JPWO2018051923A1 - Liquid crystal aligning agent, liquid crystal aligning film and liquid crystal display device - Google Patents

Abstract

The liquid crystal aligning agent containing the following (A) component and (B) component. In addition, the definition of the symbol in each following formula is as description in a specification. Component (A): selected from the group consisting of a polyimide precursor obtained by reacting a diamine component containing a diamine of the following formula (1) and a tetracarboxylic acid derivative component, and a polyimide obtained by ring-closing the polyimide precursor At least one kind of polymer [compound 1] (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 [compound 2]

Description

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

  Liquid crystal display devices are currently widely used as display devices that realize thinness and lightness. Usually, in this liquid crystal display element, a liquid crystal alignment film is used to determine the alignment state of the liquid crystal.

  As a polymer used for a liquid crystal aligning film, polyimide, a polyamide, a polyamide imide etc. are known, and the liquid crystal aligning agent which dissolved these polymers and its precursor in a solvent is generally used.

  In recent years, large-screen, high-definition liquid crystal televisions have been widely put to practical use, and liquid crystal display devices in such applications are required to have characteristics that can withstand long-term use in a severe use environment. Therefore, the liquid crystal alignment film used therein is required to be more reliable than the prior art. The liquid crystal aligning agent which used the specific additive with respect to such a subject is proposed (refer patent document 1).

International Publication No. 2010/074269

  Recently, the brightness of the backlight (BL) used in liquid crystal display devices has been further improved, and the alignment stability of the liquid crystal alignment film and the electrical properties are also superior in light resistance and far beyond the conventional level. Relaxation characteristics are required.

  As a result of intensive investigations, the present inventors are composed of a polyimide precursor obtained by reacting a diamine component containing a diamine having a specific structure and 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 made.

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 the following formula (1) and a tetracarboxylic acid derivative component, and a polyimide obtained by ring-closing the polyimide precursor At least one polymer

（式（１）中、Ｒ_１は水素、又は１価の有機基を表す。Ｑ_１は炭素数１乃至５のアルキレンを表す。Ｃｙはアゼチジン、ピロリジン、ピペリジン又はヘキサメチレンイミンからなる脂肪族へテロ環を表す２価の基であり、これらの環部分に置換基が結合されていてもよい。Ｒ_２及びＲ_３は、それぞれ独立に１価の有機基である。ｑ及びｒは、それぞれ独立に０〜４の整数である。但し、ｑとｒの合計が２以上の場合、複数のＲ_２及びＲ_３は、上記定義を有する。）
（Ｂ）成分：下記式（２）の構造を２つ以上有し、かつ分子量が２，５００以下である化合物

(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 consisting of azetidine, pyrrolidine, piperidine or hexamethyleneimine R ₂ and R ₃ are each independently a monovalent organic group, and q and r are each a divalent group representing a hetero ring, and a substituent may be bonded to these ring portions. Independently, it is 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-mentioned 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

（式（２）中、Ｒ^１は水素原子又は炭素数１〜３のアルキル基、Ｒ^２及びＲ^３は、それぞれ独立に、水素原子、炭素数１〜３のアルキル基、又は＊^３−ＣＨ_２−Ｏ−Ｒ^１１（Ｒ^１１は水素原子又は炭素数１〜３のアルキル基を表し、「＊^３」は、Ｒ^２及びＲ^３が結合する炭素原子との結合手を表す。）を表し、「＊^１」及び「＊^２」は、他の原子との結合手であることを表す。）

(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 an alkyl group having 1 to 3 carbon hydrogen or C, ^{"* 3"} represents a bond to the carbon atom ^{to which R 2} and ^{R 3} are attached.) represents the , “* ¹ ” and “* ² ” indicate that they are bonds with other atoms.)

  A second aspect of the present invention for achieving the above object is the liquid crystal aligning agent according to the first aspect, wherein the diamine of the formula (1) is represented by the following formula (3).

（式（３）中、Ｒ_１は、水素原子、メチル基、又はｔｅｒｔ−ブトキシカルボニル基であり、Ｒ_２およびＲ_３は、それぞれ独立して、水素原子又はメチル基であり、Ｑ_１は、炭素数１〜５の直鎖アルキレンである。）

(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 C1-C5 linear alkylene.)

  A third aspect of the present invention for achieving the above object is that the content ratio of the diamine represented by the formula (1) is 1 mol% to 80 mol% with respect to 1 mol of all diamine components. In the liquid crystal aligning agent of the aspect or 2nd aspect of this

  A fourth aspect of the present invention for achieving the above object is 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 formulas It is in the alignment agent.

  According to a fifth aspect of the present invention for achieving the above object, there is further provided, as a component (C), a polyimide precursor containing a structural unit of the following formula (5): It is in the liquid crystal alignment agent.

（式（５）中、Ｘ_２はテトラカルボン酸誘導体に由来する４価の有機基であり、Ｙ_２はジアミンに由来する２価の有機基であり、Ｒ_４は水素原子又は炭素数１〜５のアルキル基であり、Ｚ_１及びＺ_２は、それぞれ独立して、水素原子、置換基を有してもよい炭素数１〜１０のアルキル基、炭素数２〜１０のアルケニル基又は炭素数２〜１０のアルキニル基である。）

(In the 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 Z ₁ and Z ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkenyl group having 2 to 10 carbon atoms, or a carbon number 2-10 alkynyl groups.)

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

  An eighth aspect of the present invention for achieving the above object is a liquid crystal display device having the liquid crystal alignment film of the seventh aspect.

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

  The liquid crystal aligning agent of this invention contains (A) component and (B) component. Each component will be described in detail below.

<(A) component>
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) with 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.

Further, R ₁ may be a protecting group which causes elimination reaction by heat and replaces a hydrogen atom. From the viewpoint of storage stability of the liquid crystal aligning agent, this protective group does not separate at room temperature, and preferably releases at 80 ° C. or higher, more preferably 100 ° C. or higher, particularly preferably 150 to 200 ° C. Is preferred. 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 of 1 to 5 carbon atoms, and is preferably a linear alkylene of 1 to 5 carbon atoms from the viewpoint of ease of synthesis. Cy is a divalent group representing an aliphatic heterocycle consisting of azetidine, pyrrolidine, piperidine or hexamethylene imine, and azetidine, pyrrolidine or piperidine is preferred from the ease of synthesis. In addition, substituents 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, a plurality of R ₂ and R ₃ have the above definitions. For ease of synthesis, preferably, R ₂ and R ₃ are methyl groups.

Further, the bonding position of the amino group in the benzene ring constituting the above diamine is not limited, but the nitrogen at which the amino group is 3 or 4 position to the nitrogen atom on Cy and Q ₁ and R ₁ are respectively bonded It is preferable that it is in the 3- or 4-position to the atom, and it is in the 4-position to the nitrogen atom on Cy, and the 4-position to the nitrogen atom to which Q ₁ and R ₁ are bonded. Is more preferred.

  The structure considered to be one of factors contributing to the effects of the present invention is considered to be a structure in which two primary amino groups are removed from the diamine of the above formula (1) (hereinafter also referred to as a specific structure). Therefore, even if it does not use diamine of the said Formula (1), it is used for the liquid crystal aligning agent of this invention, using the diamine compound which contains 2 or more of specific structures, and tetracarboxylic dianhydride which has a specific structure. It is considered that a specific structure may be introduced into the polymer to be obtained, but for the convenience of synthesis, it is preferable to use the diamine of the above-mentioned formula (1).

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

In the said 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 linear alkylene having 1 to 5 carbon atoms.

  As a specific example of the diamine represented by said Formula (3), the diamine represented by following formula (3-1)-following formula (3-10) can be mentioned, for example. In the following formulae, 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 each independently represent 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 And “* ³ ” represents a bond with a carbon atom to which R ² and R ³ are bonded.) “* ¹ ” and “* ² ” represent a bond with another atom It represents that it is.

The alkyl group having 1 to 3 carbon atoms of R ¹ and ^{R 11,} for example a methyl group, an ethyl group, n- propyl group, an isopropyl group. Preferably it is a hydrogen atom or a methyl group, more preferably a hydrogen atom. R ¹ and R ¹¹ may be the same or different.

The alkyl group having 1 to 3 carbon atoms of R ² and ^{R 3,} include the groups exemplified in the above ^{R 1.} Preferably, it is a hydrogen atom, * ³ -CH ₂ -OH, or * ³ -CH ₂ -OCH ₃ . R ² and R ³ may be the same or different.

Examples of the group bonded to the nitrogen atom in the above formula (2) (hereinafter referred to as “R ⁴ ”) include, for example, a hydrogen atom, a monovalent organic group, or a carbonyl group in the above formula (2) and the nitrogen Examples thereof include divalent organic groups bonded to atoms. When R ⁴ is a divalent organic group, it forms a ring structure with the nitrogen atom and the carbonyl group in the above 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 groups “* ⁴ —CH ₂ —O—R ¹ (“ * ⁴ ”indicates that it is a bond with a carbon atom; R ¹ has the same meaning as that described above) possessed by compound (B) is And preferably 2 or more, more preferably 3 to 8 and still more preferably 3 to 6 per molecule.

  As a preferable specific example of the structure of said Formula (2), the compound etc. which are represented by each of following formula (2-1)-following formula (2-6) are mentioned, for example.

In the above formulas (2-1) to (2-5), "* 1" indicates that it is a bond. Wherein (2-5), ^{R 5} is an alkyl group having 1 to 3 carbon atoms. “* ¹ ” and “* ⁵ ” in the above formula (2-6) indicate that they are a bond to be bonded to a group forming a ring with the nitrogen atom and the carbonyl group in the above formula (2-6) .

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

  As a specific example of a compound (B), the compound etc. which are represented by a following formula are mentioned, for example.

  The compounding ratio of the compound (B) is preferably 0.1 parts by weight to 100 parts by weight with respect to 100 parts by weight in total of the polymer components contained in the liquid crystal aligning agent. The lower limit of the more preferable compounding ratio of the compound (B) is 1 part by weight or more, more preferably 3 parts by weight or more with respect to 100 parts by weight in total of the polymer components contained in the liquid crystal aligning agent. The upper limit of the mixing ratio is more preferably 50 parts by weight or less, and still more preferably 20 parts by weight 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 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 and diester dicarboxylic acid chlorides.

  The polyamic acid is obtained by reacting the diamine component with the acid dianhydride, and the polyamic acid ester is obtained by the reaction of the diamine component with the 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 alignment film.

  The polyimide precursor contained in the liquid crystal aligning agent of this invention is a polymer containing the structural unit represented by 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 a diamine of formula (1), and R ₄ is a hydrogen atom Or it is a C1-C5 alkyl group. From the viewpoint of ease of imidation by heating, R ₄ is preferably a hydrogen atom, a methyl group or an ethyl group.

  In the diamine component for obtaining the said polyimide precursor, although there is no restriction | limiting in the content rate of the diamine represented by the said Formula (1), If there are many, the effect of this invention will be easy to be acquired. 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%, relative to 1 mol of all diamine components. It is mol%-40 mol%.

As long as X ₁ is a tetravalent organic group, it is not particularly limited. In the polyimide precursor, two or more types of X ₁ may be mixed.

If Specific examples of X _1, include the structures represented by the following formula (X1-1) ~ formula (X1-44). From the viewpoint of availability, the following formula (X1-1) to the following formula (X1-14) are more preferable.

In 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 2 to 6 carbon atoms. It is an alkenyl group, a C2-C6 alkynyl group, a C1-C6 monovalent organic group containing a fluorine atom, or a phenyl group, It may be same or different. From the viewpoint of liquid crystal alignment, 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. As a specific structure of said Formula (X1-1), the structure represented by a following formula (X1-1-1)-a following formula (X1-1-6) is mentioned. From the viewpoint of liquid crystal alignment and sensitivity of photoreaction, the following formula (X1-1-1) is particularly preferable.

  Moreover, the polyimide precursor of this invention may contain the structural unit represented by following formula (5) in the range which does not impair the effect of this invention other than said Formula (4). 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 said Formula (4), it is a structural unit represented by following formula (5) It may be a polyimide precursor having

In said Formula (5), R ₄ is the same as the definition of said Formula (4). X ₂ is a tetravalent organic group, which is the same as the definition of X ₁ in the above formula (4), including preferred examples. However, it is obtained when the liquid crystal aligning agent of the present invention contains a polyimide precursor containing the structural unit of the above formula (5) in addition to the polyimide precursor containing the structural unit represented by the above formula (4). From the viewpoint of exhibiting the effect of the liquid crystal alignment film to be produced, the above formula (X1-8) is particularly preferable. Z ₁ and Z ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, 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, bicyclohexyl group, etc. Can be mentioned.

The alkenyl group having 2 to 10 carbon atoms, one or more _CH 2 -CH ₂ present in the alkyl group are replaced with CH = CH may be mentioned. 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.

The alkynyl group having 2 to 10 carbon atoms, are replaced with one or more _CH 2 -CH ₂ present in the alkyl group C≡C the like. More specifically, 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 have a total of not more than 10 carbon atoms including the substituents. It may have, and further, it may form a ring structure by a substituent. In addition, 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 the substituent include a halogen group, a hydroxyl group, a thiol group, a nitro group, an aryl group, an organooxy group, an organothio group, an organosilyl group, an acyl group, an ester group, a thioester group, a phosphate group, an amide group and an alkyl And alkenyl groups and alkynyl groups.

In the polyimide precursor, generally, introducing a bulky structure may reduce the reactivity of the amino group and the liquid crystal alignment, and therefore Z ₁ and Z ₂ have a hydrogen atom or a substituent. An alkyl group having 1 to 5 carbon atoms is more preferable, and a hydrogen atom, a methyl group or an ethyl group is particularly preferable.

In said Formula (5), Y ₂ is a bivalent organic group originating in diamine components other than said Formula (1), The structure is not specifically limited. If Y ₂ Specific examples include the following formulas (Y-1) ~ formula (Y-49) and formula (Y-57) ~ formula (Y-114). Moreover, 2 or more types of diamine components may be mixed.

  In said formula (Y-158), said formula (Y-162)-said formula (Y-165), n is an integer of 1-6.

  Boc in said Formula (Y-174), said Formula (Y-175), said Formula (Y-178), and said Formula (Y-179) represents a tert- butoxycarbonyl group.

<Method of producing polyamic acid>
The polyamic acid which is a polyimide precursor used for the liquid crystal aligning agent of this invention can be obtained by making the diamine component containing the diamine of this invention, and a tetracarboxylic-acid derivative component react.

  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 can be dissolved. Specific examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, γ-butyrolactone and the like. Also, 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) Organic solvents can be used.

In the formula (D-1), ^{D 1} represents an alkyl group having 1 to 3 carbon atoms, in the formula (D-2), ^{D 2} represents an alkyl group having 1 to 3 carbon atoms, the formula (D -3) in, ^{D 3} is an alkyl group having 1 to 4 carbon atoms.

  These may be used alone or in combination. Furthermore, even if it is a solvent which does not dissolve polyamic acid by itself, it may be mixed with the said solvent in the range which the produced | generated polyamic acid does not precipitate. Further, water in the organic solvent inhibits the polymerization reaction and causes hydrolysis of the generated polyamic acid. Therefore, it is preferable to use the organic solvent which has been dehydrated and dried 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 tetracarboxylic dianhydride is dispersed as it is or in an organic solvent. Alternatively, a method of dissolving and adding, a method of adding diamine to a solution in which tetracarboxylic dianhydride is dispersed or dissolved in an organic solvent, tetracarboxylic dianhydride and diamine alternately in organic solvent or simultaneously The method etc. which are added are mentioned and any of these methods may be used.

  Although the temperature at the time of the synthesis of the polyamic acid can be selected any temperature from -20 ° C to 150 ° C, it is preferably in the range of -5 ° C to 100 ° C, more preferably 0 ° C to 80 ° C. .

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

  The reaction can be carried out at any concentration, but when the concentrations of the diamine component and tetracarboxylic dianhydride as raw materials are too low, it becomes difficult to obtain a polymer of high molecular weight, and when the concentration is too high, the reaction liquid The viscosity is too high to make uniform stirring difficult, so it is preferably 1% by mass to 50% by mass, more preferably 5% by mass to 20% by mass. The initial stage of the reaction is performed at a high concentration, and thereafter, an organic solvent may be added.

  In the synthesis reaction of the polyamic acid, 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. As in the conventional polycondensation reaction, the closer the molar ratio is to 1.0, the higher the molecular weight of the formed polyamic acid.

  The polyamic acid obtained as described above can be recovered by precipitating a polymer by pouring the reaction solution into a poor solvent while well stirring it. Further, precipitation is carried out several times, and after washing with a poor solvent, the powder of purified polyamic acid can be obtained by normal temperature or heat drying.

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

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

[1] When Produced from Polyamic Acid A 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 It can be manufactured by

  As the esterifying agent, those which can be easily removed by purification are preferable, 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 can be mentioned. The addition amount of the esterifying agent is preferably 2 molar equivalents to 6 molar equivalents with respect to 1 mol of the repeating unit of the polyamic acid.

  As the organic solvent, for example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide or 1,3-dimethyl- And imidazolidinone. In addition, 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 formula (D-1) to the above formula (D- The solvent shown by 3) can be used.

  The solvents may be used alone or in combination. Furthermore, even if it is a solvent which does not dissolve a polyimide precursor, it may be used by mixing with the above-mentioned solvent in the range which the generated polyimide precursor does not precipitate. Further, since water in the solvent inhibits the polymerization reaction and causes hydrolysis of the produced polyimide precursor, it is preferable to use the solvent which has been dehydrated and dried.

  The solvent used for the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the viewpoint of polymer solubility, and one or more of these may be used in combination It is also good. The 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 precipitation of a polymer hardly occurs and a polymer can be easily obtained.

[2] When manufactured by reaction of tetracarboxylic acid diester dichloride and diamine Polyamic acid ester can be manufactured from the diamine component containing tetracarboxylic acid diester dichloride and the diamine of this invention.

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

  As a base, although a pyridine, a triethylamine, 4-dimethylaminopyridine etc. can be used, a pyridine is preferable in order for reaction to advance mildly. The amount of the base added is preferably 2 to 4 moles, more preferably 2 to 4 moles, per mole of the tetracarboxylic acid diester dichloride, from the viewpoint of easy removal and high molecular weight. Three-fold molar is more preferred.

  The solvent used for the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone from the viewpoint of the solubility of monomers and polymers, and these may be used alone or in combination of two or more. .

  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 precipitation of the polymer hardly occurs and a polymer can be easily obtained.

  Further, in order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for producing the 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] Production from Tetracarboxylic Acid Diester and Diamine A polyamic acid ester can be produced by polycondensation of a diamine component containing the tetracarboxylic acid diester and the diamine of the present invention.

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

  As a condensing agent, triphenyl phosphite, dicyclohexyl carbodiimide, 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, diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate and the like can be used. The amount of addition of the condensing agent is preferably 2 to 3 moles and more preferably 2 to 2.5 moles with respect to the tetracarboxylic acid diester.

  As a base, tertiary amines such as pyridine and triethylamine can be used. The amount of the base added is preferably 2 to 4 moles, more preferably 2.5 to 3.5 moles, per mole of the diamine component, from the viewpoint of easy removal and high molecular weight. Is more preferred.

  In the above reaction, the reaction proceeds efficiently by adding a 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 times mol to 1.0 times mol, and more preferably 0 times mol to 0.7 times mol with respect to the diamine component.

  Among the three methods for producing the polyamic acid ester, the polyamic acid ester having a high molecular weight can be obtained, so the production method of the above [1] or the above [2] is particularly preferable.

  The solution of the polyamic acid ester obtained as described above can precipitate the polymer by pouring it into a poor solvent while stirring well. Precipitation is carried out several times, and after washing with a poor solvent, the powder of purified polyamic acid ester can be obtained by normal temperature or heat drying. The poor solvent is not particularly limited, and water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene and the like can be mentioned.

<Method for producing polyimide>
The polyimide used in the present invention can be produced by imidizing the polyimide precursor.

  In the polyimide of the present invention, the ring closure ratio (imidization ratio) of the amic acid group or the amic acid ester group does not necessarily have to be 100%, and may be arbitrarily adjusted according to the application and purpose.

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

  In the case of thermally imidizing the polyimide precursor, the solution of the polyimide precursor is heated to 100 ° C. to 400 ° C., preferably 120 ° C. to 250 ° C., while removing water or alcohol generated by the imidization reaction out of the system It is preferable to do it.

  Catalytic imidization of a polyimide precursor can be performed by adding a basic catalyst and an acid anhydride to a solution of polyamic acid 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 moles, preferably 2 to 20 moles, of the amic acid group, and the amount of the acid anhydride is 1 to 50 moles of the amic acid group. Preferably, it is 3 molar times to 30 molar times.

  The basic catalyst may, for example, be pyridine, triethylamine, trimethylamine, tributylamine or trioctylamine. Among them, pyridine is preferable because it has an appropriate basicity to allow the reaction to proceed.

  As the acid anhydride, acetic anhydride, trimellitic anhydride, pyromellitic anhydride and the like can be mentioned. Among them, use of acetic anhydride is preferable because purification after completion of the reaction becomes easy. The imidation ratio 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 reaction solution of polyimide, 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, water and the like. The polymer precipitated by being put into a poor solvent and precipitated is preferably recovered by filtration and then dried by heating at normal temperature or under normal pressure or reduced pressure.

<Liquid crystal alignment agent>
The liquid crystal aligning agent is a coating liquid for producing a liquid crystal alignment 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. . The liquid crystal aligning agent of the present invention uses, as a resin component, at least one polymer selected from the group consisting of the above-described polyimide precursor and the polyimide obtained by ring-closing the polyimide precursor.

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

  All of the resin components in the liquid crystal aligning agent may be the polymer of the present invention, and polymers other than the polymer of the present invention may be mixed. Examples of such other polymers include polyimide precursors or polyimides obtained 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 dissolves uniformly. Specific examples thereof include N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethylsulfoxide, dimethylsulfone, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, 3-methoxy-N, N-dimethylpropanamide and the like can be mentioned. These may be used alone or in combination of two or more. Moreover, even if it is a solvent which can not melt | dissolve a polymer component uniformly by itself, as long as a polymer does not precipitate, you may mix with said organic solvent.

  The liquid crystal aligning agent may contain, in addition to the organic solvent for dissolving the polymer component, a solvent for improving the coating uniformity when the liquid crystal aligning agent is applied to the substrate. As such solvent, a solvent having lower surface tension than the above 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, 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, diethylene 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- (2-) Ethoxypropoxy) propanol, lactic acid methyl ester, lactic acid ethyl ester, lactic acid n-propyl ester, lactic acid n-butyl ester, lactic acid isoamyl ester and the like can be mentioned. These solvents may be used in combination of two or more.

  The said solvent turns into a poor solvent in which the solubility of resin is low. It is preferable that these solvents are 5 mass%-60 mass% of the organic solvent contained in a liquid-crystal aligning agent, More preferably, they are 10 mass%-50 mass%.

  In addition to the above, in the liquid crystal aligning agent, the polymer other than the polymer of the present invention, and for the purpose of changing the electric properties such as the dielectric constant and the conductivity of the liquid crystal alignment film, as long as the effects of the present invention are not impaired. Dielectrics or conductive substances, silane coupling agents for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate, crosslinking compounds for the purpose of enhancing the hardness and density of the film in the liquid crystal alignment film, When baking a coating film, you may add the imidation promoter etc. for the purpose of advancing the imidation of a polyimide precursor 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 parts by mass.

<Method of manufacturing liquid crystal alignment film>
A liquid crystal aligning film is a film | membrane obtained by apply | coating the said liquid crystal aligning agent to a board | substrate, drying, and baking.

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

  In the reflection type liquid crystal display device, an opaque material such as a silicon wafer can be used as long as it is used only on one side of the substrate. In this case, a material that reflects light such as aluminum can also be used as an electrode.

  As a coating method of a liquid crystal aligning agent, a spin coat method, a printing method, an inkjet method etc. are mentioned. In addition, as a method of using a coating liquid, dip, a roll coater, a slit coater, a spinner etc. exist, and you may use these according to the objective.

  The drying and baking steps after the application of the liquid crystal aligning agent can be performed at any temperature and time. Usually, in order to sufficiently remove the contained organic solvent, it is dried 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 Baking 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 coated film after firing is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may be reduced, so it is 5 nm to 300 nm, preferably 10 nm to 200 nm.

  As a method of carrying out the alignment process of the obtained liquid crystal aligning film, the rubbing method, the photo alignment treatment method, etc. are mentioned. For rubbing treatment, rayon cloth, nylon cloth, cotton cloth or the like can be used. Since it is difficult to obtain a uniform alignment state by rubbing treatment, the liquid crystal alignment film for vertical alignment can be used without rubbing when used as a liquid crystal alignment agent for vertical alignment.

  As a specific example of the light alignment treatment method, the coating film surface is irradiated with radiation deflected in a certain direction, and in some cases, heat treatment is further performed at a temperature of 150 ° C. to 250 ° C. to impart liquid crystal alignment ability. The method is mentioned. As radiation, ultraviolet light and visible light 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.

  Moreover, in order to improve liquid crystal orientation, you may irradiate a radiation, heating a coating film board | substrate at 50 degreeC-250 degreeC.

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.

  Above, the film irradiated with polarized radiation may then be contact treated with a solvent comprising at least one selected from water and an organic solvent.

  It will not specifically limit, if it is a solvent which melt | dissolves the decomposition product produced | generated by light irradiation as a solvent used for contact processing. As specific examples, 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- Methyl methoxy propionate, ethyl 3-ethoxy propionate, propyl acetate, butyl acetate, cyclohexyl acetate etc. are mentioned. These solvents may be used in combination of two or more.

  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. Particular preference is given to 1-methoxy-2-propanol or ethyl lactate.

  In the present invention, the contact treatment between the film irradiated with polarized radiation and the solution containing the organic solvent is carried out by a treatment such as immersion treatment, spray treatment, etc., in which the film and the solution are sufficiently in contact. Is preferred. Among them, a method of immersing the membrane in a solution containing an organic solvent, preferably for 10 seconds to 1 hour, more preferably for 1 minute to 30 minutes is preferable. The contact treatment may be performed at normal temperature or may be heated, but is preferably performed at 10 ° C. to 80 ° C., more preferably at 20 ° C. to 50 ° C. Also, if necessary, means for enhancing the contact with ultrasonic waves can be provided.

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

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

  As temperature of heating, 150 ° C-300 ° C is preferred. A higher temperature promotes reorientation of molecular chains, but too high a temperature may involve decomposition of molecular chains. Therefore, as heating temperature, 180 degreeC-250 degreeC are more preferable, and 200 degreeC-230 degreeC are especially preferable.

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

<Liquid crystal display element>
The liquid crystal display element is a liquid crystal display element produced by using 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 according to the present invention. .

  As an example of a method of manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure is described as an example. It may be a liquid crystal display element of an active matrix structure in which switching elements such as TFTs (Thin Film Transistors) are provided in respective pixel parts constituting an image display.

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, for example, ITO electrodes and are patterned to provide a desired image display. Then, 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 superimposed on one substrate so that the alignment film surfaces face each other, and the periphery is bonded with a sealing material. Usually, spacers are mixed in the sealing material in order to control the substrate gap. Moreover, it is preferable to scatter spacers for controlling the substrate gap also in the in-plane part where the sealing material is not provided. In part of the sealing material, an opening capable of being filled with liquid crystal from the outside is provided.

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

  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 residual image characteristics are excellent if the liquid crystal alignment film of the present invention is used.

  Next, the polarizing plate is installed. Specifically, a pair of polarizing plates is attached to the surface of the two substrates opposite to the liquid crystal layer. The liquid crystal display element of the present invention can be obtained through the above steps. Since this liquid crystal display device uses the liquid crystal alignment film obtained by the method for manufacturing a liquid crystal alignment film of the present invention as a liquid crystal alignment film, it has excellent residual image characteristics, and a high-definition multi-function mobile phone (Smart phone), tablet type personal computer, liquid crystal television etc.

The present invention will be more specifically described by way of the following examples. However, the present invention is not construed as being limited to these examples. Abbreviations of compounds used hereinafter and methods of measuring each property are as follows.
<Abbreviation of compound>
In the following formula DA-5 and the following 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 volume of 1.1 mL, corn rotor TE-1 (1 ° 34 ', R24), temperature 25 Measured in ° C.

<Production of Liquid Crystal Display Element>
First, a substrate with an electrode was prepared. The substrate is a glass substrate of 30 mm × 35 mm in size and 0.7 mm in thickness. On the substrate, an IZO electrode having a solid pattern is formed, which constitutes a counter electrode as a first layer. A SiN (silicon nitride) film formed by the CVD method is formed as a second layer on the first counter electrode. The film thickness of the second SiN film is 500 nm and functions as an interlayer insulating film. A comb-like pixel electrode formed by patterning an IZO film as a third layer is disposed on the second layer SiN film, and two pixels of a first pixel and a second pixel are formed. ing. The size of each pixel is about 10 mm in height and about 5 mm in width. At this time, the first opposing electrode and the third pixel electrode are electrically insulated by the action of the second SiN film.

  The pixel electrode of the third layer has a comb-like shape configured by arranging a plurality of V-shaped electrode elements 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 configured by arranging a plurality of bent V-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 resembling a bold, bold letter. And each pixel is divided up and down bordering on the central bending part, and has the 1st field of the upper part of a bending part, and the 2nd field of the lower side.

  When the first region and the second region of each pixel are compared, the forming directions of the electrode elements of the pixel electrodes constituting them are different. That is, on the basis of the rubbing direction of the liquid crystal alignment film described later, the electrode element of the pixel electrode is formed at 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 electrodes are formed at an angle of -10 ° (clockwise). That is, in the first area and the second area of each pixel, the directions of rotational movement (in-plane switching) in the plane of the substrate of the liquid crystal induced by voltage application between the pixel electrode and the counter electrode are mutually different. It is configured to be in the opposite direction.

  Next, after filtering the obtained liquid crystal aligning agent with a filter of 1.0 μm, an ITO film is formed on the back surface as the prepared substrate with electrode and the opposite substrate, and a columnar spacer having a height of 4 μm. Were spin-coated on each of the glass substrates having. Next, after drying for 5 minutes on a hot plate at 80 ° C., the film was baked at 230 ° C. for 20 minutes to obtain a polyimide film on each substrate as a coating film of 60 nm in film thickness. This polyimide film is rubbed with a rayon cloth (roll diameter 120 mm, rotation speed 500 rpm, moving speed 30 mm / sec, pushing amount 0.3 mm) in a predetermined rubbing direction, and then ultrasonic irradiation 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, combine them so that the rubbing directions are antiparallel, seal the periphery with the liquid crystal injection port left, and use an empty cell with a cell gap of 3.8 μm. Made. Liquid crystal (MLC-2041, manufactured by Merck & Co., Ltd.) was vacuum injected into this empty cell at normal temperature, and then the inlet was sealed to obtain a liquid crystal cell of anti-parallel alignment. 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, allowed to stand overnight, and used for each evaluation.

<Evaluation of relaxation characteristics of accumulated charge>
The afterimage was evaluated using the following optical system and the like. The manufactured liquid crystal cell is placed between two polarizing plates disposed 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 of frequency 30 Hz to this liquid crystal cell, and an AC voltage at which the relative transmittance was 23% was calculated as a drive voltage.

  In the residual image evaluation, while applying a 30 Hz AC voltage with a relative transmittance of 23% to drive the liquid crystal cell, a DC voltage of 1 V was applied at the same time to drive for 40 minutes. Thereafter, the applied DC voltage value was set to 0 V, only the application of the DC voltage was stopped, and in this state, driving was continued for another 15 minutes.

  The evaluation was performed by defining as “good” when relative transmittance decreased to 25% or less until 45 minutes passed from the time when the application of the DC voltage was started. When 45 minutes or more was required for the relative transmittance to decrease to 25% or less, it was defined as "poor" and evaluated.

  And the residual image evaluation according to the method mentioned above was performed on the temperature conditions of the state whose temperature of a liquid crystal cell is 23 degreeC.

<Evaluation of stability of liquid crystal alignment>
Using this liquid crystal cell, an alternating voltage of 10 VPP was applied at a frequency of 30 Hz for 168 hours in a constant temperature environment of 60.degree. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited, and left at room temperature for a day.

  After standing, the liquid crystal cell is placed between two polarizing plates disposed so that the polarization axes are orthogonal to each other, and the backlight is turned on with no voltage applied to minimize the brightness of transmitted light. The arrangement angle of the liquid crystal cell was adjusted. Then, the rotation angle when the liquid crystal cell is rotated from the angle at which the second region of the first pixel is the darkest to the angle at which the first region is the dark is calculated as the angle Δ. Similarly, in the second pixel, the second area and the first area were compared, and the 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 exceeds 0.1 degree, it was defined and evaluated as “defect”. When the value of the angle Δ of the liquid crystal cell did not exceed 0.1 degree, it was defined and evaluated as “good”.

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

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

<Evaluation of rubbing resistance>
The liquid crystal aligning agent was applied to an ITO substrate and temporarily dried, followed by firing in an IR oven at 230 ° C. to obtain a substrate with a liquid crystal alignment film. The liquid crystal alignment film was rubbed with a rayon cloth (roller rotational speed: 1000 rpm, stage moving speed: 20 mm / sec, indentation length: 0.4 mm). The substrate was observed with a microscope, and those which did not show rubbing streaks on the film surface were regarded as “good”, and those where streaks were seen were evaluated as “defect”.

<Composition example>
Synthesis Example 1
In a 500 mL flask equipped with a stirrer and a nitrogen inlet tube, 34.36 g (0.12 mol) of DA-3 was charged, and then 335.12 g of NMP was added and stirred for dissolution. While stirring this solution under water cooling, 22.77 g (0.10 mol) of CA-1 is added, 83.80 g of NMP is further added, and stirring is carried out at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-1) Obtained.

(Composition example 2)
After 25.20 g (0.088 mol) of DA-3 and 8.77 g (0.022 mol) of DA-6 were charged into a 500 mL flask equipped with a stirrer and a nitrogen inlet tube, 333.97 g of NMP was added and stirred. It was dissolved. While stirring this solution under water cooling, 22.96 g (0.11 mol) of CA-1 was added, and 326 g of NMP was further added, followed by stirring at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-2) .

(Composition example 3)
After 25.20 g (0.088 mol) of DA-3 and 8.72 g (0.022 mol) of DA-5 were charged into a 500 mL flask equipped with a stirrer and a nitrogen inlet tube, 334.28 g of NMP was added and stirred. It was dissolved. While stirring this solution under water cooling, 23.06 g (0.11 mol) of CA-1 is added, 83.57 g of NMP is further added, and stirring is carried out at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-3) Obtained.

(Composition example 4)
19.13 g (0.096 mol) of DA-4 is charged into a 500 mL flask equipped with a stirrer and a nitrogen inlet tube, then 232.72 g of a solvent (NMP: GBL = 50 wt%: 50 wt%) is added and dissolved by stirring I did. While stirring this solution under water cooling, 14.12 g (0.072 mol) of CA-2 is added, and 84.63 g of solvent (NMP: GBL = 50 wt%: 50 wt%) is further added, and then stirred for 2 hours The Thereafter, 4.76 g (0.024 mol) of DA-1 was added, 42.31 g of NMP was added, and the mixture was stirred and dissolved. While stirring again under water cooling, 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, polyamic acid solution (PAA- I got 4).

(Composition example 5)
23.59 g (0.12 mol) of DA-4 and 5.95 g (0.03 mol) of DA-1 were charged into a 500 mL flask equipped with a stirrer and a nitrogen inlet tube, and then 255.76 g of NMP was added and stirred. It was dissolved. While the solution was stirred 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
23.23 g (0.12 mol) of DA-4 and 4.56 g (0.03 mol) of DA-2 were charged into a 500 mL flask equipped with a stirrer and a nitrogen inlet tube, and then 241.76 g of NMP was added and stirred. It was dissolved. While stirring this solution under water cooling, 13.71 g (0.070 mol) of CA-2 was added, and after adding 69.07 g of NMP, the mixture was allowed to stir 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
28.69 g (0.144 mol) of DA-4 and 7.14 g (0.036 mol) of DA-1 were added to a 500 mL flask equipped with a stirrer and a nitrogen inlet tube, and then 296.56 g of NMP was added and stirred. It was dissolved. While stirring this solution under water cooling, 16.41 g (0.084 mol) of CA-2 was added, and after 84.73 g of NMP was further added, the mixture was stirred for 2 hours. Thereafter, 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
18.98 g (0.048 mol) of DA-5 and 14.28 g (0.048 mol) of DA-7 were added to a 500 mL flask equipped with a stirrer and a nitrogen inlet tube, and then 312.67 g of NMP was added and stirred. It was dissolved. While stirring this solution under water cooling, add 20.04 g (0.092 mol) of CA-1 and then 78.17 g of NMP, and then stir at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-8). Got).

Synthesis Example 9
After putting 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 inlet tube, add 289.28 g of NMP and stir It was dissolved. While stirring this solution under water cooling, 27.94 g (0.14 mol) of CA-2 is added, and 72.32 g of NMP is further added, followed by stirring for 2 hours to obtain a polyamic acid solution (PAA-9). The

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

(Comparative example 2)
1.33 g of PAA-1 and 4.27 g of PAA-5 in a 20 ml sample tube containing a stirrer, 4.40 g of NMP, 5.36 g of GBL, 4.00 g of BCS, 1 of AD-1 0.64g of GBL solutions containing weight% were added, and it stirred for 30 minutes with a magnetic stirrer, and obtained the liquid crystal aligning agent (A-2).

(Comparative example 3)
1.33 g of PAA-2 and 4.27 g of PAA-6 in a 20-ml sample tube containing a stirrer, 4.40 g of NMP, 5.36 g of GBL, 4.00 g of BCS, and 1 of AD-2 0.64g of GBL solutions containing weight% were added, and it stirred for 30 minutes with a magnetic stirrer, and obtained liquid crystal aligning agent (A-3).

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

Example 1
1.33 g of PAA-3 and 4.27 g of PAA-6 in a 20 ml sample tube containing a stirrer, 4.40 g of NMP, 5.36 g of GBL, 4.00 g of BCS, 1 of AD-2 0.64g of GBL solutions containing weight% were added, and it stirred for 30 minutes with a magnetic stirrer, and obtained liquid crystal aligning agent (B-1).

(Example 2)
1.33 g of PAA-3 and 4.27 g of PAA-6 in a 20 ml sample tube containing a stirrer, 4.16 g of NMP, 5.36 g of GBL, 4.00 g of BCS, 1 of AD-2 0.64 g of a GBL solution containing% 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-2).

(Example 3)
1.33 g of PAA-3 and 4.27 g of PAA-7 in a 20 ml sample tube containing a stirrer, 4.40 g of NMP, 5.36 g of GBL, 4.00 g of BCS, 1 of AD-2 0.64g of GBL solutions containing weight% were added, and it stirred for 30 minutes with a magnetic stirrer, and obtained liquid crystal aligning agent (B-3).

(Example 4)
1.33 g of PAA-3 and 4.27 g of PAA-7 in a 20-ml sample tube containing a stirrer, 4.16 g of NMP, 5.36 g of GBL, 4.00 g of BCS, and 1 of AD-2 0.64 g of GBL solution containing% by weight and 0.24 g of 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 mentioned above, the liquid crystal aligning film of this invention showed a favorable result in any of rubbing tolerance, BL tolerance evaluation, stability evaluation of liquid crystal alignment, and evaluation of afterimage disappearance time.

Claims (8)

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 the following formula (1) and 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 consisting of azetidine, pyrrolidine, piperidine or hexamethyleneimine R ₂ and R ₃ are each independently a monovalent organic group, and q and r are each a divalent group representing a hetero ring, and a substituent may be bonded to these ring portions. Independently, it is 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-mentioned 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 an alkyl group having 1 to 3 carbon hydrogen or C, ^{"* 3"} represents a bond to the carbon atom ^{to which R 2} and ^{R 3} are attached.) represents the , “* ¹ ” and “* ² ” indicate that they are bonds with other atoms.) The liquid crystal aligning agent of Claim 1 to 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 C1-C5 linear alkylene.)   The liquid crystal aligning agent of Claim 1 or Claim 2 whose content rate of the diamine represented by said Formula (1) is 1 mol%-80 mol% with respect to 1 mol of all the diamine components. The liquid crystal aligning agent of any one of Claim 1 to 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 Claim 1 to 4 which contains the polyimide precursor containing the structural unit of following formula (5) as (C) component.

(In the 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 Z ₁ and Z ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkenyl group having 2 to 10 carbon atoms, or a carbon number 2-10 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.

  The liquid crystal aligning film obtained from the liquid crystal aligning agent of any one of Claims 1-6.   The liquid crystal display element which comprises the liquid crystal aligning film of Claim 7.