TW202323506A - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display device - Google Patents

Abstract

To provide a liquid crystal alignment agent having excellent liquid crystal alignment properties. A liquid crystal alignment film having excellent liquid crystal alignment properties can be formed using a liquid crystal alignment agent containing an amic acid compound having a photoreactive structure, synthesized from raw materials containing a compound having one -NH2 and a tetracarboxylic acid derivative having a photoreactive structure. A liquid crystal display device having the liquid crystal alignment film has high contrast and prevents the occurrence of afterimage during long-term use.

Description

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

The invention relates to a liquid crystal alignment agent, a liquid crystal alignment film formed by using the liquid crystal alignment agent, and a liquid crystal display element with the liquid crystal alignment film.

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

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

In the formation of such a liquid crystal alignment film, a solution (varnish) obtained by dissolving polyamic acid, soluble polyimide, or polyamic acid ester in an organic solvent is currently mainly used. When using these varnishes to form a liquid crystal alignment film, the varnish is coated on a substrate, and then the coating film is cured by heating to form a polyimide-based liquid crystal alignment film, and if necessary, a process suitable for the display mode is performed. Alignment processing. As an alignment treatment method, there are known: a rubbing method in which the orientation of the polymer molecules is aligned by wiping the surface of the alignment film with a cloth or the like; and photoisomerization of the polymer molecules by irradiating the alignment film with linearly polarized ultraviolet rays. A photo-alignment method that imparts anisotropy to a film through photochemical changes such as dimerization or dimerization. Among them, compared with the rubbing method, the optical alignment method has higher alignment uniformity and is a non-contact alignment treatment method, so it has the advantages of not damaging the film, or reducing dust and static electricity that cause poor display of the liquid crystal display element. (Patent Document 1, etc.). Patent Document 2 provides a liquid crystal alignment film, which can introduce a photoreactive structure with a specific structure into polyamic acid or its derivatives, and impart anisotropy by a photo-alignment method, and is stable to light. [Prior art literature] [Patent Document]

[Patent Document 1] International Publication No. 2015/016118 [Patent Document 2] Japanese Patent Laid-Open No. 2020-184023

[Problem to be Solved by the Invention] The problem of the present invention is to provide a liquid crystal alignment agent with good alignment of liquid crystals, and to provide a liquid crystal display element having a liquid crystal alignment film formed of the liquid crystal alignment agent. [Technical means to solve the problem]

As described in Patent Document 1 and Patent Document 2, conventionally, the liquid crystal alignment film used in the photo-alignment method contains a polymer having a photoreactive structure, and the polymer molecules cause photochemical changes to impart various properties to the film. Anisotropy. However, the inventors of the present invention have diligently studied to solve the above problems, and found for the first time that a liquid crystal alignment film having a good alignment of liquid crystals can be obtained by using a non-polymer liquid crystal alignment agent having a photoreactive structure. The present invention has been accomplished based on these findings.

The present invention includes the following. <1> A liquid crystal alignment agent comprising an amide acid-based compound with a photoreactive structure, and in the liquid crystal alignment agent, the amide acid-based compound is composed of a compound having one -NH ₂ and a photoreactive Compounds synthesized from raw materials of tetracarboxylic acid derivatives with a neutral structure. <2> The liquid crystal alignment agent according to <1>, wherein the photoreactive structure is a structure that causes photo-Friesian rearrangement. <3> The liquid crystal alignment agent according to <1> or <2>, wherein the raw material contains a compound represented by formula (1) as the tetracarboxylic acid derivative: AXQXA (1) In the formula, A is independently Ground is a monovalent group represented by any of the following formulas. In the following formulas, n represents an integer of 1 to 4, and * represents a bonding position;

Q為以下的任一式所表示的二價基； [chemical 1]

Q is a divalent group represented by any of the following formulas;

所述二價基均可具有取代基，所述取代基選自由-CH ₃、-OCH ₃、-CF ₃及-F所組成的群組中，*表示鍵結位置； X分別獨立地為-COO-、-NHCOO-或-OCOO-。 [Chem 2]

The divalent groups can all have substituents, and the substituents are selected from the group consisting of -CH ₃ , -OCH ₃ , -CF ₃ and -F, and * indicates the bonding position; X are independently - COO-, -NHCOO-, or -OCOO-.

所述二價基均可具有取代基， 所述取代基選自由-CH ₃、-OCH ₃、-CF ₃及-F所組成的群組中， *表示鍵結位置。 <4> The liquid crystal alignment agent according to <3>, wherein in the formula (1), Q is a divalent group represented by any of the following formulas; [Chem. 3]

Each of the divalent groups can have a substituent, and the substituent is selected from the group consisting of -CH ₃ , -OCH ₃ , -CF ₃ and -F, and * indicates a bonding position.

<5> The liquid crystal alignment agent according to any one of <1> to <4>, wherein the raw material contains any of the following compounds as the tetracarboxylic acid derivative. [chemical 4]

＜7＞ 根據＜1＞至＜6＞中任一項所述的液晶配向劑，其中所述原料包含具有羥基的化合物或具有羧基的化合物的至少一種作為所述具有一個-NH ₂的化合物。 ＜8＞ 根據＜1＞至＜6＞中任一項所述的液晶配向劑，其中所述原料包含具有羥基的化合物與具有羧基的化合物作為所述具有一個-NH ₂的化合物。 ＜9＞ 根據＜1＞至＜8＞中任一項所述的液晶配向劑，還包含來自如下原料的作為反應生成物的聚合物，所述原料包含四羧酸衍生物與選自由二胺及二醯肼所組成的群組中的至少一種二胺化合物， 所述聚合物不包含光反應性結構。 ＜10＞ 根據＜1＞至＜8＞中任一項所述的液晶配向劑，實質上不含有聚合物。 ＜11＞ 一種液晶配向膜，由根據＜1＞至＜10＞中任一項所述的液晶配向劑形成。 ＜12＞ 一種液晶顯示元件，具有根據＜11＞所述的液晶配向膜。 ＜13＞ 一種液晶配向膜的製造方法，為製造液晶配向膜的方法，且具有如下步驟： 將根據＜1＞至＜10＞中任一項所述的液晶配向劑塗佈於基板上，對所形成的液晶配向劑的膜照射偏光而賦予各向異性後，進行加熱煆燒的步驟。 ＜14＞ 一種液晶顯示元件的製造方法，包括通過根據＜13＞所述的液晶配向膜的製造方法來形成液晶配向膜。 [發明的效果] <6> The liquid crystal alignment agent according to any one of <1> to <4>, wherein the raw material contains any of the following compounds as the tetracarboxylic acid derivative. [chemical 5]

<7> The liquid crystal alignment agent according to any one of <1> to <6>, wherein the raw material contains at least one of a compound having a hydroxyl group or a compound having a carboxyl group as the compound having one —NH ₂ . <8> The liquid crystal alignment agent according to any one of <1> to <6>, wherein the raw material contains a compound having a hydroxyl group and a compound having a carboxyl group as the compound having one —NH ₂ . <9> The liquid crystal alignment agent according to any one of <1> to <8>, further comprising a polymer as a reaction product derived from a raw material comprising a tetracarboxylic acid derivative and a diamine selected from and at least one diamine compound in the group consisting of dihydrazide, the polymer does not contain a photoreactive structure. <10> The liquid crystal alignment agent according to any one of <1> to <8>, which does not substantially contain a polymer. <11> A liquid crystal alignment film formed from the liquid crystal alignment agent according to any one of <1> to <10>. <12> A liquid crystal display element having the liquid crystal alignment film according to <11>. <13> A method for manufacturing a liquid crystal alignment film, comprising the following steps: coating the liquid crystal alignment agent described in any one of <1> to <10> on a substrate, and applying After the formed film of the liquid crystal alignment agent is irradiated with polarized light to impart anisotropy, a step of heating and burning is performed. <14> A method for manufacturing a liquid crystal display element, comprising forming a liquid crystal alignment film by the method for manufacturing a liquid crystal alignment film according to <13>. [Effect of the invention]

With the liquid crystal alignment agent of the present invention, a liquid crystal alignment film having good alignment properties of liquid crystals can be obtained. By using the liquid crystal alignment film, it is possible to provide a liquid crystal display element excellent in display characteristics which exhibit high contrast and are less likely to cause afterimages due to long-term use.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In addition, in this specification, the numerical range shown using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

＜＜Liquid crystal alignment agent＞＞ In this specification, a "liquid crystal alignment agent" refers to a compound or composition having a function of aligning liquid crystals. A liquid crystal alignment film may be formed using a liquid crystal alignment agent. The liquid crystal alignment agent of the present invention can be used as a liquid crystal alignment agent for photo-alignment. In this specification, a "liquid crystal aligning agent for photo-alignment" means the liquid crystal aligning agent which can impart anisotropy by irradiating polarized light when forming the film on a board|substrate.

The liquid crystal alignment agent of the present invention contains at least an amide acid-based compound with a photoreactive structure, and the amide acid-based compound is composed of a compound having one -NH ₂ and a tetracarboxylic acid derivative with a photoreactive structure. synthesis. The liquid crystal alignment agent of the present invention may also contain solvents, polymers, and other additives.

＜ Amino Acid Compounds＞ The liquid crystal alignment agent of the present invention includes an amide acid compound having a photoreactive structure. The liquid crystal alignment agent of the present invention can impart alignment by a photoalignment method by containing a compound having a photoreactive structure.

In the present specification, the term "photoreactive structure" refers to an atomic group whose structure changes when irradiated with light. Such a photoreactive structure generally has a specific site (photoreactive group) that absorbs light to cause a chemical change, and the structure changes due to the chemical change of the photoreactive group. In the following description, the chemical reaction of the photoreactive structure caused by such light absorption is referred to as "photochemical reaction", and the change of the structure due to the photochemical reaction is referred to as photochemical change. The photochemical reaction is the chemical reaction caused by electrons absorbing light and being excited, and it is distinguished from the chemical reaction caused by heating. Specific examples of photochemical changes include photodimerization, photo-Friesian rearrangement, and the like, preferably photo-Friesian rearrangement. For a specific structure, refer to the description about the photoreactive structure in the description of the tetracarboxylic acid derivative.

When forming a liquid crystal alignment film using the liquid crystal alignment agent of the present invention, for example, after the liquid crystal alignment agent is coated on a substrate to form a film, polarized light for photoalignment is irradiated. From this, it is considered that the photoreactive structure approximately parallel to the polarization direction of the light selectively causes a photochemical reaction, and the structure is changed to cause a photochemical reaction (Fries rearrangement reaction). Therefore, in the photoreactive structure approximately parallel to the polarization direction of the light in the molecules randomly aligned by light irradiation, a photochemical reaction (photo-Friesian rearrangement reaction) is caused, and as a result, approximately at right angles to the polarization direction The alignment components of the molecules occupy a dominant position and become a highly aligned state in a specific direction. Thereafter, a solid liquid crystal alignment film is formed by heating and burning the photo-aligned film. Conventionally, polymers having a photoreactive structure have been used for such alignment, but the present inventors have found that photoalignment can be performed using a non-polymer compound having a photoreactive structure.

The amide acid-based compound having a photoreactive structure contained in the liquid crystal alignment agent of the present invention is a non-polymer compound, and its molecular weight is preferably 3000 or less, more preferably 2000 or less, and still more preferably 1500 or less.

The amide acid-based compound having a photoreactive structure is a compound synthesized from raw materials including a tetracarboxylic acid derivative having a photoreactive structure and a compound having one -NH ₂ .

As long as the amide acid-based compound is a synthetic compound comprising the following steps: the two carboxyl groups of tetracarboxylic acid corresponding to tetracarboxylic dianhydride, tetracarboxylic diester and tetracarboxylic diester dihalide are respectively combined with The -NH ₂ reaction of a -NH ₂ compound causes two water molecules to detach from the step. Therefore, the amide acid-based compound is a compound obtained by reacting 2 molecules of a compound having one -NH ₂ with 1 molecule of a tetracarboxylic acid derivative.

Typically, the amide acid-based compound is amide acid (bisamide acid) having two amide acid groups. In addition, the amide acid-based compound may be an amide acid derivative. For example, it may be an amidoester or amidoamide derived from amido acid.

Hereinafter, the amide acid-based compound will be described in detail. Amino acid, which is one of the amide acid-based compounds, is the chemical reaction of a compound having one -NH ₂ represented by the formula (MA) and a tetracarboxylic acid derivative represented by the formula (PAN) as shown in the following reaction formula. A compound synthesized by reaction, and represented by formula (AA). When the liquid crystal alignment agent containing amide acid is heated and baked in the step of forming the liquid crystal alignment film, the amide acid is imidized to form a liquid crystal alignment film represented by formula (IA).

（式中，X ²表示一價有機基；X ¹表示四價有機基） [chemical 6]

(In the formula, X ² represents a monovalent organic group; X ¹ represents a tetravalent organic group)

Amino acid in the present invention can be obtained, for example, by stirring formula (MA) and formula (PAN) in an aprotic polar organic solvent, and heating if necessary. When heating, it is preferably 40°C to 80°C, more preferably 50°C to 80°C, and still more preferably 60°C to 80°C.

For the preferred range and specific examples of the tetravalent organic group in ^X1 , refer to the structures corresponding to the tetracarboxylic acid derivatives described in the following tetracarboxylic acid derivatives. For the preferred range and specific examples of the monovalent organic group in X ² , refer to the descriptions related to the structure corresponding to the compound having one -NH ₂ in the column of compounds having one -NH ₂ below.

Furthermore, for example, amide esters can be synthesized by reacting the amide acid with a compound containing a hydroxyl group, a halide, a compound containing an epoxy group, or the like; or by making a tetracarboxylic acid derived from an acid dianhydride A diester or tetracarboxylic acid diester halide is reacted with a monoamine compound. In addition, the amido ester may have only the amido ester structure, or may be a partial esterified product in which the amido acid structure and the amido ester structure coexist.

The amide acid-based compound having a photoreactive structure contained in the liquid crystal alignment agent of the present invention may be one (one type), or two (two or more types). The amino acid-based compound most contained in the liquid crystal alignment agent of the present invention is preferably bis-amido acid. The bisamido acid having a photoreactive structure contained in the liquid crystal alignment agent of the present invention may be one (one type), or two (two or more types).

For example, by using two or more tetracarboxylic acid derivatives represented by the formula (PAN) to synthesize an amide acid-based compound as described above, two or more amide acid-based compounds having a photoreactive structure can be produced. liquid crystal aligning agent. In addition, by using two or more compounds represented by the formula (MA) having one -NH ₂ to synthesize an amide acid-based compound as described above, two or more compounds containing two or more (after making two or more compounds having one - In the case of simultaneous reaction of NH ₂ compounds, it is a liquid crystal alignment agent of an amide acid-based compound having a photoreactive structure. In addition, two or more amide acid-based compounds synthesized separately may be mixed to manufacture a liquid crystal alignment agent including two or more amide acid-based compounds having a photoreactive structure.

The content of the amide acid-based compound having a photoreactive structure in the liquid crystal alignment agent of the present invention is preferably 20% by mass to 100% by mass relative to the total mass of the solid content of the liquid crystal alignment agent (mass excluding the mass of the solvent), More preferably, it is 30 mass % - 100 mass %.

The liquid crystal alignment agent of the present invention may further contain an amide acid compound not having a photoreactive structure in addition to the amide acid compound having a photoreactive structure. The molar amount of the amide acid-based compound having a photoreactive structure relative to the total molar amount of the amide-based compound in the liquid crystal alignment agent of the present invention is preferably 30 mole % or more, more preferably 50 mole % or more , more preferably 70 mol% or more, particularly preferably 90 mol% or more.

Amino acid-based compounds and amide-based compounds with a photoreactive structure can be confirmed by the following methods: using infrared spectroscopy (Infrared spectroscopy, IR), nuclear magnetic resonance analysis (Nuclear Magnetic Resonance, NMR) The solid content obtained by precipitating amide acid-based compounds and amide acid-based compounds with photoreactive structures in a large amount of poor solvent is analyzed.

＜Tetracarboxylic acid derivatives＞ As one of the raw materials of the amide acid-based compound, at least one tetracarboxylic acid derivative can be used. The term "tetracarboxylic acid derivative" means at least one selected from the group consisting of tetracarboxylic dianhydride, tetracarboxylic diester, and tetracarboxylic diester dihalide. As tetracarboxylic acid derivatives, generally speaking, as long as tetracarboxylic dianhydrides are used, as long as tetracarboxylic acid diesters or tetracarboxylic acid diester dihalides are used according to the needs of producing amide acid-based compounds. Can. Tetracarboxylic acid diesters derived from tetracarboxylic dianhydrides can be obtained, for example, by reacting tetracarboxylic dianhydrides with 2 equivalents of alcohol and opening rings, and tetracarboxylic acid diester dihalides can be obtained by making tetracarboxylic acid diesters It is obtained by reacting with 2 equivalents of a halogenating agent (for example, thionyl chloride, etc.).

As the tetracarboxylic acid derivative used in the synthesis of the amide acid-based compound having a photoreactive structure, at least one tetracarboxylic acid derivative having a photoreactive structure can be used. For example, as the tetracarboxylic acid derivative having a photoreactive structure, one (one) compound may be used, or two (two) or more compounds may be used.

When the liquid crystal alignment agent of the present invention further includes an amide acid-based compound that does not have a photoreactive structure, the amide acid-based compound only needs to be synthesized from a raw material that contains a tetracarboxylic acid derivative that does not have a photoreactive structure. . The amide acid compound having a photoreactive structure and the amide acid compound not having a photoreactive structure may be synthesized simultaneously, or may be synthesized independently and mixed.

The photoreaction related to the photoreactive structure of the tetracarboxylic acid derivative used in the present invention includes at least one chemical reaction selected from the group consisting of photodimerization and photofries rearrangement. The wavelength of light for causing structural changes in the photoreactive structure is not particularly limited, but is preferably 150 nm to 800 nm, more preferably 200 nm to 400 nm, and still more preferably 200 nm to 300 nm. In addition, the light irradiation intensity required to cause a structural change in the photoreactive structure is preferably 0.05 J/cm ² to 10 J/cm ² .

The photoreactive structure contained in the tetracarboxylic acid derivative used in the present invention is preferably a structure that causes photo-Friesian rearrangement. Examples of structures that cause photo-Friesian rearrangement include: a structure in which an ester bond is bonded to an aromatic ring through an oxygen atom in the bond, and a structure in which a urethane bond is bonded to an aromatic ring through a nitrogen atom in this bond. structure on the ring. Here, as the aromatic ring, in addition to the benzene ring, condensed rings (naphthalene, anthracene, etc.) including the benzene ring can also be mentioned.

The tetracarboxylic acid derivative having a photoreactive structure is preferably a compound having two acid anhydride groups at the terminal and containing at least a photoreactive structure therebetween. Examples of the acid anhydride group include a group including a succinic anhydride structure, and a group including a succinic anhydride structure and a ring-condensed structure (for example, a succinic anhydride structure).

As an example of the tetracarboxylic-acid derivative which has a photoreactive structure, the compound represented by following formula (1) is mentioned. A-X-Q-X-A (1)

In formula (1), A is each independently a monovalent group represented by any of the following formulas. [chemical 7]

In the formula, n1 represents an integer of 1 to 4, and * represents a bonding position. In the above formula, when the other end of the bonding bond at one end represented by * as the bonding position is located inside the ring, the other end may be replaced by a hydrogen atom on the ring. The terminus bonded to any carbon atom capable of bonding.

A is preferably a monovalent group represented by the following formula, and the bonding position is preferably a para-position of the bonding position of any -(C=O)-. [chemical 8]

In formula (1), Q is a divalent group represented by any of the following formulas. [chemical 9]

In the formula, * represents a bonding position. In the above formula, when the other end of the bonding bond at one end represented by * as the bonding position is located inside the ring, the other end may be replaced by a hydrogen atom on the ring. The terminus bonded to any carbon atom capable of bonding.

For example, examples of the bonding positions of the divalent groups represented by the above formulas include the following. [chemical 10]

Each of the divalent groups exemplified as Q may have a substituent selected from the group consisting of -CH ₃ , -OCH ₃ , -CF ₃ , and -F.

Q is preferably 1,4-phenylene, 4,4'-biphenylene, or 2,6-naphthylene. More preferably, none of them are substituted.

X are each independently -COO-, -NHCOO- or -OCOO-. These may be bonded to A via any bonding bond, respectively. X is preferably all -COO-, and -COO- is preferably bonded to A at C and bonded to Q at O. As a more specific example of the tetracarboxylic-acid derivative which has a photoreactive structure, the compound represented by any one of the following formulas is mentioned.

[chemical 11]

When the liquid crystal alignment agent of the present invention contains an amide acid-based compound that does not have a photoreactive structure, the tetracarboxylic acid derivative that does not have a photoreactive structure used in its synthesis is not particularly limited, and can be freely selected from Select from known tetracarboxylic acid derivatives (especially tetracarboxylic dianhydride). As an example of a specific compound, the example of the tetracarboxylic-acid derivative used for manufacture of the polyamic acid mentioned later can be referred.

<Compound having one -NH ₂ > As a raw material of an amide acid-based compound, a compound having one -NH ₂ is used in addition to a tetracarboxylic acid derivative. In this specification, a compound having one -NH ₂ is a compound having only one group selected from the group consisting of a primary amine group and hydrazine in its structure. The compound having one -NH ₂ can be selected from known compounds without limitation. As the compound having one -NH ₂ used in the production of the liquid crystal alignment agent of the present invention, one (one) compound may be used, and two (two) or more compounds may be used. Regarding the compound having one _-NH used in the synthesis of amide acid-based compounds, the total amount is preferably 180 mol% to 220 mol%, more preferably 190 mol, relative to the total amount of tetracarboxylic acid derivatives. mol% to 210 mol%, more preferably 200 mol%.

When two or more compounds are used as the compound having one -NH ₂ and reacted simultaneously, even when one tetracarboxylic acid derivative is used, three or more amide acid-based compounds can be produced. The liquid crystal alignment agent of the present invention may also be a mixture thereof. In addition, if necessary, one type of amide acid-based compound can be isolated and used.

Examples of compounds having one —NH ₂ include compounds represented by the following formulas (2-1) to (2-4).

[chemical 12]

In formula (2-1), R ¹ represents -H, -OH, -COOH, -F or an alkoxy group having 1 to 4 carbon atoms, and m1 is an integer of 1 to 8. In Formula (2-2) - Formula (2-4), n is each independently an integer of 0-5, and m2 is each independently an integer of 0-8. In formula (2-4), m3 is an integer of 0-4. In formula (2-2) and formula (2-4), ^R2 each independently represents -OH, -COOH, -F, alkyl with 1 to 4 carbons, alkoxy with 1 to 4 carbons, or carbon A hydroxyalkyl group with a number of 1 to 4. When n is 2 or more, a plurality of R ² may be the same or different. In the formula (2-3), R ³ each independently represent -OH, -COOH, -F, alkyl with 1 to 4 carbons, alkoxy with 1 to 4 carbons, hydroxyalkane with 1 to 4 carbons morpholinyl, oxazolyl or piperazinyl. When n is 2 or more, a plurality of R ³ may be the same or different. In formula (2-1) to formula (2-4), at least one -CH ₂ - may be substituted by -C(=O)NH-, -O-, -NH-, but O will not be adjacent.

The alkyl group having 1 to 4 carbon atoms in the "alkyl group having 1 to 4 carbon atoms" and the "alkoxy group having 1 to 4 carbon atoms" is preferably a linear alkyl group. In addition, the alkylene group having 1 to 4 carbons in the "hydroxyalkyl group having 1 to 4 carbons" is preferably a linear alkylene group.

In formula (2-1), R ¹ is preferably -OH or -COOH. m1 is preferably 3-8, more preferably 5-8. It is also preferred that at least one _-CH2- is substituted by -O- or -NH-.

In formula (2-2) and formula (2-4), n is preferably 1 or 2. In each formula, at least one R ² is preferably -OH, -COOH, hydroxyalkyl having 1 to 4 carbons, or alkoxy having 1 to 4 carbons. In formula (2-3), n is preferably 1 or 2. At least one ^R3 is preferably -OH, -COOH, hydroxyalkyl having 1 to 4 carbons, alkoxy having 1 to 4 carbons, morpholinyl, oxazolyl or piperazinyl. In Formula (2-2) to Formula (2-4), m2 is each independently preferably 0-3, more preferably 0. In formula (2-4), m3 is preferably 1-3, more preferably 1 or 2. It is also preferred that m3 is 1 and one _-CH2- is replaced by -C(=O)NH-, -O- or -NH-.

Specific examples of the compound represented by the formula (2-1) having one —NH ₂ include compounds represented by the following formulas (2-1-1) to (2-1-4).

[chemical 13]

Specific examples of the compound represented by the formula (2-2) having one —NH ₂ include compounds represented by the following formulas (2-2-1) to (2-2-2).

[chemical 14]

Specific examples of the compound having one —NH ₂ represented by the formula (2-3) include compounds represented by the following formulas (2-3-1) to (2-3-10).

作為式（2-4）所表示的具有一個-NH ₂的化合物的具體例，可列舉下述式（2-4-1）～式（2-4-2）所表示的化合物。 [chemical 15]

Specific examples of the compound represented by the formula (2-4) having one —NH ₂ include compounds represented by the following formulas (2-4-1) to (2-4-2).

[chemical 16]

As the compound having one -NH ₂ , it is preferable to use at least one of a compound having a hydroxyl group or a compound having a carboxyl group. As the compound having one -NH ₂ , a compound having a hydroxyl group and a compound having a carboxyl group can be used together. That is, a compound having at least one group containing a hydroxyl group (-OH or a hydroxyalkyl group having 1 to 4 carbon atoms) as R ¹ , R ² or R ³ and a compound having at least one carboxyl group as R ¹ , R ² or R ³ can be used. compound of. For example, a compound represented by formula (2-3-2), which is a compound having a carboxyl group, is preferably used in combination with a compound having one —NH ₂ and a hydroxyl group. A compound having a hydroxyl group and a compound having a carboxyl group may be used in combination when synthesizing an amide acid-based compound, or a compound having a hydroxyl group and a compound having a carboxyl group may be used separately when synthesizing other amide acid-based compounds.

By using a compound having a hydroxyl group and a compound having a carboxyl group as a compound having one -NH ₂ when synthesizing an amide acid-based compound, it is possible to produce a compound containing a hydroxy group, a compound having a carboxyl group, and a compound having both as an amide acid A liquid crystal alignment agent based on a compound. In addition, an amide acid-based compound synthesized using a compound having a hydroxyl group as a compound having one -NH ₂ and an amide acid-based compound synthesized using a compound having a carboxyl group as a compound having one -NH ₂ can be mixed , to obtain a liquid crystal alignment agent comprising a compound having a hydroxyl group and a compound having a carboxyl group as an amide acid compound. Regarding any of the above-mentioned liquid crystal alignment agents, in the heating and kneading step for forming the liquid crystal alignment film described later, the hydroxyl and carboxyl groups react to be esterified and polymerized, which can contribute to the production of an anisotropic film immobilization. In the case of using a compound having a hydroxyl group and one -NH ₂ and a compound having a carboxyl group and one -NH ₂ , the molar ratio of the two is typically about 1:1, for example, It can adjust in the range of 1:9-9:1 according to the presence or absence, quantity, etc. of other components, such as a polymer, in a liquid crystal aligning agent.

<Polymer> Conventionally, liquid crystal alignment agents have been known to contain polymer compositions, but the liquid crystal alignment agent of the present invention can form liquid crystals with good liquid crystal alignment even if they contain only amide acid-based compounds without polymers. Alignment film. In particular, by using a compound having a hydroxyl group and a compound having a carboxyl group as the compound having one -NH ₂ , in the heating and kneading step for forming a liquid crystal alignment film, the hydroxyl and carboxyl groups react to esterify and polymerize Therefore, even in a composition that does not contain a polymer, a highly stable liquid crystal alignment film can be formed.

On the other hand, the liquid crystal alignment agent of the present invention may further include a polymer in addition to the amide acid-based compound. The balance of the storage stability of a liquid crystal alignment agent, the printability of a liquid crystal alignment agent to a display element board|substrate, and the characteristic of the formed liquid crystal alignment film can be adjusted by setting it as the structure containing a polymer as needed.

The molecular weight of the amide acid-based compound and the polymer is different, and the amide acid-based compound with a smaller molecular weight can be segregated in the upper layer. That is, in the process of coating a liquid crystal alignment agent containing an amide acid-based compound and a polymer in a solvent on a substrate as described later, and pre-drying to form a thin film, the amide acid-based compound can be segregated in The upper layer of the film, causing the polymer to segregate to the lower layer of the film. Confirmation of layer separation can be confirmed by confirming that the surface energy of the formed alignment film is the same or close to the surface energy of an alignment film formed of a liquid crystal alignment agent containing only an amide-based compound.

When the liquid crystal alignment agent of the present invention contains a polymer, the type of polymer contained in the liquid crystal alignment agent may be one type, or two or more types. The polymer contained in the liquid crystal alignment agent of the present invention preferably does not contain a photoreactive structure.

When the liquid crystal alignment agent of the present invention contains a polymer, the content of the polymer in the liquid crystal alignment agent is preferably 10% by mass to 80% by mass relative to the total solid mass of the liquid crystal alignment agent (mass excluding the solvent mass). %, more preferably 10% by mass to 70% by mass.

The polymer contained in the liquid crystal alignment agent of the present invention is not particularly limited, but is preferably polyamic acid or its derivatives.

Polyamic acid is at least one tetracarboxylic acid derivative selected from the group consisting of tetracarboxylic dianhydride, tetracarboxylic diester and tetracarboxylic diester dihalide, and selected from the group consisting of diamine and diamine A polymer synthesized by the polymerization reaction of at least one diamine compound in the group consisting of hydrazine. For example, polyamic acid is a polymer synthesized by the polymerization reaction of diamine represented by formula (DI) and tetracarboxylic acid derivative represented by formula (AN), and has a structural unit represented by formula (PAA) . By imidizing polyamide acid, a polyimide liquid crystal alignment film having a structural unit represented by formula (PI) can be formed.

[chemical 17]

In formula (AN), formula (PAA) and formula (PI), X ³ represents a tetravalent organic group. In formula (DI), formula (PAA) and formula (PI), X ⁴ represents a divalent organic group.

The derivative of polyamic acid is a compound whose characteristics are changed by substituting a part of polyamic acid with other atoms or atomic groups, and is particularly preferably a compound having improved solubility in a solvent used in a liquid crystal alignment agent. Derivatives of polyamic acid may include: 1) Polyimide formed by dehydration and ring-closure reaction of all amine groups and carboxyl groups of polyamide acid, 2) Partial polyimide formed by partial dehydration and ring-closure reaction , 3) Polyamic acid ester obtained by converting the carboxyl group of polyamic acid into an ester, 4) Polyamic acid-polyacid obtained by substituting a part of tetracarboxylic acid derivative with organic dicarboxylic acid and reacting An amide copolymer, and 5) a polyamideimide obtained by subjecting part or all of the polyamide acid-polyamide copolymer to a dehydration ring-closure reaction.

As a tetracarboxylic acid derivative used in the production of polyamic acid or its derivatives, tetracarboxylic dianhydrides that do not have a photoreactive structure, or the corresponding tetracarboxylic acid diesters or tetracarboxylic acid derivatives can be used. Acid diester dihalides. As suitable examples of tetracarboxylic acid derivatives that do not have a photoreactive structure, formula (AN-I) ~ Tetracarboxylic acid derivatives represented by formula (AN-VII).

[chemical 18]

In formula (AN-I), formula (AN-IV) and formula (AN-V), X is independently a single bond or -CH ₂ -. In formula (AN-II), G is a single bond, an alkylene group with 1 to 20 carbons, -CO-, -O-, -S-, -SO ₂ -, -C(CH ₃ ) ₂ - or - C(CF ₃ ) ₂ -. In formula (AN-II) ~ formula (AN-IV), Y is independently selected from the group of the following trivalent groups (* represents the bonding position), and the bonding bond is connected to any carbon, and the At least one hydrogen of the radical may be substituted by methyl, ethyl or phenyl.

[chemical 19]

In formula (AN-III) to formula (AN-V), ring A ¹⁰ is a monocyclic hydrocarbon group with 3 to 10 carbons or a condensed polycyclic hydrocarbon group with 6 to 30 carbons, and the group At least one hydrogen may be substituted by a methyl group, an ethyl group or a phenyl group, and the bonding bond connected to the ring is connected to any carbon constituting the ring, and two bonding bonds may be connected to the same carbon. In the formula (AN-VI), X ¹⁰ is an alkylene group having 2 to 6 carbon atoms, Me represents a methyl group, and Ph represents a phenyl group. In formula (AN-VII), r is 0 or 1 independently.

More specifically, tetracarboxylic acid derivatives represented by the following formula (AN-1) and formula (AN-3) to formula (AN-16-15) are mentioned.

[Tetracarboxylic acid derivative represented by formula (AN-1)] [Chem. 20]

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

[chem 21]

When G ¹² is >CH-, the hydrogen of >CH- may be replaced by -CH ₃ . When G ¹² is >N-, G ¹¹ is not a single bond and -CH ₂ -, and X ¹¹ is not a single bond. Also, R ¹¹ is independently hydrogen or -CH ₃ .

式（AN-1-2）及式（AN-1-14）中，m為1～12的整數。 As an example of the tetracarboxylic-acid derivative represented by Formula (AN-1), the compound represented by the following formula is mentioned. [chem 22]

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

式（AN-3）中，環A ¹¹為環己烷環或苯環。 [Tetracarboxylic acid derivative represented by formula (AN-3)] [Chem. 23]

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

As an example of the tetracarboxylic-acid derivative represented by Formula (AN-3), the compound represented by the following formula is mentioned. [chem 24]

[Tetracarboxylic acid derivative represented by formula (AN-4)] [Chem. 25]

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

[chem 26]

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

As an example of the tetracarboxylic-acid derivative represented by Formula (AN-4), the compound represented by the following formula is mentioned.

[chem 27]

式（AN-4-17）中，m為1～12的整數。 [chem 28]

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

[chem 29]

[chem 30]

式（AN-5）中，R ¹¹為氫或-CH ₃。鍵結位置未固定於構成苯環的碳原子上的R ¹¹表示在苯環上的鍵結位置為任意。 [Tetracarboxylic acid derivative represented by formula (AN-5)] [Chem. 31]

In formula (AN-5), R ¹¹ is hydrogen or -CH ₃ . R ¹¹ whose bonding position is not fixed to the carbon atom constituting the benzene ring means that the bonding position on the benzene ring is arbitrary.

As an example of the tetracarboxylic-acid derivative represented by Formula (AN-5), the compound represented by the following formula is mentioned. [chem 32]

式（AN-6）中，X ¹¹獨立地為單鍵或-CH ₂-。X ¹²為-CH ₂-、-CH ₂CH ₂-或-CH=CH-。n為1或2。 [Tetracarboxylic acid derivative represented by formula (AN-6)] [Chem. 33]

In formula (AN-6), X ¹¹ is independently a single bond or -CH ₂ -. X ¹² is -CH ₂ -, -CH ₂ CH ₂ - or -CH=CH-. n is 1 or 2.

Examples of the tetracarboxylic acid derivative represented by the formula (AN-6) include compounds represented by the following formula. [chem 34]

式（AN-7）中，X ¹¹為單鍵或-CH ₂-。 [Tetracarboxylic acid derivative represented by formula (AN-7)] [Chem. 35]

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

As an example of the tetracarboxylic-acid derivative represented by Formula (AN-7), the compound represented by the following formula is mentioned. [chem 36]

式（AN-8）中，X ¹¹為單鍵或-CH ₂-。R ¹²為氫、-CH ₃、-CH ₂CH ₃或苯基，環A ¹²為環己烷環或環己烯環。 [Tetracarboxylic acid derivative represented by formula (AN-8)] [Chemical 37]

In formula (AN-8), X ¹¹ is a single bond or -CH ₂ -. R ¹² is hydrogen, -CH ₃ , -CH ₂ CH ₃ or phenyl, and ring A ¹² is a cyclohexane ring or a cyclohexene ring.

As an example of the tetracarboxylic-acid derivative represented by Formula (AN-8), the compound represented by the following formula is mentioned. [chem 38]

式（AN-9）中，r分別獨立地為0或1。 [Tetracarboxylic acid derivative represented by formula (AN-9)] [Chemical 39]

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

As an example of the tetracarboxylic-acid derivative represented by Formula (AN-9), the compound represented by the following formula is mentioned. [chemical 40]

[Tetracarboxylic acid derivatives represented by formula (AN-10-1) and formula (AN-10-2)] [Chem. 41]

式（AN-11）中，環A ¹¹獨立地為環己烷環或苯環。 [Tetracarboxylic acid derivative represented by formula (AN-11)] [Chem. 42]

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

As an example of the tetracarboxylic-acid derivative represented by Formula (AN-11), the compound represented by the following formula is mentioned. [chem 43]

式（AN-12）中，環A ¹¹分別獨立地為環己烷環或苯環。 [Tetracarboxylic acid derivative represented by formula (AN-12)] [Chem. 44]

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

As an example of the tetracarboxylic-acid derivative represented by Formula (AN-12), the compound represented by the following formula is mentioned. [chem 45]

式（AN-13）中，X ¹³為碳數2～6的伸烷基，Ph表示苯基。 [Tetracarboxylic acid derivative represented by formula (AN-13)] [Chem. 46]

In the formula (AN-13), X ¹³ is an alkylene group having 2 to 6 carbon atoms, and Ph represents a phenyl group.

Examples of the tetracarboxylic acid derivative represented by the formula (AN-13) include compounds represented by the following formula. [chem 47]

式（AN-14）中，r獨立地為0或1。 [Tetracarboxylic acid derivative represented by formula (AN-14)] [Chem. 48]

In formula (AN-14), r is 0 or 1 independently.

Examples of the tetracarboxylic acid derivative represented by the formula (AN-14) include compounds represented by the following formula. [chem 49]

式（AN-15）中，w為1～10的整數。 [Tetracarboxylic acid derivative represented by formula (AN-15)] [Chem. 50]

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

Examples of the tetracarboxylic acid derivative represented by the formula (AN-15) include compounds represented by the following formula. [Chemical 51]

As tetracarboxylic acid derivatives other than those mentioned above, the following compounds are mentioned. [Chemical 52]

Among the tetracarboxylic acid derivatives having no photoreactive structure, suitable materials for improving various properties will be described.

When emphasis is placed on improving the alignment of liquid crystals, compounds represented by formula (AN-1), formula (AN-3) and formula (AN-4) are preferred, and compounds represented by formula (AN-1-2), Compounds represented by formula (AN-1-13), formula (AN-3-2), formula (AN-4-5), formula (AN-4-17) and formula (AN-4-29). In formula (AN-1-2), m=4 or 8 is preferable. In the formula (AN-4-17), m=4 or 8 is preferable, and m=8 is more preferable.

In the case of emphasizing the improvement of the transmittance of the liquid crystal display element, among the tetracarboxylic acid derivatives, the formula (AN-1-1), the formula (AN-1-2), and the formula (AN-3-1) are preferred. , formula (AN-4-17), formula (AN-4-30), formula (AN-5-1), formula (AN-7-2), formula (AN-10-1), formula (AN- 16-3) and the compound represented by formula (AN-16-4). In formula (AN-1-2), m=4 or 8 is preferable. In the formula (AN-4-17), m=4 or 8 is preferable, and m=8 is more preferable.

When emphasis is placed on improving the voltage holding ratio (Voltage Holding Ratio, VHR) of the liquid crystal display element, among the tetracarboxylic acid derivatives, the formula (AN-1-1), formula (AN-1-2), Formula (AN-3-1), Formula (AN-4-17), Formula (AN-4-30), Formula (AN-7-2), Formula (AN-10-1), Formula (AN-16 -1), the compound represented by formula (AN-16-3) and formula (AN-16-4), in formula (AN-1-2), m=4 or 8 is preferable. In the formula (AN-4-17), m=4 or 8 is preferable, and m=8 is more preferable.

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

The diamine compound selected from diamines and dihydrazides used in the production of polyamide acids and derivatives thereof can be selected from known diamines and dihydrazides without limitation. Regarding the diamine compound, one compound may be reacted with a tetracarboxylic acid derivative, or two or more compounds may be mixed and reacted with a tetracarboxylic acid derivative. In this specification, a "diamine compound" means not only one kind of compound, but the mixture of two or more kinds of compounds may also be included in the meaning. In addition, in this specification, dihydrazide is also handled as a "diamine compound".

The diamine compound preferably does not have a photoreactive structure.

Diamine compounds that do not have a photoreactive structure can be classified into two types according to their structures. That is, a diamine compound having a side chain group branched from the main chain when the skeleton connecting two amine groups is regarded as the main chain, and a diamine compound not having a side chain group. The side chain group is a group having an effect of increasing the pretilt angle. The side chain group having this effect must be a group with 3 or more carbon atoms. As specific examples, it can be cited: an alkyl group with 3 or more carbon atoms, an alkoxy group with 3 or more carbon atoms, and an alkoxy group with 3 or more carbon atoms. An alkyl group and a group having a steroid skeleton. As a group having one or more rings, the terminal ring has any one of an alkyl group having 1 or more carbon atoms, an alkoxy group having 1 or more carbon atoms, and an alkoxyalkyl group having 2 or more carbon atoms as a substituent. It has the effect of being a side chain group. In the following description, the diamine compound which has such a side chain group may be called a side chain type diamine compound. Moreover, the diamine compound which does not have such a side chain group may be called a non-side chain type diamine compound.

By appropriately using a non-side chain type diamine compound and a side chain type diamine compound separately, it is possible to respond to each desired pretilt angle. It is preferable to use side chain type diamine compound in combination to such an extent that the characteristics of this invention are not impaired. In addition, the side chain type diamine compound and the non-side chain type diamine compound are preferably selected for the purpose of improving the vertical alignment property with respect to the liquid crystal, the voltage retention rate, the burn mark characteristic, and the alignment property.

The non-side chain type diamine compound will be described. As a known diamine compound which does not have a side chain, the diamine compound of following formula (DI-1) - a formula (DI-16) is mentioned. [Chemical 53]

In the formula (DI-1), G ²⁰ is -CH ₂ -, at least one -CH ₂ - may be substituted by -NH-, -O-, m is an integer from 1 to 12, at least one hydrogen of the alkylene group is Can be substituted by -OH. In formula (DI-3) and formula (DI-5) to formula (DI-7), G ²¹ is independently a single bond, -NH-, -NCH ₃ -, -O-, -S-, -SS- , -SO ₂ -, -CO-, -CONCH ₃ -, -CONH-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -(CH ₂ ) _m -, -O-(CH ₂ ) _m -O-, -N(CH ₃ )-(CH ₂ ) _k -N(CH ₃ )-, -(OC ₂ H ₄ ) _m -O-, -O-CH ₂ -C(CF ₃ ) ₂ -CH ₂ -O-, -(CH ₂ ) _m -NH-(CH ₂ ) _m -, -CO-(CH ₂ ) _k -NH-(CH ₂ ) _k -, -(NH-(CH ₂ ) _m ) _k -NH-, -CO-C ₃ H ₆ -(NH-C ₃ H ₆ ) _n -CO- or -S-(CH ₂ ) _m -S-, m is independently an integer of 1 to 12, k is an integer of 1-5, and n is 1 or 2. In formula (DI-4), s is an integer of 0-2 independently. In formula (DI-6) and formula (DI-7), G ²² is independently a single bond, -O-, -S-, -CO-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -NH- or an alkylene group having 1 to 10 carbon atoms. At least one hydrogen of the cyclohexane ring and benzene ring in formula (DI-2) ~ formula (DI-7) can be passed through -F, -Cl, alkylene with 1 to 3 carbons, -OCH ₃ , -OH , -CF ₃ , -CO ₂ H, -CONH ₂ , -NHC ₆ H ₅ , phenyl or benzyl substitution, in addition, in formula (DI-4), at least one hydrogen of cyclohexane ring and benzene ring It may be substituted by one selected from the group represented by the following formula (DI-4-a) - a formula (DI-4-e). The group whose bonding position is not fixed to the carbon atom constituting the ring means that the bonding position on the ring is arbitrary. Also, the bonding position of -NH ₂ on the cyclohexane ring or the benzene ring is any position other than the bonding position of G ²¹ or G ²² .

式（DI-4-a）及式（DI-4-b）中，R ²⁰獨立地為氫或-CH ₃。 [Chemical 54]

In formula (DI-4-a) and formula (DI-4-b), R ²⁰ is independently hydrogen or -CH ₃ .

式（DI-11）中，r為0或1。式（DI-8）～式（DI-11）中，鍵結於環上的-NH ₂的鍵結位置為任意位置。 [Chemical 55]

In formula (DI-11), r is 0 or 1. In the formula (DI-8) to the formula (DI-11), the bonding position of -NH ₂ bonded to the ring is an arbitrary position.

[Chemical 56]

In formula (DI-12), R ²¹ and R ²² are independently alkyl or phenyl with 1 to 3 carbons, and G ²³ is independently alkylene, phenylene or alkylene with 1 to 6 carbons. Substituted phenylene group, w is an integer of 1-10. In formula (DI-13), ^R23 is independently an alkyl group with 1 to 5 carbons, an alkoxy group with 1 to 5 carbons, or -Cl, p is independently an integer of 0 to 3, and q is 0 to 4 an integer of . In formula (DI-14), ring B is a monocyclic heteroaromatic, R ²⁴ is hydrogen, -F, -Cl, alkyl, alkoxy, vinyl, or alkynyl with 1 to 6 carbons, and q is independent ground is an integer of 0-4. In formula (DI-15), ring C is a monocyclic ring containing a heteroatom. In the formula (DI-16), G ²⁴ is a single bond, an alkylene group having 2 to 6 carbon atoms or a 1,4-phenylene group, and r is 0 or 1. Furthermore, a group whose bonding position is not fixed to a carbon atom constituting the ring means that the bonding position on the ring is arbitrary. In the formula (DI-13) to the formula (DI-16), the bonding position of -NH ₂ bonded to the ring is an arbitrary position.

Specific examples of the following formulas (DI-1-1) to (DI-16-1) as the diamine compounds having no side chains of the above-mentioned formulas (DI-1) to (DI-16) .

式（DI-1-7）及式（DI-1-8）中，k分別獨立地為1～3的整數。 Examples of diamine compounds represented by formula (DI-1) are shown below. [Chemical 57]

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

Examples of diamine compounds represented by formula (DI-2) and formula (DI-3) are shown below. [Chemical 58]

[化60]

[化61]

[化62]

Examples of diamine compounds represented by formula (DI-4) are shown below. [Chemical 59]

[Chemical 60]

[Chemical 61]

[chem 62]

式（DI-5-1）中，m為1～12的整數。 [化64]

式（DI-5-12）及式（DI-5-13）中，m為1～12的整數。 [化65]

式（DI-5-16）中，v為1～6的整數。 [化66]

式（DI-5-30）中，k為1～5的整數。 [化67]

Examples of diamine compounds represented by formula (DI-5) are shown below. [chem 63]

In formula (DI-5-1), m is an integer of 1-12. [chem 64]

In formula (DI-5-12) and formula (DI-5-13), m is an integer of 1-12. [chem 65]

In formula (DI-5-16), v is an integer of 1-6. [chem 66]

In formula (DI-5-30), k is an integer of 1-5. [chem 67]

In formula (DI-5-36) ~ formula (DI-5-37) and formula (DI-5-39), m is an integer from 1 to 12, formula (DI-5-38) and formula (DI-5 -39), k is an integer of 1 to 5, and in formula (DI-5-40), n is an integer of 1 or 2.

Examples of diamine compounds represented by formula (DI-6) are shown below. [chem 68]

Examples of diamine compounds represented by formula (DI-7) are shown below. [chem 69]

In formula (DI-7-3) - formula (DI-7-4), m is an integer of 1-12, and in formula (DI-7-3), n is 1 or 2 independently. [chem 70]

式（DI-7-12）中，m為1～12的整數。 [chem 71]

In formula (DI-7-12), m is an integer of 1-12.

Examples of diamine compounds represented by formula (DI-8) are shown below. [chem 72]

Examples of diamine compounds represented by formula (DI-9) are shown below. [chem 73]

Examples of diamine compounds represented by formula (DI-10) are shown below. [chem 74]

Examples of diamine compounds represented by formula (DI-11) are shown below. [chem 75]

Examples of diamine compounds represented by formula (DI-12) are shown below. [chem 76]

Examples of diamine compounds represented by formula (DI-13) are shown below. [chem 77]

[chem 78]

[chem 79]

Examples of diamine compounds represented by formula (DI-14) are shown below. [chem 80]

Examples of diamine compounds represented by formula (DI-15) are shown below. [chem 81]

[chem 82]

Examples of diamine compounds represented by formula (DI-16) are shown below. [chem 83]

Dihydrazine will be described. The following formula (DIH-1) - formula (DIH-3) are mentioned as a known dihydrazide which does not have a side chain.

[chem 84]

In the formula (DIH-1), G ²⁵ is a single bond, an alkylene group with 1 to 20 carbons, -CO-, -O-, -S-, -SO ₂ -, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -. In the formula (DIH-2), the ring D is a cyclohexane ring, a benzene ring or a naphthalene ring, and at least one hydrogen of the said group may be substituted by a methyl group, an ethyl group or a phenyl group. In the formula (DIH-3), the ring E is independently a cyclohexane ring or a benzene ring, at least one hydrogen of the said group can be substituted by a methyl group, an ethyl group or a phenyl group, Y is a single bond, and the carbon number is 1 to 1. 20 alkylene group, -CO-, -O-, -S-, -SO ₂ -, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -. In formula (DIH-2) and formula (DIH-3), the bonding position of -CONHNH ₂ bonded to the ring is arbitrary.

式（DIH-1-2）中，m為1～12的整數。 Examples of formula (DIH-1) to formula (DIH-3) are shown below. [chem 85]

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

[chem 86]

[chem 87]

Such non-side chain type diamine and dihydrazide have the effect of improving electrical characteristics such as reducing the ion density of a liquid crystal display element. In the use of non-side chain type diamine and/or dihydrazide as the dihydric liquid crystal alignment agent used in the manufacture of the liquid crystal alignment agent containing polyamic acid, polyamic acid ester or polyimide In the case of an amine compound, it is preferable that the proportion of the non-side chain type diamine and/or dihydrazide in the total amount of the diamine compound be set to 0 mol% to 90 mol%, more preferably set to 0 mol % to 50 mol %.

The side chain type diamine is demonstrated. As a side chain group of a side chain type diamine compound, the following groups are mentioned.

As the side chain group, firstly, alkyl, alkoxy, alkoxyalkyl, alkylcarbonyl, alkylcarbonyloxy, alkoxycarbonyl, alkylaminocarbonyl, alkenyl, alkenyloxy, Alkenylcarbonyl, alkenylcarbonyloxy, alkenyloxycarbonyl, alkenylaminocarbonyl, alkynyl, alkynyloxy, alkynylcarbonyl, alkynylcarbonyloxy, alkynyloxycarbonyl, alkynylaminocarbonyl and the like. The alkyl group, alkenyl group and alkynyl group in these groups are all groups having 3 or more carbon atoms. Among them, in the alkoxyalkyl group, it is sufficient that the carbon number of the whole group is 3 or more. These groups may be linear or branched.

Next, on the condition that the terminal ring has an alkyl group with 1 or more carbons, an alkoxy group with 1 or more carbons, or an alkoxyalkyl group with 2 or more carbons as a substituent, examples include: phenyl, phenylalkyl , phenylalkoxy, phenoxy, phenylcarbonyl, phenylcarbonyloxy, phenoxycarbonyl, phenylaminocarbonyl, phenylcyclohexyloxy, cycloalkyl with 3 or more carbon atoms, cyclohexyl Alkyl, cyclohexyloxy, cyclohexyloxycarbonyl, cyclohexylphenyl, cyclohexylphenylalkyl, cyclohexylphenoxy, bis(cyclohexyl)oxy, bis(cyclohexyl)alkyl, bis( Cyclohexyl)phenyl, bis(cyclohexyl)phenylalkyl, bis(cyclohexyl)oxycarbonyl, bis(cyclohexyl)phenoxycarbonyl and cyclohexylbis(phenyl)oxycarbonyl, etc. .

Furthermore, ring-aggregating groups that have two or more benzene rings, two or more cyclohexane rings, or two or more rings including benzene rings and cyclohexane rings, two The rings are connected by a bonding group, which is independently a single bond, -O-, -COO- (except -COO- which is bonded to the benzene ring at -O-), -OCO- (except -OCO- bonded to the benzene ring at -O-), -CONH-, or an alkylene group with 1 to 3 carbons, and the terminal ring has an alkyl group with 1 or more carbons, and an alkyl group with 1 or more carbons A fluorine-substituted alkyl group, an alkoxy group with 1 or more carbons, or an alkoxyalkyl group with 2 or more carbons as a substituent. A group having a steroid skeleton is also effective as a side chain group.

As a diamine compound which has a side chain, the compound represented by following formula (DI-31) - a formula (DI-35) is mentioned. [chem 88]

In formula (DI-31), G ²⁶ is a single bond, -O-, -COO- (bonded with R ²⁵ at -O-), -CO-, -CONH-, -CH ₂ O-, -OCH ₂ -, -CF ₂ O-, -OCF ₂ - or -(CH ₂ ) _m' -, m' is an integer of 1-12. Preferable examples of ^G26 are single bond, -O-, -COO- (bonding with ^R25 at -O-), _-CH2O- , and alkylene groups with 1 to 3 carbon atoms, particularly preferred examples is a single bond, -O-, -COO-, -CH ₂ O-, -CH ₂ - and -CH ₂ CH ₂ -. R ²⁵ is an alkyl group having 3 to 30 carbon atoms, a phenyl group, a group having a steroid skeleton, or a group represented by the following formula (DI-31-a). In the alkyl group, at least one hydrogen may be substituted by -F, and at least one -CH ₂ - may be substituted by -O-, -CH=CH- or -C≡C-. The hydrogen of the phenyl group can be passed through -F, -CH ₃ , -OCH ₃ , -OCH ₂ F, -OCHF ₂ , -OCF ₃ , an alkyl group with 3 to 30 carbons or an alkoxy group with 3 to 30 carbons replace. The bonding position of -NH ₂ bonded to the benzene ring means any position on the ring, and the bonding position is preferably meta-position or para-position. That is, when the bonding position of the group "R ²⁵ -G ²⁶ -" is defined as 1-position, the two bonding positions are preferably 3-position and 5-position or 2-position and 5-position. In addition, when G ²⁶ is -COO-, R ²⁵ corresponds to a group other than phenyl, and when it corresponds to formula (DI-31-a), ring B ²¹ corresponds to 1,4-phenylene , pyrimidine-2,5-diyl, pyridine-2,5-diyl, piperidine-1,4-diyl, naphthalene-1,5-diyl, naphthalene-2,7-diyl or anthracene-9 ,10-groups other than diradicals.

[chem 89]

In the formula (DI-31-a), G ²⁷ , G ²⁸ and G ²⁹ are bonding groups, which are independently single bonds or alkylene groups with 1 to 12 carbons, and one or more of the alkylene groups - CH ₂ - can be passed through -O-, -COO- (except for -COO- bonded to the aromatic ring at -O-), -OCO- (except - bonded to the aromatic ring at -O- OCO-), -CONH-, -CH=CH- substitution. Ring B ²¹ , Ring B ²² , Ring B ²³ and Ring B ²⁴ are independently 1,4-phenylene, 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, pyrimidine -2,5-diyl, pyridine-2,5-diyl, piperidine-1,4-diyl, naphthalene-1,5-diyl, naphthalene-2,7-diyl or anthracene-9,10 -Diyl, in ring B ²¹ , ring B ²² , ring B ²³ and ring B ²⁴ , at least one hydrogen may be replaced by -F or -CH ₃ , s, t and u are independently integers from 0 to 2, and their The total is 0 to 5. When s, t or u is 2, the two bonding groups in each parenthesis may be the same or different, and the two rings may be the same or different. R ²⁶ is hydrogen, -F, -OH, alkyl with 1 to 30 carbons, fluorine-substituted alkyl with 1 to 30 carbons, alkoxy with 1 to 30 carbons, -CN, -OCH ₂ F, - OCHF ₂ or -OCF ₃ , at least one -CH ₂ - of the alkyl group having 1 to 30 carbons may be substituted with a divalent group represented by the following formula (DI-31-b).

[chem 90]

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

[chem 91]

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

[chem 92]

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

Specific examples of side chain type diamine compounds are shown below. Examples of the side chain-containing diamines of the formulas (DI-31) to (DI-35) include compounds represented by the following formulas (DI-31-1) to (DI-35-3) .

Examples of the compound represented by the formula (DI-31) are shown below. [chem 93]

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

式（DI-31-12）～式（DI-31-16）中，R ³⁶為碳數4～30的烷基，優選為碳數6～25的烷基。R ³⁷為碳數6～30的烷基，優選為碳數8～25的烷基。 [chem 94]

In formula (DI-31-12) to formula (DI-31-16), R ³⁶ is an alkyl group having 4 to 30 carbons, preferably an alkyl group having 6 to 25 carbons. R ³⁷ is an alkyl group having 6 to 30 carbons, preferably an alkyl group having 8 to 25 carbons.

[chem 95]

[chem 96]

[chem 97]

[chem 98]

[chem 99]

In formula (DI-31-17) to formula (DI-31-37), R ³⁸ is an alkyl group with 1 to 20 carbons or an alkoxy group with 1 to 20 carbons, preferably an alkane with 3 to 20 carbons group or an alkoxy group with 3 to 20 carbon atoms. R ³⁹ is hydrogen, -F, alkyl with 1 to 30 carbons, alkoxy with 1 to 30 carbons, -CN, -OCH ₂ F, -OCHF ₂ or -OCF ₃ , preferably with 3 to 25 carbons alkyl or alkoxy having 3 to 25 carbons. Furthermore, ^G33 is an alkylene group having 1 to 20 carbon atoms.

[chemical 100]

[Chemical 101]

[chemical 102]

[chem 103]

[chemical 104]

Examples of the compound represented by the formula (DI-32) are shown below. [chemical 105]

Examples of compounds represented by formula (DI-33) are shown below. [chemical 106]

[chemical 107]

Examples of compounds represented by formula (DI-34) are shown below. [chemical 108]

[chemical 109]

[chemical 110]

[chem 111]

[chem 112]

In formula (DI-34-1) to formula (DI-34-14), R ⁴⁰ is hydrogen or an alkyl group with 1 to 20 carbons, preferably hydrogen or an alkyl group with 1 to 10 carbons, and R ⁴¹ is hydrogen or an alkyl group having 1 to 12 carbon atoms.

Examples of the compound represented by the formula (DI-35) are shown below. [chem 113]

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

As the diamine compound in the present invention, formula (DI-1-1) ~ formula (DI-16-1), formula (DIH-1-1) ~ formula (DIH-3-6) and formula ( Diamine compounds other than the diamine compounds represented by DI-31-1) to formula (DI-35-3). As such a diamine compound, the compound represented by following formula (DI-36-1) - a formula (DI-36-13) is mentioned, for example.

式（DI-36-1）～式（DI-36-8）中，R ⁴²分別獨立地表示碳數3～30的烷基。 [chem 114]

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

[chem 115]

In formula (DI-36-9) to formula (DI-36-11), e is an integer of 2 to 10, and in formula (DI-36-12), R ⁴³ is independently hydrogen, -NHBoc or -N (Boc) ₂ , at least one of R ⁴³ is -NHBoc or -N(Boc) ₂ , in the formula (DI-36-13), R ⁴⁴ is -NHBoc or -N(Boc) ₂ , and m is 1～ Integer of 12. Here, Boc is tert-butoxycarbonyl.

Among the above-mentioned diamines and dihydrazides, suitable materials for improving various properties will be described.

In the case of emphasizing further improving the alignment of liquid crystals, among the diamines and dihydrazides, it is preferable to use formula (DI-1-3), formula (DI-4-1), formula (DI-5-1 ), formula (DI-5-5), formula (DI-5-9), formula (DI-5-12), formula (DI-5-13), formula (DI-5-29), formula (DI -6-7), compounds represented by formula (DI-7-3) and formula (DI-11-2). More preferably represented by formula (DI-4-1), formula (DI-5-1), formula (DI-5-12), formula (DI-5-13), formula (DI-7-3) diamine. In formula (DI-5-1), m=2, 4 or 6 is preferable, and m=4 is more preferable. In formula (DI-5-12), m=2-6 is preferable, and m=5 is more preferable. In the formula (DI-5-13), m=1 or 2 is preferable, and m=1 is more preferable. In formula (DI-7-3), m=2 or 3 is preferable, and n=1 or 2, and m=1 is more preferable.

When emphasis is placed on improving the transmittance, among the diamines and dihydrazides, it is preferable to use the formula (DI-1-3), formula (DI-2-1), formula (DI-5-1), formula The compound represented by (DI-5-5), formula (DI-5-17), and formula (DI-7-3) is more preferably a diamine represented by formula (DI-2-1). In formula (DI-5-1), m=2, 4 or 6 is preferable, and m=4 is more preferable. In formula (DI-7-3), m=2 or 3 is preferable, and n=1 or 2, and m=1 is more preferable.

When paying attention to improving the VHR of the liquid crystal display element, among the above-mentioned diamines and dihydrazides, it is preferable to use the formula (DI-2-1), the formula (DI-4-1), the formula (DI-4-2 ), formula (DI-4-10), formula (DI-4-15), formula (DI-5-1), formula (DI-5-28), formula (DI-5-30), formula (DI -13-1) and the compound represented by formula (DI-31-56), more preferably formula (DI-2-1), formula (DI-5-1), formula (DI-13-1) and formula Compounds represented by (DI-31-56). In formula (DI-5-1), m=1 is preferable. In formula (DI-5-30), k=2 is preferable.

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

In each diamine, a part of the diamine compound may be substituted with a monoamine within the range in which the ratio of the monoamine to the diamine is 40 mol % or less. Such substitution can cause the termination of the polymerization reaction when producing polyamic acid, and can inhibit the further progress of the polymerization reaction. Therefore, through this substitution, the molecular weight of the obtained polymer (polyamic acid, polyamic acid ester or polyimide) can be easily controlled, for example, the performance of the liquid crystal alignment agent can be improved without compromising the effect of the present invention. coating properties. As long as the effects of the present invention are not impaired, the diamine compound substituted with the monoamine may be one type or two or more types. Examples of the monoamine include: aniline, 4-hydroxyaniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-decylamine, Monoamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine and n-eicosylamine.

Polyamic acid and its derivatives may also contain monoisocyanate compounds in their monomers. By containing the monoisocyanate compound in the monomer, the terminal of the obtained polyamic acid or its derivative is modified and the molecular weight is adjusted. By using the terminal-modified polyamic acid or its derivatives, for example, the coating properties of the liquid crystal alignment agent can be improved without impairing the effects of the present invention. From these viewpoints, the content of the monoisocyanate compound in the monomer is preferably 1 mol % to 10 mol % with respect to the total amount of the diamine compound and the tetracarboxylic acid derivative in the monomer. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

Polyamic acid and its derivatives can be obtained by reacting the tetracarboxylic acid derivative and a diamine compound in a solvent. In the synthesis reaction, no special conditions are required except for the selection of raw materials, and the conditions in general polyamic acid synthesis can be directly applied. The solvent used will be described below.

Polyamic acid or derivatives thereof can be produced in the same manner as known polyamic acid or derivatives thereof used for forming a polyimide film. The total charged amount of the tetracarboxylic acid derivative is preferably approximately equimolar to the total molar number of diamine compounds (the molar ratio is about 0.9 to 1.1).

The molecular weight of the polyamic acid or its derivative is preferably 7,000 to 500,000, more preferably 10,000 to 200,000 in terms of polystyrene-equivalent weight average molecular weight (Mw). The molecular weight of the polyamic acid or its derivative can be determined by measurement by gel permeation chromatography (GPC).

The presence of the polyamic acid or its derivative can be confirmed by analyzing the solid content obtained by precipitating the polyamic acid or its derivative in a large amount of poor solvent by IR or NMR. In addition, the monomers used can be confirmed by using gas chromatography (Gas Chromatography, GC), high performance liquid chromatography (High Performance Liquid Chromatography, HPLC) or gas chromatography-mass spectrometry (Gas Chromatography-Mass Spectrometry, GC-MS) analysis of the extract extracted from the decomposition product using an organic solvent after decomposing the polyamic acid or its derivatives using an aqueous solution of a strong base such as KOH or NaOH.

The liquid crystal alignment agent of the present invention may further contain polymers other than the polyamic acid of the present invention or its derivatives. The other components may be one kind or two or more kinds.

Examples of other polymers include: polyesters, polyamides, polysiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-phenylmaleimide) Derivatives, poly(meth)acrylates, etc. One type may be used, or two or more types may be used. Among these, other polyamic acid or derivatives thereof and polysiloxane are preferred, and other polyamic acid or derivatives thereof are more preferred.

As the polysiloxane, JP-A-2009-036966, JP-A-2010-185001, JP-A-2011-102963, JP-A-2011-253175 , Japanese Patent Laid-Open No. 2012-159825, International Publication No. 2008/044644, International Publication No. 2009/148099, International Publication No. 2010/074261, International Publication No. 2010/074264, International Publication No. 2010/126108 , the polysiloxane disclosed in International Publication No. 2011/068123, International Publication No. 2011/068127, International Publication No. 2011/068128, International Publication No. 2012/115157, International Publication No. 2012/165354, etc.

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

[Alkenyl Substituted Nadicimide Compounds] The liquid crystal alignment agent of the present invention may further contain an alkenyl-substituted nadicimide compound for the purpose of stabilizing the electrical characteristics of the liquid crystal display element over a long period of time. One type of alkenyl-substituted nadicimide compound may be used, or two or more types may be used in combination. For the purpose, the content of the alkenyl-substituted nadicimide compound is preferably 1 to 50 parts by mass relative to 100 parts by mass of the total amount of the amide acid-based compound and polyamic acid or derivatives thereof, More preferably, it is 1-30 mass parts, More preferably, it is 1-20 mass parts. The alkenyl-substituted nadicimide compound is preferably a compound that is soluble in a solvent that dissolves the amic acid-based compound and polyamic acid or a derivative thereof used in the present invention. Preferred alkenyl-substituted nadicimide compounds include alkenyl-substituted sodium compounds disclosed in JP-A-2008-096979, JP-A-2009-109987, and JP-A-2013-242526. dicimide compound. As a particularly preferable alkenyl-substituted nadicimide compound, bis{4-(allylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide)phenyl} Methane, N,N'-m-xylylene-bis(allylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide), N,N'-hexamethylene - bis(allylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide).

[Compounds having radically polymerizable unsaturated double bonds] The liquid crystal alignment agent of the present invention may further contain a compound having a radically polymerizable unsaturated double bond for the purpose of stabilizing the electrical characteristics of the liquid crystal display element over a long period of time. The compound having a radically polymerizable unsaturated double bond may be one kind of compound, or two or more kinds of compounds. In addition, no alkenyl-substituted nadicimide compound is included in the compound having a radically polymerizable unsaturated double bond. Among compounds having a radically polymerizable unsaturated double bond, preferred compounds include: N,N'-methylenebisacrylamide, N,N'-dihydroxyethylidene-bisacrylamide , ethylene diacrylate and 4,4'-methylene bis(N,N-dihydroxyethyl acrylate aniline), triallyl cyanurate; and Japanese Patent Laid-Open No. 2009-109987 , Japanese Patent Application Laid-Open No. 2013-242526, International Publication No. 2014/119682, and International Publication No. 2015/152014 are compounds having a radically polymerizable unsaturated double bond. For the purpose, the content of the compound having a radically polymerizable unsaturated double bond is preferably 1 to 50 parts by mass relative to 100 parts by mass of the total amount of the amide acid-based compound and polyamic acid or derivatives thereof parts, more preferably 1 to 30 parts by mass.

[Oxazine Compounds] The liquid crystal alignment agent of the present invention may further contain an oxazine compound for the purpose of stabilizing the electrical characteristics of the liquid crystal display element over a long period of time. The oxazine compound may be one kind of compound, or two or more kinds of compounds. For the purpose, the content of the oxazine compound is preferably 0.1 to 50 parts by mass, more preferably 1 part by mass, based on 100 parts by mass of the total amount of the amide acid-based compound and polyamic acid or derivatives thereof -40 parts by mass, more preferably 1 -20 parts by mass.

The oxazine compound is preferably a ring-opening polymerizable oxazine compound that is soluble in a solvent for dissolving the amide acid-based compound and polyamic acid or a derivative thereof. Preferable oxazine compounds include oxazine compounds represented by formula (OX-3-1), formula (OX-3-9), and formula (OX-3-10); and Japanese Patent Laid-Open No. 2007-286597 2013-242526, and the oxazine compound disclosed in Japanese Patent Application Laid-Open No. 2013-242526. [chem 116]

[Oxazoline compounds] The liquid crystal alignment agent of the present invention may further contain an oxazoline compound for the purpose of stabilizing the electrical characteristics of the liquid crystal display element over a long period of time. The oxazoline compound is a compound having an oxazoline structure. The oxazoline compound may be one kind of compound, or two or more kinds of compounds. For the purpose, the content of the oxazoline compound is preferably 0.1 to 50 parts by mass, more preferably 1 part by mass, relative to 100 parts by mass of the total amount of the amide acid-based compound and polyamic acid or derivatives thereof. part to 40 parts by mass, more preferably 1 part to 20 parts by mass. Preferable oxazoline compounds include oxazoline compounds disclosed in JP-A-2010-054872 and JP-A-2013-242526. More preferably, 1,3-bis(4,5-dihydro-2-oxazolyl)benzene is mentioned.

[epoxy compounds] The liquid crystal alignment agent of the present invention may further contain an epoxy compound for the purpose of stabilizing the electrical characteristics of the liquid crystal display element over a long period of time, for the purpose of increasing the hardness of the film, or for the purpose of improving the adhesion with the sealant. The epoxy compound may be one kind of compound, or two or more kinds of compounds. For the purpose, the content of the epoxy compound is preferably 0.1 to 50 parts by mass, more preferably 1 part by mass, based on 100 parts by mass of the total amount of the amide acid-based compound and polyamic acid or derivatives thereof -20 parts by mass, more preferably 1 -10 parts by mass.

As the epoxy compound, various compounds having one or two or more epoxy rings in the molecule can be used.

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

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

[Silane compound] The liquid crystal alignment agent of this invention may further contain a silane compound for the purpose of improving the adhesiveness with a board|substrate and a sealant. For the purpose, the content of the silane compound is preferably 0.1 to 30 parts by mass, more preferably 0.5 parts by mass, relative to the total amount (100 parts by mass) of the amide acid-based compound and polyamic acid or its derivatives. 20 parts by mass, more preferably 0.5 parts by mass to 10 parts by mass.

[other] Examples of the polymer compound include polymer compounds soluble in organic solvents. From the viewpoint of controlling the electrical properties or alignment of the formed liquid crystal alignment film, it is preferable to add such a polymer compound to the liquid crystal alignment agent of the present invention. Examples of the polymer compound include polyamide, polyurethane, polyurea, polyester, polyepoxide, polyester polyol, silicone-modified polyurethane, and silicone Ketone modified polyester.

As the low-molecular compound, for example, 1) when it is desired to improve coatability, a surfactant suitable for the above purpose can be mentioned; 2) when it is necessary to improve antistaticity, an antistatic agent can be mentioned; For the adhesiveness, a silane coupling agent or a titanium-based coupling agent is used, and 4) when imidization is performed at a low temperature, an imidization catalyst is used.

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

As the solvent, there may be mentioned an amic acid-based compound or a pro-solvent of the polymer used (the polyamic acid or its derivatives, etc.), or other solvents for the purpose of improving coatability.

Examples of aprotic polar organic solvents that are solvophilic to amide acid-based compounds and polyamic acid or derivatives thereof include: N-methyl-2-pyrrolidone, dimethyl imidazolidinone (dimethyl imidazolidinone) , N-methylcaprolactamide, N-methylacrylamide, N,N-dimethylacetamide, dimethylsulfide, N,N-dimethylformamide (N,N- Dimethyl formamide, DMF), N,N-diethylformamide, diethylacetamide, γ-butyrolactone and other lactones.

It is particularly preferable to use at least one solvent selected from the group consisting of alcohols, ethers, and ketones as other solvents for the purpose of improving applicability and the like.

Examples of the alcohol include butyl cellosolve (ethylene glycol monobutyl ether), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monopropylene Ether, 1-butoxy-2-propanol, 2-(2-methoxypropoxy)propanol, ethyl lactate, methyl lactate, propyl lactate, butyl lactate, etc.

Examples of the ether include: alkanediol dialkyl ethers such as ethylene glycol dimethyl ether and ethylene glycol diethyl ether; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl Ethyl ether, diethylene glycol butyl methyl ether and other dialkyl glycol dialkyl ethers; Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether and other dialkyl dialkyl ethers Alcohol monoalkyl ether; Ethylene glycol monobutyl ether acetate, Propylene glycol monoethyl ether acetate, Ethylene glycol monoethyl ether acetate, Diethylene glycol monomethyl ether acetate, Diethylene glycol monoethyl ether Acetate, ethylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, etc. Glycol alkyl ether acetate; propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate, propylene glycol monopropyl ether propionate, propylene glycol monobutyl ether propionate, etc. propylene glycol monoalkyl ether propionate; tetrahydrofuran and other cyclic ethers.

Examples of the ketone include methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, methyl isoamyl ketone, diisobutyl Ketone, methyl-3-methoxypropionate, etc.

Among these, the solvent is particularly preferably N-methyl-2-pyrrolidone, dimethyl imidazolidinone, γ-butyrolactone, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monobutyl ether, Propylene Glycol Monomethyl Ether, Dipropylene Glycol Monomethyl Ether, Diethylene Glycol Diethyl Ether, and 1-butoxy-2-propanol.

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

The viscosity of the liquid crystal alignment agent of the present invention differs in the preferred range depending on the coating method, the concentration of the amide acid compound, the presence or absence of polymers, the type, and the type and ratio of the solvent. For example, when applying by a printing machine, it is preferably 5 mPa·s to 100 mPa·s (more preferably 10 mPa·s to 80 mPa·s). If it is 5 mPa·s or more, sufficient film thickness will be easily obtained, and if it is 100 mPa·s or less, printing unevenness will become small. When applying by the spin coating method, it is preferably 5 mPa·s to 200 mPa·s (more preferably 10 mPa·s to 100 mPa·s). When coating is performed using an inkjet coating device, it is preferably 5 mPa·s to 50 mPa·s (more preferably 5 mPa·s to 20 mPa·s). The viscosity of the liquid crystal alignment agent can be measured by rotational viscometry, for example, by using a rotational viscometer (TVE-20L type manufactured by Toki Sangyo) (measurement temperature: 25° C.).

＜＜Liquid crystal alignment film＞＞ The liquid crystal alignment film of the present invention will be described in detail. The liquid crystal alignment film of the present invention is a film formed by heating the coating film of the liquid crystal alignment agent of the present invention. The liquid crystal alignment film of the present invention can be obtained by a common method of producing a liquid crystal alignment film from a liquid crystal alignment agent. For example, the liquid crystal alignment film of the present invention can be obtained through the following steps: the step of forming the coating film of the liquid crystal alignment agent of the present invention, the step of heating and drying the coating film to form a film of the liquid crystal alignment agent, and the step of forming a film of the liquid crystal alignment agent. A step of imparting anisotropy by irradiating the film with light, and a step of heating and sintering the film of the liquid crystal alignment agent imparted with anisotropy.

A coating film can be formed by applying the liquid crystal alignment agent of this invention to the board|substrate in a liquid crystal display element similarly to preparation of a normal liquid crystal alignment film. Substrates can include indium tin oxide (Indium Tin Oxide, ITO), indium zinc oxide ( _{In2O3 -} ZnO, IZO), indium gallium zinc oxide (In-Ga- _ZnO4 , IGZO) electrodes or color Glass substrates such as optical filters.

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

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

The heating and sintering step is carried out under the conditions required for the imidization reaction of the amide acid compound. Therefore, in this step, the imidization reaction of the amide acid-based compound is carried out. Furthermore, in the liquid crystal alignment agent containing polyamic acid or its derivatives, the imidization reaction of the dehydration-ring-closing reaction of polyamic acid or its derivatives should also be performed in said process. In addition, as described above, in the compound having a hydroxyl group, the compound having a carboxyl group, and the compound having both, which are amide acid-based compounds, esterification may also be performed in the kneading step.

Generally known methods for firing the coating film include heat treatment in an oven or an infrared furnace, heat treatment on a hot plate, and the like. These methods can also be similarly applied to the present invention. Usually, it is preferable to carry out at a temperature of about 100°C to 300°C for 1 minute to 3 hours, more preferably 120°C to 280°C, still more preferably 150°C to 250°C.

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

The method for forming the liquid crystal alignment film of the present invention using the photo-alignment method will be described in detail. The liquid crystal alignment film of the present invention using the photo-alignment method can be formed by irradiating linearly polarized light or non-polarized light of radiation to the film after heating and drying the coating film to impart anisotropy to the film, and to The film is heated and baked. Alternatively, it can be formed by heat-drying the coating film, heating the film, and then irradiating the film with linearly polarized light or non-polarized light of radiation. From the viewpoint of alignment, the step of irradiating radiation is preferably performed before the step of heating and firing.

Furthermore, in order to improve the liquid crystal alignment ability of a liquid crystal alignment film, you may irradiate linearly polarized light or non-polarized light of a radiation, heating a coating film. Irradiation with radiation may be performed in the step of heating and drying the coating film, or in the step of heating and baking the coating film, or may be performed between the heating and drying step and the heating and burning step. The heating and drying temperature in the step is preferably in the range of 30°C to 150°C, more preferably in the range of 50°C to 120°C. In addition, the heating and calcining temperature in the step is preferably in the range of 30°C to 300°C, more preferably in the range of 50°C to 250°C.

As the radiation, for example, ultraviolet light or visible light including light having a wavelength of 150 nm to 800 nm, preferably ultraviolet light including light having a wavelength of 200 nm to 300 nm, can be used. In addition, linearly polarized light or non-polarized light can be used. These lights are not particularly limited as long as they can impart liquid crystal alignment ability to the film, but are preferably linearly polarized light when it is desired to express a strong alignment restriction force on the liquid crystal.

The liquid crystal alignment film of the present invention can exhibit high liquid crystal alignment ability even under low-energy light irradiation. The irradiation dose of linearly polarized light in the radiation irradiation step is preferably 0.05 J/cm ² to 10 J/cm ² , more preferably 0.5 J/cm ² to 1 J/cm ² . In addition, the wavelength of linearly polarized light is preferably 200 nm to 400 nm, more preferably 200 nm to 300 nm. The irradiation angle of linearly polarized light on the film surface is not particularly limited, but it is preferably as perpendicular to the film surface as possible from the viewpoint of shortening the alignment treatment time when a strong alignment restriction force on liquid crystals is to be exhibited. In addition, the liquid crystal alignment film of the present invention can align liquid crystals in a direction at right angles to the polarization direction of linearly polarized light by irradiating linearly polarized light.

Among the light sources used in the step of irradiating linearly polarized light or non-polarized light, ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, deep ultraviolet (Deep UV) lamps, halogen lamps, metal halide lamps, large Power metal halide lamp, xenon lamp, mercury xenon lamp, excimer lamp, KrF excimer laser, fluorescent lamp, light emitting diode (LED) lamp, sodium lamp, microwave discharged electrodeless lamp wait.

The liquid crystal alignment film of the present invention can be suitably obtained by a method further including steps other than the above steps. For example, although the liquid crystal alignment film of the present invention does not require the step of cleaning the film after burning or radiation irradiation with a cleaning solution, a cleaning step may be provided according to other steps.

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

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

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

The liquid crystal alignment film of the present invention is characterized by having particularly large alignment anisotropy. The magnitude of such anisotropy can be evaluated by the method using polarized light IR described in JP-A-2005-275364 and the like. In addition, it can also be evaluated by a method using ellipsometry. Specifically, the retardation value of the liquid crystal alignment film can be measured by a spectroscopic ellipsometer. The retardation value of the film increases in proportion to the degree of alignment of the polymer backbone. That is, a film of a polymer having a large retardation value has a large degree of alignment, and when used as a liquid crystal alignment film, it can be considered that a liquid crystal alignment film having a larger anisotropy has a large alignment restriction for a liquid crystal composition force.

The liquid crystal alignment film of the present invention can be suitably used in a transverse electric field type liquid crystal display element.

The liquid crystal alignment film of the present invention can be used for alignment control of liquid crystal compositions for liquid crystal displays such as smartphones, tablet panels, vehicle monitors, and televisions. In addition to the alignment application of liquid crystal compositions for liquid crystal displays, it can also be used for alignment control of optical compensation materials or other liquid crystal materials. In addition, the liquid crystal alignment film of the present invention has large anisotropy, so it can be used alone as an optical compensation material.

＜＜Liquid crystal display element＞＞ A liquid crystal display element can be manufactured using the liquid crystal alignment film of the present invention. Even when a liquid crystal display element using the liquid crystal alignment film of the present invention is equipped with a high-brightness backlight, it can maintain a high voltage retention rate and achieve high display quality. In the following liquid crystal display element, the liquid crystal alignment film only needs to include the liquid crystal alignment film of the present invention, and the liquid crystal display element includes a pair of substrates arranged opposite to each other, and one of the opposing surfaces of the pair of substrates is formed on one of the opposite surfaces. electrodes on one or both of them, a liquid crystal alignment film formed on each of the opposing surfaces of the pair of substrates, a liquid crystal layer formed between the pair of substrates, a pair of Polarizing film, backlight and driving device.

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

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

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

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

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

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

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

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

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

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

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

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

Hereinafter, an Example and a comparative example are given and the characteristics of this invention are demonstrated more concretely. Materials, usage amounts, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed unless departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the specific examples shown below.

＜Measuring method and evaluation method＞ The measurement method and evaluation method used in this Example are shown below. [Measurement of weight average molecular weight (Mw)] The weight-average molecular weight of polyamic acid was determined by the GPC method using a 2695 separation module and a 2414 differential refractometer (manufactured by Waters), and converted to polystyrene. The obtained polyamide was treated with a phosphoric acid-dimethylformamide (Dimethyl formamide, DMF) mixed solution (phosphoric acid/DMF = 0.6/100: mass ratio) so that the polyamic acid concentration became about 2% by mass. acid to dilute. HSPgel RT MB-M (manufactured by Waters) was used as a column, and the mixed solution was used as a developing solvent, and the measurement was performed under conditions of a column temperature of 50° C. and a flow rate of 0.40 mL/min. As the standard polystyrene, TSK standard polystyrene manufactured by Tosoh Co., Ltd. was used.

[contrast] The contrast of the liquid crystal display element described later was evaluated using a luminance meter (multimedia display tester (3298F, manufactured by Yokogawa Measuring Co., Ltd.). The liquid crystal display element was placed under a polarizing microscope in a crossed Nicols state, and the minimum luminance was measured as black luminance. Next, an arbitrary rectangular wave voltage is applied to the device, and the maximum luminance is measured as white luminance. Let the value of the white luminance/black luminance be contrast. Regarding the contrast ratio, less than 2500 was judged as bad, 2500 or more was judged as acceptable, 3000 or more was judged as good, and 4200 or more was judged as optimum.

[Alternating Current (AC) residual image measurement (evaluation of liquid crystal alignment)] The degree of generation of an afterimage (AC afterimage) due to liquid crystal molecules deviating from the initial alignment direction when the liquid crystal display element was driven for a long time was evaluated by the following method. The brightness-voltage characteristic (B-V characteristic) of the liquid crystal display element mentioned later was evaluated. Let this be the brightness-voltage characteristic before stress: B(before). Next, an alternating current of 4.5 V and 60 Hz was applied to the device for 20 minutes, and then short-circuited for 1 second, and the brightness-voltage characteristic (B-V characteristic) was measured again. Let it be the luminance-voltage characteristic after stress application: B(after). Based on their values, the luminance change rate ΔB (%) was estimated using the following equation. ΔB(%)=[B(after)-B(before)]/B(before)×100 (Formula AC1) These measurements were performed with reference to the International Publication No. 2000/43833 manual. It can be said that the smaller the value of ΔB (%) at a voltage of 0.75 V, the more suppressed the occurrence of AC afterimages. 5.0% or less was judged as acceptable, and 3.0% or less was judged as good.

<Compounds used in this example> The compounds used in this example are shown below. [Tetracarboxylic Acid Derivatives with Photoreactive Structure] [Chem. 117]

[Tetracarboxylic acid derivative without photoreactive structure] [Chem. 118]

[Compounds with one _-NH2 ] [Chem. 119]

[Diamine compound] [Chemical 120]

[solvent] NMP: N-Methyl-2-pyrrolidone (N-Methyl-2-pyrrolidone, NMP) BC: butyl cellosolve (ethylene glycol monobutyl ether)

＜Preparation of varnish＞ The varnish used in this example was prepared according to the following procedure. Here, varnishes A1 to A12 prepared in Preparation Examples 1 to 12 are solutions of amide acid compounds, and varnishes P1 to P3 prepared in Preparation Examples 13 to 15 are solutions of polyamic acid. Varnish P1 is a varnish used after blending with varnish A1.

[Preparation Example 1] Preparation of Varnish A1 Put 7.7 g of a compound (2-3-3) with one -NH ₂ into a 100 mL three-neck flask equipped with a stirring blade and a nitrogen inlet tube, and add 80 g of NMP. Under a nitrogen atmosphere, thereafter, 12.3 g of the tetracarboxylic acid derivative (1-1) was added, heated and stirred at 60° C. for 3 hours, and varnish A1 having a solid content concentration of 20% by mass was obtained.

[Preparation Example 2 to Preparation Example 12] The preparation of varnish A2 to varnish A12 was the same as in Preparation Example 1, except that the tetracarboxylic acid derivative and the compound having one -NH ₂ were changed as shown in Table 1, and the mass % at the time of synthesis. Varnishes A2 to A12 were prepared as described above.

[Table 1] Preparation example varnish Tetracarboxylic acid derivatives [molar ratio] Compounds with one _-NH2 [molar ratio] quality% Preparation Example 1 A1 (1-1) [100] (2-3-3) [200] 20 Preparation example 2 A2 (1-1) [100] (2-3-2) [100] (2-3-4) [100] 25 Preparation example 3 A3 (1-1) [100] (2-3-2) [100] (2-1-2) [100] 25 Preparation Example 4 A4 (1-2) [100] (2-3-2) [100] (2-3-4) [100] 25 Preparation Example 5 A5 (1-1) [100] (2-3-1) [200] 25 Preparation example 6 A6 (1-1) [100] (2-3-10) [200] 25 Preparation Example 7 A7 (1-1) [100] (2-3-2) [100] (2-1-4) [100] 12 Preparation example 8 A8 (1-1) [100] (2-3-7) [200] 12 Preparation Example 9 A9 (1-1) [100] (2-3-8) [200] 12 Preparation Example 10 A10 (1-1) [100] (2-3-2) [100] (2-3-9) [100] 12 Preparation Example 11 A11 (1-1) [75] (AN-4-17), m=4 [25] (2-3-2) [100] (2-3-4) [100] 25 Preparation Example 12 A12 (1-5) [100] (2-3-2) [100] (2-3-4) [100] 25

[Preparation Example 13] Preparation of Varnish P1 Put 2.1 g of the diamine compound (DI-5-1-1) into a 100 mL three-necked flask equipped with a stirring blade and a nitrogen inlet tube, and add 37.5 g of NMP. Under a nitrogen atmosphere, 2.9 g of a tetracarboxylic acid derivative (AN-4-5) was added thereto, followed by stirring at room temperature for 12 hours. Add 37.5 g of NMP and 20 g of BC to it, and heat and stir the solution at 80°C until the weight-average molecular weight of the polymer as the solute becomes the desired weight-average molecular weight, so that the weight-average molecular weight of the solute is about 50000 and the varnish P1 whose solid content concentration is 5 mass %.

[Preparation Example 14 - Preparation Example 15] Preparation of Varnish P2 - Varnish P3 Varnishes P2 to P3 were prepared in the same manner as in Preparation Example 13, except that the tetracarboxylic acid derivative, the diamine compound, and the mass % at the time of synthesis were changed as shown in Table 2.

[Table 2] Preparation example varnish Tetracarboxylic acid derivatives [molar ratio] Diamine compound [molar ratio] quality% mw Preparation Example 13 P1 (AN-4-5) [100] (DI-5-1-1) [100] 5 50000 Preparation Example 14 P2 (1-2) [100] (DI-4-1) [100] 6 37000 Preparation Example 15 P3 (1-1) [100] (DI-5-9) [100] 6 40000

<Preparation of liquid crystal alignment agent and measurement of contrast and AC afterimage> [Example 1] Mix varnish A1 and varnish P1 at a mass ratio of 30:70, and use NMP/BC mixed solution (NMP/BC=1/1 Mass ratio) was diluted and stirred so that the total solid content concentration became 3 mass %, and the liquid crystal alignment agent 1 was prepared. The liquid crystal alignment agent 1 was coated on a glass substrate with FFS electrodes and a glass substrate with column spacers by a spinner method. After coating, the substrate was heated at 60°C for 2 minutes to evaporate the solvent, and then, using Multi-Light ML-501C/B manufactured by Ushio Electric Co., Ltd. The direction is linearly polarized light that irradiates ultraviolet light through a polarizing plate. The exposure energy at this time was measured with an ultraviolet integrated light meter UIT-150 (photoreceiver: UVD-S254) manufactured by Ushio Electric Co., Ltd., so that it became 1.0±0.1 J/cm ² at a wavelength of 254 nm. Adjust exposure time. Thereafter, a sintering treatment was performed at 230° C. for 30 minutes to form an alignment film having a film thickness of about 100 nm. Then, the two substrates on which the alignment films were formed were bonded together so that the surfaces on which the liquid crystal alignment films were formed faced each other, and gaps for injecting the liquid crystal composition were provided between the facing liquid crystal alignment films. At this time, the polarization direction of the linearly polarized light irradiated to each liquid crystal alignment film was made parallel. Negative liquid crystal composition A was injected into these cells to fabricate a liquid crystal cell (liquid crystal display element) with a cell thickness of 5 μm.

物性值：NI 75.7℃；Δε -4.1；Δn 0.101；η 14.5 mPa·s. ＜Negative Liquid Crystal Composition A＞ [Chemical 121]

Physical property value: NI 75.7℃; Δε -4.1; Δn 0.101; η 14.5 mPa·s.

Using the produced liquid crystal cell, contrast and AC afterimage measurements were performed as described above. As a result, the contrast ratio was 3600.

[Example 2] to [Example 12], [Comparative Example 1] to [Comparative Example 2] The varnish shown in Table 3 was used instead of varnish A1 and varnish P1, and the mass % was changed. In the same manner as in Example 1, liquid crystal alignment agent 2 to liquid crystal alignment agent 12 and comparative liquid crystal alignment agent 1 to comparative liquid crystal alignment were prepared. Agent 2. Using each prepared liquid crystal alignment agent, it carried out similarly to Example 1, produced the liquid crystal cell, and performed the measurement of contrast and AC afterimage. Table 3 shows the evaluation results of the liquid crystal alignment agent used in each Example, contrast, and AC afterimage.

[table 3] Example Liquid crystal alignment agent Amino acid based varnish polyamide varnish quality% evaluate No. Mixing ratio No. Mixing ratio contrast AC afterimage (%) Example 1 Liquid crystal alignment agent 1 A1 30 P1 70 3 3600 2.9 Example 2 Liquid crystal alignment agent 2 A2 100 8 4600 2.1 Example 3 Liquid crystal alignment agent 3 A3 100 8 4700 2 Example 4 Liquid crystal alignment agent 4 A4 100 8 3500 2.7 Example 5 Liquid crystal alignment agent 5 A5 100 8 4000 2.4 Example 6 Liquid crystal alignment agent 6 A6 100 8 4200 1.8 Example 7 Liquid crystal alignment agent 7 A7 100 8 3900 1.7 Example 8 Liquid crystal alignment agent 8 A8 100 8 4600 3.5 Example 9 Liquid crystal alignment agent 9 A9 100 8 4500 3.8 Example 10 Liquid crystal alignment agent 10 A10 100 8 4400 1.3 Example 11 Liquid crystal alignment agent 11 A11 100 8 4600 2.6 Example 12 Liquid crystal alignment agent 12 A12 100 8 4600 3.9 Comparative example 1 Compare Liquid Crystal Alignment Agents 1 P2 100 4 2800 4.3 Comparative example 2 Compare Liquid Crystal Alignment Agent 2 P3 100 4 4000 3.8

As shown in Table 3, the contrast ratios of the liquid crystal cells of Examples 1 to 12 using amide acid-based compounds in the liquid crystal alignment film are all above 3000 and the AC afterimages are all below 4%, and they are comparative examples. 1-Comparative example 2 is a good value. From this, it can be seen that the liquid crystal alignment agent derived from an amide acid-based compound contributes more effectively to contrast and AC afterimage than a polymer liquid crystal alignment agent. [industrial availability]

With the liquid crystal alignment agent of the present invention, a liquid crystal alignment film showing excellent liquid crystal alignment can be formed. The liquid crystal display element comprising the liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention exhibits high contrast and is less prone to afterimages caused by long-term use.

none

Claims (14)

A liquid crystal alignment agent, comprising an amide acid-based compound with a photoreactive structure, and in the liquid crystal alignment agent, the amide acid-based compound is composed of a compound having one -NH ₂ and a compound having the photoreactive The structure of tetracarboxylic acid derivatives is the starting material for the synthesis of compounds. The liquid crystal alignment agent according to claim 1, wherein the photoreactive structure is a structure that causes photo-Friesian rearrangement. The liquid crystal alignment agent according to Claim 1, wherein the raw material contains the compound represented by formula (1) as the tetracarboxylic acid derivative; AXQXA (1) In the formula, A is independently represented by any of the following formulas In the following formula, n represents an integer from 1 to 4, and * represents the bonding position;

Q is a divalent group represented by any of the following formulas;

The divalent groups can all have substituents, and the substituents are selected from the group consisting of -CH ₃ , -OCH ₃ , -CF ₃ and -F, and * indicates the bonding position; X are independently - COO-, -NHCOO-, or -OCOO-. The liquid crystal alignment agent as described in Claim 3, wherein in the formula (1), Q is a divalent group represented by any of the following formulas;

Each of the divalent groups may have a substituent, and the substituent is selected from the group consisting of -CH ₃ , -OCH ₃ , -CF ₃ and -F, and * represents a bonding position. The liquid crystal alignment agent according to claim 1, wherein the raw material comprises any of the following compounds as the tetracarboxylic acid derivative;

. The liquid crystal alignment agent according to claim 1, wherein the raw material comprises any of the following compounds as the tetracarboxylic acid derivative;

. The liquid crystal alignment agent according to claim 1, wherein the raw material contains at least one of a compound having a hydroxyl group or a compound having a carboxyl group as the compound having one -NH ₂ . The liquid crystal alignment agent according to claim 1, wherein the raw material includes a compound having a hydroxyl group and a compound having a carboxyl group as the compound having one -NH ₂ . The liquid crystal alignment agent according to any one of claim 1 to claim 8, further comprising a polymer as a reaction product from a raw material comprising tetracarboxylic acid derivatives, and selected from diamines and diamines At least one diamine compound in the group consisting of hydrazine, The polymer does not contain photoreactive structures. The liquid crystal alignment agent according to any one of claim 1 to claim 8 substantially does not contain a polymer. A liquid crystal alignment film formed from the liquid crystal alignment agent described in any one of claim 1 to claim 10. A liquid crystal display element having the liquid crystal alignment film as claimed in claim 11. A method for manufacturing a liquid crystal alignment film is a method for manufacturing a liquid crystal alignment film, and has the following steps: Coating the liquid crystal alignment agent described in any one of claims 1 to 10 on the substrate, irradiating polarized light to the formed film of the liquid crystal alignment agent to impart anisotropy, and then performing a step of heating and burning. A method for manufacturing a liquid crystal display element, comprising forming a liquid crystal alignment film through the method for manufacturing a liquid crystal alignment film as described in Claim 13.