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

Abstract

The invention provides a liquid crystal alignment agent for a light alignment method, a liquid crystal alignment film formed by using the liquid crystal alignment agent, and a liquid crystal display component comprising the liquid crystal alignment film, wherein the liquid crystal alignment agent can reduce flicker degree after high-voltage driving. The liquid crystal alignment agent comprises a polymer (A) with a specific structure, a polymer (B) with another specific structure and a solvent (C).

Description

Technical Field

[0001] The present invention relates to a liquid crystal alignment agent for photo-alignment method, and in particular provides a liquid crystal alignment agent for photo-alignment method that can reduce flicker after high voltage driving, a liquid crystal alignment film formed using the liquid crystal alignment agent, and a liquid crystal display component including the liquid crystal alignment film. Background Art

[0002] Conventional liquid crystal display units are widely used as display components in personal computers, smartphones, mobile phones, and television sets. A liquid crystal display unit may include, for example, a liquid crystal layer sandwiched between a component substrate and a color filter substrate, pixel electrodes and a common electrode for applying an electric field to the liquid crystal layer, an alignment film for controlling the alignment of the liquid crystal molecules in the liquid crystal layer, and thin-film transistors (TFTs) for switching the electronic signals supplied to the pixel electrodes. Known methods for driving liquid crystal molecules include longitudinal electric field methods such as the TN (Twisted Nematic) method and the VA (Vertical Alignment) method, and transverse electric field methods such as the IPS (In-Plane Switching) method and the FFS (Fringe Field Switching) method.

[0003] At present, the most popular liquid crystal alignment film in the industry is a film surface formed on an electrode substrate and composed of polyamic acid and / or polyimide obtained by imidization, which is rubbed in one direction with a cloth such as cotton, nylon or polyester. Friction treatment is a simple and highly productive industrial method. However, with the high performance, high precision and large-scale development of liquid crystal display components, the surface of the alignment film is scratched by dust, mechanical force and static electricity generated by the friction treatment, which leads to various problems such as unevenness within the alignment treatment surface. As an alignment treatment method that replaces the friction treatment, there is a known photoalignment method that imparts liquid crystal alignment ability by irradiating polarized radiation. With respect to the photoalignment method, Japanese Patent Laid-Open No. 9-297313 has disclosed methods that utilize photoisomerization reactions, photocrosslinking reactions or photodecomposition reactions.

[0004] In recent years, LCDs have become increasingly popular in fields requiring high resolution and fast response times, such as medical equipment, aerospace, image processing, and industrial control. These applications require displays that can quickly and accurately display high-resolution images and data while also being able to withstand extreme environmental conditions. Therefore, driving LCDs with high voltages provides higher pixel density and faster refresh rates, meeting the demands of these specialized applications.

[0005] However, a liquid crystal display device containing a conventional liquid crystal alignment film produced by a photo-alignment method has a problem of excessive flicker when driven at a high voltage, and thus cannot meet application requirements. Summary of the Invention

[0006] In view of this, one aspect of the present invention provides a liquid crystal alignment agent for photo-alignment method, comprising a polymer (A), a polymer (B), and a solvent (C). The liquid crystal alignment film formed using this liquid crystal alignment agent can reduce the flicker of liquid crystal display devices after high voltage driving.

[0007] Another aspect of the present invention is to provide a liquid crystal alignment film formed using the liquid crystal alignment agent used in the above-mentioned photo-alignment method.

[0008] Another aspect of the present invention is to provide a liquid crystal display unit comprising the aforementioned liquid crystal alignment film and having a low brightness change rate after driving.

[0009] According to the above aspect of the present invention, a liquid crystal alignment agent for a photo-alignment method is provided, and the liquid crystal alignment agent comprises a polymer (A), a polymer (B), and a solvent (C).

[0010] Polymer (A)

[0011] The polymer (A) of the present invention may be at least one polymer selected from the group consisting of a polyimide precursor obtained by reacting a tetracarboxylic dianhydride component (a1) and a diamine component (a2), and an imidized polymer of a polyimide precursor. For example, polymer (A) may include a polyimide precursor having an imide precursor structure such as polyamic acid and polyamic acid ester, and / or an imidized product of such a polyimide precursor (i.e., a polyimide).

[0012] The polyimide precursor of polymer (A) may comprise a structure represented by the following formula (I):

[0013]

[0014] In formula (I), X1 is at least one selected from the group consisting of the structures represented by the following formulae (I-1) to (I-7), wherein "*" represents a bonding position; and X2 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms:

[0015]

[0016] In formula (I-1), X 11 、X 12 、X 13 With X 14Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. 15 With X 16 Each independently represents a hydrogen atom or a methyl group.

[0017] If the polymer (A) does not contain the structure represented by formula (I), the liquid crystal alignment film formed by the liquid crystal alignment agent may have a problem of excessive flicker after high voltage driving.

[0018] Tetracarboxylic dianhydride component (a1)

[0019] In the present invention, the tetracarboxylic dianhydride component (a1) that reacts with the diamine component (a2) may be a tetracarboxylic dianhydride compound, or a tetracarboxylic dianhydride derivative such as a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester, or a tetracarboxylic dianhydride dihalide. The tetracarboxylic dianhydride component (a1) may be a single tetracarboxylic dianhydride compound or a derivative thereof, or a combination of multiple tetracarboxylic dianhydride compounds may be used.

[0020] The tetracarboxylic dianhydride component (a1) may include an alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11) and other tetracarboxylic dianhydrides (a1-2).

[0021] Alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11)

[0022] The tetracarboxylic dianhydride component (a1) used to react to obtain the polymer (A) may include an alicyclic tetracarboxylic dianhydride (a1-1) or a derivative thereof as shown in the following formula (A11). The alicyclic tetracarboxylic dianhydride (a1-1) or a derivative thereof shown in formula (A11) may be composed of a single tetracarboxylic dianhydride or a derivative thereof, or may be composed of a plurality of tetracarboxylic dianhydrides or derivatives thereof. In the present invention, the alicyclic tetracarboxylic dianhydride (a1-1) shown in formula (A11) may be, 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 these four carboxyl groups are bonded to an aromatic ring. Alternatively, it is not necessary to be composed solely of an alicyclic structure, and a portion thereof may also have a chain hydrocarbon structure or an aromatic ring structure. The aromatic tetracarboxylic dianhydride may be, 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, it does not need to be composed solely of an aromatic ring structure; a portion thereof may have a chain hydrocarbon structure or an alicyclic structure. Non-cyclic aliphatic tetracarboxylic dianhydride may be, for example, an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. However, it does not need to be composed solely of a chain hydrocarbon structure; a portion thereof may have an alicyclic structure or an aromatic ring structure:

[0023]

[0024] In formula (A11), X1 can be selected from at least one of the following structures represented by formula (I-1) to formula (I-7), and "*" represents a bonding position:

[0025]

[0026]

[0027] In formula (I-1), X 11 、X 12 、X 13 With X 14 Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. 15 With X 16 Each independently represents a hydrogen atom or a methyl group.

[0028] In some embodiments, X1 may represent the structures shown in the following formulas (I-1-1) to (I-1-6):

[0029]

[0030] Preferably, X1 represents the structure represented by formula (I-1-1). When X1 represents the structure represented by formula (I-1-1), the flicker of the liquid crystal display unit containing the liquid crystal alignment film formed therewith after high voltage driving can be further improved.

[0031] Based on 100 mol of the total usage of the tetracarboxylic dianhydride component (a1), the usage of the alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11) is 30 mol to 100 mol, preferably 40 mol to 100 mol, and more preferably 50 mol to 100 mol.

[0032] When the tetracarboxylic dianhydride component (a1) does not include the alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11), the liquid crystal display unit containing the liquid crystal alignment film formed therefrom still has the problem of excessive flicker after high voltage driving.

[0033] Other tetracarboxylic dianhydrides (a1-2)

[0034] Other tetracarboxylic dianhydrides (a1-2) may include tetracarboxylic dianhydride compounds represented by the following formula (A12) and derivatives thereof:

[0035]

[0036] In formula (A12), X1′ may represent the structures shown in the following formulas (A12-1) to (A12-32), wherein “*” represents the bonding position:

[0037]

[0038]

[0039]

[0040]

[0041] In formula (A12-5) and formula (A12-6), X 11 ′ and X 12 'respectively independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl or amide, and multiple X 12 ' may be the same as or different from each other. a1 in formula (A12-5) represents an integer of 0 or 1; a1 in formula (A12-6) represents an integer of 0 or 1. In formula (A12-14), X 13 ' independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, and multiple X 13 ' can be the same or different from each other. Based on the viewpoint of liquid crystal alignment, X 13 ' preferably represents a hydrogen atom, a halogen atom, a methyl group or an ethyl group, and more preferably represents a hydrogen atom or a methyl group.

[0042] In some specific examples, the aforementioned formula (A12-5) and formula (A12-6) may include but are not limited to the following structures:

[0043]

[0044]

[0045]

[0046] The aforementioned other tetracarboxylic dianhydrides (a1-2) may be used alone or in combination of two or more.

[0047] Based on 100 mol of the total usage of the tetracarboxylic dianhydride component (a1), the usage of the other tetracarboxylic dianhydride (a1-2) is 0 mol to 70 mol, preferably 0 mol to 60 mol, and more preferably 0 mol to 50 mol.

[0048] Diamine component (a2)

[0049] The diamine component (a2) may include a diamine compound (a2-1). In addition, the diamine component (a2) may optionally include a diamine compound (a2-2) and a diamine compound (a2-3).

[0050] Diamine compound (a2-1)

[0051] The diamine compound (a2-1) is a compound represented by the following formula (A21):

[0052]

[0053] If the diamine component (a2) does not include the diamine compound (a2-1) represented by formula (A21), the liquid crystal display unit containing the liquid crystal alignment film formed therefrom still has the problem of excessive flicker after high voltage driving.

[0054] Based on 100 mol of the total usage of the diamine component (a2), the usage of the diamine compound (a2-1) may be 5 mol to 45 mol, preferably 7 mol to 42 mol, and more preferably 10 mol to 40 mol.

[0055] Diamine compound (a2-2)

[0056] The diamine compound (a2-2) may include a diamine compound represented by the following formula (A22-1) or formula (A22-2):

[0057]

[0058] In formula (A22-1), Y 31 represents a divalent organic group as shown in the following formula (A22-3). Multiple Y32s each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. In formula (A22-2), multiple Y 33 Each independently represents a divalent organic group represented by the following formula (A22-3′):

[0059]

[0060] In formula (A22-3), Ar each independently represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring, and the hydrogen atoms of the benzene ring, the biphenyl structure, or the naphthalene ring may be substituted with a monovalent substituent or may be unsubstituted; Y 31 ' represents -(CH2) n -, n represents an integer from 2 to 18, and -(CH2) n At least one -CH2- in - may be substituted by -O-, -C(=O)- or -OC(=O)- or may be unsubstituted; p1 represents an integer of 0 or 1; "*" represents a bonding position.

[0061] In formula (A22-3′), Ar′ independently represents a divalent benzene ring or a biphenyl structure, and the hydrogen atoms of the benzene ring or biphenyl structure may be substituted with a monovalent substituent or may be unsubstituted; Y 33 ' represents -(CH2) n -, n represents an integer from 2 to 18, and -(CH2) n At least one -CH2- in - may be substituted by -O-, -C(=O)- or -OC(=O)- or may be unsubstituted; p2 represents an integer of 0 or 1; "*" represents a bonding position.

[0062] The monovalent substituent group of the aforementioned benzene ring, biphenyl structure, or naphthalene ring may be, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkenyl group having 2 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group having 1 to 10 carbon atoms, a cyano group, or a nitro group.

[0063] From the perspective of improving the liquid crystal alignment, the divalent organic group represented by formula (A22-3) preferably includes groups represented by the following formulas (A22-3-1) to (A22-3-16), wherein "*" represents the bonding position:

[0064]

[0065]

[0066]

[0067] In formula (A22-3-14), each of m independently represents an integer of 1 to 3.

[0068] From the viewpoint of improving the liquid crystal alignment, the divalent organic group represented by formula (A22-3′) may preferably include groups represented by formulae (A22-3-7) to (A22-3-16).

[0069] When the diamine compound (a2-2) comprises a plurality of diamine compounds as shown in formula (A22-1), it is preferably Y in formula (A22-1). 31 The diamine compounds represented by formula (A22-3-1) to formula (A22-3-14) and Y in formula (A22-1) 31 This represents a combination of diamine compounds of formula (A22-3-15) to formula (A22-3-16).

[0070] In some specific examples, the diamine compound represented by the aforementioned formula (A22-2) may include, but is not limited to, diamine compounds represented by the following formulas (A22-2-1) to (A22-2-5):

[0071]

[0072]

[0073] The aforementioned diamine compounds (a2-2) may be used alone or in combination of two or more.

[0074] Based on 100 mol of the total usage of the diamine component (a2), the usage of the diamine compound (a2-2) may be 25 mol to 93 mol, preferably 38 mol to 90 mol, and more preferably 50 mol to 87 mol.

[0075] Other diamine compounds (a2-3)

[0076] In addition to the aforementioned diamine compound (a2-1) and diamine compound (a2-2), the diamine component (a2) used to obtain the polymer (A) may optionally further include other diamine compounds (a2-3). For example, other diamine compounds (a2-3) may include but are not limited to: 4,4′-diaminoazobenzene or diamine compounds represented by the following formulas (A23-1) to (A23-3), etc., which have a photoalignment group; 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol or 4,6-diaminoresorcinol; 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid or diamine compounds represented by the following formulas (A23-4) to (A23-7), etc., which have 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-dihydroindene-5-amine or 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; diamine compounds having a urea bond such as the diamine compounds represented by the following formulas (A23-8) to (A23-10); diamine compounds having an amide bond such as the diamine compounds represented by the following formulas (A23-11) to (A23-13); diamine compounds having a photopolymerizable group at the end such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallylaniline; diamine compounds having a photopolymerizable group such as the diamine compounds represented by the following formulas (A23-14) to (A23-15); A diamine compound having an oxazoline structure; a diamine compound having an amino group as shown in the following formula (A23-16); and 4-amino-N-methylphenethylamine:

[0077]

[0078]

[0079]

[0080] In formula (A23-4), Y 51 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 from 0 to 4, and (m1+m2) represents an integer from 1 to 4. In formula (A23-5), m3 and m4 each independently represent an integer from 1 to 5. In formula (A23-6), Y 52 represents a linear or branched alkyl group having 1 to 5 carbon atoms; m5 represents an integer from 1 to 5. In formula (A23-7), Y 53 and Y 54 Each independently 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-; m6 represents an integer from 1 to 4.

[0081] The aforementioned other diamine compounds (a2-3) may be used alone or in combination of two or more.

[0082] Based on 100 mol of the total usage of the diamine component (a2), the usage of the other diamine compounds (a2-3) may be 0 mol to 68 mol, preferably 0 mol to 52 mol, and more preferably 0 mol to 37 mol.

[0083] Polymer (B)

[0084] In addition to the aforementioned polymer (A), the liquid crystal alignment agent of the present invention further comprises a polymer (B) selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic dianhydride component (b1) and a diamine component (b2), and an imidized polymer (i.e., a polyimide) of the polyimide precursor. For example, polymer (B) may include, but is not limited to, at least one polymer selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic dianhydride component (b1) and a diamine component (b2) that does not contain the aforementioned specific diamine compound, and an imidized polymer (i.e., a polyimide) of the polyimide precursor. Specific examples of the aforementioned polyimide precursor may include, for example, polyamic acid or polyamic acid ester. The polymer (B) may be used alone or in combination.

[0085] The usage ratio of polymer (A) to polymer (B) (ie, the mass ratio of [polymer (A)] / [polymer (B)]) may be 10 / 90 to 90 / 10, preferably 20 / 80 to 90 / 10, and more preferably 20 / 80 to 80 / 20.

[0086] The polyimide precursor of polymer (B) comprises a structure represented by the following formula (II):

[0087]

[0088] In formula (II), X3 represents a tetravalent organic group; and X4 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0089] If the polymer (B) does not contain the structure of formula (II), the liquid crystal alignment film formed by the liquid crystal alignment agent may have a problem of excessive flicker after high voltage driving.

[0090] Tetracarboxylic dianhydride component (b1)

[0091] The tetracarboxylic dianhydride component (b1) used to obtain the polymer (B) may include, for example, but not limited to, a non-cyclic aliphatic tetracarboxylic dianhydride compound, an alicyclic tetracarboxylic dianhydride compound, an aromatic tetracarboxylic dianhydride compound, or derivatives of these compounds. Specific examples of the non-cyclic aliphatic tetracarboxylic dianhydride compound, the alicyclic tetracarboxylic dianhydride compound, and the aromatic tetracarboxylic dianhydride compound may include, for example, the tetracarboxylic dianhydride compounds exemplified for the aforementioned polymer (A). Preferably, the tetracarboxylic dianhydride component (b1) may include an alicyclic tetracarboxylic dianhydride or a derivative thereof as shown in the above formula (A11), or a tetracarboxylic dianhydride compound or a derivative thereof as shown in the above formula (A12) and X1′ represents a structure shown in formula (A12-1) to formula (A12-6). The tetracarboxylic dianhydride component (b1) may be used alone or in combination.

[0092] In order to further improve the flicker after high voltage driving, the tetracarboxylic dianhydride component (b1) preferably comprises a tetracarboxylic dianhydride compound (hereinafter referred to as tetracarboxylic dianhydride compound (b1-1)) as shown in the above formula (A12) and X1′ represents a structure shown in the following formula (III):

[0093]

[0094] In the above formula (III), Z 11 represents a single bond; and “*” represents a bonding position.

[0095] The aforementioned tetracarboxylic dianhydride compound (b1-1) may be used alone or in combination of two or more.

[0096] More preferably, the tetracarboxylic dianhydride component (b1) comprises a tetracarboxylic dianhydride compound represented by the following formula (IV):

[0097]

[0098] Based on 100 mol of the total usage of the tetracarboxylic dianhydride component (b1), the usage of the tetracarboxylic dianhydride compound (b1-1) may be 30 mol to 100 mol, preferably 40 mol to 100 mol, and more preferably 50 mol to 100 mol.

[0099] If the tetracarboxylic dianhydride component (b1) comprises a tetracarboxylic dianhydride compound (b1-1) having a structure represented by formula (III), the flicker after high voltage driving of a liquid crystal display unit containing a liquid crystal alignment film formed therefrom can be further improved.

[0100] Diamine component (b2)

[0101] The diamine component (b2) used to obtain the polymer (B) may include a diamine compound (b2-1) represented by the following formula (B21):

[0102]

[0103] If the diamine component (b2) does not include the diamine compound (b2-1) represented by the above formula (B21), the liquid crystal display unit containing the liquid crystal alignment film formed therefrom still has the problem of excessive flicker after high voltage driving.

[0104] Based on 100 mol of the total usage of the diamine component (b2), the usage of the diamine compound (b2-1) may be 3 mol to 100 mol, preferably 5 mol to 100 mol, and more preferably 7 mol to 100 mol.

[0105] In addition, the diamine component (b2) may include, but is not limited to, the aforementioned diamine component (a2), or a diamine compound having at least one nitrogen-containing structure selected from the group consisting of a nitrogen-containing heterocycle, a secondary amine group, and a tertiary amine group (hereinafter referred to as diamine compound (b2-2)). However, the diamine component (b2) does not include the aforementioned diamine compound (a2-1).

[0106] Diamine component (b2-2)

[0107] The diamine compound (b2-2) having the above-mentioned specific nitrogen-containing atom structure may have a nitrogen-containing heterocyclic ring, such as pyrrole, imidazole, pyrazole, triazole, pyridine, pyrim ... Pyril Indole, benzimidazole, purine, quinoline, isoquinoline, chloridine, quinolone phenanthene, tie three Carbazole, acridine, piperidine, piperidine Pyrrolidine or hexamethyleneimine, etc. Among them, pyridine, pyrimidine, pyrrolidine Piperidine, piperidine Quinoline, carbazole or acridine is preferred.

[0108] The diamine compound (b2-2) having the above-mentioned specific nitrogen-containing atom structure may include a secondary amine group and a tertiary amine group as shown in the following formula (B22):

[0109]

[0110] In formula (B22), Z represents a hydrogen atom or an alkyl group, cycloalkyl group, or aryl group having 1 to 10 carbon atoms; "*" represents the bonding position to the hydrocarbon group.

[0111] The alkyl group represented by Z may include, but is not limited to, methyl, ethyl, or propyl; the cycloalkyl group represented by Z may include, but is not limited to, cyclohexyl; and the aryl group represented by Z may include, but is not limited to, phenyl or tolyl. Z is preferably a hydrogen atom or a methyl group.

[0112] Specific examples of the diamine compound (b2-2) having the above-mentioned specific nitrogen-containing atom structure include: 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperidin 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, diamine compounds represented by the following formulas (B22-1) to (B22-8), or diamine compounds represented by the following formulas (B22-9) to (B22-26):

[0113]

[0114]

[0115]

[0116]

[0117]

[0118] The diamine component (b2) can be used alone or in combination of two or more.

[0119] Based on 100 mol of the total usage of the diamine component (b2), the usage of the diamine compound (b2-2) may be 3 mol to 90 mol, preferably 5 mol to 80 mol, and more preferably 7 mol to 70 mol.

[0120] If the diamine component (b2) contains at least one diamine compound (b2-2) having a nitrogen atom structure selected from the group consisting of a nitrogen-containing heterocyclic ring, a secondary amino group, and a tertiary amino group, the flicker after high-voltage driving of a liquid crystal display unit containing a liquid crystal alignment film formed therefrom can be further improved.

[0121] Method for producing polymers

[0122] The manufacture of polymer (A) or polymer (B) can be carried out by making the aforementioned diamine component and tetracarboxylic dianhydride component carry out (condensation polymerization) reaction in a solvent. When a part of polymer (A) or polymer (B) has an amic acid structure, for example, by making the tetracarboxylic dianhydride component react with the diamine component to obtain a polymer with an amic acid structure (i.e., polyamic acid). The aforementioned solvent is not particularly limited, and it only needs to be able to dissolve the formed polymer. For example, the specific example of the solvent may include but is 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. In some specific examples, when the solvent solubility of the polymer is high, the solvent may include methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a solvent as shown in the following formula (D-1) to formula (D-3). In formula (D-1), Z1 represents an alkyl group having 1 to 3 carbon atoms. In formula (D-2), Z2 represents an alkyl group having 1 to 3 carbon atoms. In formula (D-3), Z3 represents an alkyl group having 1 to 4 carbon atoms:

[0123]

[0124] The aforementioned solvents can be used alone or in combination. Secondly, even if the solvent is insoluble in the polymer, it can still be mixed with the above-mentioned solvents within the range that the generated polymer will not precipitate. When the diamine component and the tetracarboxylic dianhydride component react in a solvent, the reaction can be carried out at any concentration, but preferably 1wt% to 50wt%, and more preferably 5wt% to 30wt%. The reaction can also be carried out at a high concentration initially, and then additional solvent is added. When the reaction is carried out, the ratio of the total moles of the diamine component to the total moles of the tetracarboxylic dianhydride component is preferably 0.8 to 1.2. Similar to a general polycondensation reaction, the closer this molar ratio is to 1.0, the greater the molecular weight of the polymer (A) or polymer (B) formed.

[0125] A polymer having an amide ester structure can be obtained, for example, by the following conventional methods: (1) a method in which the polyamide acid obtained by the above method is further reacted with an esterifying agent, (2) a method in which a tetracarboxylic acid diester compound is reacted with a diamine compound, or (3) a method in which a tetracarboxylic acid diester dihalide is reacted with a diamine compound.

[0126] The imide compound in polymer (A) or polymer (B) contained in the liquid crystal alignment agent of the present invention can be obtained, for example, by subjecting the polymer obtained above to a dead cycle. In the imide compound, the dead cycle ratio (also referred to as the imidization ratio) of the functional groups possessed by the amic acid groups or their derivatives does not necessarily need to be 100%; the imidization ratio can be arbitrarily adjusted depending on the application and / or purpose.

[0127] The imide product can be obtained by, for example, thermal imidization by directly heating the polymer solution obtained by the above reaction, or catalytic imidization by adding a catalyst to the polymer solution. When thermal imidization is performed in solution, the temperature is preferably 100°C to 400°C, and more preferably 120°C to 250°C. During thermal imidization, it is preferred to remove water generated by the imidization reaction from the system.

[0128] The aforementioned catalytic imidization can be carried out, for example, by adding a basic catalyst and an acid anhydride to the polymer solution obtained by the reaction, preferably with stirring at -20°C to 250°C, and more preferably at 0°C to 180°C. The amount of the basic catalyst added is preferably 0.5 to 30 times the molar ratio of the amic acid group, and more preferably 2 to 20 times; the amount of the acid anhydride added is preferably 1 to 50 times the molar ratio of the amic acid group, and more preferably 3 to 30 times. Specific examples of basic catalysts include, but are not limited to, pyridine, triethylamine, trimethylamine, tributylamine, or trioctylamine. Pyridine is particularly preferred due to its moderate alkalinity for the reaction. Specific examples of acid anhydrides include, but are not limited to, acetic anhydride, trimellitic anhydride, or pyromellitic anhydride. Using acetic anhydride is particularly preferred because it facilitates purification after the reaction. The imidization rate of the catalytic imidization can be controlled by adjusting the catalyst amount, reaction temperature, and / or reaction time.

[0129] When the imide formed is recovered from the imidization reaction solution, the reaction solution is put into a solvent and precipitated. The solvent used for precipitation may include, but is not limited to, methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone ...

[0130] After filtering and recovering the polymer precipitated from the solvent, it can be dried at room temperature or under normal pressure or reduced pressure. Alternatively, the recovered precipitated polymer can be dissolved in a solvent again and reprecipitated and recovered. This operation can be repeated 2 to 10 times to reduce impurities in the polymer. The solvent used can be, for example, an alcohol or a ketone hydrocarbon. Using three or more of the selected solvents can further improve the efficiency of the refining, which is more ideal.

[0131] Solution viscosity and molecular weight of polymers

[0132] When prepared into a 10 wt % to 15 wt % solution, the concentration of the polymer (A) or polymer (B) of the present invention is not particularly limited. For ease of handling, the concentration of the solution can be, for example, 10 mPa·s to 1000 mPa·s. The viscosity (mPa·s) of the polymer solution is the value measured at 25°C using an E-type rotational viscometer using a good solvent for the polymer (e.g., γ-butyrolactone or N-methyl-2-pyrrolidone) to prepare a 10 wt % to 15 wt % polymer solution.

[0133] The weight average molecular weight (M) of the polymer (A) or polymer (B) of the present invention is measured by gel permeation chromatography (GPC) in terms of polystyrene. w) is preferably 1,000 to 500,000, and more preferably 2,000 to 500,000. w The number average molecular weight (M) of the polystyrene was measured by GPC. n ) ratio expressed as the molecular weight distribution (M w / M n ) is preferably less than 15, and more preferably less than 10. When the molecular weight of the polymer is within the aforementioned molecular weight range, it can ensure good alignment and stability of the liquid crystal display device.

[0134] Capping agent

[0135] When synthesizing the polymer (A) or polymer (B) of the present invention, the tetracarboxylic dianhydride component and the diamine component as described above can be used, and an appropriate end-capping agent can be used to synthesize an end-sealed polymer. The end-sealed polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by using the coating, and improving the sealing properties of the sealant and the liquid crystal alignment film. The end of the polymer (A) or polymer (B) of the present invention may, for example, contain an amino group, a carboxyl group, an acid anhydride group or a derivative thereof. The amino group, carboxyl group, acid anhydride group or a derivative thereof can be obtained by a general condensation reaction, or by sealing the end using an end-capping agent described later. Similarly, the aforementioned derivatives can be obtained, for example, using the following end-capping agent.

[0136] For example, the end-capping agent may include, but is not limited to, acetic anhydride, maleic anhydride, neddic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic 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; dibutyl dicarbonate or diallyl dicarbonate; Carbonic acid diester compounds; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride or nicotinyl chloride; monoamine compounds such as 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; monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate or naphthyl isocyanate, etc.

[0137] The blocking agents may be used alone or in combination of two or more.

[0138] Based on 100 parts by mole of the total diamine component, the amount of the capping agent used is preferably 0.01 parts by mole to 20 parts by mole, and more preferably 0.01 parts by mole to 10 parts by mole.

[0139] Other polymers

[0140] The liquid crystal alignment agent of the present invention comprises a polymer (A), a polymer (B), and a solvent (C). In addition to polymers (A) and (B), the liquid crystal alignment agent of the present invention may optionally comprise other polymers. Examples of such other polymers include, but are not limited to, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivatives, or poly(meth)acrylates.

[0141] Solvent (C)

[0142] Based on 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. The liquid crystal alignment agent of the present invention is preferably a coating liquid containing the above-mentioned polymer component and an organic solvent (i.e., the aforementioned solvent (C)). Among them, based on the set thickness of the coating film to be formed, the polymer concentration in the liquid crystal alignment agent can be appropriately changed. Based on the viewpoint of forming a uniform and defect-free coating film, the polymer concentration in the liquid crystal alignment agent is preferably 1wt% or more. Based on the viewpoint of the storage stability of the solution, the polymer concentration in the liquid crystal alignment agent is preferably 10wt% or less. The ideal polymer concentration can be 2wt% to 8wt%. The content of polymer (A) in the liquid crystal alignment agent 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 it can preferably be 2wt% to 10wt%, and more preferably 3wt% to 7wt%.

[0143] There is no particular limitation on the organic solvent contained in the liquid crystal alignment agent, as long as it can uniformly dissolve the aforementioned polymer. Specific examples include, but are not limited to, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, v-butyrolactone, gamma-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, or N-cyclohexyl-2-pyrrolidone, etc., and the aforementioned organic solvents are also referred to as good solvents. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, or γ-butyrolactone are preferred. Based on 100 wt % of the total amount of the solvent in the liquid crystal alignment agent, the amount of the good solvent may be 20 wt % to 99 wt %, preferably 20 wt % to 90 wt %, and more preferably 30 wt % to 80 wt %.

[0144] Secondly, the organic solvent in the liquid crystal alignment agent is preferably a mixed solvent of the aforementioned solvent and a solvent (also referred to as a poor solvent) that can improve the coating properties of the liquid crystal alignment agent and the surface smoothness of the coating film. The specific poor solvent used in combination can be, for example, but not limited to, the solvent described below. Based on the total amount of solvents used in the liquid crystal alignment agent being 100wt%, the amount of the poor solvent used is preferably 1wt% to 80wt%, more preferably 10wt% to 80wt%, and particularly preferably 20wt% to 70wt%. The type and amount of the poor solvent used can be appropriately selected based on the coating device, coating conditions and / or coating environment of the liquid crystal alignment agent.

[0145] For example, the poor solvent may be diisopropyl ether, diisobutyl ether, diisobutyl carbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene glycol monobutyl ether (butyl cellulose), ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy) )-2-propanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol 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.

[0146] Among them, diisobutyl carbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, or diisobutyl ketone is preferred.

[0147] The solvent combination of good solvent and poor solvent can be preferably, 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-dimethyl lactamide and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone and ethyl Glycol monobutyl ether acetate; N. ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether; N,N-dimethyl lactamide and ethylene glycol monobutyl ether; N,N-dimethyl lactamide and propylene glycol diacetate; N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether; N,N-dimethyl lactamide and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone and 4. hydroxy-4-methyl-2-pentanone; N. ethyl-2. pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; 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 and propylene glycol diacetate. Glycol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, v-butyrolactone, propylene glycol monobutyl ether and diisobutyl carbinol; N-methyl-2-pyrrolidone, gamma-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, v-butyrolactone and diisobutyl ketone; or N-ethyl-2-pyrrolidone, N,N-dimethyllactamide and diisobutyl ketone, etc.

[0148] The aforementioned solvent (C) may be used alone or in combination of two or more.

[0149] Based on 100 parts by weight of the total amount of polymer (A) and polymer (B), the amount of solvent (C) used is 800 to 4000 parts by weight, preferably 900 to 3500 parts by weight, and more preferably 1000 to 3000 parts by weight.

[0150] Additive ingredients

[0151] The liquid crystal alignment agent of the present invention may also optionally contain components other than the polymer component and the organic solvent (hereinafter referred to as additive components). These additive components may include, but are 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, compounds for increasing the strength of the liquid crystal alignment film (hereinafter referred to as cross-linking compounds), compounds for promoting imidization, and dielectrics or conductive substances for adjusting the dielectric constant or resistance of the liquid crystal alignment film.

[0152] Sealing agent

[0153] The aforementioned adhesion promoter may be, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, vinyltrimethoxysilane, Silane coupling agents include silane, vinyl triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris(3-trimethoxysilylpropyl)isocyanurate, and 3-isocyanatepropyltriethoxysilane. When using a bonding aid, based on the viewpoint of exhibiting good resistance to AC ghosting, the amount of the bonding aid used is preferably 0.1 to 30 parts by weight, and more preferably 0.1 to 20 parts by weight, relative to 100 parts by weight of the total amount of polymer used in the liquid crystal alignment agent.

[0154] Cross-linking compounds

[0155] The cross-linking compound described above may be a compound having an ethylene oxide group, a propylene oxide group, at least one group selected from the group consisting of a group represented by the following formula (E1) and a group represented by the following formula (E2), or a compound selected from the compound represented by the following formula (E3), in order to exhibit good resistance to AC image sticking and effectively improve film strength.

[0156]

[0157] In formula (E1), G1 and G2 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or -CH2-OH. In formula (E2), G3 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. G4 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), G5 represents a (g1+g2)-valent organic group containing an aromatic ring. G6 represents 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.

[0158] In formula (E3), the (g1+g2)-valent organic group having an aromatic ring represented by G5 can be a (g1+g2)-valent aromatic hydrocarbon group having 6 to 30 carbon atoms, a (g1+g2)-valent organic group formed by directly or through a linking group bonding an aromatic hydrocarbon group having 6 to 30 carbon atoms, or a (g1+g2)-valent group having an aromatic heterocycle. The aromatic hydrocarbon can be, for example, benzene or naphthalene. The aromatic heterocycle can be exemplified by the aromatic heterocycles exemplified in the above-mentioned specific nitrogen-containing atom structure. The linking group can be an alkylene group having 1 to 10 carbon atoms or a group obtained by removing a hydrogen atom from the alkylene group, or a divalent or trivalent cyclohexane group. Any hydrogen atom of the alkylene group can also be substituted with an organic group such as a fluorine atom or a trifluoromethyl group. In formula (E3), the alkyl group having 1 to 5 carbon atoms represented by G6 may be methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl or n-pentyl.

[0159] Compounds with ethylene oxide

[0160] Specific examples of the compound having an oxirane group include N,N,N′,N′-tetraepoxypropyl-m-xylenediamine, 1,3-bis(N,N-diepoxypropylaminomethyl)cyclohexane, N,N,N′,N′-tetraepoxypropyl-4,4′-diaminodiphenylmethane, N,N,N′,N′-tetraepoxypropyl-p-phenylenediamine, and nitrogen-containing compounds such as those represented by the following formulas (E4) to (E6):

[0161]

[0162]

[0163] Compounds having propylene oxide groups

[0164] Specific examples of the compound having an propylene oxide group include compounds represented by the following formulas (E7) to (E16):

[0165]

[0166]

[0167]

[0168] In formula (E15), R represents The “*” represents the bonding position.

[0169] Compounds having a group represented by formula (E1)

[0170] Specific examples of the compound having a group represented by formula (E1) include compounds represented by the following formulas (E1-1) to (E1-12):

[0171]

[0172]

[0173]

[0174] Compounds having a group represented by formula (E2)

[0175] Specific examples of the compound having a group represented by formula (E2) include compounds represented by the following formulas (E2-1) to (E2-4):

[0176]

[0177] Compounds having a group represented by formula (E3)

[0178] Specific examples of the compound having a group represented by formula (E3) include compounds represented by the following formulas (E3-1) to (E3-10):

[0179]

[0180]

[0181] In the liquid crystal alignment agent of the present invention, the amount of the crosslinking compound used is preferably 0.5 to 20 parts by weight based on 100 parts by weight of the total polymer used in the liquid crystal alignment agent. To ensure the crosslinking reaction and exhibit good resistance to AC image sticking, the amount of the crosslinking compound used is more preferably 1 to 15 parts by weight.

[0182] Compounds that promote imidization

[0183] The aforementioned compound for promoting imidization is preferably a compound having a basic site (for example, a primary amine 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 above-mentioned cross-linking compound and adhesion promoter), or a compound that produces the above-mentioned basic site upon calcination. More preferably, the compound that promotes imidization is a compound that produces the above-mentioned basic site upon calcination, and a specific example thereof can be, for example, an amino acid in which part or all of the basic sites possessed by an amino acid are protected. Specific examples of the above-mentioned amino acids can include glycine, alanine, cysteine, methionine, asparagine, glutamine, valine, leucine, phenylalanine, tyrosine, tryptophan, proline, hydroxyproline, arginine, histidine, lysine, or ornithine. Based on the purpose of the compound promoting imidization, a more preferred specific example can be N-α-(9-fluorenylmethoxycarbonyl)-N-τ-(tert-butyloxycarbonyl)-L-histidine.

[0184] Liquid crystal alignment film and method for manufacturing liquid crystal display component

[0185] The liquid crystal alignment film of the present invention is obtained from the aforementioned liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used as a horizontal alignment type or vertical alignment type (VA type) liquid crystal alignment film, and is suitable for a liquid crystal alignment film of a horizontal alignment type liquid crystal display device such as an IPS mode or a FFS mode. The liquid crystal display device of the present invention comprises the aforementioned liquid crystal alignment film. The liquid crystal display device of the present invention can be produced, for example, by the following steps (1) to (4) or steps (1) to (2) and step (4).

[0186] Step (1): Apply the liquid crystal alignment agent on the substrate

[0187] The liquid crystal alignment agent of the present invention is applied to one side of a substrate having a patterned transparent conductive film using an appropriate coating method such as roller coating, spin coating, printing, or inkjet coating. The substrate is not particularly limited; it only needs to be a highly transparent substrate. A glass substrate or silicon nitride substrate may also be used in combination with a plastic substrate such as an acrylic substrate or a polycarbonate substrate. Furthermore, in a reflective liquid crystal display device, if only one side of the substrate is used, an opaque material such as a silicon wafer may be used, and the electrodes used may be made of a light-reflecting material such as aluminum. Furthermore, when manufacturing an IPS or FFS liquid crystal device, a comb-tooth type device uses an electrode substrate having a patterned transparent conductive film or metal film and an opposing substrate having no electrodes.

[0188] Examples of methods for coating the liquid crystal alignment agent on a substrate to form a film include screen printing, offset printing, flexographic printing, inkjet printing, and spray coating, among which inkjet coating is preferred.

[0189] Step (2): calcining the coated liquid crystal alignment agent

[0190] Step (2) is a step of calcining the liquid crystal alignment agent coated on the substrate to form a film. After the liquid crystal alignment agent is coated on the substrate, the solvent can be evaporated by heating means such as a hot plate, a heat circulation oven or an IR (infrared) oven, or thermal imidization of polyamic acid or polyamic acid ester can be performed. The drying and calcining steps performed after the liquid crystal alignment agent of the present invention has been coated can be selected at any temperature and time, and multiple drying or calcining steps can be performed. The drying temperature can be, for example, 40°C to 180°C. Based on the viewpoint of shortening the process, it can be carried out at 40°C to 150°C. The drying time 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 aforementioned 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 time is not particularly limited, and may be 5 to 40 minutes or 5 to 30 minutes. If the film after calcination is too thin, the reliability of the liquid crystal display device will be reduced. Therefore, the film thickness is preferably 5 nm to 300 nm, and more preferably 10 nm to 200 nm.

[0191] Step (3): Alignment treatment of the film obtained in step (2)

[0192] Step (3) is to perform an alignment treatment on the film obtained in step (2) as appropriate. In other words, in a horizontal alignment type liquid crystal display component such as the IPS mode or the FFS mode, the coating film is subjected to an alignment treatment to impart alignment capability. On the other hand, in a vertical alignment type liquid crystal display component such as the VA mode or the PSA mode, the formed coating film can be used directly as a liquid crystal alignment film, but the coating film can also be subjected to an alignment treatment to impart alignment capability. The alignment treatment of the liquid crystal alignment film can include a friction treatment method or a light alignment treatment method, preferably a light alignment treatment method. The light alignment treatment method can include irradiating the surface of the above-mentioned film-like object with radiation that has been deflected in a certain direction, and, as appropriate, preferably heating at a temperature of 150°C to 250°C to impart liquid crystal alignment (also referred to as liquid crystal alignment capability). The radiation can use ultraviolet rays or visible light with a wavelength of 100nm to 800nm. Among them, the radiation is preferably ultraviolet light having a wavelength of 100 nm to 400 nm, and more preferably ultraviolet light having a wavelength of 200 nm to 400 nm.

[0193] The radiation dose can be 1mJ / cm 2Up to 10,000mJ / cm 2 , preferably 100mJ / cm 2 Up to 5,000mJ / cm 2 , more preferably 100mJ / cm 2 Up to 1500mJ / cm 2 , and preferably 100mJ / cm 2 Up to 1000mJ / cm 2 When using a general liquid crystal alignment agent, the light exposure for alignment treatment is 100mJ / cm 2 Up to 5000mJ / cm 2 , but the liquid crystal alignment agent of the present invention can still obtain a liquid crystal alignment film in which the variation (non-uniformity) of the liquid crystal alignment within the film surface is effectively suppressed even if the amount of light exposure during the alignment treatment is reduced. When irradiating with radiation, in order to improve the liquid crystal alignment, the substrate of the aforementioned film-like object can be heated at 50°C to 250°C while irradiating. The liquid crystal alignment film produced in this way can stably align the liquid crystal molecules in a certain direction. Secondly, the liquid crystal alignment film that has been irradiated with polarized radiation in the aforementioned method can be contact-treated with a solvent, or the liquid crystal alignment film that has been irradiated with radiation can be subjected to a heat treatment.

[0194] The solvent used in the aforementioned contact treatment is not particularly limited; it only needs to be able to dissolve the decomposition products generated from the film after irradiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl celecoxib, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, or cyclohexyl acetate. Among these, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred for their versatility and safety, and water, 1-methoxy-2-propanol, or ethyl lactate are more preferred. These solvents may be used alone or in combination.

[0195] The temperature for heat treatment of the radiation-irradiated coating film is preferably 50° C. to 300° C., and more preferably 120° C. to 250° C. The time for heat treatment is preferably 1 minute to 30 minutes.

[0196] Step (4): Making liquid crystal cells

[0197] Two substrates with the liquid crystal alignment films formed above are prepared, and liquid crystal is placed between the two facing substrates. For example, the following two methods can be used. The first method involves first placing the two substrates face-to-face with the liquid crystal alignment films facing each other, with a gap (cell gap) separating them. The two substrates are then bonded together with a sealant around their perimeters. The liquid crystal composition is then injected into the cell gap defined by the substrate surfaces and the sealant. Once the liquid crystal composition contacts the film surfaces, the injection hole is sealed.

[0198] The second method is called ODF (One Drop Fill). A sealant such as a UV-curable sealant is applied to a predetermined position on one of the two substrates on which a liquid crystal alignment film has been formed, and a liquid crystal composition is then added to a plurality of predetermined positions on the surface of the liquid crystal alignment film. Then, the other substrate is attached so that the liquid crystal alignment films face each other, and the liquid crystal composition is pushed onto the entire surface of the substrate so that it contacts the film surface. Next, ultraviolet light is irradiated onto the entire surface of the substrate to harden the sealant. When any of the aforementioned methods is performed, it is preferred to further heat the liquid crystal composition used to a temperature at which it becomes an isotropic phase, and then slowly cool it to room temperature to remove the flow alignment during liquid crystal filling. Secondly, when the coating film is subjected to a friction treatment, the two substrates are arranged so that the friction directions of the coating films are at a predetermined angle to each other, for example, in a perpendicular or antiparallel manner. The sealant may be, for example, an epoxy resin containing a hardener and aluminum oxide balls as spacers. Examples of the liquid crystal composition include nematic liquid crystals and smectic liquid crystals, and nematic liquid crystals are preferred.

[0199] Optionally, a polarizing plate can be attached to the outer surface of the liquid crystal cell to form a liquid crystal display device. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include a polarizing film made of elongated polyvinyl alcohol that also absorbs iodine, known as an "H-film." These can be formed by sandwiching a cellulose acetate protective film or by simply forming the H-film itself.

[0200] The following examples are used to illustrate the application of the present invention, but they are not intended to limit the present invention. Anyone skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. DETAILED DESCRIPTION

[0201] Preparation of polymer (A)

[0202] Synthesis Example A-1

[0203] A 500 ml four-necked Erlenmeyer flask was equipped with a nitrogen inlet, a stirrer, a condenser, and a thermometer, and nitrogen was introduced. Then, 0.824 g (0.0025 mol) of diamine compound (a2-1), 8.0 g (0.025 mol) of diamine compound (a2-2-1), 5.05 g (0.0175 mol) of diamine compound (a2-2-4), 1.00 g (0.005 mol) of 4,4-diaminodiphenyl ether (i.e., diamine compound (a2-3-2)), and 80 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) were added and stirred at room temperature until dissolved. Next, 3.36 g (0.015 mol) of compound (a1-1-1), 7.56 g (0.035 mol) of compound (a1-2-1), and 20 g of NMP were added, and the mixture was allowed to react at room temperature for 2 hours. After the reaction, the reaction solution was poured into 1500 ml of water to precipitate the polymer. The resulting polymer was filtered and the washing and filtering steps were repeated three times with methanol. The product was then placed in a vacuum oven and dried at 60°C to obtain the polymer (A-1) of Synthesis Example A-1. The formula is shown in Table 1.

[0204] Synthesis Examples A-2 to A-6 and Comparative Synthesis Examples A'-1 to A'-2

[0205] Synthesis Examples A-2 to A-6 and Comparative Synthesis Examples A'-1 to A'-2 use the same preparation method as the preparation method of the polymer (A-1) of Synthesis Example A-1, except that the types and amounts of raw materials in the polymers are changed in Synthesis Examples A-2 to A-6 and Comparative Synthesis Examples A'-1 to A'-2. The formulas are shown in Table 1 and are not further described here.

[0206] Preparation of polymer (B)

[0207] Synthesis Examples B-1 to B-4 and Comparative Synthesis Examples B'-1 to B'-2

[0208] Synthesis Examples B-1 to B-4 and Comparative Synthesis Examples B'-1 to B'-2 were prepared using the same method as the polymer (A-1) of Synthesis Example A-1, except that the types and amounts of raw materials used in the polymers were varied. Their formulations are shown in Table 2 and are not further detailed here.

[0209] Preparation of liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display component

[0210] Example 1

[0211] 50 parts by weight of the polymer (A-4) prepared in Synthesis Example A-4, 50 parts by weight of the polymer (B-4) prepared in Synthesis Example B-4, and 800 parts by weight of NMP were weighed and stirred at room temperature to prepare the liquid crystal alignment agent of Example 1.

[0212] The prepared liquid crystal alignment agent was spin-coated onto a glass substrate, on which a pixel electrode was formed. These IPS driving electrodes consisted of a pair of ITO electrodes (10 μm in width, 10 μm in spacing, and 50 nm in height). The ITO electrodes each had a comb-like shape, with the comb-like portions spaced and interlocking. The glass substrate coated with the liquid crystal alignment agent was then dried on an 80°C hotplate for 3 minutes and then baked in a 250°C hot air circulation oven for 30 minutes to form a 100 nm thick coating.

[0213] The coated surface was irradiated with 254nm ultraviolet light through a polarizing plate and then baked in a hot air circulating oven at 250°C for 30 minutes to produce a substrate with a liquid crystal alignment film. Similarly, a coating was formed and then aligned on a counter substrate, a glass substrate without electrodes but with 4μm-high columnar spacers.

[0214] The two substrates were assembled into a set. A sealant was printed on one of the substrates, and the other substrate was bonded together with the liquid crystal alignment film facing each other and aligned at 0°. The sealant was then cured to produce an empty cell. This empty cell was then injected with liquid crystal MLC-2041 (Merck) using a reduced-pressure injection method, and the injection port was sealed to produce the liquid crystal display device of Example 1. The resulting liquid crystal display device was evaluated using the following evaluation method, with the results shown in Table 3. The method for measuring flicker after high-voltage driving is described later.

[0215] Examples 2 to 12 and Comparative Examples 1 to 4

[0216] Examples 2 to 12 and Comparative Examples 1 to 4 use the same preparation method for the liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display component as Example 1. The difference is that Examples 2 to 12 and Comparative Examples 1 to 4 change the type and usage of the raw materials in the liquid crystal alignment agent. The formulas and evaluation results are shown in Tables 3 and 4, respectively, and are not further described here.

[0217] Table 1

[0218]

[0219]

[0220] Table 2

[0221]

[0222]

[0223] Table 3

[0224]

[0225] Table 4

[0226]

[0227] Evaluation method

[0228] Flicker after high voltage driving

[0229] The resulting LCD was placed between two polarizers with their polarization axes perpendicular to each other. The LED backlight was illuminated with no voltage applied, and the LCD's configuration angle was adjusted to minimize the brightness of the transmitted light. Next, an AC voltage with a frequency of 30 Hz was applied to the LCD, and the VT curve (voltage-transmittance curve) was measured. The AC voltages at which relative transmittances reached 23% and 100% were calculated as the driving voltages.

[0230] The method for measuring the flicker after driving is to turn off the lit LED backlight under the temperature condition of the liquid crystal display component at a temperature of 23°C, place it in a dark place for 72 hours, and then light it again. At the same time as the backlight starts to light up, an AC voltage with a relative transmittance of 100% and a frequency of 30Hz is applied. The drive is carried out for 24 hours, and then an AC voltage with a relative transmittance of 23% and a frequency of 30Hz is applied, and the amplitude of the flicker is tracked. The amplitude of the flicker is read using a data acquisition / data recording switching device 34970A (made by Agilent technologies) connected to a photodiode and an IV conversion amplifier, and the brightness value of the liquid crystal display component between the two polarizing plates is read. The flicker (FL) is calculated using the following formula (i):

[0231]

[0232] The lower the flicker, the better the quality of the liquid crystal display component made with the liquid crystal alignment agent.

[0233] In the above formula (i), z is the brightness value read when the device 34970A is driven by an AC voltage at a frequency of 30 Hz with a relative transmittance of 23%.

[0234] ※: FL<3%.

[0235] ◎: 3%≤FL<3.5%.

[0236] ○: 3.5%≤FL<4%.

[0237] △: 4%≤FL<5%.

[0238] ×: FL≥5%.

[0239] The results in Tables 3 and 4 indicate that when the diamine component (b2) used to react to form polymer (B) does not include the diamine compound (b2-1) represented by formula (B21), the liquid crystal display unit containing the resulting liquid crystal alignment film exhibits excessive flicker after high-voltage driving. Furthermore, when the diamine component (a2) used to react to form polymer (A) does not include the diamine compound (a2-1) represented by formula (A21), the liquid crystal display unit containing the resulting liquid crystal alignment film exhibits excessive flicker after high-voltage driving.

[0240] In addition, if the tetracarboxylic dianhydride component (a1) used to react to form polymer (A) comprises a structure represented by formula (I-1-1) (i.e., comprises tetracarboxylic dianhydride compound (a1-1-1)), the flicker of the resulting liquid crystal display unit after high-voltage driving can be further reduced. When the tetracarboxylic dianhydride component (b1) used to react to form polymer (B) comprises a structure represented by formula (III) (e.g., tetracarboxylic dianhydride compounds (b1-1-1) to (b1-1-3)), the flicker of the resulting liquid crystal display unit after high-voltage driving can be further reduced. Furthermore, when the diamine component (b2) used to react to form polymer (B) comprises a diamine compound having at least one nitrogen-containing structure selected from the group consisting of a nitrogen-containing heterocycle, a secondary amine group, and a tertiary amine group (e.g., diamine compounds (b2-2-1) to (b2-2-4)), the flicker of the resulting liquid crystal display unit after high-voltage driving can be further reduced.

[0241] It should be added that although the present invention uses specific compounds, compositions, reaction conditions, processes, analytical methods or specific instruments as examples to illustrate the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display component used in the photo-alignment method of the present invention, anyone with common knowledge in the technical field to which the present invention belongs can know that the present invention is not limited to this. Without departing from the spirit and scope of the present invention, the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display component used in the photo-alignment method of the present invention can also use other compounds, compositions, reaction conditions, processes, analytical methods or instruments.

[0242] Although the present invention has been disclosed above in terms of embodiments, this is not intended to limit the present invention. Anyone with common knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined by the appended claims.

Claims

1. A liquid crystal alignment agent for a photo-alignment method, characterized in that: Include: A polymer (A) is at least one polymer selected from the group consisting of a polyimide precursor and an imidized polymer of the polyimide precursor, wherein the polyimide precursor of the polymer (A) comprises a structure represented by the following formula (I): In formula (I), X1 is at least one selected from the group consisting of the structures represented by the following formulae (I-1) to (I-7), wherein "*" represents a bonding position; X2 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; In formula (I-1), X 11 、X 12 、X 13 With X 14 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group; and In formula (I-7), X 15 With X 16 Each independently represents a hydrogen atom or a methyl group; a polymer (B) selected from the group consisting of a polyimide precursor and an imidized polymer of the polyimide precursor, wherein the polyimide precursor of the polymer (B) comprises a structure represented by the following formula (II): In the formula (II), X3 represents a tetravalent organic group; X4 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and A solvent (C).

2. The liquid crystal alignment agent for photo-alignment method according to claim 1, characterized in that: The polymer (A) is obtained by reacting a tetracarboxylic dianhydride component (a1) and a diamine component (a2), and the diamine component (a2) comprises a compound represented by the following formula (A21):

3. The liquid crystal alignment agent for photo-alignment method according to claim 1, characterized in that: The polymer (B) is obtained by reacting a tetracarboxylic dianhydride component (b1) and a diamine component (b2), and the diamine component (b2) comprises a compound represented by the following formula (B21):

4. The liquid crystal alignment agent for photo-alignment method according to claim 1, characterized in that: X1 represents the structures shown in the following formulas (I-1-1) to (I-1-6):

5. The liquid crystal alignment agent for photo-alignment method according to claim 4, characterized in that: X1 represents a structure represented by formula (I-1-1).

6. The liquid crystal alignment agent for photo-alignment method according to claim 1, characterized in that: The polymer (B) is obtained by reacting a tetracarboxylic dianhydride component (b1) and a diamine component (b2), and the tetracarboxylic dianhydride component (b1) comprises a structure represented by the following formula (III): In the formula (III), Z 11 represents a single bond; and “*” represents the bonding position.

7. The liquid crystal alignment agent for photo-alignment method according to claim 1, characterized in that: The polyimide precursor of the polymer (B) is obtained by reacting a tetracarboxylic dianhydride component (b1) and a diamine component (b2), wherein the diamine component (b2) comprises a diamine compound having at least one nitrogen-containing structure selected from the group consisting of a nitrogen-containing heterocycle, a secondary amine group, and a tertiary amine group.

8. A liquid crystal alignment film, characterized in that: The liquid crystal alignment agent for photo-alignment method according to any one of claims 1 to 7 is used.

9. A liquid crystal display component, characterized in that: It comprises the liquid crystal alignment film as claimed in claim 8.

Images