JP6330662B2 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Description

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

The liquid crystal display element is known as a light, thin and low power consumption display device, and has been remarkably developed in recent years.
The liquid crystal display element is configured by sandwiching and enclosing a liquid crystal layer between a pair of substrates, and orienting liquid crystals in the liquid crystal layer in a predetermined direction between the substrates. In a liquid crystal display element, a liquid crystal responds by applying a voltage to electrodes provided on a pair of substrates, and a desired image can be displayed using an orientation change due to the response of the liquid crystal.

  In the liquid crystal display element, the alignment of the liquid crystal in the liquid crystal layer is realized by providing a liquid crystal alignment film having an ability to control the alignment of the liquid crystal on a pair of substrate surfaces sandwiching the liquid crystal display element. In other words, the liquid crystal alignment film is formed on the outermost surface of the liquid crystal display element in contact with the liquid crystal of the pair of substrates, and has a function of aligning the liquid crystal between the substrates in a predetermined direction such as a direction parallel to the substrates. It is a member.

Furthermore, in addition to the function of aligning the liquid crystal in a predetermined direction, the liquid crystal alignment film is required to have a function of controlling the pretilt angle of the liquid crystal so that the liquid crystal is aligned with a pretilt angle formed with the substrate. There is.
On the other hand, the ability to control the alignment of liquid crystal in the liquid crystal alignment film (hereinafter referred to as alignment control ability) can be imparted by performing an alignment treatment on the organic film constituting the liquid crystal alignment film.

  A rubbing method has been conventionally known as an alignment treatment for a liquid crystal alignment film that imparts alignment control ability. The rubbing method is a method of rubbing (rubbing) the surface of an organic film such as polyvinyl alcohol, polyamide or polyimide on a substrate with a cloth such as cotton, nylon or polyester in the rubbing direction (rubbing direction). This is a method of aligning liquid crystals. Since this rubbing method can easily realize a relatively stable alignment state of liquid crystals, it has been used in the manufacturing process of conventional liquid crystal display elements. As an organic film used for the liquid crystal alignment film, a polyimide organic film having excellent reliability such as heat resistance and electrical characteristics has been selected and used.

However, in the rubbing method of rubbing the surface of the liquid crystal alignment film, which is an organic film, generation of dust and static electricity sometimes becomes a problem. In addition, due to the high definition of the liquid crystal surface element in recent years and the unevenness caused by the corresponding electrodes on the substrate and the switching active element for driving the liquid crystal, the surface of the liquid crystal alignment film cannot be uniformly rubbed with a cloth. In some cases, alignment of the liquid crystal could not be realized.
Therefore, a photo-alignment method has been actively studied as another alignment treatment method for a liquid crystal alignment film that is not rubbed.

There are various photo alignment methods. Anisotropy is formed in the organic film constituting the liquid crystal alignment film by linearly polarized light or collimated light, and the liquid crystal is aligned according to the anisotropy.
A decomposition type photo-alignment method is known as a main photo-alignment method. For example, by irradiating a polyimide film with polarized ultraviolet light, utilizing the dependency of the molecular structure on the polarization direction of the absorption of ultraviolet light, causing anisotropic decomposition and aligning the liquid crystal with the remaining polyimide without decomposition. Yes (see, for example, Patent Document 1).

  In addition, photocrosslinking type and photoisomerization type photo-alignment methods are also known. For example, using polyvinyl cinnamate, irradiating polarized ultraviolet light, causing a dimerization reaction (crosslinking reaction) at the double bond portion of two side chains parallel to the polarized light, and aligning the liquid crystal in a direction perpendicular to the polarization direction This is a method (for example, see Non-Patent Document 1).

  As in the above example, the liquid crystal alignment film alignment treatment method by the photo alignment method eliminates the need for rubbing, and there is no fear of generation of dust or static electricity. Furthermore, an alignment process can be performed on a substrate of a liquid crystal display element having a concavo-convex surface, which is a method for aligning a liquid crystal alignment film suitable for an industrial production process.

However, a problem peculiar to using light is pointed out also in the photo-alignment method.
In other words, when the organic film on the substrate on which the electrode or the like is formed is irradiated with linearly polarized light or collimated light, the alignment process may be disturbed due to the influence of light reflection from the lower substrate or the like. Such disturbance of the alignment treatment deteriorates the display quality of the obtained liquid crystal display element.

  In addition, unreacted groups may remain in the liquid crystal alignment film even after irradiation with light. When a liquid crystal display element is manufactured using such a liquid crystal alignment film, the light having a short wavelength in backlight or external light is used. Therefore, there is a problem that a defect such that an unreacted group reacts and the alignment state of the liquid crystal changes occurs.

  For example, in Patent Document 2, for example, a short wavelength component in reflected light or backlight light from a substrate or the like is provided on the lower layer side of the liquid crystal alignment film by the photo-alignment method. A technique for further providing a resin layer for attenuating the vibration is disclosed.

Japanese Patent No. 3893659 Specification Japanese Patent No. 4656177

M.M. Shadt et al. , Jpn. J. et al. Appl. Phys. 31, 2155 (1992)

However, providing a further resin layer below the liquid crystal alignment film increases the manufacturing process of the liquid crystal display element as compared with the conventional case. That is, there is a concern that the manufacturing method of the liquid crystal display element using the photo-alignment method is complicated as compared with the conventional method and the productivity is lowered.
Therefore, in the manufacture of a liquid crystal display element using a photo-alignment method, it is possible to provide a liquid crystal display element free from alignment disturbance due to light reflection according to the same manufacturing method as before without complicating the manufacturing process. Technology is required.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a liquid crystal aligning agent capable of manufacturing a liquid crystal display element with reduced alignment disorder, and the liquid crystal, regardless of a complicated manufacturing method. Another object is to provide a liquid crystal alignment film formed from an alignment agent, and further a liquid crystal display element having the liquid crystal alignment film.

The present invention has the following gist.
1. a first polymer that reacts with light in the wavelength range of 250-380 nm;
A liquid crystal aligning agent containing a compound having an absorption maximum in a wavelength range of 250 to 380 nm and at least one of a second polymer.

2. 2. The liquid crystal aligning agent according to 1 above, wherein the content of at least one of the compound and the second polymer is 3 to 80% by mass of the total content combined with the first polymer.
3. The first polymer has a photoreactive group that reacts with light, and the photoreactive group is at least one structure selected from the group consisting of a cinnamoyl structure, a coumarin structure, and a chalcone structure. 3. The liquid crystal aligning agent according to 1 or 2 above.

（破線は重合体の主鎖への結合基を表す。
Ｒは、水素原子、炭素原子数１〜１０のアルキル基（ただし、その任意の水素原子はフッ素原子に置き換わっていてもよい。）、又は炭素原子数１〜１０アルコキシル基（ただし、その任意の水素原子はフッ素原子に置き換わっていてもよい。）を表す。
Ａ及びＢは、それぞれ独立に、単結合又は下記式に示す環構造を表す。4). The liquid crystal aligning agent of said 3 with which the said photoreactive group contains either of the following side chain structures.

(The broken line represents a bonding group to the main chain of the polymer.
R is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (however, any hydrogen atom may be replaced by a fluorine atom), or an alkoxyl group having 1 to 10 carbon atoms (however, any of them) A hydrogen atom may be replaced by a fluorine atom).
A and B each independently represent a single bond or a ring structure represented by the following formula.

Ｔは、それぞれ独立に、単結合、エーテル、エステル、アミド又はケトン結合を表す。Ｓは、単結合又は炭素原子数１〜１０のアルキレン基を表す。
ただし、ＳとＡが共に単結合の場合、酸素原子は隣り合うことはない。）

Each T independently represents a single bond, an ether, an ester, an amide or a ketone bond. S represents a single bond or an alkylene group having 1 to 10 carbon atoms.
However, when S and A are both single bonds, oxygen atoms are not adjacent to each other. )

（Ｒは、炭素原子数１〜５のアルキル基を表す。）5. The liquid crystal aligning agent according to any one of the above 1 to 4, wherein the compound and the second polymer have a specific structure, and the specific structure is at least one of a phenone structure and a diphenylamine structure.
6). 6. The liquid crystal aligning agent according to 5 above, wherein the specific structure is a structure represented by the following formula.

(R represents an alkyl group having 1 to 5 carbon atoms.)

7). 7. The liquid crystal aligning agent according to any one of 1 to 6, wherein the first polymer is at least one polymer selected from the group consisting of polyamic acid and polyimide obtained by imidizing the polyamic acid.
8). 1 to 7, wherein the second polymer is contained, and the second polymer is at least one polymer selected from the group consisting of a polyamic acid and a polyimide obtained by imidizing the polyamic acid. The liquid crystal aligning agent in any one.

9. A liquid crystal alignment film obtained by applying the liquid crystal aligning agent according to any one of the above 1 to 8, drying, and baking.
10. 10. The liquid crystal alignment film according to 9 above, wherein the firing temperature is 50 to 300 ° C.
11. 11. The liquid crystal alignment film according to 9 or 10 above, wherein the film thickness after firing is 5 to 300 nm.
12 A liquid crystal display element comprising the liquid crystal alignment film according to any one of 9 to 11 above.

  By using the liquid crystal aligning agent of the present invention, a liquid crystal alignment film that can be used for manufacturing a liquid crystal display element with reduced alignment disorder is formed regardless of a complicated manufacturing method, and the liquid crystal having the liquid crystal alignment film The display element is used as an element for a portable information terminal that displays a high-definition image as a lightweight, thin, and low power consumption display device.

It is a graph which shows the relationship between the film thickness of the orientation film of a liquid crystal cell, and a pretilt angle.

The present inventor found that during the photo-alignment treatment of the liquid crystal alignment film, light interference occurs in the liquid crystal alignment film due to light reflection from the lower layer such as a glass substrate or an electrode, and the photo-alignment of the liquid crystal alignment film. It was confirmed that the interference caused by the reflected light in the treatment affects the ability to control the alignment of the liquid crystal alignment film, in particular, the ability to form the pretilt angle. Specifically, in the liquid crystal display element, it was confirmed that the film thickness dependency of the liquid crystal alignment film was dependent on the pretilt angle of the liquid crystal.
The dependency of the pretilt angle of the liquid crystal on the film thickness of the liquid crystal alignment film causes variations in the pretilt angle within the plane of one liquid crystal display element to be manufactured and between a plurality of liquid crystal display elements, and thus the display It has been found that this causes a decline in quality.

For example, as disclosed in Patent Document 2 described above, the interference of light that is concerned about the liquid crystal alignment film during the photo alignment process is reflected light between the layer that reflects light in the lower layer of the liquid crystal alignment film. An effective method is to provide a layer that absorbs water separately.
However, providing a new layer for absorbing light increases the manufacturing process of the liquid crystal display element as described above and makes it complicated. That is, if the liquid crystal alignment film itself can be provided with a function capable of reducing the influence of reflected light without providing a new layer for absorbing light, it is an effective method for reducing light interference.

The present inventor conducted further research and included in the liquid crystal alignment film a material capable of attenuating the reflected light during the photo-alignment treatment, in particular, attenuates the reflected light in the lower layer portion inside the liquid crystal alignment film. It has been found that forming a layer is effective in suppressing light interference.
In addition, the layer that suppresses the interference of light in the liquid crystal alignment film is usually a polymer. When the liquid crystal alignment film, which is a polymer, is formed, the phenomenon of polymer layer separation is used to prevent the light interference in the liquid crystal alignment film. It has been found that formation of a layer that suppresses the occurrence is possible. As a result, the present invention has been completed.

That is, when forming a liquid crystal alignment film that is a polymer, layer separation is caused using a plurality of components, and a layer of a component suitable for photo-alignment is formed mainly in the upper layer portion of the formed liquid crystal alignment film, A layer of components effective for light absorption is formed in the lower layer portion.
The obtained liquid crystal alignment film is subjected to a photo-alignment treatment mainly using the upper layer portion, thereby effectively providing liquid crystal alignment. On the other hand, in the lower layer portion of the liquid crystal alignment film, for example, the reflected light from the substrate or the electrode is absorbed and attenuated, and the influence of the reflected light is prevented from reaching the upper layer. As a result, in the liquid crystal alignment film of the present invention, interference of light due to reflected light during the photo-alignment process is suppressed, a desirable photo-alignment process is realized, and the dependency on the alignment film thickness in forming the pretilt angle of the liquid crystal is reduced. Can do.

  In addition, the liquid crystal alignment film of the present invention can be used in backlight light or external light after manufacturing the liquid crystal display element even if unreacted photoreactive groups may remain in the film after the photo-alignment treatment. Generation | occurrence | production of the defect that they react with the light of short wavelength, and the orientation state of a liquid crystal changes can be reduced.

As described above, the liquid crystal alignment film of the present invention utilizes layer separation when forming the alignment film. That is, without applying a special method, a liquid crystal alignment film having a desired structure can be formed in the same liquid crystal alignment film forming process as in the prior art.
As disclosed in Patent Document 2, the liquid crystal alignment film of the present invention does not require a separate step of forming a layer for attenuating reflected light, and a liquid crystal display having a liquid crystal alignment film by a photo alignment method. The manufacturing method of the element is not complicated.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention is at least one of a first polymer that reacts with light in a wavelength range of 250 to 380 nm, a compound having an absorption maximum in a wavelength range of 250 to 380 nm, and a second polymer. , And.
By using the first polymer as a component, an effective photo-alignment treatment can be performed in the liquid crystal alignment film to be formed.

Further, by using a compound having an absorption maximum in the wavelength range of 250 to 380 nm and / or the second polymer as components, light from the lower layer side, for example, reflection from the substrate or the like in the liquid crystal alignment film to be formed. Light can be absorbed and attenuated, and the influence of reflected light or the like can be reduced in the optical alignment treatment.
The content of the compound having the absorption maximum in the wavelength range of 250 to 380 nm and / or the second polymer contained in the liquid crystal aligning agent of the present invention is based on the total amount combined with the first polymer. It is preferable to set it as 3-80 mass%, and 50-80 mass% is more preferable.

[First polymer that reacts with light in the wavelength range of 250 to 380 nm]
The first polymer has at least one structure selected from the group consisting of a cinnamoyl structure, a coumarin structure, and a chalcone structure, which is a reactive group for light having a wavelength range of 250 to 380 nm, preferably 280 to 360 nm. It is preferable to contain a group. Specifically, the photoreactive group of the first polymer preferably contains any of the following side chain structures.

In the above formula, the broken line represents a bonding group to the main chain of the polymer.
R is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (however, any hydrogen atom may be replaced by a fluorine atom), or an alkoxyl group having 1 to 10 carbon atoms (however, any of them) A hydrogen atom may be replaced by a fluorine atom).
A and B each independently represent a single bond or a ring structure represented by the following formula.

  Each T independently represents a single bond, an ether, an ester, an amide or a ketone bond. S represents a single bond or an alkylene group having 1 to 10 carbon atoms. However, when S and A are both single bonds, oxygen atoms are not adjacent to each other.

The main chain of the first polymer is preferably at least one selected from the group consisting of hydrocarbon, polyimide, polyamic acid, acrylate, methacrylate, maleimide, α-methylene-γ-butyrolactone and siloxane.
The first polymer is particularly preferably at least one polymer selected from the group consisting of a polyamic acid and a polyimide obtained by imidizing the polyamic acid. By doing so, a highly reliable liquid crystal alignment film excellent in heat resistance and electrical characteristics can be formed.

  The polyamic acid can be usually obtained by a reaction between a diamine compound and tetracarboxylic dianhydride. Hereinafter, the diamine compound 1 and the tetracarboxylic dianhydride 1 suitable for forming a polyamic acid and a polyimide that are preferable as the first polymer will be described.

[Diamine compound 1]
As the diamine compound 1, not only one type but also a plurality of types can be selected and used, and it is preferable to include one or more diamine compounds having a photoreactive group that reacts with light.
The photoreactive group of the diamine compound 1 is preferably a group that reacts with light in the wavelength range of 250 to 380 nm. Examples of the photoreactive group include at least one group selected from the group consisting of a cinnamoyl structure, a coumarin structure, and a chalcone structure.

Specifically, the photoreactive group of the diamine compound preferably includes any of the following side chain structures.

Ｔは、それぞれ独立に、単結合、エーテル、エステル、アミド又はケトン結合を表す。Ｓは、単結合又は炭素原子数１〜１０のアルキレン基を表す。ただし、ＳとＡが共に単結合の場合、酸素原子は隣り合うことはない。In the above formula, R is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (however, any hydrogen atom may be replaced by a fluorine atom) or an alkoxyl group having 1 to 10 carbon atoms (provided that And any hydrogen atom thereof may be replaced by a fluorine atom).
A and B each independently represent a single bond or a ring structure represented by the following formula.

Each T independently represents a single bond, an ether, an ester, an amide or a ketone bond. S represents a single bond or an alkylene group having 1 to 10 carbon atoms. However, when S and A are both single bonds, oxygen atoms are not adjacent to each other.

Below, the preferable example of the diamine compound which has a photoreactive group is shown.

Note that in _C n _{H 2n + 1} part of the above exemplified diamine compounds with the formula, n represents an integer of 1 to 18.

The liquid crystal alignment film of the present invention can be a vertical alignment liquid crystal alignment film.
As described above, the first polymer used for the formation is preferably at least one polymer selected from the group consisting of polyamic acid and polyimide obtained by imidizing the polyamic acid. Is preferably formed from a diamine component containing a side chain diamine compound.

The above-mentioned side chain type diamine compound is a diamine compound having at least one of an alkyl group, a fluorine-containing alkyl group, an aromatic ring, an aliphatic ring, a heterocyclic ring, and a macrocyclic substituent composed thereof in the side chain. It is.
Specifically, diamine compounds represented by the following formulas [DA-1] to [DA-30] can be exemplified.

（Ｒ_６は、炭素数１〜２２の、アルキル基又はフッ素含有アルキル基である。）

(R ₆ is an alkyl group or a fluorine-containing alkyl group having 1 to 22 carbon atoms.)

（複数あるＳ_５は、それぞれ独立に、−ＣＯＯ−、−ＯＣＯ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−ＣＨ_２−、−Ｏ−、−ＣＯ−、又は−ＮＨ−であり、Ｒ_６は炭素数１〜２２の、アルキル基又はフッ素含有アルキル基である。）

(Several S ₅ are each independently —COO—, —OCO—, —CONH—, —NHCO—, —CH ₂ —, —O—, —CO—, or —NH—, and R ₆ is (It is a C1-C22 alkyl group or a fluorine-containing alkyl group.)

（Ｓ_６は、−Ｏ−、−ＯＣＨ_２−、−ＣＨ_２Ｏ−、−ＣＯＯＣＨ_２−、又は−ＣＨ_２ＯＣＯ−であり、Ｒ_７は炭素数１〜２２の、アルキル基、アルコキシ基、フッ素含有アルキル基又はフッ素含有アルコキシ基である。）

(S ₆ is —O—, —OCH ₂ —, —CH ₂ O—, —COOCH ₂ —, or —CH ₂ OCO—, and R ₇ is an alkyl group, alkoxy group having 1 to 22 carbon atoms, A fluorine-containing alkyl group or a fluorine-containing alkoxy group.)

（Ｓ_７は、−ＣＯＯ−、−ＯＣＯ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−ＣＯＯＣＨ_２−、−ＣＨ_２ＯＣＯ−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、又は−ＣＨ_２−であり、Ｒ_８は炭素数１〜２２の、アルキル基、アルコキシ基、フッ素含有アルキル基又はフッ素含有アルコキシ基である。）

(S ₇ is —COO—, —OCO—, —CONH—, —NHCO—, —COOCH ₂ —, —CH ₂ OCO—, —CH ₂ O—, —OCH ₂ —, or —CH ₂ —. R ₈ is an alkyl group, an alkoxy group, a fluorine-containing alkyl group or a fluorine-containing alkoxy group having 1 to 22 carbon atoms.)

（Ｓ_８は、−ＣＯＯ−、−ＯＣＯ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−ＣＯＯＣＨ_２−、−ＣＨ_２ＯＣＯ−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＨ_２−、−Ｏ−、又は−ＮＨ−であり、Ｒ_９はフッ素基、シアノ基、トリフルオロメタン基、ニトロ基、アゾ基、ホルミル基、アセチル基、アセトキシ基、又は水酸基である。）

(S ₈ is —COO—, —OCO—, —CONH—, —NHCO—, —COOCH ₂ —, —CH ₂ OCO—, —CH ₂ O—, —OCH ₂ —, —CH ₂ —, —O -Or -NH-, and R ₉ is a fluorine group, a cyano group, a trifluoromethane group, a nitro group, an azo group, a formyl group, an acetyl group, an acetoxy group, or a hydroxyl group.

（Ｒ_１０は炭素数３〜１２のアルキル基であり、１，４−シクロへキシレンのシス−トランス異性は、それぞれトランス体である。）

(R ₁₀ is an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomerism of 1,4-cyclohexylene is a trans isomer.)

Simultaneously with the diamine compound having the photoreactive group described above, the diamine compounds of the formulas [DA-1] to [DA-30] can be used in combination for the purpose of supplementing the vertical alignment ability. As a more preferred diamine that can be used in combination, Formulas [DA-10] to [DA-30] are preferable, and Formulas [DA-10] to [DA-16] are more preferable in terms of voltage holding ratio and residual accumulated voltage. It is a diamine compound.
Although preferable content of these diamine compounds is not specifically limited, 5-50 mol% is preferable in the diamine component for forming a 1st polymer, More preferably, it is 5-30 mol%.

  As the above-mentioned first polymer, preferred diamine components suitable for forming polyamic acid and polyimide include the above-mentioned diamine compounds having a photoreactive group, side chain diamine compounds, and other diamine compounds. (It may be referred to as other diamine compounds.). Other diamine compounds are not particularly limited, and examples thereof include alicyclic diamines, aromatic diamines, aromatic-aliphatic diamines, heterocyclic diamines, and aliphatic diamines. Specific examples thereof are as follows.

Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4′-diaminodicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexylamine, isophorone Examples include diamines.
Examples of aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1,4-diamino. 2-methoxybenzene, 2,5-diamino-p-xylene, 1,3-diamino-4-chlorobenzene, 3,5-diaminobenzoic acid, 1,4-diamino-2,5-dichlorobenzene, 4,4 '-Diamino-1,2-diphenylethane, 4,4'-diamino-2,2'-dimethylbibenzyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane 4,4′-diamino-3,3′-dimethyldiphenylmethane, 2,2′-diaminostilbene, 4,4′-diaminostilbene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,5-bis (4-aminophenoxy) ) Benzoic acid, 4,4′-bis (4-aminophenoxy) bibenzyl, 2,2-bis [(4-aminophenoxy) methyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] Hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (3-aminophenyl) Enoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 1,1-bis (4-aminophenyl) cyclohexane, α, α′-bis (4-aminophenyl) -1,4- Diisopropylbenzene, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 ′ -Diaminodiphenylamine, 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrene, 1,6-diaminopyrene, 1,8- Diaminopyrene, 2,7-diaminofluorene, 1,3-bis (4-aminophenyl) tetramethyldisi Xanthine, benzidine, 2,2′-dimethylbenzidine, 1,2-bis (4-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,4-bis (4-aminophenyl) butane 1,5-bis (4-aminophenyl) pentane, 1,6-bis (4-aminophenyl) hexane, 1,7-bis (4-aminophenyl) heptane, 1,8-bis (4-aminophenyl) ) Octane, 1,9-bis (4-aminophenyl) nonane, 1,10-bis (4-aminophenyl) decane, 1,3-bis (4-aminophenoxy) propane, 1,4-bis (4- Aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,7-bis (4-aminophenoxy) heptane 1,8-bis (4-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,10-bis (4-aminophenoxy) decane, di (4-aminophenyl) propane-1, 3-dioate, di (4-aminophenyl) butane-1,4-dioate, di (4-aminophenyl) pentane-1,5-dioate, di (4-aminophenyl) hexane-1,6-dioate, di (4-aminophenyl) heptane-1,7-dioate, di (4-aminophenyl) octane-1,8-dioate, di (4-aminophenyl) nonane-1,9-dioate, di (4-aminophenyl) ) Decane-1,10-dioate, 1,3-bis [4- (4-aminophenoxy) phenoxy] propane, 1,4-bis [4- (4-aminopheno) Phenoxy] butane, 1,5-bis [4- (4-aminophenoxy) phenoxy] pentane, 1,6-bis [4- (4-aminophenoxy) phenoxy] hexane, 1,7-bis [4- (4-aminophenoxy) phenoxy] heptane, 1,8-bis [4- (4-aminophenoxy) phenoxy] octane, 1,9-bis [4- (4-aminophenoxy) phenoxy] nonane, 1,10- And bis [4- (4-aminophenoxy) phenoxy] decane.

  Examples of aromatic-aliphatic diamines include 3-aminobenzylamine, 4-aminobenzylamine, 3-amino-N-methylbenzylamine, 4-amino-N-methylbenzylamine, 3-aminophenethylamine, 4 -Aminophenethylamine, 3-amino-N-methylphenethylamine, 4-amino-N-methylphenethylamine, 3- (3-aminopropyl) aniline, 4- (3-aminopropyl) aniline, 3- (3-methylaminopropyl) ) Aniline, 4- (3-methylaminopropyl) aniline, 3- (4-aminobutyl) aniline, 4- (4-aminobutyl) aniline, 3- (4-methylaminobutyl) aniline, 4- (4- Methylaminobutyl) aniline, 3- (5-aminopentyl) aniline, 4- (5-aminopentyl) Aniline, 3- (5-methylaminopentyl) aniline, 4- (5-methylaminopentyl) aniline, 2- (6-aminonaphthyl) methylamine, 3- (6-aminonaphthyl) methylamine, 2- (6 -Aminonaphthyl) ethylamine, 3- (6-aminonaphthyl) ethylamine and the like.

  Examples of heterocyclic diamines include 2,6-diaminopyridine, 2,4-diaminopyridine, 2,4-diamino-1,3,5-triazine, 2,7-diaminodibenzofuran, 3,6-diamino. Examples thereof include carbazole, 2,4-diamino-6-isopropyl-1,3,5-triazine, 2,5-bis (4-aminophenyl) -1,3,4-oxadiazole.

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

[Tetracarboxylic dianhydride 1]
The tetracarboxylic dianhydride to be reacted with the above-described diamine compound for obtaining a polyamic acid preferable as the first polymer is not particularly limited. Specific examples are given below.

Examples of the tetracarboxylic dianhydride having an alicyclic structure or an aliphatic structure include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutane. Tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetra Carboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic Acid dianhydride, 3,4-dicarboxy-1-cyclohexyl succinic dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, 1, , 3,4-Butanetetracarboxylic dianhydride, bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetra Carboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride , Tricyclo [4.2.1.0 ^2,5 ] nonane-3,4,7,8-tetracarboxylic acid-3,4: 7,8-dianhydride, hexacyclo [6.6.0.1 ^{2 , 7} . 0 ^3,6 . 1 ^9,14 . 0 ^10,13] hexadecane -4,5,11,12- tetracarboxylic acid-4,5: 11,12-dianhydride, 4- (2,5-di-oxo-tetrahydrofuran-3-yl) -1,2 3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride and the like.

  As aromatic tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic acid Dianhydride, 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,3,3 ′, 4-benzophenonetetra Carboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride Products, 2,3,6,7-naphthalenetetracarboxylic dianhydride and the like.

When aromatic tetracarboxylic dianhydride is used in addition to the above-mentioned tetracarboxylic dianhydride having an alicyclic structure or aliphatic structure, the liquid crystal alignment is improved and the accumulated charge of the liquid crystal cell is reduced. This is preferable.
Tetracarboxylic dianhydride can be used alone or in combination of two or more depending on the liquid crystal alignment properties of the liquid crystal alignment film to be formed, such as voltage holding characteristics and accumulated charges.

[Polyamic acid 1]
A polyamic acid preferable as the first polymer can be obtained by a reaction between the tetracarboxylic dianhydride described above and a diamine component composed of the diamine compound described above.
As a method for obtaining the polyamic acid as the first polymer, a known synthesis method can be used. In general, tetracarboxylic dianhydride and a diamine component are reacted in an organic solvent.
The reaction between the tetracarboxylic dianhydride and the diamine compound is advantageous in that it proceeds relatively easily in an organic solvent and no by-product is generated.

  The organic solvent used for the reaction between the tetracarboxylic dianhydride and the diamine compound is not particularly limited as long as the generated polyamic acid can be dissolved. Specific examples are given below.

  N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide , Γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl Carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethyl 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 monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene Glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n- Hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, Ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropion , 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy -N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide and the like can be mentioned.

These organic solvents may be used alone or in combination. Further, even a solvent that does not dissolve the polyamic acid may be used by mixing with the above-mentioned organic solvent as long as the generated polyamic acid does not precipitate.
Since water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the produced polyamic acid, it is preferable to use a dehydrated and dried organic solvent to the extent possible.

  When the tetracarboxylic dianhydride and the diamine component are reacted in an organic solvent, the solution in which the diamine component is dispersed or dissolved in the organic solvent is stirred, and the tetracarboxylic dianhydride is used as it is or in an organic solvent. Dispersed or dissolved addition method, conversely tetracarboxylic dianhydride dispersed or dissolved in organic solvent, diamine component added, tetracarboxylic dianhydride and diamine component added alternately Any of these methods may be used. Further, when the tetracarboxylic dianhydride or diamine component is composed of a plurality of types of compounds, they may be reacted in a premixed state, may be individually reacted sequentially, or may be further reacted individually. May be mixed to form a high molecular weight product.

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

  In the above polymerization reaction, the ratio of the total number of moles of tetracarboxylic dianhydride and the total number of moles of the diamine component is preferably 0.8 to 1.2, more preferably 0.9 to 1.1. preferable. Similar to the normal polycondensation reaction, the molecular weight of the polyamic acid produced increases as the molar ratio approaches 1.0.

[Polyimide 1]
A polyimide preferable as the first polymer can be obtained by dehydrating and ring-closing (imidizing) the polyamic acid described above.
As a preferable polyimide, the dehydration cyclization rate (imidation rate) of the amic acid group is not necessarily 100%, and can be arbitrarily adjusted so as to be 100% or less depending on the application and purpose.

Examples of the method for imidizing the polyamic acid include thermal imidization in which the polyamic acid solution is heated as it is, and catalytic imidization in which a catalyst is added to the polyamic acid solution.
The temperature at which the polyamic acid is thermally imidized in the solution is 100 to 400 ° C., preferably 120 to 250 ° C., and the method is preferably performed while removing water generated by the imidization reaction from the system.

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

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

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

[Polyamic acid ester]
As a 1st polymer used as the component of the liquid crystal aligning agent of this invention, it is also possible to set it as polyamic acid ester and polyamide other than the polyamic acid and polyimide which were mentioned above.

As a method for synthesizing a preferable polyamic acid ester, a method of reacting a tetracarboxylic acid diester dichloride with the above-mentioned preferable diamine compound, or a method of reacting a tetracarboxylic acid diester with the above-mentioned preferable diamine compound in the presence of a condensing agent, a base, or the like. There is. By these methods, a polyamic acid ester which is a kind of polyimide precursor can be obtained.
Alternatively, a polyamic acid ester can be obtained by esterifying a carboxylic acid in an amic acid with a polymerized polyamic acid using a polymer reaction.

  Specifically, tetracarboxylic acid diester dichloride and the above-mentioned preferred diamine compound 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, preferably 1 It can be synthesized by reacting for ~ 4 hours.

  As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferable because the reaction proceeds gently. The addition amount of the base is preferably 2 to 4 moles with respect to the tetracarboxylic acid diester dichloride, from the viewpoint that it can be easily removed and a high molecular weight product is easily obtained. 5 times mole is more preferable.

  When the condensation polymerization reaction is performed in the presence of a condensing agent, examples of the condensing agent include triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, and N, N′-carbonyldioxide. Imidazole, dimethoxy-1,3,5-triazinylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium tetrafluoroborate, O— (Benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate diphenyl, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) 4-methoxymorpholium chloride n- Hydrates can be used.

  In addition, in the method using a condensing agent, when a Lewis acid is added as an additive, the reaction proceeds efficiently. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The addition amount of the Lewis acid is preferably 0.1 to 1.0 mole, more preferably 0.5 to 1.0 mole, relative to the tetracarboxylic acid diester.

  As the organic solvent, the organic solvent used when polymerizing the above-described tetracarboxylic dianhydride and a preferred diamine component to obtain a polyamic acid can be used. From the solubility of the monomer and the resulting polymer, N Use of -methyl-2-pyrrolidone, γ-butyrolactone and the like is preferable. These solvents may be used alone or in combination of two or more. In order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the organic solvent used for the synthesis of the polyamic acid ester is preferably dehydrated as much as possible.

The total concentration of the tetracarboxylic acid diester dichloride and the diamine component in the reaction solution is preferably 1 to 30% by mass, and preferably 5 to 20% by mass from the viewpoint that the polymer is hardly precipitated and a high molecular weight product is easily obtained. Is more preferable.
Furthermore, the reaction is preferably performed in a nitrogen atmosphere to prevent outside air from being mixed.

〔polyamide〕
The polyamide preferable as the first polymer described above can also be synthesized in the same manner as the polyamic acid ester described above.

[Recovery of polymer]
When recovering the produced polyamic acid, polyimide, and the like from a reaction solution such as polyamic acid and polyimide, the reaction solution is poured into a poor solvent to precipitate the polymer. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and water.
The precipitated polymer can be collected by filtration, and then dried at normal temperature or reduced pressure at room temperature or by heating. Moreover, when the polymer which carried out precipitation collection | recovery is re-dissolved in an organic solvent and the operation which carries out reprecipitation collection | recovery is repeated 2 to 10 times, the impurity in a polymer can be decreased. Examples of the poor solvent at this time include alcohols, ketones, hydrocarbons and the like, and it is preferable to use three or more kinds of poor solvents selected from these because purification efficiency is further improved.

  The molecular weight of the polyamic acid and / or polyimide contained as the first polymer is determined based on GPC (Gel Permeation Chromatography) in consideration of the strength of the obtained coating film, workability when forming the coating film, and uniformity of the coating film. ) The weight average molecular weight measured by the method is preferably 2,000 to 1,000,000, more preferably 5,000 to 100,000.

[Compound and second polymer having absorption maximum in wavelength range of 250 to 380 nm]
The compound and the second polymer have at least one selected from the group consisting of a cinnamoyl structure, a phenone structure, and a diphenylamine structure having an absorption maximum with respect to light having a wavelength range of 250 to 380 nm, preferably 280 to 360 nm. It preferably has a specific structure, and more preferably has at least one specific structure of a phenone structure and a diphenylamine structure. In the present invention, having an absorption maximum means having an absorption maximum wavelength in the range of 250 to 380 nm when the UV-vis spectrum of the monomer used in the polymer of the present invention or itself is measured. There is a meaning.
Specific examples of the specific structure are preferably compounds represented by the following.

（Ｒは、炭素原子数１〜５のアルキル基を表す。）

(R represents an alkyl group having 1 to 5 carbon atoms.)

  In particular, the preferred second polymer is preferably at least one polymer selected from the group consisting of a polyamic acid and a polyimide obtained by imidizing the polyamic acid. By doing so, a highly reliable liquid crystal alignment film excellent in heat resistance and electrical characteristics can be formed.

As described above, the polyamic acid can be usually obtained by a reaction between a diamine compound and tetracarboxylic dianhydride.
Hereinafter, the diamine compound and tetracarboxylic dianhydride that can be used for forming a preferable polyamic acid and polyimide as the second polymer will be described.

[Diamine compound 2]
The diamine compound that can be used for forming the preferred polyamic acid and polyimide as the second polymer is not particularly limited, but alicyclic diamines, aromatic diamines, aromatic-aliphatic diamines, and heterocyclic compounds. Examples include diamines and aliphatic diamines. These diamines are selected and used in combination so as to form a polymer having an absorption maximum in a wavelength range of 250 to 380 nm by reaction with tetracarboxylic dianhydride described later. Specific examples of usable diamine compounds are as follows.

  Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4′-diaminodicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexylamine, isophorone Examples include diamines.

  Examples of aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1,4-diamino. 2-methoxybenzene, 2,5-diamino-p-xylene, 1,3-diamino-4-chlorobenzene, 3,5-diaminobenzoic acid, 1,4-diamino-2,5-dichlorobenzene, 4,4 '-Diamino-1,2-diphenylethane, 4,4'-diamino-2,2'-dimethylbibenzyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane 4,4'-diamino-3,3'-dimethyldiphenylmethane, 2,2'-diaminostilbene, 4,4'-diamy Stilbene, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, 4,4′- Diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,5-bis (4- Aminophenoxy) benzoic acid, 4,4′-bis (4-aminophenoxy) bibenzyl, 2,2-bis [(4-aminophenoxy) methyl] propane, 2,2-bis [4- (4-aminophenoxy) Phenyl] hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 1,1-bis (4-aminophenyl) cyclohexane, α, α′-bis (4- Aminophenyl) -1,4-diisopropylbenzene, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) Hexafluoropropane, 4,4'-diaminodiphenylamine, 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrene, 1,6 -Diaminopyrene, 1,8-diaminopyrene, 2,7-diaminofluorene, 1,3-bis (4-amino Enyl) tetramethyldisiloxane, benzidine, 2,2′-dimethylbenzidine, 1,2-bis (4-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,4-bis (4 -Aminophenyl) butane, 1,5-bis (4-aminophenyl) pentane, 1,6-bis (4-aminophenyl) hexane, 1,7-bis (4-aminophenyl) heptane, 1,8-bis (4-aminophenyl) octane, 1,9-bis (4-aminophenyl) nonane, 1,10-bis (4-aminophenyl) decane, 1,3-bis (4-aminophenoxy) propane, 1,4 -Bis (4-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,7-bis (4- Aminophenoxy) heptane, 1,8-bis (4-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,10-bis (4-aminophenoxy) decane, di (4-aminophenyl) ) Propane-1,3-dioate, di (4-aminophenyl) butane-1,4-dioate, di (4-aminophenyl) pentane-1,5-dioate, di (4-aminophenyl) hexane-1, 6-dioate, di (4-aminophenyl) heptane-1,7-dioate, di (4-aminophenyl) octane-1,8-dioate, di (4-aminophenyl) nonane-1,9-dioate, di (4-aminophenyl) decane-1,10-dioate, 1,3-bis [4- (4-aminophenoxy) phenoxy] propane, 1,4-bi [4- (4-aminophenoxy) phenoxy] butane, 1,5-bis [4- (4-aminophenoxy) phenoxy] pentane, 1,6-bis [4- (4-aminophenoxy) phenoxy] hexane, , 7-bis [4- (4-aminophenoxy) phenoxy] heptane, 1,8-bis [4- (4-aminophenoxy) phenoxy] octane, 1,9-bis [4- (4-aminophenoxy) phenoxy Nonane, 1,10-bis [4- (4-aminophenoxy) phenoxy] decane, and the like.

  Examples of aromatic-aliphatic diamines include 3-aminobenzylamine, 4-aminobenzylamine, 3-amino-N-methylbenzylamine, 4-amino-N-methylbenzylamine, 3-aminophenethylamine, 4 -Aminophenethylamine, 3-amino-N-methylphenethylamine, 4-amino-N-methylphenethylamine, 3- (3-aminopropyl) aniline, 4- (3-aminopropyl) aniline, 3- (3-methylaminopropyl) ) Aniline, 4- (3-methylaminopropyl) aniline, 3- (4-aminobutyl) aniline, 4- (4-aminobutyl) aniline, 3- (4-methylaminobutyl) aniline, 4- (4- Methylaminobutyl) aniline, 3- (5-aminopentyl) aniline, 4- (5-aminopentyl) Aniline, 3- (5-methylaminopentyl) aniline, 4- (5-methylaminopentyl) aniline, 2- (6-aminonaphthyl) methylamine, 3- (6-aminonaphthyl) methylamine, 2- (6 -Aminonaphthyl) ethylamine, 3- (6-aminonaphthyl) ethylamine and the like.

  Examples of heterocyclic diamines include 2,6-diaminopyridine, 2,4-diaminopyridine, 2,4-diamino-1,3,5-triazine, 2,7-diaminodibenzofuran, 3,6-diamino. Examples thereof include carbazole, 2,4-diamino-6-isopropyl-1,3,5-triazine, 2,5-bis (4-aminophenyl) -1,3,4-oxadiazole.

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

  Among the diamine compounds described above, 4,4′-diaminodiphenylamine and / or 4,4′-diaminobenzophenone is particularly preferably selected and used to form polyamic acid and polyimide. This is because the polyamic acid and polyimide to be formed can have a higher absorption maximum in the wavelength range of 250 to 380 nm.

[Tetracarboxylic dianhydride 2]
The tetracarboxylic dianhydride that can be used for forming the polyamic acid and polyimide that are preferable as the second polymer is not particularly limited. The combination is selected and used so as to form a polymer having an absorption maximum in the wavelength range of 250 to 380 nm by the reaction with the diamine compound described above. Specific examples of tetracarboxylic dianhydrides that can be used are as follows.

Examples of the tetracarboxylic dianhydride having an alicyclic structure or an aliphatic structure include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutane. Tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetra Carboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic Acid dianhydride, 3,4-dicarboxy-1-cyclohexyl succinic dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, 1, , 3,4-Butanetetracarboxylic dianhydride, bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetra Carboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride , Tricyclo [4.2.1.0 ^2,5 ] nonane-3,4,7,8-tetracarboxylic acid-3,4: 7,8-dianhydride, hexacyclo [6.6.0.1 ^{2 , 7} . 0 ^3,6 . 1 ^9,14 . 0 ^10,13] hexadecane -4,5,11,12- tetracarboxylic acid-4,5: 11,12-dianhydride, 4- (2,5-di-oxo-tetrahydrofuran-3-yl) -1,2 3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride and the like.

  As aromatic tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic acid Dianhydride, 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,3,3 ′, 4-benzophenonetetra Carboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride Products, 2,3,6,7-naphthalenetetracarboxylic dianhydride and the like.

  In addition to the tetracarboxylic dianhydride having the alicyclic structure or aliphatic structure described above, the use of aromatic tetracarboxylic dianhydride improves the liquid crystal alignment of the liquid crystal alignment film formed from the polymer formed. In addition, the accumulated charge in the liquid crystal cell can be reduced, which is preferable.

  Among the tetracarboxylic dianhydrides described above, in particular, pyromellitic dianhydride and / or 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride is selected to form polyamic acid and polyimide. It is preferable to use for. This is because the polyamic acid and polyimide to be formed can have a higher absorption maximum in the wavelength range of 250 to 380 nm.

[Polyamic acid 2 and polyimide 2]
A polyamic acid preferable as the second polymer can be obtained by a reaction between the tetracarboxylic dianhydride described above and a diamine component composed of the diamine compound described above.
As a method for obtaining the polyamic acid as the second polymer, a known synthesis method can be used. For example, the first polymer described above can be obtained by the same method as described as a method for obtaining a preferable polyamic acid.

  Moreover, a polyimide preferable as the second polymer can be obtained by dehydrating and ring-closing (imidizing) the obtained polyamic acid. Specifically, it can be obtained by the same method as described as a method for obtaining a preferable polyimide as the first polymer.

  In the polyimide preferable as the second polymer, the dehydration cyclization rate (imidation rate) of the amic acid group is not necessarily 100%, and is arbitrarily adjusted so as to be 100% or less depending on the application and purpose. can do.

  The molecular weight of the polyamic acid and / or polyimide contained as the second polymer is GPC (Gel Permeation Chromatography) in consideration of the strength of the obtained coating film, workability during coating film formation, and uniformity of the coating film. ) The weight average molecular weight measured by the method is preferably 2,000 to 1,000,000, more preferably 5,000 to 100,000.

  Examples of the compound having an absorption maximum in the wavelength range of 250 to 380 nm, which is another component in the liquid crystal aligning agent of the present invention, include diamine compounds and tetracarboxylic acids that are preferable for the formation of the second polymer described above. It is preferable to use an acid dianhydride. More specifically, examples of the diamine compound include 4,4'-diaminodiphenylamine and 4,4'-diaminobenzophenone. Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride and 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride.

(Preparation of liquid crystal aligning agent)
As described above, the liquid crystal aligning agent of the present invention comprises the first polymer that reacts with light in the wavelength range of 250 to 380 nm, the compound having the absorption maximum in the wavelength range of 250 to 380 nm, and the second polymer. It contains at least one of them. The liquid crystal aligning agent is preferably prepared as a coating solution so as to be suitable for forming a liquid crystal alignment film.
That is, the liquid crystal aligning agent of the present invention is preferably prepared as a solution in which a resin component for forming a resin film is dissolved in an organic solvent. Here, the resin component is a resin component including the first polymer and the second polymer already described.
The content of the resin component is preferably 1 to 20% by mass, more preferably 3 to 15% by mass, and particularly preferably 3 to 10% by mass with respect to the total amount (100% by mass) of the liquid crystal aligning agent.

In the liquid crystal aligning agent, all of the above-mentioned resin components may be the first polymer, or the first polymer and the second polymer, but other polymers are mixed. May be. In that case, content of the other polymer in a resin component is 0.5-15 mass%, Preferably it is 1-10 mass%.
Examples of other polymers include polyamic acid, polyimide, etc., which do not react with light in the wavelength range of 250 to 380 nm, and have no absorption maximum in the wavelength range of 250 to 380 nm. Can be mentioned.

  The organic solvent used for the liquid crystal aligning agent is not particularly limited as long as the organic solvent dissolves the resin component. Specific examples are given below.

  N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethylsulfoxide, tetramethylurea, pyridine, Dimethylsulfone, hexamethylsulfoxide, γ-butyrolactone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide, 1,3 -Dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, 4-hydroxy-4 Methyl-2-pentanone and the like. These may be used alone or in combination.

  The liquid crystal aligning agent of this invention may contain components other than above-described components, such as a 1st polymer. Examples thereof include solvents and compounds that improve the film thickness uniformity and surface smoothness when a liquid crystal aligning agent is applied, and compounds that improve the adhesion between the liquid crystal aligning film and the substrate.

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

  For example, isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoacetate Isopropyl 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, dipro Lenglycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3 -Methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl Ether, 1-hexanol, n-hexane, n-pentane, n-octane Diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, Ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1 -Butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol- Low 1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl ester, lactate isoamyl ester Examples include solvents having surface tension.

These poor solvents may be used alone or in combination.
When using a poor solvent, it is preferable that it is 5-80 mass% of the whole solvent, More preferably, it is 20-60 mass% so that the solubility of the whole solvent contained in a liquid crystal aligning agent may not be reduced significantly. It is.

  Examples of compounds that improve film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants.

  Specifically, for example, Ftop (registered trademark) 301, EF303, EF352 (above, manufactured by Tochem Products), MegaFac (registered trademark) F171, F173, R-30 (above, manufactured by DIC), Florard FC430, FC431 (above, manufactured by Sumitomo 3M), Asahi Guard (registered trademark) AG710 (made by Asahi Glass Co., Ltd.), Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106 (above, AGC Seimi) Chemical Co., Ltd.). The use ratio of these surfactants is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the resin component contained in the liquid crystal aligning agent.

  Specific examples of the compound that improves the adhesion between the liquid crystal alignment film and the substrate include the following functional silane-containing compounds and epoxy group-containing compounds.

  For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-to Ethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltri Methoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-amino Propyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether , Polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetra Glycidyl-2,4-hexanediol, N, N, N ′, N ′,-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N Examples include ', N',-tetraglycidyl-4,4'-diaminodiphenylmethane.

  Furthermore, in addition to improving the adhesion between the substrate and the liquid crystal alignment film, the following phenoplast type additives are added to the liquid crystal alignment for the purpose of preventing the deterioration of electrical characteristics due to the backlight when the liquid crystal display element is constructed. You may make it contain in an agent. Specific phenoplast additives are shown below, but are not limited to this structure.

  When using the compound which improves adhesiveness with a board | substrate, it is preferable that the usage-amount is 0.1-30 mass parts with respect to 100 mass parts of the resin component contained in a liquid crystal aligning agent, More preferably. Is 1-20 parts by mass. If the amount used is less than 0.1 parts by mass, the effect of improving the adhesion cannot be expected, and if it exceeds 30 parts by mass, the orientation of the liquid crystal may deteriorate.

  In the liquid crystal aligning agent of the present invention, in addition to those described above, a dielectric or conductive material may be used for the purpose of changing electrical characteristics such as dielectric constant and conductivity of the liquid crystal aligning film as long as the effects of the present invention are not impaired. A crosslinkable compound may be added for the purpose of increasing the hardness and density of the substance and, further, the liquid crystal alignment film.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal aligning agent of the present invention is applied onto a substrate and fired in the same manner as a liquid crystal aligning agent for forming a liquid crystal aligning film made of a conventional polyimide, without applying another method separately, The liquid crystal alignment film of the present invention can be formed. Furthermore, by performing photo-alignment treatment by light irradiation, alignment control ability can be imparted and used for manufacturing a liquid crystal display element.

  As a substrate used when a liquid crystal alignment film is formed by applying a liquid crystal aligning agent, it is preferable to use a highly transparent substrate when the manufactured liquid crystal display element is a transmission type. In that case, there is no particular limitation, and a glass substrate or a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used. In order to drive the liquid crystal in the liquid crystal display element, it is preferable to use a substrate on which a transparent electrode such as an ITO (Indium Tin Oxide) electrode is formed from the viewpoint of simplifying the manufacturing process. In the reflective liquid crystal display element, an opaque object such as a silicon wafer can be used as long as it is only on one substrate, and the electrode in this case can be made of a material that reflects light such as aluminum.

  In the formation of the liquid crystal alignment film of the present invention, the application method of the liquid crystal alignment agent is not particularly limited. As the application method of the liquid crystal aligning agent, industrially, screen printing, offset printing, flexographic printing, ink jet, and the like are common. As other coating methods, there are methods using a dip, a roll coater, a slit coater, a spinner and the like, and these may be used according to the purpose.

Firing after applying the liquid crystal aligning agent on the substrate is performed at 50 to 300 ° C., preferably 80 to 250 ° C. for 1 to 200 minutes, preferably 10 to 100 minutes by a heating means such as a hot plate. The solvent, which is the solvent, can be evaporated to form a coating film.
When the thickness of the coating film formed after baking is too thick, it is disadvantageous in terms of power consumption when used for a liquid crystal display element, and when it is too thin, the reliability of the liquid crystal display element may be lowered. Therefore, the thickness of the coating film after baking is preferably 5 to 300 nm, more preferably 10 to 100 nm.

When the liquid crystal is horizontally aligned or tilted, the fired coating film is treated with polarized ultraviolet rays. That is, photo-alignment processing is performed by light irradiation.
Note that the liquid crystal alignment film of the present invention can be imparted with alignment control ability, in particular, a pretilt angle can be formed by rubbing treatment.

  In the liquid crystal display element of the present invention, after obtaining the substrate with the liquid crystal alignment film on which the liquid crystal alignment film is formed from the liquid crystal aligning agent of the present invention by the above-described method, It is an element. For example, a vertical alignment (VA) mode liquid crystal display element can be provided.

To give an example of liquid crystal cell preparation, a pair of substrates on which the liquid crystal alignment film of the present invention is formed is prepared, spacers are scattered on the liquid crystal alignment film of one substrate, and the liquid crystal alignment film surface is on the inside. Then, the other substrate is bonded, the liquid crystal is injected under reduced pressure and sealed, or the liquid crystal is dropped on the liquid crystal alignment film surface on which the spacers are dispersed, and then the substrate is bonded and sealed, Etc. can be illustrated. The diameter of the spacer at this time is preferably 1 to 30 μm, more preferably 2 to 10 μm. This spacer diameter determines the distance between the pair of substrates that sandwich the liquid crystal layer, that is, the thickness of the liquid crystal layer.
As described above, the liquid crystal display device manufactured using the liquid crystal aligning agent of the present invention has excellent reliability and can be suitably used for a large-screen, high-definition liquid crystal television.

The present invention will be described in more detail with reference to the following examples, but the present invention should not be construed as being limited thereto.
Abbreviations and structures of main compounds used in Examples and Comparative Examples are as follows.

(Tetracarboxylic dianhydride)
CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride PMDA: pyromellitic anhydride BODA: bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride

(Diamine)
m-PDA: m-phenylenediamine PCH: 1,3-diamino-4- [4- (4-heptylcyclohexyl) phenoxy] benzene DAM-1: (E) -2,4-diaminophenethyl 3- (4- ( 4-heptylcyclohexyl) phenyl) acrylate

ＤＡＭ−３：Ｎ１−（４−アミノフェニル)−Ｎ１−メチルベンゼン−１，４−ジアミン

DAM-2: N1- (4-aminophenyl) benzene-1,4-diamine

DAM-3: N1- (4-aminophenyl) -N1-methylbenzene-1,4-diamine

ＤＡＭ−５：４，４’−オキシジアニリン

DAM-4: 4,4′-diaminobenzophenone

DAM-5: 4,4'-oxydianiline

DAM-6: 3,5-diaminobenzoic acid

DAM-7: 2,4-diaminophenethylcinnamate

(Organic solvent)
NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve

[Molecular weight measurement]
The molecular weight of the polyimide in the synthesis example was measured as follows using a room temperature gel permeation chromatography (GPC) apparatus (SSC-7200) manufactured by Senshu Science Co., Ltd. and a column (KD-803, KD-805) manufactured by Shodex.
Column temperature: 50 ° C
Eluent: N, N′-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H 2 O) is 30 mmol / L (liter), phosphoric acid / anhydrous crystal (o-phosphoric acid) is 30 mmol / L , Tetrahydrofuran (THF) at 10 ml / L)
Flow rate: 1.0 ml / min Standard sample for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: about 9000000, 150,000, 100,000, and 30000) manufactured by Tosoh Corporation, and polyethylene glycol (molecular weight: about 12000, 4000, and polymer laboratory) 1000).

<Synthesis Example 1>
CBDA (2.499 g, 12.74 mmol) and DAM-1 (6.015 g, 13.0 mmol) were mixed in NMP (48.24 g) and reacted at room temperature for 20 hours to obtain a polyamic acid solution. NMP (42.57 g) and BC (42.57 g) were added to this polyamic acid solution, diluted to 6% by mass, and stirred at room temperature for 5 hours to obtain a polyamic acid solution (A1). The polyamic acid contained had a number average molecular weight of 9000 and a weight average molecular weight of 28,000. The obtained polyamic acid solution (A1) can form a vertically aligned liquid crystal alignment film and can be used as a liquid crystal aligning agent. In Comparative Example 1 described later, a liquid crystal aligning agent is used. Used as (A1).

<Synthesis Example 2>
BODA (1.626 g, 6.24 mmol) and DAM-1 (6.015 g, 13.0 mmol) were mixed in NMP (37.68 g), reacted at 80 ° C. for 5 hours, and then CBDA (1. 224 g, 6.24 mmol) and NMP (12.56 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution. After adding NMP to this polyamic acid solution (58.0 g) and diluting to 6% by mass, acetic anhydride (3.91 g) and pyridine (2.02 g) were added as an imidization catalyst and reacted at 50 ° C. for 3 hours. It was. This reaction solution was poured into methanol (530 ml), and the resulting precipitate was separated by filtration. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (B). The imidation ratio of this polyimide was 50%, the number average molecular weight was 11000, and the weight average molecular weight was 31000.

  NMP (29.3 g) was added to the obtained polyimide powder (B) (6.0 g), and the mixture was dissolved by stirring at 70 ° C. for 5 hours. NMP (34.7g) and BC (30.0g) were added to this solution, and the polyimide solution (B1) was obtained by stirring. The obtained polyimide solution (B1) can form a vertically aligned liquid crystal alignment film and can be used as a liquid crystal aligning agent. In Comparative Example 2 described later, a liquid crystal aligning agent ( Used as B1).

<Synthesis Example 3>
CBDA (2.447 g, 12.48 mmol) and DAM-2 (2.59 g, 13.0 mmol) were mixed in NMP (28.55 g) and reacted at room temperature for 20 hours to obtain a polyamic acid solution. NMP (25.19g) and BC (25.19g) were added to this polyamic acid solution, diluted to 6% by mass, and stirred at room temperature for 5 hours to obtain a polyamic acid solution (C1). The polyamic acid contained had a number average molecular weight of 8,700 and a weight average molecular weight of 18,000.

Next, the polyamic acid solution (A1) (2.0 g) obtained in Synthesis Example 1 and the polyamic acid solution (C1) (8.0 g) were mixed at room temperature for 3 hours to obtain a vertically aligned liquid crystal alignment. A liquid crystal aligning agent (C2) capable of forming a film was prepared.
Further, the polyimide solution (B1) (2.0 g) obtained in Synthesis Example 2 and the polyamic acid solution (C1) (8.0 g) were mixed at room temperature for 3 hours to obtain a vertically aligned liquid crystal alignment film. A liquid crystal aligning agent (C3) capable of forming was prepared.

<Synthesis Example 4>
CBDA (2.447 g, 12.48 mmol) and DAM-3 (2.773 g, 13.0 mmol) were mixed in NMP (29.58 g) and reacted at room temperature for 20 hours to obtain a polyamic acid solution. NMP (26.1 g) and BC (26.1 g) were added to this polyamic acid solution, diluted to 6% by mass, and stirred at room temperature for 5 hours to obtain a polyamic acid solution (D1). The polyamic acid contained had a number average molecular weight of 9100 and a weight average molecular weight of 19000.
Next, the polyamic acid solution (A1) (2.0 g) obtained in Synthesis Example 1 and the polyamic acid solution (D1) (8.0 g) were mixed at room temperature for 3 hours to obtain a vertically aligned liquid crystal alignment film. The liquid crystal aligning agent (D2) which can form is prepared.

<Synthesis Example 5>
CBDA (2.447 g, 12.48 mmol) and DAM-4 (2.759 g, 13.0 mmol) were mixed in NMP (29.5 g) and reacted at room temperature for 20 hours to obtain a polyamic acid solution. NMP (26.0 g) and BC (26.0 g) were added to this polyamic acid solution, diluted to 6% by mass, and stirred at room temperature for 5 hours to obtain a polyamic acid solution (E1). The polyamic acid contained had a number average molecular weight of 10,500 and a weight average molecular weight of 26,000.
Next, the polyamic acid solution (A1) (2.0 g) obtained in Synthesis Example 1 and the polyamic acid solution (E1) (8.0 g) were mixed at room temperature for 3 hours to obtain a vertically aligned liquid crystal alignment film. A liquid crystal aligning agent (E2) that can be formed was prepared.

<Synthesis Example 6>
CBDA (2.498 g, 12.74 mmol) and DAM-7 (3.670 g, 13.0 mmol) were mixed in NMP (34.96 g) and reacted at room temperature for 20 hours to obtain a polyamic acid solution. NMP (30.84 g) and BC (30.84 g) were added to this polyamic acid solution, diluted to 6% by mass, and stirred at room temperature for 5 hours to obtain a polyamic acid solution (F1). The polyamic acid contained had a number average molecular weight of 10,800 and a weight average molecular weight of 23,000.
Next, the liquid crystal aligning agent (A1) (2.0 g) obtained in Synthesis Example 1 and the polyamic acid solution (F1) (8.0 g) are mixed at room temperature for 3 hours to form a vertical alignment liquid crystal alignment film. The liquid crystal aligning agent (F2) which can do was prepared.

<Synthesis Example 7>
BODA (2.439 g, 9.75 mmol), DAM-2 (1.295 g, 6.5 mmol), m-PDA (0.422 g, 3.9 mmol), and PCH (0.990 g, 2.6 mmol) were added to NMP. (16.1 g), the mixture was reacted at 80 ° C. for 5 hours, CBDA (0.535 g, 2.7 mmol) and NMP (8.05 g) were added, and the mixture was reacted at 40 ° C. for 10 hours. A solution was obtained. After adding NMP to this polyamic acid solution (36.0 g) and diluting to 6% by mass, acetic anhydride (6.31 g) and pyridine (1.95 g) were added as an imidization catalyst and reacted at 100 ° C. for 3 hours. It was. This reaction solution was poured into methanol (350 ml), and the resulting precipitate was filtered off. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (G). The imidation ratio of this polyimide was 76%, the number average molecular weight was 14,000, and the weight average molecular weight was 46000.

NMP (14.6 g) was added to the obtained polyimide powder (G) (3.0 g), and dissolved by stirring at 70 ° C. for 5 hours. NMP (17.4g) and BC (15.0g) were added to this solution, and the polyimide solution (G1) was obtained by stirring.
Next, the polyamic acid solution (A1) (2.0 g) obtained in Synthesis Example 1 and the polyimide solution (G1) (8.0 g) were mixed at room temperature for 3 hours to obtain a vertically aligned liquid crystal alignment film. A liquid crystal aligning agent (G2) that can be formed was prepared.

<Comparative Synthesis Example 1>
CBDA (2.447 g, 12.48 mmol) and DAM-5 (2.603 g, 13.0 mmol) were mixed in NMP (28.62 g) and reacted at room temperature for 20 hours to obtain a polyamic acid solution. NMP (22.38 g) and BC (22.38 g) were added to this polyamic acid solution, diluted to 6% by mass, and stirred at room temperature for 5 hours to obtain a polyamic acid solution (H1). The polyamic acid contained had a number average molecular weight of 11,000 and a weight average molecular weight of 29000.
Next, the polyamic acid solution (A1) (2.0 g) obtained in Synthesis Example 1 and the polyamic acid solution (H1) (8.0 g) were mixed at room temperature for 3 hours to obtain a vertically aligned liquid crystal alignment film. A liquid crystal aligning agent (H2) that can be formed was prepared.

<Comparative Synthesis Example 2>
CBDA (2.498 g, 12.74 mmol) and DAM-6 (1.978 g, 13.0 mmol) were mixed in NMP (25.37 g) and reacted at room temperature for 20 hours to obtain a polyamic acid solution. NMP (22.38 g) and BC (22.38 g) were added to this polyamic acid solution, diluted to 6% by mass, and stirred at room temperature for 5 hours to obtain a polyamic acid solution (I1). The polyamic acid contained had a number average molecular weight of 11,000 and a weight average molecular weight of 28,000.
Next, the polyamic acid solution (A1) (2.0 g) obtained in Synthesis Example 1 and this polyamic acid solution (I1) (8.0 g) were mixed at room temperature for 3 hours to obtain a vertically aligned liquid crystal alignment film. The liquid crystal aligning agent (I2) which can form is prepared.

<Example 1>
Using the liquid crystal aligning agent (C2) obtained in Synthesis Example 3, a liquid crystal cell was prepared according to the procedure shown below.

[Production of liquid crystal cell]
The liquid crystal aligning agent (C2) obtained in Synthesis Example 3 was spin-coated on the transparent electrode forming surface of a glass substrate with a transparent electrode made of an ITO film, dried on an 80 ° C. hot plate for 90 seconds, and then heated at 200 ° C. Firing was performed in a circulation oven for 30 minutes to form a liquid crystal alignment film having a thickness of 50 nm.

  This substrate was irradiated with 20 mJ of 313 nm linearly polarized light UV (ultraviolet light) having an irradiation intensity of 11.0 mW / cm. The direction of the incident light was inclined by 40 ° with respect to the normal direction of the substrate. The linearly polarized light UV was adjusted by passing a 313 nm band-pass filter through the ultraviolet light of a high-pressure mercury lamp and then passing it through a 313 nm polarizing plate.

  Two substrates by the above manufacturing method were prepared, and a 6 μm bead spacer was sprayed on the liquid crystal alignment film of one substrate, and then a sealing agent was printed thereon. Next, the liquid crystal alignment surfaces of the two substrates are made to face each other, and pressure-bonded so that the projection direction of the optical axis of the linearly polarized light UV on each substrate is antiparallel, and a sealant (Kyoritsu Chemical Co., Ltd.) is taken at 150 ° C. for 105 minutes. Co., Ltd., XN-1500T) was heat cured. A negative type liquid crystal (MLC-6608, manufactured by Merck & Co., Inc.) having a negative dielectric anisotropy was injected into the empty cell thus produced by a reduced pressure injection method, thereby preparing a vertical alignment type liquid crystal cell.

  Using the same manufacturing method, five types of vertically aligned liquid crystal cells having the same structure were prepared except that the thickness of the liquid crystal alignment film was different from 70 nm, 100 nm, 120 nm, 150 nm, and 200 nm, and the following evaluations were made. Used for.

[Evaluation of pretilt angle]
The pretilt angle of the liquid crystal was measured using each of the manufactured liquid crystal cells. The pretilt angle was measured by the Mueller matrix method using an “Axo Scan” manufactured by Axo Metrix. The measurement results are summarized in Table 1.

<Example 2>
Except having changed the liquid crystal aligning agent (C2) into the liquid crystal aligning agent (C3), according to the method similar to Example 1, six types of liquid crystal cells were produced and the pretilt angle was measured about each.

<Example 3>
Except having changed the liquid crystal aligning agent (C2) into the liquid crystal aligning agent (D2), according to the same method as Example 1, six types of liquid crystal cells were produced and the pretilt angle was measured about each.

<Example 4>
Except having changed the liquid crystal aligning agent (C2) into the liquid crystal aligning agent (E2), according to the same method as Example 1, 6 types of liquid crystal cells were produced and the pretilt angle was measured for each.

<Example 5>
Except having changed the liquid crystal aligning agent (C2) into the liquid crystal aligning agent (F2), according to the same method as Example 1, six types of liquid crystal cells were produced and the pretilt angle was measured about each.

<Example 6>
Except having changed the liquid crystal aligning agent (C2) into the liquid crystal aligning agent (G2), according to the same method as Example 1, six types of liquid crystal cells were produced and the pretilt angle was measured for each.

<Comparative Example 1>
Six types of liquid crystal cells were prepared in the same manner as in Example 1 except that the polyamic acid solution (A1) was used as the liquid crystal aligning agent (A1) and the liquid crystal aligning agent (C2) was changed to the liquid crystal aligning agent (A1). The pretilt angle was measured for each.

<Comparative example 2>
Using the polyimide solution (B1) as the liquid crystal aligning agent (B1) and changing the liquid crystal aligning agent (C2) to the liquid crystal aligning agent (B1), six types of liquid crystal cells were produced in the same manner as in Example 1. The pretilt angle was measured for each.

<Comparative Example 3>
Except that the liquid crystal aligning agent (C2) was changed to the liquid crystal aligning agent (H2), six types of liquid crystal cells were prepared according to the same method as in Example 1, and the pretilt angle was measured for each.

<Comparative Example 4>
Except that the liquid crystal aligning agent (C2) was changed to the liquid crystal aligning agent (I2), six types of liquid crystal cells were prepared according to the same method as in Example 1, and the pretilt angle was measured for each.

Table 1 summarizes the measurement results of the pretilt angles of the liquid crystal cells of Examples 1 to 6. Moreover, the measurement results of the pretilt angles of the liquid crystal cells of Comparative Examples 1 to 4 are shown in Table 2.
In Tables 1 and 2, for each of Examples 1 to 6 and Comparative Examples 1 to 4, the amount of change in the pretilt angle (Δφ (degrees)) due to the film thickness of the liquid crystal alignment film is described.
Δφ compares the pretilt angles of six types of liquid crystal cells having different film thicknesses of the liquid crystal alignment film in each of Examples 1 to 6 and Comparative Examples 1 to 4 to obtain the maximum pretilt angle and the minimum pretilt angle, and the difference The value evaluated as.

  FIG. 1 is a graph showing the relationship between the thickness of the alignment film of the liquid crystal cell and the pretilt angle.

  FIG. 1 shows a phenomenon in which the pretilt angle of the liquid crystal varies by changing the film thickness of the liquid crystal alignment film of the liquid crystal cell, comparing the results of Example 6 and Comparative Example 4.

As shown in Table 2 and Comparative Example 4 in FIG. 1, the photo-aligned vertical alignment liquid crystal alignment film corresponding to the prior art changes the thickness of the liquid crystal pre-tilt of the liquid crystal cell. It can be seen that the angle changes greatly. This means that UV (ultraviolet rays) at the time of photo-alignment treatment is reflected at the interface between the liquid crystal alignment film and the substrate and interferes with the surface of the liquid crystal alignment film.
Further, as shown in Table 1 and the graph of Example 6 in FIG. 1, a pretilt depending on the film thickness of the liquid crystal alignment film is obtained by mixing (blending) a material having absorption in the ultraviolet region with the liquid crystal alignment film. It can be seen that the change in corners is suppressed. The reason is that the mixed material absorbs the reflected light to suppress the interference of light on the alignment film surface.

<Example 7>
Next, using the liquid crystal cell having a film thickness of 100 nm of the liquid crystal alignment film whose pretilt angle was measured in Examples 1 to 6 and Comparative Examples 1 to 4, the liquid crystal cell was placed on a backlight for a liquid crystal panel, Aging was performed for 300 hours while irradiating light from the backlight. Thereafter, the pretilt angle of each liquid crystal cell was measured in the same manner as described above, and the change (Δθ) in the pretilt angle before and after aging was evaluated. The evaluation results are summarized in Table 3.
In Table 3, the pretilt angle of the liquid crystal cell before aging is indicated as “pretilt angle 1”, and the pretilt angle after aging is indicated as “pretilt angle 2”.

  From the evaluation results of Table 3, it was found that in Comparative Examples 1 to 4, the pretilt angle greatly changed to a high value before and after aging due to the influence of backlight light. This is because the unreacted photoreactive group that could not react with polarized UV light during the alignment treatment gradually undergoes a photoreaction by the backlight, and as a result, the anisotropy of the liquid crystal alignment film surface gradually decreases. It is understood that this is because.

  On the other hand, in the liquid crystal cell using the liquid crystal aligning agent which blended the material which has absorption in the ultraviolet region of Examples 1-6, it was confirmed that the change of the pretilt angle by backlight light is suppressed. This is because the material having absorption in the ultraviolet region blended with the liquid crystal aligning agent absorbs the ultraviolet rays generated from the backlight, and as a result, the unreacted photoreactive group involved in the alignment control ability becomes difficult to react. It is understood that it shows an effect.

  A liquid crystal display element having a liquid crystal alignment film formed using the liquid crystal aligning agent of the present invention and capable of photo-alignment treatment can be manufactured with high productivity and has excellent display characteristics. It can be suitably used as a display element for a portable information terminal such as a liquid crystal TV or a smartphone displaying a high-definition image.

  It should be noted that the entire content of the specification, claims, drawings and abstract of Japanese Patent Application No. 2012-182104 filed on August 21, 2012 is cited herein as the disclosure of the specification of the present invention. Incorporated.

Claims (10)

The has a first polymer that reacts with light in the wavelength range of 250～380Nm, possess an absorption maximum in a wavelength range of 250～380Nm, and at least one specific structure of the phenone structures and diphenylamine structure liquid crystal aligning agent characterized by containing the second polymer, the. Containing organic content before Symbol second polymer is 3 to 80 wt% of the total content in conjunction with the first polymer, liquid crystal aligning agent of claim 1.   The first polymer has a photoreactive group that reacts with light, and the photoreactive group is at least one structure selected from the group consisting of a cinnamoyl structure, a coumarin structure, and a chalcone structure. The liquid crystal aligning agent of Claim 1 or 2. The liquid crystal aligning agent of Claim 3 in which the said photoreactive group contains either of the following side chain structures.

(The broken line represents a bonding group to the main chain of the polymer.
R is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (however, any hydrogen atom may be replaced by a fluorine atom), or an alkoxyl group having 1 to 10 carbon atoms (however, any hydrogen thereof) The atom may be replaced by a fluorine atom).
A and B each independently represent a single bond or a ring structure represented by the following formula.

Each T independently represents a single bond, an ether, an ester, an amide or a ketone bond. S represents a single bond or an alkylene group having 1 to 10 carbon atoms.
However, when S and A are both single bonds, oxygen atoms are not adjacent to each other. ) The liquid crystal aligning agent of any one of Claims 1-4 whose said specific structure is any structure represented by a following formula.

(R represents an alkyl group having 1 to 5 carbon atoms.) The liquid crystal alignment according to any one of claims 1 to 5 , wherein the first polymer is at least one polymer selected from the group consisting of polyamic acid and polyimide obtained by imidizing the polyamic acid. Agent. The second contains a polymer, the polymer of the second is at least one polymer selected from the group consisting of the resulting polyimide by imidization of the polyamic acid and the polyamic acid according to claim 1-6 The liquid crystal aligning agent of any one of these. A liquid crystal alignment film obtained from the liquid crystal aligning agent according to claim 1.   The liquid crystal aligning film of Claim 8 whose film thickness is 5-300 nm. A liquid crystal display element comprising the liquid crystal alignment film according to claim 8 .

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