Liquid crystal alignment agent, liquid crystal alignment film and its manufacturing method, liquid crystal element, liquid crystal display device, and polymer

Abstract

To provide a liquid crystal device that has a small change in liquid crystal alignment even after long-time backlight irradiation and has high reliability.SOLUTION: A polymer (P) having a partial structure represented by the formula (1) is contained in a liquid crystal alignment agent. In the formula, Rβ is a monovalent hydrocarbon group having 1-10 carbon atoms, a cyano group, a nitro group, a chlorine atom, a bromine atom, an iodine atom, -SiR2R3R4, -P(=O)R2R3, -C≡CR2, or -NR2R3, or is a monovalent group Rω1 obtained by substituting an arbitrary methylene group in a monovalent hydrocarbon group having 2-10 carbon atoms with -O-, -S-, or -NR2-, or is a monovalent group obtained by substituting an arbitrary hydrogen atom included in a group Rω1 or a monovalent hydrocarbon group having 1-10 carbon atoms with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group. Rα is a hydrogen atom, a monovalent hydrocarbon group having 1-10 carbon atoms or the like.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film and a method for producing the same, a liquid crystal element, a liquid crystal display device, and a polymer. [Background technology]

[0002] In liquid crystal devices, liquid crystal alignment films are used to control the alignment of liquid crystal molecules in the liquid crystal layer. Liquid crystal alignment films are generally formed using a liquid crystal aligning agent containing a polymer component. Conventional methods for obtaining organic films with liquid crystal alignment control power include rubbing an organic film, oblique vapor deposition of silicon oxide, and forming a monomolecular film with a long-chain alkyl group, as well as a method of irradiating a photosensitive organic film with light (photoalignment method).

[0003] The photo-alignment method can uniformly impart liquid crystal alignment to a film while suppressing the generation of static electricity and dust, and thus has been extensively studied in recent years (see, for example, Patent Documents 1 and 2). Patent Documents 1 and 2 disclose the formation of a liquid crystal alignment film by the photo-alignment method using a polymer having a cinnamate structure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2007 / 071091 [Patent Document 2] International Publication No. 2016 / 080033 Summary of the Invention [Problem to be solved by the invention]

[0005] Liquid crystal alignment films (photo-alignment films) obtained by photo-alignment treatment tend to have less ability to align liquid crystal molecules than those obtained by rubbing treatment. Therefore, when liquid crystal devices are operated for a long time, changes in retardation can occur due to prolonged backlight exposure, and the initial alignment direction of the liquid crystals can gradually shift from the initial orientation direction. Such changes in alignment can manifest as image retention (afterimages), reduced transmittance, and reduced black brightness. Liquid crystal devices are expected to offer even higher display quality to meet the demand for ever-higher performance in recent years.

[0006] The present invention has been made in view of the above problems, and has as its main object to provide a highly reliable liquid crystal element in which the liquid crystal alignment changes little even after long-term backlight irradiation. [Means for solving the problem]

[0007] According to the present invention, the following means are provided.

[0008] <1> A liquid crystal aligning agent comprising a polymer (P) having a partial structure represented by the following formula (1): [ka] (In formula (1), R β represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, a cyano group, a nitro group, a chlorine atom, a bromine atom, an iodine atom, -SiR 2 R 3 R 4 , -P(=O)R 2 R 3 , -C≡CR 2 or -NR 2 R 3 or any methylene group in the monovalent hydrocarbon group having 2 to 10 carbon atoms is -O-, -S- or -NR 2 a monovalent group R ω1 or a group R ω1Alternatively, R is a monovalent group in which any hydrogen atom in a monovalent hydrocarbon group having 1 to 10 carbon atoms has been substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group. α represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, a cyano group, a nitro group, a halogen atom, or -SiR 2 R 3 R 4 , -P(=O)R 2 R 3 , -COOR 2 , -C≡CR 2 or -NR 2 R 3 or any methylene group in the monovalent hydrocarbon group having 2 to 10 carbon atoms is -O-, -S- or -NR 2 a monovalent group R ω2 or a group R ω2 Alternatively, R is a monovalent group in which any hydrogen atom in a monovalent hydrocarbon group having 1 to 10 carbon atoms has been substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group. 2 , R 3 , and R 4 are each independently a hydrogen atom or a monovalent organic group. 1 is an oxygen atom or -NR 5 -R 5 is a hydrogen atom or a monovalent organic group. 1 is a substituent. n is an integer of 0 to 4. m is 0 or 1. "*" represents a bond.

[0009] <2> the above <1> A method for producing a liquid crystal alignment film, comprising: a step of applying the liquid crystal aligning agent of the above formula (1) onto a substrate to form a coating film; and a step of irradiating the coating film with light. <3> the above <1> A liquid crystal alignment film formed using the liquid crystal alignment agent of the above. <4> the above <3> A liquid crystal element comprising a liquid crystal alignment film.

[0010] <5> The present invention relates to a liquid crystal display device having a plurality of pixels, the liquid crystal display device comprising: a first substrate, a second substrate facing the first substrate, a liquid crystal layer provided between the first substrate and the second substrate and containing liquid crystal molecules, a first alignment film formed on the first substrate for aligning the liquid crystal molecules, and a second alignment film formed on the second substrate for aligning the liquid crystal molecules. In the liquid crystal display device, at least one of the first alignment film and the second alignment film is a photo-alignment film, and each pixel among the plurality of pixels has a first alignment region, a second alignment region, a third alignment region, and a fourth alignment region as regions in which the alignment orientations of the liquid crystal molecules are different from one another, the first alignment region, the second alignment region, the third alignment region, and the fourth alignment region are arranged side by side in the longitudinal direction of the pixel, and the alignment orientation of the first alignment region, the alignment orientation of the second alignment region, the alignment orientation of the third alignment region, and the alignment orientation of the fourth alignment region are different from one another. the difference between any two of the orientation directions is approximately equal to an integral multiple of 90 degrees, the plurality of pixels are arranged side by side in the short-side direction of the pixels so that the orientation directions of the orientation regions adjacent to each other in the short-side direction of the pixels are the same, and in each of the first orientation region, the second orientation region, the third orientation region, and the fourth orientation region, one of the pretilt angle determined by the first orientation film and the pretilt angle determined by the second orientation film is less than 90 degrees, and the other is substantially 90 degrees, and the photo-alignment film is <1> The liquid crystal alignment agent is formed using the above.

[0011] <6> A polymer having a partial structure represented by the above formula (1). [Effects of the Invention]

[0012] According to the above-mentioned configuration, a highly reliable liquid crystal element can be obtained in which the liquid crystal alignment changes little even after long-term backlight irradiation. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of a liquid crystal display device. [Figure 2]FIG. 1 is a diagram showing an example of an alignment pattern in one pixel of a liquid crystal display device. [Figure 3] 1 shows an example of an alignment pattern in each pixel of a liquid crystal display device, where (a) shows the first substrate and (b) shows the second substrate. DETAILED DESCRIPTION OF THE INVENTION

[0014] Matters related to the embodiments of the present disclosure will be described in detail below. In this specification, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The term "chain hydrocarbon group" refers to a straight-chain hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure and is composed only of a chain structure. However, it may be saturated or unsaturated. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. However, it does not have to be composed only of an alicyclic hydrocarbon structure and may include groups that have a chain structure as part of it. The term "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, it does not have to be composed only of an aromatic ring structure and may contain a chain structure or an alicyclic hydrocarbon structure as part of it.

[0015] The term "aliphatic hydrocarbon group" encompasses linear hydrocarbon groups and alicyclic hydrocarbon groups. The term "main chain" of a polymer refers to the longest "trunk" portion of the atomic chain of the polymer. The term "side chain" of a polymer refers to the portion branched from the "trunk" of the polymer. The term "organic group" refers to an atomic group formed by removing any hydrogen atom from a compound containing carbon (i.e., an organic compound). The term "(meth)acrylate" encompasses acrylate and methacrylate. The term "(meth)acrylic" encompasses acrylic and methacrylic.

[0016] Liquid crystal alignment agent The liquid crystal aligning agent of the present disclosure contains a polymer (P) having a partial structure represented by the following formula (1). [ka] (In formula (1), Rβ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, a cyano group, a nitro group, a chlorine atom, a bromine atom, an iodine atom, -SiR 2 R 3 R 4 , -P(=O)R 2 R 3 , -C≡CR 2 or -NR 2 R 3 or any methylene group in the monovalent hydrocarbon group having 2 to 10 carbon atoms is -O-, -S- or -NR 2 a monovalent group R ω1 or a group R ω1 Alternatively, R is a monovalent group in which any hydrogen atom in a monovalent hydrocarbon group having 1 to 10 carbon atoms has been substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group. α represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, a cyano group, a nitro group, a halogen atom, or -SiR 2 R 3 R 4 , -P(=O)R 2 R 3 , -COOR 2 , -C≡CR 2 or -NR 2 R 3 or any methylene group in the monovalent hydrocarbon group having 2 to 10 carbon atoms is -O-, -S- or -NR 2 a monovalent group R ω2 or a group R ω2 Alternatively, R is a monovalent group in which any hydrogen atom in a monovalent hydrocarbon group having 1 to 10 carbon atoms has been substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group. 2 , R 3 , and R 4 are each independently a hydrogen atom or a monovalent organic group. 1 is an oxygen atom or -NR 5 -R 5 is a hydrogen atom or a monovalent organic group. 1 is a substituent. n is an integer of 0 to 4. m is 0 or 1. "*" represents a bond.

[0017] <Polymer (P)> The partial structure represented by the above formula (1) that the polymer (P) has has a substituent (R β In the above formula (1), R β Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by the formula include an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 6 to 10 carbon atoms.

[0018] The alkyl group having 1 to 10 carbon atoms may be linear or branched, and specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Examples of cycloalkyl groups having 3 to 10 carbon atoms include a cyclopentyl group, a cyclohexyl group, and a methylcyclohexyl group. Examples of aryl groups having 6 to 10 carbon atoms include a phenyl group and a tolyl group. Examples of aralkyl groups having 6 to 10 carbon atoms include a benzyl group.

[0019] R β is a monovalent hydrocarbon group having 2 to 10 carbon atoms, in which any methylene group is -O-, -S-, or -NR 2 -substituted monovalent group (R ω1 ) is a group in which one or more methylene groups in the alkyl group having 2 to 10 carbon atoms, the cycloalkyl group having 3 to 10 carbon atoms, the aryl group having 6 to 10 carbon atoms, or the aralkyl group having 6 to 10 carbon atoms are -O-, -S-, or -NR 2 -substituted groups. ω1 Further specific examples include an alkoxy group, an alkoxyalkyl group, a group having a (poly)alkylene glycol chain, a cycloalkoxy group, an arylalkoxy group, and an aralkyloxy group.

[0020] R βWhen the group represented by the formula (I) is a monovalent group in which any hydrogen atom in a monovalent hydrocarbon group having 1 to 10 carbon atoms has been substituted with a halogen atom, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. β Specific examples of the group represented by the formula (I) above that is a monovalent group substituted with a halogen atom include a trifluoromethyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a trichloromethyl group, and a bromomethyl group.

[0021] R β is a group R ω1 Alternatively, specific examples of a monovalent group in which any hydrogen atom of a monovalent hydrocarbon group having 1 to 10 carbon atoms has been substituted with a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group include a cyanomethyl group, an aminomethyl group, a 2-aminoethyl group, an N-(aminomethyl)methyl group, a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a hydroxymethyloxymethyl group, a thiolmethyl group, a 2-thiolethyl group, and a nitromethyl group.

[0022] R 2 , R 3 , and R 4 Examples of the monovalent organic group represented by the formula (I) include a monovalent hydrocarbon group having 1 to 10 carbon atoms and an alkoxy group having 1 to 10 carbon atoms. Specific examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms include R β Examples of the alkoxy group having 1 to 10 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group.

[0023] R is a highly reliable liquid crystal display that is resistant to deterioration even after prolonged exposure to backlight. β Among these, -SiR is a monovalent hydrocarbon group having 1 to 10 carbon atoms, a cyano group, a nitro group, a chlorine atom, a bromine atom, an iodine atom, 2 R 3 R 4 , -P(=O)R 2 R 3, -C≡CR 2 or -NR 2 R 3 or any methylene group in the monovalent hydrocarbon group having 2 to 10 carbon atoms is -O-, -S- or -NR 2 a monovalent group R ω1 or a group R ω1 or a monovalent group in which any hydrogen atom of a monovalent hydrocarbon group having 1 to 10 carbon atoms has been substituted with a halogen atom, a cyano group, or a nitro group, and is preferably an alkyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, a trialkylsilyl group, a cyano group, a bromine atom, an iodine atom, -NR 12 R 13 (However, R 12 and R 13 each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent hydrocarbon group having 2 to 10 carbon atoms with -O-, -S-, or -NR between its carbon-carbon bond; 2 - (where R 2 is preferably a hydrogen atom or a monovalent organic group. β Among these, particularly, represents an alkyl group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a trialkylsilyl group, or —NR 12 R 13 More preferably, it is a methyl group, an ethyl group or a trialkylsilyl group.

[0024] The partial structure represented by the above formula (1) has a hydrogen atom or a substituent at the α-position of the carbonyl carbon. α is a monovalent hydrocarbon group having 1 to 10 carbon atoms, -SiR 2 R 3 R 4 , -P(=O)R 2 R 3 , -C≡CR 2 or -NR 2 R 3 When the group R ω2 and the group R ω2Specific examples of the monovalent group obtained by substituting any hydrogen atom of a monovalent hydrocarbon group having 1 to 10 carbon atoms with a halogen atom, a cyano group, or a nitro group include R β Examples of the group represented by R include the same groups as those exemplified above. α When "-COOR" is a halogen atom, specific examples include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 2 Specific examples of "" include an alkyloxycarbonyl group, a cycloalkyloxycarbonyl group, an aryloxycarbonyl group, and the like.

[0025] R α is a group represented by the formula (I) in which any methylene group in a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, or a monovalent hydrocarbon group having 2 to 10 carbon atoms is -O-, -S-, or -NR 2 - (wherein R 2 is preferably a hydrogen atom or a monovalent organic group, more preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a cyano group, even more preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyano group, and still more preferably a hydrogen atom.

[0026] X 1 The group represented by -NR 5 -If R 5 Examples of the monovalent organic group represented by R include a monovalent hydrocarbon group having 1 to 10 carbon atoms and a monovalent thermally detachable group. 5 Specific examples of when R is a monovalent hydrocarbon group include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 4 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 6 to 10 carbon atoms. Among these, an alkyl group having 1 to 6 carbon atoms, a cyclohexyl group, and a phenyl group are preferred, and an alkyl group having 1 to 3 carbon atoms is more preferred. 5 is bonded to another group and 5may be a ring structure formed together with the nitrogen atom to which the group is bonded. Examples of such ring structures include a piperidine structure and a piperazine structure.

[0027] R 5 When is a monovalent thermally detachable group, the thermally detachable group is preferably a monovalent group that is detached by heating during film formation. Specific examples of the thermally detachable group include a tert-butoxycarbonyl group (Boc group), a benzyloxycarbonyl group, a 1,1-dimethyl-2-haloethyloxycarbonyl group, an allyloxycarbonyl group, and a 2-(trimethylsilyl)ethoxycarbonyl group. Among these, the Boc group is particularly preferred because it has excellent thermal detachment properties and can reduce the amount of the detached structure remaining in the film.

[0028] X 1 is, among others, an oxygen atom, -NH-, -N(CH3)- or -NR 15 -(R 15 is preferably a Boc group), and more preferably an oxygen atom.

[0029] R 1 Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a halogen atom, a hydroxyl group, a carboxyl group, an amino group, a cyano group, an alkylsilyl group, an alkoxysilyl group, an ester group, etc. n is preferably 0 to 2, more preferably 0 or 1, and even more preferably 0. When m is 1, the bond (*) in formula (1) represents a bond to another group (organic group). When m is 1, the bond (*) in formula (1) may be bonded to an atom constituting the main chain of the polymer or to an atom constituting the side chain. When m is 0, the partial structure represented by the above formula (1) may be present at the terminal portion of the main chain of the polymer or at the terminal portion of the side chain.

[0030] The main skeleton of the polymer (P) is not particularly limited. From the viewpoint of obtaining good heat resistance, mechanical strength, affinity with liquid crystal, etc., the polymer (P) is preferably at least one selected from the group consisting of polyamic acid, polyimide, polyamic acid ester, polyorganosiloxane, and addition polymer. The polymer (P) may have the partial structure represented by the above formula (1) in the main chain, in the side chain, or in both the main chain and the side chain. Preferred examples of the polymer (P) will be described below.

[0031] [Polyamic acid] The polyamic acid (hereinafter also referred to as "polyamic acid (P)") as the polymer (P) can be obtained by polymerizing a monomer having the partial structure represented by the above formula (1). Examples of methods for producing the polyamic acid (P) include: [1] a method for polymerizing a monomer containing a tetracarboxylic dianhydride (hereinafter also referred to as "specific acid-free dihydrate") having the partial structure represented by the above formula (1); [2] a method for polymerizing a monomer containing a diamine (hereinafter also referred to as "specific diamine") having the partial structure represented by the above formula (1); and [3] a method for polymerizing a monomer containing the specific acid-free dihydrate and the specific diamine. Among these, the use of the specific diamine is preferred because the synthesis of the monomer is relatively easy, and the method [2] above is more preferred.

[0032] (Tetracarboxylic acid dianhydride) ·Specified acid dianhydride The specific acid dianhydride is not particularly limited in structure of other parts as long as it has the partial structure represented by the above formula (1). The specific acid dianhydride preferably has the partial structure represented by the above formula (1) in its main chain. Specific examples of the specific acid dianhydride include compounds represented by the following formulas (5-1) to (5-4). [ka]

[0033] Other acid dianhydrides In the above methods [1] and [3], the tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid (P) may be the specific acid dianhydride alone, or a tetracarboxylic acid dianhydride not having the partial structure represented by the above formula (1) (hereinafter also referred to as "other acid dianhydrides") may be used in combination. In the above method [2], other acid dianhydrides are used as the tetracarboxylic acid dianhydride when synthesizing the polyamic acid (P). Examples of other acid dianhydrides include aliphatic tetracarboxylic acid dianhydrides and aromatic tetracarboxylic acid dianhydrides. Examples of aliphatic tetracarboxylic acid dianhydrides include linear tetracarboxylic acid dianhydrides and alicyclic tetracarboxylic acid dianhydrides.

[0034] Specific examples of these include chain tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride; Alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, and the like; Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol bisanhydrotrimate, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, and 4,4'-carbonyldiphthalic anhydride. In addition, the tetracarboxylic dianhydrides described in JP-A-2010-97188 can be used. The tetracarboxylic dianhydrides can be used alone or in combination of two or more.

[0035] The tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid preferably contains at least one selected from the group consisting of chain tetracarboxylic acid dianhydrides and alicyclic tetracarboxylic acid dianhydrides, and more preferably contains an alicyclic tetracarboxylic acid dianhydride, in terms of increasing the solubility of the polymer and enabling the production of a liquid crystal alignment film exhibiting good electrical properties. The amount of the alicyclic tetracarboxylic acid dianhydride used is preferably 20 mol % or more, more preferably 40 mol % or more, and even more preferably 50 mol % or more, based on the total amount of tetracarboxylic acid dianhydrides used in the synthesis of the polyamic acid.

[0036] (diamine) Specific diamines The specific diamine used in the synthesis of the polyamic acid (P) is not particularly limited as long as it has the partial structure represented by the above formula (1). The specific diamine may have the partial structure represented by the above formula (1) in its main chain or in its side chain. Examples of the specific diamine include compounds represented by the following formula (6-1) and compounds represented by the following formula (6-2). [ka] (In formula (6-1), A 1 is a divalent group represented by the above formula (1). 1 and Y 2 are each independently a single bond or a divalent organic group. [ka] (In formula (6-2), A 2 is a divalent group represented by the above formula (1). 3 is a trivalent aromatic ring group. 4 is a single bond or a divalent linking group. 5 is a hydrogen atom or a monovalent organic group.

[0037] In the above formula (6-1), Y 1 and Y2 Examples of the divalent organic group represented by the formula (I) include a divalent hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon group in which some of the methylene groups are -O-, -CO-, -COO-, or -NR 30 -(R 30 is a divalent group in which Y is substituted with a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, or a divalent heterocyclic group, which may have a substituent. Examples of the divalent heterocyclic group include groups in which two hydrogen atoms have been removed from a nitrogen-containing heterocycle such as pyridine, piperazine, or piperidine. Y 1 and Y 2 Examples of the substituent that may be possessed by the group include a halogen atom, an alkoxy group, a hydroxyl group, a carboxyl group, a cyano group, and a nitro group.

[0038] In the above formula (6-2), Y 3 The trivalent aromatic ring group represented by the formula (I) is a group in which three hydrogen atoms have been removed from the ring portion of an aromatic ring. Examples of the aromatic ring include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, and an anthracene ring; and aromatic heterocycles such as a pyridine ring and a pyridazine ring. Of these, a benzene ring and a pyridine ring are particularly preferred. A substituent may be introduced into the aromatic ring of the aromatic ring group. Examples of the substituent include an alkyl group having 1 to 3 carbon atoms, a halogen atom, and a hydroxyl group.

[0039] Y 4 Examples of the divalent linking group represented by the formula: 30 -, -CO-NR 30 -, and an alkanediyl group having 1 to 3 carbon atoms.

[0040] Y 5 Examples of the monovalent organic group represented by the formula (I) include a monovalent hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon group in which some of the methylene groups are -O-, -CO-, -COO-, or -NR 30 Examples of the group include a monovalent group substituted with -, a monovalent heterocyclic group, and the like, which may have a substituent.

[0041] Specific examples of the specific diamine include, as the compound represented by the above formula (6-1), for example, compounds represented by each of the following formulas (6-1-1) to (6-1-22); and as the compound represented by the above formula (6-2), for example, compounds represented by each of the following formulas (6-2-1) to (6-2-4). [ka] [ka] [ka] [ka]

[0042] [ka]

[0043] Other diamines In the above-mentioned methods [2] and [3], the diamine used in the synthesis of the polyamic acid (P) may be the specific diamine alone, or a diamine not having the partial structure represented by the above-mentioned formula (1) (hereinafter also referred to as "other diamine") may be used in combination. In the above-mentioned method [1], other diamines are used as the diamine when synthesizing the polyamic acid (P). Examples of other diamines include aliphatic diamines, aromatic diamines, and diaminoorganosiloxanes. Examples of aliphatic diamines include linear diamines and alicyclic diamines.

[0044] Specific examples of diamines used in the synthesis of polyamic acid include chain diamines such as metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, and hexamethylenediamine; Alicyclic diamines such as 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine); Aromatic diamines include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4-aminophenyl-4-aminobenzoate, 4,4'-diaminoazobenzene, 1,5-bis(4-aminophenoxy)pentane, 1,2-bis(4-aminophenoxy)ethane, 1,6-bis(4-aminophenoxy)hexane, bis[2-(4-aminophenyl)ethyl]hexanedioic acid, 2,6-diaminopyridine, 1,4-bis-(4-aminophenyl)-piperazine, 2,2'-dimethyl-4,4'-diaminobiphenyl, and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl. Main chain diamines such as 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(phenylenediisopropylidene)bisaniline, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]dianiline, 4,4'-diaminobenzanilide, 4,4'-diaminostilbenzene, and 1,4-bis(4-aminophenyl)-piperazine: Dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy-2,4-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, 3,5-di Cholestanyl aminobenzoate, cholestenyl 3,5-diaminobenzoate, lanostaniyl 3,5-diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 5ξ-cholestan-3-yl 3,5-diaminobenzoate, the following formula (E-1): [ka] (In formula (E-1), X I and X II are each independently a single bond, -O-, *-COO- or *-OCO- (where "*" represents X I It shows the bond with R. I is an alkanediyl group having 1 to 3 carbon atoms. II R is a single bond or an alkanediyl group having 1 to 3 carbon atoms. III is an alkyl group, alkoxy group, fluoroalkyl group, or fluoroalkoxy group having 1 to 20 carbon atoms. a is 0 or 1. b is an integer of 0 to 3. c is an integer of 0 to 2. d is 0 or 1, provided that 1≦a+b+c≦3. Side chain diamines such as compounds represented by the formula: Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and the diamines described in JP-A-2010-97188 can also be used.

[0045] Examples of other diamines include diamines having a -NR- (where R is a monovalent hydrocarbon group or a thermally eliminable group having 1 to 10 carbon atoms) or a nitrogen-containing heterocyclic structure (hereinafter also referred to as "nitrogen-containing diamines"). Examples of nitrogen-containing diamines include, in addition to the corresponding compounds among the other diamines exemplified above, N4,N4'-bis-(4-aminophenyl)-N4,N4'-dimethylbiphenyl-4,4'-diamine, N,N'-di(5-amino-2-pyridyl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine, 6,6'-(pentamethylenedioxy)bis(3-aminopyridine), 3,5-diamino-N,N-bis(pyridin-3-ylmethyl)benzamide, and 4-(4-aminophenoxycarbonyl)-1-(4-aminophenyl)piperidine. In synthesizing the polyamic acid (P), one diamine may be used alone or two or more diamines may be used in combination.

[0046] In the polyamic acid (P), the content of the partial structure represented by the above formula (1) is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, based on the total diamine units contained in the polyamic acid (P). Furthermore, the content of the partial structure represented by the above formula (1) in the polyamic acid (P) is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less, based on the total diamine units contained in the polyamic acid (P). When the content of the partial structure represented by the above formula (1) in the polyamic acid (P) is within the above range, the polyamic acid (P) has good photoreactivity and is advantageous in that it can form an alignment film that exhibits good liquid crystal alignment properties even after prolonged backlight irradiation.

[0047] Synthesis of polyamic acid The polyamic acid (P) can be obtained by reacting the above-mentioned tetracarboxylic dianhydride with a diamine, optionally together with a molecular weight modifier. The ratio of the tetracarboxylic dianhydride and the diamine used in the synthesis reaction of the polyamic acid (P) is preferably such that 0.2 to 2 equivalents of the acid anhydride group of the tetracarboxylic dianhydride are used per equivalent of the amino group of the diamine.

[0048] Examples of molecular weight modifiers include acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The proportion of the molecular weight modifier used is preferably 20 parts by mass or less per 100 parts by mass of the total of the tetracarboxylic dianhydride and diamine used.

[0049] The synthesis reaction of the polyamic acid (P) is preferably carried out in an organic solvent. The reaction temperature is preferably −20° C. to 150° C., and the reaction time is preferably 0.1 to 24 hours. Examples of organic solvents used in the reaction include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Particularly preferred organic solvents include one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenols, or a mixture of one or more of these solvents with other organic solvents (e.g., butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount (a) of the organic solvent used is preferably an amount such that the total amount (b) of the tetracarboxylic dianhydride and the diamine is 0.1 to 50% by mass relative to the total amount (a+b) of the reaction solution.

[0050] In this manner, a reaction solution containing the polyamic acid (P) dissolved therein is obtained. This reaction solution may be used as is for preparing a liquid crystal aligning agent, or the polyamic acid (P) contained in the reaction solution may be isolated and then used for preparing a liquid crystal aligning agent.

[0051] (Polyamic acid ester) The polyamic acid ester (hereinafter also referred to as "polyamic acid ester (P)") as the polymer (P) can be obtained, for example, by [I] a method of reacting the polyamic acid (P) obtained by the above synthesis reaction with an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester with a diamine including a specific diamine, or [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine including a specific diamine. The polyamic acid ester (P) contained in the liquid crystal aligning agent of the present disclosure may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist. The reaction solution in which the polyamic acid ester (P) is dissolved may be used directly for preparing the liquid crystal aligning agent, or the polyamic acid ester (P) contained in the reaction solution may be isolated and then used for preparing the liquid crystal aligning agent.

[0052] (Polyimide) The polyimide (hereinafter also referred to as "polyimide (P)") as the polymer (P) can be obtained, for example, by dehydrating and cyclizing the polyamic acid (P) synthesized as described above to form an imidized product. The polyimide (P) may be a fully imidized product in which all of the amic acid structures contained in its precursor polyamic acid (P) have been dehydrated and cyclized, or a partially imidized product in which only a portion of the amic acid structures have been dehydrated and cyclized, resulting in both amic acid structures and imide ring structures. The polyimide (P) preferably has an imidization rate of 20% or more, more preferably 30 to 95%. The imidization rate is the ratio, expressed as a percentage, of the number of imide ring structures to the total number of amic acid structures and imide ring structures in the polyimide. Here, some of the imide rings may be isoimide rings.

[0053] The dehydration ring closure of the polyamic acid (P) is preferably carried out by dissolving the polyamic acid (P) in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating as necessary. In this method, the dehydrating agent may be, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride. The amount of the dehydrating agent used is preferably 0.01 to 20 mol per mol of the amic acid structure of the polyamic acid (P). The dehydration ring closure catalyst may be, for example, a tertiary amine such as pyridine, collidine, lutidine, or triethylamine. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 mol per mol of the dehydrating agent used. Examples of organic solvents used in the dehydration ring closure reaction include the organic solvents exemplified for use in the synthesis of the polyamic acid (P). The reaction temperature for the dehydration ring closure reaction is preferably 0 to 180°C. The reaction time is preferably 1.0 to 120 hours. The reaction solution containing the polyimide (P) obtained by the above reaction may be used for preparing a liquid crystal aligning agent as it is, or the polyimide (P) may be isolated and then used for preparing a liquid crystal aligning agent. The polyimide (P) can also be obtained by imidizing a polyamic acid ester (P).

[0054] The solution viscosity of the polyamic acid, polyamic acid ester, and polyimide contained in the liquid crystal alignment agent is preferably 10 to 800 mPa·s, and more preferably 15 to 500 mPa·s, when the solution is made into a 10% by mass solution. The solution viscosity (mPa·s) is a value measured at 25°C using an E-type rotational viscometer for a 10% by mass polymer solution prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0055] The polystyrene-equivalent weight average molecular weight (Mw) of the polyamic acid, polyamic acid ester, and polyimide measured by gel permeation chromatography (GPC) is preferably 1,000 to 500,000, and more preferably 5,000 to 100,000. The molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC, is preferably 15 or less, and more preferably 10 or less.

[0056] (Polyorganosiloxane) The method for producing the polyorganosiloxane (hereinafter also referred to as "polysiloxane (P)") as the polymer (P) is not particularly limited as long as it has the partial structure represented by the above formula (1). The polysiloxane (P) can be obtained, for example, by the hydrolysis and condensation reaction of a hydrolyzable silane compound. Specific examples include the following methods [1] and [2].

[0057] [1] A method of synthesizing an epoxy group-containing polyorganosiloxane by hydrolysis and condensation of a hydrolyzable silane compound (ms-1) having an epoxy group, or a mixture of the silane compound (ms-1) and other silane compounds, and then reacting the obtained epoxy group-containing polyorganosiloxane with a carboxylic acid having a partial structure represented by the above formula (1) (hereinafter also referred to as "specific carboxylic acid"). [2] A method of hydrolyzing and condensing a hydrolyzable silane compound (ms-2) having a partial structure represented by the above formula (1), or a mixture of the silane compound (ms-2) and another silane compound. Among these, method [1] is preferable because it is simple and easy and can increase the introduction rate of the partial structure represented by the above formula (1) in the polysiloxane (P).

[0058] Specific examples of the silane compound (ms-1) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethylmethyldimethoxysilane, 2-glycidoxyethyldimethylmethoxysilane, 2-glycidoxyethyldimethylethoxysilane, 4-glycidoxybutyltrimethoxysilane, 4-glycidoxybutylmethyldimethoxysilane, 4-glycidoxybutylmethyldiethoxysilane, 4-glycidoxybutyldimethylmethoxysilane, 4-glycidoxybutyldimethylethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, and 3-(3,4-epoxycyclohexyl)propyltrimethoxysilane. As the silane compound (ms-1), one of these compounds can be used alone, or two or more of them can be used in combination.

[0059] The other silane compounds used in the synthesis of the epoxy group-containing polyorganosiloxane are not particularly limited as long as they are hydrolyzable silane compounds, and specific examples thereof include alkoxysilanes such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxysilane; Nitrogen- and sulfur-containing alkoxysilanes, such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(3-cyclohexylamino)propyltrimethoxysilane, and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane; Examples of the silane compounds include unsaturated hydrocarbon-containing alkoxysilanes such as 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 6-(meth)acryloyloxyhexyltrimethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and p-styryltrimethoxysilane; and trimethoxysilylpropylsuccinic anhydride. These other silane compounds may be used alone or in combination of two or more. In this specification, the term "(meth)acryloxy" encompasses both "acryloxy" and "methacryloxy."

[0060] The hydrolysis and condensation reaction of silane compounds can be carried out by reacting one or more of the above-mentioned silane compounds with water, preferably in the presence of a suitable catalyst and organic solvent. The proportion of water used in the reaction is preferably 1 to 30 moles per mole of the total amount of silane compounds. Examples of catalysts include acids, alkali metal compounds, organic bases, titanium compounds, and zirconium compounds. The amount of catalyst used varies depending on the type of catalyst, reaction conditions such as temperature, and should be appropriately determined. For example, the amount is preferably 0.01 to 3 moles per mole of the total amount of silane compounds. Examples of organic solvents used include hydrocarbons, ketones, esters, ethers, and alcohols. Among these, water-insoluble or slightly water-soluble organic solvents are preferred. The proportion of the organic solvent used is preferably 10 to 10,000 parts by mass per 100 parts by mass of the total amount of silane compounds used in the reaction.

[0061] The hydrolysis-condensation reaction is preferably carried out by heating, for example, in an oil bath. The heating temperature is preferably 130°C or lower, and the heating time is preferably 0.5 to 12 hours. After the reaction is complete, the organic solvent layer separated from the reaction solution is dried with a desiccant, if necessary, and the solvent is then removed to obtain the desired polysiloxane. The method for synthesizing polysiloxane is not limited to the hydrolysis-condensation reaction described above; for example, a method in which a hydrolyzable silane compound is reacted in the presence of oxalic acid and an alcohol may also be used.

[0062] In the method [1] above, the epoxy group-containing polyorganosiloxane obtained by the above reaction is then reacted with a specific carboxylic acid, whereby the epoxy group of the epoxy group-containing polyorganosiloxane reacts with the carboxyl group of the specific carboxylic acid to obtain a polyorganosiloxane (P) having the partial structure represented by the above formula (1) in its side chain.

[0063] Specific examples of the specific carboxylic acid include compounds represented by the following formulas (7-1) to (7-5). [ka]

[0064] The content of the partial structure represented by the above formula (1) in one molecule of polysiloxane (P) is preferably 5 mol % or more, more preferably 10 mol % or more, and even more preferably 15 mol % or more, based on the silicon atoms in polysiloxane (P). Furthermore, the content of the partial structure represented by the above formula (1) in one molecule of polysiloxane (P) is preferably 70 mol % or less, more preferably 60 mol % or less, and even more preferably 50 mol % or less, based on the silicon atoms in polysiloxane (P). A content of the partial structure represented by the above formula (1) in polysiloxane (P) within the above range is preferable in that it can improve the photoreactivity of polysiloxane (P) and can form an alignment film that exhibits good liquid crystal alignment properties even after long-term backlight irradiation.

[0065] In addition, when synthesizing the polysiloxane (P), the carboxylic acid used in the reaction with the epoxy group-containing polyorganosiloxane may be the specific carboxylic acid alone, or other carboxylic acids other than the specific carboxylic acid may be used in combination. The other carboxylic acid may be any carboxylic acid that does not have the partial structure represented by the above formula (1), and various carboxylic acids can be used. Examples of other carboxylic acids include carboxylic acids having a mesogenic structure.

[0066] The reaction of the epoxy group-containing polyorganosiloxane with the carboxylic acid can be preferably carried out in the presence of a catalyst and an organic solvent. Examples of the catalyst include organic bases and compounds known as curing accelerators (e.g., tertiary organic amines, quaternary organic amines, quaternary ammonium salts, etc.) that accelerate the reaction of epoxy compounds. The amount of catalyst used is preferably 100 parts by mass or less, more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the epoxy group-containing polyorganosiloxane.

[0067] Examples of organic solvents used in the above reaction include hydrocarbons, ethers, esters, ketones, amides, and alcohols. The organic solvent is preferably used in a proportion such that the solids concentration (the proportion of the total mass of components other than the solvent in the reaction solution to the total weight of the solution) is 0.1% by mass or more, and more preferably 5 to 50% by mass. In the above reaction, the reaction temperature is preferably 0 to 200°C, more preferably 50 to 150°C. The reaction time is preferably 0.1 to 50 hours, more preferably 0.5 to 20 hours. After completion of the reaction, it is preferable to wash the organic solvent layer separated from the reaction solution with water. After washing with water, the organic solvent layer is dried with an appropriate desiccant, if necessary, and the solvent is then removed to obtain the target polysiloxane (P).

[0068] The polysiloxane (P), when prepared into a 10% by mass solution, preferably has a solution viscosity of 1 to 500 mPa·s, and more preferably 3 to 200 mPa·s.The polysiloxane (P) has a weight average molecular weight (Mw) measured by GPC in terms of polystyrene of preferably 1,000 to 200,000, more preferably 2,000 to 50,000, and even more preferably 3,000 to 20,000.

[0069] (addition polymer) The method for producing the addition polymer (hereinafter also referred to as "addition polymer (P)") as polymer (P) is not particularly limited as long as it has the partial structure represented by the above formula (1). The addition polymer (P) is a polymer having a structural unit derived from a monomer having a polymerizable carbon-carbon unsaturated bond. The addition polymer (P) can be obtained, for example, by polymerizing an unsaturated monomer (ma-1) having the partial structure represented by the above formula (1), or a mixture of the unsaturated monomer (ma-1) and another unsaturated monomer.

[0070] As the unsaturated monomer, any monomer having a polymerizable carbon-carbon unsaturated bond can be used. Examples of such monomers include compounds having a (meth)acryloyl group, a vinyl group, a vinylphenyl group, a maleimide group, etc. As the unsaturated polymer (P), at least one selected from the group consisting of poly(meth)acrylate, a maleimide polymer, and a styrene-maleimide copolymer can be preferably used, since it can form a liquid crystal alignment film having excellent liquid crystal alignment properties.

[0071] The unsaturated monomer (ma-1) is not particularly limited as long as it has the partial structure represented by the above formula (1). Specific examples of the unsaturated monomer (ma-1) include compounds represented by the following formulas (8-1) to (8-10). [ka] (In formulas (8-1) to (8-4), R represents a hydrogen atom or a methyl group.) [ka]

[0072] Specific examples of other unsaturated monomers include (meth)acrylic compounds such as unsaturated carboxylic acids, such as (meth)acrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, and vinylbenzoic acid; unsaturated carboxylic acid esters, such as alkyl (meth)acrylates (e.g., methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.), cycloalkyl (meth)acrylates, benzyl (meth)acrylate, trimethoxysilylpropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, and 4-hydroxybutyl glycidyl ether (meth)acrylate; and unsaturated polycarboxylic acid anhydrides, such as maleic anhydride; Aromatic vinyl compounds such as styrene, methylstyrene, divinylbenzene, and 4-(glycidyloxymethyl)styrene; conjugated diene compounds such as 1,3-butadiene and 2-methyl-1,3-butadiene; Examples of the unsaturated monomer include maleimide compounds such as N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, 4-(2,5-dioxo-3-pyrrolin-1-yl)benzoic acid, N-(4-glycidyloxyphenyl)maleimide, N-glycidylmaleimide, 3-maleimidobenzoic acid, 3-maleimidopropionic acid, 3-(2,5-dioxo-3-pyrrolin-1-yl)benzoic acid, and methyl 4-(2,5-dioxo-3-pyrrolin-1-yl)benzoate. When synthesizing the addition polymer (P), one type of other unsaturated monomer may be used alone, or two or more types may be used in combination.

[0073] The content of the partial structure represented by formula (1) in one molecule of addition polymer (P) is preferably 1 mol % or more, more preferably 2 mol % or more, and even more preferably 5 mol % or more, based on the total structural units of addition polymer (P). Furthermore, the content of the partial structure represented by formula (1) in one molecule of addition polymer (P) is preferably 60 mol % or less, more preferably 50 mol % or less, and even more preferably 40 mol % or less, based on the total structural units of addition polymer (P). A content of the partial structure represented by formula (1) in the addition polymer (P) within the above range is preferred in that it improves the photoreactivity of addition polymer (P) and enables the formation of an alignment film that exhibits good liquid crystal alignment properties even after prolonged backlight irradiation.

[0074] The addition polymer (P) can be obtained, for example, by polymerizing the monomers in the presence of a polymerization initiator. The polymerization initiator used is preferably an azo compound such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), or 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile). The polymerization initiator is preferably used in an amount of 0.01 to 30 parts by mass relative to 100 parts by mass of all the monomers used in the reaction.

[0075] The polymerization reaction is preferably carried out in an organic solvent. Examples of organic solvents used in the reaction include alcohols, ethers, ketones, amides, esters, and hydrocarbon compounds, with diethylene glycol ethyl methyl ether and propylene glycol monomethyl ether acetate being preferred. The reaction temperature is preferably 30°C to 120°C, and the reaction time is preferably 1 to 36 hours. The amount of organic solvent (a) used is preferably such that the total amount of monomers (b) used in the reaction is 0.1 to 60% by mass relative to the total amount of the reaction solution (a+b).

[0076] The weight average molecular weight (Mw) of the addition polymer (P) measured by GPC in terms of polystyrene is preferably 250 to 500,000, and more preferably 500 to 100,000.

[0077] The method for producing the addition polymer (P) is not limited to the above, and it can also be obtained, for example, by a method in which a monomer containing an unsaturated monomer (m-1) having an epoxy group is polymerized in the presence of a polymerization initiator, and then the obtained polymer is reacted with a specific carboxylic acid.

[0078] When the polymer (P) has the partial structure represented by the above formula (1) in its main chain, the polymer (P) is preferably at least one selected from the group consisting of polyamic acid, polyimide, and polyamic acid ester, from the viewpoint of ease of introduction of the partial structure represented by the above formula (1). When the polymer (P) has the partial structure represented by the above formula (1) in its side chain, the polymer (P) is preferably at least one selected from the group consisting of polyamic acid, polyimide, polyamic acid ester, polyorganosiloxane, and addition polymer.

[0079] <Other ingredients> The liquid crystal aligning agent of the present disclosure may further contain a component (hereinafter also referred to as "other component") different from the polymer (P). The other component may include a polymer (hereinafter also referred to as "polymer (Q)") that does not have the partial structure represented by the above formula (1), a crosslinking agent, a solvent, etc.

[0080] (Polymer (Q)) The polymer (Q) can be used for the purpose of improving the solubility of the polymer component, the alignment property and electrical properties of the liquid crystal alignment film, etc. Examples of the polymer (Q) include polymers having a main skeleton such as polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyamide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, and addition polymer. When preparing the liquid crystal alignment agent, one type of polymer (Q) may be used alone, or two or more types may be used in combination.

[0081] The polymer (Q) is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, and addition polymer, in terms of improving the liquid crystal alignment property and electrical properties of the resulting liquid crystal element. Specific examples of polyamic acid, polyamic acid ester, and polyimide as the polymer (Q) include polymers obtained by reacting the other acid dianhydrides described above with other diamines. The addition polymer as the polymer (Q) is preferably a polymer obtained using one or more monomers having a (meth)acryloyl group, a vinyl group, a vinylphenyl group, or a maleimide group, and is preferably at least one selected from the group consisting of poly(meth)acrylate, a maleimide polymer, and a styrene-maleimide copolymer.

[0082] When the polymer (Q) is contained in the liquid crystal aligning agent, the content ratio of the polymer (Q) in the liquid crystal aligning agent is preferably 20 to 99.9 parts by mass, more preferably 30 to 99 parts by mass, relative to 100 parts by mass of the total amount of the polymer (P) and the polymer (Q).

[0083] When the liquid crystal aligning agent contains the polymer (Q), the content of the polymer (P) in the liquid crystal aligning agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of the polymer (Q). The content of the polymer (P) is preferably 150 parts by mass or less, more preferably 120 parts by mass or less, and even more preferably 100 parts by mass or less, relative to 100 parts by mass of the polymer (Q).

[0084] (Crosslinking agent) The liquid crystal aligning agent of the present disclosure may contain a crosslinking agent. By blending a crosslinking agent in the liquid crystal aligning agent, it is possible to enhance the effect of improving reliability against long-term irradiation of a backlight, which is preferable.

[0085] The crosslinking agent is preferably a compound having a functional group capable of reacting with a functional group (e.g., an amino group, a carboxyl group, an epoxy group, a polymeric unsaturated bond group, etc.) possessed by the polymer (P). Specifically, it is preferably a compound having a molecular weight of 1,000 or less and having at least one selected from the group consisting of a cyclic ether group, a carboxyl group, a cyclic carbonate group, an alcoholic hydroxyl group, an amino group, a protected amino group, a protected isocyanate group, a trialkoxysilyl group, and a polymerizable unsaturated bond group. The number of crosslinkable groups possessed by the crosslinking agent is preferably 2 or more, more preferably 3 or more, and even more preferably 3 to 8.

[0086] When a crosslinking agent is blended, the content of the crosslinking agent in the liquid crystal aligning agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of the total amount of polymer components in the liquid crystal aligning agent. Furthermore, from the viewpoint of suppressing performance degradation due to the addition of an excessive amount, the content of the crosslinking agent is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, relative to 100 parts by mass of the total amount of polymer components in the liquid crystal aligning agent. The crosslinking agent may be used alone or in combination of two or more.

[0087] (solvent) The liquid crystal aligning agent of the present disclosure is preferably prepared as a liquid composition in which the polymer (P) and other components used as needed are dispersed or dissolved in a suitable solvent. The solvent used is preferably an organic solvent, such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, or ethylene glycol-i-propyl. ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate, etc. These can be used alone or in combination of two or more.

[0088] Examples of other components include, in addition to the solvent, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, etc. The blending ratios of these can be appropriately selected depending on each compound within a range that does not impair the effects of the present disclosure.

[0089] The solids 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 1 to 10 mass%. That is, the liquid crystal aligning agent is applied to the surface of a substrate as described below, and preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that will become a liquid crystal alignment film. In this case, a solids concentration of 1 mass% or more is preferable because it ensures a sufficient thickness of the coating film and makes it easy to obtain a good liquid crystal alignment film. Furthermore, a solids concentration of 10 mass% or less allows the coating film to have an unduly thick thickness, thereby making it possible to obtain a good liquid crystal alignment film, and also ensures an appropriate viscosity of the liquid crystal aligning agent, resulting in good applicability.

[0090] From the viewpoint of fully obtaining the effects of the present disclosure, the content ratio of the polymer component in the liquid crystal alignment agent is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 50% by mass or more, relative to 100 parts by mass of the total of solid components (i.e., components other than the solvent) in the liquid crystal alignment agent.

[0091] <Liquid crystal alignment film and liquid crystal element> The liquid crystal alignment film of the present disclosure is formed using the liquid crystal alignment agent prepared as described above. Furthermore, the liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The operation mode of the liquid crystal in the liquid crystal element is not particularly limited, and various modes such as TN (Twisted Nematic), STN (Super Twisted Nematic), VA (Vertical Alignment) (including VA-MVA, VA-PVA, etc.), IPS (In-Plane Switching), FFS (Fringe Field Switching), and OCB (Optically Compensated Bend) can be applied. The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, different substrates are used depending on the desired operation mode. Steps 2 and 3 are common to all operation modes.

[0092] (Step 1: Formation of coating film) First, a liquid crystal alignment agent is applied to a substrate, and the coated surface is preferably heated to form a coating film on the substrate. Examples of substrates that can be used include transparent substrates made of glass, such as float glass or soda glass; or plastics, such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefin). Examples of transparent conductive films that can be provided on one side of the substrate include NESA films (registered trademarks of PPG, Inc., USA) made of tin oxide (SnO2) and ITO films made of indium oxide-tin oxide (In2O3-SnO2). When manufacturing TN, STN, or VA liquid crystal devices, two substrates with patterned transparent conductive films are used. On the other hand, when manufacturing IPS or FFS liquid crystal devices, one substrate is provided with electrodes made of a comb-shaped patterned transparent conductive film or metal film, and another substrate with no electrodes is used. Examples of metal films that can be used include films made of metals such as chromium. The liquid crystal alignment agent is applied to the substrate on the electrode-forming surface, preferably by offset printing, spin coating, roll coating, or inkjet printing.

[0093] After the liquid crystal aligning agent is applied, preliminary heating (pre-baking) is preferably carried out for the purpose of preventing dripping of the applied liquid crystal aligning agent, etc. The pre-baking temperature is preferably 30 to 150° C., more preferably 40 to 120° C. The pre-baking time is preferably 0.25 to 10 minutes.

[0094] Thereafter, the solvent is further removed, and a baking (post-baking) step is carried out, if necessary, to thermally imidize the amic acid structure present in the polymer. The baking temperature (post-baking temperature) at this time is preferably 250°C or lower, more preferably 230°C or lower, and even more preferably 180°C or lower, from the viewpoints of suppressing deterioration such as discoloration due to high temperatures when forming a liquid crystal alignment film on a color filter and reducing environmental impact. Furthermore, from the viewpoint of suppressing deterioration of liquid crystal alignment properties and reliability due to the influence of solvent components remaining in the film, the post-baking temperature is preferably 80°C or higher, more preferably 120°C or higher. The post-baking time is preferably 5 to 150 minutes. The film thickness of the film thus formed is preferably 0.001 to 1 μm. After applying the liquid crystal alignment agent to a substrate, the organic solvent is removed to form a liquid crystal alignment film or a coating film that will become a liquid crystal alignment film.

[0095] (Step 2: Alignment treatment) When manufacturing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal device, the coating film formed in step 1 above is subjected to a treatment (alignment treatment) to impart liquid crystal alignment ability. This imparts the ability to align liquid crystal molecules to the coating film, turning it into a liquid crystal alignment film. As the alignment treatment, a rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton or the like, or a photo-alignment treatment in which the coating film is irradiated with light to impart liquid crystal alignment ability, is preferably used. When manufacturing a vertical alignment type liquid crystal device, the coating film formed in step 1 above may be used as a liquid crystal alignment film as is, or the coating film may be subjected to an alignment treatment to further enhance the liquid crystal alignment ability.

[0096] The light irradiation in the photo-alignment treatment can be performed by irradiating the coating film after the post-bake step, irradiating the coating film after the pre-bake step but before the post-bake step, or irradiating the coating film while it is being heated in at least one of the pre-bake and post-bake steps. In the photo-alignment treatment, the radiation to be irradiated to the coating film can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm. Preferably, ultraviolet light containing light with a wavelength of 200 to 400 nm is used. When the radiation is polarized, it may be linearly polarized or partially polarized. Furthermore, when the radiation used is linearly polarized or partially polarized, irradiation may be performed 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.

[0097] Examples of light sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, and excimer lasers. The radiation dose is preferably 400 to 20,000 J / m 2 and more preferably 1,000 to 5,000 J / m 2 The light irradiation of the coating film may be carried out while heating the coating film in order to enhance reactivity. The method may further include a step of contacting the organic film that has been subjected to the light irradiation treatment with water, a water-soluble organic solvent, or a mixed solvent of water and a water-soluble organic solvent.

[0098] (Step 3: Construction of liquid crystal cell) Two substrates with liquid crystal alignment films formed thereon are prepared as described above, and a liquid crystal cell is fabricated by disposing a liquid crystal between the two opposing substrates. Examples of methods for fabricating a liquid crystal cell include: (1) placing the two substrates facing each other with a spacer between them so that the liquid crystal alignment films face each other, bonding the peripheries of the two substrates together using a sealant, injecting liquid crystal into the substrate surfaces and the cell gap defined by the sealant, and then sealing the injection hole; and (2) applying a sealant to predetermined locations on one substrate with a liquid crystal alignment film, dropping liquid crystal onto several predetermined locations on the liquid crystal alignment film, and then bonding the other substrate so that the liquid crystal alignment films face each other, while spreading the liquid crystal over the entire surface of the substrate (ODF method). The fabricated liquid crystal cell is preferably further heated to a temperature at which the liquid crystal used assumes an isotropic phase and then slowly cooled to room temperature to remove flow alignment that occurs during liquid crystal filling.

[0099] The sealing agent may be, for example, an epoxy resin containing a hardener and aluminum oxide spheres as spacers, such as photospacers and bead spacers.

[0100] Examples of the liquid crystal to be used include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred. Examples of nematic liquid crystals that can be used include Schiff base liquid crystals, azoxy liquid crystals, biphenyl liquid crystals, phenylcyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals, biphenylcyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, and cubane liquid crystals. These liquid crystals may also be used by adding, for example, cholesteric liquid crystals, chiral agents, and ferroelectric liquid crystals.

[0101] Next, if necessary, a polarizing plate is attached to the outer surface of the liquid crystal cell. Examples of polarizing plates include a polarizing film called an "H film" made by stretching and aligning polyvinyl alcohol and absorbing iodine, sandwiched between cellulose acetate protective films, or a polarizing plate made of the H film itself. This produces a liquid crystal device.

[0102] The liquid crystal element of the present disclosure can be effectively applied to various applications. Specifically, it can be used in various display devices such as watches, portable game machines, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays, as well as light control films. Furthermore, a liquid crystal element formed using the liquid crystal aligning agent of the present disclosure can also be applied to optical films such as retardation films.

[0103] 《Liquid crystal display device》 One embodiment of the liquid crystal display device of the present invention has a photo-alignment film formed using the liquid crystal aligning agent described above as a liquid crystal alignment film. The liquid crystal display device of the present invention will be described below with reference to the accompanying drawings as appropriate.

[0104] 1, a liquid crystal display device 10 includes a pair of substrates consisting of a first substrate 11 and a second substrate 12, and a liquid crystal layer 13 disposed between the first substrate 11 and the second substrate 12. The liquid crystal display device 10 is a thin film transistor (TFT) type liquid crystal display device. Note that the present invention may also be applied to other driving methods (e.g., a passive matrix method, a plasma address method, etc.).

[0105] The first substrate 11 is a TFT substrate in which pixel electrodes 15 made of a transparent conductor such as ITO (Indium Tin Oxide), TFTs serving as switching elements, and various wirings such as scanning lines and signal lines are arranged on the surface of a transparent substrate 14 made of glass, resin, etc., facing the liquid crystal layer 13. The second substrate 12 is a CF substrate in which a black matrix 17, a color filter 18, and a counter electrode 19 (also called a common electrode) made of a transparent conductor are arranged on the surface of a transparent substrate 16 made of glass, resin, etc., facing the liquid crystal layer 13.

[0106] The pair of substrates 11 and 12 are provided with liquid crystal alignment films that align liquid crystal molecules in a predetermined direction relative to the film surface. The liquid crystal alignment films are vertical alignment films. The liquid crystal display device 10 has, as the liquid crystal alignment films, a first alignment film 22 formed on the electrode arrangement surface of the first substrate 11 and a second alignment film 23 formed on the electrode arrangement surface of the second substrate 12.

[0107] The first substrate 11 and the second substrate 12 are arranged with a predetermined gap (cell gap) interposed between them, via spacers 24, so that the electrode arrangement surface of the first substrate 11 and the electrode arrangement surface of the second substrate 12 face each other. While FIG. 1 shows columnar spacers as the spacers 24, other spacers such as bead spacers may also be used. The pair of opposing substrates 11 and 12 are bonded together at their peripheries via a sealant 25. A liquid crystal composition is filled in the space surrounded by the first substrate 11, the second substrate 12, and the sealant 25. This forms a liquid crystal layer 13 between the first substrate 11 and the second substrate 12. The liquid crystal layer 13 is filled with liquid crystal having negative dielectric anisotropy.

[0108] Polarizing plates (not shown) are disposed on the outer sides of each of the first substrate 11 and the second substrate 12. A terminal area is provided on the outer edge of the first substrate 11. A driver IC or the like for driving the liquid crystal is connected to this terminal area, thereby driving the liquid crystal display device 10.

[0109] At least one of the first alignment film 22 and the second alignment film 23 is a photo-alignment film, and in this embodiment, at least the first alignment film 22 is a photo-alignment film. In this specification, the term "photo-alignment film" refers to a liquid crystal alignment film in which liquid crystal alignment ability is imparted by irradiating a coating film formed using a polymer having a photo-alignment group with polarized or unpolarized light. The term "photo-alignment group" refers to a functional group that imparts anisotropy to a film by a photoisomerization reaction, photodimerization reaction, photodecomposition reaction, photorearrangement reaction, or the like due to light irradiation.

[0110] The first alignment film 22 is subjected to a divided exposure by a photoalignment treatment so that the alignment direction of the liquid crystal molecules varies in each region. The first alignment film 22 is formed by irradiating a coating film formed using a liquid crystal alignment agent containing a polymer (P) having a partial structure represented by the above formula (1) with polarized radiation obliquely multiple times using a photomask (e.g., a polarizer). On the other hand, the second alignment film 23 is not dividedly exposed. In this embodiment, the second alignment film 23 is a coating film formed using the same liquid crystal alignment agent as the first alignment film 22, and is used as is without being irradiated with light. This makes the pretilt angle determined by the first alignment film 22 different from the pretilt angle determined by the second alignment film 23. Specifically, the pretilt angle determined by the first alignment film 22 is less than 90 degrees, and the pretilt angle determined by the second alignment film 23 is substantially 90 degrees.

[0111] In addition, instead of forming the second alignment film 23 without irradiating the organic film formed with the liquid crystal alignment agent with light to make the pretilt angle defined by the second alignment film 23 substantially 90 degrees, the entire surface of the organic film formed with the liquid crystal alignment agent may be exposed to unpolarized light from the substrate normal direction without using a photomask, thereby making the pretilt angle defined by the second alignment film 23 substantially 90 degrees. In this case, the exposure light for the second substrate 12 may be parallel or diffused light. The "pretilt angle" is the angle between the surface of the alignment film and the long axis direction of the liquid crystal molecules near the alignment film when the voltage is off.

[0112] The liquid crystal display device 10 has a plurality of pixels 30, which are arranged in a matrix in the display area of ​​the liquid crystal display device 10. Each pixel area of ​​the pixels 30 is divided into alignment areas, and has a plurality of areas in which the alignment directions of the liquid crystal molecules are different from each other. This compensates for the viewing angle characteristics of the liquid crystal display device 10.

[0113] In this specification, the term "pixel" refers to the smallest unit that expresses the shade (gradation) of each color in a display, and corresponds to the unit that expresses each gradation of R, G, B, etc. in a color filter display device, for example. Therefore, when referring to a "pixel," it refers to each of the R, G, and B pixels, rather than a color display pixel (picture element) that combines R, G, and B pixels. In other words, in the case of a color liquid crystal display device, one pixel corresponds to one of the colors of the color filter.

[0114] Fig. 2 shows an example of the alignment pattern of pixel 30. In Fig. 2(a), the cone represents a liquid crystal molecule 35, with the apex side of the cone facing the first substrate 11 and the bottom side of the cone facing the second substrate 12. Fig. 2(a) is a view of the liquid crystal display device 10 as seen from the second substrate 12 side.

[0115] As an example, as shown in FIG. 2(a), each pixel 30 has four alignment regions in which the alignment orientations of the liquid crystal molecules 35 are different from one another. These four alignment regions (first domain 31, second domain 32, third domain 33, and fourth domain 34) are arranged side by side in the longitudinal direction of the pixel 30 (Y direction in FIG. 2) within one pixel. The difference between any two alignment orientations of the liquid crystal molecules 35 in the first to fourth domains 31 to 34 is approximately equal to an integral multiple of 90 degrees. In this specification, unless otherwise specified, the "alignment orientation of liquid crystal molecules" refers to the alignment orientation of liquid crystal molecules near the center in the in-plane and thickness direction of the liquid crystal layer 13 when a voltage is applied to the liquid crystal display device 10.

[0116] Specifically, when the widthwise direction of the pixel 30 (the X direction in FIG. 2) is set to 0 degrees, the orientation direction of the liquid crystal molecules 35 is substantially 45 degrees in the first domain 31, substantially 135 degrees in the second domain 32, substantially 225 degrees in the third domain 33, and substantially 315 degrees in the fourth domain 34. As shown in FIG. 2(a), these four domains 31 to 34 are arranged in one pixel along the longitudinal direction of the pixel 30 in the order of the fourth domain 34, the second domain 32, the third domain 33, and the first domain 31. A signal line 36 is arranged at a position that divides the light-transmitting region of each pixel 30 (hereinafter also referred to as "pixel region") into two in the longitudinal direction of the pixel 30. The two domains (the fourth domain 34 and the second domain 32) that form one side of the pixel area divided by the signal line 36, and the two domains (the third domain 33 and the first domain 31) that form the other side, have liquid crystal molecules 35 aligned in directions that differ by 180 degrees from each other (see Figure 2(a)).

[0117] In this specification, the terms "substantially 45 degrees," "substantially 135 degrees," "substantially 225 degrees," and "substantially 315 degrees" refer to the ranges of 45 degrees ±0.5 degrees, 135 degrees ±0.5 degrees, 225 degrees ±0.5 degrees, and 315 degrees ±0.5 degrees, respectively. Each angle is preferably β degrees ±0.2 degrees, and more preferably β degrees ±0.1 degrees (where β is 45, 135, 225, or 315).

[0118] 2(b) and 2(c) are schematic diagrams showing the orientation (tilt orientation) of the long axis direction of the liquid crystal molecules on the alignment film surfaces of the substrates of one pixel 30 projected onto the substrates in the voltage-off state. In FIG. 2, (b) shows the first substrate 11, and (c) shows the second substrate 12. Arrow 37 in FIG. 2 indicates the tilt orientation. In the liquid crystal display device 10, the first alignment film 22 of the first alignment film 22 and the second alignment film 23 is irradiated with polarized radiation in a direction corresponding to the alignment orientation of the liquid crystal molecules 35, thereby imparting desired pretilt angle characteristics to each of the domains 31 to 34. On the other hand, the second alignment film 23 is not irradiated with polarized ultraviolet light. Through this exposure process, in the alignment regions of each of the first to fourth domains 31 to 34, the pretilt angle θ1 determined by the first alignment film 22 is less than 90 degrees, and the pretilt angle θ2 determined by the second alignment film 23 is substantially 90 degrees.

[0119] The pretilt angle θ1 should be smaller than the pretilt angle θ2 defined by the second alignment film 23. From the viewpoint of suppressing the response delay of the liquid crystal molecules 35, the pretilt angle θ1 is preferably 89.0 degrees or less, and more preferably 88.5 degrees or less. Furthermore, from the viewpoint of suppressing a decrease in the contrast of the liquid crystal display device 10, the pretilt angle θ1 is preferably 81.0 degrees or more, and more preferably 83.0 degrees or more. In this specification, the term "substantially 90 degrees" refers to a range of 90 degrees ±0.5 degrees.

[0120] 2(b), the tilt orientations on the first substrate 11 side are different in the first to fourth domains 31 to 34, and the difference in tilt orientation between any two domains is approximately equal to an integral multiple of 90 degrees. Specifically, when the short-side direction (X direction) of the pixel 30 is set to 0 degrees, the tilt orientations in each domain are substantially 45 degrees in the first domain 31, substantially 135 degrees in the second domain 32, substantially 225 degrees in the third domain 33, and substantially 315 degrees in the fourth domain 34.

[0121] 3, the pixels 30 of the liquid crystal display device 10 are arranged side by side in the short-side direction (X direction) of the pixels 30 so that the alignment directions of adjacent domains in the short-side direction (X direction) of the pixels 30 are the same. In FIG. 3, arrow 41 indicates the exposure direction of polarized radiation on a coating film formed using a liquid crystal alignment agent. Reference numeral 44 indicates a region corresponding to the fourth domain 34 of each pixel.

[0122] By forming the photo-alignment film in the liquid crystal display device 10 having the above configuration using a polymer (P) having a partial structure represented by the above formula (1), it is possible to obtain a highly reliable liquid crystal display device having high transmittance and being resistant to deterioration of liquid crystal alignment even after long-term backlight irradiation.

[0123] The liquid crystal display device 10 can be effectively used in a variety of applications, such as a clock, a portable game machine, a word processor, a notebook computer, a car navigation system, a camcorder, a PDA, a digital camera, a mobile phone, a smartphone, various monitors, a liquid crystal television, and an information display. [Example]

[0124] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0125] In the following examples and comparative examples, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer, the imidization ratio of the polyimide, and the epoxy equivalent were measured by the following methods.

[0126] [Weight average molecular weight (Mw) and number average molecular weight (Mn) of polymer] Mw and Mn are values ​​calculated as polystyrene measured by gel permeation chromatography under the following conditions. Column: TSKgel GRCXLII, manufactured by Tosoh Corporation Solvent: Tetrahydrofuran (for polyorganosiloxanes and addition polymers) or N,N-dimethylformamide solution containing lithium bromide and phosphoric acid (for polyamic acid esters) Temperature: 40℃ Pressure: 68kgf / cm 2

[0127] [Imidization rate] A solution containing polyimide was poured into pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. After that, it was dissolved in deuterated dimethyl sulfoxide and measured at room temperature using tetramethylsilane as a reference substance. 1 H-NMR was measured. 1 The imidization rate was calculated from the H-NMR spectrum using the following formula (E-1). Imidization rate (%) = (1-A 1 / A 2 ×α)×100 …(E-1) (In formula (E-1), A 1 is the peak area due to the proton of the NH group that appears at a chemical shift of around 10 ppm, and A 2 is the peak area due to other protons, and α is the ratio of the number of other protons to one proton of the NH group in the polymer precursor (polyamic acid).

[0128] [Epoxy equivalent] The epoxy equivalent was measured by the hydrochloric acid-methyl ethyl ketone method described in JIS C 2105.

[0129] The structural formulas of the compounds used in the present examples are shown below: Note that, for convenience, hereinafter, "compound represented by formula (X)" will be abbreviated simply as "compound (X)".

[0130] (Tetracarboxylic acid derivatives) [ka]

[0131] (diamine) [ka]

[0132] (Modifying carboxylic acid) [ka]

[0133] (unsaturated monomer) [ka] [ka]

[0134] (additives) [ka] [ka]

[0135] 1. Compound synthesis [Synthesis Example 1-1] Compound (DA-1) was synthesized according to the following scheme. [ka]

[0136] Synthesis of compound (DA-1-1) 16.5 g (100 mmol) of 4-nitrobenzaldehyde and 11.3 g (100 mmol) of cyanomalonic acid were dissolved in 500 ml of pyridine, and 25 ml of piperidine was added. The mixture was then reacted at 80°C for 5 hours. After the reaction, the mixture was cooled to room temperature, and 300 ml of ethyl acetate was added, followed by 200 ml of hydrochloric acid. After two separate separations with 300 ml of water, the solvent was removed using a rotary evaporator to obtain a solid. The resulting solid was stirred under reflux with 100 ml of water and 5 g of sodium hydroxide for 3 hours. After stirring, the pH was adjusted to 4 with hydrochloric acid, and the precipitated solid was collected by filtration, washed with water, and dried to obtain 20.3 g of compound (DA-1-1) as an intermediate.

[0137] Synthesis of compound (DA-1-2) 2.61 g (10.0 mmol) of compound (DA-1-1) and 1.38 g (10.0 mmol) of 4-nitroaniline were dissolved in 50 ml of dichloromethane and cooled to 0 ° C. Next, 1.86 g (12.0 mmol) of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and 0.61 g (4.99 mmol) of 4-dimethylaminopyridine were added, and the mixture was allowed to react overnight after returning to room temperature. After that, the mixture was separated once with 50 ml of 1 N hydrochloric acid and three times with 50 ml of water. The organic layer was evaporated using a rotary evaporator to obtain 3.27 g of compound (DA-1-2).

[0138] Synthesis of compound (DA-1) To 3.52 g (10.0 mmol) of compound (DA-1-2), 30 ml each of THF and water were added, and 10 equivalents of tin chloride was added thereto and reacted at 60°C for 2 hours. After the reaction, 50 ml of ethyl acetate was added and the mixture was separated. The mixture was further separated twice with 50 ml of water, and the organic layer was distilled off using a rotary evaporator. The resulting solid was dissolved in 50 ml of THF, and 30 ml of ethanol and 10 ml of water were added thereto. The good solvent was slowly distilled off using a rotary evaporator, and the precipitated solid was collected by filtration and dried to obtain 2.48 g of compound (DA-1).

[0139] [Synthesis Example 1-2] Compound (DA-3) was synthesized according to the following scheme. [ka]

[0140] Synthesis of compound (DA-3-1) A solution of 30.2 g (120 mmol) of triethyl phosphonoacetate in 200 mL of dehydrated THF was added dropwise to 4.8 g (120 mmol) of sodium hydride and stirred at 0°C for 2 hours. A solution of 21.9 g (100 mmol) of 4'-nitro-2,2,2-trifluoroacetophenone in 100 mL of THF was added dropwise, stirred at room temperature for 1 hour, and then refluxed for 2 hours. After the reaction was complete, 300 mL of ethyl acetate was added, and the mixture was separated twice with saturated NH4Cl solution and three times with water. The organic layer was evaporated using a rotary evaporator, and then stirred under reflux with 300 mL of water and 10 g of sodium hydroxide for 3 hours. After stirring, the pH was adjusted to 4 with hydrochloric acid, and the precipitated solid was collected by filtration, washed with water, and dried to obtain 17.7 g of compound (DA-3-1) as an intermediate. Thereafter, compound (DA-3) was synthesized in the same manner as compound (DA-1-2) and compound (DA-1).

[0141] [Synthesis Example 1-3] Compound (DA-4) was synthesized according to the following scheme. [ka]

[0142] Synthesis of compound (DA-4-2) 2.51 g (10.0 mmol) of compound (DA-4-1), 3.85 g (50.0 mmol) of ammonium acetate, and 4.65 g (50.0 mmol) of aniline were added to 100 mL of ethanol and allowed to react under reflux for 3 hours. After the reaction, the solvent was removed using a rotary evaporator, and the mixture was dissolved in 50 mL of ethyl acetate and 50 mL of THF. The mixture was then separated three times with 1 N hydrochloric acid and three times with water. After the organic layer was removed, the mixture was stirred under reflux with 100 mL of water and 3 g of sodium hydroxide for 3 hours. After stirring, the pH was adjusted to 4 with hydrochloric acid, and the precipitated solid was collected by filtration, washed with water, and dried to obtain 2.76 g of compound (DA-4-2) as an intermediate. Thereafter, compound (DA-4) was synthesized in the same manner as compound (DA-1-2) and compound (DA-1).

[0143] [Synthesis Example 1-4] Compound (M-1) was synthesized according to the following scheme. [ka]

[0144] Synthesis of compound (M-1-2) 31.0 g (100 mmol) of compound (M-1-1), 76.0 g (500 mmol) of DBU, 87.8 mg (2.50 mmol) of Pd(PPh3)2Cl2, and 2.130 g (10.0 mmol) of 1,4-bis(diphenylphosphino)butane were dissolved in 200 ml of DMSO under a nitrogen atmosphere. Next, 7.01 g (100 mmol) of propiolic acid was added and the mixture was allowed to react at 50 °C for 5 hours. The reaction solution was then poured into 200 ml of ethyl acetate and separated twice with 200 ml of saturated sodium bicarbonate solution, twice with 200 ml of 1 N hydrochloric acid, and three times with 200 ml of water. The organic layer was distilled under reduced pressure to obtain 21.7 g of compound (M-1-2).

[0145] Synthesis of compound (M-1-3) 3.00 g (10.1 mmol) of compound (M-1-2) was dissolved in 100 ml of dichloromethane and ice-cooled to 0°C. Next, 9 g of 47.0-49.0% hydrobromic acid was added and allowed to react for 5 hours. The reaction solution was slowly poured into saturated aqueous sodium hydroxide solution and separated. The solution was further separated twice with 50 ml of 1 N hydrochloric acid and twice with 100 ml of water, and the organic layer was distilled under reduced pressure. The resulting solid was purified by column chromatography to obtain 1.68 g of compound (M-1-3).

[0146] Synthesis of compound (M-1) 1.13 g (3.00 mmol) of compound (M-1-3) was added to 10 ml of thionyl chloride and a catalytic amount of DMF, and the mixture was reacted at 60°C for 2 hours. After the reaction, thionyl chloride was removed by distillation under reduced pressure. The resulting solid was dissolved in 20 ml of dehydrated THF to give solution A. Separately from solution A, 0.391 g (3.00 mmol) of 2-hydroxyethyl methacrylate and 0.500 g of triethylamine were dissolved in 10 ml of dehydrated THF and ice-cooled to 0°C. Solution A was added dropwise to the mixture, and the mixture was allowed to react overnight at room temperature. After the reaction, the reaction solution was separated twice with 1 N hydrochloric acid and three times with water, and the organic layer was removed by distillation under reduced pressure. The resulting viscous material was purified by column chromatography to give 1.03 g of compound (M-1).

[0147] [Synthesis Example 1-5] Compound (M-2) was synthesized according to the following scheme. [ka]

[0148] Synthesis of compound (M-2-2) Compound (M-2-2) was synthesized in the same manner as compound (DA-3-1), except that the raw materials were changed.

[0149] Synthesis of compound (M-2) 20 ml of thionyl chloride and a catalytic amount of DMF were added to 3.70 g (10.0 mmol) of compound (M-2-2) and reacted at 60 °C for 2 hours. After the reaction, thionyl chloride was removed by distillation under reduced pressure. The resulting solid was dissolved in 50 ml of dehydrated THF to give solution A. 1.90 g (10.0 mmol) of 4-hydroxyphenylmaleimide and 1.20 g of triethylamine were dissolved in 50 ml of dehydrated THF and cooled to 0 °C on ice. Solution A was added dropwise to the mixture and reacted overnight at room temperature. After the reaction, the reaction solution was separated twice with 1 N hydrochloric acid and three times with water, and the organic layer was removed by distillation under reduced pressure. The resulting solid was then dissolved in 50 ml of THF, and 30 ml of ethanol and 10 ml of water were added. The good solvent was slowly removed by distillation using a rotary evaporator, and the precipitated solid was collected by filtration and dried to obtain 3.31 g of compound (M-2).

[0150] [Synthesis Example 1-6] Compound (M-3) was synthesized according to the following scheme. [ka]

[0151] Synthesis of compound (M-3-2) The methyl ester of compound (M-3-2) was synthesized in the same manner as in J. Am. Chem. Soc. 2001, 123, 40, 9918-9919, and then hydrolyzed in the same manner as in compound (DA-1-1) to obtain compound (M-3-2). The subsequent steps were the same as in compound (M-2).

[0152] [Synthesis Examples 1-7 and 1-8] Compounds (M-4) and (M-5) were synthesized in the same manner as compound (M-2), except that the raw materials were changed. [ka] [ka]

[0153] [Synthesis Example 1-9] Compound (M-6) was synthesized according to the following scheme. [ka]

[0154] Synthesis of compound (M-6-1) Compound (M-1-1) 15.46 g (50.0 mmol), methyl methacrylate 16.0 ml (150.0 mmol), P(o-tolyl) 31.52 g (5.00 mmol), iPrNEt 26.1 ml (150 mmol), palladium acetate 561 mg (2.50 mmol), and DMF 250 ml were added and thoroughly purged with nitrogen. The mixture was heated to 100 °C and reacted for 6 hours. After confirming the disappearance of the raw materials by LC, the mixture was cooled to room temperature. After cooling, 200 ml of ethyl acetate was added, stirred at room temperature for a while, and the precipitate was removed by filtration. 200 ml of hexane was added to the filtrate, and the mixture was washed twice with 100 ml of 1N HCl, twice with 100 ml of distilled water, and once with 100 ml of saturated saline. The organic layer was dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure using a rotary evaporator and oil pump. The resulting solid was stirred under reflux with 300 ml of water and 5 g of sodium hydroxide for 3 hours. After stirring, the pH was adjusted to 4 with hydrochloric acid, and the precipitated solid was collected by filtration, washed with water, and dried to obtain 17.2 g of compound (DA-6-2) as an intermediate. Compound (M-6) was then synthesized in the same manner as compound (M-2).

[0155] [Synthesis Example 1-10] Compound (M-7) was synthesized in the same manner as compound (M-6), except that the raw materials were changed. [ka]

[0156] 2. Polymer synthesis <Synthesis of polyamic acid> [Synthesis Example 2-1] 50 parts by mole of 2,3,5-tricarboxycyclopentylacetic dianhydride (compound (T-1)), 50 parts by mole of 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 70 parts by mole of compound (DA-1), and 30 parts by mole of compound (DA-2) were dissolved in N-methyl-2-pyrrolidone (NMP), and the mixture was allowed to react at 40°C for 3 hours to obtain a solution containing 10% by mass of polymer (P-1).

[0157] [Synthesis Examples 2-4, 2-11, 2-12 and 2-13, Comparative Synthesis Examples 3 and 4] Solutions containing polymers (P-10), (PAA-S), (PAA-1), (PAA-2), (P-13), and (P-14) were obtained by the same procedure as in Synthesis Example 2-1 above, except that the types and amounts of tetracarboxylic acid derivatives and diamines used were changed as shown in Table 1 below. In Table 1, the numerical values ​​for tetracarboxylic acid derivatives indicate the proportion (mol %) of each compound used relative to the total amount of tetracarboxylic acid derivatives used in synthesizing the polymers. The numerical values ​​for diamines indicate the proportion (mol %) of each compound used relative to the total amount of diamines used in synthesizing the polymers.

[0158] <Synthesis of Polyimide> [Synthesis Example 2-2] 100 moles of 2,3,5-tricarboxycyclopentylacetic dianhydride (compound (T-1)), 20 moles of compound (DA-2), and 80 moles of compound (DA-3) were dissolved in N-methyl-2-pyrrolidone (NMP) and reacted at 40°C for 3 hours to obtain a solution containing 10% by mass of polyamic acid. Pyridine and acetic anhydride were added to the resulting polyamic acid solution in an amount of 1 mole per mole of tetracarboxylic dianhydride used in the polymerization, and a dehydration ring-closing reaction was carried out at 100°C for 8 hours. After the reaction was completed, the reaction mixture was poured into a large excess of methanol to precipitate the reaction product. The recovered precipitate was washed with methanol and then dried under reduced pressure at 40°C for 15 hours to obtain polymer (P-2). The imidization rate of the resulting polymer (P-2) was 68%.

[0159] <Synthesis of polyamic acid ester> [Synthesis Example 2-3] A 200 mL three-neck flask equipped with a nitrogen inlet tube, reflux condenser, and thermometer was charged with 22.42 g of a compound represented by the following formula (TA-3), 100 mL of tetrahydrofuran, and 0.79 g of pyridine, and the mixture was stirred under a nitrogen stream to form a suspension. 15.14 g of β-methallyl alcohol was added to this suspension, and the mixture was stirred at room temperature for 2 hours. The reaction was further carried out at 60°C for 8 hours, yielding a colorless, transparent solution. The reaction solution was concentrated under reduced pressure at 60°C and further dried in vacuo to obtain 36.84 g of a mixture of a compound represented by the following formula (DE-1a) and a compound represented by the following formula (DE-1b) (hereinafter referred to as "mixture (DE-1a / b)"). [ka]

[0160] Next, 18.42 g of the mixture (DE-1a / b) and 100 mL of toluene were placed in a 100 mL recovery flask equipped with a nitrogen inlet tube and a reflux condenser, and the mixture was stirred at 80 °C for 30 minutes. The mixture was then cooled to room temperature with stirring and further stirred at room temperature for 30 minutes. The resulting suspension was filtered and washed twice with 5 mL of toluene. The resulting solid was dried under vacuum at 60 °C, yielding 15.47 g of compound (DE-1a) as a white powder (84% yield).

[0161] A 500 mL three-neck flask equipped with a nitrogen inlet tube, reflux condenser, and thermometer was charged with 14.74 g of compound (DE-1a), 80 mL of heptane, and 0.032 g of pyridine, and the mixture was stirred at 75°C under a nitrogen stream. 14.28 g of thionyl chloride was slowly added dropwise over 20 minutes, and foaming was observed as the reaction proceeded. After the addition was completed, the mixture was reacted at 75°C for 2 hours to obtain a colorless, transparent solution. The reaction solution was concentrated under reduced pressure at 60°C, and excess thionyl chloride was distilled off. 80 mL of heptane was added to the resulting liquid, which was stirred at room temperature. The precipitated insoluble matter was removed by filtration. The filtrate was concentrated under reduced pressure at 60°C and further dried under high vacuum at 60°C for 4 hours to obtain 15.89 g of the compound represented by the following formula (DE-1a) as a colorless, transparent liquid (yield: 98%). [ka]

[0162] A 50 mL three-neck flask equipped with a nitrogen inlet tube and a thermometer was charged with 100 mol parts of compound (T-3), 70 mol parts of compound (DA-2), 30 mol parts of compound (DA-4), 57 g of NMP, and 24 g of triethylamine. The mixture was cooled to approximately 10°C, and 83 g of a triazine-based dehydration condensation agent, DMT-MM, was added. The reaction was allowed to proceed at room temperature for 24 hours under a nitrogen stream. The resulting polymerization solution was diluted with NMP and slowly poured into methanol with stirring to allow coagulation. The precipitated solid was collected, washed twice in methanol with stirring, and vacuum dried at 60°C to obtain a white powder polyamic acid ester (hereinafter referred to as "polymer (P-3)"). The number-average molecular weight (Mn) of this polymer was 14,000, and the molecular weight distribution (Mw / Mn) was 2.8.

[0163] [Table 1]

[0164] <Synthesis of Polyorganosiloxane> [Synthesis Example 2-5] 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine were mixed at room temperature in a reaction vessel equipped with a stirrer, thermometer, dropping funnel, and reflux condenser. Next, 100 g of pure water was slowly added dropwise, followed by stirring at 80°C for 6 hours. The organic layer was then removed and washed with 0.2% by weight ammonium nitrate aqueous solution until the water became neutral, after which it was concentrated to obtain epoxy-containing polyorganosiloxane (EPS-1) as a viscous, transparent liquid. The Mw of this epoxy-containing polyorganosiloxane (EPS-1) was 2,200 and the epoxy equivalent was 186 g / mol. Next, 8.0 g of the epoxy group-containing polyorganosiloxane (EPS-1) obtained above, 26 g of methyl isobutyl ketone, 15.3 g of compound (CA-1), and 0.10 g of "UCAT 18X" (a quaternary amine salt manufactured by San-Apro Co., Ltd.) were charged into a 100 mL three-neck flask and reacted at 80 ° C for 12 hours with stirring. After the reaction was completed, the reaction mixture was poured into methanol and the resulting precipitate was collected. This precipitate was dissolved in ethyl acetate to form a solution. The solution was washed with water three times, and the solvent was then distilled off to obtain 23.2 g of polymer (P-4) as a white powder. The weight average molecular weight (Mw) of this polymer (P-4) was 14,100.

[0165] <Synthesis of addition polymer> [Synthesis Example 2-6] Under nitrogen, 9.0 g of compound (M-1), 3.0 g of compound (M-9), and 1.8 g of compound (M-10) were added to a 100 mL two-neck flask as polymerization monomers, 0.70 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, 0.20 g of 2,4-diphenyl-4-methyl-1-pentene as a chain transfer agent, and 50 mL of N-methyl-2-pyrrolidone (NMP) as a solvent. The mixture was polymerized at 70 °C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and dried under vacuum at room temperature for 8 hours to obtain the target polymer (P-5). The weight-average molecular weight (Mw) measured by GPC (polystyrene equivalent) was 42,000, and the molecular weight distribution (Mw / Mn) was 2.1.

[0166] [Synthesis Examples 2-7 to 2-10, Comparative Synthesis Examples 1, 2, and 5] Polymers (P-6) to (P-9), (P-11), (P-12), and (P-15) were obtained by the same procedure as in Synthesis Example 2-6 above, except that the types and amounts of the polymerizable monomers used were changed as shown in Table 2. In Table 2, the numerical values ​​for the polymerizable monomers indicate the proportion (mol %) of each compound used relative to the total amount of the polymerizable monomers used in the synthesis of the polymer.

[0167] [Table 2]

[0168] 3. Production and evaluation of liquid crystal alignment agents and liquid crystal display devices [Example 1] (1) Preparation of liquid crystal alignment agent To a container containing 5 parts by mass of the polymer (P-1) obtained in Synthesis Example 2-1, 100 parts by mass of the polymer (PAA-1) obtained in Synthesis Example 2-12, and 10 parts by mass of the compound (ADD-1), NMP and butyl cellosolve (BC) were added as solvents to prepare a solution with a solvent composition of NMP / BC = 50 / 50 (mass ratio) and a solids concentration of 3.5 mass%. This solution was filtered through a filter with a pore size of 1 μm to prepare a liquid crystal alignment agent (AL-1).

[0169] (2) Manufacturing of optical FFS type liquid crystal display elements A glass substrate was prepared that had two sets of metal electrodes (electrode A and electrode B) made of chromium patterned in a comb-like shape, allowing voltage to be applied independently to electrode A and electrode B. This glass substrate was paired with an opposing glass substrate that had no electrodes, and the liquid crystal alignment agent (AL-1) prepared above was applied to the electrode side of the glass substrate and one side of the opposing glass substrate using a spin coater. Next, the substrate was pre-baked for 1 minute on a hot plate at 80°C, and then heated (post-baked) for 1 hour in an oven at 200°C with the interior replaced with nitrogen, forming a coating film with an average thickness of 0.08 μm. This procedure was repeated to obtain a pair (two sheets) of glass substrates having a coating film on the transparent conductive film. The coating film obtained above was irradiated with 2,000 J / m of polarized ultraviolet light containing a 313 nm emission line using an Hg-Xe lamp and a Glan-Taylor prism. 2 The amount of irradiation was measured using an actinometer measuring at a wavelength of 313 nm. Next, for one of the pair of substrates on which the liquid crystal alignment film was formed, an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was applied to the outer edge of the surface bearing the liquid crystal alignment film, and the pair of substrates were then overlapped with each other so that the liquid crystal alignment film surfaces faced each other and pressed together, and the adhesive was allowed to harden. Next, a liquid crystal composition (MLC-6221, manufactured by Merck) was filled between the pair of substrates through the liquid crystal injection port, and the liquid crystal injection port was sealed with an acrylic photocurable adhesive to obtain a liquid crystal cell. Furthermore, polarizing plates were attached to both outer surfaces of the substrates in the liquid crystal cell so that the polarization directions of the two polarizing plates were perpendicular to each other.

[0170] (3) Backlight reliability (BL reliability) evaluation The liquid crystal display device fabricated above was tested at 27,000 cd / m 2 The device was left standing for 500 hours in front of a high-intensity backlight, and the change in characteristics before and after irradiation with the backlight was evaluated by the method (3A) below. (3A) Evaluation of BL reliability by retardation change rate The retardation of the liquid crystal display element was measured using an Axoscan manufactured by Optoscience, and the change rate α of retardation before and after backlight irradiation was calculated using the following formula (z-1). The smaller the change rate α, the less likely the liquid crystal display element is to have an afterimage even after long-term operation, and the better the BL reliability. A change rate α of 0.5% or less was rated "best (◎)," a change rate of more than 0.5% and less than 1% was rated "good (○)," a change rate of more than 1% and less than 2% was rated "fair (△)," and a change rate of more than 2% was rated "poor (×)." α=Δθ / θ1 …(z-1) (In formula (z-1), Δθ represents the difference in retardation before and after irradiation, and θ1 represents the retardation before irradiation.) As a result, this example was evaluated as "good (◯)".

[0171] [Examples 2 and 3 and Comparative Example 3] Each liquid crystal alignment agent was prepared in the same manner as in Example 1, except that the formulation of the liquid crystal alignment agent was changed as shown in Table 3. In addition, using the prepared liquid crystal alignment agent, an optical FFS type liquid crystal display element was manufactured in the same manner as in Example 1, and evaluations were performed in the same manner as in Example 1. The results are shown in Table 3.

[0172] [Example 4] (1) Preparation of liquid crystal alignment agent To a container containing 50 parts by mass of the polymer (P-4) obtained in Synthesis Example 2-5, 100 parts by mass of the polymer (PAA-1) obtained in Synthesis Example 2-12, and 5 parts by mass of the compound (ADD-4), NMP and butyl cellosolve (BC) were added as solvents to prepare a solution with a solvent composition of NMP / BC = 50 / 50 (mass ratio) and a solids concentration of 3.5 mass%. This solution was filtered through a filter with a pore size of 1 μm to prepare a liquid crystal alignment agent (AL-4).

[0173] (2) Manufacturing of optical vertical LCD display elements (UV2A) The liquid crystal alignment agent (AL-4) prepared in (1) above was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a spinner, prebaked on a hot plate at 80°C for 1 minute, and then baked at 200°C for 40 minutes to form a coating film with a thickness of 0.08 μm. Next, polarized ultraviolet light of 200 J / m containing a 313 nm emission line was irradiated onto the surface of this coating film using an Hg-Xe lamp and a Glan-Taylor prism. 2 The light was irradiated at room temperature from a direction tilted by 40° relative to the normal to the substrate. The same procedure was repeated to prepare a pair (two substrates) on which a liquid crystal alignment film was formed. An epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was screen-printed onto the outer periphery of the liquid crystal alignment film-bearing surface of one of the two substrates. The pair of substrates were then placed with the liquid crystal alignment film facing each other. The pair of substrates were then pressed together so that the optical axes of the UV light irradiated on each substrate were antiparallel to the substrate surfaces. The adhesive was then thermally cured at 150°C for 1 hour. Next, a liquid crystal composition (MLC-6608, manufactured by Merck) was filled into the gap between the substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive to obtain a liquid crystal cell. To eliminate flow alignment during liquid crystal injection, the liquid crystal cell was heated to 150°C and then slowly cooled to room temperature. Next, polarizing plates were attached to both outer surfaces of the liquid crystal cell so that their polarization directions were perpendicular to each other and formed a 45° angle with the optical axis of the UV light irradiated during liquid crystal alignment film formation.

[0174] (3) Evaluation of BL reliability The liquid crystal display device fabricated above was tested at 27,000 cd / m 2 The device was left standing for 500 hours in front of a high-intensity backlight, and the change in characteristics before and after irradiation with the backlight was evaluated by the method (3B) below. (3B) Evaluation of BL reliability by tilt return The pretilt angle of the liquid crystal was measured using an Optipro manufactured by Shintech Co., Ltd., and the BL reliability was evaluated by comparing the pretilt angle before and after backlight irradiation. A difference in pretilt angle between before and after irradiation of 0.1 degrees or less was evaluated as "best (◎)," a difference between more than 0.1 degrees and less than 0.5 degrees was evaluated as "good (○)," a difference between more than 0.5 degrees and less than 1.0 degrees was evaluated as "fair (△)," and a difference greater than 1.0 degrees was evaluated as "poor (×)." As a result, this example was evaluated as "fair (△)."

[0175] [Examples 5 to 10 and Comparative Examples 1, 2, 4, and 5] Each liquid crystal alignment agent was prepared in the same manner as in Example 4, except that the formulation of the liquid crystal alignment agent was changed as shown in Table 3. In addition, using the prepared liquid crystal alignment agent, a vertical light type liquid crystal display element was manufactured in the same manner as in Example 4, and evaluations were performed in the same manner as in Example 4. The results are shown in Table 3.

[0176] [Table 3]

[0177] From the above results, in Examples 1 to 10 in which the liquid crystal alignment agent containing the polymer (P) was used, the liquid crystal alignment property was good even after long-term irradiation with backlight, and the BL reliability was excellent. In particular, when the polymer (P) was used as the liquid crystal alignment agent, the R β Example 7, in which a polymer (P-7) in which R is a trimethylsilyl group was blended, β Example 8, in which a polymer (P-8) in which R is an ethyl group was blended, β Example 9, in which a polymer (P-9) in which R is a methyl group was blended, and β In Example 10, which contained a polymer (P-10) in which the .alpha.-methyl group was used, the difference in pretilt angle before and after irradiation with the backlight was small, and the BL reliability was evaluated as good (.largecircle.) or best (.circleincircle.).

[0178] In contrast, the BL reliability was poor in Comparative Examples 1 to 5, which used a liquid crystal alignment agent that did not contain the polymer (P). The reason why the BL reliability could not be evaluated in Comparative Example 5, which used the polymer (P-15) in which an ester group (-COOMe) was introduced at the β-position of the cinnamate structure, is presumed to be due to the influence of decarboxylation of the ester group (-COOMe) by post-baking at high temperatures.

[0179] [Example 11] (1) Preparation of liquid crystal alignment agent A liquid crystal aligning agent (AL-11) was prepared using the polymer (P-9) obtained in Synthesis Example 2-10 with the same composition and preparation method as in Example 9.

[0180] (2) Manufacturing and evaluation of liquid crystal display devices A liquid crystal display device corresponding to Figure 1 was manufactured. First, a TFT substrate having pixel electrodes and a CF substrate having a counter electrode were prepared. Solid electrodes without slits were used as the pixel electrodes of the TFT substrate and the counter electrode of the CF substrate. The liquid crystal alignment agent (AL-11) prepared in (1) above was applied by spin casting to the electrode-positioned surfaces of the TFT substrate and the CF substrate. This was pre-baked at 80°C for 1 minute and then post-baked at 230°C for 40 minutes to achieve a final film thickness of 120 nm. Next, scan exposure was performed on the coating film (liquid crystal alignment film) formed on the TFT substrate. Scan exposure was performed using 313 nm linearly polarized light at 20 mJ / cm2, so that four domains with different alignment orientations of liquid crystal molecules were formed within one pixel, as shown in Figure 2. 2 On the other hand, the liquid crystal alignment film formed on the CF substrate using the liquid crystal alignment agent (AL-11) was not exposed to light.

[0181] Next, nematic liquid crystal with negative dielectric anisotropy was dispensed onto the liquid crystal alignment film-formed surface of the TFT substrate, and a thermosetting epoxy resin was applied as a sealant to the outer edge of the CF substrate. The TFT and CF substrates were then bonded together with their alignment film surfaces facing inward. The epoxy resin was then cured by heating at 130°C for 1 hour to obtain a liquid crystal cell. The transmittance of the resulting liquid crystal cell was measured when driven at 6V AC. The transmittance was calculated by simulation using Expert LCD (LinkGlobal21). The calculation conditions were liquid crystal properties: Δε = 3, Ne = 1.6, No = 1.5, cell gap: 3.2μm, and pretilt angle: measured values ​​(TFT substrate side: 88.0°, CF substrate side: 90.0°). The transmittance was evaluated from the results obtained at an applied voltage of 6V. When the calculated transmittance was less than 0.275, it was evaluated as "Fair (△)", when it was 0.275 or more and less than 0.280, it was evaluated as "Good (○)", when it was 0.280 or more and less than 0.285, it was evaluated as "Excellent (◎)", and when it was 0.285 or more, it was evaluated as "Best (◎◎)". 2The change in characteristics (BL reliability due to tilt return) before and after irradiation with the backlight was evaluated by the method described above in (3B). The results are shown in Table 4.

[0182] [Comparative Example 6 and Reference Example 1] Each liquid crystal alignment agent was prepared in the same manner as in Example 11, except that the polymer used was changed as shown in Table 4. In addition, using the prepared liquid crystal alignment agent, a liquid crystal display device was manufactured in the same manner as in Example 11, and the same evaluation as in Example 11 was performed. The results are shown in Table 4.

[0183] [Table 4]

[0184] As shown in Table 4, Example 11, which used a liquid crystal alignment agent containing polymer (P), had high transmittance and excellent BL reliability. In contrast, Comparative Example 6, which used a liquid crystal alignment agent not containing polymer (P), had transmittance and BL reliability inferior to those of Example 11. Furthermore, Reference Example 1, which used a polymer containing a partial structure having a substituent (methyl group) at the α-position instead of the β-position of the carbonyl carbon in the above formula (1), was evaluated as "◎" for transmittance and "○" for BL reliability based on tilt return. These results demonstrate that a liquid crystal alignment agent containing polymer (P) can further improve the transmittance and BL reliability of liquid crystal display devices. [Explanation of symbols]

[0185] 10...liquid crystal display device, 11...first substrate, 12...second substrate, 13...liquid crystal layer, 14...transparent substrate, 15...pixel electrode, 16...transparent substrate, 17...black matrix, 18...color filter, 19...counter electrode, 22...first alignment film, 23...second alignment film, 24...spacer, 25...sealing material, 30...pixel, 31...first domain, 32...second domain, 33...third domain, 34...fourth domain, 35...liquid crystal molecule, 36...wiring

Claims

1. A liquid crystal aligning agent comprising a polymer (P) having a partial structure represented by the following formula (1): 【Chemistry 1】 (In formula (1), R β represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, a cyano group, a nitro group, a chlorine atom, a bromine atom, an iodine atom, or —SiR ２ R ３ R ４ , -P(=O)R ２ R ３ , -C≡CR ２ Or -NR ２ R ３ or any methylene group in the monovalent hydrocarbon group having 2 to 10 carbon atoms is —O—, —S—, or —NR ２ a monovalent group R substituted with - ω１ or a group R ω１ Alternatively, it is a monovalent group in which any hydrogen atom of a monovalent hydrocarbon group having 1 to 10 carbon atoms has been substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group. α represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, a cyano group, a nitro group, a halogen atom, or —SiR ２ R ３ R ４ , -P(=O)R ２ R ３ , -COOR ２ , -C≡CR ２ Or -NR ２ R ３ or any methylene group in the monovalent hydrocarbon group having 2 to 10 carbon atoms is —O—, —S—, or —NR ２ a monovalent group R substituted with - ω２ or a group R ω２ Alternatively, it is a monovalent group in which any hydrogen atom of a monovalent hydrocarbon group having 1 to 10 carbon atoms has been substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group. ２ , R ３ , and R ４ are each independently a hydrogen atom or a monovalent organic group. １ represents an oxygen atom or -NR ５ - is. R ５ is a hydrogen atom or a monovalent organic group. １ is a substituent. n is an integer of 0 to 4. m is 0 or 1. "*" represents a bond.

2. The liquid crystal aligning agent according to claim 1 , wherein the polymer (P) has a partial structure represented by the above formula (1) in a side chain.

3. The liquid crystal aligning agent according to claim 2, wherein the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer.

4. The liquid crystal aligning agent according to claim 1, wherein the polymer (P) has a partial structure represented by the above formula (1) in the main chain.

5. The liquid crystal aligning agent according to claim 4, wherein the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

6. The liquid crystal aligning agent according to claim 1, wherein the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer.

7. The R α represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, or a monovalent hydrocarbon group having 2 to 10 carbon atoms, in which any methylene group is -O-, -S-, or -NR ２ -substituted monovalent group (wherein R ２ The liquid crystal aligning agent according to claim 1, wherein

8. The R β represents an alkyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, a trialkylsilyl group, a cyano group, a bromine atom, an iodine atom, -NR １２ R １３ (However, R １２ and R １３ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, or any methylene group in the monovalent hydrocarbon group having 2 to 10 carbon atoms is —O—, —S—, or —NR ２ -substituted monovalent group (wherein R ２ The liquid crystal aligning agent according to claim 1, wherein

9. The liquid crystal aligning agent according to claim 1, further comprising a polymer (Q) that does not have the partial structure represented by the formula (1).

10. The liquid crystal aligning agent according to claim 9, wherein the polymer (Q) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, and addition polymer.

11. A method for producing a liquid crystal alignment film, comprising: a step of applying the liquid crystal aligning agent according to any one of claims 1 to 10 onto a substrate to form a coating film; and a step of irradiating the coating film with light.

12. A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of claims 1 to 10.

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

14. A liquid crystal display device having a plurality of pixels, a first substrate; a second substrate facing the first substrate; a liquid crystal layer provided between the first substrate and the second substrate and containing liquid crystal molecules; a first alignment film formed on the first substrate to align the liquid crystal molecules; a second alignment film formed on the second substrate to align the liquid crystal molecules; Equipped with at least one of the first alignment film and the second alignment film is a photo-alignment film; Each pixel among the plurality of pixels has a first alignment region, a second alignment region, a third alignment region, and a fourth alignment region as regions in which the alignment orientations of the liquid crystal molecules are different from one another, and the first alignment region, the second alignment region, the third alignment region, and the fourth alignment region are arranged side by side in a longitudinal direction of the pixel, a difference between any two of the orientation orientation of the first orientation region, the orientation orientation of the second orientation region, the orientation orientation of the third orientation region, and the orientation orientation of the fourth orientation region is approximately equal to an integer multiple of 90 degrees; the plurality of pixels are arranged side by side in a short-side direction of the pixels such that the alignment directions of the alignment regions adjacent to each other in the short-side direction of the pixels are the same; in each of the first alignment region, the second alignment region, the third alignment region, and the fourth alignment region, one of a pretilt angle defined by the first alignment film and a pretilt angle defined by the second alignment film is less than 90 degrees, and the other is substantially 90 degrees; A liquid crystal display device, wherein the photo-alignment film is formed using the liquid crystal aligning agent according to any one of claims 1 to 8.

15. A polymer having a partial structure represented by the following formula (1): 【Chemistry 2】 (In formula (1), R β represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, a cyano group, a nitro group, a chlorine atom, a bromine atom, an iodine atom, or —SiR ２ R ３ R ４ , -P(=O)R ２ R ３ , -C≡CR ２ Or -NR ２ R ３ or any methylene group in the monovalent hydrocarbon group having 2 to 10 carbon atoms is —O—, —S—, or —NR ２ a monovalent group R substituted with - ω１ or a group R ω１ Alternatively, it is a monovalent group in which any hydrogen atom of a monovalent hydrocarbon group having 1 to 10 carbon atoms has been substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group. α represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, a cyano group, a nitro group, a halogen atom, or —SiR ２ R ３ R ４ , -P(=O)R ２ R ３ , -COOR ２ , -C≡CR ２ Or -NR ２ R ３ or any methylene group in the monovalent hydrocarbon group having 2 to 10 carbon atoms is —O—, —S—, or —NR ２ a monovalent group R substituted with - ω２ or a group R ω２ Alternatively, it is a monovalent group in which any hydrogen atom of a monovalent hydrocarbon group having 1 to 10 carbon atoms has been substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group. ２ , R ３ , and R ４ are each independently a hydrogen atom or a monovalent organic group. １ represents an oxygen atom or -NR ５ - is. R ５ is a hydrogen atom or a monovalent organic group. １ is a substituent. n is an integer of 0 to 4. m is 0 or 1. "*" represents a bond.

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