TW201945526A - Novel liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element - Google Patents

Abstract

The invention provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element that can obtain a liquid crystal display element with excellent voltage holding characteristics and high temperature and high humidity resistance.
A liquid crystal alignment agent comprising a polymer (P) having a partial structure represented by the following formula (I-1) or formula (I-2).

(A represents a (n + 1) -valent hydrocarbon group having 1 to 18 carbon atoms, or a carbon-carbon bond of a hydrocarbon group having a -O-, -COO-, -CO-, or -NHCO- group. S represents a single bond Or a hydrocarbon group having 1 to 4 carbon atoms. P ₁ represents a hydroxyl group protected by a thermally dissociable group. N is an integer of 1 to 5; m is an integer of 1 to 2; when m is 1, R ₁ represents a carbon number of 1 to 4 In the hydrocarbon group, when m is 2, R ₁ represents a hydrogen atom. * Represents a bonding bond to a hydrocarbon group).

Description

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

The invention relates to a liquid crystal alignment agent capable of preparing a liquid crystal display element having excellent voltage holding characteristics and high temperature and high humidity resistance, and a liquid crystal alignment film and a liquid crystal display element using the same.

Liquid crystal display elements are widely used in display parts of personal computers, mobile phones, smart phones, and televisions. The liquid crystal display element includes, for example, a liquid crystal layer sandwiched between the element substrate and the color filter substrate, a pixel electrode and a common electrode that apply an electric field to the liquid crystal layer, a liquid crystal alignment film that controls the alignment of liquid crystal molecules in the liquid crystal layer, and opening and closing. Thin film transistors (TFTs), etc. that supply electrical signals for pixel electrodes.
In the past, with the high definition of liquid crystal display elements, requirements such as reduction of contrast of liquid crystal display elements or reduction of afterimages have been required. In liquid crystal alignment films, in addition to having excellent liquid crystal alignment, stable pre-production In addition to the inclination angle, characteristics such as suppression of high voltage retention, residual phenomenon caused by AC drive, rapid relaxation of a small amount of residual charge generated when a DC voltage is applied, and / or residual charge accumulated by a DC voltage are used to Increasingly becoming an important feature.

Conventionally, a liquid crystal alignment film is generally a liquid crystal alignment agent that uses a polyimide precursor such as polyamide acid or a solution of a soluble polyimide as a main component, and is coated on a glass substrate, etc. A polyfluorene-based liquid crystal alignment film obtained by sintering.
In response to the above requirements, various proposals have been made regarding polyimide-based liquid crystal alignment films. For example, a liquid crystal alignment film capable of shortening the disappearance time of the afterimage phenomenon caused by a DC voltage is a liquid crystal containing a tertiary amine with a specific structure in addition to a polyamic acid or a polyimide containing a polyimide group. An alignment agent (for example, Patent Document 1) or a liquid crystal alignment agent (for example, Patent Document 2) containing a soluble polyfluorene imine using a specific diamine compound having a pyridine skeleton or the like as a raw material. In addition, the liquid crystal alignment film has a high voltage retention rate and can shorten the disappearance time of the afterimage phenomenon caused by the DC voltage. In addition, a liquid crystal alignment film containing a very small amount of polyimide or its imidized polymer is used. A liquid crystal alignment agent for a compound selected from the group consisting of a compound containing a carboxylic acid group in the molecule, a compound containing a carboxylic acid anhydride group in the molecule, and a compound containing a tertiary amine group in the molecule (for example: Patent Document 3).

Also, for liquid crystal alignment films that have excellent liquid crystal alignment, high voltage retention, low afterimage phenomenon, and high reliability, and have a high pretilt angle, it is known to use a compound containing A liquid crystal alignment agent of a polyfluorinated acid or a fluorinated imidized polymer of a tetracarboxylic dianhydride of cyclobutane and a specific diamine compound (for example, Patent Document 4). In addition, in a liquid crystal display element driven by a transverse electric field, a method of suppressing the afterimage phenomenon caused by AC driving has been proposed, and a specific liquid crystal alignment film having good liquid crystal alignment and liquid crystal molecules having greater interaction has been proposed Method (Patent Document 5).
[Prior technical literature]
[Patent Literature]

[Patent Document 1] Japanese Unexamined Patent Publication No. 9-316200
[Patent Document 2] Japanese Patent Application Laid-Open No. 10-104633
[Patent Document 3] Japanese Unexamined Patent Publication No. 8-76128
[Patent Document 4] Japanese Patent Laid-Open No. 9-138414
[Patent Document 5] Japanese Unexamined Patent Publication No. 11-38415

[Problems to be solved by the invention]

However, in recent years, with the increase in the performance of liquid crystal display elements such as smart phones, expectations for the characteristics of liquid crystal alignment films have been increasing, especially for those that can be produced at high energy levels, even under long-term high temperature and high humidity. Demand for a liquid crystal alignment agent for a liquid crystal display element that can also maintain adhesiveness with a substrate and also maintain characteristics such as high voltage. In addition, in recent years, the manufacturing process of liquid crystal display elements has become extremely large. Therefore, in the manufacturing process of liquid crystal alignment films, nonuniformity in sintering temperature, nonuniformity in coating, and the like are extremely easy to occur. Therefore, the liquid crystal display element of the vertical alignment method also requires a high vertical alignment capability that can withstand severe processes.

The present invention is made in view of the above circumstances, and proposes a liquid crystal display device capable of producing a liquid crystal display element having adhesion to a substrate, voltage holding characteristics, and high temperature and high humidity resistance at a higher energy level. The purpose is an alignment agent, a liquid crystal alignment film using the same, and a liquid crystal display element. Another object is to provide a liquid crystal alignment film with a high vertical alignment ability that can generate a stable pretilt angle under a severe manufacturing process.

[Solution to the problem]

The inventors have conducted intensive research on achieving the above-mentioned object, and found that a liquid crystal alignment agent containing a polymer having a specific partial structure is extremely effective in achieving the above-mentioned object, and thus completed the present invention.

That is, the present invention has the following main contents.
(1) A liquid crystal alignment agent comprising a polymer (P) having a partial structure represented by the following formula (I-1) or formula (I-2).

(A represents a (n + 1) -valent hydrocarbon group having 1 to 18 carbon atoms, or a carbon-carbon bond of a hydrocarbon group having a -O-, -COO-, -CO-, or -NHCO- group; S represents a single Bond or hydrocarbon group of 1 to 4 carbons; P ₁ represents a hydroxyl group protected by a thermally dissociable group; n is an integer of 1 to 5; m is an integer of 1 to 2; when m is 1, R ₁ represents a carbon number of 1 to For a hydrocarbon group of 4 and m is 2, R ₁ represents a hydrogen atom. * Represents a bonding bond to a hydrocarbon group).
(2) The liquid crystal alignment agent according to the above (1), wherein the polymer (P) further has an amine group protected by a thermally dissociable group.
(3) The liquid crystal alignment agent according to the above (1) or (2), wherein the polymer (P) is obtained from a polyimide precursor and the polyimide precursor by amidation. Polyimide group of at least one selected polymer.
(4) The liquid crystal alignment agent according to any one of (1) to (3), wherein the polyfluorene imide precursor is one represented by the formula (I-1) or (I-2). Partial structure and a diamine having an amine group protected by a thermally dissociable group.
(5) The liquid crystal alignment agent according to the above (4), wherein the diamine is at least one selected from the diamines represented by the following formulae (II-1) to (II-3).

(L, M represent a divalent organic group, Q represents a trivalent organic group, n is an integer of 0 to 2; P represents a structure represented by the aforementioned formula (I-1) or formula (I-2); P ₂ (Represents an amine group protected by a thermally dissociable group).
(6) The liquid crystal alignment agent according to the above (5), wherein in the formulae (II-1) to (II-3), L and M represent an alkylene group having 1 to 11 carbon atoms and a bivalent Aliphatic ring structure or divalent aromatic ring structure; when any -CH ₂ -in the alkylene group is not a combination adjacent to each other, it can be replaced by -O-, -COO-, or -Si-O-Si- It may be substituted by a ring structure as shown below. R ₂ represents a hydrocarbon group of 1 to 5 carbon atoms.

(7) The liquid crystal alignment agent according to any one of the above (4) to (6), wherein the polyfluorene imide precursor may be formed by using the following formulas [S1] to [S3] The group is a polymer prepared by selecting a diamine having a side chain structure.

(X ¹ and X ² each independently represent a single bond,-(CH ₂ ) _a- (a is an integer from 1 to 15),
-CONH-, -NHCO-, -CON (CH ₃ )-, -NH-, -O-, -COO-,
-OCO- or-((CH ₂ ) _a1 -A ₁ ) _m1- ; wherein a plurality of a1 each independently represent an integer of 1 to 15, and each of a plurality of A ₁ independently represents an oxygen atom or -COO-; m ₁ is 1 ~ 2. G ¹ and G ² each independently represent a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms or a divalent alicyclic group having 3 to 8 carbon atoms. An arbitrary hydrogen atom on the aforementioned cyclic group may be composed of 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 At least one selected from the group consisting of a fluoroalkoxy group or a fluorine atom is substituted. m and n each independently represent an integer of 0 to 3, and the total of m and n is 1 to 4. R ¹ represents an alkyl group having 1 to 20 carbons, an alkoxy group having 1 to 20 carbons, or an alkoxyalkyl group having 2 to 20 carbons; any hydrogen forming R ¹ may be substituted with fluorine).

(X ³ represents a single bond, -CONH-, -NHCO-, -CON (CH ₃ )-, -NH-,
-O-, -CH ₂ O-, -COO-, or -OCO-; R ² represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms; any hydrogen that forms R ² may be replaced by Replaced by fluorine).

(X ⁴ represents -CONH-, -NHCO-, -O-, -COO-, or -OCO-; R ³ represents a structure having a cholesterol skeleton).
(8) The liquid crystal alignment agent according to any one of (1) to (7), wherein the thermally dissociable group is a group substituted with a hydrogen atom at 150 to 300 ° C.
(9) The thermally dissociable group is t-butoxycarbonyl.
(10) The liquid crystal alignment agent according to any one of the above (1) to (8), wherein the liquid crystal alignment film is formed of the liquid crystal alignment agent according to any one of the above (1) to (9). .
(11) A liquid crystal display element comprising the liquid crystal alignment film according to the above (10).

[Effect of the invention]

According to the present invention, a liquid crystal alignment film having good adhesion to a substrate can be obtained even under long-term high temperature and high humidity, and when the liquid crystal alignment agent of the present invention is used, it can be prepared during a long storage period. A liquid crystal display element that also has excellent voltage holding characteristics and high temperature and high humidity resistance. In addition, even when the sintering process is excessively applied, a liquid crystal display element that exhibits good vertical alignment can be provided.

[Form of Implementing Invention]

[Polymer (P)]
The liquid crystal alignment agent of the present invention is a polymer (also referred to as a polymer (P) in the present invention) having a partial structure represented by the following formula (I-1) or formula (I-2).

In the above formulae (1-1) and (1-2), the definitions of A, S, R ₁ , P ₁ , n, m, and * are as described above.

And, P _1, the on again preferably at 150 ~ 300 ℃, most preferably formed on the dissociation between 180 ~ 250 ℃, is substituted by hydrogen thermally dissociable group is preferred. Preferred specific examples include t-butoxycarbonyl, benzyloxycarbonyl, 9-fluorenylmethyloxycarbonyl, allyloxycarbonyl, or the following formulae (t-1) to (t-8) ). In the following formula, * represents a bond with an oxygen atom.

Among them, from the viewpoint of making P ₁ highly dissociative to heat, t-butoxycarbonyl (Boc), benzyloxycarbonyl, 9-fluorenylmethyloxycarbonyl, or allyloxycarbonyl is preferred, and more Preferred is t-butoxycarbonyl, or 9-fluorenylmethyloxycarbonyl.

The polymer (P) preferably has an amine group protected by a thermally dissociable group. When the amine group is protected by a thermally dissociable group, the resulting liquid crystal alignment film can have higher temperature and humidity resistance.
The thermally dissociable group of the protected amine group is a thermally dissociable group which is dissociated by heat and replaced by hydrogen. Among them, it is preferably 150 to 300 ° C, and most preferably 180 to 250 ° C. A thermally dissociable group substituted by hydrogen is preferred. This preferable specific example includes the same content as the thermally dissociable group for protecting the hydroxyl group.
Among them, from the viewpoint of improving the dissociation generated by heating, P _{1 is} preferably t-butoxycarbonyl (Boc), benzyloxycarbonyl, 9-fluorenylmethyloxycarbonyl, or allyloxycarbonyl, and more preferably Preferred is t-butoxycarbonyl, or 9-fluorenylmethyloxycarbonyl.

The main skeleton of the polymer (P) is not particularly limited, and may be, for example, a polyimide precursor, polyimide, polysiloxane, polyester, polyimide, a cellulose derivative, a polymer Main skeletons of acetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate, and the like. The (meth) acrylate is intended to include acrylate and methacrylate. Polyamidide precursors, such as polyamidide, polyamidate, and the like. The polymer (P) may be used alone or in combination of two or more.

The polymer (P) is selected from the group consisting of polyimide precursors, polyimide, polyimide, polyorganosiloxane, poly (meth) acrylate, and polyester. At least one is preferred, and at least one polymer selected from the group consisting of a polyimide precursor and a polyimide is more preferred.

[Specific diamine]
The polyimide precursor and / or polyimide of the polymer (P) may have a partial structure represented by the above formula (I-1) or (I-2), and preferably has thermal dissociation. It is prepared by the amino group-protected amine diamine (also referred to as a specific diamine in the present invention).
In the present invention, when a specific diamine is used, a liquid crystal alignment film having a high vertical alignment ability that produces a stable pretilt angle can be produced even in a severe device manufacturing process, but its action mechanism has not yet been clarified. However, it is presumed to be the effect obtained by heating a specific diamine to deprotect it and generate a hydroxyl group. In general, it is known that a hydroxyl group causes a cross-linking reaction with a carboxylic acid present in polyimide, and this reaction is widely used in practical cross-linking agents and the like. It is presumed that the present invention uses a specific diamine to perform a cross-linking reaction of a polyimide-based polymer through a deprotection reaction by heating, so that the polymer or a side chain structure having a vertical alignment ability can be stabilized. Even under severe sintering conditions, the vertical alignment will not be reduced.

The specific diamine is preferably at least one selected from the group consisting of the following formulae (II-1) to (II-3).

In the formulae (II-1) to (II-3), L and M represent a divalent organic group, Q represents a trivalent organic group, and n is an integer of 0 to 2. P represents the aforementioned formula (I-1) Or a structure represented by formula (I-2); P ₂ represents an amine group protected by a thermally dissociable group.
The L and M each independently represent an alkylene group having 1 to 11 carbon atoms, a divalent aliphatic ring structure, or a divalent aromatic ring structure. When any -CH ₂ -in the above alkylene is a combination that is not adjacent to each other, it may be replaced by -O-, -COO-, or -Si-O-Si-, or may be replaced by a ring structure as shown below. . R ₂ represents a hydrocarbon group of 1 to 5 carbon atoms.

Specific examples of the diamine used for producing the polymer (P) include the following formulas [M-1] to [M-34] and the like. Moreover, a diamine can be used individually by 1 type or in combination of 2 or more types.

[Tetracarboxylic acid component]
The polyamidic acid of the polyamidoimide precursor of the polymer (P) can be prepared by a polycondensation reaction of the above-mentioned specific diamine and a tetracarboxylic acid component.
Examples of the tetracarboxylic acid component include, for example, tetracarboxylic acid, tetracarboxylic dianhydride, tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl dihalide.

Examples of the tetracarboxylic dianhydride include, for example, aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride. These specific examples are, for example, those listed in the following groups [1] to [5].

[1] Aliphatic tetracarboxylic dianhydride, for example: 1,2,3,4-butanetetracarboxylic dianhydride and the like.
[2] An alicyclic tetracarboxylic dianhydride, for example, acid dianhydrides such as the following formulae (X1-1) to (X1-13).

In the formulae (X1-1) to (X1-4), R ₃ to R ₂₃ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, and 2 carbon atoms. An alkynyl group of 6 to 6 and a monovalent organic group of 1 to 6 carbon atoms containing a fluorine atom or a phenyl group. R _M represents a hydrogen atom or a methyl group. In the formula (X1-13), Xa represents a tetravalent organic group represented by the following formulae (Xa-1) to (Xa-7).

[3] 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione), 3,5,6-tri Carboxy-2-carboxymethyl norbornane-2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10 -Tetraketones, etc.

[4] Aromatic tetracarboxylic dianhydride, such as pyromellitic anhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride, 3,3', 4,4'-diphenylhydrazone Tetracarboxylic dianhydride, acid dianhydrides represented by the following formulae (Xb-1) to (Xb-10), and (Xb-1) to (Xb-10) below.

[5] An acid dianhydride represented by the following formulae (X1-44) to (X1-52), a tetracarboxylic dianhydride described in Japanese Patent Application Laid-Open No. 2010-97188, and the like.

These tetracarboxylic acid components may be used singly or in combination of two or more kinds. According to the characteristics required for a liquid crystal alignment film or a liquid crystal display element, one type may be used alone or two or more types may be used in combination, and when two or more types are used in combination, the proportion and the like may be appropriately adjusted.

(Other diamines)
The diamine used in the production of the polymer (P) has a side chain structure selected from the group represented by the following formulas [S1] to [S3] (hereinafter, also referred to as "diamine") in addition to the specific diamine described above. Is a diamine having a specific side chain structure); a diamine having a function of generating polymerization or generating a radical upon irradiation with light; a diamine described in paragraph 0169 of International Publication WO2015 / 046374; a carboxy group described in paragraphs 0171 to 0172; Diamine having a hydroxyl group, diamine having a nitrogen-containing heterocyclic ring described in paragraphs 0173 to 0188, or diamine having a nitrogen-containing structure described in paragraph 0050 of Japanese Patent Application Laid-Open No. 2016-218149, 1,3-bis (3-amine Propyl) -1,1,3,3-tetramethyldisilaxane, 1,3-bis (4-aminobutyl) -1,1,3,3-tetramethyldisilaxane Diamines containing organosiloxane and the like. A polymer prepared by using a diamine having a specific side chain structure as at least a part of a raw material is preferable from the viewpoint of improving the heat resistance of a liquid crystal alignment film. Moreover, it is preferable that the improvement effect of the coating property (printability) of a liquid crystal aligning agent can be improved using the polymer which has at least one part of the diamine containing a carboxyl group as a raw material.

In the formula [S1], X ¹ and X ² each independently represent 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 -; wherein a plurality of a1 each independently represents an integer of 1 to 15, a plurality of A ₁ each independently represents an oxygen atom or -COO-; m ₁ is 1 to 2. G ¹ and G ² each independently represent a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms or a divalent alicyclic group having 3 to 8 carbon atoms. An arbitrary hydrogen atom on the aforementioned cyclic group may be composed of 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 At least one selected from the group consisting of a fluoroalkoxy group or a fluorine atom is substituted. m and n each independently represent an integer of 0 to 3, and the total of m and n is 1 to 4. R ¹ represents an alkyl group having 1 to 20 carbons, an alkoxy group having 1 to 20 carbons, or an alkoxyalkyl group having 2 to 20 carbons; any hydrogen forming R ¹ may be substituted with fluorine.

In the formula [S2], X ³ represents a single bond, -CONH-, -NHCO-,
-CON (CH ₃ )-, -NH-, -O-, -CH ₂ O-, -COO-, or -OCO-. R ² represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms; any hydrogen forming R ² may be substituted with fluorine.

(In formula [S3], X ⁴ represents -CONH-, -NHCO-, -O-, -COO- or
-OCO-. R ³ represents a structure having a cholesterol skeleton.

The diamine having a specific side chain structure is, for example, a diamine represented by the following formula [1] or formula [2]. These may be used alone or in combination of two or more.

In the above formula [2], X represents a single bond, -O-, -C (CH ₃ ) _2-
, -NH-, -CO-,-(CH ₂ ) _m- , -SO _2- , -O- (CH ₂ ) _m -O-, -OC (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-, or
-COO- (CH ₂ ) _m -OCO- is a divalent organic group. m is an integer from 1 to 8. Y represents a side chain structure represented by the above formulas [S1] to [S3].

Preferred specific examples of the formula [S1] include the following structures [S1-x1] to [S1-x7].

In the above formula, R ¹ represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. X ^p represents-(CH ₂ ) _a- (a is an integer from 1 to 15), -CONH-, -NHCO-, -CON (CH ₃ )-,
-NH -, - O -, - CH 2 O -, - CH 2 OCO -, - COO-, or -OCO-. A ₁ is an oxygen atom or -COO- * (where the bond with "*" is a bond with (CH ₂ ) _a2 ), A ₂ is an oxygen atom * -COO- (where "*" is attached The bond is bonded to (CH ₂ ) _a2 ), a ₁ and a ₃ are each independently an integer of 01, a ₂ is an integer of 1 to 10, and Cy is 1,4-cyclohexyl 1,4- Phenyl.

Preferred specific examples of the formula [S3] include the following formula [S3-x].

Specific examples of the diamine of the formula [1] include the following formulas [S-1] to [S-18] and the like.

(n represents an integer from 1 to 20).

Examples of the diamine represented by the formula [2] include structures selected from the group consisting of the following formulas [W-1] to [W-6].

In the above formula, X ^p1 to X ^p8 are each independently-(CH ₂ ) _a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH ₃ )-,
-NH-, -O-, -CH ₂ O-, -CH ₂ OCO-, -COO-, or -OCO-; X ^s1 to X ^s4 each independently represent -O-, -COO- or -OCO-; X _a to X _f
-O-, -NH-, -O- (CH ₂ ) _m -O-; R ^1a to R ^1h each independently represent an alkyl group having 1 to 20 carbon atoms and an alkoxy carbon number 2 to 1 to 20 20 alkoxyalkyl. m represents an integer from 1 to 8.
The diamine having a specific side chain structure is preferably 1 mol% or more, and more preferably 2 mol% or more, relative to the specific diamine. The content is preferably 90 mol% or less, and more preferably 85 mol% or less.

A diamine having a function of polymerizing upon irradiation with light, for example, a diamine having a structure represented by the following formulae [p1] to [p7], which is bonded to an aromatic ring such as a benzene ring via a direct linking group.

Specifically, for example, _a diamine represented by the following formula [P _a ] or [P _b ].

The bonding position of the two amine groups (-NH ₂ ) in the formula [P _a ] and the formula [P _b ] is from the viewpoint of reactivity, the position of the 2, 4 position, the position of the 2, 5 position, or 3 The 5th position is better. In addition to the simplicity when synthesizing diamines, the positions at positions 2, 4 or 3, 5 are preferred.

In the formula [P _a ], R ⁸ represents a single bond, -O-, -COO-,
-OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-, -N (CH ₃ )-,
-CON (CH ₃ )-, or -N (CH ₃ ) CO-; in terms of manufacturing simplicity, a single bond, -O-, -COO-, -NHCO-, or -CONH- is preferred.

R ⁹ represents a single bond, a divalent radical selected from an aromatic ring having 1 to 20 carbon atoms, a benzene ring, a naphthalene ring, and the like having a carbon number of 12 to 12, which may be substituted by a fluorine atom, and cyclohexane. A bivalent alicyclic group having 3 to 8 carbon atoms, such as a ring, consisting of pyrrole, imidazole, pyridine, pyrimidine, pyridine ,despair ,three , Indole, quinoline, carbazole, thiazole, purine, tetrahydrofuran, thiophene, and other 5-membered heterocyclic rings selected from bicyclic cyclic groups and the like. Among them,
-CH ₂ -may be optionally substituted by -CF ₂ -or -CH = CH-. In terms of ease of synthesis, a single bond or an alkylene group having 1 to 12 carbon atoms is preferred. k represents an integer from 0 to 4.
R ¹⁰ represents a structure selected from the above formulas [p1] to [p7]. From the viewpoint of photoreactivity, [p1], [p2], and [p4] are preferred.

In the formula [P _b ], Y ₁ and Y ₃ each independently represent -CH _2- ,
-O-, -CONH-, -NHCO-, -COO-, -OCO-, -NH-, or
-CO-. Y ₂ and Y ₅ each independently represent the same meaning as R ₉ in the above [Pa]; Y ₄ represents cinnamoyl. Y ₆ represents a structure selected by the above formulas [p1] to [p7]. From the viewpoint of photoreactivity, [p1], [p2], and [p4] are preferred. m represents 0 or 1.

A diamine having a function of polymerizing upon irradiation with light can be used for liquid crystal alignment, pretilt angle, voltage holding characteristics, charge accumulation characteristics, etc. when used as a liquid crystal alignment film, and liquid crystal response speed when used as a liquid crystal display element. They can be used singly or in combination of two or more.

The diamine having a function of polymerizing upon irradiation with light is preferably 1 mol% or more, and more preferably 2 mol% or more, relative to the total amount of the diamine used in the synthesis of the polymer (P). The upper limit of the usage ratio can be arbitrarily set within a range of 100 mol% or less. It is preferably 90 mol% or less, and more preferably 85 mol% or less.

A diamine having a function of generating a radical upon irradiation with light, for example, a diamine having a site having a radical generating structure that is decomposed by ultraviolet radiation to generate a radical on the side chain, and is represented by the following formula [R] Diamine and so on.

Ar, R ₁ , R ₂ , T ₁ , T ₂ , S, and Q in the above formula [R] have the following definitions.
That is, Ar represents an aromatic hydrocarbon group selected from a phenylene group, a naphthyl group, and a biphenylene group; among these, it may be substituted with an organic group, and a hydrogen atom may be substituted with a halogen atom. R ₁ and R ₂ each independently represent an alkyl group or an alkoxy group having 1 to 10 carbon atoms.
T ₁ and T ₂ each independently represent a single bond or -O-, -COO-, -OCO-,
-NHCO-, -CONH-, -NH-, -CH ₂ O-, -N (CH ₃ )-,
-CON (CH ₃ )-, -N (CH ₃ ) CO- bonding group.

S in the above formula [R] has the same meaning as R ⁹ in the above [P _a ];
Q represents a structure selected from the following formulas [q-1] to [q-4] (R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₃ represents -CH _2- , -NR-,- O-, or -S-).

(In the formula, * represents a bonding position).

In the above formula [R], Ar which is bonded to a carbonyl group is preferably a structure having a long conjugate length such as a naphthalene or a biphenyl group from the viewpoint of efficiently absorbing ultraviolet rays. In addition, Ar may be substituted with a substituent. The substituent is preferably an organic group having an electron injecting property such as an alkyl group, a hydroxyl group, an alkoxy group, or an amine group. When the wavelength of the ultraviolet rays is in the range of 250 nm to 380 nm, sufficient characteristics can be achieved even in the case of a phenyl group, so the phenyl group is the best.
When R ₁ and R ₂ are each independently an alkyl group, alkoxy group, benzyl group, or phenethyl group, alkyl group, or alkoxy group having 1 to 10 carbon atoms, R ₁ and R ₂ may form a ring.
Q is more preferably a hydroxy group or an alkoxy group.

The diaminobenzene in formula (R) may have any structure of o-phenylenediamine, m-phenylenediamine, or p-phenylenediamine. From the viewpoint of having high reactivity with tetracarboxylic acid components, m-phenylenediamine, or p-phenylenediamine is preferred.
Specifically, for example, from the viewpoints of ease of synthesis, high commonality, and characteristics, the structures represented by the following formulas [R-1] to [R-4] are most preferable. In the formula, n is an integer of 2 to 8.

The diamine having a function of generating radicals upon irradiation with light is preferably 1 mol% or more, and more preferably 2 mol% or more, relative to the total amount of the diamine used in the synthesis of the polymer (P). It is more preferably 5 mol% or more. The upper limit of the use ratio can be arbitrarily set within a range of 100 mol% or less. It is preferably 70 mol% or less, more preferably 60 mol% or less, and particularly preferably 50 mol% or less.

Preferred specific examples of the diamine other than the diamine having a specific side chain structure or a diamine having a function of polymerizing or generating a radical by irradiation with light include m-phenylenediamine, p-benzene Diamine, 4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diamine Biphenyl, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylamine, N-methyl (4,4'-di Aminodiphenyl) amine, 4,4'-diaminobenzophenone, 1,4-diaminonaphthalene, 2,6-diaminonaphthalene, 1,2-bis (4-aminephenyl ) Ethane, 1,3-bis (4-aminophenyl) propane, 1,4-bis (4-aminophenyl) butane, 1,4-bis (4-aminophenoxy) benzene, 1 1,4-bis (4-aminophenyl) benzene, 1,3-bis (4-aminephenyl) benzene, 1,4-bis (4-aminobenzyl) benzene, 1,3-bis (4- Aminophenoxy) benzene, 4,4 '-[1,4-phenylenebis (methylene)] diphenylamine, 1,4-phenylenebis [(4-aminophenyl) methanone] , 1,4-phenylene bis (4-aminobenzoate), bis (4-aminephenyl) terephthalate, bis (4-aminephenyl) isophthalate, N, N '-(1,4-phenylene) bis (4-aminobenzamide), N, N'- Bis (4-aminophenyl) p-phenylenediamine, N, N'-bis (4-aminophenyl) isophenylenediamine, 9,10-bis (4-aminephenyl) anthracene, 2,2 '-Bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-bis (4-aminophenyl) propane, 1,3-bis (4-aminophenoxy) propane , 1,4-bis (4-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane Alkane, 1,7-bis (4-aminophenoxy) heptane, 1,8-bis (4-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) Nonane, 1,10- (4-aminophenoxy) decane, bis (4-aminocyclohexyl) methane, 1,3-diaminopropane, 1,4-diaminobutane, 1 1,5-diaminopentane, 1,6-diaminohexane, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 4 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 4,4'-diaminodiphenylethane-3-carboxylic acid Acid, 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid, 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, 3,3'-diamine Biphenyl-4,4'-dicarboxylic acid, 3,3'-diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-diaminodiphenylmethane-3,3'- Dicarboxylic acid 4,4'-diaminodiphenylethane-3,3'-dicarboxylic acid, 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid, 2,6-diamine Pyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4- Bis- (4-aminophenyl) -piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diamine Carbazole, N, N'-bis (4-aminophenyl) -benzidine, N, N'-bis (4-aminephenyl) -N, N'-dimethylbenzidine, the following formula (D -2-1) to compounds (D-2-8), etc., respectively.

(Manufacture of Polyamic Acid)
The production of polyamic acid is usually carried out by using a diamine and a tetracarboxylic acid compound in a solvent. The solvent is not particularly limited as long as it can dissolve the polymer produced.

Specific examples of the solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone γ-butyrolactone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfonate 1,3-dimethyl-2-imidazolinone, and the like. When the polymer has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the following formulas [D-1] to A solvent represented by the formula [D-3].

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

These solvents may be used alone or in combination. Moreover, even if it is a solvent which does not melt | dissolve a polymer, if it is the range which does not precipitate the produced | generated polymer, it can mix and use with the said solvent. In addition, since the water in the solvent hinders the polymerization reaction and even causes the generated polymer to hydrolyze, it is preferable to use a solvent that is dehydrated and dried.

When the diamine and the tetracarboxylic acid compound are reacted in a solvent, the reaction can be performed at any concentration, but when the concentration is too low, it is difficult to obtain a high molecular weight polymer, and when the concentration is too high, the reaction solution is too viscous. High and difficult to achieve uniform stirring. Therefore, it is preferably 1 to 50% by mass, and more preferably 5 to 30% by mass. Alternatively, the reaction may be carried out at a high concentration at the beginning of the reaction, and thereafter, a solvent may be added.
In the polymerization reaction of the polymer (P), the ratio of the total mole number of the diamine to the total mole number of the tetracarboxylic acid compound is preferably 0.8 to 1.2. As with the usual polycondensation reaction, the closer the Mohr ratio is to 1.0, the larger the molecular weight of the specific polymer produced.

[Polyurethane]
Polyamidate precursors of polyimide, for example:
[I] a method of reacting polyamidic acid prepared by the above-mentioned synthesis reaction with an esterifying agent,
[II] A method for reacting a tetracarboxylic diester with a diamine,
[III] It is produced by a known method such as a method of reacting a tetracarboxylic diester dihalide with a diamine.

[Polyimide]
Polyimide is a polyimide obtained by forming a ring closure of the aforementioned polyimide precursor. In this polyimide, the ring closure rate (also called amidation rate) of the amido acid group is not necessary. It is 100%, and can be adjusted arbitrarily according to the purpose or purpose.
A method for imidizing a polyimide precursor, for example, by directly heating a solution of a polyimide precursor, and then adding a catalyst to the solution of the polyimide precursor. Mediator imidization and so on.
The temperature at which the polyfluorene imine precursor is thermally fluorinated in the solution is between 100 ° C and 400 ° C, preferably between 120 ° C and 250 ° C, and the water produced by the fluorination reaction is simultaneously It is better to exclude the reaction system.

As a catalyst for polyimide precursors, imidization can be performed by adding an alkaline catalyst and an acid anhydride to the solution of the polyimide precursors, and at -20 ° C to 250 ° C, preferably 0 ° C. Stirring is performed at a temperature of ~ 180 ° C. The amount of the alkaline catalyst is 0.5 to 30 mole times of the amino acid group, preferably 2 to 20 mole times, and the amount of the acid anhydride is 1 to 50 mole times of the amino acid group, preferably 3 to 30 mol times. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine can be used to maintain proper basicity during the reaction and is more preferred. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Among them, when acetic anhydride is used, purification is easily performed after completion of the reaction, and the like is preferred. The rate of catalyst imidization can be controlled by adjusting the amount of catalyst and the reaction temperature and reaction time.

When recovering the polyfluorene imide precursor polyfluorene imide from the reaction solution of the polyfluorene imine precursor polyfluorene imine, the reaction solution can be put into a solvent to precipitate. Examples of the solvent used for the precipitation include methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. After the polymer precipitated after adding the solvent is filtered and recovered, the polymer can be dried under normal pressure or reduced pressure, at normal temperature or under heating. In addition, after the polymer recovered by precipitation is re-dissolved in a solvent by repeating 2 to 10 times, and the polymer is re-precipitated and recovered, the impurities in the polymer can be reduced. Examples of the solvent at this time include alcohols, ketones, and the like. When three or more solvents selected from these contents are used, the viewpoint of improving the purification efficiency is even more preferable.

The polystyrene-equivalent weight-average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the polyimide precursor and polyimide is preferably 1,000 to 500,000, and more preferably 2,000 to 300,000. The molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC is preferably 15 or less, and more preferably 10 or less. In these molecular weight ranges, good alignment of the liquid crystal display element can be ensured.

When the liquid crystal alignment agent of the present invention contains the polymer (P), for the purpose of improving electrical characteristics or solution characteristics, the polymer (P) may contain other polymers (hereinafter, also referred to as other polymers) ). In this case, the proportion of other polymers used is preferably 80 parts by mass or less, more preferably 0.1 to 80 parts by mass, and 0.3 to 70 parts with respect to 100 parts by mass of the polymer contained in the liquid crystal alignment agent. Mass parts are particularly good.

The main skeleton of other polymers is not particularly limited, such as: polyimide precursors, polyimide, polysiloxane, polyester, polyimide, cellulose derivatives, polyacetal, polyacetal Main skeletons of styrene derivatives, poly (styrene-phenylmaleimide) derivatives, poly (meth) acrylates, and the like. Among them, at least one selected from the group consisting of polyimide precursors, polyimides, polyimides, polyorganosiloxanes, poly (meth) acrylates, and polyesters is preferred, At least one selected from the group consisting of a polyimide precursor, a polyimide, and a polysiloxane is preferred. Other polymers may be used singly or in combination of two or more kinds.

The liquid crystal alignment agent of the present invention may contain components other than the above if necessary. This component, for example: a compound having at least one epoxy group in the molecule, a compound having at least one oxycyclobutane group in the molecule, a functional silane compound, a metal chelate compound, a hardening accelerator, a surfactant, an antioxidant , Sensation, preservative, etc.

<Solvent>
The liquid crystal alignment agent of the present invention is prepared by dispersing or dissolving the polymer (P) and other components, if necessary, in an appropriate solvent to form a liquid composition.

Organic solvents used, for example: N-methyl-2-pyrrolidone, 1,3-dimethyl-imidazolidinone, 3-methoxy-N, N-dimethylpropanehydrazone, 3- Butoxy-N, N-dimethylpropaneamide, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol Methyl ether, ethylene glycol ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol monobutyl ether Ether ether acetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol mono Diethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, diisobutyl ketone, isoamyl propionate, isoamyl Isobutyrate, diisoamyl ether, ethylene carbonate, propylene carbonate, and the like. These can be used alone or in combination of two or more.

In the liquid crystal alignment agent, the solid content concentration (the ratio of the total mass of components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) can be appropriately selected after considering the viscosity and volatility. The range is preferably 1 to 10% by mass. From a viewpoint of forming a uniform and defect-free coating film, 1 mass% or more is preferable, and from a viewpoint of solution storage stability, 10 mass% or less is preferable. The concentration of the particularly preferred polymer is 2 to 8% by mass.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal alignment agent of the present invention is used as a liquid crystal alignment film after being sintered, and subjected to alignment treatment such as rubbing treatment or light irradiation. In addition, in the case of vertical alignment applications, it can be used as a liquid crystal alignment film without performing alignment processing. The substrate used at this time is not particularly limited as long as it is a substrate having high transparency. In addition to a glass substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate may be used. From the viewpoint of simplification of the process, it is preferable to use a substrate formed with an ITO electrode or the like that is driven by a liquid crystal. Moreover, in a reflective liquid crystal display element, if it is only a single-sided substrate, an opaque substrate such as a silicon wafer may be used. In this case, an electrode capable of reflecting light such as aluminum may be used.

The application method of the liquid crystal alignment agent may include, for example, screen printing, lithography, flexo printing, inkjet method, dipping method, roll coating method, slit coating method, spin coater method, and spraying. From the viewpoint of improving the production efficiency of the liquid crystal alignment film, a method using a relief printing method or an inkjet coating method is preferred.

After the liquid crystal alignment agent is coated on the substrate, heating means such as a hot plate, a thermal cycle type IR (infrared) type oven, and the solvent used for the liquid crystal alignment agent may be used, and it is preferably dried at 40 to 150 ° C. Secondly, it is preferred to form a liquid crystal alignment film by sintering at a temperature of 150 to 300 ° C, and more preferably at a temperature of 180 to 250 ° C. Among them, in the sintering treatment, the hydroxyl groups protected by the thermally dissociable group or the amine groups protected by the thermally dissociable group in the polymer (P) are dissociated due to the thermally dissociable group, respectively, resulting in unprotected groups. Hydroxyl or amine. The generated hydroxyl group or amine group reacts with a polyimide precursor or a carboxyl group or amidino group of polyimide to form a crosslinked structure. In this way, the obtained liquid crystal alignment film can have excellent high temperature and high humidity resistance or high voltage retention.
If the thickness of the sintered liquid crystal alignment film is too thick, it is disadvantageous from the viewpoint of power consumption of the liquid crystal display element. If it is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, it is preferably 5 to 300 nm, more preferably It is preferably 10 to 100 nm.

When the display mode of the obtained liquid crystal display element is VA type, the coating film formed as described above can be used immediately as a liquid crystal alignment film, but if necessary, a rubbing treatment or a PSA treatment described later may be performed. On the other hand, when the display mode of the prepared liquid crystal display device is a vertical electric field method or a transverse electric field method other than the VA type, the formed coating film surface may be subjected to a rubbing treatment or a polarized ultraviolet irradiation treatment to perform an alignment treatment. .

The liquid crystal alignment agent of the present invention is also suitably used for having a liquid crystal layer between a pair of substrates having electrodes, and a polymerizable compound containing at least one of an active energy ray and a heat treatment disposed between the pair of substrates. The liquid crystal composition is a liquid crystal display element obtained by applying at least one of an active energy ray irradiation and a heat treatment to a polymerizable compound while applying a voltage between the electrodes. The applied voltage may be, for example, a DC or AC voltage of 5 to 50V. The active energy rays are preferably ultraviolet rays. The ultraviolet rays are ultraviolet rays including light rays having a wavelength of 300 to 400 nm, and preferably ultraviolet rays having light rays having a wavelength of 310 to 360 nm. The light irradiation amount is preferably 0.1 to 20 J / cm ² , and more preferably 1 to 20 J / cm ² .
The liquid crystal display element is a person who controls a pretilt angle of a liquid crystal molecule through a PSA (Polymer Sustained Alignment) method. In the PSA method, a small amount of a photopolymerizable compound, such as a photopolymerizable monomer, is mixed into a liquid crystal material to form a liquid crystal cell, and the photopolymerizable compound is irradiated with ultraviolet rays while the liquid crystal layer is applied with a specific voltage. The resulting polymer controls the pretilt angle of the liquid crystal molecules. After the voltage is removed, the alignment state of the liquid crystal molecules when the polymer is generated is still memorized. Therefore, the pretilt angle of the liquid crystal molecules can be adjusted by controlling the electric field or the like formed in the liquid crystal layer. In addition, in the PSA method, rubbing treatment is not necessary, so it is suitable for forming a vertical alignment type liquid crystal layer in which it is difficult to control the pretilt angle using rubbing treatment.

The liquid crystal display element of the present invention uses the above-mentioned method to prepare a liquid crystal alignment agent of the present invention with a substrate with a liquid crystal alignment film, and then prepares a liquid crystal cell as a liquid crystal display element by a known method.
A method for manufacturing a liquid crystal cell, for example, preparing a pair of substrates having a liquid crystal alignment film, and spreading a spacer on the liquid crystal alignment film of a single-sided substrate, and bonding the liquid crystal alignment film to the other side, The method of injecting and sealing the liquid crystal under reduced pressure on the substrate, or the method of attaching the substrate and sealing after dropping liquid crystal on the liquid crystal alignment film surface of the spacer.

The liquid crystal may contain a polymerizable compound polymerized by ultraviolet irradiation or heat treatment as described above. Polymerizable compound, a compound having one or more polymerizable unsaturated groups such as an acrylate group or a methacrylate group in the molecule, for example, polymerizable properties represented by the following formulae (M-1) to (M-3) Compounds etc.

In this case, the content of the polymerizable compound is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass based on 100 parts by mass of the liquid crystal component. When the amount of the polymerizable compound is less than 0.01 parts by mass, the polymerizable compound cannot be polymerized and the alignment of the liquid crystal cannot be controlled. When the amount of the polymerizable compound is more than 10 parts by mass, the amount of unreacted polymerizable compound is too much, which may cause the afterimage characteristics of the liquid crystal display element to decrease. . Generally, after the liquid crystal cell is manufactured, an AC / DC voltage is applied to the liquid crystal cell, and heat treatment or irradiation with ultraviolet rays is performed to polymerize the polymerizable compound. In this way, the alignment of the liquid crystal molecules can be controlled.

The liquid crystal alignment agent of the present invention is also applicable to a polymer having a liquid crystal layer between a pair of substrates provided with electrodes, and a polymer containing a polymerizable polymerizable material through at least one of an active energy ray and a heat treatment. The liquid crystal alignment film based on the polar group is a liquid crystal display element prepared by applying a voltage between the electrodes, that is, it is also suitable for the SC-PVA mode. Among them, the active energy rays are preferably ultraviolet rays. Ultraviolet rays are also suitable in the form of ultraviolet rays including the PSA method described above. When polymerization is performed by heat treatment, the heating temperature is 40 to 120 ° C, and preferably 60 to 80 ° C. Moreover, you may perform ultraviolet irradiation and heat processing simultaneously.

In order to obtain a liquid crystal alignment film containing a polymerizable group polymerized through one of active energy rays and heat treatment, a method of adding a compound containing the polymerizable group to a liquid crystal alignment agent, or A method of using a polymer component containing a polymerizable group, and the like. Specific examples of the polymer containing a polymerizable group include a polymer obtained by using the above-mentioned diamine having a function of polymerizing upon irradiation with light.

[Example]

Examples will be listed below to describe the present invention in more detail, but the present invention is not limited to these contents. The abbreviation of the compound and the method of property evaluation are as follows.

Boc ₂ O: di-tert-butyl dicarbonate, DMAP: dimethylaminopyridine
NMP: N-methyl-2-pyrrolidone, BCS: butyl cellosolve

(Tetracarboxylic dianhydride)
BODA: Bicyclic [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride (compound represented by the following formula "BODA")
CBDA: 1,2,3,4-cyclobutane tetracarboxylic dianhydride (compound represented by the following formula "CBDA")
TCA: 2,3,5-tricarboxycyclopentylacetic dianhydride (compound represented by the following formula "TCA")
PMDA: pyromellitic anhydride (compound represented by the following formula "PMDA")

(Specific diamine)
DA-1: Compound represented by the following formula "DA-1"
DA-2: Compound represented by the following formula "DA-2"

(Diamine with specific side chain structure)
DA-3: 1,3-diamino-4- [4- (trans-4-n-heptylcyclohexyl) phenoxy] benzene
DA-4: a diamine having a specific side chain structure represented by the following formula
DA-5: a diamine having a specific side chain structure represented by the following formula
DA-6: a diamine having a specific side chain structure represented by the following formula

(Other diamines)
Diamines of DA-7 to DA-10 represented by the following structures

(additive)
3AMP: 3-pyridylamine

<Number average molecular weight (Mn) and weight average molecular weight (Mw) of the polymer>
A normal-temperature gel permeation chromatography device (GPC, manufactured by Apex Scientific Corporation, SSC-7200) and a column made by Shodex (KD-803, KD-805) were used. The eluent was N, N'-dimethylformamidine. Ammonium (lithium bromide-water compound (LiBr · H ₂ O) contains 30mmol / L, phosphoric acid · anhydrous crystal (o-phosphoric acid) contains 30mmol / L, tetrahydrofuran contains 10ml / L), flow rate is 1.0ml / Minutes, column temperature is 50 ° C, TSK standard polyethylene oxide (molecular weight of about 9000,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation and polyethylene glycol (molecular weight of about 12,000, 4,000, 1,000) As a standard solution.

＜ Imidization rate ＞
20 mg of polyfluorene imide powder was added to an NMR sample tube (NMR sample standard tube manufactured by Kusano Science Corporation) 5 and 1.0 ml of a dihydrogen dimethylsulfonate (DMSO-d ₆ , 0.05% TMS mixture) was added. The sound waves completely dissolve it. This solution was used to measure a proton NMR at 500 MHz using an NMR measuring device (JNW-ECA500) manufactured by Japan Electronic Data Corporation. The hydrazone imidization rate is determined by using protons generated from structures that have not changed before and after hydrazone as the reference protons. The peak value of the protons is used to compare with the sulfamic acid that appears around 9.5 to 10.0 ppm The integral value of the proton peak generated by the NH group is obtained by the following calculation formula.

(Where x is the integrated value of the proton peak generated by the NH group of amidine, y is the integrated value of the peak value of the reference proton, and α is a polyamidate (amidation ratio of 0%), relative to 醯Proton of one NH group of amine acid, the proportion of the number of reference protons).

[Synthesis Example 1]: Synthesis of Compound 1

Under a nitrogen atmosphere, dimethylformamide (1100g), 2- (2-aminoethylamino) -ethanol (45.3g), 4-fluoronitrobenzene (126g), potassium carbonate (145g), It was added to a 4-necked flask and stirred at room temperature for 168 hours. Thereafter, the filtrate obtained after removing potassium carbonate by filtration was poured into a dilute hydrochloric acid aqueous solution obtained by diluting 50 ml of concentrated hydrochloric acid with 2000 ml of water, and the precipitated compound 1 was filtered to obtain a crude product. The crude product was suspended in 750 ml of ethanol, stirred under reflux for 2 hours, cooled to room temperature, and then filtered, and the filter cake was washed twice with 100 ml of ethanol. The obtained crystals were suspended in 1250 ml of tetrahydrofuran, stirred at 60 ° C. for 24 hours, cooled to room temperature, and then filtered. The obtained filter cake was washed twice with 100 ml of tetrahydrofuran to obtain 62.3 g of a dried compound 16 (yield 41.4%).

[Synthesis Example 2]: Synthesis of Compound 2

In a nitrogen atmosphere, add compound 1 (20.4 g), DMAP (0.362 g), and NMP (170 g) to a 4-necked flask, and then dilute Boc ₂ O (30.1 g) with 30 ml of NMP at room temperature. Drip into it. After stirring at room temperature for 17 hours, 250 ml of water was added, and the precipitated compound 2 was filtered. The obtained filter cake was washed 4 times with 100 ml of water to obtain 30.1 g of the dried compound 2 (yield: 93.6%).

[Synthesis Example 3] Synthesis of Compound (DA-1)

Under a nitrogen atmosphere, compound 2 (30.1 g), 5% palladium-carbon powder, 50% hydrate (3.01 g), and tetrahydrofuran (240 g) were added to a 4-necked flask, and replaced with a hydrogen atmosphere at room temperature and normal pressure. Stir for 120 hours. After the reaction was completed, palladium carbon was filtered using a 0.45 μm PTFE membrane filter, and the obtained filtrate was concentrated and dried to obtain 26.5 g of DA-1 (yield 99.0%).

The structure of the compound (DA-1) was confirmed to have the following pattern data by ¹ H-NMR measurement. Furthermore, NMR measurement was performed using JNW-ECA500 manufactured by Japan Electronic Data Corporation. ¹ H-NMR (DMSO-d ₆ ): δ = 6.78-6.76 (br, 2H), 6.46 (t, 4H), 6.41 (t, 2H), 5.01 (s, 2H), 4.37 (s, 2H), 3.94 (t, 2H), 3.45 (t, 2H), 3.30-3.19 (br, 4H), 1.40-1.35 (br, 18H).

[Synthesis Example 1]
BODA (3.38g, 13.5mmol), DA-1 (6.13g, 12.6mmol)
DA-3 (2.06g, 5.4mmol), dissolved in NMP (46.2g), and reacted at 80 ° C for 5 hours, then added CBDA (0.830g, 4.23mmol) and NMP (3.11g), and then at 40 ° C The mixture was reacted for 11 hours to prepare a polyamic acid solution.
NMP was added to the polyamidic acid solution (40g) and diluted to 6.5% by mass, and then acetic anhydride (5.9g) and pyridine (1.8g) were added as the phosphonium imidization catalyst, and reacted at 100 ° C for 3 hours. . This reaction solution was poured into methanol (560 ml), and the obtained precipitate was filtered off. This precipitate was washed with methanol, and dried under reduced pressure at 100 ° C to obtain a polyfluorene imine powder (A). The polyimide has a fluorene imidation ratio of 72%, Mn of 17,000, and Mw of 132,000.

[Synthetic Comparative Example 1]
Except that the diamine DA-1 used was replaced with DA-2, the polyimide powder (B) was prepared by the same method as in Synthesis Example 1. The polyimide has a fluorene imidation ratio of 74%, Mn of 14,000, and Mw of 56,000.

[Synthesis Example 2] to [Synthesis Comparative Example 5]
According to the same implementation method as in Synthesis Example 1, various polytetracarboxylic acid components and diamine components were used to prepare a polyfluorinated acid solution and a polyfluorinated imine powder. Table 1 shows the composition of the synthesized polymer.

In the numerical values in Table 1, the tetracarboxylic dianhydride represents the use ratio (mole%) with respect to the total amount of the tetracarboxylic dianhydride used in the reaction, and the diamine represents the ratio with respect to the diamine component used in the reaction. Use ratio (mol%).

＜ Manufacturing and evaluation of liquid crystal alignment agent ＞
[Example 1]
NMP (44.0 g) was added to the polyimide powder (A) (6.0 g) obtained in the above-mentioned manner, and the mixture was stirred at 80 ° C for 17 hours to be dissolved. To this solution, a 6 mass% NMP diluted solution (1.0 g), NMP (9.0 g), and BCS (40.0 g) of 3AMP were added and stirred at room temperature for 5 hours to obtain a liquid crystal alignment agent (A1).

(Manufacture of PSA type liquid crystal display element)
Using the liquid crystal alignment agent (A1) prepared as described above, a liquid crystal display element was manufactured in the order shown below. The liquid crystal alignment agent (A1) was spin-coated on an ITO surface of an ITO electrode substrate having ITO electrode patterns with a pixel size of 100 μm × 300 μm and a line / space of 5 μm each, and dried on a heating plate at 80 ° C. After 90 seconds, a 230 ° C infrared heating furnace was used for sintering for 20 minutes to form a liquid crystal alignment film with a thickness of 100 nm.
In addition, a severe condition for evaluating the vertical alignment of the liquid crystal alignment film is to sinter it in an infrared heating furnace at 230 ° C. for 60 minutes to form a liquid crystal alignment film with a thickness of 100 nm.

Using two of the above substrates, a particle spacer having a pore size of 4 μm was spread on the liquid crystal alignment film of one of the substrates, and then a sealant (solvent type thermosetting epoxy resin) was printed thereon. Next, another substrate is bonded to the previous substrate such that the side of the liquid crystal alignment film is formed facing inward, and then the sealant is hardened to obtain an empty cell. A liquid crystal cell was prepared by injecting the negative cell MLC-3023 (trade name, manufactured by Meike Corporation) containing a polymerizable compound for PSA into the empty cell by a reduced pressure injection method.

Subsequently, under a state in which a DC voltage of 15 V was applied to the liquid crystal cell, a UV of 10 J / cm ² (also referred to as a primary PSA treatment) was irradiated from the outside of the liquid crystal cell through a 325 nm band-pass filter. The UV illuminance was measured using UV-MO3A manufactured by ORC Corporation. Thereafter, for the purpose of passivation of the unreacted polymerizable compound remaining in the liquid crystal cell, a UV-FL irradiation device manufactured by Toshiba Optical Technology Co., Ltd. was irradiated with UV (UV lamp: 30 minutes) without applying a voltage. FLR40SUV32 / A-1) (also called secondary PSA treatment), and a liquid crystal display element is obtained.

(1) Evaluation of voltage holding ratio Using the liquid crystal display device prepared above, in a hot air circulation oven at 60 ° C., after applying an application time of 60 microseconds at a voltage of 1 V, the voltage holding ratio after 1667 ms was removed from the measurement . This value is set as a voltage holding ratio (VHR _BF ). As the measurement device, VHR-1 manufactured by Toyo Technology Co., Ltd. was used. The higher the VHR _BF , the better.

(2) Evaluation of high temperature and high humidity resistance After the liquid crystal display device was placed in a constant temperature and humidity device (PR-2KP manufactured by Espec Corporation) at a temperature of 85 ° C and a humidity of 85%, the voltage retention ratio was implemented. Determination. This value is set as a voltage holding ratio (VHR _AF ). The decrease amount ΔVHR (%) of the voltage holding ratio is obtained from the following calculation formula, and is used as an evaluation value of high temperature and high humidity resistance. The lower the ΔVHR, the better. The results are shown in Table 1.

(3) Evaluation of adhesion The samples for adhesion evaluation were prepared in the following order. The liquid crystal alignment agent was applied on a 30 mm × 40 mm ITO substrate using a spin coater. After drying on a hot plate at 80 ° C for 90 seconds, it was sintered in an infrared heating furnace at 230 ° C for 20 minutes to form a coating film with a thickness of 100 nm. Two substrates obtained in this manner were prepared, and a particle spacer having a pore size of 4 μm was coated on the liquid crystal alignment film surface of one of the substrates, and then a sealant (UV-curable type) was dropped. Next, another substrate is bonded to the previous substrate so that the side of the liquid crystal alignment film is formed facing inward, and then the sealant is hardened to obtain an empty cell. At this time, the dripping amount of the sealant was adjusted so that the diameter of the sealant after bonding was 3 mm. The two bonded substrates were fixed with a jig, and then subjected to a heat curing treatment at 120 ° C for one hour to obtain a sample for evaluating adhesion.
Thereafter, a sample precision universal testing machine AGS-X 500N made by Shimadzu Corporation was used for this sample substrate, and the front end portion of the upper and lower substrates was fixed, and then a press-in test was performed from above the center portion of the substrate to measure the pressure during peeling. (N). The vernier caliper was used to measure the diameter of the peeling mark remaining on the substrate, and the value (the peeling strength per unit length side) obtained by dividing the diameter of the peeling mark under pressure (N) at the time of peeling was used as the evaluation of adhesion. The results obtained are shown in Table 2.

(4) Evaluation of vertical alignment The LCD analyzer (LCA-LUV42A, manufactured by Mingling Technology Co., Ltd.) was used to measure the pretilt angle of the liquid crystal display element obtained by the above method. The difference between the pre-tilt angle of the normal sintering condition (20 min) and the severe condition (60 min) was calculated (normal condition-severe condition = Δ pre-tilt angle). The smaller the Δpretilt angle, the better the vertical alignment of the liquid crystal alignment film. The results are shown in Table 2.

[Comparative Example 1]
The polyfluorene imide powder (B) obtained according to the above method was subjected to the same method as in Example 1 to prepare a liquid crystal alignment agent (B1).
In addition, using the obtained liquid crystal alignment agent (B1), evaluations (1) to (4) were performed in the same manner as in Example 1.

[Example 2] to [Comparative Example 4]
According to the same implementation method as in Example 1, liquid crystal alignment agents (C1) to (I1) were prepared.
The liquid crystal alignment agent (E1) (3.0 g) was mixed with the liquid crystal alignment agent (I1) (7.0 g), and after stirring for 3 hours, a liquid crystal alignment agent (E2) was obtained.

From the above evaluation results, it was confirmed that the sample containing the diamine compound of the present invention has good sealing and adhesion, and has excellent high temperature and high humidity resistance, pretilt angle stability, and the like.
On the other hand, when DA-2 liquid crystal alignment agent was used, it was found that it has excellent high temperature and high humidity resistance, but there is still room for improvement in stability of the pretilt angle (Comparative Example 1).
In general, when the purpose of improving the stability of the tilt angle is to introduce a side chain structure with a large ring structure, but a side chain structure with a high hydrophobicity may reduce the adhesion to the sealant or the glass substrate. Tendency (Comparative Example 2).
In addition, although the seal adhesion can be improved through the material design of polyamic acid, etc., conventional polyamino acids show an unstable state when they are stimulated by humidity or heat. High temperature and high humidity are not good (Comparative Example 4).

[Industrial availability]

The liquid crystal display element using the liquid crystal alignment film obtained by the liquid crystal alignment agent of the present invention is suitable for use in a liquid crystal display for display purposes. In addition, it is also suitable for a wide range of dimming windows or light curtains that control light transmission and block light range.
In addition, the entire contents of the specification, patent application scope, drawings, and abstract of Japanese Patent Application No. 2018-068720 filed on March 30, 2018 are incorporated by reference, and are provided as the disclosure of the present specification.

Claims (11)

A liquid crystal alignment agent characterized by containing a polymer (P) having a partial structure represented by the following formula (I-1) or formula (I-2); (A represents a (n + 1) -valent hydrocarbon group having 1 to 18 carbon atoms, or a carbon-carbon bond of a hydrocarbon group having a -O-, -COO-, -CO-, or -NHCO- group; S represents a single Bond or hydrocarbon group of 1 to 4 carbons; P ₁ represents a hydroxyl group protected by a thermally dissociable group; n is an integer of 1 to 5; m is an integer of 1 to 2; when m is 1, R ₁ represents a carbon number of 1 to For a hydrocarbon group of 4 and m is 2, R ₁ represents a hydrogen atom. * Represents a bonding bond to a hydrocarbon group). The liquid crystal alignment agent according to claim 1, wherein the polymer (P) further has an amine group protected by a thermally dissociable group. The liquid crystal alignment agent according to claim 1 or 2, wherein the polymer (P) is made of polyimide precursor and polyimide obtained by polyimide imidization of the polyimide precursor. Group of at least one selected polymer. The liquid crystal alignment agent according to any one of claims 1 to 3, wherein the foregoing polyfluorene imide precursor has a partial structure represented by the foregoing formula (I-1) or (I-2), and has a A polymer prepared by thermally dissociating an amine-based diamine. The liquid crystal alignment agent according to claim 4, wherein the diamine is at least one selected from the group consisting of the following formulae (II-1) to (II-3); (In the formula, L and M represent a divalent organic group, Q represents a trivalent organic group, and n is an integer of 0 to 2. P represents a structure represented by the aforementioned formula (I-1) or formula (I-2). ; P ₂ represents an amine group protected by a thermally dissociable group). The liquid crystal alignment agent according to claim 5, wherein in the formulae (II-1) to (II-3), L and M represent an alkylene group having 1 to 11 carbon atoms, a divalent aliphatic ring structure, or Divalent aromatic ring structure; when any -CH ₂ -in the alkylene group is not a combination adjacent to each other, it can be replaced by -O-, -COO-, or -Si-O-Si-, or Substituted by the ring structure shown; R ₂ represents a hydrocarbon group of carbon atoms 1 to 5; . The liquid crystal alignment agent according to any one of claims 4 to 6, wherein the polyfluorene imide precursor is one having a side chain structure selected from the group represented by the following formulas [S1] to [S3]. Polymers obtained from diamines; (X ¹ and X ² each independently represent a single bond,-(CH ₂ ) _a- (a is an integer from 1 to 15), -CONH-, -NHCO-, -CON (CH ₃ )-, -NH-,- O -, - COO-, -OCO- or _{- ((CH 2) a1 -A} 1) m1 -; wherein a plurality of a1 each independently represents an integer of 1 to 15, a plurality of A ₁ each independently represents an oxygen atom or a - COO-; m ₁ is 1 to 2; G ¹ and G ² each independently represent a bivalent aromatic group having 6 to 12 carbon atoms or a divalent alicyclic group having 3 to 8 carbon atoms Cyclic group; any hydrogen atom on the cyclic group may be 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 1 carbon atom At least one selected from the group consisting of a fluorine-containing alkoxy group or a fluorine atom of 3 to 3; m and n each independently represent an integer of 0 to 3, and the total of m and n is 1 to 4; R ¹ represents (C1-C20 alkyl group, C1-C20 alkoxy group, or C2-C20 alkoxyalkyl group; any hydrogen forming R ¹ may be replaced by fluorine) (X ³ represents a single bond, -CONH-, -NHCO-, -CON (CH ₃ )-, -NH-, -O-, -CH ₂ O-, -COO- or -OCO-; R ² represents a carbon number 1 to 20 alkyl groups or 2 to 20 alkoxyalkyl groups; any hydrogen that forms R ² may be replaced by fluorine) (X ⁴ represents -CONH-, -NHCO-, -O-, -COO-, or -OCO-; R ³ represents a structure having a cholesterol skeleton). The liquid crystal alignment agent according to any one of claims 1 to 7, wherein the thermally dissociable group is a group which can be substituted with a hydrogen atom at a temperature of 150 to 300 ° C. The liquid crystal alignment agent according to any one of claims 1 to 8, wherein the thermally dissociable group is a t-butoxycarbonyl group. A liquid crystal alignment film, comprising a liquid crystal alignment agent according to any one of claims 1 to 9. A liquid crystal display element comprising the liquid crystal alignment film of claim 10.