Liquid crystal alignment agent, liquid crystal alignment film and method for manufacturing the same, and liquid crystal element

Abstract

To provide a liquid crystal alignment agent capable of obtaining a liquid crystal alignment film which is high in rubbing resistance and excellent in low pre-tilt angle characteristic and obtaining a liquid crystal element in which liquid crystal has high response speed, low driving voltage and high transmittance.SOLUTION: The liquid crystal alignment agent contains: polymer (P) having a partial structure configured by removing one or more hydrogen atoms from a ring part in the structure of formula (1); and compound (A) including, in one molecule, total two or more pieces of at least one type selected from a group consisting of oxiranyl group, oxetanyl group, cyclic carbonate group, hydroxy group, protected hydroxy group, mercapto group, protected mercapto group, amino group, protected amino group, protected isothiocyanate group and polymerizable carbon-carbon unsaturated bond group, and including no aromatic ring. Ar1 and Ar2 represents divalent aromatic ring group. X1 represents single bond, oxygen atom, -NR1-, and the like. X2 represents -NR1- or C1-3 alkanediyl group.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Liquid crystal elements are used in a wide range of applications as a basic structure that exhibits required functions by controlling the orientation of liquid crystal molecules. In such liquid crystal elements, the orientation of liquid crystal molecules in the liquid crystal cell is controlled by a liquid crystal alignment film formed on a substrate. Conventional methods for obtaining organic films with liquid crystal alignment regulating power include rubbing treatment of organic films formed using polymer compositions, oblique deposition of silicon dioxide, forming monolayers having long-chain alkyl groups, and irradiating photosensitive organic films with light (photo-alignment method).

[0003] The rubbing method is simple and produces good orientation of liquid crystal molecules, and is therefore still widely used industrially. On the other hand, the rubbing method is prone to abrasion and scratching of the film surface during the rubbing process, and there are concerns that this abrasion and scratching of the film surface may degrade the performance of the liquid crystal element. Therefore, various studies have been conducted to obtain a liquid crystal alignment film that exhibits less abrasion and scratching of the film surface during the rubbing process (excellent rubbing resistance) (see, for example, Patent Document 1). Patent Document 1 discloses a polyimide precursor obtained using a diamine having a urea bond, or a liquid crystal alignment agent containing a polyimide. Furthermore, in order to obtain a liquid crystal alignment film with high mechanical strength, a crosslinking agent is sometimes incorporated into the liquid crystal alignment agent together with the polymer component (see, for example, Patent Document 2). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2010 / 53128 [Patent Document 2] International Publication No. 2010 / 074269 [Overview of the project] [Problems that the invention aims to solve]

[0005] From the perspective of improving viewing angle characteristics, in recent years there has been a demand for characteristics that orient liquid crystal molecules at a lower pre-tilt angle than conventional methods (hereinafter also referred to as "low pre-tilt angle characteristics"). However, there is a trade-off relationship between low pre-tilt angle characteristics and rubbing resistance. When attempting to increase the mechanical strength of an organic film obtained using a liquid crystal alignment agent by adding a crosslinking agent to the liquid crystal alignment agent in order to improve its rubbing resistance, the pre-tilt angle tends to increase.

[0006] Furthermore, with the expansion of liquid crystal elements' applications, the demand for higher quality liquid crystal elements has increased. One way to achieve this is to improve performance by further increasing the response speed of the liquid crystal. However, liquid crystal alignment films with superior liquid crystal alignment control capabilities increase the resistance acting on the liquid crystal during driving, and there are concerns that the driving voltage of the liquid crystal element will increase as the response speed of the liquid crystal increases. In addition, in applications where transparency is required for liquid crystal elements, high transmittance of the liquid crystal element is also required.

[0007] The present invention has been made in view of the above circumstances, and one of its objectives is to provide a liquid crystal alignment agent that can obtain a liquid crystal alignment film with high rubbing resistance and good low pre-tilt angle characteristics, as well as a liquid crystal element with a fast liquid crystal response speed, low driving voltage, and high transmittance. [Means for solving the problem]

[0008] According to the present invention, the following means are provided. [1] A liquid crystal alignment agent comprising: a polymer (P) having a substructure composed of removing one or more hydrogen atoms from the ring portion of the structure represented by (1) (except for the fluorene ring in the 9-fluorenylmethyloxycarbonyl group); and a compound (A) having a total of two or more of at least one selected from the group consisting of an oxiranyl group, an oxetanyl group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, a protected isocyanate group, and a polymerizable carbon-carbon unsaturated bond group in one molecule, and having no aromatic ring. [ka] (In formula (1), Ar 1 and Ar 2 These are independently divalent aromatic ring groups. 1 It consists of a single bond, an oxygen atom, a sulfur atom, and -NR. 1 -or an alkanediyl group having 1 to 3 carbon atoms. 2 -NR 1 -or an alkanediyl group having 1 to 3 carbon atoms. 1 (This is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally desorbable group.)

[0009] [2] A method for manufacturing a liquid crystal alignment film, comprising the steps of forming a coating film using the liquid crystal alignment agent described in [1] above, and subjecting the coating film to a rubbing treatment to impart liquid crystal alignment ability. [3] A liquid crystal alignment film formed with the liquid crystal alignment agent described in [1] above. [4] A liquid crystal element comprising the liquid crystal alignment film described in [3] above. [Effects of the Invention]

[0010] According to the liquid crystal alignment agent of the present invention, a liquid crystal alignment film with high rubbing resistance and good low pre-tilt angle characteristics can be obtained. Furthermore, a liquid crystal element with a fast liquid crystal response speed, low driving voltage, and high transmittance can be obtained. [Modes for carrying out the invention]

[0011] Liquid crystal alignment agent The liquid crystal alignment agent of this disclosure contains a polymer (P) having a specific aromatic condensed ring structure and a compound (A) having a total of two or more specific functional groups exhibiting crosslinkability in one molecule. The liquid crystal alignment agent of this disclosure may also optionally contain components other than polymer (P) and compound (A). The following describes each component contained in the liquid crystal alignment agent of this disclosure, as well as optionally added components (hereinafter also referred to as "other components").

[0012] Herein, in this specification, "hydrocarbon group" means a group of hydrocarbons including linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Linear hydrocarbon group" means a linear hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure in its main chain and consists only of a linear structure. However, linear hydrocarbon groups may be saturated or unsaturated. "Alicyclic hydrocarbon group" means a hydrocarbon group that contains only the structure of an alicyclic hydrocarbon as its ring structure and does not contain an aromatic ring structure. However, an alicyclic hydrocarbon group does not have to consist only of the structure of an alicyclic hydrocarbon, and may also include a linear structure as part of it. "Aromatic hydrocarbon group" means a hydrocarbon group that contains an aromatic ring structure as its ring structure. However, an aromatic hydrocarbon group does not have to consist only of an aromatic ring structure, and may include a linear structure or an alicyclic hydrocarbon structure as part of it. "Aromatic ring" means an aromatic hydrocarbon ring and an aromatic heterocycle. "Organic group" means an atomic group obtained by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound).

[0013] The "main chain" of a polymer refers to the "trunk" portion of the polymer, which consists of the longest chain of atoms. This "trunk" portion may contain a ring structure. For example, "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. "Side chains" refer to the parts of a polymer that branch off from the "trunk" portion. "(meth)acrylic" is a term that encompasses acrylic and methacrylic, and "(meth)acrylo" is a term that encompasses acrylo and methacrylo. "(meth)acrylate" is a term that encompasses acrylate and methacrylate.

[0014] <Polymer (P)> The polymer (P) has a partial structure (hereinafter also referred to as "partial structure (X)") formed by removing one or more hydrogen atoms from the ring part in the structure represented by the following formula (1) (excluding the fluorene ring in the 9-fluorenylmethyloxycarbonyl group). [Chemical formula] (In formula (1), Ar 1 and Ar 2 are each independently a divalent aromatic ring group. X 1 is a single bond, an oxygen atom, a sulfur atom, -NR 1 -, or an alkanediyl group having 1 to 3 carbon atoms. X 2 is -NR 1 - or an alkanediyl group having 1 to 3 carbon atoms. R 1 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally desorbable group.)

[0015] The liquid crystal alignment film obtained by rubbing the film containing the polymer (P) has the alignment direction of the liquid crystal molecules perpendicular to the rubbing direction, and thereby the pretilt angle becomes a small value of 0 degrees or more and less than 0.3 degrees. In general, the liquid crystal alignment film made of a polyamic acid having no partial structure (X) has the liquid crystal molecules aligned in the same direction as the rubbing direction, and the pretilt angle is 1 degree or more.

[0016] In the above formula (1), Ar 1 or Ar 2The divalent aromatic ring group represented by is a group obtained by removing two hydrogen atoms from the ring portion of a substituted or unsubstituted aromatic ring. The aromatic ring may be an aromatic hydrocarbon ring or an aromatic heterocycle. Specific examples of aromatic hydrocarbon rings include benzene rings, naphthalene rings, and anthracene rings. Examples of aromatic heterocycles include nitrogen-containing aromatic heterocycles, oxygen-containing aromatic heterocycles, and sulfur-containing aromatic heterocycles. Specific examples of these include pyridine rings, pyrimidine rings, pyridazine rings, and pyrazine rings as nitrogen-containing aromatic heterocycles; furan rings as oxygen-containing aromatic heterocycles; and thiophene rings as sulfur-containing aromatic heterocycles. When an aromatic ring group has substituents on its ring portion, examples of such substituents include C1-C10 alkyl groups, C1-C10 alkoxy groups, C3-C12 cycloalkyl groups, C6-C12 aryl groups, C7-C13 aralkyl groups, halogen atoms, C1-C10 halogenated alkyl groups, hydroxyl groups, and the like.

[0017] This composition offers several advantages: it can improve the liquid crystal alignment properties of the liquid crystal alignment film obtained, it can increase the refractive index of the liquid crystal alignment film while maintaining a high transmittance, and the polymer (P) is easy to manufacture. 1 and Ar 2 Preferably, the group is obtained by removing two hydrogen atoms from the ring portion of a substituted or unsubstituted benzene ring or naphthalene ring, and more preferably, it is obtained by removing two hydrogen atoms from the ring portion of a substituted or unsubstituted benzene ring.

[0018] Generally, liquid crystal cells have a structure in which three layers are stacked: an electrode (e.g., an ITO electrode), a liquid crystal alignment film, and a liquid crystal layer. It is thought that light reflection occurs at each interface of these three layers, leading to a decrease in the transmittance of the liquid crystal cell. Furthermore, the refractive index of a liquid crystal alignment film made of polyamic acid without a substructure (X) is generally close to that of liquid crystal (1.5 to 1.6), and the refractive index difference between it and the refractive index of the ITO electrode (approximately 2 ± 0.2) is relatively large. In this regard, the present composition makes it possible to increase the refractive index of the liquid crystal alignment film, bringing the refractive index of the liquid crystal alignment film closer to that of the ITO electrode compared to a liquid crystal alignment film made of polyamic acid without a substructure (X), within the range from the refractive index of the ITO electrode (approximately 2 ± 0.2) to the refractive index of liquid crystal (approximately 1.5 ± 0.1). Moreover, by increasing the refractive index of the liquid crystal alignment film while maintaining a high transmittance of the liquid crystal alignment film, it is possible to achieve even higher transmittance of the liquid crystal cell.

[0019] X 1 or X 2 ga-NR 1 -and R 1 If R is a thermally leaving group, 1 It is a monovalent group that is removed by heat and replaced by a hydrogen atom. Its high thermal removal capability is a key characteristic of R 1 The thermally detachable group represented is preferably a tert-butoxycarbonyl group (Boc group).

[0020] Specific examples of the structure represented by formula (1) above include the structures represented by formulas (r1-1) to (r1-12) below, and structures in which substituents are introduced into these structures. [ka]

[0021] Substructure (X) is a group obtained by removing an arbitrary hydrogen atom from the ring portion of the structure represented by formula (1) above. The position and number of hydrogen atoms removed from the ring portion are not particularly limited. Preferred specific examples of substructure (X) include the substructure represented by formula (1-1) or formula (1-2) below. The polymer (P) preferably has at least one substructure (X) selected from the group consisting of the substructure represented by formula (1-1) and the substructure represented by formula (1-2) below. [ka] (In equations (1-1) and (1-2), Ar 1 Ar 2 and X 1 This is equivalent to equation (1) above. Y 1 This is either a nitrogen atom, or a trivalent group in which a hydrogen atom, methyl group, or hydroxyl group is bonded to a carbon atom. (* indicates a bond.)

[0022] Specific examples of the substructure represented by formula (1-1) above include the substructures represented by formulas (1-1-1) to (1-1-6) below, and substructures in which substituents are introduced to these substructures. Specific examples of the substructure represented by formula (1-2) above include the substructures represented by formulas (1-2-1) to (1-2-14) below. [ka] [ka]

[0023] Furthermore, the substructure (X) does not detach due to heating during film formation and remains bonded to the polymer (P) after the formation of the liquid crystal alignment film. From the viewpoint of increasing the transmittance of the liquid crystal cell and providing a liquid crystal cell that exhibits low pre-tilt angle characteristics and good liquid crystal alignment, while ensuring that the force constraining the orientation of liquid crystal molecules at the interface between the liquid crystal alignment film and the liquid crystal layer (also called the anchoring force) is sufficiently weakened compared to cases where a polymer with the substructure (X) is not used, it is preferable that the substructure (X) of the polymer (P) does not detach at temperatures below 200°C, and more preferably does not detach at temperatures below 230°C.

[0024] The polymer (P) preferably contains 15 mol% or more of structural units having a substructure (X) relative to the total structural units constituting the polymer (P). With such a polymer (P), it is possible to improve the low pretilt angle characteristics and liquid crystal alignment of the liquid crystal element while increasing the transmittance of the liquid crystal cell, and to weaken the anchoring force of liquid crystal molecules present at the interface between the liquid crystal alignment film and the liquid crystal layer (i.e., to achieve a weak anchoring force). From this viewpoint, the content of structural units having a substructure (X) in the polymer (P) is more preferably 20 mol% or more, even more preferably 30 mol% or more, even more preferably 40 mol% or more, and particularly preferably 50 mol% or more, relative to the total structural units constituting the polymer (P). In this specification, "structural unit" refers to a unit that mainly constitutes the main chain structure, and is a chemical structural unit that contains at least two or more in the main chain structure.

[0025] Here, the difference between "weak anchoring force" and "strong anchoring force" lies in the difference in the orientation constraint force that restrains the orientation direction of liquid crystal molecules. That is, in a liquid crystal cell, when the orientation of liquid crystal molecules near the alignment film is controlled by a strong anchoring force, when an electric field is applied, the liquid crystal molecules at the interface between the liquid crystal layer and the liquid crystal alignment film maintain their orientation direction before the application of the electric field, while still being subjected to the orientation constraint force by the liquid crystal alignment film. In contrast, when the orientation of liquid crystal molecules near the alignment film is controlled by a weak anchoring force, the orientation constraint force on the liquid crystal molecules at the interface between the liquid crystal layer and the liquid crystal alignment film is weak, and the orientation direction of the liquid crystal molecules is easily changed when an electric field is applied. Furthermore, by making the liquid crystal alignment film weaker, the orientation constraint force on liquid crystal molecules in that liquid crystal alignment film decreases not only in the horizontal direction but also in the vertical direction. A liquid crystal alignment film formed using a polymer having a substructure (X) (i.e., polymer (P)) yields a liquid crystal alignment film with a weaker anchoring force compared to a liquid crystal alignment film that does not contain a polymer having a substructure (X). This suggests that in liquid crystal cells equipped with a liquid crystal alignment film formed using polymer (P), it may be possible to reduce the voltage used to drive the liquid crystal molecules.

[0026] The main chain of polymer (P) is not particularly limited. From the viewpoint of obtaining a liquid crystal alignment film with excellent liquid crystal alignment and transmittance characteristics, polymer (P) is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyether, polyester, and addition polymer. Polymer (P) may have a substructure (X) in the main chain or in the side chain. Each polymer will be described below.

[0027] (Polyamic acid, polyamic acid esters, and polyimides) When polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, it is preferable that polymer (P) has at least one selected from the group consisting of a substructure represented by the following formula (1-1A) and a substructure represented by the following formula (1-2A). [ka] (In equations (1-1A) and (1-2A), A 1 and A 2 is, A 1 is an (n1+1) valent aromatic ring group and A 2 is an (n2+1) valent aromatic ring group, or A 1 and A 2 Each of these has an aromatic ring, and these aromatic rings are bonded by a single bond, an oxygen atom, a sulfur atom, and -NR 1 -Alternatively, it represents a fused ring structure formed by linking each other with alkanediyl groups having 1 to 3 carbon atoms. 3 Y is an aromatic ring group with (n3+1) valency. 1 n1 is a nitrogen atom, or a trivalent group in which a hydrogen atom, methyl group, or hydroxyl group is bonded to a carbon atom. n1, n2, and n3 are independently 1 or 2. 1 Ar 2 , R 1 and X 1 This is equivalent to equation (1) above. "*" represents a bond.

[0028] In the above equation (1-1A), A 1 Or A 2 If it is an aromatic ring group, the aromatic ring constituting the aromatic ring group may be a monoring or a fused ring. 1 Or A 2 The aromatic ring possessed by is preferably an aromatic hydrocarbon ring, such as a benzene ring, naphthalene ring, indene ring, anthracene ring, phenanthrene ring, etc. Of these, A 1 and A 2 The aromatic ring constituting it is preferably a benzene ring or a naphthalene ring, with a benzene ring being more preferable. A 1 Or A 2 The aromatic ring group represented by may have substituents on the aromatic ring portion. Examples of substituents include Ar 1 Or Ar 2 Examples of substituents that may be present in the ring portion of the divalent aromatic ring group represented by the formula are similar to those exemplified. A 1 and A 2Each of these has an aromatic ring, and these aromatic rings are bonded by a single bond, an oxygen atom, a sulfur atom, and -NR 1 - Alternatively, fused ring structures formed by linking each other with alkanediyl groups having 1 to 3 carbon atoms include fluorene ring structures, tetrahydroanthracene ring structures, xanthene ring structures, and thioxanthene ring structures. Of these, fluorene ring structures or xanthene ring structures are preferred.

[0029] n1 and n2 are either 1 or 2, respectively. Note that if n1 is 1, A 1 is a divalent group, and when n1 is 2, A 1 is a trivalent group. Similarly, when n2 is 1, A 2 is a divalent group, and when n2 is 2, A 2 It is a trivalent group. Ar 1 Ar 2 and X 1 For specific and preferred examples, the explanation of formula (1) above applies.

[0030] In the above equation (1-2A), A 3 The aromatic ring contained in the aromatic ring group represented by may be a monoring or a fused ring. 3 For specific and preferred examples of aromatic rings possessed by A 1 and A 2 The description of the aromatic rings that make up Ar 1 Ar 2 and X 1 For specific and preferred examples, the explanation of formula (1) above applies.

[0031] When polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, polymer (P) can be obtained by [I] a method using a tetracarboxylic dianhydride having substructure (X) (hereinafter also referred to as "specific acid dianhydride"), [II] a method using a diamine having substructure (X) (hereinafter also referred to as "specific diamine"), or a method combining method [I] and method [II].

[0032] (Polyamic acid) Polyamic acid (hereinafter also referred to as "polyamic acid (P)") as a polymer (P) can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound.

[0033] • Tetracarboxylic acid dianhydride In the synthesis of polyamic acid (P), a tetracarboxylic dianhydride having the substructure represented by the above formula (1-1A) can be preferably used as the specific acid dianhydride. By using a tetracarboxylic dianhydride having the substructure represented by the above formula (1-1A) as the specific acid dianhydride, a polymer (P) can be obtained that contains structural units derived from the tetracarboxylic dianhydride having the substructure represented by the above formula (1-1A).

[0034] Preferred specific examples of specific acidic dianhydrides include compounds represented by the following formula (T1) as compounds in which n1 and n2 in the above formula (1-1A) are 1, and compounds represented by the following formula (T2) as compounds in which n1 and n2 in the above formula (1-1A) are 2. [ka] (In equations (T1) and (T2), Ar 1 Ar 2 , X 1 , A 1 and A 2 This is equivalent to equations (1-1A) and (1-2A) above. X 3 and X 4 These are independent of each other, and are single bonds, -O-, -S-, -CO-, -COO-, -NR 20 -,-CO-NR 20 -, -NR 20 -CO-O-, -NR 20 -CO-NR 21 -,-CO-NR 20 -NR 21-, -SO2-O-, -SO2-, an alkane diyl group having 1 to 6 carbon atoms, or a part of methylene groups in an alkane diyl group having 2 to 6 carbon atoms being -O-, -S-, -CO-, -COO-, -NR 20 -, -CO-NR 20 -, -NR 20 -CO-O-, -NR 20 -CO-NR 21 -, -CO-NR 20 -NR 21 -, a divalent group replaced by -SO2-O- or -SO2-. R 20 and R 21 are, independently of each other, a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

[0035] Further specific examples of the specific acid dianhydride include compounds represented by the following formulas (t-1) to (t-4) and the like.

Chemical formula

[0036] In the synthesis of the polyamic acid (P), a tetracarboxylic dianhydride having no partial structure (X) (hereinafter, also referred to as "other acid dianhydride") may be used alone or together with the specific acid dianhydride. Examples of the other acid dianhydride include aliphatic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides. The aliphatic tetracarboxylic dianhydride includes chain tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides.

[0037] Specific examples of linear tetracarboxylic dianhydrides include, for example, butanetetracarboxylic dianhydride. Specific examples of alicyclic tetracarboxylic dianhydrides include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, and 3-oxabicyclo [3.2.1] Octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, bicyclo[3.3.0] Octane-2,4,6,8-tetracarboxylic acid 2:4,6:8-dianhydride, bicyclo[2.2.1] Heptane-2,3,5,6-tetracarboxylic acid 2:3,5:6-dianhydride, 4,9-dioxatricyclo[5.3.1.0 2,6 Examples include undecane-3,5,8,10-tetraone, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, bicyclo[2.2.2]octo-7-ene-2,3,5,6-tetracarboxylic dianhydride, ethylenediaminetetraacetic acid dianhydride, and cyclopentanetetracarboxylic dianhydride.

[0038] Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, p-phenylenebis(trimellitic monoester anhydride), ethylene glycol bis(anhydrotrimellitate), 1,3-propylene glycol bis(anhydrotrimellitate), 3,3',4,4'-benzophenone tetracarboxylic dianhydride, and 4,4'-biphthalic dianhydride. In addition to the above, tetracarboxylic dianhydrides described in Japanese Patent Publication No. 2010-97188 can be used as tetracarboxylic dianhydrides for the synthesis of polyamic acid (P).

[0039] When the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, from the viewpoint of the solubility of the polymer (P) and the formation of an organic film with excellent rubbing resistance, it is preferable that at least a portion of the tetracarboxylic dianhydride used in the synthesis of the polymer (P) be an aliphatic tetracarboxylic dianhydride, and more preferably that it includes an alicyclic tetracarboxylic dianhydride.

[0040] When using specific acid dianhydrides in the synthesis of polyamic acid (P), the proportion of the specific acid dianhydride used is preferably 5 mol% or more, more preferably 20 mol% or more, and even more preferably 40 mol% or more, relative to the total amount of tetracarboxylic dianhydrides used in the synthesis of polyamic acid (P). Note that when synthesizing polyamic acid (P), one type of tetracarboxylic dianhydride may be used alone, or two or more types may be used in combination. The blending ratio of monomers used in the synthesis of the polymer is equivalent to the ratio of monomer units constituting the resulting polymer.

[0041] Furthermore, the proportion of alicyclic tetracarboxylic dianhydride used is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more, relative to the total amount of tetracarboxylic dianhydride used in the synthesis of polyamic acid (P). Note that by using alicyclic tetracarboxylic dianhydride as a monomer in the synthesis of polymer (P), a polymer containing structural units derived from alicyclic tetracarboxylic dianhydride can be obtained as polymer (P).

[0042] • Diamine compounds In the synthesis of polyamic acid (P), it is preferable to use at least one specific diamine selected from the group consisting of diamines having a substructure represented by formula (1-1A) and diamines having a substructure represented by formula (1-2A) as the specific diamine. By using at least one specific diamine selected from the group consisting of diamines having a substructure represented by formula (1-1A) and diamines having a substructure represented by formula (1-2A), it is possible to obtain a polymer (P) that contains structural units derived from at least one specific diamine selected from the group consisting of diamines having a substructure represented by formula (1-1A) and diamines having a substructure represented by formula (1-2A).

[0043] Preferred specific examples of the specific diamine include compounds in formula (1-1A) where n1 and n2 are 1, and compounds in formula (1-2A) where n3 is 1. Preferred specific examples of the compound in formula (1-1A) where n1 and n2 are 1 include compounds represented by the following formula (D1), and preferred specific examples of the compound in formula (1-2A) where n1 and n2 are 1 include compounds represented by the following formula (D2). [ka] (In equations (D1) and (D2), Ar 1 Ar 2 , X 1 , A 1 , A2 and Y 1 is synonymous with the above formula (1-1A) and formula (1-2A). X 5 and X 6 are, independently of each other, a single bond, -O-, -S-, -CO-, -COO-, -NR 22 -, -CO-NR 22 -, -NR 22 -CO-O-, -NR 22 -CO-NR 23 -, -CO-NR 22 -NR 23 -, -SO2-O-, -SO2-, an alkanediyl group having 1 to 6 carbon atoms, or a part of methylene groups in an alkanediyl group having 2 to 6 carbon atoms being replaced by -O-, -S-, -CO-, -COO-, -NR 22 -, -CO-NR 22 -, -NR 22 -CO-O-, -NR 22 -CO-NR 23 -, -CO-NR 22 -NR 23 -, a divalent group replaced by -SO2-O- or -SO2-. R 22 and R[[ID=?]] 23 are, independently of each other, a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a tert-butoxycarbonyl group. Ar 3 and Ar 4 are, independently of each other, a single bond or a divalent aromatic ring group.)

[0044] As further specific examples of the specific diamine, compounds represented by each of the following formulas (d-1) to formula (d-23) etc. may be mentioned.

Chemical formula

Chemical formula

Chemical formula

[0045] It should be noted that there seems to be an issue with the "[[ID=?]]" in the original text which might be a formatting error. This has been left as is in the translation to maintain consistency with the original.In the synthesis of polyamic acid (P), diamines without a substructure (X) (hereinafter also referred to as "other diamines") may be used alone or in combination with a specific diamine. Known diamines can be used as other diamines, such as aliphatic diamines, aromatic diamines, and diaminoorganosiloxanes. Aliphatic diamines include linear diamines and alicyclic diamines.

[0046] Other specific examples of diamines include, as chain-like diamines, for example, m-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, and 1,3-bis(aminomethyl)cyclohexane; and as alicyclic diamines, for example, 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine); Aromatic diamines include, for example, dodecanoxydiaminobenzene, tetradecanoxydiaminobenzene, pentadecanoxydiaminobenzene, hexadecanoxydiaminobenzene, octadecanoxydiaminobenzene, cholestanyloxydiaminobenzene, cholestanyl diaminobenzoate, cholesteryl diaminobenzoate, lanostanyl diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 1 ,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenoxy)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-(4-heptylcyclohexyl)cyclohexane, N-(2,4-diaminophenyl)-4-(4-heptylcyclohexyl)benzamide, formula (E-1) [ka] (In formula (E-1), X I and X IIThese are, independently, a single bond, -O-, *-COO-, or *-OCO- (where "*" represents a bond with the diaminophenyl group). I This is an alkanediyl group with 1 to 3 carbon atoms. II R is a single bond or an alkanediyl group having 1 to 3 carbon atoms. III (where a is an alkyl group, alkoxy group, fluoroalkyl group, or fluoroalkoxy group having 1 to 20 carbon atoms. a is 0 or 1. b is an integer from 0 to 3. c is an integer from 0 to 2. d is 0 or 1. However, 1 ≤ a + b + c ≤ 3.) Diamines containing directing groups, such as compounds represented by: Paraphenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl sulfide, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 1,2-bis(4-aminophenoxy)ethane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 1,7-bis( 4-aminophenoxy)heptane, bis[2-(4-aminophenyl)ethyl]hexanediic acid, N,N-bis(4-aminophenyl)methylamine, N,N'-di(5-amino-2-pyridyl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine, 4,4'-(2,2'-oxybis(ethane-2,1-diyl)bis(oxy))dianiline, 1,5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diamine Noviphenyl, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(p-phenylenediisopropylidene)bisaniline, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,6-diaminopyridine, 2,4-diaminopyrimidine , 3,6-diaminoacridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, 1,4-bis-(4-aminophenyl)-piperazine, 3,5-diaminobenzoic acid, 1-(4-aminophenoxy)-2-(4-(4'-aminophenyl)phenoxy)ethane, 3,5-diamino-N,N-bis(pyridine-3-ylmethyl)benzamide, etc. Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and diamines described in Japanese Patent Publication No. 2010-97188 can also be used. Other diamines used in the synthesis of polyamic acid (A) can be used individually or in appropriate selections of two or more.

[0047] In the above equation (E-1), "-X I -(R I -X II ) d The divalent group represented by "-" is preferably an alkanediyl group having 1 to 3 carbon atoms, *-O-, *-COO-, or *-O-C2H4-O- (where the bond with "*" is bonded to a diaminophenyl group). III The group represented by is preferably linear. The two amino groups in the diaminophenyl group are preferably located at the 2,4- or 3,5-positions relative to the other group.

[0048] Specific examples of compounds represented by the above formula (E-1) include, for example, the compounds represented by the following formulas (E-1-1) to (E-1-4). [ka]

[0049] When using a specific diamine in the synthesis of polyamic acid (P), the proportion of the specific diamine used is preferably 5 mol% or more, more preferably 20 mol% or more, and even more preferably 40 mol% or more, relative to the total amount of diamine compounds used in the synthesis of polyamic acid (P). When the proportion of the specific diamine used is within the above range, it is possible to obtain a liquid crystal cell that exhibits high transmittance, low pretilt angle characteristics, and good liquid crystal alignment, while also sufficiently obtaining the effect of weak anchoring force on liquid crystal molecules at the interface between the liquid crystal alignment film and the liquid crystal layer. Furthermore, when using a specific diamine in the synthesis of polyamic acid (P), the proportion of the specific diamine used may be 100 mol% or less, relative to the total amount of diamine compounds used in the synthesis of polyamic acid (P). When other diamines are used to impart desired properties, the proportion of the specific diamine used may be, for example, 95 mol% or less, and may also be 90 mol% or less, relative to the total amount of diamine compounds used in the synthesis of polyamic acid (P).

[0050] • Synthesis of polyamic acids Polyamic acid (P) can be obtained by reacting a tetracarboxylic dianhydride and a diamine compound as described above, along with a molecular weight adjusting agent as needed. The ratio of tetracarboxylic dianhydride and diamine compound used in the synthesis reaction of polyamic acid (P) is preferably such that the acid anhydride groups of the tetracarboxylic dianhydride are in the proportion of 0.2 to 2 equivalents, and more preferably 0.3 to 1.2 equivalents, per 1 equivalent of amino groups of the diamine compound.

[0051] Examples of molecular weight modifiers include acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The proportion of molecular weight modifier used is preferably 20 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the total amount of tetracarboxylic dianhydride and diamine compound used.

[0052] The synthesis reaction of polyamic acid (P) is preferably carried out in an organic solvent. The reaction temperature is preferably -20°C to 150°C, and more preferably 0 to 100°C. The reaction time is preferably 0.1 to 24 hours, and more preferably 0.5 to 12 hours.

[0053] Examples of organic solvents used in the reaction include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Of these organic solvents, it is preferable to use one or more selected from the group consisting of aprotic polar solvents and phenolic solvents (organic solvents of group 1), or a mixture of one or more selected from the organic solvents of group 1 and one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons (organic solvents of group 2). In the latter case, the proportion of organic solvents of group 2 used is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, relative to the total amount of organic solvents of group 1 and group 2.

[0054] Particularly preferred organic solvents are one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenol, or a mixture of one or more of these and other organic solvents within the above proportion range. The amount of organic solvent used (x) is preferably such that the total amount of tetracarboxylic dianhydride and diamine compound (y) is 0.1 to 50% by mass of the total amount of the reaction solution (x+y).

[0055] As described above, a reaction solution is obtained by dissolving polyamic acid (P). This reaction solution may be used as is for the preparation of the liquid crystal alignment agent, or the polyamic acid (P) contained in the reaction solution may be isolated and then used for the preparation of the liquid crystal alignment agent, or the isolated polyamic acid (P) may be purified and then used for the preparation of the liquid crystal alignment agent. When dehydrating and cyclizing the polyamic acid (P) to obtain polyimide, the above reaction solution may be used as is for the dehydration and cyclization reaction, or the polyamic acid (P) contained in the reaction solution may be isolated and then used for the dehydration and cyclization reaction, or the isolated polyamic acid (P) may be purified and then used for the dehydration and cyclization reaction. The isolation and purification of polyamic acid (P) can be carried out according to known methods.

[0056] (Polyamic acid ester) Polyamic acid esters as polymers (P) can be obtained, for example, by [I] reacting the polyamic acid (P) obtained by the above synthesis reaction with an esterifying agent, [II] reacting a tetracarboxylic acid diester with a diamine compound, [III] reacting a tetracarboxylic acid dihalide with a diamine compound, etc.

[0057] In this specification, "tetracarboxylic acid diester" means a compound in which two of the four carboxyl groups of tetracarboxylic acid are esterified and the remaining two are carboxyl groups. "Tetracarboxylic acid diester dihalide" means a compound in which two of the four carboxyl groups of tetracarboxylic acid are esterified and the remaining two are halogenated.

[0058] Examples of esterifying agents used in Method [I] include hydroxyl group-containing compounds, acetal compounds, halides, and epoxy group-containing compounds. Specific examples include, as hydroxyl group-containing compounds, alcohols such as methanol, ethanol, and propanol, and phenols such as phenol and cresol; as acetal compounds, N,N-dimethylformamide diethyl acetal and N,N-diethylformamide diethyl acetal; as halides, methyl bromide, ethyl bromide, stearyl bromide, methyl chloride, stearyl chloride, and 1,1,1-trifluoro-2-iodoethane; and as epoxy group-containing compounds, propylene oxide.

[0059] The tetracarboxylic acid diester used in Method [II] can be obtained, for example, by opening the ring of a tetracarboxylic acid dianhydride, as exemplified in the description of the synthesis of polyamic acid (A), using an alcohol such as methanol or ethanol. Note that the tetracarboxylic acid derivative used in Method [II] may be a tetracarboxylic acid diester alone, or a tetracarboxylic acid dianhydride may be used in combination. For the diamine compound, the specific diamine exemplified in the description of the synthesis of polyamic acid (P) may be used alone, or other diamines may be used in combination. When using a specific acid dianhydride in the synthesis, other diamines may be used alone.

[0060] The reaction in method [III] is preferably carried out in an organic solvent in the presence of a suitable dehydration catalyst. Examples of organic solvents include those exemplified for use in the synthesis of polyamic acid (P). Examples of dehydration catalysts include 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholinium halide, carbonylimidazole, and phosphorus-based condensing agents. The reaction temperature is preferably -20 to 150°C, and more preferably 0 to 100°C. The reaction time is preferably 0.1 to 24 hours, and more preferably 0.5 to 12 hours.

[0061] The tetracarboxylic acid diester dihalides used in Method [III] can be obtained, for example, by reacting the tetracarboxylic acid diester obtained as described above with a suitable chlorinating agent such as thionyl chloride. The tetracarboxylic acid derivative used in Method [III] may be solely a tetracarboxylic acid diester dihalide, or a tetracarboxylic acid dianhydride may be used in combination. Furthermore, the diamine compound may be the specific diamine exemplified in the description of the synthesis of polyamic acid (P) used alone, or other diamines may be used in combination. When using a specific acid dianhydride in the synthesis, other diamines may be used alone.

[0062] The reaction in method [III] is preferably carried out in an organic solvent in the presence of a suitable base. Examples of organic solvents include those exemplified for use in the synthesis of polyamic acid (P). Suitable bases include tertiary amines such as pyridine and triethylamine; and alkali metals such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium, and potassium. The reaction temperature is preferably -20 to 150°C, and more preferably 0 to 100°C. The reaction time is preferably 0.1 to 24 hours, and more preferably 0.5 to 12 hours.

[0063] The polyamic acid ester contained in the liquid crystal alignment agent may have only an amic acid ester structure, or it may be a partially esterified product in which both an amic acid structure and an amic acid ester structure coexist. The reaction solution obtained by dissolving the polyamic acid ester may be used directly in the preparation of the liquid crystal alignment agent, or the polyamic acid ester contained in the reaction solution may be isolated and then used in the preparation of the liquid crystal alignment agent, or the isolated polyamic acid ester may be purified and then used in the preparation of the liquid crystal alignment agent. The isolation and purification of the polyamic acid ester can be carried out according to known methods.

[0064] (Polyimide) Polyimide as the polymer (P) can be obtained, for example, by dehydrating and cyclizing the polyamic acid (A) synthesized as described above to perform imidization.

[0065] Polyimides may be fully imidides obtained by dehydrating and cyclizing all of the amic acid structures present in their precursor, polyamic acid, or they may be partially imidides obtained by dehydrating and cyclizing only a portion of the amic acid structure, resulting in the coexistence of amic acid and imide ring structures. The polyimide used in the reaction preferably has an imidation rate of 20% or more, and more preferably 30-99%. This imidation rate is expressed as a percentage of the ratio of the number of imide ring structures to the total number of amic acid structures and imide ring structures in the polyimide. Here, a portion of the imide ring may be an isoimide ring.

[0066] Dehydration and ring closure of polyamic acid is preferably carried out by heating the polyamic acid, or by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration and ring closure catalyst to the solution, and heating as necessary.

[0067] In a method of adding a dehydrating agent and a dehydration ring-closing catalyst to a solution of polyamic acid, the dehydrating agent can be an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride. The amount of dehydrating agent used is preferably 0.01 to 20 moles per mole of the amic acid structure of the polyamic acid. As the dehydration ring-closing catalyst, a tertiary amine such as pyridine, colidine, lutidine, triethylamine, or 1-methylpiperidine can be used. The amount of dehydration ring-closing catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. Examples of organic solvents used in the dehydration ring-closing reaction include those exemplified as those used in the synthesis of polyamic acid. The reaction temperature for the dehydration ring-closing reaction is preferably 0 to 180°C, more preferably 10 to 150°C. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

[0068] In this way, a reaction solution containing polyimide is obtained. This reaction solution may be used as is for the preparation of the liquid crystal alignment agent, or the dehydrating agent and dehydration ring-closing catalyst may be removed from the reaction solution before preparing the liquid crystal alignment agent, or the polyimide may be isolated before preparing the liquid crystal alignment agent, or the isolated polyimide may be purified before preparing the liquid crystal alignment agent. These purification operations can be carried out according to known methods. In addition, polyimide can also be obtained by imidization of polyamic acid esters.

[0069] The polymers (P) obtained as described above, namely polyamic acid, polyamic acid ester, and polyimide, preferably have a solution viscosity of 20 to 1,800 mPa·s when prepared as a 15% by mass solution, and more preferably have a solution viscosity of 50 to 1,500 mPa·s. The solution viscosity (mPa·s) of the polymer is measured at 25°C using an E-type rotational viscometer for a 15% by mass polymer solution prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0070] The weight-average molecular weight (Mw) of polyamic acid, polyamic acid ester, and polyimide as polymers (P), measured by gel permeation chromatography (GPC), is preferably 1,000 to 500,000, and more preferably 2,000 to 300,000. Furthermore, for polyamic acid, polyamic acid ester, and polyimide as polymers (P), the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) measured by GPC, is preferably 8 or less, and more preferably 7 or less. By ensuring that the Mw and Mw / Mn of polyamic acid, polyamic acid ester, and polyimide as polymers (P) are within the above ranges, good liquid crystal alignment of the liquid crystal element can be ensured.

[0071] (addition polymer) The addition polymer (P), as polymer (P), preferably has at least one selected from the group consisting of a substructure represented by the following formula (1-1B) and a substructure represented by the following formula (1-2B). [ka] (In equations (1-1B) and (1-2B), Ar 1 Ar 2 and X 1 This is equivalent to equation (1) above. Y 1 This is either a nitrogen atom, or a trivalent group in which a hydrogen atom, a methyl group, or a hydroxyl group is bonded to a carbon atom. 4 This refers to a single bond, -CO-, -COO-, -CONH-, a divalent aromatic ring group, or a divalent group formed by a divalent aromatic ring group bonded to -CO-, -COO-, or -CONH-. (* indicates a bond with a carbon atom constituting the main chain of the polymer.)

[0072] In the above equations (1-1B) and (1-2B), Ar 1 Ar 2 and X 1 For specific and preferred examples, see Ar in formula (1) above. 1 Ar 2 and X 1 The respective explanations apply. A 4 For specific and preferred examples of the divalent aromatic ring group represented by the above formula (1), see Ar 1 and Ar 2 Examples of such groups include those similar to those exemplified in the explanation of the divalent aromatic ring group represented by .

[0073] The addition polymer (P) can be obtained, for example, by polymerizing a monomer that has polymerizable unsaturated carbon-carbon bonds and includes a monomer having a substructure represented by formula (1-1B) or formula (1-2B) above (hereinafter also referred to as a "specific unsaturated monomer"). Specific examples of specific unsaturated monomers include compounds represented by formulas (v-1) to (v-7) below. [ka] (In formulas (v-1) to (v-5), R is either a hydrogen atom or a methyl group.)

[0074] In the synthesis of addition polymers (P), monomers without substructures (X) (hereinafter also referred to as "other unsaturated monomers") may be used in combination. Examples of other unsaturated monomers include (meth)acrylic compounds, styrene compounds, conjugated diene compounds, and maleimide compounds.

[0075] Other specific examples of unsaturated monomers include (meth)acrylic compounds such as unsaturated carboxylic acids like (meth)acrylic acid; alkyl (meth)acrylates (e.g., methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.); cycloalkyl (meth)acrylates; benzyl (meth)acrylates; trimethoxysilylpropyl (meth)acrylates; 2-hydroxyethyl (meth)acrylates; glycidyl (meth)acrylates; 3,4-epoxycyclohexylmethyl (meth)acrylates; 3,4-epoxybutyl (meth)acrylates; 4-hydroxybutyl glycidyl ether (meth)acrylates; 3-(meth)acryloyloxypropyltrimethoxysilane; 3-(meth)acryloyloxypropyltriethoxysilane; 6-(meth)acryloyloxyhexyltrimethoxysilane; 3-(meth)acryloyloxypropylmethyldimethoxysilane; and 3-(meth)acryloyloxypropylmethyldiethoxysilane, among other unsaturated carboxylic acid esters.

[0076] Aromatic vinyl compounds include styrene, methylstyrene, divinylbenzene, 4-hydroxymethylstyrene, p-styryltrimethoxysilane, 4-(glycidyloxymethyl)styrene, and vinylbenzoic acid. Conjugated diene compounds include 1,3-butadiene and 2-methyl-1,3-butadiene. Maleimide compounds include N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(4-glycidyloxyphenyl)maleimide, and N-glycidylmaleimide.

[0077] Furthermore, other unsaturated monomers other than those mentioned above may be used, including unsaturated monomers having a structure in which one or more rings from among C4-C30 alkyl groups, C4-C30 halogenated alkyl groups, C4-C30 alkoxy groups, C4-C30 halogenated alkoxy groups, benzene rings, and cyclohexane rings are linked together by single bonds or linking groups, or groups having a steroid skeleton. In the synthesis of the addition polymer (P), one of the other unsaturated monomers may be used alone, or two or more may be used in combination.

[0078] Other unsaturated monomers that can be used include compounds having a functional group that can react with the crosslinking group (crosslinking group F1 described later) of compound (A) to form a covalent bond. In particular, at least one selected from the group consisting of unsaturated monomers having a carboxyl group and unsaturated monomers having an amino group can be used.

[0079] In the synthesis of the addition polymer (P), the proportion of the specific unsaturated monomer used is preferably 10 mol% or more, more preferably 20 mol% or more, even more preferably 30 mol% or more, even more preferably 40 mol% or more, and particularly preferably 50 mol% or more, relative to the total amount of monomers used in the synthesis of the addition polymer (P). When the proportion of the specific unsaturated monomer used is within the above range, it is possible to obtain a liquid crystal cell that exhibits high transmittance, low pretilt angle characteristics, and good liquid crystal alignment, while sufficiently providing weak anchoring force to liquid crystal molecules at the interface between the liquid crystal alignment film and the liquid crystal layer. Furthermore, in the synthesis of the addition polymer (P), the proportion of the specific unsaturated monomer used may be 100 mol% or less, relative to the total amount of monomers used in the synthesis of the addition polymer (P). When desired characteristics are imparted by the use of other unsaturated monomers, the proportion of the specific unsaturated monomer used may be, for example, 95 mol% or less, and may also be 90 mol% or less, relative to the total amount of monomers used in the synthesis of the addition polymer (P).

[0080] The synthesis method for the addition polymer (P) is not particularly limited and can be produced by known polymerization methods such as radical polymerization, anionic polymerization, and cationic polymerization. For example, when producing the addition polymer (P) by radical polymerization, the addition polymer (P) can be obtained by polymerizing monomers in the presence of a radical polymerization initiator.

[0081] When producing an addition polymer (P) by radical polymerization, any known compound commonly used in radical polymerization can be used as the radical polymerization initiator. Examples of radical polymerization initiators include azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile). The amount of polymerization initiator used is preferably 0.01 to 30 parts by mass per 100 parts by mass of the total monomer used in the reaction.

[0082] The polymerization reaction is preferably carried out in an organic solvent. Examples of organic solvents used in the reaction include alcohols, ethers, ketones, amides, esters, and hydrocarbon compounds, with diethylene glycol ethyl methyl ether and propylene glycol monomethyl ether acetate being preferred. The reaction temperature is preferably 30°C to 120°C, and the reaction time is preferably 1 to 36 hours. The amount of organic solvent used is preferably such that the total amount of monomers used in the reaction is 0.1 to 60% by mass of the total amount of the reaction solution. The addition polymer (P) can also be obtained by synthesizing an addition polymer having epoxy groups in its side chains, and then reacting the obtained epoxy group-containing addition polymer with a carboxylic acid having a substructure (X).

[0083] For the addition polymer (P), the weight-average molecular weight (Mw) in polystyrene terms, as measured by GPC, is preferably 250 to 500,000, and more preferably 500 to 100,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) in polystyrene terms, as measured by GPC, is preferably 8 or less, and more preferably 6 or less.

[0084] (Polyether) The polyether (hereinafter also referred to as "polyether(P)") as the polymer (P) preferably has a substructure (X) represented by the following formula (1-1C). [ka] (In formula (1-1C), A 5 and A 6 These are either independently divalent aromatic ring groups, or A 5 and A 6 Each of these has an aromatic ring, and these aromatic rings are bonded by a single bond, an oxygen atom, a sulfur atom, and -NR 1 - Or it represents a fused ring structure formed by linking each other with alkanediyl groups having 1 to 3 carbon atoms. Ar 1 Ar 2 , R 1 and X 1This is equivalent to equation (1) above. "*" represents a bond.

[0085] In the above equation (1-1C), Ar 1 Ar 2 and X 1 For specific and preferred examples, see Ar in formula (1) above. 1 Ar 2 and X 1 The respective explanations apply. A 5 Or A 6 For specific and preferred examples of the divalent aromatic ring group represented by the above formula (1), see Ar 1 and Ar 2 Examples of such groups include those similar to those exemplified in the explanation of the divalent aromatic ring group represented by .

[0086] Polyethers (P) can be obtained by reacting a diol compound with a dihalide. In the production of polyethers (P), at least one selected from the group consisting of a diol compound having the substructure represented by formula (1-1C) and a dihalide having the substructure represented by formula (1-1C) can preferably be used as the monomer. Of these, from the viewpoint of the availability of monomers and the ease of synthesis of polymers, it is preferable to use a diol compound having the substructure represented by formula (1-1C) (hereinafter also referred to as "specific diol"). Examples of specific diols include compounds obtained by replacing the two primary amino groups in the compound represented by formula (D1) and the compound represented by formula (D2) with hydroxyl groups.

[0087] Further specific examples of specific diols include compounds represented by the following formulas (OH-1) to (OH-22). [ka] [ka] [ka]

[0088] In the synthesis of polyether (P), diol compounds that do not have a substructure (X) (hereinafter also referred to as "other diols") may be used in combination. Examples of other diols include aliphatic diols (including linear diols and alicyclic diols), and diol compounds in which two hydroxyl groups are bonded to the same or different aromatic rings (hereinafter referred to as "aromatic diols"). From the viewpoint of obtaining an organic film that has excellent heat resistance and rubbing resistance and exhibits good liquid crystal alignment, it is preferable to design the polyether (P) to have a high glass transition temperature of the reaction product, and aromatic diols can be preferably used. Specific examples of aromatic diols include, for example, dihydroxyarenes such as hydroquinone, resorcinol, 4,4'-biphenol, and 3,3'-biphenol; and bisphenols such as biphenol, bisphenol A, 2,2-bis(2-amino-4-hydroxyphenyl)propane, 4,4-bis(4-hydroxyphenyl)valeric acid, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 2,2-bis(4-hydroxyphenyl)1,1,1,3,3,3-hexafluoropropane.

[0089] Furthermore, other diols that have a functional group capable of reacting with the crosslinking group (crosslinking group F1 described later) of compound (A) to form a covalent bond can be preferably used. Among these, diol compounds having a carboxyl group can be preferably used.

[0090] In the synthesis of polyether (P), the proportion of a specific diol used is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 20 mol% or more, and even more preferably 30 mol% or more, relative to the total amount of diol compounds used in the synthesis of polyether (P). By setting the proportion of the specific diol used within the above range, the transmittance of the liquid crystal cell can be increased, and while improving the low pretilt angle characteristics and liquid crystal alignment, the weak anchoring force of liquid crystal molecules at the interface between the liquid crystal alignment film and the liquid crystal layer can be sufficiently achieved. Furthermore, in the synthesis of polyether (P), the proportion of the specific diol used may be 100 mol% or less relative to the total amount of diol compounds used in the synthesis of polyether (P). When other diols are used to impart desired properties, the proportion of the specific diol used may be, for example, 95 mol% or less, and may also be 90 mol% or less, relative to the total amount of diol compounds used in the synthesis of polyether (P).

[0091] In the synthesis of polyethers (P), from the viewpoint of obtaining an organic film with excellent heat resistance and rubbing resistance, and exhibiting good liquid crystal alignment, it is preferable to design the reaction product to have a high glass transition temperature, and a dihalogen compound in which two halo groups are bonded to the same or different aromatic rings (hereinafter referred to as "aromatic dihalides") can be preferably used as the dihalide. Specific examples of aromatic dihalides include 2,6-difluorobenzonitrile, 2,5-difluorobenzonitrile, 2,4-difluorobenzonitrile, 2,6-dichlorobenzonitrile, 4,4'-difluorobenzophenone, 4,4'-difluorodiphenylsulfone, 2,4'-difluorobenzophenone, 2,4'-difluorodiphenylsulfone, 2,2'-difluorobenzophenone, 3,3'-dinitro-4,4'-difluorobenzophenone, and 4,4'-dichlorobenzophenone. Furthermore, as other dihalogen compounds, compounds having a functional group that can react with the crosslinking group (crosslinking group F1 described later) of compound (A) to form a covalent bond can be preferably used.

[0092] Polyethers (P) can be obtained by reacting a diol compound with a dihalide in an organic solvent, preferably in the presence of a base. The ratio of the diol compound to the dihalide used in the synthesis reaction is preferably such that the halogen atoms of the dihalide are 0.2 to 2 equivalents, and more preferably 0.8 to 1.2 equivalents, per 1 equivalent of hydroxyl groups of the diol compound.

[0093] Suitable organic solvents include, for example, tetrahydrofuran, dioxane, toluene, methylene chloride, chloroform, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone. The amount of organic solvent used is preferably 400 to 900 parts by mass, and more preferably 500 to 700 parts by mass, per 100 parts by mass of the total amount of monomers.

[0094] Preferably, the following bases can be used: tertiary amines such as pyridine, triethylamine, tripropylamine, triisopropylamine, N-ethyl-N,N-diisopropylamine, and diazabicycloundecene; and alkali metals such as lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium hydride, sodium hydride, potassium hydride, lithium bis(trimethylsilyl)amide, sodium bis(trimethylsilyl)amide, potassium bis(trimethylsilyl)amide, lithium diisopropylamide, sodium diisopropylamide, potassium diisopropylamide, t-butyllithium, sodium carbonate, and potassium carbonate. Preferably, the amount of base used is 2 to 4 moles, and more preferably 2 to 3 moles, per mole of diol compound.

[0095] In the above reaction, the reaction temperature is preferably -20°C to 150°C, and the reaction time is preferably 0.1 to 24 hours. The reaction solution obtained by dissolving polyether (P) may be used to prepare the liquid crystal alignment agent after isolating the polyether (P) contained in the reaction solution using known isolation methods such as pouring the reaction solution into a large amount of poor solvent and drying the precipitate obtained under reduced pressure, or distilling the reaction solution under reduced pressure using an evaporator.

[0096] The weight-average molecular weight (Mw) of the polyether (P) measured by GPC in terms of polystyrene is preferably 1,000 to 300,000, and more preferably 2,000 to 100,000. In the polyether (P), the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) measured by GPC in terms of polystyrene, is preferably 5 or less, and more preferably 4 or less. The polyether (P) used in the preparation of the liquid crystal alignment agent may be a single type or a combination of two or more types.

[0097] (polyester) The polyester polymer (P), hereinafter also referred to as "polyester (P)", preferably has a substructure represented by the above formula (1-1C) as a substructure (X). Such polyester (P) can be obtained by reacting a diol compound with a dicarboxylic acid. In the production of polyester (P), at least one selected from the group consisting of a diol compound having the above formula (1-1C) and a dicarboxylic acid halide having the above formula (1-1C) can preferably be used as the monomer. Of these, from the viewpoint of the availability of monomers and the ease of synthesis of polymers, it is preferable to use a diol compound having the above formula (1-1C) (i.e., a specific diol). Specific examples of specific diols include the compounds represented by the above formulas (oh-1) to (oh-15).

[0098] Dicarboxylic acids are not particularly limited, but examples include linear dicarboxylic acids such as oxalic acid, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, 3,3-diethylsuccinic acid, fumaric acid, and muconic acid; alicyclic dicarboxylic acids such as cyclobutanedicarboxylic acid, 1-cyclobutenedicarboxylic acid, cyclopentanedicarboxylic acid, and cyclohexanedicarboxylic acid; phthalic acid, isophthalic acid, terephthalic acid, 5-methylisophthalic acid, 4,4'-biphenyldicarboxylic acid, and 4,4'-diphenyl Examples of dicarboxylic acids having aromatic rings include methanedicarboxylic acid, 4,4'-diphenylpropanedicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4-carboxycinnamic acid, p-phenylenediacrylic acid, 3,3'-[4,4'-(methylenedi-p-phenylene)]dipropionic acid, 4,4'-[4,4'-(oxydi-p-phenylene)]dibutyric acid, 3,4-diphenyl-1,2-cyclobutanedicarboxylic acid, and azobenzene-4,4'-dicarboxylic acid. When synthesizing polyester (P), one type of dicarboxylic acid can be used alone or two or more types can be used in combination. It is preferable to acid chloride the dicarboxylic acid using a suitable chlorinating agent such as thionyl chloride, and then react it with a diol compound.

[0099] The reaction between the diol compound and the dicarboxylic acid dihalide is preferably carried out in an organic solvent in the presence of a base. The preferred ratio of the dicarboxylic acid dihalide to the diol compound in the above reaction is 0.2 to 2 equivalents of the "-COX" group (where X is a halogen atom) of the dicarboxylic acid dihalide for every 1 equivalent of the hydroxyl group of the diol compound. The reaction temperature is preferably 0°C to 200°C, and the reaction time is preferably 0.5 to 48 hours. The organic solvent and base used in the reaction are the same as those used in the synthesis of polyether (P). The reaction solution obtained by dissolving polyester (P) may be used directly in the preparation of the liquid crystal alignment agent, or the polyester (P) contained in the reaction solution may be isolated before being used in the preparation of the liquid crystal alignment agent.

[0100] The solution viscosity of polyester (P) is preferably 5 to 800 mPa·s, and more preferably 10 to 500 mPa·s, when it is a 10% by mass solution. The solution viscosity (mPa·s) of polyester (P) is the value measured at 25°C using an E-type rotational viscometer for a 10% by mass polymer solution prepared using a good solvent for polyester (P) (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). The weight-average molecular weight (Mw) of polyester (P) in polystyrene equivalent, measured by GPC, is preferably 1,000 to 500,000, and more preferably 2,000 to 300,000.

[0101] The polymer (P) content in the liquid crystal alignment agent of this disclosure is preferably 15 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, per 100 parts by mass of the solid content (components other than the solvent of the liquid crystal alignment agent) contained in the liquid crystal alignment agent. Furthermore, the polymer (P) content is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 50 parts by mass or more, based on 100 parts by mass of the total polymer components contained in the liquid crystal alignment agent. Note that one type of polymer (P) may be used alone, or two or more types may be used in combination.

[0102] <Compound (A)> Compound (A) is a compound having a total of two or more crosslinkable groups (hereinafter also referred to as "crosslinkable group F1") selected from the group consisting of oxyranyl groups, oxetanyl groups, cyclic carbonate groups, hydroxyl groups, protected hydroxyl groups, mercapto groups, protected mercapto groups, amino groups, protected amino groups, protected isocyanate groups, and polymerizable carbon-carbon unsaturated bond groups, and does not have an aromatic ring. Compound (A) is effective in increasing the mechanical strength of the liquid crystal alignment film by reacting with the functional groups of polymer (P) or by reacting with other compounds (A). This makes it possible to form an organic film with high rubbing resistance. Furthermore, a liquid crystal alignment film obtained using the liquid crystal alignment film of this disclosure can be obtained that exhibits good low pretilt angle characteristics and high transmittance.

[0103] Regarding the crosslinkable group F1, the protected hydroxyl group and the protected Mercart group have a leaving group that bonds to an oxygen atom or a sulfur atom. Preferably, the leaving group is a monovalent group (i.e., a thermally leaving group) that is removed by heat and replaced by a hydrogen atom. From the viewpoint of improving the storage stability and coatability of the liquid crystal alignment agent, it is preferable that the thermally leaving group that bonds to an oxygen atom or a sulfur atom does not leave at room temperature (25°C). More specifically, it is preferable that the thermally leaving group does not leave at 80°C or below, more preferably that it does not leave at 110°C or below, and even more preferably that it does not leave at 130°C or below.

[0104] Examples of leaving groups that bond to an oxygen or sulfur atom include ether-based leaving groups such as methyl, ethyl, tert-butyl, benzyl, p-methoxybenzyl, and trityl groups; acetal-based leaving groups such as methoxymethyl, ethoxyethyl, and 2-tetrahydropyranyl groups; acyl-based leaving groups such as acetyl, pivaloyl, and trichloroacetyl groups; allyl-based leaving groups such as allyl and methallyl groups; carbamate-based leaving groups such as tert-butoxycarbonyl groups; and silyl ether-based leaving groups such as trimethylsilyl, triethylsilyl, and tert-butyldimethylsilyl groups. From the viewpoint of achieving both ease of thermal detachment and storage stability, the leaving group bonded to the oxygen or sulfur atom is preferably an ether-based leaving group, an acetal-based leaving group, a carbamate-based leaving group, or an acetyl group. More preferably, a C4-C7 alkyl group, a 2-tetrahydropyranyl group, a methoxymethyl group, a 1-ethoxyethyl group, a tert-butoxycarbonyl group, or an acetyl group (hereinafter sometimes abbreviated as "Ac") is preferred, and even more preferably, a 2-tetrahydropyranyl group, a methoxymethyl group, a 1-ethoxyethyl group, or an acetyl group is preferred.

[0105] The hydroxyl group and the protected hydroxyl group are preferably bonded to the alkyl chain. Among the hydroxyl groups and protected hydroxyl groups as crosslinkable group F1, it is preferable that they are introduced into compound (A) as hydroxyl groups constituting a hydroxyalkylamide group or a protected hydroxyalkylamide group, due to their high reactivity.

[0106] Examples of amino groups as the crosslinkable group F1 include primary amino groups (-NH2), secondary amino groups (-NH-), and -NH2 in -CO-NH-NH2. The amino group may be bonded to a chain structure or may constitute part of a ring. The protected amino group is preferably a group in which one or two hydrogen atoms in the above-mentioned amino group are replaced by a leaving group.

[0107] The protected amino group preferably has a thermally leaving group as the leaving group bonded to the nitrogen atom. Similarly, it is preferable that this leaving group does not leave at room temperature, more preferably at 80°C or below, and even more preferably at 130°C or below. Specific examples of thermally leaving groups bonded to the nitrogen atom include carbamate leaving groups, amide leaving groups, imide leaving groups, and sulfonamide leaving groups. Of these, carbamate leaving groups are preferred due to their high thermal leaving properties, and specific examples include tert-butoxycarbonyl group, 1,1-dimethyl-2-haloethyloxycarbonyl group, 1,1-dimethyl-2-cyanoethyloxycarbonyl group, and 2-(trimethylsilyl)ethoxycarbonyl group. Of these, the tert-butoxycarbonyl group (Boc group) is particularly preferred because it exhibits excellent thermal leaving properties and can reduce the amount of compound remaining in the film derived from the deprotected structure.

[0108] The protected isocyanate group is preferably protected by a thermally leaving group. Known reagents (blocking agents) can be used to obtain the protected isocyanate group. Specific examples of blocking agents include alcohols, phenols, active methylene compounds, mercaptans, acid amides, acid imides, imidazoles, pyrazoles, ureas, oximes, amines, imines, and pyridines. From the viewpoint of suppressing the retention of components derived from groups detached by heating during film formation in the film, the number of carbon atoms in the thermally leaving group is preferably 1 to 10, and more preferably 1 to 6.

[0109] Examples of polymerizable carbon-carbon unsaturated bonding groups include vinyl groups, vinyloxy groups, allyl groups, (meth)acryloyl groups, maleimide groups, and 3-methylenetetrahydrofuran-2(3H)-on-5-yl groups. Of these, the (meth)acryloyl group is preferred as the polymerizable carbon-carbon unsaturated bonding group F1 due to its high reactivity.

[0110] From the viewpoint of forming a liquid crystal alignment film with excellent rubbing resistance and low pretilt angle characteristics, the number of crosslinkable groups F1 in compound (A) is preferably 3 or more, and more preferably 4 or more. Furthermore, from the viewpoint of suppressing a decrease in the liquid crystal alignment and transmittance of the liquid crystal element, the number of crosslinkable groups F1 in compound (A) is preferably 10 or less, and more preferably 8 or less. The molecular weight of compound (A) is preferably 1,000 or less, more preferably 800 or less, and even more preferably 600 or less.

[0111] Compound (A) does not have an aromatic ring within its molecule. That is, compound (A) is either a compound consisting only of a chain structure (i.e., a chain compound), or a cyclic compound having only a non-aromatic ring as its ring structure. A cyclic compound may have both a ring structure and a chain structure.

[0112] A preferred specific example of compound (A) is the compound represented by the following formula (2). [ka] (In formula (2), B 1 R is an oxyranyl group, an oxetanyl group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, a protected isocyanate group, or a polymerizable carbon-carbon unsaturated bond group. 5 This is an m-valence group consisting of a chain structure, an alicyclic structure, an aliphatic heterocyclic structure, or a combination of two or more of these. m is an integer from 2 to 10. Multiple B in the formula 1 They are either identical or different from one another.

[0113] R 5 If the compound has a chain-like structure, the chain-like structure may consist of saturated or unsaturated chain-like hydrocarbon groups with 1 to 30 carbon atoms and an m-valence, and between the carbon-carbon bonds of the chain-like hydrocarbon groups, -O-, -S-, nitrogen atoms, -CO-, -COO-, and -NR atoms. 10 -,-CO-NR 10 -, -NR 10 -CO-O-, -NR 10 -CO-NR11 - or -CO-NR 10 -NR 11 - A base with m-valence containing (however, R 10 and R 11 These are, independently of each other, hydrogen atoms or monovalent organic groups. The same applies hereinafter.)

[0114] R 5 When a hydrocarbon has an alicyclic structure, the alicyclic structure may include a monocyclic saturated alicyclic hydrocarbon having 3 to 20 carbon atoms, a monocyclic unsaturated alicyclic hydrocarbon, or a polycyclic alicyclic hydrocarbon from which any hydrogen atom has been removed. Specific examples of these alicyclic hydrocarbons include monocyclic saturated alicyclic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane; monocyclic unsaturated alicyclic hydrocarbons such as cyclopentene, cyclohexene, cycloheptene, cyclooctene, and cyclodecene; and polycyclic alicyclic hydrocarbons such as bicyclo[2.2.1]heptane (norbornane), bicyclo[2.2.2]octane, and tricyclo[3.3.1.1] 3,7 Decane (adamantane), tetracyclo[6.2.1.1 3,6 .0 2,7 Examples include dodecane, etc. These rings may have substituents. Examples of substituents include alkyl groups, alkoxy groups, halogen atoms, hydroxyl groups, carboxyl groups, acetyl groups, nitro groups, cyano groups, etc.

[0115] R 5 If the aliphatic heterocyclic structure is present, the aliphatic heterocyclic structure may be a monocyclic saturated alicyclic hydrocarbon, a monocyclic unsaturated alicyclic hydrocarbon, or a polycyclic alicyclic hydrocarbon with 3 to 20 carbon atoms, as exemplified by the alicyclic structure, with -O-, -S-, nitrogen atoms, -CO-, -COO-, and -NR between the carbon-carbon bonds. 10 -,-CO-NR 10 -, -NR 10 -CO-O-, -NR 10 -CO-NR 11 -,-CO-NR 10 -NR 11-Or groups containing a siloxane bond. Specific examples include, for example, piperidine structures, piperazine structures, hexamethyleneimine structures, morpholine structures, isocyanuric acid structures, cyclic siloxane structures, and cyclic urea structures. These rings may have substituents (for example, the groups exemplified in the description of alicyclic structures).

[0116] In the above equation (2), B 1 Specific examples and preferred examples of each group include the groups described above as the crosslinkable group F1. m is between 2 and 10, preferably between 2 and 8, and more preferably between 3 and 8.

[0117] Specific examples of compound (A) include compounds having an oxyranyl group or an oxetanyl group, such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, triglycidyl isocyanurate, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N-diglycidyl-cyclohexylamine, and compounds represented by the following formulas (a1-1) or (a1-2); Compounds having a cyclic carbonate group include those represented by formulas (a2-1) to (a2-3) below; Compounds having a hydroxyl group or a protected hydroxyl group include those represented by formulas (a3-1) to (a3-15) below; Compounds having a mercapto group or a protected mercapto group include those represented by formulas (a4-1) to (a4-2) below; Compounds having an amino group or a protected amino group include those represented by formulas (a5-1) to (a5-15) below; Compounds having a protected isocyanate group include those represented by formulas (a6-1) to (a6-5) below; Examples of compounds having polymerizable carbon-carbon unsaturated bond groups include ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and compounds represented by the following formulas (a7-1) to (a7-8). [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] (In equations (a6-1) and (a6-2), R 23 (This is a tert-butoxy group.) [ka] [ka]

[0118] The content of compound (A) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, based on 100 parts by mass of the total amount of polymer components contained in the liquid crystal alignment agent. By setting the content of compound (A) within the above range, the mechanical strength of the liquid crystal alignment film can be sufficiently increased, film abrasion due to rubbing treatment can be suppressed, and the occurrence of bright spots and alignment defects can be suppressed, which is advantageous. Furthermore, from the viewpoint of suppressing a decrease in the mechanical strength of the liquid crystal alignment film due to the addition of an excessive amount of compound (A), the content of compound (A) is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, based on 100 parts by mass of the total amount of polymer components contained in the liquid crystal alignment agent. Note that compound (A) may be used alone or in combination of two or more types.

[0119] <Other ingredients> The liquid crystal alignment agent of this disclosure may further contain components other than polymer (P) and compound (A) (other components) as needed. Examples of other components include polymers different from polymer (P) (hereinafter also referred to as "other polymers"), solvents, etc.

[0120] (Other polymers) Other polymers may be polymers that do not have a substructure (X), and their main skeleton is not particularly limited. Examples of other polymers include polyamic acid, polyimide, polyamic acid ester, polyorganosiloxane, polyester, cellulose derivative, polyacetal, addition polymer, and polyether. Examples of addition polymers include styrene polymers, (meth)acrylic polymers, maleimide polymers, and styrene-maleimide copolymers. Polymer (B) is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyether, polyester, and addition polymer. Known monomers can be used as monomers constituting the other polymers, for example, monomers that do not have a substructure (X) among the monomers mentioned above.

[0121] When other polymers are included in the liquid crystal alignment agent, the content of the other polymers is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, even more preferably 80 parts by mass or less, and even more preferably 60 parts by mass or less, based on 100 parts by mass of the polymer components contained in the liquid crystal alignment agent (i.e., the total amount of polymer (P) and other polymers). Note that one type of other polymer may be used alone, or two or more types may be used in combination.

[0122] (solvent) The liquid crystal alignment agent of this disclosure is prepared as a liquid composition in which a polymer (P) and a compound (A), and optionally added components, are preferably dissolved in a solvent. The solvent is preferably an organic solvent, such as aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc.

[0123] Specific examples of organic solvents used include, for example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, and ethylene glycol-n Examples include butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate, cyclohexanone, diisobutyl ketone, 3-methoxy-1-butanol, etc. These can be used individually or in combination of two or more.

[0124] Other specific examples of components other than polymers and solvents include functional silane compounds (e.g., 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, etc.), antioxidants, metal chelating compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, etc. The content of these components can be appropriately selected depending on each compound, within a range that does not impair the effects of this disclosure.

[0125] The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of components other than the solvent to the total mass of the liquid crystal alignment agent) can be appropriately selected considering viscosity, volatility, etc. The solid content concentration of the liquid crystal alignment agent is preferably in the range of 1 to 10% by mass. When the solid content concentration is 1% by mass or more, it is possible to ensure sufficient film thickness of the coating and tend to yield a good liquid crystal alignment film. On the other hand, when the solid content concentration is 10% by mass or less, the film thickness of the coating does not become excessive, and the viscosity of the liquid crystal alignment agent can be made moderately high, which tends to result in good coatability.

[0126] <Liquid crystal alignment films and liquid crystal elements> The liquid crystal alignment film of this disclosure is formed from a liquid crystal alignment agent prepared as described above. The liquid crystal element of this disclosure has a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The operating mode of the liquid crystal in the liquid crystal element is not particularly limited. Examples of operating modes include TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS (In-Plane Switching) type, FFS (Fringe Field Switching) type, OCB (Optically Compensated Bend) type, and PSA type (Polymer Sustained Alignment). The liquid crystal element can be manufactured by a method including, for example, the following steps 1 to 3. In step 1, the substrate used differs depending on the desired operating mode. Steps 2 and 3 are common to each operating mode.

[0127] <Step 1: Formation of the coating> Step 1 is a step of forming a coating film using the liquid crystal alignment agent of this disclosure. From the viewpoint of manufacturing efficiency and forming a highly uniform film, it is preferable that in Step 1, the liquid crystal alignment agent is applied to the substrate and the coating surface is heated to form a coating film on the substrate. As the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of resin such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or poly(alicyclic olefin) can be used. When manufacturing TN type, STN type, or VA type liquid crystal elements, two substrates on which a patterned transparent conductive film is provided are used. When manufacturing IPS type or FFS type liquid crystal elements, a substrate on which a comb-shaped patterned electrode (comb-shaped electrode) is provided and a counter substrate on which no electrode is provided are used. In the case of the FFS type, a substrate on which a surface electrode is provided along with the comb-shaped electrode is used. As the transparent conductive film, a NESA film (registered trademark of PPG, Inc., USA) made of tin oxide (SnO2), an ITO film made of indium oxide-tin oxide (In2O3-SnO2), etc. can be used. The liquid crystal alignment agent is applied to the substrate surface, preferably by offset printing, flexographic printing, spin coating, roll coating, or inkjet printing.

[0128] In step 1, the liquid crystal alignment agent applied to each substrate in a pair of substrates may have the same composition or different compositions between the substrates. For example, for a pair of substrates consisting of a first substrate and a second substrate, the liquid crystal alignment agent of the present disclosure (i.e., a liquid crystal alignment agent containing a polymer (P) and a compound (A)) may be applied to both the first and second substrates to form a coating film. Alternatively, the liquid crystal alignment agent of the present disclosure may be applied to one of the first and second substrates to form a coating film, and a liquid crystal alignment agent that does not contain polymer (P) may be applied to the other substrate to form a coating film. Of these, by forming a liquid crystal alignment film on each of the pair of substrates using the liquid crystal alignment agent of the present disclosure, a liquid crystal element with a lower driving voltage and higher transmittance can be obtained. Furthermore, by forming a liquid crystal alignment film on one of the pair of substrates using the liquid crystal alignment agent of the present disclosure, and forming a liquid crystal alignment film on the other substrate using a liquid crystal alignment agent that does not contain polymer (P), a liquid crystal element with a faster liquid crystal response speed can be obtained.

[0129] Therefore, in liquid crystal elements where both the response speed of the liquid crystal when a voltage is applied to the liquid crystal element and the response speed of the liquid crystal when switching from a voltage-applied state to a voltage-release state are required to be fast, it is preferable to form the liquid crystal alignment film on one of the pair of substrates using the liquid crystal alignment agent of this disclosure. Furthermore, in liquid crystal elements that display by aligning liquid crystal molecules perpendicular to the substrate (TN type, VA type, etc.), it is preferable to form the liquid crystal alignment film on one of the pair of substrates using the liquid crystal alignment agent of this disclosure in order to stabilize the initial alignment orientation of the liquid crystal. By applying the liquid crystal alignment agent of this disclosure to only one side of the pair of substrates, it is possible to realize a liquid crystal element that has a fast liquid crystal response speed and can be driven at a lower voltage while suppressing the occurrence of abnormal domains, etc.

[0130] After applying the liquid crystal alignment agent, preheating (pre-bake) is preferably performed to prevent dripping of the applied liquid crystal alignment agent. The pre-bake temperature is preferably 30 to 200°C, and the pre-bake time is preferably 0.25 to 10 minutes. Subsequently, a baking (post-bake) process is performed to remove the solvent in the applied liquid crystal alignment agent. The baking temperature (post-bake temperature) at this time is preferably 80 to 250°C, more preferably 80 to 200°C. The post-bake time is preferably 5 to 200 minutes. The thickness of the film formed in this way is preferably 0.001 to 1 μm.

[0131] <Step 2: Orientation Treatment> When manufacturing TN, STN, IPS, or FFS type liquid crystal elements, a process (alignment treatment) is performed to impart liquid crystal alignment ability to the coating film formed in step 1 above. This imparts liquid crystal molecule alignment ability to the coating film, making it a liquid crystal alignment film. As an alignment treatment, methods such as rubbing, in which the coating film formed on the substrate is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton, or photo-alignment, in which light is irradiated onto the coating film formed on the substrate to impart liquid crystal alignment ability to the coating film, can be used. On the other hand, when manufacturing vertical alignment (VA) type liquid crystal elements, the coating film formed in step 1 can be used as is as a liquid crystal alignment film, but an alignment treatment may be applied to the coating film to further enhance its liquid crystal alignment ability. A liquid crystal alignment film suitable for vertical alignment type liquid crystal elements is also suitable for PSA type liquid crystal elements. The organic film formed by the liquid crystal alignment agent of this disclosure has high mechanical strength, and even when rubbing is performed, there is little occurrence of film abrasion. Therefore, in step 2, it is preferable to apply a rubbing treatment to the coating film formed in step 1 to impart liquid crystal alignment ability. In other words, the liquid crystal alignment agent of this disclosure is particularly suitable as a polymer composition for forming a rubbing alignment film.

[0132] <Step 3: Liquid Crystal Cell Construction> In the subsequent step 3, two substrates on which liquid crystal alignment films have been formed as described above are prepared, and a liquid crystal cell is manufactured between the two substrates so that liquid crystal is arranged adjacent to the liquid crystal alignment film. Methods for manufacturing a liquid crystal cell include, for example, placing two substrates opposite each other with a gap in between so that the liquid crystal alignment films face each other, bonding the periphery of the two substrates with a sealant, injecting and filling the cell gap surrounded by the substrate surface and the sealant, and sealing the injection hole, or the ODF method. As the sealant, epoxy resin containing a curing agent and aluminum oxide spheres as spacers can be used. As the liquid crystal, nematic liquid crystal and smectic liquid crystal can be used, with nematic liquid crystal being preferred. In the PSA mode, a liquid crystal cell is constructed by placing a photopolymerizable compound together with liquid crystal between the two substrates, and after the construction of the liquid crystal cell, a voltage is applied between the conductive films of the pair of substrates, and the liquid crystal cell is irradiated with light.

[0133] For liquid crystal cells manufactured as described above, a polarizing plate may be bonded to the outer surface of the liquid crystal cell as needed. Examples of polarizing plates include a polarizing plate in which a polarizing film called an "H film," which is made by stretching and oriented polyvinyl alcohol and absorbing iodine, is sandwiched between cellulose acetate protective films, or a polarizing plate made of the H film itself.

[0134] The liquid crystal elements of this disclosure can be effectively applied to devices for various applications that realize required functions through the properties of liquid crystals. Specifically, they can be applied to various liquid crystal display devices such as liquid crystal televisions, watches, portable game consoles, word processors, personal computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, hologram display devices, various monitors, and information displays, as well as electronic paper, dimmable glass, dimmable films, phase difference films, liquid crystal lenses, liquid crystal antennas, liquid crystal shutters, and the like.

[0135] According to the disclosure described above, the following means are provided. [Method 1] A liquid crystal alignment agent comprising: a polymer (P) having a substructure composed of removing one or more hydrogen atoms from the ring portion of the structure represented by the above formula (1) (except for the fluorene ring in the 9-fluorenylmethyloxycarbonyl group); and a compound (A) having a total of two or more of at least one selected from the group consisting of an oxiranyl group, an oxetanyl group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, a protected isocyanate group, and a polymerizable carbon-carbon unsaturated bond group in one molecule, and having no aromatic ring. [Method 2] The liquid crystal alignment agent according to [Method 1], wherein the polymer (P) has at least one selected from the group consisting of a substructure represented by formula (1-1) and a substructure represented by formula (1-2). [Method 3] The liquid crystal alignment agent according to [Method 1] or [Method 2], wherein the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyether, polyester and addition polymer. [Method 4] The liquid crystal alignment agent according to any one of [Method 1] to [Method 3], wherein the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and has at least one selected from the group consisting of a substructure represented by formula (1-1A) and a substructure represented by formula (1-2A). [Method 5] The liquid crystal alignment agent according to [Method 4], wherein the polymer (P) comprises a structural unit selected from the group consisting of a diamine having a substructure represented by formula (1-1A) and a diamine having a substructure represented by formula (1-2A). [Method 6] The liquid crystal alignment agent according to [Method 4] or [Method 5], wherein the polymer (P) includes structural units derived from a tetracarboxylic dianhydride having a substructure represented by the above formula (1-1A). [Method 7] The liquid crystal alignment agent according to any one of [Method 4] to [Method 6], wherein the polymer (P) contains structural units derived from an alicyclic tetracarboxylic dianhydride. [Method 8] The liquid crystal alignment agent according to [Method 1] or [Method 2], wherein the polymer (P) is an addition polymer and has at least one selected from the group consisting of a substructure represented by formula (1-1B) and a substructure represented by formula (1-2B). [Means 9] The polymer (P) is a polyether and has a substructure represented by the above formula (1-1C), as described in [Method 1] or [Method 2], the liquid crystal alignment agent. [Method 10] The liquid crystal alignment agent according to [Method 1] or [Method 2], wherein the polymer (P) is polyester and has a substructure represented by the above formula (1-1C). [Method 11] A liquid crystal alignment agent according to any one of [Method 1] to [Method 10], wherein the liquid crystal alignment agent contains 30 mol% or more of structural units having a substructure composed of removing one or more hydrogen atoms from the ring portion of the structure represented by formula (1) above, relative to the total structural units constituting the polymer (P). [Method 12] A liquid crystal alignment agent according to any one of [Method 1] to [Method 11], further containing a polymer different from the polymer (P). [Method 13] The compound (A) is a liquid crystal alignment agent represented by formula (2) above, as described in any of [Method 1] to [Method 12]. [Method 14] A method for manufacturing a liquid crystal alignment film, comprising the steps of forming a coating film using a liquid crystal alignment agent described in any of [Method 1] to [Method 13], and subjecting the coating film to a rubbing treatment to impart liquid crystal alignment ability. [Method 15] A liquid crystal alignment film formed with a liquid crystal alignment agent described in any of [Method 1] to [Method 13]. [Method 16] A liquid crystal element comprising the liquid crystal alignment film described in [Method 15]. [Mean 17] A liquid crystal element according to [Mean 16], comprising a pair of substrates, wherein a liquid crystal alignment film is formed on one of the substrates of the pair using a liquid crystal alignment agent described in any of [Mean 1] to [Mean 13], and a liquid crystal alignment film is formed on the other substrate using a liquid crystal alignment agent that does not contain the polymer (P). [Mean 18] A liquid crystal element according to [Mean 16], comprising a pair of substrates, wherein a liquid crystal alignment film is formed on each of the pair of substrates using a liquid crystal alignment agent described in any of [Mean 1] to [Mean 13]. [Examples]

[0136] The present invention will be described in detail below with reference to examples, but it is not limited to the following examples.

[0137] In the following examples, the solution viscosity, weight-average molecular weight (Mw), and number-average molecular weight (Mn) of the polymer, as well as the imidation rate of the polyimide, were measured by the following methods. <Solution viscosity of polymers> The solution viscosity of the polymer was measured at 25°C using an E-type viscometer. <Weight-average molecular weight (Mw) and number-average molecular weight (Mn)> Mw and Mn were measured by gel permeation chromatography (GPC) under the following conditions. The molecular weight distribution (Mw / Mn) was calculated from the obtained Mw and Mn values. Equipment: Showa Denko Corporation's "GPC-101" GPC columns: Combining "GPC-KF-801", "GPC-KF-802", "GPC-KF-803", and "GPC-KF-804" manufactured by Shimadzu GLC Co., Ltd. Mobile phase: Tetrahydrofuran (THF) Column temperature: 40℃ Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Detector: Differential refractometer Standard material: Monodisperse polystyrene <Imidification rate of polyimides> A polyimide solution was added to pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. Then it was dissolved in deuterated dimethyl sulfoxide, with tetramethylsilane as the reference substance, at room temperature. 1 1H-NMR measurements were performed. 1 The imidization rate [%] was determined from the 1H-NMR spectrum using the following formula (1). Imidation rate [%] = (1 - (β 1 / (β 2 ×α))) × 100 …(1) (In formula (1), β 1 is the peak area derived from the proton of the NH group that appears around a chemical shift of 10 ppm, β 2 is the peak area derived from other protons, and α is the ratio of the number of other protons to one proton of the NH group in the precursor (polyamic acid) of the polymer.)

[0138] The abbreviations of the compounds used in the following examples are shown below. For convenience, in the following, "the compound represented by formula (X)" may be simply referred to as "compound (X)". "Boc" in the formula represents a tert-butoxycarbonyl group.)

[0139] <Tetracarboxylic dianhydride>

Chemical formula

Chemical formula

[0140] <Diamine compound>

Chemical formula

Chemical formula

Chemical formula

[0141] <Monomer having a polymerizable unsaturated bond>

Chemical formula

[0142] <Diol compound>

Chemical formula

[0143] <Additive>

Chem.

Chem.

[0144] <Synthesis of Polymer> 1. Synthesis of Polyamic Acid [Synthesis Example 1-1] 100 mol parts of compound (TB-3) as tetracarboxylic dianhydride and 100 mol parts of compound (DA-1) as diamine compound were dissolved in N-methyl-2-pyrrolidone (NMP), and reacted at 60 °C for 6 hours to obtain a solution containing 20% by mass of polyamic acid (this is designated as polymer (PI-1)).

[0145] [Synthesis Examples 1-4 to 1-25] The same operations as in Synthesis Example 1-1 were carried out except that the types and amounts of the tetracarboxylic dianhydride and diamine compound used were changed as shown in Table 1, and polyamic acids (polymers (PI-4) to (PI-25)) were obtained. In Table 1, the numerical values of the tetracarboxylic dianhydride represent the ratio (molar ratio) of each compound to the total amount of 100 mol parts of the tetracarboxylic dianhydride used in the synthesis of the polymer. The numerical values of the diamine compound represent the ratio (molar ratio) of each compound to the total amount of 100 mol parts of the diamine compound used in the synthesis of the polymer.

[0146] 2. Synthesis of Polyimide [Synthesis Example 1-2] 50 moles each of compound (TB-1) and compound (TB-3) as tetracarboxylic dianhydrides, and 80 moles each of compound (DA-2) and compound (DB-2) as diamine compounds were dissolved in NMP and reacted at 60°C for 6 hours to obtain a solution containing 20% ​​by mass of polyamic acid. Next, NMP was added to the obtained polyamic acid solution to make a 10% by mass solution of polyamic acid, and pyridine and acetic anhydride were added to carry out a dehydration and cyclization reaction at 80°C for 4 hours. After the dehydration and cyclization reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by mass of polyimide (referred to as polymer (PI-2)) with an imidization rate of approximately 50%.

[0147] [Synthesis Examples 1-3, 1-26] Polyimides (polymer (PI-3), polymer (PI-26)) were obtained by performing the same procedure as in Synthesis Example 1-2, except that the types and amounts of tetracarboxylic dianhydride and diamine compounds used were changed as shown in Table 1.

[0148] [Table 1]

[0149] 3. Synthesis of addition polymers [Synthesis Example 2-1] Under nitrogen, in a 100 mL two-necked flask, 85 moles of compound (M-1), 7.5 moles of compound (M-5), and 7.5 moles of compound (M-6) were added to a total of 100 moles of polymerization monomers. Additionally, 10 parts by mass of 2,2'-azobis(2,4-dimethylvaleronitrile) was added as a radical polymerization initiator per 100 parts by mass of polymerization monomers, and 400 parts by mass of N-methyl-2-pyrrolidone (NMP) was added as a solvent per 100 parts by mass of polymerization monomers. Polymerization was carried out at 70°C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and vacuum-dried at room temperature for 8 hours to obtain the desired addition polymer (referred to as polymer (PM-1)).

[0150] [Synthesis Examples 2-2 to 2-5] Except for changing the type and amount of polymerization monomer used as shown in Table 2, the same procedure as in Synthesis Example 2-1 was performed to obtain addition polymers (polymers (PM-2) to (PM-5)).

[0151] [Table 2]

[0152] 4. Polyester synthesis [Synthesis Example 3-1] In a 500 mL three-necked flask equipped with a stirrer, 3.0 g of 9,9-bis(hydroxyphenyl)fluorene (compound (E-1)), 0.7 g of sodium hydroxide, 1.0 g of tetrabutylammonium bromide, and 100 mL of water were placed and stirred at room temperature for 30 minutes. 30 mL of a solution of 1,2-dichloroethane containing 1.56 g of adipoyl dichloride was then added and the mixture was vigorously stirred for 15 minutes. The stirring was reduced, 100 mL of heptane was added to precipitate the polymer, and the liquid component was removed by filtration. Next, the obtained solid component was transferred to a beaker, 100 mL of water was added, and after stirring and washing, it was filtered and dried to obtain the target polyester (referred to as polymer (PS-1)) (yield 3.9 g).

[0153] 5. Synthesis of polyethers [Synthesis Example 4-1] In a 3 L four-necked flask, 35.12 g (0.253 mol) of 2,6-difluorobenzonitrile, 87.60 g (0.250 mol) of 9,9-bis(4-hydroxyphenyl)fluorene (Compound (E-1)), 41.46 g (0.300 mol) of potassium carbonate, 443 g of N,N-dimethylacetamide, and 111 g of toluene were added. Subsequently, a thermometer, a stirrer, a three-way cock with a nitrogen inlet tube, a Dean-Stark tube, and a condenser were attached to the four-necked flask. Then, after purging the inside of the flask with nitrogen, the resulting solution was reacted at 140 °C for 3 hours, and the water produced was removed from the Dean-Stark tube as it was generated. When no more water production was observed, the temperature was gradually raised to 160 °C and the reaction was carried out at that temperature for 6 hours. After cooling to room temperature (25 °C), the generated salt was removed with filter paper, the filtrate was poured into methanol for reprecipitation, and the precipitate (residue) was isolated by filtration. The obtained precipitate was vacuum dried at 60 °C overnight to obtain a white powder (designated as polymer (PE-1)) (yield 95.67 g, yield 95%).

[0154] [Synthesis Examples 4-2 to 4-4] The same operations as in Synthesis Example 4-1 were carried out except that the types and amounts of the monomers used were changed as shown in Table 3 to obtain polyethers (polymers (PE-2) to (PE-4)). In Table 3, "F-1" represents 2,6-difluorobenzonitrile. In Table 3, the numerical values of the diol compounds represent the ratio (molar ratio) of each compound to the total amount of 100 mol parts of the diol compounds used in the synthesis of the polymer. The numerical values of the dihalides represent the ratio (molar ratio) of each compound to the total amount of 100 mol parts of the dihalides used in the synthesis of the polymer.

[0155]

Table 3

[0156] [Preparation and Evaluation of Liquid Crystal Alignment Agent] [Example 1] 1. Preparation of Liquid Crystal Alignment Agent To a solution containing 100 parts by mass of polymer (PI-1) obtained in Synthesis Example 1-1, 10 parts by mass of compound (AD-1) were added and diluted with N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) to obtain a solution with a solvent composition of NMP / BC = 70 / 30 (mass ratio) and a solid content concentration of 3.5% by mass. Liquid crystal alignment agent (AL-1) was prepared by filtering this solution through a pore size filter of 0.2 μm.

[0157] 2. Manufacturing of FFS-type liquid crystal cells using the rubbing method A glass substrate (referred to as the first substrate) was prepared, in which a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) were laminated on one side in this order, and a glass substrate (referred to as the second substrate) was prepared without electrodes. Next, a liquid crystal alignment agent (AL-1) was applied to the electrode-forming surface of the first substrate and one side of the second substrate using a spinner, and heated on an 80°C hot plate for 3 minutes (pre-bake). After that, it was dried for 30 minutes in a 230°C oven with nitrogen purging (post-bake) to form a coating with an average film thickness of 0.10 μm. Next, the surface of the coating was rubbed using a rubbing machine with a roll wrapped in rayon cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / second, and a pile insertion length of 0.3 mm. After that, ultrasonic cleaning was performed in ultrapure water for 1 minute, and then drying in a 100°C clean oven for 10 minutes to obtain a pair of substrates having a liquid crystal alignment film. Next, for a pair of substrates having a liquid crystal alignment film, an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was screen-printed onto the edges of the surface where the liquid crystal alignment film was formed. Then, the substrates were stacked and pressed together, and the adhesive was heat-cured at 150°C for 1 hour. Next, positive-type liquid crystal was filled into the gap between the pair of substrates through the liquid crystal injection port, and then the liquid crystal injection port was sealed with epoxy adhesive. Furthermore, to eliminate the flow orientation during liquid crystal injection, this was heated to 120°C and then slowly cooled to room temperature to manufacture a liquid crystal cell. When stacking the pair of substrates, the rubbing directions of each substrate were made antiparallel.

[0158] 3. Evaluation of low pre-tilt angle characteristics For the liquid crystal cells manufactured in step 2 above, the tilt angle of the liquid crystal molecules from the substrate surface was measured by a crystal rotation method using He-Ne laser light, in accordance with the method described in the non-patent document "TJ Scheffer et. al. J. Appl. Phys. vo. 19, p. 2013 (1980)," and this was defined as the pre-tilt angle. A measured pre-tilt angle of less than 0.3 degrees was rated as "good (○)," 0.3 degrees or more and less than 0.5 degrees as "acceptable (△)," and 0.5 degrees or more as "unacceptable (×)." As a result, the evaluation of the low pre-tilt angle characteristics of this example was "good (○)."

[0159] 4. Evaluation of rubbing resistance The liquid crystal alignment agent (AL-1) prepared in step 1 above was applied to a glass substrate using a spinner and heated on an 80°C hot plate for 3 minutes (pre-bake). Then, it was dried in a 230°C oven with nitrogen purging for 30 minutes (post-bake) to form a coating with an average thickness of 0.10 μm, and the haze value of the coating was measured using a haze meter. Next, this coating was subjected to rubbing five times using a rubbing machine with a roll wrapped in cotton cloth, at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / second, and a pile insertion length of 0.3 mm. Afterward, the haze value of the liquid crystal alignment film was measured using a haze meter, and the difference from the haze value before rubbing (haze change value) was calculated using the following formula (3). Haze change value (%) = [Haze value of the film after rubbing treatment (%)] - [Haze value of the film before rubbing treatment (%)] ... (3) The rubbing resistance of the liquid crystal alignment film was evaluated as follows: a haze change value of less than 0.5 was rated as "Excellent (◎)", a haze change value of 0.5 or more and less than 0.8 was rated as "Good (○)", a haze change value of 0.8 or more and less than 1.0 was rated as "Acceptable (△)", and a haze change value of 1.0 or more was rated as "Poor (×)". A haze change value of less than 1.0 (more preferably less than 0.5) indicates sufficiently high film strength and excellent rubbing resistance. As a result, in this example, the rubbing resistance was rated as "Excellent (◎)".

[0160] 5. Evaluation of drive threshold voltage and maximum brightness voltage A white LED backlight and a luminance meter were set up so that the optical axis was aligned. A liquid crystal cell (liquid crystal display element) with a polarizing plate attached to minimize brightness was placed between the white LED backlight and the luminance meter. Voltage was applied in 1V increments up to 6V, and the luminance was measured as a function of the applied voltage to obtain a VT curve. From the obtained VT curve, the drive threshold voltage and the voltage at which brightness is maximum (maximum brightness voltage) were estimated. For the drive threshold voltage, a voltage below 1.3V at which 5% of the maximum brightness is achieved was rated as "Good (○)", a voltage between 1.3V and 1.5V was rated as "Acceptable (△)", and a voltage above 1.5V was rated as "Poor (×)". Similarly, for the maximum brightness voltage, a voltage below 4.5V was rated as "Good (○)", a voltage between 4.5V and 5.0V was rated as "Acceptable (△)", and a voltage above 5.0V was rated as "Poor (×)". As a result, in this embodiment, both the drive threshold voltage and the maximum brightness voltage were judged as "Good (○)".

[0161] 6. Measurement of Cell Transmittance (1) Fabrication of liquid crystal cells In the manufacturing method used in "Manufacturing of FFS-type liquid crystal cells using the rubbing method" described in 2. above, liquid crystal cells were fabricated using the same method except that both the first and second substrates were changed to glass substrates with transparent electrodes made of ITO film. (2) Transmittance measurement The absorption spectrum in the ultraviolet and visible light region was measured for the liquid crystal cell prepared in (1) above using an ultraviolet-visible near-infrared spectrophotometer (manufactured by JASCO Corporation, product name "V-670"). The incident angle on the liquid crystal cell was set to 0°. A transmittance of 89% or higher in the wavelength range of 380 to 800 nm was classified as "good (○)", a transmittance of 88% or higher but less than 89% was classified as "acceptable (△)", and a transmittance of less than 88% was classified as "poor (×)". As a result, the cell transmittance in this example was judged to be "good (○)".

[0162] 7. Evaluation of liquid crystal alignment For the liquid crystal cells manufactured in step 2 above, the presence or absence of abnormal domains was observed using a microscope (magnification 50x) based on the change in brightness when the voltage was turned on and off (applied and released), and the liquid crystal alignment was evaluated. In this case, the absence of abnormal domains was judged as "good (○)", and the presence of abnormal domains was judged as "bad (×)". As a result, in this embodiment, the liquid crystal alignment was judged to be "good (○)".

[0163] 8. Evaluation of LCD response speed Each liquid crystal cell manufactured in step 2 above, "Manufacturing of FFS-type liquid crystal cells using the rubbing method," was sandwiched between two polarizing plates arranged in a crossed nicol configuration and then connected to a function generator. The liquid crystal cells connected to the function generator were placed on a backlight, and first, without applying voltage, the brightness of the light transmitted through the liquid crystal cells was measured using a photomultimeter. This value was defined as a relative transmittance of 0%. Next, when a square wave with an amplitude of ±5V was applied between the electrodes of the liquid crystal cells using the function generator for 5 seconds, the transmittance was measured in the same manner as above, and this value was defined as a relative transmittance of 100%. Furthermore, when a square wave with an amplitude of ±5V was applied to each liquid crystal cell using the function generator, the time it took for the relative transmittance to shift from 10% to 90% was measured, and this time was defined as the response speed of the liquid crystal in the ON state (when voltage is applied). In addition, when the application of the square wave was stopped and the state was switched to 0V application, the time it took for the relative transmittance to shift from 90% to 10% was measured, and this time was defined as the response speed in the OFF state (when voltage application is removed). For both the response speed in the ON state and the response speed in the OFF state, a response speed of less than 20ms was classified as "Good (○)", a response speed of 20ms or more but less than 25ms was classified as "Acceptable (△)", and a response speed of 25ms or more was classified as "Poor (×)". As a result, in this embodiment, both the response speed in the ON state and the response speed in the OFF state were judged to be "Good (○)".

[0164] [Examples 2-29, Comparative Examples 1-6] Except for changing the composition of the liquid crystal alignment agent as shown in Table 4, the liquid crystal alignment agents (AL-2) to (AL-29) and (AR-1) to (AR-6) were prepared with the same solvent composition and solid content concentration as in Example 1. Furthermore, the same evaluation as in Example 1 was performed using each liquid crystal alignment agent. Note that in liquid crystal alignment films containing a polymer with substructure (X), the liquid crystal molecules are oriented in a direction perpendicular to the rubbing direction, while in liquid crystal alignment films without a polymer containing substructure (X), the liquid crystal molecules are oriented along the rubbing direction. Therefore, in Comparative Examples 1 to 3 and 6, which do not use a polymer containing substructure (X), the rubbing direction was changed to a direction perpendicular to the rubbing direction used in 2. "Manufacturing of FFS-type liquid crystal cells using the rubbing method" of Example 1 to produce liquid crystal cells. In Comparative Examples 4 and 5, the rubbing process was performed using the same direction as the rubbing direction in 2. "Manufacturing of FFS-type liquid crystal cells using the rubbing method" of Example 1 to produce liquid crystal cells.

[0165] Table 4 shows the evaluation results for Examples 1-29 and Comparative Examples 1-6. In Table 4, the numbers in parentheses for each component in the orientation agent composition represent the amount (parts by mass) used. In Table 4, the abbreviation "PM-6" in the polymer column represents poly(9-vinylcarbazole) (manufactured by Aldrich, Mw=1,100,000, Tg=200℃). In Comparative Example 5, the polymer (PM-6) was dissolved in a mixed solvent of N-methyl-2-pyrrolidone / ethylene glycol monobutyl ether (volume ratio 1 / 1) and used as a 3% polymer solution. Blank spaces indicate that the compound was not used.

[0166] [Table 4]

[0167] As shown in Table 4, in Examples 1 to 29, which used liquid crystal alignment agents containing polymer (P) and compound (A), the low pre-tilt angle characteristics, rubbing resistance, driving voltage threshold, maximum brightness voltage, cell transmittance, liquid crystal alignment, and liquid crystal response speed evaluation were all "excellent (◎)" or "good (○)," demonstrating a well-balanced improvement in various characteristics. In contrast, in Comparative Examples 1 to 6, which used liquid crystal alignment agents that did not contain either polymer (P) or compound (A) or both, there was one or more "defective (×)" results, indicating inferiority to Examples 1 to 29.

[0168] [Example 30] In Example 1, liquid crystal cells were manufactured using the same method as described in section 2, "Manufacturing of FFS-type liquid crystal cells using the rubbing method," except that a liquid crystal alignment agent (AL-1) was applied to the first substrate using a spinner, and a liquid crystal alignment agent (AR-3) was applied to the second substrate using a spinner to form liquid crystal alignment films. The rubbing direction of the second substrate was set to be perpendicular to the rubbing direction of the second substrate in section 2, "Manufacturing of FFS-type liquid crystal cells using the rubbing method," of Example 1. When stacking the pair of substrates, they were rotated so that the rubbing direction of the second substrate was perpendicular to the rubbing direction of the first substrate, and the liquid crystal cells were manufactured. Using the manufactured liquid crystal cells, the drive threshold voltage, maximum brightness voltage, cell transmittance, liquid crystal alignment, and liquid crystal response speed were evaluated using the same method as in Example 1. The results are shown in Table 6.

[0169] [Examples 31-33] Liquid crystal alignment agents (AR-7) and (AR-8) were prepared with the same solvent composition and solid content concentration as in Example 1, except that the composition of the liquid crystal alignment agent was changed as shown in Table 5. Furthermore, the same procedure as in Example 30 was performed and evaluated, except that the combination of liquid crystal alignment agents to be deposited on the first and second substrates was changed as shown in Table 6. The results are shown in Table 6.

[0170] [Example 34] In Example 1, liquid crystal cells were manufactured using the same method as described in section 2, "Manufacturing of FFS-type liquid crystal cells using the rubbing method," except that a liquid crystal alignment agent (AR-8) was applied to the first substrate using a spinner, and a liquid crystal alignment agent (AL-1) was applied to the second substrate using a spinner to form liquid crystal alignment films. The rubbing direction of the first substrate was set to be perpendicular to the rubbing direction of the first substrate in section 2, "Manufacturing of FFS-type liquid crystal cells using the rubbing method," of Example 1. When stacking the pair of substrates, they were rotated so that the rubbing direction of the second substrate was perpendicular to the rubbing direction of the first substrate, and the liquid crystal cells were manufactured. Using the manufactured liquid crystal cells, the drive threshold voltage, maximum brightness voltage, cell transmittance, liquid crystal alignment, and liquid crystal response speed were evaluated using the same method as in Example 1. The results are shown in Table 6.

[0171] [Table 5]

[0172] [Table 6]

[0173] As shown in Table 6, in Examples 30 to 34, which used a liquid crystal alignment agent containing polymer (P) and compound (A), the driving voltage threshold, maximum brightness voltage, cell transmittance, liquid crystal alignment, and liquid crystal response speed evaluation were all "good (○)" or "acceptable (△)," demonstrating that various characteristics were improved in a balanced manner.

[0174] From these results, it has become clear that a liquid crystal alignment agent containing polymer (P) and compound (A) can be used to obtain a liquid crystal alignment film with high rubbing resistance and good low pre-tilt angle characteristics, as well as a liquid crystal element with a fast liquid crystal response speed, low driving voltage, and high transmittance.

Claims

1. A polymer (P) having a substructure composed of removing one or more hydrogen atoms from the ring portion of the structure represented by the following formula (1) (except for the fluorene ring in the 9-fluorenylmethyloxycarbonyl group), A compound (A) having a total of two or more groups in one molecule of at least one selected from the group consisting of an oxyranyl group, an oxetanyl group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, a protected isocyanate group, and a polymerizable carbon-carbon unsaturated bond group, and having no aromatic ring, It contains, The polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and has at least one selected from the group consisting of a substructure represented by the following formula (1-1A) and a substructure represented by the following formula (1-2A), and is a liquid crystal alignment agent. 【Chemistry 1】 (In formula (1), Ar １ and Ar ２ These are independently divalent aromatic ring groups. １ It consists of a single bond, an oxygen atom, a sulfur atom, and -NR １ - Or an alkanediyl group having 1 to 3 carbon atoms. ２ is, -NR １ - Or an alkanediyl group having 1 to 3 carbon atoms. １ (This is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally desorbable group.) 【Chemistry 2】 (In Formula (1-1A) and Formula (1-2A), A １ and A ２ are such that A １ is an (n1 + 1)-valent aromatic ring group and A ２ is an (n2 + 1)-valent aromatic ring group, or each of A １ and A ２ has an aromatic ring, and these aromatic rings are linked to each other by a single bond, an oxygen atom, a sulfur atom, -NR １ -, or an alkanediyl group having 1 to 3 carbon atoms to form a condensed ring structure. A ３ is an (n3 + 1)-valent aromatic ring group. Y １ is a nitrogen atom or a trivalent group in which a hydrogen atom, a methyl group or a hydroxyl group is bonded to a carbon atom. n1, n2 and n3 are each independently 1 or 2. Ar １ , Ar ２ , R １ and X １ are as defined in the above formula (1). "*" represents a bond.

2. The liquid crystal alignment agent according to claim 1, wherein the polymer (P) comprises a structural unit selected from the group consisting of a diamine having a substructure represented by formula (1-1A) and a diamine having a substructure represented by formula (1-2A).

3. The liquid crystal alignment agent according to claim 1, wherein the polymer (P) includes a structural unit derived from a tetracarboxylic dianhydride having a substructure represented by the above formula (1-1A).

4. The liquid crystal alignment agent according to claim 1, wherein the polymer (P) comprises structural units derived from an alicyclic tetracarboxylic dianhydride.

5. A polymer (P) having a substructure composed of removing one or more hydrogen atoms from the ring portion of the structure represented by the following formula (1) (except for the fluorene ring in the 9-fluorenylmethyloxycarbonyl group), A compound (A) having a total of two or more groups in one molecule of at least one selected from the group consisting of an oxyranyl group, an oxetanyl group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, a protected isocyanate group, and a polymerizable carbon-carbon unsaturated bond group, and having no aromatic ring, It contains, The polymer (P) is an addition polymer and has at least one selected from the group consisting of a substructure represented by the following formula (1-1B) and a substructure represented by the following formula (1-2B), and is a liquid crystal alignment agent. 【Transformation 3】 (In formula (1), Ar １ and Ar ２ These are independently divalent aromatic ring groups. １ It consists of a single bond, an oxygen atom, a sulfur atom, and -NR １ - Or an alkanediyl group having 1 to 3 carbon atoms. ２ is, -NR １ - Or an alkanediyl group having 1 to 3 carbon atoms. １ (This is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally desorbable group.) 【Chemistry 4】 (In equations (1-1B) and (1-2B), Ar １ Ar ２ and X １ This is equivalent to equation (1) above. Y １ This is either a nitrogen atom, or a trivalent group in which a hydrogen atom, a methyl group, or a hydroxyl group is bonded to a carbon atom. ４ This refers to a single bond, -CO-, -COO-, -CONH-, a divalent aromatic ring group, or a divalent group formed by the bonding of a divalent aromatic ring group with -CO-, -COO-, or -CONH-. (* indicates a bond with a carbon atom constituting the main chain of the polymer.)

6. A polymer (P) having a substructure composed of removing one or more hydrogen atoms from the ring portion of the structure represented by the following formula (1) (except for the fluorene ring in the 9-fluorenylmethyloxycarbonyl group), A compound (A) having a total of two or more groups in one molecule of at least one selected from the group consisting of an oxyranyl group, an oxetanyl group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, a protected isocyanate group, and a polymerizable carbon-carbon unsaturated bond group, and having no aromatic ring, It contains, The polymer (P) is a polyether and has a substructure represented by the following formula (1-1C), and is a liquid crystal alignment agent. 【Transformation 5】 (In formula (1), Ar １ and Ar ２ These are independently divalent aromatic ring groups. １ It consists of a single bond, an oxygen atom, a sulfur atom, and -NR １ - Or an alkanediyl group having 1 to 3 carbon atoms. ２ is, -NR １ - Or an alkanediyl group having 1 to 3 carbon atoms. １ (This is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally desorbable group.) 【Transformation 6】 (In formula (1-1C), A ５ and A ６ These are either independently divalent aromatic ring groups, or A ５ and A ６ Each of these has an aromatic ring, and these aromatic rings are bonded by a single bond, an oxygen atom, a sulfur atom, and -NR １ - Or it represents a fused ring structure composed of alkanediyl groups with 1 to 3 carbon atoms linked together. Ar １ Ar ２ , R １ and X １ This is equivalent to equation (1) above. "*" represents a coupling.

7. A polymer (P) having a substructure composed of removing one or more hydrogen atoms from the ring portion of the structure represented by the following formula (1) (except for the fluorene ring in the 9-fluorenylmethyloxycarbonyl group), A compound (A) having a total of two or more groups in one molecule of at least one selected from the group consisting of an oxyranyl group, an oxetanyl group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, a protected isocyanate group, and a polymerizable carbon-carbon unsaturated bond group, and having no aromatic ring, It contains, The polymer (P) is a polyester and has a substructure represented by the following formula (1-1C), and is a liquid crystal alignment agent. 【Transformation 7】 (In formula (1), Ar １ and Ar ２ These are independently divalent aromatic ring groups. １ It consists of a single bond, an oxygen atom, a sulfur atom, and -NR １ - Or an alkanediyl group having 1 to 3 carbon atoms. ２ is, -NR １ - Or an alkanediyl group having 1 to 3 carbon atoms. １ (This is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally desorbable group.) 【Transformation 8】 (In formula (1-1C), A ５ and A ６ These are either independently divalent aromatic ring groups, or A ５ and A ６ Each of these has an aromatic ring, and these aromatic rings are bonded by a single bond, an oxygen atom, a sulfur atom, and -NR １ - Or it represents a fused ring structure composed of alkanediyl groups with 1 to 3 carbon atoms linked together. Ar １ Ar ２ , R １ and X １ This is equivalent to equation (1) above. "*" represents a coupling.

8. A liquid crystal alignment agent according to any one of claims 1 to 7, comprising 30 mol% or more of structural units having a substructure composed of removing one or more hydrogen atoms from the ring portion of the structure represented by formula (1) above, relative to the total structural units constituting the polymer (P).

9. A liquid crystal alignment agent according to any one of claims 1 to 7, further comprising a polymer different from the polymer (P) mentioned above.

10. The compound (A) is a liquid crystal alignment agent according to any one of claims 1 to 7, represented by the following formula (2). 【Chemistry 9】 (In formula (2), B １ R is an oxyranyl group, an oxetanyl group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, a protected isocyanate group, or a polymerizable carbon-carbon unsaturated bond group. ５ This is an m-valence group consisting of a chain structure, an alicyclic structure, an aliphatic heterocyclic structure, or a combination of two or more of these. m is an integer from 2 to 10. Multiple B in the formula １ They are either identical or different from one another.

11. A step of forming a coating film using a liquid crystal alignment agent according to any one of claims 1 to 7, A step of applying a rubbing treatment to the aforementioned coating film to impart liquid crystal alignment ability, A method for manufacturing a liquid crystal alignment film, including the above.

12. A liquid crystal alignment film formed with the liquid crystal alignment agent described in any one of claims 1 to 7.

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

14. Equipped with a pair of substrates, The liquid crystal element according to claim 13, wherein a liquid crystal alignment film is formed on one of the pair of substrates using the liquid crystal alignment agent described in any one of claims 1 to 7, and a liquid crystal alignment film is formed on the other substrate using the liquid crystal alignment agent that does not contain the polymer (P).

15. Equipped with a pair of substrates, The liquid crystal element according to claim 13, wherein a liquid crystal alignment film is formed on each of the pair of substrates using the liquid crystal alignment agent described in any one of claims 1 to 7.

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