JP6243862B2 - Method for manufacturing liquid crystal alignment film, method for manufacturing liquid crystal display device, and liquid crystal display device - Google Patents

Description

  The present invention relates to a method for producing a liquid crystal alignment film, a method for producing a liquid crystal display device, and a liquid crystal display device having a liquid crystal alignment film produced by the method for producing a liquid crystal alignment film.

Liquid crystal displays (LCDs) are widely used for monitors such as personal computers and smartphones and television applications because of their various advantages, such as low voltage and low power consumption, enabling miniaturization and thinning.
Such a liquid crystal display device has a liquid crystal cell and two polarizing plates disposed on both sides of the liquid crystal cell, and the liquid crystal cell is disposed to face each other with the liquid crystal layer and the liquid crystal layer interposed therebetween. In general, the substrate is provided with an alignment film for aligning the liquid crystal constituting the liquid crystal layer.

As such an alignment film, for example, Patent Document 1 describes a “liquid crystal alignment film containing polyoxazole as a main component” for performing an alignment treatment by rubbing ([Claim 1]).
Patent Document 2 discloses that a photoactive group is bonded as an active group to any one of a polybenzoxazole-based compound, a polybenzothiazole-based compound, and a polybenzimidazole-based compound that is subjected to alignment treatment by light. An alignment film made of a polymer ”is described ([Claim 1]).

JP 2000-122067 A JP 2008-077050 A

  The inventor examined the alignment films described in Patent Documents 1 and 2, and in the alignment film described in Patent Document 1, streaky alignment unevenness occurred after the rubbing treatment, which was described in Patent Document 2. The alignment film was found to be inferior in light resistance.

  Accordingly, an object of the present invention is to provide a method for producing a liquid crystal alignment film, a method for producing a liquid crystal display device, and a liquid crystal display device that have a good alignment state and excellent light resistance.

As a result of intensive studies to achieve the above-mentioned problems, the present inventor conducted heat treatment and photo-alignment treatment in a specific wavelength region on a film containing a polymer containing a repeating unit having a predetermined structure. The present inventors have found that a liquid crystal alignment film having a good state and excellent light resistance can be produced.
That is, it has been found that the above object can be achieved by the following configuration.

[1] An application step of applying a curable composition containing a polymer having a repeating unit represented by formula (1) described later on a substrate to form a film;
A heat treatment step for applying heat treatment to the film to form a film subjected to the heat treatment;
And a photo-alignment treatment step of producing a liquid crystal alignment film by subjecting the heat-treated film to an alignment treatment with light having a wavelength of 313 nm or less.

[2] An application step of applying a curable composition containing a polymer having a repeating unit represented by the formula (1) described later on a substrate to form a film;
A photo-alignment treatment step of performing an alignment treatment on the film with light having a wavelength of 313 nm or less, and forming a film subjected to the alignment process;
And a photo-alignment treatment step of producing a liquid crystal alignment film by performing heat treatment on the film subjected to the alignment process.

[3] The method for producing a liquid crystal alignment film according to [1] or [2], wherein the polymer is a polymer having a repeating unit represented by formula (2) described later.
[4] The method for producing a liquid crystal alignment film according to any one of [1] to [3], wherein the polymer is a polymer having a repeating unit represented by formula (3) described later.
[5] The polymer according to any one of [1] to [4], wherein the polymer is a polymer having a repeating unit represented by formula (3) described later and a repeating unit represented by formula (4) described later. A method for producing a liquid crystal alignment film.
[6] The method for producing a liquid crystal alignment film according to any one of [1] to [5], wherein the curable composition further contains a curing catalyst.
[7] The method for producing a liquid crystal alignment film according to [6], wherein the curing catalyst is a base catalyst or a latent base catalyst.
[8] A method for manufacturing a liquid crystal display device, comprising a step of forming a liquid crystal alignment film by the method for manufacturing a liquid crystal alignment film according to any one of [1] to [7].

[9] A liquid crystal display device having a liquid crystal layer, and a first substrate and a second substrate disposed to face each other across the liquid crystal layer,
A liquid crystal alignment film produced by the method for producing a liquid crystal alignment film according to any one of [1] to [7] at least partially between the liquid crystal layer and the first substrate and / or the second substrate A liquid crystal display device.
[10] The liquid crystal display device according to [9], wherein the liquid crystal constituting the liquid crystal layer is a horizontally aligned liquid crystal.

  According to the present invention, it is possible to provide a method for manufacturing a liquid crystal alignment film, a method for manufacturing a liquid crystal display device, and a liquid crystal display device that have a good alignment state and excellent light resistance.

Hereinafter, the present invention will be described in detail.
The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.
In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Method for producing liquid crystal alignment film]
In the method for producing a liquid crystal alignment film according to the first aspect of the present invention, a curable composition containing a polymer having a repeating unit represented by formula (1) described later is applied on a substrate to form a film. A photo-alignment process for forming a liquid crystal alignment film by applying a heat treatment to the film, heat-treating the film to form a heat-treated film, and subjecting the heat-treated film to an alignment treatment with light having a wavelength of 313 nm or less A liquid crystal alignment film having a processing step.
Moreover, the manufacturing method of the liquid crystal aligning film which concerns on the 2nd aspect of this invention apply | coats the curable composition containing the polymer which has a repeating unit represented by Formula (1) mentioned later, and forms the membrane | film | coat. A liquid crystal alignment film is prepared by performing an alignment process with a light having a wavelength of 313 nm or less, forming a film subjected to the alignment process, and performing a heat treatment on the film subjected to the alignment process. A liquid crystal alignment film having a photo-alignment treatment step.
That is, a method for manufacturing a liquid crystal alignment film according to the first aspect of the present invention and a method for manufacturing a liquid crystal alignment film according to the second aspect of the present invention (hereinafter, these are collectively abbreviated as “the manufacturing method of the present invention”. .) Is a manufacturing method that differs only in the order of the heat treatment step and the photo-alignment treatment step.

The production method of the present invention can produce a liquid crystal alignment film having a good alignment state and excellent light resistance by having heat treatment and photo-alignment treatment steps in no particular order.
Although this is not clear in detail, the inventor presumes as follows.
That is, an oxazole ring is produced in a polymer having a repeating unit represented by the formula (1) described later by heat treatment, and this oxazole ring is decomposed by applying an alignment treatment with light having a short wavelength of 313 nm or less, and deflected. This is probably because a certain direction is selectively decomposed by light.
Next, each processing step in the production method of the present invention will be described in detail.

[Coating process]
The coating process which the manufacturing method of this invention has is a process of apply | coating the curable composition mentioned later and forming a membrane | film | coat.

<Curable composition>
The curable composition is not particularly limited as long as it is a curable composition containing a polymer having a repeating unit represented by the following formula (1), but may contain a curing catalyst or a solvent described later.

(polymer)
The polymer contained in the curable composition is a polymer having a repeating unit represented by the following formula (1).

Here, X in Formula (1) represents a tetravalent organic group containing an aromatic ring, R represents a hydrogen atom or a monovalent organic group, L represents an alkylene group, and n represents 2 to 2 Represents an integer of 10,000. X in each repeating unit may be the same or different, R in each repeating unit may be the same or different, and L in each repeating unit may be the same or different. May be.

Here, specifically as a tetravalent organic group containing the aromatic ring which X shows, the organic group shown below is mentioned suitably, for example. In the tetravalent organic group shown below, “*” represents a connecting portion with —NH— in the above formula (1), and “**” represents a connecting portion with —OR in the above formula (1). Represent.

R is preferably a hydrogen atom, and examples of the monovalent organic group represented by R include an alkyl group having 1 to 6 carbon atoms.
R may represent a group that forms an acetal structure by linking to —O— linked to X in the formula (1). Specific examples include the following structures. In the structure shown below, *** represents a connecting portion with —O—.

The alkylene group represented by L is preferably an alicyclic or linear alkylene group having 2 to 8 carbon atoms. Examples of the alicyclic alkylene group include a cyclohexane-1,4-diyl group. Examples of the linear alkylene group include an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an n-heptylene group, and an n-octylene group. It is done.
n is preferably an integer of 5 to 1000, and more preferably an integer of 10 to 500.

In the present invention, the repeating unit represented by the above formula (1) can be dissolved in a solvent such as PGMEA (propylene glycol methyl ether acetate) and MEDG (diethylene glycol methyl ethyl ether) that can be used for a large coater. It is preferable that the polymer which has is a polymer which has a repeating unit represented by following formula (2).
In the following formula (2), R, L, and n are all the same as those described in the above formula (1).

In the present invention, the polymer having a repeating unit represented by the above formula (1) is a polymer having a repeating unit represented by the following formula (3) from the viewpoint of strength and solvent resistance required for flat panel display applications. It is preferable that
In the following formula (3), R and n are the same as those described in the above formula (1).

In the present invention, it can be dissolved in a solvent such as PGMEA (propylene glycol methyl ether acetate) or MEDG (diethylene glycol methyl ethyl ether) that can be used for large coating machines, and the transparency required for flat panel display applications is improved. For this reason, the polymer having a repeating unit represented by the above formula (1) is a polymer having a repeating unit represented by the above formula (3) and a repeating unit represented by the following formula (4) (both Polymer). In addition, n in following formula (4) is the same as that of what was demonstrated in the said Formula (1), and m represents the integer of 2-8.
Moreover, the aspect of copolymerization is not specifically limited, A block copolymer may be sufficient and a random copolymer may be sufficient.

In this invention, it is preferable that the weight average molecular weights of the polymer which has a repeating unit represented by the said Formula (1) are 1000-100000, and it is more preferable that it is 10000-50000.
Here, the weight average molecular weight is measured using GPC (gel permeation chromatography) under the following conditions.
・ Column: Tosoh KF-804L (three)
・ Developing solvent: Tetrahydrofuran (THF)
-Column temperature: 40 ° C
・ Flow rate: 1.0 mL / min
・ Apparatus: HLC-8220 manufactured by Tosoh Corporation
-Calibration curve: TSK standard PSt series

(Curing catalyst)
In the present invention, it is preferable that the curable composition further contains a curing catalyst because the curability becomes fast and the productivity becomes good.
Examples of the curing catalyst include an acid catalyst, a base catalyst, and a latent base catalyst.
Here, examples of the acid catalyst include hydrogen halides such as hydrochloric acid; nitric acid, sulfuric acid, sulfurous acid, hydrogen sulfide, perchloric acid, hydrogen peroxide, carbonic acid such as formic acid and acetic acid; dodecylbenzenesulfonic acid and the like. Sulfonic acid; and the like.
Examples of the base catalyst include imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 5-methylimidazole, 1-ethylbenzimidazole, 1-propylimidazole, 1-butylimidazole, benzimidazole, 1-methylbenzimidazole, 2-methylbenzimidazole, 4-methylbenzimidazole, 5-methylbenzimidazole, 2,4-dimethylbenzimidazole, 2,5-dimethylbenzimidazole, 1,3,4,6,7, 8-hexahydro-2H-pyrimidopyrimidine, 1,3,4,6,7,8-hexahydro-1-methyl-2H-pyrimidopyrimidine, 1,2-dimethyl-tetrahydropyrimidine, 1,8-diazabicyclo- [ 5,4,0] -7-Undese 1,5-diazabicyclo- [4,3,0] -5-nonene, 1,4,5,6-tetrahydropyrimidine, 6- (dibutylamino) -1,8-diazabicyclo- [5,4,0] And -7-undecene.
The latent base catalyst is preferably a compound that generates a base catalyst by heat or acid. For example, 1- (tert-butoxycarbonyl) -piperidine, 1- (tert-butoxycarbonyl) -imidazole, 1- (tert -Butoxycarbonyl) -4-hydroxypiperidine and the like.
Of these, a base catalyst or a latent base catalyst is preferred because the curability is faster and the productivity is better.

(solvent)
The curable composition may contain a solvent from the viewpoint of workability applied on the substrate.
The solvent is preferably an organic solvent. Specifically, for example, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolidone (hereinafter, “ NMP "), N-vinyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, acetone, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol methyl ether, etc. The polar solvent is preferably mentioned.

<Board>
The substrate on which the curable composition is applied is not particularly limited and is preferably a transparent substrate. Specifically, for example, a soda glass plate having a silicon oxide film on its surface, low expansion glass, non-alkali glass, quartz, Examples include silicone, silicon nitride, and a composite substrate in which molybdenum, titanium, aluminum, copper, or the like is vapor-deposited on such a substrate.
These substrates are rarely used in the above-described form, and a multilayer laminated structure such as a thin film transistor (TFT) element may be formed depending on the form of the final product.

<Application method>
The method for applying the curable composition on the substrate is not particularly limited. Specifically, for example, a printing method (for example, gravure printing method, screen printing method, flexographic printing method, inkjet printing method, imprinting method, etc.) , Spin coating method, slit coating method, slit and spin coating method, dip coating method, curtain coating method and the like.

[Solvent removal step]
The production method of the present invention has a solvent removal step for removing any solvent contained in the curable composition from the film after the coating step described above and before the heat treatment step and the photo-alignment treatment step described later. You may do it.
The solvent removal step is a step of heating at about 80 to 150 ° C. for about 0.5 to 3 minutes when NMP is used as the solvent, although the processing conditions differ depending on the type and amount of the solvent. It is more preferable that it is a step of heating at about 90 to 120 ° C. for about 0.5 to 2 minutes.

[Heat treatment process]
In the first aspect of the present invention, the heat treatment step is a step of performing a heat treatment on the film formed in the coating step described above. In the second aspect of the present invention, the heat treatment step is formed in the coating step described above. This is a step of performing a heat treatment on a film obtained by subjecting the coated film to an orientation treatment described later (a film on which the orientation treatment has been performed).
By performing such heat treatment, the oxazole ring dehydrated and closed in the polymer having the repeating unit represented by the above formula (1), specifically, the repeating represented by the above formula (3) or (4) In a polymer having a unit, a polybenzoxazole skeleton is generated.

Examples of a method for performing a heat treatment on a film or a film subjected to an alignment treatment include, for example, a film that has been subjected to a film or an alignment treatment at a temperature of 180 to 350 ° C., preferably 200 to 300 ° C. A method of heating for 60 minutes is preferable.
The heat treatment is preferably performed using a heating device such as a hot plate or an oven. Further, the transparency can be further improved by performing the heat treatment in a nitrogen atmosphere.

[Photo-alignment treatment process]
In the first aspect of the present invention, the photo-alignment treatment step is a step of performing a photo-alignment treatment on the film that has been subjected to the heat treatment in the above-described heat treatment step. This is a step of performing a photo-alignment process on the film formed in the coating step.

  The photo-alignment treatment in the photo-alignment treatment step is not particularly limited except that light having a wavelength of 313 nm or less is used, but it is preferable to use polarized ultraviolet rays for obtaining uniform alignment. In this case, the method of irradiating polarized ultraviolet rays is not particularly limited. In addition, there is no restriction | limiting in particular as polarized light, For example, linearly polarized light, circularly polarized light, elliptically polarized light etc. are mentioned, Among these, linearly polarized light is preferable.

  Moreover, it is only necessary to obtain substantially polarized light, and non-polarized light may be irradiated at an angle inclined from the normal line of the thin film. In other words, non-polarized light may be irradiated from an oblique direction on the surface of the thin film. “Inclined irradiation” is not particularly limited as long as it is a direction inclined by a polar angle θ (0 <θ <90 °) with respect to the normal direction of the thin film surface, and can be appropriately selected according to the purpose. However, it is preferable that (theta) is 20-80 degrees.

Examples of the light source used include a xenon lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, and a metal halide lamp.
By using an interference filter, a color filter, or the like for ultraviolet rays obtained from such a light source, the wavelength range of irradiation can be limited. Moreover, linearly polarized light can be obtained by using a polarizing filter or a polarizing prism for the light from these light sources.

[Method for manufacturing liquid crystal display device]
The manufacturing method of the liquid crystal display device of the present invention includes a step of forming a liquid crystal alignment film by the above-described manufacturing method of the liquid crystal alignment film of the present invention (hereinafter abbreviated as “alignment film forming step” in this paragraph). Is the method.
Here, the steps other than the alignment film forming step are not particularly limited. For example, a step of forming a liquid crystal layer on the alignment film, a step of bonding substrates disposed opposite to each other with the liquid crystal layer interposed therebetween, and the like. Can adopt each process in the manufacturing method of a conventionally well-known liquid crystal display device suitably.

[Liquid Crystal Display]
A liquid crystal display device of the present invention is a liquid crystal display device having a liquid crystal layer, and a first substrate and a second substrate disposed to face each other with the liquid crystal layer interposed therebetween, wherein the liquid crystal layer and the first substrate And / or a liquid crystal display device having a liquid crystal alignment film produced by the above-described production method of the present invention at least partially between the substrate and the second substrate.

[Liquid crystal layer]
As a driving method for driving a liquid crystal layer used in the liquid crystal display device of the present invention, a TN (Twisted Nematic) method, a VA (Virtual Alignment) method, an IPS (In-Place-Switching) method, an FFS (Frings Field). Examples include, but are not limited to, a switching method and an OCB (Optical Compensated Bend) method.
Among these driving methods, the IPS method is preferable.
In the IPS liquid crystal cell, rod-like liquid crystal molecules are aligned substantially parallel to the substrate, and the liquid crystal molecules respond in a planar manner when an electric field parallel to the substrate surface is applied. That is, in the IPS system, the liquid crystal constituting the liquid crystal layer is a horizontally aligned liquid crystal. In the IPS system, black is displayed when no electric field is applied, and the absorption axes of a pair of upper and lower polarizing plates are orthogonal.

  Hereinafter, the present invention will be described in more detail based on examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the following examples.

<Synthesis Example 1>
In a four-necked separable flask equipped with a thermometer, a stirrer and a dry nitrogen gas inlet tube, 32.96 g (0.09 mol) of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane And 14.24 g (0.18 mol) of pyridine were dissolved in 132 g of NMP.
Next, the separable flask was cooled to maintain the temperature of the reaction system at −10 ° C., and while stirring under nitrogen flow, 6.33 g (0.0265 mol) of zevacoyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), 4-cyclohexyl dicarbonyl chloride (trade name 14-CHDC, manufactured by Nippon Light Metal Co., Ltd.) 12.91 g (0.0617 mol), 0.64 g (0.0081 mol) of acetyl chloride dissolved in NMP 87.01 g was added dropwise. Then, stirring was continued for 5 hours while maintaining the temperature of the reaction system at −10 ° C.
Next, the temperature of the reaction system was returned to room temperature, and the reaction solution was dropped into 20 times the amount of ion-exchanged water of the reaction solution to precipitate the resin component.
After filtering the resin component, it was dried in a vacuum dryer at 50 ° C. for 24 hours to obtain polyhydroxyamide (weight average molecular weight: 15000) represented by the following formula (5).
The curable composition (S-1) was prepared by diluting with NMP and butyl cellosolve so that the concentration of the resin component was 5% and the ratio of NMP and butyl cellosolve was 8: 2.

<Synthesis Example 2>
In a four-necked separable flask equipped with a thermometer, a stirrer and a dry nitrogen gas inlet tube, 32.96 g (0.09 mol) of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane And 14.24 g (0.18 mol) of pyridine were dissolved in 132 g of NMP.
Next, the separable flask was cooled to maintain the temperature of the reaction system at −10 ° C., while stirring under nitrogen flow, and 1.4-cyclohexyl dicarbonyl chloride (trade name 14-CHDC, manufactured by Nippon Light Metal Co., Ltd.) 18 .44 g (0.0882 mol) and 0.64 g (0.0081 mol) of acetyl chloride dissolved in 87.01 g of NMP were added dropwise, and stirring was continued for 5 hours while maintaining the temperature of the reaction system at −10 ° C. .
The temperature of the reaction system was returned to room temperature, and the reaction solution was added dropwise into 20 times the amount of ion-exchanged water of the reaction solution to precipitate the resin component.
After filtering the resin component, it was dried in a vacuum dryer at 50 ° C. for 24 hours to obtain polyhydroxyamide (weight average molecular weight: 15000) represented by the following formula (6).
The curable composition (S-2) was prepared by diluting with NMP and butyl cellosolve so that the concentration of the resin component was 5% and the ratio of NMP and butyl cellosolve was 8: 2.

<Synthesis Example 3>
In a four-necked separable flask equipped with a thermometer, a stirrer and a dry nitrogen gas inlet tube, 32.96 g (0.09 mol) of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane And 14.24 g (0.18 mol) of pyridine were dissolved in 132 g of NMP.
Next, the separable flask was cooled to maintain the temperature of the reaction system at −10 ° C., and while stirring under nitrogen flow, 1.4-cyclohexyl dicarbonyl chloride (trade name 14-CHDC, manufactured by Nippon Light Metal Co., Ltd.) 15 A solution obtained by dissolving 0.05 g (0.072 mol) in 87.01 g of NMP was added dropwise, and stirring was continued for 5 hours while maintaining the temperature of the reaction system at −10 ° C.
The temperature of the reaction system was returned to room temperature, and the reaction solution was added dropwise into 20 times the amount of ion-exchanged water of the reaction solution to precipitate the resin component.
After filtering the resin content, it was dried in a vacuum dryer at 50 ° C. for 24 hours to obtain polyhydroxyamide (weight average molecular weight: 19000) represented by the following formula (7).
The curable composition (S-3) was prepared by diluting with NMP and butyl cellosolve so that the concentration of the resin component was 5% and the ratio of NMP and butyl cellosolve was 8: 2.

<Synthesis Example 4>
In a four-necked separable flask equipped with a thermometer, a stirrer and a dry nitrogen gas inlet tube, 32.96 g (0.09 mol) of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane And 14.24 g (0.18 mol) of pyridine were dissolved in 132 g of NMP.
Next, the separable flask was cooled to keep the temperature of the reaction system at −10 ° C., and while stirring under nitrogen flow, 21.09 g (0.0882 mol) of sebacoyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), acetyl chloride A solution prepared by dissolving 0.64 g (0.0081 mol) in 87.01 g of NMP was added dropwise, and stirring was continued for 5 hours while maintaining the temperature of the reaction system at −10 ° C.
Next, the temperature of the reaction system was returned to room temperature, and the reaction solution was dropped into 20 times the amount of ion-exchanged water of the reaction solution to precipitate the resin component.
After filtering the resin content, it was dried in a vacuum dryer at 50 ° C. for 24 hours to obtain polyhydroxyamide (weight average molecular weight: 14000) represented by the following formula (8).
The curable composition (S-4) was prepared by diluting with NMP and butyl cellosolve so that the concentration of the resin component was 5% and the ratio of NMP and butyl cellosolve was 8: 2.

<Synthesis Example 5>
In the same manner as in Synthesis Example 1, polyhydroxyamide (weight average molecular weight: 15000) represented by the above formula (5) was obtained.
It is diluted with NMP and butyl cellosolve so that the concentration of the resin component is 5% and the ratio of NMP to butyl cellosolve is 8: 2, and butylimidazole (0.223 g, 0.0018 mol) is used as a curing catalyst (base catalyst). Was added to prepare a curable composition (S-5).

<Synthesis Example 6>
In the same manner as in Synthesis Example 1, polyhydroxyamide (weight average molecular weight: 15000) represented by the above formula (5) was obtained.
It is diluted with NMP and butyl cellosolve so that the concentration of the resin component is 5% and the ratio of NMP and butyl cellosolve is 8: 2, and as a curing catalyst (acid catalyst), dodecylbenzenesulfonic acid (0.587 g, 0.0018). Mol) was added to prepare a curable composition (S-6).

<Comparative Synthesis Example 1>
In a four-necked separable flask equipped with a thermometer, a stirrer and a dry nitrogen gas inlet tube, 36.6 g (0.1 mol) of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane And 17.75 g (0.2 mol) of pyridine were dissolved in 165 g of NMP.
Next, the separable flask was cooled to maintain the temperature of the reaction system at −10 ° C., and while stirring under nitrogen flow, 20.3 g (0.1 mol) of terephthaloyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to 108.8 g of NMP. The solution dissolved in was dropped, and stirring was continued for 5 hours while maintaining the temperature of the reaction system at -10 ° C.
Next, the temperature of the reaction system was returned to room temperature, and the reaction solution was dropped into 20 times the amount of ion-exchanged water of the reaction solution to precipitate the resin component.
After filtering the resin content, it was dried in a vacuum dryer at 50 ° C. for 24 hours to obtain polyhydroxyamide (weight average molecular weight: 16000) represented by the following formula (9). The polyhydroxyamide represented by the following formula (9) is a polymer that does not satisfy L (alkylene group) represented by the above formula (1).
The curable composition (R-1) was prepared by diluting with NMP and butyl cellosolve so that the concentration of the resin component was 5% and the ratio of NMP and butyl cellosolve was 8: 2.

[Example 1]
On a 5 cm × 5 cm low alkali glass substrate having a 1 cm × 1 cm ITO (Indium Tin Oxide) transparent electrode in the center, and an electrode having a width of 1 mm formed so that connection to the outside is possible from there. The curable composition (S-1) was printed by flexographic printing to form a film.
Next, after preliminary drying (solvent removal) for 2 minutes on a hot plate at 80 ° C., heat treatment is performed for 60 minutes in a clean oven under a nitrogen atmosphere at 300 ° C., and a heat treatment with a film thickness of 100 nm is performed on the glass substrate. The applied film was formed.
In addition, when IR (infrared absorption spectrometry) spectrum of the heat-treated film was measured, peaks derived from oxazole were strongly observed at 1060 cm ⁻¹ and 1625 cm ^−1, and polybenzoxazole with polyhydroxyamide dehydrated and closed. It was confirmed that it was the main component.
Next, the film subjected to the heat treatment on the glass substrate is irradiated with 1 J / cm ² of polarized light centered on light of 313 nm or less using an ultraviolet polarized light exposure apparatus (HC-2150PUFM, manufactured by Lantec). After performing alignment treatment and forming a liquid crystal alignment film, a cell having a cell gap of 3 μm was prepared using an epoxy resin-based sealing material.
A liquid crystal composition for horizontal alignment (MLC-2055, manufactured by Merck & Co., Inc.) was injected into the cell, and the injection port was sealed with a UV curable sealant. A liquid crystal display device was manufactured.

[Example 2]
A liquid crystal display device was produced in the same manner as in Example 1 except that the curable composition (S-2) was used instead of the curable composition (S-1).

Example 3
A liquid crystal display device was produced in the same manner as in Example 1 except that the curable composition (S-3) was used instead of the curable composition (S-1).

Example 4
A liquid crystal display device was produced in the same manner as in Example 1 except that the curable composition (S-4) was used instead of the curable composition (S-1).

Example 5
A liquid crystal display device was produced in the same manner as in Example 1 except that the curable composition (S-5) was used instead of the curable composition (S-1).

Example 6
A liquid crystal display device was produced in the same manner as in Example 1 except that the curable composition (S-6) was used instead of the curable composition (S-1).

[Comparative Example 1]
Hardened by flexographic printing on a 5cm x 5cm low-alkali glass substrate with a 1mm x 1cm wide electrode that has a 1cm x 1cm ITO transparent electrode in the center and can be connected to the outside. The composition (S-1) was printed to form a film.
Next, after preliminary drying (solvent removal) for 2 minutes on a hot plate at 80 ° C., heat treatment is performed for 60 minutes in a clean oven under a nitrogen atmosphere at 300 ° C., and a heat treatment with a film thickness of 100 nm is performed on the glass substrate. The applied film was formed.
In addition, when the IR spectrum of the heat-treated film was measured, peaks derived from oxazole were strongly observed at 1060 cm ⁻¹ and 1625 cm ^−1, and polybenzoxazole having polyhydroxyamide dehydrated and ring-closed as a main component. Was confirmed.
Next, a rubbing process is performed on the heat-treated film on the glass substrate so that the rubbing direction is parallel between the upper and lower substrates, a liquid crystal alignment film is formed, and then a cell is formed using an epoxy resin-based sealing material. A cell with a gap of 3 μm was produced.
A liquid crystal composition for horizontal alignment (MLC-2055, manufactured by Merck & Co., Inc.) was poured into the cell, and the inlet was sealed with a UV curable sealant, and then the rubbing direction and direction were aligned on both sides of the cell. A liquid crystal display device was manufactured.

[Comparative Example 2]
A liquid crystal display device was produced in the same manner as in Example 1 except that the curable composition (R-1) was used instead of the curable composition (S-1).

[Comparative Example 3]
A liquid crystal display device was produced in the same manner as in Example 1 except that when performing the photo-alignment treatment, treatment was performed only with long wave polarized light using a 365 nm ultraviolet cut filter (LUX350, manufactured by Asahi Spectroscopic Co., Ltd.).

[Evaluation]
With respect to each of the manufactured liquid crystal display devices, the orientation, orientation sensitivity, light resistance, and transparency were evaluated by the following methods and criteria. These results are shown in Table 1 below.

<Orientation>
A liquid crystal alignment film similar to each of the produced liquid crystal display devices was formed on a glass substrate having a 1 cm × 1 cm ITO transparent electrode to a film thickness of 100 nm to prepare a sample.
The prepared sample is observed with a polarizing microscope with a magnification of 30 times, and the case where there is no alignment defect and uniform alignment is evaluated as “A”, and the case where there is a streak-like alignment defect is evaluated as “B”. did.

<Orientation sensitivity>
When manufacturing each liquid crystal display device, the lowest polarization irradiation energy value at which the alignment was completed 30 seconds after the injection was examined for the liquid crystal composition for horizontal alignment injected into the cell. It can be evaluated that productivity is so favorable that this figure is small.

<Light resistance>
After the forced light resistance test of Xe / 180mW / 72h was performed on each manufactured liquid crystal display device using a weatherometer, a ± 5V, 30Hz rectangular wave was applied to check light shielding / non-light shielding, The case of driving was evaluated as “A”, and the case of not driving or display unevenness was evaluated as “B”.

<Transparency>
Using the curable composition used for forming the liquid crystal alignment film of each liquid crystal display device, the film was printed on a glass substrate by flexographic printing to form a film.
Next, after preliminary drying (solvent removal) for 2 minutes on a hot plate at 80 ° C., heat treatment was performed for 60 minutes in a clean oven at 300 ° C., and a heat treatment having a film thickness of 100 nm was performed on the glass substrate. A sample in which was formed was produced.
About the produced sample, the transmittance | permeability of 400 nm (1 micrometer conversion) was measured, and what was the transmittance | permeability 90% or more was evaluated as "A" as what is excellent in transparency, and the transmittance | permeability was less than 90%. The thing was evaluated as "B" as being inferior in transparency.

As is clear from the results shown in Table 1, even in the case of using a curable composition containing a polymer having a repeating unit represented by the above formula (1), the alignment treatment by rubbing has a streak-like shape. It was found that alignment defects occur (Comparative Example 1).
Moreover, when the curable composition containing the polymer which has a repeating unit different from the repeating unit represented by said Formula (1) was used, even if it heat-processes and a photo-alignment process, it turns out that light resistance is inferior. (Comparative Example 2).
In addition, even when a curable composition containing a polymer having a repeating unit represented by the above formula (1) is used, when the alignment treatment is performed with light having a wavelength longer than 313 nm, the alignment is performed. It was found that the sensitivity was significantly inferior (Comparative Example 3).

On the other hand, when a curable composition containing a polymer having a repeating unit represented by the above formula (1) is used and subjected to a heat treatment and a photo-alignment treatment with light having a wavelength of 313 nm or less, the alignment state is good and the light resistance It turned out that the liquid crystal aligning film which is excellent also in the property can be formed (Examples 1-6).
In particular, from the comparison between Examples 1 to 4 and Examples 5 to 6, by blending a curing catalyst with the curable composition, the lowest polarized irradiation energy value for completing the orientation of the liquid phase layer is reduced, and the liquid crystal It has been found that the productivity of the display device is improved.
Furthermore, from the comparison between Example 5 and Example 6, it was found that when a base catalyst was used as the curing catalyst, the lowest polarized light irradiation energy value for completing the orientation of the liquid phase layer became smaller.

Claims (10)

Applying a curable composition containing a polymer having a repeating unit represented by the following formula (1) on a substrate to form a film;
A heat treatment step for applying a heat treatment to the film to form a film subjected to the heat treatment;
And a photoalignment treatment step of producing a liquid crystal alignment film by subjecting the heat-treated film to an alignment treatment with light having a wavelength of 313 nm or less.

Here, X in the formula (1) represents a tetravalent organic group containing an aromatic ring, R represents a hydrogen atom or a monovalent organic group, L represents an alkylene group, and n represents 2 Represents an integer of -10000. X in each repeating unit may be the same or different, R in each repeating unit may be the same or different, and L in each repeating unit may be the same or different. May be. Applying a curable composition containing a polymer having a repeating unit represented by the following formula (1) on a substrate to form a film;
The film is subjected to an alignment treatment with light having a wavelength of 313 nm or less, and a photo-alignment treatment step of forming a film subjected to the alignment treatment;
And a photo-alignment treatment step of producing a liquid crystal alignment film by performing heat treatment on the film subjected to the alignment process.

Here, X in the formula (1) represents a tetravalent organic group containing an aromatic ring, R represents a hydrogen atom or a monovalent organic group, L represents an alkylene group, and n represents 2 Represents an integer of -10000. X in each repeating unit may be the same or different, R in each repeating unit may be the same or different, and L in each repeating unit may be the same or different. May be. The manufacturing method of the liquid crystal aligning film of Claim 1 or 2 whose said polymer is a polymer which has a repeating unit represented by following formula (2).

Here, R in said Formula (2) represents a hydrogen atom or a monovalent organic group each independently, L represents an alkylene group, and n represents the integer of 2-10000. R in each repeating unit may be the same or different, and L in each repeating unit may be the same or different. The manufacturing method of the liquid crystal aligning film of any one of Claims 1-3 whose said polymer is a polymer which has a repeating unit represented by following formula (3).

Here, R in said Formula (3) represents a hydrogen atom or a monovalent organic group each independently, and n represents the integer of 2-10000. R in each repeating unit may be the same or different. The liquid crystal aligning film of any one of Claims 1-4 whose said polymer is a polymer which has a repeating unit represented by following formula (3), and a repeating unit represented by following formula (4). Manufacturing method.

Here, R in said Formula (3) represents a hydrogen atom or a monovalent organic group each independently, and n represents the integer of 2-10000. R in each repeating unit may be the same or different.
Moreover, R in said Formula (4) represents a hydrogen atom or a monovalent organic group each independently, m represents the integer of 2-8, n represents the integer of 2-10000. R in each repeating unit may be the same or different.   The method for producing a liquid crystal alignment film according to claim 1, wherein the curable composition further contains a curing catalyst.   The method for producing a liquid crystal alignment film according to claim 6, wherein the curing catalyst is a base catalyst or a latent base catalyst.   The manufacturing method of a liquid crystal display device which has a process of forming a liquid crystal aligning film with the manufacturing method of the liquid crystal aligning film of any one of Claims 1-7. A liquid crystal display device having a liquid crystal layer, and a first substrate and a second substrate disposed opposite to each other with the liquid crystal layer interposed therebetween,
The liquid crystal produced by the method for producing a liquid crystal alignment film according to claim 1, at least partly between the liquid crystal layer and the first substrate and / or the second substrate. A liquid crystal display device having an alignment film.   The liquid crystal display device according to claim 9, wherein the liquid crystal constituting the liquid crystal layer is a horizontally aligned liquid crystal.