Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element using the same

Abstract

To provide a liquid crystal aligning agent which enables production of a liquid crystal alignment film that offers good alignability and good adhesion to a sealant.SOLUTION: A liquid crystal aligning agent is provided, containing a polymer (A) having a repeating unit represented by formula (3), and a repeating unit represented by specific formula (5).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display device using the same.

Background Art

[0002] Conventionally, liquid crystal devices have been widely used as display units for personal computers, mobile phones, smartphones, television receivers, and the like. A liquid crystal device includes, for example, a liquid crystal layer sandwiched between an element 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 orientation of liquid crystal molecules in the liquid crystal layer, and a thin film transistor (TFT) for switching an electric signal supplied to the pixel electrodes. As driving methods for liquid crystal molecules, vertical electric field methods such as the TN method and the VA method, and horizontal electric field methods such as the IPS method and the FFS (fringe field switching) method are known.

[0003] Currently, the most industrially widespread liquid crystal alignment film is produced by performing a so-called rubbing treatment in which the surface of a film made of polyamic acid and / or polyimide obtained by imidizing the same formed on an electrode substrate is rubbed in one direction with a cloth such as cotton, nylon, or polyester. The rubbing treatment is a simple and industrially useful method with excellent productivity. However, with the high performance, high definition, and large size of liquid crystal display devices, various problems such as scratches on the surface of the alignment film generated by the rubbing treatment, dust generation, the influence of mechanical forces and static electricity, and further, non-uniformity within the alignment treatment surface have become apparent. As a liquid crystal alignment treatment method alternative to the rubbing treatment, an optical alignment method for imparting liquid crystal alignment ability by irradiating polarized radiation is known. Liquid crystal alignment treatments using an optical isomerization reaction, an optical crosslinking reaction, an optical decomposition reaction, etc. have been proposed (see Non-Patent Document 1 and Patent Document 1).

[0004] The liquid crystal alignment film, which is a component of a liquid crystal display device, is a film for uniformly aligning liquid crystals. However, not only the alignment uniformity of liquid crystals but also various properties are required. For example, charges accumulate in the liquid crystal alignment film due to the voltage for driving the liquid crystals, causing problems such as afterimages and image sticking (hereinafter referred to as afterimages derived from residual DC), which affect the display and significantly reduce the display quality of the liquid crystal display device. Therefore, liquid crystal alignment agents for overcoming these problems have been proposed (see Patent Document 2).

[0005] Also, in the IPS method and the FFS driving method, the stability of liquid crystal alignment is also important. If the stability of liquid crystal alignment is low, the liquid crystals will not return to the initial state when driven for a long time, causing a decrease in contrast and image sticking (hereinafter referred to as AC afterimages). As a method for solving the above problems, Patent Document 3 discloses a specific liquid crystal alignment agent.

[0006] Furthermore, with the spread of tablets and smartphones, the development of narrow-border liquid crystal display devices that secure the display area as wide as possible has been underway. Due to this narrowing of the border, it has become necessary to apply a sealant on the liquid crystal alignment film. Therefore, Patent Document 4 discloses a liquid crystal alignment agent that maintains good adhesion to the sealant while maintaining liquid crystal alignment properties.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Non-Patent Documents

[0008]

Non-Patent Document 1

[0009] Furthermore, the demand for higher resolution liquid crystal display elements is increasing, making it more important than ever to exhibit good display quality. The present invention has been made in view of the above circumstances, and its main objective is to provide a liquid crystal alignment film that has good liquid crystal alignment and good adhesion to a sealant, and a liquid crystal alignment agent that enables narrow bezels due to the good adhesion between the liquid crystal alignment film and the sealant, thereby enabling a liquid crystal display element that exhibits good display quality. [Means for solving the problem]

[0010] Through diligent research, the inventors discovered that the above problems could be solved by using a liquid crystal alignment agent containing a polymer component having specific repeating units, and thus completed the present invention. The present invention is summarized as follows: A liquid crystal alignment agent characterized by containing a polymer (A) having repeating units represented by the following formulas (1), (2), (3), and (4). [ka] (Each of R1 to R4 is independently a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 alkynyl group, a C1-C6 monovalent organic group containing a fluorine atom, or a phenyl group. They may be the same or different, but at least one of R1 to R4 represents a group other than a hydrogen atom as defined above. Y1 represents a divalent organic group having a substructure represented by the following formula (H).) [ka] (Q3 ha-(CH2) n The structure is represented by - (where n is an integer between 2 and 20), and any -CH2- may be replaced with a group selected from -O- and -C(=O)-, but oxygen atoms will never be directly bonded to each other. Any hydrogen atoms on the two benzene rings may be replaced with a monovalent organic group. (* represents a bond.) [ka] (X2 is a tetravalent organic group having an alicyclic structure with 5 or more members. Y2 represents a divalent organic group having the substructure represented by formula (H) above.) [ka] (R in equation (3)) 31 From R 34 These are equivalent to R1 to R4 in equation (1) above. X4 in equation (4) is equivalent to X2 in equation (2) above. Y3 and Y4 represent divalent organic groups represented by the following equation (I). [ka] (* indicates a bond.) [Effects of the Invention]

[0011] According to the liquid crystal alignment agent of the present invention, a liquid crystal alignment film is obtained that exhibits good liquid crystal alignment and good adhesion to a sealant, and a liquid crystal display element is obtained that exhibits good display quality because the adhesion between the liquid crystal alignment film and the sealant is good, and further narrowing of the bezel becomes possible. [Modes for carrying out the invention]

[0012] The following describes each component included in the liquid crystal alignment agent of the present invention, as well as other components that may be optionally added as needed. <Polymer (A)> The liquid crystal alignment agent of the present invention contains a polymer (A) having repeating units represented by formulas (1), (2), (3), and (4) above. With this configuration, a liquid crystal alignment film with less AC afterimage can be obtained, and a liquid crystal display element with excellent contrast can be obtained.

[0013] In equations (1) and (2) above, X2, Y1, Y2, R1, R2, R3, and R4 are as defined above.

[0014] Specific examples of C1-C6 alkyl groups in R1-R4 above include methyl, ethyl, propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, and n-pentyl groups. Specific examples of C2-C6 alkenyl groups in R1-R4 include vinyl, propenyl, and butynyl groups, which may be linear or branched. Specific examples of C2-C6 alkynyl groups in R1-R4 include ethynyl, 1-propynyl, and 2-propynyl groups. Halogen atoms in R1-R4 include fluorine, chlorine, bromine, and iodine atoms. Monovalent organic groups containing fluorine atoms, such as fluoromethyl and trifluoromethyl groups, are also included. From the viewpoint of high photoreactivity, R1 to R4 are hydrogen atoms or methyl groups, and it is preferable that at least one of R1 to R4 is a methyl group, and more preferably that at least two of R1 to R4 are methyl groups. Even more preferable is when R1 and R4 are methyl groups and R2 and R3 are hydrogen atoms.

[0015] Specific examples of monovalent organic groups that substitute for any hydrogen atom on the benzene ring in formula (H) above include halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and C1-C6 monovalent organic groups containing fluorine atoms, as exemplified by the structures shown in R1-R4 above. As for the substructure represented by the above formula (H), from the viewpoint of minimizing the generation of AC afterimages, any of the substructures represented by the following formulas (H-1) to (H-7) are recommended. [ka]

[0016] A preferred specific example of Y1 in formula (1) above is a divalent organic group represented by any of the following formulas (h-1) to (h-8), from the viewpoint of minimizing the generation of AC afterimages. [ka]

[0017] Polymer (A) has repeating units represented by the above formula (2) from the viewpoint of improving heat resistance. The tetravalent organic group X2 in formula (2) is preferably a tetravalent organic group having a 5- to 8-membered alicyclic structure, and more preferably a tetravalent organic group having a 5- to 7-membered alicyclic structure. A 5- or more-membered alicyclic structure means that, if the alicyclic structure to which the imide group is bonded is a polycyclic structure, then each ring in that polycyclic structure has 5 or more atoms constituting the ring. Furthermore, the above alicyclic structure only needs to be bonded to at least one of the two imide groups, and may also have a chain-like hydrocarbon structure or an aromatic ring structure.

[0018] A preferred example of X2 is a tetravalent organic group represented by any of the following formulas (X2-1) to (X2-12). [ka]

[0019] In equation (2), X2 is more preferably one of (X2-1) to (X2-4) from the viewpoint of reducing AC afterimage generation and improving the contrast of the liquid crystal display element. A preferred example of Y2 in equation (2) above is the same as a preferred example of Y1 in equation (1) above.

[0020] From the viewpoint of minimizing AC afterimages, polymer (A) preferably contains 1 to 95 mol%, more preferably 5 to 90 mol%, of the total repeating units represented by formula (1) and formula (2) relative to the total repeating units. Furthermore, the ratio ((1):(2)) of the repeating units represented by formula (1) to the repeating units represented by formula (2) in polymer (A) is preferably 70:30 to 99:1, more preferably 75:25 to 98:2, and even more preferably 80:20 to 97:3.

[0021] Polymer (A) has repeating units represented by formula (3) and formula (4) above, from the viewpoint of improving the contrast and seal adhesion of the liquid crystal display element. From the viewpoint of minimizing AC afterimages, polymer (A) preferably contains a total of 5 to 99 mol%, and more preferably 10 to 95 mol%, of the repeating units represented by formula (3) and formula (4) relative to the total repeating units. The ratio ((3):(4)) of the repeating units represented by formula (3) to the repeating units represented by formula (4) in polymer (A) is preferably 70:30 to 99:1, more preferably 75:25 to 98:2, and even more preferably 80:20 to 97:3.

[0022] The ratio ((1):(3)) of the repeating units represented by formula (1) to the repeating units represented by formula (3) in polymer (A) is preferably 1:99 to 99:1, more preferably 5:95 to 80:20, and even more preferably 10:90 to 70:30. The ratio ((2):(4)) of the repeating units represented by formula (2) to the repeating units represented by formula (4) in polymer (A) is preferably 1:99 to 99:1, more preferably 5:95 to 80:20, and even more preferably 10:90 to 70:30.

[0023] The polymer (A) preferably contains 6 to 100 mol%, particularly 15 to 100 mol% of the total of the repeating units represented by the above formulas (1), (2), (3) and (4) with respect to all the repeating units of the polymer (A).

[0024] From the viewpoint of further enhancing the adhesion to the sealing agent, the polymer (A) may have at least one repeating unit selected from the group consisting of the repeating unit represented by the following formula (5) and the repeating unit represented by the following formula (6).

Chemical formula

Chemical formula

[0025] In the above formulas (J-1) and (J-2), Q5 is a single bond, -(CH2) n -(n is an integer from 1 to 20), or -(CH2) n -where any -CH2- is replaced by -O-, -COO-, -OCO-, -NQ9-, -NQ9CO-, -CONQ9-, -NQ9CONQ 10 -, -NQ9COO-, or -OCOO- under the condition that they are not adjacent to each other. Q9 and Q 10 each independently represent a hydrogen atom or a monovalent organic group. Furthermore, Q6 and Q7 independently represent a group having -H, -NHD, -N(D)2, -NHD, or -N(D)2. Q8 represents a group having -NHD, -N(D)2, -NHD, or -N(D)2. D represents a carbamate protecting group, and examples of carbamate protecting groups include the tert-butoxycarbonyl group or the 9-fluorenylmethoxycarbonyl group. However, at least one of Q5, Q6, and Q7 has a carbamate protecting group in its group. *1 represents a bond.

[0026] Preferred specific examples of Y5 and Y6 include divalent organic groups represented by any of the following formulas (J-1-a) to (J-1-d) and (J-2-1), from the viewpoint of minimizing AC afterimages. Boc represents a tert-butoxycarbonyl group. [ka]

[0027] Polymer (A) may have, in addition to the repeating units represented by formulas (1) to (4) and the repeating units represented by formulas (5) and (6), at least one repeating unit selected from the group consisting of the repeating units represented by the following formulas (PI-A-1) and (PA-1). [ka]

[0028] In formula (PI-A-1), X I1 represents a tetravalent organic group, Y I1 represents a divalent organic group. However, X I1 If is a tetravalent organic group represented by the following formula (g) or is equivalent to X2 in the above formula (2), then Y I1 This represents a structure other than a divalent organic group having the substructure represented by formula (H), a divalent organic group represented by formula (I), a divalent organic group having the substructure represented by formula (J-1), or a divalent organic group represented by formula (J-2). I1Examples include the tetravalent organic group represented by the following formula (g), the tetravalent organic group exemplified by X2 in formula (2) above, and the following formula (X I1 -1)~(X I1 Examples include tetravalent organic groups represented by any of the following (-13), and tetravalent organic groups derived from aromatic tetracarboxylic dianhydrides. [ka] (R1, R2, R3, and R4 are equivalent to R1, R2, R3, and R4 in equation (1) above.)

[0029] [ka]

[0030] The above X 11 Aromatic tetracarboxylic dianhydrides that give a tetravalent organic group are acidic dianhydrides obtained by intramolecular dehydration of a carboxyl group attached to an aromatic ring such as a benzene ring or a naphthalene ring. Specific examples include tetravalent organic groups represented by any of the following formulas (X3-1) to (X3-2) and tetravalent organic groups represented by any of the following formulas (Xr-1) to (Xr-7). [ka] (x and y are independently a single bond, an ether (-O-), a carbonyl (-CO-), an ester (-COO-), an alkanediyl group with 1 to 5 carbon atoms, a 1,4-phenylene, a sulfonyl, or an amide group. j and k are 0 or 1. * represents a bond.) [ka]

[0031] In formula (PI-A-1), Y I1Specific examples of divalent organic groups include divalent organic groups having a substructure represented by formula (H) above, divalent organic groups represented by formula (I) above, divalent organic groups having a substructure represented by formula (J-1) above, divalent organic groups represented by formula (J-2) above, as well as divalent organic groups represented by any of the following formulas (o-1) to (o-23), and groups represented by any of the formulas (Y-1) to (Y-167) described in International Publication No. (WO) 2018 / 117239. [ka]

[0032] [ka]

[0033] [ka]

[0034] In formula (PA-1), X A1 represents a tetravalent organic group, Y A1 X represents a divalent organic group. A1 A concrete example of this is X in the above equation (PI-A-1). I1 The structure shown in the example is Y. A1 A concrete example of this is Y in the above equation (PI-A-1). I1 The structure exemplified above is one example.

[0035] In formula (PA-1), R A1 Z is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. A11 , Z A12 Each of these is independently a hydrogen atom, an optionally substituted C1-C10 alkyl group, an optionally substituted C2-C10 alkenyl group, an optionally substituted C2-C10 alkynyl group, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group.

[0036] The above R A1Specific examples of C1-C5 alkyl groups include methyl, ethyl, propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, and n-pentyl groups. From the viewpoint of ease of imidization by heating, R1 is preferably a hydrogen atom or a methyl group.

[0037] The above Z A11 , Z A12 Specific examples of alkyl groups having 1 to 10 carbon atoms include, in addition to the specific examples of alkyl groups having 1 to 5 carbon atoms exemplified in R1 above, hexyl group, heptyl group, octyl group, nonyl group, decyl group, etc. (See above Z) A11 , Z A12 Specific examples of alkenyl groups having 2 to 10 carbon atoms include vinyl groups, propenyl groups, and butynyl groups, which may be linear or branched. A11 , Z A12 Specific examples of alkynyl groups having 2 to 10 carbon atoms include the ethynyl group, 1-propynyl group, and 2-propynyl group. Z A11 , Z A12 The compound may have substituents, such as halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), hydroxyl groups, cyano groups, and alkoxy groups.

[0038] The ratio ((5):(6)) of the repeating unit represented by formula (5) to the repeating unit represented by formula (6) in polymer A is preferably 70:30 to 99:1, more preferably 75:25 to 98:2, and even more preferably 80:20 to 97:3.

[0039] The polymer (A) described above preferably has a total of 1 to 40 mol%, more preferably 1 to 30 mol%, and even more preferably 5 to 30 mol%, of the total repeating units represented by formula (5) and formula (6) relative to the total repeating units of polymer (A). In this case, the total amount of repeating units represented by formulas (1), (2), (3), and (4) is preferably 6 to 99 mol%, more preferably 15 to 99 mol%, and even more preferably 15 to 95 mol% relative to the total number of repeating units of polymer (A).

[0040] <Second Polymer> The liquid crystal alignment agent of the present invention is a composition containing the above polymer (A) and an organic solvent, and may contain two or more polymers (A) having different structures. Furthermore, the liquid crystal alignment agent of the present invention may contain polymers other than polymer (A) (hereinafter also referred to as a second polymer) and various additives. When the liquid crystal alignment agent of the present invention contains a second polymer, the content ratio of polymer (A) to the total polymer components is preferably 5% by mass or more, more preferably 5 to 95% by mass, and more preferably 10 to 90% by mass.

[0041] Examples of the second polymer include polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivative, and poly(meth)acrylate.

[0042] In particular, polyamic acid obtained from a tetracarboxylic dianhydride component and a diamine component (hereinafter also referred to as the second polyamic acid) is preferred as the second polymer.

[0043] Examples of tetracarboxylic dianhydride components for obtaining a second polyamic acid include compounds represented by the following formula (11). These tetracarboxylic dianhydride components may consist of two or more compounds. [ka] (A is a tetravalent organic group, preferably a tetravalent organic group having 4 to 30 carbon atoms.)

[0044] The following are examples of preferred A, but are not limited to these. [ka]

[0045] Of the above, (A-1) and (A-2) are preferred from the viewpoint of further improving photo-orientation, (A-4) is preferred from the viewpoint of further improving the relaxation rate of accumulated charge, and (A-15) to (A-17), etc., are preferred from the viewpoint of further improving liquid crystal orientation and the relaxation rate of accumulated charge.

[0046] The diamine component for obtaining the second polyamic acid can be appropriately determined depending on the purpose, but for example, a diamine represented by the following formula (12) can be used. [ka] (Y9 represents a divalent organic group. The two A9s are, independently, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms. From the viewpoint of liquid crystal orientation, A9 is preferably a hydrogen atom or a methyl group.)

[0047] For the purpose of improving electrical properties and relaxation properties, Y9 is preferably a divalent organic group having a secondary or tertiary nitrogen atom, or a divalent organic group having -NH-CO-NH- in the molecule. Specific examples of diamines represented by formula (12) when Y9 is a divalent organic group having a secondary or tertiary nitrogen atom include any of the diamines listed below (a) to (d).

[0048] (a) A diamine having a pyrrole structure as described in WO2017 / 126627, preferably a diamine having a structure represented by the following formula (pr). [ka] (R 1 The 'R' represents a hydrogen atom, fluorine atom, cyano group, hydroxyl group, or methyl group.2 Each of these is independently a single bond or group "*1-R 3 -Ph-*2 represents R 3 These are single bonds, -O-, -COO-, -OCO-, -(CH2) l -, -O(CH2) m This represents a divalent organic group selected from O-, -CONH-, and -NHCO-. l and m are integers from 1 to 5. *1 represents the site that bonds to the benzene ring in formula (pr), and *2 represents the site that bonds to the amino group in formula (pr). Ph represents the phenylene group. n is 1 to 3.

[0049] (b) A diamine having a pyrrole structure as described in WO2018 / 062197, preferably a diamine having a structure represented by the following formula (pn).

[0050] [ka] (R 1 and R 2 Each of these independently represents either a hydrogen atom or a methyl group. 3 This is a single bond or group "*1-R 4 -Ph-*2 represents R 4 These are single bonds, -O-, -COO-, -OCO-, -(CH2) l -, -O(CH2) m This represents a divalent organic group selected from O-, -CONH-, and -NHCO- (where l and m are integers from 1 to 5). *1 represents the site that bonds to the benzene ring in formula (pn), and *2 represents the site that bonds to the amino group in formula (pn). Ph represents the phenylene group. n represents 1 to 3.

[0051] (c) Diamines having a carbazole structure as described in WO2018 / 110354, preferably diamines having a structure represented by the following formula (cz). [ka] (R 1 R represents a hydrogen atom or a methyl group. 2 (This represents a methyl group.)

[0052] (d) Diamines having nitrogen-containing heterocycles as described in

[0173] to

[0188] of WO2015 / 046374, or diamines having nitrogen-containing structures as described in

[0050] of Japanese Patent Publication No. 2016-218149, or diamines represented by the following formula (BP), [ka] (X is a biphenyl ring or a fluorene ring. Y is a group selected from a benzene ring, a biphenyl ring, or -Ph-Z-Ph-, where Ph represents a phenylene group. Z is a divalent group represented by -O-, -NH-, -CH2-, -SO2-, -C(CH3)2-, or -C(CF3)2-. A and B are hydrogen atoms or methyl groups.) , 2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino-2,4-dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis(3-aminopropyl)piperazine, 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]dianiline, 2,4-diamino-6-isopropoxy-1,3,5-tri Azine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl-1,3,5-triazine, 2,4-diamino-1,3,5-triazine, 4,6-diamino-2-vinyl-1,3,5-triazine, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacrylidine lactate, 3,8-di Amino-6-phenylphenanthidine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis(4-aminophenyl)-N-phenylamine, 4,4'-diphenyl-N-methylamine, 4,4'-diaminodiphenylamine, 3,6-diaminocarbazole, 9-methyl-3,6-diaminocarbazole, 9-ethyl-3,6-diaminocarbazole, and diamines represented by the following formulas (w1) or (w2).

[0053] [ka] (Sp represents phenylene, pyrrolidine, piperidine, piperazine, a divalent chain hydrocarbon group having 2 to 20 carbon atoms, or a group in which the -CH2- of the divalent chain hydrocarbon group is substituted with a group selected from -O-, -CO-, -CO-O-, -NRCO- (where R represents a hydrogen atom or a methyl group), -NRCOO- (where R represents a hydrogen atom or a methyl group), -CONR- (where R represents a hydrogen atom or a methyl group), -COS-, -NR- (where R represents a methyl group), pyrrolidine, piperidine, and piperazine.)

[0054] Specific examples of diamines represented by formula (12) above when Y9 is a divalent organic group having -NH-CO-NH- in the molecule include diamines represented by the following formula (13) where A1 is -NH-CO-NH-, or a group in which at least one of the -CH2- of an alkylene group having 2 to 20 carbon atoms is substituted with -NH-CO-NH-, or a group in which at least one of the -CH2- of an alkylene group having 2 to 20 carbon atoms is substituted with -NH-CO-NH-, and at least one of the other -CH2- is substituted with a group selected from -O-, -CO-, -CO-O-, -NRCO- (R represents a hydrogen atom or a methyl group), -NRCOO- (R represents a hydrogen atom or a methyl group), -CONR- (R represents a hydrogen atom or a methyl group), -COS-, and -NR- (R represents a methyl group). A more preferred example of a diamine is a diamine represented by any of the following formulas (U-1) to (U-9).

[0055] [ka] (A1 represents a single bond, -NH-CO-NH-, or an alkylene group having 2 to 20 carbon atoms (however, any -CH2- of the alkylene group may be substituted with -O-, -CO-, -CO-O-, -NRCO- (R represents a hydrogen atom or a methyl group), -NRCOO- (R represents a hydrogen atom or a methyl group), -CONR- (R represents a hydrogen atom or a methyl group), -COS-, -NR- (R represents a methyl group), or -NH-CO-NH-). A2 represents a halogen atom, a hydroxyl group, or an alkyl or alkoxy group having 1 to 5 carbon atoms (any hydrogen atom of the alkyl or alkoxy group may be substituted with a halogen atom). a is an integer from 0 to 4, and if a is 2 or more, A2 may be the same or different. b and c are integers of 1 or 2.)

[0056] [ka]

[0057] Preferred specific examples of the diamine represented by the above formula (w1) or (w2) include the diamine represented by any of the following formulas (n3-1) to (n3-7), the diamine represented by any of the following formulas (n4-1) to (n4-6), and so on. [ka]

[0058] [ka]

[0059] For the purpose of improving printability, diamines having a carboxyl group (COOH group) or a hydroxyl group (OH group) can also be used. Specifically, examples include 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, or 3,5-diaminobenzoic acid. Among these, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, or 3,5-diaminobenzoic acid are preferred. In addition, diamines represented by the following formulas [3b-1] to [3b-4], or diamines in which these amino groups are secondary amino groups, can also be used.

[0060] [ka]

[0061] In formula [3b-1], Q 1 m 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-, 1 and m 2 Each of these independently represents an integer from 0 to 4, and m 1 +m 2 represents an integer from 1 to 4. In equation [3b-2], m 3 and m 4 Each of these independently represents an integer from 1 to 5. In equation [3b-3], Q 2 This represents a linear or branched alkylene group having 1 to 5 carbon atoms, m 5 represents an integer from 1 to 5. In equation [3b-4], Q 3 and Q 4Each of these 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-, and m 6 (This represents an integer between 1 and 4.)

[0062] As the diamine component for obtaining the second polyamic acid, in addition to the above, the diamine used to obtain polymer (A) or known diamines can be used. Two or more types of diamines may be used in combination as the diamine component for obtaining the second polyamic acid.

[0063] <Methods for producing polyamic acid, polyamic acid esters, and polyimides> The polyamic acid esters, polyamic acids, and polyimides used as polyimide precursors in the present invention can be produced by known methods, such as those described in WO2013 / 157586.

[0064] <Liquid crystal alignment agent> The liquid crystal alignment agent of the present invention may contain polymer (A) and optionally a second polymer, and furthermore, other polymers in addition to these. Examples of other polymers include polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivative, and poly(meth)acrylate.

[0065] Liquid crystal alignment agents are used to produce liquid crystal alignment films and, from the viewpoint of forming a uniform thin film, they take the form of a coating solution. In the liquid crystal alignment agent of the present invention, it is preferable that the coating solution contains the polymer component described above and an organic solvent. In this case, the concentration (content) of the polymer in the liquid crystal alignment agent can be appropriately changed depending on the desired thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, a concentration of 1% by mass or more is preferable, and from the viewpoint of the storage stability of the solution, 10% by mass or less is preferable. A particularly preferred polymer concentration is 2 to 8% by mass.

[0066] The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as it is a solvent (also called a good solvent) in which the polymer components dissolve uniformly. Specific examples include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropanamide, and 3-butoxy-N,N-dimethylpropanamide. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, or γ-butyrolactone are preferred. The good solvent is preferably 20 to 99% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass.

[0067] Furthermore, it is preferable to use a mixed solvent in which the organic solvent contained in the liquid crystal alignment agent is a good solvent in addition to a solvent (also called a poor solvent) that improves the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent. Specific examples of poor solvents are listed below, but the invention is not limited to these examples. For example, diisopropyl ether, diisobutyl ether, diisobutylcarbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy) Examples include -1-propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, 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, and diisobutyl ketone (2,6-dimethyl-4-heptanone).

[0068] Among the poor solvents, diisobutylcarbinol, 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, and diisobutyl ketone are preferred.

[0069] Preferred solvent combinations of good and poor solvents include: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, and N-methyl-2-pyrrolidone and γ-butyrolactone. Examples include propylene glycol monobutyl ether and 2,6-dimethyl-4-heptanone, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisopropyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and 2,6-dimethyl-4-heptanol, N-methyl-2-pyrrolidone and γ-butyrolactone and dipropylene glycol dimethyl ether, and N-methyl-2-pyrrolidone and propylene glycol monobutyl ether and dipropylene glycol dimethyl ether. These poor solvents are preferably present in amounts of 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. The type and content of such solvents are appropriately selected depending on the coating apparatus, coating conditions, and coating environment of the liquid crystal alignment agent.

[0070] The liquid crystal alignment agent of the present invention may additionally contain components other than polymer components and organic solvents. Examples of such additional components include adhesion aids to improve the adhesion between the liquid crystal alignment film and the substrate, and between the liquid crystal alignment film and the sealing material, compounds to increase the strength of the liquid crystal alignment film (hereinafter also referred to as crosslinking compounds), and dielectrics and conductive materials to adjust the dielectric constant and electrical resistance of the liquid crystal alignment film.

[0071] As the above crosslinkable compound, from the viewpoint of reducing the generation of AC afterimages and having a high effect in improving film strength, a compound having at least one group selected from the group consisting of an oxyranyl group, an oxetanyl group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a meldrum acid structure, a cyclocarbonate group, or a group represented by the following formula (d), or a compound represented by the following formula (e) (hereinafter, these are collectively referred to as compound (C)). [ka] (R 71 R is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH". 72 and R 73 Each of these is independently a hydrogen atom, a C1-C3 alkyl group, or "*-CH2-OH". * indicates a bond. A represents an (m+n) valence organic group with an aromatic ring. m represents an integer from 1 to 6, and n represents an integer from 0 to 4.

[0072] Specific examples of compounds having an oxiranil group include compounds having two or more oxiranil groups, such as the compound described in

[0037] of Japanese Patent Publication No. 10-338880 and the compound having a triazine ring as its backbone, as described in WO2017 / 170483. Of these, compounds containing nitrogen atoms, such as N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, and compounds represented by any of the following formulas (r-1) to (r-3), are particularly preferred. [ka]

[0073] Specific examples of compounds having an oxetanyl group include compounds having two or more oxetanyl groups as described in sections

[0170] to

[0175] of WO2011 / 132751.

[0074] Specific examples of compounds having protected isocyanate groups include compounds having two or more protected isocyanate groups as described in sections

[0046] to

[0047] of Japanese Patent Publication No. 2014-224978, and compounds having three or more protected isocyanate groups as described in sections

[0119] to

[0120] of WO2015 / 141598. Of these, compounds represented by any of the following formulas (bi-1) to (bi-3) are preferred. [ka]

[0075] Specific examples of compounds having protected isothiocyanate groups include the compound having two or more protected isothiocyanate groups described in Japanese Patent Publication No. 2016-200798. Specific examples of compounds having a group containing an oxazoline ring structure include the compound containing two or more oxazoline structures described in

[0115] of Japanese Patent Publication No. 2007-286597.

[0076] Specific examples of compounds having a group containing a meldrum acid structure include compounds having two or more meldrum acid structures, as described in WO2012 / 091088. Specific examples of compounds having a cyclocarbonate group include the compounds described in WO2011 / 155577. Examples of C1-C3 alkyl groups for R1, R2, and R3 of the group represented by formula (d) above include methyl, ethyl, and propyl groups.

[0077] Specific examples of compounds having the group represented by formula (d) above include compounds having two or more of the group represented by formula (d) above, as described in WO2015 / 072554 and Japanese Patent Publication No. 2016-118753

[0058] , and compounds described in Japanese Patent Publication No. 2016-200798. Of these, compounds represented by any of the following formulas (hd-1) to (hd-8) are preferred.

[0078] [ka]

[0079] Examples of (m+n) valence organic groups having an aromatic ring in A of formula (e) above include (m+n) valence aromatic hydrocarbon groups having 5 to 30 carbon atoms, (m+n) valence organic groups in which aromatic hydrocarbon groups having 5 to 30 carbon atoms are directly or via linking groups, and (m+n) valence groups having an aromatic heterocycle. Examples of the above aromatic hydrocarbon groups include benzene and naphthalene. Examples of aromatic heterocycles include pyrrole rings, imidazole rings, pyrazole rings, pyridine rings, pyrimidine rings, quinoline rings, isoquinoline rings, carbazole rings, pyridazine rings, pyrazine rings, benzimidazole rings, benzimidazole rings, indole rings, quinoxaline rings, and acridine rings. Examples of the above linking groups include alkylene groups having 1 to 10 carbon atoms, or groups obtained by removing one hydrogen atom from the above alkylene groups, and divalent or trivalent cyclohexane rings. Furthermore, any hydrogen atom of the alkylene group may be substituted with a fluorine atom or an organic group such as a trifluoromethyl group. Specific examples include the compounds described in WO2010 / 074269. Preferred specific examples include any of the following formulas (e-1) to (e-9).

[0080] [ka]

[0081] The above-mentioned compounds are examples of crosslinkable compounds and are not limited to these. For example, other components disclosed in sections

[0105] to

[0116] of WO2015 / 060357 may be included. Furthermore, two or more crosslinkable compounds may be combined in the liquid crystal alignment agent of the present invention. In the liquid crystal alignment agent of the present invention, the content of the crosslinkable compound is preferably 0.5 to 20 parts by mass per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, and more preferably 1 to 15 parts by mass from the viewpoint of ensuring that the crosslinking reaction proceeds, the desired effect is achieved, and AC afterimages are minimized.

[0082] Examples of the adhesion aids mentioned above include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, and N-trimethoxysilylpropyl Triethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonylacetate, 9-triethoxysilyl-3,6-diazanonylacetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxyethylene)-3-aminopropyltrimethoxysilane, N-bis(oxyethylene)-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,Examples of silane coupling agents include 4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatetopropyltriethoxysilane. From the viewpoint of minimizing the generation of AC afterimages, the amount of these silane coupling agents used is preferably 0.1 to 30 parts by mass, and more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

[0083] <Method for manufacturing liquid crystal alignment film> A liquid crystal alignment film using the liquid crystal alignment agent of the present invention can be manufactured using the liquid crystal alignment agent of the present invention by known methods for obtaining a liquid crystal alignment film from a liquid crystal alignment agent. In particular, a liquid crystal alignment film using the liquid crystal alignment agent of the present invention can be efficiently manufactured by sequentially performing the following steps (1), (2), (3), and preferably (4).

[0084] <Process (1)> This is a process of applying the liquid crystal alignment agent of the present invention onto a substrate. The substrate on which the liquid crystal alignment agent is applied is not particularly limited as long as it is a highly transparent substrate, and can be a glass substrate, a silicon nitride substrate, an acrylic substrate, a plastic substrate such as a polycarbonate substrate, etc. In this case, it is preferable to use a substrate on which ITO electrodes for driving the liquid crystal are formed, in order to simplify the process. Furthermore, in the case of a reflective liquid crystal display element, one side of the substrate can be an opaque material such as a silicon wafer, and in this case, a light-reflecting material such as aluminum can be used for the electrodes. Industrially, liquid crystal alignment agents are typically applied using methods such as screen printing, offset printing, flexographic printing, or inkjet printing. Other application methods include dip coating, roll coating, slit coating, spinner coating, or spray coating, which may be used depending on the purpose.

[0085] <Process (2)> Step (2) is a step of heating the liquid crystal alignment agent coating obtained in step (1). After coating the substrate with the liquid crystal alignment agent, the solvent can be evaporated or the amic acid or amic acid ester in the polymer can be thermally imidized using a heating means such as a hot plate, a heat-circulating oven, or an IR (infrared) oven. The drying and firing steps after coating the liquid crystal alignment agent can be performed at any temperature and for any duration, and may be performed multiple times. The temperature at which the organic solvent of the liquid crystal alignment agent is removed can be, for example, 40 to 150°C. From the viewpoint of shortening the process, it may also be performed at 40 to 120°C. The firing time is not particularly limited, but examples include 1 to 10 minutes or 1 to 5 minutes. When thermally imidizing the amic acid or amic acid ester in the polymer is performed, after the step of removing the organic solvent, firing can be performed at, for example, 190 to 250°C or 200 to 240°C. The firing time is not particularly limited, but examples include 5 to 40 minutes or 5 to 30 minutes.

[0086] <Process (3)> Step (3) is a step of irradiating the film obtained in step (2) with polarized ultraviolet light. The wavelength of the ultraviolet light is preferably 200 to 400 nm, and more preferably 200 to 300 nm. In order to improve the liquid crystal alignment, the substrate coated with the liquid crystal alignment film may be heated at 50 to 250°C while being irradiated with ultraviolet light. The irradiation dose of the above radiation is 1 to 10,000 mJ / cm². 2 Preferably, 100 to 5,000 mJ / cm² 2 This is more preferable. The liquid crystal alignment film fabricated in this way can stably align liquid crystal molecules in a specific direction. A higher extinction ratio for polarized ultraviolet light is preferable because it imparts greater anisotropy. Specifically, the extinction ratio for linearly polarized ultraviolet light is preferably 10:1 or higher, and more preferably 20:1 or higher.

[0087] <Process (4)> Step (4) is a step of firing the film obtained in step (3) at a temperature of 100°C or higher and higher than the temperature in step (2). The firing temperature is not particularly limited as long as it is 100°C or higher and higher than the firing temperature in step (2), but 150 to 300°C is preferred, 150 to 250°C is more preferred, and 200 to 250°C is even more preferred. The firing time is preferably 5 to 120 minutes, more preferably 5 to 60 minutes, and even more preferably 5 to 30 minutes. The thickness of the liquid crystal alignment film after firing is preferably 5 to 300 nm, and more preferably 10 to 200 nm, because if it is too thin, the reliability of the liquid crystal display element may decrease.

[0088] Furthermore, after performing either step (3) or (4) above, the obtained liquid crystal alignment film can be subjected to contact treatment using water and / or a solvent. The solvent used in the above contact treatment is not particularly limited, as long as it is a solvent that dissolves the decomposition products generated from the liquid crystal alignment film by ultraviolet irradiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, or cyclohexyl acetate. Among these, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred in terms of versatility and solvent safety. More preferably, water, 1-methoxy-2-propanol, or ethyl lactate are preferred. Two or more solvents may be used in combination.

[0089] The above-mentioned contact treatment, that is, the treatment of a liquid crystal alignment film irradiated with polarized ultraviolet light with water or a solvent, can be performed by immersion treatment or spray treatment (also called spray treatment). The treatment time in these treatments is preferably 10 seconds to 1 hour, in order to efficiently dissolve the decomposition products generated from the liquid crystal alignment film by ultraviolet light. In particular, immersion treatment for 1 to 30 minutes is preferred. The solvent used in the above-mentioned contact treatment may be at room temperature or heated, but is preferably 10 to 80°C. In particular, 20 to 50°C is preferred. In addition, ultrasonic treatment may be performed as needed in order to improve the solubility of the decomposition products.

[0090] After the above contact treatment, it is preferable to rinse (also called rinsing) with a low-boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone, or to perform firing of the liquid crystal alignment film. At that time, either rinsing or firing may be performed, or both may be performed. The firing temperature is preferably 150 to 300°C, more preferably 180 to 250°C, and more preferably 200 to 230°C. The firing time is preferably 10 seconds to 30 minutes, and more preferably 1 to 10 minutes.

[0091] The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for transverse electric field type liquid crystal display elements such as IPS type and FFS type, and is particularly useful as a liquid crystal alignment film for FFS type liquid crystal display elements. A liquid crystal display element is obtained by first obtaining a substrate with a liquid crystal alignment film obtained from a liquid crystal alignment agent, then fabricating a liquid crystal cell by a known method, and using the liquid crystal cell. As an example of a liquid crystal cell manufacturing method, we will explain using a liquid crystal display element with a passive matrix structure as an example. Alternatively, an active matrix liquid crystal display element may be used, in which switching elements such as TFTs (Thin Film Transistors) are provided in each pixel portion that constitutes the image display.

[0092] Specifically, a transparent glass substrate is prepared, and a common electrode is placed on one substrate and a segment electrode on the other. These electrodes can be, for example, ITO electrodes and are patterned to display a desired image. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film can be, for example, an SiO2-TiO2 film formed by the sol-gel method. Next, a liquid crystal alignment film is formed on each substrate, and the other substrate is placed on top of one substrate so that the liquid crystal alignment film surfaces of the two substrates face each other, and the edges are bonded together with a sealant. To control the gap between the substrates, spacers are usually mixed into the sealant, and it is preferable to also scatter spacers for substrate gap control in the in-plane areas where no sealant is applied. An opening is provided in a part of the sealant to allow liquid crystal to be filled from the outside. Then, the liquid crystal material is injected through the opening in the sealant into the space surrounded by the two substrates and the sealant, and the opening is then sealed with an adhesive. For injection, a vacuum injection method may be used, or a method utilizing capillary action in the atmosphere may be used. Either positive-type or negative-type liquid crystal material may be used. Next, polarizing plates are installed. Specifically, a pair of polarizing plates are attached to the sides of the two substrates opposite to the liquid crystal layers.

[0093] As described above, by using the manufacturing method of the present invention, afterimages caused by long-term AC driving that occur in IPS-driven and FFS-driven liquid crystal display elements can be suppressed. Furthermore, by removing the organic solvent at 40 to 150°C in step (2) and then carrying out step (3), a liquid crystal alignment film can be obtained with fewer steps than conventional methods. The liquid crystal alignment agent of the present invention can be particularly preferably used in a method for manufacturing a liquid crystal alignment film that includes the step of removing the organic solvent at 40 to 150°C in step (2) and then carrying out step (3).

[0094] As described above, by using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film can be obtained that exhibits less residual DC and AC afterimage generation and high seal adhesion. In particular, a liquid crystal display element with excellent contrast that suppresses variations in brightness within the plane when displaying black can be obtained, resulting in a liquid crystal display element with good display quality. [Examples]

[0095] The present invention will be further described with reference to the following examples, but the present invention is not limited to these. The abbreviations for the compounds and the methods for measuring each property below are as follows. (solvent) NMP: N-methyl-2-pyrrolidone, GBL: γ-butyrolactone BCS: Butyl cellosolve, (Diamine) DA-1 to DA-4: Compounds represented by the following formulas (DA-1) to (DA-4), respectively. (Tetracarboxylic acid dianhydride) CA-1 and CA-2: Compounds represented by the following formulas (CA-1) and (CA-2), respectively. (Additives) C-1: Compound represented by the following formula (C-1) C-2: 2,2'-Bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane S-1: Compound represented by the following formula (S-1),

[0096] [ka]

[0097] [ka]

[0098] [ka]

[0099] <Viscosity Measurement> A TVE-22H E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) was used, with a sample volume of 1.1 mL, and measurements were taken at 25°C using a TE-1 cone rotor (1°34', R24).

[0100] <Measurement of Imidification Rate> 20 mg of polyimide powder was placed in an NMR sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Science Co., Ltd.)), and 0.53 mL of deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) was added. The solution was then completely dissolved by sonication. The 500 MHz proton NMR of this solution was measured using an NMR analyzer (JNW-ECA500) (manufactured by JEOL Datum Corporation). The imidation rate was determined by using the following formula, with a reference proton derived from a structure that does not change before and after imidation, and the sum of the peak values ​​of this proton and the sum of the proton peaks derived from the NH group of the amide acid that appears around 9.5 ppm to 10.0 ppm. Imidization rate (%) = (1 - α·x / y) × 100 In the above formula, x is the integrated value of proton peaks derived from the NH group of the amide acid, y is the integrated value of the reference proton peaks, and α is the ratio of the number of reference protons to one NH group proton of the amide acid in the case of a polyamide acid (imidization rate of 0%).

[0101] [Examples of polymer synthesis] The following are examples of polyamic acid and polyimide synthesis. Note that PI indicates polyimide.

[0102] <Synthesis Example 1> In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 7.33 g (0.03 mol) of DA-1 was weighed out, and 99.1 g of NMP was added. The mixture was stirred while supplying nitrogen to dissolve the DA-1. While stirring this diamine solution, 6.19 g (0.028 mol) of CA-1 was added, and the mixture was stirred at 40°C for 24 hours to obtain polyamic acid solution (A-1) (viscosity: 107 mPa·s).

[0103] <Synthesis Example 2> In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 4.10 g (0.0168 mol) of DA-1 and 8.32 g (0.0392 mol) of DA-3 were weighed out, and 176 g of NMP was added. The mixture was stirred while supplying nitrogen to dissolve the compounds. While stirring this diamine solution, 11.6 g (0.0518 mol) of CA-1 was added, and the mixture was stirred at 40°C for 24 hours to obtain polyamic acid solution (A-2) (viscosity: 219 mPa·s).

[0104] <Synthesis Example 3> In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 6.37 g (0.03 mol) of DA-3 was weighed out, and 92.3 g of NMP was added. The mixture was stirred while supplying nitrogen to dissolve the DA-3. While stirring this diamine solution, 6.22 g (0.0278 mol) of CA-1 was added, and the mixture was stirred at 40°C for 24 hours to obtain polyamic acid solution (A-3) (viscosity: 347 mPa·s).

[0105] <Synthesis Example 4> In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 2.05 g (0.0084 mol) of DA-1 and 4.16 g (0.0196 mol) of DA-3 were weighed out, and 88.6 g of NMP was added. The mixture was stirred while supplying nitrogen to dissolve the compounds. While stirring this diamine solution, 5.52 g (0.0246 mol) of CA-1 and 0.35 g (0.0014 mol) of CA-2 were added, and the mixture was stirred at 40°C for 24 hours to obtain polyamic acid solution (A-4) (viscosity: 213 mPa·s).

[0106] <Synthesis Example 5> In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 3.23 g (0.0084 mol) of DA-2 and 4.16 g (0.0196 mol) of DA-3 were weighed out, and 97.3 g of NMP was added. The mixture was stirred while supplying nitrogen to dissolve the compounds. While stirring this diamine solution, 5.52 g (0.0246 mol) of CA-1 and 0.35 g (0.0014 mol) of CA-2 were added, and the mixture was stirred at 40°C for 24 hours to obtain polyamic acid solution (A-5) (viscosity: 198 mPa·s).

[0107] <Synthesis Example 6> In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 1.37 g (0.0056 mol) of DA-1, 4.16 g (0.0196 mol) of DA-3, and 1.56 g (0.0028 mol) of DA-4 were weighed out, and 95.1 g of NMP was added. The mixture was stirred while supplying nitrogen to dissolve the substances. While stirring this diamine solution, 5.52 g (0.0246 mol) of CA-1 and 0.35 g (0.0014 mol) of CA-2 were added, and the mixture was stirred at 40°C for 24 hours to obtain polyamic acid solution (A-6) (viscosity: 224 mPa·s).

[0108] <Synthesis Example 7> In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 1.37 g (0.0056 mol) of DA-1, 4.16 g (0.0196 mol) of DA-3, and 1.56 g (0.0028 mol) of DA-4 were weighed out, and 95.3 g of NMP was added. The mixture was stirred while supplying nitrogen to dissolve the substances. While stirring this diamine solution, 5.21 g (0.0232 mol) of CA-1 and 0.700 g (0.0028 mol) of CA-2 were added, and the mixture was stirred at 40°C for 24 hours to obtain polyamic acid solution (A-7) (viscosity: 177 mPa·s).

[0109] <Synthesis Example 8> In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 1.37 g (0.0056 mol) of DA-1, 4.16 g (0.0196 mol) of DA-3, and 1.56 g (0.0028 mol) of DA-4 were weighed out, and 95.6 g of NMP was added. The mixture was stirred while supplying nitrogen to dissolve the compounds. While stirring this diamine solution, 4.90 g (0.0218 mol) of CA-1 and 1.05 g (0.0042 mol) of CA-2 were added, and the mixture was stirred at 40°C for 24 hours to obtain polyamic acid solution (A-8) (viscosity: 176 mPa·s).

[0110] <Synthesis Example 9> 35 g (0.0093 mol) of the obtained polyamic acid solution (A-1) was placed in a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 11.7 g of NMP was added, and the mixture was stirred for 30 minutes. To the obtained polyamic acid solution, 2.84 g of acetic anhydride (3 equivalents relative to the molar amount of polyamic acid) and 0.73 g of pyridine (equivalent to the molar amount of polyamic acid) were added, and the mixture was heated at 50°C for 3 hours to perform chemical imidization. The resulting reaction solution was added to 150 ml of methanol while stirring, the precipitated material was filtered off, and the same procedure was repeated twice to wash the resin powder. After washing, the mixture was dried at 60°C for 12 hours to obtain polyimide resin powder. The imidization rate of this polyimide resin powder was 71%. 3.60 g of the obtained polyimide resin powder was placed in a 100 ml Erlenmeyer flask, 26.4 g of NMP was added to achieve a solid content concentration of 12%, and the mixture was stirred at 70°C for 24 hours to dissolve and obtain a polyimide solution (A-1-PI).

[0111] <Synthesis Examples 10-16> Except for using the raw materials listed in Table 1 below, the process was carried out similarly using the method of Synthesis Example 9. The specifications of the polyimides obtained in Synthesis Examples 10-16, along with those from Synthesis Example 9, are shown in Table 1. [Table 1]

[0112] In Table 1, the numbers in parentheses represent the proportion (moles) of each compound relative to 100 moles of the total amount of tetracarboxylic acid derivatives used in the synthesis for the tetracarboxylic acid components, and the proportion (moles) of each compound relative to 100 moles of the total amount of diamines used in the synthesis for the diamine components. For organic solvents, the numbers represent the proportion (parts by mass) of each organic solvent relative to 100 parts by mass of the total amount of organic solvents contained in the polyamic acid solution or polyimide solution.

[0113] [Preparation of liquid crystal alignment agent] <Comparative Example 1> In a 20 ml sample tube containing a stirring bar, 7.5 g of polyimide solution (A-1-PI) was weighed out, and 2.23 g of NMP, 5.10 g of GBL, 4.0 g of BCS, 0.90 g of GBL solution containing 1% by weight of S-1, and 0.27 g of NMP solution containing 10% by weight of C-1 were added. The mixture was then stirred with a magnetic stirrer for 30 minutes to obtain liquid crystal alignment agent (R1).

[0114] <Example 1> In a 20 ml sample tube containing a stirring bar, 7.5 g of polyimide solution (A-4-PI) was placed, and 2.23 g of NMP, 5.10 g of GBL, 4.0 g of BCS, 0.90 g of GBL solution containing 1% by weight of S-1, and 0.27 g of NMP solution containing 10% by weight of C-1 were added. The mixture was then stirred with a magnetic stirrer for 30 minutes to obtain liquid crystal alignment agent (1).

[0115] <Examples 2-6, Comparative Example 3> In Examples 2-6 and Comparative Example 3, the liquid crystal alignment agents were obtained in the same manner as in Comparative Example 1 and Example 1, except that the polyimide solutions, additives, and organic solvents listed in Table 2 below were used. The specifications of each obtained liquid crystal alignment agent, along with those of Example 1 and Comparative Example 1, are shown in Table 1.

[0116] [Table 2] The numbers in parentheses represent the proportion (mass %) of each component relative to 100 parts by mass of the total amount of liquid crystal alignment agent.

[0117] <Fabrication of liquid crystal display elements> A substrate with electrodes was prepared. The substrate is a glass substrate measuring 30 mm x 35 mm and with a thickness of 0.7 mm. On the substrate, an IZO electrode with a solid pattern is formed as the first layer, which constitutes the counter electrode. On top of the first layer counter electrode, a SiN (silicon nitride) film deposited by CVD is formed as the second layer. The thickness of the second SiN film is 500 nm and functions as an interlayer insulating film. On top of the second SiN film, a comb-shaped pixel electrode formed by patterning the IZO film is arranged as the third layer, forming two pixels, the first and second pixels. The size of each pixel is 10 mm vertically and approximately 5 mm horizontally. At this time, the first layer counter electrode and the third layer pixel electrode are electrically insulated by the action of the second layer SiN film.

[0118] The third layer of pixel electrodes has a comb-like shape, composed of multiple electrode elements with a central bend, forming a "V" shape. The width of each electrode element in the short direction is 3 μm, and the spacing between electrode elements is 6 μm. Because the pixel electrodes forming each pixel are composed of multiple electrode elements with a central bend, forming a "V" shape, the shape of each pixel is not rectangular, but rather has a shape similar to the bolded "V" shape, which is bent in the middle, just like the electrode elements. Each pixel is divided into upper and lower halves by its central bend, and has a first region above the bend and a second region below the bend.

[0119] A liquid crystal alignment agent filtered through a filter with an average pore size of 1.0 μm was applied by spin coating to the surface of the electrode-equipped substrate and a glass substrate having a 4 μm high columnar spacer with an ITO film deposited on its back surface, and dried on an 80°C hot plate for 2 minutes. Subsequently, the coated surface was exposed to 150-350 mJ / cm² of linearly polarized ultraviolet light with a wavelength of 254 nm and an extinction ratio of 26:1 via a polarizing plate. 2 The substrates were irradiated and then baked in a hot air circulating oven at 230°C for 30 minutes to obtain each substrate with a liquid crystal alignment film with a thickness of 100 nm. Next, a sealant was printed onto one of the pair of glass substrates with liquid crystal alignment films, and the other substrate was bonded to it so that the liquid crystal alignment film surfaces faced each other. The sealant was then cured to create an empty cell. Liquid crystal MLC-3019 (manufactured by Merck) was injected into this empty cell using a reduced-pressure injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour, left overnight, and then used for evaluation.

[0120] [evaluation] <Evaluation of liquid crystal alignment> Using liquid crystal cells before ISO processing, those exhibiting initial flow orientation were classified as "poor," and those without initial flow orientation were classified as "good."

[0121] <Evaluation of seal adhesion> [Sample preparation] The liquid crystal alignment agent prepared above was applied to a 30mm x 40mm ITO substrate by spin coating. After drying on an 80°C hot plate for 2 minutes, the coating surface was irradiated with 254nm ultraviolet light through a polarizing plate, and then baked in a 230°C hot air circulating oven for 20 minutes to form a coating with a thickness of 100nm. Two substrates were prepared in this way, and a 4μm bead spacer was applied to the liquid crystal alignment film surface of one substrate, and then a sealant (XN-1500T manufactured by Kyoritsu Chemical Industry Co., Ltd.) was dropped onto it. Next, the liquid crystal alignment film surface of the other substrate was turned inward, and the substrates were bonded together so that the overlap width was 1cm. At that time, the amount of sealant dropped was adjusted so that the diameter of the sealant after bonding was 3mm. After fixing the two bonded substrates with clips, they were heat-cured at 150°C for 1 hour to prepare a sample for adhesion evaluation.

[0122] [Measurement of seal adhesion] The sample substrate prepared as described above was tested using a desktop precision universal testing machine (AGS-X 500N, manufactured by Shimadzu Corporation). After fixing the edges of the upper and lower substrates, pressure was applied from the top center of the substrate, and the peel strength (N) at which it peeled off was measured. This peel strength (N) was measured over the adhesive area (mm²). 2 ) a value normalized by (peel strength (N) / adhesive area (mm) 2)) Seal adhesion (N / mm) in each sample 2 ) and seal adhesion of 4N / mm 2 A value greater than 4N / mm was rated as "good". 2 The following cases were evaluated as "defective":

[0123] [Table 3] [Industrial applicability]

[0124] The liquid crystal alignment agent of the present invention is useful for forming liquid crystal alignment films in a wide range of liquid crystal display elements, such as those using IPS drive systems and FFS drive systems. Furthermore, the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2019-034305, filed on February 27, 2019, are incorporated herein by reference as disclosure of the present invention.

Claims

1. A liquid crystal display element having a liquid crystal alignment film with a film thickness of 5 to 300 nm, containing a polymer (A) having repeating units represented by the following formula (3) and repeating units represented by the following formula (5). 【Chemistry 1】 (R in equation (3)) ３１ From R ３４ Each of these is independently a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 alkynyl group, a C1-C6 monovalent organic group containing a fluorine atom, or a phenyl group, and may be the same or different, R ３１ From R ３４ At least one of them represents a group other than a hydrogen atom in the above definition. ３ (This represents a divalent organic group represented by the following formula (I).) 【Chemistry 2】 (* indicates a bonding action.) 【Transformation 3】 (R ５１ to R ５４ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, and may be the same or different, but at least one of R ５１ to R ５４ represents a group other than a hydrogen atom in the above definition. Y ５ represents a divalent organic group having a partial structure represented by the following formula (J-1). ) 【Chemistry 4】 (Q ５ is, -(CH ２ ) ｎ Any -CH (where n is an integer between 1 and 20, and n is an even number) ２ -NQ under the condition that the two are not adjacent to each other. ９ CO- or -CONQ ９ It is a base that can be replaced by -. Q ９ Each of these independently represents a hydrogen atom or a monovalent organic group. Q ６ Q ７ Each of these independently represents -H or -NH. (*1 represents a bonding.)

2. The liquid crystal display element according to claim 1, wherein the polymer (A) is a polyimide having an imidization rate of 71% or more.

3. The liquid crystal display element according to claim 1 or 2, wherein the liquid crystal alignment film further contains a compound having at least one group selected from the group consisting of an oxyranyl group, an oxetanyl group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a meldrum acid structure, a cyclocarbonate group, or a group represented by the following formula (d), or a compound represented by the following formula (e) (hereinafter, these are collectively referred to as compound (C)). 【Transformation 5】 (R ７１ This refers to a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH ２ -OH" is R ７２ and R ７３ Each of these independently consists of a hydrogen atom, a C1-C3 alkyl group, or "*-CH ２ This is "-OH". * indicates a bond. A represents an organic group with an aromatic ring and (m+n) valency. m represents an integer from 1 to 6, and n represents an integer from 0 to 4.

4. The sealing adhesion of the liquid crystal alignment film is 4 N / mm². ２ A liquid crystal display element according to any one of claims 1 to 3, which is larger than the specified element.

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