JP2022027480A - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal element - Google Patents

Abstract

To provide a liquid crystal alignment agent capable of forming a liquid crystal alignment film excellent in adhesion property between a sealant and a substrate and providing a liquid crystal element hardly generating afterimage.SOLUTION: Liquid crystal alignment agent contains a polymer [A] with partial structure represented by formula (1), a polymer [B] with partial structure represented by formula (2), and a polymer [C] with partial structure X as main chain. In the structure represented by partial structure X:-(CH2)a- or the structure represented by -(CH2)a-, any methylene group is substituted by groups such as -NR7-. In the formula (1), R1 represents protective group. In the formula (2), A1 and A4 each independently represents divalent aromatic ring group. R2 and R3 each independently represents hydrogen atom or monovalent organic group. B1 represents single bond, -NR4-, -O- or divalent aromatic heterocyclic group.SELECTED DRAWING: None

Description

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal element.

As the liquid crystal material of the liquid crystal element, a negative type liquid crystal is used in the liquid crystal element such as VA drive method and MVA drive method, and TN type, IPS (In-Plane Switching) drive method, FFS (Fringe Field Switching) drive method and the like are used. A positive liquid crystal is used in the liquid crystal element. Further, in recent years, it has been proposed to use a negative type liquid crystal in an IPS drive type or FFS drive type liquid crystal element in order to further improve the definition of the liquid crystal element (see, for example, Patent Document 1).

In recent years, liquid crystal elements have been applied to a wide range of applications from relatively large display devices such as liquid crystal televisions and information displays to small display devices such as smartphones. With the widespread use of liquid crystal elements, further improvement in quality of liquid crystal elements is required. Therefore, conventionally, a polymer having a nitrogen-containing metaarylene structure is contained in a liquid crystal alignment agent to obtain a liquid crystal alignment film having a low resistance value and high transparency, and there is little seizure (DC afterimage) due to accumulated charges. It has been proposed to obtain a liquid crystal element (see, for example, Patent Document 2).

In touch panel type display devices such as smartphones and tablet PCs, the frame is narrowed in order to make the operating area of the touch panel wider and the display device smaller. As one of the methods for narrowing the frame, a method is known in which a liquid crystal alignment film is formed on the entire surface of the base material, and then a sealing agent is applied on the liquid crystal alignment film to bond the base materials together (for example). , Patent Document 3).

International Publication No. 2016/152928 International Publication No. 2019/093037 Japanese Unexamined Patent Publication No. 2013-109154

When the sealant is placed on the liquid crystal alignment film for the purpose of narrowing the frame of the liquid crystal element, the sealant portion tends to be easily peeled off from the base material of the liquid crystal alignment film. Therefore, there is a concern that the reliability of the liquid crystal element will decrease.

Further, when an attempt is made to reduce the afterimage of the liquid crystal element by introducing a metaarylene structure into the polymer as in the technique of Patent Document 2, the liquid crystal alignment film is hard due to the structure containing a large amount of aromatic rings derived from the metaarylene structure. It becomes brittle, and there is a concern that the adhesion between the liquid crystal alignment film and the base material (particularly, the adhesion with the base material at the spacer portion) may decrease. On the other hand, it is difficult to simultaneously satisfy a plurality of characteristics such as reduction of afterimage, adhesion to a base material, and adhesion to a sealant, and there is room for further improvement in a liquid crystal alignment agent.

The present invention has been made in view of the above problems, and is a liquid crystal alignment agent capable of forming a liquid crystal alignment film having excellent adhesion to a sealant and a substrate and obtaining a liquid crystal element in which an afterimage is less likely to occur. The main purpose is to provide.

The present inventors have diligently studied in order to solve the above-mentioned problems, and have found that the above-mentioned problems can be solved by using a plurality of polymers having different structures, and have completed the present invention. Specifically, the present invention provides the following means.

（式（１）中、Ｒ^１は保護基である。「＊」は結合手であることを表す。）

（式（２）中、Ａ^１及びＡ^４は、それぞれ独立に２価の芳香環基である。Ｒ^２及びＲ^３は、それぞれ独立に水素原子又は１価の有機基である。Ｂ^１は、単結合、－ＮＲ^４－、－Ｏ－又は２価の芳香族複素環基である。Ｒ^４は、水素原子又は１価の有機基である。Ｂ^１が単結合である場合、Ａ^２は２価の芳香環基であり、Ａ^３は単結合又は２価の芳香環基である。Ｂ^１が２価の芳香族複素環基である場合、Ａ^２及びＡ^３は、それぞれ独立に単結合又は２価の芳香環基である。Ｂ^１が－ＮＲ^４－又は－Ｏ－である場合、Ａ^２及びＡ^３は、それぞれ独立に２価の芳香環基であるか、又は、Ａ^２が有する芳香環とＡ^３が有する芳香環とが単結合又は鎖状構造によって連結されて、－ＮＲ^４－又は－Ｏ－と共に構成される窒素又は酸素含有縮合環構造を表す。「＊」は結合手であることを表す。） <1> A polymer [A] having a partial structure represented by the following formula (1) and not having a partial structure represented by the following formula (2) and a partial structure represented by the following formula (2). A polymer [B] having the following, and a polymer having the following partial structure X in the main chain and not having the partial structure represented by the following formula (1) and the partial structure represented by the following formula (2) [ C] and a liquid crystal alignment agent containing.
Partial structure X: In the structure represented by-(CH ₂ ) _a- (where a is an integer of 2 to 20) or- (CH ₂ ) _a- , any methylene group is-. Selected from the group consisting of NR ^7- , -O-, -COO-, -NR ⁷ -CO-, -NR ⁷ -COO-, -NR ⁸ -CO-NR ^9- and nitrogen-containing non-aromatic heterocyclic groups. A structure (where R ⁷ is a hydrogen atom or an alkyl group; R ⁸ and R ⁹ are independently hydrogen atoms or an alkyl group, respectively, or with R ⁸ ). Represents a ring structure in which R ⁹ is combined with each other and is composed of a nitrogen atom to which R ⁸ is bonded, a nitrogen atom to which R ⁹ is bonded, and -CO-.-NR ^7- , -O-, -COO-,- NR ⁷ -CO-, -NR ⁷ -COO-, -NR ⁸ -CO-NR ^9- and nitrogen-containing non-aromatic heterocyclic groups are not adjacent to each other).

(In equation (1), R ¹ is a protecting group. "*" Indicates a bond.)

(In the formula (2), A ¹ and A ⁴ are independently divalent aromatic ring groups, respectively. R ² and R ³ are independently hydrogen atoms or monovalent organic groups, respectively. B ¹ is. , Single bond, -NR ^4- , -O- or a divalent aromatic heterocyclic group. R ⁴ is a hydrogen atom or a monovalent organic group. If B ¹ is a single bond, A ² Is a divalent aromatic ring group and A ³ is a single-bonded or divalent aromatic ring group. When B ¹ is a divalent aromatic heterocyclic group, A ² and A ³ are independent of each other. It is a single-bonded or divalent aromatic ring group. When B ¹ is -NR ^4- or -O-, A ² and A ³ are independently divalent aromatic ring groups, or A. The aromatic ring of ² and the aromatic ring of A3 ^are connected by a single bond or a chain structure to represent a nitrogen or oxygen-containing fused ring structure composed of -NR ^4- or -O-. Indicates that it is a bond.)

（式（１Ａ）中、「＊」は結合手であることを表す。）
＜４＞ 上記＜２＞又は＜３＞の液晶配向膜を具備する液晶素子。 <2> A liquid crystal alignment film formed by the liquid crystal alignment agent of <1> above.
<3> A polymer having a structural unit containing a partial structure represented by the following formula (1A) in a portion different from the group involved in the polymerization and not having a partial structure represented by the following formula (2). It contains a polymer having a partial structure represented by the following formula (2) and a polymer having the following partial structure X in the main chain and not having the partial structure represented by the following formula (2). , Liquid crystal alignment film.

(In equation (1A), "*" indicates a bond.)
<4> A liquid crystal element provided with the liquid crystal alignment film of <2> or <3>.

According to the liquid crystal alignment agent of the present invention, it is possible to form a liquid crystal alignment film having excellent adhesion to the sealing agent and the substrate, and it is possible to obtain a liquid crystal element in which an afterimage is unlikely to occur. In particular, according to the liquid crystal alignment agent of the present invention, the adhesion between the base material and the liquid crystal alignment film at the spacer arrangement portion can be improved.

The liquid crystal alignment agent of the present disclosure contains a polymer [A], a polymer [B], and a polymer [C], which are three types of polymers having different monomer compositions from each other. Hereinafter, each component contained in the liquid crystal alignment agent of the present disclosure, and other components optionally blended will be described.

In addition, in this specification, a "hydrocarbon group" means 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 only of an aromatic ring structure, and may include a chain structure or an alicyclic hydrocarbon structure as a part thereof. The term "aromatic ring" is meant to include an aromatic hydrocarbon ring and an aromatic heterocycle. The "structural unit" is a unit that mainly constitutes the main chain structure and includes at least two or more units in the main chain structure. Unless otherwise specified, each component and each compound may be used alone or in combination of two or more. The "protecting group" refers to an atomic group that temporarily converts a highly reactive characteristic group (-NH-in the following formula (1)) into an inactive functional group.

（式（１）中、Ｒ^１は保護基である。「＊」は結合手であることを表す。） <Polymer [A]>
The polymer [A] is a polymer having a partial structure represented by the following formula (1).

(In equation (1), R ¹ is a protecting group. "*" Indicates a bond.)

In the above formula (1), the protecting group of R ¹ is preferably a monovalent group desorbed by heat, for example, a carbamate-based protecting group, an amide-based protecting group, an imide-based protecting group, and a sulfonamide-based protecting group. And so on. Of these, R ¹ is preferably a carbamate-based protecting group because of its high heat-removability. Specific examples of the protecting group include tert-butoxycarbonyl group (Boc group), benzyloxycarbonyl group, 1,1-dimethyl-2-haloethyloxycarbonyl group, allyloxycarbonyl group (Allloc group) and 2- (trimethylsilyl group). ) Ethoxycarbonyl group, 9-fluoronylmethyloxycarbonyl group (F-moc group) and the like. Of these, the tert-butoxycarbonyl group is particularly preferable because it has excellent heat-removability, can enhance the effect of improving the adhesion to the sealant, and can reduce the residual amount in the membrane of the deprotected portion. ..

In the above formula (1), one of the two "*" may be bonded to a hydrogen atom. That is, of the two "*" in the above formula (1), one may be bonded to a hydrogen atom and the other may be bonded to a carbon atom. Alternatively, both of the two "*" may be bonded to the carbon atom.

The polymer [A] preferably has the following partial structure Y together with the partial structure represented by the above formula (1). When the polymer [A] further has a partial structure Y, it is preferable in that, in addition to the DC afterimage, it is possible to suppress the generation of an AC afterimage due to the orientation direction of the liquid crystal being deviated from the initial orientation.
Partial structure Y: In the structure represented by-(CH ₂ ) _b- (where b is an integer of 2 to 20) or- (CH ₂ ) _b- , any methylene group is-. Selected from the group consisting of NR ^10- , -O-, -COO-, -NR ¹⁰ -CO-, -NR ¹⁰ -COO-, -NR ¹⁰ -CO-NR ^11- and nitrogen-containing non-aromatic heterocyclic groups. A structure that is replaced by at least one group (where R ¹⁰ and R ¹¹ are independently hydrogen atoms or monovalent organic groups. In the partial structure Y, -NR ^10- , -O-, -COO-, -NR ¹⁰ -CO-, -NR ¹⁰ -COO-, -NR ¹⁰ -CO-NR ^11- and nitrogen-containing aromatic heterocyclic groups are not adjacent to each other).

The b in the partial structure Y is preferably 2 or more, and the partial structure Y may contain a linear alkanediyl group having 2 or more carbon atoms in that the effect of improving the reduction of AC afterimage in the liquid crystal element can be enhanced. More preferred. Further, from the viewpoint of suppressing the decrease in film strength, b is preferably 12 or less, more preferably 10 or less.
When R ¹⁰ and R ¹¹ are monovalent organic groups, the monovalent organic group is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms or a protecting group. The monovalent hydrocarbon group is preferably an alkyl group having 1 to 3 carbon atoms or a phenyl group, and more preferably an alkyl group having 1 to 3 carbon atoms. The above description of ^R1 can be incorporated as an example and a preferred example of the protecting group.
Of the above, R ¹⁰ and R ¹¹ are preferably hydrogen atoms, alkyl groups having 1 to 3 carbon atoms, or tert-butoxycarbonyl groups.
Examples of the nitrogen-containing non-aromatic heterocyclic group include a piperidine-1,4-diyl group, a piperazine-1,4-diyl group and the like.

The polymer [A] may have a partial structure represented by the above formula (1) separately from the partial structure Y, or the partial structure represented by the above formula (1) may be contained in the partial structure Y. You may have. When the partial structure represented by the above formula (1) is contained in the partial structure Y, the polymer [A] has an arbitrary methylene group as the partial structure Y in the structure represented by-(CH ₂ ) _b- . , -NR ^10- , -NR ^{10-CO-, -NR 10-COO-, and -NR 10 - CO} -NR ¹¹ -replaced by at least one group selected from the group. It also has a structure in which at least one of R ¹⁰ and R ¹¹ is a protecting group. When the partial structure Y has a structure having a protecting group, by using the monomer having the partial structure Y in the production of the polymer [A], it is possible to improve the adhesion to the sealant and reduce the AC afterimage at the same time. Preferred in terms of points. It is preferable that the polymer [A] has a partial structure Y in the main chain in that the effect of improving the AC afterimage reduction of the liquid crystal element can be enhanced. The polymer [A] does not have the partial structure represented by the following formula (2) that the polymer [B] has.

In the present specification, another polymer "has" a partial structure (hereinafter referred to as "specific structure") possessed by at least one of the plurality of polymers contained in the liquid crystal aligning agent. "No" means that it is permissible for another polymer to have that particular structure to the extent that it does not impair the effectiveness of the invention. When another polymer does not have a specific structure, the content of the specific structure in the other polymer is preferably 1 mol% or less, more preferably 0, with respect to the total structural units of the other polymer. It is 5.5 mol% or less, more preferably 0.1 mol or less (the same applies to the polymer [B] and the polymer [C]).

The main chain of the polymer [A] is not particularly limited, but the partial structure represented by the above formula (1) is capable of forming a highly reliable liquid crystal alignment film having high affinity with liquid crystal and mechanical strength. The polymer [A] is preferably at least one selected from the group consisting of polyamic acids, polyamic acid esters and polyimides in that the polymer [A] can be easily introduced into the polymer.

The method for producing the polymer [A] is not particularly limited, and the polymer [A] can be produced according to a conventional method of organic chemistry. Specifically, for example, a method of polymerizing using a monomer having a partial structure represented by the above formula (1); a reaction between a polymer terminal and a compound having a partial structure represented by the above formula (1). Then, a method of introducing the partial structure represented by the above formula (1) into the polymer terminal and the like can be mentioned. Among these, the polymer [A] is produced by polymerization using a monomer having a partial structure represented by the above formula (1) in that the effect of improving the adhesion between the liquid crystal alignment film and the sealant can be further enhanced. It is preferable to do so. That is, the polymer [A] is preferably a polymer having a structural unit derived from a monomer having a partial structure represented by the above formula (1).

The "main chain" refers to the part of the "stem" consisting of the longest chain of atoms in the polymer. It is permissible for this "stem" portion to contain a ring structure. For example, "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. The "side chain" means a portion branched from the "stem" of the polymer.

(Polyamic acid)
When the polymer [A] is a polyamic acid, the polyamic acid (hereinafter, also referred to as “polyamic acid [A]”) has a high degree of freedom in selecting a monomer, and has a partial structure represented by the above formula (1). Is easily introduced, the tetracarboxylic acid dianhydride is reacted with a diamine compound containing a diamine having a partial structure represented by the above formula (1) (hereinafter, also referred to as “specific diamine (A)”). It is preferable to produce by the method of causing.

-Tetracarboxylic acid dianhydride As the tetracarboxylic acid dianhydride used for the synthesis of polyamic acid [A], for example, aliphatic tetracarboxylic acid dianhydride, alicyclic tetracarboxylic acid dianhydride, aromatic tetracarboxylic Acid dianhydride and the like can be mentioned. Specific examples of these include 1,2,3,4-butanetetracarboxylic acid dianhydride, ethylenediamine tetraacetichydride dianhydride and the like as aliphatic tetracarboxylic acid dianhydride; alicyclic tetracarboxylic acid dianhydride. 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentyl Dianhydride, 5- (2,5-dioxotetratetra-3-yl) -3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 5- (2) , 5-Dioxotetrahydride-3-yl) -8-methyl-3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 2,4,6,8-tetra Carboxybicyclo [3.3.0] octane-2: 4,6: 8-anhydride, cyclopentanetetracarboxylic acid dianhydride, cyclohexanetetracarboxylic acid dianhydride, etc .; aromatic tetracarboxylic acid dianhydride, etc. As, pyromellitic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride, 4,4'-(hexafluoroisopropylidene) diphthalic anhydride, ethylene glycol bisanhydrotrimate. , 4,4'-(hexafluoroisopropylidene) diphthalic acid anhydride, 4,4'-carbonyldiphthalic acid anhydride, etc .; Acid dianhydride can be used.

The tetracarboxylic dianhydride used for the synthesis of the polyamic acid [A] is an alicyclic tetracarboxylic dianhydride in that it has high solubility in a solution and can obtain a liquid crystal alignment film exhibiting low afterimage characteristics. It is preferable to include. The ratio of the alicyclic tetracarboxylic dianhydride used is preferably 20 mol% or more, preferably 40 mol% or more, based on the total amount of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid [A]. Is more preferable, and 50 mol% or more is further preferable.

（式（１－１）中、Ａ^７及びＡ^８は、それぞれ独立に２価の芳香環基である。Ｙ^１は２価の有機基である。ｒは０又は１である。ただし、ｒが１の場合、Ａ^７、Ａ^８及びＹ^１のうち少なくともいずれかは、上記式（１）で表される部分構造を有する。ｒが０の場合、Ａ^７は、上記式（１）で表される部分構造を有する。） -Diamine compound The specific diamine (A) used for the synthesis of the polymer [A] is preferably a compound represented by the following formula (1-1).

(In the formula (1-1), A ⁷ and A ⁸ are independently divalent aromatic ring groups. Y ¹ is a divalent organic group. R is 0 or 1, but r. When 1, at least one of A ⁷ , A ⁸ and Y ¹ has a partial structure represented by the above formula (1). When r is 0, A ⁷ has the above formula (1). It has a partial structure represented.)

^In the above formula ⁽ 1-1), examples of the divalent aromatic ring group of A7 and A8 include a divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group. A ⁷ and A ⁸ may have a substituent on the aromatic ring moiety. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a halogen atom, a monovalent group having a partial structure represented by the above formula (1), and the like.

As a preferable specific example of ^A7 and ^A8 , any two hydrogen atoms bonded to the carbon atoms constituting the ring of the benzene ring, the naphthalene ring or the anthracene ring are removed as the divalent aromatic hydrocarbon group. A group consisting of a divalent aromatic heterocyclic group obtained by removing any two hydrogen atoms bonded to carbon atoms constituting a pyridine ring, a pyrimidine ring, a pyridazine ring, or a pyrazine ring, respectively. Can be mentioned. Of these, ^A7 and ^A8 are preferably substituted or unsubstituted phenylene group, biphenylene group or pyridinylene group.

As the divalent organic group of Y ¹ , any methylene group in the structure represented by-(CH ₂ ) _b -and the structure represented by-(CH ₂ ) _b- can be -NR ^10- , -O. -, -COO-, -NR ¹⁰ -CO-, -NR ¹⁰ -COO-, -NR ¹⁰ -CO-NR ^11- and at least one group selected from the group consisting of nitrogen-containing non-aromatic heterocyclic groups. Examples thereof include a structure substituted with -NR ^10- , -NR ¹⁰ -CO-, -NR ¹⁰ -COO-, -NR ¹⁰ -CO-NR ^11- , and the like. Of these, Y ¹ has any methylene group in the structure represented by-(CH ₂ ) _b- , which is -NR ^10- , -NR ¹⁰ -CO-, -NR ¹⁰ -COO- and -NR ^10- . It is preferable that the structure is replaced with at least one group selected from the group consisting of CO-NR ^11- . When both R ¹⁰ and R ¹¹ are different groups from the protecting group, at least one of A ⁷ and A ⁸ is represented by the above formula (1) as a substituent introduced into the aromatic ring. It is preferable to have a partial structure. Note that Y ¹ does not have an aromatic ring group.
r is 0 or 1, with 1 being more preferred.

（式中、「Ｂｏｃ」は、ｔｅｒｔ－ブトキシカルボニル基を表す。「Ａｌｌｏｃ」は、アリルオキシカルボニル基を表す。「Ｆ－ｍｏｃ」は、９－フルオロニルメチルオキシカルボニル基を表す。） Specific examples of the specific diamine (A) include compounds represented by the following formulas (DA-1) to (DA-12).

(In the formula, "Boc" represents a tert-butoxycarbonyl group. "Allloc" represents an allyloxycarbonyl group. "F-moc" represents a 9-fluoronylmethyloxycarbonyl group.)

Of the above, the specific diamine (A) is preferably a compound represented by each of the above formulas (DA-1) to (DA-10), and the above formulas (DA-1) and (DA-3) to (DA-3) to The compounds represented by the formulas (DA-6) and (DA-8) are more preferable.

The diamine compound used for the synthesis of the polyamic acid [A] may be only the specific diamine (A), but together with the specific diamine (A), a diamine different from the specific diamine (A) (hereinafter, "other diamines"). (A) ”) may be used. Examples of the other diamine (A) include aliphatic diamines, alicyclic diamines, aromatic diamines, diaminoorganosiloxanes and the like. Specific examples of other diamines (A) include 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 1,5-bis (4-aminophenoxy) pentane, and 1,2-bis (4). -Aminophenoxy) ethane, 1,3-bis (4-aminophenoxy) propane, 1,6-bis (4-aminophenoxy) hexane, 6,6'-(pentamethylenedioxy) bis (3-aminopyridine) Partial structures such as 4,'-(2- (4-aminophenoxy) ethoxy)-[1,1'-biphenyl] -4-amine, 1,3-bis (3-aminopropyl) -tetramethyldisiloxane, etc. Diamine compound having Y in the main chain;
o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4-aminophenyl-4-aminobenzoate, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 4 , 4'-diaminodiphenyl ether, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,5-diamino-N, N-bis (pyridine-3-ylmethyl) benzamide, etc. Examples thereof include diamine compounds which are not contained in.

In the synthesis of the polyamic acid [A], the amount of the specific diamine (A) used should be the total amount of the diamine compound used in the synthesis of the polyamic acid [A] from the viewpoint of sufficiently obtaining the effect of improving the adhesion with the sealant. On the other hand, it is preferably 10 mol% or more, more preferably 20 mol% or more, further preferably 25 mol% or more, and particularly preferably 35 mol% or more.
Further, the amount of the diamine having the partial structure Y used (however, when the specific diamine (A) has the partial structure Y, the partial structure Y of the specific diamine (A) and the other diamines (A) is the main chain. The total amount of the diamine compound and the diamine compound contained in the above is 10 mol% or more based on the total amount of the diamine compound used for the synthesis of the polyamic acid [A] from the viewpoint of sufficiently obtaining the effect of improving the reduction of AC afterimage. It is preferably 20 mol% or more, more preferably 30 mol% or more, and particularly preferably 40 mol% or more.

-Synthesis of polyamic acid The polyamic acid [A] can be obtained by reacting a tetracarboxylic dianhydride and a diamine compound with a molecular weight adjusting agent, if necessary. In the polyamic acid synthesis reaction, the ratio of the tetracarboxylic acid dianhydride to the diamine compound is 0.2 to 2 for the acid anhydride group of the tetracarboxylic acid dianhydride with respect to 1 equivalent of the amino group of the diamine compound. The equivalent ratio is preferable. Examples of the molecular weight adjusting agent include acid monoanhydrides such as maleic anhydride, phthalic anhydride and itaconic anhydride, monoamine compounds such as aniline, cyclohexylamine and n-butylamine, and monoisocyanate compounds such as phenylisocyanate and naphthylisocyanate. Can be mentioned. The proportion of the molecular weight adjusting agent used is preferably 20 parts by mass or less with respect to 100 parts by mass in total of the tetracarboxylic dianhydride and the diamine compound used.

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. Examples of the organic solvent used in the reaction include an aprotonic polar solvent, a phenol solvent, an alcohol solvent, a ketone solvent, an ester solvent, an ether solvent, a halogenated hydrocarbon, and a hydrocarbon. Specific examples of these include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, and the like. One or more selected from the group consisting of xylenol and halogenated phenol is used as a reaction solvent, or a mixture of one or more of these with another organic solvent (for example, butyl cellosolve, diethylene glycol diethyl ether, etc.) is used. Is preferable. The amount (a) of the organic solvent used shall be such that the total amount (b) of the tetracarboxylic dianhydride and the diamine is 0.1 to 50% by mass with respect to the total amount (a + b) of the reaction solution. Is preferable.

As described above, a polymer solution obtained by dissolving the polyamic acid [A] is obtained. This polymer solution may be used as it is for the preparation of the liquid crystal alignment agent, or the polyamic acid [A] contained in the polymer solution may be isolated and then used for the preparation of the liquid crystal alignment agent.

(Polyamic acid ester)
When the polymer [A] is a polyamic acid ester, the polyamic acid ester is, for example, a method for reacting [I] polyamic acid [A] with an esterifying agent, [II] tetracarboxylic acid diester, and a specific diamine. It can be obtained by a method of reacting with a diamine compound containing (A), a method of reacting [III] a tetracarboxylic acid diester dihalide with a diamine compound containing a specific diamine (A), or the like. 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 reaction solution obtained by dissolving the polyamic acid ester 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. In addition, in this specification, "tetracarboxylic acid derivative" means containing tetracarboxylic acid dianhydride, tetracarboxylic acid diester and tetracarboxylic acid diester dihalide.

(Polyimide)
When the polymer [A] is a polyimide, the polyimide can be obtained, for example, by dehydrating and ring-closing the polyamic acid [A] 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, and only a part of the amic acid structure is dehydrated and ring-closed to form an amic acid structure and an imide. It may be a partially imidized product in which a ring structure coexists. The imidization ratio of the polyimide is preferably 20 to 99%, more preferably 30 to 90%. The imidization ratio is the ratio of the number of imide ring structures to the total number of amic acid structures and the number of imide ring structures of polyimide expressed as a percentage. 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 dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to this solution, and heating as necessary. In this method, as the dehydrating agent, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably 0.01 to 20 mol per 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 for the dehydration ring closure reaction include organic solvents exemplified as those used for the synthesis of polyamic acid. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C. The reaction time is preferably 1.0 to 120 hours. The reaction solution containing the polyimide may be used as it is for the preparation of the liquid crystal alignment agent, or the polyimide may be isolated and then used for the preparation of the liquid crystal alignment agent.

（式（２）中、Ａ^１及びＡ^４は、それぞれ独立に２価の芳香環基である。Ｒ^２及びＲ^３は、それぞれ独立に水素原子又は１価の有機基である。Ｂ^１は、単結合、－ＮＲ^４－、－Ｏ－又は２価の芳香族複素環基である。Ｒ^４は、水素原子又は１価の有機基である。Ｂ^１が単結合である場合、Ａ^２は２価の芳香環基であり、Ａ^３は単結合又は２価の芳香環基である。Ｂ^１が２価の芳香族複素環基である場合、Ａ^２及びＡ^３は、それぞれ独立に単結合又は２価の芳香環基である。Ｂ^１が－ＮＲ^４－又は－Ｏ－である場合、Ａ^２及びＡ^３は、それぞれ独立に２価の芳香環基であるか、又は、Ａ^２が有する芳香環とＡ^３が有する芳香環とが単結合又は鎖状構造によって連結されて、－ＮＲ^４－又は－Ｏ－と共に構成される窒素又は酸素含有縮合環構造を表す。「＊」は結合手であることを表す。） <Polymer [B]>
The polymer [B] is a polymer having a partial structure represented by the following formula (2).

(In the formula (2), A ¹ and A ⁴ are independently divalent aromatic ring groups, respectively. R ² and R ³ are independently hydrogen atoms or monovalent organic groups, respectively. B ¹ is. , Single bond, -NR ^4- , -O- or a divalent aromatic heterocyclic group. R ⁴ is a hydrogen atom or a monovalent organic group. If B ¹ is a single bond, A ² Is a divalent aromatic ring group and A ³ is a single-bonded or divalent aromatic ring group. When B ¹ is a divalent aromatic heterocyclic group, A ² and A ³ are independent of each other. It is a single-bonded or divalent aromatic ring group. When B ¹ is -NR ^4- or -O-, A ² and A ³ are independently divalent aromatic ring groups, or A. The aromatic ring of ² and the aromatic ring of A3 ^are connected by a single bond or a chain structure to represent a nitrogen or oxygen-containing fused ring structure composed of -NR ^4- or -O-. Indicates that it is a bond.)

In the above formula (2), examples of the divalent aromatic ring group of A ¹ and A ⁴ include a divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group. A ¹ and A ⁴ may have a substituent on the aromatic ring portion. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a halogen atom and the like. As a preferable specific example of A ¹ and A ⁴ , any two hydrogen atoms bonded to the carbon atoms constituting the ring of the benzene ring, the naphthalene ring or the anthracene ring are removed as the divalent aromatic hydrocarbon group. A group consisting of a divalent aromatic heterocyclic group obtained by removing any two hydrogen atoms bonded to carbon atoms constituting a pyridine ring, a pyrimidine ring, a pyridazine ring, or a pyrazine ring, respectively. Can be mentioned. Of these, A ¹ and A ⁴ are preferably a phenylene group, a biphenylene group or a pyridinylene group, and a phenylene group is particularly preferable.

For R ² and R ³ , the monovalent organic group is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms or a protecting group. The monovalent hydrocarbon group is preferably an alkyl group having 1 to 3 carbon atoms or a phenyl group, and more preferably an alkyl group having 1 to 3 carbon atoms. The above description of ^R1 can be incorporated as an example and a preferred example of the protecting group.
Of these, R ² and R ³ are preferably hydrogen atoms or monovalent hydrocarbon groups having 1 to 10 carbon atoms, and more preferably hydrogen atoms or alkyl groups having 1 to 3 carbon atoms.

B ¹ is a single bond, -NR ^4- , -O- or a divalent aromatic heterocyclic group. The divalent aromatic heterocyclic group is a group obtained by removing any two hydrogen atoms from a pyridine ring, a pyrimidine ring, a pyridazine ring or a pyrazine ring; and a group obtained by removing any two hydrogen atoms from a furan ring. Group: A group obtained by removing any two hydrogen atoms from the thiophene ring, and the like. Of these, a group obtained by removing any two hydrogen atoms from the pyrrole ring, a furan ring and a thiophene ring is preferable, and a group obtained by removing any two hydrogen atoms from the pyrrole ring. More preferred.

The monovalent organic group of ^R4 is preferably an alkyl group having 1 to 3 carbon atoms or a phenyl group, and more preferably an alkyl group having 1 to 3 carbon atoms.

When B ¹ is a single bond or a divalent aromatic heterocyclic group, A ² and A ³ are divalent aromatic ring groups, respectively. For examples and preferred examples of the divalent aromatic ring group, the description of the divalent aromatic ring group of A ¹ and A ⁴ can be incorporated.

When B ¹ is -NR ⁴ -or -O-, the description of the divalent aromatic ring group of A ¹ and A ⁴ can be incorporated as the divalent aromatic ring group of A ² and A ³ . .. A ² and A ³ are composed of a nitrogen-containing condensation in which the aromatic ring of A ² and the aromatic ring of A ³ are linked by a single bond or a chain structure (for example, an ethylene group) together with -NR ^4- . When representing a ring structure, examples of the fused ring structure include a carbazole structure, a 9-methylcarbazole structure, a 9-ethylcarbazole structure and the like. A ² and A ³ are oxygen-containing fused rings in which the aromatic ring of A ² and the aromatic ring of A ³ are linked by a single bond or a chain structure (for example, an ethylene group) and formed together with —O—. When representing a structure, examples of the fused ring structure include a dibenzofuran structure and the like.

The partial structure represented by the above formula (2) has a total of 3 or more aromatic rings (including an aromatic hydrocarbon ring and an aromatic heterocycle), and it is particularly preferable to have 4 or more aromatic rings. When the partial structure represented by the above equation (2) contains a total of four or more aromatic rings, the longer the conjugated structure makes the relaxation of the residual charge faster, and the afterimage (particularly the DC afterimage) can be sufficiently reduced. Is suitable. Among these, it is particularly preferable that the partial structure represented by the above formula (2) has a biphenyl structure.

The main chain of the polymer [B] is not particularly limited, and can be appropriately selected depending on the main chain of the polymer [A] and the like. When the polymer [A] is at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, the polymer [B] can have a high affinity with the polymer [A]. It is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide.

(Polyamic acid)
When the polymer [B] is a polyamic acid, the polyamic acid (hereinafter, also referred to as “polyamic acid [B]”) can easily introduce the partial structure represented by the above formula (2) into the polymer. It is obtained by reacting a tetracarboxylic acid dianhydride with a diamine compound containing a diamine having a partial structure represented by the above formula (2) (hereinafter, also referred to as "specific diamine (B)"). It is preferably a polymer. Examples of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid [B] include compounds exemplified as an anhydride for the tetracarboxylic dianhydride used for the synthesis of the polyamic acid [A]. The tetracarboxylic dianhydride used for the synthesis of the polyamic acid [B] preferably contains an alicyclic tetracarboxylic dianhydride. For the explanation of the amount of the alicyclic tetracarboxylic dianhydride used, the explanation of the polyamic acid [A] can be incorporated.

（式（２－１）中、Ａ^１～Ａ^４、Ｂ^１、Ｒ^２及びＲ^３は、それぞれ上記式（２）と同義である。） The specific diamine (B) used for the synthesis of the polymer [B] is preferably a compound represented by the following formula (2-1).

(In the formula (2-1), A ¹ to A ⁴ , B ¹ , R ² and R ³ are synonymous with the above formula (2), respectively.)

Specific examples of the specific diamine (B) include compounds represented by the following formulas (DA-19) to (DA-27), formulas (DA-42) and formulas (DA-43). ..

Of the above, the specific diamine (B) is preferably a compound represented by each of the above formulas (DA-19) to (DA-25) and the above formula (DA-42), and the above formulas (DA-19) to The compounds represented by the formulas (DA-23) and (DA-42) are more preferable, and the compounds represented by the above formulas (DA-19) to (DA-21) are further preferable.

The diamine compound used for the synthesis of the polyamic acid [B] may be only the specific diamine (B), but together with the specific diamine (B), a diamine different from the specific diamine (B) (hereinafter, "other diamines"). (B) ”) may be used. Examples of other diamines (B) include aliphatic diamines, alicyclic diamines, aromatic diamines and the like. Specific examples of the other diamine (B) include diamine compounds having no partial structure Y in the main chain, which are exemplified in the description of the polymer [A]. The polymer [B] preferably has neither the partial structure Y nor the partial structure X described below.

The amount of the specific diamine (B) used in the synthesis of the polymer [B] is the same as that of the diamine compound used in the synthesis of the polymer [B] in that the afterimage (particularly the DC afterimage) can be sufficiently reduced. It is preferably 2 mol% or more, more preferably 5 mol% or more, still more preferably 10 mol% or more, based on the total amount. Further, the amount of the specific diamine (B) used can be arbitrarily set in the range of 100 mol% or less with respect to the total amount of the diamine compound used for the synthesis of the polymer [B]. It is preferably 95 mol% or less, more preferably 90 mol% or less, still more preferably 80 mol% or less, in that the coating property of the liquid crystal alignment agent on the substrate can be improved.

The polyamic acid [B], the polyamic acid ester, and the polyimide as the polymer [B] can also be produced in the same manner as the polymer [A]. As for various conditions and the like in the method for synthesizing each polymer such as polyamic acid [B], the above-mentioned description of the polymer [A] can be incorporated.

<Polymer [C]>
The polymer [C] is a polymer having the following partial structure X in the main chain. By including the polymer [C] having a partial structure X together with the polymer [A] and the polymer [B] in the liquid crystal alignment agent, the adhesion to the sealing agent is improved and the afterimage (AC afterimage and DC afterimage) is improved. It is preferable in that the adhesion between the liquid crystal alignment film and the base material (particularly, the adhesion to the base material at the spacer portion) can be improved while reducing the amount.
Partial structure X: In the structure represented by-(CH ₂ ) _a- (where a is an integer of 2 to 20) or- (CH ₂ ) _a- , any methylene group is-. Selected from the group consisting of NR ^7- , -O-, -COO-, -NR ⁷ -CO-, -NR ⁷ -COO-, -NR ⁸ -CO-NR ^9- and nitrogen-containing non-aromatic heterocyclic groups. A structure that is replaced by at least one group (where R ⁷ is a hydrogen atom or an alkyl group; R ⁸ and R ⁹ are independently hydrogen atoms or alkyl groups, respectively, or with R ⁸ ). Represents a ring structure in which R ⁹ is combined with each other and is composed of a nitrogen atom to which R ⁸ is bonded, a nitrogen atom to which R ⁹ is bonded, and -CO-. In the partial structure X, -NR ^7- , -O-, -COO-, -NR ⁷ -CO-, -NR ⁷ -COO-, -NR ⁸ -CO-NR ^9- and nitrogen-containing non-aromatic heterocyclic groups are not adjacent to each other).

In the partial structure X, it is preferable that the partial structure X contains a linear alkanediyl group having 2 or more carbon atoms, because the effect of improving the adhesion between the base material and the liquid crystal alignment film in the spacer arrangement portion is high. Further, from the viewpoint of suppressing the decrease in film strength, a is preferably 12 or less, more preferably 10 or less.

For R ⁷ , R ⁸ and R ⁹ , a hydrogen atom or a methyl group is preferable, and a hydrogen atom is more preferable. Examples of the ring structure in which R ⁸ and R ⁹ are combined with each other include 2-oxo-4-imidazolidinone-1,3-diyl groups and the like. Examples of the nitrogen-containing non-aromatic heterocyclic group include a piperidine-1,4-diyl group, a piperazine-1,4-diyl group and the like. The polymer [C] does not have the partial structure represented by the above formula (1) and the partial structure represented by the above formula (2).

The partial structure X has at least one group selected from the group consisting of -COO-, -NR ⁷ -CO-, -NR ⁷ -COO- and -NR ⁸ -CO-NR ^9- . It is preferably a structure. Since the partial structure X has such a hydrogen-bonding functional group, it tends to be easily layer-separated from the polymer [A], and is preferable in that the adhesion between the liquid crystal alignment film and the substrate can be further improved. Is. In particular, the partial structure X has at least one group selected from the group consisting of -COO-, -NR ⁷ -CO-, -NR ⁷ -COO- and -NR ⁸ -CO-NR ^9- and the number of carbon atoms. It is preferable to include two or more linear alkanediyl groups because the effect of improving the adhesion to the substrate can be enhanced.

The main chain of the polymer [C] is not particularly limited, but when the polymer [A] is at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, the affinity with the polymer [A]. Similarly, the polymer [C] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide in that the property can be enhanced and the partial structure X can be easily introduced into the main chain of the polymer. Is preferable.

When the polymer [C] is a polyamic acid, the polyamic acid (hereinafter, also referred to as “polyamic acid [C”) is a tetracarboxylic acid diamine in that the partial structure X can be easily introduced into the main chain of the polymer. It is preferably a polymer obtained by reacting an anhydride with a diamine compound containing a diamine having a partial structure X (hereinafter, also referred to as “specific diamine (C)”). Examples of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid [C] include compounds exemplified as an anhydride for the tetracarboxylic dianhydride used for the synthesis of the polyamic acid [A]. The tetracarboxylic dianhydride used for the synthesis of the polyamic acid [C] preferably contains an alicyclic tetracarboxylic dianhydride. For the explanation of the amount of the alicyclic tetracarboxylic dianhydride used, the explanation of the polyamic acid [A] can be incorporated.

（式（３－１）中、Ａ^５は、２価の芳香環基である。Ａ^６は、単結合又は２価の芳香環基である。Ｙ^２は、部分構造Ｘを有する２価の基である。Ｒ^５は、水素原子又は１価の有機基である。） The specific diamine (C) is not particularly limited as long as it is a diamine compound having a partial structure X, and examples thereof include aliphatic diamines, alicyclic diamines, and aromatic diamines. The specific diamine (C) is preferably a compound represented by the following formula (3-1).

(In formula (3-1), A ⁵ is a divalent aromatic ring group. A ⁶ is a single bond or a divalent aromatic ring group. Y ² is a divalent aromatic ring group having a partial structure X. Group. ^R5 is a hydrogen atom or a monovalent organic group.)

In the above formula (3-1), examples of the divalent aromatic ring group of A ⁵ and A ⁶ include a divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group. For specific examples and preferable examples of the divalent aromatic ring groups of A ⁵ and A ⁶ , the description of the divalent aromatic ring groups of A ¹ and A ⁴ in the above formula (2) can be incorporated.

Examples of the monovalent organic group of R ⁵ include a monovalent hydrocarbon group having 1 to 10 carbon atoms. R5 is preferably a hydrogen atom or an alkyl group having 1 to ³ carbon atoms, and more preferably a hydrogen atom or a methyl group.

Y ² is a divalent group having a partial structure X, for example, in the structure represented by-(CH _{2) a-or-(CH 2 ) a- , any} methylene group is -NR ^7- , At least one selected from the group consisting of -O-, -COO-, -NR ⁷ -CO-, -NR ⁷ -COO-, -NR ⁸ -CO-NR ^9- and a nitrogen-containing non-aromatic heterocyclic group. At least one of a divalent group (hereinafter, also referred to as “heteroatom-containing group (c)”),-(CH ₂ ) _a- , and a heteroatom-containing group (c), which are replaced with, is one or more. , A divalent group formed by bonding with a cycloalkylene group (preferably a cyclohexylene group) and the like. Note that Y ² does not have an aromatic ring group.

Specific examples of the specific diamine (C) include metaxylylenediamine, pentamethylenediamine, hexamethylenediamine and the like as the aliphatic diamine; 4,4'-methylenebis (cyclohexylamine) and the like as the alicyclic diamine; As aromatic diamines, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 1,3-bis (4-aminophenethyl) urea, 1,3-bis (4-aminobenzyl) urea, 1 , 5-bis (4-aminophenoxy) pentane, 1,4-bis (4-aminophenoxy) butane, 1,3-bis (4-aminophenoxy) propane, 1,6-bis (4-aminophenoxy) hexane , Bis [2- (4-aminophenyl) ethyl] hexanedioic acid, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 4,4'-[4,4'-propane-1, 3-Diylbis (piperidine-1,4-diyl)] Dianiline, diethyleneglycolbis (4-aminophenyl) ether, compounds represented by the following formulas (DA-32) to (DA-40), etc. are listed. Can be done.

The specific diamine (C) is represented by each of the above formulas (DA-32) to (DA-35) among the compounds represented by the above formulas (DA-32) to (DA-40). The compounds represented by the above formulas (DA-32) to (DA-34) are more preferable.

The diamine compound used for the synthesis of the polyamic acid [C] may be only the specific diamine (C), but together with the specific diamine (C), a diamine different from the specific diamine (C) (hereinafter, "other diamines"). (C) ”) may also be used. Examples of the other diamine (C) include diamines different from the specific diamines (A) to (C), and for example, the main chain does not have the partial structure Y exemplified in the description of the polymer [A]. Diamine compounds and the like can be mentioned.

In synthesizing the polymer [C], the amount of the specific diamine (C) used is relative to the total amount of the diamine compound used in the synthesis of the polymer [C] from the viewpoint of sufficiently increasing the adhesion to the substrate. It is preferably 10 mol% or more, more preferably 20 mol% or more, still more preferably 30 mol% or more. Further, the amount of the specific diamine (C) used can be arbitrarily set in the range of 100 mol% or less with respect to the total amount of the diamine compound used for the synthesis of the polymer [C].

The polyamic acid [C], the polyamic acid ester, and the polyimide as the polymer [C] can also be produced in the same manner as the polymer [A]. As for various conditions and the like in the method for synthesizing each polymer such as polyamic acid [C], the above-mentioned description of the polymer [A] can be incorporated.

For each of the polymers [A], polymer [B] and polymer [C] used to prepare the liquid crystal aligning agent, the solution viscosity of the polymer is 10 to 10 when a solution having a concentration of 10% by mass is used. It is preferably one having a solution viscosity of 800 mPa · s, and more preferably one having a solution viscosity of 15 to 500 mPa · s. The solution viscosity (mPa · s) is the E-type rotational viscosity for a polymer solution having a concentration of 10% by mass prepared using a good solvent for the polymer (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). It is a value measured at 25 ° C. using a meter.

For each of the polymer [A], the polymer [B] and the polymer [C], the polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) is preferably 1,000 to 500. It is 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.

In the liquid crystal alignment agent, the content of the polymer [A] is 1% by mass or more with respect to the total amount of the polymer components contained in the liquid crystal alignment agent from the viewpoint of sufficiently obtaining the effect of improving the adhesion to the sealant. It is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. The content of the polymer [A] is preferably 70% by mass or less, more preferably 60% by mass or less, and 50% by mass, based on the total amount of the polymer components contained in the liquid crystal alignment agent. It is more preferably% or less.

The content of the polymer [B] is preferably 2% by mass or more with respect to the total amount of the polymer components contained in the liquid crystal alignment agent, in that the effect of reducing afterimages (particularly DC afterimages) can be enhanced. It is more preferably 5% by mass or more, and further preferably 10% by mass or more. Further, the content of the polymer [B] is preferably 90% by mass or less, preferably 90% by mass or less, based on the total amount of the polymer components contained in the liquid crystal alignment agent, from the viewpoint of improving the coatability of the liquid crystal alignment agent. It is more preferably 70% by mass or less, and further preferably 70% by mass or less.

The content of the polymer [C] is preferably 2% by mass or more with respect to the total amount of the polymer components contained in the liquid crystal alignment agent in terms of enhancing the effect of improving the adhesion to the substrate. It is more preferably mass% or more, and further preferably 10 mass% or more. Further, the content of the polymer [B] is preferably 80% by mass or less, preferably 80% by mass or less, based on the total amount of the polymer components contained in the liquid crystal alignment agent, from the viewpoint of improving the coatability of the liquid crystal alignment agent. It is more preferably 0% by mass or less, and further preferably 60% by mass or less.

Here, it is considered that the polymer [A] is hydrophobized by protecting the -NH- group, so that it tends to be unevenly distributed on the film surface when the liquid crystal alignment agent is applied on the substrate. Be done. Further, regarding -NR ^1- possessed by the polymer [A], it is considered that the protecting group (R ¹ ) is desorbed and replaced with a hydrogen atom by, for example, post-baking at the time of film formation, whereby a polar functional group appears. Therefore, the liquid crystal alignment agent containing the polymer [A] has high solubility in a solvent at the time of film formation, the polymer [A] tends to be unevenly distributed on the surface layer, and the protecting group is removed after the film formation. It is considered that the adhesion to the sealing agent is improved, and even when the sealing agent is formed on the surface of the liquid crystal alignment film, peeling is unlikely to occur, and a highly reliable liquid crystal element can be obtained.

Further, in order to further improve the performance of the liquid crystal element, the polymer [B] having a specific nitrogen-containing conjugated structure represented by the above formula (2) is blended with the polymer [A] into the liquid crystal alignment agent. Therefore, it is considered that the effect of reducing the DC afterimage is exhibited. However, the partial structure represented by the above formula (2) has many aromatic rings, and the toughness of the formed liquid crystal alignment film (particularly the lower layer portion) is lowered, so that the liquid crystal alignment film is based on, for example, when an external force is applied. It is considered that the adhesiveness between the liquid crystal alignment film and the base material is poor because it is easily peeled off from the material, and in particular, the adhesion between the base material and the liquid crystal alignment film at the spacer arrangement portion is poor.

On the other hand, by using a liquid crystal alignment agent containing the polymer [C] together with the polymer [A] and the polymer [B], the adhesion to the sealant and the effect of reducing the DC afterimage are excellent. It is presumed that the liquid crystal alignment film having excellent adhesion to the substrate (particularly the spacer portion) could be formed.

<Other ingredients>
The liquid crystal alignment agent is different from the polymer [A], the polymer [B], the polymer [C], and, if necessary, the polymer [A], the polymer [B], and the polymer [C]. It may contain a component (hereinafter, also referred to as "other component").

(Other polymers)
The liquid crystal alignment agent of the present disclosure contains a polymer different from the polymer [A], the polymer [B] and the polymer [C] (hereinafter, also referred to as "another polymer") as a polymer component. May be. The main skeleton of other polymers is not particularly limited. Examples of other polymers include polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamideimide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, (meth). ) Acrylic polymer, styrene polymer, maleimide polymer, or styrene-maleimide polymer can be mentioned. From the viewpoint of having high affinity with the liquid crystal when used in combination with the polymer [A], the polymer [B] and the polymer [C], and increasing the reliability of the liquid crystal element, other polymers are polyamic acids. , At least one selected from the group consisting of polyamic acid esters and polyimides.

When the other polymer is contained in the liquid crystal alignment agent, the content of the other polymer can be appropriately set as long as the effect of the present invention is not impaired. Specifically, the content of the other polymer is more preferably 5% by mass or less, further preferably 3% by mass or less, and 1% by mass or less, based on the total amount of the polymer components contained in the liquid crystal alignment agent. Is even more preferable.

(solvent)
In the liquid crystal alignment agent of the present disclosure, the polymer [A], the polymer [B], the polymer [C] and other components used as necessary are preferably dispersed or dissolved in a suitable solvent. Is prepared as a liquid composition.

As the solvent, an organic solvent is preferably used. Specific examples thereof include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, phenol, and γ-. Butylolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, 1-hexanol, 2-hexanol, propane-1,2- Dire, 3-methoxy-1-butanol, ethylene glycol monomethyl ether, methyl lactate, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, ethyl propionate, methyl methoxypropione- Ethylene glycol methyl ether, ethylene 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. Glycolethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutylketone, isoamylpropionate, isoamylisobutyrate, diisopentyl ether, Ethylene carbonate, propylene carbonate, propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentanone, cyclohexanone and the like can be mentioned.

In addition to the above, examples of other components contained in the liquid crystal alignment agent include antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers and the like. The blending ratio of the other components can be appropriately selected according to each compound as long as the effects of the present disclosure are not impaired.

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. When the solid content concentration is 1% by mass or more, the film thickness of the coating film can be sufficiently secured, and a liquid crystal alignment film showing good liquid crystal alignment can be easily obtained. On the other hand, when the solid content concentration is 10% by mass or less, the coating film can be made to have an appropriate thickness, it is easy to obtain a liquid crystal alignment film showing good liquid crystal alignment, and the viscosity of the liquid crystal alignment agent is appropriate. There is a tendency that the coatability can be improved.

≪Liquid crystal alignment film and liquid crystal element≫
The liquid crystal alignment film of the present disclosure is produced 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 drive method of the liquid crystal in the liquid crystal element is not particularly limited, and for example, TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS type, FFS type, OCB (Optically Compensated Bend). It can be applied to various modes such as type and PSA type (Polymer Sustained Alignment). The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, the base material used differs depending on the desired operation mode. Step 2 and step 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 (lipid ring type olefin) can be used. As the transparent conductive film provided on one surface of the substrate, a NESA film made of tin oxide (SnO ₂ ) (registered trademark of PPG, USA) and indium oxide-tin oxide (In _{2O 3} -SnO ₂ ) are ITO. Examples include membranes. 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 a comb-shaped patterned electrode and a facing substrate not provided with an electrode are used.

The method of applying the liquid crystal alignment agent to the substrate is not particularly limited, and is, for example, a spin coating method, a printing method (for example, an offset printing method, a flexographic printing method, etc.), an inkjet method, a slit coating method, a bar coater method, and an extension. It can be performed by a die method, a direct gravure coater method, a chamber doctor coater method, an offset gravure coater method, an impregnation coater method, an MB coater method, or the like.

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 prebake temperature is preferably 30 to 200 ° C., and the prebake 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 280 ° C, more preferably 80 to 250 ° C. The post-bake time is preferably 5 to 200 minutes. The film thickness of the formed film is preferably 0.001 to 1 μm. As a result, a film containing the polymer [A'], the polymer [B], and the polymer [C] in which the protecting group is removed from the partial structure represented by the above formula (1) of the polymer [A]. Can be formed on the substrate. The polymer [A'] has a structural unit containing a -NH- group in a portion different from the group involved in the polymerization.

<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. As the alignment treatment, it is preferable to use a rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton or the like, or a photoalignment treatment in which the coating film is irradiated with light to impart a liquid crystal alignment ability. When manufacturing a vertically oriented liquid crystal element, the coating film formed in step 1 may be used as it is as a liquid crystal alignment film, and the coating film is subjected to an alignment treatment in order to further enhance the liquid crystal alignment ability. You may.

The light irradiation for photo-alignment includes a method of irradiating the coating film after the post-baking process, a method of irradiating the coating film after the pre-baking process and before the post-baking process, and a pre-baking process and a post-baking process. At least one of them can be used by a method of irradiating the coating film while heating the coating film, or the like. 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. In the case of unpolarized radiation, the irradiation direction is diagonal.

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

<Step 3: Construction of LCD cell>
A liquid crystal cell is manufactured by preparing two base materials on which a liquid crystal alignment film is formed as described above and arranging the liquid crystal between the two base materials arranged opposite to each other. In order to manufacture a liquid crystal cell, for example, two base materials are arranged facing each other through a gap so that the liquid crystal alignment films face each other, and the peripheral portions of the two base materials are bonded with a sealing agent to the surface of the substrate. Examples thereof include a method of injecting and filling a liquid crystal in a cell gap surrounded by a sealing agent and then sealing the injection hole, a method of using an ODF method, and the like. A bead spacer or a columnar spacer is arranged as an in-plane spacer between the two substrates, thereby forming a cell gap. As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used. The sealant can be applied onto the substrate by, for example, a screen printing method on the surface of the liquid crystal alignment film on at least one of the two substrates on which the liquid crystal alignment film is formed. ..

As the liquid crystal, either a positive type or a negative type may be used, but a negative type is preferable. Examples of the negative liquid crystal display include "MLC-6608", "MLC-6609", "MLC-6610", and "MLC-7026-100" manufactured by Merck. In particular, when a negative type liquid crystal is used in the IPS type and FFS type liquid crystal elements, it is preferable in that the transmission loss at the upper part of the electrode can be reduced and the contrast can be improved. Examples of the liquid crystal include a nematic liquid crystal and a smectic liquid crystal, and among them, the nematic liquid crystal is preferable.

When manufacturing a liquid crystal display device, a polarizing plate is subsequently attached to the outer surface of the liquid crystal cell to obtain a liquid crystal display element. Examples of the polarizing plate include a polarizing plate in which a polarizing film called "H film" in which polyvinyl alcohol is stretched and 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 element of the present invention can be effectively applied to various uses. Specifically, for example, various display devices such as watches, portable game machines, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, LCD TVs, information displays, etc. , Can be used as a dimmer, a retardation film and the like.

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

In the following examples, the weight average molecular weight (Mw) of the polymer, the imidization ratio of the polyimide in the polymer solution, and the solution viscosity of the polymer solution were measured by the following methods. The required amounts of the raw material compounds and polymers used in the following examples were secured by repeating the synthesis on the synthetic scale shown in the following synthesis examples as necessary.
[Weight average molecular weight (Mw) of polymer]
The weight average molecular weight (Mw) is a polystyrene-equivalent value measured by GPC under the following conditions.
Column: TSKgelGRCXLII manufactured by Tosoh Corporation
Solvent: N, N-dimethylformamide solution containing lithium bromide and phosphoric acid Temperature: 40 ° C
Pressure: 68kgf / cm ²
[Imidization rate of polyimide]
The polyimide solution was poured into pure water, the obtained precipitate was sufficiently dried under reduced pressure at room temperature, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance. From the obtained ¹ H-NMR spectrum, the imidization rate [%] was determined by the following mathematical formula (1).
Imidization rate [%] = (1- (β ¹ / (β ² × α))) × 100… (1)
(In formula (1), β ¹ is the peak area derived from the proton of the NH group appearing near the chemical shift of 10 ppm, β ² is the peak area derived from other protons, and α is the precursor of the polymer (polyamic acid). ) Is the ratio of the number of other protons to one proton of the NH group.)
[Solution viscosity of polymer solution]
The solution viscosity (mPa · s) of the polymer solution was measured at 25 ° C. using an E-type rotational viscometer.

The abbreviations of the compounds used in the examples are as follows.
(Tetracarboxylic acid derivative)
-Compound (AN-1) to Compound (AN-8): A compound represented by each of the following formulas (AN-1) to (AN-8).

(Diamine compound)
-Compound (DA-1) to compound (DA-12): Compound / compound (DA-19) to compound (DA-27) represented by each of the above formulas (DA-1) to (DA-12). , Compound (DA-42): Compound / compound (DA-32) to compound (DA-40) represented by each of the above formulas (DA-19) to (DA-27) and formula (DA-42). : Compounds / compounds (DA-13) to compounds (DA-18) represented by the above formulas (DA-32) to (DA-40), compounds (DA-28) to compounds (DA-31). , Compound (DA-41): Compounds represented by the following formulas (DA-13) to (DA-18), formulas (DA-28) to formulas (DA-31) and formulas (DA-41), respectively.

<Synthesis of polymer>
1. 1. Synthesis of polyamic acid [Synthesis example 1]
Compound (DA-1) is dissolved in N-methyl-2-pyrrolidone (NMP), 0.95 equivalent (molar ratio) of compound (AN-1) is added, and the reaction is carried out at 60 ° C. for 6 hours to carry out a polyamic acid. Was obtained in an amount of 15% by mass. A small amount of the obtained polyamic acid solution was taken, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by mass was 128 mPa · s. The polyamic acid solution was then poured into a large excess of methanol to precipitate the reaction product. The precipitate was washed with methanol and dried under reduced pressure at 40 ° C. for 15 hours to obtain a polyamic acid (referred to as "polymer (A-1)"). The weight average molecular weight (Mw) of the obtained polymer was 27,000.

[Synthesis Examples 2-8, 11-16, 18-53: Polymers (A-2) to (A-8), (A-11) to (A-16), (A-18), (A- 19), (B-1) to (B-20), (C-1) to (C-14) synthesis]
Polymers (A-2) to (A-) are the same as in Synthesis Example 1 except that the types and molar ratios of the tetracarboxylic dianhydride and the diamine compound are changed as shown in Tables 1 to 4 below, respectively. 8), (A-11) to (A-16), (A-18), (A-19), (B-1) to (B-20), (C-1) to (C-14). Was obtained respectively. For acid derivatives (tetracarboxylic acid dianhydride in the synthesis of polyamic acid), the values in Tables 1 to 4 indicate the ratio of each compound used to 100 mol parts of the total amount of acid derivatives used in the synthesis (mol). Part), and for the diamine compound, the ratio (molar part) of each compound to 100 mol parts of the total amount of the diamine compounds used for the synthesis is shown.

[Synthesis Example 17: Synthesis of Polymer (A-17)]
Compound (DA-13) is dissolved in N-methyl-2-pyrrolidone (NMP), 0.95 equivalent (molar ratio) of compound (AN-1) is added, and the reaction is carried out at 60 ° C. for 6 hours to carry out a polyamic acid. Was obtained in an amount of 15% by mass. To this polyamic acid solution, 0.05 equivalent (molar ratio) of di-tert-butyl dicarbonate was added, and the mixture was stirred for 15 hours under room temperature conditions. The polyamic acid solution was then poured into a large excess of methanol to precipitate the reaction product. The obtained precipitate was washed with methanol and dried at 40 ° C. under reduced pressure for 15 hours to obtain a polyamic acid having a Boc group introduced at the polymerization terminal (referred to as "polymer (A-17)"). Obtained. The weight average molecular weight (Mw) of the obtained polymer was 25,000.

2. 2. Polyimide synthesis [Synthesis example 9: Synthesis of polymer (A-9)]
Polymerization was carried out in the same manner as in Synthesis Example 1 except that the types and molar ratios of the tetracarboxylic dianhydride and the diamine compound were changed as shown in Table 1 below to obtain a solution containing 15% by mass of the polyamic acid. rice field. Next, NMP was added to the obtained polyamic acid solution to prepare a solution having a polyamic acid concentration of 10% by mass, pyridine and acetic anhydride were added, and a dehydration ring closure reaction was carried out at 60 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with a new NMP to obtain a solution containing 15% by mass of polyimide having an imidization rate of about 85%. The polyimide solution was then poured into a large excess of methanol to precipitate the reaction product. The precipitate was washed with methanol and dried under reduced pressure at 40 ° C. for 15 hours to obtain a polyimide (referred to as "polymer (A-9)"). The weight average molecular weight (Mw) of the obtained polymer was 33000.

3. 3. Synthesis of polyamic acid ester [Synthesis Example 10: Synthesis of polymer (A-10)]
70 mol parts of compound (DA-5), 15 mol parts of compound (DA-6) and 15 mol parts of compound (DA-3) as diamine compound, 2.5 equivalents (molar ratio) to the total amount of diamine compound as base. Pyridine and N-methyl-2-pyrrolidone (NMP) as a solvent were added and dissolved. While stirring this solution with water cooling, add 97 mol parts of dimethyl-1,3-bis (chlorocarbonyl) cyclobutane-2,4-carboxylate as an acid derivative, and NMP so that the solid content concentration becomes 5% by mass. Was added, and the mixture was stirred for 4 hours while cooling with water. This solution is poured into water to precipitate the polymer, and the polymer is collected by filtration through suction filtration, washed again with water, washed three times with methanol, and dried under reduced pressure at 40 ° C. to obtain a polyamic acid ester (polyamic acid ester). This is referred to as "polymer (A-10)"). The weight average molecular weight (Mw) of the polymer (A-10) was 29000.

[Example 1]
1. 1. Preparation of liquid crystal alignment agent 20 parts by mass of the polymer (A-1) obtained in Synthesis Example 1, 40 parts by mass of the polymer (B-7) obtained in Synthesis Example 26, and the polymer obtained in Synthesis Example 40. 40 parts by mass of (C-3) is diluted with NMP, γ-butyl lactone (GBL), ethylene glycol monobutyl ether (BC), diacetone alcohol (DAA), and diethylene glycol diethyl ether (DEDG) to obtain a solid content. A solution having a concentration of 4.0% by mass and a solvent composition ratio of NMP: GBL: BC: DAA: DEDG = 30:30: 20: 10: 10 (mass ratio) was obtained. A liquid crystal alignment agent (R-1) was prepared by filtering this solution with a filter having a pore size of 0.2 μm.

2. 2. Formation of liquid crystal alignment film by rubbing method A flat plate electrode (bottom electrode), an insulating layer and a comb-shaped electrode (top electrode) are laminated on one side in this order, and a glass substrate having a columnar spacer on the electrode forming surface and an electrode are provided. A facing glass substrate that was not used was prepared. On each surface of this pair of substrates, the above 1. The liquid crystal alignment agent (R-1) prepared in 1) was applied using a spinner, heated (pre-baked) on a hot plate at 80 ° C. for 1 minute, and then dried in a nitrogen-substituted 230 ° C. oven for 30 minutes (pre-baking). Post-baking) was performed to form a coating film having an average film thickness of 0.1 μm. A rubbing treatment was performed on the surface of the coating film using a rubbing machine having a roll wrapped with a nylon cloth at a roll rotation speed of 1000 rpm, a stage moving speed of 3 cm / sec, and a hair-foot pushing length of 0.3 mm. The coating film subjected to the rubbing alignment treatment was ultrasonically washed in ultrapure water for 1 minute and then dried in an oven at 100 ° C. for 10 minutes to form a liquid crystal alignment film.

3. 3. Manufacture of FFS type liquid crystal display element 2. Of the pair of substrates having a liquid crystal alignment film produced in 1 above, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is screened on the edge of the surface of one of the substrates on which the liquid crystal alignment film is formed, leaving a liquid crystal injection port. After the printing was applied, the substrates were overlapped and pressure-bonded so that the rubbing directions of the respective substrates were antiparallel, and the adhesive was thermally cured at 150 ° C. for 1 hour. Next, a negative type nematic liquid crystal (MLC-6608, manufactured by Merck Group) 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 remove the flow orientation at the time of liquid crystal injection, this was heated at 120 ° C. and then slowly cooled to room temperature. Next, a polarizing plate was attached to both outer surfaces of the substrate to manufacture an FFS type liquid crystal display element.

4. Evaluation of adhesion to sealant (seal adhesion) 2. In the same manner as above, a pair of substrates having a liquid crystal alignment film was prepared using the liquid crystal alignment agent (R-1). Next, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is applied to the central portion of each of the alignment film forming surfaces of the pair of substrates, and then the alignment film forming surfaces are overlapped and pressure-bonded so as to face each other. The adhesive was cured to form a sealant. A tensile tester was used to measure the pressure at which the sealant peeled off. The one that peeled off when a pressure of 2.0 kgf or more was applied was "excellent", the one that peeled off when a pressure of 1.0 kgf or more and less than 2.0 kgf was applied was "good", and the one that peeled off when a pressure of 1.0 kgf or more was applied was peeled off at a pressure of less than 1.0 kgf. What was done was regarded as "defective". As a result, it was evaluated as "excellent" in this example.

5. Evaluation of AC afterimage characteristics Except for the fact that polarizing plates were not attached to both outer sides of the substrate, the above 3. The same operation as in the above was performed to produce an FFS type liquid crystal cell. This FFS type liquid crystal cell is driven at an AC voltage of 10 V for 72 hours, and then using a device in which a splitter and an analyzer are arranged between a light source and a light amount detector, 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 amount of light transmitted under the cross Nicol. It is the minimum amount of light transmission with a liquid crystal cell sandwiched between them.)
The black level in the dark state is represented by the minimum relative transmittance of the liquid crystal cell, and in the FFS type liquid crystal cell, the smaller the black level in the dark state, the better the contrast. Those having a minimum relative transmittance of less than 0.3% were regarded as "excellent", those having a minimum relative transmittance of 0.3% or more and less than 2.0% were regarded as "good", and those having a minimum relative transmittance of 2.0% or more were regarded as "poor". As a result, it was evaluated as "excellent" in this example.

6. Evaluation of DC afterimage characteristics 3. For the liquid crystal display element manufactured in, after driving with AC2.5V and setting the luminance difference between any two pixels to 0, DC1V is applied to only one pixel for 20 minutes while driving with AC2.5V. Accumulated charge. When the application of DC1V was terminated and the drive was returned only to AC2.5V, the accumulated charge caused a difference in luminance between the two pixels. By observing the change over time in this luminance difference, the relaxation time in the process of decaying the residual DC value was calculated. When the relaxation time was less than 10 seconds, it was judged as "excellent", when the relaxation time was 10 seconds or more and less than 20 seconds, it was judged as "good", and when the relaxation time was 20 seconds or more, it was judged as "poor". .. As a result, it was evaluated as "excellent" in this example.

7. Evaluation of adhesion to the substrate (spacer adhesion) 3. We observed orientation defects after applying external stress to the liquid crystal display element manufactured in. Specifically, after pressing a rod-shaped indenter having a diameter of 5 mm at a weight of 2.0 kgf and a rotation speed of 200 rpm for 10 minutes, the number of alignment defect points in the pixel where light leakage occurred under the cross Nicol was counted. .. When the liquid crystal alignment film has high toughness, when the liquid crystal display element is pressed from above in the thickness direction, the liquid crystal alignment film deforms following the movement of the spacer in the thickness direction and returns to its original state. Hard to peel off from the base material. In this case, it can be said that the adhesion of the liquid crystal alignment film to the substrate is good. On the other hand, if the toughness of the liquid crystal alignment film is not sufficient, the liquid crystal alignment film cannot follow the movement of the spacer when the liquid crystal display element is pressed from above in the thickness direction, and the pressure causes cracks in the liquid crystal alignment film. It is easy to peel off from the base material. In this case, it can be said that the adhesion of the liquid crystal alignment film to the substrate is poor. Therefore, in this embodiment, the adhesion of the liquid crystal alignment film to the substrate (particularly, the adhesion at the spacer portion) was evaluated by observing the alignment defect after applying external stress to the liquid crystal display element. The evaluation criteria were "excellent" when the location of the alignment defect was 0 points, "good" when the location of the alignment defect was 1 point or more and less than 5 points, and the location of the alignment defect was 5 points or more. Was regarded as "defective". As a result, it was evaluated as "excellent" in this example.

8. Evaluation of inkjet coatability As a substrate to which the liquid crystal alignment agent (R-1) is applied, a glass substrate with a transparent electrode made of ITO is heated on a hot plate at 200 ° C. for 1 minute, and then UV / ozone cleaning is performed to perform a transparent electrode. The one immediately after setting the contact angle of water on the surface to 10 ° or less was used. The liquid crystal alignment agent (R-1) prepared above was applied onto the transparent electrode surface of the glass substrate with a transparent electrode using an inkjet coating machine (manufactured by Shibaura Mechatronics Co., Ltd.). The coating conditions at this time were 2,500 times / (nozzle / minute) and 2 reciprocations (4 times in total) with a discharge rate of 250 mg / 10 seconds. After coating, the mixture was allowed to stand for 1 minute and then heated at 80 ° C. to form a coating film having an average film thickness of 0.1 μm. With respect to the obtained coating film, the number of unevenness and repellent was observed with the naked eye under the irradiation of the interference fringe measurement lamp (sodium lamp). When the total number of unevenness and repellent parts is 0, it is regarded as "excellent", when the total number of unevenness and repellent parts is 1 or more and less than 3, it is "good", and when the total number of unevenness and repellent parts is 3 or more, it is "excellent". It was judged as "bad". As a result, the inkjet coating property of the liquid crystal alignment agent of this example was evaluated as "excellent".

[Examples 2-9, 11-19 and Comparative Examples 1-9]
A liquid crystal alignment agent was prepared in the same manner as in Example 1 except that the composition of the liquid crystal alignment agent was changed as shown in Table 5 below. Further, using the obtained liquid crystal alignment agent, a liquid crystal display element was manufactured in the same manner as in Example 1, and various evaluations were performed. The results are shown in Table 5 below. In Table 5, the numerical values in parentheses of each polymer represent the mixing ratio (parts by mass) of each polymer in solid content with respect to 100 parts by mass of the total amount of the polymer components used for preparing the liquid crystal alignment agent.

[Example 10]
The liquid crystal alignment agent was prepared in the same manner as in Example 1 except that the composition of the liquid crystal alignment agent was changed as shown in Table 5 below and the photoalignment method was used instead of the rubbing method for the liquid crystal alignment film. A liquid crystal display element and a liquid crystal cell were manufactured and various evaluations were performed. The liquid crystal alignment film was formed by the photo-alignment method according to the following procedure.
(Formation of liquid crystal alignment film by photo-alignment method)
A flat plate electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) are laminated on one side in this order, and a glass substrate having a columnar spacer on the electrode forming surface and a facing glass substrate having no electrode are provided. A liquid crystal alignment agent was applied onto each surface with a spinner, and heated (pre-baked) on a hot plate at 80 ° C. for 1 minute. Then, the inside of the refrigerator was dried (post-baked) for 30 minutes in a nitrogen-substituted oven at 230 ° C. to form a coating film having an average film thickness of 0.1 μm. The obtained coating film was subjected to photoalignment treatment by irradiating the obtained coating film with ultraviolet rays of 1,000 J / m ² including a linearly polarized 254 nm emission line from the normal direction of the substrate using an Hg-Xe lamp. It should be noted that this irradiation amount is a value measured using a photometer measured based on a wavelength of 254 nm. Next, the coating film subjected to the photo-alignment treatment was heated in a clean oven at 230 ° C. for 30 minutes to perform a heat treatment to form a liquid crystal alignment film.
Further, by carrying out the above series of operations by changing the ultraviolet irradiation amount after post-baking in the range of 100 to 10,000 J / m ² , three or more liquid crystal cells having different ultraviolet irradiation amounts can be manufactured. Then, various evaluations were carried out in the same manner as in Example 1 using a liquid crystal cell having an exposure amount (optimum exposure amount) showing the best orientation characteristics.

As shown in Table 5, in Examples 1 to 19, various characteristics such as seal adhesion, AC afterimage characteristics, DC afterimage characteristics, spacer adhesion and coatability are improved in a well-balanced manner as compared with Comparative Examples 1 to 9. rice field. On the other hand, Comparative Examples 1 to 9 containing no one of the polymer [A], the polymer [B] and the polymer [C] have either seal adhesion, DC afterimage characteristics or spacer adhesion. It was evaluated as "bad".

Claims (10)

A polymer [A] having a partial structure represented by the following formula (1) and not having a partial structure represented by the following formula (2).
A polymer [B] having a partial structure represented by the following formula (2) and
A polymer [C] having the following partial structure X in the main chain and not having the partial structure represented by the following formula (1) and the partial structure represented by the following formula (2).
A liquid crystal alignment agent containing.
Partial structure X: In the structure represented by-(CH ₂ ) _a- (where a is an integer of 2 to 20) or- (CH ₂ ) _a- , any methylene group is-. Selected from the group consisting of NR ^7- , -O-, -COO-, -NR ⁷ -CO-, -NR ⁷ -COO-, -NR ⁸ -CO-NR ^9- and nitrogen-containing non-aromatic heterocyclic groups. A structure that is replaced by at least one group (where R ⁷ is a hydrogen atom or an alkyl group; R ⁸ and R ⁹ are independently hydrogen atoms or alkyl groups, respectively, or with R ⁸ ). Represents a ring structure in which R ⁹ is combined with each other and is composed of a nitrogen atom to which R ⁸ is bonded, a nitrogen atom to which R ⁹ is bonded, and -CO-. In the partial structure X, -NR ^7- , -O-, -COO-, -NR ⁷ -CO-, -NR ⁷ -COO-, -NR ⁸ -CO-NR ^9- and nitrogen-containing non-aromatic heterocyclic groups are not adjacent to each other)

(In equation (1), R ¹ is a protecting group. "*" Indicates a bond.)

(In the formula (2), A ¹ and A ⁴ are independently divalent aromatic ring groups, respectively. R ² and R ³ are independently hydrogen atoms or monovalent organic groups, respectively. B ¹ is. , Single bond, -NR ^4- , -O- or a divalent aromatic heterocyclic group. R ⁴ is a hydrogen atom or a monovalent organic group. If B ¹ is a single bond, A ² Is a divalent aromatic ring group and A ³ is a single-bonded or divalent aromatic ring group. When B ¹ is a divalent aromatic heterocyclic group, A ² and A ³ are independent of each other. It is a single-bonded or divalent aromatic ring group. When B ¹ is -NR ^4- or -O-, A ² and A ³ are independently divalent aromatic ring groups, or A. The aromatic ring of ² and the aromatic ring of A3 ^are connected by a single bond or a chain structure to represent a nitrogen or oxygen-containing fused ring structure composed of -NR ^4- or -O-. Indicates that it is a bond.) The liquid crystal display according to claim 1, wherein the polymer [A], the polymer [B], and the polymer [C] are at least one selected from the group consisting of a polyamic acid, a polyamic acid ester, and a polyimide. Aligning agent. The liquid crystal alignment agent according to claim 1 or 2, wherein the polymer [C] contains a structural unit derived from a diamine represented by the following formula (3-1).

(In the formula (3-1), A ⁵ is a divalent aromatic ring group. A ⁶ is a single bond or a divalent aromatic ring group. Y ² is a divalent having the partial structure X. ^R5 is a hydrogen atom or a monovalent organic group.) The partial structure X has at least one group selected from the group consisting of -COO-, -NR ⁷ -CO-, -NR ⁷ -COO- and -NR ⁸ -CO-NR ^9- . The liquid crystal alignment agent according to any one of 1 to 3. The liquid crystal alignment agent according to any one of claims 1 to 4, wherein the polymer [A] contains a structural unit derived from a diamine represented by the following formula (1-1).

(In the formula (1-1), A ⁷ and A ⁸ are independently divalent aromatic ring groups. Y ¹ is a divalent organic group. R is 0 or 1, but r. When 1, at least one of A ⁷ , A ⁸ and Y ¹ has a partial structure represented by the above formula (1). When r is 0, A ⁷ has the above formula (1). It has a partial structure represented.) The liquid crystal alignment agent according to any one of claims 1 to 5, wherein the polymer [A] has the following partial structure Y in the main chain.
Partial structure Y: In the structure represented by-(CH ₂ ) _b- (where b is an integer of 2 to 20) or- (CH ₂ ) _b- , any methylene group is-. Selected from the group consisting of NR ^10- , -O-, -COO-, -NR ¹⁰ -CO-, -NR ¹⁰ -COO-, -NR ¹⁰ -CO-NR ^11- and nitrogen-containing non-aromatic heterocyclic groups. A structure that is replaced by at least one group (where R ¹⁰ and R ¹¹ are independently hydrogen atoms or monovalent organic groups. In the partial structure Y, -NR ^10- , -O-, -COO-, -NR ¹⁰ -CO-, -NR ¹⁰ -COO-, -NR ¹⁰ -CO-NR ^11- and nitrogen-containing non-aromatic heterocyclic groups are not adjacent to each other) The liquid crystal alignment agent according to any one of claims 1 to 6, wherein the polymer [B] contains a structural unit derived from a diamine represented by the following formula (2-1).

(In the formula (2-1), A ¹ to A ⁴ , B ¹ , R ² and R ³ are synonymous with the above formula (2), respectively.) A liquid crystal alignment film formed by the liquid crystal alignment agent according to any one of claims 1 to 7. A polymer having a structural unit containing a partial structure represented by the following formula (1A) in a portion different from the group involved in the polymerization and not having a partial structure represented by the following formula (2), and a polymer.
A polymer having a partial structure represented by the following formula (2) and
A polymer having the following partial structure X in the main chain and not having the partial structure represented by the following formula (2),
A liquid crystal alignment film containing.
Partial structure X: In the structure represented by-(CH ₂ ) _a- (where a is an integer of 2 to 20) or- (CH ₂ ) _a- , any methylene group is-. Selected from the group consisting of NR ^7- , -O-, -COO-, -NR ⁷ -CO-, -NR ⁷ -COO-, -NR ⁸ -CO-NR ^9- and nitrogen-containing non-aromatic heterocyclic groups. A structure that is replaced by at least one group (where R ⁷ is a hydrogen atom or an alkyl group; R ⁸ and R ⁹ are independently hydrogen atoms or alkyl groups, respectively, or with R ⁸ ). Represents a ring structure in which R ⁹ is combined with each other and is composed of a nitrogen atom to which R ⁸ is bonded, a nitrogen atom to which R ⁹ is bonded, and -CO-. In the partial structure X, -NR ^7- , -O-, -COO-, -NR ⁷ -CO-, -NR ⁷ -COO-, -NR ⁸ -CO-NR ^9- and nitrogen-containing non-aromatic heterocyclic groups are not adjacent to each other)

(In equation (1A), "*" indicates a bond.)

(In the formula (2), A ¹ and A ⁴ are independently divalent aromatic ring groups, respectively. R ² and R ³ are independently hydrogen atoms or monovalent organic groups, respectively. B ¹ is. , Single bond, -NR ^4- , -O- or a divalent aromatic heterocyclic group. R ⁴ is a hydrogen atom or a monovalent organic group. If B ¹ is a single bond, A ² Is a divalent aromatic ring group and A ³ is a single-bonded or divalent aromatic ring group. When B ¹ is a divalent aromatic heterocyclic group, A ² and A ³ are independent of each other. It is a single-bonded or divalent aromatic ring group. When B ¹ is -NR ^4- or -O-, A ² and A ³ are independently divalent aromatic ring groups, or A. The aromatic ring of ² and the aromatic ring of A3 ^are linked by a single bond or a chain structure to represent a nitrogen or oxygen-containing fused ring structure composed of -NR ^4- or -O-. Indicates that it is a bond.) A liquid crystal element comprising the liquid crystal alignment film according to claim 8 or 9.