CN121109009A - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal element using same - Google Patents

Abstract

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film and a liquid crystal element using the same. A liquid crystal aligning agent comprising a polymer (K) and a polymer (L) which are polymers obtained by reacting a tetracarboxylic acid derivative with diamines, wherein the raw material composition of the polymer (K) comprises at least one of the tetracarboxylic acid derivatives represented by the formula (I) and comprises at least one of diamines having a Boc structure, the raw material composition of the polymer (L) does not contain the tetracarboxylic acid derivatives represented by the formula (I) and does not contain diamines having a Boc structure,In the formula (I), 1', 2 and 2' are bond, each independently bond to a hydroxyl group, a chlorine atom or an alkoxy group having 1 to 6 carbon atoms, at least one of the group of 1 and 1 'and the group of 2 and 2' is capable of bonding to the same oxygen atom, and R ^b1、R^b2、R^b3 and R ^b4 are each independently a hydrogen atom or a methyl group, at least one of them is a methyl group.

Description

Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal element using same

Technical Field

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film and a liquid crystal element using the same. More specifically, the present invention relates to a liquid crystal alignment agent for photo-alignment (hereinafter, abbreviated as a liquid crystal alignment agent) for forming a liquid crystal alignment film of photo-alignment type (hereinafter, abbreviated as a photo-alignment film), a liquid crystal alignment film of photo-alignment type formed by using the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film (hereinafter, abbreviated as a liquid crystal element).

Background

A liquid crystal device is known in which an optical phenomenon such as refraction, scattering, reflection, etc. can be caused by controlling or modulating an alignment state of a liquid crystal layer in the device. Specifically, a liquid crystal antenna, a dimming window, an optical compensation material, and a variable phase shifter are known in addition to the liquid crystal display element described below.

As liquid crystal display elements, various driving modes such as a TN (TWISTED NEMATIC ) mode, an STN (Super TWISTED NEMATIC, super twisted nematic) mode, an IPS (In-PLANE SWITCHING ) mode, an FFS (FRINGE FIELD SWITCHING, fringe field switching) mode, and a vertically aligned VA (Multi-domain VERTICAL ALIGNMENT ) mode are known. These liquid crystal display elements are used in image display devices of various electronic devices such as televisions and mobile phones, and have been developed with a view to further improving display quality. Specifically, the performance of the liquid crystal display element is improved not only by the driving method and the improvement of the element structure but also by the constituent members used in the element. Among the constituent members used in liquid crystal display devices, particularly, a liquid crystal alignment film is one of important materials related to display quality, and in order to meet the demand for higher quality of liquid crystal display devices, research into such a liquid crystal alignment film has been actively conducted.

The liquid crystal alignment film has a function of being provided on a pair of substrates provided on both sides of a liquid crystal layer of the liquid crystal display element, and being in contact with the liquid crystal layer, so that liquid crystal molecules constituting the liquid crystal layer are aligned with respect to the substrates at a constant regularity. By using a liquid crystal alignment film having high liquid crystal alignment properties, a liquid crystal display element having high contrast and improved afterimage characteristics can be realized (for example, refer to patent documents 1 and 2).

In recent years, in liquid crystal display devices, the frame is narrowed, and the frame of the display screen is narrowed. Here, in order to widen the display area for narrowing the frame, it is necessary to print a liquid crystal alignment film on an end portion of the substrate, and apply a sealant to the liquid crystal alignment film. Under such circumstances, liquid crystal alignment films having high adhesion to a sealant have been developed (for example, patent documents 7 to 9).

In the formation of such a liquid crystal alignment film, a solution (varnish) obtained by dissolving a polyamic acid, a soluble polyimide or a polyamic acid ester in an organic solvent has been mainly used. In order to form a liquid crystal alignment film using these varnishes, the varnish is applied to a substrate, and then the coating film is cured by heating or the like to form a polyimide-based liquid crystal alignment film, and if necessary, an alignment treatment suitable for the display mode described above is performed. As an alignment treatment method, there are known a rubbing method in which the direction of polymer molecules is adjusted by wiping the surface of an alignment film with a cloth or the like, and a photo-alignment method in which the polymer molecules are photochemically changed by irradiation of the alignment film with ultraviolet rays of linearly polarized light to cause photodecomposition, photoisomerization, dimerization, or the like, and anisotropy is imparted to the film, and among these, the photo-alignment method has advantages such as high uniformity of alignment compared with the rubbing method, and no damage to the film due to a non-contact alignment treatment method, and the reduction of display failure of a liquid crystal display element such as dust generation or static electricity.

As a liquid crystal alignment film using such a photo-alignment method, for example, patent documents 1 to 5 describe a technique of applying photoisomerization using diaminoazobenzene or the like as a raw material to obtain a photo-alignment film having a large anchoring energy and good liquid crystal alignment property. Patent document 6 describes that a photo-alignment film having high transparency and good liquid crystal alignment is obtained by applying a photo-decomposition technique.

However, the liquid crystal alignment film obtained by the photo-alignment method has a problem of smaller anisotropy with respect to the alignment direction of the polymer film than the liquid crystal alignment film by the rubbing treatment. If the anisotropy is small, sufficient liquid crystal alignment cannot be obtained, and when a liquid crystal display element is produced, problems such as occurrence of afterimage occur. In addition, as a method for improving the anisotropy of a liquid crystal alignment film obtained by a photo-alignment method, it has been proposed to remove a low molecular weight component generated by cutting a main chain of a polymer by irradiation after light irradiation (see patent document 10).

Prior art literature

Patent literature

Patent document 1, japanese patent application laid-open No. 2010-197999;

patent document 2, international publication No. 2013/157463;

Patent document 3, japanese patent laid-open publication No. 2005-275364;

patent document 4, japanese patent laid-open No. 2007-248637;

Patent document 5, international publication No. 2015/016118;

patent document 6, japanese patent laid-open publication No. 2012-155311;

patent document 7, japanese patent laid-open No. 2017-198975;

Patent document 8 International publication No. 2016/043230;

patent document 9, japanese patent application laid-open No. 2018-106096;

patent document 10, japanese patent application laid-open No. 2011-107266.

Disclosure of Invention

In recent years, applications of liquid crystal display elements have been widely related to monitors for personal computers, liquid crystal televisions, mobile phones, display units for smart phones, and medical monitors. Further, a more excellent display quality is demanded, and an afterimage is given as an important characteristic affecting the display quality. In the photo-alignment film, it is effective to increase the content of the photosensitive portion in order to improve the afterimage, but if the content of the photosensitive portion is too large, a bright spot defect derived from the photodecomposition product occurs. In addition, although the use of soluble polyimide or polyamic acid ester is effective in improving afterimage, there is a problem in that the solubility of varnish is low.

Accordingly, the present inventors have made intensive studies with the object of providing a liquid crystal alignment film capable of forming a liquid crystal display element having excellent display quality and excellent residual image characteristics, which is capable of suppressing a bright spot failure from a photodecomposition, and providing a liquid crystal alignment agent for photo-alignment, which is capable of forming such a liquid crystal alignment film and has high solubility.

The present inventors have found that the above problems can be solved by a liquid crystal aligning agent for photo-alignment comprising a polymer (K) containing a compound represented by formula (1) and a diamine having a Boc structure, and a polymer (L) not containing a compound represented by formula (1) and a diamine having a Boc structure, and have completed the present invention.

The present invention includes the following structures.

[1] A liquid crystal aligning agent comprising a polymer (K) and a polymer (L) which are obtained by reacting a tetracarboxylic acid derivative with a diamine,

The raw material composition of the polymer (K) comprises at least one of the tetracarboxylic acid derivatives shown in the formula (I) and at least one of the diamines with a Boc structure,

The raw material composition of the polymer (L) contains no tetracarboxylic acid derivative represented by the formula (I) and contains no diamine having a Boc structure,

In the formula (I), 1', 2 and 2' are bond, each independently bond with hydroxyl, chlorine atom or alkoxy with 1-6 carbon atoms, at least one of the group of 1 and 1 'and the group of 2 and 2' can bond with the same oxygen atom,

R ^b1、R^b2、R^b3 and R ^b4 are each independently a hydrogen atom or a methyl group, at least one of which is a methyl group.

[2] The liquid crystal aligning agent according to [1], wherein the polymer (K) and the polymer (L) are polyamic acids.

[3] The liquid crystal aligning agent according to [1], wherein the diamine having a Boc structure comprises at least one of compounds represented by the formula (DI-17-2),

In the formula (DI-17-2), e is an integer of 1 to 10, and Boc is a tert-butoxycarbonyl group.

[4] The liquid crystal aligning agent according to [1], wherein the raw material composition of the polymer (L) comprises at least one of the compounds represented by the formula (DI-5) or the formula (DI-6),

In the formula (DI-5), G ³³ is a single bond 、-NCH₃-、-O-、-S-、-S-S-、-SO₂-、-CO-、-COO-、-CONCH₃-、-CONH-、-C(CH₃)₂-、-C(CF₃)₂-、-(CH₂)_m-、-O-(CH₂)_m-O-、-(O-C₂H₄)_m-O-、-O-CH₂-C(CF₃)₂-CH₂-O-、-O-CO-(CH₂)_m-CO-O-、-CO-O-(CH₂)_m-O-CO- or-S- (CH ₂)_m -S-, or a group represented by the following formula (DI-5-a) or the following formula (DI-5-b), m is independently an integer of 1 to 12,

In the formula (DI-5-a), q is an integer of 0 to 6, R ⁴⁴ is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms,

In the formula (DI-6) and the formula (DI-7), G ²¹ and G ²² are independently a single bond, -O-, -S-, -CO-, -C (CH ₃)₂-、-C(CF₃)₂ -, or an alkylene group having 1 to 10 carbon atoms).

[5] The liquid crystal aligning agent according to [1], wherein the ratio of the polymer (K) in the liquid crystal aligning agent is 40% by weight or less.

[6] The liquid crystal aligning agent according to [1], wherein the compound represented by the formula (I) is a compound represented by the formula (I-1).

[7] The liquid crystal aligning agent according to [1], wherein in the formula (DI-17-2), e is an integer of 2 to 6.

[8] The liquid crystal aligning agent according to [1], wherein in the formula (DI-17-2), e is 2,4 or 6.

[9] The liquid crystal aligning agent according to [4], wherein in the formula (DI-5), G ³³ is-O-or-CH ₂ -, or in the formula (DI-6), G ²¹ and G ²² are-O-.

[10] A liquid crystal aligning agent for a photo-alignment type transverse electric field type liquid crystal display element, of the liquid crystal aligning agents described in any one of [1] to [9 ].

[11] A liquid crystal alignment film formed from the liquid crystal alignment agent described in any one of [1] to [10 ].

[12] A liquid crystal element having the liquid crystal alignment film of [11 ].

[13] A method for producing a liquid crystal alignment film, comprising the steps of:

coating the liquid crystal aligning agent of any one of [1] to [10] on a substrate;

firing the substrate, and

And irradiating the substrate with polarized ultraviolet rays.

By using the liquid crystal aligning agent for photo-alignment of the present invention, a liquid crystal alignment film having excellent display quality and capable of forming a liquid crystal display element having excellent residual image characteristics and suppressed bright point defects derived from photodecomposition products can be obtained. Further, by using the liquid crystal alignment film, a liquid crystal display element having good afterimage characteristics and excellent display quality can be effectively manufactured.

Detailed Description

The present invention will be described in detail below. The following description of the constituent elements is sometimes made based on the representative embodiments and specific examples, but the present invention is not limited to such embodiments. In the present invention, the "liquid crystal aligning agent" is a liquid crystal aligning agent capable of imparting anisotropy by irradiation of polarized ultraviolet rays when the film is formed on a substrate, and is also referred to as "liquid crystal aligning agent" in the present specification, or as "liquid crystal aligning agent for photo-alignment". In the present invention, the term "tetracarboxylic acid derivative" means a tetracarboxylic dianhydride, a tetracarboxylic diester, or a tetracarboxylic diester dihalide. The tetracarboxylic acid diester and the tetracarboxylic acid diester dihalide are sometimes collectively referred to as derivatives of tetracarboxylic acid dianhydride. In the present invention, the diamine and dihydrazide are sometimes referred to as "diamines". The chemical formula in the present specification represents a bond.

< Liquid Crystal alignment agent for photo-alignment of the invention >

The liquid crystal aligning agent for photo-alignment of the present invention is characterized by comprising at least 2 polymers selected from the group consisting of a polymer (K) and a polymer (L) which are obtained by reacting a tetracarboxylic acid derivative with a diamine, wherein the polymer (K) comprises at least one tetracarboxylic acid derivative represented by the formula (I) and at least one diamine having a Boc structure as a raw material, and the polymer (L) does not comprise a tetracarboxylic acid derivative represented by the formula (I) and does not comprise a diamine having a Boc structure as a raw material. This polymer is sometimes referred to as the polymer of the present invention. In the present invention, the polyamic acid derivative refers to polyimide, partial polyimide, polyamic acid ester, polyamic acid-polyamide copolymer and polyamide imide.

< Kind of Polymer >

The polyamic acid and the polyamic acid derivative will be described in detail below.

Here, the polyamic acid is a polymer synthesized by polymerization reaction of tetracarboxylic dianhydride represented by formula (AN) and diamine represented by formula (DI), and has a structural unit represented by formula (PAA). When the liquid crystal alignment agent containing the polyamic acid is heated and fired in the step of forming the liquid crystal alignment film, the polyamic acid is imidized, and a polyimide liquid crystal alignment film having a structural unit represented by the formula (PI) can be formed.

In the formula (AN), the formula (PAA) and the formula (PI), X ¹ is a 4-valent organic group. In the formula (DI), the formula (PAA) and the formula (PI), X ² is a 2-valent organic group. For preferred ranges and specific examples of the 4-valent organic groups in X ¹, reference may be made to the corresponding structures of the tetracarboxylic dianhydrides described in the present specification. For a preferable range and specific examples of the 2-valent organic group in X ², reference may be made to the description of the corresponding structure of the diamine or dihydrazide described in the diamine column described in the present specification.

The polyamic acid derivative is a compound having properties changed by substituting a part of the polyamic acid with another atom or group of atoms, and particularly preferably has improved solubility in a solvent used for the liquid crystal aligning agent. Specific examples of such polyamic acid derivatives include 1) polyimide in which all amino groups and carboxyl groups of a polyamic acid have undergone a dehydrative ring closure reaction, 2) partially polyimide in which a dehydrative ring closure reaction has been partially performed, 3) polyamic acid ester in which a carboxyl group of a polyamic acid has been converted into an ester, 4) polyamic acid-polyamide copolymer in which a part of an acid dianhydride contained in a tetracarboxylic acid dianhydride compound has been replaced with an organic dicarboxylic acid and reacted, and 5) polyamideimide in which a part or all of the polyamic acid-polyamide copolymer has undergone a dehydrative ring closure reaction. Among these derivatives, for example, polyimide may be represented by the structural unit represented by the above formula (PI), and polyamic acid ester may be represented by the structural unit represented by the following formula (PAE).

In formula (PAE), X ¹ is a 4-valent organic group, X ² is a 2-valent organic group, and Y is independently an alkyl group. For a preferable range and specific examples of X ¹、X², the description of X ¹、X² in formula (PAA) can be referred to. In Y, a linear or branched alkyl group having 1 to 6 carbon atoms is preferable, and methyl, ethyl, propyl, isopropyl, butyl, isobutyl or tert-butyl is more preferable.

The tetracarboxylic dianhydride and the diamine used for the synthesis of the polyamic acid may be 1 or 2 or more.

In the case of producing the polyamide acid of the present invention into a polyimide as a polyamide acid derivative, the obtained polyamide acid solution is subjected to imidization reaction at a temperature of 20 to 150 ℃ together with an acid anhydride such as acetic anhydride, propionic anhydride, trifluoroacetic anhydride or the like as a dehydrating agent and a tertiary amine such as triethylamine, pyridine, collidine or the like as a dehydrating ring-closing catalyst, whereby a polyimide can be obtained. Alternatively, a polyimide may be obtained by precipitating a polyamic acid from the obtained polyamic acid solution using a large amount of a poor solvent (an alcoholic solvent such as methanol, ethanol, or isopropanol, or an ethylene glycol solvent), and subjecting the precipitated polyamic acid to imidization reaction in a solvent such as toluene or xylene together with the dehydrating agent and the dehydration ring-closure catalyst at a temperature of 20 to 150 ℃.

In the imidization reaction, the ratio of the dehydrating agent to the dehydration ring-closing catalyst is preferably 0.1 to 10 (molar ratio). The total amount of the dehydrating agent and the dehydrating ring-closing catalyst to be used is preferably 1.5 to 10 times by mol based on the total amount of the molar amount of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid. By adjusting the amount of the dehydrating agent, the catalyst, the reaction temperature and the reaction time used in the imidization reaction, the degree of imidization can be controlled, and thus, only a part of the polyamic acid can be imidized to obtain a part of polyimide. The polyimide thus obtained may be separated from the solvent used in the reaction and dissolved in another solvent to be used as a liquid crystal aligning agent, or may be used as a liquid crystal aligning agent without separation from the solvent.

The polyamic acid ester can be obtained by a method of synthesizing a polyamic acid by reacting with a hydroxyl group-containing compound, a halide, an epoxy group-containing compound, or the like, or a method of synthesizing a tetracarboxylic acid diester derived from a tetracarboxylic acid dianhydride or a tetracarboxylic acid diester dichloride by reacting with a diamine. The tetracarboxylic acid diester derived from the tetracarboxylic acid dianhydride can be obtained, for example, by ring-opening by reacting the tetracarboxylic acid dianhydride with 2 equivalents of alcohol, and the tetracarboxylic acid diester dichloride can be obtained by reacting the tetracarboxylic acid diester with 2 equivalents of a chlorinating agent (for example, thionyl chloride, etc.). The polyamic acid ester may have only a amic acid ester structure, or may be a partial ester in which the amic acid structure and the amic acid ester structure coexist.

The polyamic acid or derivative thereof of the present invention can be produced in the same manner as a known polyamic acid or derivative thereof used for forming a polyimide film. The total amount of the tetracarboxylic acid derivatives added is preferably 0.9 to 1.1 mol based on 1 mol of the total of diamines.

The liquid crystal aligning agent of the present invention may contain only 1 kind of these polyamic acid, polyamic acid ester, and polyimide obtained by imidizing these, or may contain 2 or more kinds.

The molecular weight of the polyamic acid or derivative thereof of the present invention is preferably 5000 to 500000, more preferably 5000 to 50000, in terms of weight average molecular weight (Mw) in terms of polystyrene. The molecular weight of the polyamic acid or derivative thereof can be determined by measurement using Gel Permeation Chromatography (GPC).

The polyamic acid or derivative thereof of the present invention can be confirmed by analyzing a solid component precipitated with a large amount of a poor solvent by IR (infrared spectroscopy) or NMR (nuclear magnetic resonance analysis). Further, the monomers used can be confirmed by analyzing an extract of a decomposition product of the polyamic acid or derivative thereof formed from an aqueous solution of a strong base such as KOH or NaOH with an organic solvent by GC (gas chromatography), HPLC (high performance liquid chromatography) or GC-MS (gas chromatography mass spectrometry).

< Tetracarboxylic acid derivative >

The polymer (K) of the present invention may contain a compound represented by the formula (I) as a raw material or may contain other tetracarboxylic acid derivatives. Specific examples of the compounds represented by the following formula (I) and other tetracarboxylic acid derivatives are described below.

< Compound represented by formula (I) >

The compound represented by the formula (I) used in the raw material of the polymer (K) of the present invention will be described.

In the formula (I), 1', 2 and 2' are bond, each independently bond to a hydroxyl group, a chlorine atom or an alkoxy group having 1 to 6 carbon atoms, and at least one of the group of 1 and 1 'and the group of 2 and 2' may bond to the same oxygen atom;

R ^b1、R^b2、R^b3 and R ^b4 are each independently a hydrogen atom or a methyl group, at least one of which is a methyl group.

Specific examples of the alkoxy group having 1 to 6 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy and tert-butoxy. Methoxy is preferred from the viewpoint of the easiness of imidization.

The formula (I) includes a form in which all of 4 bonding bonds are bonded to any one of a hydroxyl group, a chlorine atom, and an alkoxy group having 1 to 6 carbon atoms, a form in which any one of a group of 1 and 1 'and a group of 2 and 2' is bonded to the same oxygen atom, a form in which 2 bonding bonds of the remaining group are bonded to any one of a hydroxyl group, a chlorine atom, and an alkoxy group having 1 to 6 carbon atoms, and a form in which both a group of 1 and 1 'and a group of 2 and 2' are bonded to the same oxygen atom. Preferably, the form in which all of 4 bonding bonds are bonded to any one of a hydroxyl group, a chlorine atom, and an alkoxy group having 1 to 6 carbon atoms, and the form in which both of the group of 1 and 1 'and the group of 2 and 2' are bonded to the same oxygen atom.

From the viewpoint of obtaining a liquid crystal alignment film having high sensitivity, it is preferable that R ^b1 and R ^b4 are methyl groups, and R ^b2 and R ^b3 are hydrogen.

Preferred examples of the compound represented by the formula (I) are shown below.

In the polymer (K) of the present invention, by using the compound represented by the formula (I), a liquid crystal aligning agent which can form a liquid crystal alignment film having high liquid crystal alignment properties by photo-alignment treatment can be obtained. Among the compounds represented by the formula (I), the compounds represented by the formula (I-1) are preferably used.

In the polymer (K) of the present invention, the compound represented by the formula (I) is preferably used in an amount of 50 mol% or more, more preferably 80 mol% or more, still more preferably 100 mol% or more based on the total amount of the tetracarboxylic acid derivative used. A plurality of compounds represented by the formula (I) may be used in combination.

In the polymer (L) of the present invention, a liquid crystal aligning agent capable of forming a liquid crystal alignment film which suppresses a bright spot defect derived from a photodecomposition can be obtained by not using the compound represented by the formula (I).

< Tetracarboxylic acid derivative other than formula (I) >)

The tetracarboxylic acid derivatives other than the formula (I) are described below as tetracarboxylic dianhydrides represented by the formulas (AN-1) to (AN-9), (AN-10-1), (AN-10-2), (AN-11), (AN-12), (AN-15) and (AN-16-1) to (AN-16-19). These tetracarboxylic dianhydrides can also be derivatized to tetracarboxylic diesters, tetracarboxylic diester dichlorides, and used as starting materials for polymers.

[ Tetracarboxylic dianhydride represented by the formula (AN-1) ]

In the formula (AN-1), G ¹⁰ is a single bond, AN alkylene group having 1 to 12 carbon atoms, 1, 4-phenylene group, 1, 4-cyclohexylene group, or the formula (G10-1). R ¹¹ is independently a hydrogen atom or a methyl group.

In the formula (G10-1), X is independently a single bond, -O-, -S-, or-NR ¹-,R¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, n is independently an integer of 1 to 5, m is an integer of 1 to 3, and a group which forms an unfixed bonding position on any carbon atom of the ring represents a group capable of bonding to any one of the bondable carbons in the ring.

The tetracarboxylic dianhydride represented by the following formula (AN-1) is exemplified.

In the formulae (AN-1-2) and (AN-1-5), m is AN integer of 1 to 12 independently of each other.

[ Tetracarboxylic dianhydride represented by the formula (AN-2) ]

In the formula (AN-2), G ¹¹ is a single bond, AN alkylene group having 1 to 12 carbon atoms, a 1, 4-phenylene group or a 1, 4-cyclohexylene group. X ¹¹ is a single bond or-CH ₂-.G¹² is independently any of the following 3-valent groups.

When G ¹² is > N-, G ¹¹ is not a single bond and-CH ₂-、X¹¹ is not a single bond.

The tetracarboxylic dianhydride represented by the following formula (AN-2) is exemplified.

In the formula (AN-2-1), m is AN integer of 1 to 12.

[ Tetracarboxylic dianhydride represented by the formula (AN-3) ]

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

As examples of the tetracarboxylic dianhydride represented by the formula (AN-3), compounds represented by the following formulas (AN-3-1) and (AN-3-2) can be given.

[ Tetracarboxylic dianhydride represented by the formula (AN-4) ]

In the formula (AN-4), G ¹³ is a single bond 、-(CH₂)_m-、-O-、-S-、-C(CH₃)₂-、-SO₂-、-CO-、-C(CF₃)₂-、 or a 2-valent group represented by the following formula (G13-1), and m is AN integer of 1 to 12. Ring a ¹¹ is each independently a cyclohexane ring or a benzene ring. G ¹³ may be bonded to any position of ring a ¹¹.

In the formula (G13-1), G ^13a and G ^13b are each independently a 2-valent group represented by a single bond, -O-, -CONH-, or-NHCO-. The phenylene group is preferably a1, 4-phenylene group or a1, 3-phenylene group.

As AN example of the tetracarboxylic dianhydride represented by the formula (AN-4), compounds represented by the following formulas (AN-4-1) to (AN-4-31) are given.

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

[ Tetracarboxylic dianhydride represented by the formula (AN-5) ]

In formula (AN-5), R ¹¹ is independently a hydrogen atom or a methyl group. R ¹¹ in the benzene ring in two R ¹¹ is bonded to any one of the substitutable positions of the benzene ring.

As AN example of the tetracarboxylic dianhydride represented by the formula (AN-5), compounds represented by the following formulas (AN-5-1) to (AN-5-3) can be given.

[ Tetracarboxylic dianhydride represented by the formula (AN-6) ]

In formula (AN-6), X ¹¹ is independently a single bond or-CH ₂-.X¹² is-CH ₂-、-CH₂CH₂ -or-ch=ch-. n is 1 or 2. When n is 2, 2X ¹² may be the same as or different from each other.

As AN example of the tetracarboxylic dianhydride represented by the formula (AN-6), compounds represented by the following formulas (AN-6-1) to (AN-6-12) can be given.

[ Tetracarboxylic dianhydride represented by the formula (AN-7) ]

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

As examples of the tetracarboxylic dianhydride represented by the formula (AN-7), compounds represented by the following formulas (AN-7-1) and (AN-7-2) can be given.

[ Tetracarboxylic dianhydride represented by the formula (AN-8) ]

In the formula (AN-8), X ¹¹ is a single bond or-CH ₂-.R¹² is a hydrogen atom, methyl, ethyl or phenyl. Ring a ¹² is a cyclohexane ring or cyclohexene ring.

As examples of the tetracarboxylic dianhydride represented by the formula (AN-8), compounds represented by the following formulas (AN-8-1) and (AN-8-2) can be given.

[ Tetracarboxylic dianhydride represented by the formula (AN-9) ]

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

As AN example of the tetracarboxylic dianhydride represented by the formula (AN-9), compounds represented by the following formulas (AN-9-1) to (AN-9-3) are given.

[ Tetracarboxylic dianhydride represented by the formula (AN-10-1) and the formula (AN-10-2) ]

[ Tetracarboxylic dianhydride represented by the formula (AN-11) ]

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

As AN example of the tetracarboxylic dianhydride represented by the formula (AN-11), compounds represented by the following formulas (AN-11-1) to (AN-11-3) are given.

[ Tetracarboxylic dianhydride represented by the formula (AN-12) ]

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

As AN example of the tetracarboxylic dianhydride represented by the formula (AN-12), compounds represented by the following formulas (AN-12-1) to (AN-12-3) can be given.

[ Tetracarboxylic dianhydride represented by the formula (AN-15) ]

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

As AN example of the tetracarboxylic dianhydride represented by the formula (AN-15), compounds represented by the following formulas (AN-15-1) to (AN-15-3) can be given.

[ Tetracarboxylic dianhydride represented by the formula (AN-16-1) to the formula (AN-16-19) ]

The tetracarboxylic dianhydrides other than the above are compounds represented by the following formulas (AN-16-1) to (AN-16-19).

< Diamines >

The polymer (K) of the present invention may contain at least one of diamines having a Boc structure as a raw material, and may contain other diamines. Specific examples of diamines having a Boc structure and other diamines are described below.

H₂N—G²⁰-NH₂ (DI-1)

In the formula (DI-1), G ²⁰ is an alkylene group having 1 to 12 carbon atoms or a group represented by the formula (DI-1-a). When G ²⁰ is an alkylene group having 1 to 12 carbon atoms, at least 1 of the CH ₂ -groups may be reacted NH-or-O-substitutions but they are not adjacent, at least 1 hydrogen atom of-CH ₂ -may be substituted by a hydroxyl group or a methyl group.

In the formula (DI-1-a), v is an integer of 1 to 6 independently of each other.

In the formula (DI-3), the formula (DI-6) and the formula (DI-7), G ²¹ is independently a single bond 、-NH-、-NCH₃-、-O-、-S-、-S-S-、-SO₂-、-CO-、-COO-、-CONCH₃-、-CONH-、-C(CH₃)₂-、-C(CF₃)₂-、-(CH₂)_m-、-O-(CH₂)_m-O-、-N(CH₃)-(CH₂)_k-N(CH₃)-、-(O-C₂H₄)_m-O-、-O-CH₂-C(CF₃)₂-CH₂-O-、-O-CO-(CH₂)_m-CO-O-、-CO-O-(CH₂)_m-O-CO-、-(CH₂)_m-NH-(CH₂)_m-、-CO-(CH₂)_k-NH-(CH₂)_k-、-(NH-(CH₂)_m)_k-NH-、-CO-C₃H₆-(NH-C₃H₆)_n-CO-、 or-S- (CH ₂)_m -S-, m is independently an integer of 1 to 12, k is an integer of 1 to 5, and n is 1 or 2.

In the formula (DI-4), s is independently an integer of 0 to 2.

In the formula (DI-5), G ³³ is a single bond 、-NH-、-NCH₃-、-O-、-S-、-S-S-、-SO₂-、-CO-、-COO-、-CONCH₃-、-CONH-、-C(CH₃)₂-、-C(CF₃)₂-、-(CH₂)_m-、-O-(CH₂)_m-O-、-(O-C₂H₄)_m-O-、-O-CH₂-C(CF₃)₂-CH₂-O-、-O-CO-(CH₂)_m-CO-O-、-CO-O-(CH₂)_m-O-CO-、 or -S-(CH₂)_m-S-、-N(Boc)-(CH₂)_e-、-(CH₂)_m-N(Boc)-CONH-(CH₂)_m-、-(CH₂)_m-N(Boc)-(CH₂)_m-、 or a group represented by the following formula (DI-5-a) or the following formula (DI-5-b), m is independently an integer of 1 to 12, e is an integer of 2 to 10, and n is 1 or 2.Boc is tert-butoxycarbonyl.

In the formula (DI-5-a), q is an integer of 0 to 6 independently of each other. R ⁴⁴ is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

In the formula (DI-6) and the formula (DI-7), G ²² is independently a single bond, -O-, -S-, -CO-, -C (CH ₃)₂-、-C(CF₃)₂ -, or an alkylene group having 1 to 10 carbon atoms).

At least 1 hydrogen atom of the cyclohexane ring and the benzene ring in the formula (DI-2) to (DI-7) may be substituted with a fluorine atom, a chlorine atom, an alkyl group having 1 to 3 carbon atoms, a methoxy group, a hydroxyl group, a trifluoromethyl group, a carboxyl group, a carbamoyl group, a phenylamino group, a phenyl group or a benzyl group, and in the formula (DI-4), at least 1 hydrogen atom of the cyclohexane ring and the benzene ring may be substituted with 1 selected from the group represented by any one of the following formulas (DI-4-a) to (DI-4-i), and in the formula (DI-5), at least 1 hydrogen atom of the benzene ring may be substituted with NHBoc or N (Boc) ₂ when G ³³ is a single bond.

In the formula (DI-4-a) and the formula (DI-4-b), R ²⁰ is independently a hydrogen atom or a methyl group. In the formula (DI-4-f) and the formula (DI-4-g), m is an integer of 0 to 12, and Boc is tert-butoxycarbonyl.

In the formulae (DI-2) to (DI-7), the group in which the bonding position is not fixed to the carbon atom constituting the ring indicates that the bonding position of the ring is arbitrary.

In the formula (DI-11), r is 0 or 1. In the formulae (DI-8) to (DI-11), the bonding position of the amino group bonded to the ring is arbitrary.

In the formula (DI-12), R ²¹ and R ²² are each independently an alkyl group having 1 to 3 carbon atoms or a phenyl group, G ²³ is independently an alkylene group having 1 to 6 carbon atoms, a phenylene group or an alkyl-substituted phenylene group, and w is an integer of 1 to 10.

In the formula (DI-13), R ²³ is independently an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or a chlorine atom, and p and q are each independently integers of 0 to 4.

In the formula (DI-14), the ring B is a monocyclic heterocyclic aromatic group, R ²⁴ is a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group, an alkoxy group, an alkenyl group or an alkynyl group having 1 to 6 carbon atoms, and q is independently an integer of 0 to 4. When q is 2 or more, a plurality of R ²⁴ may be the same as or different from each other. In the formula (DI-15), the ring C is a heterocyclic aromatic group or a heterocyclic aliphatic group. In the formula (DI-16), G ²⁴ is a single bond, an alkylene group having 2 to 6 carbon atoms or a 1, 4-phenylene group, and r is 0 or 1.

In the formula (DI-17), R ²³ is independently an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or a chlorine atom, -NHBoc or-N (Boc) ₂, p is independently an integer of 0 to 4, R ²⁵ is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a tert-butoxycarbonyl group, and Z is a 2-valent group containing an alkylene group having 1 to 10 carbon atoms. Any position and any number of-CH ₂ -in the alkylene group having 1 to 10 carbon atoms may be substituted with-NH-or-CO-, but-NH-or-CO-are not adjacent.

Preferred examples of R ²⁵ are methyl or Boc, more preferably Boc. A preferable example of the 2-valent group containing an alkylene group having 1 to 10 carbon atoms in Z is- (CH ₂)_m-、-CO-(CH₂)₄ -CO-, and m is an integer of 1 to 10.

In the formulae (DI-13) to (DI-17), the group in which the bonding position is not fixed to the carbon atom constituting the ring indicates that the bonding position of the ring is arbitrary. The bonding position of the amino groups in the rings at both ends may be arbitrary, and para and meta are preferable, and para is more preferable.

In the formula (DIH-1), G ²⁵ is a single bond, an alkylene group having 1 to 20 carbon atoms, -CO-, -O-, -S-, -SO ₂-、-C(CH₃)₂ -, or-C (CF ₃)₂ -.

In the formula (DIH-2), the ring D is a cyclohexylene group, a phenylene group or a naphthylene group, and at least 1 hydrogen atom of the group may be substituted with a methyl group, an ethyl group or a phenyl group.

In the formula (DIH-3), the rings E are each independently cyclohexylene or phenylene, at least one hydrogen atom of which may be replaced by methyl, ethyl or phenyl. The 2 rings E may be the same as or different from each other. Y is a single bond, an alkylene group having 1 to 20 carbon atoms, -CO-, -O-, -S-, -SO ₂-、-C(CH₃)₂ -or-C (CF ₃)₂ - & lt- & gt in the formula (DIH-2) and the formula (DIH-3), and the bonding position of the-hydrazide group bonded to the ring is any position.

Examples of the diamine represented by the formula (DI-1) are shown in the following formulas (DI-1-1) to (DI-1-9).

In the formula (DI-1-7) and the formula (DI-1-8), k is an integer of 1 to 3 independently. In the formula (DI-1-9), v is an integer of 1 to 6 independently of each other.

Examples of the diamine represented by the formula (DI-2) to (DI-3) are represented by the following formulas (DI-2-1), (DI-2-2) and (DI-3-1) to (DI-3-3).

Examples of the diamine represented by the formula (DI-4) are shown by the following formulas (DI-4-1) to (DI-4-27).

In the formulae (DI-4-20) and (DI-4-21), m is an integer of 1 to 12 independently of each other.

An example of the diamine represented by the formula (DI-5) is shown below.

In the formula (DI-5-1), m is an integer of 1 to 12.

In the formula (DI-5-12) and the formula (DI-5-13), m is an integer of 1 to 12 independently from each other.

In the formula (DI-5-16), v is an integer of 1 to 6.

In the formula (DI-5-35) to the formula (DI-5-37), m is an integer of 1 to 12, in the formula (DI-5-38), k is an integer of 1 to 5, in the formula (DI-5-40), and n is an integer of 1 or 2.

In the formula (DI-5-44), e is an integer of 2 to 10, and R ⁴³ in the formula (DI-5-45) is a hydrogen atom, a (t-butoxycarbonyl) amino group or a bis (t-butoxycarbonyl) amino group.

Examples of the diamine represented by the formula (DI-6) are shown by the following formulas (DI-6-1) to (DI-6-7).

Examples of the diamine represented by the formula (DI-7) are shown by the following formulas (DI-7-1) to (DI-7-11).

In the formula (DI-7-3) and the formula (DI-7-4), m is an integer of 1 to 12, and n is 1 or 2.

Examples of the diamine represented by the formula (DI-8) are shown in the following formulas (DI-8-1) to (DI-8-4).

Examples of the diamine represented by the formula (DI-9) are shown by the following formulas (DI-9-1) to (DI-9-3).

Examples of the diamine represented by the formula (DI-10) are represented by the following formulas (DI-10-1) and (DI-10-2).

Examples of the diamine represented by the formula (DI-11) are shown by the following formulas (DI-11-1) to (DI-11-3).

Examples of the diamine represented by the formula (DI-12) are shown by the following formula (DI-12-1).

Examples of the diamine represented by the formula (DI-13) are shown by the following formulas (DI-13-1) to (DI-13-13).

Examples of the diamine represented by the formula (DI-14) are shown by the following formulas (DI-14-1) to (DI-14-9).

Examples of the diamine represented by the formula (DI-15) are shown by the following formulas (DI-15-1) to (DI-5-12).

Examples of the diamine represented by the formula (DI-16) are shown by the following formula (DI-16-1).

An example of the diamine represented by the formula (DI-17) is shown below.

In the formula (DI-17-1) and the formula (DI-17-5), k is an integer of 1 to 6 independently of each other. In the formulae (DI-17-2) to (DI-17-3), e is an integer of 1 to 10, and Boc is tert-butoxycarbonyl. In the formula (DI-17-4), each m is independently 1 or 2, and n is 1 or 2.

Examples of the compounds represented by any of the formulae (DIH-1) to (DIH-3) are represented by the following formulae (DIH-1-1), formula (DIH-1-2), formulae (DIH-2-1) to (DIH-2-3), and formulae (DIH-3-1) to (DIH-3-6).

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

In the polymer (K) of the present invention, the use of diamines having a Boc structure can improve the image retention characteristics. Among diamines having a Boc structure, the compound represented by the formula (DI-17-2) is preferably used. Of the compounds represented by the formula (DI-17-2), e=2 to 6 is more preferable, and e=2, 4 or 6 is even more preferable. In the polymer (K) of the present invention, the total amount of the compound represented by the formula (DI-17-2) is preferably 10 mol% or more based on the total amount of the diamines used. A plurality of compounds represented by the formula (DI-17-2) may be used in combination.

In the polymer (L) of the present invention, the residual image characteristics can be improved by not using diamines having a Boc structure.

In the polymer (L) of the present invention, the residual image characteristics can be improved by using at least one compound represented by the formula (DI-5) or the formula (DI-6).

In the formula (DI-5), G ³³ is a single bond 、-NCH₃-、-O-、-S-、-S-S-、-SO₂-、-CO-、-COO-、-CONCH₃-、-CONH-、-C(CH₃)₂-、-C(CF₃)₂-、-(CH₂)_m-、-O-(CH₂)_m-O-、-(O-C₂H₄)_m-O-、-O-CH₂-C(CF₃)₂-CH₂-O-、-O-CO-(CH₂)_m-CO-O-、-CO-O-(CH₂)_m-O-CO-、 or-S- (CH ₂)_m -S-, or a group represented by the following formula (DI-5-a) or the following formula (DI-5-b), and m is independently an integer of 1 to 12.

In the formula (DI-6) and the formula (DI-7), G ²¹ and G ²² are independently a single bond, -O-, -S-, -CO-, -C (CH ₃)₂-、-C(CF₃)₂ -, or an alkylene group having 1 to 10 carbon atoms).

Wherein, the preferably in formula (DI-5) G ³³ is-O-or-CH ₂ -; or a compound in which G ²¹ and G ²² are-O-in the formula (DI-6).

In the polymer (L) of the present invention, the total amount of the compound represented by the formula (DI-5) or (DI-6) is preferably 10 mol% or more based on the total amount of the diamines used. A plurality of compounds represented by the formula (DI-5) or the formula (DI-6) may be used in combination.

In the raw material composition used as a raw material for the polymer of the present invention, a part of the diamines may be substituted with at least 1 selected from the group consisting of monoamines and monoazides. The substitution ratio is preferably in a range in which the ratio of at least 1 selected from the group consisting of monoamines and monoazides to diamines is 40 mol% or less. Such substitution can cause termination of the polymerization reaction when the polyamic acid is formed, and further progress of the polymerization reaction can be suppressed. Therefore, by such substitution, the molecular weight of the obtained polymer (polyamic acid or derivative thereof) can be easily controlled, and for example, the coating property of the liquid crystal aligning agent can be improved without impairing the effect of the present invention. The diamine that may be substituted with monoamine or monoazide may be 1 or 2 or more, as long as the effect of the present invention is not impaired. Examples of the monoamine include aniline, 4-hydroxyaniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, p-aminophenyltrimethoxysilane, and 3-aminopropyltriethoxysilane.

In the case where the polymer of the present invention is a polyamic acid or derivative thereof, the raw material composition may further contain a monoisocyanate compound as a monomer. By including a monoisocyanate compound in the monomer, the terminal of the obtained polyamic acid or derivative thereof is modified, and the molecular weight is adjusted. By using the terminal-modified polyamic acid or derivative thereof, for example, the coating property of the liquid crystal aligning agent can be improved without impairing the effect of the present invention. From the above viewpoints, the content of the monoisocyanate compound in the monomer is preferably 1 to 10 mol% relative to the total amount of diamine and tetracarboxylic dianhydride in the monomer. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

The liquid crystal aligning agent of the present invention may be composed of 2 kinds of the polymer (K) and the polymer (L) of the present invention, or may be mixed with a polymer other than the polymer of the present invention. In the present specification, a liquid crystal aligning agent in which 2 or more kinds of the above polymers are mixed may be referred to as a mixed liquid crystal aligning agent.

The polymer (K) and the polymer (L) of the present invention are preferably polyamide acids from the viewpoint of solubility.

In the liquid crystal aligning agent of the present invention, the proportion of the polymer (K) in the total amount of the polymers is preferably 40% by weight or less from the viewpoint of the defective bright spots.

In addition, the liquid crystal aligning agent of the present invention may further contain a solvent from the viewpoints of coatability of the liquid crystal aligning agent and adjustment of the concentration of the polyamic acid or derivative thereof. The solvent is not particularly limited as long as it has an ability to dissolve the polymer component. The solvent is generally used in the production process and the use of the polymer component such as polyamic acid and soluble polyimide, and may be appropriately selected according to the purpose of use. The solvent may be 1 or a mixed solvent of 2 or more.

Examples of the solvent include a parent solvent of the polyamic acid or derivative thereof and other solvents for the purpose of improving coatability.

Examples of the aprotic polar organic solvent having a affinity for the polyamic acid or its derivative include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylimidazolidone, N-methylcaprolactam, N-methylpropionamide, N-dimethylacetamide, dimethylsulfoxide, N-dimethylformamide, N-diethylformamide, diethylacetamide, N-dimethylisobutyl amide, γ -butyrolactone, and γ -valerolactone. Among them, N-methyl-2-pyrrolidone, dimethyl imidazolidinone, gamma-butyrolactone or gamma-valerolactone is preferable.

Examples of other solvents for the purpose of improving the coatability and the like include ethylene glycol monoalkyl ethers such as ethylene glycol monobutyl ether and ethylene glycol mono-tertiary butyl ether, diethylene glycol monoalkyl ethers such as diethylene glycol monoethyl ether, diethylene glycol dialkyl ethers such as diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether and diethylene glycol butyl methyl ether. Examples of the ester compound include propylene glycol monoalkyl ether such as propylene glycol monomethyl ether and 1-butoxy-2-propanol, dipropylene glycol monoalkyl ether such as dipropylene glycol monomethyl ether, triethylene glycol monoalkyl ether, butyl cellosolve acetate, phenyl acetate, and ester compounds such as these acetates. Examples thereof include dialkyl malonates such as diethyl malonate, alkyl lactate, diisobutyl ketone, diacetone alcohol, 3-methyl-3-methoxybutanol, 4-methyl-2-pentanol, diisobutyl methanol, tetrahydronaphthalene, and isophorone.

Of these, diisobutyl ketone, 4-methyl-2-pentanol, diisobutyl methanol, ethylene glycol monobutyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol monoethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, 1-butoxy 2-propanol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether or butyl cellosolve acetate is preferred.

The concentration of the solid content in the liquid crystal aligning agent of the present invention is not particularly limited, and the optimum value may be selected according to various coating methods described below. In general, in order to suppress unevenness, pinholes, and the like at the time of coating, the amount is preferably 0.1 to 30% by weight, more preferably 1 to 10% by weight, relative to the weight of the varnish.

The viscosity of the liquid crystal aligning agent of the present invention varies depending on the method of coating, the concentration of the polyamic acid or derivative thereof, the kind of the polyamic acid or derivative thereof used, the kind and ratio of the solvent. For example, when the coating is performed by a printer, the thickness is 5 to 100 mPas (more preferably 10 to 80 mPas). When the thickness is 5 mPas or more, a sufficient film thickness is easily obtained, and when the thickness is 100 mPas or less, printing unevenness is easily suppressed. When the coating is performed by spin coating, it is preferably 5 to 200 mPas (more preferably 10 to 100 mPas). When the coating is performed by using an inkjet coating device, the thickness is preferably 5 to 50 mPas (more preferably 5 to 20 mPas). The viscosity of the liquid crystal aligning agent is measured by a rotational viscosity measurement method, for example, using a rotational viscometer (TVE-20L type viscometer manufactured by DONGMACHINESE Co., ltd.) (measurement temperature: 25 ℃).

The liquid crystal aligning agent of the present invention may further contain various additives. In order to improve various characteristics of the liquid crystal alignment film, various additives may be selectively used according to respective purposes. Examples are shown below.

< Alkenyl substituted Nadick imide Compound >

For example, the liquid crystal aligning agent of the present invention may further contain an alkenyl-substituted nadic imide compound for the purpose of stabilizing the electric characteristics of the liquid crystal display element for a long period of time. The alkenyl-substituted nadic imide compound may be used in an amount of 1 or 2 or more. In view of the above, the content of the alkenyl-substituted nadic imide compound is preferably 1 to 50% by weight, more preferably 1 to 30% by weight, and even more preferably 1 to 20% by weight, relative to the polyamic acid or derivative thereof. The alkenyl-substituted nadic imide compound is preferably a compound that can be dissolved in a solvent in which the polyamic acid or derivative thereof used in the present invention is dissolved. Preferred examples of the alkenyl-substituted nadic imide compound include alkenyl-substituted nadic imide compounds disclosed in japanese patent laid-open publication No. 2008-096979, japanese patent laid-open publication No. 2009-109987, and japanese patent laid-open publication No. 2013-242526. Particularly preferred alkenyl-substituted nadic imide compounds include bis {4- (allylbicyclo [2.2.1] hept-5-ene-2, 3-dicarboximide) phenyl } methane, N '-m-xylyl-bis (allylbicyclo [2.2.1] hept-5-ene-2, 3-dicarboximide) or N, N' -hexamethylene-bis (allylbicyclo [2.2.1] hept-5-ene-2, 3-dicarboximide).

< Compound having radically polymerizable unsaturated double bond >

For example, the liquid crystal aligning agent of the present invention may further contain a compound having a radical polymerizable unsaturated double bond for the purpose of stabilizing the electrical characteristics of the liquid crystal display element for a long period of time. The compound having a radical polymerizable unsaturated double bond may be 1 compound or 2 or more compounds. In addition, the alkenyl-substituted nadic imide compound is not included in the compound having a radical polymerizable unsaturated double bond. Examples of the compound having a radical polymerizable unsaturated double bond include, as preferable compounds, N ' -methylenebisacrylamide, N ' -dihydroxyethylene-bisacrylamide, ethylenebisacrylate, 4' -methylenebis (N, N-dihydroxyethyleneacryiamine), triallylcyanurate, and compounds having a radical polymerizable unsaturated double bond disclosed in Japanese patent application laid-open No. 2009-109987, japanese patent application laid-open No. 2013-242526, international publication No. 2014/119682, and International publication No. 2015/152014. From the above-mentioned object, the content of the compound having a radical polymerizable unsaturated double bond is preferably 1 to 50% by weight, more preferably 1 to 30% by weight, relative to the polyamic acid or derivative thereof.

< Oxazine Compound >

For example, the liquid crystal aligning agent of the present invention may further contain an oxazine compound for the purpose of stabilizing the electrical characteristics in the liquid crystal display element for a long period of time. The oxazine compound may be 1 compound or 2 or more compounds. From the above-mentioned object, the content of the oxazine compound is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and still more preferably 1 to 20% by weight, relative to the polyamic acid or derivative thereof.

The oxazine compound is soluble in a solvent for dissolving the polyamic acid or derivative thereof, and an oxazine compound having ring-opening polymerization is preferable. Preferable oxazine compounds include oxazine compounds represented by the formula (OX-3-1), the formula (OX-3-9) and the formula (OX-3-10), and oxazine compounds disclosed in Japanese patent application laid-open No. 2007-286597 and Japanese patent application laid-open No. 2013-242526.

< Oxazoline Compound >

For example, the liquid crystal aligning agent of the present invention may further contain an oxazoline compound for the purpose of stabilizing the electrical characteristics in the liquid crystal display element for a long period of time. The oxazoline compound is a compound having an oxazoline structure. The oxazoline compound may be 1 compound or 2 or more compounds. From the above-mentioned object, the content of the oxazoline compound is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and still more preferably 1 to 20% by weight, relative to the polyamic acid or derivative thereof. As a preferred oxazoline compound, there is mentioned an oxazoline compound disclosed in Japanese patent application laid-open No. 2010-054872 and Japanese patent application laid-open No. 2013-242526. More preferably, 1, 3-bis (4, 5-dihydro-2-oxazolyl) benzene is exemplified.

< Epoxy Compound >

For example, the liquid crystal aligning agent of the present invention may further contain an epoxy compound from the viewpoint of stabilizing the electrical characteristics in the liquid crystal display element for a long period of time, improving the hardness of the film, or improving the adhesion with the sealant. The epoxy compound may be 1 kind of compound or 2 or more kinds of compounds. From the above-mentioned object, the content of the epoxy compound is preferably 0.1 to 50% by weight, more preferably 1 to 20% by weight, and even more preferably 1 to 10% by weight, relative to the polyamic acid or derivative thereof.

As the epoxy compound, various compounds having 1 or 2 or more epoxy rings in the molecule can be used.

For the purpose of improving the hardness of the film or the adhesion to the sealant, a compound having 2 or more epoxy rings in the molecule is preferable, and a compound having 3 or 4 epoxy rings is more preferable.

Examples of the epoxy compound include those disclosed in Japanese patent application laid-open No. 2009-175715, japanese patent application laid-open No. 2013-242526, japanese patent application laid-open No. 2016-170409 and International publication No. 2017/217413. Preferred epoxy compounds include N, N, N ', N ' -tetraglycidyl-4, 4' -diaminodiphenylmethane, 3-glycidoxypropyl trimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltriethoxysilane, (3, 3', 4' -diepoxy) dicyclohexyl, 1, 4-butanediol glycidyl ether, tris (2, 3-epoxypropyl) isocyanurate, 1, 3-bis (N, N-diglycidyl aminomethyl) cyclohexane, and N, N, N ', N ' -tetraglycidyl-m-xylylenediamine. More preferably, 3-glycidoxypropyl trimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyl trimethoxysilane, and 2- (3, 4-epoxycyclohexyl) ethyl triethoxysilane are exemplified. In addition to the above, an oligomer or polymer having an epoxy ring may be added. As the oligomer and polymer having an epoxy ring, those disclosed in Japanese patent application laid-open No. 2013-242526 can be used.

< Silane Compound >

For example, the liquid crystal aligning agent of the present invention may further contain a silane compound for the purpose of improving adhesion to a substrate and a sealant. From the above-mentioned object, the content of the silane compound is preferably 0.1 to 30% by weight, more preferably 0.5 to 20% by weight, and even more preferably 0.5 to 10% by weight, relative to the polyamic acid or derivative thereof.

As the silane compound, a silane coupling agent disclosed in japanese patent application laid-open publication No. 2013-242526, japanese patent application laid-open publication No. 2015-212807, japanese patent application laid-open publication No. 2018-173545, and international publication No. 2018/181566 can be used. Preferable silane coupling agents include 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyl trimethoxysilane, p-aminophenyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-glycidoxypropyl methyl diethoxysilane, 3-isocyanatopropyl triethoxysilane, and 3-ureidopropyl triethoxysilane.

In addition to the above-described additives, a compound having a cyclic carbonate group, a compound having a hydroxyalkylamide moiety, or a hydroxyl group may be added for the purpose of improving the strength of a liquid crystal alignment film or for the purpose of stabilizing the electrical characteristics in a liquid crystal display element for a long period of time. Specific examples of the compound include those disclosed in Japanese patent application laid-open No. 2016-118753 and International publication No. 2017/110976. Preferable examples of the compound include the following formulae (HD-1) to (HD-4). These compounds are preferably 0.5 to 50% by weight, more preferably 1 to 30% by weight, and even more preferably 1 to 10% by weight, relative to the polyamic acid or derivative thereof.

In addition, when it is necessary to improve the antistatic property, an antistatic agent may be used, and when imidization is performed at a low temperature, an imidization catalyst may be used. As the imidization catalyst, there may be mentioned an imidization catalyst disclosed in Japanese patent application laid-open No. 2013-242526.

< Liquid Crystal alignment film >

The liquid crystal alignment film of the present invention is a film formed by heating the coating film of the liquid crystal alignment agent of the present invention. The liquid crystal alignment film of the present invention can be obtained by a usual method for producing a liquid crystal alignment film from a liquid crystal alignment agent. For example, the liquid crystal alignment film of the present invention can be obtained by a step of forming a coating film of the liquid crystal alignment agent of the present invention, a step of heat-drying, and a step of heat-firing. The liquid crystal alignment film of the present invention is subjected to a treatment for imparting anisotropy. As the treatment, friction treatment may be performed to impart anisotropy, but it is preferable to impart anisotropy by light irradiation.

Hereinafter, a method for forming a liquid crystal alignment film of the liquid crystal alignment agent for photo-alignment of the present invention will be described.

The coating film can be formed by coating the liquid crystal alignment agent of the present invention on a substrate in a liquid crystal display element in the same manner as in the production of a normal liquid crystal alignment film. Examples of the substrate include substrates such as glass, silicon nitride, acrylic, polycarbonate, and polyimide, which may be provided with electrodes such as ITO (Indium Tin Oxide), IZO (In ₂O₃ -ZnO, indium Oxide doped zinc Oxide), IGZO (In-Ga-ZnO ₄, indium gallium zinc Oxide) electrodes, and color filters.

As a method of applying a liquid crystal aligning agent to a substrate, a spin method, a printing method, a dipping method, a dropping method, an inkjet method, and the like are generally known. These methods are equally applicable in the present invention.

In general, a method of performing a heat treatment in an oven or an infrared oven, a method of performing a heat treatment on a heating plate, and the like are known in the heat drying step. The heat drying step is preferably performed at a temperature within a range where the solvent can evaporate, and more preferably at a temperature lower than the temperature in the heat firing step. Specifically, the heating and drying temperature is preferably in the range of 30 ℃ to 150 ℃, and more preferably in the range of 50 ℃ to 120 ℃.

The heating and firing step may be performed under conditions required for imidization of the polyamic acid or derivative thereof. The firing of the coating film is generally known as a method of heat-treating in an oven or an infrared oven, a method of heat-treating on a heating plate, or the like. These methods are equally applicable to the present invention. The temperature is usually preferably about 90 to 300 ℃, more preferably 120 to 280 ℃, and even more preferably 150 to 250 ℃. The firing time is not particularly limited, and is usually 1 minute to 2 hours, and is usually 10 minutes to 40 minutes.

The heating may be performed in several times, or may be performed by changing the temperature at this time.

In order to orient the liquid crystal in one direction with respect to the horizontal and/or vertical directions, a known photo-alignment method can be preferably used as a means for imparting anisotropy to the liquid crystal alignment film.

As the light used in the light irradiation step in the photo-alignment method, for example, ultraviolet or visible light including light having a wavelength of 150 to 800nm may be used. The light is not particularly limited as long as it can impart liquid crystal alignment ability to the film, and if it is desired to make the liquid crystal exhibit strong alignment regulating force, polarized light is preferable, and linearly polarized light is further preferable.

The wavelength of the polarized light in the light irradiation step is preferably 150 to 400nm, more preferably 200 to 400nm, and even more preferably 200 to 300nm. The irradiation amount of the polarized light is preferably 0.001 to 10J/cm ², more preferably 0.1 to 5J/cm ². The irradiation angle of the polarized light on the film surface is not particularly limited, and in the case where it is desired to exhibit a strong alignment regulating force on the liquid crystal, it is preferable that the irradiation angle be as perpendicular as possible to the film surface from the viewpoint of shortening the alignment treatment time. In addition, the liquid crystal alignment film of the present invention can align liquid crystals in a direction perpendicular to the polarization direction of linearly polarized light by irradiating the linearly polarized light.

The light source used in the light irradiation step may be, without limitation, an ultra-high pressure mercury lamp, a low pressure mercury lamp, a Deep ultraviolet (Deep UV) lamp, a halogen lamp, a metal halide lamp, a high power metal halide lamp, a xenon lamp, a mercury-xenon lamp, an excimer lamp, a KrF (krypton fluoride) excimer laser, a fluorescent lamp, an LED (LIGHT EMITTING Diode) lamp, a sodium lamp, a microwave excitation electrodeless lamp, or the like.

In order to improve the liquid crystal alignment ability of the liquid crystal alignment film, light irradiation may be performed while heating the liquid crystal alignment film. In this case, the heating temperature is preferably in the range of 50 ℃ to 250 ℃.

The light irradiation step may be performed after the heat drying step or after the heat firing step, and is preferably performed after the heat firing step. The heat drying step may be performed simultaneously with the heating drying step.

The liquid crystal alignment film of the present invention is preferably additionally heated after the light irradiation step. The heating temperature is preferably 150 to 300 ℃, more preferably 150 to 250 ℃, and even more preferably 200 to 250 ℃ at the same temperature or higher than the temperature of the heating and firing step. The additional heating time is preferably 5 minutes to 2 hours, more preferably 5 to 60 minutes, and still more preferably 5 to 30 minutes.

The washing step may be provided after the light irradiation step or after the additional heating step. Specifically, the liquid crystal alignment film is immersed in a solvent. The temperature at the time of impregnation is preferably 10to 80 ℃, more preferably 20 to 50 ℃. In addition, ultrasonic treatment is also preferable. The treatment time is preferably 1 minute to 1 hour, more preferably 1 minute to 30 minutes. The solvent to be used is not particularly limited as long as it is a solvent that dissolves a decomposed product formed from the liquid crystal alignment film by irradiation with ultraviolet rays, and examples thereof include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, and the like. Among them, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate is preferable from the viewpoint of versatility and safety. After impregnation, heating or rinsing is preferably carried out. Or both may be performed. The heating temperature is preferably 150 to 300 ℃, more preferably 200 to 230 ℃. The heating time is preferably 10 seconds to 30 minutes, more preferably 1 to 10 minutes. The solvent used for the flushing is preferably a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone or methyl ethyl ketone.

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

The liquid crystal alignment film of the present invention can be suitably used for alignment control of a liquid crystal composition in a liquid crystal display element. In addition to the alignment application of the liquid crystal composition of the liquid crystal display element, the composition can be used for the alignment control of the liquid crystal material in all other element liquid crystal elements such as a liquid crystal antenna, a dimming window, an optical compensation material, a variable phase shifter and the like.

< Liquid Crystal display element >

Next, a liquid crystal display element of the present invention will be described. The liquid crystal display element of the present invention is characterized by having the liquid crystal alignment film of the present invention, and can realize high display quality having excellent afterimage characteristics and suppression of bright point defects from photodecomposition products.

The liquid crystal display element of the present invention will be described in detail. The present invention provides a liquid crystal display element comprising a pair of substrates disposed to face each other, electrodes formed on one or both of the facing surfaces of the pair of substrates, a liquid crystal alignment film formed on the facing surfaces of the pair of substrates, a liquid crystal layer formed between the pair of substrates, and a pair of polarizing films, a backlight, and a driving device disposed so as to sandwich the pair of substrates, wherein the liquid crystal alignment film is composed of the liquid crystal alignment film of the present invention.

The electrode is not particularly limited as long as it is formed on one surface of the substrate. Examples of such electrodes include ITO and metal vapor deposited films. The electrode may be formed on the entire surface of one surface of the substrate, or may be formed in a desired shape, for example, by patterning. Examples of the desired shape of the electrode include a comb-shaped structure and a zigzag structure. The electrode may be formed on one substrate or on both substrates of the pair of substrates. The formation mode of the electrode varies depending on the type of the liquid crystal display element, and is, for example, in the case of an IPS type liquid crystal display element or an FFS type liquid crystal display element (in-plane switching type liquid crystal display element), the electrode is disposed on one of the pair of substrates, and in the case of the other liquid crystal display element, the electrode is disposed on both of the pair of substrates. The liquid crystal alignment film is formed on the substrate or electrode.

The liquid crystal layer is formed by sandwiching a liquid crystal composition between the pair of substrates facing each other on which the liquid crystal alignment film is formed. In the formation of the liquid crystal layer, spacers having appropriate intervals may be formed using fine particles, resin sheets, or the like interposed between the pair of substrates as needed.

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

In the vacuum injection method, a gap (cell gap) is provided so that the liquid crystal alignment film faces, and an injection port of liquid crystal remains, and a sealing agent is printed and bonded to a substrate. After filling liquid crystal is injected into a cell gap partitioned by a substrate surface and a sealant by vacuum pressure difference, the injection port is sealed, and a liquid crystal display element is manufactured.

In the ODF method, a sealant is applied to the outer Zhou Yinshua of one liquid crystal alignment film surface of a pair of substrates, and crystals are dropped into the inner region of the sealant, and then the other substrate is bonded so that the liquid crystal alignment film surfaces face each other. Then, the liquid crystal is spread over the entire surface of the substrate, and then the entire surface of the substrate is irradiated with ultraviolet light to cure the sealant, thereby manufacturing a liquid crystal display element.

A thermosetting type sealant is known as a sealant for bonding substrates, in addition to UV (Ultraviolet) curing type sealant. The sealing agent may be printed by, for example, screen printing.

The liquid crystal composition is not particularly limited, and various liquid crystal compositions having positive or negative dielectric anisotropy may be used. Among preferred liquid crystal compositions having positive dielectric anisotropy, there are those disclosed in Japanese patent application No. 3086228, japanese patent No. 2635435, japanese patent application No. Hei 5-501735, japanese patent application No. Hei 8-157826, japanese patent application No. Hei 8-231960, japanese patent application No. Hei 9-241644 (EP 885272A 1), japanese patent application No. Hei 9-302346 (EP 806466A 2), japanese patent application No. Hei 8-199168 (EP 722998A 1), japanese patent application No. Hei 9-235552, japanese patent application No. Hei 9-255956, japanese patent application No. Hei 9-241643 (EP 885271A 1), japanese patent application No. Hei 10-204016 (EP 844229A 1), japanese patent application No. Hei 10-204436, japanese patent application No. Hei 10-231482, japanese patent application No. 2000-7040, japanese patent application No. 2001-48822, and the like.

As a preferable example of the liquid crystal composition having negative dielectric anisotropy, examples thereof include Japanese patent application laid-open No. 57-114532, japanese patent application laid-open No. 2-4725, japanese patent application laid-open No. 4-224885, japanese patent application laid-open No. 8-40953, japanese patent application laid-open No. 8-104869, japanese patent application laid-open No. 10-168076, japanese patent application laid-open No. 10-168453, japanese patent application laid-open No. 10-236989, japanese patent application laid-open No. 10-236990, japanese patent application laid-open No. 10-236992, japanese patent application laid-open No. 10-236993, japanese patent application laid-open No. 10-236994, japanese patent application laid-open No. 10-237000, japanese patent application laid-open No. 10-237004, japanese patent application laid-open No. 10-237024, japanese patent application laid-open No. 10-236989, japanese patent application laid-open No. 10-3662, japanese patent application laid-open No. 10-237000 Japanese patent application laid-open No. 10-237035, japanese patent application laid-open No. 10-237075, japanese patent application laid-open No. 10-237076, japanese patent application laid-open No. 10-237448 (EP 967261A 1), japanese patent application laid-open No. 10-287874, japanese patent application laid-open No. 10-287875, japanese patent application laid-open No. 10-291945, japanese patent application laid-open No. 11-029581, japanese patent application laid-open No. 11-080049, japanese patent application laid-open No. 2000-256307, japanese patent application laid-open No. 2001-019965, japanese patent application laid-open No. 2001-072626, japanese patent application laid-open No. 2001-192657, japanese patent application laid-open No. 2010-037428, japanese patent application laid-open No. 2011/024566, japanese patent application laid-open No. 2010/072370, liquid crystal compositions disclosed in japanese patent application laid-open publication No. 2010-537010, japanese patent application laid-open publication No. 2012-077201, japanese patent application laid-open publication No. 2009-084362, and the like.

1 Or more optically active compounds may be added to a liquid crystal composition having positive or negative dielectric anisotropy.

In addition, for example, from the viewpoint of improving the alignment property, the liquid crystal composition used in the liquid crystal display element of the present invention may further contain additives. Such additives are photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, pigments, defoamers, polymerization initiators, polymerization inhibitors, and the like. Preferred examples of the photopolymerizable monomer, optically active compound, antioxidant, ultraviolet absorber, pigment, defoamer, polymerization initiator and polymerization inhibitor include those disclosed in International publication No. 2015/146330.

To suit the liquid crystal display element of the PSA (polymer sustained alignment) mode, the polymer is stable oriented, a polymerizable compound may be mixed into the liquid crystal composition. Preferred examples of the polymerizable compound are compounds having a polymerizable group such as acrylic acid ester, methacrylic acid ester, vinyl compound, vinyloxy compound, propenyl ether, epoxy compound (ethylene oxide, oxetane), vinyl ketone and the like. Preferred compounds include those disclosed in International publication No. 2015/146330.

Examples (example)

The present invention will be described below with reference to examples. In addition, the evaluation methods and compounds used in the examples are as follows.

In the synthesis example, the viscosity of the polymer solution was measured at 25℃using a rotary viscometer (TVE-20L type manufactured by DONGCHINESE Co., ltd.) with a sample size of 1.1 mL.

< Imidization Rate of polyimide >

The polyimide solution was poured into pure water, and the obtained precipitate was dried under reduced pressure at room temperature, and then dissolved in deuterated dimethyl sulfoxide, and 1H-NMR was measured at room temperature based on tetramethylsilane. From the 1H-NMR spectrum obtained, the imidization rate [% ] was obtained by the following formula (1).

Imidization ratio [% ] = (1- α×a1/A2) ×100..(1)

In the formula (1), A1 is a peak area of protons derived from NH groups occurring in the vicinity of a chemical shift of 10ppm, A2 is a peak area of other protons, and α is a number ratio of other protons to 1 proton of NH groups in a precursor (polyamic acid) of the polymer.

< Tetracarboxylic acid derivative >

< Diamine >

< Additive >

< Solvent >

NMP N-methyl-2-pyrrolidone

GBL gamma-butyrolactone

BC butyl cellosolve (ethylene glycol monobutyl ether)

Synthesis of varnish

Synthesis example 1

Synthesis of varnish A1

Into a 100mL 3-necked flask equipped with a stirring blade and a nitrogen inlet tube, 0.48g of the compound represented by the formula (D-10) and 3.53g of the compound represented by the formula (D-15) were charged, and 44.0g of NMP was added and stirred. To this solution, 1.99g of the compound represented by the formula (T-3) was added under a nitrogen atmosphere and stirred at room temperature for 12 hours. To this, 50.0g of GBL and 10.0g of BC were added, and the solution was heated and stirred at 60℃until the viscosity of the polymer of the solute reached the desired viscosity, to obtain a polyamic acid solution having a solute viscosity of about 30 mPas and a resin component concentration (solid component concentration) of 6 wt%, namely varnish A1.

Synthesis examples 2 to 10 and 13 to 19

Synthesis of varnishes A2 to A10 and varnishes B1 to 7

Varnishes A2 to A10 and B1 to 7, which were polyamide acid solutions having a solid content concentration of 6% by weight and a viscosity of about 30 mPas, were synthesized in the same manner as in Synthesis example 1, except that the compounds used as diamines and tetracarboxylic dianhydrides were changed as shown in tables 1 and 2. The numbers in brackets indicate weight and blank indicates that no compound corresponding to that column is used.

Synthesis example 11

Synthesis of varnish A11

Into a 100mL 3-necked flask equipped with a stirring blade and a nitrogen inlet tube, 0.73g of the compound represented by the formula (D-7), 1.55g of the compound represented by the formula (D-10) and 1.14g of the compound represented by the formula (D-15) were charged, and 44.0g of NMP was added and stirred. To this solution, 2.57g of the compound represented by the formula (T-3) was added under a nitrogen atmosphere and stirred at room temperature for 12 hours. To this solution, 0.91g of pyridine and 3.52g of acetic anhydride were added, and the mixture was heated at 60℃for 4 hours to carry out a dehydration ring-closure reaction. After the dehydration ring-closure reaction, the solvent in the system was replaced with a solvent so that the new NMP became 44.0g, to which was added GBL 50.0g and BC 10.0g, and the solution was heated and stirred at 60℃until the viscosity of the polymer of the solute reached the desired viscosity, to obtain varnish A11 as a polyimide solution having a solute viscosity of about 30 mPas, a resin component concentration (solid component concentration) of 6 wt% and an imidization ratio of about 60%.

Synthesis example 12

Synthesis of varnish A12

Into a 100mL 3-necked flask equipped with a stirring blade and a nitrogen inlet tube, 1.08g of the compound represented by the formula (D-8), 0.46g of the compound represented by the formula (D-9) and 1.35g of the compound represented by the formula (D-14) were charged, and 44.0g of NMP was added and stirred. To this solution, 1.84g of pyridine and 3.11g of the compound represented by the formula (T-4) were added under a nitrogen atmosphere, and the mixture was stirred at room temperature for 12 hours. The solution was poured into pure water while stirring, and the white precipitate was filtered. Then, washing with isopropyl alcohol 5 times, and drying were performed, whereby a polymer powder was obtained. To 3.0g of the polymer powder, 22.0g of NMP, 25.0g of GBL and 5.0g of BC were added, and the solution was heated and stirred at 60℃until the viscosity of the polymer of the solute reached the desired viscosity, to obtain a polyamic acid ester solution having a solute viscosity of about 30 mPas and a resin component concentration (solid component concentration) of 6 wt%, namely varnish A12.

TABLE 1

TABLE 2

Adjustment of varnish

Example 1

The varnish A1 and the varnish B1 were mixed at a weight ratio of 1:9, diluted with an NMP/GBL/BC mixed solution (NMP/GBL/bc=4/5/1 weight ratio) so that the solid content concentration became 4 weight%, stirred, and then filtered through a filter having a pore size of 0.2 μm to prepare a liquid crystal aligning agent 1. The prepared liquid crystal aligning agent was coated on the glass substrate with FFS electrode and the glass substrate with column spacer by spin coating. After the coating, the substrate was heated at 60 ℃ for 80 seconds to evaporate the solvent, and then baked at 230 ℃ for 30 minutes to form a liquid crystal alignment film. A high-pressure mercury lamp (manufactured by oxtail motor (ltd)) was used to irradiate the substrate with linearly polarized light of ultraviolet rays from the vertical direction through a polarizing plate having a polarization band of 230nm to 310 nm. At this time, the exposure energy was measured by using a UIT-150 (light receiver: UVD-S254) which is a UV-cumulative light meter manufactured by Niuwei Motor, inc., and the exposure time of the linearly polarized light was adjusted so that the "standard exposure" became 0.5.+ -. 0.05J/cm ² at a wavelength of 254 nm. Then, additional heating was performed at 230 ℃ for 30 minutes.

Next, the two substrates on which the liquid crystal alignment films are formed are placed in opposition to the liquid crystal alignment film-formed surface, and a gap for injecting a liquid crystal composition is provided between the opposing liquid crystal alignment films and bonded. At this time, the polarization directions of the linearly polarized light irradiated to the respective liquid crystal alignment films are made parallel. The negative liquid crystal composition A was injected into the cell to prepare a liquid crystal cell (liquid crystal display element) having a cell thickness of 4. Mu.m.

< Negative liquid Crystal composition A >

(Physical Property values)

The phase transition temperature NI is 75.7 ℃, the dielectric constant anisotropy delta epsilon is-4.1, the refractive index anisotropy delta n is 0.101, and the viscosity eta is 14.5 mPa.s.

< Evaluation of bright spots >

After the obtained liquid crystal cell was observed for a bright spot by a microscope, the liquid crystal cell was stored in a clean room at 25 ℃ for 14 days. Then, the same spot was observed again with a microscope, and the number of increased spots was evaluated as good for the case of 5 or less spots and as bad for the case of 6 or more spots.

< Evaluation of AC (ALTERNATING CURRENT ) afterimage >

The AC afterimage was measured according to the method described in WO 2000/43833. Specifically, the luminance-voltage characteristic (B-V characteristic) of the liquid crystal cell thus produced was measured and used as the luminance-voltage characteristic before stress application, B (before). Subsequently, after applying an alternating current of 4.5V and 30Hz for 20 minutes to the liquid crystal cell, the luminance-voltage characteristics (B-V characteristics) were measured again. This was used as the luminance-voltage characteristic after stress application, B (later). Here, as characteristic values of B (front) and B (rear), the luminance change rate Δb (%) was obtained by the following formula using the luminance at the voltage of 1.3V of each luminance-voltage characteristic measured. The smaller the value of Δb (%) is, the more favorable the generation of an AC afterimage, that is, the afterimage characteristics can be suppressed. If Δb is less than 3%, it is evaluated as "good", and if Δb is 3% or more, it is evaluated as "bad".

Δb (%) = { [ B (back) -B (front) ]/B (front) } ×100

< Evaluation of solubility >

After the liquid crystal alignment agent was stored at-25 ℃ for 2 weeks, the presence or absence of precipitation of the solid component was confirmed. The evaluation of the precipitate was not confirmed visually as good, and the evaluation of the precipitate was confirmed as bad.

Examples 2 to 4 and comparative examples 1 to 7

Liquid crystal aligning agents 2 to 4 and comparative aligning agents 1 to 7 were prepared in the same manner as in example 1, except that the varnishes shown in table 3 were used instead of varnish A1 and varnish B1 and the mixing ratio shown in table 3 was changed. Using the prepared liquid crystal aligning agent, evaluation of bright point, AC afterimage and solubility was performed in the same manner as in example 1. The varnish, mixing ratio and results used are shown in table 3 together with example 1.

Example 5

Varnish A5 and varnish B5 were mixed at a weight ratio of 3:7, and diluted with an NMP/GBL/BC mixed solution (NMP/GBL/bc=4/5/1 weight ratio) so that the solid content concentration became 4 weight%. To this solution, a compound represented by the formula (Ad-1) was added in an amount of 2% by weight based on the amount of solid components in the solution, and after stirring at room temperature for 2 hours, the mixture was filtered through a filter having a pore size of 0.2. Mu.m, to prepare a liquid crystal aligning agent 5. Evaluation of bright spots, AC afterimages, and solubility were performed in the same manner as in example 1, except for the adjustment method of the liquid crystal aligning agent. The evaluation results are shown in table 3.

Examples 6 to 8

Liquid crystal aligning agents 6 to 8 were prepared in the same manner as in example 5 except that the varnish and additives shown in table 3 were used instead of the varnish A5 and the varnish B5 and the mixing ratio shown in table 3 was changed. Using the prepared liquid crystal aligning agent, evaluation of bright point, AC afterimage and solubility was performed in the same manner as in example 1. The varnish, mixing ratio and results used are shown in table 3.

TABLE 3

In examples 1 to 8, the bright point evaluation, the AC afterimage and the solubility were all good results. On the other hand, in comparative example 1, the bright point evaluation was poor, in comparative examples 2 to 5, the AC afterimage was poor, and in comparative examples 6 to 7, the solubility was poor.

Industrial applicability

When the liquid crystal aligning agent for photo-alignment of the present invention is used, a liquid crystal alignment film having excellent display quality and capable of forming a liquid crystal display element having excellent residual image characteristics and suppressed bright point defects due to photodecomposition can be produced. The liquid crystal aligning agent for photo-alignment of the present invention has high solubility and is suitable for use in a transverse electric field type liquid crystal display element.

Claims (13)

1. A liquid crystal aligning agent comprising a polymer (K) and a polymer (L) which are obtained by reacting a tetracarboxylic acid derivative with a diamine,

The raw material composition of the polymer (K) comprises at least one of the tetracarboxylic acid derivatives shown in the formula (I) and at least one of the diamines with a Boc structure,

The raw material composition of the polymer (L) does not contain a tetracarboxylic acid derivative represented by the formula (I) and does not contain diamines having a Boc structure,

In the formula (I), 1', 2 and 2' are bond, each independently bond with hydroxyl, chlorine atom or alkoxy with 1-6 carbon atoms, at least one of the group of 1 and 1 'and the group of 2 and 2' can bond with the same oxygen atom,

R ^b1、R^b2、R^b3 and R ^b4 are each independently a hydrogen atom or a methyl group, at least one of which is a methyl group.

2. The liquid crystal aligning agent according to claim 1, wherein the polymer (K) and the polymer (L) are polyamic acids.

3. The liquid crystal aligning agent according to claim 1, wherein the diamine having a Boc structure comprises at least one of compounds represented by formula (DI-17-2),

In the formula (DI-17-2), e is an integer of 1 to 10, and Boc is a tert-butoxycarbonyl group.

4. The liquid crystal aligning agent according to claim 1, wherein the raw material composition of the polymer (L) comprises at least one of the compounds represented by the formula (DI-5) or the formula (DI-6),

In the formula (DI-5), G ³³ is a single bond 、-NCH₃-、-O-、-S-、-S-S-、-SO₂-、-CO-、-COO-、-CONCH₃-、-CONH-、-C(CH₃)₂-、-C(CF₃)₂-、-(CH₂)_m-、-O-(CH₂)_m-O-、-(O-C₂H₄)_m-O-、-O-CH₂-C(CF₃)₂-CH₂-O-、-O-CO-(CH₂)_m-CO-O-、-CO-O-(CH₂)_m-O-CO- or-S- (CH ₂)_m -S-, or a group represented by the following formula (DI-5-a) or the following formula (DI-5-b), m is independently an integer of 1 to 12,

In the formula (DI-5-a), q is an integer of 0 to 6, R ⁴⁴ is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms,

In the formula (DI-6) and the formula (DI-7), G ²¹ and G ²² are independently a single bond, -O-, -S-, -CO-, -C (CH ₃)₂-、-C(CF₃)₂ -, or an alkylene group having 1 to 10 carbon atoms).

5. The liquid crystal aligning agent according to claim 1, wherein the ratio of the polymer (K) in the liquid crystal aligning agent is 40% by weight or less.

6. The liquid crystal aligning agent according to claim 1, wherein the compound represented by the formula (I) is a compound represented by the formula (I-1),

7. The liquid crystal aligning agent according to claim 1, wherein e is an integer of 2 to 6 in the formula (DI-17-2).

8. The liquid crystal aligning agent according to claim 1, wherein in the formula (DI-17-2), e is 2, 4 or 6.

9. The liquid crystal aligning agent according to claim 4, wherein in the formula (DI-5), G ³³ is-O-or-CH ₂ -, or in the formula (DI-6), G ²¹ and G ²² are-O-.

10. A liquid crystal aligning agent for a photo-alignment type transverse electric field type liquid crystal display element, among the liquid crystal aligning agents described in any one of claims 1 to 9.

11. A liquid crystal alignment film formed from the liquid crystal alignment agent according to any one of claims 1 to 10.

12. A liquid crystal element comprising the liquid crystal alignment film according to claim 11.

13. A method for producing a liquid crystal alignment film, comprising the steps of:

applying the liquid crystal aligning agent of any one of claims 1 to 10 to a substrate;

firing the substrate, and

And irradiating the substrate with polarized ultraviolet rays.