TWI572639B - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Description

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

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film formed from the liquid crystal alignment agent, and a liquid crystal display element.

A film of an organic material made of a polymer material has been attracting attention due to ease of formation, insulating properties, and the like, and is widely used as an interlayer insulating film or a protective film in an electronic device. In terms of materials, acrylic resins, epoxy resins, and polyimide resins are various, but in applications requiring high durability, polyimide resins having high heat resistance are often used. For example, a liquid crystal display element which is well known in the display device uses a film made of polyimine as a liquid crystal alignment film.

The liquid crystal alignment film is a constituent member of a liquid crystal display element widely used in a display device, and can be formed on a surface of a substrate on which a liquid crystal layer is held.

The liquid crystal alignment film functions to align the liquid crystal molecules constituting the liquid crystal layer in a certain direction, and has a function of controlling the pretilt angle of the alignment liquid crystal molecules.

Now, on the liquid crystal alignment film used in the industry, it is widely used. As described above, the polyimine-based organic film having excellent durability and excellent pretilt angle control of the liquid crystal is used. The polyimine-based liquid crystal alignment film is usually formed using a resin composition which can be called a liquid crystal alignment agent or the like.

The resin composition can be prepared into a polymer synthesized from a diamine compound and a tetracarboxylic acid derivative in a respective desired configuration. The polymer to be contained is a polyamic acid which is a polyimide precursor, or a polyimide which is formed by imidating polyphosphonium amide.

In the liquid crystal alignment film, a coating film is formed by using such a resin composition, and the coating film is cured by heating or the like, and can be formed into a cured film made of polyimide.

Polyimine is highly heat-resistant and has excellent durability. However, polyimine itself and polyglycine which is a precursor thereof are often difficult to dissolve in a solvent. Therefore, when a resin composition containing a polymer such as polyimine or polylysine is applied to a substrate or the like, for example, it is required to improve coatability.

Further, when the cured film made of polyimide is used as a liquid crystal alignment film in order to achieve a desired alignment state of liquid crystal molecules, it is necessary to perform an alignment treatment on the cured film.

In the alignment treatment, a rubbing treatment in which a surface of a cured film made of polyimide is rubbed in a certain direction using a cloth is known. However, in addition to the dust generated by the rubbing of the cured film, the rubbing treatment may cause scratches on the surface of the formed liquid crystal alignment film, which may cause various problems such as uneven alignment of liquid crystal molecules. Therefore, in the formation of the liquid crystal alignment film of the liquid crystal display element, the technique of optical alignment processing which does not require rubbing treatment By the attention.

In the liquid crystal display device, the liquid crystal molecules respond by applying a voltage to an electrode provided between the substrate and the liquid crystal alignment film, and the desired image display is performed by the alignment change of the liquid crystal molecules.

The liquid crystal display element has various display modes which are exhibited by the initial alignment state of the liquid crystal molecules or the form of the alignment change by the applied voltage.

In recent years, among liquid crystal display elements, liquid crystal display elements of a vertical alignment (VA) type in which liquid crystal molecules having a negative dielectric anisotropy are aligned perpendicularly to a substrate are widely used for large Screen LCD TV or high-definition mobile portable use (digital camera or mobile phone display). In the VA mode liquid crystal display device, it is required to change the alignment of the liquid crystal molecules in a desired direction parallel to the substrate by applying a voltage. Therefore, in the liquid crystal display element of the VA type, the alignment state of the liquid crystal molecules in the initial stage before the application of the voltage is required, and the liquid crystal molecules must be slightly inclined from the normal direction of the substrate toward one direction in the substrate surface.

In the liquid crystal display device of the VA type, in the initial alignment state before the application of the voltage of the liquid crystal molecules by using the liquid crystal alignment film, it is possible to realize a liquid crystal molecule from the normal direction of the substrate toward the substrate surface with a pretilt angle. The direction is slightly tilted and aligned.

In the VA type liquid crystal display device, a MVA method (Multi Vertical Alignment) in which a protrusion for controlling a direction in which a liquid crystal is tilted is formed on a TFT substrate or a color filter substrate is known, or a substrate is known. The ITO (Indium Tin Oxide) electrode forms a slit, and the PVA (Paterned Vertical Alignment) method of controlling the tilting direction of the liquid crystal is controlled by an electric field. In addition, a liquid crystal alignment film is provided between the substrate and the liquid crystal layer, and the liquid crystal molecules are subjected to a rubbing treatment to align the liquid crystal molecules in a direction from the normal direction of the substrate toward the inside of the substrate surface. 1. The optical alignment method disclosed in Patent Document 2 or the like.

In Patent Document 1 and Patent Document 2, a highly durable polyimine is used, and it is provided in a molecular structure of polyimine, and liquid crystal molecules required for a liquid crystal alignment film for a liquid crystal display device of a VA type are realized. Vertical alignment and optical alignment.

Patent Document 1 uses a diamine compound having a photodimerizing cinnamic acid ester structure and a linear hydrophobic side chain structure in a molecule. Further, a polyamic acid which is a polyimine precursor formed from the diamine compound and the tetracarboxylic dianhydride is synthesized, and the polyamidene is formed from the polyaminic acid to obtain a photoalignment vertical alignment type. Liquid crystal alignment film.

Polyimide-based high-heat-resistant polymer material, suitable for materials with high reliability and use for liquid crystal alignment films. However, polylysine which is a polyimine and a precursor thereof generally has a problem of low solubility in a solvent. In addition, the polyimine used in the liquid crystal alignment agent for liquid crystal display elements of the VA type has a hydrophobic structure due to an alicyclic structure, an alkyl group, a fluorine atom or the like, and is highly hydrophobic when applied to a substrate. There is a problem that ejecting or film thickness unevenness is likely to occur (refer to Patent Document 3).

Therefore, the polylysine and the polyimine formed of the diamine compound described in the above Patent Document 1 are also required to be improved in the solvent. Solubility or improved coating properties on the substrate.

Moreover, the diamine compound described in the above Patent Document 1 has photoreactivity based on the intramolecular cinnamic acid ester structure. Therefore, for example, in the step of forming the liquid crystal alignment film, it is necessary to shield light in the middle, and care must be taken in the operation of the diamine compound. In the case of obtaining a polyimine precursor and a polyimine from a diamine compound having a photoreactive group described in Patent Document 1 and the like, it is necessary to have a countermeasure so that an unnecessary photoreaction does not proceed. Similarly, when the obtained polyimine precursor or polyimine is used to form a liquid crystal alignment film, it is necessary to suppress an unnecessary photoreaction. Therefore, the diamine compound having a photoreactive structure in the molecule such as the cinnamate structure described in Patent Document 1 or the like, and the polyimine precursor and polyimine obtained using the same are used. Light or the like must be taken care of, and the step of forming the liquid crystal alignment film becomes complicated.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 2009-520702

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2011-100099

[Patent Document 3] International Publication No. 2010/079637

In the field of electronic devices, high-durability polyimine is often used as the main component, but in addition to the original features, it can still be used. The specific structure is used for improvement of molecular structure, improvement of characteristics, and the like. For example, as described above, in the liquid crystal display element as an electronic device, the molecular structure of the polyimine is controlled to have a property suitable for use as a liquid crystal alignment film, and is used in a liquid crystal alignment film.

The control of the molecular structure desired in the polyimine, the diamine compound or the like used in the formation of the polyimine, is achieved by controlling the molecular structure thereof. For example, a film of polyimine is used to control the molecular structure of a diamine compound in order to exhibit the performance required for a liquid crystal alignment film, and to synthesize a polymer such as a polyimide precursor and a polyimide by using the diamine compound. . Thereby, a cured film made of a polyimide having a desired molecular structure is formed, and formation of a liquid crystal alignment film having desired characteristics is realized.

In other words, the molecular structure of a diamine compound or the like used in the formation of a polymer such as a polyimine precursor or a polyimide, plays an important role in realizing the desired properties of the polyimide. very important.

However, in the stage of diamine compound used in the formation of polyimine, when a characteristic molecular structure is introduced into a molecule in order to achieve desired characteristics, there is a problem in the step of producing a polyimide.

For example, the formation of a liquid crystal alignment film formed of polyimine is a resin composition containing a polymer such as polylysine formed of a diamine compound (synonymous with a liquid crystal alignment agent, hereinafter also referred to as The liquid crystal alignment agent is prepared, and the resin composition is used for formation of a liquid crystal alignment film. At this time, the diamine compound having a characteristic molecular structure affects the properties of the polymer or the resin composition, and the formation of the liquid crystal alignment film formed by the polyimide. influential.

For example, the diamine compound disclosed in Patent Document 1 has photoreactivity based on a cinnamic acid ester structure in order to realize light alignment of a liquid crystal alignment film. For this reason, in the step of forming the liquid crystal alignment film, it is necessary to shield light in the middle, and it is necessary to pay attention to the operation of the diamine compound. In order to obtain a polymer such as a polyimide precursor or a polyimine from a diamine compound having a photoreactive group, it is necessary to carry out countermeasures such as shading to prevent Do not proceed with the desired light reaction. Further, when the obtained polymer is used to prepare a resin composition, it is also necessary to suppress an undesired photoreaction. Further, when a resin composition is used to form a cured film, it is also necessary to suppress an undesired photoreaction.

It is necessary to pay attention to the diamine compound having a photoreactive structure in the molecule, such as a cinnamate structure disclosed in Patent Document 1 or the like, and a polyimine precursor and a polyimine obtained using the same. Operation, which complicates the formation of the cured film.

Further, the polyimine precursor or the polyimine formed by the diamine compound disclosed in Patent Documents 1 and 2 has insufficient solubility in a solvent, and the molecular structure of the diamine compound is not sufficiently improved. . As a result, when the resin composition is prepared by using these, there is still a problem in the coatability.

In addition, we strongly need a diamine compound which is used in the formation of a liquid crystal alignment film having photo-alignment without the need for shading, etc., and is easy to handle, and can be used for a polymer such as a polyimide precursor and a polyimide. . Furthermore, in the formed polyimide precursor and polyimine, It is required to prepare a resin composition which is excellent in applicability for forming a polyimide film without requiring shading or the like, easy handling, excellent solubility in a solvent, and formation of a polyimide film.

Further, the liquid crystal alignment film formed by using the prepared resin composition is required to have a vertical alignment property and a light alignment property in which the liquid crystal molecules are slightly inclined in a certain direction by photoalignment treatment.

That is, the object of the present invention is to provide a liquid crystal alignment agent which is easy to handle, has excellent coating properties, can form a vertical alignment type photoalignment liquid crystal alignment film, and is used to prepare a polyimine precursor for the liquid crystal alignment agent. A diamine compound produced by polyimine, a photoalignment liquid crystal alignment film having a vertical alignment type, and a liquid crystal display element having the liquid crystal alignment film.

The present invention has the following gist.

(1) A liquid crystal alignment agent characterized by comprising at least one polymer selected from the group consisting of a polyimide precursor having a β-hydroxyester structure and a polyimide having a β-hydroxyester structure.

(2) The liquid crystal alignment agent according to the above (1), wherein the polyimine precursor having a β-hydroxyester structure and the polyimine having a β-hydroxyester structure are composed of a β-hydroxy ester structure The diamine compound is obtained.

(3) The liquid crystal alignment agent according to the above (2), wherein the diamine compound has a structure represented by the following formula (HE-1).

(In the formula (HE-1), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring having 8 to 10 atoms. And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms.

(4) The liquid crystal alignment agent according to the above (2) or (3), wherein the diamine compound has a structure represented by the following formula (HE-2).

(In the formula (HE-2), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring having 8 to 10 atoms. And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms; X ₂ represents a single bond or is represented by an ether, an ester or a decylamine. And at least one divalent bond group selected from the group consisting of urethanes; X ₃ represents a linear alkyl group having 3 to 20 carbon atoms or an alicyclic skeleton having 4 to 40 carbon atoms A monovalent organic group, except that the hydrogen atom of the alkyl group may be substituted with a fluorine atom).

(5) The liquid crystal alignment agent according to any one of the above (2), wherein the diamine compound is a compound represented by the following formula (DA).

(In the formula (DA), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring system having 8 to 10 atoms; And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms; X ₂ represents a single bond or an ether, an ester, a decylamine, and At least one divalent bond group selected from the group consisting of urethanes; X ₃ represents a monovalent chain having a linear alkyl group having 3 to 20 carbon atoms or an alicyclic skeleton having 4 to 40 carbon atoms The organic group, except that the hydrogen atom of the alkyl group may be substituted with a fluorine atom; X ₄ is a single bond, and the methylene group represents a C 2 to 6 alkyl group; however, the alkyl group may be substituted with a hydroxyl group; X ₅ represents a single bond, an oxygen atom, *-OCO- or *-OCH ₂ - (except that the bond bond with "*" is bonded to X ₄ ), but when X ₄ is a single bond, X ₅ is single bond).

(6) A liquid crystal alignment film obtained by the liquid crystal alignment agent according to any one of the above (1) to (5).

(7) A liquid crystal display element having the liquid crystal alignment film of the above (6).

(8) A diamine compound characterized by having a structure represented by the following formula (HE-1).

(In the formula (HE-1), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring having 8 to 10 atoms. And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms.

(9) The diamine compound according to the above (8), which has a structure represented by the following formula (HE-3).

(In the formula (HE-3), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring having 8 to 10 atoms. And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms; X ₂ represents a single bond or is represented by an ether, an ester or a decylamine. And at least one divalent bond group selected from the group consisting of urethanes; X ₆ represents a single bond or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; X ₇ represents A single bond or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; and X ₈ represents a linear alkyl group having 1 to 20 carbon atoms.

(10) The diamine compound according to (8) or (9) above, which is represented by the following formula (DIA).

(In the formula (DIA), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring system having 8 to 10 atoms; And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms; X ₂ represents a single bond or an ether, an ester, a decylamine, and At least one divalent bond group selected from the group consisting of urethanes; X ₆ represents a single bond or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; and X ₇ represents a single bond Or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; X ₈ represents a linear alkyl group having 1 to 20 carbon atoms; and X ₉ represents a single bond, a methylene group or a carbon number of 2 to 6 An alkyl group, except that the alkyl group may be substituted with a hydroxyl group; X ₁₀ represents a single bond, an oxygen atom, *-OCO-, *-OCH ₂ -, *-COO-, *-NHCO- or *-CONH- ( However, the key with "*" is linked to X ₉ ), but when X ₉ is a single key, X ₁₀ is a single key).

(11) A polymer having a β-hydroxyester structure in the molecule obtained by using the diamine compound according to any one of the above (8) to (10).

(12) A liquid crystal alignment agent containing the polymer of (11) above.

(13) A liquid crystal alignment film obtained from the liquid crystal alignment agent of (12) above.

(14) A method for producing a diamine compound, which is a method for producing a diamine compound represented by the following formula (DIA), characterized by comprising the steps of:

a step of obtaining a compound represented by the following formula (C-2) by a reaction of a compound represented by the following formula (C-1) with Meldrum's acid,

a step of obtaining a compound represented by the following formula (C-4) by reacting a compound represented by the formula (C-2) with the following formula (C-3),

The step of reducing the nitro group of the compound represented by the formula (C-4) and reducing the ketone moiety of the β-ketoester structure.

ClOC-X ₁ -X ₂ -X ₆ -X ₇ -X ₈ (C-1)

(In the formulae (DIA), (C-1), (C-2), (C-3), and (C-4), X ₁ represents a monocyclic ring having 5 or 6 atoms, and the number of atoms is 5 or An unsubstituted or substituted carbocyclic ring selected from a group of 6 adjacent monocyclic rings, a ring system of 8 to 10 atoms, and a ring system of 13 or 14 ring atoms. a heterocyclic aromatic group; X ₂ represents a single bond or at least one divalent bond group selected from the group consisting of ethers, esters, guanamines, and urethanes; X ₆ represents a single bond Or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; X ₇ represents a single bond or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; and X ₈ represents a carbon number of 1~ a linear alkyl group of 20; X ₉ represents a single bond, a methylene group or a C 2 to 6 alkyl group, but the alkyl group may be substituted with a hydroxyl group; X ₁₀ represents a single bond, an oxygen atom, *- OCO-, *-OCH ₂ -, *-COO-, *-NHCO- or *-CONH- (only, the key bond with "*" is bonded to X ₉ ), but when X ₉ is a single bond , X ₁₀ is a single button).

According to the present invention, there is provided a diamine compound which is a diamine compound which is easy to handle and which is excellent in solubility and which can form a polymer of a polyimine precursor and a polyimine.

Furthermore, according to the present invention, it is possible to provide a liquid crystal alignment agent which is easy to handle, has excellent coating properties, can form a vertical alignment type photo-alignment liquid crystal alignment film, and can provide a vertical alignment type which can be formed by the liquid crystal alignment agent. Light distribution A liquid crystal alignment film and a liquid crystal display element having the liquid crystal alignment film can be used as a display element capable of displaying high definition images.

Fig. 1 is a graph showing the measurement results of the ultraviolet absorption spectrum before and after firing.

Fig. 2 is a graph showing the measurement results of the ultraviolet absorption spectrum of the cured film of the comparative example.

Fig. 3 is a graph showing the results of measurement of an ultraviolet absorption spectrum after linear polarized light irradiation.

[Formation for implementing the invention]

The present inventors have found the following findings based on the results of the research, and have completed the present invention.

In the liquid crystal display device as the display device, as in the above-described embodiment, a polyimide film having high heat resistance and high strength is often used for the liquid crystal alignment film for alignment of liquid crystal molecules.

In the case of forming a polyimide film for use as a liquid crystal alignment film on a substrate constituting a liquid crystal display element, a method of using a liquid crystal alignment agent as described later is preferred.

In this method, a liquid crystal alignment agent containing a polyimine precursor such as polylysine is prepared. Then, using the obtained liquid crystal alignment agent to form the A method of coating a film to imidize a ruthenium on a substrate to obtain a polyimide film. Further, in another method, a polyimine which is imidized in advance is dissolved in a solvent to prepare a solvent-soluble liquid crystal alignment agent, and a coating film is formed by using the liquid crystal alignment agent to obtain a polymer film. Method of imine film.

The same applies to the method of forming a polyimide film as a liquid crystal alignment film in the liquid crystal display element of the VA mode.

In the liquid crystal display device of the VA type, it is necessary to have a liquid crystal alignment film having a liquid crystal molecule which is slightly inclined from a normal direction of the substrate toward a direction in the substrate surface. In order to obtain such a liquid crystal alignment film, a liquid crystal alignment agent containing a polyimide precursor or a polyimine is used to obtain a polyimide film in which liquid crystal molecules are aligned toward the normal direction of the substrate. Next, the polyimide film is subjected to an alignment treatment, and a liquid crystal molecule is slightly inclined from a normal direction of the substrate toward a direction in the substrate surface to form a desired vertical alignment type liquid crystal alignment film.

Regarding the alignment treatment, it is known that the cloth is rubbed in a certain direction to rub the surface of the polyimide film. However, in addition to rubbing the polyimine film to cause dust generation, the rubbing treatment also causes scratches on the surface of the liquid crystal alignment film, which causes a problem of uneven alignment of liquid crystal molecules, and has various problems.

For this reason, in the manufacture of a liquid crystal display element of the VA type, there is a light alignment technique of a liquid crystal alignment film which does not require rubbing treatment. That is, the development of a vertically aligned photo-alignment liquid crystal alignment film is continuing to progress.

The vertical alignment type photo-alignment liquid crystal alignment film has a structure for realizing vertical alignment of liquid crystal molecules, and realizes optical alignment. Sexual construction. For example, when the liquid crystal alignment agent is formed of a polyimide film, it is used in the formation of a diamine compound or a tetracarboxylic acid derivative for forming a polyimide film, and is used for realizing the perpendicular alignment or photoalignment. The specific constructor is better. At this time, the formed polyimine can realize a liquid crystal alignment film having vertical alignment and photoalignment.

In the above-mentioned Patent Documents 1 and 2, a polyimine film is formed by using a diamine compound having a photodimerization cinnamate structure and a linear hydrophobic side chain structure in a molecule. Next, the polyimide film is subjected to photoalignment treatment to realize a vertically aligned photoalignment liquid crystal alignment film.

However, in the techniques disclosed in Patent Documents 1 and 2, the diamine compound for forming a polyimine has a photoreactive structure due to a cinnamic acid ester structure in the molecule. For this reason, it is necessary to pay attention to shading or the like in this operation. That is, in the formation step of the polyimide precursor or the formation step of the polyimide, it is necessary to take care to suppress unnecessary photoreaction or countermeasures.

Further, as described above, in the structures of the polyimine precursor or the polyimine disclosed in Patent Documents 1 and 2, the molecular structure is improved in solubility in a solvent or coating property on a substrate. The improvement is not sufficient. Therefore, the use of these to prepare a liquid crystal alignment agent still has a problem in coating properties of the obtained liquid crystal alignment agent.

The diamine compound of the present invention is a novel compound having a characteristic molecular structure, and is suitable for synthesis of a polymer of a polyimine precursor and a polyimine.

Although the diamine compound of the present invention does not have photoreactivity itself, the cured film obtained from the polymer formed of the compound may have photoreactivity. That is, it is suitable for providing a liquid crystal alignment film made of a polyimide having a structure suitable for photoalignment treatment. It is particularly suitable for providing a vertical alignment type photoalignment liquid crystal alignment film in which a VA type liquid crystal display element is formed.

The diamine compound of the present invention has a β-hydroxyester structure in the molecule. Further, the liquid crystal alignment film formed using the diamine compound has a structure suitable for realizing vertical alignment of liquid crystal molecules.

The β-hydroxyester structure in the molecule undergoes a dehydration reaction by heating to form a photoreactive double bond.

The diamine compound having a β-hydroxyester structure of the present invention reacts with a tetracarboxylic acid derivative to provide a polymer such as a polyimine precursor and a polyimine. The coating film formed using the liquid crystal alignment agent containing the obtained polymer generates a photoreactive double bond in the molecular structure due to heating after being formed.

For example, a polyimine precursor is synthesized from a diamine compound having a β-hydroxyester structure, and a liquid crystal alignment agent containing the obtained polyimide intermediate precursor can be prepared. In this case, the coating film of the liquid crystal alignment agent is heated to carry out the oxime imidization reaction of the polyimine precursor component, and the dehydration reaction occurs in the β-hydroxyester structure, thereby introducing photoreactivity into the molecule. Double key.

Further, by partially heating the coating film of the liquid crystal alignment agent, a portion of the cured film having photoreactivity is prepared and has no photoreaction A portion of the polyamidene precursor is mixed with the cured film.

That is, it is possible to distinguish between a portion having a photoreactive group and a portion having no photoreactivity on the same film. Thereby, a conventional negative pattern forming step of coating the surface of the resin with a mask or the like and irradiating the light can be carried out, and the heating step can be made only by the heating step without the mask.

Further, by synthesizing polyimine from a diamine compound having a β-hydroxyester structure, a liquid crystal alignment agent containing the obtained polyimine can be prepared. At this time, the coating film of the liquid crystal alignment agent is heated to form a polyimide film, and a dehydration reaction occurs in the β-hydroxyester structure portion, whereby a photoreactive double bond is introduced into the molecule.

By introducing a double bond intramolecularly as described above, the polymer of the polyimine precursor and the polyimine in the present invention can form a cured film composed of polyimine and simultaneously in the molecule. A photoreactive site such as a cinnamate structure or the like is introduced. As a result, the cured film formed of the polymer can exhibit photoreactivity. That is, the liquid alignment film formed by using such a cured film can achieve optical alignment.

Further, in the present invention, when the diamine compound forms a liquid crystal alignment film, it also has a molecular structure suitable for aligning liquid crystal molecules in the normal direction of the substrate. The cured film formed by the polyimine precursor synthesized by the diamine compound having a β-hydroxyester structure and at least one polymer of the polyimine can be used as a vertical alignment type photoreaction. Liquid crystal alignment film.

The diamine compound having a β-hydroxyester structure of the present invention does not have a photoreactive structure in the molecule and is stable to light. Therefore, this operation does not require attention or countermeasures.

The diamine compound having a β-hydroxyester structure of the present invention is a polymer obtained by synthesizing a polyimide intermediate having a β-hydroxyester structure and a polyimine. The obtained polymer does not have a photoreactive structure in the molecule and does not have photoreactivity before introduction of a double bond. Therefore, the polymer of the present invention is stable to light, and the operation is as conventional, without attention or countermeasures. The photoreactive double bond can be introduced into the structure after it is formed of a cured film made of a polymer.

Further, the polyimine precursor of the present invention and a polymer such as polyimine have a β-hydroxyester structure in the molecule, and have a high solubility in a solvent by having a hydroxyl group derived from the structure in the molecule. Sex. Therefore, the liquid crystal alignment agent of the present invention contains a polyimine precursor and a polymer such as polyimine with high solubility and excellent coatability.

For this reason, in order to improve the coating property, the amount of the poor solvent contained in the butyl sirolius or the like may be varied. Further, since the polymer itself has a hydroxyl group at the side chain portion, it has high hydrophilicity and excellent coatability to the substrate.

The diamine compound of the present invention has a β-hydroxyester structure and a linear hydrophobic side chain structure in the molecule.

The diamine compound of the present invention reacts with a tetracarboxylic acid derivative to provide a polymer such as a polyimine precursor or a polyimine.

The polymer of the present invention can be dissolved in a solvent or the like to form a liquid crystal alignment agent, and after forming a coating film, a cured film can be formed.

The cured film of the present invention has a β-hydroxyester structure derived from a diamine compound and has a photoreactive double bond in the molecule, and has a linear hydrophobic side chain structure. Therefore, the cured film of the present invention can form a liquid The crystal alignment film is suitable for photoalignment treatment in a liquid crystal alignment film, and provides a photoalignment liquid crystal alignment film which can form a vertical alignment type.

The present inventors have developed a polyimide-polyimine and a polyimide precursor having a novel structure for use in a vertical alignment type photoalignment liquid crystal alignment film.

The polyimine and the polyimine precursor of the present invention each have a β-hydroxyester structure in a molecule, and have a structure for realizing vertical alignment of liquid crystal molecules.

There are various methods for forming polyimine and polyimine precursors for use in a vertical alignment type photoalignment liquid crystal alignment film having the novel structure of the present invention. It has also been found that a method of using a novelly constructed diamine compound is particularly preferred.

The diamine compound of the present invention has a β-hydroxyester structure in a molecule and has a structure for realizing vertical alignment of liquid crystal molecules.

The polyimine precursor of the present invention and the polyimine obtained by imidating the precursor with ruthenium have a β-hydroxyester structure in the molecule.

The method for obtaining a polyimine precursor having a β-hydroxyester structure in a molecule can be achieved by a method using a diamine compound having a β-hydroxyester structure in a molecule. Further, it is achieved by a method of using a tetracarboxylic acid derivative having a β-hydroxyester structure in a molecule.

Further, when a diamine compound and a tetracarboxylic acid derivative are polymerized to obtain a polyimine precursor, and a compound having a β-hydroxyester structure in the molecule is used as an additive, the formed polyfluorene is formed. Imine precursor A method of introducing a β-hydroxyester structure.

In the method for introducing a β-hydroxyester structure as described above, a method of using the diamine compound of the present invention having a β-hydroxyester structure in a molecule is particularly preferable from the viewpoint of reliability.

Hereinafter, the present invention which is used for a diamine compound having a β-hydroxyester structure in a molecule will be described in detail.

Further, in the present invention, in the case of a polyimine precursor, polyphthalic acid, polyphthalamide or the like is contained.

<Diamine compound having a β-hydroxyester structure>

The diamine compound of the present invention is a diamine compound having a β-hydroxyester structure. The β-hydroxyester structure can be represented by the following formula (HE).

The diamine compound of the present invention is preferably a structure having the following formula (HE-1). By using a structure having the following formula (HE-1), the polyimine precursor formed by using the diamine compound and the polyimine precursor are subjected to ruthenium imidization of the polyimide, when heated A double bond having excellent photoreactivity can be formed in the molecule. When a polyimine precursor formed with a double bond and a polyimide precursor are subjected to a ruthenium imidization, when used for formation of a liquid crystal alignment film, excellent optical alignment performance can be exhibited.

In the above formula (HE-1), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring having 8 to 10 atoms. An unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms.

Among the structures of the above formula (HE-1), a particularly preferable structure is a structure represented by the following formula (HE-1-1). The polyimine precursor and the polyimine formed by using a diamine compound having a structure represented by the following formula (HE-1-1) can be formed into a photoreactive molecule in the molecule upon heating. Double key. The polyimine which is obtained by imidating a polyimine imide precursor and a polyimine precursor formed with a double bond can exhibit excellent optical alignment properties when used for formation of a liquid crystal alignment film. .

The diamine compound of the present invention is preferably a structure having a β-hydroxyester structure and a structure of the following formula (HE-2) having a structure for realizing vertical alignment of liquid crystal molecules.

In the above formula (HE-2), X ₁ is synonymous with the above formula (HE-1).

In the above formula (HE-2), X ₂ represents a single bond or at least one divalent bond group selected from the group consisting of an ether, an ester, a guanamine, and a urethane.

In the X ₂ aspect, a single bond, an ether group, an ester group or a decylamino group is preferred, and a single bond, an ether group or an ester group is more preferred.

X ₃ represents a monovalent organic group having a linear alkyl group having 3 to 20 carbon atoms or an alicyclic skeleton having 4 to 40 carbon atoms, and the hydrogen atom of the alkyl group may be substituted with a fluorine atom.

The X ₃ aspect may, for example, be n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-fluorenyl, n-fluorenyl, n- eleven Alkyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, cyclobutyl, cyclopentyl, cyclohexyl, ring Heptyl, cyclooctyl, adamantyl, spiro[5.5]undecyl, bicyclo[2.2.2]octyl, bicyclo[2.2.1]heptyl, cyclohexyl-n-heptyl, bicyclo Hexyl-n-pentyl, phenyl, naphthyl, anthracenyl, cyclohexylphenyl, n-pentyl-cyclohexylphenyl, n-heptyl-cyclohexylphenyl, cyclohexyloxyphenyl or n- Pentyl-cyclohexyloxyphenyl is preferred, n-octyl, n-fluorenyl, n-fluorenyl, n-undecyl, n-dodecyl, cyclohexyl, cyclohexyl-n-g More preferably, a dicyclohexyl-n-pentyl group, a cyclohexyloxyphenyl group or an n-pentyl-cyclohexyloxyphenyl group.

The linear alkyl group having 3 to 20 carbon atoms as X ₃ has a function as a hydrophobic side chain structure in the present invention.

Preferred examples of the diamine compound of the present invention include compounds represented by the following formula (DA).

In the above formula (DA), the X ₁ system is synonymous with the definition in the above formula (HE-1), and the preferred examples are also the same.

The X ₂ system is synonymous with the definition in the above formula (HE-2), and the preferred examples are also the same.

The X ₃ system is synonymous with the definition in the above formula (HE-2), and the preferred examples are also the same.

X ₄ is a single bond, and a methylene group also represents an alkylene group having 2 to 6 carbon atoms. However, the alkylene group may be substituted with a hydroxyl group.

In the X ₄ aspect, it is preferably a single bond, a methylene group, an ethylidene group, an n-propyl group, an n-butylene group, a single bond or an ethyl group.

X ₅ represents a single bond, an oxygen atom, *-OCO- or *-OCH ₂ - (except that the bond bond with "*" is bonded to X ₄ ), but when X ₄ is a single bond, X ₅ is single bond.

In the case of X ₅ , a single bond, an oxygen atom or *-OCH ₂ - is preferable, and *-OCH ₂ - or an oxygen atom is more preferable.

Preferred examples of the diamine compound represented by the above formula (DA) The surface of the surface may be a diamine compound represented by the following formulas (DA-1) to (DA-8).

In the above formula (DA-1) to (DA-8), R _a is a C 3 - 20 alkyl group in which _a hydrogen atom may be substituted by a fluorine atom.

The X _a side may, for example, be a linear alkyl group having 3 to 16 carbon atoms, for example, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, N-fluorenyl, n-fluorenyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl or n-hexadecane The group is preferably a n-octyl group, an n-fluorenyl group, an n-fluorenyl group, an n-undecyl group or an n-dodecyl group.

R _b is an alkyl group having 1 to 20 carbon atoms or a hydrogen atom having 1 to 20 carbon atoms which may be substituted by a fluorine atom.

In the case of X _b , a linear alkyl group having 1 to 12 carbon atoms is, for example, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group or an n-heptyl group. , n-octyl, n-fluorenyl, n-fluorenyl, n-undecyl or n-dodecyl is preferred, n-propyl, n-butyl, n-pentyl, n-hexyl Or n-heptyl is preferred.

Further, the diamine compound of the present invention is preferably a diamine compound having a β-hydroxyester structure, and a structure having the structure of the following formula (HE-3) for realizing a vertical alignment of liquid crystal molecules.

In the formula (HE-3), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring system having 8 to 10 atoms. And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms.

Examples of X ₁ include a benzene ring, a naphthalene ring, a cyclopentadiene, an anthracene ring, an anthracene ring, an anthracene ring, a furan ring, a thiophene ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a benzofuran ring, and an anthracene. An anthracene ring, a quinoline ring, a benzimidazole ring, a quinoxaline ring, an indazole ring, an anthracene ring or a xanthene ring is preferred, and a benzene ring or a naphthalene ring is preferred.

X ₂ represents a single bond or at least one divalent bond group selected from the group consisting of ethers, esters, guanamines, and urethanes.

In the X ₂ aspect, a single bond, an ether group, an ester group or a decylamino group is preferred, and a single bond, an ether group or an ester group is more preferred.

X ₆ represents a single bond or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms.

In the X ₆ aspect, it is cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl, spiro[5.5]undecyl, bicyclo[2.2.2]octyl, bicyclo [2.2.1] A heptyl group, a phenyl group, a naphthyl group or an anthracenyl group is preferred, a cyclohexyl group or a phenyl group is more preferred.

X ₇ represents a single bond or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms.

In the aspect of X ₇ , it is cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl, spiro[5.5]undecyl, bicyclo[2.2.2]octyl, bicyclo [2.2.1] Heptyl, phenyl, naphthyl, anthracenyl is preferred, cyclohexyl or phenyl is more preferred.

X ₈ represents a linear alkyl group having 1 to 20 carbon atoms.

In the case of X ₈ , a linear alkyl group having 1 to 12 carbon atoms, for example, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, N-octyl, n-fluorenyl, n-fluorenyl, n-undecyl or n-dodecyl is preferred, n-propyl, n-butyl, n-pentyl, n-hexyl or The n-heptyl group is more preferred.

Among the linear alkyl groups having 1 to 20 carbon atoms of X ₈ , a linear alkyl group having 1 to 20 carbon atoms has a function as a hydrophobic side chain structure in the present invention.

In the aspect of the diamine compound of the present invention having the above configuration, A diamine compound represented by the following formula (DIA) is preferred.

In the formula (DIA), the X ₁ system is synonymous with the definition in the above formula (HE-3), and the preferred examples are also the same.

The X ₂ system is synonymous with the definition in the above formula (HE-3), and the preferred examples are also the same.

The X ₆ system is synonymous with the definition in the above formula (HE-3), and the preferred examples are also the same.

The X ₇ system is synonymous with the definition in the above formula (HE-3), and the preferred examples are also the same.

The X ₈ system is synonymous with the definition in the above formula (HE-3), and the preferred examples are also the same.

X ₉ represents a single bond, a methylene group or an alkylene group having 2 to 6 carbon atoms, but the alkylene group may be substituted with a hydroxyl group.

In the case of X ₉ , a single bond, a methylene group, an ethylidene group, an n-propyl group or an n-butylene group is preferred, and a single bond or an ethyl group is preferred.

X ₁₀ represents a single bond, an oxygen atom, *-OCO-, *-OCH ₂ -, *-COO-, *-NHCO- or *-CONH- (except for the "*" bond bond and the X ₉ bond Knot), except that when X ₉ is a single bond, X ₁₀ is a single bond.

In the case of X ₁₀ , a single bond, an oxygen atom, *-OCO-, *-OCH ₂ - or *-COO- is preferred, and -OCH ₂ - or an oxygen atom is more preferred.

Examples of the diamine compound represented by the formula (DIA) include diamine compounds represented by the following formulas (DIA-1) to (DIA-7).

Further, in the present invention, in addition to the diamine compound having a β-hydroxyester structure, a diamine compound having a β-hydroxyketone structure as shown by the following formula (HK-1) can be exemplified as a preferred diamine compound. . The diamine compound having a β-hydroxyketone structure can be used in the synthesis of a polymer of a polyimine precursor of the present invention and a polyimine.

Although the diamine compound itself does not have photoreactivity, the cured film formed from the polymer synthesized using the diamine compound can introduce a photoreactive double bond structure into the molecule by heating or the like, and has light. Reactivity. Therefore, it is suitable for providing a liquid crystal alignment film made of polyimide by a structure suitable for photoalignment treatment. In particular, it is suitable for providing a vertical alignment type photoalignment liquid crystal alignment film suitable for formation of a liquid crystal display element of a VA type.

Examples of the diamine compound represented by the formula (HK-1) include a diamine compound represented by the following formula (DIA-8) to (DIA-11).

The method for forming the β-hydroxyester structure in the diamine compound of the present invention is not particularly limited. For example, a zinc alkoxide can be prepared from a corresponding α-haloester by a Reformatsky reaction to form a reaction with an aldehyde.

Further, a method in which an α-haloester and an aldehyde are reacted in the presence of a metal alkoxide to form a Darzens condensation of a synthetic epoxide, and then derivatized into a β-hydroxyester by hydrolysis is carried out.

Further, in another method, a β-ketoester which is a precursor of a β-hydroxyester is used, and sodium borohydride or sodium cyanoborohydride is used, and only a ketone moiety is selectively reduced in the presence of an ester. It is also possible to synthesize a β-hydroxy ester. Further, a method in which a ketone moiety is reduced under a metal catalyst such as Ru to obtain a desired β-hydroxyester.

As a method for synthesizing a β-ketoester as a precursor of a β-hydroxyester, when α-hydrogen is not acidic in one of the esters, the target β-ketoester or β- is synthesized by cross-Claisen condensation. a method of reacting a ketoenolate with a alkyl cyanide (Mander Reagent), an acid imidazolidinone from a carbonyldiimidazole and a carboxylic acid, and reacting it with a monoalkylmagnesium malonate Method, etc.

In the present invention, a preferred method for synthesizing a diamine compound having a β-hydroxyester structure is as follows.

First, Meldrum's acid is synthesized by reacting Meldrum's acid in the presence of a base catalyst with a carboxylic acid chloride having a skeleton as a target. Next, the target β-ketoester body is synthesized by reacting the Meldrum's acid derivative with an alcohol having a structure equivalent to a nitro group which is subsequently reduced to an amine group. Thereafter, the nitro group in the molecule is reduced by hydrogenation, and the ketone is reduced by sodium borohydride to form a β-hydroxyester structure, whereby a diamine compound having a novel structure can be synthesized.

In particular, when the diamine compound as described above is synthesized, it is an aromatic ring having an electron-attracting group such as a nitro group which can be reduced to an amine group in the molecule, and further has a benzyl structure. At this point, benzyl The acidity of the bit becomes high, a common side reaction occurs in the presence of a strong base, and the desired synthesis reaction cannot proceed well. In the synthesis of a β-hydroxyester or a β-ketoester, in general, the Claisen condensation or the like is carried out in the presence of a strong base catalyst to cause the reaction to proceed, and the protons of the α hydrogen are extracted as described above. In the case where there are protons in the benzyl group, undesired side reactions occur, and the reaction does not proceed.

In the synthesis method of the diamine compound having a β-hydroxyester structure of the present invention, it is desirable to select a production method for avoiding the use of a strong base. For example, even when dinitrobenzyl alcohol is used as a raw material, the synthesis of the desired compound can be efficiently achieved by suppressing the side reaction.

The main steps of the method for producing the diamine compound represented by the above formula (DIA) are as follows.

And a step of obtaining a compound represented by the following formula (C-2) by a reaction of a compound represented by the following formula (C-1) with Meldrum's acid, by the formula (C-2) The compound shown below is reacted with the following formula (C-3) to obtain a compound of the following formula (C-4), a nitro group of the compound of the formula (C-4), and further reduced β. - The step of the ketone moiety of the ketoester structure.

ClOC-X ₁ -X ₂ -X ₆ -X ₇ -X ₈ (C-1)

X ₁ , X ₂ , X ₆ , X ₇ , X ₈ in the formula (DIA), the formula (C-1), the formula (C-2), the formula (C-3), and the formula (C-4), The X ₉ and X ₁₀ systems are synonymous with the definitions of the above formulas (HE-3) and (DIA), and the preferred examples are also the same.

However, when X ₉ is a single bond, X ₁₀ is a single bond.

<Other diamine compounds>

The above formula (DA) or formula can be used alone in combination with the tetracarboxylic acid derivative to synthesize the polyimine precursor of the present invention and the diamine used for the polyimide. Diamine compound shown by DIA). Further, a compound represented by the above formula (DA) or (DIA) or another diamine compound represented by the following formula (AM) may be used in combination.

In the above formula (AM), Y ₁ is a divalent organic group, and two or more kinds may be mixed. Further, in the above formula (AM), R ¹ and R ^{2 each} represent a hydrogen atom or a monovalent organic group.

More specifically, in the above formula (AM), R ¹ to R ² each independently represent a hydrogen atom or an alkyl group, an alkenyl group or an alkynyl group having 1 to 10 carbon atoms which may have a substituent.

Specific examples of the alkyl group having 1 to 10 carbon atoms which may have a substituent include a methyl group, an ethyl group, a propyl group, a butyl group, a t-butyl group, a hexyl group, an octyl group, a decyl group, and a cyclopentyl group. Cyclohexyl, dicyclohexyl and the like.

The alkenyl group having 1 to 10 carbon atoms which may have a substituent may be a structure in which one or more CH ₂ -CH ₂ groups present in the above alkyl group are substituted with a CH=CH structure. More specifically, vinyl, allyl, 1-propenyl, isopropenyl, 2-butenyl, 1,3-butadienyl, 2-pentenyl, 2-hexenyl, cyclopropene Base, cyclopentenyl, cyclohexenyl and the like.

The alkynyl group having 1 to 10 carbon atoms which may have a substituent may be a structure in which one or more CH ₂ -CH ₂ structures present in the above-mentioned alkyl group are substituted into a C≡C structure. More specifically, ethynyl, 1-propynyl, 2-propynyl and the like.

The above-mentioned alkyl group, alkenyl group or alkynyl group may have a substituent in the total number of carbon atoms of from 1 to 10, and may further form a ring structure by a substituent. Further, the formation of a ring structure by a substituent means that a substituent or a substituent is bonded to a part of a parent skeleton to form a ring structure.

Examples of the substituent include a halogen group, a hydroxyl group, a thiol group, a nitro group, an aryl group, an organic oxy group, an organic thio group, an organic decyl group, a decyl group, an ester group, a thioester group, a phosphate group, and Amidino, alkyl, alkenyl, alkynyl.

Examples of the halogen group as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

A phenyl group is mentioned as an aryl group of a substituent. Other substituents in the aryl group as described above may be further substituted.

As the organooxy group as a substituent, a structure represented by O-R can be exhibited. R may be the same or different, and examples thereof include an alkyl group, an alkenyl group, an alkynyl group, an aryl group and the like as described above. In the above R, the aforementioned substituent may be further substituted. Specific examples of the organic oxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, and an octyloxy group.

As the organothio group as a substituent, a structure represented by -S-R can be represented. In the aspect of R, an alkyl group, an alkenyl group, an alkynyl group, an aryl group or the like as described above can be exemplified. In the above R, the aforementioned substituent may be further substituted. Specific examples of the organic sulfur group include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, and an octyl group. Sulfur-based, etc.

The aspect of the organoalkylene group as a substituent may represent a structure represented by -Si-(R) ₃ . R may be the same or different, and examples thereof include an alkyl group, an alkenyl group, an alkynyl group, an aryl group and the like as described above. In the above R, the aforementioned substituent may be further substituted. Specific examples of the organic decyl group include a trimethyl decyl group, a triethyl decyl group, a tripropyl decyl group, a tributyl decyl group, a tripentyl decyl group, a trihexyl decyl group, and a pentyl dimethyl group. Base alkyl, hexyl dimethyl decyl, and the like.

As the thiol group of the substituent, a structure represented by -C(O)-R can be represented. In the aspect of R, an alkyl group, an alkenyl group, an aryl group or the like as described above can be exemplified. In the above R, the aforementioned substituent may be further substituted. Specific examples of the mercapto group include a methyl group, an ethyl group, a propyl group, a butyl group, an isobutyl group, a pentamidine group, an isovaleryl group, a benzamidine group, and the like.

As the ester group of the substituent, a structure represented by -C(O)O-R or OC(O)-R can be represented. In the aspect of R, an alkyl group, an alkenyl group, an alkynyl group, an aryl group or the like as described above can be exemplified. In the above R, the aforementioned substituent may be further substituted.

As the thioester group as a substituent, a structure represented by -C(S)O-R or OC(S)-R can be represented. In the aspect of R, an alkyl group, an alkenyl group, an alkynyl group, an aryl group or the like as described above can be exemplified. In the above R, the aforementioned substituent may be further substituted.

As the phosphate group of the substituent, a structure represented by -OP(O)-(OR) ₂ can be represented. R may be the same or different, and examples thereof include an alkyl group, an alkenyl group, an alkynyl group, an aryl group and the like as described above. In the above R, the aforementioned substituent may be further substituted.

As the amide group of the substituent, it may represent -C(O)NH ₂ or -C(O)NHR, -NHC(O)R, -C(O)N(R) ₂ , -NRC(O)R The configuration shown. R may be the same or different, and examples thereof include an alkyl group, an alkenyl group, an alkynyl group, an aryl group and the like as described above. In the above R, the aforementioned substituent may be further substituted.

The aryl group as a substituent may be the same as the above aryl group. In the aryl group, the other substituents described above may be further substituted.

The alkyl group as a substituent may be the same as the alkyl group described above. In the alkyl group, the other substituents described above may be further substituted.

The alkenyl group as a substituent may be the same as the above alkenyl group. In the alkenyl group, the other substituents described above may be further substituted.

The alkynyl group as a substituent is the same as the alkynyl group mentioned above. In the alkynyl group, the other substituents described above may be further substituted.

In general, when a structure having a high bulk density is introduced, the reactivity of the amine group or the liquid crystal alignment property may be lowered, so that R ¹ and R ² are a hydrogen atom or a carbon number which may have a substituent of 1 to 5. The alkyl group is preferably a hydrogen atom, a methyl group or an ethyl group.

In the above formula (AM), when the specific display configuration example of Y ₁ include Y-1 ~ Y-106 as shown as follows, but not limited to these.

<tetracarboxylic acid derivative>

The polyimine precursor or the polycarboxylic acid derivative of the polyimine which can be contained in the liquid crystal alignment agent of the present invention can be used for the reaction of the above diamine compound, and is not particularly limited.

Examples of the tetracarboxylic acid derivative include tetracarboxylic dianhydride (shown by the following formula (CB1)), tetracarboxylic acid monoanhydride (shown by the following formula (CB2)), and tetracarboxylic acid (the following formula ( CB3)), a dialkyl dicarboxylate (shown by the following formula (CB4)), a dialkyl dicarboxylate (shown by the following formula (CB5)), and the like. Tetracarboxylic acid derivative In terms of one type, one type may be used alone or two or more types may be used in combination.

In the above formulae (CB4) and (CB5), R ³ represents an alkyl group having 1 to 5 carbon atoms, preferably 1 to 2 carbon atoms.

In the above formula (CB1) to (CB5), specific examples of Z ₁ include the following formula (Z-1) to formula (Z-46).

<Polyimide precursor>

The polyimine precursor contained in the liquid crystal alignment agent of the present invention contains the above formula (DA), the above formula (DIA), etc. having a β-hydroxyester structure. The diamine compound is a combination of the diamine components of the essential components.

The polyimine precursors are, for example, polylysine and polyphthalate, and have a structural unit represented by the following formula (PA).

In the above formula (PA), Z is derived from tetracarboxylic dianhydride, tetracarboxylic acid monoanhydride, tetracarboxylic acid, dialkyl dicarboxylate and dicarboxylic acid chloride as examples of the above tetracarboxylic acid derivative. The group of the Z ₁ group among the alkyl esters.

Further, R _C represents a hydrogen atom or a monovalent organic group derived from the above tetracarboxylic acid derivative or an esterifying agent described later, and preferably an alkyl group having 1 to 5 carbon atoms, more preferably 1 to 2 carbon atoms.

In the formula (PA), Y corresponds to the group of the above-described diamine compound having a β-hydroxyester structure and the group derived from the Y ₁ group of the other diamine compound represented by the above formula (AM). A ₁ and A ₂ represent a hydrogen atom or a monovalent organic group derived from the R ¹ group and the R ² group of the other diamine compound represented by the above formula (AM).

The polyaminic acid which is a polyimine precursor of the present invention, for example, may contain a diamine compound having a β-hydroxyester structure by a diamine compound of the above formula (DA) or the above formula (DIA). A diamine component (hereinafter simply referred to as a diamine component) as an essential component and a tetracarboxylic acid as a tetracarboxylic acid derivative It is obtained by the reaction of acid dianhydride.

A known method can be employed in the method of reacting the diamine component of the polyphthalic acid contained in the liquid crystal alignment agent of the present invention with the tetracarboxylic dianhydride. This reaction method is a method of reacting a diamine component with a tetracarboxylic dianhydride in an organic solvent. The reaction between the diamine component and the tetracarboxylic dianhydride is advantageous because it is relatively easy to carry out in the organic solvent and does not cause by-products.

In the case of an organic solvent, those which dissolve the produced polyamic acid are not particularly limited. Specific examples thereof are as follows.

N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylene Ester, dimethyl hydrazine, tetramethyl urea, pyridine, dimethyl hydrazine, hexamethyl hydrazine, γ-butyrolactone, isopropanol, methoxymethylpentanol, dipentene, ethyl Pentanone, methyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl stilbene, ethyl serotonin, methyl sarbuta acetate, ethyl赛路苏acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, Propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, Dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate single Propyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl Ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, pentyl acetate, butyl butyrate, butyl ether, diisobutyl Ketone, methylcyclohexane Alkene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate , ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, 3-methoxypropionic acid Base ester, 3-ethyloxypropionic acid methyl ethyl ester, 3-methoxypropionic acid ethyl ester, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid Propyl ester, butyl 3-methoxypropionate, diethylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N,N-dimethyl Propane decylamine, 3-ethoxy-N,N-dimethylpropane decylamine, 3-butoxy-N,N-dimethylpropane decylamine, and the like.

The above organic solvent may be used singly or as a mixture. Further, even a solvent which does not dissolve polylysine may be used by mixing the organic solvent in a range in which the produced polyamine does not precipitate.

Further, since the water in the organic solvent hinders the polymerization reaction and further causes hydrolysis of the produced polylysine, it is preferred that the organic solvent is dried as much as possible.

When the diamine component and the tetracarboxylic dianhydride are reacted in an organic solvent, the diamine component may be dispersed or dissolved in an organic solvent to form a solution, and the tetracarboxylic dianhydride may be directly added or stirred while stirring. A method of dispersing or dissolving in an organic solvent to add, in contrast, a method in which a tetracarboxylic dianhydride is dispersed or dissolved in an organic solvent to form a solution, and a diamine component is added thereto, and tetracarboxylic dianhydride is added to each other. Any of these methods can be used as the method of the diamine component. Further, the diamine component or the tetracarboxylic dianhydride is multiplied When the compound is formed, even if it is reacted in a state of being premixed, it may be reacted individually in order, and even a low molecular weight body which is individually reacted may be mixed and reacted to form a high molecular weight body.

The reaction (polymerization) temperature may be any temperature of from -20 to 150 ° C, but preferably from -5 to 100 ° C. Further, although the reaction can be carried out at any concentration, if the concentration is too low, it is difficult to obtain a polymer having a high molecular weight, and if the concentration is too high, the viscosity of the reaction liquid becomes too high, and it is difficult to uniformly stir. Therefore, the total concentration in the reaction solution of the diamine component and the tetracarboxylic dianhydride is preferably from 1 to 50% by mass, more preferably from 5 to 30% by mass. The initial stage of the reaction is carried out at a high concentration, and then an organic solvent can be added.

In the reaction (polymerization), the ratio of the total number of moles of the tetracarboxylic dianhydride to the total number of moles of the diamine component is preferably from 0.8 to 1.2. As with the general polycondensation reaction, the closer the molar ratio is to 1.0, the greater the molecular weight of the resulting polyamic acid.

<Polyurethane>

The polyimine precursor which may be contained in the liquid crystal alignment agent of the present invention has poly-proline and polyphthalamide as described above. As the polyphthalate ester of the polyimide precursor, for example, a diamine compound having a β-hydroxyester structure containing a diamine compound of the above formula (DA) or the above formula (DIA) can be used as an essential component. The diamine component and the tetracarboxylic acid derivative are synthesized by the methods (1) to (3) shown below.

(1) Method for synthesizing polyglycine

It can be synthesized by esterifying a polyamic acid obtained from a diamine component and a tetracarboxylic dianhydride.

Specifically, the polyglycolic acid and the esterifying agent are allowed to react in the presence of an organic solvent at -20 to 150 ° C, preferably 0 to 50 ° C for 30 minutes to 24 hours, preferably 1 to 4 hours to synthesize.

In terms of the esterifying agent, it is preferably removed by purification, and examples thereof include N,N-dimethylformamide dimethyl acetal and N,N-dimethylformamide diethyl ester. Acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamide dineopentyl butyl acetal, N,N-dimethylformamide - butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene 4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholine quinone chloride.

The amount of the esterifying agent to be added is preferably from 2 to 10 mol equivalents and more preferably from 2 to 6 mol equivalents per 1 mol of the repeating unit of polyglycine.

The organic solvent used in the reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone or γ-butyrolactone from the viewpoint of solubility of the polymer. These may be used alone or in combination of two or more.

The concentration of the polyaminic acid in the reaction is preferably from 1 to 30% by mass, more preferably from 5 to 20% by mass, from the viewpoint that precipitation of the polymer is less likely to occur and a high molecular weight body is easily obtained.

(2) by the inverse of the tetracarboxylic acid diester dichloride and diamine components Method of synthesis

It can be synthesized by the reaction of a tetracarboxylic acid diester dichloride with the above diamine component.

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

As the base, pyridine, triethylamine, 4-dimethylaminopyridine or the like can be used, and in order to carry out the reaction gently, pyridine is preferred.

The amount of the base to be added is preferably from 2 to 10 moles to 2 to 4 moles for the tetracarboxylic acid diester dichloride from the viewpoint of easy removal amount and easy availability of a high molecular weight body. Better.

In terms of solubility of the monomer and the polymer, N-methyl-2-pyrrolidone and γ-butyrolactone are preferred, and one type or a mixture of two types may be used. Used above.

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

Further, in order to avoid hydrolysis of the tetracarboxylic acid diester dichloride, it is preferred that the solvent used in the synthesis of the polyphthalate is desalted as much as possible, and it is preferable to prevent the outside air from being mixed in a nitrogen atmosphere.

(3) A method for synthesizing by reacting a tetracarboxylic acid diester with a diamine component

It can be synthesized by polycondensing a tetracarboxylic acid diester with the above diamine component.

Specifically, the tetracarboxylic acid diester and the above diamine component can be reacted in the presence of a condensing agent, a base, and an organic solvent at 0 ° C to 150 ° C, preferably 0 to 100 ° C. It is synthesized in minutes to 24 hours, preferably 3 to 15 hours.

As the condensing agent, triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N can be used. , N'-carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholine oxime, O-(benzotriazol-1-yl)-N,N,N',N '-Tetramethylurea quinone tetrafluoroborate, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphonate, (2,3 - Dihydro-2-thioketo-3-benzoxazolyl)phosphonic acid diphenyl or the like.

The amount of the condensing agent to be added is preferably from 2 to 10 moles, more preferably from 2 to 3 moles, for the tetracarboxylic acid diester.

As the base, a tertiary amine such as pyridine or triethylamine can be used. The amount of the base to be added is preferably from 2 to 10 moles, more preferably from 2 to 4 moles, from the viewpoint of easy removal amount and easy availability of a high molecular weight body.

Further, in the above reaction, the reaction can be efficiently carried out by adding Lewis acid as an additive.

In terms of Lewis acid, lithium halide such as lithium chloride or lithium bromide is preferred. The amount of Lewis acid added is preferably 0.1 to 3.0 moles and more preferably 0.1 to 1.0 moles for the diamine component.

In the method for synthesizing the above three polyglycolates, in order to obtain a high molecular weight polyglycolate, the synthesis method of the above (1) or (2) is particularly preferable.

The solution of the polyphthalate obtained by the above method was poured into a poor solvent while being sufficiently stirred to precipitate a polymer. After several times of dissolution, precipitation, and washing with a poor solvent, it is dried at room temperature or by heating to obtain a purified polyphthalate powder.

The solvent is not particularly limited, and examples thereof include water, methanol, ethanol, isopropanol, hexane, butyl sarbuta, acetone, toluene, and the like, and methanol, ethanol, and isopropyl alcohol are preferred.

<polyimine]

The liquid crystal alignment agent of the present invention contains at least one polymer selected from the group consisting of the above polyimine precursor and polyimine.

In the case of polyimine, it may be a polyimine obtained by dehydrating a polylysine as a precursor of the above polyimine. In other words, a diamine component having a β-hydroxyester structure having a β-hydroxyester structure containing a diamine compound of the above formula (DA) or the above formula (DIA) is synthesized as a polyimine precursor. Polylysine is obtained by dehydration ring closure. The obtained polyimine is used for obtaining a polymer for a liquid crystal alignment film of the present invention, can be dissolved in a solvent or the like to constitute a liquid crystal alignment agent, and is cured by the coating film to provide a polyimine. Hardened film.

Further, in the polyimine contained in the liquid crystal alignment agent of the present invention, the dehydration ring closure ratio (the imidization ratio) of the valine group is not necessarily 100%, but It can be arbitrarily adjusted for visual use or purpose.

<Method for producing polyimine]

The method for carrying out the ruthenium imidization of poly-proline is exemplified by a catalyst which is obtained by directly heating a solution of poly-proline to be thermally imidized and adding a catalyst to a solution of poly-proline. .

The polyaminic acid used in the ruthenium imidization has a β-hydroxyester structure derived from a diamine compound having a β-hydroxyester structure used in the synthesis. For this reason, in the method of polyaminating poly-proline, the catalyst is imidized at a relatively low temperature by maintaining the structure of the β-hydroxyester inside the polyphthalic acid. It is better.

The ruthenium imide of poly-proline can be stirred by adding a basic catalyst and an acid anhydride to a solution of poly-proline, and stirring at -20 to 250 ° C, preferably 0 to 180 ° C. Implementation.

The amount of the basic catalyst is 0.5 to 30 moles, preferably 2 to 20 moles, of the prolyl group, and the amount of the acid anhydride is 1 to 50 moles, preferably 3 to the prolyl group. 30 moles.

Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferred because it has moderate alkalinity when the reaction proceeds.

Examples of the acid anhydride include anhydrous acetic acid, anhydrous trimellitic acid, and anhydrous pyromellitic acid. Among them, when anhydrous acetic acid is used, purification after completion of the reaction becomes easy, and it is preferable.

The rate of ruthenium imidization caused by the imidization of the catalyst, which can be adjusted by the amount of catalyst The reaction temperature and reaction time are controlled.

The above is the description of the components which can be contained in the liquid crystal alignment agent of the present invention, and the liquid crystal alignment agent of the present invention prepared by using these components will be described.

<Liquid alignment agent>

The liquid crystal alignment agent of the present invention is a coating liquid for forming a liquid crystal alignment film, which is a solution obtained by dissolving a resin component for forming a resin film in an organic solvent. Here, the resin component contains at least one polymer selected from the group consisting of the above-mentioned polyimine precursor and polyimine.

The content of the resin component is preferably from 1 to 20% by mass, more preferably from 3 to 15% by mass, still more preferably from 3 to 10% by mass.

In the present invention, all of the above-mentioned polymers may be used as the resin component, and other polymers other than these may be mixed. In this case, the content of the polymer other than the above polymer in the resin component is 0.5 to 15% by mass, preferably 1 to 10% by mass.

The organic solvent used in the liquid crystal alignment agent of the present invention is not particularly limited as long as it is an organic solvent capable of dissolving the resin component containing the polymer or the like. Specific examples thereof are as follows.

N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactone, 2-pyrrolidone, N-B Pyrrolidone, N-vinylpyrrolidone, dimethyl hydrazine, tetramethyl urea, pyridine, dimethyl hydrazine, hexamethylarylene, γ-butyrolactone, 3-methoxy-N , N-dimethylpropane decylamine, 3-ethoxy-N,N-dimethylpropane decylamine, 3-butoxy -N,N-dimethylpropane decylamine, 1,3-dimethyl-tetrahydroimidazolidone, ethyl pentanone, methyl fluorenone, methyl ethyl ketone, methyl isoamyl ketone, methyl Isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diethylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, and the like.

These may be used alone or in combination.

The liquid crystal alignment agent of the present invention may contain components other than the above. In this case, there are a solvent or a compound which improves uniformity of film thickness or surface smoothness when a liquid crystal alignment agent is applied, and a compound which improves adhesion of a liquid crystal alignment film and a substrate.

Specific examples of the solvent (lean solvent) which improves the uniformity of the film thickness or the surface smoothness include those described later.

For example, isopropanol, methoxymethylpentanol, methyl stilbene, ethyl serosol, butyl sirlo, methyl sarbuta acetate, ethyl serosu acetate , butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether , propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol Ethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol single B Acid monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl Isobutyl ether, diisobutylene, pentyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methyl cyclohexene, propyl ether, dihexyl ether, 1-hexyl Alcohol, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, acetic acid Propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl 3-ethyloxypropionate, 3-methoxypropionic acid Base ester, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid propyl ester, 3-methoxypropionic acid butyl ester, 1-methoxy-2-propanol Alcohol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1 -monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2-(2-ethoxypropoxy)propanol, methyl lactate, A solvent having a low surface tension such as ethyl lactate, n-propyl lactate, n-butyl lactate or isoamyl lactate.

These poorly soluble solvents may be used alone or in combination of a plurality of them. When the solvent is used, it is preferably from 5 to 80% by mass, more preferably from 20 to 60% by mass, based on the total amount of the solvent contained in the liquid crystal alignment agent.

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

More specifically, Eftop (registered trademark) EF301, EF303, EF352 (manufactured by TOHKEM PRODUCTS), Megafac (registered trademark) F171, F173, R-30 (manufactured by Dainippon Ink Co., Ltd.), Florad FC430, FC431 (made by Sumitomo 3M), AashiGuard (registered trademark) AG710, Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106 (made by Asahi Glass Co., Ltd.).

The use ratio of the surfactant is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of the resin component contained in the liquid crystal alignment agent.

Specific examples of the compound which enhances the adhesion between the liquid crystal alignment film and the substrate include a functional decane-containing compound or an epoxy group-containing compound to be described later.

For example, 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 2-aminopropyltrimethoxydecane, 2-aminopropyltriethoxydecane, N- (2-Aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, 3-ureidopropyl Trimethoxy decane, 3-ureidopropyl triethoxy decane, N-ethoxycarbonyl-3-aminopropyltrimethoxy decane, N-ethoxycarbonyl-3-aminopropyl three Ethoxy decane, N-triethoxydecyl propyl triethylene triamine, N-trimethoxydecyl propyl triethylene triamine, 10-trimethoxydecyl-1,4,7-triazo Heteroane, 10-triethoxydecyl-1,4,7-triazanonane, 9-trimethoxydecyl-3,6-diazadecyl acetate, 9-triethyl Oxyalkylalkyl-3,6-diazaindolyl acetate, N-benzyl-3-aminopropyltrimethoxydecane, N-benzyl-3-aminopropyltriethoxy Baseline, N-phenyl-3-aminopropyltrimethoxydecane, N-phenyl-3-aminopropyltriethoxydecane, N-bis(oxyethylene)-3-aminopropyl Trimethoxydecane, N-bis(oxyethylene)-3-amino Propyltriethoxydecane, ethylene glycol diepoxypropyl ether, polyethylene glycol diepoxypropyl ether, propylene glycol diepoxypropyl ether, tripropylene glycol diepoxypropyl ether, polypropylene glycol bicyclo Oxypropyl propyl ether, neopentyl glycol diepoxypropyl ether, 1,6-hexanediol diepoxypropyl ether, glycerol diepoxypropyl ether, 2,2- Dibromo neopentyl glycol diepoxypropyl ether, 1,3,5,6-tetraepoxypropyl-2,4-hexanediol, N,N,N',N',-tetraepoxy Propyl-m-xylenediamine, 1,3-bis(N,N-diepoxypropylaminomethyl)cyclohexane, N,N,N',N',-tetraepoxypropyl -4,4'-diaminodiphenylmethane, and the like.

When a compound which can improve the adhesion to the substrate is used, the amount of the resin component contained in the liquid crystal alignment agent is preferably from 0.1 to 30 parts by mass, more preferably from 1 to 20, based on 100 parts by mass of the resin component contained in the liquid crystal alignment agent. Parts by mass. When the amount is less than 0.1 part by mass, the effect of improving the adhesion cannot be expected. When the amount is more than 30 parts by mass, the liquid crystal alignment property of the formed liquid crystal alignment film is lowered.

In addition to the above, the liquid crystal alignment agent of the present invention may be added with a dielectric for the purpose of changing the electrical properties such as the dielectric constant or the conductivity of the liquid crystal alignment film, without impairing the effects of the present invention. A body or a conductive material may be added, or a crosslinkable compound for the purpose of improving the hardness or density of the film as a liquid crystal alignment film may be added.

Next, a liquid crystal alignment film of the present invention and a liquid crystal display element having the liquid crystal alignment film will be described.

<Liquid alignment film and liquid crystal display element>

The liquid crystal alignment agent of the present invention contains at least one polymer selected from the group consisting of a polyimide precursor and a polyimine, and the polyimine precursor and the polyimine are used as described above. A diamine compound having a β-hydroxyester structure of a diamine compound such as the formula (DA) or the above formula (DIA) is a component of a diamine component which is an essential component. a liquid crystal alignment agent, preferably applied to a substrate It was previously filtered, and then coated, pre-baked and dried, and then fired to form a polyimide film.

In the case of heating and firing, the polyimine precursor and/or polyimine contained in the liquid crystal alignment agent of the present invention have a β-hydroxyester structure in the molecule, and a photoreactive double bond can be formed in the molecule.

In the liquid crystal alignment agent of the present invention, when the coating film of the liquid crystal alignment agent is heated and fired to carry out the oxime imidization reaction of the polyimide precursor component, the β-hydroxyester structure can be simultaneously carried out. The dehydration reaction is carried out to introduce a photoreactive double bond into the formed polyimide film.

Further, in the liquid crystal alignment agent of the present invention containing a polyimine, when a coating film obtained by coating and drying a liquid crystal alignment agent is heated and fired to form a polyimide film, the β-hydroxyester structure can be simultaneously formed. The dehydration reaction is carried out to introduce a photoreactive double bond into the polyimide film.

As described above, the liquid crystal alignment agent of the present invention can be heated and fired by coating a film obtained by drying a liquid crystal alignment agent, and a double bond can be introduced while forming a polyimide film, and can be polymerized. A photoreactive site such as a cinnamate structure is introduced into the imide film. As a result, photoalignment can be achieved in a liquid crystal alignment film using a polyimide film formed of a liquid crystal alignment agent of the present invention containing a polyimide precursor and/or polyimine.

When the liquid crystal alignment agent of the present invention is applied to a substrate, a substrate having high transparency can be used as the substrate to be used.

For the substrate, for example, a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used in addition to the glass substrate.

In the manufacture of a liquid crystal display element, the liquid crystal alignment agent of the present invention is used. In the case of using a substrate on which an ITO (Indium Tin Oxide) electrode for liquid crystal driving or the like is formed, a liquid crystal alignment film is formed. Further, when a reflective liquid crystal display device is manufactured, an opaque substrate such as a germanium wafer can be used as the substrate on the single side, and a material such as aluminum that reflects light can be used as the electrode.

The coating method for applying the liquid crystal alignment agent to the substrate is not particularly limited, and industrially, screen printing, lithography, flexographic printing, inkjet printing, and the like are common. Examples of other coating methods include a dipping method, a roll coating method, a slit coating method, a spin coating method, and a spray method, and these can be used depending on the purpose.

The liquid crystal alignment agent of the present invention has good coatability even when the above coating method is used.

Although the drying step by pre-baking after coating the liquid crystal alignment agent is not necessary, the time from the application to the heating and firing may be due to the substrate, not necessarily, or after coating. When the heating and baking are not performed immediately, it is preferred to include a drying step. The drying by the prebaking is preferably performed by evaporating the solvent to such an extent that the shape of the coating film is not deformed by substrate transportation or the like. Further, in the β-hydroxyester structure of the polyamidene precursor and/or polyimine contained in the liquid crystal alignment agent, it is preferably carried out in a temperature range in which no dehydration reaction occurs.

The drying means by the prebaking is not particularly limited. For the specific example, it is preferred to dry it on a hot plate at 50 to 120 ° C, preferably 80 to 120 ° C for 0.5 to 30 minutes, preferably 1 to 5 minutes.

The baking of the substrate coated with the liquid crystal alignment agent can be carried out at a temperature of 120 to 350 ° C by a heating means such as a hot plate, a heat cycle type oven, or an IR (infrared) type oven. The firing temperature is a temperature suitable for the formation of the polyimide film, and the polyhydrazide precursor contained in the liquid crystal alignment agent and/or the β-hydroxy ester structure of the polyimide may be dehydrated. The temperature at which the reaction will proceed. The firing temperature is preferably from 140 to 300 ° C, more preferably from 180 to 250 ° C. However, it is preferably more than 10 ° C higher than the heat treatment temperature required for the production step of the liquid crystal display element and the curing of the sealant. The temperature is used for firing.

When the thickness of the polyimide film obtained by baking is too thick, it is disadvantageous in the power-consuming surface of the liquid crystal display device. If the thickness of the liquid crystal display device is too small, the reliability of the liquid crystal display device is lowered. Therefore, it is preferably 10 to 200 nm, more preferably 50~100nm.

The liquid alignment film of the present invention can be formed by performing photoalignment treatment on the polyimide film formed on the substrate as described above.

The method of the photo-alignment treatment is not particularly limited, and it is preferable to use a polarized ultraviolet ray to obtain a uniform liquid crystal alignment. At this time, the method of irradiating the polarized ultraviolet rays is not particularly limited. For example, the substrate on which the polyimide film is formed can be irradiated with ultraviolet rays that are polarized by passing through the polarizing plate in a certain direction. Further, the incident angle of the polarized ultraviolet light may be changed to be irradiated twice or more. Further, if polarized light is substantially obtained, the unpolarized ultraviolet light can be irradiated by inclining a predetermined angle from the normal line of the substrate.

The wavelength of ultraviolet rays used is generally 100 to 400 nm, and preferably ultraviolet rays in the range of 250 to 370 nm are used. It is preferable to select the optimum wavelength according to the type of polyimine used, such as a filter.

Further, the amount of ultraviolet rays to be irradiated is generally in the range of several mJ/cm ² to several J/cm ² , preferably ⁵ mJ/cm ² to 500 mJ/cm ² . In particular, if it is considered that the industrial productivity or the increase in the amount of irradiation may cause a decrease in the voltage holding ratio of the liquid crystal display element to be subsequently produced, it may be selected depending on the type of polyimine used. The necessary amount of good alignment is preferred.

The liquid crystal alignment agent of the present invention can form a vertically aligned photoalignment liquid crystal alignment film on a substrate by the above method. The formed liquid crystal alignment film is photo-alignable, and reduces the dust problem caused by rubbing the liquid crystal alignment film or the damage attached to the liquid crystal alignment film in the rubbing treatment as a conventional alignment treatment method. The display quality of the display element is reduced.

In the liquid crystal alignment agent of the present invention, a liquid crystal alignment film is formed on a substrate by the above method, and then a substrate having the liquid crystal alignment film is used, and a liquid crystal display element can be produced by a known method.

An example of the manufacture of a liquid crystal display element will be described below.

A pair of substrates in which a liquid crystal alignment film of a vertical alignment type is formed by using the liquid crystal alignment agent of the present invention is prepared. Next, the spacers preferably having a thickness of 1 to 30 μm, more preferably 2 to 10 μm, are placed, and the projection directions of the optical axes of the polarized ultraviolet rays irradiated on the respective substrates are, for example, arranged in antiparallel, and the surroundings are sealed. The agent is fixed. Next, liquid crystal is injected between the substrates and then sealed. The method of encapsulating the liquid crystal is not particularly limited, and it can be exemplified that it will be produced. A vacuum method in which a liquid crystal cell is decompressed and then injected into a liquid crystal, a dropping method in which a liquid crystal is dropped, and sealing is performed.

The liquid crystal display element produced has a liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention, and the liquid crystal display element can constitute a VA mode liquid crystal display element.

The liquid crystal display element of the present invention does not have a deterioration in display quality due to scratches of the liquid crystal alignment film, etc., and has excellent display quality, and further has high reliability.

[Examples]

The following examples are given to illustrate the invention in more detail. Further, the invention is not limited by the above explained.

The structures and abbreviations of the main compounds used in the examples and comparative examples are as follows.

Further, the diamine compound (DA-1-1) is an example of a diamine compound represented by the above formula (DA-1). Further, the diamine compound (DAM-1) is a conventional diamine compound having a cinnamic acid ester structure in the molecule.

<Structure and Abbreviation>

<tetracarboxylic acid derivative>

CBDA: 1,2,3,4-cyclobutane tetracarboxylic dianhydride

PMDA: pyromellitic dianhydride

<Diamine compound>

DA-1-1: 3,5-diaminobenzyl-3-(4-(decyloxy)phenyl)-3-hydroxypropionate

DAM-1: (E)-3,5-diaminobenzyl-3-(4-(decyloxy)phenyl)acrylate

DMAP: N,N'-dimethyl-4-aminopyridine

<Solvent>

NMP: N-methyl-2-pyrrolidone

BC: Butyl Cyrus

DMF: N,N'-dimethylformamide

In Examples 1 to 6, the synthesis of the compounds [2] to [7] was carried out according to the exemplified reaction formulas (1) to (6). The obtained compound [7] is used for the synthesis of a diamine compound (DA-1-1).

<Example 1>

Addition of 4-hydroxybenzoic acid ethyl [1] (19.9 g, 0.120 mol), 1-bromodecane (22.1 g, 0.100 mol), potassium carbonate (27.6 g, 0.200 mol) and dimethylformamide 120 g The mixture was stirred in a nitrogen atmosphere to a four-necked flask, and the temperature was raised to 80 °C. After stirring for 4 hours, it was confirmed by ¹ H-NMR (nuclear magnetic resonance) method that 1-bromodecane in the reaction liquid disappeared. Thereafter, the solvent was distilled off, and a water washing operation was performed with toluene and a 2 equivalent NaOH aqueous solution to remove the aqueous layer. The obtained organic layer was washed twice with water, and the obtained organic layer was dried over anhydrous magnesium sulfate. After drying, the magnesium sulfate was removed by filtration, and the obtained organic layer was evaporated to vacuo to yield compound [2] (yield: 27.7 g, 0.090 mol, yield: 90.3%).

The structure of the compound [2] was confirmed by ¹ H-NMR analysis to obtain the following spectral data.

¹ H-NMR (solvent; CDCl ₃ ): δ 7.98 (d, 2H, J = 10.8 Hz), 6.89 (d, 2H, J = 10.8 Hz), 4.34 (q, 2H, J = 7.2 Hz), 3.99 (t, 2H, J = 6.8 Hz), 1.82-1.75 (m, 2H), 1.47-1.26 (m, 17H), 0.89 (t, 3H, J = 6.8 Hz).

<Example 2>

The compound [2] (10.8 g, 0.0354 mol), potassium hydroxide (10.0 g), 118 g of ethanol and 20.0 g of water were added to a four-necked flask, and stirred at room temperature for 3 days. Thereafter, the mixture was further heated to 80 ° C and stirred for 1 hour. The solution was cooled, and the disappearance of the raw material was confirmed by HPLC (High Performance Liquid chromatography). Thereafter, 18 ml of 12 equivalents of an aqueous hydrochloric acid solution was placed in an ice bath and further stirred. Next, 300 g of water was added to precipitate crystals. After crystallization from the filtrate, the crystals were dried to give the compound [3] (yield: 9.05 g, 0.0325 mol, yield: 91.8%).

The structure of the compound [3] was confirmed by ¹ H-NMR analysis to obtain the following spectral data.

¹ H-NMR (solvent; CDCl ₃ ): δ 8.05 (d, 2H, J = 10.8 Hz), 6.93 (d, 2H, J = 10.8 Hz), 4.03 (t, 2H, J = 6.8 Hz), 1.84 -1.77 (m, 2H), 1.48-1.28 (m, 14H), 0.89 (t, 3H, J = 6.8 Hz).

<Example 3>

Compound [3] (52.2 g, 0.188 mol), tetrahydrofuran (200 ml) and DMF (5.19 g) were added to a four-necked flask, and chloroform (39.5 g, 0.311 mol) was slowly dripped in the solution. After stirring at room temperature for 4 hours, the solvent was distilled off to obtain a crude product of the acid chlorided material of compound [4]. Further, a four-necked flask of Meldrum's acid (21.6 g, 0.150 mol), N,N-dimethyl-4-aminopyridine (36.7 g, 0.300 mol) and dichloromethane 250 ml was added in advance. In the above, 120 ml of dichloromethane in which the crude product of the compound [4] was dissolved was slowly dropped using a syringe, and stirred under ice bath for 1 hour. After that, it was stirred at room temperature for 15 hours. After completion of the reaction, 300 ml of chloroform and 300 ml of a 2 N aqueous hydrochloric acid solution were added, and the alkali in the solution was dissolved in water as a salt to be removed, and the organic layer was washed three times with pure water. The obtained organic layer was dried over anhydrous magnesium sulfate, and then filtered and evaporated to ethylamine.

The structure of the compound [5] was confirmed by ¹ H-NMR analysis to obtain the following spectral data.

¹ H-NMR (solvent; CDCl ₃ ): δ 8.09-8.03 (m, 2H), 6.98-6.91 (m, 2H), 4.03 (q, 2H, J = 6.8 Hz), 3.64 (s, 1H,) , 1.86-1.77 (m, 8H), 1.48-1.24 (m, 14H), 0.89 (t, 3H, J = 6.8 Hz).

<Example 4>

Compound [5] (72.7 g), 3,5-dinitrobenzyl alcohol (29.7 g, 0.150 mol) and 450 g of dehydrated acetonitrile were added to a four-necked flask, and the mixture was stirred under heating at 70 °C. After stirring for 2 hours, it was confirmed by HPLC that the disappearance of the raw material and the end of the gas (carbon dioxide-containing gas) were completed, and then the solvent was concentrated. 450 ml of methanol was added to the concentrate to precipitate crystals, and the crystals were removed by filtration. The obtained crystal was purified by column chromatography of ruthenium dioxide colloid (solvent solvent: hexane: ethyl acetate = 4:1 (volume ratio)) to obtain the objective compound [6] (yield 30.8 g, 0.0615). Mol, yield 41.0%).

The structure of the compound [6] was confirmed by ¹ H-NMR analysis to obtain the following spectral data.

¹ H-NMR (solvent; CDCl ₃ ): δ 8.99 (s, 1H), 8.54 (s, 2H), 7.89 (d, 2H, J = 10.8 Hz), 6.92 (d, 2H, J = 10.8 Hz) , 5.39 (s, 2H), 4.09 (s, 2H), 4.02 (t, 2H, J = 6.4 Hz), 1.85-1.78 (m, 2H), 1.50-1.28 (m, 14H), 0.88 (t, 3H) , J = 6.8Hz).

<Example 5>

Compound [6] (29.9 g, 0.0597 mol), platinum gold powder (3%) 7.54 g and tetrahydrofuran 260 g were placed in a four-necked flask, and stirred at room temperature for 21 hours under a hydrogen atmosphere. The disappearance of the compound [6] as a raw material was confirmed by HPLC, and the main product was confirmed to be the object of interest by ¹ H-NMR. Thereafter, the reaction liquid was filtered to remove platinum gold powder. The obtained filtrate was concentrated, and the slurry was washed once with 300 ml of methanol. Next, the crystals were collected by filtration and dried to give compound [7] (yield 14.1 g, 0.0320 mol, yield 53.6%).

The structure of the compound [7] was confirmed by ¹ H-NMR analysis to obtain the following spectral data.

¹ H-NMR (solvent; CDCl ₃ ): δ 7.90 (d, 2H, J = 8.8 Hz), 6.92 (d, 2H, J = 8.8 Hz), 6.04-5.96 (m, 2H), 5.96 (s, 1H), 5.00 (s, 2H), 4.03-3.99 (m, 4H), 3.57-3.49 (broad, 4H), 1.82-1.77 (m, 2H), 1.47-1.28 (m, 14H), 0.88 (t, 3H, J = 6.8Hz).

<Example 6>

Compound [7] (11.6 g, 0.0263 mol), 50.0 g of tetrahydrofuran and 50.0 g of ethanol were added to a four-necked flask, and the mixture was cooled to 0 °C. Thereafter, NaBH ₄ (1.00 g, 0.0264 mol) was added and stirred for 15 minutes, and then additional NaBH ₄ (0.384 g, 0.0102 mol) was gradually added thereto, followed by stirring for 40 minutes. After confirming that the compound [7] as a raw material was stopped by HPLC, 18 ml of tetrahydrofuran and a saturated aqueous solution of ammonium chloride were slowly added to stop the reaction (quenching quench). It was confirmed by the thermometer inserted into the reaction liquid that the heat generation from the reaction liquid disappeared, and 400 ml of tetrahydrofuran and 300 mL of a saturated aqueous ammonia solution were further added to separate into two layers of an organic layer and an aqueous layer. After separating the two layers, the organic layer was dried over anhydrous magnesium sulfate, and then magnesium sulfate was filtered. The obtained organic layer was evaporated under reduced pressure to give a solvent. The obtained crystals were washed once with a slurry of 100 g of methanol, and the crystals were filtered and dried to give a diamine compound (DA-1-1) (yield: 5.93 g, 0.0134 mol, yield: 51.0%).

The structure of the diamine compound (DA-1-1) was confirmed by ¹ H-NMR analysis to obtain the following spectral data.

¹ H-NMR (CDCl ₃ ): δ 7.27 (d, 2H, J = 10.8 Hz), 6.87 (d, 2H, J = 10.8 Hz), 6.04 (s, 2H), 5.97 (s, 1H), 5.11 -5.08 (m, 1H), 4.96 (S, 2H), 3.94 (t, 2H, J = 6.8 Hz), 3.56 (broad, 4H), 3.15 (broad, 1H), 2.85-2.70 (m, 2H), 1.80-1.73 (m, 2H), 1.46-1.27 (m, 14H), 0.88 (t, 3H, J = 6.8 Hz).

<Example 7>

CBDA (0.471 g, 2.40 mmol) and a diamine compound (DA-1-1) (1.107 g, 2.5 mmol) were mixed with NMP (8.94 g), and reacted at room temperature for 10 hours to obtain polylysine. Solution. NMP (7.89 g) and BC (7.89 g) were added to the polyamic acid solution, and the mixture was diluted to 6% by mass. Then, the mixture was stirred at room temperature for 5 hours to obtain a liquid crystal alignment agent (A1). The polyamic acid contained in the liquid crystal alignment agent (A1) had a number average molecular weight of 6,700 and a weight average molecular weight of 24,400.

<Example 8>

PMDA (0.518 g, 2.40 mmol) and DA-1-1 (1.107 g, 2.5 mmol) were mixed with NMP (10.83 g), and reacted at room temperature for 10 hours to obtain a polyaminic acid solution. To the polyamic acid solution, NMP (8.12 g) and BC (8.12 g) were added and diluted to 6 mass%. Next, the liquid crystal alignment agent (A2) was obtained by stirring at room temperature for 5 hours. The number average molecular weight of the polyamic acid contained in the liquid crystal alignment agent (A2) was 8,500, and the weight average molecular weight was 24,500.

<Comparative Example 1>

CBDA (0.577 g, 2.9 mmol) and DAM-1 (1.274 g, 3.0 mmol) were mixed in NMP (10.48 g), and allowed to react at room temperature for 10 hours. A polylysine solution was obtained. NMP (9.25 g) and BC (9.25 g) were added to the polyamic acid solution, and the mixture was diluted to 6 mass%. Then, the liquid crystal alignment agent (A3) of the comparative example was obtained by stirring at room temperature for 5 hours. The number average molecular weight of the polyamic acid contained in the liquid crystal alignment agent (A3) was 9,700, and the weight average molecular weight was 19,200.

The measurement of the molecular weight of the polylysine obtained in Example 7, Example 8 and Comparative Example 1 was carried out as follows.

[Measurement of molecular weight]

The measurement was carried out in the following manner using a room temperature colloid-impregnated color layer analysis (GPC) apparatus (SSC-7200) manufactured by SENSHU Scientific Co., Ltd., and a pipe column (KD-803, KD-805) manufactured by Shodex Co., Ltd.

Column temperature: 50 ° C

Dissolution: N,N'-dimethylformamide (lithium bromide-hydrate (LiBr.H ₂ O) as an additive 30 mmol/L (liter), phosphoric acid. Anhydrous crystal (o-phosphoric acid) 30 mmol/L , tetrahydrofuran (THF) system 10ml / L)

Flow rate: 1.0 mL / min

Standard sample for the calibration curve: TSK standard polyethylene oxide (molecular weight of about 9,000,000, 150,000, 100,000, and 30,000) manufactured by TOSOH Co., Ltd., and polyethylene glycol (molecular weight of about 12,000, 4000, and 1000) manufactured by Polymer Laboratories. .

<Example 9>

Regarding the use of the liquid crystal alignment agent (A1) obtained in Example 7 The cured film was subjected to measurement of ultraviolet (UV) absorption spectrum and evaluation of coatability as follows.

Further, the cured film (polyimine film) formed by using the liquid crystal alignment agent (A1) obtained in Example 7 was irradiated in an amount of 0 mJ, 20 mJ, 50 mJ, or 100 mJ by the following method. Each liquid crystal cell was evaluated for pretilt angle.

[Measurement of ultraviolet (UV) absorption spectrum]

The liquid crystal alignment agent (A1) obtained in Example 7 was spin-coated on a quartz substrate, dried on a hot plate at 80 ° C for 90 seconds, and then fired in a hot air circulating oven at 200 ° C for 30 minutes to form a film thickness of 100 nm. Polyimine film. In this case, the substrate was irradiated with a UV absorption spectrometer (UV-3600) manufactured by Shimadzu Corporation, and then baked in a hot air circulating oven at 200 ° C for 30 minutes (also referred to as "before firing") and after. (Also known as "after firing"), the UV absorption spectrum was measured.

Fig. 1 shows the measurement results of the UV absorption spectrum before and after firing.

Next, the substrate was fired in a hot air circulating oven at 200 ° C for 30 minutes, and the substrate was irradiated with linear polarized light of 300 mJ and 1 J (1000 mJ) at an irradiation intensity of 11.0 mW/cm ^-2 at 313 nm. The directions of the incident rays are each inclined by 40° to the normal direction of the substrate. This linear polarized light was passed through a 313 nm band pass filter after the ultraviolet light of the high pressure mercury lamp was passed through a 313 nm polarizing plate. Further, the UV absorption spectrum was measured by the above method using a substrate irradiated with linear polarized light of 300 mJ and 1 J (1000 mJ). The measurement results of the UV absorption spectrum are shown in Fig. 3 .

In Fig. 3, as described above, the obtained UV absorption spectrum was marked "300 mJ", which is shown in Fig. 3 together with the UV absorption spectrum after firing shown in Fig. 1.

Further, the substrate used for the measurement of the UV absorption spectrum after the firing shown in Fig. 1 was not subjected to the linear polarized light irradiation as described above. Therefore, when the irradiation amount corresponding to the linearly polarized light is 0 mJ, it is marked as "0 mJ" in FIG.

[Evaluation of coating properties]

The liquid crystal alignment agent (A1) obtained in Example 7 was spin-coated on the ITO electrode surface of a glass substrate with an ITO electrode formed of an ITO film, and dried on a hot plate at 80 ° C for 90 seconds to observe coating. surface. When the coating surface was uneven or the film was ejected as "poor", and the uniformity of no ejection or unevenness was described as "good", the coating property of the liquid crystal alignment agent (A1) was evaluated.

[Production of liquid crystal cell]

Using the liquid crystal alignment agent (A1) obtained in Example 7, a liquid crystal cell as a liquid crystal display element was produced as follows.

The liquid crystal alignment agent (A1) obtained in Example 7 was spin-coated on the ITO electrode surface of the glass substrate with the ITO electrode formed of the ITO film, and dried on a hot plate at 80 ° C for 90 seconds, at 200 ° C. The hot air circulating oven was fired for 30 minutes to form a polyimide film having a film thickness of 100 nm.

To the substrate, a linear polarized light of 20 mJ of 313 nm having an irradiation intensity of 11.0 mW/cm ^-2 was irradiated. In the measurement of the UV absorption spectrum described above, the direction of the incident light was inclined by 40° with respect to the normal direction of the substrate, similarly to the case where the linearly polarized light was irradiated. This linear polarized light was passed through a 313 nm band pass filter to the ultraviolet light of the high pressure mercury lamp, and then modulated by a 313 nm polarizing plate.

Two sheets of the above-mentioned substrates were prepared, and a bead spacer of 6 μm was spread on the liquid crystal alignment film of one of the substrates, and then a sealant was printed thereon. Then, the liquid crystal alignment of the two substrates was faced so that the projection direction of the optical axis of the linearly polarized light toward each substrate was pressed in anti-parallel, and it took 105 minutes at 150 ° C to form a sealant (XN, Xie Li Chemical Co., Ltd.) -1500T) Thermal hardening. In this empty cell, a negative liquid crystal having a negative dielectric anisotropy (manufactured by Merck Co., Ltd., MLC-6608) was injected by a reduced pressure injection method to prepare a liquid crystal cell having a linear polarization of 20 mJ.

Next, a liquid crystal cell in which the linearly polarized light was irradiated at 50 mJ was produced in the same manner as described above except that the amount of the linearly polarized light was 50 mJ.

Further, in addition to the irradiation amount of the linearly polarized light of 100 mJ, a liquid crystal cell having an irradiation amount of linear polarized light of 100 mJ was produced in the same manner as described above.

Further, in addition to the fact that the linearly polarized light was not irradiated, the liquid crystal cell in which the linearly polarized light was irradiated at 0 mJ was produced in the same manner as described above.

[Evaluation of pretilt angle]

The liquid crystal cell having different irradiation amounts of linearly polarized light was used to measure the pretilt angle in the liquid crystal alignment. The pretilt angle was measured using Axo Metrix's "Axo Scan" by Mueller Matrix (Mueller). Matrix) method to implement.

In the measurement result of the pretilt angle, the liquid crystal cell system pretilt angle of the linearly polarized light irradiation amount of 20 mJ was 89.1 degrees, and the liquid crystal molecules were aligned only slightly in the normal direction of the substrate surface in the normal direction of the substrate.

On the other hand, the liquid crystal cell system pretilt angle of the linear polarized light irradiation amount of 0 mJ is 90.0 degrees, and the liquid crystal molecule liquid crystal molecules are aligned toward the normal direction of the substrate, and are not obliquely aligned.

The above evaluation results are shown in Table 1 together with the results of Example 10 and Comparative Example 2.

<Example 10>

In the same manner as in Example 9, the cured film obtained by using the liquid crystal alignment agent (A2) obtained in Example 2 was subjected to measurement of ultraviolet (UV) absorption spectrum and evaluation of applicability.

Further, a liquid crystal cell was produced in the same manner as in Example 9 except that the liquid crystal alignment agent (A1) was changed to the liquid crystal alignment agent (A2), and the pretilt angle was measured.

<Comparative Example 2>

In the same manner as in Example 9, the cured film obtained by using the liquid crystal alignment agent (A3) obtained in Comparative Example 1 was subjected to measurement of ultraviolet (UV) absorption spectrum and evaluation of applicability.

Further, a liquid crystal cell was produced in the same manner as in Example 9 except that the liquid crystal alignment agent (A1) was changed to the liquid crystal alignment agent (A3). The measurement of the pretilt angle is performed.

Fig. 2 shows an ultraviolet absorption spectrum of a cured film composed of a polyimide which is formed using the liquid crystal alignment agent (A3) of Comparative Example 1.

From the results shown in Fig. 1, it was confirmed that the cured film formed by using the liquid crystal alignment agent (A1) of Example 7 was formed into a polyimide film by firing, and a new absorption was generated in the ultraviolet region. The absorption of this ultraviolet region is comparable to the UV spectrum of the cured film formed using the liquid crystal alignment agent (A3) of Comparative Example 1 shown in Fig. 2, and can be interpreted as a double bond structure formed from the cured film.

Further, as shown in Fig. 3, in the cured film formed by using the liquid crystal alignment agent (A1) of Example 7, by irradiating ultraviolet rays as linearly polarized light, it was confirmed that the absorbance in the ultraviolet region was lowered. This reason can be explained by the fact that part of the double bond structure formed in the cured film disappears by irradiation with ultraviolet rays.

From the results shown in Fig. 1, it was confirmed that the liquid crystal alignment agent of the present invention forms a polyimide film at the same time as firing, and generates new absorption in the ultraviolet region. The absorption of this ultraviolet region can be explained by the double bond structure formed from the polyimide film.

Further, as shown in Fig. 3, the polyimide film formed by the liquid crystal alignment agent of the present invention can be confirmed by irradiation of ultraviolet rays which are linearly polarized, and it is confirmed that the absorbance of the newly generated ultraviolet region is lowered. It can be interpreted as being irradiated by the ultraviolet light of the linearly polarized light, and a part of the double bond structure formed in the polyimide film disappears.

As is clear from the results shown in Table 1, the polyimide film formed by the liquid crystal alignment agent of the present invention is directly used without being irradiated with linearly polarized light, and the ruthenium constitutes a liquid crystal alignment in which liquid crystal molecules are aligned in the normal direction of the substrate. membrane.

Further, the polyimide film formed by the liquid crystal alignment agent of the present invention can be formed by irradiation of linearly polarized light to form a vertically aligned light in which liquid crystal molecules are slightly inclined from one direction of the substrate in the normal direction of the substrate surface. Reactive liquid crystal alignment film.

The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can be suitably used as a liquid crystal alignment film of a VA liquid crystal display element, and it is also confirmed that it is excellent in the coating property of a conventional subject. Further, it is known that it can be used as a liquid crystal alignment film of a vertical alignment type photoreactivity which is excellent in uniformity.

[Industry use possibility]

The liquid crystal alignment agent of the invention can provide a coating property A liquid crystal alignment element having a VA type which has excellent display quality can be manufactured with high productivity, and is also excellent in the liquid alignment film which does not require a light-aligning type. In other words, the liquid crystal display device of the present invention can be applied to a large-sized liquid crystal TV or a liquid crystal display element for mobile use such as a smart phone that displays high-definition video.

In addition, Japanese Patent Application No. 2012-064186, filed on March 21, 2012, and Japanese Patent Application No. 2012-064187, filed on March 21, 2012, The entire content is taken as the disclosure of the specification of the present invention.

Claims (14)

A liquid crystal alignment agent characterized by comprising at least one polymer selected from the group consisting of a polyimide precursor having a β-hydroxyester structure and a polyimide having a β-hydroxyester structure. The liquid crystal alignment agent according to claim 1, wherein the polyimine precursor having a β-hydroxyester structure and the polyazonia having a β-hydroxyester structure are a diamine compound having a β-hydroxyester structure. Income. The liquid crystal alignment agent of claim 2, wherein the diamine compound has a structure represented by the following formula (HE-1). (In the formula (HE-1), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring having 8 to 10 atoms. And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms. The liquid crystal alignment agent of claim 2 or 3, wherein the diamine compound has a structure represented by the following formula (HE-2), (In the formula (HE-2), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring having 8 to 10 atoms. And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms; X ₂ represents a single bond or is represented by an ether, an ester or a decylamine. And at least one divalent bond group selected from the group consisting of urethanes; X ₃ represents a linear alkyl group having 3 to 20 carbon atoms or an alicyclic skeleton having 4 to 40 carbon atoms A monovalent organic group, except that the hydrogen atom of the alkyl group may be substituted with a fluorine atom). The liquid crystal alignment agent of claim 2 or 3, wherein the diamine compound is a compound represented by the following formula (DA), (In the formula (DA), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring system having 8 to 10 atoms; And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms; X ₂ represents a single bond or an ether, an ester, a decylamine, and At least one divalent bond group selected from the group consisting of urethanes; X ₃ represents a monovalent chain having a linear alkyl group having 3 to 20 carbon atoms or an alicyclic skeleton having 4 to 40 carbon atoms The organic group, except that the hydrogen atom of the alkyl group may be substituted with a fluorine atom; X _{4 is} represented by a single bond, a methylene group or a C 2 to 6 alkyl group; however, the alkyl group may be substituted with a hydroxyl group; X ₅ represents a single bond, an oxygen atom, *-OCO- or *-OCH ₂ - (except that the bond bond with "*" is bonded to X ₄ ), but when X ₄ is a single bond, X ₅ is single bond). A liquid crystal alignment film obtained by the liquid crystal alignment agent according to any one of claims 1 to 5. A liquid crystal display element having the liquid crystal alignment film of claim 6. A diamine compound characterized by having the structure represented by the following formula (HE-1), (In the formula (HE-1), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring having 8 to 10 atoms. And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms. A diamine compound according to claim 8, which has a structure represented by the following formula (HE-3), (In the formula (HE-3), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring having 8 to 10 atoms. And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms; X ₂ represents a single bond or is represented by an ether, an ester or a decylamine. And at least one divalent bond group selected from the group consisting of urethanes; X ₆ represents a single bond or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; X ₇ represents A single bond or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; and X ₈ represents a linear alkyl group having 1 to 20 carbon atoms. A diamine compound according to claim 8 or 9, which is represented by the following formula (DIA), (In the formula (DIA), X ₁ represents a monocyclic ring having 5 or 6 atoms, a contiguous monocyclic ring having 5 or 6 atoms, and a bicyclic ring system having 8 to 10 atoms; And an unsubstituted or substituted carbocyclic or heterocyclic aromatic group selected from the group consisting of a tricyclic ring system having 13 or 14 atoms; X ₂ represents a single bond or an ether, an ester, a decylamine, and At least one divalent bond group selected from the group consisting of urethanes; X ₆ represents a single bond or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; and X ₇ represents a single bond Or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; X ₈ represents a linear alkyl group having 1 to 20 carbon atoms; and X ₉ represents a single bond, a methylene group or a carbon number of 2 to 6 An alkyl group, except that the alkyl group may be substituted with a hydroxyl group; X ₁₀ represents a single bond, an oxygen atom, *-OCO-, *-OCH ₂ -, *-COO-, *-NHCO- or *-CONH- ( However, the key with "*" is linked to X ₉ ), but when X ₉ is a single key, X ₁₀ is a single key). A polymer having a β-hydroxyester structure in the molecule, which is obtained by using the diamine compound according to any one of claims 8 to 10. A liquid crystal alignment agent comprising the polymer of claim 11. A liquid crystal alignment film obtained by the liquid crystal alignment agent of claim 12. A method for producing a diamine compound, which is a method for producing a diamine compound represented by the following formula (DIA), which comprises the step of: a compound represented by the following formula (C-1) and rice a reaction of Meldrum's acid to obtain a compound represented by the following formula (C-2), which is obtained by reacting a compound represented by the formula (C-2) with the following formula (C-3) a step of the compound of the formula (C-4), a step of reducing a nitro group of the compound of the formula (C-4), and a step of reducing a ketone moiety of the β-ketoester structure; CIOC-X ₁ -X ₂ -X ₆ -X ₇ -X ₈ (C-1) (In the formulae (DIA), (C-1), (C-2), (C-3), and (C-4), X ₁ represents a monocyclic ring having 5 or 6 atoms, and the number of atoms is 5 or An unsubstituted or substituted carbocyclic ring selected from a group of 6 adjacent monocyclic rings, a ring system of 8 to 10 atoms, and a ring system of 13 or 14 ring atoms. a heterocyclic aromatic group; X ₂ represents a single bond or at least one divalent bond group selected from the group consisting of ethers, esters, guanamines, and urethanes; X ₆ represents a single bond Or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; X ₇ represents a single bond or a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms; and X ₈ represents a carbon number of 1~ a linear alkyl group of 20; X ₉ represents a single bond, a methylene group or a C 2 to 6 alkyl group, but the alkyl group may be substituted with a hydroxyl group; X ₁₀ represents a single bond, an oxygen atom, *- OCO-, *-OCH ₂ -, *-COO-, *-NHCO- or *-CONH- (only, the key bond with "*" is bonded to X ₉ ), but when X ₉ is a single bond , X ₁₀ is a single button).