TW202311507A - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

The present invention relates to a liquid crystal alignment agent which contains: (A) a polymer obtained from a diamine component containing a diamine represented in formula (1), and an acid componentcontaining a cyclobutane tetracarboxylic dianhydride represented in formula (2-1) and/or a cyclobutane tetracarboxylic acid diester represented in formula (2-2) (in formula (2-2), the Rs are independently alkyl groups with 1-5 carbons.); and (B) an organic solvent. Thus, it is possible to provide a substrate with a liquid crystal alignment film for a lateral electric field drive liquid crystal display element, which is highly efficiently imparted with alignment control ability and which has excellent burn-in characteristics, and to provide a lateral electric field drive liquid crystal displayelement having said substrate.

Description

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

The invention relates to a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element for manufacturing a liquid crystal display element with excellent burning properties.

Liquid crystal display elements are known as light-weight, thin and low-power-consumption display devices, and have been used in large-scale televisions and the like in recent years, and have been significantly developed. The liquid crystal display element is constituted, for example, by sandwiching a liquid crystal layer between a pair of transparent substrates provided with electrodes. In addition, in a liquid crystal display element, an organic film made of an organic material is used as a liquid crystal alignment film so that liquid crystals may be in a desired alignment state between substrates.

That is, the liquid crystal alignment film is a constituent member of the liquid crystal display element, and is formed on the surface of the substrates sandwiching the liquid crystal and in contact with the liquid crystal, and plays a role of aligning the liquid crystal in a certain direction between the substrates. Moreover, in addition to the function of aligning the liquid crystal in a certain direction such as a direction parallel to the substrate, the liquid crystal alignment film also requires the function of controlling the pretilt angle of the liquid crystal. The ability to control the alignment of liquid crystals in such a liquid crystal alignment film (hereinafter referred to as alignment control ability) can be imparted by performing an alignment treatment on the organic film constituting the liquid crystal alignment film.

A rubbing method has been conventionally known as an alignment treatment method for a liquid crystal alignment film for imparting alignment control capability. The so-called rubbing method refers to the organic film of polyvinyl alcohol or polyamide or polyimide on the substrate, using cloth such as cotton, nylon, polyester, etc. to wipe (rub) its surface in a certain direction to make the liquid crystal A method of aligning in the wiping direction (rubbing direction). This rubbing method can easily realize a relatively stable alignment state of liquid crystals, so it is used in the conventional manufacturing process of liquid crystal display elements. In addition, as an organic film used in a liquid crystal alignment film, a polyimide-based organic film excellent in reliability such as heat resistance or in electrical characteristics is mainly selected.

However, the rubbing method of rubbing the surface of the liquid crystal alignment film made of polyimide or the like has the problem of generating dust or static electricity. Moreover, due to the high-definition of liquid crystal display elements in recent years, or the unevenness caused by the electrodes on the corresponding substrate or the active switching elements for liquid crystal driving, it is sometimes impossible to wipe the surface of the liquid crystal alignment film evenly with a cloth, and Uniform alignment of liquid crystals cannot be achieved. Therefore, as another alignment treatment method of a liquid crystal alignment film without rubbing, the photo-alignment method is being actively studied.

There are various methods in the photo-alignment method, but anisotropy is formed in the organic film constituting the liquid crystal alignment film by linearly polarized light or collimated light, and the liquid crystal is aligned according to the anisotropy. As a main photo-alignment method, a decomposition-type photo-alignment method is known. For example, polarized ultraviolet rays are irradiated to a polyimide film, and the polarization direction dependence of ultraviolet absorption of the molecular structure is used to cause anisotropic decomposition. Moreover, the liquid crystal is aligned by the polyimide which remains undecomposed (for example, refer patent document 1).

In addition, photo-crosslinking or photo-isomerization photo-alignment methods are also known. For example, polyvinyl cinnamate is used to irradiate polarized ultraviolet light to cause a dimerization reaction (crosslinking reaction) in the double bond portion of the two side chains parallel to the polarized light. Also, the liquid crystal is aligned in a direction perpendicular to the polarization direction (for example, refer to Non-Patent Document 1). In addition, when using a side chain type polymer having azobenzene in the side chain, irradiate polarized ultraviolet rays to cause an isomerization reaction in the azobenzene part of the side chain parallel to the polarized light, so that the liquid crystal is oriented in the direction of the polarized light. Orthogonal directions are aligned (for example, refer to Non-Patent Document 2).

Also, as a photo-alignment film for improving image sticking characteristics caused by AC driving, it is known to adopt polyamic acid produced by using diamine containing cyclobutane ring and imide group (for example, refer to the patent document 3).

As in the above examples, the alignment treatment method of the liquid crystal alignment film by the photo-alignment method does not require rubbing, and there is no risk of dust or static electricity. In addition, alignment treatment can be applied even to the substrate of the liquid crystal display element with unevenness on the surface, and it will become a method for alignment treatment of liquid crystal alignment films suitable for industrial production processes. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 3893659 [Patent Document 2] Japanese Patent No. 3612832 [Patent Document 3] Korean Patent Application Publication No. 10-2016-0142614 [Non-patent literature]

[Non-Patent Document 1] M. Shadt et al., Jpn. J. Appl. Phys. 31, 2155(1992). [Non-Patent Document 2] K. Ichimura et al., Chem. Rev. 100, 1847(2000).

[Problem to be Solved by the Invention]

As described above, compared with the rubbing method conventionally used industrially as an alignment treatment method for liquid crystal display elements, the photo-alignment method does not require a rubbing step, and thus has a great advantage. In addition, compared with the rubbing method in which the alignment control ability is substantially constant by rubbing, the photo-alignment method can control the alignment control ability by changing the light irradiation amount of polarized light. However, in the photo-alignment method, in order to achieve the same degree of alignment control as that achieved by the rubbing method, a large amount of polarized light irradiation may be required, or stable liquid crystal alignment may not be achieved.

For example, in the decomposition-type photoalignment method described in the above-mentioned Patent Document 1, it is necessary to irradiate the polyimide film with ultraviolet light from a high-pressure mercury lamp with an output of 500 W for 60 minutes, which requires a long time and a large amount of ultraviolet irradiation. . Moreover, even in the case of a dimerization type or a photoisomerization type photoalignment method, a large amount of ultraviolet irradiation of about several J (joules) to several tens of J may be required. Furthermore, in the case of photo-crosslinking or photo-isomerization photo-alignment methods, since the thermal stability or light stability of liquid crystal alignment is poor, when used as a liquid crystal display element, poor alignment will occur. Or show problems like burning. In particular, in transverse electric field driven liquid crystal display elements, since the liquid crystal molecules are switched in-plane, misalignment of the liquid crystal after liquid crystal driving is likely to occur, and display burn-in caused by AC driving becomes a major problem. .

Therefore, in the photo-alignment method, it is required to realize high-efficiency alignment treatment or stable liquid crystal alignment, and a liquid crystal alignment film capable of efficiently imparting high alignment control ability to the liquid crystal alignment film and a manufacturing method thereof are required.

The object of the present invention is to provide a substrate having a liquid crystal alignment film for a transverse electric field drive type liquid crystal display element that imparts alignment control ability with high efficiency and is excellent in burning characteristics, a transverse electric field drive type liquid crystal display element having the substrate, and a manufacturing method thereof . [Means to solve the problem]

The inventors of the present invention have found the following inventions as a result of intensive research to achieve the above objects.

1. A liquid crystal alignment agent comprising: (A) a diamine component comprising a diamine represented by the following formula (1), and a cyclobutane selected from the group consisting of a diamine represented by the following formula (2-1) A polymer composed of tetracarboxylic dianhydride and at least one acid component of cyclobutane tetracarboxylic diester represented by the following formula (2-2), and (B) an organic solvent,

(In the formula (2-2), R is each independently an alkyl group having 1 to 5 carbon atoms).

2. The liquid crystal alignment agent according to the above 1, wherein the polymer is at least one selected from the group consisting of polyimide precursors and polyimides thereof. 3. The liquid crystal alignment agent according to any one of the above-mentioned 1 or 2, wherein R in the above-mentioned formula (2-2) are all methyl groups. 4. The liquid crystal alignment agent described in any one of the above 1 to 3, wherein the aforementioned polymer is represented by the following formula (3),

(In formula (3), X is a _tetravalent organic group derived from tetracarboxylic acid derivatives and said tetracarboxylic acid derivatives include at least one of the above formulas (2-1) and (2-2) One structure, Y ₁ is a divalent organic group derived from diamine and the diamine contains the structure of formula (1), R ₁₁ is a hydrogen atom or an alkyl group with 1 to 5 carbons). 5. The liquid crystal alignment agent according to the above 4, wherein the polymer having the structural unit represented by the aforementioned formula (3) is contained at 10 mol% or more relative to all polymers contained in the liquid crystal alignment agent. 6. A liquid crystal alignment film for a transverse electric field driven liquid crystal display element, which is obtained by using the liquid crystal alignment agent described in any one of the above-mentioned 1-5. 7. A substrate comprising the liquid crystal alignment film for a transverse electric field driven liquid crystal display element as described in 6 above. 8. A liquid crystal display element driven by a transverse electric field, comprising the substrate as described in 7 above. [Effect of the invention]

According to the present invention, it is possible to provide a substrate having a liquid crystal alignment film for a transverse electric field drive type liquid crystal display element that imparts alignment control ability with high efficiency and has excellent burning characteristics, and a transverse electric field drive type liquid crystal display element having the substrate. The transverse electric field drive type liquid crystal display element manufactured by the method of the present invention is endowed with alignment control ability with high efficiency, so even if it is driven continuously for a long time, the display characteristics will not be damaged.

The polymer composition used in the production method of the present invention is a photosensitive main chain type polymer (hereinafter, also referred to as the main chain type polymer) capable of exhibiting self-organization ability, so the aforementioned polymer composition is used The obtained coating film is a film having a photosensitive main chain type polymer capable of exhibiting self-organization ability. The coating film was not subjected to rubbing treatment, but was subjected to alignment treatment by polarized light irradiation. Moreover, after polarized light irradiation, the process of heating this main chain type polymer film becomes the coating film (henceforth also referred to as a liquid crystal alignment film) provided with the alignment control ability. At this time, the slight anisotropy exhibited by the polarized light irradiation becomes the driving force, so the main chain polymer itself is efficiently re-aligned through self-organization. As a result, a highly efficient alignment treatment was realized as a liquid crystal alignment film, and a liquid crystal alignment film provided with high alignment control ability was obtained.

Moreover, the liquid crystal alignment film formed by the polymer composition of the present invention has excellent film strength. Accordingly, when used as a liquid crystal display element, even if thinning (slimming) chemical polishing is performed, it is difficult to cause grinding or peeling of the liquid crystal alignment film.

[Best Mode for Carrying Out the Invention]

Hereinafter, embodiments of the present invention will be described in detail. The liquid crystal alignment agent of the present invention contains a diamine component comprising a diamine represented by the above formula (1), and a cyclobutanetetracarboxylic dianhydride represented by the above formula (2-1), and a polymer (hereinafter also referred to as a specific polymer or a main chain type polymer) composed of at least one acid component of the cyclobutane tetracarboxylic acid diester represented by the above formula (2-2) Liquid crystal alignment agent. Each condition will be described in detail below.

The liquid crystal alignment agent of the present invention is a liquid crystal alignment agent containing the following polymer and an organic solvent, and the polymer is composed of diamine represented by the above formula (1) (also referred to as specific diamine), and the diamine component comprising cyclobutane tetracarboxylic dianhydride (also referred to as specific tetracarboxylic dianhydride in the present invention) represented by the above formula (2-1), and the above formula (2 -2) A polymer obtained by comprising at least one acid component of the cyclobutane tetracarboxylic acid diesters (also referred to as specific tetracarboxylic acid diesters in the present invention).

＜Polymer＞ The polymer used in the liquid crystal alignment agent of the present invention is composed of a diamine component comprising a diamine represented by the above formula (1), and a cyclobutanetetracarboxylic compound selected from the above formula (2-1). The obtained polymer constituted by the acid dianhydride and at least one acid component of the cyclobutane tetracarboxylic diester represented by the above formula (2-2). As specific examples, polyamic acid, polyamic acid ester, polyimide, polyurea, polyamide, etc. can be mentioned, but in terms of the use as a liquid crystal alignment agent, it is selected from the following: At least one of a polyimide precursor of the structural unit represented by the above-mentioned formula (3) and a polyimide which is an imide thereof is preferable. In the heating step after polarized light irradiation, the polyimide precursor is more preferable in terms of higher order re-alignment due to more freely rotating sites in the polymer.

In the above formula (3), X is _{a tetravalent} organic group derived from tetracarboxylic acid derivatives and the tetracarboxylic acid derivatives include at least one of the above formulas (2-1) and (2-2). In one structure, Y ₁ is a divalent organic group derived from a diamine and the diamine contains the structure of formula (1), and R ₁₁ is a hydrogen atom or an alkyl group having 1 to 5 carbons. From the viewpoint of easiness of imidization by heating, R ₁₁ is preferably a hydrogen atom, a methyl group or an ethyl group, and more preferably a hydrogen atom.

<Tetracarboxylic acid derivatives> X ₁ is a tetravalent organic group derived from tetracarboxylic acid derivatives and said tetracarboxylic acid derivatives contain at least 1 type of construction.

(In formula (2-2), R is independently an alkyl group with 1 to 5 carbons)

In the above-mentioned structure, from the viewpoint of easiness of imidization by heating, R is preferably a methyl group.

<Diamine> In formula (3), Y ₁ is a structure in which two amino groups were removed from the diamine represented by the aforementioned formula (1).

＜Polymers (other structural units)＞ The polyimide precursor comprising the structural unit represented by the formula (3) may contain a structural unit selected from the following formula (4) and as its amide within the scope of not impairing the effect of the present invention At least one kind of imide polyimide.

In formula (4), X ₂ is a tetravalent organic group derived from tetracarboxylic acid derivatives, Y ₂ is a divalent organic group derived from diamine, and R ₁₂ is defined as R ₁₁ of the aforementioned formula (3) as Similarly, _R22 represents a hydrogen atom or an alkyl group having 1 to 4 carbons. Also, at least one of the two R ₂₂ is preferably a hydrogen atom. X ₂ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and its structure is not particularly limited. In addition, the _X2 in the polyimide precursor depends on the solubility of the polymer to the solvent or the coatability of the liquid crystal alignment agent, the alignment of the liquid crystal when it is made into a liquid crystal alignment film, the voltage retention rate, and the storage capacity. It can be appropriately selected according to the degree of required characteristics such as electric charge, and it may be one type, or two or more types may be mixed in the same polymer.

If it is necessary to show specific examples of _X2 , the structures of formulas (X-1) to (X-46) disclosed in Items 13 to 14 of International Publication No. 2015/119168 can be cited. .

The following shows preferred _X2 structures, but the present invention is not limited thereto.

In addition, Y ₂ in the polyimide precursor is a divalent organic group derived from diamine, and its structure is not particularly limited. In addition, _Y2 is based on the solubility of the polymer to the solvent or the applicability of the liquid crystal alignment agent, the alignment of the liquid crystal when it is made into a liquid crystal alignment film, the degree of voltage retention, and the required characteristics of the stored charge. For proper selection, one type may be present in the same polymer, or two or more types may be present in admixture.

If it is necessary to show specific examples of _Y2 , the structure of the formula (2) disclosed in item 4 of International Publication No. 2015/119168, and the formulas disclosed in items 8 to 12 ( Structures of Y-1)～(Y-97), (Y-101)～(Y-118); two amine groups are removed from formula (2) as disclosed in Item 6 of International Publication No. 2013/008906 The divalent organic group; the divalent organic group that removes two amine groups from the formula (1) disclosed in item 8 of the International Publication Publication No. 2015/122413; the eighth item of the International Publication Publication No. 2015/060360 The structure of the disclosed formula (3); the divalent organic group that removes two amine groups from the formula (1) described in item 8 of Japanese Patent Application Laid-Open No. 2012-173514; International Publication No. 2010-050523 Item 9 of the publication discloses a divalent organic group obtained by removing two amine groups from formulas (A) to (F), and the like.

As a preferable structure of _Y2 , the structure of following formula (5) is mentioned.

In formula (5), R ³² is a single bond or a divalent organic group, preferably a single bond. R ³³ is a structure represented by -(CH ₂ ) _n -. n is an integer of 2-10, preferably 3-7. Also, any -CH ₂ - can be substituted with an ether, ester, amide, urea, or urethane bond under the condition that they are not adjacent to each other. R ³⁴ is a single bond or a divalent organic group. Any hydrogen atom on the benzene ring can be replaced by a monovalent organic group, preferably a fluorine atom or a methyl group.

As a structure represented by formula (5), specifically, the following structure can be mentioned, However, It is not limited to these.

Among them, the diamine represented by the following formula (10) is preferable as the diamine that gives the structure of Y ₂ .

(In the formula (10), L is a divalent organic group containing an alkylene group and any bonded carbon number of 2 or more selected from an ether bond and an ester bond, and R ₁ and R ₂ are independently monovalent organic groups. base, p1 and p2 are independently integers from 0 to 4, p is 0 or 1, and q1 and q2 are independently 1 or 2).

Examples of the one-valent organic group here include alkyl, alkenyl, alkoxy, fluoroalkyl, fluoroalkenyl, or fluoroalkoxy having a carbon number of 1 to 10 (preferably 1 to 3). base. Among them, methyl is preferred as the monovalent organic group.

Examples of the divalent organic group include a group consisting of an alkylene group and an ether bond, a group consisting of an alkylene group and an ester bond, and an alkylene group in which some or all of the hydrogen atoms are substituted with halogens and an ether bond. A group constituted, or a group constituted by an alkylene group in which a part or all of hydrogen atoms are substituted with halogen and an ester bond. Among them, as the divalent organic group, a group composed of an alkylene group and an ether bond is preferable. The carbon number is preferably from 2 to 20, and more preferably from 2 to 10.

In addition, among the number of atoms of L, if the total number of carbon atoms and oxygen atoms participating in the length of the main chain is an even number, the linearity of the obtained polymer becomes high. As a result, by adding In the heating step after irradiation of polarized light, it is preferable to obtain a liquid crystal alignment film provided with high alignment control ability because it can be re-aligned with a higher order. Still, the so-called sum of the number of carbon atoms and oxygen atoms participating in the length of the main chain means that the number of each methylene group in the main chain is set to 1, the number of each ether bond is set to 1, and each The total when the number of ester bonds is 2.

As p1 and p2, 0 is preferable in terms of less steric hindrance, easy overlapping of phenyl groups, and higher order rearrangement.

As p, the one having an alkylene group functioning as a freely rotating site is preferably 1 in terms of higher-order rearrangement.

Among the diamines of the above-mentioned formula (10), specific examples of diamines in which p is 1 can be illustrated as follows, but are not limited thereto.

Here, when the total of r, t, and u is an even number such as 2, 4, 6, 8, and 10, the linearity of the obtained polymer becomes high. In the heating step, re-alignment is performed with a higher order, so that a liquid crystal alignment film endowed with high alignment control ability can be obtained. For the above reasons, s is preferably an odd number of 1, 3, 5, etc.

Among the diamines represented by the above-mentioned formula (10), p-phenylenediamine is mentioned as a specific example of the diamine in which p is 0.

If the polyimide precursor comprising the structural unit represented by formula (3) contains the structural unit represented by formula (4) simultaneously, in terms of the orientation of the obtained liquid crystal alignment film, it is relatively In the total of formula (3) and formula (4), the structural unit represented by formula (4) is preferably 10 mol % to 90 mol %, and more preferably 20 mol % to 80 mol % , preferably 30 mol% to 70 mol%.

The molecular weight of the polyimide precursor used in the present invention is preferably 2,000-500,000 in weight average molecular weight, more preferably 5,000-300,000, more preferably 10,000-100,000.

Examples of the polyimide used in the present invention include polyimide obtained by subjecting the aforementioned polyimide precursor to ring closure. In this polyimide, the ring-closing rate (also referred to as the imidization rate) of the amide acid group is not necessarily 100%, and can be adjusted arbitrarily according to the application or purpose. For the polymer of the present invention, from the viewpoint of liquid crystal alignment, the imidization rate is preferably 0-70%, and more preferably 0-50%. In addition, the imidization ratio here is the imidization ratio calculated by removing the imide structure derived from the diamine represented by formula (1). As a method for imidizing a polyimide precursor, thermal imidization in which a solution of a polyimide precursor is directly heated, or adding a catalyst to a solution of a polyimide precursor Catalytic imidization.

＜Liquid crystal alignment agent＞ The liquid crystal alignment agent of the present invention contains a diamine component comprising a diamine represented by the above formula (1), and a cyclobutanetetracarboxylic dianhydride represented by the above formula (2-1), and the above-mentioned Polymer (specific polymer) obtained by constituting at least one acid component of cyclobutane tetracarboxylic acid diester represented by formula (2-2), as long as it is within the range where the effect described in the present invention can be exhibited , can contain two or more specific polymers with different structures. Moreover, other than a specific polymer, that is, the polymer which does not have the divalent group derived from the diamine represented by formula (1) may be contained. Examples of other types of polymers include polyamic acid, polyimide, polyamide ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivatives, polycondensate Aldehydes, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivatives, poly(meth)acrylates, and the like. When the liquid crystal alignment agent of the present invention contains other polymers, the ratio of the specific polymer to the total polymer component is preferably 10% by mass or more, and an example thereof is 10 to 100% by mass.

A liquid crystal alignment agent is used for producing a liquid crystal alignment film, and generally takes the form of a coating liquid from the viewpoint of forming a uniform thin film. Even the liquid crystal alignment agent of the present invention is preferably a coating solution containing the aforementioned polymer component and an organic solvent for dissolving the polymer component. At this time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed according to the thickness of the coating film to be formed. From the point of forming a uniform and defect-free coating film, it is preferably 1% by mass or more, and from the point of storage stability of the solution, it is preferably 10% by mass or less. A particularly preferable concentration of the polymer is 2 to 8% by mass.

The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as the polymer component can be dissolved uniformly. When specific examples are given, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2- Pyrrolidone, dimethylsulfene, γ-butyrolactone, 1,3-dimethyl-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, etc. Among them, it is preferable to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone.

In addition, the organic solvent contained in the liquid crystal alignment agent, in addition to the above-mentioned solvents, generally uses a mixed solvent, and the mixed solvent is used in combination to improve the coatability or coating film when coating the liquid crystal alignment agent. Therefore, even the liquid crystal alignment agent of the present invention can suitably use such a mixed solvent. Specific examples of organic solvents that can be used in combination are given below, but are not limited to these examples.

Examples include ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1 -butanol, isoamyl alcohol, tert-pentanol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol Alcohol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol , 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butane Diol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2- Ethyl-1,3-hexanediol, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl base ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl Diethyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, Ethyl carbonate, 2-(methoxymethoxy)ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2-(hexyloxy)ethanol, Furfuryl alcohol, diethylene glycol, propylene glycol, propylene glycol monobutyl ether, 1-(butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol mono Ethyl ether, Dipropylene glycol dimethyl ether, Tripropylene glycol monomethyl ether, Ethylene glycol monomethyl ether acetate, Ethylene glycol monoethyl ether acetate, Ethylene glycol monobutyl ether acetate , ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethyl ether oxy) ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate ester, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate Ethyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate ester, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isopentyl lactate, solvents represented by the following formulas [D-1] to [D-3], and the like.

In formula [D-1], D ¹ represents an alkyl group with 1 to 3 carbon atoms, in formula [D-2], D ² represents an alkyl group with 1 to 3 carbon atoms, and in formula [D-3], D ³ represents an alkyl group having 1 to 4 carbon atoms.

The kind and content of such a solvent can be suitably selected according to the coating apparatus of a liquid crystal alignment agent, coating conditions, coating environment, etc.

The liquid crystal alignment agent of the present invention may additionally contain components other than the polymer component and the organic solvent within the range not impairing the effect of the present invention. Examples of such additional components include adhesion aids for improving the adhesion between the liquid crystal alignment film and the substrate or the adhesion between the liquid crystal alignment film and the sealing material, and crosslinking agents for increasing the strength of the liquid crystal alignment film. agent, dielectric or conductive substance used to adjust the dielectric rate or resistance of the liquid crystal alignment film, etc. Specific examples of these additional components include various components disclosed in well-known documents related to liquid crystal alignment agents, but if one example must be shown, it can be cited on page 53 of the publication No. 2015/060357 [ 0105] to the ingredients disclosed in [0116] on page 55, etc.

<Manufacturing method of substrate with liquid crystal alignment film> and <Manufacturing method of liquid crystal display element> The manufacturing method of the substrate having the liquid crystal alignment film of the present invention has the following steps: [I] After coating the polymer composition on the substrate with the conductive film for transverse electric field driving, drying and forming a coating film, the polymer composition contains: (A) consisting of the above formula (1 ), a diamine component comprising a diamine represented by the above formula (2-1), and a cyclobutane tetracarboxylic dianhydride represented by the above formula (2-2) A polymer obtained by at least one acid component in the acid diester, and (B) an organic solvent; [II] a step of irradiating polarized ultraviolet rays to the coating film obtained in [I]; and [III] A step of heating the coating film obtained in [II]. Through the above steps, a liquid crystal alignment film for a transverse electric field driven liquid crystal display element endowed with alignment control capability can be obtained, and a substrate having the liquid crystal alignment film can be obtained.

In addition, in addition to the above-obtained substrate (first substrate), a transverse electric field drive type liquid crystal display element can be obtained by preparing a second substrate. In addition to using a substrate without a conductive film for driving in a transverse electric field instead of a substrate with a conductive film for driving in a transverse electric field, the second substrate is obtained by using the above steps [I] to [III] (because the substrate without a transverse electric field The substrate of the conductive film for driving, so in this case, there are cases referred to as steps [I']～[III'] for convenience) so as to obtain the second substrate with the liquid crystal alignment film endowed with alignment control ability.

The manufacturing method of the transverse electric field drive type liquid crystal display element has the following steps: [IV] arrange the above-mentioned obtained first and second substrates oppositely through the liquid crystal and in a manner that the liquid crystal alignment films of the first and second substrates are opposite to each other. 2. Substrate, so as to obtain the step of liquid crystal display element. Accordingly, a horizontal electric field drive type liquid crystal display element can be obtained.

Hereinafter, each step of [I] to [III] and [IV] included in the production method of the present invention will be described. ＜Step [I]＞ In step [I], a polymer composition containing a photosensitive main chain polymer and an organic solvent is coated on a substrate having a conductive film for driving in a transverse electric field, and then dried to form a coating film.

＜Substrate＞ The substrate is not particularly limited, but if the manufactured liquid crystal display device is a transmissive type, it is preferable to use a substrate with high transparency. In this case, it is not particularly limited, and a glass substrate, or a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like can be used. In addition, in consideration of application to reflective liquid crystal display elements, opaque substrates such as silicon wafers can be used.

<Conductive film for transverse electric field drive> The substrate has a conductive film for transverse electric field driving. As the conductive film, when the liquid crystal display device is a transmissive type, ITO (Indium Tin Oxide: Indium Tin Oxide), IZO (Indium Zinc Oxide: Indium Zinc Oxide), etc. can be mentioned, but not limited thereto. . Moreover, in the case of a reflection type liquid crystal display element, although the material etc. which reflect light, such as aluminum, are mentioned as a conductive film, it is not limited to these. As a method of forming a conductive film on a substrate, conventionally known methods can be used.

The method of applying the above-mentioned polymer composition to the substrate having the conductive film for driving in a transverse electric field is not particularly limited. The coating method is industrially generally performed by screen printing, offset printing, flexographic printing, inkjet method, or the like. As another coating method, there exist a dip method, a roll coater method, a slot coater method, a spin coater method (spin coater method), a spray method, etc., and these can be used according to the objective.

After coating the polymer composition on the substrate with the conductive film for transverse electric field driving, it can be heated at 30 to 150°C, preferably by means of heating such as a heating plate, a thermal cycle oven, or an IR (infrared) oven. A coating film is obtained by evaporating the solvent at 70 to 110°C. If the drying temperature is too low, the drying of the solvent tends to become insufficient, and if the heating temperature is too high, thermal imidization will proceed, and as a result, the photodecomposition reaction will proceed excessively due to polarized light exposure , in this case, it will become difficult to re-align in a certain direction by self-organization, so the alignment stability will be damaged. Therefore, the drying temperature at this time is preferably a temperature at which thermal imidization of a specific polymer does not substantially proceed from the viewpoint of liquid crystal alignment stability. If the thickness of the coating film is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may be reduced, so it is preferably 5nm to 300nm. Preferably it is 10 nm to 150 nm. Furthermore, after the step [I], before the next step [II], a step of cooling the substrate on which the coating film is formed to room temperature may be provided.

＜Step [II]＞ In step [II], polarized ultraviolet rays are irradiated to the coating film obtained in step [I]. When irradiating polarized ultraviolet rays to the film surface of the coating film, the polarized ultraviolet rays are irradiated from a direction that is fixed with respect to the substrate through a polarizing plate. As the ultraviolet rays to be used, ultraviolet rays having a wavelength of 100 nm to 400 nm can be used. It is preferable to select the most appropriate wavelength through a filter or the like according to the type of coating film to be used. In addition, for example, ultraviolet light having a wavelength of 240 nm to 400 nm is selected and used so as to selectively induce a photodecomposition reaction. As ultraviolet rays, for example, light emitted from a high-pressure mercury lamp or a metal halide lamp can be used.

The irradiation amount of polarized ultraviolet rays depends on the coating film used. The amount of irradiation is preferably set within the range of 1% to 70% of the amount of polarized ultraviolet light that realizes the maximum value of ΔA (hereinafter also referred to as ΔAmax), and is preferably set within the range of 1% to 50%. ΔA is the difference between the ultraviolet absorbance in the direction parallel to the polarization direction of polarized ultraviolet rays and the ultraviolet absorbance in the direction perpendicular to the polarization direction in the coating film.

＜Step [III]＞ In step [III], the coating film irradiated with polarized ultraviolet rays in step [II] is heated. By heating, alignment control ability can be imparted to a coating film. For the heating system, heating means such as a hot plate, a heat circulation type oven, or an IR (infrared ray) type oven can be used. The heating temperature is determined in consideration of the temperature at which the coating film used can exhibit good liquid crystal alignment stability and electrical characteristics.

The heating temperature is preferably within the temperature range where the main chain type polymer exhibits good liquid crystal alignment stability. If the heating temperature is too low, the amplifying effect of thermal anisotropy or thermal imidization tends to become insufficient. Also, if the heating temperature is higher than the temperature range, it will be caused by polarized light exposure. The endowed anisotropy tends to disappear, so that reorientation in one direction by self-organization becomes difficult in this case.

The thickness of the coating film formed after heating is due to the same reasons as described in step [I], preferably 5 nm to 300 nm, and more preferably 50 nm to 150 nm.

By having the above-mentioned steps, in the manufacturing method of the present invention, it is possible to realize highly efficient introduction of anisotropy to the coating film. In addition, a substrate with a liquid crystal alignment film can be manufactured efficiently.

＜Step [IV]＞ [IV] The step is to interpose the liquid crystal and obtain the substrate (the first substrate) with the liquid crystal alignment film on the conductive film for driving in the transverse electric field obtained by [III], and adopt the same above-mentioned [I']～[III' ] The obtained substrate (second substrate) with a liquid crystal alignment film that does not have a conductive film is disposed oppositely in such a manner that the liquid crystal alignment films of both sides face each other, and a liquid crystal cell is fabricated by a known method to produce a horizontal substrate. Steps for electric field driven liquid crystal display element. Still, step [I']～[III'] is in step [I], except using the substrate that does not have this horizontal electric field driving with conductive film, replaces the substrate that has the conductive film with horizontal electric field driving, can be with step [I] to [III] were performed in the same manner. The difference between steps [I]～[III] and steps [I']～[III'] is only the presence or absence of the above-mentioned conductive film, so the description of steps [I']～[III'] is omitted.

If an example of the manufacture of a liquid crystal cell or a liquid crystal display element is given, the following method can be exemplified: prepare the above-mentioned first and second substrates, spread spacers on the liquid crystal alignment film of a substrate, and use the liquid crystal alignment film surface as The method of laminating another substrate on the inside, injecting liquid crystal under reduced pressure and sealing it, or the method of laminating and sealing the substrate after dropping liquid crystal on the surface of the liquid crystal alignment film of the spacer, etc. In this case, it is preferable to use a substrate having electrodes having a comb-like structure for driving in a transverse electric field as one of the substrates. At this time, the diameter of the spacer is preferably from 1 μm to 30 μm, and more preferably from 2 μm to 10 μm. The spacer determines the distance between a pair of substrates sandwiching the liquid crystal layer, that is, the thickness of the liquid crystal layer.

The method of manufacturing a substrate with a coating film of the present invention is to irradiate polarized ultraviolet rays after coating a polymer composition on a substrate to form a coating film. Next, by heating, high-efficiency introduction of anisotropy into the main chain type polymer film is realized, and a substrate with a liquid crystal alignment film having the ability to control the alignment of liquid crystals is manufactured. The coating film used in the present invention utilizes the principle of molecular reorientation induced by the self-organization of the photoreaction based on the main chain, thereby realizing the introduction of high-efficiency anisotropy into the coating film. In the production method of the present invention, if the main chain type polymer has a structure of a photodecomposable group as the photoreactive group, the main chain type polymer is used to form a coating film on the substrate, and then irradiated with polarized light Ultraviolet rays, followed by heating, are made into liquid crystal display elements.

Therefore, the coating film used in the method of the present invention is irradiated with polarized ultraviolet rays and heat treatment to the coating film in order, so that the anisotropy can be introduced efficiently and the liquid crystal alignment with excellent alignment control ability can be obtained. membrane.

In addition, the coating film used in the method of the present invention is optimized by optimizing the irradiation amount of polarized ultraviolet rays to the coating film and the heating temperature in the heat treatment. Accordingly, more efficient introduction of anisotropy to the coating film can be realized.

For the introduction of highly efficient anisotropy of the coating film used in the present invention, the optimal amount of irradiation of polarized ultraviolet light corresponds to the amount that causes the photosensitive group in the coating film to undergo a photodecomposition reaction. Optimum exposure to polarized ultraviolet rays. As a result of irradiating polarized ultraviolet rays to the coating film used in the present invention, if there are few photosensitive groups undergoing photodecomposition reaction, sufficient photoreaction amount cannot be obtained. In this case, sufficient self-organization will not proceed even with subsequent heating.

Therefore, for the coating film used in the present invention, the optimal amount for photodecomposing the photosensitive group by irradiation of polarized ultraviolet rays is 0.1 mol % to 90 mol of the polymer film. % is more preferable, and it is more preferable to set it as 0.1 mol% - 80 mol%. By setting the amount of photosensitive groups that undergo photoreaction within such a range, self-organization in the subsequent heat treatment can be efficiently performed, and efficient anisotropy in the film can be achieved. form.

The coating film used in the method of the present invention optimizes the amount of photodecomposition reaction of the photosensitive group in the main chain of the polymer film by optimizing the irradiation amount of polarized ultraviolet rays. In addition, it is combined with the subsequent heat treatment to achieve efficient introduction of anisotropy to the coating film used in the present invention. In this case, the amount of suitable polarized ultraviolet rays can be determined from the evaluation of the ultraviolet absorption of the coating film used in the present invention.

That is, for the coating film used in the present invention, ultraviolet absorption in a direction parallel to the polarization direction of polarized ultraviolet rays and ultraviolet absorption in a direction perpendicular to the polarization direction after irradiation with polarized ultraviolet rays were measured. Based on the measurement results of ultraviolet absorption, the difference between the ultraviolet absorbance parallel to the polarization direction of the polarized ultraviolet rays and the ultraviolet absorbance perpendicular to the polarization direction in the coating film, ie, ΔA, was evaluated. Also, the maximum value (ΔAmax) of ΔA that can be realized in the coating film used in the present invention and the irradiation amount of polarized ultraviolet rays that realize the maximum value were obtained. In the manufacturing method of the present invention, the optimal amount of polarized ultraviolet rays irradiated in the manufacture of the liquid crystal alignment film can be determined based on the amount of polarized ultraviolet rays that realizes the ΔAmax.

According to the above, in order to realize the introduction of high-efficiency anisotropy to the coating film in the production method of the present invention, the temperature range in which the main chain type polymer imparts liquid crystal alignment stability can be used as a reference to determine the suitable temperature range as described above. The heating temperature is suitable. Therefore, for example, the temperature range in which the main chain type polymer used in the present invention gives liquid crystal alignment stability can be determined after considering the temperature at which the coating film used can exhibit good liquid crystal alignment stability and electrical properties. It is set according to the temperature range of the liquid crystal alignment film made of conventional polyimide or the like. That is, the temperature of the heating after polarized ultraviolet ray irradiation is preferably 150°C to 300°C, more preferably 180°C to 250°C. By setting in this way, larger anisotropy can be imparted to the coating film used in this invention.

Thereby, the liquid crystal display element provided by the present invention becomes to exhibit high reliability against external stress such as light or heat.

As described above, the substrate for a transverse electric field drive type liquid crystal display element manufactured using the polymer of the present invention or a transverse electric field drive type liquid crystal display element having the substrate can be suitably used for a large screen due to its excellent reliability. High-definition LCD TV, etc. Moreover, the liquid crystal alignment film manufactured by the method of the present invention has excellent liquid crystal alignment stability and reliability, so it can also be used in a variable phase shifter (variable phase shifter) using liquid crystals. The system can be suitably utilized for, for example, an antenna that can change the resonant frequency. [Example]

The abbreviated symbols used in the examples are as follows. NMP: N-methyl-2-pyrrolidone BCS: Ding Kelusu DA-1: The following structural formula (DA-1) DA-2: The following structural formula (DA-2) DA-3: The following structural formula (DA-3) DA-4: The following structural formula (DA-4) DA-5: The following structural formula (DA-5) DA-6: The following structural formula (DA-6) DA-7: The following structural formula (DA-7) DA-8: The following structural formula (DA-8) DA-9: The following structural formula (DA-9) DA-10: The following structural formula (DA-10) CA-1: The following structural formula (CA-1) CA-2: The following structural formula (CA-2) DE-1: The following construction formula (DE-1) DBOP: Diphenyl(2,3-dihydro-2-thio-3-benzoxazolyl)phosphonate

(However, Boc is a group represented by the following formula)

＜Measurement of Viscosity＞ In the synthesis example, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL, a conical rotor TE-1 (1°34', R24), and a temperature of 25°C. Come down to measure.

(Synthesis Example 1) In a 50mL four-neck flask with a stirring device and a nitrogen introduction tube, measure 0.485g of DA-1 (1.20mmol), 0.763g of DA-2 (2.80mmol), add 11.6g of NMP, and feed Nitrogen was stirred to disperse it. While stirring the diamine suspension under water cooling, 0.721 g of CA-1 (3.68 mmol) and 2.9 g of NMP were added, and stirred at 23° C. for 5 hours under a nitrogen atmosphere to obtain a polyamic acid-poly A solution of imide copolymer. The viscosity of the polyamic acid-polyimide copolymer solution at a temperature of 25°C is 268mPa. s. Separate 7.8 g of this polyamic acid-polyimide copolymer solution into a 100 mL Erlenmeyer flask with a stirring bar, add 6.8 g of NMP and 6.2 g of BCS, and stir at room temperature for 2 hours Thus, a liquid crystal alignment agent (A-1) was obtained.

(Synthesis Example 2) 1.89 g of DE-1 (7.25 mmol) was weighed in a 100 mL four-necked flask with a stirring bar, 41.1 g of NMP was added, and stirred to dissolve. Next, 2.37 g of triethylamine (23.4 mmol), 0.946 g of DA-1 (2.34 mmol), and 1.49 g of DA-2 (5.46 mmol) were added, stirred and dispersed. While stirring this suspension, 5.71 g of DBOP (14.9 mmol) was added, and 5.6 g of NMP was added, and it stirred under water cooling for 13 hours, and obtained the solution of the polyamide ester-polyimide copolymer. The viscosity of the polyamide ester-polyimide copolymer solution at a temperature of 25°C is 24.7mPa. s. The obtained polyamic acid ester solution-polyimide copolymer was poured into 354 g of methanol, stirring, and the precipitated deposit was collected by filtration. The precipitate was washed three times with methanol, and then dried under reduced pressure at a temperature of 100° C. to obtain a polyamide ester-polyimide copolymer powder. The powder 2.11g of the obtained polyamic acid ester-polyimide copolymer is weighed into the 100mL Erlenmeyer flask that puts into stirring bar, adds the NMP of 15.5g, and stirs at room temperature for 20 hours to make It dissolves. Next, NMP 15.2g and BCS 14.1g were added, and it stirred at room temperature for 2 hours, and obtained the liquid crystal aligning agent (A-2).

(Synthesis Example 3) In a 100mL four-neck flask with a stirring device and a nitrogen introduction tube, measure 1.94g of DA-1 (4.80mmol), 0.436g of DA-2 (1.60mmol), 0.477g of DA-3 (1.60mmol ), and 22.1 g of NMP was added, stirred and dispersed while feeding nitrogen. While stirring the diamine suspension under water cooling, 1.44 g of CA-1 (7.36 mmol) was added, and 9.5 g of NMP was added, and stirred at 23° C. for 5 hours under a nitrogen atmosphere to obtain a polyamic acid-poly A solution of imide copolymer. The viscosity of the polyamic acid-polyimide copolymer solution at a temperature of 25°C is 347mPa. s. Separate 14.5 g of this polyamic acid-polyimide copolymer solution into a 100 mL Erlenmeyer flask with a stirring bar, add 12.6 g of NMP and 11.6 g of BCS, and stir at room temperature for 2 hours Thus, a liquid crystal alignment agent (A-3) was obtained.

(Synthesis Example 4) In a 50mL four-neck flask with a stirring device and a nitrogen introduction tube, measure 1.62g of DA-1 (4.00mmol), 1.38g of DA-4 (6.00mmol), and add 30.0g of NMP, while sending Nitrogen was added while stirring to disperse. While stirring the diamine suspension under water cooling, 1.76 g of CA-1 (9.00 mmol) was added, and 12.9 g of NMP was added, and stirred at 40° C. for 16 hours under a nitrogen atmosphere to obtain a polyamic acid-poly A solution of imide copolymer. The viscosity of the polyamic acid-polyimide copolymer solution at a temperature of 25°C is 104mPa. s. Separate 15.3 g of the solution of this polyamic acid-polyimide copolymer into a 100 mL Erlenmeyer flask with a stirrer, add 6.1 g of NMP and 9.2 g of BCS, and stir at room temperature for 2 hours, Thus, a liquid crystal alignment agent (A-4) was obtained.

(Synthesis Example 5) In a 50mL four-neck flask with a stirring device and a nitrogen introduction tube, measure 1.21g of DA-1 (3.00mmol), 1.71g of DA-5 (7.00mmol), and add 29.5g of NMP, while sending Nitrogen was added while stirring to disperse. While stirring the diamine suspension under water cooling, 1.76 g of CA-1 (9.00 mmol) was added, and 12.7 g of NMP was added, and stirred at 40° C. for 16 hours under a nitrogen atmosphere to obtain polyamic acid- Solutions of polyimide copolymers. The viscosity of the polyamic acid-polyimide copolymer solution at a temperature of 25°C is 142mPa. s. Separate 15.6 g of this polyamic acid-polyimide copolymer solution into a 100 mL Erlenmeyer flask with a stirring bar, add 6.2 g of NMP, and 9.4 g of BCS, and stir at room temperature for 2 hours Thus, a liquid crystal alignment agent (A-5) was obtained.

(Synthesis Example 6) In a 50mL four-neck flask with a stirring device and a nitrogen introduction tube, measure 1.61g of DA-1 (4.00mmol), 1.55g of DA-6 (6.00mmol), and add 31.1g of NMP, while sending Nitrogen was added while stirring to disperse. While stirring the diamine suspension under water cooling, 1.76 g of CA-1 (9.00 mmol) was added, and 13.3 g of NMP was added, and stirred at 40° C. for 16 hours under a nitrogen atmosphere to obtain polyamic acid- Solutions of polyimide copolymers. The viscosity of the polyamic acid-polyimide copolymer solution at a temperature of 25°C is 117mPa. s. Separate 15.2 g of this polyamic acid-polyimide copolymer solution into a 100 mL Erlenmeyer flask with a stirring bar, add 6.1 g of NMP and 9.1 g of BCS, and stir at room temperature for 2 hours Thus, a liquid crystal alignment agent (A-6) was obtained.

(Synthesis Example 7) In a 50mL four-neck flask with a stirring device and a nitrogen introduction tube, measure 1.46g of DA-1 (3.60mmol), 1.62g of DA-7 (5.40mmol), and add 29.4g of NMP, while sending Nitrogen was added while stirring to disperse. While stirring the diamine suspension under water cooling, 1.59 g of CA-1 (8.10 mmol) was added, and 12.6 g of NMP was added, and stirred at 40° C. for 16 hours under a nitrogen atmosphere to obtain a polyamic acid-poly A solution of imide copolymer. The viscosity of the polyamic acid-polyimide copolymer solution at a temperature of 25°C is 139mPa. s. Separate 15.6 g of this polyamic acid-polyimide copolymer solution into a 100 mL Erlenmeyer flask with a stirring bar, add 6.2 g of NMP, and 9.4 g of BCS, and stir at room temperature for 2 hours Thus, a liquid crystal alignment agent (A-7) was obtained.

(Synthesis Example 8) In a 50mL four-neck flask with a stirring device and a nitrogen introduction tube, measure 2.59g of DA-1 (6.40mmol), 0.638g of DA-8 (1.60mmol), and add 29.2g of NMP, while sending Nitrogen was added while stirring to disperse. While stirring the diamine suspension under water cooling, 1.41 g of CA-1 (7.20 mmol) was added, and 12.5 g of NMP was added, and stirred at 40° C. for 16 hours under a nitrogen atmosphere to obtain a polyamic acid-poly A solution of imide copolymer. The viscosity of the polyamic acid-polyimide copolymer solution at a temperature of 25°C is 191mPa. s. Separate 14.7 g of this polyamic acid-polyimide copolymer solution into a 100 mL Erlenmeyer flask with a stirring bar, add 5.9 g of NMP and 8.8 g of BCS, and stir at room temperature for 2 hours Thus, a liquid crystal alignment agent (A-8) was obtained.

(Synthesis Example 9) In a 50mL four-neck flask with a stirring device and a nitrogen introduction tube, measure 1.46g of DA-1 (3.60mmol), 1.08g of DA-7 (3.60mmol), 0.615g of DA-9 (1.80mmol ), and 29.9 g of NMP was added, and stirred while feeding nitrogen to disperse it. While stirring the diamine suspension under water cooling, 1.59 g of CA-1 (8.10 mmol) was added, and 12.8 g of NMP was added, and stirred at 40° C. for 16 hours under a nitrogen atmosphere to obtain polyamic acid-polyamide Solutions of imine copolymers. The viscosity of the polyamic acid-polyimide copolymer solution at a temperature of 25°C is 108mPa. s. Separate 15.1 g of the polyamic acid-polyimide copolymer solution into a 100 mL Erlenmeyer flask with a stirring bar, add 6.0 g of NMP and 9.1 g of BCS, and stir at room temperature for 2 hours Thus, a liquid crystal alignment agent (A-9) was obtained.

(Synthesis Example 10) In a 50mL four-neck flask with a stirring device and a nitrogen introduction tube, measure 1.29g of DA-1 (3.20mmol), 0.961g of DA-7 (3.20mmol), 0.891g of DA-10 (1.60mmol ), and 28.7 g of NMP was added, and stirred while feeding nitrogen to disperse it. While stirring the diamine suspension under water cooling, 1.41 g of CA-1 (7.20 mmol) was added, and 12.3 g of NMP was added, and stirred at 40° C. for 16 hours under a nitrogen atmosphere to obtain a polyamic acid-poly A solution of imide copolymer. The viscosity of the polyamic acid-polyimide copolymer solution at a temperature of 25°C is 116mPa. s. Separate 15.0 g of this polyamic acid-polyimide copolymer solution into a 100 mL Erlenmeyer flask with a stirring bar, add 6.0 g of NMP, and 9.0 g of BCS, and stir at room temperature for 2 hours Thus, a liquid crystal alignment agent (A-10) was obtained.

(comparative synthesis example 1) In a 50mL four-neck flask with a stirring device and a nitrogen introduction tube, measure 0.364g of DA-1 (0.90mmol), 0.572g of DA-2 (2.10mmol), and add 9.2g of NMP, while sending Nitrogen was added while stirring to disperse. While stirring the diamine suspension under water cooling, 0.632 g of CA-2 (2.82 mmol) was added, and 2.3 g of NMP was added, and stirred at 40° C. for 15 hours under a nitrogen atmosphere to obtain polyamic acid- Solutions of polyimide copolymers. The viscosity of the polyamic acid-polyimide copolymer solution at a temperature of 25°C is 326mPa. s. Separate 7.5 g of this polyamic acid-polyimide copolymer solution into a 100 mL Erlenmeyer flask with a stirring bar, add 6.5 g of NMP, and 6.0 g of BCS, and stir at room temperature for 2 hours Thus, a liquid crystal alignment agent (B-1) was obtained.

＜Production of liquid crystal cell for evaluation of liquid crystal alignment＞ The following is a method of fabricating a liquid crystal cell for evaluating liquid crystal alignment. A liquid crystal cell having a configuration of an FFS system liquid crystal display element was produced. First prepare the substrate with the electrodes attached. The substrate is a glass substrate having a size of 30 mm×35 mm and a thickness of 0.7 mm. The IZO electrode constituting the counter electrode is formed on the entire surface of the substrate as the first layer. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by CVD is formed as the second layer. The SiN film of the second layer has a film thickness of 500 nm and functions as an interlayer insulating film. On the SiN film of the second layer, comb-shaped pixel electrodes formed by patterning the IZO film are arranged as the third layer to form two types of pixels, the first pixel and the second pixel. The size of each pixel is about 10 mm in length and about 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer is the same as the figure described in Japanese Patent Laid-Open No. 2014-77845 (Japanese Laid-Open Patent Publication), and has a comb-tooth shape formed by arranging a large number of electrode elements in the shape of "く" with a curved central part. shape. The width in the short-side direction of each electrode element was 3 μm, and the interval between electrode elements was 6 μm. The pixel electrode forming each pixel is composed of many arrays of electrode elements in the shape of a "く" shape with a curved central part. Therefore, the shape of each pixel is not a rectangular shape, but has the same shape as the electrode elements that are curved at the central part. The shape of a bold "く" character. In addition, each pixel is divided up and down with a curved portion in the center as a boundary, and has a first region above the curved portion and a second region below the curved portion.

When comparing the first region and the second region of each pixel, the formation directions of the electrode elements constituting these pixel electrodes are different. That is, when the polarizing plane of polarized ultraviolet rays described later is projected onto the line segment direction of the substrate as a reference, in the first region of the pixel, the electrode element of the pixel electrode is formed at an angle (clockwise) of +10°. In the second region of the pixel, the electrode element of the pixel electrode is formed at an angle (clockwise) of -10°. That is, the first region and the second region of each pixel are configured as follows: In-plane switching of the liquid crystal substrate induced by applying a voltage between the pixel electrode and the counter electrode (in-plane switching) The directions will be opposite to each other.

Next, the liquid crystal alignment agents obtained in the synthesis examples and comparative synthesis examples were filtered through a 1.0 μm filter, and then coated onto the prepared substrate with the above-mentioned electrodes by spin coating. Next, it was dried for 90 seconds on a hot plate set at 70°C. Next, using an exposure apparatus made by Ushio Electric Co., Ltd.: APL-L050121S1S-APW01, the substrate was irradiated with linearly polarized light of ultraviolet rays in the vertical direction through a wavelength selection filter and a polarizing plate. At this time, the direction of the line segment projecting the polarization plane of the polarized ultraviolet rays onto the substrate was set so that the direction of the polarization plane was inclined by 10° with respect to the IZO comb electrode of the third layer. Next, firing was performed for 30 minutes in an IR (infrared ray) oven set at 230° C. to obtain a substrate with a 100-nm-thick polyimide liquid crystal alignment film subjected to alignment treatment. Also, as the opposite substrate, a glass substrate with a columnar spacer with a height of 4 μm formed on the inside of the ITO electrode is also carried out in the same manner as above, and a polyimide liquid crystal alignment film with an alignment treatment is obtained. the substrate. These 2 substrates with liquid crystal alignment film are used as a group, and the sealant is printed in the form of leaving a liquid crystal injection port on one substrate, and the other substrate is facing each other with the liquid crystal alignment film surface Laminate and press in such a way that the direction of the line segment projecting the polarization plane of the polarized ultraviolet light onto the substrate is parallel. After that, the encapsulant was hardened and empty cells were produced with a cell gap of 4 μm. Liquid crystal MLC-7026-100 (Merck negative liquid crystal) was injected into this empty cell by the depressurization injection method, and the injection port was sealed, and the liquid crystal cell of the FFS system was obtained. Afterwards, the obtained liquid crystal unit cell was heated at 120° C. for 30 minutes, and left overnight at 23° C. for evaluation of liquid crystal alignment.

＜Evaluation of liquid crystal alignment＞ Using the liquid crystal unit cell, in a constant temperature environment of 70° C., an AC voltage of 16 VPP was applied at a frequency of 30 Hz for 96 hours. After that, between the pixel electrode and the counter electrode of the liquid crystal cell was short-circuited, and left overnight at 23° C. as it is.

After being placed, the liquid crystal cell is placed between two polarizers arranged so that the polarization axes are perpendicular to each other, and the backlight is turned on in advance without an applied voltage, and the arrangement angle of the liquid crystal cell is adjusted so that the transmission The brightness of the light becomes the minimum. Moreover, the rotation angle at the time of rotating a liquid crystal cell from the angle at which the 2nd area|region of a 1st pixel becomes the darkest to the angle at which the 1st area becomes the darkest was calculated as angle Δ. Also in the second pixel, the same angle Δ is calculated by comparing the second area with the first area. Moreover, the average value of the angle Δ value of the 1st pixel and the 2nd pixel was calculated as the angle Δ of the liquid crystal cell. When the value of the angle Δ of the liquid crystal cell is less than 0.2°, it is defined and evaluated as "good", and when the value of the angle Δ is more than 0.2°, it is defined and evaluated as "poor".

＜Evaluation of Membrane Strength＞ The liquid crystal alignment agents obtained in the synthesis examples and comparative synthesis examples were filtered through a 1.0 μm filter, and then coated onto the prepared substrate with the above-mentioned electrodes by spin coating. Next, it was dried for 90 seconds on a hot plate set at 70°C. Next, firing was performed for 30 minutes in an IR (infrared ray) oven set at 230° C. to obtain a substrate with a 100-nm-thick polyimide liquid crystal alignment film subjected to alignment treatment. This polyimide film was rubbed with rayon cloth: YA-20-R manufactured by Yoshikawa Chemical Industry (roller diameter: 120 mm, roll rotation speed: 1000 rpm, moving speed: 20 mm/sec, press length: 0.3 mm). The presence or absence of scratches or grinding debris on the surface of the polyimide film was observed using a confocal laser microscope. Those without scratches or grinding debris were set as "good", and those with scratches or grinding debris were set as "defective".

(Example 1) Using the liquid crystal alignment agent (A-1) obtained in the synthesis example 1, the liquid crystal cell as described above was produced. Irradiation of polarized ultraviolet rays was performed using a high-pressure mercury lamp with a wavelength selection filter: 240LCF, and a 254nm type polarizing plate. The irradiation amount of polarized ultraviolet rays was measured using an illuminance meter UVD-S254SB manufactured by Ushio Electric Co., Ltd., and ^three types of liquid crystal cells were produced with polarized ultraviolet irradiation amounts of 200, 300, and 400 mJ/cm2 at a wavelength of 254 nm.

As a result of evaluating the liquid crystal alignment of these liquid crystal cells, the optimum polarized ultraviolet irradiation dose for the angle Δ is 300 mJ/cm ² , and the angle Δ is 0.05°, which is good. Moreover, the result of evaluating film strength as described above using the liquid crystal alignment agent (A-1) obtained in the synthesis example 1 was favorable.

(Embodiments 2-10) Except having used the liquid crystal alignment agent obtained in synthesis examples 2-10, it evaluated the liquid crystal alignment property and film strength by the same method as Example 1.

(comparative example 1) Except for using the liquid crystal alignment agent obtained in Comparative Synthesis Example 1, the liquid crystal alignment and film strength were evaluated in the same manner as in Example 1.

Table 1 shows the optimal polarized ultraviolet irradiation amount, the evaluation results of liquid crystal alignment, and the evaluation results of film strength at angle Δ when using the liquid crystal alignment agents obtained in the synthesis examples and comparative synthesis examples.

As shown in Table 1, in Examples 1 to 10, the difference in alignment azimuth angle (that is, the angle Δ) before and after AC driving is less than 0.2°, which is good, so the improvement of the display quality of the liquid crystal display element is excellent. In addition, since the film strength is also good, it is difficult to cause grinding or peeling of the liquid crystal alignment film even if it is subjected to thinning processing by thinning (chemical polishing) when producing a liquid crystal display element. On the other hand, in Comparative Example 1, the angle Δ was 0.2° or more, which was unfavorable, and the film strength was also unfavorable.

It was confirmed that the liquid crystal display element manufactured by the method of the present invention showed very excellent afterimage characteristics and film strength. [Industrial Utilization]

The substrate for a transverse electric field drive type liquid crystal display element manufactured using the composition of the present invention or the transverse electric field drive type liquid crystal display element having the substrate is excellent in long-term stability of liquid crystal alignment, so it can be suitably used for large screens and High-definition LCD TV, etc. Also, since the substrate for a transverse electric field driven liquid crystal display element manufactured using the composition of the present invention or a transverse electric field driven liquid crystal display element having the substrate has excellent film strength, it can also be suitably used for thinning. Small mobile phones or smart phones, etc. Furthermore, the liquid crystal alignment film manufactured by the method of the present invention can also be used in a variable phase shifter using liquid crystals, and the variable phase shifter can be suitably used in, for example, antennas that can change the resonant frequency.

Claims (8)

A liquid crystal alignment agent, which contains: (A) a diamine component comprising a diamine represented by the following formula (1), and cyclobutane tetracarboxylic acid diamine represented by the following formula (2-1) The polymer obtained by the acid component of an anhydride, and (B) organic solvent,

. The liquid crystal alignment agent according to claim 1, wherein the above-mentioned polymer is at least one selected from the group consisting of polyimide precursors and polyimides thereof. The liquid crystal alignment agent according to claim 1 or 2, wherein R in the above formula (2-2) are all methyl groups. The liquid crystal alignment agent according to claim 1 or 2, wherein the aforementioned polymer is represented by the following formula (3),

(In formula (3), X ₁ is a tetravalent organic group derived from tetracarboxylic acid derivatives and said tetracarboxylic acid derivatives comprise the structure of the above formula (2-1), Y ₁ is derived from diamines A divalent organic group and the diamine contains the structure of formula (1), R ₁₁ is a hydrogen atom or an alkyl group with 1 to 5 carbons). The liquid crystal alignment agent according to claim 4, wherein, relative to the total polymer contained in the liquid crystal alignment agent, more than 10 mol% of the polymer having the structural unit represented by the aforementioned formula (3) is contained. A liquid crystal alignment film for a transverse electric field driven liquid crystal display element, which is obtained by using the liquid crystal alignment agent according to any one of Claims 1-5. A substrate having a liquid crystal alignment film for a transverse electric field driven liquid crystal display element according to Claim 6. A horizontal electric field driven liquid crystal display element, which has the substrate as claimed in claim 7.