TW202202603A - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

The present invention provides a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element. The liquid crystal alignment agent includes a polymer (A) and a solvent (B). The polymer (A) is manufactured by reacting a specific tetracarboxylic acid dianhydride component (a) with a specific diamine component (b). The liquid crystal alignment film is formed form the liquid crystal alignment agent, and the liquid crystal display element including the liquid crystal alignment film has a lower flicker level after the element is driven.

Description

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

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element, in particular to a liquid crystal display element with better flashing degree immediately after driving by using the liquid crystal alignment agent.

Liquid crystal display elements used for liquid crystal televisions, liquid crystal displays, etc. are usually provided with a liquid crystal alignment film for controlling the alignment state of liquid crystals inside the element. At present, the most common method in the industry is to rub cotton, nylon, polyester and other cloth materials on the electrode substrate in one direction, and it is formed of polyamide and/or polyimide which has been imidized. The surface of the film is subjected to a so-called rubbing treatment to obtain the liquid crystal alignment film.

During the alignment process of the liquid crystal alignment film, rubbing the film surface is an industrially easier method to produce. However, with the increasing demand for higher efficiency, higher precision, and larger size of liquid crystal display elements, during rubbing treatment, the surface of the alignment film is subject to damage, flying dust, mechanical force and electrostatic force. The resulting influence and various problems such as non-uniformity on the alignment treatment surface become more prominent.

As a method of replacing the rubbing treatment, a photo-alignment method using polarized ultraviolet irradiation to impart alignment energy to a liquid crystal is known. The so-called liquid crystal alignment treatment by photo-alignment method includes substances that utilize photoisomerization reaction, substances that utilize photocrosslinking reaction, and substances that utilize photolysis reaction in terms of reaction mechanism. In addition, Japanese Patent Laid-Open No. 9-297313 proposes that the photo-alignment method uses a polyimide film having an alicyclic structure such as cyclobutane in its main chain. When using polyimide as an alignment film for photo-alignment, because the heat resistance of the alignment film is higher than that of other types of alignment films, the applicability of this alignment film is optimistic.

The photo-alignment method is a non-friction alignment treatment method, which not only has the advantage of being able to be manufactured by a simple process in industry, but also has the advantages of lateral electric field effect technology (In-Plane-Switching; IPS) driving method and boundary electric field switching wide viewing angle technology ( In the liquid crystal display element of the Fringe Field Switching; FFS) driving method, compared with the liquid crystal alignment film obtained by the rubbing treatment method, the use of the liquid crystal alignment film obtained by the above-mentioned photo-alignment method is expected to improve the contrast and viewing angle characteristics of the liquid crystal display element. Therefore, the photo-alignment method is a promising and attracting liquid crystal alignment treatment method.

However, when the liquid crystal alignment film prepared by the photo-alignment method is applied to a liquid crystal display element, the obtained liquid crystal display element still has the problem of poor flicker immediately after driving, that is, the liquid crystal alignment film is irradiated after being irradiated. The accumulated charge of the obtained liquid crystal display element is slowly eliminated, resulting in excessively high residual charge, resulting in the problem of afterimage. As can be seen from the above, in order to meet the requirements of the current photo-alignment IPS type liquid crystal display manufacturers, it is the goal of those skilled in the art to provide a liquid crystal alignment agent that can form a liquid crystal display element with a better degree of flicker immediately after driving.

One aspect of the present invention is to provide a liquid crystal alignment agent comprising a polymer (A) and a solvent (B). The liquid crystal alignment agent can improve the degree of flicker immediately after the liquid crystal display element is driven. In addition, the liquid crystal aligning agent of the present invention may optionally contain an additive (C).

Another aspect of the present invention is to provide a liquid crystal alignment film formed by using the above-mentioned liquid crystal alignment agent.

Another aspect of the present invention is to provide a liquid crystal display element comprising the above-mentioned liquid crystal alignment film.

According to the above aspect of the present invention, a liquid crystal alignment agent is provided, and the liquid crystal alignment agent comprises a polymer (A) and a solvent (B), which are described below.

Polymer (A)

The polymer (A) of the present invention can be obtained by polymerizing the tetracarboxylic dianhydride component (a) and the diamine component (b).

A preferred specific example of the aforementioned polymer (A) may be a polyimide polymer, a polyimide polymer, a polyimide-based block copolymer or a combination thereof. Among them, preferred specific examples of polyimide-based block copolymers are polyimide block copolymers, polyimide block copolymers, polyimide-polyimide block copolymers polymers or any combination thereof.

Tetracarboxylic dianhydride component (a)

Tetracarboxylic dianhydride compound (a-1)

於式(I)中，R₁ 至R₄ 各自獨立地代表氫原子、鹵素原子、碳數為1至6的烷基、碳數為2至6的烯基、碳數為2至6的炔基、含有氟原子且碳數為1至6的一價有機基團或苯基，R₁ 至R₄ 為相同或不相同，且R₁ 、R₂ 、R₃ 及R₄ 之至少一者不為氫原子。The tetracarboxylic dianhydride component (a) of the present invention comprises at least one tetracarboxylic dianhydride compound (a-1) represented by the following formula (I):

In formula (I), R ₁ to R ₄ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, and an alkyne having 2 to 6 carbon atoms. group, a monovalent organic group containing a fluorine atom and having a carbon number of 1 to 6 or a phenyl group, R ₁ to R ₄ are the same or different, and at least one of R ₁ , R ₂ , R ₃ and R ₄ is not for the hydrogen atom.

When R ₁ , R ₂ , R ₃ and R ₄ have a steric barrier structure, the prepared liquid crystal aligning agent will make the formed liquid crystal display element have poor flicker immediately after driving. Therefore, R ₁ , R ₂ , R ₃ and R ₄ are preferably hydrogen atoms, methyl groups or ethyl groups, and among them, methyl groups are more preferred.

Specific examples of the tetracarboxylic dianhydride compound (a-1) represented by the formula (I) can be, for example, compounds represented by the following formulae (I-1) to (I-8). For the degree of flicker immediately after driving, formula (I-1) is preferred.

The above-mentioned tetracarboxylic dianhydride compound (a-1) may be used alone or in combination of two or more.

Based on the total usage amount of the tetracarboxylic dianhydride component (a) is 100 moles, the usage amount of the tetracarboxylic dianhydride compound (a-1) is 10 moles to 100 moles, preferably 20 moles to 100 moles 80 moles, and more preferably 30 moles to 70 moles.

If the tetracarboxylic dianhydride component (a) does not contain the tetracarboxylic dianhydride compound (a-1), the prepared liquid crystal alignment agent will make the formed liquid crystal display device have poor flicker immediately after driving.

Other tetracarboxylic dianhydride compounds (a-2)

The tetracarboxylic dianhydride component (a) of the present invention may optionally contain other tetracarboxylic dianhydride compounds (a-2). Preferred specific examples of other tetracarboxylic dianhydride compounds (a-2) are (1) aliphatic tetracarboxylic dianhydride compounds, (2) alicyclic tetracarboxylic dianhydride compounds, (3) aromatic tetracarboxylic acids An acid dianhydride compound or (4) a tetracarboxylic dianhydride compound represented by the following formulae (V-1) to (V-6), and the like.

The (1) aliphatic tetracarboxylic dianhydride compound of the present invention includes, but is not limited to, aliphatic tetracarboxylic dianhydride compounds such as ethane tetracarboxylic dianhydride or butane tetracarboxylic dianhydride.

(2) Alicyclic tetracarboxylic dianhydride compounds of the present invention include but are not limited to 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3, 4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4 -Cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentane Tetracarboxylic dianhydride, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyl tetracarboxylic dianhydride, cis-3,7-dibutyl cycloheptyl-1,5-diene-1,2,5,6-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride or bicyclo[2.2.2]-octane - Alicyclic tetracarboxylic dianhydride compounds such as 7-ene-2,3,5,6-tetracarboxylic dianhydride.

Specific examples of the (3) aromatic tetracarboxylic dianhydride compound of the present invention may include, but are not limited to, 3,4-dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic dianhydride, benzene homo Tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3' ,4,4'-biphenyltetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3'- 4,4'-diphenylethane tetracarboxylic dianhydride, 3,3',4,4'-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3',4,4'-tetra Phenylsilane tetracarboxylic dianhydride, 1,2,3,4-furan tetracarboxylic dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4, 4'-diphenyl ether tetracarboxylic dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, 2,3,3',4'-diphenyl sulfide Tetracarboxylic dianhydride, 3,3',4,4'-diphenyl sulfide tetracarboxylic dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylene dianhydride, 4 ,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, 3,3',4,4'-perfluoroisopropylene diphthalic acid dianhydride, 2,2', 3,3'-diphenyltetracarboxylic dianhydride, 2,3,3',4'-diphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride Anhydride, bis(phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis(triphenylphthalic acid) dianhydride, m-phenylene-bis(triphenylphthalic acid) dianhydride , bis(triphenylphthalic acid)-4,4'-diphenyl ether dianhydride, bis(triphenylphthalic acid)-4,4'-diphenylmethane dianhydride, ethylene glycol-bis (anhydro trimellitate), propylene glycol-bis (anhydro trimellitate), 1,4-butanediol-bis (anhydro trimellitate), 1,6-hexanediol-bis (anhydro trimellitate) trimellitate), 1,8-octanediol-bis(anhydrotrimellitate), 2,2-bis(4-hydroxyphenyl)propane-bis(anhydrotrimellitate), 2 ,3,4,5-tetrahydrofuran tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxy-3-furyl)- Naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5-methyl-5-(tetrahydro-2,5-dione pendant oxy-3-furyl)-naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5-ethyl-5 -(Tetrahydro-2,5-dioxy-3-furyl)-naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b - Hexahydro-7-methyl-5-(tetrahydro-2,5-dioxy-3-furyl)-naphtho[1,2-c]-furan-1,3-dione, 1 ,3,3a,4,5,9b-hexahydro-7-ethyl-5-(tetrahydro-2,5-dioxy-3-furyl)-naphtho[1,2-c]- furfur Furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxy-3-furyl)- Naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-ethyl-5-(tetrahydro-2,5-dione pendant oxy-3-furyl)-naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5,8-dimethyl Alkyl-5-(tetrahydro-2,5-dioxy-3-furyl)-naphtho[1,2-c]-furan-1,3-dione, 5-(2,5-dione pendant oxytetrahydrofuranyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid dianhydride, etc.

(V-1)

(V-2)

(V-3)

(V-4)

(V-5)

(V-6)According to (4) of the present invention, the tetracarboxylic dianhydride compounds represented by formula (V-1) to formula (V-6) are described in detail as follows:

(V-1)

(V-2)

(V-3)

(V-4)

(V-5)

(V-6)

(V-5-1)

(V-5-2)

(V-5-3)In formula (V-5), N ₁ represents a divalent group containing an aromatic ring; r represents an integer of 1 to 2; N ₂ and N ₃ may be the same or different, and may respectively represent a hydrogen atom or an alkyl group. Preferably, the tetracarboxylic dianhydride compound represented by the formula (V-5) can be selected from the compounds represented by the following formulae (V-5-1) to (V-5-3).

(V-5-1)

(V-5-2)

(V-5-3)

(V-6-1)In formula (V-6), N ₄ represents a divalent group containing an aromatic ring; N ₅ and N ₆ may be the same or different, and represent a hydrogen atom or an alkyl group, respectively. Preferably, the tetracarboxylic dianhydride compound represented by the formula (V-6) can be selected from the compounds represented by the following formula (V-6-1).

(V-6-1)

The above-mentioned other tetracarboxylic dianhydride compound (a-2) can be used individually by 1 type or in mixture of several types.

Based on the total usage amount of the tetracarboxylic dianhydride component (a) is 100 moles, the usage amount of the other tetracarboxylic dianhydride compounds (a-2) is 0 moles to 90 moles, preferably 20 moles to 80 moles, and more preferably 30 to 70 moles.

The usage amount of the diamine component (b) is 100 moles, and the usage amount of the tetracarboxylic dianhydride component (a) is in the range of 20 moles to 200 moles, and preferably 30 moles to 120 moles .

Diamine component (b)

The diamine component (b) of the present invention may comprise a diamine compound (b-1) represented by the following formula (II).

In formula (II), M ₁ and M ₂ independently represent single bond, -O-, -S-, -NM ₃ -, ester group, amido group, thioester group, urea group, carbonate group or urethane group, wherein M ₃ represents a hydrogen atom or a methyl group, and M ₁ and M ₂ may be the same or different; A represents an alkylene group with a carbon number of 2 to 20; X ₁ and X ₂ independently represent Divalent organic groups represented by the following formulas (III-1) to (III-19), and X ₁ and X ₂ are selected from the two different ones from the formulas (III-1) to (III-19) structure, wherein at least one of X ₁ and X ₂ represents the structure shown in formula (III-17), formula (III-18) or formula (III-19).

In formula (III-2), X ₃ represents an alkylene group having 1 to 5 carbon atoms; in formula (III-14), X ₄ represents a hydrogen atom, a halogen atom, a methyl group, a hydroxyl group or a methoxy group; In formula (III-17), X ₅ and X ₆ each independently represent a halogen atom, a methyl group, a hydroxyl group or a methoxy group; in formula (III-18), X ₇ and X ₈ each independently represent a hydrogen atom , a halogen atom, a methyl group, a hydroxyl group or a methoxy group, and at least one of X ₇ and X ₈ is not a hydrogen atom.

It should be noted that the aforementioned X ₁ and X ₂ are selected from the two different structures in the formula (III-1) to the formula (III-19), which means that X ₁ and X ₂ have different main structures (that is, the formula (III)). -1) to the structure represented by formula (III-19)), not just the difference in functional groups. In other words, if X ₁ and X ₂ have the same main structure, and the two main structures have different functional groups, although their chemical structures have functional group differences, these diamine compounds do not belong to the present invention. Diamine compound (b-1). In formula (II), when X ₁ and X ₂ are selected from formula (III-1) to formula (III-19) with the same structural formula (that is, the same main structure, and the functional group bonded to the main structure) When it is the same or different), the prepared liquid crystal alignment agent will make the formed liquid crystal display element have a poor degree of flicker immediately after driving.

In formula (II), M ₁ and M ₂ are preferably a single bond, -O-, -S-, -NM ₃ -, ester group or amido group, respectively, and more preferably -O-. Next, from the viewpoint of liquid crystal alignment, A preferably represents an alkylene group having 2 to 6 carbon atoms, and more preferably an alkylene group having 2 to 4 carbon atoms.

In formula (III-2), X ₃ preferably represents an alkylene group having 1 to 3 carbon atoms, and in formula (III-14), X ₄ preferably represents a hydrogen atom or a methyl group.

In formula (II), if at least one of X ₁ and X ₂ does not represent the structure shown in formula (III-17), formula (III-18) or formula (III-19), the prepared The liquid crystal alignment agent will cause the formed liquid crystal display element to have a poor degree of flicker immediately after being driven.

於式(II-1-1)至式(II-1-3)中，A、M₁ 、M₂ 、X₅ 、X₆ 、X₇ 與X₈ 之定義分別如前所述。In some embodiments, the diamine compound (b-1) may be selected from the diamine compounds represented by the following formulae (II-1-1) to (II-1-3).

In formula (II-1-1) to formula (II-1-3), the definitions of A, M ₁ , M ₂ , X ₅ , X ₆ , X ₇ and X ₈ are as described above, respectively.

When the diamine compound (b-1) is selected from the diamine compounds represented by formula (II-1-1) to formula (II-1-3), the obtained liquid crystal alignment agent can further reduce the formation of The degree of flicker immediately after the liquid crystal display element is driven.

(II-2-1)

(II-2-2)

(II-2-3)

(II-2-4)

(II-2-5)

(II-2-6)

(II-2-7)

(II-2-8)

(II-2-9)

(II-2-10)

(II-2-11)

(II-2-12)

(II-2-13)

(II-2-14)

(II-2-15)

(II-2-16)

(II-2-17)

(II-2-18)

(II-2-19)

(II-2-20)

(II-2-21)

(II-2-22)

(II-2-23)

(II-2-24)

(II-2-25)

(II-2-26)

(II-2-27)

(II-2-28) 於式(II-2-16)與式(II-2-24)中，M₃ 之定義如前所述，在此不另贅述。Specific examples of the diamine compound (b-1) represented by the aforementioned formula (II) may include, but are not limited to, the diamine compounds represented by the following formulae (II-2-1) to (II-2-56).

(II-2-1)

(II-2-2)

(II-2-3)

(II-2-4)

(II-2-5)

(II-2-6)

(II-2-7)

(II-2-8)

(II-2-9)

(II-2-10)

(II-2-11)

(II-2-12)

(II-2-13)

(II-2-14)

(II-2-15)

(II-2-16)

(II-2-17)

(II-2-18)

(II-2-19)

(II-2-20)

(II-2-21)

(II-2-22)

(II-2-23)

(II-2-24)

(II-2-25)

(II-2-26)

(II-2-27)

(II-2-28) In formula (II-2-16) and formula (II-2-24), the definition of M ₃ is as described above, and it is not repeated here.

The above-mentioned diamine compound (b-1) may be used alone or in combination of two or more.

Based on the total usage amount of the diamine component (b) is 100 moles, the usage amount of the diamine compound (b-1) is 5 moles to 50 moles, preferably 5 moles to 40 moles, and more Preferably, it is 5 moles to 30 moles.

If the diamine component (b) does not contain the diamine compound (b-1), the obtained liquid crystal alignment agent will make the formed liquid crystal display element have a poor degree of flicker immediately after driving.

Diamine compound (b-2)

於式(IV)中，Z₁ 與Z₅ 分別獨立地代表單鍵、-CH₂ -或-CH₂ CH₂ -；Z₂ 與Z₄ 分別獨立地代表-CH₂ -或-CH₂ CH₂ -；Z₃ 代表碳數為1至6之伸烷基或伸環己基；Y₁ 與Y₂ 分別獨立地代表單鍵、-O-、-NH-、-N(CH₃ )-、-C(=O)-、-C(=O)O-、-C(=O)NH-、-C(=O)N(CH₃ )-、-OC(=O)-、-NHC(=O)-或N(CH₃ )C(=O)-；Y₃ 代表碳數為1至20之直鏈羥基、碳數為3至20之支鏈羥基或碳數為3至20之環狀羥基；且a代表0或1。The diamine component (b) of the present invention may comprise a diamine compound (b-2) represented by the following formula (IV).

In formula (IV), Z ₁ and Z ₅ independently represent a single bond, -CH ₂ - or -CH ₂ CH ₂ -; Z ₂ and Z ₄ independently represent -CH ₂ - or -CH ₂ CH ₂ -; Z ₃ represents an alkylene group or a cyclohexylene group with a carbon number of 1 to 6; Y ₁ and Y ₂ independently represent a single bond, -O-, -NH-, -N(CH ₃ )-, -C (=O)-, -C(=O)O-, -C(=O)NH-, -C(=O)N(CH ₃ )-, -OC(=O)-, -NHC(=O )- or N(CH ₃ )C(=O)-; Y ₃ represents a linear hydroxyl group with a carbon number of 1 to 20, a branched hydroxyl group with a carbon number of 3 to 20 or a cyclic hydroxyl group with a carbon number of 3 to 20 ; and a represents 0 or 1.

In formula (IV), Z ₁ and Z ₅ preferably represent a single bond or -CH ₂ -; Z ₂ and Z ₄ preferably represent -CH ₂ -. When Z ₁ and Z ₅ are the same, Z ₂ and Z ₄ are preferably different. When Z ₁ and Z ₅ are different, Z ₂ and Z ₄ are preferably the same.

In formula (IV), Y ₁ and Y ₂ preferably represent single bond, -O-, -C(=O)-, -C(=O)O-, -C(=O)NH-, -C (=O)N(CH ₃ )-, -OC(=O)-, -NHC(=O)- or N(CH ₃ )C(=O)-, more preferably, each independently represents a single bond or - O-, when Y ₁ and Y ₂ independently represent a single bond or -O-, the prepared liquid crystal alignment agent can further reduce the degree of flicker immediately after the formed liquid crystal display element is driven.

From the viewpoint of availability of raw materials, Y ₃ is preferably, for example, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, benzyl, n -hexadecyl or 9-fluorenylmethyl.

From the viewpoint of ease of synthesis, a is preferably 0.

(IV-1)

(IV-2)

(IV-3)

(IV-4)

(IV-5)

(IV-6)

(IV-7)

(IV-8)

(IV-9)

(IV-10)

(IV-11)

(IV-12)

(IV-13)

(IV-14)

(IV-15)

(IV-16)

(IV-17)

(IV-18)

(IV-19)

(IV-20)

(IV-21)

(IV-22)

(IV-23)

(IV-24)

(IV-25)

(IV-26)

(IV-27)

(IV-28)

(IV-29)

(IV-30)

(IV-31)

(IV-32)

(IV-33)

(IV-34)

(IV-35)

(IV-36)

(IV-37)

(IV-38)

(IV-39)

(IV-40)

(IV-41)

(IV-42)

(IV-43)

(IV-44)

(IV-45)

(IV-46) 於式(IV-1)至式(IV-46)中，Me代表甲基；Et代表乙基；i-Pr代表i-丙基；Bn代表芐基；且Boc代表tert-丁氧基羰基。Specific examples of the diamine compound (b-2) represented by the formula (IV) may include, but are not limited to, the diamine compounds represented by the following formulas (IV-1) to (IV-46).

(IV-1)

(IV-2)

(IV-3)

(IV-4)

(IV-5)

(IV-6)

(IV-7)

(IV-8)

(IV-9)

(IV-10)

(IV-11)

(IV-12)

(IV-13)

(IV-14)

(IV-15)

(IV-16)

(IV-17)

(IV-18)

(IV-19)

(IV-20)

(IV-21)

(IV-22)

(IV-23)

(IV-24)

(IV-25)

(IV-26)

(IV-27)

(IV-28)

(IV-29)

(IV-30)

(IV-31)

(IV-32)

(IV-33)

(IV-34)

(IV-35)

(IV-36)

(IV-37)

(IV-38)

(IV-39)

(IV-40)

(IV-41)

(IV-42)

(IV-43)

(IV-44)

(IV-45)

(IV-46) In formula (IV-1) to formula (IV-46), Me represents methyl; Et represents ethyl; i-Pr represents i-propyl; Bn represents benzyl; and Boc represents tert- Butoxycarbonyl.

The aforementioned diamine compound (b-2) may be used alone or in combination of two or more.

Based on the total usage amount of the diamine component (b) is 100 moles, the usage amount of the diamine compound (b-2) is 1 mole to 10 moles, preferably 1 mole to 8 moles, and more Preferably, it is 1 mole to 5 moles.

When the diamine component (b) contains the diamine compound (b-2), the prepared liquid crystal alignment agent can further reduce the degree of flicker immediately after the formed liquid crystal display element is driven.

Other diamine compounds (b-3)

The diamine component of the present invention may optionally contain other diamine compounds (b-3).

Other diamine compounds (b-3) may include but are not limited to 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminobutane Pentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diamino Decane, 4,4'-diaminoheptane, 1,3-diamino-2,2-dimethylpropane, 1,6-diamino-2,5-dimethylhexane, 1 ,7-diamino-2,5-dimethylheptane, 1,7-diamino-4,4-dimethylheptane, 1,7-diamino-3-methylheptane, 1,9-Diamino-5-methylnonane, 2,11-diaminododecane, 1,12-diaminooctadecane, 1,2-bis(3-aminopropoxy) ) ethane, 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylamine, 1,3-diaminocyclohexane, 1,4-Diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienediamine, tricyclo[6.2.1.0(2,7)]-undecenedimethyldiamine , 4,4'-methylenebis(cyclohexylamine), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diamine diphenyl ether, 4,4'-diaminobenzylaniline, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,5-diphenyl ether Aminonaphthalene, 5-amino-1-(4'-aminophenyl)-1,3,3-trimethylhydroindene, 6-amino-1-(4'-aminophenyl)- 1,3,3-Trimethylhydroindene, Hexahydro-4,7-methylhydroindenyl dimethylenediamine, 3,3'-diaminobenzophenone, 3,4'- Diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4 -(4-Aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenoxy)hexafluoropropane, 2,2-bis[4-(4-aminophenoxy) ) Phenyl] Di, 1,4-bis(4-aminophenoxy)cyclohexane, 1,5-bis(4-aminophenoxymethylene)adamantane, 1,4-bis(4-aminophenoxymethylene)adamantane 4-Aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 9,9-bis(4- Aminophenyl)-10-hydroanthracene, 9,10-bis(4-aminophenyl)anthracene [9,10-bis(4-aminophenyl) anthracene], 2,7-diaminophenyl, 9, 9-Bis(4-aminophenyl) benzene, 4,4'-methylene-bis(2-chloroaniline), 4,4'-(p-phenylene isopropylidene) bisaniline, 4 , 4'-(m-phenylene isopropylidene) bisaniline, 2,2'-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane, 4,4'-Bis[(4-amino-2-trifluoromethyl)phenoxy]-octafluorobiphenyl, 5-[4-(4-n-pentylcyclohexyl) ring Hexyl]phenylmethylene-1,3-diaminobenzene {5-[4-(4-n-pentylcyclohexyl) cyclohexyl] phenylmethylene-1,3-diaminobenzene}, 1,1-bis[4-(4 -Aminophenoxy)phenyl]-4-(4-ethylphenyl)cyclohexane{1,1-bis[4-(4-aminophenoxy)phenyl]-4-(4-ethylphenyl)cyclohexane} Or other diamine compounds represented by the following formula (VI-1) to formula (VI-29).

(VI-1) 於式(VI-1)中，F₁ 代表

、

、

、

、

或

，且F₂ 代表含甾基團、三氟甲基、氟基、碳數為2至30之烷基或衍生自吡啶、嘧啶、三嗪、哌啶及哌嗪等含氮原子環狀結構的一價基團。

(VI-1) In formula (VI-1), F ₁ represents

,

,

,

,

or

, and F ₂ represents a steroid group, a trifluoromethyl group, a fluoro group, an alkyl group with a carbon number of 2 to 30, or a nitrogen atom-containing cyclic structure derived from pyridine, pyrimidine, triazine, piperidine and piperazine. monovalent group.

(VI-1-1)

(VI-1-2)

(VI-1-3)

(VI-1-4)

(VI-1-5)

(VI-1-6)Other diamine compounds represented by the above formula (VI-1) are preferably 2,4-diaminophenyl ethyl formate, 3,5-diaminophenyl carboxylic acid Ethyl ester (3,5-diaminophenyl ethyl formate), 2,4-diaminophenyl propyl formate (2,4-diaminophenyl propyl formate), 3,5-diaminophenyl propyl formate (3,5-diaminophenyl propyl formate) -diaminophenyl propyl formate), 1-dodecoxy-2,4-diamino-benzene (1-dodecoxy-2,4-diamino-benzene), 1-hexadecoxy-2,4-diamine 1-hexadecoxy-2,4-diaminobenzene, 1-octadecoxy-2,4-diaminobenzene (1-octadecoxy-2,4-diaminobenzene) or the following formula (VI-1-1 ) to other diamine compounds represented by formula (VI-1-6).

(VI-1-1)

(VI-1-2)

(VI-1-3)

(VI-1-4)

(VI-1-5)

(VI-1-6)

(VI-2) 於式(VI-2)中，F₃ 代表

、

、

、

、

或

，F₄ 及F₅ 代表伸脂肪族環、伸芳香族環或伸雜環基團，且F₆ 代表碳數為3至18之烷基、碳數為3至18之烷氧基、碳數為1至5之氟烷基、碳數為1至5之氟烷氧基、氰基或鹵素原子。

(VI-2) In formula (VI-2), F ₃ represents

,

,

,

,

or

, F ₄ and F ₅ represent extended aliphatic ring, extended aromatic ring or extended heterocyclic group, and F ₆ represents an alkyl group with a carbon number of 3 to 18, an alkoxy group with a carbon number of 3 to 18, a carbon number is a fluoroalkyl group of 1 to 5, a fluoroalkoxy group having a carbon number of 1 to 5, a cyano group or a halogen atom.

(VI-2-1)

(VI-2-2)

(VI-2-3)

(VI-2-4)

(VI-2-5)

(VI-2-6)

(VI-2-7)

(VI-2-8)

(VI-2-9)

(VI-2-10)

(VI-2-11)

(VI-2-12)

(VI-2-13) 於式(VI-2-10)至式(VI-2-13)中，s可代表3至12的整數。The other diamine compounds represented by the above formula (VI-2) can preferably be the diamine compounds represented by the following formulas (VI-2-1) to (VI-2-13):

(VI-2-1)

(VI-2-2)

(VI-2-3)

(VI-2-4)

(VI-2-5)

(VI-2-6)

(VI-2-7)

(VI-2-8)

(VI-2-9)

(VI-2-10)

(VI-2-11)

(VI-2-12)

(VI-2-13) In formula (VI-2-10) to formula (VI-2-13), s may represent an integer of 3 to 12.

(VI-3) 於式(VI-3)中，F₇ 代表氫原子、碳數為1至5的醯基、碳數為1至5的烷基、碳數為1至5的烷氧基或鹵素。P1代表1至3的整數。當P1大於1時，複數個F₇ 可為相同或不同。

(VI-3) In formula (VI-3), F ₇ represents a hydrogen atom, an acyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or halogen. P1 represents an integer from 1 to 3. When P1 is greater than 1, the plurality of _F7 may be the same or different.

The diamine compound represented by the above formula (VI-3) is preferably selected from (1) P1 is 1: p-diamine benzene, m-diamine benzene, o-diamine benzene or 2,5-diamine Toluene, etc.; (2) P1 is 2:4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl- 4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 2,2'-dichloro-4,4'-diaminobiphenyl , 3,3'-dichloro-4,4'-diaminobiphenyl, 2,2',5,5'-tetrachloro-4,4'-diaminobiphenyl, 2,2'-diaminobiphenyl Chloro-4,4'-diamino-5,5'-dimethoxybiphenyl or 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, etc.; (3 ) P1 is 3:1,4-bis(4'-aminophenyl)benzene, etc., more preferably selected from p-diaminebenzene, 2,5-diaminetoluene, 4,4'-diamine Biphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl or 1,4-bis(4'-aminophenyl)benzene.

(VI-4) 於上式(VI-4)中，P2代表1至5的整數。式(VI-4)所示之結構較佳係選自於4,4'-二胺基二苯基硫醚。

(VI-4) In the above formula (VI-4), P2 represents an integer of 1 to 5. The structure represented by formula (VI-4) is preferably selected from 4,4'-diaminodiphenyl sulfide.

(VI-5) 於式(VI-5)中，F₈ 及F₁₀ 可為相同或不同，且分別代表二價有機基團，F₉ 代表衍生自吡啶、嘧啶、三嗪、哌啶及哌嗪等含氮原子環狀結構的二價基團。

(VI-5) In formula (VI-5), F ₈ and F ₁₀ may be the same or different, and represent a divalent organic group, respectively, and F ₉ represents derived from pyridine, pyrimidine, triazine, piperidine and piperidine A divalent group with a nitrogen atom-containing cyclic structure such as oxazine.

(VI-6) 於式(VI-6)中，F₁₁ 、F₁₂ 、F₁₃ 及F₁₄ 分別可為相同或不同，且可代表碳數為1至12的烴基。P3代表1至3的整數，且P4代表1至20的整數。

(VI-6) In formula (VI-6), F ₁₁ , F ₁₂ , F ₁₃ and F ₁₄ may be the same or different, respectively, and may represent a hydrocarbon group having 1 to 12 carbons. P3 represents an integer of 1 to 3, and P4 represents an integer of 1 to 20.

(VI-7) 於式(VI-7)中，F₁₅ 代表

或伸環己烷基，F₁₆ 代表

，F₁₇ 代表伸苯基或伸環己烷基，且F₁₈ 代表氫原子或碳數1至8的烷基。

(VI-7) In formula (VI-7), F ₁₅ represents

or cyclohexylene, F ₁₆ stands for

, F ₁₇ represents a phenylene group or a cyclohexylene group, and F ₁₈ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.

(VI-7-1)

(VI-7-2)The diamine compound represented by the above formula (VI-7) is preferably selected from the diamine compounds represented by the following formula (VI-7-1) and formula (VI-7-2).

(VI-7-1)

(VI-7-2)

(VI-8)

(VI-9)

(VI-10)

(VI-11)

(VI-12)

(VI-13)

(VI-14)

(VI-15)

(VI-16)

(VI-17)

(VI-18)

(VI-19)

(VI-20)

(VI-21)

(VI-22)

(VI-23)

(VI-24)

(VI-25)

(VI-26)

(VI-27)

(VI-28)

(VI-29) 於式(VI-16)至式(VI-19)中，F₁₉ 較佳係碳數為1至10之烷基或碳數為1至10之烷氧基。於式(VI-20)至式(VI-24)中，F₂₀ 較佳為氫原子、碳數為1至10之烷基或碳數為1至10之烷氧基。Other diamine compounds represented by formula (VI-8) to formula (VI-29) are shown below:

(VI-8)

(VI-9)

(VI-10)

(VI-11)

(VI-12)

(VI-13)

(VI-14)

(VI-15)

(VI-16)

(VI-17)

(VI-18)

(VI-19)

(VI-20)

(VI-21)

(VI-22)

(VI-23)

(VI-24)

(VI-25)

(VI-26)

(VI-27)

(VI-28)

(VI-29) In formula (VI-16) to formula (VI-19), F ₁₉ is preferably an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms. In formula (VI-20) to formula (VI-24), F ₂₀ is preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.

Other diamine compounds (b-3) may preferably include but are not limited to 1,2-diaminoethane, 4,4'-diaminodicyclohexylmethane, 4,4'-diaminodiphenyl Methane, 4,4'-diaminodiphenyl ether, 5-[4-(4-n-pentylcyclohexyl)cyclohexyl]phenylmethylene-1,3-diaminobenzene, 1, 3-bis(3-aminophenoxy)benzene, 1,1-bis[4-(4-aminophenoxy)phenyl]-4-(4-ethylphenyl)cyclohexane, 2 ,4-Diaminophenylcarboxylate, p-diamine benzene, m-diamine benzene, o-diamine benzene, formula (VI-1-1), formula (VI-1-2), formula ( VI-1-5), formula (VI-2-1), formula (VI-2-11), formula (VI-7-1), formula (VI-25) or formula (VI-28) compound.

The aforementioned other diamine compounds (b-3) may be used alone or in combination of two or more.

Based on the total usage amount of the diamine component (b) is 100 moles, the usage amount of the other diamine compounds (b-3) is 40 moles to 94 moles, preferably 52 moles to 94 moles, and More preferably, it is 65 moles to 94 moles.

Preparation method of polymer (A)

The preparation of the polyamic acid polymer of the present invention can be carried out by a general method. Preferably, the preparation method of the polyamic acid polymer described above comprises the following steps: comprising the tetracarboxylic dianhydride component (a) and diamine The mixture of component (b) is dissolved in a solvent, and the polycondensation reaction is carried out at a temperature of 0°C to 100°C for 1 hour to 24 hours, and then the above-mentioned reaction solution is subjected to a vacuum distillation method with an evaporator, A polyamide acid polymer can be obtained, or the above-mentioned reaction solution is poured into a large amount of poor solvent to obtain a precipitate, and then the aforesaid precipitate is dried by drying under reduced pressure to obtain a polyamide acid. polymer.

The solvent used in the polycondensation reaction can be the same as or different from the solvent (B) in the following liquid crystal alignment agent, and the solvent used in the polycondensation reaction is not particularly limited, as long as it can dissolve the reactant and the product. Can. Preferably, the solvent includes but is not limited to (1) aprotic polar solvents, such as: N-methyl-2-pyrrolidinone (N-methyl-2-pyrrolidinone; NMP), N,N-dimethylacetamide , aprotic polar solvents such as N,N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethyl urea or hexamethylphosphoric triamine; (2) phenolic solvents, For example: phenolic solvents such as m-cresol, xylenol, phenol or halogenated phenols. The amount of the solvent used in the polycondensation reaction is preferably 200 to 2000 parts by weight, more preferably 300 to 1800 parts by weight, based on 100 parts by weight of the mixture.

In particular, in the polycondensation reaction, an appropriate amount of poor solvent can be used in combination with the solvent, wherein the poor solvent will not cause the precipitation of the polyamic acid polymer. The poor solvent can be used alone or in combination, and it includes but is not limited to (1) alcohols, such as methanol, ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol Alcohols such as alcohol or triethylene glycol; (2) ketones, such as ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; (3) esters, such as: Esters of methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, diethyl malonate or ethylene glycol ethyl ether acetate; (4) ethers, such as diethyl ether, Ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether or diethylene glycol dimethyl ether ethers such as base ethers; (5) halogenated hydrocarbons, such as dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene or o-dichloromethane Halogenated hydrocarbons such as benzene; (6) Hydrocarbons, such as: tetrahydrofuran, hexane, heptane, octane, benzene, toluene or xylene and other hydrocarbons or any combination of the above solvents. The use amount of the lean solvent is preferably 0 to 60 parts by weight, more preferably 0 to 50 parts by weight, based on 100 parts by weight of the diamine component (b).

The preparation of the polyimide polymer of the present invention can be carried out by a general method. Preferably, the preparation method of the polyimide polymer first dissolves the mixture in a solution, wherein the mixture comprises the tetracarboxylic dianhydride component (a ) and the diamine component (b), and carry out a polymerization reaction to form a polyamic acid polymer. Next, in the presence of a dehydrating agent and a catalyst, further heating is performed, and a dehydration ring-closure reaction is carried out, so that the aramidic acid functional group in the polyamic acid polymer is converted into an amide-imide functional group (that is, an amide-imide functional group) through the dehydration ring-closure reaction. amination) to obtain a polyimide polymer.

The solvent used in the dehydration ring-closure reaction can be the same as the solvent in the liquid crystal alignment agent described below, so it will not be repeated. The amount of the solvent used in the dehydration ring-closure reaction is preferably 200 to 2000 parts by weight, more preferably 300 to 1800 parts by weight, based on 100 parts by weight of the polyamide polymer.

In order to obtain a better degree of imidization of the polyamic acid polymer, the operating temperature of the dehydration ring-closure reaction is preferably 40°C to 200°C, more preferably 40°C to 150°C. If the operating temperature of the dehydration ring-closure reaction is lower than 40°C, the imidization reaction is incomplete, and the degree of imidization of the polyamic acid polymer is reduced. However, if the operating temperature of the dehydration ring-closure reaction is higher than 200°C, the weight-average molecular weight of the obtained polyimide polymer is relatively low.

The dehydrating agent used in the dehydration ring-closure reaction can be selected from acid anhydride compounds, such as acid anhydride compounds such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride. The dehydrating agent is used in an amount of 0.01 mol to 20 mol based on 1 mol of the polyamide polymer. The catalyst used in the dehydration ring-closure reaction can be selected from (1) pyridine compounds, such as: pyridine compounds such as pyridine, collidine or lutidine; (2) tertiary amine compounds, such as: Tertiary amine compounds such as triethylamine. The used amount of the dehydrating agent is 1 mol, and the used amount of the catalyst is 0.5 mol to 10 mol.

Preferred specific examples of the polyimide-based block copolymer of the present invention are polyimide block copolymer, polyimide block copolymer, polyimide-polyimide block Copolymers, or any combination thereof.

The polyimide-based block copolymer of the present invention can be prepared by a general method. Preferably, in the preparation method of the polyimide-based block copolymer, the starting material is first dissolved in a solvent, and the Polycondensation reaction, wherein the starting material comprises the above-mentioned at least one polyimide polymer and/or the above-mentioned at least one polyimide polymer, and may further comprise a tetracarboxylic dianhydride component (a) and the diamine component (b).

The tetracarboxylic dianhydride component (a) and the diamine component (b) in the aforementioned starting material are the same as the tetracarboxylic dianhydride component (a) and the diamine component (a) and the The amine component (b) is the same, and the solvent used in the polycondensation reaction can be the same as the solvent in the liquid crystal aligning agent described below, which will not be repeated here.

The amount of the solvent used in the polycondensation reaction is preferably 200 to 2000 parts by weight, more preferably 300 to 1800 parts by weight, based on 100 parts by weight of the aforementioned starting materials. The operating temperature of the polycondensation reaction is preferably 0°C to 200°C, and more preferably 0°C to 100°C.

Preferably, the starting materials include but are not limited to (1) two kinds of polyamide polymers with different end groups and different structures; (2) two kinds of polyimides with different end groups and different structures polymers; (3) polyamide polymers and polyimide polymers with different terminal groups and structures; (4) polyamide polymers, tetracarboxylic dianhydride compounds and diamine compounds, Wherein, at least one of the tetracarboxylic dianhydride compound and the diamine compound has a different structure from the tetracarboxylic dianhydride component (a) and the diamine component (b) used to form the polyamic acid polymer ; (5) Polyimide polymer, tetracarboxylic dianhydride compound and diamine compound, wherein at least one of the tetracarboxylic dianhydride compound and diamine compound is used for forming the polyimide polymer The structures of the tetracarboxylic dianhydride component (a) and the diamine component (b) are different; (6) polyamide acid polymer, polyimide polymer, tetracarboxylic dianhydride compound and diamine A compound, wherein at least one of a tetracarboxylic dianhydride compound and a diamine and the tetracarboxylic dianhydride component (a) and the diamine component used to form a polyamic acid polymer or a polyimide polymer (b) The structures are different; (7) Two kinds of polyamide polymers, tetracarboxylic dianhydride compounds and diamine compounds with different structures; (8) Two kinds of polyimide polymers with different structures , tetracarboxylic dianhydride compounds and diamine compounds; (9) two kinds of end groups are acid anhydride groups and have different structures of polyamide polymers and diamine compounds; (10) two kinds of end groups are amine groups and have different structures Dissimilar polyimide polymers and tetracarboxylic dianhydride compounds; (11) Two kinds of end groups are acid anhydride groups and structurally different polyimide polymers and diamine compounds; (12) Two kinds of end groups Polyimide polymers and tetracarboxylic dianhydride compounds with amine groups and different structures.

Within the scope of not affecting the efficacy of the present invention, preferably, the aforementioned polyimide polymer, the aforementioned polyimide polymer, and the aforementioned polyimide-based block copolymer may be the end of which the molecular weight is adjusted first. Modified polymers. By using the terminal-modified polymer, the coating performance of the liquid crystal alignment agent can be improved. The method for preparing the aforementioned terminal-modified polymer can be prepared by adding a monofunctional compound while the polyamide acid polymer undergoes a polycondensation reaction, and the monofunctional compound includes but is not limited to (1) a monobasic acid anhydride, such as : Monobasic acid anhydride such as maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride or n-hexadecyl succinic anhydride; ( 2) Monoamine compounds, such as: aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine Monoamine compounds such as alkylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine or n-eicosylamine; (3) Monoisocyanate compounds, such as monoisocyanate compounds such as phenyl isocyanate or naphthyl isocyanate.

The polymer (A) of the present invention has a weight average molecular weight of 10,000 to 90,000 in terms of polystyrene as measured by gel permeation chromatography, preferably 12,000 to 75,000, and more preferably 15,000 to 60,000.

Solvent (B)

The solvent used in the liquid crystal aligning agent of the present invention is not particularly limited, as long as it can dissolve the polymer (A) and other optional components, and does not react with them, preferably the same as the aforementioned synthetic polyamide acid. As for the solvent to be used, the poor solvent used in the synthesis of the aforementioned polyamic acid may also be used in combination.

Specific examples of the solvent (B) include, but are not limited to, N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, Ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl Ethyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether base ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether Acetate or N,N-dimethylformamide or N,N-dimethylacetamide (N,N-dimethylacetamide) and the like.

The aforementioned solvent (B) may be used alone or in combination of two or more.

Based on 100 parts by weight of the polymer (A), the amount of the solvent (B) used is 800 to 4000 parts by weight, preferably 900 to 3500 parts by weight, and more preferably 1000 to 3000 parts by weight .

Additives (C)

The liquid crystal alignment agent of the present invention may optionally contain an additive (C) within the scope of not affecting the efficacy of the present invention, and the additive (C) may be an epoxy compound or a silane compound having a functional group. The function of the additive (C) is to improve the adhesion of the liquid crystal alignment film to the surface of the substrate. The additives (C) may be used alone or in combination of two or more.

The aforementioned epoxy compounds may include but are not limited to ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol Diglycidyl Ether, Neopentyl Glycol Diglycidyl Ether, 1,6-Hexanediol Diglycidyl Ether, Glycerol Diglycidyl Ether, 2,2-Dibromoneopentyl Diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N',N'-tetraglycidyl-m-di Toluenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-di Aminodiphenylmethane, N,N-glycidyl-p-glycidoxyaniline, 3-(N-allyl-N-glycidyl)aminopropyltrimethoxysilane, 3-(N,N-diepoxypropyl)aminopropyltrimethoxysilane, etc.

The epoxy compound is generally used in an amount of 40 parts by weight or less, and preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the polymer (A).

The above-mentioned silane compounds with functional groups may include, but are not limited to, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltrimethoxysilane, Aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyl 3-ureidopropyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane Silane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine Triamine, 10-trimethoxysilyl-1,4,7-triazdecane, 10-triethoxysilyl-1,4,7-triazdecane, 9-trimethoxysilyl- 3,6-Diaznonyl acetate, 9-triethoxysilyl-3,6-diaznonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N- Benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N -Bis(ethylene oxide)-3-aminopropyltrimethoxysilane, N-bis(ethylene oxide)-3-aminopropyltriethoxysilane, etc.

Based on 100 parts by weight of the polymer (A), the amount of the silane compound used is generally 10 parts by weight or less, and preferably 0.5 parts by weight to 10 parts by weight.

The additive (C) may be used in an amount of 0.5 to 50 parts by weight, and preferably 1 to 45 parts by weight, based on 100 parts by weight of the polymer (A).

Preparation method of liquid crystal alignment agent

The preparation method of the liquid crystal alignment agent of the present invention is not particularly limited, and a general mixing method can be used, such as first mixing the tetracarboxylic dianhydride component (a) and the diamine component (b) uniformly, and then react to form a polymerization Object (A). Next, add the solvent (B) and the additive (C) to the polymer (A) at a temperature of 0° C. to 200° C., and continue stirring with a stirring device until dissolved. Preferably, the polymer (A) and the additive (C) are added to the solvent (B) at a temperature of 20°C to 60°C.

Method for forming liquid crystal alignment film

The liquid crystal alignment film of the present invention is a film prepared by coating the liquid crystal alignment agent formed above on a substrate, drying and baking.

The substrate coated by the liquid crystal alignment agent of the present invention is selected from transparent materials, wherein the transparent materials include but are not limited to alkali-free glass, soda lime glass, hard glass (Pyles glass), quartz glass for liquid crystal display devices , polyethylene terephthalate, polybutylene terephthalate, polyether terephthalate, polycarbonate, etc., preferably using ITO electrodes for liquid crystal driving that have been formed on the substrate to simplify the process. Furthermore, for a reflective liquid crystal display having only a single-sided substrate, the substrate may be made of an opaque material such as silicon wafer, and the electrodes in this case may be formed of a material that reflects light such as aluminum. The coating method of the liquid crystal aligning agent of the present invention can be, for example, a spin coating method, a printing method, an inkjet method, or the like.

The liquid crystal aligning agent of the present invention can choose any temperature and time to carry out the drying and baking processes after coating. In general, in order to sufficiently remove the contained organic solvent, drying at 50°C to 120°C for 1 minute to 10 minutes is required. After that, bake at 150°C to 300°C for 5 minutes to 120 minutes. The thickness of the coating film after baking is not particularly limited, but an excessively thin coating film will cause the deterioration of the reliability of the liquid crystal display, so the above coating film thickness is preferably 5 nm to 300 nm, and 10 nm to 200 nm. is better.

Although the liquid crystal alignment agent of the present invention can be subjected to the conventional rubbing alignment treatment, the effect is better when the photo alignment treatment method is used.

A specific example of the photo-alignment treatment method can be, for example, irradiating the surface of the above-mentioned coating film with radiation polarized in a specific direction, and then performing heat treatment at a temperature of 150° C. to 250° C. as the case may be, so as to impart the above-mentioned coating film with liquid crystal alignment energy. . Among them, ultraviolet rays or visible light with wavelengths of 100 nm to 800 nm can be used as the above-mentioned radiation, and ultraviolet rays with wavelengths of 100 nm to 400 nm are preferable, and those with wavelengths of 200 nm to 400 nm are more preferable. Furthermore, in order to improve the liquid crystal alignment, the coated substrate may be irradiated with radiation while the coated substrate is heated at 50°C to 250°C. The irradiation dose of the aforementioned radiation is preferably 1 mJ/cm ² to 10,000 mJ/cm ² , and more preferably 100 mJ/cm ² to 5,000 mJ/cm ² . The liquid crystal alignment film prepared in the above manner can stably align the liquid crystal molecules in a certain direction.

The liquid crystal alignment agent of the present invention is subjected to pre-baking treatment, post-baking treatment and photo-alignment treatment to form a liquid crystal alignment film, and the pretilt angle of the liquid crystal alignment film is 0° to 3°.

Manufacturing method of liquid crystal display element

The present invention further provides a liquid crystal display element comprising the aforementioned liquid crystal alignment film.

The manufacturing method of the liquid crystal display element is well known to those skilled in the art, therefore, the following description is only briefly made.

Referring to FIG. 1, a preferred embodiment of the liquid crystal display element 100 of the present invention includes a first unit 110, a second unit 120 and a liquid crystal unit 130, wherein the second unit 120 and the first unit 110 are spaced opposite to each other, and the liquid crystal unit 130 is disposed in the first unit 130. between the first unit 110 and the second unit 120 .

The first unit 110 includes a first substrate 112, an electrode 114 and a first liquid crystal alignment film 116, wherein the electrode 114 is formed on the surface of the first substrate 112 in a patterned manner, and the first liquid crystal alignment film 116 is formed on the electrode 114's surface.

The second unit 120 includes a second substrate 122 and a second liquid crystal alignment film 126 , wherein the second liquid crystal alignment film 126 is formed on the surface of the second substrate 122 .

The first substrate 112 and the second substrate 122 are selected from transparent materials, etc., wherein the transparent materials include but are not limited to alkali-free glass, soda lime glass, hard glass (Pyles glass), and quartz glass for liquid crystal display devices , polyethylene terephthalate, polybutylene terephthalate, polyether terephthalate, polycarbonate, etc. The material of the electrode 114 is a transparent electrode selected from tin oxide (SnO ₂ ), indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ), etc.; or a metal electrode such as chromium.

The first liquid crystal alignment film 116 and the second liquid crystal alignment film 126 are respectively the above-mentioned liquid crystal alignment films, and their functions are to make the liquid crystal cell 130 form a pretilt angle, and the liquid crystal cell 130 can be driven by the parallel electric field generated by the electrode 114 .

The liquid crystals used in the liquid crystal unit 130 can be used alone or in combination, and the liquid crystals include, but are not limited to, diaminobenzene liquid crystals, pyridazine liquid crystals, Schiff base liquid crystals, and azo-based liquid crystals. (azoxy) liquid crystal, biphenyl liquid crystal, phenylcyclohexane liquid crystal, biphenyl liquid crystal, phenylcyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal , biphenylcyclohexane (biphenylcyclohexane) liquid crystal, pyrimidine (pyrimidine) liquid crystal, dioxane (dioxane) liquid crystal, bicyclooctane (bicyclooctane) liquid crystal, cubane (cubane) liquid crystal, etc. Add cholesteryl liquid crystals such as cholesteryl chloride, cholesteryl nonanoate, cholesteryl carbonate, etc., or use the trade names "C-15" and "CB-15" A chiral agent (manufactured by Merck & Co., Ltd.) or the like, or a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate.

The liquid crystal display element produced by the liquid crystal alignment agent of the present invention is suitable for various types of nematic liquid crystals, such as liquid crystal display elements of TN, STN, TFT, VA, IPS and the like. In addition, depending on the selected liquid crystal, it can also be used for liquid crystal display elements with different inductive properties or anti-inductive properties. Among the above-mentioned liquid crystal display elements, it is particularly suitable for an IPS type liquid crystal display element.

The following examples are used to illustrate the application of the present invention, but it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention.

Preparation of polymer (A-1)

Synthesis Example A-1-1

A nitrogen inlet, a stirrer, a condenser and a thermometer are set on a four-necked conical flask with a volume of 500 ml, and nitrogen is introduced. Then, 0.87 g (0.0025 mol) of the diamine compound (b-1-4) represented by the formula (II-2-12), 0.235 g (0.0005 mol) of the diamine compound (b-1-4) represented by the formula (IV-3) were added Shown the diamine compound (b-2-1) and 5.076 g (0.047 mol) of p-diamine benzene (b-3-1) and 80 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) , and stirred at room temperature until dissolved. Next, 11.2 g (0.05 mol) of the compound (a-1-1) represented by the formula (I-1) and 20 g of NMP were added and reacted at room temperature for 2 hours. After the reaction, the reaction solution was poured into 1500 ml of water to precipitate the polymer, the obtained polymer was filtered, and the steps of washing and filtering with methanol were repeated three times. Afterwards, the product was placed in a vacuum oven and dried at a temperature of 60° C. to obtain the polymer (A-1-1) of Synthesis Example A-1-1, the formula of which is shown in Table 1.

Synthesis Example A-1-2 to Synthesis Example A-1-15 and Comparative Synthesis Example A'-1-1 to Comparative Synthesis Example A'-1-4

Synthesis Example A-1-2 to Synthesis Example A-1-15 and Comparative Synthesis Example A'-1-1 to Comparative Synthesis Example A'-1-4 use the polymer (A- 1-1) The preparation method is the same as the preparation method, the difference is that the synthesis example A-1-2 to the synthesis example A-1-15 and the comparative synthesis example A'-1-1 to the comparative synthesis example A'-1- 4. Change the type and usage amount of the raw materials in the polymer, and its formula is shown in Table 1, and will not be repeated here.

Preparation of polymer (A-2)

Synthesis Example A-2-1

A nitrogen inlet, a stirrer, a condenser and a thermometer are set on a four-necked conical flask with a volume of 500 ml, and nitrogen is introduced. Then, 0.87 g (0.0025 mol) of the diamine compound (b-1-4) represented by the formula (II-2-12), 0.235 g (0.0005 mol) of the diamine compound (b-1-4) represented by the formula (IV-3) were added Shown the diamine compound (b-2-1) and 5.076 g (0.047 mol) of p-diamine benzene (b-3-1) and 80 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) , and stirred at room temperature until dissolved. Next, 11.2 g (0.05 mol) of compound (a-1-1) represented by formula (I-1) and 20 g of NMP were added. After reacting at room temperature for 6 hours, 97 g of NMP, 2.55 g of acetic anhydride and 19.75 g of pyridine were added, the temperature was raised to 60° C., and stirring was continued for 2 hours to carry out imidization reaction. After the reaction was completed, the reaction solution was poured into 1500 ml of water to precipitate the polymer. Then, filter the obtained polymer, repeat washing and filtration with methanol three times, put it in a vacuum oven, and dry it at a temperature of 60° C. to obtain polymer (A-2-1), the formula of which is shown in Table 1. shown.

Synthesis Example A-2-2 to Synthesis Example A-2-5 and Comparative Synthesis Example A'-2-1 to Comparative Synthesis Example A'-2-3

Synthesis Example A-2-2 to Synthesis Example A-2-5 and Comparative Synthesis Example A'-2-1 to Comparative Synthesis Example A'-2-3 use the polymer (A- 2-1) The preparation method of the same preparation method, the difference is that A-2-2 changes to Synthesis Example A-2-5 and Comparative Synthesis Example A'-2-1 to Comparative Synthesis Example A'-2-3 The type and usage amount of the raw materials in the polymer, the formula is shown in Table 1, and will not be repeated here.

Preparation of liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element

Example 1

Weigh 100 parts by weight of the polymer (A-1-1) prepared in Synthesis Example A-1-1 and 800 parts by weight of NMP (B-1), and stir and mix at room temperature to obtain The liquid crystal alignment agent of Example 1.

The liquid crystal aligning agent prepared in Example 1 was spin-coated on a glass substrate, and the glass substrate had pixel electrodes, wherein the pixel electrodes had a pair of ITO electrodes (electrode width: 10 μm, electrode spacing: 10 μm, electrode height: 50 nm) IPS driving electrodes, the pair of ITO electrodes have a comb-like shape respectively, and the comb-like parts of each other are arranged in a manner of being separated and engaged. Then, the glass substrate coated with the liquid crystal alignment agent was dried on a hot plate at 80°C, and after 5 minutes, it was baked in a hot air circulating oven at 250°C for 60 minutes to form a coating film with a thickness of 100 nm. .

Through a polarizing plate, ultraviolet rays with a wavelength of 254 nm are irradiated on the surface of the coating film, so as to obtain a substrate with a liquid crystal alignment film. Next, similarly, a coating film was formed on an opposing substrate, which was a glass substrate having no electrodes but having columnar spacers having a height of 4 μm, and an alignment treatment was applied.

The above-mentioned two substrates are a set, and one of them is printed with a sealant, and the other is faced with the liquid crystal alignment film and the alignment direction is 0∘ to bond the two. Then, the encapsulant is hardened to produce an empty unit cell. After that, liquid crystal MLC-2041 (manufactured by Merck) was injected into the empty cell by the reduced pressure injection method, and the injection port was sealed to obtain the liquid crystal display element of Example 1.

The obtained liquid crystal display element was evaluated by the following evaluation methods, and the results are shown in Table 2. The method for detecting the degree of flicker immediately after driving will be described later.

Example 2 to Example 20 and Comparative Example 1 to Comparative Example 7

Examples 2 to 20 and Comparative Examples 1 to 7 use the same preparation methods as the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element of Example 1, except that Examples 2 to 20 are different from In Comparative Examples 1 to 7, the types and amounts of raw materials in the liquid crystal alignment agent were changed. The formulations and evaluation results are shown in Tables 2 and 3, respectively, and will not be repeated here.

於第3表中，B-1、B-2、B-3、C-1與C-2之種類如第2表所述，在此不另贅述。

In Table 3, the types of B-1, B-2, B-3, C-1 and C-2 are as described in Table 2, and will not be repeated here.

Evaluation method

Immediate flicker after driving

The obtained liquid crystal display element is placed between two polarizers whose polarizing axes are arranged in a vertically crossed manner, the LED backlight is lit in the state of no applied voltage, and the arrangement angle of the liquid crystal display element is adjusted to make the transmitted light brightness. to the minimum state. Next, an AC voltage with a frequency of 30 Hz was applied to the liquid crystal display element, and a V-T curve (voltage-transmittance curve) was measured at the same time, and an AC voltage with a relative transmittance of 23% was calculated as a driving voltage.

(VII) 於式(VII)中，z為使用上述裝置34970A，以相對透過率為23%之頻率30 Hz的交流電壓驅動時所讀取之亮度值。 ※：FL＜2%。 ◎：3%＞FL≧2%。 ○：4%＞FL≧3%。 △：5%＞FL≧4%。 ╳：FL≧5%。The method for measuring the flicker after driving is to turn off the lit LED backlight under the temperature condition that the temperature of the liquid crystal display element is 23°C, and after shading for 72 hours, turn it on again, and turn on the backlight. At the beginning, an AC voltage with a frequency of 30 Hz with a relative transmittance of 23% was applied, and the liquid crystal display element was driven for 60 minutes, and the amplitude of the flicker was tracked. The amplitude of the flicker is to use the data acquisition/data recording switching device 34970A (manufactured by Agilent Technologies) connected with the photodiode and the IV conversion amplifier to read the luminance value passing through the two polarizers and the liquid crystal display element in between them. . The degree of flicker (FL) is calculated according to the following formula (VII), and the lower the degree of flicker, the better the quality of the liquid crystal display element prepared with the liquid crystal alignment agent.

(VII) In formula (VII), z is the luminance value read when the above-mentioned device 34970A is used to drive with an AC voltage with a frequency of 30 Hz with a relative transmittance of 23%. ※: FL＜2%. ◎: 3%>FL≧2%. ○: 4%>FL≧3%. △: 5%>FL≧4%. ╳: FL≧5%.

As can be seen from the results in Tables 2 and 3, if the tetracarboxylic dianhydride component (a) of the liquid crystal alignment agent of the present invention does not contain the tetracarboxylic dianhydride compound (a-1) represented by formula (I), The resulting liquid crystal display element has a poor degree of flicker immediately after driving. Secondly, if the diamine component (b) of the liquid crystal aligning agent of the present invention does not contain the diamine compound (b-1) represented by the formula (II), the degree of flicker immediately after the driving of the formed liquid crystal display element is not high. good.

If the diamine compound (b-1) represented by the formula (II) has the diamine compound represented by the aforementioned formulas (II-1-1) to (II-1-3), the formed liquid crystal display The degree of flicker immediately after the driving of the device can be further reduced.

In addition, when the diamine component (b) of the liquid crystal alignment agent of the present invention contains the diamine compound (b-2) represented by the formula (IV), the degree of flicker immediately after the driving of the formed liquid crystal display element can be improved. further reduced.

It should be added that although the present invention uses specific compounds, compositions, reaction conditions, manufacturing processes, analytical methods or specific instruments as examples to describe the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element of the present invention, the present invention belongs to the technical field Anyone with ordinary knowledge in the present invention will know that the present invention is not limited to this, and other compounds, compositions, reactions can also be used in the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element of the present invention without departing from the spirit and scope of the present invention. conditions, processes, analytical methods or instruments.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the appended patent application.

100: Liquid crystal display element 110: Unit 1 112: The first substrate 114: The first conductive film 116: the first liquid crystal alignment film 120: Unit Two 122: Second substrate 126: The second liquid crystal alignment film 130: Liquid crystal unit

In order to have a more complete understanding of the embodiments of the present invention and their advantages, please refer to the following description together with the corresponding drawings. It must be emphasized that the various features are not drawn to scale and are for illustrative purposes only. The relevant diagrams are described as follows: FIG. 1 is a schematic diagram illustrating a structure of a liquid crystal display device according to an embodiment of the present invention.

Domestic storage information (please note in the order of storage institution, date and number) without Foreign deposit information (please note in the order of deposit country, institution, date and number) without

100: Liquid crystal display element

110: Unit 1

112: The first substrate

114: The first conductive film

116: the first liquid crystal alignment film

120: Unit Two

122: Second substrate

126: The second liquid crystal alignment film

130: Liquid crystal unit

Claims (10)

A liquid crystal alignment agent, comprising: a polymer (A), prepared by a polymerization reaction of a tetracarboxylic dianhydride component (a) and a diamine component (b), wherein the tetracarboxylic dianhydride component (a) contains at least one tetracarboxylic dianhydride compound (a-1) represented by the following formula (I), and the diamine component (b) contains a diamine compound (b-) represented by the following formula (II) 1):

In the formula (I), R ₁ to R ₄ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a group having 2 to 6 carbon atoms. Alkynyl group, monovalent organic group containing fluorine atom and carbon number of 1 to 6 or phenyl group, R ₁ to R ₄ are the same or different, and at least one of R ₁ , R ₂ , R ₃ and R ₄ not a hydrogen atom;

In the formula (II), M ₁ and M ₂ independently represent single bond, -O-, -S-, -NM ₃ -, ester group, amido group, thioester group, urea group, carbonate group or a urethane group, wherein M ₃ represents a hydrogen atom or a methyl group, and M ₁ and M ₂ may be the same or different; A represents an alkylene group with a carbon number of 2 to 20; X ₁ and X ₂ are independently Represents a divalent organic group represented by the following formulas (III-1) to (III-19), and X ₁ and X ₂ are selected from different ones in the formulas (III-1) to (III-19) Two structures, wherein at least one of X ₁ and X ₂ represents the structure shown in formula (III-17), formula (III-18) or formula (III-19):

In the formula (III-2), X ₃ represents an alkylene group having 1 to 5 carbon atoms; in the formula (III-14), X ₄ represents a hydrogen atom, a halogen atom, a methyl group, a hydroxyl group or a methoxy group In the formula (III-17), X ₅ and X ₆ independently represent a halogen atom, a methyl group, a hydroxyl group or a methoxy group; in the formula (III-18), X ₇ and X ₈ are each independently Ground represents a hydrogen atom, a halogen atom, a methyl group, a hydroxyl group or a methoxy group, and at least one of X ₇ and X ₈ is not a hydrogen atom; and a solvent (B). The liquid crystal alignment agent according to claim 1, wherein the diamine compound (b-1) is selected from the following diamine compounds represented by formula (II-1-1) to formula (II-1-3):

In the formula (II-1-1) to the formula (II-1-3), the definitions of A, M ₁ , M ₂ , X ₅ , X ₆ , X ₇ and X ₈ are as described above. The liquid crystal alignment agent according to claim 1, wherein the diamine component (b) comprises a diamine compound (b-2) represented by the following formula (IV):

In the formula (IV), Z ₁ and Z ₅ independently represent a single bond, -CH ₂ - or -CH ₂ CH ₂ -; Z ₂ and Z ₄ independently represent -CH ₂ - or -CH ₂ CH ₂ -; Z ₃ represents an alkylene group or a cyclohexylene group with a carbon number of 1 to 6; Y ₁ and Y ₂ independently represent a single bond, -O-, -NH-, -N(CH ₃ )-, - C(=O)-, -C(=O)O-, -C(=O)NH-, -C(=O)N(CH ₃ )-, -OC(=O)-, -NHC(= O)- or N(CH ₃ )C(=O)-; Y ₃ represents a straight-chain hydroxyl group with a carbon number of 1 to 20, a branched hydroxyl group with a carbon number of 3 to 20 or a cyclic hydroxyl group with a carbon number of 3 to 20 and a represents 0 or 1. The liquid crystal aligning agent according to claim 3, wherein Y ₁ and Y ₂ independently represent a single bond or -O-. The liquid crystal alignment agent according to claim 3, wherein a represents 0. The liquid crystal alignment agent according to claim 1, wherein based on the total usage of the tetracarboxylic dianhydride component (a) is 100 moles, the usage of the tetracarboxylic dianhydride compound (a-1) is 10 moles mol to 100 mol, and based on the total usage amount of the diamine component (b) is 100 mol, the usage amount of the diamine compound (b-1) is 5 mol to 50 mol. The liquid crystal aligning agent according to claim 3, wherein based on the total usage amount of the diamine component (b) is 100 moles, the usage amount of the diamine compound (b-2) is 1 mole to 10 moles . The liquid crystal alignment agent according to claim 1, wherein based on the total usage of the polymer (A) is 100 parts by weight, the usage of the solvent (B) is 800 to 4000 parts by weight. A liquid crystal alignment film formed by using the liquid crystal alignment agent according to any one of claims 1 to 8. A liquid crystal display element, comprising the liquid crystal alignment film according to claim 9.

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