TWI858879B - Liquid crystal alignment agent for photo-alignment, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

A liquid crystal alignment agent for photo-alignment comprises a polymer component (A) and a solvent (B). The polymer component (A) incluseds a first polymer (A1) selected from the group consisting of at least one of a polyimide precursor and an imidization polymer made from the polyimide precursor. The polyimide precursor contains a structure represented by formula (I). In the formula (I), X ¹、X ²、X ³及Y ¹are defined according to the specification and the claims.

Description

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

The present invention relates to a liquid crystal alignment agent for photo-alignment method and its application, and particularly to a liquid crystal alignment agent comprising a first polymer and its application, wherein the first polymer is selected from at least one of the group consisting of a polyimide precursor having a structure shown in formula (I) and an imidized polymer formed by the polyimide precursor.

Based on the driving force of liquid crystal molecules, there are currently two types of liquid crystal displays: longitudinal electric field driven liquid crystal displays and transverse electric field driven liquid crystal displays. Examples of such liquid crystal displays driven by longitudinal electric fields are twisted nematic (TN) type liquid crystal displays and vertical alignment (VA) type liquid crystal displays. Examples of such liquid crystal displays driven by transverse electric fields are in-plane switching (IPS) type liquid crystal displays and fringe field switching (FFS) type liquid crystal displays.

In the above-mentioned liquid crystal displays, the alignment treatment method using friction is currently used to make the liquid crystal alignment film have grooves that can align the liquid crystal molecules along a certain direction. The most popular alignment treatment method in the industry is to rub the liquid crystal alignment film formed by polyamide polymer and/or polyimide polymer obtained by imidization of polyamide polymer with cotton, nylon or polyester cloth in one direction. The alignment treatment method using friction is a simple, high-productivity and industrially useful method. However, with the increasing performance requirements for liquid crystal displays, finer image quality and larger sizes, in order to avoid various problems such as damage to the liquid crystal alignment film caused by dust and static electricity generated by friction processing and alignment non-uniformity, the photo-alignment method that gives the liquid crystal alignment film the ability to have photo-alignment by irradiating polarized radiation has emerged, such as the photo-alignment method disclosed in Japanese Patent Laid-Open No. H09297313.

However, although the liquid crystal alignment film used in the optical alignment method can avoid the problems caused by the alignment treatment using the friction method, the liquid crystal in the liquid crystal display using the liquid crystal alignment film used in the optical alignment method is not easy to return to the initial tilt angle after driving, and there is a problem of high brightness change rate after driving, which makes it unable to meet the application requirements.

Therefore, the first purpose of the present invention is to provide a liquid crystal alignment agent for photoalignment.

Therefore, the liquid crystal alignment agent used in the photo-alignment method of the present invention comprises a polymer component (A) and a solvent (B). The polymer component (A) comprises a first polymer (A1). The first polymer (A1) is selected from at least one of the group consisting of a polyimide precursor and an imidized polymer formed by the polyimide precursor, and the polyimide precursor of the first polymer (A) comprises a structure shown in formula (I),

X¹¹、X¹²、X¹³與X¹⁴分別獨立地表示氫、鹵素、碳數1至6的烷基、碳數2至6的烯基、碳數2至6的炔基、碳數為1至6且含有氟原子的一價有機基，或苯基，X¹⁵與X¹⁶分別獨立地表示氫或甲基， X²表示氫或碳數為1至4的烷基，X³表示氫或碳數為1至4的烷基； Y¹表示

，其中，「*」代表鍵結位置，R¹、R²、R³及R⁴分別獨立地表示氫、碳數為1至6的烷基、碳數為1至6的烷氧基，或碳數為1至6的氟烷基，T¹、T²、T³、T⁴、T⁵、T⁶、T⁷及T⁸分別獨立地表示氫或1價基團，m表示1、2或3，n表示1、2或3，t表示1、2或3。 ^X1 represents at least one of the group consisting of the structures represented by formula (I-1) to formula (I-7), wherein "*" represents a bonding position,

^X11 , ^X12 , ^X13 and ^X14 independently represent hydrogen, a halogen, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group; ^X15 and ^X16 independently represent hydrogen or a methyl group; ^X2 represents hydrogen or an alkyl group having 1 to 4 carbon atoms; ^X3 represents hydrogen or an alkyl group having 1 to 4 carbon atoms; ^Y1 represents

, wherein "*" represents a bonding position, R ¹ , R ² , R ³ and R ⁴ each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms, T ¹ , T ² , T ³ , T ⁴ , T ⁵ , T ⁶ , T ⁷ and T ⁸ each independently represent hydrogen or a monovalent group, m represents 1, 2 or 3, n represents 1, 2 or 3, and t represents 1, 2 or 3.

The second purpose of the present invention is to provide a liquid crystal alignment film.

Therefore, the liquid crystal alignment film of the present invention is formed by the liquid crystal alignment agent used in the above-mentioned photo-alignment method.

The third purpose of the present invention is to provide a liquid crystal display element.

Therefore, the liquid crystal display element of the present invention includes: the above-mentioned liquid crystal alignment film.

The effect of the present invention is that: by using a polyimide precursor having a structure shown in formula (I) or/and an imidized polymer formed by the polyimide precursor, a liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention is used in a liquid crystal display element, which can give the liquid crystal display element a low brightness change rate after driving, thereby meeting the application requirements.

The present invention is described in detail below.

<Liquid crystal alignment agent for photo-alignment method>

The liquid crystal alignment agent used in this luminescent alignment method comprises a polymer component (A) and a solvent (B).

[Polymer component (A)]

<First Polymer (A1)>

The first polymer (A1) is selected from at least one of the group consisting of a polyimide precursor formed by reacting a reaction composition comprising a tetracarboxylic dianhydride component (a1) and a diamine component (b1) and an imidized polymer formed by the polyimide precursor. For example, the first polymer (A1) is a polyimide precursor having an imide precursor structure of polyamic acid and polyamic acid ester, or the first polymer (A1) is an imidized polymer (i.e., polyimide) formed by the polyimide precursor, or the first polymer (A1) includes the polyimide precursor and the imidized polymer.

The polyimide precursor of the first polymer (A1) comprises a structure represented by formula (I),

X¹¹、X¹²、X¹³與X¹⁴分別獨立地表示氫、鹵素、碳數1至6的烷基、碳數2至6的烯基、碳數2至6的炔基、碳數為1至6且含有氟原子的一價有機基，或苯基，X¹⁵與X¹⁶分別獨立地表示氫或甲基，X²表示氫或碳數為1至4的烷基，X³表示氫或碳數為1至4的烷基； Y¹表示

，其中，「*」 代表鍵結位置，R¹、R²、R³及R⁴分別獨立地表示氫、碳數為1至6的烷基、碳數為1至6的烷氧基，或碳數為1至6的氟烷基，T¹、T²、T³、T⁴、T⁵、T⁶、T⁷及T⁸分別獨立地表示氫或1價基團，m表示1、2或3，n表示1、2或3，t表示1、2或3。 ^X1 represents at least one of the group consisting of the structures represented by formula (I-1) to formula (I-7), wherein "*" represents a bonding position,

^X11 , ^X12 , ^X13 and ^X14 independently represent hydrogen, a halogen, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group; ^X15 and ^X16 independently represent hydrogen or a methyl group; ^X2 represents hydrogen or an alkyl group having 1 to 4 carbon atoms; ^X3 represents hydrogen or an alkyl group having 1 to 4 carbon atoms; ^Y1 represents

, wherein "*" represents a bonding position, R ¹ , R ² , R ³ and R ⁴ each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms, T ¹ , T ² , T ³ , T ⁴ , T ⁵ , T ⁶ , T ⁷ and T ⁸ each independently represent hydrogen or a monovalent group, m represents 1, 2 or 3, n represents 1, 2 or 3, and t represents 1, 2 or 3.

，其中，在式(Y-1)中，m及t獨立地表示1、2或3，在式(Y-2)中，m及t獨立地表示1、2或3。較佳地，當式(I)所示的結構中的Y¹為式(Y-1)或式(Y-2)時，包含由該液晶配向劑所形成的液晶配向膜的液晶顯示元件具有更低的驅動後亮度變化率。 In some embodiments of the present invention, ^Y1 is

, wherein, in formula (Y-1), m and t independently represent 1, 2 or 3, and in formula (Y-2), m and t independently represent 1, 2 or 3. Preferably, when ^Y1 in the structure shown in formula (I) is formula (Y-1) or formula (Y-2), a liquid crystal display element including a liquid crystal alignment film formed by the liquid crystal alignment agent has a lower brightness change rate after driving.

When the polyimide precursor of the first polymer (A1) does not contain the structure shown in formula (I), the liquid crystal display element including the liquid crystal alignment film formed by the liquid crystal alignment agent has a high brightness change rate after driving.

<Tetracarboxylic dianhydride component (a1)>

The tetracarboxylic dianhydride component (a1) may use tetracarboxylic dianhydride compounds, as well as tetracarboxylic dianhydride derivatives such as tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters, or tetracarboxylic acid dialkyl ester dihalides. The tetracarboxylic dianhydride component (a1) may use a single tetracarboxylic dianhydride compound or its derivatives, or may use a combination of multiple types.

。 In some embodiments of the present invention, the tetracarboxylic dianhydride component (a1) comprises an alicyclic tetracarboxylic dianhydride (a1-1) or a derivative thereof represented by formula (A11), and the alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11) is

.

The alicyclic tetracarboxylic dianhydride (a1-1) or its derivatives shown in formula (A11) may be composed of a single tetracarboxylic dianhydride or its derivatives, or may be composed of a plurality of tetracarboxylic dianhydrides or their derivatives. The alicyclic tetracarboxylic dianhydride (a1-1) shown in formula (A11) is, for example, an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an alicyclic structure. However, none of the four carboxyl groups are bonded to an aromatic ring. Alternatively, it is not necessary to be composed of only an alicyclic structure, and a part of it may have a chain hydrocarbon structure or an aromatic ring structure. The aromatic tetracarboxylic dianhydride is, for example, an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an aromatic ring. However, the aromatic tetracarboxylic dianhydride does not need to be composed of only an aromatic ring structure, and a part of it may have a chain hydrocarbon structure or an alicyclic structure. The non-cyclic aliphatic tetracarboxylic dianhydride may be, for example, an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. However, the non-cyclic aliphatic tetracarboxylic dianhydride does not need to be composed of only a chain hydrocarbon structure, and a part of it may have an alicyclic structure or an aromatic ring structure.

In formula (A11), ^X1 is at least one selected from the group consisting of structures represented by formula (I-1) to formula (I-7), and "*" represents a bonding position.

In formula (I-1), ^X11 , ^X12 , ^X13 and ^X14 each independently represent hydrogen, a halogen, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. In formula (I-7), ^X15 and ^X16 each independently represent hydrogen or a methyl group.

In some embodiments of the present invention, the structure represented by formula (I-1) of ^X1 is selected from the structures represented by formula (I-1-1) to (I-1-6),

Preferably, the structure represented by formula (I-1) of ^X1 is the structure represented by formula (I-1-1). When the structure represented by formula (I-1) of ^X1 is the structure represented by formula (I-1-1), the liquid crystal display element including the liquid crystal alignment film formed by the liquid crystal alignment agent has a lower brightness change rate after driving.

In some embodiments of the present invention, based on the total amount of the tetracarboxylic dianhydride component (a1) being 100 mol, the amount of the alicyclic tetracarboxylic dianhydride (a1-1) represented by the formula (A11) is 30 mol to 100 mol, preferably 40 mol to 100 mol, and more preferably 50 mol to 100 mol.

When the tetracarboxylic dianhydride component (a1) does not contain the alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11), the liquid crystal display element including the liquid crystal alignment film formed by the liquid crystal alignment agent has a high brightness change rate after driving.

In some embodiments of the present invention, the tetracarboxylic dianhydride component (a1) also contains other tetracarboxylic dianhydrides (a1-2).

。 In some embodiments of the present invention, the other tetracarboxylic dianhydride (a1-2) comprises a tetracarboxylic dianhydride compound represented by formula (A12) or a derivative thereof, wherein the tetracarboxylic dianhydride compound represented by formula (A12) is

.

In formula (A12), X ^1' represents a structure represented by formula (A12-1) to formula (A12-32), wherein "*" represents a bonding position,

In formula (A12-1), a1 is 1 to 12. In formula (A12-5), X ^11' represents a single bond, -O-, -CO-, -COO-, a phenylene group, a sulfonyl group or an amide group, and a1 represents 0 or 1. In formula (A12-6), X ^11' and X ^12' each independently represent a single bond, -O-, -CO-, -COO-, a phenylene group, a sulfonyl group or an amide group, and a plurality of X ^12' are the same or different, and a1 represents 0 or 1. In formula (A12-11), a1 represents 2 to 6. In formula (A12-13), a1 represents 1 to 2. In formula (A12-14), X ^13' independently represents hydrogen, a halogen, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group containing fluorine and having 1 to 6 carbon atoms, or a phenyl group, and a plurality of X ^13' groups are the same or different. From the viewpoint of liquid crystal alignment, preferably, X ^13' represents hydrogen, a halogen, a methyl group or an ethyl group, and more preferably, represents hydrogen or a methyl group.

、

、

、

In some embodiments of the present invention, formula (A12-5) and formula (A12-6) include but are not limited to

,

,

,

The other tetracarboxylic dianhydride (a1-2) can be used alone or in combination. In some embodiments of the present invention, based on the total amount of the tetracarboxylic dianhydride component (a1) being 100 mol, the amount of the other tetracarboxylic dianhydride (a1-2) used is 0 mol to 70 mol, preferably 0 mol to 60 mol, and more preferably 0 mol to 50 mol.

<Diamine component (b1)>

In some embodiments of the present invention, the diamine component (b1) comprises a diamine compound (b1-1).

，其中，「*」代表鍵結位置，R¹、R²、R³及R⁴分別獨立地表示氫、碳數為1至6的烷基、碳數為1至6的烷氧基，或碳數為1至6的氟烷基，T¹、T²、T³、T⁴、T⁵、T⁶、T⁷及T⁸分別獨立地表示氫或1價基團，m表示1、2或3，n表示1、2或3，t表示1、2或3。 The diamine compound (b1-1) is a diamine compound represented by formula (A21), and the diamine compound represented by formula (A21) is

, wherein "*" represents a bonding position, R ¹ , R ² , R ³ and R ⁴ each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms, T ¹ , T ² , T ³ , T ⁴ , T ⁵ , T ⁶ , T ⁷ and T ⁸ each independently represent hydrogen or a monovalent group, m represents 1, 2 or 3, n represents 1, 2 or 3, and t represents 1, 2 or 3.

From the perspective of liquid crystal alignment, preferably, in the diamine compound represented by formula (A21), m and t independently represent 1 or 2.

In the diamine compound represented by formula (A21), ^T1 , ^T2 , ^T3 , ^T4 , ^T5 , ^T6 , ^T7 and ^T8 each independently represent hydrogen or a monovalent group. The monovalent group is, for example, a halogen, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group having 1 to 3 carbon atoms, a cyano group, or a nitro group. Preferably, the monovalent group is selected from a halogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, or a fluoroalkoxy group having 1 to 3 carbon atoms. In some embodiments of the present invention, T ¹ , T ² , T ³ , T ⁴ , T ⁵ , T ⁶ , T ⁷ and T ⁸ are all hydrogen.

In the diamine compound represented by the formula (A21), R ¹ , R ² , R ³ and R ⁴ each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms is, for example, a linear alkyl group having 1 to 6 carbon atoms, or a branched alkyl group having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms is, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, an n-hexyl group, or an isohexyl group.

The fluoroalkyl group with 1 to 6 carbon atoms is formed by replacing at least one hydrogen atom in the alkyl group with 1 to 6 carbon atoms with fluorine. The alkoxy group with 1 to 6 carbon atoms is formed by bonding the alkyl group with 1 to 6 carbon atoms with an oxygen atom. Examples of the alkoxy group with 1 to 6 carbon atoms include methoxy and ethoxy groups.

In the diamine compound represented by the formula (A21), n represents 1, 2 or 3. Preferably, n represents 1 or 2.

In some embodiments of the present invention, preferably, the diamine compound represented by formula (A21) is, for example, a diamine compound represented by formula (A21-1) to (A21-2),

In the diamine compounds represented by the formulae (A21-1) and (A21-2), ^T1 , ^T2 , ^T3 , ^T4 , ^T5 , ^T6 , T7 and ^T8 are independently hydrogen or a monovalent group. The monovalent group is, for example, a halogen, an alkyl group having 1 to 3 carbon atoms ^, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group having 1 to 3 carbon atoms, a cyano group, or a nitro group. Preferably, ^T1 , ^T2 , ^T3 , ^T4 , ^T5 , ^T6 , ^T7 and ^T8 are all hydrogen.

The diamine compound (b1-1) can be used alone or in combination. In some embodiments of the present invention, based on the total amount of the diamine component (b1) being 100 mol, the amount of the diamine compound (b1-1) used is 10 mol to 70 mol, preferably 15 mol to 60 mol, and more preferably 20 mol to 50 mol.

When the diamine component (b1) does not contain the diamine compound (b1-1) represented by formula (A21), the liquid crystal display element including the liquid crystal alignment film formed by the liquid crystal alignment agent has a high brightness change rate after driving.

When the diamine component (b1) comprises the diamine compound represented by formula (A21-1) to (A21-2), the liquid crystal display element comprising the liquid crystal alignment film formed by the liquid crystal alignment agent has a lower brightness change rate after driving.

In some embodiments of the present invention, the diamine component (b1) further comprises a diamine compound (b1-2), and the diamine compound (b1-2) is a diamine compound represented by formula (A22-1) to formula (A22-2),

In formula (A22-1), Y ³¹ represents a divalent organic group represented by formula (A22-3), and a plurality of Y ³² each independently represents hydrogen or an alkyl group having 1 to 6 carbon atoms. In formula (A22-2), a plurality of Y ³³ each independently represents a divalent organic group represented by formula (A22-3'),

In the divalent organic group represented by formula (A22-3), Ar independently represents a divalent benzene ring, biphenyl structure or naphthyl ring, and the hydrogen atom of the benzene ring, biphenyl structure or naphthyl ring may be substituted by a monovalent substituent group or may not be substituted; Y ^31' represents -(CH ₂ ) _n -, n represents an integer from 2 to 18, and at least one -CH ₂ - in -(CH ₂ ) _n - may be substituted by -O-, -C(=O)- or -OC(=O)- or may not be substituted; p1 represents 0 or 1; "*" represents a bonding position.

In the divalent organic group represented by formula (A22-3'), Ar' independently represents a divalent benzene ring or a biphenyl structure, and the hydrogen atom of the benzene ring or the biphenyl structure may be substituted by a monovalent substituent group or may not be substituted; Y ^33' represents -(CH ₂ ) _n -, n represents an integer from 2 to 18, and at least one -CH ₂ - in -(CH ₂ ) _n - may be substituted by -O-, -C(=O)- or -OC(=O)- or may not be substituted; p2 represents 0 or 1; "*" represents a bonding position.

In the divalent organic group represented by formula (A22-3) and the divalent organic group represented by formula (A22-3'), the monovalent substituent group of the benzene ring, biphenyl structure, or naphthyl ring is, for example, a halogen, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkenyl group having 2 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group having 1 to 10 carbon atoms, a cyano group, or a nitro group.

From the viewpoint of improving the liquid crystal alignment, preferably, the divalent organic group represented by formula (A22-3) is a group represented by formula (A22-3-1) to formula (A22-3-16), wherein "*" represents a bonding position,

In formula (A22-3-1), m is 0 to 1, and n is 1 to 6. In formula (A22-3-2), n is 1 to 6. In formula (A22-3-3), n is 2 to 6. In formula (A22-3-4), n is 1 to 6. In formula (A22-3-5), n is 1 to 6. In formula (A22-3-6), n is 2 to 6. In formula (A22-3-7), n is 1 to 6. In formula (A22-3-8), n is 1 to 6. In formula (A22-3-9), n is 2 to 6. In formula (A22-3-10), m is 1 to 3, and n is 1 to 4. In formula (A22-3-11), n is 1 to 6. In formula (A22-3-12), n is 1 to 6. In formula (A22-3-13), m is 0 to 1, and n is 1 to 6. In formula (A22-3-14), m is 1 to 3, and n is 1 to 4.

From the perspective of improving the alignment of liquid crystals, preferably, the divalent organic group represented by formula (A22-3') is a group represented by formula (A22-3-7) to formula (A22-3-16).

When the diamine compound (b1-2) contains a diamine compound represented by a plurality of formulas (A22-1), preferably, Y ³¹ in formula (A22-1) represents a diamine compound of formula (A22-3-1) to formula (A22-3-14) and Y ³¹ in formula (A22-1) represents a combination of diamine compounds of formula (A22-3-15) to formula (A22-3-16).

In some embodiments of the present invention, the diamine compound represented by formula (A22-2) is, for example but not limited to, the diamine compounds represented by formula (A22-2-1) to formula (A22-2-5),

In formula (A22-2-1), m is 1 to 6, and n is 1 to 6. In formula (A22-2-2), m is 1 to 6, and n is 1 to 6. In formula (A22-2-3), m is 2 to 6, and n is 2 to 6.

The diamine compound (b1-2) can be used alone or in combination. In some embodiments of the present invention, based on the total amount of the diamine component (b1) being 100 mol, the amount of the diamine compound (b1-2) used is 20 mol to 90 mol, preferably 25 mol to 80 mol, and more preferably 30 mol to 70 mol.

In some embodiments of the present invention, the diamine component (b1) also contains a diamine compound (b1-3) having a -N(D)- group.

From the viewpoint of improving the voltage retention rate of the liquid crystal display element, the molecular structure of the first polymer (A1) may selectively have a -N(D)- group (where D represents a carbamate-based protective group). The first polymer (A1) having a -N(D)- group can be obtained by using a monomer having a -N(D)- group as at least a part of the reaction raw material, or by using a monomer having a -N(D)- group as the following end-capping agent. In some specific examples, the monomer having a -N(D)- group is, for example, a diamine compound (b1-3) having a -N(D)- group. For example, the carbamate-based protective group is, for example, but not limited to, tert-butyloxycarbonyl (Boc for short) or 9-fluorenylmethoxycarbonyl.

Preferably, the diamine compound (b1-3) having a -N(D)- group includes a diamine compound having at least one aromatic group (e.g., a benzene ring). More preferably, the diamine compound (b1-3) having a -N(D)- group includes a diamine compound having at least one aromatic group and a residue other than the substituent (D) having a carbon number of 6 to 30. In some specific examples, the diamine compound (b1-3) having a -N(D)- group is, for example but not limited to, a diamine compound represented by formula (A23-1) to formula (A23-10),

In formula (A23-1), n is 1 to 6. In formula (A23-2), n is 1 to 6. In formula (A23-4), m is 1 to 6, and n is 1 to 6. In formula (A23-7), m is 1 to 6, and n is 1 to 6. In formula (A23-9), n is 1 to 6.

The diamine compound (b1-3) having a -N(D)- group can be used alone or in combination. In some embodiments of the present invention, based on the total amount of the diamine component (b1) being 100 mol, the amount of the diamine compound (b1-3) having a -N(D)- group is 2 mol to 60 mol, preferably 10 mol to 50 mol, and more preferably 15 mol to 40 mol.

In some embodiments of the present invention, the diamine component (b1) also contains other diamine compounds (b1-4).

唑啉結構的二胺化合物等。 The other diamine compounds (b1-4) include, but are not limited to, diamine compounds having a photoalignment group, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, diamine compounds having a carboxyl group, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, ketone, 1,4-bis(4-aminobenzyl)benzene, 4,4'-diaminodiphenyl ether, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-dihydroindene-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine, a diamine compound having a urea bond, a diamine compound having an amide bond, a diamine compound having a photopolymerizable group at the end, a diamine compound having a siloxane bond, or

Diamine compounds with oxazoline structure, etc.

The diamine compound having a photo-alignment group is, for example but not limited to, 4,4'-diaminoazobenzene, or diamine compounds represented by formula (A24-1) to formula (A24-3),

The diamine compound having a carboxyl group is, for example but not limited to, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, or diamine compounds represented by formula (A24-4) to formula (A24-7),

In formula (A24-4), ^Y51 represents a single bond, _-CH2- , _-C2H4- , -C( _CH3 ) _2- , _-CF2- , -C( _CF3 ) _2- , -O-, -CO-, -NH-, _-N ( _CH3 )-, -CONH-, -NHCO-, -CH2O- _{, -OCH2-} , -COO-, -OCO-, -CON( _CH3 )- or -N( _CH3 )CO-; m1 and m2 each independently represent an integer from 0 to 4, and (m1+m2) represents an integer from 1 to 4. In formula (A24-5), m3 and m4 each independently represent an integer from 1 to 5. In formula (A24-6), ^Y52 represents a linear or branched alkyl group having 1 to 5 carbon atoms; m5 represents an integer from 1 to 5. In formula (A24-7) _, ^Y53 and ^Y54 each independently represent a single bond, _-CH2- , _-C2H4- , -C( _CH3 ) _2- , -CF2-, -C( _CF3 ) _2- , -O-, _-CO- , -NH-, -N _{( CH3} )-, -CONH-, -NHCO-, -CH2O-, _-OCH2- , -COO-, -OCO-, -CON( _CH3 )- or -N( _CH3 )CO-; m6 represents an integer from 1 to 4.

The diamine compound having a urea bond is, for example but not limited to, the diamine compounds represented by formula (A24-8) to formula (A24-10),

In formula (A23-8), n1 is 0 to 6, and n2 is 1 to 6. In formula (A23-9), n1 is 1 to 6, and n2 is 1 to 6. In formula (A23-10), n is 1 to 6.

The diamine compound having an amide bond is, for example but not limited to, the diamine compound having an amide bond represented by formula (A24-11) to formula (A24-13):

In formula (A24-12), n is 1 to 6. In formula (A23-13), n1 is 1 to 6, and n2 is 1 to 6.

The diamine compound having a photopolymerizable group at the end includes, but is not limited to, 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallylaniline.

The diamine compound having a siloxane bond is, for example but not limited to, 3-bis(3-aminopropyl)-tetramethyldisiloxane.

唑啉結構的二胺化合物例如但不限於式(A24-14)至式(A24-15)所示的二胺化合物等，

The tool

The diamine compound of oxazoline structure is, for example, but not limited to, the diamine compound represented by formula (A24-14) to formula (A24-15),

The other diamine compound (b1-4) can be used alone or in combination. In some embodiments of the present invention, based on the total amount of the diamine component (b1) being 100 mol, the amount of the other diamine compound (b1-4) used is 0 mol to 65 mol, preferably 0 mol to 50 mol, and more preferably 0 mol to 35 mol.

<Second Polymer (A2)>

In some embodiments of the present invention, the polymer component (A) also includes a second polymer (A2).

The second polymer (A2) is selected from at least one of the group consisting of a polyimide precursor formed by reacting a reaction composition comprising a tetracarboxylic dianhydride component (a2) and a diamine component (b2) and an imidized polymer formed by the polyimide precursor, wherein the diamine component (b2) of the second polymer (A2) does not contain the diamine compound (b1-1) in the diamine component (b1) of the first polymer (A1). For example, the second polymer (A2) is a polyimide precursor having an imide precursor structure of polyamic acid and polyamic acid ester, or the second polymer (A2) is an imidized polymer (i.e., polyimide) formed by the polyimide precursor, or the second polymer (A2) includes the polyimide precursor and the imidized polymer. The second polymer (A2) can be used alone or in combination.

In some embodiments of the present invention, the weight ratio of the first polymer (A1) to the second polymer (A2) (i.e., the mass ratio of the first polymer (A1)/the second polymer (A2)) is 10/90 to 90/10, preferably 20/80 to 90/10, and more preferably 20/80 to 80/20.

<Tetracarboxylic dianhydride component (a2)>

The tetracarboxylic dianhydride component (a2) is, for example, but not limited to, a non-cyclic aliphatic tetracarboxylic dianhydride compound, alicyclic tetracarboxylic dianhydride compound, aromatic tetracarboxylic dianhydride compound, or derivatives of these compounds. The non-cyclic aliphatic tetracarboxylic dianhydride compound, the alicyclic tetracarboxylic dianhydride compound and the aromatic tetracarboxylic dianhydride compound are, for example, the tetracarboxylic dianhydride compound in the first polymer (A1). Preferably, the tetracarboxylic dianhydride component (a2) comprises an alicyclic tetracarboxylic dianhydride or a derivative thereof as shown in formula (A11), or a tetracarboxylic dianhydride compound or a derivative thereof having a structure as shown in formula (A12) above and X ^1' representing formula (A12-1) to formula (A12-6). The tetracarboxylic dianhydride component (a2) can be used alone or in combination of a plurality of types.

Preferably, the tetracarboxylic dianhydride component (a2) comprises a tetracarboxylic dianhydride compound (a2-1) having a structure represented by formula (A12) and X ^1' having a structure represented by formula (III).

In formula (III), Z ¹¹ represents a single bond, and “*” represents a bonding position.

The tetracarboxylic dianhydride compound (a2-1) can be used alone or in combination of two or more.

More preferably, the tetracarboxylic dianhydride component (a2) comprises a tetracarboxylic dianhydride compound represented by formula (IV),

When the tetracarboxylic dianhydride component (a2) includes a tetracarboxylic dianhydride compound represented by formula (IV), a liquid crystal display element including a liquid crystal alignment film formed by the liquid crystal alignment agent has a lower brightness change rate after driving.

In some embodiments of the present invention, based on the total amount of the tetracarboxylic dianhydride component (a2) being 100 mol, the amount of the tetracarboxylic dianhydride compound (a2-1) used is 30 mol to 100 mol, preferably 40 mol to 100 mol, and more preferably 50 mol to 100 mol.

<Diamine component (b2)>

The diamine component (b2) is, for example but not limited to, the diamine component (b1) of the first polymer (A1), or a diamine compound (b2-1) having a nitrogen atom-containing structure, but the diamine component (b2) does not contain the above diamine compound (b1-1). The diamine component (b2) can be used alone or in combination of multiple types.

<Diamine compound having a nitrogen atom-containing structure (b2-1)>

The nitrogen-containing atom structure in the diamine compound (b2-1) having a nitrogen-containing atom structure is selected from at least one of the group consisting of a nitrogen-containing heterocyclic ring, a diamine group, and a tertiary amine group.

、吡

、吲哚、苯并咪唑、嘌呤、喹啉、異喹啉、

啶、喹

啉、呔

、三

、咔唑、吖啶、哌啶、哌

、吡咯啶或六亞甲基亞胺等。較佳地，該含氮原子的雜環為吡啶、嘧啶、吡

、哌啶、哌

、喹啉、咔唑或吖啶。 The nitrogen-containing heterocyclic ring of the diamine compound (b2-1) having a nitrogen-containing structure includes, but is not limited to, pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, tantalum,

, pyridine

, indole, benzimidazole, purine, quinoline, isoquinoline,

Pyridine, quinone

Phylin

,three

, carbazole, acridine, piperidine, piperidine

, pyrrolidine or hexamethyleneimine, etc. Preferably, the heterocyclic ring containing a nitrogen atom is pyridine, pyrimidine, pyrrolidine or hexamethyleneimine.

, piperidine, piperidine

, quinoline, carbazole or acridine.

The nitrogen-containing atom structure in the diamine compound (b2-1) having a nitrogen-containing atom structure is a diamine group and a tertiary amine group represented by formula (B21),

In formula (B21), Z represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group, or an aryl group; "*" represents a bonding position.

The alkyl group with a carbon number of 1 to 10 is, for example, but not limited to, methyl, ethyl or propyl. The cycloalkyl group is, for example, but not limited to, cyclohexyl. The aryl group is, for example, but not limited to, phenyl or toluene. Preferably, Z is hydrogen or methyl.

、3,6-二胺基吖啶、N-乙基-3,6-二胺基咔唑、N-苯基-3,6-二胺基咔唑、式(B21-1)至式(B21-8)所示的二胺化合物，或式(B21-9)至式(B21-26)所示的二胺化合物，

The diamine compound (b2-1) having a nitrogen atom-containing structure includes, but is not limited to, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperidin

, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, diamine compounds represented by formula (B21-1) to (B21-8), or diamine compounds represented by formula (B21-9) to (B21-26),

In formula (B21-5), n represents 1 to 4. In formula (B21-6), n represents 1 to 4. The diamine compound (b2-1) having a nitrogen atom-containing structure can be used alone or in combination of two or more.

When the diamine component (b2) contains the diamine compound (b2-1) having a nitrogen atom-containing structure, the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has a lower brightness change rate after driving.

In some embodiments of the present invention, based on the total amount of the diamine component (b2) being 100 mol, the amount of the diamine compound (b2-1) having a nitrogen atom-containing structure is 15 mol to 100 mol, preferably 20 mol to 90 mol, and more preferably 25 mol to 80 mol.

<Method for preparing the first polymer (A1) and the second polymer (A2)>

、HO-CH₂-CH₂-O-Z²式(D-2)、HO-CH₂-CH₂-O-CH₂-CH₂-O-Z³式(D-3)。 The first polymer (A1) and the second polymer (A2) can be produced by reacting the above-mentioned diamine component and tetracarboxylic dianhydride component in a solvent (polycondensation). When a portion of the first polymer (A1) and the second polymer (A2) has an acylamidic acid structure, for example, the tetracarboxylic dianhydride component is reacted with the diamine component to obtain a polymer having an acylamidic acid structure (i.e., polyacylamidic acid). The solvent is not particularly limited, and only needs to be able to dissolve the formed polymer. For example, the solvent is, for example, but not limited to, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide or 1,3-dimethyl-2-imidazolidinone. In some embodiments of the present invention, when the solvent solubility of the polymer is high, the solvent is, for example, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a solvent as shown in formula (D-1) to formula (D-3),

, HO-CH ₂ -CH ₂ -OZ ² formula (D-2), HO-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -OZ ³ formula (D-3).

In formula (D-1), Z ¹ represents an alkyl group having 1 to 3 carbon atoms. In formula (D-2), Z ² represents an alkyl group having 1 to 3 carbon atoms. In formula (D-3), Z ³ represents an alkyl group having 1 to 4 carbon atoms.

The solvent can be used alone or in combination. Secondly, even if it is a solvent that cannot dissolve the polymer, the solvent that cannot dissolve the polymer can still be mixed with the above-mentioned solvent within the range that the generated polymer will not precipitate. When the diamine component and the tetracarboxylic dianhydride component react in the solvent, the reaction can be carried out at any concentration. Preferably, the concentration of the reaction is 1wt% to 50wt%, and more preferably, 5wt% to 30wt%. The reaction can also be carried out at a high concentration initially, and then additional solvent is added. When the reaction is carried out, preferably, the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic dianhydride component is 0.8 to 1.2. Similar to the general polycondensation reaction, the closer the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic dianhydride component is to 1.0, the greater the molecular weight of the first polymer (A1) or the second polymer (A2) formed.

The polymer having an acylamidoester structure can be obtained, for example, by a known method, and the known method is (1) a method of reacting the polyacylamidoester obtained by the above method with an esterifying agent, (2) a method of reacting a tetracarboxylic acid diester compound with a diamine compound, or (3) a method of reacting a tetracarboxylic acid diester dihalide with a diamine compound.

The imidized polymer in the first polymer (A1) or the second polymer (A2) of the liquid crystal alignment agent of the present invention can be obtained, for example, by ring-closing the polymer having an acylamidate structure. In the imidized polymer, the ring-closing rate (also called the imidization rate) of the functional group possessed by the acylamidate group or its derivative does not necessarily need to be 100%, and the imidization rate of the imidized polymer can be arbitrarily adjusted according to the use and/or purpose.

For the method of obtaining the imidized polymer, for example, a solution containing a polymer having an acylate structure is directly heated for thermal imidization, or a catalyst is added to the solution for catalytic imidization. When the thermal imidization is performed in the solution, preferably, the temperature is 100°C to 400°C, more preferably, 120°C to 250°C. When the thermal imidization is performed, preferably, the water generated by the imidization reaction is discharged from the system.

The catalytic imidization is carried out, for example, by adding an alkaline catalyst and an acid anhydride to the solution, preferably, stirring is carried out at -20°C to 250°C, more preferably, at 0°C to 180°C. Preferably, the amount of the alkaline catalyst added is 0.5 to 30 times the molar equivalent of the amide group, more preferably, 2 to 20 times. Preferably, the amount of the acid anhydride added is 1 to 50 times the molar equivalent of the amide group, more preferably, 3 to 30 times. The alkaline catalyst is, for example, but not limited to, pyridine, triethylamine, trimethylamine, tributylamine or trioctylamine. Among them, pyridine is ideal because it has a moderate alkalinity that allows the reaction to proceed. The acid anhydride is, for example, but not limited to, acetic anhydride, trimellitic anhydride, or pyromellitic anhydride. Among them, when acetic anhydride is used, purification after the reaction is easier, so it is more ideal. The imidization rate of the catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature and/or reaction time.

When the imidized polymer is recovered from the imidized reaction solution, the reaction solution is put into a solvent and precipitated. The solvent used for precipitation is, for example, but not limited to, methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene or water. After filtering and recovering the polymer precipitated in the solvent, it can be dried at normal pressure or reduced pressure, at room temperature or by heating. Alternatively, the polymer recovered by precipitation is dissolved in a solvent and reprecipitated and recovered. This operation is repeated 2 to 10 times to reduce impurities in the polymer. The solvent used can be, for example, alcohols or ketones. If more than three selected solvents are used, the refining efficiency can be further improved, so it is more ideal.

When the solution is prepared into a concentration of 10wt% to 15wt%, the solution viscosity of the first polymer (A1) or the second polymer (A2) of the present invention is not particularly limited. Based on the viewpoint of easier operation, the solution viscosity can be, for example, 10mPa‧s to 1000mPa‧s. The solution viscosity (mPa‧s) of the polymer is a value measured at 25°C using a good solvent for the polymer (e.g., γ-butyrolactone or N-methyl-2-pyrrolidone, etc.) to prepare a polymer solution with a concentration of 10wt% to 15wt%, and using an E-type rotational viscometer.

Preferably, the weight average molecular weight (Mw) of the first polymer (A1) or the second polymer (A2) of the present invention measured by gel permeation chromatography (GPC) in terms of polystyrene is 1,000 to 500,000, more preferably, 2,000 to 500,000. Secondly, preferably, the molecular weight distribution (Mw/Mn) represented by the ratio of Mw to the number average molecular weight (Mn) measured by GPC in terms of polystyrene is 15 or less, more preferably, 10 or less. When the molecular weight of the polymer is within the above molecular weight range, good orientation and stability of the liquid crystal display element can be ensured.

When synthesizing the first polymer (A1) or the second polymer (A2) of the present invention, the tetracarboxylic dianhydride component and the diamine component as described above can be used, and a suitable end-capping agent can be used to synthesize an end-sealed polymer. The end-sealed polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by coating, and improving the sealing properties of the sealant and the liquid crystal alignment film. The end of the first polymer (A1) or the second polymer (A2) of the present invention can be, for example, an amine group, a carboxyl group, an anhydride group, or a derivative thereof. The amine group, the carboxyl group, the anhydride group, or a derivative thereof can be obtained by a general condensation reaction, or by using the following end-capping agent to seal the end. Similarly, the above-mentioned derivatives can be obtained, for example, using the following end-capping agent.

The end-capping agent may be, for example, but not limited to, an acid anhydride, a dicarbonic acid diester compound, a chlorocarbonyl compound, a monoamine compound, or a monoisocyanate compound. The acid anhydride may be, for example, but not limited to, acetic anhydride, maleic anhydride, neddic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-((3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, or 4-ethynylphthalic anhydride. The dicarbonic acid diester compound may be, for example, but not limited to, di-tert-butyl dicarbonate or diallyl dicarbonate. The chlorocarbonyl compound may be, for example, but not limited to, acryloyl chloride, methacryloyl chloride, or nicotinyl chloride. The monoamine compound includes, but is not limited to, aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine or n-octylamine. The monoisocyanate compound includes, but is not limited to, ethyl isocyanate, phenyl isocyanate or naphthyl isocyanate.

The end-capping agent can be used alone or in combination. In some embodiments of the present invention, preferably, based on the total amount of the diamine component being 100 mol parts, the amount of the end-capping agent used is 0.01 mol parts to 20 mol parts, more preferably, 0.01 mol parts to 10 mol parts.

The polymer component (A) of the liquid crystal alignment agent of the present invention may optionally further include other polymers. Such other polymers include, but are not limited to, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivatives, or poly(meth)acrylates, etc.

[Solvent (B)]

From the perspective of forming a uniform film, the liquid crystal alignment agent takes the form of a coating liquid to produce a liquid crystal alignment film. Preferably, the liquid crystal alignment agent of the present invention is a coating liquid containing a polymer component (A) and a solvent (B). Among them, based on the set coating thickness to be formed, the concentration of the polymer component (A) in the liquid crystal alignment agent can be appropriately changed. From the perspective of forming a uniform and defect-free coating, preferably, the concentration of the polymer component (A) in the liquid crystal alignment agent is greater than 1wt%. From the perspective of the storage stability of the solution, preferably, the concentration of the polymer component (A) in the liquid crystal alignment agent is less than 10wt%. The ideal concentration of the polymer component (A) is 2wt% to 8wt%. The content of the polymer component (A) in the liquid crystal alignment agent can be appropriately changed by the coating method of the liquid crystal alignment agent and/or the film thickness of the desired liquid crystal alignment film, preferably, it is 2wt% to 10wt%, more preferably, it is 3wt% to 8wt%.

The solvent (B) in the liquid crystal alignment agent is, for example, an organic solvent, and the solvent (B) is not particularly limited, and only needs to be able to uniformly dissolve the polymer component (A). The solvent (B) For example, but not limited to, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionyl Amine, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone or N-cyclohexyl-2-pyrrolidone, etc., and the above solvents are also called good solvents. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide or γ-butyrolactone is preferred. In some embodiments of the present invention, based on the total amount of solvent (B) in the liquid crystal alignment agent being 100wt%, the amount of good solvent used is 20wt% to 99wt%, preferably 20wt% to 90wt%, and more preferably 30wt% to 80wt%.

Secondly, preferably, the solvent (B) in the liquid crystal alignment agent includes the above-mentioned good solvent and a poor solvent that can improve the coating property of the liquid crystal alignment agent and the surface smoothness of the coating film. Preferably, based on the total amount of the solvent (B) in the liquid crystal alignment agent being 100wt%, the usage amount of the poor solvent is 1wt% to 80wt%, more preferably, 10wt% to 80wt%, and even more preferably, 20wt% to 70wt%. The type and usage amount of the poor solvent can be appropriately selected according to the coating device, coating conditions and/or coating environment of the liquid crystal alignment agent.

The poor solvent includes, but is not limited to, diisopropyl ether, diisobutyl ether, diisobutyl methanol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethyl carbonate, ethylene glycol monobutyl ether (butyl celoxylate), ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)- 2-Propanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, or diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

Preferably, the anhydrous solvent is diisobutyl carbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, or diisobutyl ketone, etc.

Preferably, the solvent combination of good solvent and poor solvent is, for example, but not limited to, N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-dimethyl lactamide and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone and Ethylene glycol monobutyl ether acetate; N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether; N,N-dimethyl lactamide and ethylene glycol monobutyl ether; N,N-dimethyl lactamide and propylene glycol diacetate; N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether; N,N-dimethyl lactamide and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-Hydroxy-4-methyl-2-pentanone and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol diacetate alcohol monobutyl ether and diisopropyl ether; N-methyl -2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl carbinol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and propylene glycol diacetate; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and diisobutyl ketone; N-ethyl-2-pyrrolidone, γ-butyrolactone and diisobutyl ketone; or N-ethyl-2-pyrrolidone, N,N-dimethyl lactamide and diisobutyl ketone, etc.

The solvent (B) can be used alone or in combination. In some embodiments of the present invention, based on the total amount of the polymer component (A) being 100 parts by weight, the amount of the solvent (B) used is 800 parts by weight to 4000 parts by weight, preferably 900 parts by weight to 3500 parts by weight, and more preferably 1000 parts by weight to 3000 parts by weight.

The liquid crystal alignment agent of the present invention also includes additives. The additives include, but are not limited to, adhesion aids for improving the adhesion between the liquid crystal alignment film and the substrate or the liquid crystal alignment film and the sealant, cross-linking compounds for improving the strength of the liquid crystal alignment film, compounds for promoting imidization, dielectrics or conductive substances for adjusting the dielectric constant or resistance of the liquid crystal alignment film, etc.

The adhesion promoter is, for example, but not limited to, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-aminopropyl diethoxymethyl silane, 2-aminopropyl trimethoxysilane, 2-aminopropyl triethoxysilane, N-(2-aminoethyl)-3-aminopropyl trimethoxysilane, N-(2-aminoethyl)-3-aminopropyl methyl dimethoxy silane, 3-ureidopropyl trimethoxysilane, 3-ureidopropyl triethoxysilane, N-ethoxycarbonyl-3-aminopropyl trimethoxysilane, N-ethoxycarbonyl-3-aminopropyl triethoxysilane, N-triethoxysilylpropyl triethyl triamine, N-trimethoxysilylpropyl triethyl triamine, vinyl trimethoxy Silane, vinyl triethoxysilane, 2-(3,4-epoxyhexyl)ethyl trimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane Silane coupling agents such as methoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyldiethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-acryloxypropyl trimethoxysilane, tris(3-trimethoxysilylpropyl) isocyanurate, or 3-isocyanate propyl triethoxysilane. When using a bonding aid, based on the viewpoint of exhibiting good resistance to AC afterimage, preferably, relative to the total amount of the polymer component (A) used in the liquid crystal alignment agent is 100 parts by weight, the amount of the bonding aid used is 0.1 to 30 parts by weight, more preferably, 0.1 to 20 parts by weight.

From the viewpoint of exhibiting good resistance to AC afterimage and effectively improving film strength, the crosslinking compound is a compound having an ethylene oxide group, a propylene oxide group, at least one group selected from the group consisting of a group represented by formula (E1) and a group represented by formula (E2), or a compound selected from the compound represented by formula (E3),

In formula (E1), ^G1 and ^G2 each independently represent hydrogen, an alkyl group having 1 to 3 carbon atoms, or -CH2 _- OH. In formula (E2), ^G3 represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. ^G4 represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. In formula (E3), ^G5 represents a (g1+g2)-valent organic group containing an aromatic ring. ^G6 represents hydrogen or an alkyl group having 1 to 5 carbon atoms. g1 represents an integer from 1 to 6, and g2 represents an integer from 0 to 4.

In formula (E3), the (g1+g2)-valent organic group having an aromatic ring of ^G5 is, for example, a (g1+g2)-valent aromatic hydrocarbon group having 6 to 30 carbon atoms, a (g1+g2)-valent organic group to which an aromatic hydrocarbon group having 6 to 30 carbon atoms is directly or via a linking group, or a (g1+g2)-valent group having an aromatic heterocyclic ring. The aromatic hydrocarbon is, for example, benzene or naphthalene. The aromatic heterocyclic ring is, for example, the exemplified aromatic heterocyclic ring of the nitrogen atom-containing structure described above. The linking group is, for example, an alkylene group having 1 to 10 carbon atoms or a group from which a hydrogen atom is removed, or a divalent or trivalent cyclohexane. Any hydrogen of the alkylene group may also be substituted with an organic group such as a fluorine atom or a trifluoromethyl group. In formula (E3), ^G6 represents an alkyl group having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl or n-pentyl.

The compound having an ethylene oxide group is, for example but not limited to, N,N,N',N'-tetraethylene oxide propyl meta-xylene diamine, 1,3-bis(N,N-diethylene oxide propylaminomethyl)cyclohexane, N,N,N',N'-tetraethylene oxide propyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraethylene oxide propyl-p-phenylenediamine, or nitrogen-containing compounds represented by formula (E4) to formula (E6),

The compound having an propylene oxide group is, for example but not limited to, the compounds represented by formula (E7) to formula (E16),

，其中，「*」代表鍵結位置。於式(E16)中，n表示1至10。 In formula (E1), n represents 1 to 3. In formula (E13), n represents 1 to 3. In formula (E14), n represents 1 to 100. In formula (E15), R represents

, wherein "*" represents a bonding position. In formula (E16), n represents 1 to 10.

The compound having the group represented by formula (E1) includes, but is not limited to, compounds represented by formula (E1-1) to formula (E1-12),

The compound having the group represented by formula (E2) is, for example but not limited to, the compounds represented by formula (E2-1) to formula (E2-4),

In formula (E2-1), n represents 2 to 16. In formula (E2-2), n represents 2 to 16.

The compound having the group represented by formula (E3) is, for example but not limited to, the compounds represented by formula (E3-1) to formula (E3-10),

In the liquid crystal alignment agent of the present invention, preferably, based on the total amount of the polymer component (A) of the liquid crystal alignment agent being 100 parts by weight, the amount of the crosslinking compound used is 0.5 parts by weight to 20 parts by weight. Among them, based on the viewpoint of the crosslinking reaction and the good resistance to AC afterimage, more preferably, the amount of the crosslinking compound used is 1 part by weight to 15 parts by weight.

Preferably, the compound for promoting imidization is a compound having a basic site (e.g., a primary amine group, an aliphatic heterocycle (e.g., a pyrrolidine skeleton), an aromatic heterocycle (e.g., an imidazole ring or an indole ring), or a guanidine group, etc.) (excluding the crosslinking compound and the adhesion promoter), or a compound that generates the basic site when calcined. More preferably, the compound for promoting imidization is a compound that generates the basic site when calcined, for example, an amino acid having a part or all of the basic site of the amino acid being protected. The amino acid is, for example, glycine, alanine, cysteine, methionine, asparagine, glutamine, valine, leucine, phenylalanine, tyrosine, tryptophan, proline, hydroxyproline, arginine, histidine, lysine, or ornithine. For the purpose of promoting the imidization compound, more preferably, a specific example can be listed as N-α-(9-fluorenylmethoxycarbonyl)-N-τ-(tert-butyloxycarbonyl)-L-histidine.

<Liquid crystal alignment film and liquid crystal display element>

The liquid crystal alignment film of the present invention is formed by the above-mentioned liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used as a horizontal alignment type or a vertical alignment type (VA type) liquid crystal alignment film, and is suitable for a liquid crystal alignment film of a horizontal alignment type liquid crystal display element such as an IPS method or a FFS method. The liquid crystal display element of the present invention includes the liquid crystal alignment film. The liquid crystal display element of the present invention can be prepared, for example, by the method of steps (1) to (4), or by the method of steps (1) to (2) and step (4).

Step (1): Apply the liquid crystal alignment agent on the substrate

The liquid crystal alignment agent of the present invention is applied on one side of a substrate provided with a patterned transparent conductive film by using an appropriate coating method such as roller coating, spin coating, printing or inkjet. There is no particular limitation on the substrate, as long as it is a highly transparent substrate. A glass substrate or a silicon nitride substrate can also be used together with a plastic substrate such as an acrylic substrate or a polycarbonate substrate. Secondly, in a reflective liquid crystal display element, when it is only a single-sided substrate, an opaque material such as a silicon wafer can also be used, and the electrode used can also be a light-reflecting material such as aluminum. Furthermore, when making an IPS type or FFS type liquid crystal display element, the comb-tooth type uses an electrode substrate composed of a patterned transparent conductive film or metal film and an opposite substrate without an electrode.

The method of coating the liquid crystal alignment agent on the substrate and forming a film can be screen printing, lithography, flexographic printing, inkjet method or inkjet coating method, etc. Preferably, the film forming method is coating using the inkjet method.

Step (2): calcining the applied liquid crystal alignment agent

Step (2) is a step of calcining the liquid crystal alignment agent coated on the substrate to form a film. After the liquid crystal alignment agent is coated on the substrate, the solvent can be evaporated by heating means such as a hot plate, a heat circulation oven or an infrared oven, or thermal imidization of polyamine or polyamine ester can be performed. The drying and calcining steps after the liquid crystal alignment agent of the present invention has been coated can be selected at any temperature and time, and multiple drying or calcining steps can be performed. The drying temperature can be, for example, 40°C to 180°C. From the perspective of shortening the process, it can be carried out at 40°C to 150°C. There is no particular limitation on the drying time, which may be, for example, 1 minute to 10 minutes or 1 minute to 5 minutes. When the thermal imidization of polyamine or polyamine ester is performed, after the above-mentioned drying step, a calcination step may be further performed at a temperature of, for example, 150°C to 300°C or 150°C to 250°C. There is no particular limitation on the calcination time, which may be, for example, 5 minutes to 40 minutes or 5 minutes to 30 minutes. When the film after calcination is too thin, the reliability of the liquid crystal display element will be reduced. Therefore, preferably, the film thickness is 5nm to 300nm, more preferably, 10nm to 200nm.

Step (3): Perform an alignment treatment on the film obtained in step (2)

Step (3) is to perform an alignment treatment on the film obtained in step (2) as appropriate. That is, in a horizontal alignment type liquid crystal display element such as the IPS mode or the FFS mode, the coating film is subjected to an alignment treatment to give it an alignment capability. On the other hand, in a vertical alignment type liquid crystal display element such as the VA mode or the PSA mode, the formed coating film can be directly used as a liquid crystal alignment film, but the coating film can also be subjected to an alignment treatment to give it an alignment capability. The alignment treatment of the liquid crystal alignment film can be exemplified by a friction treatment method or a photo-alignment treatment method, preferably, a photo-alignment treatment method. The photo-alignment treatment method can be listed as a method of irradiating the surface of the above-mentioned film-like object with radiation that has been deflected in a certain direction, and preferably heating it at a temperature of 150°C to 250°C to give liquid crystal alignment (also known as liquid crystal alignment ability). The radiation can use ultraviolet light or visible light with a wavelength of 100nm to 800nm. Preferably, the radiation is ultraviolet light with a wavelength of 100nm to 400nm, and more preferably, ultraviolet light with a wavelength of 200nm to 400nm.

The radiation exposure amount may be 1mJ/ ^cm2 to 10,000mJ/ ^cm2 , preferably 100mJ/ ^cm2 to 5,000mJ/ ^cm2 , more preferably 100mJ/ ^cm2 to 1500mJ/ ^cm2 , and particularly preferably 100mJ/ ^cm2 to 1000mJ/ ^cm2 . When a general liquid crystal alignment agent is used, the light exposure amount for the alignment treatment is 100mJ/ ^cm2 to 5000mJ/ ^cm2 , but the liquid crystal alignment agent of the present invention can still form a liquid crystal alignment film in which the variation (unevenness) of the liquid crystal alignment in the film surface is effectively suppressed even if the light exposure amount for the alignment treatment is reduced. When irradiating radiation, in order to improve the liquid crystal alignment, the substrate with the film-like object can be heated at 50°C to 250°C while irradiating. The liquid crystal alignment film produced in this way can make the liquid crystal molecules stably align in a certain direction. Secondly, the liquid crystal alignment film irradiated with polarized radiation in the above method can be contact-treated with a solvent, or the liquid crystal alignment film irradiated with radiation can be heated.

There is no particular restriction on the solvent used in the above-mentioned contact treatment, as long as it can dissolve the decomposition products generated from the film after irradiation with radiation. The solvent is, for example, water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl celecoxib, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, or cyclohexyl acetate. Among them, based on the viewpoint of versatility and safety, it is preferred that the solvent is water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate, and more preferably, it is water, 1-methoxy-2-propanol or ethyl lactate. The solvent can be used alone or in combination.

Preferably, the temperature for heat treatment of the radiation-irradiated coating is 50°C to 300°C, more preferably, 120°C to 250°C. Preferably, the heat treatment time is 1 minute to 30 minutes.

Step (4): Making liquid crystal cells

Prepare two liquid crystal alignment film substrates formed as described above, and arrange liquid crystal between the two substrates facing each other. For example, the following two methods can be listed. The first method is to arrange the two substrates facing each other with a gap (cell gap) between them in a way that the liquid crystal alignment films face each other. Then, the periphery of the two substrates is bonded with a sealant, and the liquid crystal composition is injected into the cell gap separated by the substrate surface and the sealant, and the injection hole is sealed after it contacts the film surface.

The second method is called ODF (One Drop Fill) method. A sealant such as a UV-curable sealant is applied to a predetermined position of one of the two substrates on which a liquid crystal alignment film has been formed, and then a liquid crystal composition is dripped onto a plurality of predetermined positions on the surface of the liquid crystal alignment film. Then, the other substrate is bonded with the liquid crystal alignment films facing each other, and the liquid crystal composition is pushed onto the entire surface of the substrate so that it contacts the film surface. Then, ultraviolet light is irradiated onto the entire surface of the substrate to cure the sealant. When any of the above methods is performed, it is preferred that the liquid crystal composition used is further heated to a temperature at which it becomes an isotropic phase, and then slowly cooled to room temperature to remove the flow alignment during liquid crystal filling. Secondly, when the coating is subjected to friction treatment, the two substrates are arranged to face each other with the friction directions of each coating forming a predetermined angle with each other, such as being orthogonal or antiparallel. The sealant may be, for example, an epoxy resin containing a hardener and aluminum oxide balls as spacers. The liquid crystal composition may be, for example, a nematic liquid crystal or a lamellar liquid crystal, preferably a nematic liquid crystal.

If necessary, a polarizing plate can be attached to the outer surface of the liquid crystal cell to obtain a liquid crystal display element. The polarizing plate attached to the outer surface of the liquid crystal cell is, for example, a polarizing film called "H film" that extends and aligns polyvinyl alcohol and absorbs iodine at the same time. The polarizing plate can be a polarizing plate sandwiched by a cellulose acetate protective film, or a polarizing plate composed of the H film itself.

The present invention will be further described with reference to the following embodiments, but it should be understood that the embodiments are only for illustrative purposes and should not be interpreted as limitations on the implementation of the present invention.

Preparation Example 1 Diamine compound represented by formula (A21)

Step (a): 40 mmol of 1,4-bis(chloromethyl)cyclohexane is dissolved in 140 g of dimethylacetamide, and then 84 mmol of 4-nitrophenol and 16.5 g of potassium carbonate are added, and stirred at 90°C for 3 hours to obtain a reaction solution. After the reaction solution is cooled to room temperature, 280 g of pure water is added under stirring to precipitate a crystalline precipitate. The crystalline precipitate is obtained by filtration separation, and then washed with 35 g of pure water, 35 g of tetrahydrofuran and 35 g of acetonitrile in sequence. Then, the product was dried under reduced pressure at 40°C to obtain a dinitro compound.

Step (b): Under a hydrogen atmosphere, 38 mmol of the dinitro compound, 466 g of dimethylformamide and 1.5 g of a carbon-supported platinum catalyst [3% Pt carbon powder (50% water content)] are reacted at 50°C for 18 hours to obtain a reaction solution. Then, the carbon-supported platinum catalyst in the reaction solution is removed using a membrane filter to obtain a filtrate, and then the filtrate is concentrated to obtain a concentrate. 150 g of isopropanol is mixed with the concentrate and stirred at room temperature to precipitate a crystalline precipitate, which is then filtered to obtain the crystalline precipitate. The crystalline precipitate was washed with 75 g of isopropyl alcohol and dried under reduced pressure at 40°C to obtain a diamine compound.

Preparation Examples 2 to 5 Diamine compounds represented by formula (A21)

The preparation methods of Preparation Examples 2 to 5 are similar to those of Preparation Example 1, except that 1,4-bis(chloromethyl)cyclohexane in step (a) of Preparation Example 1 is replaced with other cyclohexane chlorides, and corresponding to Preparation Examples 2 to 5, the other cyclohexane chlorides are 1-(chloromethyl)-4-[4-(chloromethyl)cyclohexyl]cyclohexane, 2-methyl-1,4-bis(chloromethyl)cyclohexane, and 1,4-bis(chloromethyl)cyclohexane. (Chloromethyl)cyclohexane [2-methyl-1,4-bis(chloromethyl)cyclohexane], 1,4-bis(chloroethyl)cyclohexane [1,4-bis(chloroethyl)cyclohexane] and 1-(chloroethyl)-4-[4-(chloroethyl)cyclohexyl]cyclohexane {1-(chloroethyl)-4-[4-(chloroethyl)cyclohexyl]cyclohexane}.

Synthesis Example 1 The first polymer (A1) - polyimide precursor

、0.010莫耳的

及80克的N-甲基-2-吡咯烷酮，並於室溫下攪拌 至溶解。接著，加入0.050莫耳的

及20克的N-甲基-2-吡咯烷酮，並於室溫下反應2小時，獲得反應溶液。將該反應溶液倒入1500毫升的水中，以析出聚合物，然後，進行過濾處理，獲得濾餅，接著，以甲醇清洗該濾餅，然後，進行過濾，其中，以甲醇清洗並過濾，共進行三次。接著，置入真空烘箱中，並以60℃的條件進行乾燥處理，即可製得第一聚合物(A1)。 A 500 ml four-necked conical flask was equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer, and nitrogen was introduced. Then, 0.005 mol of the diamine compound of Preparation Example 1 and 0.035 mol of

, 0.010 mol

and 80 g of N-methyl-2-pyrrolidone and stirred at room temperature until dissolved. Then, add 0.050 mol of

and 20 g of N-methyl-2-pyrrolidone, and react at room temperature for 2 hours to obtain a reaction solution. The reaction solution is poured into 1500 ml of water to precipitate a polymer, and then filtered to obtain a filter cake. Then, the filter cake is washed with methanol and then filtered, wherein the washing and filtering with methanol are performed three times in total. Then, it is placed in a vacuum oven and dried at 60° C. to obtain a first polymer (A1).

Synthesis Examples 2 to 5 and Comparative Synthesis Examples 1 to 3

The preparation methods of Synthesis Examples 2 to 5 and Comparative Synthesis Examples 1 to 3 are roughly similar to Synthesis Example 1, except that the types or amounts of tetracarboxylic dianhydride component (a1) and diamine component (b1) are changed, as shown in Table 1.

Synthesis Example 6 Imidization polymer

、0.010莫耳的

及80克的N-甲基-2-吡咯烷酮，並於室溫下攪拌至溶解。接著，加入0.050莫耳的

及20克的N-甲基-2-吡 咯烷酮，並於室溫下反應6小時，然後，加入97克的N-甲基-2-吡咯烷酮、2.55克的醋酸酐及19.75克的吡啶，升溫至60℃，且持續攪拌2小時，以進行醯亞胺化反應，獲得反應溶液。將該反應溶液倒入1500毫升的水中，以析出聚合物。然後，進行過濾處理，獲得濾餅，接著，以甲醇清洗該濾餅，然後，進行過濾，其中，以甲醇清洗並過濾，共進行三次。接著，置入真空烘箱中，以60℃的條件進行乾燥處理，即可製得第一聚合物(A1)。 A 500 ml four-necked conical flask was equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer, and nitrogen was introduced. Then, 0.005 mol of the diamine compound of Preparation Example 1, 0.035 mol of

, 0.010 mol

and 80 g of N-methyl-2-pyrrolidone and stirred at room temperature until dissolved. Then, add 0.050 mol of

and 20 grams of N-methyl-2-pyrrolidone, and react at room temperature for 6 hours, then add 97 grams of N-methyl-2-pyrrolidone, 2.55 grams of acetic anhydride and 19.75 grams of pyridine, raise the temperature to 60°C, and continue stirring for 2 hours to carry out an imidization reaction to obtain a reaction solution. The reaction solution is poured into 1500 milliliters of water to precipitate a polymer. Then, it is filtered to obtain a filter cake, and then the filter cake is washed with methanol, and then filtered, wherein the washing and filtering with methanol are carried out three times. Then, it is placed in a vacuum oven and dried at 60°C to obtain the first polymer (A1).

Synthesis Example 7 Second polymer (A2)--polyimide precursor

及80克的N-甲基-2-吡咯烷酮，並於室溫下攪拌 至溶解。接著，加入0.05莫耳的

及20克的N-甲基-2-吡咯烷酮，並於室溫下反應2小時，獲得反應溶液。將該反應溶液倒入1500毫升的水中，以析出聚合物，然後，進行過濾處理，獲得濾餅，接著，以甲醇清洗該濾餅，然後，進行過濾，其中，以甲醇清洗並過濾，共進行三次。接著，置入真空烘箱中，並以60℃的條件進行乾燥處理，即可製得第二聚合物(A2)。 A 500 ml four-necked conical flask was equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer, and nitrogen was introduced. Then, 0.05 mol of

and 80 g of N-methyl-2-pyrrolidone and stirred at room temperature until dissolved. Then, add 0.05 mol of

and 20 g of N-methyl-2-pyrrolidone, and react at room temperature for 2 hours to obtain a reaction solution. The reaction solution is poured into 1500 ml of water to precipitate a polymer, and then filtered to obtain a filter cake. Then, the filter cake is washed with methanol and then filtered, wherein the washing and filtering with methanol are performed three times in total. Then, it is placed in a vacuum oven and dried at 60° C. to obtain a second polymer (A2).

Synthesis Examples 8 to 9

The preparation methods of Synthesis Examples 8 to 9 are roughly similar to those of Synthesis Example 7, except that the types or amounts of tetracarboxylic dianhydride component (a2) and diamine component (b2) are changed, as shown in Table 2.

Example 1

100 parts by weight of the first polymer of Synthesis Example 1 and 1200 parts by weight of N-methyl-2-pyrrolidone were stirred and mixed at room temperature to obtain a liquid crystal alignment agent.

Examples 2 to 8

The preparation methods of Examples 2 to 8 are generally similar to those of Example 1, except that the types of the first polymer and the second polymer are changed, as shown in Table 3.

Comparison Example 1

50 parts by weight of the first polymer of Comparative Synthesis Example 1, 50 parts by weight of the second polymer of Synthesis Example 6 and 1200 parts by weight of N-methyl-2-pyrrolidone were stirred and mixed at room temperature to obtain a liquid crystal alignment agent.

Comparison examples 2 to 3

The preparation methods of Comparative Examples 2 to 3 are roughly similar to those of Comparative Example 1, except that the types of the first polymer and the second polymer are changed, as shown in Table 3.

Application example 1: LCD display element

The liquid crystal alignment agent of Example 1 is applied on a pixel electrode of a glass substrate including a pixel electrode by rotational coating, wherein the pixel electrode is an IPS driving electrode having a pair of indium tin oxide (ITO) electrodes (electrode width is 10 μm, electrode spacing is 10 μm, and electrode height is 50 nm), and the pair of ITO electrodes are in a comb-tooth shape, and the comb-tooth portions of each other are configured in a separated and interlocking manner. Then, the glass substrate coated with the liquid crystal alignment agent was dried on a heating plate at 80°C for 3 minutes, and then baked in a hot air circulation oven at 250°C for 30 minutes to obtain a coating with a thickness of 100nm formed on the glass substrate. The coating was irradiated with ultraviolet light with a wavelength of 254nm through a polarizing plate, and then baked in a hot air circulation oven at 250°C for 30 minutes to obtain a first laminate containing a liquid crystal alignment film.

The liquid crystal alignment agent of Example 1 was applied by rotational coating on a glass substrate without pixel electrodes and having columnar spacers with a height of 4 μm. The glass substrate coated with the liquid crystal alignment agent was then dried on a heating plate at 80°C for 3 minutes, and then baked in a hot air circulation oven at 250°C for 30 minutes to obtain a coating with a thickness of 100 nm formed on the glass substrate. The coating was irradiated with ultraviolet light with a wavelength of 254 nm through a polarizing plate, and then baked in a hot air circulation oven at 250°C for 30 minutes to obtain a second laminate including a liquid crystal alignment film.

A sealant is printed on one of the first and second laminates, and then the liquid crystal alignment film of the first laminate is opposite to the liquid crystal alignment film of the second laminate and the alignment direction is 0. The sealant is then cured to obtain a laminate including an injection port and a liquid crystal cell cavity connected to the injection port. Then, liquid crystal MLC-2041 (Merck) is injected into the liquid crystal cell cavity by a reduced pressure injection method, and the injection port is sealed. Then, polarizing plates are attached to the top and bottom surfaces of the laminate perpendicularly to each other to form a liquid crystal display element.

Application examples 2 to 8 and comparative application examples 1 to 3

The preparation methods of application examples 2 to 8 and comparative application examples 1 to 3 are roughly similar to application example 1, except that the liquid crystal alignment agents of application examples 2 to 8 and comparative application examples 1 to 3 are the liquid crystal alignment agents of embodiments 2 to 8 and comparative examples 1 to 3, respectively.

Evaluation items

Brightness change rate after driving: Place the liquid crystal display elements of application examples 1 to 8 and comparison application examples 1 to 3 on a backlight of 10000cd/ ^m2 , and use a brightness meter (model: PR-788) to observe the brightness (L0) in the dark state. Then, drive at 5V AC voltage for 1 hour at room temperature, and observe the brightness (L1) in the dark state when the voltage of the liquid crystal display elements is disconnected. Then, calculate the brightness change rate after driving, and the brightness change rate after driving is [(L1-L0)/L0]×100%. The evaluation criteria are ◎: brightness change rate <1%; ○: 1%≦brightness change rate <2%; △: 2%≦brightness change rate <3%; ╳: brightness change rate ≧3%.

From the experimental data in Table 3, it can be seen that in the liquid crystal alignment agents of Examples 1 to 8, the first polymers used in Synthesis Examples 1 to 6 all have the structure shown in Formula (I), so that the brightness change rate of the liquid crystal display element after driving of the liquid crystal alignment agent of Examples 1 to 8 using the first polymers is 0 to ◎. It can be seen that the brightness of the liquid crystal display element formed by the liquid crystal alignment agent of the present invention using the polymer having the structure shown in Formula (I) in the dark state before driving is roughly the same as the brightness in the dark state after driving. This shows that the use of the liquid crystal alignment agent of the present invention can improve the brightness of the liquid crystal display element. After the driving is completed, it can return to the initial tilt angle. In Comparative Examples 1 to 3, the first polymer used in Comparative Synthesis Examples 1 to 3 does not have the structure shown in Formula (I), so the brightness change rate of the liquid crystal display element of the liquid crystal alignment agent after driving is X. It can be seen that the liquid crystal display element formed by the liquid crystal alignment agent without the polymer having the structure shown in Formula (I) has a large difference between the brightness in the dark state before driving and the brightness in the dark state after driving. This means that when the liquid crystal alignment agent of Comparative Examples 1 to 3 is used, the liquid crystal is not easy to return to the initial tilt angle after the driving is completed. From the above, it can be seen that the liquid crystal alignment agent of the present invention using the polymer having the structure shown in Formula (I) can indeed effectively reduce the brightness change rate of the liquid crystal display element after driving.

In summary, by using a polyimide precursor having a structure shown in formula (I) or/and an imidized polymer formed by the polyimide precursor, the liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention is used in a liquid crystal display element, and the liquid crystal can be restored to the initial tilt angle after the driving is completed, thereby giving the liquid crystal display element the advantage of a low brightness change rate after driving, so that the application requirements can be met, and the purpose of the present invention can be achieved.

However, the above is only an example of the implementation of the present invention, and it cannot be used to limit the scope of the implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the patent of the present invention.

without.

Claims (10)

A liquid crystal alignment agent for photo-alignment method comprises: a polymer component (A), including a first polymer (A1), wherein the first polymer (A1) is selected from at least one of the group consisting of a polyimide precursor and an imidized polymer formed by the polyimide precursor; and a solvent (B), wherein the polyimide precursor of the first polymer (A) comprises a structure represented by formula (I),

^X1 represents at least one of the group consisting of the structures represented by formula (I-1) to formula (I-7), wherein "*" represents a bonding position,

^X11 , ^X12 , ^X13 and ^X14 each independently represent hydrogen, a halogen, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing fluorine, or a phenyl group; ^X15 and ^X16 each independently represent hydrogen or a methyl group; ^X2 represents hydrogen or an alkyl group having 1 to 4 carbon atoms; ^X3 represents hydrogen or an alkyl group having 1 to 4 carbon atoms; ^Y1 represents

, wherein "*" represents a bonding position, R ¹ , R ² , R ³ and R ⁴ each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms, T ¹ , T ² , T ³ , T ⁴ , T ⁵ , T ⁶ , T ⁷ and T ⁸ each independently represent hydrogen or a monovalent group, m represents 1, 2 or 3, n represents 1, 2 or 3, and t represents 1, 2 or 3. The liquid crystal alignment agent for photo-alignment method as claimed in claim 1, wherein ^X1 is

,and

for

,

,

The liquid crystal alignment agent for photo-alignment method as described in claim 2, wherein ^X1 is

The liquid crystal alignment agent for photo-alignment method according to claim 1, wherein in ^Y1 , ^R1 , ^R2 , ^R3 and ^R4 represent hydrogen, and n represents 1 or 2. The liquid crystal alignment agent for photo-alignment method as described in claim 1, wherein the polyimide precursor of the first polymer (A1) is formed by reacting a reaction composition comprising a tetracarboxylic dianhydride component (a1) and a diamine component (b1), and the diamine component (b1) comprises Y ¹ in the structure represented by formula (I). The liquid crystal alignment agent for photo-alignment method as described in claim 1, wherein the polymer component (A) further comprises a second polymer (A2), and the second polymer (A2) is selected from at least one of the group consisting of polyimide precursors and imidized polymers formed by polyimide precursors, and the second polymer (A2) does not contain the structure represented by formula (I) in the first polymer (A1). The liquid crystal alignment agent for photo-alignment method as described in claim 6, wherein the polyimide precursor of the second polymer (A2) is formed by reacting a reaction composition comprising a tetracarboxylic dianhydride component (a2) and a diamine component (b2), and the tetracarboxylic dianhydride component (a2) comprises a tetracarboxylic dianhydride compound having a structure represented by formula (III),

, Z ¹¹ represents a single key, and "*" represents a key position. The liquid crystal alignment agent for photo-alignment method as described in claim 6, wherein the polyimide precursor of the second polymer (A2) is formed by reacting a reaction composition comprising a tetracarboxylic dianhydride component (a2) and a diamine component (b2), and the diamine component (b2) comprises a diamine compound having a nitrogen-containing atom structure, and the nitrogen atom structure in the diamine compound containing a nitrogen atom structure is selected from at least one of the group consisting of a heterocyclic ring containing a nitrogen atom, a diamine group and a tertiary amine group. A liquid crystal alignment film is formed by a liquid crystal alignment agent used in the photoalignment method described in any one of claims 1 to 8. A liquid crystal display element, comprising the liquid crystal alignment film described in claim 9.