WO2018062353A1

WO2018062353A1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display device

Info

Publication number: WO2018062353A1
Application number: PCT/JP2017/035120
Authority: WO
Inventors: 淳彦萬代; 泰宏宮本; 石川　和典; 柱永李
Original assignee: 日産化学工業株式会社
Priority date: 2016-09-29
Filing date: 2017-09-28
Publication date: 2018-04-05
Also published as: KR20190060803A; JPWO2018062353A1; TWI773689B; KR20220147158A; JP7063270B2; CN110023826A; TW201825555A; CN110023826B

Abstract

The present invention provides: a liquid crystal alignment agent which is capable of suppressing coating defects that occur in an alignment film due to the effects of a wiring structure or C/H, and suppressing a defect in which the display of a liquid crystal display device becomes non-uniform, and which has a reduced viscosity and an increased proportion of resin components; and a liquid crystal alignment film using the liquid crystal alignment agent. The present invention pertains to a liquid crystal alignment agent characterized by containing: at least one polymer selected from the group consisting of a polyimide precursor and polyimide, which is an imidized product thereof, and containing a protecting group that is removed by heat; and a solvent component containing a solvent from Group A below, a solvent from Group B below, and isobutyl ketone. The solvent from Group A is at least one solvent selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, and 1,3-dimethylimidazolidinone, and the solvent from Group B is at least one solvent selected from the group consisting of butyl cellosolve, 1-butoxy-2-propanol, 2-butoxy-1-propanol, and dipropylene glycol dimethyl ether.

Description

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

The present invention relates to a liquid crystal aligning agent that is suitable for inkjet coating and has an increased resin component ratio while maintaining a low viscosity, and a liquid crystal aligning film obtained from the liquid crystal aligning agent.

As the liquid crystal alignment film, a so-called polyimide-based liquid crystal alignment film, which is obtained by applying and baking a liquid crystal alignment agent mainly composed of a polyimide precursor such as polyamic acid (also called polyamic acid) or a soluble polyimide solution, is widely used. However, spin coating, dip coating, flexographic printing, and the like are generally known as methods for forming such a liquid crystal alignment film. Actually, there are many applications by flexographic printing.

However, flexographic printing requires various resin plates due to the different types of liquid crystal panels, the plate replacement in the manufacturing process is complicated, and film formation on a dummy substrate is required to stabilize the film formation process. There are problems such as the necessity of manufacturing the plate and the production cost of the liquid crystal display panel.

Therefore, an inkjet method has attracted attention as a new method for applying a liquid crystal alignment film without using a printing plate. The ink jet method is a method in which fine droplets are dropped on a substrate and a film is formed by wetting and spreading of the liquid. Not only the printing plate is not used, but also the printing pattern can be set freely, so that the manufacturing process of the liquid crystal display element can be simplified. In addition, there is an advantage that the waste of the coating liquid is reduced because the film formation on the dummy substrate which is necessary for flexographic printing is not necessary. The inkjet method is expected to reduce the cost of liquid crystal panels and improve production efficiency.

The liquid crystal alignment film formed by the ink jet method is required to have small film thickness unevenness inside the coating surface and high film forming accuracy in the periphery of the coating. In general, a liquid crystal alignment film formed by an ink-jet method has a trade-off relationship between the uniformity of the film thickness in the coating surface and the film forming accuracy in the periphery of the coating. Usually, a material with high in-plane uniformity has poor dimensional stability in the periphery of the coating, and the film protrudes from the set dimensions. On the other hand, the material in which the coating peripheral part is a straight line has poor uniformity in the coated surface.

In order to improve the film forming accuracy in the coating peripheral part, a method of confining the alignment film in a predetermined range with a structure has been proposed (Patent Document 1, Patent Document 2, and Patent Document 3). However, these methods have the disadvantage that additional structures are required.

Japanese Patent Publication, JP 2004-361623 A Japanese Patent Publication, JP 2008-145461 A Japanese Patent Publication, JP 2010-281925 A

In recent years, with the high definition of liquid crystal display elements, multi-layer TFT designs are becoming mainstream. In this design, a contact hole (hereinafter also referred to as C / H) is formed on the TFT substrate in order to connect the lower layer wiring and the upper layer wiring. Along with this, the spread of the liquid tends to be hindered during the application of the liquid crystal aligning agent due to the influence of the wiring structure and C / H. As a result, unevenness in the film thickness of the alignment film, such as dot-like unevenness and streaky unevenness, occurs around the C / H and other portions, and the display of the liquid crystal display element may become uneven.

In addition, the liquid crystal aligning agent used in the ink jet method is required to have low viscosity in order to stably discharge the aligning agent from the ink jet nozzle, and accordingly, the resin component ratio in the liquid crystal aligning agent is set to be small. However, on the other hand, in order to make the film thickness at the peripheral part of the alignment film uniform and suppress the width, it is preferable to increase the resin component ratio while maintaining the low viscosity. There is a need for aligning agents.

In view of the above problems, the present invention can suppress poor application of the alignment film due to the influence of the wiring structure and C / H, can suppress defects in which the display of the liquid crystal display element is non-uniform, and An object of the present invention is to provide a liquid crystal aligning agent in which the resin component ratio is increased while lowering the viscosity of the liquid crystal aligning agent, and a liquid crystal alignment film using the same.

As a result of intensive studies for solving the above problems, the present inventors have found that a liquid crystal aligning agent using a solvent having a specific structure is effective for solving the above problems, and to complete the present invention. It came.

The gist of the present invention is as described below.

1) At least one selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product thereof, and a polymer containing a protective group that is eliminated by heat;
The liquid crystal aligning agent characterized by including the solvent component containing the solvent of the following A group, the solvent of B group, and isobutyl ketone.
Group A: At least one solvent selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone and 1,3-dimethylimidazolidinone Group B: Butyl cellosolve, 1-butoxy -At least one solvent selected from the group consisting of 2-propanol, 2-butoxy-1-propanol and dipropylene glycol dimethyl ether;

According to the present invention, defective application of the alignment film caused by the influence of the wiring structure and C / H can be suppressed, the defect that the display of the liquid crystal display element is nonuniform can be suppressed, and the low viscosity. A polyimide-based liquid crystal aligning agent having a high resin component ratio and a liquid crystal aligning film using the same can be provided.

The liquid crystal aligning agent of the present invention is at least one selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product thereof, a polymer containing a protecting group that is eliminated by heat, a solvent of the above group A, And a solvent component containing isobutyl ketone and a group B solvent.

Hereafter, each component requirement will be described in detail.

<Specific solvent>
The solvent contained in the liquid crystal aligning agent of this invention contains the solvent which belongs to the said A, B, and C group.

<Group A>
The solvent belonging to Group A is at least one solvent selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, and 1,3-dimethylimidazolidinone. These solvents dissolve the polymer in the liquid crystal aligning agent.

Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and γ-butyrolactone are preferable, and N-methyl-2-pyrrolidone and γ-butyrolactone are more preferable. "

In the liquid crystal aligning agent of the present invention, the amount of the solvent belonging to Group A is preferably 20% by mass to 90% by mass and more preferably 30% by mass to 85% by mass with respect to the total mass of the liquid crystal aligning agent. More preferably, it is 50 mass% to 85 mass% or less.

<Group B>
The solvent belonging to Group B is at least one solvent selected from the group consisting of butyl cellosolve, 1-butoxy-2-propanol, 2-butoxy-1-propanol, and dipropylene glycol dimethyl ether. This solvent is a solvent that contributes to improving the application uniformity of the liquid crystal aligning agent and lowering the viscosity.

Among them, butyl cellosolve, 1-butoxy-2-propanol and dipropylene glycol dimethyl ether are preferably contained, and 1-butoxy-2-propanol is particularly preferred.

Note that commercially available 1-butoxy-2-propanol usually contains several isomers including 2-butoxy-1-propanol as isomers, and is usually used in that state.

In the liquid crystal aligning agent of the present invention, the amount of the solvent belonging to the group B is preferably 1% by mass to 50% by mass and more preferably 10% by mass to 50% by mass with respect to the total mass of the liquid crystal aligning agent. More preferably, the content is 10% by mass to 30% by mass.

The amount of the diisobutyl ketone contained in the liquid crystal aligning agent of the present invention is preferably 1% by mass to 20% by mass and more preferably 5% by mass to 20% by mass with respect to the total mass of the liquid crystal aligning agent.

<Specific polymer>
The polymer contained in the liquid crystal aligning agent of the present invention is at least one selected from the group consisting of a polyimide precursor that is a reaction product of a tetracarboxylic acid derivative component and a diamine component, and a polyimide that is an imidized product thereof, It is a polymer containing a protecting group that replaces a hydrogen atom by heat.

Hereafter, each component used as the raw material which forms a polymer is explained in full detail.

<Diamine containing a protecting group that is eliminated by heat>
The diamine component used in the liquid crystal aligning agent of the present invention includes a diamine (hereinafter, also referred to as a specific diamine) that contains a protective group that is eliminated by heat in the structure.

The structure of the protecting group is not particularly limited as long as it is a functional group that can be removed by heating. From the viewpoint of the storage stability of the liquid crystal aligning agent of the present invention, this protecting group A is preferably not desorbed at room temperature, preferably a protecting group desorbed by heat of 80 ° C. or more, more preferably 100 ° C. This is a protecting group which is eliminated by heat. Further, from the viewpoint of the efficiency of promoting thermal imidation of polyamic acid ester and the crosslinking reaction with the polyimide precursor or polyimide, it is preferably a protective group that is eliminated by heat of 300 ° C. or less, more preferably 250 ° C. The following protecting groups can be removed by heat, and more preferably, the protecting group can be removed by heat at 200 ° C. or less.

The specific diamine preferably used in the present invention contains the following structure.

In the above formula, X ¹ is an oxygen atom or a sulfur atom, A ¹ to A ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and the total number of carbon atoms is 1 to 9. * Represents a bond with another atom.

In the formula (a), X ¹ is an oxygen atom or a sulfur atom, preferably an oxygen atom. A ¹ to A ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, preferably 1 carbon atom. The total number of carbon atoms is 1 to 9, preferably 3 to 6. * Represents a bond with another atom.

Examples of the diamine having the formula (a) in the structure include diamines having the following structure. In the formula, “Boc” is a tert-butoxycarbonyl group.

The amount of the specific diamine used in the liquid crystal aligning agent of the present invention is preferably 10 mol% to 50 mol% in the total diamine component, more preferably 10 mol to 40%.

<Other diamines>
The diamine component used in the liquid crystal aligning agent of the present invention can contain other diamines as long as the effects of the present invention are exhibited in addition to the diamines described above. The structure of other diamines is not particularly limited, and can be generalized by, for example, the following formula (2).

A ₁ and A _{2 in} the above formula (2) are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms. . From the viewpoint of liquid crystal orientation, A ₁ and A ₂ are preferably a hydrogen atom or a methyl group.
An example of the structure of Y ₁ is as follows.

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

Where n is an integer from 1 to 6.

<Vertical alignment diamine: diamine having a specific side chain structure>
When the present invention is used as a VA liquid crystal aligning agent, it is preferable to prepare a polymer using a diamine having a specific side chain structure that exhibits a vertical alignment ability. The diamine having the specific side chain structure has at least one side chain structure selected from the group represented by the following formulas [S1] to [S3].

Hereinafter, the diamine having the specific side chain structure will be described in the order of the formulas [S1] to [S3].

As an example of a diamine having a specific side chain structure, there is a diamine having a specific side chain structure represented by the following formula [S1].

In the above formula [S1], X ¹ and X ² are each independently a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 15), —CONH—, —NHCO—, — CON (CH ₃ ) —, —NH—, —O—, —COO—, —OCO— or — ((CH ₂ ) _a1 —A ₁ ) _m1 — is represented. Among them, the plurality of a1 are each independently an integer of 1 to 15, the plurality of A ₁ are each independently an oxygen atom or —COO—, and m ₁ is 1 to 2.

Among these, X ¹ and X ² are each independently a single bond or — (CH ₂ ) _a — (a is an integer of 1 to 15) from the viewpoint of availability of raw materials and ease of synthesis. , —O—, —CH ₂ O— or —COO— are preferred, a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 10), —O—, —CH ₂ O— or — COO- is more preferred.

In the above formula [S1], G ¹ and G ² are each independently selected from a divalent aromatic group having 6 to 12 carbon atoms or a divalent alicyclic group having 3 to 8 carbon atoms. Represents a divalent cyclic group. Arbitrary hydrogen atoms on the cyclic group include an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, and a fluorine-containing alkoxy group having 1 to 3 carbon atoms. Alternatively, it may be substituted with a fluorine atom. m and n are each independently an integer of 0 to 3, and the sum of m and n is 1 to 4.

In the above formula [S1], R ¹ represents alkyl having 1 to 20 carbons, alkoxy having 1 to 20 carbons or alkoxyalkyl having 2 to 20 carbons. Any hydrogen that forms R ¹ may be substituted with fluorine. Among these, examples of the divalent aromatic group having 6 to 12 carbon atoms include phenylene, biphenylene, naphthalene and the like. Examples of the divalent alicyclic group having 3 to 8 carbon atoms include cyclopropylene and cyclohexylene.

Therefore, preferred specific examples of the above formula [S1] include, but are not limited to, the following formulas [S1-x1] to [S1-x7].

In the above formulas [S1-x1] to [S1-x7], R ¹ is the same as in the above formula [S1]. X ^p is — (CH ₂ ) _a — (a is an integer of 1 to 15), —CONH—, —NHCO—, —CON (CH ₃ ) —, —NH—, —O—, —CH ₂ O—, —COO— or —OCO— is represented. A ₁ represents an oxygen atom or —COO— * (a bond marked with “*” binds to (CH ₂ ) _a2 ). A ₂ represents an oxygen atom or * —COO— (the bond with “*” is bonded to (CH ₂ ) _a2 ). a ₁ is an integer of 0 or 1, and a ₂ is an integer of 2 to 10. Cy represents a 1,4-cyclohexylene group or a 1,4-phenylene group.

Further, as an example of a diamine having a specific side chain structure, there is a diamine having a specific side chain structure represented by the following formula [S2].

In the above formula [S2], X ³ represents a single bond, —CONH—, —NHCO—, —CON (CH ₃ ) —, —NH—, —O—, —CH ₂ O—, —COO— or —OCO—. Represents. Of these, X ³ is preferably —CONH—, —NHCO—, —O—, —CH ₂ O—, —COO— or —OCO— from the viewpoint of the liquid crystal orientation of the liquid crystal aligning agent.

In the above formula [S2], R ² represents alkyl having 1 to 20 carbons or alkoxyalkyl having 2 to 20 carbons. Any hydrogen that forms R ² may be substituted with fluorine. Among these, R ² is preferably an alkyl having 3 to 20 carbon atoms or an alkoxyalkyl having 2 to 20 carbon atoms from the viewpoint of the liquid crystal alignment property of the liquid crystal aligning agent.

Furthermore, as an example of a diamine having a specific side chain structure, there is a diamine having a specific side chain structure represented by the following formula [S3].

In the above formula [S3], X ⁴ represents —CONH—, —NHCO—, —O—, —COO— or —OCO—. R ³ represents a structure having a steroid skeleton. The steroid skeleton here has a skeleton represented by the following formula (st) in which three six-membered rings and one five-membered ring are bonded.

Examples of the above formula [S3] include, but are not limited to, the following formula [S3-x].

In the above formula [S3-x], X represents the above formula [X1] or [X2]. Col represents at least one selected from the group consisting of the above formulas [Col1] to [Col4], and G represents the above formula [G1] or [G2]. * Represents a site bonded to another group.

Examples of preferable combinations of X, Col and G in the above formula [S3-x] include the following. That is, a combination of [X1] and [Col1] and [G1], a combination of [X1] and [Col1] and [G2], a combination of [X1], [Col2] and [G1], and [X1] and [Col2] ] And [G2], [X1] and [Col3] and [G2], [X1] and [Col4] and [G2], [X1] and [Col3] and [G1] Combination of [X1] and [Col4] and [G1], combination of [X2] and [Col1] and [G2], combination of [X2] and [Col2] and [G2], [X2] and [Col2] and [G1], [X2], [Col3] and [G2], [X2], [Col4] and [G2], [X2], [Col1] and [G1], [X2] ], [Col4] and [G1] It is.

Specific examples of the above formula [S3] include a structure obtained by removing a hydroxyl group (hydroxy group) from a steroid compound described in paragraph [0024] of JP-A-4-281427, and paragraph [0030] of the same publication. A structure in which an acid chloride group is removed from the steroid compound, a structure in which an amino group is removed from the steroid compound described in paragraph [0038] of the publication, a structure in which a halogen group is removed from the steroid compound in paragraph [0042] of the publication, And the structures described in paragraphs [0018] to [0022] of JP-A-8-146421.

A typical example of a steroid skeleton is cholesterol (a combination of [Col1] and [G2] in the above formula [S3-x]), but a steroid skeleton that does not contain cholesterol can also be used. That is, examples of the diamine having a steroid skeleton include cholestanyl 3,5-diaminobenzoate, and the like, but a diamine component which does not include a diamine having a cholesterol skeleton is also possible. Moreover, what does not contain an amide in the connection position of a diamine and a side chain can also be utilized as a diamine which has a specific side chain structure. Even if such a diamine is used or a diamine component not containing a diamine having a cholesterol skeleton is used in the present embodiment, a liquid crystal alignment film or a liquid crystal display element capable of ensuring a high voltage holding ratio over a long period of time. It is possible to provide a liquid crystal aligning agent capable of obtaining

The diamine having a side chain structure represented by the above formulas [S1] to [S3] is represented by the following formula [1-S1]-[1-S3], respectively.

In the above formula [1-S1], X ¹ , X ² , G ¹ , G ² , R ¹ , m and n are the same as in the above formula [S1]. In the above formula [1-S2], X ³ and R ² are the same as in the above formula [S2]. In the above formula [1-S3], X ⁴ and R ³ are the same as in the above formula [S3].

<Vertical alignment diamine: diamine having a two-side chain characteristic side chain structure>
When used as a VA liquid crystal aligning agent, a polymer can be prepared using a two-side chain type diamine having two specific side chain structures with vertical alignment.
In this embodiment, the bilateral diamine which may be contained as a diamine component is represented, for example by following formula [1].

In the above formula [1], X represents a single bond, —O—, —C (CH ₃ ) ₂ —, —NH—, —CO—, —NHCO—, —COO—, — (CH ₂ ) _m —, It represents a divalent organic group consisting of —SO ₂ — or any combination thereof. Among these, X is preferably a single bond, —O—, —NH—, —O— (CH ₂ ) _m —O—. Examples of “any combination thereof” include —O— (CH ₂ ) _m —O—, —O—C (CH ₃ ) ₂ —, —CO— (CH ₂ ) _m —, —NH— (CH _{_{_{_{2) m -, - SO 2}}}} - (CH 2) m -, - CONH- (CH 2) m -, - CONH- (CH 2) m -NHCO -, - COO- (CH 2) m -OCO- , etc. However, it is not limited to these. m is an integer of 1 to 8.
In the above formula [1], two Y's independently represent the structure of the following formula [1-1].

In the above formula [1-1], Y ¹ and Y ³ are each independently a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 15), —O—, —CH _2. O—, —COO— or —OCO— is represented. Y ² represents a single bond or — (CH ₂ ) _b — (b is an integer of 1 to 15). However, when Y ¹ or Y ³ is a single bond or — (CH ₂ ) _a —, Y ² is a single bond. Y ¹ is —O—, —CH ₂ O—, —COO— or —OCO—, and / or Y ³ is —O—, —CH ₂ O—, —COO— or —OCO—. In certain instances, Y ² is a single bond or — (CH ₂ ) _b —.

In Formula [1-1], Y ⁴ represents a divalent group having 17 to 51 carbon atoms having at least one divalent cyclic group or steroid skeleton selected from the group consisting of a benzene ring, a cyclohexane ring and a heterocyclic ring. Represents an organic group. The optional hydrogen atom forming the cyclic group is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, or a fluorine-containing alkoxy group having 1 to 3 carbon atoms. It may be substituted with a group or a fluorine atom.

In the above formula [1-1], Y ⁵ represents at least one cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a heterocyclic ring. The optional hydrogen atom forming the cyclic group is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, or a fluorine-containing alkoxy group having 1 to 3 carbon atoms. It may be substituted with a group or a fluorine atom.

In the above formula [1-1], Y ⁶ represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, or an alkoxy group having 1 to 18 carbon atoms. And at least one selected from the group consisting of a group and a fluorine-containing alkoxy group having 1 to 18 carbon atoms. n is an integer of 0-4.

The two-side chain diamine having a side chain structure represented by the above formulas [S1] to [S3] is represented by the following formula [2-S1]-[2-S3], respectively.

In the above formula [1], Y may be in the meta position or in the ortho position from the position of X, but is preferably in the ortho position. That is, the formula [1] is preferably the following formula [1 ′].

In the above formula [1], the position of the _two amino groups (—NH ₂ ) may be any position on the benzene ring, but in the following formulas [1] -a1 to [1] -a3 The represented position is preferable, and the following formula [1] -a1 is more preferable. In the following formula, X is the same as in the above formula [1]. The following formulas [1] -a1 to [1] -a3 are for explaining the positions of the two amino groups, and the Y notation represented in the above formula [1] is omitted.

Therefore, based on the above formulas [1 ′] and [1] -a1 to [1] -a3, the above formula [1] is selected from the following formulas [1] -a1-1 to [1] -a3-2 The structure represented by the following formula [1] -a1-1 is more preferable. In the following formula, X and Y are the same as those in the formula [1].

Further, examples of the formula [1-1] include the following formulas [1-1] -1 to [1-1] -22, but are not limited thereto. Among these, as examples of the above formula [1-1], the following formulas [1-1] -1 to [1-1] -4, [1-1] -8 or [1-1] -10 are preferable. . In the following formula, * represents the bonding position with the phenyl group in the above formulas [1], [1 '] and [1] -a1 to [1] -a3.

When the diamine component contains a two-side chain diamine having a predetermined structure, a liquid crystal alignment film in which the ability to align the liquid crystal vertically is hardly lowered even when exposed to excessive heating. Moreover, when the diamine component contains the two-side chain diamine, even when some foreign matter comes into contact with the film and is damaged, the liquid crystal alignment film is difficult to reduce the ability to align the liquid crystal vertically. That is, the liquid crystal aligning agent from which the liquid crystal aligning film excellent in the said various characteristics can be provided because a diamine component contains this 2 side chain diamine.

<Other diamines: diamines having photoreactive side chains>
When the present invention is used as a PSA mode liquid crystal aligning agent of the vertical alignment system, a polymer is prepared using a diamine having a photoreactive side chain for the purpose of increasing the reactivity of the polymerizable compound contained in the liquid crystal. You can also.
The diamine component of this embodiment may contain a diamine having a photoreactive side chain as another diamine. When the diamine component contains a diamine having a photoreactive side chain, the photoreactive side chain can be introduced into the specific polymer or other polymers.

Examples of the diamine having a photoreactive side chain include, but are not limited to, those represented by the following formula [VIII] or [IX].

In the above formulas [VIII] and [IX], the position of the _two amino groups (—NH ₂ ) may be any position on the benzene ring, for example, on the benzene ring with respect to the linking group of the side chain. 2, 3 positions, 2, 4 positions, 2, 5 positions, 2, 6 positions, 3, 4 positions or 3, 5 positions. From the viewpoint of reactivity when synthesizing the polyamic acid, the 2,4 position, the 2,5 position, or the 3,5 position is preferred. Considering the ease of synthesis of the diamine, the positions 2, 4 or 3, 5 are more preferable.

In the above formula [VIII], R ⁸ is 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— is represented. In particular, R ⁸ is preferably a single bond, —O—, —COO—, —NHCO— or —CONH—.

In the above formula [VIII], R ⁹ represents a single bond or an alkylene group having 1 to 20 carbon atoms which may be substituted with a fluorine atom. Here, —CH ₂ — of the alkylene group may be optionally substituted with —CF ₂ — or —CH═CH—, and when any of the following groups is not adjacent to each other, these groups are substituted: -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, a divalent carbocyclic or heterocyclic ring. The divalent carbocycle or heterocycle can be specifically exemplified by the following formula (1a), but is not limited thereto.

In the formula [VIII], R ⁹ can be formed by a general organic synthetic method, but from the viewpoint of ease of synthesis, a single bond or an alkylene group having 1 to 12 carbon atoms is preferable.

In the above formula [VIII], R ¹⁰ represents a photoreactive group selected from the group consisting of the following formula (1b). Among these, R ¹⁰ is preferably a methacryl group, an acryl group or a vinyl group from the viewpoint of photoreactivity.

In the above formula [IX], Y ₁ represents —CH ₂ —, —O—, —CONH—, —NHCO—, —COO—, —OCO—, —NH— or —CO—. Y ₂ represents an alkylene group having 1 to 30 carbon atoms, a divalent carbocyclic ring or a heterocyclic ring. One or a plurality of hydrogen atoms in the alkylene group, divalent carbocyclic ring or heterocyclic ring herein may be substituted with a fluorine atom or an organic group. In Y ₂ , when the following groups are not adjacent to each other, —CH ₂ — may be substituted with these groups; —O—, —NHCO—, —CONH—, —COO—, —OCO—, —NH—, —NHCONH—, —CO—.

In the above formula [IX], Y ₃ represents —CH ₂ —, —O—, —CONH—, —NHCO—, —COO—, —OCO—, —NH—, —CO— or a single bond. . Y ₄ represents a cinnamoyl group. Y ₅ represents a single bond, an alkylene group having 1 to 30 carbon atoms, a divalent carbocycle or a heterocycle. One or a plurality of hydrogen atoms in the alkylene group, divalent carbocyclic ring or heterocyclic ring herein may be substituted with a fluorine atom or an organic group. In Y ₅ , when the following groups are not adjacent to each other, —CH ₂ — may be substituted with these groups; —O—, —NHCO—, —CONH—, —COO—, —OCO—, —NH—, —NHCONH—, —CO—. Y ₆ represents a photopolymerizable group such as an acryl group or a methacryl group.

Specific examples of the diamine having a photoreactive side chain represented by the above formula [VIII] or [IX] include the following formula (1c), but are not limited thereto.

In the formula (1c), X ⁹ and X ¹⁰ each independently represent a single bond, —O—, —COO—, —NHCO— or —NH—. Y represents an alkylene group having 1 to 20 carbon atoms which may be substituted with a fluorine atom.

Examples of the diamine having a photoreactive side chain include a diamine of the following formula [VII]. The diamine of the formula [VII] has a site having a radical generating structure in the side chain. In the radical generating structure, radicals are generated by decomposition by ultraviolet irradiation.

In the above formula [VII], Ar represents at least one aromatic hydrocarbon group selected from the group consisting of phenylene, naphthylene, and biphenylene, and the hydrogen atom of those rings may be substituted with a halogen atom. Since Ar to which carbonyl is bonded is involved in the absorption wavelength of ultraviolet rays, a structure having a long conjugate length such as naphthylene or biphenylene is preferable when the wavelength is increased. On the other hand, when Ar has a structure such as naphthylene or biphenylene, the solubility may deteriorate, and in this case, the difficulty of synthesis increases. Ar is most preferably a phenyl group because sufficient characteristics can be obtained even with a phenyl group if the wavelength of ultraviolet rays is in the range of 250 nm to 380 nm.

In the above Ar, the aromatic hydrocarbon group may be provided with a substituent. Examples of the substituent here are preferably an electron-donating organic group such as an alkyl group, a hydroxyl group, an alkoxy group, and an amino group.

In the formula [VII], R ₁ and R ₂ each independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group, a benzyl group, or a phenethyl group. In the case of an alkyl group or an alkoxy group, R ₁ and R ₂ may form a ring.

In the formula [VII], T ₁ and T ₂ are each independently a single bond, —O—, —COO—, —OCO—, —NHCO—, —CONH—, —NH—, —CH. _{_{2 O -, - N (CH}} 3) -, - CON (CH 3) - or an -N _(CH 3) CO- linking group.

In the formula [VII], S represents a single bond, unsubstituted or an alkylene group having 1 to 20 carbon atoms substituted with a fluorine atom. The alkylene group —CH ₂ — or —CF ₂ — in this case may be optionally substituted with —CH═CH—, and when any of the following groups is not adjacent to each other, May be substituted; —O—, —COO—, —OCO—, —NHCO—, —CONH—, —NH—, divalent carbocycle, divalent heterocycle;

In the formula [VII], Q represents a structure selected from the following formula (1d).

In the above formula (1d), R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. R ₃ represents —CH ₂ —, —NR—, —O—, or —S—.

In the formula [VII], Q is preferably an electron-donating organic group, and is preferably an alkyl group, a hydroxyl group, an alkoxy group, an amino group, or the like as described in the example of Ar. In the case where Q is an amino derivative, there is a possibility that a defect such as the formation of a salt between the carboxylic acid group and the amino group generated during polymerization of the polyamic acid, which is a polyimide precursor, may result in a hydroxyl group or an alkoxy group. Is more preferable.

In the above formula [VII], the position of the _two amino groups (—NH ₂ ) may be any of o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine, but is reactive with acid dianhydride. In this respect, m-phenylenediamine or p-phenylenediamine is preferable.

Therefore, preferable specific examples of the above formula [VII] include the following formulas from the viewpoint of ease of synthesis, high versatility, characteristics, and the like. In the following formula, n is an integer of 2 to 8.

These diamines having a photoreactive side chain represented by the above formula [VII], [VIII] or [IX] can be used singly or in combination of two or more. Depending on the liquid crystal alignment properties, pretilt angle, voltage holding characteristics, accumulated charge characteristics, etc., and the response speed of the liquid crystal when it is used as a liquid crystal display element, a single type or a mixture of two or more types may be used. It may be used, or in the case of using a mixture of two or more, the proportion thereof may be appropriately adjusted.

<Tetracarboxylic acid derivative>
The tetracarboxylic acid derivative component for producing the polymer having the structural unit of the above formula (1), which is contained in the liquid crystal aligning agent of the present invention, includes not only tetracarboxylic dianhydride but also its tetracarboxylic acid. Derivatives such as tetracarboxylic acid, tetracarboxylic acid dihalide compound, tetracarboxylic acid dialkyl ester compound or tetracarboxylic acid dialkyl ester dihalide compound can also be used.

As the tetracarboxylic dianhydride or a derivative thereof, it is more preferable to use at least one selected from a tetracarboxylic dianhydride represented by the following formula (3) and a derivative thereof.

In the formula, X ₁ is a tetravalent organic group having an alicyclic structure, and the structure is not particularly limited. Specific examples include the following formulas (X1-1) to (X1-44).

In formulas (X1-1) to (X1-4), R ₃ to R ₂₃ 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, carbon An alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, which may be the same or different. From the viewpoint of liquid crystal orientation, R ₃ to R ₂₃ are preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group. Specific examples of the structure of the formula (X1-1) include structures represented by the following formulas (X1-1-1) to (X1-1-6). (X1-1-1) is particularly preferable from the viewpoints of liquid crystal alignment and photoreaction sensitivity.

The polyimide precursor and the tetracarboxylic dianhydride which is a raw material of the polyimide described in the present invention and derivatives thereof are represented by the above formula (3) with respect to 1 mol of all tetracarboxylic dianhydrides and derivatives thereof. It is preferable to contain 60 to 100 mol% of tetracarboxylic dianhydride and derivatives thereof. Since a liquid crystal alignment film having good liquid crystal alignment properties can be obtained, it is more preferably 80 mol% to 100 mol%, and still more preferably 90 mol% to 100 mol%.

<Method for producing polyamic acid ester>
The polyamic acid ester which is one of the polyimide precursors used in the present invention can be synthesized by the following method (1), (2) or (3).

(1) When synthesizing from polyamic acid The polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from tetracarboxylic dianhydride and diamine.
Specifically, the polyamic acid and the esterifying agent are reacted 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 1 to 4 hours. Can be synthesized.

The esterifying agent is preferably one that can be easily removed by purification, and N, N-dimethylformamide dimethyl acetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide Dineopentyl butyl 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 and the like. The addition amount of the esterifying agent is preferably 2 to 6 molar equivalents per 1 mol of the polyamic acid repeating unit.

The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone in view of polymer solubility. These may be used alone or in combination of two or more. Good. The concentration at the time of synthesis is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is unlikely to occur and a high molecular weight product is easily obtained.

(2) When synthesizing by reaction of tetracarboxylic acid diester dichloride and diamine The polyamic acid ester can be synthesized from tetracarboxylic acid diester dichloride and diamine.

Specifically, tetracarboxylic acid diester dichloride and diamine in the presence of a base and an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C., for 30 minutes to 24 hours, preferably 1 to 4 hours. It can be synthesized by reacting.
For the base, pyridine, triethylamine, 4-dimethylaminopyridine, etc. are used.

Pyridine is preferred because the reaction proceeds gently. The addition amount of the base is preferably 2 to 4 times the molar amount of the tetracarboxylic acid diester dichloride from the viewpoint of easy removal and high molecular weight.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone from the solubility of the monomer and polymer, and these may be used alone or in combination. The polymer concentration at the time of synthesis is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is difficult to occur and a high molecular weight product is easily obtained. In order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for the synthesis of the polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent mixing of outside air in a nitrogen atmosphere.

(3) When synthesizing a polyamic acid ester from a tetracarboxylic acid diester and a diamine The polyamic acid ester can be synthesized by polycondensation of a tetracarboxylic acid diester and a diamine.

Specifically, tetracarboxylic acid diester and diamine in the presence of a condensing agent, a base, 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 It can synthesize | combine by making it react for time.

Examples of the condensing agent include triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N′-carbonyldiimidazole, dimethoxy-1,3,5-triazide. Nylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N , N ′, N′-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate diphenyl, and the like. The addition amount of the condensing agent is preferably 2 to 3 times the molar amount of the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the base is preferably 2 to 4 times mol with respect to the diamine component from the viewpoint of easy removal and high molecular weight.

In the above reaction, the reaction proceeds efficiently by adding Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The addition amount of the Lewis acid is preferably 0 to 1.0 times mol with respect to the diamine component.

Among the methods for synthesizing the three polyamic acid esters, since the high molecular weight polyamic acid ester is obtained, the synthesis method (1) or (2) is particularly preferable.

The polymer solution can be precipitated by injecting the polyamic acid ester solution obtained as described above into a poor solvent while stirring well. Precipitation is performed several times, and after washing with a poor solvent, a purified polyamic acid ester powder can be obtained at room temperature or by heating and drying. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene etc. are mentioned.

<Method for producing polyamic acid>
The polyamic acid which is a polyimide precursor used in the present invention can be synthesized by the following method.

Specifically, tetracarboxylic dianhydride and diamine are reacted 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 1 to 12 hours. Can be synthesized.

The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone in view of the solubility of the monomer and polymer. These may be used alone or in combination of two or more. It may be used. The concentration of the polymer is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is difficult to occur and a high molecular weight body is easily obtained.

The polyamic acid obtained as described above can be recovered by precipitating the polymer by pouring into the poor solvent while thoroughly stirring the reaction solution. Moreover, the powder of polyamic acid refine | purified by performing precipitation several times, washing | cleaning with a poor solvent, and normal temperature or heat-drying can be obtained. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene etc. are mentioned.

<Production method of polyimide>
The polyimide used in the present invention can be produced by imidizing the polyamic acid ester or polyamic acid. When a polyimide is produced from a polyamic acid ester, chemical imidization in which a basic catalyst is added to a polyamic acid solution obtained by dissolving the polyamic acid ester solution or the polyamic acid ester resin powder in an organic solvent is simple. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer does not easily decrease during the imidization process.

Chemical imidation can be performed by stirring the polyamic acid ester to be imidized in an organic solvent in the presence of a basic catalyst. As an organic solvent, the solvent used at the time of the polymerization reaction mentioned above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, triethylamine is preferred because it has sufficient basicity to allow the reaction to proceed.

The temperature during the imidation reaction is −20 ° C. to 140 ° C., preferably 0 ° C. to 100 ° C., and the reaction time can be 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 moles, preferably 2 to 20 moles, of the amic acid ester group. The imidation ratio of the resulting polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. Since the added catalyst or the like remains in the solution after the imidation reaction, the obtained imidized polymer is recovered by the means described below, redissolved in an organic solvent, and the liquid crystal alignment according to the present invention. It is preferable to use an agent.

When a polyimide is produced from a polyamic acid, chemical imidization in which a catalyst is added to the polyamic acid solution obtained by the reaction of a diamine component and tetracarboxylic dianhydride is simple. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is unlikely to decrease during the imidization process.

Chemical imidation can be performed by stirring a polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As an organic solvent, the solvent used at the time of the polymerization reaction mentioned above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, pyridine is preferable because it has an appropriate basicity for proceeding with the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride and the like. Among them, use of acetic anhydride is preferable because purification after completion of the reaction is facilitated.

The temperature during the imidation reaction is −20 ° C. to 140 ° C., preferably 0 ° C. to 100 ° C., and the reaction time can be 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times the amic acid group, and the amount of the acid anhydride is 1 to 50 mol times, preferably 3 to 30 mol times the amic acid group. Is double. The imidation ratio of the resulting polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time.

In the solution after the imidation reaction of polyamic acid ester or polyamic acid, the added catalyst and the like remain, so the obtained imidized polymer is recovered by the means described below, and redissolved in an organic solvent. Thus, the liquid crystal aligning agent of the present invention is preferable.

The polyimide solution obtained as described above can be polymerized by pouring into a poor solvent while stirring well. Precipitation is performed several times, and after washing with a poor solvent, a purified polyamic acid ester powder can be obtained at room temperature or by heating and drying.
The poor solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene.

<Liquid crystal aligning agent>
The liquid crystal aligning agent used in the present invention has a form of a solution in which a polymer having a specific structure is dissolved in an organic solvent. The molecular weight of the polyimide precursor and polyimide described in the present invention is preferably 2,000 to 500,000 in weight average molecular weight, more preferably 5,000 to 300,000, and still more preferably 10,000 to 100. , 000. The number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and still more preferably 5,000 to 50,000.

The concentration of the polymer of the liquid crystal aligning agent used in the present invention can be appropriately changed depending on the setting of the thickness of the coating film to be formed, but it is 1 weight from the viewpoint of forming a uniform and defect-free coating film. % From the viewpoint of storage stability of the solution, and preferably 10% by weight or less.

<Other solvents>
In the liquid crystal aligning agent of the present invention, as long as the effects of the present invention are not impaired, the polyimide precursor described in the present invention can be used as a solvent other than the solvents belonging to the groups A, B and C (hereinafter also referred to as other solvents). A solvent (also referred to as a good solvent) that dissolves the body and polyimide, or a solvent (also referred to as a poor solvent) that improves the coating properties and surface smoothness of the liquid crystal alignment film when a liquid crystal aligning agent is applied may be contained. .

Specific examples of other solvents are shown below, but the invention is not limited to these examples.
Examples of the good solvent include N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N, N-dimethylpropanamide (IPMA or 4-hydroxy-4 -Methyl-2-pentanone and the like.

Specific examples of the poor solvent include, for example, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl- 1-butanol, isopentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl -1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3- Methylcyclohex Nord, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 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 ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pen Non, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol dia Cetrate, propylene carbonate, ethylene carbonate, 2- (methoxymethoxy) ethanol, butyl cellosolve, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, 1- (Butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether Ether, dipropylene glycol monoethyl 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, diacetone alcohol, propylene glycol diacetate, diisopentyl ether, 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 ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, 3 -Ethyl methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate Examples thereof include esters, isoamyl lactate, ethyl carbitol, and solvents represented by the following formulas [D-1] to [D-3].

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

The liquid crystal aligning agent of the present invention includes at least one substituent selected from the group consisting of a crosslinkable compound having an epoxy group, an isocyanate group, an oxetane group or a cyclocarbonate group, a hydroxyl group, a hydroxyalkyl group and a lower alkoxyalkyl group. Or a crosslinkable compound having a polymerizable unsaturated bond. It is necessary to have two or more of these substituents and polymerizable unsaturated bonds in the crosslinkable compound.

Examples of the crosslinkable compound having an epoxy group or an isocyanate group include bisphenolacetone glycidyl ether, phenol novolac epoxy resin, cresol novolac epoxy resin, triglycidyl isocyanurate, tetraglycidylaminodiphenylene, tetraglycidyl-m-xylenediamine, tetra Glycidyl-1,3-bis (aminoethyl) cyclohexane, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, bisphenol hexafluoroacetodiglycidyl ether, 1,3-bis (1- (2,3-epoxypropoxy)- 1-trifluoromethyl-2,2,2-trifluoromethyl) benzene, 4,4-bis (2,3-epoxypropoxy) octafluorobiphenyl Triglycidyl-p-aminophenol, tetraglycidylmetaxylenediamine, 2- (4- (2,3-epoxypropoxy) phenyl) -2- (4- (1,1-bis (4- (2,3-epoxy) Propoxy) phenyl) ethyl) phenyl) propane or 1,3-bis (4- (1- (4- (2,3-epoxypropoxy) phenyl) -1- (4- (1- (4- (2,3 -Epoxypropoxy) phenyl) -1-methylethyl) phenyl) ethyl) phenoxy) -2-propanol and the like.

The crosslinkable compound having an oxetane group is a compound having at least two oxetane groups represented by the following formula [4A].

Specific examples include crosslinkable compounds represented by the formulas [4a] to [4k] published on pages 58 to 59 of International Publication No. WO2011 / 132751 (published 2011.10.27).

The crosslinkable compound having a cyclocarbonate group is a crosslinkable compound having at least two cyclocarbonate groups represented by the following formula [5A].

Specifically, crosslinkable compounds represented by the formulas [5-1] to [5-42] described on pages 76 to 82 of International Publication No. WO2012 / 014898 (published on 2012.2.2). It is done.

Examples of the crosslinkable compound having at least one substituent selected from the group consisting of a hydroxyl group and an alkoxyl group include an amino resin having a hydroxyl group or an alkoxyl group, such as a melamine resin, a urea resin, a guanamine resin, and a glycoluril. -Formaldehyde resin, succinylamide-formaldehyde resin or ethylene urea-formaldehyde resin. Specifically, a melamine derivative, a benzoguanamine derivative, or glycoluril in which a hydrogen atom of an amino group is substituted with a methylol group, an alkoxymethyl group, or both can be used. The melamine derivative or benzoguanamine derivative can exist as a dimer or a trimer. These preferably have an average of 3 to 6 methylol groups or alkoxymethyl groups per triazine ring.

Examples of the melamine derivative or benzoguanamine derivative include MX-750, which has an average of 3.7 substituted methoxymethyl groups per triazine ring, and an average of 5.8 methoxymethyl groups per triazine ring. MW-30 (manufactured by Sanwa Chemical Co., Ltd.) and Cymel 300, 301, 303, 350, 370, 771, 325, 327, 703, 712 and the like methoxymethylated melamine, Cymel 235, 236, Methoxymethylated butoxymethylated melamine such as 238, 212, 253, 254, butoxymethylated melamine such as Cymel 506, 508, carboxyl group-containing methoxymethylated isobutoxymethylated melamine such as Cymel 1141, Cymel 1123, etc. Methoxymethylated ethoxymethyl Benzomethylamine, methoxymethylated butoxymethylated benzoguanamine such as Cymel 1123-10, butoxymethylated benzoguanamine such as Cymel 1128, carboxyl group-containing methoxymethylated ethoxymethylated benzoguanamine such as Cymel 1125-80 (Mitsui Cyanamid) For example). Examples of glycoluril include butoxymethylated glycoluril such as Cymel 1170, methylolated glycoluril such as Cymel 1172, and methoxymethylolated glycoluril such as Powderlink 1174.
Examples of the benzene or phenolic compound having a hydroxyl group or an alkoxyl group include 1,3,5-tris (methoxymethyl) benzene, 1,2,4-tris (isopropoxymethyl) benzene, 1,4-bis ( sec-butoxymethyl) benzene or 2,6-dihydroxymethyl-p-tert-butylphenol.

More specifically, the crosslinkable compounds of the formulas [6-1] to [6-48] described on pages 62 to 66 of International Publication No. WO2011 / 132751 (published 2011.10.27) can be mentioned. It is done.

Examples of the crosslinkable compound having a polymerizable unsaturated bond include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and tri (meth) acryloyloxyethoxytrimethylol. Crosslinkable compounds having three polymerizable unsaturated groups in the molecule such as propane or glycerin polyglycidyl ether poly (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (Meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol Rudi (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide bisphenol A type di (meth) acrylate, propylene oxide bisphenol type di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin Di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, diglycidyl phthalate di (meth) acrylate or hydroxypivalic acid neo Crosslinkable compounds having two polymerizable unsaturated groups in the molecule, such as pentyl glycol di (meth) acrylate, in addition, 2-hydroxyethyl (meth) acrylate 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, 3-chloro-2 Crosslinkability having one polymerizable unsaturated group in the molecule such as hydroxypropyl (meth) acrylate, glycerin mono (meth) acrylate, 2- (meth) acryloyloxyethyl phosphate ester or N-methylol (meth) acrylamide Compounds and the like.

Furthermore, a compound represented by the following formula [7A] can also be used.

(In the formula [7A], E ₁ represents a group selected from the group consisting of a cyclohexane ring, a bicyclohexane ring, a benzene ring, a biphenyl ring, a terphenyl ring, a naphthalene ring, a fluorene ring, an anthracene ring or a phenanthrene ring; ₂ represents a group selected from the following formula [7a] or [7b], and n represents an integer of 1 to 4.

The above is an example of a crosslinkable compound, but is not limited thereto. Moreover, the crosslinkable compound used for the liquid crystal aligning agent of this invention may be 1 type, or may combine 2 or more types.
The content of the crosslinkable compound in the liquid crystal aligning agent of the present invention is preferably 0.1 to 150 parts by mass with respect to 100 parts by mass of all polymer components. In particular, in order for the crosslinking reaction to proceed and to exhibit the desired effect, the amount is preferably 0.1 to 100 parts by mass with respect to 100 parts by mass of the polymer component. More preferred is 1 to 50 parts by mass.

As long as the effects of the present invention are not impaired, the liquid crystal aligning agent of the present invention can use a compound that improves the uniformity of the film thickness and surface smoothness of the liquid crystal aligning film when the liquid crystal aligning agent is applied.
Examples of the compound that improves the film thickness uniformity and surface smoothness of the liquid crystal alignment film include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants.

More specifically, for example, F-top EF301, EF303, EF352 (above, manufactured by Tochem Products), MegaFuck F171, F173, R-30 (above, manufactured by Dainippon Ink), Florard FC430, FC431 (or more) And Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (above, manufactured by Asahi Glass Co., Ltd.).

The amount of the surfactant used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of all the polymer components contained in the liquid crystal aligning agent.

Furthermore, the liquid crystal aligning agent is disclosed in International Publication No. WO2011 / 132751 (published 2011.10.27) on pages 69 to 73 as a compound that promotes charge transfer in the liquid crystal alignment film and promotes charge release of the device. Nitrogen-containing heterocyclic amine compounds represented by the formulas [M1] to [M156] can also be added. The amine compound may be added directly to the liquid crystal aligning agent, but it is preferable to add the amine compound after forming a solution having a concentration of 0.1 to 10% by mass, preferably 1 to 7% by mass. The solvent is not particularly limited as long as the specific polymer (A) is dissolved.

The liquid crystal aligning agent of the present invention includes, in addition to the above-mentioned poor solvent, crosslinkable compound, resin film or compound that improves the film thickness uniformity and surface smoothness of the liquid crystal aligning film, and a compound that promotes charge removal. As long as the effects of the invention are not impaired, a polymer other than the polymer described in the present invention, a silane coupling agent for the purpose of improving the adhesion between the alignment film and the substrate, and further when firing the coating film An imidization accelerator for the purpose of efficiently progressing imidization by heating of the polyimide precursor may be added to.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal alignment film is a film obtained by applying the above liquid crystal aligning agent to a substrate, drying and baking. The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used together with a glass substrate or a silicon nitride substrate. At that time, it is preferable to use a substrate on which an ITO electrode or the like for driving the liquid crystal is used from the viewpoint of simplification of the process. In the reflective liquid crystal display element, an opaque material such as a silicon wafer can be used as long as it is only on one side of the substrate, and a material that reflects light such as aluminum can be used for the electrode in this case.

The method for applying the liquid crystal aligning agent is not particularly limited, but industrially, a method performed by screen printing, offset printing, flexographic printing, an inkjet method, or the like is common. Other coating methods include a dipping method, a roll coater method, a slit coater method, a spinner method, or a spray method, and these may be used depending on the purpose.

After the liquid crystal aligning agent is applied on the substrate, the solvent can be evaporated by a heating means such as a hot plate, a thermal circulation oven, or an IR (infrared) oven to form a liquid crystal alignment film. Arbitrary temperature and time can be selected for the drying and baking steps after applying the liquid crystal aligning agent of the present invention. Usually, a condition of baking at 50 to 120 ° C. for 1 to 10 minutes and then baking at 150 to 300 ° C. for 5 to 120 minutes is mentioned in order to sufficiently remove the contained solvent. If the thickness of the liquid crystal alignment film after baking is too thin, the reliability of the liquid crystal display element may be lowered, and thus it is preferably 5 to 300 nm, and more preferably 10 to 200 nm.

The liquid crystal alignment treatment agent of the present invention is applied to a substrate, baked, and then subjected to an alignment treatment by a rubbing treatment, a rubbing treatment or a photo-alignment treatment performed by a conventional apparatus or method, or in a vertical alignment application. Without alignment treatment, it can be used as a liquid crystal alignment film.

As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. Note that the liquid crystal display element may be an active matrix structure in which switching elements such as TFTs (Thin Film Transistors) are provided in each pixel portion constituting the image display.

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

Next, a liquid crystal alignment film is formed on each substrate, the other substrate is overlapped with one substrate so that the liquid crystal alignment film faces each other, and the periphery is bonded with a sealant. In order to control the substrate gap, a spacer is usually mixed in the sealant, and it is preferable to spray a spacer for controlling the substrate gap on the in-plane portion where no sealant is provided. A part of the sealant 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 agent through the opening provided in the sealing agent, and then the opening is sealed with an adhesive. For the injection, a vacuum injection method may be used, or a method utilizing capillary action in the atmosphere may be used. As the liquid crystal material, either a positive liquid crystal material or a negative liquid crystal material may be used, but a negative liquid crystal material is preferable. Next, a polarizing plate is installed. Specifically, a pair of polarizing plates is attached to the surfaces of the two substrates opposite to the liquid crystal layer.

In a vertical alignment type (particularly PSA mode) liquid crystal display element, a line / slit electrode pattern of, for example, 1 μm to 10 μm is formed on one substrate, and a slit pattern or projection pattern is not formed on the counter substrate. The liquid crystal display element having this structure can simplify the manufacturing process and obtain high transmittance.

When manufacturing an IPS type or FFS type liquid crystal display element, an electrode forming surface of a substrate provided with an electrode made of a transparent conductive film or a metal film patterned in a comb shape, and a counter substrate provided with no electrode A liquid crystal aligning agent is apply | coated to one surface, respectively, Then, a coating film is formed by heating each application surface. As the metal film, for example, a film made of a metal such as chromium can be used.

The liquid crystal material constituting the liquid crystal layer of the vertical alignment type liquid crystal display element is not particularly limited, and liquid crystal materials used in the conventional vertical alignment method, for example, MLC-6608, MLC-6609, MLC-3022 manufactured by Merck & Co., Inc. Negative type liquid crystal such as can be used. In the PSA mode, MLC-3023 which is a liquid crystal containing a polymerizable compound can be used. In addition, for example, a liquid crystal containing a polymerizable compound represented by the following formula can be used.

On the other hand, the liquid crystal material constituting the liquid crystal layer of the horizontal alignment type liquid crystal display element such as IPS or FFS is not particularly limited, and liquid crystal materials conventionally used in the horizontal alignment type, such as MLC-2003 and MLC manufactured by Merck Negative-positive liquid crystals such as −2041 and negative-type liquid crystals such as MLC-6608 can also be used.

As a method for sandwiching the liquid crystal layer between two substrates, a known method can be exemplified. For example, a pair of substrates on which a liquid crystal alignment film is formed is prepared, and spacers such as beads are dispersed on the liquid crystal alignment film on one substrate so that the surface on which the liquid crystal alignment film is formed is on the inside. Then, the other substrate is bonded, and liquid crystal is injected under reduced pressure to seal. Also, a pair of substrates on which a liquid crystal alignment film is formed are prepared, and spacers such as beads are dispersed on the liquid crystal alignment film on one substrate, and then liquid crystal is dropped, and then the surface on which the liquid crystal alignment film is formed A liquid crystal cell can also be produced by a method in which the other substrate is bonded to each other so as to be inside, and sealing is performed. The thickness of the spacer is preferably 1 to 30 μm, more preferably 2 to 10 μm.

In the PSA mode method, after sandwiching the liquid crystal, a liquid crystal cell is produced by irradiating ultraviolet rays while applying a voltage to the liquid crystal alignment film and the liquid crystal layer. As this process, for example, a method of applying an electric voltage to the liquid crystal alignment film and the liquid crystal layer by applying a voltage between the electrodes installed on the substrate and irradiating ultraviolet rays while maintaining the electric field can be mentioned. Here, the voltage applied between the electrodes is, for example, 5 to 30 Vp-p or DC 2.5 to 15 V, preferably 10 to 30 Vp-p or DC 5 to 15 V. Further, as the light to be irradiated, ultraviolet rays containing light having a wavelength of 300 to 400 nm are preferable. The light source of the irradiation light is as described above. The irradiation amount of ultraviolet rays is, for example, 1 to 60 J, preferably 40 J or less, and the smaller the irradiation amount of ultraviolet rays, the lowering of reliability caused by the destruction of the members constituting the liquid crystal display element can be suppressed, and the irradiation time of ultraviolet rays can be reduced. This is preferable because the manufacturing efficiency is increased.

As described above, when ultraviolet rays are irradiated while applying a voltage to the liquid crystal alignment film and the liquid crystal layer, the polymerizable compound reacts to form a polymer, and the direction in which the liquid crystal molecules are tilted is stored by this polymer. Thus, the response speed of the obtained liquid crystal display element can be increased. In addition, a polyimide precursor having a side chain for vertically aligning liquid crystal and a photoreactive side chain when irradiated with ultraviolet rays while applying a voltage to the liquid crystal alignment film and the liquid crystal layer, and the polyimide precursor as an imide Since the photoreactive side chains of at least one polymer selected from the polyimide obtained by the reaction or the photoreactive side chains of the polymer react with the polymerizable compound, the liquid crystal display element obtained The response speed can be increased.

As described above, by using the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal aligning film excellent in the uniformity of the film thickness within the coating surface and the linearity and dimensional stability of the peripheral portion of the coating.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not construed as being limited to these examples.

The abbreviations of the compounds used are shown below.

(solvent)
NMP: N-methyl-2-pyrrolidone NEP: N-ethyl-2-pyrrolidone GBL: γ-butyrolactone BCS: butyl cellosolve PB: 1-butoxy-2-propanol DPM: dipropylene glycol monomethyl ether DIBK: diisobutyl ketone

(Tetracarboxylic dianhydride)
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 DC-5: 3,3,4,4-biphenyltetracarboxylic dianhydride

(Diamine)
DA-1: p-phenylenediamine DA-2: bis (4-aminophenoxy) ethane DA-3: 1,3-bis (4-aminophenoxy) propane DA-4: N-methyl-2- (4-amino Phenyl) ethylamine DA-5: Compound DA-6 represented by the following formula (DA-5): Compound DA-7 represented by the following formula (DA-6): Represented by the following formula (DA-7) Compound DA-8: Compound DA-9 represented by the following formula (DA-8) DA-9: 3,5-diaminobenzoic acid DA-10: Compound DA-11 represented by the following formula (DA-10) Compound DA-12 represented by (DA-11): Compound DA-13 represented by the following formula (DA-12): Compound DA-14 represented by the following formula (DA-13): Formula (DA Compound DA-15 represented by formula (-14): Compound DA-16 represented by 5): Compound DA-17 represented by the following formula (DA-16): Compound DA-18 represented by the following formula (DA-17): Formula (DA-18) Compound DA-19 represented by: Compound DA-20 represented by the following formula (DA-19): Compound DA-21 represented by the following formula (DA-20): Formula represented by the following formula (DA-21) Compound

(Additive)
3AMP: 3-picolylamine

In the chemical formula below, Me represents a methyl group, Bu represents an n-butyl group, and Boc represents a t-butoxy group.

The measuring method of each characteristic is as follows.

[viscosity]
The viscosity of the polyamic acid ester, the polyamic acid solution and the polyimide solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL (milliliter) and cone rotor TE-1 (1 ° 34 ′ R24) at a temperature of 25 ° C.

[Molecular weight]
The molecular weights of the polyamic acid ester and the polyamic acid were measured by a GPC (room temperature gel permeation chromatography) device, and converted into a polyethylene glycol (polyethylene oxide) conversion value as a number average molecular weight (hereinafter, also referred to as Mn) and a weight average molecular weight (hereinafter, Mw) was calculated.

GPC device: manufactured by Shodex (GPC-101)
Column: manufactured by Shodex (series of KD803 and KD805)
Column temperature: 50 ° C
Eluent: N, N-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H ₂ O) is 30 mmol / L (liter), phosphoric acid / anhydrous crystal (o-phosphoric acid) is 30 mmol / L, tetrahydrofuran (THF) is 10 ml / L)
Flow rate: 1.0 ml / min

Standard sample for preparing a calibration curve: TSK standard polyethylene oxide (weight average molecular weight (Mw) of about 900,000, 150,000, 100,000, and 30,000) manufactured by Tosoh Corporation and polyethylene glycol (peak top molecular weight manufactured by Polymer Laboratory) (Mp) of about 12,000, 4,000, and 1,000). In order to avoid overlapping of peaks, the measurement was performed by mixing four types of 900,000, 100,000, 12,000, and 1,000, and 3 of 150,000, 30,000, and 4,000. Two samples of mixed types were run separately.
<Synthesis Example 1>

In a 100 mL four-necked flask equipped with a stirrer and a nitrogen introduction tube, 0.81 g (7.5 mmol) of diamine DA-1, 1.22 g (5.0 mmol) of DA-2, and 1.94 g of DA-3 ( 7.5 mmol) and 1.99 g (5.0 mmol) of diamine DA-6, 74.86 g of NMP were added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 5.38 g (24.0 mmol) of tetracarboxylic dianhydride DC-1 was added, and NMP was further added so that the solid content concentration was 12% by mass. Stirring for a time gave a solution of polyamic acid (PAA-1).
The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 502 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 16,715 and Mw = 43,662.
<Synthesis Example 2>

In a 100 mL four-necked flask equipped with a stirrer and a nitrogen introducing tube, 6.26 g (21.0 mmol) of diamine DA-5 and 2.10 g (14.0 mmol) of diamine DA-4 were weighed and 76.28 g of NMP was measured. In addition, the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 6.58 g (33.6 mmol) of tetracarboxylic dianhydride DC-2 was added, and NMP was further added so that the solid content concentration was 15% by mass. By stirring, a solution of polyamic acid solution (PAA-2) was obtained.
The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 768 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 11,658 and Mw = 28,328.

In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 0.84 g (7.8 mmol) of diamine DA-1, 1.27 g (5.2 mmol) of DA-2, and 2.01 g of DA-3 ( 7.8 mmol) and 1.55 g (5.2 mmol) of diamine DA-5 were added, 73.26 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 5.42 g (24.2 mmol) of tetracarboxylic dianhydride DC-1 was added, and NMP was further added so that the solid content concentration was 12% by mass. Stirring for a time gave a solution of polyamic acid (PAA-3).
The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 393 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 14,654 and Mw = 39,268.

<Synthesis Example 4>
In a 3 L four-necked flask equipped with a stirrer and a nitrogen introduction tube, 17.30 g (159.98 mmol) of diamine DA-1, 58.63 g (240.0 mmol) of diamine DA-2, and 76. 89 g (240.0 mmol) and 54.63 g (159.99 mmol) of diamine DA-7 were weighed, 2458.13 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 171.27 g (764.02 mmol) of tetracarboxylic dianhydride DC-1 was added, and NMP was further added so that the solid content concentration was 12% by mass. Stirring for a time gave a solution of polyamic acid (PAA-4).
The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 426 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 12,380 and Mw = 33,250.

2250.0 g of this polyamic acid solution was collected, 750.0 g of NMP was added, 171.1 g of acetic anhydride and 35.4 g of pyridine were added, and the mixture was reacted at 55 ° C. for 3 hours. This reaction solution was poured into 9619.2 g of methanol, and the produced precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ° C. to obtain a polyimide powder. The imidation ratio of this polyimide was 66%. 880.0 g of NMP was added to 120.0 g of the obtained polyimide powder, and dissolved by stirring at 70 ° C. for 20 hr to obtain a polyimide solution (SPI-1).
The viscosity of this polyimide solution at a temperature of 25 ° C. was 137 mPa · s. Moreover, the molecular weight of this polyimide was Mn = 11,035 and Mw = 27,887.

<Synthesis Example 5>
In a 3 L four-necked flask equipped with a stirrer and a nitrogen introduction tube, 107.71 g (656.0 mmol) of diamine DA-21 and 24.95 g (163.98 mmol) of diamine DA-9 were weighed and 171.60 g of NMP was measured. In addition, the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 226.78 g (770.8 mmol) of tetracarboxylic dianhydride DC-5 was added, NMP was further added so that the solid content concentration was 12% by mass, and 4 hours at room temperature. By stirring, a solution of polyamic acid solution (PAA-4) was obtained.
The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 234 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 9,657 and Mw = 22,975.

<Synthesis Example 6>
In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 4.03 g (16.5 mmol) of diamine DA-2, 3.59 g (9.0 mmol) of diamine DA-6, and 2 diamine DA-18 were added. After adding 50 g (4.5 mmol), 102.1 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this solution, 4.37 g (19.5 mmol) of tetracarboxylic dianhydride DC-1 and 12.8 g of NMP were added, and the mixture was stirred at 40 ° C. for 3 hours. Thereafter, 1.71 g (8.7 mmol) of tetracarboxylic dianhydride DC-2 and 12.8 g of NMP were added at 25 ° C., and the mixture was further stirred for 12 hours, whereby the resin solid content concentration was 15 mass. % Polyamic acid solution was obtained.
The viscosity of this polyamic acid solution was 820 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 13,250 and Mw = 35,459.

80.0 g of this polyamic acid solution was collected, 70.0 g of NMP was added, 6.8 g of acetic anhydride and 1.8 g of pyridine were added, and the mixture was reacted at 50 ° C. for 3 hours. This reaction solution was poured into 555.0 g of methanol, and the produced precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ° C. to obtain a polyimide powder. The imidation ratio of this polyimide was 75%. NMP586.7g was added to 80.0g of obtained polyimide powder, and it stirred for 20 hours and dissolved at 50 degreeC, and the polyimide solution (SPI-2) was obtained.
The viscosity of this polyimide solution at a temperature of 25 ° C. was 74.0 mPa · s. Moreover, the molecular weight of this polyimide was Mn = 9,848 and Mw = 23,058.

<Synthesis Example 7>
In a 100 mL four-necked flask equipped with a stirrer and a nitrogen introduction tube, 1.12 g (4.5 mmol) of diamine DA-20, 0.59 g (3.0 mmol) of diamine DA-19, and 1 of diamine DA-21 After adding .49 g (7.5 mmol), 31.0 g of a mixed solvent of NMP: GBL = 1: 1 was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this solution, 1.15 g (5.9 mmol) of tetracarboxylic dianhydride DC-2 and 10.0 g of a mixed solvent of NMP: GBL = 1: 1 were added, And stirred for 1 hour. Thereafter, 2.60 g (8.8 mmol) of tetracarboxylic dianhydride DC-5 was added, 10.0 g of a mixed solvent of NMP: GBL = 1: 1 was added, and the mixture was further stirred at 50 ° C. for 12 hours. As a result, a polyamic acid solution (PAA-5) having a resin solid content concentration of 12% by mass was obtained.
The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 200 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 8,026 and Mw = 18,458.

<Synthesis Example 8>
After adding 25.20 g (0.088 mol) of diamine DA-16 and 8.72 g (0.022 mol) of diamine DA-17 to a 500 mL flask equipped with a stirrer and a nitrogen introduction tube, add 334.28 g of NMP. And dissolved by stirring. While stirring this solution under water cooling, 23.06 g (0.11 mol) of tetracarboxylic dianhydride DC-4 was added, and 83.57 g of NMP was further added, followed by stirring at 50 ° C. for 12 hours to obtain a polyamic acid solution. (PAA-6) was obtained.
The viscosity of this polyamic acid solution was 545 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 17,344 and Mw = 43,383.

<Synthesis Example 9>
After adding 23.91 g (0.12 mol) of diamine DA-21 and 4.56 g (0.03 mol) of diamine DA-9 to a 500 mL flask equipped with a stirrer and a nitrogen introduction tube, add 241.76 g of NMP. And dissolved by stirring. While stirring this solution under water cooling, 13.71 g (0.070 mol) of tetracarboxylic dianhydride DC-2 was added, and 69.07 g of NMP was further added, followed by stirring for 2 hours. Thereafter, 18.77 g (0.075 mol) of tetracarboxylic dianhydride DC-3 was added, 34.54 g of NMP was added, and the mixture was stirred at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-7). .
The viscosity of this polyamic acid solution was 300 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 11,333 and Mw = 24,081.

[Preparation of liquid crystal aligning agent]
Example 1
In a 40 ml sample tube containing a stir bar, 4.00 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 4.80 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 2 were weighed. Weighed 23.20 g of NMP, 6.80 g of PB and 1.20 g of DIBK and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent A1.

Using this liquid crystal alignment agent A1, the viscosity at 25 ° C. was measured. Thereafter, the following applicability evaluation was performed.

[Inkjet applicability evaluation]
Liquid crystal aligning agent A1 adjusted above was apply | coated on the glass substrate by which chromium was vapor-deposited on the surface using the inkjet coating device (made by Hitachi Plant Technology Co., Ltd.). The coating conditions were a discharge pitch of 40 μm, a coating speed of 100 mm / sec, an injection voltage of 13.0 V, and a coating area of 36 × 80 mm. The film thickness of the coating film was applied under the conditions of 100 nm when baked in an IR oven at 230 ° C. for 30 minutes after being temporarily dried on an 80 ° C. hot plate for 2 minutes.

The coating film that was temporarily dried at 80 ° C. and baked at 230 ° C. was evaluated in four stages by comparing the degree of streaky unevenness generated due to insufficient coating properties or dripping. Lv4 is a material that can be visually confirmed to have a noticeable unevenness on the entire surface, Lv3 is a material that can be visually confirmed to be partially uneven, Lv2 is a material that cannot be seen visually, and Lv1 is an image that has no unevenness even on an optical microscope.

Silicone-based water repellent film OA-160R1 (manufactured by Nissan Chemical Industries, Ltd.) was dropped on a 10 × 10 cm glass substrate and spin-coated on the glass substrate at a rotational speed of 2000 rpm. Thereafter, this glass substrate was baked in an IR oven at 200 ° C. for 30 minutes to obtain a hydrophobic glass substrate.

[Dot application evaluation]
About liquid crystal aligning agent A1 adjusted above, it apply | coated on the hydrophobic glass substrate prepared above using the inkjet coating apparatus (made by Hitachi Plant Technology). The coating conditions were a discharge pitch of 500 μm, a coating speed of 100 mm / sec, an injection voltage of 13.0 V, and a coating area of 36 × 80 mm. After apply | coating liquid crystal aligning agent A1 on the said conditions, after performing temporary drying for 2 minutes on an 80 degreeC hotplate, it baked by IR oven on the conditions for 230 degreeC for 30 minutes.

[Evaluation method of coating film]
About the dot-shaped coating film which was temporarily dried at 80 degreeC and baked at 230 degreeC, the diameter of the dot was measured using the microscope. In general, the larger the dot diameter, the better the coating material. A dot diameter of 160 μm or more was considered good, and less than that was considered bad.

<Examples 2 to 9 and Comparative Examples 1 to 9>
The polyamic acid solutions obtained in Synthesis Examples 1 to 3, 5, and 7 to 9 and the polyimide solutions obtained in Synthesis Examples 4 and 6 have the predetermined blend ratio, solid content concentration, and solvent ratio shown in Table 1 below. Thus, the liquid crystal aligning agents A2 to A6 and the liquid crystal aligning agents B1 to B5, C1, D1, E1, F1, G1, H1, and I1 were obtained. The composition ratio of the polyamic acid solution, the polyimide solution and the solvent is shown in Table 1 together with Example 1.

In Table 1, the solid content composition and the weight ratio represent the mixing ratio (mass%) of each polymer. The composition and weight ratio of the solution represent the ratio (mass%) of each organic solvent to the whole polymer solution.

Table 2 summarizes the evaluation results and the like in Examples 1 to 9 and Comparative Examples 1 to 9.

<Synthesis Example 10>.
Tetracarboxylic dianhydride DC-3 (12.51 g, 50.0 mmol), diamine DA-7 (13.66 g, 40.0 mmol), diamine DA-11 (6.61 g, 20.0 mmol), diamine DA- 13 (17.39 g, 40.0 mmol) was dissolved in NMP (179.3 g), reacted at 60 ° C. for 5 hours, and then tetracarboxylic dianhydride DC-2 (9.61 g, 49.0 mmol). And NMP (59.8 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution.

After adding NMP to this polyamic acid solution (100 g) and diluting to 6.5% by mass, acetic anhydride (17.0 g) and pyridine (5.3 g) were added as an imidization catalyst and reacted at 70 ° C. for 3 hours. It was. This reaction solution was poured into methanol (1700 ml), and the resulting precipitate was filtered off. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (J). The imidation ratio of this polyimide was 76%, the number average molecular weight was 11000, and the weight average molecular weight was 38000.

NMP (27.0 g) was added to the obtained polyimide powder (J) (3.0 g), and dissolved by stirring at 70 ° C. for 20 hours. 3AMP (1 wt% NMP solution) 3.0g, NMP (2.0g), and BCS (50.0g) were added to this solution, and the liquid crystal aligning agent (J1) was obtained by stirring at room temperature for 5 hours.

<Synthesis Example 11>
Tetracarboxylic dianhydride DC-3 (12.51 g, 50.0 mmol), diamine DA-8 (11.87 g, 50.0 mmol), diamine DA-11 (9.91 g, 30.0 mmol), diamine DA- 14 (15.14 g, 20.0 mmol) was dissolved in NMP (177.1 g), reacted at 60 ° C. for 5 hours, and then tetracarboxylic dianhydride DC-2 (9.61 g, 49.0 mmol). And NMP (59.0 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution.

After adding NMP to this polyamic acid solution (100 g) and diluting to 6.5% by mass, acetic anhydride (17.2 g) and pyridine (5.3 g) were added as imidization catalysts, and the mixture was reacted at 70 ° C. for 3 hours. It was. This reaction solution was poured into methanol (1300 ml), and the resulting precipitate was filtered off. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (K). The imidation ratio of this polyimide was 71%, the number average molecular weight was 9000, and the weight average molecular weight was 24000.

NMP (27.0 g) was added to the obtained polyimide powder (K) (3.0 g), and dissolved by stirring at 70 ° C. for 20 hours. 3AMP (1 wt% NMP solution) 3.0g, NMP (2.0g), and BCS (50.0g) were added to this solution, and the liquid crystal aligning agent (K1) was obtained by stirring at room temperature for 5 hours.

<Synthesis Example 12>
Tetracarboxylic dianhydride DC-3 (12.51 g, 50.0 mmol), diamine DA-9 (6.10 g, 40.0 mmol), diamine DA-11 (6.61 g, 20.0 mmol), diamine DA- 13 (17.39 g, 40.0 mmol) was dissolved in NMP (156.6 g), reacted at 60 ° C. for 5 hours, and then tetracarboxylic dianhydride DC-2 (9.61 g, 49.0 mmol). And NMP (52.2 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution.

After adding NMP to this polyamic acid solution (100 g) and diluting to 6.5% by mass, acetic anhydride (19.5 g) and pyridine (6.0 g) were added as an imidization catalyst and reacted at 70 ° C. for 3 hours. It was. This reaction solution was poured into methanol (1300 ml), and the resulting precipitate was filtered off. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (L). The imidation ratio of this polyimide was 75%, the number average molecular weight was 16000, and the weight average molecular weight was 43,000.

NEP (27.0 g) was added to the obtained polyimide powder (L) (3.0 g), and dissolved by stirring at 70 ° C. for 20 hours. NEP (20.0g) and BCS (50.0g) were added to this solution, and the liquid crystal aligning agent (L1) was obtained by stirring at room temperature for 5 hours.

<Synthesis Example 13>
Tetracarboxylic dianhydride DC-3 (12.51 g, 50.0 mmol), diamine DA-9 (7.61 g, 50.0 mmol), diamine DA-11 (9.91 g, 30.0 mmol), diamine DA- 14 (15.14 g, 20.0 mmol) was dissolved in NMP (164.4 g), reacted at 60 ° C. for 5 hours, and then tetracarboxylic dianhydride DC-2 (9.61 g, 49.0 mmol). And NMP (54.8 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution.

After adding NMP to this polyamic acid solution (100 g) and diluting to 6.5% by mass, acetic anhydride (18.6 g) and pyridine (5.8 g) were added as an imidization catalyst, and the mixture was reacted at 70 ° C. for 3 hours. It was. This reaction solution was poured into methanol (1300 ml), and the resulting precipitate was filtered off. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (M). The imidation ratio of this polyimide was 71%, the number average molecular weight was 12000, and the weight average molecular weight was 29000.

NMP (27.0 g) was added to the obtained polyimide powder (M) (3.0 g) and dissolved by stirring at 70 ° C. for 20 hours. NEP (20.0g) and BCS (50.0g) were added to this solution, and the liquid crystal aligning agent (M1) was obtained by stirring at room temperature for 5 hours.

<Synthesis Example 14>
Tetracarboxylic dianhydride DC-3 (5.00 g, 20.0 mmol), diamine DA-9 (6.09 g, 40.0 mmol), diamine DA-10 (7.27 g, 30.0 mmol), diamine DA- 12 (11.42 g, 30.0 mmol) was dissolved in NMP (137.1 g), reacted at 60 ° C. for 5 hours, and then tetracarboxylic dianhydride DC-4 (4.36 g, 20.0 mmol). Then, tetracarboxylic dianhydride DC-2 (11.57 g, 59.0 mmol) and NMP (45.7 g) were added and reacted at 40 ° C. for 10 hours to obtain a polyamic acid solution.

After adding NMP to this polyamic acid solution (100 g) and diluting to 6.5% by mass, acetic anhydride (22.2 g) and pyridine (6.9 g) were added as an imidization catalyst and reacted at 50 ° C. for 3 hours. It was. This reaction solution was poured into methanol (1300 ml), and the resulting precipitate was filtered off. This deposit was wash | cleaned with methanol, and it dried under reduced pressure at 100 degreeC, and obtained the polyimide powder (N). The imidation ratio of this polyimide was 78%, the number average molecular weight was 18000, and the weight average molecular weight was 39000.

NMP (27.0 g) was added to the obtained polyimide powder (N) (3.0 g) and dissolved by stirring at 70 ° C. for 20 hours. 3AMP (1 wt% NMP solution) 3.0g, NMP (2.0g), and BCS (50.0g) were added to this solution, and the liquid crystal aligning agent (N1) was obtained by stirring at room temperature for 5 hours.

According to Synthesis Examples 10 to 14 as described above, liquid crystal aligning agents J1, K1, L1, M1 and N1 were obtained.

The following table shows the composition ratio of the acid dianhydride component and the diamine component used in Synthesis Examples 10-14.

<Synthesis Examples 15 to 23>
Further, using the polyimide powders (J to N) obtained in Synthesis Examples 10 to 14, liquid crystal aligning agents having the solvent compositions shown in Table 4 below were prepared by the same operations as in Synthesis Examples 3 to 7. .

<Example 10>
About liquid crystal aligning agent J2 and N3 obtained by the synthesis example 16 and the synthesis example 20, it stirred at room temperature for 3 hours so that the weight ratio of the resin composition contained in each might be set to 3: 7, and liquid crystal aligning agent (JN1) Was prepared.

<Examples 11 and 12, Comparative Examples 10 to 14>
Each liquid crystal aligning agent was mix | blended by the same operation as Example 10, and the various liquid crystal aligning agents shown in following Table 5 were prepared. Table 5 shows the blending ratio and solvent composition of the prepared liquid crystal aligning agent.

The liquid crystal aligning agent in Table 5 was evaluated in the same manner as in Example 1. The evaluation results were as shown in Table 6.

From the results in Table 6, when Comparative Example 10 and Comparative Example 11 and Comparative Examples 12 and 13 are compared, if the polymer contains a protective group that is released by heat, uneven coating and dot coating properties tend to decrease. You can see that

On the other hand, when Example 10 and Comparative Example 10, Example 11 and Comparative Example 12, and Example 12 and Comparative Example 14 are compared, diisobutylketone is introduced, so that the polymer contains a protecting group that is eliminated by heat. It was confirmed that the coatability can be improved even when the film is exposed.

Claims

A polymer containing a protecting group which is at least one selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product thereof, and is desorbed by heat;
The liquid crystal aligning agent characterized by including the solvent component containing the solvent of the following A group, the solvent of B group, and isobutyl ketone.
Group A: at least one solvent selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone and 1,3-dimethylimidazolidinone Group B: butyl cellosolve, 1-butoxy -At least one solvent selected from the group consisting of 2-propanol, 2-butoxy-1-propanol, and dipropylene glycol dimethyl ether.
2. The liquid crystal aligning agent according to claim 1, wherein the amount of the solvent belonging to the A group is 20% by mass to 90% by mass or less with respect to the total mass of the liquid crystal aligning agent.
3. The liquid crystal aligning agent according to claim 1, wherein the amount of the solvent belonging to the group B is 1% by mass to 50% by mass or less with respect to the total mass of the liquid crystal aligning agent.
The liquid crystal aligning agent according to any one of claims 1 to 3, wherein the amount of the diisobutyl ketone is 1% by mass to 20% by mass or less based on the total mass of the liquid crystal aligning agent.
The liquid crystal aligning agent according to any one of claims 1 to 4, wherein the polymer contains the following structure.

Where
X 1 is an oxygen atom or a sulfur atom, A 1 to A 3 are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and the total number of carbon atoms is 1 to 9. * Represents a bond with another atom.
The polymer is at least one selected from the group consisting of a diamine component containing a diamine containing the structure of the above formula (a) and a polyimide precursor which is a reaction product of a tetracarboxylic acid derivative and an imidized product thereof. The liquid crystal aligning agent according to any one of claims 1 to 6, which is a polymer.
The liquid crystal aligning agent according to any one of claims 1 to 6, wherein the diamine containing the structure of the formula (a) is at least one selected from the following diamines.
The liquid crystal aligning agent according to claim 6 or 7, wherein the diamine containing the structure of the above formula (a) is 10 mol% to 50 mol% in the total diamine component.
A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 8.
A liquid crystal display device comprising the liquid crystal alignment film of claim 9.