TW202130794A - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

A liquid crystal aligning agent which contains the components (A) and (B) described below. (A): A polyimide which is obtained by imidizing a polyimide precursor that is obtained by a reaction between a tetracarboxylic acid component and a diamine component containing at least one diamine selected from among compounds of formula (1) and formula (2). In the formulae, A1 represents a single bond, a methylene group, an ether bond, an ester bond, an amide bond, a cyclohexylene group or an alkylene group having from 2 to 20 carbon atoms; an arbitrary -CH2 moiety of the alkylene group may be substituted by an ether group, an ester group, an amide group, a cyclohexylene group, a phenylene group, a urea group, an amino group or a carbamate group; an arbitrary hydrogen atom in the amide group, the urea group and the amino group may be substituted by a methyl group or a tert-butoxycarbonyl group; A2 represents a fluorine atom or an alkyl group or alkoxy group having from 1 to 5 carbon atoms; an arbitrary hydrogen atom in the alkyl group or the alkoxy group may be substituted by a fluorine atom, while an arbitrary carbon atom therein may be substituted by an amino group that is protected by a tert-butoxycarbonyl group; each of the plurality of a's independently represents an integer from 0 to 4; if a plurality of A2 moieties are present, the A2 moieties may be the same as or different from each other; each of b and c independently represents an integer from 0 to 2; and if b is 0, c is 1 or 2 and A1 is an alkylene group. (B): An organic solvent which contains butyl cellosolve and butyl cellosolve acetate.

Description

Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element

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

The liquid crystal alignment film widely uses the so-called polyimide-based liquid crystal alignment film, which is coated with polyimide precursors such as polyimide (also known as polyimide) or soluble polyimide The liquid crystal alignment agent as the main component of the solution is fired.

In recent years, with the increase in screen size and high definition of liquid crystal display elements, the substrate used or the unevenness of the substrate level has also become larger. In this situation, for a large substrate, if there is a large unevenness, a uniform liquid crystal alignment film will be required.

In the production step of the liquid crystal alignment film, when the liquid crystal alignment agent containing polyamide acid or solvent-soluble polyimide (also called resin) is applied to the substrate, the industry generally uses flexographic printing method or Inkjet coating method and the like are performed. At this time, if the film-forming properties of the liquid crystal alignment agent are poor, repulsion or fine pores will occur, and this part will become a display defect when it is made into a liquid crystal display element. In contrast, among the solvents of the liquid crystal alignment agent, in addition to solvents with excellent resin solubility (also referred to as good solvents) N-methyl-2-pyrrolidone or γ-butyrolactone, etc., in order to improve the liquid crystal alignment agent For film forming properties, a solvent with low resin solubility (also referred to as a poor solvent), ethylene glycol monobutyl ether, etc. is also mixed (see, for example, Patent Document 1).

However, the poor solvent has a poor ability to dissolve polyamide acid or solvent-soluble polyimide, and therefore, if a large amount is mixed, there is a problem of resin precipitation. In addition, in the liquid crystal display elements for portable use such as smartphones and mobile phones that have been frequently used in recent years, in order to ensure as many display screens as possible, the sealant used for directing the substrate of the liquid crystal display element will be present in the adjacent liquid crystal display element. Position of the end of the alignment film. Therefore, when the film formability of the end of the liquid crystal alignment film is reduced, that is, when the end of the liquid crystal alignment film is not straight, or when the end is raised, the bonding effect between the liquid crystal alignment film and the sealant becomes low. There is a problem of lowering the display characteristics or reliability of the liquid crystal display element.

On the other hand, the inkjet method is attracting attention as a method for forming a liquid crystal alignment film that does not use a flexographic printing plate. The inkjet method is a method in which fine liquid droplets are dropped on a substrate, and a film is formed by wetting and spreading of the liquid. Not only does it not use a printing plate, but the printing pattern can be set freely, so the manufacturing steps of the liquid crystal display element can be simplified. In addition, there is no need to form a film on a dummy substrate, which is necessary for flexographic printing, and there is an advantage of less waste of coating liquid. With the inkjet method, it is expected that the cost of the liquid crystal panel will be reduced and the production efficiency will be improved.

However, although the inkjet method has the advantages of reducing the cost of the liquid crystal panel and improving the production efficiency, the liquid crystal alignment film formed by the inkjet method generally has the uniformity of the film thickness in the coating surface and the coating periphery The film forming precision of the part is in the relationship of mutual compensation. That is, generally, a material with high in-plane uniformity has a problem that the dimensional stability of the coating peripheral portion is low, and the film overflows from the set size.

Therefore, in order to form a polyimide film, as a composition having excellent film-forming properties, a document proposes a composition containing a specific poor solvent such as dipropylene glycol dimethyl ether (refer to Patent Document 2).

In addition, Patent Document 3 describes that a liquid crystal alignment film containing a solvent-soluble polyimide containing a specific diamine can obtain very high reliability even in negative liquid crystals that are very afraid of contaminants. Document 4 discloses that by using a liquid crystal alignment agent containing a solvent-soluble polyimide containing a specific diamine and a high imidization rate, it is possible to obtain a low pretilt angle of less than 1 degree or an excellent voltage retention, liquid crystal alignment The essence of the sexual liquid crystal alignment film. [Prior Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2-37324 Patent Document 2: Japanese Patent Application Publication No. 2018-83943 Patent Document 3: WO2015/199149 Patent Document 4: WO2019/082975

[The problem to be solved by the invention]

In the composition disclosed in Patent Document 1, in addition to N-methyl-2-pyrrolidone and γ-butyrolactone, a poor solvent, ethylene glycol monobutyl ether, is added in order to improve the film-forming properties of the liquid crystal alignment agent. When the composition is used in the inkjet method, in order to prevent nozzle clogging and long-term standby ejection of the periodic ejection liquid, the liquid formed from the polyimide solution will adhere to the surface of the inkjet head, especially if it contains high imidization In the case of polyimide at a higher rate, there will be problems that are prone to occur.

In view of this situation, the present invention aims to provide a liquid crystal alignment agent, which has excellent binding properties between liquids, good film-forming properties, and can be used stably for a long time even in an inkjet method, and a liquid crystal produced by the liquid crystal alignment agent. Alignment film and liquid crystal display element. [Means used to solve the problem]

The inventors have conducted intensive research and found that, for example, by using N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL) and ethylene glycol monobutyl ether (butyl cellosolve; BCS) The introduction of butyl cellosolve acetate, which is a poor solvent, has good film-forming properties and good dimensional stability of the coating peripheral portion. It can be used stably for a long period of time even in the inkjet method, and the present invention has been completed. In addition, it has been found that, especially in the case of dissolving a predetermined polyimide, the characteristics of such a solvent are effective, and the present invention has been completed.

式中，A₁ 為單鍵、亞甲基、醚鍵、酯鍵、醯胺鍵、伸環己基或碳數2~20之伸烷基。但是，該伸烷基之任意的－CH₂ －可被醚基、酯基、醯胺基、伸環己基、伸苯基、脲基、胺基或胺甲酸酯基取代，該醯胺基、該脲基、該胺基之任意的氫原子可被甲基或第三丁氧基羰基取代。A₂ 為氟原子或碳數1~5之烷基或烷氧基，該烷基或該烷氧基之任意的氫原子可被氟原子取代，任意的碳原子可被以第三丁氧基羰基保護的胺基取代。複數的a各自獨立，0~4之整數，在存在複數的A₂ 的情況下A₂ 可相同相異。b及c各自獨立，0~2之整數，在b為0的情況下c為1或2且A₁ 為伸烷基。 (B)：含有丁基溶纖劑及丁基溶纖劑醋酸酯之有機溶劑。 [發明之效果]The liquid crystal alignment agent of the present invention that achieves the above-mentioned objects contains the following (A) and (B). (A): A polyimide precursor that is a reactant of a diamine component containing at least one diamine selected from the following formula [1] and formula [2] and a tetracarboxylic acid component is imidized The obtained polyimide,

In the formula, A ₁ is a single bond, a methylene group, an ether bond, an ester bond, an amide bond, a cyclohexylene group or an alkylene group with 2 to 20 carbon atoms. However, any -CH ₂ -of the alkylene group may be substituted by an ether group, an ester group, an amide group, a cyclohexylene group, a phenylene group, a ureido group, an amine group or a urethane group. Any hydrogen atom of the ureido group and the amino group may be substituted by a methyl group or a tertiary butoxycarbonyl group. A ₂ is a fluorine atom or an alkyl group or alkoxy group with 1 to 5 carbon atoms. Any hydrogen atom of the alkyl group or the alkoxy group may be substituted by a fluorine atom, and any carbon atom may be substituted by a third butoxy group. A carbonyl protected amino group is substituted. The plural a are independent, an integer from 0 to 4, and A ₂ can be the same and different _{when there is a plural A 2.} b and c are each independent, an integer of 0 to 2, and when b is 0, c is 1 or 2 and A ₁ is an alkylene group. (B): Organic solvent containing butyl cellosolve and butyl cellosolve acetate. [Effects of Invention]

According to the present invention, it is possible to provide a liquid crystal alignment agent that has good film forming properties and good dimensional stability of the coating peripheral portion, and can be used stably for a long time even in the inkjet method, and a liquid crystal alignment film and liquid crystal display manufactured therefrom element.

The present invention will be described in further detail below. The liquid crystal alignment agent of the present invention contains the following (A) and (B). (A): A polyimide precursor that is a reactant of a diamine component containing at least one diamine selected from the above formula [1] and formula [2] and a tetracarboxylic acid component is imidized The polyimide. (B): Organic solvent containing butyl cellosolve and butyl cellosolve acetate.

The diamine used in the present invention contains at least one selected from the above-mentioned formula [1] or [2]. In the above formula [1], A ₂ is preferably a methyl group. a is preferably an integer from 0 to 1. In the above formula [2], from the viewpoint of improving the orientation of the liquid crystal, A _{1 has} a single bond, a methylene group, an ether bond, an ester bond, and an alkylene group having 2 to 10 carbon atoms (however, the alkylene group It is preferred that at least one of the groups -CH ₂ -is substituted by an ether group or an ester group). In the above formula [2], A ₂ is preferably a methyl group. a is preferably an integer from 0 to 1. b is preferably 1. c is preferably an integer of 1~2. More suitable specific structures of the diamine represented by the above formula [1] and the diamine represented by the formula [2] include the following formulas [d1-1]~[d1-2] or [d2-1]~[ Any structure of d2-28].

(式[d1-1]中，R為氟原子或碳數1~5之烷基或烷氧基，該烷基或該烷氧基之任意的氫原子可被氟原子取代，式[d1-2]中，Boc表示第三丁氧基羰基)

(In the formula [d1-1], R is a fluorine atom or an alkyl group or alkoxy group having 1 to 5 carbon atoms, and any hydrogen atom of the alkyl group or the alkoxy group may be substituted with a fluorine atom, and the formula [d1- 2], Boc represents the third butoxycarbonyl group)

(式[d2-8]中，R、R'各自獨立地為氟原子或者碳數1~5之烷基或烷氧基，該烷基或該烷氧基之任意的氫原子可被氟原子取代)

(In formula [d2-8], R and R'are each independently a fluorine atom or an alkyl group or alkoxy group having 1 to 5 carbon atoms, and any hydrogen atom of the alkyl group or the alkoxy group may be replaced by a fluorine atom replace)

(式中，Boc表示第三丁氧基羰基，在式[d2-17]之中存在複數的m時，複數的m可相同或相異)

(In the formula, Boc represents the tertiary butoxycarbonyl group. When there is a plural m in the formula [d2-17], the plural m may be the same or different)

More suitable specific structures of the diamine represented by the above formula [1] and the diamine represented by the formula [2] include the following structures.

The content of the diamine represented by the above formula [1] and the above formula [2] is preferably 50 mol% or more, preferably 70 mol% or more, relative to 1 mol of the total diamine component.

In the present invention, the diamine constituting the polyimide of (A) may include the diamines described below in addition to the diamines selected from the above-mentioned formulas [1] and [2].

Two or more types of diamines selected from the above-mentioned formulas [1] and [2] can be used, or three or more types can be used. In particular, it is preferable to use two or more or three or more diamines selected from the above formula [2].

＜Diamine with specific side chain structure＞ The diamine having a specific side chain structure exhibits vertical alignment and has at least one side chain structure selected from the group represented by the following formulas [S1] to [S3]. Hereinafter, regarding the example of the second diamine having the specific side chain structure, the diamine having the specific side chain structure represented by the formulas [S1] to [S3] will be sequentially described.

上述式[S1]中，X¹ 及X² 各自獨立地表示單鍵、    －(CH₂ )_a －(a表示1~15之整數)、－CONH－、－NHCO－、－CON(CH₃ )－、－NH－、－O－、－COO－、－OCO－或－((CH₂ )_a1 －A₁ )_m1 －。其中，a1表示1~15之整數，A₁ 表示氧原子或－COO－，m1表示1~2之整數。在m1為2的情況，複數的a1及A₁ 各自獨立地具有上述定義。[a]: Diamine having a specific side chain structure represented by the following formula [S1]

In the above formula [S1], X ¹ and X ² each independently represent a single bond, -(CH ₂ ) _a- (a represents an integer from 1 to 15), -CONH-, -NHCO-, -CON(CH ₃ ) －, －NH－, －O－, －COO－, －OCO－ or －((CH ₂ ) _a1 －A ₁ ) _m1 －. Among them, a1 represents an integer from 1 to 15, A ₁ represents an oxygen atom or -COO-, and m1 represents an integer from 1 to 2. In m1 is 2, a plurality of A ₁ and a1 are each independently defined above.

In particular, from the viewpoint of the availability of raw materials or the ease of synthesis, X ¹ and X ² each independently have a single bond, -(CH ₂ ) _a- (a represents an integer from 1 to 15), -O-, -CH ₂ O- or -COO- is preferable, and a single bond, -(CH ₂ ) _a- (a represents an integer of 1 to 10), -O-, -CH ₂ O- or -COO- is preferable.

In addition, in the above formula [S1], G ¹ and G ² are each independently selected from the group consisting of a divalent aromatic group with 6 to 12 carbons and a divalent alicyclic group with 3 to 8 carbons The bivalent cyclic group. Any hydrogen atom on the cyclic group can be replaced by an alkyl group with 1 to 3 carbons, an alkoxy group with 1 to 3 carbons, a fluorine-containing alkyl group with 1 to 3 carbons, and a fluorine-containing alkyl group with 1 to 3 carbons. Fluorine-containing alkoxy or fluorine atom substitution. m and n each independently represent an integer from 0 to 3, and the total of m and n is 1 to 6, preferably 1 to 4.

In addition, in the above formula [S1], R ¹ represents an alkyl group with 1 to 20 carbons, an alkoxy group with 1 to 20 carbons, or an alkoxyalkyl group with 2 to 20 carbons. Any hydrogen atom forming R ¹ may be substituted by a fluorine atom. Among them, examples of the divalent aromatic group having 6 to 12 carbon atoms include a phenylene group, a biphenyl structure, and a naphthylene group. In addition, examples of the divalent alicyclic group having 3 to 8 carbon atoms include cyclopropylidene, cyclohexylene, and the like.

Therefore, suitable specific examples of the above formula [S1] include the following formulas [S1-x1] to [S1-x7].

In the above formulas [S1-x1] to [S1-x7], R ¹ is the same as in the case of the above formula [S1]. X ^p represents-(CH ₂ ) _a- (a represents an integer from 1 to 15), -CONH-, -NHCO-, -CON(CH ₃ )-, -NH-, -O-, _{-CH 2 O-,} -CH ₂ OCO-, -COO- or -OCO-. A ₁ represents an oxygen atom or -COO-* (the bonding bond with "*" is bonding with (CH ₂ ) _a2 ). A ₂ represents an oxygen atom or *-COO- (the bonding bond with "*" is bonding with (CH ₂ ) _a2 ). a3 represents an integer of 0 or 1, and a1 and a2 each independently represent an integer of 2-10. Cy represents 1,4-cyclohexylene or 1,4-phenylene.

上述式[S2]中，X³ 表示單鍵、－CONH－、－NHCO－、－CON(CH₃ )－、－NH－、－O－、－CH₂ O－、－COO－或－OCO－。尤其，從液晶配向劑的液晶配向性的觀點看來，X³ 以－CONH－、－NHCO－、－O－、－CH₂ O－、－COO－或－OCO－為佳。[b]: Diamine having a specific side chain structure represented by the following formula [S2]

In the above formula [S2], X ³ represents a single bond, -CONH-, -NHCO-, -CON(CH ₃ )-, -NH-, -O-, -CH ₂ O-, -COO- or -OCO- . In particular, from the viewpoint of the liquid crystal alignment of the liquid crystal alignment agent, X ^{3 is} preferably -CONH-, -NHCO-, -O-, -CH ₂ O-, -COO- or -OCO-.

In addition, in the above formula [S2], R ² represents an alkyl group having 1 to 20 carbons or an alkoxyalkyl group having 2 to 20 carbons. Any hydrogen atom forming R ² may be substituted by a fluorine atom. In particular, from the viewpoint of the liquid crystal alignment of the liquid crystal alignment agent, R ² is preferably an alkyl group having 3 to 20 carbons or an alkoxyalkyl group having 2 to 20 carbons. A suitable specific example of the formula [S2], X ³ is any one of -O-, -CH ₂ O-, -COO- or -OCO-, and R ² is an alkyl group with 3 to 20 carbons or 2 The alkoxyalkyl group of ~20 is preferable, and the case where R ² is an alkyl group of 3 to 20 carbon atoms is more preferable. ^{Any hydrogen atom forming R 2} may be substituted by a fluorine atom.

上述式[S3]中，X⁴ 表示－CONH－、－NHCO－、－O－、－CH₂ O－、－COO－或－OCO－。R³ 表示具有類固醇骨架的構造。此處的類固醇骨架具有三個六員環及一個五員環鍵結成之下述式(st)所表示的骨架。此外，該類固醇骨架所具有的環可具有雙鍵。

[c]: Diamine having a specific side chain structure represented by the following formula [S3]

In the above formula [S3], X ⁴ represents -CONH-, -NHCO-, -O-, -CH ₂ O-, -COO- or -OCO-. R ³ represents a structure having a steroid skeleton. The steroid skeleton here has a skeleton represented by the following formula (st) bonded by three six-membered rings and one five-membered ring. In addition, the ring possessed by the steroid skeleton may have a double bond.

Examples of the above formula [S3] include the following formula [S3-x]. Me represents methyl.

In the above formula [S3-x], X represents the above formula [X1], [X2] or [X3]. In addition, Col represents any of the aforementioned formulas [Col1] to [Col3], and G represents any of the aforementioned formulas [G1] to [G4]. * Indicates a bonding key.

Examples of suitable combinations of X1, Col, and G in the above formula [S3-x] include the following combinations. That is, [X1] and [Col1] and [G1], [X1] and [Col1] and [G2], [X1] and [Col2] and [G1], [X1] and [Col2] and [G2] , [X1] and [Col3] and [G2], [X1] and [Col3] and [G1], [X2] and [Col1] and [G2], [X2] and [Col2] and [G2], [ X2] and [Col2] and [G1], [X2] and [Col3] and [G2], [X2] and [Col1] and [G1], [X3] and [Col2] and [G1], [X3] And [Col2] and [G2], [X3] and [Col2] and [G3].

In addition, specific examples of the above formula [S3] include the structure described in the paragraph [0024] of JP-A-4281427, which removes the hydroxyl group (Hydroxy) from a steroid compound, and the description in the paragraph [0030] of the same publication. The structure of removing the acid chloride group from the steroid compound, the structure of removing the amine group from the steroid compound described in the paragraph [0038] of the same publication, the structure of removing the halogen atom from the steroid compound in the paragraph [0042] of the same publication, and the Japanese Patent Application Publication 8-146421 paragraph [0018] ~ [0022] described structure and so on.

In addition, a representative example of the steroid skeleton includes cholesterol (a combination of [Col1] and [G2] in the above formula [S3-x]), but a steroid skeleton that does not contain this cholesterol can also be used. That is, the diamine having a steroid skeleton includes, for example, 3,5-diaminobenzoic acid cholesteryl ester, etc. However, it may be a diamine component that does not contain the diamine having such a cholesterol skeleton. In addition, for diamines with a specific side chain structure, diamines that do not contain amide bonds at the connection position between the diamine and the side chain can be used. In this embodiment, even if a diamine component that does not contain a diamine having a cholesterol skeleton is used, it is possible to provide a liquid crystal alignment agent that can obtain a liquid crystal alignment film or a liquid crystal display element that can ensure a high voltage retention under long-term use.

In addition, the diamines having the side chain structure represented by the above formulas [S1] to [S3] are represented by the structures of the following formulas [1-S1] to [1-S3], respectively.

上述式[1-S1]中，X¹ 、X² 、G¹ 、G² 、R¹ 、m及n與上述式[S1]的情況同樣。上述式[1-S2]中，X³ 及R² 與上述式[S2]的情況同樣。上述式[1-S3]中，X⁴ 及R³ 與上述式[S3]的情況同樣。

In the above formula [1-S1], X ¹ , X ² , G ¹ , G ² , R ¹ , m, and n are the same as in the above formula [S1]. In the above formula [1-S2], X ³ and R ^{2 are the} same as in the above formula [S2]. In the above formula [1-S3], X ⁴ and R ^{3 are the} same as in the above formula [S3].

(Diamine with a specific side chain structure of a two-side chain type that exhibits vertical alignment) A diamine having a two-side chain type specific side chain structure exhibiting vertical alignment is represented by the following formula [N1], for example.

In the above formula [N1], X represents a single bond, -O-, -C(CH ₃ ) ₂ -, -NH-, -CO-, -NHCO-, -COO-, -(CH ₂ ) _m -,- SO ₂ -or a divalent organic group formed by any combination thereof. In particular, X is preferably a single bond, -O-, -NH- or -O-(CH ₂ ) _m -O-. Examples of "arbitrary combinations" include -O-(CH ₂ ) _m -O-, -O-C(CH ₃ ) ₂ -, -CO-(CH ₂ ) _m -, -NH-(CH ₂ ) _m －, －SO ₂ －(CH ₂ ) _m －, －CONH－(CH ₂ ) _m －, －CONH－(CH ₂ ) _m －NHCO－, －COO－(CH ₂ ) _m －OCO－, NH -(CH ₂ ) _m -NH-, -SO ₂ -(CH ₂ ) _m -SO ₂ -, etc. m represents an integer from 1 to 8. In addition, in the above-mentioned formula [N1], two Ys each independently represent a monovalent group selected from the side chain structure represented by the above-mentioned formulas [S1] to [S3].

In addition, in the above formula [N1], the positions of Y and X may be meta or ortho positions, preferably ortho positions. That is, the above formula [N1] is preferably the following formula [1'].

In addition, in the above formula [N1], _{the positions of the two amino groups (-NH 2} ) can be any position on the benzene ring, preferably the positions represented by the following formulas [1]-a1~[1]-a3 , The following formula [1]-a1 is preferred. In the following formula, X is the same as in the case of the above formula [N1]. In addition, the following formulas [1]-a1 to [1]-a3 are diagrams illustrating the positions of two amine groups, and the symbol Y shown in the above formula [N1] is omitted.

Therefore, if according to the above formula [1'] and [1]-a1~[1]-a3, the above formula [N1] can be selected from the following formulas [1]-a1-1~[1]-a3-2 Any one of the structure groups is preferable, and the structure represented by the following formula [1]-a1-1 is preferable. In the following formulae, X and Y are the same as in the case of formula [N1], respectively.

In addition, examples of the above-mentioned formulas [S1] to [S3] include the following formulas [S]-1 to [S]-20. Among them, examples of the above-mentioned formula [S1] are preferably the following formulas [S]-1 to [S]-4, [S]-8 or [S]-10. In addition, in the following formula, * represents the bonding position of the phenyl group in the above formula [1], [1'], and [1]-a1 to [1]-a3. In addition, in [S]-1~[S]-20, n is an integer from 1 to 20, and m is an integer from 1 to 6.

<Other diamines: diamines with photoreactive side chains> The diamine component of this embodiment may contain a diamine having a photoreactive side chain as another diamine. When the diamine component contains a diamine having a photoreactive side chain, a photoreactive side chain can be introduced into a specific polymer or other polymers. Specific examples of diamines having photoreactive side chains include, for example, the compounds described in paragraphs [0124] to [0132] of JP 2016/140328, but they are not limited thereto.

The diamines having these photoreactive side chains can be used alone or in combination of two or more. It can be used singly or in combination of two or more in accordance with the characteristics of liquid crystal alignment, pretilt angle, voltage retention characteristics, accumulated charge, etc. when the liquid crystal alignment film is made, and the liquid crystal response speed when making the liquid crystal display element. In the case of mixing two or more types, the ratio and the like may be appropriately adjusted.

In this embodiment, when a photoreactive side chain diamine is contained in the diamine component, the photoreactive side chain diamine is preferably 10 to 70 mole% of the total diamine component, and 10 to 60 mole% Ear% is better.

<Other diamines: Diamines other than the above> Other diamines that can be contained in the diamine component for obtaining the specific polymer are not limited to the above-mentioned diamines having photoreactive side chains and the like. In the case of producing a polyimide precursor and/or polyimine, diamines other than the above-mentioned diamines may be used in combination as the diamine component. Specifically, in addition to the following diamines, the compounds described in paragraph [0135] of the Japanese Patent Publication No. WO2016/140328 can be cited.

Diamines with photo-alignment groups such as 4,4'-diaminoazobenzene or diaminodiphenylacetylene; 4,4'-diaminodiphenylamine, 4,4'-diamino Diphenylmethylamine, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diamine Resorcinol; 4,4'-diamino-3,3'-dihydroxybiphenyl, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5- Diaminobenzoic acid and diamines having a carboxyl group such as diamines represented by the following formulas (3b-1) to (3b-4); 4-(2-(methylamino)ethyl)aniline, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indan-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1, 3,3-Trimethyl-1H-indene-6-amine; 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,N-diene Propylaniline; 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, a diamine represented by the following formula (Ds-1) and other diamines having a siloxane bond; The diamine represented by the following formula (Ox-1)~(Ox-2), 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6 -Diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, the diamine represented by the following formula (z-1) ~ formula (z-18) Diamines with heterocyclic structures; metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis (Aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), etc.

(上述(3b-1)中，A¹ 表示單鍵、－CH₂ －、－C₂ H₄ －、－C(CH₃ )₂ －、－CF₂ －、－C(CF₃ )₂ －、－O－、－CO－、－NH－、－N(CH₃ )－、－CONH－、－NHCO－、－CH₂ O－、－OCH₂ －、－COO－、－OCO－、－CON(CH₃ )－或－N(CH₃ )CO－，m1及m2各自獨立地表示0~4之整數，且m1＋m2表示1~4之整數。式(3b-2)中，m3及m4各自獨立地表示1~5之整數。式(3b-3)中，A² 表示碳數1~5之直鏈或分枝烷基，m5表示1~5之整數。式(3b-4)中，A³ 及A⁴ 各自獨立地表示單鍵、－CH₂ －、－C₂ H₄ －、－C(CH₃ )₂ －、－CF₂ －、－C(CF₃ )₂ －、－O－、－CO－、－NH－、－N(CH₃ )－、－CONH－、－NHCO－、－CH₂ O－、－OCH₂ －、－COO－、－OCO－、－CON(CH₃ )－或－N(CH₃ )CO－，m6表示1~4之整數。)

(In (3b-1) above, A ¹ represents a single bond, -CH ₂ -, -C ₂ H ₄ -, -C(CH ₃ ) ₂ -, -CF ₂ -, -C(CF ₃ ) ₂ -, －O－, －CO－, －NH－, －N(CH ₃ )－, －CONH－, －NHCO－, －CH ₂ O－, －OCH ₂ －, －COO－, －OCO－, －CON( CH ₃ )-or -N(CH ₃ )CO-, m1 and m2 each independently represent an integer from 0 to 4, and m1 + m2 represents an integer from 1 to 4. In formula (3b-2), m3 and m4 are each independently Represents an integer of 1 to 5. In formula (3b-3), A ² represents a linear or branched alkyl group with carbon number of 1 to 5, and m5 represents an integer of 1 to 5. In formula (3b-4), A ³ And A ⁴ each independently represent a single bond, -CH ₂ -, -C ₂ H ₄ -, -C(CH ₃ ) ₂ -, -CF ₂ -, -C(CF ₃ ) ₂ -, -O-,- CO-, -NH-, -N(CH ₃ )-, -CONH-, -NHCO-, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO-, -CON(CH ₃ )- or －N(CH ₃ )CO－, m6 represents an integer from 1 to 4.)

The above-mentioned other diamines may be used in one kind or a mixture of two or more kinds according to the characteristics of liquid crystal alignment, pretilt angle, voltage retention characteristics, accumulated charge and the like when the liquid crystal alignment film is formed.

When the liquid crystal alignment film of the present invention is used in an IPS type or FFS type liquid crystal display element, the diamine constituting the polyimide of (A) in the present invention is not used with a side chain group with a carbon number of 6 or more. Diamine is preferred. Examples of the diamine having a side chain group having 6 or more carbon atoms include the diamine having the above-mentioned specific side chain structure and the diamine having the two side chain type specific side chain structure exhibiting the above-mentioned vertical alignment.

＜Polyimide＞ The polyimide of the present invention is obtained by imidizing the polyimine precursor which is the reactant of the above-mentioned diamine and the tetracarboxylic acid component.

＜Tetracarboxylic acid component＞ The tetracarboxylic acid component used to obtain the polyimide of the present invention may use the tetracarboxylic dianhydride represented by the following formula [3] or its derivatives (tetracarboxylic acid, tetracarboxylic dihalide, tetracarboxylic acid Acid dialkyl ester or tetracarboxylic acid dialkyl ester dihalide) (These are collectively referred to as specific tetracarboxylic acid).

式[3]中，X₁ 為選自下述式(B-1)~(B-20)之任一者。尤其，X₁ 以(B-1)、(B-2)、(B-3)之任一者為佳。

In formula [3], X ₁ is any one selected from the following formulas (B-1) to (B-20). In particular, X ₁ is preferably any one of (B-1), (B-2), and (B-3).

(式中，j及k為0或1之整數，A₁ 及A₂ 各自獨立地表示單鍵、－O－、－CO－、－COO－、伸苯基、磺醯基或醯胺基。在上述式(B-20)之中兩個A₂ 可相同或相異。式中，*表示鍵結鍵。)

(In the formula, j and k are integers of 0 or 1, and A ₁ and A ₂ each independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or amide. In the above formula (B-20), two A ₂ can be the same or different. In the formula, * represents a bonding bond.)

Specific examples of specific tetracarboxylic acids include 2,3,3',4-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid, in addition to the following compounds Carboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, 3,3',4,4'-di Phenone tetracarboxylic dianhydride, 3,3',4,4'-diphenyl tetracarboxylic dianhydride.

The specific tetracarboxylic acid preferably occupies 50-100 mol% in 100 mol% of the total tetracarboxylic acid component. In particular, 70-100 mol% is preferable. More preferably, it is 80-100 mol%.

The specific tetracarboxylic acid can be used in one or two types according to the solubility of the specific polymer in the solvent or the coating property of the liquid crystal alignment agent, the liquid crystal alignment when the liquid crystal alignment film is made, the voltage retention rate, and the accumulated charge. Mix the above.

The tetracarboxylic acid component used to obtain the polyimide of the present invention may also contain tetracarboxylic acids other than the above-mentioned specific tetracarboxylic acid (hereinafter also referred to as other tetracarboxylic acid). Other tetracarboxylic acids include the tetracarboxylic acid compounds, tetracarboxylic dianhydrides, tetracarboxylic acid dihalide compounds, tetracarboxylic acid dialkyl ester compounds, or tetracarboxylic acid dialkyl ester dihalide compounds disclosed below. .

That is, other tetracarboxylic acids include 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-anthracene tetracarboxylic acid Acid dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 1,1,1,3,3,3- Hexafluoro-2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, bis(3,4-dicarboxyphenyl)dimethylsilane dianhydride, bis(3,4-dicarboxyphenyl) )Diphenylsilane dianhydride, 2,3,4,5-pyridinetetracarboxylic dianhydride, 2,6-bis(3,4-dicarboxyphenyl)pyridine dianhydride, 3,4,9,10- Perylene tetracarboxylic dianhydride or 1,3-diphenyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, etc. Other tetracarboxylic acids can be used in accordance with the solubility of the specific polymer in the solvent or the coating property of the liquid crystal alignment agent, the liquid crystal alignment when the liquid crystal alignment film is made, the voltage retention rate, and the accumulated charge. Mix the above.

＜Method for producing polyimide＞ The polyimide of the present invention is obtained by a method of reacting the diamine component and the tetracarboxylic acid component described above. The method may include, for example, reacting a diamine component containing one or more diamines with at least one tetracarboxylic acid component selected from the group consisting of tetracarboxylic dianhydride and derivatives of tetracarboxylic acid, and Method for obtaining polyamide acid. Specifically, a method of polycondensing primary or secondary diamine and tetracarboxylic dianhydride to obtain polyamide acid can be used.

In order to obtain polyalkyl amide acid esters, a polycondensation method of tetracarboxylic acid esterified with carboxyl dialkyl and primary or secondary diamine can be used; A method of polycondensation of a grade diamine; or a method of converting the carboxyl group of polyamide acid into an ester. In order to obtain a polyimide, a method of ring-closing the above-mentioned polyimide or polyalkylester to obtain a polyimide can be used.

The reaction of the diamine component and the tetracarboxylic acid component is usually carried out in a solvent. The solvent used at this time is not particularly limited as long as it can dissolve the polyimide precursor produced. Examples of solvents here include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethyl Acetamide, dimethyl sulfide, 1,3-dimethyl-2-imidazolinone, etc. In addition, when the polyimide precursor has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone or the following formula can be used Solvents etc. represented by [D-1] to [D-3].

In the formula [D-1], D ¹ represents an alkyl group having 1 to 3 carbon atoms. In the formula [D-2], D ² represents an alkyl group having 1 to 3 carbon atoms. In the formula [D-3], D ³ represents an alkyl group having 1 to 4 carbon atoms.

These solvents can be used alone or in combination of two or more. Even if it is a solvent that does not dissolve the polyimide precursor, as long as the generated polyimine precursor does not precipitate, it can be mixed with the above-mentioned solvent and used. In addition, the moisture in the solvent will hinder the polymerization reaction and even cause the produced polyimide precursor to be hydrolyzed. Therefore, the solvent is preferably dehydrated and dried.

When the diamine component and the tetracarboxylic acid component are reacted in a solvent, a solution in which the diamine component is dispersed or dissolved in the solvent is stirred, and the tetracarboxylic acid component is added directly or after being dispersed or dissolved in the solvent. The method; on the contrary, the method of adding the diamine component to the solution in which the tetracarboxylic acid component is dispersed or dissolved in the solvent; the method of alternately adding the diamine component and the tetracarboxylic acid component, etc., any of these methods can be used method. In addition, when the diamine component or the tetracarboxylic acid component is used for the reaction in plural, the reaction can be carried out in a pre-mixed state, or the reaction can be carried out separately, or even the low molecular weight form after the reaction can be made separately. Mix and react to make a polymer.

The temperature for the polycondensation of the diamine component and the tetracarboxylic acid component can be selected from any temperature of -20 to 150°C, preferably in the range of -5 to 100°C. The reaction can be carried out at any concentration. However, if the concentration is too low, it is difficult to obtain a polymer with a high molecular weight, and if the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring becomes difficult. Therefore, it is preferably 1-50% by mass, more preferably 5-30% by mass. The initial stage of the reaction is carried out at a high concentration, and then a solvent can be added.

In the polymerization reaction of the polyimide precursor, the ratio of the total moles of the diamine components to the total moles of the tetracarboxylic acid components is preferably 0.8 to 1.2. As in the usual polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the polyimide precursor produced.

Polyimine is a polyimide obtained by ring-closing the aforementioned polyimine precursor. In this polyimine, the ring-closure rate of the amide acid group (also called the imidization rate) is not necessarily If it is 100%, it can be adjusted arbitrarily according to the application or purpose. From the viewpoint of reducing the incidence of display defects, the polyimide rate of the specific polymer used in the present invention is preferably 20-100%, preferably 50-99%, and more preferably It is 70~95%. The method of making the polyimide precursor imidization includes thermal imidization in which the solution of the polyimide precursor is directly heated, or the catalyst is added to the solution of the polyimide precursor. Mediator imidization.

When the polyimide precursor is thermally imidized in the solution, the temperature is 100~400℃, preferably 120~250℃, so as to remove the water produced by the imidization reaction to the outside of the system at the same time. The method of reaction is better. The catalyst of the polyimide precursor can be imidized by adding alkaline catalyst and acid anhydride to the solution of the polyimide precursor, and the temperature is -20~250℃, preferably 0~180℃ Stir to proceed.

The amount of alkaline catalyst is 0.5 to 30 mole times of the amide acid group, preferably 2 to 20 mol times, and the amount of acid anhydride is 1 to 50 mole times of the amide acid group, preferably 3 to 30 mole times. Ear times. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. In particular, pyridine has moderate basicity to allow the reaction to proceed, so it is suitable. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. In particular, if acetic anhydride is used, the purification after the completion of the reaction is easy to proceed, so it is suitable. The rate of catalyst imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

In the case of recovering the produced polyimide from the reaction solution of polyimine, it is only necessary to add the reaction solution to a solvent to precipitate it. The solvent used for precipitation includes methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, water, and the like. The polymer precipitated by adding to the solvent can be dried under normal pressure or reduced pressure or under normal temperature or heating after filtration and recovery. In addition, the polymer recovered by precipitation is re-dissolved in the solvent, and if the re-precipitation recovery operation is repeated 2 to 10 times, the impurities in the polymer can be reduced. Examples of the solvent at this time include alcohols, ketones, and hydrocarbons. If three or more solvents selected from these are used, the efficiency of further purification is improved, so it is suitable.

＜Terminal modifier＞ When synthesizing the polyimide precursor or polyimide of the present invention, as described above, using the tetracarboxylic acid derivative component and the diamine component, and the appropriate terminal modifier, the terminal modified polymer can be synthesized. Things. The terminal-modified polymer has the effects of improving the film hardness of the liquid crystal alignment film obtained by coating, or improving the adhesion characteristics of the sealant and the liquid crystal alignment film. Examples of the polyimide precursor or the terminal of the polyimine in the present invention include an amino group, a carboxyl group, an acid anhydride group, an isocyanate group, a thioisocyanate group, or a derivative thereof. Amino groups, carboxyl groups, acid anhydride groups, isocyanate groups, and thioisocyanates can be obtained by a usual condensation reaction, and the above-mentioned derivatives can be obtained, for example, by modifying the terminal with the following terminal modifier.

The terminal modifiers include, for example, acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, The compound represented by the formula (m-1)~(m-6), 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4 ,5,6,7-Tetrafluoroisobenzofuran-1,3-dione, 4-ethynyl phthalic anhydride and other acid monoanhydrides;

Dicarbonate diester compounds such as di-tert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acrylic chloride, methacrylic acid chloride, and nicotinic acid chloride; aniline, 2-aminophenol , 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoin Acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine and other monoamine compounds; monoamine compounds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, etc. Isocyanate compounds; thioisocyanate compounds such as ethyl isothiocyanate and allyl isothiocyanate.

The use ratio of the terminal modifier is set at 0.01-20 mol parts, preferably 0.01-10 mol parts with respect to 100 mol parts in total of the diamine components used.

＜Liquid crystal alignment agent＞ The liquid crystal alignment agent of the present invention contains the above-mentioned polyimide (referred to as a specific polymer), but may contain two or more polymers with different structures. In addition, the polymer may also contain other polymers. The form of the polymer includes polyamide, polyimide, polyamide, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polyphenylene Ethylene or its derivatives, poly(styrene-phenylmaleimide) derivatives, poly(meth)acrylates and the like. In the case where the liquid crystal alignment agent of the present invention contains other polymers, the ratio of the specific polymer to the total polymer components is preferably 5% by mass or more, for example, 5-95% by mass.

Among the above-mentioned other polymers, from the viewpoint of improving the alignment of liquid crystals, in particular, polyamide acid without an imine ring structure or polyamide acid without an imine ring structure (hereinafter also referred to as Polyimide precursor (pa)) is preferred.

The tetracarboxylic acid derivative component used to obtain the polyimide precursor (pa) includes acyclic aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride or Its derivatives. Specific examples of acyclic aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride include the tetracarboxylic dianhydride or derivatives thereof exemplified in the above-mentioned specific polymer. Particularly suitable tetracarboxylic acid derivative components are preferably the compound represented by the above formula [3] or a derivative thereof. As the tetracarboxylic acid derivative component, one kind of tetracarboxylic dianhydride or its derivative can be used alone or in combination of two or more kinds.

Suitable examples of the tetracarboxylic acid derivative components used to obtain the polyimide precursor (pa) include X ₁ in the formula [3] selected from the above formulas (B-1) to (B-8), (B-13)-(B-20) Tetracarboxylic dianhydride represented by formula [3] or its derivative.

The use ratio of the tetracarboxylic dianhydride or its derivative represented by the above formula [3] is 1 mole relative to 1 mole of the all tetracarboxylic acid derivative component used in the synthesis of the polyimide precursor (pa) ~100 mol% is better, 5 to 100 mol% is better, and 10 to 100 mol% is more preferred.

The diamine component used to obtain the polyimide precursor (pa) includes the diamine component exemplified in the above-mentioned specific polymer. In particular, it contains a diamine selected from the group consisting of a urea bond, an amide bond, a carboxyl group and a hydroxyl group in the molecule (hereinafter also referred to as diamine (b1)), and has a diamine selected from The nitrogen-containing structure of the group consisting of a secondary amino group, a tertiary amino group and a heterocyclic ring (except for urea bonds, amide bonds, and amide bonds) of diamines (hereinafter also referred to as diamines (b2) At least one diamine in the group formed by) is preferred. The aforementioned diamine component may be used alone or in combination of two or more kinds. Among the above, the appropriate total amount of diamine (b1) and (b2) used is 10-100 mol% relative to the total amount of the diamine component used to make the polyimide precursor (pa). It is preferably 10 to 90 mol%, more preferably 20 to 80 mol%.

The polyimide precursor (pa) can be composed of one or more polyimide precursors. A more suitable specific aspect of the polyimide precursor (pa) may be selected from the group consisting of reactants of the diamine component containing the diamine (b1) and the diamine (b2) and the tetracarboxylic acid derivative component. At least one polymer from the group consisting of polyimide precursors (hereinafter also referred to as copolymers); selected from the group consisting of the above-mentioned diamine (b1) as a reactant of the diamine component and the tetracarboxylic acid derivative component At least one polyimine precursor (pa-p1) in the group consisting of polyimine precursors and selected from the group consisting of diamine components and tetracarboxylic acid derivatives containing the above-mentioned diamine (b2) A mixture of at least one polyimine precursor (pa-p2) in the group formed by the polyimine precursor of the reactant (hereinafter also referred to as a polymer blend). The above-mentioned copolymers or polymer blends can be used alone or in combination.

Among the above copolymers, the appropriate amount of diamine (b1) used is 30-100 mol%, preferably 40% relative to the total amount of the diamine component used to make the polyimide precursor (pa) ~100 mol%, more preferably 50~100 mol%. Among the above-mentioned copolymers, the appropriate amount of diamine (b2) used is 30-100 mol%, preferably 40% relative to the total amount of the diamine component used to make the polyimide precursor (pa) ~100 mol%, more preferably 50~100 mol%. Among the above polymer blends, the appropriate amount of diamine (b1) and diamine (b2) used is relative to the amount used to make the polyimide precursor (pa-p1) and polyimide precursor ( The total amount of the diamine component of pa-p2) is 20-100 mol%, respectively. The appropriate amount of diamine (b1) used is 20-90 mole% relative to the total amount of the diamine component used to make the polyimide precursor (pa-p1), more preferably 20-80 mole% %. The appropriate amount of diamine (b2) used is 20~80 mole% relative to the total amount of the diamine component used to make the polyimide precursor (pa-p2), more preferably 30~80 mole% %.

Specific examples of the above-mentioned diamine (b1) include the diamines represented by the above-mentioned formulas [d2-10]~[d2-16], 2,4-diaminophenol, 3,5-diaminophenol, 3 ,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diamino-3,3'-dihydroxybiphenyl , 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid or 3,5-diaminobenzoic acid, or the two represented by the above formula (3b-1) ~ formula (3b-4) amine.

Specific examples of the above-mentioned diamine (b2) are diamines represented by the above-mentioned formulas [d2-23]~[d2-28], 4,4'-diaminodiphenylamine, 4,4'-diamine Diphenylmethylamine and the diamines represented by the above-mentioned formulas (z-1) to (z-18) are preferred.

The mass ratio of the content of the polyimide precursor (pa-p1) to the content of the polyimide precursor (pa-p2) is preferably 5/95~95/5, preferably 10/90 ~90/10.

From the viewpoint of less residual image from residual DC, the content ratio of the polyimide of the specific polymer to the polyimide precursor (pa) is determined by [polyimide of the specific polymer]/[polyimide] The mass ratio of imine precursor (pa)] can be 5/95~95/5, or 20/80~90/10, or 20/80~80/20.

From the viewpoint of forming a uniform thin film, the liquid crystal alignment agent generally takes the form of a coating liquid. The liquid crystal alignment agent of the present invention is also preferably a coating liquid containing the above-mentioned polymer component and an organic solvent that dissolves the polymer component. At this time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed in accordance with the setting of the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, 1% by mass or more is preferable, and from the viewpoint of storage stability of the solution, 10% by mass or less is preferable. The concentration of a particularly suitable polymer is 2 to 8% by mass.

The organic solvents contained in the liquid crystal alignment agent include (B) butyl cellosolve and butyl cellosolve acetate, and others also contain other organic solvents that allow the polymer components to be uniformly dissolved. The liquid crystal alignment agent of the present invention contains butyl cellosolve and butyl cellosolve acetate, which are poor solvents, so that the liquids have excellent bonding properties, good film-forming properties, and can be used stably for a long time even in an inkjet method.

Relative to the total organic solvent contained in the liquid crystal alignment agent, the content of butyl cellosolve is preferably 5-20% by mass, and relative to the total organic solvent contained in the liquid crystal alignment agent, the content of butyl cellosolve acetate is preferably 5-20 mass% %. With respect to the total organic solvent contained in the liquid crystal alignment agent, the total amount of butyl cellosolve and butyl cellosolve acetate is preferably 10% by mass or more, preferably 12% by mass or more, and more preferably 15% by mass or more.

Other organic solvents are not particularly limited as long as they can dissolve the polymer component. If specific examples are given, there are N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyl lactamide, N-methyl-2-pyrrolidone, N -Ethyl-2-pyrrolidone, dimethyl sulfide, γ-butyrolactone, 1,3-dimethyl-2-imidazolinone, N-(n-propyl)-2-pyrrolidone, N-isopropyl -2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl- 2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, 3-methoxy-N,N-dimethyl Propanamide, 3-butoxy-N,N-dimethylpropaneamide, methyl ethyl ketone, cyclohexanone, cyclopentanone (also collectively referred to as "solvent (C1)"); diiso Propyl ether, diisobutyl ether, diisobutyl methanol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1 , 2-Butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethyl Dibutyl glycol ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol two Acetate, propylene carbonate, ethylene carbonate, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propane Alcohol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, two Ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate , Acetate propylene glycol monoethyl ether, 3-methoxy methyl propionate, 3-ethoxy ethyl propionate, 3-methoxy ethyl propionate, 3-methoxy propyl propionate, 3-methoxy Butyl propionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone) (also collectively referred to as ``solvent (C2)”) etc. Solvent (C1) especially to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone, 3-methoxy-N,N-dimethylpropaneamide, 3- Butoxy-N,N-dimethyl propaneamide, N,N-dimethyl lactamide, 1,3-dimethyl-2-imidazolinone are preferred. Relative to the total organic solvent contained in the liquid crystal alignment agent, the content of the solvent (C1) is preferably 60~90% by mass, more preferably 60~88% by mass, and particularly preferably 60~85% by mass. In addition, the solvent (C2) is especially diisobutyl methanol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl 2-pentanone or diisobutyl ketone is preferred. Relative to the total organic solvent contained in the liquid crystal alignment agent, the content of the solvent (C2) is preferably 1-20% by mass, and preferably 5-20% by mass. In the case of containing solvent (C1) and solvent (C2), relative to the total organic solvent contained in the liquid crystal alignment agent, the total content of solvent (C1) and solvent (C2) is preferably 60~90% by mass, 60~ 88% by mass is more preferred, and 60 to 85% by mass is particularly preferred.

In addition, the organic solvent contained in the liquid crystal alignment agent of the present invention, in addition to the above-mentioned solvents, can also be used to improve the coatability when the liquid crystal alignment agent is applied or the surface smoothness of the coating film. Specific examples of such organic solvents include, for example, the organic solvents described in paragraph [0177] of the Japanese Patent Publication No. WO2016/140328.

The liquid crystal alignment agent of the present invention may additionally contain components other than the polymer component and the organic solvent. Such additional components include adhesion assistants used to improve the adhesion between the liquid crystal alignment film and the substrate or the adhesion between the liquid crystal alignment film and the sealing material, crosslinking agents used to increase the strength of the liquid crystal alignment film, and A dielectric or conductive material that adjusts the permittivity or resistance of the liquid crystal alignment film. Specific examples of these additional components include the poor solvents or crosslinkable compounds disclosed in paragraph [0104] on page 53 to paragraph [0116] on page 60 of International Publication No. 2015/060357.

In addition to the above, the liquid crystal alignment agent of the present invention may contain polymers other than the specific polymers described in the present invention, and dielectric materials used to change the dielectric properties or conductivity of the liquid crystal alignment film. The silane coupling agent used to improve the adhesion between the liquid crystal alignment film and the substrate, the crosslinking compound used to increase the hardness or density of the liquid crystal alignment film when the liquid crystal alignment film is formed, and even when the coating film is fired It is used to effectively carry out the imidization of the polyimide precursor heated by the polyimide precursor, etc.

The compound that improves the adhesion between the liquid crystal alignment film and the substrate includes a compound containing a functional silane. Specific examples include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyl diethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2- Aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxy Silane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3 -Aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl- 1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazepine Nonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-amine Propyl triethoxysilane, N-phenyl-3-aminopropyl trimethoxysilane, N-phenyl-3-aminopropyl triethoxysilane, N-bis(oxyethylene)-3 -Aminopropyltrimethoxysilane, N-bis(oxyethylene)-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidyl ether Oxypropyl methyl diethoxy silane, 3-glycidoxy propyl triethoxy silane, p-styryl trimethoxy silane, 3-methacryloxy propyl methyl dimethyl dimethyl Oxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxy Silane, 3-propenyloxypropyltrimethoxysilane, ginseng-(trimethoxysilylpropyl) isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercapto Propyl trimethoxy silane, 3-isocyanate propyl triethoxy silane, or the compound described in paragraph [0180] of Japanese Patent Publication WO2016/140328. The content thereof is preferably 0.1-30 parts by mass, preferably 0.1-20 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

In addition, in order to further improve the film strength of the liquid crystal alignment film, it is also possible to add two or more selected from the group consisting of oxetane group, oxetanyl group, isocyanate protecting group, isothiocyanate protecting group, containing oxazole A group consisting of a morpholino ring structure, a group containing a Mildrum’s acid structure, a cyclocarbonate group and a hydroxyalkyl amide group consisting of at least one group of compounds (hereinafter also referred to as having two or more specific Cross-linking properties of phenolic compounds such as 2,2-bis(4-hydroxy-3,5-dimethylolphenyl)propane, tetra(methoxymethyl)bisphenol, etc. Compound. These crosslinkable compounds are preferably 0.1 to 30 parts by mass, and more preferably 1 to 20 parts by mass relative to 100 parts by mass of the total amount of the polymer contained in the liquid crystal alignment agent. The compounds having two or more specific crosslinkable groups include the following compounds.

＜Liquid crystal alignment film＞ The liquid crystal alignment film of the present invention is obtained from the above liquid crystal alignment agent. By using the liquid crystal alignment agent of the present invention, it is particularly suitable for the IPS type or FFS type that responds to the liquid crystal molecules aligned horizontally to the substrate by an electric field, and can provide excellent voltage retention, rapid relaxation of accumulated charges, and excellent after-image characteristics The liquid crystal alignment film or liquid crystal display element. If an example of a method of obtaining a liquid crystal alignment film is cited, the liquid crystal alignment agent of the present invention is applied to a substrate, and then dried and fired as necessary, and the obtained cured film can be directly used as a liquid crystal alignment film. In addition, the cured film can be rubbed, or irradiated with polarized light or light of a specific wavelength, or subjected to treatment such as ion beam, or can be used as an alignment film for PSA and in a state where a voltage is applied to a liquid crystal display element filled with liquid crystal Irradiate UV.

The substrate coated with the liquid crystal alignment agent is not particularly limited as long as it is a highly transparent substrate, and glass substrates, silicon nitride substrates, and plastic substrates such as acrylic substrates or polycarbonate substrates can be used. At this time, if a substrate on which ITO electrodes and the like for driving liquid crystals are formed is used, it is suitable from the viewpoint of simplification of the procedure. In addition, in a reflective liquid crystal display element, if it is a substrate with only one side, opaque objects such as silicon wafers can also be used. In this case, the electrode can use a material that reflects light, such as aluminum.

The coating method of the liquid crystal alignment agent is not particularly limited, and screen printing, offset printing, flexographic printing, inkjet methods, etc. are generally known in the industry. Other coating methods include immersion method, roll coating method, slit coating method, spin method, spray method, etc. These methods can be used according to the purpose. The liquid crystal alignment agent is coated on the substrate, and then the solvent is evaporated and fired by heating means such as a hot plate, a thermal cycle oven, an IR (infrared) oven, etc. The temperature and time can be arbitrarily selected for the drying and firing steps after coating the liquid crystal alignment agent. The drying step is not necessarily necessary, and when the time from coating to firing is not necessary for each substrate, or when it is not fired immediately after coating, it is better to perform the drying step. The drying only needs to remove the solvent to the extent that the shape of the coating film is not deformed by the transportation of the substrate or the like, and the drying means is not particularly limited. For example, a method of drying on a hot plate at a temperature of 40 to 150°C, preferably 60 to 100°C, for 0.5 to 30 minutes, preferably 1 to 5 minutes, can be mentioned.

In the case of using the liquid crystal alignment agent of the present invention, especially in the case of coating in the inkjet method, by containing butyl cellosolve and butyl cellosolve acetate as poor solvents, even if the standby spraying is performed for a long time, the polyamide Adhesion of the liquid of the imine solution to the surface of the inkjet head is also suppressed, so it does not deposit on the head and can be ejected stably.

The firing temperature of the coating film formed by applying the liquid crystal alignment agent is not limited, and is, for example, 100 to 350°C, preferably 120 to 300°C, and more preferably 150 to 250°C. The firing time is 5 to 240 minutes, preferably 10 to 90 minutes, and preferably 20 to 90 minutes. Heating can be performed by a generally known method, such as a hot plate, a hot air circulating furnace, an infrared furnace, and the like.

If the thickness of the liquid crystal alignment film after firing is too thin, the reliability of the liquid crystal display element may decrease. Therefore, 5 to 300 nm is preferable, and 10 to 200 nm is more preferable. The liquid crystal alignment film of the present invention is particularly useful as a liquid crystal alignment film of an IPS type or FFS type liquid crystal display element.

＜Liquid crystal display element and its manufacturing method＞ In the liquid crystal display element, after forming a liquid crystal alignment film on a substrate by the above-mentioned method, a liquid crystal cell can be produced by a well-known method. A specific example of a liquid crystal display element is a horizontal alignment type liquid crystal display element, which is provided with a liquid crystal cell having: two substrates arranged oppositely; a liquid crystal layer arranged between the substrates; and a liquid crystal layer arranged between the substrate and the liquid crystal layer , The above-mentioned liquid crystal alignment film formed by a liquid crystal alignment agent. Specifically, the liquid crystal alignment agent is coated on two substrates and fired, and then the alignment treatment is performed by rubbing treatment or photo-alignment treatment. In addition, it can be made into liquid crystal alignment without the alignment treatment for vertical alignment applications. Membrane to use. Two substrates are arranged in such a way that these liquid crystal alignment films are opposed to each other, and a liquid crystal layer composed of liquid crystal is sandwiched between the two substrates, even if they contact the liquid crystal alignment film to provide the liquid crystal layer to produce a liquid crystal cell, The horizontal alignment type liquid crystal display element will have such a liquid crystal cell.

The substrate of the liquid crystal display element is not particularly limited as long as it is a highly transparent substrate, and it is usually a substrate on which a transparent electrode for driving liquid crystal is formed. Specific examples include the same substrates as those described in the above-mentioned liquid crystal alignment film. A transparent glass substrate is prepared, a common electrode is provided on one of the substrates, and a segment electrode is provided on the other substrate. These electrodes can be made into, for example, ITO electrodes, and can be patterned to achieve the desired image display. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film can be set to, for example, a SiO ₂ -TlO ₂ film formed by a sol-gel method.

In addition, among high-performance elements such as TFT-type elements, a transistor-like element formed between the liquid crystal driving electrode and the substrate is used.

In the case of a transmissive liquid crystal display element, the above-mentioned substrate is generally used, and in the case of a reflective liquid crystal display element, if it is a single-sided substrate, an opaque substrate such as a silicon wafer can also be used. At this time, the electrode formed on the substrate can use a material that can reflect light, such as aluminum.

The liquid crystal material constituting the liquid crystal layer of the liquid crystal display element is not particularly limited. The liquid crystal material used in the conventional horizontal alignment method can be, for example, positive liquid crystal such as MLC-3019 manufactured by Merck or MLC-7026 manufactured by the same company. -100 negative type liquid crystal. In addition, in the case of the PSA mode, for example, a liquid crystal containing a polymerizable compound represented by the following formula can be used.

As a method of sandwiching the liquid crystal layer between two substrates, well-known methods can be cited. For example, preparing a pair of substrates on which a liquid crystal alignment film is formed, dispersing spacers such as beads on the liquid crystal alignment film of one of the substrates, and laminating the other substrate with the liquid crystal alignment film formed on the inner side. A method of injecting and sealing under reduced pressure. In addition, prepare a pair of substrates on which a liquid crystal alignment film is formed, spread spacers such as beads on the liquid crystal alignment film of one of the substrates, and then drop liquid crystals, and then attach the other substrate with the side where the liquid crystal alignment film is formed as the inside. And the method of sealing can also produce liquid crystal cells. The thickness of the aforementioned spacer is preferably 1 to 30 μm, preferably 2 to 10 μm.

The step of applying a voltage to the liquid crystal alignment film and the liquid crystal layer while irradiating ultraviolet rays to produce a liquid crystal cell can be mentioned, for example, by applying a voltage between the electrodes provided on the substrate to apply an electric field to the liquid crystal alignment film and the liquid crystal layer, and maintaining the electric field The method of irradiating ultraviolet light in the state. Here, the voltage applied between the electrodes is, for example, 5-30Vp-p, preferably 5-20Vp-p. The irradiation amount of ultraviolet rays is, for example, 1 to 60 ^{J/cm 2} , preferably 40 J/cm ² or less. When the amount of ultraviolet irradiation is low, the reliability reduction caused by the destruction of the components constituting the liquid crystal display element can be suppressed, and the ultraviolet rays can be reduced. The irradiation time improves the manufacturing efficiency, so it is suitable.

If a voltage is applied to the liquid crystal alignment film and the liquid crystal layer while irradiating ultraviolet rays as described above, the polymerizable compound will react to form a polymer. With this polymer, the tilt direction of the liquid crystal molecules can be memorized, and the obtained product can be accelerated. The response speed of the liquid crystal display element. In addition, if a voltage is applied to the liquid crystal alignment film and the liquid crystal layer while irradiating ultraviolet rays, it is selected from polyimide precursors having side chains for vertically aligning liquid crystals and photoreactive side chains, and polyimide precursors. The photoreactive side chains of the at least one polymer of the polyimine obtained by the imidization or the photoreactive side chains of the polymer react with the polymerizable compound, so that the production speed can be accelerated. The response speed of the obtained liquid crystal display element.

Next, set up the polarizer. Specifically, it is preferable to attach a pair of polarizing plates to the surfaces of the two substrates on the opposite side to the liquid crystal layer.

In addition, the liquid crystal alignment film and the liquid crystal display element of the present invention, as long as the liquid crystal alignment agent of the present invention is used, are not limited by the above-mentioned structure or manufacturing method, and may be manufactured by other well-known means. The procedure of obtaining a liquid crystal display element from a liquid crystal alignment agent is disclosed in, for example, paragraph [0074] on page 17 of Japanese Patent Application Laid-Open No. 2015-135393 to paragraph [0082] on page 19, etc.

In the case of a polymer photoreactive side chain, by polymerizing the polymerizable compound, and reacting the photoreactive side chains or the photoreactive side chain of the polymer with the polymerizable compound, it will be more efficient The alignment of the liquid crystal is fixed, and it becomes a liquid crystal display element excellent in response speed. [Example]

Examples are listed below to further illustrate the present invention in detail, but the present invention is not limited thereto. The abbreviations of the following compounds and the measurement methods of each characteristic are as follows.

(Diamine)

(Tetracarboxylic dianhydride)

(Terminal modifier) Boc ₂ O: Di-tertiary butyl dicarbonate

(additive)

s-1: 3-glycidoxypropyl triethoxysilane (organic solvent) NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: ethylene glycol monobutyl ether BCA: ethylene glycol monobutyl ether acetate DME: Dipropylene glycol dimethyl ether PB: Propylene glycol monobutyl ether

＜Measurement of imidization rate＞ Put 20 mg of polyimide powder into an NMR sample tube (NMR sample tube standard type, ϕ5 (manufactured by Kusano Science Co.)), and add deuterated dimethyl sulfide (DMSO-d6, 0.05% TMS (tetramethyl silane)) Mixture) (0.53ml), apply ultrasonic vibration to completely dissolve. This solution was measured for proton NMR at 500 MHz with an NMR measuring machine (JNW-ECA500) (manufactured by JEOL DATUM). The rate of imidization is based on the proton from the structure that does not change before and after imidization as the reference proton, using the peak cumulative value of this proton and the proton peak derived from the NH group of amidic acid that appears near 9.5 to 10.0 ppm The cumulative value is obtained by the following formula. The imidization rate (%) = (1-α･x/y)×100 In the above formula, x is the cumulative value of the proton peak derived from the NH group of the amide acid, y is the cumulative value of the peak proton of the reference proton, and α is in the case of polyamide acid (the imidation rate is 0%), The ratio of the number of reference protons to the protons of an NH group of a amic acid.

[Synthesis of polymer] <Synthesis Example 1> Weigh DA-1 10.3g (42-5mmol), DA-3 7.8g (14.0mmol) and DA-4 4.78g (14-0mmol) until they are stirred In the four-necked flask of the device and the nitrogen introduction tube, NMP was added so that the solid content concentration was 15% by mass, and the nitrogen was blown while stirring to dissolve it. While stirring this diamine solution, 10.2 g (45.5 mmol) of CA-1 was added, and NMP was further added so that the solid content concentration became 18% by mass. After stirring at 40°C for 1 hour, 3.57 g (18.2 mmol) of CA-2 was added at room temperature, and NMP was further added so that the solid content concentration became 18% by mass. This polymerization solution was stirred for 3 hours to obtain a polyamide acid solution (PA-1). Take 100.0 g of the obtained polyamide acid solution (PA-1) into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and add 4.06 g (18.6 mmol) of the _{terminal modifier Boc 2 O to 40} After stirring for 15 hours at °C, a terminal modified polyamide solution (PAboc-1) was obtained. Take 100.0 g of the polyamide acid solution (PAboc-1) that has been modified above into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, add NMP to make the solid content concentration 12% by mass, and Stir for 30 minutes. 10.54 g of acetic anhydride and 2.72 g of pyridine were added to the obtained polyamide acid solution, and after stirring at room temperature for 30 minutes, it was heated and stirred at 55°C for 2 hours and 15 minutes to perform chemical imidization. The obtained reaction liquid was added to methanol in an amount of 3.5 times the mass of the reaction liquid under stirring, and the deposited precipitate was filtered, and then washed with methanol three times. The obtained resin powder was vacuum dried at 80°C for 12 hours to obtain a powder of polyimide (SPI1-1). The imidization rate of this polyimide resin powder was 75%. NMP was added to the obtained polyimide (SPI1-1) so that the solid content concentration was 15% by mass, and the mixture was stirred at 70°C for 15 hours to obtain a polyimide (SPI1- 1) The solution.

<Synthesis Example 2> Weigh 4.18g (10.5mmol) of DA-2, 2.92g (5.2mmol) of DA-3, and 5.63g (19.3mmol) of DA-5 into a four-necked flask equipped with a stirring device and a nitrogen introduction tube , NMP was added so that the solid content concentration became 19% by mass, and nitrogen was blown while stirring to dissolve it. While stirring this diamine solution, 4.51 g (22.7 mmol) of CA-5 was added, and NMP was further added so that the solid content concentration was 20% by mass. After stirring at 50°C for 1 hour, 2.31 g (11.8 mmol) of CA-2 was added at room temperature, and NMP was further added so that the solid content concentration was 20% by mass. The polymerization solution was stirred for 3 hours to obtain a polyamide acid solution (PA-11). Take 50.0 g of the obtained polyamide acid solution (PA-11) into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and add 0.30 g (1.37 mmol) of the _{terminal modifier Boc 2 O to 40} After stirring for 15 hours at °C, a terminal modified polyamide solution (PAboc-11) was obtained. Take 50.0 g of the above-mentioned end-modified polyamide acid solution (PAboc-11) into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, add NMP to make the solid content concentration 12% by mass, and Stir for 30 minutes. 6.40 g of acetic anhydride and 2.12 g of pyridine were added to the obtained polyamide acid solution, and after stirring at room temperature for 30 minutes, it was heated and stirred at 60°C for 4 hours to perform chemical imidization. The obtained reaction liquid was added to methanol in an amount of 3.5 times the mass of the reaction liquid under stirring, and the deposited precipitate was filtered, and then washed with methanol three times. The obtained resin powder was vacuum dried at 80°C for 12 hours to obtain a powder of polyimide (SPI1-2). The imidization rate of this polyimide resin powder was 95%. NMP was added to the obtained polyimide (SPI1-2) so that the solid content concentration was 15% by mass, and the mixture was stirred at 70° C. for 15 hours to obtain a polyimide (SPI1- 2) The solution.

＜Synthesis example 3＞ Weigh 20.2 g (47.9 mmol) of DA-9 and 6.35 g (32.0 mmol) of DA-7 into a four-necked flask equipped with a stirring device and a nitrogen introduction tube, add NMP to make the solid content concentration 9% by mass, and blow nitrogen simultaneously Stir to dissolve. While stirring this diamine solution, 15.3 g (78.0 mmol) of CA-2 was added, and NMP was further added so that the solid content concentration became 12% by mass. This polymerization solution was stirred for 5 hours to obtain a polyamide acid solution (PAA2-1).

＜Synthesis example 4＞ Weigh 14.3 g (47.9 mmol) of DA-10 and 4.81 g (32.0 mmol) of DA-11 into a four-necked flask equipped with a stirring device and a nitrogen inlet tube, add NMP to make the solid content concentration 15% by mass, and blow nitrogen simultaneously Stir to dissolve. While stirring this diamine solution, 6.67 g (34.0 mmol) of CA-2 was added, and NMP was further added so that the solid content concentration was 15% by mass. After stirring at room temperature for 2 hours, 10.0 g (40.0 mmol) of CA-4 was added, and NMP was further added so that the solid content concentration was 15% by mass. This polymerization solution was stirred at 50°C for 12 hours to obtain a polyamide acid solution (PAA2-2).

＜Synthesis example 5＞ Weigh 29.3g (148mmol) of DA-7, 46.8g (111mmol) of DA-9 and 12.0g (111mmol) of DA-12 into a four-necked flask equipped with a stirring device and a nitrogen introduction tube, and add 451g of NMP and 194g of GBL, Blow nitrogen gas while stirring to dissolve it. While stirring this diamine solution under water cooling, 55.1 g (281 mmol) of CA-2 and GBL were added so that the solid content concentration was 14.5% by mass, and the solution was stirred under a nitrogen atmosphere and water cooling for 2 hours. In addition, 16.1 g (74.0 mmol) of CA-3 was added, GBL was further added to make the solid content concentration 15%, and the solid content concentration was 15% and NMP/GBL=50/ by stirring at 50°C for 15 hours in a nitrogen atmosphere. 50 (mass ratio) polyamide acid solution (PAA2-3).

＜Synthesis example 6＞ 7.45 g (26.0 mmol) of DA-8 was weighed into a four-necked flask equipped with a stirring device and a nitrogen introduction tube, 60.2 g of NMP was added to make the solid content concentration 11% by mass, and nitrogen was blown while stirring to dissolve it. While stirring the diamine solution under water cooling, 5.16 g (23.6 mmol) of CA-3 and NMP were added to make the solid content concentration 12%, and the polymerization solution was stirred at 50°C for 15 hours to obtain a polyamide acid solution (PAA2-4).

<Synthesis Example 7> 7.97 g (40.0 mmol) of DA-6 was weighed into a four-necked flask equipped with a stirring device and a nitrogen introduction tube, 55.6 g of NMP and 59.1 g of GBL were added, and nitrogen was blown while stirring to dissolve. While stirring this diamine solution under water cooling, 6.37 g (32.5 mmol) of CA-2 was added, and 31.3 g of NMP was further added, and while blowing nitrogen gas, it was stirred under water cooling for 3 hours. Next, DA-7 1.98g (10.0mmol) and GBL 13.9g were added, and after stirring and dissolving, CA-6 3.00g (10.0mmol) and GBL 13.9g were added, and nitrogen was blown while stirring under water cooling for 3 hours, and A polyamide acid solution (PAA2-5) with a solid content concentration of 10% and NMP/GBL=50/50 (mass ratio) was obtained.

＜Synthesis example 8＞ Weigh 16.4g (82.5mmol) of DA-7 and 16.4g (82.5mmol) of DA-6 into a four-necked flask equipped with a stirring device and a nitrogen introduction tube, add 240.5g of NMP, blow nitrogen while stirring to dissolve it . While stirring this diamine solution under water cooling, 20.6 g (82.5 mmol) of CA-4 and NMP were added so that the solid content concentration was 15.0% by mass, and the solution was stirred at 50° C. for 5 hours in a nitrogen atmosphere. In addition, 22.4 g (76.2 mmol) of CA-7 was added, and NMP was further added to make the solid content concentration 15%, and the mixture was stirred at 50°C for 15 hours in a nitrogen atmosphere to obtain a polyamide acid solution with a solid content of 15% ( PAA2-6) solution.

[Preparation of liquid crystal alignment agent] <Example 1> The polyimide (SPI1-1) solution obtained in Synthesis Example 1, the polyimide solution (PAA2-1) obtained in Synthesis Example 3, and the polyimide solution (PAA2-) obtained in Synthesis Example 4 were used. 2) Dilute with NMP, GBL, BCS, and BCA, add compound c-1 so that it becomes 3 parts by mass relative to 100 parts by mass of the entire polymer, and further make it 1 relative to 100 parts by mass of the entire polymer Compound s-1 was added in parts by mass, and stirred at room temperature. Next, the obtained solution was filtered with a filter with a pore size of 0.5 μm, and the composition ratio of the obtained polymer was (SPI1-1): (PAA2-1): (PAA2-2)=30:40:30 ( Solid content conversion mass ratio), solvent composition ratio NMP:GBL:BCS:BCA=30:45.9:5:15 (mass ratio), and a liquid crystal alignment agent (1) with a polymer solid content concentration of 4.1% by mass. No abnormalities such as turbidity or precipitation were observed in this liquid crystal alignment agent, and it was confirmed that it was a uniform solution.

<Examples 2-8, Comparative Examples 1-7> In accordance with the ratio of the polymer and the solvent shown in Table 1 below, the solutions obtained in Synthesis Examples 1 to 8 were used to obtain liquid crystal alignment agents (2) to (15) in the same manner as in Example 1.

[Printability Evaluation] The liquid crystal alignment agents (1) to (15) obtained above were filtered with a filter membrane with a pore size of 1.0 μm, and then filled in an inkjet printer (manufactured by Ishii Motor Co., Ltd., IP-1212NC1180L), and various evaluations were performed.

1. Evaluation of initial coatability Coating on the chromium-deposited glass substrate at scanning speed: 500mm/sec, meniscus value: -4500Pa, coating area: 65mm (scanning vertical direction) x 75mm (scanning parallel direction), Leave it at 23°C for 35 seconds. Then, it was dried on a hot plate at 90°C for 2 minutes, and then fired in a hot air circulating oven at 230°C for 20 minutes to obtain a substrate with a polyimide film with a film thickness of 600 Å. In addition, when each liquid crystal alignment agent is applied, the scanning pitch uses an inherent value to make the film thickness the same. Next, the obtained board|substrate with a film was observed visually and an optical microscope (Nikon make, ECLIPSE L300ND). If a uniform film is formed, it is defined as "good", and when spots or streaks are observed, it is defined as "bad" for evaluation.

2. Evaluation of ejection stability Perform standby spraying for a long time, and evaluate the leakage, precipitation and coatability of the nozzle surface. The standby ejection is a step of periodically ejecting liquid in order to suppress clogging of the nozzle.

(1) Liquid leakage on the surface of the nozzle Standby spraying for 15 hours at an interval of 1 minute and spraying time of 3 seconds, and then visually observe the surface of the nozzle. The case where the liquid does not leak from the nozzle of the nozzle is defined as "good" and the case where the liquid adheres to the surface of the nozzle is defined as " Bad" for evaluation. (2) Coatability Then, in the same manner as in the evaluation of the initial coatability described above, a substrate with a polyimide film having a film thickness of 600 Å was obtained, and it was observed visually and with an optical microscope. If a uniform film is formed, it is defined as "good", and the occurrence of streaks is defined as "bad" for evaluation. (3) Precipitates on the surface of the nozzle In addition, after wiping the surface of the nozzle with a cloth (AS ONE, ASPURE Wiper AS-909), visual observation and optical microscope observation of the cloth surface were performed, and the case where no precipitate was observed was defined as "good", and the case where the precipitate was observed The situation is defined as "bad" for evaluation.

The evaluation results of the respective liquid crystal alignment agents of the foregoing Examples 1 to 8 and Comparative Examples 1 to 7 as described above are disclosed in Table 2 below.

In the evaluation of the initial coatability of the liquid crystal alignment agents of Comparative Examples 2 and 5, scaly spots were generated due to insufficient bonding of the liquids, which was "bad". In addition, for the liquid crystal alignment agents of Comparative Examples 1, 3, 4, and 6, in the evaluation of ejection stability, liquid leakage and precipitates were observed on the ejection head after a long-term standby ejection, and streaks along the scanning direction were observed. Is "bad". In addition, liquid leakage was observed in the liquid crystal alignment agent of Comparative Example 7, but no precipitate was observed, and no streaks or spots were observed. On the other hand, in the liquid crystal alignment agent of the example, no streaks or spots were observed at the initial stage and after long-term standby spraying, and no liquid leakage or precipitation was observed on the surface of the spray head.

Regarding the liquid crystal alignment agents of Example 3 and Comparative Examples 4, 5, and 6, in the evaluation of the initial coatability described above, the polyimide film on the obtained substrate was scanned in the vertical direction and the horizontal direction. . In addition, 65mm was subtracted from the length measurement value in the vertical direction of the scan, and 75mm was subtracted from the length measurement value in the horizontal direction, and the average value was calculated as the wet spread of the liquid in the coating area. That is to say, the smaller the value, the better the dimensional stability. The evaluation results are disclosed in Table 3 below.

Example 3 has a small expansion similarly to Comparative Examples 4 to 6, and has good dimensional stability.

In addition, the liquid crystal alignment agents of Examples 1 to 8 can be used to produce liquid crystal display elements without alignment defects by a well-known method.

Claims (20)

A liquid crystal alignment agent containing the following (A), (B), (A): as a diamine component containing at least one diamine selected from the following formula [1] and formula [2] and tetracarboxylic acid The polyimide precursor of the reactant of the acid component is the polyimide obtained by the imidization of the polyimide,

In the formula, A ₁ is a single bond, a methylene group, an ether bond, an ester bond, an amide bond, a cyclohexylene group or an alkylene group with 2 to 20 carbon atoms. However, any of the alkylene groups -CH _2- Can be substituted by ether group, ester group, amide group, cyclohexylene, phenylene, ureido, amino or urethane group, any hydrogen atom of the amide group, the ureido group and the amino group May be substituted by methyl or tertiary butoxycarbonyl, A ₂ is a fluorine atom or a C1-C5 alkyl or alkoxy group, and any hydrogen atom of the alkyl group or the alkoxy group may be substituted by a fluorine atom , Any carbon atom can be substituted by an amine group protected by a tertiary butoxycarbonyl group, the plural a are each independently an integer of 0-4, and A ₂ may be the same or different _{when there is a plural A 2, b} And c are each independently an integer of 0-2, and when b is 0, c is 1 or 2 and A ₁ is an alkylene group, (B): an organic solvent containing butyl cellosolve and butyl cellosolve acetate. Such as the liquid crystal alignment agent of claim 1, wherein in the aforementioned formulas [1] and [2], A ₁ is a single bond, a methylene group, an ether bond, an ester bond or an alkylene group with 2 to 10 carbon atoms (however, the At least one -CH ₂ -of the alkylene group is substituted by an ether group or an ester group), A ₂ is CH ₃ , a is an integer of 0 to 1, b is 1, and c is an integer of 1 to 2. The liquid crystal alignment agent of claim 1, wherein the diamine represented by the above formula [1] and the diamine represented by the formula [2] are the following formulas [d1-1]~[d1-2] or [d2-1 Any structure of ]~[d2-28],

(In the formula [d1-1], R is a fluorine atom or an alkyl group or alkoxy group with a carbon number of 1 to 5, and any hydrogen atom of the alkyl group or the alkoxy group may be substituted with a fluorine atom, and the formula [d1- 2], Boc represents the third butoxycarbonyl group)

(In formula [d2-8], R and R'are each independently a fluorine atom or a C1-C5 alkyl or alkoxy group, and any hydrogen atom of the alkyl group or the alkoxy group may be substituted by a fluorine atom )

(In the formula, Boc represents the tertiary butoxycarbonyl group. When there is a plural m in the formula [d2-17], the plural m may be the same or different)

The liquid crystal alignment agent of claim 1, wherein the content of the diamine represented by the aforementioned formula [1] and the aforementioned formula [2] is 50 mol% or more relative to 1 mol of the total diamine component. The liquid crystal alignment agent according to claim 1, wherein the diamine component used in the polyimide does not use a diamine having a side chain group with a carbon number of 6 or more. The liquid crystal alignment agent of claim 1, wherein the diamine component used in the polyimide is two or more diamines represented by the formula [2]. The liquid crystal alignment agent of claim 1, wherein the tetracarboxylic acid component of (A) is represented by the following formula [3],

In the formula, X ₁ is any one of the following formulas (B-1) to (B-20),

(In the formula, j and k are integers of 0 or 1, and A ₁ and A ₂ each independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl or amide group, In the above formula (B-20), two A ₂ can be the same or different, and * represents a bonding bond). The liquid crystal alignment agent of claim 2, wherein the tetracarboxylic acid component of (A) is represented by the following formula [3],

In the formula, X ₁ is any one of the following formulas (B-1) to (B-18),

. The liquid crystal alignment agent of claim 7, wherein X ₁ of the above formula [3] is any one of the above formulas (B-1), (B-2), and (B-3). The liquid crystal alignment agent of claim 8, wherein X ₁ of the above formula [3] is any one of the above formulas (B-1), (B-2), and (B-3). The liquid crystal alignment agent of claim 1, wherein the polyimide has an imidization rate of 70-95%. The liquid crystal alignment agent of claim 1, wherein the aforementioned polyimine is a terminal-modified polyimine. The liquid crystal alignment agent of claim 1, wherein the aforementioned liquid crystal alignment agent further comprises a polyamide acid without an imine ring structure or a polyamide ester without an imine ring structure. The liquid crystal alignment agent of claim 1, wherein the content of butyl cellosolve is 5-20% by mass relative to the total organic solvent contained in the liquid crystal alignment agent, and the butyl cellosolve acetic acid is relative to the total organic solvent contained in the liquid crystal alignment agent. The content of ester is 5-20% by mass. The liquid crystal alignment agent of claim 14, wherein the aforementioned organic solvent further comprises selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, 3-methoxy-N,N -Dimethyl propane amide, 3-butoxy-N,N-dimethyl propane amide, N,N-dimethyl lactamide, 1,3-dimethyl-2-imidazolinone Either solvent (C1). The liquid crystal alignment agent of claim 15, which contains 60 to 90% by mass of the solvent (C1) of claim 15 relative to the total organic solvent contained in the liquid crystal alignment agent. The liquid crystal alignment agent of claim 16, wherein the aforementioned organic solvent further comprises selected from the group consisting of diisobutyl methanol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol dimethyl ether. Solvent for any of ether, 4-hydroxy-4-methyl-2-pentanone or diisobutyl ketone (C2). The liquid crystal alignment agent of claim 1, wherein the aforementioned liquid crystal alignment agent further comprises a crosslinkable compound and/or a compound containing a functional silane. A liquid crystal alignment film obtained from the liquid crystal alignment agent of any one of claims 1-18. A liquid crystal display element having the liquid crystal alignment film of claim 19.