JP6841069B2 - Liquid crystal alignment agent, liquid crystal alignment film and its manufacturing method, and liquid crystal element - Google Patents

Description

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, a method for producing the same , and a liquid crystal element.

Liquid crystal elements are widely used in televisions, mobile devices, various monitors, and the like. Further, in the liquid crystal element, a liquid crystal alignment film is used to control the orientation of the liquid crystal molecules in the liquid crystal cell. Conventional methods for obtaining an organic film having a liquid crystal orientation regulating force include a method of rubbing an organic film, a method of obliquely depositing silicon oxide, a method of forming a monomolecular film having a long-chain alkyl group, and a photosensitive organic method. A method of irradiating a film with light (photoalignment method) is known.

Since the photo-alignment method can impart uniform liquid crystal orientation to a photosensitive organic film while suppressing the generation of static electricity and dust, and can also precisely control the liquid crystal orientation direction, various studies have been conducted in recent years. (See, for example, Patent Document 1). In Patent Document 1, a polyimide precursor having a cyclobutane ring structure as a main chain or a liquid crystal aligning agent containing polyimide is applied onto a substrate, and a film obtained by firing is irradiated with polarized radiation and then has a boiling point of 110 to 180. It is disclosed that a liquid crystal alignment film is obtained by contacting a film with an organic solvent at ° C., then contacting with water or a water-soluble organic solvent having a boiling point of 50 to 105 ° C., and then heat-treating at 150 ° C. or higher. There is. By performing such a film cleaning treatment and heat treatment, when the alignment ability is imparted to the film by the photoalignment method, the afterimage due to the AC drive generated in the liquid crystal display element of the IPS drive method or the FFS drive method is suppressed. It is disclosed to do.

International Publication No. 2014/084362

However, since the method described in Patent Document 1 requires a step of cleaning and heating the film, there is a concern that the number of steps will increase when manufacturing the liquid crystal element, resulting in high cost and complexity. To. In recent years, large-screen, high-definition LCD TVs have become the mainstream, and small display terminals such as smartphones and tablet PCs have become widespread, and the demand for high-definition and low-cost LCD panels is increasing. .. Therefore, it has become more important than ever to develop a technology capable of manufacturing a liquid crystal element having good various characteristics related to the display quality of the liquid crystal element, such as liquid crystal orientation and afterimage characteristics, at the lowest possible cost.

Liquid crystal elements are currently applied to a wide range of devices and applications, from large-screen liquid crystal televisions to small display devices such as smartphones and tablet PCs. In addition, with the increasing versatility of liquid crystal elements, they can be placed or installed in places where high temperatures can occur, such as inside cars and outdoors, or they can be driven for a longer time than before, under harsher high-temperature environments. Expected to be used. Therefore, the liquid crystal element is required to have high reliability for heat resistance. However, when a liquid crystal alignment film is produced by a photoalignment treatment using a liquid crystal alignment agent containing a polyimide-based polymer having a cyclobutane ring structure in the main chain, it is caused by the decomposition products generated by light irradiation of the coating film. When the obtained liquid crystal element is exposed to a high temperature environment for a long time, minute bright spots are likely to occur, and there is a concern that the reliability of heat resistance is inferior.

The present invention has been made in view of the above circumstances, and when the photoalignment method is applied, the heat resistance is good and good even if no special treatment is performed after irradiating the liquid crystal with light. One object of the present invention is to provide a liquid crystal alignment agent capable of obtaining a liquid crystal element exhibiting excellent liquid crystal orientation and afterimage characteristics.

As a result of diligent studies to achieve the above-mentioned problems of the prior art, the present inventor has found that the above-mentioned problems can be solved by using a polymer having a specific partial structure as an alignment film material. The present invention has been completed. Specifically, the following means are provided.

（式（１）中、Ｒ^１は置換基を有していても良いシクロブタン環構造を有する４価の有機基であり、Ｒ^２は２価の有機基である。Ｘ^１及びＸ^２は、それぞれ独立に水酸基又は炭素数１〜４０の１価の有機基である。ただし、Ｘ^１及びＸ^２の少なくともいずれかは反応性基を有する１価の有機基である。）
＜２＞ 上記＜１＞の液晶配向剤を用いて塗膜を形成し、該塗膜に光照射して液晶配向能を付与する、液晶配向膜の製造方法。
＜３＞ 上記＜１＞の液晶配向剤を用いて形成された液晶配向膜。
＜４＞ 上記＜３＞に記載の液晶配向膜を備える液晶素子。
＜５＞ 上記式（１）で表される部分構造を有する重合体。
＜６＞ 下記式（１−１）若しくは下記式（１−２）で表される化合物又はその塩。

（式（１−１）及び式（１−２）中、Ｘ^１１及びＸ^１２は、それぞれ独立に水素原子又は炭素数１〜４０の１価の有機基である。ただし、Ｘ^１１及びＸ^１２の少なくともいずれかは、反応性基を有する１価の有機基である。Ｒ^３は、それぞれ独立に、水素原子、フッ素原子、塩素原子、臭素原子、又は置換基を有してもよい炭素数１〜１０の１価の脂肪族基である。Ｘは、水酸基、塩素原子、臭素原子、及び下記式（４−１）〜式（４−６）のそれぞれで表される構造よりなる群から選ばれる１種である。）

（式（４−１）〜式（４−６）中、「＊」は結合手であることを示す。） <1> A liquid crystal alignment agent containing a polymer (P) having a partial structure represented by the following formula (1).

(In the formula (1), R ¹ is a tetravalent organic group having a cyclobutane ring structure which may have a substituent, and R ² is a divalent organic group. X ¹ and X ² are divalent organic groups. Each is independently a hydroxyl group or a monovalent organic group having 1 to 40 carbon atoms. However, ^{at least one of X 1} and X ² is a monovalent organic group having a reactive group.)
<2> A method for producing a liquid crystal alignment film, which forms a coating film using the liquid crystal alignment agent of <1> above, and irradiates the coating film with light to impart liquid crystal alignment ability.
<3> A liquid crystal alignment film formed by using the liquid crystal alignment agent of <1> above.
<4> A liquid crystal element provided with the liquid crystal alignment film according to <3> above.
<5> A polymer having a partial structure represented by the above formula (1).
<6> A compound represented by the following formula (1-1) or the following formula (1-2) or a salt thereof.

(In formulas (1-1) and (1-2), X ¹¹ and X ¹² are independently hydrogen atoms or monovalent organic groups having 1 to 40 carbon atoms, respectively. However, X ¹¹ and X ¹² At least one of the above is a monovalent organic group having a reactive group. R ³ has the number of carbon atoms which may independently have a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, or a substituent. It is a monovalent aliphatic group of 1 to 10. X is composed of a hydroxyl group, a chlorine atom, a bromine atom, and a group consisting of structures represented by the following formulas (4-1) to (4-6). It is one of the choices.)

(In equations (4-1) to (4-6), "*" indicates a bond.)

According to the liquid crystal alignment agent of the present disclosure, it is possible to obtain a liquid crystal element having high heat resistance and good liquid crystal orientation and afterimage characteristics without performing special treatment such as cleaning or heating of the film after irradiation with radiation. it can. That is, when the alignment ability is imparted to the film by the photo-alignment method, a liquid crystal element having high heat resistance, little afterimage, and good liquid crystal orientation can be obtained in as few steps as possible.

Hereinafter, the components to be blended in the liquid crystal alignment agent of the present disclosure and other components to be optionally blended will be described.

（式（ｒ−１）中、Ｒ^３は、それぞれ独立に、水素原子、フッ素原子、塩素原子、臭素原子、又は置換基を有してもよい炭素数１〜１０の１価の脂肪族基である。） ≪Polymer (P) ≫
The liquid crystal alignment agent of the present disclosure contains a polymer (P) having a partial structure represented by the above formula (1). In the above formula (1), R ¹ is a tetravalent group derived from a tetracarboxylic acid derivative having a cyclobutane ring structure, and preferably has a partial structure represented by the following formula (r-1). That is, the polymer (P) preferably has at least one of a partial structure represented by the following formula (1-A) and a partial structure represented by the following formula (1-B).

(In the formula (r-1), R ³ is a monovalent aliphatic group having 1 to 10 carbon atoms which may independently have a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, or a substituent. Is.)

（式（１−Ａ）及び式（１−Ｂ）中、Ｒ^２、Ｘ^１及びＸ^２は、それぞれ上記式（１）中のＲ^２、Ｘ^１及びＸ^２と同義である。Ｒ^３は、上記式（ｒ−１）中のＲ^３と同義である。）

(In the formula (1-A) and formula ^(1-B), R 2, ^{X 1} and ^{X 2} are each ^R 2, ^{X 1} and ^{X 2} as synonymous .R ³ in the formula (1) , Synonymous with ^{R 3} in the above equation (r-1).)

In the above formula (r-1), the ^{monovalent aliphatic group having 1 to 10 carbon atoms which may have a substituent of R 3} is an alkyl group having 1 to 10 carbon atoms, a fluorine-containing alkyl group, and an alkoxy group. , fluorine-containing alkoxy group, or "-COOR ^20" (wherein ^{R 20} is an alkyl group having 1 to 10 carbon atoms, a fluorine-containing alkyl group, an alkoxy group or a fluorine-containing alkoxy group.) is preferably. Incidentally, four R ³ in the formula may be the same as each other or may be different.
R ² is a divalent group derived from a diamine compound, and examples thereof include a divalent group obtained by removing two primary amino groups from a conventionally known diamine compound.

Examples of the monovalent organic group having 1 to 40 carbon atoms of X ¹ and X ² include a monovalent hydrocarbon group having 1 to 40 carbon atoms and a methylene group of the hydrocarbon group being −O−, −S—,. -CO-, -COO-, -COS-, -NR ^3- , -CO-NR ^3- , -Si (R ³ ) _2- (However, R ³ is a hydrogen atom or a monovalent group having 1 to 12 carbon atoms. The hydrogen atom bonded to the carbon atom of the monovalent group A, the monovalent group A, or the monovalent group A, which is replaced with -N = N-, -SO _{2-, etc.} At least one of the halogen atoms (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), hydroxyl group, alkoxy group, nitro group, amino group, mercapto group, nitroso group, alkylsilyl group, alkoxysilyl group, silanol group, Examples thereof include a monovalent group substituted with a sulfino group, a phosphino group, a carboxyl group, a cyano group, a sulfo group, an acyl group and the like, a monovalent group having a heterocycle, and the like. However, ^{at least one of X 1} and X ² is a monovalent organic group having a reactive group.

Here, the term "hydrocarbon group" as used herein means to include a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The "chain hydrocarbon group" means a linear hydrocarbon group and a branched hydrocarbon group which do not contain a cyclic structure in the main chain and are composed only of a chain structure. However, it may be saturated or unsaturated. The "alicyclic hydrocarbon group" means a hydrocarbon group containing only the alicyclic hydrocarbon structure as the ring structure and not containing the aromatic ring structure. However, it does not have to be composed only of the alicyclic hydrocarbon structure, and some of them have a chain structure. The "aromatic hydrocarbon group" means a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it does not have to be composed of only an aromatic ring structure, and a chain structure or an alicyclic hydrocarbon structure may be included in a part thereof. "Aliphatic group" means a chain hydrocarbon group and an alicyclic hydrocarbon group.

（式（５−１）〜式（５−１０）中、Ｒ^４１は、置換基を有していてもよい炭素数１〜６の２価の脂肪族基であり、Ｒ^５は、それぞれ独立に、水素原子、又は置換基を有していてもよい炭素数１〜６の１価の脂肪族基である。ただし、Ｒ^４１及びＲ^５のうち任意の２つの脂肪族基同士が結合して環構造を形成していてもよい。式（５−１）、式（５−９）中の複数のＲ^５は、互いに同じでも異なっていてもよい。「＊」は結合手であることを示す。） The ^{reactive groups possessed by at least one of X 1} and X ² are shared between the reactive groups and / or the maleimide compound in the presence of at least one of heat, light, acid, base and radical. It is preferably a group that forms a bond. The reactive group is preferably a group that reacts with at least one of heat and light. Specific examples of the reactive group include structures represented by the following formulas (5-1) to (5-10), (meth) acryloyloxy group, styryl group, vinylphenyl group, and (meth) acrylamide. Examples include a group, a vinyloxy group (CH ₂ = CH—O−), a group represented by each of the following formulas (p-1) and (p-2), and the like. The vinylphenyl group and the vinyloxy group are examples of structures represented by the following formula (5-1).

(In formulas (5-1) to (5-10), R ⁴¹ is a divalent aliphatic group having 1 to 6 carbon atoms which may have a substituent, and R ⁵ is independent of each other. Is a monovalent aliphatic group having 1 to 6 carbon atoms which may have a hydrogen atom or a substituent. However, ^{any two aliphatic groups of R 41} and R ⁵ are bonded to each other. Te may form a ring structure. equation (5-1), a plurality of R ⁵ in the formula (5-9) may be the same or different from each other. "*" it is a bond Shows.)

（式（ｐ−１）中、Ｘ^５は、酸素原子又は−ＮＨ−である。「＊」は結合手を示す。）

(In formula (p-1), X ⁵ is an oxygen atom or -NH-. "*" Indicates a bond.)

In the above formula (5-1), the divalent aliphatic group having 1 to 6 carbon atoms of ^{R 41 is preferably an alkanediyl group or an arcendyl group.} Examples of the substituent that R ⁴¹ may have include a halogen atom and an alkoxy group. It is preferred monovalent aliphatic group having 1 to 6 carbon atoms R ⁵ is an alkyl or alkenyl group.
In the above formulas (5-2) to (5-10), the divalent aliphatic group having 1 to 6 carbon atoms of ^{R 41 is preferably an alkanediyl group.} The description of the above formula (5-1) is applied to the substituent that ^{R 41 may have.} Monovalent aliphatic group having 1 to 6 carbon atoms for R ⁵ is preferably an alkyl group. R ⁵ in the formula (5-5), it is particularly preferred in view of reactivity is a hydrogen atom or a methyl group.

The reactive group is represented by each of the above formulas (5-1) to (5-10) among the above from the viewpoint of obtaining a liquid crystal element having excellent liquid crystal orientation, AC afterimage characteristics and heat resistance. It is preferably at least one selected from the group consisting of the structure and the (meth) acryloyloxy group, and the above formulas (5-1), formula (5-2), formulas (5-4) to (5-6). ) And at least one selected from the group consisting of (meth) acryloyloxy groups. In addition, in this specification, "(meth) acrylic" means acrylic and methacrylic.
The reactive group exemplified above may be directly bonded to the carbonyl group in the formula (1), or may be bonded via a divalent linking group. The divalent linking group includes, for example, an oxygen atom, an alkanediyl group having 1 to 20 carbon atoms, and a divalent group having -O-, -CO-, -COO-, etc. between carbon-carbon bonds of the alkanediyl group. The basis of.

（式（２−１）〜式（２−１０）中、Ｒ^４は、置換基を有していてもよい炭素数１〜６の２価の脂肪族基であり、Ｒ^５は、それぞれ独立に、水素原子、又は置換基を有していてもよい炭素数１〜６の１価の脂肪族基である。ただし、Ｒ^４及びＲ^５のうち任意の２つの脂肪族基同士が結合して環構造を形成していてもよい。式（２−１）、式（２−９）中の複数のＲ^５は、互いに同じでも異なっていてもよい。「＊」は結合手であることを示す。） X ¹ and X ² are at least one selected from the group consisting of structures represented by the following formulas (2-1) to (2-10) and (meth) acryloyloxy groups. It is preferable that the group consists of the structures represented by the following formulas (2-1), formula (2-2), formulas (2-4) to (2-6) and (meth) acryloyloxy groups. It is more preferable that it is one selected. ^{Regarding the explanation of R 4} and R ^{5 in} the following formulas (2-1) to (2-10), ^{refer to R 41} and R ^{5 in} the above formulas (5-1) to (5-10). Each description applies.

(In formulas (2-1) to (2-10), R ⁴ is a divalent aliphatic group having 1 to 6 carbon atoms which may have a substituent, and R ⁵ is independent of each other. a hydrogen atom or a monovalent aliphatic group having 1 to 6 carbon atoms which may have a substituent. However, any two aliphatic groups bonded to each other among the R ⁴ and R ⁵ Te may form a ring structure. equation (2-1), a plurality of R ⁵ in the formula (2-9) may be the same or different from each other. "*" it is a bond Shows.)

[Synthesis of polymer (P)]
The method for synthesizing the polymer (P) is not particularly limited, but as a preferable method, it is also referred to as a compound represented by each of the above formula (1-1) and the above formula (1-2) (hereinafter, also referred to as “specific acid derivative”). A method of reacting a tetracarboxylic acid derivative containing at least one of the above) with a diamine compound can be mentioned.

In the present specification, the "tetracarboxylic acid derivative" is a tetracarboxylic acid dianhydride in which four carboxyl groups of the tetracarboxylic acid are dehydrated and condensed, and at least one of the four carboxyl groups of the tetracarboxylic acid. Includes compounds in which is replaced with "-COX ³ " (where X ³ is a halogen atom or a monovalent organic group with 1-40 carbon atoms). Specifically, in addition to tetracarboxylic acid dianhydride, for example, a compound in which one or two of the four carboxyl groups of tetracarboxylic acid are esterified and the rest are carboxyl groups, tetracarboxylic acid. One or two of the four carboxyl groups possessed are esterified, and the remaining carboxyl groups are represented by a desorbing group (for example, a halogen atom, which is represented by the above formulas (4-1) to (4-6), respectively. Examples thereof include a compound into which a (structure, etc.) is introduced or a salt thereof.

The formula (1-1), the formula (1-2), preferred examples of ^{R 3} include a description of the formula (r-1) is applied. X ¹¹ and X ¹² are at least one selected from the group consisting of the structures represented by the above formulas (2-1) to (2-10) and (meth) acryloyloxy groups. Is preferable. When X ¹¹ and X ¹² are groups having no reactive group, X ¹¹ and X ¹² are preferably hydrogen atoms or alkyl groups having 1 to 10 carbon atoms.
X is preferably a hydroxyl group or a chlorine atom. When X is a hydroxyl group, the specific acid dianhydride is a tetracarboxylic dianhydride, and when X is a chlorine atom or a bromine atom, the specific acid dianhydride is a tetracarboxylic dianester dihalide.

[Tetracarboxylic acid derivative]
(Specific acid derivative)
The specific acid derivative is, for example, a reactive group with a tetracarboxylic dianhydride containing [1] tetracarboxylic dianhydride having a cyclobutane ring structure (hereinafter, also referred to as “specific tetracarboxylic dianhydride”). (Hereinafter, also referred to as "reactive group-containing compound (E)"), [2] a tetracarboxylic dianhydride containing a specific tetracarboxylic dianhydride and a reactive group-containing compound. It can be obtained by a method of reacting with (E) to obtain a tetracarboxylic dianester and then reacting with the above-mentioned compound having a desorbing group (for example, a halogenating agent).

（式（４）中、Ａ^１は、シクロブタン環構造を有する４価の有機基である。） -Specific tetracarboxylic dianhydride The specific tetracarboxylic dianhydride is not particularly limited as long as it has a cyclobutane ring structure, and is specifically represented by the following formula (4).

(In formula (4), A ¹ is a tetravalent organic group having a cyclobutane ring structure.)

In the above formula (4), A ¹ preferably has a structure represented by the above formula (r-1). Specific examples of the specific tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1-methyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, and the like. 1,3-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, 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, formulas (T-1-1) to Examples thereof include compounds represented by each of (T-1-16).

Of these, the specific tetracarboxylic dianhydrides are 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride. , 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride is particularly preferable. As the specific tetracarboxylic dianhydride, one type may be used alone or two or more types may be used in combination.

（式（３−１）中、Ａ^２は反応性基であり、Ｒ^１１は単結合又は（ｋ＋１）価の炭化水素基である。ｋは１〜３の整数である。） -Reactive group-containing compound (E)
The reactive group-containing compound (E) is not particularly limited as long as it has a reactive group and a functional group that reacts with an acid dianhydride group, but is preferably represented by the following formula (3-1). Compound.

(In formula (3-1), A ² is a reactive group and R ¹¹ is a single bond or (k + 1) -valent hydrocarbon group. K is an integer of 1-3.)

In the above formula (3-1), ^{examples of the (k + 1) -valent hydrocarbon group of R 11} include a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group. k is preferably 1, and ^{as a specific example of R 11} in this case, as a divalent chain hydrocarbon group, for example, a methylene group, an ethylene group, a propanediyl group, a butanjiyl group, a pentandiyl group, or a hexanediyl group. , Heptangiyl group, octanediyl group, nonandiyl group, decandyl group and the like, and these may be linear or branched. The ^{divalent alicyclic hydrocarbon group of R 11} is a cyclohexylene group, −R ^c − (CH ₂ ) _n − (where R ^c is a cyclohexylene group and n is an integer of 1 to 5). Examples of the divalent aromatic hydrocarbon group include a phenylene group, a biphenylene group, _{and −Ph- (CH 2} ) _n − (where Ph is a phenylene group and n is an integer of 1 to 5). ) And so on.
A ² is an explanatory description and preferred examples of the reactive group of the above formula (1) is applied.

Specific examples of the compound represented by the above formula (3-1) include compounds represented by each of the following formulas (3-1-1) to (3-1-16). The reactive group-containing compound (E) may be used alone or in combination of two or more.

-Reaction between tetracarboxylic dianhydride and reactive group-containing compound (E) The reaction between tetracarboxylic dianhydride and reactive group-containing compound (E) may be carried out in an organic solvent, if necessary. it can. The organic solvent used is not particularly limited as long as it is inert to the tetracarboxylic acid dianhydride and the reactive group-containing compound (E), but for example, ketones such as acetone and methyl ethyl ketone; hydrocarbons such as hexane, heptane and toluene. Hydrogen; halogen-based hydrocarbons such as chloroform and 1,2-dichloroethane; ethers such as tetrahydrofuran, diethyl ether and 1,4-dioxane; nitrile compounds such as acetonitrile and propionitrile, and the like. In addition, these organic solvents can be used individually by 1 type or in combination of 2 or more types.

The ratio of the reactive group-containing compound (E) to be used is usually 2 to 100 mol, preferably 2 to 40 mol, based on 1 mol of the tetracarboxylic dianhydride. The reaction temperature at this time can be appropriately set according to the type of the reactive group-containing compound (E) to be used, but is preferably −20 ° C. to 150 ° C., preferably 0 to 100 ° C. More preferred. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours. Further, after the reaction, reprecipitation may be performed if necessary. The obtained precipitate can then be washed and dried, if necessary, to obtain the target compound (tetracarboxylic dianester).

In the above method [2], when the tetracarboxylic dianester obtained in the above reaction is reacted with an appropriate halogenating agent such as thionyl chloride, it is preferably carried out in an organic solvent. As for the conditions such as the organic solvent, the reaction temperature, and the reaction time, the description of the reaction conditions of the tetracarboxylic dianhydride and the reactive group-containing compound (E) is applied.

-Other Acid Derivatives When synthesizing the polymer (P), only a specific acid derivative may be used as the tetracarboxylic acid derivative, but together with the specific acid derivative, a tetracarboxylic acid derivative different from the specific acid derivative (hereinafter, "" Other acid derivatives ”) may be used in combination. Examples of other acid derivatives include a tetracarboxylic dianester having no reactive group, a tetracarboxylic dianester dihalide having no reactive group, and a tetracarboxylic dianhydride having no cyclobutane ring structure (hereinafter,). , "Other tetracarboxylic dianhydride") and the reaction product of the reactive group-containing compound (E), tetracarboxylic dianhydride and the like.

The other tetracarboxylic dianhydride is not particularly limited. As a specific example, as the aliphatic tetracarboxylic dianhydride, for example, ethylenediaminetetraacetic acid dianhydride;

As the alicyclic tetracarboxylic acid dianhydride, for example, 2,3,5-tricarboxycyclopentylacetate dianhydride, 5- (2,5-dioxo tetrahydrofuran-3-yl) -3a, 4,5,9b- Tetrahydronaphtho [1,2-c] furan-1,3-dione, 5- (2,5-dioxo tetrahydrofuran-3-yl) -8-methyl-3a, 4,5,9b-tetrahydronaphtho [1, 2-c] Fran-1,3-dione, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 3,5,6 -Tricarboxy-2-carboxymethyl norbornan-2: 3,5: 6-dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8- Dianhydride, cyclohexanetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic acid dianhydride, etc .; as aromatic tetracarboxylic acid dianhydride, for example, pyromellitic acid dianhydride, 4,4'-(hexafluoroisopropi). Liden) Diphthalic acid anhydride, p-phenylenebis (trimeritic acid monoester anhydride), ethylene glycol bis (anhydrotrimeritate), 1,3-propylene glycolbis (anhydrotrimeritate), etc .; In addition, the tetracarboxylic dianhydride described in JP-A-2010-97188 can be used. In the synthesis of the polymer (P), one type of other tetracarboxylic dianhydride may be used alone or in combination of two or more types.

In synthesizing the polymer (P), the ratio of the specific acid derivative used shall be 10 mol% or more with respect to the total amount of the tetracarboxylic acid derivative used in the synthesis from the viewpoint of sufficiently obtaining the effects of the present disclosure. Is preferable. It is more preferably 30 mol% or more, still more preferably 50 mol% or more. As the specific acid derivative and the other acid derivative, one type may be used alone, or two or more types may be used in combination.

[Diamine compound]
The diamine compound used for the synthesis of the polymer (P) is not particularly limited, and various diamine compounds can be used. Specific examples thereof include, for example, metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, hexamethylenediamine and the like as aliphatic diamines; and for example, 1,4-diaminocyclohexane, 4, as alicyclic diamines. 4'-methylenebis (cyclohexylamine) etc .;

（式（Ｅ−１）中、Ｘ^I及びＸ^IIは、それぞれ独立に、単結合、−Ｏ−、−ＣＯＯ−又は−ＯＣＯ−であり、Ｒ^Ｉは炭素数１〜３のアルカンジイル基であり、Ｒ^ＩＩは単結合又は炭素数１〜３のアルカンジイル基であり、ａは０又は１であり、ｂは０〜２の整数であり、ｃは１〜２０の整数であり、ｄは０又は１である。ただし、ａ及びｂが同時に０になることはない。）
で表される化合物などの側鎖型ジアミン：
ｐ−フェニレンジアミン、４，４’−ジアミノジフェニルメタン、４，４’−ジアミノジフェニルエタン、４，４’−ジアミノジフェニルスルフィド、４−アミノフェニル−４’−アミノベンゾエート、４，４’−ジアミノアゾベンゼン、３，５−ジアミノ安息香酸、１，５−ビス（４−アミノフェノキシ）ペンタン、ビス［２−（４−アミノフェニル）エチル］ヘキサン二酸、ビス（４−アミノフェニル）アミン、Ｎ，Ｎ−ビス（４−アミノフェニル）メチルアミン、２，６−ジアミノピリジン、１，４−ビス−（４−アミノフェニル）−ピペラジン、Ｎ，Ｎ’−ビス（４−アミノフェニル）−ベンジジン、２，２’−ジメチル−４，４’−ジアミノビフェニル、２，２’−ビス（トリフルオロメチル）−４，４’−ジアミノビフェニル、４，４’−ジアミノジフェニルエーテル、２，２−ビス［４−（４−アミノフェノキシ）フェニル］プロパン、４，４’−（フェニレンジイソプロピリデン）ビスアニリン、１，４−ビス（４−アミノフェノキシ）ベンゼン、４−（４−アミノフェノキシカルボニル）−１−（４−アミノフェニル）ピペリジン、４，４’−［４，４’−プロパン−１，３−ジイルビス（ピペリジン−１，４−ジイル）］ジアニリンなどの非側鎖型ジアミンを；
ジアミノオルガノシロキサンとして、例えば、１，３−ビス（３−アミノプロピル）−テトラメチルジシロキサンなどを；それぞれ挙げることができるほか、特開２０１０−９７１８８号公報に記載のジアミンを用いることができる。また、重合体（Ｐ）の合成に使用するジアミン化合物は、上記反応性基を有する基を置換基として有していてもよい。 Examples of aromatic diamines include dodecanoxidiaminobenzene, hexadecanoxidiaminobenzene, octadecanoxidiaminobenzene, cholestanyloxydiaminobenzene, cholesteryloxydiaminobenzene, cholestanyl diaminobenzoate, cholesteryl diaminobenzoate, and diaminobenzoic acid. Ranostanyl, 3,6-bis (4-aminobenzoyloxy) cholesterol, 3,6-bis (4-aminophenoxy) cholesterol, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-butyl Cyclohexane, 2,5-diamino-N, N-diallylaniline, the following formula (E-1)

(In the formula (E-1), X ^I and X ^II is independently a single bond, -O -, - COO- or a -OCO-, ^{R I} is alkanediyl group having 1 to 3 carbon atoms Yes, R ^II is a single bond or an alkanediyl group with 1-3 carbon atoms, a is 0 or 1, b is an integer 0-2, c is an integer 1-20, d is It is 0 or 1. However, a and b cannot be 0 at the same time.)
Side chain diamines such as compounds represented by:
p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylsulfide, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-Diaminobenzoic acid, 1,5-bis (4-aminophenoxy) pentane, bis [2- (4-aminophenyl) ethyl] hexanedioic acid, bis (4-aminophenyl) amine, N, N- Bis (4-aminophenyl) methylamine, 2,6-diaminopyridine, 1,4-bis- (4-aminophenyl) -piperazin, N, N'-bis (4-aminophenyl) -benzidine, 2,2 '-Dimethyl-4,4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 2,2-bis [4- (4) -Aminophenoxy) phenyl] propane, 4,4'-(phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4- (4-aminophenoxycarbonyl) -1- (4-amino) Non-side chain diamines such as phenyl) piperidine, 4,4'-[4,4'-propane-1,3-diylbis (piperidin-1,4-diyl)] dianiline;
Examples of the diaminoorganosiloxane include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane; and the diamine described in JP-A-2010-97188 can be used. Further, the diamine compound used for the synthesis of the polymer (P) may have the above-mentioned reactive group as a substituent.

The diamine compound used in the synthesis of the polymer (P) preferably contains at least one of p-phenylenediamine, 4,4'-diaminodiphenylmethane and 4,4'-diaminodiphenylethane. In the synthesis of the polymer (P), one diamine compound may be used alone or two or more diamine compounds may be used in combination.

[Reaction between tetracarboxylic acid derivative and diamine compound]
The reaction between the tetracarboxylic acid derivative and the diamine compound can be carried out by appropriately combining the conventional methods of organic chemistry depending on the tetracarboxylic acid derivative used.

For example, when the tetracarboxylic acid derivative is a tetracarboxylic acid diester, a method of reacting the tetracarboxylic acid diester and the diamine compound in an organic solvent in the presence of a suitable dehydration catalyst can be used. Examples of the dehydration catalyst used in the reaction include 4- (4,6-dimethoxy-1,3,5-triazine-2-yl) -4-methylmorpholinium halide, carbonylimidazole, dicyclohexylcarbodiimide, and phosphorus-based condensing agent. And so on. The ratio of these dehydration catalysts to be used is preferably 2 to 3 mol, more preferably 2 to 2.5 mol, based on 1 mol of the tetracarboxylic diandies.

When the tetracarboxylic acid derivative is a tetracarboxylic acid diester dihalide, a method of reacting the tetracarboxylic acid diester dihalide with the diamine compound, preferably in an organic solvent in the presence of an appropriate base can be used. .. Examples of the base used in the reaction include tertiary amines such as pyridine and triethylamine; alkali metals such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium and potassium. The ratio of the base used is preferably 2 to 4 mol, more preferably 2 to 3 mol, with respect to 1 mol of the diamine compound. The reaction between the tetracarboxylic dianester dihalide and the diamine compound may be carried out in the presence of Lewis acid for the purpose of accelerating the progress of the reaction. Examples of Lewis acid include lithium halide such as lithium chloride.

In the reaction between the tetracarboxylic acid derivative and the diamine compound, the ratio of the tetracarboxylic acid derivative and the diamine compound used in the reaction is involved in the reaction of the tetracarboxylic acid derivative with respect to one amino group equivalent of the diamine compound. It is preferable that the amount of the group "-COX ⁴ (X ⁴ is a hydroxyl group or a leaving group)" is 0.2 to 2 equivalents. The reaction temperature is preferably −30 ° C. to 150 ° C., and the reaction time is preferably 0.1 to 48 hours.

Examples of the organic solvent used in the reaction include an aprotic polar solvent, a ketone, an ester, an ether, a halogenated hydrocarbon, and a hydrocarbon. Among these organic solvents, one or more selected from the group consisting of aprotic polar solvents (organic solvents of the first group), or one or more selected from the organic solvents of the first group, and ketones. It is preferable to use a mixture with one or more selected from the group consisting of esters, ethers, halogenated hydrocarbons and hydrocarbons (organic solvents of the second group). In the latter case, the ratio of the organic solvent used in the second group is preferably 50% by mass or less, more preferably 40% by mass, based on the total amount of the organic solvent in the first group and the organic solvent in the second group. It is less than or equal to, more preferably 30% by mass or less.

Particularly preferred organic solvents are N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol. It is preferable to use one or more selected from the group consisting of and halogenated phenol as a solvent, or to use a mixture of one or more of these and another organic solvent in the above ratio range. The amount of the organic solvent used (a) is preferably such that the total amount (b) of the monomers used in the reaction is 0.1 to 50% by mass with respect to the total amount (a + b) of the reaction solution.

(Terminal modifier)
By using a terminal modifier having a functional group together with the tetracarboxylic acid derivative and the diamine compound in the synthesis of the polymer (P), the partial structure represented by the above formula (1) can be obtained as the polymer (P). A polymer having a functional group at the end of the polymer can be obtained. In this case, when the polymer (Q) described later is contained in the liquid crystal alignment agent together with the polymer (P), the coatability of the liquid crystal alignment agent can be further improved, which is preferable.

Examples of the terminal modifier include acid monoanhydride, monocarbonyl chloride, monoamine compound, monoisocyanate compound and the like. Examples of the functional group contained in the terminal modifier include the above-mentioned reactive group, thiol group, protected amino group and the like.
Specific examples of such terminal modifiers include (meth) acryloyl chloride, 2-furancarbonyl chloride, furfurylamine, 2-aminoethanethiol, 3-aminopropanethiol, N- (tert-butoxycarbonyl) -1, Examples thereof include 2-diaminoethane and N- (tert-butoxycarbonyl) -1,3-diaminopropane. The terminal modifier may be used alone or in combination of two or more.
In the above synthesis, the ratio of the terminal modifier used is preferably 20 parts or less, more preferably 0.001 to 10 parts, based on 100 parts by mole of the total diamine compound used.

The polymer (P) is a reaction product of a diamine compound and a tetracarboxylic acid derivative containing at least one of the compounds represented by the above formulas (1-1) and (1-2). This reaction product may be a polymer having only a structural unit derived from a tetracarboxylic acid derivative and a structural unit derived from a diamine compound, and the structural unit derived from the tetracarboxylic acid derivative and the structure derived from the diamine compound. It may further have other substructures different from the unit. Examples of other partial structures include partial structures derived from the terminal modifier.

As described above, a reaction solution obtained by dissolving the polymer (P) which is a polyamic acid ester is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal alignment agent, or the polyamic acid ester contained in the reaction solution may be isolated and then used for the preparation of the liquid crystal alignment agent. The polyamic acid ester may have only an amic acid ester structure, or may be a partial esterified product in which an amic acid structure and an amic acid ester structure coexist. The method for synthesizing the polyamic acid ester is not limited to the above, and can be obtained, for example, by reacting the polyamic acid with an alcohol having a reactive group or an alkyl halide.

The polymer (P) obtained as described above preferably has a solution viscosity of 20 to 1,800 mPa · s, preferably 50 to 1, when a solution having a concentration of 15% by mass is used. It is more preferable that the solution has a viscosity of 500 mPa · s. The solution viscosity (mPa · s) of the polymer (P) is 15% by mass at a concentration prepared by using a good solvent of the polymer (P) (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). It is a value measured at 25 ° C. with an E-type rotational viscometer for the polymer solution.

The polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the polymer (P) is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. 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 7 or less, more preferably 5 or less. Within such a molecular weight range, good orientation and stability of the liquid crystal device can be ensured.

When a film is formed using a liquid crystal alignment agent containing a polymer (P), when a liquid crystal alignment agent containing only a polymer having no partial structure represented by the above formula (1) as a polymer component is used. In comparison with, there is an advantage that the generation of decomposition products due to the photo-alignment treatment can be suppressed. It is thought that the cyclobutane ring in the main chain is decomposed by the reverse reaction of [2 + 2] and anisotropy is given to the membrane by lowering the molecular weight. It is presumed that the decomposition products that are substantially generated can be bound to the components in the membrane, and the generation of decomposition products can be reduced. However, this is only speculation and does not limit the content of this disclosure in any way.

≪Other ingredients≫
<Polymer (Q)>
The liquid crystal alignment agent of the present disclosure may contain only the polymer (P) as a polymer component, but at least one polymer selected from the group consisting of polyamic acid and polyimide together with the polymer (P) ( It is good that it contains Q). When a coating film is formed on a substrate using a liquid crystal alignment agent containing a polymer (P) and a polymer (Q), the polymer (P) is unevenly distributed on the outer layer of the coating film due to the difference in surface energy. It is presumed that this makes it possible to further improve the liquid crystal orientation and AC afterimage characteristics.

(Polyamic acid)
The polyamic acid as the polymer (Q) can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine compound. Examples of the tetracarboxylic dianhydride and the diamine compound used in the reaction include the tetracarboxylic dianhydride and the diamine compound exemplified in the description of the polymer (P).

The ratio of the tetracarboxylic dianhydride and the diamine compound used in the polyamic acid synthesis reaction was 0. The acid anhydride group of the tetracarboxylic dianhydride was 0. A ratio of 2 to 2 equivalents is preferable, and a ratio of 0.3 to 1.2 equivalents is more preferable. The polyamic acid synthesis reaction 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 to 24 hours. When a polyamic acid is contained as the polymer (Q), it is preferable in that the printability can be further improved while obtaining the effect of blending the polymer (P).

(Polyimide)
The polyimide as the polymer (Q) can be obtained, for example, by dehydrating and ring-closing the polyamic acid synthesized as described above to imidize it. The polyimide may be a completely imidized product in which all of the amic acid structure possessed by its precursor polyamic acid is dehydrated and ring-closed, or only a part of the amic acid structure is dehydrated and ring-closed, and the amic acid structure and imide It may be a partially imidized product in which a ring structure coexists. The polyimide used for preparing the liquid crystal alignment agent preferably has an imidization ratio of 20% or more, more preferably 30 to 99%, and even more preferably 40 to 99%. This imidization ratio is expressed as a percentage of the ratio of the number of imide ring structures to the total of the number of amic acid structures and the number of imide ring structures of polyimide. Here, a part of the imide ring may be an isoimide ring.

The dehydration ring closure of the polyamic acid is preferably carried out by a method of heating the polyamic acid, or by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating as necessary. .. Of these, the latter method is preferable.

In the method of adding a dehydrating agent and a dehydration ring-closing catalyst to a solution of polyamic acid, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride can be used as the dehydrating agent. The amount of the dehydrating agent used is preferably 0.01 to 20 mol with respect to 1 mol of the amic acid structure of the polyamic acid. As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collagen, lutidine, and triethylamine can be used. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 mol with respect to 1 mol of the dehydrating agent used. Examples of the organic solvent used in the dehydration ring closure reaction include organic solvents exemplified as compounds used in the reaction of tetracarboxylic diandies and diamines. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C., and the reaction time is preferably 1.0 to 120 hours. When polyimide is contained as the polymer (Q), it is preferable in that it is possible to further improve the electrical characteristics while obtaining the effect of blending the polymer (P).

The polymer (Q) preferably has a solution viscosity of 20 to 1,800 mPa · s when a solution having a concentration of 15% by mass is used, and has a solution viscosity of 50 to 1,500 mPa · s. It is more preferable to have. The solution viscosity (mPa · s) of the polymer (Q) is 15% by mass at a concentration prepared by using a good solvent of the polymer (Q) (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). It is a value measured at 25 ° C. with an E-type rotational viscometer for the polymer solution.

The polystyrene-equivalent weight average molecular weight (Mw) of the polymer (Q) measured by GPC is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. 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 7 or less, more preferably 5 or less.

When the liquid crystal aligning agent of the present disclosure contains a polymer (Q), the content ratio of the polymer (P) is 3% by mass with respect to a total of 100 parts by mass of the polymer (P) and the polymer (Q). The amount is preferably 5 parts by mass or more, more preferably 5 to 95 parts by mass, further preferably 10 to 90 parts by mass, and particularly preferably 15 to 85 parts by mass. As the polymer (P) and the polymer (Q), one type may be used alone, or two or more types may be used in combination.

The liquid crystal alignment agent of the present disclosure may contain a component other than the polymer (Q) as another component. Examples of other components include a polymer (P) and a polymer other than the polymer (Q) (hereinafter, referred to as "other polymer"), and a compound having at least one epoxy group in the molecule (hereinafter, "" "Epoxy group-containing compound"), functional silane compound, photopolymerizable compound, antioxidant, metal chelate compound, curing accelerator, cross-linking agent, imidization accelerator, surfactant, filler, dispersant, light Examples thereof include sensitizers, acid generators, base generators and radical generators. The liquid crystal alignment agent of the present disclosure preferably contains at least one selected from the group consisting of a functional silane compound, an acid generator, a base generator and a radical generator together with the polymer (P).

(Other polymers)
Other polymers can be used to improve solution and electrical properties. Examples of such other polymers include polymers having a main skeleton such as polyorganosiloxane, polyester, polyamide, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, and poly (meth) acrylate. Can be mentioned. The blending ratio of the other polymers is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and 20 parts by mass with respect to 100 parts by mass of the total of the polymers to be mixed in the liquid crystal alignment agent. The following is more preferable.

(Epoxy group-containing compound)
The epoxy group-containing compound can be used to improve the adhesiveness and electrical properties of the liquid crystal alignment film to the substrate surface. Examples of such an epoxy group-containing compound include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylol propantriglycidyl ether, N, N, N', N'-. Tetraglycidyl-m-xylylene diamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N, N , N', N'-tetrax (2-hydroxyethyl) ethylenediamine, N, N-diglycidyl-benzylamine, N, N-diglycidyl-aminomethylcyclohexane, N, N-diglycidyl-cyclohexylamine and the like. In addition, as an example of the epoxy group-containing compound, the epoxy group-containing polyorganosiloxane described in International Publication No. 2009/096598 can be used. When the epoxy group-containing compound is added to the liquid crystal alignment agent, the blending ratio thereof is preferably 50 parts by mass or less with respect to a total of 100 parts by mass of the polymers contained in the liquid crystal alignment agent. It is more preferably 30 parts by mass.

(Functional silane compound)
The functional silane compound can be used for the purpose of improving the printability of the liquid crystal alignment agent. Examples of such functional silane compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, and 3-ureidopropyltriethoxysilane. Silane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, 10-trimethoxysilyl-1,4,7-triazadecane, N-benzyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltri Examples thereof include methoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane and the like. When the functional silane compound is added to the liquid crystal alignment agent, the blending ratio thereof is preferably 5 parts by mass or less, more preferably 0.02 to 3 parts by mass, and 0.1 by mass, based on 100 parts by mass of the total amount of the polymer. ~ 2 parts by mass is more preferable.

(Acid generator)
As the acid generator, a compound known as a compound that generates an acid by heat or light can be appropriately selected and used. Specifically, as a thermoacid generator, for example, an iodonium salt such as diphenyliodonium trifluoromethanesulfonate and bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, and as a photoacid generator, for example, triphenylsulfonium trifluoromethane. Sulfonium salts such as sulfonates; 1- (4-n-butoxynaphthalene-1-yl) tetrahydrothiophenium trifluoromethanesulfonate tetrahydrothiophenium salts; N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept Examples of N-sulfonyloxyimide compounds such as -5-en-2 and 3-dicarboxyimide can be mentioned respectively. When the acid generator is added to the liquid crystal alignment agent, the blending ratio thereof is preferably 50 parts by mass or less, more preferably 0.1 to 30 parts by mass, based on 100 parts by mass of the total polymer.

(Base generator)
As the base generator, a compound known as a compound that generates a base by heat or light can be appropriately selected and used. Specifically, for example, an imidazole-based thermobase generator; orthonitrobenzyl carbamate-based, α, α-dimethyl-3,5-dimethoxybenzyl carbamate-based, acyloxyimino-based photobase generator and the like can be used. When the base generator is added to the liquid crystal alignment agent, the blending ratio thereof is preferably 50 parts by mass or less, more preferably 0.1 to 30 parts by mass, based on 100 parts by mass of the total polymer.

(Radical generator)
As the radical generator, a compound known as a compound that generates radicals by heat or light can be appropriately selected and used. Specifically, examples of the thermal radical generator include peroxides such as t-butyl hydroperoxide and t-butyl peroxyacetate; azobisisobutyronitrile (AIBN) and 2,2'-azobis (isobutyronitrile). ) And other azo compounds; redox-based initiators; etc., as photoradical generators, such as acetophenone, 1-hydroxycyclohexylphenyl ketone, fluorene, triphenylamine, 3-methylacetophenone, 4,4'-dimethoxybenzophenone, 2 -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone and the like can be mentioned respectively. When the radical generator is added to the liquid crystal alignment agent, the blending ratio thereof is preferably 50 parts by mass or less, more preferably 0.1 to 30 parts by mass, based on 100 parts by mass of the total polymer.

<Solvent>
The liquid crystal alignment agent of the present disclosure is prepared as a liquid composition in which the polymer (P) and other components used as needed are preferably dispersed or dissolved in a suitable solvent.
Examples of the organic solvent used include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide. , N, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, Ethyl glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl Examples thereof include ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate and propylene carbonate. These can be used alone or in admixture of two or more.

The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., but is preferable. It is in the range of 1 to 10% by mass. That is, the liquid crystal alignment agent is applied to the surface of the substrate as described later, and is preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that becomes a liquid crystal alignment film. At this time, if the solid content concentration is less than 1% by mass, the film thickness of the coating film becomes too small and it becomes difficult to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by mass, the film thickness of the coating film becomes excessive and it is difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases and the coatability deteriorates. There is a tendency.
The content ratio of the polymer (P) in the liquid crystal alignment agent of the present disclosure is preferably 3 parts by mass or more, more preferably 5 parts by mass, based on 100 parts by mass of the total of the solid components (components other than the solvent) in the liquid crystal alignment agent. It is 10 parts by mass or more, more preferably 10 parts by mass or more.

≪Liquid crystal alignment film and liquid crystal element≫
The liquid crystal alignment film of the present disclosure is formed by the liquid crystal alignment agent prepared as described above. Further, the liquid crystal element of the present disclosure includes a liquid crystal alignment film formed by using the liquid crystal alignment agent described above. The operation mode of the liquid crystal in the liquid crystal element is not particularly limited, and for example, TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, VA (Vertical Alignment) type (including VA-MVA type, VA-PVA type, etc.) , IPS (In-Plane Switching) type, FFS (fringe field switching) type, OCB (Optically Compensated Bend) type and the like. The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, the substrate used differs depending on the desired operation mode. Steps 2 and 3 are common to each operation mode.

(Step 1: Formation of coating film)
First, a liquid crystal alignment agent is applied onto the substrate, and preferably the coated surface is heated to form a coating film on the substrate. As the substrate, for example, glass such as float glass and soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, and poly (aliphatic olefin) can be used. As the transparent conductive film provided on one surface of a substrate, NESA film (US PPG registered trademark) made of tin oxide (SnO _2), indium oxide - such as an ITO film made of tin oxide _{(In 2} O 3 -SnO ₂₎ the Can be used. When manufacturing a TN type, STN type or VA type liquid crystal element, two substrates provided with a patterned transparent conductive film are used. On the other hand, in the case of manufacturing an IPS type or FFS type liquid crystal element, a substrate provided with an electrode made of a transparent conductive film or a metal film patterned in a comb-tooth shape, and a facing substrate not provided with an electrode. Is used. As the metal film, a film made of a metal such as chromium can be used. The liquid crystal alignment agent is applied to the substrate on the electrode forming surface, preferably by an offset printing method, a spin coating method, a roll coater method, or an inkjet printing method.

After the liquid crystal alignment agent is applied, preheating is preferably performed for the purpose of preventing the applied liquid crystal alignment agent from dripping. The pre-baking temperature is preferably 30 to 200 ° C., and the pre-baking time is preferably 0.25 to 10 minutes. Then, a firing (post-baking) step is carried out for the purpose of completely removing the solvent and, if necessary, thermally imidizing the amic acid structure present in the polymer. The firing temperature (post-baking temperature) at this time is preferably 80 to 300 ° C., and the post-baking time is preferably 5 to 200 minutes. The film thickness of the film thus formed is preferably 0.001 to 1 μm. By applying the liquid crystal alignment agent on the substrate and then removing the organic solvent, a liquid crystal alignment film or a coating film to be a liquid crystal alignment film is formed.

(Step 2: Orientation treatment)
When manufacturing a TN type, STN type, IPS type or FFS type liquid crystal element, a treatment (alignment treatment) for imparting a liquid crystal alignment ability to the coating film formed in the above step 1 is performed. As a result, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film. The orientation treatment includes a rubbing treatment that imparts liquid crystal orientation ability to the coating film by rubbing the coating film in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, and cotton, and a coating film formed on the substrate. Examples thereof include a photo-alignment treatment in which the coating film is irradiated with light to impart a liquid crystal alignment ability to the coating film. In particular, since the polymer (P) has high photosensitivity and can exhibit anisotropy in the coating film even with a small exposure amount, the photoalignment method can be preferably applied. On the other hand, in the case of producing a vertically oriented liquid crystal element, the coating film formed in the above step 1 can be used as it is as a liquid crystal alignment film, but the coating film may be subjected to an orientation treatment.

The light irradiation in the photoalignment treatment includes a method of irradiating the coating film after the post-baking step, a method of irradiating the coating film after the pre-baking step and before the post-baking step, and at least the pre-baking step and the post-baking step. In any of these methods, the coating film can be irradiated while the coating film is being heated, or the like. In the photo-alignment treatment, as the radiation to irradiate the coating film, for example, ultraviolet rays including light having a wavelength of 150 to 800 nm and visible light can be used. Preferably, it is ultraviolet light containing light having a wavelength of 200 to 400 nm. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation to be used is linearly polarized light or partially polarized light, the irradiation may be performed from a direction perpendicular to the substrate surface, may be performed from an oblique direction, or may be performed in combination thereof. When irradiating unpolarized radiation, the direction of irradiation is diagonal.
As the light source to be used, for example, 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, or the like can be used. The irradiation amount of radiation is preferably 400 to 50,000 J / m ² , and more preferably 1,000 to 20,000 J / m ² . The light irradiation on the coating film may be performed while heating the coating film in order to enhance the reactivity.

After irradiation with light to impart orientation ability, the surface of the substrate is washed with, for example, water, an organic solvent (for example, methanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.) or a mixture thereof. , The process of heating the substrate may be performed. When a coating film is formed using the liquid crystal alignment agent of the present disclosure, it is preferable that a liquid crystal element having good display performance can be obtained without performing such cleaning treatment or heat treatment, and the process can be reduced.

(Step 3: Construction of liquid crystal cell)
A liquid crystal cell is manufactured by preparing two substrates on which the liquid crystal alignment film is formed as described above and arranging the liquid crystal between the two substrates arranged opposite to each other. In order to manufacture a liquid crystal cell, for example, (1) two substrates are arranged facing each other through a gap (spacer) so that the liquid crystal alignment films face each other, and the peripheral portion of the two substrates is used with a sealant. A method of injecting and filling the liquid crystal into the surface of the substrate and the cell gap partitioned by the sealant, and then sealing the injection holes. (2) Sealing at a predetermined place on one of the substrates on which the liquid crystal alignment film is formed. A method in which an agent is applied, liquid crystal is further dropped onto a predetermined number of places on the liquid crystal alignment film surface, the other substrate is bonded so that the liquid crystal alignment film faces each other, and the liquid crystal is spread over the entire surface of the substrate (ODF method). ) Etc. can be mentioned. It is desirable to remove the flow orientation at the time of filling the liquid crystal by further heating the manufactured liquid crystal cell to a temperature at which the used liquid crystal takes an isotropic phase and then slowly cooling it to room temperature.

As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used. As the spacer, a photo spacer, a bead spacer, or the like can be used. Examples of the liquid crystal include nematic liquid crystal and smectic liquid crystal, and among them, nematic liquid crystal is preferable, and for example, shift-based liquid crystal, azoxy-based liquid crystal, biphenyl-based liquid crystal, phenylcyclohexane-based liquid crystal, ester-based liquid crystal, terphenyl-based liquid crystal, and biphenyl. Cyclohexane-based liquid crystals, pyrimidine-based liquid crystals, dioxane-based liquid crystals, bicyclooctane-based liquid crystals, Cuban-based liquid crystals, and the like can be used. Further, for example, a cholesteric liquid crystal, a chiral agent, a ferroelectric liquid crystal or the like may be added to these liquid crystals for use.

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 polyvinyl alcohol is stretch-oriented and iodine is absorbed is sandwiched between a cellulose acetate protective film, or a polarizing plate made of the H film itself.

The liquid crystal elements of the present disclosure can be effectively applied to various applications, for example, clocks, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors. , LCD TVs, information displays and other display devices, dimming films and the like. Further, the liquid crystal element formed by using the liquid crystal alignment agent of the present disclosure can also be applied to a retardation film.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

In the following example, the molecular weight of the polymer was measured by the following method.
[Molecular weight of polymer]
The polystyrene-equivalent number average molecular weight (Mn) and weight average molecular weight (Mw) were measured by gel permeation chromatography (GPC) under the following conditions, and the molecular weight distribution (Mw / Mn) was determined.
Measuring device: HLC-8020 manufactured by Tosoh Corporation
Column: Tosoh Corporation, TSK guardgroup α, TSK gel α-M, and TSK gel α-2500 are connected in series and used. Developing solvent: Lithium bromide / monohydrate for 3 L of dimethylformamide 9. Solution in which 4 g and 1.7 g of phosphoric acid are dissolved Temperature: 35 ° C
Flow velocity: 1.0 mL / min

The structures and abbreviations of the main compounds used in the examples below are as follows.
(Tetracarboxylic dianhydride)
TA-1; 1,2,3,4-butanetetracarboxylic dianhydride TA-2; 1,2,3,4-cyclobutanetetracarboxylic dianhydride TA-3; (1R, 2R, 3S, 4S) ) -1,3-Dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride TA-4; trans-1,2,3,4-cyclopentanetetracarboxylic dianhydride TA-5; 2 , 3,5-Tricarboxycyclopentylacetic acid dianhydride TA-6; pyromellitic dianhydride

(Diamine)
DA-1; Paraphenylenediamine DA-2; 4,4'-diaminodiphenylmethane DA-3; 4,4'-ethylenedianiline DA-4; 2,2'-dimethyl-4,4'-diaminobiphenyl DA- 5; N- (tert-butoxycarbonyl) -2,5-diaminobenzylamine DA-6; 4-amino-N- (4-aminophenyl) -N- (tert-butoxycarbonyl) benzamide DA-7; 4, 4'-Diaminodiphenylamine DA-8; 4,4'-diamino-N4, N4'-bis (4-aminophenyl) -N4, N4'-dimethylbiphenyl DA-9: N-2- (4-aminophenylethyl) ) -N-Methylamine DA-10: 6,6'-(piperazin-1,4-diyl) -bis (pyridine-3-amine)
DA-11: 1,4-phenoxylen-bis (4-aminobenzonate)
DA-12: 4-aminophenyl-3- (4-aminophenyl) -2-methylacrylate

(Terminal modifier)
EC-1; Methacryloyl chloride EC-2; 2-Francarbonyl chloride EC-3; Furfurylamine EC-4; 2-Aminoethanethiol EC-5; N- (tert-butoxycarbonyl) -1,2-diaminoethane

(Imidation accelerator)
I-1; 3- (2-hydroxyphenyl) -N- (pyridine-3-ylmethyl) propanamide I-2; N-α- (9-fluorenylmethoxycarbonyl) -N- (tert-butoxycarbonyl) -L-histidine (functional silane compound)
S-1; 3-glycidoxypropylmethyldiethoxysilane (epoxy group-containing compound)
CL-1; N, N, N', N'-tetraglycidyl-4,4'-diaminodiphenylmethane CL-2; N, N, N', N'-tetrakis (2-hydroxyethyl) ethylenediamine (dehydration catalyst)
DMT-MM; 4- (4,6-dimethoxy-1,3,5-triazine-2-yl) -4-methylmorpholinium chloride (solvent)
NMP; N-methyl-2-pyrrolidone γBL; γ-butyrolactone BC; butyl cellosolve

[Example 1a]
In a 200 mL three-necked flask equipped with a nitrogen introduction tube, a reflux condenser, and a thermometer, 22.42 g (100 mmol) of TA-3, 100 mL of tetrahydrofuran, and 0.79 g (10.0 mmol) of pyridine were placed under a nitrogen stream. It was stirred and suspended. 15.14 g (210 mmol) of β-metharyl alcohol was added to this suspension, and the mixture was stirred at room temperature for 2 hours. The reaction was further carried out at 60 ° C. for 8 hours to obtain a colorless and transparent solution. This reaction solution is concentrated under reduced pressure at 60 ° C., further vacuum dried, and a mixture of a compound represented by the following formula (DE-1a) and a compound represented by the following formula (DE-1b) (hereinafter, DE-1a). 36.84 g (called / b) was obtained.

[Example 2a]
18.42 g (50.0 mmol) of DE-1a / b and 100 mL of toluene were placed in a 100 mL eggplant flask equipped with a nitrogen introduction tube and a reflux condenser, and the mixture was stirred at 80 ° C. for 30 minutes. Then, the mixture was cooled to room temperature with 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 DE-1a as a white powder (42.0 mmol, yield 84%).

[Example 3a]
In a 500 mL three-necked flask equipped with a nitrogen introduction tube, a reflux condenser, and a thermometer, 14.74 g (40.0 mmol) of DE-1a, 80 mL of heptane, and 0.032 g (0.40 mmol) of pyridine were placed in a nitrogen stream. The mixture was stirred at 75 ° C. below. 14.28 g (120 mmol) of thionyl chloride was slowly added dropwise over 20 minutes, and foaming as the reaction proceeded was confirmed. After completion of the dropping, the 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 a colorless transparent liquid represented by the following formula (DC-1a) (39.2 mmol, Yield 98%).

[Example 4a]
The compound represented by the following formula (DE-2a) and the following formula (DE-2a) are obtained in the same manner as in Example 1a except that 15.14 g (210 mmol) of β-metharyl alcohol is changed to 20.60 g (210 mmol) of furfuryl alcohol. 42.04 g of a mixture (hereinafter referred to as DE-2a / b) with the compound represented by DE-2b) was obtained.

[Example 5a]
In a 100 mL three-necked flask equipped with a nitrogen introduction tube, a reflux condenser, and a thermometer, 9.81 g (50 mmol) of TA-2, 50 mL of tetrahydrofuran, and 0.40 g (5.0 mmol) of pyridine were placed under a nitrogen stream. It was stirred and suspended. 13.66 g (105 mmol) of 2-hydroxyethyl methacrylate was added to this suspension, and the mixture was stirred at room temperature for 2 hours. The reaction was further carried out at 40 ° C. for 24 hours to obtain a colorless and transparent solution. This reaction solution is concentrated under reduced pressure at 40 ° C., further vacuum dried, and a mixture of a compound represented by the following formula (DE-3a) and a compound represented by the following formula (DE-3b) (hereinafter, DE-3a). 22.82 g (called / b) was obtained.

[Example 6a]
The compound represented by the following formula (DE-4a) and the following formula (DE) are the same as in Example 1a except that 15.14 g (210 mmol) of β-metharyl alcohol is changed to 11.77 g (210 mmol) of propargyl alcohol. 33.63 g of a mixture with the compound represented by -4b) (hereinafter referred to as DE-4a / b) was obtained.

[Example 7a]
The compound represented by the following formula (DE-5a) and the following formula (DE) are the same as in Example 1a except that 15.14 g (210 mmol) of β-metallic alcohol is changed to 15.56 g (210 mmol) of hydroxyacetone. 37.23 g of a mixture with the compound represented by −5b) (hereinafter referred to as DE-5a / b) was obtained.

[Example 8a]
A compound represented by the following formula (DE-6a) in the same manner as in Example 5a except that 13.66 g (105 mmol) of 2-hydroxyethyl methacrylate was changed to 12.40 g (105 mmol) of glycerol 1,2-carbonate. 21.61 g of a mixture (hereinafter referred to as DE-6a / b) with the compound represented by the following formula (DE-6b) was obtained.

[Synthesis Example 9]
In a 100 mL three-necked flask equipped with a nitrogen introduction tube, a reflux condenser tube, and a thermometer, 9.81 g (50 mmol) of 1S, 2S, 4R, 5R-cyclohexanetetracarboxylic dianhydride, 50 mL of tetrahydrofuran, and 0. 40 g (5.0 mmol) was added, and the mixture was suspended by stirring under a nitrogen stream. 6.4 g (200 mmol) of methanol was added to this suspension, and the mixture was stirred at room temperature for 24 hours to obtain a colorless and transparent solution. This reaction solution is concentrated under reduced pressure at 60 ° C., further vacuum dried, and a mixture of a compound represented by the following formula (DE-7a) and a compound represented by the following formula (DE-7b) (hereinafter, DE-7a). 14.41 g (called / b) was obtained.

[Synthesis Example 10]
A compound represented by the following formula (DE-8a) was synthesized according to the method described in Example 4 of International Publication No. 2010/092989. In addition, a compound represented by the following formula (DC-8a) was synthesized according to the method described in Example 47 of International Publication No. 2010/092989.

[Synthesis Example 11]
1.63 g (11.0 mmol) of 3,4-dihydrocoumarin and 1.08 g (10.) of 3- (aminomethyl) pyridine in a 50 mL eggplant flask equipped with a nitrogen introduction tube, a reflux condenser tube, and a thermometer. (0 mmol), 10 mL of tetrahydrofuran was added, and the mixture was heated under reflux at 80 ° C. for 3 hours under a nitrogen stream. 40 ml of heptane was added to this reaction solution to precipitate the product, which was filtered. The obtained solid was washed with heptane and dried under reduced pressure to obtain 2.51 g (9.8 mmol) of 3- (2-hydroxyphenyl) -N- (pyridin-3-ylmethyl) propanamide.

[Synthesis Example 12]
N- (tert-butoxycarbonyl) -2,5-diaminobenzylamine was synthesized according to the method described in Synthesis Example 7 of WO2011 / 115118.

[Example 1]
In a 50 mL three-necked flask equipped with a nitrogen introduction tube and a thermometer, 3.54 g (9.6 mmol) of DE-1a / b, 1.08 g (10.0 mmol) of DA-1, 31.0 g of NMP, and triethylamine. 0.51 g (5.0 mmol) was added, the mixture was cooled to about 10 ° C., 8.30 g (30.0 mmol) of DMT-MM, which is a triazine-based dehydration condensing agent, was added, and the mixture was reacted at room temperature under a nitrogen stream for 24 hours. The obtained polymerization solution was diluted with NMP and slowly poured into methanol with stirring to coagulate. The precipitated solid was recovered, stirred and washed twice in methanol, and vacuum dried at 60 ° C. to obtain a white powder of polyamic acid ester (PAE-1). The number average molecular weight Mn of this polymer was 11,000, and the molecular weight distribution Mw / Mn was 3.0.

[Example 2]
A polyamic acid ester (PAE-2) was obtained in the same manner as in Example 1 except that DE-1a / b was changed to 3.54 g (9.6 mmol) of DE-1a. The number average molecular weight Mn of this polymer was 12,000, and the molecular weight distribution Mw / Mn was 4.1.

[Example 3]
The polyamic acid ester (PAE-) was the same as in Example 1 except that DE-1a / b was changed to DE-1a 2.83 (7.68 mmol) and DE-7a / b 0.553 g (1.92 mmol). 3) was obtained. The number average molecular weight Mn of this polymer was 21,000, and the molecular weight distribution Mw / Mn was 3.5.

[Example 4]
1.03 g (9.5 mmol) of DA-1, 0.106 g (0.50 mmol) of DA-3, and 20.0 g of NMP were placed in a 50 mL three-necked flask equipped with a nitrogen introduction tube and a thermometer at about 10 ° C. To prepare a diamine solution. An acid chloride solution prepared by previously dissolving 3.89 g (9.6 mmol) of DC-1a in 1.90 g (21.6 mmol) of pyridine and 20.0 g of γBL was added thereto, and the mixture was reacted at room temperature for 4 hours under a nitrogen stream. It was. 0.209 g (2.0 mmol) of EC-1 was added to this polymerization solution, and the mixture was further reacted for 4 hours. The obtained polymerization solution was diluted with γBL and slowly poured into deionized water with stirring to coagulate. The precipitated solid was recovered, stirred and washed twice in isopropanol, and vacuum dried at 60 ° C. to obtain a white powder polyamic acid ester (PAE-4). The number average molecular weight Mn of this polymer was 8,000, and the molecular weight distribution Mw / Mn was 2.1.

[Example 5]
0.973 g (9.0 mmol) of DA-1, 0.327 g (1.0 mmol) of DA-6, and 20.0 g of NMP were placed in a 50 mL three-necked flask equipped with a nitrogen introduction tube and a thermometer at about 10 ° C. To prepare a diamine solution. An acid chloride solution prepared by previously dissolving 3.89 g (9.6 mmol) of DC-1a in 1.90 g (21.6 mmol) of pyridine and 20.0 g of γBL was added thereto, and the mixture was reacted at room temperature for 4 hours under a nitrogen stream. It was. 0.261 g (2.0 mmol) of EC-2 was added to this polymerization solution, and the mixture was further reacted for 4 hours. The obtained polymerization solution was diluted with γBL and slowly poured into deionized water with stirring to coagulate. The precipitated solid was recovered, stirred and washed twice in isopropanol, and vacuum dried at 60 ° C. to obtain a white powder polyamic acid ester (PAE-5). The number average molecular weight Mn of this polymer was 25,000, and the molecular weight distribution Mw / Mn was 4.5.

[Example 6]
In a 50 mL three-necked flask equipped with a nitrogen introduction tube and a thermometer, 4.04 g (9.6 mmol) of DE-2a / b, 0.995 g (9.2 mmol) of DA-1 and 0.078 g (EC-3) of EC-3 ( 0.8 mmol), 31.0 g of NMP, 0.51 g (5.0 mmol) of triethylamine, cooled to about 10 ° C., 8.30 g (30.0 mmol) of DMT-MM was added, and 24 at room temperature under a nitrogen stream. Reacted for time. The obtained polymerization solution was diluted with NMP and slowly poured into methanol with stirring to coagulate. The precipitated solid was recovered, stirred and washed twice in methanol, and vacuum dried at 60 ° C. to obtain a white powder polyamic acid ester (PAE-6). The number average molecular weight Mn of this polymer was 15,000, and the molecular weight distribution Mw / Mn was 3.2.

[Example 7]
In a 50 mL three-necked flask equipped with a nitrogen introduction tube and a thermometer, 2.19 g (4.8 mmol) of DE-3a / b, 1.38 g (4.8 mmol) of DE-8a, and 1.08 g (DA-1). 10.0 mmol), 31.0 g of NMP, 0.51 g (5.0 mmol) of triethylamine, cooled to about 10 ° C., 8.30 g (30.0 mmol) of DMT-MM was added, and 24 at room temperature under a nitrogen stream. Reacted for time. The obtained polymerization solution was diluted with NMP and slowly poured into methanol with stirring to coagulate. The precipitated solid was recovered, stirred and washed twice in methanol, and vacuum dried at 60 ° C. to obtain a white powder polyamic acid ester (PAE-7). The number average molecular weight Mn of this polymer was 18,000, and the molecular weight distribution Mw / Mn was 1.8.

[Example 8]
In a 50 mL three-necked flask equipped with a nitrogen inlet tube and a thermometer, 3.23 g (9.6 mmol) of DE-4a / b, 0.995 g (9.2 mmol) of DA-1, and 0.062 g of EC-4 (0.062 g). 0.8 mmol), 31.0 g of NMP, 0.51 g (5.0 mmol) of triethylamine, cooled to about 10 ° C., 8.30 g (30.0 mmol) of DMT-MM was added, and 24 at room temperature under a nitrogen stream. Reacted for time. The obtained polymerization solution was diluted with NMP and slowly poured into methanol with stirring to coagulate. The precipitated solid was recovered, stirred and washed twice in methanol, and vacuum dried at 60 ° C. to obtain a white powder polyamic acid ester (PAE-8). The number average molecular weight Mn of this polymer was 12,000, and the molecular weight distribution Mw / Mn was 3.3.

[Example 9]
In a 50 mL three-necked flask equipped with a nitrogen inlet tube and a thermometer, 3.57 g (9.6 mmol) of DE-5a / b, 0.796 g (7.36 mmol) of DA-1, and 0.437 g of DA-5 (0.437 g). 1.84 mmol), 0.128 g (0.80 mmol) of EC-5, 31.0 g of NMP, 0.51 g (5.0 mmol) of triethylamine, cooled to about 10 ° C., and 8.30 g of DMT-MM. (30.0 mmol) was added, and the mixture was reacted at room temperature under a nitrogen stream for 24 hours. The obtained polymerization solution was diluted with NMP and slowly poured into methanol with stirring to coagulate. The precipitated solid was recovered, stirred and washed twice in methanol, and vacuum dried at 60 ° C. to obtain a white powder polyamic acid ester (PAE-9). The number average molecular weight Mn of this polymer was 12,000, and the molecular weight distribution Mw / Mn was 3.5.

[Example 10]
In a 50 mL three-necked flask equipped with a nitrogen inlet tube and a thermometer, 2.08 g (4.8 mmol) of DE-6a / b, 1.38 g (4.8 mmol) of DE-8a, and 0.796 g of DA-1 (DA-1). 7.36 mmol), 0.437 g (1.84 mmol) of DA-5, 0.128 g (0.80 mmol) of EC-5, 31.0 g of NMP, 0.51 g (5.0 mmol) of triethylamine, and so on. The mixture was cooled to 10 ° C., 8.30 g (30.0 mmol) of DMT-MM was added, and the mixture was reacted at room temperature under a nitrogen stream for 24 hours. The obtained polymerization solution was diluted with NMP and slowly poured into methanol with stirring to coagulate. The precipitated solid was recovered, stirred and washed twice in methanol, and vacuum dried at 60 ° C. to obtain a white powder polyamic acid ester (PAE-9). The number average molecular weight Mn of this polymer was 20,000, and the molecular weight distribution Mw / Mn was 3.0.

[Synthesis Example 13]
1.08 g (10.0 mmol) of DA-1 and 16.0 g of NMP were placed in a 50 mL three-necked flask equipped with a nitrogen introduction tube and a thermometer, and cooled to about 10 ° C. to prepare a diamine solution. An acid chloride solution prepared by previously dissolving 3.12 g (9.6 mmol) of DC-8a in 1.90 g (21.6 mmol) of pyridine and 16.0 g of γBL was added thereto, and the mixture was reacted at room temperature for 4 hours under a nitrogen stream. It was. The obtained polymerization solution was diluted with γBL and slowly poured into deionized water with stirring to coagulate. The precipitated solid was recovered, stirred and washed twice in isopropanol, and vacuum dried at 60 ° C. to obtain a white powder polyamic acid ester (PAE-11). The number average molecular weight Mn of this polymer was 19,000, and the molecular weight distribution Mw / Mn was 1.5.

[Synthesis Example 14]
100 parts by mass of TA-3 as a tetracarboxylic dianhydride and 100 parts by mass of DA-1 as a diamine were dissolved in NMP and reacted at room temperature for 6 hours to contain 20% by mass of polyamic acid (PAA-1). Obtained a solution to be prepared.

[Synthesis Example 15]
100 parts by mass of TA-2 as a tetracarboxylic dianhydride and 100 parts by mass of DA-4 as a diamine were dissolved in NMP and reacted at room temperature for 6 hours to contain 20% by mass of polyamic acid (PAA-2). Obtained a solution to be prepared.

[Synthesis Example 16]
100 parts by mass of TA-1 as a tetracarboxylic dianhydride and 100 parts by mass of DA-7 as a diamine were dissolved in NMP and reacted at room temperature for 6 hours to contain 20% by mass of polyamic acid (PAA-3). Obtained a solution to be prepared.

[Synthesis Example 17]
Dissolve 100 parts by mass of TA-4 as tetracarboxylic dianhydride, 80 parts by mass of DA-2 as diamine and 20 parts by mass of DA-8 in NMP, and react at room temperature for 6 hours to carry out polyamic acid (PAA). A solution containing 20% by mass of -3) was obtained.

The types and blending ratios of the compounds used in the synthesis of the polymer are shown in Table 1 below. In Table 1 below, "molar ratio" represents the usage ratio (molar ratio) of each compound used in the synthesis (the same applies to Table 3 below).

[Example 11: Photo-alignment FFS type liquid crystal display element]
(1) Preparation of liquid crystal alignment agent The polymer (PAE-1) obtained in Example 1 as a polymer is mixed with γ-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC). It was dissolved in a solvent (GBL: NMP: BC = 80: 10: 10 (mass ratio)) to prepare a solution having a solid content concentration of 4.0% by mass. A liquid crystal alignment agent (R-1) was prepared by filtering this solution through a filter having a pore size of 0.2 μm.

(2) Evaluation of coatability The liquid crystal alignment agent (R-1) prepared above is coated on a glass substrate using a spinner, prebaked on a hot plate at 80 ° C. for 1 minute, and then nitrogen is stored in the oven. By heating (post-baking) for 30 minutes in the replaced oven at 230 ° C., a coating film having an average film thickness of 0.1 μm was formed. This coating film was observed with a microscope at 100 times and 10 times magnification to check for uneven film thickness and the presence or absence of pinholes. The evaluation was "good" when both film thickness unevenness and pinholes were not observed even when observed with a 100x microscope, and at least one of film thickness unevenness and pinholes was observed with a 100x microscope. However, when both film thickness unevenness and pinholes were not observed with a 10x microscope, the coatability was "OK", and when at least one of the film thickness unevenness and pinholes was clearly observed with a 10x microscope. Was defined as "poor" coatability. In this example, neither uneven film thickness nor pinholes was observed even with a 100x microscope, and the coatability was "good".

^{(3) Measurement of imidization rate of polymer component in coating film Absorption around 1360 cm -1} in FT-IR measurement for the coating film obtained in (2) above (absorption derived from CN expansion and contraction vibration of imide group) The imidization rate (%) was calculated by the following formula (4) from the absorbance α1 according to () and the absorbance α2 due to absorption near 1500 cm ^{-1 (absorption derived from C = C stretching vibration of the aromatic ring).}
Imidization rate (%) = {(α1 _{230 ° C} / α2 _{230 ° C} ) / (α1 _{300 ° C} / α2 _{300 ° C} )} × 100… (4)
(In the formula (4), α1 _{230 ° C.} and α2 _{230 ° C.} are the measurement results of the coating film obtained in (2) above, and α1 _{300 ° C.} and α2 _{300 °} C. are ovens at 300 ° C. in which the inside of the oven is replaced with nitrogen. This is the measurement result of the coating film heated at 300 ° C., where the imidization rate of the coating film heated at 300 ° C. is 100%.)
As a result, the imidization rate of this coating film was 30%.

(4) Adhesion Using the coating film produced in (2) above, the adhesion between the coating film formed by the liquid crystal alignment agent and the substrate was evaluated. First, using an evenly spaced spacer with a guide, cuts were made in the coating film with a cutter knife to form 10 × 10 lattice patterns within a range of 1 cm × 1 cm. The depth of each cut was set to reach the middle of the coating film. Next, the cellophane tape was brought into close contact with the cellophane tape so as to cover the entire surface of the lattice pattern, and then the cellophane tape was peeled off. The cut portion of the lattice pattern after peeling was visually observed under the cloth Nicol to evaluate the adhesion. The evaluation is that the adhesion is "◎" when no peeling is confirmed at the part along the cut line and at the intersection of the grid patterns, and the number of grids where peeling is observed in the above part is the number of the entire grid pattern. On the other hand, when it was less than 15%, the adhesion was “◯”, when it was 15% or more and less than 20%, it was evaluated as “Δ”, and when it was 20% or more, it was evaluated as “x”. As a result, this coating film had an adhesiveness of "Δ".

(5) Manufacture of liquid crystal display element by photoalignment method On each surface of a glass substrate in which a flat plate electrode, an insulating layer and a comb-shaped electrode are laminated on one side in this order, and a facing glass substrate on which no electrode is provided. The liquid crystal aligning agent (R-1) prepared above was applied using a spinner so that the film thickness was 0.1 μm, and dried on a hot plate at 80 ° C. for 1 minute and in a clean oven at 200 ° C. for 1 hour. To form a coating film. A liquid crystal alignment film was formed on the surface of the coating film by irradiating the surface of the coating film with polarized ultraviolet rays of 500 mJ / cm ^{2 containing a bright line of 254 nm from the normal direction of the substrate using an Hg-Xe lamp.} Next, the pair of substrates subjected to the light irradiation treatment were screen-printed with an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm, leaving a liquid crystal injection port on the edge of the surface on which the liquid crystal alignment film was formed. The substrates were overlapped and pressure-bonded so that the projection directions of the polarizing axes on the substrate surface at the time of light irradiation were antiparallel, and the adhesive was thermoset at 150 ° C. for 1 hour. Next, a nematic liquid crystal (MLC-7028 manufactured by Merck & Co., Inc.) was filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Further, in order to eliminate the flow orientation at the time of liquid crystal injection, this was heated at 150 ° C. and then slowly cooled to room temperature. Next, a polarizing plate was attached to both outer surfaces of the substrate to produce a transverse electric field (FFS) type liquid crystal display element.

(6) Evaluation of liquid crystal orientation With respect to the liquid crystal display element manufactured in (5) above, the presence or absence of abnormal domains in the change in brightness when a voltage of 5 V is turned ON / OFF (applied / released) is measured with a microscope at a magnification of 50 times. Observed. In the evaluation, the case where no abnormal domain was observed was regarded as "good" in liquid crystal orientation, and the case where abnormal domain was observed was regarded as "poor" in liquid crystal orientation. As a result, it was evaluated as "good" in this example.

(7) Contrast evaluation after drive stress (evaluation of AC afterimage characteristics)
An FFS type liquid crystal cell was produced by performing the same operation as in (5) above except that the polarizing plates were not bonded to both outer surfaces of the substrate. This FFS type liquid crystal cell is driven at an AC voltage of 10 V for 30 hours, and then using a device in which a polarizer and an analyzer are arranged between a light source and a photodetector, the minimum relative represented by the following mathematical formula (2) is used. The transmittance (%) was measured.
Minimum relative transmittance (%) = (β-B0) / (B100-B0) × 100 ... (2)
(In the formula (2), B0 is the amount of light transmitted under the cross Nicol in the blank. B100 is the amount of light transmitted under the paranicol in the blank. β is the polarizer and the analyzer under the cross Nicol. This is the minimum amount of light transmitted by sandwiching a liquid crystal display element between the two.)
The black level in the dark state is represented by the minimum relative transmittance of the liquid crystal display element, and in the FFS type liquid crystal display element, the smaller the black level in the dark state, the better the contrast. If the minimum relative transmittance is less than 1.0%, the AC afterimage characteristic is "◎", if it is 1.0% or more and less than 1.5%, it is "○", and it is 1.5% or more and less than 2.0%. Those with "Δ" and those with 2.0% or more were designated as "x". As a result, the evaluation was "Δ" in this example.

(8) Observation of minute bright spots (heat resistance test)
The evaluation of the minute bright spots was carried out by storing the liquid crystal cell produced by performing the same operation as in (5) above for 21 days in a constant temperature bath at 100 ° C. except that the polarizing plates were not attached to both outer surfaces of the substrate, and then the liquid crystal. This was done by observing the presence or absence of minute bright spots in the cell with a microscope. When the decomposition products generated by light irradiation for photoalignment treatment remain in the film, the decomposition products bleed out to the film surface by exposing the liquid crystal display element to a high temperature environment for a long time, and gradually bleed out in the liquid crystal. It is known that it crystallizes in and is observed as a minute bright spot. The observation area was 680 μm × 680 μm, and the microscope magnification was 100 times. The evaluation is "◎ " when no micro-bright spots are observed, "○ " when the number of micro-bright spots is 1 or 2 points, and the number of micro-bright spots is 3 or more and 5 or less. When 6 or more micro-bright spots were observed, it was rated as "XX". As a result, the evaluation was "○" in this example.

[Examples 12 to 22, Comparative Examples 1 to 3]
In Example 11, the liquid crystal alignment agent was prepared in the same manner as in Example 11 except that the types and blending ratios of the polymers and additives contained in the liquid crystal alignment agent were changed as shown in Table 2 below, and FFS. A type liquid crystal display element or a liquid crystal cell was manufactured and various evaluations were performed. The evaluation results are shown in Table 2 below. In Table 2, the blending ratio of the polymer 1 and the polymer 2 in the liquid crystal aligning agent is indicated by the mass part in terms of solid content, and the blending ratio of the additive 1 and the additive 2 is the polymer 1 and the polymer 2. It is shown by the mass part when the total solid content mass of is 100 parts by mass.

In Examples 11 to 22, the coatability and adhesion of the liquid crystal alignment agent, the liquid crystal orientation in the liquid crystal display element, the AC afterimage characteristic, and the heat resistance were well balanced. In particular, in Examples 14 to 18, 20 and 21, all of the above characteristics were the results of "good", "⊚" or "◯", and the balance of various characteristics was excellent. Further, in Examples 19 and 22, although the AC afterimage characteristic was slightly inferior to the evaluation of "○", the coating property, the liquid crystal orientation, and the heat resistance were good results as in the other examples. It was. On the other hand, Comparative Examples 1 to 3 were inferior to Examples in a plurality of evaluation items.
Further, when Examples 12 to 22 and Comparative Example 1 were compared, the example showed a higher imidization rate and had better AC afterimage characteristics. This is probably because the higher imidization rate enhances the interaction with the liquid crystal and improves the liquid crystal orientation.
Further, from the results of Comparative Example 1, it was found that the polyamic acid had low photodegradability, and the liquid crystal orientation was poor at the same exposure amount of polarized ultraviolet rays.
Further, by comparing Examples 14 to 18 and 20 to 22 with Comparative Example 3, the liquid crystal aligning agent containing the polyamic acid ester having a modified end and the polyamic acid is used for phase separation of the polyamic acid ester and the polyamic acid. It is considered that the derived micro-concavities and convexities were suppressed and the coatability was improved.
From the results of Examples 11 to 22 and Comparative Examples 1 to 3 above, according to the liquid crystal alignment agent containing a polyamic acid ester having a reactive group in the side chain, the decomposition products in the film are washed away after the photoalignment treatment. It was found that the heat resistance (particularly, long-term heat resistance) was good even without the cleaning treatment. It was suggested that in Examples 14 to 18, the long-term heat resistance was particularly excellent, and the diffusion and / or crystallization of the photodegraded product, which is a causative substance of micro-bright spots, was suppressed.

[Synthesis Examples 18 to 22]
A solution containing a polyamic acid (PAA-5 to PAA-9) was obtained in the same manner as in Synthesis Example 14 except that the types and amounts of the tetracarboxylic dianhydride and the diamine compound were changed as shown in Table 3. ..

[Example 23]
1.08 g (10.0 mmol) of DA-1 and 20.0 g of NMP were placed in a 50 mL three-necked flask equipped with a nitrogen introduction tube and a thermometer, and cooled to about 10 ° C. to prepare a diamine solution. An acid chloride solution prepared by previously dissolving 3.89 g (9.6 mmol) of DC-1a in 1.90 g (21.6 mmol) of pyridine and 20.0 g of γBL was added thereto, and the mixture was reacted at room temperature for 4 hours under a nitrogen stream. It was. The obtained polymerization solution was diluted with γBL and slowly poured into deionized water with stirring to coagulate. The precipitated solid was recovered, stirred and washed twice in isopropanol, and vacuum dried at 60 ° C. to obtain a white powder polyamic acid ester (PAE-12). The number average molecular weight Mn of this polymer was 20,000, and the molecular weight distribution Mw / Mn was 3.20.
[Examples 24-27]
Polyamic acid esters (PAE-13 to PAE-16) were obtained in the same manner as in Example 23 except that the types and amounts of the tetracarboxylic acid derivative and the diamine compound were changed as shown in Table 3 below. The number average molecular weight Mn of the polymer (PAE-13) is 22,000 and the molecular weight distribution Mw / Mn is 3.90, and the number average molecular weight Mn of the polymer (PAE-14) is 30,000 and the molecular weight distribution Mw / Mn. The Mn was 4.10. The number average molecular weight Mn of the polymer (PAE-15) is 11,000 and the molecular weight distribution Mw / Mn is 3.00, and the number average molecular weight Mn of the polymer (PAE-16) is 10,000 and the molecular weight distribution Mw / Mn. The Mn was 2.90.

[Example 28]
A polyamic acid ester-polyamic acid copolymer (PAE-17) was synthesized by the following method with reference to the method described in Synthesis Example 4 of International Publication No. 2015/152174.
3.50 g (9.5 mmol) of DE-1a and 55.4 g of NMP were added to a 100 mL three-necked flask equipped with a nitrogen introduction tube and a thermometer, and the mixture was stirred and dissolved. Then, 2.11 g (20.9 mmol) of triethylamine and 2.05 g (19.0 mmol) of DA-1 were added, and the mixture was stirred and dissolved. The solution was cooled to about 10 ° C., 7.28 g (19.0 mmol) of diphenyl phosphonate (2,3-dihydro-2-thioxo-3-benzoxazolyl) was added, and 11.9 g of NMP was further added. Then, the reaction was carried out at room temperature under a nitrogen stream for 12 hours. Then, 0.95 g (3.80 mmol) of diphenyl phosphate and 2.00 g (8.93 mmol) of TA-3 were added, and 11.9 g of NMP was further added, and the mixture was reacted at room temperature under a nitrogen stream for 12 hours. The obtained polymerization solution was slowly poured into methanol (600 g) with stirring to solidify. The precipitated solid was recovered, stirred and washed twice in methanol, and then vacuum dried at 60 ° C. to obtain a powder of polyamic acid ester-polyamic acid copolymer (PAE-17). The number average molecular weight Mn of this polymer was 20,000, and the molecular weight distribution Mw / Mn was 3.50.

[Examples 29 to 41]
In Example 11, the liquid crystal alignment agent was prepared in the same manner as in Example 11 except that the types of the polymer and the additive contained in the liquid crystal alignment agent were changed as shown in Table 4 below, and the FFS type liquid crystal display was performed. A device or a liquid crystal cell was manufactured and various evaluations were performed. The evaluation results are shown in Table 4 below.

Regarding the coatability and adhesion of the liquid crystal alignment agent, the liquid crystal orientation in the liquid crystal display element, the AC afterimage characteristic, and the heat resistance, all of the results were "good", "◎", or "○" in Examples 29 to 41. , Various characteristics were well-balanced. Among them, Example 31 had particularly good liquid crystal orientation and AC afterimage characteristics, and Example 41 had particularly good adhesion.
Further, Examples 29 to 37 were particularly excellent in heat resistance, and exhibited good liquid crystal orientation and AC afterimage characteristics even with a composition in which the ratio of the polymer 1 was as small as 10 parts. It is considered that this is because the polyamic acid ester of the polymer 1 is highly hydrophobic, the layer separation of the polymer 2 from the polyamic acid is promoted, and the polyimide derived from the polymer 1 is likely to be unevenly distributed on the surface layer of the alignment film. Be done. Further, when the ratio of the polymer 1 is small, the amount of photodecomposed products generated is small, so that contamination of the firing furnace can be reduced, and the amount of photodegraded products remaining in the alignment film is small, so that the mixture is exposed to a high temperature environment. Even in this case, the occurrence of minute bright spots is small, and it is considered that the heat resistance is improved.

Claims (8)

A liquid crystal alignment agent containing a polymer (P) having a partial structure represented by the following formula (1).

(In the formula (1), R ¹ is a tetravalent organic group having a cyclobutane ring structure derived from 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride ^{, and R 2} Is a divalent organic group. X ¹ and X ² are independently hydroxyl groups or monovalent organic groups having 1 to 40 carbon atoms, respectively. However, at least one of ^{X 1} and X ^{2 is reactive.} It is a monovalent organic group having a group.) In the above formula (1), ^{at least one of X 1} and X ² consists of a group consisting of a structure represented by each of the following formulas (2-1) to (2-10) and a (meth) acryloyloxy group. The liquid crystal alignment agent according to claim 1, which is one of the selected types.

(In formulas (2-1) to (2-10), R ⁴ is a divalent aliphatic group having 1 to 6 carbon atoms which may have a substituent, and R ⁵ is independent of each other. a hydrogen atom or a monovalent aliphatic group having 1 to 6 carbon atoms which may have a substituent. However, any two aliphatic groups bonded to each other among the R ⁴ and R ⁵ Te may form a ring structure. equation (2-1), a plurality of R ⁵ in the formula (2-9) may be the same or different from each other. "*" it is a bond Shows.) The liquid crystal alignment agent according to claim 1 or 2 , further containing a polymer having no partial structure represented by the formula (1). The liquid crystal alignment agent according to claim 3 , wherein the polymer having no partial structure represented by the formula (1) is at least one polymer selected from the group consisting of polyamic acid and polyimide. The liquid crystal alignment agent according to any one of claims 1 to 4 , which contains at least one selected from the group consisting of a functional silane compound, an acid generator, a base generator and a radical generator. A liquid crystal alignment film formed by using the liquid crystal alignment agent according to any one of claims 1 to 5. A method for producing a liquid crystal alignment film, which comprises forming a coating film using the liquid crystal alignment agent according to any one of claims 1 to 5 and irradiating the coating film with light to impart liquid crystal alignment ability. A liquid crystal element including the liquid crystal alignment film according to claim 6.