TW202344672A - Method for producing liquid crystal alignment film, photo-alignment agent, liquid crystal element, polymer, and diamine - Google Patents

Abstract

The invention provides a method for producing a liquid crystal alignment film, a photo-alignment agent, a liquid crystal element, a polymer, and a diamine. By means of the liquid crystal aligning agent, a liquid crystal aligning film with excellent liquid crystal aligning performance, key durability and sealing performance can be obtained, and a liquid crystal element with suppressed generation of bright spot defects can be manufactured. A liquid crystal alignment film is manufactured by a method including a step of forming a coating film from a liquid crystal alignment agent containing a polymer [A] having a partial structure (a) represented by formula (1); and a step in which the coating film is irradiated with light to impart liquid crystal aligning ability. In formula (1), A1 and A2 are divalent aromatic ring groups. And each of B1 and B2 represents a single bond,-O-,-S-,-NR5-,-CO-, * 1-CO-O-, * 1-O-CO-, * 1-CS-O-, * 1-O-CS-, * 1-CO-NR6-, or * 1-NR6-CO-NR7-. And X represents a divalent hydrocarbon group. *-A<SP>1</SP>-B<SP>1</SP>-X-B<SP>2</SP>-A<SP>2</SP>-* (1).

Description

Manufacturing method of liquid crystal alignment film, photoalignment agent, liquid crystal element, polymer and diamine

The invention relates to a manufacturing method of a liquid crystal alignment film, a photoalignment agent, a liquid crystal element, a polymer and a compound.

Liquid crystal elements are used in a wide range of applications, from relatively large display devices such as LCD televisions and information displays to small display devices such as smartphones. The performance of a liquid crystal element is determined by various characteristics such as the orientation of the liquid crystal, the size of the pretilt angle, and the voltage retention rate. In order to improve the performance of liquid crystal elements, in the past, in addition to improvements in liquid crystal materials, liquid crystal alignment films for aligning liquid crystals in a certain direction have been improved (for example, see Patent Document 1 and Patent Document 2).

Patent Document 1 discloses a liquid crystal alignment agent containing polyamide and its derivatives which are the reaction products of tetracarboxylic dianhydride and diamine, wherein the liquid crystal alignment agent contains di-tert-butyl { A polyamide obtained by using [hexanedilylbis(azanediyl)]bis(5-amino-2,1-phenylene)}diaminoformate as a diamine. In addition, Patent Document 2 discloses that a liquid crystal alignment agent is obtained by using 4,4'-[ethane-1,2-diylbis(oxy)]bis(3-methylaniline) as a diamine. of polyimide. [Prior art documents] [Patent Document]

[Patent Document 1] International Publication No. 2014/104015 [Patent Document 2] International Publication No. 2017/047596

[Problem to be solved by the invention] As a method of imparting anisotropy to a film to form a liquid crystal alignment film, there is a photo-alignment method. The photoalignment method is a method of controlling the alignment of liquid crystal molecules by irradiating a radiation-sensitive organic thin film formed on a substrate with polarized or non-polarized radiation to impart anisotropy to the film. According to this method, compared with the conventional rubbing method, the generation of dust or static electricity in the step can be suppressed, and therefore the occurrence of display defects or a decrease in yield caused by dust or the like can be suppressed. In addition, there is also an advantage that liquid crystal alignment ability can be uniformly imparted to the organic thin film formed on the substrate. On the other hand, when the photoalignment method is applied, decomposition products such as polymers are easily generated by light irradiation, and display defects (bright spots) caused by the decomposition products are likely to occur. In order to realize high-quality liquid crystal elements, it is required to have excellent liquid crystal alignment, which is one of the basic characteristics, and to suppress the occurrence of bright spots.

In mobile applications such as smartphones and tablet personal computers (PCs), efforts are being made to achieve narrower borders in order to further expand the working area of the touch panel while miniaturizing the display device. As one of the methods for achieving narrow bezels, a method is known in which a liquid crystal alignment film is formed on the entire substrate surface, a sealant is applied to the liquid crystal alignment film, and the substrates are bonded to each other. On the other hand, when a sealant is disposed on the liquid crystal alignment film, force is easily applied to the portion of the alignment film where the sealant is disposed. Therefore, if the mechanical properties or adhesion of the liquid crystal alignment film are low, the substrates may easily peel off from each other.

In addition, in recent years, among the liquid crystal elements used in smartphones and vehicles, the touch panel method has become the mainstream, which is susceptible to external force caused by the user's key operations. From the viewpoint of improving the reliability of liquid crystal elements, the liquid crystal alignment film constituting the liquid crystal element is also required to be less susceptible to deterioration in display quality due to external force and to have good key durability (also called touch panel durability).

The present invention is made in view of the above problems, and its main purpose is to provide a liquid crystal alignment agent that can obtain a liquid crystal alignment film with excellent liquid crystal alignment, key durability and adhesion and can prevent the occurrence of defective bright spots. Obtain suppressed liquid crystal element. [Technical means to solve problems]

In order to solve the said problem, this invention adopts the following means.

<1> A method for manufacturing a liquid crystal alignment film, including the steps of forming a coating film with a liquid crystal alignment agent containing a polymer [A] having a partial structure (a) represented by the following formula (1); and The coating film is irradiated with light to impart alignment ability to the liquid crystal. [Chemical 1] (In formula (1), A ¹ and A ² are each independently a divalent aromatic ring group; wherein, one or both of A ¹ and A ² have -OR ¹ , -NR ² R ³ or -SR ⁴ A structure in which the represented group is bonded to an aromatic ring; R ¹ , R ² and R ⁴ are independently hydrogen atoms or monovalent organic groups; R ³ is a monovalent organic group; B ¹ and B ² are independently For single bonds, -O-, -S-, -NR ⁵ -, -CO-, * ¹ -CO-O-, * ¹ -O-CO-, * ¹ -CS-O-, * ¹ -O- CS-, * ¹ -CO-NR ⁶ - or * ¹ -NR ⁶ -CO-NR ⁷ -; "* ¹ " represents the bond with A ¹ or A ² ; R ⁵ , R ⁶ and R ⁷ are independent Ground is a hydrogen atom or a monovalent organic group; X is a divalent hydrocarbon group; "*" indicates a bond)

<2> A photoalignment agent containing a polymer [A] having the partial structure (a) represented by the formula (1). <3> A liquid crystal element including a liquid crystal alignment film manufactured by the method of <1>. <4> A polymer containing a structural unit derived from a diamine represented by the following formula (3). [Chemicalization 2] (In formula (3), A ³ and A ⁴ are each independently a divalent aromatic ring group; wherein, one or both of A ³ and A ⁴ have a group represented by -OR ^1a or -NR ^2a R ^3a A structure bonded to an aromatic ring; R ^1a and R ^2a are each independently a monovalent hydrocarbon group; R ^3a is a hydrogen atom or a monovalent organic group; B ³ and B ⁴ are each independently a single bond, -O-, -S-, -NR ^5a -, -CO-, * ¹ -CO-O-, * ¹ -O-CO-, * ¹ -CS-O-, * ¹ -O-CS-, * ¹ -CO- NR ^6a - or * ¹ -NR ^6a -CO-NR ^7a -; R ^5a is a monovalent organic group; R ^6a and R ^7a are independently a hydrogen atom or a monovalent organic group; "* ¹ " means the same as A ³ or The bond of A ⁴ ; when B ³ is -O-, Y is an alkanediyl group with 1 or 2 carbon atoms, a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group, and when B ³ is * ¹ - In the case of O-CO-, Y is an alkanediyl group, a divalent alicyclic hydrocarbon group having an aliphatic hydrocarbon ring with 4 or more carbon atoms, or a divalent aromatic hydrocarbon group, and B ³ is -O- and * ¹ -O In the case other than -CO-, Y is a divalent hydrocarbon group) <5> A diamine represented by the above formula (3). [Effects of the invention]

According to the present invention, a liquid crystal alignment film excellent in liquid crystal alignment, key durability, and adhesion can be obtained, and a liquid crystal element in which the occurrence of defective bright spots is suppressed can be obtained.

Hereinafter, the manufacturing method of the liquid crystal alignment agent and the liquid crystal alignment film of the present disclosure will be described.

In addition, in this specification, the term "hydrocarbon group" means a linear hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The so-called "chain hydrocarbon group" refers to a linear hydrocarbon group and a branched hydrocarbon group that do not contain a cyclic structure in the main chain and are composed only of a chain structure. Among them, the chain hydrocarbon group may be saturated or unsaturated. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group containing only an alicyclic hydrocarbon structure as a ring structure and not containing an aromatic ring structure. Here, the alicyclic hydrocarbon group does not need to be composed only of the structure of an alicyclic hydrocarbon, but also includes a group having a chain structure in a part thereof. The "aromatic hydrocarbon group" refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. The aromatic hydrocarbon group does not need to be composed only of an aromatic ring structure, but may include a chain structure or an alicyclic hydrocarbon structure in a part thereof. "Aromatic ring" means an aromatic hydrocarbon ring and an aromatic heterocyclic ring. The “organic group” refers to an atomic group obtained by removing an arbitrary hydrogen atom from a compound containing carbon (that is, an organic compound).

<<Liquid crystal alignment agent>> The liquid crystal alignment agent of the present disclosure contains a polymer [A] having a partial structure (a) represented by the following formula (1). [Chemical 3] (In formula (1), A ¹ and A ² are each independently a divalent aromatic ring group; wherein, one or both of A ¹ and A ² have -OR ¹ , -NR ² R ³ or -SR ⁴ A structure in which the represented group is bonded to an aromatic ring; R ¹ , R ² and R ⁴ are independently hydrogen atoms or monovalent organic groups; R ³ is a monovalent organic group; B ¹ and B ² are independently For single bonds, -O-, -S-, -NR ⁵ -, -CO-, * ¹ -CO-O-, * ¹ -O-CO-, * ¹ -CS-O-, * ¹ -O- CS-, * ¹ -CO-NR ⁶ - or * ¹ -NR ⁶ -CO-NR ⁷ -; "* ¹ " represents the bond with A ¹ or A ² ; R ⁵ , R ⁶ and R ⁷ are independent Ground is a hydrogen atom or a monovalent organic group; X is a divalent hydrocarbon group; "*" indicates a bond)

The liquid crystal alignment agent of the present disclosure is particularly suitable as a liquid crystal alignment agent (ie, photoalignment agent) used to form a liquid crystal alignment film through photo alignment treatment. Hereinafter, first, each component contained in the liquid crystal alignment agent of the present disclosure and other components optionally blended as necessary will be described.

<Polymer [A]> ・About partial structure (a) In the formula (1), examples of the divalent aromatic ring group represented by A ¹ and A ² include a divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic ring. base. Examples of the divalent aromatic hydrocarbon group include groups obtained by removing any hydrogen atom bonded to a carbon atom constituting the ring of a benzene ring, a biphenyl ring, a naphthalene ring or an anthracene ring. Examples of the divalent nitrogen-containing aromatic heterocyclic group include groups in which any hydrogen atom bonded to a carbon atom constituting the ring of a pyridine ring, a pyrimidine ring, a pyridazine ring or a pyrazine ring is removed. Among these, the divalent aromatic ring group represented by A ¹ and A ² is preferably a divalent aromatic hydrocarbon group, and more preferably a group obtained by removing any hydrogen atom bonded to a carbon atom constituting the benzene ring.

One or both of A ¹ and A ² have an electron-donating group (hereinafter, also referred to as "substituent F1") represented by -OR ¹ , -NR ² R ³ or -SR ⁴ bonded to the aromatic ring. formed structure. By introducing a structure in which the substituent F1 is directly bonded to the aromatic ring into the polymer, the thermal rearrangement property is improved and the liquid crystal alignment is improved, or by the introduction of the substituent F1, the crystallinity is reduced and the stress is easily relaxed. From this, it can be inferred that the strength is improved and the durability of the key is improved. In addition, by introducing the substituent F1, the solubility of the polymer can be improved, and the polymer can be made highly sensitive.

From the viewpoint of fully obtaining the effect of improving liquid crystal alignment, the monovalent organic group represented by R ¹ , R ² , R ³ or R ⁴ is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms or a thermally detachable group, and more preferably It is preferably a monovalent hydrocarbon group having 1 to 6 carbon atoms or a thermally detachable group, and more preferably a monovalent hydrocarbon group having 1 to 5 carbon atoms or a thermally detachable group. Moreover, a thermally detachable group is a group which is detached by heat and substituted with a hydrogen atom. From the viewpoint of improving the detachability by heat and reducing the residual amount of the detached portion in the film, the thermal detachable group preferably has a carbon number of 15 or less, and more preferably a carbon number of 10 or less.

Specific examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms include an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and the like. Among these, a monovalent hydrocarbon group having 1 to 6 carbon atoms is preferred, an alkyl group or a phenyl group having 1 to 5 carbon atoms is more preferred, and an alkyl group having 1 to 3 carbon atoms is even more preferred.

Specific examples when R ¹ is a thermally deleasable group include: acetyl group, benzyl group, benzyl group, p-methoxyphenylbenzyl group, methoxymethyl, tert-butoxycarbonyl group, tris Methylsilyl, triethylsilyl, tert-butyldimethylsilyl, trityl, etc. Among these, the thermally detachable group represented by R ¹ is preferably an acetyl group, a methoxymethyl group or a tert-butoxycarbonyl group, and more preferably an acetyl group or a tert-butoxycarbonyl group (Boc group).

Specific examples when R ² and R ³ are thermally deleasable groups include: urethane-based protecting groups, amide-based protecting groups, amide-based protecting groups, amide-based protecting groups, and sulfonamides. Department of protective groups, etc. Among these, a urethane protecting group is preferred in terms of high thermal releasability. Specific examples thereof include: tert-butoxycarbonyl group, methoxycarbonyl group, benzyloxycarbonyl group, 1,1-dimethyl-2-haloethyloxycarbonyl group, allyloxycarbonyl group, 2-(Trimethylsilyl)ethoxycarbonyl, 9-fluorenylmethyloxycarbonyl, etc. Among these, a tert-butoxycarbonyl group (Boc group) is particularly preferred in that it is excellent in detachability by heat and can reduce the amount of the desorbed portion remaining in the film.

Specific examples when R ⁴ is a thermally deleasable group include benzyloxymethyl, p-methoxybenzyloxymethyl, tert-butoxycarbonyl group, trimethylsilyl group, and the like. Among these, a tert-butoxycarbonyl group (Boc group) is preferred.

From the viewpoint of improving liquid crystal alignment, among the above, R ¹ , R ² and R ⁴ are preferably a hydrogen atom, a monovalent hydrocarbon group having 1 to 6 carbon atoms or a thermally detachable group, and more preferably a hydrogen atom, a carbon An alkyl group with a number of 1 to 3, a phenyl group or a thermally detachable group. R ³ is preferably a monovalent hydrocarbon group having 1 to 6 carbon atoms or a thermally detachable group, and more preferably is an alkyl group having 1 to 3 carbon atoms, a phenyl group or a thermally detachable group.

Specific examples of the substituent F1 include: hydroxyl group, alkoxy group having 1 to 5 carbon atoms, alkylcarbonyloxy group having 2 to 5 carbon atoms (acetyloxy group, propyloxy group, etc.), tert-butyl group Oxycarbonyloxy group, alkylamino group having 1 to 5 carbon atoms, dimethylamino group, diethylamine group, alkylamide group having 2 to 5 carbon atoms, N-(tert-butoxycarbonyl) Amino, N-(tert-butoxycarbonyl)-N-methylamino, N-(tert-butoxycarbonyl)-N-ethylamino, N,N-bis(tert-butoxycarbonyl)amine group, thiol group, alkylthio group having 1 to 5 carbon atoms, etc.

In terms of improving the effect of improving liquid crystal alignment, the substituent F1 is preferably -OR ¹ or -NR ² R ³ , and more preferably -OR ¹ .

From the viewpoint of obtaining good liquid crystal alignment and adhesion effects, and increasing the effects of suppressing bright spots and improving key durability, it is preferable that both A ¹ and A ² have a substituent F1 bonded to an aromatic ring. . The number of substituents F1 in A ¹ and the number of substituents F1 in A ² are preferably 1 to 3, more preferably 1 or 2, and still more preferably 1.

The bonding position of the substituent F1 in the aromatic ring is not particularly limited. When the atom to which the substituent F1 is bonded is adjacent to the atom to which B ¹ or B ² (X when B ¹ and B ² are single bonds) is bonded, the sensitivity to light can be further improved. , a liquid crystal element showing good liquid crystal alignment can be obtained, which is suitable in this regard. Furthermore, A ¹ and A ² preferably do not have a substituent different from the substituent F1 in the ring portion of the aromatic ring.

Regarding B ¹ and B ² , R ⁵ , R ⁶ or R ⁷ contained in -NR ⁵ -, * ¹ -CO-NR ⁶ -, * ¹ -NR ⁶ -CO-NR ⁷ - is a monovalent organic group. In the case of , the monovalent organic group is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms or is thermally detachable. Specific examples and preferred examples of R ⁵ , R ⁶ or R ⁷ being a monovalent hydrocarbon group or a thermally detachable group having 1 to 10 carbon atoms include the groups described as specific examples and preferred examples of R ² and R ³ . R ⁵ , R ⁶ and R ⁷ are preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a thermally detachable group, and more preferably are an alkyl group having 1 to 3 carbon atoms or a tert-butoxycarbonyl group.

From the viewpoint of obtaining a liquid crystal element exhibiting good liquid crystal alignment, B ¹ and B ² are preferably -O-, -S-, -NR ⁵ -, -CO-, * ¹ -CO-O-. , * ¹ -O-CO-, * ¹ -CS-O-, * ¹ -O-CS-, * ¹ -CO-NR ⁶ - or * ¹ -NR ⁶ -CO-NR ⁷ -, more preferably - O-, -S- or -NR ⁵ -.

Examples of the divalent hydrocarbon group represented by X include a chain hydrocarbon group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and an aromatic hydrocarbon group having 6 to 18 carbon atoms. X is preferably a chain hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or an alicyclic hydrocarbon group having 6 carbon atoms, in order to form a liquid crystal alignment film with a high effect of improving liquid crystal alignment and key durability. The aromatic hydrocarbon group having 1 to 12 carbon atoms is more preferably a linear alkanediyl group with 1 to 5 carbon atoms, and even more preferably a methylene group, in terms of improving liquid crystal alignment or increasing film density. Or 1,2-ethylene.

In order to further enhance the effect of improving liquid crystal alignment and key durability, the polymer [A] preferably has a partial structure (a) in the main chain, that is, the partial structure (a) constitutes the polymer [A]. part of the main chain. The main skeleton of the polymer [A] is not particularly limited. Polymerization is easy to introduce partial structure (a) into the main chain of the polymer, can form a liquid crystal alignment film with high affinity for liquid crystals and high mechanical strength, and has a high degree of freedom in selecting monomers. Substance [A] preferably has a structural unit derived from a diamine containing partial structure (a) (hereinafter, also referred to as "specific diamine"). Specifically, it is preferred that it has a structural unit derived from the following formula (2). represents the structural unit of the compound. [Chemical 4] (In formula (2), A ¹ , A ² , B ¹ , B ² and X have the same meaning as in formula (1))

Here, the "main chain" refers to the "backbone" part including the longest atomic chain in the polymer. Furthermore, the "backbone" portion is allowed to contain ring structures. That is, "having partial structure (a) in the main chain" means that partial structure (a) forms part of the main chain. The so-called "side chain" refers to the part branching from the "backbone" of the polymer.

The specific diamine is particularly preferably a compound represented by the following formula (2A). [Chemistry 5] (In formula (2A), Z ¹ and Z ² are each independently a group represented by -OR ¹ , -NR ² R ³ or -SR ⁴ ; k1 and k2 are each independently 1 or 2; when k1 is 2 In this case, multiple Z ¹ are the same or different; when k2 is 2, multiple Z ² are the same or different; R ¹ , R ² , R ³ , R ⁴ , B ¹ , B ² and X are consistent with the above formula (1) has the same meaning)

In formula (2A), Z ¹ and Z ² are preferably groups represented by -OR ¹ or -NR ² R ³ .

When Z ¹ and Z ² are groups represented by -OR ¹ , R ¹ is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group or a thermally detachable group, and more preferably is a group having 1 to 5 carbon atoms. an alkyl group, and more preferably an alkyl group having 1 to 3 carbon atoms. In addition, B ¹ and B ² are preferably -O-, -S-, -NR ⁵ -, -CO-, * ¹ -CO-O-, * ¹ -O-CO-, * ¹ -CS-O-, * ¹ -O-CS-, * ¹ -CO-NR ⁶ - or * ¹ -NR ⁶ -CO-NR ⁷ -, more preferably -O-, -S- or -NR ⁵ -. X is preferably an alkanediyl group having 1 or 2 carbon atoms, a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group, and more preferably is an alkanediyl group having 1 or 2 carbon atoms.

When Z ¹ and Z ² are groups represented by -NR ² R ³ , R ² is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a phenyl group or a thermally detachable group, and R ³ is preferably a carbon number 1 to 3 alkyl groups, phenyl groups or thermally detachable groups. In addition, B ¹ and B ² are preferably -O-, -S- or -NR ⁵ -, and more preferably -O-. X is preferably an alkanediyl group having 1 to 5 carbon atoms, a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group, more preferably an alkanediyl group having 1 to 5 carbon atoms, and still more preferably an alkanediyl group having 1 or 2 carbon atoms. base.

Specific examples of the specific diamine include compounds represented by the following formulas (4-1) to (4-24). In addition, in the formula, "Boc" represents a tert-butoxycarbonyl group (the same applies below). [Chemical 6] [Chemical 7] [Chemical 8] (In the formula, n is an integer from 1 to 18)

In the compounds represented by the formulas (4-1) to (4-24), the bonding position of the substituent F1 on the benzene ring is not particularly limited. The bonding position of the substituent F1 is preferably relative to a group other than the primary amine group (that is, B ¹ or B ² (X when B ¹ and B ² are single bonds) in the formula (1)) ) instead of 2-digit or 3-digit. In particular, when the bonding position of the substituent F1 is 2-position with respect to groups other than the primary amine group, it is preferable in that high sensitivity can be achieved and liquid crystal alignment can be further improved.

In polymer [A], from the viewpoint of sufficiently improving the liquid crystal alignment, adhesion, and key durability of the liquid crystal alignment film and obtaining a liquid crystal element in which the generation of bright spots is sufficiently suppressed, compared to polymerization The content ratio of the structural unit having partial structure (a) (hereinafter also referred to as "structural unit (Ua)") is preferably 2 mole parts per 100 mole parts in total of the monomer units contained in substance [A] above. The content ratio of the structural unit (Ua) is more preferably 5 mole parts or more, further preferably 10 mole parts or more, based on 100 mole parts of the total amount of monomer units contained in the polymer [A]. In addition, the content ratio of the structural unit (Ua) can be appropriately set according to the main chain of the polymer [A]. It is, for example, 50 mole parts per 100 mole parts of the total amount of the monomer units of the polymer [A]. portion or less. In addition, the number of structural units (Ua) that the polymer [A] has may be only one type or two or more types.

Specific diamines can be synthesized by appropriately combining conventional methods of organic chemistry. As an example, the following method can be cited: synthesizing a dinitroform having a nitro group in place of the primary amine group of the diamine having partial structure (a), and then using an appropriate reduction system to reduce the nitro group of the obtained dinitroform. Amination.

The method of synthesizing dinitroforms can be appropriately selected depending on the target compound. For example, it is preferable to react a hydroxyl-containing compound having an aromatic ring structure to which substituent F1 is bonded and a halide having a group X in an organic solvent in the presence of a base and an optional catalyst; preferably, A method of reacting a hydroxyl-containing compound having an aromatic ring structure bonded with substituent F1 and a toluenesulfonyl-containing compound having a base X in an organic solvent in the presence of a base and an optional catalyst; preferably A method of condensing an acid halide with an aromatic ring structure having a substituent F1 and an amine-containing compound having a group A method in which a carboxylic acid with an aromatic ring structure and an amine-containing compound having a group X are condensed in an organic solvent in the presence of a base and an optional catalyst, etc.

The reduction reaction of the dinitroform is preferably carried out in an organic solvent using a catalyst such as palladium carbon, platinum oxide, zinc, iron, tin, or nickel. Examples of the organic solvent used here include ethyl acetate, toluene, tetrahydrofuran, alcohols, and the like. Among them, the synthesis scheme of the specific diamine is not limited to the above method.

Through this disclosure, a diamine represented by the following formula (3) can be provided. [Chemical 9] (In formula (3), A ³ and A ⁴ are each independently a divalent aromatic ring group; wherein, one or both of A ³ and A ⁴ have a group represented by -OR ^1a or -NR ^2a R ^3a A structure bonded to an aromatic ring; R ^1a and R ^2a are each independently a monovalent hydrocarbon group; R ^3a is a hydrogen atom or a monovalent organic group; B ³ and B ⁴ are each independently a single bond, -O-, -S-, -NR ^5a -, -CO-, * ¹ -CO-O-, * ¹ -O-CO-, * ¹ -CS-O-, * ¹ -O-CS-, * ¹ -CO- NR ^6a - or * ¹ -NR ^6a -CO-NR ^7a -; R ^5a is a monovalent organic group; R ^6a and R ^7a are independently a hydrogen atom or a monovalent organic group; "* ¹ " means the same as A ³ or The bond of A ⁴ ; when B ³ is -O-, Y is an alkanediyl group with 1 or 2 carbon atoms, a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group, and when B ³ is * ¹ - In the case of O-CO-, Y is an alkanediyl group, a divalent alicyclic hydrocarbon group having an aliphatic hydrocarbon ring with 4 or more carbon atoms, or a divalent aromatic hydrocarbon group, and B ³ is -O- and * ¹ -O In the case other than -CO-, Y is a divalent hydrocarbon group)

In the formula (3), specific examples and preferred examples of the monovalent hydrocarbon group represented by R ^1a and R ^2a and the monovalent organic group represented by R ^3a include R in the formula (1). Specific examples and preferred examples of the monovalent hydrocarbon group and monovalent organic group exemplified by ¹ , ^R2 and ^R3 are the same. R ^1a and R ^2a are preferably a monovalent hydrocarbon group having 1 to 6 carbon atoms, more preferably an alkyl group and a phenyl group having 1 to 5 carbon atoms, and still more preferably an alkyl group having 1 to 3 carbon atoms. R ^3a is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group or a thermally detachable group, and more preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a tert-butoxycarbonyl group.

Regarding specific examples and preferred examples of B ³ and B ⁴ , the description of B ¹ and B ² in formula (1) can be applied. Specific examples of the divalent hydrocarbon group represented by Y include the same groups as those exemplified as the group represented by X in Formula (1).

When B ³ is -O-, from the viewpoint of improving the effect of improving liquid crystal alignment, Y is preferably an alkylenediyl group having 1 or 2 carbon atoms or a divalent alkyldiyl group having an aliphatic hydrocarbon ring having 4 or more carbon atoms. Alicyclic hydrocarbon group or divalent aromatic hydrocarbon group. The bivalent alicyclic hydrocarbon group having an aliphatic hydrocarbon ring having 4 or more carbon atoms preferably has a cyclohexane ring from the viewpoint of achieving good liquid crystal alignment and high film density. When B ³ is -O-, among these, Y is more preferably methylene or ethylene.

When B ³ is * ¹ -O-CO-, Y is preferably a linear alkanediyl group having 1 to 5 carbon atoms, and more preferably is a methylene or ethylene group. When B ³ is other than -O- and * ¹ -O-CO-, Y is preferably a chain hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or an alicyclic hydrocarbon group having 6 to 12 carbon atoms. The aromatic hydrocarbon group is more preferably a linear alkanediyl group having 1 to 5 carbon atoms, and further preferably methylene or ethylene, in terms of improving liquid crystal alignment and improving film density. base.

The diamine represented by formula (3) is particularly preferably a compound represented by the following formula (3A). [Chemical 10] (In formula (3A), Z ³ and Z ⁴ are each independently a group represented by -OR ^1a or -NR ^2a R ^3a ; k3 and k4 are each independently 1 or 2; when k3 is 2, multiple Z ³ is the same or different; when k4 is 2, Z ⁴ is the same or different; R ^1a , R ^2a , R ^3a , B ³ , B ⁴ and Y have the same meaning as the formula (3))

Specific examples of the diamine represented by formula (3) include the formulas (4-1) to (4-3), formula (4-6), formula (4-10) and formula ( 4-23) Compounds in which n is 1 or 2; compounds represented by formula (4-13), formula (4-18) and formula (4-22), etc.

Among them, the polymer [A] is preferably selected from the group consisting of polyamide acid, polyamide ester, and polyamide, in terms of forming a liquid crystal alignment film that has high affinity for liquid crystals, high mechanical strength, and high reliability. At least one of the group consisting of amines.

·Polyamide When the polymer [A] is a polyamic acid, the polyamic acid (hereinafter, also referred to as "polyamic acid [A]") can be obtained by mixing a tetracarboxylic dianhydride and a specific diamine. Obtained from the reaction of diamine compounds.

(tetracarboxylic dianhydride) Examples of the tetracarboxylic dianhydride used for the synthesis of polyamide [A] include aliphatic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, and the like. Examples of aliphatic tetracarboxylic dianhydride include chain tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride.

Specific examples of these include, as chain tetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, ethylenediaminetetraacetic dianhydride, and the like. Examples of alicyclic tetracarboxylic dianhydride include: 1,2,3,4-cyclobutanetetracarboxylic dianhydride, substituted cyclobutanetetracarboxylic dianhydride, and 2,3,5-tricarboxycyclopentanol Acetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-Tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, etc., 3 ,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, etc.

Examples of the aromatic tetracarboxylic dianhydride include: pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol bistrimellitic anhydride, and 4,4'- Carbonyl diphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, etc. In addition, as the tetracarboxylic dianhydride used for the synthesis of polyamide [A], the tetracarboxylic dianhydride described in Japanese Patent Application Laid-Open No. 2010-97188 can be used. As the tetracarboxylic dianhydride, one type may be used alone or two or more types may be used in combination.

In order to obtain a liquid crystal alignment film that has high solubility and exhibits good liquid crystal alignment and electrical properties, the tetracarboxylic acid didioic acid used in the synthesis of polyamide [A] (and thus polymer [A]) The anhydride preferably contains aliphatic tetracarboxylic dianhydride, and more preferably contains alicyclic tetracarboxylic dianhydride. The ratio of the structural units derived from the aliphatic tetracarboxylic dianhydride in the polymer [A] relative to the total amount of the structural units derived from the tetracarboxylic dianhydride contained in the polymer [A] is preferably 20 moles. % or more, more preferably 40 mol% or more, still more preferably 50 mol% or more.

Among them, the polymer [A] is preferably a polymer derived from a substituted cyclobutane in terms of producing a polymer with excellent photoalignment properties and reducing the occurrence of bright spots even after the photoalignment treatment by using it in combination with a specific diamine. Structural unit of tetracarboxylic dianhydride. Specifically, the polymer [A] preferably contains a structural unit having a partial structure represented by the following formula (4). [Chemical 11] (In formula (4), R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are each independently a hydrogen atom or a substituent; wherein, more than one of R ¹¹ , R ¹² , R ¹³ and R ¹⁴ is a substituent; "*" indicates bonding key)

In the formula (4), as the substituent represented by R ¹¹ , R ¹² , R ¹³ and R ¹⁴ (that is, the substituent possessed by the substituted cyclobutane tetracarboxylic dianhydride), carbon number 1 to 6 alkyl groups, halogenated alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, halogenated alkoxy groups having 1 to 6 carbon atoms, halogen atoms, etc. Among these, the substituent represented by R ¹¹ , R ¹² , R ¹³ and R ¹⁴ is preferably an alkyl group having 1 to 3 carbon atoms, a halogenated alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms. The halogenated alkoxy group or halogen atom having 1 to 3 carbon atoms is more preferably an alkyl group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, or a fluorine atom, and a methyl group is particularly preferred.

Specific examples of tetracarboxylic dianhydride having a partial structure represented by formula (4) include: 1-methyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3- Dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2, 3-Trimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride Anhydride, 1-ethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-diethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1 -Ethyl-3-methyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethoxy-1,2,3,4-cyclobutanetetracarboxylic dianhydride Anhydride, 1,3-diethoxy-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1-trifluoromethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride Anhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-bis(trifluoromethoxy)-1,2,3, 4-cyclobutanetetracarboxylic dianhydride, 1,2,3-tris(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4- Tetrakis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic dianhydride, etc.

In the case where the polymer [A] contains a structural unit derived from a substituted cyclobutane tetracarboxylic dianhydride, the source is The ratio of the structural units of the self-substituted cyclobutane tetracarboxylic dianhydride is preferably 20 mol% or more, more preferably 40 mol% or more, and still more preferably 60 mol% or more.

(diamine compound) The diamine compound used for the synthesis of polyamide [A] may be only a specific diamine, or a specific diamine and a diamine not having partial structure (a) may be used together (hereinafter also referred to as "others"). diamine"). Examples of other diamines include aliphatic diamines, aromatic diamines, diaminoorganosiloxanes, and the like. Examples of aliphatic diamines include chain diamines and alicyclic diamines.

Specific examples of other diamines include: chain diamines: meta-xylylenediamine, hexamethylenediamine, etc.; examples of alicyclic diamines: 1,4-diaminocyclic Hexane, 4,4'-methylenebis(cyclohexylamine), etc.; aromatic diamines include: p-phenylenediamine, 1,4-diamino-2,5-dimethylbenzene, 4, 4'-Diaminodiphenylmethane, 4,4'-Diaminodiphenylethane, 4-Aminophenyl-4-aminobenzoate, 4,4'-Diaminocou Nitrobenzene, 3,5-diaminobenzoic acid, 1,5-bis(4-aminophenoxy)pentane, 1,2-bis(4-aminophenoxy)ethane, 1,3 -Bis(4-aminophenoxy)propane, 1,6-bis(4-aminophenoxy)hexane, 6,6'-(pentamethylenedioxy)bis(3-amino) Pyridine), N,N'-bis(5-amino-2-pyridyl)-N,N'-bis(tert-butoxycarbonyl)ethylenediamine, bis[2-(4-aminophenyl) Ethyl]adipic acid, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenylurea, 2,2 -Bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,4-bis(4-aminophenoxy) Benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-(phenylenebis Isopropylidene)bisaniline, 2,6-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminotriazole, N-methyl-3,6-diaminotriazole , 3,6-diaminoacridine, a monomer containing a diphenylamine structure, a compound represented by the following formula (D-1), and other main chain diamines; [Chemical 12] (In formula (D-1), R ²¹ and R ²² are each independently an alkanediyl group; R ²³ is a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, or a thermally detachable group; n1 is an integer from 1 to 3; When n1 is 2 or 3, a plurality of R ²² are the same as or different from each other, and a plurality of R ²³ are the same as or different from each other) Hexadecyloxy-2,4-diaminobenzene, octadecyloxy-2 ,4-diaminobenzene, octadecyloxy-2,5-diaminobenzene, cholestyloxy-3,5-diaminobenzene, cholestyloxy-3,5-diamine Aminobenzene, cholestyloxy-2,4-diaminobenzene, cholestyloxy-2,4-diaminobenzene, cholestyl 3,5-diaminobenzoate, 3,5-Diaminobenzoic acid cholesteryl ester, 3,5-diaminobenzoic acid lanostanyl alkyl ester, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 3,5-diaminobenzoic acid=5ξ-cholestan-3-yl, Side chain diamines such as compounds represented by the following formula (E-1); [Chemical 13] (In formula (E-1), X ^{I and} bond); R ^I is an alkanediyl group having 1 to 3 carbon atoms; R ^II is a single bond or an alkyl diyl group having 1 to 3 carbon atoms; R ^III is an alkyl group, alkoxy group, or fluorine group having 1 to 20 carbon atoms Alkyl or fluoroalkoxy group; 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; among them, 1≦a+b+c≦3) diamine Examples of base organosiloxane include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane and the like.

Examples of the compound represented by the formula (D-1) include compounds represented by the following formulas (D-1-1) to (D-1-3). Examples of the compound represented by the formula (E-1) include compounds represented by the following formulas (E-1-1) to formula (E-1-4). As other diamines, one type may be used alone or two or more types may be used in combination. [Chemical 14]

Among polyamide [A], from the viewpoint of fully improving the liquid crystal alignment, adhesion, and key durability improvement effects of the liquid crystal alignment film and fully suppressing the occurrence of bright spots in the liquid crystal element, compared to those derived from polyamide The total amount of structural units in the diamine compound of the amino acid [A] and the proportion of structural units derived from the specific diamine are preferably 5 mol% or more, more preferably 10 mol% or more, and still more preferably 15 More than mol%. As the specific diamine, one type may be used alone, or two or more types may be used in combination.

·Synthesis of polyamide Polyamide [A] can be obtained by reacting a tetracarboxylic dianhydride and a diamine compound with a molecular weight regulator if necessary. In the synthesis reaction of polyamide [A], the usage ratio of tetracarboxylic dianhydride and diamine compound is preferably 0.2 to 0.2 equivalent to the acid anhydride group of tetracarboxylic dianhydride with respect to 1 equivalent of the amine group of the diamine compound. 2 equivalent ratio. Examples of the molecular weight adjuster include: acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; phenyl isocyanate, isocyanate; Naphthyl acid naphthyl ester and other monoisocyanate compounds, etc. The usage ratio of the molecular weight regulator is preferably 20 parts by mass or less relative to 100 parts by mass in total of the tetracarboxylic dianhydride and the diamine compound used.

The synthesis reaction of polyamide [A] is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20°C to 150°C, and the reaction time is preferably 0.1 hour to 24 hours. Examples of the organic solvent used for the reaction include aprotic polar solvents, phenol solvents, alcohol solvents, ketone solvents, ester solvents, ether solvents, halogenated hydrocarbons, hydrocarbons, and the like. As specific examples of these, it is preferable to use one selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsyanide, and γ- One or more of the group consisting of butyrolactone, tetramethylurea, hexamethylphosphonotriamine, m-cresol, xylenol and halogenated phenol is used as the reaction solvent, or one or more of these solvents are used together with other organic Mixture of solvents (such as butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount of the organic solvent used is preferably an amount such that the total amount of tetracarboxylic dianhydride and diamine becomes 0.1% by mass to 50% by mass relative to the total amount of the reaction solution.

Through the above reaction, a polymer solution in which polyamide [A] is dissolved can be obtained. The polymer solution can be directly used for the preparation of the liquid crystal alignment agent, or can be used for the preparation of the liquid crystal alignment agent after the polyamide [A] contained in the polymer solution is separated.

·Polyamide When the polymer [A] is a polyamic acid ester, the polyamic acid ester (hereinafter also referred to as "polyamic acid ester [A]") can be obtained by, for example, the following method: [ I] A method of reacting polyamide [A] and an esterifying agent; [II] A method of reacting a tetracarboxylic acid diester with a diamine compound containing a specific diamine; [III] A method of reacting a tetracarboxylic acid diester with a diamine compound containing a specific diamine; A method of reacting halides with diamine compounds containing specific diamines. The polyamic acid ester [A] may have only a amino acid ester structure, or may be a partially esterified product in which a amino acid structure and a amino acid ester structure coexist. The reaction solution obtained by dissolving the polyamide ester [A] can be directly used for the preparation of the liquid crystal alignment agent, or can be used for the liquid crystal alignment agent after separating the polyamide ester [A] contained in the reaction solution. preparation.

·Polyimide When the polymer [A] is a polyimide, the polyimide (hereinafter also referred to as "polyimide [A]") can be obtained by, for example, modifying the polyimide synthesized in the above manner. Acid [A] is obtained by dehydration, ring closure and imidization. The polyamide imide [A] may be a complete amide imide in which all the amide acid structures of the polyamide acid [A] as its precursor are dehydrated and cyclically closed, or it may be a amide acid structure. A partial amide imide with only a part of the ring closed by dehydration and a amide acid structure and an amide imine ring structure coexisting. The polyimide [A] preferably has an imidization rate of 20% to 99%, and more preferably 30% to 90%. In addition, the acyl imidization rate expresses as a percentage the ratio of the number of amide imine ring structures to the total number of amide acid structures and the number of amide imine ring structures of the polyamide imide. Here, a part of the acyl imine ring may be an isoamide imine ring.

Dehydration and ring-closure of polyamide [A] is preferably performed by dissolving polyamide [A] in an organic solvent, adding a dehydration agent and a dehydration ring-closure catalyst to the solution, and heating as necessary. In this method, as the dehydrating agent, for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. The usage amount of the dehydrating agent is preferably 0.01 mole to 20 mole relative to 1 mole of the amide acid structure of the polyamide [A]. As the dehydration ring-closure catalyst, for example, tertiary amines such as pyridine, tripyridine, dipyridine, and triethylamine can be used. The usage amount of the dehydration ring-closure catalyst is preferably 0.01 mole to 10 mole relative to 1 mole of the dehydrating agent used. Examples of the organic solvent used in the dehydration ring-closure reaction include organic solvents exemplified as organic solvents used for synthesizing polyamide [A]. The reaction temperature of the dehydration ring-closure reaction is preferably 0°C to 180°C. The reaction time is preferably 1.0 hours to 120 hours. In addition, the reaction solution containing polyimide [A] can be directly used for the preparation of the liquid crystal alignment agent, or the polyimide [A] can be separated and used for the preparation of the liquid crystal alignment agent.

Among them, polyimide [A] can be preferably used as the polymer [A] in terms of further improving the mechanical strength of the liquid crystal alignment film. Based on the research of the present inventors, when polyamide is imidized, the mechanical strength of the liquid crystal alignment film tends to decrease or the adhesiveness tends to decrease. On the other hand, the solubility of polyimide is lower than that of polyamide acid, and there is a risk that it may easily cause poor coating properties, uneven film, etc. In this regard, the polyimide [A] having the partial structure (a) exhibits good solubility and therefore can form a liquid crystal alignment film with high mechanical strength while suppressing a decrease in coatability or film uniformity. .

When preparing a solution with a concentration of 10 mass %, the solution viscosity of the polymer [A] used in the preparation of the liquid crystal alignment agent is preferably a solution viscosity of 10 mPa·s to 800 mPa·s, and more preferably a solution viscosity of 15 mPa·s. Solution viscosity from s to 500 mPa·s. In addition, the solution viscosity (mPa·s) is for a polymer solution with a concentration of 10% by mass prepared using a good solvent for polymer [A] (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) , measured using an E-type rotational viscometer at 25°C.

The polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the polymer [A] is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. In addition, the molecular weight distribution (Mw/Mn) represented by the ratio of Mw to the polystyrene-reduced number average molecular weight (Mn) measured by GPC is preferably 7 or less, and more preferably 5 or less. In addition, when preparing a liquid crystal alignment agent, as the polymer [A], one type may be used alone, or two or more types may be used in combination.

＜Other ingredients＞ In addition to the polymer [A], the liquid crystal alignment agent may also contain components different from the polymer [A] (hereinafter, also referred to as "other components") if necessary.

·Polymer[B] The liquid crystal alignment agent of the present disclosure may further contain a polymer that does not have partial structure (a) (hereinafter, also referred to as “polymer [B]”) as a polymer component. The main skeleton of the polymer [B] is not particularly limited. Examples of other polymers include polyamide acid, polyamide ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, and polyamide. Aminoimine, polybenzoxazole precursor, polybenzoxazole, cellulose derivatives, polyacetal, (meth)acrylic polymer, styrenic polymer, maleimide polymerization Materials, styrene-maleimide copolymers, etc. From the viewpoint of obtaining a highly reliable liquid crystal element, the polymer [B] is preferably selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and polymers having polymerizability. At least one of the group consisting of polymers of structural units of monomers with unsaturated carbon-carbon bonds. Examples of the polymer containing a structural unit derived from a monomer having a polymerizable unsaturated carbon-carbon bond include (meth)acrylic polymers, styrene polymers, maleimide polymers, and Styrene-maleimide copolymer, etc.

When the liquid crystal alignment agent contains polymer [B], the content ratio of polymer [B] relative to the total amount of polymer [A] and polymer [B] is preferably 1 mass % or more, more preferably It is 2 mass % or more. In addition, the content ratio of polymer [B] is preferably 95 mass % or less, and more preferably 90 mass % or less relative to the total amount of polymer [A] and polymer [B]. As the polymer [B], one type can be used alone or two or more types can be used in combination.

·Solvent The liquid crystal alignment agent of the present disclosure is prepared as a liquid composition in which polymer [A] and other optional components are preferably dispersed or dissolved in an appropriate solvent.

As the solvent, an organic solvent can be preferably used. Specific examples thereof include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolinone, and 1,3-dimethyl-2-pyrrolidone. Imidazolinone, phenol, γ-butyrolactone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl- 2-Pentanone, diacetone alcohol, 1-hexanol, 2-hexanol, propane-1,2-diol, 3-methoxy-1-butanol, ethylene glycol monomethyl ether, methyl lactate, Ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl acetate, ethyl acetate, ethyl propionate, methyl methoxypropionate, ethoxypropionate Ethyl ester, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-isopropyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, Ethylene glycol ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, Ethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisoamyl ether, ethylene carbonate, propylene carbonate, propylene glycol monomethyl ether (propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentanone, cyclohexanone, etc. As the solvent, one type may be used alone or two or more types may be mixed and used.

As other components contained in the liquid crystal alignment agent, in addition to the above, examples include: cross-linking agents, antioxidants, metal chelate compounds, hardening accelerators, surfactants, fillers, dispersants, and photosensitizers. Agents, etc. The blending ratio of other components can be appropriately selected for each compound within a range that does not impair the effects of the present disclosure.

The solid component concentration in the liquid crystal alignment agent (the ratio of the total mass of components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected considering viscosity, volatility, etc. The solid content concentration of the liquid crystal alignment agent is preferably in the range of 1% by mass to 10% by mass. If the solid content concentration is 1 mass % or more, the film thickness of the coating film can be sufficiently ensured and a liquid crystal alignment film showing better liquid crystal alignment properties can be obtained, which is suitable in this regard. On the other hand, if the solid content concentration is 10 mass % or less, the coating film can be made to an appropriate thickness, and a liquid crystal alignment film showing good liquid crystal alignment properties tends to be easily obtained. In addition, the viscosity of the liquid crystal alignment agent tends to be reduced. The properties become moderate and the coating properties are good.

"Liquid crystal alignment film and manufacturing method thereof" The liquid crystal alignment film of the present disclosure can be manufactured by the liquid crystal alignment agent prepared in the above manner. The liquid crystal alignment film of the present disclosure can preferably be produced by a method that includes the steps of forming a coating film with a liquid crystal alignment agent containing polymer [A] (coating film forming step); and subjecting the coating film to The step of imparting alignment ability to liquid crystal by irradiating light (photo-alignment treatment step).

·Coating film formation steps When manufacturing a liquid crystal alignment film, first, a liquid crystal alignment agent is coated on a substrate, and preferably the coating surface is heated to form a coating film on the substrate. As the substrate, for example, glass such as float glass and soda glass may be used; polyethylene terephthalate, polybutylene terephthalate, polyether terephthalate, polycarbonate, and poly(alicyclic olefin) may be used. Plastic transparent substrate.

The method of applying the liquid crystal alignment agent to the substrate is not particularly limited. The liquid crystal alignment agent can be applied to the substrate by, for example, spin coating, printing (for example, offset printing, flexographic printing, etc.), inkjet, slit coating, rod coater, extrusion die ) method, direct gravure coater method, chamber doctor coater method, offset gravure coater method, dip coater method, MB coater method, etc.

After applying the liquid crystal alignment agent, it is preferable to perform preheating (prebaking) for the purpose of preventing the applied liquid crystal alignment agent from sagging. The pre-baking temperature is preferably 30°C to 200°C, and the pre-baking time is preferably 0.25 minutes to 10 minutes. Then, the solvent is completely removed, and if necessary, a calcination (post-baking) step is performed for the purpose of thermally imidizing the amide structure present in the polymer. The calcination temperature (post-baking temperature) at this time is preferably 80°C to 280°C, more preferably 80°C to 250°C. The post-baking time is preferably 5 minutes to 200 minutes. The film thickness of the formed film is preferably 0.001 μm to 1 μm.

·Photo-alignment processing steps Next, the coating film formed by the above steps is subjected to a photo-alignment process, which is a process in which the coating film is irradiated with light (radiation irradiation) to impart alignment ability to the liquid crystal. Thus, a photo alignment film can be obtained. Light irradiation for photo-alignment can be performed by the following methods: irradiating the coating film after the post-baking step; irradiating the coating film after the pre-baking step and before the post-baking step; A method of irradiating the coating film during the heating process of the coating film in either or both of the pre-baking step and the post-baking step.

As the radiation irradiated to the coating film, for example, ultraviolet rays and visible rays including light having a wavelength of 150 nm to 800 nm can be used. Ultraviolet rays containing light with a wavelength of 200 nm to 400 nm are preferred. When the radiation is polarized light, it may be linearly polarized light or partially polarized light. When the radiation used is linearly polarized light or partially polarized light, the irradiation may be performed from a direction perpendicular to the substrate surface, an oblique direction, or a combination of these directions. In the case of non-polarized radiation, the irradiation direction is an oblique direction.

Examples of the light source used include a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, and the like. The irradiation dose of radiation is preferably 200 J/m ² to 30,000 J/m ² , more preferably 500 J/m ² to 10,000 J/m ² . After the light irradiation for imparting alignment ability, the substrate surface may also be treated with water, organic solvent (for example, methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.) or a mixture thereof, or the substrate is heated.

"Liquid Crystal Component" The liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The driving method of the liquid crystal in the liquid crystal element is not particularly limited. For example, it can be applied to the twisted nematic (TN) type, the super twisted nematic (Super Twisted Nematic, STN) type, and the vertical alignment (Vertical Alignment, VA) type. (Including Vertical Alignment-Multi-domain Vertical Alignment (VA-MVA) type, Vertical Alignment-Patterned Vertical Alignment (VA-PVA) type, etc.), coplanar switching (In-Plane Switching, IPS) type, Fringe Field Switching (FFS) type, Optically Compensated Bend (OCB) type, Polymer Sustained Alignment (PSA) type and other modes. The liquid crystal element can be manufactured, for example, by a method including the coating film forming step and the photo-alignment treatment step, and the following cell construction step.

The substrate used in the coating film formation step differs depending on the desired operation mode. For example, when manufacturing a TN-type, STN-type, or VA-type liquid crystal element, two substrates on which patterned transparent conductive films are provided are used. When manufacturing an IPS type or FFS type liquid crystal element, a substrate provided with electrodes patterned into a comb-tooth shape and a counter substrate provided with no electrodes are used. As the transparent conductive film, NESA film (registered trademark of PPG Corporation of the United States) containing tin oxide (SnO ₂ ), indium tin oxide (Indium oxide) containing tin oxide (In ₂ O ₃ -SnO ₂ ) can be used. Tin Oxide, ITO) film, etc.

·Unit construction steps In the unit construction step, two substrates on which liquid crystal alignment films are formed through the photo-alignment treatment step are prepared, and liquid crystal is arranged between the two facing substrates to manufacture a liquid crystal cell. When manufacturing a liquid crystal cell, for example, the following method can be used: arranging two substrates facing each other through a gap so that the liquid crystal alignment films face each other, bonding the peripheral portions of the two substrates with a sealant, and sealing the substrate surface with the sealant. The method of injecting filling liquid crystal into the surrounding cell gap and sealing the injection hole, and the method of using liquid crystal dripping (One Drop Fill, ODF) method. As the sealant, for example, epoxy resin containing a hardener and alumina balls as spacers can be used.

As the liquid crystal, either positive type or negative type can be used. When a negative liquid crystal is used in an IPS type or FFS type liquid crystal element, the transmission loss in the upper part of the electrode can be reduced and the contrast can be improved, which is preferable in this regard. In addition, in a photodecomposable liquid crystal alignment film that develops anisotropy through decomposition of the polymer due to light irradiation, thus imparting liquid crystal alignment ability to the film, when a negative-type liquid crystal is used to produce a liquid crystal element , there is a tendency for a high occurrence rate of display defects (bright spots) caused by decomposition products of polymers produced by radiation irradiation. In contrast, with the liquid crystal alignment agent of the present disclosure, a high-quality liquid crystal element in which the generation of bright spots is suppressed can be obtained. Examples of the liquid crystal include nematic liquid crystal and smectic liquid crystal. Among them, nematic liquid crystal is preferred.

When manufacturing a liquid crystal display device, a polarizing plate is then bonded to the outer surface of the liquid crystal cell. Examples of polarizing plates include those in which a polarizing film called an "H film" in which polyvinyl alcohol is stretched and oriented while absorbing iodine is sandwiched between cellulose acetate protective films, or a polarizing plate containing H The film itself is a polarizer.

The liquid crystal element of the present disclosure can be effectively applied to various uses. Specifically, it can be used as a clock, a portable game, a word processor, a notebook personal computer, a car navigation system, a camcorder, or a personal digital assistant. (Personal Digital Assistant, PDA), digital cameras, mobile phones, smart phones, various monitors, LCD TVs, information displays and other display devices or dimming devices, phase difference films, etc.

The present disclosure described above can provide the following means.

[Mean 1] A method for manufacturing a liquid crystal alignment film, including the steps of forming a coating film using a liquid crystal alignment agent containing a polymer [A] having the partial structure (a) represented by the formula (1); and The coating film is subjected to a step of irradiating light to impart alignment ability to the liquid crystal. [Mean 2] The method for manufacturing a liquid crystal alignment film according to [Mean 1], wherein the polymer [A] has a structural unit derived from the compound represented by the formula (2). [Method 3] The method for manufacturing a liquid crystal alignment film according to [Method 1] or [Method 2], wherein the polymer [A] is selected from the group consisting of polyamic acid, polyamic acid ester and polyimide. at least one of the groups formed. [Mean 4] The method for manufacturing a liquid crystal alignment film according to any one of [Mean 1] to [Mean 3], wherein the polymer [A] has a structural unit derived from an aliphatic tetracarboxylic dianhydride. [Mean 5] The method for manufacturing a liquid crystal alignment film according to [Mean 4], wherein the aliphatic tetracarboxylic dianhydride has a partial structure represented by the formula (4). [Mean 6] The method for manufacturing a liquid crystal alignment film according to any one of [Mean 1] to [Mean 5], further containing a polymer [B] that does not have the partial structure (a). [Method 7] The method for manufacturing a liquid crystal alignment film according to [Method 6], wherein the polymer [B] is selected from the group consisting of polyamide acid, polyamide ester, and polyimide. at least one of them. [Mean 8] A photoalignment agent containing a polymer [A] having the partial structure (a) represented by the formula (1). [Mean 9] A liquid crystal element including a liquid crystal alignment film manufactured by the method according to any one of [Mean 1] to [Mean 7]. [Mean 10] A polymer containing a structural unit derived from the diamine represented by the formula (3). [Mean 11] A diamine represented by the above formula (3). [Example]

Hereinafter, embodiments will be described in more detail based on examples. However, the present invention is not limitedly interpreted by the following examples.

In the following examples, the imidization rate of the polyimide in the polymer solution was measured by the following method. [Imination rate of polyimide] The solution of polyimide is put into pure water, and the obtained precipitate is fully dried under reduced pressure at room temperature, and then dissolved in deuterated dimethyl sulfoxide. Using tetramethylsilane as a reference material, ¹ H-nuclear magnetic resonance (NMR) measurement was performed at room temperature. From the obtained ¹ H-NMR spectrum, the acyl imidization rate [%] was determined by the following mathematical formula (I). Imination rate [%] = (1-(A ¹ / (A ² × α))) × 100 ··· (I) (In formula (I), A ¹ appears near the chemical shift of 10 ppm The peak area of protons originating from the NH group, A ² is the peak area originating from other protons, α is the ratio of the number of other protons to one proton of the NH group in the precursor of the polymer (polyamide) )

The abbreviations of the compounds are as follows. In addition, the compound represented by formula (X) (X is a symbol) may be simply expressed as "compound (X)" below.

(Tetracarboxylic dianhydride) [Chemical 15]

(Diamine compound) [Chemical 16] [Chemical 17]

<Synthesis of Monomer> [Synthesis Example 1A] Compound (DA-1) was synthesized according to the following scheme. [Chemical 18]

Put 4-nitroguaiacol (23.72 g), 1,2-bis(toluenesulfonyloxy)ethane (25.34 g), and potassium carbonate ( 23.63 g) and perform nitrogen replacement. 130 mL of dimethylformamide was added thereto, and the temperature was gradually raised to 80°C and stirred for 6 hours. After the reaction, 650 mL of pure water was added to the reaction solution and stirred for 1 hour. The precipitated crystals were filtered under reduced pressure, and the crude product was washed with water and 2-propanol and dried under vacuum to obtain a powdery dinitroform intermediate product (23.25 g, yield 93%). Then, a three-necked flask including a reflux tube and a nitrogen gas introduction tube was placed in the dinitrobase intermediate product (23.25 g) and 408 mg of palladium on carbon, and the flask was replaced with nitrogen. 65 mL of tetrahydrofuran and 65 mL of ethanol degassed by nitrogen bubbling were added thereto, and the mixture was stirred while cooling to 5°C to prepare a suspension solution. Slowly add 18.5 mL of hydrazine monohydrate dropwise to the suspended solution. After the dropwise addition, the temperature was slowly raised to 60°C and stirred for 4 hours. The reaction solution was diluted by adding tetrahydrofuran, filtered through diatomaceous earth, and then concentrated to precipitate the product. The obtained precipitate was washed with tetrahydrofuran (THF), and the crystals were filtered under reduced pressure. The obtained crystals were washed with water and 2-propanol and dried in vacuum to obtain compound (DA-1) as a yellowish-orange solid (16.04 g, yield 79%). Its structure is confirmed by ¹ H-NMR spectrum, which is a nuclear magnetic resonance spectrum of hydrogen atoms in the molecule. The measurement data are shown below. ¹ H-NMR (400 MHz, [D ₆ ]-DMSO) δ: 6.67 (dd, 2H), 6.26 (d, 2H), 6.04 (dd, 2H), 4.70 (s, 4H), 4.01 (s, 4H ), 3.66 (s, 6H).

＜Synthesis of polymer＞ 1.Synthesis of polyamide [Synthesis example 1] 100 mole parts of compound (TA-1) as tetracarboxylic dianhydride, 40 mole parts of compound (DA-1) as diamine compound, 40 mole parts of compound (DB-5) and compound (DB- 8) Dissolve 20 mole parts in N-methyl-2-pyrrolidone (NMP) and react at room temperature for 6 hours to obtain a polyamic acid containing 15 mass% It is set as a solution of polymer (PA-1)).

[Synthesis Example 2 to Synthesis Example 9] Except that the types and amounts of the tetracarboxylic dianhydride and diamine compound used were changed as described in Tables 1 and 2, the same operation as in Synthesis Example 1 was performed to obtain a polyamide containing 15% by mass ( Solution of polymer (PA-2) ~ polymer (PA-9)).

[Table 1] Polymer name Acid dianhydride 1 Diamine 1 Diamine 2 Diamine 3 Kind Morby Kind Morby Kind Morby Kind Morby Synthesis example 1 PA-1 TA-1 100 DA-1 40 DB-5 40 DB-8 20 Synthesis example 2 PA-2 TA-1 100 DA-2 70 DB-3 20 DB-6 10

[Table 2] Polymer name Acid dianhydride 1 Acid dianhydride 2 Diamine 1 Diamine 2 Kind Morby Kind Morby Kind Morby Kind Morby Synthesis example 3 PA-3 TA-2 10 TA-6 90 DB-8 80 DB-11 20 Synthesis example 4 PA-4 TA-2 30 TA-1 70 DB-1 50 DB-12 50 Synthesis example 5 PA-5 TA-1 70 TA-3 30 DB-2 30 DB-13 70 Synthesis example 6 PA-6 TA-2 20 TA-3 80 DB-6 60 DB-14 40 Synthesis Example 7 PA-7 TA-2 70 TA-4 30 DB-9 80 DB-10 20 Synthesis example 8 PA-8 TA-2 100 DB-8 50 DB-15 50 Synthesis example 9 PA-9 TA-2 70 TA-5 30 DB-6 100

2. Synthesis of polyimide [Synthesis Example 10] Dissolve 90 mole parts of compound (TA-1) as a tetracarboxylic dianhydride, 10 mole parts of a compound (TA-2), and 100 mole parts of a compound (DA-1) as a diamine compound in N-methyl In 2-pyrrolidone (NMP), the reaction was carried out at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamic acid. Next, NMP was added to the obtained polyamic acid solution to prepare a solution with a polyamic acid concentration of 10% by mass, pyridine and acetic anhydride were added, and a dehydration ring-closure reaction was performed at 60° C. for 4 hours. After the dehydration and ring-closure reaction, new NMP was used to replace the solvent in the system, thereby obtaining a polyimide containing 15% by mass and a polyimide rate of approximately 90% (referred to as a polymer (PI -1)) solution.

[Synthesis Example 11 to Synthesis Example 20] The types and amounts of the tetracarboxylic dianhydride and diamine compound used were changed as described in Table 3, and the amounts of pyridine and acetic anhydride were adjusted so that the acyl imidization rate was synthesized as described in Table 3. , thereby obtaining a solution containing 15% by mass of polyimide (polymer (PI-2) to polymer (PI-11)).

[table 3] Polymer name Acid dianhydride 1 Acid dianhydride 2 Diamine 1 Diamine 2 Diamine 3 acyl imidization rate Kind Morby Kind Morby Kind Morby Kind Morby Kind Morby Synthesis example 10 PI-1 TA-1 90 TA-2 10 DA-1 100 90% Synthesis Example 11 PI-2 TA-1 100 DA-1 50 DB-3 20 DB-10 30 80% Synthesis example 12 PI-3 TA-1 70 TA-5 30 DA-2 100 40% Synthesis example 13 PI-4 TA-1 80 TA-6 20 DA-2 50 DB-5 50 50% Synthesis Example 14 PI-5 TA-1 100 DA-3 60 DB-1 20 DB-4 20 60% Synthesis Example 15 PI-6 TA-1 100 DA-4 30 DB-7 50 DB-8 20 30% Synthesis Example 16 PI-7 TA-1 80 TA-3 20 DA-5 40 DB-5 40 DB-9 20 80% Synthesis Example 17 PI-8 TA-1 100 DA-6 70 DB-9 30 80% Synthesis example 18 PI-9 TA-1 100 DA-7 60 DB-3 40 70% Synthesis example 19 PI-10 TA-1 100 DA-8 30 DB-10 70 50% Synthesis example 20 PI-11 TA-1 100 DA-1 50 DB-10 30 DB-16 20 85%

＜Preparation and evaluation of liquid crystal alignment agent＞ [Example 1] 1. Preparation of liquid crystal alignment agent The solution of the polymer (PA-1) obtained in Synthesis Example 1 and the solution of the polymer (PA-3) obtained in Synthesis Example 3 were divided into polymer (PA-1) and polymer (PA-3) in a solid form. The ingredients are mixed so that (PA-1)/(PA-3)=30/70 (mass ratio), diluted with NMP and butyl cellosolve (BC), and the solvent composition is NMP/BC= A solution of 80/20 (mass ratio) and solid content concentration of 3.5 mass%. The solution was filtered using a screening program with a pore size of 0.2 μm, thereby preparing a liquid crystal alignment agent (AL-1).

2. Manufacturing of FFS-type liquid crystal display elements using the photoalignment method. Prepare a glass substrate (referred to as the first substrate) in which a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) are laminated on one side in order. , and a glass substrate without electrodes (set as the second substrate). Then, the liquid crystal alignment agent (AL-1) was applied to the electrode formation surface of the first substrate and one surface of the second substrate respectively using a rotator, and heated (pre-baked) using a hot plate at 80°C for 1 minute. Then, drying (post-baking) was performed for 30 minutes in a 150°C oven that replaced nitrogen in the chamber to form a coating film with an average film thickness of 0.1 μm. The obtained coating film was irradiated with 1,000 J/m ² of ultraviolet light containing a linearly polarized bright line of 254 nm from the normal direction of the substrate using an Hg-Xe lamp to perform photo-alignment treatment. In addition, the irradiation amount is a value measured using a light meter based on a wavelength of 254 nm. Then, the coating film that has been subjected to the photo-alignment treatment is heated in a clean oven at 150° C. for 30 minutes to perform heat treatment to form a liquid crystal alignment film. Next, for one of the pair of substrates on which the liquid crystal alignment film is formed, an epoxy resin adhesive containing alumina balls with a diameter of 3.5 μm is applied to the outer edge of the surface with the liquid crystal alignment film by screen printing. . Then, the substrates were overlapped and pressure-bonded so that the projection direction of the polarization axis on the substrate surface during light irradiation became antiparallel, and the adhesive was thermally cured at 150° C. for 1 hour. Next, a negative liquid crystal (MLC-6608 manufactured by Merck) was filled from the liquid crystal injection port into the space between the pair of substrates, and then the liquid crystal injection port was sealed with an epoxy-based adhesive to obtain a liquid crystal cell. Furthermore, in order to remove the flow alignment during liquid crystal injection, it was heated at 120° C. and then slowly cooled to room temperature. Then, the polarizing plate is bonded to both outer surfaces of the substrate in the liquid crystal cell to obtain a liquid crystal display element. In addition, by changing the ultraviolet irradiation amount after post-baking in the range of 100 J/m ² to 10,000 J/m ² and performing the above-mentioned series of operations, three or more ultraviolet irradiation dosages with different ultraviolet irradiation amounts are manufactured. As for the liquid crystal display element, the liquid crystal display element with the exposure amount (optimum exposure amount) showing the best alignment characteristics was used for the following evaluation.

3. Evaluation of liquid crystal alignment. The liquid crystal display element manufactured in the above 2. was left to stand on a high-brightness backlight of 27,000 cd/m ² for 500 hours, and the liquid crystal alignment was evaluated based on the change rate α of the retardation before and after irradiation of the backlight. . The retardation was measured using an Axoscan manufactured by Opto Science, and the change rate α of the retardation before and after backlight irradiation was calculated using the following equation (II). It can be said that the smaller the change rate α is, the better the liquid crystal alignment is. When the change rate α is 0.5% or less, it is regarded as "excellent (◎)", when it is more than 0.5% and less than 1%, it is "good (○)", when it is more than 1% and less than 2%, it is regarded as "good (○)" Set it to "Acceptable (△)", and set it to "Defect (×)" if it exceeds 2%. α=Δθ/θ1 ···(II) (In formula (II), Δθ represents the retardation difference before and after irradiation, and θ1 represents the retardation value before irradiation) As a result, the liquid crystal alignment property of the above example was "good (○ )" evaluation.

4. Evaluation of bright spots (bright spot suppression properties) of liquid crystal cells The liquid crystal cell manufactured in 2. above was observed using a polarizing microscope (ECLIPSE E600WPOL) (manufactured by Nikon Corporation), and the bright spot suppression property was evaluated. Specifically, a liquid crystal cell was placed between two polarizing plates arranged so that the polarization axes were orthogonal to each other, and the liquid crystal cell was observed using a polarizing microscope with a magnification of 5 times (observation area: approximately 2500 μm × 2500 μm). . It can be said that the smaller the number of bright spots, the better the decomposition products produced by the photoalignment process will be. When the number of bright spots is 100 or more, it is classified as "poor (×)"; when it is 10 or more and less than 100, it is classified as "acceptable (△)"; when it is less than 10, it is classified as "good (○)" )". The result was "good (○)" in the above Example.

5. Evaluation of key durability based on key test For the liquid crystal display element manufactured in the above 2., the liquid crystal alignment property after performing the key test was evaluated. Evaluation is performed as follows. A silicone rubber pen 3R (manufactured by Touch Panel Laboratory Co., Ltd.) with a tip shape of 3 mm is installed on the key section (solenoid type) of the key testing machine (Touch Panel Laboratory Co., Ltd.), and the pen tip is Set to be located at the center of the liquid crystal display element. After using a silicone rubber pen to press the keys 10,000 times under a load of 500 g and 10 Hz, the liquid crystal display element was observed using a microscope (100 times) and the number of bright spots was measured. It can be said that the smaller the number of bright points, the more excellent the key durability of the liquid crystal display element is. The number of bright spots is judged as "Excellent (◎)" when the number of bright spots is less than 30, the number of bright spots is judged as "Good (○)" when it is between 30 and less than 50, and the number of bright spots is judged as "Acceptable (○)" when it is between 50 and less than 100. (△)", and cases with more than 100 are judged as "Defect (×)". The result was an evaluation of "good (○)" in the Examples.

6. Evaluation of adhesion: Use a spinner to apply the liquid crystal alignment agent (AL-1) prepared in step 1. on the glass substrate, pre-bakes it with a hot plate at 80°C for 2 minutes, and then perform the test in the warehouse. Heating (post-baking) for 30 minutes in a 230°C oven with nitrogen replacement formed a coating film with an average film thickness of 0.10 μm. By repeating the same operation as this, two glass substrates on which the coating film is formed are produced. On the coating film of one glass substrate on which the coating film is formed, ODF sealant (S-WB42 manufactured by Sekisui Chemical Co., Ltd.) is applied to a width of 1 mm, and the coating film of the other glass substrate is in contact with the ODF sealant. way to fit. Then, a metal halide lamp was used to irradiate light of 30,000 J/m ² (converted to 365 nm), and then heated in an oven at 120° C. for 1 hour. Then, the adhesive force of the film was measured using a tensile compression testing machine (Imada Seisakusho Co., Ltd. model: SDWS-0201-100SL) to evaluate the adhesiveness of the film. Regarding evaluation, the case where the adhesion force is 175 N/cm ² or more is regarded as "good (○)", the case where the adhesion force is 125 N/cm ² or more and less than 175 N/cm ² is regarded as "acceptable (△)", If it is less than 125 N/cm ² , it is classified as "defective (×)". As a result, in the above example, the adhesion force was 175 N/cm ² , and the adhesion was evaluated as “good (○)”.

[Example 2 to Example 12 and Comparative Example 1 to Comparative Example 3] A liquid crystal alignment agent was prepared in the same manner as in Example 1, except that the composition of the liquid crystal alignment agent was changed as shown in Table 4. In addition, using the obtained liquid crystal alignment agent, an FFS type liquid crystal display element was manufactured by the photoalignment method in the same manner as in Example 1, and the liquid crystal alignment properties, bright spot suppression properties, key durability and adhesiveness were evaluated. These results are shown in Table 4. In addition, in Examples 2, 4, 6, 8 to 10, 12, and Comparative Examples 2 and 3, two types of polymers were used as polymer components. 5. In Example 7 and Example 11, three types of polymers were used as polymer components. In Table 4, the numerical value in the polymer column represents the compounding ratio (parts by mass) of each polymer in terms of solid content relative to 100 parts by mass of the total amount of polymer components used in the preparation of the liquid crystal alignment agent.

[Table 4] Alignment agent composition Characteristic evaluation Polymer 1 Polymer 2 Polymer 3 Liquid crystal alignment Highlights of LCD Units Button test Tightness Kind mass ratio Kind mass ratio Kind mass ratio Example 1 PA-1 30 PA-3 70 ○ ○ ○ ○ Example 2 PA-2 50 PA-4 50 ○ ○ ◎ ○ Example 3 PI-1 100 ◎ ○ ○ ○ Example 4 PI-1 20 PA-5 80 ◎ ○ ○ ○ Example 5 PI-2 30 PA-6 30 PA-8 40 ◎ ○ ○ ○ Example 6 PI-2 40 PA-3 60 ◎ ○ ○ ○ Example 7 PI-3 10 PA-5 30 PA-7 60 ○ ○ ◎ ○ Example 8 PI-4 10 PA-6 90 ○ ○ ◎ ○ Example 9 PI-5 10 PA-7 90 △ ○ ○ ○ Example 10 PI-6 30 PA-8 70 ○ ○ ○ ○ Example 11 PI-7 30 PA-4 30 PA-9 40 △ ○ ○ ○ Example 12 PI-11 40 PA-3 60 ◎ ○ ○ ○ Comparative example 1 PI-8 100 △ × × × Comparative example 2 PI-9 20 PA-6 80 △ ○ × △ Comparative example 3 PI-10 30 PA-5 70 × ○ ○ ○

As shown in Table 4, compared with Examples 1 to 12 using a liquid crystal alignment agent containing polymer [A] and Comparative Examples 1 to 3 using a liquid crystal alignment agent not containing polymer [A], the following results were obtained: It achieves a good balance between liquid crystal alignment, bright spot suppression of liquid crystal cells, button durability and film adhesion.

From the above results, it is clear that a liquid crystal element that is excellent in liquid crystal alignment, key durability, and adhesion and has few bright spots in the liquid crystal cell can be obtained by using a liquid crystal alignment agent containing polymer [A].

Claims (11)

A method for manufacturing a liquid crystal alignment film, comprising: forming a coating film using a liquid crystal alignment agent containing a polymer [A] having a partial structure (a) represented by the following formula (1); and treating the coating film The step of irradiating light to impart alignment ability to liquid crystal, In formula (1), A ¹ and A ² are each independently a divalent aromatic ring group; wherein, one or both of A ¹ and A ² have -OR ¹ , -NR ² R ³ or -SR ⁴ The structure represented by the group is bonded to an aromatic ring; R ¹ , R ² and R ⁴ are each independently a hydrogen atom or a monovalent organic group; R ³ is a monovalent organic group; B ¹ and B ² are each independently Single bond, -O-, -S-, -NR ⁵ -, -CO-, * ¹ -CO-O-, * ¹ -O-CO-, * ¹ -CS-O-, * ¹ -O-CS -, * ¹ -CO-NR ⁶ - or * ¹ -NR ⁶ -CO-NR ⁷ -; "* ¹ " represents the bond with A ¹ or A ² ; R ⁵ , R ⁶ and R ⁷ are independently is a hydrogen atom or a monovalent organic group; X is a divalent hydrocarbon group; "*" represents a bond. The method for manufacturing a liquid crystal alignment film according to claim 1, wherein the polymer [A] has a structural unit derived from a compound represented by the following formula (2); In the formula (2), A ¹ , A ² , B ¹ , B ² and X have the same meaning as in the above formula (1). The method of manufacturing a liquid crystal alignment film according to claim 1, wherein the polymer [A] is at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide. The method for manufacturing a liquid crystal alignment film according to claim 3, wherein the polymer [A] has a structural unit derived from an aliphatic tetracarboxylic dianhydride. The method for manufacturing a liquid crystal alignment film according to claim 4, wherein the aliphatic tetracarboxylic dianhydride has a partial structure represented by the following formula (4); In formula (4), R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are each independently a hydrogen atom or a substituent; wherein, more than one of R ¹¹ , R ¹² , R ¹³ and R ¹⁴ is a substituent; "* ” means bonding the key. The method for manufacturing a liquid crystal alignment film according to claim 1 further contains a polymer [B] that does not have the partial structure (a). The method for manufacturing a liquid crystal alignment film according to claim 6, wherein the polymer [B] is at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide. A photoalignment agent containing a polymer [A] having partial structure (a) represented by the following formula (1); In formula (1), A ¹ and A ² are each independently a divalent aromatic ring group; wherein, one or both of A ¹ and A ² have -OR ¹ , -NR ² R ³ or -SR ⁴ The structure represented by the group is bonded to an aromatic ring; R ¹ , R ² and R ⁴ are each independently a hydrogen atom or a monovalent organic group; R ³ is a monovalent organic group; B ¹ and B ² are each independently Single bond, -O-, -S-, -NR ⁵ -, -CO-, * ¹ -CO-O-, * ¹ -O-CO-, * ¹ -CS-O-, * ¹ -O-CS -, * ¹ -CO-NR ⁶ - or * ¹ -NR ⁶ -CO-NR ⁷ -; "* ¹ " represents the bond with A ¹ or A ² ; R ⁵ , R ⁶ and R ⁷ are independently is a hydrogen atom or a monovalent organic group; X is a divalent hydrocarbon group; "*" represents a bond. A liquid crystal element including a liquid crystal alignment film manufactured by the method according to any one of claims 1 to 7. A polymer containing a structural unit derived from a diamine represented by the following formula (3); In formula (3), A ³ and A ⁴ are each independently a divalent aromatic ring group; wherein, one or both of A ³ and A ⁴ have a base bond represented by -OR ^1a or -NR ^2a R ^3a A structure formed by an aromatic ring; R ^1a and R ^2a are each independently a monovalent hydrocarbon group; R ^3a is a hydrogen atom or a monovalent organic group; B ³ and B ⁴ are each independently a single bond, -O-, - S-, -NR ^5a -, -CO-, * ¹ -CO-O-, * ¹ -O-CO-, * ¹ -CS-O-, * ¹ -O-CS-, * ¹ -CO-NR ^6a - or * ¹ -NR ^6a -CO-NR ^7a -; R ^5a is a monovalent organic group; R ^6a and R ^7a are independently a hydrogen atom or a monovalent organic group; "* ¹ " means the same as A ³ or A ⁴ bond; when B ³ is -O-, Y is an alkanediyl group with 1 or 2 carbon atoms, a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group, and when B ³ is * ¹ -O In the case of -CO-, Y is an alkanediyl group, a divalent alicyclic hydrocarbon group having an aliphatic hydrocarbon ring having 4 or more carbon atoms, or a divalent aromatic hydrocarbon group, and B ³ is -O- and * ¹ -O- In the case other than CO-, Y is a divalent hydrocarbon group. A diamine represented by the following formula (3); In formula (3), A ³ and A ⁴ are each independently a divalent aromatic ring group; wherein, one or both of A ³ and A ⁴ have a base bond represented by -OR ^1a or -NR ^2a R ^3a A structure formed by an aromatic ring; R ^1a and R ^2a are each independently a monovalent hydrocarbon group; R ^3a is a hydrogen atom or a monovalent organic group; B ³ and B ⁴ are each independently a single bond, -O-, - S-, -NR ^5a -, -CO-, * ¹ -CO-O-, * ¹ -O-CO-, * ¹ -CS-O-, * ¹ -O-CS-, * ¹ -CO-NR ^6a - or * ¹ -NR ^6a -CO-NR ^7a -; R ^5a is a monovalent organic group; R ^6a and R ^7a are independently a hydrogen atom or a monovalent organic group; "* ¹ " means the same as A ³ or A ⁴ bond; when B ³ is -O-, Y is an alkanediyl group with 1 or 2 carbon atoms, a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group, and when B ³ is * ¹ -O In the case of -CO-, Y is an alkanediyl group, a divalent alicyclic hydrocarbon group having an aliphatic hydrocarbon ring having 4 or more carbon atoms, or a divalent aromatic hydrocarbon group, and B ³ is -O- and * ¹ -O- In the case other than CO-, Y is a divalent hydrocarbon group.