TW201514219A - Method for producing liquid crystal aligning film, photo aligning agent and liquid crystal display element - Google Patents

Abstract

A method for producing a liquid crystal aligning film is provided, which obtains a liquid crystal display element that an accumulation amount of a residual electric charge is less and a high voltage retention rate is rendered. The liquid crystal aligning film is produced by a method including steps below: a step for coating a liquid crystal aligning agent on a substrate to form a coating film, wherein the liquid crystal aligning agent includes a (A) polymer and a (B) polymer as at least one polymer constituent selected from a group consisting of a polyamic acid, a polyamic acid ester and a polyimide, and the (A) polymer is a polymer having a structure (Y) represented by Formula (1) below in a main chain (wherein, in a situation that X1 is -NH-, an amide bonding formed by a polymerization reaction is excluded); a step for producing the liquid crystal aligning film by irradiating light to the coating film.

Description

Method for producing liquid crystal alignment film, photoalignment agent and liquid crystal display element

The present invention relates to a method for producing a liquid crystal alignment film, a photo-aligning agent, and a liquid crystal display device, and more particularly to a technique for imparting liquid crystal alignment to a film by a photo-alignment technique.

At present, as the liquid crystal display element, various driving methods such as an electrode structure or physical properties of liquid crystal molecules to be used have been developed. For example, a twisted nematic (TN) type or a super twisted nematic (Super Twisted Nematic) has been known. Vertical liquid electric field methods such as STN), Vertical Alignment (VA), and various liquid crystal displays such as In-Plane Switching (IPS) type and Fringe Field Switching (FFS) type element. In the liquid crystal display device of the vertical electric field type, an electrode is formed on each of a pair of substrates arranged in the opposite direction, and an electric field is generated in a direction perpendicular to the substrate. In contrast, in the transverse electric field mode In the liquid crystal display device, an electrode is formed on one of a pair of substrates, and an electric field is generated in a direction parallel to the substrate. Therefore, it is known that the liquid crystal display element of the transverse electric field type has been conventionally Compared to the longitudinal electric field method, contrast or viewing angle characteristics can be improved.

The liquid crystal display element controls the alignment state of the liquid crystal molecules by using the liquid crystal alignment film formed on the substrate. As a material of the liquid crystal alignment film, polylysine or polyimide is generally used from the viewpoints of various properties such as heat resistance, mechanical strength, and affinity with liquid crystal. In addition, as a method of imparting a liquid crystal alignment ability to a polymer film formed of a liquid crystal alignment agent, a photo-alignment method using photo-isomerization, photodimerization, photodegradation, or the like has been proposed as a technique in place of the rubbing method. This photo-alignment method is a method of controlling the alignment of liquid crystal molecules by imparting anisotropy to the film by irradiating the radiation-sensitive organic thin film formed on the substrate with polarized or non-polarized radiation. Compared with the conventional rubbing method, the generation of dust or static electricity in the step can be suppressed by this method, so that occurrence of display failure or deterioration in yield due to dust or the like can be suppressed. Further, it has an advantage that the organic film formed on the substrate can be uniformly imparted with the liquid crystal alignment ability.

Various liquid crystal alignment agents have been proposed as liquid crystal alignment agents to be used in the photo-alignment method (see, for example, Patent Document 1 to Patent Document 4). Patent Document 1 discloses a liquid crystal alignment agent containing a polymer having a group containing a chalcone structure in a side chain, and Patent Document 2 discloses a liquid crystal alignment agent containing a polymer having a flavonoid structure. Further, Patent Document 3 discloses a liquid crystal alignment agent containing a polymer having an azobenzene structure or a fluorene structure, and Patent Document 4 discloses a liquid crystal alignment agent containing a low molecular weight azo compound.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-307736

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-163646

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2002-250924

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2004-83810

In the liquid crystal display device of the transverse electric field type, it has a wide viewing angle characteristic or a good contrast characteristic, and on the other hand, an afterimage (an image retention mark) due to residual charge accumulation becomes a problem.

Further, by applying the liquid crystal alignment film obtained by the photo-alignment method to a liquid crystal display device of a transverse electric field type, it is expected that the above-described characteristics of the photo-alignment method can be obtained. However, in the case of a photo-alignment method in which a chemical change occurs by irradiation of ultraviolet rays or the like, there is a general tendency that electrical characteristics are inferior to those of a conventional liquid crystal alignment film by rubbing treatment. In particular, in the case of photodecomposition accompanying a polymer, there is a problem in that impurity ions are increased in the liquid crystal cell, and the voltage holding ratio is liable to lower. In addition, it is estimated that the alignment control force of the liquid crystal of the liquid crystal alignment film obtained by the photo-alignment method is not sufficient, and it is one cause of the retention in the liquid crystal display device of the transverse electric field type. On the other hand, as the liquid crystal panel has been improved in quality in recent years, a liquid crystal display element which is excellent in electrical characteristics or low afterimage characteristics of a liquid crystal display element is required as a liquid crystal display element.

The present invention has been made in view of the above problems, and a main object thereof is to provide a liquid crystal display element which is capable of obtaining a small amount of residual charge and exhibiting a high voltage holding ratio. A method of manufacturing a liquid crystal alignment film.

The present inventors have actively studied in order to achieve the above-described problems of the prior art, and have focused on a photo-Fries rearrangement reaction as a mechanism for generating anisotropy on a film by light irradiation. The light Fres rearrangement reaction is a change in the skeleton of the molecular structure by rearranging the phenyl ester into an aromatic hydroxy ketone. Further, the inventors of the present invention have used a polyglycolic acid, a polyamidite having a specific structure (a structure in which an ester group or a thioester group is bonded to an aromatic ring) in the main chain, based on the point of interest. At least one polymer of the polyimine is used as a part of the polymer component of the liquid crystal alignment agent to form a liquid crystal alignment film by a photo-alignment method. As a result, it has been found that the above problems can be solved, and the present invention has been completed. Specifically, the present invention provides the following method for producing a liquid crystal alignment film, a photo alignment agent, and a liquid crystal display device.

The present invention provides, in one embodiment, a method for producing a liquid crystal alignment film, comprising the steps of: applying a liquid crystal alignment agent onto a substrate to form a coating film, wherein the liquid crystal alignment agent comprises (A) a polymer and ( B) a polymer as at least one polymer component selected from the group consisting of polylysine, polyphthalate, and polyimine, and (A) the polymer has the following formula in the main chain ( 1) a polymer represented by the structure (Y) (wherein, in the case where X ¹ is -NH-, except for a guanamine bond formed by a polymerization reaction); the coating film is irradiated with light to form a liquid crystal Step of aligning the film; [Chemical 1]

(In the formula (1), X ¹ is a sulfur atom, an oxygen atom or -NH-; "*" represents a bond, respectively; wherein at least one of the two "*"s is bonded to the aromatic ring).

In another aspect, the present invention provides a photo-aligning agent comprising the (A) polymer and (B) a polymer. Further, in another aspect, there is provided a liquid crystal display element comprising a liquid crystal alignment film formed using the above-described production method.

In a liquid crystal display device of a transverse electric field type, by using a liquid crystal alignment agent in which a polymer having a structure represented by the formula (1) in a main chain and a polymer different therefrom are used, When a liquid crystal alignment film is produced, a liquid crystal display element having a high voltage holding ratio and a small amount of residual charge accumulation can be obtained.

Hereinafter, a method for producing a liquid crystal alignment agent for photoalignment (hereinafter also referred to as "photoalignment agent") and a method for producing a liquid crystal alignment film using the photoalignment agent will be described. First, each component of the photo-aligning agent and other components arbitrarily formulated as needed will be described.

<polymer composition>

The photo-aligning agent of the present invention contains at least one polymer selected from the group consisting of polyglycolic acid, polyphthalate, and polyimine as a polymer component. Further, the polymer contains at least two polymers of (A) a polymer and (B) a polymer. Hereinafter, the (A) polymer and the (B) polymer will be described in order.

[(A) polymer]

The (A) polymer is at least one selected from the group consisting of polylysine, polyphthalate, and polyimine, and has a structure represented by the following formula (1) in the main chain (Y) (In the case where X ¹ is -NH-, except for the indole bond formed by the polymerization reaction).

(In the formula (1), X ¹ is a sulfur atom, an oxygen atom or -NH-. "*" represents a bond, wherein at least one of the two "*" is bonded to the aromatic ring)

Examples of the aromatic ring bonded to "*" in the formula (1) include a benzene ring, a naphthalene ring, an anthracene ring and the like. From the viewpoint of liquid crystal alignment and transparency, a benzene ring is preferred among these. Among the two "*"s in the formula (1), the structure in which the other "*" is bonded is not particularly limited, and examples thereof include a chain hydrocarbon structure, an aliphatic ring, an aromatic ring, and a hetero ring. In terms of high sensitivity to light, one of the two "*"s is preferably bonded to the aromatic ring, and the other is bonded to a group selected from the group consisting of an aromatic ring, an aliphatic ring and a heterocyclic ring. At least one of the groups, particularly preferably two "*" They are all bonded to the aromatic ring. Further, from the viewpoint of reducing the retention of the liquid crystal display element, it is preferred that one of the two "*"s is bonded to the aromatic ring and the other is bonded to the aliphatic ring, and more preferably the aliphatic ring is cyclohexane. ring.

In terms of sensitivity in terms of light, X ¹ preferably is a sulfur atom, obtained in terms of aspect and the aspect of easy selection of monomers which can be used widely, X ¹ is preferably an oxygen atom.

The (A) polymer in the invention may be a tetracarboxylic acid derivative and at least one selected from the group consisting of tetracarboxylic dianhydride, tetracarboxylic acid diester, and tetracarboxylic acid diester dihalide. Obtained by an amine reaction. Hereinafter, polyacrylic acid, polyphthalate, and polyimine as the (A) polymer will be described.

Further, the term "main chain" of the polymer in the present specification means the longest "dry" portion of the polymer including the atomic chain. Among them, the portion allowing the "dry" includes a ring structure. In this case, the atoms constituting the ring structure are respectively bonded to other atoms constituting the "dry" portion, and the entire ring structure is present in the main chain. Therefore, the phrase "having a structure (Y) in the main chain" means that the structure constitutes a part of the main chain. However, in the polymer (A), the portion (Y) in which the structure (Y) is not present in the main chain, for example, a side chain (a portion branched from the "dry" of the polymer) is not excluded.

<polylysine>

The polyamic acid (hereinafter also referred to as "(A) poly-proline)" as the (A) polymer in the present invention may, for example, be: [i] comprising a tetracarboxylic acid having the structure (Y) One or two or more kinds of tetracarboxylic acids of dianhydride (hereinafter also referred to as "specific tetracarboxylic dianhydride") a method of reacting a dianhydride with a diamine having no structure (Y); [ii] a tetracarboxylic dianhydride having no structure (Y) and a diamine having the structure (Y) (hereinafter also referred to as "specific diamine"), a method in which one or two or more kinds of diamines are reacted; [iii] one or two or more kinds of tetracarboxylic dianhydrides containing a specific tetracarboxylic dianhydride, and specific A method of reacting one or two or more kinds of diamines of a diamine.

[Specific tetracarboxylic dianhydride]

The specific tetracarboxylic dianhydride is a compound having a group represented by the above formula (1) and two acid anhydride groups (-CO-O-CO-), and specifically, for example, represented by the following formula (a).

(In the formula (a), X ¹ is a sulfur atom, an oxygen atom or -NH-. R ³ and R ⁴ each independently represent a monovalent organic group having one acid anhydride group, and at least one of R ³ and R ⁴ has a fragrance. Ring. At least one bond of "-CO-X ¹ -" is bonded to the aromatic ring)

The monovalent organic group of R ³ and R ⁴ in the above formula (a) is not particularly limited as long as it has an acid anhydride group. Examples of the structure of the moiety other than the acid anhydride group include a hydrocarbon group having 1 to 40 carbon atoms, a hydrogen atom of the hydrocarbon group substituted with a halogen atom or the like, or a carbon-carbon bond between the hydrocarbon groups. -O-", "-S-", "-CO-", "-CO-O-", "-CO-S-", "-SO ₂ -", "-N=N-", "- Bases such as NH-", "-CO-NH-", etc.

Here, the "hydrocarbon group" in the present specification may be a saturated hydrocarbon group or an unsaturated hydrocarbon group, and means a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. In addition, the "chain hydrocarbon group" means a linear hydrocarbon group and a branched hydrocarbon group which do not include a cyclic structure in the main chain and include only a chain structure. The "alicyclic hydrocarbon group" is a hydrocarbon group which has a structure including only an alicyclic hydrocarbon as a ring structure and does not contain an aromatic ring structure. Among them, it is not necessary to include only a structure of an alicyclic hydrocarbon, and a structure having a chain structure in a part thereof. The "aromatic hydrocarbon group" means a hydrocarbon group containing an aromatic ring structure as a ring structure. Among them, it is not necessary to include only the aromatic ring structure, and a structure of a chain structure or an alicyclic hydrocarbon may be contained in a part thereof.

The acid anhydride group of R ³ and R ⁴ is preferably bonded to an aromatic ring, and more preferably, the aromatic ring is a benzene ring or a naphthalene ring. Specifically, R ³ and R ^{4 are} preferably a group represented by the following formula (a1-1) to formula (a1-3), or a group having any of these groups.

(where "*" means the bond key on "-O-C(=O)-", "-S-C(=O)-" or "-NH-CO-")

From the viewpoint of improving the liquid crystal alignment property, R ³ and R ⁴ more preferably have a group represented by the above formula (a1-1) or formula (a1-3), and still more preferably have formula (a1-1). The base represented. Further, it is preferable that the bonding bond in each of the formulas (a1-1) to (a1-3) is bonded to "-OC(=O)-", "-SC(=O)-" or "-NH"-CO-" on the carbonyl group.

In the case where one of R ³ and R ⁴ is a group represented by any one of the formulae (a1-1) to (a1-3), the other group may be exemplified by the following formula (a2) The base of the representation.

(In the formula (a2), Ar ¹ is a benzene ring or a naphthalene ring, and X ² is -O-CO-* ³ , -S-CO-* ³ , -NH-CO-* ³ , -O-, -CO- O-* ³ , -CO-S-* ³ or -CO- (where "*3" represents a bond bonded to Ar ¹ ). R ⁵ and R ⁷ are each independently a cyclohexyl group and a phenyl group. Or a biphenyl group, which may have a substituent at the ring moiety. R ⁶ is a divalent chain hydrocarbon group having 1 to 20 carbon atoms and a carbon group at the chain hydrocarbon group in the case where n1 = n3 = 1. The position between the carbon bonds or adjacent to the carbon atom includes a divalent group of "-O-", -O-, -S-, -CO-, -CO-O-, -CO-S-, -SO2-, - N=N-, -NH- or -CO-NH-, in the case of n1=0 or n3=0, is a divalent chain hydrocarbon group having 1 to 20 carbon atoms or a carbon-carbon bond at the chain hydrocarbon group A divalent group containing "-O-". n1, n2, n3, and m1 are each independently 0 or 1. "*" indicates a binding bond)

Ar ^{1 of} the formula (a2) is preferably a benzene ring in terms of good liquid crystal alignment and transparency. In terms of good sensitivity to light, X ² is preferably -O-CO-* ³ , -S-CO-* ³ , -CO-O-* ³ or -CO-S-* ³ , more preferably -O-CO-* ³ or -S-CO-* ³ .

Examples of the divalent chain hydrocarbon group having 1 to 20 carbon atoms in R ⁶ include a methylene group, an ethyl group, a propylene group, a butyl group, a pentane group, a hexyl group, a heptane group, and a octyl group. The diyl group, the indenyl group, the indenyl group, the dodecanediyl group and the like are preferably linear. By setting R ⁶ to a structure having high flexibility, the heating realignment of the alignment film at the time of post-baking can be increased. The preferred structure of R ⁶ is, for example, a structure represented by the following formula (3).

(In equation (3), k and i are each independently 0 or 1, l is an integer from 2 to 9, and j is an integer from 1 to 4. "*" indicates a binding bond.)

In the formula (3), when j is 2 or more, l and i may be the same or different between the repeating units. When the n1 of the formula (a2) is 0, the group represented by the formula (3) is preferably bonded with an alkanediyl group with respect to X ² ; in the case of n3 = 0, preferably with respect to The -CO-X ¹ - in the formula (a) is bonded with an alkanediyl group.

R ⁵ and R ⁷ are preferably a phenylene group or a stretched phenyl group in terms of high reactivity with light, and are preferably a cyclohexylene group in terms of reducing the retention of the liquid crystal display element.

When the ring moiety of R ⁵ and R ⁷ has a substituent, the substituent includes, for example, a fluorine atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a carbon number of 1. ~3 fluoroalkyl and the like. As for the position of the substituent, R ⁵ may be any of an ortho, meta or para position with respect to X ² , and may be an ortho position relative to "-CO-X ¹ -" with respect to R ⁷ . Any one of the position and the position. In the case where "-CO-O-" or "-CO-S-" is bonded to the benzene ring, the substituent is preferably ortho to the viewpoint of improving the sensitivity to light.

Preferably, at least one of n1 and n3 is 1. From the viewpoint of improving the liquid crystal alignment property, n2 is preferably 1, and is preferably 0 from the viewpoint of improving photoreactivity. M1 is preferably 1 in terms of improving the performance of anisotropy by light irradiation.

Further, the reason why the coating film containing the (A) polymer exhibits liquid crystal alignment ability by light irradiation is not determined, mainly because the light Fres rearrangement reaction is due to photolysis of the base "-CO-X ¹ -" or Because the two are still not clear. Therefore, in the case where "-CO-O-", "-CO-S-" or "-CO-NH-" is bonded to the benzene ring, there is a substituent in the ortho position relative to the group. On the other hand, the reason why the sensitivity to light is increased is not clear. However, when photodecomposition is preferentially generated, it is difficult to carry out rearrangement by introducing a substituent into the benzene ring, and as a result, photodecomposition is promoted.

Preferable specific examples of the group represented by the formula (a2) include a group represented by each of the following formulas (a2-1) to (a2-46).

(where "*" indicates the bond with X ¹ )

Specific examples of the specific tetracarboxylic dianhydride include the following formula (a-1). a compound represented by each of the formula (a-37). As the specific tetracarboxylic dianhydride, one type of these may be used alone or two or more types may be used in combination.

[化12]

[Chemistry 13]

[化15]

Among the above compounds, those having a high sensitivity to light are preferably compounds represented by the above formulas (a-1) to (a-14), and more preferably the formula (a-1)~ A compound represented by each of the formula (a-11), the formula (a-13), and the formula (a-14). Further, in order to impart appropriate rigidity and flexibility to the polymer, the realignment property of the alignment film can be improved by heating during post-baking, and it is preferable that the formula (a-15) to the formula (a-15) A-24). Further, from the viewpoint of photoreactivity, a compound represented by each of the above formula (a-5) and formula (a-25) to formula (a-29) is preferred.

[Other tetracarboxylic dianhydride]

In the case of the methods of [i] and [iii], as the tetracarboxylic dianhydride used in the synthesis of polylysine, only a specific tetracarboxylic dianhydride may be used, or a specific tetracarboxylic acid may be used in combination. A compound other than dianhydride (hereinafter also referred to as "other tetracarboxylic dianhydride"). Examples of the other tetracarboxylic dianhydride which can be used in the methods [i] to [iii] include aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic acid II. Anhydride, etc.

Specific examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride and each of the following formulas (ar-6) to (ar-9). The compound represented, 1,2,5,6-hexanetetracarboxylic dianhydride, 1,1,2,2-ethylenetetracarboxylic dianhydride, a compound represented by the following formula (ar-I), The compound represented by the formula (ar-II) and the like; the alicyclic tetracarboxylic dianhydride may, for example, be 1,2,3,4-cyclobutanetetracarboxylic dianhydride or a 2,3,5-tricarboxyl ring. Amyl phthalic acid 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-8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphthalene And [1,2-c]furan-1,3-dione, 3-oxabicyclo[3.2.1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2', 5'-dione), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6 -Tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8 - dianhydride, 4,9-dioxatricyclo[5.3.1.0 ^2,6 ]undecane-3,5,8,10-tetraone, cyclohexane tetracarboxylic dianhydride, cyclopentane tetracarboxylate Acid dianhydride, 1,3 - dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, a compound represented by the following formula (ac-1) to formula (ac-30); aromatic tetracarboxylic acid Examples of the dianhydride include pyromellitic dianhydride, 4,4′-(hexafluoroisopropylidene)diphthalic anhydride, and each of the following formulas (ar-1) to (ar-5). The compound or the like can be used, and tetracarboxylic dianhydride or the like described in JP-A-2010-97188 can be used. In addition, the other tetracarboxylic dianhydride may be used alone or in combination of two or more.

(In the formula (ar-I) and the formula (ar-II), Z ¹ to Z ⁴ are each independently an alkanediyl group, an aliphatic ring, an aromatic ring or a heterocyclic ring having a carbon number of 1 to 20, and m3 to m5 are each independently It is 0 or 1. Among them, m3~m5 are not 0) at the same time.

[化18]

[Chemistry 19]

a divalent group represented by "-[Z ¹ ] _m3 -[Z ² ] _m4 -[Z ³ ] _m5 -" in the formula (ar-I), and Z in the formula (ar-II) ⁴ is preferably an alkanediyl group having a carbon number of 1 to 10, a phenyl group or a cyclohexyl group.

Specific examples of the compound represented by the above (ar-I) include compounds represented by the above formula (ar-6) and the following formula (ar-10) to formula (ar-12). Specific examples of the compound represented by the above (ar-II) include, for example, compounds represented by the following formulas (ar-13) and (ar-14).

The other tetracarboxylic dianhydride preferably contains a group selected from the group consisting of aromatic tetracarboxylic dianhydride and tetracarboxylic dianhydride having a nitrogen atom from the viewpoint of improving the electrical characteristics of the liquid crystal display device. At least one. When the aromatic tetracarboxylic dianhydride is used as the other tetracarboxylic dianhydride, the content ratio is preferably from 3 parts by weight to 90% based on 100 parts by weight of the total of the tetracarboxylic dianhydride used in the synthesis. The parts by weight are more preferably 5 parts by weight to 80 parts by weight.

As for the use of a tetracarboxylic dianhydride having a nitrogen atom as the other tetracarboxylic acid Preferable specific examples of the dianhydride include a compound represented by the formula (ar-I), a compound represented by the formula (ar-II), and the like. Among these, the compound represented by the formula (ar-6), the formula (ar-10) to the formula (ar-14) is more preferable, and the formula (ar-6) and the formula (ar-) are further more preferable. 13) The compound represented by the formula (ar-14) is particularly preferably a compound represented by the formula (ar-14).

In the case of using a tetracarboxylic dianhydride having a nitrogen atom as the other tetracarboxylic dianhydride, the content ratio thereof is preferably 3 mol with respect to the total 100 mol parts of the tetracarboxylic dianhydride used in the synthesis. Ears are ~80 moles, more preferably 5 moles to 70 moles.

Further, as the other tetracarboxylic dianhydride, tetracarboxylic dianhydride having a cyclobutane skeleton can be preferably used from the viewpoint of improving the photosensitivity by photodecomposition reaction, and it is more preferable to use 1, 2, 3, 4 - cyclobutane tetracarboxylic dianhydride and 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride. When a tetracarboxylic dianhydride having a cyclobutane skeleton is used as the other tetracarboxylic dianhydride, the content ratio of the tetracarboxylic dianhydride used in the synthesis is preferably 100 parts by mole. 5 parts or more, more preferably 10 mole parts or more.

In the case of the method of [i], from the viewpoint of sufficiently obtaining the effects of the present invention, the specific tetracarboxylic acid is specific to the total amount of the tetracarboxylic dianhydride used in the synthesis of polylysine. The use ratio of the acid dianhydride is preferably 50% by mole or more, more preferably 60% by mole or more, and still more preferably 70% by mole or more.

Moreover, the use of the specific tetracarboxylic dianhydride in the case of the method of [iii] with respect to the total amount of the tetracarboxylic dianhydride used in the synthesis of polylysine The ratio is preferably 30 mol% or more, more preferably 40 mol% or more, still more preferably 50 mol% or more.

In the case of using the tetracarboxylic dianhydride having the structure represented by the above formula (3), the use ratio thereof is preferably relative to the total amount of the tetracarboxylic dianhydride used in the synthesis of the polyamic acid. It is 1 mol% or more, more preferably 5 mol% or more, still more preferably 10 mol% or more. Further, the upper limit of the use ratio is not particularly limited, and can be arbitrarily set within a range of 100 mol% or less.

[specific diamine]

The specific diamine is a compound having the group represented by the formula (1) and two primary amino groups, and is represented, for example, by the following formula (b).

(In the formula (b), X ¹ is a sulfur atom, an oxygen atom or -NH-. R ⁸ and R ⁹ each independently represent a divalent organic group, and at least one of R ⁸ and R ⁹ has an aromatic ring." -CO- At least one of X ¹ -" is bonded to the aromatic ring)

Examples of the divalent organic group of R ⁸ and R ⁹ in the formula (b) include a hydrocarbon group having 1 to 30 carbon atoms, a hydrogen atom of the hydrocarbon group substituted with a halogen atom or the like, and a carbon group of the hydrocarbon group. The carbon keys include "-O-", "-S-", "-CO-", "-CO-O-", "-CO-S-", "-N=N-", etc. A base of a heterocyclic ring or the like. Preferable specific examples of the group "-R ⁸ -NH ₂ " and the group "-R ⁹ -NH ₂ " include a group represented by the following formula (b2). Further, the radical "-R ⁸ -NH ₂ " and the radical "-R ⁹ -NH ₂ " may be the same or different.

(In the formula (b2), A ¹ is a stretching phenyl group, a stretching phenyl group, a cyclohexylene group, a stretching cyclohexyl group, -A ³ -A ⁴ -** or -A ⁴ -A ³ -** (where A ³ is a phenyl group, A ⁴ is a cyclohexyl group, "**" means a bond with a primary amine group, and X ⁴ is -O-CO-* ⁴ , -S-CO-* ⁴ , -O- , -CO-O-* ⁴ , -CO-S-* ⁴ , -CO-, -N=N-, -C=C- or -C≡C- (where "* ⁴ " indicates bonding to A a bond at ¹ ). R ¹⁰ is a phenyl, anthracenyl, cyclohexyl or nitrogen-containing heterocyclic group, and these groups may have a substituent at the ring moiety. R ¹¹ is a carbon number of 1 to 20. a divalent chain hydrocarbon group or a divalent group containing "-O-" at a position adjacent to or adjacent to a carbon atom of the chain hydrocarbon group. R ¹² is a phenyl group, a naphthyl group or a cyclohexyl group. Further, the groups may have a substituent at the ring moiety. n4, n5 and n6 are each independently 0 or 1, and m2 is an integer of 0 to 2. wherein R ¹¹ is contained at a position adjacent to a carbon atom of the chain hydrocarbon group. In the case of the divalent group of "-O-", n4=n6=1. "*" indicates a binding bond)

As for the A ^{1 of} the formula (b2), from the viewpoint of improving the sensitivity to light, it is preferably a phenyl group or a phenyl group, and from the viewpoint of the alignment control force, it is preferably a cyclylene group, A ³ -A ⁴ -* or -A ⁴ -A ³ -*. X ⁴ is preferably -O-CO-* ⁴ , -S-CO-* ⁴ , -CO-O-* ⁴ or -CO-S-* ⁴ , more preferably -O-CO-* ⁴ or -S- CO-* ⁴ .

When the ring portion of R ¹⁰ and R ¹² has a substituent, the substituent may, for example, be a fluorine atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a carbon number of 1 ~3 fluoroalkyl and the like. The position of the substituent is not particularly limited, and when "-CO-O-", "-CO-S-" or "-CO-NH-" is bonded to the benzene rings of R ¹⁰ and R ¹² , it is preferred. It is ortho to "-CO-O-", "-CO-S-" or "-CO-NH-".

Regarding R ¹¹ , the description of R ⁶ in the formula (a2) can be applied.

Preferably, at least one of n4 and n6 is 1. The m2 is preferably 1 or 2 from the viewpoint of suitably exhibiting anisotropy by light irradiation, and is preferably 0 from the viewpoint of the alignment control force.

Preferable specific examples of the group represented by the formula (b2) include a group represented by each of the following formulas (b2-1) to (b2-26).

[Chem. 24]

(In the formula, "*" indicates a binding key.)

In the above-mentioned group, it is preferable that the group represented by the formula (b2) is represented by each of the formula (b2-24) to the formula (b2-26) from the viewpoint of the alignment control force of the liquid crystal molecules. Base.

Specific examples of the specific diamine include 4-aminophenyl-4'-aminobenzoate (a compound represented by the following formula (b-1)), and 3,3'-di. Methyl-4-aminophenyl-4'-aminobenzoate, 3,3',5,5'-tetramethyl-4-aminophenyl-4'-aminobenzoate Further, 3-methyl-4-aminophenyl-4'-aminobenzoic acid ester, a compound represented by each of the following formulas (b-2) to (b-42), and the like. In addition, one type of these may be used alone or two or more types may be used in combination.

[化29]

Among the diamines, a diamine having a structure of "-an aromatic ring-CO-X ¹ -aromatic ring-" is preferred in terms of high sensitivity to light, and specifically, the formula (b- 1), each of the compounds represented by the formula (b-3) to the formula (b-13), the formula (b-15) to the formula (b-20), and the formula (b-25) to the formula (b-27) . In addition, in the case where the alignment control force of the liquid crystal molecules is high, each of the compounds represented by the above formulae (b-28) to (b-38) is preferable.

[Other diamines]

In the case of the methods of [ii] and [iii], as the diamine used in the synthesis of polylysine, only the specific diamine may be used, or two other than the specific diamine may be used in combination. Amine (hereinafter also referred to as "other diamine"). Examples of the other diamine which can be used in the methods [i] to [iii] include an aliphatic diamine, an alicyclic diamine, an aromatic diamine, a diamine organodecane, and the like.

Specific examples of the aliphatic diamine include m-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, and hexamethylenediamine; Examples of the alicyclic diamine include 1,4-diaminocyclohexane, 4,4′-methylenebis(cyclohexylamine), and 1,3-bis(aminomethyl)cyclohexane; Examples of the aromatic diamine include p-phenylenediamine, 4,4'-extended ethyldiphenylamine, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenyl sulfide. , 5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl) Benzene, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminobenzene) Oxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(p-phenylenediisopropylidene)diphenylamine, 4,4' -(Interphenylene diisopropylidene) bisaniline, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2 ,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 3,6-diaminocarbazole, N-methyl -3,6-diaminocarbazole, N,N'-bis(4-aminophenyl)- Benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, 1,4-bis-(4-aminophenyl)-piperazine, dodecane Oxy-2,4-diaminobenzene, tetradecyloxy-2,4-diaminobenzene, octadecyloxy-2,5-diaminobenzene, cholesteryloxy-3 , 5-diaminobenzene, cholestyloxy-3,5-diaminobenzene, cholestyloxy-2,4-diaminobenzene, cholestyloxy-2,4 -diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanosteryl 3,5-diaminobenzoate , 3,6-bis(4-aminobenzimidyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxy Benzyl oxime)cyclohexyl-3,5-diaminobenzoic acid ester, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, {4- [2-(3,5-Diaminophenoxy)-ethoxy]-phenyl}-ethanone, 3,4-diaminobenzophenone, {4-[2-(3,5 -diaminophenoxy)-ethoxy]-phenyl}-phenyl-methanone, {4-[2-(2,4-diaminophenoxy)-ethoxy]-phenyl }-Phenyl-ketone, {4-[2-(2,4-diaminophenoxy)-ethoxy]-phenyl}-p-tolylmethyl-ketone, {4-[2 -(2,4- Diaminophenoxy)-ethoxy]-phenyl}-o-tolylmethyl ketone, 2,7-diaminofluorenone, 2,7-diamino fluorene, 9,9-double (4-Aminophenyl)anthracene, 3,5-diaminobenzoic acid, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 4,4'-diaminobiphenyl -3,3'-dicarboxylic acid, 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, 3,3'-diaminobiphenyl-4,4'-dicarboxylic acid, 3,3'-diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid, 4,4'-diamino group Biphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 4,4'-diaminodiphenylethane-3,3'-dicarboxylic acid, 4 , 4'-diaminodiphenylethane-3-carboxylic acid, 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid, and the following formula (b3-1)~( Each of the compounds represented by b3-14);

Examples of the diaminoorganomethoxy siloxane include 1,3-bis(3-aminopropyl)-tetramethyldioxane and 3,3'-[1,4-phenylene bis(dimethyl) Further, a diamine described in JP-A-2010-97188 can be used. As the other diamine, one of these may be used alone or two or more of them may be used alone or in combination. Used in combination.

In the case of the method of [ii], the diamine used in the synthesis of polylysine is used as a liquid crystal display element having a good sensitivity to light as a specific use ratio of the diamine. The total amount is preferably 30% by mole or more, more preferably 40% by mole or more, and still more preferably 50% by mole or more. Further, in the case of the method (iii), the use ratio of the specific diamine is preferably 20 mol% or more based on the total amount of the diamine used in the synthesis of the polyamic acid. More preferably, it contains 30 mol% or more, and still more preferably contains 40 mol% or more.

The content of the structure (Y) in the polymer (A) is preferably from 1 × 10 ^-5 mol / g to 1 × 10 ^-2 mol / g, more preferably from 5 × 10 ^-5 mol / g to 5 × 10 ^-3 mol/g. Therefore, it is preferable to set the type and amount of the specific tetracarboxylic dianhydride and the specific diamine to be used in such a manner that the content of the structure (Y) in the (A) polymer is within the above range.

The tetracarboxylic dianhydride and the diamine used in the reaction preferably contain a structure having a "-aromatic ring-CO-X1-aromatic ring-" from the viewpoint of improving the sensitivity of the (A) polymer to light. The diamine used in the reaction is preferably a tetracarboxylic dianhydride used for the reaction from the viewpoint of increasing photoreactivity (light absorbing property), and is preferably selected from the group consisting of a group consisting of the compound represented by the structure, the compound represented by the formula (a-5), the compound represented by the formula (a-28), and the compound represented by the formula (a-29) A combination of at least one of the groups. In this case, as the compound having the structure represented by the above formula (3), it is preferred to use the compound represented by the above formula (a-15) to formula (a-27), and the formula (ar-1)~ (ar-5) The compound shown and the like.

Further, the specific tetracarboxylic dianhydride and the specific diamine have the same effects in terms of obtaining a polyamic acid having a common structure (Y) in the main chain. Therefore, it can be used in the present invention even if it is not described in the following examples. Further, the same applies to other tetracarboxylic dianhydrides and other diamines used together with a specific tetracarboxylic dianhydride or a specific diamine, and it can be used in the present invention even if it is not described in the following examples.

[Molecular weight regulator]

In the case of synthesizing (A) polyglycolic acid, a terminal modified polymer can also be synthesized by using an appropriate molecular weight modifier (blocking agent) together with the tetracarboxylic dianhydride and the diamine as described above.

Examples of the molecular weight modifier include an acid monoanhydride, a monoamine compound, and a monoisocyanate compound. Specific examples of such acid anhydrides include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride, and positive examples. Cetyl succinic anhydride, 3-(3-trimethoxydecyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzo Furan-1,3-dione or the like; examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, 3-(three Fluoromethoxy)aniline, 4-(trifluoromethoxy)aniline, triethoxydecylalkylamine, 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 3 - Aminopropyl methoxy diethoxy decane or the like; examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

The ratio of use as a molecular weight regulator relative to the tetracarboxylic dianhydride used The total of 100 parts by mole of the diamine is preferably 20 mol parts or less, and more preferably 10 mol parts or less.

<Synthesis of polylysine>

The ratio of use of the tetracarboxylic dianhydride to the diamine in the synthesis reaction of the polyaminic acid to be used in the present invention is preferably such that the acid anhydride group of the tetracarboxylic dianhydride becomes 0.2 based on 1 equivalent of the amine group of the diamine. The ratio of the equivalent to 2 equivalents is more preferably a ratio of 0.3 equivalents to 1.2 equivalents.

The synthesis reaction of polylysine is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20 ° C to 150 ° C, and more preferably 0 ° C to 100 ° C. Further, the reaction time is preferably from 0.1 to 24 hours, more preferably from 0.5 to 12 hours.

Here, examples of the organic solvent include an aprotic polar solvent, a phenol solvent, an alcohol, a ketone, an ester, an ether, a halogenated hydrocarbon, a hydrocarbon, and the like. Specific examples of the organic solvent include, for example, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl. Examples of the phenol-based solvent include phenol, m-cresol, xylenol, and halogenated phenol; and the alcohol is, for example, methanol. Examples of the ketone include ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, and ethylene glycol monomethyl ether; and examples of the ketone include acetone, methyl ethyl ketone, and methyl isobutyl ketone; Ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, diethyl malonate, isoamyl propionate, isoamyl isobutyrate, etc.; examples of the ether include diethyl ether and diiso Pentyl ether, ethylene glycol methyl ether, ethylene glycol ether, ethylene glycol n-propyl ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ether Acetate, diethylene glycol dimethyl ether, tetrahydrofuran, etc.; halogenated hydrocarbons include, for example, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, etc. Examples of the hydrocarbon include hexane, heptane, octane, benzene, toluene, xylene, and the like.

Among these organic solvents, one or more selected from the group consisting of an aprotic polar solvent and a phenol solvent (the organic solvent of the first group) or one or more organic solvents selected from the first group are preferably used. And a mixture of one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons (the second group of organic solvents). In the latter case, the ratio of use of the organic solvent as the second group is preferably 50% by weight or less, more preferably, based on the total amount of the organic solvent of the first group and the organic solvent of the second group. It is 40% by weight or less, and more preferably 30% by weight or less. In addition, the amount (α) of the organic solvent used is preferably 0.1% by weight to 50% by weight based on the total amount (β) of the tetracarboxylic dianhydride and the diamine relative to the total amount of the reaction solution (α + β). .

The reaction solution in which polylysine was dissolved was obtained as described above. The reaction solution may be directly supplied to the preparation of the photo-aligning agent, or may be supplied to the photo-aligning agent after isolating the poly-proline contained in the reaction solution, or may be purified after the isolated polylysine is purified. Preparation of a photo-alignment agent. In the case where polylysine is subjected to dehydration ring closure to form a polyimine, the reaction solution may be directly supplied to a dehydration ring-closure reaction, or the polylysine contained in the reaction solution may be isolated and supplied to The dehydration ring closure reaction, or the isolated polylysine may be purified and supplied to the dehydration ring closure reaction. The isolation and purification of polylysine can be carried out in accordance with a known method.

<Polyurethane>

The polyglycolate (hereinafter also referred to as "(A) polyphthalate) which is the polymer of (A) of the present invention can be obtained, for example, by the following method: [I] by the synthesis reaction a method for synthesizing (A) a poly-proline acid with a hydroxyl group-containing compound, an acetal esterification agent, a halide, an epoxy group-containing compound, or the like, and [II] a tetracarboxylic acid diester and two A method of reacting an amine, [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine, and the like.

Here, examples of the hydroxyl group-containing compound used in the method [I] include alcohols such as methanol, ethanol, and propanol; and phenols such as phenol and cresol. Examples of the acetal esterification agent include N,N-dimethylformamide diethyl acetal and N,N-diethylformamide diethyl acetal. Further, examples of the halide include methyl bromide, ethyl bromide, stearyl bromide, methyl chloride, stearyl chloride, 1,1,1-trifluoro-2-iodoethane, and the like. Examples of the oxy group compound include propylene oxide and the like.

The tetracarboxylic acid diester used in the method [II] can be obtained, for example, by subjecting the tetracarboxylic dianhydride exemplified in the synthesis of the (A) polyproline to ring opening using the alcohol. The reaction of the tetracarboxylic acid diester with the diamine is preferably carried out in the presence of a suitable dehydration catalyst. Examples of the dehydration catalyst include 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium halide, carbonylimidazole, and phosphorus-based condensing agent.

The tetracarboxylic acid diester dihalide used in the method [III] can be obtained, for example, by reacting the tetracarboxylic acid diester obtained as described above with a suitable chlorinating agent such as sulfinium chloride.

In the method [II] and the method [III], the compound having the structure (Y) in at least one of tetracarboxylic dianhydride and diamine can be used, and the knot can be obtained. Poly(phthalate) of (Y). In addition, the polyglycolate may have only a phthalate structure, and may also be a partial ester compound in which a valeric acid structure and a phthalate structure coexist.

The reaction solution in which the polyphthalate was dissolved was obtained as described above. The reaction solution may be directly supplied to the preparation of the photo-aligning agent, or may be supplied to the photo-alignment agent after isolating the polyphthalate contained in the reaction solution, or may also be used for the isolated polyphthalate. After purification, it is supplied to the preparation of the photo-aligning agent. The isolation and purification of the polyglycolate can be carried out in accordance with a known method.

<polyimine]

The polyimine (hereinafter also referred to as "(A) polyimine)" which is a polymer (A) contained in the photo-aligning agent of the present invention can be obtained, for example, by synthesizing as described above. (A) Polyproline is subjected to dehydration ring closure to carry out hydrazine imidization.

The (A) polyimine may be a complete quinone imide formed by dehydration ring closure of the (A) polyaminic acid as a precursor thereof, or may be a proline structure. Only a part of the dehydration ring closure, the partial ruthenium imide of the proline structure and the quinone ring structure. As for the (A) polyimine, the sulfhydrylation ratio is preferably 5% or more, more preferably 10% to 60%, still more preferably 15% to 50%. The ruthenium iodization ratio is a ratio of the number of quinone imine ring structures of the polyimine to the total of the number of guanine structures and the number of quinone ring structures. Here, a part of the quinone imine ring may also be referred to as an isoindole ring.

The dehydration ring closure of polylysine is preferably carried out by a method of heating polylysine or dissolving polylysine in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst to the solution, if necessary The method of heating. Among them, the latter method is preferably used.

In the method of adding a dehydrating agent and a dehydration ring-closure catalyst to a solution of a polyamic acid to carry out hydrazine imidation, for example, an acid anhydride such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably from 0.01 mol to 20 mol per mol of the proline structure of the polyglycolic acid. As the dehydration ring-closing catalyst, for example, a tertiary amine such as pyridine, trimethylpyridine, dimethylpyridine or triethylamine can be used. The amount of the dehydration ring-closure catalyst used is preferably from 0.01 mol to 10 mol per mol of the dehydrating agent used. The organic solvent used for the dehydration ring-closure reaction is exemplified as an organic solvent exemplified as the organic solvent used in the synthesis of polyglycine. The reaction temperature of the dehydration ring closure reaction is preferably from 0 ° C to 180 ° C, more preferably from 10 ° C to 150 ° C. The reaction time is preferably from 1.0 to 120 hours, more preferably from 2.0 to 30 hours.

A reaction solution containing (A) polyimine was obtained as described above. The reaction solution may be directly supplied to the preparation of the photo-aligning agent, or may be supplied to the photo-aligning agent after removing the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution, or may be supplied to the photo-aligning agent after segregating the poly-imine. The preparation, or the isolated polyimine, can also be purified and supplied to the preparation of the photo-aligning agent. These purification operations can be carried out in accordance with a known method. In addition, the (A) polymer contained in the photo-alignment agent of the present invention may be used alone or in combination of two or more.

[(B) polymer]

The (B) polymer contained in the photoalignment agent of the present invention is at least one selected from the group consisting of polylysine, polyphthalate, and polyimine, and is polymerized with the (A). Different polymers. Setting the polymer component of the photo aligning agent only In the case of (A) a polymer, even when a decrease in voltage holding ratio or accumulation of residual charges occurs in the liquid crystal display element, it can be improved by blending different resins.

In the case where the (B) polymer is poly-proline (hereinafter also referred to as "(B) poly-proline), the (B) poly-proline may be, for example, a tetracarboxylic dianhydride. Obtained by diamine reaction. Here, as the tetracarboxylic dianhydride used for the synthesis of the (B) polymer, a compound exemplified as the tetracarboxylic dianhydride which can be used for the synthesis of the (A) polymer can be mentioned. Among them, from the viewpoint of suppressing the movement of charges in the molecule and between the molecules, it is preferred to contain an alicyclic tetracarboxylic dianhydride, and more preferably, it is selected from the group consisting of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, bicyclo [ 3.3.0] Octane-2,4,6,8-tetracarboxylic acid-2:4,6:8-dianhydride, 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-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, 1,2,3,4-ring At least one specific alicyclic tetracarboxylic dianhydride of the group consisting of butane tetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, and cyclohexane tetracarboxylic dianhydride.

The blending ratio of the specific alicyclic tetracarboxylic dianhydrides (the total amount thereof when two or more kinds are contained) is preferably the total amount of the tetracarboxylic dianhydride used in the synthesis. 30 mol% or more, more preferably 40 mol% or more.

The tetracarboxylic dianhydride used in the synthesis of the (B) polyproline may also contain a tetracarboxylic dianhydride (specific tetracarboxylic dianhydride) having the above structure (Y). As a ratio of use of a specific tetracarboxylic dianhydride, in order to introduce a sufficient amount of a component exhibiting characteristics different from specific tetracarboxylic dianhydride (for example, electrical properties or transparency), The total amount of the tetracarboxylic dianhydride used in the middle is preferably 30 mol% or less, and more preferably 20 mol% or less.

The diamine which can be used for the synthesis of (B) poly-proline is exemplified as a compound (specific diamine and other diamine) which can be exemplified as the diamine which can be used for the synthesis of the (A) polymer. In this case, the ratio of use of the specific diamine is preferably 30 mol% or less, and more preferably 20 mol% or less, based on the total amount of the diamine used in the synthesis.

Further, regarding the various reaction conditions in the synthesis of (B) polyglycine, the description of the (A) polymer can be applied. Further, the polyphthalate and the polyimine as the (B) polymer can also be obtained in accordance with the method described in the above (A) polymer. The (B) polymer to be contained in the photo-alignment agent of the present invention may be used alone or in combination of two or more.

(B) The polymer is preferably a polymer having a content ratio of at least one of a fluorine atom and a ruthenium atom (hereinafter also referred to as "specific atom") different from that of the (A) polymer. In general, it is known that when two kinds of polymers having different contents of specific atoms are blended, there is a phenomenon that a polymer having a high content of a specific atom tends to be present in an upper layer due to a difference in surface energy. A polymer having a low content of a specific atom is present in a lower layer. It is presumed that by using such a phenomenon, the content of the specific atom is different by using the (A) polymer and the (B) polymer, whereby each of the (A) polymer and the (B) polymer can be used. A deviation in distribution occurs in the liquid crystal alignment film.

When at least one of the (A) polymer and the (B) polymer has a specific atom (F, Si), the combination thereof may be, for example, the following forms [1] to [4].

[1] (A) The polymer and the (B) polymer have a specific atom, and the (A) polymer has a higher specific content ratio than the (B) polymer.

[2] (A) The polymer has a specific atom, and (B) the polymer does not substantially have a specific atomic morphology.

[3] (A) The polymer and (B) the polymer have a specific atom, and (B) the specific atom of the polymer has a higher content than the (A) polymer.

[4] (B) The polymer has a specific atom, and (A) the polymer does not substantially have a specific atomic morphology.

Among these forms, in order to appropriately control the alignment of the liquid crystal molecules, it is preferable that the content of the specific atom of the (A) polymer is higher than that of the (B) polymer. Specifically, it is preferably in the form of [1] or [2], and more preferably in the form of [2]. Further, the phrase "substantially does not have a specific atom" means that the specific unit does not have a specific atom, or the ratio of the repeating unit having a specific atom to all repeating units of the polymer is 1 mol% or less, preferably 0.5 mol. Less than the ear.

In order to obtain a polymer having a specific atom, for example, in the synthesis of a polymer, there may be mentioned: [i] a method of performing polymerization using a monomer containing a tetracarboxylic acid derivative having a specific atom; [ii] using a specific atom; a method of conducting polymerization of a monomer of a diamine; [iii] a method of performing polymerization using a monoamine having a specific atom as a blocking agent; [iv] performing polymerization using an acid monoanhydride having a specific atom as a blocking agent Method etc.

Here, examples of the tetracarboxylic acid derivative having a specific atom include 4,4′-(hexafluoroisopropylidene)diphthalic anhydride and an acid anhydride group-containing fluorenone oil (for example). The product name "X-22-2290AS" (manufactured by Shin-Etsu Chemical Co., Ltd.), etc.; as a diamine having a specific atom, for example, 4,4'-diamino-2,2'-bis(trifluoro) Methyl)biphenyl, 4,4'-diamino-3,3'-bis(trifluoromethyl)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl] Hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4-(4'-trifluoromethoxybenzylideneoxy)cyclohexyl-3,5-diaminobenzoic acid Acid ester, 1,3-bis(3-aminopropyl)-tetramethyldioxane, 3,3'-[1,4-phenylene bis(dimethylnonanediyl)] bis ( 1-propylamine) and the like; examples of the monoamine having a specific atom include 3-(trifluoromethoxy)aniline, 4-(trifluoromethoxy)aniline, triethoxydecylamine, and 3-amine. Propyltrimethoxydecane, 3-aminopropyltriethoxydecane, 3-aminopropylmethoxydiethoxydecane, etc.; as the acid monoanhydride having a specific atom, for example, 3- (3-trimethoxydecyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, etc. . Further, in order to obtain a polymer having a specific atom, one of the methods [i] to [iv] may be used, or two or more of them may be used in combination.

In the polymer having a specific atom, the content ratio of the repeating unit having a specific atom is preferably 70 mol% or less, more preferably 60 mol% or less, more preferably 60 mol% or less, relative to all repeating units of the polymer. It is 50% or less. Further, the lower limit is not particularly limited, and may be, for example, 1 mol% or more, and preferably 5 mol% or more.

. Structure (Z)

At least one of the (A) polymer and the (B) polymer preferably has a structure selected from the group represented by the following formula (2-1) and represented by the following formula (2-2) (wherein , except for the structure contained in the indole bond formed by the polymerization of the monomer) and the aza-containing At least one structure (Z) of the group formed by the rings. By introducing such a structure (Z) into the polymer, electrical characteristics such as voltage holding ratio or afterimage characteristics of the liquid crystal display element can be improved.

(In the formula (2-1), R ¹ is a halogen atom, an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms; r1 is an integer of 0 to 2, and r2 is 0 to 3; In the formula, "1" represents a bond. In the formula (2-2), R ² is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. "*2" indicates a bond. )

Examples of the alkyl group having 1 to 10 carbon atoms of R ¹ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, a decyl group and the like. These groups may be linear or branched. In addition, examples of the alkoxy group having a carbon number of 1 to 10 include a group in which an alkyl group having 1 to 10 carbon atoms is bonded to an oxygen atom, and specific examples thereof include a methoxy group and an ethoxy group. Propoxy and the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

R1 and r2 are each preferably 0 or 1.

The R ² is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group, and still more preferably a hydrogen atom.

Examples of the nitrogen-containing hetero ring include a piperidine ring, a pyrrolidine ring, a pyridine ring, a pyrazine ring, a piperazine ring, a pyrimidine ring, and a homopiperazine ring. Among them, a piperidine ring or a piperazine ring is preferred, and a piperidine ring is more preferred in that the effect of alleviating the accumulated residual charge is high.

The structure (Z) is preferably a structure represented by the above formula (2-2) or a nitrogen-containing hetero ring, and more preferably a nitrogen-containing hetero ring, from the viewpoint of having a high effect of improving electrical properties.

The structure (Z) can be introduced into any of the main chain or side chain of the polymer. Further, the polymer having the structure (Z) can be obtained, for example, by using a diamine having a carboxyl group in the synthesis of a polymer to obtain a polymer having the structure represented by the formula (2-1). Further, by using the diamine represented by each of the formula (b3-4) and the formula (b3-10) or the tetracarboxylic dianhydride represented by the formula (ar-1), the formula can be obtained. (2-2) A polymer of the structure shown. By using the formula (b-21), the formula (b3-1) to the formula (b3-3), the formula (b3-8), the formula (b3-9), the formula (b3-11) to the formula (b3- A polymer having a nitrogen-containing hetero ring can be obtained from each of the diamines represented by 14).

The polymer (A) and (B) may have the structure (Z), or only the (A) polymer may have the structure (Z), or only the (B) polymer may have the Structure (Z). In the coating film, one of the (A) polymer and the (B) polymer is preferred from the viewpoint of suitably utilizing the biasing of the (A) polymer and the (B) polymer from the viewpoint of the polarity of the use. The structure (Z) of the polymer is contained in a higher ratio than the other polymer, and it is more preferable that the other polymer does not substantially have the structure (Z). Preferably (B) the polymer has the structure (Z) form. In addition, "substantially does not have a structure (Z)" means that the structure (Z) does not have a structure, and the ratio of the repeating unit having the structure (Z) to all repeating units of the polymer is 1 mol%. Hereinafter, it is preferably 0.5 mol% or less.

In the polymer having the structure (Z), the content of the repeating unit having the structure (Z) is preferably from 2 mol% to 50 mol%, more preferably 5, relative to all repeating units of the polymer. Mole%~40% by mole.

The preferred combination of the polymer components of the photo-alignment agent of the present invention is, for example, the following forms [1] to [5].

[1] (A) The polymer is a polymer having a structure (Y) and a specific atom; (B) the polymer is a polymer having a structure (Z) and having a specific atom content lower than that of the (A) polymer. form.

[2] (A) The polymer is a polymer having a structure (Y), a structure (Z), and a specific atom; (B) a polymer having a structure (Z) and a specific atom content ratio (A) polymerization The morphology of the low polymer.

[3] (A) The polymer is a mixture of a polymer having a structure (Y) with a specific atom and a polymer having a structure (Y), a structure (Z), a specific atom; (B) a polymer having a structure (Z) And the form of the polymer having a specific atom content lower than that of the (A) polymer.

[4] (A) The polymer is a polymer having a structure (Y) and a structure (Z); (B) the polymer is a polymer having a structure (Y) and having a specific atom content higher than that of the (A) polymer. The shape of the object.

[5] (A) The polymer is a polymer having a structure (Y) and a structure (Z); (B) The polymer is a form of a polymer which does not substantially have a structure (Y) and has a specific atom content higher than that of the (A) polymer.

The combination of the (A) polymer and the (B) polymer is preferably a form of [1], [2] or [3], and more preferably a form of [1]. The reason for this is not necessarily clear, but it is presumed that when a coating film is formed on a substrate using the photo-aligning agent of the form of [1], the (A) polymer having high photoreactivity is biased toward the coating film. In the upper layer, the (B) polymer having a high effect of improving electrical properties is biased toward the lower layer. From this, it is estimated that excellent liquid crystal alignment properties and electrical characteristics are exhibited.

<Solid viscosity of polymer>

The (A) polymer and the (B) polymer preferably have a concentration of 10 m% when prepared as a solution having a concentration of 10% by weight. s~800mPa. The solution viscosity of s is more preferably 15 mPa. s~500mPa. s solution viscosity. Further, the solution viscosity (mPa.s) of the polymer is a concentration of 10% by weight prepared using a good solvent (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) for the polymer. The polymer solution was measured at 25 ° C using an E-type rotational viscometer.

The polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) of (A) polymer and (B) polymer is preferably 500 to 500,000, and more preferably 1,000 to 300,000.

The content ratio of the (A) polymer to the (B) polymer in the photo-aligning agent is preferably 2/8 to 8 in terms of a weight ratio (A/B) from the viewpoint of sufficiently obtaining the effect of the present invention. /2, more preferably 3/7~7/3.

<Other ingredients>

The photo-aligning agent of the present invention may contain other components as needed. Examples of the other component include a compound other than the above (A) polymer and (B) polymer, and a compound having at least one epoxy group in the molecule (hereinafter referred to as "epoxy group-containing compound"). ), a functional decane compound, a bismaleimide compound, an allyl group-containing compound, and the like.

[Other polymers]

The other polymers can be used to improve solution properties or electrical properties. Examples of the other polymer include polyester, polyamine, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene derivative, and poly(styrene-phenylmaleimide). Derivatives, poly(meth)acrylates, and the like.

In the case where another polymer is added to the photo-aligning agent, the compounding ratio is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, based on 100 parts by weight of all the amounts of the polymer in the composition.

[Epoxy group-containing compound]

The epoxy group-containing compound can be used to improve the adhesion or electrical properties of the liquid crystal alignment film to the surface of the substrate. Here, examples of the epoxy group-containing compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether. , neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromo neopentyl glycol condensate Glycerol ether, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N , N', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N-diglycidyl-benzylamine, N,N-diglycidyl-aminol a compound represented by each of the following formulas (e-1) to (e-9), a cyclohexane, N,N-diglycidyl-cyclohexylamine,

Sorbitol polyglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane polyglycidyl ether, hydroquinone diglycidyl ether, bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, Diglycidyl terephthalate or the like is a preferred compound. Further, as the epoxy group-containing compound, an epoxy group-containing polyorganosiloxane such as described in International Publication No. 2009/096598 can be used. In the case where the epoxy compound is added to the photo-aligning agent, the blending ratio is preferably a phase The total amount of the polymer contained in the photo-aligning agent is 40 parts by weight or less, and more preferably 0.1 parts by weight to 30 parts by weight.

[functional decane compound]

The functional decane compound can be used for the purpose of improving the printability of the photoalignment agent. Examples of such a functional decane compound include 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, and N-(2-aminoethyl)-3-aminopropyl Trimethoxy decane, N-triethoxydecyl propyl triethylidene triamine, N-benzyl-3-aminopropyltrimethoxy decane, N-phenyl-3-aminopropyl Trimethoxy decane, glycidoxymethyl trimethoxy decane, 3-glycidoxy propyl trimethoxy decane, and the like. In the case where the functional decane compound is added to the photo-aligning agent, the compounding ratio is preferably 2 parts by weight or less, more preferably 0.02 part by weight to 0.2 part by weight, per 100 parts by weight of the total of the polymer.

[Bismaleimide compound]

The bismaleimide compound can be used to improve the heat resistance or electrical properties of the liquid crystal alignment film and the abrasion resistance of the coating film. Examples of the bismaleimide compound include 4,4'-diphenylmethane bismaleimide and bis-(3-ethyl-5-methyl-4-maleimide phenylene). Methane, 2,2'-bis-[4-(4-maleimidophenoxy)phenyl]propane, 4-methyl-1,3-phenylene bismaleimide, under The compound represented by the formula (ad-2) and the like. In the case where the bismaleimide compound is added to the liquid crystal alignment agent, the compounding ratio is preferably 40 parts by weight or less, more preferably 0.1 parts by weight to 30 parts by weight based on 100 parts by total of the total of the polymer. Parts by weight.

[Allyl-containing compound]

The allyl group-containing compound can be used to improve electrical characteristics of the liquid crystal alignment film and to suppress a decrease in voltage holding ratio. Examples of the compound containing an allyl group include a compound represented by each of the following formulas (al-1) to (al-3). In the case of adding the allyl group-containing compound, the compounding ratio is preferably 40 parts by weight or less, more preferably 0.1 parts by weight to 30 parts by weight, per 100 parts by weight of the total of the polymer.

Further, as the other component, an additive which is usually added to the photo-aligning agent, for example, a compound having at least one oxetanyl group in the molecule, an antioxidant, a photosensitizer, or the like may be used in addition to the above components. Further, in order to increase the strength of the coating film, an indoleamine, a glutarinium compound, a hydroxypiperidone compound, and a piperidine compound described in Japanese Patent No. 3245849 may be added; Japanese Patent No. 5045241 Selected from the oxime, selected from oxetane, cyclosulfide At least one heterocyclic compound having a heterocyclic structure of a group consisting of ethane and oxazoline; inorganic particles having a particle diameter of 1,000 Å or less (for example, cerium oxide particles, etc.).

<solvent>

The liquid crystal alignment agent of the present invention is prepared as a liquid composition in which the polymer component and other components to be added as needed are preferably dispersed or dissolved in a suitable solvent.

Examples of the organic solvent to be used include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, and N,N-dimethyl group. Acetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, B Glycol methyl ether, ethylene glycol ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, two Ethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, Diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisoamyl ether, ethylene carbonate, propylene carbonate, and the like. These may be used alone or in combination of two or more.

The solid content concentration in the photo-aligning agent of the present invention (the ratio of the total weight of the components other than the solvent of the photo-aligning agent to the total weight of the photo-aligning agent) can be appropriately selected in consideration of viscosity, volatility, etc., and is preferably selected. It is in the range of 1% by weight to 10% by weight. In other words, the photo-aligning agent of the present invention can be applied to the surface of the substrate as described later, and it is preferable to form a coating film to be a liquid crystal alignment film by heating. In this case, when the solid content concentration is less than 1% by weight, The film thickness of the coating film becomes too small to be obtained Good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes too large, and it is difficult to obtain a favorable liquid crystal alignment film, and the viscosity of the photo-aligning agent is increased to deteriorate coating properties.

A particularly preferable range of the solid content concentration varies depending on the method used when the photo-aligning agent is applied onto the substrate. For example, in the case of using a spin coating method, it is particularly preferable to set the solid content concentration to a range of 1.5% by weight to 4.5% by weight. In the case of using the printing method, it is particularly preferable to set the solid content concentration to a range of 3% by weight to 9% by weight, thereby setting the solution viscosity to 12 mPa. s~50mPa. The scope of s. In the case of using the inkjet method, it is particularly preferable to set the solid content concentration to a range of 1% by weight to 5% by weight, thereby setting the solution viscosity to 3 mPa. s~15mPa. The scope of s. The temperature at which the photo-aligning agent of the present invention is prepared is preferably from 10 ° C to 50 ° C, more preferably from 20 ° C to 30 ° C.

<Liquid alignment film>

The liquid crystal alignment film in the present invention can be formed using the photoalignment agent prepared as described above. The liquid crystal alignment film is preferably used in a liquid crystal display device of a TN type, an STN type or a transverse electric field type. Among them, in particular, it is preferably applied to a liquid crystal display device of a transverse electric field type such as an IPS type or an FFS type, so that the effect of reducing the remaining marks of the liquid crystal display element can be maximized.

The liquid crystal alignment film in the present invention can be produced by a method comprising the steps of: a film forming step of applying the photo-aligning agent of the present invention onto a substrate to form a coating film; and a light irradiation step of performing light on the formed coating film. The liquid crystal alignment film is formed by irradiation.

[Film formation step]

In this step, the photo-aligning agent of the present invention is applied onto a substrate, and secondly, a coating film is formed on the substrate by heating the coated surface.

When applied to a TN type or STN type liquid crystal display element, two sheets of a substrate having a patterned transparent conductive film are used as a pair, and the light alignment of the present invention is applied to the formation surface of each of the transparent conductive films. A coating film is formed by the agent. On the other hand, in the case of being applied to a liquid crystal display device of a lateral electric field type, a substrate having an electrode on one side (the electrode includes a patterned transparent conductive film or a metal film) and an opposite substrate not provided with an electrode As a pair, the photo-aligning agent of the present invention is applied to each of the surface on which the electrode is formed and the surface of the counter substrate to form a coating film.

In any case, the substrate may be, for example, glass such as float glass or soda glass; transparent plastic containing polyethylene terephthalate, polybutylene terephthalate, polyether oxime, polycarbonate, or the like. Substrate, etc. As the transparent conductive film, for example, using indium tin containing In ₂ O ₃ -SnO ₂ oxide (Indium Tin Oxide, ITO) film, comprising SnO Naise (NESA) ₂ (registered trademark) film. As the metal film, for example, a film containing a metal such as chromium can be used. For the patterning of the transparent conductive film and the metal film, for example, a method of forming a pattern by a photolithography method, a sputtering method, or the like after forming a transparent conductive film having no pattern, and a pattern having a desired pattern when forming a transparent conductive film can be used. The method of masking, etc. Further, when the photo-aligning agent is applied, in order to improve the adhesion between the substrate, the conductive film or the electrode and the coating film, the surface on which the coating film is formed on the surface of the substrate may be coated with a functional decane compound or a functional titanium. Pretreatment of compounds and the like.

Coating the photo-aligning agent on the substrate can preferably be performed by offset printing or spin coating. It is carried out by a coating method such as a roll coater method or an inkjet printing method. After the application of the photo-aligning agent, it is preferable to carry out preheating (pre-baking) (pre-baking step) for the purpose of preventing dripping of the applied photo-aligning agent. The prebaking temperature is preferably from 30 ° C to 200 ° C, more preferably from 40 ° C to 150 ° C, and particularly preferably from 40 ° C to 100 ° C. The prebaking time is preferably from 0.25 minutes to 10 minutes, more preferably from 0.5 minutes to 5 minutes. Thereafter, the solvent is completely removed, and a post-baking step is carried out as needed, that is, the pre-baked coating film is fired for the purpose of thermally imidating the proline structure present in the polymer. The post-baking temperature at this time is preferably 80 ° C to 300 ° C, and more preferably 120 ° C to 250 ° C. The post-baking time is preferably from 5 minutes to 200 minutes, more preferably from 10 minutes to 100 minutes. The film thickness of the coating film after post-baking is preferably 0.001 μm to 1 μm, and more preferably 0.005 μm to 0.5 μm.

[Light irradiation step]

In this step, the liquid crystal alignment ability is imparted by irradiating the coating film formed on the substrate with polarized or non-polarized radiation. As the radiation, for example, ultraviolet light and visible light including light having a wavelength of 150 nm to 800 nm can be used. In the case where the radiation is polarized, it can be said that the linearly polarized light may also be partially polarized. Further, when the radiation to be used is linearly polarized or partially polarized, the irradiation may be performed from a direction perpendicular to the substrate surface, or may be performed from an oblique direction, or may be performed in combination. When the non-polarized radiation is irradiated, the direction of the irradiation is set to an oblique direction.

As the light source to be used, for example, a low pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser or the like can be used. The preferred wavelength region of ultraviolet light can be obtained by passing the light source with, for example, a filter, a diffraction grating (diffraction grating) and the like are used in combination.

The light irradiation can be carried out by the following methods: [1] a method of irradiating the coating film after the post-baking step, [2] a method of irradiating the coating film before the pre-baking step and the post-baking step, [ 3] A method of irradiating a coating film in heating of a coating film in at least any of a prebaking step and a post baking step. The method of [2] is preferable in that the effect of reducing the mark of the liquid crystal display element is high. Light irradiation amount is preferably ^{100J / m 2 ~ 50,000J / m} 2, and more preferably ^{300J / m 2 ~ 20,000J / m} 2. Further, in order to improve the reactivity, it is also possible to perform light irradiation on the coating film while heating the coating film. The temperature at the time of heating is usually from 30 ° C to 250 ° C, preferably from 40 ° C to 200 ° C, more preferably from 50 ° C to 150 ° C. A liquid crystal alignment film is formed on the substrate as described above.

<Liquid crystal display element>

The liquid crystal display element of the present invention comprises the liquid crystal alignment film obtained above. The liquid crystal display element of the present invention can be produced, for example, as follows. First, a pair of substrates in which a liquid crystal alignment film is formed as described above is prepared, and a liquid crystal cell having a liquid crystal sandwiched between the pair of substrates is manufactured. The following two methods are exemplified for the production of the liquid crystal cell. The first method is a conventionally known method. First, the two liquid crystal substrates are opposed to each other so that the two substrates are opposed to each other, and the peripheral portions of the two substrates are bonded together with a sealant, and are separated from the surface of the substrate and the sealant. After filling the liquid crystal into the cell gap, the injection hole is sealed, thereby manufacturing a liquid crystal cell.

The second method is called the One Drop Fill (ODF) method. First, for example, an ultraviolet light-curable sealant is applied to a predetermined position on one of the substrates, and further, after liquid crystal is dropped on the liquid crystal alignment film surface, the liquid crystal alignment film pair is used. The other substrate is bonded to the other, and the entire surface of the substrate is irradiated with ultraviolet light to harden the sealing agent, thereby manufacturing a liquid crystal cell. In the case of using any method, it is preferable to heat the liquid crystal cell to a temperature at which the liquid crystal to be used becomes an isotropic phase, and then gradually cool to room temperature, thereby removing the flow alignment during liquid crystal filling. Next, a polarizing plate is bonded to the outer surface of the liquid crystal cell, whereby the liquid crystal display element of the present invention can be obtained. Further, when the radiation is linearly polarized, the two substrates on which the liquid crystal alignment film is formed can be obtained by appropriately adjusting the angle formed by the polarization direction of the irradiated radiation and the angle between each substrate and the polarizing plate. Liquid crystal display element.

As the sealant, for example, an epoxy resin containing an alumina ball as a spacer and a curing agent can be used.

As the liquid crystal, for example, a nematic liquid crystal, a smectic liquid crystal, or the like can be used. Among them, a liquid crystal having a positive dielectric anisotropy of a nematic liquid crystal is preferably used, and for example, a biphenyl liquid crystal or a phenyl ring can be used. A hexane liquid crystal, an ester liquid crystal, a terphenyl liquid crystal, a biphenyl cyclohexane liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, a bicyclooctane liquid crystal, a cuba liquid crystal, or the like. Further, for example, a cholesteric liquid crystal such as cholesteryl alcohol, cholesteryl phthalate or cholesteryl carbonate may be further added to the liquid crystal; as the trade names "C-15" and "CB-15" ( A chiral agent commercially available from Merck & Co., Ltd.; a ferroelectric liquid crystal such as p-methoxybenzylidene-p-amino-2-methylbutylcinnamate.

The polarizing plate may be a polarizing film called a "H film" sandwiched between a cellulose acetate protective film (the H film is one side which allows the polyvinyl alcohol to be extended to absorb iodine on one side. A polarizing film made of a polarizing film or a polarizing plate including the H film itself.

Since the liquid crystal display element of the present invention includes the liquid crystal alignment film formed by the photoalignment method using the photoalignment agent of the present invention, in particular, when applied to a liquid crystal display device of a lateral electric field type, the trace is small and the display is small. A high voltage retention rate. Therefore, the liquid crystal display element of the present invention can be effectively applied to various devices, for example, as a clock, a portable game machine, a word processor, a notebook computer, a car navigation system, a camcorder, a personal digital assistant. A liquid crystal display element used in a display device such as a (Personal Digital Assistant, PDA), a digital camera, a mobile phone, a smart phone, various displays, a liquid crystal television, or an information display is suitably used.

[Examples]

Hereinafter, the present invention will be more specifically described by the examples, but the present invention is not limited by the examples.

The weight average molecular weight of each polymer in the synthesis example, the solution viscosity of each polymer solution, and the oxime imidization ratio can be measured by the following methods.

[weight average molecular weight of polymer]

The weight average molecular weight Mw of the polymer is a polystyrene equivalent value measured by gel permeation chromatography under the following conditions.

Pipe column: manufactured by Tosoh Corporation, TSKgelGRCXLII

Solvent: tetrahydrofuran

Temperature: 40 ° C

Pressure: 68kgf/cm ²

[Solid viscosity of polymer solution]

Solution viscosity of polymer solution [mPa. s] was measured using a T-type rotational viscometer at 25 ° C using a solution prepared by using N-methyl-2-pyrrolidone (NMP) at a polymer concentration of 10% by weight.

[Determination of sulfhydrylation rate]

The solution of the polyimine is put into pure water, and the obtained precipitate is sufficiently dried under reduced pressure at room temperature, and then dissolved in deuterated dimethyl hydrazine, and measured at room temperature with tetramethyl decane as a reference substance. ¹ H- NMR ^{(1 H-Nuclear magnetic resonance,} 1 H-NMR). From the obtained ¹ H-NMR spectrum, the oxime imidization ratio [%] was determined from the formula represented by the following formula (1).

醯imination rate [%]=(1-A ¹ /A ² ×α)×100...(1)

(In the formula (1), A ¹ is the peak area of the proton derived from the NH group appearing near the chemical shift of 10 ppm, A ² is the peak area derived from other protons, and α is the precursor of the polymer (polyamide) The ratio of the number of other protons in the acid to the proton of one NH group)

"Synthesis of Polymers"

The polymer (A-1) to the polymer (A-14) and the polymer (B-1) to the polymer (B-7) were synthesized in the respective synthesis examples using the following compounds.

<tetracarboxylic acid derivative>

. Specific tetracarboxylic dianhydride

. Other tetracarboxylic dianhydrides and tetracarboxylic acid diesters

(In the formula (t-6), R is an ethyl group. In the formula (t-12), m is an integer of 1 to 15.)

<Diamine>

. Specific diamine

[化37]

. Other diamines

[化38]

<monoamine>

<(A) Synthesis of Polymer>

. Synthesis of polyimine

[Synthesis Example a1: Synthesis of Polymer (A-1)]

100 parts of the compound (a-2) as the tetracarboxylic dianhydride, 70 parts of the compound (b-1) as a diamine, and 30 parts of the compound (d-7) are dissolved in the N-methyl group. In 2-pyrrolidone (NMP), it was reacted at room temperature for 6 hours. Thus, a polyaminic acid solution having a solid concentration of 15% was obtained. Secondly, in the obtained polyaminic acid solution In the above, N-methylpiperidine and acetic anhydride were added in an amount of 0.5 times by mole based on the amount of tetracarboxylic dianhydride used, and a dehydration ring-closure reaction was carried out at 75 ° C for 3 hours. After the dehydration ring closure, the solvent in the system was subjected to solvent replacement with a new NMP to obtain a polyimine solution containing 15% by weight of a ruthenium iodide ratio of 30%. This polyimine was used as the polymer (A-1). The weight average molecular weight Mw of the polymer (A-1) was 50,000.

[Synthesis Example a7: Synthesis of Polymer (A-7)]

The same procedure as in Synthesis Example a1 was carried out except that the type and amount of the tetracarboxylic dianhydride and the diamine used were changed as shown in the following Table 1, and a polyimine having a ruthenium imidization ratio of 35% was synthesized. . The obtained polyimine was used as the polymer (A-7). The weight average molecular weight Mw of the polymer (A-7) was 80,000.

[Synthesis Example a10: Synthesis of Polymer (A-10)]

The synthesis example a1 was carried out except that the type and amount of the tetracarboxylic dianhydride and the diamine to be used were changed as in the following Table 1, and the molar amount of the compound (m-1) as a monoamine was 20 mol parts. In the same operation, a polyimine having a ruthenium imidization ratio of 20% was synthesized. The obtained polyimine was used as the polymer (A-10). The weight average molecular weight Mw of the polymer (A-10) was 95,000.

. Synthesis of polyaminic acid

[Synthesis Example a2: Synthesis of Polymer (A-2)]

50 mol parts of the compound (a-2) as a tetracarboxylic dianhydride, 40 mol parts of the compound (a-15), and 10 mol parts of the compound (a-12), a compound (b- as a diamine) 5) 80 mol parts, and 20 mol parts of the compound (d-8) were dissolved in NMP, and the reaction was carried out for 8 hours at room temperature. Thus, a polyglycine having a solid concentration of 15% was obtained. Solution. The obtained poly-proline was used as the polymer (A-2). The weight average molecular weight Mw of the polymer (A-2) was 40,000.

[Synthesis Example a4 to Synthesis Example a6, Synthesis Example a8, Synthesis Example a14: Synthesis of Polymer (A-4) to Polymer (A-6), Polymer (A-8), and Polymer (A-14) ]

The same procedure as in Synthesis Example a2 was carried out except that the type and amount of the tetracarboxylic dianhydride and the diamine used were changed as shown in the following Table 1, and a polyamine acid solution having a solid concentration of 10% was obtained. The weight average molecular weight Mw of each polymer is shown together in Table 1 below.

[Synthesis Example a9, Synthesis Example a11: Synthesis of Polymer (A-9), Polymer (A-11)]

In addition to the type and amount of the tetracarboxylic dianhydride and the diamine to be used, as shown in the following Table 1, and the addition of the compound (m-1) or the compound (m-2) as a monoamine, In the same manner as in Synthesis Example a2, a polyamic acid solution having a solid concentration of 10% was obtained. The weight average molecular weight Mw of each polymer is shown together in Table 1 below.

. Synthesis of polyglycolate

[Synthesis Example a3: Synthesis of Polymer (A-3)]

70 mol parts of the compound (t-3) as tetracarboxylic dianhydride, and 30 mol parts of the compound (t-8), 90 mol parts of the compound (b-10) as a diamine, and a compound (d- 8) 10 moles were dissolved in NMP and allowed to react at room temperature for 6 hours. Further, 80 parts of N,N-dimethylformamide diethyl acetal was added dropwise to the reaction liquid, followed by a reaction at 50 ° C for 2 hours to obtain a polyamidate solution. Weight of polymer (A-3) The average molecular weight is 120,000.

[Synthesis Example a12: Synthesis of Polymer (A-12)]

30 g of the compound (t-5) as a tetracarboxylic dianhydride was added to 500 mL of ethanol to prepare a tetracarboxylic acid diester. The obtained precipitate was separated by filtration, washed with ethanol, and dried under reduced pressure to give a tetracarboxylic acid diester powder. After the obtained tetracarboxylic acid diester (compound (t-6)) 15 mol parts, the compound (a-2) 70 mol parts, and the compound (t-11) 15 mol parts are dissolved in NMP, The compound (b-10) as a diamine was added thereto in an amount of 100 parts by mol. To this solution was added 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholine hydrochloride (DMT-MM, 15% by weight ± 2) Weight % hydrate) 300 moles, reacted at room temperature for 4 hours to obtain a polyamidate solution. The weight average molecular weight Mw of the polymer (A-12) was 40,000.

[Synthesis Example a13: Synthesis of Polymer (A-13)]

The same procedure as in Synthesis Example a12 was carried out except that the type and amount of the tetracarboxylic acid diester, the tetracarboxylic dianhydride, and the diamine used were changed as shown in the following Table 1, and a polyamine having a solid concentration of 10% was obtained. Acid solution. The weight average molecular weight Mw of the polymer (A-13) was 65,000.

<(B) Synthesis of Polymer>

[Synthesis Example b1 to Synthesis Example b7: Synthesis of Polymer (B-1) to Polymer (B-7)]

The same procedure as in Synthesis Example a2 was carried out, except that the type and amount of the tetracarboxylic dianhydride and the diamine used were changed as shown in the following Table 2, to obtain a polyaminic acid solution having a solid concentration of 10%. The weight average molecular weight Mw of each polymer is expressed together Table 2 below.

In Tables 1 and 2, the numerical values in parentheses in each column of the compound are ratios (molar parts) indicating a total of 100 moles with respect to the total amount of the tetracarboxylic acid derivative to be used.

[Example 1]

<Preparation of photo-aligning agent>

NMP was added to a solution containing 50 parts by weight of the polymer (A-1) obtained in the Synthesis Example 1 as a polymer component and 50 parts by weight of the polymer (B-1) obtained in Synthesis Example 15. The butyl cellosolve (BC) was thoroughly stirred to prepare a solution having a solvent composition of NMP: BC = 70:30 (weight ratio) and a solid concentration of 3.0% by weight. The solution was filtered using a filter having a pore size of 0.45 μm, thereby preparing a photo-aligning agent.

<Manufacture of liquid crystal display element>

A glass substrate including a metal electrode (electrode A and electrode B) of a two-system system including chromium in a comb shape is provided, and a voltage can be independently applied to the electrodes A and B. The glass substrate and the counter-glass substrate on which the electrode was not provided were used as a pair, and the prepared photo-alignment agent was applied to one surface of the glass substrate having the electrode and one surface of the counter-glass substrate, respectively, using a rotator. Next, prebaking was performed for 1 minute using a hot plate at 80 ° C, and thereafter, using Hg-Xe lamps and Glan-Taylor Prisms, the side of the substrate was coated with the photo-alignment agent in the vertical direction from the substrate surface. The surface of the substrate was irradiated with polarized ultraviolet rays of 10,000 J/m ² . After the light irradiation, heating (post-baking) was performed at 200 ° C for 1 hour in an oven in which the inside of the tank was purged with nitrogen. Thus, a pair of substrates including a liquid crystal alignment film having a film thickness of 0.1 μm were obtained.

Next, an epoxy resin adhesive having an alumina ball having a diameter of 3.5 μm is applied to the outer periphery of a surface of the pair of substrates having one liquid crystal alignment film by screen printing, and the liquid crystal alignment of the pair of substrates is performed. The film was faced to face, and the substrates were superposed so as to overlap each other when the polarized ultraviolet rays were irradiated, and the adhesive was thermally cured at 150 ° C for 1 hour. Next, the liquid crystal injection port was filled with a liquid crystal "MLC-7028" manufactured by Merck from the gap between the substrates, and the liquid crystal injection port was sealed with an epoxy adhesive. In order to remove the flow alignment at the time of liquid crystal injection, it was further heated at 150 ° C and then slowly cooled to room temperature. Then, the polarizing plate is bonded to the two surfaces on the outer side of the substrate so that the polarizing directions of the polarizing plates are orthogonal to each other and the optical axis of the polarized ultraviolet light of the liquid crystal alignment film is perpendicular to the projection direction of the substrate surface. Liquid crystal display element. Further, by performing the series of operations by changing the amount of ultraviolet irradiation before the prebaking, it is possible to manufacture three or more liquid crystal display elements having different amounts of ultraviolet irradiation.

<Evaluation of Liquid Crystal Display Element>

The following evaluations (1) to (5) were carried out using the liquid crystal display element produced as described above. In addition, in the following (2) to (4), the most suitable sensitivity is selected from three or more liquid crystal display elements having different ultraviolet irradiation amounts based on the results of the evaluation of the sensitivity in the same manner as (1). The evaluation result of the liquid crystal display element which is most suitable for sensitivity.

(1) Evaluation of sensitivity to ultraviolet rays

Using the liquid crystal display element produced as described above, the presence or absence of an abnormal region in the change in brightness and darkness when a voltage of 5 V was applied/released was observed with an optical microscope. It can be said that the smaller the amount of ultraviolet irradiation when the liquid crystal alignment property is observed (when an abnormal region is not observed), the better the sensitivity of the coating film to ultraviolet rays. As the evaluation, was not observed in any case where the amount of ultraviolet radiation to the abnormal region sensitivity as "good", the abnormality was observed in the region of 5,000 J / m ² ultraviolet irradiation amount, but 7,000J / m ² and When no abnormal region was observed at an ultraviolet irradiation amount of 10,000 J/m ² , the sensitivity was "acceptable", and an abnormal region was observed at an ultraviolet irradiation amount of 5,000 J/m ² and 7,000 J/m ² as a sensitivity. "failed".

(2) Evaluation of voltage retention rate

Using the liquid crystal display element produced, a voltage of 5 V was applied at 60 ° C for an application time of 60 μsec and a span of 167 msec, and then the voltage holding ratio after 167 msec from the application release was measured. The measuring device used "VHR-1" manufactured by Dongyang Technology Co., Ltd. The liquid crystal display element has a voltage holding ratio of 99%.

(3) Determination of charge accumulation amount (RDC)

Using the manufactured liquid crystal display element, the dielectric absorption method is used to determine After a DC voltage of 2 V was applied for 10 minutes at 71 ° C, a short circuit was performed for 0.2 seconds, and thereafter, the voltage accumulated in the liquid crystal display element at the time of the open state for 10 minutes was maintained. In the evaluation, the case where the amount of charge accumulation is 0.1 V or less is regarded as "good (?)", and when the amount of charge accumulation is more than 0.1 V and is 0.2 V or less, "can be (○)", and the amount of charge accumulation is more than 0.2. The case of V is "bad (△)". As a result, the evaluation of the amount of charge accumulation of the liquid crystal display element is acceptable.

(4) Evaluation of AC afterimage characteristics

The AC afterimage characteristics (marking characteristics) were evaluated using the manufactured liquid crystal display element. First, the liquid crystal display element was placed in an environment of 25 ° C and 1 atm, and a voltage of 4 V was applied to the electrode A without applying a voltage to the electrode B. Immediately thereafter, an alternating voltage of 4 V was applied to both of the electrode A and the electrode B. The time from the time when the 4 V alternating voltage was applied to the two electrodes was started until the difference in the light transmittance between the electrodes A and B was not visually confirmed. When the time is less than 60 seconds, the retention characteristic is "good (?)". When the time is 60 seconds or more and less than 100 seconds, the retention characteristic "(可)" is used as the retention characteristic. In the case of 100 seconds or more, it is "failed (x)" as a mark. As a result, the retention characteristic of the liquid crystal display element is "fair".

(5) Evaluation of contrast after driving pressure

After the manufactured liquid crystal display element was driven for 30 hours with an AC voltage of 10 V, a polarizer and an analyzer were placed between the light source and the light amount detector, and the following mathematical expression was measured. (2) The minimum relative transmittance (%) indicated.

Minimum relative transmittance (%) = (β - B ⁰ ) / (B ¹⁰⁰ - B ⁰ ) × 100 (2)

(In the mathematical formula (2), B ⁰ is the transmission amount of light under the blank crossed Nicol prism. B ¹⁰⁰ is the transmission amount of light under the blank opposite Nicol. prism is positive. Under the Nicol prism, the liquid crystal display element is sandwiched between the polarizer and the analyzer to achieve the minimum amount of light transmission)

The black level of the dark state is represented by the minimum relative transmittance of the liquid crystal display element, and the smaller the black level in the dark state, the more excellent the contrast. The case where the minimum relative transmittance is less than 0.5% is regarded as "good", and the case where 0.5% or more and less than 1.0% is used is "fair", and the case of 1.0% or more is regarded as "bad". As a result, the contrast evaluation of the liquid crystal display element was judged as "good".

[Example 2, Example 6 to Example 10, Example 12, Example 13, Example 14, Comparative Example 1 to Comparative Example 3]

A photoalignment agent was prepared in the same manner as in Example 1 except that the type of the polymer to be used was changed as shown in the following Tables 3 and 4, and a liquid crystal display device was produced. Further, various evaluations of the manufactured liquid crystal display elements were performed. The evaluation results are shown in Tables 3 and 4 below, respectively.

[Example 3 to Example 5, Example 11, Example 15]

A liquid alignment element was produced in the same manner as in Example 1 except that the type of the polymer to be used and the type of the additive were changed as shown in the following Tables 3 and 4, respectively, to produce a liquid crystal display element. Moreover, the manufacture is carried out Various evaluations of liquid crystal display elements. The evaluation results are shown in Tables 3 and 4 below, respectively.

In Tables 3 and 4, the values in the column of the amount of the polymer indicate the respective polymer phases. The blending ratio (parts by weight) of 100 parts by weight of the total of the polymers used in the preparation of the photoalignment agent. The names of the additives are as follows.

[additive]

Q-1: N, N, N', N'-tetraglycidyl-4,4'-diaminodiphenylmethane (compound (Q-1) below)

Q-2: The following compound (Q-2)

As shown in Tables 3 and 4, in Examples 1 to 13, the voltage holding ratio was 99% or more, and the amount of charge accumulation was also small. Further, the AC afterimage characteristics, the contrast characteristics, and the sensitivity to ultraviolet rays are "good" or "fair", and a balance of various characteristics is obtained. Further, the same results were obtained in Example 14 and Example 15. On the other hand, in Comparative Example 1 to Comparative Example 3, the voltage holding ratio was lower than 99%, and the amount of charge accumulation was also large.

<(A) Synthesis of Polymers [2]>

The same procedure as in the synthesis example a2 was carried out except that the type and amount of the tetracarboxylic dianhydride and the diamine used were changed as shown in the following Table 5, and a polyamic acid solution having a solid concentration of 10% by weight was obtained. . The weight average molecular weight Mw of each polymer is shown together in Table 5 below.

In Table 5, the numerical values in parentheses in each column of the compound are ratios (molar parts) indicating a total of 100 moles with respect to the total amount of the tetracarboxylic acid derivative to be used.

<Preparation of optical alignment agent and manufacture and evaluation of liquid crystal display element [2]>

[Example 16 to Example 21]

A photoalignment agent was produced in the same manner as in Example 1 except that the type of the polymer to be used was changed as shown in the following Table 6, and a liquid crystal display device was produced. Further, various evaluations of the manufactured liquid crystal display elements were performed. The evaluation results are shown in Table 6 below.

In Table 6, the numerical value in the column of the amount of the polymer indicates the blending ratio (parts by weight) of 100 parts by weight of the total of the polymer used in the preparation of the photo-aligning agent.

As shown in Table 6, in Examples 16 to 21, the voltage holding ratio, the charge accumulation amount, the AC afterimage characteristics, the contrast characteristics, and the sensitivity to ultraviolet rays were all evaluated as "good" or "fair". Balance of various characteristics.

Claims (14)

A method for producing a liquid crystal alignment film, comprising the steps of: applying a liquid crystal alignment agent on a substrate to form a coating film, wherein the liquid crystal alignment agent comprises (A) a polymer and (B) a polymer selected from the group consisting of At least one polymer component of the group consisting of lysine, polyphthalate, and polyimine, and the (A) polymer has a structure represented by the following formula (1) in the main chain ( Y) (wherein, in the case where X ¹ is -NH-, except for a guanamine bond formed by a polymerization reaction); a step of subjecting the coating film to light irradiation to form a liquid crystal alignment film; (In the formula (1), X ¹ is a sulfur atom, an oxygen atom or -NH-; "*" represents a bond, respectively; wherein at least one of the two "*"s is bonded to the aromatic ring). The method for producing a liquid crystal alignment film according to claim 1, wherein a content ratio of at least one specific atom of a fluorine atom and a ruthenium atom is different between the (A) polymer and the (B) polymer. . The method for producing a liquid crystal alignment film according to claim 2, wherein the specificity of the (A) polymer is compared with the (B) polymer The atomic content is high. The method for producing a liquid crystal alignment film according to claim 2, wherein in the polymer having the specific atom, all repeats of the repeating unit having the specific atom with respect to the polymer The content of the unit is from 1 mol% to 70 mol%. The method for producing a liquid crystal alignment film according to the above aspect, wherein the ratio of the (A) polymer to the (B) polymer is in a weight ratio (A/B). The words are 2/8~8/2. The method for producing a liquid crystal alignment film according to claim 1 or 2, wherein at least any one of the (A) polymer and the (B) polymer has a formula selected from the group consisting of 2-1) the structure represented by the following formula (2-2) (except for the structure contained in the indole bond formed by polymerization of a monomer) and the nitrogen-containing heterocyclic ring At least one structure of the group (Z); (In the formula (2-1), R ¹ is a halogen atom, an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms; r1 is an integer of 0 to 2, and r2 is 0 to 3; An integer; wherein, r1+r2≦4 is satisfied; “*1” represents a bond; in the formula (2-2), R ² is a hydrogen atom or an alkyl group having a carbon number of 1 to 6; “*2” represents a bond. ). The method for producing a liquid crystal alignment film according to claim 6, wherein in the polymer having the structure (Z), all the repeating units having the structure (Z) are repeated with respect to the polymer The content of the unit is from 2 mol% to 40 mol%. The method for producing a liquid crystal alignment film according to claim 6, wherein at least one of the (A) polymer and the (B) polymer has at least one of a fluorine atom and a germanium atom. In the atom, the (A) polymer and the (B) polymer, the polymer having a low content of the specific atom has the structure (Z). The method for producing a liquid crystal alignment film according to claim 6, wherein the (B) polymer has the structure (Z). The method for producing a liquid crystal alignment film according to claim 6, wherein the (A) polymer has the structure (Y), at least one specific atom with a fluorine atom and a ruthenium atom, The (B) polymer has the structure (Z), and the content of the specific atom is lower than that of the (A) polymer. The method for producing a liquid crystal alignment film according to the above aspect, wherein the (B) polymer is a polymer obtained by reacting a tetracarboxylic dianhydride with a diamine, the tetracarboxylic acid. The acid dianhydride comprises a compound selected from the group consisting of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic acid-2:4,6:8- Dihydride, 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-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1] , 2-c]furan-1,3-dione, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, and cyclohexanetetracarboxylic dianhydride At least one of the group formed. The method for producing a liquid crystal alignment film according to the above aspect, wherein the (A) polymer has a structure represented by the following formula (3) in a main chain; (In equation (3), k and i are each independently 0 or 1, l is an integer from 2 to 9, and j is an integer from 1 to 4; "*" indicates a binding bond). A photo aligning agent comprising: (A) a polymer and (B) a polymer as at least one polymer selected from the group consisting of polyglycolic acid, polyphthalate, and polyimine. a component, wherein the (A) polymer has a structure (Y) represented by the following formula (1) in the main chain (wherein, in the case where X ¹ is -NH-, a guanamine formed by a polymerization reaction) a polymer other than a bond; (In the formula (1), X ¹ is a sulfur atom, an oxygen atom or -NH-; "*" represents a bond, respectively; wherein at least one of the two "*"s is bonded to the aromatic ring). A liquid crystal display element comprising a liquid crystal alignment film produced by the method for producing a liquid crystal alignment film according to any one of claims 1 to 12.