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

Abstract

Provided is a liquid crystal alignment film which has a high refractive index and ensures a high light transmittance, and which has fast relaxation of accumulated charges and excellent afterimage characteristics.　A liquid crystal alignment agent contains a polymer component having: a first repeating unit (a1) selected from the group consisting of a repeating unit represented by formula (1) and an imidized structure of the repeating unit represented by formula (1); and a second repeating unit (a2) selected from the group consisting of a repeating unit represented by formula (2) and an imidized structure of the repeating unit represented by formula (2). (X1 and X2 represent a tetravalent organic group. Y1 represents a divalent organic group having a structure represented by formula (S). Y2 represents a divalent organic group having a partial structure represented by formula (2c). Two R1's and R2's each independently represent a hydrogen atom or a monovalent organic group. Two Z1's and Z2's each independently represent a hydrogen atom or a monovalent organic group.) (X and J are as defined in the specification.) (Any hydrogen atom on the benzene ring may be substituted with a monovalent substituent.)

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. [Background technology]

[0002] Liquid crystal display elements are widely used in a wide range of applications, from small devices such as mobile phones and smartphones to relatively large devices such as televisions and monitors. Liquid crystal display elements are generally constructed by arranging a pair of electrode substrates facing each other with a predetermined gap (several μm) between them and sealing liquid crystal between the electrode substrates. Images are displayed on the liquid crystal display element by applying a voltage between the transparent conductive films that make up the electrodes of the electrode substrates. These liquid crystal display elements have a liquid crystal alignment film, which is essential for controlling the alignment state of liquid crystal molecules.

[0003] Meanwhile, various driving methods have been developed for liquid crystal display elements, which differ in electrode structure, physical properties of the liquid crystal molecules used, etc. For example, various modes such as TN (Twisted Nematic) mode, STN (Super Twisted Nematic) mode, VA (Vertical Alignment) mode, IPS (In-Plane Switching) mode, and FFS (fringe field switching) mode are known. Among these, VA (vertical alignment) liquid crystal display elements have a wide viewing angle, a fast response speed, high contrast, and can eliminate the need for rubbing treatment in the production process, and are therefore widely used, particularly for televisions and monitors, for which there is a high demand for larger displays. The mainstream of VA liquid crystal display elements uses the PSA method, in which a photopolymerizable compound is added to the liquid crystal composition in advance, and ultraviolet light is irradiated onto the liquid crystal cell while a voltage is applied, thereby increasing the response speed of the liquid crystal (see Patent Documents 1 and 2).

[0004] A liquid crystal alignment film is required to have various properties in addition to liquid crystal alignment. For example, in the PSA liquid crystal display element, if static electricity accumulates in the liquid crystal cell, the accumulated charge can affect the display by disturbing the liquid crystal alignment or causing image retention, which can significantly reduce the display quality of the liquid crystal element. For this reason, a liquid crystal alignment film that suppresses the accumulation of static electricity and reduces image retention is required. Patent Document 3 proposes a polyimide liquid crystal alignment film having a pyrrole structure as a liquid crystal alignment film that solves these problems. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2003-149647 [Patent Document 2] International Publication No. 2011 / 132752 [Patent Document 3] International Publication No. 2019 / 013339 Summary of the Invention [Problem to be solved by the invention]

[0006] In addition to the above, in recent years, in ultra-high definition liquid crystal display elements such as 4K and 8K, the occupancy rate of black matrix (BM) and TFT has increased, reducing the aperture ratio of the panel, so improving the light transmittance of the display area has become important. On the other hand, the transparent conductive film in a liquid crystal display element is usually formed from a composition (ITO) mainly composed of indium oxide doped with a few percent of tin oxide. However, its refractive index is higher than that of the liquid crystal alignment film. Therefore, when light from a display light source is transmitted through the electrode substrates, the light is reflected at the interface between the transparent conductive film and the liquid crystal alignment film on each electrode substrate. As a result, the light transmittance of the electrode substrate cannot be sufficiently obtained, resulting in a problem of reduced display brightness. In particular, when a liquid crystal alignment film that exhibits vertical alignment is used, the difference in refractive index between the liquid crystal alignment film and the transparent conductive film becomes large, causing a serious problem of reduced display brightness. A method using a polyimide liquid crystal alignment film having a pyrrole structure as described in Patent Document 3 is also conceivable, but since this structure has colorability, a liquid crystal alignment film different from that of conventional techniques has been desired.

[0007] In view of the above circumstances, the object of the present invention is to provide a liquid crystal alignment film that has a high refractive index, high light transmittance, rapid relaxation of accumulated charges, and excellent afterimage characteristics, as well as to provide a liquid crystal alignment agent for obtaining the liquid crystal alignment film, and a liquid crystal display element using the liquid crystal alignment film. [Means for solving the problem]

[0008] As a result of intensive research into achieving the above object, the present inventors have found that a liquid crystal aligning agent containing a specific component is effective in achieving the above object, and have thus completed the present invention. The present invention is summarized as follows. A first repeating unit (a1) selected from the group consisting of a repeating unit represented by the following formula (1) and an imidized structure of the repeating unit represented by the above formula (1), A liquid crystal aligning agent containing a polymer component having a repeating unit represented by the following formula (2) and a second repeating unit (a2) selected from the group consisting of imidized structures of the repeating unit represented by the above formula (2): [ka] (X1 and X2 represent a tetravalent organic group. Y1 represents a divalent organic group having a structure represented by the following formula (S). Y2 represents a divalent organic group having a partial structure represented by the following formula (2c). Two R1s and R2s each independently represent a hydrogen atom or a monovalent organic group. Two Z1s and Z2s each independently represent a hydrogen atom or a monovalent organic group.) [ka] (X is a single bond, -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -COO-, -OCO- or -((CH2) a1 -A1) m1 - (a1 is an integer of 1 to 15, A1 represents an oxygen atom or -COO-, and m1 is an integer of 1 to 2. When m1 is 2, a plurality of a1's and A1's each independently have the same definition as above.) J represents a monovalent organic group having at least one group selected from the group consisting of alicyclic hydrocarbon groups having 4 to 40 carbon atoms and aromatic hydrocarbon groups having 6 to 40 carbon atoms, provided that at least one hydrogen atom possessed by the alicyclic hydrocarbon group and aromatic hydrocarbon group is substituted with a substituent selected from the group consisting of a halogen atom, a halogen atom-containing alkyl group, a halogen atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group in which a carbon-carbon bond possessed by any methylene group of the halogen atom-containing alkyl group, halogen atom-containing alkoxy group, alkyl group, alkoxy group, and alkenyl group is interrupted by an oxygen atom. * represents a bond.) [ka] (Any hydrogen atom on the benzene ring may be substituted with a monovalent substituent. * represents a bond.) [Effects of the Invention]

[0009] According to the present invention, a liquid crystal alignment film is provided which has a high refractive index, high light transmittance, rapid relaxation of accumulated charges, and excellent afterimage characteristics, and also a liquid crystal alignment agent for obtaining the liquid crystal alignment film, and a liquid crystal display element using the liquid crystal alignment film can be provided. Although the mechanism by which the above-mentioned effects of the present invention are obtained is not entirely clear, the following is thought to be one of the reasons. That is, by using a liquid crystal aligning agent containing the above-mentioned polymer, the packing property is improved due to hydrogen bonding of the urea group, so that the accumulated charge is quickly relaxed and a liquid crystal alignment film with excellent afterimage properties is obtained. Furthermore, since the film density is increased, a liquid crystal alignment film with a high refractive index and high light transmittance is obtained. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the liquid crystal alignment agent of the present invention, the liquid crystal alignment film formed using the liquid crystal alignment agent, and the liquid crystal display element having the liquid crystal alignment film will be described in detail. However, the explanation of the constituent elements described below is an example of one embodiment of the present invention, and the present invention is not limited to these contents. Each component contained in the liquid crystal aligning agent of the present disclosure and other components that may be optionally blended as needed will be described. In this specification, examples of halogen atoms include fluorine, chlorine, bromine and iodine atoms. * represents a bond unless otherwise specified.

[0011] <Polymer component> The liquid crystal aligning agent of the present invention comprises a first repeating unit (a1) selected from the group consisting of repeating units represented by the above formula (1) and imidized structures of repeating units represented by the above formula (1); It contains a polymer component having a repeating unit represented by the above formula (2) and a second repeating unit (a2) selected from the group consisting of imidized structures of the repeating unit represented by the above formula (2). The imidized structure of the repeating unit represented by the above formula (1) can be obtained by ring-closing (imidizing) the repeating unit represented by the above formula (1). In this imidized structure, the ring-closure rate of the amic acid group does not necessarily need to be 100%, and can be adjusted as desired depending on the application and purpose. The same applies to the imidized structure of the repeating unit represented by the above formula (2).

[0012] Specific examples of the polymer component include (i) at least one polymer (hereinafter also referred to as a copolymer) selected from the group consisting of polyimide precursors having the first repeating unit (a1) and the second repeating unit (a2) in the same molecule and polyimides having the imidized structure thereof, and (ii) a mixture (hereinafter also referred to as a polymer blend) of at least one polymer (P-a1) selected from the group consisting of polyimide precursors having the first repeating unit (a1) and polyimides having the imidized structure thereof and at least one polymer (P-a2) selected from the group consisting of polyimide precursors having the second repeating unit (a2) and polyimides having the imidized structure thereof. The copolymers or polymer blends may be used alone or in combination.

[0013] When the polymer component is the copolymer, the total of the first repeating unit (a1) and the second repeating unit (a2) is preferably 5 to 100 mol %, more preferably 10 to 100 mol %, of all repeating units constituting the copolymer. The content of the repeating unit (a1) is preferably 1 to 90 mol %, more preferably 1 to 85 mol %, of all repeating units constituting the copolymer.

[0014] When the polymer component is the polymer blend, the content of the repeating unit (a1) is preferably from 1 mol% to 99 mol% of all repeating units constituting the polymer (P-a1), from the viewpoint of enhancing liquid crystal alignment, more preferably from 2 mol% to 95 mol%, and even more preferably from 5 mol% to 90 mol%. Furthermore, from the viewpoint of efficiently obtaining the effects of the present invention, the content of the repeating unit (a2) is preferably 5 mol % or more and 90 mol % or less, and more preferably 10 mol % or more and 80 mol % or less, of all the repeating units constituting the polymer (P-a2).

[0015] The mass ratio of the content of the polymer (P-a2) to the content of the polymer (P-a1) is preferably 5 / 95 to 95 / 5, and more preferably 10 / 90 to 90 / 10.

[0016] (First repeating unit (a1)) In the above formula (1), Y1 represents a divalent organic group having the structure represented by the above formula (S).

[0017] Examples of the alicyclic hydrocarbon group having 4 to 40 carbon atoms in the above formula (S) include monocyclic alicyclic hydrocarbon groups such as cyclobutane, cyclopentane, cyclohexane, and cyclodecane; and fused polycyclic alicyclic hydrocarbon groups in which two or more monocyclic alicyclic hydrocarbon groups are fused together, such as norbornene, adamantane, and a steroid skeleton. The steroid skeleton has a cyclopentano-perhydrophenanthrene nucleus as its basic skeleton, and the aliphatic ring of the nucleus may have a double bond or a substituent. Examples of substituents that the alicyclic hydrocarbon group may have include a substituent selected from the group consisting of a halogen atom, a halogen atom-containing alkyl group, a halogen atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and the halogen atom-containing alkyl group, halogen atom-containing alkoxy group, and a heteroatom-containing group in which a carbon-carbon bond of any methylene group in the alkyl group, alkoxy group, and alkenyl group is interrupted by an oxygen atom. However, the alicyclic hydrocarbon group may also have a substituent other than these substituents (such as an alkyl group having 1 to 2 carbon atoms, an alkoxy group having 1 to 2 carbon atoms, a hydroxy group, a cyano group, a vinyl group, or a methoxymethyl group). As the halogen atom, a fluorine atom is preferred, and as the fluorine atom-containing alkyl group, a trifluoromethyl group is preferred.

[0018] Examples of the aromatic hydrocarbon group having 6 to 40 carbon atoms in the formula (S) include monocyclic aromatic hydrocarbon groups such as benzene; and fused polycyclic aromatic hydrocarbon groups formed by condensing two or more monocyclic aromatic hydrocarbon groups, such as naphthalene and anthracene. Substituents that the aromatic hydrocarbon group may have include a halogen atom, a halogen-containing alkyl group, a halogen-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group in which a carbon-carbon bond in any methylene group of the halogen-containing alkyl group, halogen-containing alkoxy group, alkyl group, alkoxy group, and alkenyl group is interrupted by an oxygen atom. The aromatic hydrocarbon group may also have a substituent other than these substituents (e.g., an alkyl group having 1 to 2 carbon atoms, an alkoxy group having 1 to 2 carbon atoms, a hydroxy group, a cyano group, a vinyl group, or a methoxymethyl group). A fluorine atom is preferred as the halogen atom, and a trifluoromethyl group is preferred as the fluorine-containing alkyl group.

[0019] When the formula (S) is a monovalent organic group having two or more groups of at least one type selected from the group consisting of alicyclic hydrocarbon groups having 4 to 40 carbon atoms and aromatic hydrocarbon groups having 6 to 40 carbon atoms, it is sufficient that at least one of the alicyclic hydrocarbon groups or aromatic hydrocarbon groups has a substituent exemplified above (i.e., a substituent selected from the group consisting of a halogen atom, a halogen-atom-containing alkyl group, a halogen-atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group in which a carbon-carbon bond of any methylene group in the halogen-atom-containing alkyl group, halogen-atom-containing alkoxy group, alkyl group, alkoxy group, and alkenyl group is interrupted by an oxygen atom), and the other alicyclic hydrocarbon groups or aromatic hydrocarbon groups in the formula (S) may be unsubstituted or may have a substituent other than the above-exemplified substituents.

[0020] More preferred specific examples of the structure represented by the above formula (S) include structures represented by any of the following formulas (S1) to (S2). [ka] (X 1 is a single bond, -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -COO-, -OCO- or -((CH2) a1 -A1) m1 - (a1 is an integer of 1 to 15, A1 represents an oxygen atom or -COO-, and m1 is an integer of 1 to 2. When m1 is 2, a plurality of a1s and A1s each independently have the above definition). G 1 represents a divalent cyclic group selected from a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms and a divalent alicyclic hydrocarbon group having 4 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine atom-containing alkyl group having 1 to 3 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. m is an integer of 1 to 4. When m is 2 or more, a plurality of X 1 , G 1 are each independently defined above. R 1 represents a fluorine atom, a fluorine atom-containing alkyl group having 1 to 10 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 10 carbon atoms, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, or an alkoxyalkyl group having 3 to 10 carbon atoms. [ka] (X 2 represents -CONH-, -NHCO-, -O-, -CHO-, -OCH-, -COO- or -OCO-. 2represents a structure having a steroid skeleton, wherein at least one hydrogen atom of the structure having a steroid skeleton is substituted with a substituent selected from the group consisting of a halogen atom, a halogen-atom-containing alkyl group, a halogen-atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group in which a carbon-carbon bond of any methylene group of the halogen-atom-containing alkyl group, halogen-atom-containing alkoxy group, alkyl group, alkoxy group, and alkenyl group is interrupted with an oxygen atom.

[0021] In the above formula (S1), G 1 Examples of the divalent cyclic group in the formula (I) include a cyclopropylene group, a cyclohexylene group, and a phenylene group. Any hydrogen atom on these cyclic groups may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine atom-containing alkyl group having 1 to 3 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom.

[0022] In the above formula (S2), G 2 Examples of the structure having a steroid skeleton in the formula (I) include a structure containing a cholestanyl group, a cholesteryl group, or a lanostaniyl group.

[0023] Preferred embodiments of formula (S1) include the following formulae (S1-x1) to (S1-x7). [ka]

[0024] In the above formula, X p is -(CH2) a A1 is an oxygen atom or -COO-* (wherein the bond marked with "*" is (CH2)), -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CHO-, -CHOCO-, -COO-, or -OCO-. a2 A2 is an oxygen atom or *-COO- (where the bond marked with "*" is (CH2)a2 a3 is 0 or 1, a1 and a2 are each independently an integer of 1 to 10, and Cy is a 1,4-cyclohexylene group or a 1,4-phenylene group. 1 represents a fluorine atom, a fluorine atom-containing alkyl group having 1 to 10 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 10 carbon atoms, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, or an alkoxyalkyl group having 3 to 10 carbon atoms.

[0025] A preferred embodiment of the above formula (S2) is the following formula (S2-x). In formula (S2-x), X represents formula (X1), (X2), or (X3), Col represents formula (Col1), (Col2), or (Col3), and G represents formula (G1), (G2), (G3), or (G4). Me represents a methyl group. [ka]

[0026] Specific examples of the divalent organic group having the structure represented by the above formula (S) include a divalent organic group derived from an aromatic diamine (d) having the structure represented by the above formula (S) in its side chain. The divalent organic group having the structure represented by the above formula (S) is preferably a group obtained by removing two amino groups from the above aromatic diamine (d).

[0027] The aromatic diamine (d) preferably has at least one benzene ring. Specific examples of the aromatic diamine (d) include diamines represented by the following formula (d1) or formula (d2). [ka] (X is a single bond, -O-, -C(CH3)2-, -NH-, -CO-, -(CH2) m -, -SO2-, -O-(CH2) m -O-, -OC(CH3)2-, -CO-(CH2) m -, -NH-(CH2) m-, -SO2-(CH2) m -, -CONH-(CH2) m -, -CONH-(CH2) m -NHCO- or -COO-(CH2) m represents a divalent organic group of -OCO-. m is an integer of 1 to 8. Y represents a structure represented by the above formula (S). In the above formula (d2), the two Ys may be the same or different.

[0028] Preferred examples of the diamine represented by the above formula (d1) include the following formulas (d1-1) to (d1-6): Preferred examples of the diamine represented by the above formula (d2) include the following formulas (d2-1) to (d2-6): [ka] [ka] (X v1 ~X v4 , X p1 ~X p8 are each independently -(CH2) a - (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CHO-, -CH2-OCO-, -COO-, or -OCO-; X V5 ~X V6 , X s1 ~X s4 each independently represents -O-, -CHO-, -COO- or -OCO-. a ~X f is a single bond, -O-, -NH-, or -O-(CH2) m -O- (m represents an integer of 1 to 8), and R v1 ~R v4 , R 1a ~R 1h are each independently, -C n H 2n+1 (n represents an integer of 3 to 10), or -OC n H 2n+1 (n represents an integer of 3 to 10.)

[0029] In the above formula (1), X1 represents a tetravalent organic group. Examples of the tetravalent organic group include a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or a derivative thereof, a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride or a derivative thereof, and a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride or a derivative thereof. A preferred example is a tetravalent organic group derived from a tetracarboxylic dianhydride or a derivative thereof represented by the following formula (T): The aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to an aromatic ring. Acyclic aliphatic tetracarboxylic acid dianhydrides are acid dianhydrides obtained by intramolecular dehydration of four carboxy groups bonded to a chain hydrocarbon structure. However, they do not necessarily have to be composed of chain hydrocarbon structures only, and may also contain an alicyclic structure or an aromatic ring structure. Alicyclic tetracarboxylic acid dianhydrides are acid dianhydrides obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to an alicyclic structure. However, none of these four carboxy groups are bonded to an aromatic ring. Furthermore, they do not necessarily have to be composed solely of an alicyclic structure; they may also contain a chain hydrocarbon structure or an aromatic ring structure. [ka] (X represents a structure selected from any of the following formulas (x-1) to (x-13).) [ka] (R 1 ~R 4 R each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. 5 and R 6each independently represents a hydrogen atom or a methyl group. j and k are integers of 0 or 1, and A1 and A2 each independently represent a single bond, -O-, -CO-, -COO-, phenylene, a sulfonyl group, or an amide group. *1 is a bond bonded to one acid anhydride group, and *2 is a bond bonded to the other acid anhydride group. In the above formula (x-13), the two A2 may be the same or different.

[0030] More preferred specific examples of the above formula (x-1) include the following formulae (X1-1) to (X1-6).

[0031] [ka]

[0032] Preferred specific examples of the above formulae (x-12) and (x-13) include the following formulae (x-14) to (x-29). [ka] [ka]

[0033] Preferred examples of the tetracarboxylic dianhydride represented by the above formula (T) or a derivative thereof include tetracarboxylic dianhydrides represented by formula (3) in which X is any of the formulae (x-1) to (x-7) and (x-11) to (x-13) or a derivative thereof.

[0034] In the above formula (1), two R1s each independently represent a hydrogen atom or a monovalent organic group. Examples of the monovalent organic group include a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Two R1s each independently preferably represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. In the above formula (1), two Z1 each independently represent a hydrogen atom or a monovalent organic group. Examples of the monovalent organic group include a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted alkenyl group having 2 to 10 carbon atoms, an optionally substituted alkynyl group having 2 to 10 carbon atoms, a tert-butoxycarbonyl group, and a 9-fluorenylmethoxycarbonyl group. Two Z1 each independently preferably represent a hydrogen atom or a methyl group. In the above formula (1), X1, Y1, R1, and Z1 may each be one type or two or more types.

[0035] (Second repeating unit (a2)) In the above formula (2), Y2 represents a divalent organic group having a partial structure represented by the following formula (2c). Examples of the divalent organic group include divalent organic groups obtained by removing two amino groups from a diamine having a partial structure represented by the following formula (2c). Y2 may have the partial structure represented by the following formula (2c) in either the main chain direction or the side chain direction. Y2 may have one, two, or three or more partial structures represented by the following formula (2c). Y2 preferably has one or two partial structures represented by the following formula (2c) in the main chain direction, and more preferably has one partial structure represented by the following formula (2c) in the main chain direction. Y2 is even more preferably a divalent organic group represented by the following formula (2c).

[0036] [ka] (Any hydrogen atom on the benzene ring may be substituted with a monovalent substituent.)

[0037] Examples of the monovalent substituent on the benzene ring include a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkenyl group having 2 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, a carboxyl group, an alkyloxycarbonyl group having 1 to 10 carbon atoms, a cyano group, and a nitro group.

[0038] From the viewpoint of efficiently achieving the effects of the present invention, preferred specific examples of the divalent organic group represented by the above formula (2c) include, but are not limited to, divalent organic groups represented by the following formulas (2c-1) to (2c-3): [ka] (Any hydrogen atom on the benzene ring may be substituted with a monovalent substituent. Examples of the monovalent substituent include the structures exemplified as the substituent for any hydrogen atom on the benzene ring in the above formula (2c).)

[0039] Specific examples of the monovalent substituent in the above formulae (2c-1) to (2c-3) include the structures exemplified as the monovalent substituent in the above formula (2c).

[0040] X2 in the above formula (2) may be the same as X1 in the above formula (1). Examples of R2 in the above formula (2) include the same as R1 in the above formula (1). Z2 in the above formula (2) may be the same as Z1 in the above formula (1). In the above formula (2), X2, Y2, R2, and Z2 may each be one type or two or more types.

[0041] (Third repeating unit) The polymer component may further have a third repeating unit (a3) ​​selected from the group consisting of a repeating unit represented by the following formula (3) and an imidized structure of the repeating unit represented by the following formula (3). [ka] (X3 represents a tetravalent organic group. Y3 represents a divalent organic group other than a divalent organic group having a structure represented by the above formula (S) and a divalent organic group having a partial structure represented by the above formula (2c). Each R3 independently represents a hydrogen atom or a monovalent organic group. Each Z3 independently represents a hydrogen atom or a monovalent organic group.)

[0042] Specific embodiments of the polymer component further having the third repeating unit (a3) ​​include copolymers and polymer blends. Examples of the copolymer include at least one polymer selected from the group consisting of polyimide precursors having the first repeating unit (a1), the second repeating unit (a2), and the third repeating unit (a3) ​​in the same molecule, and polyimides having the imidized structure thereof. An example of the polymer blend is a mixture of at least one polymer (P-a1+a2) selected from the group consisting of polyimide precursors having the first repeating unit (a1) and the second repeating unit (a2) in the same molecule and polyimides having the imidized structure thereof, and at least one polymer (P-a1+a3) selected from the group consisting of polyimide precursors having the first repeating unit (a1) and the third repeating unit (a3) ​​in the same molecule and polyimides having the imidized structure thereof. The polymer (P-a1+a3) does not necessarily have to have the second repeating unit (a2). The copolymers or polymer blends may be used alone or in combination.

[0043] When the polymer component is the above copolymer, the content of the repeating unit (a3) ​​is preferably 5 to 90 mol %, more preferably 10 to 80 mol %, of all repeating units constituting the copolymer. In this case, the total of the first repeating unit (a1) and the second repeating unit (a2) is preferably 10 to 95 mol %, more preferably 20 to 90 mol %, of all repeating units constituting the copolymer.

[0044] When the polymer component is the above-mentioned polymer blend, the mass ratio of the content of the above-mentioned polymer (P-a1+a3) to the content of the above-mentioned polymer (P-a1+a2) is preferably 5 / 95 to 95 / 5, and more preferably 10 / 90 to 90 / 10.

[0045] Specific examples of the divalent organic group of Y3 include, but are not limited to, organic groups obtained by removing two amino groups from the following diamines (hereinafter also referred to as other diamines):

[0046] p-phenylenediamine, m-phenylenediamine, 4-(2-(methylamino)ethyl)aniline, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, and diamines having a carboxyl group such as the diamine compounds represented by the following formulas (3b-1) to (3b-4), diamines having a photoalignment group such as the diamines represented by the following formulas (g-1) to (g-6), 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, and 3,3'-diaminodiphenyl ether , 1,2-bis(4-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,2-bis(4-aminophenoxy)ethane, 1,2-bis(4-amino-2-methylphenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy) xanthane, 4-(2-(4-aminophenoxy)ethoxy)-3-fluoroaniline, di(2-(4-aminophenoxy)ethyl)ether, 4-amino-4'-(2-(4-aminophenoxy)ethoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 2,2'-bis[4- (4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2'-bis(4-aminophenyl)propane, diamines represented by the following formulas (nh-1) to (nh-8), dodecanoxy-2,4-diaminobenzene, tetradecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy-2,4-diaminobenzene, dodecanoxy-2,5-diaminobenzene, tetradecanoxy-2,5-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indan-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-6-amine, 1,3-bis(4-aminophenethyl)urea, diamines having a photopolymerizable group at the terminal such as those of the following formulas (4b-1) to (4b-12), radical-opening diamines such as those of the following formulas (R1) to (R5), diamines having a photosensitizing function that exhibits a sensitizing effect upon irradiation with light, such as 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, and 9,9-bis(4-aminophenyl)fluorene; 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, 9-methyl-3,6-diaminocarbazole, 9-ethyl-3,6-diaminocarbazole, and 9-phenyl-3,6-diaminocarbazole; diamines having a heterocycle, such as those represented by the following formulas (z-1) to (z-20): amines, diamines having a diphenylamine skeleton such as those of the following formulae (Dp-1) to (Dp-9), diamines having a group "-N(D)-" (D represents a protecting group which is eliminated by heating and replaced with a hydrogen atom. D is preferably a tert-butoxycarbonyl group) or a group "*-LOD" (* represents a bond to the nitrogen atom. L represents an alkylene group having 1 to 5 carbon atoms. D represents a protecting group which is eliminated by heating and replaced with a hydrogen atom. D is preferably a tert-butoxycarbonyl group) such as those of the following formulae (5-1) to (5-13), 1,3-bis(3-aminophenyl)-2-(2-phenylpropanol ... diamines such as (2-aminopropyl)-tetramethyldisiloxane, diamines having a siloxane bond such as diamines represented by the following formula (Ds-1), diamines having an oxazoline structure such as diamines represented by the following formulas (Ox-1) to (Ox-2), aliphatic diamines such as 1,1-meta-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, and hexamethylenediamine; and alicyclic diamines such as 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and 1,3-bis(aminomethyl)cyclohexane. [ka] (In (3b-1) above, A 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-; m1 and m2 each independently represent an integer of 0 to 4, and m1 + m2 represents an integer of 1 to 4. In formula (3b-2), m3 and m4 each independently represent an integer of 1 to 5. In formula (3b-3), A 2 represents a linear or branched alkyl group having 1 to 5 carbon atoms, and m5 represents an integer of 1 to 5. In formula (3b-4), A 3 and A 4 each 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-, and m6 represents an integer of 1 to 4. [ka] (In formula (g-6), L represents a single bond, an alkylene group having 1 to 15 carbon atoms, or a divalent organic group having -O-, -COO-, -NH-, -NHCO-, or -CON(CH3)- inserted between the carbon-carbon bonds of the alkylene group or at least one of the terminals of the alkylene group. However, the divalent organic group is bonded to the oxygen atom of the ester bond through a carbon atom. X 1 , G 1 , R 1 has the same meaning as (S1) above. m is an integer of 0 to 4. When m is 2 or more, a plurality of X 1 , G 1are each independently defined as above. In addition, a hydrogen atom on the benzene ring may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine atom-containing alkyl group having 1 to 3 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. [ka] [ka] (In formulas (4b-1) to (4b-6), n1 is an integer of 2 to 12.) [ka] (In formulas (4b-7) to (4b-12), n2 is an integer from 0 to 12, and n3 is an integer from 2 to 12.) [ka] (In formulas (R3) to (R5), n is an integer of 1 to 6.) [ka] [ka] [ka] [ka] (In formulas (5-1) to (5-13), Boc represents a tert-butoxycarbonyl group.) [ka] [ka]

[0047] The above 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, diamines having a photopolymerizable group at the terminal, diamines represented by the above formulae (R1) to (R5), and diamines represented by the above formulae (z-1) to (z-20) may be used singly or in combination when producing the polymer component, in order to increase the response speed of liquid crystal display elements using the PSA system or SC-PVA mode.

[0048] Among the above, from the viewpoint of suitably obtaining the effects of the present invention, the other diamines preferably include p-phenylenediamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 2,2'-dimethyl-4,4'-diaminobiphenyl, diamines represented by the above formulae (4b-1) to (4b-12), diamines represented by the above formulae (R1) to (R5), diamines represented by the above formulae (z-1) to (z-20), diamines represented by the above formulae (Dp-1) to (Dp-9), and diamines represented by the above formulae (Ox-1) to (Ox-2).

[0049] X3 in the above formula (3) may be the same as X1 in the above formula (1). Examples of R3 in the above formula (3) include the same as R1 in the above formula (1). Z3 in the above formula (3) may be the same as Z1 in the above formula (1). In the above formula (3), X3, Y3, R3, and Z3 may each be one type or two or more types.

[0050] <Method of producing polymer> Examples of the polyimide precursor used in the present invention include polyamic acid, polyamic acid ester, etc. The polyimide precursor used in the present invention can be synthesized by a known method such as that described in WO 2013 / 157586.

[0051] More specifically, this is achieved by reacting a diamine component with a tetracarboxylic acid derivative component in a solvent (condensation polymerization). Examples of the tetracarboxylic acid derivative component include tetracarboxylic acid dianhydrides and their derivatives (tetracarboxylic acid dihalides, tetracarboxylic acid diesters, or tetracarboxylic acid diester dihalides). When a polymer contains an amic acid structure (e.g., when R1 and R2 are hydrogen atoms in the above formula (1) or (2)), a polymer having an amic acid structure (polyamic acid) can be obtained by reacting a tetracarboxylic acid derivative component with a diamine component. The solvent is not particularly limited as long as it dissolves the resulting polymer. Specific examples of the solvent include cyclohexanone, cyclopentanone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolidinone. When the polymer has high solubility in the solvent, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or solvents represented by the following formulas [D-1] to [D-3] can be used. [ka] (In formula [D-1], D 1 represents an alkyl group having 1 to 3 carbon atoms, and in formula [D-2], D 2 represents an alkyl group having 1 to 3 carbon atoms, and in formula [D-3], D 3 represents an alkyl group having 1 to 4 carbon atoms.

[0052] Specific examples of the solvents represented by the above formulas [D-1] to [D-3] include propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether.

[0053] These solvents may be used alone or in combination. Furthermore, even if a solvent does not dissolve the polymer, it may be mixed with the above-mentioned solvent to the extent that the produced polymer does not precipitate. When the diamine component and the tetracarboxylic acid derivative component are reacted in a solvent, the reaction can be carried out at any concentration, preferably 1 to 50 mass %, more preferably 5 to 30 mass %. The reaction can be carried out at a high concentration in the early stage, and then additional solvent can be added. In the reaction, the ratio of the total number of moles of the diamine components to the total number of moles of the tetracarboxylic acid derivative components is preferably 0.8 to 1.2. As in a typical condensation polymerization reaction, the closer this molar ratio is to 1.0, the higher the molecular weight of the polymer produced.

[0054] The polyamic acid ester can be obtained by known methods such as [I] a method of reacting the polyamic acid obtained by the above method with an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester with a diamine, or [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine.

[0055] Furthermore, polyimides can be obtained by ring-closing (imidizing) the polyimide precursor. In this polyimide, the ring-closure rate of amic acid groups (also referred to as the imidization rate) does not necessarily need to be 100% and can be adjusted as desired depending on the application and purpose. In this specification, the imidization rate refers to the proportion of imide groups in the total amount of imide groups derived from tetracarboxylic dianhydride or its derivatives and carboxyl groups (or their derivatives).

[0056] Methods for imidizing the polyimide precursor include thermal imidization, in which a solution of the polyimide precursor is heated as is, and catalytic imidization, in which a catalyst is added to a solution of the polyimide precursor.

[0057] When the polyimide precursor is thermally imidized in a solution, the temperature is preferably 100 to 400° C., more preferably 120 to 250° C., and it is preferable to carry out the imidization while removing water produced by the imidization reaction from the system.

[0058] Catalytic imidization of a polyimide precursor can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring the mixture at preferably -20 to 250°C, more preferably 0 to 180°C. The amount of the basic catalyst is preferably 0.5 to 30 times, more preferably 2 to 20 times, the molar ratio of the amic acid groups, and the amount of the acid anhydride is preferably 1 to 50 times, more preferably 3 to 30 times, the molar ratio of the amic acid groups. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Of these, pyridine is preferred because it has adequate basicity for promoting the reaction. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Of these, acetic anhydride is preferred because it facilitates purification after the reaction. The imidization rate by catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[0059] To recover the resulting polyimide precursor or polyimide from a reaction solution of the polyimide precursor or polyimide, the reaction solution may be precipitated by pouring the reaction solution into a solvent. Examples of solvents used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer precipitated by pouring into the solvent can be recovered by filtration and then dried at room temperature or by heating under atmospheric or reduced pressure. Furthermore, the precipitated polymer can be redissolved in an organic solvent and reprecipitated and recovered 2 to 10 times to reduce the amount of impurities in the polymer. Examples of solvents used in this process include alcohols, ketones, and hydrocarbons. Using three or more solvents selected from these solvents is preferred because it further increases the efficiency of purification.

[0060] The molecular weight of the polymer used in the present invention is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000, in terms of weight average molecular weight measured by GPC (Gel Permeation Chromatography), taking into consideration the strength of the liquid crystal alignment film obtained therefrom, workability during film formation, and coating properties.

[0061] <End-capping agent> In synthesizing the polymer of the present invention, an end-capping polymer may be synthesized using a suitable end-capping agent together with the tetracarboxylic dianhydride or its derivative and the diamine component as described above. The end-capping polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by coating and improving the adhesion properties between the sealant and the liquid crystal alignment film. Examples of the terminal of the polymer in the present invention include an amino group, a carboxyl group, an acid anhydride group, or a derivative thereof. The amino group, carboxyl group, acid anhydride group, and isocyanate group can be obtained by a conventional condensation reaction or by blocking the terminal with the following terminal blocking agents, and the derivatives can be obtained in the same manner, for example, by using the following terminal blocking agents.

[0062] Examples of the end-capping agent include acid anhydrides such as acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, and 4-ethynylphthalic anhydride; dicarbonate diester compounds such as di-tert-butyl dicarbonate and diallyl dicarbonate; acryloyl chloride, methacryloyl chloride, and nicotinic acid chloride. chlorocarbonyl compounds such as those listed above; monoamine compounds such as aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; and monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, and those having structures represented by the following formulas [1a] to [1d]. [ka] (X 3 represents an alkylene group having 1 to 5 carbon atoms, a benzene ring, or a cyclohexane ring; X 4 represents an alkylene group having 1 to 5 carbon atoms, a benzene ring, or a cyclohexane ring. [ka] (X 5 represents an alkylene group having 1 to 5 carbon atoms, a benzene ring, or a cyclohexane ring; X 6 represents an alkylene group having 1 to 5 carbon atoms, a benzene ring, or a cyclohexane ring.

[0063] The proportion of the end-capping agent used is preferably 0.01 to 20 parts by mole, and more preferably 0.01 to 10 parts by mole, per 100 parts by mole of the total of the diamine components used.

[0064] The blending ratio of the polymer components used in the manufacturing method of the liquid crystal alignment film of the present invention is not particularly limited, but for example, the total amount of the polymer components contained in the liquid crystal alignment agent is 0.1 to 30 mass %, preferably 3 to 10 mass %.

[0065] The liquid crystal aligning agent used for producing the liquid crystal alignment film may contain other polymers in addition to the polymer components. In this case, the content of the other polymers is 0.5% by mass to 15% by mass, preferably 1% by mass to 10% by mass, of the total amount of the polymer components. Examples of other polymers include polyimide precursors other than the polymer components, polyimides, acrylic polymers, methacrylic polymers, polystyrene, polyamides, and polysiloxanes.

[0066] The solvent contained in the liquid crystal aligning agent is not particularly limited as long as it can dissolve the polymer, and examples thereof include lactone solvents such as γ-valerolactone and γ-butyrolactone; γ-butyrolactam, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n- Lactam solvents such as N,N-pentyl-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone; amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, 3-methoxy-N,N-dimethylpropanamide, and 3-butoxy-N,N-dimethylpropanamide;Cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, 2,6-dimethyl-4-heptanone (diisobutyl ketone), methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether Examples of suitable solvents include ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monobutyl ether, propylene glycol diacetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, isoamyl propionate, isoamyl isobutyrate, diisopropyl ether, and diisopentyl ether; carbonate solvents such as ethylene carbonate and propylene carbonate, 1-hexanol, cyclohexanol, 1,2-ethanediol, and 2,6-dimethyl-4-heptanol (diisobutylcarbinol). These may be used alone or in combination of two or more.

[0067] Preferred solvent combinations 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 monobutyl ether. Lithium diethyl ether, N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, and 4-hydroxy-4-methyl-2-pentanone, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and 2,6-dimethyl-4-heptanone, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol monobutyl ether ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol diacetate, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and 2,6-dimethyl-4-heptanone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol diacetate, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and 2,6-dimethyl-4-heptanone, N-methyl Examples of suitable solvents include 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. The type and content of such solvents are appropriately selected depending on the coating device, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

[0068] <Liquid crystal alignment agent> The liquid crystal aligning agent of the present invention may contain other components other than those described above, such as a crosslinkable compound, a functional silane compound, a surfactant, a compound having a polymerizable group, etc., as needed.

[0069] The crosslinkable compound can be used for the purpose of increasing the strength of the liquid crystal alignment film. Examples of such crosslinkable compounds include at least one compound selected from the group consisting of a compound having two or more of at least one type of group selected from the group consisting of an epoxy group, an isocyanate group, an oxetane ring, an oxazoline ring, and a cyclocarbonate group, a compound having two or more of at least one type of group selected from the group consisting of a hydroxy group, a hydroxyalkyl group, and a lower alkoxyalkyl group, and a compound having a blocked isocyanate group.

[0070] Examples of compounds having an epoxy group include bisphenol A type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, alicyclic epoxy resins, glycidyl ester type epoxy resins, glycidyl diamine type epoxy resins, heterocyclic epoxy resins, acrylic resins having an epoxy group, etc. Examples of commercially available products of these include Epolite 400E and 3002 (manufactured by Kyoeisha Chemical Co., Ltd.), Epicoat 828 and 152, and Epoxy Novolac 180S (manufactured by Japan Epoxy Resins Co., Ltd.). Among these, glycidyldiamine-based epoxy resins are preferred, and the following formula (b E ) [ka] (Formula(b E In the formula, R is a divalent organic group having an aromatic ring or a cyclohexane ring and having 6 to 40 carbon atoms. The compound represented by the formula is more preferred. The above formula (b E Specific examples of the compound represented by the following formula (b E -1)~(b E -6) [ka]

[0071] Specific examples of compounds having two or more oxetane rings include 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene (Aronoxetane OXT-121 (XDO)), di[2-(3-oxetanyl)butyl]ether (Aronoxetane OXT-221 (DOX)), 1,4-bis[(3-ethyloxetan-3-yl)methoxy]benzene (HQOX), 1,3-bis[(3-ethyloxetan-3-yl)methox] bis[(3-ethyloxetan-3-yl)methoxy]benzene (RSOX), 1,2-bis[(3-ethyloxetan-3-yl)methoxy]benzene (CTOX), 4,4'-bis[(3-ethyloxetan-3-yl)methoxy]biphenyl (4,4'-BPOX), 2,2'-bis[(3-ethyl-3-oxetanyl)methoxy]biphenyl (2,2'-BPOX), 3,3',5,5'-tetramethyl[4,4'-bis(3-ethyloxetan-3-yl)methoxy]biphenyl ( TM-BPOX), 2,7-bis[(3-ethyloxetan-3-yl)methoxy]naphthalene (2,7-NpDOX), 1,6-bis[(3-ethyloxetan-3-yl)methoxy]-2,2,3,3,4,4,5,5-octafluorohexane (OFH-DOX), 2,4,6-O-tris[(3-ethyloxetan-3-yl)methyl]cyanuric acid, bisphenol A and 3-ethyl-3-chloromethyloxetane (abbreviated as OXC). Examples include etherified compounds (BisAOX), etherified compounds of bisphenol F and OXC (BisFOX), etherified compounds of phenol novolac and OXC (PNOX), etherified compounds of cresol novolac and OXC (CNOX), oxetanylsilsesquioxane (OX-SQ), silicon alkoxide of 3-ethyl-3-hydroxymethyloxetane (OX-SC) (the names in parentheses are trade names or developed product names, manufactured by Toagosei Co., Ltd.), ETARNACOLL OXBP (manufactured by Ube Industries, Ltd.), and compounds represented by the following formula (C). Among these, Aronoxetane, OX-SC, OXT-121, OXT-221, and PNOX-1009 (all manufactured by Toagosei Co., Ltd.) and ETARNACOLL OXBP (manufactured by Ube Industries, Ltd.) are preferred, with OX-SC, OXT-121, OXT-221, and PNOX-1009 being particularly preferred. [ka]

[0072] Specific examples of compounds having two or more oxazoline rings include 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), 2,2'-bis(5-methyl-2-oxazoline), 2,2'-bis(5,5'-dimethyloxazoline), 2,2'-bis(4,4,4',4'-tetramethyl-2-oxazoline), 1,2-bis(2-oxazolin-2-yl)ethane, 1,4-bis(2-oxazolin-2-yl)butane, 1,6-bis(2-oxazoline), 1,4-bis(2-oxazolin-2-yl)hexane, 1,8-bis(2-oxazolin-2-yl), 1,4-bis(2-oxazolin-2-yl)cyclohexane, 1,2-bis(2-oxazolin-2-yl)benzene, 1,3-bis(2-oxazolin-2-yl)benzene, 1,4-bis(2-oxazolin-2-yl)benzene, 1,2-bis(5-methyl-2-oxazolin-2-yl)benzene, 1,3-bis(5-methyl-2-oxazolin-2-yl)benzene, 1,4-bis(5-methyl-2-oxazolin-2-yl)benzene 1,4-bis(4,4'-dimethyl-2-oxazolin-2-yl)benzene, 1,4-bis(4,5-dihydro-2-oxazolyl)benzene, 1,3-bis(4,5-dihydro-2-oxazolyl)benzene, 2,3-bis(4-isopropenyl-2-oxazolin-2-yl)butane, 2,2'-bis(4-benzyl-2-oxazoline), 2,6-bis(isopropyl-2-oxazolin-2-yl)pyridine, 2,2'- Examples include compounds such as isopropylidenebis(4-tert-butyl-2-oxazoline), 2,2'-isopropylidenebis(4-phenyl-2-oxazoline), 2,2'-methylenebis(4-tert-butyl-2-oxazoline), and 2,2'-methylenebis(4-phenyl-2-oxazoline), 1,2,4-tris-(2-oxazolinyl-2)-benzene, and compounds such as polymers and oligomers having oxazolyl, such as EPOCROS (manufactured by Nippon Shokubai Co., Ltd.).

[0073] Blocked isocyanate compounds are commercially available, and examples that can be preferably used include Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, and Millionate MS-50 (all manufactured by Tosoh Corporation), and Takenate B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, and B-882N (all manufactured by Mitsui Chemicals, Inc.).

[0074] Examples of the compound having two or more groups of at least one type selected from the group consisting of a hydroxy group, a hydroxyalkyl group, and a lower alkoxyalkyl group include compounds represented by the following formulas (b1-1) to (b1-22). [ka] [ka] [ka]

[0075] The above are examples of the crosslinkable compound, and the present invention is not limited to these. The crosslinkable compound used in the liquid crystal aligning agent of the present invention may be one type or a combination of two or more types.

[0076] The content of the crosslinkable compound in the liquid crystal aligning agent of the present invention is 0.1 to 150 parts by mass, or 0.1 to 100 parts by mass, or 1 to 50 parts by mass, relative to 100 parts by mass of all polymer components.

[0077] The functional silane compound can be used to improve the adhesion between the liquid crystal alignment film and the base substrate. Specific examples include the silane compounds described in paragraph

[0019] of International Publication No. 2014 / 119682. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, per 100 parts by mass of all polymer components.

[0078] The surfactant can be used to improve the uniformity of the film thickness and the surface smoothness of the liquid crystal alignment film. Examples of the compound include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. Specific examples of these surfactants include those described in paragraph

[0117] of International Publication No. 2016 / 047771. The amount of surfactant used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of all polymer components contained in the liquid crystal alignment agent.

[0079] Examples of compounds having a polymerizable group include compounds having one or more polymerizable unsaturated groups such as acrylate groups or methacrylate groups in the molecule, such as compounds represented by the following formulas (M-1) to (M-7).

[0080] [ka]

[0081] Furthermore, the liquid crystal aligning agent of the present invention can contain a compound that promotes charge transfer in the liquid crystal alignment film and promotes charge dissipation in the device. The nitrogen-containing heterocyclic amine compounds represented by formulas [M1] to [M156], more preferably 3-picolylamine and 4-picolylamine, are described in paragraphs

[0194] to

[0200] of International Publication No. 2011 / 132751 (published October 27, 2011). These amine compounds may be added directly to the liquid crystal aligning agent, but are preferably added after being prepared into a solution with a concentration of 0.1 to 10% by mass, preferably 1 to 7% by mass. The solvent used is not particularly limited, as long as it dissolves the polymer.

[0082] An imidization accelerator or the like may be added to the liquid crystal aligning agent of the present invention for the purpose of efficiently promoting imidization by heating when the coating film is baked.

[0083] The solid content concentration in the liquid crystal aligning agent (the ratio of the total mass of the components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected taking into consideration viscosity, volatility, etc., but is preferably in the range of 0.5 to 15 mass%, more preferably 1 to 10 mass%. The particularly preferred range of solid content varies depending on the method used to apply the liquid crystal alignment agent to the substrate. For example, when using a spin coating method, a particularly preferred solid content range is 1.5 to 4.5 mass%. When using a printing method, a particularly preferred solid content range is 3 to 9 mass%, thereby resulting in a solution viscosity range of 12 to 50 mPa·s. When using an inkjet method, a particularly preferred solid content range is 1 to 5 mass%, thereby resulting in a solution viscosity range of 3 to 15 mPa·s.

[0084] <Liquid crystal alignment film> The liquid crystal alignment film of the present invention is obtained from the liquid crystal aligning agent. The liquid crystal alignment film of the present invention can be used as a horizontal alignment type or vertical alignment type liquid crystal alignment film, and is particularly suitable for a vertical alignment type liquid crystal display element such as a VA mode or PSA mode.

[0085] <Liquid crystal display element> The liquid crystal display element of the present invention is provided with the above-mentioned liquid crystal alignment film. The liquid crystal aligning agent of the present invention is also preferably used for a liquid crystal display element which has a liquid crystal layer between a pair of substrates each having an electrode, and is manufactured by a process of disposing a liquid crystal composition containing a polymerizable compound which is polymerized by at least one of active energy rays and heat between the pair of substrates, and polymerizing the polymerizable compound by at least one of irradiation with active energy rays and heating while applying a voltage between the electrodes.

[0086] The liquid crystal display element of the present invention can be produced, for example, by a method including the following steps (1) to (3) or steps (1) to (4). (1) A process of applying a liquid crystal alignment agent onto a substrate The liquid crystal aligning agent of the present invention is applied to one surface of a substrate having a patterned transparent conductive film by an appropriate application method such as a roll coater method, a spin coat method, a printing method, or an inkjet method. The substrate is not particularly limited as long as it is highly transparent, and plastic substrates such as acrylic substrates and polycarbonate substrates can be used in addition to glass substrates and silicon nitride substrates. In addition, in a reflective liquid crystal display element, an opaque material such as a silicon wafer can be used for only one substrate, and in this case, a light-reflecting material such as aluminum can be used for the electrode. (2) Baking the coating After applying the liquid crystal alignment agent, preliminary heating (pre-baking) is preferably performed first for the purpose of preventing dripping of the applied alignment agent. The pre-baking temperature is preferably 30 to 200°C, more preferably 40 to 150°C, and particularly preferably 40 to 100°C. The pre-baking time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Then, a heating (post-baking) step is preferably performed. The post-baking temperature is preferably 80 to 300°C, more preferably 120 to 250°C. The post-baking time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The film thickness of the film thus formed is preferably 5 to 300 nm, more preferably 10 to 200 nm.

[0087] The coating film formed in the above step (1) can be used as a liquid crystal alignment film as it is, but the coating film may also be subjected to an alignment ability imparting treatment, such as a rubbing treatment in which the coating film is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton, or a photoalignment treatment in which the coating film is irradiated with polarized or unpolarized radiation.

[0088] In the photo-alignment treatment, the radiation to be irradiated onto the coating film can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, the radiation may be irradiated from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When irradiating with unpolarized radiation, the irradiation direction is an oblique direction. (3) Forming the liquid crystal layer (3-1) VA type LCD element Two substrates on which liquid crystal alignment films are formed are prepared as described above, and liquid crystal is placed between the two substrates arranged opposite each other. Specifically, the following two methods can be used. The first method is a conventionally known method. First, the two substrates are arranged opposite each other with a gap (cell gap) between them so that the liquid crystal alignment films face each other. Next, the peripheries of the two substrates are bonded together using a sealant, and a liquid crystal composition is injected into the substrate surfaces and the cell gap defined by the sealant to contact the film surface, and then the injection hole is sealed.

[0089] The second method is called the ODF (One Drop Fill) method. A UV-curable sealant, for example, is applied to a predetermined location on one of two substrates on which a liquid crystal alignment film has been formed, and a liquid crystal composition is then dropped onto several predetermined locations on the liquid crystal alignment film. The other substrate is then attached so that the liquid crystal alignment film faces the other substrate, and the liquid crystal composition is spread over the entire surface of the substrate and brought into contact with the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. In either method, it is desirable to further heat the substrate to a temperature at which the liquid crystal composition is in an isotropic phase, and then slowly cool it to room temperature to remove flow alignment that occurs during liquid crystal filling. The liquid crystal composition is not particularly limited, and any liquid crystal composition containing at least one liquid crystal compound (liquid crystal molecule) and having positive or negative dielectric anisotropy can be used. Note that, hereinafter, a liquid crystal composition having positive dielectric anisotropy is also referred to as a positive liquid crystal, and a liquid crystal composition having negative dielectric anisotropy is also referred to as a negative liquid crystal. The liquid crystal composition may contain a liquid crystal compound having a fluorine atom, a hydroxy group, an amino group, a fluorine-containing group (e.g., a trifluoromethyl group), a cyano atom, an alkyl group, an alkoxy group, an alkenyl group, an isothiocyanate group, a heterocycle, a cycloalkane, a cycloalkene, a steroid skeleton, a benzene ring, or a naphthalene ring, or may contain a compound having two or more rigid moieties (mesogenic skeletons) that exhibit liquid crystal properties within the molecule (e.g., a bimesogenic compound in which two rigid biphenyl structures or terphenyl structures are linked by an alkyl group). The liquid crystal composition may be a liquid crystal composition exhibiting a nematic phase, a smectic phase, or a cholesteric phase. The liquid crystal composition may further contain additives to improve the liquid crystal alignment property, such as photopolymerizable monomers having a polymerizable group as described below, optically active compounds (e.g., S-811 manufactured by Merck Ltd.), antioxidants, ultraviolet absorbers, dyes, antifoaming agents, polymerization initiators, or polymerization inhibitors. Examples of the positive liquid crystal include ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, and MLC-7081 manufactured by Merck. Examples of negative liquid crystals include MLC-6608, MLC-6609, MLC-6610, and MLC-7026-100 manufactured by Merck. In addition, in the PSA mode, MLC-3023 manufactured by Merck is an example of a liquid crystal containing a compound having a polymerizable group.

[0090] (3-2) Manufacturing PSA type liquid crystal display elements The procedure is the same as in (3-1) above, except that a liquid crystal composition containing a compound having a polymerizable group is injected or dropped. Examples of the polymerizable compound include compounds having a polymerizable group such as those represented by the above formulas (M-1) to (M-7). (3-3) When a coating film is formed on a substrate using a liquid crystal alignment agent containing a compound having a polymerizable group A method for producing a liquid crystal display element may be employed in which a process similar to that described in (3-1) above is followed by a step of irradiating with ultraviolet light, which will be described later. This method, similar to the production of the PSA-type liquid crystal display element, allows for the production of a liquid crystal display element with excellent response speed with a small amount of light irradiation. The compound having a polymerizable group may be a compound having one or more polymerizable unsaturated groups, such as acrylate or methacrylate groups, in the molecule, as represented by the above formulae (M-1) to (M-7). The content of the compound is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of all polymer components. The polymerizable group may also be contained in a polymer used in a liquid crystal aligning agent. Examples of such polymers include polymers obtained by reacting a diamine component containing a diamine having the above photopolymerizable group at its terminal.

[0091] (4) Light irradiation step The liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates obtained in (3-2) or (3-3) above. The voltage applied here can be, for example, 5 to 50 V DC or AC. The light to be irradiated can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm, but ultraviolet light containing light with a wavelength of 300 to 400 nm is preferred. The light source for the irradiation light can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, or an excimer laser. The light irradiation dose is preferably 1,000 to 200,000 J / m 2 and more preferably 1,000 to 100,000 J / m 2 is.

[0092] A liquid crystal display element can be obtained by laminating a polarizing plate to the outer surface of the liquid crystal cell. Examples of polarizing plates that can be laminated to the outer surface of the liquid crystal cell include a polarizing film called an "H film" made by stretching and aligning polyvinyl alcohol and absorbing iodine, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

[0093] The liquid crystal display element of the present invention can be effectively applied to various devices, and can be used in various display devices such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, information displays, etc. In addition, the polymer composition contained in the liquid crystal aligning agent can be used as a liquid crystal alignment film for a retardation film, a liquid crystal alignment film for a scanning antenna or a liquid crystal array antenna, or a liquid crystal alignment film for a transmissive / scattering liquid crystal dimming element, or for other applications such as a protective film for a color filter, a gate insulating film for a flexible display, or a substrate material. [Example]

[0094] 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 of the compounds used and the methods for measuring the physical properties are as follows:

[0095] (organic solvent) NMP: N-methyl-2-pyrrolidone GBL: gamma-butyrolactone BCS: Butyl cellosolve (acid dianhydride) CA-1 to CA-4: Compounds represented by the following formulas (CA-1) to (CA-4), respectively (diamine) DA-1 to DA-3: Compounds represented by the following formulas (DA-1) to (DA-3), respectively [ka] [ka]

[0096] <Viscosity measurement> The viscosity of the solution was measured 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). <Molecular weight measurement> The molecular weight was measured using a room temperature GPC (gel permeation chromatography) device, and the number average molecular weight (Mn) and weight average molecular weight (Mw) were calculated as polyethylene glycol and polyethylene oxide equivalent values. GPC apparatus: GPC-101 (Showa Denko K.K.), columns: GPC KD-803 and GPC KD-805 (Showa Denko K.K.) in series, column temperature: 50°C, eluent: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr·HO) 30 mmol / L, phosphoric acid anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L), flow rate: 1.0 mL / min Standard samples for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000, and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: approximately 12,000, 4,000, and 1,000) (manufactured by Polymer Laboratory Co., Ltd.).

[0097] <Synthesis Example 1> DA-1 (2.20 g, 9.11 mmol), DA-2 (1.48 g, 3.90 mmol), CA-4 (0.976 g, 3.90 mmol), NMP (22.2 g), and GBL (3.20 g) were added to a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube and stirred at 40 °C for 3 h. CA-1 (1.68 g, 8.58 mmol) and NMP (9.54 g) were then added and stirred at 40 °C for 3 h to obtain a 15% solids polyamic acid solution (1) (viscosity: 808 mPa s). The Mn of this polyamic acid was 13,680 and the Mw was 36,660. <Synthesis Example 2> DA-1 (2.20 g, 9.11 mmol), DA-2 (1.48 g, 3.90 mmol), CA-1 (1.68 g, 8.58 mmol), NMP (27.5 g), and GBL (2.00 g) were added to a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube and stirred at 40 °C for 3 h. CA-3 (0.851 g, 3.90 mmol) and NMP (4.80 g) were then added and stirred at room temperature for 3 h to obtain a 15% solids polyamic acid solution (2) (viscosity: 1,262 mPa s). The Mn of this polyamic acid was 12,540 and the Mw was 32,650. <Synthesis Example 3> DA-1 (2.20 g, 9.11 mmol), DA-2 (1.48 g, 3.90 mmol), CA-1 (1.68 g, 8.58 mmol), NMP (24.5 g), and GBL (6.02 g) were added to a 50 mL four-neck flask equipped with a stirrer and nitrogen inlet, and the mixture was stirred at 40 °C for 3 h. CA-2 (1.15 g, 3.90 mmol) and NMP (6.51 g) were then added and the mixture was stirred at room temperature for 3 h to obtain a 15% solids polyamic acid solution (3) (viscosity: 2,010 mPa s). The Mn of this polyamic acid was 14,330 and the Mw was 35,880.

[0098] <Comparative Synthesis Example 1> DA-3 (2.78 g, 14.0 mmol), DA-2 (2.28 g, 6.00 mmol), CA-4 (1.50 g, 6.00 mmol), and NMP (26.2 g) were added to a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube and stirred at 60 °C for 3 h. CA-1 (2.72 g, 13.9 mmol) and NMP (10.9 g) were then added and stirred at 40 °C for 3 h to obtain a 20% solids polyamic acid solution (4) (viscosity: 591 mPa s). The Mn of this polyamic acid was 10,220 and the Mw was 28,290. <Comparative Synthesis Example 2> DA-3 (2.78 g, 14.0 mmol), DA-2 (2.28 g, 6.00 mmol), CA-1 (2.63 g, 13.4 mmol), and NMP (30.7 g) were added to a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube and stirred at 40 °C for 3 h. CA-3 (1.31 g, 6.00 mmol) and NMP (5.20 g) were then added and stirred at room temperature for 3 h to obtain a 20% solids polyamic acid solution (5) (viscosity: 656 mPa s). The Mn of this polyamic acid was 10,550 and the Mw was 27,590. <Comparative Synthesis Example 3> DA-3 (2.78 g, 14.0 mmol), DA-2 (2.28 g, 6.00 mmol), CA-1 (2.63 g, 13.4 mmol), and NMP (30.7 g) were added to a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube and stirred at 40 °C for 3 h. CA-2 (1.76 g, 6.00 mmol) and NMP (7.10 g) were then added and stirred at room temperature for 3 h to obtain a 20% solids polyamic acid solution (6) (viscosity: 880 mPa s). The Mn of this polyamic acid was 10,370 and the Mw was 26,040.

[0099] The specifications of the polymers obtained in the above synthesis examples are shown in Table 1 below. [Table 1]

[0100] <Preparation of Liquid Crystal Alignment Agent> Example 1 NMP (9.00 g) and BCS (10.8 g) were added to the polyamic acid solution (1) (7.20 g) obtained in Synthesis Example 1, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (A-1). (Examples 2 and 3) Liquid crystal alignment agents (A-2) and (A-3) of Examples 2 and 3 were obtained in the same manner as in Example 1, except that polyamic acid solutions (2) and (3) were used instead of polyamic acid solution (1), respectively. (Comparative Example 1) NMP (11.0 g) and BCS (11.0 g) were added to the polyamic acid solution (4) (5.50 g) obtained in Comparative Synthesis Example 1, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (B-1). (Comparative Examples 2 and 3) Liquid crystal alignment agents (B-2) and (B-3) of Comparative Examples 2 and 3 were obtained in the same manner as in Comparative Example 1, except that polyamic acid solutions (5) and (6) were used instead of polyamic acid solution (4).

[0101] The specifications of the liquid crystal aligning agents obtained in the above Examples and Comparative Examples are shown in Table 2 below. [Table 2]

[0102] The liquid crystal alignment agents (A-1) to (A-3) and (B-1) to (B-3) obtained as described above did not show any abnormalities such as turbidity or precipitation, and were confirmed to be homogeneous solutions. The refractive index and residual DC voltage were evaluated using the obtained liquid crystal alignment agents.

[0103] [Refractive index measurement] The liquid crystal alignment agents (A-1) to (A-3) and (B-1) to (B-3) obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were spin-coated onto a silicon substrate, baked on a hot plate at 70°C for 90 seconds, and then baked in an infrared heating furnace at 230°C for 20 minutes to prepare a silicon substrate with a liquid crystal alignment agent having a film thickness of 100 nm. Next, the refractive index was measured using an M-2000 manufactured by J.A. Woollam Japan, and the refractive index at 550 nm was compared. The results are shown in Table 3 below.

[0104] [Preparation of liquid crystal cells for evaluation of residual DC characteristics] Liquid crystal cells were fabricated using the liquid crystal alignment agents (A-1), (A-3), (B-1), and (B-3) obtained in Examples 1 and 3 and Comparative Examples 1 and 3, as described below. The liquid crystal alignment agent was spin-coated onto a glass substrate with an ITO electrode, dried on a hot plate at 70°C for 90 seconds, and then baked in an infrared oven at 230°C for 20 minutes to form a 100 nm-thick liquid crystal alignment film. Two substrates with this liquid crystal alignment film were prepared. One of the substrates had 4 μm diameter bead spacers (JGC Catalysts and Chemicals, Shinshikyu, SW-D1) applied to the liquid crystal alignment film, followed by printing with a thermosetting sealant (Kyoritsu Chemical Industry, XN-1500T). The other substrate was then bonded to the first substrate, with the side with the liquid crystal alignment film facing inward. The resulting substrate was then heated at 150°C for 60 minutes to cure the sealant, producing an empty cell. Liquid crystal MLC-3023 (negative liquid crystal, manufactured by Merck) was injected into this empty cell by the vacuum injection method to prepare a liquid crystal cell. Next, with a DC voltage of 15 V applied to this liquid crystal cell, UV light of 10 J / cm 2 was applied from the outside of the liquid crystal cell through a cut filter for wavelengths of 325 nm or less. 2 The UV irradiance was measured using a UV-MO3A manufactured by ORC. After that, in order to deactivate any unreacted polymerizable compound remaining in the liquid crystal cell, the cell was irradiated with UV (UV lamp: FLR40SUV32 / A-1) for 30 minutes using a UV-FL irradiation device manufactured by Toshiba Lighting & Technology Corporation, with no voltage applied.

[0105] [Evaluation of residual DC voltage] A 30 Hz, 7.8 Vpp square wave voltage superimposed on 2 V DC was applied to the liquid crystal cell prepared above for 100 hours at 25°C. One hour after the DC voltage was turned off, the residual voltage (residual DC voltage) remaining in the liquid crystal cell was measured using the flicker elimination method. This value serves as an indicator of image retention caused by DC accumulation, and a value of 60 mV or less indicates excellent image retention, i.e., "good," while a value greater than 60 mV is considered "poor." The results are shown in Table 3 below.

[0106] [Table 3]

[0107] As shown in Table 3, the liquid crystal alignment agent (A-1) of Example 1, which contains the polyamic acid solution (1) obtained using the diamine compound (DA-1) as a raw material, exhibited a higher refractive index of the resulting liquid crystal alignment film than the liquid crystal alignment agent (B-1) of Comparative Example 1, which contains the polyamic acid solution (4) obtained from the monomer component containing the diamine compound (DA-3) instead of the diamine compound (DA-1). Also, when the liquid crystal alignment agent (A-2) of Example 2 was compared with the corresponding liquid crystal alignment agent (B-2) of Comparative Example 2, and when the liquid crystal alignment agent (A-3) of Example 3 was compared with the corresponding liquid crystal alignment agent (B-3) of Comparative Example 3, the refractive index of the resulting liquid crystal alignment film was also higher when the liquid crystal alignment agents of the Examples were used. Furthermore, it can be seen that when the liquid crystal alignment agents obtained in Examples 1 and 3 are used, a liquid crystal alignment film can be obtained that exhibits good characteristics in the evaluation of residual DC voltage, compared to the liquid crystal alignment agents obtained in Comparative Examples 1 and 3.

[0108] In addition, the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2021-004415, filed on January 14, 2021, are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims

1. a first repeating unit (a1) selected from the group consisting of a repeating unit represented by the following formula (1) and an imidized structure of the repeating unit represented by the formula (1); A liquid crystal aligning agent containing a polymer component having a repeating unit represented by the following formula (2) and a second repeating unit (a2) selected from the group consisting of imidized structures of the repeating unit represented by the formula (2): 【Chemistry 1】 (X １ , X ２ represents a tetravalent organic group. １ represents a divalent organic group having a structure represented by the following formula (S): ２ represents a divalent organic group having a partial structure represented by the following formula (2c), and Y in the formula (2) ２ has a partial structure represented by the formula (2c) in the main chain direction. １ , R ２ each independently represents a hydrogen atom or a monovalent organic group. １ , Z ２ each independently represents a hydrogen atom or a monovalent organic group. 【Chemistry 2】 (X is a single bond, -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -O-, -COO-, -OCO- or -((CH ２ ) ａ１ -A １ ) ｍ１ - (a1 is an integer from 1 to 15, A １ represents an oxygen atom or —COO—, m １ is an integer of 1 to 2. １ When is 2, multiple a1 and A １ are each independently defined as above.) J represents a monovalent organic group having at least one group selected from the group consisting of alicyclic hydrocarbon groups having 4 to 40 carbon atoms and aromatic hydrocarbon groups having 6 to 40 carbon atoms, provided that at least one hydrogen atom possessed by the alicyclic hydrocarbon group and aromatic hydrocarbon group is substituted with a substituent selected from the group consisting of a halogen atom, a halogen-atom-containing alkyl group, a halogen-atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group in which a carbon-carbon bond possessed by any methylene group of the halogen-atom-containing alkyl group, halogen-atom-containing alkoxy group, alkyl group, alkoxy group, and alkenyl group is interrupted by an oxygen atom. * represents a bond.) 【Transformation 3】 (Any hydrogen atom on the benzene ring may be substituted with a monovalent substituent. * represents a bond.)

2. 2. The liquid crystal aligning agent according to claim 1, wherein the polymer component is at least one polymer selected from the group consisting of a polyimide precursor having the repeating unit (a1) and the repeating unit (a2) in the same molecule and a polyimide having an imidized structure thereof.

3. 3. The polymer according to claim 2, wherein the total of the first repeating unit (a1) and the second repeating unit (a2) is 5 to 100 mol % of all repeating units constituting the copolymer, 3. The liquid crystal aligning agent according to claim 2, wherein the content of the repeating unit (a1) is 1 to 90 mol % of all repeating units constituting the polymer.

4. The polymer component is a mixture of at least one polymer (P-a1) selected from the group consisting of polyimide precursors having the repeating unit (a1) and polyimides having the imidized structure thereof, and at least one polymer (P-a2) selected from the group consisting of polyimide precursors having the repeating unit (a2) and polyimides having the imidized structure thereof, the liquid crystal aligning agent according to claim 1.

5. The liquid crystal aligning agent according to any one of claims 1 to 4, wherein the structure represented by the formula (S) is a structure represented by any one of the following formulas (S1) to (S2): 【Chemistry 4】 (X １ is a single bond, -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -O-, -COO-, -OCO- or -((CH ２ ) ａ１ -A １ ) ｍ１ - (a1 is an integer from 1 to 15, A １ represents an oxygen atom or —COO—, m １ is an integer of 1 to 2. １ When is 2, multiple a1 and A １ and each independently have the same definition as above. G １ represents a divalent cyclic group selected from divalent aromatic hydrocarbon groups having 6 to 12 carbon atoms and divalent alicyclic hydrocarbon groups having 4 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine atom-containing alkyl group having 1 to 3 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. m is an integer of 1 to 4. When m is 2 or more, a plurality of X １ , G １ are each independently defined above. R １ represents a fluorine atom, a fluorine atom-containing alkyl group having 1 to 10 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 10 carbon atoms, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, or an alkoxyalkyl group having 3 to 10 carbon atoms. 【Transformation 5】 (X ２ is -CONH-, -NHCO-, -O-, -CH ２ represents —O—, —COO—, or —OCO—. ２ represents a structure having a steroid skeleton, wherein at least one hydrogen atom of the structure having a steroid skeleton is substituted with a substituent selected from the group consisting of a halogen atom, a halogen-atom-containing alkyl group, a halogen-atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group in which a carbon-carbon bond of any methylene group of the halogen-atom-containing alkyl group, halogen-atom-containing alkoxy group, alkyl group, alkoxy group, and alkenyl group is interrupted by an oxygen atom.

6. The formula (S1) is a structure represented by any one of the following formulas (S1-x1) to (S1-x7), and the formula (S2) is a structure represented by the following formula (S2-x): The liquid crystal aligning agent according to claim 5. 【Transformation 6】 (In formulas (S1-x1) to (S1-x7), X ｐ is -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CO-N(CH ３ )-, -NH-, -O-, -CH ２ O-, -CH ２ It is —OCO—, —COO—, or —OCO—. １ represents an oxygen atom or -COO-* (where the bond marked with "*" is (CH ２ ) ａ２ (combines with), A ２ represents an oxygen atom or *-COO- (where the bond marked with "*" is (CH ２ ) ａ２ ) and a ３ is 0 or 1, and a １ and a ２ are each independently an integer of 1 to 10, and Cy is a 1,4-cyclohexylene group or a 1,4-phenylene group. １ represents a fluorine atom, a fluorine atom-containing alkyl group having 1 to 10 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 10 carbon atoms, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, or an alkoxyalkyl group having 3 to 10 carbon atoms. 【Transformation 7】 (In formula (S2-x), X represents formula (X1), formula (X2), or formula (X3); Col represents formula (Col1), formula (Col2), or formula (Col3); G represents formula (G1), formula (G2), formula (G3), or formula (G4); Me represents a methyl group; and * represents a bond.)

7. In the formula (1), Y １ The liquid crystal aligning agent according to any one of claims 1 to 6, wherein is a divalent organic group derived from a diamine represented by the following formula (d1) or formula (d2): 【Transformation 8】 (X is a single bond, —O—, —C(CH ３ ) ２ -, -NH-, -CO-, -(CH ２ ) ｍ -, -SO ２ -, -O-(CH ２ ) ｍ -O-, -OC(CH ３ ) ２ -, -CO-(CH ２ ) ｍ -, -NH-(CH ２ ) ｍ -, -SO ２ - (CH ２ ) ｍ -, -CONH-(CH ２ ) ｍ -, -CONH-(CH ２ ) ｍ -NHCO- or -COO-(CH ２ ) ｍ represents a divalent organic group of —OCO—. m is an integer of 1 to 8. Y represents a structure represented by the above formula (S). In the above formula (d2), the two Ys may be the same or different.

8. Y in the formula (2) ２ The liquid crystal aligning agent according to any one of claims 1 to 6, wherein the main chain direction of the liquid crystal aligning agent is one or two partial structures represented by the formula (2c).

9. Y in the formula (2) ２ The liquid crystal aligning agent according to any one of claims 1 to 7, wherein is a divalent organic group represented by the formula (2c).

10. The polymer component is a tetracarboxylic acid component containing a tetracarboxylic acid dianhydride represented by the following formula (T) or a derivative thereof, and a polyimide obtained using the tetracarboxylic acid component, and the polyimide which is an imidized structure thereof. The liquid crystal aligning agent according to any one of claims 1 to 9, is composed of at least one polymer selected from the group consisting of a polyimide precursor obtained using the tetracarboxylic acid component containing a tetracarboxylic acid dianhydride represented by the following formula (T) or a derivative thereof. 【Chemistry 9】 (X represents a structure selected from any of the following formulas (x-1) to (x-13).) 【Chemistry 10】 (R １ ~R ４ R each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. ５ and R ６ each independently represents a hydrogen atom or a methyl group; j and k are integers of 0 or 1; A １ and A ２ each independently represents a single bond, —O—, —CO—, —COO—, phenylene, sulfonyl, or an amide group. *1 is a bond bonded to one acid anhydride group, and *2 is a bond bonded to the other acid anhydride group. In the above formula (x-13), ２ may be the same or different.)

11. The liquid crystal aligning agent according to any one of claims 1 to 10, further comprising at least one crosslinkable compound selected from the group consisting of a compound having two or more of at least one group selected from the group consisting of an epoxy group, an isocyanate group, an oxetane ring, an oxazoline ring, and a cyclocarbonate group, a hydroxy group, a compound having two or more of at least one group selected from the group consisting of a hydroxyalkyl group and a lower alkoxyalkyl group, and a compound having a blocked isocyanate group.

12. A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of claims 1 to 11.

13. A liquid crystal display device comprising the liquid crystal alignment film according to claim 12.

14. A method for manufacturing a liquid crystal display element, comprising the following steps (1) to (4): Step (1): A step of applying the liquid crystal aligning agent according to any one of claims 1 to 11 onto a substrate. Step (2): Step of baking the coating film Step (3): Step of forming a liquid crystal layer Step (4): Light irradiation step

15. 15. The method for producing a liquid crystal display element according to claim 14, wherein in the step (4), the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates.

16. 16. The method for producing a liquid crystal display element according to claim 14, wherein the light irradiated in the step (4) is ultraviolet light and visible light containing light having a wavelength of 150 to 800 nm.

17. In the step (4), the irradiation amount of the light to be irradiated is 1,000 to 200,000 J / m ２ The method for producing a liquid crystal display element according to any one of claims 14 to 16,

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