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

Abstract

To provide a liquid crystal alignment agent that can form a liquid crystal alignment film having excellent liquid crystal alignment properties and also excellent adhesion to a substrate, and can also give a liquid crystal element that does not deteriorate in quality even after receiving external force.SOLUTION: A polymer [A] having a moiety (a) represented by the formula (1) is blended in a liquid crystal alignment agent. In the formula (1), A1, A2 and A3 each represent a divalent aromatic ring group. At least one of divalent aromatic ring groups represented by A1-A3 has a structure with a group represented by "-CH2OR1" binding to an aromatic ring. B1 and B2 each represent a divalent group such as -O-, -S-, -NR2-, -CO-, -CO-O-, -O-CO-.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, a liquid crystal element, and a polymer. [Background technology]

[0002] Conventionally, various driving methods have been developed for liquid crystal elements, differing in electrode structure and physical properties of the liquid crystal molecules used, including various types of liquid crystal elements such as TN type, STN type, VA type, MVA type, in-plane switching type (IPS type), FFS type, and optically compensated bend type (OCB type). These liquid crystal elements have a liquid crystal alignment film for aligning the liquid crystal molecules. A liquid crystal alignment film is generally formed on a substrate by applying a liquid crystal alignment agent, which is made by dissolving or dispersing a polymer component in an organic solvent, to the substrate surface and preferably by heating.

[0003] In recent years, large-screen, high-definition LCD televisions have become mainstream, and compact display terminals such as smartphones and tablet PCs have become increasingly popular, further increasing the demand for higher quality LCD devices. In order to meet this demand for higher quality, various liquid crystal alignment agents have been proposed (see, for example, Patent Documents 1 and 2).

[0004] Patent Document 1 discloses that a crosslinkable additive is contained in a liquid crystal aligning agent together with a polyimide or a polyimide precursor as a low molecular weight compound that improves the hardness of the liquid crystal alignment film. Patent Document 2 discloses that a polymer obtained from a diamine having a specific structure is contained in a liquid crystal aligning agent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020 / 171128 [Patent Document 2] International Publication No. 2020 / 203110 Summary of the Invention [Problem to be solved by the invention]

[0006] As liquid crystal devices become higher definition and more versatile, quality requirements are becoming more stringent. For example, liquid crystal devices must not only have improved liquid crystal alignment and voltage holding ratio, but also must be able to withstand physical pressure, such as vibrations and tapping during transportation.

[0007] On the other hand, the demand for thinner LCD devices is accelerating, and the base materials (mainly glass substrates) of LCD devices are becoming thinner and thinner. As a result, the stress applied inside the LCD element is increasing more than ever before, and the occurrence of starting defects in pre-shipment tapping tests that take into account the recent increase in stress has become a problem. However, simply using cross-linking additives as in the past does not provide sufficient film strength, making it difficult to maintain quality.

[0008] In recent years, mobile display devices, such as smartphones and tablet PCs, have been designed with narrower bezels to maximize the touch panel's operating area while also miniaturizing the display. One known method for achieving this is to form a liquid crystal alignment film over the entire surface of the substrate, then apply a sealant to the liquid crystal alignment film and bond the substrates together. However, applying a sealant to the liquid crystal alignment film can easily apply pressure to the area of ​​the liquid crystal alignment film where the sealant is applied, which can easily lead to peeling between the substrates. To prevent quality loss due to physical pressure, such as vibrations and tapping during transportation, the liquid crystal alignment film must also have high adhesion to the substrate.

[0009] The present invention has been made in consideration of the above-mentioned problems, and has as its main object to provide a liquid crystal alignment agent that can form a liquid crystal alignment film that has good liquid crystal alignment properties and excellent adhesion to a substrate, and that can obtain a liquid crystal element that is suppressed from deteriorating in quality due to exposure to external force. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to solve the above problems and have found that the above problems can be solved by using a polymer having a specific structure, thereby completing the present invention. Specifically, the present invention provides the following means.

[0011] <1> A liquid crystal aligning agent comprising a polymer [A] having a partial structure (a) represented by the following formula (1): [ka] (In formula (1), A 1 , A 2 and A 3 are each independently a divalent aromatic ring group, and m is an integer of 0 to 2. However, when m is 0, A 1 and A 3 At least one of the divalent aromatic ring groups represented by "-CH2OR 1 " is bonded to an aromatic ring, and when m is 1 or 2, A 1 , A 2 and A 3 At least one of the divalent aromatic ring groups represented by "-CH2OR 1 " is bonded to an aromatic ring. 1 is a hydrogen atom or a monovalent organic group. 1 and B 2 are each independently -O-, -S-, or -NR 2 -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR 2 -CO-, -CO-NR 2 -, -NR 2 -CO-NR 3 - or an alkanediyl group having 1 to 14 carbon atoms, or an alkanediyl group having 2 to 14 carbon atoms in which any methylene group is -O-, -S-, or -NR 2 -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR 2 -CO-, -CO-NR 2 - and -NR 2 -CO-NR 3- is a divalent group in which R is substituted with at least one of 2 and R 3 are each independently a hydrogen atom or a monovalent organic group. When m is 2, multiple A 2 are the same or different, and multiple B 2 are the same or different. "*" represents a bond.)

[0012] <2> the above <1> A liquid crystal alignment film formed using the liquid crystal alignment agent of the above. <3> the above <2> A liquid crystal element comprising a liquid crystal alignment film. <4> A polyamic acid, a polyamic acid ester, and a polyimide having a partial structure represented by the above formula (1). [Effects of the Invention]

[0013] The liquid crystal aligning agent of the present invention can form a liquid crystal alignment film having good liquid crystal alignment properties and excellent adhesion to a substrate, and can also provide a liquid crystal device in which deterioration in quality is suppressed even when subjected to external force (for example, external force due to vibration or tapping). DETAILED DESCRIPTION OF THE INVENTION

[0014] Liquid crystal alignment agent Hereinafter, each component contained in the liquid crystal aligning agent of the present disclosure and other components that may be arbitrarily blended as necessary will be described.

[0015] In this specification, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Chain hydrocarbon group" refers to a straight-chain hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure in the main chain and is composed only of a chain structure. However, the chain hydrocarbon group may be saturated or unsaturated. "Alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. However, an alicyclic hydrocarbon group does not necessarily have to be composed only of an alicyclic hydrocarbon structure and may also have a chain structure as part of it. "Aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, an aromatic hydrocarbon group does not necessarily have to be composed only of an aromatic ring structure and may contain a chain structure or an alicyclic hydrocarbon structure as part of it.

[0016] "Main chain" refers to the longest "trunk" part of the atomic chain of a polymer. It is permissible for this "trunk" part to contain a ring structure. "Side chain" refers to the part branched from the "trunk" of a polymer. "Aromatic ring" includes aromatic hydrocarbon rings and aromatic heterocycles. "Organic group" refers to an atomic group formed by removing any hydrogen atom from a compound containing carbon (i.e., an organic compound). "Tetracarboxylic acid derivative" includes tetracarboxylic acid dianhydrides, tetracarboxylic acid diesters, and tetracarboxylic acid diester dihalides.

[0017] The liquid crystal aligning agent of the present disclosure contains a polymer [A] having a partial structure (a) represented by the following formula (1). [ka] (In formula (1), A 1 , A 2 and A 3 are each independently a divalent aromatic ring group, and m is an integer of 0 to 2. However, when m is 0, A 1 and A 3 At least one of the divalent aromatic ring groups represented by "-CH2OR 1 " is bonded to an aromatic ring, and when m is 1 or 2, A1 , A 2 and A 3 At least one of the divalent aromatic ring groups represented by "-CH2OR 1 " is bonded to an aromatic ring. 1 is a hydrogen atom or a monovalent organic group. 1 and B 2 are each independently -O-, -S-, or -NR 2 -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR 2 -CO-, -CO-NR 2 -, -NR 2 -CO-NR 3 - or an alkanediyl group having 1 to 14 carbon atoms, or an alkanediyl group having 2 to 14 carbon atoms in which any methylene group is -O-, -S-, or -NR 2 -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR 2 -CO-, -CO-NR 2 - and -NR 2 -CO-NR 3 - is a divalent group in which R is substituted with at least one of 2 and R 3 are each independently a hydrogen atom or a monovalent organic group. When m is 2, multiple A 2 are the same or different, and multiple B 2 are the same or different. "*" represents a bond.)

[0018] <Polymer [A]> Regarding the partial structure (a) The partial structure (a) has two or more aromatic rings, and at least one of the two or more aromatic rings has "-CH2OR 1" is bonded to the partial structure (a) (hereinafter also referred to as "specific aromatic ring structure"). In addition to the specific aromatic ring structure, the partial structure (a) also includes a spacer structure in which aromatic rings are linked together by a specific divalent group. By introducing the partial structure (a) including the specific aromatic ring structure and the spacer structure into the polymer component of the liquid crystal alignment film, it is possible to obtain a liquid crystal alignment film that is high in strength and has excellent liquid crystal alignment properties.

[0019] In formula (1), A 1 , A 2 and A 3 A divalent aromatic ring group represented by the formula (I) is a group in which any two hydrogen atoms have been removed from the ring portion of an aromatic ring. The aromatic ring contained in the divalent aromatic ring group may be an aromatic hydrocarbon ring or an aromatic heterocycle. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring. Examples of the aromatic heterocycle include a nitrogen-containing aromatic heterocycle, an oxygen-containing aromatic heterocycle, and a sulfur-containing aromatic heterocycle. Specific examples of the aromatic heterocycle include a pyridine ring, a pyrimidine ring, a pyridazine ring, and a pyrazine ring as a nitrogen-containing aromatic heterocycle; a furan ring as an oxygen-containing aromatic heterocycle; and a thiophene ring as a sulfur-containing aromatic heterocycle.

[0020] In order to increase the density of the liquid crystal alignment film and improve the strength and liquid crystal alignment of the liquid crystal alignment film, A 1 , A 2 and A 3 The aromatic ring contained in is preferably a benzene ring, a naphthalene ring or a pyridine ring, and more preferably a benzene ring.

[0021] The partial structure (a) is a divalent aromatic ring group (when m=0, A 1 and A 3 , if m=1 or 2, A 1 , A 2 and A 3 ) for at least one aromatic ring in the 1 In other words, when m is 0, the partial structure (a) has a structure in which a total of two aromatic ring groups (A1 and A 3 ) at least one of them is "-CH2OR 1 When m is 1, the partial structure (a) has a structure in which a group represented by the formula "A" is bonded to an aromatic ring. 1 , A 2 and A 3 ) at least one of them is "-CH2OR 1 When m is 2, the partial structure (a) contains a total of four aromatic ring groups (one A 1 , 2 As 2 and 1 A 3 ) at least one of them is "-CH2OR 1 In view of ease of synthesis and liquid crystal alignment properties, m is preferably 0 or 1.

[0022] R 1 Examples of the monovalent organic group represented by the formula (I) include a monovalent hydrocarbon group and a monovalent group that is eliminated by at least one of heat and light and replaced with a hydrogen atom (hereinafter also referred to as a "leaving group"). Specific examples of the monovalent hydrocarbon group include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 4 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 6 to 10 carbon atoms. Of these, an alkyl group and a phenyl group having 1 to 3 carbon atoms are preferred, and an alkyl group having 1 to 3 carbon atoms is more preferred.

[0023] The monovalent leaving group is preferably a group that is released by heat (preferably by heating during film formation) (hereinafter also referred to as "thermally leaving group"). Specific examples of the thermally leaving group include carbamate-based leaving groups such as tert-butoxycarbonyl (Boc), benzyloxycarbonyl, 1,1-dimethyl-2-haloethyloxycarbonyl, allyloxycarbonyl, and 2-(trimethylsilyl)ethoxycarbonyl; ether-based leaving groups such as alkyl groups having 1 to 7 carbon atoms, benzyl, and p-methoxybenzyl; acetal-based leaving groups such as methoxymethyl, ethoxyethyl, and 2-tetrahydropyranyl; acyl-based leaving groups such as acetyl and benzoyl; allyl-based leaving groups such as allyl and methallyl; and silyl ether-based leaving groups such as trimethylsilyl, triethylsilyl, and tert-butyldimethylsilyl. From the viewpoint of achieving both ease of thermal elimination and storage stability, among these, a carbamate-based leaving group, an ether-based protecting group, an acetal-based protecting group, or an acetyl group is preferred, and a tert-butoxycarbonyl group, an alkyl group having 1 to 3 carbon atoms, a 2-tetrahydropyranyl group, a methoxymethyl group, a 1-ethoxyethyl group, or an acetyl group is more preferred.

[0024] R 1 is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a monovalent thermally detachable group, and more preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a tert-butoxycarbonyl group, a 2-tetrahydropyranyl group, a methoxymethyl group, a 1-ethoxyethyl group, or an acetyl group.

[0025] Each substructure (a) has "-CH2OR 1 The number of "-CH2OR" bonded to one aromatic ring in the specific aromatic ring structure is preferably 1 to 4, more preferably 1 or 2, from the viewpoint of achieving a good balance between improving the film strength and achieving good liquid crystal alignment. 1 The number of " is preferably 1 or 2.

[0026] In addition, A 1 , A 2 and A 3The aromatic ring contained in is "-CH2OR 1 " may have a substituent (hereinafter also referred to as "other substituent") other than the group represented by "-CH2OR". Examples of other substituents include an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a halogen atom, a hydrogen atom, a cyano group, etc. 1 From the viewpoint of promoting the crosslinking reaction of the group represented by A 1 , A 2 and A 3 The number of other substituents that the aromatic rings contained in the formula (I) have is preferably 0 to 2, more preferably 0 or 1, and even more preferably 0 (i.e., no other substituents) per aromatic ring.

[0027] B 1 and B 2 -O-, -S-, -NR 2 -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR 2 -CO-, -CO-NR 2 -, -NR 2 -CO-NR 3 - or an alkanediyl group having 1 to 14 carbon atoms, or an alkanediyl group having 2 to 14 carbon atoms in which any methylene group is -O-, -S-, or -NR 2 -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR 2 -CO-, -CO-NR 2 - and -NR 2 -CO-NR 3 - (hereinafter also referred to as "specific heteroatom-containing group") 1 "). B 1 and B 2 may be the same as or different from each other.

[0028] B 1 and B 2 The alkanediyl group having 1 to 14 carbon atoms represented by the formula (I) may be linear or branched.1 and B 2 In view of liquid crystal alignment properties, a linear alkanediyl group having 1 to 10 carbon atoms is preferred, a linear alkanediyl group having 2 to 10 carbon atoms is more preferred, and a linear alkanediyl group having 4 to 10 carbon atoms is even more preferred.

[0029] R 2 and R 3 Examples of the monovalent organic group represented by the formula (I) include a monovalent hydrocarbon group and a leaving group. Specific examples of the monovalent hydrocarbon group include R 1 The explanations of the examples and preferred examples of the monovalent hydrocarbon group represented by the formula (I) can be applied. The monovalent leaving group is preferably a thermally leaving group. Specifically, a tert-butoxycarbonyl group or a 9-fluorenylmethyloxycarbonyl group is preferred, and a tert-butoxycarbonyl group (Boc group) is particularly preferred. R 2 and R 3 is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a monovalent thermally detachable group, more preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a tert-butoxycarbonyl group, and even more preferably a hydrogen atom or a tert-butoxycarbonyl group.

[0030] B 1 and B 2 A divalent group E represented by 1 In terms of improving the liquid crystal alignment property, it is preferable that the specific heteroatom-containing group is a group in which any methylene group in a linear alkanediyl group is replaced by the specific heteroatom-containing group described above. In this case, the specific heteroatom-containing group is preferably an electron-donating group (-O-, -S-, -NR 2 -, *-O-CO-, *-O-CS-, *-NR 2 -CO-, -NR 2 -CO-NR 3 - (where "*" represents a bond to the aromatic ring) is preferred.

[0031] Divalent group E 1 is the group E 1A divalent aromatic ring group (A 1 , A 2 or A 3 ) is "-CH2OR 1 " has a structure in which a group represented by "-CH2OR 1 " is bonded to an aromatic ring, -O-, -S-, -NR 2 -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR 2 -CO-, -CO-NR 2 -or-NR 2 -CO-NR 3 It is preferable that these groups are bonded directly to the specific aromatic ring structure, in that a liquid crystal alignment film having good liquid crystal alignment properties and good adhesion to the substrate can be obtained, and in that the effect of suppressing deterioration in display quality due to vibration or tapping can be enhanced.

[0032] Divalent group E 1 Specifically, is preferably a group represented by the following formula (G-1). [ka] (In formula (G-1), X 1 and X 2 are each independently -O-, -S-, or -NR 2 -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR 2 -CO-, -CO-NR 2 -or-NR 2 -CO-NR 3 -R 4 is an alkanediyl group having 1 to 6 carbon atoms. n is 1 or 2. R 2 and R 3 is the same as formula (1). "*" represents a bond.

[0033] In formula (G-1), X 1 and X 2 From the viewpoint of obtaining a liquid crystal alignment film that has a high effect of improving film strength while maintaining liquid crystal alignment, -O-, -S-, and -NR 2-, *-O-CO-, *-O-CS-, *-NR 2 -CO-, -NR 2 -CO-NR 3 - (where "*" represents a bond to the aromatic ring) is preferred, and -O-, -S- or -NR 2 - is more preferred.

[0034] B 1 and B 2 Among the above, an alkanediyl group having 1 to 14 carbon atoms or a divalent group E is preferred in that it can form an organic film that exhibits good liquid crystal alignment properties. 1 In addition, B is preferable in that it can enhance the effect of improving the film strength while maintaining good liquid crystal alignment. 1 and B 2 is a divalent group E 1 It is more preferable that it is a group represented by formula (G-1), and it is even more preferable that it is a group represented by formula (G-1).

[0035] Specific examples of the partial structure (a) include structures represented by the following formulas (1-1) to (1-29). [ka] [ka]

[0036] [ka]

[0037] [ka] (In the formula, "*" represents a bond.)

[0038] The polymer [A] may have the partial structure (a) in the main chain or in the side chain. From the viewpoint of enhancing the effect of improving the liquid crystal alignment property and film strength of the liquid crystal alignment film by introducing the partial structure (a), it is preferable that the polymer [A] has the partial structure (a) in the main chain. Note that when the polymer [A] "has the partial structure (a) in the main chain," it includes not only the case where the polymer [A] has the partial structure (a) only in the main chain, but also the case where the polymer [A] has the partial structure (a) in the main chain and in the side chain.

[0039] In the polymer [A], the content of the partial structure (a) is preferably 2 mol% or more relative to the total amount of monomer units contained in the polymer [A], from the viewpoint of obtaining a liquid crystal device that exhibits good liquid crystal alignment properties and high adhesion. From the above viewpoints, the content of the partial structure (a) is more preferably 5 mol% or more, and even more preferably 7 mol% or more, relative to the total amount of monomer units contained in the polymer [A]. Furthermore, the content of the partial structure (a) can be appropriately set depending on the main chain of the polymer [A], but is, for example, 60 mol% or less, preferably 50 mol% or less, relative to the total amount of monomer units contained in the polymer [A]. Note that the polymer [A] may contain only one type of partial structure (a), or two or more types.

[0040] The main skeleton of the polymer [A] is not particularly limited. Among them, the polymer [A] is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, in terms of being able to form a liquid crystal alignment film that has high affinity with liquid crystals and mechanical strength and is highly reliable, and being able to easily introduce the partial structure (a) into the polymer main chain.

[0041] The method for producing the polymer [A] is not particularly limited as long as the partial structure (a) can be introduced into the polymer. In terms of ease of introduction of the partial structure (a) into the polymer, the polymer [A] 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 having the partial structure (a) (hereinafter also referred to as a "specific diamine") in terms of the ability to form a liquid crystal alignment film having high affinity with liquid crystals and mechanical strength, and the high degree of freedom in monomer design.

[0042] (specific diamine) The specific diamine may be a compound having the partial structure (a) and two primary amino groups, and the structure of the other parts is not particularly limited. Specifically, the specific diamine is preferably a compound represented by the following formula (2): [ka] (In formula (2), D 1 and D 2 A is each independently a single bond or a divalent organic group. 1 , A 2 , A 3 , B 1 , B 2 and m are defined as in formula (1).

[0043] In equation (2), D 1 and D 2 Examples of the divalent organic group represented by the formula (I) include a chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a nitrogen-containing heterocyclic group. 1 and D 2 The divalent organic group represented by the formula (I) is preferably an aromatic hydrocarbon group or a nitrogen-containing heterocyclic group, and more preferably a substituted or unsubstituted phenylene group. In the substituted phenylene group, the substituent may be an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a halogen atom, or the like. D 1 and D 2is preferably a single bond, a substituted or unsubstituted phenylene group, or a substituted or unsubstituted pyridylene group, and more preferably a substituted or unsubstituted phenylene group.

[0044] In addition, A 1 , A 2 , A 3 , B 1 , B 2 For specific and preferred examples of and m, the explanation for formula (1) applies.

[0045] When a primary amino group (more specifically, a primary amino group involved in polymerization) is bonded to an aromatic ring contained in a specific aromatic ring structure, "-CH2OR 1 The group represented by the formula (I) is preferably located at the ortho- or meta-position relative to the primary amino group, and more preferably at the meta-position in that it can further enhance the effect of improving film strength.

[0046] Specific examples of the specific diamine include compounds represented by the following formulas (3-1) to (3-29). [ka] [ka]

[0047] [ka] [ka]

[0048] [ka]

[0049] <Polyamic acid> When the polymer [A] is a polyamic acid, the polyamic acid (hereinafter also referred to as "polyamic acid [A]") can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine compound containing a specific diamine.

[0050] (Tetracarboxylic acid dianhydride) When synthesizing the polyamic acid [A], one tetracarboxylic dianhydride may be used alone, or two or more tetracarboxylic dianhydrides may be used in combination. Examples of the tetracarboxylic dianhydride used in synthesizing the polyamic acid [A] include aliphatic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides. Aliphatic tetracarboxylic dianhydrides include chain tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides.

[0051] Specific examples of the tetracarboxylic acid dianhydride include chain tetracarboxylic acid dianhydrides such as 1,2,3,4-butanetetracarboxylic acid dianhydride and ethylenediaminetetraacetic acid dianhydride. Examples of the alicyclic tetracarboxylic acid dianhydride include 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione ... (1,2-dihydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, and 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride.

[0052] Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol bisanhydrotrimate, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 4,4'-carbonyldiphthalic anhydride, and 3,3',4,4'-biphenyltetracarboxylic dianhydride. Furthermore, in synthesizing the polyamic acid [A], the tetracarboxylic dianhydride described in JP-A-2010-97188 can also be used.

[0053] The tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid [A] preferably contains an aliphatic tetracarboxylic acid dianhydride, and more preferably contains an alicyclic tetracarboxylic acid dianhydride, in that it has high solubility and can produce a liquid crystal alignment film that exhibits good liquid crystal alignment properties and electrical properties. The amount of the alicyclic tetracarboxylic acid dianhydride used is preferably 20 mol % or more, more preferably 40 mol % or more, and even more preferably 50 mol % or more, based on the total amount of tetracarboxylic acid dianhydrides used in the synthesis of the polyamic acid [A].

[0054] (diamine compounds) When synthesizing the polyamic acid [A], one diamine compound may be used alone, or two or more diamine compounds may be used in combination. The diamine compound used in the synthesis of the polyamic acid [A] may consist solely of the specific diamine, but may also contain a diamine compound not having the partial structure (a) (hereinafter also referred to as "other diamines"). Examples of other diamines include aliphatic diamines, aromatic diamines, and diaminoorganosiloxanes. Aliphatic diamines include chain diamines and alicyclic diamines.

[0055] Specific examples of other diamines include chain diamines such as metaxylylenediamine and hexamethylenediamine, alicyclic diamines such as 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine), and diaminoorganosiloxanes such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane.

[0056] Aromatic diamines include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4-aminophenyl-4-aminobenzoate, 4,4'-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, 6,6'-(pentamethylenedioxy)bis(3-aminopyridine), N,N'-di(5-amino-2-pyridyl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine, bis[2-(4-aminophenyl)ethyl]hexanedioic acid, 4,4 '-diaminodiphenyl ether, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenethyl urea, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-(phenylenediisopropylidene)bisaniline, 2,6-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 3,6-diaminoacridine, diphenylamine structure-containing monomers, the following formula (F-1): [ka] (In formula (F-1), R 21 and R 22 are each independently an alkanediyl group. 23is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a leaving group. r1 is an integer of 1 to 3. When r1 is 2 or 3, multiple R 22 are the same or different, and multiple R 23 are the same or different.) Main chain diamines such as compounds represented by the following formula: Hexadecanoxy-2,4-diaminobenzene, Octadecanoxy-2,4-diaminobenzene, Octadecanoxy-2,5-diaminobenzene, Cholestanyloxy-3,5-diaminobenzene, Cholesteryloxy-3,5-diaminobenzene, Cholestanyloxy-2,4-diaminobenzene, Cholesteryloxy-2,4-diaminobenzene, Cholestanyloxy-3,5-diaminobenzoate, Cholesteryl 3,5-diaminobenzoate , lanostannyl 3,5-diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 3,5-diaminobenzoic acid = 5ξ-cholestan-3-yl, the following formula (E-1): [ka] (In formula (E-1), X I and X II are each independently a single bond, -O-, *-COO- or *-OCO- (where "*" represents X I It shows the bond with R. I is an alkanediyl group having 1 to 3 carbon atoms. II R is a single bond or an alkanediyl group having 1 to 3 carbon atoms. III is an alkyl group, alkoxy group, fluoroalkyl group, or fluoroalkoxy group having 1 to 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, provided that 1≦a+b+c≦3. and side chain diamines such as compounds represented by the following formula:

[0057] Examples of the compound represented by formula (F-1) include compounds represented by the following formulas (F-1-1) to (F-1-3). Examples of the compound represented by formula (E-1) include compounds represented by the following formulas (E-1-1) to (E-1-4). As the other diamines, one type can be used alone, or two or more types can be used in combination. [ka]

[0058] In producing the polyamic acid [A], the amount of the specific diamine used is preferably 5 mol % or more, more preferably 10 mol % or more, and even more preferably 20 mol % or more, based on the total amount of the diamine compounds used in the synthesis of the polyamic acid [A].

[0059] (Synthesis of polyamic acid) The polyamic acid [A] can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound, optionally together with a molecular weight modifier.

[0060] In the synthesis reaction of the polyamic acid [A], the ratio of the tetracarboxylic dianhydride to the diamine compound is preferably such that 0.2 to 2 equivalents of the acid anhydride group of the tetracarboxylic dianhydride are used per equivalent of the amino group of the diamine compound. Examples of molecular weight modifiers include 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 ratio of the molecular weight modifier used is preferably 20 parts by mass or less per 100 parts by mass of the total of the tetracarboxylic dianhydride and diamine compound used.

[0061] The synthesis reaction of the polyamic acid [A] is preferably carried out in an organic solvent. The reaction temperature is preferably −20° C. to 150° C., and the reaction time is preferably 0.1 to 24 hours. Examples of organic solvents used in the reaction include aprotic polar solvents, phenolic solvents, alcoholic solvents, ketone solvents, ester solvents, ether solvents, halogenated hydrocarbons, and hydrocarbons. Among these, it is preferable to use one or more solvents selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenols as the reaction solvent, or to use a mixture of one or more solvents selected from the group consisting of butyl cellosolve, diethylene glycol diethyl ether, and the like. The amount of the organic solvent used is preferably an amount such that the total amount of the tetracarboxylic dianhydride and the diamine compound is 0.1 to 50% by mass based on the total amount of the reaction solution.

[0062] In this way, a polymer solution containing the polyamic acid [A] dissolved therein is obtained. This polymer solution may be used as it is for preparing a liquid crystal aligning agent, or the polyamic acid [A] contained in the polymer solution may be isolated and then used for preparing a liquid crystal aligning agent.

[0063] <Polyamic acid ester> When the polymer [A] is a polyamic acid ester, the polyamic acid ester (hereinafter also referred to as "polyamic acid ester [A]") can be obtained, for example, by a method such as [I] reacting a polyamic acid [A] with an esterifying agent, [II] reacting a tetracarboxylic acid diester with a diamine compound containing a specific diamine, or [III] reacting a tetracarboxylic acid diester dihalide with a diamine compound containing a specific diamine. The polyamic acid ester [A] 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 in which the polyamic acid ester [A] is dissolved may be used directly for preparing a liquid crystal aligning agent, or the polyamic acid ester [A] contained in the reaction solution may be isolated and then used for preparing a liquid crystal aligning agent.

[0064] <Polyimide> When the polymer [A] is a polyimide, the polyimide (hereinafter also referred to as "polyimide [A]") can be obtained, for example, by imidizing the polyamic acid [A] synthesized as described above through dehydration and cyclization. The polyimide [A] may be a fully imidized product in which all of the amic acid structures contained in its precursor polyamic acid [A] have been dehydrated and cyclized, or a partially imidized product in which only a portion of the amic acid structures have been dehydrated and cyclized, resulting in both amic acid structures and imide ring structures. The polyimide [A] preferably has an imidization rate of 20 to 99%, more preferably 30 to 90%. The imidization rate is the ratio, expressed as a percentage, of the number of imide ring structures to the total number of amic acid structures and imide ring structures in the polyimide. Here, some of the imide rings may be isoimide rings.

[0065] The dehydration ring closure of the polyamic acid [A] is preferably carried out by dissolving the polyamic acid [A] in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating as needed. In this method, the dehydrating agent may be, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride. The amount of the dehydrating agent used is preferably 0.01 to 20 moles per mole of the amic acid structure of the polyamic acid [A]. The dehydration ring closure catalyst may be, for example, a tertiary amine such as pyridine, collidine, lutidine, or triethylamine. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. Examples of organic solvents used in the dehydration ring closure reaction include the organic solvents exemplified for use in the synthesis of the polyamic acid [A]. The reaction temperature for the dehydration ring closure reaction is preferably 0 to 180°C. The reaction time is preferably 1.0 to 120 hours. The reaction solution containing the polyimide [A] may be used for preparing a liquid crystal aligning agent as it is, or the polyimide [A] may be isolated and then used for preparing a liquid crystal aligning agent.

[0066] When the polymer [A] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, the solution viscosity of the polymer [A] is preferably 10 to 800 mPa·s, and more preferably 15 to 500 mPa·s, when the polymer is prepared as a 10% by mass solution. The solution viscosity (mPa·s) is a value measured at 25°C using an E-type rotational viscometer for a 10% by mass polymer solution prepared using a good solvent for the polymer [A] (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0067] The weight average molecular weight (Mw) of the polymer [A] measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. The molecular weight distribution (Mw / Mn), which is the ratio of Mw to the number average molecular weight (Mn) measured by GPC in terms of polystyrene, is preferably 7 or less, more preferably 5 or less. When preparing the liquid crystal aligning agent, one type of polymer [A] may be used alone, or two or more types may be used in combination.

[0068] The content of the polymer [A] in the liquid crystal aligning agent is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, relative to 100 parts by mass of the solid content (total of components other than the solvent of the liquid crystal aligning agent) contained in the liquid crystal aligning agent. When the content of the polymer [A] is within the above range, it is preferable in that the film strength, adhesion to the substrate, and liquid crystal alignment can be sufficiently improved.

[0069] <Other ingredients> The liquid crystal aligning agent may contain, in addition to the polymer [A], components different from the polymer [A] (hereinafter also referred to as "other components"), if necessary.

[0070] (Polymer [Q]) The liquid crystal aligning agent of the present disclosure may further contain, as a polymer component, a polymer not having the partial structure (a) (hereinafter also referred to as "polymer [Q]").

[0071] The main skeleton of the polymer [Q] is not particularly limited. Examples of the polymer [Q] include polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamideimide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, and addition polymer. From the viewpoint of obtaining a highly reliable liquid crystal device, the polymer [Q] is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer. Examples of the addition polymer include (meth)acrylic polymers, styrene polymers, maleimide polymers, and styrene-maleimide copolymers.

[0072] When the liquid crystal aligning agent of the present disclosure contains polymer [A] and polymer [Q] together, the content of polymer [Q] is preferably 1% by mass or more, more preferably 2% by mass or more, based on the total amount of polymer [A] and polymer [Q]. The content of polymer [Q] is preferably 95% by mass or less, more preferably 90% by mass or less, based on the total amount of polymer [A] and polymer [Q]. Polymer [Q] may be used singly or in combination of two or more.

[0073] (solvent) The liquid crystal aligning agent of the present disclosure is prepared as a liquid composition in which a polymer component and other components used as needed are dispersed or dissolved preferably in a suitable solvent.

[0074] As the solvent, an organic solvent is preferably used, specific examples of which include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, phenol, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,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 acetoacetate, ethyl propionate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, and ethylene glycol-i-propyl ether. Examples of suitable solvents include ethylene glycol 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, diisopentyl ether, ethylene carbonate, propylene carbonate, propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentanone, cyclohexanone, etc. The solvent may be used alone or in combination of two or more.

[0075] In addition to the above, other components contained in the liquid crystal aligning agent include, for example, a crosslinking agent, an antioxidant, a metal chelate compound, a curing accelerator, a surfactant, a filler, a dispersant, a photosensitizer, etc. The blending ratio of the other components can be appropriately selected depending on each compound within a range that does not impair the effects of the present disclosure.

[0076] The solid content concentration in the liquid crystal aligning agent (the proportion of the total mass of the components other than the solvent in the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected taking into consideration viscosity, volatility, etc., but is preferably in the range of 1 to 10 mass %. A solid content concentration of 1 mass % or more is preferable in that it ensures a sufficient coating film thickness and makes it possible to obtain a liquid crystal alignment film that exhibits better liquid crystal alignment properties. On the other hand, a solid content concentration of 10 mass % or less makes it possible to make the coating film have an appropriate thickness, making it easier to obtain a liquid crystal alignment film that exhibits good liquid crystal alignment properties, and also tends to make the viscosity of the liquid crystal aligning agent appropriate, resulting in good coatability.

[0077] Here, the liquid crystal alignment agent containing the polymer [A] improves the liquid crystal alignment property and adhesion to the substrate, and also provides a liquid crystal element with high film strength and suppressed deterioration in quality due to external force. The reason for this is unclear, but one possible reason is that the polymer [A] has a specific aromatic ring structure, and therefore, when heated during film formation, for example, the polymer [A] may convert to "-CH2OR 1 " is likely to facilitate high-density crosslinking between polymers, thereby enabling the production of a liquid crystal alignment film in which the occurrence of film rupture is suppressed. In polymer [A], it is assumed that crosslinking proceeds through a condensation reaction with the electron-rich aromatic ring of partial structure (a), an addition reaction with carboxylic acid, an exchange reaction with ester, etc. Furthermore, since the aromatic rings of polymer [A] are linked by a spacer structure, it is likely that the polymer exhibits good liquid crystal alignment properties while having high film strength. However, these speculations do not limit the present disclosure.

[0078] <Liquid crystal alignment film and liquid crystal element> The liquid crystal alignment film of the present disclosure is manufactured using the liquid crystal alignment agent prepared as described above. Furthermore, the liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The liquid crystal driving method in the liquid crystal element is not particularly limited, and can be applied to various modes, such as TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS (In-Plane Switching) type, FFS (Fringe Field Switching) type, OCB (Optically Compensated Bend) type, and PSA (Polymer Sustained Alignment) type. The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, different substrates are used depending on the desired operation mode. Steps 2 and 3 are common to all operation modes.

[0079] <Step 1: Formation of coating film> First, a liquid crystal alignment agent is applied to a substrate, and the coated surface is preferably heated to form a coating film on the substrate. Examples of substrates that can be used include transparent substrates made of glass, such as float glass or soda glass; or plastics, such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefin). When manufacturing TN, STN, or VA liquid crystal devices, two substrates with patterned transparent conductive films are used. On the other hand, when manufacturing IPS or FFS liquid crystal devices, one substrate with comb-shaped patterned electrodes and a counter substrate without electrodes are used. Examples of transparent conductive films that can be used include NESA films (registered trademark of PPG, USA) made of tin oxide (SnO2), and ITO films made of indium oxide-tin oxide (In2O3-SnO2).

[0080] The method for applying the liquid crystal aligning agent to the substrate is not particularly limited. The liquid crystal aligning agent can be applied to the substrate by, for example, a spin coating method, a printing method (for example, an offset printing method, a flexographic printing method, etc.), an inkjet method, a slit coating method, a bar coater method, an extrusion die method, a direct gravure coater method, a chamber doctor coater method, an offset gravure coater method, an impregnation coater method, an MB coater method, etc.

[0081] After the liquid crystal aligning agent is applied, preliminary heating (pre-baking) is preferably carried out for the purpose of preventing dripping of the applied liquid crystal aligning agent. The pre-baking temperature is preferably 30 to 200°C, and the pre-baking time is preferably 0.25 to 10 minutes. Thereafter, the solvent is completely removed, and if necessary, a baking (post-baking) step is carried out for the purpose of thermally imidizing the amic acid structure present in the polymer. The baking temperature (post-baking temperature) at this time is preferably 80 to 280°C, more preferably 80 to 250°C. The post-baking time is preferably 5 to 200 minutes. The thickness (film thickness) of the formed film is preferably 0.001 to 1 μm.

[0082] <Step 2: Alignment Treatment> When manufacturing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal device, the coating film formed in step 1 above is subjected to a treatment (alignment treatment) to impart liquid crystal alignment ability. This imparts the ability to align liquid crystal molecules to the coating film, turning it into a liquid crystal alignment film. As the alignment treatment, a rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton, nylon, or the like, or a photo-alignment treatment in which the coating film is irradiated with light to impart liquid crystal alignment ability is preferably used. When manufacturing a vertical alignment type liquid crystal device, the coating film formed in step 1 above may be used as is as a liquid crystal alignment film, or the coating film may be subjected to an alignment treatment to further enhance the liquid crystal alignment ability.

[0083] Light irradiation for photoalignment can be performed by irradiating the coating film after the post-bake step, irradiating the coating film after the pre-bake step but before the post-bake step, or irradiating the coating film while it is being heated in at least one of the pre-bake step and the post-bake step. The radiation to be irradiated to the coating film can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm. Preferably, ultraviolet light containing light with a wavelength of 200 to 400 nm is used. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When non-polarized radiation is used, the irradiation direction is an oblique direction.

[0084] Examples of light sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, excimer lasers, etc. The radiation dose is preferably 200 to 30,000 J / m 2 and more preferably 500 to 10,000 J / m 2 After the light irradiation for imparting alignment ability, the substrate surface may be washed with, for example, water, an organic solvent (e.g., methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.) or a mixture thereof, or the substrate may be heated.

[0085] <Step 3: Construction of liquid crystal cell> In this process, two substrates each having a liquid crystal alignment film formed thereon are prepared, and a liquid crystal is placed between the two substrates facing each other to produce a liquid crystal cell. Examples of methods for producing a liquid crystal cell include placing two substrates facing each other with a gap between them so that the liquid crystal alignment films face each other, bonding the peripheries of the two substrates together with a sealant, injecting liquid crystal into the cell gap surrounded by the substrate surfaces and the sealant, and sealing the injection hole, and using the ODF method. Examples of sealants that can be used include epoxy resins containing a curing agent and aluminum oxide spheres as spacers. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred.

[0086] In the PSA mode, a polymerizable compound (e.g., a polyfunctional (meth)acrylate compound) is filled into 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 producing a PSA mode liquid crystal element, the proportion of the polymerizable compound used is 0.01 to 3 parts by mass, preferably 0.1 to 1 part by mass, per 100 parts by mass of the total liquid crystal.

[0087] When manufacturing a liquid crystal display device, a polarizing plate is subsequently attached to the outer surface of the liquid crystal cell. Examples of polarizing plates include a polarizing film called an "H film" made by stretching and aligning polyvinyl alcohol and absorbing iodine, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

[0088] The liquid crystal element of the present disclosure can be effectively applied to various applications, specifically, for example, various display devices such as clocks, portable game machines, word processors, personal computers (notebook and desktop), car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays, as well as light control devices and retardation films.

[0089] According to the present disclosure described above in detail, the following means are provided. [Means 1] A liquid crystal aligning agent containing a polymer [A] having a partial structure (a) represented by the above formula (1). [Means 2] B in the above formula (1) 1 and B 2 Among them, "-CH2OR 1 " is bonded to an aromatic ring, and the group adjacent to the divalent aromatic ring group is "-CH2OR 1 " is bonded to an aromatic ring, -O-, -S-, -NR 2 -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR 2 -CO-, -CO-NR 2 -or-NR 2 -CO-NR 3 The liquid crystal aligning agent according to claim 1, wherein the liquid crystal aligning agent is bonded to the liquid crystal aligning agent by bonding with the liquid crystal aligning agent. [Means 3] The liquid crystal aligning agent according to means 1 or 2, wherein the polymer [A] contains a structural unit derived from a diamine having the partial structure (a). [Means 4] The liquid crystal aligning agent according to Means 3, wherein the diamine is a compound represented by the above formula (2). [Means 5] The liquid crystal aligning agent according to any one of Means 1 to Means 4, wherein the polymer [A] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. [Means 6] The liquid crystal aligning agent according to any one of means 1 to means 5, further comprising a polymer [Q] that does not have the partial structure (a). [Means 7] The liquid crystal aligning agent according to Means 6, wherein the polymer [Q] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane and addition polymer. [Means 8] A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of means 1 to means 7. [Means 9] A liquid crystal element comprising the liquid crystal alignment film of means 8. [Means 10] A polymer which is a polyamic acid, a polyamic acid ester or a polyimide and has a partial structure represented by the above formula (1). [Example]

[0090] Hereinafter, the present invention will be described in more detail based on examples, but the present invention should not be construed as being limited by the following examples.

[0091] In the following examples, the imidization rate of polyimide in the polymer solution was measured by the following method. [Imidization rate of polyimide] The polyimide solution was poured into pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. After that, it was dissolved in deuterated dimethyl sulfoxide and measured at room temperature using tetramethylsilane as a standard substance. 1 H-NMR measurement was carried out. 1 The imidization rate [%] was calculated from the H-NMR spectrum using the following formula (1). Imidization rate [%] = (1 - (A 1 / (A 2 ×α)))×100 …(1) (In formula (1), A 1 is the peak area due to the proton of the NH group that appears at a chemical shift of around 10 ppm, and A 2 is the peak area due to other protons, and α is the ratio of the number of other protons to one proton of the NH group in the polymer precursor (polyamic acid).

[0092] The required amounts of raw material compounds and polymers used in the following examples were ensured by repeating synthesis on a synthesis scale as necessary, as shown in the following synthesis examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified.

[0093] The abbreviations for the compounds are as follows: In the following, the compound represented by formula (X) may be simply referred to as "compound (X)".

[0094] (Tetracarboxylic acid dianhydride) [ka]

[0095] (diamine compounds) [ka] [ka]

[0096] [ka] [ka] [ka]

[0097] (Other compounds) [ka]

[0098] <Polymer synthesis> 1. Synthesis of polyamic acid [Synthesis Example 1] 100 parts by mole of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (compound (b-1)) as a tetracarboxylic dianhydride and 100 parts by mole of compound (DA-1) as a diamine compound were dissolved in N-methyl-2-pyrrolidone (NMP), and the mixture was allowed to react at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamic acid (referred to as polymer (PAA-1)).

[0099] [Synthesis Examples 2 to 27] Polyamic acids (polymers (PAA-2) to (PAA-19) and polymers (paa-1) to (paa-8)) were obtained by the same procedure as in Synthesis Example 1, except that the types and amounts of the tetracarboxylic dianhydrides and diamine compounds used were changed as shown in Table 1. In Table 1, the numerical values ​​for the tetracarboxylic dianhydrides (acid dianhydrides 1 to 3) represent the ratio (molar ratio) of each compound to 100 parts by mole of the total amount of the tetracarboxylic dianhydrides used in the synthesis of the polyamic acid. The numerical values ​​for the diamine compounds (diamines 1 to 4) represent the ratio (molar ratio) of each compound to 100 parts by mole of the total amount of the diamine compounds used in the synthesis of the polyamic acid.

[0100] [Table 1]

[0101] 2. Polyimide Synthesis [Synthesis Example 28] 100 moles of compound (b-2) as a tetracarboxylic dianhydride, 20 moles of compound (DA-2) as a diamine compound, 50 moles of compound (a-11), and 30 moles of compound (a-4) were dissolved in NMP and reacted at room temperature for 6 hours to obtain a solution containing 15% by weight of polyamic acid. Next, NMP was added to the resulting polyamic acid solution to obtain a solution with a polyamic acid concentration of 10% by weight, and pyridine and acetic anhydride were added to perform a dehydration ring-closing reaction at 60°C for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by weight of polyimide (referred to as polymer (PI-1)) with an imidization rate of approximately 80%.

[0102] [Synthesis Examples 29-39] Polyimides (polymers (PI-2) to (PI-9) and (PI-1) to (PI-3)) were obtained by the same procedure as in Synthesis Example 28, except that the types and amounts of the tetracarboxylic dianhydrides and diamine compounds used were changed as shown in Table 2. In Table 2, the numerical values ​​for the diamine compounds (diamines 1 to 4) represent the ratio (molar ratio) of each compound to 100 parts by mole of the total amount of the diamine compounds used in the synthesis of the polyimide.

[0103] [Table 2]

[0104] 3. Synthesis of polyorganosiloxane [Synthesis Example 40] A 1000 ml three-neck flask was charged with 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (compound (s-1)), 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine, and the mixture was mixed at room temperature. Next, 100 g of deionized water was added dropwise from the dropping funnel over 30 minutes, and the mixture was then refluxed and mixed at 80°C for 6 hours. After the reaction was complete, the organic layer was removed and washed with a 0.2% by weight aqueous solution of ammonium nitrate until the water was neutral, after which the solvent and water were distilled off under reduced pressure. An appropriate amount of methyl isobutyl ketone was added to obtain a 50% by weight solution of polymer (ESSQ-1), a polyorganosiloxane having epoxy groups. In a 500 ml three-neck flask, 3.10 g of compound (c-1) (20 mol% relative to the amount of epoxy groups in the polymer (ESSQ-1)), 3.24 g of compound (c-2) (10 mol% relative to the amount of epoxy groups in the polymer (ESSQ-1)), 1.00 g of tetrabutylammonium bromide, 20.0 g of a solution containing the polymer (ESSQ-1), and 290.0 g of methyl isobutyl ketone were added and stirred at 90 ° C. for 18 hours. After cooling to room temperature, the separation and washing operation with distilled water was repeated 10 times. The organic layer was then recovered, concentrated using a rotary evaporator, and diluted with NMP twice. The solids concentration was then adjusted to 10% by mass using NMP to obtain an NMP solution of polyorganosiloxane (referred to as polymer (PSQ-1)).

[0105] 4. Synthesis of styrene-maleimide copolymer [Synthesis Example 41] Under nitrogen, 5.00 g of compound (M-1), 1.05 g of compound (M-2), 4.80 g of compound (M-3), and 2.26 g of compound (M-4) were added to a 100 mL two-neck flask as polymerization monomers, 0.39 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, 0.39 g of 2,4-diphenyl-4-methyl-1-pentene as a chain transfer agent, and 52.5 mL of N-methyl-2-pyrrolidone (NMP) as a solvent, and polymerization was carried out for 6 hours at 70 °C. After reprecipitation in methanol, the precipitate was filtered and dried under vacuum at room temperature for 8 hours to obtain the target polymer (referred to as polymer (MI-1)).

[0106] <Preparation and Evaluation of Liquid Crystal Alignment Agent> [Example 1: Optical FFS type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent A solution containing 90 parts by mass of the polymer (PAA-1) obtained in Synthesis Example 1 and a solution containing 10 parts by mass of the polymer (pi-1) obtained in Synthesis Example 35 were mixed and diluted with NMP and BC to obtain a solution with a solvent composition of NMP / BC=80 / 20 (mass ratio) and a solids concentration of 3.5% by mass. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-1).

[0107] 2. Fabrication of FFS-type LCD elements using the photoalignment method A glass substrate (referred to as the first substrate) with a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) laminated in this order on one side, and a glass substrate (referred to as the second substrate) without an electrode were prepared. Next, a liquid crystal alignment agent (AL-1) was applied to the electrode-forming surface of the first substrate and one substrate surface of the second substrate using a spinner, and heated (pre-baked) on a hot plate at 80°C for 1 minute. This was followed by drying (post-baking) for 30 minutes in an oven at 230°C with the interior substituted with nitrogen, forming a coating film with an average thickness of 0.1 μm. The resulting coating film was irradiated with 1,000 J / m of linearly polarized ultraviolet light containing a 254 nm emission line using an Hg-Xe lamp. 2The coating film was then irradiated with light from the normal direction of the substrate to perform a photo-alignment treatment. The irradiation dose was measured using an actinometer measuring at a wavelength of 254 nm. The photo-aligned coating film was then heat-treated in a clean oven at 230°C for 30 minutes to form a liquid crystal alignment film. Next, for one of the pair of substrates on which the liquid crystal alignment film was formed, an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was applied by screen printing to the outer edge of the surface having the liquid crystal alignment film. The substrates were then superimposed and pressed together so that the projection directions of the polarization axes on the substrate surfaces during light irradiation were antiparallel, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was filled between the pair of substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive to obtain a liquid crystal cell. Furthermore, to remove flow alignment during liquid crystal injection, the cell was heated at 120°C and then slowly cooled to room temperature. The above series of operations was also performed with a post-baking UV irradiation dose of 100 to 10,000 J / m. 2 Three or more liquid crystal cells with different UV exposure doses were manufactured by changing the exposure dose within the range of , and the liquid crystal cell with the exposure dose that showed the best alignment characteristics (optimum exposure dose) was used for the following evaluation of liquid crystal alignment, initial VHR, VHR reliability, and film strength.

[0108] 3. Evaluation of liquid crystal alignment The liquid crystal cell manufactured in 2 above was set to a 27,000 cd / m 2 The cells were left standing for 500 hours in front of a high-brightness backlight, and the liquid crystal alignment was evaluated by the rate of change in retardation before and after backlight irradiation. First, the retardation of the liquid crystal cell manufactured in 2 above was measured using an Axoscan manufactured by Optoscience, and the rate of change α in retardation before and after backlight irradiation was calculated using the following formula (z-1). The smaller the rate of change α, the better the liquid crystal alignment. A rate of change α of 1% or less was evaluated as "good (○)", a rate of change α of more than 1% and less than 2% was evaluated as "fair (△)", and a rate of change α of more than 2% was evaluated as "poor (×)". α=Δθ / θ1 …(z-1) (In formula (z-1), Δθ represents the difference in retardation before and after irradiation, and θ1 represents the retardation value before irradiation.) As a result, the liquid crystal alignment property of this example was evaluated as "fair (Δ)".

[0109] 4. Evaluation of adhesion to substrate The liquid crystal alignment agent (AL-1) was applied to a glass substrate using a spinner, pre-baked on a hot plate at 80°C for 2 minutes, and then heated (post-baked) for 30 minutes in an oven at 230°C with the interior replaced with nitrogen, forming a coating film with an average thickness of 0.10 μm. By repeating the same procedure, two glass substrates with coating films were produced. On the coating film of one glass substrate with a coating film formed, ODF sealant (S-WB42, manufactured by Sekisui Chemical Co., Ltd.) was applied to a width of 1 mm, and the other glass substrate was bonded so that the coating film and ODF sealant were in contact. After that, a metal halide lamp was used to apply 30,000 J / m 2 After irradiating the film with light (equivalent to 365 nm), the film was heated in an oven at 120°C for 1 hour. After heating, the adhesion strength was measured using a tension and compression tester (model number: SDWS-0201-100SL) manufactured by Imada Seisakusho, and the adhesion of the film to the substrate was evaluated. The evaluation was conducted when the adhesion strength was 200 N / cm 2 If it is above 100N / cm, it is considered "Good (○)" 2 More than 200N / cm 2 If it is less than 100N / cm, it is "Fair (△)". 2 If the adhesive strength was less than 204 N / cm, it was rated as "poor (x)". 2 The adhesion was evaluated as "good (○)."

[0110] 5. Evaluation of film strength (rubbing resistance) The liquid crystal alignment agent (AL-1) prepared in 1 above was applied to a glass substrate using a spinner and heated (pre-baked) on a hot plate at 110°C for 3 minutes. The substrate was then dried (post-baked) for 30 minutes in a nitrogen-purged oven at 230°C to form a coating film with an average thickness of 0.08 μm. The haze value of this coating film was measured using a haze meter. The coating film was then rubbed five times using a rubbing machine equipped with a roll wrapped around a cotton cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / sec, and a pile indentation length of 0.3 mm. The haze value of the liquid crystal alignment film was then measured using a haze meter, and the difference from the haze value before and after rubbing (haze change) was calculated. If the haze value of the film before rubbing is Hz1 (%) and the haze value of the film after rubbing is Hz2 (%), the haze change is expressed by the following formula (z-2): Haze change value (%) = Hz2 - Hz1 ... (z-2) When the haze change value of the liquid crystal alignment film was less than 1.0, it was evaluated as "good (○)", when the haze change value was 1.0 or more and 1.5 or less, it was evaluated as "fair (△)", and when it was more than 1.5, it was evaluated as "poor (×)". If the haze change value is 1.5 or less (more preferably less than 1.0), it can be said that the film strength is sufficiently high and the rubbing resistance is high, that is, the mechanical properties of the film are good. As a result, in this example, the film strength was evaluated as "good (○)".

[0111] 6. Evaluation of film strength (tapping test resistance) The liquid crystal cell manufactured in 2 above was evaluated for its resistance to keystroke tests. The evaluation was performed as follows. First, the liquid crystal cell was observed under a polarizing microscope with crossed Nicols, and the number of bright spots was counted. Next, the liquid crystal cell was fixed on a fixed plate, and a keystroke rod was moved up and down to apply a repeated load to the liquid crystal cell. The load was 250 gf, the number of repetitions was 100,000, and the speed was 10 Hz / sec. After keystrokes, the liquid crystal cell was observed again, and the number of bright spots was counted. If the difference in the number of bright spots before and after keystrokes was less than 10, it was evaluated as "good (○)." If it was 10 to less than 50, it was evaluated as "passable (△)." If it was 50 or more, it was evaluated as "poor (×)." If the difference in the number of bright spots was less than 50 (more preferably less than 10), it can be said that the mechanical strength of the film against keystrokes was good. As a result, in this example, the film strength was evaluated as "good (○)."

[0112] [Examples 2 to 28 and Comparative Examples 1 to 6] A liquid crystal alignment agent was prepared in the same manner as in Example 1, except that the composition of the liquid crystal alignment agent was changed as shown in Table 3. Furthermore, using the obtained liquid crystal alignment agent, an FFS-type liquid crystal cell was produced by a photoalignment method in the same manner as in Example 1, and various evaluations were performed. The results are shown in Table 3. In Example 26, Comparative Example 5, and Comparative Example 6, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane (referred to as compound (N-1)) was blended as an additive component together with the polymer component. In Table 3, the numerical values ​​in the mass ratio column represent the blending ratio (parts by mass) of the solid content of each compound (polymer, additive) relative to 100 parts by mass of the total amount of the polymer components used in preparing the liquid crystal alignment agent.

[0113] [Table 3]

[0114] As shown in Table 3, Examples 1 to 28, which used a liquid crystal alignment agent containing a polymer [A] having a partial structure (a), showed good results in film strength (especially resistance to the keystroke test) and a good balance between film strength, liquid crystal alignment, and adhesion to the substrate, compared to Comparative Examples 1 to 5, which used a liquid crystal alignment agent not containing the polymer [A]. Furthermore, Comparative Example 6, which increased the amount of compound (N-1), a low molecular weight compound having a crosslinkable group, in the alignment agent composition of Comparative Example 5, showed good film strength and adhesion, but was evaluated as having poor liquid crystal alignment.

[0115] Among Examples 1 to 28, the examples (Examples 2 to 11, 13 to 25, 27, and 28) in which a polymer containing an alkylene chain having two or more carbon atoms in the partial structure (a) were used were evaluated as "good (◯)" in liquid crystal alignment, demonstrating that the adhesion of the film and the film hardness (rubbing resistance) can be improved while maintaining the liquid crystal alignment. 1 , B 2 is -O- or -NR 2 The examples using the polymers of - (Examples 1, 2, 4, 5, 8 to 28) were rated as "good (◯)" in film strength (durability to keystroke test), and were more excellent.

[0116] [Example 29: Rubbed FFS-type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent The solution of the polymer (PAA-4) obtained in Synthesis Example 4 was diluted with NMP and butyl cellosolve (BC) to obtain a solution with a solvent composition of NMP / BC=80 / 20 (mass ratio) and a solid content concentration of 3.5 mass %. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-35).

[0117] 2. Fabrication of FFS-type LCD elements using the rubbing method A glass substrate (referred to as the first substrate) with a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) laminated in this order on one side thereof, and a glass substrate (referred to as the second substrate) without an electrode, were prepared. Next, a liquid crystal alignment agent (AL-35) was applied to the electrode-formed surface of the first substrate and one side of the second substrate using a spinner and heated (pre-baked) on a hot plate at 110°C for 3 minutes. This was then dried (post-baked) for 30 minutes in a nitrogen-purged oven at 230°C to form a coating film with an average thickness of 0.08 μm. The coating film surface was then rubbed using a rubbing machine equipped with a roll wrapped around a rayon cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / sec, and a pile depth of 0.3 mm. This was followed by ultrasonic cleaning in ultrapure water for 1 minute and then drying in a clean oven at 100°C for 10 minutes to obtain a pair of substrates with liquid crystal alignment films. Next, a pair of substrates with liquid crystal alignment films were screen-printed with an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres, leaving a liquid crystal injection port at the edge of the surface where the liquid crystal alignment film was formed. The substrates were then stacked and pressed together, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was injected into the gap between the pair of substrates through the liquid crystal injection port, and the liquid crystal injection port was then sealed with an epoxy adhesive. To eliminate flow alignment during liquid crystal injection, the substrates were heated to 120°C and then slowly cooled to room temperature to produce a liquid crystal cell. When stacking the pair of substrates, the rubbing directions of each substrate were antiparallel.

[0118] 3. Evaluation The liquid crystal alignment property of the liquid crystal cell produced in 2 above was evaluated in the same manner as in Example 1. In addition, the liquid crystal alignment agent (AL-35) was used to evaluate the adhesion and film strength in the same manner as in Example 1. The evaluation results are shown in Table 4.

[0119] [Examples 30 to 39 and Comparative Examples 7 to 11] A liquid crystal alignment agent was prepared in the same manner as in Example 29, except that the composition of the liquid crystal alignment agent was changed as shown in Table 4. Furthermore, using the obtained liquid crystal alignment agent, an FFS-type liquid crystal cell was produced by the rubbing method in the same manner as in Example 29, and various evaluations were performed. The results are shown in Table 4. In Examples 31 to 37, Example 39, and Comparative Examples 10 and 11, two types of polymers were used as the polymer component. In Table 4, the numerical values ​​in the mass ratio column represent the blending ratio (parts by mass) of the solid content of each compound (polymer, additive) relative to 100 parts by mass of the total amount of the polymer components used in preparing the liquid crystal alignment agent.

[0120] [Table 4]

[0121] As shown in Table 4, Examples 29 to 39, which used a liquid crystal alignment agent containing the polymer [A] having the partial structure (a), showed better results in film strength (especially resistance to the keystroke test) than Comparative Examples 7 to 11, which used a liquid crystal alignment agent not containing the polymer [A]. Furthermore, Examples 29 to 39 also showed good liquid crystal alignment properties and adhesion to the substrate.

[0122] [Example 40: PSA type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent A solution containing 5 parts by mass of the polymer (PSQ-1) obtained in Synthesis Example 40 and a solution containing 95 parts by mass of the polymer (PI-7) obtained in Synthesis Example 34 were mixed and diluted with NMP and BC to obtain a solution with a solvent composition of NMP / BC=50 / 50 (mass ratio) and a solids concentration of 3.5% by mass. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-51).

[0123] 2. Preparation of Liquid Crystal Composition 5% by mass of a liquid crystal compound represented by the following formula (L1-1) and 0.3% by mass of a photopolymerizable compound represented by the following formula (L2-1) were added to 10 g of nematic liquid crystal (MLC-6608, manufactured by Merck) and mixed to obtain liquid crystal composition LC1. [ka]

[0124] 3. Manufacturing of PSA type liquid crystal display elements The liquid crystal alignment agent (AL-51) prepared above was applied to the transparent electrode surface of a glass substrate with an ITO transparent electrode using a spinner. The substrate was prebaked on a hot plate at 80°C for 1 minute, and then heated in a nitrogen-purged oven at 200°C for 1 hour to remove the solvent, forming a 0.08 μm-thick coating (liquid crystal alignment film). This coating film was then rubbed using a rubbing machine equipped with a roll wrapped around a rayon cloth at a roll rotation speed of 400 rpm, a stage movement speed of 3 cm / sec, and a pile depth of 0.1 mm. The substrate was then ultrasonically cleaned in ultrapure water for 1 minute and then dried in a clean oven at 100°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. This process was repeated to obtain a pair (two substrates) with a liquid crystal alignment film. Note that this rubbing treatment was weak, intended to suppress liquid crystal collapse and facilitate alignment division. An epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was applied by screen printing to the outer periphery of the surface of one of the substrates bearing the liquid crystal alignment film, and then the liquid crystal alignment film surfaces of the pair of substrates were placed facing each other, overlapped, and pressed together, followed by heating at 150°C for 1 hour to thermally cure the adhesive. Next, liquid crystal composition LC1 was filled into the gap between the substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. To prevent flow alignment during liquid crystal injection, the resulting mixture was heated at 150°C for 10 minutes and then slowly cooled to room temperature. Next, an AC voltage of 10 V at a frequency of 60 Hz was applied between the electrodes of the obtained liquid crystal cell, and while the liquid crystal was in a driving state, ultraviolet rays of 50,000 J / m were irradiated using an ultraviolet irradiation device that used a metal halide lamp as a light source. 2 The irradiation amount was measured using an actinometer measuring at a wavelength of 365 nm as a reference. A PSA liquid crystal cell was thus produced.

[0125] 4. Evaluation The liquid crystal cell produced in 3 above was evaluated for liquid crystal alignment, adhesion, and film strength in the same manner as in Example 1. Table 5 shows the evaluation results.

[0126] [Comparative Example 12] A liquid crystal alignment agent was prepared in the same manner as in Example 40, except that the composition of the liquid crystal alignment agent was changed as shown in Table 5. In addition, a PSA-type liquid crystal cell was produced using the obtained liquid crystal alignment agent in the same manner as in Example 40, and various evaluations were performed. The evaluation results are shown in Table 5. In Table 5, the numerical values ​​in the mass ratio column represent the blending ratio (parts by mass) of the solid content of each compound (polymer, additive) relative to 100 parts by mass of the total amount of the polymer components used in preparing the liquid crystal alignment agent.

[0127] [Table 5]

[0128] As shown in Table 5, Example 40, which used a liquid crystal alignment agent containing polymer [A], was evaluated as good in terms of liquid crystal alignment property, adhesion, and film strength. In contrast, Comparative Example 12, which used a liquid crystal alignment agent not containing polymer [A], was evaluated as "fair" in terms of adhesion and film strength (rubbing resistance), and as "poor" in terms of film strength (tapping test resistance).

[0129] [Example 41: Optical VA type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent A solution containing 30 parts by mass of the polymer (MI-1) obtained in Synthesis Example 41 and 70 parts by mass of the polymer (PAA-2) obtained in Synthesis Example 2 was mixed and diluted with NMP and BC to obtain a solution with a solvent composition of NMP / BC=80 / 20 (mass ratio) and a solids concentration of 3.5% by mass. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-53).

[0130] 2. Manufacturing of optical VA type liquid crystal display elements The liquid crystal alignment agent (AL-53) prepared above was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a spinner, and pre-baked on a hot plate at 80°C for 1 minute. It was then heated at 230°C for 1 hour in an oven with the interior replaced with nitrogen, forming a coating film with a thickness of 0.1 μm. Next, the surface of this coating film was irradiated with polarized ultraviolet light at 1,000 J / m², including a 313 nm emission line, using an Hg-Xe lamp and a Glan-Taylor prism. 2 The substrate was irradiated with light from a direction tilted by 40° from the normal to the substrate to impart liquid crystal alignment ability. The same procedure was repeated to prepare a pair (two substrates) having a liquid crystal alignment film. An epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was screen-printed onto the outer periphery of the surface of one of the substrates bearing the liquid crystal alignment film. The pair of substrates were then placed with the liquid crystal alignment film surfaces facing each other and pressed together so that the UV light axes of the substrates were antiparallel to each other. The adhesive was then thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was injected into the gap between the substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. To eliminate flow alignment during liquid crystal injection, the substrate was heated to 130°C and then slowly cooled to room temperature.

[0131] 3. Evaluation The liquid crystal cell produced in 2 above was evaluated for liquid crystal alignment, adhesion, and film strength in the same manner as in Example 1. Table 6 shows the evaluation results.

[0132] [Comparative Example 13] A liquid crystal alignment agent was prepared in the same manner as in Example 4, except that the composition of the liquid crystal alignment agent was changed as shown in Table 6. In addition, an optical VA-type liquid crystal cell was produced using the obtained liquid crystal alignment agent in the same manner as in Example 41, and various evaluations were performed. The results are shown in Table 6. In Table 6, the numerical values ​​in the mass ratio column represent the blending ratio (parts by mass) of the solid content of each compound (polymer, additive) relative to 100 parts by mass of the total amount of the polymer components used in preparing the liquid crystal alignment agent.

[0133] [Table 6]

[0134] As shown in Table 6, Example 41, which used a liquid crystal alignment agent containing polymer [A], was evaluated as good in terms of liquid crystal alignment property, adhesion, and film strength. In contrast, Comparative Example 13, which used a liquid crystal alignment agent not containing polymer [A], was evaluated as "fair" in terms of film strength (rubbing resistance) and "poor" in terms of film strength (tapping test resistance).

[0135] From the above results, it was revealed that a liquid crystal alignment agent containing a polymer [A] having a partial structure (a) can obtain a liquid crystal element with excellent liquid crystal alignment properties, and can also form a liquid crystal alignment film with high adhesion and film strength.

Claims

1. The polymer [A] contains a partial structure (a) represented by the following formula (1): The polymer [A] contains a structural unit derived from a diamine having the partial structure (a) (where m in the following formula (1) is 0 or 1), The diamine is a compound represented by the following formula (2) (wherein each partial structure represented by the following formula (1) in the following formula (2) has “—CH ２ OR １ The number of groups represented by " is 1 or 2. 【Chemistry 1】 (In formula (1), A １ , A ２ and A ３ are each independently a divalent aromatic ring group, and m is an integer of 0 to 2. However, when m is 0, A １ and A ３ At least one of the divalent aromatic ring groups represented by "-CH ２ OR １ " is bonded to an aromatic ring, and when m is 1 or 2, A １ , A ２ and A ３ At least one of the divalent aromatic ring groups represented by "-CH ２ OR １ " is bonded to an aromatic ring. １ is a hydrogen atom or a monovalent organic group. １ and B ２ are each independently —O—, —S—, or —NR ２ -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR ２ -CO-, -CO-NR ２ -, -NR ２ -CO-NR ３ or an alkanediyl group having 1 to 14 carbon atoms, or an alkanediyl group having 2 to 14 carbon atoms in which any methylene group is —O—, —S—, —NR ２ -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR ２ -CO-, -CO-NR ２ - and -NR ２ -CO-NR ３ - is a divalent group substituted with at least one of R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group. ２ are the same or different, and multiple B ２ are the same or different. "*" represents a bond.) 【Chemistry 2】 (In formula (2), A １ , A ２ , A ３ , B １ and B ２ has the same meaning as in formula (1). m is 0 or 1. D １ and D ２ are each independently a single bond or a divalent chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a nitrogen-containing heterocyclic group.

2. B in the above formula (1) １ and B ２ Among them, "-CH ２ OR １ " is bonded to an aromatic ring, and the group adjacent to the divalent aromatic ring group is "-CH ２ OR １ " is bonded to an aromatic ring having a group represented by -O-, -S-, -NR ２ -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR ２ -CO-, -CO-NR ２ -or-NR ２ -CO-NR ３ The liquid crystal aligning agent according to claim 1, wherein the bond is -.

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

4. The liquid crystal aligning agent according to claim 1 , further comprising a polymer [Q] that does not have the partial structure (a).

5. The liquid crystal aligning agent according to claim 4, wherein the polymer [Q] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer.

6. A liquid crystal alignment film formed by the liquid crystal aligning agent according to any one of claims 1 to 5.

7. A liquid crystal device comprising the liquid crystal alignment film according to claim 6 .

8. A polyamic acid, polyamic acid ester, or polyimide, which contains a structural unit derived from a diamine having a partial structure represented by the following formula (1) (wherein m in the following formula (1) is 0 or 1), The diamine is a compound represented by the following formula (2) (wherein each partial structure represented by the following formula (1) in the following formula (2) has “—CH ２ OR １ " is 1 or 2. 【Transformation 3】 (In formula (1), A １ , A ２ and A ３ are each independently a divalent aromatic ring group, and m is an integer of 0 to 2. However, when m is 0, A １ and A ３ At least one of the divalent aromatic ring groups represented by "-CH ２ OR １ " is bonded to an aromatic ring, and when m is 1 or 2, A １ , A ２ and A ３ At least one of the divalent aromatic ring groups represented by "-CH ２ OR １ " is bonded to an aromatic ring. １ is a hydrogen atom or a monovalent organic group. １ and B ２ are each independently —O—, —S—, or —NR ２ -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR ２ -CO-, -CO-NR ２ -, -NR ２ -CO-NR ３ or an alkanediyl group having 1 to 14 carbon atoms, or an alkanediyl group having 2 to 14 carbon atoms in which any methylene group is —O—, —S—, —NR ２ -, -CO-, -CO-O-, -O-CO-, -CS-O-, -O-CS-, -NR ２ -CO-, -CO-NR ２ - and -NR ２ -CO-NR ３ - is a divalent group substituted with at least one of R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group. ２ are the same or different, and multiple B ２ are the same or different. "*" represents a bond.) 【Chemistry 4】 (In formula (2), A １ , A ２ , A ３ , B １ and B ２ has the same meaning as in formula (1). m is 0 or 1. D １ and D ２ are each independently a single bond or a divalent chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a nitrogen-containing heterocyclic group.

Images