JP7322894B2 - Liquid crystal aligning agent and its manufacturing method, liquid crystal aligning film and liquid crystal element - Google Patents

Description

Cross-reference to related applications

This application is based on Japanese Patent Application No. 2018-210851 filed on November 8, 2018, and the description thereof is incorporated herein.

TECHNICAL FIELD The present disclosure relates to a liquid crystal aligning agent, a method for producing the same, a liquid crystal aligning film, and a liquid crystal element.

Liquid crystal elements include horizontal alignment mode liquid crystal elements using nematic liquid crystals having positive dielectric anisotropy, typified by TN (Twisted Nematic) type and STN (Super Twisted Nematic) type, and liquid crystal elements with negative dielectric anisotropy. 2. Description of the Related Art Various liquid crystal elements are known, such as a homeotropic alignment mode VA (Vertical Alignment) type liquid crystal element using a nematic liquid crystal having properties. These liquid crystal elements are provided with a liquid crystal alignment film having a function of aligning liquid crystal molecules in a certain direction.

In general, a liquid crystal alignment film is formed by coating a substrate with a liquid crystal alignment agent obtained by dissolving a polymer component in an organic solvent and heating the substrate. As the polymer component of the liquid crystal aligning agent, polyamic acid and soluble polyimide are generally used because they are excellent in mechanical strength, liquid crystal alignment, and affinity with liquid crystals. In addition, as the polymer component of the liquid crystal aligning agent, it has been proposed to use a polymer different from polyamic acid or polyimide, such as a maleimide polymer, a maleimide-styrene polymer, a maleic acid amide polymer, or a maleic acid polymer. (See Patent Documents 1 to 3, for example).

As the solvent component of the liquid crystal aligning agent, a high boiling point solvent such as N-methyl-2-pyrrolidone (NMP), which is an aprotic polar solvent, is generally used. In addition, by using an organic solvent having a low surface tension such as butyl cellosolve (BC) in combination with a high boiling point solvent such as NMP, the coating property (printability) of the liquid crystal aligning agent on the substrate is improved. .

Japanese Patent No. 2962473 Japanese Patent No. 3612308 WO2018/074548

When the liquid crystal aligning agent is applied to the substrate, if the liquid crystal aligning agent has low wettability and spreadability, the liquid crystal aligning film tends to have uneven coating (uneven film thickness) and pinholes, and it may not be possible to form a uniform film. be. In such a case, we are anxious about the performance of a liquid crystal aligning film falling.

In recent years, the demand for display quality of liquid crystal elements has become more severe. In a liquid crystal element, if the relaxation rate of accumulated charges with respect to the application of a DC voltage is slow or the amount of accumulated charges is large, an afterimage will be induced, and there is a concern that the display quality of the liquid crystal element will be deteriorated. Therefore, the liquid crystal alignment film is required to be difficult to accumulate electric charge (lower amount of accumulated residual electric charge).

The present disclosure has been made in view of the above circumstances, and one object thereof is to provide a liquid crystal element that can obtain a liquid crystal aligning agent that exhibits good applicability to a substrate and has a small amount of accumulated residual charge. It is to provide a liquid crystal aligning agent that can be obtained.

The present inventors have made intensive studies to solve the above problems, found that the above problems can be solved by combining a polymer having a specific structure and a specific solvent to prepare a liquid crystal aligning agent, and completed the present disclosure. I came to do it. According to the present disclosure, the following means are provided.
[1] Selected from the group consisting of a polymer (P) having a partial structure represented by the following formula (A) and a compound represented by each of the following formulas (E-1) to (E-5) A liquid crystal aligning agent containing at least one organic solvent having a boiling point of 190° C. or lower at 1 atm.

（式（Ａ）中、「＊」は結合手を示す。）

（式（Ｅ－１）中、Ｒ^４１は、炭素数１～３のアルキル基又はＲ^４０－ＣＯ－（ただし、Ｒ^４０は炭素数１～３のアルキル基）であり、Ｒ^４２は、炭素数１～４のアルカンジイル基又は－（Ｒ^４７－Ｏ）ｒ－Ｒ^４８－（ただし、Ｒ^４７及びＲ^４８は、それぞれ独立に炭素数２又は３のアルカンジイル基であり、ｒは１～４の整数である。）であり、Ｒ^４３は、水素原子又は炭素数１～３のアルキル基である。）

（式（Ｅ－２）中、Ｒ^４４は、炭素数１～４のアルカンジイル基である。）

（式（Ｅ－３）中、Ｒ^４５及びＲ^４６は、それぞれ独立に炭素数１～８のアルキル基である。）

（式（Ｅ－４）中、Ｒ^４９は、水素原子又は水酸基であり、Ｒ^５０は、Ｒ^４９が水素原子の場合、炭素数１～９の２価の炭化水素基、又は炭素数３～９の鎖状炭化水素基の炭素－炭素結合間に－ＣＯ－を有する２価の基であり、Ｒ^４９が水酸基の場合、炭素数１～９の２価の炭化水素基、又は炭素数２～９の炭化水素基の炭素－炭素結合間に酸素原子を有する２価の基である。）

（式（Ｅ－５）中、Ｒ^５１は、炭素数１～６の１価の炭化水素基、炭素数１～６の炭化水素基が有する水素原子が水酸基で置換された１価の基、又は炭素数２～６の炭化水素基の炭素－炭素結合間に－ＣＯ－を有する１価の基であり、Ｒ^５２は、炭素数１～６の１価の炭化水素基である。）
［２］上記［１］の液晶配向剤を用いて形成された液晶配向膜。
［３］上記［２］の液晶配向膜を具備する液晶素子。
［４］液晶配向剤の製造方法であって、重合体成分と有機溶剤とを混合する工程を含み、前記重合体成分は、上記式（Ａ）で表される部分構造を有する重合体（Ｐ）、及び前記重合体（Ｐ）と下記式（４）で表される化合物とを反応させて得られる重合体よりなる群から選ばれる少なくとも一種を含み、前記有機溶剤は、上記式（Ｅ－１）～式（Ｅ－５）のそれぞれで表される化合物よりなる群から選ばれる少なくとも一種であって、かつ１気圧での沸点が１９０℃以下である化合物を含有する、液晶配向剤の製造方法。

（式（４）中、Ｒ^１０は、炭素数１以上の１価の有機基であり、Ｘ^１は酸素原子又は－ＮＲ^１１－（Ｒ^１１は水素原子又は炭素数１～５の１価の炭化水素基である。）である。）

(In formula (A), "*" indicates a bond.)

(In formula (E-1), R ⁴¹ is an alkyl group having 1 to 3 carbon atoms or R ⁴⁰ —CO— (wherein R ⁴⁰ is an alkyl group having 1 to 3 carbon atoms), and R ⁴² is a carbon an alkanediyl group having a number of 1 to 4 or —(R ⁴⁷ —O)r—R ⁴⁸ — (provided that R ⁴⁷ and R ⁴⁸ are each independently an alkanediyl group having 2 or 3 carbon atoms and r is 1 to is an integer of 4), and R ⁴³ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

(In formula (E-2), R ⁴⁴ is an alkanediyl group having 1 to 4 carbon atoms.)

(In formula (E-3), R ⁴⁵ and R ⁴⁶ are each independently an alkyl group having 1 to 8 carbon atoms.)

(In formula (E-4), R ⁴⁹ is a hydrogen atom or a hydroxyl group, and R ⁵⁰ is a divalent hydrocarbon group having 1 to 9 carbon atoms or 3 to 3 carbon atoms when R ⁴⁹ is a hydrogen atom. A chain hydrocarbon group of 9 - a divalent group having -CO- between the carbon bonds, and when R ⁴⁹ is a hydroxyl group, a divalent hydrocarbon group having 1 to 9 carbon atoms, or 2 carbon atoms It is a divalent group having an oxygen atom between the carbon-carbon bonds of the hydrocarbon groups of 1 to 9.)

(In the formula (E-5), R ⁵¹ is a monovalent hydrocarbon group having 1 to 6 carbon atoms, a monovalent group in which the hydrogen atom of the hydrocarbon group having 1 to 6 carbon atoms is substituted with a hydroxyl group, or a monovalent group having —CO— between the carbon-carbon bonds of a hydrocarbon group having 2 to 6 carbon atoms, and R ⁵² is a monovalent hydrocarbon group having 1 to 6 carbon atoms.)
[2] A liquid crystal alignment film formed using the liquid crystal alignment agent of [1] above.
[3] A liquid crystal device comprising the liquid crystal alignment film of [2] above.
[4] A method for producing a liquid crystal aligning agent, comprising a step of mixing a polymer component and an organic solvent, wherein the polymer component is a polymer (P ), and at least one selected from the group consisting of polymers obtained by reacting the polymer (P) with a compound represented by the following formula (4), and the organic solvent is the above formula (E- 1) Production of a liquid crystal aligning agent containing at least one compound selected from the group consisting of compounds represented by each of formulas (E-5) and having a boiling point of 190° C. or lower at 1 atm. Method.

(In formula (4), R ¹⁰ is a monovalent organic group having 1 or more carbon atoms, X ¹ is an oxygen atom or —NR ¹¹ — (R ¹¹ is a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms). It is a hydrocarbon group.)

According to the liquid crystal aligning agent containing the above polymer (P) and the above organic solvent, it is possible to obtain a liquid crystal aligning agent that exhibits good applicability to a substrate, and a liquid crystal that accumulates a small amount of residual charge. element can be obtained.

≪Liquid crystal aligning agent≫
The liquid crystal aligning agent of this indication contains a polymer (P) and a solvent component. This liquid crystal aligning agent is prepared as a polymer composition in which a polymer component containing the polymer (P) is dissolved in a solvent. Below, each component contained in a liquid crystal aligning agent and the other component mix|blended arbitrarily as needed are demonstrated.

As used herein, the term "hydrocarbon group" includes a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group. A "chain hydrocarbon group" means a straight chain hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure in its main chain and is composed only of a chain structure. However, it may be saturated or unsaturated. The “alicyclic hydrocarbon group” means a hydrocarbon group containing only an alicyclic hydrocarbon structure as a ring structure and not containing an aromatic ring structure. However, it does not have to be composed only of an alicyclic hydrocarbon structure, and includes those having a chain structure in part thereof. An "aromatic hydrocarbon group" means a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it does not have to be composed only of an aromatic ring structure, and may partially contain a chain structure or an alicyclic hydrocarbon structure.

<Polymer (P)>
The polymer (P) has a partial structure represented by the above formula (A) (hereinafter also referred to as “specific partial structure”) in at least one of its main chain and side chains. Here, the “main chain” refers to the “trunk” portion of the polymer (P), which is the longest chain of atoms. “Having a specific partial structure in the main chain” means that a portion of the polymer main chain different from the terminal has the specific partial structure, and a part of the main chain is constituted by the specific partial structure. do. A "side chain" refers to a portion branched from the "trunk" of a polymer. In the above formula (A), the types of atoms to which the four "*" are respectively bonded are not particularly limited. Preferably, at least two of the four "*" are bonds bonded to carbon atoms and the remainder are bonds bonded to hydrogen atoms. In addition, two or more bonds bonded to carbon atoms among the four "*" may be bonded to different carbon atoms, and two bonds may be bonded to the same carbon atom. good. Also, "*" may be a bond that bonds to an atom that constitutes a part of the ring.

The content ratio of the specific partial structure in the polymer (P) is based on the total monomer units of the polymer (P), from the viewpoint of sufficiently obtaining the effect of improving the applicability (printability) to the substrate and the effect of alleviating the accumulation of residual charges. It is preferably 5 mol % or more, more preferably 10 mol % or more, still more preferably 20 mol % or more, and particularly preferably 30 mol % or more. Moreover, the content ratio of the specific partial structure can be arbitrarily set within a range of 100 mol % or less with respect to the total monomer units of the polymer (P).

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に水素原子又はメチル基である。）

（上記式（５）中、Ｌ^１は単結合又は２価の連結基であり、Ｒ^１及びＲ^２は、それぞれ独立に水素又はメチル基であり、Ａｒ^１は芳香環を表す。）Polymer (P) is preferably a polymer having a structural unit derived from a monomer having a carbon-carbon unsaturated bond. Examples of monomers having a carbon-carbon unsaturated bond include (meth)acrylic compounds, styrene compounds, maleimide group-containing compounds, and the like. In addition, in this specification, "(meth)acryl" is meant to include "acryl" and "methacryl". When the polymer (P) has a specific partial structure in its main chain, the polymer (P) has a structural unit represented by the following formula (1) as a structural unit containing the specific partial structure. is preferred. When the polymer (P) has a specific partial structure in the side chain, the polymer (P) may have a structural unit represented by the following formula (5) as a structural unit containing the specific partial structure. preferable.

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom or a methyl group.)

(In formula (5) above, L ¹ is a single bond or a divalent linking group, R ¹ and R ² are each independently hydrogen or a methyl group, and Ar ¹ represents an aromatic ring.)

The structural unit represented by the above formula (5) has a partial structure derived from an aromatic carboxylic acid anhydride in its side chain. The aromatic ring of Ar ¹ includes a benzene ring, naphthalene ring, anthracene ring and the like. Among these, Ar ¹ is preferably a benzene ring. When L ¹ is a divalent linking group, the divalent linking group includes a divalent hydrocarbon group having 1 to 20 carbon atoms, and the methylene group of the hydrocarbon group is -O-, -COO-, Divalent groups substituted with -NH-, -NHCO- and the like are included.

The polymer (P) contains at least one group selected from the group consisting of a photo-orientation group, a pretilt angle imparting group and a group having a polymerizable carbon-carbon unsaturated bond (hereinafter also referred to as "functional group"). It is preferable to have
(Photo-orientation group)
When the polymer (P) has a photo-aligning group, it is preferable in that a coating film formed using a liquid crystal aligning agent can be provided with liquid crystal alignment ability by light irradiation treatment. A functional group that imparts anisotropy to the film by at least one of photoisomerization reaction, photodimerization reaction, photofries rearrangement reaction, and photodecomposition reaction by light irradiation can be used as the photoorientation group. Specific examples of photo-alignable groups include, for example, azobenzene-containing groups containing azobenzene or derivatives thereof as a basic skeleton, cinnamic acid structure-containing groups containing cinnamic acid or derivatives thereof (cinnamic acid structure) as a basic skeleton, chalcone or derivatives thereof. a chalcone-containing group containing as a basic skeleton, a benzophenone-containing group containing benzophenone or a derivative thereof as a basic skeleton, a phenylbenzoate-containing group containing phenylbenzoate or a derivative thereof as a basic skeleton, a coumarin-containing group containing coumarin or a derivative thereof as a basic skeleton, A cyclobutane-containing structure containing cyclobutane or a derivative thereof as a basic skeleton and the like can be mentioned. The photo-orientation group is at least one selected from the group consisting of cinnamic acid structure-containing groups and phenylbenzoate-containing groups among these, in terms of high sensitivity to light and ease of introduction into polymer side chains. is preferred.

The content of the photo-alignable group is 1 to 70 with respect to all monomer units possessed by the polymer (P), from the viewpoint of sufficiently increasing the liquid crystal alignment of the coating film obtained using the polymer (P). It is preferably mol %, more preferably 3 to 60 mol %.

(Pretilt angle imparting group)
The pretilt angle imparting group is a functional group that imparts the function of inducing a desired pretilt angle to the liquid crystal molecules in the coating film formed using the liquid crystal aligning agent. This pretilt angle imparting group exhibits the property of controlling the alignment of liquid crystal molecules without depending on light irradiation. Specific examples of the pretilt angle imparting group include alkyl groups having 4 to 20 carbon atoms, fluoroalkyl groups having 4 to 20 carbon atoms, alkoxy groups having 4 to 20 carbon atoms, fluoroalkoxy groups having 4 to 20 carbon atoms, and carbon Groups having a steroid skeleton of number 17 to 51, groups in which a plurality of rings (preferably at least one of benzene rings and cyclohexylene rings) are bonded directly or via a linking group, and the like can be mentioned.
The content of the pretilt angle imparting group is preferably 2 to 70 mol %, more preferably 5 to 60 mol %, relative to all monomer units of the polymer (P).

(Group having a polymerizable carbon-carbon unsaturated bond)
Examples of groups having a polymerizable carbon-carbon unsaturated bond include (meth)acryloyl groups, alkenyl groups, vinylphenyl groups, vinyloxy groups and ethynyl groups. Since the polymer (P) has polymerizable carbon-carbon unsaturated bonds in side chains, the polymerizable carbon-carbon unsaturated bonds are utilized between the same or different molecules by light or heat (for example, heating during post-baking). It is preferable in that it is possible to form a covalent bond and form a film with high strength. The content of the group having a polymerizable carbon-carbon unsaturated bond is preferably 1 to 50 mol%, preferably 2 to 40 mol%, based on the total monomer units of the polymer (P). more preferred.

（式（２）中、Ｒ^４及びＲ^５は、それぞれ独立に水素原子又はメチル基であり、Ｒ^３は、炭素数１以上の１価の有機基である。）

（式（３）中、Ｙ^１は、酸素原子、硫黄原子又は－ＮＲ^７－（ただし、Ｒ^７は水素原子又は炭素数１～６のアルキル基である。）であり、Ｒ^６は、単結合又はメチレン基である。「＊」は結合手を表す。）The polymer (P) is a polymer having a structural unit represented by the above formula (1) (hereinafter referred to as “polymer It is particularly preferable to be coalescence (P1)”.
<Polymer (P1)>
The polymer (P1) may have only the structural unit represented by the above formula (1), but a structural unit different from the structural unit represented by the above formula (1) (hereinafter referred to as "other (also referred to as "structural unit"). Preferred specific examples of other structural units include the following structural units (a1) to (a3).
(a1) A partial structure represented by the following formula (2).
(a2) A structural unit having at least one cyclic structure A selected from the group consisting of a cyclic structure represented by the following formula (3) and a cyclic carbonate structure.
(a3) A structural unit having a functional group B that reacts with the ring structure A upon heating in its side chain.

(In formula (2), R ⁴ and R ⁵ are each independently a hydrogen atom or a methyl group, and R ³ is a monovalent organic group having 1 or more carbon atoms.)

(In formula (3), Y ¹ is an oxygen atom, a sulfur atom or —NR ⁷ — (wherein R ⁷ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), and R ⁶ is a single It is a bond or a methylene group."*" represents a bond.)

・ Structural unit (a1)
R ³ in the above formula (2) includes, for example, a monovalent hydrocarbon group having 1 to 30 carbon atoms, and at least one methylene group of the hydrocarbon group is -O-, -CO-, or -COO- or -NR ¹⁶ - (wherein R ¹⁶ is a hydrogen atom or a monovalent hydrocarbon group; the same shall apply hereinafter)-substituted group (hereinafter also referred to as "group α"), 1 having 1 to 30 carbon atoms A group in which at least one hydrogen atom of a valent hydrocarbon group or group α is substituted with a fluorine atom or a cyano group, a monovalent group having a photoalignment group, a monovalent group having a ring structure A, a functional group Examples include a monovalent group having B, a group having a polymerizable carbon-carbon unsaturated bond, and the like.

R ³ is —OR ⁸ or —NR ⁸ R ⁹ (where R ⁸ and R ⁹ are each independently a hydrogen atom or a monovalent is an organic group of.). The monovalent organic groups of R ⁸ and R ⁹ preferably have the above functional groups. A polymer having a structural unit represented by the above formula (1) is used as a precursor, and this polymer (precursor polymer) is reacted with a reactive compound having a functional group to form a polymer side chain. It is suitable in that the functional group can be easily introduced with high efficiency.

・ Structural unit (a2)
Examples of the ring structure represented by formula (3) include structures having rings such as oxetane ring, oxirane ring, thiirane ring, thietane ring, aziridine ring, azetidine ring, and N-methylethyleneimine ring. Cyclic carbonate structures include, for example, structures having rings such as ethylene carbonate and propylene carbonate. As the ring structure A, among these, a structure having an oxetane ring or an oxirane ring is preferable in terms of high reactivity due to heating (post-baking) during film formation.

The polymer (P1) preferably has a ring structure A in its side chain. The ring structure A may be bonded to the atoms (preferably carbon atoms) constituting the main chain with a single bond, but is preferably bonded via a divalent linking group. As the divalent linking group, a divalent hydrocarbon group having 1 to 20 carbon atoms, and 2 obtained by replacing the methylene group of the hydrocarbon group with -O-, -COO-, -NH-, -NHCO-, etc. valent groups and the like. The divalent linking group preferably has 2 to 20 carbon atoms, more preferably 3 to 20 carbon atoms, so that the effect of introducing the ring structure A can be sufficiently obtained. The content of the structural unit (a2) is preferably 0.5 to 60 mol%, more preferably 1 to 40 mol%, based on the total monomer units of the polymer (P1).

・ Structural unit (a3)
The functional group B includes, for example, a carboxyl group, a hydroxyl group, an isocyanate group, an amino group, a group in which each of these groups is protected with a protective group, an alkoxymethyl group, and the like. The functional group B is selected from the group consisting of a carboxyl group and a protected carboxyl group (hereinafter also referred to as a "protected carboxyl group") because of its good storage stability and high reactivity with heating. It is preferable that it is at least one kind of The protected carboxyl group is not particularly limited as long as it is released by heat to form a carboxyl group. Specific examples of the protected carboxyl group include an ester structure in which the carboxyl group of carboxylic acid is protected with a tertiary hydrocarbon group (e.g., t-butyl group, 1-methylcyclopentyl group, etc.), an acetal ester structure of carboxylic acid, carboxylic acid A ketal ester structure of an acid and the like are included. The content of the structural unit (a3) is preferably 0.5 to 60 mol%, more preferably 1 to 40 mol%, based on the total monomer units of the polymer (P1).

Among these structural units (a1) to (a3), the polymer (P1) is capable of imparting alignment ability by photo-alignment treatment while sufficiently improving the applicability to the substrate. ) preferably has a partial structure having a photoalignable group, and it is particularly preferable to have a structural unit (a2) and a structural unit (a3) together with the structural unit (a1). In the polymer (P1), the content of the structural unit represented by the above formula (1) is preferably 5 mol% or more, more preferably 10 mol%, based on the total monomer units of the polymer (P). Above, more preferably 20 mol % or more, particularly preferably 30 mol % or more.
When the polymer (P) is a polymer having a structural unit represented by the above formula (5) (hereinafter also referred to as "polymer (P2)"), the polymer (P2) is represented by the above formula (5) ) having a functional group introduced into the acid anhydride group, the structural unit (a2), and the structural unit (a3).

(Synthesis of polymer (P))
The polymer (P) is preferably obtained by polymerization using a radically polymerizable monomer (hereinafter also referred to as “specific monomer”) having a partial structure represented by the above formula (A). For example, the polymer (P1) can be obtained by radical polymerization of substituted or unsubstituted maleic anhydride (hereinafter also referred to as "maleic anhydride-based compound"). Specific examples of maleic anhydride-based compounds include maleic anhydride, methylmaleic anhydride, and 2,3-dimethylmaleic anhydride. In addition, the maleic anhydride-based compound to be used may be used singly or in combination of two or more.

In the polymerization, a monomer different from the specific monomer (hereinafter also referred to as "other monomer") may be used in combination. The other monomer is not particularly limited as long as it can be radically polymerized with a specific monomer, but is preferably a compound having a carbon-carbon unsaturated bond. Specifically, (meth)acrylic compounds, styrene compounds, Examples include maleimide group-containing compounds. From the viewpoint of ensuring the reliability of the liquid crystal alignment film, the other monomer is preferably at least one selected from the group consisting of (meth)acrylic compounds and styrene compounds.

Other monomers are preferably used to introduce the ring structure A and the functional group B into the side chains of the polymer (P). Therefore, other monomers are selected from the group consisting of a compound having a ring structure A (hereinafter also referred to as "compound (m1)") and a compound having a functional group B (hereinafter also referred to as "compound (m2)"). It preferably contains at least one selected, and more preferably contains the compound (m1) and the compound (m2).

Compound (m1) preferably has an epoxy group (including an oxetanyl group and an oxiranyl group). Specific examples of the compound (m1) include glycidyl (meth)acrylate, glycidyl α-ethylacrylate, 3,4-epoxybutyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, ( 6,7-epoxyheptyl meth)acrylate, (3-ethyloxetane-3-yl)methyl (meth)acrylate, (2-oxo-1,3-dioxolan-4-yl)methyl (meth)acrylate, etc. (Meth) acrylic compounds; styrene compounds such as 3-(glycidyloxymethyl)styrene, 4-(glycidyloxymethyl)styrene, 4-glycidyl-α-methylstyrene; N-(4-glycidyloxyphenyl)maleimide, Examples include maleimide group-containing compounds such as N-glycidylmaleimide. As the compound (m1), one of these may be used alone, or two or more thereof may be used in combination.

Specific examples of the compound (m2) include (meth)acrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid, mesaconic acid, itaconic acid, and the carboxyl groups of these carboxylic acids are protected. (Meth)acrylic compounds such as compounds obtained; 3-vinylbenzoic acid, styrene compounds such as 4-vinylbenzoic acid; 3-maleimidobenzoic acid, 3-maleimidopropionic acid, 3-(2,5-dioxo- Maleimide group-containing compounds such as 3-pyrrolin-1-yl)benzoic acid, 4-(2,5-dioxo-3-pyrrolin-1-yl)benzoic acid, and the like can be mentioned, respectively. As a compound (m2), these 1 type can be used individually or in combination of 2 or more types. When synthesizing the polymer (P1), the ratio of the maleic anhydride-based compound, the compound (m1) and the compound (m2) used is the structural unit represented by the above formula (1) in the polymer (P1), the ring The content ratio of the structure A and the functional group B may be appropriately adjusted so as to be within the above preferable range.

The polymerization reaction is preferably carried out in an organic solvent in the presence of a polymerization initiator. Polymerization initiators to be used include, for example, 2,2′-azobis(isobutyronitrile), 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis(4-methoxy-2 , 4-dimethylvaleronitrile) are preferred. The proportion of the polymerization initiator used is preferably 0.01 to 30 parts by mass with respect to 100 parts by mass of all the monomers used in the reaction. Examples of organic solvents to be used include alcohols, ethers, ketones, amides, esters and hydrocarbon compounds.

In the above polymerization reaction, the reaction temperature is preferably 30° C. to 120° C., and the reaction time is preferably 1 to 36 hours. The amount (a) of the organic solvent used is such that the total amount (b) of the monomers used in the reaction is 0.1 to 60% by mass with respect to the total amount (a+b) of the reaction solution. is preferred. The reaction solution obtained by dissolving the polymer can be obtained by, for example, a method of pouring the reaction solution into a large amount of poor solvent, drying the precipitate obtained under reduced pressure, and a method of distilling off the reaction solution under reduced pressure using an evaporator. After isolating the polymer (P) contained in the reaction solution using a separation method, it is good to use for preparation of a liquid crystal aligning agent.

（式（４）中、Ｒ^１０は、炭素数１以上の１価の有機基であり、Ｘ^１は酸素原子又は－ＮＲ^１１－（Ｒ^１１は水素原子又は炭素数１～５の１価の炭化水素基である。）である。）When obtaining a polymer having a partial structure represented by the above formula (2) as the polymer (P), first, the polymer (P1) is obtained by the above polymerization reaction, and then the polymer (P1) and the polymer A compound (hereinafter also referred to as “reactive compound (E)”) having a group that reacts with the coalescence (P1) and a group ^R3 is reacted. The reactive compound (E) is preferably represented by the following formula (4) in that it has high reactivity with the acid anhydride groups possessed by the polymer (P1) and can increase the modification efficiency of the polymer (P1). It is a compound that

(In formula (4), R ¹⁰ is a monovalent organic group having 1 or more carbon atoms, X ¹ is an oxygen atom or —NR ¹¹ — (R ¹¹ is a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms). It is a hydrocarbon group.)

In the above formula (4), the explanation of R ¹⁰ in the above formula (2) applies to the explanation of R ³ in the above formula (2). R ¹⁰ preferably has a functional group, preferably a photoalignable group or a polymerizable carbon-carbon unsaturated bond. R ¹¹ is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom. The description of the structural unit (a1) above applies to the description of the photoalignable group and the polymerizable carbon-carbon unsaturated bond.

The reaction between the polymer (P1) and the reactive compound (E) is preferably carried out in an organic solvent, optionally in the presence of a catalyst. Catalysts include, but are not limited to, pyridine derivatives such as N,N-dimethylaminopyridine, tertiary amines such as triethylamine. When a catalyst is used, it is preferably used in an amount of 0.01 to 0.5 equivalents with respect to all monomer units of the polymer (P1).

The proportion of the reactive compound (E) used is preferably 1 to 80 mol %, more preferably 3 to 70 mol %, relative to the total monomer units of the polymer (P1). In addition, about a reactive compound (E), you may use 1 type individually and may use it in combination of 2 or more types. When two or more reactive compounds (E) are used in combination, only a compound having a photoalignment group may be used for R ¹⁰ , or only a compound having a polymerizable carbon-carbon unsaturated bond for R ¹⁰ may be used. may be used, or both of these compounds may be used in combination. When synthesizing a polymer having a photo-alignment group and a polymerizable carbon-carbon unsaturated bond as the polymer (P), the proportion of the reactive compound (E) used is the photo-alignment group possessed by the polymer (P). And the proportion of polymerizable carbon-carbon unsaturated bonds is preferably adjusted within the above preferred range.

Examples of organic solvents used in the above reaction include alcohols, ethers, ketones, amides, esters, and hydrocarbon compounds. The reaction temperature for the above reaction is preferably 30° C. to 120° C., and the reaction time is preferably 1 to 24 hours. In this way, a solution is obtained in which the polymer having the partial structure represented by the above formula (2) is dissolved. About this reaction solution, it is good to use a well-known isolation method, and to use for preparation of a liquid crystal aligning agent, after isolating the polymer (P) contained in a reaction solution.

The polystyrene equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the polymer (P) is preferably 1,000 to 300,000, more preferably 2,000 to 100,000. is. The molecular weight distribution (Mw/Mn) represented by the ratio of Mw to the polystyrene equivalent number average molecular weight (Mn) measured by GPC is preferably 8 or less, more preferably 6 or less. In addition, only 1 type may be sufficient as the polymer (P) used for preparation of a liquid crystal aligning agent, and it may combine 2 or more types.

The content of the polymer (P) in the liquid crystal aligning agent is determined from the viewpoint of sufficiently increasing the applicability of the liquid crystal aligning agent to the substrate and sufficiently obtaining the effect of reducing the amount of accumulated charge in the liquid crystal aligning agent. is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, and still more preferably 3% by mass or more, relative to the total amount of the polymer components contained in 4. 5% by mass or more is particularly preferred. Further, the content of the polymer (P) is preferably 90% by mass or less, more preferably 70% by mass or less, and even more preferably 50% by mass or less, relative to the total amount of the polymer components contained in the liquid crystal aligning agent. 40 mass % or less is particularly preferable.

(solvent)
The liquid crystal aligning agent of the present disclosure is at least one selected from the group consisting of compounds represented by the above formulas (E-1) to (E-5), and has a boiling point of 190° C. at 1 atm. It contains the following organic solvents (hereinafter also referred to as “specific solvents”). In addition, as a specific solvent, you may use individually by 1 type, and may use it in combination of 2 or more types.

- A compound represented by the formula (E-1) In the above formula (E-1), the alkyl group having 1 to 3 carbon atoms for R ⁴⁰ , R ⁴¹ and R ⁴³ includes a methyl group, an ethyl group and a propyl group. , which may be linear or branched. R ⁴⁰ , R ⁴¹ and R ⁴³ are preferably methyl or ethyl groups. The alkanediyl group having 1 to 4 carbon atoms possessed by R ⁴² includes a methylene group, an ethylene group and a propanediyl group, and these may be linear or branched. When R ⁴² is an alkanediyl group having 1 to 3 carbon atoms, it preferably has 2 or 3 carbon atoms. r is preferably 1 or 2, more preferably 1.

Specific examples of the compound represented by the above formula (E-1) include propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether (DEDG), diethylene glycol ethyl methyl ether, 3-methoxy-1-butanol, ethylene glycol monomethyl ether. , ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether and other polyhydric alcohol partial ethers;
Partial esters of polyhydric alcohols such as diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, and the like. Among these, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol diethyl ether, 3-methoxy-1-butanol and propylene glycol monomethyl ether acetate are preferred, and more than propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate and diethylene glycol diethyl ether. At least one selected from the group consisting of is particularly preferred.

• Compound Represented by Formula (E-2) In the above formula (E-2), R ⁴⁴ is preferably linear, more preferably an ethylene group or a propanediyl group. Specific examples of the compound represented by the above formula (E-2) include cyclobutanone, cyclopentanone, cyclohexanone, cycloheptanone and the like. Among these, at least one of cyclopentanone and cyclohexanone is preferred.

Compound Represented by Formula (E-3) In the above formula (E-3), R ⁴⁵ and R ⁴⁶ may be linear or branched, but are preferably branched. Specific examples of R ⁴⁵ and R ⁴⁶ include, in addition to the above alkyl groups having 1 to 3 carbon atoms, n-butyl group, isobutyl group, 3-methylbutyl group, 2,2-dimethylpropyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group and the like. The number of carbon atoms in each of R ⁴⁵ and R ⁴⁶ is preferably 6 or less, more preferably 5 or less. In addition, each of R ⁴⁵ and R ⁴⁶ preferably has 2 or more carbon atoms, more preferably 3 or more carbon atoms.

Specific examples of the compound represented by the above formula (E-3) include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, di-n-butyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, diisobutyl ketone, trimethylnonanone and the like. Among these, at least one selected from the group consisting of diisobutyl ketone, methyl ethyl ketone and methyl-i-butyl ketone is preferred, and diisobutyl ketone is particularly preferred.

- A compound represented by the formula (E-4) In the above formula (E-4), the divalent hydrocarbon group of R ⁵⁰ is a linear or branched alkanediyl group, cycloalkanediyl group or phenylene group is preferred, and a linear or branched alkanediyl group is more preferred. The number of carbon atoms in the divalent hydrocarbon group of R ⁵⁰ is preferably 7 or less, more preferably 6 or less.

Specific examples of compounds represented by formula (E-4) include methanol, ethanol, propanol, butanol, pentanol, 3-methyl-1-butanol, 1-hexanol, 2-hexanol, heptanol, phenol, and cyclohexanol. , methylcyclohexanol, diacetone alcohol; and polyhydric alcohols such as propane-1,2-diol. Among these, at least one selected from the group consisting of diacetone alcohol, propanol, butanol and pentanol is preferred, and diacetone alcohol is particularly preferred.

• Compound Represented by Formula (E-5) In the above formula (E-5), the monovalent hydrocarbon group for R ⁵¹ is preferably a linear or branched alkyl group. Preferably, R ⁵¹ has 1 to 3 carbon atoms. R ⁵² is preferably a linear or branched alkyl group. Preferably, R ⁵² has 1 to 4 carbon atoms.

Specific examples of the compound represented by formula (E-5) include methyl acetate, ethyl acetate, propyl acetate, n-butyl acetate, i-butyl acetate, sec-butyl acetate, t-butyl acetate, and 3-methoxy acetate. Butyl, methyl acetoacetate, ethyl acetoacetate, ethyl propionate, n-butyl propionate, methyl lactate, ethyl lactate, n-butyl lactate and the like. Among these, at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, n-butyl acetate and i-butyl acetate is preferable, and at least one of n-butyl acetate and i-butyl acetate. is particularly preferred.

The content ratio of the specific solvent (the total amount when two or more types are contained) is such that the effect of improving the wetting and spreading property of the liquid crystal aligning agent on the substrate and the effect of reducing the residual charge in the liquid crystal element can be sufficiently obtained. , With respect to the total amount of the solvent contained in the liquid crystal aligning agent, it is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, 20% by mass % or more is particularly preferable. Further, when other solvents are used in combination, the content of the specific solvent is preferably 90% by mass or less, and preferably 80% by mass or less, relative to the total amount of the solvent contained in the liquid crystal aligning agent. More preferably, it is 70% by mass or less, and particularly preferably 60% by mass or less.

As the specific solvent, the group consisting of the above formulas (E-1) to (E-3) and (E-5) among the above, in that it is highly effective in reducing the wetting and spreading of the substrate and the residual charge. It is preferably at least one selected from, and more preferably at least one selected from the group consisting of formulas (E-1) and (E-2) above.

The solvent component of the liquid crystal aligning agent may consist of only the specific solvent, or may be a mixed solvent of a solvent other than the specific solvent (hereinafter also referred to as "other solvent") and the specific solvent. . Other solvents include, for example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, Highly polar solvents such as N,N-dimethylacetamide (hereinafter also referred to as "first solvent");
Solvents such as butyl cellosolve (ethylene glycol monobutyl ether), tetrahydrofuran, diisopentyl ether, ethylene carbonate, propylene carbonate, cyclohexane, hexane, heptane, octane, benzene, toluene, xylene, dichloromethane, 1,2-dichloroethane (hereinafter referred to as "second 2 solvent”) and the like. These can be used individually by 1 type or in mixture of 2 or more types.

When the liquid crystal aligning agent contains other solvents, the content ratio of the first solvent (the total amount when containing two or more kinds) is preferably 1 with respect to the total amount of the solvent contained in the liquid crystal aligning agent. It is at least 2% by mass, more preferably at least 2% by mass. Moreover, the upper limit of the content rate of a 1st solvent is 70 mass % or less, More preferably, it is 60 mass % or less with respect to the total amount of the solvent contained in a liquid crystal aligning agent. The content ratio of the second solvent (the total amount when two or more kinds are contained) is preferably 10% by mass or more, more preferably 20% by mass or more, relative to the total amount of the solvents contained in the liquid crystal aligning agent. be. Moreover, the upper limit of the content rate of a 2nd solvent is 70 mass % or less, More preferably, it is 60 mass % or less with respect to the total amount of the solvent contained in a liquid crystal aligning agent.

<Other ingredients>
Although the liquid crystal aligning agent of the present disclosure contains the polymer (P) and the specific solvent as described above, it may contain other components other than the polymer (P) and the specific solvent, if necessary. .

(Polymer (Q))
The liquid crystal aligning agent of the present disclosure is a polymer ( Q) is preferably further contained.

Examples of the polymer (Q) include polyamic acids, polyimides, polyamic acid esters, polyamides, polyorganosiloxanes, polymers of monomers having unsaturated bonds, and the like. When the polymer (Q) is a polymer having a functional group that reacts with the ring structure A, the interaction between the polymer (P) and the polymer (Q) can be enhanced, and the performance of the obtained liquid crystal device can be made higher. Examples of the functional group that the polymer (Q) has and reacts with the ring structure A include a carboxyl group, a hydroxyl group, an isocyanate group, an amino group, a group in which each of these groups is protected with a protecting group, an alkoxymethyl group, and the like. . Preferably, it is at least one selected from the group consisting of carboxyl groups and protected carboxyl groups.

From the viewpoint of improving electrical properties, affinity with liquid crystals, mechanical strength, and affinity with the polymer (P), the polymer (Q) is, among others, polyamic acid, polyamic acid ester, polyimide, and unsaturated bond is preferably at least one selected from the group consisting of polymers of monomers having Examples of polymers of monomers having unsaturated bonds include (meth)acrylic polymers, styrene polymers, and maleimide polymers. However, the polymer of the monomer having an unsaturated bond as the polymer (Q) differs from the polymer (P) in that it does not have the structural unit represented by the above formula (1). When the polymer (Q) is a polymer of a monomer having an unsaturated bond, the polymer is, among these, a (meth)acrylic having no structural unit represented by the above formula (1) It is preferably a system polymer.

The content of the polymer (Q) is the polymer (P) contained in the liquid crystal aligning agent from the viewpoint of achieving a well-balanced effect of blending the polymer (Q) and the effect of blending the polymer (P). With respect to 100 parts by mass, it is preferably 100 parts by mass or more, more preferably 150 parts by mass or more, and still more preferably 200 parts by mass or more. In addition, the content of the polymer (Q) is preferably 3500 parts by mass or less, more preferably 3000 parts by mass or less, and particularly preferably 2000 parts by mass or less with respect to 100 parts by mass of the polymer (P). is.

Other components include, in addition to the above, low-molecular weight compounds having at least one epoxy group in the molecule and having a molecular weight of 1000 or less (e.g., ethylene glycol diglycidyl ether, N,N,N',N'-tetraglycidyl- m-xylenediamine, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, etc.), functional silane compounds, polyfunctional (meth)acrylates, antioxidants, metal chelate compounds, curing accelerators agents, surfactants, fillers, dispersants, photosensitizers and the like. The mixing ratio of other components can be appropriately selected according to each compound within a range that does not impair the effects of the present disclosure.

The solid content concentration in the liquid crystal aligning agent (ratio of the total mass of components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc., but preferably It is in the range of 1 to 10% by mass. When the solid content concentration is 1% by mass or more, the film thickness of the coating film can be sufficiently secured, and a favorable liquid crystal alignment film can be easily obtained. On the other hand, when the solid content concentration is 10% by mass or less, the film thickness of the coating film does not become excessively large, making it easy to obtain a good liquid crystal alignment film. can be suppressed.

A particularly preferable solid content concentration range varies depending on the method used when applying the liquid crystal aligning agent to the substrate. For example, when the spin coating method is used, a solid content concentration in the range of 1.5 to 4.5% by weight is particularly preferred. When the offset printing method is used, it is particularly preferable to set the solid content concentration in the range of 3 to 9% by weight, thereby setting the solution viscosity in the range of 12 to 50 mPa·s. In the case of ink jet printing, it is particularly preferable to set the solid content concentration in the range of 1 to 8% by weight, thereby setting the solution viscosity in the range of 3 to 20 mPa·s. The temperature for preparing the liquid crystal aligning agent is preferably 10 to 50°C, more preferably 20 to 30°C.

The composition containing the polymer (P) having the specific partial structure and the specific solvent has a low surface tension, which improves the spreadability on the substrate and improves the coatability. It is presumed that the residual charge of the liquid crystal element could be reduced due to the small amount of solvent remaining in the film. Further, when the polymer (Q) is further contained, it is presumed that the state of separation between the polymer (P) and the polymer (Q) changed, thereby contributing to the reduction of the residual charge in the liquid crystal element. be done. It should be noted that this is an assumption and does not limit the content of the present disclosure.

<<Liquid crystal alignment film and liquid crystal element>>
The liquid crystal alignment film of the present disclosure is formed from the liquid crystal alignment agent prepared as described above. Moreover, the liquid crystal element of this indication comprises the liquid crystal aligning film formed using the liquid crystal aligning agent demonstrated above. The operation mode of the liquid crystal in the liquid crystal element is not particularly limited. Field Switching) type, OCB (Optically Compensated Bend) type, and PSA type (Polymer Sustained Alignment) type. A liquid crystal element can be manufactured, for example, by a method including steps 1 to 3 below. Step 1 uses different substrates depending on the desired mode of operation. Steps 2 and 3 are common to each operation mode.

<Step 1: Formation of coating film>
First, a liquid crystal aligning agent is applied onto a substrate, and preferably the coated surface is heated to form a coating film on the substrate. Examples of the substrate include glass such as float glass and soda glass; and transparent substrates made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefin). Examples of the transparent conductive film provided on one surface of the substrate include an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), and the like. can be used. When manufacturing a TN-type, STN-type or VA-type liquid crystal element, two substrates provided with patterned transparent conductive films are used. On the other hand, when manufacturing an IPS-type or FFS-type liquid crystal element, a substrate provided with electrodes patterned in a comb shape and a counter substrate provided with no electrodes are used. Application of the liquid crystal aligning agent to the substrate is preferably performed on the electrode forming surface by an offset printing method, a spin coating method, a roll coater method or an inkjet printing method. The liquid crystal aligning agent of the present disclosure is preferable in that clogging of the inkjet head due to the liquid crystal aligning agent can be sufficiently suppressed when an inkjet printing method is employed as a coating method.

After applying the liquid crystal aligning agent, preheating (pre-baking) is preferably carried out for the purpose of preventing dripping of the applied liquid crystal aligning agent. The pre-baking temperature is preferably 30-200° C., and the pre-baking time is preferably 0.25-10 minutes. Thereafter, the solvent is completely removed and, if necessary, a baking (post-baking) step is performed for the purpose of thermal imidization of the amic acid structures present in the polymer. The baking temperature (post-baking temperature) at this time is preferably 80 to 250.degree. C., more preferably 80 to 200.degree. The post-bake time is preferably 5-200 minutes. In particular, the polymer (P) has good solubility in low boiling point solvents, and even when the post-baking temperature is set to, for example, 200° C. or less, preferably 180° C. or less, more preferably 160° C. or less, the liquid crystal orientation is And it is preferable in that it is possible to obtain a liquid crystal element having excellent electrical characteristics. The thickness of the film thus formed is preferably 0.001 to 1 μm.

<Step 2: Alignment treatment>
When manufacturing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal element, the coating film formed in step 1 above is subjected to a treatment (orientation treatment) for imparting liquid crystal orientation ability. As a result, the coating film is provided with the ability to align liquid crystal molecules to form a liquid crystal alignment film. As the alignment treatment, the coating film formed in step 1 is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, cotton, etc., and the coating film formed on the substrate is irradiated with light. and a photo-alignment treatment for imparting liquid crystal alignment ability to the coating film. On the other hand, when manufacturing a vertically aligned liquid crystal element, the coating film formed in the above step 1 can be used as a liquid crystal alignment film as it is. Orientation treatment may be performed.

When the photo-alignment treatment is used, ultraviolet rays and visible rays including light having a wavelength of 150 to 800 nm can be used as the radiation to irradiate the coating film. Ultraviolet rays including light with a wavelength of 200 to 400 nm are preferred. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, irradiation may be performed in a direction perpendicular to the substrate surface, obliquely, or a combination thereof. In the case of non-polarized radiation, the irradiation direction is oblique. Examples of light sources to be used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, excimer lasers, and the like. The dose of radiation is preferably 100 to 50,000 J/m ² , more preferably 150 to 20,000 J/m ² .

<Step 3: Construction of liquid crystal cell>
A liquid crystal cell is manufactured by preparing two substrates on which the liquid crystal alignment films are formed as described above, and arranging the liquid crystal between the two substrates facing each other. In order to manufacture a liquid crystal cell, for example, two substrates are arranged facing each other with a gap therebetween so that the liquid crystal alignment films face each other, and the peripheral portions of the two substrates are bonded together using a sealant, and the surfaces of the substrates are bonded together. A method of injecting and filling a liquid crystal into a cell gap surrounded by a sealant to seal an injection hole, a method of using an ODF method, and the like can be used. As the sealing agent, for example, an epoxy resin or the like containing a curing agent and aluminum oxide spheres as spacers can be used. Liquid crystals include nematic liquid crystals and smectic liquid crystals, among which nematic liquid crystals are preferred. In the PSA mode, after the liquid crystal cell is constructed, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates.

Subsequently, if necessary, a polarizing plate is attached to the outer surface of the liquid crystal cell to form a liquid crystal element. Examples of the polarizing plate include a polarizing plate in which a polarizing film called "H film" in which iodine is absorbed while stretching orientation of polyvinyl alcohol is sandwiched between cellulose acetate protective films, or a polarizing plate composed of the H film itself.

The liquid crystal element of the present disclosure can be effectively applied to various uses, such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smart phones, and various monitors. , various display devices such as liquid crystal televisions and information displays, light control films, retardation films, and the like.

The present disclosure will be specifically described below with reference to examples, but the content of the present disclosure is not limited to the following examples.

In the following examples, the weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw/Mn) of the polymer were measured by the following methods.
<Weight average molecular weight, number average molecular weight and molecular weight distribution>
Mw and Mn were measured by gel permeation chromatography (GPC) under the following conditions. Also, the molecular weight distribution (Mw/Mn) was calculated from the obtained Mw and Mn.
・Apparatus: "GPC-101" of Showa Denko K.K.
· GPC column: Shimadzu GLC Co., Ltd. "GPC-KF-801", "GPC-KF-802", "GPC-KF-803" and "GPC-KF-804" combined Mobile phase: tetrahydrofuran (THF), or N,N-dimethylformamide solution containing lithium bromide and phosphoric acid Column temperature: 40° C., flow rate: 1.0 mL/min, sample concentration: 1.0% by mass, sample injection volume: 100 μL, detector : Differential refractometer, standard material: monodisperse polystyrene

The compounds used in the examples below are shown below. In addition, hereinafter, for the sake of convenience, the "compound represented by formula (X)" may be simply referred to as "compound (X)".

<Synthesis of polymer>
[Synthesis Example 1-1: Synthesis of polymer (A-1)]
Under nitrogen, 9.8 g (100 mmol) of maleic anhydride as a polymerization monomer and 1.0 g (4.0 mmol) of 2,2′-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator are placed in a 100 mL two-necked flask. ), 0.2 g (0.8 mmol) of 2,4-diphenyl-4-methyl-1-pentene as a chain transfer agent, and 44 g of tetrahydrofuran as a solvent were added and polymerized at 70° C. for 5 hours. After reprecipitation in n-hexane, the precipitate was filtered and vacuum-dried at room temperature for 8 hours to obtain the desired polymer (A-1). This polymer (A-1) had a weight average molecular weight Mw of 40,000 and a molecular weight distribution Mw/Mn of 3.4 as measured by GPC in terms of polystyrene.

[Synthesis Examples 1-2 to 1-6]
Polymerization was carried out in the same manner as in Synthesis Example 1-1 except that the types and molar ratios of the polymerization monomers used were as shown in Table 1 below, and a polymer ( A-2) to (A-4), (R-1) and (R-2) were obtained. The total number of moles of polymerized monomers was 100 mmol as in Synthesis Example 1-1. The numerical values in Table 1 represent the charged amount (mol %) of each monomer with respect to all the monomers used in polymer synthesis.

[Synthesis Example 2-1: Synthesis of polymer (P-1)]
Polymerization was carried out in the same manner as in Synthesis Example 1-1 above to obtain a tetrahydrofuran solution containing the polymer (A-1), and then the compound (AM-1) was added to the monomer before reprecipitation in n-hexane. 20 mol% with respect to the total amount of the amount, 30 mol% of the compound (ALM-1) with respect to the total amount of the charged amount of the monomers, and 1% by weight of pyridine with respect to the above tetrahydrofuran solution. After reacting for a period of time, it was reprecipitated in n-hexane to obtain the desired polymer (P-1).

[Synthesis Examples 2-2 to 2-4: Synthesis of Polymers (P-2) to (P-4)]
The same procedure as in Synthesis Example 2-1 was performed except that the type of the precursor polymer and the type and amount of the reactive compound (E) were changed as shown in Table 2 below to obtain polymers (P-2) to (P-4) was obtained. The numerical values in Table 2 represent the charged amount [mol%] of each reactive compound (E) with respect to all the monomers used in the synthesis of the precursor polymer.

[Synthesis Example 3-1: Synthesis of polymer (Q-1)]
100 mol parts of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 100 mol parts of p-phenylenediamine are dissolved in NMP and reacted at 40° C. for 3 hours to obtain a polyamic acid polymer ( A solution containing 10% by mass of Q-1) was obtained.

[Synthesis Example 3-2: Synthesis of polymer (Q-2)]
The above polymer (Q-1) is dissolved in NMP to obtain a solution having a concentration of 10% by mass, and 1 mol each of pyridine and acetic anhydride are added to 1 mol of the tetracarboxylic dianhydride used in the polymerization. Then, a dehydration ring-closure reaction was carried out at 100° C. for 8 hours. After completion of the reaction, the reaction mixture was poured into a large excess of methanol to precipitate the reaction product. After the collected precipitate was washed with methanol, it was dried at 40° C. under reduced pressure for 15 hours to obtain a polyimide polymer (Q-2). The imidization rate of the obtained polymer was 70%.

[Synthesis Example 3-3: Synthesis of polymer (Q-3)]
-Synthesis of compound (DE-1a/b) According to the scheme below, a mixture (DE-1a/b) of a compound represented by the following formula (DE-1a) and a compound represented by the following formula (DE-1b) got

22.42 g (100 mmol) of compound (TA-3), 100 mL of tetrahydrofuran, and 0.79 g (10.0 mmol) of pyridine are placed in a 200 mL three-necked flask equipped with a nitrogen inlet tube, a reflux condenser, and a thermometer, and placed under a nitrogen stream. was stirred to suspend. 15.14 g (210 mmol) of β-methallyl alcohol was added to this suspension, and the mixture was stirred at room temperature for 2 hours. Further reaction was carried out at 60° C. for 8 hours to obtain a colorless and transparent solution. This reaction solution was concentrated under reduced pressure at 60° C. and further vacuum dried to obtain 36.84 g of a mixture (DE-1a/b).

・Synthesis of compound (DC-1a)

18.42 g (50.0 mmol) of the mixture (DE-1a/b) and 100 mL of toluene were placed in a 100 mL eggplant flask equipped with a nitrogen inlet tube and a reflux condenser, and the mixture was stirred at 80° C. for 30 minutes. After that, the mixture was cooled to room temperature while stirring, and further stirred at room temperature for 30 minutes. The resulting suspension was filtered and washed twice with 5 mL of toluene. The obtained solid was vacuum-dried at 60° C. to obtain 15.47 g of white powder compound (DE-1a) (42.0 mmol, yield 84%).

Then, 14.74 g (40.0 mmol) of compound (DE-1a), 80 mL of heptane, and 0.032 g (0.40 mmol) of pyridine were placed in a 500 mL three-necked flask equipped with a nitrogen inlet tube, a reflux condenser and a thermometer. and stirred at 75° C. under a nitrogen stream. 14.28 g (120 mmol) of thionyl chloride was slowly added dropwise over 20 minutes, and foaming was confirmed as the reaction progressed. After completion of the dropwise addition, reaction was carried out at 75° C. for 2 hours to obtain a colorless and transparent solution. The reaction solution was concentrated under reduced pressure at 60° C. to distill off excess thionyl chloride. 80 mL of heptane was added to the obtained liquid, and the mixture was stirred at room temperature, and the precipitated insoluble matter was removed by filtration. The filtrate was concentrated under reduced pressure at 60° C. and further dried under high vacuum at 60° C. for 4 hours to obtain 15.89 g of colorless transparent liquid compound (DC-1a) (39.2 mmol, yield 98%).

- Synthesis of polymer (Q-3) In a 50 mL three-necked flask equipped with a nitrogen inlet tube and a thermometer, 3.89 g (9.6 mmol) of compound (DC-1a) and 5.19 g of compound (DA-1) (10.0 mmol), 58.2 g of NMP, and 0.51 g (5.0 mmol) of triethylamine were added, cooled to about 10° C., and 8.30 g (30.0 mmol) of DMT-MM, a triazine-based dehydration condensation agent. In addition, the mixture was reacted at room temperature for 24 hours under a nitrogen stream. The resulting polymerization solution was diluted with NMP and slowly poured into methanol with stirring to solidify. The precipitated solid was collected, washed with stirring in methanol twice, and vacuum-dried at 60° C. to obtain a white powder polyamic acid ester polymer (Q-3). This polymer (Q-3) had a number average molecular weight Mn of 11,000 and a molecular weight distribution Mw/Mn of 3.0. This polymer (Q-3) had a number average molecular weight Mn of 11,000 and a molecular weight distribution Mw/Mn of 3.0 as measured by GPC in terms of polystyrene.

[Synthesis Example 3-4: Synthesis of polymer (Q-4)]
3,4-epoxycyclohexylmethyl methacrylate 3.39 g (17.3 mmol), methacrylic acid 0.37 g (4.3 mmol), 2,2'-azobis (2,4-dimethylvaleronitrile) 0 as a radical polymerization initiator .12 g (0.5 mmol) and 15 g of NMP as solvent were added and polymerized at 60° C. for 24 hours under nitrogen. The weight average molecular weight Mw of the obtained polymer (Q-4) measured in terms of polystyrene by GPC was 30,000, and the molecular weight distribution Mw/Mn was 2.

<Production and evaluation of vertical optical liquid crystal display device>
[Example 1]
1. Preparation of liquid crystal aligning agent (AL-1) 10 parts by weight of the polymer (P-1) obtained in Synthesis Example 2-1 and 100 parts by weight of the polymer (Q-1) obtained in Synthesis Example 3-1 Propylene glycol methyl ether (PGME), butyl cellosolve (BC) and N-methylpyrrolidone (NMP) are added as solvents to (solid content of polymer), and the solvent composition is PGME/BC/NMP = 40/50/10 (mass ratio) and a solid content concentration of 4.0% by mass. A liquid crystal aligning agent (AL-1) was prepared by filtering this solution through a filter having a pore size of 1 μm.

2. Evaluation of Applicability (Wetting Spreadability) A simple evaluation of inkjet applicability of the liquid crystal aligning agent (AL-1) prepared above was performed. As an inkjet device, an inkjet coating device IJ-6021 (manufactured by Shibaura Mechatronics Co., Ltd.) was used. For coating, the liquid crystal aligning agent (AL-1) was ejected from one of the 256 ejection heads onto the glass substrate with a transparent electrode made of an ITO film at an ejection rate of 360 pl/sec and a stage speed of 600 mm/sec. After that, it was allowed to stand for 1 minute, and was calcined on a hot plate at 100° C. for 2 minutes. After the calcination, the width (line width) of the linear film formed on the substrate was observed with a microscope. Five films were produced, and the average value of the line width of each film was calculated. "Good (A)" when the average value of the line width of the five films was 800 μm or more, "Fair (B)" when it was 700 μm or more and less than 800 μm, and "Bad" when it was less than 700 μm (C)”. As a result, the wetting and spreading property was evaluated as "good (A)" in this example.

3. Evaluation of Discharge Stability Regarding the liquid crystal aligning agent (AL-1), ink jet head clogging was evaluated by the degree of discharge failure after idling using an ink jet coating apparatus IJ-6021. As a test method, the inkjet device IJ-6021 was filled with a liquid crystal aligning agent (AL-1), and after idling for 60 minutes, the liquid crystal aligning agent (AL-1) was ejected at 256 points on the liquid-repellent sheet, and ejection missing. counted the number of In this case, defects in an area of 50% or more of the normal ejection area were counted as missing ejections. The evaluation is as follows: "Good (A)" when the number of ejection failures is less than 5 points; gone. In this example, the ejection stability was evaluated as "good (A)".

4. Manufacture of vertical light liquid crystal display element On the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film, the liquid crystal aligning agent (AL-1) prepared above is applied using a spinner and a hot plate at 80 ° C. was pre-baked for 1 minute. After that, it was heated at 230° C. for 1 hour in an oven whose interior was replaced with nitrogen to form a coating film having a thickness of 0.1 μm. Next, the surface of this coating film is irradiated with 200 J/m ² of polarized ultraviolet light containing an emission line of 313 nm using a Hg-Xe lamp and a Glan-Taylor prism from a direction inclined at 40° from the normal to the substrate to impart liquid crystal alignment ability. bottom. The same operation was repeated to prepare a pair (two sheets) of substrates each having a liquid crystal alignment film.
Next, an epoxy resin adhesive containing aluminum oxide spheres with a diameter of 3.5 μm was applied to the outer periphery of the surface of one of the substrates having the liquid crystal alignment film by screen printing, and then the liquid crystal alignment film surfaces of the pair of substrates were coated. The substrates were opposed to each other and pressed so that the direction of projection of the optical axis of the ultraviolet rays onto the substrate surface was antiparallel, and the adhesive was thermally cured at 150° C. for 1 hour. Next, the gap between the substrates was filled with a negative liquid crystal (MLC-6608, manufactured by Merck Co.) through the liquid crystal inlet, and the liquid crystal inlet was sealed with an epoxy adhesive. Furthermore, in order to eliminate the flow alignment during liquid crystal injection, this was heated at 130° C. and then slowly cooled to room temperature. Next, polarizing plates are attached to both outer surfaces of the substrate so that their polarization directions are orthogonal to each other and form an angle of 45° with the direction of projection of the optical axis of the ultraviolet rays of the liquid crystal alignment film onto the substrate surface. A liquid crystal display device was manufactured by

5. Measurement of Charge Accumulation (RDC) Using the liquid crystal display element manufactured as described above, after applying a DC voltage of 2 V at 71° C. for 10 minutes, short-circuit for 0.2 seconds and then keep it open for 10 minutes. The voltage accumulated in the liquid crystal display element (A1) when the liquid crystal display element (A1) was turned on was measured by a dielectric absorption method. The evaluation is "good (A)" when the charge accumulation amount is 0.1 V or less, "good (B)" when the charge accumulation amount is greater than 0.1 V and 0.2 V or less, and the charge accumulation amount is greater than 0.2V, it was defined as "defective (C)". As a result, the evaluation of the charge storage amount of this liquid crystal display element was good (A).

[Examples 2, 4 to 7 and Comparative Examples 1 to 3]
Except for changing the formulation composition as shown in Table 3 below, preparation was performed at the same solid content concentration as in Example 1, and liquid crystal aligning agents (AL-2), (AL-4) to (AL-7), (BL- 1) to (BL-3) were obtained respectively. Further, using each liquid crystal aligning agent, the applicability and ejection stability of the liquid crystal aligning agent were evaluated in the same manner as in Example 1, and a vertical light liquid crystal display element was manufactured in the same manner as in Example 1. Various evaluations were performed. The results are shown in Table 4 below.

<Production and Evaluation of Rubbing Horizontal Liquid Crystal Display Device>
[Example 3]
1. Preparation of liquid crystal aligning agent (AL-3) The polymers used are 20 parts by mass of the polymer (A-1) obtained in Synthesis Example 1-1 and the polymer obtained in Synthesis Example 3-2 ( Q-2) A liquid crystal aligning agent (AL-3) was prepared in the same manner as in Example 1 except that the content was changed to 100 parts by mass and the solvent composition was changed as shown in Table 3 below.

2. Evaluation of Wetting Spreadability and Discharge Stability Wet spreadability and discharge stability were evaluated in the same manner as in Example 1 except that (AL-3) was used instead of (AL-1) as the liquid crystal aligning agent. rice field. As a result, this liquid crystal aligning agent (AL-3) was evaluated as "A" for wet spreadability and "A" for ejection stability.

3. Manufacture of rubbed horizontal liquid crystal display element On the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film, the liquid crystal aligning agent (AL-3) prepared above was applied using a spinner and a hot plate at 80 ° C. was pre-baked for 1 minute. After that, it was heated at 230° C. for 1 hour in an oven whose interior was replaced with nitrogen to form a coating film having a thickness of 0.1 μm. This coating film was subjected to rubbing treatment using a rubbing machine having a roll wrapped with rayon cloth at a roll rotation speed of 400 rpm, a stage moving speed of 3 cm/sec, and a pile pushing length of 0.1 mm. After that, the substrate was ultrasonically cleaned in ultrapure water for 1 minute and then dried in a 100° C. clean oven for 10 minutes to obtain a substrate having a liquid crystal alignment film. By repeating this series of operations, a pair (two sheets) of substrates having a liquid crystal alignment film was produced.
Next, an epoxy resin adhesive containing aluminum oxide spheres with a diameter of 3.5 μm was applied to the outer periphery of the surface of one of the substrates having the liquid crystal alignment film by screen printing, and then the liquid crystal alignment film surfaces of the pair of substrates were placed facing each other. Then, the substrates were press-bonded so that the projection direction of the optical axis of the ultraviolet rays onto the substrate surface was horizontal, and the adhesive was thermally cured at 150° C. for 1 hour. Next, the gap between the substrates was filled with a positive liquid crystal (MLC-7028-100, manufactured by Merck Co.) through the liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Furthermore, in order to eliminate the flow alignment during liquid crystal injection, this was heated at 130° C. and then slowly cooled to room temperature. Next, polarizing plates are attached to both outer surfaces of the substrate so that their polarization directions are orthogonal to each other and form an angle of 90° with the direction of projection of the optical axis of the ultraviolet rays of the liquid crystal alignment film onto the substrate surface. A liquid crystal display device was manufactured by

4. Measurement of Charge Storage Amount (RDC) A charge storage amount (RDC) was measured in the same manner as in Example 1 for the rubbing horizontal liquid crystal display device manufactured as described above. As a result, the charge storage amount (RDC) was evaluated as "A" in this example.

In Table 3, the numerical values of Solvents 1 to 3 indicate the usage ratio (parts by mass) of each solvent with respect to the total amount of solvents used in the preparation of the liquid crystal aligning agent. Abbreviations of solvents in Table 3 have the following meanings.
PGME: propylene glycol monomethyl ether BC: butyl cellosolve NMP: N-methyl-2-pyrrolidone DEDG: diethylene glycol diethyl ether CHN: cyclohexanone DIBK: diisobutyl ketone

As can be seen from the results of Examples 1 to 7 above, the liquid crystal aligning agents (AL-1) to (AL-7) containing the polymer (P) and the specific solvent had a small amount of accumulated residual charge. In addition, it was found that the liquid crystal aligning agents (AL-1) to (AL-7) had good wetting and spreading properties through evaluation of coating properties using an inkjet device. Further, the liquid crystal aligning agents (AL-1) to (AL-7) were also evaluated as good in terms of ejection stability when the inkjet device was ejected after idling, indicating that ejection defects can be suppressed. On the other hand, in Comparative Example 1 in which the liquid crystal aligning agent contains the polymer (P) but does not contain the specific solvent, the ejection stability is good, but the liquid crystal display element remains as compared to Examples 1 to 7. A large amount of electric charge was accumulated, and the wetting and spreading property of the liquid crystal aligning agent was inferior to that of the examples. Moreover, in Comparative Examples 2 and 3, in which maleimide-based polymers were used in place of the polymer (P), the wet spreadability, the ejection stability, and the amount of residual accumulated charges were all inferior to those of the Examples.

From these results, it has become clear that the liquid crystal aligning agent containing the polymer (P) and the specific solvent is excellent in coatability and discharge stability with respect to substrates, and can provide a liquid crystal element with a small amount of accumulated residual charge. rice field.

Claims (7)

a polymer (P) having a partial structure represented by the following formula (A);
a polymer (Q) different from the polymer (P);
At least one compound selected from the group consisting of compounds represented by the following formulas (E-1) to (E-3) and formula (E-5), and having a boiling point of 190° C. or less at 1 atm an organic solvent that is
contains
The polymer (Q) is at least one polymer selected from the group consisting of polyamic acids, polyamic acid esters, polyimides, and polymers having structural units derived from monomers having unsaturated bonds. Liquid crystal aligning agent.

(In formula (A), "*" indicates a bond.)

(In formula (E-1), R ⁴¹ is an alkyl group having 1 to 3 carbon atoms or R ⁴⁰ —CO— (wherein R ⁴⁰ is an alkyl group having 1 to 3 carbon atoms), and R ⁴² is a carbon an alkanediyl group having a number of 1 to 4 or —(R ⁴⁷ —O)r—R ⁴⁸ — (provided that R ⁴⁷ and R ⁴⁸ are each independently an alkanediyl group having 2 or 3 carbon atoms and r is 1 to is an integer of 4), and R ⁴³ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

(In formula (E-2), R ⁴⁴ is an alkanediyl group having 1 to 4 carbon atoms.)

(In formula (E-3), R ⁴⁵ and R ⁴⁶ are each independently an alkyl group having 1 to 8 carbon atoms. )

(In the formula (E-5), R ⁵¹ is a monovalent hydrocarbon group having 1 to 6 carbon atoms, a monovalent group in which the hydrogen atom of the hydrocarbon group having 1 to 6 carbon atoms is substituted with a hydroxyl group, or a monovalent group having —CO— between the carbon-carbon bonds of a hydrocarbon group having 2 to 6 carbon atoms, and R ⁵² is a monovalent hydrocarbon group having 1 to 6 carbon atoms.) The liquid crystal aligning agent according to claim 1, wherein the polymer (P) is a polymer having a structural unit represented by the following formula (1).

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom or a methyl group.) The liquid crystal aligning agent according to claim 2, wherein the polymer (P) further has a structural unit represented by the following formula (2).

(In formula (2), R ⁴ and R ⁵ are each independently a hydrogen atom or a methyl group, and R ³ is a monovalent organic group having 1 or more carbon atoms.) A liquid crystal alignment film formed using the liquid crystal alignment agent according to any one of claims 1 to 3 . A liquid crystal device comprising the liquid crystal alignment film according to claim 4 . A method for producing a liquid crystal aligning agent,
A step of mixing the polymer component and an organic solvent,
The polymer component is obtained by reacting a polymer (P) having a partial structure represented by the following formula (A), and a compound represented by the following formula (4) with the polymer (P). At least one selected from the group consisting of polymers and a polymer (Q) different from the polymer (P) ,
The organic solvent is at least one selected from the group consisting of compounds represented by the following formulas (E-1) to (E-3) and (E-5), and Containing a compound having a boiling point of 190 ° C. or less,
The polymer (Q) is at least one polymer selected from the group consisting of polyamic acids, polyamic acid esters, polyimides, and polymers having structural units derived from monomers having unsaturated bonds. A method for producing a liquid crystal aligning agent.

(In formula (A), "*" indicates a bond.)

(In formula (4), R ¹⁰ is a monovalent organic group having 1 or more carbon atoms, X ¹ is an oxygen atom or —NR ¹¹ — (R ¹¹ is a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms). It is a hydrocarbon group.)

(In formula (E-1), R ⁴¹ is an alkyl group having 1 to 3 carbon atoms or R ⁴⁰ —CO— (wherein R ⁴⁰ is an alkyl group having 1 to 3 carbon atoms), and R ⁴² is a carbon an alkanediyl group having a number of 1 to 4 or —(R ⁴⁷ —O)r—R ⁴⁸ — (provided that R ⁴⁷ and R ⁴⁸ are each independently an alkanediyl group having 2 or 3 carbon atoms and r is 1 to is an integer of 4), and R ⁴³ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

(In formula (E-2), R ⁴⁴ is an alkanediyl group having 1 to 4 carbon atoms.)

(In formula (E-3), R ⁴⁵ and R ⁴⁶ are each independently an alkyl group having 1 to 8 carbon atoms. )

(In the formula (E-5), R ⁵¹ is a monovalent hydrocarbon group having 1 to 6 carbon atoms, a monovalent group in which the hydrogen atom of the hydrocarbon group having 1 to 6 carbon atoms is substituted with a hydroxyl group, or a monovalent group having —CO— between the carbon-carbon bonds of a hydrocarbon group having 2 to 6 carbon atoms, and R ⁵² is a monovalent hydrocarbon group having 1 to 6 carbon atoms.) The method for producing a liquid crystal aligning agent according to claim 6 , wherein the polymer (P) is a polymer having a structural unit represented by the following formula (1).

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom or a methyl group.)