[0220] 4.30 g (15.0 mmol) of DA-1 was measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 31.5 g of NMP was added, and the solution was dissolved by stirring while introducing nitrogen gas. While stirring the diamine solution under water cooling, 3.11 g (14.3 mmol) of CA-1 was added, followed by 22.8 g of NMP. The mixture was stirred at 50 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution A-3 containing polyamic acid.

[0221] (Synthesis Example 4)

[0222] 2.15 g (7.5 mmol) of DA-1, 1.10 g (4.5 mmol) of DA-2, and 1.19 g (3.0 mmol) of DA-3 were measured into a 100 mL flask equipped with a stirrer and a nitrogen inlet tube. 32.5 g of NMP was added, and the solution was stirred while introducing nitrogen gas to dissolve the DA-1. While stirring the diamine solution under water cooling, 3.11 g (14.3 mmol) of CA-1 was added, followed by 22.8 g of NMP. The mixture was stirred at 50 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution A-4 containing polyamic acid.

[0223] (Synthesis Example 5)

[0224] 3.66 g (15.0 mmol) of DA-2 was measured into a 100 mL flask equipped with a stirrer and a nitrogen inlet tube. 26.9 g of NMP was added, and the mixture was stirred while supplying nitrogen gas to dissolve the DA-2. While stirring the diamine solution under water cooling, 3.11 g (14.3 mmol) of CA-1 was added, followed by 22.8 g of NMP. The mixture was stirred at 50 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution A-5 containing polyamic acid.

[0225] (Synthesis Example 6)

[0226] 2.81 g (11.5 mmol) of DA-2 and 2.29 g (11.5 mmol) of DA-4 were measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 28.9 g of NMP was added, and the solution was stirred while introducing nitrogen gas to dissolve the DA-4. While stirring the diamine solution under water cooling, 0.95 g (4.8 mmol) of CA-2 was added, followed by 5.4 g of NMP. The mixture was stirred at 23 °C for 30 minutes under a nitrogen atmosphere. Then, while stirring the solution under water cooling, 4.32 g (17.3 mmol) of CA-3 was added, followed by 24.5 g of NMP. The mixture was stirred at 50 °C for 12 hours under a nitrogen atmosphere to obtain polymer solution B-1 containing polyamic acid.

[0227] (Synthesis Example 7)

[0228] 2.44 g (10.0 mmol) of DA-2 and 1.99 g (10.0 mmol) of DA-4 were measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 25.1 g of NMP was added, and the solution was stirred while introducing nitrogen gas to dissolve the DA-2. While stirring the diamine solution under water cooling, 3.75 g (15.0 mmol) of CA-3 was added, followed by 21.3 g of NMP. The mixture was stirred at 50 °C for 2 hours under a nitrogen atmosphere. Then, while stirring the solution under water cooling, 1.25 g (4.3 mmol) of CA-4 was added, followed by 7.1 g of NMP. The mixture was stirred at 70 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution B-2 containing polyamic acid.

[0229] (Synthesis Example 8)

[0230] 2.86 g (10.0 mmol) of DA-1 and 1.99 g (10.0 mmol) of DA-4 were measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 27.5 g of NMP was added, and the solution was stirred while introducing nitrogen gas to dissolve the DA-1. While stirring the diamine solution under water cooling, 3.75 g (15.0 mmol) of CA-3 was added, followed by 21.3 g of NMP. The mixture was stirred at 50 °C for 2 hours under a nitrogen atmosphere. Then, while stirring the solution under water cooling, 1.25 g (4.3 mmol) of CA-4 was added, followed by 7.1 g of NMP. The mixture was stirred at 70 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution B-3 containing polyamic acid.

[0231] (Synthesis Example 9)

[0232] 3.67 g (18.4 mmol) of DA-4 and 0.91 g (4.6 mmol) of DA-5 were measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 25.9 g of NMP was added, and the solution was stirred while introducing nitrogen gas to dissolve the DA-4. While stirring the diamine solution under water cooling, 0.91 g (4.6 mmol) of CA-2 was added, followed by 5.4 g of NMP. The mixture was stirred at 23 °C for 30 minutes under a nitrogen atmosphere. Then, while stirring the solution under water cooling, 4.32 g (17.3 mmol) of CA-3 was added, followed by 24.5 g of NMP. The mixture was stirred at 50 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution C-1 containing polyamic acid.

[0233] (Synthesis Example 10)

[0234] 2.29 g (11.5 mmol) of DA-4 and 2.28 g (11.5 mmol) of DA-5 were measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 25.9 g of NMP was added, and the solution was stirred while introducing nitrogen gas to dissolve the DA-4. While stirring the diamine solution under water cooling, 0.95 g (4.8 mmol) of CA-2 was added, followed by 5.4 g of NMP. The mixture was stirred at 23 °C for 30 minutes under a nitrogen atmosphere. Then, while stirring the solution under water cooling, 4.32 g (17.3 mmol) of CA-3 was added, followed by 24.5 g of NMP. The mixture was stirred at 50 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution C-2 containing polyamic acid.

[0235] (Synthesis Example 11)

[0236] 2.29 g (11.5 mmol) of DA-4 and 1.75 g (11.5 mmol) of DA-6 were measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 22.9 g of NMP was added, and the solution was stirred while introducing nitrogen gas to dissolve the DA-6. While stirring the diamine solution under water cooling, 0.95 g (4.8 mmol) of CA-2 was added, followed by 5.4 g of NMP. The mixture was stirred at 23 °C for 30 minutes under a nitrogen atmosphere. Then, while stirring the solution under water cooling, 4.32 g (17.3 mmol) of CA-3 was added, followed by 24.5 g of NMP. The mixture was stirred at 50 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution C-3 containing polyamic acid.

[0237] (Synthesis Example 12)

[0238] 2.29 g (11.5 mmol) of DA-4 and 1.75 g (11.5 mmol) of DA-6 were measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 22.9 g of NMP was added, and the solution was stirred while introducing nitrogen gas to dissolve the DA-6. While stirring the diamine solution under water cooling, 2.07 g (10.6 mmol) of CA-2 was added, followed by 11.8 g of NMP. The mixture was stirred at 23 °C for 30 minutes under a nitrogen atmosphere. Then, while stirring the solution under water cooling, 2.87 g (11.5 mmol) of CA-3 was added, followed by 16.2 g of NMP. The mixture was stirred at 50 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution C-4 containing polyamic acid.

[0239] (Synthesis Example 13)

[0240] 3.19 g (16.0 mmol) of DA-4 and 0.79 g (4.0 mmol) of DA-5 were measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 22.6 g of NMP was added, and the solution was stirred while introducing nitrogen gas to dissolve the DA-4. While stirring the diamine solution under water cooling, 2.50 g (10.0 mmol) of CA-3 was added, followed by 14.2 g of NMP. The mixture was stirred at 50 °C for 2 hours under a nitrogen atmosphere. Then, while stirring the solution under water cooling, 2.71 g (9.2 mmol) of CA-4 was added, followed by 15.4 g of NMP. The mixture was stirred at 70 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution C-5 containing polyamic acid.

[0241] (Synthesis Example 14)

[0242] 1.99 g (10.0 mmol) of DA-4 and 1.98 g (10.0 mmol) of DA-5 were measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 22.5 g of NMP was added, and the solution was dissolved by stirring while introducing nitrogen gas. While stirring the diamine solution under water cooling, 3.75 g (15.0 mmol) of CA-3 was added, followed by 21.3 g of NMP. The mixture was stirred at 50 °C for 2 hours under a nitrogen atmosphere. Then, while stirring the solution under water cooling, 1.24 g (4.2 mmol) of CA-4 was added, followed by 7.0 g of NMP. The mixture was stirred at 70 °C for 12 hours under a nitrogen atmosphere to obtain a polymer solution C-6 containing polyamic acid.

[0243] The types and amounts of diamine and tetracarboxylic acid components used in synthetic examples 1–14 are summarized in Table 1.

[0244] [Table 1]

[0245]

[0246] <Preparation of Liquid Crystal Alignment Agent>

[0247] (Example 1)

[0248] Using polymer solutions A-1 and B-1, polymer solution A-1 (7.5 g) and polymer solution B-1 (14.0 g) were mixed in a mass ratio of 30:70. While stirring, NMP (12.1 g), BCS (12.5 g), an NMP solution containing 1% by mass of AD-1 (3.0 g), and an NMP solution containing 10% by mass of AD-2 (0.9 g) were added to the mixture, and the mixture was further stirred at room temperature for 2 hours, thereby obtaining the liquid crystal alignment agent AL-1 of the present invention.

[0249] (Examples 2-5 and Comparative Examples 1-10)

[0250] By performing the same operations as in Example 1 according to the composition shown in Table 2 below, the liquid crystal alignment agents AL-2 to AL-5 of Examples 2 to 5 of the present invention and the liquid crystal alignment agents AL-C1 to AL-C10 of Comparative Examples 1 to 10 were obtained.

[0251] [Table 2]

[0252]

[0253] <Making of LCD Cells>

[0254] The FFS-driven liquid crystal cell shown below was fabricated using the liquid crystal alignment agent obtained therein.

[0255] [The structure of an FFS-driven liquid crystal cell]

[0256] The liquid crystal cell used in FFS mode combines a first glass substrate and a second glass substrate. The first glass substrate has an FOP (Fingeron Plate) electrode layer formed on its surface, consisting of a common electrode in a planar shape, an insulating layer, and pixel electrodes in a comb-like shape. The second glass substrate has columnar spacers with a height of 4 μm on its surface and an ITO film for preventing charge accumulation on its back side. The pixel electrodes have a comb-like shape formed by multiple electrode elements with a width of 3 μm and a 160° bend at the inner angle, spaced 6 μm apart in parallel. A pixel has a first region and a second region, with the bend connecting the multiple electrode elements as its boundary. It should be noted that the liquid crystal alignment film formed on the first glass substrate is aligned such that the direction dividing the inner angle of the pixel bend is orthogonal to the alignment direction of the liquid crystal. The liquid crystal alignment film formed on the second glass substrate is aligned such that the alignment direction of the liquid crystal on the first glass substrate is consistent with the alignment direction of the liquid crystal on the second glass substrate during the fabrication of the liquid crystal cell.

[0257] [The manufacturing sequence of the LCD cell]

[0258] Using spin coating, a liquid crystal alignment agent filtered through a 1.0 μm pore size filter was applied to the surface of each of the aforementioned glass substrates, and dried on a heating plate at 80°C for 2 minutes. Afterwards, it was fired in a hot air circulating oven at 230°C for 30 minutes to obtain a substrate with a liquid crystal alignment film of 100 nm thickness. The surface of the substrate with the liquid crystal alignment film was brushed with rayon cloth (Yoshikawa Chemical Co., Ltd., YA-20R) (roller diameter: 120 mm, roller speed: 1000 rpm, moving speed: 20 mm / sec, pressing length: 0.4 mm), then cleaned by ultrasonic irradiation in pure water for 1 minute. After removing water droplets using a blower, it was dried at 80°C for 15 minutes to obtain the substrate with the liquid crystal alignment film.

[0259] Next, spherical spacers with a particle size of 4 μm were dispersed on the liquid crystal alignment film surface of one of the aforementioned substrates with liquid crystal alignment films. A liquid crystal injection port was left open, and a sealant (Mitsui Chemicals XN-1500T) was printed around it. The substrates were then bonded to the other substrate with the liquid crystal alignment film surfaces facing each other and their respective brushing directions being antiparallel. Afterward, a heat treatment at 150°C for 60 minutes was performed to cure the sealant, creating an empty cell. Liquid crystal MLC-3019 (MERCK Corporation, positive liquid crystal) was injected into this empty cell using a depressurized injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. The resulting liquid crystal cell was then heated at 120°C for 1 hour, left to stand overnight, and various evaluations were performed.

[0260] <Characteristic Evaluation of LCD Cells>

[0261] The characteristics of the liquid crystal cell manufactured in this manner were evaluated as follows.

[0262] [Viewpoint Characteristics]

[0263] The pretilt angle of the liquid crystal cell was measured using the "OPTIPRO-micro" instrument manufactured by SHIINTECH. Generally speaking, the smaller the pretilt angle, the better the viewing angle characteristics. Specifically, a pretilt angle below 2.0 degrees is rated as "○", and a pretilt angle greater than 2.0 degrees is rated as "×".

[0264] [Afterimage characteristics based on long-term communication]

[0265] The FFS-driven liquid crystal cell fabricated above was subjected to an AC voltage of 60Hz ±7V for 120 hours under a backlight illumination of 15000 nits. Afterwards, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited, and the cell was left at room temperature for one day. For the liquid crystal cell subjected to the above treatment, the offset between the alignment direction of the liquid crystal in the first region and the alignment direction of the liquid crystal in the second region of the pixel under the no-voltage applied state was calculated in the form of an angle.

[0266] Specifically, a liquid crystal cell is placed between two polarizing plates orthogonally positioned on their polarization axes. The backlight is turned on, and the arrangement angle of the liquid crystal cell is adjusted to minimize the transmitted light intensity in the first region of the pixel. Then, the required rotation angle Δ to minimize the transmitted light intensity in the second region of the pixel is determined. It can be said that the smaller the value of this rotation angle Δ, the better the image retention characteristics based on long-term AC drive. Specifically, a rotation angle Δ less than 0.05 degrees is rated as "○", and a value greater than 0.05 degrees is rated as "×".

[0267] <Evaluation Results>

[0268] The evaluation results of the liquid crystal cells using the liquid crystal alignment agents of the above embodiments and comparative examples are shown in Table 3.

[0269] [Table 3]

[0270]

[0271] It can be said that the liquid crystal display element using the liquid crystal alignment agent of the present invention has a small pretilt angle and good image retention characteristics.

[0272] Explanation of reference numerals in the attached figures

[0273] 1: Lateral electric field liquid crystal display element; 2: Comb electrode substrate; 2a: Substrate; 2b: Linear electrode; 2c: Liquid crystal alignment film; 2d: Substrate; 2e: Surface electrode; 2f: Insulating film; 2g: Linear electrode; 2h: Liquid crystal alignment film; 3: Liquid crystal; 4: Opposite substrate; 4a: Liquid crystal alignment film; 4b: Substrate; L: Electric field line.

Claims

1. A liquid crystal aligning agent, characterized by, (A) component and a (B) component described below, (A) Component: Polyamic acid (A) which is a reaction product of a tetracarboxylic acid derivative component containing 100 mole % of an aromatic tetracarboxylic dianhydride of the total tetracarboxylic acid derivative component and a diamine component containing a diamine represented by the following formula (d AL ) (B) Component: Polyamic acid (B) which is a reaction product of a tetracarboxylic acid derivative component containing at least one tetracarboxylic dianhydride selected from the group consisting of acyclic aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride in an amount of 5% by mole or more of the total tetracarboxylic acid derivative component, and a diamine component containing a diamine represented by the following formula (d AL ) and a diamine represented by the following formula (d n ), In the formula (d AL ), A represents a divalent organic group having a group "*" 11 - (CH2) n - O - 12 " wherein 11 represents a bond to an oxygen atom or a bond to a carbon atom constituting a benzene ring, * 12 represents a bond; n is an integer of 1 to 5; and any hydrogen atom of the benzene ring bonded to the NH2 group is optionally substituted with a monovalent group, Formula (d) n In the diagram, Y represents a heterocycle and group selected from nitrogen atoms. 21 -NR-* 22 The group consisting of amino groups, which are divalent organic groups containing nitrogen atoms, is shown in the figure. 21 and* 22 The term "bond" indicates a bond bonded to a carbon atom that constitutes an aromatic ring, wherein the carbon atom does not form a ring with the nitrogen atom bonded to R; R represents a hydrogen atom or a monovalent organic group, wherein the monovalent organic group is bonded to the nitrogen atom through a carbon atom other than the carbonyl carbon.

2. The liquid crystal aligning agent according to claim 1, wherein The content of the diamine represented by the formula (d AL in the constitutional components of the polyamic acid (A) is 10 mol% or more of the total diamine components used for the production of the polyamic acid (A).

3. The liquid crystal aligning agent according to claim 1 or 2, wherein The content of the diamine represented by the formula (d AL in the constitutional components of the polyamic acid (B) is 5 to 80 mol% of the total diamine components used for the production of the polyamic acid (B).

4. The liquid crystal aligning agent according to claim 1 or 2, wherein The content of the diamine represented by the formula (d n in the constitutional components of the polyamic acid (B) is 20 to 95 mole% of the total diamine components used for the production of the polyamic acid (B).

5. The liquid crystal aligning agent according to claim 1 or 2, wherein The diamine represented by the formula (d AL ) is a diamine represented by the formula (d AL ) shown below. AL (d-1) to (d-9) shown below. 。 6. The liquid crystal aligning agent according to claim 1 or 2, wherein the diamine represented by formula (d n ) is at least one diamine selected from the group consisting of 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, and diamines represented by formulae (d n -1) to (d n -3) below, Formula (d n -1) wherein m1and m1' are each independently an integer of 1 to 2; n1is an integer of 1 to 3; R1is the same as the meaning of R in the amino group represented by the formula 21 -NR- 22 " and R1is the same as the meaning of R in the amino group represented by the formula in the case where a plurality of R1and m1' are present, the plurality of R1and m1' are optionally the same or different, Formula (d n In the formula (2), X2represents a monovalent nitrogen atom-containing heterocyclic group; n1is an integer of 1 to 2, and n2is an integer satisfying n1+ n2= 2; L1and L2independently represent a single bond, -CO-, an alkylene group having 1 to 6 carbon atoms, or a divalent organic group in which -O- or -CO- is inserted between carbon-carbon bonds or at a terminal of the alkylene group having 1 to 6 carbon atoms, and which is bonded to a nitrogen atom via a carbon atom; and R represents a hydrogen atom or a methyl group. in the case where a plurality of X2, L2and R are present, the plurality of X2, L2and R are optionally the same or different, Formula (d n In -3), X3represents a divalent group having a heterocycle containing a nitrogen atom; Ar3represents a divalent aromatic cyclic group or a divalent saturated heterocyclic group containing a nitrogen atom; any hydrogen atom of the aromatic cyclic group and the saturated heterocyclic group containing a nitrogen atom is optionally substituted with a monovalent group, L3represents a single bond, - (CH2) n -, - NR' -, - (CH2) n - NR' -, - O -, - NR' - CO -, - CO - NR' -, - O - CO - or - CO - O -, R' represents a hydrogen atom, a methyl group or a tert-butoxycarbonyl group, said - (CH2) n -, n is an integer of 1 to 6, said - (CH2) n - NR' -, n is an integer of 1 to 6, m3and m3' are each independently an integer of 0 to 2, and any of m3and m3' is an integer of 1 or more, in the case where a plurality of Ar3and L3are present, the plurality of Ar3and L3are optionally the same or different.

7. The liquid crystal aligning agent according to claim 1 or 2, wherein the non-cyclic aliphatic tetracarboxylic dianhydride and the alicyclic tetracarboxylic dianhydride in the (B) component are tetracarboxylic dianhydrides having at least one partial structure selected from the group consisting of a cyclobutane ring structure, a cyclopentane ring structure and a cyclohexane ring structure.

8. The liquid crystal aligning agent according to claim 1 or 2, wherein the content ratio of the (A) component and the (B) component is 10 / 90 to 90 / 10 in terms of the mass ratio of the (A) component / (B) component.

9. A liquid crystal aligning film formed using the liquid crystal aligning agent according to any one of claims 1 to 8.

10. A liquid crystal display element provided with the liquid crystal aligning film according to claim 9.

11. A method for producing a liquid crystal display element, comprising the following steps 1 to 3, Step 1: a step of applying the liquid crystal aligning agent according to any one of claims 1 to 8 to a substrate; Step 2: a step of performing firing on the applied liquid crystal aligning agent to obtain a film; and Step 3: a step of performing an alignment treatment on the film obtained in Step 2.

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