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

Abstract

To provide a liquid crystal aligning agent which allows for producing a liquid crystal display element that offers good contrast and after image characteristics and is capable of maintaining a high voltage retention rate even after being exposed to strong light for a prolonged period.SOLUTION: A liquid crystal aligning agent is provided, containing polymers, at least one of which being a polymer obtained by reacting tetracarboxylic acid dianhydrides with diamines, where the tetracarboxylic acid dianhydride contain at least one selected from a group consisting of a compound represented by a formula (1) and a derivative compound thereof. In formula (1), -X- independently represents a single bond, -O-, -S-, or -NR1-; R1 represents hydrogen or an alkyl group having 1 to 4 carbon atoms; n independently represents an integer of 1 to 5; and m represents an integer of 1 to 3. A group having a bond position not fixed to any of the carbon atoms constituting a ring indicates that bonding can be made to any of bondable carbons of the ring.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element using the same. More specifically, the present invention relates to a liquid crystal alignment agent for forming a photo-alignment type liquid crystal alignment film (hereinafter sometimes abbreviated as photo-alignment film), a photo-alignment type liquid crystal alignment film formed using the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film. Furthermore, the present invention relates to a polymer such as polyamic acid used in the liquid crystal alignment agent, and a tetracarboxylic dianhydride that is a raw material thereof. [Background technology]

[0002] Liquid crystal display elements are known to have various driving methods, such as TN (Twisted Nematic) mode, STN (Super Twisted Nematic) mode, IPS (In-Plane Switching) mode, FFS (Fringe Field Switching) mode, and vertical alignment type VA (Multi-domain Vertical Alignment) mode. These liquid crystal display elements are applied to image display devices of various electronic devices such as televisions and mobile phones, and development is being carried out with the aim of further improving the display quality. Specifically, the performance of liquid crystal display elements is improved not only by improving the driving method and element structure, but also by the components used in the elements. Among the components used in liquid crystal display elements, the liquid crystal alignment film is one of the important materials related to the display quality, and research on this liquid crystal alignment film is being actively carried out in order to meet the demand for high-quality liquid crystal display elements.

[0003] Here, the liquid crystal alignment film is provided on a pair of substrates provided on both sides of the liquid crystal layer of the liquid crystal display element in contact with the liquid crystal layer, and has the function of aligning the liquid crystal molecules constituting the liquid crystal layer with a certain regularity relative to the substrates. By using a liquid crystal alignment film with high liquid crystal alignment properties, a liquid crystal display element with high contrast and improved afterimage characteristics can be realized (see, for example, Patent Documents 1 and 2).

[0004] Currently, solutions (varnishes) in which polyamic acid, soluble polyimide, or polyamic acid ester is dissolved in an organic solvent are mainly used to form such liquid crystal alignment films. To form liquid crystal alignment films using these varnishes, the varnish is applied to a substrate, and the coating is solidified by heating or the like to form a polyimide-based liquid crystal alignment film, and an alignment treatment suitable for the above-mentioned display mode is performed as necessary. As alignment treatment methods, there are a rubbing method in which the surface of the alignment film is rubbed with a cloth or the like to align the direction of the polymer molecules, and a photoalignment method in which the alignment film is irradiated with linearly polarized ultraviolet light to cause photochemical changes such as photoisomerization and dimerization in the polymer molecules to give the film anisotropy. Of these, the photoalignment method has the advantages of being more uniform in alignment than the rubbing method, not scratching the film because it is a non-contact alignment treatment method, and reducing causes of display defects in liquid crystal display elements such as dust generation and static electricity.

[0005] As examples of liquid crystal alignment films produced using such photo-alignment methods, Patent Documents 1 to 6, for example, describe the use of diaminoazobenzene or the like as a raw material and the application of photoisomerization technology to obtain photo-alignment films with large anchoring energy and good liquid crystal alignment properties. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2010-197999 A [Patent Document 2] International Publication No. 2013 / 157463 [Patent Document 3] JP 2005-275364 A [Patent Document 4] JP 2007-248637 A [Patent Document 5] JP 2009-069493 A [Patent Document 6] International Publication No. 2015 / 016118 Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, the demand for high-quality liquid crystal display elements has been increasing, and there is a demand for reliability that can maintain contrast, image retention, and a high voltage holding ratio (VHR) for a long period of time. Maintaining a high voltage holding ratio is important to prevent a decrease in display quality. On the other hand, in consideration of outdoor use, there is also a demand for the brightness of the backlight, which serves as the light source, to be higher than that of previous models. In situations where the display is exposed to such high-brightness backlights, it is important to improve the VHR reliability against light, which is a particularly important issue for photo-alignment films, which generally have inferior electrical properties compared to rubbed alignment films.

[0008] Therefore, the inventors have conducted intensive research with the objectives of providing a liquid crystal alignment film capable of forming a liquid crystal display element having good contrast and afterimage characteristics, and maintaining a high voltage retention rate and no deterioration in display quality even when exposed to strong light for a long period of time, and of providing a liquid crystal alignment agent capable of forming such a liquid crystal alignment film. [Means for solving the problem]

[0009] As a result of intensive research to solve the above problems, the present inventors have found that by using tetracarboxylic dianhydrides represented by formula (1), a liquid crystal alignment film with high liquid crystal alignment properties can be obtained, and that by using this liquid crystal alignment film, a liquid crystal display element can be formed which has good contrast and afterimage characteristics, and which maintains a high voltage retention rate and does not deteriorate in display quality even when exposed to strong light for a long period of time, thereby completing the present invention. The present invention includes the following configurations.

[0010] [1] A liquid crystal alignment agent comprising a polymer, at least one of the polymers being a polymer obtained by reacting tetracarboxylic dianhydrides with diamines, the tetracarboxylic dianhydrides comprising at least one selected from the group consisting of a compound represented by formula (1) and a compound derived therefrom. In formula (1), -X- is independently a single bond, -O-, -S-, or -NR 1 - and R 1 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, n is independently an integer of 1 to 5, and m is an integer of 1 to 3, and a group that is not fixedly bonded to any of the carbon atoms constituting the ring can be bonded to any available carbon atom in the ring. [2] The liquid crystal aligning agent according to [1], wherein the compound represented by formula (1) is at least one selected from the group consisting of compounds represented by formulas (2) to (4). TIFF0007673614000002.tif87110In formulas (2) to (4), m is an integer of 1 to 3, and in formula (4), n is independently an integer of 2 to 5. [3] The liquid crystal aligning agent according to [1] or [2], wherein the raw material composition used as a raw material for the polymer obtained by reacting the tetracarboxylic dianhydrides with diamines contains at least one selected from the group consisting of the compound represented by formula (1) and its derivative compounds, and a compound having a photoreactive structure. [4] The liquid crystal aligning agent according to [3], wherein the compound having a photoreactive structure is a compound having a photodecomposition structure, a compound having a photoisomerization structure, or a compound having a photodimerization structure. [5] The liquid crystal aligning agent according to [4], wherein the compound having a photoisomerizable structure is a compound represented by the following formula (V-2): TIFF0007673614000003.tif31110 In formula (V-2), X is an alkylene group having 1 to 12 carbon atoms, and one or more non-adjacent -(CH2)2- in the alkylene group may be replaced with -O- or -NH-, R a and R b each independently represents a hydrogen atom, -CH3, -OCH3, -CF3, -F, -COOCH3, or a monovalent group represented by formula (P1-1) or formula (P1-2), R ceach independently represents a hydrogen atom, -CH3, -OCH3, -CF3, -F, or a monovalent group represented by formula (P1-1) or formula (P1-2), j is 0 or 1, and a to c each independently represent an integer of 0 to 2, TIFF0007673614000004.tif2674 In formula (P1-1) and formula (P1-2), R d , R e and R f each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkanoyl group, a substituted or unsubstituted alkoxycarbonyl group, or a substituted or unsubstituted arylcarbonyl group; R d , R e and R f may be the same or different, * represents the bonding position to the benzene ring in formula (V-2), In formula (V-2), a group that is not fixed to any of the carbon atoms constituting the ring indicates that it can be bonded to any available carbon atom in the ring. [6] A liquid crystal alignment film formed from the liquid crystal aligning agent according to any one of [1] to [5]. [7] A liquid crystal display element having the liquid crystal alignment film according to [6]. [8] A method for producing a liquid crystal alignment film, comprising the steps of applying the liquid crystal aligning agent according to any one of [1] to [5] to a substrate, and irradiating the coating with polarized ultraviolet light. [9] A compound represented by formula (1) or a derivative compound thereof: TIFF0007673614000005.tif26110In formula (1), -X- is independently a single bond, -O-, -S-, or -NR 1 - and R 1 is hydrogen or an alkyl group having 1 to 4 carbon atoms, n is independently an integer of 1 to 5, and m is an integer of 1 to 3. A group that is not fixedly bonded to any of the carbon atoms constituting a ring indicates that it can be bonded to any available carbon atom in the ring.

[10] The compound according to [9] or a derivative compound thereof, wherein the compound represented by formula (1) is a compound represented by any one of formulas (2) to (4). TIFF0007673614000006.tif87110In formulas (2) to (4), m is an integer of 1 to 3, and in formula (4), n is independently an integer of 2 to 5.

[11] A polymer obtained by reacting tetracarboxylic dianhydrides with diamines, the tetracarboxylic dianhydrides including at least one selected from the group consisting of compounds represented by formula (1) and derivative compounds thereof. In formula (1), -X- is independently a single bond, -O-, -S-, or -NR 1 - and R 1 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, n is independently an integer of 1 to 5, and m is an integer of 1 to 3, and a group that is not fixedly bonded to any of the carbon atoms constituting the ring can be bonded to any available carbon atom in the ring. Effect of the Invention

[0011] By using the liquid crystal aligning agent of the present invention, a liquid crystal alignment film with high liquid crystal alignment properties can be obtained. In addition, by using this liquid crystal alignment film, a liquid crystal display device can be realized that has excellent afterimage characteristics and contrast, and maintains a high voltage retention rate and does not deteriorate in display quality even when exposed to strong light for a long period of time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described in detail below. The following description of the constituent elements may be based on a representative embodiment or specific example, but the present invention is not limited to such an embodiment. As an embodiment of the present invention, the liquid crystal aligning agent of the present invention can be used as a liquid crystal aligning agent for photo-alignment by using a compound having a photoreactive structure. The liquid crystal aligning agent for photo-alignment is a liquid crystal aligning agent that can be given anisotropy by forming a film of the liquid crystal aligning agent on a substrate and irradiating it with polarized ultraviolet light, and is sometimes simply referred to as a "liquid crystal aligning agent" in this specification. In addition, an alignment film formed from a liquid crystal aligning agent for photo-alignment may be referred to as a photo-alignment film or simply as an alignment film. In addition, in the present invention, "tetracarboxylic dianhydrides" refers to tetracarboxylic dianhydrides, tetracarboxylic diesters, or tetracarboxylic diester dihalides. In addition, in the present invention, diamines and dihydrazides are sometimes referred to as "diamines".

[0013] <Compound represented by formula (1) and its derivative compound> The liquid crystal aligning agent of the present invention is a liquid crystal aligning agent containing a polymer obtained by reacting tetracarboxylic dianhydrides with diamines, and the tetracarboxylic dianhydrides contain at least one selected from the group consisting of compounds represented by the following formula (1) and derivative compounds thereof: TIFF0007673614000008.tif26110In formula (1), -X- is independently a single bond, -O-, -S-, or -NR 1 - and R 1 is hydrogen or an alkyl group having 1 to 4 carbon atoms, n is independently an integer of 1 to 5, and m is an integer of 1 to 3. A group that is not fixedly bonded to any of the carbon atoms constituting a ring indicates that it can be bonded to any available carbon atom in the ring.

[0014] The derivative compound of the compound represented by formula (1) is, for example, a tetracarboxylic acid diester or a tetracarboxylic acid diester dihalide derived from a tetracarboxylic acid dianhydride. In the present invention, the "compound represented by formula (1) and its derivative compound" may be collectively referred to as "tetracarboxylic acid dianhydrides represented by formula (1)".

[0015] By using the tetracarboxylic dianhydrides represented by formula (1) as the raw material for the polymer, it is possible to form a liquid crystal display element that has good contrast and image retention characteristics, and maintains a high voltage retention rate and does not deteriorate in display quality even when exposed to strong light for a long period of time. The reason for this is not entirely clear, but it is thought to be as follows.

[0016] When a polyimide alignment film is formed using tetracarboxylic dianhydrides represented by formula (1) as a polymer raw material, the imide structure and the conjugated system of the aromatic ring in formula (1) are not connected by the alkylene structure in formula (1), so the absorption coefficient of the polymer in the wavelength region of light irradiated from the backlight is smaller than that in the case of using an aromatic tetracarboxylic dianhydride in which a dicarboxylic anhydride is directly bonded to an aromatic ring. Therefore, when a liquid crystal alignment film is formed using a liquid crystal alignment agent containing a polymer using tetracarboxylic dianhydrides represented by formula (1) as a raw material and a liquid crystal display element is formed using this film, it is considered that the decrease in VHR of the liquid crystal display element caused by light irradiation can be suppressed.

[0017] However, if a tetracarboxylic dianhydride does not have an aromatic ring, it is thought that the decrease in VHR of a liquid crystal display element can be suppressed, but the liquid crystal alignment property is thought to decrease because the interaction between the liquid crystal alignment film and the liquid crystal molecules is weak. Therefore, when a liquid crystal display element is formed, there is a risk that the afterimage characteristic and contrast may deteriorate. In response to this, the present inventors introduced an aromatic ring into formula (1). In addition, the alkylene structure in formula (1) also plays a role in increasing the fluidity of the polymer, thereby increasing the anisotropy of the liquid crystal alignment film after the alignment treatment, and it was found that the structure of formula (1) can suppress the decrease in VHR and realize good contrast and afterimage characteristics.

[0018] In the compound represented by formula (1), the binding position of a group that is not fixed to any of the carbon atoms constituting a ring is preferably the para position in the ring in terms of orientation.

[0019] Examples of the tetracarboxylic dianhydrides represented by formula (1) include compounds represented by the following formulas (2) to (4) and compounds derived therefrom. TIFF0007673614000009.tif87110In formulas (2) to (4), m is an integer of 1 to 3, and in formula (4), n is independently an integer of 2 to 5.

[0020] The compound represented by formula (2) is specifically the compound represented by the following formulae (2-1) to (2-3). TIFF0007673614000010.tif59100

[0021] The compound represented by formula (3) is specifically the compound represented by the following formulae (3-1) to (3-3). TIFF0007673614000011.tif62105

[0022] The compound represented by formula (4) is specifically the compound represented by the following formulae (4-1) to (4-12). TIFF0007673614000012.tif112102 TIFF0007673614000013.tif110112 TIFF0007673614000014.tif122122

[0023] <Method for producing tetracarboxylic dianhydride represented by formula (1)> The method for producing the tetracarboxylic dianhydride represented by formula (1) of the present invention will be described below.

[0024] [Method for producing the compound represented by formula (2)] The compound represented by formula (2) is produced by steps 1-1 to 1-4. TIFF0007673614000015.tif82153 In formula (2A) and formula (2C), R 1 R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted arylmethyl group. 1 Specific examples of the alkyl group in R include a methyl group, an ethyl group, and a propyl group. 1 A specific example of the aryl group in R is a phenyl group. 1 Specific examples of the arylmethyl group in formula (2B) include a benzyl group, a 4-methoxybenzyl group, a 3,4-dimethoxybenzyl group, and a 2-naphthylmethyl group. 1 represents a leaving group. 1 Examples of the leaving group represented by the formula (2B), (2C), (2D), (2E), and (2) include halogen atoms such as bromine and iodine atoms, and sulfonyloxy groups such as methanesulfonyloxy, trifluoromethanesulfonyloxy, benzenesulfonyloxy, and p-toluenesulfonyloxy. In the formulas (2B), (2C), (2D), (2E), and (2), m is an integer of 1 to 3.

[0025] Step 1-1 is a reaction between a compound represented by formula (2A) and a compound represented by formula (2B), which is carried out in the presence of a base. Examples of the base include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, alkali metal hydrides such as sodium hydride, alkali metal alkoxides such as sodium methoxide and sodium ethoxide, and tetrabutylammonium hydroxide. There is no particular restriction on the amount of the base used, and it is sufficient to use 1 to 5 molar equivalents relative to the compound represented by general formula (2A) as a raw material.

[0026] The reaction in step 1-1 can be carried out in a solvent. As the solvent, any solvent that does not harm the reaction can be used, and examples thereof include ether solvents such as diethyl ether, diisopropyl ether, cyclopentyl methyl ether, dimethoxyethane, tetrahydrofuran (THF), and dioxane, nitrile solvents such as acetonitrile and propionitrile, aromatic solvents such as benzene, toluene, xylene, chlorobenzene, and dichlorobenzene, amide solvents such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide, dimethyl sulfoxide (DMSO), and water. These solvents may be used alone or in combination of two or more.

[0027] The reaction temperature in step 1-1 can be appropriately selected within the range of −78° C. to the reflux temperature of the solvent used. The reaction time varies depending on other conditions such as the reaction temperature, but is suitably 1 to 24 hours.

[0028] The compound represented by formula (2C) obtained by the reaction in step 1-1 may be subjected to the next reaction (step 1-2) without purification, or may be subjected to the next reaction after purification. Examples of the purification method include extraction, column chromatography, and recrystallization.

[0029] Step 1-2 is a hydrolysis reaction of the ester of the compound represented by formula (2C), and is carried out in the presence of a base. Examples of the base include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. There is no particular limitation on the amount of the base used, and it is sufficient to use 1 to 50 molar equivalents relative to the compound represented by general formula (2C) as the raw material.

[0030] The reaction in step 1-2 can be carried out in a solvent. As the solvent, any solvent that does not harm the reaction can be used, and examples thereof include ether solvents such as diethyl ether, diisopropyl ether, cyclopentyl methyl ether, dimethoxyethane, tetrahydrofuran (THF), and dioxane, nitrile solvents such as acetonitrile and propionitrile, aromatic solvents such as benzene, toluene, xylene, chlorobenzene, and dichlorobenzene, amide solvents such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide, alcohol solvents such as methanol, ethanol, and isopropanol, dimethyl sulfoxide (DMSO), and water. These solvents may be used alone or in combination of two or more.

[0031] The reaction temperature in step 1-2 can be appropriately selected from the range of room temperature to the reflux temperature of the solvent used. The reaction time varies depending on other conditions such as the reaction temperature, but is preferably 1 to 24 hours.

[0032] The compound represented by formula (2D) obtained by the reaction in step 1-2 may be subjected to the next reaction (step 1-3) without purification, or may be subjected to the next reaction after purification. Examples of the purification method include extraction, column chromatography, and recrystallization.

[0033] Step 1-3 is a decarboxylation reaction of the compound represented by formula (2D) and is carried out in the presence of an acid. Examples of the acid include mineral acids such as hydrochloric acid and sulfuric acid. There is no particular limitation on the amount of the acid used, and it is sufficient to use 1 to 5 molar equivalents relative to the compound represented by general formula (2D) as a raw material.

[0034] The reaction in step 1-3 can be carried out in a solvent. As the solvent, any solvent that does not harm the reaction can be used, and examples thereof include ether solvents such as diethyl ether, diisopropyl ether, cyclopentyl methyl ether, dimethoxyethane, tetrahydrofuran (THF), and dioxane, nitrile solvents such as acetonitrile and propionitrile, aromatic solvents such as benzene, toluene, xylene, chlorobenzene, and dichlorobenzene, amide solvents such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide, alcohol solvents such as methanol, ethanol, and isopropanol, dimethyl sulfoxide (DMSO), and water. These solvents may be used alone or in combination of two or more.

[0035] The reaction temperature in step 1-3 can be appropriately selected from the range of room temperature to the reflux temperature of the solvent used. The reaction time varies depending on other conditions such as the reaction temperature, but is preferably 1 to 24 hours.

[0036] The compound represented by formula (2E) obtained by the reaction in step 1-3 may be subjected to the next reaction (step 1-4) without purification, or may be subjected to the next reaction after purification. Examples of the purification method include extraction, column chromatography, and recrystallization.

[0037] Step 1-4 is a dehydration condensation reaction of the compound represented by formula (2E), which is carried out in the presence of an acid anhydride. Examples of the acid anhydride include acetic anhydride and trifluoroacetic anhydride. There is no particular limitation on the amount of the acid anhydride used, and it is sufficient to use 1 to 100 molar equivalents relative to the compound represented by general formula (2E) as a raw material.

[0038] The reaction in step 1-4 can be carried out in a solvent. As the solvent, any solvent that does not harm the reaction can be used, and examples thereof include ether solvents such as diethyl ether, diisopropyl ether, cyclopentyl methyl ether, dimethoxyethane, tetrahydrofuran (THF), and dioxane, nitrile solvents such as acetonitrile and propionitrile, aromatic solvents such as benzene, toluene, xylene, chlorobenzene, and dichlorobenzene, amide solvents such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide, and dimethyl sulfoxide (DMSO). An acid anhydride may be used as the solvent. These solvents may be used alone or in combination of two or more.

[0039] The reaction temperature in step 1-4 can be appropriately selected from the range of room temperature to reflux temperature. The reaction time varies depending on other conditions such as the reaction temperature, but is preferably 1 to 24 hours.

[0040] It is also preferable to purify the compound represented by formula (2) obtained in step 1-4, for example, by a conventional method such as silica gel column chromatography or recrystallization.

[0041] [Method for producing the compound represented by formula (3)] The compound represented by formula (3) is produced by steps 2-1 to 2-6. TIFF0007673614000016.tif92165 In formula (3A), formula (3C), formula (3E), and formula (3F), R 1 R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted arylmethyl group. 1 Specific examples of the alkyl group in R include a methyl group, an ethyl group, and a propyl group. 1 A specific example of the aryl group in R is a phenyl group. 1Specific examples of the arylmethyl group in formula (3B) include a benzyl group, a 4-methoxybenzyl group, a 3,4-dimethoxybenzyl group, and a 2-naphthylmethyl group. 2 represents a leaving group. 2 Examples of the leaving group represented by the formula (3D) include halogen atoms such as bromine and iodine atoms, and sulfonyloxy groups such as methanesulfonyloxy, trifluoromethanesulfonyloxy, benzenesulfonyloxy, and p-toluenesulfonyloxy. 3 represents a halogen or a sulfonyloxy group. 3 Examples of the halogen represented by the formula (3D) include iodine, chlorine, and bromine. 3 In the formulae (3D) to (3H) and (3), m is an integer of 1 to 3.

[0042] Step 2-1 is a reaction between a compound represented by formula (3A) and a compound represented by formula (3B), and for example, the above step 1-1 can be referred to.

[0043] Step 2-2 is a coupling reaction between a compound represented by formula (3C) and a compound represented by formula (3D), and is carried out in the presence of a catalyst, a ligand, a cocatalyst, and a base. Examples of the catalyst include palladium catalysts such as tetrakis(triphenylphosphine)palladium, bis(triphenylphosphine)palladium dichloride, palladium acetate, bis(dibenzylideneacetone)palladium, 1,1'-bis(diphenylphosphino)ferrocene dichloropalladium, and dichlorobis[di-t-butyl(p-dimethylaminophenyl)phosphino]palladium. There is no particular restriction on the amount of catalyst used, and it may be used in an amount of 0.001 to 1 molar equivalent relative to the compound represented by general formula (3C) as a raw material. Examples of the ligand include phosphines such as tri-tert-butylphosphine, tricyclohexylphosphine, triphenylphosphine, tri(2-furyl)phosphine, tri(o-tolyl)phosphine, and 1,1'-bis(diphenylphosphino)ferrocene. There is no particular limitation on the amount of the ligand used, and it is sufficient to use 0.001 to 1 molar equivalent to the compound represented by general formula (3C) as the raw material.

[0044] An example of the co-catalyst is copper iodide. There is no particular limit to the amount of the co-catalyst used, and it may be used in an amount of 0.001 to 1 molar equivalent to the compound represented by general formula (3C) as the raw material. Examples of the base include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate, potassium carbonate, and cesium carbonate, and amine compounds such as diethylamine, triethylamine, diisopropylamine, and diisopropylethylamine. There is no particular limit to the amount of the base used, and it may be used in an amount of 1 to 5 molar equivalent to the compound represented by general formula (3C) as the raw material.

[0045] The reaction in step 2-2 can be carried out in a solvent. As the solvent, any solvent that does not harm the reaction can be used, and examples thereof include ether solvents such as diethyl ether, diisopropyl ether, cyclopentyl methyl ether, dimethoxyethane, tetrahydrofuran (THF), and dioxane, nitrile solvents such as acetonitrile and propionitrile, aromatic solvents such as benzene, toluene, xylene, chlorobenzene, and dichlorobenzene, amide solvents such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide, dimethyl sulfoxide (DMSO), and water. The amine compound used as the base may be used as the solvent. These solvents may be used alone or in combination of two or more.

[0046] The reaction temperature in step 2-2 can be appropriately selected from the range of room temperature to the reflux temperature of the solvent used. The reaction time varies depending on other conditions such as the reaction temperature, but is preferably 1 to 24 hours.

[0047] The compound represented by formula (3E) obtained by the reaction in step 2-2 may be subjected to the next reaction (step 2-3) without purification, or may be subjected to the next reaction after purification. Examples of the purification method include extraction, column chromatography, and recrystallization.

[0048] Step 2-3 is catalytic reduction of the compound represented by formula (3E). Reduction is carried out using a Pd / C catalyst, Raney nickel, or the like under a hydrogen gas atmosphere.

[0049] The reaction in step 2-3 can be carried out in a solvent. As the solvent, any solvent that does not harm the reaction can be used, and examples thereof include ether solvents such as diethyl ether, diisopropyl ether, cyclopentyl methyl ether, dimethoxyethane, tetrahydrofuran (THF), and dioxane, aromatic solvents such as benzene, toluene, xylene, chlorobenzene, and dichlorobenzene, amide solvents such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide, alcohol solvents such as methanol, ethanol, and isopropanol, and dimethyl sulfoxide (DMSO). These solvents may be used alone or in combination of two or more.

[0050] The reaction temperature in step 2-3 can be appropriately selected from the range of room temperature to the reflux temperature of the solvent used. The reaction pressure can be appropriately selected from the range of atmospheric pressure to 1 MPa. The reaction time varies depending on other conditions such as the reaction temperature, but is preferably 1 to 120 hours.

[0051] Step 2-4 is a hydrolysis reaction of the ester of the compound represented by formula (3F), and for example, the above-mentioned Step 1-2 can be referred to.

[0052] Step 2-5 is a decarboxylation reaction of the compound represented by formula (3G), and for example, the above-mentioned Step 1-3 can be referred to.

[0053] Step 2-6 is a dehydration condensation reaction of the compound represented by formula (3H), and for example, the above-mentioned Step 1-4 can be referred to.

[0054] [Method for producing the compound represented by formula (4)] The compound represented by formula (4) is produced by steps 3-1 to 3-5. TIFF0007673614000017.tif122153In equations (4A), (4C), and (4E), R 1R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted arylmethyl group. 1 Specific examples of the alkyl group in R include a methyl group, an ethyl group, and a propyl group. 1 A specific example of the aryl group in R is a phenyl group. 1 Specific examples of the arylmethyl group in formula (4B) and formula (4C) include a benzyl group, a 4-methoxybenzyl group, a 3,4-dimethoxybenzyl group, and a 2-naphthylmethyl group. 4 and L 5 represents a leaving group. L in formula (4B) and formula (4C) 4 and L 5 Examples of the leaving group represented by the formula (4B), (4C), (4E) to (4G), and (4) include halogen atoms such as bromine and iodine atoms, and sulfonyloxy groups such as methanesulfonyloxy, trifluoromethanesulfonyloxy, benzenesulfonyloxy, and p-toluenesulfonyloxy. In the formulas (4B), (4C), (4E) to (4G), and (4), n is an integer of 2 to 5. In the formulas (4D) to (4G), and (4), m is an integer of 1 to 3.

[0055] Step 3-1 is a reaction between a compound represented by formula (4A) and a compound represented by formula (4B), and for example, the above step 1-1 can be referred to.

[0056] Step 3-2 is etherification of the compound represented by formula (4C) and the compound represented by formula (4D), and is carried out in the presence of a base and an iodide. Examples of the base include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate, potassium carbonate, and cesium carbonate, and amine compounds such as diethylamine, triethylamine, diisopropylamine, and diisopropylethylamine. There is no particular limit to the amount of the base used, and it may be used in an amount of 1 to 5 molar equivalents relative to the compound represented by general formula (4C) as a raw material. Examples of the iodide include sodium iodide and potassium iodide. There is no particular limit to the amount of the iodide used, and it may be used in an amount of 0.01 to 2 molar equivalents relative to the compound represented by general formula (4C) as a raw material.

[0057] The reaction in step 3-2 can be carried out in a solvent. As the solvent, any solvent that does not harm the reaction can be used, and examples thereof include ether solvents such as diethyl ether, diisopropyl ether, cyclopentyl methyl ether, dimethoxyethane, tetrahydrofuran (THF), and dioxane, nitrile solvents such as acetonitrile and propionitrile, aromatic solvents such as benzene, toluene, xylene, chlorobenzene, and dichlorobenzene, amide solvents such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide, dimethyl sulfoxide (DMSO), and water. The amine compound used as the base may be used as the solvent. These solvents may be used alone or in combination of two or more.

[0058] Step 3-3 is a hydrolysis reaction of the ester of the compound represented by formula (4E), and for example, the above-mentioned Step 1-2 can be referred to.

[0059] Step 3-4 is a decarboxylation reaction of the compound represented by formula (4F), and for example, the above-mentioned Step 1-3 can be referred to.

[0060] Step 3-5 is a dehydration condensation reaction of the compound represented by formula (4G), and for example, the above-mentioned Step 1-4 can be referred to.

[0061] The derivative compounds of the compounds represented by formulae (2) to (4) can be produced from the tetracarboxylic dianhydrides represented by formulae (2) to (4). The tetracarboxylic diesters can be obtained by reacting the tetracarboxylic dianhydrides with two equivalents of alcohol to open the ring, and the tetracarboxylic diester dichlorides can be obtained by reacting the tetracarboxylic diesters with two equivalents of a chlorinating agent (e.g., thionyl chloride, etc.).

[0062] <Type of polymer> The polymer used in the liquid crystal alignment agent of the present invention is at least one selected from the group consisting of polyamic acid, polyimide, partial polyimide, polyamic acid ester, polyamic acid-polyamide copolymer, and polyamideimide, which contain at least one tetracarboxylic dianhydride represented by formula (1) as a raw material. In this specification, polyimide, partial polyimide, polyamic acid ester, polyamic acid-polyamide copolymer, and polyamideimide are sometimes referred to as polyamic acid derivatives.

[0063] The polyamic acid and the polyamic acid derivatives will be described in detail below.

[0064] Here, the polyamic acid is a polymer synthesized by a polymerization reaction between a tetracarboxylic dianhydride represented by formula (AN) and a diamine represented by formula (DI), and has a constitutional unit represented by formula (PAA). When a liquid crystal alignment agent containing a polyamic acid is heated and baked in the process of forming a liquid crystal alignment film, the polyamic acid is imidized, and a polyimide liquid crystal alignment film having a constitutional unit represented by formula (PI) can be formed. TIFF0007673614000018.tif36140 TIFF0007673614000019.tif3659

[0065] In formula (AN), formula (PAA), and formula (PI), X 1 is a tetravalent organic group. In formula (DI), formula (PAA), and formula (PI), X 2 is a divalent organic group. X 1 For the preferred range and specific examples of X, reference can be made to the formula (1), the compounds having the photoreactive structure shown below, and the corresponding structures of the tetracarboxylic dianhydrides shown in the section on other tetracarboxylic dianhydrides shown below. 2 For the preferred range and specific examples of the above, reference can be made to the descriptions of the corresponding structures of the diamines or dihydrazides described in the sections on compounds having a photoreactive structure and other diamines below.

[0066] The polyamic acid derivative is a polymer whose characteristics are modified by replacing a part of the polyamic acid with another atom or atomic group, and is preferably one whose solubility in a solvent used for a liquid crystal alignment agent is increased. Specific examples of such polyamic acid derivatives include 1) polyimides in which all amino groups and carboxyl groups of a polyamic acid are subjected to a dehydration ring-closing reaction, 2) partial polyimides in which a part of the polyamic acid is subjected to a dehydration ring-closing reaction, 3) polyamic acid esters in which the carboxyl groups of a polyamic acid are converted into esters, 4) polyamic acid-polyamide copolymers obtained by replacing a part of the acid dianhydride contained in a tetracarboxylic dianhydride compound with an organic dicarboxylic acid and reacting the resulting mixture, and 5) polyamideimides in which a part or all of the polyamic acid-polyamide copolymer is subjected to a dehydration ring-closing reaction. Among these derivatives, for example, polyimides having a constitutional unit represented by the above formula (PI) can be mentioned, and polyamic acid esters having a constitutional unit represented by the following formula (PAE) can be mentioned. TIFF0007673614000020.tif4661 In the formula (PAE), X 1 is a tetravalent organic group, and X 2 is a divalent organic group, and each Y is independently an alkyl group. 1 , X 2The preferred range and specific examples of X in formula (PAA) are 1 , X 2 For Y, a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms is preferable, and a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, or a tertiary butyl group is more preferable.

[0067] The tetracarboxylic dianhydrides and diamines used in the synthesis of the polyamic acid may each be one type or two or more types. The polyamic acid of the present invention can be obtained by using a compound represented by formula (1) as at least one of the tetracarboxylic dianhydrides.

[0068] When the polyamic acid of the present invention is converted into a polyamic acid derivative, a polyimide, the polyimide can be obtained by imidizing the obtained polyamic acid solution together with an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride as a dehydrating agent, and a tertiary amine such as triethylamine, pyridine, or collidine as a dehydration ring-closing catalyst at a temperature of 20 to 150° C. Alternatively, the polyamic acid can be precipitated from the obtained polyamic acid solution using a large amount of a poor solvent (an alcohol-based solvent such as methanol, ethanol, or isopropanol, or a glycol-based solvent), and the precipitated polyamic acid can be imidized in a solvent such as toluene or xylene together with the above-mentioned dehydrating agent and dehydration ring-closing catalyst at a temperature of 20 to 150° C. to obtain a polyimide.

[0069] In the imidization reaction, the ratio of the dehydrating agent to the dehydration ring-closing catalyst is preferably 0.1 to 10 (molar ratio). The total amount of the dehydrating agent and the dehydration ring-closing catalyst used is preferably 1.5 to 10 times the total molar amount of the tetracarboxylic dianhydride used in the synthesis of the polyamic acid. The degree of imidization can be controlled by adjusting the amount of the dehydrating agent and catalyst used in this imidization reaction, the reaction temperature, and the reaction time, and thus a partial polyimide in which only a part of the polyamic acid is imidized can be obtained. The obtained polyimide can be separated from the solvent used in the reaction and redissolved in another solvent to be used as a liquid crystal alignment agent, or it can be used as a liquid crystal alignment agent without being separated from the solvent.

[0070] The polyamic acid ester can be obtained by a synthesis method of reacting a polyamic acid with a hydroxyl group-containing compound, a halide, an epoxy group-containing compound, or the like, or by a synthesis method of reacting a tetracarboxylic acid diester or a tetracarboxylic acid diester dichloride derived from a tetracarboxylic acid dianhydride with a diamine. The tetracarboxylic acid diester derived from a tetracarboxylic acid dianhydride can be obtained, for example, by reacting the tetracarboxylic acid dianhydride with two equivalents of an alcohol to open the ring, and the tetracarboxylic acid diester dichloride can be obtained by reacting the tetracarboxylic acid diester with two equivalents of a chlorinating agent (e.g., thionyl chloride, etc.). The polyamic acid ester may have only an amic acid ester structure, or may be a partial ester in which an amic acid structure and an amic acid ester structure coexist. The polyamic acid ester of the present invention can be obtained by using a tetracarboxylic acid dianhydride represented by formula (1) as at least one of the tetracarboxylic acid dianhydrides.

[0071] The polyamic acid or its derivative of the present invention can be produced in the same manner as known polyamic acids or their derivatives used in the formation of polyimide films. The total amount of tetracarboxylic dianhydrides is preferably 0.9 to 1.1 moles per mole of the total amount of diamines.

[0072] The liquid crystal aligning agent of the present invention may contain only one of these polyamic acids, polyamic acid esters, and polyimides obtained by imidizing these, or may contain two or more of them.

[0073] The molecular weight of the polyamic acid or its derivative of the present invention is, in terms of polystyrene equivalent weight average molecular weight (Mw), preferably 5,000 to 500,000, more preferably 5,000 to 50,000. The molecular weight of the polyamic acid or its derivative can be determined by measurement using gel permeation chromatography (GPC).

[0074] The presence of the polyamic acid or its derivative of the present invention can be confirmed by analyzing the solid content obtained by precipitating the polyamic acid or its derivative with a large amount of poor solvent using IR (infrared spectroscopy) or NMR (nuclear magnetic resonance analysis).The monomer used can also be confirmed by analyzing an extract of the decomposition product of the polyamic acid or its derivative with an aqueous solution of a strong alkali such as KOH or NaOH using an organic solvent using GC (gas chromatography), HPLC (high performance liquid chromatography) or GC-MS (gas chromatography mass spectrometry).

[0075] <Compounds with photoreactive structures> In the present invention, the photoreactive structure refers to a structure that undergoes a photoreaction upon irradiation with ultraviolet light. For example, a photodecomposition structure, a photoisomerization structure, or a photodimerization structure can be suitably used. A liquid crystal alignment agent for photoalignment can be obtained by using a compound having a photoreactive structure as described below as a raw material monomer. Since a photoalignment film generally has a lower VHR reliability than a rubbing alignment film, a greater improvement effect can be obtained by applying the tetracarboxylic dianhydride represented by formula (1) of the present invention to a liquid crystal alignment agent for photoalignment.

[0076] When it is important to improve the liquid crystal alignment, it is preferable to use a compound having a photoisomerization structure. When the coating film of the liquid crystal alignment agent for photoalignment of the present invention using a compound having a photoisomerization structure is irradiated with polarized light for photoalignment as described later, the photoisomerization structure of the polymer main chain that is approximately parallel to the polarization direction selectively undergoes a photoisomerization reaction, and the component that faces a specific direction (approximately perpendicular to the polarization direction) becomes dominant in the polymer chain. In this way, the state in which the component that faces a specific direction becomes dominant in the polymer chain is expressed as the polymer chain being oriented. The fact that the polymer chains are more aligned is expressed as the film having high anisotropy. When the photoalignment film formed by baking this coating film is used in a liquid crystal display element, the interaction between the surface of the oriented film and the liquid crystal molecules results in the liquid crystal molecules being aligned with their major axes aligned in a direction approximately perpendicular to the polarization direction. In this specification, the state in which the polymer chains forming the alignment film are aligned in a specific direction is sometimes expressed as imparting anisotropy. In addition, the fact that polymer chains are aligned in a specific direction is sometimes referred to as having a large anisotropy. Photo-alignment films that utilize photoisomerization reactions have a large anisotropy and are excellent in aligning liquid crystals.

[0077] The tetracarboxylic dianhydrides represented by formula (1) of the present invention have a flexible structure having an alkylene structure. When the coating film of the liquid crystal alignment agent is irradiated with polarized light, the components facing a specific direction become dominant, and in the process of baking this coating film, the polymer main chain is oriented along the components facing a specific direction, thereby amplifying the anisotropy of the film. Since the tetracarboxylic dianhydrides represented by formula (1) have an alkylene structure, which is a flexible structure, the entire polymer is easy to move, and the anisotropy of the liquid crystal alignment film can be increased. In addition, it is considered that the aromatic ring strengthens the interaction with the liquid crystal molecules, thereby further improving the liquid crystal alignment.

[0078] The compound having a photoisomerizable structure includes a tetracarboxylic dianhydride having a photoisomerizable structure or a diamine having a photoisomerizable structure. The compound is preferably at least one selected from the group of compounds having good photosensitivity represented by the following formulas (II) to (VI), and more preferably a compound represented by formula (V). TIFF0007673614000021.tif4684 In formulas (II) to (V), R 2 and R 3 is a monovalent organic group having -NH2 or a monovalent organic group having -CO-O-CO-, and in formula (IV), R 4 is a divalent organic group, and in formula (VI), R 5 is an aromatic ring containing -NH2 or -CO-O-CO-.

[0079] The photoisomerizable structure may be incorporated into either the main chain or the side chain of the polymer in the present invention, but by incorporating it into the main chain, it can be suitably used in an in-plane switching mode liquid crystal display element.

[0080] As the compound having a photoisomerizable structure, at least one selected from the group of compounds represented by the following formulas (II-1), (II-2), (III-1), (III-2), (IV-1), (IV-2), (V-1) to (V-3), (VI-1), and (VI-2) can be suitably used. TIFF0007673614000022.tif132137 TIFF0007673614000023.tif135141 In each of the above formulas, a group that is not fixed to any of the carbon atoms constituting a ring indicates that it can be bonded to any available carbon atom in the ring.

[0081] In formula (V-2), X is an alkylene group having 1 to 12 carbon atoms, and one or more non-adjacent -(CH2)2- in the alkylene group may be replaced with -O- or -NH-. a and Rb R is independently a hydrogen atom, -CH3, -OCH3, -CF3, -F, -COOCH3, or a monovalent group represented by formula (P1-1) or formula (P1-2). c are each independently a hydrogen atom, -CH3, -OCH3, -CF3, -F, or a monovalent group represented by formula (P1-1) or formula (P1-2). j is 0 or 1, and a to c are each independently an integer of 0 to 2. TIFF0007673614000024.tif2364 In formula (P1-1) and formula (P1-2), R d ~R f each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkanoyl group, a substituted or unsubstituted alkoxycarbonyl group, or a substituted or unsubstituted arylcarbonyl group; R d ~R f may be the same or different. * represents the bonding position to the benzene ring in formula (V-2).

[0082] In formula (V-3), ring A and ring B are each independently at least one selected from monocyclic hydrocarbons, condensed polycyclic hydrocarbons, and heterocycles; R 11 is a linear alkylene having 1 to 20 carbon atoms, -COO-, -OCO-, -NHCO-, -CONH-, -N(CH3)CO-, or -CON(CH3)-, and R 12 is a linear alkylene having 1 to 20 carbon atoms, -COO-, -OCO-, -NHCO-, -CONH-, -N(CH3)CO-, or -CON(CH3)-, and R 11 and R 12 In the formula, one or two of -CH2- in the linear alkylene may be replaced by -O-, and R 7 ~R 10 are each independently -F, -CH3, -OCH3, -CF3, or -OH, and b to e are each independently an integer of 0 to 4.

[0083] The compounds represented by the above formula (V-1), formula (V-2), formula (V-3) and formula (VI-2) can be more preferably used from the viewpoint of their orientation, and the compound represented by formula (V-2) is particularly preferred. In the formulas (V-2) and (VI-2), the compound in which the amino group is bonded at the para position can be more preferably used from the viewpoint of their orientation.

[0084] The tetracarboxylic dianhydrides or diamines having a structure capable of isomerizing upon irradiation with ultraviolet light, as shown in formula (II-1), formula (II-2), formula (III-1), formula (III-2), formula (IV-1), formula (IV-2), formula (V-1) to formula (V-3), formula (VI-1), and formula (VI-2), are represented by the formula (II-1-1), formula (II-2-1), formula (II-2-2), formula (II-2-3), formula (II-2-4), formula (II-2-5), formula (II-2-6), formula (II-2-7), formula (II-2-8), formula (II-2-9), formula (II-3-10), formula (II-3-11), formula (II-3-12), formula (II-3-13), formula (II-3-14), formula (II-3-15), formula (II-3-16), formula (II-3-17), formula (II-3-18), formula (II-3-19), formula (II-3-20), formula (II-3-21), formula (II-3-22), formula (II-3-23), formula (II-3-24), formula (II-3-25), formula (II-3-26), formula (II-3-27), formula (II-3-28), formula (II-3-29), formula (II-4-31), formula (II-4-32), formula (II-4-33), formula (II-4-34), formula (II-4-35), formula (II-4-36), formula (II-4-37), formula (II-4-38), formula (II-4-39 ... 2), formula (III-1-1), formula (III-2-1), formula (III-2-2), formula (IV-1-1), formula (IV-2-1), formula (IV-2-2), formula (V-1-1), formula (V-2-1) to formula (V-2-16), formula (V-3-1) to formula (V-3-8), formula (VI-1-1), and formula (VI-2-1) to formula (VI-2-3). TIFF0007673614000025.tif214117 TIFF0007673614000026.tif8994 TIFF0007673614000027.tif7594 TIFF0007673614000028.tif7794 TIFF0007673614000029.tif46140 TIFF0007673614000030.tif99137 TIFF0007673614000031.tif30135 TIFF0007673614000032.tif140138 TIFF0007673614000033.tif8297

[0085] Among these, by using the compounds represented by formula (V-1-1), formula (V-2-1) to formula (V-2-16), and formula (V-3-8), a liquid crystal alignment agent for photo-alignment that is more sensitive to ultraviolet irradiation can be obtained. By using the compounds represented by formula (V-1-1), formula (V-2-1), formula (V-2-4) to formula (V-2-16), and formula (V-3-1) to formula (V-3-8), a liquid crystal alignment agent for photo-alignment that can align liquid crystal molecules more uniformly can be obtained, and it is more preferable to use the compounds represented by formula (V-2-1), formula (V-2-4) to formula (V-2-16). By using the compounds represented by formula (V-2-4) to formula (V-2-16), and formula (V-3-1) to formula (V-3-8), a liquid crystal alignment agent for photo-alignment that can form an alignment film with less coloring can be obtained.

[0086] Preferable examples of the compound having a photodecomposition structure include the following compounds. TIFF0007673614000034.tif125127 The tetracarboxylic dianhydrides represented by the formulae (PA-1) to (PA-3) may be converted into tetracarboxylic diesters or tetracarboxylic diester dichlorides and used as raw materials for polymers.

[0087] In addition, when the compounds represented by formulae (PA-1) to (PA-5) are used as raw material monomers for polymers used in liquid crystal alignment agents that utilize a liquid crystal alignment ability based on a photoisomerization reaction, liquid crystal alignment agents that utilize a liquid crystal alignment ability based on photodimerization, or liquid crystal alignment agents for rubbing, they are treated as tetracarboxylic dianhydrides that do not have a photoreactive structure or diamines that do not have a photoreactive structure.

[0088] Preferable examples of the compound having a photodimerization structure include the following compounds. TIFF0007673614000035.tif87143 In formula (PDI-12), R 12is an alkyl group or alkoxy group having 1 to 10 carbon atoms, and at least one hydrogen of the alkyl group or alkoxy group may be replaced by fluorine.

[0089] Among these, the diamines represented by the formulae (PDI-9) and (PDI-11) can be more preferably used.

[0090] In an embodiment in which a (non-photosensitive) tetracarboxylic dianhydride having no photoreactive structure and a (photosensitive) tetracarboxylic dianhydride having a photoreactive structure are used in combination, the photosensitive tetracarboxylic dianhydride is preferably 30 to 100 mol %, particularly preferably 50 to 100 mol %, based on the total amount of tetracarboxylic dianhydride used as a raw material in producing the polyamic acid or its derivative of the present invention, in order to prevent a decrease in the sensitivity of the liquid crystal alignment film to light. In addition, two or more photosensitive tetracarboxylic dianhydrides may be used in combination in order to improve the various characteristics described above, such as sensitivity to light, electrical characteristics, and afterimage characteristics.

[0091] In an embodiment in which a diamine having no photoreactive structure (non-photosensitive) and a diamine having a photoreactive structure (photosensitive) are used in combination, the photosensitive diamine is preferably 20 to 100 mol %, particularly preferably 50 to 100 mol %, of the total amount of diamine used as a raw material in producing the polyamic acid or its derivative of the present invention in order to prevent a decrease in the sensitivity of the alignment film to light. In addition, two or more photosensitive diamines may be used in combination in order to improve the various characteristics described above, such as sensitivity to light and residual image characteristics. As described above, the embodiment of the present invention includes a case in which the total amount of tetracarboxylic dianhydride is occupied by non-photosensitive tetracarboxylic dianhydride, but even in that case, it is required that at least 20 mol % of the total amount of diamine is a diamine having a photoreactive structure.

[0092] In order to improve the various characteristics described above, such as sensitivity to light and afterimage characteristics, a photosensitive tetracarboxylic acid dianhydride and a photosensitive diamine may be used in combination, or two or more of each may be used in combination.

[0093] <Other tetracarboxylic dianhydrides> The tetracarboxylic dianhydrides other than the tetracarboxylic dianhydrides represented by formula (1) and the compounds having a photoreactive structure described above used as raw materials for the polymer of the present invention can be selected from known tetracarboxylic dianhydrides without any limitations.

[0094] Examples of tetracarboxylic dianhydrides are shown below. These tetracarboxylic dianhydrides may be converted into tetracarboxylic diesters or tetracarboxylic diester dichlorides and used as raw materials for polymers.

[0095] Such tetracarboxylic dianhydrides may belong to either an aromatic group (including a heteroaromatic ring system) in which a dicarboxylic anhydride is directly bonded to an aromatic ring, or an aliphatic group (including a heterocyclic ring system) in which a dicarboxylic anhydride is not directly bonded to an aromatic ring.

[0096] Examples of such tetracarboxylic dianhydrides include the compounds represented by the following formulae (AN-1), (AN-3) to (AN-9), (AN-11), (AN-12), (AN-15), (AN-10-1), (AN-10-2), and (AN-16-1) to (AN-16-17).

[0097] [Tetracarboxylic acid dianhydride represented by formula (AN-1)] TIFF0007673614000036.tif3595 In formula (AN-1), G 11 X is a single bond, an alkylene group having 1 to 12 carbon atoms, a 1,4-phenylene group, or a 1,4-cyclohexylene group. 11 are independently a single bond or -CH2-. 12 are independently any of the following trivalent groups: TIFF0007673614000037.tif1851 G 12When is >CH-, the hydrogen atom of >CH- may be substituted with a methyl group. 12 When is >N-, G 11 is not a single bond or -CH2-, and X 11 R cannot be a single bond. 11 is a hydrogen atom or a methyl group.

[0098] Examples of the tetracarboxylic dianhydride represented by formula (AN-1) include the compounds represented by the following formulae (AN-1-1) to (AN-1-15). TIFF0007673614000038.tif140140 In formulas (AN-1-2) and (AN-1-14), each m is independently an integer of 1 to 12.

[0099] [Tetracarboxylic acid dianhydride represented by formula (AN-3)] TIFF0007673614000039.tif2874 In formula (AN-3), ring A 11 is a cyclohexane ring or a benzene ring.

[0100] Examples of the tetracarboxylic dianhydride represented by formula (AN-3) include the compounds represented by the following formulae (AN-3-1) and (AN-3-2). TIFF0007673614000040.tif2877

[0101] [Tetracarboxylic acid dianhydride represented by formula (AN-4)] TIFF0007673614000041.tif2882 In formula (AN-4), G 13 is a single bond, -(CH2) m -, -O-, -S-, -C(CH3)2-, -SO2-, -CO-, -C(CF3)2-, or a divalent group represented by the following formula (G13-1), where m is an integer of 1 to 12. 11are each independently a cyclohexane ring or a benzene ring. 13 is ring A 11 It can bond to any of the available carbons. TIFF0007673614000042.tif2497 In formula (G13-1), G 13a and G 13b are each independently a single bond, or a divalent group represented by -O-, -CONH-, or -NHCO-. The phenylene group is preferably a 1,4-phenylene group or a 1,3-phenylene group.

[0102] Examples of the tetracarboxylic dianhydride represented by formula (AN-4) include the compounds represented by the following formulae (AN-4-1) to (AN-4-31). TIFF0007673614000043.tif111143 TIFF0007673614000044.tif143138 In formula (AN-4-17), m is an integer from 1 to 12.

[0103] TIFF0007673614000045.tif61125 TIFF0007673614000046.tif64158

[0104] [Tetracarboxylic acid dianhydride represented by formula (AN-5)] TIFF0007673614000047.tif4174 In formula (AN-5), R 11 are independently a hydrogen atom or a methyl group. 11 Among them, R in the benzene ring 11 is attached to any of the substitutable positions of the benzene ring.

[0105] Examples of the tetracarboxylic dianhydride represented by formula (AN-5) include the compounds represented by the following formulae (AN-5-1) to (AN-5-3). TIFF0007673614000048.tif50136

[0106] [Tetracarboxylic acid dianhydride represented by formula (AN-6)] TIFF0007673614000049.tif30102 In formula (AN-6), X 11 are independently a single bond or -CH2-. 12 is -CH2-, -CH2CH2- or -CH=CH-. n is 1 or 2. When n is 2, two X 12 may be the same or different from each other.

[0107] Examples of the tetracarboxylic dianhydride represented by formula (AN-6) include the compounds represented by the following formulae (AN-6-1) to (AN-6-12). TIFF0007673614000050.tif115132

[0108] [Tetracarboxylic dianhydride represented by formula (AN-7)] TIFF0007673614000051.tif3584 In formula (AN-7), X 11 is a single bond or -CH2-.

[0109] Examples of the tetracarboxylic dianhydride represented by formula (AN-7) include the compounds represented by the following formulae (AN-7-1) and (AN-7-2). TIFF0007673614000052.tif3987

[0110] [Tetracarboxylic dianhydride represented by formula (AN-8)] TIFF0007673614000053.tif4687 In formula (AN-8), X 11 is a single bond or -CH2-. 12 is a hydrogen atom, a methyl group, an ethyl group, or a phenyl group. 12 is a cyclohexane ring or a cyclohexene ring.

[0111] Examples of the tetracarboxylic dianhydride represented by formula (AN-8) include the compounds represented by the following formulae (AN-8-1) and (AN-8-2). TIFF0007673614000054.tif5387

[0112] [Tetracarboxylic acid dianhydride represented by formula (AN-9)] TIFF0007673614000055.tif3788 In formula (AN-9), each r is independently 0 or 1.

[0113] Examples of the tetracarboxylic dianhydride represented by formula (AN-9) include the compounds represented by the following formulae (AN-9-1) to (AN-9-3). TIFF0007673614000056.tif37157

[0114] [Tetracarboxylic acid dianhydrides represented by formula (AN-10-1) and formula (AN-10-2)] TIFF0007673614000057.tif3986

[0115] [Tetracarboxylic dianhydride represented by formula (AN-11)] TIFF0007673614000058.tif3285 In formula (AN-11), ring A 11 are independently a cyclohexane ring or a benzene ring.

[0116] Examples of the tetracarboxylic dianhydride represented by formula (AN-11) include the compounds represented by the following formulae (AN-11-1) to (AN-11-3). TIFF0007673614000059.tif31147

[0117] [Tetracarboxylic dianhydride represented by formula (AN-12)] TIFF0007673614000060.tif4091 In formula (AN-12), ring A 11 are each independently a cyclohexane ring or a benzene ring.

[0118] Examples of the tetracarboxylic dianhydride represented by formula (AN-12) include the compounds represented by the following formulae (AN-12-1) to (AN-12-3). TIFF0007673614000061.tif41157

[0119] [Tetracarboxylic dianhydride represented by formula (AN-15)] TIFF0007673614000062.tif3098 In formula (AN-15), w is an integer of 1 to 10.

[0120] Examples of the tetracarboxylic dianhydride represented by formula (AN-15) include the compounds represented by the following formulae (AN-15-1) to (AN-15-3). TIFF0007673614000063.tif28146

[0121] Other tetracarboxylic dianhydrides include the compounds represented by the following formulae (AN-16-1) to (AN-16-17). TIFF0007673614000064.tif188138

[0122] Among the above tetracarboxylic dianhydrides, preferred materials for improving the properties of the liquid crystal alignment film are described below. When emphasis is placed on further improving the liquid crystal alignment, compounds represented by formula (AN-1-2), formula (AN-4-17), formula (AN-4-21), formula (AN-4-29) or formula (AN-16-17) are more preferred, and in formula (AN-1-2), m is preferably 4 to 8, and in formula (AN-4-17), m is preferably 4 to 8.

[0123] When emphasis is placed on improving the transmittance of a liquid crystal display element, the compounds represented by formula (AN-1-1), (AN-1-2), (AN-2-1), (AN-3-1), (AN-4-17), (AN-4-30), (AN-5-1), (AN-7-2), (AN-10-1), (AN-16-3) or (AN-16-4) are preferred, and in formula (AN-1-2), m is preferably 4 or 8, and in formula (AN-4-17), m is preferably 4 to 8, and more preferably m is 8.

[0124] When emphasis is placed on improving the VHR of a liquid crystal display element, the compounds represented by formula (AN-1-1), (AN-1-2), (AN-3-1), (AN-4-17), (AN-4-30), (AN-7-2), (AN-10-1), (AN-16-3), (AN-16-4) or (AN-2-1) are preferred, and in formula (AN-1-2), m is preferably 4 or 8, and in formula (AN-4-17), m is preferably 4 or 8, and more preferably m is 8.

[0125] One effective method for preventing image sticking is to improve the relaxation speed of the residual charge (residual DC) in the liquid crystal alignment film by reducing the volume resistance of the liquid crystal alignment film. When this purpose is important, the compounds represented by formula (AN-1-13), formula (AN-3-2), formula (AN-4-21), formula (AN-4-29), or formula (AN-11-3) are preferred.

[0126] [Amount of tetracarboxylic dianhydride represented by formula (1) in raw materials] In the raw material composition used as a raw material for the polymer of the present invention, the tetracarboxylic dianhydride represented by formula (1) is preferably 10 to 100 mol %, more preferably 10 to 60 mol %, and even more preferably 20 to 60 mol %, based on the total amount of tetracarboxylic dianhydrides used as raw materials.

[0127] <Other diamines> Diamines other than the compound having a photoreactive structure, which are used as raw materials for the polymer of the present invention, can be selected from known diamines without any limitation.

[0128] Diamines can be divided into two types based on their structure. That is, when the skeleton connecting the two amino groups is viewed as the main chain, there are diamines that have groups branching from the main chain, i.e., side chain groups, and diamines that do not have side chain groups. In the following explanation, diamines that have such side chain groups may be referred to as side chain type diamines. And diamines that do not have such side chain groups may be referred to as non-side chain type diamines. The side chain groups are groups that have the effect of increasing the pretilt angle. By appropriately using the non-side chain type diamine and the side chain type diamine, it is possible to meet the pretilt angle required for each.

[0129] It is preferable to use the side chain diamines in combination to the extent that the characteristics of the present invention are not impaired. It is also preferable to selectively use the side chain diamines and the non-side chain diamines for the purpose of improving characteristics such as vertical alignment property for liquid crystal, VHR, and afterimage characteristics.

[0130] Known diamines having no side chains are shown in the following formulas (DI-1) to (DI-16). TIFF0007673614000065.tif126136 In the above formula (DI-1), G 20is -CH2- or a group represented by formula (DI-1-a). 20 is -CH2-, at least one of the m -CH2- may be replaced with -NH- or -O-, and at least one hydrogen atom of the m -CH2- may be replaced with a hydroxyl group or a methyl group. m is an integer of 1 to 12. When m in DI-1 is 2 or more, multiple G 20 may be the same or different, provided that G 20 When the formula is (DI-1-a), m is 1. TIFF0007673614000066.tif2747 In formula (DI-1-a), each v is independently an integer of 1 to 6.

[0131] In formula (DI-3), formula (DI-6) and formula (DI-7), G 21 are independently a single bond, -NH-, -NCH3-, -O-, -S-, -SS-, -SO2-, -CO-, -COO-, -CONCH3-, -CONH-, -C(CH3)2-, -C(CF3)2-, -(CH2) m -, -O-(CH2) m -O-, -N(CH3)-(CH2) k -N(CH3)-, -(O-C2H4) m -O-, -O-CH2-C(CF3)2-CH2-O-, -O-CO-(CH2) m -CO-O-, -CO-O-(CH2) m -O-CO-, -(CH2) m -NH-(CH2) m -, -CO-(CH2) k -NH-(CH2) k -, -(NH-(CH2) m ) k -NH-, -CO-C3H6-(NH-C3H6) n -CO- or -S-(CH2) m -S-, m is independently an integer of 1 to 12, k is an integer of 1 to 5, and n is 1 or 2. In formula (DI-4), s is independently an integer of 0 to 2.

[0132] In formula (DI-5), G 33 is a single bond, -NH-, -NCH3-, -O-, -S-, -SS-, -SO2-, -CO-, -COO-, -CONCH3-, -CONH-, -C(CH3)2-, -C(CF3)2-, -(CH2) m -, -O-(CH2) m -O-, -N(CH3)-(CH2) k -N(CH3)-, -(O-C2H4) m -O-, -O-CH2-C(CF3)2-CH2-O-, -O-CO-(CH2) m -CO-O-, -CO-O-(CH2) m -O-CO-, -(CH2) m -NH-(CH2) m -, -CO-(CH2) k -NH-(CH2) k -, -(NH-(CH2) m ) k -NH-, -CO-C3H6-(NH-C3H6) n -CO- or -S-(CH2) m -S-, -N(Boc)-(CH2) e -N(Boc)-, -NH-(CH2) e -N(Boc)-, -N(Boc)-(CH2) e -, -(CH2) m -N(Boc)-CONH-(CH2) m -, -(CH2) m -N(Boc)-(CH2) m -, a group represented by the following formula (DI-5-a) or the following formula (DI-5-b), m is independently an integer of 1 to 12, k is an integer of 1 to 5, e is an integer of 2 to 10, and n is 1 or 2. Boc is a t-butoxycarbonyl group.

[0133] In formula (DI-6) and formula (DI-7), G 22 are independently a single bond, -O-, -S-, -CO-, -C(CH3)2-, -C(CF3)2-, or an alkylene group having 1 to 10 carbon atoms.

[0134] At least one hydrogen atom of the cyclohexane ring and the benzene ring in the formulae (DI-2) to (DI-7) may be substituted with -F, -Cl, an alkylene group having 1 to 3 carbon atoms, -OCH3, -OH, -CF3, -CO2H, -CONH2, -NHC6H5, a phenyl group, or a benzyl group. In addition, in the formula (DI-4), at least one hydrogen atom of the cyclohexane ring and the benzene ring may be substituted with one selected from the group of groups represented by any of the following formulae (DI-4-a) to (DI-4-i). In the formula (DI-5), G 33 When is a single bond, at least one hydrogen atom of the cyclohexane ring and the benzene ring may be substituted with NHBoc or N(Boc)2.

[0135] A group that is not fixed to a carbon atom that constitutes a ring indicates that it can be bonded to any available carbon in the ring. And the bonding position of -NH2 to the cyclohexane ring or benzene ring is G 21 , G 22 or G 33 are possible binding positions excluding the binding position of TIFF0007673614000067.tif38140 TIFF0007673614000068.tif43155 In formula (DI-4-a) and formula (DI-4-b), R 20 are independently a hydrogen atom or -CH3. In formula (DI-4-f) and formula (DI-4-g), m is each independently an integer of 0 to 12, and Boc is a t-butoxycarbonyl group.

[0136] TIFF0007673614000069.tif3897 In formula (DI-5-a), each q is independently an integer of 0 to 6. 44 is a hydrogen atom, -OH, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0137] TIFF0007673614000070.tif84130 In formula (DI-11), r is 0 or 1. In formulas (DI-8) to (DI-11), -NH2 bonded to a ring can be bonded to any of the available carbons in the ring.

[0138] TIFF0007673614000071.tif127132 In formula (DI-12), R 21 and R 22 are each independently an alkyl group having 1 to 3 carbon atoms or a phenyl group, G 23 each independently represents an alkylene group having 1 to 6 carbon atoms, a phenylene group, or a phenylene group substituted with an alkyl group; and w is an integer of 1 to 10. In formula (DI-13), R 23 each independently represents an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or -Cl; p each independently represents an integer of 0 to 3; and q each independently represents an integer of 0 to 4. In formula (DI-14), ring B is a monocyclic heteroaromatic group, and R 24 is a hydrogen atom, -F, -Cl, an alkyl group, an alkoxy group, an alkenyl group, or an alkynyl group having 1 to 6 carbon atoms, and q is independently an integer of 0 to 4. When q is 2 or more, multiple R 24 may be the same or different. In formula (DI-15), ring C is a heterocyclic aromatic group or a heterocyclic aliphatic group. In formula (DI-16), G 24 is a single bond, an alkylene group having 2 to 6 carbon atoms, or a 1,4-phenylene group, and r is 0 or 1. A group that is not fixed to a carbon atom constituting a ring can be bonded to any available carbon atom in the ring. In formulae (DI-13) to (DI-16), -NH2 bonded to a ring can be bonded to any available carbon atom in the ring.

[0139] Examples of the diamine represented by formula (DI-1) are shown in the following formulas (DI-1-1) to (DI-1-9). TIFF0007673614000072.tif100153 In formula (DI-1-7) and formula (DI-1-8), k is independently an integer of 1 to 3. In formula (DI-1-9), v is independently an integer of 1 to 6.

[0140] Examples of diamines represented by formulae (DI-2) to (DI-3) are shown in the following formulae (DI-2-1), (DI-2-2), and (DI-3-1) to (DI-3-3). TIFF0007673614000073.tif55152

[0141] Examples of the diamine represented by formula (DI-4) are shown in the following formulas (DI-4-1) to (DI-4-27). TIFF0007673614000074.tif67136 TIFF0007673614000075.tif65141 TIFF0007673614000076.tif46141 TIFF0007673614000077.tif48146 TIFF0007673614000078.tif3096 TIFF0007673614000079.tif41160 TIFF0007673614000080.tif84153In formulas (DI-4-20) and (DI-4-21), each m is independently an integer of 1 to 12.

[0142] Examples of the diamine represented by formula (DI-5) are shown in the following formulas (DI-5-1) to (DI-5-50). TIFF0007673614000081.tif77150 In formula (DI-5-1), m is an integer of 1 to 12.

[0143] TIFF0007673614000082.tif66127 In formula (DI-5-12) and formula (DI-5-13), each m is independently an integer of 1 to 12.

[0144] TIFF0007673614000083.tif94132 In formula (DI-5-16), v is an integer of 1 to 6.

[0145] TIFF0007673614000084.tif97155 In formula (DI-5-30), k is an integer of 1 to 5.

[0146] TIFF0007673614000085.tif130143 In Formulas (DI-5-35) to (DI-5-37) and (DI-5-39), m is each independently an integer of 1 to 12; in Formulas (DI-5-38) and (DI-5-39), k is each independently an integer of 1 to 5; and in Formula (DI-5-40), n is an integer of 1 or 2.

[0147] TIFF0007673614000086.tif54138 In formulas (DI-5-42) to (DI-5-44), e is independently an integer of 2 to 10, and in formula (DI-5-45), R 43 is a hydrogen atom, -NHBoc, or -N(Boc)2. In Formulae (DI-5-42) to (DI-5-44), Boc is a t-butoxycarbonyl group.

[0148] TIFF0007673614000087.tif44112 TIFF0007673614000088.tif2672 TIFF0007673614000089.tif35150

[0149] Examples of the diamine represented by formula (DI-6) are shown in the following formulas (DI-6-1) to (DI-6-7). TIFF0007673614000090.tif86150

[0150] Examples of the diamine represented by formula (DI-7) are shown in the following formulas (DI-7-1) to (DI-7-11). TIFF0007673614000091.tif109118 In formula (DI-7-3) and formula (DI-7-4), m is each independently an integer of 1 to 12, and n is independently 1 or 2.

[0151] TIFF0007673614000092.tif11184 TIFF0007673614000093.tif3979

[0152] Examples of the diamine represented by formula (DI-8) are shown in the following formulas (DI-8-1) to (DI-8-4). TIFF0007673614000094.tif31140

[0153] Examples of the diamine represented by formula (DI-9) are shown in the following formulas (DI-9-1) to (DI-9-3). TIFF0007673614000095.tif34143

[0154] Examples of diamines represented by formula (DI-10) are shown in the following formulas (DI-10-1) and (DI-10-2). TIFF0007673614000096.tif3189

[0155] Examples of the diamine represented by formula (DI-11) are shown in the following formulas (DI-11-1) to (DI-11-3). TIFF0007673614000097.tif23140

[0156] An example of the diamine represented by formula (DI-12) is shown in the following formula (DI-12-1). TIFF0007673614000098.tif2866

[0157] Examples of diamines represented by formula (DI-13) are shown in the following formulas (DI-13-1) to (DI-13-13). TIFF0007673614000099.tif23130 TIFF0007673614000100.tif66132 TIFF0007673614000101.tif66130

[0158] Examples of diamines represented by formula (DI-14) are shown in the following formulas (DI-14-1) to (DI-14-9). TIFF0007673614000102.tif74117

[0159] Examples of diamines represented by formula (DI-15) are shown in the following formulas (DI-15-1) to (DI-5-12). TIFF0007673614000103.tif64150 TIFF0007673614000104.tif61153

[0160] An example of the diamine represented by formula (DI-16) is shown in the following formula (DI-16-1). TIFF0007673614000105.tif2659

[0161] Next, the dihydrazide used as the raw material for the polymer of the present invention will be described. Known dihydrazides having no side chains include compounds represented by any of the following formulas (DIH-1) to (DIH-3). TIFF0007673614000106.tif56102 In formula (DIH-1), G 25 is a single bond, an alkylene group having 1 to 20 carbon atoms, -CO-, -O-, -S-, -SO2-, -C(CH3)2-, or -C(CF3)2-. In formula (DIH-2), ring D is a cyclohexane ring, a benzene ring, or a naphthalene ring, and at least one hydrogen atom of this group may be substituted with a methyl group, an ethyl group, or a phenyl group. In formula (DIH-3), ring E is each independently a cyclohexane ring or a benzene ring, and at least one hydrogen atom of this group may be substituted with a methyl group, an ethyl group, or a phenyl group. The multiple rings E may be the same or different from each other. Y is a single bond, an alkylene group having 1 to 20 carbon atoms, -CO-, -O-, -S-, -SO2-, -C(CH3)2-, or -C(CF3)2-. In formula (DIH-2) and formula (DIH-3), -CONHNH2 bonded to a ring can be bonded to any available carbon in the ring.

[0162] Examples of the compounds represented by any one of formulas (DIH-1) to (DIH-3) are shown in the following formulas (DIH-1-1), (DIH-1-2), (DIH-2-1) to (DIH-2-3), and (DIH-3-1) to (DIH-3-6). TIFF0007673614000107.tif2689 In formula (DIH-1-2), m is an integer of 1 to 12.

[0163] TIFF0007673614000108.tif31148 TIFF0007673614000109.tif84137

[0164] Diamines suitable for increasing the pretilt angle will be described. The compound of the present invention can be suitably used as a liquid crystal aligning agent for use in a horizontal electric field type liquid crystal display element, but it is also possible to increase the pretilt angle by using it in combination with the following diamines. Diamines having a side chain group suitable for increasing the pretilt angle include diamines represented by any of formulas (DI-31) to (DI-35) and formulas (DI-36-1) to (DI-36-8). TIFF0007673614000110.tif3679

[0165] In formula (DI-31), G 26 is a single bond, -O-, -COO-, -OCO-, -CO-, -CONH-, -CH2O-, -OCH2-, -CF2O-, -OCF2-, or -(CH2) ma -, and ma is an integer from 1 to 12. 26 Preferred examples of R are a single bond, -O-, -COO-, -OCO-, -CH2O-, and an alkylene group having 1 to 3 carbon atoms, and particularly preferred examples are a single bond, -O-, -COO-, -OCO-, -CH2O-, -CH2-, and -CH2CH2-. 25 is an alkyl group having 3 to 30 carbon atoms, a phenyl group, a group having a steroid skeleton, or a group represented by the following formula (DI-31-a). In this alkyl group, at least one hydrogen atom may be replaced by -F, and at least one -CH2- may be replaced by -O-, -CH=CH- or -C≡C-. The hydrogen atom of this phenyl group may be replaced by -F, -CH3, -OCH3, -OCH2F, -OCHF 2、 -OCF 3、 The benzene ring may be substituted with an alkyl group having 3 to 30 carbon atoms or an alkoxy group having 3 to 30 carbon atoms. -NH2 bonded to the benzene ring can be bonded to any of the available carbon atoms of the benzene ring, but the bonding position is preferably the meta position or the para position. 25 -G 26 When the bonding position of "-" is regarded as the 1st position, the two bonding positions are preferably the 3rd and 5th positions, or the 2nd and 5th positions.

[0166] TIFF0007673614000111.tif16161 In formula (DI-31-a), G 27 , G 28 and G 29 are bonding groups, each of which is independently a single bond or an alkylene group having 1 to 12 carbon atoms, and one or more -CH2- in the alkylene group may be replaced by -O-, -COO-, -OCO-, -CONH-, or -CH=CH-. 21 , ring B 22 , ring B 23 and ring B 24 are each independently a 1,4-phenylene group, a 1,4-cyclohexylene group, a 1,3-dioxane-2,5-diyl group, a pyrimidine-2,5-diyl group, a pyridine-2,5-diyl group, a naphthalene-1,5-diyl group, a naphthalene-2,7-diyl group, or an anthracene-9,10-diyl group; 21 , ring B 22 , ring B 23 and ring B 24 In the formula, at least one hydrogen atom may be replaced with -F or -CH3, s, t, and u are each independently an integer of 0 to 2, the sum of which is 1 to 5, and when s, t, or u is 2, the two bonding groups in each parentheses may be the same or different, and the two rings may be the same or different. 26 is a hydrogen atom, -F, -OH, an alkyl group having 1 to 30 carbon atoms, a fluorine-substituted alkyl group having 1 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, -CN, -OCH2F, -OCHF2, or -OCF3, and at least one -CH2- in the alkyl group having 1 to 30 carbon atoms or the alkoxy group having 1 to 30 carbon atoms may be replaced by a divalent group represented by the following formula (DI-31-b). TIFF0007673614000112.tif2599 In formula (DI-31-b), R 27 and R 28each independently represents an alkyl group having 1 to 3 carbon atoms, and v is an integer of 1 to 6.

[0167] TIFF0007673614000113.tif87114 In formula (DI-32) and formula (DI-33), G 30 are independently a single bond, -CO- or -CH2-; R 29 are independently a hydrogen atom or -CH3, and R 30 are independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkenyl group having 2 to 20 carbon atoms. At least one hydrogen atom of the benzene ring in formula (DI-33) may be substituted with an alkyl group having 1 to 20 carbon atoms or a phenyl group. In addition, it indicates that a group that is not fixedly bonded to any of the carbon atoms constituting the ring can be bonded to any of the available carbon atoms in the ring. The two groups "-phenylene-G" in formula (DI-32) 30 It is preferred that one of the -O- groups is bonded to the 3-position of the steroid nucleus, and the other is bonded to the 6-position of the steroid nucleus. 30 The bonding position of -O-" to the benzene ring is preferably meta or para relative to the bonding position of the steroid nucleus. In formula (DI-32) and formula (DI-33), -NH2 bonded to the benzene ring can be bonded to any of the available carbons in the ring.

[0168] TIFF0007673614000114.tif77115 In formula (DI-34) and formula (DI-35), G 31 are independently -O- or an alkylene group having 1 to 6 carbon atoms; G 32 R is a single bond or an alkylene group having 1 to 3 carbon atoms. 31 R is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and at least one -CH2- in this alkyl group may be replaced by -O-, -CH=CH- or -C≡C-. 32 is an alkyl group having 6 to 22 carbon atoms, and R33 is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms. 25 is a 1,4-phenylene group or a 1,4-cyclohexylene group, and r is 0 or 1. And -NH2 attached to the benzene ring can be attached to any of the available carbons of the benzene ring, but independently G 31 It is preferably in the meta or para position relative to the bonding position of

[0169] Examples of the compound represented by formula (DI-31) are shown in the following formulae (DI-31-1) to (DI-31-55). TIFF0007673614000115.tif163143

[0170] In formulas (DI-31-1) to (DI-31-11), R 34 R are each independently an alkyl group having 1 to 30 carbon atoms or an alkoxy group having 1 to 30 carbon atoms, and preferably an alkyl group having 5 to 25 carbon atoms or an alkoxy group having 5 to 25 carbon atoms. 35 each independently represents an alkyl group having 1 to 30 carbon atoms or an alkoxy group having 1 to 30 carbon atoms, and preferably an alkyl group having 3 to 25 carbon atoms or an alkoxy group having 3 to 25 carbon atoms. TIFF0007673614000116.tif77119

[0171] In formulas (DI-31-12) to (DI-31-17), R 36 R is independently an alkyl group having 4 to 30 carbon atoms, and preferably an alkyl group having 6 to 25 carbon atoms. 37 are each independently an alkyl group having 6 to 30 carbon atoms, and preferably an alkyl group having 8 to 25 carbon atoms. TIFF0007673614000117.tif76134 TIFF0007673614000118.tif84143 TIFF0007673614000119.tif77148 TIFF0007673614000120.tif54122 TIFF0007673614000121.tif107140

[0172] In formulas (DI-31-18) to (DI-31-43), R 38 R are each independently an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms, and preferably an alkyl group having 3 to 20 carbon atoms or an alkoxy group having 3 to 20 carbon atoms. 39 are each independently a hydrogen atom, -F, an alkyl group having 1 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, -CN, -OCH2F, -OCHF2 or -OCF3, and preferably an alkyl group having 3 to 25 carbon atoms or an alkoxy group having 3 to 25 carbon atoms. And G 33 is an alkylene group having 1 to 20 carbon atoms.

[0173] TIFF0007673614000122.tif54150 TIFF0007673614000123.tif107150 TIFF0007673614000124.tif50134 TIFF0007673614000125.tif81131

[0174] Examples of the compound represented by formula (DI-32) are shown in the following formulas (DI-32-1) to (DI-32-4). TIFF0007673614000126.tif132150

[0175] Examples of the compound represented by formula (DI-33) are shown in the following formulas (DI-33-1) to (DI-33-8). TIFF0007673614000127.tif97150 TIFF0007673614000128.tif101149

[0176] Examples of the compound represented by formula (DI-34) are shown in the following formulas (DI-34-1) to (DI-34-12). TIFF0007673614000129.tif94148 TIFF0007673614000130.tif97148 TIFF0007673614000131.tif69148 TIFF0007673614000132.tif99148 In formulas (DI-34-1) to (DI-34-12), R 40 are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R 41 each independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.

[0177] Examples of the compound represented by formula (DI-35) are shown in the following formulae (DI-35-1) to (DI-35-3). TIFF0007673614000133.tif66125 In formulas (DI-35-1) to (DI-35-3), R 37 are each independently an alkyl group having 6 to 30 carbon atoms, and R 41 each independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.

[0178] The compounds represented by formulae (DI-36-1) to (DI-36-8) are shown below. TIFF0007673614000134.tif130153 In formulas (DI-36-1) to (DI-36-8), R 42 are each independently an alkyl group having 3 to 30 carbon atoms.

[0179] Among the above diamines, preferred materials for improving the properties of the liquid crystal alignment film described below will be described. When emphasis is placed on improving the liquid crystal alignment, it is preferable to use a compound represented by formula (DI-1-3), formula (DI-5-1), formula (DI-5-5), formula (DI-5-9), formula (DI-5-12), formula (DI-5-13), formula (DI-5-29), formula (DI-6-7), formula (DI-7-3), or formula (DI-11-2). In formula (DI-5-1), m is preferably 2 to 8, more preferably m is 4 to 8. In formula (DI-5-12), m is preferably 2 to 6, more preferably m is 5. In formula (DI-5-13), m is preferably 1 or 2, more preferably m is 1.

[0180] When emphasis is placed on improving the transmittance, it is preferable to use a diamine represented by formula (DI-1-3), formula (DI-2-1), formula (DI-5-1), formula (DI-5-5), formula (DI-5-24), or formula (DI-7-3), and more preferably a compound represented by formula (DI-2-1). In formula (DI-5-1), m is preferably 2 to 8, and more preferably m is 8. In formula (DI-7-3), m is preferably 2 or 3, n is preferably 1 or 2, and more preferably m is 3, n is preferably 1.

[0181] When it is important to improve the VHR of the liquid crystal display element, it is preferable to use a compound represented by formula (DI-2-1), formula (DI-4-1), formula (DI-4-2), formula (DI-4-10), formula (DI-4-15), formula (DI-4-22), formula (DI-5-1), formula (DI-5-28), formula (DI-5-30), or formula (DI-13-1), and more preferable is a diamine represented by formula (DI-2-1), formula (DI-5-1), or formula (DI-13-1). In formula (DI-5-1), m=1 is preferable. In formula (DI-5-30), k=2 is preferable.

[0182] One of the effective methods for preventing image sticking is to improve the relaxation speed of the residual charge (residual DC) in the liquid crystal alignment film by reducing the volume resistance of the liquid crystal alignment film. When this purpose is important, it is preferable to use a compound represented by formula (DI-4-1), formula (DI-4-2), formula (DI-4-10), formula (DI-4-15), formula (DI-5-1), formula (DI-5-12), formula (DI-5-13), formula (DI-5-28), formula (DI-4-20), formula (DI-4-21), or formula (DI-16-1), and more preferable to use a compound represented by formula (DI-4-1), formula (DI-5-1), or formula (DI-5-13). In formula (DI-5-1), m=2 to 8 is preferable, and m=4 to 8 is more preferable. In formula (DI-5-12), m=2 to 6 is preferable, and m=5 is more preferable. In formula (DI-5-13), m=1 or 2 is preferable, and m=1 is more preferable.

[0183] In the raw material composition used as the raw material of the polymer of the present invention, a part of the diamines may be replaced with at least one selected from the group consisting of monoamines and monohydrazides. The ratio of the at least one selected from the group consisting of monoamines and monohydrazides to the diamines is preferably in the range of 40 mol% or less. Such a replacement can cause the termination of the polymerization reaction when producing polyamic acid, and can suppress the further progress of the polymerization reaction. For this reason, such a replacement can easily control the molecular weight of the resulting polymer (polyamic acid or its derivative), and can improve the coating properties of the liquid crystal alignment agent, for example, without impairing the effects of the present invention. The diamines that may be replaced with monoamines or monohydrazides may be one type or two or more types, as long as the effects of the present invention are not impaired. Examples of the monoamine include aniline, 4-hydroxyaniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, para-aminophenyltrimethoxysilane, and 3-aminopropyltriethoxysilane.

[0184] When the polymer of the present invention is a polyamic acid or its derivative, the raw material may further contain a monoisocyanate compound as a monomer. By including a monoisocyanate compound in the monomer, the terminal of the obtained polyamic acid or its derivative is modified, and the molecular weight is adjusted. By using this terminal-modified polyamic acid or its derivative, for example, the coating properties of the liquid crystal alignment agent can be improved without impairing the effect of the present invention. From the above viewpoint, it is preferable that the content of the monoisocyanate compound in the monomer is 1 to 10 mol% with respect to the total amount of the diamine and tetracarboxylic dianhydride in the monomer. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

[0185] <Liquid crystal alignment agent> The liquid crystal alignment agent made of the polymer of the present invention will be described in detail below. The liquid crystal alignment agent of the present invention may be composed of one type of the polymer of the present invention, or may be a mixture of the polymer of the present invention and a polymer other than the present invention. In this specification, a liquid crystal alignment agent composed of one type of the above-mentioned polymer may be referred to as a single-layer type liquid crystal alignment agent. A liquid crystal alignment agent made by mixing two or more types of the above-mentioned polymers may be referred to as a blend type liquid crystal alignment agent. A blend type liquid crystal alignment agent is used particularly when VHR reliability and other electrical properties are important.

[0186] As the polymer other than the present invention used in the blend type liquid crystal alignment agent, one or more of polyamic acid and polyamic acid derivatives are preferable. As the polymer other than the present invention, the above description of the polymer of the present invention can be referred to for polyamic acid and polyamic acid derivatives, except that they do not contain tetracarboxylic dianhydrides represented by formula (1) as raw materials.

[0187] When using a two-component polymer, for example, one embodiment is to select a polymer having excellent performance in liquid crystal alignment ability as one component, and a polymer having excellent performance in improving the electrical characteristics of a liquid crystal display element as the other component, which is suitable for obtaining an alignment agent with a good balance between liquid crystal alignment ability and electrical characteristics.

[0188] In this case, by controlling the structure and molecular weight of each polymer, the liquid crystal alignment agent in which these polymers are dissolved in a solvent is applied to a substrate as described below, and in the process of forming a thin film by pre-drying, the polymer having excellent performance in liquid crystal alignment ability can be segregated in the upper layer of the thin film, and the polymer having excellent performance in improving the electrical properties of the liquid crystal display element can be segregated in the lower layer of the thin film. For this, the phenomenon in which a polymer with a small surface energy is separated into the upper layer and a polymer with a large surface energy is separated into the lower layer in the mixed polymers can be applied. Such layer separation can be confirmed by checking that the surface energy of the formed liquid crystal alignment film is the same as or close to the surface energy of a film formed by a liquid crystal alignment agent containing only the polymer intended to be segregated in the upper layer.

[0189] Another method for realizing phase separation is to reduce the molecular weight of the polymer to be segregated to the upper layer.

[0190] In the case of a liquid crystal alignment agent consisting of a mixture of polymers, layer separation can be achieved by using polyimide as the polymer to be segregated in the upper layer.

[0191] The tetracarboxylic dianhydride represented by formula (1) may be used as a raw material monomer for the polymer segregated in the upper layer of the thin film, or may be used as a raw material monomer for the polymer segregated in the lower layer of the thin film, or may be used as a raw material monomer for both polymers, but it is more preferable to use it as a raw material monomer for the polymer segregated in the upper layer of the thin film.When applied to a liquid crystal alignment agent for photoalignment, it is more preferable to use it as a raw material monomer for the polymer segregated in the upper layer of the thin film together with a compound having a photoreactive structure.

[0192] The compound having a photoreactive structure may be used as a raw material monomer for a polymer that segregates in the upper layer of the thin film, or may be used as a raw material monomer for a polymer that segregates in the lower layer of the thin film, or may be used as a raw material monomer for both polymers. However, it is more preferable to use the compound having a photoreactive structure as a raw material monomer for a polymer that segregates in the upper layer of the thin film together with the tetracarboxylic dianhydride represented by formula (1).

[0193] The tetracarboxylic dianhydride used for synthesizing the polyamic acid or its derivative that segregates in the upper layer of the thin film can be selected from the known tetracarboxylic dianhydrides exemplified above without any limitation.

[0194] The tetracarboxylic dianhydrides other than the tetracarboxylic dianhydrides represented by formula (1) used for synthesizing the polyamic acid or its derivatives segregated in the upper layer of the thin film are preferably compounds represented by formula (AN-1-1), formula (AN-1-2), formula (AN-2-1), formula (AN-3-1), formula (AN-4-5), formula (AN-4-17) or formula (AN-4-21), more preferably formula (AN-4-17) or formula (AN-4-21). In formula (AN-4-17), m is preferably 4 to 8.

[0195] The diamines used to synthesize the polyamic acid or its derivatives that segregate in the upper layer of the thin film can be selected from the known diamines exemplified above without any limitations.

[0196] As the diamines used to synthesize the polyamic acid or its derivatives segregated in the upper layer of the thin film, it is preferable to use a compound represented by formula (DI-4-1), formula (DI-4-13), formula (DI-4-15), formula (DI-5-1), formula (DI-7-3), or formula (DI-13-1). Among them, it is more preferable to use a compound represented by formula (DI-4-13), formula (DI-4-15), formula (DI-5-1), or formula (DI-13-1). In formula (DI-5-1), m=4 to 8 is preferable. In formula (DI-7-3), m=3, n=1 is preferable.

[0197] The tetracarboxylic dianhydride used to synthesize the polyamic acid or its derivative that segregates in the lower layer of the thin film can be selected from the known tetracarboxylic dianhydrides exemplified above without any limitation.

[0198] As the tetracarboxylic dianhydrides other than the tetracarboxylic dianhydrides represented by formula (1) used for synthesizing the polyamic acid or its derivatives segregating in the lower layer of the thin film, the compounds represented by formula (AN-1-1), formula (AN-1-13), formula (AN-2-1), formula (AN-3-2) or formula (AN-4-21) are preferred, and formula (AN-1-1), formula (AN-2-1) or formula (AN-3-2) are more preferred.

[0199] The tetracarboxylic acid dianhydride used to synthesize the polyamic acid or its derivative that segregates in the lower layer of the thin film preferably contains 10 mol % or more, and more preferably 30 mol % or more, of an aromatic tetracarboxylic acid dianhydride based on the total amount of the tetracarboxylic acid dianhydride.

[0200] The diamines used to synthesize the polyamic acid or its derivatives that segregate in the lower layer of the thin film can be selected from the known diamines exemplified above without any limitations.

[0201] As diamines used to synthesize polyamic acid or its derivatives that segregate in the lower layer of the thin film, compounds represented by formula (DI-4-1), formula (DI-4-2), formula (DI-4-10), formula (DI-4-18), formula (DI-4-19), formula (DI-5-1), formula (DI-5-9), formula (DI-5-28), formula (DI-5-30), formula (DI-13-1), or formula (DIH-1-2) are preferred. In formula (DI-5-1), compounds in which m=1 or 2 are preferred, and in formula (DI-5-30), compounds in which k=2 are preferred. Among these, compounds represented by formula (DI-4-1), formula (DI-4-18), formula (DI-4-19), formula (DI-5-9), formula (DI-13-1), or formula (DIH-1-2) are more preferred.

[0202] The diamines used to synthesize the polyamic acid or its derivatives that segregate in the lower layer of the thin film preferably contain at least one selected from the group consisting of aromatic diamines and aromatic dihydrazides in an amount of 30 mol % or more, and more preferably 50 mol % or more, based on the total amount of the diamines.

[0203] The ratio of the polyamic acid or its derivative segregated in the upper layer of the thin film to the total amount of the polyamic acid or its derivative segregated in the upper layer of the thin film and the polyamic acid or its derivative segregated in the lower layer of the thin film is preferably 5% by weight to 50% by weight, and more preferably 10% by weight to 40% by weight.

[0204] The polyamic acid or derivative thereof of the present invention may be a block polymer containing a first polymer chain and a second polymer chain having a structure different from that of the first polymer chain. The block polymer may further contain another polymer chain having a structure different from that of the first polymer chain and the second polymer chain. For example, a block polymer of a polyamic acid may be prepared by mixing a solution of a specific polyamic acid (PAA1) represented by the formula (PAA) and a mixture of polyamic acid (PAA1) and X 1 and X 2The block polymer of polyamic acid (PAA1) can be formed by mixing and heating solutions of polyamic acid (PAA2) with different combinations of (PAA1) and (PAA2). n1 and (PAA2) n2 (PAA1) n1 and (PAA2) n2 In the block polymer, n1 and n2 are each independently an integer of 1 or more, and preferably each independently an integer of 2 or more. In the raw material composition of the block polymer, the compound represented by formula (1) may be used in any one, two or more, or all of the polymer chains. TIFF0007673614000135.tif3646

[0205] In the block polymer, the tetracarboxylic dianhydride represented by the formula (1) is preferably 1 to 90 mol %, more preferably 10 to 70 mol %, and even more preferably 10 to 50 mol %, based on the total amount of tetracarboxylic dianhydrides used as raw materials.

[0206] Here, the polyamic acid block polymer may be synthesized by mixing two or more kinds of polyamic acids produced individually and then heating them, or by synthesizing two or more kinds of polyamic acids in the same reaction vessel and then heating them, such as by synthesizing a first kind of polyamic acid and then adding the raw material of a second kind of polyamic acid to the same reaction vessel.

[0207] In addition, the liquid crystal aligning agent of the present invention may further contain a solvent from the viewpoint of adjusting the coating property of the liquid crystal aligning agent and the concentration of the polyamic acid or its derivative. The solvent can be applied without any particular limitation as long as it has the ability to dissolve the polymer component. The solvent includes a wide range of solvents that are commonly used in the manufacturing process and applications of polymer components such as polyamic acid and soluble polyimide, and can be appropriately selected depending on the purpose of use. The solvent may be one type or a mixed solvent of two or more types.

[0208] Examples of the solvent include a solvent compatible with the polyamic acid or its derivatives, and other solvents for improving the coating properties.

[0209] Examples of aprotic polar organic solvents which are compatible with polyamic acid or its derivatives include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylimidazolidinone, N-methylcaprolactam, N-methylpropionamide, N,N-dimethylacetamide, dimethylsulfoxide, N,N-dimethylformamide, N,N-diethylformamide, diethylacetamide, N,N-dimethylisobutylamide, γ-butyrolactone, and γ-valerolactone. Of these, N-methyl-2-pyrrolidone, dimethylimidazolidinone, γ-butyrolactone, or γ-valerolactone is preferred.

[0210] Examples of other solvents for improving coating properties include ethylene glycol monoalkyl ethers such as ethylene glycol monobutyl ether and ethylene glycol monotertiary butyl ether, diethylene glycol monoalkyl ethers such as diethylene glycol monoethyl ether, and diethylene glycol dialkyl ethers such as diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, and diethylene glycol butyl methyl ether. In addition, propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether and 1-butoxy-2-propanol, dipropylene glycol monoalkyl ethers such as dipropylene glycol monomethyl ether, triethylene glycol monoalkyl ethers, butyl cellosolve acetate, phenyl acetate, and ester compounds such as these acetates. In addition, dialkyl malonates such as diethyl malonate, alkyl lactates, diisobutyl ketone, diacetone alcohol, 3-methyl-3-methoxybutanol, 4-methyl-2-pentanol, diisobutyl carbinol, tetralin, and isophorone.

[0211] Of these, diisobutyl ketone, 4-methyl-2-pentanol, diisobutyl carbinol, ethylene glycol monobutyl ether, ethylene glycol monotertiary butyl ether, diethylene glycol monoethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, 1-butoxy-2-propanol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, or butyl cellosolve acetate is preferred.

[0212] The polymer concentration in the liquid crystal aligning agent of the present invention is not particularly limited, and an optimal value may be selected according to the various coating methods described below. In general, in order to suppress unevenness and pinholes during coating, the polymer concentration is preferably 0.1 to 30% by weight, more preferably 1 to 10% by weight, based on the weight of the varnish.

[0213] The preferred range of the viscosity of the liquid crystal alignment agent of the present invention varies depending on the application method, the concentration of the polyamic acid or its derivative, the type of polyamic acid or its derivative used, and the type and ratio of the solvent. For example, in the case of application by a printer, the viscosity is 5 to 100 mPa·s (more preferably 10 to 80 mPa·s). If the viscosity is 5 mPa·s or more, a sufficient film thickness is easily obtained, and if the viscosity is 100 mPa·s or less, printing unevenness is easily suppressed. In the case of application by spin coating, the viscosity is suitable to be 5 to 200 mPa·s (more preferably 10 to 100 mPa·s). In the case of application by an inkjet coater, the viscosity is suitable to be 5 to 50 mPa·s (more preferably 5 to 20 mPa·s). The viscosity of the liquid crystal alignment agent is measured by a rotational viscosity measurement method, for example, using a rotational viscometer (TVE-20L type manufactured by Toki Sangyo Co., Ltd.) (measurement temperature: 25°C).

[0214] The liquid crystal alignment agent of the present invention may further contain various additives. Various additives can be selected and used according to the respective purposes in order to improve various properties of the alignment film. Examples are shown below.

[0215] <Alkenyl-substituted nadimide compounds> For example, the liquid crystal alignment agent of the present invention may further contain an alkenyl-substituted nadiimide compound for the purpose of stabilizing the electrical properties of the liquid crystal display element for a long period of time. The alkenyl-substituted nadiimide compound may be used alone or in combination of two or more. For the above purpose, the content of the alkenyl-substituted nadiimide compound is preferably 1 to 50% by weight, more preferably 1 to 30% by weight, and even more preferably 1 to 20% by weight, based on the polyamic acid or its derivative. The alkenyl-substituted nadiimide compound is preferably a compound that can be dissolved in a solvent that dissolves the polyamic acid or its derivative used in the present invention. Preferred alkenyl-substituted nadiimide compounds include the alkenyl-substituted nadiimide compounds disclosed in JP-A-2008-096979, JP-A-2009-109987, and JP-A-2013-242526. Particularly preferred alkenyl-substituted nadimide compounds include bis{4-(arylbicyclo[2.2.1]hept-5-ene-2,3-dicarboximide)phenyl}methane, N,N'-m-xylylene-bis(arylbicyclo[2.2.1]hept-5-ene-2,3-dicarboximide), or N,N'-hexamethylene-bis(arylbicyclo[2.2.1]hept-5-ene-2,3-dicarboximide).

[0216] <Compounds having radically polymerizable unsaturated double bonds> For example, the liquid crystal alignment agent of the present invention may further contain a compound having a radical polymerizable unsaturated double bond for the purpose of stabilizing the electrical characteristics of the liquid crystal display element for a long period of time. The compound having a radical polymerizable unsaturated double bond may be one type of compound or two or more types of compounds. The compound having a radical polymerizable unsaturated double bond does not include an alkenyl-substituted nadiimide compound. Preferred compounds having a radical polymerizable unsaturated double bond include N,N'-methylenebisacrylamide, N,N'-dihydroxyethylene-bisacrylamide, ethylenebisacrylate, 4,4'-methylenebis(N,N-dihydroxyethyleneacrylateaniline), triallyl cyanurate, and other compounds having a radical polymerizable unsaturated double bond disclosed in JP 2009-109987 A, JP 2013-242526 A, WO 2014 / 119682, and WO 2015 / 152014. For the above-mentioned purposes, the content of the compound having a radically polymerizable unsaturated double bond is preferably 1 to 50% by weight, and more preferably 1 to 30% by weight, based on the polyamic acid or its derivative.

[0217] <Oxazine compounds> For example, the liquid crystal aligning agent of the present invention may further contain an oxazine compound for the purpose of stabilizing the electrical properties of a liquid crystal display element for a long period of time. The oxazine compound may be one type of compound or two or more types of compounds. For the above purpose, the content of the oxazine compound is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and even more preferably 1 to 20% by weight, based on the polyamic acid or its derivative.

[0218] The oxazine compound is preferably soluble in the solvent that dissolves polyamic acid or its derivative, and has ring-opening polymerizability.Preferred oxazine compounds include the oxazine compounds represented by formula (OX-3-1), formula (OX-3-9), and formula (OX-3-10), and the oxazine compounds disclosed in JP-A-2007-286597 and JP-A-2013-242526. TIFF0007673614000136.tif72147

[0219] <Oxazoline compounds> For example, the liquid crystal aligning agent of the present invention may further contain an oxazoline compound for the purpose of stabilizing the electrical characteristics of a liquid crystal display element for a long period of time. The oxazoline compound is a compound having an oxazoline structure. The oxazoline compound may be one type of compound or two or more types of compounds. For the above purpose, the content of the oxazoline compound is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and even more preferably 1 to 20% by weight, based on the polyamic acid or its derivative. Preferred oxazoline compounds include the oxazoline compounds disclosed in JP-A-2010-054872 and JP-A-2013-242526. More preferably, 1,3-bis(4,5-dihydro-2-oxazolyl)benzene is used.

[0220] <Epoxy compounds> For example, the liquid crystal aligning agent of the present invention may further contain an epoxy compound for the purpose of stabilizing the electrical characteristics of a liquid crystal display element for a long period of time, improving the hardness of the film, or improving the adhesion to a sealant. The epoxy compound may be one type of compound or two or more types of compounds. For the above purposes, the content of the epoxy compound is preferably 0.1 to 50% by weight, more preferably 1 to 20% by weight, and even more preferably 1 to 10% by weight, based on the polyamic acid or its derivative.

[0221] As the epoxy compound, various compounds having one or more epoxy rings in the molecule can be used. For the purpose of improving the hardness of the film or the adhesion to a sealant, a compound having two or more epoxy rings in the molecule is preferred, and a compound having three or four epoxy rings is more preferred.

[0222] Examples of the epoxy compound include the epoxy compounds disclosed in JP 2009-175715 A, JP 2013-242526 A, JP 2016-170409 A, and WO 2017 / 217413. Preferred epoxy compounds include N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, (3,3',4,4'-diepoxy)bicyclohexyl, 1,4-butanediol glycidyl ether, tris(2,3-epoxypropyl)isocyanurate, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, or N,N,N',N'-tetraglycidyl-m-xylylenediamine. In addition to the above, an oligomer or polymer having an epoxy ring can be added. As the oligomer or polymer having an epoxy ring, the oligomer or polymer disclosed in JP-A-2013-242526 can be used.

[0223] <Silane compounds> For example, the liquid crystal aligning agent of the present invention may further contain a silane compound for the purpose of improving adhesion to a substrate and a sealant. For the above purpose, the content of the silane compound is preferably 0.1 to 30% by weight, more preferably 0.5 to 20% by weight, and further preferably 0.5 to 10% by weight, based on the polyamic acid or its derivative.

[0224] As the silane compound, the silane coupling agents disclosed in JP-A-2013-242526, JP-A-2015-212807, JP-A-2018-173545, and WO 2018 / 181566 can be used. Preferred silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, paraaminophenyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-isocyanatopropyltriethoxysilane, or 3-ureidopropyltriethoxysilane.

[0225] In addition to the additives described above, a compound having a cyclocarbonate group, a hydroxyalkylamide moiety, or a hydroxyl group can be added for the purpose of increasing the strength of the alignment film or stabilizing the electrical characteristics of the liquid crystal display element for a long period of time. Specific compounds include those disclosed in JP 2016-118753 A and WO 2017 / 110976 A. Preferred compounds include the following formulae (HD-1) to (HD-4). These compounds are preferably 0.5 to 50% by weight, more preferably 1 to 30% by weight, and even more preferably 1 to 10% by weight, of the polyamic acid or its derivative. TIFF0007673614000137.tif88126

[0226] In addition, when improved antistatic properties are required, antistatic agents can be used, and when imidization is to proceed at low temperatures, imidization catalysts can be used, such as those disclosed in JP2013-242526A.

[0227] <Liquid crystal alignment film> Next, the liquid crystal alignment film of the present invention will be described. The liquid crystal alignment film of the present invention is formed by using the liquid crystal alignment agent of the present invention. When the liquid crystal alignment agent of the present invention is used to form a liquid crystal alignment film, the liquid crystal alignment film is heated and baked to cause an imidization reaction to form a polyimide-based liquid crystal alignment film. The liquid crystal alignment agent of the present invention can be used for a rubbing alignment film using a rubbing method as a dispensing treatment method, and can also be used for a photo-alignment film using a photo-alignment method as an alignment treatment method if a compound having a photoreactive structure is used as a raw material.

[0228] Hereinafter, a method for forming a liquid crystal alignment film using the photo-alignment liquid crystal aligning agent of the present invention will be described.

[0229] The liquid crystal alignment film of the present invention can be obtained by a normal method of preparing a liquid crystal alignment film from a liquid crystal alignment agent for photo-alignment. The liquid crystal alignment film of the present invention can be obtained, for example, by going through a process of forming a coating film of the liquid crystal alignment agent for photo-alignment of the present invention, a process of heating and drying the coating film to form a film of the liquid crystal alignment agent, a process of irradiating the film of the liquid crystal alignment agent with light to impart anisotropy, and a process of heating and baking the film of the liquid crystal alignment agent to which anisotropy has been imparted. For the liquid crystal alignment film of the present invention, it is preferable to irradiate light after the coating process and the heating and drying process to impart anisotropy, and then go through a heating and baking process.

[0230] The coating film can be formed by applying the liquid crystal alignment agent of the present invention to a substrate in a liquid crystal display element in the same manner as in the preparation of a normal liquid crystal alignment film. The substrate may be made of glass, silicon nitride, acrylic, polycarbonate, polyimide, or the like, which may be provided with an electrode such as ITO (Indium Tin Oxide), IZO (In2O3-ZnO), or IGZO (In-Ga-ZnO4) electrode, or a color filter, or the like.

[0231] Generally known methods for applying a liquid crystal alignment agent to a substrate include a spinner method, a printing method, a dipping method, a dropping method, an inkjet method, etc. These methods are also applicable to the present invention.

[0232] The heat drying step is generally known to be a method of heat treatment in an oven or an infrared furnace, a method of heat treatment on a hot plate, etc. The heat drying step is preferably carried out at a temperature within a range in which the solvent can evaporate, and more preferably at a temperature relatively lower than the temperature in the heat baking step. Specifically, the heat drying temperature is preferably in the range of 30°C to 150°C, more preferably in the range of 50°C to 120°C.

[0233] The heating and baking step can be carried out under conditions necessary for the polyamic acid or its derivative to undergo an imidization reaction. For baking of the coating film, a method of heating in an oven or an infrared furnace, a method of heating on a hot plate, etc. are generally known. These methods can also be applied to the present invention. In general, the baking is preferably carried out at a temperature of about 90 to 300°C for 1 minute to 3 hours, more preferably 120 to 280°C, and even more preferably 150 to 250°C.

[0234] When it is important to improve the anisotropy of the film or the afterimage characteristics when a liquid crystal display device is manufactured, it is preferable to raise the temperature gradually in the heating step, for example, by heating and baking at different temperatures multiple times while raising the temperature stepwise, or by heating while changing the temperature from a low temperature to a high temperature. Also, both heating methods may be combined.

[0235] When firing is performed multiple times at different temperatures, multiple heating devices set to different temperatures may be used, or one heating device may be used and the temperature may be changed sequentially to different temperatures.

[0236] When firing is performed multiple times at different temperatures, the initial firing temperature is preferably 90 to 180 ° C, and the final temperature is preferably 185 ° C to 300 ° C. For example, it is preferable to heat and fire at 110 ° C and then heat and fire at 220 ° C, heat and fire at 110 ° C and then heat and fire at 230 ° C, heat and fire at 130 ° C and then heat and fire at 220 ° C, heat and fire at 150 ° C and then heat and fire at 200 ° C, heat and fire at 150 ° C and then heat and fire at 220 ° C, heat and fire at 150 ° C and then heat and fire at 230 ° C, or heat and fire at 170 ° C and then heat and fire at 200 ° C. It is also preferable to heat and fire the product in more stages while gradually increasing the temperature. When heating and firing is performed in two or more stages with different heating temperatures, the heating time in each heating step is preferably 5 to 30 minutes.

[0237] When firing is performed by changing the temperature from a low temperature to a high temperature, the initial temperature is preferably 90 to 180°C. The final temperature is preferably 185 to 300°C, more preferably 190 to 230°C. The heating time is preferably 5 to 60 minutes, more preferably 20 to 60 minutes. The temperature rise speed can be, for example, 0.5°C / min to 40°C / min. The temperature rise speed during the temperature rise does not have to be constant.

[0238] In the method for forming a liquid crystal alignment film of the present invention, a known photoalignment method can be suitably used as a means for imparting anisotropy to a thin film in order to align liquid crystals in one direction relative to the horizontal and / or vertical directions.

[0239] A method for forming the liquid crystal alignment film of the present invention using a photo-alignment method will be described in detail. The liquid crystal alignment film of the present invention using the photo-alignment method can be formed by heating and drying a coating film, irradiating the thin film with light to impart anisotropy to the thin film, and then heating and baking the film. Alternatively, the liquid crystal alignment film can be formed by heating and drying a coating film, heating and baking the film, and then irradiating the thin film with light. From the viewpoint of liquid crystal alignment, it is preferable to perform the light irradiation step before the heating and baking step.

[0240] Furthermore, in order to increase the liquid crystal alignment ability of the liquid crystal alignment film, the coating film can be irradiated with light while being heated. The light irradiation can be performed in the step of drying the coating film by heating or in the step of baking the coating film by heating, or can be performed between the steps of drying the coating film by heating and baking the coating film by heating. The heating temperature when irradiating light in the step of drying or baking the coating film can be determined by referring to the description of the drying or baking step above. The heating temperature when irradiating light between the drying and baking steps is preferably in the range of 30°C to 150°C, more preferably in the range of 50°C to 110°C.

[0241] As the light, for example, ultraviolet light or visible light including light of a wavelength of 150 to 800 nm can be used. When the compound having a photoreactive structure used as a raw material has a photoisomerization structure or a photodimerization structure, the wavelength is preferably 200 to 500 nm, more preferably 300 to 400 nm. When it has a photodecomposition structure, the wavelength is preferably 150 to 400 nm, more preferably 200 to 300 nm. Polarized light or non-polarized light can be used. These lights are not particularly limited as long as they can impart liquid crystal alignment ability to the thin film, but when it is desired to express a strong alignment control force for the liquid crystal, polarized light is preferable, and linearly polarized light is more preferable.

[0242] The irradiation dose of the linearly polarized light in the light irradiation step is 0.05 to 10 J / cm 2 is preferably 0.1 to 5 J / cm 2 is more preferable. The irradiation angle of the linearly polarized light to the film surface is not particularly limited, but in order to exert a strong alignment control force on the liquid crystal, it is preferable that the irradiation angle is as perpendicular as possible to the film surface from the viewpoint of shortening the alignment treatment time. In addition, the liquid crystal alignment film of the present invention can align the liquid crystal in a direction perpendicular to the polarization direction of the linearly polarized light by irradiating the linearly polarized light.

[0243] The light source used in the light irradiation process can be, without limitation, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a deep UV lamp, a halogen lamp, a metal halide lamp, a high power metal halide lamp, a xenon lamp, a mercury xenon lamp, an excimer lamp, a KrF excimer laser, a fluorescent lamp, an LED lamp, a sodium lamp, a microwave excited electrodeless lamp, and the like.

[0244] The liquid crystal alignment film of the present invention can be suitably obtained by a method including steps other than the steps described above.

[0245] The liquid crystal alignment film of the present invention does not necessarily require a step of washing the film after baking or light irradiation with a washing solution, but a washing step can be provided for the convenience of other steps. Examples of the washing method using a washing solution include brushing, jet spray, steam washing, and ultrasonic washing. These methods may be performed alone or in combination. As the washing solution, pure water or various alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, aromatic hydrocarbons such as benzene, toluene, and xylene, halogen-based solvents such as methylene chloride, and ketones such as acetone and methyl ethyl ketone can be used, but are not limited to these. Of course, these washing solutions are sufficiently purified and have few impurities. Such a washing method can also be applied to the washing step in the formation of the liquid crystal alignment film of the present invention.

[0246] In order to enhance the liquid crystal alignment ability of the liquid crystal alignment film of the present invention, an annealing treatment using heat or light can be used before or after the heating and baking process, or before or after irradiation with polarized or unpolarized light. In the annealing treatment, the annealing temperature is 30 to 180°C, preferably 50 to 150°C, and the time is preferably 1 minute to 2 hours. Examples of annealing light used in the annealing treatment include UV lamps, fluorescent lamps, and LED lamps. The amount of light irradiation is 0.3 to 10 J / cm. 2 It is preferable that:

[0247] When an alignment film is formed from the liquid crystal alignment agent of the present invention using a rubbing method, it can be obtained by a conventional method for producing an alignment film from a liquid crystal alignment agent for rubbing. For example, the method described in International Publication No. 2019 / 031604 can be referenced.

[0248] The thickness of the liquid crystal alignment film of the present invention is not particularly limited, but is preferably 10 to 300 nm, more preferably 30 to 150 nm. The thickness of the liquid crystal alignment film of the present invention can be measured by a known thickness measuring device such as a step gauge or an ellipsometer.

[0249] The liquid crystal alignment film of the present invention is characterized by having a particularly large anisotropy of alignment. The magnitude of such anisotropy can be evaluated by a method using polarized IR described in JP-A-2005-275364, etc., and can also be evaluated by a method using ellipsometry. In detail, the retardation value of the liquid crystal alignment film can be measured by a spectroscopic ellipsometer. The retardation value of the film increases in proportion to the degree of orientation of the polymer main chain.

[0250] The liquid crystal alignment film of the present invention can be used for controlling the alignment of liquid crystal compositions for liquid crystal displays such as smartphones, tablets, in-vehicle monitors, and televisions. In addition to the alignment of liquid crystal compositions for liquid crystal displays, the film can be used for controlling the alignment of all other liquid crystal materials, such as optical compensation materials and wideband variable phase shifters in the microwave and millimeter wave bands using liquid crystals. In addition, since the liquid crystal alignment film of the present invention has a large anisotropy, it can be used alone for optical compensation materials.

[0251] <Liquid crystal display element> The liquid crystal display element of the present invention is characterized by having the liquid crystal alignment film of the present invention, and can realize high display quality due to its excellent afterimage characteristics, contrast and VHR reliability.

[0252] The liquid crystal display element of the present invention will be described in detail. The present invention is a liquid crystal display element having a pair of substrates arranged opposite to each other, electrodes formed on one or both of the opposing surfaces of each of the pair of substrates, a liquid crystal alignment film formed on the opposing surface of each of the pair of substrates, a liquid crystal layer formed between the pair of substrates, a pair of polarizing films arranged to sandwich the opposing substrates, a backlight, and a driving device, in which the liquid crystal alignment film is composed of the liquid crystal alignment film of the present invention.

[0253] The electrode is not particularly limited as long as it is an electrode formed on one side of the substrate. Examples of such electrodes include ITO and metal deposition films. The electrode may be formed on the entire surface of one side of the substrate, or may be formed in a desired shape, for example, patterned. Examples of the desired shape of the electrode include a comb-shaped or zigzag structure. The electrode may be formed on one of the pair of substrates, or on both substrates. The form of electrode formation differs depending on the type of liquid crystal display element. For example, in the case of an IPS type liquid crystal display element (horizontal electric field type liquid crystal display element), an electrode is disposed on one of the pair of substrates, and in the case of other liquid crystal display elements, an electrode is disposed on both of the pair of substrates. The liquid crystal alignment film is formed on the substrate or the electrode.

[0254] In the case of a homogeneously aligned liquid crystal display element (e.g., IPS, FFS, etc.), the structure includes at least a backlight, a first polarizing film, a first substrate, a first liquid crystal alignment film, a liquid crystal layer, a second substrate, and a second polarizing film from the backlight side, and the polarizing axis of the polarizing film is set so that the polarizing axis of the first polarizing film (direction of polarized light absorption) crosses (preferably perpendicular) with the polarizing axis of the second polarizing film. At this time, the polarizing axis of the first polarizing film can be set so that it is parallel to the liquid crystal alignment direction or perpendicular to the liquid crystal alignment direction. A liquid crystal display element in which the polarizing axis of the first polarizing film is set so that it is parallel to the liquid crystal alignment direction is called O-mode, and a liquid crystal display element in which it is set so that it is perpendicular to the liquid crystal alignment direction is called E-mode. The liquid crystal alignment film of the present invention can be applied to either O-mode or E-mode, and can be selected according to the purpose.

[0255] Many photoisomerization materials use compounds with dichroism. Therefore, when the polarization axis of the polarized light irradiated to impart anisotropy to the liquid crystal alignment agent is aligned parallel to the polarization axis of the polarized light from the polarizing film arranged on the backlight side (when the liquid crystal alignment agent of the present invention is used, the O-mode arrangement is used), the transmittance of the liquid crystal alignment film in the light absorption wavelength range increases. Therefore, the transmittance of the liquid crystal display element can be further improved.

[0256] The liquid crystal layer is formed by sandwiching a liquid crystal composition between the pair of substrates on which the liquid crystal alignment film is formed, and when the liquid crystal layer is formed, a spacer such as fine particles or a resin sheet that is interposed between the pair of substrates to form an appropriate gap can be used as necessary.

[0257] Known methods for forming a liquid crystal layer include a vacuum injection method and an ODF (One Drop Fill) method.

[0258] In the vacuum injection method, a gap (cell gap) is provided so that the liquid crystal alignment film surfaces face each other, and a sealant is printed leaving an injection port for the liquid crystal, and then the substrates are bonded together. After the liquid crystal is injected into the cell gap defined by the substrate surface and the sealant using a vacuum pressure difference, the injection port is sealed to produce a liquid crystal display element.

[0259] In the ODF method, a sealant is printed on the outer periphery of the liquid crystal alignment film of one of the pair of substrates, liquid crystal is dropped on the area inside the sealant, and then the other substrate is attached so that the liquid crystal alignment film faces the other substrate. The liquid crystal is then spread over the entire surface of the substrate, and then the entire surface of the substrate is irradiated with ultraviolet light to harden the sealant, thereby producing a liquid crystal display element.

[0260] In addition to UV curing types, heat curing types are also known as sealants used for bonding substrates. The sealant can be printed by screen printing, for example.

[0261] The liquid crystal composition is not particularly limited, and various liquid crystal compositions having positive or negative dielectric anisotropy can be used. Preferred liquid crystal compositions having positive dielectric anisotropy are described in Japanese Patent No. 3086228, Japanese Patent No. 2635435, JP-A-5-501735, JP-A-8-157826, JP-A-8-231960, JP-A-9-241644 (EP885272A1), JP-A-9-302346 (EP806466A1), JP-A-8-199168 (EP722998A1), and the like. ), JP-A-9-235552, JP-A-9-255956, JP-A-9-241643 (EP885271A1), JP-A-10-204016 (EP844229A1), JP-A-10-204436, JP-A-10-231482, JP-A-2000-087040, JP-A-2001-48822, and the like.

[0262] Preferable examples of the liquid crystal composition having negative dielectric anisotropy include those disclosed in JP-A-57-114532, JP-A-2-4725, JP-A-4-224885, JP-A-8-40953, JP-A-8-104869, JP-A-10-168076, JP-A-10-168453, JP-A-10-236989, JP-A-10-236990, JP-A-10-236992, JP-A-10-236993, JP-A-10-236994, JP-A-10-237000, JP-A-10-237004, JP-A-10-237024, JP-A-10-237035, JP-A-10-237075, and JP-A-10-237076. , JP-A-10-237448 (EP967261A1), JP-A-10-287874, JP-A-10-287875, JP-A-10-291945, JP-A-11-029581, JP-A-11-080049, JP-A-2000-256307, JP-A-2001-019965, JP-A-2001-072626, JP-A-2001-192657, JP-A-2010-037428, WO 2011 / 024666, WO 2010 / 072370, JP-T-2010-537010, JP-A-2012-077201, JP-A-2009-084362, and the like.

[0263] There is no problem in using a liquid crystal composition having a positive or negative dielectric anisotropy by adding one or more optically active compounds.

[0264] For example, the liquid crystal composition used in the liquid crystal display element of the present invention may further contain additives, for example, from the viewpoint of improving the alignment. Such additives include photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, dyes, defoamers, polymerization initiators, and polymerization inhibitors. Preferred photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, dyes, defoamers, polymerization initiators, and polymerization inhibitors include compounds disclosed in International Publication WO 2015 / 146330 and the like.

[0265] A polymerizable compound can be mixed into the liquid crystal composition to adapt it to a liquid crystal display element of PSA (polymer sustained alignment) mode. Preferred examples of the polymerizable compound are compounds having a polymerizable group, such as acrylate, methacrylate, vinyl compound, vinyloxy compound, propenyl ether, epoxy compound (oxirane, oxetane), and vinyl ketone. Preferred compounds include those disclosed in International Publication WO 2015 / 146330 and the like. EXAMPLES

[0266] The present invention will now be described with reference to examples, in which the evaluation methods and compounds used are as follows.

[0267] <Weight average molecular weight (Mw)> The weight average molecular weight of the polyamic acid was measured by the GPC method using a 2695 Separation Module 2414 Differential Refractometer (Waters) and calculated as polystyrene. The obtained polyamic acid was diluted with a phosphoric acid-DMF mixed solution (phosphoric acid / DMF=0.6 / 100: weight ratio) so that the polyamic acid concentration was about 2 wt%. The column used was HSPgel RT MB-M (Waters), and the mixed solution was used as a developer, and the measurement was performed under the conditions of a column temperature of 50°C and a flow rate of 0.40 mL / min. The standard polystyrene used was TSK standard polystyrene (Tosoh Corporation).

[0268] <AC Afterimage Measurement and Contrast Measurement> The AC afterimage was measured according to the method described in International Publication No. 2000 / 43833. Specifically, the luminance-voltage characteristic (B-V characteristic) of the fabricated liquid crystal cell was measured and taken as the luminance-voltage characteristic before stress application: B(before). Next, after applying an alternating current of 4.5 V and 60 Hz to the liquid crystal cell for 20 minutes, it was short-circuited for 1 second, and the luminance-voltage characteristic (B-V characteristic) was measured again. This was taken as the luminance-voltage characteristic after stress application: B(after). Here, using the luminance at a voltage of 1.3 V for each measured luminance-voltage characteristic, the luminance change rate ΔB(%) was obtained by the following formula. The smaller the value of ΔB(%), the more the occurrence of the AC afterimage can be suppressed, that is, the better the afterimage characteristics. If ΔB is 3% or less, it can be said that the afterimage characteristics are good. However, in recent years, the demand for afterimage characteristics has been further increasing, and a lower value is more preferable. ΔB(%) = {[B(after) - B(before)] / B(before)} × 100 Also, the contrast (CR) was obtained using the ratio of the minimum luminance to the maximum luminance in the B-V characteristic before stress application. The larger the value of CR, the clearer the light and dark display, which means that the contrast is good, and it can be said that it has an excellent contrast of 3000 or more. CR = B(before) max / B(before) min In the formula, B(before) max represents the maximum luminance in the B-V characteristic before stress application, and B(before) min represents the minimum luminance in the B-V characteristic before stress application.

[0269] <Evaluation of Voltage Holding Ratio (VHR) Reliability> The voltage holding ratio (VHR) of the liquid crystal display element was measured by applying a square wave of ±5V to the cell at 60°C according to the method described in Mizushima et al., 14th Liquid Crystal Symposium Proceedings, p78 (1988). The VHR at this time was taken as VHR(before). The voltage holding ratio is an index showing the extent to which the applied voltage is retained after a frame cycle, and a value of 100% means that all the charge is retained. The cell was exposed to an LED backlight for 300 hours, and the VHR was measured again. The VHR at this time was taken as VHR(after). VHR reliability was evaluated based on the VHR decline rate calculated using the following formula. The smaller the VHR decline rate, the higher the VHR reliability and the higher the stability against light. VHR decline rate (%) ={[VHR(after)-VHR(before)] / VHR(before)}×100

[0270] <Tetracarboxylic acid dianhydride> TIFF0007673614000138.tif117165

[0271] <Diamines> TIFF0007673614000139.tif52122 TIFF0007673614000140.tif44122 TIFF0007673614000141.tif44110 The value of m in formula (AN-1-2), formula (AN-4-17), formula (DI-5-1) or formula (DIH-1-2) is shown in Tables 1 to 3.

[0272] <Solvent> NMP: N-methyl-2-pyrrolidone BC: Butyl cellosolve (ethylene glycol monobutyl ether) <Additives> Ad-1: 3-aminopropyltriethoxysilane Ad-2: 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane Ad-3: (3,3',4,4'-diepoxy)bicyclohexyl Ad-4: 1,3-bis(4,5-dihydro-2-oxazolyl)benzene

[0273] [Synthesis Example 1] Synthesis of Formula (2-1) The compound represented by formula (2-1) was synthesized according to the following scheme. TIFF0007673614000142.tif71140

[0274] <Synthesis of Formula (2C-1)> Sodium ethoxide (6.98 g, 97.5 mmol) was placed in a 500 mL three-neck flask equipped with a nitrogen inlet tube, and DMF (80 mL) was added and stirred. A solution of the compound represented by formula (2A-1) (20.0 g, 81.2 mmol) in DMF (40 mL) was added dropwise to this solution under ice cooling (ice bath), and the mixture was stirred for 0.5 hours. Next, a solution of the compound represented by formula (2B-1) (10.7 g, 40.6 mmol) in DMF (160 mL) was added dropwise to this solution under ice cooling (ice bath), and the mixture was stirred for 4 hours. After the reaction, water (300 mL) and ethyl acetate (500 mL) were added and the mixture was separated. The organic layer was washed twice with water (500 mL), and the solution dried over sodium sulfate was distilled under reduced pressure to obtain a crude product. This crude product was purified by silica gel column chromatography using a mixed solvent of hexane:ethyl acetate=5:1 as an eluent to obtain 18.5 g of the compound represented by formula (2C-1) in a yield of 77%. <Synthesis of formula (2D-1)> The compound represented by formula (2C-1) (18.5 g, 31.1 mmol) was placed in a 300 mL three-neck flask equipped with a nitrogen inlet tube, and ethanol (110 mL) was added and stirred. A solution of sodium hydroxide (14.9 g, 373.3 mmol) in water (50 mL) was added to this solution, and the mixture was heated under reflux for 3 hours. After the reaction, the mixture was cooled to room temperature, and the ethanol was removed under reduced pressure, and the solution was acidified with 6 M hydrochloric acid. The solid obtained was filtered and dried, and the compound represented by formula (2D-1) was obtained in an amount of 12.5 g and a yield of 94%. <Synthesis of Formula (2E-1)> The compound represented by formula (2D-1) (12.5 g, 29.3 mmol) was placed in a 200 mL three-neck flask equipped with a nitrogen inlet tube, and water (50 mL) was added and stirred. Concentrated sulfuric acid (1.72 mL, 32.2 mmol) was added to this solution, and the mixture was heated under reflux for 6 hours. After the reaction, the mixture was cooled to room temperature, and the precipitated solid was filtered and dried to obtain the compound represented by formula (2E-1) in an amount of 8.2 g and a yield of 83%. <Synthesis of formula (2-1)> The compound represented by formula (2E-1) (8.2 g, 24.2 mmol) was placed in a 100 mL three-neck flask equipped with a nitrogen inlet tube, and acetic anhydride (50 mL) was added and stirred. The solution was heated under reflux for 6 hours. After the reaction, the mixture was cooled to room temperature, and the precipitated solid was filtered and dried to obtain the compound represented by formula (2-1) in an amount of 6.4 g and a yield of 87%. 1 H-NMR (500MHz, DMSO-D6): δ 7.19 (s, 4H), 3.51-3.58 (m, 2H), 3.08-3.11 (m, 2H), 2.85-2.95 (m, 4H), 2.72-2.77 (m, 2H).

[0275] [Synthesis Example 2] Synthesis of Formula (3-2) The compound represented by formula (3-2) was synthesized according to the following scheme. TIFF0007673614000143.tif145126

[0276] <Synthesis of Formula (3C-2)> Sodium ethoxide (14.0 g, 195 mmol) was placed in a 500 mL three-neck flask equipped with a nitrogen inlet tube, and DMF (160 mL) was added and stirred. A solution of the compound represented by formula (3A-2) (40.0 g, 162 mmol) in DMF (40 mL) was added dropwise to this solution under ice cooling (ice bath), and the mixture was stirred for 0.5 hours. Next, a solution of the compound represented by formula (3B-2) (23.2 g, 195 mmol) in DMF (40 mL) was added dropwise to this solution under ice cooling (ice bath), and the mixture was stirred for 4 hours. After the reaction, water (400 mL) and ethyl acetate (600 mL) were added and the mixture was separated. The organic layer was washed twice with water (500 mL), and the solution dried over sodium sulfate was distilled under reduced pressure to obtain a crude product. This crude product was purified by silica gel column chromatography using a mixed solvent of hexane:ethyl acetate=5:1 as an eluent to obtain 46.1 g of the compound represented by formula (3C-2) in a yield of 100%. <Synthesis of Formula (3E-2)> A compound represented by formula (3C-2) (46.1 g, 162 mmol) was placed in a 500 mL three-neck flask equipped with a nitrogen inlet tube, and acetonitrile (150 mL) was added and stirred. To this solution, a compound represented by formula (3D-2) (23.0 g, 73.6 mmol), cesium carbonate (96.0 g, 295 mmol), and Pd-132 (0.55 g, 0.74 mmol) were added, and the mixture was heated under reflux for 8 hours. After the reaction, water (200 mL) and ethyl acetate (200 mL) were added and the mixture was separated. The organic layer was washed twice with water (200 mL), and the solution dried over sodium sulfate was distilled under reduced pressure to obtain a crude product. This crude product was purified by silica gel column chromatography using a mixed solvent of hexane:ethyl acetate = 5:1 as an eluent, and a compound represented by formula (3E-2) was obtained in an amount of 36.7 g and a yield of 69%. <Synthesis of Formula (3F-2)> The compound represented by formula (3E-2) (36.7 g, 51.0 mmol) was placed in an autoclave, and THF (800 mL) was added. Pd / C (Pd: 5 wt%, 1.8 g) was added to this solution. The autoclave was replaced with nitrogen and then with hydrogen, and the reaction was carried out for 24 hours. After the reaction, the mixture was filtered and the solution was distilled under reduced pressure to obtain a crude product. This crude product was purified by silica gel column chromatography using a mixed solvent of hexane:ethyl acetate = 1:1 as an eluent, and the compound represented by formula (3F-2) was obtained in an amount of 37.1 g and a yield of 100%. <Synthesis of Formula (3G-2)> The compound represented by formula (3F-2) (37.9 g, 51.0 mmol) was placed in a 500 mL three-neck flask equipped with a nitrogen inlet tube, and ethanol (200 mL) was added and stirred. A solution of sodium hydroxide (24.5 g, 612 mmol) in water (100 mL) was added to this solution, and the mixture was heated under reflux for 3 hours. After the reaction, the mixture was cooled to room temperature, and the ethanol was removed under reduced pressure, and the solution was acidified with 6 M hydrochloric acid. The solid obtained was filtered and dried, and the compound represented by formula (3G-2) was obtained in an amount of 27.5 g and a yield of 96%. <Synthesis of Formula (3H-2)> The compound represented by formula (3G-2) (26.7 g, 47.8 mmol) was placed in a 200 mL three-neck flask equipped with a nitrogen inlet tube, and water (100 mL) was added and stirred. Concentrated sulfuric acid (1.80 mL, 52.5 mmol) was added to this solution, and the mixture was heated under reflux for 6 hours. After the reaction, the mixture was cooled to room temperature, and the precipitated solid was filtered and dried to obtain the compound represented by formula (3H-2) in an amount of 20.2 g and a yield of 90%. <Synthesis of formula (3-2)> The compound represented by formula (3H-2) (20.2 g, 43.0 mmol) was placed in a 100 mL three-neck flask equipped with a nitrogen inlet tube, and acetic anhydride (130 mL) was added and stirred. The solution was heated under reflux for 6 hours. After the reaction, the mixture was cooled to room temperature, and the precipitated solid was filtered and dried to obtain the compound represented by formula (3-2) in an amount of 16.5 g and a yield of 88%. 1H-NMR (500MHz, DMSO-D6): δ 7.56 (d, J = 7.5Hz, 4H), 7.28 (d, J = 7.5Hz, 4H), 3.22-3.29 (m, 2H), 3.03-3.09 (m, 2H), 2.45-2.80 (m, 2H), 2.62 (t, J = 6.8Hz, 4H), 1.59-1.84 (m, 8H).

[0277] [Synthesis Example 3] Synthesis of Formula (2-2) The compound represented by formula (2-2) was synthesized according to the following scheme. TIFF0007673614000144.tif72155

[0278] <Synthesis of Formula (2C-2)> Sodium ethoxide (6.63 g, 92.6 mmol) was placed in a 1000 mL three-neck flask equipped with a nitrogen inlet tube, and DMF (80 mL) was added and stirred. A solution of the compound represented by formula (2A-2) (19.0 g, 77.2 mmol) in DMF (40 mL) was added dropwise to this solution under ice cooling (ice bath), and the mixture was stirred for 0.5 hours. Next, a solution of the compound represented by formula (2B-2) (12.6 g, 37.0 mmol) in DMF (150 mL) was added dropwise to this solution under ice cooling (ice bath), and the mixture was stirred for 3 hours. After the reaction, water (300 mL) and ethyl acetate (600 mL) were added and the mixture was separated. The organic layer was washed twice with water (400 mL), and the solution dried over sodium sulfate was distilled under reduced pressure to obtain a crude product. This crude product was purified by silica gel column chromatography using a mixed solvent of hexane:ethyl acetate=9:1 as an eluent to obtain the compound represented by formula (2C-2) in an amount of 20.3 g and a yield of 82%. <Synthesis of formula (2D-2)> The compound represented by formula (2C-2) (20.3 g, 30.2 mmol) was placed in a 500 mL three-neck flask equipped with a nitrogen inlet tube, and ethanol (120 mL) was added and stirred. A solution of sodium hydroxide (14.5 g, 362.3 mmol) in water (60 mL) was added to this solution, and the mixture was heated under reflux for 4 hours. After the reaction, the mixture was cooled to room temperature, and the ethanol was removed by distillation under reduced pressure, and the solution was made acidic with 6 M hydrochloric acid. This solution was extracted with ethyl acetate (200 mL x 5 times). The organic layer was dried over sodium sulfate, and the solution was removed by distillation under reduced pressure to obtain the compound represented by formula (2D-2) in an amount of 15.1 g and a yield of 100%. <Synthesis of Formula (2E-2)> The compound represented by formula (2D-2) (15.1 g, 30.1 mmol) was placed in a 200 mL three-neck flask equipped with a nitrogen inlet tube, and water (60 mL) was added and stirred. Concentrated sulfuric acid (1.77 mL, 33.2 mmol) was added to this solution, and the mixture was heated under reflux for 7 hours. After the reaction, the mixture was cooled to room temperature, and the precipitated solid was filtered and dried to obtain the compound represented by formula (2E-2) in an amount of 9.5 g and a yield of 76%. <Synthesis of formula (2-2)> The compound represented by formula (2E-2) (9.5 g, 22.8 mmol) was placed in a 100 mL three-neck flask equipped with a nitrogen inlet tube, and acetic anhydride (50 mL) was added and stirred. The solution was heated under reflux for 6 hours. After the reaction, the mixture was cooled to room temperature, and the precipitated solid was filtered and dried to obtain the compound represented by formula (2-2) in an amount of 6.1 g and a yield of 70%. 1 H-NMR (500MHz, DMSO-D6): δ 7.61 (d, J = 7.5Hz, 4H), 7.33 (d, J = 8.5Hz, 4H), 3.57-3.64 (m, 2H), 3.16 (dd, J = 5.2, 13.7Hz, 2H), 2.91-3.02 (m, 4H), 2.80 (dd, J = 7.0, 18.5Hz, 2H).

[0279] [Synthesis Example 4] Synthesis of Formula (4-3) The compound represented by formula (4-3) was synthesized according to the following scheme. TIFF0007673614000145.tif128155

[0280] <Synthesis of Formula (4C-3)> Sodium ethoxide (17.5 g, 243.7 mmol) was placed in a 1000 mL three-neck flask equipped with a nitrogen inlet tube, and DMF (200 mL) was added and stirred. A solution of the compound represented by formula (4A-3) (50.0 g, 203.0 mmol) in DMF (50 mL) was added dropwise to this solution under ice cooling (ice bath), and the mixture was stirred for 0.5 hours. Next, a solution of the compound represented by formula (4B-3) (41.8 g, 243.7 mmol) in DMF (50 mL) was added dropwise to this solution under ice cooling (ice bath), and the mixture was stirred for 23 hours. After the reaction, water (300 mL) and ethyl acetate (500 mL) were added and the mixture was separated. The organic layer was washed twice with water (400 mL), and the solution dried over sodium sulfate was distilled under reduced pressure to obtain a crude product. This crude product was purified by silica gel column chromatography using a mixed solvent of hexane:ethyl acetate=10:1 as an eluent to obtain the compound represented by formula (4C-3) in an amount of 62.0 g and a yield of 91%. <Synthesis of Formula (4E-3)> In a 2000mL three-neck flask equipped with a nitrogen inlet tube, the compound represented by formula (4D-3) (14.5g, 77.9mmol) and potassium carbonate (107.7g, 779.2mmol) were placed, and DMF (700mL) was added and stirred. To this solution, the compound represented by formula (4C-3) (60.4g, 179.2mmol) and potassium iodide (0.39g, 2.3mmol) were added and reacted at 80°C for 42 hours. After the reaction, water (500mL) and ethyl acetate (800mL) were added and separated. The organic layer was washed twice with water (400mL), and the solution dried over sodium sulfate was distilled under reduced pressure to obtain a crude product. This crude product was purified by silica gel column chromatography using a mixed solvent of hexane:ethyl acetate = 4:1 as an eluent, and the compound represented by formula (4E-3) was obtained in an amount of 48.3g and a yield of 79%. <Synthesis of Formula (4F-3)> A compound represented by formula (4E-3) (46.8 g, 59.5 mmol) was placed in a 1000 mL three-neck flask equipped with a nitrogen inlet tube, and ethanol (280 mL) was added and stirred. A solution of sodium hydroxide (28.5 g, 713.4 mmol) in water (140 mL) was added to this solution, and the mixture was heated under reflux for 4 hours. After the reaction, the mixture was cooled to room temperature, and the ethanol was removed under reduced pressure, and the solution was acidified with 6 M hydrochloric acid. The solid obtained was filtered and dried, and the compound represented by formula (4F-3) was obtained in an amount of 36.7 g and a yield of 100%. <Synthesis of formula (4G-3)> The compound represented by formula (4F-3) (36.7 g, 59.4 mmol) was placed in a 300 mL three-neck flask equipped with a nitrogen inlet tube, and water (140 mL) was added and stirred. Concentrated sulfuric acid (3.49 mL, 65.4 mmol) was added to this solution, and the mixture was heated under reflux for 24 hours. After the reaction, the mixture was cooled to room temperature, and the precipitated solid was filtered and dried to obtain the compound represented by formula (4G-3) in an amount of 30.9 g and a yield of 98%. <Synthesis of formula (4-3)> The compound represented by formula (4G-3) (30.9 g, 58.2 mmol) was placed in a 300 mL three-neck flask equipped with a nitrogen inlet tube, and acetic anhydride (150 mL) was added and stirred. The solution was heated under reflux for 6 hours. After the reaction, the mixture was cooled to room temperature, and the precipitated solid was filtered and dried to obtain the compound represented by formula (4-3) in an amount of 26.4 g and a yield of 92%. 1 H-NMR (500MHz, DMSO-D6): δ 7.52 (d, J = 9.0Hz, 4H), 6.98 (d, J = 8.5Hz, 4H), 3.99 (t, J = 6.5Hz, 4H), 3.21-3.28 (m, 2H), 3.07 (dd, J = 9.2, 17.7, 2H), 2.77 (dd, J = 7.0, 18.5Hz, 2H), 1.81-1.88 (m, 2H), 1.63-1.78 (m, 6H), 1.42-1.56 (m, 4H).

[0281] <Preparation of Varnish> The varnishes used in the present embodiment and the comparative examples were prepared by the following procedure. Here, the varnishes A1 to A18 prepared in the varnish preparation examples 1 to 18 are solutions of polyamic acid obtained by reacting at least one compound having a photoreactive structure as one of the raw materials. The blend varnishes B1 to B3 prepared in the varnish preparation examples 19 to 21 are solutions of polyamic acid obtained without using a compound having a photoreactive structure as one of the raw materials, and are used by blending with the varnishes A1 to A18. The varnishes C1 to C14 prepared in the varnish preparation examples 22 to 35 are solutions of block polymers of polyamic acid obtained by reacting at least one compound having a photoreactive structure as one of the raw materials, and the varnishes C1 to C14 may be used alone as a liquid crystal alignment agent, or may be used by blending with the blend varnishes B1 to B3.

[0282] [Varnish Preparation Example 1] Preparation of Varnish A1 In a 100mL three-neck flask equipped with a stirring blade and a nitrogen inlet tube, 1.02g of the compound represented by formula (V-2-1), 0.0717g of the compound represented by formula (DI-13-1), and 0.0682g of the compound represented by formula (DI-4-13) were placed, and 17.0g of N-methyl-2-pyrrolidone was added and stirred. 0.970g of the compound represented by formula (2-1) and 0.869g of the compound represented by formula (AN-4-17, m = 8) were added to this solution, and the solution was stirred at room temperature for 12 hours. 15.0g of NMP and 15.0g of BC were added thereto, and the solution was heated and stirred at 70 ° C until the weight average molecular weight of the solute polymer reached the desired weight average molecular weight, and a varnish A1 with a weight average molecular weight of the solute of approximately 14,000 and a polymer concentration of 6 wt% was obtained.

[0283] [Varnish Preparation Examples 2 to 21] Preparation of Varnishes A2 to A18 and Varnishes B1 to B3 Varnishes A2 to A18 with a resin concentration of 6% by weight were prepared in the same manner as in Preparation Example 1, except that the compounds used as diamines and tetracarboxylic dianhydrides were changed as shown in Table 1. Varnishes B1 to B3 were prepared in the same manner as in Preparation Example 1, except that the compounds used as diamines and tetracarboxylic dianhydrides were changed as shown in Table 2. In varnishes B1 to B3, the conditions of heating and stirring were adjusted so that the weight average molecular weight of the polymer was about 50,000. The weight average molecular weight of the generated polymer is shown in Tables 1 and 2 together with the results of Preparation Example 1. In Table 1, in a preparation example in which two or more compounds are listed as diamines, it means that all of the compounds were used together as diamines, and in a preparation example in which two or more compounds are listed as tetracarboxylic dianhydrides, it means that all of the compounds were used together as tetracarboxylic dianhydrides. The numbers in square brackets represent the compounding ratio (mol%), and blanks mean that the compound corresponding to that column was not used. The same applies to Tables 2 and 3.

[0284] [Table 1] TIFF0007673614000146.tif209169

[0285] [Table 2] TIFF0007673614000147.tif43170

[0286] [Varnish Preparation Example 22] Preparation of Varnish C1 In this preparation example, a polyamic acid block polymer was synthesized by carrying out a two-stage polymerization process. (1) First-stage polymerization process In a 100mL three-neck flask equipped with a stirring blade and a nitrogen inlet tube, 0.0707g of the compound represented by formula (DI-4-1), 0.175g of the compound represented by formula (DI-13-1), and 0.267g of the compound represented by formula (DI-4-19) were placed, and 15.0g of N-methyl-2-pyrrolidone was added and stirred. 0.143g of the compound represented by formula (AN-3-2) and 0.513g of the compound represented by formula (AN-2-1) were added to this solution, and stirring was continued at room temperature for 6 hours to obtain a first polyamic acid solution.

[0287] (2) Second-stage polymerization process In the flask where the first polymerization step was carried out, 0.139g of the compound represented by formula (V-2-1), 0.530g of the compound represented by formula (V-2-13), 0.175g of the compound represented by formula (DI-13-1), 0.593g of the compound represented by formula (2-1), 0.266g of the compound represented by formula (AN-4-17, m = 8), 0.0641g of the compound represented by formula (AN-2-1), and 0.0648g of the compound represented by formula (AN-1-1) were added, and 17.0g of N-methyl-2-pyrrolidone was added, and the mixture was stirred at room temperature for 24 hours to obtain a mixed solution of the first polyamic acid and the second polyamic acid. BC (15.0g) was added to this reaction solution, and the mixture was stirred for 8 hours while heating to 60 ° C., to obtain a polyamic acid block polymer solution with a polymer concentration of 6 wt%. This polyamic acid block polymer solution is called varnish C1.

[0288] [Varnish Preparation Examples 23-35] Preparation of Varnishes C2-C14 Varnishes C2 to C14 having a resin concentration of 6% by weight were prepared in the same manner as in Preparation Example 22, except that the compounds used as diamines and tetracarboxylic dianhydrides were changed as shown in Table 3. The diamines and tetracarboxylic dianhydrides used are shown in Table 3 together with the results of Preparation Example 22.

[0289] [Table 3] TIFF0007673614000148.tif228167

[0290] [Example 1] <Preparation of Liquid Crystal Alignment Agent> Varnish A1 was diluted with an NMP·BC mixed solution (NMP / BC = 7 / 3 weight ratio) so that the polymer concentration became 4% by weight and stirred to prepare a liquid crystal alignment agent E1. <Measurement of Contrast and Measurement of AC Afterimage> Liquid crystal alignment agent 1 was applied to a glass substrate with FFS electrodes and a glass substrate with column spacers by the spinner method. After application, the substrate was heated at 60 °C for 80 seconds to evaporate the solvent, and then, using a Multi Light ML-501C / B manufactured byUSHIO INC., linearly polarized ultraviolet light was irradiated from the vertical direction to the substrate through a polarizing plate. At this time, the exposure energy was measured using a UV integrated light meter UIT-150 (light receiver: UVD-S365) manufactured by USHIO INC., and the exposure time was adjusted so that it became 2.0 ± 0.1 J / cm 2 at a wavelength of 365 nm. Then, a baking treatment was performed at 220 °C for 30 minutes to form a liquid crystal alignment film with a film thickness of approximately 100 nm. Next, two substrates on which these liquid crystal alignment films were formed were bonded with the surfaces on which the liquid crystal alignment films were formed facing each other, and a gap for injecting a liquid crystal composition was provided between the opposing liquid crystal alignment films. At this time, the polarization directions of the linearly polarized light irradiated to each liquid crystal alignment film were made parallel. A positive liquid crystal composition A was injected into these cells to fabricate a liquid crystal cell (liquid crystal display element) with a cell thickness of 5 μm.

[0291] <Positive Liquid Crystal Composition A> TIFF0007673614000149.tif17393 (Physical Property Values) Phase transition temperature NI: 100.1 °C, dielectric anisotropy Δη: 5.1, refractive index anisotropy Δn: 0.093, viscosity η: 25.6 mPa·s.

[0292] Using the fabricated liquid crystal cell, AC afterimage measurement and contrast measurement were performed according to the above-described evaluation method "AC afterimage measurement·contrast measurement". As a result, ΔB was 1.3% and CR was 3300.

[0293] <VHR Reliability Evaluation> Liquid crystal alignment agent E1 was applied to a glass substrate with IPS electrodes and a glass substrate with column spacers by the spinner method. After application, the substrate was heated at 60°C for 80 seconds to evaporate the solvent, and then the substrate was irradiated with linearly polarized ultraviolet light from a vertical direction through a polarizing plate using a Multilight ML-501C / B manufactured by Ushio Inc. The exposure energy at this time was measured using an ultraviolet integrating light meter UIT-150 (receiver: UVD-S365) manufactured by Ushio Inc., and was 2.0±0.1 J / cm at a wavelength of 365 nm. 2 After that, the substrate was baked at 220° C. for 30 minutes to form a liquid crystal alignment film having a thickness of about 100 nm.

[0294] Next, two substrates on which liquid crystal alignment films were formed were bonded together so that the surfaces on which the liquid crystal alignment films were formed faced each other and a gap for injecting a liquid crystal composition was formed between the facing liquid crystal alignment films. At this time, the substrates were oriented so that the polarization directions of the linearly polarized light irradiated on each liquid crystal alignment film during the photo-alignment treatment were parallel to each other. A negative type liquid crystal composition A having the following composition was injected into the gap between the bonded substrates to prepare a liquid crystal cell (liquid crystal display element) with a cell thickness of 7 μm.

[0295] <Negative Liquid Crystal Composition A> TIFF0007673614000150.tif158113 (Physical properties) Phase transition temperature NI: 75.7°C, dielectric anisotropy Δε: -4.1, refractive index anisotropy Δn: 0.101, viscosity η: 14.5 mPa s.

[0296] Using the liquid crystal cell thus fabricated, a VHR reliability evaluation was carried out according to the aforementioned evaluation method "Evaluation of voltage holding ratio (VHR) reliability." As a result, the VHR degradation rate was -6%.

[0297] [Example 2] to [Example 18], [Comparative Example 1] to [Comparative Example 3] Except for using the varnish shown in Table 4 instead of varnish A1, the same operation as in Example 1 was performed to prepare liquid crystal alignment agents E2 to E18 and F1 to F3. In addition, the additives shown in Table 4 were added to liquid crystal alignment agents E11, E12, and E18 in the weight parts shown in Table 4 relative to the polymer weight in the varnish to prepare liquid crystal alignment agents. Using the prepared liquid crystal alignment agent, the same operation as in Example 1 was performed to measure contrast, measure AC image retention, and evaluate VHR reliability. The results are shown in Table 4 together with the results of Example 1.

[0298] [Table 4] TIFF0007673614000151.tif216134

[0299] In Examples 1 to 18 using the compound represented by formula (1) of the present invention, the contrast value was 3000 or more, and the contrast was excellent. In addition, the value of ΔB was small at 2% or less, and the image retention characteristics were excellent. Furthermore, the VHR decrease rate was small, and a liquid crystal display element with high VHR reliability was obtained. On the other hand, in Comparative Example 1 and Comparative Example 3, the compounds used (compound represented by formula (AN-1-2, m=6) and compound represented by formula (AN-1-3)) were not aromatic tetracarboxylic acids in which dicarboxylic anhydrides were directly bonded to the aromatic ring, so the VHR decrease rate was suppressed, but a liquid crystal display element with good contrast and ΔB was not obtained. In Comparative Example 2, the contrast and ΔB were good, but the VHR decrease rate was large because the compound used (compound represented by formula (AN-3-2)) was an aromatic tetracarboxylic acid in which dicarboxylic anhydrides were directly bonded to the aromatic ring.

[0300] [Example 19] to [Example 36], [Comparative Example 4] to [Comparative Example 5] Except for using the varnish and additives shown in Table 5 instead of varnish A1, the same operation as in Example 1 was performed to prepare liquid crystal alignment agents E19 to 36 and F4 to F5. Using the prepared liquid crystal alignment agents, the same operation as in Example 1 was performed to measure contrast, measure AC image retention, and evaluate VHR reliability. The results are shown in Table 5.

[0301] [Table 5] TIFF0007673614000152.tif206134

[0302] In Examples 19 to 36, in which a block polymer using the compound represented by formula (1) of the present invention was used, the contrast value was 3000 or more, and excellent contrast was shown. In addition, the value of ΔB was small at 2% or less, and excellent afterimage characteristics were shown. Furthermore, the VHR decrease rate was small, and a liquid crystal display element with high VHR reliability was obtained. On the other hand, in Comparative Example 4, since the compound used (compound represented by formula (AN-1-2, m=6)) is not an aromatic tetracarboxylic acid in which a dicarboxylic anhydride is directly bonded to an aromatic ring, the VHR decrease rate was suppressed, but a liquid crystal display element with good contrast and ΔB was not obtained. In Comparative Example 5, the contrast and ΔB were good, but the VHR decrease rate was large because the compound used (compound represented by formula (AN-3-2)) is an aromatic tetracarboxylic acid in which a dicarboxylic anhydride is directly bonded to an aromatic ring.

[0303] [Example 37] Varnish A1 and varnish B1 were blended in a weight ratio of 3:7, and then diluted with an NMP·BC mixed solution (NMP / BC=7 / 3 weight ratio) to a polymer concentration of 4 wt%, followed by stirring to prepare liquid crystal alignment agent E37. Using the liquid crystal alignment agent E37, the same operations as in Example 1 were carried out to measure contrast, measure AC image retention, and evaluate VHR reliability.

[0304] [Example 38] to [Example 57], [Comparative Example 6] to [Comparative Example 7] Instead of varnish A1 and varnish B1, the varnishes and additives shown in Table 6 were used, and the blend ratios were changed to those shown in Table 6. The liquid crystal alignment agents E38 to E57 and F6 to F7 were prepared in the same manner as in Example 37. Using the prepared liquid crystal alignment agents, the contrast was measured, AC image retention was measured, and VHR reliability was evaluated in the same manner as in Example 1. The varnishes used, the blend ratios, and the results are shown in Table 6 together with Example 37.

[0305] [Table 6] TIFF0007673614000153.tif235153

[0306] In Examples 37 to 57, in which a blend type liquid crystal alignment agent using the compound represented by formula (1) of the present invention was used, the contrast value was 3000 or more, and excellent contrast was shown. In addition, the value of ΔB was small at 3% or less, and excellent afterimage characteristics were shown. Furthermore, the VHR decrease rate was small, and a liquid crystal display element with high VHR reliability was obtained. On the other hand, in Comparative Example 6, since the compound used (compound represented by formula (AN-1-2, m = 6)) is not an aromatic tetracarboxylic acid in which a dicarboxylic anhydride is directly bonded to an aromatic ring, the VHR decrease rate was suppressed, but a liquid crystal display element with good contrast and ΔB was not obtained. In Comparative Example 7, the contrast and ΔB were good, but the VHR decrease rate was large because the compound used (compound represented by formula (AN-3-2)) is an aromatic tetracarboxylic acid in which a dicarboxylic anhydride is directly bonded to an aromatic ring. [Industrial Applicability]

[0307] By using a liquid crystal alignment film formed by using the liquid crystal alignment agent of the present invention, a liquid crystal display element can be obtained that has good contrast and afterimage characteristics, and maintains a high voltage retention rate and does not deteriorate in display quality even when exposed to strong light for a long period of time. The liquid crystal alignment agent of the present invention can be suitably applied to a horizontal electric field type liquid crystal display element. In addition, by using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film with high anisotropy can be obtained, and it can be used as an optical compensation material, etc.

Claims

1. A liquid crystal alignment agent comprising a polymer, at least one of the polymers being a polymer obtained by reacting tetracarboxylic dianhydrides with diamines, the tetracarboxylic dianhydrides comprising at least one selected from the group consisting of a compound represented by formula (1) and a compound derived therefrom. In formula (1), -X- is independently a single bond, -O-, -S-, or -NR １ - and R １ represents hydrogen or an alkyl group having 1 to 4 carbon atoms, n is independently an integer of 1 to 5, and m is an integer of 1 to 3, and a group that is not fixedly bonded to any of the carbon atoms constituting the ring can be bonded to any available carbon atom in the ring.

2. The liquid crystal aligning agent according to claim 1, wherein the compound represented by formula (1) is at least one selected from the group consisting of compounds represented by formulas (2) to (4). In formulas (2) to (4), m is an integer of 1 to 3, and in formula (4), n is independently an integer of 2 to 5.

3. The liquid crystal aligning agent according to claim 1 or 2, wherein the raw material composition used as a raw material for the polymer obtained by reacting the tetracarboxylic dianhydrides with the diamines contains at least one selected from the group consisting of the compound represented by formula (1) and its derivative compound, and a compound having a photoreactive structure.

4. The liquid crystal aligning agent according to claim 3 , wherein the compound having a photoreactive structure is a compound having a photodecomposition structure, a compound having a photoisomerization structure, or a compound having a photodimerization structure.

5. The liquid crystal aligning agent according to claim 4, wherein the compound having a photoisomerizable structure is a compound represented by the following formula (V-2): In formula (V-2), X is an alkylene group having 1 to 12 carbon atoms, and the alkylene group is —(CH ２ ) ２ one or more non-adjacent -'s may be replaced with -O- or -NH-; R ａ and R ｂ are each independently a hydrogen atom, -CH ３ , -OCH ３ , -CF ３ , -F, -COOCH ３ or a monovalent group represented by formula (P1-1) or formula (P1-2), R ｃ are each independently a hydrogen atom, -CH ３ , -OCH ３ , -CF ３ , -F, or a monovalent group represented by formula (P1-1) or formula (P1-2), j is 0 or 1, and a to c each independently represent an integer of 0 to 2, In formula (P1-1) and formula (P1-2), R ｄ , R ｅ and R ｆ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkanoyl group, a substituted or unsubstituted alkoxycarbonyl group, or a substituted or unsubstituted arylcarbonyl group; R ｄ , R ｅ and R ｆ may be the same or different, * represents the bonding position to the benzene ring in formula (V-2), In formula (V-2), a group that is not fixed to any of the carbon atoms constituting the ring indicates that it can be bonded to any available carbon atom in the ring.

6. A liquid crystal alignment film formed from the liquid crystal aligning agent according to any one of claims 1 to 5.

7. A liquid crystal display device comprising the liquid crystal alignment film according to claim 6.

8. A method for producing a liquid crystal alignment film, comprising the steps of: applying the liquid crystal aligning agent according to any one of claims 1 to 5 to a substrate; and irradiating the coating with polarized ultraviolet light.

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