TW202305037A - Liquid crystal alignment agent for optical alignment, liquid crystal alignment film and manufacturing method thereof, and liquid crystal element capable of forming a liquid crystal element with good contrast and excellent display quality even when the exposure energy for optical alignment processing is small - Google Patents

Abstract

The present invention provides a liquid crystal alignment film capable of forming a liquid crystal element with good contrast and excellent display quality even when the exposure energy for optical alignment processing is small, and provides a method for manufacturing the liquid crystal alignment film and a liquid crystal alignment agent for optical alignment that can form the liquid crystal alignment film. A liquid crystal alignment agent for optical alignment contains at least one polymer and a solvent. In the liquid crystal alignment agent for optical alignment, at least one of the polymers is a polymer obtained by reacting tetracarboxylic dianhydrides and diamines. The raw material composition used as the raw material for the reaction of tetracarboxylic dianhydrides with diamines to obtain a polymer contains at least one compound represented by formula (1-1) or formula (1-2) and a compound having a photoreactive structure that imparts liquid crystal alignment to the alignment film by photoreaction.

Description

Liquid crystal alignment agent for photo-alignment, liquid crystal alignment film and manufacturing method thereof, and liquid crystal element

The invention relates to a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal element using the liquid crystal alignment film. In detail, it is about a liquid crystal alignment agent for photo-alignment (hereinafter, sometimes abbreviated as liquid crystal alignment agent) used to form a liquid crystal alignment film (hereinafter, sometimes abbreviated as photo-alignment film), using the described A liquid crystal alignment film in a photo-alignment mode formed by using a liquid crystal alignment agent and a liquid crystal display element with the liquid crystal alignment film.

There is known a liquid crystal element, which can cause optical phenomena such as refraction, scattering, and reflection to electromagnetic waves incident into the element by controlling or modulating the alignment state of the liquid crystal layer in the element. Specifically, liquid crystal antennas, dimming windows, optical compensation materials, and variable phase shifters are known in addition to the following liquid crystal display elements.

As liquid crystal display elements, there are known twisted nematic (Twisted Nematic, TN) mode, super twisted nematic (Super Twisted Nematic, STN) mode, in-plane switching (In-Plane Switching, IPS) mode, fringe field switching (Fringe Field Switching (FFS) mode, vertical alignment type Vertical Alignment (Vertical Alignment, VA) (Multi-domain Vertical Alignment) mode and other liquid crystal display elements with various driving methods. These liquid crystal display elements are used in image display devices of various electronic devices such as televisions and mobile phones, and are being developed with the aim of further improving display quality. Specifically, the improvement of the performance of the liquid crystal display element can be achieved not only by the improvement of the driving method and the structure of the element, but also by the constituent members used in the element. Moreover, among the structural members used in liquid crystal display elements, especially the liquid crystal alignment film is one of the important materials related to the display quality. Actively conduct research.

Here, the liquid crystal alignment film is provided on a pair of substrates arranged on both sides of the liquid crystal layer of the liquid crystal display element, and is arranged in contact with the liquid crystal layer, and has the function of aligning the liquid crystal molecules constituting the liquid crystal layer with a certain regularity with respect to the substrates. function. By using a liquid crystal alignment film with high liquid crystal alignment, a liquid crystal display element with high contrast and improved afterimage characteristics can be realized (for example, refer to Patent Document 1 and Patent Document 2).

In the formation of such a liquid crystal alignment film, a solution (varnish) obtained by dissolving polyamic acid, soluble polyimide, or polyamic acid ester in an organic solvent is currently mainly used. When using these varnishes to form a liquid crystal alignment film, the varnish is coated on a substrate, and then the coating film is cured by heating or the like to form a polyimide-based liquid crystal alignment film, and alignment suitable for the display mode is performed if necessary. deal with. As an alignment treatment method, there are known: a rubbing method in which the orientation of polymer molecules is adjusted by rubbing the surface of the alignment film with a cloth; and photoisomerization in the polymer molecules by irradiating linearly polarized ultraviolet rays to the alignment film. Or dimerization and other photochemical changes, the photoalignment method that imparts anisotropy to the film, among them, compared with the rubbing method, the alignment uniformity of the photoalignment method is high, and it is a non-contact alignment treatment method, so it has no damage Film, can reduce dust or static electricity and other causes of poor display of liquid crystal display elements and so on.

As such a liquid crystal alignment film using the photo-alignment method, for example, it is described in Patent Documents 1 to 6 that using diaminoazobenzene and the like as raw materials and applying photoisomerization technology to obtain anchoring energy Large photo-alignment film with good liquid crystal alignment. [Prior art literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2010-197999 [Patent Document 2] International Publication No. 2013/157463 [Patent Document 3] Japanese Patent Laid-Open No. 2005-275364 [Patent Document 4] Japanese Patent Laid-Open No. 2007-248637 [Patent Document 5] Japanese Patent Laid-Open No. 2009-069493 [Patent Document 6] International Publication No. 2015/016118

[Problem to be Solved by the Invention]

In recent years, liquid crystal display elements have been used in monitors for personal computers, liquid crystal televisions, mobile phones, display parts of smartphones, and medical monitors. Further, more excellent display quality is required, and contrast ratio is cited as an important characteristic affecting display quality. In addition, in a liquid crystal display element using a liquid crystal alignment film using a photo-alignment method, in order to improve the manufacturing efficiency of a liquid crystal display element, it is required to use a liquid crystal alignment film that can be aligned even in a short photo-alignment treatment time, that is, with a low exposure energy. During processing, good contrast can also be exhibited.

Therefore, the present inventors intend to provide a liquid crystal alignment film capable of forming a liquid crystal display element with good contrast and excellent display quality even when the exposure energy of the photo-alignment treatment is lower than before, and to provide a liquid crystal alignment film that can form A liquid crystal alignment agent for photo-alignment of such a liquid crystal alignment film has been intensively studied. [Means to solve the problem]

As a result of diligent research to solve the above problems, the present inventors have found that an alignment film having high liquid crystal alignment can be obtained by using a compound represented by formula (1-1) or formula (1-2), And by using the alignment film, it is possible to form a liquid crystal display element having good contrast and excellent display quality, and completed the present invention.

[2] 根據[1]所述的光配向用液晶配向劑，其中，所述光反應為光異構化、光弗裡斯重排、光分解及光二聚化中的至少一種。 [3] 根據[1]或[2]所述的光配向用液晶配向劑，其中，所述具有光反應性結構的化合物為式（2）所表示的化合物的至少一種。

式（2）中，X為碳數1～12的伸烷基，在所述伸烷基的碳數為2以上時，所述伸烷基的-(CH ₂) ₂-的不相鄰的一個以上可經-O-或-NH-取代， R ^a及R ^b分別獨立地為氫原子、甲基、甲氧基、三氟甲基、氟原子、甲氧基羰基、或者式（P1-1）或式（P1-2）所表示的一價基， R ^c分別獨立地為氫原子、甲基、甲氧基、三氟甲基、氟原子、或者式（P1-1）或式（P1-2）所表示的一價基，j為0或1，a～c分別獨立地為0～2的整數，

式（P1-1）及式（P1-2）中，R ^6a、R ^7a及R ^8a分別獨立地表示氫原子、經取代或未經取代的烷基、經取代或未經取代的烷醯基、或者經取代或未經取代的烷氧基羰基，R ^6a、R ^7a及R ^8a可相互相同，也可不同，*表示在式（2）中的苯環上的鍵結位置， 式（2）中，鍵結位置未固定於構成環的任一個碳原子上的基表示在所述環上的鍵結位置為任意。 [4] 根據[3]所述的光配向用液晶配向劑，其中，所述式（2）所表示的化合物為式（2-1）至式（2-3）的任一個。

式（2-1）中，R ^1a及R ^1c分別獨立地表示氫原子或者式（P1-1）或式（P1-2）所表示的一價基， 式（2-2）中，R ^2a及R ^2b分別獨立地表示氫原子或者式（P1-1）或式（P1-2）所表示的一價基，R ^2c分別獨立地為氫原子、甲基、甲氧基、三氟甲基、氟原子，X ₁為碳數1～12的伸烷基，在所述伸烷基的碳數為2以上時，所述伸烷基的-(CH ₂) ₂-的不相鄰的一個以上可經-O-或-NH-取代，k為0～2的整數， 式（2-3）中，R ^3a分別獨立地表示氫原子或者式（P1-1）或式（P1-2）所表示的一價基，R ⁴及R ⁵分別獨立地為氫原子或氟原子，R ⁴及R ⁵不會同時成為氫原子，R ^3c分別獨立地為氫原子、甲基、甲氧基、三氟甲基、氟原子，X ₁為碳數1～12的伸烷基，在所述伸烷基的碳數為2以上時，所述伸烷基的-(CH ₂) ₂-的不相鄰的一個以上可經-O-或-NH-取代，m為0～2的整數，

式（P1-1）及式（P1-2）中，R ^6a、R ^7a及R ^8a分別獨立地表示氫原子、經取代或未經取代的烷基、經取代或未經取代的烷醯基、或者經取代或未經取代的烷氧基羰基，R ^6a、R ^7a及R ^8a可相互相同，也可不同，*表示在式（2-1）、式（2-2）及式（2-3）中的苯環上的鍵結位置， 式（2-1）、式（2-2）及式（2-3）中，鍵結位置未固定於構成環的任一個碳原子上的基表示在所述環上的鍵結位置為任意。 [5] 根據[1]或[2]所述的光配向用液晶配向劑，其中，所述具有光反應性結構的化合物為式（3）所表示的化合物的至少一種。

式（3）中，R ¹及R ²分別獨立地表示氫原子、鹵素原子、碳數1至6的烷基、碳數1至6的鹵代烷基或碳數1至6的烷氧基，R ¹與R ²可成為一體而形成可經取代的亞甲基，X分別獨立地表示鹵素原子、碳數1至6的烷基、碳數1至6的鹵代烷基或碳數1至6的烷氧基，n獨立地表示0至4的整數。 [6] 根據[1]至[5]中任一項所述的光配向用液晶配向劑，還包含添加劑。 [7] 根據[6]所述的光配向用液晶配向劑，其中，所述添加劑為選自由噁唑啉化合物及環氧化合物所組成的群組中的至少一種。 [8] 一種液晶配向膜，由根據[1]至[7]中任一項所述的光配向用液晶配向劑形成。 [9] 一種液晶元件，具有根據[8]所述的液晶配向膜。 [10] 一種液晶配向膜的製造方法，包括：將根據[1]至[7]中任一項所述的光配向用液晶配向劑塗布於基板的步驟；以及對其塗膜照射偏光紫外線的步驟。 [發明的效果] The present invention includes the following structures. [1] A liquid crystal alignment agent for photo-alignment, comprising at least one polymer and a solvent, and in the liquid crystal alignment agent for photo-alignment, at least one of the polymers is made by reacting tetracarboxylic dianhydrides and diamines The resulting polymer comprises formula (1-1) or formula ( 1-2) A compound having a photoreactive structure that imparts liquid crystal alignment to an alignment film by at least one of the compounds shown in 1-2) reacting with light.

[2] The liquid crystal alignment agent for photo-alignment according to [1], wherein the photo-reaction is at least one of photo-isomerization, photo-Fries rearrangement, photo-decomposition and photo-dimerization. [3] The liquid crystal alignment agent for photo-alignment according to [1] or [2], wherein the compound having a photoreactive structure is at least one compound represented by formula (2).

In formula (2), X is an alkylene group with 1 to 12 carbons, and when the carbon number of the alkylene group is 2 or more, the non-adjacent -(CH ₂ ) ₂ - of the alkylene group More than one may be substituted by -O- or -NH-, R ^a and R ^b are each independently a hydrogen atom, methyl, methoxy, trifluoromethyl, fluorine atom, methoxycarbonyl, or the formula (P1- 1) or a monovalent group represented by formula (P1-2), R ^c are independently hydrogen atom, methyl, methoxy, trifluoromethyl, fluorine atom, or formula (P1-1) or formula ( In the monovalent group represented by P1-2), j is 0 or 1, and a to c are each independently an integer of 0 to 2,

In formula (P1-1) and formula (P1-2), R ^6a , R ^7a and R ^8a independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group , or a substituted or unsubstituted alkoxycarbonyl group, R ^6a , R ^7a and R ^8a may be the same as or different from each other, * represents the bonding position on the benzene ring in formula (2), formula (2 ), the group whose bonding position is not fixed to any carbon atom constituting the ring means that the bonding position on the ring is arbitrary. [4] The liquid crystal alignment agent for photo-alignment according to [3], wherein the compound represented by the formula (2) is any one of the formula (2-1) to the formula (2-3).

In formula (2-1), R ^1a and R ^1c independently represent a hydrogen atom or a monovalent group represented by formula (P1-1) or formula (P1-2), in formula (2-2), R ^2a and R ^2b each independently represent a hydrogen atom or a monovalent group represented by formula (P1-1) or formula (P1-2), and R ^2c each independently represent a hydrogen atom, methyl, methoxy, or trifluoromethyl , a fluorine atom, X ₁ is an alkylene group with 1 to 12 carbon atoms, and when the carbon number of the alkylene group is 2 or more, one of the non-adjacent -(CH ₂ ) ₂ - of the alkylene group The above can be substituted by -O- or -NH-, k is an integer from 0 to 2, in formula (2-3), R ^3a each independently represent a hydrogen atom or formula (P1-1) or formula (P1-2) In the monovalent group represented, R ⁴ and R ⁵ are independently hydrogen atoms or fluorine atoms, R ⁴ and R ⁵ cannot become hydrogen atoms at the same time, and R ^3c are independently hydrogen atoms, methyl groups, methoxy groups, Trifluoromethyl, fluorine atom, X ₁ is an alkylene group with 1 to 12 carbons, and when the carbon number of the alkylene group is 2 or more, the -(CH ₂ ) ₂ - of the alkylene group is not One or more adjacent ones may be substituted by -O- or -NH-, m is an integer of 0-2,

In formula (P1-1) and formula (P1-2), R ^6a , R ^7a and R ^8a independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group , or a substituted or unsubstituted alkoxycarbonyl group, R ^6a , R ^7a and R ^8a may be the same as or different from each other, * is represented in formula (2-1), formula (2-2) and formula (2 -3) the bonding position on the benzene ring, in formula (2-1), formula (2-2) and formula (2-3), the bonding position is not fixed on any carbon atom constituting the ring The group means that the bonding position on the ring is arbitrary. [5] The liquid crystal alignment agent for photo-alignment according to [1] or [2], wherein the compound having a photoreactive structure is at least one compound represented by formula (3).

In formula (3), R ¹ and R ² independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbons, a haloalkyl group with 1 to 6 carbons or an alkoxy group with 1 to 6 carbons, R ¹ and ^R2 can be integrated to form a substituted methylene group, and X each independently represent a halogen atom, an alkyl group with 1 to 6 carbons, a haloalkyl group with 1 to 6 carbons, or an alkane with 1 to 6 carbons Oxygen group, n independently represent the integer of 0-4. [6] The liquid crystal alignment agent for photo-alignment according to any one of [1] to [5], further comprising an additive. [7] The liquid crystal alignment agent for photo-alignment according to [6], wherein the additive is at least one selected from the group consisting of oxazoline compounds and epoxy compounds. [8] A liquid crystal alignment film formed from the liquid crystal alignment agent for photo-alignment according to any one of [1] to [7]. [9] A liquid crystal element having the liquid crystal alignment film according to [8]. [10] A method of manufacturing a liquid crystal alignment film, comprising: a step of coating the liquid crystal alignment agent for photo-alignment according to any one of [1] to [7] on a substrate; and irradiating the coating film with polarized ultraviolet rays step. [Effect of the invention]

By using the liquid crystal alignment agent for photo-alignment of this invention, even when the exposure energy of a photo-alignment process is small, the liquid crystal alignment film which has high liquid crystal alignment property can be obtained. Moreover, by using the liquid crystal alignment film, it is possible to efficiently realize the manufacture of a liquid crystal display element with good contrast and excellent display quality.

Hereinafter, the present invention will be described in detail. The description of the constituent requirements described below may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. The "liquid crystal alignment agent" in the present invention is a liquid crystal alignment agent that can impart anisotropy by irradiating polarized ultraviolet rays when the film is formed on a substrate. In this specification, it may also be simply referred to as "liquid crystal alignment agent" sometimes , It is also sometimes called "liquid crystal alignment agent for photo-alignment". In addition, in this invention, a "tetracarboxylic dianhydride" means a tetracarboxylic dianhydride, a tetracarboxylic diester, or a tetracarboxylic-acid diester dihalide. In addition, in the present invention, diamine and dihydrazide may also be referred to as "diamines".

<The liquid crystal alignment agent for photo-alignment of the present invention> The liquid crystal alignment agent for photo-alignment of the present invention is characterized in that it contains at least A polymer, as a raw material of the polymer, comprising at least one of the compounds represented by formula (1-1) or formula (1-2) and having a photoreactive compound that imparts liquid crystal alignment to an alignment film by photoreaction Compounds with sexual structure. In the present invention, the polyamic acid derivatives refer to polyimides, partial polyimides, polyamic acid esters, polyamic acid-polyamide copolymers, and polyamideimides. Such polymers are sometimes referred to as polymers of the present invention.

<Compound represented by formula (1-1) or formula (1-2)> Formula (1-1) or formula (1-2) represented by the polymer contained in the liquid crystal alignment agent of the present invention compounds are described.

The total amount of tetracarboxylic dianhydrides used in the polymer contained in the liquid crystal alignment agent of the present invention can be a compound represented by formula (1-1) or formula (1-2), and the formula ( A compound represented by 1-1) and a compound represented by formula (1-2). Furthermore, other tetracarboxylic dianhydrides described below may also be used in combination, and in that case, the content of other tetracarboxylic dianhydrides is preferably 5 mol with respect to the total amount of tetracarboxylic dianhydrides in the monomer % or more, more preferably 20 mol % to 80 mol %.

In the molecular structure of the compound represented by the formula (1-1) or the compound represented by the formula (1-2), two dicarboxylic acid anhydride skeletons exist in the exo form (exo) with respect to the norbornane rings respectively bonded. s position. With respect to the compound represented by formula (1-1) or the compound represented by formula (1-2), there are one or two dicarboxylic acid anhydride skeletons present in the endotype (endo) relative to the bonded norbornane ring. ) position of the stereoisomer. In the polymer using the compound represented by the formula (1-1) and the polymer using the compound represented by the formula (1-2), compared with the case of using these stereoisomers, by the alignment treatment, the The anisotropy expressed in the liquid crystal alignment film is larger, and it is more excellent from a viewpoint of liquid crystal alignment.

＜Compounds with a photoreactive structure＞ The compound which has a photoreactive structure used as a raw material of the polymer contained in the liquid crystal aligning agent of this invention is demonstrated. In the present specification, the term "photoreactive structure" refers to a structure that induces a photoreaction by irradiating light including a specific wavelength band corresponding to the photoreactive structure. Examples of photoreactions include photoisomerization, photo-Friesian rearrangement, photolysis, and photodimerization. By using a compound having a photoreactive structure as a raw material, a photoreactive structure can be incorporated into the polymer. In addition, regarding the compounds listed as compounds having a photoreactive structure in this specification, when the process of forming an alignment film from a liquid crystal alignment agent is not irradiated with light containing a specific wavelength band corresponding to the photoreactive structure In some cases, it can also be used as a raw material as a compound not having a photoreactive structure.

When the coating film containing the liquid crystal alignment agent for photo-alignment of the present invention is irradiated with polarized light of a predetermined wavelength in the process of forming the liquid crystal alignment film, the photoreactive structure of the polymer chain approximately parallel to the polarization direction causes a photoreaction Components facing a specific direction (direction approximately perpendicular to the polarization direction of irradiated light) among the polymer chains dominate, thereby obtaining an anisotropic coating film. A state in which components facing a specific direction in the polymer chains dominate is expressed as polymer chains being aligned. When the photo-alignment film formed by firing the anisotropic coating film is used in a liquid crystal display element, the result of the interaction between the surface of the film after alignment and the liquid crystal molecules is that the liquid crystal molecules are aligned in a certain direction. (a direction substantially perpendicular to the polarization direction of the irradiated light) by aligning the major axes.

式（A）中，*為鍵結鍵，鍵結鍵相對於苯環的鍵結位置分別獨立地為任意，苯環的能夠進行取代的氫原子可經取代基取代。 <The structure which causes a photoisomerization reaction> As an example of the structure which causes a photoisomerization reaction in this invention, the structure which has an azobenzene skeleton is mentioned. In this specification, the structure which has an azobenzene skeleton means the structure represented by following formula (A).

In the formula (A), * is a bonding bond, and the bonding positions of the bonding bonds with respect to the benzene ring are each independently arbitrary, and the substitutable hydrogen atom of the benzene ring may be substituted with a substituent.

式（2）中，X為碳數1～12的伸烷基，在所述伸烷基的碳數為2以上時，所述伸烷基的-(CH ₂) ₂-的不相鄰的一個以上可經-O-或-NH-取代， R ^a及R ^b分別獨立地為氫原子、甲基、甲氧基、三氟甲基、氟原子、甲氧基羰基、或者式（P1-1）或式（P1-2）所表示的一價基，R ^c分別獨立地為氫原子、甲基、甲氧基、三氟甲基、氟原子、或者式（P1-1）或式（P1-2）所表示的一價基，j為0或1，a～c分別獨立地為0～2的整數，

式（P1-1）及式（P1-2）中，R ^6a、R ^7a及R ^8a分別獨立地表示氫原子、經取代或未經取代的烷基、經取代或未經取代的烷醯基、或者經取代或未經取代的烷氧基羰基，R ^6a、R ^7a及R ^8a可相互相同，也可不同，*表示在式（2）中的苯環上的鍵結位置， 式（2）中，鍵結位置未固定於構成環的任一個碳原子上的基表示在所述環上的鍵結位置為任意。 Specifically, the compound having an azobenzene structure used in the polymer contained in the liquid crystal alignment agent for photo-alignment of the present invention is a compound represented by formula (2).

In formula (2), X is an alkylene group with 1 to 12 carbons, and when the carbon number of the alkylene group is 2 or more, the non-adjacent -(CH ₂ ) ₂ - of the alkylene group More than one may be substituted by -O- or -NH-, R ^a and R ^b are each independently a hydrogen atom, methyl, methoxy, trifluoromethyl, fluorine atom, methoxycarbonyl, or the formula (P1- 1) or a monovalent group represented by formula (P1-2), R ^c are independently hydrogen atom, methyl, methoxy, trifluoromethyl, fluorine atom, or formula (P1-1) or formula ( In the monovalent group represented by P1-2), j is 0 or 1, and a to c are each independently an integer of 0 to 2,

In formula (P1-1) and formula (P1-2), R ^6a , R ^7a and R ^8a independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group , or a substituted or unsubstituted alkoxycarbonyl group, R ^6a , R ^7a and R ^8a may be the same as or different from each other, * represents the bonding position on the benzene ring in formula (2), formula (2 ), the group whose bonding position is not fixed to any carbon atom constituting the ring means that the bonding position on the ring is arbitrary.

式（2-1）中，R ^1a及R ^1c分別獨立地表示氫原子、式（P1-1）或式（P1-2）所表示的一價基， 式（2-2）中，R ^2a及R ^2b分別獨立地表示氫原子、式（P1-1）或式（P1-2）所表示的一價基，R ^2c分別獨立地為氫原子、甲基、甲氧基、三氟甲基、氟原子，X ₁為碳數1～12的伸烷基，在所述伸烷基的碳數為2以上時，所述伸烷基的-(CH ₂) ₂-的不相鄰的一個以上可經-O-或-NH-取代，k為0～2的整數， 式（2-3）中，R ^3a分別獨立地表示氫原子、式（P1-1）或式（P1-2）所表示的一價基，R ⁴、R ⁵分別獨立地為氫原子或-F，R ⁴及R ⁵不會同時成為氫原子，R ^3c分別獨立地為氫原子、甲基、甲氧基、三氟甲基、氟原子，X ₁為碳數1～12的伸烷基，在所述伸烷基的碳數為2以上時，所述伸烷基的-(CH ₂) ₂-的不相鄰的一個以上可經-O-或-NH-取代，m為0～2的整數，

式（P1-1）及式（P1-2）中，R ^6a、R ^7a及R ^8a分別獨立地表示氫原子、經取代或未經取代的烷基、經取代或未經取代的烷醯基、或者經取代或未經取代的烷氧基羰基，R ^6a、R ^7a及R ^8a可相互相同，也可不同，*表示在式（2-1）、式（2-2）及式（2-3）中的苯環上的鍵結位置， 式（2-1）、式（2-2）及式（2-3）中，鍵結位置未固定於構成環的任一個碳原子上的基表示在所述環上的鍵結位置為任意。 Specifically, the compound represented by the formula (2) is a compound represented by the following formulas (2-1) to (2-3).

In formula (2-1), R ^1a and R ^1c independently represent a hydrogen atom, a monovalent group represented by formula (P1-1) or formula (P1-2), and in formula (2-2), R ^2a and R ^2b each independently represent a hydrogen atom, a monovalent group represented by formula (P1-1) or formula (P1-2), and R ^2c each independently represent a hydrogen atom, methyl, methoxy, or trifluoromethyl , a fluorine atom, X ₁ is an alkylene group with 1 to 12 carbon atoms, and when the carbon number of the alkylene group is 2 or more, one of the non-adjacent -(CH ₂ ) ₂ - of the alkylene group The above can be substituted by -O- or -NH-, k is an integer from 0 to 2, in formula (2-3), R ^3a independently represent a hydrogen atom, formula (P1-1) or formula (P1-2) In the monovalent group represented, R ⁴ and R ⁵ are each independently a hydrogen atom or -F, R ⁴ and R ⁵ will not become a hydrogen atom at the same time, and R ^3c is independently a hydrogen atom, methyl, methoxy, Trifluoromethyl, fluorine atom, X ₁ is an alkylene group with 1 to 12 carbons, and when the carbon number of the alkylene group is 2 or more, the -(CH ₂ ) ₂ - of the alkylene group is not One or more adjacent ones may be substituted by -O- or -NH-, m is an integer of 0-2,

In formula (P1-1) and formula (P1-2), R ^6a , R ^7a and R ^8a independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group , or a substituted or unsubstituted alkoxycarbonyl group, R ^6a , R ^7a and R ^8a may be the same as or different from each other, * is represented in formula (2-1), formula (2-2) and formula (2 -3) the bonding position on the benzene ring, in formula (2-1), formula (2-2) and formula (2-3), the bonding position is not fixed on any carbon atom constituting the ring The group means that the bonding position on the ring is arbitrary.

式（2-1-2）中，R ^6a為碳數1～4的烷基。 Specific examples of the compound represented by formula (2-1) include the following compounds.

In formula (2-1-2), R ^6a is an alkyl group having 1 to 4 carbon atoms.

式（2-2-1）～式（2-2-6）中，R ^6a為碳數1～4的烷基，l為1～10的整數，m為1～11的整數。 Specific examples of the compound represented by formula (2-2) include the following compounds.

In formulas (2-2-1) to (2-2-6), R ^6a is an alkyl group having 1 to 4 carbon atoms, l is an integer of 1 to 10, and m is an integer of 1 to 11.

式（2-3-1）及式（2-3-2）中，l為1～10的整數。 Specific examples of the compound represented by formula (2-3) include the following compounds.

In formula (2-3-1) and formula (2-3-2), l is an integer of 1-10.

In the case of emphasizing the transparency of the formed liquid crystal alignment film, it is preferable to use formula (2-1-2), formula (2-1-3), formula (2-2-3), formula (2 -2-4), any one or more of the compounds in the group consisting of formula (2-2-5) and formula (2-2-6), more preferably formula (2-1-2) or formula ( 2-1-3), particularly preferably the compound in which R ^6a is ethyl in formula (2-1-2).

When it is important to obtain a liquid crystal alignment film (that is, a liquid crystal alignment agent with high sensitivity) that can form an element with good afterimage characteristics even if the energy is low during the alignment treatment, it is preferable to use the liquid crystal alignment agent selected from the formula (2-1 -2), formula (2-1-3), formula (2-2-3), formula (2-2-4), formula (2-2-5), formula (2-2-6), formula Any one or more of the compounds in the group consisting of (2-3-1) and formula (2-3-2), more preferably formula (2-1-2), formula (2-3-1) or Formula (2-3-2), more preferably a compound in which R ^6a in formula (2-1-2) is an ethyl group or a compound represented by l=2 to 6 in formula (2-3-1).

When it is important to obtain a liquid crystal display element that can maintain a high voltage holding ratio (that is, VHR (Voltage Holding Ratio) is excellent in reliability) even if it is used for a long time, it is preferable to use a liquid crystal display element selected from the formula (2-1-2) and the formula (2-1-3), formula (2-2-1), formula (2-2-2), formula (2-2-3), formula (2-2-4), formula (2-2- 5) and any one or more of the compounds in the group consisting of formula (2-2-6), more preferably formula (2-1-2), formula (2-1-3) or formula (2-2 -1) Compounds represented by l=2 to 6, more preferably compounds in which R ^6a is ethyl in formula (2-1-2) or compounds represented by l=2 to 6 in formula (2-2-1) compound of.

When it is important to obtain a liquid crystal display element with a higher contrast ratio, it is preferable to use one selected from the group consisting of formula (2-1-1), formula (2-2-1) and formula (2-2-2). Any one or more of the compounds in Formula (2-1-1) or the compound represented by l=2-6 in Formula (2-2-1) is more preferable. In said case, relative to the total amount of diamine in the monomer, the diamine in the polymer is selected from formula (2-1-1), formula (2-2-1) and formula (2-2-2) The total content of the compounds in the group formed is preferably 20 mol % to 100 mol %, more preferably 40 mol % to 100 mol %.

式（B）中，*為鍵結鍵，鍵結鍵相對於苯環的鍵結位置為任意，苯環的能夠進行取代的氫原子可經取代基取代。作為本發明的液晶配向劑中所含的聚合物中所使用的、具有引起光弗裡斯重排反應的結構的化合物的優選例，可列舉下述式（3）。除此以外，作為具有引起光弗裡斯重排反應的結構的化合物，可列舉式（AN-4-32）～式（AN-4-36）、式（DI-5-32）、式（DI-5-33）、式（DI-5-35）及式（DI-6-8）～式（DI-6-10）所表示的化合物。

式（3）中，R ¹及R ²分別獨立地表示氫原子、鹵素原子、碳數1至6的烷基、碳數1至6的鹵代烷基或碳數1至6的烷氧基。R ¹與R ²可成為一體而形成可經取代的亞甲基。X分別獨立地表示鹵素原子、碳數1至6的烷基、碳數1至6的鹵代烷基或碳數1至6的烷氧基，n表示0至4的整數。式（DI-5-35）中的m表示0至12的整數。 <The compound which has the structure which induces photo-Fries rearrangement reaction> As an example of the structure which causes photo-Fries rearrangement reaction in this invention, the structure which has a phenyl ester skeleton is mentioned. The structure which has a phenyl ester skeleton in this specification means the structure represented by following formula (B).

In the formula (B), * is a bonding bond, the bonding position of the bonding bond with respect to the benzene ring is arbitrary, and the substitutable hydrogen atom of the benzene ring may be substituted by a substituent. The following formula (3) is mentioned as a preferable example of the compound which has the structure which causes photo-Fries rearrangement reaction used for the polymer contained in the liquid crystal aligning agent of this invention. In addition, as a compound having a structure causing a photo-Friesian rearrangement reaction, formula (AN-4-32) to formula (AN-4-36), formula (DI-5-32), formula (DI -5-33), formula (DI-5-35) and the compounds represented by formula (DI-6-8) to formula (DI-6-10).

In formula (3), R ¹ and R ² independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbons, a haloalkyl group having 1 to 6 carbons, or an alkoxy group having 1 to 6 carbons. R ¹ and R ² may be united to form an optionally substituted methylene group. X each independently represents a halogen atom, an alkyl group having 1 to 6 carbons, a haloalkyl group having 1 to 6 carbons, or an alkoxy group having 1 to 6 carbons, and n represents an integer of 0 to 4. m in the formula (DI-5-35) represents an integer of 0 to 12.

Among these compounds, from the viewpoint of producing a high-contrast liquid crystal display device, it is preferable to use the compound represented by formula (3), and it is more preferable to use the amino group on each benzene ring in formula (3) relative to the ester group. Para compound.

The total content of the compounds represented by formula (3) is preferably 40 mol % to 100 mol %, more preferably 70 mol % to 100 mol %, based on the total amount of diamines in the monomer.

Specific examples of the compound represented by formula (3) include compounds represented by the following formula (3-1) to formula (3-6).

式（C）中，*1、*1'、*2及*2'為鍵結鍵，*1及*1'組及*2及*2'組中的任一組或兩組可與同一O鍵結。即，可形成酸酐-CO-O-CO-。R ^b1、R ^b2、R ^b3及R ^b4分別獨立地為一價有機基。 <The structure which causes a photolysis reaction> As an example of the structure which causes a photolysis reaction in this invention, the structure which has a cyclobutane tetracarboxylic-acid skeleton is mentioned. In this specification, the structure which has a cyclobutane tetracarboxylic-acid skeleton means the structure represented by following formula (C).

In formula (C), *1, *1', *2 and *2' are bonding bonds, any one or two groups of *1 and *1' group and *2 and *2' group can be combined with the same O bond. That is, acid anhydride -CO-O-CO- can be formed. R ^b1 , R ^b2 , R ^b3 and R ^b4 are each independently a monovalent organic group.

式（PA-3）～式（PA-6）中，R ¹¹獨立地為碳數1～5的烷基。 Preferable examples of compounds having a structure that causes a photodecomposition reaction used in the polymer contained in the liquid crystal alignment agent of the present invention include the following formulas (PA-1) to (PA-6) compound of.

In formula (PA-3) to formula (PA-6), R ¹¹ is independently an alkyl group having 1 to 5 carbon atoms.

式（D）中，*為鍵結鍵，鍵結鍵相對於苯環的鍵結位置為任意，苯環的能夠進行取代的氫原子可經取代基取代。 <The structure which causes a photodimerization reaction> As an example of the structure which causes a photodimerization reaction in this invention, the structure which has a cinnamic-acid skeleton is mentioned. In this specification, the structure which has a cinnamic-acid skeleton means the structure represented by following formula (D).

In the formula (D), * is a bonding bond, the bonding position of the bonding bond with respect to the benzene ring is arbitrary, and the substitutable hydrogen atom of the benzene ring may be substituted by a substituent.

式（PDI-12）中，R ¹²為碳數1～10的烷基或烷氧基，烷基或烷氧基的至少一個氫原子可被氟原子取代。 Preferable examples of compounds having a structure that causes a photodimerization reaction used in the polymer contained in the liquid crystal alignment agent of the present invention include the following formulas (PDI-9) to (PDI-13) indicated compound.

In the formula (PDI-12), R ¹² is an alkyl or alkoxy group having 1 to 10 carbon atoms, and at least one hydrogen atom of the alkyl or alkoxy group may be replaced by a fluorine atom.

＜Types of polymers＞ Hereinafter, polyamic acid and polyamic acid derivatives will be described in detail.

Here, polyamic acid is a polymer synthesized by the polymerization reaction of diamines represented by formula (DI) and tetracarboxylic dianhydride represented by formula (AN), and has a polyamide represented by formula (PAA). constituent unit. Liquid crystal alignment agent containing polyamic acid When heating and sintering in the step of forming the liquid crystal alignment film, the polyamic acid is imidized to form a polyamide having a structural unit represented by the formula (PI) Amine liquid crystal alignment film.

In formula (AN), formula (PAA) and formula (PI), X ¹ is a tetravalent organic group. In formula (DI), formula (PAA) and formula (PI), X ² is a divalent organic group. For the preferred range and specific examples of the tetravalent organic group in ^X1 , refer to formula (1) or the structure corresponding to the tetracarboxylic dianhydride described in the column of other tetracarboxylic dianhydrides below. For the preferred range and specific examples of the divalent organic group in X ² , refer to the description related to the structure corresponding to the formula (2) or the diamine or dihydrazide described in the column of other diamines below.

式（PAE）中，X ¹為四價有機基，X ²為二價有機基，Y獨立地為烷基。關於X ¹、X ²的優選範圍與具體例，可參照與式（PAA）中的X ¹、X ²相關的記載。Y中，優選為碳數1～6的直鏈或分支鏈的烷基，更優選為甲基、乙基、丙基、異丙基、丁基、異丁基或第三丁基。 The polyamic acid derivative is a compound whose characteristics are changed by substituting a part of the polyamic acid with another atom or atomic group, and is particularly preferably a polyamic acid having improved solubility in a solvent used in a liquid crystal alignment agent. derivative. Specific examples of such polyamic acid derivatives include: 1) polyimides in which all amino groups and carboxyl groups of polyamic acid undergo a dehydration ring-closure reaction; 3) Polyamic acid ester obtained by converting the carboxyl group of polyamic acid into an ester, 4) Substituting a part of the acid dianhydride contained in the tetracarboxylic dianhydride compound with an organic di Carboxylic acid and the polyamide acid-polyamide copolymer obtained by reacting, and 5) the polyamide acid-polyamide copolymer obtained by subjecting part or all of the polyamide acid-polyamide copolymer to dehydration and ring-closure reaction imine. Among these derivatives, for example, polyimides having a structural unit represented by the formula (PI) can be cited, and polyimides having the following formula (PAE) can be cited as polyimides. Represents the constituent unit of polyamide ester.

In the formula (PAE), X ¹ is a tetravalent organic group, X ² is a divalent organic group, and Y is independently an alkyl group. For preferred ranges and specific examples of X ¹ and X ² , reference can be made to the description related to X ¹ and X ² in formula (PAA). Among Y, it is preferably a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group or t-butyl group.

Polyamic acid can be obtained as a reaction product obtained by the polymerization reaction of tetracarboxylic dianhydrides and diamines. For the description, preferred range, and specific examples of tetracarboxylic dianhydrides, refer to the description in the column of tetracarboxylic dianhydrides below. For the description, preferred range, and specific examples of diamines, refer to the description in the column of the following diamines.

The tetracarboxylic dianhydrides and diamines used in the synthesis of polyamic acid may be one kind or two or more kinds. By using the compound represented by the formula (1-1) or the formula (1-2) as at least one of the tetracarboxylic dianhydrides, and then using a photoreactive compound that imparts liquid crystal alignment to the alignment film by photoreaction The compound of sexual structure can obtain the polyamic acid of the present invention.

In the case where the polyamic acid of the present invention is polyimide which is a derivative of polyamic acid, by mixing the obtained polyamic acid solution with acetic anhydride or propionic anhydride as a dehydrating agent, , trifluoroacetic anhydride and other acid anhydrides and tertiary amines such as triethylamine, pyridine and collidine as dehydration ring-closing catalysts can be imidized at a temperature of 20°C to 150°C to obtain polyimide. Alternatively, polyamic acid can be precipitated from the obtained polyamic acid solution using a large amount of poor solvent (alcohol-based solvents such as methanol, ethanol, and isopropanol, or glycol-based solvents), and the precipitated polyamic acid can be precipitated. Amino acid is subjected to imidization reaction at a temperature of 20°C to 150°C together with the dehydrating agent and the dehydration ring-closing catalyst in solvents such as toluene and xylene, thereby obtaining polyimide.

In the imidization reaction, the ratio of the dehydrating agent to the dehydration ring-closing catalyst is preferably 0.1-10 (molar ratio). It is preferable that the total usage-amount of a dehydrating agent and a dehydration ring-closing catalyst is 1.5 times mole - 10 times mole with respect to the sum total of the molar quantity of the tetracarboxylic dianhydride used for the synthesis|combination of the said polyamic acid. By adjusting the dehydrating agent, catalyst amount, reaction temperature and reaction time used in the imidization reaction, the degree of imidization can be controlled, thereby obtaining only a part of the imide of polyamic acid A part of polyimide formed by chemical reaction. The obtained polyimide may be separated from the solvent used in the reaction and redissolved in another solvent to be used as a liquid crystal alignment agent, or may be used as a liquid crystal alignment agent without being separated from the solvent.

Polyamic acid ester can be obtained by the following method: by the method of making polyamic acid and hydroxyl-containing compound, halide, epoxy group-containing compound etc. reaction and synthesized method, or by making tetracarboxylic acid A method for synthesizing tetracarboxylic acid diester derived from dianhydride or tetracarboxylic acid diester dichloride by reacting with diamines. Tetracarboxylic acid diesters derived from tetracarboxylic dianhydrides can be obtained by reacting tetracarboxylic dianhydrides with 2 equivalents of alcohol and opening rings, and tetracarboxylic acid diester dichlorides can be obtained by making tetracarboxylic acid diesters and 2 equivalents of chlorinating agent (for example, thionyl chloride, etc.) reaction to obtain. In addition, the polyamic acid ester may have only an amic acid ester structure, and may be a partial esterified product in which an amic acid structure and an amic acid ester structure coexist. By using the compound represented by the formula (1-1) or the formula (1-2) as at least one of the tetracarboxylic dianhydrides, and then using a photoreactive compound that imparts liquid crystal alignment to the alignment film by photoreaction The compound of sexual structure can obtain the polyamic acid ester of the present invention.

The polyamic acid or derivatives thereof of the present invention can be produced in the same manner as known polyamic acids or derivatives thereof used in the formation of polyimide membranes. It is preferable that the total input amount of tetracarboxylic dianhydrides shall be 0.9 mol - 1.1 mol with respect to 1 mol of total diamines.

The liquid crystal alignment agent of the present invention may contain only one of these polyamide acids, polyamide esters, and polyimides obtained by imidizing them, or may contain two or more thereof.

The molecular weight of the polyamic acid or derivatives thereof of the present invention is preferably 5,000 to 500,000, more preferably 5,000 to 50,000 in terms of polystyrene-equivalent weight average molecular weight (Mw). The molecular weight of polyamic acid or a derivative thereof can be determined by measurement by gel permeation chromatography (Gel Permeation Chromatography, GPC).

The presence of the polyamide acid or its derivatives of the present invention can be confirmed by the following methods: using infrared spectroscopy (Infrared spectroscopy, IR), nuclear magnetic resonance analysis (Nuclear Magnetic Resonance, NMR) to make the polyamide acid of the present invention The solid content obtained by precipitation of amine acid or its derivatives in a large amount of poor solvent was analyzed. In addition, the monomers used can be confirmed by the following methods: Gas Chromatography (Gas Chromatography, GC), High Performance Liquid Chromatography (High Performance Liquid Chromatography, HPLC) or Gas Chromatography-Mass Spectrometry (Gas Chromatography- Mass Spectrometry (GC-MS) analyzes the extract extracted from the decomposition products using an organic solvent after decomposing the polyamic acid or its derivatives using an aqueous solution of a strong base such as KOH or NaOH.

＜Other tetracarboxylic dianhydrides＞ Tetracarboxylic dianhydrides other than the compound represented by formula (1-1) or formula (1-2) used as the raw material of the polymer of the present invention can be selected from known tetracarboxylic dianhydrides without limitation. Class selection.

Hereinafter, examples of other tetracarboxylic dianhydrides are given. These tetracarboxylic dianhydrides can also be used as a raw material of a polymer by derivatizing them into tetracarboxylic-acid diester or tetracarboxylic-acid diester dichloride.

This kind of tetracarboxylic dianhydride can be an aromatic system (including heteroaromatic ring system) in which the dicarboxylic acid anhydride is directly bonded to the aromatic ring and an aliphatic system (including heteroaromatic ring system) in which the dicarboxylic anhydride is not directly bonded to the aromatic ring. The tetracarboxylic dianhydride in the group of any one of the ring system).

Examples of such tetracarboxylic dianhydrides include the following formulas (AN-1) to (AN-9), formula (AN-11), formula (AN-12), formula (AN-15), Compounds represented by formula (AN-10-1), formula (AN-10-2) and formula (AN-16-1) to formula (AN-16-15).

式（AN-1）中，G ¹¹為單鍵、碳數1～12的伸烷基、1,4-亞苯基或1,4-亞環己基。X ¹¹獨立地為單鍵或-CH ₂-。G ¹²獨立地為下述三價基的任一種。

在G ¹²為＞CH-時，＞CH-的氫原子可經甲基取代。在G ¹²為＞N-時，G ¹¹不為單鍵及-CH ₂-，X ¹¹不為單鍵。 R ¹¹獨立地為氫原子或甲基。 [Tetracarboxylic dianhydride represented by formula (AN-1)]

In the formula (AN-1), G ¹¹ is a single bond, an alkylene group having 1 to 12 carbon atoms, a 1,4-phenylene group or a 1,4-cyclohexylene group. X ¹¹ is independently a single bond or -CH ₂ -. G ¹² is independently any of the following trivalent groups.

When G ¹² is >CH-, the hydrogen atom of >CH- may be substituted with a methyl group. When G ¹² is >N-, G ¹¹ is not a single bond and -CH ₂ -, and X ¹¹ is not a single bond. R ¹¹ is independently a hydrogen atom or a methyl group.

式（AN-1-2）及式（AN-1-14）中，m分別獨立地為1～12的整數。 As an example of the tetracarboxylic dianhydride represented by a formula (AN-1), the compound represented by following formula (AN-1-1) - a formula (AN-1-15) is mentioned.

In Formula (AN-1-2) and Formula (AN-1-14), m is an integer of 1-12 each independently.

式（AN-2）中，R ⁶¹獨立地為氫原子、碳數1～5的烷基或苯基。 [Tetracarboxylic dianhydride represented by formula (AN-2)]

In formula (AN-2), R ⁶¹ is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-2), the compound represented by following formula (AN-2-1) - a formula (AN-2-3) is mentioned.

式（AN-3）中，環A ¹¹為環己烷環或苯環。 [Tetracarboxylic dianhydride represented by formula (AN-3)]

In formula (AN-3), ring A ¹¹ is a cyclohexane ring or a benzene ring.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-3), the compound represented by following formula (AN-3-1) and a formula (AN-3-2) is mentioned.

式（AN-4）中，G ¹³為單鍵、-(CH ₂) _m-、-O-、-S-、-C(CH ₃) ₂-、-SO ₂-、-CO-、-C(CF ₃) ₂-或下述式（G13-1）所表示的二價基，m為1～12的整數。環A ¹¹分別獨立地為環己烷環或苯環。G ¹³可鍵結於環A ¹¹的任意位置。

式（G13-1）中，G ^13a及G ^13b分別獨立地為單鍵、-O-、-CONH-或-NHCO-所表示的二價基。亞苯基優選為1,4-亞苯基或1,3-亞苯基。 [Tetracarboxylic dianhydride represented by formula (AN-4)]

In formula (AN-4), G ¹³ is a single bond, -(CH ₂ ) _m -, -O-, -S-, -C(CH ₃ ) ₂ -, -SO ₂ -, -CO-, -C (CF ₃ ) ₂ -or a divalent group represented by the following formula (G13-1), m is an integer of 1-12. Ring A ¹¹ is each independently a cyclohexane ring or a benzene ring. G ¹³ can be bonded to any position of ring A ¹¹ .

In formula (G13-1), G ^13a and G ^13b are each independently a divalent group represented by a single bond, -O-, -CONH- or -NHCO-. The phenylene is preferably 1,4-phenylene or 1,3-phenylene.

式（AN-4-17）中，m為1～12的整數。 As an example of the tetracarboxylic dianhydride represented by a formula (AN-4), the compound represented by following formula (AN-4-1) - a formula (AN-4-31) is mentioned.

In formula (AN-4-17), m is an integer of 1-12.

式（AN-5）中，R ¹¹獨立地為氫原子或甲基。兩個R ¹¹中的苯環上的R ¹¹鍵結於苯環的能夠進行取代的位置的任一者上。 [Tetracarboxylic dianhydride represented by formula (AN-5)]

In formula (AN-5), R ¹¹ is independently a hydrogen atom or a methyl group. R ¹¹ on the benzene ring among the two R ¹¹ is bonded to any one of positions that can be substituted on the benzene ring.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-5), the compound represented by following formula (AN-5-1) - a formula (AN-5-3) is mentioned.

式（AN-6）中，X ¹¹獨立地為單鍵或-CH ₂-。X ¹²為-CH ₂-、-CH ₂CH ₂-或-CH=CH-。n為1或2。在n為2時，兩個X ¹²可相互相同，也可不同。 [Tetracarboxylic dianhydride represented by formula (AN-6)]

In formula (AN-6), X ¹¹ is independently a single bond or -CH ₂ -. X ¹² is -CH ₂ -, -CH ₂ CH ₂ - or -CH=CH-. n is 1 or 2. When n is 2, the two X ¹² may be the same as or different from each other.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-6), the compound represented by following formula (AN-6-1) - a formula (AN-6-12) is mentioned.

式（AN-7）中，X ¹¹為單鍵或-CH ₂-。 [Tetracarboxylic dianhydride represented by formula (AN-7)]

In formula (AN-7), X ¹¹ is a single bond or -CH ₂ -.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-7), the compound represented by following formula (AN-7-1) and a formula (AN-7-2) is mentioned.

式（AN-8）中，X ¹¹為單鍵或-CH ₂-。R ¹²為氫原子、甲基、乙基或苯基。環A ¹²為環己烷環或環己烯環。 [Tetracarboxylic dianhydride represented by formula (AN-8)]

In formula (AN-8), X ¹¹ is a single bond or -CH ₂ -. R ¹² is a hydrogen atom, methyl, ethyl or phenyl. Ring ^A12 is a cyclohexane ring or a cyclohexene ring.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-8), the compound represented by following formula (AN-8-1) and a formula (AN-8-2) is mentioned.

式（AN-9）中，r分別獨立地為0或1。 [Tetracarboxylic dianhydride represented by formula (AN-9)]

In formula (AN-9), r is 0 or 1 each independently.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-9), the compound represented by following formula (AN-9-1) - a formula (AN-9-3) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-10-1) and formula (AN-10-2)]

式（AN-11）中，環A ¹¹獨立地為環己烷環或苯環。 [Tetracarboxylic dianhydride represented by formula (AN-11)]

In formula (AN-11), ring A ¹¹ is independently a cyclohexane ring or a benzene ring.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-11), the compound represented by following formula (AN-11-1) - a formula (AN-11-3) is mentioned.

式（AN-12）中，環A ¹¹分別獨立地為環己烷環或苯環。 [Tetracarboxylic dianhydride represented by formula (AN-12)]

In formula (AN-12), ring A ¹¹ is each independently a cyclohexane ring or a benzene ring.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-12), the compound represented by following formula (AN-12-1) - a formula (AN-12-3) is mentioned.

式（AN-15）中，w為1～10的整數。 [Tetracarboxylic dianhydride represented by formula (AN-15)]

In formula (AN-15), w is an integer of 1-10.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-15), the compound represented by following formula (AN-15-1) - a formula (AN-15-3) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-16-1) to formula (AN-16-15)] Examples of tetracarboxylic dianhydrides other than those described above include the following formula (AN-16-1) ~ Compounds represented by formula (AN-16-15).

Among the tetracarboxylic dianhydrides, suitable materials for improving the properties of the liquid crystal alignment film described later will be described. In the case of emphasizing the further improvement of liquid crystal alignment, it is more preferred to be represented by formula (AN-1-2), formula (AN-4-17), formula (AN-4-21) or formula (AN-4-29) In the compound represented, m=4-8 is preferable in formula (AN-1-2), and m=4-8 is preferable in formula (AN-4-17).

When emphasis is placed on improving the transmittance of the liquid crystal display element, formula (AN-1-1), formula (AN-1-2), formula (AN-2-1), formula (AN-3-1) are preferable , formula (AN-4-17), formula (AN-4-30), formula (AN-5-1), formula (AN-7-2), formula (AN-10-1), formula (AN- 16-3) or the compound represented by formula (AN-16-4), wherein, in formula (AN-1-2), preferably m=4 or 8, in formula (AN-4-17), preferably m=4-8, more preferably m=8.

When emphasis is placed on improving the VHR of the liquid crystal display element, formula (AN-1-1), formula (AN-1-2), formula (AN-3-1), formula (AN-4-17), Formula (AN-4-30), Formula (AN-7-2), Formula (AN-10-1), Formula (AN-16-3), Formula (AN-16-4) or Formula (AN-2 -1) In the compound represented by formula (AN-1-2), m=4 or 8 is preferred; in formula (AN-4-17), m=4 or 8 is preferred, and m=8 is more preferred .

As one of the methods for preventing burn marks, it is effective to increase the relaxation speed of residual charges (residual direct current (DC)) in the liquid crystal alignment film by reducing the volume resistance of the liquid crystal alignment film. In the case of emphasizing the above purpose, it is preferably formula (AN-1-13), formula (AN-3-2), formula (AN-4-21), formula (AN-4-29) or formula (AN -11-3) represented by the compound.

＜Other diamines＞ Diamines other than the compound represented by formula (2) or formula (3) used as a raw material of the polymer of the present invention can be selected from known diamines without limitation.

Diamines can be classified into two types according to their structures. That is, a diamine having a side chain group branched from the main chain when the skeleton connecting two amino groups is regarded as the main chain, and a diamine having no side chain group. In the following description, the diamine which has such a side chain group may be called a side chain type diamine. Moreover, the diamine which does not have such a side chain group may be called a non-side chain type diamine. The side chain group is a group having an effect of increasing the pretilt angle. By appropriately using non-side chain type diamine and side chain type diamine separately, it can correspond to each desired pretilt angle.

It is preferable to use side chain type diamine together to the extent that the characteristic of this invention is not impaired. Moreover, it is preferable to select and use side-chain type diamine and non-side-chain type diamine for the purpose of improving characteristics, such as the vertical alignment property with respect to a liquid crystal, VHR, and afterimage characteristics.

所述式（DI-1）中，G ²⁰為-CH ₂-或式（DI-1-a）所表示的基。在G ²⁰為-CH ₂-時，m個-CH ₂-的至少一個可被取代為-NH-或-O-，m個-CH ₂-的至少一個氫原子可經羥基或甲基取代。m為1～12的整數。在DI-1中的m為2以上時，多個G ²⁰可相互相同，也可不同。其中，在G ²⁰為式（DI-1-a）時，m為1。

式（DI-1-a）中，v分別獨立地為1～6的整數。 The known diamine which does not have a side chain is shown by following formula (DI-1) - a formula (DI-16).

In the formula (DI-1), G ²⁰ is -CH ₂ - or a group represented by the formula (DI-1-a). When G ²⁰ is -CH ₂ -, at least one of the m -CH ₂ -s may be substituted with -NH- or -O-, and at least one hydrogen atom of the m -CH ₂ -s may be substituted with a hydroxyl group or a methyl group. m is an integer of 1-12. When m in DI-1 is 2 or more, a plurality of G ²⁰ may be the same as or different from each other. However, m is 1 when G ²⁰ is the formula (DI-1-a).

In Formula (DI-1-a), v is an integer of 1-6 each independently.

In formula (DI-3), formula (DI-6) and formula (DI-7), G ²¹ is independently a single bond, -NH-, -NCH ₃ -, -O-, -S-, -SS- , -SO ₂ -, -CO-, -COO-, -CONCH ₃ -, -CONH-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -(CH ₂ ) _m -, - O-(CH ₂ ) _m -O-, -N(CH ₃ )-(CH ₂ ) _k -N(CH ₃ )-, -(OC ₂ H ₄ ) _m -O-, -O-CH ₂ -C (CF ₃ ) ₂ -CH ₂ -O-, -O-CO-(CH ₂ ) _m -CO-O-, -CO-O-(CH ₂ ) _m -O-CO-, -(CH ₂ ) _m -NH-(CH ₂ ) _m -, -CO-(CH ₂ ) _k -NH-(CH ₂ ) _k -, -(NH-(CH ₂ ) _m ) _k -NH-, -CO-C ₃ H ₆ -(NH-C ₃ H ₆ ) _n -CO- or -S-(CH ₂ ) _m -S-, m is independently an integer of 1-12, k is an integer of 1-5, and n is 1 or 2. In formula (DI-4), s is an integer of 0-2 independently.

In formula (DI-5), G ³³ is a single bond, -NH-, -NCH ₃ -, -O-, -S-, -SS-, -SO ₂ -, -CO-, -COO-, -CONCH ₃ -, -CONH-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -(CH ₂ ) _m -, -O-(CH ₂ ) _m -O-, -N(CH ₃ )-(CH ₂ ) _k -N(CH ₃ )-, -(OC ₂ H ₄ ) _m -O-, -O-CH ₂ -C(CF ₃ ) ₂ -CH ₂ -O-, -O-CO -(CH ₂ ) _m -CO-O-, -CO-O-(CH ₂ ) _m -O-CO-, -(CH ₂ ) _m -NH-(CH ₂ ) _m -, -CO-(CH ₂ ) _k -NH-(CH ₂ ) _k -, -(NH-(CH ₂ ) _m ) _k -NH-, -CO-C ₃ H ₆ -(NH-C ₃ H ₆ ) _n -CO- or -S -(CH ₂ ) _m -S-, -N(Boc)-(CH ₂ ) _e -N(Boc)-, -NH-(CH ₂ ) _e -N(Boc)-, -N(Boc)-( CH ₂ ) _e -, -(CH ₂ ) _m -N(Boc)-CONH-(CH ₂ ) _m -, -(CH ₂ ) _m -N(Boc)-(CH ₂ ) _m -, or the following formula (DI-5-a) or the group represented by the following formula (DI-5-b), m is independently an integer of 1 to 12, k is an integer of 1 to 5, e is an integer of 2 to 10, n is 1 or 2. Boc is tertiary butoxycarbonyl.

In formula (DI-6) and formula (DI-7), G ²² is independently a single bond, -O-, -S-, -CO-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ - or an alkylene group having 1 to 10 carbon atoms.

At least one hydrogen atom of the cyclohexane ring and benzene ring in the formula (DI-2) ~ formula (DI-7) can be replaced by a fluorine atom, a chlorine atom, an alkylene group with 1 to 3 carbons, a methoxy group, a hydroxyl group , trifluoromethyl, carboxyl, carbamoyl, phenylamino, phenyl or benzyl, in addition, in formula (DI-4), at least one hydrogen atom of the cyclohexane ring and the benzene ring can be One substitution selected from the group represented by any one of the following formula (DI-4-a) to formula (DI-4-i), in formula (DI-5), G ³³ is a single When bonding, at least one hydrogen atom of the cyclohexane ring and the benzene ring may be substituted by NHBoc or N(Boc) ₂ .

式（DI-4-a）及式（DI-4-b）中，R ²⁰獨立地為氫原子或甲基。式（DI-4-f）及式（DI-4-g）中，m分別獨立地為0～12的整數，Boc為第三丁氧基羰基。 The group whose bonding position is not fixed to the carbon atom constituting the ring means that the bonding position on the ring is arbitrary. Furthermore, the bonding position of the amino group on the cyclohexane ring or the benzene ring is any position other than the bonding position of G ²¹ , G ²² or G ³³ .

In formula (DI-4-a) and formula (DI-4-b), R ²⁰ is independently a hydrogen atom or a methyl group. In the formula (DI-4-f) and the formula (DI-4-g), m is each independently an integer of 0 to 12, and Boc is a tertiary butoxycarbonyl group.

式（DI-5-a）中，q分別獨立地為0～6的整數。R ⁴⁴為氫原子、羥基、碳數1～6的烷基或碳數1～6的烷氧基。

In formula (DI-5-a), q is an integer of 0-6 each independently. R ⁴⁴ is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbons, or an alkoxy group having 1 to 6 carbons.

式（DI-11）中，r為0或1。式（DI-8）～式（DI-11）中，鍵結於環上的氨基的鍵結位置為任意位置。

In formula (DI-11), r is 0 or 1. In formula (DI-8) to formula (DI-11), the bonding position of the amino group bonded to the ring is any position.

式（DI-12）中，R ²¹及R ²²分別獨立地為碳數1～3的烷基或苯基，G ²³獨立地為碳數1～6的伸烷基、亞苯基或經烷基取代的亞苯基，w為1～10的整數。 式（DI-13）中，R ²³獨立地為碳數1～5的烷基、碳數1～5的烷氧基或-Cl，p獨立地為0～3的整數，q為0～4的整數。 式（DI-14）中，環B為單環的雜環式芳香族基，R ²⁴為氫原子、氟原子、氯原子、碳數1～6的烷基、烷氧基、烯基或炔基，q獨立地為0～4的整數。在q為2以上時，多個R ²⁴可相互相同，也可不同。 式（DI-15）中，環C為雜環式芳香族基或雜環式脂肪族基。 式（DI-16）中，G ²⁴為單鍵、碳數2～6的伸烷基或1,4-亞苯基，r為0或1。而且，鍵結位置未固定於構成環的碳原子上的基表示在所述環上的鍵結位置為任意。式（DI-13）～式（DI-16）中，鍵結於環上的氨基的鍵結位置為任意位置。

In formula (DI-12), R ²¹ and R ²² are independently alkyl or phenyl with 1 to 3 carbons, and G ²³ is independently alkylene, phenylene or alkylene with 1 to 6 carbons. A phenylene group substituted with a group, w is an integer of 1-10. In formula (DI-13), ^R23 is independently an alkyl group with 1 to 5 carbons, an alkoxy group with 1 to 5 carbons, or -Cl, p is independently an integer of 0 to 3, and q is 0 to 4 an integer of . In the formula (DI-14), ring B is a monocyclic heterocyclic aromatic group, ^R24 is a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group with 1 to 6 carbons, an alkoxy group, an alkenyl group or an alkyne group base, q is an integer of 0-4 independently. When q is 2 or more, a plurality of R ²⁴ may be the same as or different from each other. In formula (DI-15), ring C is a heterocyclic aromatic group or a heterocyclic aliphatic group. In the formula (DI-16), G ²⁴ is a single bond, an alkylene group having 2 to 6 carbon atoms, or a 1,4-phenylene group, and r is 0 or 1. Furthermore, a group whose bonding position is not fixed to a carbon atom constituting the ring means that the bonding position on the ring is arbitrary. In formula (DI-13) to formula (DI-16), the bonding position of the amino group bonded to the ring is any position.

式（DI-1-7）及式（DI-1-8）中，k分別獨立地為1～3的整數。式（DI-1-9）中，v分別獨立地為1～6的整數。 The example of the diamine represented by a formula (DI-1) is shown in following formula (DI-1-1) - a formula (DI-1-9).

In formula (DI-1-7) and formula (DI-1-8), k is an integer of 1-3 each independently. In Formula (DI-1-9), v is an integer of 1-6 each independently.

In the following formula (DI-2-1), formula (DI-2-2), formula (DI-3-1) to formula (DI-3-3), formula (DI-2) to formula (DI -3) Examples of diamines represented.

式（DI-4-20）及式（DI-4-21）中，m分別獨立地為1～12的整數。

The example of the diamine represented by a formula (DI-4) is shown in following formula (DI-4-1) - a formula (DI-4-27).

In Formula (DI-4-20) and Formula (DI-4-21), m is an integer of 1-12 each independently.

式（DI-5-1）中，m為1～12的整數。 The example of the diamine represented by a formula (DI-5) is shown in following formula (DI-5-1) - a formula (DI-5-50).

In formula (DI-5-1), m is an integer of 1-12.

式（DI-5-12）及式（DI-5-13）中，m分別獨立地為1～12的整數。

In formula (DI-5-12) and formula (DI-5-13), m is an integer of 1-12 each independently.

式（DI-5-16）中，v為1～6的整數。

In formula (DI-5-16), v is an integer of 1-6.

式（DI-5-30）中，k為1～5的整數。

In formula (DI-5-30), k is an integer of 1-5.

式（DI-5-35）～式（DI-5-37）及式（DI-5-39）中，m分別獨立地為1～12的整數，式（DI-5-38）及式（DI-5-39）中，k分別獨立地為1～5的整數，式（DI-5-40）中，n為1或2的整數。

In formula (DI-5-35) ~ formula (DI-5-37) and formula (DI-5-39), m is independently an integer from 1 to 12, and formula (DI-5-38) and formula ( In DI-5-39), k is an integer of 1 to 5 each independently, and in formula (DI-5-40), n is an integer of 1 or 2.

式（DI-5-42）～式（DI-5-44）中，e分別獨立地為2～10的整數，式（DI-5-45）中，R ⁴³為氫原子、(第三丁氧基羰基)氨基或雙(第三丁氧基羰基)氨基。式（DI-5-42）～式（DI-5-44）中，Boc為第三丁氧基羰基。

In formula (DI-5-42) to formula (DI-5-44), e is independently an integer of 2 to 10, and in formula (DI-5-45), R ⁴³ is a hydrogen atom, (the third oxycarbonyl)amino or bis(tert-butoxycarbonyl)amino. In the formula (DI-5-42) to the formula (DI-5-44), Boc is a tertiary butoxycarbonyl group.

The example of the diamine represented by a formula (DI-6) is shown in following formula (DI-6-1) - a formula (DI-6-7).

式（DI-7-3）及式（DI-7-4）中，m分別獨立地為1～12的整數，n獨立地為1或2。 The example of the diamine represented by a formula (DI-7) is shown in following formula (DI-7-1) - a formula (DI-7-11).

In Formula (DI-7-3) and Formula (DI-7-4), m is an integer of 1-12 each independently, and n is 1 or 2 independently.

The example of the diamine represented by a formula (DI-8) is shown in following formula (DI-8-1) - a formula (DI-8-4).

The example of the diamine represented by a formula (DI-9) is shown in following formula (DI-9-1) - a formula (DI-9-3).

Examples of the diamine represented by the formula (DI-10) are shown in the following formula (DI-10-1) and formula (DI-10-2).

The example of the diamine represented by a formula (DI-11) is shown in following formula (DI-11-1) - a formula (DI-11-3).

An example of the diamine represented by the formula (DI-12) is shown in the following formula (DI-12-1).

The example of the diamine represented by a formula (DI-13) is shown in following formula (DI-13-1) - a formula (DI-13-13).

The example of the diamine represented by a formula (DI-14) is shown in following formula (DI-14-1) - a formula (DI-14-9).

The example of the diamine represented by a formula (DI-15) is shown in following formula (DI-15-1) - a formula (DI-15-12).

An example of the diamine represented by the formula (DI-16) is shown in the following formula (DI-16-1).

式（DIH-1）中，G ²⁵為單鍵、碳數1～20的伸烷基、-CO-、-O-、-S-、-SO ₂-、-C(CH ₃) ₂-或-C(CF ₃) ₂-。 式（DIH-2）中，環D為環己烷環、苯環或萘環，所述基的至少一個氫原子可經甲基、乙基或苯基取代。 式（DIH-3）中，環E分別獨立地為環己烷環或苯環，所述基的至少一個氫原子可經甲基、乙基或苯基取代。多個環E可相互相同，也可不同。Y為單鍵、碳數1～20的伸烷基、-CO-、-O-、-S-、-SO ₂-、-C(CH ₃) ₂-或-C(CF ₃) ₂-。 式（DIH-2）及式（DIH-3）中，鍵結於環上的醯肼基的鍵結位置為任意位置。 Next, dihydrazide used as a raw material for the polymer of the present invention will be described. Examples of known dihydrazides having no side chains include compounds represented by any one of the following formulas (DIH-1) to (DIH-3).

In the formula (DIH-1), G ²⁵ is a single bond, an alkylene group with 1 to 20 carbons, -CO-, -O-, -S-, -SO ₂ -, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -. In the formula (DIH-2), the ring D is a cyclohexane ring, a benzene ring or a naphthalene ring, and at least one hydrogen atom of the said group may be substituted by a methyl group, an ethyl group or a phenyl group. In the formula (DIH-3), the ring E is independently a cyclohexane ring or a benzene ring, and at least one hydrogen atom of the said group may be substituted by a methyl group, an ethyl group or a phenyl group. A plurality of rings E may be the same as or different from each other. Y is a single bond, an alkylene group having 1 to 20 carbon atoms, -CO-, -O-, -S-, -SO ₂ -, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -. In the formula (DIH-2) and the formula (DIH-3), the bonding position of the hydrazine group bonded to the ring is an arbitrary position.

式（DIH-1-2）中，m為1～12的整數。 In the following formula (DIH-1-1), formula (DIH-1-2), formula (DIH-2-1) ~ formula (DIH-2-3), formula (DIH-3-1) ~ formula ( DIH-3-6) shows an example of the compound represented by any one of formula (DIH-1) to formula (DIH-3).

In formula (DIH-1-2), m is an integer of 1-12.

Diamines suitable for the purpose of increasing the pretilt angle will be described. The compound of this invention can be used suitably for the liquid crystal aligning agent used for the transverse electric field type liquid crystal display element, However, It can also use together with the following diamine and can use it to increase a pretilt angle. As diamines suitable for the purpose of increasing the pretilt angle and having side chain groups, formula (DI-31) to formula (DI-35) and formula (DI-36-1) to formula (DI-36-8 ) Diamines represented by either one.

In the formula (DI-31), G ²⁶ is a single bond, -O-, -COO-, -OCO-, -CO-, -CONH-, -CH ₂ O-, -OCH ₂ -, -CF ₂ O- , -OCF ₂ - or -(CH ₂ ) _ma -, ma is an integer of 1-12. Preferable examples of ^G26 are single bond, -O-, -COO-, -OCO-, _-CH2O- , and alkylene groups having 1 to 3 carbon atoms, and particularly preferred examples are single bond, -O-, - COO-, -OCO-, -CH ₂ O-, -CH ₂ - and -CH ₂ CH ₂ -. R ²⁵ is an alkyl group having 3 to 30 carbon atoms, a phenyl group, a group having a steroid skeleton, or a group represented by the following formula (DI-31-a). In the alkyl group, at least one hydrogen atom may be substituted by a fluorine atom, and at least one -CH ₂ - may be substituted by -O-, -CH=CH- or -C≡C-. The hydrogen atom of the phenyl can be fluorine atom, methyl, methoxy, fluoromethyloxy, difluoromethyloxy, trifluoromethyloxy, an alkyl group with 3 to 30 carbons or a carbon number 3 to 30 alkoxy substitutions. The bonding position of the amino group bonded to the benzene ring means any position on the ring, and the bonding position is preferably meta-position or para-position. That is, when the bonding position of the group "R ²⁵ -G ²⁶ -" is defined as 1-position, the two bonding positions are preferably 3-position and 5-position or 2-position and 5-position.

式（DI-31-a）中，G ²⁷、G ²⁸及G ²⁹為鍵結基，它們分別獨立地為單鍵或碳數1～12的伸烷基，所述伸烷基的一個以上的-CH ₂-可經-O-、-COO-、-OCO-、-CONH-或-CH=CH-取代。環B ²¹、環B ²²、環B ²³及環B ²⁴分別獨立地為1,4-亞苯基、1,4-亞環己基、1,3-二噁烷-2,5-二基、嘧啶-2,5-二基、吡啶-2,5-二基、萘-1,5-二基、萘-2,7-二基或蒽-9,10-二基，環B ²¹、環B ²²、環B ²³及環B ²⁴中，至少一個氫原子可經氟原子或甲基取代，s、t及u分別獨立地為0～2的整數，它們的合計為1～5，在s、t或u為2時，各個括弧內的兩個鍵結基可相同，也可不同，而且，兩個環可相同，也可不同。R ²⁶為氫原子、氟原子、羥基、碳數1～30的烷基、碳數1～30的氟取代烷基、碳數1～30的烷氧基、氰基、氟甲基氧基、二氟甲基氧基或三氟甲基氧基，所述碳數1～30的烷基的至少一個-CH ₂-可經下述式（DI-31-b）所表示的二價基取代。

式（DI-31-b）中，R ²⁷及R ²⁸分別獨立地為碳數1～3的烷基，v為1～6的整數。R ²⁶的優選例為碳數1～30的烷基及碳數1～30的烷氧基。

In the formula (DI-31-a), G ²⁷ , G ²⁸ and G ²⁹ are bonding groups, which are each independently a single bond or an alkylene group with 1 to 12 carbons, and one or more of the alkylene groups -CH ₂ - may be substituted by -O-, -COO-, -OCO-, -CONH- or -CH=CH-. Ring B ²¹ , Ring B ²² , Ring B ²³ and Ring B ²⁴ are each independently 1,4-phenylene, 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, Pyrimidine-2,5-diyl, pyridine-2,5-diyl, naphthalene-1,5-diyl, naphthalene-2,7-diyl or anthracene-9,10-diyl, ring B ²¹ , ring In B ²² , ring B ²³ , and ring B ²⁴ , at least one hydrogen atom may be substituted by a fluorine atom or a methyl group, s, t, and u are each independently an integer from 0 to 2, and the total of them is 1 to 5. In s When , t or u is 2, the two bonding groups in each parenthesis may be the same or different, and the two rings may be the same or different. ^R26 is a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group with 1 to 30 carbons, a fluorine-substituted alkyl group with 1 to 30 carbons, an alkoxy group with 1 to 30 carbons, a cyano group, a fluoromethyloxy group, Difluoromethyloxy or trifluoromethyloxy, at least one -CH ₂ - of the alkyl group with 1 to 30 carbons can be substituted by a divalent group represented by the following formula (DI-31-b) .

In the formula (DI-31-b), R ²⁷ and R ²⁸ are each independently an alkyl group having 1 to 3 carbons, and v is an integer of 1 to 6. Preferred examples of R ²⁶ are alkyl having 1 to 30 carbons and alkoxy having 1 to 30 carbons.

式（DI-32）及式（DI-33）中，G ³⁰獨立地為單鍵、-CO-或-CH ₂-，R ²⁹獨立地為氫原子或甲基，R ³⁰為氫原子、碳數1～20的烷基或碳數2～20的烯基。式（DI-33）中的苯環的至少一個氫原子可經碳數1～20的烷基或苯基取代。而且，鍵結位置未固定於構成環的任一個碳原子上的基表示在所述環上的鍵結位置為任意。優選為式（DI-32）中的兩個基“-亞苯基-G ³⁰-O-”的其中一個鍵結於類固醇核的3位，另一個鍵結於類固醇核的6位。式（DI-33）中的兩個基“-亞苯基-G ³⁰-O-”在苯環上的鍵結位置優選為相對於類固醇核的鍵結位置，分別為間位或對位。式（DI-32）及式（DI-33）中，鍵結於苯環上的氨基表示在所述環上的鍵結位置為任意。

In formula (DI-32) and formula (DI-33), G ³⁰ is independently a single bond, -CO- or -CH ₂ -, R ²⁹ is independently a hydrogen atom or a methyl group, R ³⁰ is a hydrogen atom, carbon An alkyl group having 1 to 20 carbons or an alkenyl group having 2 to 20 carbons. At least one hydrogen atom of the benzene ring in the formula (DI-33) may be substituted with an alkyl group or phenyl group having 1 to 20 carbon atoms. Furthermore, a group whose bonding position is not fixed to any carbon atom constituting the ring means that the bonding position on the ring is arbitrary. Preferably, one of the two groups "-phenylene-G ³⁰ -O-" in the formula (DI-32) is bonded to the 3-position of the steroid nucleus, and the other is bonded to the 6-position of the steroid nucleus. The bonding positions of the two groups "-phenylene-G ³⁰ -O-" in the formula (DI-33) on the benzene ring are preferably meta-position or para-position relative to the steroid core. In formula (DI-32) and formula (DI-33), the amino group bonded to the benzene ring means that the bonding position on the ring is arbitrary.

式（DI-34）及式（DI-35）中，G ³¹獨立地為-O-或碳數1～6的伸烷基，G ³²為單鍵或碳數1～3的伸烷基。R ³¹為氫原子或碳數1～20的烷基，所述烷基的至少一個-CH ₂-可經-O-、-CH=CH-或-C≡C-取代。R ³²為碳數6～22的烷基，R ³³為氫原子或碳數1～22的烷基。環B ²⁵為1,4-亞苯基或1,4-亞環己基，r為0或1。而且，鍵結於苯環上的氨基表示在所述環上的鍵結位置為任意，優選為獨立地相對於G ³¹的鍵結位置而為間位或對位。

In formula (DI-34) and formula (DI-35), G ³¹ is independently -O- or an alkylene group having 1 to 6 carbons, and G ³² is a single bond or an alkylene group having 1 to 3 carbons. R ³¹ is a hydrogen atom or an alkyl group having 1 to 20 carbons, at least one -CH ₂ - of the alkyl group may be substituted by -O-, -CH=CH- or -C≡C-. R ³² is an alkyl group with 6 to 22 carbons, and R ³³ is a hydrogen atom or an alkyl group with 1 to 22 carbons. Ring B ²⁵ is 1,4-phenylene or 1,4-cyclohexylene, and r is 0 or 1. Furthermore, the amino group bonded to the benzene ring means that the bonding position on the ring is arbitrary, and is preferably meta-position or para-position independently of the bonding position of ^G31 .

Examples of the compound represented by the formula (DI-31) are shown in the following formula (DI-31-1) to formula (DI-31-55).

In formula (DI-31-1) to formula (DI-31-11), R ³⁴ is each independently an alkyl group with 1 to 30 carbons or an alkoxy group with 1 to 30 carbons, preferably 5 to 30 carbons. 25 alkyl or alkoxy having 5 to 25 carbons. R ³⁵ are each independently an alkyl group having 1 to 30 carbons or an alkoxy group having 1 to 30 carbons, preferably an alkyl group having 3 to 25 carbons or an alkoxy group having 3 to 25 carbons.

In formula (DI-31-12) to formula (DI-31-17), R ³⁶ is each independently an alkyl group having 4 to 30 carbons, preferably an alkyl group having 6 to 25 carbons. R ³⁷ are each independently an alkyl group having 6 to 30 carbons, preferably an alkyl group having 8 to 25 carbons.

In formulas (DI-31-18) to formulas (DI-31-43), R ³⁸ are each independently an alkyl group with 1 to 20 carbons or an alkoxy group with 1 to 20 carbons, preferably 3 to 20 carbons. An alkyl group with 20 carbon atoms or an alkoxy group with 3 to 20 carbon atoms. ^R39 are each independently a hydrogen atom, a fluorine atom, an alkyl group with 1 to 30 carbons, an alkoxy group with 1 to 30 carbons, a cyano group, a fluoromethyloxy group, a difluoromethyloxy group or a trifluoromethyl group The oxy group is preferably an alkyl group having 3 to 25 carbons or an alkoxy group having 3 to 25 carbons. Furthermore, ^G33 is an alkylene group having 1 to 20 carbon atoms.

Examples of the compound represented by the formula (DI-32) are shown in the following formulas (DI-32-1) to (DI-32-4).

Examples of the compound represented by the formula (DI-33) are shown in the following formulas (DI-33-1) to (DI-33-8).

式（DI-34-1）～式（DI-34-12）中，R ⁴⁰分別獨立地為氫原子或碳數1～20的烷基，優選為氫原子或碳數1～10的烷基，而且，R ⁴¹分別獨立地為氫原子或碳數1～12的烷基。 Examples of the compound represented by the formula (DI-34) are shown in the following formula (DI-34-1) to formula (DI-34-12).

In formula (DI-34-1) to formula (DI-34-12), R ⁴⁰ is each independently a hydrogen atom or an alkyl group with 1 to 20 carbons, preferably a hydrogen atom or an alkyl group with 1 to 10 carbons , and, R ⁴¹ are each independently a hydrogen atom or an alkyl group having 1 to 12 carbons.

式（DI-35-1）～式（DI-35-3）中，R ³⁷分別獨立地為碳數6～30的烷基，R ⁴¹分別獨立地為氫原子或碳數1～12的烷基。 Examples of the compound represented by the formula (DI-35) are shown in the following formula (DI-35-1) to formula (DI-35-3).

In formula (DI-35-1) to formula (DI-35-3), R ³⁷ is independently an alkyl group with 6 to 30 carbons, and R ⁴¹ is independently a hydrogen atom or an alkane with 1 to 12 carbons base.

式（DI-36-1）～式（DI-36-8）中，R ⁴²分別獨立地為碳數3～30的烷基。 Compounds represented by formula (DI-36-1) to formula (DI-36-8) are shown below.

In formula (DI-36-1) to formula (DI-36-8), R ⁴² is each independently an alkyl group having 3 to 30 carbon atoms.

Among the above-mentioned diamines, suitable materials for enhancing various properties of the liquid crystal alignment film described later will be described. When emphasizing the improvement of liquid crystal alignment, it is preferable to use formula (DI-1-3), formula (DI-5-1), formula (DI-5-5), formula (DI-5-9), formula (DI-5-12), formula (DI-5-13), formula (DI-5-29), formula (DI-6-7), formula (DI-7-3) or formula (DI-11- 2) Compounds represented. In formula (DI-5-1), m=2-8 is preferable, and m=4-8 is more preferable. In formula (DI-5-12), m=2-6 is preferable, and m=5 is more preferable. In the formula (DI-5-13), m=1 or 2 is preferable, and m=1 is more preferable.

In the case of emphasizing the improvement of transmittance, it is preferable to use formula (DI-1-3), formula (DI-2-1), formula (DI-5-1), formula (DI-5-5), formula ( DI-5-24) or a diamine represented by formula (DI-7-3), more preferably a compound represented by formula (DI-2-1). In formula (DI-5-1), m=2-8 is preferable, and m=8 is more preferable. In the formula (DI-7-3), m=2 or 3 and n=1 or 2 are preferable, and m=3 and n=1 are more preferable.

When it is important to improve the VHR of the liquid crystal display element, it is preferable to use formula (DI-2-1), formula (DI-4-1), formula (DI-4-2), formula (DI-4-10) , formula (DI-4-15), formula (DI-4-22), formula (DI-5-1), formula (DI-5-28), formula (DI-5-30) or formula (DI- The compound represented by 13-1) is more preferably a diamine represented by formula (DI-2-1), formula (DI-5-1) or formula (DI-13-1). In formula (DI-5-1), m=1 is preferable. In formula (DI-5-30), k=2 is preferable.

As one of methods for preventing burn marks, it is effective to increase the rate of relaxation of residual charges (residual DC) in the liquid crystal alignment film by reducing the volume resistance value of the liquid crystal alignment film. When emphasizing the above purpose, it is preferable to use formula (DI-4-1), formula (DI-4-2), formula (DI-4-10), formula (DI-4-15), formula ( DI-5-1), formula (DI-5-12), formula (DI-5-13), formula (DI-5-28), formula (DI-4-20), formula (DI-4-21 ), the compound represented by formula (DI-7-12) or formula (DI-16-1), more preferably the compound represented by formula (DI-4-1), formula (DI-5-1) or formula (DI-5 -13) represented by the compound. In formula (DI-5-1), m=2-8 is preferable, and m=4-8 is more preferable. In formula (DI-5-12), m=2-6 is preferable, and m=5 is more preferable. In the formula (DI-5-13), m=1 or 2 is preferable, and m=1 is more preferable. In the formula (DI-7-12), m=3 or 4 is preferable, and m=4 is more preferable.

In the raw material composition used as a raw material of the polymer of the present invention, a part of diamines may be substituted with at least one selected from the group consisting of monoamine and monohydrazine. Regarding the ratio of substitution, it is preferable that the ratio of at least one selected from the group consisting of monoamines and monohydrazides relative to diamines is in the range of 40 mol % or less. Such substitution can cause the termination of the polymerization reaction when producing polyamic acid, and can inhibit the further progress of the polymerization reaction. Therefore, by such substitution, the molecular weight of the obtained polymer (polyamic acid or its derivatives) can be easily controlled, for example, the coating properties of the liquid crystal alignment agent can be improved without impairing the effect of the present invention. As long as the effects of the present invention are not impaired, the diamines which may be substituted with monoamine or monohydrazine may be one kind or two or more kinds. Examples of the monoamine include: aniline, 4-hydroxyaniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-decylamine, Monoamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, p-aminophenyltrimethoxy Silane and 3-Aminopropyltriethoxysilane.

When the polymer of the present invention is polyamic acid or a derivative thereof, the raw material composition may further contain a monoisocyanate compound as a monomer. By including a monoisocyanate compound as a monomer, the terminal of the obtained polyamic acid or its derivative is modified and the molecular weight is adjusted. By using the terminal-modified polyamic acid or its derivatives, for example, the coating properties of the liquid crystal alignment agent can be improved without impairing the effect of the present invention. From such a viewpoint, it is preferable that content of the monoisocyanate compound in a monomer is 1 mol% - 10 mol% with respect to the total amount of the diamine in a monomer, and tetracarboxylic dianhydride. As said monoisocyanate compound, a phenyl isocyanate and a naphthyl isocyanate are mentioned, for example.

The liquid crystal alignment agent of the present invention may contain one kind of the polymer of the present invention, or may mix the polymer of the present invention and a polymer other than the present invention. In addition, in this specification, the liquid crystal alignment agent containing one kind of said polymer is sometimes called a single-layer type liquid crystal alignment agent. A liquid crystal alignment agent in which two or more polymers are mixed is sometimes called a blended liquid crystal alignment agent. Blended liquid crystal alignment agents are especially used when VHR reliability or other electrical characteristics are valued.

As a polymer other than this invention used for a blend type liquid crystal aligning agent, any one or more of polyamic acid and a polyamic acid derivative is preferable. As polymers other than the present invention, with regard to polyamic acid and polyamic acid derivatives, except for including a compound having a photoreactive structure and formula (1-1) or formula (1-2) as a raw material composition ) other than the compounds represented by ), the description of the polymer of the present invention can be referred to.

In the case of using two-component polymers, for example, there are the following forms: one of them is selected to have excellent performance in liquid crystal alignment ability, and the other is selected to have excellent properties for improving the electrical characteristics of liquid crystal display elements. Polymers with high performance are suitable for obtaining an alignment agent with a good balance between liquid crystal alignment and electrical properties.

In this case, by controlling the structure and molecular weight of each polymer, it is possible to form a thin film by applying a liquid crystal alignment agent obtained by dissolving these polymers in a solvent on a substrate and pre-drying as described later. In this method, the polymer having excellent performance in liquid crystal alignment ability is segregated in the upper layer of the film, and the polymer having excellent performance in improving the electrical characteristics of the liquid crystal display element is segregated in the lower layer of the film. Among the polymers present in a mixture, a phenomenon that a polymer with a small surface energy is separated into an upper layer and a polymer with a large surface energy is separated into a lower layer can be used. Confirmation of such layer separation can be confirmed by the following method: the surface energy of the formed liquid crystal alignment film is the same as or close to the surface energy of a film formed of a liquid crystal alignment agent containing only polymers intended to segregate in the upper layer value.

As a method for developing layer separation, reducing the molecular weight of the polymer to be segregated in the upper layer is also mentioned.

In the liquid crystal alignment agent including the mixture of polymers, layer separation can also be expressed by using polyimide as the polymer to be segregated in the upper layer.

The compound represented by formula (1-1) or formula (1-2) can be used as a raw material of the polymer segregated in the upper layer of the film, and can also be used as a raw material of the polymer segregated in the lower layer of the film. In addition, It can also be used as a raw material for two types of polymers, more preferably as a raw material for a polymer segregated in the upper layer of the film.

The compound represented by formula (2) or formula (3) can be used as a raw material of the polymer segregated in the upper layer of the film, and can also be used as a raw material of the polymer segregated in the lower layer of the film. In addition, it can also be used as The raw materials of the two kinds of polymers are more preferably used as the raw materials of the polymers segregated in the upper layer of the film.

As formula (1-1) or formula (1-2) for synthesizing the polyamic acid or its derivatives segregated in the upper layer of the film and the polyamic acid or its derivatives segregated in the lower layer of the film ) can be selected from the known tetracarboxylic dianhydrides exemplified above without limitation.

Tetracarboxylic dianhydride used to synthesize polyamic acid or derivatives thereof segregated in the upper layer of the film is preferably formula (AN-1-1), formula (AN-1-2), formula (AN-2-1 ), formula (AN-3-1), formula (AN-4-5), formula (AN-4-17) or formula (AN-4-21), more preferably formula (AN-4 -17) or formula (AN-4-21). In the formula (AN-4-17), m=4-8 is preferable.

As the tetracarboxylic dianhydride used to synthesize polyamic acid or derivatives thereof segregated in the lower layer of the film, formula (AN-1-1), formula (AN-1-13), formula (AN-2 -1), the compound represented by formula (AN-3-2) or formula (AN-4-21), more preferably the compound represented by formula (AN-1-1), formula (AN-2-1) or formula (AN -3-2).

The tetracarboxylic dianhydride used to synthesize the polyamic acid or its derivatives segregated in the lower layer of the film preferably contains 10 mol% or more of aromatic tetracarboxylic dianhydride in the total amount of tetracarboxylic dianhydride, and more preferably Preferably, it contains 30 mol% or more.

Diamines other than compounds represented by formula (2) for synthesizing polyamic acid or its derivatives segregated in the upper layer of the film and polyamic acid or its derivatives segregated in the lower layer of the film, It can be selected from the above-mentioned exemplified known diamines without limitation.

As diamines for synthesizing polyamic acid or derivatives thereof segregated in the upper layer of the film, it is preferable to use formula (DI-4-1), formula (DI-4-13), formula (DI-4- 15), a compound represented by formula (DI-5-1), formula (DI-7-3) or formula (DI-13-1). Among them, it is more preferable to use a compound represented by formula (DI-4-13), formula (DI-4-15), formula (DI-5-1) or formula (DI-13-1). In formula (DI-5-1), m=4-8 is preferable. In formula (DI-7-3), m=3 and n=1 are preferable.

As diamines for synthesizing polyamic acid or derivatives thereof segregated in the lower layer of the film, formula (DI-4-1), formula (DI-4-2), formula (DI-4-10 ), formula (DI-4-18), formula (DI-4-19), formula (DI-5-1), formula (DI-5-9), formula (DI-5-28), formula (DI -5-30), the compound represented by formula (DI-13-1) or formula (DIH-1-2). In formula (DI-5-1), a compound with m=1 or 2 is preferable, and in formula (DI-5-30), a compound with k=2 is preferable. Among them, formula (DI-4-1), formula (DI-4-18), formula (DI-4-19), formula (DI-5-9), formula (DI-13-1) or A compound represented by the formula (DIH-1-2).

With respect to all diamines, the diamines used to synthesize polyamic acid or its derivatives segregated in the lower layer of the film preferably contain 30 mol% or more of aromatic diamines and aromatic dihydrazides. At least one of the groups, more preferably 50 mol% or more.

The total amount of polyamic acid or its derivatives segregated in the upper layer of the film relative to the polyamic acid or its derivatives segregated in the upper layer of the film and the polyamic acid or its derivatives segregated in the lower layer of the film The ratio is preferably 5% by weight to 60% by weight, more preferably 20% by weight to 50% by weight.

The polyamic acid or its derivatives of the present invention may be a block polymer comprising a first polymer chain and a second polymer chain having a different structure from the first polymer chain. In addition, the block polymer may further include another polymer chain having a structure different from that of the first polymer chain and the second polymer chain. For example, a block polymer of polyamic acid can be obtained by combining a solution of a specific polyamic acid (PAA1) represented by the formula (PAA) with X ¹ and X ² different from the polyamic acid (PAA1). A solution of polyamide acid (PAA2) is mixed and heated to form. The polyamic acid block polymer thus formed includes a block represented by (PAA1) _n1 and a block represented by (PAA2) _n2 . In (PAA1) _n1 and (PAA2) _n2 , n1 and n2 are each independently an integer of 1 or more, preferably an integer of 2 or more each independently. In block polymers, the polymer chains using the compounds represented by formula (1-1) or formula (1-2) and formula (2) or formula (3) as the raw material composition can be either, or It may be two or more kinds of polymer chains, and may be all polymer chains.

Here, the polyamic acid block polymer can be synthesized by mixing and heating two or more kinds of polyamic acids individually, respectively. Alternatively, two or more types of polyamic acid can be synthesized in the same reaction vessel as in the same reaction vessel after the first polyamic acid is synthesized by adding the raw material of the second polyamic acid to the same reaction vessel. , and then heated to synthesize.

In the case of producing a block polymer, in the raw material composition used as the raw material of the polymer of the present invention, the formula (1-1) or the formula (1 The compound represented by -2) is preferably 10 mol% or more, more preferably 20 mol% or more. The compound represented by formula (2) or formula (3) is preferably 10 mol % or more, more preferably 20 mol % or more, based on the total amount of diamines used as a raw material.

In addition, the liquid crystal alignment agent of the present invention may further contain a solvent from the viewpoint of the coating property of the liquid crystal alignment agent or the adjustment of the concentration of the polyamic acid or its derivative. The solvent can be used without particular limitation as long as it has the ability to dissolve the polymer component. The solvent broadly includes solvents generally used in the production process or use of polymer components such as polyamic acid and soluble polyimide, and can be appropriately selected according to the purpose of use. The solvent may be one kind, or a mixture of two or more solvents.

Examples of the solvent include a solvate-friendly solvent for the polyamic acid or its derivatives, or other solvents for the purpose of improving coatability.

Examples of aprotic polar organic solvents that are solvatophilic to polyamic acid or derivatives thereof include: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and dimethylimidazolidone , N-methylcaprolactamide, N-methylacrylamide, N,N-dimethylacetamide, dimethylsulfide, N,N-dimethylformamide, N,N- Diethylformamide, diethylacetamide, N,N-dimethylisobutylamide, γ-butyrolactone and γ-valerolactone, etc. Among these solvents, N-methyl-2-pyrrolidone, dimethylimidazolidinone, γ-butyrolactone, or γ-valerolactone are preferable.

Examples of other solvents for the purpose of improving coatability, etc. include ethylene glycol monoalkyl ethers such as ethylene glycol monobutyl ether and ethylene glycol monotertiary butyl ether, diethylene glycol monoethyl ether, etc. Diethylene glycol dialkyl ethers such as ethylene glycol monoalkyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, and diethylene glycol butyl methyl ether. In addition, propylene glycol monomethyl ether, propylene glycol monoalkyl ethers such as 1-butoxy-2-propanol, dipropylene glycol monoalkyl ethers such as dipropylene glycol monomethyl ether, triethylene glycol monoalkyl ether, butyl solvent, etc. Cellulose acetate, phenyl acetate and ester compounds such as these acetates. Further, dialkyl malonate such as diethyl malonate, alkyl lactate, diisobutyl ketone, diacetone alcohol, 3-methyl-3-methoxybutanol, 4- Methyl-2-pentanol, diisobutylcarbinol, tetralin and isophorone.

Among these solvents, diisobutyl ketone, 4-methyl-2-pentanol, diisobutyl carbinol, ethylene glycol monobutyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono Diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, 1-butoxy-2-propanol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether or butyl Cellulose acetate.

The solid content concentration in the liquid crystal alignment agent of the present invention is not particularly limited, as long as the most suitable value is selected in combination with various coating methods described below. Usually, in order to suppress unevenness and pinholes during coating, it is preferably 0.1% by weight to 30% by weight, more preferably 1% by weight to 10% by weight, based on the weight of the varnish.

The preferred range of the viscosity of the liquid crystal alignment agent of the present invention varies depending on the coating method, the concentration of polyamic acid or its derivatives, the type of polyamic acid or its derivatives used, and the type and ratio of solvents. For example, in the case of applying by a printing machine, it is 5 mPa·s to 100 mPa·s (more preferably 10 mPa·s to 80 mPa·s). If it is 5 mPa·s or more, it will be easy to obtain a sufficient film thickness, and if it is 100 mPa·s or less, it will be easy to suppress printing unevenness. In the case of coating by spin coating, it is suitable to be 5 mPa·s to 200 mPa·s (more preferably 10 mPa·s to 100 mPa·s). When coating is performed using an inkjet coating device, it is suitable to be 5 mPa·s to 50 mPa·s (more preferably 5 mPa·s to 20 mPa·s). The viscosity of the liquid crystal alignment agent can be measured by rotational viscometry, for example, can be measured using a rotational viscometer (TVE-20L type manufactured by Toki Sangyo) (measurement temperature: 25° C.).

The liquid crystal alignment agent of the present invention may further contain various additives. In order to improve various characteristics of the alignment film, various additives may be selected and used according to various purposes. Examples are shown below.

＜Alkenyl-substituted nadicimide compounds＞ For example, the liquid crystal alignment agent of the present invention may further contain an alkenyl-substituted nadicimide compound for the purpose of stabilizing the electrical characteristics of a liquid crystal display element over a long period of time. One type of alkenyl-substituted nadicimide compound may be used, or two or more types may be used in combination. For the above purpose, the content of the alkenyl-substituted nadicimide compound is preferably 1% by weight to 50% by weight, more preferably 1% by weight to 30% by weight, based on the polyamic acid or its derivatives, More preferably, it is 1 weight% - 20 weight%. The alkenyl-substituted nadicimide compound is preferably a compound soluble in a solvent in which the polyamic acid or its derivative used in the present invention is dissolved. Preferred alkenyl-substituted nadicimide compounds include alkenyl-substituted sodium compounds disclosed in JP-A-2008-096979, JP-A-2009-109987, and JP-A-2013-242526. dicimide compound. As a particularly preferable alkenyl-substituted nadicimide compound, bis{4-(allylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide)phenyl} Methane, N,N'-m-xylylene-bis(allylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide) or N,N'-hexamethylene - bis(allylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide).

<Compounds having radically polymerizable unsaturated double bonds> For example, the liquid crystal alignment agent of the present invention may further contain a compound having a radically polymerizable unsaturated double bond for the purpose of stabilizing the electrical characteristics of a liquid crystal display element over a long period of time. The compound having a radically polymerizable unsaturated double bond may be one kind of compound, or two or more kinds of compounds. In addition, no alkenyl-substituted nadicimide compound is included in the compound having a radically polymerizable unsaturated double bond. Among compounds having a radically polymerizable unsaturated double bond, preferred compounds include: N,N'-methylenebisacrylamide, N,N'-dihydroxyethylene-bisacrylamide , ethylene diacrylate, 4,4'-methylene bis(N,N-dihydroxyethylene acrylate aniline), triallyl cyanurate; and Japanese Patent Laid-Open No. 2009-109987 , a compound having a radically polymerizable unsaturated double bond disclosed in JP-A-2013-242526, International Publication No. 2014/119682, and International Publication No. 2015/152014. For the purpose, the content of the compound having a radically polymerizable unsaturated double bond is preferably 1% by weight to 50% by weight, more preferably 1% by weight to 30% by weight, based on the polyamic acid or its derivatives. %.

＜Oxazine compounds＞ For example, the liquid crystal alignment agent of the present invention may further contain an oxazine compound for the purpose of stabilizing the electrical characteristics of a liquid crystal display element over a long period of time. The oxazine compound may be one kind of compound, or two or more kinds of compounds. For the purpose, the content of the oxazine compound is preferably 0.1% by weight to 50% by weight, more preferably 1% by weight to 40% by weight, and still more preferably 1% by weight, based on the polyamic acid or its derivatives. ~20% by weight.

The oxazine compound is preferably an oxazine compound that is soluble in a solvent for dissolving polyamic acid or a derivative thereof and has ring-opening polymerizability. Preferable oxazine compounds include oxazine compounds represented by formula (OX-3-1), formula (OX-3-9), and formula (OX-3-10); and Japanese Patent Laid-Open No. 2007-286597 2013-242526, and the oxazine compound disclosed in Japanese Patent Application Laid-Open No. 2013-242526.

＜Oxazoline compounds＞ For example, the liquid crystal alignment agent of the present invention may further contain an oxazoline compound for the purpose of stabilizing the electrical characteristics of a liquid crystal display element over a long period of time. The oxazoline compound is a compound having an oxazoline structure. The oxazoline compound may be one kind of compound, or two or more kinds of compounds. For the above purpose, the content of the oxazoline compound is preferably 0.1% by weight to 50% by weight, more preferably 1% by weight to 40% by weight, and still more preferably 1% by weight relative to the polyamic acid or its derivatives. % to 20% by weight. Preferable oxazoline compounds include oxazoline compounds disclosed in JP-A-2010-054872 and JP-A-2013-242526. More preferably, 1,3-bis(4,5-dihydro-2-oxazolyl)benzene is mentioned.

＜Epoxy compound＞ For example, the liquid crystal alignment agent of the present invention may further contain an epoxy compound for the purpose of stabilizing the electrical characteristics of the liquid crystal display element over a long period of time, increasing the hardness of the film, or improving the adhesion with a sealant. The epoxy compound may be one kind of compound, or two or more kinds of compounds. For the above purpose, the content of the epoxy compound is preferably 0.1% by weight to 50% by weight, more preferably 1% by weight to 20% by weight, and still more preferably 1% by weight relative to the polyamic acid or its derivatives. ~10% by weight.

As the epoxy compound, various compounds having one or two or more epoxy rings in the molecule can be used. In order to achieve the purpose of increasing the hardness of the film or the purpose of improving the adhesion with the sealant, it is preferably a compound having two or more epoxy rings in the molecule, more preferably a compound having three or four epoxy rings .

Examples of the epoxy compound include epoxy compounds disclosed in JP-A-2009-175715, JP-A-2013-242526, JP-A-2016-170409, and International Publication No. 2017/217413. Examples of preferred epoxy compounds include: N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 3-glycidyloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, (3,3',4,4'- Diepoxy) bicyclohexyl, 1,4-butanediol glycidyl ether, tris(2,3-epoxypropyl) isocyanurate, 1,3-bis(N,N-diglycidyl) aminomethyl)cyclohexane or N,N,N',N'-tetraglycidyl-m-xylylenediamine. More preferably 3-glycidyloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane Ethoxysilane. In addition to this, an oligomer or polymer having an epoxy ring may also be added. As the oligomer or polymer having an epoxy ring, the oligomer or polymer disclosed in JP-A-2013-242526 can be used.

＜Silane compound＞ For example, the liquid crystal alignment agent of the present invention may further contain a silane compound for the purpose of improving the adhesiveness with the substrate and the sealant. For the purpose, the content of the silane compound is preferably 0.1% by weight to 30% by weight, more preferably 0.5% by weight to 20% by weight, and even more preferably 0.5% by weight to 10% by weight.

As the silane compound, silane coupling agents disclosed in JP-A-2013-242526, JP-A-2015-212807, JP-A-2018-173545, and International Publication No. 2018/181566 can be used. As a preferred silane coupling agent, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl Trimethoxysilane, p-Aminophenyltrimethoxysilane, 3-Aminopropyltriethoxysilane, 3-Glycidoxypropylmethyldiethoxysilane, 3-Isocyanatopropyltriethoxysilane Oxysilane or 3-ureidopropyltriethoxysilane.

In addition to the additives described above, for the purpose of increasing the strength of the alignment film or stabilizing the electrical characteristics of the liquid crystal display element for a long time, a compound having a cyclic carbonate group, a compound having a hydroxyalkylamide moiety or Hydroxyl compounds. Specific compounds include compounds disclosed in JP-A No. 2016-118753 and International Publication No. 2017/110976. As a preferable compound, following formula (HD-1) - a formula (HD-4) are mentioned. The content of these compounds is preferably 0.5% by weight to 50% by weight, more preferably 1% by weight to 30% by weight, and still more preferably 1% by weight to 10% by weight, based on the polyamic acid or its derivatives.

In addition, an antistatic agent can also be used when antistatic needs to be improved, and an imidization catalyst can also be used when imidization is performed at a low temperature. Examples of the imidization catalyst include those disclosed in JP-A-2013-242526.

＜Liquid crystal alignment film＞ Next, the liquid crystal alignment film of the present invention will be described. The liquid crystal alignment film of the present invention is formed by using the liquid crystal alignment agent of the present invention. When the liquid crystal alignment agent of the present invention is used to form the liquid crystal alignment film during heating and firing, an imidization reaction may be caused to form a polyimide-based liquid crystal alignment film. The liquid crystal alignment agent of the present invention is suitable for the liquid crystal alignment agent used for photo-alignment, and the photo-alignment method can be applied to the alignment treatment in the process of forming the liquid crystal alignment film.

Hereinafter, the formation method of the liquid crystal alignment film using the liquid crystal alignment agent for photo-alignment of this invention is demonstrated.

The liquid crystal alignment film of the present invention can be obtained by a common method of producing a liquid crystal alignment film from a liquid crystal alignment agent for photo-alignment. For example, the liquid crystal alignment film of the present invention can be obtained by going through the following steps: the step of forming the coating film of the liquid crystal alignment agent for photo-alignment of the present invention, the step of heating and drying the coating film to form a film of the liquid crystal alignment agent, A step of imparting anisotropy by irradiating the film of the liquid crystal alignment agent with light, and a step of heating and burning the anisotropic film of the liquid crystal alignment agent.

The coating film can be formed by applying the liquid crystal alignment agent of the present invention on a substrate in a liquid crystal display element in the same manner as the preparation of a normal liquid crystal alignment film. Substrates can include indium tin oxide (Indium Tin Oxide, ITO), indium zinc oxide ( _{In2O3 -} ZnO, IZO), indium gallium zinc oxide (In-Ga- _ZnO4 , IGZO) electrodes or color Substrates made of glass, silicon nitride, acrylic, polycarbonate, polyimide, etc., such as optical filters.

As a method of applying a liquid crystal alignment agent on a substrate, generally, a spinner method, a printing method, a dipping method, a dropping method, an inkjet method, and the like are known. These methods can also be similarly applied to the present invention.

As for the heat drying step, a method of heat-treating in an oven or an infrared furnace, a method of heat-treating on a hot plate, and the like are generally known. The heat-drying step is preferably carried out at a temperature within a range in which the solvent can evaporate, and more preferably carried out at a temperature relatively lower than the temperature in the heat-burning step. Specifically, the heat drying temperature is preferably in the range of 30°C to 150°C, more preferably in the range of 50°C to 120°C.

The heating and kneading step can be carried out under the conditions required for the imidization reaction of the polyamic acid or its derivatives. As for the firing of a coating film, a method of performing heat treatment in an oven or an infrared furnace, a method of performing heat treatment on a hot plate, and the like are generally known. These methods can also be similarly applied to the present invention. Usually, it is preferable to carry out at a temperature of about 90°C to 300°C for 1 minute to 3 hours, more preferably 120°C to 280°C, and still more preferably 150°C to 250°C.

When it is important to improve the anisotropy of the film or the afterimage characteristics when producing a liquid crystal display element, it is preferable to slowly increase the temperature of the heating step. Sub-heating and sintering, or heating by changing the temperature from low temperature to high temperature. In addition, two heating methods may be combined and performed.

When heating and firing multiple times at different temperatures, a plurality of heating devices set to different temperatures may be used, or one heating device may be used to sequentially change to different temperatures.

When multiple times of heating and sintering are carried out at different temperatures, it is preferably carried out at the initial sintering temperature of 90°C to 180°C, and preferably at the final temperature of 185°C to 300°C. For example, it is preferred to heat and burn at 220°C after heating at 110°C; heat and burn at 230°C after heating at 110°C; After heating at 150°C, heat at 200°C; after heating at 150°C, heat at 220°C; after heating at 150°C, heat at 230 ℃; or after heating and calcination at 170 ℃, heating and calcination at 200 ℃. Furthermore, it is also preferable to perform heating and kneading while gradually increasing the temperature in stages. In the case of heating and firing in two or more stages while changing the heating temperature, the heating time in each heating step is preferably 5 minutes to 30 minutes.

When performing kneading by changing the temperature from a low temperature to a high temperature, the initial temperature is preferably 90°C to 180°C. The final temperature is preferably 185°C to 300°C, more preferably 190°C to 230°C. The heating time is preferably 5 minutes to 60 minutes, more preferably 20 minutes to 60 minutes. The rate of temperature rise can be set to, for example, 0.5° C./min to 40° C./min. The rate of temperature increase during temperature increase may not be fixed.

In the method for forming the liquid crystal alignment film of the present invention, in order to align the liquid crystal in one direction with respect to the horizontal direction and/or the vertical direction, a known photoalignment method can be suitably used as a method for imparting anisotropy to the film.

The method for forming the liquid crystal alignment film of the present invention using the photo-alignment method will be described in detail. The liquid crystal alignment film of the present invention using the photo-alignment method can be formed by irradiating light to the film after heating and drying the coating film to impart anisotropy to the film, and heating the film. burn. Alternatively, it can be formed by heating and drying the coating film, heating and firing it, and then irradiating the thin film with light.

Furthermore, in order to improve the liquid crystal alignment ability of a liquid crystal alignment film, you may irradiate light, heating a coating film. Irradiation of light may be performed in the step of heating and drying the coating film or the step of heating and sintering, or may be performed between the heating and drying step and the heating and sintering step. For the heating temperature at the time of irradiating light in the step of heating and drying the coating film or the step of heating and sintering, refer to the description of the step of heating and drying or the step of heating and sintering. The heating temperature at the time of light irradiation between the heat drying step and the heat kneading step is preferably in the range of 30°C to 150°C, more preferably in the range of 50°C to 110°C.

As the light used in the photoirradiation step in the photoalignment method, for example, ultraviolet rays or visible light including light having a wavelength of 150 nm to 800 nm can be used. These lights are not particularly limited as long as they can impart liquid crystal alignment ability to the film, but polarized light is preferred, and linearly polarized light is more preferred when a strong alignment-regulating force is to be exhibited on the liquid crystal.

The irradiation amount of polarized light in the light irradiation step is preferably 0.05 J/cm ² to 10 J/cm ² , more preferably 0.1 J/cm ² to 5 J/cm ² . In addition, the wavelength of polarized light is preferably appropriately changed according to the compound having a photoreactive structure. When using the compound represented by formula (2), the wavelength of polarized light is preferably 200 nm to 400 nm, more preferably 300 nm to 400 nm. When using the compound represented by formula (3), the wavelength of polarized light is preferably 150 nm to 350 nm, more preferably 200 nm to 300 nm. The irradiation angle of the polarized light on the film surface is not particularly limited, but it is preferably as perpendicular as possible to the film surface from the viewpoint of shortening the alignment treatment time when a strong alignment restriction force on the liquid crystal is to be exhibited. In addition, the liquid crystal alignment film of the present invention can align liquid crystals in a direction at right angles to the polarization direction of linearly polarized light by irradiating linearly polarized light.

Among the light sources used in the step of irradiating light, ultrahigh-pressure mercury lamps, high-pressure mercury lamps, low-pressure mercury lamps, deep ultraviolet (Deep UV) lamps, halogen lamps, metal halide lamps, high-power metal halide lamps, Xenon lamp, mercury xenon lamp, excimer lamp, KrF excimer laser, fluorescent lamp, light emitting diode (LED) lamp, sodium lamp, microwave discharged electrodeless lamp, etc.

The liquid crystal alignment film of the present invention can be suitably obtained by a method further including steps other than the above steps.

Although the liquid crystal alignment film of the present invention does not require the step of cleaning the film after burning or light irradiation with a cleaning solution, a cleaning step may be provided according to other steps. Examples of the cleaning method using a cleaning liquid include brushing, jet spray, steam cleaning, ultrasonic cleaning, and the like. These methods can be used alone or in combination. As a cleaning solution, pure water; or various alcohols such as methanol, ethanol, and isopropanol; aromatic hydrocarbons such as benzene, toluene, and xylene; halogen-based solvents such as methylene chloride; acetone, methyl ethyl ketone, etc. and other ketones, but are not limited to these. Of course, as these washing liquids, sufficiently purified washing liquids with few impurities can be used. This cleaning method can also be applied to the cleaning step in the formation of the liquid crystal alignment film of the present invention.

In order to improve the liquid crystal alignment ability of the liquid crystal alignment film of the present invention, annealing treatment using heat or light may be used before and after the heating and burning step or before and after polarized or non-polarized light irradiation. In the annealing treatment, the annealing temperature is 30° C. to 180° C., preferably 50° C. to 150° C., and the annealing time is preferably 1 minute to 2 hours. In addition, examples of the annealing light used in the annealing treatment include UV lamps, fluorescent lamps, and LED lamps. The amount of light irradiation is preferably 0.3 J/cm ² to 10 J/cm ² .

The film thickness of the liquid crystal alignment film of the present invention is not particularly limited, but is preferably 10 nm to 300 nm, more preferably 30 nm to 150 nm. The film thickness of the liquid crystal alignment film of the present invention can be measured by a known film thickness measuring device such as a profiler or an ellipsometer.

The liquid crystal alignment film of the present invention is characterized by having particularly large alignment anisotropy. The size of such anisotropy can be evaluated by the method using polarized light IR as described in Unexamined-Japanese-Patent No. 2005-275364 etc. In addition, it can also be evaluated by using the method of ellipsometry (ellipsometry). Specifically, the retardation value of the liquid crystal alignment film can be measured by a spectroscopic ellipsometer. The retardation value of the film increases in proportion to the degree of alignment of the polymer backbone.

The liquid crystal alignment film of the present invention can be suitably used for alignment control of a liquid crystal composition in a liquid crystal display element. In addition to the alignment of the liquid crystal composition of the liquid crystal display element, it can also be used for the alignment control of the liquid crystal material in all other liquid crystal elements such as liquid crystal antennas, dimming windows, optical compensation materials, and variable phase shifters. In addition, the liquid crystal alignment film of the present invention has large anisotropy, so it can be used alone as an optical compensation material.

＜Liquid crystal display elements＞ Next, the liquid crystal display element of the present invention will be described. The liquid crystal display element of the present invention is characterized by having the liquid crystal alignment film of the present invention, and can realize high display quality due to its good contrast.

The liquid crystal display element of the present invention will be described in detail. In the present invention, in the following liquid crystal display element, the liquid crystal alignment film includes the liquid crystal alignment film of the present invention. The electrodes on one or both of them, the liquid crystal alignment film formed on the respective facing surfaces of the pair of substrates, the liquid crystal layer formed between the pair of substrates, and a pair of electrodes arranged to sandwich the facing substrates For polarizing film, backlight and driving device.

The electrodes are not particularly limited as long as they are formed on one surface of the substrate. Such an electrode includes, for example, ITO or a metal vapor-deposited film. In addition, the electrodes may be formed on the entire surface of one of the substrates, or may be formed in a patterned desired shape, for example. The desired shape of the electrode includes, for example, a comb shape or a zigzag structure. The electrodes can be formed on one of the pair of substrates, or on both substrates. The form of electrode formation differs depending on the type of liquid crystal display element. For example, in the case of an IPS type liquid crystal display element (transverse electric field type liquid crystal display element), the electrode is arranged on one of the pair of substrates, and on the other liquid crystal display element. In the case of a display element, electrodes are arranged on both of the pair of substrates. The liquid crystal alignment film is formed on the substrate or the electrode.

In the case of a parallel-aligned liquid crystal display element (for example, IPS, FFS, etc.), as a structure, from the backlight side, there are at least a backlight, a first polarizing film, a first substrate, a first liquid crystal alignment film, a liquid crystal layer, a second A substrate, a second polarizing film, the polarizing axis of the polarizing film is set in such a way that the polarizing axis of the first polarizing film (direction of polarized light absorption) and the second polarizing film are crossed (preferably orthogonal). In this case, the polarizing axis of the first polarizing film may be arranged parallel to or perpendicular to the alignment direction of the liquid crystal. A liquid crystal display element in which the polarizing axis of the first polarizing film is parallel to the liquid crystal alignment direction is called O-mode, and a liquid crystal display element in which the polarization axis is arranged perpendicularly is called E-mode. The liquid crystal alignment film of the present invention can also be applied to either O-mode or E-mode, which can be selected according to the purpose.

Compounds having dichroism can be used among a large number of photoisomerization-type materials. Therefore, when the polarization axis of the polarized light irradiated in order to add anisotropy to the liquid crystal alignment agent is parallel to and consistent with the polarization axis of the polarized light from the polarizing film disposed on the backlight side (in the case of using the liquid crystal alignment agent of the present invention , as the O-mode configuration), the transmittance of the liquid crystal alignment film in the light absorption wavelength region increases. Therefore, the transmittance of the liquid crystal display element can be further improved.

The liquid crystal layer is formed in such a manner that the liquid crystal composition is sandwiched between the pair of substrates on which the faces on which the liquid crystal alignment film is formed face each other. In the formation of the liquid crystal layer, a spacer that exists between the pair of substrates and forms an appropriate interval may be used, if necessary, such as fine particles or a resin sheet.

As a method for forming a liquid crystal layer, a vacuum injection method and a liquid crystal drop filling (One Drop Fill, ODF) method are known.

In the vacuum injection method, a gap (cell gap) is provided so that the liquid crystal alignment film faces face each other, and a sealant is printed to bond the substrate while leaving an injection port for liquid crystal. Liquid crystal is injected into the cell gap divided by the surface of the substrate and the sealant using vacuum differential pressure, and then the injection port is closed to manufacture a liquid crystal display element.

In the ODF method, a sealant is printed on the outer periphery of the liquid crystal alignment film surface of one of a pair of substrates, liquid crystal is dropped on the inner area of the sealant, and the other substrate is bonded so that the liquid crystal alignment film faces face each other. Then, the liquid crystal is press-spread over the entire surface of the substrate, and then, the entire surface of the substrate is irradiated with ultraviolet light to harden the sealant, thereby manufacturing a liquid crystal display element.

As for the sealant used for bonding the substrates, a thermosetting type is known in addition to a UV-curable type. Printing of the sealant can be performed, for example, by screen printing.

The liquid crystal composition is not particularly limited, and various liquid crystal compositions having positive or negative dielectric anisotropy can be used. Preferred liquid crystal compositions with positive dielectric anisotropy include: Japanese Patent 3086228, Japanese Patent 2635435, Japanese Patent Kokai Hei 5-501735, Japanese Patent Kokai Hei 8-157826, Japanese Patent Kokai Hei 8-231960, Japanese Patent Kokai Hei 8-231960, Japanese Patent Laid-Open No. 9-241644 (EP885272A1), Japanese Patent No. 9-302346 (EP806466A1), Japanese Patent No. 8-199168 (EP722998A1), Japanese Patent No. 9-235552, Japanese Patent No. 9-255956, Japanese Patent Japanese Patent Laid-Open No. 9-241643 (EP885271A1), Japanese Patent No. 10-204016 (EP844229A1), Japanese Patent No. 10-204436, Japanese Patent No. 10-231482, Japanese Patent No. 2000-087040, Japanese Patent No. 2001- 48822 et al. disclosed in the liquid crystal composition.

Preferred examples of the liquid crystal composition having negative dielectric anisotropy include: Japanese Patent Laid-Open No. 57-114532, Japanese Patent Laid-Open Hei 2-4725, Japanese Patent Laid-Open No. 4-224885, Japanese Patent Laid-Open No. JP-A-8-40953, JP-A-8-104869, JP-A-10-168076, JP-A-10-168453, JP-A-10-236989, JP-A-10-236990, JP-A-10 -236992, Japanese Patent Laid-Open No. 10-236993, Japanese Patent No. 10-236994, Japanese Patent No. 10-237000, Japanese Patent No. 10-237004, Japanese Patent No. 10-237024, Japanese Patent No. 10-237035 , Japanese Patent Kokai Hei 10-237075, Japanese Patent Kokai Hei 10-237076, Japanese Patent Kokai Hei 10-237448 (EP967261A1), Japanese Patent Kokai Hei 10-287874, Japanese Patent Kokai Hei 10-287875, Japanese Patent Kokai Hei 10- 291945, Japanese Patent Laid-Open 11-029581, Japanese Patent Laid-Open 11-080049, Japanese Patent Laid-Open 2000-256307, Japanese Patent Laid-Open 2001-019965, Japanese Patent Laid-Open 2001-072626, Japanese Patent Laid-Open 2001-192657, Liquid crystal combination disclosed in Japanese Patent Laid-Open 2010-037428, International Publication 2011/024666, International Publication 2010/072370, Japanese Patent Laid-Open 2010-537010, Japanese Patent Laid-Open 2012-077201, Japanese Patent Laid-Open 2009-084362, etc. thing.

Even if one or more optically active compounds are added to a liquid crystal composition having positive or negative dielectric anisotropy and used, there is no influence at all.

Moreover, for example, the liquid crystal composition used for the liquid crystal display element of this invention may further add an additive from a viewpoint of improving alignment, for example. Such additives are photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, pigments, defoamers, polymerization initiators, polymerization inhibitors, and the like. Preferable photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, pigments, antifoaming agents, polymerization initiators, and polymerization inhibitors include compounds disclosed in International Publication No. 2015/146330 and the like.

In order to be suitable for a liquid crystal display device in a polymer sustained alignment (PSA) mode, a polymerizable compound may be mixed in the liquid crystal composition. Preferred examples of polymerizable compounds include acrylates, methacrylates, vinyl compounds, vinyloxy compounds, propenyl ethers, epoxy compounds (oxirane, oxetane), vinyl ketones, etc. Compounds capable of polymerizing groups. Preferable compounds include compounds disclosed in International Publication No. 2015/146330 and the like. [Example]

Hereinafter, the present invention will be described with examples. In addition, the evaluation methods and compounds used in the examples are as follows.

Weight average molecular weight (Mw) The weight average molecular weight of polyamic acid was calculated|required by the GPC method using the 2695 separation module 2414 differential refractometer (made by Waters), and performing polystyrene conversion. Using a phosphoric acid-dimethylformamide (Dimethyl Formamide, DMF) mixed solution (phosphoric acid/DMF=0.6/100: weight ratio), the obtained polyamide was adjusted so that the polyamic acid concentration became about 2% by weight. acid to dilute. HSPgel RT MB-M (manufactured by Waters) was used as a column, and the mixed solution was used as a developing solvent, and the measurement was performed under conditions of a column temperature of 50° C. and a flow rate of 0.40 mL/min. As the standard polystyrene, TSK standard polystyrene manufactured by Tosoh Co., Ltd. was used.

＜Tetracarboxylic dianhydride＞

＜Diamine＞

<Solvent> NMP: N-methyl-2-pyrrolidone BC: Butyl cellosolve (ethylene glycol monobutyl ether) ＜Additives＞ Additive 1: 1,3-bis(4,5-dihydro-2-oxazolyl)benzene Additive 2: (3,3',4,4'-diepoxy)bicyclohexyl

The compound represented by formula (1-1) was obtained by referring to the method described in International Publication No. 2019/172460.

The compound represented by formula (1-2) was obtained by referring to the method described in International Publication No. 2018/147373.

The compound represented by the formula (3-4-1) is a compound in which the two esters on the cyclopropane ring in the formula (3-4) are trans-configured. The compound represented by formula (3-4-1) is obtained by the following method. After cooling the ethanol (100 mL) solution of trans (trans)-1,2-cyclopropanedicarboxylate (10.0 g, 53.7 mmol) in an ice bath, add sodium hydroxide (8.60 g, 215 mmol) water (100 mL) solution. After slowly warming the mixture to room temperature over 1 hour, the mixture was stirred for 15 hours. After the reaction, the reaction mixture was concentrated under reduced pressure, and ethanol was distilled off. The residue was cooled in an ice bath again, concentrated hydrochloric acid (20 mL) was added, and excess salt was added, and ethyl acetate (100 mL×8 times) was used for extraction. The organic layer was dried over anhydrous sodium sulfate, and then concentrated under reduced pressure to obtain a white solid of trans-1,2-cyclopropanedicarboxylic acid (yield: 6.44 g, yield: 92%). ¹ H-NMR (400 MHz, dimethyl sulfoxide (DMSO)-d ₆ ): δ 1.89-1.77 (m, 2H), 1.26-1.14 (m, 2H).

Thionyl chloride (30 mL) was added to trans-1,2-cyclopropanedicarboxylic acid (6.00 g, 46.1 mmol), stirred at 70°C for 4 hours, and then concentrated under reduced pressure to obtain thionyl chloride Chlorine was distilled off, whereby crude trans-1,2-cyclopropanedicarboxylic acid chloride was obtained. The carboxylic acid chloride was made into tetrahydrofuran (Tetrahydrofuran, THF) (90 mL) solution, and all of them were used in the following reaction. Under an argon atmosphere, triethylamine (16.3 g, 161 mmol) was added to a solution of 4-nitrophenol (13.5 g, 96.8 mmol) in THF (100 mL), and cooled in an ice bath. While vigorously stirring the mixture, a THF solution of the prepared carboxylic acid chloride was added over 5 minutes, then allowed to warm to room temperature and stirred at room temperature for 2.5 hours. Saturated ammonium chloride aqueous solution (100 mL) was added to the reaction mixture, and concentrated under reduced pressure. The residue was extracted with ethyl acetate (300 mL×3 times), and then washed with saturated sodium bicarbonate (300 mL). The organic layer was dried over anhydrous sodium sulfate and then concentrated under reduced pressure to obtain trans-1,2-cyclopropanedicarboxylate bis(4-nitrophenyl) ester as a pale yellow solid (7.36 g) . Furthermore, the solid remaining in the water layer was collected by filtration and washed with water to recover trans-1,2-cyclopropanedicarboxylate bis(4-nitrophenyl) ester as a pale yellow solid (6.72 g) , combined with the 7.36 g, thus obtaining dinitro compound 1 (trans-1,2-cyclopropanedicarboxylate bis(4-nitrophenyl) ester) (total yield 14.1 g, yield 82%) . ¹ H-NMR (400 MHz, CDCl ₃ ): δ 8.31 (d, J=9.2 Hz, 4H), 7.35 (d, J=9.2 Hz, 4H), 2.66-2.59 (m, 2H), 1.86-1.78 ( m, 2H).

Under an argon atmosphere, add tin(II) chloride dihydrate (84.8 g, 376 mmol) to a solution of dinitro compound 1 (14.0 g, 37.6 mmol) in ethyl acetate (370 mL), heat under reflux Stirring was continued for 4 hours. After the reaction, the reaction mixture was cooled to room temperature, and the reaction mixture was added to saturated aqueous sodium bicarbonate (1 L), and then extracted with ethyl acetate (300 mL×3 times). The obtained organic layer was successively washed with saturated aqueous sodium bicarbonate (300 mL) and saturated brine (300 mL), dried with anhydrous sodium sulfate, and concentrated under reduced pressure. Using a mixed solvent of chloroform: methanol as an eluent, while changing the ratio in the range of 100:0 to 95:5, the obtained residue was purified by silica gel column chromatography to obtain the target 2 White solid of amine compound (3-4-1) (yield 8.50 g, yield 72%). Due to the existence of enantiomers (Enantiomers) in the trans-1,2-cyclopropanedicarboxylate diethyl ester of the starting material, it is speculated that the material obtained in the described manner is actually represented by the formula (3-4-1). A mixture of the indicated compound and its enantiomer was used without isolating the two in this example. ¹ H-NMR (400 MHz, CDCl ₃ ): δ 6.90 (d, J=8.8 Hz, 4H), 6.67 (d, J=8.8 Hz, 4H), 3.64 (brs, 4H), 2.53-2.47 (m, 2H), 1.71-1.65 (m, 2H).

Preparation of varnish The varnish used in this example was prepared according to the following procedure. Here, varnish A1 to varnish A7 and varnish R1 to varnish R3 prepared in Production Example 1 to Production Example 10 of the varnish are polyamides obtained by reacting at least one compound having a photoreactive chemical structure as a raw material. acid solution. These varnishes express anisotropy in the film by irradiating polarized light of an appropriate wavelength after film formation. The blending varnish B1 to the blending varnish B3 prepared in Preparation Example 11 to Preparation Example 13 of the varnish are solutions of polyamic acid obtained without using a compound having a photoreactive chemical structure as a raw material, and are mixed with the varnish A1 - Varnish A7 or Varnish R1 - Varnish R3 were blended to prepare a blended liquid crystal alignment agent (alignment agent 7 to alignment agent 11, alignment agent 4 to comparison alignment agent 5 to be described later).

[Preparation Example 1 of Varnish] Preparation of Varnish A1 2.058 g of the compound represented by the formula (2-1-1) was placed in a 100 mL three-neck flask equipped with a stirring blade and a nitrogen inlet tube, and 34.0 g of N-methyl-2-pyrrolidone was added and stirred. 1.971 g of the compound represented by the formula (1-1) and 1.971 g of the compound represented by the formula (AN-4-17) (m=8) were added to the solution, and stirred at room temperature for 12 hours. Add 30.0 g of N-Methyl-2-pyrrolidone (N-Methyl-2-pyrrolidone, NMP) and 30.0 g of Butyl Cellosolve (BC), and heat and stir the solution at 60°C until Varnish A1 having a weight average molecular weight of a solute of about 13,400 and a resin content concentration (solid content concentration) of 6% by weight was obtained until the weight average molecular weight of the polymer as a solute became a desired weight average molecular weight.

[Preparation Example 2 to Preparation Example 13 of Varnish] Preparation of Varnish A2 to Varnish A7, Varnish R1 to Varnish R3, Varnish B1 to Varnish B3 Varnishes A2 to A7 with a solid content concentration of 6% by weight and a comparative varnish were prepared in the same manner as in Preparation Example 1 except that the compounds used as diamine and tetracarboxylic dianhydride were changed as shown in Table 1. R1 ~ varnish R3. As shown in Table 2, except having changed the compound used as a diamine and a tetracarboxylic dianhydride, it carried out similarly to the preparation example 1, and prepared varnish B1 - varnish B3. In varnish B1 - varnish B3, the conditions of heating and stirring were adjusted so that the weight average molecular weight of a polymer might be about 50,000. Table 1 and Table 2 show the weight average molecular weight of the produced polymer. In addition, in Table 1, regarding the preparation examples in which two or more compounds are described as diamines, it means that all the above-mentioned compounds are combined as diamines, and in the preparation examples in which two or more compounds are described as tetracarboxylic dianhydrides. The preparation example refers to combining all the above-mentioned compounds as tetracarboxylic dianhydride. The numerical values in the square brackets represent the compounding ratio (mol %), and the blank column means that the compound corresponding to the column is not used. In Table 2, the same is true.

[Table 1] Varnish preparation example Varnish No. Tetracarboxylic dianhydride diamine mw Preparation Example 1 A1 1-1 [50] AN-4-17 m=8 [50] 2-1-1 [100] 13,400 Preparation example 2 A2 1-2 [50] AN-4-17 m=8 [50] 2-1-1 [100] 12,500 Preparation example 3 A3 1-1 [25] AN-2-1 [25] AN-4-17 m=8 [50] 2-1-1 [70] 2-1-2 [30] 14,000 Preparation Example 4 A4 1-1 [20] 1-2 [30] AN-4-17 m=8 [50] 2-1-1 [80] 2-1-2 [20] 13,700 Preparation Example 5 A5 AN-1-1 [20] 1-1 [35] AN-4-17 m=8 [45] 2-1-1 [40] 2-1-2 [60] 12,100 Preparation example 6 A6 1-1 [40] AN-2-1 [20] AN-4-17 m=8 [40] 2-1-1 [100] 12,200 Preparation Example 7 A7 1-1 [15] 1-2 [15] AN-4-5 [70] 3-4-1 [100] 15,000 Preparation example 8 R1 AN-2-1 [50] AN-4-17 m=8 [50] 2-1-1 [100] 13,300 Preparation Example 9 R2 AN-2-1 [50] AN-4-17 m=8 [50] 2-1-1 [40] 2-1-2 [60] 13,700 Preparation Example 10 R3 AN-4-5 [100] 3-4-1 [100] 13,500

[Table 2] Varnish preparation example Varnish No. Tetracarboxylic dianhydride diamine Weight average molecular weight Preparation Example 11 B1 AN-3-2 [30] AN-1-1 [70] DI-13-1 [20] DI-4-1 [50] DI-5-9 [30] 52,000 Preparation Example 12 B2 AN-3-2 [40] AN-1-1 [60] DI-13-1 [30] DI-4-19 [50] DI-4-1 [20] 53,000 Preparation Example 13 B3 AN-3-2 [50] AN-1-1 [50] DI-13-1 [50] DI-4-1 [50] 55,000

[Example 1] Alignment agent 1 was prepared by diluting and stirring varnish A1 with an NMP/BC mixed solution (NMP/BC=7/3 weight ratio) so that the solid content concentration became 4% by weight. The prepared liquid crystal alignment agent was coated on a glass substrate with FFS electrodes and a glass substrate with a column spacer by a spinner method. After coating, heat the substrate at 60°C for 80 seconds to evaporate the solvent, and then use Multi-Light ML-501C/B manufactured by Ushio Electric Co., Ltd., from the vertical direction relative to the substrate Linearly polarized ultraviolet light is irradiated through a polarizing plate in the polarization wavelength range of 300 nm to 450 nm and a short-wavelength cut-off filter with a cut-on wavelength of 280 nm. The exposure energy at this time was measured using an ultraviolet integrated light meter UIT-150 (photoreceiver: UVD-S365) manufactured by Ushio Electric Co., Ltd., so that it became a "standard exposure amount" of 2.0±0.1 J at a wavelength of 365 nm. /cm ² to adjust the exposure time. Thereafter, a sintering treatment is performed at 220° C. for 30 minutes to form an alignment film with a film thickness of about 100 nm. Then, the two substrates on which the alignment films were formed were bonded together so that the surfaces on which the liquid crystal alignment films were formed faced each other and gaps for injecting the liquid crystal composition were provided between the facing liquid crystal alignment films. At this time, the polarization direction of the linearly polarized light irradiated to each liquid crystal alignment film was made parallel. The positive liquid crystal composition A was injected into these cells to produce a liquid crystal cell (liquid crystal display element) having a cell thickness of 5 μm. The luminance-voltage characteristics (BV characteristics) of the produced liquid crystal cell were measured, and the contrast ratio (Contrast Ratio, CR) was obtained using the ratio of the minimum luminance to the maximum luminance. The larger the value of CR, the clearer the bright and dark display, and the better the contrast. CR=B _max /B _min In the formula, B _max represents the maximum brightness in the BV characteristic, and B _min represents the minimum brightness in the BV characteristic. Contrast ratio (CR) was evaluated according to the following criteria. CR is 3000 or more: 〇CR is less than 3000: × Next, the exposure time is adjusted so that the amount of linearly polarized light becomes "low exposure" 0.8 ± 0.1 J/cm ² which is lower than the standard exposure amount. Otherwise, A liquid crystal cell was produced in exactly the same manner, and the contrast ratio was obtained in the same manner. If the contrast is good at both the standard exposure amount and the low exposure amount, it means that the range of suitable polarized light irradiation energy in liquid crystal display element manufacture is wider, and it means that it is more preferable as a liquid crystal alignment agent for photoalignment. In addition, the evaluation results of the contrast of Examples 1 to 11 and Comparative Examples 1 to 5 are described in Table 3 and Table 4 together with the preparation conditions of the varnish.

[Example 2] Alignment agent 2 was prepared in the same manner as in Example 1, except that varnish A2 was used instead of varnish A1, and additive 1 was added so as to be 5 parts by weight relative to the solid content while adding the NMP/BC mixed solution. About the alignment agent 2, the liquid crystal cell was produced similarly to Example 1, and the measurement and evaluation of contrast were performed.

[Example 3-Example 5, Comparative Example 1-Comparative Example 2] Alignment agents 3 to 5 and comparison alignment agents 1 to 2 were prepared in the same manner as in Example 1 except that the varnishes shown in Table 3 were used instead of the varnish A1. Regarding alignment agents 3 to 5 and comparative alignment agents 1 to 2, liquid crystal cells were produced in the same manner as in Example 1, and the contrast was measured and evaluated.

EXAMPLE 6, COMPARATIVE EXAMPLE 3 Alignment agent 6 and comparative alignment agent 3 were prepared similarly to Example 1 except having used the varnish shown in Table 3 instead of varnish A1. Alignment agent 6 and comparative alignment agent 3 were irradiated with linearly polarized light of ultraviolet rays from a direction perpendicular to the substrate through a polarizer in the polarization wavelength range of 230 nm to 310 nm. For exposure energy, Ushio Electric Co., Ltd. was used. Measure the amount of light with an ultraviolet integrated light meter UIT-150 (photoreceiver: UVD-S254), and adjust the exposure time of linearly polarized light so that it becomes the "standard exposure amount" 0.5±0.1 J/ ^cm2 at a wavelength of 254 nm. Except that, the liquid crystal cell was produced similarly to Example 1, and the measurement and evaluation of contrast were performed. Next, except that the exposure time was adjusted so that the amount of linearly polarized light became "low exposure" 0.2 ± 0.1 J/cm ² lower than the standard exposure amount, a liquid crystal cell was produced in exactly the same way, and the contrast.

[Example 7] Varnish A1 and varnish B1 were blended at a weight ratio of 3:7 to obtain a blended varnish with a solid content concentration of 6% by weight. Furthermore, it diluted and stirred with the NMP/BC mixed solution (NMP/BC=7/3 weight ratio) so that the solid content concentration might become 4 weight%, and the alignment agent 7 was prepared. Except having replaced the alignment agent 1 with the alignment agent 7, it carried out similarly to Example 1, and produced the liquid crystal cell, and performed the measurement and evaluation of contrast.

[Example 8] Alignment agent 8 was prepared in the same manner as in Example 7, except that varnish A3 was used instead of varnish A1, and additive 2 was added so as to be 5 parts by weight relative to the solid content while adding the NMP/BC mixed solution. Regarding the alignment agent 8, a liquid crystal cell was produced in the same manner as in Example 1, and the contrast was measured and evaluated.

[Example 9 to Example 10, Comparative Example 4] Alignment agents 9 to 10 were prepared in the same manner as in Example 7 except that the varnish shown in Table 4 was used instead of varnish A1 and varnish B1, and the blending ratio was changed to the blending ratio shown in Table 4. Alignment agent 4. For example, in Example 9 in Table 4, it means that varnish A4 and varnish B2 for blending were blended at the weight ratio of 4:6 that a blending ratio is "4:6". Regarding the alignment agents 9 to 10 and the comparative alignment agent 4, liquid crystal cells were produced in the same manner as in Example 1, and the contrast was measured and evaluated.

[Example 11, Comparative Example 5] Alignment agent 11 and comparative alignment agent 5 were prepared in the same manner as in Example 7, except that the varnish shown in Table 4 was used instead of varnish A1 and varnish B1, and the blending ratio was changed to the blending ratio shown in Table 4. . Regarding the alignment agent 11 and the comparison alignment agent 5, liquid crystal cells were produced in the same manner as in Example 6, and the contrast was measured and evaluated.

（物性值） 相轉變溫度NI：100.1℃、介電各向異性Δε：5.1、折射率各向異性Δn：0.093、粘度η：25.6 mPa·s. <Positive type liquid crystal composition A>

(Physical properties) Phase transition temperature NI: 100.1°C, dielectric anisotropy Δε: 5.1, refractive index anisotropy Δn: 0.093, viscosity η: 25.6 mPa·s.

[table 3] Alignment agent No. Varnish No. additive Amount added (parts by weight) Exposure wavelength contrast standard exposure low exposure Example 1 Alignment agent 1 A1 365 nm ○ ○ Example 2 Alignment agent 2 A2 1 5 365 nm ○ ○ Example 3 Alignment agent 3 A3 365 nm ○ ○ Example 4 Alignment agent 4 A4 365 nm ○ ○ Example 5 Alignment agent 5 A6 365 nm ○ ○ Example 6 Alignment agent 6 A7 254 nm ○ ○ Comparative example 1 Compare Alignment Agent 1 R1 365 nm ○ x Comparative example 2 Compare Alignment Agent 2 R2 365 nm ○ x Comparative example 3 Compare Alignment Agent 3 R3 254 nm ○ x

[Table 4] Alignment agent No. Varnish No. Blending varnish No. Blending ratio additive Amount added (parts by weight) Exposure wavelength contrast standard exposure low exposure Example 7 Alignment agent 7 A1 B1 3:7 365 nm ○ ○ Example 8 Alignment agent 8 A3 B1 3:7 2 5 365 nm ○ ○ Example 9 Alignment agent 9 A4 B2 4:6 365 nm ○ ○ Example 10 Alignment agent 10 A6 B2 5:5 365 nm ○ ○ Example 11 Alignment agent 11 A7 B3 4:6 254 nm ○ ○ Comparative example 4 Compare Alignment Agent 4 R1 B2 4:6 365 nm ○ x Comparative Example 5 Compare Alignment Agent 5 R3 B3 3:7 254 nm ○ x

The contrast in Examples 1 to 11 was evaluated as "◯" in any of the liquid crystal cells produced by the standard exposure amount and the low exposure amount. It can be seen that the polymer obtained by polymerizing tetracarboxylic dianhydride represented by formula (1-1) or formula (1-2) with a compound having a photoreactive structure is used as a liquid crystal alignment agent for photoalignment, even if exposed to Even if the amount is small, an alignment film capable of realizing a high-contrast liquid crystal display element can be obtained. [industrial availability]

If the liquid crystal alignment agent for photo-alignment of this invention is used, even when the exposure energy of a photo-alignment process is small, the liquid crystal alignment film which realizes the high-contrast liquid crystal display element can be manufactured. The liquid crystal alignment agent for photo-alignment of the present invention can be suitably applied to transverse electric field type liquid crystal display elements.

Claims (10)

A liquid crystal alignment agent for photo-alignment, comprising at least one polymer and a solvent, and in the liquid crystal alignment agent for photo-alignment, at least one of the polymers is formed by reacting tetracarboxylic dianhydrides and diamines A polymer comprising formula (1-1) or formula (1-2) in a raw material composition used as a raw material of the polymer formed by reacting the tetracarboxylic dianhydrides with the diamine ) at least one of the compounds represented, and a compound having a photoreactive structure that imparts liquid crystal alignment to the alignment film by photoreaction;

. The liquid crystal alignment agent for photo-alignment according to Claim 1, wherein the photo-reaction is at least one of photo-isomerization, photo-Friesian rearrangement, photo-decomposition and photo-dimerization. The liquid crystal alignment agent for photo-alignment according to Claim 1 or Claim 2, wherein the compound having a photoreactive structure is at least one compound represented by formula (2);

In formula (2), X is an alkylene group with 1 to 12 carbons, and when the carbon number of the alkylene group is 2 or more, one or more non-adjacent -(CH ₂ ) ₂ -s can be passed through -O -or-NH-substituted, R ^a and R ^b are independently hydrogen atom, methyl, methoxy, trifluoromethyl, fluorine atom, methoxycarbonyl, or formula (P1-1) or formula (P1 -2) The monovalent group represented by R ^c is independently a hydrogen atom, methyl, methoxy, trifluoromethyl, fluorine atom, or represented by formula (P1-1) or formula (P1-2) The monovalent group, j is 0 or 1, and a~c are independently integers of 0~2,

In formula (P1-1) and formula (P1-2), R ^6a , R ^7a and R ^8a independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group , or a substituted or unsubstituted alkoxycarbonyl group, R ^6a , R ^7a and R ^8a may be the same as or different from each other, * represents the bonding position on the benzene ring in formula (2), formula (2 ), the group whose bonding position is not fixed to any carbon atom constituting the ring means that the bonding position on the ring is arbitrary. The liquid crystal alignment agent for photo-alignment according to claim 3, wherein the compound represented by the formula (2) is any one of the formula (2-1) to the formula (2-3);

In formula (2-1), R ^1a and R ^1c independently represent a hydrogen atom or a monovalent group represented by formula (P1-1) or formula (P1-2), in formula (2-2), R ^2a and R ^2b each independently represent a hydrogen atom or a monovalent group represented by formula (P1-1) or formula (P1-2), and R ^2c each independently represent a hydrogen atom, methyl, methoxy, or trifluoromethyl , a fluorine atom, X ₁ is an alkylene group with 1 to 12 carbons, and when the carbon number of the alkylene group is 2 or more, one or more non-adjacent -(CH ₂ ) ₂ -s can be passed through -O- or -NH-, k is an integer from 0 to 2, in formula (2-3), R ^3a each independently represents a hydrogen atom or a monovalent group represented by formula (P1-1) or formula (P1-2) , R ⁴ and R ⁵ are each independently a hydrogen atom or a fluorine atom, R ⁴ and R ⁵ do not become a hydrogen atom at the same time, R ^3c are each independently a hydrogen atom, methyl, methoxy, trifluoromethyl, fluorine atom, X ₁ is an alkylene group with 1 to 12 carbons, and when the carbon number of the alkylene group is 2 or more, one or more non-adjacent -(CH ₂ ) ₂ - of the alkylene group may be Substituted by -O- or -NH-, m is an integer from 0 to 2,

In formula (P1-1) and formula (P1-2), R ^6a , R ^7a and R ^8a independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group , or a substituted or unsubstituted alkoxycarbonyl group, R ^6a , R ^7a and R ^8a may be the same as or different from each other, and * is represented in formula (2-1), formula (2-2) or formula (2 -3) the bonding position on the benzene ring, in formula (2-1), formula (2-2) or formula (2-3), the bonding position is not fixed on any carbon atom constituting the ring The group means that the bonding position on the ring is arbitrary. The liquid crystal alignment agent for photo-alignment according to Claim 1 or Claim 2, wherein the compound having a photoreactive structure is at least one compound represented by formula (3);

In formula (3), R ¹ and R ² independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbons, a haloalkyl group with 1 to 6 carbons or an alkoxy group with 1 to 6 carbons, R ¹ and ^R2 can be integrated to form a substituted methylene group, and X each independently represent a halogen atom, an alkyl group with 1 to 6 carbons, a haloalkyl group with 1 to 6 carbons, or an alkane with 1 to 6 carbons Oxygen group, n independently represent the integer of 0-4. The liquid crystal alignment agent for photo-alignment according to Claim 1 or Claim 2 further contains additives. The liquid crystal alignment agent for photo-alignment according to Claim 6, wherein the additive is at least one selected from the group consisting of oxazoline compounds and epoxy compounds. A liquid crystal alignment film formed from the liquid crystal alignment agent for photo-alignment according to any one of claim 1 to claim 7. A liquid crystal element having the liquid crystal alignment film as described in Claim 8. A method for manufacturing a liquid crystal alignment film, comprising: a step of coating the liquid crystal alignment agent for photo-alignment according to any one of claim 1 to claim 7 on a substrate; and a step of irradiating polarized ultraviolet rays to the coating film.