Method for manufacturing liquid crystal alignment film and method for manufacturing liquid crystal display element

Abstract

Provided are: a photo-alignment material which, using ultraviolet light having a wavelength of 254 nm, which is most widely used in the field of manufacturing liquid crystal display elements, can achieve good photo-alignment even when fired at low temperatures of 200 DEG C or less; more specifically, the present invention provides a method for producing a liquid crystal alignment film, which obtains a liquid crystal alignment film by: a step for exposing an organic film having a polymer (P) to polarized ultraviolet light having a wavelength of 254 nm (the proportion of 254 nm light is 90% or more with respect to the total amount of light having wavelengths of 254 nm, 313 nm, and 365 nm contained in the polarized ultraviolet light); the polymer (P) is obtained by polymerizing a polymerizable unsaturated hydrocarbon group in a monomer component containing a polymerizable compound represented by formula (1); and a step for heating at the liquid crystallinity expression temperature of the polymer. (In the formula, each parameter is as defined in the description. ).

Description

Technical Field

[0001] This invention relates to a method for manufacturing a liquid crystal alignment film using a specific polymer composition, and a method for manufacturing a substrate having the alignment film. Furthermore, this invention relates to a novel method for manufacturing liquid crystal display elements with excellent alignment stability. Background Technology

[0002] Liquid crystal display (LCD) elements are known as lightweight, thin, and low-power display devices, and have seen significant development in recent years, particularly in applications such as large-format televisions. An LCD element, for example, is constructed by sandwiching a liquid crystal layer between a pair of transparent substrates equipped with electrodes. Furthermore, in LCD elements, an organic film containing organic materials is used as a liquid crystal alignment film to ensure that the liquid crystal is aligned in a desired state between the substrates.

[0003] In other words, the liquid crystal alignment film is a component of a liquid crystal display element, formed on the surface of the substrate holding the liquid crystal that is in contact with it, and plays the role of aligning the liquid crystal in a certain direction between the substrates. Furthermore, in addition to aligning the liquid crystal in a certain direction, such as a direction parallel to the substrate, the liquid crystal alignment film sometimes also requires the ability to control the pretilt angle of the liquid crystal. This ability of the liquid crystal alignment film to control the alignment of the liquid crystal (hereinafter referred to as alignment control capability) is provided by performing an alignment process on the organic film constituting the liquid crystal alignment film.

[0004] As an alignment treatment method for liquid crystal alignment films that impart alignment control capabilities, the rubbing method has long been known. The rubbing method involves rubbing the surface of an organic film such as polyvinyl alcohol, polyamide, or polyimide on a substrate in a specific direction using a cloth such as cotton, nylon, or polyester, causing the liquid crystal to align in the rubbing direction. This rubbing method can easily achieve a relatively stable alignment state of the liquid crystal, and therefore is used in existing liquid crystal display element manufacturing processes. Furthermore, as for the organic film used for liquid crystal alignment films, polyimide-based organic films with excellent heat resistance, reliability, and electrical properties are primarily selected.

[0005] However, the rubbing method of wiping the surface of liquid crystal alignment films containing polyimide or the like has the problem of generating dust or static electricity. In addition, due to the high precision of liquid crystal display elements in recent years, or the unevenness caused by the electrodes on the corresponding substrate or the switching active elements for driving the liquid crystal, it is not possible to use a cloth to wipe the surface of the liquid crystal alignment film evenly, and sometimes it is not possible to achieve uniform liquid crystal alignment.

[0006] Therefore, photoalignment is being actively researched as another alignment treatment method for liquid crystal alignment films that do not involve friction.

[0007] Optical alignment methods include various approaches that use linearly polarized or collimated light to create anisotropy within the organic film constituting the liquid crystal alignment film, thereby aligning the liquid crystal according to this anisotropy.

[0008] As a primary method of photoalignment, decomposition-type photoalignment is known. For example, polarized ultraviolet light is irradiated onto a polyimide film, and anisotropic decomposition occurs due to the polarization direction dependence of ultraviolet absorption by the molecular structure. Then, the undecomposed and residual polyimide is used to align the liquid crystal (see Patent Document 1).

[0009] In addition, photocrosslinking-type photoorientation methods are also known. For example, polyvinyl cinnamate is used, and polarized ultraviolet light is irradiated, causing a dimerization reaction (crosslinking reaction) at the double bond portion of the two side chains parallel to the polarized light. Furthermore, a pretilt angle is exhibited by irradiating polarized ultraviolet light in an inclined direction (see Non-Patent Document 1). In addition, when using a side-chain type polymer with coumarin in the side chains, polarized ultraviolet light is irradiated, and a photocrosslinking reaction occurs at the coumarin portion of the side chains parallel to the polarized light, causing the liquid crystal to be oriented in a direction parallel to the polarized light direction (see Non-Patent Document 2).

[0010] As illustrated in the examples above, the alignment process for liquid crystal alignment films using photo-alignment eliminates the need for friction and eliminates concerns about dust or static electricity. Furthermore, it allows for alignment processing on substrates with uneven surfaces of liquid crystal display elements, making it a suitable method for industrial production processes. Moreover, photo-alignment allows for control of the alignment direction using ultraviolet light, thus enabling the formation of multiple regions with different alignment directions within a pixel (alignment segmentation) to compensate for viewing angle dependence.

[0011] On the other hand, the liquid crystal alignment film also plays the role of imparting a certain tilt angle (pretilt angle) to the liquid crystal. Imparting the pretilt angle has become an important technical issue in the development of liquid crystal alignment films (see Patent Documents 1-4).

[0012] In liquid crystal display elements used in LCD TVs, LCD monitors, and LCD displays for portable devices, polyimide-based liquid crystal alignment films are most commonly used due to their superior productivity and excellent chemical and thermal durability. These polyimide-based liquid crystal alignment films are manufactured by coating a solution of polyimide, or a solution of polyamic acid as a polyimide precursor, onto a substrate, and then firing it at a temperature of approximately 200°C to 250°C.

[0013] In recent years, in order to make liquid crystal display elements lighter and more flexible, based on the requirements of liquid crystal alignment films corresponding to plastic substrates, the requirements of heat resistance from color filters, and the requirements of energy cost reduction, polyimide-based liquid crystal alignment film materials that can be sintered at low temperatures below 200°C have been proposed (for example, see Patent Document 5).

[0014] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 02-223916 Patent Document 2: Japanese Patent Application Publication No. 04-281427 Patent Document 3: Japanese Patent Application Publication No. 05-043687 Patent Document 4: Japanese Patent Application Publication No. 10-333153 Patent Document 5: Japanese Patent Application Publication No. 5-158047 Patent Document 6: International Publication No. 2013 / 081066 Patent Document 7: International Publication No. 2012 / 085048 Non-patent literature Non-patent literature 1: S. Kobayashi et al., Journal of Photopolymer Science and Technology, Vol.8, No.2, pp25-262 (1995). Non-patent literature 2: M. Shadt et al., Nature. Vol. 381, 212 (1996). Summary of the Invention The technical problem that the invention aims to solve As mentioned above, it is known that during the low-temperature sintering process of liquid crystal alignment films, the alignment properties, reliability, and mechanical strength of polyimide-based liquid crystal alignment films deteriorate significantly. This is especially true for polyimide liquid crystal alignment films using photo-alignment methods, where maintaining liquid crystal alignment during low-temperature sintering is extremely difficult from the perspective of ensuring alignment. This is because the thermal ring-closing rate of polyamic acid is not fully realized during sintering below 180°C. Furthermore, the glass transition temperatures (Tg) of polyamic acid and polyimide are typically above 200°C, making it impossible to induce material movement during low-temperature sintering.

[0015] It is known that liquid crystal polymers obtained from monomers with cinnamic acid or cinnamic ester structures in their side chains exhibit good photoorientation even during low-temperature calcination (Patent Document 6). They can be photooriented by exposure to ultraviolet light with wavelengths of 313–365 nm, corresponding to the absorption from cinnamic acid. On the other hand, the absorption band of cinnamic acid extends into the visible light region, thus posing a significant technical challenge regarding lightfastness.

[0016] To improve lightfastness, a method has been proposed to orient cinnamic acid and cinnamic esters by fully photodimerizing them (Patent Document 7). However, in sintered films containing side-chain polymers containing cinnamic esters, irradiation with 1–5 J / cm of 313 nm ultraviolet light is required. 2 Such situations often require prolonged and extensive exposure to ultraviolet radiation.

[0017] In the actual manufacturing of liquid crystal display elements, the photo-alignment method, which utilizes photodecomposition induced by exposure to 254nm polarized ultraviolet light, is mainly used. However, the practical application of materials capable of alignment via wavelengths of 313–365nm requires additional investment in equipment such as polarization filters and light sources. Furthermore, it is believed that the aforementioned materials containing cinnamic acid do not achieve good photo-alignment in 254nm ultraviolet light, and even if they do, the exposure margin is very narrow, leading to a deterioration in yield.

[0018] Therefore, in liquid crystal alignment materials that can be sintered at low temperatures, there is a requirement for efficient and stable liquid crystal alignment processing, and for liquid crystal alignment films and liquid crystal alignment agents that can efficiently impart high alignment control to liquid crystal alignment films.

[0019] The purpose of the liquid crystal alignment agent of the present invention is to provide a photoalignment material and a process thereof, wherein the photoalignment material uses ultraviolet light with a wavelength of 254nm, which is most widely used in the manufacturing of liquid crystal display elements, and can obtain good photoalignment even in low-temperature firing below 200°C.

[0020] In addition to the above, photo-alignment materials with good light resistance and mechanical strength can also be provided. Therefore, photo-alignment films can be obtained with good yield through low-temperature sintering without significant changes to the existing production line.

[0021] Technical solutions for solving technical problems In order to solve the above-mentioned technical problems, the inventors conducted in-depth research and found that the above-mentioned technical issues could be resolved, thus completing the present invention with the following main points.

[0022] [1] A method for manufacturing a liquid crystal alignment film, wherein the liquid crystal alignment film is obtained by the following steps: exposing an organic film having a polymer (P) to polarized ultraviolet light of a wavelength of 254 nm (the proportion of light of 254 nm is 90% or more relative to the total amount of light of wavelengths of 254 nm, 313 nm and 365 nm contained in the polarized ultraviolet light), wherein the polymer (P) is obtained by polymerization of a polymeric unsaturated hydrocarbon group in a monomer component comprising a polymeric compound represented by the following formula (1); and heating at the liquid crystal performance temperature of the polymer.

[0023] [Chemistry 1] (In the formula, n is 0, 1, 2 or 3. m is 1 or 2.)

[0024] L is a single bond, an alkylene group having 1 to 12 carbon atoms, or a divalent linking group consisting of one or more -CH2- atoms of an alkylene group having 1 to 12 carbon atoms, each independently replaced by -O-, -S-, -C(=O)-O-, or -OC(=O)-, wherein some or all of the hydrogen atoms of the alkylene group and the divalent linking group may be replaced by halogen atoms.

[0025] A can be a single bond, -O-, -CH2-, -C(=O)-O-, -OC(=O)-, -C(=O)-NH-, or -NH-C(=O)-.

[0026] Y is phenylene or naphthylene, and some or all of the hydrogen atoms of the phenylene and naphthylene may be replaced by a cyano group, a halogen atom, an alkyl group with 1 to 5 carbon atoms, an alkyl carbonyl group with 2 to 6 carbon atoms, or an alkoxy group with 1 to 5 carbon atoms.

[0027] Q is a single bond, a phenylene group, or a divalent alicyclic hydrocarbon group with 5 to 8 carbon atoms. Some or all of the hydrogen atoms of the phenylene group may be replaced by a cyano group, a halogen atom, an alkyl group with 1 to 5 carbon atoms, an alkyl carbonyl group with 2 to 6 carbon atoms, or an alkoxy group with 1 to 5 carbon atoms.

[0028] X is a single bond, -O-, -C(=O)-O-, -OC(=O)-, -N=N-, -CH=CH-, -C≡C-, -CH=CH-C(=O)-O-, or -OC(=O)-CH=CH-.

[0029] When the number of L, A, Y, Q, and X is 2 or more, each L, A, Y, Q, and X can be the same or different from each other.

[0030] M is a polymerizable unsaturated hydrocarbon group.

[0031] [2] According to the manufacturing method described in [1] above, the polymer (P) is a polymer composed of liquid crystal units that have a large absorption peak only in the wavelength region below 330 nm.

[0032] [3] According to the manufacturing method described in [1] or [2] above, the polymer (P) is a polymer that exhibits nematic liquid crystal properties or smectic liquid crystal properties in a temperature range of 90 to 200°C.

[0033] [4] The manufacturing method according to any one of [1] to [3] above, wherein M in the above formula (1) is represented by any one of the following.

[0034] [Chemistry 2] (In the formula, R1 and R2 each independently represent a hydrogen atom or a straight-chain or branched alkyl group with 1 to 12 carbon atoms, and E, T and G each independently represent an oxygen atom or a sulfur atom.) , 1 and 2 Indicates the bonding site. 1 and 2 Any of the atoms in the group can be replaced by a hydrogen atom or a straight-chain or branched alkyl group having 1 to 12 carbon atoms.

[0035] [5] The manufacturing method according to any one of [1] to [4] above, wherein the liquid crystal alignment agent used to form the above organic film also comprises a compound having an alkoxysilyl group and a urea structure having substituted at the 1- and 3-positions.

[0036] [6] A method for manufacturing a liquid crystal display element, comprising: a step of manufacturing a substrate having a liquid crystal alignment film obtained by any one of the manufacturing methods described in [1] to [5] above.

[0037] Invention Effects Using the liquid crystal alignment agent obtained by the manufacturing method of the present invention, good photoalignment can be obtained even in low-temperature firing below 180°C, and good alignment stability and good mechanical strength can also be obtained. Furthermore, 254nm light, which is most widely used in the manufacture of liquid crystal display elements, can be used, and the necessary exposure amount is also sufficiently low, thus providing a liquid crystal alignment film with low process load and good processability.

[0038] In this instruction manual, This represents a bonding bond. Attached Figure Description

[0039] Figure 1 This is a schematic cross-sectional view illustrating an example of the transverse electric field liquid crystal display element of the present invention.

[0040] Figure 2 This is a schematic cross-sectional view illustrating other examples of the transverse electric field liquid crystal display element of the present invention. Detailed Implementation

[0041] (Strong anchoring) In this invention, "strong anchoring" refers to the ability to uniaxially constrain the orientation of liquid crystal molecules in the azimuth or polar direction, maintaining the orientation of the liquid crystal even when external energy is applied, or restoring the liquid crystal molecules to their original position even if their orientation changes. In this invention, strong anchoring refers to an azimuth anchoring strength (A2) greater than 10. -4 [J / m 2 [The situation is as follows].

[0042] (Strongly anchored orientation film) In this invention, a "strongly anchored alignment film" refers to a film that forms a strongly anchored state through contact with liquid crystal. It is a liquid crystal alignment film capable of uniformly aligning liquid crystals in a uniaxial direction and maintaining the aligned liquid crystals with sufficiently strong interfacial anchoring energy. The strongly anchored liquid crystal alignment agents used in this invention include two types: those with orientation-limiting forces that uniaxially align liquid crystals in the horizontal direction and those with orientation-limiting forces that uniaxially align liquid crystals in the azimuth direction. The strongly anchored liquid crystal alignment film with horizontal orientation-limiting forces is obtained by subjecting a cured film, obtained by coating on a substrate, drying, and firing, to a friction treatment or photoalignment treatment. Furthermore, the strongly anchored liquid crystal alignment film with orientation-limiting forces in the azimuth direction is obtained by subjecting a cured film, obtained by coating on a substrate, drying, and firing, to a photoalignment treatment.

[0043] (Strongly anchored liquid crystal display element) Two strongly anchored alignment films, as defined above, are coated onto a substrate with electrodes and bonded together in pairs, thereby enabling the fabrication of strongly anchored liquid crystal display elements.

[0044] (Polymer(P)) The strongly anchored liquid crystal alignment agent with horizontal orientation constraint obtained by the manufacturing method of the present invention is a strongly anchored liquid crystal alignment agent containing a side chain structure (hereinafter also referred to as a photosensitive side chain) that undergoes photoreaction or photodecomposition with ultraviolet light absorbing a wavelength of 254 nm, and a side chain polymer (hereinafter also simply referred to as a liquid crystal side chain polymer) that can exhibit nematic liquid crystallization, smectic liquid crystallization, or both upon heating. The coating film obtained from the above polymer is also a film containing a side chain polymer with both photosensitive and liquid crystallization properties. Instead of rubbing, the coating film undergoes orientation treatment by polarized light irradiation. Then, after polarized light irradiation, the side chain polymer film is heated to obtain a strongly anchored liquid crystal alignment film with horizontal orientation constraint. At this time, the slight anisotropy exhibited by polarized light irradiation becomes the driving force, and the side chain polymer itself effectively re-orients through self-organization. As a result, highly efficient orientation treatment is achieved as a strongly anchored liquid crystal alignment film, and a strongly anchored liquid crystal alignment film endowed with high optical anisotropy can be obtained.

[0045] In this invention, photoreactivity refers to the changes in the complex chemical structures induced by absorbing ultraviolet light with a wavelength of 254 nm, such as photodimerization, photoisomerization, and photodecomposition, thereby exhibiting axial selectivity in these structures.

[0046] The aforementioned side-chain polymers are side-chain polymers having photosensitive side chains that undergo photoreaction at a specified wavelength, and exhibiting nematic or smectic liquid crystal properties at the inherent liquid crystal performance temperature of the polymer. Preferably, the aforementioned side-chain polymers are polymers that have a maximum absorption peak only in the wavelength region below 330 nm, react or photodecompose under ultraviolet light in the wavelength range of 200–330 nm, more preferably 220–300 nm, and exhibit liquid crystal properties in the temperature range of 50–300 °C, more preferably 90–200 °C.

[0047] The side chain structure of the above-mentioned side-chain polymer is preferred because the orientation of the liquid crystal is stable when it has rigid liquid crystal building blocks. However, in this case, the inherent liquid crystal performance temperature of the polymer will be higher. Therefore, the rigidity of the side chain can be selected within an appropriate range.

[0048] The polymer (P) forming the strongly anchored liquid crystal alignment agent with horizontal orientation restriction force of the present invention mainly plays the role of highly uniaxially restricting the orientation of liquid crystal molecules.

[0049] The structure of the polymerizable compound that serves as the raw material for the aforementioned side-chain type polymer with photoreactive side chains is preferably the structure shown in formula (1) below. It should be noted that, from the viewpoint of solubility in solvents and low-temperature sintering, the number of benzene rings in each photosensitive side chain is preferably three or less.

[0050] [Chemistry 3] (In the formula, n is 0, 1, 2 or 3. m is 1 or 2.)

[0051] L is a single bond, an alkylene group having 1 to 12 carbon atoms, or a divalent linking group consisting of one or more -CH2- atoms of an alkylene group having 1 to 12 carbon atoms, each independently replaced by -O-, -S-, -C(=O)-O-, or -OC(=O)-, wherein some or all of the hydrogen atoms of the alkylene group and the divalent linking group may be replaced by halogen atoms.

[0052] A can be a single bond, -O-, -CH2-, -C(=O)-O-, -OC(=O)-, -C(=O)-NH-, or -NH-C(=O)-.

[0053] Y is phenylene or naphthylene, and some or all of the hydrogen atoms of the phenylene and naphthylene may be replaced by a cyano group, a halogen atom, an alkyl group with 1 to 5 carbon atoms, an alkyl carbonyl group with 2 to 6 carbon atoms, or an alkoxy group with 1 to 5 carbon atoms.

[0054] Q is a single bond, a phenylene group, or a divalent alicyclic hydrocarbon group with 5 to 8 carbon atoms. Some or all of the hydrogen atoms of the phenylene group may be replaced by a cyano group, a halogen atom, an alkyl group with 1 to 5 carbon atoms, an alkyl carbonyl group with 2 to 6 carbon atoms, or an alkoxy group with 1 to 5 carbon atoms.

[0055] X is a single bond, -O-, -C(=O)-O-, -OC(=O)-, -N=N-, -CH=CH-, -C≡C-, -CH=CH-C(=O)-O-, or -OC(=O)-CH=CH-.

[0056] When the number of L, A, Y, Q, and X is 2 or more, each L, A, Y, Q, and X can be the same or different from each other.

[0057] M is a polymerizable unsaturated hydrocarbon group. The aforementioned alkylene groups having 1 to 12 carbon atoms can be any of the following: linear, branched, or cyclic. Specific examples include methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, and decane-1,10-diyl.

[0058] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine.

[0059] The alkyl groups having 1 to 5 carbon atoms can be either straight-chain or branched. Specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, and n-pentyl.

[0060] Specific examples of alkyl carbonyl groups with 2 to 6 carbon atoms include methyl carbonyl (acetyl), ethyl carbonyl, n-propyl carbonyl, n-butyl carbonyl, and n-pentyl carbonyl.

[0061] Specific examples of alkoxy groups with 1 to 5 carbon atoms mentioned above include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, and n-pentoxy.

[0062] Specific examples of the aforementioned divalent alicyclic hydrocarbon groups with 5 to 8 carbon atoms include cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, and cyclooctanediyl.

[0063] The polymerizable unsaturated hydrocarbon group of M in formula (1) above is preferably a structure shown in any of the following. However, it is not limited to these.

[0064] [Chemistry 4] (In the formula, R1 and R2 each independently represent a hydrogen atom or a straight-chain or branched alkyl group with 1 to 12 carbon atoms, and E, T and G each independently represent an oxygen atom or a sulfur atom.) , 1 and 2 Indicates the bonding site. 1 and 2 Any of these can be replaced by a hydrogen atom or a straight-chain or branched alkyl group having 1 to 12 carbon atoms. Examples of straight-chain or branched alkyl groups with 1 to 12 carbon atoms include: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, etc.; isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, sec-pentyl, isohexyl, neohexyl, 4-methylhexyl, 5-methylhexyl, 4,5-dimethylhexyl, 1-ethylhexyl, 2-ethylhexyl, 3-ethylhexyl, 4-ethylhexyl, 2-ethylpentyl, heptane-3-yl, heptane-4-yl, 4-methylhexane-2-yl Branched alkyl groups, including 3-methylhexane-3-yl, 2,3-dimethylpentane-2-yl, 2,4-dimethylpentane-2-yl, 4,4-dimethylpentane-2-yl, 6-methylheptyl, 2-ethylhexyl, octane-2-yl, 6-methylheptane-2-yl, 6-methyloctyl, 3,5,5-trimethylhexyl, nonane-4-yl, 2,6-dimethylheptane-3-yl, 3,6-dimethylheptane-3-yl, 3-ethylheptane-3-yl, 3,7-dimethyloctyl, 6,7-dimethyloctyl, 8-methylnonyl, 3-methylnonane-3-yl, 4-ethyloctane-4-yl, etc.

[0065] As the polymeric compound represented by formula (1) above, the structure shown in any of the following is preferred. However, it is not limited to these.

[0066] [Chemistry 5] From the viewpoint of achieving good liquid crystal orientation, the preferred polymer (P) has a molecular weight of 1,000 to 100,000, more preferably 3,000 to 50,000. It should be noted that this molecular weight is the number-average molecular weight (Mn) converted from polystyrene, as determined by gel permeation chromatography (GPC). Furthermore, the molecular weight distribution PDI (Mw / Mn), expressed as the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) converted from polystyrene as determined by GPC, is preferably 5.0 or less, more preferably 3.0 or less.

[0067] When obtaining the polymer (P), the polymerization method is not particularly limited. Cationic polymerization and anionic polymerization often use alkali metals, metal complexes, or halogen compounds to generate active species. In liquid crystal displays, the incorporation of metal residues and halogen compounds can be a major cause of screen burn-in and display defects. Therefore, it is preferable to use free radical polymerization that minimizes the use of metals and halogen compounds. Examples of living free radical polymerization include living free radical polymerization (NMP) using nitroxide radicals as dormant species, atom transfer radical polymerization (ATRP) using metal complexes, reversible addition-fragmentation chain transfer polymerization (RAFT) using sulfur compounds as dormant species, living free radical polymerization (TERP) using organotellurium compounds, and reversible transfer catalytic polymerization (RTCP) using alkyl iodine compounds as dormant species and phosphorus compounds, alcohols, etc., as catalysts. Preferred polymerization methods include living free radical polymerization such as NMP, RTCP, and RAFT polymerization, with NMP or RAFT polymerization being particularly preferred. Chain transfer polymerization is also preferred.

[0068] When using NMP, examples of polymerization initiators include 2,2′-azobis(isobutyronitrile), 2,2′-azobis(2,4-dimethylpentanonitrile), benzoyl peroxide, 1,1′-bis(tert-butylperoxide)cyclohexane, and hydrogen peroxide. The proportion of the polymerization initiator used is typically 0.000001 to 0.1 moles, preferably 0.00001 to 0.01 moles, relative to 1 mole of the monomer used. Examples of nitroxide radicals include compounds represented by formulas (N-1) to (N-12). The proportion of the nitroxide radical used is typically 0.000001 to 0.1 moles, preferably 0.00001 to 0.01 moles, relative to 1 mole of the monomer used. The reaction temperature in the above polymerization is preferably 20 to 200°C, more preferably 40 to 150°C, and the reaction time is preferably 1 to 168 hours, more preferably 8 to 72 hours.

[0069] [Chemistry 6] In the case of using RTCP, in addition to low-molecular-weight dormant species that help to manifest activity, iodide or hydride catalysts and polymerization initiators are also required to promote the reaction.

[0070] Examples of polymerization initiators used include 2,2′-azobis(isobutyronitrile), 2,2′-azobis(2,4-dimethylpentanonitrile), benzoyl peroxide, 1,1′-bis(tert-butylperoxide)cyclohexane, and hydrogen peroxide. The ratio of the polymerization initiator to 1 mole of the monomer used is typically 0.000001 to 0.1 moles, preferably 0.00001 to 0.01 moles.

[0071] Examples of low-molecular-weight dormant species include compounds represented by formulas (Q-1) to (Q-3). The proportion of the low-molecular-weight dormant species used is typically 0.000001 to 0.1 moles relative to 1 mole of the monomer used, preferably 0.00001 to 0.01 moles.

[0072] [Chemistry 7] Examples of iodide catalysts include compounds represented by formulas (P-1) to (P-4). The proportion of iodide catalyst used is typically 0.000001 to 0.1 moles relative to 1 mole of the monomer used, preferably 0.00001 to 0.01 moles.

[0073] [Chemistry 8] Examples of hydride catalysts include compounds represented by formulas (O-1) to (O-6). The proportion of the hydride catalyst used is 0.000001 to 0.1 moles, preferably 0.00001 to 0.01 moles, relative to 1 mole of the monomer used. Typically, the reaction temperature in the above polymerization is preferably 20 to 200°C, more preferably 40 to 150°C, and the reaction time is preferably 1 to 168 hours, more preferably 8 to 72 hours.

[0074] [Chemistry 9] In the case of RAFT polymerization, examples of polymerization initiators used include 2,2′-azobis(isobutyronitrile), 2,2′-azobis(2,4-dimethylpentanonitrile), benzoyl peroxide, 1,1′-bis(tert-butylperoxide)cyclohexane, and hydrogen peroxide. The proportion of the polymerization initiator used is typically 0.000001 to 0.1 moles relative to 1 mole of the monomer used, preferably 0.00001 to 0.01 moles. As chain transfer agents (RAFT agents), trithiocarbonates, dithiobenzoates, dithiocarbamates, and xanthates are preferred; specific examples include compounds shown in formulas (R-1) to (R-24). The proportion of the chain transfer agent used is typically 0.000001 to 0.1 moles relative to 1 mole of the monomer used, preferably 0.00001 to 0.01 moles. The reaction temperature in the above polymerization is preferably 20-200°C, more preferably 40-150°C, and the reaction time is preferably 1-168 hours, more preferably 8-72 hours.

[0075] [Chemistry 10] The active radical nature of RAFT polymerization is due to the existence of compounds that can reversibly inactivate the growing free radical species, as most of the active chains are dormant, resulting in a rapid equilibrium between active and dormant chains.

[0076] By using RAFT polymerization, it is possible to control the polymer end, highly control the molecular weight, and control the molecular weight distribution.

[0077] In order to precisely synthesize functional polymers using RAFT polymerization, the reactivity of the monomers needs to be considered when selecting appropriate chain transfer agents.

[0078] In RAFT polymerization, the polymer termini can be controlled by thermally and chemically modifying the RAFT termini present at the growth ends. In the case of thermal modification, heating above the thermal decomposition temperature of the RAFT agent allows the termini to be modified into unsaturated hydrocarbon groups. Furthermore, in the case of chemical modification, contact with primary or secondary amines allows for ammonolysis, resulting in the modification of the termini into thiol bonds. Moreover, contact with new monomers and free radical generators allows for the incorporation of new block segments at the termini.

[0079] In RAFT polymerization, the molecular weight can be controlled using the following formula (eq.1). Specifically, the number-average molecular weight (Mn) varies linearly with the ratio of the molar concentration of the monomer to the molar concentration of the chain transfer agent, thus allowing for molecular weight control.

[0080] [Number 1] (In the above formula (eq.1), M) n(theor) [Monomer]0 represents the molecular weight of the polymer, [Monomer]0 represents the molar concentration of the monomer, [CTA]0 represents the molar concentration of the chain transfer agent, M monomer The expression represents the molecular weight of the monomer, conv. represents the polymerization conversion rate, and M... CTA This indicates the molecular weight of the chain transfer agent. Alternatively, if the polymer obtained by the above polymerization is dissolved in the reaction solution, the reaction solution can be directly used for the preparation of the liquid crystal alignment agent, or the polymer contained in the reaction solution can be separated and used for the preparation of the liquid crystal alignment agent.

[0081] As polymerization initiators for free radical polymerization, known compounds such as free radical polymerization initiators (free radical thermal polymerization initiators, free radical photopolymerization initiators) and reversible addition-fragmentation chain transfer (RAFT) polymerization reagents can be used.

[0082] In the case of chain transfer polymerization, examples of polymerization initiators used include 2,2′-azobis(isobutyronitrile), 2,2′-azobis(2,4-dimethylpentanonitrile), benzoyl peroxide, 1,1′-bis(tert-butylperoxide)cyclohexane, and hydrogen peroxide. The proportion of the polymerization initiator used is typically 0.000001 to 0.1 moles relative to 1 mole of the monomer used, preferably 0.00001 to 0.01 moles. Thiols are preferably used as chain transfer agents; specific examples include compounds shown in formulas (S-1) to (S-16). The proportion of the chain transfer agent used is typically 0.000001 to 0.1 moles relative to 1 mole of the monomer used, preferably 0.00001 to 0.01 moles. The reaction temperature in the above polymerization is preferably 20-200°C, more preferably 40-150°C, and the reaction time is preferably 1-168 hours, more preferably 8-72 hours.

[0083] [Chemistry 11] (In formulas (S-1) to (S-16), Me represents methyl and Et represents ethyl.) By using chain transfer polymerization, it is possible to control the polymer end, molecular weight, and molecular weight distribution.

[0084] In chain transfer polymerization, polymers are obtained through a competitive reaction between chain transfer and growth. The molecular weight and molecular weight distribution of the polymer obtained by chain transfer polymerization are determined by the chain transfer constant (Cs), which is the quotient of the chain transfer rate constant (kc) and the growth rate constant (kp). Typically, chain transfer polymerization can produce compositions with Cs ranging from 1 to 60, and the types of monomers, chain transfer agents, and their proper combination are important.

[0085] The chain transfer constant (Cs) varies greatly depending on the type of monomer and chain transfer agent used, so it needs to be selected correctly.

[0086] Free radical thermal polymerization initiators are compounds that generate free radicals by heating to temperatures above their decomposition temperature. Examples of such free radical thermal polymerization initiators include: peroxide ketones (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), peroxide diacyls (acetyl peroxide, benzoyl peroxide, etc.), hydroperoxides (hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, etc.), dialkyl peroxides (di-tert-butyl peroxide, dicumyl peroxide, dilauryl peroxide, etc.), peroxide ketals (dibutyl peroxide cyclohexane, etc.), peroxide alkyl esters (tert-butyl peroxyneodecanate, tert-butyl peroxynepentanoate, tert-amyl peroxy-2-ethylcyclohexane, etc.), persulfates (potassium persulfate, sodium persulfate, ammonium persulfate, etc.), and azo compounds (azobisisobutyronitrile, 2,2′-bis(2-hydroxyethyl)azobisisobutyronitrile, etc.). Free radical thermal polymerization initiators can be used alone or in combination of two or more.

[0087] There are no particular limitations on free radical photopolymerization initiators, as long as they are compounds that initiate free radical polymerization through light irradiation. Examples of such free radical photopolymerization initiators include: benzophenone, milchone, 4,4′-bis(diethylamino)benzophenone, xanthonone, thioxanthonone, isopropyl xanthonone, 2,4-diethylthioxanthonone, 2-ethylanthraquinone, acetophenone, 2-hydroxy-2-methylphenylacetone, 2-hydroxy-2-methyl-4′-isopropylphenylacetone, 1-hydroxycyclohexylphenyl ketone, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1-(4-)-phenylacetophenone, etc. -morpholinophenyl)-1-butanone, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 4,4′-bis(tert-butylperoxycarbonyl)benzophenone, 3,4,4′-tris(tert-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-(4′-methoxystyryl)-4,6-bis(trichloromethyl)-triazine, 2-(3′,4′-dimethoxystyryl)-4,6-bis(trichloromethyl)-triazine, 2-(2′,4′-dimethoxystyryl)-4,6-bis(trichloromethyl)-triazine, 2-(2′-methoxystyryl)-4,6-bis(trichloromethyl)- Triazine, 2-(4′-pentoxystyryl)-4,6-bis(trichloromethyl)-triazine, 4-[p-N,N-bis(ethoxycarbonylmethyl)]-2,6-bis(trichloromethyl)-triazine, 1,3-bis(trichloromethyl)-5-(2′-chlorophenyl)-triazine, 1,3-bis(trichloromethyl)-5-(4′-methoxyphenyl)-triazine, 2-(p-dimethylaminostyryl)benzoxazole, 2-(p-dimethylaminostyryl)benzothiazole, 2-mercaptobenzothiazole, 3,3′-carbonylbis(7-diethylaminocoumarin), 2-(o-chlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole, 2,2′ -Bis(2-chlorophenyl)-4,4′,5,5′-tetra(4-ethoxycarbonylphenyl)-1,2′-biimidazole, 2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis(2,4-dibromophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis(2,4,6-trichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole, 3-(2-methyl-2-dimethylaminopropionyl)carbazole, 3,6-bis(2-methyl-2-morpholinopropionyl)-9-n-dodecylcarbazole, 1-hydroxycyclohexylphenyl ketone, bis( η5-2,4-Cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrolo-1-yl)-phenyl)titanium, 3,3′,4,4′-tetra(tert-butylperoxycarbonyl)benzophenone, 3,3′,4,4′-tetra(tert-hexylperoxycarbonyl)benzophenone, 3,3′-bis(methoxycarbonyl)-4,4′-bis(tert-butylperoxycarbonyl)benzophenone, 3,4′-bis (Methoxycarbonyl)-4,3′-bis(tert-butylperoxycarbonyl)benzophenone, 4,4′-bis(methoxycarbonyl)-3,3′-bis(tert-butylperoxycarbonyl)benzophenone, 2-(3-methyl-3H-benzothiazol-2-ylidene)-1-naphth-2-yl-ethyl ketone, 2-(3-methyl-1,3-benzothiazol-2(3H)-ylidene)-1-(2-benzoyl)ethyl ketone, etc. Free radical photopolymerization initiators can be used alone or in combination of two or more.

[0088] As an organic solvent used in the synthesis of polymer (P), any organic solvent that does not chemically react with the compounds constituting the polymer and does not capture free radicals is acceptable. Examples include: N,N-dimethylformamide, N,N-diethylformamide, N,N-dibutylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dipropylacetamide, N,N-dimethylpropionamide, N,N-diethylpropionamide, 3-methoxy-N,N-dimethylpropionamide, N-methylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolinone, N-methyl- ε -Caprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethylphosphoramide, γ-Butyl lactone, isopropanol, methoxymethylpentanol, dipentene, ethylpentyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isopentyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, butyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), propylene glycol, propylene glycol monoacetate, propylene glycol Monomethyl ether, propylene glycol monobutyl ether, propylene glycol tert-butyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol Diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, 1,4-dioxane, n-hexane, n-pentane, n-octane, cyclohexane, 2-ethyl-1-hexanol, benzene, xylene, toluene, ethylbenzene, isopropylbenzene, tert-butylbenzene, tetrahydrofuran, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl... Ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diethylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, 3-ethoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-Dimethylpropionamide, Propyl pyruvate, Butyl pyruvate, Amyl pyruvate, Hexyl pyruvate, 2-Ethylhexyl pyruvate, Methyl acetoacetate, Ethyl acetoacetate, Propyl acetoacetate, Butyl acetoacetate, Amyl acetoacetate, Hexyl acetoacetate, 2-Ethylhexyl acetoacetate, Methyl acetoacetate, Ethyl acetoacetate, Propyl acetoacetate, Butyl acetoacetate, Amyl acetoacetate, Hexyl acetoacetate, 2-Ethylhexyl acetoacetate, Dimethyl malonate, Dimethyl succinate, Dimethyl glutarate, Dimethyl adipate, Dimethyl phthalate, Dimethyl maleate, Diethyl malonate, Diethyl succinate, Diethyl glutarate, Diethyl adipate, Diethyl phthalate, Diethyl maleate, Dipropyl malonate, Diethyl succinate Propyl phthalate, dipropyl glutarate, dipropyl adipate, dipropyl phthalate, dipropyl maleate, dibutyl malonate, dibutyl succinate, dibutyl glutarate, dibutyl adipate, dibutyl phthalate, dibutyl maleate, dipentyl malonate, dipentyl succinate, dipentyl glutarate, dipentyl adipate, dipentyl phthalate, dipentyl maleate, dihexyl malonate, dihexyl succinate, dihexyl glutarate, dihexyl adipate, dihexyl phthalate, dihexyl maleate, di-2-ethylhexyl malonate, 2-ethylhexyl succinate, 2-ethylhexyl glutarate, 2-ethylhexyl adipate, 2-ethylhexyl phthalate, 2-ethylhexyl maleate (hereinafter also referred to as "specific organic solvents"), etc. These organic solvents can be used alone or in mixtures.

[0089] As a free radical polymerization method, it is not particularly limited and can use emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation polymerization, bulk polymerization, solution polymerization, etc.

[0090] As for the organic solvents used in free radical polymerization reactions, there are no particular limitations on the organic solvents used to dissolve the resulting polymer. Specific examples include the aforementioned organic solvents. These organic solvents can be used alone or in combination of two or more.

[0091] Furthermore, even solvents that do not dissolve the generated polymer can be mixed with the aforementioned organic solvents and used within the range where the generated polymer does not precipitate.

[0092] It should be noted that in free radical polymerization, oxygen in the organic solvent becomes the cause of the polymerization reaction, so it is preferable to use organic solvents that are as degassed as possible.

[0093] It should be noted that when the polymer obtained by the above polymerization is dissolved in the reaction solution, the reaction solution can be directly used for the preparation of the liquid crystal alignment agent, or the polymer contained in the reaction solution can be separated and used for the preparation of the liquid crystal alignment agent.

[0094] The polymerization temperature for free radical polymerization can be selected from any temperature between 30 and 150°C, preferably in the range of 50 to 100°C. The reaction can be carried out at any concentration. If the concentration is too low, it is difficult to obtain a high molecular weight polymer; if the concentration is too high, the viscosity of the reaction solution becomes too high, making uniform stirring difficult. Therefore, the monomer concentration is preferably 5 to 70% by mass, more preferably 10 to 50% by mass. In addition, an organic solvent can be added during the polymerization process to apply a gradient to the polymerization concentration.

[0095] For the polymer generated from the reaction solution obtained through the above reaction, the reaction solution can be precipitated and recovered by adding it to a poor solvent, but this reprecipitation process is not necessary. Examples of poor solvents used for precipitation include: methanol, acetone, hexane, heptane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, diethyl ether, methyl ethyl ether, and water. The polymer precipitated by adding it to a poor solvent can be recovered by filtration and then dried at room temperature or under normal or reduced pressure. Furthermore, if the operation of redissolving the recovered polymer in an organic solvent and reprecipitating it is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of poor solvents used in this process include, for example, alcohols, ketones, and hydrocarbons. Using three or more of these poor solvents further improves the purification efficiency and is therefore preferred.

[0096] (Liquid crystal alignment agent) Examples of organic solvents used as liquid crystal alignment agents in this invention include: N,N-dimethylformamide, N,N-dimethylacetamide, N-methylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolinone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethylphosphoramide, etc. γ-Butyl lactone, isopropanol, methoxymethylpentanol, dipentene, ethylpentyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isopentyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, butyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol tert-butyl ether, propylene glycol monomethyl ether acetate, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate Diethyl ester monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate 3-Methoxypropionate, diethylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, 2-(2-ethoxypropoxy)propanol, 2-ethyl-1,3-hexanediol, propylene glycol (1,2-propanediol), 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol Diols, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,3-hexanediol, 2,4-hexanediol, 2,5-hexanediol, 3,5-hexanediol, 1,2-heptanediol, 1,3-heptanediol, 1,4-heptanediol, 1,5-heptanediol, 1,6-heptanediol, 1,7-heptanediol, 1,2-octanediol, 1,4-octanediol, 1,8-octanediol, 1,2-nonanediol, 1,3-nonanediol, 1,5-nonanediol, 1,6-nonanediol, 1,9-nonanediol, 1,2-decanediol, 1,5-decanediol, 1,8-decanediol, 1,10-decanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-Cyclohexanediol, dipropylene glycol, dibutyl glycol, glycerin, 2-ethyl-1-hexanol, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, pentyl pyruvate, hexyl pyruvate, 2-ethylhexyl pyruvate, methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, butyl acetoacetate, pentyl acetoacetate, hexyl acetoacetate, 2-ethylhexyl acetoacetate, methyl acetopropionate, ethyl acetopropionate, propyl acetopropionate, butyl acetopropionate, pentyl acetopropionate, hexyl acetopropionate, 2-ethylhexyl acetopropionate, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, dimethyl phthalate, dimethyl maleate, diethyl malonate, diethyl succinate, diethyl glutarate, diethyl adipate, diethyl phthalate, diethyl maleate Dipropyl malonate, dipropyl succinate, dipropyl glutarate, dipropyl adipate, dipropyl phthalate, dipropyl maleate, dibutyl malonate, dibutyl succinate, dibutyl glutarate, dibutyl adipate, dibutyl phthalate, dibutyl maleate, dipentyl malonate, dipentyl succinate, dipentyl glutarate, dipentyl adipate, dipentyl phthalate, dipentyl maleate, dipropyl succinate Dihexyl phthalate, dihexyl succinate, dihexyl glutarate, dihexyl adipate, dihexyl phthalate, dihexyl maleate, di-2-ethylhexyl malonate, 2-ethylhexyl succinate, 2-ethylhexyl glutarate, 2-ethylhexyl adipate, 2-ethylhexyl phthalate, 2-ethylhexyl maleate, etc., as well as other solvents that can be used as solvents, can be listed. These organic solvents can be used alone or in mixtures.

[0097] In addition, it is preferable to use a solvent that improves the uniformity and smoothness of the coating film in combination with a highly soluble organic solvent.

[0098] Solvents used to improve the uniformity and smoothness of coatings include, for example, isopropanol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, butyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol tert-butyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, and dipropylene glycol monopropyl ether. Dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl acetate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol 1-Ethoxy-2-propanol, 1-Butoxy-2-propanol, 1-Phenoxy-2-propanol, Propylene glycol diacetate, Propylene glycol-1-monomethyl ether-2-acetate, Propylene glycol-1-monoethyl ether-2-acetate, Dipropylene glycol, 2-(2-ethoxypropoxy)propanol, 2-Ethyl-1-hexanol, Methyl pyruvate, Ethyl pyruvate, Propyl pyruvate, Butyl pyruvate, Amyl pyruvate, Hexyl pyruvate, 2-Ethylhexyl pyruvate, Methyl acetoacetate, Ethyl acetoacetate, Propyl acetoacetate, Butyl acetoacetate, Amyl acetoacetate, Hexyl acetoacetate, 2-Ethylhexyl acetoacetate, Methyl acetoacetate, Ethyl acetoacetate, Propyl acetoacetate, Butyl acetoacetate, Amyl acetoacetate, Hexyl acetoacetate, Ethyl acetoacetate 2-Ethylhexyl acetate, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, dimethyl phthalate, dimethyl maleate, diethyl malonate, diethyl succinate, diethyl glutarate, diethyl adipate, diethyl phthalate, diethyl maleate, dipropyl malonate, dipropyl succinate, dipropyl glutarate, dipropyl adipate Dipropyl phthalate, dipropyl maleate, dibutyl malonate, dibutyl succinate, dibutyl glutarate, dibutyl adipate, dibutyl phthalate, dibutyl maleate, dipentyl malonate, dipentyl succinate, dipentyl glutarate, dipentyl adipate, dipentyl phthalate, dipentyl maleate, dihexyl malonate, dihexyl succinate, dihexyl glutarateDihexyl adipate, dihexyl phthalate, dihexyl maleate, di-2-ethylhexyl malonate, 2-ethylhexyl succinate, 2-ethylhexyl glutarate, 2-ethylhexyl adipate, 2-ethylhexyl phthalate, 2-ethylhexyl maleate, etc. These solvents can be mixed in multiples. When using these solvents, it is preferable that the total amount of solvents contained in the liquid crystal alignment agent is 5-80% by mass, more preferably 20-60% by mass.

[0099] The liquid crystal alignment agent of the present invention may also contain components other than those described above. Examples include: compounds that improve the voltage retention rate of liquid crystal cells, compounds that improve the film thickness uniformity and surface smoothness when coating the composition contained in the liquid crystal alignment agent, compounds that improve the adhesion between the composition contained in the liquid crystal alignment agent and the substrate, and compounds that further improve the film strength of the composition contained in the liquid crystal alignment agent.

[0100] Examples of compounds that improve the voltage retention rate of liquid crystal cells include compounds having an alkoxysilyl group and a urea structure with substitutions at the 1 and 3 positions (hereinafter also referred to as compound B).

[0101] The above compounds are not particularly limited in other structures as long as they have one or more alkoxysilyl groups and one or more 1,3-disubstituted urea structures. From the viewpoint of availability, the compound shown in formula (b) below is one of the preferred examples.

[0102] [Chemistry 12] In formula (b), Z is an aliphatic hydrocarbon group with 1 to 20 carbon atoms, or an r-valent organic group containing an aromatic hydrocarbon group, where r is an integer from 1 to 6, and R... 2 Represents a hydrogen atom or an alkyl group. When r is 2 or more, R... 2 Compared with other R 2 Together they form an alkylene group, or, in the case of r being 1–6, they can form a cyclic structure together with Z through bonding. J represents an alkylene group having 2–20 carbon atoms, and R... 3 and R 4 Each is independently an alkyl group with 1 to 4 carbon atoms, an alkenyl group with 2 to 4 carbon atoms, or an alkynyl group with 2 to 4 carbon atoms, and q represents an integer from 1 to 3.

[0103] As R 2 Alkyl groups, such as alkyl groups having 1 to 3 carbon atoms, are preferred, with methyl groups being the most common.

[0104] As R 3 and R 4Preferably, the alkyl group has 1 to 4 carbon atoms. Specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and sec-butyl. From the viewpoint of availability and reactivity of the raw materials, methyl or ethyl is preferred.

[0105] Examples of J include alkylene groups with 2 to 20 carbon atoms. From the perspective of raw material availability, trimethylene is preferred.

[0106] q is preferably 2 or 3, and particularly preferably 3.

[0107] r is preferably 1, 2 or 3, and particularly preferably 1 or 2.

[0108] Compound B can be any of the compounds shown in formulas (B-1) to (B-6) below.

[0109] [Chemistry 13] In formulas (B-1) to (B-6), R can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or sec-butyl, etc. From the viewpoint of raw material supply, methyl or ethyl is preferred, and from the viewpoint of improving the voltage retention rate of liquid crystal cells, methyl is particularly preferred.

[0110] In equation (B-1), X 1 The structure represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a divalent organic group containing an aromatic hydrocarbon group, preferably any one of the structures shown below.

[0111] [Chemistry 14] Among them, X 1 The structure shown in any of the following is particularly preferred.

[0112] [Chemistry 15] In equation (B-2), X 2 This refers to a divalent organic group having 1 to 20 carbon atoms in a cyclic structure with 2 or more nitrogen atoms, preferably any of the structures shown below. It should be noted that, for convenience, the following structural formulas include the nitrogen atoms within the ring.

[0113] [Chemistry 16] In equation (B-3), X 3This refers to a divalent organic group having one or more nitrogen atoms, wherein the nitrogen atom forms an alicyclic structure with 1 to 20 carbon atoms, preferably any of the structures shown below. It should be noted that, for convenience, the following structural formulas include the nitrogen atom within the ring.

[0114] [Chemistry 17] In equation (B-4), X 4 The structure represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a trivalent organic group containing an aromatic hydrocarbon group, preferably any one of the structures shown below.

[0115] [Chemistry 18] In equation (B-5), X 5 The structure represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent organic group containing an aromatic hydrocarbon group, preferably any one of the structures shown below.

[0116] [Chemistry 19] In equation (B-6), X 6 This refers to a monovalent organic group having one or more nitrogen atoms, wherein the nitrogen atom forms an alicyclic structure with 1 to 20 carbon atoms, preferably any of the structures shown below. It should be noted that, for convenience, the following structural formulas include the nitrogen atom within the ring.

[0117] [Chemistry 20] As a specific example of compound B, compounds represented by the following formulas AD-1 to AD-6 are preferably cited.

[0118] [Chemistry 21] If too much of the compound improves the voltage retention rate of the liquid crystal cell, it will affect the alignment of the liquid crystal; if too little, it will not be effective. Therefore, the amount added is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, relative to 100 parts by mass of the total amount of polymer (P) contained in the liquid crystal alignment agent.

[0119] Compounds used to improve film thickness uniformity and surface smoothness include fluorinated surfactants, organosilicon surfactants, and nonionic surfactants. More specifically, examples include: EFTOP EF301, EF303, EF352 (manufactured by Mitsubishi Materials Electronics & Chemicals Co., Ltd.), MEGAFAC F171, F173, R-30 (manufactured by DIC Corporation), Fluorad FC430, FC431 (manufactured by 3M Corporation), AsahiGuard AG710 (manufactured by AGC Corporation), SURFLONS-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by AGC Seimei Chemical Co., Ltd.), etc.

[0120] When using these surfactants, the proportion of their use relative to 100 parts by mass of the total amount of polymer contained in the composition contained in the strongly anchoring liquid crystal alignment agent is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass.

[0121] Specific examples of compounds that improve the adhesion between the composition contained in the liquid crystal alignment agent and the substrate include compounds containing functional silanes and compounds containing epoxy groups. Examples include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethyl... Oxycarbonyl-3-aminopropyltriethoxysilane, N-(3-triethoxysilyl)propyltriethylenetetramine, N-(3-trimethoxysilyl)propyltriethylenetetramine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonylacetate, 9-triethoxysilyl-3,6-diazanonylacetate, N-benzyl-3-aminopropyltriethoxysilane Methoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether Glyceryl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N′,N′-tetraglycidyl-m-phenylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane, 3-(N-allyl-N-glycidyl)aminopropyltrimethoxysilane, 3-(N,N-diglycidyl)aminopropyltrimethoxysilane, etc.

[0122] In addition, to further improve the film strength of the liquid crystal alignment film, phenolic compounds such as 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane and tetra(methoxymethyl)bisphenol can be added. When using these compounds, the amount is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, relative to 100 parts by mass of the total amount of polymer contained in the strong anchoring liquid crystal alignment agent.

[0123] Furthermore, in addition to the above, in the composition contained in the liquid crystal alignment agent, polyamic acid, polyamic acid ester, soluble polyimide, polyamide, polyurea, etc., may be added to change the dielectric constant, conductivity, and other electrical properties of the liquid crystal alignment film, as long as it does not impair the effect of the present invention.

[0124] In addition to the polymer (P) of the present invention, by mixing one or more polymers selected from polyimide, polyamic acid, polyamic acid ester, polyamide and polyurea (hereinafter also referred to as the second polymer), it is possible to control the viscosity of varnishes (e.g., liquid crystal alignment agents) that are difficult to achieve by the polymer (P) itself, and to improve the mechanical strength, sealing performance, and coatability of the liquid crystal alignment film.

[0125] When the second polymer uses polyamic acid, polyimide, or polyamic acid ester, all polyamic acid and polyimide are acceptable, but if a specific example is to be given, the following polymers containing diamine and tetracarboxylic dianhydride can be cited.

[0126] The following diamines can be cited as diamine components used in the synthesis of polyamic acid and polyimide. Specifically, they include: p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 2,5-diaminophenol, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-dihydroxy-4,4′-diaminobiphenyl, 3,3′-dicarboxy-4,4′-diaminobiphenyl, 3,3 3,3′-Difluoro-4,4′-diaminobiphenyl, 3,4′-diaminobiphenyl, 3,3′-diaminobiphenyl, 2,2′-diaminobiphenyl, 2,3′-diaminobiphenyl, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 2,2′-diaminodiphenylmethane, 2,3′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 2,2′-diaminodiphenyl ether, 2,3′-diaminodiphenyl ether, 4,4′-sulfonyl diphenylamine, 3,3′-sulfonyl Diphenylamine, bis(4-aminophenyl)silane, bis(3-aminophenyl)silane, dimethyl-bis(4-aminophenyl)silane, dimethyl-bis(3-aminophenyl)silane, 4,4′-thiodiphenylamine, 3,3′-thiodiphenylamine, 4,4′-diaminodiphenylamine, 3,3′-diaminodiphenylamine, 3,4′-diaminodiphenylamine, 2,2′-diaminodiphenylamine, 2,3′-diaminodiphenylamine, N-methyl(4,4′-diaminodiphenyl)amine, N-methyl(3,3′-diaminodiphenyl)amine, N-methyl(3,4′-diaminodiphenyl)amine, N-methyl(2,2′-diaminodiphenyl)amine, N-methyl(2,3′-diaminodiphenyl)amine )amine, 4,4′-diaminobenzophenone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 2,2′-diaminobenzophenone, 2,3′-diaminobenzophenone, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 1,8-diaminonaphthalene, 2,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 1,2-bis(4-aminophenyl)ethane, 1,2-bis(3-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1,3-bis(3-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,4-bis(3-aminophenyl)butane, bis(3,5-Diethyl-4-aminophenyl)methane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4′-[1,4-phenylenebis(methylene)]diphenylamine, 4,4′-[1,3-phenylenebis(methylene)]diphenylamine, 3,4′-[1,4-phenylenebis(methylene)]diphenylamine, 3,4′-[1,3-phenylenebis(methylene)]diphenylamine, 3,3′-[1,4-phenylenebis(methylene)]diphenylamine, 3,3′-[1,3 ... [1,4-phenylenebis[(4-aminophenyl) ketone], 1,4-phenylenebis[(3-aminophenyl) ketone], 1,3-phenylenebis[(4-aminophenyl) ketone], 1,3-phenylenebis[(3-aminophenyl) ketone], 1,4-phenylenebis(4-aminobenzoate), 1,4-phenylenebis(3-aminobenzoate), 1,3-phenylenebis(4-aminobenzoate), 1,3-phenylenebis(3-aminobenzoate), bis(4-aminophenyl) terephthalate, bis(3-aminophenyl) terephthalate, bis(4-aminophenyl) isophthalate, bis(3-aminophenyl) isophthalate, N,N′-(1,4-phenylene)bis (4-Aminobenzamide), N,N′-(1,3-phenylene)bis(4-aminobenzamide), N,N′-(1,4-phenylene)bis(3-aminobenzamide), N,N′-(1,3-phenylene)bis(3-aminobenzamide), N,N′-bis(4-aminophenyl)terephthalamide, N,N′-bis(3-aminophenyl)terephthalamide, N,N′-bis(4-aminophenyl)isophthalamide, N,N′-bis(3-aminophenyl)isophthalamide, 9,10-bis(4-aminophenyl)anthracene, 4,4′-bis(4-aminophenoxy)diphenyl sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane [2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(3-amino-4-methylphenyl)propane, trans-1,4-bis(4-aminophenyl)cyclohexane, 3,5-diaminobenzoic acid, 2,5-diaminobenzoic acid, bis(4-aminophenoxy)methane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,3-bis(3-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,4-Di(3-aminophenoxy)butane, 1,5-Di(4-aminophenoxy)pentane, 1,5-Di(3-aminophenoxy)pentane, 1,6-Di(4-aminophenoxy)hexane, 1,6-Di(3-aminophenoxy)hexane, 1,7-Di(4-aminophenoxy)heptane, 1,7-Di(3-aminophenoxy)heptane, 1,8-Di(4-aminophenoxy)octane, 1,8-Di(3-aminophenoxy)octane, 1, Aromatic diamines such as 9-bis(4-aminophenoxy)nonane, 1,9-bis(3-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, 1,10-bis(3-aminophenoxy)decane, 1,11-bis(4-aminophenoxy)undecane, 1,11-bis(3-aminophenoxy)undecane, 1,12-bis(4-aminophenoxy)dodecane, and 1,12-bis(3-aminophenoxy)dodecane; bis(4- Alicyclic diamines such as aminocyclohexyl)methane and bis(4-amino-3-methylcyclohexyl)methane; alicyclic diamines such as 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane; 1,3-bis[2-( Diamines with a urea structure include p-aminophenyl)ethyl]urea and 1,3-bis[2-(p-aminophenyl)ethyl]-1-tert-butoxycarbonylurea; diamines with a nitrogen-containing unsaturated heterocyclic structure include N-p-aminophenyl-4-p-aminophenyl(tert-butoxycarbonyl)aminomethylpiperidine; and diamines with an N-Boc group (Boc represents tert-butoxycarbonyl) include N-tert-butoxycarbonyl-N-(2-(4-aminophenyl)ethyl)-N-(4-aminobenzyl)amine.

[0127] The above-mentioned diamines can be used alone or in combination of two or more.

[0128] There are no particular limitations on the tetracarboxylic acid dianhydrides that react with the aforementioned diamine components. Specifically, examples include: pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7-anthracitetetracarboxylic acid, 1,2,5,6-anthracitetetracarboxylic acid, 3,3′,4,4′-biphenyltetracarboxylic acid, 2,3,3′,4′-biphenyltetracarboxylic acid, bis(3,4-dicarboxyphenyl) ether, 3,3′,4,4′-benzophenonetetracarboxylic acid, bis(3,4-dicarboxyphenyl) sulfone, bis(3,4-dicarboxyphenyl)methane, 2,2-bis(3,4-dicarboxyphenyl)propane, 1,1,1,3,3,3-hexafluoro-2,2-bis(3,4-dicarboxyphenyl)propane. Alkane, bis(3,4-dicarboxyphenyl)dimethylsilane, bis(3,4-dicarboxyphenyl)diphenylsilane, 2,3,4,5-pyridinetetracarboxylic acid, 2,6-bis(3,4-dicarboxyphenyl)pyridine, 3,3′,4,4′-diphenylsulfonetetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic acid, 1,3-diphenyl-1,2,3,4-cyclobutanetetracarboxylic acid, oxydiphthalic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid, 1,2-dimethyl-1,2,3,4-cyclohexanetetracarboxylic acid Butanetetracarboxylic acid, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cycloheptanetetracarboxylic acid, 2,3,4,5-tetrahydrofurantetracarboxylic acid, 3,4-dicarboxy-1-cyclohexylsuccinic acid, 2,3,5-tricarboxycyclopentylacetic acid, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthoussuccinic acid, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic acid, bicyclo[4.3.0]nonane-2,4,7,9-tetracarboxylic acid, bicyclo[4.4.0]decane-2,4,7,9-tetracarboxylic acid, bicyclo[4.4.0]decane-2,4,8,10-tetracarboxylic acid, tricyclo[6.3.0] The dianhydrides of tetracarboxylic acids, including undecane-3,5,9,11-tetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid, 5-(2,5-dioxotetrahydrofuranyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic acid, tetracyclo[6.2.1.1.0<2,7>]dodecane-4,5,9,10-tetracarboxylic acid, 3,5,6-tricarboxylated norbornane-2,3,5,6-tetracarboxylic acid, and 1,2,4,5-cyclohexanetetracarboxylic acid.

[0129] Of course, tetracarboxylic acid dianhydrides can be used alone or in combination with two or more.

[0130] In the synthesis of the second polymer being a polyamic acid ester, the structure of the tetracarboxylic acid dialkyl ester that reacts with the above-mentioned diamine component is not particularly limited, and specific examples are given below.

[0131] Specific examples of aliphatic tetracarboxylic acid diesters include: 1,2,3,4-cyclobutanetetracarboxylic acid dialkyl ester, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dialkyl ester, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dialkyl ester, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid dialkyl ester, 1,2,3,4-cyclopentanetetracarboxylic acid dialkyl ester, 2,3,4,5-tetrahydrofurantetracarboxylic acid dialkyl ester, 1,2,4,5-cyclohexanetetracarboxylic acid dialkyl ester, 3,4-dicarboxy-1-cyclohexylsuccinate dialkyl ester, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthylsuccinate dialkyl ester, 1,2,3,4-butanetetracarboxylic acid dialkyl ester, and bicyclic [3.3.0] Octane-2,4,6,8-tetracarboxylic acid dialkyl ester, 3,3′,4,4′-dicyclohexyltetracarboxylic acid dialkyl ester, 2,3,5-tricarboxylated cyclopentylacetic acid dialkyl ester, cis-3,7-dibutylcyclooctyl-1,5-diene-1,2,5,6-tetracarboxylic acid dialkyl ester, tricyclo[4.2.1.0<2,5>]nonane-3,4,7,8-tetracarboxylic acid-3,4:7,8-dialkyl ester, hexacyclo[6.6.0.1<2,7>.0<3,6>.1<9,14>.0<10,13>]hexadecane-4,5,11,12-tetracarboxylic acid-4,5:11,12-dialkyl ester, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid dialkyl ester, etc.

[0132] Examples of aromatic tetracarboxylic acid dialkyl esters include: pyromellitic ester, 3,3′,4,4′-biphenyltetracarboxylic acid dialkyl ester, 2,2′,3,3′-biphenyltetracarboxylic acid dialkyl ester, 2,3,3′,4′-biphenyltetracarboxylic acid dialkyl ester, 3,3′,4,4′-benzophenone tetracarboxylic acid dialkyl ester, 2,3,3′,4′-benzophenone tetracarboxylic acid dialkyl ester, bis(3,4-dicarboxyphenyl) ether dialkyl ester, bis(3,4-dicarboxyphenyl) sulfone dialkyl ester, 1,2,5,6-naphthalenetetracarboxylic acid dialkyl ester, 2,3,6,7-naphthalenetetracarboxylic acid dialkyl ester, etc.

[0133] In the case where the second polymer is a polyurea, regardless of the polyurea used or its synthesis method, polymers containing diamines and diisocyanates can be cited.

[0134] Examples of diamines include those used in the synthesis of polyamic acid and polyimide.

[0135] In the synthesis of polyurea, there are no particular limitations on the diisocyanate that reacts with the aforementioned diamine component, and it can be used depending on availability, etc. The specific structure of the diisocyanate is shown below.

[0136] [Chemistry 22] (In the formula, R3 and R4 represent aliphatic hydrocarbon groups with 1 to 10 carbon atoms.) Examples of aliphatic hydrocarbon groups having 1 to 10 carbon atoms include straight-chain or branched alkylene groups having 1 to 10 carbon atoms, and straight-chain or branched alkenyl groups having 2 to 10 carbon atoms.

[0137] Examples of linear or branched alkylene groups having 1 to 10 carbon atoms include: methylene, methylmethylene, dimethylmethylene, ethylene, propylene, trimethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decylene, etc.

[0138] Examples of alkenyl groups that are straight-chain or branched and have 2 to 10 carbon atoms include: vinylidene, 1-methylvinylidene, propenylidene, 1-butenylidene, 2-butenylidene, hexenylidene, heptenylidene, octeneylidene, nonenylidene, etc.

[0139] Aliphatic diisocyanates represented by formulas (K-1) to (K-5) have poor reactivity but offer the advantage of improved solvent solubility. Aromatic diisocyanates represented by formulas (K-6) to (K-13) are highly reactive and improve heat resistance, but suffer from reduced solvent solubility. In terms of versatility and properties, formulas (K-1), (K-7), (K-8), (K-9), and (K-10) are preferred; from the viewpoint of electrical properties, formula (K-12) is preferred; and from the viewpoint of liquid crystal alignment, formula (K-13) is preferred. Two or more diisocyanates can also be used in combination, and various applications are preferably performed according to the desired properties.

[0140] Alternatively, a portion of the diisocyanate can be replaced with the tetracarboxylic dianhydride described above, and it can be used in the form of a copolymer of polyamic acid and polyurea, or it can be used in the form of a copolymer of polyimide and polyurea through chemical imidization.

[0141] When the second polymer is a polyamide, all polyamides are acceptable, but if a specific example is given, polymers containing diamines and dicarboxylic acids can be cited.

[0142] Examples of diamines include those used in the synthesis of polyamic acid and polyimide.

[0143] In the synthesis of polyamides, the structure of the dicarboxylic acid that reacts with the above-mentioned diamine components is not particularly limited; specific examples are given below.

[0144] Examples of aliphatic dicarboxylic acids include: malonic acid, oxalic acid, dimethylmalonic acid, succinic acid, fumaric acid, glutaric acid, adipic acid, adipate, 2-methyl adipic acid, trimethyl adipic acid, pimelic acid, 2,2-dimethylglutaric acid, 3,3-diethylsuccinic acid, azelaic acid, sebacic acid, and octanoic acid.

[0145] Examples of alicyclic dicarboxylic acids include: 1,1-cyclopropanedicarboxylic acid, 1,2-cyclopropanedicarboxylic acid, 1,1-cyclobutanedicarboxylic acid, 1,2-cyclobutanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid, 3,4-diphenyl-1,2-cyclobutanedicarboxylic acid, 2,4-diphenyl-1,3-cyclobutanedicarboxylic acid, 1-cyclobutene-1,2-dicarboxylic acid, 1-cyclobutene-3,4-dicarboxylic acid, 1,1-cyclopentanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,1-cyclohexanedicarboxylic acid, 1,2-cyclopropanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,1-cyclohexanedicarboxylic acid, 1,2-cyclopropanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,1-cyclohexanedicarboxylic acid, 1,2-cyclopropanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclopropanedicarboxylic acid, 1,3-cyclopropanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,3 ...propanedicarboxylic acid, 1,3-cycloprop Hexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-(2-norbornene)dicarboxylic acid, norbornene-2,3-dicarboxylic acid, bicyclo[2.2.2]octane-1,4-dicarboxylic acid, bicyclo[2.2.2]octane-2,3-dicarboxylic acid, 2,5-dioxo-1,4-bicyclo[2.2.2]octanedicarboxylic acid, 1,3-adamantanedicarboxylic acid, 4,8-dioxo-1,3-adamantanedicarboxylic acid, 2,6-spiro[3.3]heptanedicarboxylic acid, 1,3-adamantanediacetic acid, camphoric acid, etc.

[0146] Examples of aromatic dicarboxylic acids include: phthalic acid, isophthalic acid, terephthalic acid, 5-methylisophthalic acid, 5-tert-butylisophthalic acid, 5-aminoisophthalic acid, 5-hydroxyisophthalic acid, 2,5-dimethylterephthalic acid, tetramethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-anthraquinone dicarboxylic acid, 1,4-anthraquinone dicarboxylic acid, 2,5-biphenyl dicarboxylic acid, 4, 4′-Biphenyl dicarboxylic acid, 1,5-Biphenylene dicarboxylic acid, 4,4′′-Triphenyl dicarboxylic acid, 4,4′-Diphenylmethane dicarboxylic acid, 4,4′-Diphenylethane dicarboxylic acid, 4,4′-Diphenylpropane dicarboxylic acid, 4,4′-Diphenylhexafluoropropane dicarboxylic acid, 4,4′-Diphenyl ether dicarboxylic acid, 4,4′-Bibenzyl dicarboxylic acid, 4,4′-Azuldicarboxylic acid, 4,4′-Diphenylacetylene dicarboxylic acid (4,4′-tolandicarboxylic acid) dicarboxylic acids, including 4,4′-carbonyldibenzoic acid, 4,4′-sulfonyldibenzoic acid, 4,4′-dithiodibenzoic acid, p-phenylene diacetic acid, 3,3′-p-phenylene dipropionic acid, 4-carboxycinnamic acid, p-phenylene diacrylic acid, 3,3′-[4,4′-(methylene dip-phenylene)]dipropionic acid, 4,4′-[4,4′-(oxodip-phenylene)]dipropionic acid, 4,4′-[4,4′-(oxodip-phenylene)]dibutyric acid, (isopropylidene dip-phenylenedioxy)dibutyric acid, and bis(p-carboxyphenyl)dimethylsilane.

[0147] Examples of heterocyclic dicarboxylic acids include: 1,5-(9-oxofluorene)dicarboxylic acid, 3,4-furandicarboxylic acid, 4,5-thiazoledicarboxylic acid, 2-phenyl-4,5-thiazoledicarboxylic acid, 1,2,5-thiadiazole-3,4-dicarboxylic acid, 1,2,5-oxadiazole-3,4-dicarboxylic acid, 2,3-pyridinedicarboxylic acid, 2,4-pyridinedicarboxylic acid, 2,5-pyridinedicarboxylic acid, 2,6-pyridinedicarboxylic acid, 3,4-pyridinedicarboxylic acid, and 3,5-pyridinedicarboxylic acid.

[0148] The various dicarboxylic acids described above can be substances with the structure of acid dihalides or anhydrides. In terms of maintaining the orientation of liquid crystal molecules, these dicarboxylic acids are particularly preferred to be dicarboxylic acids capable of imparting a linear structure to polyamides. Among these, terephthalic acid, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, 4,4′-diphenylmethanedicarboxylic acid, 4,4′-diphenylethanedicarboxylic acid, 4,4′-diphenylpropanedicarboxylic acid, 4,4′-diphenylhexafluoropropanedicarboxylic acid, 2,2-bis(phenyl)propanedicarboxylic acid, 4,4′′-triphenyl dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,5-pyridinedicarboxylic acid, or their acid dihalides are preferred. These compounds sometimes exist as isomers and can be mixtures containing them. Furthermore, two or more compounds can be used in combination. It should be noted that the dicarboxylic acids used in this invention are not limited to the compounds exemplified above.

[0149] Polyamic acid, polyamic acid ester, polyurea, and polyamide can be obtained by reacting a diamine (also referred to as "diamine component") as a starting material with a component selected from tetracarboxylic dianhydride (also referred to as "tetracarboxylic dianhydride component"), tetracarboxylic acid diester, diisocyanate, and dicarboxylic acid as a starting material using known synthetic methods. Generally, the method involves reacting the diamine component with one or more components selected from tetracarboxylic dianhydride component, tetracarboxylic acid diester, diisocyanate, and dicarboxylic acid in an organic solvent.

[0150] Polyamic acid can be synthesized by reacting a tetracarboxylic acid derivative containing tetracarboxylic acid dianhydride with the above-mentioned diamine component in the presence of an organic solvent at -20 to 150°C, preferably 0 to 50°C (condensation reaction) for 30 minutes to 24 hours, preferably 1 to 12 hours.

[0151] Polyamates can be manufactured by known methods such as (1) esterification of the above-mentioned polyamates, (2) reaction of the above-mentioned diamine component with a tetracarboxylic acid derivative component containing a tetracarboxylic acid diester dichloride, and (3) polycondensation of the tetracarboxylic acid derivative component containing a tetracarboxylic acid diester with a diamine.

[0152] Polyimide can be synthesized by known methods such as (1) directly heating the solution of the above-mentioned polyamic acid or polyamic acid ester, or (2) catalytic imidization of the above-mentioned polyamic acid or polyamic acid ester solution by adding a catalyst (e.g., basic catalyst such as pyridine, acid anhydride such as acetic anhydride).

[0153] Polyurea can be synthesized by reacting the above-mentioned diisocyanate with the above-mentioned diamine component in the presence of an organic solvent at -20 to 150°C, preferably at 0 to 50°C (condensation reaction) for 30 minutes to 24 hours, preferably 1 to 12 hours.

[0154] Polyamides can be manufactured by known methods such as (1) reacting a dicarboxylic acid dichloro derivative with the aforementioned diamine, and (2) polycondensing a dicarboxylic acid derivative with a diamine.

[0155] The organic solvent used in the synthesis of the second polymer can be any organic solvent that does not chemically react with the compounds constituting the second polymer and does not perform free radical scavenging; it can be selected from organic solvents that can be used in the synthesis of the aforementioned polymer (P). Furthermore, one organic solvent can be used alone, or two or more can be used in combination.

[0156] The weight-average molecular weight (Mw) of the polyamic acid, polyamic acid ester, soluble polyimide, polyurea, and polyamide, as determined by gel permeation chromatography (GPC), is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC, is preferably 15 or less, more preferably 10 or less. By falling within the above molecular weight range, excellent liquid crystal orientation can be exhibited, and excellent coatability can be obtained regardless of the coating method.

[0157] (Liquid crystal alignment film and liquid crystal display element) The liquid crystal display element of the present invention includes a liquid crystal alignment film formed using the above-described liquid crystal alignment agent. In the case of forming a polymer of a strongly anchoring liquid crystal alignment agent having an alignment limiting force in the horizontal direction, an in-plane switching type (IPS type, FFS type) is preferred.

[0158] The liquid crystal display element of the present invention can be manufactured, for example, by a method comprising the following steps (1) to (4).

[0159] <Process (1): The process of coating the liquid crystal alignment agent onto the substrate> Step (1) is the process of applying a liquid crystal alignment agent onto a substrate. The specific details of step (1) are shown below.

[0160] On one side of a substrate with a patterned transparent conductive film, a liquid crystal alignment agent is applied using a suitable coating method such as roll coating, spin coating, printing, inkjet coating, or spray coating. Here, the substrate material is not particularly limited as long as it has high transparency; it can be used with glass, silicon nitride, or plastics such as acrylic or polycarbonate. Furthermore, in reflective liquid crystal display elements, if only a single-sided substrate is used, even opaque materials such as silicon wafers can be used, and the electrodes can be made of light-reflecting materials such as aluminum. Additionally, in the manufacture of IPS or FFS type liquid crystal display elements, a substrate with electrodes including a patterned comb-shaped transparent conductive film or metal film and an opposing substrate without electrodes are used.

[0161] The comb electrode substrate used in IPS type liquid crystal display elements, namely the IPS substrate, has, for example, a substrate, a plurality of linear electrodes formed on the substrate and arranged in a comb shape, and a liquid crystal alignment film formed in such a way as to cover the linear electrodes on the substrate.

[0162] It should be noted that the comb electrode substrate used in the FFS type liquid crystal display element is the FFS substrate, which, for example, has: a substrate, a surface electrode formed on the substrate, an insulating film formed on the surface electrode, a plurality of linear electrodes formed on the insulating film and arranged in a comb shape, and a liquid crystal alignment film formed in such a way as to cover the linear electrodes on the insulating film.

[0163] More preferred examples of methods for coating a liquid crystal alignment agent onto a substrate and forming a film include: printing methods such as screen printing, offset printing, or flexographic printing; spin coating; inkjet printing; and spray coating. Among these, flexographic printing, spin coating, or inkjet printing are preferred methods for coating and forming films.

[0164] <Process (2): Drying the coated liquid crystal alignment agent> Step (2) is a process of drying the liquid crystal alignment agent coated on the substrate to remove a minimum amount of solvent. A specific example of step (2) is shown below.

[0165] After the liquid crystal alignment agent is coated onto the substrate in step (1), the solvent can be evaporated or the polyamic acid can be thermally imidized using heating methods such as a heating plate, a hot air circulating oven, or an IR (infrared) oven. The drying and firing processes after coating the liquid crystal alignment agent can be performed at any temperature and for any time, and can be repeated multiple times. For example, the firing temperature of the liquid crystal alignment agent can be 40 to 180°C. There is no particular limitation on the firing time, and firing times of 5 to 40 minutes or 5 to 30 minutes can be given.

[0166] If the film thickness of the fired film is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, 5 to 300 nm is preferred, and 10 to 200 nm is more preferred.

[0167] <Step (3): The step of photo-aligning the film obtained in step (2)> Step (3) is a process of photo-aligning the film obtained in step (2). That is, in horizontally aligned liquid crystal display elements such as IPS or FFS, the coating is treated to impart uniaxial alignment capability in the horizontal direction. As a photo-aligning treatment method, an example is to irradiate the surface of the above-mentioned film with 254nm radiation deflected in a certain direction, and then perform heat treatment at the liquid crystal performance temperature of the photo-alignment compound shown in (1) above to impart liquid crystal alignment (also known as liquid crystal alignment capability). The characteristic is that, as the radiation, ultraviolet light with a wavelength of 100 to 300nm can be used, and the proportion of 254nm light is more than 90% relative to the total amount of light with wavelengths of 254nm, 313nm and 365nm.

[0168] The preferred radiation dose is 1–10,000 mJ / cm². 2 More preferably, it is 100–5000 mJ / cm³. 2 Furthermore, to improve liquid crystal alignment when irradiated with radiation, the substrate having the above-described film can be irradiated while being heated at 50–250°C. The liquid crystal alignment film thus produced enables the liquid crystal molecules to be stably aligned in a specific direction.

[0169] Furthermore, water or solvents can be used to contact the coating film irradiated with polarized radiation using the above method. Alternatively, the film that has undergone the above-described orientation treatment can be subjected to heat treatment without contact treatment. Furthermore, the film that has undergone the above-described contact treatment can be further subjected to heat treatment.

[0170] The solvent used in the above-mentioned contact treatment is not particularly limited as long as it dissolves the decomposition products generated from the film-like material by radiation irradiation. Specific examples include: water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, etc. One solvent may be used alone, or two or more solvents may be used in combination.

[0171] The temperature for heat treatment of the radiation-irradiated coating is more preferably 50–300°C, and even more preferably 120–250°C. The heat treatment time is preferably set to 1–30 minutes.

[0172] <Process (4): Process of manufacturing liquid crystal cells> Prepare two substrates with liquid crystal alignment films formed as described above, and place liquid crystal between the two opposing substrates. Specifically, the following two methods can be used.

[0173] The first method involves first arranging two substrates facing each other with a gap (cell gap) between them, with each liquid crystal alignment film facing the other. Next, a sealant is applied to the periphery of the two substrates, they are then bonded together, and a liquid crystal composition is injected into the substrate surface and into the cell gap defined by the sealant until it contacts the film surface. Finally, the injection hole is sealed.

[0174] Another method is known as the ODF (One Drop Fill) method. On one of two substrates with a liquid crystal alignment film, a sealant, for example, that is UV-curable, is applied to predetermined locations on one of the substrates. A liquid crystal composition is then dropped onto predetermined locations on the surface of the alignment film. The other substrate is then bonded together with the alignment films facing each other, allowing the liquid crystal composition to spread across the entire surface of the substrate and contact the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. In either method, it is desirable to further heat the liquid crystal composition to a temperature at which it becomes an isotropic phase, and then slowly cool it to room temperature, thereby removing the flow alignment during liquid crystal filling.

[0175] As a sealant, for example, epoxy resin containing a curing agent and alumina spheres as spacers can be used. There are no particular limitations on the liquid crystal composition described above; various liquid crystal compositions containing at least one liquid crystal compound (liquid crystal molecule) and having positive or negative dielectric anisotropy can be used. It should be noted that, hereinafter, liquid crystal compositions with positive dielectric anisotropy are also referred to as positive liquid crystals, and liquid crystal compositions with negative dielectric anisotropy are also referred to as negative liquid crystals.

[0176] Examples of positive liquid crystal displays include ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081 manufactured by Merck.

[0177] Examples of negative liquid crystals include MLC-6608, MLC-6609, MLC-6610, and MLC-7026-100 manufactured by Merck.

[0178] The liquid crystal alignment film of the present invention is also preferably used in liquid crystal display elements (PSA type liquid crystal display elements), which are manufactured by the following steps: having a liquid crystal layer between a pair of substrates having electrodes, disposing a liquid crystal composition containing a polymerizable compound that is polymerized by at least one of active energy rays and heat between the pair of substrates, applying a voltage between the electrodes, and polymerizing the polymerizable compound by at least one of irradiation by active energy rays and heat.

[0179] Furthermore, the liquid crystal alignment film of the present invention is also preferably used in liquid crystal display elements (SC-PVA type liquid crystal display elements), which are manufactured by the following steps: having a liquid crystal layer between a pair of substrates having electrodes, disposing a liquid crystal alignment film containing polymeric groups that are polymerized by at least one of active energy rays and heat between the pair of substrates, and applying a voltage between the electrodes.

[0180] Furthermore, a polarizing plate can be attached to the outer surface of the liquid crystal cell as needed, thereby obtaining a liquid crystal display element. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include polarizing plates made by using a cellulose acetate protective film to hold a polarizing film called an "H film" that absorbs iodine while being stretched and oriented by polyvinyl alcohol, and polarizing plates that include the H film itself.

[0181] Figure 1 This is a schematic cross-sectional view showing an example of an IPS mode transverse electric field liquid crystal display element having a liquid crystal alignment film obtained by the liquid crystal alignment agent of the present invention.

[0182] exist Figure 1 In the illustrated lateral electric field liquid crystal display element 1, liquid crystal 3 is sandwiched between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2c and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 includes: a substrate 2a, a plurality of linear electrodes 2b formed on the substrate 2a and arranged in a comb-like shape, and a liquid crystal alignment film 2c formed on the substrate 2a to cover the linear electrodes 2b. The opposing substrate 4 includes: a substrate 4b, and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2c is the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4c is also the liquid crystal alignment film of the present invention.

[0183] exist Figure 1 In the transverse electric field liquid crystal display element 1, if a voltage is applied to the linear electrode 2b, an electric field is generated between the linear electrodes 2b as shown by the electric field line L.

[0184] Figure 2 This is a schematic cross-sectional view showing an example of a transverse electric field liquid crystal display element having an FFS mode liquid crystal alignment film obtained by the liquid crystal alignment agent of the present invention.

[0185] exist Figure 2 In the illustrated lateral electric field liquid crystal display element 1, liquid crystal 3 is sandwiched between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2h and a counter substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 includes: a substrate 2d, a surface electrode 2e formed on the substrate 2d, an insulating film 2f formed on the surface electrode 2e, a plurality of linear electrodes 2g formed on the insulating film 2f and arranged in a comb-like pattern, and a liquid crystal alignment film 2h formed on the insulating film 2f to cover the linear electrodes 2g. The counter substrate 4 includes: a substrate 4b, and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2h is the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4a is also the liquid crystal alignment film of the present invention.

[0186] exist Figure 2 In the transverse electric field liquid crystal display element 1, if a voltage is applied to the surface electrode 2e and the linear electrode 2g, an electric field is generated between the surface electrode 2e and the linear electrode 2g as shown by the electric field line L.

[0187] Example The following examples illustrate the invention in more detail, but the invention is not limited to these examples. The abbreviations used in the examples are as follows.

[0188] <Free radical polymerization monomers> [Chemistry 23] <Diamine> [Chemistry 24] <Tetracarboxylic dianhydride> [Chemistry 25] <Additives> [Chemistry 26] <Molecular weight control agent> [Chemistry 27] <Polymerization Initiator> [Chemistry 28] <Organic Solvents> THF: Tetrahydrofuran NMP: N-methyl-2-pyrrolidone BCS: Butyl Solvent <Synthesis of Homopolymers> (Synthesis Example 1-1) M-1 (5.00 g: 20.0 mmol) and AIBN (0.164 g: 0.600 mmol) were dissolved in THF (20.7 g) and degassed using a diaphragm pump. The mixture was heated and stirred at 60 °C for 18 hours under a nitrogen atmosphere. The reaction solution was then added dropwise to methanol (100 ml), and the resulting precipitate was separated by filtration. The precipitate was washed three times with methanol (100 ml) and dried under reduced pressure to obtain polymer powder p(M-1). The polymer has a Mn of 12300 and a Mw of 24900.

[0189] The raw materials used were replaced with those shown in Table 1 below, and the process was carried out in the same manner as in Synthesis Example 1-1, thereby obtaining the homopolymer shown in Table 1 below.

[0190] [Table 1] <Synthesis of Copolymers> (Synthesis example 2-1) M-3 (3.00 g: 9.79 mmol), M-4 (0.784 g: 2.45 mmol), and AIBN (0.101 g: 0.612 mmol) were dissolved in THF (15.1 g) and degassed using a diaphragm pump. The mixture was heated and stirred at 60 °C for 18 hours under a nitrogen atmosphere. The reaction solution was then added dropwise to methanol (100 ml), and the resulting precipitate was separated by filtration. The precipitate was washed three times with methanol (100 ml) and dried under reduced pressure to obtain polymer powder p(M-3 / M-4). The polymer has a Mn of 13100 and a Mw of 30900.

[0191] The same procedure as in Synthesis Example 2-1 was followed, except that the types of raw materials used were replaced with those shown in Table 2 below, thereby obtaining the copolymers shown in Table 2 below.

[0192] [Table 2] <Synthesis of Homopolymers Using Molecular Weight Control Agents> (Synthesis example 3-1) M-3 (5.00 g: 16.3 mmol), R-3 (439 mg: 1.09 mmol), and AIBN (89.3 mg: 0.544 mmol) were dissolved in THF (8.29 g) and degassed using a diaphragm pump. The mixture was heated and stirred at 60 °C for 18 hours under a nitrogen atmosphere. The reaction solution was then added dropwise to methanol (100 ml), and the resulting precipitate was separated by filtration. The precipitate was washed three times with methanol (100 ml) and dried under reduced pressure to obtain polymer powder p(M-3)-(R-3)-1. The polymer has a Mn of 5100 and a Mw of 5300.

[0193] The raw materials, the types of control agents, and the ratio of control agents to raw materials were replaced with the substances shown in Table 3 below. Otherwise, the same procedure as in Synthesis Example 3-1 was followed to obtain the homopolymer shown in Table 3 below.

[0194] [Table 3] <Synthesis of Polyamic Acid-Polyimide> (Synthesis Example 4-1) In a 100 mL four-necked flask equipped with a mechanical stirrer and a nitrogen inlet tube, DA-1 (0.584 g, 5.40 mmol), DA-2 (1.98 g, 8.10 mmol), DA-3 (2.60 g, 8.10 mmol), and DA-4 (1.84 g, 5.40 mmol) were measured, and NMP (93.73 g) was added. The mixture was stirred under a nitrogen atmosphere until dissolved, and then TC-1 (5.63 g, 25.1 mmol) was added while maintaining the temperature below 10°C using an ice bath. The reaction was carried out at room temperature under a nitrogen atmosphere for 18 hours, resulting in a polyamic acid (PAA-1) solution with a viscosity of approximately 200 mPa·s and a solids content of 12% by mass. The molecular weight of this polyamic acid is Mn: 12600, Mw: 35200.

[0195] (Synthesis Example 4-2) In a 300 mL flask equipped with a stir bar and a nitrogen inlet tube, 40.0 g of the polyamic acid (PAA-1) solution obtained above was measured, NMP (74.3 g) was added, and the mixture was stirred at room temperature for a short time. Then, acetic anhydride (5.61 g: 55.0 mmol) and pyridine (2.90 g, 36.7 mmol) were added. The mixture was stirred at room temperature for 30 minutes under a nitrogen atmosphere, and then reacted at 50 °C for 3 hours under a nitrogen atmosphere. After the reaction was completed, the reaction solution was slowly injected into 500 mL of methanol cooled to below 10 °C while stirring to precipitate the solid. The mixture was stirred for 10 minutes. The precipitate was separated by filtration and washed twice with methanol (200 mL) for a total of 30 minutes each time. The solid was then dried under vacuum at 80 °C to obtain the target polyimide powder (SPI-1) (7.04 g, yield 88%). The polyimide has an imidization rate of 66% and a molecular weight of Mn: 12200 and Mw: 36600.

[0196] (Synthesis Example 4-3) In a 100 mL four-necked flask equipped with a mechanical stirrer and a nitrogen inlet tube, DA-5 (4.83 g, 16.2 mmol) and DA-6 (1.62 g, 10.8 mmol) were measured, and NMP (89.1 g) was added. The mixture was stirred under a nitrogen atmosphere until dissolved, and then TC-2 (5.69 g, 25.4 mmol) was added while maintaining the temperature below 10°C using an ice bath. The reaction was carried out at room temperature for 18 hours, resulting in a polyamic acid (PAA-2) solution with a viscosity of approximately 600 mPa·s and a solids content of 12% by mass. The molecular weight of this polyamic acid is Mn: 17200, Mw: 48200.

[0197] (Synthesis Example 4-4) In a 100 mL four-necked flask equipped with a mechanical stirrer and a nitrogen inlet tube, DA-7 (4.30 g, 21.6 mmol) and DA-8 (1.07 g, 5.40 mmol) were measured, and NMP (81.1 g) was added. The mixture was stirred under a nitrogen atmosphere until dissolved, and then TC-2 (5.69 g, 25.4 mmol) was added while maintaining the temperature below 10°C using an ice bath. The reaction was carried out at room temperature for 18 hours, resulting in a polyamic acid (PAA-3) solution with a viscosity of approximately 720 mPa·s and a solids content of 12% by mass. The molecular weight of this polyamic acid is Mn: 14000, Mw: 38600.

[0198] The contents of the synthesized polyamic acid and polyimide are shown in Table 4.

[0199] [Table 4] <Synthesis of Additives> 1 H-NMR indicates the chemical shift δ (unit: ppm) of the signal measured using a Bruker AVANCE III (500 MHz) Fourier transform superconducting nuclear magnetic resonance (FT-NMR) instrument with tetramethylsilane as the internal standard (split mode, integral value). "s" indicates a singlet, "d" indicates a doublet, "t" indicates a triplet, "q" indicates a tetrat, "m" indicates a multi-peak, "br" indicates a broad peak, "J" indicates the coupling constant, "CDCl3" indicates deuterated chloroform, and "d6-DMSO" indicates deuterated dimethyl sulfoxide. "Me" indicates methyl, and "Et" indicates ethyl.

[0200] (Synthesis Example 5-1) [Chemistry 29] THF (70 g) was added to 4,4′-diaminodiphenylamine (5.0 g, 25.1 mmol) while stirring and cooling in an ice bath at 0 °C. (3-isocyanopropyl)trimethoxysilane (11.6 g, 56.5 mmol) dissolved in THF (10.0 g) was added dropwise to the reaction mixture. After the addition was complete, the mixture was stirred at 25 °C for 20 hours. Stirring was stopped, and the crystals were separated by filtration. Methanol (45 g) was added to the obtained crystals, and the mixture was heated and stirred at 50 °C. After cooling to 25 °C, the filtered crystals were dried to give compound (AD-1) (yield: 12.0 g, 19.7 mmol, 78%).

[0201] 1 H-NMR(500MHz) in d6-DMSO: δ (ppm) = 8.08 (s, 2H), 7.57 (s, 1H), 7.20 (d, J = 8.5Hz, 4H), 6.87 (d, J = 9.0Hz, 4H ), 6.00(t, 2H), 3.48(s, 18H), 3.05-3.01(m, 4H), 1.49-1.45(m, 4H), 0.60-0.56(m, 4H). (Synthesis example 5-2) [Chemistry 30] 1,3-Diaminobenzene (2.16 g, 20.0 mmol) and THF (30 g) were added to a 100 mL four-necked flask. A solution prepared by diluting (3-isocyanopropyl)trimethoxysilane (9.03 g, 44.0 mmol) with THF (5 g) was added dropwise over 1 hour with ice-cold stirring. The mixture was then stirred at room temperature for 18 hours. The precipitated crystals were then filtered and transferred to a separate 300 mL round-bottom flask. Methanol (50 g) was added to the flask, and the mixture was stirred at room temperature for a period of time. The precipitated crystals were then filtered and dried under reduced pressure to obtain compound (AD-2) (yield: 8.30 g, 16.0 mmol, 80%, appearance: white solid).

[0202] 1 H-NMR(500MHz) in d6-DMSO: δ (ppm) = 8.32 (s, 2H), 7.45 (s, 1H), 7.04-6.93 (m, 3H), 6.06 (t, J = 5.4H z, 2H), 3.48 (s, 18H), 3.06-3.02 (m, 4H), 1.50-1.44 (m, 4H), 0.60-0.57 (m, 4H). (Synthesis Example 5-3) [Chemistry 31] 1,3-bis(4-aminophenoxy)propane (2.58 g, 10.0 mmol) and THF (52 g) were added to a 100 mL four-necked flask. A solution prepared by diluting (3-isocyanopropyl)trimethoxysilane (4.52 g, 22.0 mmol) with THF (5 g) was added dropwise over 1 hour with ice-cold stirring. The mixture was then stirred at room temperature for 18 hours. The precipitated crystals were then filtered, and the separated crystals were transferred to a separate 300 mL round-bottom flask. Next, methanol (50 g) was added to the flask, and the mixture was stirred at room temperature for a period of time. The precipitated crystals were then filtered, dried under reduced pressure, and the compound (AD-3) was obtained (yield: 5.55 g, 8.30 mmol, 83%, appearance: white solid).

[0203] 1 H-NMR(500MHz) in d6-DMSO: δ (ppm) = 8.15 (s, 2H), 7.27 (d, J = 8.6Hz, 4H), 6.83 (d, J = 8.7Hz, 4H), 6.03 (t, J = 5.6Hz, 2H), 4.06 ( m, 4H), 3.31ppm (s, 18H), 3.03-3.01 (m, 4H), 2.11 (t, J=6.2Hz, 2H), 1.50-1.43 (m, 4H), 0.59-0.56 (m, 4H). (Synthesis Example 5-4) [Chemistry 32] 4,4′-diaminodiphenylmethane (1.98 g, 10.0 mmol) and THF (40 g) were added to a 100 mL four-necked flask. A solution prepared by diluting (3-isocyanopropyl)trimethoxysilane (4.52 g, 22.0 mmol) with THF (5 g) was added dropwise over 1 hour with stirring at room temperature. The mixture was then stirred for 18 hours at room temperature. The precipitated crystals were then separated by filtration and transferred to a separate 300 mL round-bottom flask. Methanol (50 g) was then added to the flask, and the mixture was stirred for a period of time at room temperature. The precipitated crystals were then separated by filtration and dried under reduced pressure to obtain compound (AD-4) (yield: 5.05 g, 8.30 mmol, 83%, appearance: white solid).

[0204] 1H-NMR(500MHz) in d6-DMSO: δ (ppm) = 8.27 (s, 2H), 7.27 (d, J = 7.9Hz, 4H), 7.03 (d, J = 7.9Hz, 4H), 6.09 (t, J = 5.5H z, 2H), 3.74 (s, 2H), 3.47 (s, 18H), 3.05-3.01 (m, 4H), 1.49-1.43 (m, 4H), 0.60-0.56 (m, 4H). (Synthesis Example 5-5) [Chemistry 33] 4,4′-diaminodiphenyl ether (2.00 g, 10.0 mmol) and THF (40 g) were added to a 100 mL four-necked flask. A solution prepared by diluting (3-isocyanopropyl)trimethoxysilane (4.52 g, 22.0 mmol) with THF (5 g) was added dropwise over 1 hour with stirring at room temperature. The mixture was then stirred for 18 hours at room temperature. The precipitated crystals were then separated by filtration and transferred to a separate 300 mL round-bottom flask. Methanol (50 g) was then added to the flask, and the mixture was stirred for a period of time at room temperature. The precipitated crystals were then separated by filtration and dried under reduced pressure to obtain compound (AD-5) (yield: 5.38 g, 8.80 mmol, 88%, appearance: white solid).

[0205] 1 H-NMR(500MHz) in d6-DMSO: δ (ppm) = 8.32 (s, 2H), 7.35 (d, J = 8.7Hz, 4H), 6.85 (d, J = 8.5Hz, 4H), 6.10 (t, J=5.6Hz, 2H), 3.48(s, 18H), 3.06-3.02(m, 4H), 1.50-1.44(m, 4H), 0.60-0.56(m, 4H). (Synthesis Example 5-6) [Chemistry 34] In a 2L four-necked flask, 20.0 g (100 mmol) of 4,4′-diaminodiphenylamine and 300 g of THF were added dropwise over 30 minutes with ice-cold stirring. A solution of (3-isocyanopropyl)triethoxysilane (50.9 g, 206 mmol) diluted with 100 g of THF was then added dropwise, and the mixture was stirred at room temperature for 18 hours. The reaction solution was then concentrated under reduced pressure, and approximately half of the THF was removed by distillation. Next, 720 g of acetonitrile was added at room temperature, and the mixture was stirred for 30 minutes, followed by stirring at 5°C for a period of time. The precipitated crystals were filtered, separated, and dried under reduced pressure to give compound (AD-6) (yield: 60.7 g, 87.5 mmol, 87% yield, appearance: white solid).

[0206] 1 H-NMR(500MHz) in d6-DMSO: δ (ppm) = 8.10 (s, 2H), 7.61 (s, 1H), 7.20 (d, J = 7.6Hz, 4H), 6.87 (d, J = 7.6Hz, 4H), 6.04-6.00 (m, 2H) , 3.75(q, J=6.8Hz, 12H), , 3.06-3.00(m, 4H), 1.50-1.42(m, 4H), 1.14(t, J=6.8Hz, 18H), 0.58-0.52(m, 4H). <Preparation of Liquid Crystal Alignment Agent> (Preparation Example 1) In a 10 mL tubular flask equipped with a stir bar, 0.600 g of p(M-1) obtained in Synthesis Example 1-1 was measured, 6.40 g of NMP and 3.00 g of BCS were added, and the mixture was stirred at room temperature for 1 hour to obtain liquid crystal alignment agent (AL-1).

[0207] (Preparation Examples 2-38) The polymers used were replaced with those shown in Tables 5-1 and 5-2 below, and the same procedure was followed as in Preparation Example 1, thereby obtaining the strongly anchored liquid crystal alignment agents (AL-2) to (AL-38) shown in Tables 5-1 and 5-2 below.

[0208] [Table 5-1] [Table 5-2] (Preparation Example 39) In a 10 mL tubular flask equipped with a stir bar, 0.600 g of p(M-3) obtained in Synthesis Examples 1-3 was measured, 6.40 g of NMP and 3.00 g of BCS were added, and 0.030 g of AD-1 obtained in Synthesis Example 5-1 was further measured as an additive. The mixture was stirred at room temperature for 1 hour to obtain the liquid crystal alignment agent (AL-39).

[0209] (Preparation Examples 40-44) The additives were replaced with those shown in Table 5-3 below, and the same procedure as in Preparation Example 39 was followed to obtain strongly anchored liquid crystal alignment materials (AL-40 to 44) as shown in Table 5-3 below.

[0210] [Table 5-3] <Substrate Fabrication for In-plane Orientation Parameter Measurement> Using the liquid crystal alignment agent obtained above, a substrate for measuring photoresponse rate was fabricated in the order shown below. A quartz substrate with dimensions of 40 mm × 40 mm and a thickness of 1.0 mm was used as the substrate.

[0211] Using apertures of 1.0 mm respectively μ The liquid crystal alignment agents (AL-1 to AL-38) prepared by the above method are filtered through a filter and then coated onto a quartz substrate using spin coating to form a film. Next, after drying on a hot plate at 70°C for 90 seconds, an alignment process is performed using photo-alignment. In the photo-alignment process, a UV exposure apparatus manufactured by USHIO Electric Co., Ltd. is used, with linearly polarized UV light of approximately 26:1 at a wavelength of 254 nm, and an irradiation dose of 300 mJ / cm². 2 After being irradiated with polarized UV light, the polymer constituting the liquid crystal alignment agent is fired within the liquid crystal temperature range to achieve the alignment process.

[0212] <Determination of in-plane orientation (ΔS)> Using the substrate with the liquid crystal alignment film prepared above, in order to determine the optical anisotropy of the liquid crystal alignment film, ΔS, which is the in-plane alignment degree, is calculated from the absorbance of polarized light using the following formula. The calculated value is the highest value within the irradiation range.

[0213] It should be noted that the absorbance was measured using a Shimadzu U-3100PC ultraviolet-visible-near-infrared analytical photometer manufactured by Shimadzu Corporation.

[0214] [Number 2] Here, A paraA represents the absorbance in the direction parallel to the UV direction of the polarized light being irradiated. per This indicates the absorbance in the direction perpendicular to the UV direction of the polarized light being incident on. A large A represents the absorbance of the direction perpendicular to the light emitted, indicating the value of the larger absorbance value compared to the direction perpendicular to the light emitted. small This indicates the absorbance of the direction parallel to the plane and the direction perpendicular to the plane, with the smaller value indicating the absorbance of the direction parallel to the plane. The closer the absolute value of the in-plane orientation is to 1, the more similar the uniaxial orientation is.

[0215] <Evaluation of the Orientation Characteristics of Various Liquid Crystal Orientation Agents> The contents of the embodiments and the evaluation results are shown in Table 6.

[0216] [Table 6] As shown in Table 6, it can be seen that when using the liquid crystal alignment agents of Examples 1 to 34, the degree of alignment (ΔS) all showed a value of 0.3 or higher, and uniaxial alignment was achieved in the direction perpendicular to the polarizing photoelectric field. On the other hand, it is believed that the reason is that AL-18 and AL-19 (Comparative Examples 1 and 2), which do not have benzoic acid groups at the end of their side chains, only exhibit anisotropy with an alignment degree of less than 0.15, and do not have benzoic acid groups that function as photosensitive sites for 254nm light. In addition, according to Comparative Examples 3 and 4 and Reference Example 1, it is believed that when AL-20 and AL-28, which have cinnamic acid structures at the end of their side chains, are also used with 254nm light, only anisotropy with an alignment degree of less than 0.15 is obtained, and the photoreaction of cinnamic acid hinders alignment. In addition, according to Reference Example 2, even AL-3, which has benzoic acid groups at the end, cannot obtain anisotropy under ultraviolet light exposure at 313nm. Therefore, it can be seen that the liquid crystal alignment agent of the present invention is a polymer with benzoic acid groups at the end of the side chain, and does not have a cinnamic acid structure. It functions as a liquid crystal alignment agent by exposure to 254nm polarized ultraviolet light.

[0217] As can be seen from Examples 31 to 34, even when polyamic acid and soluble polyimide are mixed as the second polymer, good orientation is exhibited. As long as the polymer with benzoic acid groups on the side chain is included, there can be two or more components.

[0218] <Evaluation Methods for Lightfastness> Using the substrate with the liquid crystal alignment film prepared above, in order to measure the light-gathering property of the liquid crystal alignment film, a high-brightness backlight (light source: LED, brightness: 27000 cd / m²) was applied. 2 The material is aged for any time, and the orientation degree (ΔS) is measured at each time point for evaluation. The better the lightfastness of the material, the smaller the change in orientation degree; the worse the lightfastness of the material, the greater the increase or decrease in orientation degree with aging time.

[0219] It should be noted that the absorbance was measured using a Shimadzu U-3100PC ultraviolet-visible-near-infrared analytical photometer manufactured by Shimadzu Corporation.

[0220] <Evaluation of the lightfastness of various liquid crystal alignment films> The contents of the embodiments and the evaluation results are shown in Table 7.

[0221] [Table 7] As shown in Table 7, when using the liquid crystal alignment agents of Examples 35-38, the degree of alignment (ΔS) remained approximately constant regardless of the curing time. On the other hand, AL-20 (Comparative Example 5), which has a cinnamic acid structure in its side chain, showed a significant decrease in alignment degree with curing time. It is speculated that this is because the short-wavelength components in the backlight induce photoreactions in the photosensitive side chains of the liquid crystal alignment film, leading to orientation disorder.

[0222] <Fabrication of FFS-driven LCD cells> To manufacture a liquid crystal unit consisting of an FFS mode liquid crystal display element.

[0223] First, a substrate with electrodes is prepared. A rectangular glass substrate measuring 30mm × 35mm with a thickness of 0.7mm is used. An ITO electrode with a full-surface pattern, constituting a common electrode, is formed on the substrate as the first layer. A SiN (silicon nitride) film, deposited by CVD (chemical vapor deposition), is formed on the common electrode of the first layer as the second layer. The SiN film of the second layer has a thickness of 300nm, which is sufficient to function as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning the ITO film is disposed as the third layer, forming two pixels: a first pixel and a second pixel. Each pixel has dimensions of 10mm in length and 5mm in width. This electrode-equipped substrate has a structure where the common electrode of the first layer and the pixel electrode of the third layer are insulated by the SiN film of the second layer.

[0224] The third layer of pixel electrodes has a central portion that bends at an inner angle of 160° and multiple electrodes with a width of 3... μ The electrode wire is 6 m in length. μ The comb-like shape is arranged in parallel at intervals of m. Each pixel is formed by multiple electrode lines, and has a first region and a second region bounded by the line connecting the bends.

[0225] Next, using an aperture of 1.0 μ After filtering the obtained liquid crystal alignment agent through a filter of m, it is then coated by spin coating onto the electrode substrate (hereinafter referred to as the electrode substrate) and the substrate with an ITO film deposited on the back side, having a height of 4. μA 100 nm thick coating is formed by drying a columnar spacer on a glass substrate (hereinafter referred to as the opposing substrate) at 80 °C for 2 minutes. The coating surface is then subjected to a pressure of 1000 mJ / cm². 2 The substrate is irradiated with polarized ultraviolet light through a 254nm bandpass filter and a polarizer, and then fired in an IR oven at 120°C for 30 minutes to perform alignment treatment, resulting in a substrate with a liquid crystal alignment film. It should be noted that the liquid crystal alignment film formed on the electrode substrate is aligned such that the direction dividing the inner angle of the pixel bend is orthogonal to the alignment direction of the liquid crystal, and the alignment film formed on the opposing substrate is aligned such that the alignment direction of the liquid crystal on the electrode substrate is consistent with the alignment direction of the liquid crystal on the opposing substrate during the fabrication of the liquid crystal cell. The two substrates are grouped together, and a sealant (Mitsui Chemicals XN-1500T) is printed onto the substrates using a distributor. Another substrate is then bonded together with its respective liquid crystal alignment film aligned at 0°. The bonded substrates are then pressed together and heated in a hot air circulating oven at 120°C for 90 minutes to cure the sealant, thus creating an empty cell. Positive liquid crystal MLC-3019 (manufactured by Merck) was injected into the empty cell using a depressurized injection method, and the injection port was sealed, thereby obtaining an FFS-driven liquid crystal cell. Subsequently, the obtained liquid crystal cell was heated at 120°C for 1 hour and then left at 23°C overnight for evaluation.

[0226] <Evaluation of the stability of liquid crystal alignment> This evaluation assesses image retention (also known as AC image retention) caused by the deterioration of the alignment performance of the liquid crystal alignment film during long-term AC driving. For the aforementioned FFS-driven liquid crystal cell, an AC voltage of ±4V at a frequency of 60Hz was applied for 120 hours at a constant temperature of 60°C. Afterward, the pixel electrode and common electrode of the liquid crystal cell were short-circuited, and the cell was left at room temperature (23°C) for one day. For the liquid crystal cell subjected to the above treatment, the difference between the alignment direction of the liquid crystal in the first region of the pixel and the alignment direction of the liquid crystal in the second region of the pixel under no-voltage applied state was calculated as the angle. Specifically, the liquid crystal cell was placed between two polarizers arranged orthogonally to the polarization axes. With the backlight illuminated, the arrangement angle of the liquid crystal cell was adjusted to minimize the transmitted light intensity in the first region of the first pixel. Then, the rotation angle required to rotate the liquid crystal cell to minimize the transmitted light intensity in the second region of the first pixel was calculated as the angle Δ. The same angle Δ was calculated for the first and second regions in the second pixel. Finally, the average angle Δ of the first and second pixels was calculated as the rotation angle Δ of the liquid crystal cell. The smaller the value of the rotation angle Δ, the better the stability of the liquid crystal alignment. As an evaluation criterion, cases where the rotation angle Δ of the liquid crystal cell obtained above is less than 0.15° are set as "excellent", cases where it is greater than 0.15° but less than 0.25° are set as "good", and cases where it is greater than 0.25° are set as "poor".

[0227] <Evaluation of Voltage Holding Rate> A voltage of 1V is applied to the liquid crystal cell manufactured in the above sequence at a temperature of 60°C. μ The voltage was measured after 1000 ms, and the voltage retention rate was calculated as the percentage that the voltage could be maintained. The voltage retention rate was measured using a VHR-1 manufactured by Toyo Teknica Co., Ltd. It should be noted that a higher voltage retention rate is better. A voltage retention rate of 95% or higher was defined as "Excellent," less than 95% but more than 90% as "Good," less than 90% but more than 85% as "Acceptable," and less than 85% as "Unacceptable."

[0228] <Evaluation results of cell characteristics for each liquid crystal cell> The contents of the embodiments and the evaluation results are shown in Table 8.

[0229] [Table 8] As shown in Table 8, the liquid crystal cells obtained in Examples 39-45 all exhibited good liquid crystal alignment stability. Furthermore, the liquid crystal cells obtained in Examples 40-45, which used additives AD-1-6, showed excellent voltage retention.

[0230] Explanation of reference numerals in the attached figures 1. Lateral electric field liquid crystal display element 2. Comb-shaped electrode substrate 2a Substrate 2b Wire electrode 2c liquid crystal alignment film 2D substrate 2e surface electrode 2f insulating film 2g linear electrode 2h liquid crystal alignment film 3 LCD 4 Opposite substrates 4a Liquid crystal alignment film 4b Substrate L represents electric field lines.

Claims

1. A method for manufacturing a liquid crystal alignment film, characterized in that, The liquid crystal alignment film is obtained through the following process: A process of exposing an organic film having a polymer P to polarized ultraviolet light of a wavelength of 254 nm, wherein the polymer P is obtained by polymerization of a monomeric component comprising a polymeric unsaturated hydrocarbon group of a polymeric compound represented by formula (1) below, wherein the proportion of light at wavelength 254 nm is 90% or more relative to the total amount of light at wavelengths of 254 nm, 313 nm, and 365 nm contained in the polarized ultraviolet light; and The heating process is performed at the liquid crystal performance temperature of the polymer. In equation (1), n ​​is 0, 1, 2 or 3, and m is 1 or 2. L is a single bond, an alkylene group having 1 to 12 carbon atoms, or a divalent linker consisting of one or more -CH2- groups of an alkylene group having 1 to 12 carbon atoms, each independently replaced by -O-, -S-, -C(=O)-O-, or -OC(=O)-, wherein some or all of the hydrogen atoms of the alkylene group and the divalent linker are replaced by halogen atoms or not. A can be a single bond, -O-, -CH2-, -C(=O)-O-, -OC(=O)-, -C(=O)-NH-, or -NH-C(=O)-. Y is phenylene or naphthylene, wherein some or all of the hydrogen atoms of the phenylene and naphthylene groups are replaced by or not replaced by a cyano group, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkyl carbonyl group having 2 to 6 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. Q is a single bond, a phenylene group, or a divalent alicyclic hydrocarbon group with 5 to 8 carbon atoms, wherein some or all of the hydrogen atoms of the phenylene group are replaced by or not replaced by a cyano group, a halogen atom, an alkyl group with 1 to 5 carbon atoms, an alkyl carbonyl group with 2 to 6 carbon atoms, or an alkoxy group with 1 to 5 carbon atoms. X is a single bond, -O-, -C(=O)-O-, -OC(=O-), -N=N-, -CH=CH-, -C≡C-, -CH=CH-C(=O)-O-, or -OC(=O)-CH=CH-. When the number of L, A, Y, Q, and X is 2 or more, each L, A, Y, Q, and X may be the same as or different from the others. M is a polymerizable unsaturated hydrocarbon group.

2. The manufacturing method according to claim 1, wherein, The polymer P is a polymer composed of liquid crystal units that have a large absorption peak only in the wavelength region below 330 nm.

3. The manufacturing method according to claim 1, wherein, The polymer P is a polymer that exhibits nematic liquid crystal properties or smectic liquid crystal properties in the temperature range of 90 to 200°C.

4. The manufacturing method according to claim 1, wherein, In the above equation (1), M is represented by any of the following: In the formula, R1 and R2 each independently represent a hydrogen atom or a straight-chain or branched alkyl group having 1 to 12 carbon atoms, and E, T, and G each independently represent an oxygen atom or a sulfur atom. , 1 and 2 Indicates the bonding site. 1 and 2 Any one of them may or may not be replaced by a hydrogen atom or a straight-chain or branched alkyl group having 1 to 12 carbon atoms.

5. The manufacturing method according to claim 1, wherein, The liquid crystal alignment agent used to form the organic film also includes a compound having an alkoxysilyl group and a urea structure with substituted 1- and 3-positions.

6. A method for manufacturing a liquid crystal display element, characterized in that, include: A process for manufacturing a substrate having a liquid crystal alignment film obtained by any one of claims 1 to 5.

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