TWI813541B - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

The present invention provides a liquid crystal alignment agent and liquid crystal alignment agent for portable devices that can improve the adhesion between a sealant and a liquid crystal alignment film and suppress the occurrence of display unevenness near the frame of a liquid crystal display element even under high temperature and high humidity conditions. film and liquid crystal display components.

A liquid crystal alignment agent, characterized by containing the following components (A), (B) and an organic solvent. (A) component: a polymer (B) that forms a polymer film and has the ability to align liquid crystals through alignment treatment. Ingredients: Compounds with aliphatic skeleton and more than 3 epoxy groups.

Description

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

The present invention relates to a liquid crystal alignment agent for manufacturing liquid crystal display elements, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film.

Liquid crystal display elements are known as lightweight, thin, and low power consumption display devices. In recent years, high-definition liquid crystal display devices for smartphones and tablet terminals, which have rapidly expanded their market share, have also required amazing development in high display quality.

A liquid crystal display element is composed of a pair of transparent substrates with electrodes sandwiching a liquid crystal layer. However, an organic film made of organic materials is used as a liquid crystal alignment film to bring the liquid crystal into a desired alignment state between the substrates. That is, the liquid crystal alignment film is formed on the surface of the substrate holding the liquid crystal that contacts the liquid crystal in the liquid crystal display element, and plays the role of aligning the liquid crystal in a certain direction between the substrates. In addition, the pretilt angle of the liquid crystal can be controlled through the liquid crystal alignment film. In addition, the structure of the polyimide is mainly selected to increase the pretilt angle (see Patent Document 1) and reduce the pretilt angle (see Patent Document 2).

In addition, the liquid crystal display element of a method in which liquid crystal molecules are vertically aligned with a substrate in response to an electric field (VA method) includes a step of irradiating ultraviolet rays while applying a voltage to the liquid crystal molecules in the manufacturing process.

This VA-type liquid crystal display element adds a photopolymerizable compound to the liquid crystal composition in advance and uses a vertical alignment film such as polyimide type. By applying voltage to the liquid crystal cell and irradiating ultraviolet rays, the liquid crystal is enhanced. PSA (Polymer Sustained Alignment) type devices with high response speed are known (see Patent Document 3 and Non-Patent Document 1).

[Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 09-278724

[Patent Document 2] Japanese Patent Application Publication No. 10-123532

[Patent Document 3] Japanese Patent Application Publication No. 2003-307720

[Non-patent literature]

[Non-patent document 1] K. Hanaoka, SID 04 DIGEST, P.1200-1202

[Disclosure of Invention]

In recent years, in order to ensure the largest possible display area in portable devices such as smartphones and mobile phones, the width of the sealant used between the substrates of the liquid crystal display element is required to be narrower than ever before, which is called bezel narrowing. As the bezel of this panel becomes narrower, the sealant used when making liquid crystal display elements is applied at a position in contact with the end of the liquid crystal alignment film, or on the top of the liquid crystal alignment film. However, Since imine has no polar group or is less, no covalent bond is formed on the surface of the sealant and the liquid crystal alignment film, and there is a problem of insufficient bonding between the substrates.

As mentioned above, especially when used under high temperature and high humidity conditions, water is easily mixed between the sealant and the liquid crystal alignment film, causing uneven display problems near the frame of the liquid crystal display element. Therefore, it is an issue to improve the adhesiveness (adhesion) between the polyimide-based liquid crystal alignment film and the sealant or substrate. As mentioned above, the improvement of the adhesion between the liquid crystal alignment film and the sealant or substrate must be achieved without degrading the liquid crystal alignment or electrical properties of the liquid crystal alignment film. In addition, it is required to improve these properties.

As a result of careful examination, the inventors found that a liquid crystal alignment agent containing the following components (A), (B) and an organic solvent can achieve the above-mentioned problems, and thus completed the present invention.

(A) Component: a polymer that forms a polymer film and has the ability to align liquid crystals through alignment treatment

(B) Component: a compound with an aliphatic skeleton and three or more epoxy groups.

By using the liquid crystal alignment agent of the present invention, the above problems can be achieved without reducing the liquid crystal alignment or electrical properties. That is, by using the liquid crystal alignment agent of the present invention, it is possible to obtain a liquid crystal alignment that improves the adhesion between the sealant and the liquid crystal alignment film and suppresses the occurrence of display unevenness near the frame of the liquid crystal display element under high temperature and high humidity conditions. membrane. Therefore, the liquid crystal display element with this liquid crystal alignment film can improve the adhesion between the sealant and the liquid crystal alignment film, can solve the uneven display near the frame, and is suitable for use in large-screen and high-definition liquid crystal displays, especially for portable machines. .

[Form of carrying out the invention] <(A)Component>

The structure of the polymer of component (A) contained in the liquid crystal alignment agent of the present invention is not particularly limited as long as it forms a polymer film and has the ability to align liquid crystals through alignment treatment. Examples include polyamide acid and polyamide ester (hereinafter the two are also collectively referred to as polyimide precursors), polyimide and polyurea, which are imides of the aforementioned polyimide precursors. Polysiloxane, polyamide, polyamide imide, (meth)acrylate, etc. Among them, preferred are polyimide precursors and/or polyimide compounds of polyimide precursors.

The polyimide precursor of the polymer suitable for use in the liquid crystal alignment agent of the present invention has a structural unit represented by the following formula (1).

In formula (1), X ₁ is a tetravalent organic group, and Y ₁ is a divalent organic group. R ₁ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and A ₁ and A ₂ are each independently a hydrogen atom, or an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms which may have a substituent. , or an alkynyl group with 2 to 10 carbon atoms.

Specific examples of the alkyl group in R ₁ include methyl, ethyl, propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, and n-pentyl Key et al. From the viewpoint of easy imidization by heating, R ₁ is preferably a hydrogen atom or a methyl group.

In formula (1), X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and its structure is not particularly limited. In the polyimide precursor, two or more types of X ₁ may be mixed. Specific examples of X ₁ include structures of the following formulas (X-1) to (X-44).

R ₈ to R ₁₁ in the above formula (X-1) are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group, or a phenyl group. When R ₈ ~ R ₁₁ have a large volume structure, the liquid crystal alignment may be reduced, so a hydrogen atom, a methyl group, or an ethyl group is more preferred, and a hydrogen atom or a methyl group is particularly preferred.

In formula (1), X ₁ preferably contains a structure selected from (X-1) to (X-14) from the viewpoint of monomer availability.

The reliability of the obtained liquid crystal alignment film can be further improved, so the structure of _X1 is preferably an alicyclic structure such as (X-1)~(X-7) and (X-10), represented by (X-1) Better structure. In addition, in order to show good liquid crystal alignment, the structure of X ₁ is more preferably the following formula (X1-1) or (X1-2).

The preferred ratio of the structures selected from the above-mentioned (X- ₁ ) to (X-44) is 20 mol% or more of the total number of .

In formula (1), A ₁ and A ₂ are each independently a hydrogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkenyl group having 2 to 10 carbon atoms which may have a substituent, or an alkenyl group having 2 to 10 carbon atoms which may have a substituent. An alkynyl group with 2 to 10 carbon atoms.

Specific examples of the alkyl group include methyl, ethyl, propyl, butyl, t-butyl, hexyl, octyl, decyl, cyclopentyl, cyclohexyl, bicyclohexyl, and the like. Examples of the alkenyl group include those in which one or more CH-CH structures present in the above-mentioned alkyl group are substituted with a C=C structure. More specifically, examples include vinyl, allyl, 1-propenyl, and isopropenyl. , 2-butenyl, 1,3-butadienyl, 2-pentenyl, 2-hexenyl, cyclopropenyl, cyclopentenyl, cyclohexenyl, etc. Examples of the alkynyl group include those in which one or more CH ₂ -CH ₂ structures present in the alkyl group are substituted with a C≡C structure. More specifically, examples include ethynyl, 1-propynyl, and 2-propyne. Key et al.

The above-mentioned alkyl group, alkenyl group, and alkynyl group may have a substituent, and may further form a ring structure through the substituent. In addition, the formation of a ring structure by substituents means that the substituents are bonded to each other or to a part of the parent skeleton to form a ring structure.

Examples of such substituents include halogen group, hydroxyl group, mercapto group, nitro group, aryl group, organoxy group, organothio group, organosilyl group, hydroxyl group, ester group, sulfur group Ester group, phosphate ester group, amide group, alkyl group, alkenyl group, alkynyl group, etc.

Examples of the halogen group of the substituent include a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

Examples of the aryl group of the substituent include phenyl group. This aryl group may also be substituted by other substituents mentioned above.

The organic oxygen group of the substituent may represent a structure represented by -O-R. This R may be the same or different, and examples thereof include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These R may be further substituted by the aforementioned substituents. Specific examples of the organic oxygen group include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, and the like.

The organic sulfide group of the substituent may represent a structure represented by -S-R. Examples of R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These R may be further substituted by the aforementioned substituents. Specific examples of the organic sulfide group include methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, hexylthio group, heptylthio group, octylthio group, and the like.

The organosilyl group of the substituent may represent a structure represented by -S1-(R) ₃ . This R may be the same or different, and examples thereof include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These R may be further substituted by the aforementioned substituents. Specific examples of the organosilyl group include trimethylsilyl, triethylsilyl, tripropylsilyl, tributylsilyl, tripentylsilyl, trihexylsilyl, and pentylsilyl. Dimethylsilyl, hexyldimethylsilyl, etc.

The acyl group of the substituent may represent a structure represented by -C(O)-R. Examples of R include the aforementioned alkyl group, alkenyl group, aryl group, and the like. These R may be further substituted by the aforementioned substituents. Specific examples of the acyl group include a formyl group, an acetyl group, a propionyl group, a butylyl group, an isobutylyl group, a pentyl group, an isopentyl group, a benzoyl group, and the like.

The ester group of the substituent may represent a structure represented by -C(O)O-R or -OC(O)-R. Examples of R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These R may be further substituted by the aforementioned substituents.

The thioester group of the substituent may represent a structure represented by -C(S)O-R or -OC(S)-R. Examples of R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These R may be further substituted by the aforementioned substituents.

The phosphate group of the substituent may represent a structure represented by -OP(O)-(OR) ₂ . This R may be the same or different, and examples thereof include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These R may be further substituted by the aforementioned substituents.

The amide group of the substituent can be represented by -C(O)NH ₂ , or -C(O)NHR, -NHC(O)R, -C(O)N(R) ₂ , or -NRC(O)R. structure. This R may be the same or different, and examples thereof include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These R may be further substituted by the aforementioned substituents.

Examples of the aryl group of the substituent include the same aryl groups as described above. This aryl group may be further substituted by other substituents as described above.

Examples of the alkyl group of the substituent include the same alkyl groups as described above. This alkyl group may be further substituted by other substituents mentioned above.

Examples of the alkenyl group of the substituent include the same alkenyl groups as described above. This alkenyl group may be further substituted by other substituents as described above.

Examples of the alkynyl group of the substituent include the same alkynyl groups as described above. This alkynyl group may be further substituted by other substituents mentioned above.

Generally, if a bulky structure is introduced, the reactivity or liquid crystal alignment of the amine group may be reduced. Therefore, A ₁ and A ₂ are preferably hydrogen atoms or alkyl groups with 1 to 5 carbon atoms that may have substituents. , particularly preferably a hydrogen atom, a methyl group or an ethyl group.

In formula (1), Y ₁ is a divalent organic group derived from diamine, and its structure is not particularly limited. The diamine is represented by the following formula. Specific examples of the structure of Y ₁ include the following Y-1 to Y-194.

式中n為1~6之整數。

In the formula, n is an integer from 1 to 6.

Boc in the above formula represents the third butoxycarbonyl group.

(In formula (Y-192), m and n are independently integers from 1 to 11, m+n is an integer from 2 to 12, in formulas (Y-193) and (Y-194), j is 0~3 an integer).

_Y1 is more preferably at least one selected from the structures represented by the following formulas (5) and (6) from the viewpoint of liquid crystal alignment or pretilt angle of the obtained liquid crystal alignment film.

In the formula (5), R ₁₂ is a single bond or a divalent organic group having 1 to 30 carbon atoms, R ₁₃ is a hydrogen atom, a halogen atom or a monovalent organic group having 1 to 30 carbon atoms, and a is a group of 1 to 4 carbon atoms. When a is an integer and is 2 or more, R ₁₂ and R ₁₃ may be the same as or different from each other.

In formula (6), R ₁₄ is a single bond, -O-, -S-, -NR ₁₅ -, amide bond, ester bond, urea bond, or a divalent organic group having 1 to 40 carbon atoms, and R ₁₅ is Hydrogen atom or methyl group.

Specific examples of formula (5) and formula (6) include the following structures.

The structure with high linearity can improve the alignment of liquid crystal when used as a liquid crystal alignment film. Therefore, Y ₁ is preferably Y-7, Y-21, Y-22, Y-23, Y-25, Y-43, Y-44, Y-45, Y-46, Y-48, Y-54, Y-62, Y-63, Y-64, Y-65, Y-66, Y-67, or Y-160. The proportion of the above structure that can improve the alignment of liquid crystal is preferably 20 mol% or more of the total _Y1 , more preferably 60 mol% or more, and still more preferably 80 mol% or more.

When used as a liquid crystal alignment film, when the pretilt angle of the liquid crystal is to be increased, Y ₁ is preferably a structure with a long-chain alkyl group, an aromatic ring, an aliphatic ring, a steroid skeleton, or a combination of these on the side chain. . This Y ₁ is preferably Y-170~Y-191.

Moreover, in formula (5), it is preferable that the side chain part has a structure substituted by the following formula [III-1] or [III-2].

In the above (III-1), X ¹ represents a single bond, -(CH ₂ ) _a - (a is an integer from 1 to 15), -O-, -CH ₂ O-, -COO- or -OCO-. X ² represents a single bond or (CH ₂ ) _b - (b is an integer from 1 to 15). X ³ represents a single bond, -(CH ₂ ) _c - (c is an integer from 1 to 15), -O-, -CH ₂ O-, -COO- or -OCO-. X ⁴ represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocyclic ring. Any hydrogen atom in these cyclic groups can be an alkyl group with a carbon number of 1 to 3, or an alkyl group with a carbon number of 1 An alkoxy group of ~3, a fluorine-containing alkyl group with 1 to 3 carbon atoms, a fluorine-containing alkoxy group with 1 to 3 carbon atoms or a fluorine atom is substituted. In addition, X ⁴ can also be selected from the group consisting of 17 carbon atoms with a steroid skeleton. ~51 organic radical is a 2-valent organic radical. X ⁵ represents a divalent cyclic group selected from benzene ring, cyclohexane ring and heterocyclic ring. Any hydrogen atom on these cyclic groups can be passed through an alkyl group with 1 to 3 carbon atoms, or an alkyl group with 1 carbon atoms. It is substituted by an alkoxy group with ~3 carbon atoms, a fluorine-containing alkyl group with 1 ~ 3 carbon atoms, a fluorine-containing alkoxy group with 1 ~ 3 carbon atoms, or a fluorine atom. n represents an integer from 0 to 4. X ⁶ represents an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, or a fluorine-containing alkoxy group having 1 to 18 carbon atoms.

Among them, X ¹ is preferably a single bond, -(CH ₂ ) _a - (a is an integer from 1 to 15), -O-, -CH ₂ O- or -COO from the viewpoint of the ease of obtaining raw materials or synthesis. -, more preferably a single bond, -(CH ₂ ) _a - (a is an integer from 1 to 10), -O-, -CH ₂ O- or -COO-. Among them, X ² is preferably a single bond or (CH ₂ ) _b - (b is an integer from 1 to 10). From the viewpoint of ease of synthesis, X ³ is preferably a single bond, -(CH ₂ ) _c - (c is an integer from 1 to 15), -O-, -CH ₂ O- or -COO-, and more preferably Single bond, -(CH ₂ ) _c - (c is an integer from 1 to 10), -O-, -CH ₂ O- or -COO-.

Among them, X ⁴ is preferably a benzene ring, a cyclohexane ring or an organic group having 17 to 51 carbon atoms having a steroid skeleton, from the viewpoint of ease of synthesis. X ⁵ is preferably a benzene ring or a cyclohexane ring. From the viewpoint of the ease of obtaining or synthesizing raw materials, n is preferably 0 to 3, more preferably 0 to 2.

X ⁶ is preferably an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, or a fluorine-containing alkoxy group having 1 to 10 carbon atoms. More preferably, it is an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. Particularly preferred is an alkyl group having 1 to 9 carbon atoms or an alkoxy group having 1 to 9 carbon atoms.

Preferable combinations of ^X1 , ^X2 , ^X3 , ^X4 , ^{X5 ,} The same combinations as (2-1)~(2-629) disclosed in Tables 6~47 on pages 34 to 34. In addition, in the tables of the above-mentioned International Publication, X ¹ to X ⁶ in the present invention are represented by Y1 to Y6, but Y1 to Y6 can also be interpreted as X ¹ to X ⁶ .

Furthermore, among the tables (2-605) to (2-629) disclosed in the above-mentioned International Publication Gazette, the organic group having a carbon number of 17 to 51 having a steroid skeleton in the present invention is an organic group having a steroid skeleton having a carbon number of 12 It represents an organic group with a carbon number of ~25, but an organic group with a carbon number of 12-25 in the steroid skeleton can be interpreted as an organic group with a carbon number of 17-51 in the steroid skeleton. Among them, (2-25)~(2-96), (2-145)~(2-168), (2-217)~(2-240), (2-268)~(2-315), The combination of (2-364)~(2-387), (2-436)~(2-483) or (2-603)~(2-615) is better. The best combinations are (2-49)~(2-96), (2-145)~(2-168), (2-217)~(2-240), (2-603)~(2-606 ), (2-607)~(2-609), (2-611), (2-612) or (2-624).

[Chemical 35] ─X ⁷ ─X ⁸ [III-2]

In the above (III-2), X ⁷ represents a single bond, -O-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, - COO- or -OCO-. X ⁸ represents an alkyl group having 8 to 22 carbon atoms or a fluorine-containing alkyl group having 6 to 18 carbon atoms. Among them, X ⁷ is preferably a single bond, -O-, -CH ₂ O-, -CONH-, -CON(CH ₃ )- or -COO-, more preferably a single bond, -O-, -CONH- or -COO-. X ⁸ is preferably an alkyl group having 8 to 18 carbon atoms.

The side chains that vertically align the liquid crystal preferably use a structure represented by formula [III-1] from the viewpoint of obtaining a high and stable vertical alignment property of the liquid crystal.

In addition, the ability of polymers with side chains that vertically align liquid crystals to vertically align liquid crystals varies depending on the structure of the side chains that vertically align liquid crystals. However, generally speaking, as the amount of side chains that vertically align liquid crystals increases, the polymers have side chains that vertically align liquid crystals. , which increases the ability of liquid crystal to vertically align, and decreases when it decreases. In addition, when it has a cyclic structure, the ability to vertically align liquid crystals tends to be higher than when it does not have a cyclic structure.

When the pretilt angle is to be increased, the proportion of the above structure is preferably 1 to 30 mol% of the total Y ₁ , and more preferably 1 to 20 mol%.

<Photoreactive side chain>

In formula (5), a structure in which the side chain portion is substituted by the following formula [VIII] or [IX] is also preferred.

The polymer contained in the liquid crystal alignment agent of the present invention may also have photoreactive side chains.

The photoreactive side chain may be possessed by a specific polymer, or may be possessed by a "polyimide precursor and/or polyimide thereof" of a polymer other than the specific polymer. .

<Diamines containing photoreactive side chains>

When it is desired to introduce a photoreactive side chain into a specific polymer and/or a polymer other than the specific polymer, a diamine having a photoreactive side chain may be used as a part of the diamine component. Examples of the diamine having a photoreactive side chain include diamines having a side chain represented by formula [VIII] or formula [IX], but are not limited thereto.

[Chemical 36] ─R ⁸ ─R ⁹ ─R ¹⁰ [Ⅷ] ─Y ₁ ─Y ₂ ─Y ₃ ─Y ₄ ─Y ₅ ─Y ₆ [Ⅸ]

The definitions of R ⁸ , R ⁹ and R ¹⁰ in formula [VIII] are as follows.

That is, R ⁸ represents a single bond, -CH ₂ -, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-, -N(CH ₃ ) -, -CON(CH ₃ )-, or -N(CH ₃ )CO-. In particular, R ⁸ is preferably a single bond, -O-, -COO-, -NHCO-, or -CONH-.

R ⁹ represents a single bond, an alkylene group with 1 to 20 carbon atoms that can be substituted by a fluorine atom, and the -CH ₂ - of the alkylene group can be optionally substituted by -CF ₂ - or -CH=CH-, followed by any other group When they are not adjacent to each other, they may also be substituted by these groups; -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent carbocyclic or heterocyclic rings.

In addition, the above-mentioned bivalent carbocyclic ring or heterocyclic ring specifically includes the following, but is not limited thereto.

It can be formed by ordinary organic synthesis techniques, but from the viewpoint of ease of synthesis, R ⁹ is preferably a single bond or an alkylene group having 1 to 12 carbon atoms.

R ¹⁰ represents a photoreactive group selected from the following formulas.

From the viewpoint of photoreactivity, R ¹⁰ is preferably a methacrylic group, an acrylic group (Acryl group) or a vinyl group.

Moreover, in the formula [IX], Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ and Y ₆ are defined as follows.

That is, Y ₁ represents -CH ₂ -, -O-, -CONH-, -NHCO-, -COO-, -OCO-, -NH-, or -CO-.

Y ₂ is an alkylene group, a divalent carbocyclic ring or a heterocyclic ring having 1 to 30 carbon atoms. One or a plurality of hydrogen atoms in the alkylene group, a divalent carbocyclic ring or a heterocyclic ring may be via a fluorine atom or an organic base substitution. Y ₂ is the case where the following groups are not adjacent, -CH ₂ - can also be substituted by these groups; -O-, -NHCO-, -CONH-, -COO-, -OCO-, -NH-, - NHCONH-, -CO-.

Y ₃ represents -CH ₂ -, -O-, -CONH-, -NHCO-, -COO-, -OCO-, -NH-, -CO-, or a single bond.

Y ₄ represents cinnamyl group. Y ₅ is a single bond, an alkylene group with 1 to 30 carbon atoms, a divalent carbocyclic ring or a heterocyclic ring. One or a plurality of hydrogen atoms in the alkylene group, a divalent carbocyclic ring or a heterocyclic ring can also be Fluorine atom or organic group substitution.

When Y ₅ is not adjacent to the following groups, -CH ₂ - can also be substituted by these groups; -O-, -NHCO-, -CONH-, -COO-, -OCO-, -NH-, -NHCONH-, -CO-.

Y ₆ represents a photopolymerizable group of an acrylic group or a methacrylic group.

Specific examples of the photoreactive side chain include the following, but are not limited thereto. In the following formula, X ^{9 and} The alkylene group.

Examples of the photoreactive side chain include a group that generates a photodimerization reaction (photodimerization) represented by the following formula and a group that generates a photopolymerization reaction.

In the above formula, Y ₁ to Y ₆ are the same as the above definitions.

The diamine having the above-mentioned photoreactive side chain can be mixed with the properties of liquid crystal alignment, pretilt angle, voltage holding characteristics, charge storage, etc. when used as a liquid crystal alignment film, and the response speed of liquid crystal when used as a liquid crystal display element. Use 1 type or 2 or more types.

In addition, the diamine having a photoreactive side chain is preferably 10 to 70 mol% of the diamine component used in the synthesis of polyamide acid, more preferably 20 to 60 mol%, and particularly preferably 30 mol%. ~50 mol%.

Examples of the diamine having a photoreactive side chain include a diamine having a moiety in the side chain that contains a radical generating structure that is decomposed by ultraviolet irradiation to generate radicals.

In the above formula (1), Ar, R ₁ , R ₂ , T ₁ , T ₂ , S and Q have the following definitions.

That is, Ar represents an aromatic hydrocarbon group selected from the group consisting of phenylene group, naphthylene group, and biphenylene group, which may be substituted by an organic group, and the hydrogen atom may be substituted by a halogen atom.

R ₁ and R ₂ are each independently an alkyl group or alkoxy group having 1 to 10 carbon atoms.

T ₁ and T ₂ are each independently a single bond or -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-, -N(CH ₃ )-, - CON(CH ₃ )-, -N(CH ₃ )CO- bonding group.

S is an alkylene group having 1 to 20 carbon atoms with a single bond or an unsubstituted or substituted fluorine atom. However, -CH ₂ - or -CF ₂ - of the alkylene group can be optionally substituted by -CH=CH-. When any of the groups listed below are not adjacent, they can be substituted by these groups; -O -, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent carbocyclic rings, divalent heterocyclic rings.

Q represents a structure selected from the following (in the structural formula, R represents a hydrogen atom or an alkyl group with 1 to 4 carbon atoms, and R ₃ represents -CH ₂ -, -NR-, -O-, or -S-) .

In the above formula (I), the Ar bonded by the carbonyl group is related to the absorption wavelength of ultraviolet light. Therefore, when the wavelength is increased, a structure with a longer conjugation length of the naphthyl group or biphenylene group is preferred. In addition, Ar may be substituted by a substituent, and the substituent is preferably an electron-donating organic group such as an alkyl group, a hydroxyl group, an alkoxy group, or an amino group.

In formula (I), when Ar has a structure such as naphthylene group or biphenylene group, the solubility becomes poor and the difficulty of synthesis becomes high. When the wavelength of ultraviolet rays is in the range of 250 nm to 380 nm, sufficient characteristics can be obtained even with a phenyl group, so the phenyl group is preferred.

Moreover, when R ₁ and R ₂ are each independently an alkyl group, alkoxy group, benzyl group, or phenethyl group having 1 to 10 carbon atoms, an alkyl group or an alkoxy group, R ₁ and R ₂ may form a ring.

In formula (I), Q is preferably an electron-donating organic group, and the above-mentioned group is preferably used.

When Q is an amine derivative, during the polymerization of polyamide acid, which is the precursor of polyimide, the carboxylic acid group and amine group produced may lead to undesirable formation of salts, etc., so it is more preferred to be hydroxyl or Alkoxy.

The diaminobenzene in formula (1) may have any structure of o-phenylenediamine, m-phenylenediamine, or p-phenylenediamine, but from the viewpoint of reactivity with acid dianhydride, it is preferably m-phenylenediamine, or p-phenylenediamine.

Specifically, from the viewpoint of ease of synthesis, high degree of versatility, characteristics, etc., the structure represented by the following formula is most preferred. Also, in the formula, n is an integer from 2 to 8.

Examples of the polyamide precursor used in the present invention include polyamide acid or polyamide ester obtained by the reaction of a diamine component and a tetracarboxylic acid dihydrate component.

<(B)Component>

The (B) component contained in the liquid crystal alignment agent of the present invention is a compound with an aliphatic skeleton and three or more epoxy groups. As long as the compound has an aliphatic skeleton and has three or more epoxy groups, other structures are not particularly limited. From the viewpoint of availability, etc., the compound represented by the following formula is preferred.

In the above formula, m is each independently an integer from 1 to 10, n is an integer from 1 to 10, preferably an integer from 1 to 5, R is an alkyl group with a carbon number of 1 to 7, preferably 2 to 6, p, q , r are each independently 1 to 8, preferably an integer of 1 to 6.

Preferred specific examples include the compounds illustrated below.

<Production of polyamide precursor-polyamide acid>

The polyamide precursor of the polyimide used in the present invention can be produced by the following method. Specifically, the diamine component and the tetracarboxylic dianhydride component can be mixed in the presence of an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, for 30 minutes to 24 hours, Preferably, it takes 1 to 12 hours to react and synthesize.

The reaction between the diamine component and the tetracarboxylic dianhydride component is usually carried out in an organic solvent. The organic solvent used at this time is not particularly limited as long as it can dissolve the produced polyimide precursor. Specific examples of organic solvents used in the reaction are listed below, but are not limited to these examples. Examples include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethylformamide. Methylthionoxide or 1,3-dimethyl-imidazolinone.

In addition, when the solubility of the polyimide precursor is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone or the following formula can be used [D-1]~Organic solvent represented by formula [D-3].

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

These solvents can be used alone or in mixture. In addition, even a solvent that does not dissolve the polyimide precursor can be mixed with the solvent within the range that the generated polyimide precursor is not precipitated. In addition, the moisture in the solvent will hinder the polymerization reaction and may further cause hydrolysis of the generated polyimide precursor. Therefore, it is better to use a solvent that has been dehydrated and dried.

The concentration of the polyamide polymer in the reaction system is preferably 1 to 30 mass %, more preferably 5 to 20 mass %, since the polymer is less likely to precipitate and can easily obtain a high molecular weight body.

The polyamic acid prepared as above can be recovered by injecting the reaction solution into a weak solvent while stirring it thoroughly, so that the polymer can be precipitated and recovered. In addition, after several times of precipitation, washing with a weak solvent, and drying at room temperature or heating, the purified polyamide powder can be obtained. The weak solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, and the like.

<Production of polyimide precursor-polyamide ester>

The polyamide ester of the polyimide precursor used in the present invention can be produced by the following manufacturing method (1), (2) or (3).

(1) When made of polyamide

Polyamic acid ester can be produced by esterifying the polyamic acid produced as described above. Specifically, the polyamic acid and the esterifying agent are processed in the presence of an organic solvent at -20~150°C, preferably 0~50°C, for 30 minutes to 24 hours, preferably 1~4 hours. react to create.

The esterifying agent is preferably one that can be easily removed by purification. Examples include N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, and N,N-dimethylformamide diethyl acetal. -Dimethylformamide dipropyl acetal, N,N-dimethylformamide dineopentylbutyl acetal, N,N-dimethylformamide di-t-butyl acetal , 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene, 4-(4 , 6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (methylmorpholinium chloride), etc. The amount of esterification agent added is 1 mole relative to the repeating unit of polyamide acid, preferably 2 to 6 mole equivalents.

Examples of organic solvents include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, and N,N-dimethylacetamide. , dimethylsulfoxide or 1,3-dimethyl-imidazolinone. In addition, when the solvent solubility of the polyimide precursor is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the above-mentioned solvents can be used. Solvents represented by formula [D-1] to formula [D-3].

These solvents can be used alone or in mixture. In addition, even if it is a solvent that does not dissolve the polyimide precursor, it can be mixed with the above-mentioned organic solvent as long as the generated polyimide precursor does not precipitate. In addition, the moisture in the solvent will hinder the polymerization reaction and cause hydrolysis of the generated polyimide precursor, so it is better to use a solvent that has been dehydrated and dried.

The solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone based on the solubility of the polymer. One or more of these can be used. Use by mixing 2 or more types. The concentration during production is preferably 1 to 30 mass %, more preferably 5 to 20 mass %, since the polymer is less likely to precipitate and a high molecular weight body can be easily obtained.

(2) Produced by the reaction of tetracarboxylic acid diester dichloride and diamine

Polyamide esters can be manufactured from tetracarboxylic acid diester dichloride and diamine.

Specifically, tetracarboxylic acid diester dichloride and diamine can be processed in the presence of alkali and organic solvent at -20~150°C, preferably 0~50°C, for 30 minutes to 24 hours. Preferably, the reaction time is 1 to 4 hours.

Examples of the base include pyridine, triethylamine, 4-dimethylaminopyridine, and the like. However, in order to ease the reaction, pyridine is preferred. The added amount of the base is preferably 2 to 4 moles relative to the tetracarboxylic acid diester dichloride from the viewpoint of easily removing the base and obtaining a high molecular weight body.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone based on the solubility of the monomer and polymer. One type of these may be used or two or more types may be mixed and used. The polymer concentration at the time of production is preferably 1 to 30 mass %, more preferably 5 to 20 mass %, from the viewpoint that the polymer is less likely to cause precipitation and a high molecular weight body can be easily obtained. In addition, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for manufacturing the polyamide ester is preferably dehydrated as much as possible, preferably in a nitrogen environment to prevent the mixing of outside air.

(3) When produced from tetracarboxylic acid diester and diamine

Polyamic acid ester can be produced by polycondensation of tetracarboxylic acid diester and diamine.

Specifically, the tetracarboxylic acid diester and the diamine can be reacted in the presence of a condensing agent, an alkali, and an organic solvent at 0°C to 150°C, preferably 0°C to 100°C, for 30 minutes to 24 hours, preferably 3 to 15 hours to produce.

As the aforementioned condensation agent, triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N' -Carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholine, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyl Urea tetrafluoroborate, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethylmethylurea hexafluorophosphate, (2,3-dihydro-2 - Diphenyl thioxo-3-benzoxazolyl)phosphonate, etc. The amount of the condensation agent added is preferably 2 to 3 times molar relative to the tetracarboxylic acid diester.

As the aforementioned base, tertiary amines such as pyridine and triethylamine can be used. The added amount of alkali is an amount that can be easily removed, and from the viewpoint of easily obtaining a high molecular weight body, 2 to 4 times molar relative to the diamine component is preferred.

In addition, in the above reaction, the reaction proceeds efficiently by adding a Lewis acid as an additive. The Lewis acid is preferably a lithium halide such as lithium chloride or lithium bromide. The amount of Lewis acid added is preferably 0 to 1.0 times molar relative to the diamine component.

Among the above three types of production methods of polyamic acid ester, in order to obtain a high molecular weight polyamic acid ester, the production method of the above (1) or the above (2) is particularly preferred.

The polyamic acid ester solution obtained as described above can be poured into a weak solvent while being thoroughly stirred, so that the polymer can be precipitated. After several precipitations and washing with a weak solvent, the purified polyamic acid ester powder can be obtained after drying at room temperature or heating. The weak solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, and the like.

<Polyimide>

The polyimide used in the present invention can be produced by imidizing the aforementioned polyamide ester or polyamide acid. When producing polyimide from polyamide ester, an alkaline catalyst is added to the polyamide ester solution or a polyamide acid solution obtained by dissolving polyamide ester resin powder in an organic solvent. The chemical imidization is relatively simple. Chemical imidization is carried out at a relatively low temperature. During the imidization process, the molecular weight of the polymer is not easily reduced, so it is preferred.

Chemical imidization can be carried out by stirring the polyamide ester to be imidized in an organic solvent in the presence of an alkaline catalyst. As the organic solvent, the solvent used in the aforementioned polymerization reaction can be used. Examples of alkaline catalysts include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like. In particular, triethylamine is preferred because it has sufficient basicity required for the reaction to proceed.

The temperature during the imidization reaction is -20°C to 140°C, preferably 0°C to 100°C, and the reaction time is 1 to 100 hours. The amount of alkaline catalyst is 0.5 to 30 molar times of the amide ester group, preferably 2 to 20 molar times. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. Since the added catalyst and the like remain in the solution after the imidization reaction, the obtained imidized polymer is recovered by the following means and redissolved in an organic solvent to form the liquid crystal of the present invention. Alignment agent is preferred.

When producing polyimide from polyamic acid, it is simple to chemically imidize the solution by adding a catalyst to a solution of the polyamic acid obtained by the reaction of a diamine component and a tetracarboxylic dianhydride. Chemical imidization is preferred because it carries out the imidization reaction at a lower temperature because the molecular weight of the polymer is not likely to decrease during the imidization process.

Chemical imidization can be carried out by stirring the polyamide to be imidized in an organic solvent in the presence of an alkaline catalyst and an acid anhydride. As the organic solvent, the solvent used in the aforementioned polymerization reaction can be used. Examples of alkaline catalysts include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like. Among them, pyridine is preferred because it has moderate basicity required for the reaction. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Among them, acetic anhydride is preferred because purification after completion of the reaction becomes easy.

The temperature during the imidization reaction is -20°C to 140°C, preferably 0°C to 100°C, and the reaction time is 1 to 100 hours. The amount of the alkaline catalyst is 0.5~30 mol times of the amide acid group, preferably 2~20 mol times, and the amount of the acid anhydride is 1~50 mol times of the amide acid group, preferably 3~ 30 molar times. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time.

Since added catalysts, etc. remain in the solution after the imidization reaction of polyamic acid ester or polyamic acid, the obtained imidized polymer is recovered by the following means. The organic solvent is redissolved and is preferably used as the liquid crystal alignment agent of the present invention.

The polyimide solution obtained as above can be stirred thoroughly and poured into a weak solvent to precipitate the polymer. Furthermore, by precipitating several times, washing with a weak solvent, and drying at room temperature or heating, purified polyamic acid ester powder can be obtained.

The weak solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and the like.

<Liquid crystal alignment agent>

The liquid crystal alignment agent of the present invention has the form of a solution in which the aforementioned component (A) and component (B) are dissolved in an organic solvent. The molecular weight of the polymer of component (A) is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, and still more preferably 10,000 to 100,000 in terms of weight average molecular weight. Moreover, the number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, still more preferably 5,000 to 50,000.

The content of the aforementioned component (A) in the liquid crystal alignment agent of the present invention can be appropriately changed by setting the thickness of the coating film to be formed. However, from the perspective of forming a uniform and defect-free coating film, it is preferably 1% by weight or more. , from the viewpoint of the storage stability of the solution, it is preferably 10% by weight or less. Among them, 2 to 8 wt% is preferred, and 3 to 7 wt% is particularly preferred.

In addition, the content of the aforementioned component (B) in the liquid crystal alignment agent of the present invention is, for reasons such as liquid crystal alignment and storage stability, relative to 100 parts by weight of the aforementioned component (A) contained in the liquid crystal alignment agent ( PHR), preferably 1 to 30 parts by weight, particularly preferably 3 to 15 parts by weight.

The organic solvent contained in the liquid crystal alignment agent of the present invention is not particularly limited as long as the aforementioned component (A) and component (B) are uniformly dissolved. Among them, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylstrioxide, γ-butyrolactone, 1,3-dimethyl-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone or 4-hydroxy-4-methyl-2-pentanone, etc. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and γ-butyrolactone are preferably used.

The content of the organic solvent contained in the liquid crystal alignment agent of the present invention is preferably 50 to 99% by weight, particularly preferably 80 to 99% by weight, from the viewpoint of storage stability or coating properties.

The liquid crystal alignment agent of the present invention can use a solvent (also called a weak solvent) that improves the coating properties or surface smoothness of the liquid crystal alignment film when coating the liquid crystal alignment agent within the scope that does not impair the effect of the present invention. Specific examples of the following weak solvents can be cited, but the solvent is not limited to these examples.

Examples include ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, and 2-methyl-1 -Butanol, isoamyl alcohol, tert-pentanol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol Alcohol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol , 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1,2-ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanol Diol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2- Ethyl-1,3-hexanediol, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2 -Butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2- Hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate Acid ester, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2-(methoxymethoxy)ethanol, ethylene glycol monobutyl ether, ethylene glycol mono Isoamyl ether, ethylene glycol monohexyl ether, 2-(hexyloxy)ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, propylene glycol monobutyl ether, 1-(butoxyethoxy)propanol, propylene glycol monomethyl Ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, Ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-( 2-Ethoxyethoxy)ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate , methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate B Ester, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate ester, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate or solvents represented by the aforementioned formulas [D-1] to formulas [D-3], etc.

Among them, 1-hexanol, cyclohexanol, 1,2-ethylene glycol, 1,2-propylene glycol, propylene glycol monobutyl ether, ethylene glycol monobutyl ether or dipropylene glycol dimethyl ether is preferably used.

These weak solvents are preferably 1 to 80% by mass of the total solvents contained in the liquid crystal alignment agent. Among them, 10 to 80% by mass is preferred. More preferably, it is 20~70% by mass.

In the liquid crystal alignment agent of the present invention, in addition to the above, as long as the effects of the present invention are not impaired, polymers other than the aforementioned component (A) can also be added to change the electrical properties such as the dielectric constant or conductivity of the liquid crystal alignment film. Dielectrics or conductive substances for the purpose, silane coupling agents for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate, cross-linking compounds for the purpose of improving the hardness or density of the film when used as a liquid crystal alignment film, And imidization accelerators for the purpose of more efficient imidization by heating the polyimide precursor during calcination of the coating film, etc.

In addition, in order to improve the mechanical strength of the liquid crystal alignment film, the following additives may be added to the liquid crystal alignment agent of the present invention.

The above-mentioned additive is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent. If it is less than 0.1 parts by mass, no effect can be expected. If it exceeds 30 parts by mass, the alignment of the liquid crystal will be reduced, so 0.5 to 20 parts by mass is more preferred.

<Liquid crystal alignment film>

The liquid crystal alignment film of the present invention is a film obtained by coating the above-mentioned liquid crystal alignment agent on a substrate, drying and calcining it. The substrate coated with the liquid crystal alignment agent of the present invention is not particularly limited as long as it is a highly transparent substrate. Glass substrates, silicon nitride substrates, acrylic substrates, polycarbonate substrates, and other plastic substrates can be used. Depending on the manufacturing process, From the viewpoint of simplicity, it is preferable to use a substrate on which ITO (Indium Tin Oxide) electrodes for liquid crystal driving are formed. In addition, in the case of a reflective liquid crystal display element, when only one side of the substrate is used, an opaque material such as a silicon wafer may be used. In this case, the electrode may also use a light-reflecting material such as aluminum.

The coating method of the liquid crystal alignment agent of the present invention includes spin coating method, printing method, inkjet method, etc. Any temperature and time can be selected for the drying and calcining steps after coating the liquid crystal alignment agent of the present invention. Usually, in order to fully remove the organic solvent contained, the material is dried at 50°C to 120°C for 1 to 10 minutes, and then calcined at 150°C to 300°C for 5 to 120 minutes. The thickness of the fired coating film is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may be reduced, so it is 5 to 300 nm, preferably 10 to 200 nm.

Methods for subjecting the obtained liquid crystal alignment film to alignment treatment include rubbing method, photo-alignment treatment method, and the like.

The friction treatment can be performed using existing friction equipment. The material of the friction cloth at this time can include cotton, nylon, rayon, etc. The conditions for friction treatment generally use the conditions of rotation speed 300~2000rpm, conveying speed 5~100mm/s, and pushing amount 0.1~1.0mm. Then, use pure water or alcohol to remove any residue caused by friction by ultrasonic cleaning.

Specific examples of the photo-alignment treatment method include irradiating the surface of the above-mentioned coating film with radiation that is biased in a certain direction, and sometimes heating it at a temperature of 150 to 250°C to impart alignment energy to the liquid crystal. As the radiation, ultraviolet rays and visible rays with a wavelength of 100 to 800 nm can be used. Among them, ultraviolet rays having a wavelength of 100 to 400 nm are preferred, and those having a wavelength of 200 to 400 nm are particularly preferred. In addition, in order to improve the liquid crystal alignment, the coated substrate can be heated at 50 to 250°C while irradiating radiation. The irradiation dose of the aforementioned radiation is preferably 1 to 10,000 mJ/cm ² , and particularly preferably 100 to 5,000 mJ/cm ² . The liquid crystal alignment film produced as above can stabilize the alignment of liquid crystal molecules in a specific direction.

The higher the extinction ratio of polarized ultraviolet rays, the higher the anisotropy can be imparted, so it is preferable. Specifically, the extinction ratio of linearly polarized ultraviolet light is preferably 10:1 or more, and more preferably 20:1 or more.

The film irradiated with polarized radiation may then be subjected to a contact treatment containing at least one solvent selected from water and organic solvents.

The solvent used for the contact treatment is not particularly limited as long as it can dissolve decomposition products generated by light irradiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, and butyl cellosolve. Agent, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate and cyclohexyl acetate, etc. Two or more types of these solvents may be used in combination.

From the viewpoint of versatility or safety, at least one selected from the group consisting of water, 2-propanol, 1-methoxy-2-propanol, and ethyl lactate is more preferred. Particularly preferred solvents are water, 2-propanol, and mixed solvents of water and 2-propanol.

In the present invention, the contact treatment between a film irradiated with polarized radiation and a solution containing an organic solvent is preferably carried out by immersion treatment, spray treatment, or the like to fully contact the film with the liquid. Among them, the method of immersing the membrane in a solution containing an organic solvent is preferably 10 seconds to 1 hour, more preferably 1 to 30 minutes. The contact treatment can be performed at normal temperature or heated, preferably at 10 to 80°C, more preferably at 20 to 50°C. In addition, when necessary, means to improve contact such as ultrasonic waves can be implemented.

After the above contact treatment, in order to remove the organic solvent in the use solution, it can also be washed (cleaned) or dried with low boiling point solvents such as water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, etc. One or both.

In addition, the film that has been contacted with a solvent can be heated above 150°C in order to dry the solvent and realign the molecular chains in the film.

The preferred heating temperature is 150~300℃. The higher the temperature, the more it can promote the realignment of molecular chains. However, when the temperature is too high, there is a concern that it will be accompanied by the decomposition of molecular chains. Therefore, the preferred heating temperature is 180~250℃, and the particularly preferred temperature is 200~230℃.

If the heating time is too short, the effect of realignment of the molecular chains may not be obtained. If the heating time is too long, there is a possibility of decomposition of the molecular chains. Preferably, it is 10 seconds to 30 minutes, and more preferably 1 minute to 10 minutes.

<Liquid crystal display element>

The liquid crystal display element of the present invention is provided with a liquid crystal alignment film obtained by the above-mentioned manufacturing method of a liquid crystal alignment film. The liquid crystal display element of the present invention is made by using the liquid crystal alignment agent of the present invention through the above-mentioned manufacturing method of the liquid crystal alignment film to obtain a substrate with a liquid crystal alignment film. Then, a liquid crystal cell is produced by a conventional method, and the liquid crystal cell is used to form a liquid crystal display element.

As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element with a passive matrix structure is taken as an example for description. Alternatively, a liquid crystal display element with an active matrix structure in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting an image display may be used.

First, transparent glass substrates are prepared, a common electrode is provided on one of the substrates, and a segment electrode is provided on the other substrate. These electrodes, for example, can be used as ITO electrodes and are patterned to display the desired image. Next, an insulating film is provided on each substrate to cover the common electrode and the segment electrode. The insulating film may be, for example, a film composed of SiO ₂ -TiO ₂ formed by a sol-gel method.

Next, the liquid crystal alignment film of the present invention is formed on each substrate. Next, the alignment film surfaces of one substrate and the other substrate overlap each other so that they face each other, and the periphery is connected using a sealing material. In order to control the gap between the substrates, spacers can usually be mixed into the sealing material. In addition, it is preferable to spread spacers for substrate gap control also on the in-plane portions where the sealing material is not provided. A part of the sealing material is provided with an opening that can be filled with liquid crystal from the outside.

Next, a liquid crystal material is injected into the space surrounded by the two substrates and the sealing material through the opening provided in the sealing material. Then, the opening is sealed with adhesive. During injection, a vacuum injection method may be used, or a method utilizing capillary phenomena in the atmosphere may be used. Next, set up the polarizer. Specifically, a pair of polarizing plates are bonded to the surfaces opposite to the liquid crystal layers of the two substrates. Through the above steps, the liquid crystal display element of the present invention can be obtained.

In the present invention, a resin that has a reactive group such as an epoxy group, an acrylic group, a methacrylic group, a hydroxyl group, an allyl group, an acetyl group, etc. and is hardened by ultraviolet irradiation or heating can be used as the sealant. In particular, it is preferable to use a cured resin system having reactive groups of both an epoxy group and a (meth)acrylyl group.

In order to improve the adhesiveness and moisture resistance, the sealant of the present invention may be blended with an inorganic filler. The inorganic filler that can be used is not particularly limited, and specific examples include spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon carbide, silicon nitride, boron nitride, Calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, aluminum oxide, magnesium oxide, zirconium oxide, aluminum hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, titanate Barium, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., preferably spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon nitride, boron nitride, calcium carbonate, Barium sulfate, calcium sulfate, mica, talc, clay, aluminum oxide, aluminum hydroxide, calcium silicate, aluminum silicate. The above-mentioned inorganic fillers may be mixed and used in two or more types.

When manufacturing a PSA liquid crystal display composition, the liquid crystal display element can be manufactured in the following procedure.

A liquid crystal alignment film is formed by applying a liquid crystal alignment agent on two substrates and calcining it. The two substrates are arranged so that the liquid crystal alignment films face each other, and a liquid crystal layer composed of liquid crystal is sandwiched between the two substrates. That is, A liquid crystal layer is placed in contact with the liquid crystal alignment film, and a voltage is applied to the liquid crystal alignment film and the liquid crystal layer while ultraviolet rays are irradiated to cause the polymerizable compound in the liquid crystal layer to photopolymerize, and a PSA-type liquid crystal exhibiting the desired tilt angle can be produced. Display components.

When manufacturing such a PSA type liquid crystal display element, when the liquid crystal alignment agent having a photoreactive side chain structure described in this specification is used, the alignment of the liquid crystal is fixed more efficiently, resulting in a significantly excellent response speed. LCD components.

The substrate used in the PSA liquid crystal display element is a structure in which a line/slit electrode pattern of 1 to 10 μm is formed on one side of the substrate, and no slit pattern or special pattern is formed on the opposite substrate. It can also be operated, and the liquid crystal display element with this structure can simplify the manufacturing process and obtain high transmittance.

The liquid crystal material constituting the vertical alignment liquid crystal layer is not particularly limited. For example, MLC-6608 or MLC-6609 manufactured by Merck Corporation, which is mainly a negative-type liquid crystal, can be used. In addition, the PSA method can use, for example, a liquid crystal containing a polymerizable compound represented by the following formula (for example, MLC-3023 manufactured by Merck, etc.).

The steps of producing a liquid crystal cell by applying a voltage to the liquid crystal alignment film and the liquid crystal layer while irradiating ultraviolet rays include, for example, applying a voltage between electrodes provided on the substrate, applying an electric field to the liquid crystal alignment film and the liquid crystal layer, and maintaining the electric field. status, method of irradiating ultraviolet rays. Here, the voltage applied between the electrodes is, for example, 5 to 30 Vp-p, and preferably 5 to 20 Vp-p. The amount of ultraviolet irradiation is, for example, 1 to 60J, preferably 40J or less. A small amount of ultraviolet irradiation can suppress the decrease in reliability caused by damage to the components constituting the liquid crystal display element, and reduce the ultraviolet irradiation time, which can improve manufacturing efficiency. Therefore it is better.

[Example]

The following examples are given to further illustrate the present invention in detail. However, the present invention is not limited to these embodiments. The abbreviations of the following compounds and the measurement methods of each characteristic are as follows.

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

DC-1: 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride

DC-2: 1,2,3,4-cyclobutanetetracarboxylic dianhydride

DC-3: Bicyclo[3,3,0]octane-2,4,6,8-tetracarboxylic dianhydride,

DC-4: Pyromellitic anhydride,

DA-1: p-phenylenediamine,

DA-2: 1,2-bis(4-aminophenoxy)ethane

DA-3: 1,3-bis(4-aminophenoxy)propane

DA-4: 1-tert-butoxycarbonyl-1,3-bis(4-aminophenethyl)urea, DA-5: 4-(2-methylaminoethyl)aniline

DA-6: 1,3-bis(4-aminophenylethyl)urea

DA-7: 4,4’-diaminodiphenylamine

DA-8: 3,5-diaminobenzoic acid

DA-9: 3,5-diamino-N-(pyridin-3-ylmethyl)benzamide

DA-10: compound of the following formula DA-10

DA-11: compound of the following formula DA-11n

Moreover, in the following chemical formula, Boc represents t-butoxycarbonyl group.

The measurement methods for each of the following characteristics and the preparation methods for measuring samples, etc. are as follows.

<viscosity>

The viscosity of the polyamide solution, etc. is measured using an E-type viscometer TVE-22H (manufactured by Toki Industrial Co., Ltd.), with a sample volume of 1.1mL (ml), a conical rotor TE-1 (1°34', R24), and a temperature of Measurements were taken at 25°C.

<Adhesion evaluation> [Sample production]

Each liquid crystal alignment agent of the Examples and Comparative Examples described below was coated using a spin coater, and was applied to an ITO substrate of 30 mm in length × 40 mm in width. Next, after drying on a hot plate at 80°C for 2 minutes, it was calcined in a hot air circulation oven at 230°C for 30 minutes to form a coating film with a thickness of 100 nm. After irradiating the coating surface with 254nm ultraviolet light of 150mJ/cm ² through a polarizing plate, it was calcined in a hot air circulation oven at 230°C for 30 minutes to obtain a substrate with a liquid crystal alignment film.

Prepare two substrates. After applying 4 μm bead spacers on the liquid crystal alignment film surface of one of the substrates, drop the sealant (XN-1500T manufactured by Kyorytsu Chemical Co., Ltd.). Secondly, the liquid crystal alignment film surface of the other substrate is on the inside, and the overlapping width of the substrates is 1cm for lamination. At this time, adjust the dripping amount of sealant so that the diameter of the sealant after bonding becomes 3 mm. After fixing the two bonded substrates with a jig, the two substrates were thermally cured at 150° C. for 1 hour to prepare samples of Examples and Comparative Examples for adhesion evaluation.

[Measurement of Adhesion]

Each sample substrate of the above-mentioned Examples and Comparative Examples was used with a desktop precision universal testing machine AGS-X 500N manufactured by Shimadzu Corporation. After fixing the end portions of the upper and lower substrates, the upper and lower central portions of the substrates were pressed tightly, and the peeling force was measured. Force (N). The results of Examples and Comparative Examples are shown in Tables 3 and 4.

<Synthesis example 1>

In a 100mL four-necked flask with a stirring device and a nitrogen introduction tube, weigh DA-1 (0.908g) (8.40mmol), DA-2 (1.37g) (5.60mmol), DA-3 (2.17g) (8.40 mmol), and DA-4 (2.23g) (5.60mmol), 76.8g of NMP was added, and stirred to dissolve while adding nitrogen. This diamine solution was stirred and DC-1 (5.99g) (26.7mmol) was added, and 16.1g of NMP was further added, and stirred at room temperature for 24 hours to obtain a polyamide acid solution (PAA-1, viscosity: 397mPa.s ).

<Synthesis example 2>

In a 1000mL four-necked flask with a stirring device and a nitrogen introduction tube, weigh DA-1 (9.77g) (90mmol), DA-2 (21.99g) (90mmol), DA-3 (15.50g) (60mmol), and DA-4 (23.91g) (60mmol), 891.10g of NMP was added, and the mixture was stirred and dissolved while adding nitrogen. DC-1 (64.56g) (288mmol) was added while stirring the diamine solution, and 99.0g of NMP was further added, and stirred at room temperature for 24 hours to obtain a polyamide acid solution (PAA-2, viscosity: 435mPa. s).

<Synthesis example 3>

In a 500mL four-necked flask with a stirring device and a nitrogen introduction tube, weigh DA-5 (9.01g) (60.0mmol) and DA-6 (26.8g) (89.8mmol), add 290g of NMP, and add nitrogen Stir to dissolve. This diamine solution was stirred under water cooling while adding DC-2 (27.9 g) (142 mmol), and then adding 71.4 g of NMP, and stirred at 23° C. for 2 hours to obtain a polyamic acid solution (PAA-3). The viscosity of this polyamide solution at a temperature of 25°C is 750mPa. s.

<Synthesis example 4>

In a 15L four-necked flask with a stirring device and a nitrogen introduction tube, weigh DA-6 (238.7g) (800mmol) and DA-7 (637.6g) (3200mmol), add NMP 8175.5g, and add nitrogen while adding Stir to dissolve. This diamine solution was stirred under water cooling while adding DC-2 (176.5g) (900mmol), DC-3 (750.6g) (3000mmol), adding 2043.9g of NMP, and stirring at 23°C for 2 hours to obtain polyamide. Amino acid solution (PAA-4, viscosity: 1499mPa.s).

The raw material compositions of the polyimide polymers in the above synthesis examples 1 to 4 are shown in Table 1.

[Preparation of liquid crystal alignment agent]

Using the polyimide polymer obtained in the above synthesis examples 1 to 4, the liquid crystal alignment agents of Examples 1 to 6 and Comparative Examples 1 to 7 were respectively prepared as follows.

The summary of the liquid crystal alignment agents of Examples 1 to 6 and Comparative Examples 1 to 7 and the results of the adhesion evaluation are shown in Table 2, Table 3, and Table 4 described below.

(Example 1)

In a 20 ml sample tube with a stirrer placed, 3.66 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 2.79 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 3 were weighed. , add 3.00g of NMP, 0.85g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.24g of NMP solution containing AD-1 (10 mass%), and 4.57g of BCS, Stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-1).

(Example 2)

In a 20 ml sample tube with a stirrer placed, 3.66 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 2.77 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 3 were weighed. g, add 2.83g of NMP, 0.81g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.42g of NMP solution containing AD-1 (10 mass%), and 4.55g of BCS , stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-2).

(Example 3)

In a 50 ml sample tube with a stirrer placed, 4.54 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 2 and 5.40 g of the polyamic acid solution (PAA-4) obtained in Synthesis Example 4 were weighed. g, add 5.80g of NMP, 1.35g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.41g of NMP solution containing AD-1 (10 mass%), and 7.50g of BCS , stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-3).

(Example 4)

In a 50 ml sample tube with a stirrer placed, 4.54 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 2 and 5.40 g of the polyamic acid solution (PAA-4) obtained in Synthesis Example 4 were weighed. g, add 5.54g of NMP, 1.35g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.68g of NMP solution containing AD-1 (10 mass%), and 7.50g of BCS , stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-4).

(Example 5)

Weigh 3.68 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 2.78 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 3 into a 20 ml sample tube with a stirrer installed. , add 2.95g of NMP, 0.87g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.24g of NMP solution containing AD-3 (10 mass%), and 4.52g of BCS, Stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-5).

(Example 6)

In a 20 ml sample tube with a stirrer placed, 3.68 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 2.80 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 3 were weighed. g, add 2.84g of NMP, 0.81g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.41g of NMP solution containing AD-3 (10 mass%), and 4.48g of BCS , stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-6).

(Comparative example 1)

In a 20 ml sample with a stirrer placed, 3.69 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 2.78 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 3 were weighed. , add 3.22g of NMP, 0.81g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, and 4.50g of BCS, and stir for 2 hours with a magnetic stirrer to obtain a liquid crystal alignment agent (B- 1).

(Comparative example 2)

In a 20 ml sample with a stirrer placed, 3.67 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 2.79 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 3 were weighed. , add 2.99g of NMP, 0.83g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.23g of NMP solution containing AD-2 (10 mass%), and 4.49g of BCS, Stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (B-2).

(Comparative example 3)

In a 20 ml sample with a stirrer placed, 3.66 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 2.79 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 3 were weighed. , add 2.86g of NMP, 0.80g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.40g of NMP solution containing AD-2 (10 mass%), and 4.53g of BCS, Stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (B-3).

(Comparative example 4)

In a 20 ml sample with a stirrer placed, 3.68 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 2.78 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 3 were weighed. , add 2.98g of NMP, 0.84g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.26g of NMP solution containing AD-4 (10 mass%), and 4.49g of BCS, Stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (B-4).

(Comparative example 5)

In a 20 ml sample with a stirrer placed, 3.69 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 2.79 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 3 were weighed. , add 2.82g of NMP, 0.81g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.42g of NMP solution containing AD-4 (10 mass%), and 4.48g of BCS, Stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (B-5).

(Comparative example 6)

In a 50 ml sample with a stirrer placed, 4.54 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 2 and 5.40 g of the polyamic acid solution (PAA-4) obtained in Synthesis Example 4 were weighed. , add 5.80g of NMP, 1.35g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.405g of NMP solution containing AD-4 (10 mass%), and BCS (7.50g ), stir with a magnetic stirrer for 2 hours, and obtain a liquid crystal alignment agent (B-6).

(Comparative Example 7)

In a 50 ml sample with a stirrer placed, 4.54 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 2 and 5.40 g of the polyamic acid solution (PAA-4) obtained in Synthesis Example 4 were weighed. , add 5.54g of NMP, 1.35g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, 0.675g of NMP solution containing AD-4 (10 mass%), and 7.50g of BCS, Stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (B-7).

<Synthesis example 5>

Dissolve DC-3 (5.00g, 20mmol), DA-8 (3.04g, 20mmol), DA-10 (6.95g, 16mmol), and DA-11 (1.32g, 4mmol) in NMP (65.3g). After reacting at 60°C for 3 hours, DC-2 (3.77g, 19.2mmol) and NMP (15.1g) were added, and the reaction was carried out at 40°C for 4 hours to obtain a polyamic acid solution.

NMP was added to this polyamide solution (20g), and after diluting to 6.5% by mass, acetic anhydride (4.03g) and pyridine (1.25g) were added as imidization catalysts, and the reaction was carried out at 80°C for 3 hours. . The reaction solution was added to methanol (234 g), and the resulting precipitate was filtered. The precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain polyimide powder A. This polyimide has an imidization rate of 74%, a number average molecular weight of 16,000, and a weight average molecular weight of 48,000.

NMP (18.0 g) was added to the obtained polyimide powder A (2.0 g), and the mixture was stirred at 70° C. for 12 hours to dissolve. BCS (13.3g) was added to this solution, and SPI-1 was obtained by stirring at room temperature for 2 hours.

<Synthesis example 6>

DC-3 (5.00g, 20mmol), DA-9 (7.75g, 32mmol), and DA-10 (4.48g, 8mmol) were dissolved in NMP (64.9g), and allowed to react at 60°C for 3 hours, and then added DC-2 (2.31g, 11.8mmol) and NMP (9.3g) were reacted at 23°C for 1 hour, and then DC-4 (1.74g, 8mmol) and NMP (7.0g) were added and reacted at 23°C. After 6 hours, a polyamic acid solution was obtained.

NMP was added to this polyamide solution (20g) and diluted to 6.5% by mass. Acetic anhydride (4.02g) and pyridine (1.25g) were added as an imidization catalyst, and the reaction was carried out at 80°C 3 hours. The reaction solution was added to methanol (234 g), and the resulting precipitate was filtered. The precipitate was washed with methanol and dried under reduced pressure at 100° C. to obtain polyimide powder B. The polyimide has an imidization rate of 74%, a number average molecular weight of 16,000, and a weight average molecular weight of 48,000.

NMP (18.0 g) was added to the obtained polyimide powder B (2.0 g), and the mixture was stirred at 70° C. for 12 hours to dissolve. BCS (13.3g) was added to this solution, and SPI-2 was obtained by stirring at room temperature for 2 hours.

The summary of the polyimide-based polymer of the present invention is shown in Table 5.

(Example 7)

Into a 20 ml sample tube equipped with a stirrer, 5.00 g of the polyimide solution (SPI-1) obtained in Synthesis Example 5 and 5.00 g of the polyimide solution (SPI-2) obtained in Synthesis Example 6 were added. , AD-3 (0.06g), and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-7).

(Comparative example 8)

Into a 20 ml sample tube equipped with a stirrer, 5.00 g of the polyimide solution (SPI-1) obtained in Synthesis Example 5 and 5.00 g of the polyimide solution (SPI-2) obtained in Synthesis Example 6 were added. , stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (B-8).

(Comparative Example 9)

Into a 20 ml sample tube equipped with a stirrer, 5.00 g of the polyimide solution (SPI-1) obtained in Synthesis Example 5 and 5.00 g of the polyimide solution (SPI-2) obtained in Synthesis Example 6 were added. , AD-4 (0.06g), and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (B-9).

The summary of the liquid crystal alignment agents of Example 7 and Comparative Examples 8 and 9 is shown in Table 7 below. The results of the adhesiveness evaluation of each liquid crystal alignment agent of Example 7 and Comparative Examples 8 and 9 are as follows. As shown in Table 7.

In addition, the procedures for the adhesion evaluation were as described above, except that the drying on the hot plate after applying each liquid crystal alignment agent was 80°C instead of 70°C during the sample preparation for the adhesion evaluation.

[Industrial availability]

By using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film with excellent liquid crystal alignment and higher sealing adhesion can be obtained, so it can be applied to various liquid crystal display elements that require high display quality, especially for portable devices.

In addition, the entire contents of the specification, scope of patent claims, drawings, and abstract of Japanese Patent Application No. 2016-118282 filed on June 14, 2016 are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims (11)

A liquid crystal alignment agent, characterized by containing the following (A) component, (B) component and an organic solvent. The aforementioned (A) component is selected from polyimide precursors having a structural unit represented by the following formula (1) and a polymer of at least one type of polyimide which is an imide of the polyimide precursor,

(In formula (1), X ₁ is a tetravalent organic group, Y ₁ is a divalent organic group, R ₁ is a hydrogen atom or an alkyl group with 1 to 5 carbon atoms, and A ₁ and A ₂ are each independently a hydrogen atom. , or an optionally substituted alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms) wherein the component (B) is at least 1 selected from the following formula A compound with an aliphatic skeleton and more than three epoxy groups,

(In the formula, m is independently an integer from 1 to 10, n is an integer from 1 to 10, R is an alkyl group with 1 to 7 carbon atoms, and p, q, and r are each independently an integer from 1 to 8). Such as the liquid crystal alignment agent of claim 1, wherein X ₁ in formula (1) is at least one selected from the group of structures represented by the following formulas (X-1) ~ (X-14),

(In the formula, R ₈ , R ₉ , R ₁₀ and R ₁₁ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group, or a phenyl group). The liquid crystal alignment agent of claim 1 or 2, wherein X ₁ is at least one type selected from the group of structures represented by the following formulas (X1-1) and (X1-2),

The liquid crystal alignment agent of claim 1 or 2, wherein in the formula (1), Y ₁ is at least one selected from the group of structures represented by the following formulas (2) and (3),

(In formula (2), R ₁₂ is a single bond or a divalent organic group with 1 to 30 carbon atoms, R ₁₃ is a hydrogen atom, a halogen atom, or a monovalent organic group with 1 to 30 carbon atoms, and a is 1 to 4 is an integer, and when a is 2 or more, R ₁₂ and R ₁₃ may be the same or different from each other. R ₁₄ in formula (3) is a single bond, -O-, -S-, -NR ₁₅ -, or amide Bond, ester bond, urea bond, or divalent organic group with 1 to 40 carbon atoms, R ₁₅ is a hydrogen atom, or methyl group). The liquid crystal alignment agent of claim 1, wherein the aforementioned component (B) is at least one compound selected from the following formula:

The liquid crystal alignment agent of claim 1, wherein the aforementioned component (B) is at least one compound selected from the following structures:

The liquid crystal alignment agent according to any one of claims 1 to 2 and 5 to 6, wherein the aforementioned organic solvent is selected from N,N-dimethylformamide, N,N-dimethylacetamide, N- Methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyltrisoxide, γ-butyrolactone, 1,3-dimethyl-imidazolinone, methyl ethyl ketone, cyclohexan At least one kind from the group consisting of ketone, cyclopentanone, and 4-hydroxy-4-methyl-2-pentanone. The liquid crystal alignment agent according to any one of claims 1 to 2 and 5 to 6, wherein the aforementioned organic solvent further includes a liquid crystal alignment agent selected from the group consisting of 1-hexanol, cyclohexanol, 1,2-ethylene glycol, 1,2-propanediol, A weak solvent of at least one type selected from the group consisting of propylene glycol monobutyl ether, ethylene glycol monobutyl ether, and dipropylene glycol dimethyl ether. The liquid crystal alignment agent according to any one of claims 1 to 2 and 5 to 6, wherein the aforementioned component (A) contains 2 to 8% by weight, and the aforementioned component (B) is relative to the amount of resin solid content contained in the liquid crystal alignment agent. , containing 1~30% by weight, and the aforementioned organic solvent contains 50~99% by weight. A liquid crystal alignment film obtained from the liquid crystal alignment agent in any one of claims 1 to 9. A liquid crystal display element provided with the liquid crystal alignment film of claim 10.