Liquid crystal alignment agent for photo-alignment method, liquid crystal photo-alignment film and liquid crystal display element

Abstract

The invention relates to a liquid crystal alignment agent for a photoalignment method, a liquid crystal photoalignment film and a liquid crystal display element. The invention relates to a liquid crystal alignment agent for a light alignment method, a liquid crystal light alignment film formed by the liquid crystal alignment agent for the light alignment method, and a liquid crystal display element comprising the liquid crystal light alignment film. The liquid crystal alignment agent for the photo-alignment method comprises a polymer component (A) and a solvent (B). The polymer component (A) comprises a first polymer (A1). The first polymer (A1) is selected from at least one of a group consisting of a polyimide precursor and an imidized polymer formed by the polyimide precursor, and the polyimide precursor of the first polymer (A1) comprises a structure represented by formula (I). Y1 in the formula (I) represents a divalent organic group with a structure shown in a formula (II), and X1, X2, X3, Ar, M1, M2 and * are defined as the description and claims respectively.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element, and particularly relates to a liquid crystal alignment agent for a photo-alignment method that is fast in charge relaxation, a liquid crystal photo-alignment film formed from the liquid crystal alignment agent for the photo-alignment method, and a liquid crystal display element including the liquid crystal photo-alignment film. BACKGROUND

[0002] Generally, a liquid crystal display element includes a liquid crystal layer interposed between two glass substrates, and a liquid crystal alignment film for controlling the alignment of liquid crystal molecules in the liquid crystal layer. In terms of the driving mode of the liquid crystal molecules, there are currently liquid crystal display elements driven in a vertical electric field and liquid crystal display elements driven in a horizontal electric field. The liquid crystal display elements driven in a vertical electric field are, for example, twisted nematic (TN) type liquid crystal display elements and vertical alignment (VA) type liquid crystal display elements. The liquid crystal display elements driven in a horizontal electric field are, for example, in-plane switching (IPS) type liquid crystal display elements and fringe field switching (FFS) type liquid crystal display elements.

[0003] The most popular liquid crystal alignment film in the industry at present is obtained by rubbing the surface of a film-like object composed of a polyamide acid and / or a polyimide obtained by imidization of the polyamide acid in one direction, thereby forming grooves on the surface of the film-like object that enable liquid crystal molecules to align in a certain direction. Rubbing is a simple, high-yield, and commonly used alignment treatment method in the industry. However, as the performance requirements for liquid crystal display elements increase, the image quality becomes finer, and the size becomes larger, the damage to the liquid crystal alignment film caused by rubbing leads to various problems such as non-uniformity of the alignment of the liquid crystal alignment film. Therefore, a photo-alignment method in which a liquid crystal alignment film is given the ability to align by irradiation with polarized radiation has been proposed as an alternative to rubbing, for example, the photo-alignment method disclosed in Japanese Patent Laid-Open No. H09-297313.

[0004] However, the liquid crystal alignment film obtained by the photo-alignment method can avoid the problems caused by the rubbing alignment treatment method, but the liquid crystal display element including the liquid crystal alignment film obtained by the photo-alignment method still has the problem of slow charge relaxation, and cannot meet the application requirements. SUMMARY

[0005] A first object of the present application is to provide a liquid crystal alignment agent for a photo-alignment method.

[0006] The liquid crystal alignment agent for the photo-alignment method of the present application comprises a polymer component (A) and a solvent (B).

[0007] The polymer component (A) comprises a first polymer (A1), and the first polymer (A1) is at least one selected from the group consisting of a polyimide precursor and an imidized polymer formed from the polyimide precursor.

[0008] The polyimide precursor of the first polymer (A1) comprises a structure represented by Formula (I),

[0009]

[0010] X 1 represents at least one selected from the group consisting of structures represented by Formula (I-1) to Formula (I-7), and "*" represents a bonding position,

[0011]

[0012] X 11 , X 12 , X 13 , and X 14 each independently represents hydrogen, halogen, an alkyl group having a carbon number of 1 to 6, an alkenyl group having a carbon number of 2 to 6, an alkynyl group having a carbon number of 2 to 6, a monovalent organic group having a carbon number of 1 to 6 and containing fluorine, or a phenyl group,

[0013] X 15 and X 16 each independently represents hydrogen or a methyl group,

[0014] X 2 represents hydrogen or an alkyl group having a carbon number of 1 to 4,

[0015] X 3 represents hydrogen or an alkyl group having a carbon number of 1 to 4,

[0016] Y 1 represents a divalent organic group of a structure represented by Formula (II),

[0017]

[0018] "*" represents a bonding position,

[0019] Ar represents a divalent aromatic group of any one of a phenyl group, a biphenyl group, or a naphthyl group, and any hydrogen atom of the phenyl group, the biphenyl group, or the naphthyl group can be substituted with a monovalent group, M 1 and M 2 each independently represents an alkyl group having a carbon number of 1 to 4.

[0020] In the liquid crystal alignment agent for the photo-alignment method of the present application, X 1the structure represented by formula (I-1) is selected from structures represented by formulae (I-1-1) to (I-1-6),

[0021]

[0022] In the liquid crystal alignment agent for the photo-alignment method according to the present application, X 1 the structure represented by formula (I-1) is selected from structures represented by formulae (I-1-1) to (I-1-6),

[0023]

[0024] In the liquid crystal alignment agent for the photo-alignment method according to the present application, M 1 and M 2 each independently represents an alkyl group having a carbon number of 1 to 2.

[0025] In the liquid crystal alignment agent for the photo-alignment method according to the present application, the polymer component (A) further includes a second polymer (A2), and the second polymer (A2) is selected from at least one of the group consisting of a polyimide precursor and an imidized polymer formed from the polyimide precursor, and the polyimide precursor of the second polymer (A2) does not include the structure represented by formula (I) in the first polymer (A1).

[0026] In the liquid crystal alignment agent for the photo-alignment method according to the present application, the polyimide precursor of the second polymer (A2) is formed by reaction of a reaction composition including a tetracarboxylic dianhydride component (a2) and a diamine component (b2), and the tetracarboxylic dianhydride component (a2) includes a tetracarboxylic dianhydride compound having a structure represented by formula (III),

[0027]

[0028] Z 11 represents a single bond, and "*" represents a bonding position.

[0029] In the liquid crystal alignment agent for the photo-alignment method according to the present application, the diamine component (b2) includes a diamine compound having a nitrogen atom-containing structure, and the nitrogen atom structure in the diamine compound having a nitrogen atom-containing structure is selected from at least one of the group consisting of a nitrogen atom-containing heterocycle, a secondary amino group, and a tertiary amino group.

[0030] A second object of the present application is to provide a liquid crystal photo-alignment film.

[0031] The liquid crystal photo-alignment film according to the present application is formed from the liquid crystal alignment agent for the photo-alignment method as described above.

[0032] A third object of the present application is to provide a liquid crystal display element.

[0033] The liquid crystal display element of the present application comprises the liquid crystal photo-alignment film as described above.

[0034] The present application has the advantage that the liquid crystal photo-alignment film formed by the liquid crystal alignment agent for the photo-alignment method can impart the liquid crystal display element with the characteristic of fast charge relaxation by using the first polymer (A1) prepared from the polyimide precursor comprising the structure represented by Formula (II). DETAILED DESCRIPTION

[0035] The present application provides a liquid crystal alignment agent for the photo-alignment method, and comprises a polymer component (A) and a solvent (B). The polymer component (A) comprises a first polymer (A1).

[0036] Polymer component (A)

[0037] First polymer (A1)

[0038] The first polymer (A1) is selected from at least one of a polyimide precursor and an imidized polymer formed from the polyimide precursor. The polyimide precursor of the first polymer (A1) comprises a structure represented by Formula (I).

[0039]

[0040] In the Formula (I), X 1 represents at least one of a structure represented by Formula (I-1) to Formula (I-7), X 2 represents hydrogen or an alkyl group having a carbon number of 1 to 4, X 3 represents hydrogen or an alkyl group having a carbon number of 1 to 4.

[0041]

[0042] In the Formula (I-1) to Formula (I-7), “*” represents a bonding position. In the Formula (I-1), X 11 , X 12 , X 13 , and X 14 each independently represents hydrogen, halogen, an alkyl group having a carbon number of 1 to 6, an alkenyl group having a carbon number of 2 to 6, an alkynyl group having a carbon number of 2 to 6, a monovalent organic group having a carbon number of 1 to 6 and containing fluorine, or a phenyl group. In the Formula (I-7), X 15 and X 16 each independently represents hydrogen or a methyl group.

[0043] In some embodiments of the present application, the structure represented by Formula (I-1) of X 1 is selected from structures represented by Formula (I-1-1) to (I-1-6).

[0044]

[0045] In some embodiments of the present application, the X 1 is selected from the group consisting of structures represented by formula (I-1-1).

[0046]

[0047] In the formula (I), Y 1 represents a divalent organic group represented by formula (II).

[0048]

[0049] In the formula (II), "*" represents a bonding position, Ar represents a divalent aromatic group of any one of phenyl, biphenyl, or naphthyl, and any hydrogen atom of the phenyl, the biphenyl, or the naphthyl can be substituted with a monovalent group, M 1 and M 2 each independently represent an alkyl group having a carbon number of 1 to 4.

[0050] In some embodiments of the present application, the M 1 and the M 2 each independently represent an alkyl group having a carbon number of 1 to 2.

[0051] In some embodiments of the present application, the first polymer (A1) is selected from at least one of a polyimide precursor obtained by reacting a tetracarboxylic dianhydride component (a1) and a diamine component (b1), and an imidized polymer formed from the polyimide precursor.

[0052] 〔Tetracarboxylic dianhydride component (a1)〕

[0053] (Alicyclic tetracarboxylic dianhydride compound (a1-1))

[0054] In some embodiments of the present application, the tetracarboxylic dianhydride component (a1) comprises an alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11) or a derivative thereof.

[0055]

[0056] The alicyclic tetracarboxylic dianhydride (a1-1) represented by the formula (A11) or a derivative thereof can be composed of a single tetracarboxylic dianhydride or a derivative thereof, or can be composed of a plurality of tetracarboxylic dianhydrides or derivatives thereof. The alicyclic tetracarboxylic dianhydride (a1-1) represented by the formula (A11) is, for example, an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an alicyclic structure. However, none of the four carboxyl groups is bonded to an aromatic ring. Alternatively, a part thereof can have a chain hydrocarbon structure or an aromatic ring structure, without being composed only of an alicyclic structure. The aromatic tetracarboxylic dianhydride is, for example, an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an aromatic ring. However, the aromatic tetracarboxylic dianhydride can have a chain hydrocarbon structure or an alicyclic structure, without being composed only of an aromatic ring structure. The acyclic aliphatic tetracarboxylic dianhydride can be, for example, an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. However, the acyclic aliphatic tetracarboxylic dianhydride can have an alicyclic structure or an aromatic ring structure, without being composed only of a chain hydrocarbon structure.

[0057] In the formula (A11), X 1 is selected from at least one of the structures represented by the formulae (I-1) to (I-7), and "*" represents a bonding position.

[0058]

[0059]

[0060] In the formula (I-1), X 11 , X 12 , X 13 , and X 14 each independently represent hydrogen, a halogen, an alkyl group having a carbon number of 1 to 6, an alkenyl group having a carbon number of 2 to 6, an alkynyl group having a carbon number of 2 to 6, a monovalent organic group having a carbon number of 1 to 6 and containing a fluorine atom, or a phenyl group. In the formula (I-7), X 15 , and X 16 each independently represent hydrogen or a methyl group.

[0061] In some embodiments of the present application, in the formula (A11), the X 1 represented by the formula (I-1) is selected from the structures represented by the formulae (I-1-1) to (I-1-6).

[0062]

[0063] In some embodiments of the present application, preferably, the X 1 represented by the formula (I-1) is the structure represented by the formula (I-1-1).

[0064] In some embodiments of the present application, based on the total amount of 100 moles of the tetracarboxylic dianhydride component (a1), the cycloaliphatic tetracarboxylic dianhydride of formula (A11) (a1-1) is used in an amount of 30 to 100 moles, preferably in an amount of 40 to 100 moles, and more preferably in an amount of 50 to 100 moles.

[0065] (other tetracarboxylic dianhydride compounds (a1-2))

[0066] In some embodiments of the present application, the tetracarboxylic dianhydride component (a1) further comprises other tetracarboxylic dianhydride compounds (a1-2).

[0067] In some embodiments of the present application, the other tetracarboxylic dianhydride compounds (a1-2) comprise tetracarboxylic dianhydride compounds of formula (A12) or derivatives thereof.

[0068]

[0069] In the formula (A12), X 1' represents a structure of formula (A12-1) to formula (A12-32), and "*" represents a bonding position.

[0070]

[0071]

[0072]

[0073]

[0074] In the formula (A12-1), a1 is 1 to 12. In the formula (A12-5), X 11' represents a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or amido, and a1 represents 0 or 1. In the formula (A12-6), X 11' and X 12' each independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or amido, and a plurality of X 12' are the same or different, and a1 represents 0 or 1. In the formula (A12-11), a1 represents 2 to 6. In the formula (A12-13), a1 represents 1 to 2. In the formula (A12-14), X 13'respectively independently represent hydrogen, halogen, an alkyl group having a carbon number of 1 to 6, an alkenyl group having a carbon number of 2 to 6, an alkynyl group having a carbon number of 2 to 6, a monovalent organic group containing fluorine and having a carbon number of 1 to 6, or a phenyl group, and a plurality of X 13' are the same or different. From the viewpoint of liquid crystal alignment properties, preferably, the X 13' respectively independently represent hydrogen, halogen, methyl, or ethyl, more preferably, the X 13' respectively independently represent hydrogen or methyl.

[0075] In some embodiments of the present application, the formula (A12-5) and the formula (A12-6) include, but are not limited to

[0076]

[0077] The other tetracarboxylic dianhydride compound (a1-2) can be used alone or in a mixture of a plurality of kinds. In some embodiments of the present application, based on the total amount of the tetracarboxylic dianhydride component (a1) being 100 moles, the amount of use of the other tetracarboxylic dianhydride compound (a1-2) is 0 to 70 moles, preferably, the amount of use of the other tetracarboxylic dianhydride compound (a1-2) is 0 to 60 moles, more preferably, the amount of use of the other tetracarboxylic dianhydride compound (a1-2) is 0 to 50 moles.

[0078] 〔Diamine component (b1)〕

[0079] (diamine compound (b1-1))

[0080] In some embodiments of the present application, the diamine component (b1) includes a diamine compound (b1-1) having a structure represented by formula (A21).

[0081]

[0082] In the formula (A21), Ar represents a divalent aromatic group of any one of a phenyl group, a biphenyl group, or a naphthyl group, and any hydrogen atom on the phenyl group, the biphenyl group, or the naphthyl group can be substituted with a monovalent group, M 1 and M 2 respectively independently represent an alkyl group having a carbon number of 1 to 4.

[0083] In some embodiments of the present application, the diamine compound (b1-1) is a compound selected from the group consisting of structures represented by formula (A21-1) to formula (A21-2).

[0084]

[0085] In the formula (A21-1) to the formula (A21-2), Ar represents a divalent aromatic group of any one of a phenyl group, a biphenyl group, or a naphthyl group, and any hydrogen atom of the phenyl group, the biphenyl group, or the naphthyl group can be substituted with a monovalent group, M 1 and M 2 each independently represents an alkyl group having a carbon number of 1 to 4.

[0086] In some embodiments of the present application, the compound of the structure represented by the formula (A21-1) to the formula (A21-2) is, for example, but not limited to, a diamine compound represented by the formula (b1-1-1) to the formula (b1-1-8).

[0087]

[0088]

[0089] In some embodiments of the present application, based on the total use amount of the diamine component (b2) being 100 moles, the use amount of the diamine compound (b2-1) is 10 moles to 70 moles, preferably, the use amount of the diamine compound (b2-1) is 15 moles to 60 moles, more preferably, the use amount of the diamine compound (b2-1) is 20 moles to 50 moles.

[0090] When the diamine component (b2) does not contain the diamine compound (b2-1), the liquid crystal display element including the liquid crystal photo-alignment film formed using the liquid crystal alignment agent for the photo-alignment method is slow in charge relaxation.

[0091] (diamine compound (b1-2))

[0092] In some embodiments of the present application, the diamine component (b1) further contains a diamine compound (b1-2). The diamine compound (b1-2) is a diamine compound represented by the formula (A22-1) to the formula (A22-2).

[0093]

[0094]

[0095] In the formula (A22-1), Y 21 represents a divalent organic group represented by the formula (A22-3), and a plurality of Y 22 each independently represents hydrogen or an alkyl group having a carbon number of 1 to 6. In the formula (A22-2), a plurality of Y 23 each independently represents a divalent organic group represented by the formula (A22-3').

[0096]

[0097] In the divalent organic groups shown in formula (A22-3), Ar independently represents a divalent benzene ring, biphenyl structure, or naphthalene ring, and the hydrogen atoms of the benzene ring, biphenyl structure, or naphthalene ring may be substituted by monovalent substituents or may not be substituted; Y 21' Representative - (CH2) n -, where n represents an integer from 2 to 18, and -(CH2) n At least one of the -CH2- in - can be replaced by -O-, -C(=O)- or -OC(=O)- or not replaced; p1 represents 0 or 1; "*" represents the bond position.

[0098] In the divalent organic groups represented by formula (A22-3'), Ar' independently represents a divalent benzene ring or biphenyl structure, and the hydrogen atoms of the benzene ring or biphenyl structure may be substituted by monovalent substituents or remain unsubstituted; Y 23' Representative - (CH2) n -, where n represents an integer from 2 to 18, and -(CH2) n At least one of the -CH2- in - can be replaced by -O-, -C(=O)- or -OC(=O)- or not replaced; p2 represents 0 or 1; "*" represents the bond position.

[0099] In the divalent organic groups shown in formula (A22-3) and the divalent organic groups shown in formula (A22-3'), the monovalent substituents of the benzene ring, biphenyl structure, or naphthyl ring are, for example, halogens, alkyl groups having 1 to 10 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, alkoxy groups having 1 to 10 carbon atoms, fluoroalkyl groups having 1 to 10 carbon atoms, fluoroalkenyl groups having 2 to 10 carbon atoms, fluoroalkoxy groups having 1 to 10 carbon atoms, carboxyl groups, hydroxyl groups, alkoxycarbonyl groups having 1 to 10 carbon atoms, cyano groups, or nitro groups, etc.

[0100] In some embodiments of the present invention, from the viewpoint of improving liquid crystal alignment, it is preferred that the divalent organic group represented by formula (A22-3) is a group represented by formula (A22-3-1) to formula (A22-3-16), where "*" represents a bond position.

[0101]

[0102]

[0103] In the formula (A22-3-1), m is 0 to 1, and n is 1 to 6. In the formula (A22-3-2), n is 1 to 6. In the formula (A22-3-3), n is 2 to 6. In the formula (A22-3-4), n is 1 to 6. In the formula (A22-3-5), n is 1 to 6. In the formula (A22-3-6), n is 2 to 6. In the formula (A22-3-7), n is 1 to 6. In the formula (A22-3-8), n is 1 to 6. In the formula (A22-3-9), n is 2 to 6. In the formula (A22-3-10), m is 1 to 3, and n is 1 to 4. In the formula (A22-3-11), n is 1 to 6. In the formula (A22-3-12), n is 1 to 6. In the formula (A22-3-13), m is 0 to 1, and n is 1 to 6. In the formula (A22-3-14), m is 1 to 3, and n is 1 to 4.

[0104] In some embodiments of the present application, the bivalent organic group represented by the formula (A22-3') is preferably a group represented by the formula (A22-3-7) to the formula (A22-3-16) from the viewpoint of improving the liquid crystal alignment property.

[0105] When the diamine compound (b 1-2) contains a plurality of diamine compounds represented by the formula (A22-1), Y 21 represents a combination of the diamine compounds represented by the formula (A22-3-15) to the formula (A22-3-16). 21 represents a combination of the diamine compounds represented by the formula (A22-3-15) to the formula (A22-3-16).

[0106] In some embodiments of the present application, the diamine compound represented by the formula (A22-2) is, for example, but not limited to, a diamine compound represented by the formula (A22-2-1) to the formula (A22-2-5).

[0107]

[0108] In the formula (A22-2-1), m is 1 to 6, and n is 1 to 6. In the formula (A22-2-2), m is 1 to 6, and n is 1 to 6. In the formula (A22-2-3), m is 2 to 6, and n is 2 to 6.

[0109] The diamine compound (b 1-2) can be used alone or in a mixture of a plurality of kinds. In some embodiments of the present application, the diamine compound (b 1-2) is used in an amount of 20 to 90 moles, preferably 25 to 80 moles, and more preferably 30 to 70 moles, based on 100 moles of the total amount of the diamine component (b 1).

[0110] (diamine compound (b 1-3))

[0111] In some embodiments of the present application, the diamine component (b 1) further includes a diamine compound (b 1-3) having a group of -N(D)-.

[0112] From the viewpoint of improving the voltage holding ratio of the liquid crystal display element, the molecular structure of the first polymer (A1) can optionally have a group of -N(D)- (D represents a urethane-based protective group). The first polymer (A1) having a group of -N(D)- can be obtained by a method in which a monomer having a group of -N(D)- is used as at least a part of the reaction raw material, or by a method in which a monomer having a group of -N(D)- is used as the following end-capping agent. In some specific examples of the present application, the monomer having a group of -N(D)- is, for example, a diamine compound (b 1-3) having a group of -N(D)-. For example, the urethane-based protective group is, for example, but not limited to, a tert-butoxycarbonyl group (abbreviated as Boc) or a 9-fluorenylmethoxycarbonyl group, and the like.

[0113] In some embodiments of the present application, preferably, the diamine compound (b 1-3) having a group of -N(D)- includes a diamine compound having at least one aromatic group (for example, a benzene ring). More preferably, the diamine compound (b 1-3) having a group of -N(D)- includes a diamine compound having at least one aromatic group and having a residue other than the substituent (D) as a carbon number of 6 to 30. In some specific examples of the present application, the diamine compound (b 1-3) having a group of -N(D)- is, for example, but not limited to, a diamine compound represented by formula (A23-1) to formula (A23-11).

[0114]

[0115]

[0116]

[0117] In the formula (A23-1), n is 1 to 6. In the formula (A23-2), n is 1 to 6. In the formula (A23-4), m is 1 to 6, and n is 1 to 6. In the formula (A23-7), m is 1 to 6, and n is 1 to 6. In the formula (A23-9), n is 1 to 6. In the formula (A23-11), n is 1 to 6.

[0118] The diamine compound (b1-3) having a group of -N(D)- can be used alone or in a mixture of a plurality of kinds. In some embodiments of the present application, the diamine compound (b1-3) having a group of -N(D)- is used in an amount of 2 to 60 moles, preferably 10 to 50 moles, more preferably 15 to 40 moles, based on 100 moles of the total amount of the diamine component (b1).

[0119] (diamine compound (b1-4))

[0120] In some embodiments of the present application, the diamine component (b1) further contains another diamine compound (b1-4).

[0121] The other diamine compound (b1-4) is, for example, but not limited to, a diamine compound having a photoaligning group, 4-amino-N-methylphenethylamine, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, a diamine compound having a carboxyl group, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ketone, 1,4-bis(4-aminobenzyl)benzene, 4,4'-diaminodiphenyl ether, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-inden-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-6-amine, a diamine compound having a urea bond, a diamine compound having an amide bond, a diamine compound having a terminal photopolymerizable group, a diamine compound having a siloxane bond, or a diamine compound having an oxazoline structure, and the like.

[0122] The diamine compound having a photoaligning group is, for example, but not limited to, 4,4'-diaminoazobenzene, or a diamine compound represented by the formula (A24-1) to formula (A24-3), and the like.

[0123]

[0124]

[0125] The diamine compound having a carboxyl group is, for example, but not limited to, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, or a diamine compound represented by formula (A24-4) to formula (A24-7), and the like.

[0126]

[0127] In the formula (A24-4), Y 41 represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)-, or -N(CH3)CO-; m1 and m2 each independently represent an integer of 0 to 4, and (m1+m2) represents an integer of 1 to 4. In the formula (A24-5), m3 and m4 each independently represent an integer of 1 to 5. In the formula (A24-6), Y 42 represents a linear or branched alkyl group having a carbon number of 1 to 5; and m5 represents an integer of 1 to 5. In the formula (A24-7), Y 43 and Y 44 each 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-; and m6 represents an integer of 1 to 4.

[0128] The diamine compound having a urea bond is, for example, but not limited to, a diamine compound represented by formula (A24-8) to formula (A24-10), and the like.

[0129]

[0130] In the formula (A24-8), n1 is 0 to 6, and n2 is 1 to 6. In the formula (A24-9), n1 is 1 to 6, and n2 is 1 to 6. In formula (A24-10), n is 1 to 6.

[0131] The diamine compound having an amide bond is, for example, but not limited to, a diamine compound having an amide bond represented by formula (A24-11) to formula (A24-13).

[0132]

[0133] In the formula (A24-12), n is 1 to 6. In the formula (A24-13), n1 is 1 to 6, and n2 is 1 to 6.

[0134] The diamine compound having a photopolymerizable group at the terminal includes, for example but not limited to, 2-(2,4-diaminophenoxy)ethyl methacrylate, or 2,4-diamino-N,N-diallyl aniline, and the like.

[0135] The diamine compound having a siloxane bond includes, for example but not limited to, 3-bis(3-aminopropyl)-tetramethyldisiloxane.

[0136] The diamine compound having an oxazoline structure includes, for example but not limited to, a diamine compound represented by the formula (A24-14) to the formula (A24-15), and the like.

[0137]

[0138] The other diamine compound (b1-4) can be used alone or in a mixture of two or more. In some embodiments of the present application, the amount of the other diamine compound (b1-4) used is 0 to 65 moles, preferably 0 to 50 moles, and more preferably 0 to 35 moles, based on 100 moles of the total amount of the diamine component (b1).

[0139] 〈Second polymer (A2)〉

[0140] In some embodiments of the present application, the polymer component (A) further includes a second polymer (A2), and the second polymer (A2) is selected from at least one of a polyimide precursor and an imidized polymer formed from the polyimide precursor, and the polyimide precursor of the second polymer (A2) does not include the structure represented by the formula (I) in the first polymer (A1).

[0141] In some embodiments of the present application, the polyimide precursor of the second polymer (A2) is formed by reacting a reaction composition including a tetracarboxylic dianhydride component (a2) and a diamine component (b2), and the tetracarboxylic dianhydride component (a2) includes a tetracarboxylic dianhydride compound having a structure represented by the formula (III),

[0142]

[0143] Z 11 represents a single bond, and "*" represents a bonding position.

[0144] 〔Tetracarboxylic dianhydride component (a2)〕

[0145] The tetracarboxylic dianhydride component (a2) is, for example, but not limited to, a non-cyclic aliphatic tetracarboxylic dianhydride compound, a cycloaliphatic tetracarboxylic dianhydride compound, an aromatic tetracarboxylic dianhydride compound, or a derivative of these compounds. The non-cyclic aliphatic tetracarboxylic dianhydride compound, the cycloaliphatic tetracarboxylic dianhydride compound, and the aromatic tetracarboxylic dianhydride compound are, for example, tetracarboxylic dianhydride compounds in the first polymer (A1). Preferably, the tetracarboxylic dianhydride component (a2) comprises a cycloaliphatic tetracarboxylic dianhydride or a derivative thereof represented by formula (A11), or a tetracarboxylic dianhydride compound represented by formula (A12) as shown above and X 1' a tetracarboxylic dianhydride compound represented by formula (A12-1) to formula (A12-6) or a derivative thereof. The tetracarboxylic dianhydride component (a2) can be used alone or in a mixture of a plurality of kinds.

[0146] (tetracarboxylic dianhydride compound (a2-1))

[0147] In some embodiments of the present application, preferably, the tetracarboxylic dianhydride component (a2) comprises a tetracarboxylic dianhydride compound (a2-1) represented by formula (A12) and X 1' a tetracarboxylic dianhydride compound (a2-1) represented by formula (III).

[0148]

[0149] In the formula (III), Z 11 represents a single bond, and "*" represents a bonding position.

[0150] The tetracarboxylic dianhydride compound (a2-1) can be used alone or in a mixture of a plurality of kinds.

[0151] In some embodiments of the present application, more preferably, the tetracarboxylic dianhydride component (a2) comprises a tetracarboxylic dianhydride compound (a2-1) represented by formula (IV).

[0152]

[0153] In some embodiments of the present application, based on the total amount of the tetracarboxylic dianhydride component (a2) being 100 moles, the tetracarboxylic dianhydride compound (a2-1) is used in an amount of 30 to 100 moles, preferably, the tetracarboxylic dianhydride compound (a2-1) is used in an amount of 40 to 100 moles, more preferably, the tetracarboxylic dianhydride compound (a2-1) is used in an amount of 50 to 100 moles.

[0154] (diamine component (b2))

[0155] (tetracarboxylic dianhydride compound (a2-1))

[0156] In some embodiments of the present application, the diamine component (b2) includes a diamine compound having a nitrogen atom-containing structure (b2-1), and the nitrogen atom-containing structure in the diamine compound having a nitrogen atom-containing structure (b2-1) is selected from at least one of a nitrogen atom-containing heterocycle, a secondary amino group, and a tertiary amino group.

[0157] The nitrogen atom-containing heterocycle in the diamine compound having a nitrogen atom-containing structure (b2-1) is, for example, but not limited to, a pyrrole, an imidazole, a pyrazole, a triazole, a pyridine, a pyrimidine, a pyridazine, a pyrazine, an indole, a benzimidazole, a purine, a quinoline, an isoquinoline, a phthalazine, a triazine, a carbazole, an acridine, a piperidine, a piperazine, a pyrrolidine, or a hexamethylene imine, etc. Preferably, the nitrogen atom-containing heterocycle is a pyridine, a pyrimidine, a pyrazine, a piperidine, a piperazine, a quinoline, a carbazole, or an acridine.

[0158] In some embodiments of the present application, the nitrogen atom-containing structure in the diamine compound having a nitrogen atom-containing structure (b2-1) is a secondary amino group and a tertiary amino group represented by Formula (B21).

[0159]

[0160] In the Formula (B21), Z represents hydrogen, an alkyl group having a carbon number of 1 to 10, a cycloalkyl group, or an aryl group; and “*” represents a bonding position.

[0161] The alkyl group having a carbon number of 1 to 10 is, for example, but not limited to, a methyl group, an ethyl group, or a propyl group. The cycloalkyl group is, for example, but not limited to, a cyclohexyl group. The aryl group is, for example, but not limited to, a phenyl group or a tolyl group. Preferably, Z is hydrogen or a methyl group.

[0162] In some embodiments of the present application, the diamine compound having a nitrogen atom-containing structure (b2-1) is, for example, but not limited to, a 2,6-diaminopyridine, a 3,4-diaminopyridine, a 2,4-diaminopyrimidine, a 3,6-diaminocarbazole, an N-methyl-3,6-diaminocarbazole, a 1,4-bis-(4-aminophenyl)-piperazine, a 3,6-diaminoacridine, an N-ethyl-3,6-diaminocarbazole, an N-phenyl-3,6-diaminocarbazole, a diamine compound represented by Formula (B21-1) to Formula (B21-8), or a diamine compound represented by Formula (B21-9) to Formula (B21-26).

[0163]

[0164]

[0165]

[0166] ​In the formula (B21-5), n represents 1 to 4. In the formula (B21-6), n represents 1 to 4. The diamine compound (b2-1) having a nitrogen atom-containing structure can be used alone or in a mixture of two or more kinds.

[0167] In some embodiments of the present application, the diamine compound (b2-1) having a nitrogen atom-containing structure is used in an amount of 15 to 100 mol, preferably in an amount of 20 to 90 mol, and more preferably in an amount of 25 to 80 mol, based on 100 mol of the total amount of the diamine component (b2).

[0168] In some embodiments of the present application, the first polymer (Al) is used in an amount of 5 to 85 parts by weight, preferably in an amount of 10 to 80 parts by weight, and more preferably in an amount of 10 to 75 parts by weight, and the second polymer (A2) is used in an amount of 15 to 95 parts by weight, preferably in an amount of 20 to 90 parts by weight, and more preferably in an amount of 25 to 90 parts by weight, based on 100 parts by weight of the total amount of the polymer component (A). When both the amount of the first polymer (Al) and the amount of the second polymer (A2) fall within the above ranges, the liquid crystal display element including the liquid crystal photo-alignment film formed by the liquid crystal alignment agent for the photo-alignment method has a faster charge relaxation characteristic.

[0169] <Method for producing the first polymer (Al) and the second polymer (A2)>

[0170] The first polymer (Al) and the second polymer (A2) can be produced by subjecting the above-mentioned tetracarboxylic dianhydride component and the diamine component to a (polycondensation) reaction in a solvent. When a part of the first polymer (Al) and the second polymer (A2) has an amic acid structure, for example, a polymer having an amic acid structure (i.e., a polyamic acid) is obtained by subjecting the tetracarboxylic dianhydride component and the diamine component to a reaction. The solvent is not particularly limited as long as it can dissolve the polymer to be produced. For example, the solvent is, for example, but not limited to, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, or 1,3-dimethyl-2-imidazolidinone, and the like. In some embodiments of the present application, when the solvent solubility of the polymer is high, the solvent is, for example, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a solvent represented by Formula (D-1) to Formula (D-3).

[0171]

[0172] HOCH2-CH2-O-Z 2 HO-CH2-CH2-O-CH2-CH2-O-Z

[0173] HO-CH2-CH2-O-CH2-CH2-O-Z 3 HO-CH2-CH2-O-CH2-CH2-O-Z

[0174] HO-CH2-CH2-O-CH2-CH2-O-Z 1 HO-CH2-CH2-O-CH2-CH2-O-Z 2 HO-CH2-CH2-O-CH2-CH2-O-Z 3 HO-CH2-CH2-O-CH2-CH2-O-Z

[0175] The solvent can be used alone or in a mixture of two or more. Further, even if a solvent that cannot dissolve the polymer is used, the solvent that cannot dissolve the polymer can be used in a mixture with the above-mentioned solvent, within a range in which the produced polymer does not precipitate. When the tetracarboxylic dianhydride component and the diamine component are subjected to a reaction in a solvent, the reaction can be performed at an arbitrary concentration, and preferably, the total concentration of the tetracarboxylic dianhydride component and the diamine component is 1 wt% to 50 wt%, and more preferably, the total concentration of the tetracarboxylic dianhydride component and the diamine component is 5 wt% to 30 wt%. The reaction can also be performed at a high concentration at the start, and then, a solvent can be additionally added. When the reaction is performed, preferably, the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic dianhydride component is 0.8 to 1.2. As in general polycondensation reactions, the closer the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic dianhydride component is to 1.0, the larger the molecular weight of the produced first polymer (Al) or second polymer (A2) is.

[0176] The polymer having an amic acid ester structure can be obtained, for example, by a known method, and the known method is (1) a method of reacting the polyamic acid obtained by the above-mentioned method with an esterification agent, (2) a method of reacting a tetracarboxylic acid diester compound with a diamine compound, or (3) a method of reacting a tetracarboxylic acid diester dihalide with a diamine compound.

[0177] The imidized polymer in the first polymer (Al) or the second polymer (A2) of the liquid crystal alignment agent for the photo-alignment method of the present application can be obtained, for example, by ring-closing the polymer having an amic acid ester structure. In the imidized polymer, the ring-closing rate (also referred to as the imidization rate) of the functional group of the amic acid group or a derivative thereof does not necessarily have to be 100%, and the imidization rate of the imidized polymer can be arbitrarily adjusted depending on the use and / or purpose.

[0178] As the method for obtaining the imidized polymer, for example, there are thermal imidization of directly heating a solution containing a polymer having an amic acid ester structure, or catalyst imidization of adding a catalyst to the solution containing a polymer having an amic acid ester structure. In the case of thermal imidization in the solution containing a polymer having an amic acid ester structure, the temperature is preferably 100°C to 400°C, and more preferably 120°C to 250°C. In the case of thermal imidization, the water generated by the imidization reaction is preferably removed from the system.

[0179] The catalyst imidization is performed, for example, by adding a basic catalyst and an acid anhydride to the solution containing a polymer having an amic acid ester structure, and stirring is preferably performed at -20°C to 250°C, and more preferably at 0°C to 180°C. The amount of the basic catalyst to be added is preferably 0.5 times to 30 times the molar equivalent of the amic acid group, and more preferably 2 times to 20 times the molar equivalent of the amic acid group. The amount of the acid anhydride to be added is preferably 1 times to 50 times the molar equivalent of the amic acid group, and more preferably 3 times to 30 times the molar equivalent of the amic acid group. The basic catalyst is exemplified by, but not limited to, pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, or the like. Pyridine is preferable because it has a moderate basicity to allow the reaction to proceed. The acid anhydride is exemplified by, but not limited to, acetic anhydride, trimellitic anhydride, or pyromellitic anhydride, or the like. Acetic anhydride is preferable because purification after the reaction is easy. The imidization rate of the catalyst imidization can be controlled by adjusting the amount of the catalyst, the reaction temperature, and / or the reaction time.

[0180] When the imidized polymer formed is recovered from the above-mentioned reaction solution, the reaction solution is simply poured into a solvent and precipitated. The solvent used for the precipitation is, for example, but not limited to, methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene or water, etc. After the polymer precipitated by pouring into the solvent is filtered and recovered, it can be dried at normal pressure or reduced pressure, at normal temperature or with heating. Alternatively, the polymer recovered by precipitation is dissolved in a solvent and subjected to re-precipitation recovery, and this operation is repeated 2 to 10 times, whereby impurities in the polymer can be reduced. The solvent used can be, for example, an alcohol or a ketone hydrocarbon, etc. If three or more kinds of solvents are selected from among these, the efficiency of purification can be further improved, and thus it is more desirable.

[0181] The solution viscosity of the first polymer (Al) or the second polymer (A2) of the present application is not particularly limited when the solution is configured to contain the first polymer (Al) or the second polymer (A2) at a concentration of 10 to 15 wt%, and the solution viscosity can be, for example, 10 to 1000 mPa-s from the viewpoint of easy handling. The solution viscosity (mPa-s) of the polymer is a value measured at 25°C using a good solvent for the polymer (for example, γ-butyrolactone or N-methyl-2-pyrrolidone, etc.) to prepare a polymer solution at a concentration of 10 to 15 wt%, and using an E-type rotational viscometer.

[0182] In some embodiments of the present application, preferably, the first polymer (Al) or the second polymer (A2) of the present application has a weight average molecular weight (Mw) of 1,000 to 500,000, more preferably 2,000 to 500,000, as measured by gel permeation chromatography (GPC) in terms of polystyrene. Further, preferably, the molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) as measured by GPC in terms of polystyrene is 15 or less, more preferably 10 or less. When the weight average molecular weight and the number average molecular weight of the polymer are in the above-mentioned molecular weight ranges, good alignment properties and stability of the liquid crystal display element can be ensured.

[0183] In some embodiments of the present application, when synthesizing the first polymer (Al) or the second polymer (A2) of the present application, the above-mentioned tetracarboxylic dianhydride component and the diamine component can be used, and a suitable end-capping agent can be used to synthesize a polymer of a terminal-capped type. The polymer of the terminal-capped type has an effect of improving the film hardness of the liquid crystal alignment film obtained by using the coating film, and improving the adhesion properties of the sealant and the liquid crystal alignment film. The terminal of the first polymer (Al) or the second polymer (A2) of the present application can be, for example, an amino group, a carboxyl group, an anhydride group, or a derivative of the above-mentioned groups. The amino group, the carboxyl group, the anhydride group, or the derivative of the above-mentioned groups can be obtained by a general condensation reaction, or by capping the terminal using the following end-capping agent. Similarly, the above-mentioned derivative can be obtained, for example, using the following end-capping agent.

[0184] The end-capping agent is, for example, but not limited to, an anhydride, a dicarbonate compound, a chlorocarbonyl compound, a monoamine compound, or a monoisocyanate compound, etc. The anhydride is, for example, but not limited to, acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexane dicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-((3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, or 4-ethynylphthalic anhydride. The dicarbonate compound is, for example, but not limited to, di-t-butyl dicarbonate, or diallyl dicarbonate, etc. The chlorocarbonyl compound is, for example, but not limited to, acryloyl chloride, methacryloyl chloride, or nicotinoyl chloride, etc. The monoamine compound is, for example, but not limited to, aniline, 2-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, or n-octylamine, etc. The monoisocyanate compound is, for example, but not limited to, ethyl isocyanate, phenyl isocyanate, or naphthyl isocyanate, etc.

[0185] The end-capping agent can be used alone or in a mixture of a plurality of kinds. In some embodiments of the present application, preferably, the amount of the end-capping agent used is 0.01 to 20 parts by mole, more preferably 0.01 to 10 parts by mole, based on 100 parts by mole of the total amount of the diamine component.

[0186] In some embodiments of the present application, the polymer component (A) of the liquid crystal alignment agent for the photo-alignment method of the present application can optionally further include other polymers. The other polymers are, for example, but not limited to, a polyester, a polyamide, a polyurea, a polyorganosiloxane, a cellulose derivative, a polyacetal, a polystyrene or a derivative thereof, a poly(styrene-phenylmaleimide) derivative, or a poly(meth)acrylate, etc.

[0187] Solvent (B)

[0188] From the viewpoint of forming a uniform thin film, the liquid crystal alignment agent takes the form of a coating liquid to produce a liquid crystal alignment film. Preferably, the liquid crystal alignment agent for the photo-alignment method of the present application is a coating liquid containing a polymer component (A) and a solvent (B). The concentration of the polymer component (A) in the liquid crystal alignment agent for the photo-alignment method can be appropriately changed based on the desired thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, the concentration of the polymer component (A) in the liquid crystal alignment agent for the photo-alignment method is preferably 1 wt% or more. From the viewpoint of the storage stability of the solution, the concentration of the polymer component (A) in the liquid crystal alignment agent for the photo-alignment method is preferably 10 wt% or less. The concentration of the polymer component (A) is desirably 2 wt% to 8 wt%. The content of the polymer component (A) in the liquid crystal alignment agent for the photo-alignment method can be appropriately changed by the coating method of the liquid crystal alignment agent and / or the film thickness of the desired liquid crystal alignment film, and the content of the polymer component (A) is preferably 2 wt% to 10 wt%, more preferably 3 wt% to 8 wt%.

[0189] The solvent (B) is, for example, an organic solvent, and the solvent (B) is not particularly limited as long as it uniformly dissolves the polymer component (A). The solvent (B) is, for example, but not limited to, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyl lactamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, 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, or N-cyclohexyl-2-pyrrolidone, and the above solvents are also referred to as good solvents. N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, or γ-butyrolactone is preferable. In some embodiments of the present application, based on the total amount of the solvent (B) in the liquid crystal alignment agent for the photo-alignment method being 100 wt%, the amount of the good solvent used is 20 wt% to 99 wt%, preferably 20 wt% to 90 wt%, more preferably 30 wt% to 80 wt%.

[0190] In some embodiments of the present invention, preferably, the solvent (B) comprises the aforementioned good solvent and a poor solvent that can improve the coatability and surface smoothness of the coating film during the coating of the liquid crystal alignment agent. Preferably, the total amount of solvent (B) in the liquid crystal alignment agent used in the photoalignment method is 100 wt%, and the amount of the poor solvent used is 1 wt% to 80 wt%, more preferably, the amount of the poor solvent used is 10 wt% to 80 wt%, and even more preferably, the amount of the poor solvent used is 20 wt% to 70 wt%. The type and amount of the poor solvent can be appropriately selected according to the coating apparatus, coating conditions, and / or coating environment of the liquid crystal alignment agent.

[0191] The undesirable solvents mentioned include, but are not limited to, 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 (butyl cellosolve), ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, and 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 monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, or diisobutyl ketone (2,6-dimethyl-4-heptanone), etc. Preferably, the undesirable solvent is diisobutylmethanol, 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, etc.

[0192] In some embodiments of the present invention, preferably, the solvent combination of the good solvent and the poor solvent is, for example, but not limited to, N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-dimethyllacticamide and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate. N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether acetate; N-ethyl-2-pyrrolidone with dipropylene glycol dimethyl ether; N,N-dimethyl lactamide with ethylene glycol monobutyl ether; N,N-dimethyl lactamide with propylene glycol diacetate; N-ethyl-2-pyrrolidone with diethylene glycol diethyl ether; N,N-dimethyl lactamide with diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone with diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone with propylene glycol monobutyl ether; N-methyl N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ- Butyrolactone with propylene glycol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutylmethanol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and propylene glycol diacetate; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and diisobutyl ketone; N-ethyl-2-pyrrolidone, γ-butyrolactone and diisobutyl ketone; or N-ethyl-2-pyrrolidone, N,N-dimethyllactic acid and diisobutyl ketone, etc.

[0193] The solvent (B) can be used alone or in combination with other solvents. In some embodiments of the invention, based on a total amount of 100 parts by weight of the polymer component (A), the amount of solvent (B) used is 800 to 4000 parts by weight, preferably 900 to 3500 parts by weight, and more preferably 1000 to 3000 parts by weight.

[0194] Additives (C)

[0195] In some embodiments of the present invention, the liquid crystal alignment agent used in the photoalignment method of the present invention further comprises an additive (C). The additive (C) includes, but is not limited to, adhesion promoters for improving the adhesion between the liquid crystal alignment film and the substrate or between the liquid crystal alignment film and the sealant, crosslinking compounds for improving the strength of the liquid crystal alignment film, compounds for promoting imidization, and dielectric or conductive materials for adjusting the dielectric constant or resistance of the liquid crystal alignment film.

[0196] The sealing aids include, but are not limited to, 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-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, and vinyltrimethoxysilane. Silane coupling agents such as methyl silane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, tris(3-trimethoxysilylpropyl)isocyanurate, or 3-isocyanatepropyltriethoxysilane. When using the aforementioned binding agent, based on the viewpoint of exhibiting good resistance to AC image retention, it is preferable that the amount of the binding agent used is from 0.1 to 30 parts by weight relative to 100 parts by weight of the total amount of polymer component (A) in the liquid crystal alignment agent used in the photoalignment method, and more preferably, the amount of the binding agent used is from 0.1 to 20 parts by weight.

[0197] Based on the viewpoint of exhibiting good resistance to AC remnants and effectively improving film strength, the crosslinking compound is a compound having ethylene oxide, propylene oxide, at least one group selected from the group consisting of the group shown in formula (E1) and the group shown in formula (E2), or a compound selected from the compound shown in formula (E3).

[0198]

[0199] In the aforementioned formula (E1), G 1 and G 2 Each of these independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or -CH2-OH. In the formula (E2), G 3 G represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. 4 This represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. In formula (E3), G 5 G represents an organic group with an aromatic ring and a (g1+g2) valence. 6 This indicates a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. g1 represents an integer from 1 to 6, and g2 represents an integer from 0 to 4.

[0200] In the aforementioned formula (E3), G 5 The (g1+g2) valence organic group having an aromatic ring is, for example, an (g1+g2) valence aromatic hydrocarbon group having 6 to 30 carbon atoms, an (g1+g2) valence organic group formed by direct or spaced linkages of an aromatic hydrocarbon group having 6 to 30 carbon atoms, or a (g1+g2) valence group having an aromatic heterocycle. The aromatic hydrocarbon is, for example, benzene or naphthalene. The aromatic heterocycle is, for example, the exemplified aromatic heterocycles with the specific nitrogen-containing structure described above. The linkage group is, for example, an alkylene group having 1 to 10 carbon atoms or a group from which one hydrogen atom is removed, or a divalent or trivalent cyclohexane, etc. Any hydrogen atom of the alkylene group may also be replaced by a fluorine atom or an organic group such as trifluoromethyl. In the formula (E3), G 6 Alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, or n-pentyl.

[0201] The ethylene oxide-containing compounds include, but are not limited to, N,N,N',N'-tetracyclooxypropyl-m-xylenediamine, 1,3-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetracyclooxypropyl-p-phenylenediamine, and compounds containing nitrogen atoms as shown in formulas (E4) to (E6).

[0202]

[0203] The compounds having an alkyl group are, for example, but not limited to, the compounds shown in formulas (E7) to (E16).

[0204]

[0205]

[0206]

[0207] In equation (E7), n represents 1 to 3. In equation (E13), n represents 1 to 3. In equation (E14), n represents 1 to 100. In equation (E15), R represents... "*" represents the bond position. In the above formula (E16), n represents 1 to 10.

[0208] The compounds having groups as shown in formula (E1) are, for example, but not limited to, the compounds shown in formulas (E1-1) to (E1-12).

[0209]

[0210]

[0211]

[0212] The compounds having groups as shown in formula (E2) are, for example, but not limited to, the compounds shown in formulas (E2-1) to (E2-4).

[0213]

[0214] In equation (E2-1), n ​​represents 2 to 16. In equation (E2-2), n represents 2 to 16.

[0215] The compounds having groups as shown in formula (E3) are, for example, but not limited to, the compounds shown in formulas (E3-1) to (E3-10).

[0216]

[0217] In some embodiments of the present invention, preferably, based on the total amount of the polymer component (A) in the liquid crystal alignment agent used in the photoalignment method being 100 parts by weight, the amount of the crosslinking compound used is from 0.5 parts by weight to 20 parts by weight. More preferably, based on the viewpoint of the progress of the crosslinking reaction and good resistance to AC image retention, the amount of the crosslinking compound used is from 1 part by weight to 15 parts by weight.

[0218] In some embodiments of the present invention, the compound used to promote imidization is a compound having a basic site [e.g., a primary amino group, an aliphatic heterocycle (such as a pyrrolidine skeleton), an aromatic heterocycle (such as an imidazole ring or an indole ring), or a guanidine group, etc.] (excluding the aforementioned crosslinking compounds and binding aids), or a compound that produces the basic site upon calcination. More preferably, the compound used to promote imidization is a compound that produces the basic site upon calcination, for example, an amino acid having a portion or all of its basic site as a protected amino acid. Specific examples of the aforementioned amino acids include glycine, alanine, cysteine, methionine, asparagine, glutamine, valine, leucine, phenylalanine, tyrosine, tryptophan, proline, hydroxyproline, arginine, histidine, lysine, or ornithine. For the purpose of promoting the formation of imidized compounds, more preferably, the compound for promoting imidization is N-α-(9-fluorenylmethoxycarbonyl)-N-τ-(tert-butoxycarbonyl)-L-histidine.

[0219] Liquid crystal photoalignment film and liquid crystal display element

[0220] The liquid crystal photoalignment film of the present invention is formed from the liquid crystal alignment agent used in the photoalignment method described above. The liquid crystal photoalignment film of the present invention can be used as a horizontally aligned or vertically aligned (VA type) liquid crystal photoalignment film, and is suitable as a liquid crystal alignment film for horizontally aligned liquid crystal display elements such as IPS or FFS types. The liquid crystal display element of the present invention includes the liquid crystal photoalignment film. The liquid crystal display element of the present invention can be manufactured, for example, by the methods described in steps (1) to (4) below, or steps (1) to (2) and (4).

[0221] Step (1): Apply liquid crystal alignment agent to the substrate.

[0222] Using a suitable coating method such as roll coating, spin coating, printing, or inkjet printing, the liquid crystal alignment agent for the photoalignment method of the present invention is coated on one side of a substrate having a patterned transparent conductive film. The substrate is not particularly limited; it only needs to be a highly transparent substrate, and glass or silicon nitride substrates can be used in combination with plastic substrates such as acrylic or polycarbonate substrates. Furthermore, in reflective liquid crystal display elements, if only a single-sided substrate is used, an opaque material such as a silicon wafer can be used, and the electrodes used can be made of light-reflective materials such as aluminum. Moreover, when manufacturing IPS or FFS type liquid crystal elements, the comb-type uses an electrode substrate composed of a patterned transparent conductive film or metal film and an opposing substrate without electrodes.

[0223] Methods for coating the liquid crystal alignment agent used in the photoalignment method onto a substrate and forming a film include screen printing, offset printing, flexographic printing, inkjet printing, and spray coating. Preferably, the film formation method utilizes inkjet coating.

[0224] Step (2): Calcination of the coated liquid crystal alignment agent

[0225] Step (2) is the calcination of the liquid crystal alignment agent coated on the substrate to form a film. After the liquid crystal alignment agent for photoalignment is coated onto the substrate, the solvent can be evaporated by heating means such as a hot plate, a thermally circulating oven, or an infrared oven, or thermal imidization of polyamic acid or polyamic acid ester can be performed. The drying and calcination steps performed after coating the liquid crystal alignment agent for photoalignment can be performed at any temperature and time, and multiple drying or calcination steps can be performed. The temperature of the drying step can be, for example, 40°C to 180°C. From the viewpoint of shortening the processing time, the drying step can be performed at 40°C to 150°C. The time of the drying step is not particularly limited, and it can be, for example, 1 minute to 10 minutes or 1 minute to 5 minutes. When thermal imidization of polyamic acid or polyamic acid ester is performed, after the drying step, a calcination step can be further performed at a temperature of, for example, 150°C to 300°C or 150°C to 250°C. The calcination step is not particularly time-limited, and can be 5 to 40 minutes or 5 to 30 minutes. If the film obtained after the calcination step is too thin, the reliability of the liquid crystal display element will be reduced. Therefore, preferably, the thickness of the film is 5 nm to 300 nm, and more preferably, the thickness of the film is 10 nm to 200 nm.

[0226] Step (3): Perform alignment treatment on the membrane obtained in step (2).

[0227] Step (3) involves performing alignment treatment on the film obtained in step (2), depending on the circumstances. That is, in horizontally aligned liquid crystal display elements such as IPS or FFS types, alignment treatment is performed on the film to impart alignment capability. On the other hand, in vertically aligned liquid crystal display elements such as VA or PSA types, the formed film can be used directly as a liquid crystal alignment film, but alignment treatment can also be performed on the film to impart alignment capability. Alignment treatment of the liquid crystal alignment film includes, but is not limited to, rubbing treatment or photoalignment treatment; preferably, photoalignment treatment. Photoalignment treatment, for example, involves irradiating the surface of the film with radiation already biased in a certain direction, and, depending on the circumstances, heating it at a temperature of 150°C to 250°C to impart liquid crystal alignment properties (also called liquid crystal alignment capability). The radiation can be ultraviolet or visible light with a wavelength of 100nm to 800nm. Preferably, the radiation is ultraviolet light with a wavelength of 100 nm to 400 nm, and more preferably, the radiation is ultraviolet light with a wavelength of 200 nm to 400 nm.

[0228] The radiation dose can be 1 mJ / cm². 2 Up to 10,000 mJ / cm 2 Preferably, the radiation dose is 100 mJ / cm². 2 Up to 5,000 mJ / cm 2 More preferably, the radiation dose is 100 mJ / cm². 2 Up to 1500mJ / cm 2 Preferably, the radiation dose is 100 mJ / cm². 2 Up to 1000mJ / cm 2 When using a general liquid crystal alignment agent, the light irradiation dose for the alignment treatment is 100 mJ / cm². 2 Up to 5000mJ / cm 2 However, the liquid crystal alignment agent used in the photoalignment method of the present invention can still form a liquid crystal photoalignment film in which variations (non-uniformity) in the liquid crystal alignment within the film surface are effectively suppressed, even if the amount of light irradiation during the alignment treatment is reduced. During irradiation with radiation, in order to improve the liquid crystal alignment, the substrate having the film can be heated at 50°C to 250°C simultaneously with irradiation. The liquid crystal photoalignment film produced in this manner allows the liquid crystal molecules to be stably aligned in a certain direction. Furthermore, the liquid crystal photoalignment film irradiated with polarized radiation in the above method can be contacted with a solvent, or the irradiated liquid crystal photoalignment film can be heat-treated.

[0229] The solvent used in the contact treatment is not particularly limited, as long as it can dissolve the decomposition products generated from the film after radiation irradiation. The solvent used in the contact treatment includes, but is not limited to, 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, or cyclohexyl acetate. From the viewpoint of versatility and safety, it is preferable that the solvent used in the contact treatment is water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate; more preferably, it is water, 1-methoxy-2-propanol, or ethyl lactate. The solvent used in the contact treatment can be used alone or in combination.

[0230] In some embodiments of the present invention, preferably, the temperature for heating the irradiated film is 50°C to 300°C, more preferably, the temperature for heating is 120°C to 250°C. Preferably, the heating time is 1 minute to 30 minutes.

[0231] Step (4): Fabrication of liquid crystal cells

[0232] Prepare two substrates with liquid crystal alignment films formed on their surfaces, and place liquid crystal between the two substrates facing each other. For example, the following two methods can be used. In the first method, firstly, arrange the two substrates facing each other with their liquid crystal alignment films facing each other, separated by a gap (intercellular space). Then, bond the peripheries of the two substrates together with a sealant, and then inject the liquid crystal composition to fill the intercellular space separated by the substrate surfaces and the sealant. After it contacts the film surface, seal the injection hole.

[0233] The second method is called the ODF (One Drop Fill) method. A UV-curable sealant is applied to predetermined positions on one of two substrates on which a liquid crystal alignment film is formed. Then, a liquid crystal composition is dropped onto multiple predetermined positions on the surface of the liquid crystal alignment film. Next, the other substrate is bonded with the liquid crystal alignment films facing each other, pressing the liquid crystal composition against the entire surface of the liquid crystal alignment film, bringing it into contact with the surface of the other liquid crystal alignment film. Then, the entire surface of the substrate is irradiated with UV light to harden the sealant. Preferably, when performing any of the above methods, the liquid crystal composition used is further heated to a temperature at which it becomes isotropic, and then slowly cooled to room temperature to remove the flow alignment during liquid crystal filling. Furthermore, when performing a friction treatment on the film, the two substrates are arranged facing each other at a predetermined angle to the friction direction of each film, for example, orthogonal or antiparallel. The sealant can be, for example, an epoxy resin containing a hardener and alumina spheres as spacers. The liquid crystal composition is, for example, a nematic liquid crystal or a lamellar liquid crystal, preferably a nematic liquid crystal.

[0234] A polarizing plate can be attached to the outer surface of the liquid crystal cell as needed to obtain a liquid crystal display element. The polarizing plate attached to the outer surface of the liquid crystal cell is, for example, a polarizing film that extends and aligns with polyvinyl alcohol while simultaneously absorbing iodine, and is called an "H film". The polarizing plate can be a polarizing plate sandwiched with a cellulose acetate protective film, or a polarizing plate composed of the H film itself.

[0235] The present invention will be further described with reference to the following embodiments, but it should be understood that the embodiments are for illustrative purposes only and should not be construed as limiting the implementation of the present invention.

[0236] [Synthesis Example 1] Diamine compound (b1-1-1)

[0237] 80 g (1 mol) of reactant A and 93 g (2.2 mol) of reactant B were dissolved in 1.5 L of acetonitrile, and then 126 g (3 mol) of potassium carbonate was added to obtain a mixture. Reactant A was 5-nitro-2(1H)-pyridinone, and reactant B was 1,4-bis(bromomethyl)benzene. The mixture was then heated to 80 °C and reacted for 4 hours. The resulting mixture was filtered, and the solid was collected. The solid was then mixed with 0.6 L of methanol at 50 °C and stirred for 1 hour. After cooling to room temperature, the mixture was filtered again, and the solid was collected. The solid collected from the second filtration was then dried under vacuum to obtain an intermediate product, as shown in Table 1.

[0238] 0.1 mol of the intermediate product was dissolved in 2.5 L of tetrahydrofuran to obtain a mixed solution. Then, 4 g of platinum-carbon (containing 10 wt% platinum) was added to the mixed solution to obtain a mixture. The mixture was heated to 40°C, and 20.0 g (0.4 mol) of hydrazine monohydrate was slowly added dropwise. The solution containing the mixture and hydrazine monohydrate was then heated to 60°C and stirred for 3.5 hours. The solution was then filtered, and the filtrate was collected. The filtrate was then filtered under reduced pressure to obtain a crude product. Finally, the crude product was dried under vacuum to obtain the diamine compound (b 1-1-1), as shown in Table 1.

[0239] [Synthetic Examples 2 to 6] Diamine compounds (b 1-1-2) to (b 1-1-6)

[0240] Synthetic Examples 2 to 6 were prepared in a manner similar to that of Synthetic Example 1, thereby obtaining diamine compounds (b 1-1-2) to (b 1-1-6), respectively, with the difference being that the types of compound A and / or compound B were changed, as shown in Table 1.

[0241] Table 1

[0242]

[0243]

[0244]

[0245]

[0246] [Preparation Example 1] First Polymer (A1)

[0247] A nitrogen inlet, stirrer, condenser, and thermometer were installed on a 500 mL four-necked conical flask, and nitrogen gas was introduced. Then, 0.005 mol (10 mol%) of compound b1-1-1, 0.03 mol (60 mol%) of compound b1-2-1, 0.01 mol (20 mol%) of compound b1-3-1, 0.005 mol (10 mol%) of compound b1-4-1, and 80 g of N-methyl-2-pyrrolidone were added, and the mixture was stirred at 25 °C until dissolved. Next, 0.05 mol (100 mol%) of compound a1-1-1 and 20 g of N-methyl-2-pyrrolidone were added, and the mixture was reacted at 25 °C for 2 hours to obtain a reaction solution. The reaction solution was poured into 1500 mL of water to precipitate the polymer. The precipitate was then filtered to obtain a filter cake. The filter cake was then washed with methanol and filtered again. This process was repeated three times to obtain a crude product. The crude product was then placed in a vacuum oven and dried at 60°C to obtain the first polymer (Al).

[0248] [Preparation Examples 2 to 8 and Comparative Preparation Examples 1 to 3] First Polymer (A1)

[0249] Preparation Examples 2 to 8 and Comparative Preparation Examples 1 to 3 were prepared using a method similar to that of Preparation Example 1, except that the types and amounts of tetracarboxylic acid dianhydride component (a1) and diamine component (b1) were changed in Preparation Examples 2 to 8 and Comparative Preparation Examples 1 to 3, as shown in Tables 2 and 3.

[0250] Table 2

[0251]

[0252]

[0253]

[0254]

[0255] Table 3

[0256]

[0257]

[0258] [Preparation Example 9] Second Polymer (A2)

[0259] A nitrogen inlet, stirrer, condenser, and thermometer were installed on a 500 mL four-necked conical flask, and nitrogen gas was introduced. Then, 0.04 mol (80 mol%) of compound b2-1, 0.01 mol (20 mol%) of compound b2-2, and 80 g of N-methyl-2-pyrrolidone were added, and the mixture was stirred at 25 °C until dissolved. Next, 0.05 mol (100 mol%) of compound a2-1 and 20 g of N-methyl-2-pyrrolidone were added, and the mixture was reacted at 25 °C for 2 hours to obtain a reaction solution. The reaction solution was poured into 1500 mL of water to precipitate the polymer. The precipitate was then filtered to obtain a filter cake. The filter cake was then washed with methanol and filtered again. This process was repeated three times to obtain a crude product. The crude product was then placed in a vacuum oven and dried at 60 °C to obtain the second polymer (A2).

[0260] [Preparation Examples 10 to 11] Second Polymer (A2)

[0261] Preparation Examples 10 and 11 were prepared by a method similar to that of Preparation Example 9, except that the types and amounts of tetracarboxylic acid dianhydride component (a2) and diamine component (b2) were changed in Preparation Examples 10 and 11, as shown in Table 4.

[0262] Table 4

[0263]

[0264]

[0265] [Example 1] Liquid crystal alignment agent, liquid crystal photoalignment film and liquid crystal display element used in photoalignment method

[0266] 100 parts by weight of the first polymer (A1) of Preparation Example 1 were mixed with 1200 parts by weight of N-methyl-2-pyrrolidone [as solvent (B)] at 25°C to obtain a liquid crystal alignment agent for photoalignment.

[0267] A glass substrate with electrodes is prepared, having a length of 30 mm, a width of 50 mm, and a thickness of 0.7 mm. Indium tin oxide (ITO) electrodes with a solid pattern are formed on the glass substrate to constitute the counter electrode. Then, a silicon nitride (SiN) film with a thickness of 500 nm is formed on the counter electrode using chemical vapor deposition (CVD). This silicon nitride film serves as an insulating film. Next, a pectinate pixel electrode formed from the patterned indium tin oxide (ITO) film is disposed on the silicon nitride film. The pixel electrode includes a first pixel and a second pixel, each having a length of 10 mm and a width of approximately 5 mm. At this point, the counter electrode and the pixel electrode are electrically insulated from each other by the silicon nitride film.

[0268] The pixel electrode is comb-shaped and is composed of multiple electrode elements whose central portions are bent into a "ㄑ" shape. Each electrode element has a short-side width of 3 μm and a spacing of 6 μm between each element. Because the pixel electrode forming each pixel is composed of multiple electrode elements whose central portions are bent into a "ㄑ" shape, each pixel is not rectangular but has a centrally bent shape, similar to the electrode elements, and approximates a bold "ㄑ" shape. Each pixel is divided into upper and lower parts by the central bent portion, thus each pixel has a first region located above the central bent portion and a second region located below the central bent portion.

[0269] Comparing the first and second regions of each pixel, the electrode elements of the pixel electrodes constituting the first and second regions are formed in different directions. Specifically, with the vertical line (Y-axis) on the glass substrate as a reference, in the first region of each pixel, the electrode elements of the pixel electrode are formed at an angle of +10° (clockwise), while in the second region of each pixel, the electrode elements of the pixel electrode are formed at an angle of -10° (counter-clockwise). In other words, in the first and second regions of each pixel, the directions of the rotational movement (planar switching) within the liquid crystal substrate caused by the applied voltage between the pixel electrode and the opposing electrode are opposite to each other.

[0270] The liquid crystal alignment agent used in the photoalignment method is filtered through a 1.0 μm filter and then coated onto the glass electrode using a spin coating method. Next, the glass substrate coated with the liquid crystal alignment agent is placed on a heating plate at 80°C and dried for 5 minutes. Then, it is baked in a hot air circulating oven at 230°C for 20 minutes to form a 100 nm thick film of the liquid crystal alignment agent on the glass substrate. The film is then irradiated with 254 nm ultraviolet light through a polarizing plate to form a liquid crystal photoalignment film, thus obtaining a first laminate containing the liquid crystal photoalignment film.

[0271] The liquid crystal alignment agent for the photoalignment method was filtered through a 1.0 μm filter and then spin-coated onto a glass substrate with an ITO film formed on the back and columnar spacers having a height of 4 μm. The glass substrate coated with the liquid crystal alignment agent was then dried on a heating plate at 80°C for 5 minutes, followed by baking in a hot air circulating oven at 230°C for 20 minutes to form a 100 nm thick film of the liquid crystal alignment agent on the glass substrate. The film was then irradiated with 254 nm ultraviolet light through a polarizing plate to form a liquid crystal photoalignment film, thus obtaining a second laminate containing the liquid crystal photoalignment film.

[0272] A sealant is printed on one of the first and second laminates. Then, the liquid crystal photoalignment films of the first and second laminates are bonded together with their alignment directions at 0°. The sealant is then hardened to obtain a laminate containing an injection port and liquid crystal cell holes communicating with the injection port. Next, liquid crystal MLC-2041 (manufactured by Merck) is injected into the liquid crystal cell holes using a depressurized injection method, and the injection port is sealed. The laminate is then heated at 110°C for 1 hour and left overnight to obtain a liquid crystal display element.

[0273] [Examples 2 to 16 and Comparative Examples 1 to 6] Liquid crystal alignment agent, liquid crystal photoalignment film and liquid crystal display element for photoalignment method

[0274] Examples 2 to 16 and Comparative Examples 1 to 6 were prepared using a method similar to that of Example 1 to obtain liquid crystal alignment agents, liquid crystal photoalignment films, and liquid crystal display elements for photoalignment. The difference was that Examples 2 to 16 and Comparative Examples 1 to 6 changed the types and / or amounts of the first polymer (A1), the second polymer (A2), and the solvent (B) in the liquid crystal alignment agent for photoalignment, as shown in Tables 5 to 7. The liquid crystal alignment agents for photoalignment in Examples 2 to 8 were composed of the first polymer (A1) and the solvent (B) of Examples 2 to 8. The liquid crystal alignment agents for photoalignment in Examples 9 to 16 were composed of the first polymer (A1) of Examples 2 to 8, the second polymer (A2) of Examples 9 to 11, and the solvent (B). The liquid crystal alignment agents for photoalignment in Comparative Examples 1 to 6 were composed of the first polymer (A1) of Comparative Examples 1 to 3, the second polymer (A2) of Examples 9 to 11, and the solvent (B).

[0275] [Evaluation Items]

[0276] The following description uses the liquid crystal display element of Example 1 as an example. The liquid crystal display elements of the other Examples 2 to 16 and Comparative Examples 1 to 6 are described in the same manner.

[0277] Charge mitigation characteristics: The liquid crystal display element of Example 1 is placed between two polarizing plates arranged perpendicularly across the polarizing axes. With the pixel electrode and the opposing electrode short-circuited and at the same potential, an LED backlight is lit from below the two polarizing plates. The arrangement angle of the liquid crystal display element of Example 1 is adjusted to minimize the brightness of the light penetrating the polarizing plates. Next, an AC voltage with a frequency of 30Hz and a rectangular waveform is applied to the liquid crystal display element of Example 1, and the VT curve (voltage-transmittance curve) at 23°C is measured simultaneously. The AC voltage with a relative transmittance of 23% is then calculated.

[0278] Then, an AC voltage with a relative transmittance of 23%, a frequency of 30Hz, and a rectangular waveform was applied to the liquid crystal display element of Embodiment 1 for 5 minutes, followed by a DC voltage of +1.0V for 30 minutes. After that, the DC voltage was turned off, and an AC voltage with a relative transmittance of 23%, a frequency of 30Hz, and a rectangular waveform was applied to the liquid crystal display element of Embodiment 1 again for 20 minutes.

[0279] The method for judging charge mitigation characteristics is as follows: immediately after applying a DC voltage to the liquid crystal display element, when the relative transmittance of the liquid crystal display element is above 30%, after driving with the DC voltage for 30 minutes, the lower the relative transmittance of the liquid crystal display element, the faster the charge mitigation of the liquid crystal display element is, indicating that it has good charge mitigation characteristics. The criteria for judging charge mitigation characteristics are as follows.

[0280] ◎: Relative transmittance < 26%

[0281] ○: 28% > Relative transmittance ≥ 26%

[0282] △: 30% > Relative transmittance ≥ 28%

[0283] X: Relative transmittance ≥ 30%

[0284] Table 5

[0285]

[0286]

[0287] Table 6

[0288]

[0289]

[0290] Table 7

[0291]

[0292] Referring to Tables 2 and 5 to 6, the liquid crystal alignment agents used in the photoalignment method of Examples 1 to 16 were all prepared using the first polymer (A1) of Preparation Examples 1 to 8. In particular, the first polymer (A1) of Preparation Examples 1 to 8 was prepared by combining a tetracarboxylic acid dianhydride component (a1) with a diamine component (b1) containing a diamine compound (b1-1). Therefore, the liquid crystal photoalignment film formed by the liquid crystal alignment agents used in the photoalignment method of Examples 1 to 16 can reduce the relative transmittance of the liquid crystal display element from more than 30% immediately after the DC voltage is applied to less than 28%, and even to less than 26%, after 30 minutes of DC voltage driving. This indicates that the liquid crystal display elements of Examples 1 to 16 have a fast charge recovery.

[0293] Referring to Tables 3 and 7, in contrast to Comparative Examples 1 to 6, the liquid crystal alignment agent used in the photoalignment method of Comparative Examples 1 to 6 was prepared using the first polymer (A1) of Comparative Preparation Examples 1 to 3. The diamine component (b1) used in the first polymer (A1) of Comparative Preparation Examples 1 to 3 did not contain the diamine compound (b1-1). Therefore, after being driven by DC voltage for 30 minutes, the relative transmittance of the liquid crystal display element of Comparative Examples 1 to 6 remained above 30%, indicating that the liquid crystal photoalignment film formed by the liquid crystal alignment agent used in the photoalignment method of Comparative Examples 1 to 6 could not impart the characteristic of fast charge reduction to the liquid crystal display element.

[0294] In summary, by using the first polymer (A1) obtained from the polyimide precursor containing the structure shown in formula (II), the liquid crystal photoalignment film formed by the liquid crystal alignment agent used in the photoalignment method of the present invention can impart the liquid crystal display element with the characteristic of slow and fast charge distribution, thus achieving the purpose of the present invention.

[0295] The above description is merely an embodiment of the present invention and should not be construed as limiting the scope of the present invention. Any simple equivalent changes and modifications made in accordance with the claims and description of the present invention shall still fall within the scope of the patent of the present invention.

Claims

1. A liquid crystal alignment agent for photoalignment, characterized in that: The liquid crystal alignment agent used in the photoalignment method comprises: Polymer component (A) includes a first polymer (A1), wherein the first polymer (A1) is selected from at least one of the group consisting of a polyimide precursor and an imidized polymer formed from the polyimide precursor; and Solvent (B); The polyimide precursor of the first polymer (A1) comprises the structure shown in formula (I). X 1 The representation is at least one of the groups consisting of the structures shown in equations (I-1) to (I-7), where "*" represents the bond position. X 11 X 12 X 13 and X 14 Each of these can independently represent hydrogen, halogen, alkyl (1 to 6 carbons), alkenyl (2 to 6 carbons), alkynyl (2 to 6 carbons), monovalent organic group (1 to 6 carbons containing fluorine), or phenyl. X 15 With X 16 Each can be used independently to represent hydrogen or methyl. X 2 Indicates an alkyl group having 1 to 4 carbon atoms. X 3 Indicates an alkyl group having 1 to 4 carbon atoms. Y 1 The divalent organic group representing the structure shown in formula (II) "*" represents the location of the bond. Ar represents a divalent aromatic group of phenyl, biphenyl, or naphthyl, wherein any hydrogen atom on the phenyl, biphenyl, or naphthyl group may be substituted by a monovalent group. M 1 and M 2 Each alkyl group has 1 to 4 carbon atoms and can be represented independently.

2. The liquid crystal alignment agent for photoalignment according to claim 1, characterized in that: X 1 The structure shown in equation (I-1) is selected from the structures shown in equations (I-1-1) to (I-1-6).

3. The liquid crystal alignment agent for photoalignment according to claim 1, characterized in that: X 1 The structure shown in equation (I-1) is selected from the structure shown in equation (I-1-1).

4. The liquid crystal alignment agent for photoalignment according to claim 1, characterized in that: M 1 and M 2 Each alkyl group has 1 to 2 carbon atoms and can be represented independently.

5. The liquid crystal alignment agent for the photoalignment method according to claim 1, characterized in that: The polymer component (A) further includes a second polymer (A2), and the second polymer (A2) is selected from at least one of the group consisting of a polyimide precursor and an imidized polymer formed from the polyimide precursor, and the polyimide precursor of the second polymer (A2) does not contain the structure shown in formula (I) of the first polymer (A1).

6. The liquid crystal alignment agent for photoalignment according to claim 5, characterized in that: The polyimide precursor of the second polymer (A2) is formed by reacting a reaction composition comprising a tetracarboxylic dianhydride component (a2) and a diamine component (b2), wherein the tetracarboxylic dianhydride component (a2) comprises a tetracarboxylic dianhydride compound having the structure shown in formula (III). Z 11 "*" represents a single bond, and "*" represents the bond position.

7. The liquid crystal alignment agent for photoalignment according to claim 6, characterized in that: The diamine component (b2) includes a diamine compound having a nitrogen-containing structure, wherein the nitrogen atom structure of the diamine compound having a nitrogen-containing structure is selected from at least one of the group consisting of nitrogen-containing heterocycles, secondary amino groups and tertiary amino groups.

8. A liquid crystal photoalignment film, characterized in that: The liquid crystal photoalignment film is formed from a liquid crystal alignment agent used in the photoalignment method as described in any one of claims 1 to 7.

9. A liquid crystal display element, characterized in that: The liquid crystal display element includes the liquid crystal photoalignment film as described in claim 8.

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