Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display device 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 element using the same. [Background technology]

[0002] Liquid crystal devices have traditionally been widely used as display units for personal computers, mobile phones, smartphones, television sets, etc. Liquid crystal devices include, for example, a liquid crystal layer sandwiched between an element substrate and a color filter substrate, pixel electrodes and a common electrode that apply an electric field to the liquid crystal layer, an alignment film that controls the alignment of liquid crystal molecules in the liquid crystal layer, and thin-film transistors (TFTs) that switch electric signals supplied to the pixel electrodes. Known methods for driving liquid crystal molecules include 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.

[0003] Currently, the most widely used liquid crystal alignment films in industry are prepared by rubbing the surface of a film made of polyamic acid and / or imidized polyimide formed on an electrode substrate in one direction with a cloth made of cotton, nylon, polyester, or the like. Rubbing is a simple, productive, and industrially useful method. However, as liquid crystal display devices become increasingly sophisticated, precise, and large, various problems have emerged, including scratches on the alignment film surface, dust generation, mechanical force and static electricity, and unevenness within the alignment-treated surface. As an alternative to rubbing, a photoalignment method has been proposed, in which liquid crystal alignment ability is imparted by irradiation with polarized radiation. Various methods have been proposed for liquid crystal alignment using photoalignment, including those utilizing photoisomerization, photocrosslinking, and photodecomposition (see Non-Patent Document 1 and Patent Document 1).

[0004] A liquid crystal alignment film, a component of a liquid crystal display element, is a film for uniformly aligning liquid crystals, but various other properties are required in addition to the uniform alignment of liquid crystals. For example, there is a problem that electric charges accumulate in the liquid crystal alignment film due to the voltage used to drive the liquid crystal, which affects the display as afterimages or burn-in (hereinafter referred to as residual DC afterimages) and significantly reduces the display quality of the liquid crystal display element. Therefore, a liquid crystal alignment agent that overcomes these problems has been proposed (see Patent Document 2).

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

[0006] Furthermore, with the spread of tablets and smartphones, development of narrow-framed liquid crystal display elements that ensure as wide a display area as possible is underway. This narrowing of the frame has made it necessary to apply a sealant to the liquid crystal alignment film, and Patent Document 4 discloses a liquid crystal alignment agent that maintains liquid crystal alignment and has good adhesion to the sealant. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 9-297313 [Patent Document 2] International Publication No. 2005 / 083504 Pamphlet [Patent Document 3] International Publication No. 2015 / 050135 Brochure [Patent Document 4] International Publication No. 2015 / 060360 Brochure [Non-patent literature]

[0008] [Non-Patent Document 1] "Liquid Crystal Photo-Alignment Film" Kidowaki, Ichimura, Functional Materials, November 1997, Vol. 17, No. 11, pp. 13-22 Summary of the Invention [Problem to be solved by the invention]

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

[0010] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by using a liquid crystal aligning agent containing a polymer component having a specific repeating unit, and have thus completed the present invention. The present invention is summarized as follows. A liquid crystal aligning agent comprising a polymer (A) having repeating units represented by the following formula (1), (2), (3) and (4): [ka] (R1 to R4 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 and containing a fluorine atom, or a phenyl group, and 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 partial structure represented by the following formula (H): [ka] (Q3 Ha-(CH2) n (n is an integer of 2 to 20), and any -CH2- may be replaced with a group selected from -O- and -C(=O)-, but the oxygen atoms are not 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 five or more members. Y2 is a divalent organic group having a partial structure represented by the above formula (H).) [ka] (R in Equation (3) 31 From R 34 are defined the same as R1 to R4 in the above formula (1), respectively. X4 in formula (4) is defined the same as X2 in the above formula (2). Y3 and Y4 represent divalent organic groups represented by the following formula (I). [ka] (* represents a bond.) [Effects of the Invention]

[0011] According to the liquid crystal alignment agent of the present invention, a liquid crystal alignment film having good liquid crystal alignment properties and good adhesion to the sealing agent can be obtained, and the good adhesion between the liquid crystal alignment film and the sealing agent makes it possible to further narrow the frame, thereby obtaining a liquid crystal display element that exhibits good display quality. DETAILED DESCRIPTION OF THE INVENTION

[0012] Each component contained in the liquid crystal aligning agent of the present invention and other components that may be arbitrarily blended as required will be described below. <Polymer (A)> The liquid crystal aligning agent of the present invention contains a polymer (A) having repeating units represented by the above formula (1), (2), (3), and (4). By adopting such a constitution, a liquid crystal alignment film with little AC afterimage can be obtained, and a liquid crystal display device with excellent contrast can be obtained.

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

[0014] Specific examples of the alkyl group having 1 to 6 carbon atoms in R1 to R4 include a methyl group, an ethyl group, a propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, and an n-pentyl group. Specific examples of the alkenyl group having 2 to 6 carbon atoms in R1 to R4 include a vinyl group, a propenyl group, and a butynyl group, which may be linear or branched. Specific examples of the alkynyl group having 2 to 6 carbon atoms in R1 to R4 include an ethynyl group, a 1-propynyl group, and a 2-propynyl group. Specific examples of the halogen atom in R1 to R4 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Specific examples of the monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom include a fluoromethyl group and a trifluoromethyl group. 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 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 the monovalent organic group substituting any hydrogen atom on the benzene ring in the above formula (H) include 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, and a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, and include the structures exemplified above for R1 to R4. As the partial structure represented by the above formula (H), partial structures represented by any of the following formulae (H-1) to (H-7) can be mentioned, from the viewpoint of reducing the occurrence of AC afterimages. [ka]

[0016] Specific preferred examples of Y1 in the above formula (1) include divalent organic groups represented by any of the following formulae (h-1) to (h-8), from the viewpoint of reducing the occurrence of AC afterimages. [ka]

[0017] The polymer (A) has a repeating unit represented by the above formula (2) from the viewpoint of improving heat resistance. The tetravalent organic group of 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. The alicyclic structure having 5 or more members means that, when the alicyclic structure to which the imide group is bonded is a polycyclic structure, each of the rings contained in the polycyclic structure has 5 or more atoms constituting the ring. The alicyclic structure may be bonded to at least one of the two imide groups, and may have a chain hydrocarbon structure or an aromatic ring structure in addition to the alicyclic structure.

[0018] Preferred specific examples of X2 include tetravalent organic groups represented by any of the following formulae (X2-1) to (X2-12). [ka]

[0019] In particular, X2 in formula (2) is more preferably any one of (X2-1) to (X2-4) from the viewpoint of reducing the occurrence of AC afterimages and increasing the contrast of the liquid crystal display element. Preferable specific examples of Y2 in the above formula (2) are the same as the preferable specific examples of Y1 in the above formula (1).

[0020] In order to reduce AC afterimages, the polymer (A) preferably contains 1 to 95 mol %, more preferably 5 to 90 mol %, of the total repeating units of the repeating units represented by the formula (1) and the repeating units represented by the formula (2), based on the total repeating units. The ratio ((1):(2)) of the repeating units represented by the formula (1) to the repeating units represented by the formula (2) in the 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] The polymer (A) has a repeating unit represented by the above formula (3) and a repeating unit represented by the above formula (4) from the viewpoint of improving the contrast and seal adhesion of a liquid crystal display device. From the viewpoint of reducing AC afterimages, the polymer (A) preferably contains 5 to 99 mol %, and more preferably 10 to 95 mol %, of the total of the repeating units represented by the formula (3) and the repeating units represented by the formula (4) based on all the repeating units. The ratio ((3):(4)) of the repeating units represented by the formula (3) to the repeating units represented by the formula (4) in the 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 the formula (1) to the repeating units represented by the formula (3) in the 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 the formula (2) to the repeating units represented by the formula (4) in the 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 %, and more preferably 15 to 100 mol %, of the total repeating units represented by the above formulas (1), (2), (3) and (4) based on the total repeating units contained in the polymer (A).

[0024] From the viewpoint of further enhancing adhesion to a sealing agent, the polymer (A) may have at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (5) and a repeating unit represented by the following formula (6): [ka] (R 51 From R 54 are each synonymous with R1 to R4 in the above formula (1), including preferred specific examples, and Y5 and Y6 each independently represent a divalent organic group having a partial structure represented by the following formula (J-1) or a divalent organic group represented by the following formula (J-2). X6 in formula (6) is synonymous with X2 in the above formula (2). [ka]

[0025] In the above formulas (J-1) and (J-2), Q5 represents a single bond, -(CH2) n -(n is an integer of 1 to 20), or -(CH2) n -O-, -COO-, -OCO-, -NQ9-, -NQ9CO-, -CONQ9-, -NQ9CONQ, provided that any -CH2- in 10 Q and Q are groups that can be replaced by -, -NQCOO-, or -OCOO-. 10 each independently represents a hydrogen atom or a monovalent organic group. Furthermore, Q6 and Q7 each independently represent -H, -NHD, -N(D)2, a group having -NHD, or a group having -N(D)2. Q8 represents -NHD, -N(D)2, a group having -NHD, or a group having -N(D)2. D represents a carbamate protecting group, and examples of the carbamate protecting group include a tert-butoxycarbonyl group and a 9-fluorenylmethoxycarbonyl group. However, at least one of Q5, Q6, and Q7 has a carbamate protecting group in the group. *1 represents a bond.

[0026] Specific preferred examples of Y5 and Y6, from the viewpoint of reducing AC afterimages, include divalent organic groups represented by any one of the following formulae (J-1-a) to (J-1-d) and (J-2-1): Boc represents a tert-butoxycarbonyl group. [ka]

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

[0028] In formula (PI-A-1), X I1 represents a tetravalent organic group, and Y I1 represents a divalent organic group. I1 is a tetravalent organic group represented by the following formula (g) or has the same meaning as X2 in the above formula (2), Y I1 represents a structure other than a divalent organic group having a partial structure represented by the above formula (H), a divalent organic group represented by the above formula (I), a divalent organic group having a partial structure represented by the above formula (J-1), and a divalent organic group represented by the above formula (J-2). X I1Examples of the tetravalent organic group include the tetravalent organic groups represented by the following formula (g), the tetravalent organic groups exemplified as X2 in the above formula (2), and the tetravalent organic groups represented by the following formula (X I1 -1)~(X I1 -13), and a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride. [ka] (R1, R2, R3, and R4 have the same meanings as R1, R2, R3, and R4 in the above formula (1).)

[0029] [ka]

[0030] Above X 11 The aromatic tetracarboxylic acid dianhydride that gives the tetravalent organic group is an acid dianhydride obtained by intramolecular dehydration of a carboxyl group bonded to an aromatic ring such as a benzene ring or a naphthalene ring. Specific examples include a tetravalent organic group represented by any one of the following formulae (X3-1) to (X3-2) and a tetravalent organic group represented by any one of the following formulae (Xr-1) to (Xr-7). [ka] (x and y each independently represent a single bond, an ether (—O—), a carbonyl (—CO—), an ester (—COO—), an alkanediyl group having 1 to 5 carbon atoms, 1,4-phenylene, a sulfonyl, or an amido group. j and k are 0 or 1. * represents a bond.) [ka]

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

[0032] [ka]

[0033] [ka]

[0034] In formula (PA-1), X A1 represents a tetravalent organic group, and Y A1 represents a divalent organic group. A1 Specific examples of X in the above formula (PI-A-1) include I1 Examples of the structure are shown in Y A1 Specific examples of the above include Y in the formula (PI-A-1). I1 Examples of the structure are shown in

[0035] In formula (PA-1), R A1 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. A11 , Z A12 are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkenyl group having 2 to 10 carbon atoms which may have a substituent, an alkynyl group having 2 to 10 carbon atoms which may have a substituent, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group.

[0036] Above R A1Specific examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, a propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, an n-pentyl group, etc. From the viewpoint of ease of imidization by heating, R1 is preferably a hydrogen atom or a methyl group.

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

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

[0039] In the polymer (A), the sum of the repeating units represented by the formula (5) and the repeating units represented by the formula (6) is preferably 1 to 40 mol %, more preferably 1 to 30 mol %, and even more preferably 5 to 30 mol %, based on the total repeating units contained in the polymer (A). In this case, the total amount of repeating units represented by the above formulas (1), (2), (3) and (4) is preferably 6 to 99 mol%, more preferably 15 to 99 mol%, and still more preferably 15 to 95 mol%, based on all repeating units contained in the polymer (A).

[0040] <Second polymer> The liquid crystal aligning agent of the present invention is a composition containing the polymer (A) and an organic solvent, and may contain two or more polymers (A) having different structures. The liquid crystal aligning agent of the present invention may also contain a polymer other than the polymer (A) (hereinafter also referred to as a second polymer) and various additives. When the liquid crystal aligning agent of the present invention contains a second polymer, the content of the polymer (A) relative to the total polymer components is preferably 5% by mass or more, more preferably 5 to 95% by mass, and even 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 derivative, poly(styrene-phenylmaleimide) derivative, and poly(meth)acrylate.

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

[0043] An example of the tetracarboxylic dianhydride component for obtaining the second polyamic acid is a compound represented by the following formula (11): The tetracarboxylic dianhydride component may be composed of two or more types of compounds. [ka] (A is a tetravalent organic group, preferably a tetravalent organic group having 4 to 30 carbon atoms.)

[0044] Preferred examples of A are shown below, but the invention is not limited to these. [ka]

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

[0046] The diamine component for obtaining the second polyamic acid can be appropriately determined depending on the purpose, and for example, a diamine represented by the following formula (12) can be used. [ka] (Y9 represents a divalent organic group. Two A9s each independently represent 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 alignment, A9 is preferably a hydrogen atom or a methyl group.)

[0047] For the purpose of improving the 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 the diamine represented by formula (12) when Y9 is a divalent organic group having a secondary or tertiary nitrogen atom include any of the following diamines (a) to (d).

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

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

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

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

[0052] (d) diamines having a nitrogen-containing heterocycle as described in paragraphs

[0173] to

[0188] of WO2015 / 046374, diamines having a nitrogen-containing structure as described in paragraph

[0050] of JP2016-218149, and diamines represented by the following formula (BP): [ka] (X is a biphenyl ring or a fluorene ring; Y is a benzene ring, a biphenyl ring, or a group selected from -Ph-Z-Ph-, where Ph is 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-triazine 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-ethoxyacridine lactate, 3,8-di Amino-6-phenylphenanthridine, 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 formula (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 -CH2- of the divalent chain hydrocarbon group 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-, -NR- (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 formula (13) below when A1 is -NH-CO-NH-, or a group in which at least one -CH2- in an alkylene group having 2 to 20 carbon atoms is substituted with -NH-CO-NH-, or a group in which at least one -CH2- in an alkylene group having 2 to 20 carbon atoms is substituted with -NH-CO-NH- and at least one 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). More preferred specific examples of diamines include diamines 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 (provided that any -CH2- in 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 hydroxy group, or an alkyl or alkoxy group having 1 to 5 carbon atoms (any hydrogen atom in the alkyl or alkoxy group may be substituted with a halogen atom). a represents an integer of 0 to 4, and when a is 2 or greater, A2s 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 diamines represented by any of the following formulae (n3-1) to (n3-7) and diamines represented by any of the following formulae (n4-1) to (n4-6). [ka]

[0058] [ka]

[0059] To improve printability, diamines having a carboxyl group (COOH group) or a hydroxyl group (OH group) can also be used. Specific 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, and 3,5-diaminobenzoic acid. Among these, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, and 3,5-diaminobenzoic acid are preferred. Diamines represented by the following formulas [3b-1] to [3b-4], or diamines in which the amino group is a secondary amino group, can also be used.

[0060] [ka]

[0061] In formula [3b-1], Q 1 represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -C2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)- or N(CH3)CO-; m 1 and m 2 each independently represents an integer of 0 to 4, and m 1 +m 2 represents an integer of 1 to 4. In formula [3b-2], m 3 and m 4 Each independently represents an integer of 1 to 5. In formula [3b-3], Q 2 represents a linear or branched alkylene group having 1 to 5 carbon atoms, m 5 represents an integer of 1 to 5. In formula [3b-4], Q 3 and Q 4each independently represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -C2O-, -OCH2-, -COO-, -OCO, -CON(CH3)- or -N(CH3)CO-; m 6 represents an integer from 1 to 4.)

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

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

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

[0065] The liquid crystal aligning agent is used to prepare a liquid crystal alignment film, and takes the form of a coating liquid from the viewpoint of forming a uniform thin film. The liquid crystal aligning agent of the present invention is also preferably a coating liquid containing the above-mentioned polymer component and an organic solvent. In this case, the concentration (content) of the polymer in the liquid crystal aligning agent can be appropriately changed depending on the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, it is preferably 1% by mass or more, and from the viewpoint of storage stability of the solution, it is preferably 10% by mass or less. A particularly preferred polymer concentration is 2 to 8% by mass.

[0066] The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as it is a solvent (also called a good solvent) in which the polymer component is uniformly dissolved. 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, and γ-butyrolactone are preferred. The good solvent preferably accounts for 20 to 99 mass % of the total solvent contained in the liquid crystal aligning agent, more preferably 20 to 90 mass %, and particularly preferably 30 to 80 mass %.

[0067] In addition, the organic solvent contained in the liquid crystal aligning agent is preferably a mixed solvent containing a good solvent and a solvent (also called a poor solvent) that improves the coating properties when coating the liquid crystal aligning agent and the surface smoothness of the coating film. Specific examples of poor solvents are listed below, but are not limited to these examples. For example, diisopropyl ether, diisobutyl ether, diisobutyl carbinol (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) 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, diisobutyl ketone (2,6-dimethyl-4-heptanone), and the like.

[0068] Of these, the poor solvent is preferably 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.

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

[0070] The liquid crystal aligning agent of the present invention may additionally contain components other than the polymer component and the organic solvent. Such additional components include an adhesion aid for improving the adhesion between the liquid crystal alignment film and the substrate or between the liquid crystal alignment film and the sealant, a compound for increasing the strength of the liquid crystal alignment film (hereinafter also referred to as a crosslinking compound), a dielectric or conductive substance for adjusting the dielectric constant or electrical resistance of the liquid crystal alignment film, etc.

[0071] As the crosslinkable compound, from the viewpoint of generating less AC afterimages and having a high effect of improving film strength, a compound having at least one group selected from the group consisting of an oxiranyl group, an oxetanyl group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Meldrum's acid structure, a cyclocarbonate group, and a group represented by the following formula (d), or a compound represented by the following formula (e) (hereinafter these are also collectively referred to as compound (C)). [ka] (R 71 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "-CH-OH". 72 and R 73 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH". * represents a bond. A represents an (m+n)-valent organic group having an aromatic ring. m represents an integer of 1 to 6, and n represents an integer of 0 to 4.

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

[0037] of Japanese Patent Application Laid-Open No. 10-338880 and compounds having a triazine ring skeleton described in WO2017 / 170483. Among these, particularly preferred are compounds containing nitrogen atoms, such as N,N,N',N'-tetraglycidyl-m-xylylenediamine, 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): [ka]

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

[0170] to

[0175] of WO2011 / 132751.

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

[0046] to

[0047] of JP 2014-224978 A, and compounds having three or more protected isocyanate groups described in

[0119] to

[0120] of WO 2015 / 141598 A. Among these, compounds represented by any of the following formulae (bi-1) to (bi-3) are preferred. [ka]

[0075] Specific examples of compounds having a protected isothiocyanate group include compounds having two or more protected isothiocyanate groups described in JP 2016-200798 A. Specific examples of compounds having a group containing an oxazoline ring structure include compounds containing two or more oxazoline structures described in

[0115] of Japanese Patent Application Laid-Open No. 2007-286597.

[0076] Specific examples of compounds having a group containing a Meldrum's acid structure include compounds having two or more Meldrum's acid structures described in WO2012 / 091088. Specific examples of compounds having a cyclocarbonate group include compounds described in WO2011 / 155577. Examples of the alkyl group having 1 to 3 carbon atoms for R1, R2, and R3 in the group represented by the above formula (d) include a methyl group, an ethyl group, and a propyl group.

[0077] Specific examples of compounds having a group represented by the above formula (d) include compounds having two or more groups represented by the above formula (d) described in WO2015 / 072554 and JP 2016-118753 A

[0058] , compounds described in JP 2016-200798 A, etc. Among these, compounds represented by any of the following formulas (hd-1) to (hd-8) are preferred.

[0078] [ka]

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

[0080] [ka]

[0081] The above compounds are examples of crosslinkable compounds, and are not limited thereto. For example, components other than those described above may be mentioned in paragraphs

[0105] to

[0116] of WO2015 / 060357. In addition, two or more types of crosslinkable compounds may be combined to be contained in the liquid crystal aligning agent of the present invention. The content of the crosslinkable compound in the liquid crystal aligning agent of the present invention is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent, and more preferably 1 to 15 parts by mass from the viewpoint of promoting the crosslinking reaction to exhibit the desired effect and minimizing the occurrence of AC afterimages.

[0082] Examples of the adhesion aid 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-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, 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-isocyanatepropyltriethoxysilane. The amount of these silane coupling agents used is preferably 0.1 to 30 parts by mass, 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, from the viewpoint of reducing the occurrence of AC afterimages.

[0083] <Method of manufacturing liquid crystal alignment film> A liquid crystal alignment film using the liquid crystal aligning agent of the present invention can be produced by a known method for obtaining a liquid crystal alignment film from a liquid crystal aligning agent, using the above-mentioned liquid crystal aligning agent of the present invention. In particular, a liquid crystal alignment film using the liquid crystal aligning agent of the present invention can be efficiently produced by sequentially carrying out the following steps (1), (2), (3), and preferably step (4).

[0084] <Process (1)> This is a process of applying the liquid crystal aligning agent of the present invention to a substrate. The substrate to which the liquid crystal aligning agent is applied is not particularly limited as long as it is a highly transparent substrate, and glass substrates, silicon nitride substrates, and plastic substrates such as acrylic substrates and polycarbonate substrates can also be used. In this case, it is preferable to use a substrate on which an ITO electrode for driving the liquid crystal is formed, from the viewpoint of simplifying the process. Furthermore, in a reflective liquid crystal display element, one of the substrates can be an opaque material such as a silicon wafer, and in this case, a light-reflecting material such as aluminum can also be used for the electrode. Industrially, the liquid crystal aligning agent is generally applied by screen printing, offset printing, flexographic printing, inkjet printing, etc. Other application methods include a dipping method, a roll coating method, a slit coating method, a spinner method, a spray method, etc., and these may be used depending on the purpose.

[0085] <Process (2)> Step (2) is a step of heating the coating film of the liquid crystal aligning agent obtained in step (1). After the liquid crystal aligning agent is applied to the substrate, 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 circulation oven, or an IR (infrared) oven. The drying and baking steps after application of the liquid crystal aligning agent can be performed at any temperature and for any time, and may be performed multiple times. The temperature for removing the organic solvent from the liquid crystal aligning agent can be, for example, 40 to 150°C. To shorten the process, the temperature can be 40 to 120°C. The baking time is not particularly limited, but can be 1 to 10 minutes or 1 to 5 minutes. When thermally imidizing the amic acid or amic acid ester in the polymer, the polymer can be baked at, for example, 190 to 250°C or 200 to 240°C after the organic solvent removal step. The baking time is not particularly limited, but can be 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, more preferably 200 to 300 nm. To improve the liquid crystal alignment, the substrate coated with the liquid crystal alignment film may be irradiated with ultraviolet light while being heated at 50 to 250°C. The radiation dose is 1 to 10,000 mJ / cm. 2 is preferred, and 100 to 5,000 mJ / cm 2 The liquid crystal alignment film thus prepared can stably align the liquid crystal molecules in a certain direction. The higher the extinction ratio of the polarized UV light, the higher the anisotropy that can be imparted, which is preferable. Specifically, the extinction ratio of linearly polarized UV light is preferably 10:1 or greater, and more preferably 20:1 or greater.

[0087] <Process (4)> Step (4) is a step of firing the film obtained in step (3) at 100°C or higher and at a temperature higher than that 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 is preferably 150 to 300°C, more preferably 150 to 250°C, and even more preferably 200 to 250°C. 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 baking is preferably 5 to 300 nm, more preferably 10 to 200 nm, since if it is too thin, the reliability of the liquid crystal display element may decrease.

[0088] Furthermore, after carrying out either the step (3) or (4) above, the obtained liquid crystal alignment film can be subjected to a contact treatment using water and / or a solvent. The solvent used in the contact treatment is not particularly limited as long as it dissolves the decomposition products generated from the liquid crystal alignment film upon irradiation with ultraviolet light. 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, and cyclohexyl acetate. Among these, water, 2-propanol, 1-methoxy-2-propanol, and ethyl lactate are preferred in terms of versatility and solvent safety. Water, 1-methoxy-2-propanol, and ethyl lactate are more preferred. Two or more solvents may be used in combination.

[0089] Examples of the contact treatment, i.e., a method of treating the liquid crystal alignment film irradiated with polarized UV light with water or a solvent, include immersion treatment and spray treatment (also called spray treatment). The treatment time in these treatments is preferably 10 seconds to 1 hour in order to efficiently dissolve decomposition products generated from the liquid crystal alignment film by UV light. Of these, immersion treatment for 1 to 30 minutes is preferred. The solvent during the contact treatment may be at room temperature or heated, but is preferably 10 to 80°C. Of these, 20 to 50°C is preferred. In addition, ultrasonic treatment or the like may be performed as necessary in order to improve the solubility of the decomposition products.

[0090] After the contact treatment, it is preferable to rinse the liquid crystal alignment film with a low-boiling solvent such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone, or to bake the liquid crystal alignment film. Either rinsing or baking may be performed, or both may be performed. The baking temperature is preferably 150 to 300°C, more preferably 180 to 250°C, and more preferably 200 to 230°C. The baking 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 in-plane switching mode liquid crystal display elements such as IPS mode and FFS mode, and is particularly useful as a liquid crystal alignment film for FFS mode liquid crystal display elements. The liquid crystal display element is obtained by obtaining a substrate with a liquid crystal alignment film obtained from a liquid crystal aligning agent, and then producing a liquid crystal cell by a known method, and using the liquid crystal cell. As an example of a method for fabricating a liquid crystal cell, a passive matrix liquid crystal display element will be described. However, an active matrix liquid crystal display element in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion that constitutes an image display may also be used.

[0092] Specifically, transparent glass substrates are prepared, and a common electrode is provided on one substrate and segment electrodes are provided on the other substrate. These electrodes can be, for example, ITO electrodes and are patterned to display the desired image. Next, an insulating film is provided on each substrate so as to cover the common electrode and segment electrodes. The insulating film can be, for example, a SiO2-TiO2 film formed by the sol-gel method. Next, a liquid crystal alignment film is formed on each substrate, and one substrate is placed on the other substrate with the liquid crystal alignment film facing each other, and the periphery is bonded with a sealant. Spacers are typically mixed into the sealant to control the gap between the substrates. It is also preferable to spray spacers for controlling the gap between the substrates on the inner surfaces where no sealant is applied. An opening is provided in a portion of the sealant to allow liquid crystal to be filled from the outside. Next, liquid crystal material is injected into the space surrounded by the two substrates and sealant through the opening in the sealant, and the opening is then sealed with an adhesive. The injection can be performed using a vacuum injection method or a method utilizing capillary action in the atmosphere. Either a positive-type or negative-type liquid crystal material can be used as the liquid crystal material. Next, polarizers are installed. Specifically, a pair of polarizers are attached to the surfaces of the two substrates opposite the liquid crystal layer.

[0093] As described above, by using the manufacturing method of the present invention, it is possible to suppress the occurrence of image retention due to long-term AC driving in IPS drive type or FFS drive type liquid crystal display elements. Furthermore, by removing the organic solvent at 40 to 150°C in step (2) and then performing step (3), a liquid crystal alignment film can be obtained with fewer steps than conventional methods. The liquid crystal aligning agent of the present invention can be particularly preferably used in a manufacturing method of a liquid crystal alignment film, which includes a step of removing the organic solvent at 40 to 150°C in step (2) and then performing step (3).

[0094] As described above, by using the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal alignment film with high seal adhesion and with little residual DC-derived afterimage or AC afterimage. In particular, it is possible to obtain a liquid crystal display element with excellent contrast in which the in-plane brightness variation during black display is suppressed, and a liquid crystal display element with good display quality can be obtained. [Example]

[0095] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The abbreviations for compounds and the methods for measuring the respective properties 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: A compound represented by the following formula (C-1): C-2: 2,2'-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane S-1: a compound represented by the following formula (S-1):

[0096] [ka]

[0097] [ka]

[0098] [ka]

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

[0100] <Measurement of imidization rate> 20 mg of polyimide powder was placed in an NMR sample tube (NMR sampling tube standard, φ5 (Kusano Scientific Co., Ltd.)), and deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) (0.53 mL) was added. The solution was then sonicated to completely dissolve it. Proton NMR at 500 MHz was measured using an NMR spectrometer (JNW-ECA500) (JEOL Datum Co., Ltd.). The imidization ratio was calculated using the integrated peak value of this proton and the integrated peak value of the proton derived from the NH group of the amic acid, which appeared around 9.5 ppm to 10.0 ppm, according to the following equation: Imidization rate (%) = (1 - α x / y) x 100 In the above formula, x is the integrated value of the proton peak derived from the NH group of the amide acid, y is the integrated value of the peak of the reference proton, and α is the ratio of the number of reference protons to one NH group proton of the amide acid in the case of polyamide acid (imidization rate 0%).

[0101] [Polymer synthesis example] Examples of synthesizing polyamic acid and polyimide are shown below, where PI stands for polyimide.

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

[0103] <Synthesis Example 2> 4.10 g (0.0168 mol) of DA-1 and 8.32 g (0.0392 mol) of DA-3 were weighed into a 200 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, 176 g of NMP was added, and the mixture was stirred and dissolved while supplying nitrogen. 11.6 g (0.0518 mol) of CA-1 was added while stirring this diamine solution, 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> 6.37 g (0.03 mol) of DA-3 was weighed into a 100 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and 92.3 g of NMP was added. The mixture was stirred and dissolved under nitrogen. 6.22 g (0.0278 mol) of CA-1 was added to the diamine solution while stirring, and the mixture was stirred at 40°C for 24 hours to obtain a polyamic acid solution (A-3) (viscosity: 347 mPa s).

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

[0106] <Synthesis Example 5> 3.23 g (0.0084 mol) of DA-2 and 4.16 g (0.0196 mol) of DA-3 were weighed into a 200 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and 97.3 g of NMP was added. While stirring, 5.52 g (0.0246 mol) of CA-1 and 0.35 g (0.0014 mol) of CA-2 were added to the diamine solution, 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> 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 into a 200 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and 95.1 g of NMP was added. While stirring, 5.52 g (0.0246 mol) of CA-1 and 0.35 g (0.0014 mol) of CA-2 were added to the diamine solution. 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> 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 into a 200 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and 95.3 g of NMP was added. While stirring, 5.21 g (0.0232 mol) of CA-1 and 0.700 g (0.0028 mol) of CA-2 were added to the diamine solution. 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> 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 into a 200 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and 95.6 g of NMP was added. While stirring, 4.90 g (0.0218 mol) of CA-1 and 1.05 g (0.0042 mol) of CA-2 were added to the diamine solution. 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 resulting polyamic acid solution (A-1) was placed in a 100 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and 11.7 g of NMP was added and stirred for 30 minutes. To the resulting polyamic acid solution, 2.84 g (3 molar equivalents relative to the polyamic acid) of acetic anhydride and 0.73 g (equivalent to the molar equivalent of the polyamic acid) of pyridine were added and heated at 50 °C for 3 hours to carry out chemical imidization. The resulting reaction solution was poured into 150 mL of methanol with stirring, and the precipitate was collected by filtration. The same procedure was repeated twice to wash the resin powder, which was then dried at 60 °C for 12 hours to obtain a 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, and 26.4 g of NMP was added to give a solids concentration of 12%, followed by stirring at 70°C for 24 hours to dissolve the powder, yielding a polyimide solution (A-1-PI).

[0111] <Synthesis Examples 10-16> The same procedures as in Synthesis Example 9 were carried out except that the raw materials listed in Table 1 below were used. The specifications of the polyimides obtained in Synthesis Examples 10 to 16 are shown in Table 1 together with those of Synthesis Example 9. [Table 1]

[0112] The numbers in parentheses in Table 1 indicate the proportion (parts by mole) of each compound for the tetracarboxylic acid component relative to 100 parts by mole of the total amount of tetracarboxylic acid derivatives used in the synthesis, and the proportion (parts by mole) of each compound for the diamine component relative to 100 parts by mole of the total amount of diamines used in the synthesis. The numbers in parentheses indicate 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> 7.5 g of the polyimide solution (A-1-PI) was weighed out into a 20 ml sample tube containing a stir bar, and 2.23 g of NMP, 5.10 g of GBL, 4.0 g of BCS, 0.90 g of a GBL solution containing 1 wt % of S-1, and 0.27 g of an NMP solution containing 10 wt % of C-1 were added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal alignment agent (R1).

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

[0115] <Examples 2 to 6, Comparative Example 3> In Examples 2 to 6 and Comparative Example 3, each liquid crystal aligning agent was obtained in the same manner as in Comparative Example 1 and Example 1, except that each polyimide solution, additive, and organic solvent listed in the following Table 2 was used. The specifications of each obtained liquid crystal aligning agent are shown in Table 1, along with the liquid crystal aligning agents of Example 1 and Comparative Example 1.

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

[0117] <Fabrication of Liquid Crystal Display Element> A substrate with electrodes was prepared. The substrate was a 30mm x 35mm, 0.7mm thick glass substrate. A solid-patterned IZO electrode, which constitutes the counter electrode, was formed on the substrate. A SiN (silicon nitride) film was deposited by CVD on the first counter electrode as the second layer. The second SiN film was 500nm thick and functioned as an interlayer insulating film. A comb-shaped pixel electrode, formed by patterning an IZO film as the third layer, was placed on top of the second SiN film, forming two pixels: the first and second pixels. Each pixel measured 10mm long and approximately 5mm wide. The first counter electrode and the third pixel electrode were electrically insulated by the second SiN film.

[0118] The pixel electrode in the third layer has a comb-like shape, consisting of multiple electrode elements arranged in a "L" shape with a bent center. The width of each electrode element in the short direction is 3 μm, and the spacing between the electrode elements is 6 μm. Because the pixel electrode that forms each pixel is arranged in multiple electrode elements arranged in a "L" shape with a bent center, each pixel is not rectangular, but rather has a shape resembling a bold "L" shape, which is bent in the center like the electrode elements. Each pixel is divided into upper and lower sections by the bent center, with a first region above the bent section and a second region below the bent section.

[0119] A liquid crystal alignment agent filtered through a filter with an average pore size of 1.0 μm was spin-coated onto the surface of each of the above-mentioned electrode-attached substrate and a glass substrate with a 4 μm-high columnar spacer and an ITO film formed on the backside, and then dried on a hot plate at 80°C for 2 minutes. Then, linearly polarized ultraviolet light with a wavelength of 254 nm and an extinction ratio of 26:1 was irradiated onto the coated surface through a polarizer at 150 to 350 mJ / cm. 2 The coating was then irradiated and baked in a hot air circulating oven at 230° C. for 30 minutes to obtain substrates with a liquid crystal alignment film having a thickness of 100 nm. Next, a sealant was printed on one of the pair of glass substrates with liquid crystal alignment films, and the other substrate was attached so that the liquid crystal alignment film faces the other substrate. The sealant was then cured to prepare an empty cell. Liquid crystal MLC-3019 (manufactured by Merck) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. The resulting liquid crystal cell was then heated at 120°C for 1 hour and left overnight before being used for evaluation.

[0120] [evaluation] <Evaluation of liquid crystal alignment> Using liquid crystal cells before the ISO treatment, those with initial flow alignment were rated as "bad" and those without initial flow alignment were rated as "good."

[0121] <Evaluation of seal adhesion> [Sample production] The liquid crystal alignment agent prepared above was spin-coated onto a 30 mm x 40 mm ITO substrate. After drying for 2 minutes on a hot plate at 80 °C, the coating surface was irradiated with 254 nm UV light through a polarizer and then baked for 20 minutes in a hot air circulating oven at 230 °C to form a 100 nm thick coating. Two substrates were prepared in this manner. 4 μm bead spacers were applied to the liquid crystal alignment film surface of one substrate, followed by the application of a sealant (XN-1500T, manufactured by Kyoritsu Chemical Industry Co., Ltd.). The other substrate was then bonded with the liquid crystal alignment film facing inward, resulting in a 1 cm overlap. The amount of sealant applied was adjusted so that the diameter of the sealant after bonding was 3 mm. The two bonded substrates were secured with clips and thermally cured at 150 °C for 1 hour to prepare a sample for adhesion evaluation.

[0122] [Seal adhesion measurement] The sample substrates prepared above were fixed at the edges of the top and bottom substrates in a tabletop precision universal testing machine (AGS-X 500N, manufactured by Shimadzu Corporation), and the strength (N) at the time of peeling was measured by pressing the substrates from above the center. This peel strength (N) was calculated based on the adhesive area (mm 2 ) normalized by (peel strength (N) / adhesion area (mm 2)) for each sample was measured to determine the seal adhesion (N / mm 2 ) and the seal adhesion is 4N / mm 2 A value greater than 4 N / mm was evaluated as "good." 2 The following cases were evaluated as "poor".

[0123] [Table 3] [Industrial Applicability]

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

Claims

1. A liquid crystal display device comprising a polymer (A) having a repeating unit represented by the following formula (3) and a repeating unit represented by the following formula (5), and having a liquid crystal alignment film with a film thickness of 5 to 300 nm: 【Chemical 1】 (R in formula (3) ３１ From R ３４ 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 and containing a fluorine atom, or a phenyl group, and may be the same or different. ３１ From R ３４ At least one of Y represents a group other than a hydrogen atom as defined above. ３ represents a divalent organic group represented by the following formula (I): 【Chemistry 2】 (* represents a bond.) 【Chemistry 3】 (R ５１ From 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 and containing a fluorine atom, or a phenyl group, and may be the same or different. ５１ From R ５４ At least one of Y represents a group other than a hydrogen atom as defined above. 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 -(n is an integer of 1 to 20, and n is an even number) ２ -NQ under the condition that - is not adjacent to each other ９ CO- or -CONQ ９ - is a group that can be replaced by Q. ９ each independently represents a hydrogen atom or a monovalent organic group. ６ , Q ７ are each independently -H, -NHD, -N(D) ２ , a group having —NHD, or —N(D) ２ D represents a carbamate protecting group. *1 represents a bond.

2. 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. 3. The liquid crystal display element according to claim 1, wherein the liquid crystal alignment film further contains a compound having at least one group selected from the group consisting of an oxiranyl group, an oxetanyl group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Meldrum's acid structure, a cyclocarbonate group, and 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)). 【Chemistry 5】 (R ７１ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH ２ -OH". R ７２ and R ７３ are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH ２ -OH". * indicates a bond. A represents an (m+n)-valent organic group having an aromatic ring. m represents an integer of 1 to 6, and n represents an integer of 0 to 4.

4. The seal adhesion of the liquid crystal alignment film is 4 N / mm ２ 4. The liquid crystal display element according to claim 1, wherein

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