Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

Abstract

This invention provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element that can suppress image retention caused by long-term AC driving and reduce the deviation of the torsion angle of liquid crystal within the liquid crystal alignment film surface. One liquid crystal alignment agent is characterized by comprising at least one polymer (A) selected from the group consisting of a polyimide precursor having a repeating unit (a1) shown in formula (1) and an imide derivative of the polyimide precursor. (R1 to R4 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group; at least one of R1 to R4 represents a group other than a hydrogen atom as defined above. R and Z each independently represent a hydrogen atom or a monovalent organic group. Y1 represents a divalent organic group as shown in the following formula (H).) (R a This indicates a monovalent organic group consisting of a hydroxyl group, a halogen atom, or 1 to 3 carbon atoms. a is 1 to 4. In the presence of multiple R... a In this case, they may be the same or different. * indicates a bond.

Description

Technical Field

[0001] This invention relates to liquid crystal alignment agents, liquid crystal alignment films, and liquid crystal display elements. Background Technology

[0002] Liquid crystal displays (LCDs) are widely used as display units in personal computers, smartphones, mobile phones, televisions, and other devices. An LCD typically includes: a liquid crystal layer sandwiched between a display element substrate and a color filter substrate; pixel electrodes and a common electrode that apply an electric field to the liquid crystal layer; an alignment film that controls the orientation of the liquid crystal molecules in the liquid crystal layer; and a thin-film transistor (TFT) that converts the electrical signals supplied to the pixel electrodes; etc. Known driving methods for liquid crystal molecules include: vertical electric field methods such as TN (Twisted Nematic) and VA (Vertical Alignment); and lateral electric field methods such as IPS (In-Plane Switching) and FFS (Fringe Field Switching).

[0003] The most common industrially produced liquid crystal alignment films are manufactured through a so-called rubbing process, which involves rubbing the surface of a film made of polyamic acid and / or imidized polyimide, formed on an electrode substrate, in a unidirectional direction using a cloth such as cotton, nylon, or polyester. Rubbing is a simple and highly productive industrially useful method. However, with the increasing performance, precision, and size of liquid crystal display elements, various problems arising from rubbing, such as surface damage, dust generation, the effects of mechanical force and static electricity, and inhomogeneities within the alignment surface, have become apparent. As an alternative to rubbing, photoalignment methods, which impart alignment capabilities to liquid crystals by irradiating them with polarized radiation, are known. Regarding photoalignment methods, methods utilizing photoisomerization reactions, photocrosslinking reactions, and photodecomposition reactions have been proposed (see, for example, Non-Patent Literature 1, Patent Literature 1, and Patent Literature 2).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 9-297313

[0007] Patent Document 2: Japanese Patent Application Publication No. 2004-206091

[0008] Non-patent literature

[0009] Non-patent literature 1: "Functional Materials", November 1997, Vol. 17, No. 11, pp. 13-22 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] In the liquid crystal alignment film used in liquid crystal display elements with the aforementioned IPS and FFS driving methods, a high alignment constraint force is required to suppress image retention (hereinafter also referred to as AC image retention) generated by long-term AC driving. Furthermore, when the alignment process is performed using a photo-alignment method, the amount of light irradiation becomes a factor affecting energy costs and production speed; therefore, it is preferable to perform the alignment process with a small amount of light irradiation.

[0012] However, the inventors conducted research and found that, for example, liquid crystal alignment films that can achieve liquid crystal alignment with a small amount of light during the alignment process using photo-alignment methods have the following technical problems: the range of light irradiation required to obtain a liquid crystal alignment film that can suppress AC image retention is narrow, and the range of light irradiation required to obtain a liquid crystal alignment film with small deviations (non-uniformity) in the torsion angle of the liquid crystal within the liquid crystal alignment film surface is also narrow. Therefore, the following potential problems exist: the risk of AC image retention caused by liquid crystal driving is increased, making it difficult to obtain liquid crystal display elements with excellent contrast and high display quality; in the pursuit of larger screen sizes for liquid crystal display elements, some of the obtained liquid crystal alignment films may have incomplete liquid crystal alignment, resulting in in-plane brightness deviations during long-term image display and reduced display quality.

[0013] Therefore, the object of the present invention is to provide a liquid crystal alignment agent capable of efficiently obtaining a liquid crystal alignment film with high characteristics, the liquid crystal alignment film described above, and a liquid crystal display element using the liquid crystal alignment film described above. The high characteristics include, for example, the ability to suppress image retention caused by long-term AC drive even when the range of light irradiation during the alignment process performed by photo-alignment is small, and the ability to reduce the deviation (non-uniformity) of the twist angle of the liquid crystal within the liquid crystal alignment film surface.

[0014] Solution for solving the problem

[0015] The inventors conducted in-depth research and discovered that the above-mentioned technical problems could be solved by using a liquid crystal alignment agent containing specific components, thus completing the present invention.

[0016] Specifically, the present invention has the following solution.

[0017] A liquid crystal alignment agent, characterized in that it comprises at least one polymer (A) selected from the group consisting of a polyimide precursor having a repeating unit (a1) as shown in the following formula (1) and a polyimide as an imide derivative of the polyimide precursor.

[0018]

[0019] (In formula (1), R1 to R4 each independently represent 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 with 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. At least one of R1 to R4 represents a group other than a hydrogen atom as defined above. R and Z each independently represent a hydrogen atom or a monovalent organic group. Y1 represents a divalent organic group as shown in formula (H) below.)

[0020]

[0021] (In formula (H), R) a This indicates a hydroxyl group, a halogen atom, or a monovalent organic group with 1 to 3 carbon atoms. 'a' is an integer from 1 to 4. Furthermore, in the presence of multiple R... a In this case, they may be the same or different. * indicates a bond.

[0022] It should be noted that in this specification, the "integer" in cases where "a is an integer from 1 to 4" is obviously an "integer" is sometimes omitted. Furthermore, * in all cases represents a bond.

[0023] Invention Effects

[0024] According to the present invention, a liquid crystal alignment agent capable of efficiently obtaining a high-performance liquid crystal alignment film, the liquid crystal alignment film, and a liquid crystal display element using the liquid crystal alignment film are provided. The high performance characteristics include, for example, the ability to suppress AC image retention even when the range of light irradiation during the alignment process performed by photo-alignment is small, and the ability to reduce the deviation (non-uniformity) of the twist angle of the liquid crystal within the liquid crystal alignment film surface.

[0025] The mechanism by which the above-mentioned effects of the present invention are obtained may not be clear, but the following can be considered as one of the reasons. The polymer (A) contained in the liquid crystal alignment agent of the present invention comprises repeating units derived from substituted phenylenediamine. By including such repeating units, it is possible to adjust the imidization rate during thermal imidization, adjust the intermolecular interactions of the polymer, and make it easier to control the glass transition temperature of the polymer during the alignment process. Therefore, it can be considered that the mobility of the polymer during the alignment process is increased, thereby improving the anisotropy of the alignment film and obtaining the above-mentioned effects. Attached Figure Description

[0026] Figure 1 This is a schematic cross-sectional view of an example of a liquid crystal display element having a lateral electric field liquid crystal film obtained by the liquid crystal alignment agent of the present invention.

[0027] Figure 2This is a schematic cross-sectional view of another example of a liquid crystal display element having a lateral electric field liquid crystal film obtained by the liquid crystal alignment agent of the present invention. Detailed Implementation

[0028] <Polymer (A)>

[0029] The liquid crystal alignment agent of the present invention contains at least one polymer (A) selected from the group consisting of a polyimide precursor having a repeating unit (a1) as shown in formula (1) and a polyimide as an imide derivative of the polyimide precursor. It should be noted that polymer (A) may be composed of one or more polymers.

[0030]

[0031] In the above formula (1), R1 to R4 each independently represent 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 with 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, and at least one of R1 to R4 represents a group other than a hydrogen atom as defined above.

[0032] R and Z each independently represent a hydrogen atom or a monovalent organic group. Y1 represents a divalent organic group as shown in the following formula (H).

[0033]

[0034] In the above formula (H), R a This indicates a hydroxyl group, a halogen atom, or a monovalent organic group with 1 to 3 carbon atoms. a is 1 to 4. Furthermore, the presence of multiple R groups... a In this case, they may be the same or different.

[0035] R in the above formula (H) a The halogen atom in the formula (H) can be fluorine, chlorine, bromine, or iodine, with fluorine being preferred. From the viewpoint of obtaining the best effect of the present invention, a in the above formula (H) is preferably 1 to 3, and more preferably 1 to 2.

[0036] From the viewpoint of obtaining the good effects of the present invention, the divalent organic group represented by the above formula (H) is preferably the divalent organic group represented by the following formula (H').

[0037]

[0038] (R a And 'a' has the same meaning as in equation (H) above.

[0039] Specific examples of alkyl groups having 1 to 6 carbon atoms in R1 to R4 include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, and n-pentyl. Specific examples of alkenyl groups having 2 to 6 carbon atoms in R1 to R4 include vinyl, propenyl, and butenyl, which are optionally linear or branched. Specific examples of alkynyl groups having 2 to 6 carbon atoms in R1 to R4 include ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, and 3-butynyl. As for the halogen atom in R1 to R4, examples include R in the above formula (H). a Examples of halogen atoms are shown. Examples of monovalent organic groups containing fluorine atoms and having 1 to 6 carbon atoms among R1 to R4 include fluoromethyl, trifluoromethyl, pentafluoroethyl, and pentafluoropropyl. From the viewpoint of high photoreactivity, it is preferable that each of R1 to R4 is either a hydrogen atom or a methyl group; more preferably, at least one of R1 to R4 is a methyl group, and even more preferably, at least two of R1 to R4 are methyl groups. Even more preferably, it is preferable that R1 and R4 are methyl groups, and R2 and R3 are hydrogen atoms.

[0040] As a monovalent organic group in the above formula (H), examples include alkyl groups, at least a portion of the hydrogen atoms on the alkyl group being halogenated (as a specific example of a halogen atom, R in the above formula (H) can be listed). a Examples of halogen atoms are shown. Halogenated alkyl groups, alkoxy groups, and halogenated alkoxy groups formed by replacing at least a portion of the hydrogen atoms on the alkoxy group with halogen atoms are also mentioned. Examples of alkyl groups with 1 to 3 carbon atoms include structures with 1 to 3 carbon atoms within the structures shown as examples of alkyl groups from R1 to R4. Examples of halogenated alkyl groups include fluoromethyl, trifluoromethyl, pentafluoroethyl, and pentafluoropropyl. Among these, methyl or methoxy groups are preferred as monovalent organic groups with 1 to 3 carbon atoms.

[0041] From the viewpoint of obtaining the good effects of the present invention, the divalent organic group represented by the above formula (H) is preferably any one of the following formulas (h-1) to (h-16).

[0042]

[0043] As monovalent organic groups in R and Z in the above formula (1), the following can be listed: monovalent hydrocarbon groups with 1 to 20 carbon atoms, and groups consisting of -O-, -S-, -CO-, -COO-, -COS-, and -NR-. 3 -、-CO-NR 3 -, -Si(R) 3 )2-(where R 3It is a monovalent hydrocarbon group with 1 to 10 carbon atoms, and has multiple R atoms. 3 In the case of each R 3 The monovalent group A is formed by replacing the methylene group of the hydrocarbon group with a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), hydroxyl, alkoxy, nitro, amino, mercapto, nitroso, alkylsilyl, alkoxysilyl, silanol, sulfinyl, phosphin, carboxyl, cyano, sulfonic acid, acyl, etc., with at least one hydrogen atom bonded to a carbon atom of the monovalent hydrocarbon group or monovalent group A, or a monovalent group having a heterocyclic ring. As the monovalent organic group R and Z in the above formula (1), it is preferably an alkyl group with 1 to 10 carbon atoms, an alkenyl group with 2 to 10 carbon atoms, an alkynyl group with 2 to 10 carbon atoms, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group, more preferably an alkyl group with 1 to 3 carbon atoms, and even more preferably a methyl group.

[0044] From the viewpoint of obtaining the good effects of the present invention, R and Z are each preferably hydrogen atoms or alkyl groups having 1 to 3 carbon atoms, more preferably hydrogen atoms or methyl groups.

[0045] From the viewpoint of achieving the desired effects of the present invention, the polymer (A) described above can be at least one polymer selected from the group consisting of a polyimide precursor and a polyimide that is an imide derivative of the polyimide precursor, wherein the polyimide precursor has a repeating unit (a1) as shown in formula (1) above, and further has a repeating unit (a2) as shown in formula (2) below. It should be noted that the repeating unit (a2) is optionally composed of one or more types.

[0046]

[0047] In equation (2) above, R1 to R4, R, and Z have the same meaning as in equation (1) above. Y2 represents the divalent organic group shown in equation (O) below.

[0048] *-Ar-Q2-Ar-*(O)

[0049] In the above formula (O), Ar independently represents a benzene ring, a biphenyl structure, or a naphthalene ring. Any hydrogen atom on the Ar ring may optionally be replaced by a halogen atom or a monovalent organic group. Q2 represents –(CH2). n -(n is 2 to 18), or replace the above -(CH2) with any one of -O-, -C(=O)-, or -O-C(=O)-. n - A group that is part of a group.

[0050] In the above formula (O), examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms. Examples of monovalent organic groups include alkyl groups with 1 to 3 carbon atoms, alkenyl groups with 2 to 3 carbon atoms, alkynyl groups with 2 to 3 carbon atoms, and monovalent organic groups with 1 to 3 carbon atoms containing fluorine atoms. Specific examples of these monovalent organic groups include the groups exemplified in R1 to R4 above.

[0051] From the viewpoint of improving liquid crystal orientation, the divalent organic group represented by formula (O) above is preferably any one of the divalent organic groups represented by formulas (O-1) to (O-14) below. In formula (O-10), m is preferably 2. In formula (O-14), m is more preferably 0 or 2.

[0052]

[0053]

[0054] (In equation (o-14), the two m's are independent.)

[0055] From the viewpoint of obtaining the good effects of the present invention, the polymer (A) can be at least one polymer selected from the group consisting of a polyimide precursor and a polyimide as an imide derivative of the polyimide precursor, wherein the polyimide precursor has a repeating unit (a1) shown in formula (1), or the repeating unit (a1) and the repeating unit (a2) shown in formula (2), and further has at least one selected from the group consisting of a repeating unit (a2') shown in formula (2') and a repeating unit (a3) ​​shown in formula (3).

[0056]

[0057] In equations (2') and (3) above, X 2’ X3 represents a tetravalent organic group, Y 2’ Y2 represents the divalent organic group shown in the following formula (O2), and Y3 represents a divalent organic group with 6 to 30 carbon atoms having the group "-N(D)- (D represents a carbamate protecting group)" in the molecule. R and Z have the same meaning as in the case of formula (1) above.

[0058]

[0059] In the above formula (O2), m is an integer from 0 to 2, and Ar 2’ This represents an unsubstituted or substituted benzene ring. Where, when m is 0, Ar... 2’ Ar represents an unsubstituted benzene ring, where m is 1 to 2. 2’Each of these terms independently represents an unsubstituted benzene ring, or a benzene ring formed by replacing any hydrogen atom on the benzene ring with a halogen atom or a monovalent organic group (e.g., an alkyl group with 1 to 3 carbon atoms, an alkenyl group with 2 to 3 carbon atoms, an alkynyl group with 2 to 3 carbon atoms, a monovalent organic group with 1 to 3 carbon atoms containing a fluorine atom, etc.). Q 2’ Indicates a single bond or -O-. In the presence of multiple Ar... 2’ Q 2’ In this case, they may be the same or different.

[0060] From the viewpoint of minimizing AC remnant generation, the divalent organic group represented by the above formula (O2) is preferably any one of the following formulas (o2-1) to (o2-12).

[0061]

[0062] In formula (3) above, D in Y3 represents a urethane-based protecting group. Examples of urethane-based protecting groups include tert-butoxycarbonyl or 9-fluorenylmethoxycarbonyl. As a specific example of Y3 above, a divalent organic group represented by the following formula (Dx) can be listed.

[0063]

[0064] In the above formula (Dx), Q5 is a single bond, -(CH2). n -(n is 1 to 20), or -(CH2) n Any -CH2- is replaced by -O-, -Si(CH3)2-, -COO-, -OCO-, -NQ9-, -NQ9-CO-, -CO-NQ9-, -NQ9-CO-NQ 10 -, -NQ9-COO- or -O-COO- groups are substituted with Q9 and Q 10 Each can independently represent a hydrogen atom or a monovalent organic group.

[0065] Q6 and Q7 each independently represent -H, -NHD, -N(D)2, a group having -NHD, or a group having -N(D)2. Wherein, when m=0, Q6 has a urethane-based protecting group; where m=1, at least one of Q5, Q6, and Q7 has a urethane-based protecting group in its group. Furthermore, in Q6 and Q7, when representing a group having -NHD or a group having -N(D)2, the preferred number of carbon atoms in Q6 and Q7 is 1 to 30, more preferably 1 to 8.

[0066] As mentioned above, Q9 and Q 10Monovalent organic groups can be listed as alkyl groups with 1 to 3 carbon atoms, alkenyl groups with 2 to 3 carbon atoms, alkynyl groups with 2 to 3 carbon atoms, and monovalent organic groups with 1 to 3 carbon atoms containing fluorine atoms. As specific examples, groups with 1 to 3 carbon atoms in the groups shown in R1 to R4 above can be listed.

[0067] As a preferred specific example of Y3, from the viewpoint of minimal AC afterimage, any of the divalent organic groups shown in formulas (Y3-1) to (Y3-9) below can be listed. Boc represents tert-butoxycarbonyl.

[0068]

[0069] X in equations (2') and (3) above 2’ In addition to the tetravalent organic group shown in formula (g) below, X3 may also include any tetravalent organic group shown in formulas (X-1) to (X-25) below, tetravalent organic groups derived from aromatic tetracarboxylic acid dianhydrides, etc. From the viewpoint of obtaining the best effects of the present invention, X 2’ X3 is more preferably a tetravalent organic group as shown in the following formula (g).

[0070]

[0071] (R1~R4 have the same meaning as R1~R4 in the above formula (1).)

[0072]

[0073] The aforementioned aromatic tetracarboxylic acid dianhydrides are obtained by intramolecular dehydration of the carboxyl groups bonded to aromatic rings such as benzene and naphthalene rings. Specific examples include any tetravalent organic group represented by any one of the following formulas (Xa-1) to (Xa-2) and any tetravalent organic group represented by any one of the following formulas (Xr-1) to (Xr-7).

[0074]

[0075] (x and y are each independently a single bond, ether group, carbonyl group, ester group, alkane diel group with 1 to 10 carbon atoms, 1,4-phenylene group, sulfonyl group, or amide bond. j and k are 0 or 1.)

[0076]

[0077] The tetravalent organic group represented by formula (Xa-1) or (Xa-2) above may optionally be any one of the structures shown in formulas (Xa-3) to (Xa-19) below.

[0078]

[0079] The polymer (A) may also be at least one polymer selected from the group consisting of a polyimide precursor and a polyimide that is an imide derivative of the polyimide precursor. In addition to the repeating units (a1), (a2), (a2'), and (a3) ​​mentioned above, the polyimide precursor also has a repeating unit (a4) as shown in the following formula (4).

[0080]

[0081] In formula (4) above, X4 represents a tetravalent organic group, and Y4 represents a divalent organic group. R and Z have the same meanings as R and Z in formula (1) above. Among them, Y4 represents a structure other than the divalent organic group with the group "-N(D)- (D represents a carbamate protecting group)" in the molecule, having 6 to 30 carbon atoms other than D, and the divalent organic group shown in formula (O2) above. Furthermore, when X4 has the same meaning as the tetravalent organic group shown in formula (g) above, Y4 represents a structure other than the divalent organic group shown in formula (H) above and the divalent organic group shown in formula (O) above.

[0082] As a specific example of X4, the above X can be listed. 2’ The example shown is a tetravalent organic group. From the viewpoint of obtaining the good effects of the present invention, X4 is preferably a tetravalent organic group shown in formula (g) above, or a tetravalent organic group shown in any one of formulas (X-1) to (X-25) above, and more preferably a tetravalent organic group shown in formula (g) above.

[0083] As specific examples of divalent organic groups of Y4, in addition to the divalent organic groups exemplified in the above formulas (H) and (O), divalent organic groups derived from the diamines described below (divalent organic groups formed by removing two amino groups from a diamine) can also be listed.

[0084] 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane; diamines having photo-oriented groups, such as those shown in formulas (g-1) to (g-9); diamines having urea bonds, such as those shown in formulas (u-1) to (u-3) (wherein, the diamine does not have an intramolecular carbamate protecting group); diamines having amide bonds, such as those shown in formulas (u-4) to (u-7) (wherein, the diamine does not have an intramolecular carbamate protecting group); structures having at least one nitrogen-containing atom (hereinafter also referred to as nitrogen-containing structures) formed by at least one of the group consisting of a heterocycle, a secondary amino group, and a tertiary amino group containing a nitrogen atom. Atomic structure. Among them, the above-mentioned secondary and tertiary amino groups are diamines (where the amino group is not bonded to a carbamate protecting group); 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol; 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, or diamine compounds of formulas (3b-1) to (3b-4) below, etc., having a carboxyl group; 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 4,4'-diaminobenzophenone, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indane-5-amine 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; diamines with photopolymerizable groups at the ends, such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline; diamines with steroidal skeletons, such as cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanostane 3,6-bis(4-aminobenzoyloxy)cholestane; and diamines with steroidal skeletons, such as those in formulas (V-1) to (V-6). The diamines shown; diamines having siloxane bonds, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; diamines having an oxazoline ring structure, such as (Ox-1) and (Ox-2); diamines having free radical polymerization initiator functions, such as 1-(4-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylacetone, 2-(4-(2-hydroxy-2-methylpropionyl)phenoxy)ethyl ester of 3,5-diaminobenzoic acid, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, and other diamines with free radical polymerization initiator functions; divalent organic groups derived from diamines; and any one of the groups shown in formulas (Y-1) to (Y-167) as described in WO2018 / 117239.

[0085]

[0086]

[0087] In the above equation (3b-1), A 1 The values ​​represent single bonds, -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-. Each of m1 and m2 is independently 0 to 4, and m1+m2 is 1 to 4.

[0088] In equation (3b-2) above, m3 and m4 are each independently 1 to 5. In equation (3b-3) above, A 2 This represents a straight-chain or branched alkyl group with 1 to 5 carbon atoms, where m5 is 1 to 5. In the above formula (3b-4), A 3 and A 4 Each 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-, with m6 ranging from 1 to 4.

[0089]

[0090] In the above equations (V-1)~(V-6), X v1 ~X v4 X p1 ~X p2 Each can be represented independently as -(CH2) a -(a is 1~15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-, X v5 This represents -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-. X a Represents single bonds, -O-, -NH-, -O-(CH2). m -O- (m = 1–6), -C(CH3)2-, -CO-, -(CH2) m -(m = 1–6), -SO2-, -O-C(CH3)2-, -CO-(CH2) m -(m is 1~6), -NH-(CH2) m -(m is 1~6), -SO2-(CH2)m -(m represents 1~6), -CONH-(CH2) m -(m is 1~6), -CONH-(CH2) m -NHCO- (m is 1~6), -COO- (CH2) m -OCO- (m = 1–6), -CONH-, -NH- (CH2) m -NH- (m represents 1 to 6), or -SO2- (CH2) m -SO2- (m is 1~6), R v1 ~R v4 R 1a ~R 1b Each of the following can be independently represented as an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. k may optionally be the same or different.

[0091]

[0092] Examples of nitrogen-containing heterocycles include: pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, isoquinoline, naphthidine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, and cyclohexylimine. Pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, or acridine are preferred.

[0093] Diamines having a nitrogen-containing structure may optionally have secondary and tertiary amino groups, for example, represented by the following formula (n).

[0094]

[0095] In the above formula (n), R represents a monovalent hydrocarbon group with 1 to 10 hydrogen atoms or carbon atoms. "*1" indicates a bond bonded to the hydrocarbon group. Examples of monovalent hydrocarbon groups such as R in the above formula (n) include: alkyl groups such as methyl, ethyl, and propyl; cycloalkyl groups such as cyclohexyl; and aryl groups such as phenyl and methylphenyl. R is preferably a hydrogen atom or a methyl group.

[0096] Specific examples of diamines having a nitrogen-containing structure include: 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, compounds represented by formulas (Dp-1) to (Dp-8) below, or compounds represented by formulas (z-1) to (z-13) below.

[0097]

[0098]

[0099] From the viewpoint of achieving the desired effects of the present invention, polymer (A) preferably comprises the sum of the repeating unit (a1) and the imidized structural units of the repeating unit (a1) in a proportion of 10 mol% to 100 mol% of all repeating units, and more preferably comprises the sum in a proportion of 15 mol% to 100 mol% of all repeating units. It should be noted that the sum here also includes cases where either the repeating unit (a1) or the imidized structural units of the repeating unit (a1) is 0 mol%. As referred to below as a sum, it also includes cases where one or more constituent unit elements are 0 mol%.

[0100] When polymer (A) contains repeating units other than repeating unit (a1) and imidized structural units of repeating unit (a1), it is preferable that polymer (A) contains the sum of repeating unit (a1) and imidized structural units of repeating unit (a1) at 10 mol% to 95 mol% of all repeating units. Polymer (A) preferably contains the sum of repeating unit (a1) and imidized structural units of repeating unit (a1) at 95 mol% or less of all repeating units, more preferably at 90 mol% or less of all repeating units, and even more preferably at 80 mol% or less of all repeating units. Furthermore, polymer (A) preferably contains the sum of repeating unit (a1) and imidized structural units of repeating unit (a1) at 10 mol% or more of all repeating units, and more preferably at 15 mol% or more of all repeating units.

[0101] From the viewpoint of obtaining the good effects of the present invention, polymer (A) preferably comprises at least 5 mol% of the total repeating units, including the sum of repeating unit (a2) and the imidized structural units of repeating unit (a2), more preferably at least 10 mol% of the total repeating units, and even more preferably at least 20 mol% of the total repeating units. On the other hand, it is preferable that the total is less than 90 mol% of the total repeating units, and more preferably at least 85 mol% of the total repeating units. Furthermore, from the viewpoint of obtaining the good effects of the present invention, polymer (A) preferably comprises between 10 mol% and 90 mol% of the total repeating units, including the sum of repeating unit (a2) and the imidized structural units of repeating unit (a2).

[0102] From the viewpoint of obtaining the desired effects of the present invention, in polymer (A), the sum of repeating units (a1), repeating units (a2), and their imidized structural units is preferably 10 mol% or more of all repeating units, more preferably 20 mol% or more of all repeating units. When polymer (A) contains repeating units other than repeating units (a1), repeating units (a2), and their imidized structural units, the sum of repeating units (a1), repeating units (a2), and their imidized structural units is preferably 95 mol% or less, more preferably 90 mol% or less of all repeating units.

[0103] When polymer (A) comprises at least one of repeating unit (a2') and imidized structural units of repeating unit (a2'), from the viewpoint of obtaining the good effects of the present invention, polymer (A) preferably comprises the sum of repeating unit (a2') and imidized structural units of repeating unit (a2') in a proportion of 1 mol% to 50 mol% of all repeating units, more preferably the sum of the above-mentioned amount in a proportion of 1 mol% to 40 mol% of all repeating units, and even more preferably the sum of the above-mentioned amount in a proportion of 1 mol% to 30 mol% of all repeating units. When polymer (A) comprises at least one of repeating unit (a1) and its imidized structural units, and at least one of repeating unit (a2) and its imidized structural units, the sum of repeating unit (a2') and imidized structural units of repeating unit (a2') is preferably 5 mol% or more, more preferably 10 mol% or more.

[0104] From the viewpoint of obtaining the good effects of the present invention, the polymer (A) comprises at least one of repeating units (a1) and their imidized structural units, at least one of repeating units (a2) and their imidized structural units, and at least one of repeating units (a2') and their imidized structural units. The sum of the repeating units (a1), (a2), (a2'), and their imidized structural units is preferably 30 mol% or more of all repeating units, more preferably 40 mol% or more of all repeating units. When the polymer (A) comprises repeating units other than repeating units (a1), (a2), (a2'), and their imidized structural units, the sum of the repeating units (a1), (a2), (a2'), and their imidized structural units is preferably 95 mol% or less, more preferably 90 mol% or less.

[0105] In the case where the polymer (A) comprises at least one of the repeating unit (a3) ​​and the imidized structural unit of the repeating unit (a3), from the viewpoint of obtaining the good effects of the present invention, the polymer (A) preferably comprises the sum of the repeating unit (a3) ​​and the imidized structure of the repeating unit (a3) ​​in 1 mol% to 40 mol% of all repeating units, more preferably the sum of the above in 1 mol% to 30 mol% of all repeating units, and even more preferably the sum of the above in 1 mol% to 25 mol% of all repeating units.

[0106] The polymer (A) optionally includes repeating units (a2'), repeating units (a3), and their imidized structural units.

[0107] When the polymer (A) contains at least one of the above-described repeating unit (a4) and its imidized structural unit, from the viewpoint of obtaining the good effects of the present invention, it is preferable that the polymer (A) is composed of at least one of the repeating unit (a4) and its imidized structural unit, where Y4 is a divalent organic group without a side chain structure having 4 or more carbon atoms.

[0108] As divalent organic groups that do not have a side chain structure with 4 or more carbon atoms, examples of divalent organic groups derived from the following diamines are listed. These diamines are selected from the group consisting of diamines obtained by removing 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,N-diallyl aniline, the diamines having a steroidal skeleton, the diamines shown in formulas (V-1) to (V-6), 1-(4-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylacetone, 2-(4-(2-hydroxy-2-methylpropionyl)phenoxy)ethyl 3,5-diaminobenzoic acid, N-phenyl-3,6-diaminocarbazole, and the diamines shown in (z-4) and (z-6).

[0109] In the case where the polymer (A) comprises at least one of the repeating unit (a4) and the imidized structural unit of the repeating unit (a4), from the viewpoint of obtaining the good effects of the present invention, the polymer (A) preferably comprises the sum of the repeating unit (a4) and the imidized structure of the repeating unit (a4) in 1 mol% to 90 mol% of all repeating units, more preferably the sum in 5 mol% to 70 mol% of all repeating units, and even more preferably the sum in 10 mol% to 30 mol% of all repeating units.

[0110] <Polymer (B)>

[0111] In addition to the polymer (A) described above, the liquid crystal alignment agent of the present invention may also contain a polymer (B) that does not have the repeating unit (a1) described above. It should be noted that polymer (B) may optionally consist of one or more of these repeating units. From the viewpoint of obtaining the best effects of the present invention, polymers (B) can be listed as polymers having at least one repeating unit selected from the group consisting of a repeating unit (b1) shown in the following formula (5) and an imidized structural unit of that repeating unit (b1). Furthermore, the repeating units constituting polymer (B) may consist of one or more of these repeating units.

[0112]

[0113] In the above formula (5), X5 is a tetravalent organic group and Y5 is a divalent organic group. R and Z have the same meaning as R and Z in the above formula (1).

[0114] As the tetravalent organic group in X5 above, examples include tetravalent organic groups derived from aliphatic tetracarboxylic dianhydrides, tetravalent organic groups derived from alicyclic tetracarboxylic dianhydrides, or tetravalent organic groups derived from aromatic tetracarboxylic dianhydrides. Specific examples include the tetravalent organic groups exemplified in X4 above. From the viewpoint of achieving the desired effects of the present invention, and considering the improvement of liquid crystal orientation, the aforementioned aliphatic or alicyclic tetracarboxylic dianhydrides are preferably tetracarboxylic dianhydrides having at least one partial structure selected from the group consisting of cyclobutane ring structures, cyclopentane ring structures, and cyclohexane ring structures. More preferably, X5 is a tetravalent organic group shown in formula (g) above, a tetravalent organic group shown in any one of formulas (X-1) to (X-25) above, a tetravalent organic group shown in formulas (Xa-1) to (Xa-2) above, or a tetravalent organic group shown in formulas (Xr-1) to (Xr-7) above (these are also collectively referred to as specific tetravalent organic groups).

[0115] From the viewpoint of achieving good results of the present invention, polymer (B) preferably contains repeating units in which X5 is the aforementioned specific tetravalent organic group at least 5 mol% of all repeating units contained in polymer (B), and more preferably contains repeating units in which 10 mol% or more of all repeating units contained in polymer (B) are included.

[0116] As divalent organic groups in Y5 above, examples of divalent organic groups exemplified in Y4 above can be listed. From the viewpoint of minimizing residual DC residue, polymer (B) is preferably a polymer containing repeating units, wherein Y5 is a repeating unit derived from diamines having urea bonds, diamines having amide bonds, diamines having nitrogen-containing structures, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, diamines having carboxyl groups, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, p-phenylenediamine, and m-phenylenediamine (these are also collectively referred to as specific divalent organic groups).

[0117] From the viewpoint of improving transmittance, polymer (B) is more preferably having two or more repeating units as shown in the above formula (5), including repeating units of Y5 having a divalent organic group derived from the above-mentioned diamine having a urea bond, the above-mentioned diamine having an amide bond, or the above-mentioned diamine having a structure containing a nitrogen atom, and repeating units of Y5 having a divalent organic group derived from diamines other than those mentioned above.

[0118] From the viewpoint of minimizing residual DC, polymer (B) may contain repeating units in which Y5 is the aforementioned specific divalent organic group, comprising at least 1 mol% of all repeating units contained in polymer (B), preferably at least 5 mol% of all repeating units contained in polymer (B), more preferably at least 10 mol% of all repeating units contained in polymer (B), and even more preferably at least 20 mol% of all repeating units contained in polymer (B).

[0119] From the viewpoint of minimizing residual DC, the content ratio of polymer (A) to polymer (B) (mass ratio of polymer (A) to polymer (B)) is preferably 10 / 90 to 90 / 10, more preferably 20 / 80 to 90 / 10, and even more preferably 20 / 80 to 80 / 20.

[0120] <Methods for manufacturing polymer (A) and polymer (B)>

[0121] Polyimide precursors of polymers (A) and (B) in this invention, namely polyamic acid esters, polyamic acids, and polyimides as their imides, can be synthesized, for example, by known methods as described in WO2013 / 157586.

[0122] Specifically, the polymer is synthesized by reacting a diamine component with a tetracarboxylic acid derivative component in a solvent via a (condensation) reaction. Examples of the aforementioned tetracarboxylic acid derivative component include tetracarboxylic dianhydride or its derivatives (tetracarboxylic acid dihalides, tetracarboxylic acid diesters, or tetracarboxylic acid diester dihalides). If a portion of polymer (A) or (B) contains an ammonium acid structure, for example, a polymer having an ammonium acid structure (polyamic acid) is obtained by reacting the tetracarboxylic dianhydride component with the diamine component. The solvent is not particularly limited as long as it dissolves the resulting polymer.

[0123] The diamine component and the tetracarboxylic acid derivative component used to obtain the polyimide precursor of polymer (A) correspond to the repeating units shown in the above formulas (1), (2), (2'), (3), and (4) of polymer (A), respectively, and are selected in such a way that the structure of the above repeating units can be obtained.

[0124] For example, in the case of having a repeating unit as shown in formula (1) of polymer (A), as a diamine component, a diamine having a structure of -N(Z)-Y1-N(Z)- (the definitions of Y1 and Z are the same as above) is used (hereinafter also referred to as a specific diamine). In addition, as a tetracarboxylic acid derivative component, a tetracarboxylic acid derivative having a structure of the following formula (g) (the definitions of R1 to R4 are the same as above) is used.

[0125]

[0126] In the case of obtaining a polyimide precursor of polymer (A) having repeating units as shown in formula (2), formula (2'), formula (3), and formula (4) of polymer (A), the diamine component and the tetracarboxylic acid derivative component used are selected according to the diamine and the tetracarboxylic acid derivative used in the case of obtaining a polyimide precursor having repeating units as shown in formula (1) above.

[0127] Furthermore, the diamine component and the tetracarboxylic acid derivative component used to obtain the polyimide precursor of polymer (B) are selected in such a way that the polymer (B) has the repeating unit structure shown in the above formula (5). That is, as the diamine component, a diamine having the structure -N(Z)-Y5-N(Z)- (the definitions of Y5 and Z are the same as above) is used, and as the tetracarboxylic acid derivative component, a tetracarboxylic acid derivative having the structure X5 (the definition of X5 is the same as above) is used.

[0128] Specific examples of solvents used to react the diamine component with the tetracarboxylic acid derivative component include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolinone. 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] can be used.

[0129]

[0130] (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 This refers to alkyl groups having 1 to 4 carbon atoms.

[0131] These solvents may be used alone or in combination. Furthermore, even solvents that do not dissolve polymers may be mixed with the aforementioned solvents to the extent that the resulting polymer does not precipitate.

[0132] When the diamine component reacts with the tetracarboxylic acid derivative component in a solvent, the reaction can be carried out at any concentration, preferably 1% to 50% by mass, more preferably 5% to 30% by mass. Alternatively, the reaction can be carried out at a high concentration initially, followed by the addition of solvent.

[0133] In the reaction, the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic acid derivative component (total molar number of the tetracarboxylic acid derivative component / total molar number of the diamine component) is preferably 0.8 to 1.2. Similar to conventional polycondensation reactions, the closer this molar ratio is to 1.0, the larger the molecular weight of the resulting polymer (A) and polymer (B).

[0134] Polyamates can be obtained, for example, by the following methods: [I] reacting the polyamic acid obtained in the above methods with an esterifying agent; [II] reacting a tetracarboxylic acid diester with a diamine; [III] reacting a tetracarboxylic acid diester dihalide with a diamine, etc.

[0135] Methods for obtaining polyimide include: thermal imidization, which involves directly heating the solution containing polyimide precursors such as polyamic acid and polyamic acid ester obtained in the above reaction; or catalytic imidization, which involves adding a catalyst to the above solution.

[0136] The polyimide in the polymer (A) of the present invention is formed by partially or completely cyclizing the repeating units of the aforementioned polyimide precursor. In the aforementioned polyimide, the imidization rate is preferably 20% to 95%, more preferably 30% to 95%, and even more preferably 50% to 95%.

[0137] <Polymer solution viscosity, molecular weight>

[0138] Regarding the polyamic acid, polyamic acid ester, and polyimide in the polymer (A) of the present invention, when prepared into a solution with a concentration of 10% to 15% by mass, for example, from a workability point of view, a polymer having a solution viscosity of 10 mPa·s to 1000 mPa·s is preferred, but there is no particular limitation. It should be noted that the solution viscosity (mPa·s) of the above-mentioned polymer is a value measured using an E-type rotational viscometer at 25°C for a polymer solution with a concentration of 10% to 15% by mass prepared using a good solvent (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) using the polymer.

[0139] The weight-average molecular weight (Mw) of the polyamic acid, polyamic acid ester, and polyimide, as determined by gel permeation chromatography (GPC), converted from polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. Furthermore, the molecular weight distribution (Mw / Mn) shown by the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC is preferably 15 or less, more preferably 10 or less. Within this molecular weight range, good orientation and stability of the liquid crystal display element can be ensured.

[0140] <End-capping agent>

[0141] When synthesizing polymers (A) and (B) of this invention, they can also be used together with the tetracarboxylic acid derivative component and the diamine component as described above, using a suitable capping agent to prepare a capped polymer. The capped polymer has the effect of increasing the film hardness of the liquid crystal alignment film obtained from the coating and improving the adhesion properties between the sealant and the liquid crystal alignment film.

[0142] Examples of the ends of polymers (A) and (B) in this invention include amino, carboxyl, anhydride, or derivatives thereof. Amino, carboxyl, anhydride, and isocyanate groups can be obtained through conventional condensation reactions or by end-capping with end-capping agents, for example, the following end-capping agents can be used in the same manner.

[0143] 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, and n-octylamine; monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, 2-acryloyloxyethyl isocyanate, and 2-methacryloyloxyethyl isocyanate; and isothiocyanate compounds such as ethyl isothiocyanate and allyl isothiocyanate.

[0144] Regarding the proportion of the capping agent used, it is preferably 0.01 to 20 moles, more preferably 0.01 to 10 moles, relative to 100 moles of the total diamine components used.

[0145] <Liquid Crystal Alignment Agent>

[0146] The liquid crystal alignment agent of the present invention contains a polymer (A) and a polymer (B) as needed. In addition to polymer (A) and polymer (B), the liquid crystal alignment agent of the present invention may also contain other polymers. Specific examples of other polymers include polymers selected from the group consisting of 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.

[0147] Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, 2000, 3000 (manufactured by Cray Valley), and GSM301 (manufactured by Gifu Shellac Manufacturing Co., Ltd.); 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 Ashland). Other polymers may be used alone or in combination of two or more. The proportion of other polymers relative to 100 parts by mass of the total polymers contained in the liquid crystal alignment agent is preferably 90 parts by mass or less, more preferably 10 to 90 parts by mass, and even more preferably 20 to 80 parts by mass.

[0148] Liquid crystal alignment agents are used to produce liquid crystal alignment films, and from the viewpoint of forming a uniform thin film, they are adopted in the form of a coating liquid. In the liquid crystal alignment agent of the present invention, a coating liquid containing the aforementioned polymer component and organic solvent is also preferred. In this case, the concentration of the polymer in the liquid crystal alignment agent can be appropriately varied according to the desired thickness of the coating film. From the viewpoint of forming a uniform and defect-free coating film, the concentration of the polymer in the liquid crystal alignment agent is preferably 1% by mass or more, and from the viewpoint of the storage stability of the solution, it is preferably 10% by mass or less. A particularly preferred polymer concentration is 2% to 8% by mass.

[0149] The organic solvent contained in liquid crystal alignment agents is not particularly limited as long as it can uniformly dissolve the polymer components. Specific examples include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllacticamide, 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, and 3-methoxy-N,N-dimethyl... Acrylamide, 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"). 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.

[0150] Furthermore, the organic solvent contained in the liquid crystal alignment agent is preferably a mixed solvent that, in addition to the solvents mentioned above, also incorporates a solvent (also known as a poor solvent) that improves the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent. 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 based on the coating apparatus, coating conditions, coating environment, etc., of the liquid crystal alignment agent.

[0151] The following are specific examples of the aforementioned undesirable solvents, but are not limited to these examples.

[0152] Examples 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) 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.

[0153] As a poor solvent, 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.

[0154] Preferred combinations of good and bad 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 dipropylene glycol monobutyl ether. Ethers, N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate, N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether, N,N-dimethyl lactamide and ethylene glycol monobutyl ether, N,N-dimethyl lactamide and propylene glycol diacetate, N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone and diethylene glycol monoethyl ether and butyl cellosolve acetate, N-methyl-2-pyrrolidone and diethylene glycol monomethyl ether and butyl cellosolve acetate, N...N-Dimethyllactic acid and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone and N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone and 4-Hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol dimethyl ether, γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone, γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisobutyl ketone, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisopropyl ether, N-methyl N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisobutylmethanol, N-methyl-2-pyrrolidone and γ-butyrolactone and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone and propylene glycol monobutyl ether and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether and propylene glycol diacetate, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether and diisobutyl ketone, N-ethyl-2-pyrrolidone and γ-butyrolactone and diisobutyl ether Ketones, N-ethyl-2-pyrrolidone and N,N-dimethyllacticamide and diisobutyl ketone, N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate, γ-butyrolactone and ethylene glycol monobutyl ether acetate and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate and propylene glycol dimethyl ether, N-methyl-2-pyrrolidone and 4-methyl-2-pentyl acetate and ethylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and cyclohexyl acetate and diacetone alcohol cyclohexanone and propylene glycol monomethyl ether, cyclopentanone and propylene glycol monomethyl ether, N-methyl-2-pyrrolidone and cyclohexanone and propylene glycol monomethyl ether, etc.

[0155] The liquid crystal alignment agent of the present invention may be supplemented with components other than polymer components and organic solvents (hereinafter also referred to as additive components). Examples of such additive components include: adhesion promoters for improving the adhesion between the liquid crystal alignment film and the substrate, and the adhesion between the liquid crystal alignment film and the sealant; compounds for improving the strength of the liquid crystal alignment film (hereinafter also referred to as crosslinking compounds); compounds for promoting imidization; dielectrics for adjusting the dielectric constant and resistance of the liquid crystal alignment film; and conductive materials.

[0156] From the viewpoint of exhibiting good resistance to AC remnants and significant improvement in film strength, the following compounds can be listed as crosslinking compounds: compounds having at least one group selected from the group consisting of ethylene oxide, oxetane, protected isocyanate group, protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Michaelis acid structure, a cyclic carbonate group, and a group represented by formula (d) below, or compounds represented by formula (e) below.

[0157]

[0158] In formula (d) above, R2 and R3 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH". In formula (e) above, A represents an organic group having an aromatic ring with a (m+n) valence, and R and R' each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, where m is 1 to 6 and n is 0 to 4. Any hydrogen atom in the aromatic ring may optionally be substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkenyl group having 2 to 10 carbon atoms, or a fluoroalkoxy group having 1 to 10 carbon atoms.

[0159] Specific examples of compounds containing ethylene oxide include compounds described in Japanese Patent Application Publication No. 10-338880

[0037] , compounds with a triazine ring skeleton described in WO2017 / 170483, and other compounds containing two or more ethylene oxide groups. These may include nitrogen-containing compounds such as N,N,N',N'-tetracyclooxypropylmethylenediamine, 1,3-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetracyclooxypropyl-p-phenylenediamine, and compounds shown in formulas (r-1) to (r-3) below.

[0160]

[0161] Specific examples of compounds having oxetane groups include compounds having two or more oxetane groups as described in

[0170] to

[0175] of WO2011 / 132751.

[0162] Specific examples of compounds having protected isocyanate groups include compounds having two or more protected isocyanate groups as described in Japanese Patent Application Publication No. 2014-224978

[0046] to

[0047] , and compounds having three or more protected isocyanate groups as described in WO2015 / 141598

[0119] to

[0120] . These can be compounds represented by the formulas (bi-1) to (bi-3) below.

[0163]

[0164] As a specific example of a compound having a protected isothiocyanate group, compounds having two or more protected isothiocyanate groups as described in Japanese Patent Application Publication No. 2016-200798 can be cited.

[0165] As a specific example of a compound having a group containing an oxazoline ring structure, the compound containing two or more oxazoline structures described in Japanese Patent Application Publication No. 2007-286597

[0115] can be cited.

[0166] As a specific example of a compound having a group containing a Michaelis acid structure, compounds having two or more Michaelis acid structures as described in WO2012 / 091088 can be cited.

[0167] Specific examples of compounds having cyclic carbonate groups include the compounds described in WO2011 / 155577.

[0168] Examples of alkyl groups with 1 to 3 carbon atoms, such as R2 and R3, which are groups shown in formula (d) above, include methyl, ethyl, propyl, and isopropyl.

[0169] Specific examples of compounds having the groups shown in formula (d) above include compounds having two or more groups shown in formula (d) as described in WO2015 / 072554, Japanese Patent Application Publication No. 2016-118753

[0058] , and compounds described in Japanese Patent Application Publication No. 2016-200798, which can be compounds shown in formulas (hd-1) to (hd-8) below.

[0170]

[0171] The (m+n) valence organic group with an aromatic ring in A of formula (e) above can be exemplified by an (m+n) valence aromatic hydrocarbon group with 6 to 30 carbon atoms, an (m+n) valence organic group formed by direct or linked groups of an aromatic hydrocarbon group with 6 to 30 carbon atoms, or an (m+n) valence group with an aromatic heterocycle. Examples of the aforementioned aromatic hydrocarbon groups include benzene and naphthalene. Examples of aromatic heterocycles include those within the structures shown in the examples of nitrogen-containing heterocycles above, represented by pyridine rings. Examples of linked groups include alkylene groups with 1 to 10 carbon atoms, -NR- (where R is a hydrogen atom or an alkyl group with 1 to 5 carbon atoms), groups obtained by removing one hydrogen atom from the aforementioned alkylene groups, divalent or trivalent cyclohexane rings, etc. It should be noted that any hydrogen atom of the aforementioned alkylene group may optionally be replaced by an alkyl group with 1 to 6 carbon atoms, a fluorine atom, or an organic group such as trifluoromethyl. As alkyl groups with 1 to 5 carbon atoms in R and R' of the above formula (e), specific examples of alkyl groups shown in R1 to R4 of the above formula (1) can be listed.

[0172] As specific examples of formula (e) above, compounds described in WO2010 / 074269 and any of the compounds shown in formulas (e-1) to (e-10) below can be listed.

[0173]

[0174] The compounds illustrated above are examples of crosslinking compounds, but are not limited thereto. For example, compounds disclosed on pages 53

[0105] to 55

[0116] of WO2015 / 060357 can be cited. Furthermore, two or more crosslinking compounds may be optionally combined.

[0175] The content of the crosslinking compound in the liquid crystal alignment agent of the present invention is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, and more preferably 1 to 15 parts by mass from the viewpoint that the crosslinking reaction proceeds and exhibits good resistance to AC image retention.

[0176] Examples of the aforementioned sealing agents include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3- Silane coupling agents including glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, tris(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatepropyltriethoxysilane.

[0177] When using a silane coupling agent, from the viewpoint of exhibiting good resistance to AC image retention, the preferred amount is 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

[0178] As the compound used to promote the imidization described above, it is preferable to be a compound having a basic site (e.g., primary amino group, aliphatic heterocycle (e.g., pyrrolidine skeleton), aromatic heterocycle (e.g., imidazole ring, indole ring), or guanidine group, etc.) (excluding the aforementioned crosslinking compounds and binding aids) or a compound that generates the aforementioned basic site during calcination. More preferably, it is a compound that generates the aforementioned basic site during calcination; specific examples include compounds shown in formulas (B-1) to (B-17) below. Regarding the content of the compound used to promote imidization, it is preferable to be 2 moles or less, more preferably 1 mole or less, and even more preferably 0.5 moles or less, relative to 1 mole of the amic acid or amic acid ester site present in the polymer (A).

[0179]

[0180] (D represents an organic group that is removed by heating, preferably either tert-butoxycarbonyl or 9-fluorenylmethoxycarbonyl. In the presence of multiple D groups, the D groups may optionally be the same as or different from each other.)

[0181] The concentration of solid components in the liquid crystal alignment agent of the present invention (the proportion of the total mass of components other than the solvent in the total mass of the liquid crystal alignment agent) can be appropriately selected considering viscosity, volatility, etc., but is preferably in the range of 1% to 10% by mass.

[0182] The particularly preferred range of solid component concentration varies depending on the method used to coat the liquid crystal alignment agent onto the substrate. As described in step (1) below, methods for coating the liquid crystal alignment agent onto the substrate include, for example, roller coating, spin coating, printing, and inkjet coating. When using roller coating, the solid component concentration is particularly preferably in the range of 4% to 10% by mass. 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, it is particularly preferred to set the solid component concentration to the range of 3% to 9% by mass, thereby setting the solution viscosity to the range of 12 mPa·s to 50 mPa·s. When using inkjet coating, it is particularly preferred to set the solid component concentration to the range of 1% to 5% by mass, thereby setting the solution viscosity to the range of 3 mPa·s to 15 mPa·s. The temperature for preparing the polymer composition is preferably 10°C to 50°C, more preferably 20°C to 30°C.

[0183] <Liquid Crystal Alignment Film>

[0184] The liquid crystal alignment film of the present invention is obtained from the above-mentioned liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used for horizontally aligned or vertically aligned (VA type) liquid crystal alignment films, wherein it is suitable for horizontally aligned liquid crystal display elements such as IPS driving mode or FFS driving mode. Furthermore, it is more preferably used for liquid crystal alignment films for photo-alignment processing methods. In addition, it can be effectively applied to various technical applications, such as liquid crystal alignment films other than those mentioned above (liquid crystal alignment films for 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), or other applications, such as protective films (e.g., protective films for color filters), spacer films, interlayer insulating films, anti-reflective films, wiring coating films, antistatic films, motor insulating films (gate insulating films for flexible displays), etc.

[0185] The liquid crystal alignment film of the present invention can be manufactured, for example, by a method including the following steps (1) to (3), preferably including steps (1) to (4).

[0186] <Process (1): The process of coating the liquid crystal alignment agent onto the substrate>

[0187] The liquid crystal alignment agent of the present invention is applied to one side of a substrate having a patterned transparent conductive film using a suitable coating method such as a roll coating, spin coating, printing, or inkjet coating. Here, the substrate is not particularly limited as long as it is a highly transparent substrate; it can also 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 in this case, the electrodes can be made of light-reflecting materials such as aluminum. Moreover, in the manufacture of liquid crystal display elements using IPS or FFS driving methods, a substrate having electrodes composed of a patterned comb-shaped transparent conductive film or metal film and an opposing substrate without electrodes are used.

[0188] Methods for coating a liquid crystal alignment agent onto a substrate and forming a film include screen printing, offset printing, flexographic printing, inkjet printing, and spraying. Among these, inkjet printing is a preferred method for coating and forming a film.

[0189] <Process (2): The process of firing the coated liquid crystal alignment agent>

[0190] Step (2) is a step of forming a film by firing the liquid crystal alignment agent coated on the substrate. After the liquid crystal alignment agent is coated on the substrate, the solvent can be evaporated by heating units such as heating plates, thermal cycling ovens, or IR (infrared) ovens, or thermal imidization of polyamic acid or polyamic acid esters 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. As for the firing temperature, it can be performed at, for example, 40°C to 180°C. From the viewpoint of shortening the process, it can be performed at 40°C to 150°C. As for the firing time, there is no particular limitation, and examples include 1 minute to 10 minutes, preferably 1 minute to 5 minutes. In the case of thermal imidization of polyamic acid or polyamic acid esters, after the above firing step, the firing step can be performed at, for example, a temperature range of 150°C to 300°C, preferably 150°C to 250°C. There is no particular limitation on the firing time, but it can be listed as 5 minutes to 40 minutes, with 5 minutes to 30 minutes being the preferred firing time.

[0191] If the film after firing is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, 5nm to 300nm is preferred, and 10nm to 200nm is more preferred.

[0192] <Step (3): The step of oriented treatment of the film obtained in step (2)>

[0193] Step (3) is a step of aligning the film obtained in step (2) as needed. That is, in horizontally aligned liquid crystal display elements such as IPS driving mode or FFS driving mode, the above-mentioned coating is subjected to alignment capability imparting treatment. On the other hand, in vertically aligned liquid crystal display elements such as VA mode or PSA mode, the formed coating can be used directly as a liquid crystal alignment film, but the above-mentioned coating can also be subjected to alignment capability imparting treatment. As an alignment treatment method for liquid crystal alignment film, the rubbing treatment method and the photo-alignment treatment method can be listed, and the photo-alignment treatment method is more preferred. 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 heating treatment at a temperature of 150°C 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 100nm to 800nm ​​can be used. Among them, ultraviolet light with a wavelength of 100nm to 400nm is preferred, and ultraviolet light with a wavelength of 200nm to 400nm is more preferred.

[0194] The preferred radiation dose is 1 mJ / cm². 2 ~10000mJ / cm 2 More preferably 100 mJ / cm 2 ~5000mJ / cm 2 Further preferred is 100 mJ / cm 2 ~1500mJ / cm 2 The preferred value is 100 mJ / cm. 2 ~1000mJ / cm 2 A further preferred value is 100 mJ / cm 2 ~400mJ / cm 2 Previously, when using liquid crystal alignment agents, the light irradiation dose during the alignment process was 100 mJ / cm². 2 ~5000mJ / cm 2 However, in the liquid crystal alignment agent of the present invention, even if the amount of light irradiation during the alignment process is reduced, a liquid crystal alignment film that suppresses the deviation (non-uniformity) of liquid crystal alignment within the liquid crystal alignment film surface can be obtained.

[0195] Furthermore, to improve liquid crystal alignment when irradiated with radiation, the substrate having the above-described film can be heated at 50°C to 250°C while being irradiated with radiation. The liquid crystal alignment film fabricated as described above enables the liquid crystal molecules to be stably aligned in a fixed direction.

[0196] 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.

[0197] The solvent used in the above-mentioned contact treatment is not particularly limited as long as it dissolves the decomposition products generated from the film due to 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. Among these, considering versatility and solvent safety, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred. More preferably, water, 1-methoxy-2-propanol, or ethyl lactate are preferred. One solvent may be used, or a combination of two or more may be used.

[0198] <Step (4): A step of heating the film that has undergone orientation treatment in step (3) at 50°C to 300°C>

[0199] The above-mentioned radiation-irradiated coating can also be subjected to heat treatment. The preferred temperature for the heat treatment is 50°C to 300°C, more preferably 120°C to 250°C. The preferred heat treatment time is 1 minute to 30 minutes.

[0200] Liquid crystal display element

[0201] The liquid crystal display element of the present invention includes the liquid crystal alignment film of the present invention, and is manufactured as described below. Two substrates having the liquid crystal alignment film obtained as described above are prepared, and liquid crystal is disposed between the two substrates arranged opposite each other. Specifically, the following two methods can be listed.

[0202] 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. After the liquid crystal composition is filled into the cell gap defined by the substrate surface and the sealant through an injection hole and comes into contact with the film surface, the injection hole is sealed.

[0203] The second method is known as the ODF (One Drop Fill) method. In this method, 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 locations on the surface of the alignment film. Next, the other substrate is bonded with the alignment films facing each other, and the liquid crystal composition is pushed across the entire surface of the substrate, making contact with the film surface. Finally, the entire surface of the substrate is irradiated with UV light to cure the sealant.

[0204] In either of the above methods, it is ideal to further heat the liquid crystal composition to a temperature at which it becomes isotropic, and then slowly cool it to room temperature, thereby removing the flow orientation during liquid crystal filling.

[0205] It should be noted that when the coating has been rubbed, the two substrates are arranged opposite each other at a specified angle, such as orthogonal or antiparallel, with the rubbing directions of each coating.

[0206] As a sealant, epoxy resin containing a curing agent and alumina spheres as spacers can be used, for example. Nematic liquid crystals and smectic liquid crystals can be cited as examples, with nematic liquid crystals being preferred.

[0207] There are no particular limitations on the liquid crystal composition described above; various liquid crystal compositions containing at least one liquid crystal compound (liquid crystal molecule) and having positive or negative dielectric anisotropy can be used. It should be noted that, hereinafter, liquid crystal compositions with positive dielectric anisotropy will be referred to as positive liquid crystals, and liquid crystal compositions with negative dielectric anisotropy will be referred to as negative liquid crystals.

[0208] Examples of liquid crystal compositions include nematic liquid crystal compositions, lamellar liquid crystal compositions, and cholesteric liquid crystal compositions, with nematic liquid crystal compositions being preferred.

[0209] The liquid crystal composition described above may contain liquid crystal compounds having 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. It may also contain compounds having two or more rigid sites (mesocrystalline skeletons) exhibiting liquid crystal properties within the molecule (e.g., a bimesocrystalline compound formed by two rigid biphenyl structures or terphenyl structures linked by alkyl groups).

[0210] From the viewpoint of improving liquid crystal orientation, the above-mentioned liquid crystal composition can be further supplemented with additives. Such additives include: photopolymerizable monomers such as compounds with polymerizable groups; optically active compounds (e.g., S-811 manufactured by Merck Co., Ltd.); antioxidants; ultraviolet absorbers; pigments; defoamers; polymerization initiators; or polymerization inhibitors, etc.

[0211] Examples of positive liquid crystal displays include Merck's ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081.

[0212] Examples of negative liquid crystals include MLC-6608, MLC-6609, MLC-6610, and MLC-7026-100 manufactured by Merck.

[0213] In addition, as a liquid crystal containing compounds with polymerizable groups, Merck's MLC-3023 can be cited as an example.

[0214] Then, by attaching a polarizer to the outer surface of the liquid crystal cell as needed, a liquid crystal display element can be obtained. Examples of polarizers attached to the outer surface of the liquid crystal cell include polarizers made by clamping a polarizing film called an "H film" that absorbs iodine while stretching and oriented polyvinyl alcohol with a cellulose acetate protective film, or polarizers made of the H film itself.

[0215] The IPS substrate, which is a comb electrode substrate used in the 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.

[0216] It should be noted that the FFS substrate, which is the comb electrode substrate used in the 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.

[0217] Figure 1 This is a schematic cross-sectional view showing an example of an IPS mode lateral electric field liquid crystal display element having a liquid crystal alignment film obtained by the liquid crystal alignment agent of the present invention.

[0218] 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 shape, 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 the liquid crystal alignment film of the present invention. Similarly, the liquid crystal alignment film 4c is also the liquid crystal alignment film of the present invention.

[0219] exist Figure 1 In the transverse electric field liquid crystal display element 1, if 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.

[0220] Figure 2This is a schematic cross-sectional view showing an example of a lateral electric field liquid crystal display element having an FFS mode liquid crystal alignment film obtained by the liquid crystal alignment agent of the present invention.

[0221] exist Figure 2 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 2h and a counter 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 shape, and a liquid crystal alignment film 2h formed on the insulating film 2f to cover the linear electrodes 2g. The counter 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 the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4a is also the liquid crystal alignment film of the present invention.

[0222] exist Figure 2 In the transverse electric field liquid crystal display element 1, if 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.

[0223] Example

[0224] The following examples illustrate the invention in further detail, but the invention is not limited thereto. The abbreviations of the compounds and the methods for determining their properties are described below.

[0225] Boc: tert-butoxycarbonyl.

[0226] Fmoc: 9-fluorenylmethoxycarbonyl.

[0227] (Specific diamine)

[0228]

[0229] (Other diamines)

[0230]

[0231] (Tetracarboxylic acid dianhydride)

[0232]

[0233] (additive)

[0234]

[0235] (solvent)

[0236] NMP: N-methyl-2-pyrrolidone.

[0237] BCS: Ethylene glycol monobutyl ether.

[0238] (Determination of molecular weight)

[0239] The molecular weight was determined using a room-temperature gel permeation chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko Corporation) and chromatographic columns (KD-803, KD-805) (manufactured by Showa Denko Corporation) under the following conditions.

[0240] Column temperature: 50℃.

[0241] Eluent: N,N-dimethylformamide (as additives, lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, phosphoric acid / anhydrous crystals (orthophosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L).

[0242] Flow rate: 1.0 ml / min.

[0243] Standard samples used for calibration curve preparation: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000 and 30,000) (manufactured by Tosoh) and polyethylene glycol (molecular weight: approximately 12,000, 4,000 and 1,000) (manufactured by Polymer Laboratories).

[0244] (Viscosity measurement)

[0245] The measurements were performed using a TVE-22H type E viscometer (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL and a conical rotor TE-1 (1°34', R24), at a temperature of 25°C.

[0246] <Polymer Synthesis>

[0247] (Synthesis example 1)

[0248] A1 (0.811 g, 7.50 mmol), WA-1 (1.02 g, 7.50 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), B1 (6.39 g, 28.5 mmol), and NMP (93.9 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (A-1) with a solid content of 12% by mass (viscosity: 401 mPa·s). The number-average molecular weight (Mn) of this polyamic acid was 12939, and the weight-average molecular weight (Mw) was 38921.

[0249] (Synthesis example 2)

[0250] To a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, WA-1 (2.04 g, 15.0 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), B1 (6.39 g, 28.5 mmol), and NMP (95.5 g) were added. The mixture was stirred at 40 °C for 20 hours to obtain a 12% by mass solution of polyamic acid (A-2) (viscosity: 373 mPa·s). The Mn of this polyamic acid was 11813, and the Mw was 37191.

[0251] (Synthesis example 3)

[0252] A1 (0.811 g, 7.50 mmol), WA-2 (0.946 g, 7.50 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), B1 (6.46 g, 28.8 mmol), and NMP (93.9 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyamic acid (A-3) solution with a solid content of 12% by mass (viscosity: 399 mPa·s). The Mn of this polyamic acid was 12191, and the Mw was 38811.

[0253] (Synthesis Example 4)

[0254] A 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube was filled with WA-2 (1.89 g, 15.0 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), B1 (6.46 g, 28.8 mmol), and NMP (94.9 g). The mixture was stirred at 40 °C for 20 hours to obtain a 12% by mass solution of polyamic acid (A-4) (viscosity: 369 mPa·s). The polyamic acid had a Mn of 11304 and a Mw of 37191.

[0255] (Synthesis Example 5)

[0256] A1 (0.811 g, 7.50 mmol), WA-3 (1.04 g, 7.50 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), B1 (6.39 g, 28.5 mmol), and NMP (94.1 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyamic acid (A-5) solution with a solid content of 12% by mass (viscosity: 372 mPa·s). The Mn of this polyamic acid was 12492, and the Mw was 40113.

[0257] (Synthesis Example 6)

[0258] WA-3 (2.07 g, 15.0 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), B1 (6.39 g, 28.5 mmol), and NMP (95.7 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyamic acid (A-6) solution with a solid content of 12% by mass (viscosity: 385 mPa·s). The Mn of this polyamic acid was 13012, and the Mw was 40200.

[0259] (Synthesis Example 7)

[0260] A1 (0.811 g, 7.50 mmol), WA-4 (1.26 g, 7.50 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), B1 (6.39 g, 28.5 mmol), and NMP (95.7 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyamic acid (A-7) solution with a solid content of 12% by mass (viscosity: 370 mPa·s). The Mn of this polyamic acid was 11028, and the Mw was 37190.

[0261] (Synthesis Example 8)

[0262] WA-4 (2.52 g, 15.0 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), B1 (6.39 g, 28.5 mmol), and NMP (99.0 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyamic acid (A-8) solution with a solid content of 12% by mass (viscosity: 360 mPa·s). The Mn of this polyamic acid was 10221, and the Mw was 36821.

[0263] (Synthesis Example 9)

[0264] A1 (0.487 g, 4.50 mmol), WA-1 (0.613 g, 4.50 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), A3 (1.92 g, 6.00 mmol), B1 (6.42 g, 28.7 mmol), and NMP (102 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a polyamic acid (A-9) solution with a solid content of 12% by mass (viscosity: 409 mPa·s). The Mn of this polyamic acid was 13001, and the Mw was 40012.

[0265] (Synthesis Example 10)

[0266] To a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, WA-1 (1.23 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), A3 (1.92 g, 6.00 mmol), B1 (6.46 g, 28.8 mmol), and NMP (104 g) were added. The mixture was stirred at 40 °C for 20 hours to obtain a polyamic acid (A-10) solution with a solid content of 12% by mass (viscosity: 415 mPa·s). The Mn of this polyamic acid was 12948, and the Mw was 40889.

[0267] (Synthesis Example 11)

[0268] A1 (0.487 g, 4.50 mmol), WA-3 (0.622 g, 4.50 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), A3 (1.92 g, 6.00 mmol), B1 (6.42 g, 28.7 mmol), and NMP (102 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (A-11) with a solid content of 12% by mass (viscosity: 419 mPa·s). The Mn of this polyamic acid was 12978, and the Mw was 41048.

[0269] (Synthesis Example 12)

[0270] To a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, WA-3 (1.24 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), A3 (1.92 g, 6.00 mmol), B1 (6.42 g, 28.7 mmol), and NMP (103 g) were added. The mixture was stirred at 40 °C for 20 hours to obtain a polyamic acid (A-12) solution with a solid content of 12% by mass (viscosity: 401 mPa·s). The Mn of this polyamic acid was 11992, and the Mw was 39171.

[0271] (Synthesis Example 13)

[0272] A1 (0.487 g, 4.50 mmol), WA-4 (0.757 g, 4.50 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), A3 (1.92 g, 6.00 mmol), B1 (6.39 g, 28.5 mmol), and NMP (103 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (A-13) with a solid content of 12% by mass (viscosity: 398 mPa·s). The Mn of this polyamic acid was 12091, and the Mw was 42039.

[0273] (Synthesis Example 14)

[0274] To a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, WA-4 (1.51 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), A3 (1.92 g, 6.00 mmol), B1 (6.39 g, 28.5 mmol), and NMP (103 g) were added. The mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (A-14) with a solid content of 12% by mass (viscosity: 366 mPa·s). The Mn of this polyamic acid was 10208, and the Mw was 35029.

[0275] (Synthesis Example 15)

[0276] A6 (4.78 g, 24.0 mmol), A1 (0.649 g, 6.00 mmol), B2 (5.59 g, 28.5 mmol), and NMP (99.2 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature for 5 hours to obtain a 10% by mass solution of polyamic acid (A-15) (viscosity: 200 mPa·s). The Mn of this polyamic acid was 14101, and the Mw was 43911.

[0277] (Synthesis Example 16)

[0278] A5 (5.37 g, 18.0 mmol), A1 (1.30 g, 12.0 mmol), B2 (5.41 g, 27.6 mmol), and NMP (68.5 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature for 5 hours to obtain a solution of polyamic acid (A-16) with a solid content of 15% by mass (viscosity: 751 mPa·s). The Mn of this polyamic acid is 11038, and the Mw is 37102.

[0279] (Synthesis Example 17)

[0280] A5 (7.16 g, 24.0 mmol), A7 (1.19 g, 6.00 mmol), B2 (5.41 g, 27.6 mmol), and NMP (78.0 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature for 5 hours to obtain a solution of polyamic acid (A-17) with a solid content of 15% by mass (viscosity: 761 mPa·s). The Mn of this polyamic acid was 10951, and the Mw was 38322.

[0281] (Synthetic Example 18 (Comparison))

[0282] A1 (1.62 g, 15.0 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.39 g, 6.00 mmol), B1 (6.39 g, 28.5 mmol), and NMP (92.4 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (RA-1).

[0283] [Table 1]

[0284] Synthesis example polyamic acid acid dianhydride Specific diamine Other diamines 1 A-1 B1(100) WA-1(25) A1(25) A2(30) A4(20) 2 A-2 B1(100) WA-1(50) A2(30) A4(20) 3 A-3 B1(100) WA-2(25) A1(25) A2(30) A4(20) 4 A-4 B1(100) WA-2(50) A2(30) A4(20) 5 A-5 B1(100) WA-3(25) A1(25) A2(30) A4(20) 6 A-6 B1(100) WA-3(50) A2(30) A4(20) 7 A-7 B1(100) WA-4(25) A1(25) A2(30) A4(20) 8 A-8 B1(100) WA-4(50) A2(30) A4(20) 9 A-9 B1(100) WA-1(15) A1(15) A2(30) A4(20) A3(20) 10 A-10 B1(100) WA-1(30) A2(30) A4(20) A3(20) 11 A-11 B1(100) WA-3(15) A1(15) A2(30) A4(20) A3(20) 12 A-12 B1(100) WA-3(30) A2(30) A4(20) A3(20) 13 A-13 B1(100) WA-4(15) A1(15) A2(30) A4(20) A3(20) 14 A-14 B1(100) WA-4(30) A2(30) A4(20) A3(20) 15 A-15 B2(100) - A6(80) A1(20) 16 A-16 B2(100) - A1(40) A5(60) 17 A-17 B2(100) - A5(80) A7(20) 18 RA-1 B1(100) - A1(50) A2(30) A4(20)

[0285] <Preparation of Liquid Crystal Alignment Agents>

[0286] (Example 1)

[0287] NMP (9.33 g), BCS (4.00 g), and AD-2 (0.112 g) were added to the polyamic acid (A-1) solution (6.67 g) obtained in Synthesis Example 1, and the mixture was stirred at room temperature for 2 hours to obtain liquid crystal alignment agent (V-1).

[0288] (Examples 2-14)

[0289] The solution of polyamic acid used was set as (A-2) to (A-14), and the operation was the same as in Example 1, thereby obtaining liquid crystal alignment agents (V-2) to (V-14).

[0290] (Example 15)

[0291] To the polyamic acid (A-9) solution (5.30 g) obtained in Synthesis Example 9, a polyamic acid (A-15) solution (9.54 g), NMP (3.78 g), BCS (9.00 g), a 10% mass dilution of NMP1 in AD-1 (0.800 g), and a 1% mass dilution of NMP1 in AD-3 (1.59 g) were added. The mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (V-15).

[0292] (Example 16)

[0293] To the polyamic acid (A-10) solution (5.30 g) obtained in Synthesis Example 10, add the polyamic acid (A-15) solution (9.54 g), NMP (3.78 g), BCS (9.00 g), a 10% mass dilution of NMP1 in AD-1 (0.800 g), and a 1% mass dilution of NMP1 in AD-3 (1.59 g), obtained in Synthesis Example 15. Stir at room temperature for 2 hours to obtain liquid crystal alignment agent (V-16).

[0294] (Example 17)

[0295] To the polyamic acid (A-9) solution (5.30 g) obtained in Synthesis Example 9, add the polyamic acid (A-16) solution (6.36 g), NMP (6.96 g), BCS (9.00 g), a 10% mass dilution of NMP in AD-1 (0.800 g), and a 1% mass dilution of NMP in AD-3 (1.59 g), obtained in Synthesis Example 16. Stir at room temperature for 2 hours to obtain liquid crystal alignment agent (V-17).

[0296] (Example 18)

[0297] To the polyamic acid (A-9) solution (5.30 g) obtained in Synthesis Example 9, a polyamic acid (A-17) solution (6.36 g), NMP (6.96 g), BCS (9.00 g), a 10% mass dilution of NMP in AD-1 (0.800 g), and a 1% mass dilution of NMP in AD-3 (1.59 g) obtained in Synthesis Example 17 were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (V-18).

[0298] (Example 19)

[0299] To the polyamic acid (A-10) solution (5.30 g) obtained in Synthesis Example 10, add the polyamic acid (A-16) solution (6.36 g), NMP (6.96 g), BCS (9.00 g), a 10% mass dilution of NMP1 in AD-1 (0.800 g), and a 1% mass dilution of NMP1 in AD-3 (1.59 g), obtained in Synthesis Example 16. Stir at room temperature for 2 hours to obtain liquid crystal alignment agent (V-19).

[0300] (Example 20)

[0301] To the polyamic acid (A-10) solution (5.30 g) obtained in Synthesis Example 10, add the polyamic acid (A-17) solution (6.36 g), NMP (6.96 g), BCS (9.00 g), a 10% mass dilution of NMP1 in AD-1 (0.800 g), and a 1% mass dilution of NMP1 in AD-3 (1.59 g), obtained in Synthesis Example 17. Stir at room temperature for 2 hours to obtain liquid crystal alignment agent (V-20).

[0302] (Comparative Example 1)

[0303] NMP (9.33 g) and BCS (4.00 g) were added to the polyamic acid (RA-1) solution (6.67 g) obtained in Synthesis Example 18, and the mixture was stirred at room temperature for 2 hours to obtain liquid crystal alignment agent (RV-1).

[0304] (Comparative Example 2)

[0305] NMP (9.33 g), BCS (4.00 g), and AD-2 (0.112 g) were added to the polyamic acid (RA-1) solution (6.67 g) obtained in Synthesis Example 18, and the mixture was stirred at room temperature for 2 hours to obtain liquid crystal alignment agent (RV-2).

[0306] [Table 2]

[0307]

[0308] Using the liquid crystal alignment agent obtained above, an FFS-driven liquid crystal cell was fabricated in the following order, and various evaluations were performed.

[0309] <Composition of FFS-driven liquid crystal cells>

[0310] A liquid crystal cell with an FFS mode liquid crystal display element was manufactured.

[0311] First, a substrate with electrodes was prepared. The substrate was a rectangular glass substrate measuring 30mm × 50mm with a thickness of 0.7mm. On the substrate, as the first layer, an ITO electrode with a full-surface pattern constituting the counter electrode was formed. On the counter electrode of the first layer, as the second layer, a SiN (silicon nitride) film formed by CVD (chemical vapor deposition) was formed. The SiN film of the second layer had a thickness of 300nm and functioned as an interlayer insulating film. On the SiN film of the second layer, as the third layer, a comb-shaped pixel electrode formed by patterning the ITO film was disposed, forming two types of pixels: a first pixel and a second pixel. Each pixel had a length of 10mm and a width of 5mm. At this point, the counter electrode of the first layer and the pixel electrode of the third layer were electrically insulated by the SiN film of the second layer.

[0312] The pixel electrode of the third layer has a comb-like shape formed by multiple 3μm wide electrode elements with an interior angle of 160° and a spacing of 6μm, arranged in parallel. A pixel has a first region and a second region, with the line connecting the bent portions of the multiple electrode elements as the boundary.

[0313] Next, the liquid crystal alignment agent obtained above was filtered through a 1.0 μm pore size filter and then coated onto the prepared electrode substrate (first glass substrate) and a glass substrate with columnar spacers having a height of 4 μm and an ITO film on the back side (second glass substrate) using spin coating. After drying on a heating plate at 80°C for 2 minutes, it was fired in a hot air circulating oven at 230°C for 30 minutes to form a coating film with a thickness of 100 nm. The coating surface was irradiated with linearly polarized ultraviolet light of wavelength 254 nm with an extinction ratio of 26:1 using a polarizer, as shown in the respective tables, to perform alignment treatment, thereby obtaining a substrate with a liquid crystal alignment film. It should be noted that the liquid crystal alignment film formed on the electrode substrate was aligned in a manner where the direction in which the inner angles of the pixel bending portion are equally divided is orthogonal to the alignment direction of the liquid crystal, and the liquid crystal alignment film formed on the second glass substrate was aligned in a manner where the alignment direction of the liquid crystal on the first glass substrate during the fabrication of the liquid crystal cell is consistent with the alignment direction of the liquid crystal on the second glass substrate. The two substrates were grouped together, and a sealant (Mitsui Chemicals XN-1500T) was printed on one substrate. The other substrate was then bonded together with the liquid crystal alignment film surfaces aligned at 0°. The sealant was then cured to create an empty cell. Liquid crystal MLC-3019 (Merck) was injected into this empty cell using a reduced-pressure 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 and left to stand overnight for evaluation.

[0314] <Evaluation of in-plane uniformity of contrast>

[0315] The deviation of the torsion angle of the liquid crystal cell was evaluated using AxoStep manufactured by AXOMETRICS. The liquid crystal cell fabricated above was placed on a measuring stage, and the distribution of circular retardation within the pixel plane was measured without applying voltage. Three times the standard deviation σ, i.e., 3σ, was calculated. It can be said that the smaller the value of 3σ, the better the in-plane uniformity. As an evaluation criterion, a 3σ value less than 1.00 was defined as "excellent," a 3σ value greater than 1.00 and less than 1.15 was defined as "good," and a 3σ value greater than 1.15 was defined as "poor."

[0316] The evaluation results of the liquid crystal display elements using the liquid crystal alignment agents of the above embodiments and comparative examples are shown in Table 3.

[0317] <Evaluation of the stability of liquid crystal alignment>

[0318] For the FFS-driven liquid crystal cell fabricated above, an AC voltage of ±5V at a frequency of 60Hz was applied for 120 hours in a constant temperature environment of 60°C. Afterwards, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited, and this state was maintained at room temperature for one day. For the liquid crystal cell subjected to the above treatment, the offset between the orientation directions of the liquid crystal in the first region and the second region of the pixel in the un-voltage-applied state was calculated in the form of angles. Specifically, the liquid crystal cell was placed between two polarizers arranged orthogonally to the polarization axes, the backlight was turned on, and the arrangement angle of the liquid crystal cell was adjusted to minimize the transmitted light intensity in the first region of the pixel. Then, the rotation angle required to minimize the transmitted light intensity in the second region of the pixel was determined. It can be said that the smaller the value of this rotation angle, the better the stability of the liquid crystal orientation. As an evaluation criterion, a value below 0.10 was defined as "excellent," a value greater than 0.10 but less than 0.30 was defined as "good," and a value greater than 0.30 was defined as "poor."

[0319] The evaluation results of the liquid crystal display elements using the liquid crystal alignment agents of the above embodiments and comparative examples are shown in Table 3.

[0320] [Table 3]

[0321]

[0322] As can be seen from Table 3 above, the liquid crystal alignment film obtained by using a liquid crystal alignment agent with specific diamines WA-1 to WA-4 exhibits at least one of the following characteristics over a wide range of light irradiation amounts: high in-plane uniformity and high stability of liquid crystal alignment, compared with the liquid crystal alignment film obtained by using a liquid crystal alignment agent composed of a diamine component without specific diamines.

[0323] Industrial availability

[0324] By using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film that suppresses image retention caused by long-term AC driving can be obtained in liquid crystal display elements using IPS driving and FFS driving methods. Therefore, its application in liquid crystal display elements requiring high display quality is expected. Moreover, these elements are also useful in liquid crystal displays for display purposes, dimming windows for controlling light transmission and cutoff, and light shutters.

[0325] It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2021-022830, filed on February 16, 2021, are incorporated herein as a disclosure of the specification of this invention.

[0326] Explanation of reference numerals in the attached figures

[0327] 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 alignment agent characterized by comprising at least one polymer A selected from the group consisting of a polyimide precursor represented by a repeating unit al represented by the following formula (1) and a repeating unit a3 represented by the following formula (3) and a polyimide which is an imidized product of the polyimide precursor, in the formula (1), R1 to R4 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms which contains a fluorine atom, or a phenyl group, at least one of R1 to R4 represents a group other than the hydrogen atom defined above, R and Z each independently represent a hydrogen atom or a monovalent organic group, and Y1 represents a divalent organic group represented by the following formula (H), in the formula (3), X3 represents a tetravalent organic group, Y3 represents a divalent organic group represented by the following formula (Y3-1), and R and Z have the same meanings as in the formula (1), In formula (H), R a represents a hydroxyl group, a halogen atom, or a monovalent organic group having 1 to 3 carbon atoms, a is an integer of 1 to 4, and, in the case where a plurality of R a are present, optionally each is the same or different, and * represents a bond. in the formula (Y3-1), Boc represents a tert-butyloxy carbonyl group.

2. The liquid crystal alignment agent according to claim 1, wherein the monovalent organic group in the formula (H) is an alkyl group, a haloalkyl group in which at least a part of hydrogen atoms in the alkyl group is substituted with a halogen atom, an alkoxy group, a haloalkoxy group in which at least a part of hydrogen atoms in the alkoxy group is substituted with a halogen atom, or an alkenyl group.

3. The liquid crystal alignment agent according to claim 1 or 2, wherein the divalent organic group represented by the formula (H) is a divalent organic group represented by any one of the following formulas (h-1) to (h-16), in the formulas (h-1) to (h-16), * represents a bonding bond.

4. The liquid crystal alignment agent according to claim 1 or 2, wherein the polymer A is at least one polymer selected from the group consisting of a polyimide precursor further having a repeating unit a2 represented by the following formula (2) and a polyimide which is an imidized product of the polyimide precursor, in the formula (2), R1 to R4, R, and Z have the same meanings as in the formula (1), and Y2 represents a divalent organic group represented by the following formula (0), *-Ar-Q2-Ar-* (0) 5. The liquid crystal alignment agent according to claim 4, wherein the divalent organic group represented by the formula (0) is a divalent organic group represented by any one of the following formulas (o-1) to (o-14), in the formulas (o-1) to (o-14), * represents a bonding bond, and in the formula (o-14), two m's are each independent.

6. The liquid crystal alignment agent according to claim 4, wherein the polymer A is at least one polymer selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product of the polyimide precursor, the polyimide precursor further having a repeating unit a2' represented by the following formula (2'), in the formula (2'), X2' represents a tetravalent organic group, Y2' represents a divalent organic group represented by the following formula (02), and R and Z have the same meanings as in the formula (1), In formula (O), each Ar independently represents a benzene ring, a biphenyl structure, or a naphthalene ring, any hydrogen atom on the ring of said Ar is optionally substituted with a halogen atom or a monovalent organic group, Q2 represents a group made of a part of said -(CH2) n - or substituted with any one of -0-, -C(=0)-, and -0-C(=0)-, wherein n is 2 to 18, and * represents a bonding bond. n - or substituted with any one of -0-, -C(=0)-, and -0-C(=0)-, wherein n is 2 to 18, and * represents a bonding bond. ​ ​ ​ ​ ​ ​ In formula (O2), m is an integer of 0 to 2, Ar2' represents an unsubstituted or substituted benzene ring, wherein, in the case where m is 0, Ar2' represents an unsubstituted benzene ring, and in the case where m is 1 or 2, each of Ar2' independently represents any one of an unsubstituted benzene ring or a benzene ring in which any hydrogen atom of the benzene ring is substituted with a halogen atom or a monovalent organic group, Q2' represents a single bond or -O-, and * represents a bonding bond, and in the case where a plurality of Ar2' and Q2' are present, each of them is optionally the same or different.

7. The liquid crystal aligning agent according to claim 6, wherein the divalent organic group represented by formula (O2) is a divalent organic group represented by any one of the following formulas (o2-1) to (o2-12), in formulas (o2-1) to (o2-12), * represents a bonding bond.

8. The liquid crystal aligning agent according to claim 1 or 2, wherein the polymer A contains the sum of the repeating unit al and the imidized structural unit of the repeating unit al in 10 to 95 mol% of the total repeating units.

9. The liquid crystal aligning agent according to claim 4, wherein the polymer A contains the sum of the repeating unit a2 and the imidized structural unit of the repeating unit a2 in 10 to 90 mol% of the total repeating units.

10. The liquid crystal aligning agent according to claim 6, wherein the polymer A contains the sum of the repeating unit al, the repeating unit a2, the repeating unit a2', and the imidized structural units thereof in 30 mol% or more of the total repeating units.

11. The liquid crystal aligning agent according to claim 1 or 2, wherein the liquid crystal aligning agent is used for a liquid crystal aligning film for a photo-alignment process.

12. A liquid crystal aligning film obtained from the liquid crystal aligning agent according to any one of claims 1 to 11.

13. A liquid crystal display element provided with the liquid crystal aligning film according to claim 12.

14. A production method of a liquid crystal aligning film for 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 11 to a substrate; Step 2: a step of performing baking on the applied liquid crystal aligning agent; and Step 3: a step of performing an alignment treatment on the film obtained in Step 2 as necessary.

15. The production method of a liquid crystal aligning film according to claim 14, wherein the alignment treatment is a photo-alignment treatment.

16. The production method of a liquid crystal aligning film according to claim 15, wherein The irradiation amount of the radiation in the photo-alignment treatment is 100 mJ / cm 2 ~ 1500 mJ / cm 2 .

17. The production method of a liquid crystal aligning film according to any one of claims 14 to 16, wherein further comprising Step 4: a step of performing a heat treatment at 50°C to 300°C on the film subjected to the alignment treatment in Step 3.

18. The production method of a liquid crystal aligning film according to any one of claims 14 to 16, wherein the liquid crystal display element is a liquid crystal display element of an IPS drive system or an FFS drive system.

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