KR102118762B1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

Provided is a liquid crystal aligning agent that forms a preferred liquid crystal aligning film in a liquid crystal display device having excellent display quality.
The liquid crystal aligning agent contains at least one polymer selected from the group consisting of a polyimide precursor having a metabenzyl type side chain structure and a side chain structure containing a photoreactive group, and a polyimide obtained by imidizing the polyimide precursor. Is prepared. The polyimide precursor is formed by performing a copolymerization reaction with tetracarboxylic dianhydride 2 anhydride using a diamine compound for realizing a metabenzyl type side chain structure and a diamine compound having a photoreactive group. Using the liquid crystal aligning agent, a vertical alignment type liquid crystal aligning film having light alignment properties is formed. A liquid crystal display element is manufactured using the liquid crystal aligning film.

Description

Liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element TECHNICAL FIELD LIQUID CRYSTAL ALIGNMENT AGENT, LIQUID CRYSTAL ALIGNMENT FILM, AND LIQUID CRYSTAL DISPLAY ELEMENT

The present invention relates to a liquid crystal aligning agent, a liquid crystal aligning film and a liquid crystal display element suitable for providing a liquid crystal display element of excellent display quality.

The liquid crystal display element is known as a lightweight, thin, and low power consumption display device, and has recently achieved remarkable development, such as used in large-sized television applications.

The liquid crystal display element is configured by encapsulating and sealing a liquid crystal layer between a pair of substrates, and aligning the liquid crystals of the liquid crystal layer in a predetermined direction between the substrates. In a liquid crystal display element, a liquid crystal responds by applying a voltage to an electrode formed on a pair of substrates, and a desired image can be displayed by using the change in alignment by the response of the liquid crystal.

This liquid crystal display device has various liquid crystal modes in which the initial alignment state of the liquid crystal molecules and the form of the alignment change due to voltage application are different. For example, as an initial alignment state of liquid crystal molecules, a TN (Twisted Nematic) mode in which a liquid crystal has a 90° twist alignment between a pair of substrates is known.

Recently, among the display methods of the liquid crystal display element, a liquid crystal display element in a vertical alignment (VA) mode in which liquid crystal molecules having negative dielectric anisotropy are vertically aligned to a substrate has been actively developed (for example, For example, see Patent Documents 1 and 2).

In this VA mode liquid crystal display element, the liquid crystals vertically aligned by voltage application are inclined in a predetermined direction, and are aligned so as to be parallel to the substrate and to be directed in a predetermined direction. In addition, the VA mode can realize a high contrast ratio, a wide viewing angle, and additionally excellent response characteristics.

This VA type liquid crystal display element is an initial alignment state of the liquid crystal when no voltage is applied, in order to enable the operation of changing the alignment of the liquid crystal described above, wherein the liquid crystal is slightly inclined toward the predetermined direction in the plane from the normal direction of the substrate. It is required to form.

In the VA type liquid crystal display device, a multi-domain vertical alignment (MVA) method is known in which a projection structure is formed on a TFT substrate or a color filter substrate in order to control the inclination direction of the liquid crystal by applying a voltage.

In addition, a PVA (Patterned Vertical Alignment) method is known in which a slit structure is formed on an electrode made of ITO (Indiumtinoxide) or the like of a substrate sandwiching the liquid crystal layer, and the tilting direction of the liquid crystal is controlled by an inclined electric field.

Further, a liquid crystal alignment film is formed between the substrate and the liquid crystal layer, and this is subjected to a rubbing treatment to align the liquid crystal molecules by slightly inclining from the normal direction of the substrate toward one direction in the substrate plane, or the photo alignment method disclosed in Patent Documents 3, 4, etc. This is known.

For example, in patent document 3, the diamine compound which has a cinnamic acid ester structure in a molecule|numerator is used. Then, a polyamic acid that is a polyimide precursor composed of the diamine compound and tetracarboxylic dianhydride is synthesized, and polyimide is formed from the polyamic acid to obtain a vertically oriented liquid crystal alignment film of photoalignability. Polyimide is a high heat-resistant polymer material, has high reliability, and is a preferred material for use in liquid crystal alignment films.

The above-described VA mode liquid crystal display device has the above-described excellent characteristics, and is intended to be used for large-sized televisions, high-definition (high-definition), high-definition mobile applications (digital cameras or mobile phone display units), and the like.

International Publication No. 2008/117615 Brochure Japanese Patent Application Publication No. 2008-76950 Japanese Publication Patent Publication No. 2009-520702 Japanese Patent Application Publication No. 2011-100099

VA mode liquid crystal display devices are required to further improve display quality in accordance with the expansion of applications to large-sized TVs, high-definition mobile devices, and the like.

Further, as one of the tasks for improving the display quality, there is a demand for improvement in display defects called burn-in.

Burn-in in a liquid crystal display element is one of display defects in which the previous display is displayed like a shadow when the display is switched after displaying the same image continuously for a long time. The display defect caused by such burn-in causes a decrease in display quality of the liquid crystal display element.

Although display defects due to burn-in differ in the severity of the degree of occurrence, there is a concern that it may occur in a liquid crystal display element in any mode. However, in a VA mode liquid crystal display element that is used in many applications in which high display quality is particularly required, the improvement is strongly demanded.

An object of the present invention is to provide a liquid crystal aligning agent capable of forming a liquid crystal aligning film suitable for providing a liquid crystal display element having excellent display quality, a liquid crystal aligning film suitable for providing a liquid crystal display element having excellent display quality, and a liquid crystal display element having excellent display quality. Is to provide.

This invention makes the following structures a summary.

(1) containing at least one polymer selected from the group consisting of a polyimide precursor having a metabenzyl type side chain structure and a side chain structure containing a photoreactive group, and a polyimide obtained by imidizing the polyimide precursor. Liquid crystal aligning agent, characterized in that.

(2) The polyimide precursor is a polyamic acid obtained by reacting a first diamine compound represented by the following formula (1), a diamine component containing the second diamine compound having the photoreactive group, and tetracarboxylic dianhydride. The liquid crystal aligning agent as described in said (1).

delete

(X ¹ is a hydrocarbon group having 8 to 22 carbon atoms or a group represented by the following formula (1A))

delete

(Y ¹ is a single bond, -(CH ₂ ) _a- (a is an integer from 1 to 15), -O-, -CH ₂ O-, -COO- or OCO-. Y ² is a single bond or- (CH ₂ ) _b- (b is an integer from 1 to 15) Y ³ is a single bond, -(CH ₂ ) _c- (c is an integer from 1 to 15), -O-, -CH ₂ O -, -COO- or -OCO- Y ⁴ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a hetero ring (any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, a carbon number) Selected from the group consisting of 1 to 3 alkoxy groups, 1 to 3 fluorine-containing alkyl groups, 1 to 3 fluorine-containing alkoxy groups or fluorine atoms), or an organic group having 12 to 25 carbon atoms having a steroid skeleton Y ⁵ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring, and a heterocycle (any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, an alkyl group having 1 to 3 carbon atoms) An alkoxy group, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom) Y ⁶ is an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, It is a C1-C18 alkoxy group or a C1-C18 fluorine-containing alkoxy group, n is an integer of 0-4.)

(3) The liquid crystal aligning agent according to the above (2), wherein the photoreactive group of the second diamine compound is a group that causes either a photodimerization reaction or a photoisomerization reaction.

(4) The liquid crystal aligning agent according to (2) or (3) above, wherein the photoreactive group of the second diamine compound has at least one structure selected from the group consisting of cinnamoyl structure, coumarin structure and chalcone structure.

(5) The liquid crystal aligning agent according to any one of (2) to (4), wherein the photoreactive group of the second diamine compound includes a structure represented by any one of the following formulas (2A) and (2B).

delete

delete

(In the formula (2A) and the formula (2B), R is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (however, any arbitrary hydrogen atom may be substituted with a fluorine atom), or a number of carbon atoms 1 to Represents an alkoxy group of 10 (however, any hydrogen atom may be substituted with a fluorine atom) A and B each independently represent a single bond or any ring structure represented by the following formula. Any hydrogen atom may be substituted with an alkoxy group having 1 to 10 carbon atoms T ¹ to T ⁴ each independently represent a single bond, ether, ester, amide or ketone bond, S is a single bond or the number of carbon atoms The alkylene group of 1-10 is shown.)

delete

(6) In the above (2) to (5), the content of the metabenzyl type diamine compound contained in the diamine component is 5 mol% to 50 mol%, and the content of the second diamine compound is 20 mol% to 95 mol%. The liquid crystal aligning agent in any one.

(7) The liquid crystal aligning agent according to any one of (1) to (6), wherein the content of the polymer is 1 to 20 mass%.

(8) The liquid crystal aligning agent according to any one of (1) to (7) above, further comprising a crosslinking agent.

(9) The liquid crystal aligning film obtained using the liquid crystal aligning agent in any one of said (1)-(8).

(10) The liquid crystal display element which has the liquid crystal aligning film as described in said (9).

ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal aligning agent which can form the liquid crystal aligning film suitable for providing the liquid crystal display element of excellent display quality, the liquid crystal aligning film suitable for providing liquid crystal display element of excellent display quality, and the liquid crystal display element of excellent display quality are provided. Can provide.

1 is a graph showing comparison of evaluation results of a liquid crystal cell of an example of the present invention.

The inventor studied the burn-in problem of the VA mode liquid crystal display element, and found that it is the main factor that fluctuations in the pretilt angle of the liquid crystal of the liquid crystal layer, which occur when the AC voltage is continuously applied.

Normally, the pretilt angle of the liquid crystal of the liquid crystal layer sandwiched between the pair of substrates is constant, and it is required that the variation is small even by driving the liquid crystal. In the VA mode liquid crystal display element, as described above, the pretilt angle of the liquid crystal is formed by, for example, a liquid crystal alignment film subjected to alignment treatment. At this time, in the VA mode liquid crystal display element, a change in the pretilt angle formed between the liquid crystal alignment film and the liquid crystal may occur due to driving of the liquid crystal by application of an alternating voltage for a long time.

In that case, when the application of the alternating voltage for a long time is made in some areas in the plane of the liquid crystal display element, fluctuation of the pretilt angle occurs only in that area. On the other hand, in the region where the application of the alternating voltage is not performed, such pretilt angle fluctuation does not occur, and the initial state is maintained. As a result, a change may occur in the driving characteristics of the liquid crystal between these regions. Then, a change in the driving characteristics of the liquid crystal in some such regions may be recognized as burn-in of the VA mode liquid crystal display.

As a result of further examination, the present inventors have found that it is effective for improving the burn-in described above by specifying the structure of the liquid crystal alignment film used in the VA mode liquid crystal display device, and have completed the present invention.

The VA mode liquid crystal display element can be configured by using a liquid crystal alignment film as described above. And, as the liquid crystal aligning film, a vertical alignment type liquid crystal aligning film of photoalignability can be used. It is unnecessary to form an additional structure such as a slit structure on the electrode of the vertical alignment type liquid crystal alignment film of the photo-alignment property. Moreover, the photo-alignment process of a liquid crystal aligning film is possible, and the previously known rubbing process can be made unnecessary.

Rubbing treatment, which is one of the orientation treatment methods, is an orientation treatment method in which the surface of the polyimide film is rubbed in a predetermined direction using a cloth. In addition to generating dust by rubbing an organic film such as a polyimide film constituting the liquid crystal aligning film, this rubbing treatment may cause scratches on the surface of the liquid crystal aligning film to cause unevenness in liquid crystal alignment. Therefore, in the liquid crystal aligning film, it is preferable to adopt a photo alignment treatment in which rubbing treatment is unnecessary.

Thus, the present inventor applies the vertical alignment type liquid crystal alignment film technology of photo-alignment to the VA mode liquid crystal display device, and improves burn-in by applying an alternating voltage of the VA mode liquid crystal display device by the liquid crystal alignment film.

The vertical alignment type liquid crystal aligning film of the photo-alignment property of a VA mode liquid crystal display element is comprised from a polymer like a conventional liquid crystal aligning film. And it can form by apply|coating and film-forming using the liquid crystal aligning agent for forming the liquid crystal aligning film. In that case, a liquid crystal aligning agent is comprised as a component and contains the polymer suitable for formation of a liquid crystal aligning film. In the present invention, the polymer component of the liquid crystal aligning agent is formed by copolymerizing them using a component for realizing the vertical alignment of the liquid crystal and a photoreactive group for realizing the photo alignment treatment. And the liquid crystal aligning agent can provide the vertically-aligned liquid crystal display element of photo-alignment property suitable for a VA mode liquid crystal display element by including the formed polymer.

The present inventor also provides a vertical alignment liquid crystal alignment film with improved burn-in alignment by specifying a structure of a liquid crystal alignment film, specifically by specifying a structure of a polymer component contained in the liquid crystal alignment agent. More specifically, the structure of the component for realizing the vertical alignment of the liquid crystal is specified, and the structure of the component having a photoreactive group for realizing the photo alignment treatment is specified, and the structure of the polymer obtained thereby is specified. In this way, the liquid crystal aligning agent of this invention contains the polymer of the specific structure, and provides the vertical alignment type liquid crystal aligning film and liquid crystal display element of photo-alignment which burn-in by application of alternating current voltage was reduced.

<liquid crystal aligning agent>

The liquid crystal aligning agent of the present invention includes a polymer whose structure is specified, and the polymer is a polyimide precursor having a metabenzyl type side chain structure and a side chain structure including a photoreactive group enabling photoreaction treatment, and It is at least 1 type of polymer chosen from the group which consists of polyimide obtained by imidizing it. In the present invention, as the polyimide precursor, in addition to polyamic acid, polyamic acid ester and the like are included. In particular, polyamic acid which is easy to form polyimide is preferable.

The polyimide precursor contained in the liquid crystal aligning agent of the present invention and the polyimide obtained by imidizing the polyimide precursor, as described above, have a metabenzyl type side chain structure in the molecule and light that enables photoreaction treatment. It has a side chain structure containing a reactive group. The polyimide precursor can be synthesized by reacting a diamine component containing at least one diamine compound and a tetracarboxylic acid derivative component such as tetracarboxylic dianhydride according to a known method.

As a method for obtaining a polyimide precursor having the above-described structure, a diamine compound having a structure for realizing a metabenzyl type side chain structure in the molecule can be used as the first diamine compound in the diamine component used for the synthesis. have. As the second diamine compound, a diamine compound having a photoreactive group that enables photo-alignment treatment in the molecule can be used. Then, by using the first diamine compound and the second diamine compound for copolymerization reaction with a tetracarboxylic acid derivative component, a polyimide precursor having a desired structure in the present invention and imidizing it to obtain a polyimide You can.

Hereinafter, diamine components, such as the 1st and 2nd diamine compound mentioned above, are demonstrated. That is, a diamine compound (hereinafter, also referred to as a metabenzyl type diamine compound) having a structure for realizing a metabenzyl type side chain structure in a molecule, which is preferable for obtaining a polyimide precursor having the structure described above, and a molecule A diamine compound (hereinafter, also referred to as a photoreactive diamine compound) having a photoreactive group that enables photo alignment treatment in the inside will be described. Then, preferred tetracarboxylic acid derivatives will be described, and the polyimide precursor, polyimide, and the like in the present invention will be described as components formed by using them and contained in the liquid crystal aligning agent in the present invention. .

[Metabenzyl type diamine compound]

The metabenzyl type diamine compound in this invention is represented by following formula (1), for example. That is, the metabenzyl type diamine compound in the present invention has a benzene ring structure in which two amino groups are introduced at positions 1 and 3, and a benzyl group at position 5 of the benzene ring that becomes a meta position for each amino group. It is preferred that it is an introduced compound.

Since the metabenzyl type diamine compound in the present invention has a structure represented by the following formula (1), the liquid crystal aligning agent containing a polyimide precursor synthesized using this and at least one polymer of polyimide is vertically aligned. The liquid crystal aligning film of this invention can be formed. And the metabenzyl type diamine compound in this invention can be used together with the photoreactive diamine compound mentioned later in detail, and can form the polyimide precursor etc. of the desired structure mentioned above. The liquid crystal aligning agent of this invention containing this polyimide precursor etc. forms the liquid crystal aligning film of this invention which controls the magnitude of the pretilt angle of the liquid crystal of a liquid crystal display element, and also improves burn-in by application of alternating voltage. You can.

delete

In Formula (1), X ¹ is a hydrocarbon group having 8 to 22 carbon atoms or a group represented by the following Formula (1A).

delete

In formula (1A), Y ¹ is a single bond, -(CH ₂ ) _a- (a is an integer from 1 to 15), -O-, -CH ₂ O-, -COO- or OCO-. Y ² is a single bond or -(CH ₂ ) _b- (b is an integer from 1 to 15). Y ³ is a single bond, -(CH ₂ ) _c- (c is an integer from 1 to 15), -O-, -CH ₂ O-, -COO- or -OCO-. Y ⁴ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring, and a heterocycle (any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, 1 to 3 carbon atoms. It may be substituted with a fluorine-containing alkyl group, a fluorine-containing alkoxy group having 1 to 3 carbon atoms or a fluorine atom), or a divalent organic group selected from the group consisting of an organic group having 12 to 25 carbon atoms having a steroid skeleton. Y ⁵ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring, and a heterocycle (any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, 1 to 3 carbon atoms. It may be substituted with a fluorine-containing alkyl group, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom). Y ⁶ is a C1-C18 alkyl group, a C1-C18 fluorine-containing alkyl group, a C1-C18 alkoxy group, or a C1-C18 fluorine-containing alkoxy group. n is an integer of 0-4.

In the formula (1A), Y ¹ is a single bond, -(CH ₂ ) _a- (a is an integer from 1 to 15), -O-, -CH ₂ O-, -COO-, or -OCO- . Among them, a single bond, -(CH ₂ ) _a- (a is an integer from 1 to 15), -O-, -CH ₂ O-, or -COO- is a viewpoint to facilitate the synthesis of the diamine compound Is preferred. Moreover, single bond, -(CH ₂ ) _a- (a is an integer of 1 to 10), -O-, -CH ₂ O- or -COO- is more preferable.

In formula (1A), Y ² is a single bond or -(CH ₂ ) _b- (b is an integer from 1 to 15). Especially, a single bond or -(CH ₂ ) _b- (b is an integer of 1-10) is preferable.

In formula (1A), Y ³ is a single bond, -(CH ₂ ) _c- (c is an integer from 1 to 15), -O-, -CH ₂ O-, -COO- or -OCO-. Among them, single bond, -(CH ₂ ) _c- (c is an integer from 1 to 15), -O-, -CH ₂ O-, -COO- or -OCO- facilitates the synthesis of the diamine compound It is preferable from the viewpoint of making it. Moreover, single bond, -(CH ₂ ) _c- (c is an integer of 1 to 10), -O-, -CH ₂ O-, -COO- or -OCO- are more preferable.

In formula (1A), Y ⁴ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring, and a heterocycle (any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms) Group, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom), or an organic group having 12 to 25 carbon atoms having a steroid skeleton It is a divalent organic group. Especially, a C2-C25 divalent organic group which has a benzene ring, a cyclohexane ring, or a steroid skeleton is preferable.

In formula (1A), Y ⁵ is a cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring, and a heterocycle, and any hydrogen atom on these cyclic groups, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms It may be substituted with a group, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom.

In said formula (1A), n is an integer of 0-4. Preferably it is an integer of 0-2.

In formula (1A), Y ⁶ is a C1-C18 alkyl group, a C1-C18 fluorine-containing alkyl group, a C1-C18 alkoxy group, or a C1-C18 fluorine-containing alkoxy group. Especially, it is preferable that it is a C1-C18 alkyl group, a C1-C10 fluorine-containing alkyl group, a C1-C18 alkoxy group, or a C1-C10 fluorine-containing alkoxy group. More preferably, it is a C1-C12 alkyl group or a C1-C12 alkoxy group. More preferably, it is a C1-C9 alkyl group or a C1-C9 alkoxy group.

Next, specific examples of the diamine compound having the structure represented by the formula (1) are given, but the present invention is not limited to these examples.

delete

In the formulas [1A-1] to [1A-3], R ₃ is -CH ₂ OCO-, -CH ₂ O- or -CH ₂ -, and R ₄ is a straight or branched alkyl group having 1 to 18 carbon atoms. It is a C1-C18 linear or branched alkoxy group, a C1-C18 linear or branched fluorine-containing alkyl group, or a C1-C18 linear or branched fluorine-containing alkoxy group.

delete

In formula [1A-4] and formula [1A-5], R ₅ is -CH ₂ OCO-, -CH ₂ O- or CH ₂ -, and R ₆ is a linear or branched alkyl group having 1 to 18 carbon atoms. to be.)

delete

In the formulas [1A-6] and [1A-7], R ₈ is a straight or branched alkyl group having 3 to 12 carbon atoms, and the cis-trans isomers of 1,4-cyclohexylene are trans isomers, respectively.

delete

In the formula [1A-8], L ₄ is a straight or branched alkyl group having 3 to 20 carbon atoms which may be substituted with a fluorine atom, and L ₃ is a 1,4-cyclohexylene group or 1,4-phenylene group. , L ₂ is an oxygen atom or COO-* (however, a bonding hand with “*” bonds to A ₃ ), L ₁ is an oxygen atom or COO-* (however, a bonding hand with “*” attached ( CH ₂ )a ₂ )). Also, a ₁ is an integer of 0 or 1, a ₂ is an integer of 2 to 10, and a ₃ is an integer of 0 or 1)

delete

When the polymer is synthesized using the diamine component containing the metabenzyl type diamine compound, the preferred content of the metabenzyl type diamine compound contained in the diamine component is not particularly limited, but is 5 mol% to 50 mol% in the diamine component. Is preferable, More preferably, it is 5 mol%-30 mol%.

[Photo-reactive diamine compound]

The photoreactive diamine compound in the present invention has a photoreactive group. It is preferable that the photoreactive group of the photoreactive diamine compound in this invention is a group which produces either a photodimerization reaction or a photoisomerization reaction. By having such a photoreactive group, the liquid crystal aligning agent containing the polyimide precursor synthesized using the photoreactive diamine compound and at least one polymer of polyimide can form a liquid crystal alignment film capable of photo-alignment treatment. Then, it can be used together with the above-described metabenzyl type diamine compound to form a polymer having a desired structure such as a polyimide precursor, thereby forming a vertically oriented liquid crystal alignment film capable of photo-alignment treatment.

More specifically, it is preferable that the photoreactive diamine compound has at least one structure selected from the group consisting of a cinnamoyl structure, a coumarin structure, and a chalcone structure. By having a photoreactive group having such a structure, a liquid crystal aligning agent comprising a polyimide precursor synthesized using a photoreactive diamine compound and at least one polymer of polyimide enables high-efficiency photoalignment treatment, and high liquid crystal alignment A liquid crystal alignment film having control performance can be formed.

As for the photoreactive diamine compound in this invention, the compound represented by following formula (2) is preferable.

delete

In the formula (2), X ² represents a substituent, and is a group of a structure represented by the following formula (2A) or the following formula (2B).

delete

delete

In the formulas (2A) and (2B), R is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms (however, any arbitrary hydrogen atom may be substituted with a fluorine atom), or 1 to 18 carbon atoms. Represents an alkoxy group (however, any hydrogen atom may be substituted with a fluorine atom). A and B each independently represent a single bond or any ring structure represented by the following formula. However, any hydrogen atom in the ring structure may be substituted with an alkoxy group having 1 to 10 carbon atoms. T ¹ to T ⁴ each independently represent a single bond, ether, ester, amide or ketone bond. S represents a single bond or an alkylene group having 1 to 10 carbon atoms.

delete

Hereinafter, preferable examples of the photoreactive diamine compound are shown.

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

In addition, in the C _n H _{2n +1} portion of the diamine compound exemplified by the above formula, n represents an integer from 0 to 18.

And the following compounds are particularly preferable from the viewpoint of photoreactivity.

delete

In the C _n H _{2n +1} portion of the particularly preferred diamine compound exemplified above, n represents an integer from 0 to 18.

Moreover, in the diamine component suitable for formation of the polyimide precursor of the above-mentioned desired structure contained in the liquid crystal aligning agent of the present invention, in addition to the benzyl-type diamine compound and photoreactive diamine compound described above, other diamine compounds (others) It may also be called a diamine compound.). Other diamine compounds are not particularly limited, and examples thereof include alicyclic diamines, aromatic diamines, aromatic-aliphatic diamines, heterocyclic diamines, and aliphatic diamines. The specific example is as follows.

Examples of the alicyclic diamines are 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'. -Dimethyldicyclohexylamine, isophoronediamine, and the like.

Examples of aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1 ,4-diamino-2-methoxybenzene, 2,5-diamino-p-xylene, 1,3-diamino-4-chlorobenzene, 3,5-diamino benzoic acid, 1,4-diamino -2,5-dichlorobenzene, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-2,2'-dimethylbibenzyl, 4,4'-diaminodiphenyl Methane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 2,2'-diaminosteel Ben, 4,4'-diaminostilbene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfide, 4,4' -Diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminobenzophenone, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4- Aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 3,5-bis(4-aminophenoxy)benzoic acid, 4,4'-bis(4-aminophenoxy)bibenzyl, 2,2-bis[(4-aminophenoxy)methyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4-(4- Aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, 1,1-bis(4-aminophenyl)cyclo Hexane, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, 9,9-bis(4-aminophenyl)fluorene, 2,2-bis(3-aminophenyl)hexa Fluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenylamine, 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1 ,5-diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrene, 1,6-diaminopyrene, 1,8-diaminopyrene, 2,7-diaminofluorene, 1 ,3-bis(4-aminophenyl)tetramethyldisiloxane, benzidine, 2,2'-dimethylbenzidine, 1,2-bis(4-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane , 1,4-bis(4-aminophenyl)butane, 1 ,5-bis(4-aminophenyl)pentane, 1,6-bis(4-aminophenyl)hexane, 1,7-bis(4-aminophenyl)heptane, 1,8-bis(4-aminophenyl)octane , 1,9-bis(4-aminophenyl)nonane, 1,10-bis(4-aminophenyl)decane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-amino Phenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 1,7-bis(4-aminophenoxy)heptane, 1,8 -Bis(4-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, di(4-aminophenyl)propane-1, 3-dioate, di(4-aminophenyl)butane-1,4-dioate, di(4-aminophenyl)pentane-1,5-dioate, di(4-aminophenyl)hexane-1,6- Dioate, di(4-aminophenyl)heptane-1,7-dioate, di(4-aminophenyl)octane-1,8-dioate, di(4-aminophenyl)nonane-1,9-dioate , Di(4-aminophenyl)decane-1,10-dioate, 1,3-bis[4-(4-aminophenoxy)phenoxy]propane, 1,4-bis[4-(4-aminophenoxy City) phenoxy] butane, 1,5-bis [4-(4-aminophenoxy) phenoxy] pentane, 1,6-bis [4-(4-aminophenoxy) phenoxy] hexane, 1,7 -Bis[4-(4-aminophenoxy)phenoxy]heptane, 1,8-bis[4-(4-aminophenoxy)phenoxy]octane, 1,9-bis[4-(4-aminophenoxy) Poetry) phenoxy] nonane, 1,10-bis [4-(4-aminophenoxy) phenoxy] decane, and the like.

Examples of aromatic-aliphatic diamines are 3-aminobenzylamine, 4-aminobenzylamine, 3-amino-N-methylbenzylamine, 4-amino-N-methylbenzylamine, 3-aminophenethylamine, 4-amino Phenethylamine, 3-amino-N-methylphenethylamine, 4-amino-N-methylphenethylamine, 3-(3-aminopropyl)aniline, 4-(3-aminopropyl)aniline, 3-(3 -Methylaminopropyl)aniline, 4-(3-methylaminopropyl)aniline, 3-(4-aminobutyl)aniline, 4-(4-aminobutyl)aniline, 3-(4-methylaminobutyl)aniline, 4 -(4-methylaminobutyl)aniline, 3-(5-aminopentyl)aniline, 4-(5-aminopentyl)aniline, 3-(5-methylaminopentyl)aniline, 4-(5-methylaminopentyl) Aniline, 2-(6-aminonaphthyl)methylamine, 3-(6-aminonaphthyl)methylamine, 2-(6-aminonaphthyl)ethylamine, 3-(6-aminonaphthyl)ethylamine, etc. Can be heard.

Examples of heterocyclic diamines include 2,6-diaminopyridine, 2,4-diaminopyridine, 2,4-diamino-1,3,5-triazine, and 2,7-diaminodibenzofuran , 3,6-diaminocarbazole, 2,4-diamino-6-isopropyl-1,3,5-triazine, 2,5-bis(4-aminophenyl)-1,3,4-oxa Diazole and the like.

Examples of the aliphatic diamines include 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, and 1,7 -Diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,3-diamino-2,2-dimethylpropane, 1,6-diamino -2,5-dimethylhexane, 1,7-diamino-2,5-dimethylheptane, 1,7-diamino-4,4-dimethylheptane, 1,7-diamino-3-methylheptane, 1, And 9-diamino-5-methylheptane, 1,12-diaminododecane, 1,18-diaminooctadecane, and 1,2-bis(3-aminopropoxy)ethane.

<tetracarboxylic acid derivative>

The tetracarboxylic acid derivative used for the reaction with the diamine compound described above and capable of synthesizing the polyimide precursor or polyimide contained in the liquid crystal aligning agent of the present invention is not particularly limited. As a preferable tetracarboxylic-acid derivative, the tetracarboxylic dianhydride used for the synthesis|combination of polyamic acid is mentioned. The specific example is shown below.

As tetracarboxylic dianhydride which has an alicyclic structure or an aliphatic structure, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutane Tetracarboxylic acid anhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid anhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclo Butanetetracarboxylic acid anhydride, 1,2,3,4-cyclopentanetetracarboxylic acid anhydride, 2,3,4,5-tetrahydrofurantetracarboxylic acid anhydride, 1,2,4,5 -Cyclohexanetetracarboxylic acid anhydride, 3,4-dicarboxy-1-cyclohexylsuccinic acid 2 anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic acid 2 anhydride, 1,2,3,4-butanetetracarboxylic dianhydride, bicyclo[3,3,0]octane-2,4,6,8-tetracarboxylic dianhydride, 3,3',4,4 '-Dicyclohexyltetracarboxylic acid anhydride, 2,3,5-tricarboxycyclopentyl acetic anhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6 -Tetracarboxylic acid anhydride, tricyclo[4.2.1.0 ^2,5 ]nonane-3,4,7,8-tetracarboxylic acid-3,4:7,8-2 anhydride, hexacyclo[6.6.0.1 ^2,7 .1 ^9,14 .0 ^3,6 .0 ^10,13] hexadecane -4,5,11,12- tetracarboxylic acid 4,5: 11,12-2 anhydride, 4- (2 And 5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride.

As aromatic tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxyl Acid 2 anhydride, 2,3,3',4-biphenyltetracarboxylic acid 2 anhydride, 3,3',4,4'-benzophenonetetracarboxylic acid anhydride, 2,3,3',4- Benzophenone tetracarboxylic acid anhydride, bis(3,4-dicarboxyphenyl) ether 2 anhydride, bis(3,4-dicarboxyphenyl)sulfone 2 anhydride, 1,2,5,6-naphthalenetetracarboxylic acid 2 anhydride, 2,3,6,7-naphthalenetetracarboxylic acid anhydride, and the like.

When an aromatic tetracarboxylic dianhydride is used in addition to the tetracarboxylic dianhydride having an alicyclic structure or an aliphatic structure described above, liquid crystal orientation is improved, and accumulated charges in the liquid crystal cell can be reduced. Do.

The tetracarboxylic dianhydride can be used alone or in combination of two or more depending on the characteristics of the liquid crystal aligning property of the liquid crystal alignment film to be formed, voltage retention characteristics, and accumulated charges.

(Polyamic acid)

The polyimide precursor contained in the liquid crystal aligning agent of the present invention includes, in addition to polyamic acid, polyamic acid ester, polyamide, and the like. In addition, it is particularly preferable to select a polyamic acid that is easy to form polyimide.

The polyamic acid preferred as the polyimide precursor contained in the liquid crystal aligning agent of the present invention is obtained by the reaction of the above-described preferred tetracarboxylic acid derivative, tetracarboxylic dianhydride, and the diamine component comprising the above-described diamine compound. You can. When obtaining the polyamic acid, a known synthetic technique can be used. In general, it is a method of reacting a tetracarboxylic dianhydride and a diamine component in an organic solvent. The reaction of the tetracarboxylic dianhydride and the diamine component proceeds relatively easily in an organic solvent, and is advantageous in that by-products do not occur.

And the formed polyamic acid has a metabenzyl type side chain structure by the above-mentioned metabenzyl type diamine compound, and a side chain structure including a photoreactive group enabling photoreaction treatment by the photoreactive diamine compound.

In the metabenzyl type side chain structure, the substituent X ^{1 in} which the benzene ring structure of the metabenzyl type diamine compound of the formula (1) described above forms part of the main chain structure of polyamic acid, and the substituent X ¹ bonded thereto is a side chain structure. It becomes the structure which comprises.

Moreover, it is preferable that the side chain structure containing the photoreactive group which enables photoreaction treatment originates from the photoreactive diamine compound mentioned above, and contains any of the following side chain structures.

delete

delete

In the formula (2A') and the formula (2B'), the broken line represents a linking group of the polyamic acid to the main chain. R, A, B, T ¹ , T ² , T ³ , T ⁴ and S are synonymous with the formulas (2A) and (2B) described above. Specifically, R is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (however, any hydrogen atom may be substituted with a fluorine atom), or an alkoxy group having 1 to 10 carbon atoms (however, any The hydrogen atom may be substituted with a fluorine atom. A and B each independently represent a single bond or any ring structure represented by the following formula. However, any hydrogen atom in the ring structure may be substituted with an alkoxy group having 1 to 10 carbon atoms. T ¹ to T ⁴ each independently represent a single bond, ether, ester, amide or ketone bond. S represents a single bond or an alkylene group having 1 to 10 carbon atoms.)

delete

The organic solvent used for the reaction of the tetracarboxylic dianhydride and the diamine component is not particularly limited as long as the resulting polyamic acid is dissolved. The specific example is given below.

N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, Pyridine, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl Ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol mono Butyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene Glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl- 3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl Ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate , Ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid propyl, 3-methoxypropionic acid butyl, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N,N-dimethylpropanamide, 3-ethoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpro And panamides.

These organic solvents may be used alone or in combination. Moreover, you may use the solvent which does not melt|dissolve a polyamic acid, and you may use it, mixing in the organic solvent mentioned above in the range in which the produced|generated polyamic acid does not precipitate.

Moreover, since moisture in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the resulting polyamic acid, it is preferable to use a dehydrated and dried organic solvent to the extent possible.

When the tetracarboxylic dianhydride and the diamine component are reacted in an organic solvent, the solution in which the diamine component is dispersed or dissolved in the organic solvent is stirred, and the tetracarboxylic dianhydride is added as it is or in the organic solvent. Conversely, a method of adding a diamine component to a solution in which tetracarboxylic dianhydride is dispersed or dissolved in an organic solvent, a method of alternately adding a tetracarboxylic dianhydride and a diamine component, etc. are mentioned. Either method may be used. In addition, when the tetracarboxylic dianhydride or diamine component is composed of a plurality of compounds, the mixture may be reacted in a pre-mixed state, or may be reacted individually individually, or a high molecular weight material may be mixed and reacted individually to react a low molecular weight material. May be

The polymerization temperature at that time can be any temperature of -20°C to 150°C, but is preferably in the range of -5°C to 100°C. Further, the reaction can be carried out at any concentration, but if the concentration is too low, it is difficult to obtain a polymer having a high molecular weight, and if the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring becomes difficult, so tetracarboxyl The total concentration in the reaction solution of the acid 2 anhydride and the diamine component is preferably 1 mass% to 50 mass%, more preferably 5 mass% to 30 mass%. The initial reaction is carried out at a high concentration, after which an organic solvent can be added.

In the above-mentioned reaction, the ratio of the total mole number of the tetracarboxylic dianhydride to the total mole number of the diamine component is preferably 0.8 to 1.2, and more preferably 0.9 to 1.1. As with the conventional polycondensation reaction, the closer this mole ratio is to 1.0, the greater the molecular weight of the resulting polyamic acid.

[Polyamic Acid Ester]

Moreover, as a polyimide precursor of the liquid crystal aligning agent component of this invention, besides the polyamic acid mentioned above, it can also be set as a polyamic acid ester or polyamide.

As a method for synthesizing a preferred polyamic acid ester, the reaction of the tetracarboxylic acid diester dichloride with the preferred diamine component described above, or the tetracarboxylic acid diester with the preferred diamine component described above in the presence of a condensing agent, base, or the like. , There is a way to react. By these methods, a polyamic acid ester which is a kind of a precursor of polyimide can be obtained. Alternatively, the polyamic acid ester can also be obtained by previously polymerizing the polyamic acid and esterifying the carboxylic acid in the amic acid using a polymer reaction.

Specifically, tetracarboxylic acid diester dichloride and the above-described preferred diamine component are in the presence of a base and an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, for 30 minutes to 24 hours , Preferably it can synthesize|combine by reacting for 1 hour-4 hours.

Pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used as the base, but pyridine is preferable because the reaction proceeds gently. It is preferable that it is 2-4 mole times with respect to the tetracarboxylic-acid diester dichloride from a viewpoint that an addition amount of a base is an amount which is easy to remove and it is easy to obtain a high molecular weight body.

When conducting a condensation polymerization reaction in the presence of a condensing agent, triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N' -Carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholinium, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetra Fluoroborate, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluroniumhexafluorophosphite, (2,3-dihydro-2-thioxo-3 -Benzooxazolyl)diphenyl phosphonate, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)4-methoxymorpholinium chloride n-hydrate, and the like can be used.

Moreover, in the method using a condensing agent, when a Lewis acid is added as an additive, the reaction proceeds efficiently. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferred. It is preferable that the addition amount of Lewis acid is 0.1 to 1.0 mole times with respect to the tetracarboxylic-acid diester.

As the solvent, it is possible to use a solvent used to obtain a polyamic acid by polymerizing the above-mentioned tetracarboxylic dianhydride and a preferred diamine component, but from the solubility of the monomer and the resulting polymer, N-methyl-2-pyrrolidone, The use of γ-butyrolactone or the like is preferred. You may use these solvents 1 type or in mixture of 2 or more types. Moreover, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, it is preferable that the solvent used for the synthesis of the polyamic acid ester is dehydrated as much as possible.

The total concentration in the reaction solution of the tetracarboxylic acid diester dichloride and the diamine component is preferably from 1% by mass to 30% by mass, from the viewpoint of precipitation of the polymer less likely to obtain a high molecular weight body, and 5% by mass to 20 mass% is more preferable.

Moreover, it is preferable to perform reaction in nitrogen atmosphere and to prevent mixing of external air.

[Polyamide]

A polyamide preferable as the polyimide precursor described above can also be synthesized in the same manner as the polyamic acid ester described above.

[Polyimide]

As a polymer component contained in the liquid crystal aligning agent of this invention, besides the polyamic acid mentioned above, polyimide becomes a preferable polymer component. The polyimide of the specific structure in this invention can be obtained by carrying out dehydration cyclization (imidation) of the polyamic acid mentioned above.

In the polyimide contained in the liquid crystal aligning agent of the present invention, the dehydration cyclization rate (imidation rate) of the amic acid group is not necessarily 100%, and can be arbitrarily adjusted so as to be 100% or less depending on the purpose and purpose.

Examples of the method for imidizing a polyamic acid include thermal imidization in which the solution of the polyamic acid is directly heated, and catalyst imidation in which a catalyst is added to the solution of the polyamic acid.

The temperature in the case of thermal imidization of the polyamic acid in a solution is 100°C to 400°C, preferably 120°C to 250°C, and a method of carrying out while removing the water produced by the imidization reaction out of the system is preferred. .

The catalyst imidization of the polyamic acid can be carried out by adding a basic catalyst and an acid anhydride to the solution of the 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 mole times of the amic acid group, preferably 2 to 20 mole times of the amic acid group, and the amount of the acid anhydride is 1 to 50 mole times of the amic acid group, preferably 3 to 30 mole times.

Examples of the basic catalyst described above include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like, and among these, pyridine is preferable because it has basicity suitable for advancing the reaction.

Examples of the acid anhydride described above include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Among these, acetic anhydride is preferred because purification after completion of the reaction becomes easy. The imidation rate by catalyst imidation can be controlled by adjusting the catalyst amount, reaction temperature, and reaction time.

[Recovery of polymer]

When the resulting polyamic acid and polyimide are recovered from a reaction solution such as polyamic acid and polyimide of a preferred polymer component obtained by the above-described reaction, the reaction solution is added to a poor solvent, and The polymer can be 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. The polymer precipitated by being introduced into the poor solvent can be dried by heating at room temperature or under normal pressure or reduced pressure after filtration and recovery.

Moreover, if the operation of reprecipitating and recovering the precipitated polymer in an organic solvent and repeating the reprecipitation recovery is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the poor solvent at this time include alcohols, ketones, hydrocarbons, and the like, and the use of three or more poor solvents selected from them is preferable because the purification efficiency increases further.

The molecular weight of the polyamic acid and/or polyimide of the preferred polymer component contained in the liquid crystal aligning agent of the present invention is GPC (Gel (Gel) when considering the strength of the obtained coating film, workability at the time of forming the coating film, and uniformity of the coating film). The weight average molecular weight measured by the Permeation Chromatography) method is preferably 2000 to 1000000, more preferably 5000 to 100000.

〔Crosslinking system〕

The liquid crystal aligning agent of this invention can contain a crosslinking agent other than the polymer component, such as the polyamic acid and/or polyimide mentioned above. By including a crosslinking agent, the crosslinking reaction by the polymer component contained in the liquid crystal aligning agent proceeds, the stability of the pretilt angle formed between the obtained liquid crystal alignment film and the liquid crystal increases, and burn-in of the liquid crystal display element by application of an alternating voltage Can be reduced.

The crosslinking agent is not particularly limited. It is preferable that it is 0.1 mass part-30 mass parts with respect to 100 mass parts of polymer components, such as the polyimide precursor mentioned above contained in a liquid crystal aligning agent, More preferably, it is 1 mass part-20 mass parts. If the amount used is less than 0.1 parts by mass, the effect of crosslinking cannot be expected, and if the amount is more than 30 parts by mass, the alignment of the liquid crystal may deteriorate.

As a preferable crosslinking agent, the compound (hereinafter also referred to as a specific compound) having a structure in which the group represented by formula (3A) is bonded to an aromatic ring is exemplified.

delete

In the formula (3A), Z represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Especially, when Z is a hydrogen atom, the liquid crystal aligning film can increase the pretilt angle of the liquid crystal while maintaining the uniform alignment of the liquid crystal, and can quickly release the charge accumulated in the liquid crystal display element. desirable.

When the specific compound is described in more detail, the specific compound has a structure in which the group represented by the formula (3A) is bonded to the aromatic ring, but the group represented by the formula (3A) (-CH ₂ -OZ group) is directly attached to the aromatic ring. The bonding structure facilitates the binding reaction between the polyamic acid and the polyimide, and also facilitates the magnetic reaction between specific compounds. It is presumed that this is a factor exerting the above-described effect.

Among the specific compounds, at least one compound selected from the group consisting of a compound represented by the following formula (3-1) and a compound represented by the formula (3-2) is preferable.

delete

delete

In the formulas (3-1) and (3-2), Z ₁ , Z ₂ , and Z ₃ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Y ₁ , Y ₂ and Y ₃ Each independently represents an aromatic ring. Any hydrogen atom of the aromatic ring may be substituted with a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, or a vinyl group. G ₁ is a divalent saturated hydrocarbon group having 1 to 10 carbon atoms which may be formed by a single bond, all or a part of which may form a cyclic structure, and any hydrogen atom may be substituted with a fluorine atom, -NH-, -N(CH ₃ )-, or a group represented by the following formula (3B). t ₁ is an integer of 2-4, t ₂ and t ₃ are each independently an integer of 1-3, and a and b are each independently an integer of 1-3.

delete

In Formula (3B), P ₁ and P ₂ are each independently an alkylene group having 1 to 5 carbon atoms, and Q ₁ represents an aromatic ring.

Since the -CH ₂ -OZ ₁ group, -CH ₂ -OZ ₂ group and -CH ₂ -OZ ₃ group of the formulas (3-1) and (3-2) are directly bonded to the aromatic ring, Y ₁ , Y ₂ and Y ₃ are each independently an aromatic ring.

Specific examples of the aromatic ring include benzene ring, naphthalene ring, tetrahydronaphthalene ring, azulene ring, indene ring, fluorene ring, anthracene ring, phenanthrene ring, phenalene ring, pyrrole ring, imidazole ring, oxa Sol ring, thiazole ring, pyrazole ring, pyridine ring, pyrimidine ring, quinoline ring, pyrazoline ring, isoquinoline ring, carbazole ring, purine ring, thiadiazole ring, pyridazine ring, triazine ring, pyra Zolidine ring, triazole ring, pyrazine ring, benzimidazole ring, benzoimidazole ring, chinoline ring, phenanthroline ring, indole ring, quinoxaline ring, benzothiazole ring, phenothiazine ring, acridine ring Rings, oxazole rings, and the like. As a specific example of a more preferable aromatic ring, a benzene ring, a naphthalene ring, a fluorene ring, anthracene ring, a pyrrole ring, an imidazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a quinoline ring, an isoquinoline ring, a carbazole Rings, pyridazine rings, pyrazine rings, benzimidazole rings, benzoimidazole rings, indole rings, quinoxaline rings, acridine rings, and the like. More preferably, it is a benzene ring, a naphthalene ring, a pyridine ring, or a carbazole ring, and most preferably a benzene ring, or a pyridine ring.

Further, the hydrogen atom of these aromatic rings may be substituted with a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, or a vinyl group.

T ₂ and t ₃ in the formula (3-2) are more preferably an integer of 1 or 2. Moreover, a and b are more preferably 1 or 2.

X ₁ in Formula (3-1) and X ₂ and X ₃ in Formula (3-2) are each independently a group consisting of a hydrogen atom, CH ₃ , C ₂ H ₅ and C ₃ H ₇ One group selected from is preferred, the smaller the number of carbon atoms, the better the ease of bonding reaction between polyimide and polyamic acid, or the ease of self-reaction between specific compounds. On the other hand, when the number of carbon atoms increases, the reactivity of the -CH ₂ -OZ ₁ group, -CH ₂ -OZ ₂ group, and -CH ₂ -OZ ₃ group decreases, thereby increasing the storage stability of a solution containing a specific compound. Among them, when Z ₁ in the formula (3-1) and Z ₂ and Z ₃ in the formula (3-2) are hydrogen atoms, the preservation of the liquid crystal is maintained while maintaining a uniform alignment of the liquid crystal. It is preferable because the tilt angle can be increased and the charges accumulated in the liquid crystal display device can be quickly released.

When Z ₁ in the formula (3-2) is a divalent saturated hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, which may be combined with all or part to form a cyclic structure, the Z ₁ Any hydrogen atom possessed may be substituted with a fluorine atom.

Examples of G ₁ include an alkylene group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, an alkylene group and an alicyclic hydrocarbon group, and examples of the group having 1 to 10 carbon atoms are mentioned. . Moreover, the group in which the arbitrary hydrogen atom of the said group was substituted by the fluorine atom is mentioned.

Q ₁ in the upper formula (3B) is an aromatic ring, but specific examples thereof include a benzene ring, a naphthalene ring, a tetrahydronaphthalene ring, an azulene ring, an indene ring, a fluorene ring, anthracene ring, a phenanthrene ring, and a phenane ring. , Pyrrole ring, imidazole ring, oxazole ring, thiazole ring, pyrazole ring, pyridine ring, pyrimidine ring, quinoline ring, pyrazoline ring, isoquinoline ring, carbazole ring, purine ring, thiadiazole ring, Pyridazine ring, triazine ring, pyrazolidine ring, triazole ring, pyrazine ring, benzimidazole ring, benzoimidazole ring, chinoline ring, phenanthroline ring, indole ring, quinoxaline ring, benzothiazole ring , Phenothiazine ring, acridine ring, oxazole ring and the like. Specific examples of the more preferable aromatic ring include benzene ring, naphthalene ring, fluorene ring, anthracene ring, pyrrole ring, imidazole ring, pyrazole ring, pyridine ring, pyrimidine ring, quinoline ring, isoquinoline ring, carbazole Rings, pyridazine rings, pyrazine rings, benzimidazole rings, benzoimidazole rings, indole rings, quinoxaline rings, acridine rings, and the like. More preferably, a benzene ring, a naphthalene ring, a pyridine ring, a carbazole ring, a fluorene ring, etc. are mentioned.

In the liquid crystal aligning agent of this invention, at least 1 type of compound chosen from the group which consists of said Formula (3-1) and said Formula (3-2) can also be used for the preparation.

Although a compound of [P1]-[P45] is mentioned as a specific example of a specific compound used for the liquid crystal aligning agent of this invention, It is not limited to these.

delete

delete

delete

delete

delete

delete

In the above-mentioned specific compound, a compound represented by [P15], [P17], [P19], [P29], [P31], or [P41] is preferable, and among them, [P15], [P17], [P29] ], [P31], or the compound represented by [P41] is more preferable.

(Preparation of liquid crystal aligning agent)

The liquid crystal aligning agent of this invention contains a metabenzyl type side chain structure, such as a polyimide precursor and polyimide obtained by imidizing it, and a side chain containing a photoreactive group which enables photoreaction processing, as mentioned above. It is composed of polymer components of a specific structure having a structure. And the liquid crystal aligning agent in this invention can contain a crosslinking agent.

It is preferable to prepare as a coating liquid so as to be suitable for the formation of the liquid crystal alignment film of the present invention. That is, it is preferable that the liquid crystal aligning agent of this invention is prepared as a solution in which the resin component for forming a resin film is dissolved in the organic solvent. Here, the resin component is a resin component containing the above-described polymer component and the like. At that time, the content of the resin component is preferably 1 mass% to 20 mass%, more preferably 3 mass% to 15 mass%, particularly preferably 3 mass% to 10 mass%.

In the liquid crystal aligning agent of this invention, all of the resin components mentioned above may be polymers of the specific structure mentioned above, but polymers other than them may be mixed. At that time, the content of the other polymer in the resin component is 0.5 mass% to 15 mass%, preferably 1 mass% to 10 mass%.

Such other polymers include, for example, polymers made of polyamic acid or polyimide, etc., which do not have a metabenzyl type side chain structure or a side chain structure including a photoreactive group that enables photoreaction treatment. have.

The organic solvent used for the liquid crystal aligning agent of the present invention is not particularly limited as long as it is an organic solvent that dissolves the resin component and dissolves the crosslinking agent contained when necessary. The specific example is given below.

N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone Don, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, γ-butyrolactone, 3-methoxy-N,N-dimethylpropanamide, 3-ethoxy-N,N-dimethylpropane Amide, 3-butoxy-N,N-dimethylpropanamide, 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclo And hexanone, ethylene carbonate, propylene carbonate, diglyme, and 4-hydroxy-4-methyl-2-pentanone. These may be used alone or in combination. The organic solvent used in the liquid crystal aligning agent of the present invention is preferably N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyllactone.

The liquid crystal aligning agent of this invention may contain components other than the above-mentioned components, such as a polymer of a specific structure. Examples thereof include a solvent or compound that improves film thickness uniformity and surface smoothness when a liquid crystal aligning agent is applied, and a compound that improves adhesion between the liquid crystal alignment film and the substrate.

The following are mentioned as a specific example of the solvent (poor solvent) which improves the uniformity and surface smoothness of a film thickness.

For example, isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl Carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol Monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, propylene glycol monobutyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, di Propylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol , Diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butylbutyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, 1-hexanol, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, 3 -Methyl ethyl ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid propyl, 3-methoxypropionic acid butyl, 1-methoxy-2-propanol, 1 -Ethoxy-2-propanol, 1-butoxy-2-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, dipropylene glycol, 2-(2-ethoxypropoxy)propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, n-butyl lactate, lactate Pediatric wheat ester And a solvent having a low surface tension.

You may use these poor solvents 1 type or in mixture of multiple types. When using the solvent as mentioned above, it is preferable that it is 5 mass%-80 mass% of the whole solvent, More preferably, it is 20 mass so that the solubility of the whole solvent contained in a liquid crystal aligning agent does not fall remarkably. % To 60 mass%. The poor solvent used in the liquid crystal aligning agent of the present invention is preferably butyl cellosolve, propylene glycol monobutyl ether, or dipropylene glycol monomethyl ether.

Examples of the compound that improves the uniformity and surface smoothness of the film thickness include a fluorine-based surfactant, a silicone-based surfactant, and a nonionic surfactant.

Specifically, F-top (registered trademark) 301, EF303, EF352 (manufactured by Tochem Products), Megapack (registered trademark) F171, F173, R-30 (manufactured by DIC), Fluorad FC430, FC431 ( Sumitomo 3M Co., Ltd.), Asahi Guard (registered trademark) AG710 (manufactured by Asahi Glass Corporation), Supron (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by AGC Semichemical) Can be heard. The use ratio of these surfactants is preferably 0.01 parts by mass to 2 parts by mass, more preferably 0.01 parts by mass to 1 part by mass, relative to 100 parts by mass of the resin component contained in the liquid crystal aligning agent.

As a specific example of the compound which improves the adhesiveness of a liquid crystal aligning film and a board|substrate, the functional silane containing compound, epoxy group containing compound, etc. which are shown next are mentioned.

For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3 -Aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxy Carbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetri Amines, 10-trimethoxysilyl-1,4,7-triazadecan, 10-triethoxysilyl-1,4,7-triazadecan, 9-trimethoxysilyl-3,6-diazanonyl Acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3- Aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxyethylene)-3-aminopropyltrimethoxysilane, N-bis(oxyethylene)-3-aminopropyltri Ethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol Diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetra Glycidyl-2,4-hexanediol, N,N,N',N',-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl) And cyclohexane, N,N,N',N',-tetraglycidyl-4,4'-diaminodiphenylmethane.

In the liquid crystal aligning agent of the present invention, as long as the effects of the present invention other than those described above are not impaired, for the purpose of changing electrical properties such as the dielectric constant and conductivity of the liquid crystal aligning film, a dielectric material or a conductive material, furthermore, a liquid crystal aligning film A crosslinkable compound may be added for the purpose of increasing the hardness and density of the film when it is made.

<Liquid crystal alignment film and liquid crystal display element>

The liquid crystal aligning agent of the present invention described above is coated on a substrate and fired similarly to the liquid crystal aligning agent for forming a liquid crystal aligning film made of a conventional polyimide, without applying any other method. The liquid crystal aligning film in this invention can be formed. And the orientation control ability can be provided by performing photo-alignment process by light irradiation, and it can be used for manufacture of a liquid crystal display element.

As a substrate used when the liquid crystal aligning agent of the present invention is applied to form a liquid crystal alignment film, when the manufactured liquid crystal display element is of a transmissive type, a substrate having high transparency is preferably used. In that case, it is not particularly limited, and a glass substrate or a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used. Further, for driving the liquid crystal in the liquid crystal display device, it is preferable from the viewpoint of simplifying the manufacturing process to use a substrate on which a transparent electrode such as an ITO (Indium Tin Oxide) electrode is formed. In addition, in the reflection type liquid crystal display element, an opaque one such as a silicon wafer can be used as long as it is only on one side of the substrate, and the electrode in this case can be made of a material that reflects light such as aluminum.

In the formation of the liquid crystal aligning film of the present invention, the method for applying the liquid crystal aligning agent in the present invention is not particularly limited. As a method for applying the liquid crystal aligning agent, screen printing, offset printing, flexo printing, inkjet, and the like are generally industrially used. As other coating methods, there is a method of using a dip, roll coater, slit coater, spinner, or the like, and these may be used depending on the purpose.

Firing after applying the liquid crystal aligning agent of the present invention on a substrate is carried out at 50°C to 300°C, preferably 80°C to 250°C by heating means such as a hot plate, and for example, a solvent which is an organic solvent is used. By evaporation, a coating film can be formed. When the thickness of the coating film formed after firing is too thick, it is disadvantageous in terms of power consumption when used in a liquid crystal display element, and if it is too thin, reliability of the liquid crystal display element may be deteriorated. Therefore, the thickness of the coating film after firing is preferably 5 nm to 300 nm, more preferably 10 nm to 100 nm.

When the liquid crystal is vertically aligned while forming the pretilt angle, the coated film after firing is treated with polarized ultraviolet radiation. That is, photo-alignment processing is performed. Moreover, the liquid crystal aligning film in this invention can also provide orientation control ability, especially a pretilt angle, by rubbing treatment.

The liquid crystal display element of this invention obtains the liquid crystal aligning film formation substrate in which the liquid crystal aligning film of this invention was formed from the liquid crystal aligning agent of this invention by the method mentioned above, and produces a liquid crystal cell by a well-known method, and a liquid crystal display element It is done. In the present invention, a VA mode liquid crystal display element can be provided.

As an example of manufacturing a liquid crystal cell, a pair of substrates on which the liquid crystal alignment film of the present invention is formed is prepared, a spacer is scattered on the liquid crystal alignment film of one substrate, and the liquid crystal alignment film surface is inside, so that the other substrate is A method of bonding, sealing the liquid crystal under reduced pressure and sealing it, or dropping the liquid crystal onto the surface of the liquid crystal alignment film scattering the spacer, and then bonding the substrate and performing sealing can be exemplified. The diameter of the spacer at this time is preferably 1 μm to 30 μm, more preferably 2 μm to 10 μm. The spacer diameter determines the distance between a pair of substrates that sandwich the liquid crystal layer, that is, the thickness of the liquid crystal layer.

As described above, the liquid crystal display element produced using the liquid crystal aligning agent of the present invention has excellent reliability, excellent display quality, and can be suitably used for a large-screen, high-definition liquid crystal television.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. In addition, this invention is limited to these and is not interpreted. The main compounds used in Synthesis Examples and Examples, and their codes and structures are as follows.

(Tetracarboxylic dianhydride)

BODA: Bicyclo[3,3,0]octane-2,4,6,8-tetracarboxylic dianhydride

CBDA: 1,2,3,4-cyclobutanetetracarboxylic acid anhydride

(Diamine)

DA-1: Compound represented by the following formula

delete

DA-2: Compound represented by the following formula

delete

DA-3: Compound represented by the following formula

delete

DA-4: Compound represented by the following formula

delete

DA-5: Compound represented by the following formula

delete

DA-6: Compound represented by the following formula

delete

DA-7: Compound represented by the following formula

delete

(Crosslinking system)

TM-BIP: 2,2'-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane

(menstruum)

NMP: N-methyl-2-pyrrolidone

BCS: Butyl Cellosolve

Next, a method of measuring the molecular weight and measuring the imidation rate of the polyimide will be described.

[Molecular weight measurement]

The molecular weight of the polyimide was measured as follows using a room temperature gel permeation chromatography (GPC) apparatus (SSC-7200) manufactured by Senshu Science and a column (KD-803, KD-805) manufactured by Shodex.

Column temperature: 50 ℃

Eluent: N,N'-dimethylformamide (as an additive, lithium bromide-hydrate (LiBrH2O) is 30 mmol/L, phosphoric anhydride (o-phosphoric acid) is 30 mmol/L, tetrahydrofuran ( THF) teeth 10 ml/ℓ)

Flow rate: 1.0 ml/min

Standard sample for calibration curve preparation: TSK standard polyethylene oxide (molecular weights about 9000000, 150000, 100000, 30000) manufactured by Tosoh Corporation, and polyethylene glycol (molecular weights about 12000, 4000, 1000) manufactured by Polymer Laboratories.

[Measurement of imidization rate]

The imidation ratio of polyimide was measured as follows. 20 mg of the polyimide powder was placed in an NMR sample tube (NMR sampling tube standard φ5 manufactured by Kusano Science Co., Ltd.), and 1.0 mL of deuterated dimethyl sulfoxide (DMSO-d ₆ , 0.05% TMS mixture) was added, and completely dissolved by adding ultrasound. Ordered. This solution was measured for a 500 MHz proton NMR by an NMR meter (JNW-ECA500) manufactured by Nippon Electronics Datum. The imidation rate is determined by using a proton derived from a structure that does not change before and after imidization as a reference proton, and the peak integrated value of this proton and a proton peak derived from the NH group of amic acid appearing at around 9.5 to 10.0 ppm. It calculated|required by the following formula using the integrated value. In addition, in the following formula, x is a proton peak integrated value derived from the NH group of amic acid, y is a peak integrated value of a reference proton, α is polyamic acid (the imidation rate is 0%), and The ratio of the number of reference protons to one proton of the NH group.

[Equation 1]

Imidation rate (%) = (1-α·x/y) × 100

(Synthesis Example 1)

BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), and DA-1 (1.04 g, 2.4 mmol) were dissolved in NMP (29.27 g) and reacted at 80°C for 7 hours. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.76 g) were added and reacted at 40°C for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42 g) and diluting it to 6 mass%, acetic anhydride (4.22 g) and pyridine (2.73 g) were added as an imidization catalyst and reacted at 80°C for 4 hours. This reaction solution was poured into methanol (520 mL), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain polyimide powder (A1). The imidation ratio of this polyimide was 60%, the number average molecular weight was 10000, and the weight average molecular weight was 35000.

NMP (44.0 g) was added to the obtained polyimide powder (A1) (6.0 g) and stirred at 50°C for 12 hours to dissolve. Liquid crystal aligning agent (B1) was obtained by adding BCS (50.0 g) to this solution, and stirring at 50 degreeC for 5 hours.

(Synthesis Example 2)

BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), and DA-3 (1.08 g, 2.4 mmol) were dissolved in NMP (29.37 g) and reacted at 80°C for 7 hours. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.79 g) were added and reacted at 40°C for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42 g) and diluting it to 6 mass%, acetic anhydride (4.21 g) and pyridine (2.72 g) were added as an imidization catalyst and reacted at 80°C for 4 hours. This reaction solution was poured into methanol (520 mL), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain polyimide powder (A2). The imidation ratio of this polyimide was 60%, the number average molecular weight was 12000, and the weight average molecular weight was 38000.

NMP (44.0 g) was added to the obtained polyimide powder (A2) (6.0 g) and stirred at 50°C for 12 hours to dissolve. Liquid crystal aligning agent (B2) was obtained by adding BCS (50.0 g) to this solution, and stirring at 50 degreeC for 5 hours. The liquid crystal aligning agent (B2) becomes a liquid crystal aligning agent containing a polyimide having the above-described metabenzyl type side chain structure and a side chain structure containing a photoreactive group that enables photoreaction treatment.

(Synthesis Example 3)

The crosslinking agent TM-BIP was added to 10.0 g of the liquid crystal aligning agent (B2), and 0.03 g (5% by mass based on the solid content) was added and stirred at room temperature for 3 hours to dissolve to prepare the liquid crystal aligning agent (B3).

(Synthesis Example 4)

A crosslinking agent TM-BIP was added to 10.0 g of the liquid crystal aligning agent (B2), 0.06 g (10 mass% based on the solid content), and stirred at room temperature for 3 hours to dissolve, to prepare a liquid crystal aligning agent (B4).

(Synthesis Example 5)

BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), and DA-4 (0.91 g, 2.4 mmol) were dissolved in NMP (28.88 g) and reacted at 80°C for 7 hours. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.63 g) were added and reacted at 40°C for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42 g) and diluting it to 6 mass%, acetic anhydride (4.28 g) and pyridine (2.76 g) were added as an imidization catalyst and reacted at 80°C for 4 hours. This reaction solution was poured into methanol (520 mL), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain polyimide powder (A3). The imidation ratio of this polyimide was 60%, the number average molecular weight was 10000, and the weight average molecular weight was 35000.

NMP (44.0 g) was added to the obtained polyimide powder (A3) (6.0 g) and stirred at 50°C for 12 hours to dissolve. Liquid crystal aligning agent (B5) was obtained by adding BCS (50.0 g) to this solution, and stirring at 50 degreeC for 5 hours.

(Synthesis Example 6)

BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), and DA-6 (0.95 g, 2.4 mmol) were dissolved in NMP (28.98 g) and reacted at 80°C for 7 hours. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.66 g) were added and reacted at 40°C for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42 g) and diluting it to 6 mass%, acetic anhydride (4.26 g) and pyridine (2.75 g) were added as an imidization catalyst and reacted at 80°C for 4 hours. This reaction solution was poured into methanol (520 mL), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain polyimide powder (A4). The imidation ratio of this polyimide was 60%, the number average molecular weight was 12000, and the weight average molecular weight was 38000.

NMP (44.0 g) was added to the obtained polyimide powder (A4) (6.0 g) and stirred at 50°C for 12 hours to dissolve. Liquid crystal aligning agent (B6) was obtained by adding BCS (50.0 g) to this solution, and stirring at 50 degreeC for 5 hours. The liquid crystal aligning agent (B6) becomes a liquid crystal aligning agent containing a polyimide having the above-described metabenzyl type side chain structure and a side chain structure including a photoreactive group enabling photoreaction treatment.

(Synthesis Example 7)

A crosslinking agent TM-BIP was added to 10.0 g of the liquid crystal aligning agent (B6), 0.03 g (5% by mass relative to the solid content), and stirred at room temperature for 3 hours to dissolve to prepare the liquid crystal aligning agent (B7).

(Synthesis Example 8)

The crosslinking agent TM-BIP was added to 10.0 g of the liquid crystal aligning agent (B6) (0.06 g based on solid content), and the mixture was stirred and dissolved at room temperature for 3 hours to prepare a liquid crystal aligning agent (B8).

(Synthesis Example 9)

BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), and DA-2 (1.11 g, 2.4 mmol) were dissolved in NMP (29.47 g) and reacted at 80°C for 7 hours. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.82 g) were added and reacted at 40°C for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42 g) and diluting it to 6 mass%, acetic anhydride (4.19 g) and pyridine (2.71 g) were added as an imidization catalyst and reacted at 80°C for 4 hours. This reaction solution was poured into methanol (520 mL), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain polyimide powder (A5). The imidation ratio of this polyimide was 60%, the number average molecular weight was 12000, and the weight average molecular weight was 38000.

NMP (44.0 g) was added to the obtained polyimide powder (A5) (6.0 g) and stirred at 50°C for 12 hours to dissolve. Liquid crystal aligning agent (B9) was obtained by adding BCS (50.0 g) to this solution, and stirring at 50 degreeC for 5 hours.

(Synthesis Example 10)

BODA (3.00 g, 12.0 mmol), DA-7 (4.96 g, 13.6 mmol), and DA-5 (0.98 g, 2.4 mmol) were dissolved in NMP (29.08 g) and reacted at 80°C for 7 hours. Then, CBDA (0.75 g, 3.8 mmol) and NMP (9.69 g) were added and reacted at 40°C for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (42 g) and diluting it to 6 mass%, acetic anhydride (4.25 g) and pyridine (2.74 g) were added as an imidization catalyst and reacted at 80°C for 4 hours. This reaction solution was poured into methanol (520 mL), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain polyimide powder (A6). The imidation ratio of this polyimide was 60%, the number average molecular weight was 12000, and the weight average molecular weight was 38000.

NMP (44.0 g) was added to the obtained polyimide powder (A6) (6.0 g), and the mixture was dissolved by stirring at 50°C for 12 hours. Liquid crystal aligning agent (B10) was obtained by adding BCS (50.0 g) to this solution, and stirring at 50 degreeC for 5 hours.

<Formation of a liquid crystal alignment film and production of a liquid crystal cell>

(Comparative Example 1)

The liquid crystal aligning agent (B1) obtained in Synthesis Example 1 was spin-coated on the ITO surface of a glass substrate on which a transparent electrode made of an ITO film was formed, and dried on a hot plate at 80°C for 90 seconds, followed by a hot air circulation oven at 200°C Was fired for 30 minutes to form a liquid crystal alignment film having a film thickness of 100 nm.

This substrate was irradiated with 20 mJ of linearly polarized UV at 313 nm with an irradiation intensity of 10.0 mW/cm ^-2 to perform photo alignment treatment. The direction of the incident light beam was inclined 40° relative to the normal direction of the substrate. The linearly polarized UV was prepared by passing a 313 nm band pass filter through ultraviolet light of a high pressure mercury lamp and then passing a 313 nm polarizing plate.

After dispersing a 6 µm bead spacer on the liquid crystal alignment film of one of the two substrates, a sealing agent (solvent type thermosetting type epoxy resin) was printed thereon. Subsequently, the side of the other side of the substrate on which the liquid crystal alignment film was formed was placed inside, and after bonding with the previous substrate, the sealing agent was cured to produce an empty cell. Liquid crystal MLC-6608 (trade name manufactured by Merck Corporation) was injected into the blank cell by a reduced pressure injection method to prepare a liquid crystal cell.

The pretilt angle of the obtained liquid crystal cell was measured by the following method.

Thereafter, an AC voltage (AC) of 30 kHz and 20 V _{p- p} was applied to the liquid crystal cell at room temperature for 168 hours (AC drive). Then, the pretilt angle was measured again, and the change of the pretilt angle (pretilt angle change) before and after AC driving was evaluated. Table 1 shows the results.

[Pretilt angle measurement]

The pretilt angle of the liquid crystal cell was measured by the Muller matrix method using "Axo Scan" manufactured by Axo Metrix.

(Example 1)

A liquid crystal aligning film was formed by performing the same operation as in Comparative Example 1, except that the liquid crystal aligning agent (B2) was used instead of the liquid crystal aligning agent (B1), and the pretilt angle was changed before and after AC driving of the liquid crystal cell produced using the same. Was evaluated.

(Example 2)

The liquid crystal aligning film was formed by performing the same operation as in Comparative Example 1, except that the liquid crystal aligning agent (B3) was used instead of the liquid crystal aligning agent (B1), and the pretilt angle change before and after AC driving of the liquid crystal cell produced using the same was performed. Evaluated.

(Example 3)

A liquid crystal aligning film was formed by performing the same operation as in Comparative Example 1, except that the liquid crystal aligning agent (B4) was used instead of the liquid crystal aligning agent (B1), and the pretilt angle change before and after AC driving of the liquid crystal cell produced using the same was performed. Evaluated.

(Comparative Example 3)

A liquid crystal aligning film was formed by performing the same operation as in Comparative Example 1 except that the liquid crystal aligning agent (B5) was used instead of the liquid crystal aligning agent (B1), and the pretilt angle change before and after AC driving of the liquid crystal cell produced using the same was performed. Evaluated.

(Example 4)

A liquid crystal aligning film was formed by performing the same operation as in Comparative Example 1, except that the liquid crystal aligning agent (B6) was used instead of the liquid crystal aligning agent (B1), and the pretilt angle change before and after AC driving of the liquid crystal cell produced using the same was performed. Evaluated.

(Example 5)

A liquid crystal aligning film was formed by performing the same operation as in Comparative Example 1, except that the liquid crystal aligning agent (B7) was used instead of the liquid crystal aligning agent (B1), and the pretilt angle change before and after AC driving of the liquid crystal cell produced using the same was performed. Evaluated.

(Example 6)

The liquid crystal aligning film was formed by performing the same operation as in Comparative Example 1, except that the liquid crystal aligning agent (B8) was used instead of the liquid crystal aligning agent (B1), and the pretilt angle change before and after AC driving of the liquid crystal cell produced using the same was performed. Evaluated.

(Comparative Example 2)

A liquid crystal aligning film was formed by performing the same operation as in Comparative Example 1, except that the liquid crystal aligning agent (B9) was used instead of the liquid crystal aligning agent (B1), and the pretilt angle change before and after AC driving of the liquid crystal cell produced using the same was performed. Evaluated.

(Comparative Example 4)

A liquid crystal aligning film was formed by performing the same operation as in Comparative Example 1, except that the liquid crystal aligning agent (B10) was used instead of the liquid crystal aligning agent (B1), and the pretilt angle change before and after AC driving of the liquid crystal cell produced using the same was performed. Evaluated.

The evaluation results of Examples 1 to 6 and Comparative Examples 1 to 4 described above are collectively shown in Table 1 and FIG. 1 below.

1 is a graph showing comparison of evaluation results of a liquid crystal cell of an example of the present invention.

The liquid crystal cells produced in Examples 1 and 4 include a liquid crystal orientation containing a polyimide having the above-described metabenzyl type side chain structure and a side chain structure including a photoreactive group enabling photoreaction treatment. It becomes a liquid crystal cell which has the liquid crystal aligning film formed using the agent (B2) and the liquid crystal aligning agent (B6). In addition, the liquid crystal cells produced in Examples 2 and 3 and Examples 5 and 6 include a side chain structure of the above-described metabenzyl type and a photoreactive group enabling photoreaction treatment. It becomes a liquid crystal cell which has a liquid crystal aligning film formed using the liquid crystal aligning agent (B3) containing a polyimide which has a structure, and a crosslinking agent, a liquid crystal aligning agent (B4), a liquid crystal aligning agent (B7), and a liquid crystal aligning agent (B7).

And, for example, the liquid crystal cell produced in Comparative Example 1 and Comparative Example 3 contains a polyimide having an orthoether type side chain structure and a side chain structure including a photoreactive group that enables photoreaction treatment. It becomes a liquid crystal cell which has a liquid crystal aligning film formed using the aligning agent (B1) and a liquid crystal aligning agent (B5).

As shown in Table 1 and FIG. 1, in the liquid crystal cells of Examples 1 and 4, compared with Comparative Example 1 and Comparative Example 3, the change in the pretilt angle by AC driving (the change in the pretilt angle in Table 1) (Shown as (°)) was confirmed to be suppressed.

Moreover, in the liquid crystal cell of Example 2, Example 3, Example 5, and Example 6, it was confirmed that the change in the pretilt angle by AC drive was further suppressed by the effect of the crosslinking agent contained in the liquid crystal aligning agent.

From the above, the VA mode liquid crystal display using the liquid crystal aligning film obtained from the liquid crystal aligning agent containing the polybenzyl which has the metabenzyl type side chain structure of this Example and the side chain structure containing the photoreactive group which enables photoreaction processing. It has been found that the device can reduce burn-in by applying an alternating voltage. That is, the liquid crystal aligning film obtained from the liquid crystal aligning agent containing polyimide which has the metabenzyl type side chain structure of this Example and the side chain structure containing the photoreactive group which enables photoreaction processing is used for application of alternating voltage. It has been found that it is preferable to provide a VA mode liquid crystal display device with reduced burn-in.

Industrial availability

The liquid crystal aligning agent of this invention can provide a liquid crystal aligning film of vertical alignment which can perform photo-alignment process and is effective in improving display defects, such as burn-in. Therefore, it is possible to manufacture a VA mode liquid crystal display device having excellent display quality with high productivity, which is preferable for manufacturing a liquid crystal display device for a portable information terminal such as a large-sized liquid crystal TV or a smartphone displaying a high-definition image. Can be used. That is, the liquid crystal display device of the present invention having the liquid crystal alignment film of the present invention constitutes a VA mode liquid crystal display device of high display quality, and displays for a portable information terminal such as a large-sized TV or a smartphone displaying a high-definition image. It can be preferably used as an element.

In addition, the entire content of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2012-224017, filed on October 9, 2012, is cited herein, and accepted as the disclosure of the specification of the present invention.

Claims (10)

It is characterized by containing at least one polymer selected from the group consisting of a polyimide precursor having a metabenzyl type side chain structure and a side chain structure containing a photoreactive group, and a polyimide obtained by imidizing the polyimide precursor. As a liquid crystal aligning agent to say,
A liquid crystal aligning agent which is a polyamic acid obtained by reacting a diamine component containing a first diamine compound represented by the following formula (1) with the polyimide precursor, and a second diamine compound having the photoreactive group, and tetracarboxylic dianhydride.

(X ¹ is a group represented by the following formula (1A))

(Y ¹ is -O-, -CH ₂ O-, -COO- or -OCO-. Y ² is a single bond or -(CH ₂ ) _b- (b is an integer from 1 to 15). Y ³ Is a single bond, -(CH ₂ ) _c- (c is an integer from 1 to 15), -O-, -CH ₂ O-, -COO- or -OCO- Y ⁴ is a benzene ring, cyclohexane ring And a cyclic group selected from the group consisting of heterocyclic rings, or a divalent organic group selected from the group consisting of organic groups having 12 to 25 carbon atoms having a steroid skeleton, wherein any hydrogen atom on the cyclic group is 1 to 3 carbon atoms. It may be substituted with an alkyl group, a C1-C3 alkoxy group, a C1-C3 fluorine-containing alkyl group, a C1-C3 fluorine-containing alkoxy group, or a fluorine atom. Y ⁵ is a benzene ring, cyclohexane ring or heterocyclic ring. It is a cyclic group selected from the group consisting of, wherein any hydrogen atom on the cyclic group is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine having 1 to 3 carbon atoms It may be substituted with a containing alkoxy group or a fluorine atom Y ⁶ is a C1-C18 alkyl group, a C1-C18 fluorine-containing alkyl group, a C1-C18 alkoxy group or a C1-C18 fluorine-containing alkoxy group n Is an integer from 0 to 4.) According to claim 1,
The liquid crystal aligning agent which is the said photoreactive group of the said 2nd diamine compound causes either a photodimerization reaction and a photoisomerization reaction. According to claim 1,
A liquid crystal aligning agent having at least one structure selected from the group consisting of a cinnamoyl structure, a coumarin structure and a chalcone structure, wherein the photo-reactive group of the second diamine compound. According to claim 1,
A liquid crystal aligning agent comprising a structure represented by any one of the following formula (2A) and the following formula (2B) in the photoreactive group of the second diamine compound.

(R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, provided that any hydrogen atom of the alkyl group and the alkoxy group may be substituted with a fluorine atom. A and B each independently represents any one of a ring structure represented by a single bond or the following formula. However, any of the hydrogen atoms in the ring structure is optionally substituted with an alkoxy group having a carbon number of ^{1 ~ 10. T 1 ~ T} 4 is , Each independently represents a single bond, ether, ester, amide or ketone bond, S represents a single bond or an alkylene group having 1 to 10 carbon atoms.)

According to claim 1,
The liquid crystal aligning agent whose content of the 1st diamine compound contained in the said diamine component is 5 mol%-50 mol%, and the content of the 2nd diamine compound is 20 mol%-95 mol%. According to claim 1,
The liquid crystal aligning agent whose content of the said polymer is 1-20 mass %. According to claim 1,
A liquid crystal aligning agent further comprising a crosslinking agent. The liquid crystal aligning film obtained using the liquid crystal aligning agent in any one of Claims 1-7. The liquid crystal display element which has the liquid crystal aligning film of Claim 8. delete

Images