CN114540044A

CN114540044A - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal element

Info

Publication number: CN114540044A
Application number: CN202111350292.8A
Authority: CN
Inventors: 安池伸夫; 西村达哉; 藤下翔平
Original assignee: JSR Corp
Current assignee: JSR Corp
Priority date: 2020-11-25
Filing date: 2021-11-15
Publication date: 2022-05-27
Also published as: KR20220072741A; JP2022083973A; TW202221062A

Abstract

The invention provides a liquid crystal aligning agent, a liquid crystal alignment film and a liquid crystal element. The invention makes the liquid crystal orientation agent contain polymer [ P ] with partial structure (A) in main chain]The partial structure (A) is at least one selected from the group consisting of a partial structure represented by formula (1-1) and a partial structure represented by formula (1-2). In the formula, B¹Is a substituted or unsubstituted aromatic ring. R¹To utilize-C (R)¹⁰)(R¹¹)‑、‑O‑、‑S‑、‑CO‑、‑COO‑、‑NR⁴‑、‑CO‑NR⁴‑、‑NR⁴-CO-O-or-NR⁴‑CO‑NR⁵And form a condensed ring in the formula (1-1)Or a divalent organic group to which a carbon atom constituting the condensed ring in the formula (1-2) is bonded. R²Is a monovalent organic group. R³Is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms.

Description

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

Technical Field

The invention relates to a liquid crystal aligning agent, a liquid crystal alignment film and a liquid crystal element.

Background

Liquid crystal elements are used in a wide range of applications from relatively large display devices such as liquid crystal televisions and information displays (information displays) to small display devices such as smart phones. The performance of the liquid crystal device is determined by various characteristics such as the alignment property of the liquid crystal, the magnitude of the pretilt angle, and the voltage holding ratio. In order to improve the performance of liquid crystal elements, in addition to improvement of liquid crystal materials, improvement of liquid crystal alignment films for aligning liquid crystals in a certain direction has been conventionally performed (for example, see patent documents 1 and 2).

Patent document 1 discloses a liquid crystal aligning agent containing a polyamic acid and a derivative thereof, which is a reaction product of tetracarboxylic dianhydride and diamine, wherein the liquid crystal aligning agent contains a polyamic acid obtained by using bis (5-aminobenzimidazole) benzene as a diamine. Patent document 2 discloses a polyimide obtained by using 5-amino-2- (4-aminophenyl) benzimidazole as a diamine in a liquid crystal aligning agent.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent application laid-open No. 2010-54872

[ patent document 2] Japanese patent laid-open No. 2015-106156

Disclosure of Invention

[ problems to be solved by the invention ]

In recent years, with the high definition of liquid crystal elements, the requirements for quality have become more stringent. In order to satisfy such a demand, the liquid crystal device is required to have further excellent liquid crystal alignment properties and voltage holding ratios. Further, as characteristics of the liquid crystal device, it is required to have a high voltage holding ratio even in a long-term use and to have excellent reliability.

The present invention has been made in view of the above problems, and a main object of the present invention is to provide a liquid crystal aligning agent which can obtain a liquid crystal device having good liquid crystal alignment properties, high voltage holding ratio, and excellent reliability.

[ means for solving problems ]

The present inventors have made extensive studies to solve the above problems, and as a result, they have found that the above problems can be solved by using a polymer having a condensed ring structure in which an aromatic ring and an imidazole ring are condensed with each other in the main chain, and have completed the present invention. Specifically, the present invention provides the following means.

< 1 > A liquid crystal aligning agent comprising a polymer [ P ] having a partial structure (A) in the main chain, wherein the partial structure (A) is at least one selected from the group consisting of a partial structure represented by the following formula (1-1) and a partial structure represented by the following formula (1-2).

[ solution 1]

(in the formulae (1-1) and (1-2), B¹Is a substituted or unsubstituted aromatic ring, and forms a condensed ring structure with the nitrogen-containing heterocyclic ring in the formula (1-1) and the formula (1-2). R¹To utilize-C (R)¹⁰)(R¹¹)-、-O-、-S-、-CO-、-COO-、-NR⁴-、-CO-NR⁴-、-NR⁴-CO-O-or-NR⁴-CO-NR⁵A divalent organic group bonded to a nitrogen atom constituting the condensed ring in the formula (1-1) or a carbon atom constituting the condensed ring in the formula (1-2). R¹⁰And R¹¹Each independently is a hydrogen atom or an alkyl group. R⁴And R⁵Each independently a hydrogen atom or a monovalent organic group. R²Is a monovalent organic group; r is³Is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms. "" indicates a bond. )

< 2 > a liquid crystal alignment film formed using the liquid crystal aligning agent < 1 >.

< 3 > a liquid crystal cell comprising said < 2 > liquid crystal alignment film.

[ Effect of the invention ]

According to the liquid crystal aligning agent of the present invention, a liquid crystal device having good liquid crystal alignment properties, high voltage holding ratio and excellent reliability can be obtained.

Detailed Description

Liquid crystal aligning agent

Hereinafter, each component contained in the liquid crystal aligning agent of the present disclosure and other components optionally blended will be described.

In the present specification, the term "hydrocarbon group" is intended to include chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The "chain hydrocarbon group" refers to a straight-chain hydrocarbon group and a branched hydrocarbon group having no cyclic structure in the main chain and consisting of only a chain structure. The polymer may be saturated or unsaturated. The "alicyclic hydrocarbon group" refers to a hydrocarbon group containing only an alicyclic hydrocarbon structure as a ring structure and not an aromatic ring structure. The alicyclic hydrocarbon group does not need to be composed of only the structure of the alicyclic hydrocarbon, and includes a group having a chain structure in a part thereof. The "aromatic hydrocarbon group" refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. In addition, the structure may not be composed of only an aromatic ring structure, and may include a chain structure or an alicyclic hydrocarbon structure in a part thereof. The term "aromatic ring" means an aromatic hydrocarbon ring or an aromatic heterocyclic ring. The "organic group" refers to a group having a hydrocarbon group having 1 or more carbon atoms.

The disclosed liquid crystal aligning agent contains a polymer [ P ] having a partial structure (A) in the main chain, wherein the partial structure (A) is at least one selected from the group consisting of a partial structure represented by the following formula (1-1) and a partial structure represented by the following formula (1-2).

[ solution 2]

(in the formulae (1-1) and (1-2), B¹Is a substituted or unsubstituted aromatic ring, and forms a condensed ring structure with the nitrogen-containing heterocyclic ring in the formula (1-1) and the formula (1-2). R is¹To utilize-C (R)¹⁰)(R¹¹)-、-O-、-S-、-CO-、-COO-、-NR⁴-、-CO-NR⁴-、-NR⁴-CO-O-or-NR⁴-CO-NR⁵A divalent organic group bonded to a nitrogen atom constituting the condensed ring in the formula (1-1) or a carbon atom constituting the condensed ring in the formula (1-2). R¹⁰And R¹¹Each independently is a hydrogen atom or an alkyl group. R⁴And R⁵Each independently a hydrogen atom or a monovalent organic group. R²Is a monovalent organic group. R³Is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms. "" indicates a bond. )

< Polymer [ P ] >)

Concerning the partial structure (A)

In the formulae (1-1) and (1-2), R¹Provided that-C (R) is utilized¹⁰)(R¹¹)-、-O-、-S-、-CO-、-COO-、-NR⁴-、-CO-NR⁴-、-NR⁴-CO-O-or-NR⁴-CO-NR⁵- (hereinafter, also referred to as "linking group L") may be bonded to the condensed rings in the above-mentioned formulae (1-1) and (1-2). In addition, in R¹when-COO-is bonded to the nitrogen atom constituting the condensed ring in the formula (1-1) or the carbon atom constituting the condensed ring in the formula (1-2), the-COO-may be bonded to the nitrogen atom or the carbon atom in the condensed ring by either-CO-or-O-. In addition, similarly, in R¹By using-CO-NR⁴-or-NR⁴-CO-O-in the case of being bonded to the nitrogen atom constituting the condensed ring in formula (1-1) or the carbon atom constituting the condensed ring in formula (1-2), -CO-NR⁴-and-NR⁴-CO-O-available-NR⁴And with the nitrogen or carbon atoms of the condensed ring, or with-CO-or-O-. As R¹Examples thereof include a divalent group having a chain structure and a divalent group having a cyclic structure.

In the linking group L, R¹⁰And R¹¹Preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom (i.e., -C (R)¹⁰)(R¹¹) -in the case of methylene). R⁴And R⁵The monovalent organic group is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms or a monovalent releasable group which is releasable by heat or light(hereinafter, also simply referred to as "leaving group"). At R⁴、R⁵In the case of a monovalent hydrocarbon group, the monovalent hydrocarbon group is preferably an alkyl group having 1 to 3 carbon atoms or a phenyl group, and more preferably an alkyl group having 1 to 3 carbon atoms.

At R⁴And R⁵Among them, the releasable group is preferably a monovalent group which is released by heat and substituted with a hydrogen atom (hereinafter, also referred to as "thermally releasable group"). Specific examples of the thermally releasable group include groups generally used as a protective group for an amino group, and examples thereof include: urethane-based protecting groups, amide-based protecting groups, imide-based protecting groups, sulfonamide-based protecting groups, and the like. Among them, a urethane-based protecting group is preferable in terms of high releasability by heat. As R⁴、R⁵R when it is a leaving group⁴、R⁵Specific examples of (3) include: t-butoxycarbonyl, benzyloxycarbonyl, 1-dimethyl-2-haloethoxycarbonyl, allyloxycarbonyl, 2- (trimethylsilyl) ethoxycarbonyl, and the like. Among them, a tert-butoxycarbonyl (Boc) group is particularly preferable in terms of excellent releasability by heat and a reduction in the remaining amount of the released structure in the film.

Wherein R is⁴And R⁵Preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a thermally releasable group, more preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a tert-butoxycarbonyl group.

In terms of improving the Voltage Holding Ratio (VHR) of a liquid crystal element, obtaining a liquid crystal element with less decrease in the voltage holding ratio even when driven for a long time and high reliability, and obtaining a liquid crystal element showing good liquid crystal alignment properties, R is¹Preferably, the main chain has a chain hydrocarbon structure having 1 or more carbon atoms. In particular, R¹Preferably a divalent chain hydrocarbon group having 1 or more carbon atoms, or a chain hydrocarbon group having 2 or more carbon atoms, optionally containing methylene groups, through-O-, -S-, -CO-, -COO-, -NR-under non-adjacent conditions⁴-、-CO-NR⁴-、-NR⁴-CO-O-or-NR⁴-CO-NR⁵A divalent radical derived from substitution. In addition, with respect to R⁴And R⁵The specific examples and preferred examples of (c) can be applied to the above description (the same shall apply hereinafter).

At R¹In the case of a divalent chain hydrocarbon group, the chain hydrocarbon group may be straight or branched. In terms of being able to improve the voltage holding ratio of the liquid crystal element, being able to obtain a highly reliable liquid crystal element with little decrease in the voltage holding ratio even when driven for a long time, and being able to obtain a liquid crystal element showing good liquid crystal alignment properties, R is¹The chain hydrocarbon group (b) is preferably an alkanediyl group, and more preferably a straight-chain alkanediyl group. At R¹In the case of a divalent chain hydrocarbon group, the number of carbons of the chain hydrocarbon group is preferably 2 or more, and more preferably 3 or more, from the viewpoint of obtaining a liquid crystal device exhibiting a high voltage holding ratio and from the viewpoint of obtaining a liquid crystal device exhibiting good liquid crystal alignment properties. In addition, from the viewpoint of achieving both improvement in film strength (and further improvement in friction resistance) and improvement in voltage holding ratio of the liquid crystal element, R is¹R in the case of a chain hydrocarbon group¹The number of carbon atoms of (a) is preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less.

At R¹Any methylene group of a chain hydrocarbon group containing-O-, -S-, -CO-, -COO-, -NR⁴-、-CO-NR⁴-、-NR⁴-CO-O-or-NR⁴-CO-NR⁵In the case of a divalent group formed by substitution, the above description can be applied to specific examples and preferable examples of the chain hydrocarbon group.

In the partial structure represented by the formula (1-1), R is a group having good liquid crystal alignment properties, high reliability and high VHR, from the viewpoint of obtaining a liquid crystal element having high VHR¹Preferably by using-C (R)¹⁰)(R¹¹)-、-CO-、-COO-、-NR⁴-、-CO-NR⁴-、-NR⁴-CO-O-or-NR⁴-CO-NR⁵A divalent organic radical bonded, more preferably by means of-C (R)¹⁰)(R¹¹) -a bonded divalent organic radical.

Among them, from the viewpoint of achieving high VHR, high reliability and excellent liquid crystal alignment of a liquid crystal element, R is¹Preferably, the alkyl group is bonded to the formula (1-1) and the formula (A)1-2) a condensed ring-bonded divalent organic group. In particular, R¹Preferably a divalent chain hydrocarbon group having 1 or more carbon atoms, or a chain hydrocarbon group having-O-, -S-, -CO-, -COO-, -NR-in the carbon-carbon bond⁴-、-CO-NR⁴-、-NR⁴-CO-O-or-NR⁴-CO-NR⁵A divalent organic radical of (a).

In the formula (1-2), as R²Examples thereof include monovalent hydrocarbon groups having 1 to 10 carbon atoms and dissociative groups. R in the partial structure represented by the formula (1-2)²Is a structure of an organic radical, with R²It is preferable that the hydrogen atom is a hydrogen atom because it can realize a good liquid crystal alignment property and a high voltage holding ratio. With respect to R²Specific examples and preferred examples of the leaving group are shown, and the R may be used⁴And R⁵The following are descriptions of the leaving group (c). In view of obtaining a liquid crystal element exhibiting good liquid crystal alignment properties and in view of improving the viewing angle characteristics of the liquid crystal element by forming the liquid crystal element to exhibit a low pretilt angle of, for example, 1 degree or less (hereinafter, also referred to as "low pretilt angle characteristics") in the rubbing alignment film, R is²Preferably an alkyl group having 1 to 5 carbon atoms or a releasable group, more preferably a releasable group, and particularly preferably a t-butoxycarbonyl group.

With respect to R³Examples of the halogen atom include: fluorine atom, chlorine atom, bromine atom, iodine atom, etc. From the viewpoint of improving the liquid crystal alignment properties of the obtained liquid crystal element, m is preferably 0 to 2, more preferably 0 or 1, and even more preferably 0.

From the viewpoint of achieving high VHR, high reliability and excellent liquid crystal alignment of the liquid crystal element, B¹The aromatic ring (b) is preferably a benzene ring or a pyridine ring, and more preferably a benzene ring.

The partial structure (A) is preferably a partial structure represented by the formula (1-1) or R in the formula (1-2) from the viewpoint of obtaining a liquid crystal element exhibiting good liquid crystal alignment properties and low pretilt angle characteristics²A monovalent hydrocarbon group having 1 to 10 carbon atoms or a releasable group, and more preferably a partial structure represented by the formula (1-1).

B in the formulae (1-1) and (1-2)¹When the phenyl ring is substituted or unsubstituted, the partial structure (A) may be represented by the following formula (1-1A) or the following formula (1-2A).

[ solution 3]

(in the formulae (1-1A) and (1-2A), R^1aIs a divalent chain hydrocarbon group having 1 or more carbon atoms or a chain hydrocarbon group having 2 or more carbon atoms, and any methylene group is bonded to-O-, -S-, -CO-, -COO-, -NR under non-adjacent conditions⁴-、-CO-NR⁴-、-NR⁴-CO-O-or-NR⁴-CO-NR⁵A divalent radical derived from substitution. m is an integer of 0 to 3. R²And R³The same meanings as in the above formulae (1-1) and (1-2). In the case where m is 2 or 3, a plurality of R in the formula³Are the same group or different groups from each other. "" indicates a bond. )

The method for producing the polymer [ P ] is not particularly limited as long as the partial structure (A) can be introduced into the main chain. In terms of ease of introducing the partial structure (A) into the main chain, the polymer [ P ] is preferably produced by a method of polymerizing a monomer having the partial structure (A). The monomer having the partial structure (a) is preferably a diamine compound (hereinafter also referred to as "specific diamine") having the partial structure (a) in terms of the ability to form a liquid crystal alignment film having high affinity for liquid crystal and high mechanical strength and the high degree of freedom in selection of the monomer.

The "main chain" of the polymer means a part of the "backbone" including the longest atomic chain in the polymer. Furthermore, it is permissible for the "backbone" portion to comprise a loop structure. That is, the phrase "having the partial structure (A) in the main chain" means that the partial structure (A) constitutes a part of the main chain. By "side chain" of a polymer is meant a moiety that branches from the "backbone" of the polymer.

The specific diamine is not particularly limited as long as it is a monomer having a partial structure (a) and two primary amino groups, and the structure of the other portion is not particularly limited. Preferable specific examples of the specific diamine include a compound represented by the following formula (2-1) and a compound represented by the following formula (2-2). The polymer [ P ] preferably has a structural unit derived from at least one selected from the group consisting of a compound represented by the following formula (2-1) and a compound represented by the following formula (2-2).

[ solution 4]

(formula (2-1) and formula (2-2) wherein A¹Is a single bond, a divalent alicyclic group, a divalent aromatic ring group, a divalent group represented by the following formula (3-1), or a divalent group represented by the following formula (3-2). B is¹、R¹、R¹And R³The same meanings as in the above formulae (1-1) and (1-2). Wherein, in A¹In the case of a single bond, R¹The carbon atom constituting the hydrocarbon group is bonded to the primary amino group in the formula. )

[ solution 5]

(in the formulae (3-1) and (3-2), B²Is a substituted or unsubstituted aromatic ring, and forms a condensed ring structure with the nitrogen-containing heterocyclic ring in the formula (3-1) and the formula (3-2). R⁶Is a monovalent organic group. R is⁷Is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms. ". x 1" represents a bond to the primary amino group in formula (2-1) or formula (2-2). "" indicates a bond. )

In the above formulae (2-1) and (2-2), A is¹Examples of the divalent alicyclic group in (b) include groups obtained by removing two hydrogen atoms from an alicyclic hydrocarbon ring such as a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, or a cycloheptane ring. In A¹In the case of a divalent alicyclic group, a substituent may be introduced into the ring portion of the alicyclic hydrocarbon ring. As the substituent, there may be mentioned: c1-5 alkyl groupAn alkoxy group having 1 to 5 carbon atoms, a halogen atom, etc.

As A¹The divalent aromatic ring group of (2) includes a divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group. A. the¹The divalent aromatic ring group of (2) is preferably a divalent aromatic hydrocarbon group or a divalent nitrogen-containing aromatic heterocyclic group. A. the¹The aromatic ring moiety may have a substituent. As the substituent, there may be mentioned: alkyl group having 1 to 5 carbon atoms, alkoxy group having 1 to 5 carbon atoms, halogen atom, etc.

As A¹Specific examples of the divalent aromatic cyclic group include a divalent aromatic cyclic group in which two hydrogen atoms are removed from any hydrogen atom bonded to a carbon atom constituting a benzene ring, a biphenyl ring, a naphthalene ring or an anthracene ring; examples of the divalent nitrogen-containing aromatic heterocyclic group include groups obtained by removing two of any hydrogen atoms bonded to carbon atoms constituting a pyridine ring, a pyrimidine ring, a pyridazine ring, or a pyrazine ring.

From the viewpoint of achieving high density of the liquid crystal alignment film, A¹The divalent aromatic ring group of (b) is preferably a substituted or unsubstituted phenylene group, biphenylene group or pyridyldiyl group, and more preferably a substituted or unsubstituted phenylene group.

In the formulae (3-1) and (3-2), with respect to R⁶、R⁷As specific examples and preferred examples of (3), R in the above-mentioned formula (2-1) and formula (2-2) can be cited respectively²、R³And (4) description. With respect to B²As specific examples and preferred examples of (3), B in the above-mentioned formula (2-1) and formula (2-2) can be applied¹And (4) description.

In the above-mentioned formulae (2-1) and (2-2), the position of the primary amino group bonded to a condensed ring structure formed by condensation of an aromatic ring and an imidazole ring (hereinafter, also referred to as "specific condensed ring structure") is not particularly limited. In the case where the specific condensed ring structure is a benzimidazole structure, the bonding position of the primary amino group in the benzimidazole structure is preferably at the 5-position or the 6-position. The specific diamine used for synthesizing the polymer [ P ] may contain a positional isomer having a different position from the primary amino group bonded to the specific condensed ring structure.

From the viewpoint of obtaining a highly reliable liquid crystal element with little decrease in Voltage Holding Ratio (VHR) even when driven for a long time, and from the viewpoint of obtaining a liquid crystal element exhibiting good liquid crystal alignment properties, a¹Preferably a divalent alicyclic group, a divalent aromatic ring group, a divalent group represented by the formula (3-1) or a divalent group represented by the formula (3-2), more preferably a divalent aromatic ring group, a divalent group represented by the formula (3-1) or a divalent group represented by the formula (3-2).

Among them, the specific diamine is preferably at least one selected from the group consisting of a compound represented by the following formula (2-1A) and a compound represented by the following formula (2-2A).

[ solution 6]

(formula (2-1A) and formula (2-2A) wherein A^1aA single bond, a divalent alicyclic group, a divalent aromatic ring group, a divalent group represented by the following formula (3-1A), or a divalent group represented by the following formula (3-2A). R^1aAnd m is the same as the above formula (1-1A) and formula (1-2A). R²And R³The same as the above formula (1-1) and formula (1-2). )

[ solution 7]

(in the formulae (3-1A) to (3-2A), R is an integer of 0 to 3. R⁶And R⁷The same as the above formula (3-1) and formula (3-2). In the case where R is 2 or 3, a plurality of R in the formula⁷Are the same group or different groups from each other. ". x 1" represents a bond to the primary amino group in formula (2-1A) or formula (2-2A). "" indicates a bond. )

Among the above, the specific diamine is preferably selected from the compounds represented by the formula (2-1A)And R in the formula (2-2A)²At least one member selected from the group consisting of C1-10 monovalent hydrocarbon groups and leaving group compounds, and more preferably a compound represented by the formula (2-1A). Further, regarding the compound represented by the formula (2-1A), in the formula (2-1A), A^1aPreferably a divalent group represented by the formula (3-1A), phenylene group, biphenylene group or pyridyldiyl group, more preferably a divalent group represented by the formula (3-1A).

Specific examples of the specific diamine include compounds represented by the following formulae (4-1) to (4-34).

[ solution 8]

[ solution 9]

[ solution 10]

[ solution 11]

[ solution 12]

[ solution 13]

In the polymer [ P ], from the viewpoint of obtaining a liquid crystal element which exhibits good liquid crystal alignment properties and low pretilt angle characteristics and which exhibits high VHR and high reliability, the content ratio of the structural unit derived from the monomer having the partial structure (a) (hereinafter also referred to as "structural unit (a)") is preferably 2 parts by mole or more with respect to 100 parts by mole of the total amount of the monomer units of the polymer [ P ]. The content ratio of the structural unit (a) is more preferably 5 parts by mole or more, and still more preferably 7 parts by mole or more, relative to 100 parts by mole of the total amount of the monomer units of the polymer [ P ]. The content of the structural unit (A) may be appropriately set according to the main chain of the polymer [ P ], but is, for example, 50 parts by mole or less based on 100 parts by mole of the total amount of the monomer units of the polymer [ P ]. The constituent unit (A) of the polymer [ P ] may be only one type, or two or more types.

With respect to polymers [ P ]

The main chain of the polymer [ P ] is not particularly limited. Among them, the polymer [ P ] is preferably at least one selected from the group consisting of polyamic acids, polyamic acid esters, and polyimides, in terms of being capable of forming a liquid crystal alignment film having high affinity for liquid crystals, high mechanical strength, and high reliability.

(Polyamic acid)

In the case where the polymer [ P ] is a polyamic acid, the polyamic acid (hereinafter also referred to as "polyamic acid [ P ]") can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound containing a specific diamine.

(Tetracarboxylic acid dianhydride)

Examples of tetracarboxylic acid dianhydride used for synthesizing polyamic acid [ P ] include: aliphatic tetracarboxylic acid dianhydride, alicyclic tetracarboxylic acid dianhydride, aromatic tetracarboxylic acid dianhydride, and the like. Specific examples thereof include 1,2,3, 4-butanetetracarboxylic dianhydride, ethylenediaminetetraacetic dianhydride and the like; examples of the alicyclic tetracarboxylic dianhydride include: 1,2,3, 4-cyclobutanetetracarboxylic dianhydride, 1, 3-dimethyl-1, 2,3, 4-cyclobutanetetracarboxylic dianhydride, 2,3, 5-tricarboxycyclopentylacetic dianhydride, 5- (2, 5-dioxotetrahydrofuran-3-yl) -3a,4,5,9 b-tetrahydronaphtho [1,2-c ] furan-1, 3-dione, 5- (2, 5-dioxotetrahydrofuran-3-yl) -8-methyl-3 a,4,5,9 b-tetrahydronaphtho [1,2-c ] furan-1, 3-dione, 2,4,6, 8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride, cyclopentanetetracarboxylic dianhydride, Cyclohexane tetracarboxylic dianhydride, 3,5, 6-tricarboxyl-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, and the like; examples of the aromatic tetracarboxylic acid dianhydride include pyromellitic dianhydride, 4,4'- (hexafluoroisopropylidene) diphthalic anhydride, ethylene glycol bistrimellitic anhydride ester, 4,4' -carbonyldiphthalic anhydride, and 3,3',4,4' -biphenyltetracarboxylic acid dianhydride, and in addition, tetracarboxylic acid dianhydrides described in japanese patent application laid-open No. 2010-97188 can be used. As the tetracarboxylic dianhydride, one species may be used alone or two or more species may be used in combination.

The tetracarboxylic dianhydride used for synthesizing the polyamic acid [ P ] preferably contains at least one selected from the group consisting of an aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride, and more preferably contains an alicyclic tetracarboxylic dianhydride, in order to obtain a liquid crystal alignment film having high solubility and exhibiting good liquid crystal alignment properties and electrical characteristics. The proportion of the alicyclic tetracarboxylic dianhydride used is preferably 20 mol% or more, more preferably 40 mol% or more, and still more preferably 50 mol% or more, based on the total amount of the tetracarboxylic dianhydride used for synthesizing the polyamic acid [ P ].

(diamine Compound)

The diamine compound used for the synthesis of the polyamic acid [ P ] may be only the specific diamine, or may include both the specific diamine and a diamine not having the partial structure (a) (hereinafter, also referred to as "other diamine"). As other diamines, mention may be made of: aliphatic diamines, alicyclic diamines, aromatic diamines, diaminoorganosiloxanes, and the like.

Specific examples of the other diamines include m-xylylenediamine and hexamethylenediamine; examples of the alicyclic diamine include 1, 4-diaminocyclohexane, 4' -methylenebis (cyclohexylamine), and the like; as the aromatic diamine, p-phenylenediamine, 4 '-diaminodiphenylmethane, 4' -diaminodiphenylethane, 4-aminophenyl-4-aminobenzoate, 4 '-diaminoazobenzene, 3, 5-diaminobenzoic acid, 1, 5-bis (4-aminophenoxy) pentane, 1, 2-bis (4-aminophenoxy) ethane, 1, 3-bis (4-aminophenoxy) propane, 1, 6-bis (4-aminophenoxy) hexane, 6' - (pentamethylenedioxy) bis (3-aminopyridine), N '-bis (5-amino-2-pyridyl) -N, N' -di (tert-butoxycarbonyl) ethylenediamine, bis [2- (4-aminophenyl) ethyl ] adipic acid, bis (4-aminophenyl) ethyl ] hexanediamine, bis (4-aminophenyl) ethyl) pentanediamine, bis (4-aminophenoxy) ethane, 1, 2-bis (4-aminophenoxy) ethane, 1, 6-bis (4-aminophenoxy) propane, 6 '-pentamethylenedioxy) ethane, bis (3-aminopyridine), N' -bis (tert-butoxycarbonyl) ethane, bis (4-amino-2-amino-2-pyridyl) hexane, bis (4-amino-phenoxyethyl) hexane, bis (4-aminoxy) hexane, bis (4-amino-phenyl) hexane, bis (4-amino-2, bis (4-amino-2-phenyl) hexane, bis (4-amino) hexane, bis (2-bis (4-amino) hexane, bis (4-phenyl) hexane, bis (4-amino) hexane, bis (2-bis (2, bis (4-amino) hexane, bis (2, bis (p-amino) hexane, bis (p-2, bis (p-, 4,4' -diaminodiphenyl ether, 4' -diaminodiphenylamine, 4' -diaminodiphenylethylurea, 2-bis [4- (4-aminophenoxy) phenyl ] propane, 2-bis (4-aminophenyl) hexafluoropropane, 1, 4-bis (4-aminophenoxy) benzene, 4' -bis (4-aminophenoxy) biphenyl, 2' -dimethyl-4, 4' -diaminobiphenyl, 4' - (phenylenediisopropylidene) dianiline, 2, 6-diaminopyridine, 2, 4-diaminopyrimidine, 3, 6-diaminocarbazole, N-methyl-3, 6-diaminocarbazole, 3, 6-diaminoacridine, diphenylamine structure-containing monomer, and the like, The following formula (D-1)

[ solution 14]

(in the formula (D-1), R¹¹And R¹²Each independently is an alkanediyl group. R¹³Is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a protecting group. n1 is an integer of 1 to 3. In the case where n1 is 2 or 3, plural R' s¹²Are the same or different radicals from each other, a plurality of R¹³Are the same group or different groups from each other. )

Main chain type diamines such as the compounds represented by the above;

hexadecyloxy-2, 4-diaminobenzene, octadecyloxy-2, 5-diaminobenzene, cholestanyloxy-3, 5-diaminobenzene, cholesteryloxy-3, 5-diaminobenzene, cholestanyloxy-2, 4-diaminobenzene, cholesteryloxy-2, 4-diaminobenzene, cholesteryl ester of 3, 5-diaminobenzoic acid, lanostanyl ester of 3, 5-diaminobenzoic acid, 3, 6-bis (4-aminobenzoyloxy) cholestane, 3, 6-bis (4-aminophenoxy) cholestane, 4- (4' -trifluoromethoxybenzoyloxy) cyclohexyl-3, 5-diaminobenzoate, 1-bis (4- ((aminophenyl) methyl) phenyl) -4-butylcyclohexane, 3, 5-diaminobenzoic acid ═ 5 ξ -cholestan-3-yl, the following formula (E-1)

[ solution 15]

(in the formula (E-1), X^IAnd X^IIEach independently represents a single bond, -O-, -COO-or-OCO- (wherein "" represents the same as X)^IA bond of (2). ). R^IAn alkanediyl group having 1 to 3 carbon atoms. R^IIIs a single bond or an alkanediyl group having 1 to 3 carbon atoms. R is^IIIIs alkyl, alkoxy, fluoroalkyl or fluoroalkoxy having 1-20 carbon atoms. a is 0 or 1. b is an integer of 0 to 3. c is an integer of 0 to 2. d is 0 or 1. Wherein 1 ≦ a + b + c ≦ 3. )

Side chain type diamines such as the compounds shown,

examples of the diaminoorganosiloxane include 1, 3-bis (3-aminopropyl) -tetramethyldisiloxane.

Examples of the compound represented by the formula (D-1) include compounds represented by the following formulae (D-1-1) to (D-1-3). Examples of the compound represented by the formula (E-1) include compounds represented by the following formulae (E-1-1) to (E-1-4). As the other diamine, one kind may be used alone or two or more kinds may be used in combination. In the formula, "Boc" represents a tert-butoxycarbonyl group (the same applies hereinafter).

[ solution 16]

In synthesizing the polyamic acid [ P ], the ratio of the specific diamine to be used is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, based on the total amount of the diamine compound used in the synthesis of the polyamic acid [ P ], from the viewpoint of obtaining a liquid crystal element which exhibits good liquid crystal alignment properties and a low pretilt angle and exhibits a high VHR and high reliability. One of the specific diamines may be used alone, or two or more of them may be used in combination.

(Synthesis of Polyamic acid)

The polyamic acid [ P ] can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound, optionally together with a molecular weight modifier. In the synthesis reaction of the polyamic acid [ P ], the tetracarboxylic dianhydride and the diamine compound are preferably used in a ratio of 0.2 to 2 equivalents of acid anhydride groups of the tetracarboxylic dianhydride to 1 equivalent of amino groups of the diamine compound. Examples of the molecular weight modifier include: and acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride, monoamine compounds such as aniline, cyclohexylamine, and n-butylamine, and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The use ratio of the molecular weight modifier is preferably 20 parts by mass or less with respect to 100 parts by mass of the total of the tetracarboxylic dianhydride and the diamine compound used.

The synthesis reaction of the polyamic acid [ P ] is preferably carried out in an organic solvent. The reaction temperature in this case is preferably-20 ℃ to 150 ℃ and the reaction time is preferably 0.1 hour to 24 hours. Examples of the organic solvent used in the reaction include: aprotic polar solvent, phenol solvent, alcohol solvent, ketone solvent, ester solvent, ether solvent, halogenated hydrocarbon, etc. Among them, it is preferable to use one or more selected from the group consisting of N-methyl-2-pyrrolidone, N-dimethylacetamide, N-dimethylformamide, dimethyl sulfoxide, γ -butyrolactone, tetramethylurea, hexamethylphosphoric triamide, m-cresol, xylenol, and halogenated phenol as a reaction solvent, or to use a mixture of one or more of these and another organic solvent (e.g., butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount of the organic solvent used is preferably 0.1 to 50% by mass of the total amount of the tetracarboxylic dianhydride and the diamine relative to the total amount of the reaction solution.

Thus, a polymer solution in which the polyamic acid [ P ] is dissolved was obtained. The polymer solution may be directly used for the preparation of the liquid crystal aligning agent, or may be used for the preparation of the liquid crystal aligning agent after the polyamic acid [ P ] contained in the polymer solution is separated.

Polyamic acid ester

In the case where the polymer [ P ] is a polyamic acid ester, the polyamic acid ester (hereinafter also referred to as "polyamic acid ester [ P ]") can be obtained, for example, by the following method or the like: [I] a method of reacting the polyamic acid [ P ] with an esterifying agent; [ II ] a method of reacting a tetracarboxylic acid diester with a diamine compound containing a specific diamine; [ III ] A method for reacting a tetracarboxylic acid diester dihalide with a diamine compound containing a specific diamine. The polyamic acid ester [ P ] may have only an amic acid ester structure or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist. The reaction solution obtained by dissolving the polyamic acid ester [ P ] may be used as it is for the production of the liquid crystal aligning agent, or may be used for the production of the liquid crystal aligning agent after the polyamic acid ester [ P ] contained in the reaction solution is separated.

Polyimide (II)

In the case where the polymer [ P ] is a polyimide, the polyimide (hereinafter also referred to as "polyimide [ P") can be obtained, for example, by subjecting the polyamic acid [ P ] synthesized in the above manner to dehydrative ring closure and imidization. The polyimide [ P ] may be a completely imidized product obtained by dehydration ring closure of all the amic acid structures of the polyamic acid [ P ] which is a precursor thereof, or may be a partially imidized product obtained by dehydration ring closure of only a part of the amic acid structures so that the amic acid structures and the imide ring structures coexist. The polyimide [ P ] preferably has an imidization ratio of 20 to 99%, more preferably 30 to 90%. The imidization ratio is a percentage representing a ratio of the number of imide ring structures to the total of the number of amic acid structures and the number of imide ring structures of the polyimide. Here, a part of the imide ring may be an imide ring.

The dehydration ring-closure of the polyamic acid [ P ] is preferably carried out by a method comprising dissolving the polyamic acid [ P ] in an organic solvent, adding a dehydrating agent and a dehydration ring-closure catalyst to the solution, and optionally heating the solution. In the above method, as the dehydrating agent, for example, an acid anhydride such as acetic anhydride, propionic anhydride, trifluoroacetic anhydride or the like can be used. The amount of the dehydrating agent to be used is preferably 0.01 to 20 moles based on 1 mole of the amic acid structure of the polyamic acid [ P ]. As the dehydration ring-closure catalyst, for example, pyridine, collidine, lutidine, triethylamine and other tertiary amines can be used. The amount of the dehydration ring-closing catalyst to be used is preferably 0.01 to 10 mol based on 1 mol of the dehydrating agent to be used. The organic solvent used in the dehydration ring-closure reaction may be an organic solvent exemplified as the organic solvent used in the synthesis of polyamic acid [ P ]. The reaction temperature of the dehydration ring-closure reaction is preferably 0 ℃ to 180 ℃. The reaction time is preferably 1.0 to 120 hours. Further, the reaction solution containing the polyimide [ P ] may be directly used for the preparation of the liquid crystal aligning agent, or may be used for the preparation of the liquid crystal aligning agent after the polyimide [ P ] is separated.

The solution viscosity of the polymer [ P ] is preferably 10 to 800 mPas, more preferably 15 to 500 mPas when it is a solution having a concentration of 10% by mass. The solution viscosity (mPas) is a value measured at 25 ℃ with an E-type rotational viscometer using a 10 mass% polymer solution prepared using a good solvent for the polymer [ P ] (e.g., γ -butyrolactone, N-methyl-2-pyrrolidone, etc.).

The polymer [ P ] preferably has a weight average molecular weight (Mw) of 1,000 to 500,000 in terms of polystyrene, as measured by Gel Permeation Chromatography (GPC), more preferably 2,000 to 300,000. The molecular weight distribution (Mw/Mn) represented by the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 7 or less, and more preferably 5 or less. In addition, in the preparation of liquid crystal aligning agent, as the polymer [ P ], can be used alone, can also be two or more combined use.

< other ingredients >

The liquid crystal aligning agent may contain a component different from the polymer [ P ] (hereinafter, also referred to as "other component") in addition to the polymer [ P ].

Polymers [ Q ]

The liquid crystal aligning agent of the present disclosure may further contain a polymer not having the partial structure (a) (hereinafter also referred to as polymer [ Q ]) as a polymer component. The main skeleton of the polymer [ Q ] is not particularly limited. Examples of the polymer [ Q ] include: polyamic acids, polyamic acid esters, polyimides, polyorganosiloxanes, polyesters, polyvinylamines, polyureas, polyamides, polyamideimides, polybenzoxazole precursors, polybenzoxazoles, cellulose derivatives, polyacetals, (meth) acrylic polymers, styrene polymers, maleimide polymers, styrene-maleimide copolymers, and the like. Among them, from the viewpoint of obtaining a highly reliable liquid crystal element, the polymer [ Q ] is preferably at least one selected from the group consisting of polyamic acids, polyamic acid esters, polyimides, polyorganosiloxanes, and polymers containing structural units derived from monomers having polymerizable unsaturated carbon-carbon bonds. Examples of the polymer containing a structural unit derived from a monomer having a polymerizable unsaturated carbon-carbon bond include a (meth) acrylic polymer, a styrene polymer, a maleimide polymer, and a styrene-maleimide copolymer.

When the polymer [ Q ] is contained in the liquid crystal aligning agent, the content ratio of the polymer [ Q ] is preferably 1% by mass or more, more preferably 2% by mass or more, relative to the total amount of the polymer [ P ] and the polymer [ Q ]. The content ratio of the polymer [ Q ] is preferably 95% by mass or less, more preferably 90% by mass or less, relative to the total amount of the polymer [ P ] and the polymer [ Q ]. The polymer [ Q ] may be used singly or in combination of two or more.

Solvent(s)

The liquid crystal aligning agent of the present disclosure is prepared in the form of a liquid composition in which the polymer [ P ] and other components used as needed are preferably dispersed or dissolved in an appropriate solvent.

As the solvent, an organic solvent is preferably used. Specific examples thereof include: n-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1, 2-dimethyl-2-imidazolidinone, 1, 3-dimethyl-2-imidazolidinone, phenol, gamma-butyrolactone, gamma-butyrolactam, N-dimethylformamide, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, 1-hexanol, 2-hexanol, propane-1, 2-diol, 3-methoxy-1-butanol, ethylene glycol monomethyl ether, methyl lactate, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl propionate, methyl methoxypropionate, methyl propionate, ethyl propionate, methyl propionate, ethyl propionate, methyl propionate, ethyl acetate, ethyl propionate, ethyl acetate, ethyl propionate, ethyl acetate, ethyl propionate, ethyl acetate, ethyl, Ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-isopropyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisoamyl ether, ethylene carbonate, Propylene Glycol Monomethyl Ether (PGME), diethylene glycol diethyl ether acetate, Propylene Glycol Monomethyl Ether Acetate (PGMEA), propylene glycol diacetate, cyclopentane, cyclohexane, and the like. The solvent may be used singly or in combination of two or more.

Examples of the other components contained in the liquid crystal aligning agent include, in addition to the above components: crosslinking agents, antioxidants, metal chelate compounds, hardening accelerators, surfactants, fillers, dispersants, photosensitizers, and the like. The blending ratio of the other components may be appropriately selected depending on each compound within a range not impairing the effects of the present disclosure.

The concentration of the solid component in the liquid crystal aligning agent (the ratio of the total mass of the components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, and the like, and is preferably in the range of 1 to 10 mass%. When the solid content concentration is 1 mass% or more, the film thickness of the coating film can be sufficiently ensured, and a liquid crystal alignment film exhibiting more excellent liquid crystal alignment properties can be obtained, which is preferable. On the other hand, when the solid content concentration is 10 mass% or less, the coating film can be made to have an appropriate thickness, a liquid crystal alignment film exhibiting good liquid crystal alignment properties can be easily obtained, and the viscosity of the liquid crystal alignment agent is appropriate, so that the coating properties tend to be good.

Liquid crystal alignment film and liquid crystal element

The liquid crystal alignment film of the present disclosure can be produced by the liquid crystal aligning agent prepared as described above. The liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal aligning agent described above. The driving method of the liquid crystal In the liquid crystal element is not particularly limited, and the liquid crystal can be applied to various modes such as a Twisted Nematic (TN) mode, a Super Twisted Nematic (STN) mode, a Vertical Alignment (VA) mode (including a Vertical Alignment-Multi-domain Vertical Alignment (VA-MVA) mode, a Vertical Alignment-Patterned Vertical Alignment (VA-PVA) mode, etc.), an In-Plane Switching (IPS) mode, an edge Field Switching (FFS) mode, an optically compensated bend (optically compensated bend, OCB) mode, a Polymer stabilized Alignment (Polymer Alignment, PSA), and the like. The liquid crystal element can be manufactured by a method including, for example, the following steps 1 to 3. In step 1, different substrates are used depending on the desired operation mode. The steps 2 and 3 are common to the respective operation modes.

< step 1: formation of coating film >

First, a liquid crystal aligning agent is applied to a substrate, and preferably, the applied surface is heated to form a coating film on the substrate. As the substrate, for example: float glass, soda glass, and the like; transparent substrates comprising plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly (alicyclic olefin). As the transparent conductive film provided on one surface of the substrate, a transparent conductive film containing tin oxide (SnO) can be used₂) A film of (Nesa) (registered trademark of PPG Corp., USA) containing indium oxide-tin oxide (In)₂O₃-SnO₂) An Indium Tin Oxide (ITO) film of (a). In the case of manufacturing a TN type, STN type, VA type, or PSA type liquid crystal cell, two substrates provided with a patterned transparent conductive film are used. On the other hand, in the case of manufacturing an IPS-type or FFS-type liquid crystal element, a substrate provided with electrodes patterned in a comb-like shape and an opposing substrate provided with no electrodes are used.

The method for applying the liquid crystal aligning agent to the substrate is not particularly limited. The liquid crystal alignment agent can be applied to the substrate by, for example, a spin coating method, a printing method (e.g., an offset printing method, a flexographic printing method, etc.), an ink jet method, a slit coating method, a bar coating method, an extrusion die (extrusion die) method, a direct gravure coater (direct gravure coater) method, a chamber knife coater (chamber coater) method, an offset gravure coater method, an immersion coater method, an MB coater method, or the like.

After the liquid crystal aligning agent is applied, preheating (prebaking) is preferably performed for the purpose of preventing sagging of the applied liquid crystal aligning agent and the like. The pre-baking temperature is preferably 30-200 ℃, and the pre-baking time is preferably 0.25-10 minutes. Thereafter, the solvent is completely removed, and a calcination (post-baking) step is performed for the purpose of thermal imidization of the amic acid structure present in the polymer, if necessary. The calcination temperature (post-baking temperature) in this case is preferably 80 to 280 ℃, more preferably 80 to 250 ℃. The post-baking time is preferably 5 minutes to 200 minutes. The film thickness of the formed film is preferably 0.001 to 1 μm.

< step 2: orientation treatment

In the case of producing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal cell, the coating film formed in the above-described step 1 is subjected to a treatment (alignment treatment) for imparting liquid crystal alignment ability. Thereby, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film. As the alignment treatment, rubbing treatment in which the surface of a coating film formed on a substrate is wiped with cotton, nylon, or the like, or photo-alignment treatment in which the coating film is irradiated with light to impart liquid crystal alignment ability to the coating film is preferably used. In the case of producing a vertical alignment type liquid crystal device, the coating film formed in the step 1 may be used as it is as a liquid crystal alignment film, and the coating film may be subjected to an alignment treatment in order to further improve the liquid crystal alignment ability. The liquid crystal alignment film preferred for the liquid crystal cell of the vertical alignment type can also be preferably used for the liquid crystal cell of the PSA type.

Light irradiation for photo-alignment can be performed by the following method or the like: a method of irradiating the coating film after the post-baking step; a method of irradiating a coating film after the pre-baking step and before the post-baking step; a method of irradiating the coating film during heating of the coating film in at least one of the pre-baking step and the post-baking step. As the radiation irradiated to the coating film, for example, ultraviolet rays and visible rays including light having a wavelength of 150nm to 800nm can be used. Preferably, the ultraviolet light contains light having a wavelength of 200nm to 400 nm. When the radiation is polarized light, the radiation may be linearly polarized light or partially polarized light. When the radiation used is linearly polarized light or partially polarized light, the irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these directions. The irradiation direction in the case of unpolarized radiation is an oblique direction.

Examples of the light source used include: low pressure mercury lamps, high pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, excimer lasers, and the like. The irradiation dose of the radiation is preferably 200J/m²～30,000J/m²More preferably 500J/m²～10,000J/m². After the light irradiation for imparting alignment ability, the substrate surface may be subjected to a cleaning treatment using, for example, water, an organic solvent (for example, methanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, or the like), or a mixture thereof, or a heating treatment of the substrate.

< step 3: construction of liquid Crystal cell

Two substrates on which liquid crystal alignment films are formed in this manner are prepared, and liquid crystal is disposed between the two substrates disposed opposite to each other, thereby manufacturing a liquid crystal cell. In the production of a liquid crystal cell, for example, the following methods can be mentioned: a method of disposing two substrates so as to face each other with a gap therebetween with liquid crystal alignment films therebetween, bonding peripheral portions of the two substrates together with a sealant, filling a cell gap surrounded by the substrate surfaces and the sealant with a filling liquid crystal, and closing the filling hole, and a method of using an ODF (one drop fill) method. As the sealant, for example, an epoxy resin containing a curing agent and alumina balls as spacers can be used. The liquid crystal includes nematic liquid crystal and smectic liquid crystal, and among them, nematic liquid crystal is preferable.

In the PSA mode, the following processes are performed: a polymerizable compound (for example, a polyfunctional (meth) acrylate compound or the like) is filled in the cell gap together with the liquid crystal, and after the liquid crystal cell is constructed, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates. In the production of a PSA-type liquid crystal device, the polymerizable compound is used in an amount of, for example, 0.01 to 3 parts by mass, preferably 0.05 to 1 part by mass, based on 100 parts by mass of the total liquid crystal.

In the case of manufacturing a liquid crystal display device, a polarizing plate is subsequently bonded to the outer surface of the liquid crystal cell. Examples of the polarizing plate include a polarizing plate in which a polarizing film called an "H film" in which iodine is absorbed while polyvinyl alcohol is stretched and oriented, is sandwiched between cellulose acetate protective films, and a polarizing plate including the H film itself.

The liquid crystal element of the present disclosure can be effectively applied to various uses. Specifically, the present invention can be used as various display devices, light control devices, phase difference films, and the like, for example, for watches, portable game machines, word processors (word processors), notebook Personal computers, car navigation systems (car navigation systems), video cameras (camcorders), Personal Digital Assistants (PDAs), Digital cameras (Digital cameras), cellular phones, smart phones, various monitors, liquid crystal televisions, information displays, and the like.

[ examples ]

The embodiments are described in more detail below with reference to examples, but the present invention is not to be construed as being limited to the examples below.

In the following examples, the weight average molecular weight Mw and the number average molecular weight Mn of the styrene-maleimide copolymer, and the imidization ratio of polyimide in the polymer solution were measured by the following methods. The required amounts of the raw material compounds and the polymer used in the following examples were secured by repeating the synthesis on the synthesis scale shown in the following synthesis examples as necessary.

[ weight-average molecular weight Mw and number-average molecular weight Mn ]

Mw and Mn are values in terms of polystyrene measured by GPC under the following conditions.

Pipe column: TSKgelGRCXLII manufactured by Tosoh (Strand, Tosoh)

Solvent: tetrahydrofuran (THF)

Temperature: 40 deg.C

Pressure: 68kgf/cm²

[ imidization ratio of polyimide ]

Putting the polyimide solution into pure water, drying the obtained precipitate at room temperature under reduced pressure, dissolving in deuterated dimethyl sulfoxide, and performing hydrogen nuclear magnetic resonance at room temperature with tetramethylsilane as reference substance¹H-nuclear magnetic resonance，¹H-NMR). According to the obtained¹H-NMR spectrum, the imidization rate [% ] was determined by the following numerical formula (1)]。

Imidization rate [% ]]＝(1-(A¹/(A²×α)))×100…(1)

(in the numerical formula (1), A¹Is the peak area of a proton derived from an NH group appearing in the vicinity of a chemical shift of 10ppm, A²Is the peak area derived from other protons, and α is the number ratio of the other protons to 1 proton of the NH group in the precursor (polyamic acid) of the polymer. )

The compounds are briefly described below. In the following, the compound represented by the formula (X) may be simply referred to as "compound (X)".

(tetracarboxylic dianhydride)

[ solution 17]

(diamine Compound)

[ solution 18]

The compounds (DA-1) to (DA-6) used in the following examples include a compound having a primary amino group at the 5-position of benzimidazole (the compound represented by the above formula) and a positional isomer having a primary amino group at the 6-position of benzimidazole.

[ solution 19]

[ solution 20]

[ solution 21]

(others)

[ solution 22]

[ solution 23]

[ solution 24]

< Synthesis of Polymer >

1. Synthesis of Polyamic acid

[ Synthesis example 1]

100 parts by mole of 1,2,3, 4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 100 parts by mole of 4,4' -diamino-1, 2-diphenylethane as diamine compound were dissolved in N-methyl-2-pyrrolidone (NMP) and reacted at room temperature for 6 hours to obtain a solution containing 15 mass% of polyamic acid (which was referred to as polymer (PA-1)).

Synthesis examples 2 to 28

A solution containing polyamic acid (polymer (PA-2) to polymer (PA-28)) was obtained in the same manner as in synthesis example 1, except that the kinds and amounts of tetracarboxylic dianhydride and diamine compound used were changed as described in tables 1 and 2.

[ Table 1]

[ Table 2]

2. Synthesis of polyimide

[ Synthesis example 29]

100 parts by mole of 1, 3-dimethylcyclobutane-1, 2:3, 4-tetracarboxylic dianhydride as tetracarboxylic dianhydride, 20 parts by mole of compound (DA-4) as a diamine compound and 80 parts by mole of compound (DB-7) were dissolved in NMP and reacted at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamic acid. Then, NMP was added to the obtained polyamic acid solution to prepare a solution having a polyamic acid concentration of 10% by mass, and pyridine and acetic anhydride were added to perform a dehydration ring-closure reaction at 60 ℃ for 4 hours. After the dehydration ring-closure reaction, the solvent in the system was subjected to solvent substitution with fresh NMP to obtain a solution containing 15 mass% of polyimide (polymer (PI-1)) having an imidization rate of about 80%.

[ Synthesis examples 30 to 35]

A solution containing polyimide (polymers (PI-2 to PI-7)) was obtained in the same manner as in Synthesis example 29, except that the kinds and amounts of the tetracarboxylic dianhydride and diamine compound used were changed as described in Table 3.

[ Table 3]

3. Synthesis of polyorganosiloxanes

[ Synthesis example 36]

A1000 mL three-necked flask was charged with 100.0g of 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane (the compound represented by the formula (s-1)), 500g of methyl isobutyl ketone and 10.0g of triethylamine, and mixed at room temperature. Then, 100g of deionized water was added dropwise from the dropping funnel over 30 minutes, and the reaction was carried out at 80 ℃ for 6 hours while mixing under reflux. After the reaction was completed, the organic layer was taken out, washed with a 0.2 mass% ammonium nitrate aqueous solution until the washed water was neutral, and then the solvent and water were distilled off under reduced pressure. Methyl isobutyl ketone was added in an appropriate amount to obtain a 50 mass% solution of a polymer of polyorganosiloxane with an epoxy group (ESSQ-1).

A500 mL three-necked flask was charged with 3.10g of compound (c-1) (20 mol% based on the amount of epoxy group in polymer (ESSQ-1)), 3.24g of compound (c-2) (10 mol% based on the amount of epoxy group in polymer (ESSQ-1)), 1.00g of tetrabutylammonium bromide, 20.0g of a solution containing polymer (ESSQ-1), and 290.0g of methyl isobutyl ketone, and the mixture was stirred at 90 ℃ for 18 hours. After cooling to room temperature, the liquid separation washing operation was repeated 10 times with distilled water. Thereafter, the organic layer was collected, concentrated twice by a rotary evaporator and diluted with NMP, and then adjusted to a solid content concentration of 10 mass% using NMP, to obtain an NMP solution of polyorganosiloxane (which was a polymer (PSQ-1)).

4. Synthesis of styrene-maleimide copolymer

[ Synthesis example 37]

5.00g of compound (M-1), 1.05g of compound (M-2), 4.80g of compound (M-3), 2.26g of compound (M-4), 0.39g of 2,2' -azobis (2, 4-dimethylpentanenitrile) as a radical polymerization initiator, 0.39g of 2, 4-diphenyl-4-methyl-1-pentene as a chain transfer agent, and 52.5mL of N-methyl-2-pyrrolidone (NMP) as a solvent were charged into a 100mL two-necked flask under nitrogen and polymerized at 70 ℃ for 6 hours. After reprecipitation in methanol, the precipitate was filtered and dried under vacuum at room temperature for 8 hours to obtain a styrene-maleimide copolymer (referred to as polymer (MI-1)). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 30000 and the molecular weight distribution Mw/Mn was 2.

[ Synthesis example 38]

In a 100mL two-necked flask, 10 parts by mole of compound (M-5), 10 parts by mole of compound (M-6), 30 parts by mole of compound (M-7), 10 parts by mole of compound (M-8), 20 parts by mole of compound (M-9), 20 parts by mole of compound (M-10), 2 parts by mole of 2,2' -azobis (2, 4-dimethylvaleronitrile) as a radical polymerization initiator, and 50mL of tetrahydrofuran as a solvent were charged under nitrogen and polymerized at 70 ℃ for 6 hours. After reprecipitation in methanol, the precipitate was filtered and dried under vacuum at room temperature for 8 hours to obtain a styrene-maleimide copolymer (referred to as polymer (MI-2)). The weight-average molecular weight Mw, as measured by GPC in terms of polystyrene, was 92700, and the molecular weight distribution Mw/Mn was 4.78.

< preparation and evaluation of liquid Crystal alignment agent >

Example 1: friction FFS type liquid crystal display element

1. Preparation of liquid crystal aligning agent

The polymer (PA-4) solution obtained in synthesis example 4 was diluted with NMP and Butyl Cellosolve (BC) to prepare a solution having a solvent composition of NMP/BC 80/20 (mass ratio) and a solid content concentration of 3.5 mass%. The solution was filtered using a filter having a pore size of 0.2 μm, thereby preparing a liquid crystal aligning agent (AL-1).

2. Manufacture of FFS type liquid crystal cell using rubbing method

A glass substrate (referred to as a first substrate) having a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) laminated in this order on one surface thereof, and a glass substrate (referred to as a second substrate) having no electrode were prepared. Then, a liquid crystal alignment agent (AL-1) was applied to the electrode-formed surface of the first substrate and the single surface of the second substrate using a spinner, and the resultant was heated (prebaked) for 3 minutes using a 110 ℃. Thereafter, the resultant was dried (post-baked) for 30 minutes in an oven at 230 ℃ in which the inside of the oven was replaced with nitrogen, to form a coating film having an average film thickness of 0.08. mu.m. Then, the surface of the coating film was rubbed by a rubbing machine having a roll around which rayon cloth was wound at a roll rotation speed of 1000rpm, a table moving speed of 3cm/sec and a hair penetration length of 0.3 mm. Thereafter, ultrasonic cleaning was performed in ultrapure water for 1 minute, followed by drying in a clean oven at 100 ℃ for 10 minutes, thereby obtaining a pair of substrates having liquid crystal alignment films.

Then, an epoxy resin adhesive containing alumina balls having a diameter of 3.5 μm was applied by screen printing to the pair of substrates having the liquid crystal alignment films, leaving liquid crystal injection ports at the edge of the surface on which the liquid crystal alignment films were formed. Thereafter, the substrates were stacked and pressed, and the adhesive was thermally cured at 150 ℃ for 1 hour. Then, a gap between the pair of substrates is filled with negative type liquid crystal (MLC-6608, manufactured by Merck) from the liquid crystal injection port, and then the liquid crystal injection port is closed with an epoxy adhesive. Further, in order to remove the flow alignment at the time of liquid crystal injection, the liquid crystal cell was manufactured by heating the liquid crystal at 120 ℃ and then gradually cooling the liquid crystal to room temperature. When a pair of substrates is stacked, the rubbing method of the substrates is made antiparallel.

3. Evaluation of liquid Crystal alignment Properties

The liquid crystal cell manufactured in 2. is controlled at 27,000cd/m²The liquid crystal alignment was evaluated from the rate of change in retardation before and after backlight irradiation after leaving the high-brightness backlight for 500 hours. First, retardation was measured for the liquid crystal cell manufactured in the above 2. by using oxkan (Axoscan) manufactured by Optoscience (Optoscience), and the change rate α of retardation before and after backlight irradiation was calculated by the following equation (z-1). The smaller the change rate alpha is, the smaller the change rate alpha isThe better the liquid crystal alignment. The case where the change rate α is 1% or less is "good (o)", the case where the change rate α is more than 1% and 2% or less is "acceptable (Δ)", and the case where the change rate α is more than 2% is "poor (x)".

α＝Δθ/θ1…(z-1)

(in the formula (z-1), Δ θ represents a retardation difference before and after irradiation, and θ 1 represents a retardation value before irradiation.)

As a result, the liquid crystal alignment properties of the examples were evaluated as "ok (Δ)".

4. Evaluation of Low pretilt Angle characteristic

For the liquid crystal cell manufactured in the 2, the value of the tilt angle of the liquid crystal molecules with respect to the substrate surface was measured by a crystal rotation method using He — Ne laser according to a method described in non-patent document "t.j. schiff et al (t.j.scheffer et al)" Applied Journal of Physics (Journal of Applied Physics, j.appl.phys.) at the 19 th page 2013 (vo.19, p.2013) (1980) ", and was taken as the pretilt angle. When the measured value of the pretilt angle is less than 0.75 degrees, "good (o)" is set, when the measured value of the pretilt angle is 0.75 degrees or more and 1.0 degrees or less, "acceptable (Δ)" is set, and when the measured value of the pretilt angle is greater than 1.0 degrees, "poor (x)". As a result, the low pretilt characteristics of the examples were evaluated as "possible (Δ)" (see the "low tilt" item in table 4).

5. Evaluation of initial VHR

The liquid crystal cell produced in 2 above was left to stand in an oven at 60 ℃, and then a Voltage Holding Ratio (VHR) was measured under conditions of 1V and 1670msec using a VHR measuring device "VHR-1" manufactured by Toyo Technica. As evaluation criteria, when VHR is higher than 70%, it is "good (o)", when VHR is 70% or lower and 60% or higher, "acceptable (Δ)", and when VHR is lower than 60%, it is "poor (x)". As a result, the initial VHR of the example was evaluated as "good (. smallcircle)".

Evaluation of VHR reliability

For the liquid crystal cell manufactured in said 2, reliability with respect to the voltage holding ratio was evaluated. The evaluation was performed in the following manner. First, after a voltage of 1V was applied to the liquid crystal cell for 60 microseconds, a voltage holding ratio (VHR1) was measured at 1670 milliseconds after release of the application. Then, the liquid crystal cell was irradiated with a Cold Cathode Fluorescent Lamp (CCFL) for one week at 60 ℃. After cooling, a voltage of 1V was applied to the liquid crystal cell for 60 microseconds, and then a voltage holding ratio (VHR2) was measured 1670 milliseconds after release of application. The measurement apparatus used was a VHR measurement apparatus "VHR-1" manufactured by Toyo Technica, Inc. The rate of change of VHR (Δ VHR) at that time was calculated from the difference between VHR1 and VHR 2(Δ VHR1-VHR2), and VHR reliability was evaluated using Δ VHR. When Δ VHR is less than 15%, it is determined as "good (o)", when Δ VHR is 15% or more and 20% or less, it is determined as "acceptable (Δ)", and when Δ VHR is more than 20%, it is determined as "poor (x)". As a result, the VHR reliability in the example was "good (∘)".

7. Evaluation of film Strength (Friction resistance)

The liquid crystal aligning agent (AL-1) prepared in the above 1. was coated on a glass substrate using a spinner, and heated (pre-baked) for 3 minutes using a hot plate at 110 ℃. Thereafter, the resultant was dried (post-baked) for 30 minutes in an oven at 230 ℃ in which the inside of the oven was replaced with nitrogen to form a coating film having an average film thickness of 0.08 μm, and the haze value of the coating film was measured using a haze meter (hazemeter). Then, the coating film was subjected to rubbing treatment five times using a rubbing machine having a roller around which cotton cloth was wound, at a roller rotation speed of 1000rpm, a table moving speed of 3cm/sec, and a hair penetration length of 0.3 mm. Then, the haze value of the liquid crystal alignment film was measured using a haze meter, and the difference from the haze value before the rubbing treatment (haze change value) was calculated. When the haze value of the film before the rubbing treatment was Hz1 (%), and the haze value of the film after the rubbing treatment was Hz2 (%), the haze change value was represented by the following equation (z-2).

Haze Change value (%) ═ Hz2-Hz1 … (z-2)

The liquid crystal alignment film was evaluated as "good (. smallcircle)" when the haze change value was less than 1.0, as "acceptable (. DELTA)" when the haze change value was 1.0 or more and 1.5 or less, and as "poor (. smallcircle)" when the haze change value was more than 1.5. When the haze change value is 1.5 or less (more preferably less than 1.0), the film has sufficiently high strength and high friction resistance, that is, the mechanical properties of the film are good. As a result, the film strength was evaluated as "good (o)" in the examples.

Examples 2 to 16 and comparative examples 1 to 4

A liquid crystal aligning agent was prepared in the same manner as in example 1, except that the composition of the liquid crystal aligning agent was changed as shown in table 4. Further, using the obtained liquid crystal aligning agent, an FFS type liquid crystal cell was produced by a rubbing method in the same manner as in example 1, and various evaluations were performed. The results are shown in table 4. In example 5 to example 7, example 9 to example 13, and comparative example 3, two kinds of polymers were used as the polymer components. In table 4, the numerical values in the polymer column indicate the blending ratio (parts by mass) of each polymer in terms of solid content with respect to 100 parts by mass of the total amount of the polymer components used in the preparation of the liquid crystal aligning agent.

[ Table 4]

As shown in table 4, the balance of the liquid crystal alignment property, the initial VHR, and the VHR reliability was obtained and the results were good in examples 1 to 16 using the liquid crystal aligning agent containing the polymer [ P ] compared to comparative examples 1 to 4 using the liquid crystal aligning agent not containing the polymer [ P ]. In addition, examples 1 to 16 are also good with respect to the low pretilt angle characteristics and the mechanical properties of the film.

Example 17: optical FFS type liquid crystal display element

1. Preparation of liquid crystal aligning agent

A solution containing 60 parts by mass of the polymer (PA-11) obtained in synthesis example 11 and a solution containing 40 parts by mass of the polymer (PA-24) obtained in synthesis example 24 were mixed and diluted with NMP and BC to prepare a solution having a solvent composition of NMP/BC 80/20 (mass ratio) and a solid content concentration of 3.5 mass%. The solution was filtered using a filter having a pore size of 0.2 μm, thereby preparing a liquid crystal aligning agent (AL-17).

2. Manufacture of FFS type liquid crystal cell using photo-alignment method

The same first substrate and second substrate as in example 1 were prepared. Then, a liquid crystal aligning agent (AL-17) was applied to the electrode formation surface of the first substrate and the surface of one of the second substrates using a spinner, and the substrates were heated (prebaked) for 1 minute using a hot plate at 80 ℃. Thereafter, the resultant was dried (post-baked) for 30 minutes in an oven at 230 ℃ in which the inside of the oven was replaced with nitrogen, to form a coating film having an average film thickness of 0.1. mu.m. The obtained coating film was irradiated with ultraviolet rays of 1,000J/m containing linearly polarized 254nm bright rays from the substrate normal direction using an Hg-Xe lamp²And photo-alignment treatment is performed. The irradiation dose is a value measured by using a light meter which measures with the wavelength of 254nm as a reference. Then, the photo-alignment treated coating film was heated in a clean oven at 230 ℃ for 30 minutes to be heat-treated, thereby forming a liquid crystal alignment film.

Next, an epoxy resin adhesive containing alumina balls having a diameter of 3.5 μm was applied by screen printing to the outer edge of the surface having the liquid crystal alignment film on one of the pair of substrates on which the liquid crystal alignment film was formed. Then, the substrates were laminated and pressure-bonded so that the projection direction of the polarizing axis on the substrate surface was antiparallel to each other at the time of light irradiation, and the adhesive was thermally cured at 150 ℃ for 1 hour. Then, negative type liquid crystal (MLC-6608, manufactured by Merck) was filled between the pair of substrates through the liquid crystal injection port, and then the liquid crystal injection port was closed with an epoxy adhesive to obtain a liquid crystal cell. Further, in order to remove the flow alignment during the liquid crystal injection, the liquid crystal was heated at 120 ℃ and then gradually cooled to room temperature. The UV irradiation amount after post-baking was 100J/m²～10,000J/m²By performing the above-described series of operations while changing the range of (A) to (B), three or more liquid crystal cells having different ultraviolet irradiation amounts were manufactured, and the liquid crystal cell having the exposure amount (optimum exposure amount) showing the best alignment property was used for the following evaluation。

3. Evaluation of

For the liquid crystal cell manufactured in the 2, the liquid crystal alignment property, the initial VHR, and the VHR reliability were evaluated by the same method as in example 1. Further, the film strength was evaluated in the same manner as in example 1 using a liquid crystal aligning agent (AL-17). The evaluation results are shown in table 5.

[ examples 18 to 20]

A liquid crystal aligning agent was prepared in the same manner as in example 17, except that the composition of the liquid crystal aligning agent was changed as shown in table 5. Further, using the obtained liquid crystal aligning agent, an FFS type liquid crystal cell was produced by a photo-alignment method in the same manner as in example 17, and various evaluations were performed. The results are shown in Table 5. In Table 5, the numerical values in the polymer column indicate the blending ratio (parts by mass) of each polymer in terms of solid content with respect to 100 parts by mass of the total amount of the polymer components used in the preparation of the liquid crystal aligning agent.

[ Table 5]

As shown in table 5, in examples 17 to 20 using the liquid crystal aligning agent containing the polymer [ P ], the liquid crystal alignment property, the initial VHR and the VHR reliability were all evaluated well. In examples 17 to 20, the mechanical properties of the film were also good.

Example 21: optical VA type liquid crystal display element

1. Preparation of liquid crystal aligning agent

A solution containing 30 parts by mass of the polymer (MI-1) obtained in synthesis example 37 and 70 parts by mass of the polymer (PA-24) obtained in synthesis example 24 was mixed and diluted with NMP and BC to prepare a solution having a solvent composition of NMP/BC 80/20 (mass ratio) and a solid content concentration of 3.5 mass%. The solution was filtered using a filter having a pore size of 0.2 μm, thereby preparing a liquid crystal aligning agent (AL-21).

2. Manufacture of optical VA type liquid crystal cell

Using a rotatorThe liquid crystal aligning agent (AL-21) prepared in the above was coated on the transparent electrode surface of the glass substrate with a transparent electrode including an ITO film, and prebaked using a hot plate at 80 ℃ for 1 minute. Thereafter, the resultant was heated at 230 ℃ for 1 hour in an oven in which the inside of the oven was replaced with nitrogen gas, thereby forming a coating film having a thickness of 0.1 μm. Then, the surface of the coating film was irradiated with polarized ultraviolet light 1,000J/m containing 313nm bright lines from a direction inclined at 40 ℃ to the substrate normal line using an Hg-Xe lamp and a Glan-Taylor prism (glan-taylor prism)²Thereby imparting orientation capability to the liquid crystal. The same operation was repeated to produce a pair of (two pieces of) substrates having liquid crystal alignment films.

An epoxy resin adhesive containing alumina balls having a diameter of 3.5 μm was applied to the outer periphery of the surface having the liquid crystal alignment film of one of the substrates by screen printing, and then the liquid crystal alignment films of the pair of substrates were opposed to each other, and pressure-bonded so that the optical axes of the ultraviolet rays of the respective substrates were antiparallel to the projection direction of the substrate surfaces, and the adhesive was heat-cured at 150 ℃ for 1 hour. Then, a negative type liquid crystal (MLC-6608, manufactured by Merck) was filled in the gap between the substrates from the liquid crystal injection port, and then the liquid crystal injection port was closed with an epoxy adhesive. Further, in order to remove the flow alignment during the liquid crystal injection, the liquid crystal was heated at 130 ℃ and then gradually cooled to room temperature.

3. Evaluation of

For the liquid crystal cell manufactured in the 2, the liquid crystal alignment property, the initial VHR, and the VHR reliability were evaluated by the same method as in example 1. The evaluation results are shown in table 6.

Comparative example 5

A liquid crystal aligning agent was prepared in the same manner as in example 21, except that the composition of the liquid crystal aligning agent was changed as shown in table 6. Using the obtained liquid crystal aligning agent, an optical VA liquid crystal cell was produced in the same manner as in example 21, and various evaluations were performed. The results are shown in Table 6. In Table 6, the numerical values in the polymer column indicate the blending ratio (parts by mass) of each polymer in terms of solid content, relative to 100 parts by mass of the total amount of the polymer components used in the preparation of the liquid crystal aligning agent.

[ Table 6]

As shown in table 6, in example 21 in which the liquid crystal aligning agent containing the polymer [ P ] was used, the liquid crystal alignment property, the initial VHR, and the VHR reliability were all evaluated well. On the other hand, in comparative example 5 using the liquid crystal aligning agent not containing the polymer [ P ], the initial VHR was evaluated as "ok", and the VHR reliability was evaluated as "poor".

Example 22: PSA type liquid crystal display element

1. Preparation of liquid crystal aligning agent

A solution containing 5 parts by mass of the polymer (PSQ-1) obtained in synthesis example 36 and a solution containing 95 parts by mass of the polymer (PI-6) obtained in synthesis example 34 were mixed and diluted with NMP and BC to prepare a solution having a solvent composition of NMP/BC 50/50 (mass ratio) and a solid content concentration of 3.5 mass%. The solution was filtered using a filter having a pore size of 0.2 μm, thereby preparing a liquid crystal aligning agent (AL-22).

2. Preparation of liquid Crystal composition

A liquid crystal composition LC1 was obtained by adding 5 mass% of a liquid crystalline compound represented by the following formula (L1-1) and 0.3 mass% of a photopolymerizable compound represented by the following formula (L2-1) to 10g of nematic liquid crystal (MLC-6608, Merck).

[ solution 25]

Production of PSA type liquid Crystal cell

The liquid crystal aligning agent (AL-22) prepared above was applied to the transparent electrode surface of the glass substrate having the transparent electrode including the ITO film using a spinner, prebaked with a hot plate at 80 ℃ for 1 minute, and then heated at 200 ℃ for 1 hour in a nitrogen-substituted oven to remove the solvent, thereby forming a coating film (liquid crystal alignment film) having a thickness of 0.08 μm. The coating film was rubbed with a rubbing machine having a roll around which rayon cloth was wound at a roll rotation speed of 400rpm, a table moving speed of 3cm/sec and a fur penetration length of 0.1 mm. Thereafter, ultrasonic cleaning was performed in ultrapure water for 1 minute, followed by drying in a clean oven at 100 ℃ for 10 minutes, thereby obtaining a substrate having a liquid crystal alignment film. The operation was repeated to obtain a pair (two sheets) of substrates having liquid crystal alignment films. The rubbing treatment is a weak rubbing treatment for controlling collapse of the liquid crystal and for the purpose of performing alignment division by a simple method.

An epoxy resin adhesive containing alumina balls having a diameter of 3.5 μm was applied to the outer periphery of the surface having the liquid crystal alignment film of one of the substrates by screen printing, and then the liquid crystal alignment films of the pair of substrates were opposed to each other, stacked and pressure bonded, and heated at 150 ℃ for 1 hour to thermally cure the adhesive. Then, the gap between the substrates was filled with a liquid crystal composition PLC1 from the liquid crystal injection port, and then the liquid crystal injection port was closed with an epoxy adhesive, and further, the liquid crystal was heated at 150 ℃ for 10 minutes and gradually cooled to room temperature in order to remove the flow alignment at the time of liquid crystal injection.

Then, the obtained liquid crystal cell was subjected to liquid crystal driving by applying an alternating current of 10V having a frequency of 60Hz between the electrodes, and irradiated with ultraviolet rays at a rate of 50,000J/m using a metal halide lamp as a light source by an ultraviolet irradiation device²The ultraviolet ray is irradiated at the irradiation dose of (2). The irradiation dose is measured by using a light meter that measures with a wavelength of 365nm as a reference. Thus, a PSA type liquid crystal cell was manufactured.

4. Evaluation of

For the liquid crystal cell manufactured in the above 3, the liquid crystal alignment property, the initial VHR, and the VHR reliability were evaluated by the same method as in example 1. The evaluation results are shown in table 7.

Example 23 and comparative example 6

A liquid crystal aligning agent was prepared in the same manner as in example 22, except that the composition of the liquid crystal aligning agent was changed as shown in table 7. Further, a PSA-type liquid crystal cell was produced using the obtained liquid crystal aligning agent in the same manner as in example 22, and various evaluations were performed. The evaluation results are shown in table 7. In Table 7, the numerical values in the polymer column indicate the blending ratio (parts by mass) of each polymer in terms of solid content with respect to 100 parts by mass of the total amount of the polymer components used in the preparation of the liquid crystal aligning agent.

[ Table 7]

As shown in table 7, in examples 22 and 23 using the liquid crystal aligning agent containing the polymer [ P ], the liquid crystal alignment properties, the initial VHR, and the VHR reliability were all evaluated well. On the other hand, in comparative example 6 using the liquid crystal aligning agent containing no polymer [ P ], the initial VHR was "ok", and the VHR reliability was evaluated as "poor".

From the above results, it is clear that a liquid crystal device having good liquid crystal alignment properties, high voltage holding ratio, and excellent reliability can be obtained by using a liquid crystal aligning agent containing the polymer [ P ].

Claims

1. A liquid crystal aligning agent comprising a polymer [ P ] having a partial structure (A) in the main chain, wherein the partial structure (A) is at least one selected from the group consisting of a partial structure represented by the following formula (1-1) and a partial structure represented by the following formula (1-2),

in the formulae (1-1) and (1-2), B¹Is a substituted or unsubstituted aromatic ring and forms a condensed ring structure with the nitrogen-containing heterocyclic ring in the formula (1-1) and the formula (1-2); r¹To utilize-C (R)¹⁰)(R¹¹)-、-O-、-S-、-CO-、-COO-、-NR⁴-、-CO-NR⁴-、-NR⁴-CO-O-or-NR⁴-CO-NR⁵And a nitrogen atom constituting a condensed ring in the formula (1-1) or constituting the formula (1-2)) A divalent organic group bonded to the carbon atom of the condensed ring in (1); r¹⁰And R¹¹Each independently is a hydrogen atom or an alkyl group; r⁴And R⁵Each independently is a hydrogen atom or a monovalent organic group; r²Is a monovalent organic group; r³Hydrogen atom, halogen atom, alkyl group having 1 to 3 carbon atoms, or alkoxy group having 1 to 3 carbon atoms; "" indicates a bond.

2. The liquid crystal aligning agent according to claim 1, wherein the polymer [ P ] has a structural unit derived from at least one selected from the group consisting of a compound represented by the following formula (2-1) and a compound represented by the following formula (2-2),

in the formulae (2-1) and (2-2), A¹A single bond, a divalent alicyclic group, a divalent aromatic ring group, a divalent group represented by the following formula (3-1), or a divalent group represented by the following formula (3-2); r¹、R²And R³The same as the above formula (1-1) and formula (1-2); wherein, in A¹In the case of a single bond, R¹The carbon atom constituting the hydrocarbon group is bonded to the primary amino group in the formula,

in the formulae (3-1) and (3-2), B²Is a substituted or unsubstituted aromatic ring and forms a condensed ring structure with the nitrogen-containing heterocyclic ring in the formula (3-1) and the formula (3-2); r⁶Is a monovalent organic group; r⁷Hydrogen atom, halogen atom, alkyl group having 1 to 3 carbon atoms, or alkoxy group having 1 to 3 carbon atoms; "x1" represents a bond to the primary amino group in formula (2-1) or formula (2-2); "" indicates a bond.

3. The liquid crystal aligning agent according to claim 1 or 2Wherein, said R¹The main chain has a chain hydrocarbon structure having 1 or more carbon atoms.

4. The liquid crystal aligning agent according to claim 1 or 2, wherein the polymer [ P ] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

5. The liquid crystal aligning agent according to claim 4, wherein the polymer [ P ] has a structural unit derived from an alicyclic tetracarboxylic dianhydride.

6. The liquid crystal aligning agent according to claim 1 or 2, further comprising a polymer [ Q ] having no said partial structure (A).

7. A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of claims 1 to 6.

8. A liquid crystal cell comprising the liquid crystal alignment film according to claim 7.