JP2009258555A - Composition for forming liquid crystal alignment film and method for manufacturing liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal alignment film forming composition capable of forming a liquid crystal alignment film having no irregularity of a film thickness (irregular stripes) and having a uniform and flat surface even if the film is formed on a large substrate by using a droplet discharging method, and to provide a method for manufacturing a liquid crystal display device using the composition. <P>SOLUTION: The liquid crystal alignment film forming composition is used for forming a liquid crystal alignment film by the droplet discharging method. The composition contains a mixed solvent containing a first organic solvent A whose surface tension is not higher than 37 mN/m and a second organic solvent B whose surface tension is lower than 32 mN/m and a liquid crystal alignment film forming material dissolved in the mixed solvent. Each of the first organic solvent A and the second organic solvent B is composed of a single or more sorts of organic solvents. The first organic solvent A contains a high boiling point organic solvent A1 whose boiling point is 235°C and viscosity is not higher than 4 mPa s at 20°C as the organic solvent composing the first organic solvent A. In the high boiling point organic solvent A1, a mixture rate to the whole mixed solved is not smaller than 20 wt.%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a composition for forming a liquid crystal alignment film used when forming a liquid crystal alignment film by a droplet discharge method, and a method for manufacturing a liquid crystal display device using the same.

  Conventionally, as a method for forming a liquid crystal alignment film in a liquid crystal display device, a flexographic printing method or a spin coating method has been generally used. However, in the flexographic printing method, the plate maintenance is complicated, and more ink than necessary is used to spread the ink on the plate, so that the ink is wasted. On the other hand, even in the spin coating method, although a large amount of ink is required, the material actually used for film formation is about 10% of the input material, and the remaining 90% is discarded. After all, there was a drawback that ink wasted a lot.

Against this background, in recent years, it has been proposed to use a droplet discharge method typified by an inkjet method as a method for forming a liquid crystal alignment film. The droplet discharge method can dispose a necessary amount of ink at a necessary location, and therefore, waste of material (ink) is small. Therefore, it is advantageous in terms of material cost and has attracted particular attention in recent years.
In order to form a liquid crystal alignment film using this droplet discharge method, a solution (a composition for forming a liquid crystal alignment film) in which a liquid crystal alignment film forming material such as polyimide or polyamic acid is dissolved in an appropriate solvent is used. Is discharged onto a substrate (liquid crystal alignment film forming surface) by a droplet discharge method, further dried to form a coating film, and then the liquid crystal alignment ability is imparted to the coating film to form a liquid crystal alignment film.

Here, as a composition for forming a liquid crystal alignment film for forming a liquid crystal alignment film by a droplet discharge method (inkjet method), particularly the solvent composition thereof, γ-butyrolactone is mainly used in flexographic printing. (GBL), butyl cellosolve (BC [ethylene glycol monobutyl ether]), and N-methyl-2-pyrrolidone (NMP) are usually used in combination (for example, see Patent Document 1). Besides these, for example, those using N-dimethyl-2-imidazolidinone or propylene carbonate are also known (for example, Patent Document 2). A composition for forming a liquid crystal alignment film for discharging droplets is formed by appropriately adjusting the concentration of solid content (material for forming a liquid crystal alignment film) with respect to a mixed solvent composed of such a solvent.
JP 2003-295195 A JP 2006-30961 A

By the way, particularly when a large substrate is used, a multi-head in which a plurality of discharge heads are connected as an ink jet device (droplet discharge device), and a composition for forming a liquid crystal alignment film is discharged from each discharge head. Then, a liquid crystal alignment film is formed.
However, when the composition for forming a liquid crystal alignment film is discharged onto a large substrate using such a multi-head, unevenness in the film thickness (straight unevenness) due to the connecting portion of the head occurs in the liquid crystal alignment film obtained after drying. May end up.
As a cause of such film thickness unevenness,
(1) Drying due to time difference (time lag) between heads (2) Discharge amount difference between heads (3) Landing position shift due to flying flight of droplet (position accuracy)
And so on.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal alignment film that is uniform and flat even on a large substrate by a droplet discharge method without causing unevenness of film thickness (straight unevenness). An object of the present invention is to provide a composition for forming a liquid crystal alignment film that can be formed and a method for producing a liquid crystal display device using the composition.

  The composition for forming a liquid crystal alignment film of the present invention is a composition for forming a liquid crystal alignment film used for forming a liquid crystal alignment film by a droplet discharge method, and is a first organic solvent having a surface tension of 37 mN / m or more. A mixed solvent containing A and a second organic solvent B having a surface tension of less than 32 mN / m, and a liquid crystal alignment film forming material dissolved in the mixed solvent, the first organic solvent A and the second organic solvent B are each composed of a single kind or a plurality of kinds of organic solvents, and the first organic solvent A is an organic solvent constituting the first organic solvent A and has a boiling point of 235 ° C. or higher. And a high boiling point organic solvent A1 having a viscosity at 20 ° C. of 4 mPa · s or less, wherein the high boiling point organic solvent A1 has a mixing ratio of 20% by weight or more in the entire mixed solvent. It is said.

  According to this composition for forming a liquid crystal alignment film, the organic solvent constituting the first organic solvent A is a high-boiling organic solvent having a boiling point of 235 ° C. or higher and a viscosity at 20 ° C. of 4 mPa · s or lower. Since the mixing ratio of the high boiling point organic solvent A1 to the entire mixed solvent is 20% by weight or more, for example, when a large substrate is used and a multi-head is used as a droplet discharge device However, the composition is uniformly spread on the substrate and further dried to obtain a uniform and flat liquid crystal alignment film free from unevenness of the film thickness (straightening) caused by the connecting portion of the head. be able to.

  That is, a low-viscosity high-boiling organic solvent A1 having a boiling point of 235 ° C. or higher and a viscosity at 20 ° C. of 4 mPa · s or lower is blended and contained so that the mixing ratio is 20% by weight or more. Therefore, the composition for forming a liquid crystal alignment film containing the high-boiling organic solvent A1 has a low viscosity as a whole and can be better wetted and spread on the substrate during discharge (coating). Drying is slowed by being relatively high. Therefore, the composition spreads well on the substrate even when the coating layer comprising the composition is dried, and the solid content (solute) is uniformly distributed on the substrate. By flattening, there is no unevenness of film thickness (straight unevenness) caused by the connecting portion of the head, and a uniform and flat liquid crystal alignment film is obtained.

Further, as described above, a mixed solvent containing the first organic solvent A that is generally a good solvent and has low wettability and the second organic solvent B that is generally poor and has high wettability is used. Therefore, by using the second organic solvent B having particularly high wettability, the first organic solvent A having low wettability can be suppressed, as well as the unevenness, as well as the rise of the edge portion due to the above-mentioned swelling. As a result, it is possible to reduce the possibility that the adjacent liquid droplets stick to each other due to excessive wetting and spread, and the resulting liquid crystal alignment film is not uniformly formed with a desired thickness.
Therefore, according to the composition for forming a liquid crystal alignment film of the present invention, a uniform and flat liquid crystal alignment film can be formed by a droplet discharge method even on a large substrate without unevenness in film thickness (straight unevenness). .

In the composition for forming a liquid crystal alignment film, the mixing ratio of the second organic solvent B in the entire mixed solvent is preferably 3% by weight or more and 50% by weight or less.
By blending 3% by weight or more of the second organic solvent B having high wettability, good wettability with respect to the substrate (liquid crystal alignment film forming surface) of the liquid crystal alignment film forming composition is ensured. In addition, by setting the content to 50% by weight or less, the second organic solvent B, which is a poor solvent, does not occupy the majority of the mixed solvent, thereby ensuring good solubility of the mixed solvent in the liquid crystal alignment film forming material. The

In the composition for forming a liquid crystal alignment film, the high boiling point organic solvent A1 preferably contains at least one of ethylene carbonate, propylene carbonate, and butylene carbonate.
Each of the solvents is a low-viscosity solvent having a boiling point of 235 ° C. or higher and a viscosity at 20 ° C. of 4 mPa · s or less. Therefore, the composition containing the solvent spreads well on the substrate. The solid content (solute) is uniformly distributed on the substrate. Therefore, the coating layer is further flattened, and thereby there is no film thickness unevenness (straight unevenness) caused by the connecting portion of the head, and a uniform and flat liquid crystal alignment film can be obtained.

In the composition for forming a liquid crystal alignment film, the first organic solvent A is N-methyl-2-pyrrolidone, γ-butyrolactone, N, as a low boiling organic solvent A2 other than the high boiling organic solvent A1. It preferably contains at least one of N′-dimethyl-2-imidazolidinone.
Each of the above-mentioned solvents is a good solvent having better solubility in the liquid crystal alignment film forming material. Therefore, by using at least one of these, a better mixed solvent for the liquid crystal alignment film forming material is obtained. Solubility is ensured. Each of these solvents is also a low-viscosity solvent having a viscosity at 20 ° C. of 4 mPa · s or less, so that the composition for forming a liquid crystal alignment film containing them can be well spread on the substrate.

In the liquid crystal alignment film forming composition, the second organic solvent B preferably contains at least one of diethylene glycol ethyl methyl ether, ethylene glycol monobutyl ether, and diethylene glycol diethyl ether.
Each of these solvents can improve the formation of the liquid crystal alignment film as confirmed by the experimental results described later. Each of these solvents is also a low-viscosity solvent having a viscosity at 20 ° C. of 4 mPa · s or less, so that the composition for forming a liquid crystal alignment film containing them can be well spread on the substrate.

In the composition for forming a liquid crystal alignment film, the solid content concentration of the material for forming a liquid crystal alignment film is 1 wt% or more and 10 wt% or less, and the viscosity is 3 mPa · s or more and 20 mPa · s or less, The surface tension is preferably adjusted to 30 mN / m or more and 45 mN / m or less.
This is because if the solid content concentration is less than 1% by weight, the resulting alignment film is too thin and may not be a good liquid crystal alignment film. If the solid content concentration exceeds 10% by weight, The resulting alignment film is too thick, and may not be a good liquid crystal alignment film. Also, the viscosity of the composition for forming a liquid crystal alignment film increases, and the discharge performance by the droplet discharge method decreases. It is.
In addition, by adjusting the viscosity to 3 mPa · s or more and 20 mPa · s or less, the fluidity is improved, and therefore a good and stable discharge property by the droplet discharge method can be ensured. Furthermore, by adjusting the surface tension to 30 mN / m or more and 45 mN / m or less, the wettability to the substrate surface is improved, and therefore a liquid crystal alignment film having a uniform thickness can be efficiently formed by a droplet discharge method. .

（式中、Ｐ^１は４価の有機基であり、Ｑ^１は２価の有機基を表す。）で示される繰り返し単位、および以下の式（II）

（式中、Ｐ^２は４価の有機基であり、Ｑ^２は２価の有機基を表す。）で示される繰り返し単位から選ばれる、少なくとも一種を有する重合体であるのが好ましい。 In the composition for forming a liquid crystal alignment film, the material for forming a liquid crystal alignment film is represented by the following formula (I):

(Wherein P ¹ is a tetravalent organic group, Q ¹ represents a divalent organic group), and the following formula (II)

(In the formula, P ² is a tetravalent organic group, and Q ² represents a divalent organic group.) A polymer having at least one selected from repeating units represented by

The method for producing a liquid crystal display device of the present invention is characterized by having a step of forming the liquid crystal alignment film by applying the liquid crystal alignment film forming composition to the substrate surface by a droplet discharge method.
According to this manufacturing method, there is no unevenness in film thickness (straightness), and for example, a uniform and flat liquid crystal alignment film can be obtained even on a large substrate, so that a high-quality liquid crystal display device can be produced at low cost. It can be manufactured efficiently.

The present invention will be described in detail below.
First, the liquid crystal alignment film forming composition of the present invention will be described.
The composition for forming a liquid crystal alignment film of the present invention (hereinafter sometimes referred to as “the composition of the present invention”) is an ink used for forming a liquid crystal alignment film by a droplet discharge method using a droplet discharge device. A liquid crystal alignment film formed by dissolving a mixed solvent containing a first organic solvent A having a surface tension of 37 mN / m or more and a second organic solvent B having a surface tension of less than 32 mN / m, and the mixed solvent. And a forming material.

  The first organic solvent A and the second organic solvent B are each constituted by a single type or a plurality of types of organic solvents. And the organic solvent which comprises the said 1st organic solvent A contains the high boiling point organic solvent A1 whose vapor pressure in 20 degreeC is 5 Pa or less, Such a high boiling point organic solvent A1 is the said mixed solvent whole The mixing ratio occupies 20% by weight or more.

First, specific examples of the mixed solvent will be described.
(Mixed solvent)
In the composition of the present invention, the first organic solvent A having a surface tension of 37 mN / m or more and the second organic solvent B having a surface tension of less than 32 mN / m are used as the solvent for dissolving the liquid crystal alignment film forming material. These are mixed to form a mixed solvent.

  The first organic solvent A is an aprotic polar solvent or a phenol solvent, and at least one solvent having a surface tension of 37 mN / m or more is selected and used. Examples of the aprotic polar solvent include amide solvents, sulfoxide solvents, ether solvents, nitrile solvents, and the like. Among these, from the viewpoint of efficiently forming a high-quality liquid crystal alignment film having no film thickness unevenness (smoothness unevenness) and excellent in smoothness, it is preferable to use an amide solvent or a sulfoxide solvent.

Examples of the amide solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoramide, tetramethylurea and the like.
Examples of the sulfoxide solvent include dimethyl sulfoxide and diethyl sulfoxide.

  Examples of the phenol solvent include cresols such as o-cresol, m-cresol and p-cresol; xylenols such as o-xylenol, m-xylenol and p-xylenol; phenol; o-chlorophenol, m-chlorophenol, halogenated phenols such as o-bromophenol and m-bromophenol;

However, in the present invention, among these organic solvents, a high boiling point organic solvent A1 having a boiling point of 235 ° C. or higher and a viscosity at 20 ° C. of 4 mPa · s or lower is essential. Specifically, at least one of ethylene carbonate (ethylene carbonate), propylene carbonate (propylene carbonate), and butylene carbonate (butylene carbonate) is used as the high boiling point organic solvent A1. The boiling points and viscosities at 20 ° C. of these solvents are as follows.
・ Ethylene carbonate (ethylene carbonate)
Boiling point: 238 ° C. Viscosity: 2.5 mPa · s
・ Propylene carbonate (propylene carbonate)
Boiling point: 242 ° C Viscosity: 1.38 mPa · s
・ Butylene carbonate (butylene carbonate)
Boiling point: 240 ° C. Viscosity: 3.15 mPa · s

By using such a high-boiling organic solvent A1, as will be described later, in the composition of the present invention, unevenness in film thickness (straight unevenness) due to, for example, the connecting portion of the head occurs in the liquid crystal alignment film to be formed. Can be prevented.
Moreover, such high boiling point organic solvent A1 is mix | blended so that the mixing ratio which occupies for the said whole mixed solvent may be 20 weight% or more, Preferably it is mix | blended 50 weight% or more. This is because when the amount is less than 20% by weight, the vapor pressure of the entire composition increases, and thus the resulting liquid crystal alignment film is liable to be uneven in film thickness such as ridges at the edge and uneven stripes.

  Moreover, in this invention, you may contain the low boiling point organic solvent A2 whose boiling point is especially less than 235 degreeC as the 1st organic solvent A separately from such high boiling point organic solvent A1. Specifically, as the low-boiling organic solvent A2, N-methyl-2-pyrrolidone (boiling point: 202 ° C., viscosity: 1.65 mPa · s), γ-butyrolactone (boiling point: 204 ° C., viscosity: 1.7 mPa · s) ), N, N′-dimethyl-2-imidazolidinone (boiling point: 225 ° C., viscosity: 1.94 mPa · s). These low-boiling organic solvents A2 have a viscosity at 20 ° C. of 4 mPa · s or less, as indicated together with the boiling point in parentheses.

These solvents are good solvents having better solubility in the liquid crystal alignment film forming material. Therefore, by using at least one of these, better dissolution of the mixed solvent in the liquid crystal alignment film forming material is achieved. Sex can be secured.
Here, as described above, the first organic solvent A having a surface tension of not less than 37 mN / m and a relatively large surface tension has a low wettability with respect to the substrate surface on which the liquid crystal alignment film is formed. . Therefore, when only this first organic solvent A is blended, the composition blended with only this has poor wettability with respect to the substrate surface, and sufficient film formation cannot be performed.

Therefore, in the composition of the present invention, a solvent containing the second organic solvent B having a relatively small surface tension of less than 32 mN / m and thus good wettability is used as the mixed solvent. As the second organic solvent B, as described above, at least one solvent having a surface tension of less than 32 mN / m is selected and used.
Specifically, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), 1-methoxy-2-propanol, 1-methoxy-2-acetoxypropane Alcohol solvents such as ethylene glycol, propylene glycol, 1,4-butanediol and triethylene glycol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethylene glycol monomethyl ether, diethyl ether, ethylene glycol methyl ether , Ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol-n-butyl ether Ter (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, ethylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol butyl methyl ether, diethylene glycol monomethyl ether acetate Ether solvents such as diethylene glycol monoethyl ether acetate and tetrahydrofuran; ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, malo Ester solvents such as diethyl acid; halogenated hydrocarbon solvents such as dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene; n-hexane, n-heptane, and aliphatic hydrocarbon solvents such as n-octane; aromatic hydrocarbon solvents such as benzene, toluene and xylene; These solvents can be used alone or in combination of two or more.

  In the composition of the present invention, at least one of diethylene glycol ethyl methyl ether, ethylene glycol monobutyl ether, and diethylene glycol diethyl ether is particularly preferably used as the organic solvent constituting the second organic solvent B. This is because each of these solvents can improve the formation of the liquid crystal alignment film as confirmed by the experimental results described later.

  In addition, these solvents do not show good solubility in the liquid crystal alignment film forming material described later, and thus become a poor solvent, but as described above, because the wettability to the substrate surface is large, This contributes to prevention of unevenness in film thickness such as unevenness due to insufficient wetting and spreading of the composition for forming a liquid crystal alignment film, and protrusions (swelling) at the edge portion.

  The mixing ratio of the second organic solvent B to the entire mixed solvent is preferably 3% by weight or more and 50% by weight or less. By blending 3% by weight or more of the second organic solvent B having high wettability, it is possible to ensure good wettability with respect to the substrate (liquid crystal alignment film forming surface) of the liquid crystal alignment film forming composition. Therefore, it is possible to form a uniform and flat liquid crystal alignment film. Moreover, the second organic solvent B, which is a poor solvent, does not occupy the majority of the mixed solvent by setting it to 50% by weight or less, thereby ensuring good solubility of the mixed solvent in the liquid crystal alignment film forming material. Good film formability can be obtained.

  The mixed solvent containing the first organic solvent A and the second organic solvent B is a composition of the present invention (a composition for forming a liquid crystal alignment film) obtained by dissolving a liquid crystal alignment film forming material in the mixed solvent. The preferred mixing ratio of the first organic solvent A and the second organic solvent B varies depending on the use form of the product. That is, when the display method of the liquid crystal display device using this composition is the VA method, the mixing ratio of the first organic solvent A (good solvent) in the entire mixed solvent is 50 wt% or more and 70 wt% or less. The mixing ratio of the second organic solvent B (poor solvent) is 30 wt% or more and 50 wt% or less. When the display method of the liquid crystal display device is the IPS method, the mixing ratio of the first organic solvent A (good solvent) in the entire mixed solvent is set to 60 wt% or more and 95 wt% or less, and the second organic The mixing ratio of the solvent B (poor solvent) is set to 5% by weight or more and 40% by weight or less.

  Further, when the display method is the VA method, good film formability is ensured when the mixing ratio of the high boiling point organic solvent A1 in the entire mixed solvent is in the range of 20 wt% to 100 wt%. . On the other hand, in the case of the IPS system, in order to ensure good film formability, the mixing ratio of the high boiling point organic solvent A1 in the entire mixed solvent is set in the range of 20 wt% or more and 60 wt% or less. Is preferred.

Next, the liquid crystal alignment film forming material that is dissolved in the mixed solvent and has a solid content will be described.
(Liquid crystal alignment material)
The material for forming a liquid crystal alignment film used in the composition of the present invention is not particularly limited, and a conventionally known material for forming a liquid crystal alignment film can be used. Examples thereof include polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polysiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate, and the like.

  Among these, it has at least one selected from the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) for the reason that an alignment film having excellent liquid crystal alignment ability can be formed. A polymer is preferred.

  Examples of such a polymer include (i) a polyamic acid having a repeating unit represented by the formula (I), (ii) an imidized polymer having a repeating unit represented by the formula (II), Examples thereof include a block copolymer having an amic acid prepolymer having a repeating unit represented by the formula (I) and an imide prepolymer having a repeating unit represented by the formula (II). These may be used alone or in combination of two or more. When using in combination of 2 or more types, it is preferable to mix and use a polyamic acid and an imidized polymer.

(I) Polyamic acid A polyamic acid can be obtained by reacting a tetracarboxylic dianhydride and a diamine.
Examples of tetracarboxylic dianhydrides used for the synthesis of polyamic acid include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride. Anhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2 , 3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexane Tetracarboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetracarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracar Acid dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 2,3, 4,5-tetrahydrofurantetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c]- Furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c]- Furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c]- Furan-1,3-dione, 1,3,3a , 4,5,9b-Hexahydro-7-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a , 4,5,9b-Hexahydro-7-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a , 4,5,9b-Hexahydro-8-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a , 4,5,9b-Hexahydro-8-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a , 4,5,9b-Hexahydro-5,8-dimethyl-5 (tetra Dro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene -1,2-dicarboxylic dianhydride, bicyclo [2,2,2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxabicyclo [3,2, 1] Alicyclic tetracarboxylic acid such as octane-2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione), compounds represented by the following formulas (1) and (2) Dianhydride;

（式中、Ｒ^４、Ｒ^５、Ｒ^７及びＲ^８は、それぞれ独立して水素原子又はアルキル基を表し、Ｒ^６及びＲ^９は、それぞれ独立して芳香環を有する２価の有機基を表す。）

(In the formula, R ⁴ , R ⁵ , R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group, and R ⁶ and R ⁹ each independently represent a divalent organic group having an aromatic ring. To express.)

Aliphatic tetracarboxylic dianhydrides such as butanetetracarboxylic dianhydride;
Pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4′-bis ( 3,4-dicar Boxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidene diphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (Phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4 , 4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride, ethylene glycol-bis (anhydro trimellitate), propylene glycol-bis (anhydro trimellitate) 1,4-butanediol-bis (anhydrotrimellitate), 1,6-hexanediol-bis (anhydride) Trimellitate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate), the following formulas (3) to (6) An aromatic tetracarboxylic dianhydride such as an aromatic tetracarboxylic dianhydride having a steroid skeleton represented by These can be used alone or in combination of two or more.

  Examples of the diamine used for the synthesis of polyamic acid include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl sulfide, 4, 4'-diaminodiphenyl sulfone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 4,4 ' -Diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 6- Amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 3,4′-diaminodiphenyl ether 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene 2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 4,4′-methylene-bis (2-chloro) Nilin), 2,2 ′, 5,5′-tetrachloro-4,4′-diaminobiphenyl, 2,2′-dichloro-4,4′-diamino-5,5′-dimethoxybiphenyl, 3,3 ′ -Dimethoxy-4,4'-diaminobiphenyl, 1,4,4 '-(p-phenyleneisopropylidene) bisaniline, 4,4'-(m-phenyleneisopropylidene) bisaniline, 2,2'-bis [4- (4-Amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino- Aromatic diamines such as 2-trifluoromethyl) phenoxy] -octafluorobiphenyl;

  1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophorone diamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene methylene diamine, tricyclo [6.2.1.02,7] -undecylene dimethyl diamine, 4, Aliphatic and cycloaliphatic diamines such as 4'-methylenebis (cyclohexylamine);

  2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino-2,4 -Dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,3 , 5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl -S-triazine, 2,4-diamino-1,3,5-triazine, 4,6-diamino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6- Aminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6 Two primary amino groups in the molecule, such as phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine, and nitrogen atoms other than the primary amino group A diamine having the formula:

（式中、Ｒ^１０〜Ｒ^１３は、それぞれ独立して炭素数１〜１２の炭化水素基を表し、ｐ、ｒはそれぞれ独立して１〜３の整数であり、ｑは１〜２０の整数である。）で示されるジアミノオルガノシロキサン等が挙げられる。これらのジアミンは一種単独で、あるいは二種以上を組み合わせて用いることができる。

(Wherein R ^{10 to} R ¹³ each independently represent a hydrocarbon group having 1 to 12 carbon atoms, p and r are each independently an integer of 1 to 3, and q is an integer of 1 to 20) And the like, and the like. These diamines can be used alone or in combination of two or more.

When it is desired to impart pretilt angle expression to the composition of the present invention, a part or all of Q ¹ in the above formula (I) and / or Q ² in the above formula (II) is represented by the following formula (8) and It is preferably at least one group represented by (9).

（式中、Ｘ^１は、単結合、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨＣＯ−、−ＣＯＮＨ−、−Ｓ−又はアリーレン基であり、Ｒ^１４は、炭素数１０〜２０のアルキル基、炭素数４〜４０の脂環式骨格を有する１価の有機基又は炭素数６〜２０のフッ素原子を有する１価の有機基である。）

(In the formula, X ¹ represents a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S— or an arylene group, and R ¹⁴ represents the number of carbon atoms. A 10-20 alkyl group, a monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms, or a monovalent organic group having a fluorine atom having 6 to 20 carbon atoms.)

（式中、Ｘ^２、Ｘ^３はそれぞれ独立して、単結合、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨＣＯ−、−ＣＯＮＨ−、−Ｓ−又はアリーレン基であり、Ｒ^１５は、炭素数４〜４０の脂環式骨格を有する２価の有機基である。）

Wherein X ² and X ³ are each independently a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S— or an arylene group. R ¹⁵ is a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms.)

In the formula (8), examples of the alkyl group having 10 to 20 carbon atoms represented by R ¹⁴ include an n-decyl group, an n-dodecyl group, an n-pentadecyl group, an n-hexadecyl group, and an n-octadecyl group. , N-eicosyl group and the like.

Examples of the organic group having an alicyclic skeleton having 4 to 40 carbon atoms represented by R ¹⁴ in the formula (8) and R ¹⁵ in the formula (9) include cyclobutane, cyclopentane, cyclohexane, A group having a cycloalkane-derived alicyclic skeleton such as cyclodecane; a group having a steroid skeleton such as cholesterol or cholestanol; a group having a bridged alicyclic skeleton such as norbornene or adamantane. The organic group having an alicyclic skeleton may be a group substituted with a halogen atom, preferably a fluorine atom, or a fluoroalkyl group, preferably a trifluoromethyl group.

Furthermore, examples of the organic group having a fluorine atom having 6 to 20 carbon atoms represented by R ¹⁴ in the formula (8) include 6 carbon atoms such as an n-hexyl group, an n-octyl group, and an n-decyl group. In the above linear alkyl group; an alicyclic hydrocarbon group having 6 or more carbon atoms such as a cyclohexyl group or a cyclooctyl group; an organic group such as an aromatic hydrocarbon group having 6 or more carbon atoms such as a phenyl group or a biphenyl group Examples include a group in which part or all of the hydrogen atoms are substituted with a fluorine atom or a fluoroalkyl group such as a trifluoromethyl group.

As the arylene group ^X 1 to X ³ in the formula (8) and (9), a phenylene group, a tolylene group, a biphenylene group, and naphthylene group.

  Specific examples of the diamine having the group represented by the formula (8) include dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy-2, Preferred examples include 4-diaminobenzene and compounds represented by the following formulas (10) to (15).

  Specific examples of the diamine having a group represented by the formula (9) include diamines represented by the following formulas (16) to (18).

  The use ratio of the specific diamine with respect to the total amount of diamine varies depending on the size of the pretilt angle to be expressed. 5 to 100 mol% is preferable.

  The polyamic acid can be produced by reacting the above-described tetracarboxylic dianhydride and diamine in an appropriate organic solvent, usually at -20 ° C to + 150 ° C, preferably 0 to 100 ° C.

  The proportion of tetracarboxylic dianhydride and diamine used is preferably such that the proportion of the acid anhydride group of tetracarboxylic dianhydride is 0.2 to 2 equivalents relative to 1 equivalent of amino group of diamine. Is a ratio of 0.3 to 1.2 equivalents.

  The organic solvent used for the polyamic acid synthesis reaction is not particularly limited as long as it can dissolve the polyamic acid. For example, aprotic polar solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide; And phenolic solvents such as cresol, xylenol, phenol and halogenated phenol;

  The amount of organic solvent used (α) is usually such that the total amount (β) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight based on the total amount of the reaction solution (α + β). It is preferable that

  In addition, the poor solvent of a polyamic acid can be used together with the said organic solvent in the range in which the polyamic acid to produce | generate does not precipitate.

  Examples of the poor solvent for the polyamic acid include those exemplified as the poor solvent for the material for forming a liquid crystal alignment film. These solvents can be used alone or in combination of two or more.

A polyamic acid can be isolated by pouring a reaction solution containing a polyamic acid into a large amount of poor solvent to obtain a precipitate, and drying the precipitate under reduced pressure.
Moreover, a polyamic acid can be refine | purified by performing the process made to melt | dissolve the obtained polyamic acid in an organic solvent again, and to precipitate with a poor solvent once or several times.

(Ii) Imidized polymer The imidized polymer can be obtained by dehydrating and ring-closing the polyamic acid by a known method, for example, a method described in JP-A No. 2003-295195. In the imidized polymer, 100% of the repeating units may not be dehydrated and closed, and the ratio of the repeating units having an imide ring in all the repeating units (hereinafter also referred to as “imidation rate”) is 100%. It may be less.

  The imidation rate of the imidized polymer is not particularly limited, but is preferably 40 mol% or more, more preferably 70 mol% or more. By using a polymer having an imidization ratio of 40 mol% or more, a liquid crystal alignment film forming composition capable of forming a liquid crystal alignment film having a short afterimage erasing time can be obtained.

  The polymer used in the present invention may be a terminal-modified type having a controlled molecular weight. By using this terminal-modified polymer, it is possible to improve the application suitability of the composition for forming a liquid crystal alignment film without impairing the effects of the present invention.

  Such a terminal-modified polymer can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when synthesizing a polyamic acid. Here, examples of the acid monoanhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride. , N-hexadecyl succinic anhydride and the like. Examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, and n-undecylamine. , N-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine and the like. . Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

(Iii) Block copolymer The block copolymer synthesizes an amic acid prepolymer having an amino group or an acid anhydride group at the terminal and an imide prepolymer having an acid anhydride group or an amino group at the terminal, It can be obtained by bonding an amino group at the end of each prepolymer and an acid anhydride group.

  The amic acid prepolymer can be synthesized by the same method as the polyamic acid synthesis method described above. Further, the imide prepolymer can be synthesized in the same manner as the above-described imidized polymer synthesis method. The functional group at the end can be selected by adjusting the amounts of tetracarboxylic dianhydride and diamine during polyamic acid synthesis.

  In order to improve the adhesion to the substrate surface, the composition of the present invention may contain a functional silane-containing compound or an epoxy group-containing compound in addition to the mixed solvent and the liquid crystal alignment film forming material.

  There are no particular limitations on the functional silane-containing compound and epoxy group-containing compound used, and conventionally known compounds can be used. The mixing ratio of these functional silane-containing compound and epoxy group-containing compound is usually 40 parts by weight or less, preferably 30 parts by weight or less, with respect to 100 parts by weight of the liquid crystal alignment film forming material.

  The composition of the present invention can be produced by dissolving or dispersing, preferably dissolving, the liquid crystal alignment film-forming material and optionally a functional silane-containing compound in the mixed solvent.

  The solid content concentration of the liquid crystal alignment film-forming material in the composition of the present invention is selected in consideration of viscosity, surface tension, etc., but is preferably in the range of 1 wt% to 10 wt%. The This is because if the solid content concentration is less than 1% by weight, the resulting alignment film is too thin and may not be a good liquid crystal alignment film. In addition, if the solid content concentration exceeds 10% by weight, the resulting alignment film becomes too thick, which may not be a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment film forming composition increases. This is because the discharge performance by the droplet discharge method is lowered.

Although it does not restrict | limit especially about the viscosity of this invention composition, It is preferable to adjust to the range of 3 mPa * s or more and 20 mPa * s or less (20 degreeC). By adjusting the viscosity within this range, the fluidity is improved, and therefore a good and stable ejection property by the droplet ejection method can be ensured.
Further, the surface tension of the composition of the present invention is not particularly limited, but it is preferably adjusted in the range of 30 mN / m to 45 mN / m (20 ° C.). By adjusting the surface tension within this range, the wettability to the substrate surface is improved, and therefore a liquid crystal alignment film having a uniform thickness can be efficiently formed by the droplet discharge method.

  According to the composition of the present invention, the organic solvent constituting the first organic solvent A includes a high-boiling organic solvent A1 having a boiling point of 235 ° C. or higher and a viscosity at 20 ° C. of 4 mPa · s or lower, Since the mixing ratio of the high-boiling organic solvent A1 in the mixed solvent is 20% by weight or more, this composition can be obtained even when, for example, a large substrate is used and a multi-head is used as a droplet discharge device. By uniformly wetting and spreading the material on the substrate and further delaying the drying, a uniform and flat liquid crystal alignment film can be obtained without unevenness of the film thickness (straight unevenness) caused by the connecting portion of the head.

  That is, a low-viscosity high-boiling organic solvent A1 having a boiling point of 235 ° C. or higher and a viscosity at 20 ° C. of 4 mPa · s or lower is blended and contained so that the mixing ratio is 20% by weight or more. Therefore, the composition for forming a liquid crystal alignment film containing the high-boiling organic solvent A1 has a low viscosity as a whole and can be better wetted and spread on the substrate during discharge (coating). Drying is slowed by being relatively high. Therefore, the composition spreads well on the substrate even when the coating layer comprising the composition is dried, and the solid content (solute) is uniformly distributed on the substrate. By flattening, there is no unevenness of film thickness (straight unevenness) caused by the connecting portion of the head, and a uniform and flat liquid crystal alignment film is obtained.

Further, as described above, a mixed solvent containing the first organic solvent A that is generally a good solvent and has low wettability and the second organic solvent B that is generally poor and has high wettability is used. Therefore, by using the second organic solvent B having particularly high wettability, the first organic solvent A having low wettability can be suppressed, as well as the unevenness, as well as the rise of the edge portion due to the above-mentioned swelling. As a result, it is possible to reduce the possibility that the adjacent liquid droplets stick to each other due to excessive wetting and spread, and the resulting liquid crystal alignment film is not uniformly formed with a desired thickness.
Therefore, according to the composition for forming a liquid crystal alignment film of the present invention, a uniform and flat liquid crystal alignment film can be formed by a droplet discharge method even on a large substrate without unevenness in film thickness (straight unevenness). .

Next, the manufacturing method of the liquid crystal display device using the composition for liquid crystal aligning film formation of this invention is demonstrated.
The method for producing a liquid crystal display device of the present invention includes a step of applying the above-described composition of the present invention to the substrate surface by a droplet discharge method to form a liquid crystal alignment film.

The method for producing a liquid crystal display device of the present invention can be carried out, for example, using the production line for the liquid crystal display device shown in FIG.
As shown in FIG. 1, the liquid crystal display device manufacturing line I includes a cleaning device 1, a lyophilic processing device 2, a droplet discharge device 3a, a drying device 4, a baking device 5, a rubbing device 6, a liquid used in each process. A droplet discharge device 3b, a droplet discharge device 3c, a bonding device 7, a belt conveyor A connecting the devices, a drive device 8 for driving the belt conveyor A, and a control device 9 for controlling the entire liquid crystal display device production line I It is comprised by.

  An example of a droplet discharge device used in the present invention is shown in FIG. FIG. 2 is a diagram showing an outline of the configuration of the ink jet type ejection device 3a. The discharge device 3a is not particularly limited as long as it is a so-called inkjet discharge device. For example, there are a piezo-type discharge device that discharges droplets by compression using a piezo element, a thermal-type discharge device that generates bubbles by heating and foaming and discharges droplets, and the like.

  The discharge device 3a includes an inkjet head 22 that discharges a discharge (the composition of the present invention) onto a substrate. In the present embodiment, the inkjet head 22 is a multi-unit formed by connecting a plurality of ejection heads (not shown) including a head main body 24 and a nozzle forming surface 26 on which a large number of nozzles for ejecting ejection are formed. It is composed of a head. The above-described composition of the present invention is discharged onto the substrate from the nozzles on the nozzle forming surface 26 of the multi-head.

  Further, the discharge device 3a includes a table 28 on which a substrate is placed. The table 28 is installed to be movable in a predetermined direction, for example, the X-axis direction, the Y-axis direction, and the Z-axis direction. Further, the table 28 moves in the direction along the X axis as indicated by an arrow in the drawing, whereby the substrate conveyed by the belt conveyor A is placed on the table 28 and taken into the discharge device 3a.

  The ink jet head 22 is connected to a tank 30 that contains a discharge material discharged from a nozzle formed on the nozzle forming surface 26. In other words, the tank 30 and the inkjet head 22 are connected by a discharge material transport pipe 32 that transports the discharge material.

  The discharge material transfer pipe 32 includes a discharge material flow path portion ground joint 32a and a head portion bubble elimination valve 32b for preventing charging in the flow path of the discharge material transfer pipe 32. This head part bubble elimination valve 32b is used when suctioning the discharged substance in the inkjet head 22 with the suction cap 40 mentioned later. That is, when sucking the discharged material in the inkjet head 22 by the suction cap 40, the head part bubble elimination valve 32b is closed, and the discharged material does not flow from the tank 30 side. Then, when suction is performed with the suction cap 40, the flow rate of the suctioned product is increased, and the bubbles in the inkjet head 22 are quickly discharged.

  The discharge device 3a is a liquid for controlling the storage amount of the discharge material stored in the tank 30, that is, the height of the liquid surface 34a of the discharge material (the composition of the present invention) stored in the tank 30. A surface control sensor 36 is provided. The liquid level control sensor 36 keeps the height difference h (hereinafter referred to as the water head value) between the tip 27 of the nozzle forming surface 26 of the inkjet head 22 and the liquid level 34a in the tank 30 within a predetermined range. Take control. By controlling the height of the liquid level 34a, the discharge 34 in the tank 30 is sent to the inkjet head 22 with a pressure within a predetermined range. Then, the ejected material 34 can be stably ejected from the inkjet head 22 by sending the ejected material 34 at a pressure within a predetermined range.

  In addition, a suction cap 40 that sucks the ejected matter in the nozzles of the inkjet head 22 is disposed at a certain distance from the nozzle formation surface 26 of the inkjet head 22. The suction cap 40 is configured to be movable in the direction along the Z axis indicated by an arrow in FIG. 2, and is in close contact with the nozzle forming surface 26 so as to surround a plurality of nozzles formed on the nozzle forming surface 26. In addition, a sealed space is formed between the nozzle forming surface 26 and the nozzle can be blocked from outside air.

  In addition, the suction of the ejected matter in the nozzles of the ink jet head 22 by the suction cap 40 is performed when the ink jet head 22 is not ejecting the ejected matter 34, for example, the ink jet head 22 is retracted to a retreat position or the like. This is performed when 28 is retracted to a position indicated by a broken line.

A flow path is provided below the suction cap 40, and a suction valve 42, a suction pressure detection sensor 44 for detecting a suction abnormality, and a suction pump 46 including a tube pump are disposed in the flow path. Has been. Further, the discharge 34 sucked by the suction pump 46 and transported through the flow path is accommodated in a waste liquid tank 48.
In the following description, the droplet discharge devices 3b and 3c have the same configuration as the discharge device 3a except that the materials to be discharged are different.

Next, the present invention will be described in detail taking as an example the case of manufacturing the liquid crystal display device shown in FIG. FIG. 3 is a diagram schematically showing a cross section of the liquid crystal display device manufactured according to this embodiment.
The liquid crystal display device shown in FIG. 3 is a passive matrix transflective color liquid crystal display device. In the liquid crystal display device 50, a rectangular flat plate-like lower substrate 52a made of glass, plastic, or the like and an upper substrate 52b are arranged to face each other via a sealant and a spacer (not shown), and the lower substrate 52a and the upper substrate 52b. A liquid crystal layer 56 is sandwiched therebetween.

  A plurality of segment electrodes 58 and a liquid crystal alignment film 60 are formed between the lower substrate 52a and the liquid crystal layer 56 from the lower substrate 52a side. As shown in FIG. 3, the segment electrode 58 is formed in a stripe shape, and is formed of a transparent conductive film such as indium tin oxide (ITO). The liquid crystal alignment film 60 is formed of a liquid crystal alignment film forming material.

  A color filter 62, an overcoat film 66, a common electrode 68, and a liquid crystal alignment film 70 are formed between the upper substrate 52b and the liquid crystal layer 56 in this order from the upper substrate 52b side. The color filter 62 includes red (R), green (G), and blue (B) dye layers 62r, 62g, and 62b. Between the dye layers 62r, 62g, and 62b included in the color filter 62, the color filter 62 is provided. On the (boundary), a black matrix 64 made of metal such as resin black or chromium (Cr) having low light reflectance is formed. The dye layers 62r, 62g, and 62b constituting the color filter 62 are disposed so as to face the segment electrodes 58 formed on the lower substrate 52a.

The overcoat film 66 flattens the steps between the dye layers 62r, 62g, and 62b and protects the surface of each dye layer, and is formed of an inorganic film such as an acrylic resin, a polyimide resin, or a silicon oxide film. ing.
The common electrode 68 is formed of a transparent conductive film such as ITO, and is formed in a stripe shape at a position orthogonal to the segment electrode 58 formed on the lower substrate 52a.
The liquid crystal alignment film 70 is formed of a polyimide resin or the like.

  The liquid crystal display device shown in FIG. 3 can be manufactured through steps (S10) to (S19) as shown in FIG. Hereinafter, each step will be described in order.

(S10)
First, a substrate for forming a liquid crystal alignment film is prepared.
As the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, or polycarbonate can be used. As the transparent conductive film provided on one surface of the substrate, a film made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), or the like can be used. For patterning these transparent conductive films, a photo-etching method or a method using a mask in advance is used. In the present embodiment, the lower substrate 52a on which the segment electrode 58 is formed is used.

Next, the surface of the substrate on which the alignment film is formed is washed (S10). That is, the lower substrate 52a on which the segment electrode 58 is formed is transported to the cleaning device 1 by the belt conveyor A, and the lower substrate 52a transported by the belt conveyor A is taken into the cleaning device 1, and an alkaline detergent, pure water After the lower substrate 52a is cleaned using, for example, a drying process is performed at a predetermined temperature and time, for example, at 80 to 90 ° C. for 5 to 10 minutes.
The lower substrate 52a that has been cleaned and dried is conveyed to the lyophilic processing apparatus 2 by the belt conveyor A.

(S11)
Next, the cleaned and dried substrate surface is subjected to a lyophilic process (S11). That is, the substrate, for example, the lower substrate 52a, transported to the lyophilic processing device 2 by the belt conveyor A is taken into the lyophilic processing device 2, and the surface is lyophilicized by ultraviolet irradiation or plasma processing. By performing the lyophilic treatment, the wettability of the composition for forming a liquid crystal alignment film (the composition of the present invention) is further improved, and a liquid crystal alignment film that is more uniform, flat and excellent in adhesion can be formed on the substrate. it can.

(S12)
Next, the composition of the present invention is applied on the lyophilic substrate in S11 (S12). That is, first, a substrate, for example, the lower substrate 52a, transported to the droplet discharge device 3a by the belt conveyor A is placed on the table 28 and taken into the droplet discharge device 3a. In the droplet discharge device 3a, the composition of the present invention stored in the tank 30 is discharged through the nozzles of the nozzle forming surface 26, and the composition of the present invention is applied onto the lower substrate 52a. Thereby, the coating layer which consists of this invention composition is formed.

(S13)
Next, a process of temporarily drying the coating layer applied to the substrate is performed (S13). That is, the board | substrate conveyed to the drying apparatus 4 by the belt conveyor A, for example, the lower board | substrate 52a, is taken in in the drying apparatus 4, and temporary drying is performed at about 60-200 degreeC.
The lower substrate 52a on which the applied composition of the present invention (coating layer) has been temporarily dried is transferred to the belt conveyor A and conveyed to the baking apparatus 5 by the belt conveyor A.

(S14)
Next, the process of baking this invention composition by which temporary drying was performed is performed (S14). That is, the substrate conveyed to the baking apparatus 5 by the belt conveyor A, for example, the lower substrate 52a is taken into the baking apparatus 5 and is subjected to a process of baking to 180 to 250 ° C., for example.

In addition, when using the composition for liquid crystal aligning film formation (this invention composition) containing a polyamic acid, spin-drying | dehydration cyclization advances by this baking process and it may become a more imidized coating film. .
The film thickness of the coating film to be formed is usually 0.001 to 1 μm, preferably 0.005 to 0.5 μm.
As described above, as shown in FIG. 5, the lower substrate 52a on which the coating film 60a of the composition of the present invention is formed is obtained.
The lower substrate 52a is transferred to the belt conveyor A, and is conveyed to the rubbing device 6 by the belt conveyor A.

(S15)
Next, the rubbing process of the coating film 60a of the composition of the present invention formed on the substrate is performed (S15). In other words, a substrate conveyed to the rubbing device 6 by the belt conveyor A, for example, the lower substrate 52a is taken into the rubbing device 6 and rubbed in a certain direction with a roll wound with a cloth made of, for example, nylon, rayon, cotton or the like. Rubbing is performed. Thereby, as shown in FIG. 6, the alignment ability of the liquid crystal molecules is imparted to the coating film, and the liquid crystal alignment film 60 is formed.

  Further, a pretilt angle is obtained by partially irradiating a liquid crystal alignment film formed of the composition of the present invention with ultraviolet rays as disclosed in, for example, JP-A-6-222366 and JP-A-6-281937. A resist film is partially formed on the surface of the liquid crystal alignment film that has been subjected to rubbing treatment, as shown in Japanese Patent Application Laid-Open No. 5-107544, in a direction different from the previous rubbing treatment. The visibility characteristics of the liquid crystal display element can be improved by removing the resist film after the rubbing process and performing a process for changing the liquid crystal alignment ability of the liquid crystal alignment film.

(S16)
The lower substrate 52a on which the liquid crystal alignment film 60 is formed is transferred to the belt conveyor A, conveyed to the droplet discharge device 3b by the belt conveyor A, and taken into the droplet discharge device 3b. In the droplet discharge device 3b, as shown in FIGS. 7A and 7B, a seal layer forming solution is applied so as to surround the liquid crystal display region B on the rubbed liquid crystal alignment film 60. (S16). In FIG. 7, 59a is a coating film of the seal layer forming solution. 7A is a top view of the process, and FIG. 7B is a cross-sectional view of the process as viewed from the horizontal direction.

  Here, as the solution for forming the seal layer, a conventionally known adhesive can be used as an adhesive for joining the lower substrate and the upper substrate. For example, droplets containing an ionizing radiation curable resin (ionizing radiation curable resin composition), droplets containing a thermosetting resin (thermosetting resin composition), and the like are excellent in workability. From the above, the use of an ionizing radiation curable resin composition is preferred. The thermosetting resin composition and the ionizing radiation curable resin composition are not particularly limited, and conventionally known ones can be used.

(S17)
Next, the substrate coated with the seal layer forming solution is transferred to the belt conveyor A, and the substrate conveyed to the droplet discharge device 3c is taken into the droplet discharge device 3c by the belt conveyor A. In the droplet discharge device 3c, as shown in FIG. 8, the liquid crystal material 56 is applied to the liquid crystal layer forming region A surrounded by the coating film 59a of the sealing layer forming solution (S17).

Here, the liquid crystal material 56 is not particularly limited, and a conventionally known material can be used.
Liquid crystal modes include TN (Twisted Nematic), STN (Super Twisted Nematic), HAN (Hybrid Alignment Nematic), VA (Vertical Alignment), MVA (Multiple Alignment). OCB (Optical Compensated Bend) type and the like.

The liquid crystal material may contain a spacer. The spacer is a member for keeping the thickness (cell gap) of the liquid crystal layer constant. The spacer material is not particularly limited, and conventionally known materials can be used.
In addition to the liquid crystal material, a functional liquid containing a spacer may be applied before or after the liquid crystal material is applied.

(S18)
Next, as shown in FIG. 9A, the substrate on which the liquid crystal material 56 has been applied is conveyed into a vacuum chamber 90a of the bonding apparatus, and the inside of the chamber 9a is evacuated and then sucked onto the lower surface plate 80a. Fixed. On the other hand, the substrate (upper substrate) 52b on which the color filter 62, the black matrix 64, the overcoat film 66, the common electrode 68, and the liquid crystal alignment film 70 (these are omitted) is placed on the upper surface plate 80b. The lower substrate 52a and the upper substrate 52b are bonded together by sucking and fixing (S18).

  Specifically, the alignment when the lower substrate 52a and the upper substrate 52b are bonded can be performed while recognizing the alignment marks provided in advance on the lower substrate 52a and the upper substrate 52b with a camera. At this time, in order to increase alignment accuracy, it is preferable to perform alignment by setting the distance between the lower substrate 52a and the upper substrate 52b to about 0.2 to 0.5 mm.

(S19)
Next, a curing process is performed on the laminate obtained by bonding the lower substrate 52a and the upper substrate 52b. The curing process is performed using a curing device (S19). Examples of the curing device include an ionizing radiation irradiation device and a heating device. In this embodiment, an ultraviolet irradiation device 82 is used. That is, as shown in FIG. 9B, ultraviolet rays are irradiated by the ultraviolet irradiation device 82 to cure the seal layer 59a.
Next, the reduced pressure in the chamber 9a is released to atmospheric pressure, and the adsorption of the lower substrate 52a and the upper substrate 52b is released.

  Thereafter, a polarizing plate is disposed on the outer surface of the liquid crystal cell, that is, the other surface side of each substrate constituting the liquid crystal cell, and the polarization direction thereof coincides with the rubbing direction of the liquid crystal alignment film formed on one surface of the substrate. Paste them so that they are orthogonal. Here, as a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film called an H film that absorbs iodine while stretching and aligning polyvinyl alcohol is sandwiched between cellulose acetate protective films or H A polarizing plate made of the film itself can be mentioned.

As described above, the liquid crystal display device shown in FIG. 3 can be manufactured.
Since the obtained liquid crystal display device has the liquid crystal alignment film formed by applying the composition of the present invention by the droplet discharge device 3a, the liquid crystal display device becomes a high quality and low cost liquid crystal display device.

In this embodiment, the liquid crystal alignment film is formed by a method of performing a rubbing process in S15. For example, a method of irradiating polarized radiation disclosed in Japanese Patent Application Laid-Open No. 2004-163646. The liquid crystal alignment ability can also be given by the above.
In this embodiment, in S17, a liquid crystal layer is formed by applying a liquid crystal material using the droplet discharge device 3c. However, two substrates on which a liquid crystal alignment film is formed are produced. Two substrates are arranged opposite to each other with a gap (cell gap) so that the rubbing directions in the respective liquid crystal alignment films are orthogonal or antiparallel, and the peripheral portions of the two substrates are bonded using a sealant. In addition, liquid crystal may be injected and filled in the cell gap defined by the substrate surface and the sealing agent, and the injection hole may be sealed to form a liquid crystal layer.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
[VA type composition]
First, examples of the composition for forming a liquid crystal alignment film when the display method of the liquid crystal display device is the VA method will be described.

(Examples 1-6)
As the high boiling point organic solvent A1 in the first organic solvent A, one of ethylene carbonate (ethylene carbonate), propylene carbonate (propylene carbonate), and butylene carbonate (butylene carbonate) was used. In Examples 2 to 6, N-methyl-2-pyrrolidone or N, N′-dimethyl-2-imidazolidinone was used as the low boiling point organic solvent A2 in the first organic solvent A. Furthermore, as the second organic solvent B, one of diethylene glycol ethyl methyl ether, ethylene glycol monobutyl ether, and diethylene glycol diethyl ether was used. And these were mixed in the ratio shown in following Table 1, and the mixed solvent was obtained.
(Comparative Examples 1-4)
As the first organic solvent A, one or more of γ-butyrolactone, N-methyl-2-pyrrolidone, N, N′-dimethyl-2-imidazolidinone, and propylene carbonate (propylene carbonate) were used. In addition, ethylene glycol monobutyl ether was used as the second organic solvent B. And these were mixed in the ratio shown in following Table 1, and the mixed solvent was obtained.

  In each of the mixed solvents thus obtained (Examples 1 to 6, Comparative Examples 1 to 4), polyimide (AL-60601 [for VA] manufactured by JSR) was added at a solid content concentration of 3.5 wt. %, And the liquid crystal alignment film forming compositions of Examples 1 to 6 and Comparative Examples 1 to 4 were respectively prepared.

The obtained composition for forming a liquid crystal alignment film was applied using a droplet discharge device equipped with a multihead so that the dry film thickness was 100 nm from the multihead onto the ITO substrate. Membrane was performed.
When the obtained liquid crystal alignment film is visually observed for the presence or absence of joint unevenness (straight unevenness) due to the connection part between the heads, when the joint unevenness is not observed, ○, when the joint unevenness is slightly observed Was evaluated as △, and when a lot of connecting unevenness was observed, it was evaluated as ×. Also, it was confirmed whether or not the film could be formed satisfactorily, and when it could be performed satisfactorily, it was evaluated as ◯.

From the results shown in Table 1, as the high-boiling organic solvent A1 in the first organic solvent A, ethylene carbonate (ethylene carbonate), propylene carbonate (propylene carbonate), and butylene carbonate (butylene carbonate) are mixed in the entire mixed solvent. In Examples 1 to 6 formulated so as to be 20% by weight or more, no connection unevenness due to the connection portion between the heads was observed. This is because the composition spreads well on the substrate even when the coating layer is dried, and the solid content (solute) is uniformly distributed on the substrate, thereby further flattening the coating layer. it is conceivable that.
Moreover, in any of these Examples 1 to 6, film formation could be performed satisfactorily.
On the other hand, in Comparative Examples 1 to 4 in which the mixing ratio of the high-boiling organic solvent A1 in the entire mixed solvent was less than 20% by weight, connection unevenness due to the connecting portion between the heads was observed.

[Composition for IPS system]
Next, examples of the composition for forming a liquid crystal alignment film when the display method of the liquid crystal display device is the IPS method will be described.

(Examples 1-6)
As the high boiling point organic solvent A1 in the first organic solvent A, one of ethylene carbonate (ethylene carbonate), propylene carbonate (propylene carbonate), and butylene carbonate (butylene carbonate) was used. In addition, as the low boiling point organic solvent A2 in the first organic solvent A, one kind or plural kinds of γ-butyrolactone, N-methyl-2-pyrrolidone, and N, N′-dimethyl-2-imidazolidinone were used. Furthermore, as the second organic solvent B, one of diethylene glycol ethyl methyl ether, ethylene glycol monobutyl ether, and diethylene glycol diethyl ether was used. And these were mixed in the ratio shown in following Table 2, and the mixed solvent was obtained.
(Comparative Examples 1-5)
As the first organic solvent A, one or more of γ-butyrolactone, N-methyl-2-pyrrolidone, N, N′-dimethyl-2-imidazolidinone, and propylene carbonate (propylene carbonate) were used. As the second organic solvent B, one of diethylene glycol ethyl methyl ether, ethylene glycol monobutyl ether, and diethylene glycol diethyl ether was used. And these were mixed in the ratio shown in following Table 2, and the mixed solvent was obtained.

  In each of the mixed solvents thus obtained (Examples 1 to 6, Comparative Examples 1 to 5), polyimide (AL-16470 manufactured by JSR Corporation [for IPS]) and a solid content concentration of 3.5 wt. %, And the liquid crystal alignment film forming compositions of Examples 1 to 6 and Comparative Examples 1 to 5 were respectively prepared.

The obtained composition for forming a liquid crystal alignment film was applied using a droplet discharge device equipped with a multihead so that the dry film thickness was 100 nm from the multihead onto the ITO substrate. Membrane was performed.
When the obtained liquid crystal alignment film is visually observed for the presence or absence of joint unevenness (straight unevenness) due to the connection part between the heads, when the joint unevenness is not observed, ○, when the joint unevenness is slightly observed Was evaluated as △, and when a lot of connecting unevenness was observed, it was evaluated as ×. Also, it was confirmed whether or not the film could be formed satisfactorily, and when it could be performed satisfactorily, it was evaluated as ◯.

From the results shown in Table 2, as the high boiling point organic solvent A1 in the first organic solvent A, ethylene carbonate (ethylene carbonate), propylene carbonate (propylene carbonate), butylene carbonate (butylene carbonate) are mixed in the entire mixed solvent. In Examples 1 to 6 formulated so as to be 20% by weight or more, no connection unevenness due to the connection portion between the heads was observed. This is because the composition spreads well on the substrate even when the coating layer is dried, and the solid content (solute) is uniformly distributed on the substrate, thereby further flattening the coating layer. it is conceivable that.
Moreover, in any of these Examples 1 to 6, film formation could be performed satisfactorily.
On the other hand, in Comparative Examples 1 to 4 in which the mixing ratio of the high-boiling organic solvent A1 in the entire mixed solvent was less than 20% by weight, connection unevenness due to the connecting portion between the heads was observed.

It is a figure which shows an example of the liquid crystal display device manufacturing line which concerns on embodiment. 1 is a schematic view of an ink jet type ejection device according to an embodiment. It is a sectional side view which shows schematic structure of the liquid crystal display device which concerns on embodiment. It is a flowchart of the manufacturing method of the liquid crystal display device which concerns on embodiment. It is manufacturing process explanatory drawing of the liquid crystal display device which concerns on embodiment. It is manufacturing process explanatory drawing of the liquid crystal display device which concerns on embodiment. It is manufacturing process explanatory drawing of the liquid crystal display device which concerns on embodiment. It is manufacturing process explanatory drawing of the liquid crystal display device which concerns on embodiment. It is manufacturing process explanatory drawing of the liquid crystal display device which concerns on embodiment.

Explanation of symbols

  I ... Liquid crystal display device production line, 3a, 3b, 3c ... Discharge device, 22 ... Inkjet head, 24 ... Head body, 34 ... Discharge product (liquid crystal alignment film forming composition), 50 ... Liquid crystal display device, 56 ... Liquid crystal Layer, 60, 70 ... Liquid crystal alignment film, A ... Liquid crystal layer forming region

Claims (8)

A composition for forming a liquid crystal alignment film used when forming a liquid crystal alignment film by a droplet discharge method,
A mixed solvent containing a first organic solvent A having a surface tension of 37 mN / m or more and a second organic solvent B having a surface tension of less than 32 mN / m, and a liquid crystal alignment film forming material dissolved in the mixed solvent; , Containing
The first organic solvent A and the second organic solvent B are each composed of a single type or a plurality of types of organic solvents,
The first organic solvent A includes a high-boiling organic solvent A1 having a boiling point of 235 ° C. or higher and a viscosity at 20 ° C. of 4 mPa · s or lower as an organic solvent constituting the first organic solvent A. ,
The composition for forming a liquid crystal alignment film, wherein the high-boiling organic solvent A1 has a mixing ratio of 20% by weight or more in the entire mixed solvent.   2. The composition for forming a liquid crystal alignment film according to claim 1, wherein a mixing ratio of the second organic solvent B in the entire mixed solvent is 3 wt% or more and 50 wt% or less.   The composition for forming a liquid crystal alignment film according to claim 1 or 2, wherein the high-boiling organic solvent A1 contains at least one of ethylene carbonate, propylene carbonate, and butylene carbonate.   The first organic solvent A is a low-boiling organic solvent A2 other than the high-boiling organic solvent A1, and includes N-methyl-2-pyrrolidone, γ-butyrolactone, N, N′-dimethyl-2-imidazolidinone. The composition for forming a liquid crystal alignment film according to claim 3, comprising at least one kind.   5. The composition for forming a liquid crystal alignment film according to claim 3, wherein the second organic solvent B contains at least one of diethylene glycol ethyl methyl ether, ethylene glycol monobutyl ether, and diethylene glycol diethyl ether.   The solid content concentration is 1% by weight to 10% by weight, the viscosity is adjusted to 3 mPa · s to 20 mPa · s, and the surface tension is adjusted to 30 mN / m to 45 mN / m. The composition for liquid crystal aligning film formation as described in any one of 1-5. The material for forming a liquid crystal alignment film has the following formula (I)

(Wherein P ¹ is a tetravalent organic group, Q ¹ represents a divalent organic group), and the following formula (II)

(Wherein P ² is a tetravalent organic group and Q ² represents a divalent organic group), and is a polymer having at least one selected from repeating units represented by Item 7. The composition for forming a liquid crystal alignment film according to any one of Items 1 to 6.   A liquid crystal display device comprising a step of applying the composition for forming a liquid crystal alignment film according to claim 1 to a substrate surface by a droplet discharge method to form a liquid crystal alignment film. Manufacturing method.

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