Liquid crystal alignment agent, liquid crystal alignment film and method for producing the same, liquid crystal element, liquid crystal display device, and polymer

Abstract

This invention provides a liquid crystal alignment agent with minimal change in liquid crystal alignment even after prolonged backlighting, a liquid crystal alignment film, a method for manufacturing the same, a liquid crystal element, a liquid crystal display device, and a polymer. The liquid crystal alignment agent contains a polymer (P) having a partial structure represented by formula (1). Wherein, R... β Monovalent hydrocarbon groups, cyano groups, nitro groups, chlorine atoms, bromine atoms, iodine atoms, and -SiR groups with 1 to 10 carbon atoms 2 R 3 R 4 -P(=O)R 2 R 3 、-C≡CR 2 or -NR 2 R 3 Any methylene group in a monovalent hydrocarbon group having 2 to 10 carbon atoms is prefixed with -O-, -S-, or -NR. 2 - The monovalent base R formed by substitution ω1 ; or base R ω1 Or a monovalent hydrocarbon group having 1 to 10 carbon atoms, formed by substitution of any hydrogen atom with a halogen atom, cyano group, hydroxyl group, amino group, thiol group, or nitro group. R α It consists of hydrogen atoms, monovalent hydrocarbon groups with 1 to 10 carbon atoms, etc.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid crystal alignment agent, a liquid crystal alignment film and a manufacturing method thereof, a liquid crystal element, a liquid crystal display device, and a polymer. BACKGROUND

[0002] In a liquid crystal element, a liquid crystal alignment film is used in order to control the alignment of liquid crystal molecules in a liquid crystal layer. The liquid crystal alignment film is generally formed using a liquid crystal alignment agent containing a polymer component. As a method of obtaining an organic film having a liquid crystal alignment restricting force, a method of rubbing an organic film, a method of oblique vapor deposition of silicon oxide, and a method of forming a monomolecular film having a long-chain alkyl group are known, in addition to a method of light irradiation of a photosensitive organic film (photo-alignment method) and the like.

[0003] The photo-alignment method can impart a liquid crystal alignment to a film uniformly while suppressing the generation of static electricity or dust, and thus various studies have been made in recent years (for example, refer to Patent Literature 1 and Patent Literature 2). In Patent Literature 1 and Patent Literature 2, a case where a liquid crystal alignment film is formed using a polymer having a cinnamate structure by the photo-alignment method is disclosed.

[0004] [Prior Art Documents]

[0005] [Patent Literature]

[0006] [Patent Literature 1] International Publication No. 2007 / 071091

[0007] [Patent Literature 2] International Publication No. 2016 / 080033 SUMMARY

[0008] [Problems to be Solved by the Invention]

[0009] The liquid crystal alignment film obtained by the photo-alignment treatment (photo-alignment film) has a tendency that the alignment restricting force of the liquid crystal molecules is not sufficient compared to the case where a rubbing treatment is performed. Therefore, if the liquid crystal element is driven for a long time, sometimes a change in the retardation due to the long-time backlight irradiation is seen, or the direction of the initial alignment of the liquid crystal gradually shifts from the original at the time of manufacture. Such a change in the alignment has a concern that it is expressed as a burn-in (image sticking) of an image or a reduction in the transmittance, a reduction in the black luminance. As a liquid crystal element, in order to meet the requirement for higher performance in recent years, it is desired to further improve the display quality.

[0010] The present application was made in view of the above-described problems, and its main object is to provide a liquid crystal element in which a change in the liquid crystal alignment is small even after a long-time backlight irradiation, and the reliability is high.

[0011] [Technical Means to Solve the Problems]

[0012] The following means are provided according to the present application.

[0013] <1> A liquid crystal aligning agent comprising a polymer (P) having a partial structure represented by the following formula (1).

[0014] [Chemical Formula 1]

[0015]

[0016] (In formula (1), R β 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, -SiR 2 R 3 R 4 , -P(=O)R 2 R 3 , -C≡CR 2 , or -NR 2 R 3 ; any methylene group in a monovalent hydrocarbon group having 2 to 10 carbon atoms is substituted with -O-, -S-, or -NR 2 ; or a monovalent group R ω1 substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group. ω1 R α is a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, a cyano group, a nitro group, a halogen atom, -SiR 2 R 3 R 4 , -P(=O)R 2 R 3 , -COOR 2 , -C≡CR 2 , or -NR 2 R 3 ; any methylene group in a monovalent hydrocarbon group having 2 to 10 carbon atoms is substituted with -O-, -S-, or -NR 2 ; or a monovalent group R ω2 substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group, or a nitro group. ω2 R 2 , R 3 , and R 4 are each independently a hydrogen atom or a monovalent organic group. X 1 is an oxygen atom or -NR 5 . R 5 is a hydrogen atom or a monovalent organic group. R 1 is a substituent. n is an integer of 0 to 4. m is 0 or 1. "*" represents a bond.)

[0017] <2> A method for manufacturing a liquid crystal alignment film includes: a step of coating a liquid crystal alignment agent according to <1> onto a substrate to form a coating film; and a step of irradiating the coating film with light.

[0018] <3> A liquid crystal alignment film, formed using the liquid crystal alignment agent according to <1>.

[0019] <4> A liquid crystal element comprising a liquid crystal alignment film according to <3>.

[0020] <5> A liquid crystal display device is disclosed, which is a liquid crystal display device having multiple pixels, and includes: a first substrate; a second substrate facing the first substrate; a liquid crystal layer disposed between the first substrate and the second substrate and containing liquid crystal molecules; a first alignment film formed on the first substrate and aligning the liquid crystal molecules; and a second alignment film formed on the second substrate and 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 photoalignment film. Each pixel in the plurality of pixels has a first alignment region, a second alignment region, a third alignment region, and a fourth alignment region as regions where the orientations of the liquid crystal molecules are different from each other. The first alignment region, the second alignment region, the third alignment region, and the fourth alignment region are arranged along the long side direction of the pixel. The difference between any two orientations of the first alignment region, the second alignment region, the third alignment region, and the fourth alignment region is approximately equal to an integer multiple of 90 degrees. The plurality of pixels are arranged along the short side direction of the pixel such that the orientations of the adjacent alignment regions in the short side direction of the pixel are the same. In each alignment region of the first alignment region, the second alignment region, the third alignment region, and the fourth alignment region, one of the pretilt angles defined by the first alignment film and the pretilt angle defined by the second alignment film is less than 90 degrees, and the other is substantially 90 degrees. The photoalignment film is formed using a liquid crystal alignment agent according to <1>.

[0021] <6> An aggregate having a partial structure represented by the formula (1).

[0022] [The effects of the invention]

[0023] Based on the above structure, a liquid crystal element with low change in liquid crystal orientation and high reliability can be obtained even after long-term backlight irradiation. Attached Figure Description

[0024] Figure 1Fig. 1 is a schematic view showing an outline structure of a liquid crystal display device.

[0025] Figure 2 Fig. 1 (a) to (c) are views showing an example of an alignment pattern in a pixel of a liquid crystal display device. Figure 2 Fig. 1 (c) is a view showing an example of an alignment pattern in a pixel of a liquid crystal display device.

[0026] Figure 3 Fig. 1 (a) and (b) are views showing an example of an alignment pattern in a pixel of a liquid crystal display device. Figure 3 Fig. 1 (b) is a view showing an example of an alignment pattern in a pixel of a liquid crystal display device. (a) shows a first substrate, and (b) shows a second substrate.

[0027] [Explanation of symbols]

[0028] 10: Liquid crystal display device

[0029] 11: First substrate / substrate

[0030] 12: Second substrate / substrate

[0031] 13: Liquid crystal layer

[0032] 14: Transparent substrate

[0033] 15: Pixel electrode

[0034] 16: Transparent substrate

[0035] 17: Black matrix

[0036] 18: Color filter

[0037] 19: Counter electrode

[0038] 22: First alignment film

[0039] 23: Second alignment film

[0040] 24: Spacer

[0041] 25: Sealing material

[0042] 30: Pixel

[0043] 31: First domain / domain

[0044] 32: Second domain / domain

[0045] 33: Third domain / domain

[0046] 34: Fourth domain / domain

[0047] 35: Liquid crystal molecule

[0048] 36: Wiring / signal line

[0049] 37, 41: Arrow

[0050] 44: Corresponding region of the fourth domain

[0051] X, Y: Direction Detailed Implementation

[0052] The following provides a detailed description of matters related to the form disclosed herein. Furthermore, in this specification, the term "hydrocarbon group" encompasses chain-like hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Chain-like hydrocarbon group" refers to a straight-chain hydrocarbon group or branched hydrocarbon group that does not contain a cyclic structure but is composed solely of a chain structure. It can be saturated or unsaturated. "Alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as its ring structure and does not contain an aromatic ring structure. It is not necessary for it to be composed solely of an alicyclic hydrocarbon structure; it may also include groups with a chain structure in a portion thereof. "Aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as its ring structure. It is not necessary for it to be composed solely of an aromatic ring structure; it may also include a chain structure or an alicyclic hydrocarbon structure in a portion thereof.

[0053] The term "aliphatic hydrocarbon group" refers to both chain-like and alicyclic hydrocarbon groups. The "main chain" of a polymer refers to the longest segment of its atomic chain. The "side chain" of a polymer refers to the branching segments from the main chain. An "organic group" is a group of atoms formed by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound). "(meth)acrylate" includes both acrylates and methacrylates. "(meth)acrylic acid" includes both acrylic acid and methacrylic acid.

[0054] Liquid crystal alignment agent

[0055] The liquid crystal alignment agent disclosed herein contains a polymer (P) having a partial structure represented by the following formula (1).

[0056] [Chemistry 2]

[0057]

[0058] (In equation (1), R) β Monovalent hydrocarbon groups, cyano groups, nitro groups, chlorine atoms, bromine atoms, iodine atoms, and -SiR groups with 1 to 10 carbon atoms 2 R 3 R 4 -P(=O)R 2 R 3 -C≡CR 2 or -NR 2 R 3 Any methylene group in a monovalent hydrocarbon group having 2 to 10 carbon atoms is designated with -O-, -S-, or -NR. 2 -The monovalent base R formed by substitutionω1 ; or a monovalent group R ω1 substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group or a nitro group. R α is a hydrogen atom, a monovalent hydrocarbon group having a carbon number of 1 to 10, a cyano group, a nitro group, a halogen atom, -SiR 2 R 3 R 4 , -P(=O)R 2 R 3 , -COOR 2 , -C≡CR 2 or -NR 2 R 3 ; a monovalent group R 2 substituted with -O-, -S- or -NR ω2 ; or a monovalent group R ω2 substituted with a halogen atom, a cyano group, a hydroxyl group, an amino group, a thiol group or a nitro group. R 2 , R 3 and R 4 are each independently a hydrogen atom or a monovalent organic group. X 1 is an oxygen atom or -NR 5 -. R 5 is a hydrogen atom or a monovalent organic group. R 1 is a substituent. n is an integer of 0 to 4. m is 0 or 1. "*" indicates a bond. )

[0059] <Polymers (P)>

[0060] The partial structure represented by the formula (1) possessed by the polymers (P) has a substituent (R β ) at the β position of the carbonyl carbon. In the formula (1), as the monovalent hydrocarbon group having a carbon number of 1 to 10 represented by R β , there can be mentioned an alkyl group having a carbon number of 1 to 10, a cycloalkyl group having a carbon number of 3 to 10, an aryl group having a carbon number of 6 to 10, an aralkyl group having a carbon number of 6 to 10, etc.

[0061] The alkyl group having a carbon number of 1 to 10 can be linear or branched, and specifically, there can be mentioned, for example, 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, a decyl group, etc. As the cycloalkyl group having a carbon number of 3 to 10, there can be mentioned, for example, a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, etc. As the aryl group having a carbon number of 6 to 10, there can be mentioned, for example, a phenyl group, a tolyl group, etc. As the aralkyl group having a carbon number of 6 to 10, there can be mentioned, for example, a benzyl group, etc.

[0062] As R βThe group represented is any methylene group in a monovalent hydrocarbon group having 2 to 10 carbon atoms, with -O-, -S-, or -NR. 2 -The monovalent base formed by substitution (R) ω1 Specific examples of this situation include: alkyl groups having 2 to 10 carbon atoms, cycloalkyl groups having 3 to 10 carbon atoms, aryl groups having 6 to 10 carbon atoms, or aralkyl groups having 6 to 10 carbon atoms, wherein one or more methylene groups are represented by -O-, -S-, or -NR. 2 - Substituted base. As a base R ω1 Further specific examples can be listed as: alkoxy, alkoxyalkyl, group having a (poly)alkanediol chain, cycloalkoxy, arylalkoxy, arylalkyloxy, etc.

[0063] In R β When the represented group is a monovalent hydrocarbon group with 1 to 10 carbon atoms, and any hydrogen atom is replaced by a halogen atom, examples of halogen atoms include: fluorine, chlorine, bromine, iodine, etc. As R β Specific examples of monovalent groups represented by the group being formed by substitution of a halogen atom include: trifluoromethyl, perfluoroethyl, 2,2,2-trifluoroethyl, trichloromethyl, bromomethyl, etc.

[0064] As R β The basis represented is basis R. ω1 Specific examples of monovalent groups formed by substituting any hydrogen atom of a monovalent hydrocarbon group having 1 to 10 carbon atoms with cyano, hydroxy, amino, thiol, or nitro groups include: cyanomethyl, aminomethyl, 2-aminoethyl, N-(aminomethyl)methyl, hydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl, hydroxymethyloxymethyl, thiolmethyl, 2-thiolethyl, nitromethyl, etc.

[0065] As R 2 R 3 and R 4 Examples of monovalent organic groups include monovalent hydrocarbon groups with 1 to 10 carbon atoms and alkoxy groups with 1 to 10 carbon atoms. Specific examples of monovalent hydrocarbon groups with 1 to 10 carbon atoms include those related to R... β The group that is the same as the group exemplified in the description of the group. Examples of alkoxy groups having 1 to 10 carbon atoms include: methoxy, ethoxy, propoxy, butoxy, pentoxy, etc.

[0066] In terms of obtaining liquid crystal elements that are not easily degraded even after prolonged exposure to backlight and have high reliability, R β Preferably, the carbon groups are monovalent hydrocarbon groups (1-10), cyano groups, nitro groups, chlorine atoms, bromine atoms, iodine atoms, or -SiR groups. 2 R 3 R 4 -P(=O)R2 R 3 -C≡CR 2 or -NR 2 R 3 Any methylene group in a monovalent hydrocarbon group having 2 to 10 carbon atoms is designated with -O-, -S-, or -NR. 2 -The monovalent base R formed by substitution ω1 ; or base R ω1 Or a monovalent group formed 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, more 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, or -NR. 12 R 13 (where R) 12 and R 13 (Each is independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms), or the carbon-carbon bond between the monovalent hydrocarbon groups having 2 to 10 carbon atoms contains -O-, -S-, or -NR. 2 - a monovalent base (where R is a monovalent base) 2 (It can be a hydrogen atom or a monovalent organic group). Among these, R β Particularly preferred are alkyl groups having 1 to 3 carbon atoms, fluoroalkyl groups having 1 to 3 carbon atoms, trialkylsilyl groups, or -NR groups. 12 R 13 More preferably, it is methyl, ethyl or trialkylsilyl.

[0067] The partial structure represented by formula (1) has a hydrogen atom or substituent at the α-position of the carbonyl carbon. R in formula (1) α It is a monovalent hydrocarbon group with 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 The situation, based on R ω2 The situation and the basis R ω2 Specific examples of monovalent groups formed 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 can be listed along with those of R. β The basis represented is the same as the basis exemplified. As R α Specific examples of halogen atoms include: fluorine, chlorine, bromine, and iodine atoms. As "-COOR"... 2 Specific examples of "" include: alkyloxycarbonyl, cycloalkyloxycarbonyl, aryloxycarbonyl, etc.

[0068] R α The represented group is preferably a hydrogen atom, an alkyl group having 1 to 6 carbons, a cyano group, or any methylene group in a monovalent hydrocarbon group having 2 to 10 carbons which is substituted with -O-, -S-, or -NR 2 - (wherein R 2 is a hydrogen atom or a monovalent organic group), more preferably a hydrogen atom, an alkyl group having 1 to 6 carbons, or a cyano group, and still more preferably a hydrogen atom, an alkyl group having 1 to 3 carbons, or a cyano group.

[0069] In the case where the represented group is -NR 1 , the represented group is -NR 5 - (wherein R 5 is a monovalent organic group). As the monovalent organic group represented by R 5 , a monovalent hydrocarbon group having 1 to 10 carbons and a monovalent thermally detachable group can be given. As a specific example of the case where R 5 is a monovalent hydrocarbon group, an alkyl group having 1 to 6 carbons, a cycloalkyl group having 4 to 10 carbons, an aryl group having 6 to 10 carbons, and an aralkyl group having 6 to 10 carbons, etc. can be given. Of these, an alkyl group having 1 to 6 carbons, a cycloalkyl group, and a phenyl group are preferred, and an alkyl group having 1 to 3 carbons is more preferred. In addition, R 5 may also be a ring structure formed by bonding to other groups and to the nitrogen atom to which R 5 is bonded. As the ring structure, a piperidine structure, a piperazine structure, etc. can be given, for example.

[0070] In the case where R 1 is a monovalent thermally detachable group, the thermally detachable group is preferably a monovalent group which is detached by heating at the time of film formation. As a specific example of the thermally detachable group, a t-butoxycarbonyl group (Boc group), a benzyloxycarbonyl group, a 1, 1-dimethyl-2-haloethyl oxycarbonyl group, an allyloxycarbonyl group, a 2- (trimethylsilyl) ethyloxycarbonyl group, etc. can be given. Of these, a Boc group is particularly preferred in terms of excellent detachability by heat and reduction in the residual amount of the detached structure in the film.

[0071] wherein, in terms of further improvement in the photo-orientation of the partial structure represented by the formula (1), X 15 is preferably an oxygen atom, -NH-, -N (CH3) -, or -NR 15 is a Boc group), and still more preferably an oxygen atom.

[0072] As R 1substituents, for example, the following can be enumerated: an alkyl group having 1 to 5 carbons, an alkoxy group having 1 to 5 carbons, a halogen atom, a hydroxyl group, a carboxyl group, an amino group, a cyano group, an alkylsilyl group, an alkoxy silyl group, an ester group, and the like. n is preferably 0 to 2, more preferably 0 or 1, and further preferably 0. Furthermore, in the case where m is 1, the bonding bond (*) in the formula (1) indicates a bonding bond to other groups (organic groups). In the case where m is 1, the bonding bond (*) in the formula (1) can be bonded to an atom constituting the main chain of the polymer or to an atom constituting the side chain. In the case where m is 0, the partial structure represented by the formula (1) can exist in the terminal portion of the main chain of the polymer or in the terminal portion of the side chain.

[0073] The main skeleton of the polymer (P) is not particularly limited. From the viewpoint of heat resistance or mechanical strength, good affinity with liquid crystals, and the like, the polymer (P) is preferably at least one selected from the group consisting of a polyamic acid, a polyimide, a polyamic acid ester, a polyorganosiloxane, and an addition polymer. The polymer (P) can have the partial structure represented by the formula (1) in the main chain, can have the partial structure in the side chain, or can have the partial structure in both the main chain and the side chain. Hereinafter, preferred examples of the polymer (P) will be described.

[0074] [Polyamic acid]

[0075] The polyamic acid (hereinafter, also referred to as "polyamic acid (P)") as the polymer (P) can be obtained by polymerization using a monomer having the partial structure represented by the formula (1). As a method of producing the polyamic acid (P), for example, the following can be enumerated: [1] a method of polymerizing a monomer containing a tetracarboxylic dianhydride (hereinafter, also referred to as "specific acid dianhydride") having the partial structure represented by the formula (1); [2] a method of polymerizing a monomer containing a diamine (hereinafter, also referred to as "specific diamine") having the partial structure represented by the formula (1); [3] a method of polymerizing a monomer containing the specific acid dianhydride and the specific diamine; and the like. Among these, from the aspect that the synthesis of the monomer is relatively easy, the use of the specific diamine is preferred, and the method of the above [2] is more preferred.

[0076] (Tetracarboxylic dianhydride)

[0077] • Specific acid dianhydride

[0078] The specific acid dianhydride is not particularly limited in the structure of the other portion as long as it has the partial structure represented by the formula (1). The specific acid dianhydride preferably has the partial structure represented by the formula (1) in the main chain. As specific examples of the specific acid dianhydride, the following compounds represented by the formulae (5-1) to (5-4), and the like can be enumerated.

[0079] [Chemical 3]

[0080]

[0081] • Other acid dianhydride

[0082] In the case of the method (1) and the method (3), the tetracarboxylic dianhydride used in the synthesis of the polyamic acid (P) can be only the specific acid dianhydride, but can also be used in combination with a tetracarboxylic dianhydride not having the partial structure represented by the formula (1) (hereinafter, also referred to as "other acid dianhydride"). In the method (2), the other acid dianhydride is used as the tetracarboxylic dianhydride at the time of the synthesis of the polyamic acid (P). As the other acid dianhydride, for example, aliphatic tetracarboxylic dianhydride and aromatic tetracarboxylic dianhydride can be exemplified. As the aliphatic tetracarboxylic dianhydride, chain tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride can be exemplified.

[0083] As specific examples thereof, the chain tetracarboxylic dianhydride can exemplify 1,2,3,4-butanetetracarboxylic dianhydride and the like;

[0084] The alicyclic tetracarboxylic dianhydride can exemplify 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;

[0085] The aromatic tetracarboxylic dianhydride can exemplify pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol bis-trimellitate anhydride, 4,4'-carbonylbiphthalic anhydride and the like, and in addition thereto, the tetracarboxylic dianhydride described in Japanese Patent Laid-Open No. 2010-97188 can be used. As the tetracarboxylic dianhydride, one kind alone or two or more kinds in combination can be used.

[0086] In terms of the improvement in the solubility of the polymer and the obtainment of a liquid crystal alignment film exhibiting good electric characteristics, the tetracarboxylic dianhydride used in the synthesis of the polyamic acid is preferably at least one selected from the group consisting of chain tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, and more preferably the alicyclic tetracarboxylic dianhydride. The use amount of the alicyclic tetracarboxylic dianhydride is preferably 20 mol% or more, more preferably 40 mol% or more, and further preferably 50 mol% or more, relative to the total amount of the tetracarboxylic dianhydride used in the synthesis of the polyamic acid.

[0087] (Diamine)

[0088] • Specific diamine

[0089] 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 formula (1). The specific diamine can have the partial structure represented by the formula (1) in the main chain or in the side chain. As the specific diamine, for example, a compound represented by the following formula (6-1) and a compound represented by the following formula (6-2) can be mentioned.

[0090] [Chemical Formula 4]

[0091] H2N-Y 1 -A 1 -Y 2 -NH2 (6-1)

[0092] (In the formula (6-1), A 1 is a divalent group represented by the formula (1). Y 1 and Y 2 are each independently a single bond or a divalent organic group.)

[0093] [Chemical Formula 5]

[0094]

[0095] (In the formula (6-2), A 2 is a divalent group represented by the formula (1). Y 3 is a trivalent aromatic ring group. Y 4 is a single bond or a divalent linking group. Y 5 is a hydrogen atom or a monovalent organic group.)

[0096] In the formula (6-1), as the divalent organic group represented by Y 1 and Y 2 , for example, a divalent hydrocarbon group having a carbon number of 1 to 20; a divalent group in which a part of methylene groups of the hydrocarbon group is substituted with -O-, -CO-, -COO- or -NR 30 -(R 30 is a hydrogen atom or an alkyl group having a carbon number of 1 to 6) can be mentioned, and they can also have a substituent. As the divalent heterocyclic group, for example, a group obtained by removing two hydrogen atoms from a nitrogen-containing heterocyclic ring such as pyridine, piperazine, piperidine and the like can be mentioned. As the substituent which Y 1 and Y 2 can have, for example, a halogen atom, an alkoxy group, a hydroxyl group, a carboxyl group, a cyano group, a nitro group and the like can be mentioned.

[0097] In the formula (6-2), Y 3The trivalent aromatic ring group represented is a group obtained by removing three hydrogen atoms from the ring portion of an aromatic ring. As the aromatic ring, for example, there can be mentioned: an aromatic hydrocarbon ring such as a benzene ring, a naphthalene ring, and an anthracene ring; and an aromatic heterocyclic ring such as a pyridine ring and a pyridazine ring. Of these, a benzene ring and a pyridine ring are particularly preferred. Furthermore, a substituent can also be introduced into the aromatic ring possessed by the aromatic ring group. As the substituent, for example, there can be mentioned: an alkyl group having a carbon number of 1 to 3; a halogen atom; a hydroxyl group; and the like.

[0098] As Y 4 The divalent linking group represented can be mentioned: -0-; -CO-; -COO-; -NR 30 -; -CO-NR 30 -; an alkanediyl group having a carbon number of 1 to 3; and the like.

[0099] As Y 5 The monovalent organic group represented can be mentioned: a monovalent hydrocarbon group having a carbon number of 1 to 20; a monovalent group in which a part of the methylene group possessed by the hydrocarbon group is substituted with -0-, -CO-, -COO-, or -NR 30 -; a monovalent heterocyclic group; and the like, which can also have a substituent.

[0100] As specific examples of the specific diamine, the compound represented by the formula (6-1) can be mentioned, for example, the compounds represented by the following formulas (6-1-1) to (6-1-22), respectively; and the like. The compound represented by the formula (6-2) can be mentioned, for example, the compounds represented by the following formulas (6-2-1) to (6-2-4), respectively; and the like.

[0101] [Chemical Formula 6]

[0102]

[0103] [Chemical Formula 7]

[0104]

[0105] [Chemical Formula 8]

[0106]

[0107] [Chemical Formula 9]

[0108]

[0109] [Chemical Formula 10]

[0110]

[0111] • Other diamines

[0112] In the case of the method [2] and the method [3], the diamine used in the synthesis of the polyamic acid (P) can be only a specific diamine, but can also be used in combination with a diamine not having the partial structure represented by the formula (1) (hereinafter, also referred to as "another diamine"). In the method [1], another diamine is used as the diamine at the time of the synthesis of the polyamic acid (P). As the other diamine, for example, aliphatic diamines, aromatic diamines, diaminosiloxanes, and the like can be exemplified. As the aliphatic diamine, chain diamines and alicyclic diamines can be exemplified.

[0113] As the specific examples of the diamine used in the synthesis of the polyamic acid, chain diamines can be exemplified: m-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, and the like;

[0114] Alicyclic diamines can be exemplified: 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and the like;

[0115] Aromatic diamines can be exemplified: p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4-aminophenyl-4-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,5-bis(4-aminophenoxy)pentane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,6-bis(4-aminophenoxy)hexane, bis[2-(4-aminophenyl)ethyl]adipate, 2,6-diaminopyridine, 1,4-bis-(4-aminophenyl)-piperazine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(phenylenediisopropylidene)dianiline, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-[4,4'-propane-1,3-diylbis(piperidin-1,4-diyl)]dianiline, 4,4'-diaminobenzanilide, 4,4'-diaminostyrylbenzene, 1,4-bis(4-aminophenyl)-piperazine, and the like main-chain type diamines;

[0116] Dodecyloxy-2,4-diaminobenzene, pentadecyloxy-2,4-diaminobenzene, hexadecyloxy-2,4-diaminobenzene, octadecyloxy-2,4-diaminobenzene, pentadecyloxy-2,5-diaminobenzene, octadecyloxy-2,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestanolyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanolyloxy-2,4-diaminobenzene, cholestanyloxy-3,5-diaminobenzoic acid, cholestanolyloxy-3,5-diaminobenzoic acid, cholestanyloxy-3,5-diaminobenzoic acid, 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, 3,5-diaminobenzoic acid = 5ξ-cholestane-3-yl, the following formula (E-1)

[0117] [Chemical 11]

[0118]

[0119] (In formula (E-1), X I and X II independently represent a single bond, -O-, -COO-, or -OCO- (in which, " * " represents a bonding bond with X I ). R I is an alkanediyl group having 1 to 3 carbons. R II is a single bond or an alkanediyl group having 1 to 3 carbons. R III is an alkyl group having 1 to 20 carbons, an alkoxy group, a fluoroalkyl group, or a fluoroalkoxy group. 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. In which, 1 ≤ a + b + c ≤ 3.)

[0120] a side chain type diamine represented by a compound, etc.

[0121] The diaminoorganosiloxane can be exemplified by 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, etc., and in addition thereto, the diamine described in Japanese Patent Laid-Open No. 2010-97188 can be used.

[0122] In addition, as other diamines, -NR- (wherein R is a monovalent hydrocarbon group having 1 to 10 carbon atoms or a thermally dissociable group) or a diamine having a nitrogen-containing heterocyclic structure (hereinafter, also referred to as "nitrogen-containing diamine") can be exemplified. As the nitrogen-containing diamine, in addition to the corresponding compounds among the above exemplified other diamines, for example, 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, 4-(4-aminophenoxy carbonyl)-1-(4-aminophenyl)piperidine, and the like can be exemplified. In the synthesis of the polyamic acid (P), as the specific diamine, one kind alone or two or more kinds in combination can be used.

[0123] In the polyamic acid (P), the content ratio of the partial structure represented by the formula (1) is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 15 mol% or more, with respect to all diamine units possessed by the polyamic acid (P). In addition, the content ratio of the partial structure represented by the formula (1) in the polyamic acid (P) is preferably 95 mol% or less, more preferably 90 mol% or less, and further preferably 85 mol% or less, with respect to all diamine units possessed by the polyamic acid (P). If the content ratio of the partial structure represented by the formula (1) in the polyamic acid (P) is within the range, the polyamic acid (P) is excellent in light reactivity, and an alignment film which shows excellent liquid crystal alignment properties even after long-time irradiation of a backlight can be formed, and is thus preferred in this respect.

[0124] • Synthesis of polyamic acid

[0125] The polyamic acid (P) can be obtained by reacting the tetracarboxylic dianhydride as described above with a diamine, as necessary, and a molecular weight adjusting agent. The use ratio of the tetracarboxylic dianhydride and the diamine for the synthesis reaction of the polyamic acid (P) is preferably 0.2 equivalents to 2 equivalents of the acid anhydride group of the tetracarboxylic dianhydride with respect to 1 equivalent of the amino group of the diamine.

[0126] As the molecular weight adjusting agent, for example, acid monomers such as maleic anhydride, phthalic anhydride, itaconic anhydride, and the like; monoamine compounds such as aniline, cyclohexylamine, n-butylamine, and the like; monoisocyanate compounds such as phenyl isocyanate, naphthyl isocyanate, and the like can be exemplified. The use ratio of the molecular weight adjusting agent is preferably set to 20 parts by mass or less with respect to 100 parts by mass of the total of the tetracarboxylic dianhydride and the diamine used.

[0127] The synthesis reaction of the polyamic acid (P) is preferably performed in an organic solvent. The reaction temperature at this time is preferably -20°C to 150°C, and the reaction time is preferably 0.1 hour to 24 hours. As the organic solvent used in the reaction, for example, aprotic polar solvents, phenol-based solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like can be exemplified. An especially preferred organic solvent is preferably one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethyl urea, hexamethylphosphoric triamide, m-cresol, dimethylphenol, and halogenated phenol, or a mixture of one or more of these and another organic solvent (e.g., butyl cellosolve, diethylene glycol diethyl ether, and the like) is used. The amount of the organic solvent used (a) is preferably set to an amount of 0.1 mass% to 50 mass% relative to the total amount of the reaction solution (a+b) with respect to the total amount of the tetracarboxylic dianhydride and the diamine (b).

[0128] The reaction solution in which the polyamic acid (P) is dissolved is obtained in the above-described manner. The reaction solution can be directly used for the production of the liquid crystal alignment agent, or the polyamic acid (P) contained in the reaction solution can be separated and then used for the production of the liquid crystal alignment agent.

[0129] (Polyamic acid ester)

[0130] The polyamic acid ester (hereinafter, also referred to as "polyamic acid ester (P)") as the polymer (P) can be obtained, for example, by a method in which the polyamic acid (P) obtained by the synthesis reaction is reacted with an esterification agent, a method in which a tetracarboxylic acid diester is reacted with a diamine including a specific diamine, and a method in which a tetracarboxylic acid diester dihalide is reacted with a diamine including a specific diamine. The polyamic acid ester (P) contained in the liquid crystal alignment agent of the present disclosure can have only an amic acid ester structure, or can be a partial ester 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 can be directly used for the production of the liquid crystal alignment agent, or the polyamic acid ester (P) contained in the reaction solution can be separated and then used for the production of the liquid crystal alignment agent.

[0131] (Polyimide)

[0132] The polyimide (hereinafter, also referred to as "polyimide (P)") as the polymer (P) can be obtained, for example, by subjecting the polyamic acid (P) synthesized in the above-described manner to dehydration and ring closure and imidization. The polyimide (P) can be a fully imidized product in which all of the amic acid structures of the polyamic acid (P) as a precursor thereof are subjected to dehydration and ring closure, or can be a partially imidized product in which only a part of the amic acid structures are subjected to dehydration and ring closure, and the amic acid structures and imide ring structures coexist. The imidization rate of the polyimide (P) is preferably 20% or more, and more preferably 30% to 95%. The imidization rate is a proportion expressed in percentage of the number of imide ring structures with respect to the total of the number of amic acid structures and the number of imide ring structures of the polyimide. Here, a part of the imide ring can be an iso-imide ring.

[0133] The dehydration and ring closure of the polyamic acid (P) is preferably performed by a method in which the polyamic acid (P) is dissolved in an organic solvent, a dehydrating agent and a dehydration and ring closure catalyst are added to the solution, and heating is performed as necessary. In the method, as the dehydrating agent, for example, an acid anhydride such as acetic anhydride, propionic anhydride, trifluoroacetic anhydride, or the like can be used. The amount of the dehydrating agent used is preferably 0.01 mol to 20 mol with respect to 1 mol of the amic acid structure of the polyamic acid (P). As the dehydration and ring closure catalyst, for example, a tertiary amine such as pyridine, collidine, lutidine, triethylamine, or the like can be used. The amount of the dehydration and ring closure catalyst used is preferably 0.01 mol to 10 mol with respect to 1 mol of the dehydrating agent used. As the organic solvent used in the dehydration and ring closure reaction, the organic solvents exemplified as the organic solvents used in the synthesis of the polyamic acid (P) can be listed. The reaction temperature of the dehydration and ring closure reaction is preferably 0°C to 180°C. The reaction time is preferably 1.0 hour to 120 hours. Furthermore, the reaction solution containing the polyimide (P) obtained by the reaction can be directly supplied to the production of the liquid crystal alignment agent, or can be supplied to the production of the liquid crystal alignment agent after the polyimide (P) is separated. In addition, the polyimide (P) can be obtained by imidization of the polyamic acid ester (P).

[0134] Regarding the solution viscosity of the polyamic acid, the polyamic acid ester, and the polyimide contained in the liquid crystal alignment agent, when a solution having a concentration of 10% by mass is prepared, the solution viscosity is preferably 10 mPa-s to 800 mPa-s, and more preferably 15 mPa-s to 500 mPa-s. Furthermore, the solution viscosity (mPa-s) is a value measured at 25°C using an E-type rotational viscometer for a polymeric solution having a concentration of 10% by mass prepared using a good solvent for the polymer (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, or the like).

[0135] The weight average molecular weight (Mw) of the polyamide acid, polyamide acid ester and polyimide, measured by gel permeation chromatography (GPC) in terms of polystyrene, is preferably 1,000 to 500,000, more preferably 5,000 to 100,000. The molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the number average molecular weight (Mn) measured by GPC in terms of polystyrene is preferably 15 or less, more preferably 10 or less.

[0136] (polyorganosiloxane)

[0137] The method of 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 formula (1). The polysiloxane (P) can be obtained, for example, by a hydrolysis / condensation reaction of a hydrolyzable silane compound. Specifically, the following methods of [1] and [2] can be exemplified.

[0138] [1] A method of synthesizing an epoxy group-containing polyorganosiloxane by subjecting a hydrolyzable silane compound (ms-1) having an epoxy group, or a mixture of the silane compound (ms-1) and another silane compound to hydrolysis condensation, and then reacting the obtained epoxy group-containing polyorganosiloxane with a carboxylic acid (hereinafter, also referred to as "specific carboxylic acid") having the partial structure represented by the formula (1).

[0139] [2] A method of subjecting a hydrolyzable silane compound (ms-2) having the partial structure represented by the formula (1), or a mixture of the silane compound (ms-2) and another silane compound to hydrolysis condensation.

[0140] Among these, the method of [1] is simple and can improve the introduction rate of the partial structure represented by the formula (1) in the polysiloxane (P), and is thus preferred in terms of this aspect.

[0141] As specific examples of the silane compound (ms-1), for example, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 2-glycidyloxyethyltrimethoxysilane, 2-glycidyloxyethylmethyldimethoxysilane, 2-glycidyloxyethyldimethylmethoxysilane, 2-glycidyloxyethyldimethylethoxysilane, 4-glycidylobutyltrimethoxysilane, 4-glycidylobutylmethyldimethoxysilane, 4-glycidylobutylmethyldiethoxysilane, 4-glycidylobutyldimethylmethoxysilane, 4-glycidylobutyldimethylethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(3,4-epoxycyclohexyl)propyltrimethoxysilane, and the like can be listed. As the silane compound (ms-1), one of these or two or more of these can be used in combination.

[0142] The other silane compound used in the synthesis of the epoxy group-containing polyorganosiloxane is not particularly limited as long as it is a silane compound that exhibits hydrolysis. As specific examples thereof, for example, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, and the like alkoxysilane;

[0143] 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(3-cyclohexylamino)propyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, and the like nitrogen / sulfur atom-containing alkoxysilane; 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 6-(meth)acryloyloxyhexyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, and the like unsaturated hydrocarbon-containing alkoxysilane, and in addition thereto, trimethoxysilylpropylsuccinic anhydride, and the like can be listed. As the other silane compound, one of these or two or more of these can be used in combination. Furthermore, in the present specification, "(meth)acryloyloxy" is inclusive of "acryloyloxy" and "methacryloyloxy".

[0144] The hydrolysis / condensation reaction of the silane compound can be performed by reacting one or more of the silane compounds described above with water, preferably in the presence of a suitable catalyst and an organic solvent. In the reaction, the proportion of water used is preferably 1 mole to 30 moles per 1 mole of the silane compound (total amount). As the catalyst used, for example, an acid, an alkali metal compound, an organic base, a titanium compound, a zirconium compound, or the like can be exemplified. The amount of catalyst used varies depending on the kind of catalyst, the reaction conditions such as the temperature, and the like, and should be appropriately set, for example, preferably 0.01 times the mole to 3 times the mole per the total amount of the silane compound. As the organic solvent used, for example, a hydrocarbon, a ketone, an ester, an ether, an alcohol, or the like can be exemplified. Among these, it is preferable to use an organic solvent that is non-water-soluble or poorly water-soluble. The proportion of the organic solvent used is preferably 10 parts by mass to 10,000 parts by mass per 100 parts by mass of the silane compound used in the reaction.

[0145] The hydrolysis / condensation reaction is preferably performed by heating, for example, using an oil bath or the like. At this time, the heating temperature is preferably set to 130°C or lower, and the heating time is preferably set to 0.5 hours to 12 hours. After the reaction is completed, the organic solvent layer separated from the reaction solution is dried as necessary using a drying agent, and then the solvent is removed, whereby the polysiloxane of interest can be obtained. Furthermore, the method of synthesizing the polysiloxane is not limited to the hydrolysis / condensation reaction, and for example, the reaction of a hydrolyzable silane compound in the presence of oxalic acid and an alcohol, or the like can be performed.

[0146] In the method of [1], the epoxy group-containing polyorganosiloxane obtained by the reaction is further reacted with a specific carboxylic acid. Thus, the epoxy group of the epoxy group-containing polyorganosiloxane reacts with the carboxyl group of the specific carboxylic acid, and a polyorganosiloxane (P) having a partial structure represented by the formula (1) in the side chain can be obtained.

[0147] As specific examples of the specific carboxylic acid, for example, compounds represented by the following formulas (7-1) to (7-5), and the like can be exemplified.

[0148] [Chem. 12]

[0149]

[0150] The proportion of the partial structure represented by the formula (1) in one molecule of the polysiloxane (P) with respect to the silicon atoms possessed by the polysiloxane (P) is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 15 mol% or more. In addition, the proportion of the partial structure represented by the formula (1) in one molecule of the polysiloxane (P) with respect to the silicon atoms possessed by the polysiloxane (P) is preferably 70 mol% or less, more preferably 60 mol% or less, and further preferably 50 mol% or less. If the proportion of the partial structure represented by the formula (1) in the polysiloxane (P) is within the range, it is preferable in terms of the good light reactivity of the polysiloxane (P) and the formation of an alignment film that exhibits good liquid crystal alignment properties even after long-time irradiation of a backlight.

[0151] Further, the carboxylic acid used in the reaction with the epoxy group-containing polyorganosiloxane at the time of synthesis of the polysiloxane (P) can be only the specific carboxylic acid, but other carboxylic acids than the specific carboxylic acid can also be used in combination. The other carboxylic acids can be various carboxylic acids as long as they are carboxylic acids that do not have the partial structure represented by the formula (1). As the other carboxylic acids, for example, carboxylic acids having a mesogenic structure or the like can be exemplified.

[0152] The reaction of the epoxy group-containing polyorganosiloxane with the carboxylic acid is preferably performed in the presence of a catalyst and an organic solvent. As the catalyst used, for example, existing compounds (for example, tertiary organic amines, quaternary organic amines, quaternary ammonium salts, and the like) that promote the reaction of organic bases and epoxy compounds as so-called hardening accelerators can be used. The amount of the catalyst used is preferably 100 parts by mass or less, and more preferably 0.1 parts by mass to 20 parts by mass, with respect to 100 parts by mass of the epoxy group-containing polyorganosiloxane.

[0153] As the organic solvent used in the reaction, for example, hydrocarbons, ethers, esters, ketones, amides, alcohols, and the like can be exemplified. The organic solvent is preferably used at a proportion of 0.1% by mass or more in terms of a solid content concentration (the proportion of the total mass of components other than the solvent in the reaction solution with respect to the total mass of the solution), and more preferably at a proportion of 5% by mass to 50% by mass. In the reaction, the reaction temperature is preferably 0°C to 200°C, and more preferably 50°C to 150°C. The reaction time is preferably 0.1 hours to 50 hours, and more preferably 0.5 hours to 20 hours. After the reaction is completed, the organic solvent layer separated from the reaction liquid is preferably washed with water. After the water washing, the organic solvent layer is dried as necessary with a suitable drying agent, and then the solvent is removed, whereby the polysiloxane (P) as the target product can be obtained.

[0154] The polysiloxane (P) preferably has a solution viscosity of 1 to 500 mPa-s, more preferably 3 to 200 mPa-s, when it is made into a solution at a concentration of 10 mass%. The weight average molecular weight (Mw) of the polysiloxane (P) determined by GPC in terms of polystyrene is preferably 1,000 to 200,000, more preferably 2,000 to 50,000, and further preferably 3,000 to 20,000.

[0155] (addition polymer)

[0156] The addition polymer (P) (hereinafter, also referred to as "addition polymer (P)") as the polymer (P) is not particularly limited in the method of production as long as it has the partial structure represented by the 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 the unsaturated monomer (ma-1) having the partial structure represented by the formula (1), or a mixture of the unsaturated monomer (ma-1) and other unsaturated monomers.

[0157] As the unsaturated monomer, any monomer having a polymerizable carbon-carbon unsaturated bond can be used. As the monomer, for example, compounds having a (meth)acryloyl group, a vinyl group, a vinylphenyl group, a maleimide group, and the like can be exemplified. In terms of the ability to form a liquid crystal alignment film having excellent liquid crystal alignment properties, at least one selected from the group consisting of a poly(meth)acrylate, a maleimide-based polymer, and a styrene-maleimide-based copolymer can be preferably used as the unsaturated polymer (P).

[0158] The unsaturated monomer (ma-1) is not particularly limited as long as it has the partial structure represented by the formula (1). As specific examples of the unsaturated monomer (ma-1), for example, compounds represented by the following formulae (8-1) to (8-10), and the like can be exemplified.

[0159] [Chem. 13]

[0160]

[0161] (In formulae (8-1) to (8-4), R is a hydrogen atom or a methyl group.)

[0162] [Chem. 14]

[0163]

[0164] As specific examples of the other unsaturated monomers, the following can be given: unsaturated carboxylic acids such as (meth)acrylic acid, a-ethylacrylic acid, maleic acid, fumaric acid, and vinylbenzoic acid; unsaturated carboxylic acid esters such as (meth)acrylic acid alkyl esters (e.g., methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and the like), (meth)acrylic acid cycloalkyl esters, 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 (meth)acrylate; unsaturated polycarboxylic anhydrides such as maleic anhydride; and (meth)acrylic compounds;

[0165] aromatic vinyl compounds such as styrene, methylstyrene, divinylbenzene, and 4-(glycidyloxymethyl)styrene; and conjugated diene compounds such as 1,3-butadiene and 2-methyl-1,3-butadiene;

[0166] 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. In the synthesis of the addition polymer (P), one kind of the other unsaturated monomers can be used alone, or two or more kinds thereof can be used in combination.

[0167] The content ratio of the partial structure represented by the formula (1) in one molecule of the addition polymer (P) with respect to all the structural units possessed by the addition polymer (P) is preferably 1 mol% or more, more preferably 2 mol% or more, and further preferably 5 mol% or more. Also, the content ratio of the partial structure represented by the formula (1) in one molecule of the addition polymer (P) with respect to all the structural units possessed by the addition polymer (P) is preferably 60 mol% or less, more preferably 50 mol% or less, and further preferably 40 mol% or less. If the content ratio of the partial structure represented by the formula (1) in the addition polymer (P) is within the range, the photo-reactivity of the addition polymer (P) is good, and an alignment film that exhibits good liquid crystal alignment properties even after long-time irradiation of a backlight can be formed, which is preferable in terms of the above aspects.

[0168] Addition polymers (P) can be obtained, for example, by polymerizing monomers in the presence of a polymerization initiator. Preferred polymerization initiators include, for example, azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile). The proportion of polymerization initiator used is preferably set to 0.01 to 30 parts by mass relative to 100 parts by mass of all monomers used in the reaction.

[0169] 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 set to 30°C to 120°C, and the reaction time is preferably set to 1 hour to 36 hours. The amount (a) of organic solvent used is preferably set to be 0.1% to 60% by mass relative to the total amount (b) of monomers used in the reaction and the total amount (a+b) of the reaction solution.

[0170] For addition polymers (P), the weight-average molecular weight (Mw) of polystyrene as determined by GPC is preferably 250 to 500,000, more preferably 500 to 100,000.

[0171] Furthermore, the method for manufacturing addition polymers (P) is not limited to those described above. For example, it can also be obtained by polymerizing a monomer containing an unsaturated monomer (m-1) having an epoxy group in the presence of a polymerization initiator, and then reacting the polymer of the obtained monomer with a specific carboxylic acid.

[0172] When the polymer (P) has a partial structure represented by formula (1) in its main chain, from the viewpoint of ease of incorporation of the partial structure represented by formula (1), the polymer (P) is preferably at least one selected from the group consisting of polyamic acid, polyimide, and polyamic acid ester. When the polymer (P) has a partial structure represented by 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 polymers.

[0173] <Other Ingredients>

[0174] The liquid crystal alignment agent disclosed herein may further contain components different from polymer (P) (hereinafter also referred to as "other components"). Examples of other components include polymers (hereinafter also referred to as "polymer (Q)") that do not have the partial structure represented by the stated formula (1), crosslinking agents, and solvents.

[0175] (Aggregate (Q))

[0176] The polymer (Q) can be used for the purpose of improving the solubility of the polymer component, or the alignment property and the electrical properties of the liquid crystal alignment film, and the like. As the polymer (Q), for example, a polymer having a main skeleton of a polyamide acid, a polyamide acid ester, a polyimide, a polyorganosiloxane, a polyester, a polyamide, a polybenzoxazole precursor, a polybenzoxazole, a cellulose derivative, a polyacetal, an addition polymer, or the like can be exemplified. In the production of the liquid crystal alignment agent, one kind of the polymer (Q) can be used alone, or two or more kinds of the polymer (Q) can be used in combination.

[0177] In terms of improving the liquid crystal alignment property and the electrical properties of the obtained liquid crystal element, the polymer (Q) is preferably at least one selected from the group consisting of a polyamide acid, a polyamide acid ester, a polyimide, and an addition polymer. As the polyamide acid, the polyamide acid ester, and the polyimide of the polymer (Q), a polymer obtained by reacting the other acid dianhydride with the other diamine can be exemplified. The addition polymer of the polymer (Q) is preferably a polymer obtained using one or two or more kinds of monomers having a (meth)acryloyl group, a vinyl group, a vinylphenyl group, or a maleimide group, and is more preferably at least one selected from the group consisting of a poly(meth)acrylate, a maleimide-based polymer, and a styrene-maleimide-based copolymer.

[0178] In the case where the polymer (Q) is contained in the liquid crystal alignment agent, the content ratio of the polymer (Q) in the liquid crystal alignment agent is preferably set to 20 parts by mass to 99.9% by mass, and more preferably to 30 parts by mass to 99 parts by mass, with respect to 100 parts by mass of the total amount of the polymer (P) and the polymer (Q).

[0179] In the case where the polymer (Q) is contained in the liquid crystal alignment agent, the content ratio of the polymer (P) in the liquid crystal alignment agent is preferably set to 0.5 parts by mass or more, and more preferably to 1% by mass or more, with respect to 100 parts by mass of the polymer (Q). In addition, the content ratio of the polymer (P) is preferably set to 150 parts by mass or less, and more preferably to 120 parts by mass or less, and further preferably to 100 parts by mass or less, with respect to 100 parts by mass of the polymer (Q).

[0180] (Crosslinking agent)

[0181] The liquid crystal alignment agent of the present disclosure can contain a crosslinking agent. By formulating the crosslinking agent in the liquid crystal alignment agent, the improvement effect on the reliability with respect to long-time irradiation of a backlight can be improved, which is preferable in this respect.

[0182] The crosslinking agent is preferably a compound having a functional group that can react with the functional group possessed by the polymer (P) (e.g., an amino group, a carboxyl group, an epoxy group, a polymer unsaturated bond group, etc.). Specifically, a compound 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 trialkoxysilane group, and a polymerizable unsaturated bond group, and having a molecular weight of 1000 or less is preferred. The number of crosslinkable groups possessed by the crosslinking agent is preferably two or more, more preferably three or more, and further preferably 3 to 8.

[0183] In the case of formulating the crosslinking agent, the content ratio of the crosslinking agent in the liquid crystal alignment agent is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more, relative to 100 parts by mass of the total amount of the polymer component in the liquid crystal alignment agent. In addition, from the viewpoint of suppressing a decrease in performance due to the addition of an excess amount, the content ratio of the crosslinking agent is preferably 40 parts by mass or less, and more preferably 30 parts by mass or less, relative to 100 parts by mass of the total amount of the polymer component in the liquid crystal alignment agent. Furthermore, as the crosslinking agent, one kind alone or two or more kinds in combination can be used.

[0184] (Solvent)

[0185] The liquid crystal alignment agent of the present disclosure is preferably prepared as a liquid composition in which the polymer (P) and the components used as necessary are dispersed or dissolved in a suitable solvent. The solvent used is preferably an organic solvent, and examples thereof include 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, ethylene glycol-iso-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, and the like. These can be used alone or in combination of two or more.

[0186] As other components, in addition to the solvent, examples include an antioxidant, a metal chelate compound, a hardening accelerator, a surfactant, a filler, a dispersant, a photosensitizer, and the like. The formulation ratio of these can be appropriately selected depending on the respective compounds within a range that does not impair the effects of the present disclosure.

[0187] The solid content concentration in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent in the liquid crystal alignment agent in the total mass of the liquid crystal alignment agent) can be appropriately selected in consideration of viscosity, volatility, and the like, and is preferably in the range of 1 to 10% by mass. That is, the liquid crystal alignment agent is applied to the surface of a substrate as described later, preferably with heating, thereby forming a coating film that is a liquid crystal alignment film or becomes a liquid crystal alignment film. At this time, if the solid content concentration is 1% by mass or more, the film thickness of the coating film can be sufficiently ensured, and a good liquid crystal alignment film can be easily obtained, which is preferable from this viewpoint. In addition, if the solid content concentration is 10% by mass or less, the film thickness of the coating film does not become excessively large, a good liquid crystal alignment film can be obtained, and the viscosity of the liquid crystal alignment agent can be appropriately ensured, and the applicability can be made good.

[0188] From the viewpoint of sufficiently obtaining the effects of the present disclosure, the proportion of the polymeric component in the liquid crystal alignment agent is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 50 parts by mass or more, with respect to 100 parts by mass of the total of the solid components (i.e., components other than the solvent) in the liquid crystal alignment agent.

[0189] Liquid crystal alignment film and liquid crystal element

[0190] The liquid crystal alignment film of the present disclosure can be formed from the liquid crystal alignment agent produced in the above-described manner. In addition, the liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described in the above. The operation mode of the liquid crystal in the liquid crystal element is not particularly limited, and can be applied, for example, to various modes such as a Twisted Nematic (TN) mode, a Super Twisted Nematic (STN) mode, a Vertical Alignment (VA) mode (including a Vertical Alignment-Multi-domain Vertical Alignment (VA-MVA) mode, a Vertical Alignment-Patterned Vertical Alignment (VA-PVA) mode, and the like), an In-Plane Switching (IPS) mode, a Fringe Field Switching (FFS) mode, an Optically Compensated Bend (OCB) mode, and the like. The liquid crystal element can be manufactured, for example, by a method including the following Process 1 to Process 3. In Process 1, the substrate is used differently depending on the desired operation mode. Process 2 and Process 3 are common to each operation mode.

[0191] (Process 1: formation of a coating film)

[0192] First, a liquid crystal alignment agent is applied to a substrate, and preferably the coated surface is heated, thereby forming a coating film on the substrate. As the substrate, for example, a float glass, a soda glass, or the like; a transparent substrate including polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly(alicyclic olefin), or the like can be used. As a transparent conductive film provided on one surface of the substrate, a NESA (NESA is a registered trademark of PPG Industries, Inc.) film including tin oxide (Sn02), an indium tin oxide (ITO) film including indium oxide-tin oxide (In203-Sn02), or the like can be used. In the case of manufacturing a liquid crystal element of a TN type, a STN type, or a VA type, two pieces of substrates provided with a patterned transparent conductive film are used. On the other hand, in the case of manufacturing a liquid crystal element of an IPS type or an FFS type, a substrate provided with an electrode including a transparent conductive film or a metal film patterned in a comb shape, and an opposing substrate not provided with an electrode are used. As the metal film, for example, a film including a metal such as chromium can be used. The application of the liquid crystal alignment agent to the substrate is preferably performed on the electrode formation surface using a flexographic printing method, a spin coating method, a roll coater method, or an inkjet printing method.

[0193] After the application of the liquid crystal alignment agent, preheating (pre-baking) is preferably performed for the purpose of preventing sagging of the applied liquid crystal alignment agent or the like. The pre-baking temperature is preferably 30°C to 150°C, more preferably 40°C to 120°C. The pre-baking time is preferably 0.25 minutes to 10 minutes.

[0194] Subsequently, a calcination (post-baking) process is performed for the purpose of further removing a solvent and, as necessary, thermally imidizing an amide acid structure present in a polymer. From the viewpoint of suppressing deterioration such as discoloration caused by high temperature when a liquid crystal alignment film is formed on a color filter, and the viewpoint of reducing environmental load, the calcination temperature (post-baking temperature) at this time is preferably 250°C or lower, more preferably 230°C or lower, and further preferably 180°C or lower. In addition, from the viewpoint of suppressing a decrease in liquid crystal alignment properties or reliability due to the influence of a solvent component remaining in the film, the post-baking temperature is preferably 80°C or higher, and more preferably 120°C or higher. The post-baking time is preferably 5 minutes to 150 minutes. The film thickness of the film thus formed is preferably 0.001 μm to 1 μm. After the liquid crystal alignment agent is applied to the substrate, the organic solvent is removed, thereby forming a liquid crystal alignment film or a coating film that becomes a liquid crystal alignment film.

[0195] (Step 2: Alignment treatment)

[0196] In the case of manufacturing a liquid crystal element of TN type, STN type, IPS type, or FFS type, a treatment for imparting a liquid crystal aligning ability to the coating film formed in the above-mentioned Step 1 (alignment treatment) is performed. By this, the aligning ability of the liquid crystal molecules is imparted to the coating film to become a liquid crystal alignment film. As the alignment treatment, rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton or the like, or photo-alignment treatment in which the coating film is subjected to light irradiation to impart the liquid crystal aligning ability is preferable. In the case of manufacturing a liquid crystal element of vertical alignment type, the coating film formed in the above-mentioned Step 1 can be directly used as a liquid crystal alignment film, and in order to further improve the liquid crystal aligning ability, the alignment treatment can also be performed on the coating film.

[0197] The light irradiation in the photo-alignment treatment can be performed by a method in which the coating film after the post-baking step is irradiated, a method in which the coating film after the pre-baking step and before the post-baking step is irradiated, or a method in which the coating film is irradiated during the heating of the coating film in at least either one of the pre-baking step and the post-baking step. In the photo-alignment treatment, as the radiation to be irradiated to the coating film, for example, ultraviolet rays and visible rays including light having a wavelength of 150 nm to 800 nm can be used. Ultraviolet rays including light having a wavelength of 200 nm to 400 nm are preferable. In the case where the radiation is polarized, it can be linearly polarized, or it can be partially polarized. In the case where the radiation to be used is linearly polarized or partially polarized, the irradiation can be performed from a direction perpendicular to the surface of the substrate, it can be performed from an oblique direction, or it can be performed in combination of these. In the case where the radiation is not polarized, the irradiation direction is set to an oblique direction.

[0198] As the light source to be used, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used. The irradiation amount of the radiation is preferably 400 J / m 2 to 20,000 J / m 2 , more preferably 1,000 J / m 2 to 5,000 J / m 2 In order to improve the reactivity, the light irradiation to the coating film can be performed while the coating film is warmed. Further, a step in which the organic film after the light irradiation treatment is brought into contact with water, a water-soluble organic solvent, or a mixed solvent of water and a water-soluble organic solvent can be further included.

[0199] (Step 3: Construction of Liquid Crystal Cell)

[0200] Two substrates each of which has a liquid crystal alignment film formed thereon in the above manner are prepared, and liquid crystal is disposed between the two substrates disposed facing each other, whereby a liquid crystal cell is manufactured. In manufacturing the liquid crystal cell, for example, the following methods can be mentioned: (1) a method in which two substrates are disposed facing each other with a gap (spacer) therebetween, and the periphery of the two substrates is bonded using a sealant, liquid crystal is injected and filled into a cell gap defined by the surfaces of the substrates and the sealant, and then the injection hole is sealed; (2) a method (one drop filling (ODF) method) in which a sealant is applied to a prescribed portion on one of the substrates on which a liquid crystal alignment film is formed, liquid crystal is further dropped at prescribed positions on the liquid crystal alignment film surface, and then the other substrate is bonded facing the liquid crystal alignment film, and the liquid crystal is allowed to spread over the entire surface of the substrate. It is preferable that, for the manufactured liquid crystal cell, further treatment is performed, that is, heating to a temperature at which the used liquid crystal attains an isotropic phase, and then slow cooling to room temperature, whereby the flow alignment at the time of filling of the liquid crystal is removed.

[0201] As the sealant, for example, a hardening agent and an epoxy resin containing alumina balls as spacers can be used. As the spacers, a photo spacer, a bead spacer, or the like can be used.

[0202] As the liquid crystal used, a nematic liquid crystal, a smectic liquid crystal, and the like can be mentioned, of which a nematic liquid crystal is preferable. As the nematic liquid crystal, for example, a Schiff base-based liquid crystal, an azoxy-based liquid crystal, a biphenyl-based liquid crystal, a phenylcyclohexane-based liquid crystal, an ester-based liquid crystal, a terphenyl-based liquid crystal, a biphenylcyclohexane-based liquid crystal, a pyrimidine-based liquid crystal, a dioxane-based liquid crystal, a bicyclooctane-based liquid crystal, a cubane-based liquid crystal, and the like can be used. In addition, for example, a cholesteric liquid crystal, a chiral agent, a ferroelectric liquid crystal, and the like can be added to these liquid crystals and used.

[0203] Subsequently, a polarizing plate is bonded to the outer surface of the liquid crystal cell as necessary. As the polarizing plate, a polarizing plate in which a polarizing film called an "H film" in which polyvinyl alcohol is extended and oriented and iodine is absorbed is sandwiched by a cellulose acetate protective film, or a polarizing plate including the H film itself can be mentioned. Thus, a liquid crystal element is obtained.

[0204] The liquid crystal element disclosed herein can be effectively applied to a variety of uses. Specifically, it can be used in various display devices such as clocks, portable game consoles, word processors, notebook computers, car navigation systems, camcorders, personal digital assistants (PDAs), digital cameras, mobile phones, smartphones, various monitors, LCD TVs, information displays, or dimming films. Furthermore, the liquid crystal element formed using the liquid crystal alignment agent disclosed herein can also be used in optical films such as retardation films.

[0205] Liquid Crystal Display Devices

[0206] One embodiment of the liquid crystal display device of the present invention includes a photoalignment film formed using the liquid crystal alignment agent described above as the liquid crystal alignment film. Hereinafter, the liquid crystal display device of the present invention will be described with reference to the accompanying drawings.

[0207] like Figure 1 As shown, the liquid crystal display device 10 includes: a pair of substrates, including 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. Furthermore, the present invention can also be applied to other driving methods (e.g., passive matrix method, plasma address method, etc.).

[0208] The first substrate 11 is a TFT substrate in which pixel electrodes 15 containing a transparent conductor such as indium tin oxide (ITO), TFTs as switching elements, scan lines, or signal lines are disposed on the surface of a transparent substrate 14 containing glass or resin on the side of the liquid crystal layer 13. The second substrate 12 is a color filter (CF) substrate in which a black matrix 17, a color filter 18, and opposing electrodes 19 (also called common electrodes) containing a transparent conductor are disposed on the surface of a transparent substrate 16 containing glass or resin on the side of the liquid crystal layer 13.

[0209] A liquid crystal alignment film is formed on a pair of substrates 11 and 12, which aligns liquid crystal molecules in a predetermined orientation relative to the film surface. The liquid crystal alignment film is a vertical alignment film. The liquid crystal display device 10 includes 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 as liquid crystal alignment films.

[0210] The first substrate 11 and the second substrate 12 are arranged so that the electrode arrangement surface of the first substrate 11 and the electrode arrangement surface of the second substrate 12 face each other, with the spacer 24 interposed and a prescribed gap (cell gap) provided. Further, in Figure 1 the present embodiment, a columnar spacer is shown as the spacer 24, but other spacers such as a bead spacer can also be used. The pair of substrates 11, 12 arranged facing each other are bonded at the peripheral portions thereof via the sealing material 25. The space surrounded by the first substrate 11, the second substrate 12, and the sealing material 25 is filled with a liquid crystal composition. Thus, the liquid crystal layer 13 is formed between the first substrate 11 and the second substrate 12. The liquid crystal layer 13 is filled with a liquid crystal having a negative dielectric anisotropy.

[0211] A polarizing plate (not shown) is arranged on the outer side of each of the first substrate 11 and the second substrate 12. A terminal region is provided at the outer edge portion of the first substrate 11. The liquid crystal display device 10 is driven by connecting a driver integrated circuit (IC) or the like for driving the liquid crystal in the terminal region.

[0212] At least one of the first alignment film 22 and the second alignment film 23 is a photoalignment film, and in the present embodiment, at least the first alignment film 22 is a photoalignment film. Further, in the present specification, the "photoalignment 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 photoalignment group with polarized or non-polarized light. The "photoalignment group" is a functional group that imparts anisotropy to a film through a photoisomerization reaction, photodimerization reaction, photodecomposition reaction, or photorearrangement reaction caused by light irradiation.

[0213] The first alignment film 22 is dividedly exposed by photoalignment treatment so that the alignment direction of the liquid crystal molecules differs for each region. The first alignment film 22 is formed by repeatedly irradiating a coating film formed using a liquid crystal alignment agent containing a polymer (P) having a partial structure represented by the formula (1) with polarized radiation at an angle using a photomask (e.g., a polarizer). On the other hand, the second alignment film 23 is not dividedly exposed. With respect to the second alignment film 23, in the present embodiment, a coating film formed from the same liquid crystal alignment agent as the first alignment film 22 is used directly without irradiation with light. Thus, the pretilt angle defined by the first alignment film 22 is made different from the pretilt angle defined by the second alignment film 23. Specifically, the pretilt angle defined by the first alignment film 22 is set to be less than 90 degrees, and the pretilt angle defined by the second alignment film 23 is set to be substantially 90 degrees.

[0214] Alternatively, instead of using a structure where the pretilt angle defined by the second alignment film 23 is substantially 90 degrees by not irradiating the organic film formed by the liquid crystal alignment agent during the formation of the second alignment film 23, the entire surface of the organic film formed by the liquid crystal alignment agent can 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 of the second substrate 12 can be either parallel light or diffused light. The term "pretilt angle" refers to 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.

[0215] The liquid crystal display device 10 has a plurality of pixels 30 arranged in a matrix in the display area of ​​the liquid crystal display device 10. Each pixel 30 is oriented and divided into multiple regions with different orientations of liquid crystal molecules. This compensates for the viewing angle characteristics of the liquid crystal display device 10.

[0216] Furthermore, in this specification, the term "pixel" refers to the smallest unit representing the shades (grayscale) of each color in a display. For example, in a color filter-based display device, it is equivalent to the unit representing the individual grayscale levels of red (R), green (G), and blue (B). Therefore, when referred to as "pixel," it refers to each individual R pixel, G pixel, and B pixel, rather than a combination of R pixels, G pixels, and B pixels (image points). That is, in the case of a color liquid crystal display device, one pixel corresponds to any color of the color filter.

[0217] Figure 2 (a)~ Figure 2 Example of the orientation pattern of pixel 30 is shown in (c). Furthermore, in Figure 2 In (a), the cone represents the liquid crystal molecule 35, the vertex side of the cone represents the first substrate 11 side, and the bottom side of the cone represents the second substrate 12 side. Figure 2 (a) is a diagram obtained by viewing the liquid crystal display device 10 from the side of the second substrate 12.

[0218] As an example, such as Figure 2 As shown in (a), four orientation regions with different orientations of liquid crystal molecules 35 are formed in each pixel 30. These four orientation regions (first region 31, second region 32, third region 33, and fourth region 34) are located along the long side of pixel 30 within a pixel. Figure 2 (a)~ Figure 2arrangement configuration. Among the alignment directions of the liquid crystal molecules 35 in the first to fourth domains 31 to 34, the difference between any two alignment directions is substantially equal to an integral multiple of 90 degrees. In addition, in the present specification, the "alignment direction of a liquid crystal molecule" refers to the alignment direction of a liquid crystal molecule in the vicinity of the center in the layer plane and the thickness direction of the liquid crystal layer 13 when a voltage is applied to the liquid crystal display device 10, unless otherwise specified.

[0219] Specifically, when the short side direction of the pixel 30 (the Y direction of (c)) is set to 0 degrees, the alignment direction of the liquid crystal molecules 35 becomes 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. Figure 2 Figure 2 Figure 2 The four domains 31 to 34 are arranged in the order of the fourth domain 34, the second domain 32, the third domain 33, and the first domain 31 along the long side direction of the pixel 30 within one pixel as illustrated in (a) of FIG. 4. At a position at which the light-transmitting region (hereinafter also referred to as "pixel region") of each pixel 30 is divided into two along the long side direction of the pixel 30, the signal line 36 is arranged. Among two domains (the fourth domain 34 and the second domain 32) that form one of the pixel regions divided by the signal line 36, and two domains (the third domain 33 and the first domain 31) that form the other pixel region, the alignment direction of the liquid crystal molecules 35 in each domain is different from each other by 180 degrees (see (a) of FIG. 4). Figure 2

[0220] In addition, in the present specification, the "substantially 45 degrees", "substantially 135 degrees", "substantially 225 degrees", and "substantially 315 degrees" each refer to a range 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).

[0221] Figure 2 (b) of FIG. 4 and (c) of FIG. 4 are diagrams that schematically represent the direction (tilt direction) in which the long axis of the liquid crystal molecules on the surface of the alignment film in each substrate of one pixel 30 is projected onto the substrate in the voltage-off state. Figure 2 Figure 2 Figure 2 In (b) of FIG. 4 and (c) of FIG. 4, Figure 2 (b) of FIG. 4 represents the first substrate 11, Figure 2 (c) of FIG. 4 represents the second substrate 12. Figure 2 Figure 2 ​​​​​​Arrow 37 in (c) indicates the tilt orientation. In the liquid crystal display device 10, by irradiating the first alignment film 22 of the first alignment film 22 and the second alignment film 23 with polarized ultraviolet light in a direction corresponding to the orientation of the liquid crystal molecules 35, the desired pretilt angle characteristics are imparted to each region 31 to 34. On the other hand, the second alignment film 23 is not irradiated with polarized ultraviolet light. Through this exposure process, in each alignment region of the first region 31 to the fourth region 34, the pretilt angle θ1 defined by the first alignment film 22 is set to be less than 90 degrees, and the pretilt angle θ2 defined by the second alignment film 23 is set to be substantially 90 degrees.

[0222] The pretilt angle θ1 only needs to be smaller than the pretilt angle θ2 specified 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, more preferably 88.5 degrees or less. In addition, from the viewpoint of suppressing the decrease in the contrast of the liquid crystal display device 10, the pretilt angle θ1 is preferably 81.0 degrees or more, more preferably 83.0 degrees or more. Furthermore, in this specification, the term "substantially 90 degrees" refers to a range of 90 degrees ± 0.5 degrees.

[0223] like Figure 3 As shown in (b), the tilt orientation of the first substrate 11 side is different in each of the first domain 31 to the fourth domain 34, and the difference between the tilt orientations in any two domains is approximately an integer multiple of 90 degrees. Specifically, regarding the tilt orientation in each domain, when the short side direction (X direction) of the pixel 30 is set to 0 degrees, it 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.

[0224] In addition, such as Figure 3 of (a), Figure 3 As shown in (b), the plurality of pixels 30 of the liquid crystal display device 10 are arranged in such a way that the orientation of adjacent fields in the short side direction (X direction) of the pixel 30 is the same. Furthermore, in Figure 3 of (a), Figure 1 In (b), arrow 41 indicates the exposure orientation of the polarized radiation on the coating formed using a liquid crystal alignment agent. Symbol 44 indicates the region corresponding to the fourth domain 34 of each pixel.

[0225] By using a polymer (P) having a partial structure represented by the formula (1) to form the light alignment film in the liquid crystal display device 10, a liquid crystal display device with high transmittance and high reliability that does not easily degrade liquid crystal alignment even after long-term backlight irradiation can be obtained.

[0226] The liquid crystal display device 10 can be effectively applied to various uses. The liquid crystal display device 10 can be used, for example, as various display devices such as a watch, a portable game machine, a word processor, a notebook personal computer, a car navigation system, a camcorder, a personal digital assistant, a digital camera, a mobile phone, a smartphone, various monitors, a liquid crystal television, an information display, and the like.

[0227] [Examples]

[0228] Hereinafter, the present application will be more specifically described by examples, but the present application is not limited by these examples.

[0229] In the following examples and comparative examples, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer, the imidization rate of the polyimide, and the epoxy equivalent were measured by the following methods.

[0230] [Weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer]

[0231] Mw and Mn are polystyrene conversion values measured by gel permeation chromatography under the following conditions.

[0232] Column: TSKgel GRCXLII manufactured by Tosoh (Co.)

[0233] Solvent: Tetrahydrofuran (in the case of polyorganosiloxane and addition polymer), or lithium bromide and N,N-dimethylformamide solution containing phosphoric acid (in the case of polyamide acid ester)

[0234] Temperature: 40°C

[0235] Pressure: 68 kgf / cm 2

[0236] [Imidization rate]

[0237] A solution containing polyimide was poured into pure water, and the obtained precipitate was sufficiently dried under reduced pressure at room temperature, and then dissolved in deuterated dimethyl sulfoxide, and H-nuclear magnetic resonance (H-NMR) was measured at room temperature with tetramethylsilane as a reference substance. 1 H-nuclear magnetic resonance, 1 (H-NMR). From the obtained H-NMR spectrum, the imidization rate was calculated using the following equation (E-1). 1 (E-1)

[0238] Imidization rate (%) = (1 - A 1 / A 2 x a) x 100 (E-1)

[0239] (In equation (E-1), A1 A is the peak area of the proton derived from the NH group appearing near a chemical shift of 10 ppm 2 A is the peak area of the proton derived from the NH group appearing near a chemical shift of 10 ppm

[0240] [Epoxy equivalent]

[0241] The epoxy equivalent was determined by the hydrochloric acid-methyl ethyl ketone method described in Japanese Industrial Standards (JIS) C 2105.

[0242] The structural formula of the compound used in the present embodiment is shown below. Furthermore, the "compound represented by formula (X)" is simply referred to as "compound (X)" below for convenience.

[0243] (Tetracarboxylic acid derivative)

[0244] [Chemical 15]

[0245]

[0246] (Diamine)

[0247] [Chemical 16]

[0248]

[0249] (Modified carboxylic acid)

[0250] [Chemical 17]

[0251]

[0252] (Unsaturated monomer)

[0253] [Chemical 18]

[0254]

[0255] [Chemical 19]

[0256]

[0257] (Additive)

[0258] [Chemical 20]

[0259]

[0260] [Chemical 21]

[0261]

[0262] 1. Synthesis of compounds

[0263] [Synthesis Example 1-1]

[0264] Compound (DA-1) was synthesized according to the following scheme.

[0265] [Formula 22]

[0266]

[0267] • Synthesis of compound (DA-1-1)

[0268] Compound (DA-1-1) 2.61 g (10.0 mmol) and 4-nitroaniline 1.38 g (10.0 mmol) were dissolved in dichloromethane 50 ml and cooled to 0°C. Then, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide 1.86 g (12.0 mmol) and 4-dimethylaminopyridine 0.61 g (4.99 mmol) were added and allowed to react overnight while returning to room temperature. Then, one separation was performed using hydrochloric acid 50 ml of 1 normal concentration, three separations were performed using water 50 ml, and the organic layer was subjected to solvent distillation using a rotary evaporator, thereby obtaining 3.27 g of compound (DA-1-2).

[0269] • Synthesis of compound (DA-1-1)

[0270] Compound (DA-1-1) 2.61 g (10.0 mmol) and 4-nitroaniline 1.38 g (10.0 mmol) were dissolved in dichloromethane 50 ml and cooled to 0°C. Then, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide 1.86 g (12.0 mmol) and 4-dimethylaminopyridine 0.61 g (4.99 mmol) were added and allowed to react overnight while returning to room temperature. Then, one separation was performed using hydrochloric acid 50 ml of 1 normal concentration, three separations were performed using water 50 ml, and the organic layer was subjected to solvent distillation using a rotary evaporator, thereby obtaining 3.27 g of compound (DA-1-2).

[0271] • Synthesis of compound (DA-1-1)

[0272] To compound (DA-1-2) 3.52 g (10.0 mmol), THF and water 30 ml each were added, and 10 equivalents of tin chloride were added thereto, and the reaction was carried out at 60°C for 2 hours. After the reaction, ethyl acetate 50 ml was added to separate the layers. Further, water 50 ml was added to separate the layers twice, and the organic layer was subjected to solvent distillation using a rotary evaporator. The obtained solid was dissolved in THF 50 ml, and ethanol 30 ml and water 10 ml were added thereto. The good solvent was slowly distilled off using a rotary evaporator, and the precipitated solid was filtered and dried, thereby obtaining compound (DA-1) 2.48 g.

[0273] [Synthesis Example 1-2]

[0274] Compound (DA-3) was synthesized according to the following scheme.

[0275] [Synthesis Example 1-2]

[0276]

[0277] • Synthesis of compound (DA-3-1)

[0278] A solution of triethyl phosphonoacetate 30.2 g (120 mmol) in anhydrous THF 200 ml was added dropwise to sodium hydride 4.8 g (120 mmol), and stirred at 0°C for 2 hours. A solution of 4'-nitro-2,2,2-trifluoroacetophenone 21.9 g (100 mmol) in THF 100 ml was added dropwise thereto, and stirred at room temperature for 1 hour, and then the reaction was carried out with reflux for 2 hours. After the reaction, ethyl acetate 300 ml was added, and separated with saturated NH4Cl solution twice, and with water three times. After the organic layer was subjected to solvent distillation using a rotary evaporator, it was stirred with water 300 ml and sodium hydroxide 10 g at reflux for 3 hours. After the stirring, the pH was made 4 using hydrochloric acid, and the precipitated solid was filtered, washed with water, and dried, thereby obtaining 17.7 g of compound (DA-3-1) as an intermediate. Thereafter, compound (DA-3) was synthesized by the same method as that of compound (DA-1-2), compound (DA-1).

[0279] [Synthesis Example 1-3]

[0280] Compound (DA-4) was synthesized according to the following scheme.

[0281] [Synthesis Example 1-3]

[0282]

[0283] • Synthesis of compound (DA-4-2)

[0284] To compound (DA-4-1) 2.51 g (10.0 mmol) and ammonium acetate 3.85 g (50.0 mmol), aniline 4.65 g (50.0 mmol) were added ethanol 100 ml, and reacted under reflux for 3 hours. After the reaction, solvent distillation was performed using a rotary evaporator, and dissolved in ethyl acetate 50 ml and THF 50 ml, and subjected to three times of separation using 1 equivalent concentration of hydrochloric acid, and three times of separation using water. After solvent distillation was performed on the organic layer, stirring was performed under reflux for 3 hours with water 100 ml and sodium hydroxide 3 g. After the stirring, pH = 4 was made using hydrochloric acid, the precipitated solid was filtered, washed with water, and dried, thereby obtaining 2.76 g of compound (DA-4-2) as an intermediate.

[0285] After that, compound (DA-4) was synthesized by the same method as compound (DA-1-2), compound (DA-1).

[0286] [Synthesis Example 1-4]

[0287] Compound (M-1) was synthesized according to the following scheme.

[0288] [Compound 25]

[0289]

[0290] Synthesis of compound (M-1-2)

[0291] Compound (M-1-1) 31.0 g (100 mmol), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) 76.0 g (500 mmol), Pd(PPh3)2Cl2 87.8 mg (2.50 mmol), 1,4-bis(diphenylphosphino)butane 2.130 g (10.0 mmol) were dissolved in dimethyl sulfoxide (DMSO) 200 ml under nitrogen atmosphere. Then, propargyl acid 7.01 g (100 mmol) was added, and reacted at 50°C for 5 hours. Then, the reaction solution was poured into ethyl acetate 200 ml, subjected to two times of separation using saturated sodium bicarbonate solution 200 ml, two times of separation using 1 equivalent concentration of hydrochloric acid 200 ml, and three times of separation using water 200 ml. Solvent distillation was performed on the organic layer under reduced pressure, thereby obtaining compound (M-1-2) 21.7 g.

[0292] Synthesis of compound (M-1-3)

[0293] Compound (M-1-2) 3.00 g (10.1 mmol) was dissolved in dichloromethane 100 ml, and cooled to 0°C in an ice bath. Then, 47.0-49.0% concentration of hydrobromic acid 9 g was added, and the reaction was performed for 5 hours. The reaction solution was slowly poured into saturated aqueous sodium hydroxide solution, and partitioned. Further, 1 equivalent concentration of hydrochloric acid 50 ml was used for partitioning twice, water 100 ml was used for partitioning twice, and the organic layer was subjected to solvent distillation under reduced pressure. The obtained solid was purified by column chromatography, thereby obtaining 1.68 g of compound (M-1-3).

[0294] • Synthesis of compound (M-1)

[0295] To compound (M-1-3) 1.13 g (3.00 mmol), thionyl chloride 10 ml and a catalytic amount of dimethyl formamide (DMF) were added, and the reaction was performed at 60°C for 2 hours. After the reaction, thionyl chloride was distilled and removed under reduced pressure. The obtained solid was dissolved in anhydrous THF 20 ml to prepare solution A. Separately from solution A, 2-hydroxyethyl methacrylate 0.391 g (3.00 mmol) and triethylamine 0.500 g were dissolved in anhydrous THF 10 ml, and cooled to 0°C in an ice bath. Solution A was added dropwise thereto, and the reaction was performed at room temperature for one night. After the reaction, the reaction solution was subjected to partitioning twice with 1 equivalent concentration of hydrochloric acid, partitioning three times with water, and the organic layer was distilled and removed under reduced pressure. The obtained sticky substance was purified by column chromatography, thereby obtaining compound (M-1) 1.03 g.

[0296] [Synthesis Example 1-5]

[0297] Compound (M-2) was synthesized according to the following scheme.

[0298] [Compound 26]

[0299]

[0300] • Synthesis of compound (M-2-2)

[0301] Compound (M-2-2) was synthesized by the same method as compound (DA-3-1), except that the starting material was changed.

[0302] • Synthesis of compound (M-2)

[0303] To compound (M-2-2) 3.70 g (10.0 mmol) was added thionyl chloride 20 ml with a catalytic amount of DMF, and the reaction was carried out at 60°C for 2 hours. After the reaction, the thionyl chloride was distilled off under reduced pressure. The obtained solid was dissolved in dehydrated THF 50 ml to prepare solution A. On the other hand, 4-hydroxyphenylmaleimide 1.90 g (10.0 mmol) and triethylamine 1.20 g were dissolved in dehydrated THF 50 ml, and the solution was cooled to 0°C with an ice bath. To this was added solution A dropwise, and the reaction was carried out at room temperature overnight. After the reaction, the reaction solution was subjected to two liquid separations with 1 normal hydrochloric acid, three liquid separations with water, and the organic layer was distilled off under reduced pressure. Further, the obtained solid was dissolved in THF 50 ml, and to this were added ethanol 30 ml and water 10 ml. The good solvent was distilled off slowly using a rotary evaporator, and the precipitated solid was filtered and dried, thereby obtaining compound (M-2) 3.31 g.

[0304] [Synthesis Example 1-6]

[0305] Compound (M-3) was synthesized according to the following scheme.

[0306] [Compound 27]

[0307]

[0308] • Synthesis of compound (M-3-2)

[0309] After synthesizing the methyl ester of compound (M-3-2) by the same method as Journal of the American Chemical Society (J. Am. Chem. Soc.) 2001, 123, 40, 9918-9919, hydrolysis was carried out by the same method as compound (DA-1-1), thereby obtaining compound (M-3-2). Thereafter, synthesis was carried out by the same method as compound (M-2).

[0310] [Synthesis Example 1-7 and Synthesis Example 1-8]

[0311] Compound (M-4) and compound (M-5) were synthesized by the same method as compound (M-2) except that the starting material was replaced.

[0312] [Compound 28]

[0313]

[0314] [Compound 29]

[0315]

[0316] [Synthesis Example 1-9]

[0317] Compound (M-6) was synthesized according to the following scheme.

[0318] [Chemical 30]

[0319]

[0320] • Synthesis of compound (M-6-1)

[0321] To compound (M-1-1) 15.46 g (50.0 mmol), methyl methacrylate 16.0 ml (150.0 mmol), phosphorus (o-tolyl) 3 (P(o-tolyl) 3) 1.52 g (5.00 mmol), iPr 2 NEt 26.1 ml (150 mmol), palladium acetate 561 mg (2.50 mmol), DMF 250 ml, nitrogen was sufficiently replaced, warmed to 100°C and reacted for 6 hours. After confirming the disappearance of the raw material by liquid chromatography (LC), it was cooled to room temperature. After cooling, ethyl acetate 200 ml was added, stirred for a moment at room temperature, and the precipitate was filtered and removed. Hexane 200 ml was added to the filtrate, washed twice with 1N HCl 100 ml, twice with distilled water 100 ml, and once with saturated brine 100 ml. The organic layer was dried with anhydrous sodium sulfate, and the solvent was removed by distillation under reduced pressure using a rotary evaporator and an oil pump. The obtained solid was stirred with water 300 ml and sodium hydroxide 5 g under reflux for 3 hours. After stirring, it was made pH = 4 with hydrochloric acid, the precipitated solid was filtered, washed with water, and dried, thereby obtaining 17.2 g of compound (DA-6-2) as an intermediate. After that, compound (M-6) was synthesized by the same method as compound (M-2).

[0322] [Synthesis Example 1-10]

[0323] Compound (M-7) was synthesized by the same method as compound (M-6) except that the raw material was replaced.

[0324] [Chemical 31]

[0325]

[0326] 2. Synthesis of polymer

[0327] <Synthesis of polyamide acid>

[0328] [Synthesis Example 2-1]

[0329] A solution containing 10 mass% of the polymer (P-1) was obtained by dissolving 50 mol parts of 2,3,5-tricarboxy cyclopentyl acetic dianhydride (compound (T-1)), 50 mol parts of 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 70 mol parts of the compound (DA-1), and 30 mol parts of the compound (DA-2) in N-methyl-2-pyrrolidone (NMP) and allowing the mixture to react at 40°C for 3 hours.

[0330] [Synthesis Example 2-4, Synthesis Example 2-11, Synthesis Example 2-12, and Synthesis Example 2-13, Comparative Synthesis Example 3, Comparative Synthesis Example 4]

[0331] The same operation as in the Synthesis Example 2-1 was performed except that the kinds and amounts of the tetracarboxylic acid derivative and diamine used were changed as described in Table 1 below, whereby solutions containing the polymers (P-10), (PAA-S), (PAA-1), (PAA-2), (P-13), and (P-14), respectively, were obtained. In Table 1, the values for the tetracarboxylic acid derivative indicate the use ratio (mol%) of each compound used in the synthesis of the polymer with respect to the total amount of the tetracarboxylic acid derivative. The values for the diamine indicate the use ratio (mol%) of each compound used in the synthesis of the polymer with respect to the total amount of the diamine.

[0332] <Synthesis of Polyimide>

[0333] [Synthesis Example 2-2]

[0334] A solution containing 10 mass% of the polyamide acid was obtained by dissolving 100 mol parts of 2,3,5-tricarboxy cyclopentyl acetic dianhydride (compound (T-1)), 20 mol parts of the compound (DA-2), and 80 mol parts of the compound (DA-3) in N-methyl-2-pyrrolidone (NMP) and allowing the mixture to react at 40°C for 3 hours. To the obtained polyamide acid solution, 1 mol each of pyridine and acetic anhydride with respect to 1 mol of the tetracarboxylic dianhydride used in the polymerization was added, and a dehydration ring closure reaction was performed at 100°C for 8 hours. The reaction mixture after the completion of the reaction 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, whereby the polymer (P-2) was obtained. The imidization rate of the obtained polymer (P-2) was 68%.

[0335] <Synthesis of Polyamide Acid Ester>

[0336] [Synthesis Example 2-3]

[0337] In a 200 mL three-necked flask including a nitrogen introduction tube, a reflux cooling tube, and a thermometer, 22.42 g of a compound represented by the following formula (TA-3), 100 mL of tetrahydrofuran, and 0.79 g of pyridine were placed, and stirred under a stream of nitrogen to suspend. To this suspension, 15.14 g of β-methylallyl alcohol was added, and stirred at room temperature for 2 hours. Further, the reaction was carried out at 60°C for 8 hours, and a colorless transparent solution was obtained. This reaction solution was concentrated under reduced pressure at 60°C, and further vacuum dried to obtain a mixture of a compound represented by the following formula (DE-la) and a compound represented by the following formula (DE-lb) (hereinafter, referred to as "mixture (DE-la / b)"). 36.84 g.

[0338] [Chemical Formula 32]

[0339]

[0340] Further, in a 100 mL flask including a nitrogen introduction tube and a reflux cooling tube, 18.42 g of the mixture (DE-la / b) and 100 mL of toluene were placed, and stirred at 80°C for 30 minutes. Then, while stirring, it was cooled to room temperature, and further stirred at room temperature for 30 minutes. The obtained suspension was filtered, and washed twice with 5 mL of toluene. The obtained solid was vacuum dried at 60°C to obtain 15.47 g of the compound (DE-la) as a white powder (yield 84%).

[0341] In a 500 mL three-necked flask including a nitrogen introduction tube, a reflux cooling tube, and a thermometer, 14.74 g of the compound (DE-la), 80 mL of heptane, and 0.032 g of pyridine were placed, and stirred at 75°C under a stream of nitrogen. While slowly dropping 14.28 g of thionyl chloride over 20 minutes, foaming accompanying the progress of the reaction was confirmed. After the dropping was completed, the reaction was carried out at 75°C for 2 hours, and a colorless transparent solution was obtained. This reaction solution was concentrated under reduced pressure at 60°C, and excess thionyl chloride was distilled off. To the obtained liquid, 80 mL of heptane was added, and stirred at room temperature, and the precipitated insoluble component was removed by filtration. This filtrate was concentrated under reduced pressure at 60°C, and further dried under a high vacuum at 60°C for 4 hours to obtain 15.89 g of the compound represented by the following formula (DE-la) as a colorless transparent liquid (yield 98%).

[0342] [Chemical Formula 33]

[0343]

[0344] In a 50 ml three-necked flask containing a nitrogen inlet tube and a thermometer, 100 moles of compound (T-3), 70 moles of compound (DA-2), 30 moles of compound (DA-4), 57 g of NMP, and 24 g of triethylamine were placed. The mixture was cooled to approximately 10 °C, and 83 g of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) was added as a triazine dehydrating condensing agent. The reaction was carried out under a nitrogen atmosphere at room temperature for 24 hours. The resulting polymerization solution was diluted with NMP and slowly injected into methanol while stirring to allow it to solidify. The precipitated solid was recovered and washed twice with stirring in methanol. It was then vacuum dried at 60 °C to obtain a white polyamic acid ester powder (hereinafter referred to as "polymer (P-3)"). The polymer has a number average molecular weight Mn of 14,000 and a molecular weight distribution Mw / Mn of 2.8.

[0345] [Table 1]

[0346]

[0347] <Synthesis of Polyorganosiloxanes>

[0348] [Synthesis example 2-5]

[0349] In a reaction vessel including a stirrer, thermometer, dropping funnel, and reflux condenser, 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. Then, 100 g of pure water was slowly added dropwise, and the mixture was stirred at 80°C for 6 hours. The organic layer was then removed and washed with a 0.2% (w / w) ammonium nitrate aqueous solution until the washing water was neutral. The mixture was then concentrated to obtain an epoxy-containing polyorganosiloxane (EPS-1) as a viscous, transparent liquid. The Mw of the epoxy-containing polyorganosiloxane (EPS-1) was 2,200, and the epoxy equivalent was 186 g / mol.

[0350] Next, in a 100 mL three-necked flask, the epoxy group-containing polyorganosiloxane (EPS-1) 8.0 g obtained in the above, methyl isobutyl ketone 26 g, the compound (CA-1) 15.3 g, and a product with the trade name "UCAT 18X" (a quaternary amine salt manufactured by San-Apro Co., Ltd.) 0.10 g were put, and the reaction was performed under stirring at 80°C for 12 hours. After the completion of the reaction, the reaction mixture was put into methanol, and the precipitate formed was recovered, dissolved in ethyl acetate, and subjected to water washing three times, and then the solvent was distilled off, whereby 23.2 g of a polymer (P-4) was obtained as a white powder. The weight average molecular weight Mw of the polymer (P-4) was 14,100.

[0351] < Synthesis of addition polymer >

[0352] [Synthesis Example 2-6]

[0353] Under nitrogen, a 100 mL two-necked flask was charged with the compound (M-1) 9.0 g, the compound (M-9) 3.0 g, and the compound (M-10) 1.8 g as polymerization monomers; 2,2'-azobis(2,4-dimethylvaleronitrile) 0.70 g as a radical polymerization initiator; 2,4-diphenyl-4-methyl-1-pentene 0.20 g as a chain transfer agent; and N-methyl-2-pyrrolidone (NMP) 50 mL as a solvent, and polymerization was performed at 70°C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and vacuum-dried at room temperature for 8 hours, whereby the target polymer (P-5) was obtained. The weight average molecular weight Mw determined by GPC and in terms of polystyrene was 42,000, and the molecular weight distribution Mw / Mn was 2.1.

[0354] [Synthesis Examples 2-7 to 2-10, Comparative Synthesis Example 1, Comparative Synthesis Example 2, Comparative Synthesis Example 5]

[0355] The same operation as in Synthesis Example 2-6 was performed except that the kind and amount of the polymerization monomers used were changed as described in Table 2 below, whereby the polymer (P-6) to the polymer (P-9), the polymer (P-11), the polymer (P-12), and the polymer (P-15) were obtained. In Table 2, the numerical values of the polymerization monomers indicate the use ratio (mole %) of each compound used in the synthesis of the polymer with respect to the total amount of the polymerization monomers.

[0356] [Table 2]

[0357]

[0358] 3. Manufacture of liquid crystal alignment agent and liquid crystal display device, and evaluation

[0359] [Example 1]

[0360] (1) Preparation of liquid crystal alignment agent

[0361] In a container into which 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) were put, NMP and butyl cellosolve (BC) were added as solvents to prepare a solution having a solvent composition of NMP / BC = 50 / 50 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered using a filter having a pore size of 1 μm, thereby preparing a liquid crystal alignment agent (AL-1).

[0362] (2) Production of liquid crystal display element of optical FFS type

[0363] A glass substrate having a 2-system metal electrode (electrode A and electrode B) containing chromium patterned in a comb shape and capable of independently applying a voltage to the electrode A and the electrode B was prepared. The glass substrate and a facing glass substrate on which no electrode was provided were set as a pair, and the liquid crystal alignment agent (AL-1) prepared in the above was applied to the face of the glass substrate having the electrode and one face of the facing glass substrate using a spin coater. Subsequently, after pre-baking using a hot plate at 80°C for 1 minute, heating (post-baking) was performed using an oven in which nitrogen substitution was performed at 200°C for 1 hour, thereby forming a coating film having an average film thickness of 0.08 μm.

[0364] This operation was repeated to obtain a pair (two pieces) of glass substrates having a coating film on a transparent conductive film. The coating film obtained in the above was subjected to photo-alignment treatment by irradiating polarized ultraviolet rays containing bright lines at 313 nm at 2,000 J / cm2from the normal line direction of the substrate using a Hg-Xe lamp and a Glan-Taylor prism. 2 In addition, this irradiation amount was a value measured using a light meter measured on the basis of a wavelength of 313 nm.

[0365] Subsequently, one of the pair of substrates on which the liquid crystal alignment film was formed was overlapped and pressure-bonded to the other substrate in a manner that the liquid crystal alignment film faces each other after applying an epoxy resin adhesive to which alumina balls having a diameter of 3.5 μm were added to the outer edge of the face on which the liquid crystal alignment film was formed, and hardening the adhesive. Subsequently, after filling a liquid crystal composition (manufactured by Merck, MLC-6221) between the pair of substrates from a liquid crystal injection port, the liquid crystal injection port was sealed using an acrylic-based photo-hardening adhesive, thereby obtaining a liquid crystal cell. Furthermore, polarizing plates were attached to the outer sides of the substrates in the liquid crystal cell in a manner that the polarizing directions of the two pieces of polarizing plates are orthogonal to each other.

[0366] (3) Evaluation of backlight reliability (BL reliability)

[0367] The liquid crystal display element manufactured above was subjected to a temperature of 27,000 cd / m². 2 After being placed on a high-brightness backlight for 500 hours, the changes in characteristics before and after backlight irradiation were evaluated using the method described below (3A).

[0368] (3A) Evaluate BL reliability based on lag rate of change

[0369] The delay of the liquid crystal display element was measured using an Axoscan instrument manufactured by Optoscience, and the rate of change of delay α before and after backlighting was calculated using the following formula (z-1). The smaller the rate of change α, the less likely the liquid crystal display element is to produce image retention even after long-term driving, and the better the reliability of the backlight. Cases with a rate of change α of less than 0.5% are defined as "best (◎)", cases with a rate of change α greater than 0.5% but less than 1% are defined as "good (○)", cases with a rate of change α greater than 1% but less than 2% are defined as "acceptable (Δ)", and cases with a rate of change α greater than 2% are defined as "unacceptable (×)".

[0370] α=Δθ / θ1…(z-1)

[0371] (In equation (z-1), Δθ represents the difference in delay before and after irradiation, and θ1 represents the delay before irradiation.)

[0372] The result is rated as "good (○)" in this embodiment.

[0373] [Example 2, Example 3 and Comparative Example 3]

[0374] Except for changing the formulation of the liquid crystal alignment agent as shown in Table 3, the liquid crystal alignment agent was prepared in the same manner as in Example 1. Furthermore, 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 the same evaluation was performed as in Example 1. The results are shown in Table 3.

[0375] [Example 4]

[0376] (1) Preparation of liquid crystal alignment agent

[0377] In a container into which 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) were put, NMP and BC were added as solvents to prepare a solution having a solvent composition of NMP / BC = 50 / 50 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered using a filter having a pore size of 1 μm to thereby prepare a liquid crystal aligning agent (AL-4).

[0378] (2) Manufacture of the liquid crystal display element of the homeotropic type (UV2A)

[0379] The liquid crystal aligning agent (AL-4) prepared in the above (1) was applied to the transparent electrode surface of a glass substrate having a transparent electrode including an ITO film using a spinner, and after pre-baking using a hot plate at 80°C for 1 minute, main baking was performed at 200°C for 40 minutes to form a coating film having a thickness of 0.08 μm. Subsequently, the surface of the coating film was irradiated with polarized ultraviolet rays including a bright line at 313 nm at room temperature for 200 J / m 2 from a direction inclined at 40° with respect to the normal line of the substrate using a Hg-Xe lamp and a Glan-Taylor prism. The same operation was repeated to produce a pair (two pieces) of substrates on which liquid crystal aligning films were formed.

[0380] The periphery of the surface of one of the two substrates on which liquid crystal aligning films were formed was coated with an epoxy adhesive into which alumina balls having a diameter of 3.5 μm were added by screen printing, and the pair of substrates was then pressure-bonded with the liquid crystal aligning film surfaces facing each other in such a manner that the projection direction of the optical axis of the ultraviolet rays irradiated to each substrate on the substrate surface became antiparallel. The adhesive was thermally cured at 150°C for 1 hour. Subsequently, a liquid crystal composition (manufactured by Merck Ltd., MLC-6608) was filled into the gap between the substrates from the liquid crystal injection port, and the liquid crystal injection port was sealed with an epoxy adhesive to thereby obtain a liquid crystal cell. Furthermore, in order to remove the flow alignment at the time of injection of the liquid crystal, the liquid crystal cell was heated at 150°C and then slowly cooled to room temperature. Next, polarizing plates were attached to the outer sides of the substrates in the liquid crystal cell in such a manner that the polarizing directions thereof were orthogonal to each other and that the projection direction of the optical axis of the ultraviolet rays irradiated at the time of formation of the liquid crystal aligning film on the substrate surface was at an angle of 45°.

[0381] (3) Evaluation of BL reliability

[0382] The liquid crystal display element produced in the above was left on a high-luminance backlight having a luminance of 27,000 cd / m 2 , for 500 hours, and the change in characteristics before and after irradiation with the backlight was evaluated by the method of (3B) below.

[0383] (3B) Evaluation of BL reliability according to tilt recovery

[0384] The pretilt angle of liquid crystal was measured using Optipro manufactured by Shintech, and the pretilt angle before and after backlight irradiation was compared, whereby the BL reliability was evaluated. The case where the difference in pretilt angle after irradiation and before irradiation was 0.1 degrees or less was rated as "best (O)", the case where the difference was more than 0.1 degrees and 0.5 degrees or less was rated as "good (D)", the case where the difference was more than 0.5 degrees and 1.0 degrees or less was rated as "fair (A)", and the case where the difference was more than 1.0 degrees was rated as "not good (X)". As a result, in this example, the evaluation was "fair (A)".

[0385] [Examples 5 to 10 and Comparative Examples 1, 2, 4, 5]

[0386] The 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 alignment type liquid crystal display element was manufactured in the same manner as in Example 4, and the same evaluation as in Example 4 was performed. The results thereof are shown in Table 3.

[0387] [Table 3]

[0388]

[0389] From the above results, it was found that in Examples 1 to 10 in which the liquid crystal alignment agent containing the polymer (P) was prepared, the liquid crystal alignment property was good even after long-time irradiation of backlight, and the BL reliability was excellent. In particular, in Examples 1 to 10 in which the polymer (P) in which R β Example 7 in which the polymer (P-7) in which R β Example 8 in which the polymer (P-8) in which R β Example 9 in which the polymer (P-9) in which R β Example 10 in which the polymer (P-10) in which R

[0390] On the other hand, in Comparative Examples 1 to 5 in which the liquid crystal alignment agent not containing the polymer (P) was used, the evaluation of BL reliability was not good. In addition, in Comparative Example 5 in which the polymer (P-15) in which an ester group (-COOMe) was introduced to the β position in the cinnamate structure was used, the evaluation of BL reliability was not good, and as a reason therefor, it was presumed that this was due to the influence of decarboxylation of the ester group (-COOMe) due to post-baking at high temperature.

[0391] [Example 11]

[0392] (1) Preparation of liquid crystal alignment agent

[0393] Using the polymer (P-9) obtained in Synthesis Examples 2-10, a liquid crystal alignment agent (AL-11) was prepared by the same composition and preparation method as in Example 9.

[0394] (2) Manufacturing and evaluation of liquid crystal display devices

[0395] Manufacturing corresponds to Figure 2 A liquid crystal display device. First, a TFT substrate with pixel electrodes and a CF substrate with opposing electrodes are prepared. As the pixel electrodes of the TFT substrate and the opposing electrodes of the CF substrate, full-surface electrodes without slits are used. The liquid crystal alignment agent (AL-11) prepared in (1) is coated on each electrode arrangement surface of the TFT substrate and the CF substrate by spin casting. After pre-baking at 80°C for 1 minute, it is baked at 230°C for 40 minutes to make the final film thickness 120 nm. Then, the coating film (liquid crystal alignment film) formed on the TFT substrate is scanned and exposed. Regarding scanning exposure, according to Figure 2 (a)~ ​ (c) is achieved by forming four domains with different orientations of liquid crystal molecules within a single pixel, using 20 mJ / cm 2 The intensity was subjected to a total of four linear polarizations at 313 nm. On the other hand, the liquid crystal alignment film formed on the CF substrate using a liquid crystal alignment agent (AL-11) was not exposed.

[0396] Subsequently, a nematic liquid crystal having a negative dielectric anisotropy was dropped on a formation surface of a liquid crystal alignment film of the TFT substrate, and a thermosetting epoxy resin was disposed as a sealing material on an outer edge portion of the CF substrate. Then, the TFT substrate and the CF substrate were bonded in such a manner that the alignment film surfaces of the TFT substrate and the CF substrate were located on the inner side. Subsequently, the epoxy resin was hardened by heating at 130°C for 1 hour, thereby obtaining a liquid crystal cell. The transmittance when the obtained liquid crystal cell was driven by an alternating current (AC) of 6 V was measured. As for the evaluation of the transmittance, an Expert Liquid Crystal Display (LCD) manufactured by Link Global 21 Co., Ltd. was used and the calculation was performed by simulation. As the calculation conditions, the following liquid crystal properties were applied: Δε = 3, Ne = 1.6, No = 1.5, cell gap: 3.2 μm, pretilt angle: measured value (TFT substrate side: 88.0°, CF substrate side: 90.0°), and the transmittance was evaluated from the result of applying a voltage of 6 V. In the case where the calculated value of the transmittance was less than 0.275, it was evaluated as "OK (Δ)", in the case where it was 0.275 or more and less than 0.280, it was evaluated as "Good (O)", in the case where it was 0.280 or more and less than 0.285, it was evaluated as "Excellent (◎)", and in the case where it was 0.285 or more, it was evaluated as "Best (◎◎)". In addition, the liquid crystal display device produced in the above was left on a high-luminance backlight of 27,000 cd / m2for 500 hours, and the change in characteristics (BL reliability based on tilt recovery) before and after irradiation of the backlight was evaluated by the method of (3B). The results are shown in Table 4. 2

[0397] [Comparative Example 6 and Reference Example 1]

[0398] A liquid crystal alignment agent was produced in the same manner as in Example 11, except that the polymer used was changed as shown in Table 4. In addition, using the produced liquid crystal alignment agent, a liquid crystal display device was produced 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.

[0399] [Table 4]

[0400]

[0401] ​As shown in Table 4, the transmittance of Example 11 using the liquid crystal aligning agent containing the polymer (P) was high, and the BL reliability was also excellent. In contrast, the transmittance and the BL reliability of Comparative Example 6 using the liquid crystal aligning agent not containing the polymer (P) were both inferior to those of Example 11. Further, in Reference Example 1 using the polymer containing the partial structure having a substituent (methyl) at the a-position of the carbonyl carbon in the formula (1) instead of the β-position, the evaluation of the transmittance was "O", and the evaluation of the BL reliability based on the tilt recovery was "O". From these results, it was clear that the transmittance and the BL reliability of the liquid crystal display device could be made more excellent by the liquid crystal aligning agent containing the polymer (P).

Claims

1. A liquid crystal alignment agent comprising a polymer (P) having a partial structure represented by the following formula (1), In formula (1), R β is 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 , R 12 , and R 13 are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms; R α is a hydrogen atom; X 1 is an oxygen atom or -NR 5 -; R 5 is a hydrogen atom, 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, an aralkyl group having 6 to 10 carbon atoms, a t-butyloxycarbonyl group, a benzyloxycarbonyl group, a 1,1-dimethyl-2-halogenated ethyloxycarbonyl group, an allyloxycarbonyl group, or a 2-(trimethylsilyl)ethyloxycarbonyl group; R 1 is 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 alkoxy silyl group, or an ester group; n is an integer of 0 to 4; and m is 0 or 1. " indicates a bond.

2. The liquid crystal aligning agent according to claim 1, wherein the polymer (P) has the partial structure represented by the 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 a polyamide acid, a polyamide acid ester, a polyimide, a polyorganosiloxane, and an addition polymer.

4. The liquid crystal aligning agent according to claim 1, wherein the polymer (P) has the partial structure represented by the formula (1) in a 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 a polyamide acid, a polyamide acid ester, and a 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 a polyamide acid, a polyamide acid ester, a polyimide, a polyorganosiloxane, and an addition polymer.

7. The liquid crystal alignment agent according to claim 1, further comprising a polymer (Q) not having the partial structure represented by the formula (1).

8. The liquid crystal aligning agent according to claim 7, wherein the polymer (Q) is at least one selected from the group consisting of a polyamide acid, a polyamide acid ester, a polyimide, and an addition polymer.

9. A method for producing a liquid crystal alignment film, comprising: a step of forming a coating film by applying the liquid crystal alignment agent according to any one of claims 1 to 8 on a substrate; and a step of performing light irradiation on the coating film.

10. A liquid crystal alignment film formed using the liquid crystal alignment agent according to any one of claims 1 to 8.

11. A liquid crystal element comprising the liquid crystal alignment film according to claim 10.

12. A liquid crystal display device which is a liquid crystal display device having a plurality of pixels, and which comprises: 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, and aligning the liquid crystal molecules; and a second alignment film formed on the second substrate, and aligning the liquid crystal molecules, at least one of the first alignment film and the second alignment film is a photoalignment film, each of 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 alignment directions of the liquid crystal molecules differ from each other, and the first alignment region, the second alignment region, the third alignment region, and the fourth alignment region are arranged in a longitudinal direction of the pixel, of the alignment direction of the first alignment region, the alignment direction of the second alignment region, the alignment direction of the third alignment region, and the alignment direction of the fourth alignment region, a difference between any two alignment directions is substantially equal to an integer multiple of 90 degrees, the plurality of pixels are arranged in a short direction of the pixel in such a manner that the alignment directions of the alignment regions adjacent to each other in the short direction of the pixel 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, the photoalignment film is formed using the liquid crystal alignment agent according to any one of claims 1 to 6.

13. A polymer having a partial structure represented by the following formula (1), ###0003### 14. The polymer according to claim 13, wherein the polymer has a structure represented by the following formula ( In formula (1), R β is an alkyl group having 1 to 3 carbons, a fluoroalkyl group having 1 to 3 carbons, a trialkylsilyl group, or -NR 12 R 13 , R 12 , and R 13 are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbons; R α is a hydrogen atom; X 1 is an oxygen atom or -NR 5 -; R 5 is a hydrogen atom, an alkyl group having 1 to 6 carbons, a cycloalkyl group having 4 to 10 carbons, an aryl group having 6 to 10 carbons, an aralkyl group having 6 to 10 carbons, a t-butyloxycarbonyl group, a benzyloxycarbonyl group, a 1,1-dimethyl-2-halogenated ethyloxycarbonyl group, an allyloxycarbonyl group, or a 2- (trimethylsilyl)ethyloxycarbonyl group; R 1 is an alkyl group having 1 to 5 carbons, an alkoxy group having 1 to 5 carbons, a halogen atom, a hydroxyl group, a carboxyl group, an amino group, a cyano group, an alkylsilyl group, an alkoxy silyl group, or an ester group; n is an integer of 0 to 4; and m is 0 or 1. " indicates a bond.

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