JP6460341B2 - Liquid crystal display element and method for manufacturing liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal display element provided with a liquid crystal material containing a polymerizable compound and a method for producing the liquid crystal display element.

  As a liquid crystal display element used for a liquid crystal television, a liquid crystal display, and the like, an MVA (Multi-domain Vertical Alignment) system excellent in viewing angle characteristics is known (see, for example, Patent Document 1). In the MVA system, a liquid crystal having negative dielectric anisotropy is vertically aligned by forming protrusions and slits on the substrate and display electrodes for controlling the direction in which the liquid crystal falls. According to this MVA method, the liquid crystal alignment can be controlled in a plurality of different directions without applying a rubbing treatment to the liquid crystal alignment film. However, since the liquid crystal is inclined in order from the liquid crystal near the protrusion, the propagation of the liquid crystal It takes time to reduce the response speed.

  As a technique for improving the response speed, a PSA system (Polymer Sustained Alignment) is known. In the PSA method, a polymerizable compound that is polymerized by light or heat is added to a liquid crystal, and after manufacturing a liquid crystal cell, ultraviolet rays are irradiated in a state where the liquid crystal is tilted while applying an electric field. As a result, the polymerizable compound is polymerized or crosslinked, and the liquid crystal is aligned in the tilt direction (see, for example, Patent Document 2). In this PSA system, the liquid crystal tilts all at once, so that the response speed is faster than in the MVA system. Furthermore, since the rubbing process is unnecessary in the PSA method, problems such as scratches on the surface of the liquid crystal alignment film, dust generation, mechanical force and static electricity caused by the rubbing process do not occur.

  On the other hand, a photo-alignment method is known as a technique that has a high response speed and does not perform a rubbing process (see, for example, Patent Document 3). In the photo-alignment method, the alignment direction of the liquid crystal is fixed by causing a photoreaction such as a photolysis reaction or a photodimerization reaction to occur in the polymer contained in the liquid crystal alignment film by irradiation with polarized ultraviolet rays. In such a photo-alignment method, liquid crystal display elements of IPS (In-Plane Switching) or FFS (Fringe Field Switching) liquid crystal are used as liquid crystal display elements are demanded for higher definition and higher quality. Application to display elements is performed (for example, see Patent Document 3). As for the IPS system, in recent years, a technique combined with the PSA system has been developed in order to further improve the orientation ability.

  However, the solubility of the polymerizable compound added to the liquid crystal material in the PSA method is low, and there is a problem in that an unreacted polymerizable compound remains as an impurity in the liquid crystal material. When the unreacted polymerizable compound remains, there arises a problem that desired light sensitivity cannot be obtained and the alignment ability of the liquid crystal is not sufficiently exhibited. Further, there arises a problem that afterimages are generated unless desired light sensitivity is obtained. In order to increase the sensitivity of light, it is necessary to lengthen the conjugation of the polymerizable compound to increase the absorption to the longer wavelength side of ultraviolet rays, and the mesogenic structure becomes larger or the ring structure or the like is rigid. Due to the increase in structure, there arises a problem that the solubility in the liquid crystal material further decreases.

JP 2010-097226 A JP 2004-302061 A JP2013-080193A

  In view of such circumstances, an object of the present invention is to provide a liquid crystal display element having a highly sensitive alignment fixing ability and suppressing the occurrence of an afterimage and a method for manufacturing the liquid crystal display element.

  As a result of intensive studies, the present inventors have found that a polymerizable compound that forms a mesogenic structure between molecules via a functional group has high solubility in liquid crystals, and completed the present invention. Thus, the present invention has the following gist.

(1) A pair of substrates facing each other, a liquid crystal layer sandwiched between the substrates, a liquid crystal alignment film obtained from a liquid crystal alignment agent containing a polymer on at least one liquid crystal layer side of the substrate, The liquid crystal layer is formed of a liquid crystal composition containing a polymerizable compound and a liquid crystal, and the polymerizable compound has a polymerizable unsaturated bond group and a functional group capable of hydrogen bonding. And at least one aromatic ring in the vicinity of the functional group, and the functional group forms a mesogen structure by forming a hydrogen bond between molecules.

(2) The liquid crystal display element according to (1), wherein the functional group is a carboxyl group.

(3) The liquid crystal display element according to (1) or (2), wherein the polymerizable compound is at least one selected from the following formulas [1-1] to [1-4]: .

（Ｔはエーテル、エステル、アミド結合、Ｓは炭素原子数２〜１１のアルキレン基、Ｒは水素原子もしくはメチル基、ｎ＝１もしくは２）

(T is an ether, ester, amide bond, S is an alkylene group having 2 to 11 carbon atoms, R is a hydrogen atom or a methyl group, n = 1 or 2)

(4) The liquid crystal according to any one of (1) to (3), wherein the polymerizable compound is at least one selected from the following formulas [2-1] to [2-3]. Display element.

(5) The liquid crystal display element according to any one of (1) to (4), wherein the polymer has a group in the side chain that vertically aligns the liquid crystal.

(6) The liquid crystal display element according to (5), wherein the polymer further has a photopolymerizable group in a side chain.

(7) The liquid crystal display element according to (6), wherein the photopolymerizable group is at least one selected from the following formulas [3-1] to [3-7].

（式中、Ｍｅはメチル基を表す。）

(In the formula, Me represents a methyl group.)

(8) The liquid crystal display element according to any one of (1) to (4), wherein the polymer has a photoreactive group.

(9) The liquid crystal display element according to (8), wherein the photoreactive group is at least one selected from the following formulas [4-1] to [4-5].

(10) The above-mentioned (1) to (9), wherein the polymer contains at least one selected from a polyimide precursor and a polyimide obtained by imidizing it, polysiloxane or poly (meth) acrylate. The liquid crystal display element according to any one of the above.

(11) The liquid crystal display element according to any one of the above (5) to (7), comprising a liquid crystal cell produced by irradiating ultraviolet rays while applying a voltage to the liquid crystal layer.

(12) The liquid crystal display device as described in (8) or (9) above, comprising a liquid crystal cell produced by irradiating the liquid crystal layer with polarized ultraviolet rays.

(13) A liquid crystal alignment film is formed from a liquid crystal aligning agent containing a polymer on at least one of the pair of substrates, and the pair of substrates are arranged to face each other so that the liquid crystal alignment film is on the inside. A polymerizable unsaturated bond group, a functional group that forms a mesogen structure by forming a hydrogen bond between molecules, a polymerizable compound having at least one aromatic ring in the vicinity of the functional group, and a liquid crystal A liquid crystal composition comprising the above is formed to form a liquid crystal layer, and the liquid crystal layer is irradiated with ultraviolet rays to polymerize the polymerizable compound.

  ADVANTAGE OF THE INVENTION According to this invention, it has a highly sensitive orientation fixing ability, and the manufacturing method of a liquid crystal display element and generation | occurrence | production of an afterimage were suppressed are implement | achieved.

The present invention is described in detail below.
The present invention relates to a liquid crystal display element driven by a PSA method, which includes a liquid crystal layer obtained from a liquid crystal composition containing a liquid crystal and a polymerizable compound.

<Polymerizable compound>
A liquid crystal composition for producing a liquid crystal layer contains a liquid crystal and a polymerizable compound. The polymerizable compound has a polymerizable unsaturated bond group, a functional group capable of hydrogen bonding, and at least one aromatic ring in the vicinity of the functional group, and the functional group forms a hydrogen bond between molecules, thereby forming a mesogen. Form a structure.

  The polymerizable unsaturated bond group means an ethylenically unsaturated double bond group that contributes to photopolymerization or photocrosslinking reaction by stimulation such as heat or ultraviolet rays. Specific examples include radically polymerizable groups such as vinyl group, (meth) acryloyl group and isopropenyl group, allyl group, styryl group, and α-methylene-γ-butyllactone group.

  In addition, the hydrogen bond according to the present invention is a solvent for a liquid crystal aligning agent because of a bias of electrons caused by a difference in electronegativity between a hydrogen atom in a functional group and an atom having high electronegativity adjacent to the hydrogen atom. A bond in which hydrogen atoms cause attractive interaction with other atoms having a high electronegativity in a liquid crystal alignment film or in a liquid crystal alignment film and are formed through hydrogen atoms between molecules. The functional group capable of hydrogen bonding refers to a group that forms a hydrogen bond between molecules in a liquid crystal alignment film or a solvent of a liquid crystal alignment agent. Such a functional group capable of hydrogen bonding mainly forms a dimer between molecules in a liquid crystal alignment film or a solvent of a liquid crystal alignment agent. Since such a polymerizable compound has a highly polar group such as a carboxyl group and a hydroxyl group, the solubility is very high as compared with a normal polymerizable compound. For this reason, the solubility of the polymerizable compound in the solvent is improved, and precipitation of the polymerizable compound hardly occurs even when the liquid crystal aligning agent is stored (for example, frozen storage).

  Furthermore, the functional group capable of hydrogen bonding forms a mesogenic structure by forming a hydrogen bond between molecules. The mesogenic structure means a rigid structure for exhibiting liquid crystallinity. By forming such a mesogen structure via a hydrogen bond, that is, formation of a rigid structure, the sensitivity of the liquid crystal layer to light is increased and the alignment fixing ability is improved.

  The functional group capable of hydrogen bonding is not particularly limited, and examples thereof include a carboxyl group, a hydroxyl group, a urea group, an amide group, and an imide group. Among these, a carboxyl group is preferable in view of easy formation of a dimer.

  In addition, since at least one or more aromatic rings included in the polymerizable compound are rigid, the mesogenic structure is formed together with the functional group by being located in the vicinity of the functional group to be hydrogen bonded. Since these mesogenic structures have pseudo-huge mesogenic structures, conjugation is widened, and absorption is performed up to the ultraviolet region (for example, up to 365 nm) on the long wavelength side. For this reason, the sensitivity becomes high even for ultraviolet irradiation with a long wavelength, and the alignment can be fixed even with ultraviolet irradiation with weak energy. Examples of the aromatic ring include hydrocarbon aromatic rings such as benzene ring, naphthalene ring and anthracene ring, and heteroaromatic rings such as pyridine ring, pyrazine ring and pyrrole ring. The number of aromatic rings is not particularly limited, and is preferably 1 to 4. These aromatic rings may have a substituent.

  As an example of the polymerizable compound described above, a polymerizable compound represented by the above formulas [1-1] to [1-4] or the above formulas [2-1] to [2-3] having a carboxyl group. Is mentioned. Since the difference in electronegativity between the hydrogen atom of the carboxyl group and the oxygen atom adjacent to this hydrogen atom is large, by using these polymerizable compounds, a dimer is formed through a stronger hydrogen bond between molecules. Is formed. Since the molecule of such a polymerizable compound is very small, each molecule of the dimer is also very small. Thereby, the solubility of the polymerizable compound in the solvent is further improved, and the sensitivity of the liquid crystal alignment film to light is further increased. The polymerizable compounds represented by the above formulas [1-1] to [1-4] and the above formulas [2-1] to [2-3] have a mesogenic structure in the vicinity of the carboxyl group together with the carboxyl group. Having two or more aromatic rings. Thereby, the sensitivity with respect to the light of a liquid crystal aligning film becomes still higher, and alignment fixing ability improves more.

  In addition, what is necessary is just to make it the addition ratio of the polymeric compound added to a liquid crystal so that a polymeric compound may be 0.05-1.0 mass% with respect to a liquid crystal, for example. In addition, you may add a polymeric compound to a liquid crystal aligning agent, and it is preferable that the addition ratio is 0.1-30 (mass)% with respect to a liquid crystal aligning agent.

<LCD>
The liquid crystal layer is obtained from a liquid crystal composition containing a liquid crystal and the polymerizable compound. As the liquid crystal, various liquid crystals such as a known nematic liquid crystal and smectic liquid crystal can be used. Some nematic liquid crystals have negative or positive dielectric anisotropy. Examples of the nematic liquid crystal having negative dielectric anisotropy include dicyanobenzene liquid crystal, pyridazine liquid crystal, Schiff base liquid crystal, azoxy liquid crystal, naphthalene liquid crystal, biphenyl liquid crystal, and phenylcyclohexane liquid crystal. Examples of nematic liquid crystals having positive dielectric anisotropy include biphenyl liquid crystals, phenyl cyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals, biphenyl cyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, Examples include Cuban liquid crystal. Examples of the smectic liquid crystal include a ferroelectric liquid crystal and an antiferroelectric liquid crystal.

<Liquid crystal aligning agent>
The liquid crystal layer is produced on the liquid crystal alignment film. The liquid crystal aligning agent for producing the liquid crystal aligning film contains a polymer and a solvent for dissolving the polymer. The liquid crystal aligning agent is 1) a vertical alignment method produced by irradiating ultraviolet rays while applying a voltage to a liquid crystal cell, that is, a liquid crystal display element of a vertical electric field driving method, or 2) polarized ultraviolet rays (polarized ultraviolet rays). After passing through the step of irradiating, a liquid crystal cell is produced, and a horizontal alignment method such as an IPS method (In-Plane Switching) or FFS method (Fringe Field Switching) produced by irradiating the liquid crystal cell with ultraviolet rays, that is, It is used for a liquid crystal display element of a horizontal electric field drive system.

  A liquid crystal aligning agent used in a vertical alignment type liquid crystal display element contains a polymer having a side chain having a group for vertically aligning liquid crystals as a polymer. Further, these polymers may have a photoreactive group or a photoradical generating group in the side chain. When a polymer having such a photoreactive group or photoradical generating group in the side chain is used, photopolymerization or photocrosslinking reaction due to ultraviolet irradiation is more likely to occur, and the alignment and fixing ability is improved.

  The liquid crystal aligning agent in the case of being used for a horizontal alignment type liquid crystal display element may have a photoreactive group as a polymer. By having a photoreactive group, a photoreaction such as a photoisomerization reaction caused by irradiation with polarized ultraviolet rays occurs, and a horizontal alignment ability is imparted to the liquid crystal alignment film even without a rubbing treatment (so-called photoalignment). Hereinafter, a group for vertically aligning the liquid crystal, a photopolymerizable group, and a photoreactive group will be described.

<Group for aligning liquid crystal vertically>
When the liquid crystal display element is of a vertical alignment type, the polymer contained in the liquid crystal aligning agent has a group for vertically aligning the liquid crystal in the side chain. The group for aligning the liquid crystal vertically is a group having the ability to align liquid crystal molecules vertically with respect to the substrate, and the structure is not particularly limited as long as it has this ability. Examples of the group for vertically aligning the liquid crystal include a linear alkyl group, a linear fluoroalkyl group, a cyclic group having an alkyl group or a fluoroalkyl group at the terminal, and a steroid group. Specific examples include groups represented by the following formula [5].

R ¹ is an alkylene group having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms, —O—, —COO—, —OCO—, —NHCO—, —CONH—, or an alkylene ether group having 1 to 3 carbon atoms. (—C—C—O—) is represented. Among these, from the viewpoint of ease of synthesis, —O—, —COO—, —CONH—, or an alkylene ether group having 1 to 3 carbon atoms is preferable. R ² , R ³ and R ⁴ each independently represent a phenylene group or a cycloalkylene group. The combination of a, b, c, R ² , R ³ and R ⁴ shown in Table 1 is preferable from the viewpoint of ease of synthesis and ability to orient the liquid crystal vertically.

R ⁵ represents a hydrogen atom, an alkyl group having 2 to 24 carbon atoms, preferably 5 to 8 carbon atoms or a fluorine-containing alkyl group, an aromatic ring, an aliphatic ring, a heterocyclic ring, or a macrocyclic group composed of these. When at least one of a, b and c is 1, the structure of R ⁵ is preferably a hydrogen atom, an alkyl group having 2 to 14 carbon atoms, or a fluorine-containing alkyl group having 2 to 14 carbon atoms, and more Preferably, it represents a hydrogen atom, an alkyl group having 2 to 12 carbon atoms, preferably 2 to 10 carbon atoms, or a fluorine-containing alkyl group.

When a, b and c are all 0, the structure of R ⁵ is preferably an alkyl group having 12 to 22 carbon atoms, preferably 12 to 20 carbon atoms or a fluorine-containing alkyl group, an aromatic ring, an aliphatic ring, a hetero ring. It is a ring or a macrocyclic group comprising these, more preferably an alkyl group having 12 to 20 carbon atoms, preferably 12 to 18 carbon atoms or a fluorine-containing alkyl group.

  The side chain of the group that orients the liquid crystal vertically may be directly bonded to the main chain of the polymer, or may be bonded through an appropriate bonding group. Thus, the method for introducing the group for vertically aligning the liquid crystal into the side chain is not particularly limited.

  In addition, the amount of the group that vertically aligns the liquid crystal is preferably within a range in which the alignment can be fixed, and other characteristics are not affected in order to further improve the sensitivity to light and the alignment fixing ability. In the range, as much as possible is preferable.

<Photopolymerizable group>
The polymer contained in the liquid crystal aligning agent may further have a photopolymerizable group in the side chain. The photopolymerizable group is a group that undergoes a polymerization reaction by light such as ultraviolet rays, for example, a group that is polymerized by light such as ultraviolet rays (hereinafter also referred to as a photopolymerizable group) or a photocrosslinkable group (hereinafter also referred to as a photocrosslinkable group). If it says, it will not specifically limit, However, At least 1 sort (s) chosen from the photopolymerizable group represented by the said Formula [3-1]-[3-7] is used preferably.

  A liquid crystal alignment film obtained using a liquid crystal aligning agent containing such a polymer contains a photopolymerizable group. When a liquid crystal display element containing a photopolymerizable group in the liquid crystal alignment film is irradiated with light such as ultraviolet rays, the photopolymerizable group located on the surface where the liquid crystal alignment film and the liquid crystal are in contact with each other, or the polymerizable property of the above-described polymerizable compound The unsaturated bonding group causes photopolymerization or photocrosslinking reaction, and the alignment of the liquid crystal positioned on the surface of the liquid crystal alignment film is more efficiently fixed.

  The photopolymerizable group introduced into the side chain of the polymer (hereinafter also referred to as photopolymerizable side chain) is a methacryl group, an acrylic group, a vinyl group, an allyl group, a styryl group, and an α-methylene-γ-butyrolactone group. A side chain containing at least one selected from is preferred.

  Such a photopolymerizable side chain may be directly bonded to the main chain of the polymer, or may be bonded via an appropriate bonding group. Thus, the method for introducing the photopolymerizable side chain is not particularly limited. Examples of the photopolymerizable side chain include those represented by the following formula [6].

In the formula [6], R ⁶ represents a single bond or —CH ₂ —, —O—, —COO—, —OCO—, —NHCO—, —CONH—, —NH—, —CH ₂ O—, —N ( CH ₃ ) —, —CON (CH ₃ ) —, —N (CH ₃ ) CO—, wherein R ⁷ is a single bond, unsubstituted or substituted with a fluorine atom, 20 represents an alkylene group, and —CH ₂ — of the alkylene group may be optionally replaced by —CF ₂ — or —CH═CH—, and when any of the following groups is not adjacent to each other: These groups may be substituted. -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, a divalent carbocycle, and a divalent heterocycle. R ⁸ represents a methacryl group, an acryl group, a vinyl group, an allyl group, a styryl group, and an α-methylene-γ-butyrolactone group.

In addition, R ⁶ in the above formula [6] can be formed by an ordinary organic synthetic method, but from the viewpoint of ease of synthesis, —CH ₂ —, —O—, —COO—, —NHCO. _{-, - NH -, - CH} 2 O- are preferable.

Specific examples of the divalent carbocycle or divalent heterocycle carbocycle or heterocycle that replaces any —CH ₂ — in R ⁷ include the following structures, but are not limited thereto. Is not to be done.

R ⁸ is preferably a methacryl group, an acrylic group, a vinyl group or an α-methylene-γ-butyrolactone group from the viewpoint of photopolymerization.

  The abundance of the photopolymerizable side chain is preferably within a range where the alignment can be fixed by reacting with irradiation of light such as ultraviolet rays to form a covalent bond, and the sensitivity to light and the alignment fixing ability are further improved. In order to achieve this, as much as possible is preferable as long as other characteristics are not affected.

<Photoreactive group>
In the case of a horizontal alignment method such as an IPS method or an FFS method in which a liquid crystal display element is irradiated with polarized ultraviolet rays, the polymer containing the liquid crystal aligning agent is a photoreaction that exhibits liquid crystal alignment ability by using polarized ultraviolet rays. It is preferable that a sex group is introduced.

  By irradiating polarized ultraviolet rays to a liquid crystal alignment film obtained from a liquid crystal aligning agent containing a polymer having a photoreactive group introduced, a photoreaction progresses and is the same as the polarization direction or perpendicular to the polarization direction. Anisotropy is imparted in the direction, and the liquid crystal is aligned. Photoreaction includes photodimerization and photoisomerization. As the photoreactive group, those having an unsaturated bond, particularly a double bond, are preferable, and examples thereof include an acrylic group, a vinyl group, a methacryl group, an anthracenyl group, a calconyl group, a coumarin group, a stilbene group, a maleimide group, and a cinnamoyl group. It is done.

  If a specific example is given, the structure represented by the above formulas [4-1] to [4-3] may be mentioned as the structure in which the photodimerization reaction proceeds. In addition, examples of the structure in which the photoisomerization reaction proceeds include structures represented by the above formulas [4-4] and [4-5]. The photoreactive group having a structure selected from the above formulas [4-1] to [4-5] is an arbitrary number of H from the structures of the formulas [4-1] to [4-5]. A group in which O is a bond in the above formula [4-1], or a group in which these structures are bonded to other structures (such as an alkylene group).

  In addition, such a photoreactive group may be introduced into the main chain of the polymer or may be introduced into the side chain. Thus, the method for introducing the photoreactive group is not particularly limited. Further, the polymer may have a group that vertically aligns the liquid crystal together with the photoreactive group.

  The abundance of the photoreactive group is preferably within a range where the photoreaction can be caused and the orientation can be fixed. In order to further improve the sensitivity to light and the ability to fix the orientation, other properties are affected. As much as possible is preferable as long as it does not come out.

<Polymer>
The polymer contained in the liquid crystal aligning agent is preferably a polyimide precursor, a polyimide obtained by imidizing it, or a polysiloxane or poly (meth) acrylate. Here, the polyimide precursor refers to polyamic acid (also referred to as polyamic acid) or polyamic acid ester. In addition, these different polymers may be simultaneously contained in the liquid crystal aligning agent, and the content ratio thereof is variously selected according to the characteristics of the liquid crystal display element. The total amount of the polymer contained in the liquid crystal aligning agent is preferably 0.1 to 20 (mass)%. The polyimide precursor, polyimide, polymer such as polysiloxane or poly (meth) acrylate contained in the liquid crystal aligning agent needs to be soluble in the solvent contained in the liquid crystal aligning agent. Each polymer will be described below.

<Polyimide precursor and polyimide obtained by imidizing it>
When the polymer which a liquid crystal aligning agent contains a polyimide precursor, a polyimide precursor has a repeating unit (structural unit) represented, for example by following formula [7].

In Formula [7], R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. From the viewpoint of ease of imidization by heating, a hydrogen atom or a methyl group is particularly preferable. X ₂ is a tetravalent organic group, and its structure is not particularly limited. If a specific example is given, following formula [X-1]-[X-43] will be mentioned. From the viewpoint of liquid crystal alignment, X ₂ is preferably [X-1] to [X-10], [X-26] to [X-28], or [X-31] to [X-37].

In formula [X-1], R ₂ , R ₃ , R ₄ and R ₅ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms. , An alkenyl group, or a phenyl group. From the viewpoint of liquid crystal orientation, R ₂ , R ₃ , R ₄ and R ₅ are preferably a hydrogen atom, a halogen atom, a methyl group or an ethyl group, more preferably a hydrogen atom or a methyl group, and still more preferably It is at least one selected from the group consisting of the structures represented by [X1-1] to [X1-2].

When the liquid crystal aligning agent is used for a liquid crystal display device produced by irradiating polarized ultraviolet rays, preferred structures of X ₂ include [X1-1], [X1-2], [X-2], [X -3], [X-5], [X-6], [X-7], [X-8], [X-9], [X-10], and [X1-1], [X-10] X1-2] and [X-6] are particularly preferred.

In the formula [7], Y ₂ is a divalent organic group, the structure thereof is not particularly limited. If Y ₂ Specific examples include the following formula [Y-1] ~ [Y -73].

（式中、Ｍｅはメチル基を表す。）

(In the formula, Me represents a methyl group.)

  Since the improvement of the solubility with respect to organic solvents, such as a polyimide precursor and a polyimide, can be anticipated, [Y-8], [Y-20], [Y-21], [Y-22], [Y-28], [ It is preferable to have a structural unit having a structure of Y-29] or [Y-30].

  The polyimide precursor contained in the liquid crystal aligning agent includes a diamine component (for example, a diamine having a side chain for vertically aligning a liquid crystal described later, a diamine having a photopolymerizable side chain, or a diamine having a photoreactive group) and It can be obtained by reaction with a tetracarboxylic dianhydride component (for example, tetracarboxylic dianhydride, tetracarboxylic diester dichloride, tetracarboxylic diester, etc. described later). Examples of the polyimide precursor include polyamic acid and polyamic acid ester. Specifically, a polyamic acid is obtained by reaction of a diamine component and tetracarboxylic dianhydride. The polyamic acid ester can be obtained by reacting the diamine component and tetracarboxylic acid diester dichloride in the presence of a base, or reacting the diamine component and tetracarboxylic acid diester in the presence of a suitable condensing agent or base. Polyimide can be obtained by dehydrating and ring-closing this polyamic acid or by heating and ring-closing the polyamic acid ester. Any of such polyamic acid, polyamic acid ester, and polyimide is useful as a polymer for obtaining a liquid crystal alignment film.

<Diamines with side chains that align liquid crystals vertically>
When the liquid crystal aligning agent is used in a vertical alignment type liquid crystal display element, the diamine component that is a raw material of the polyimide precursor contained in the liquid crystal aligning agent needs to have a side chain that vertically aligns the liquid crystal. .

  Examples of the diamine having a side chain for vertically aligning the liquid crystal include a long chain alkyl group, a group having a ring structure or a branched structure in the middle of the long chain alkyl group, a hydrocarbon group such as a steroid group, and the hydrogen of these groups. A diamine having a group in which a part or all of the atoms are replaced with fluorine atoms as a side chain, for example, a diamine having a side chain represented by the above formula [5] can be mentioned. More specifically, for example, a diamine having a hydrocarbon group having 8 to 30 carbon atoms in which a hydrogen atom may be substituted with fluorine, or a diamine represented by the following formulas [8] to [11] is given. However, the present invention is not limited to this.

（式［８］中のａ、ｂ、ｃ、Ｒ^１〜Ｒ^５の定義は、上記式［５］と同じである。

(The definitions of a, b, c, and R ^{1 to} R ⁵ in Formula [8] are the same as those in Formula [5] above.

（式［９］及び式［１０］中、Ａ_１０は−ＣＯＯ−、−ＯＣＯ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−ＣＨ_２−、−Ｏ−、−ＣＯ−、又は−ＮＨ−を表し、Ａ_１１は単結合若しくはフェニレン基を表し、ａ_１０は上記式［５］で表される液晶を垂直に配向させる側鎖と同一の構造を表し、ａ_１０’は上記式［５］で表される液晶を垂直に配向させる側鎖と同一の構造から水素等の元素が一つ取れた構造である二価の基を表す。）

(In Formula [9] and Formula [10], A ₁₀ represents —COO—, —OCO—, —CONH—, —NHCO—, —CH ₂ —, —O—, —CO—, or —NH—. , A ₁₁ represents a single bond or a phenylene group, a ₁₀ represents the same structure as the side chain for vertically aligning the liquid crystal represented by the above formula [5], and a ₁₀ ′ represents the above formula [5]. (This represents a divalent group having a structure in which one element such as hydrogen is removed from the same structure as the side chain for vertically aligning the liquid crystal.)

（式［１１］中、Ａ_１４は、フッ素原子で置換されていてもよい、炭素数３〜２０のアルキル基であり、Ａ_１５は、１，４−シクロへキシレン基、又は１，４−フェニレン基であり、Ａ_１６は、酸素原子、又は−ＣＯＯ−＊（ただし、「＊」を付した結合手がＡ_１５と結合する）であり、Ａ_１７は酸素原子、又は−ＣＯＯ−＊（ただし、「＊」を付した結合手が（ＣＨ_２）ａ_２と結合する。）である。また、ａ_１は０、又は１の整数であり、ａ_２は２〜１０の整数であり、ａ_３は０、又は１の整数である。）

(In the formula [11], A ₁₄ is an alkyl group having 3 to 20 carbon atoms which may be substituted with a fluorine atom, and A ₁₅ is a 1,4-cyclohexylene group or 1,4- A phenylene group, A ₁₆ is an oxygen atom or —COO— * (where a bond marked with “*” is bonded to A ₁₅ ), and A ₁₇ is an oxygen atom or —COO — * ( However, "*" is a bond marked with a _(CH 2) binds to _{a 2.).} Further, _{a 1} is 0, or an integer 1, _{a 2} is an integer from 2 to 10, a ₃ is 0 or an integer of 1.

The bonding position of the two amino groups (—NH ₂ ) in Formula [8] is not limited. Specifically, with respect to the linking group of the side chain, 2, 3 position, 2, 4 position, 2, 5 position, 2, 6 position, 3, 4 position on the benzene ring, 3, 4 position, 5 positions. Among these, from the viewpoint of reactivity when synthesizing a polyamic acid, positions 2, 4, 2, 5, or 3, 5 are preferable. Considering the ease in synthesizing the diamine, the positions 2, 4 or 3, 5 are more preferable.

  Specific examples of the structure of the formula [8] include diamines represented by the following formulas [A-1] to [A-24], but are not limited thereto.

（式［Ａ−１］〜式［Ａ−５］中、Ａ_１は、炭素数２〜２４のアルキル基又はフッ素含有アルキル基である。）

(In Formula [A-1] to Formula [A-5], A ₁ is an alkyl group having 2 to 24 carbon atoms or a fluorine-containing alkyl group.)

（式［Ａ−６］及び式［Ａ−７］中、Ａ_２は、−Ｏ−、−ＯＣＨ_２−、−ＣＨ_２Ｏ−、−ＣＯＯＣＨ_２−、又は−ＣＨ_２ＯＣＯ−を示し、Ａ_３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。）

(In Formula [A-6] and Formula [A-7], A ₂ represents —O—, —OCH ₂ —, —CH ₂ O—, —COOCH ₂ —, or —CH ₂ OCO—, and ₃ is an alkyl group having 1 to 22 carbon atoms, an alkoxy group, a fluorine-containing alkyl group or a fluorine-containing alkoxy group.

（式［Ａ−８］〜式［Ａ−１０］中、Ａ_４は、−ＣＯＯ−、−ＯＣＯ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−ＣＯＯＣＨ_２−、−ＣＨ_２ＯＣＯ−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、又は−ＣＨ_２−を示し、Ａ_５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。）

(In formula [A-8] to formula [A-10], A ₄ represents —COO—, —OCO—, —CONH—, —NHCO—, —COOCH ₂ —, —CH ₂ OCO—, —CH _2. O—, —OCH ₂ —, or —CH ₂ — is shown, and A ₅ is an alkyl group having 1 to 22 carbon atoms, an alkoxy group, a fluorine-containing alkyl group, or a fluorine-containing alkoxy group.

（式［Ａ−１１］及び式［Ａ−１２］中、Ａ_６は、−ＣＯＯ−、−ＯＣＯ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−ＣＯＯＣＨ_２−、−ＣＨ_２ＯＣＯ−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＨ_２−、−Ｏ−、又は−ＮＨ−を示し、Ａ_７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。）

(In Formula [A-11] and Formula [A-12], A ₆ represents —COO—, —OCO—, —CONH—, —NHCO—, —COOCH ₂ —, —CH ₂ OCO—, —CH _2. O—, —OCH ₂ —, —CH ₂ —, —O—, or —NH— is shown, and A ₇ is fluorine group, cyano group, trifluoromethane group, nitro group, azo group, formyl group, acetyl group, acetoxy Group or hydroxyl group.)

（式［Ａ−１３］及び式［Ａ−１４］中、Ａ_８は、炭素数３〜１２のアルキル基であり、１,４−シクロヘキシレンのシス−トランス異性は、それぞれトランス異性体である。）

(In Formula [A-13] and Formula [A-14], A ₈ is an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomerism of 1,4-cyclohexylene is a trans isomer. .)

（式［Ａ−１５］及び式［Ａ−１６］中、Ａ_９は、炭素数３〜１２のアルキル基であり、１,４-シクロヘキシレンのシス−トランス異性は、それぞれトランス異性体である。）

(In the formulas [A-15] and [A-16], A ₉ is an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomerism of 1,4-cyclohexylene is a trans isomer. .)

  Specific examples of the diamine represented by the formula [9] include diamines represented by the following formulas [A-25] to [A-30], but are not limited thereto.

（式［Ａ−２５］〜式［Ａ−３０］中、Ａ_１２は、−ＣＯＯ−、−ＯＣＯ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−ＣＨ_２−、−Ｏ−、−ＣＯ−、又は−ＮＨ−を示し、Ａ_１３は炭素数１〜２２のアルキル基又はフッ素含有アルキル基を示す。）

(In the formulas [A-25] to [A-30], A ₁₂ represents —COO—, —OCO—, —CONH—, —NHCO—, —CH ₂ —, —O—, —CO—, or It shows the _{-NH-, a 13} represents an alkyl group or a fluorine-containing alkyl group having 1 to 22 carbon atoms.)

  Specific examples of the diamine represented by the formula [10] include diamines represented by the following formulas [A-31] to [A-32], but are not limited thereto.

  Among these, [A-1], [A-2], [A-3], [A-4], [A-5], [A-5], [A-5], [A-5], [A-5], [A-5], [A-5], [A-5], [A-5] The diamines of A-25], [A-26], [A-27], [A-28], [A-29], and [A-30] are preferable.

  The diamine may be used alone or in combination of two or more depending on the liquid crystal alignment properties, pretilt angle, voltage holding characteristics, accumulated charge, and the like when the liquid crystal alignment film is formed.

<Diamine having photopolymerizable side chain>
When the liquid crystal aligning agent is used for a vertical alignment type liquid crystal display element, it is preferable that a photopolymerizable side chain is introduced into the diamine component which is a raw material of the polyimide precursor contained in the liquid crystal aligning agent. Examples of the diamine having a photopolymerizable side chain include at least one selected from a methacryl group, an acrylic group, a vinyl group, an allyl group, a styryl group, and an α-methylene-γ-butyrolactone group. The diamine which has a side chain represented by this can be mentioned. More specifically, for example, diamines represented by the following general formula [12] can be exemplified, but the invention is not limited thereto.

（式［１２］中のＲ^６、Ｒ^７及びＲ^８の定義は、上記式［６］と同じである。）

(The definitions of R ⁶ , R ⁷ and R ⁸ in Formula [12] are the same as in Formula [6] above.)

The bonding position of the two amino groups (—NH ₂ ) in Formula [12] is not limited. Specifically, with respect to the linking group of the side chain, 2, 3 position, 2, 4 position, 2, 5 position, 2, 6 position, 3, 4 position on the benzene ring, 3, 4 position, 5 positions. Among these, from the viewpoint of reactivity when synthesizing a polyamic acid, positions 2, 4, 2, 5, or 3, 5 are preferable. Considering the ease in synthesizing the diamine, the positions 2, 4 or 3, 5 are more preferable.

  Specific examples of the diamine having a photopolymerizable side chain containing at least one selected from a methacryl group, an acrylic group, a vinyl group, an allyl group, a styryl group, and an α-methylene-γ-butyrolactone group are as follows. However, it is not limited to this.

（式中、Ｒ_６は−ＣＨ_２−、−Ｏ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨ−、−ＣＯ−より選ばれる基を表す。Ｒ_７は、炭素数１から炭素数３０で形成されるアルキレン基、二価の炭素環もしくは複素環であり、このアルキレン基、二価の炭素環もしくは複素環の１つまたは複数の水素原子は、フッ素原子もしくは有機基で置き換えられていてもよい。また、Ｒ_７は、次に挙げるいずれかの基が互いに隣り合わない場合において、−ＣＨ_２−がこれらの基に置き換えられていてもよい；−Ｏ−、−ＮＨＣＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨ−、−ＮＨＣＯＮＨ−、−ＣＯ−。Ｒ_８は、−ＣＨ_２−、−Ｏ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨ−、−ＣＯ−、単結合のいずれかを表す。Ｒ_９はシンナモイル基を表す。Ｒ₁₀は単結合、または、炭素数１から炭素数３０で形成されるアルキレン基、二価の炭素環もしくは複素環であり、このアルキレン基、二価の炭素環もしくは複素環の１つまたは複数の水素原子は、フッ素原子もしくは有機基で置き換えられていてもよい。また、Ｒ₁₀は、次に挙げるいずれかの基が互いに隣り合わない場合において、−ＣＨ_２−がこれらの基に置き換えられていてもよい；−Ｏ−、−ＮＨＣＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨ−、−ＮＨＣＯＮＨ−、−ＣＯ−。Ｒ₁₁はアクリル基、メタクリル基のいずれかから選ばれる光重合性基を示す。）

(Wherein R ₆ represents a group selected from —CH ₂ —, —O—, —CONH—, —NHCO—, —COO—, —OCO—, —NH—, —CO—. R ₇ represents: An alkylene group having 1 to 30 carbon atoms, a divalent carbocycle or a heterocycle, and one or more hydrogen atoms of the alkylene group, divalent carbocycle or heterocycle are a fluorine atom or R ₇ may be substituted with an organic group, and R ₇ may be substituted with —CH ₂ — when any of the following groups is not adjacent to each other: —O— , —NHCO—, —CONH—, —COO—, —OCO—, —NH—, —NHCONH—, —CO— R ₈ is —CH ₂ —, —O—, —CONH—, —NHCO—, -COO-, -OCO-, -NH-, -CO-, R ₉ represents a single bond, R ₉ represents a cinnamoyl group, R ₁₀ represents a single bond, an alkylene group having 1 to 30 carbon atoms, a divalent carbocyclic ring or a heterocyclic ring, One or more hydrogen atoms of the alkylene group, divalent carbocycle or heterocyclic ring may be replaced with a fluorine atom or an organic group, and R ₁₀ may be any of the following groups adjacent to each other: In this case, —CH ₂ — may be replaced by these groups; —O—, —NHCO—, —CONH—, —COO—, —OCO—, —NH—, —NHCONH—, — CO-. R ₁₁ represents a photopolymerizable group selected from an acrylic group and a methacryl group.)

（Ｘは単結合、又は、−Ｏ−、−ＣＯＯ−、−ＮＨＣＯ−、−ＮＨ−より選ばれる結合基、Ｙは単結合、又は、非置換またはフッ素原子によって置換されている炭素数１〜２０のアルキレン基を表す。）

(X is a single bond or a linking group selected from —O—, —COO—, —NHCO—, and —NH—, Y is a single bond, unsubstituted or substituted with a fluorine atom, Represents 20 alkylene groups.)

  The diamine having a photopolymerizable side chain containing at least one selected from the methacryl group, acryl group, vinyl group, allyl group, styryl group and α-methylene-γ-butyrolactone group is a liquid crystal alignment film. Depending on the liquid crystal orientation, sensitivity to light, pretilt angle, voltage holding characteristics, accumulated charge characteristics, liquid crystal display response speed, etc. You can also.

  In addition, a diamine having a photopolymerizable side chain containing at least one selected from a methacryl group, an acrylic group, a vinyl group, an allyl group, a styryl group, and an α-methylene-γ-butyrolactone group is a polyamic acid. It is preferable to use an amount that is 10 to 70 mol% of the total amount of diamine components used in the synthesis, more preferably 20 to 60 mol%, and particularly preferably 30 to 50 mol%.

<Diamine having photoreactive group>
When the liquid crystal aligning agent is used in a horizontal alignment type liquid crystal display device produced by irradiating polarized ultraviolet rays, a photoreactive group is introduced into the diamine component that is a raw material of the polyimide precursor contained in the liquid crystal aligning agent. It is preferable that

  In the case of using an alignment treatment method in which photodimerization reaction or photoisomerization reaction proceeds by irradiation with polarized ultraviolet rays and anisotropy is generated, the structure of the above formulas [4-1] to [4-5] It may be introduced into the main chain or side chain.

  When using a polyimide precursor and a polyimide obtained by imidizing it as a polymer to be contained in the liquid crystal aligning agent, the structure of the above formulas [4-1] to [4-5] is contained in the main chain or the side chain. Although there is a method using tetracarboxylic dianhydride or diamine, it is preferable to use a diamine containing the structure of the above formulas [4-1] to [4-5] in the side chain from the viewpoint of ease of synthesis. . The side chain of diamine is a structure branched from a structure connecting two amino groups of diamine. Specific examples of such diamines include, but are not limited to, compounds represented by the following formula.

（式中、Ｘは単結合、又は、−Ｏ−、−ＣＯＯ−、−ＮＨＣＯ−、−ＮＨ−より選ばれる結合基、Ｙは単結合、又は、非置換またはフッ素原子によって置換されている炭素数１〜２０のアルキレン基を表す。Ｒは水素原子、又は、非置換またはフッ素原子によって置換されている炭素数１〜５のアルキル基、もしくはアルキルエーテル基を表す。）

(In the formula, X is a single bond or a linking group selected from —O—, —COO—, —NHCO—, and —NH—, Y is a single bond, or carbon that is unsubstituted or substituted by a fluorine atom. Represents an alkylene group having a number of 1 to 20. R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms which is unsubstituted or substituted by a fluorine atom, or an alkyl ether group.

（式中、Ｘは単結合、又は、−Ｏ−、−ＣＯＯ−、−ＮＨＣＯ−、−ＮＨ−より選ばれる結合基、Ｙは単結合、又は、非置換またはフッ素原子によって置換されている炭素数１〜２０のアルキレン基を表す。Ｒは水素原子、又は、非置換またはフッ素原子によって置換されている炭素数１〜５のアルキル基、もしくはアルキルエーテル基を表す。）

(In the formula, X is a single bond or a linking group selected from —O—, —COO—, —NHCO—, and —NH—, Y is a single bond, or carbon that is unsubstituted or substituted by a fluorine atom. Represents an alkylene group having a number of 1 to 20. R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms which is unsubstituted or substituted by a fluorine atom, or an alkyl ether group.

<Tetracarboxylic dianhydride>
The tetracarboxylic dianhydride that is reacted with the diamine component to obtain a polyamic acid that is a polyimide precursor contained in the liquid crystal aligning agent 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.

  Furthermore, when an aromatic tetracarboxylic dianhydride is used in addition to the tetracyclic dianhydride having the alicyclic structure or aliphatic structure, the liquid crystal alignment is improved and the accumulated charge of the liquid crystal cell is reduced. Since it can reduce, it is preferable. 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.

  Tetracarboxylic dianhydride can be used singly or in combination of two or more according to properties such as liquid crystal orientation, sensitivity to light, pretilt angle, voltage holding characteristics, accumulated charge, etc. when a liquid crystal alignment film is formed.

  The tetracarboxylic acid dialkyl ester that is reacted with the diamine component in order to obtain a polyamic acid ester that is a polyimide precursor contained in the liquid crystal aligning agent is not particularly limited. Specific examples are given below.

Specific examples of the aliphatic tetracarboxylic acid diester include 1,2,3,4-cyclobutanetetracarboxylic acid dialkyl ester, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dialkyl ester, 1 , 3-Dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dialkyl ester, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid dialkyl ester, 1,2, 3,4-cyclopentanetetracarboxylic acid dialkyl ester, 2,3,4,5-tetrahydrofurantetracarboxylic acid dialkyl ester, 1,2,4,5-cyclohexanetetracarboxylic acid dialkyl ester, 3,4-dicarboxy-1 -Cyclohexyl succinic acid dialkyl ester, 3,4-dicarboxy- , 2,3,4-Tetrahydro-1-naphthalene succinic acid dialkyl ester, 1,2,3,4-butanetetracarboxylic acid dialkyl ester, bicyclo [3,3,0] octane-2,4,6,8- Tetracarboxylic acid dialkyl ester, 3,3 ′, 4,4′-dicyclohexyltetracarboxylic acid dialkyl ester, 2,3,5-tricarboxycyclopentylacetic acid dialkyl ester, cis-3,7-dibutylcycloocta-1,5- Diene-1,2,5,6-tetracarboxylic acid dialkyl ester, tricyclo [4.2.1.0 ^2,5 ] nonane-3,4,7,8-tetracarboxylic acid-3, 4: 7,8 A dialkyl ester, hexacyclo [6.6. ^{12, 7} . 0 ^3,6 . 1 ^9,14 . 0 ^10,13] hexadecane -4,5,11,12- tetracarboxylic acid-4,5: 11,12-dialkyl ester, 4- (2,5-di-oxo-tetrahydrofuran-3-yl) -1,2, Examples include 3,4-tetrahydronaphthalene-1,2-dicarboxylic dialkyl ester.

  As the aromatic tetracarboxylic acid dialkyl ester, pyromellitic acid dialkyl ester, 3,3 ′, 4,4′-biphenyltetracarboxylic acid dialkyl ester, 2,2 ′, 3,3′-biphenyltetracarboxylic acid dialkyl ester, 2,3,3 ′, 4-biphenyltetracarboxylic acid dialkyl ester, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid dialkyl ester, 2,3,3 ′, 4-benzophenone tetracarboxylic acid dialkyl ester, bis (3,4-dicarboxyphenyl) ether dialkyl ester, bis (3,4-dicarboxyphenyl) sulfone dialkyl ester, 1,2,5,6-naphthalene tetracarboxylic acid dialkyl ester, 2,3,6,7- Naphthalene tetracarboxylic acid dialkyl ester And the like.

<Polysiloxane>
When the polymer contained in the liquid crystal aligning agent contains polysiloxane, the polysiloxane can be obtained by reacting an alkoxysilane component in an organic solvent (for example, polycondensation reaction). The alkoxysilane component refers to an alkoxysilane having 1 to 4 alkoxy groups in the molecule. For example, polysiloxane can be obtained by reacting an alkoxysilane component represented by the following formula [14].

In the formula [14], R ¹¹ represents a monovalent organic group, and R ¹² is alkyl having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms. More preferably, R ¹² is a methyl group or an ethyl group.

<Alkoxysilane having a vertical alignment side chain>
The alkoxysilane having a side chain to align the liquid crystal vertically, Equation [14] in the alkyl group for R ¹¹ is a long chain, groups having a middle ring structure or branched structure of the long-chain alkyl group, such as a steroid group Examples include hydrocarbon silanes and alkoxysilanes having groups in which some or all of the hydrogen atoms in these groups are replaced by fluorine atoms as side chains, such as diamines having side chains represented by the above formula [5]. it can. More specifically, for example, a diamine having a hydrocarbon group having 8 to 30 carbon atoms in which a hydrogen atom may be substituted with fluorine, or an alkoxysilane represented by the following formula [15] can be given. However, the present invention is not limited to this.

（式［１５］中のａ、ｂ、ｃ、Ｒ^１〜Ｒ^５の定義は、上記式［５］と同じである。式［１５］中、Ｒ^９は単結合もしくは−（ＣＨ_２）_ｎ１Ｏ−（ｎ１は炭素原子数０〜５のアルキル基）、Ｒ^１２は炭素数１〜５、好ましくは１〜３のアルキルを表す。

(The definitions of a, b, c, and R ^{1 to} R ⁵ in Formula [15] are the same as those in Formula [5]. In Formula [15], R ⁹ is a single bond or — (CH ₂ ) _n1. O- (n1 is an alkyl group having 0 to 5 carbon atoms), R ¹² represents an alkyl having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms.

Here, specific examples of the alkoxysilane having a vertical alignment side chain structure represented by the formula [14] are listed below, but the formulas [14-1] to [14-13] are limited thereto. is not. Incidentally, ^{R 12} in the formula [14-1] - [14-13] is the same as ^{R 12} in the formula [14], R ⁹ is the same as R ⁹ in the formula [15].

（式［１４−７］〜式［１４−９］中、Ｒ^１３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またはフッ素含有アルコキシ基である。）

(In the formulas [14-7] to [14-9], R ¹³ represents an alkyl group having 1 to 22 carbon atoms, an alkoxy group, a fluorine-containing alkyl group, or a fluorine-containing alkoxy group.)

（式［１４−１０］および式［１４−１１］中、Ｒ^１４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、アセトキシ基または水酸基である。）

(In the formulas [14-10] and [14-11], R ¹⁴ represents 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.)

（式［１４−１２］および式［１４−１３］中、Ｒ^１５は炭素数３〜１２のアルキル基であり、１，４−シクロヘキシレンのシス−トランス異性は、それぞれトランス異性体である。）

(In the formulas [14-12] and [14-13], R ¹⁵ is an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomerism of 1,4-cyclohexylene is a trans isomer. )

  The alkoxysilane represented by the formula [14] is soluble in a solvent when used as a siloxane polymer (polysiloxane), liquid crystal alignment when used as a liquid crystal alignment film, sensitivity to light, pretilt angle, voltage holding characteristics, One type or a mixture of two or more types can also be used depending on characteristics such as accumulated charge and the response speed of liquid crystal when a liquid crystal display element is used. Moreover, combined use with the alkoxysilane containing a C10-C18 long-chain alkyl group is also possible.

  Thus, the alkoxysilane represented by the formula [14] can be produced by a known method as described in, for example, JP-A No. 61-286393.

<Alkoxysilane having a photopolymerizable side chain>
Moreover, as an alkoxysilane component used for obtaining polysiloxane, for example, an alkoxysilane having a photopolymerizable group represented by the following formula [16] can also be used.

In the formula [16], R ²¹ is an alkyl group in which a hydrogen atom is substituted with an acryl group, an acryloxy group, a methacryl group, a methacryloxy group, or a styryl group. The number of substituted hydrogen atoms is one or more, preferably one. 1-30 are preferable and, as for carbon number of an alkyl group, More preferably, it is 1-20. More preferably, it is 1-10. R ²² is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and particularly preferably 1 to 2 carbon atoms.

  Although the specific example of the alkoxysilane represented by Formula [16] is given, it is not limited to these. For example, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, methacryloxymethyltrimethoxysilane, methacryloxymethyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxy Silane, acryloxyethyltrimethoxysilane, acryloxyethyltriethoxysilane, styrylethyltrimethoxysilane, styrylethyltriethoxysilane, and 3- (N-styrylmethyl-2-aminoethylamino) propyltrimethoxysilane.

<Other alkoxysilanes>
Furthermore, as an alkoxysilane component used for obtaining polysiloxane, for example, an alkoxysilane represented by the following formula [17] can also be used.

R ²³ of the alkoxysilane represented by the formula [17] may be a hydrogen atom, or the hydrogen atom may be substituted with a hetero atom, a halogen atom, an amino group, a glycidoxy group, a mercapto group, an isocyanate group, or a ureido group. It is a C1-C10 hydrocarbon group, Preferably they are an amino group, a glycid group, and a ureido group. R ²⁴ represents an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and n2 represents an integer of 0 to 3, preferably 0 to 2.

  Although the specific example of the alkoxysilane represented by such a formula [17] is given, it is not limited to this. For example, 3- (2-aminoethylaminopropyl) trimethoxysilane, 3- (2-aminoethylaminopropyl) triethoxysilane, 2-aminoethylaminomethyltrimethoxysilane, 2- (2-aminoethylthioethyl) Triethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, vinyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, trifluoropropyltrimethoxysilane, chloropropyltriethoxysilane, bromopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, diethyldimethoxysilane, diphenyldimethoxysilane, diphenyl Diethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyldimethylethoxysilane, trimethylethoxysilane, trimethylmethoxysilane, γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane and γ-ureidopropyltri And propoxysilane.

  In the alkoxysilane represented by the formula [17], the alkoxysilane in which n2 is 0 is tetraalkoxysilane. Tetraalkoxysilane is preferable for obtaining polysiloxane because it easily undergoes a polycondensation reaction with the alkoxysilane represented by the above formulas [14] to [16].

  As such alkoxysilane whose n2 is 0 in the formula [17], tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane or tetrabutoxysilane is more preferable, and tetramethoxysilane or tetraethoxysilane is particularly preferable.

  The method for obtaining the polysiloxane contained in the liquid crystal aligning agent is not particularly limited. For example, the alkoxysilane component containing the alkoxysilane represented by the above formula [14] to formula [17] is reacted in an organic solvent (for example, (Polycondensation reaction). Usually, polysiloxane is obtained as a solution in which such an alkoxysilane component is polycondensed and uniformly dissolved in an organic solvent. In addition, the mixing | blending ratio of the alkoxysilane in the alkoxysilane component containing alkoxysilanes, such as said Formula [14]-[17], is not specifically limited.

  As a method of polycondensation of alkoxysilane to obtain polysiloxane, for example, a method of hydrolyzing and condensing alkoxysilane in an organic solvent such as alcohol or glycol can be mentioned. At that time, the hydrolysis / condensation reaction may be either partial hydrolysis or complete hydrolysis.

  When the liquid crystal aligning agent is used in a vertical alignment type liquid crystal display element, the polysiloxane described above has a group for vertically aligning liquid crystals in the side chain and further has a photopolymerizable group in the side chain. May be. Moreover, when a liquid crystal aligning agent is used for the liquid crystal display element of a horizontal alignment system, you may have a photoreactive group. For this reason, it is preferable that the alkoxysilane component which is a monomer has a group or photopolymerizable group for vertically aligning the liquid crystal introduced in the side chain and a photoreactive group introduced in the main chain or side chain. Such a polysiloxane having a group for vertically aligning a liquid crystal, a photopolymerizable group or a photoreactive group is useful as a polymer for obtaining a liquid crystal alignment film exhibiting the ability to fix the alignment of liquid crystals.

<Poly (meth) acrylate>
When the polymer contained in the liquid crystal aligning agent contains poly (meth) acrylate, the poly (meth) acrylate is caused to undergo a polymerization reaction between a monomer such as an acrylic ester compound or a methacrylic ester compound and a polymerization initiator. Is obtained.

  Examples of the acrylate compound include methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthryl acrylate, anthryl methyl acrylate, phenyl acrylate, 2,2,2-trifluoroethyl acrylate, and tert-butyl. Acrylate, cyclohexyl acrylate, isobornyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, 2-methyl-2-adamantyl acrylate, 2- Propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecyl acrylate and Such as 8-ethyl-8-tricyclodecyl acrylate.

  Examples of the methacrylic acid ester compound include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methacrylate, anthryl methyl methacrylate, phenyl methacrylate, 2,2,2-trifluoroethyl methacrylate, tert-butyl. Methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 3-methoxybutyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2- Propyl-2-adamantyl methacrylate, 8-methyl 8 tricyclodecylacrylate methacrylate and 8-ethyl-8-tricyclodecyl methacrylate, and the like.

  When the liquid crystal aligning agent is used in a vertical alignment type liquid crystal display element, the poly (meth) acrylate described above has a group for vertically aligning liquid crystals in the side chain, and further has a photopolymerizable group in the side chain. You may have. Moreover, when a liquid crystal aligning agent is used for the liquid crystal display element of a horizontal alignment system, poly (meth) acrylate may have a photoreactive group. For this reason, acrylic acid ester compounds and methacrylic acid ester compounds, which are monomers, have a group or photopolymerizable group for vertically aligning liquid crystals introduced into the side chain and a photoreactive group introduced into the main chain or side chain. It is preferable. Such a poly (meth) acrylate having a group for vertically aligning a liquid crystal, a photopolymerizable group or a photoreactive group is useful as a polymer for obtaining a liquid crystal alignment film exhibiting the ability to fix the alignment of liquid crystals. is there.

  Here, examples of the acrylate compound having a side chain and the methacrylic acid ester compound include an acrylate compound having a side chain represented by the above formula [5] and a methacrylic acid ester compound. . More specifically, for example, acrylic ester compounds and methacrylic ester compounds represented by the following formula [18] and the following formulas [19-1] to [19-3] can be exemplified, but the present invention is not limited thereto. Is not to be done.

（式［１８］中のａ、ｂ、ｃ、Ｒ^１〜Ｒ^５の定義は、上記式［５］と同じである。Ｒは水素原子もしくはメチル基、Ｓは炭素原子数２〜１１のアルキレン基である。）

(The definitions of a, b, c, and R ^{1 to} R ⁵ in Formula [18] are the same as those in Formula [5]. R is a hydrogen atom or a methyl group, and S is an alkylene having 2 to 11 carbon atoms. Group.)

（Ｒは水素原子もしくはメチル基、Ｓは炭素原子数２〜１１のアルキレン基、Ｘはエーテル、エステル、アミド結合、Ｒ^１０は水素原子、または非置換またはフッ素原子によって置換されている炭素数１〜５のアルキル基である。）

(R is a hydrogen atom or a methyl group, S is an alkylene group having 2 to 11 carbon atoms, X is an ether, ester or amide bond, R ¹⁰ is a hydrogen atom, or an unsubstituted or substituted carbon atom having 1 carbon atom. ˜5 alkyl groups.)

<Solvent>
The solvent which a liquid crystal aligning agent contains will not be specifically limited if the said polymer is melt | dissolved uniformly. Moreover, when a liquid crystal aligning agent contains the said polymeric compound, if a polymer and a polymeric compound are melt | dissolved uniformly, it will not specifically limit. Specific examples thereof include N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone when a polyimide precursor or polyimide is used as the polymer. N-ethyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl sulfoxide, dimethyl sulfone, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, 3-methoxy-N , N-dimethylpropanamide and the like. When polysiloxane is used as the polymer, examples thereof include polyhydric alcohol compounds such as ethylene glycol and 1,2-propylene glycol, amide compounds such as N-methylformamide and N, N-dimethylformamide, and the like. Can do. Moreover, when using poly (meth) acrylate as a polymer, an alcohol compound, a ketone compound, an amide compound, an ester compound, or another aprotic compound can be mentioned, for example. You may use these 1 type or in mixture of 2 or more types. Moreover, even if it is a solvent which cannot melt | dissolve a polymer and a polymeric compound uniformly by itself, as long as a polymer and a polymeric compound do not precipitate, you may mix with said organic solvent.

  A liquid crystal aligning agent may contain the solvent for improving the coating-film uniformity at the time of apply | coating a liquid crystal aligning agent to a board | substrate other than the solvent for dissolving a polymer and a polymeric compound. As such a solvent, a solvent having a surface tension lower than that of the organic solvent is generally used. Specific examples thereof include ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2 -Propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, butyl cellosolve acetate, di Propylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl ester, lactic acid Isoamyl ester, and the like. Two types of these solvents may be used in combination.

  In addition to the above, the liquid crystal aligning agent changes the electrical characteristics such as the dielectric constant and conductivity of the polymer other than the above-described polymer and the liquid crystal aligning film as long as the effects of the present invention are not impaired. Target dielectric or conductive material, silane coupling agent for improving adhesion between liquid crystal alignment film and substrate, compound for improving film thickness uniformity and surface smoothness when liquid crystal aligning agent is applied, liquid crystal alignment Add a crosslinkable compound for the purpose of increasing the hardness and density of the film when it is made into a film, and also an imidization accelerator for the purpose of efficiently advancing the imidization of the polyimide precursor when baking the coating film. Also good.

  Examples of compounds that improve film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. More specifically, for example, F-top EF301, EF303, EF352 (manufactured by Tochem Products), MegaFuck F171, F173, R-30 (manufactured by Dainippon Ink), Florard FC430, FC431 (manufactured by Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.). When using these surfactants, the use ratio is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 2 parts by mass with respect to 100 parts by mass of the total amount of the polymer contained in the liquid crystal aligning agent. 1 part by mass.

  Specific examples of compounds that improve the adhesion between the liquid crystal alignment film and the substrate include 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 ′ , N′-tetraglycidyl-4, 4′-diaminodiphenylmethane, 3- (N-allyl-N-glycidyl) aminopropyltrimethoxysilane, 3- (N, N-diglycidyl) aminopropyltrimethoxysilane and the like. . In order to further increase the film strength of the liquid crystal alignment film, a phenol compound such as 2,2'-bis (4-hydroxy-3,5-dihydroxymethylphenyl) propane or tetra (methoxymethyl) bisphenol may be added. When using these compounds, it is preferable that it is 0.1-30 mass parts with respect to 100 mass parts of total amounts of the polymer contained in a liquid crystal aligning agent, More preferably, it is 1-20 mass parts.

<Liquid crystal alignment film>
The liquid crystal alignment film used for the liquid crystal display element of the present invention is obtained by applying the liquid crystal aligning agent to a substrate, drying it as necessary, and then performing an alignment treatment on the coating surface obtained by baking. .

  The substrate on which the liquid crystal aligning agent is applied is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, a silicon nitride substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, and the like can be used. Use of a substrate on which an ITO (Indium Tin Oxide) electrode or the like is formed is preferable from the viewpoint of simplification of the process. In the reflective liquid crystal display element, an opaque object such as a silicon wafer can be used as long as only one substrate is used. In this case, a material that reflects light, such as aluminum, can be used.

  A method for applying the liquid crystal aligning agent is not particularly limited, but industrially, a method of performing screen printing, offset printing, touch basic printing, an inkjet method, or the like is common. Other coating methods include a dipping method, a roll coater method, a slit coater method, a spinner method, and a spray method, and these may be used depending on the purpose.

  After the liquid crystal aligning agent is applied on the substrate, it is 30 to 300 ° C., preferably 30 depending on the solvent used for the liquid crystal aligning agent by a heating means such as a hot plate, a thermal circulation oven or an IR (infrared) oven. The solvent can be evaporated at a temperature of ˜250 ° C. to obtain a liquid crystal alignment film. If the thickness of the liquid crystal alignment film after baking is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may be lowered. Is 10 to 100 nm.

<Orientation treatment>
In a liquid crystal display element of a horizontal alignment method such as an IPS method or an FFS method, an alignment process by a so-called photo-alignment method is performed in the manufacturing process by irradiating the liquid crystal layer and the liquid crystal alignment film with polarized ultraviolet rays. In a vertical alignment type liquid crystal display element such as a VA type, an alignment process is performed by applying an electric field to a liquid crystal layer and a liquid crystal alignment film and irradiating ultraviolet rays in a state where the liquid crystal is tilted. Such alignment process by the photo-alignment method and the vertical alignment application can fix the alignment direction of the liquid crystal without performing the rubbing process.

  In the present invention, not only the polymer in the liquid crystal alignment film is reacted by irradiation with polarized ultraviolet rays or ultraviolet rays, but also the polymerizable compound contained in the liquid crystal layer described above is photopolymerized or photocrosslinked. The direction is fixed more reliably.

As a preferred specific example of the alignment treatment by the photo-alignment method, the coating film surface is irradiated with polarized ultraviolet rays in a certain direction including ultraviolet rays having a wavelength of 200 nm to 400 nm, preferably 210 nm to 380 nm, for example, 300 nm to 350 nm, Depending on the case, the method of performing the heat processing at the temperature of 150-250 degreeC further, and providing the orientation fixing ability of a liquid crystal is mentioned. Moreover, in order to improve the orientation fixing ability, the coated substrate may be irradiated with ultraviolet rays while being heated at 50 to 250 ° C. Irradiation amount of the ultraviolet rays, preferably in the range of 1~10,000mJ / cm ^2, and particularly preferably in the range of 1~2,000mJ / cm ^2.

  Further, the film irradiated with polarized ultraviolet rays may be contact-treated with water or a solution containing a specific organic solvent. The organic solvent is not particularly limited, but water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, lactic acid Examples include methyl, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, and cyclohexyl acetate. Among the above solvents, since a liquid crystal alignment film having high anisotropy and no unevenness is easily obtained, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate And at least one selected from the group consisting of diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, and cyclohexyl acetate. In particular, at least one selected from the group consisting of 1-methoxy-2-propanol and ethyl lactate is preferable.

  The contact treatment between the film irradiated with polarized ultraviolet rays and the solution containing the organic solvent is preferably performed by a treatment such that the film and the liquid are sufficiently in contact with each other, such as an immersion treatment or a spray treatment. Especially, the method of immersing a film | membrane in the solution containing an organic solvent, Preferably it is 10 second-1 hour, More preferably, 1 minute-30 minutes is preferable. The contact treatment may be performed at normal temperature or preferably at 10 to 80 ° C., more preferably at 20 to 50 ° C. Moreover, a means for enhancing contact such as ultrasonic waves can be applied as necessary.

  After the above contact treatment, for the purpose of removing the organic solvent in the used solution, either rinsing with water or a low boiling point solvent such as methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, or drying, or both May be done. As temperature in the case of drying, 80-250 degreeC is preferable and 80-150 degreeC is more preferable.

  The liquid crystal alignment film obtained as described above can stably align liquid crystals in a certain direction.

<Method for Manufacturing Liquid Crystal Display Element for Driving Horizontal Electric Field>
As a liquid crystal display element of the present invention, a horizontal electric field driving liquid crystal display element of a horizontal alignment method such as an IPS method or an FFS method is used for driving a horizontal electric field by a known method after obtaining a substrate with the above liquid crystal alignment film. A liquid crystal cell is manufactured, and a liquid crystal display element for driving a horizontal electric field is formed using the liquid crystal cell. Note that the horizontal electric field driving type liquid crystal display element is a type of liquid crystal display element that switches liquid crystal molecules by applying an electric field in a horizontal direction (lateral direction) with respect to a substrate.

  As an example of a method for manufacturing a liquid crystal display element for driving a horizontal electric field, a liquid crystal display element having a passive matrix structure will be described as an example. In addition, a liquid crystal display element for driving a horizontal electric field having an active matrix structure in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting an image display.

  The substrate used for the horizontal electric field driving liquid crystal display element is not particularly limited as long as it is a highly transparent substrate, but is usually a substrate on which a transparent electrode for driving liquid crystal is formed. Specific examples thereof include the same substrates as those described in the above <Liquid crystal alignment film>.

  In addition, the liquid crystal alignment film is formed by applying the liquid crystal alignment agent on the substrate and then baking, and irradiating with radiation such as rubbing treatment or polarized ultraviolet rays as necessary. Next, the other substrate is overlaid on one substrate so that the liquid crystal alignment film faces each other, and the periphery is bonded with a sealant. In order to control the substrate gap, a spacer is usually mixed in the sealing material. In addition, it is preferable to spray spacers for controlling the substrate gap on the in-plane portion where no sealing material is provided. A part of the sealing material is provided with an opening that can be filled with liquid crystal from the outside.

  Next, a liquid crystal layer containing a liquid crystal and a polymerizable compound is injected into a space surrounded by the two substrates and the sealing material through an opening provided in the sealing material to form a liquid crystal layer. Although the liquid crystal contained in a liquid-crystal composition is not specifically limited, For example, liquid crystal MLC-2041 (made by Merck Ltd.) etc. can be used. As the polymerizable compound, for example, compounds represented by the above formulas [1-1] to [1-4] and the above formulas [2-1] to [2-3] can be used. In addition, you may contain a polymeric compound in a liquid crystal aligning agent.

  Thereafter, the opening is sealed with an adhesive. For the injection, a vacuum injection method may be used, or a method utilizing capillary action in the atmosphere may be used. Thereby, a liquid crystal cell for driving a horizontal electric field is created.

  Next, the liquid crystal cell for driving the transverse electric field is irradiated with light such as ultraviolet rays. Here, the irradiation amount of ultraviolet rays is, for example, 1 to 60 J, preferably 40 J or less, and the smaller the irradiation amount of ultraviolet rays, the lowering of reliability caused by the destruction of the members constituting the liquid crystal display element can be suppressed, and the irradiation with ultraviolet rays is performed. It is preferable because manufacturing efficiency is increased by reducing the time. The wavelength of the irradiated ultraviolet light is, for example, 200 nm to 400 nm.

  In this way, when the liquid crystal cell is irradiated with light such as ultraviolet rays, that is, when the liquid crystal layer or the liquid crystal alignment film is irradiated with light such as ultraviolet rays, the polymerizable unsaturated bond group or the liquid crystal alignment that the polymerizable compound in the liquid crystal layer has. The photoreactive group of the polymer in the film reacts to fix the alignment of the liquid crystal in the liquid crystal layer and the liquid crystal positioned on the surface of the liquid crystal alignment film. Next, a polarizing plate is installed. Specifically, a pair of polarizing plates is attached to the surfaces of the two substrates opposite to the liquid crystal layer. Through the above steps, a lateral electric field driving liquid crystal display element is obtained.

<Method for Manufacturing Liquid Crystal Display Element for Driving Vertical Electric Field>
As a liquid crystal display element of the present invention, a vertical electric field driving liquid crystal display element of a vertical alignment system such as a VA system is obtained by obtaining a substrate with the above-mentioned liquid crystal alignment film and then manufacturing a liquid crystal cell by a known method. Can do. Specifically, a liquid crystal alignment film is formed by applying and baking a liquid crystal alignment agent on two substrates, and the two substrates are arranged so that the liquid crystal alignment films face each other. A liquid crystal composition containing a liquid crystal and a polymerizable compound is injected between the substrates to form a liquid crystal layer. Then, by irradiating ultraviolet rays while applying a voltage to the liquid crystal layer and the liquid crystal alignment film, a vertical alignment type liquid crystal display element for vertical electric field driving having a liquid crystal cell is obtained.

  Examples of the substrate used for the vertical electric field driving liquid crystal display element include the same substrates as those described in the above <Liquid crystal alignment film>. Further, a substrate provided with a conventional electrode pattern or protrusion pattern may be used. As a high-performance element such as a TFT element, an element in which an element such as a transistor is formed between an electrode for driving a liquid crystal and a substrate is used. About the formation method of a liquid crystal aligning film and a liquid-crystal layer, it is the same as that of the case of said liquid crystal display element for a horizontal electric field drive.

In the step of irradiating ultraviolet rays while applying a voltage, for example, a voltage is applied between the electrodes installed on the substrate to apply a voltage to the liquid crystal layer and the liquid crystal alignment film, and the ultraviolet rays are irradiated while maintaining this voltage. A method is mentioned. Here, a function generator can be used as means for applying a voltage, and an existing apparatus such as a high-pressure mercury lamp can be used as means for irradiating ultraviolet rays. The voltage applied between the electrodes is, for example, 5 to 30 Vp-p, preferably 5 to 20 Vp-p. The wavelength of the ultraviolet light is preferably 250 to 400 nm, more preferably 300 to 400 nm. The irradiation amount of ultraviolet rays is, for example, 1 to 60 J / cm ² , preferably 40 J / cm ² or less, and the smaller the ultraviolet irradiation amount, the lowering of reliability due to the destruction of the members constituting the liquid crystal display can be suppressed, and the ultraviolet rays can be suppressed. It is preferable because the production efficiency is increased by reducing the irradiation time.

  A polymerizable unsaturated bond group possessed by the polymerizable compound in the liquid crystal layer, a group that vertically aligns the liquid crystal possessed by the polymer in the liquid crystal alignment film, or a photopolymerizable group by irradiating ultraviolet rays while applying voltage. Causes a reaction, and the direction in which the liquid crystal in the liquid crystal layer and the liquid crystal positioned on the surface of the liquid crystal alignment film tilt is stored.

  The liquid crystal display elements for lateral electric field driving and vertical electric field driving manufactured by the method for manufacturing a liquid crystal display element of the present invention described above include a liquid crystal layer containing a polymerizable compound. Such a polymerizable compound has a highly polar group such as a carboxyl group or a hydroxyl group, that is, a functional group capable of hydrogen bonding, thereby improving the solubility in liquid crystal. Thereby, the unreacted polymerizable compound does not remain as an impurity, and the sensitivity of the liquid crystal layer to light increases. In addition, the polymerizable compound has an aromatic ring in the vicinity of the functional group that forms a hydrogen bond, and forms a pseudo mesogen structure in the liquid crystal composition or in the liquid crystal layer together with the functional group that forms a hydrogen bond. As a result, as shown in the examples to be described later, the sensitivity to high-wavelength ultraviolet irradiation is high, the orientation can be fixed even with low-energy ultraviolet irradiation, the response speed is fast, and the afterimage generation is suppressed. A liquid crystal display element is realized. Such a liquid crystal display element can be suitably used for a large-screen and high-definition liquid crystal television.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples.

<Synthesis of polymerizable compound>
Abbreviations of the polymerizable compounds contained in the liquid crystal composition in the present invention are as follows. The polymerizable compounds [RM1] to [RM3] are the same as the polymerizable compounds of the above formulas [2-1] to [2-3].

<Synthesis Example 1>
A known polymerizable compound represented by the following formula was designated as a polymerizable compound [RM1].

<Synthesis Example 2>
Synthesis of polymerizable compound [RM2]

  In a 2 L four-necked flask, 6-bromo-2-naphthol [H] (150 g, 672 mol), tert-butyl acrylate [B] (103.4 g, 807 mmol), palladium acetate (3.02 g, 13.5 mmol) , Tri (o-tolyl) phosphine (8.19 g, 26.9 mmol), tripropylamine (289.0 g, 2.02 mol) and DMAc (700 g) were added, and the mixture was heated and stirred at 100 ° C. The reaction was traced by HPLC, and after confirming the completion of the reaction, the reaction solution was cooled to around room temperature and poured into 3 L of 1M aqueous hydrochloric acid. Ethyl acetate (2 L) was added thereto, and the aqueous layer was removed by a liquid separation operation. The organic layer was washed twice with 1 L of a 10% aqueous hydrochloric acid solution and three times with 1 L of saturated brine, and then dried over magnesium sulfate. Then, 181g of compound [I] was obtained by filtering and distilling a solvent off by the evaporator (yield 99%).

The measurement result of the nuclear magnetic resonance (NMR) of the compound [I] was as follows.
¹ H-NMR (400 MHz, DMSO-d6, δ ppm): 10.1 (1H, s), 8.04 (1H, s), 7.81-7.74 (2H, m), 7.70-7 63 (2H, m), 7.14-7.10 (2H, m), 6.54 (1H, d), 1.51-1.48 (9H, m).

  The compound [I] obtained above (181 g, 672 mmol), 6-chloro-1-hexanol (110.2 g, 806 mol), potassium carbonate (111.5 g, 806 mmol), potassium iodide (1.12 g, 6.7 mmol), and DMF (900 g) were added, and the mixture was heated and stirred at 80 ° C. Reaction tracking was performed by HPLC, and after confirming the completion of the reaction, 2 L of distilled water was poured into the reaction solution, ethyl acetate (2 L) was added, and the aqueous layer was removed by a liquid separation operation. Thereafter, the organic layer was washed twice with saturated brine (1 L), the organic layer was dried over magnesium sulfate, filtered, and then the solvent was distilled off to obtain a crude product. The obtained crude product was recrystallized with a mixed solvent of ethyl acetate / hexane to obtain 185 g of Compound [J] (yield 74%).

The measurement result of the nuclear magnetic resonance (NMR) of the compound [J] was as follows.
¹ H-NMR (400 MHz, DMSO-d6, δ ppm): 8.06 (1H, s), 7.80 (1H, d), 7.77-7.76 (2H, m), 7.62 (1H , D), 7.34 (1H, d), 7.15 (1H, dd), 6.53 (1H, d), 4.34 (1H, t), 4.05 (2H, t), 3 39-3.33 (2H, m), 1.73 (2H, t), 1.46-1.31 (15H, m).

  The compound [J] obtained above (130.5 g, 352 mmol), triethylamine (42.76 g, 423 mmol), and THF (950 g) were added to a 3 L four-necked flask, and the reaction solution was cooled. A solution of methacrylic acid chloride (44.2 g, 423 mmol) in THF (100 g) was added dropwise thereto with care so that the internal temperature did not exceed 10 ° C. After completion of the dropwise addition, the reaction solution was brought to 23 ° C. for further reaction. Reaction tracking was performed by HPLC, and after confirming the completion of the reaction, 6 L of distilled water was poured into the reaction solution, 2 L of ethyl acetate was added, and the aqueous layer was removed by a liquid separation operation. Thereafter, the organic layer was washed successively with 5% aqueous potassium hydroxide solution, 1M aqueous hydrochloric acid solution and saturated brine, and the organic layer was dried over magnesium sulfate. Thereafter, filtration and evaporation of the solvent with an evaporator gave 140.9 g of Compound [K] (yield 92%).

The measurement result of the nuclear magnetic resonance (NMR) of the compound [K] was as follows.
¹ H-NMR (400 MHz, DMSO-d6, δ ppm): 8.09 (1H, s), 7.83 (1H, d), 7.80-7.79 (2H, m), 7.66 (1H , D), 7.33 (1H, d), 7.18 (1H, dd), 6.57 (1H, d), 6.02-6.01 (1H, m), 5.66-5. 65 (1H, m), 4.12-4.06 (4H, m), 1.88-1.87 (3H, m), 1.84-1.42 (15H, m).

  The compound [K] obtained above (140.9 g, 321 mmol) and formic acid (700 g) were added to a 3 L four-necked flask, and the mixture was heated and stirred at 40 ° C. Reaction tracking was performed by HPLC, and after confirming the completion of the reaction, 4.5 L of distilled water was poured into the reaction solution and filtered. The obtained solid was washed with an IPA / hexane mixed solvent, and the solid was dried to obtain 95.9 g of a polymerizable compound [RM2] (yield 78%).

The measurement result of the nuclear magnetic resonance (NMR) of the polymerizable compound [RM2] was as follows.
¹ H-NMR (400 MHz, DMSO-d6, δ ppm): 12.4 (1H, brs), 8.10 (1H, s), 7.84 (1H, d), 7.81-7.80 (2H , M), 7.70 (1H, d), 7.35 (1H, d), 7.19 (1H, dd), 6.59 (1H, d), 6.03-6.02 (1H, m), 5.67-5.65 (1H, m), 4.13-4.07 (4H, m), 1.88-1.87 (3H, m), 1.83-1.41 ( 8H, m).

<Synthesis Example 3>
Synthesis of polymerizable compound [RM3]

  The same operation as in Example 1 was performed except that 6-chloro-1-hexanol used in the synthesis of compound [J], which was an intermediate of polymerizable compound [RM2], was changed to 8-chloro-1-hexanol. And 171 g of multi-layer compound [RM3] was obtained.

The measurement result of the nuclear magnetic resonance (NMR) of the polymerizable compound [RM3] was as follows.
¹ H-NMR (400 MHz, CDCl 3, δ ppm): 12.4 (1H, brs), 7.94-7.88 (2H, m), 7.77-7.71 (2H, m), 7.70 -7.63 (1H, m), 7.17 (1H, dd), 7.12-7.11 (1H, m), 6.51 (1H, d), 6.11-6.10 (1H M), 5.55-5.54 (1H, m), 4.17-4.06 (4H, m), 1.95-1.94 (3H, m), 1.87-1.40. (12H, m).

<Comparative Synthesis Example 1>
A known polymerizable compound represented by the following formula was designated as a polymerizable compound [RM4].

<Preparation of liquid crystal composition>
<Preparation Example 1>
0.03 g (0.3 wt%) of a polymerizable compound [RM1] is added to 10.0 g of Merck negative type liquid crystal MLC-6608 (trade name, manufactured by Merck) and added on a 130 ° C. hot plate. The liquid crystal composition (LC1) was prepared by warming and completely dissolving RM1.

<Preparation Example 2>
0.03 g (0.3 wt%) of a polymerizable compound [RM2] is added to 10.0 g of Merck negative type liquid crystal MLC-6608 (trade name, manufactured by Merck), and added on a 130 ° C. hot plate. The liquid crystal composition (LC2) was prepared by warming and completely dissolving RM2.

<Preparation Example 3>
0.03 g (0.3 wt%) of a polymerizable compound [RM3] is added to 10.0 g of Merck negative type liquid crystal MLC-6608 (trade name, manufactured by Merck), and added on a 130 ° C. hot plate. Warm and completely dissolve RM3 to prepare a liquid crystal composition (LC3).

<Comparative Preparation Example 1>
0.03 g (0.3 wt%) of a polymerizable compound [RM4] is added to 10.0 g of Merck negative type liquid crystal MLC-6608 (trade name, manufactured by Merck), and added on a 130 ° C. hot plate. Warm and completely dissolve RM4 to prepare a liquid crystal composition (LC4).

<Preparation Example 4>
0.03 g (0.3 wt%) of the polymerizable compound [RM2] is added to 10.0 g of positive type liquid crystal MLC-2041 (trade name, manufactured by Merck) manufactured by Merck and added on a 130 ° C. hot plate. Warm, RM2 was completely dissolved to prepare a liquid crystal composition (LC5).

<Comparative Preparation Example 2>
0.03 g (0.3 wt%) of a polymerizable compound [RM4] is added to 10.0 g of a positive type liquid crystal MLC-2041 (trade name, manufactured by Merck) manufactured by Merck and added on a hot plate at 130 ° C. Warm and completely dissolve RM4 to prepare a liquid crystal composition (LC6).

<Preparation of liquid crystal aligning agent>
The abbreviations used in the preparation of the liquid crystal aligning agent are as follows.
BODA: bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride DBA: 3.5-diamino Benzoic acid m-PCH7: 1,3-diamino-5-((4- (4-heptylcyclohexyl) phenoxy) methyl) benzene represented by the following formula

PCH7: 1,3-diamino-4- [4- (4-heptylcyclohexyl) phenoxy] benzene represented by the following formula

BEM-S: 2- (methacryloyloxy) ethyl 3,5-diaminobenzoate represented by the following formula

NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve

<Additives>
3AMP: 3-picolylamine

<Liquid crystal aligning agent synthesis example 1>
BODA (10.0 g, 40.0 mmol), DBA (5.3 g, 35.0 mmol), m-PCH7 (12.0 g, 30.0 mmol), BEM-S (9.2 g, 35.0 mmol) were added to NMP ( 144.5 g), and after reacting at 60 ° C. for 5 hours, CBDA (11.5 g, 58.5 mmol) and NMP (48.2 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution. Obtained. After adding NMP to this polyamic acid solution (200 g) and diluting to 6% by mass, acetic anhydride (17.0 g) and pyridine (65.8 g) were added as imidization catalysts, and the mixture was reacted at 50 ° C. for 3 hours. This reaction solution was poured into methanol (3000 ml), and the resulting precipitate was separated by filtration. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 60 degreeC, and obtained the polyimide powder (A1). The imidation ratio of this polyimide was 60%, the number average molecular weight was 14,000, and the weight average molecular weight was 47,000.

  NMP (44.0 g) was added to the obtained polyimide powder (A1) (6.0 g), and the mixture was dissolved by stirring at 50 ° C. for 5 hours. 3AMP (1 wt% NMP solution) 6.0g, NMP (14.0g), and BCS (30.0g) were added to this solution, and the liquid crystal aligning agent (A) was obtained by stirring at room temperature for 5 hours.

<Liquid crystal aligning agent synthesis example 2>
After reacting CBDA (1.92 g, 10.0 mmol) and DA1 (3.97 g, 10.0 mmol) in NMP (23.6 g) at room temperature for 10 hours, NMP (39.3 g), BCS (29. 3g) was added, and the liquid crystal aligning agent (B) was obtained by stirring at room temperature for 5 hours. The number average molecular weight of this polyamic acid was 15,000, and the weight average molecular weight was 61,000.

The conditions for measuring the molecular weight of the polyimide contained in the liquid crystal aligning agents obtained in the liquid crystal aligning agent synthesis examples 1 and 2 are as follows.
Apparatus: Senshu Science Co., Ltd. room temperature gel permeation chromatography (GPC) apparatus (SSC-7200)
Column: Column made by Shodex (KD-803, KD-805)
Column temperature: 50 ° C
Eluent: N, N′-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H ₂ O) is 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) is 30 mmol / L, Tetrahydrofuran (THF) 10ml / L)
Flow rate: 1.0 ml / min. Standard sample for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight of about 9,000,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene manufactured by Polymer Laboratory Glycol (molecular weight about 12,000, 4,000, 1,000).

Moreover, the imidation ratio of polyimide was measured as follows. Add 20 mg of polyimide powder to an NMR sample tube (NMR sampling tube standard φ5 manufactured by Kusano Kagaku Co., Ltd.), add 1.0 ml of deuterated dimethyl sulfoxide (DMSO-d ₆ , 0.05% TMS mixture), and apply ultrasonic waves. To dissolve completely. 500 MHz proton NMR was measured for this solution with the NMR measuring device by the JEOL datum company (JNW-ECA500). The imidation rate is determined based on protons derived from structures that do not change before and after imidation as reference protons, and the peak integrated value of these protons and proton peaks derived from NH groups of amic acid appearing near 9.5 to 10.0 ppm. It calculated | required by the following formula | equation using the integrated value. In the following formula, x is the proton peak integrated value derived from the NH group of the amic acid, y is the peak integrated value of the reference proton, and α is the proton of the NH group of the amic acid in the case of polyamic acid (imidation rate is 0%). This is the ratio of the number of reference protons to one.

  Imidation ratio (%) = (1−α · x / y) × 100

<Preparation of liquid crystal cell for PSA mode>
Example 1
Using the liquid crystal composition (LC1) obtained in Preparation Example 1 and the liquid crystal aligning agent (A) obtained in Liquid Crystal Alignment Agent Synthesis Example 1, a liquid crystal cell was prepared according to the procedure shown below. The liquid crystal aligning agent (A) is spin coated on the ITO surface of the ITO electrode substrate on which an ITO electrode pattern having a pixel size of 100 μm × 300 μm and a line / space of 5 μm is formed, and dried on a hot plate at 80 ° C. for 90 seconds. Then, baking was performed in a hot air circulation oven at 200 ° C. for 30 minutes to form a liquid crystal alignment film having a thickness of 100 nm.

  Moreover, after spin-coating the liquid crystal aligning agent (A) to the ITO surface in which the electrode pattern is not formed, and drying for 90 seconds with an 80 degreeC hotplate, it baked for 30 minutes with a 200 degreeC hot-air circulation type oven, A liquid crystal alignment film having a thickness of 100 nm was formed.

  After spraying a 6 μm bead spacer on the liquid crystal alignment film of one of the two substrates, a sealant (solvent type thermosetting epoxy resin) was printed thereon. Next, the surface of the other substrate on which the liquid crystal alignment film was formed was faced inward and bonded to the previous substrate, and then the sealing agent was cured to produce an empty cell. Into this empty cell, the liquid crystal composition (LC1) obtained in Preparation Example 1 was injected by a reduced pressure injection method to produce a liquid crystal cell.

(Example 2)
A liquid crystal cell was prepared in the same manner as in Example 1 except that the liquid crystal composition (LC2) containing the polymerizable compound [RM2] obtained in Preparation Example 2 was used instead of the liquid crystal composition (LC1). Produced.

(Example 3)
A liquid crystal cell was prepared in the same manner as in Example 1 except that the liquid crystal composition (LC3) containing the polymerizable compound [RM3] obtained in Preparation Example 3 was used instead of the liquid crystal composition (LC1). Produced.

(Example 4)
A liquid crystal cell was produced in the same manner as in Example 1 except that a liquid crystal vertical alignment agent (manufactured by Nissan Chemical Industries, Ltd .: SE-5561) was used instead of the liquid crystal alignment agent (A).

(Comparative Example 1)
A liquid crystal cell was prepared in the same manner as in Example 1, except that the liquid crystal composition (LC4) containing the polymerizable compound [RM4] obtained in Comparative Preparation Example 1 was used instead of the liquid crystal composition (LC1). Was made.

<Measurement of response speed>
The response speeds of the liquid crystal cells obtained in Examples 1 to 4 and Comparative Example 1 were measured by the following method.
First, a liquid crystal cell was arranged between a pair of polarizing plates in a measuring device configured in the order of a backlight, a set of polarizing plates in a crossed Nicol state, and a light amount detector. At this time, the ITO electrode pattern in which the line / space was formed was at an angle of 45 ° with respect to the crossed Nicols. Then, a rectangular wave with a voltage of ± 6 V and a frequency of 1 kHz is applied to the liquid crystal cell, and the change until the luminance observed by the light quantity detector is saturated is captured by an oscilloscope. The luminance when no voltage is applied is obtained. A voltage of 0% and ± 4 V was applied, the saturated luminance value was set to 100%, and the time taken for the luminance to change from 10% to 90% was defined as the response speed.

  After measuring the response speed, 5 J UV irradiation through a 365 nm band-pass filter was performed from the outside of the liquid crystal cell with an AC voltage of ± 10 V applied to the liquid crystal cell. Thereafter, the response speed was measured again, and the response speed before and after UV irradiation was compared.

<Measurement of pretilt angle>
For the liquid crystal cells obtained in Examples 1 to 4 and Comparative Example 1, the pretilt angle of the pixel portion after the UV irradiation was measured. As a measuring device, LCD analyzer LCA-LUV42A manufactured by Meiryo Technica was used.
Table 2 shows the measurement results of response speed and pretilt angle before and after UV irradiation.

  As shown in Table 2, Examples 1 to 4 using a polymerizable compound having a functional group (carboxyl group) that forms a hydrogen bond, that is, a polymerizable compound [RM1] to [RM3] that forms a hydrogen bond between molecules. Compared with the comparative example 1 which used polymeric compound [RM4] which does not have a carboxyl group, the response speed of this liquid crystal cell became very quick. This is because the polymerizable compounds [RM1] to [RM3] have a highly polar carboxyl group, so that the solubility in the liquid crystal is improved, and the carboxyl group and one or more aromatic rings located in the vicinity of the carboxyl group. This is thought to be due to the formation of pseudo mesogenic structures between molecules. The liquid crystal cells of Examples 1 to 4 were sensitive to ultraviolet rays (365 nm) on the long wavelength side due to the formation of this huge mesogen structure, and a sufficiently high response speed was achieved even when irradiated with 365 nm ultraviolet rays. In addition, a good pretilt angle was obtained, and the alignment fixing ability was excellent.

  On the other hand, when the polymerizable compound [RM4] of Comparative Example 1 is used, since the mesogen site has a simple biphenyl structure, there is almost no sensitivity to 365 nm, and a sufficient response speed cannot be obtained by irradiation at 365 nm. It was.

  As a result, a liquid crystal display element containing a polymerizable compound that forms a hydrogen bond between molecules in the liquid crystal layer has high sensitivity to light, has excellent alignment fixability, and can realize a fast response speed. It was.

<Preparation of liquid crystal cell for optical IPS mode>
(Example 5)
Using the liquid crystal composition (LC5) obtained in Synthesis Example 4 and the liquid crystal aligning agent (B) obtained in Synthesis Example 2 of the liquid crystal aligning agent, a liquid crystal cell was prepared according to the procedure shown below. The substrate used was a glass substrate having a size of 30 mm × 40 mm and a thickness of 0.7 mm, on which comb-like pixel electrodes formed by patterning an ITO film were arranged. The pixel electrode has a comb-like shape configured by arranging a plurality of dog-shaped electrode elements whose central portion is bent. The width in the short direction of each electrode element is 10 μm, and the distance between the electrode elements is 20 μm. Since the pixel electrode forming each pixel is formed by arranging a plurality of bent-shaped electrode elements in the central portion, the shape of each pixel is not rectangular, but in the central portion like the electrode elements. It has a shape that bends and resembles a bold-faced koji. Each pixel is divided into upper and lower portions with a central bent portion as a boundary, and has a first region on the upper side of the bent portion and a second region on the lower side.

  When the first region and the second region of each pixel are compared, the formation directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the alignment processing direction of the liquid crystal alignment film described later is used as a reference, the electrode element of the pixel electrode is formed to form an angle of + 15 ° (clockwise) in the first region of the pixel, and in the second region of the pixel. The electrode elements of the pixel electrode are formed so as to form an angle of −15 ° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotation operation (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode are mutually in the substrate plane. It is comprised so that it may become a reverse direction. The liquid crystal aligning agent (B) obtained in the liquid crystal aligning agent synthesis example 2 was spin-coated on the prepared substrate with electrodes.

Subsequently, after drying for 90 seconds with an 80 degreeC hotplate, it baked for 30 minutes with a 200 degreeC hot-air circulation type oven, and formed the liquid crystal aligning film with a film thickness of 100 nm. Subsequently, the coating film surface was irradiated with 313 nm polarized ultraviolet rays through a polarizing plate at 50 mJ / cm ² . Further, a coating film was similarly formed on a glass substrate having a columnar spacer having a height of 4 μm on which no electrode was formed as a counter substrate, and an orientation treatment was performed. A sealant (XN-1500T manufactured by Kyoritsu Chemical Co., Ltd.) was printed on the liquid crystal alignment film of one substrate. Next, the other substrate was bonded so that the liquid crystal alignment film faces each other and the alignment direction was 0 °, and then the sealing agent was cured to produce an empty cell. Into this empty cell, the polymerizable compound-containing liquid crystal (LC5) obtained in Preparation Example 5 was injected by a reduced pressure injection method, the injection port was sealed, and the configuration of an IPS (In-Plane Switching) mode liquid crystal display element was obtained. A provided liquid crystal cell was obtained.

After producing the liquid crystal cell, a realignment treatment was performed in an oven at 120 ° C. for 60 minutes. Thereafter, in a state where the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited, the liquid crystal cell was irradiated with ultraviolet rays of 5 J / cm ² (secondary irradiation) that passed through a 365 nm band-pass filter.

(Comparative Example 2)
A liquid crystal cell was prepared in the same manner as in Example 5 except that the liquid crystal composition (LC6) containing the polymerizable compound [RM4] obtained in Comparative Preparation Example 2 was used instead of the liquid crystal composition (LC5). Was made.

(Comparative Example 3)
A liquid crystal cell was produced in the same procedure as in Example 5 except that secondary irradiation was not performed.

<Afterimage evaluation>
The liquid crystal cell for IPS mode produced in Example 5 and Comparative Examples 2 and 3 was installed between two polarizing plates arranged so that the polarization axes were orthogonal to each other, and the backlight was turned on with no voltage applied. The arrangement angle of the liquid crystal cell was adjusted so that the luminance of transmitted light was minimized. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the pixel was darkest to the angle at which the first region was darkest was calculated as the initial orientation azimuth. Next, an AC voltage of 30 Hz and 8 V _PP was applied at room temperature for 72 hours. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left as it was at room temperature for 1 hour. After being allowed to stand, the orientation azimuth angle was measured in the same manner, and the difference between the orientation azimuth angles before and after AC driving was calculated as an angle Δ (deg.).

  Table 3 shows the results of afterimage evaluation. As shown in Table 3, the liquid crystal cell of Example 5 using the polymerizable compound [RM2] having a hydrogen-bonding functional group (carboxyl group) was compared using the polymerizable compound [RM4] having no carboxyl group. Compared with the liquid crystal cell of Example 2 or Comparative Example 3 in which secondary irradiation is not performed, the difference in orientation azimuth angle before and after AC driving was very small. This is because, like the measurement result of the response speed described above, the polymerizable compound [RM2] has a highly polar carboxyl group, so that the solubility in the liquid crystal is improved, and the carboxyl group and one or more aromatic rings This is thought to be due to the formation of pseudo mesogenic structures between molecules.

  Therefore, a liquid crystal display element containing a polymerizable compound that forms hydrogen bonds between molecules in the liquid crystal layer can greatly reduce the difference in orientation azimuth even after secondary irradiation with ultraviolet light (365 nm) on the long wavelength side, It was found that generation can be suppressed.

  The present invention is applicable to a PSA type liquid crystal display element in which a polymerizable compound is added to a liquid crystal layer and the alignment direction of the liquid crystal is controlled by polymerization of the polymerizable compound and a method for manufacturing the liquid crystal display element. This PSA-type liquid crystal display element is combined with a photo-alignment method to provide not only a vertical electric field drive method (VA method, TN method, OCB method, etc.) but also a horizontal electric field drive method (IPS method, FFS method). It can also be applied to. Since the liquid crystal display element of the present invention has a highly sensitive alignment fixing ability and excellent afterimage characteristics, it can be suitably used for a large-screen high-definition liquid crystal television.

Claims (10)

A liquid crystal comprising a pair of substrates facing each other, a liquid crystal layer sandwiched between the substrates, and a liquid crystal alignment film obtained from a liquid crystal alignment agent containing a polymer on at least one liquid crystal layer side of the substrate A display element,
The liquid crystal layer is formed from a liquid crystal composition containing a polymerizable compound and a liquid crystal,
The polymerizable compound has a polymerizable unsaturated bond group, a hydrogen-bonding functional group, and at least one or more aromatic rings in the vicinity of the functional group, and has the following formulas [2-1] to [2- 3], wherein the functional group forms a mesogen structure by forming a hydrogen bond between molecules.

The liquid crystal display element according to claim 1, wherein the polymer has a group for vertically aligning a liquid crystal in a side chain. The liquid crystal display element according to claim 2 , wherein the polymer further has a photopolymerizable group in a side chain. The liquid crystal display element according to claim 3 , wherein the photopolymerizable group is at least one selected from the following formulas [3-1] to [3-7].

The liquid crystal display element according to claim 1, wherein the polymer has a photoreactive group. The liquid crystal display element according to claim 5 , wherein the photoreactive group is at least one selected from the following formulas [4-1] to [4-5].

The said polymer contains at least 1 chosen from the polyimide precursor and the polyimide obtained by imidating it, polysiloxane, or poly (meth) acrylate, It is any one of Claims 1-6 characterized by the above-mentioned. The liquid crystal display element as described. The liquid crystal display element according to any one of claims 2 to 4 , further comprising a liquid crystal cell manufactured by irradiating ultraviolet rays while applying a voltage to the liquid crystal layer. The liquid crystal display element according to claim 5 , further comprising a liquid crystal cell manufactured by irradiating the liquid crystal layer with polarized ultraviolet rays. Forming a liquid crystal alignment film from a liquid crystal aligning agent containing a polymer on at least one of the pair of substrates,
The pair of substrates are opposed to each other so that the liquid crystal alignment film is inside,
Between the substrate, it possesses a polymerizable unsaturated bond group, a functional group forming a mesogenic structure by forming a hydrogen bond between molecules, and at least one or more aromatic rings in the vicinity of the functional group, Forming a liquid crystal layer by sandwiching a liquid crystal composition containing at least one polymerizable compound selected from the following formulas [2-1] to [2-3] and a liquid crystal;
A method for producing a liquid crystal display element, wherein the polymerizable compound is polymerized by irradiating the liquid crystal layer with ultraviolet rays.