WO2014126102A1

WO2014126102A1 - Production method for liquid-crystal alignment film, liquid-crystal alignment film, liquid-crystal display element, and liquid-crystal alignment agent

Info

Publication number: WO2014126102A1
Application number: PCT/JP2014/053188
Authority: WO
Inventors: 幸司巴; 奈穂菊池; 雅章片山; 徳俊三木
Original assignee: 日産化学工業株式会社
Priority date: 2013-02-13
Filing date: 2014-02-12
Publication date: 2014-08-21
Also published as: TW201446839A; JPWO2014126102A1; TWI628202B; JP6361887B2; CN105122128B; CN105122128A; KR102172134B1; KR20150119199A; JP6361887B6

Abstract

A liquid-crystal alignment agent is applied to a substrate and subsequently baked to obtain a liquid-crystal alignment film having an imidization ratio of 50-70%. The liquid-crystal alignment agent includes: a polyimide precursor having repeating units represent by formula [1]; and at least one polymer selected from polyimides which have repeating units represented by formula [1], and which have an imidization ratio of less than 50% (in formula [1]: A₁ represents a divalent organic group; A₂ represents a divalent organic group; and C₁ and C₂ each represent hydrogen or a C1-3 alkyl group, and may be the same as or different to each other).

Description

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

The present invention relates to a method for producing a liquid crystal alignment film, a liquid crystal alignment film, a liquid crystal display element using the liquid crystal alignment film, and a liquid crystal alignment agent used when producing the liquid crystal alignment film.

Liquid crystal display elements used for liquid crystal televisions and liquid crystal displays are now widely used as thin and light display devices. In the liquid crystal display element, the liquid crystal alignment film plays a role of aligning the liquid crystal in a certain direction. Currently, the main liquid crystal alignment films used industrially are a polyimide precursor polyamic acid (also called polyamic acid), a polyamic acid ester, and a liquid crystal aligning agent composed of a polyimide solution applied to a substrate and baked. It is formed by doing.

In the formation of such a liquid crystal alignment film, if the baking temperature is high, there arises a problem that a substrate having low heat resistance cannot be used. Therefore, it is desirable to lower the baking temperature. As a technique capable of forming a liquid crystal alignment film at a low baking temperature, for example, a liquid crystal alignment film containing a polymer containing a polyurea-based repeating structural unit and a polyimide-based repeating structural unit in the same molecule is disclosed (patent) Reference 1).

Japanese Patent Laid-Open No. 08-220542

However, the liquid crystal alignment film of Patent Document 1 has a problem of high residual DC. Further, the liquid crystal alignment film is also required to have a high voltage holding ratio as another electrical characteristic.

An object of the present invention is to solve the above-described problems of the prior art, and a method for producing a liquid crystal alignment film, which can form a liquid crystal alignment film having a low residual DC and a high voltage holding ratio by firing at a low temperature, and a liquid crystal alignment It aims at providing a film | membrane, a liquid crystal display element, and a liquid crystal aligning agent.

This invention which solves the said subject makes the following a summary.
1. Contains at least one polymer selected from a polyimide precursor having a repeating unit represented by the following formula [1] and a polyimide having a repeating unit represented by the following formula [1] and having an imidation ratio of less than 50% A method for producing a liquid crystal alignment film, characterized in that a liquid crystal alignment film having an imidization ratio of 50 to 70% is obtained by applying a liquid crystal aligning agent to the substrate and then baking the liquid crystal aligning agent.

(In Formula [1], A ₁ is a divalent organic group, A ₂ is a divalent organic group, C ₁ and C ₂ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, It can be the same or different.)

2. The firing is performed at 210 ° C. or lower. The manufacturing method of the liquid crystal aligning film as described in any one of.

3. The polymer has a side chain represented by the following formula [2]. Or 2. The manufacturing method of the liquid crystal aligning film as described in any one of.

(In the formula [2], Y ₁ is a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 15), —O—, —CH ₂ O—, —COO— or —OCO—. Y ₂ is a single bond or — (CH ₂ ) _b — (b is an integer of 1 to 15), Y ₃ is a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 15) ), —O—, —CH ₂ O—, —COO— or —OCO—, wherein Y ₄ is a carbon having a divalent cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, or a steroid skeleton A divalent organic group having 17 to 51, wherein any hydrogen atom on the cyclic group contains an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, or fluorine having 1 to 3 carbon atoms alkyl group may be substituted with a fluorine-containing alkoxyl group or a fluorine atom having 1 to 3 carbon atoms, Y ₅ Baie A divalent cyclic group selected from a zen ring, a cyclohexane ring and a heterocyclic ring, wherein any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, carbon The fluorine-containing alkyl group having 1 to 3 carbon atoms, the fluorine-containing alkoxyl group having 1 to 3 carbon atoms or the fluorine atom may be substituted, n is an integer of 0 to 4, and Y ₆ has 1 to 18 carbon atoms. An alkyl group, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 18 carbon atoms.)

4). The polymer is obtained by reacting the following components (a), (b) and (c): ~ 3. The manufacturing method of the liquid crystal aligning film as described in any one of these.
(A) Component: Compound containing two isocyanate groups in the molecule (b) Component: Compound containing two primary or secondary amino groups in the molecule (c) Component: Tetracarboxylic acid derivative

5. 3. The component (b) is a compound having a side chain represented by the formula [2]. The manufacturing method of the liquid crystal aligning film as described in any one of.

6). 3. The component (b) is a compound represented by the following formula [2a]. The manufacturing method of the liquid crystal aligning film as described in any one of.

(In Formula [2a], Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ , Y ₆ , and n are Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ , Y ₆ in Formula [2]. , N, m is an integer of 1 to 4, and — (Y ₁ —Y ₂ —Y ₃ —Y ₄ — (Y ₅ ) _n —Y ₆ ) _m is a substituent Y ₁ —Y ₂ —. Y ₃ —Y ₄ — (Y ₅ ) _n —Y ₆ represents m, and when m is 2 or more, each substituent may be the same or different.)

7). 3. The component (c) is a tetracarboxylic dianhydride represented by the following formula [3]. ~ 6. The manufacturing method of the liquid crystal aligning film as described in any one of these.

(In the formula [3], Z ₁ is a structure represented by the following formulas [3a] to [3j]).

(In the formula [3a], Z ₂ to Z ₅ are a hydrogen atom, a methyl group, a chlorine atom or a benzene ring, and may be the same or different. In the formula [3g], Z ₆ and Z ₇ Are hydrogen atoms or methyl groups, which may be the same or different.

8). 1. The polymer in the liquid crystal aligning agent is 0.1 to 30% by mass. ~ 7. The manufacturing method of the liquid crystal aligning film as described in any one of these.

9. The coating is performed by an ink jet method. ~ 8. The manufacturing method of the liquid crystal aligning film as described in any one of these.

10. 1. ~ 9. A liquid crystal alignment film manufactured by the method for manufacturing a liquid crystal alignment film according to any one of the above.

11. A liquid crystal alignment film comprising a polyimide having a repeating unit represented by the following formula [1] and having an imidization ratio of 50 to 70%.

12 A liquid crystal composition comprising a liquid crystal layer between a pair of substrates provided with electrodes and comprising a polymerizable compound that is polymerized by at least one of active energy rays and heat is disposed between the pair of substrates, and the electrodes 9. It is used for a liquid crystal display device manufactured through a step of polymerizing the polymerizable compound while applying a voltage therebetween. Or 11. A liquid crystal alignment film as described in 1.

13. A liquid crystal layer between a pair of substrates provided with electrodes, and a liquid crystal alignment film containing a polymerizable group that is polymerized by at least one of active energy rays and heat between the pair of substrates; 9. It is used for a liquid crystal display device manufactured through a step of polymerizing the polymerizable group while applying a voltage therebetween. Or 11. A liquid crystal alignment film as described in 1.

14 10. ~ 13. A liquid crystal display element comprising the liquid crystal alignment film according to any one of the above.

15. A liquid crystal aligning agent comprising a polyimide precursor having a repeating unit represented by the following formula [1].

According to the present invention, there is provided a liquid crystal aligning agent containing a polyimide precursor having a repeating unit represented by the formula [1] or a polyimide having a repeating unit represented by the formula [1] and having an imidization ratio of less than 50%. A liquid crystal alignment film having a low residual DC and a high voltage holding ratio can be obtained by using, coating and baking to form a liquid crystal alignment film having an imidization ratio of 50 to 70%. Further, since the baking temperature can be as low as 210 ° C. or less, for example, a plastic substrate having a relatively low heat resistance can be used as the substrate, and the color filter of the liquid crystal display element accompanying the baking at a high temperature. It is possible to suppress the deterioration of the color characteristics and to reduce the energy cost in manufacturing the liquid crystal display element.

The present invention is described in detail below.
The method for producing a liquid crystal alignment film of the present invention includes a polyimide precursor having a repeating unit represented by the formula [1] and a polyimide having a repeating unit represented by the formula [1] and an imidation ratio of less than 50%. A liquid crystal alignment film having an imidation ratio of 50 to 70% is obtained by applying a liquid crystal aligning agent containing at least one polymer selected from the above to a substrate and then baking it.

The liquid crystal aligning agent used for manufacture of the liquid crystal aligning film of this invention has a polyimide precursor which has a repeating unit shown by the said Formula [1], a repeating unit shown by the said Formula [1], and an imidation rate Contains less than 50% polyimide. Of course, even if it contains both a polyimide precursor having a repeating unit represented by the above formula [1] and a polyimide having a repeating unit represented by the above formula [1] and having an imidization ratio of less than 50%. Good. In addition, it contains a polyimide precursor having a plurality of repeating units represented by the above formula [1] and a polyimide having a plurality of repeating units represented by the above formula [1] and having an imidization ratio of less than 50%. It may be. The polyimide precursor is a polyamic acid or a polyamic acid ester.

A polyimide precursor having a repeating unit represented by the above formula [1] or a polyimide having a repeating unit represented by the above formula [1] and an imidization ratio of less than 50% (hereinafter referred to as a repeating unit represented by the formula [1] It is preferable that the polymer having a side chain represented by the above formula [2]. When it has a side chain represented by the above formula [2], a liquid crystal alignment film capable of vertically aligning liquid crystals can be produced. For example, when the repeating unit represented by the formula [1] has a side chain represented by the formula [2], A ₁ and A ₂ have a structure represented by the formula [2]. Further, in detail, a polyimide precursor or a repeating unit of polyimide described later may have a side chain represented by the above formula [2].

In the formula [1], Y ₁ represents a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 15), —O—, —CH ₂ O—, —COO— or —OCO—. . Among these, from the viewpoint of availability of raw materials and ease of synthesis, a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 15), —O—, —CH ₂ O— or —COO. -Is preferred. More preferred is a single bond, — (CH ₂ ) _a — (a is an integer of 1 to 10), —O—, —CH ₂ O— or —COO—.

In the formula [1], Y ₂ represents a single bond or — (CH ₂ ) _b — (b is an integer of 1 to 15). Among these, a single bond or — (CH ₂ ) _b — (b is an integer of 1 to 10) is preferable.

In the formula [1], Y ₃ represents a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 15), —O—, —CH ₂ O—, —COO— or —OCO—. . Of these, a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 15), —O—, —CH ₂ O— or —COO— is preferable from the viewpoint of ease of synthesis. More preferred is a single bond, — (CH ₂ ) _c — (c is an integer of 1 to 10), —O—, —CH ₂ O— or —COO—.

In the formula [1], Y ₄ represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, or a divalent organic group having 17 to 51 carbon atoms and having a steroid skeleton, Are substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. It may be. Among these, an organic group having 17 to 51 carbon atoms having a benzene ring, a cyclohexane ring or a steroid skeleton is preferable from the viewpoint of ease of synthesis.

In the formula [1], Y ₅ represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, and any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, carbon It may be substituted with an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. Of these, a benzene ring or a cyclohexane ring is preferable.

In the formula [1], n is an integer of 0 to 4. Among these, 0 to 3 are preferable from the viewpoint of availability of raw materials and ease of synthesis. More preferred is 0-2.

In the formula [1], Y ₆ is an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 18 carbon atoms. . Of these, an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 10 carbon atoms is preferable. More preferably, it is an alkyl group having 1 to 12 carbon atoms or an alkoxyl group having 1 to 12 carbon atoms. Particularly preferred is an alkyl group having 1 to 9 carbon atoms or an alkoxyl group having 1 to 9 carbon atoms.

In the formula [1], preferred combinations of Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ , Y ₆ and n are listed in Items 13 to 34 of International Publication No. WO2011 / 132751 (published 2011.10.27). Examples thereof include the same combinations as (2-1) to (2-629) listed in Tables 6 to 47 in the section. In each table of the International Publication, Y ₁ to Y ₆ in the present invention are shown as Y ₁ to Y ₆ , but Y ₁ to Y ₆ are read as Y ₁ to Y ₆ .

The polyimide precursor having a repeating unit represented by the above formula [1] includes, for example, a component (a) which is a compound containing two isocyanate groups in the molecule, and a primary or secondary amino group in the molecule. It can manufacture by making (b) component which is a compound containing two, and (c) component which is a tetracarboxylic acid derivative react.

The component (a) is a compound represented by O═C═NA ₁ —N═C═O (A ₁ is the same as A ₁ in the formula [1]). Examples of A ₁ include a substituent composed of a divalent benzene ring, an alkylene group, an aliphatic ring, or a combination thereof, in which a hydrogen atom may be substituted with an alkyl group having 1 to 5 carbon atoms. Specific examples of the component (a) include aromatic diisocyanates such as o-phenylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, toluene diisocyanates (for example, tolylene 2,4-diisocyanate), 1,4-diisocyanate. Acid-2-methoxybenzene, 2,5-diisocyanate xylenes, 2,2′-bis (phenyl diisocyanate) propane, 4,4′-diisocyanate diphenylmethane, 4,4′-diisocyanate diphenyl ether, 4 , 4′-diisocyanate diphenylsulfone, 3,3′-diisocyanate diphenylsulfone, 2,2′-diisocyanate benzophenone, etc., as the aliphatic diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, tetramethyl Le ethylene diisocyanate. Of these, 2,4-diisocyanate tolylene is preferable from the viewpoints of availability, polymerization reactivity, and voltage holding ratio.

The component (b) is a compound represented by the following formula [b].

(Wherein _{_{[b], C 1, C}} 2, A 2 is the same as _C _1, _C _{_2, A} 2 in the formula [1])
A ₂ includes a divalent organic group derived from the component (b) compound. Specific examples of the component (b) include compounds represented by the above formula [2a].

The bonding position of the _two amino groups (—NH ₂ ) in the above formula [2a] is not limited. Specifically, a few positions on the benzene ring with respect to the side chain linking group (— (Y ₁ —Y ₂ —Y ₃ —Y ₄ — (Y ₅ ) _n —Y ₆ ) _m ), 2,4 positions, 2,5 positions, 2,6 positions, 3,4 positions or 3,5 positions. Among these, from the viewpoint of the reactivity when synthesizing the polymer having the repeating unit represented by the formula [1], the positions 2, 4, 2, 5, or 3, 5 are preferable. Considering the ease in synthesizing the compound represented by the formula [2a], the positions 2, 4 or 2, 5 are more preferable.

More specifically, the formula [2a] is a structure represented by the following formula [2b-1] to formula [2b-29].

(In the formulas [2b-19] to [2b-21], R ¹ represents —O—, —OCH ₂ —, —CH ₂ O—, —COOCH ₂ — or —CH ₂ OCO—, and R ² represents An alkyl group having 1 to 18 carbon atoms, an alkoxy group, a fluorine-containing alkyl group or a fluorine-containing alkoxy group).

(In the formulas [2b-22] to [2b-24], R ³ represents —COO—, —OCO—, —COOCH ₂ —, —CH ₂ OCO—, —CH ₂ O—, —OCH ₂ — or — CH ₂ —, and R ⁴ represents an alkyl group having 1 to 18 carbon atoms, an alkoxy group, a fluorine-containing alkyl group or a fluorine-containing alkoxy group).

(In the formulas [2b-25] and [2b-26], R ⁷ represents an alkyl group having 3 to 12 carbon atoms. Note that the cis-trans isomerism of 1,4-cyclohexylene is the trans isomer. preferable).

(In the formulas [2b-27] and [2b-28], R ⁸ represents an alkyl group having 3 to 12 carbon atoms. The cis-trans isomerism of 1,4-cyclohexylene is the trans isomer. preferable).

(In the formula [2b-29], B ⁴ represents an alkyl group having 3 to 18 carbon atoms which may be substituted with a fluorine atom, and B ³ represents a 1,4-cyclohexylene group or a 1,4-phenylene group. B ² represents an oxygen atom or —COO— * (where a bond marked with “*” binds to B ³ ), and B ¹ represents an oxygen atom or —COO— * (where “*” bond marked with the _(CH 2) showing the ^{a 2} binds to). Further, ^{a 1} represents an integer of 2 ~ 10, ^{a 3} represents an integer of 0 or 1).

When the compound represented by the formula [2a] is used, the liquid crystal can be aligned vertically as described above. The compound represented by the formula [2a] is preferably 5 mol% or more and 80 mol% or less of the entire component (b). More preferably, from the viewpoint of liquid crystal alignment, the compound represented by the formula [2a] is 5 mol% or more and 60 mol% of the entire component (b). Most preferably, it is 10 mol% or more and 60 mol% or less of the whole component (b).

As the component (b) other than the compound represented by the formula [2a], m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,6-diaminotoluene, 2,4-diaminophenol, 3,5 -Diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, and diamines having structures represented by the following formulas [2b-30] to [2b-41] A compound can be mentioned.

(In [2b-30] and [2b-31], R ⁵ represents —COO—, —OCO—, —COOCH ₂ —, —CH ₂ OCO—, —CH ₂ O—, —OCH ₂ —, —CH _2- or -O-, and R ⁶ is a fluorine group, a cyano group, a trifluoromethane group, a nitro group, an azo group, a formyl group, an acetyl group, an acetoxy group or a hydroxyl group).

(In the formulas [2b-32] to [2b-35], A ¹ represents an alkyl group having 1 to 22 carbon atoms or a fluorine-containing alkyl group).

The formula [2b-36] has a photoreactive side chain. Such a photoreactive side chain is a portion that causes polymerization upon irradiation with light, and includes, for example, an acryl group, a methacryl group, a lactone group, a maleimide group, a vinyl group, an allyl group, and a styryl group. The side chain which has is mentioned. However, it is not limited to this.

Further, as the component (b) other than the compound represented by the formula [2a], 4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4 , 4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-dicarboxy-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'- Biphenyl, 3,3'-trifluoromethyl-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2'-diaminodiphenylmethane 2,3′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 2,2′-diaminodiphenyl ether, 2,3′-diaminodiphenyl ether, 4, 4'-sulfonyldianiline, 3,3'-sulfonyldianiline, bis (4-aminophenyl) silane, bis (3-aminophenyl) silane, dimethyl-bis (4-aminophenyl) silane, dimethyl-bis (3 -Aminophenyl) silane, 4,4'-thiodianiline, 3,3'-thiodianiline, 4,4'-diaminodiphenylamine, 3,3'-diaminodiphenylamine, 3,4'-diaminodiphenylamine, 2,2'-diamino Diphenylamine, 2,3'-diaminodiph Nylamine, N-methyl (4,4'-diaminodiphenyl) amine, N-methyl (3,4'-diaminodiphenyl) amine, N-methyl (3,4'-diaminodiphenyl) amine, N-methyl (2, 2'-diaminodiphenyl) amine, N-methyl (2,3'-diaminodiphenyl) amine, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 1,4- Diaminonaphthalene, 2,2'-diaminobenzophenone, 2,3'-diaminobenzophenone, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 1,8-diaminonaphthalene, 2,5 -Diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 2,8-di Aminonaphthalene, 1,2-bis (4-aminophenyl) ethane, 1,2-bis (3-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,3-bis (3- Aminophenyl) propane, 1,4-bis (4-aminophenyl) butane, 1,4-bis (3-aminophenyl) butane, bis (3,5-diethyl-4-aminophenyl) methane, 1,4- Bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1, 4-bis (4-aminobenzyl) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4 ′-[1,4-phenylenebis (methylene)] dianiline, 4,4 ′-[1, 3 Phenylenebis (methylene)] dianiline, 3,4 ′-[1,4-phenylenebis (methylene)] dianiline, 3,4 ′-[1,3-phenylenebis (methylene)] dianiline, 3,3 ′-[ 1,4-phenylenebis (methylene)] dianiline, 3,3 ′-[1,3-phenylenebis (methylene)] dianiline, 1,4-phenylenebis [(4-aminophenyl) methanone], 1,4- Phenylenebis [(3-aminophenyl) methanone], 1,3-phenylenebis [(4-aminophenyl) methanone], 1,3-phenylenebis [(3-aminophenyl) methanone], 1,4-phenylenebis (4-aminobenzoate), 1,4-phenylenebis (3-aminobenzoate), 1,3-phenylenebis (4-aminobenzoate), 1 3-phenylenebis (3-aminobenzoate), bis (4-aminophenyl) terephthalate, bis (3-aminophenyl) terephthalate, bis (4-aminophenyl) isophthalate, bis (3-aminophenyl) isophthalate, N , N ′-(1,4-phenylene) bis (4-aminobenzamide), N, N ′-(1,3-phenylene) bis (4-aminobenzamide), N, N ′-(1,4-phenylene) ) Bis (3-aminobenzamide), N, N ′-(1,3-phenylene) bis (3-aminobenzamide), N, N′-bis (4-aminophenyl) terephthalamide, N, N′-bis (3-aminophenyl) terephthalamide, N, N′-bis (4-aminophenyl) isophthalamide, N, N′-bis (3-aminophenyl) ) Isophthalamide, 9,10-bis (4-aminophenyl) anthracene, 4,4′-bis (4-aminophenoxy) diphenylsulfone, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane 2,2′-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2′-bis (4-aminophenyl) hexafluoropropane, 2,2′-bis (3-aminophenyl) Hexafluoropropane, 2,2′-bis (3-amino-4-methylphenyl) hexafluoropropane, 2,2′-bis (4-aminophenyl) propane, 2,2′-bis (3-aminophenyl) Propane, 2,2′-bis (3-amino-4-methylphenyl) propane, 1,3-bis (4-aminophenoxy) propane, 1,3- (3-aminophenoxy) propane, 1,4-bis (4-aminophenoxy) butane, 1,4-bis (3-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1, 5-bis (3-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,6-bis (3-aminophenoxy) hexane, 1,7-bis (4-aminophenoxy) Heptane, 1,7- (3-aminophenoxy) heptane, 1,8-bis (4-aminophenoxy) octane, 1,8-bis (3-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) Nonane, 1,9-bis (3-aminophenoxy) nonane, 1,10-bis (4-aminophenoxy) decane, 1,10-bis (3-aminophenoxy) decane 1,11-bis (4-aminophenoxy) undecane, 1,11-bis (3-aminophenoxy) undecane, 1,12-bis (4-aminophenoxy) dodecane, 1,12-bis (3-aminophenoxy) ) Dodecane, bis (4-aminocyclohexyl) methane, bis (4-amino-3-methylcyclohexyl) methane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6- Examples also include diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane.

Examples of the component (b) include those having an alkyl group, a fluorine-containing alkyl group, an aromatic ring, an aliphatic ring or a heterocyclic ring in the diamine side chain, and those having a macrocyclic substituent composed of these. it can. Specifically, diamine compounds represented by the following formulas [DA1] to [DA13] can be exemplified.

(In the formulas [DA1] to [DA6], A ¹ represents —COO—, —OCO—, —CONH—, —NHCO—, —CH ₂ —, —O—, —CO— or —NH—, A ² represents a linear or branched alkyl group having 1 to 22 carbon atoms or a linear or branched fluorine-containing alkyl group having 1 to 22 carbon atoms).

(In the formula [DA7], p represents an integer of 1 to 10).

Also, as the component (b), diamine compounds represented by the following formulas [DA8] to [DA13] can be used.

(In the formula [DA10], m represents an integer of 0 to 3, and in the formula [DA13], n represents an integer of 1 to 5).

Furthermore, as long as the effects of the present invention are not impaired, diamine compounds represented by the following formulas [DA14] to [DA17] can also be used.

(In the formula [DA14], A ¹ is a single bond, —CH ₂ —, —C ₂ H ₄ —, —C (CH ₃ ) ₂ —, —CF ₂ —, —C (CF ₃ ) ₂ —, —O —, —CO—, —NH—, —N (CH ₃ ) —, —CONH—, —NHCO—, —CH ₂ O—, —OCH ₂ —, —COO—, —OCO—, —CON (CH ₃ ) — Or —N (CH ₃ ) CO—, each of m ¹ and m ² represents an integer of 0 to 4, and m ¹ + m ² represents an integer of 1 to 4, and in the formula [DA15], m ³ and m ⁴ each represent an integer of 1 to 5, and in formula [DA16], A ² represents a linear or branched alkyl group having 1 to 5 carbon atoms, m ⁵ represents an integer of 1 to 5, [DA17] in, ^{A 3} is a single _{_{_{bond, -CH 2 -, - C 2}}} H 4 -, - C (CH 3) 2 -, - CF 2 -, - C (CF 3) 2 _{, -O -, - CO -,} - NH -, - N (CH 3) -, - CONH -, - NHCO -, - CH 2 O -, - OCH 2 -, - COO -, - OCO -, - CON (CH ₃ ) — or —N (CH ₃ ) CO— is represented, and m ⁶ represents an integer of 1 to 4.

In addition, a diamine compound represented by the following formula [DA18] can also be used as long as the effects of the present invention are not impaired.

(In the formula [DA18], A ¹ is —O—, —NH—, —N (CH ₃ ) —, —CONH—, —NHCO—, —CH ₂ O—, —OCO—, —CON (CH ₃ ). A divalent organic group selected from — or —N (CH ₃ ) CO—, and A ² is a single bond, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a non-aromatic cyclic hydrocarbon group or an aromatic group. A ³ is a hydrocarbon group, A ³ is a single bond, —O—, —NH—, —N (CH ₃ ) —, —CONH—, —NHCO—, —COO—, —OCO—, —CON (CH ₃ ) -, -N (CH ₃ ) CO- or -O (CH ₂ ) _m- (m is an integer of 1 to 5), A ⁴ is a nitrogen-containing aromatic heterocycle, and n is 1 to It is an integer of 4.)

In addition, diamine compounds represented by the following formula [DA19] and formula [DA20] can also be used as other diamine compounds.

The component (b) includes the solubility of the polymer having the repeating unit represented by the formula [1] in the solvent, the coating property of the liquid crystal aligning agent, the alignment property of the liquid crystal when the liquid crystal alignment film is used, and the voltage holding ratio. Depending on the characteristics such as accumulated charge, one kind or a mixture of two or more kinds may be used.

The component (c) is a tetracarboxylic acid derivative, and examples thereof include a tetracarboxylic dianhydride represented by the above formula [3]. In the formula [3], Z ₁ represents the formula [3a], the formula [3c], the formula [3d], the formula [3e] from the viewpoint of easy synthesis and ease of polymerization reactivity when producing a polymer. The structure represented by the formula [3f] or the formula [3g] is preferable. A structure represented by the formula [3a], a formula [3e], a formula [3f] or a formula [3g] is more preferable, and a formula [3a], a formula [3e] or a formula [3f] is particularly preferable. Or it is Formula [3g].

The tetracarboxylic dianhydride represented by the formula [3] is preferably 1 mol% or more of the entire component (c). More preferred is 5 mol% or more, and particularly preferred is 10 mol% or more.

Also, when _{Z 1} formula [3e], using the equation [3f] or tetracarboxylic acid dianhydride represented by the formula [3] is a structure of formula [3 g], the amount used, (c) the entire component It is preferable to set it as 20 mol% or more, More preferably, it is 30 mol% or more. Further, all of the component (c) may be a tetracarboxylic dianhydride represented by the formula [3] in which Z ₁ is a structure of the formula [3e], the formula [3f] or the formula [3g].

Examples of the component (c) other than the tetracarboxylic dianhydride represented by the formula [3] include the following tetracarboxylic acid compounds, tetracarboxylic dianhydrides, and tetracarboxylic acid dihalide compounds. That is, as component (c) other than the tetracarboxylic dianhydride represented by the formula [3], pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalene Tetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7-anthracenetetracarboxylic acid, 1,2,5,6-anthracenetetracarboxylic acid, 3,3 ′, 4 4′-biphenyltetracarboxylic acid, 2,3,3 ′, 4-biphenyltetracarboxylic acid, bis (3,4-dicarboxyphenyl) ether, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, bis (3,4-dicarboxyphenyl) sulfone, bis (3,4-dicarboxyphenyl) methane, 2,2-bis (3,4-dicarboxyphenyl) propane, 1,1,1, , 3,3-hexafluoro-2,2-bis (3,4-dicarboxyphenyl) propane, bis (3,4-dicarboxyphenyl) dimethylsilane, bis (3,4-dicarboxyphenyl) diphenylsilane, 2,3,4,5-pyridinetetracarboxylic acid, 2,6-bis (3,4-dicarboxyphenyl) pyridine, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, 3,4,9 , 10-perylenetetracarboxylic acid or 1,3-diphenyl-1,2,3,4-cyclobutanetetracarboxylic acid.

The component (c) is the solubility of the polymer having the repeating unit represented by the formula [1] in the solvent, the coating property of the liquid crystal aligning agent, the orientation of the liquid crystal when it is used as the liquid crystal alignment film, the voltage holding ratio, the accumulation. One type or a mixture of two or more types can be used depending on the characteristics such as charge.

A polyimide precursor having a repeating unit represented by the formula [1] can be produced by polymerizing such components (a), (b) and (c). For example, when tetracarboxylic dianhydride is used as the component (c), a polyamic acid having a repeating unit represented by the formula [1] can be produced. And the polyamic acid ester which has a repeating unit shown by Formula [1] can be manufactured by converting the carboxyl group of the obtained polyamic acid which has a repeating unit shown by Formula [1] into ester. The polyamic acid having the repeating unit represented by the formula [1] and the polyamic acid ester having the repeating unit represented by the formula [1] are cyclized (imidized) to repeat the compound represented by the formula [1]. A polyimide having units is obtained.

Here, the repeating unit represented by the formula [1] is composed of the component (a) and the component (b). The component (b) and the component (c) constitute a polyimide precursor or a repeating unit of polyimide. The polyimide precursor and the repeating unit of polyimide composed of the component (b) and the component (c) can be represented by, for example, the following formula [8]. In the above formula [1], A ₁ is a group derived from the component (a) which is a raw material, and C ₁ , C ₂ and A ₂ are groups derived from the component (b) which is a raw material. In the above formula [8], C ₁ , C ₂ , and A ₂ are groups derived from the component (b) as a raw material, and Z ₁ is a group derived from the component (c) as a raw material.

(Wherein _{_{[8], A 2, C}} 1, C 2 is the same as the formula [b], _{Z 1} is the same as _{Z 1} in the formula _{[3], R 41} and _{R 42} is a hydrogen atom or C 1-8 alkyl groups, which may be the same or different, and j represents a positive integer.)

The repeating unit represented by the formula [1] of the polymer having the repeating unit represented by the formula [1] has one type each of C ₁ , C ₂ , A ₁ and A ₂ and the same formula [1]. Only the repeating unit shown may be sufficient, and C ₁ , C ₂ , A ₁ and A ₂ may be plural types, and may be a repeating unit represented by plural types of formula [1].

The repeating unit represented by the formula [8] possessed by the polymer having the repeating unit represented by the formula [1] is the same as each of C ₁ , C ₂ , A ₂ , R ₄₁ and R ₄₂ . Only a repeating unit represented by the formula [8] may be used, or a plurality of C ₁ , C ₂ , A ₂ , R ₄₁ and R ₄₂ may be used, and a plurality of repeating units represented by the formula [8] may be used.

The reaction of component (a), component (b) and component (c) is usually carried out in an organic solvent. The organic solvent used at that time is not particularly limited as long as the produced polyimide precursor is dissolved. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, γ- Butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, Ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol Nobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl Ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol Methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane , N-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, pyruvic acid Ethyl, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-metho Shipuropion acid, 3-methoxy propionic acid propyl, 3-methoxy propionic acid butyl, and the like diglyme or 4-hydroxy-4-methyl-2-pentanone. These may be used alone or in combination. Furthermore, even if it is a solvent which does not dissolve a polyimide precursor, you may mix and use the said solvent in the range which the produced | generated polyimide precursor does not precipitate. Moreover, since the water | moisture content in an organic solvent inhibits a polymerization reaction, and also causes the produced polyimide precursor to hydrolyze, it is preferable to use what dehydrated and dried the organic solvent.

Examples of the order of reacting the component (a), the component (b), and the component (c) include a method in which the component (a) and the component (b) are reacted and then the component (c) is added and reacted. It is done. By making it react in this way, the polyimide precursor which has the repeating unit shown by the formula [1] obtained, the repeating unit shown by the formula [1], and the repeating unit shown by the formula [8] were combined at random. Since it becomes a random copolymer, it is preferable.

On the other hand, the step of reacting the component (a) with the component (b) to obtain a urea polymer composed of the repeating unit represented by the formula [1], the reaction of the component (b) with the component (c) 8] to obtain a polyimide precursor composed of a repeating unit represented by formula [1], and then from the urea-based polymer composed of the repeating unit represented by formula [1] and the repeating unit represented by formula [8]. In the method of reacting with the polyimide precursor, the resulting polymer having the repeating unit represented by the formula [1] has a structure like a block copolymer of polyurea and polyimide precursor, that is, the above random copolymer. Compared to the coalescence, each has a polymer structure composed of a urea polymer and a polyimide precursor having a higher degree of polymerization. In this case, problems such as poor solubility and poor applicability when used as a liquid crystal aligning agent may occur.

The temperature at which the component (a), the component (b) and the component (c) are reacted can be selected from -20 ° C to 150 ° C, but is preferably in the range of -5 ° C to 100 ° C. . The reaction can be carried out at an arbitrary concentration. However, if the concentration is too low, it is difficult to obtain a polyimide precursor having a repeating unit represented by the high molecular weight formula [1]. The viscosity becomes too high, and uniform stirring becomes difficult. Therefore, the concentration of the total amount of component (a), component (b) and component (c) is preferably 1 to 50% by mass, more preferably 5 to 30% by mass in the reaction solution. The initial stage of the reaction can be performed at a high concentration, and then an organic solvent can be added.

The proportion of the component (a), the component (b) and the component (c) to be reacted is, for example, a molar ratio, and the total amount of the component (a) and the component (c): (b) component = 0.8: 1 Preferably it is ˜1.2: 1. The proportion of the component (a) in the total amount of the component (a) and the component (c) is preferably 20 mol% to 60 mol% in order to achieve both voltage holding ratio and residual DC. This is because if the proportion of the component (a) is too small, the voltage holding ratio may be lowered during low-temperature firing, and if it is too large, residual DC tends to accumulate.

Further, the polyamic acid having a repeating unit represented by the above formula [1] which is a polyimide precursor and the polyamic acid ester having a repeating unit represented by the above formula [1] are ring-closed (imidized) to form the formula [1 The polyimide which has a repeating unit shown by this can be obtained. However, in the polyimide having the repeating unit represented by the formula [1] contained in the liquid crystal aligning agent used in the method for producing a liquid crystal alignment film of the present invention, the ring closure rate (also referred to as imidation rate) of the amic acid group is 50. Must be less than%. In addition, the imidation rate as used in this specification is a ratio of the imide group which occupies for the total amount of the imide group and carboxyl group derived from tetracarboxylic dianhydride.

Examples of the method for imidizing the polyimide precursor include thermal imidization in which the polyimide precursor solution is heated as it is or catalytic imidization in which a catalyst is added to the polyimide precursor solution.

When the polyimide precursor is thermally imidized in a solution, the temperature is 100 ° C. to 400 ° C., preferably 120 ° C. to 250 ° C., and it is preferable to carry out while removing water generated by the imidation reaction from the system.

The catalyst imidation of the polyimide precursor can be performed by adding a basic catalyst and an acid anhydride to the polyimide precursor solution and stirring at -20 to 250 ° C, preferably 0 to 180 ° C. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times of the amic acid group, and the amount of the acid anhydride is 1 to 50 mol times, preferably 3 to 30 mol of the amido acid group. Is double. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, 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 imidization rate by catalytic imidation can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

When recovering the produced polyimide precursor or polyimide from the polyimide precursor or polyimide reaction solution, the reaction solution may be poured into a solvent and precipitated. Examples of the solvent used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer that has been introduced into the solvent and precipitated can be recovered by filtration, and then dried at normal temperature or under reduced pressure at room temperature or by heating. In addition, when the polymer collected by precipitation is redissolved in an organic solvent and reprecipitation and collection is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the solvent at this time include alcohols, ketones, and hydrocarbons, and it is preferable to use three or more kinds of solvents selected from these because purification efficiency is further increased.

The molecular weight of the polyimide precursor having the repeating unit represented by the above formula [1] used in the present invention and the polyimide having the repeating unit represented by the above formula [1] and having an imidation ratio of less than 50% is determined therefrom. Considering the strength of the obtained liquid crystal alignment film, workability during film formation, and coating properties, the weight average molecular weight measured by GPC (Gel Permeation Chromatography) method is 5,000 to 1,000,000. More preferably, it is 10,000 to 150,000.

A polyimide precursor having a repeating unit represented by the above formula [1] contained in a liquid crystal aligning agent used in the method for producing a liquid crystal alignment film of the present invention, or an imidization having a repeating unit represented by the above formula [1] Although the compounding ratio of the polyimide with a rate of less than 50% is not particularly limited, for example, a polyimide precursor having a repeating unit represented by the above formula [1] and an imidation ratio having a repeating unit represented by the above formula [1] Is less than 50%, the total amount of polyimide is 0.1 to 30% by mass, preferably 3 to 10% by mass.

Moreover, the liquid crystal aligning agent used for manufacture of a liquid crystal aligning film has a polyimide precursor in which a polymer component has a repeating unit shown by said Formula [1], and a repeating unit shown by said Formula [1]. Only a polyimide having an imidation ratio of less than 50% may be used, or other polymers other than these may be mixed. In that case, the content of the other polymer is 0.5 to 15% by mass, preferably 1 to 10% by mass, based on the total amount of the polymer components. Other polymers include polyimide precursors and polyimides that do not have the repeating unit represented by the above formula [1]. Furthermore, an acrylic polymer, a methacryl polymer, polystyrene, polyamide, polysiloxane, etc. are mentioned.

The solvent contained in the liquid crystal aligning agent dissolves a polyimide precursor having a repeating unit represented by the above formula [1] and a polyimide having a repeating unit represented by the above formula [1] and having an imidization ratio of less than 50%. And N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethyl- 2-pyrrolidone, N-vinylpyrrolidone, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl Isoamyl ketone, methyl isopropyl ketone, cyclo Cyclohexanone, ethylene carbonate, propylene carbonate, and organic solvents such as diglyme and 4-hydroxy-4-methyl-2-pentanone. These may be used alone or in combination.

The solvent contained in the liquid crystal aligning agent preferably has a solvent content of 70 to 99.9% by mass from the viewpoint of forming a uniform liquid crystal alignment film by coating. This content can be appropriately changed depending on the film thickness of the target liquid crystal alignment film.

As the liquid crystal aligning agent, an organic solvent that improves the coating properties and surface smoothness of the liquid crystal aligning film when the liquid crystal aligning agent is applied, that is, a poor solvent can be used as long as the effects of the present invention are not impaired.

Specific examples of the poor solvent for improving the coating property and surface smoothness include 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-methylcyclohexanol, 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-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate , Ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, Diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, die Tylene glycol isopropyl ether or diethylene glycol monobutyl ether, propylene glycol, propylene glycol monobutyl ether, 1- (butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tri Propylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono Chill 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, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3- Methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate or Surface tension of a solvent such as lactic isoamyl esters low organic solvent.

These poor solvents may be used alone or in combination. When the above poor solvent is used, it is preferably 5 to 80% by mass, more preferably 20 to 60% by mass, based on the total organic solvent contained in the liquid crystal aligning agent.

The liquid crystal aligning agent is 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, unless the effects of the present invention are impaired. It is also possible to add a crosslinkable compound having at least one substituent 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 crosslinkable compound having at least two oxetane groups represented by the following formula [4].

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 [5].

Specific examples include crosslinkable compounds represented by the formulas [5-1] to [5-42] described on pages 76 to 82 of International Publication No. WO2012 / 01132751 (2012.2.2 publication). 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 such melamine derivatives or benzoguanamine derivatives include MX-750, which has an average of 3.7 substituted methoxymethyl groups per triazine ring, and an average of 5. methoxymethyl groups per triazine ring. Eight-substituted MW-30 (Sanwa Chemical Co., Ltd.) and Cymel 300, 301, 303, 350, 370, 771, 325, 327, 703, 712 and other methoxymethylated melamines, 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 and the like Methoxymethylated etoxy Methylated benzoguanamine, 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 Cyanamide). 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 represented by the formulas [6-1] to [6-48] described on pages 62 to 66 of International Publication No. WO2011 / 132751 (published 2011.10.27). Is mentioned.

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.

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

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

The above compound is an example of a crosslinkable compound and is not limited thereto. Moreover, the crosslinkable compound used for a liquid crystal aligning agent may be one type, and may combine two or more types.

The content of the crosslinkable compound in the liquid crystal aligning agent is preferably 0.1 to 150 parts by mass with respect to 100 parts by mass of all the polymer components. In order for the crosslinking reaction to proceed and to achieve the desired effect, the amount is more preferably 0.1 to 100 parts by weight, and most preferably 1 to 50 parts by weight, based on 100 parts by weight of all polymer components.

As a compound that promotes charge transfer in a liquid crystal alignment film and promotes charge release of a liquid crystal cell using the liquid crystal alignment film when a liquid crystal alignment film using the liquid crystal alignment treatment agent using the composition of the present invention is formed. It is preferable to add nitrogen-containing heterocyclic amine compounds represented by the formulas [M1] to [M156], which are described on pages 69 to 73 of International Publication No. WO2011 / 132751 (published 2011.10.27). . This amine compound may be added directly to the composition, but it may be added after a solution having a concentration of 0.1% by mass to 10% by mass, preferably 1% by mass to 7% by mass with an appropriate solvent. preferable. The solvent is not particularly limited as long as it is an organic solvent that dissolves the specific polyimide polymer described above.

The liquid crystal aligning agent can contain 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, as long as the effects of the present invention are not impaired. Furthermore, you may contain the compound etc. which improve the adhesiveness of a liquid crystal aligning film and a board | substrate.

Examples of compounds that improve 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 use ratio of these surfactants 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. is there.

Specific examples of the compound that improves the adhesion between the liquid crystal alignment film and the substrate include the following functional silane-containing compounds and epoxy group-containing compounds.

For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10- Riethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyl Trimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3- Aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether Polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6- Tetraglycidyl-2,4-hexanediol, N, N, N ′, N ′,-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane or N, N, N ′, N ′,-tetraglycidyl-4,4′-diaminodiphenylmethane and the like.

When using a compound to be adhered to these substrates, the amount is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts per 100 parts by mass of all the polymer components contained in the liquid crystal aligning agent. Part by mass. If it is less than 0.1 part by mass, the effect of improving the adhesion cannot be expected, and if it exceeds 30 parts by mass, the storage stability of the liquid crystal aligning agent may be deteriorated.

In addition to the poor solvent, the crosslinkable compound, the liquid crystal alignment film thickness uniformity and surface smoothness, and the compound that adheres to the substrate, the effect of the present invention is impaired. If it is within the range, a dielectric material or a conductive material for changing the electrical characteristics such as the dielectric constant and conductivity of the liquid crystal alignment film may be added.

In the present invention, such a liquid crystal aligning agent is applied on a substrate and then baked to obtain a liquid crystal aligning film having an imidization ratio of 50 to 70%.

As the substrate, a glass substrate, a silicon wafer, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like can be used depending on the target device. From the viewpoint of simplifying the process, it is preferable to use a substrate on which an ITO (Indium Tin Oxide) electrode or the like for driving the liquid crystal is formed. In the reflective liquid crystal display element, an opaque substrate such as a silicon wafer can be used if only one substrate is used, and a material that reflects light such as aluminum can be used as an electrode in this case. In the present invention, since the firing temperature can be lowered, a plastic substrate or the like which is a substrate having low heat resistance can also be used.

The method of applying the liquid crystal aligning agent to the substrate is not particularly limited, but industrially, by dipping method, roll coater method, slit coater method, spinner method, spray method, screen printing, offset printing, flexographic printing, or inkjet method, etc. The method of performing is common. You may use these according to the objective.

After applying the liquid crystal aligning agent on the substrate, firing is performed. The firing conditions are such that the liquid crystal alignment film obtained after firing has an imidization ratio of 50 to 70%. For example, the firing temperature is 210 ° C. or lower, preferably 120 to 200 ° C. The firing time is, for example, 5 minutes to 2 hours, preferably 10 minutes to 30 minutes. Thus, since it can bake at low temperature, a plastic substrate with low heat resistance can be used. In addition, it is possible to suppress deterioration of the color characteristics of the color filter of the liquid crystal display element due to baking at a high temperature and to reduce the energy cost in manufacturing the liquid crystal display element.

Examples of the heating means for performing firing include a thermal circulation oven or an IR (infrared) oven. If the thickness of the liquid crystal alignment film obtained by firing is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element. If it is too thin, the reliability of the liquid crystal display element may be lowered. More preferably, it is 10 to 100 nm.

When the liquid crystal is horizontally or tilted, the liquid crystal alignment film obtained by baking is treated by rubbing or irradiation with polarized ultraviolet rays. In the case of vertical alignment, etc., it can be used as a liquid crystal alignment film without alignment treatment.

Thus, the liquid crystal aligning agent containing the polyimide precursor which has a repeating unit shown by the said Formula [1], and the polyimide which has a repeating unit shown by the said Formula [1], and an imidation ratio is less than 50%. A liquid crystal alignment film having an imidization ratio of 50 to 60% obtained by coating the substrate on the substrate and baking it has a low imidation ratio, a large amount of carboxyl groups, and a repeating unit represented by the formula [1]. For this reason, as shown in the examples described later, the residual DC is low and the voltage holding ratio is high. On the other hand, for example, in the case of a liquid crystal alignment film composed of a polyurea repeating unit (general formula (I) in Patent Document 1) and a polyimide repeating unit (general formula (II) in Patent Document 1) as in Patent Document 1. The residual DC is very high compared to the present invention. In Patent Document 1, the liquid crystal aligning agent is applied and then fired at a low temperature. However, since the polyimide is formed at the stage of the liquid crystal aligning agent before firing, the imidation ratio of the liquid crystal aligning film obtained in Patent Document 1 Is very high, unlike the present invention.

The liquid crystal display element of the present invention is a liquid crystal display element obtained by applying and baking a liquid crystal aligning agent by the above-described method to obtain a substrate with a liquid crystal alignment film, and then preparing a liquid crystal cell by a known method. To give an example, two substrates arranged to face each other, a liquid crystal layer provided between the substrates, and a method for producing the liquid crystal alignment film of the present invention provided between the substrate and the liquid crystal layer. A liquid crystal display device comprising a liquid crystal cell having a liquid crystal alignment film formed. As such a liquid crystal display element of the present invention, a twisted nematic (TN) method, a vertical alignment (VA) method, a horizontal alignment (IPS: In-Plane Switching) method, an OCB alignment (OCB). There are various types such as Optically Compensated Bend).

As a method for manufacturing a liquid crystal cell, prepare a pair of substrates on which a liquid crystal alignment film is formed, spray spacers on the liquid crystal alignment film of one substrate, and place the other side of the liquid crystal alignment film on the other side. And a method of sealing the substrate by injecting liquid crystal under reduced pressure, or a method of sealing the substrate by bonding the liquid crystal after dropping the liquid crystal on the liquid crystal alignment film surface on which the spacers are dispersed.

Examples of the liquid crystal include a positive liquid crystal having a positive dielectric anisotropy and a negative liquid crystal having a negative dielectric anisotropy. Specifically, for example, MLC-2003, MLC-6608, MLC-6609 manufactured by Merck & Co., Inc. Etc. can be used.

The liquid crystal alignment film of the present invention has a liquid crystal layer between a pair of substrates provided with electrodes, and contains a polymerizable compound that is polymerized by at least one of active energy rays and heat between the pair of substrates. It is also preferably used for a liquid crystal display element produced by a step of polymerizing a polymerizable compound by disposing a liquid crystal composition and applying a voltage between electrodes while at least one of irradiation with active energy rays and heating. Here, ultraviolet rays are suitable as the active energy ray. The wavelength of ultraviolet rays is 300 to 400 nm, preferably 310 to 360 nm. In the case of polymerization by heating, the heating temperature is 40 to 120 ° C, preferably 60 to 80 ° C. Moreover, you may perform an ultraviolet-ray and a heating simultaneously.

The above liquid crystal display element controls the pretilt of liquid crystal molecules by a PSA (Polymer Sustained Alignment) method. For example, in the PSA method using active energy rays, a small amount of a photopolymerizable compound, for example, a photopolymerizable monomer is mixed in a liquid crystal material, a liquid crystal cell is assembled, and a predetermined voltage is applied to the liquid crystal layer. The photopolymerizable compound is polymerized by irradiating it with active energy rays such as ultraviolet rays, and the pretilt of the liquid crystal molecules is controlled by the produced polymer. Since the alignment state of the liquid crystal molecules when this polymer is formed is stored even after the voltage is removed, the pretilt of the liquid crystal molecules can be adjusted by controlling the electric field formed in the liquid crystal layer. it can. The PSA method does not require a rubbing process and is suitable for forming a vertical alignment type liquid crystal layer in which it is difficult to control the pretilt by the rubbing process.

The production of the PSA type liquid crystal cell is the same as described above. A pair of substrates on which a liquid crystal alignment film is formed is prepared, spacers are dispersed on the liquid crystal alignment film of one substrate, and the liquid crystal alignment film surface is on the inside. In this way, the other substrate is bonded and the liquid crystal is injected under reduced pressure to seal, or the liquid crystal is dropped on the liquid crystal alignment film surface on which the spacers are dispersed, and then the substrate is bonded and sealed. Is mentioned.

In the case of the PSA method, the liquid crystal is mixed with a polymerizable compound that is polymerized by irradiation with heat or active energy rays. Examples of the polymerizable compound include compounds having at least one polymerizable unsaturated group such as an acrylate group or a methacrylate group in the molecule. In that case, the polymerizable compound is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the liquid crystal component. When the polymerizable compound is less than 0.01 part by mass, the polymerizable compound does not polymerize and the orientation of the liquid crystal cannot be controlled, and when it exceeds 10 parts by mass, the amount of unreacted polymerizable compound increases and the liquid crystal display The burn-in characteristic of the element is deteriorated.

After producing the liquid crystal cell, the polymerizable compound is polymerized by applying heat or active energy rays while applying an AC or DC voltage to the liquid crystal cell. Thereby, the alignment of the liquid crystal molecules can be controlled.

In addition, the liquid crystal alignment film of the present invention has a liquid crystal layer between a pair of substrates provided with electrodes, and a polymerizable group that is polymerized by at least one of active energy rays and heat between the pair of substrates. It can also be used for a liquid crystal display device manufactured through a step of polymerizing a polymerizable group while disposing a liquid crystal alignment film containing a polymer and applying a voltage between electrodes (SC-PVA). Here, ultraviolet rays are suitable as the active energy ray. The wavelength of ultraviolet rays is 300 to 400 nm, preferably 310 to 360 nm. In the case of polymerization by heating, the heating temperature is 40 to 120 ° C, preferably 60 to 80 ° C. Moreover, you may perform an ultraviolet-ray and a heating simultaneously.

In order to obtain a liquid crystal alignment film containing a polymerizable group that polymerizes from at least one of active energy rays and heat, a method of adding a compound containing this polymerizable group to the liquid crystal aligning agent can be mentioned. Moreover, the polyimide precursor which has a repeating unit shown by the said Formula [1] contained in a liquid crystal aligning agent by using the compound containing a polymeric group as (a) component, (b) component, or (c) component etc. And a polyimide having a repeating unit represented by the above formula [1] and having an imidization ratio of less than 50% include a polymerizable group.

Then, after preparing a pair of substrates on which a liquid crystal alignment film containing a polymerizable group that is polymerized by at least one of active energy rays and heat is prepared, the liquid crystal alignment film on one substrate is formed in the same manner as described above. Sprinkle spacers on the liquid crystal alignment film so that the surface of the liquid crystal alignment film is on the inside, and bond the other substrate, inject liquid crystal under reduced pressure, or seal the liquid crystal on the liquid crystal alignment film surface on which the spacers are distributed. A liquid crystal cell can be manufactured by a method in which the substrate is attached and sealed after dropping.

And after producing the liquid crystal cell, the orientation of the liquid crystal molecules can be controlled by irradiating the liquid crystal cell with heat or active energy rays while applying an AC or DC voltage.

As described above, the liquid crystal display device manufactured using the liquid crystal alignment film of the present invention has a low residual DC and a high voltage holding ratio, and thus has excellent reliability, and has a large screen and a high-definition liquid crystal. It can be suitably used for a television. In addition, since the firing temperature is low, a lightweight plastic or the like can be used as the substrate, and the weight of the liquid crystal display element can be reduced.

Hereinafter, an example will be given and described. In addition, this invention is limited to these and is not interpreted. Abbreviations used below are as follows.

(Diisocyanate)
A-1: Tolylene 2,4-diisocyanate

(Tetracarboxylic dianhydride)
B-1: 1,2,3,4-cyclobutanetetracarboxylic dianhydride

(Diamine compound)
C-1: 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane C-2: N- (3-picolyl) -3,5-diaminobenzamide C-3: 1,3-diamino-4 -{4- (4-n-heptylcyclohexyl) phenoxy} benzene

(Organic solvent)
NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve

The measurement method performed in this example will be described below.
(Measurement of molecular weight of polymer)
The molecular weights of polyamic acid and polyimide were determined by measuring the polyamic acid and polyimide with a GPC (room temperature gel permeation chromatography) apparatus, and calculating the number average molecular weight and weight average molecular weight as polyethylene glycol and polyethylene oxide equivalent values.
GPC device: Showa Denko GPC-101,
Column: Shodex column (KD-803, KD-805 in series)
Column temperature: 50 ° C
Eluent: N, N′-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H ₂ O) is 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) is 30 mmol / L, Tetrahydrofuran (THF) 10ml / L)
Flow rate: 1.0 ml / standard sample for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation and polyethylene glycol (manufactured by Polymer Laboratories) (Molecular weight about 12,000, 4,000, 1,000)

(Measurement of imidization ratio of polyimide)
The imidation ratio of polyimide was measured as follows.

20 mg of polyimide powder was placed in an NMR sample tube, and 0.53 ml of deuterated dimethyl sulfoxide (DMSO-d ₆ , 0.05% TMS (tetramethylsilane) mixture) was added and completely dissolved. This solution was measured for proton NMR at 500 MHz with an NMR measuring instrument (JNM-ECA500) manufactured by JEOL Datum. The imidation rate is determined based on protons derived from structures that do not change before and after imidation as reference protons, and the peak integrated value of these protons and proton peaks derived from NH groups of amic acid appearing in the vicinity of 9.5 ppm to 10.0 ppm. It calculated | required by following Formula using the integrated value.
Imidization rate (%) = (1−α · x / y) × 100

In the above formula, x is the proton peak integrated value derived from the NH group of the amic acid, y is the peak integrated value of the reference proton, and α is one NH group proton of the amic acid in the case of polyamic acid (imidation rate is 0%). The number ratio of the reference protons.

<Synthesis Example 1>
A-1 (1.56 g, 9.00 mmol), C-1 (1.53 g, 8,98 mmol), C-2 (1.30 g, 5.36 mmol), C-3 (1.37 g, 3.59 mmol) ) Was mixed in NMP (23 g) and reacted at 40 ° C. for 15 hours, then B-1 (1.65 g, 8.46 mmol) and NMP (19 g) were added, and the mixture was further reacted for 6 hours to react with polymer solution A ( A solution of a polyamic acid having a repeating unit represented by the above formula [1]) (polymer concentration 15% by mass) was obtained. The number average molecular weight of this polymer was 16,020, and the weight average molecular weight was 49,319.

<Synthesis Example 2>
A-1 (0.783 g, 4.50 mmol), C-1 (1.53 g, 8,98 mmol), C-2 (1.30 g, 5.36 mmol), C-3 (1.37 g, 3.59 mmol) ) Was mixed in NMP (19 g) and reacted at 40 ° C. for 15 hours, then B-1 (2.63 g, 13.4 mmol) and NMP (23 g) were added, and the mixture was further reacted for 6 hours to react with polymer solution B ( A solution of a polyamic acid having a repeating unit represented by the above formula [1]) (polymer concentration 15% by mass) was obtained. The number average molecular weight of this polymer was 11,555, and the weight average molecular weight was 37,656.

<Comparative Synthesis Example 1>
A-1 (3.82 g, 21.9 mmol), C-1 (1.87 g, 10.9 mmol), C-2 (1.59 g, 6.59 mmol), C-3 (1.67 g, 4.38 mmol) ) Was mixed in NMP (50 g) and reacted at 40 ° C. for 15 hours to obtain a polymer solution C (polyurea solution) (polymer concentration: 15% by mass). The number average molecular weight of this polymer was 12,731, and the weight average molecular weight was 32,967.

<Comparative Synthesis Example 2>
B-1 (3.35 g, 17.0 mmol), C-1 (1.53 g, 8,98 mmol), C-2 (1.30 g, 5.36 mmol), C-3 (1.37 g, 3.59 mmol) ) Was mixed in NMP (42 g) and then reacted at 40 ° C. for 15 hours to obtain a polymer solution D (polyamic acid solution) (polymer concentration: 15% by mass). The number average molecular weight of this polymer was 14,833, and the weight average molecular weight was 38,984.

<Comparative Synthesis Example 3>
After adding NMP to the polymer solution A (20 g) described in Synthesis Example 1 and diluting to a concentration of 6% by mass, acetic anhydride (3.65 g) and pyridine (1.70 g) were added as imidization catalysts, The reaction was carried out at 50 ° C. for 3 hours. The reaction solution was poured into methanol (200 g), and the produced precipitate was separated by filtration. This precipitate was washed with methanol and dried under reduced pressure at 100 ° C. to obtain a white powder. The imidation ratio of this polyimide was 100%, the number average molecular weight was 13,084 and the weight average molecular weight was 40,857.

After 11.3 g of NMP was added to 1.99 g of this powder and dissolved by stirring at 50 ° C. for 30 hr, polymer solution E (having a repeating unit represented by the above formula [1] and having an imidization rate of 100% (Polyimide solution) (polymer concentration 15% by mass).

<Example 1> Preparation of liquid crystal aligning agent and production of liquid crystal cell To polymer solution A obtained in Synthesis Example 1, NMP and BCS were added and stirred, and the polymer was 6 mass%, NMP was 64 mass%, and BCS was It prepared so that it might become 30 mass%. This solution was pressure filtered through a membrane filter having a pore size of 1 μm to obtain a liquid crystal aligning agent.

The obtained liquid crystal aligning agent was spin-coated on a glass substrate with an ITO electrode, dried on an 80 ° C. hot plate for 5 minutes, and then baked in an IR oven at 180 ° C. for 15 minutes to form a coating film having a film thickness of 100 nm. A (liquid crystal alignment film) was formed to obtain a substrate with a liquid crystal alignment film. Two substrates with this liquid crystal alignment film are prepared, a spacer of 4 μm is sprayed on the surface of one liquid crystal alignment film, a sealant is printed thereon, and the other substrate has a liquid crystal alignment film surface. After laminating so as to face each other, the sealing agent was cured to produce an empty cell. Liquid crystal MLC-6608 (manufactured by Merck Japan Co., Ltd.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain a liquid crystal cell.

<Example 2 and Comparative Examples 1 to 3>
Liquid crystal alignment in the same manner as in Example 1 except that the polymer solutions B to E obtained in Synthesis Example 2 and Comparative Synthesis Examples 1 to 3 were used instead of the polymer solution A obtained in Synthesis Example 1, respectively. An agent, a liquid crystal alignment film, and a liquid crystal cell were obtained.

<Example 3>
A liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal cell were obtained in the same manner as in Example 1 except that the firing temperature was 200 ° C.

<Comparative example 4>
A liquid crystal aligning agent, a liquid crystal aligning film and a liquid crystal cell were obtained in the same manner as in Example 1 except that the baking temperature was 230 ° C.

<Example 4>
NMP and BCS were added to the polymer solution A obtained in Synthesis Example 1 and stirred to prepare a polymer of 3.5% by mass, NMP of 66.5% by mass, and BCS of 30% by mass. This solution was filtered under pressure through a membrane filter having a pore size of 1 μm, stored at −15 ° C. for 48 hours, and then evaluated for ink jet coating properties. As the ink jet coater, HIS-200 (manufactured by Hitachi Plant Technology) was used. Application was performed on an ITO (indium tin oxide) vapor-deposited substrate cleaned with pure water and IPA at a nozzle pitch of 0.423 mm, a scan pitch of 0.5 mm, and an application rate of 40 mm / sec. The film is then left for 60 seconds, dried on a hot plate at 80 ° C. for 5 minutes, and then baked in an IR oven at 180 ° C. for 15 minutes to form a coating film (liquid crystal alignment film) having a film thickness of 100 nm. A substrate with a film was obtained, and a liquid crystal cell was obtained in the same manner as in Example 1.

<Measurement of voltage holding ratio>
A voltage of 1 V was applied to the liquid crystal cells obtained in Examples 1 to 4 and Comparative Examples 1 to 4 at a temperature of 80 ° C. for 60 μs, and the voltage after 50 ms was measured to determine how much the voltage was maintained. The voltage holding rate was evaluated. The results are shown in Table 1.

<Measurement of residual DC>
To the liquid crystal cells obtained in Examples 1 to 4 and Comparative Examples 1 to 4, 30 Hz, an AC voltage of 6 Vpp, and a DC voltage of 1 V were applied and driven at a temperature of 23 ° C. for 24 hours. Thereafter, flicker was evaluated, and an applied voltage at which the intensity was minimized was defined as residual DC (flicker erasing method). The results are shown in Table 1.

<Preparation of liquid crystal cell and evaluation of liquid crystal alignment (PSA cell)>
Using a solution obtained by pressure-filtering the polymer solution A obtained in Example 1 and the polymer solution B obtained in Example 2 through a membrane filter having a pore diameter of 1 μm and storing at −15 ° C. for 48 hours, a liquid crystal cell And evaluation of liquid crystal orientation (PSA cell) were performed. This solution was washed with pure water and IPA at the center with a 10 × 10 mm substrate with an ITO electrode having a pattern spacing of 20 μm (length 40 mm × width 30 mm, thickness 0.7 mm) and a substrate with an ITO electrode 10 × 40 mm at the center. After spin-coating on the ITO surface (length 40 mm x width 30 mm, thickness 0.7 mm), drying on an 80 ° C hot plate for 5 minutes, firing in an IR oven at 180 ° C for 15 minutes, A 100 nm coating film (liquid crystal alignment film) was formed to obtain a substrate with a liquid crystal alignment film. After the coated surface was washed with pure water, it was heat-treated at 100 ° C. for 15 minutes in a heat circulation type clean oven to obtain a substrate with a liquid crystal alignment film.

This substrate with a liquid crystal alignment film was combined with a liquid crystal alignment film surface inside, with a 6 μm spacer in between, and the periphery was adhered with a sealant to produce an empty cell. The polymerizable compound represented by the following formula [9] was added to nematic liquid crystal (MLC-6608) (manufactured by Merck Japan) by 100% by mass of nematic liquid crystal (MLC-6608) by vacuum injection into this empty cell. Was injected with a liquid crystal mixed with 0.3% by mass of a polymerizable compound represented by the following formula [9], and the inlet was sealed to obtain a liquid crystal cell.

While applying an AC voltage of 5 V to the obtained liquid crystal cell, using a metal halide lamp with an illuminance of 60 mW, the wavelength of 350 nm or less was cut, and ultraviolet irradiation of 20 J / cm ^{2 in} terms of 365 nm was performed, and the alignment direction of the liquid crystal A liquid crystal cell (PSA cell) was controlled. The temperature in the irradiation apparatus when the liquid crystal cell was irradiated with ultraviolet rays was 50 ° C.

The response speed of the liquid crystal before and after UV irradiation of this liquid crystal cell was measured. As the response speed, T90 → T10 from 90% transmittance to 10% transmittance was measured.

In the PSA cell obtained in the example, the response speed of the liquid crystal cell after the ultraviolet irradiation was faster than that of the liquid crystal cell before the ultraviolet irradiation, so that it was confirmed that the alignment direction of the liquid crystal was controlled. Further, in any liquid crystal cell, it was confirmed by observation with a polarizing microscope (ECLIPSE E600WPOL) (manufactured by Nikon Corporation) that the liquid crystal was uniformly aligned.

<Measurement of imidation ratio of liquid crystal alignment film>
In Examples 1 to 4 and Comparative Examples 1 to 4, the imidization ratio of the liquid crystal alignment film was measured when the substrate with the liquid crystal alignment film was obtained. The method for measuring the imidation ratio of the liquid crystal alignment film is as follows. A liquid crystal aligning agent is spin-coated on a glass substrate with an ITO electrode, dried on a hot plate at 80 ° C. for 5 minutes, and then baked in an IR oven to form a coating film (liquid crystal alignment film) having a film thickness of 100 nm. Thus, a substrate with a liquid crystal alignment film was obtained. This liquid crystal alignment film was shaved off with a cutter knife, and the imidization rate was measured by KBr method with FT-IR.

As a result, as shown in Table 1, the imidation ratio was 50 to 70% using the liquid crystal aligning agents of Examples 1 to 4 containing the polyimide precursor having the repeating unit represented by the formula [1]. In the liquid crystal cell having the liquid crystal alignment film, the voltage holding ratio was high and the residual DC was small. On the other hand, in the liquid crystal cell of Comparative Example 1 having a liquid crystal alignment film composed only of polyurea, the voltage holding ratio was high, but the residual DC was high. Moreover, although the residual DC was small in the liquid crystal cell which has the liquid crystal aligning film which does not have the repeating unit represented by Formula [1] of the comparative example 2, and consists only of polyamic acid, the voltage holding rate was low. Further, in the liquid crystal cells of Comparative Example 3 and Comparative Example 4 having the liquid crystal alignment film having a high imidization rate, the voltage holding ratio was high, but the residual DC was large. In addition, since the electrical characteristics such as residual DC and voltage holding ratio can be measured, it can be said that the measured liquid crystal alignment film has good liquid crystal alignment.

Claims

Contains at least one polymer selected from a polyimide precursor having a repeating unit represented by the following formula [1] and a polyimide having a repeating unit represented by the following formula [1] and having an imidation ratio of less than 50% A method for producing a liquid crystal alignment film, characterized in that a liquid crystal alignment film having an imidization ratio of 50 to 70% is obtained by applying a liquid crystal aligning agent to the substrate and then baking the liquid crystal aligning agent.

(In Formula [1], A 1 is a divalent organic group, A 2 is a divalent organic group, C 1 and C 2 are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, It can be the same or different.)
The method for producing a liquid crystal alignment film according to claim 1, wherein the baking is performed at 210 ° C. or lower.
The method for producing a liquid crystal alignment film according to claim 1, wherein the polymer has a side chain represented by the following formula [2].

(In the formula [2], Y 1 is a single bond, — (CH 2 ) a — (a is an integer of 1 to 15), —O—, —CH 2 O—, —COO— or —OCO—. Y 2 is a single bond or — (CH 2 ) b — (b is an integer of 1 to 15), Y 3 is a single bond, — (CH 2 ) c — (c is an integer of 1 to 15) ), —O—, —CH 2 O—, —COO— or —OCO—, wherein Y 4 is a carbon having a divalent cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, or a steroid skeleton A divalent organic group having 17 to 51, wherein any hydrogen atom on the cyclic group contains an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, or fluorine having 1 to 3 carbon atoms alkyl group may be substituted with a fluorine-containing alkoxyl group or a fluorine atom having 1 to 3 carbon atoms, Y 5 Baie A divalent cyclic group selected from a zen ring, a cyclohexane ring and a heterocyclic ring, wherein any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, carbon The fluorine-containing alkyl group having 1 to 3 carbon atoms, the fluorine-containing alkoxyl group having 1 to 3 carbon atoms or the fluorine atom may be substituted, n is an integer of 0 to 4, and Y 6 has 1 to 18 carbon atoms. An alkyl group, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 18 carbon atoms.)
The production of the liquid crystal alignment film according to any one of claims 1 to 3, wherein the polymer is obtained by reacting the following components (a), (b) and (c): Method.
(A) Component: Compound containing two isocyanate groups in the molecule (b) Component: Compound containing two primary or secondary amino groups in the molecule (c) Component: Tetracarboxylic acid derivative
The method for producing a liquid crystal alignment film according to claim 4, wherein the component (b) is a compound having a side chain represented by the formula [2].
The method for producing a liquid crystal alignment film according to claim 4, wherein the component (b) is a compound represented by the following formula [2a].

(In the formula [2a], Y 1 is a single bond, — (CH 2 ) a — (a is an integer of 1 to 15), —O—, —CH 2 O—, —COO— or —OCO—. Y 2 is a single bond or — (CH 2 ) b — (b is an integer of 1 to 15), Y 3 is a single bond, — (CH 2 ) c — (c is an integer of 1 to 15) ), —O—, —CH 2 O—, —COO— or —OCO—, wherein Y 4 is a carbon having a divalent cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, or a steroid skeleton A divalent organic group having 17 to 51, wherein any hydrogen atom on the cyclic group contains an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, or fluorine having 1 to 3 carbon atoms alkyl group may be substituted with a fluorine-containing alkoxyl group or a fluorine atom having 1 to 3 carbon atoms, Y 5 is A divalent cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, and any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, carbon The fluorine-containing alkyl group having 1 to 3 carbon atoms, the fluorine-containing alkoxyl group having 1 to 3 carbon atoms or the fluorine atom may be substituted, n is an integer of 0 to 4, and Y 6 has 1 to 18 carbon atoms. An alkyl group, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 18 carbon atoms, and m is an integer of 1 to 4; Y 1 -Y 2 -Y 3 -Y 4 - (Y 5) n -Y 6) m is a substituent Y 1 -Y 2 -Y 3 -Y 4 - (Y 5) that n -Y 6 is the m And when m is 2 or more, each substituent may be the same or different. It may be.)
The method for producing a liquid crystal alignment film according to any one of claims 4 to 6, wherein the component (c) is a tetracarboxylic dianhydride represented by the following formula [3].

(In the formula [3], Z 1 is a structure represented by the following formulas [3a] to [3j]).

(In the formula [3a], Z 2 to Z 5 are a hydrogen atom, a methyl group, a chlorine atom or a benzene ring, and may be the same or different. In the formula [3g], Z 6 and Z 7 Are hydrogen atoms or methyl groups, which may be the same or different.
8. The method for producing a liquid crystal alignment film according to claim 1, wherein the polymer in the liquid crystal alignment agent is 0.1 to 30% by mass.
The method for producing a liquid crystal alignment film according to any one of claims 1 to 8, wherein the coating is performed by an inkjet method.
A liquid crystal alignment film manufactured by the method for manufacturing a liquid crystal alignment film according to any one of claims 1 to 9.
A liquid crystal alignment film comprising a polyimide having a repeating unit represented by the following formula [1] and having an imidization ratio of 50 to 70%.

(In Formula [1], A 1 is a divalent organic group, A 2 is a divalent organic group, C 1 and C 2 are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, It can be the same or different.)
A liquid crystal composition comprising a liquid crystal layer between a pair of substrates provided with electrodes and comprising a polymerizable compound that is polymerized by at least one of active energy rays and heat is disposed between the pair of substrates, and the electrodes 12. The liquid crystal alignment film according to claim 10, wherein the liquid crystal alignment film is used for a liquid crystal display device manufactured through a step of polymerizing the polymerizable compound while applying a voltage therebetween.
A liquid crystal layer between a pair of substrates provided with electrodes, and a liquid crystal alignment film containing a polymerizable group that is polymerized by at least one of active energy rays and heat between the pair of substrates; 12. The liquid crystal alignment film according to claim 10, wherein the liquid crystal alignment film is used for a liquid crystal display device produced through a step of polymerizing the polymerizable group while applying a voltage therebetween.
A liquid crystal display element comprising the liquid crystal alignment film according to any one of claims 10 to 13.
A liquid crystal aligning agent comprising a polyimide precursor having a repeating unit represented by the following formula [1].

(In Formula [1], A 1 is a divalent organic group, A 2 is a divalent organic group, C 1 and C 2 are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, It can be the same or different.)