WO2018051923A1

WO2018051923A1 - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element

Info

Publication number: WO2018051923A1
Application number: PCT/JP2017/032542
Authority: WO
Inventors: 石川　和典; 信郁金; 翔一朗中原
Original assignee: 日産化学工業株式会社
Priority date: 2016-09-13
Filing date: 2017-09-08
Publication date: 2018-03-22
Also published as: TW201823436A; KR20190053904A; CN109923469B; JP7089227B2; KR102393693B1; CN109923469A; JPWO2018051923A1

Abstract

A liquid crystal aligning agent which contains the component (A) and the component (B) described below. In the formulae, the symbols are as defined in the description. Component (A): at least one polymer selected from the group consisting of polyimide precursors, which are obtained by reacting a diamine component containing a diamine represented by formula (1) and a tetracarboxylic acid derivative component with each other, and polyimides obtained by closing the rings of the polyimide precursors Component (B): a compound which has two or more partial structures represented by formula (2), while having a molecular weight of 2,500 or less.

Description

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

The present invention relates to a novel liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display element.

Liquid crystal display elements are currently widely used as display devices that are thin and light. Usually, in this liquid crystal display element, a liquid crystal alignment film is used to determine the alignment state of the liquid crystal. *

As the polymer used for the liquid crystal alignment film, polyimide, polyamide, polyamideimide and the like are known, and a liquid crystal alignment agent obtained by dissolving these polymers and their precursors in a solvent is generally used. *

In recent years, large-screen and high-definition liquid crystal televisions have been widely put into practical use, and liquid crystal display elements for such applications are required to have characteristics that can withstand long-term use in harsh use environments. Therefore, the liquid crystal alignment film used there is required to be more reliable than the conventional one. For such a problem, a liquid crystal aligning agent using a specific additive has been proposed (see Patent Document 1).

International Publication No. 2010/074269

Recently, the brightness of the backlight (BL) used in the liquid crystal display element has been further increased, and the stability of the alignment of the liquid crystal alignment film and the electrical characteristics are excellent in light resistance far exceeding the conventional level. Mitigation properties are required.

As a result of intensive studies, the inventors of the present invention are composed of a polyimide precursor obtained by reacting a diamine component containing a diamine having a specific structure with a tetracarboxylic acid derivative component, and a polyimide obtained by ring-closing the polyimide precursor. It has been found that the above-mentioned problems can be achieved by a liquid crystal aligning agent containing a polymer selected from the group and a compound having a specific structure, and the present invention has been achieved. *

The 1st aspect of this invention which achieves the said objective exists in the liquid crystal aligning agent containing the following (A) component and (B) component.
Component (A): selected from the group consisting of a polyimide precursor obtained by reacting a diamine component containing a diamine of formula (1) below with a tetracarboxylic acid derivative component, and a polyimide obtained by ring-closing the polyimide precursor. At least one polymer

(In Formula (1), R ₁ represents hydrogen or a monovalent organic group. Q ₁ represents an alkylene having 1 to 5 carbon atoms. Cy represents an aliphatic group composed of azetidine, pyrrolidine, piperidine, or hexamethyleneimine. It is a divalent group representing a tero ring, and a substituent may be bonded to these ring portions, R ₂ and R ₃ are each independently a monovalent organic group, q and r are each Independently an integer of 0 to 4. However, when the sum of q and r is 2 or more, a plurality of R ₂ and R ₃ have the above definition.)
Component (B): a compound having two or more structures of the following formula (2) and having a molecular weight of 2,500 or less

(In Formula (2), R ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² and R ³ are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or * ³ —CH ₂ —O—R ¹¹ (R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, “* ³ ” represents a bond to the carbon atom to which R ² and R ³ are bonded). , “* ¹ ” and “* ² ” represent a bond with another atom.)

A second aspect of the present invention that achieves the above object is the liquid crystal aligning agent of the first aspect, wherein the diamine of the formula (1) is represented by the following formula (3). *

(In Formula (3), R ₁ is a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group, R ₂ and R ₃ are each independently a hydrogen atom or a methyl group, and Q ₁ is (It is a linear alkylene having 1 to 5 carbon atoms.)

In a third aspect of the present invention that achieves the above object, the content ratio of the diamine represented by the formula (1) is 1 mol% to 80 mol% with respect to 1 mol of the total diamine component. Or the liquid crystal aligning agent of the second embodiment.

According to a fourth aspect of the present invention for achieving the above object, the liquid crystal according to any one of the first to third aspects, wherein the compound of the component (B) is at least one compound selected from the following formulae: In the alignment agent. *

The fifth aspect of the present invention that achieves the above object further includes the polyimide precursor containing a structural unit represented by the following formula (5) as the component (C), according to the first to fourth aspects. In the liquid crystal alignment agent.

(In Formula (5), X ₂ is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ₂ is a divalent organic group derived from a diamine, and R ₄ is a hydrogen atom or a carbon number of 1 to Each of Z ₁ and Z ₂ independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or a carbon number. 2 to 10 alkynyl groups.)

A sixth aspect of the present invention that achieves the above object is the liquid crystal aligning agent according to the fifth aspect, wherein X ₂ in the formula (5) contains a polyimide precursor containing a structural unit having the following structure. is there.

A seventh aspect of the present invention that achieves the above object is a liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of the first to sixth aspects.

The eighth aspect of the present invention that achieves the above object is a liquid crystal display device comprising the liquid crystal alignment film of the seventh aspect.

According to the liquid crystal aligning agent of the present invention, a liquid crystal aligning film having excellent BL resistance, alignment stability and relaxation characteristics can be obtained.

The liquid crystal aligning agent of the present invention contains a component (A) and a component (B). Hereinafter, each constituent requirement will be described in detail.

<(A) component>
The component (A) contained in the liquid crystal aligning agent of the present invention is a polyimide obtained by reacting a diamine component containing a diamine of the following formula (1) (hereinafter also referred to as a specific diamine) and a tetracarboxylic acid derivative component. It is at least one polymer selected from the group consisting of a precursor and a polyimide obtained by ring-closing the polyimide precursor.

In the above formula (1), R ₁ represents hydrogen or a monovalent organic group, preferably a hydrogen atom or a linear alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group. It is.

R ₁ may be a protecting group that undergoes elimination reaction by heat and replaces a hydrogen atom. From the viewpoint of the storage stability of the liquid crystal aligning agent, this protecting group does not desorb at room temperature, and preferably desorbs at 80 ° C. or higher, more preferably 100 ° C. or higher, particularly preferably 150 to 200 ° C. It is preferable to become. Examples thereof include 1,1-dimethyl-2-chloroethoxycarbonyl group, 1,1-dimethyl-2-cyanoethoxycarbonyl group, tert-butoxycarbonyl group, and the like, preferably tert-butoxycarbonyl group.

Q ₁ represents an alkylene group having 1 to 5 carbon atoms, and is preferably a straight-chain alkylene having 1 to 5 carbon atoms for ease of synthesis. Cy is a divalent group representing an aliphatic heterocyclic ring composed of azetidine, pyrrolidine, piperidine, or hexamethyleneimine, and azetidine, pyrrolidine, or piperidine is preferable from the viewpoint of ease of synthesis. In addition, a substituent may be bonded to these ring portions.

R ₂ and R ₃ are each independently a monovalent organic group, and q and r are each independently an integer of 0 to 4. However, when the sum of q and r is 2 or more, the plurality of R ₂ and R ₃ have the above definition. From the viewpoint of ease of synthesis, R ₂ and R ₃ are preferably methyl groups.

In addition, the bonding position of the amino group in the benzene ring constituting the diamine is not limited. However, the amino group is 3-position or 4-position with respect to the nitrogen atom on Cy, and nitrogen in which Q ₁ and R ₁ are bonded. It is preferably in the 3rd or 4th position with respect to the atom, in the 4th position with respect to the nitrogen atom on Cy, and in the 4th position with respect to the nitrogen atom to which Q ₁ and R ₁ are bonded. Is more preferable.

The structure considered to be one of the factors that exert the effect of the present invention is considered to be a structure obtained by removing two primary amino groups from the diamine of the above formula (1) (hereinafter also referred to as a specific structure). Therefore, without using the diamine of the above formula (1), a diamine compound containing two or more specific structures or a tetracarboxylic dianhydride having a specific structure is used for the liquid crystal aligning agent of the present invention. Although it is considered that a specific structure may be introduced into the obtained polymer, it is preferable to use the diamine of the above formula (1) for the convenience of synthesis. *

The diamine represented by the above formula (1) of the present invention is preferably a compound represented by the following formula (3). *

In the above formula (3), R ₁ is a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group. R ₂ and R ₃ are each independently a hydrogen atom or a methyl group. Q ₁ is a linear alkylene having 1 to 5 carbon atoms.

Specific examples of the diamine represented by the above formula (3) include diamines represented by the following formula (3-1) to the following formula (3-10). In the following formula, Boc represents a tert-butoxycarbonyl group. *

<(B) component>
The component (B) contained in the liquid crystal aligning agent of the present invention is a compound having two or more structures of the following formula (2) and having a molecular weight of 2,500 or less.

In the above formula (2), R ¹ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

R ² and R ³ are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or * ³ —CH ₂ —O—R ¹¹ (R ¹¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms). And “* ³ ” represents a bond with the carbon atom to which R ² and R ³ are bonded.), And “* ¹ ” and “* ² ” are a bond with another atom. It represents that.

Examples of the alkyl group having 1 to 3 carbon atoms of R ¹ and R ¹¹ include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. A hydrogen atom or a methyl group is preferable, and a hydrogen atom is more preferable. R ¹ and R ¹¹ may be the same as or different from each other.

Examples of the alkyl group having 1 to 3 carbon atoms of R ² and R ³ include the groups exemplified for R ¹ above. A hydrogen atom, * ³ —CH ₂ —OH, or * ³ —CH ₂ —OCH ₃ is preferred. R ² and R ³ may be the same as or different from each other.

Examples of the group bonded to the nitrogen atom in the formula (2) (hereinafter referred to as “R ⁴ ”) include, for example, a hydrogen atom, a monovalent organic group, or a carbonyl group in the formula (2) and the nitrogen. And divalent organic groups bonded to the atom. Incidentally, when R ⁴ is the divalent organic group to form a ring structure with the nitrogen atom and the carbonyl groups of formula (2).

The number of structures represented by the above formula (2) in the compound of the component (B) of the present invention may be 2 or more, preferably 2 to 8, more preferably 2 to 6 It is. The number of the group “* ⁴ —CH ₂ —O—R ¹ (“ * ⁴ ”indicates a bond with a carbon atom. R ¹ has the same meaning as above.)” Included in the compound (B) is The number is preferably 2 or more per molecule, more preferably 3 to 8, and still more preferably 3 to 6.

Preferred examples of the structure of the above formula (2) include compounds represented by the following formulas (2-1) to (2-6), for example. *

In the above formulas (2-1) to (2-5), “* 1” represents a bond. In the formula (2-5), R ⁵ is an alkyl group having 1 to 3 carbon atoms. In the above formula (2-6), “* ¹ ” and “* ⁵ ” indicate a bond that is bonded to a group that forms a ring together with the nitrogen atom and carbonyl group in the above formula (2-6). .

Compound (B) has a molecular weight of 2,500 or less. From the viewpoint of improving the solubility in a solvent and the coating property of the liquid crystal aligning agent, the molecular weight is preferably 2,000 or less, and more preferably 1,200 or less. *

Specific examples of the compound (B) include compounds represented by the following formula, for example. *

The compounding ratio of the compound (B) is preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the total polymer components contained in the liquid crystal aligning agent. The minimum of the more preferable mixture ratio of a compound (B) is 1 weight part or more with respect to a total of 100 weight part of the polymer component contained in a liquid crystal aligning agent, More preferably, it is 3 weight part or more. Moreover, about the upper limit of the said mixture ratio, More preferably, it is 50 weight part or less, More preferably, it is 20 weight part or less. In addition, a compound (B) can be used individually by 1 type or in combination of 2 or more types.

<Polyimide precursor and polyimide>
The polyimide precursor contained in the liquid crystal aligning agent of this invention is a polyimide precursor obtained by reaction of the diamine component containing the diamine represented by the said Formula (1), and a tetracarboxylic-acid derivative component. Here, the polyimide precursor is a polyamic acid or a polyamic acid ester.

Examples of tetracarboxylic acid derivatives include acid dianhydrides, dicarboxylic acid diesters, diester dicarboxylic acid chlorides, and the like. *

The polyamic acid is obtained by reacting a diamine component with an acid dianhydride, and the polyamic acid ester is obtained by reacting the diamine component with a dicarboxylic acid diester or diester dicarboxylic acid chloride. *

The polyimide contained in the liquid crystal aligning agent of the present invention is a polyimide obtained by ring-closing these polyimide precursors, and both are useful as a polymer for obtaining a liquid crystal aligning film. *

The polyimide precursor contained in the liquid crystal aligning agent of the present invention is a polymer containing a structural unit represented by the following formula (4). *

In the above formula (4), X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ₁ is a divalent organic group derived from the diamine of formula (1), and R ₄ is a hydrogen atom. Or an alkyl group having 1 to 5 carbon atoms. In view of easiness of imidization by heating, R ₄ is preferably a hydrogen atom, a methyl group or an ethyl group.

In the diamine component for obtaining the polyimide precursor, the content ratio of the diamine represented by the above formula (1) is not limited, but the more the effects of the present invention can be obtained. The proportion of the diamine represented by the above formula (1) is preferably 1 mol% to 80 mol%, more preferably 5 mol% to 60 mol%, still more preferably 10 mol%, based on 1 mol of all diamine components. Mol% to 40 mol%. *

X ₁ is not particularly limited as long as it is a tetravalent organic group. Two or more kinds of X ₁ may be mixed in the polyimide precursor.

Specific examples of X ₁ include structures of the following formula (X1-1) to the following formula (X1-44). From the viewpoint of availability, the following formulas (X1-1) to (X1-14) are more preferable.

In the above formulas (X1-1) to (X1-4), R ₅ to R ₂₅ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 2 to 6 carbon atoms. An alkenyl group, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, which may be the same or different. From the viewpoint of liquid crystal orientation, R ₅ to R ₂₅ are preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group. Specific examples of the structure of the above formula (X1-1) include structures represented by the following formulas (X1-1-1) to (X1-1-6). The following formula (X1-1-1) is particularly preferable from the viewpoint of liquid crystal alignment and photoreaction sensitivity.

In addition to the above formula (4), the polyimide precursor of the present invention may contain a structural unit represented by the following formula (5) as long as the effects of the present invention are not impaired. In addition, when the liquid crystal aligning agent of this invention contains polyimide precursors other than the polyimide precursor containing the structural unit represented by the said Formula (4), it is a structural unit represented by following formula (5). May be a polyimide precursor. *

In the above formula (5), R ₄ has the same definition as in the above formula (4). X ₂ is a tetravalent organic group, including the preferred examples, and has the same definition as X ₁ in formula (4). However, when the liquid crystal aligning agent of this invention contains the polyimide precursor containing the structural unit of said Formula (5) other than the polyimide precursor containing the structural unit represented by said Formula (4), it is obtained. From the viewpoint of manifesting the effect of the liquid crystal alignment film obtained, the above formula (X1-8) is particularly preferable. Z ₁ and Z ₂ are each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms. is there.

Specific examples of the alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, propyl group, butyl group, t-butyl group, hexyl group, octyl group, decyl group, cyclopentyl group, cyclohexyl group, and bicyclohexyl group. Is mentioned.

Examples of the alkenyl group having 2 to 10 carbon atoms include those in which one or more CH ₂ —CH ₂ present in the alkyl group is replaced with CH═CH. More specifically, vinyl group, allyl group, 1-propenyl group, isopropenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group, 2-hexenyl group, cyclopropenyl group, cyclopentenyl group And cyclohexenyl group.

Examples of the alkynyl group having 2 to 10 carbon atoms include those in which one or more CH ₂ —CH ₂ present in the alkyl group is replaced with C≡C. More specifically, an ethynyl group, 1-propynyl group, 2-propynyl group and the like can be mentioned.

The alkyl group having 1 to 10 carbon atoms, the alkenyl group having 2 to 10 carbon atoms, and the alkynyl group having 2 to 10 carbon atoms can be substituted within a range in which the total carbon number including the substituent does not exceed 10. The ring structure may be formed by a substituent. Note that forming a ring structure with a substituent means that the substituents or a substituent and a part of the mother skeleton are bonded to form a ring structure. *

Examples of substituents include halogen groups, hydroxyl groups, thiol groups, nitro groups, aryl groups, organooxy groups, organothio groups, organosilyl groups, acyl groups, ester groups, thioester groups, phosphate ester groups, amide groups, alkyls. Group, alkenyl group, alkynyl group and the like. *

In general, when a bulky structure is introduced in the polyimide precursor, the reactivity of the amino group and the liquid crystal alignment may be lowered. Therefore, Z ₁ and Z ₂ have a hydrogen atom or a substituent. More preferred is an alkyl group having 1 to 5 carbon atoms, particularly preferably a hydrogen atom, a methyl group or an ethyl group.

In the above formula (5), Y ₂ is a divalent organic group derived from a diamine component other than the above formula (1), and its structure is not particularly limited. Specific examples of Y ₂ include the following formula (Y-1) to the following formula (Y-49) and the following formula (Y-57) to the following formula (Y-114). Two or more diamine components may be mixed.

In the above formula (Y-158) and the above formula (Y-162) to the above formula (Y-165), n is an integer of 1 to 6. *

In the above formula (Y-174), the above formula (Y-175), the above formula (Y-178) and the above formula (Y-179), Boc represents a tert-butoxycarbonyl group.

<Method for producing polyamic acid>
The polyamic acid which is a polyimide precursor used in the liquid crystal aligning agent of the present invention can be obtained by reacting the diamine component containing the diamine of the present invention with a tetracarboxylic acid derivative component.

Specifically, it can be synthesized by reacting tetracarboxylic dianhydride and diamine in the presence of an organic solvent. *

The organic solvent is not particularly limited as long as the generated polyamic acid is soluble. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, γ-butyrolactone and the like. When the solubility of the polyimide precursor is high, it is represented by methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the following formula (D-1) to the following formula (D-3). An organic solvent can be used. *

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

These may be used alone or in combination. Furthermore, even if it is a solvent that does not dissolve the polyamic acid alone, it may be used by mixing with the above solvent as long as the produced polyamic acid does not precipitate. In addition, since water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the generated polyamic acid, it is preferable to use a dehydrated and dried organic solvent as much as possible. *

As a method of mixing a diamine component and tetracarboxylic dianhydride in an organic solvent, a solution in which diamine is dispersed or dissolved in an organic solvent is stirred, and the tetracarboxylic dianhydride is dispersed as it is or in an organic solvent. Alternatively, a method of adding by dissolving, a method of adding diamine to a solution in which tetracarboxylic dianhydride is dispersed or dissolved in an organic solvent, or alternately or simultaneously with tetracarboxylic dianhydride and diamine in an organic solvent. The method of adding etc. is mentioned, Any of these methods may be sufficient. *

The temperature during the synthesis of the polyamic acid can be selected from -20 ° C to 150 ° C, but is preferably in the range of -5 ° C to 100 ° C, more preferably 0 ° C to 80 ° C. . *

The reaction time can be arbitrarily selected in the range longer than the time during which the polymerization of the polyamic acid is stabilized, but is preferably 30 minutes to 24 hours, more preferably 1 hour to 12 hours. *

The reaction can be carried out at any concentration. However, if the concentrations of the raw material diamine component and tetracarboxylic dianhydride are too low, it is difficult to obtain a high molecular weight polymer, and if the concentration is too high, the reaction solution The viscosity becomes too high and uniform stirring becomes difficult, so the content is preferably 1% by mass to 50% by mass, more preferably 5% by mass to 20% by mass. The initial reaction may be carried out at a high concentration, and then an organic solvent may be added. *

In the polyamic acid synthesis reaction, the ratio of the number of moles of tetracarboxylic dianhydride to the number of moles of the diamine component is preferably 0.8 to 1.2. Similar to a normal polycondensation reaction, the closer the molar ratio is to 1.0, the greater the molecular weight of the polyamic acid produced. *

The polyamic acid obtained as described above can be recovered by precipitating a polymer by pouring into a poor solvent while thoroughly stirring the reaction solution. In addition, by performing precipitation several times, washing with a poor solvent, and then drying at normal temperature or heat, a purified polyamic acid powder can be obtained. *

The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve, acetone, toluene and the like, and water, methanol, ethanol, 2-propanol and the like are preferable.

<Manufacture of polyamic acid ester>
The polyamic acid ester which is the polyimide precursor of this invention can be manufactured with the manufacturing method of [1], [2] or [3] shown below.

[1] When producing from polyamic acid The polyamic acid ester can be produced by esterifying the polyamic acid produced as described above.

Specifically, the polyamic acid and the esterifying agent are reacted in the presence of an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C., for 30 minutes to 24 hours, preferably 1 hour to 4 hours. Can be manufactured.

The esterifying agent is preferably one that can be easily removed by purification, and N, N-dimethylformamide dimethyl acetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide Dineopentyl butyl acetal, N, N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p -Tolyltriazene, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride and the like. The addition amount of the esterifying agent is preferably 2 to 6 molar equivalents relative to 1 mol of the polyamic acid repeating unit. *

Examples of the organic solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide or 1,3-dimethyl- Examples include imidazolidinone. When the solubility of the polyimide precursor in the solvent is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the above formulas (D-1) to (D- The solvent shown by 3) can be used. *

Solvents may be used alone or in combination. Furthermore, even if it is a solvent which does not dissolve a polyimide precursor, you may mix and use it for the said solvent in the range which the produced | generated polyimide precursor does not precipitate. Further, since water in the solvent inhibits the polymerization reaction and further causes hydrolysis of the generated polyimide precursor, it is preferable to use a dehydrated and dried solvent. *

The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the solubility of the polymer. These may be used alone or in combination of two or more. Also good. The concentration at the time of production is preferably 1% by mass to 30% by mass, more preferably 5% by mass to 20% by mass, from the viewpoint that polymer precipitation hardly occurs and a high molecular weight product is easily obtained.

[2] When produced by reaction of tetracarboxylic acid diester dichloride and diamine The polyamic acid ester can be produced from a diamine component containing tetracarboxylic acid diester dichloride and the diamine of the present invention.

Specifically, tetracarboxylic acid diester dichloride and diamine are -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, in the presence of a base and an organic solvent, for 30 minutes to 24 hours, preferably 1 hour. It can be produced by reacting for ˜4 hours. *

As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferable because the reaction proceeds gently. The addition amount of the base is preferably 2 to 4 times mol with respect to tetracarboxylic acid diester dichloride, from the viewpoint that it can be easily removed and a high molecular weight product is easily obtained. 3 times mole is more preferable. *

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone from the viewpoint of the solubility of the monomer and polymer, and these may be used alone or in combination. . *

The polymer concentration at the time of production is preferably 1% by mass to 30% by mass, and more preferably 5% by mass to 20% by mass from the viewpoint that polymer precipitation is difficult to occur and a high molecular weight body is easily obtained. *

In addition, in order to prevent hydrolysis of tetracarboxylic acid diester dichloride, the solvent used for the production of polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent external air from being mixed in a nitrogen atmosphere.

[3] When producing from tetracarboxylic acid diester and diamine Polyamic acid ester can be produced by polycondensing a tetracarboxylic acid diester and a diamine component containing the diamine of the present invention.

Specifically, a tetracarboxylic acid diester and a diamine are mixed in the presence of a condensing agent, a base, and an organic solvent at 0 ° C. to 150 ° C., preferably 0 ° C. to 100 ° C., for 30 minutes to 24 hours, preferably 3 It can be produced by reacting for a time to 15 hours. *

Examples of the condensing agent include triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N′-carbonyldiimidazole, dimethoxy-1,3,5-triazinyl Methylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate diphenyl, and the like can be used. The addition amount of the condensing agent is preferably 2 to 3 times mol, more preferably 2 to 2.5 times mol with respect to the tetracarboxylic acid diester. *

As the base, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the base is preferably 2 times mol to 4 times mol, more preferably 2.5 times mol to 3.5 times mol with respect to the diamine component, from the viewpoint of easy removal and high molecular weight. Is more preferable. *

In the above reaction, the reaction proceeds efficiently by adding Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The addition amount of the Lewis acid is preferably 0-fold to 1.0-fold mole, more preferably 0-fold to 0.7-fold mole with respect to the diamine component.

Among the methods for producing the above three polyamic acid esters, the production method [1] or [2] is particularly preferred because a high molecular weight polyamic acid ester is obtained. *

The polymer solution can be precipitated by injecting the polyamic acid ester solution obtained as described above into a poor solvent while stirring well. Precipitation is performed several times, washed with a poor solvent, and then dried at room temperature or by heating to obtain a purified polyamic acid ester powder. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene etc. are mentioned.

<Production method of polyimide>
The polyimide used in the present invention can be produced by imidizing the polyimide precursor.

In the polyimide of the present invention, the cyclization rate (imidization rate) of the amic acid group or the amic acid ester group is not necessarily 100%, and may be arbitrarily adjusted according to the use and purpose. *

Examples of the method for ring-closing the polyimide precursor include thermal imidization in which the polyimide precursor is heated without using a catalyst and catalytic imidation in which a catalyst is used.

When the polyimide precursor is thermally imidized, the polyimide precursor solution is heated to 100 ° C. to 400 ° C., preferably 120 ° C. to 250 ° C., while removing water or alcohol generated by the imidization reaction from the system. It is preferable to do this.

Catalytic imidation of the polyimide precursor can be performed by adding a basic catalyst and an acid anhydride to a polyamic acid solution and stirring at -20 ° C to 250 ° C, preferably 0 ° C to 180 ° C. . The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times the amic acid group, and the amount of the acid anhydride is 1 to 50 mol times the amic acid group, The amount is preferably 3 mole times to 30 mole times. *

Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like, and among them, pyridine is preferable because it has an appropriate basicity for proceeding with the reaction. *

Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Among these, use of acetic anhydride is preferable because purification after completion of the reaction is facilitated. The imidization rate by catalytic imidation can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time. *

When the polymer component is recovered from the polyimide reaction solution, the reaction solution may be poured into a poor solvent and precipitated. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and water. It is preferable that the polymer precipitated in a poor solvent is recovered by filtration, and then dried by normal temperature or reduced pressure at room temperature or by heating.

<Liquid crystal aligning agent>
A liquid crystal aligning agent is a coating liquid for producing a liquid crystal aligning film, and the main component thereof is a composition containing a resin component for forming a resin film and an organic solvent for dissolving the resin component. . In the liquid crystal aligning agent of the present invention, as the resin component, at least one polymer selected from the group consisting of the polyimide precursor described above and a polyimide obtained by ring-closing the polyimide precursor is used.

The concentration of the polymer in the liquid crystal aligning agent can be appropriately changed by setting the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, the content is preferably 1% by mass or more, and from the viewpoint of storage stability of the solution, it is preferably 10% by mass or less. The concentration of the polymer is particularly preferably 2% by mass to 8% by mass. *

All the resin components in the liquid crystal aligning agent may be the polymer of the present invention, or other polymers other than the polymer of the present invention may be mixed. Examples of such other polymers include polyimide precursors and polyimides obtained by using diamines other than those represented by the above formula (1) as the diamine component. *

The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as the polymer component is uniformly dissolved. Specific examples thereof include N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, Examples include 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl sulfoxide, dimethyl sulfone, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, 3-methoxy-N, N-dimethylpropanamide and the like. You may use these 1 type or in mixture of 2 or more types. Moreover, even if it is a solvent which cannot melt | dissolve a polymer component uniformly by itself, if it is a range which a polymer does not precipitate, you may mix with said organic solvent. *

The liquid crystal aligning agent may contain a solvent for improving the coating film uniformity when the liquid crystal aligning agent is applied to the substrate, in addition to the organic solvent for dissolving the polymer component. As such a solvent, a solvent having a surface tension lower than that of the organic solvent is generally used. Specific examples thereof include ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and 1-butoxy-2-propanol. 2-butoxy-1-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2- Acetate, butyl cellosolve acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, diacetone alcohol, polyethylene Glycol diethyl ether, 2,6-dimethyl-4-heptanol, diisobutyl ketone, 4-methoxy-4-methyl-2-pentanone, 4-hydroxy-2-butanone and 2-methyl-2-hexanol, 2- (2- Ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl ester, lactate isoamyl ester and the like. Two or more of these solvents may be used in combination. *

The above solvent is a poor solvent with low resin solubility. These solvents are preferably 5% by mass to 60% by mass and more preferably 10% by mass to 50% by mass of the organic solvent contained in the liquid crystal alignment treatment agent. *

For the liquid crystal aligning agent, in addition to the above, as long as the effects of the present invention are not impaired, the polymer other than the polymer of the present invention, the purpose of changing the electrical properties such as the dielectric constant and conductivity of the liquid crystal aligning film A dielectric or conductive material, a silane coupling agent for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate, a crosslinkable compound for the purpose of increasing the hardness and density of the film when it is made into a liquid crystal alignment film, When baking a coating film, you may add the imidation promoter for the purpose of making the imidation of a polyimide precursor advance efficiently. *

When a crosslinkable compound such as a functional silane-containing compound or an epoxy group-containing compound is contained, the amount thereof is preferably 0.1% by mass to 30 parts by mass with respect to 100 parts by mass of the resin component. The amount is preferably 1% by mass to 20 parts by mass, and particularly preferably 1% by mass to 10% by mass.

<Method for producing liquid crystal alignment film>
The liquid crystal alignment film is a film obtained by applying the liquid crystal aligning agent to a substrate, drying, and baking.

The substrate on which the liquid crystal aligning agent is applied is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, a silicon nitride substrate, an acrylic substrate, a polycarbonate substrate such as a polycarbonate substrate, or the like can be used. In particular, it is preferable to use a substrate on which an ITO electrode or the like for driving a liquid crystal is formed from the viewpoint of simplifying the process. *

In the case of a reflective liquid crystal display element, an opaque object such as a silicon wafer can be used only on one side of the substrate. In this case, a material that reflects light such as aluminum can be used for the electrode. *

Examples of the method for applying the liquid crystal aligning agent include a spin coating method, a printing method, and an ink jet method. In addition, as a method using a coating liquid, there are a dip, a roll coater, a slit coater, a spinner and the like, and these may be used according to the purpose. *

The drying and baking steps after applying the liquid crystal aligning agent can be selected at any temperature and time. Usually, in order to sufficiently remove the organic solvent contained, drying is performed at 50 ° C. to 120 ° C., preferably 50 ° C. to 80 ° C. for 1 minute to 10 minutes, preferably 3 minutes to 5 minutes, and then Firing is carried out at 150 ° C. to 300 ° C., preferably 200 ° C. to 240 ° C. for 5 minutes to 120 minutes, preferably 10 minutes to 40 minutes. *

The thickness of the fired coating film is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may be lowered, so it is 5 nm to 300 nm, preferably 10 nm to 200 nm. *

Examples of a method for aligning the obtained liquid crystal alignment film include a rubbing method and a photo-alignment processing method. For rubbing treatment, rayon cloth, nylon cloth, cotton cloth or the like can be used. Since the liquid crystal alignment film for vertical alignment is difficult to obtain a uniform alignment state by rubbing treatment, it can be used without rubbing when used as a liquid crystal aligning agent for vertical alignment. *

As a specific example of the photo-alignment treatment method, the surface of the coating film is irradiated with radiation deflected in a certain direction, and in some cases, heat treatment is performed at a temperature of 150 ° C. to 250 ° C. to impart liquid crystal alignment ability. A method is mentioned. As the radiation, ultraviolet rays and visible rays having a wavelength of 100 nm to 800 nm can be used. Among these, ultraviolet rays having a wavelength of 100 nm to 400 nm are preferable, and those having a wavelength of 200 nm to 400 nm are particularly preferable. *

Further, in order to improve the liquid crystal orientation, radiation may be irradiated while heating the coated substrate at 50 ° C. to 250 ° C. *

The dose of radiation is ^preferably from 1mJ / cm 2 ~ 10,000mJ / cm 2, 100mJ / cm 2 ~ 5,000mJ / cm 2 is particularly preferred. The liquid crystal alignment film produced as described above can stably align liquid crystal molecules in a certain direction.

In the above, the film irradiated with polarized radiation may then be contact-treated with a solvent containing at least one selected from water and organic solvents. *

The solvent used for the contact treatment is not particularly limited as long as it is a solvent that dissolves decomposition products generated by light irradiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, 3- Examples include methyl methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate and the like. Two or more of these solvents may be used in combination. *

From the viewpoint of versatility and safety, at least one selected from the group consisting of water, 2-propanol, 1-methoxy-2-propanol and ethyl lactate is more preferable. 1-methoxy-2-propanol or ethyl lactate is particularly preferred.

In the present invention, the contact treatment between the film irradiated with polarized radiation and the solution containing the organic solvent is performed by a treatment such that the film and the liquid are sufficiently in contact, such as an immersion treatment or a spraying treatment. It is preferable. Among them, a method of immersing the film in a solution containing an organic solvent, preferably 10 seconds to 1 hour, more preferably 1 minute to 30 minutes is preferable. The contact treatment may be performed at normal temperature or preferably at 10 ° C. to 80 ° C., more preferably at 20 ° C. to 50 ° C. Moreover, a means for enhancing contact such as ultrasonic waves can be applied as necessary. *

After the contact treatment, for the purpose of removing the organic solvent in the solution used, either rinsing or drying with a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, or You can do both. *

Furthermore, the film subjected to the contact treatment with the solvent may be heated at 150 ° C. or higher for the purpose of drying the solvent and reorienting the molecular chains in the film. *

The heating temperature is preferably 150 ° C to 300 ° C. A higher temperature promotes reorientation of molecular chains. However, if the temperature is too high, molecular chains may be decomposed. Therefore, the heating temperature is more preferably 180 ° C. to 250 ° C., and particularly preferably 200 ° C. to 230 ° C. *

If the heating time is too short, the effects of the present invention may not be obtained. If the heating time is too long, the molecular chain may be decomposed, and is preferably 10 seconds to 30 minutes, and preferably 1 minute to 10 minutes. Is more preferable.

<Liquid crystal display element>
The liquid crystal display element is a liquid crystal display element obtained by preparing a liquid crystal cell by a known method after obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention. .

As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. Note that an active matrix liquid crystal display element in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting the image display may be used. *

First, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segment electrode is provided on the other substrate. These electrodes can be ITO electrodes, for example, and are patterned so as to display a desired image. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film can be, for example, a film made of SiO ₂ —TiO ₂ formed by a sol-gel method.

Next, the liquid crystal alignment film of the present invention is formed on each substrate. Next, the other substrate is superposed on one substrate so that the alignment film surfaces face each other, and the periphery is bonded with a sealant. In order to control the substrate gap, a spacer is usually mixed in the sealing material. In addition, it is preferable to spray spacers for controlling the substrate gap on the in-plane portion where no sealing material is provided. A part of the sealing material is provided with an opening that can be filled with liquid crystal from the outside. *

Next, a liquid crystal material is injected into the space surrounded by the two substrates and the sealing material through the opening provided in the sealing material. Thereafter, the opening is sealed with an adhesive. For the injection, a vacuum injection method may be used, or a method utilizing capillary action in the atmosphere may be used. Alternatively, the liquid crystal can be filled by dropping a liquid crystal after drawing a sealing material on the substrate and bonding the liquid crystal under reduced pressure. *

As the liquid crystal material, either a positive liquid crystal material or a negative liquid crystal material may be used. In particular, even when a negative liquid crystal material having a voltage holding ratio lower than that of a positive liquid crystal material is used, the afterimage characteristics are excellent if the liquid crystal alignment film of the present invention is used. *

Next, a polarizing plate is installed. Specifically, a pair of polarizing plates is attached to the surfaces of the two substrates opposite to the liquid crystal layer. By passing through the above process, the liquid crystal display element of this invention is obtained. Since this liquid crystal display element uses the liquid crystal alignment film obtained by the method for producing a liquid crystal alignment film of the present invention as the liquid crystal alignment film, the liquid crystal display element has excellent afterimage characteristics and a high-definition multifunctional mobile phone. (Smartphones), tablet computers, liquid crystal televisions, and the like.

The present invention will be described more specifically with reference to the following examples. However, the present invention is not construed as being limited to these examples. The abbreviations of the compounds to be used hereinafter and the measuring methods of the respective characteristics are as follows.
<Abbreviation of compound>
In the following formula DA-5 and formula DA-6, “Boc” is a tert-butoxycarbonyl group.

<Abbreviation of compound>
DA-7: 1,3-bis (4-aminophenethyl) urea DA-8: 4- (2-methylaminoethyl) aniline NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve GBL: γ-butyrolactone

<Viscosity>
In the synthesis example, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), a sample amount of 1.1 mL, cone rotor TE-1 (1 ° 34 ′, R24), temperature 25 Measured at ° C.

<Production of liquid crystal display element>
First, a substrate with electrodes was prepared. The substrate is a glass substrate having a size of 30 mm × 35 mm and a thickness of 0.7 mm. On the substrate, an IZO electrode having a solid pattern constituting a counter electrode as a first layer is formed. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by the CVD method is formed as the second layer. The second layer SiN film has a thickness of 500 nm and functions as an interlayer insulating film. On the second SiN film, a comb-like pixel electrode formed by patterning an IZO film as the third layer is arranged to form two pixels, a first pixel and a second pixel. ing. The size of each pixel is 10 mm long and about 5 mm wide. At this time, the first-layer counter electrode and the third-layer pixel electrode are electrically insulated by the action of the second-layer SiN film.

The pixel electrode of the third layer has a comb-like shape configured by arranging a plurality of electrode elements having a dogleg shape whose central portion is bent. The width in the short direction of each electrode element is 3 μm, and the distance between the electrode elements is 6 μm. Since the pixel electrode forming each pixel is formed by arranging a plurality of bent-shaped electrode elements in the central portion, the shape of each pixel is not rectangular, but in the central portion like the electrode elements. It has a shape that bends and resembles a bold-faced koji. Each pixel is divided into upper and lower portions with a central bent portion as a boundary, and has a first region on the upper side of the bent portion and a second region on the lower side. *

When the first region and the second region of each pixel are compared, the formation directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode element of the pixel electrode is formed to form an angle of + 10 ° (clockwise) in the first region of the pixel, and the pixel in the second region of the pixel. The electrode elements of the electrode are formed so as to form an angle of −10 ° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotation operation (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode are mutually in the substrate plane. It is comprised so that it may become a reverse direction. *

Next, after the obtained liquid crystal aligning agent is filtered through a 1.0 μm filter, an ITO film is formed on the back surface as the prepared substrate with electrodes and a counter substrate, and a columnar spacer having a height of 4 μm. Each of the glass substrates having was spin-coated. Subsequently, after drying for 5 minutes on an 80 degreeC hotplate, it baked at 230 degreeC for 20 minutes, and obtained the polyimide film on each board | substrate as a 60 nm-thick coating film. The polyimide film is rubbed with a rayon cloth in a predetermined rubbing direction (roll diameter 120 mm, rotation speed 500 rpm, moving speed 30 mm / sec, pushing amount 0.3 mm), and then irradiated with ultrasonic waves in pure water for 1 minute. And dried at 80 ° C. for 10 minutes. *

Then, using the two types of substrates with the liquid crystal alignment film, the rubbing directions are combined so that they are antiparallel, the periphery is sealed leaving the liquid crystal injection port, and an empty cell with a cell gap of 3.8 μm is formed. Produced. A liquid crystal (MLC-2041, manufactured by Merck & Co., Inc.) was vacuum-injected into this empty cell at room temperature, and the injection port was sealed to obtain an anti-parallel alignment liquid crystal cell. The obtained liquid crystal cell constitutes an FFS mode liquid crystal display element. Thereafter, the obtained liquid crystal cell was heated at 120 ° C. for 1 hour and allowed to stand overnight before being used for each evaluation.

<Evaluation of relaxation characteristics of accumulated charge>
The afterimage was evaluated using the following optical system and the like. The prepared liquid crystal cell is installed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the LED backlight is turned on with no voltage applied, so that the brightness of transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted.

Next, a VT curve (voltage-transmittance curve) was measured while applying an AC voltage having a frequency of 30 Hz to the liquid crystal cell, and an AC voltage with a relative transmittance of 23% was calculated as a drive voltage. *

In the afterimage evaluation, a DC voltage of 1 V was applied at the same time while driving the liquid crystal cell by applying an AC voltage of 30 Hz with a relative transmittance of 23%, and the liquid crystal cell was driven for 40 minutes. Thereafter, the applied DC voltage value was set to 0 V, and only the application of the DC voltage was stopped, and the device was further driven for 15 minutes in this state. *

Evaluation was made by defining as “good” when the relative transmittance decreased to 25% or less by 45 minutes after the start of application of the DC voltage. When it took 45 minutes or more for the relative transmittance to drop to 25% or less, the evaluation was defined as “defective”. *

Then, the afterimage evaluation according to the above-described method was performed under a temperature condition in which the temperature of the liquid crystal cell was 23 ° C.

<Stability evaluation of liquid crystal alignment>
Using this liquid crystal cell, an AC voltage of 10 VPP was applied at a frequency of 30 Hz in a constant temperature environment of 60 ° C. for 168 hours. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left as it was at room temperature for one day.

After leaving, the liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal, and the backlight is turned on with no voltage applied so that the brightness of the transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the first pixel became darkest to the angle at which the first region became darkest was calculated as an angle Δ. Similarly, for the second pixel, the second area was compared with the first area, and a similar angle Δ was calculated. Then, the average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal cell. When the value of the angle Δ of the liquid crystal cell exceeded 0.1 degree, it was defined as “defective” and evaluated. When the value of the angle Δ of the liquid crystal cell did not exceed 0.1 degree, it was defined as “good” and evaluated.

<Evaluation of BL resistance>
The produced liquid crystal cell was aged for 1 week on 2000 nits BL. After aging, a voltage of 1 V was applied to the cell at a temperature of 60 ° C. for 60 μsec, the voltage after 100 msec was measured, and the voltage holding ratio was evaluated.

At that time, when the voltage holding ratio was maintained at 80% or more, it was defined as “good”, and when it was less than 80%, it was defined as “bad” and evaluated.

<Evaluation of rubbing resistance>
After apply | coating a liquid crystal aligning agent to an ITO board | substrate and making it dry temporarily, it baked in 230 degreeC IR type oven, and obtained the board | substrate with a liquid crystal aligning film. This liquid crystal alignment film was rubbed with a rayon cloth (roller rotation speed: 1000 rpm, stage moving speed: 20 mm / sec, indentation length: 0.4 mm). This substrate was observed with a microscope, and the film surface with no streaking due to rubbing was evaluated as “good”, and the material with streaks was evaluated as “bad”.

<Synthesis example>
(Synthesis Example 1)
After charging 34.36 g (0.12 mol) of DA-3 into a 500 mL flask equipped with a stirrer and a nitrogen introduction tube, 335.12 g of NMP was added and stirred to dissolve. While stirring this solution under water cooling, 22.77 g (0.10 mol) of CA-1 was added, 83.80 g of NMP was further added, and the mixture was stirred at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-1). Obtained.

(Synthesis Example 2)
After charging 25.20 g (0.088 mol) of DA-3 and 8.77 g (0.022 mol) of DA-6 into a 500 mL flask equipped with a stirrer and a nitrogen introduction tube, 333.97 g of NMP was added and stirred. And dissolved. While stirring this solution under water cooling, 22.96 g (0.11 mol) of CA-1 was added, 326 g of NMP was further added, and the mixture was stirred at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-2). .

(Synthesis Example 3)
After charging 25.20 g (0.088 mol) of DA-3 and 8.72 g (0.022 mol) of DA-5 into a 500 mL flask equipped with a stirrer and a nitrogen introduction tube, 334.28 g of NMP was added and stirred. And dissolved. While stirring this solution under water cooling, 23.06 g (0.11 mol) of CA-1 was added, and 83.57 g of NMP was further added, followed by stirring at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-3). Obtained.

(Synthesis Example 4)
After charging 19.13 g (0.096 mol) of DA-4 into a 500 mL flask equipped with a stirrer and a nitrogen introduction tube, 232.72 g of a solvent (NMP: GBL = 50 wt%: 50 wt%) was added and stirred to dissolve. I let you. While stirring this solution under water cooling, 14.12 g (0.072 mol) of CA-2 was added, and 84.63 g of a solvent (NMP: GBL = 50 wt%: 50 wt%) was further added, followed by stirring for 2 hours. It was. Thereafter, 4.76 g (0.024 mol) of DA-1 was added, and 42.31 g of NMP was added and dissolved by stirring. While stirring under water cooling again, 9.00 g (0.03 mol) of CA-3 was added, and 326 g of a solvent (NMP: GBL = 50 wt%: 50 wt%) was further added, and after stirring for 2 hours, a polyamic acid solution (PAA- 4) was obtained.

(Synthesis Example 5)
After charging 23.91 g (0.12 mol) of DA-4 and 5.95 g (0.03 mol) of DA-1 into a 500 mL flask equipped with a stirrer and a nitrogen inlet tube, add 255.76 g of NMP and stir. And dissolved. While stirring this solution under water cooling, 6.47 g (0.033 mol) of CA-2 was added, and 73.01 g of NMP was further added, followed by stirring for 2 hours. Thereafter, 28.15 g (0.11 mol) of CA-4 was added, 36.54 g of NMP was added, and the mixture was stirred at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-5).

(Synthesis Example 6)
After charging 23.91 g (0.12 mol) of DA-4 and 4.56 g (0.03 mol) of DA-2 into a 500 mL flask equipped with a stirrer and a nitrogen introduction tube, 241.76 g of NMP was added and stirred. And dissolved. While stirring this solution under water cooling, 13.71 g (0.070 mol) of CA-2 was added, and 69.07 g of NMP was further added, followed by stirring for 2 hours. Thereafter, 18.77 g (0.075 mol) of CA-4 was added, 34.54 g of NMP was added, and the mixture was stirred at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-6).

(Synthesis Example 7)
To a 500 mL flask equipped with a stirrer and a nitrogen introduction tube, 28.69 g (0.144 mol) of DA-4 and 7.14 g (0.036 mol) of DA-1 were added, and 296.56 g of NMP was added and stirred. And dissolved. While stirring this solution under water cooling, 16.41 g (0.084 mol) of CA-2 was added, and 84.73 g of NMP was further added, followed by stirring for 2 hours. Then, 22.52 g (0.09 mol) of CA-4 was added, 42.37 g of NMP was added, and the mixture was stirred at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-7).

(Synthesis Example 8)
After charging 18.98 g (0.048 mol) of DA-5 and 14.28 g (0.048 mol) of DA-7 into a 500 mL flask equipped with a stirrer and a nitrogen introduction tube, 312.67 g of NMP was added and stirred. And dissolved. While stirring this solution under water cooling, 20.04 g (0.092 mol) of CA-1 was added, and 78.17 g of NMP was further added, and then stirred at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-8). )

(Synthesis Example 9)
After charging 26.85 g (0.09 mol) of DA-7 and 9.01 g (0.06 mol) of DA-8 into a 500 mL flask equipped with a stirrer and a nitrogen introduction tube, 289.28 g of NMP was added and stirred. And dissolved. While stirring this solution under water cooling, 27.94 g (0.14 mol) of CA-2 was added, and 72.32 g of NMP was further added, followed by stirring for 2 hours to obtain a polyamic acid solution (PAA-9). It was.

(Comparative Example 1)
In a 20-ml sample tube containing a stir bar, 1.51 g of PAA-1 and 6.99 g of PAA-4 are taken, 1.51 g of NMP, 3.13 g of GBL, 6.00 g of BCS, and 1 AD-1. 0.86 g of GBL solution containing wt% was added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-1).

(Comparative Example 2)
In a 20 ml sample tube containing a stir bar, 1.33 g of PAA-1 and 4.27 g of PAA-5 were taken, 4.40 g of NMP, 5.36 g of GBL, 4.00 g of BCS, and 1 AD-1 0.64 g of a GBL solution containing 5% by weight was added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-2).

(Comparative Example 3)
In a 20 ml sample tube containing a stir bar, 1.33 g of PAA-2 and 4.27 g of PAA-6 were taken, 4.40 g of NMP, 5.36 g of GBL, 4.00 g of BCS, and 1 AD-2. 0.64 g of GBL solution containing wt% was added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-3).

(Comparative Example 4)
In a 20 ml sample tube containing a stir bar, 2.00 g of PAA-8 and 6.40 g of PAA-9 are taken, 1.60 g of NMP, 5.04 g of GBL, 4.00 g of BCS, and 1 AD-2. 0.96 g of a GBL solution containing wt% was added and stirred for 30 minutes with a magnetic stirrer to obtain a liquid crystal aligning agent (A-4).

(Example 1)
In a 20 ml sample tube containing a stir bar, 1.33 g of PAA-3 and 4.27 g of PAA-6 were taken, 4.40 g of NMP, 5.36 g of GBL, 4.00 g of BCS, and 1 AD-2. 0.64 g of a GBL solution containing 5% by weight was added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (B-1).

(Example 2)
In a 20 ml sample tube containing a stir bar, 1.33 g of PAA-3 and 4.27 g of PAA-6 were taken, 4.16 g of NMP, 5.36 g of GBL, 4.00 g of BCS, and 1 AD-2. 0.64 g of a GBL solution containing 10% by weight and 0.24 g of an NMP solution containing 10% by weight of AD-3 were added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (B-2).

(Example 3)
In a 20 ml sample tube containing a stir bar, 1.33 g of PAA-3 and 4.27 g of PAA-7 were taken, 4.40 g of NMP, 5.36 g of GBL, 4.00 g of BCS, and 1 AD-2. 0.64 g of GBL solution containing wt% was added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (B-3).

Example 4
In a 20 ml sample tube containing a stir bar, 1.33 g of PAA-3 and 4.27 g of PAA-7 were taken, 4.16 g of NMP, 5.36 g of GBL, 4.00 g of BCS, and 1 AD-2. 0.64 g of a GBL solution containing 10% by weight and 0.24 g of an NMP solution containing 10% by weight of AD-3 were added and stirred for 30 minutes with a magnetic stirrer to obtain a liquid crystal aligning agent (B-4). Using the liquid crystal aligning agent obtained above, BL resistance, relaxation characteristics of accumulated charge, stability of liquid crystal alignment, and rubbing resistance were evaluated. The results are shown in Table 1 below.

As described above, the liquid crystal alignment film of the present invention showed good results in any of rubbing resistance, BL resistance evaluation, liquid crystal alignment stability evaluation, and afterimage disappearance time evaluation.

Claims

Liquid crystal aligning agent containing the following (A) component and (B) component.
Component (A): selected from the group consisting of a polyimide precursor obtained by reacting a diamine component containing a diamine of formula (1) below with a tetracarboxylic acid derivative component, and a polyimide obtained by ring-closing the polyimide precursor. At least one polymer

(In Formula (1), R 1 represents hydrogen or a monovalent organic group. Q 1 represents an alkylene having 1 to 5 carbon atoms. Cy represents an aliphatic group composed of azetidine, pyrrolidine, piperidine, or hexamethyleneimine. It is a divalent group representing a tero ring, and a substituent may be bonded to these ring portions, R 2 and R 3 are each independently a monovalent organic group, q and r are each Independently an integer of 0 to 4. However, when the sum of q and r is 2 or more, a plurality of R 2 and R 3 have the above definition.)
Component (B): a compound having two or more partial structures represented by the following formula (2) and having a molecular weight of 2,500 or less

(In Formula (2), R 1 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R 2 and R 3 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or * 3 —CH 2 —O—R 11 (R 11 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, “* 3 ” represents a bond to the carbon atom to which R 2 and R 3 are bonded). , “* 1 ” and “* 2 ” represent a bond with another atom.)
The liquid crystal aligning agent of Claim 1 by which the diamine of the said Formula (1) is represented by following formula (3).

(In Formula (3), R 1 is a hydrogen atom, a methyl group, or a tert-butoxycarbonyl group, R 2 and R 3 are each independently a hydrogen atom or a methyl group, and Q 1 is (It is a linear alkylene having 1 to 5 carbon atoms.)
3. The liquid crystal aligning agent according to claim 1, wherein a content ratio of the diamine represented by the formula (1) is 1 mol% to 80 mol% with respect to 1 mol of the total diamine component.
The liquid crystal aligning agent of any one of Claims 1-3 whose compound of the said (B) component is at least 1 sort (s) of compound chosen from a following formula.
Furthermore, the liquid crystal aligning agent of any one of Claims 1-4 which contains the polyimide precursor containing the structural unit of following formula (5) as (C) component.

(In Formula (5), X 2 is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y 2 is a divalent organic group derived from a diamine, and R 4 is a hydrogen atom or a carbon number of 1 to Each of Z 1 and Z 2 independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or a carbon number. 2 to 10 alkynyl groups.)
X 2 in the formula (5) contains a polyimide precursor containing a structural unit is the following structural liquid crystal alignment agent according to claim 5.
A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 6.
A liquid crystal display device comprising the liquid crystal alignment film according to claim 7.