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

Abstract

To provide a liquid crystal alignment agent with which a liquid crystal element superior in liquid crystal alignment and a voltage holding rate can be obtained.SOLUTION: There is provided a liquid crystal alignment agent which includes a polymer (P) having at least one kind selected from a group consisting of a partial structure represented by a formula (1) and a partial structure represented by a formula (2). In the formulas, X1 is a tetravalent organic group. X2 is a divalent organic group represented by a formula (3). At least one of A1 and A2 is a divalent heterocyclic aromatic group having a nitrogen atom. Y1 and Y2 are "-NR4-" etc. R3 is a divalent organic group obtained by substituting -NR5CO- etc., for at least one arbitrary methylene group of a C2-20 divalent saturated aliphatic hydrocarbon group.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] Liquid crystal elements are widely used in televisions, mobile devices, various monitors, etc. As their uses become more diverse, there is a demand for even higher quality liquid crystal elements, and progress is being made in improving the liquid crystal alignment film, which is one of the constituent materials of liquid crystal elements, as well as improving the driving method and element structure (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses that by incorporating a polyamic acid obtained by reacting a diamine compound containing a nitrogen-containing diamine such as N,N'-bis(2-((5-aminopyridin-2-yl)amino)ethyl)urea with a tetracarboxylic dianhydride into a liquid crystal alignment agent, the photoreactivity and rubbing resistance of the coating film, liquid crystal alignment properties, AC image retention characteristics, and voltage holding ratio can be improved in a well-balanced manner. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-200439 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to satisfy the recent demand for higher definition, liquid crystal elements are required to have further improvements in liquid crystal alignment properties and voltage holding ratio.

[0006] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a liquid crystal aligning agent which can provide a liquid crystal device having excellent liquid crystal alignment properties and voltage holding ratio. [Means for solving the problem]

[0007] The present invention employs the following means to solve the above problems.

[0008] <1> A liquid crystal aligning agent comprising a polymer (P) having at least one selected from the group consisting of a partial structure represented by the following formula (1) and a partial structure represented by the following formula (2): [ka] (In formula (1) and formula (2), X 1 is a tetravalent organic group. 2 R is a divalent organic group represented by the following formula (3). 1 and R 2 are each independently a hydrogen atom or a monovalent organic group having 1 to 6 carbon atoms. [ka] (In formula (3), A 1 and A 2 are each independently a divalent aromatic group. 1 and A 2 At least one of the groups is a divalent heterocyclic aromatic group having a nitrogen atom. Y 1 and Y 2 each independently represents a single bond, -O-, -S-, or -NR 4 -", "-COO-", "-NR 4 -CO-" or a divalent group having a nitrogen-containing non-aromatic heterocycle. R 3 At least one arbitrary methylene group in the divalent saturated aliphatic hydrocarbon group having 2 to 20 carbon atoms is selected from "-O-", "-S-", and the following formulae (4) to (10): [ka] is a divalent organic group substituted with at least one of the groups represented by the following formula: 3 R contains at least one kind of group represented by each of the above formulas (4) to (10). 3In the formula (4), "-O-", "-S-", and the groups represented by the above formulae (4) to (10) are not adjacent to each other, and the two bonds of "-O-", "-S-", and the groups represented by the above formulae (4) to (10) are each bonded to a carbon atom constituting a hydrocarbon group, a nitrogen-containing non-aromatic heterocycle, or a nitrogen-containing aromatic heterocycle. R 4 and R 5 are each independently a hydrogen atom or a monovalent organic group, or R 4 and R 5 and are combined together to form R 4 The nitrogen atom to which R is bonded 5 R represents a ring structure formed together with the nitrogen atom to which it is bonded. 6 , R 7 and R 8 are each independently a hydrogen atom or a monovalent organic group. However, R 3 When Y contains any one of the divalent groups represented by the above formulas (5) to (7), 1 , Y 2 and R 3 At least one of them has a protecting group for the polar functional group. A 3 is a divalent heterocyclic aromatic group having a nitrogen atom. "*" indicates a bond.

[0009] <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 the liquid crystal alignment film. <4> A polymer having at least one member selected from the group consisting of a partial structure represented by the above formula (1) and a partial structure represented by the above formula (2). <5> A compound represented by the following formula (22): [ka] (In formula (22), A 1 , A 2 , Y 1 , Y 2 and R 3 is the same as the above formula (3). Effect of the Invention

[0010] According to the liquid crystal aligning agent of the present invention, a liquid crystal element having good liquid crystal alignment and voltage holding ratio can be obtained. In particular, even when the liquid crystal element is driven for a long time, it is possible to obtain a liquid crystal element that is less likely to cause AC afterimages and can maintain a high voltage holding ratio. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, each component contained in the liquid crystal aligning agent of the present disclosure and other components that are optionally blended as necessary will be described.

[0012] In this specification, the term "hydrocarbon group" includes chain-like hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The term "chain-like hydrocarbon group" refers to a straight-chain hydrocarbon group and a branched hydrocarbon group that do not include a cyclic structure in the main chain and are composed only of a chain structure. However, they may be saturated or unsaturated. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that includes only an alicyclic hydrocarbon structure as a ring structure and does not include an aromatic ring structure. However, it does not have to be composed only of an alicyclic hydrocarbon structure, and it also includes those that have a chain structure as a part of it. The term "aromatic hydrocarbon group" refers to a hydrocarbon group that includes an aromatic ring structure as a ring structure. However, it does not have to be composed only of an aromatic ring structure, and it may include a chain structure or an alicyclic hydrocarbon structure as a part of it.

[0013] The term "saturated aliphatic hydrocarbon group" includes saturated linear hydrocarbon groups and saturated alicyclic hydrocarbon groups. The term "aromatic group" refers to a group obtained by removing n hydrogen atoms (n is an integer) from a substituted or unsubstituted aromatic hydrocarbon ring or a ring portion of a substituted or unsubstituted aromatic heterocycle. However, when the aromatic group has multiple rings, it includes a group obtained by removing n hydrogen atoms from the same ring and a group obtained by removing n hydrogen atoms from different rings. The term "heterocyclic aromatic group" refers to a group obtained by removing n hydrogen atoms (n is an integer) from a ring portion of an aromatic heterocycle. However, when the heterocyclic aromatic group has multiple rings, it includes a group obtained by removing n hydrogen atoms from the same ring and a group obtained by removing n hydrogen atoms from different rings. The term "protecting group" refers to an atomic group that temporarily converts a highly reactive characteristic group into an inactive functional group.

[0014] The liquid crystal aligning agent of the present disclosure contains a polymer (P) having at least one selected from the group consisting of a partial structure represented by the following formula (1) and a partial structure represented by the following formula (2). [ka] (In formula (1) and formula (2), X 1 is a tetravalent organic group. 2 R is a divalent organic group represented by the following formula (3). 1 and R 2 are each independently a hydrogen atom or a monovalent organic group having 1 to 6 carbon atoms. [ka] (In formula (3), A 1 and A 2 are each independently a divalent aromatic group. 1 and A 2 At least one of the groups is a divalent heterocyclic aromatic group having a nitrogen atom. Y 1 and Y 2 each independently represents a single bond, -O-, -S-, or -NR 4 -", "-COO-", "-NR 4-CO-" or a divalent group having a nitrogen-containing non-aromatic heterocycle. R 3 At least one arbitrary methylene group in the divalent saturated aliphatic hydrocarbon group having 2 to 20 carbon atoms is selected from "-O-", "-S-", and the following formulae (4) to (10): [ka] is a divalent organic group substituted with at least one of the groups represented by the following formula: 3 R contains at least one kind of group represented by each of the above formulas (4) to (10). 3 In the formula (4), "-O-", "-S-" and the groups represented by the formulae (4) to (10) are not adjacent to each other, and the two bonds of "-O-", "-S-" and the groups represented by the formulae (4) to (10) are each bonded to a carbon atom constituting a hydrocarbon group, a nitrogen-containing non-aromatic heterocycle or a nitrogen-containing aromatic heterocycle. 4 and R 5 are each independently a hydrogen atom or a monovalent organic group, or R 4 and R 5 and are combined together to form R 4 The nitrogen atom to which R is bonded 5 R represents a ring structure formed together with the nitrogen atom to which it is bonded. 6 , R 7 and R 8 are each independently a hydrogen atom or a monovalent organic group. 3 When Y contains any one of the divalent groups represented by the above formulas (5) to (7), 1 , Y 2 and R 3 At least one of the above has a protecting group for a polar functional group. 3 is a divalent heterocyclic aromatic group having a nitrogen atom. "*" indicates a bond.

[0015] In the above formula (1) and formula (2), X 1is a tetravalent organic group derived from a tetracarboxylic acid derivative. In this specification, the term "tetracarboxylic acid derivative" includes tetracarboxylic acid dianhydrides, tetracarboxylic acid diesters, and tetracarboxylic acid diester dihalides.

[0016] X 1 As the tetracarboxylic acid derivative constituting X, a compound known as a tetracarboxylic acid derivative that can be used in the production of polyamic acid, polyamic acid ester, and polyimide can be used. From the viewpoints of availability of the compound, ease of production of the polymer, etc., X 1 is preferably a tetravalent group represented by any one of the following formulas (14) to (21). When a liquid crystal alignment film is obtained by a photoalignment method, X 1 is preferably a tetravalent group having a cyclobutane ring structure, and specifically, is particularly preferably a tetravalent group represented by the following formula (14) or formula (15). [ka] (In formulas (14) to (21), "*" indicates a bond.)

[0017] In the above formula (1) and formula (2), X 2 is a divalent organic group derived from a diamine compound having a partial structure represented by the above formula (3) (hereinafter, also referred to as a "specific diamine"). In the above formula (3), A 1 and A 2 At least one of the groups is a divalent heterocyclic aromatic group having a nitrogen atom. Examples of the divalent heterocyclic aromatic group having a nitrogen atom include a divalent group having a nitrogen-containing aromatic heterocycle such as a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, an oxazole ring, a thiazole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an indole ring, a benzimidazole ring, a benzoxazole ring, a benzothiazole ring, a purine ring, a quinoline ring, a carbazole ring, or a bipyridine ring. 1 and A 2In the heterocyclic aromatic group, a substituent may be introduced into the nitrogen-containing aromatic heterocycle. Examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a protecting group, and a hydroxy group.

[0018] A 1 and A 2 When only one of the groups is a divalent heterocyclic aromatic group having a nitrogen atom, specific examples of the other group include a divalent group having an aromatic hydrocarbon ring or an aromatic heterocycle, such as a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, or a fluorene ring. A 1 and A 2 From the viewpoint of ease of synthesis, among the above, a divalent group having a benzene ring or a pyridine ring is preferable, and a phenylene group, a pyridylene group, a biphenylene group, or a bipyridylene group is more preferable. Also, from the viewpoint of electrical properties, a structure having basicity is preferable, a divalent group having a pyridine ring, an imidazole ring, or a benzimidazole ring is more preferable, a divalent group having a pyridine ring is further preferable, and a pyridylene group is particularly preferable.

[0019] Y 1 and Y 2 each independently represents a single bond, -O-, -S-, or -NR 4 -", "-COO-" or "-NR 4 Y is a divalent group having a nitrogen-containing non-aromatic heterocycle. 1 and Y 2 In the above, examples of the divalent group having a nitrogen-containing non-aromatic heterocycle include a piperidine-1,4-diyl group, a piperazine-1,4-diyl group, -CO-B 1 -(However, B 1 is a piperidine-1,4-diyl group or a piperazine-1,4-diyl group). Y 1 and Y 2 is X in the above formula (1) and formula (2). 1 has a cyclobutane ring structure, from the viewpoint of enhancing the photoreactivity of the polymer (P), 1, Y 2 ) is preferably an electron donating group that increases the electron density of "-O-", "-S-", "-NR 4 -" or piperidine-1,4-diyl group is more preferred, and "-NR 4 It is more preferably "-" or "-O-".

[0020] -NR 4 -" in R 4 is a hydrogen atom or a monovalent organic group, or R 5 and are combined together, R 4 The nitrogen atom to which R is bonded 5 forms a ring structure together with the nitrogen atom to which it is bonded. Examples of such ring structures include piperazine-1,4-diyl groups. From the viewpoint of increasing the solubility of the polymer (P), R 4 is preferably a protecting group or a monovalent saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, more preferably a protecting group or an alkyl group having 1 to 3 carbon atoms, and more preferably a protecting group.

[0021] R 4 When R is a protecting group, the protecting group is preferably a leaving group which is removed by at least one of heat and light, and more preferably a thermally removable group. 4 When is a thermally detachable group, the protective group can be detached in the process of forming a liquid crystal alignment film by applying a liquid crystal alignment agent to a substrate and heating it. Therefore, it is not necessary to provide a separate step for deprotection, which is preferable in that the process can be simplified. From the viewpoint of deprotection in the process of forming a liquid crystal alignment film, it is particularly preferable that the thermally detachable group is a group that decomposes at a temperature of 120 to 300°C and is replaced with a hydrogen atom.

[0022] R 3 R is a divalent organic group in which at least one arbitrary methylene group in a divalent saturated aliphatic hydrocarbon group having 2 to 20 carbon atoms is replaced with at least one of "-O-", "-S-" and the groups represented by each of the above formulas (4) to (10). 3In the above, from the viewpoint of the liquid crystal alignment property of the polymer (P), the divalent aliphatic hydrocarbon group is preferably a monovalent chain hydrocarbon group, more preferably an alkylene group having 2 to 12 carbon atoms, still more preferably an alkylene group having 4 to 12 carbon atoms, and particularly preferably an alkylene group having 4 to 8 carbon atoms.

[0023] R 3 contains at least one of the groups represented by the above formulas (4) to (10) (hereinafter also referred to as "specific nitrogen-containing groups") in total. 3 Specific examples of the divalent heterocyclic aromatic group having a nitrogen atom include A 1 and A 2 Among these, the groups A 3 From the viewpoint of electrical properties and mechanical properties, A is preferably a divalent group having a pyridine ring, a pyrimidine ring, a triazine ring, an imidazole ring, a benzimidazole ring, or a purine ring and forming a hydrogen bond between molecules. Among these, from the viewpoint of ease of synthesis and electrical properties, a divalent group having a pyridine ring is more preferable, and a pyridylene group is particularly preferable. 3 may have a substituent in the heterocyclic moiety. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms and a hydroxy group.

[0024] From the viewpoint of the solubility of the polymer (P), R 3 The specific nitrogen-containing group of R is preferably a group represented by any one of the above formulas (4) and (8) to (10). From the viewpoint of the electrical properties of the polymer (P), 3 The specific nitrogen-containing group contained in R is preferably a group represented by any one of the above formulas (4) to (7). 3 The number of specific nitrogen-containing groups in R is not particularly limited, and can be appropriately set depending on the type of specific nitrogen-containing group, etc. 3 When the specific nitrogen-containing group contained in R is a group represented by the above formula (4), the number of specific nitrogen-containing groups is preferably 2 or more, and more preferably 2 or 3. 3When the specific nitrogen-containing group contained in is a group represented by any one of the above formulas (5) to (10), the number of specific nitrogen-containing groups is preferably one.

[0025] R 3 By virtue of the above structure, when a liquid crystal alignment film is formed by a rubbing method, it is possible to promote the stretching of the molecular chains of the polymer (P) during the rubbing treatment. Furthermore, when a liquid crystal alignment film is formed by a photo-alignment method, it is possible to promote the thermal rearrangement (self-organized anisotropic amplification) of the molecular chains of the polymer (P) during the heat treatment after exposure. This makes it possible to obtain a liquid crystal alignment film having excellent liquid crystal alignment properties. Furthermore, R 3 The specific nitrogen-containing group of the above-mentioned formula R forms a hydrogen bond between molecules, thereby making it possible to obtain a liquid crystal alignment film having excellent mechanical properties and electrical properties. 3 In the formula, each of the two bonds in the specific nitrogen-containing group is a hydrocarbon group. 、 It is bonded to a carbon atom constituting a nitrogen-containing non-aromatic heterocycle or a nitrogen-containing aromatic heterocycle. That is, R 3 The two bonds of the specific nitrogen-containing group are bonded only to carbon atoms constituting a hydrocarbon group, a nitrogen-containing non-aromatic heterocycle or a nitrogen-containing aromatic heterocycle.

[0026] R 5 , R 6 , R 7 and R 8 From the viewpoint of increasing the solubility of the polymer (P), the monovalent organic group in is preferably a protecting group or a monovalent saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, more preferably a protecting group or an alkyl group having 1 to 3 carbon atoms, and further preferably a protecting group. 4 The explanation of the protecting group in the above can be used.

[0027] X 2 It is preferable that X has a protecting group for the polar functional group. 2The protecting group of the polar functional group of X may be a protecting group such as an amino group, a hydroxyl group, or a carboxyl group. The protecting group is preferably a removable group that is removable by at least one of heat and light, and more preferably a thermally removable group. From the viewpoint of removing the protecting group during the process of forming the liquid crystal alignment film, 2 It is particularly preferable that the protecting group for the polar functional group contained in is a group that decomposes at a temperature of 120 to 300° C. and is replaced with a hydrogen atom.

[0028] From the viewpoint of improving electrical properties, X 2 It is preferable that X has a functional group for inactivating at least one selected from the group consisting of an amino group, an amide group, a urea bond, an oxalyldiamide bond, and a diacylhydrazide bond as a protecting group for the polar functional group. For example, X 2 contains a protecting group for the amino group, a basic primary or secondary amine is generated by an elimination reaction, which is expected to promote the imidization reaction of the polyamic acid, capture acidic impurities present in the liquid crystal, form non-covalent crosslinks between molecules, etc.

[0029] X 2 When A has a protecting group for a polar functional group, 1 , A 2 , Y 1 , Y 2 and R 3 Any of X may have a protecting group for a polar functional group. 2 The number of protecting groups in R 3 When Y contains any of the divalent groups represented by the above formulas (5) to (7), 1 , Y 2 and R 3 At least one of R 4 ~R 8 At least one of the groups is a protecting group. In order to increase the solubility of the polymer (P) in the liquid crystal alignment agent and to improve the electrical properties after the liquid crystal alignment film is formed, X 2 It is preferable that X has two or more protecting groups for polar functional groups.2 In the above, the number of protective groups for the polar functional groups is preferably 4 or less from the viewpoints of ease of production of the polymer (P) and the mechanical properties of the liquid crystal alignment film.

[0030] Specific examples of the thermally detachable group include a methoxycarbonyl group, a trifluoromethoxycarbonyl group, an ethoxycarbonyl group, a n-propoxycarbonyl group, a isopropoxycarbonyl group, a n-butoxycarbonyl group, a tert-butoxycarbonyl group, a sec-butoxycarbonyl group, a n-pentyloxycarbonyl group, a n-hexyloxycarbonyl group, a 9-fluorenylmethoxycarbonyl group, etc. Among these, a structure in which the elimination reaction proceeds efficiently at the baking temperature of the liquid crystal alignment film (preferably 120 to 300° C.) is preferred, a tert-butoxycarbonyl group or a 9-fluorenylmethoxycarbonyl group is more preferred, and a tert-butoxycarbonyl group (Boc group) is particularly preferred.

[0031] X 2 In the above, A 1 , A 2 , Y 1 , Y 2 and R 3 X is a divalent group formed by appropriately combining the groups exemplified in the explanation of each of the above. X is a divalent group formed by appropriately combining the groups exemplified in the explanation of each of the above. X is a divalent group formed by appropriately combining the groups exemplified in the explanation of each of the above. 2 is preferably a group represented by the following formula (11), a group represented by the following formula (12), or a group represented by the following formula (13). [ka] (In formulas (11) to (13), Y 3 and Y 4 are each independently "* 1 -NR 9 -CO-" or "-NR 9 -CO-* 1 " * 1 " is "-(CH2) r -" indicates a bond with R 9 , R 10 , R 11 , R12 , R 13 and R 14 are each independently a hydrogen atom or a monovalent organic group. 1 , Y 2 , R 10 and R 11 At least one of the above has a protecting group for a polar functional group. r is an integer of 1 to 6. s and t are each independently an integer of 0 to 6, provided that 1≦r+s+t≦12 is satisfied. v, w, e and f are each independently an integer of 1 to 6. u is an integer of 0 to 2. A 1 , A 2 , Y 1 , and Y 2 is the same as in formula (3) above. "*" indicates a bond.)

[0032] In the above formulas (11) to (13), R 9 , R 10 , R 11 , R 12 , R 13 and R 14 Specific examples and preferred examples of the monovalent organic group are described above in R 4 The explanation given in the above can be used. From the viewpoint of improving the liquid crystal alignment of the liquid crystal element, s and t are preferably 1 or more, and more preferably 2 or more. From the viewpoint of ensuring the electrical characteristics of the liquid crystal element, s and t are preferably 4 or less. r is preferably 1 to 4.

[0033] Each of v, w, e and f is preferably 2 or more from the viewpoint of enhancing the liquid crystal alignment property of a liquid crystal element, and is preferably 4 or less from the viewpoint of ensuring the electrical characteristics of the liquid crystal element. A 1 , A 2 , Y 1 , and Y 2 Regarding A in the above formula (3), 1 , A 2 , Y 1 , and Y 2 The explanations of specific examples and preferred examples of the above can be cited.

[0034] X 2is particularly preferably a divalent group represented by the following formula (11-1) or a divalent group represented by the following formula (12-1), since it is highly effective in improving the liquid crystal alignment (particularly reducing AC image retention) and electrical characteristics (particularly long-term reliability) of a liquid crystal element. Note that AC image retention is an image retention caused by the application of an AC voltage, and is caused by the initial alignment direction of the liquid crystal shifting from the direction at the time of manufacture as the liquid crystal element is driven for a long period of time. [ka] (In formula (11-1) and formula (12-1), R 15 , R 16 , R 17 and R 18 are each independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, or a thermally detachable group. 15 , R 16 , R 17 and R 18 At least one of the groups is a thermally detachable group. p is an integer of 1 to 4. "*" indicates a bond.)

[0035] In the above formula (11-1), from the viewpoints of the solubility of the polymer (P), the liquid crystal alignment property, and the voltage holding ratio, R 15 , R 16 , R 17 and R 18 At least one of R is preferably a thermally detachable group, and more preferably two or more of R are thermally detachable groups. 15 , R 16 , R 17 and R 18 It is preferable that two or more of the groups are thermally detachable groups.

[0036] The polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. The polymer (P) has a partial structure derived from a tetracarboxylic acid derivative and a partial structure derived from a specific diamine. The synthesis method of the polymer (P) is not particularly limited, and the polymer (P) can be obtained by appropriately combining standard methods in organic chemistry.

[0037] <Polyamic acid> When the polymer (P) is a polyamic acid, the polyamic acid (hereinafter also referred to as "polyamic acid (P)") can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine compound containing a specific diamine.

[0038] (Tetracarboxylic acid dianhydride) The tetracarboxylic dianhydride used in the synthesis of the polyamic acid (P) is not particularly limited, but examples thereof include aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aromatic tetracarboxylic dianhydrides.

[0039] Specific examples of these include aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride and ethylenediaminetetraacetic dianhydride; Examples of alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5, 9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclohexanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, etc.; Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, p-phenylene bis(trimellitic monoester anhydride), ethylene glycol bis(anhydrotrimellitate), 1,3-propylene glycol bis(anhydrotrimellitate), 3,3',4,4'-benzophenone tetracarboxylic dianhydride, and 4,4'-biphthalic dianhydride; in addition, the tetracarboxylic dianhydrides described in JP-A-2010-97188 can be used.

[0040] Among the above, the tetracarboxylic dianhydride used in the synthesis of the polyamic acid (P) is preferably at least one compound selected from the group consisting of 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, pyromellitic dianhydride, and 4,4'-biphthalic dianhydride (hereinafter also referred to as "specific acid anhydride"), in terms of being able to improve liquid crystal alignment properties and electrical properties in combination with a specific diamine.

[0041] When a specific acid anhydride is used in the synthesis of the polyamic acid (P), the proportion of the specific acid anhydride used is preferably 10 mol% or more based on the total amount of the tetracarboxylic dianhydride used in the synthesis. More preferably, it is 30 mol% or more, even more preferably, it is 50 mol% or more, and even more preferably, it is 70 mol% or more. In addition, when synthesizing the polymer (P), the tetracarboxylic dianhydride may be used alone or in combination of two or more.

[0042] (Diamine compounds) The specific diamine includes a compound represented by the following formula (22). [ka] (In formula (22), A 1 , A 2 , Y 1 , Y 2 and R 3 are A in the above formula (3), 1 , A 2 , Y 1 , Y 2 and R 3 is equivalent to

[0043] A in the above formula (22) 1 , A 2 , Y 1 , Y 2 and R 3 For specific and preferred examples, the explanation of the above formula (3) can be cited. Specific examples of the specific diamine include compounds represented by the following formulas (d-1) to (d-112).

[0044] [ka] [ka]

[0045] [ka] [ka]

[0046] [ka] [ka] [ka]

[0047] [ka]

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change

[0048]

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[0049]

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[0050]

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[0051] As the specific diamine, among these, the above-mentioned formula (d-1) to formula (d-3), formula (d-5), formula (d-7), formula (d-9) to formula (d-11), formula (d-13) to formula (d-15), formula (d-17), formula (d-19) to formula (d-24), formula (d-27), formula (d-29) to formula (d-38), formula (d-41), formula (d-42), formula (d-51) to formula (d-53), formula (d-55) to formula (d-60), formula (d-67), d-77), and the compounds represented by each of formulas (d-107) to (d-112) are preferred, and the compounds represented by the above formulas (d-1) to (d-3), formula (d-5), formula (d-7), formula (d-13) to (d-15), formula (d-17), formula (d-22) to (d-24), formula (d-51) to (d-53), formula (d-55), formula (d-56), and formula (d-107) to (d-112) are particularly preferred. The specific diamines can be used alone or in combination of two or more.

[0052] In synthesizing the polyamic acid (P), only the specific diamine may be used as the diamine compound, but a diamine compound different from the specific diamine (hereinafter also referred to as "other diamine") may be used together with the specific diamine.

[0053] The other diamines are not particularly limited as long as they are diamine compounds that do not have a group represented by the above formula (3), and examples thereof include aliphatic diamines, alicyclic diamines, aromatic diamines, and diaminoorganosiloxanes, etc. Specific examples of these include aliphatic diamines such as metaxylylenediamine, ethylenediamine, 1,3-propanediamine, tetramethylenediamine, and hexamethylenediamine; Alicyclic diamines such as p-cyclohexanediamine, 4,4'-methylenebis(cyclohexylamine), etc.; Examples of aromatic diamines include dodecanoxydiaminobenzene, hexadecanoxydiaminobenzene, octadecanoxydiaminobenzene, cholestanyloxydiaminobenzene, cholesteryloxydiaminobenzene, cholestanyl diaminobenzoate, cholesteryl diaminobenzoate, lanostannyl diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 2,5-diamino-N,N-diallylaniline, and compounds represented by 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-; R I is an alkanediyl group having 1 to 3 carbon atoms, and R II is a single bond or an alkanediyl group having 1 to 3 carbon atoms, a is 0 or 1, b is an integer of 0 to 2, c is an integer of 1 to 20, and d is 0 or 1. However, a and b cannot be 0 at the same time. Side chain diamines such as compounds represented by the formula: p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-ethylenedianiline, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl sulfide, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,2-bis(4-aminophenoxy)ethane, 1,5-bis(4-aminophenoxy)pentane, N,N'-di(4-aminophenyl)-N,N'-dimethylethylenediamine, bis[2-(4-aminophenyl)ethyl]hexanedioic acid, bis(4-aminophenyl)amine, N,N-bis(4-aminophenyl)methylamine, 1,4-bis non-side chain diamines such as (4-aminophenyl)-piperazine, N,N'-bis(4-aminophenyl)-benzidine, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-(phenylenediisopropylidene)bisaniline, 1,4-bis(4-aminophenoxy)benzene, 4-(4-aminophenoxycarbonyl)-1-(4-aminophenyl)piperidine, 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]dianiline; Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and the like. In addition, the diamine compounds described in JP-A-2010-97188 can be used. In addition, when synthesizing the polyamic acid (P), one type of other diamine can be used alone, or two or more types can be used in combination.

[0054] From the viewpoint of fully obtaining the effects of the present disclosure, the proportion of the specific diamine used is preferably 10 mol % or more, more preferably 20 mol % or more, even more preferably 30 mol % or more, and still more preferably 40 mol % or more, based on the total amount of the diamine compounds used in synthesizing the polyamic acid (P).

[0055] The specific diamine can be obtained by appropriately combining standard methods in organic chemistry, such as a method of synthesizing a dinitro intermediate having a nitro group instead of the primary amino group in the above formula (21), and then amminating the nitro group of the obtained dinitro intermediate using a suitable reduction system.

[0056] The method for synthesizing the dinitro intermediate can be appropriately selected depending on the target compound. For example, the structure "-YA-NO2" (A is A 1 or R 2 and Y is Y 1 Or Y 2 and an amine compound having the structure R 3 A method of reacting a dicarboxylic acid or dicarboxylic acid chloride having the structure "-YA-NO2" (A is A 1 or R 2 and Y is Y 1 Or Y 2 and a carboxylic acid having the structure R 3 with a diamine compound having the structure R 3 with a halogen compound having the structure A; a method of reacting an amine compound having the structure "-YA-NO2" with bis(4-nitrophenyl) carbonate; etc. However, the synthesis method of the specific diamine is not limited to the above.

[0057] (Synthesis of polyamic acid) The polyamic acid (P) can be obtained by reacting the above-mentioned tetracarboxylic dianhydride with a diamine compound, optionally together with a molecular weight regulator (also called an end-capping agent). Examples of the molecular weight regulator include acid monoanhydrides, monoamine compounds, and monoisocyanate compounds. The ratio of the tetracarboxylic dianhydride and the diamine compound used in the synthesis reaction of the polyamic acid (P) is preferably such that the acid anhydride group of the tetracarboxylic dianhydride is 0.2 to 2 molar equivalents per 1 molar equivalent of the amino group of the diamine compound.

[0058] The synthesis reaction of the polyamic acid (P) 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 the organic solvent used in the reaction include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Particularly preferred organic solvents are one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenols, or a mixture of one or more of these with other organic solvents (e.g., butyl cellosolve, diethylene glycol diethyl ether, etc.). 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 mass% relative to the total amount of the reaction solution. The reaction solution in which the polyamic acid (P) is dissolved may be used as it is for the preparation of a liquid crystal aligning agent, or the polyamic acid (P) contained in the reaction solution may be isolated and then used for the preparation of a liquid crystal aligning agent.

[0059] <Polyamic acid ester> The polyamic acid ester as the polymer (P) has a partial structure represented by the above formula (1), in which R 1 and R 2is a polymer having a structural unit in which at least one of the above is a monovalent organic group having 1 to 6 carbon atoms. The polyamic acid ester can be obtained, for example, by a method such as [I] reacting the polyamic acid (P) obtained above with an esterification agent (e.g., methanol, ethanol, N,N-dimethylformamide diethyl acetal, etc.), [II] reacting a tetracarboxylic acid diester with a diamine compound containing a specific diamine, preferably in an organic solvent, in the presence of a suitable dehydration catalyst (e.g., 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium halide, carbonylimidazole, a phosphorus-based condensing agent, etc.), or [III] reacting a tetracarboxylic acid diester dihalide with a diamine compound containing a specific diamine, preferably in an organic solvent, in the presence of a suitable base (e.g., tertiary amines such as pyridine and triethylamine, and alkali metals such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium, potassium, etc.).

[0060] The tetracarboxylic acid diester used in the above [II] can be obtained by ring-opening a tetracarboxylic acid dianhydride with an alcohol, etc. The tetracarboxylic acid diester dihalide used in the above [III] can be obtained by reacting the tetracarboxylic acid diester obtained as above with a suitable chlorinating agent such as thionyl chloride. The polyamic acid ester 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. When the polyamic acid ester is obtained as a solution by the above reaction, the solution may be directly used for preparing a liquid crystal aligning agent, or the polyamic acid ester contained in the reaction solution may be isolated and then used for preparing a liquid crystal aligning agent.

[0061] <Polyimide> The polyimide as the polymer (P) is a polymer having a partial structure represented by the above formula (2). The polyimide can be obtained, for example, by dehydrating and cyclizing the polyamic acid (P) synthesized as described above to convert it into an imidized product. The polyimide may be a complete imidized product in which all of the amic acid structures of the precursor polyamic acid (P) are dehydrated and cyclized, or a partial imidized product in which only a part of the amic acid structures are dehydrated and cyclized, and an amic acid structure and an imide ring structure coexist. The polyimide preferably has an imidization rate of 40 to 100%, more preferably 60 to 90%. The imidization rate is the ratio of the number of imide ring structures to the total number of amic acid structures and the number of imide ring structures of the polyimide, expressed as a percentage. Here, a part of the imide rings may be isoimide rings.

[0062] The dehydration ring-closing of the polyamic acid (P) is preferably carried out by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst to the solution, and heating as necessary. As the dehydrating agent, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride can be used. 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. As the dehydration ring-closing catalyst, for example, a tertiary amine such as pyridine, collidine, lutidine, or triethylamine can be used. The amount of the dehydration ring-closing catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. As the organic solvent used, the organic solvents exemplified as those used in the synthesis of the polyamic acid (P) can be mentioned. The reaction temperature of the dehydration ring-closing reaction is preferably 0 to 180° C., and the reaction time is preferably 1.0 to 120 hours. The reaction solution containing the polyimide thus obtained may be used as it is for the preparation of a liquid crystal aligning agent, or the polyimide may be isolated and then used for the preparation of a liquid crystal aligning agent.

[0063] The solution viscosity of the polymer (P) is preferably 10 to 800 mPa·s, and more preferably 15 to 500 mPa·s, when the polymer (P) is prepared into 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 (P) (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). The weight average molecular weight (Mw) of the polymer (P) in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably 1,000 to 500,000, more preferably 5,000 to 100,000. The molecular weight distribution (Mw / Mn) expressed as the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 15 or less, more preferably 10 or less. The polymer (P) contained in the liquid crystal aligning agent may be one type only, or two or more types may be combined.

[0064] <Other ingredients> The liquid crystal alignment agent of the present disclosure may further contain components other than the polymer (P) (hereinafter, also referred to as "other components"). Examples of other components include polymers that do not have either the partial structure represented by the above formula (1) or the partial structure represented by the above formula (2) (hereinafter, also referred to as "other polymers"), compounds having one or more epoxy groups in the molecule, functional silane compounds, compounds having one or more (meth)acryloyl groups in the molecule, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, acid generators, base generators, radical generators, etc. The blending ratio of these can be appropriately selected according to each compound within a range that does not impair the effects of the present disclosure.

[0065] <Other polymers> The main skeleton of the other polymer is not particularly limited, and examples thereof include polymers having a main skeleton of polyamic acid, polyimide, polyamic acid ester, polyorganosiloxane, polyester, cellulose derivative, polyacetal, polystyrene derivative, poly(styrene-phenylmaleimide) derivative, poly(meth)acrylate, etc. Among these, the other polymer is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

[0066] When the polymer component of the liquid crystal alignment agent of the present disclosure is composed of the polymer (P) and another polymer, it is preferable that at least one of the hydrogen-bonding groups such as amino groups and amide groups of the polymer (P) is protected by a protecting group. By introducing a protecting group into the hydrogen-bonding group, the polymer (P) becomes low polar, and when a liquid crystal alignment film is formed, the polymer (P) tends to be unevenly distributed on the air interface side, which is preferable in terms of improving the liquid crystal alignment property and voltage holding ratio.

[0067] When the other polymer is blended in the liquid crystal alignment agent, the content ratio of the other polymer is preferably 95% by mass or less, more preferably 90% by mass or less, based on the total amount of the polymer components in the liquid crystal alignment agent, from the viewpoint of fully obtaining the effect of blending the polymer (P). Note that, as the other polymer, one type may be used alone, or two or more types may be used in combination.

[0068] <Solvent> The liquid crystal aligning agent of the present disclosure is preferably prepared as a liquid composition in which the polymer (P) and other components used as necessary are dispersed or dissolved in a suitable solvent. Examples of the organic solvent to be used include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), ethylene glycol monomethyl ether, butyl lactate, butyl acetate, 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 ethers include 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, etc. These may be used alone or in combination of two or more.

[0069] The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., but is preferably in the range of 1 to 10 mass %. That is, the liquid crystal alignment agent is applied to the surface of a substrate as described below, and is preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that will become a liquid crystal alignment film. In this case, if the solid content concentration is 1 mass % or more, the thickness of the coating film can be sufficiently ensured, which is preferable in that a good liquid crystal alignment film can be easily obtained. In addition, if the solid content concentration is 10 mass % or less, the thickness of the coating film does not become too large, and a good liquid crystal alignment film can be obtained, and the viscosity of the liquid crystal alignment agent can be appropriately ensured, and the applicability can be improved.

[0070] The content of the polymer (P) in the liquid crystal alignment agent is preferably 2 parts by mass or more, and more preferably 5 parts by mass or more, per 100 parts by mass of the total of the solid components (components other than the solvent) in the liquid crystal alignment agent, from the viewpoint of fully obtaining the effect of blending the polymer (P).

[0071] <Liquid crystal alignment film and liquid crystal element> The liquid crystal alignment film of the present disclosure is formed by the liquid crystal alignment agent prepared as described above. The liquid crystal element of the present disclosure includes a liquid crystal alignment film formed by using the liquid crystal alignment agent described above. The operation mode of the liquid crystal in the liquid crystal element is not particularly limited, and can be applied to various modes such as TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, VA (Vertical Alignment) type (including VA-MVA type, VA-PVA type, etc.), IPS (In-Plane Switching) type, FFS (fringe field switching) type, OCB (Optically Compensated Bend) type, etc. The liquid crystal element can be manufactured by a method including, for example, the following steps 1 to 3. In step 1, the substrate used differs depending on the desired operation mode. Steps 2 and 3 are common to each operation mode.

[0072] (Step 1: Formation of coating film) First, a liquid crystal alignment agent is applied onto a substrate, and a coating film is formed on the substrate, preferably by heating the applied surface. As the substrate, for example, a transparent substrate made of glass such as float glass or soda glass; or plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or poly(alicyclic olefin) can be used. As the transparent conductive film provided on one side of the substrate, a NESA film (registered trademark of US PPG) made of tin oxide (SnO2), an ITO film made of indium oxide-tin oxide (In2O3-SnO2), or the like can be used. When manufacturing a TN-type, STN-type, or VA-type liquid crystal element, two substrates on which a patterned transparent conductive film is provided are used. On the other hand, when manufacturing an IPS-type or FFS-type liquid crystal element, a substrate on which an electrode made of a transparent conductive film or a metal film patterned into a comb tooth shape is provided, and an opposing substrate on which no electrode is provided are used. As the metal film, for example, a film made of a metal such as chromium can be used. The liquid crystal alignment agent is applied to the substrate on the surface on which the electrodes are formed, preferably by offset printing, spin coating, roll coating or inkjet printing.

[0073] After the liquid crystal alignment agent is applied, preheating (prebaking) is preferably performed for the purpose of preventing dripping of the applied liquid crystal alignment agent. The prebaking temperature is preferably 30 to 200°C, and the prebaking time is preferably 0.25 to 10 minutes. Thereafter, the solvent is completely removed, and a baking (postbaking) step is performed, if necessary, for the purpose of thermally imidizing the amic acid structure present in the polymer. The baking temperature (postbaking temperature) at this time is preferably 80 to 300°C, and the postbaking time is preferably 5 to 200 minutes. The film thus formed preferably has a thickness of 0.001 to 1 μm. After the liquid crystal alignment agent is applied on the substrate, the organic solvent is removed to form a liquid crystal alignment film or a coating film that will become a liquid crystal alignment film.

[0074] (Step 2: Orientation Treatment) When a TN-type, STN-type, IPS-type or FFS-type liquid crystal element is manufactured, a treatment (alignment treatment) is carried out to impart liquid crystal alignment ability to the coating film formed in the above step 1. This imparts the alignment ability of liquid crystal molecules to the coating film, forming a liquid crystal alignment film. As the alignment treatment, it is preferable to use a rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton or the like, or a photo-alignment treatment in which the coating film is irradiated with light to impart liquid crystal alignment ability. When a vertical alignment type liquid crystal element is manufactured, the coating film formed in the above step 1 may be used as it is as a liquid crystal alignment film, or the coating film may be subjected to an alignment treatment in order to further enhance the liquid crystal alignment ability.

[0075] The light irradiation in the photo-alignment treatment can be performed by a method of irradiating the coating film after the post-bake step, a method of irradiating the coating film after the pre-bake step but before the post-bake step, or a method of irradiating the coating film during heating in at least one of the pre-bake step and the post-bake step. In the photo-alignment treatment, 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. When the radiation is polarized, it may be linearly polarized or partially polarized. In addition, when the radiation used is linearly polarized or partially polarized, the radiation 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 irradiated, the direction of irradiation is an oblique direction.

[0076] 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, and excimer lasers. The radiation dose is preferably 400 to 20,000 J / m 2 and more preferably 1,000 to 5,000 J / m 2 The coating film may be irradiated with light while being heated in order to enhance the reactivity.

[0077] In producing a liquid crystal alignment film, the coating film that has been subjected to light irradiation treatment may be heated within a temperature range of 120°C to 280°C. Such a heat treatment is preferable in that it further improves the liquid crystal alignment (thermal realignment) and allows a liquid crystal element with reduced AC afterimage to be obtained. This heating may be post-baking, or may be a heat treatment carried out separately from post-baking and after post-baking. From the viewpoint of promoting realignment of molecular chains by heating, the heating temperature is preferably 140°C or higher, and more preferably 150°C to 250°C. The heating time is preferably 5 to 200 minutes, more preferably 10 to 60 minutes.

[0078] The production of the liquid crystal alignment film may further include a contacting step of contacting the coating film that has been subjected to the light irradiation treatment with water, a water-soluble organic solvent, or a mixed solvent of water and a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, 1-propanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone. Examples of the method of contacting the coating film with the solvent include, but are not limited to, spraying, showering, immersion, and puddling. The contact time between the coating film and the solvent is not particularly limited, but is, for example, 5 seconds to 15 minutes. After the contacting step, the coating film may be heat-treated.

[0079] (Step 3: Construction of liquid crystal cell) Two substrates on which a liquid crystal alignment film is formed are prepared as described above, and a liquid crystal is placed between the two substrates arranged opposite to each other to manufacture a liquid crystal cell. For example, the liquid crystal cell can be manufactured by (1) arranging two substrates opposite to each other with a gap (spacer) between them so that the liquid crystal alignment films face each other, bonding the peripheries of the two substrates together using a sealant, injecting liquid crystal into the substrate surfaces and the cell gap partitioned by the sealant, and then sealing the injection hole, or (2) applying a sealant to a predetermined location on one substrate on which a liquid crystal alignment film is formed, dropping liquid crystal into a few predetermined locations on the liquid crystal alignment film surface, bonding the other substrate so that the liquid crystal alignment film faces each other, and spreading the liquid crystal over the entire surface of the substrate (ODF method). It is desirable to further heat the manufactured liquid crystal cell to a temperature at which the liquid crystal used has an isotropic phase, and then slowly cool it to room temperature to remove the flow alignment during liquid crystal filling.

[0080] The sealing agent may be, for example, an epoxy resin containing a hardener and aluminum oxide spheres as spacers, etc. The spacers may be photospacers, bead spacers, etc.

[0081] Either positive or negative type liquid crystal may be used as the liquid crystal. When negative type liquid crystal is used in IPS type and FFS type liquid crystal elements, it is preferable because the transmission loss at the upper part of the electrode can be reduced and the contrast can be improved. In addition, the liquid crystal may be nematic liquid crystal or smectic liquid crystal, and among them, nematic liquid crystal is preferable. As the nematic liquid crystal, for example, Schiff base type liquid crystal, azoxy type liquid crystal, biphenyl type liquid crystal, phenylcyclohexane type liquid crystal, ester type liquid crystal, terphenyl type liquid crystal, biphenylcyclohexane type liquid crystal, pyrimidine type liquid crystal, dioxane type liquid crystal, bicyclooctane type liquid crystal, cubane type liquid crystal, etc. may be used. In addition, for example, cholesteric liquid crystal, chiral agent, ferroelectric liquid crystal, etc. may be added to these liquid crystals.

[0082] Next, a polarizing plate is attached to the outer surface of the liquid crystal cell as needed. Examples of polarizing plates include a polarizing film called an "H film" made by absorbing iodine while stretching and aligning polyvinyl alcohol, sandwiched between cellulose acetate protective films, or a polarizing plate made of the H film itself. This produces a liquid crystal element.

[0083] The liquid crystal element of the present disclosure can be effectively applied to various applications, and can be used in, for example, various display devices such as watches, portable game machines, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays, as well as light control films, etc. In addition, the liquid crystal element formed using the liquid crystal alignment agent of the present disclosure can also be applied to optical films such as retardation films. EXAMPLES

[0084] The present invention will be explained in more detail below with reference to examples, but it should be understood that the present invention is not limited to these examples.

[0085] The structures and abbreviations of the main compounds used in the following examples are as follows: (Tetracarboxylic acid dianhydride) TA-1; 1,2,3,4-Cyclobutanetetracarboxylic dianhydride TA-2; (1R,2R,3S,4S)-1,3-Dimethylcyclobutane-1,2,3,4-tetracarboxylic acid dianhydride TA-3; 2,3,5-Tricarboxycyclopentylacetic dianhydride TA-4; Pyromellitic dianhydride TA-5; 4,4'-Biphthalic dianhydride [ka]

[0086] (Diamine) DA-1;N 1 ,N 4-Bis(2-((5-aminopyridin-2-yl)amino)ethyl)succinamide DA-2;N 1 ,N 4 -Bis(2-((5-aminopyridin-2-yl)(tert-butoxycarbonyl)amino)ethyl)succinamide DA-3; N,N'-bis(2-((5-aminopyridin-2-yl)amino)ethyl)urea DA-4; N,N'-bis(2-((5-aminopyridin-2-yl)(tert-butoxycarbonyl)amino)ethyl)urea DA-5;N 2 ,N 6 -Bis(2-((5-aminopyridin-2-yl)amino)ethyl)pyridine-2,6-diamine DA-6;N 2 ,N 6 -Bis(2-((5-aminopyridin-2-yl)(tert-butoxycarbonyl)amino)ethyl)-N 2 ,N 6 -Di(tert-butoxycarbonyl)pyridine-2,6-diamine DA-7; N,N'-bis(5-aminopyridin-2-yl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine DA-8;N 1 ,N 6 -Bis(4-aminophenethyl)-N 1 ,N 6 -Di(tert-butoxycarbonyl)adipamide DA-9; p-phenylenediamine DA-10; 3,5-diaminobenzoic acid DA-11; 2,2'-Dimethylbenzidine DA-12; 4,4'-Diaminodiphenylmethane DA-13;N 4 ,N 4 '-Bis(4-aminophenyl)-N 4 ,N 4 '-Dimethylbenzidine DA-14;N 1 ,N 4-Bis(5-aminopyridin-2-yl)succinamide DA-15;N 1 ,N 4 -Bis(5-aminopyridin-2-yl)-N 1 ,N 4 -Dimethylsuccinamide

[0087] [ka] [ka] [ka]

[0088] (End-capping agent) EC-1; N-(tert-butoxycarbonyl)-ethylenediamine EC-2; Maleic anhydride EC-3; 4-Aminobenzoic acid [ka]

[0089] (Additives) AD-1; N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane AD-2;3-Glycidyloxypropyltriethoxysilane AD-3; Dipentaerythritol hexaacrylate [ka]

[0090] (solvent) NMP; N-methyl-2-pyrrolidone BC: Butyl cellosolve THF; Tetrahydrofuran EDC; 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride

[0091] <Synthesis of Compounds> [Synthesis Example 1] Ethylenediamine (100 mL) and sodium carbonate (120 mmol) were placed in a three-neck flask equipped with a nitrogen inlet tube. A THF solution of 2-chloro-5-nitropyridine (120 mmol) was added dropwise under nitrogen and stirred at 50°C for 6 hours. After the reaction was completed, the mixture was concentrated under reduced pressure, and NMP was added to the concentrated residue to dissolve it. The resulting solution was filtered to remove insoluble salts, thereby obtaining an NMP solution of N-(5-nitropyridin-2-yl)ethylenediamine. [ka]

[0092] Succinic acid (10 mmol), EDC (22 mmol), and NMP (20 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred for 30 minutes. An NMP solution of N-(5-nitropyridin-2-yl)ethylenediamine (22 mmol) was then added and stirred at room temperature for 4 hours. After the reaction was completed, the reaction solution was poured into water to precipitate the product. The precipitate was filtered and washed with water to obtain the dinitro form (N 1 ,N 4 -Bis(2-((5-nitropyridin-2-yl)amino)ethyl)succinamide) was obtained (yield 83%). The dinitro compound (5.0 mmol), di-tert-butyl dicarbonate (11 mmol), and NMP (10 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred at room temperature for 8 hours. After the reaction was completed, ethyl acetate was added and the mixture was separated and washed with water. The organic phase was concentrated under reduced pressure to obtain the Boc-protected dinitro compound (N 1 ,N 4 -bis(2-((5-nitropyridin-2-yl)(tert-butoxycarbonyl)amino)ethyl)succinamide) was obtained (yield 57%). The above Boc-protected dinitro derivative (2.0 mmol), Pd / C (0.1 g), hydrazine monohydrate (20 mmol), and ethanol (10 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred at room temperature for 4 hours. After the reaction was completed, the reaction solution was filtered through Celite, ethyl acetate was added, and the mixture was separated and washed with water. The organic phase was concentrated under reduced pressure to obtain the diamine represented by the above formula (DA-2) (yield 28%). [ka]

[0093] [Synthesis Example 2] The diamine represented by the above formula (DA-1) was synthesized according to the following synthesis scheme. [ka]

[0094] [Synthesis Example 3] A solution of N-(5-nitropyridin-2-yl)ethylenediamine (30 mmol) in NMP and bis(4-nitrophenyl)carbonate (10 mmol) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred at room temperature for 4 hours. After the reaction was completed, the reaction solution was left to stand overnight to precipitate the product. The precipitate was filtered and washed with water to obtain the dinitro form (N,N'-bis(2-((5-nitropyridin-2-yl)amino)ethyl)urea) (yield 78%). The dinitro compound (4.4 mmol), di-tert-butyl dicarbonate (9.7 mmol), DMAP (0.44 mmol), and NMP (10 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred at room temperature for 6 hours. After the reaction was completed, ethyl acetate was added and the mixture was separated and washed with water. The organic phase was concentrated under reduced pressure to obtain the Boc-protected dinitro compound (N,N'-bis(2-((5-nitropyridin-2-yl)(tert-butoxycarbonyl)amino)ethyl)urea) (yield 86%). The above Boc-protected dinitro derivative (2.0 mmol), Pd / C (0.1 g), hydrazine monohydrate (20 mmol), and ethanol (10 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred at room temperature for 4 hours. After the reaction was completed, the reaction solution was filtered through Celite, ethyl acetate was added, and the mixture was separated and washed with water. The organic phase was concentrated under reduced pressure to obtain the diamine represented by the above formula (DA-4) (yield 23%). [ka]

[0095] [Synthesis Example 4] The diamine represented by the above formula (DA-3) was synthesized according to the following synthesis scheme. [ka]

[0096] [Synthesis Example 5] The diamine represented by the above formula (DA-6) was synthesized according to the following synthesis scheme. [ka]

[0097] [Synthesis Example 6] The diamine represented by the above formula (DA-5) was synthesized according to the following synthesis scheme. [ka]

[0098] [Synthesis Example 7] The diamine represented by the above formula (DA-14) was synthesized according to the following synthesis scheme. [ka]

[0099] [Synthesis Example 8] The diamine represented by the above formula (DA-15) was synthesized according to the following synthesis scheme. [ka]

[0100] <Polymer synthesis> [Synthesis Example 9] Diamines (50 mol parts (DA-1) and 50 mol parts (DA-11)) and end-capping agent (10 mol parts (EC-1)) were dissolved in NMP, and 0.95 mol equivalents of tetracarboxylic dianhydride (100 mol parts (TA-2) per 100 mol parts of the total amount of tetracarboxylic dianhydride used in the synthesis) were added to the total amount of diamines, and the reaction was carried out at room temperature for 6 hours to obtain a polyamic acid solution. 0.75 mol equivalents of 1-methylpiperidine and acetic anhydride were added to the obtained solution as dehydrating agents relative to the carboxyl groups of the polyamic acid, and the mixture was heated and stirred at 60°C for 3 hours. The obtained solution was repeatedly concentrated under reduced pressure and diluted with NMP to obtain a 10 mass% solution of polyimide (PI-1) having a partial structure represented by the following formula (PI-1). The polyimide (PI-1) 1 H-NMR spectrum (DMSO-d 6 The imidization rate was calculated from the integral ratio of aromatic protons (δ 6.4 to 9.0 ppm) and main chain amide protons (δ 9.8 to 10.3 ppm), and was found to be 76%. [ka]

[0101] [Synthesis Examples 10-16] Polyimides (PI-2 to PI-8) were obtained in the same manner as in Synthesis Example 9, except that the types and molar ratios of tetracarboxylic dianhydrides and diamines were changed as shown in Table 1 below. The values ​​in Table 1 indicate the ratio (mol%) of each compound used relative to the total amount (100 mol%) of tetracarboxylic dianhydrides used in the synthesis, and the values ​​in Table 1 indicate the ratio (mol%) of each compound used relative to the total amount (100 mol%) of diamines used in the synthesis. The values ​​of the dehydrating agent indicate the ratio (mol%) of each compound used relative to the amount of carboxyl groups in polyamic acid (100 mol%).

[0102] [Synthesis Example 17] Diamines (50 mol parts of (DA-4) and 50 mol parts of (DA-9)) were dissolved in NMP, and 0.95 mol equivalents of tetracarboxylic dianhydride (75 mol parts of (TA-2) and 25 mol parts of (TA-1) per 100 mol parts of the total amount of tetracarboxylic dianhydride used in the synthesis) were added relative to the total amount of diamines, and the reaction was carried out at room temperature for 6 hours to obtain a solution of polyamic acid. 0.50 mol equivalents of 1-methylpiperidine and acetic anhydride relative to the carboxyl group of polyamic acid were added to the obtained solution, and the mixture was heated and stirred at 60°C for 3 hours. The obtained solution was repeatedly concentrated under reduced pressure and diluted with NMP to obtain a 10 mass% solution of polyimide (PI-9) having a partial structure represented by the following formula (PI-9). The polyimide (PI-9) 1 H-NMR spectrum (DMSO-d 6 The imidization rate was calculated from the integral ratios of the aromatic protons (δ 6.4 to 9.0 ppm), main chain amide protons (δ 9.8 to 10.3 ppm), and acetyl terminal amide protons (δ 9.6 to 9.8 ppm), and was found to be 52%. [ka]

[0103] [Synthesis Example 18] A polyimide (PI-10) was obtained in the same manner as in Synthesis Example 17, except that the types and molar ratios of the tetracarboxylic dianhydride and diamine were changed as shown in Table 1 below.

[0104] [Synthesis Example 19] Diamines (50 molar parts of (DA-2) and 50 molar parts of (DA-11)) were dissolved in NMP, and 0.95 molar equivalents of tetracarboxylic dianhydride (100 molar parts of (TA-2) per 100 molar parts of the total amount of tetracarboxylic dianhydride used in the synthesis) was added relative to the total amount of diamines. The reaction was carried out at room temperature for 6 hours to obtain a 15% by mass solution of polyamic acid (PI-11) having a partial structure represented by the following formula (PI-11). [ka]

[0105] [Synthesis Example 20] In a three-neck flask equipped with a nitrogen inlet tube, tetracarboxylic dianhydride (TA-2) (40 mmol) and NMP (40 mL) were added and stirred at 100 ° C for 30 minutes, and then a solution of diamine (DA-11) (20 mmol) in NMP was added dropwise, followed by stirring at 100 ° C for 1 hour. Furthermore, acetic anhydride (60 mmol) and N-methylpiperidine (10 mmol) were added and stirred at 100 ° C for 1 hour. After the reaction was completed, the reaction solution was filtered and poured into water to precipitate the product. The precipitate was filtered, stirred and washed in boiling water, and vacuum dried at 60 ° C. The obtained solid was anhydrified in excess acetic anhydride / acetic acid to obtain an intermediate (PI-12-1) represented by the following formula (PI-12-1). Next, the intermediate (PI-12-1) was dissolved in NMP, and 1.0 molar equivalent of diamine (50 molar parts of (DA-2) per 100 molar parts of the total amount of diamines used in the synthesis) was added to the intermediate, and the reaction was carried out at room temperature for 6 hours to obtain a 10 mass% solution of polyimide (PI-12) having a partial structure represented by the following formula (PI-12). [ka]

[0106] [Synthesis Example 21] Diamines (75 mol parts of (DA-2) and 25 mol parts of (DA-11)) were dissolved in NMP, and 0.95 molar equivalents of tetracarboxylic dianhydride (75 mol parts of (TA-1) and 25 mol parts of (TA-3) per 100 mol parts of the total amount of tetracarboxylic dianhydride used in the synthesis) were added to the total amount of diamines, and the reaction was carried out at room temperature for 6 hours. Furthermore, a terminal blocking agent (10 mol parts of (EC-2)) was added and the reaction was carried out at room temperature for 3 hours, to obtain a 15 mass% solution of polyamic acid (PI-13) having a partial structure represented by the following formula (PI-13). [ka]

[0107] [Synthesis Examples 22-25] Polyamic acids (PI-14 to PI-17) were obtained in the same manner as in Synthesis Example 21 except that the types and molar ratios of the tetracarboxylic dianhydrides and diamines were changed as shown in Table 1 below. [Synthesis Example 26] A polyimide (PI-18) was obtained in the same manner as in Synthesis Example 17, except that the types and molar ratios of the tetracarboxylic dianhydride and diamine were changed as shown in Table 1 below.

[0108] [Synthesis Example 27] Diamines (50 molar parts of (DA-2) and 50 molar parts of (DA-8)) were dissolved in NMP, and 0.95 molar equivalents of tetracarboxylic dianhydride (50 molar parts of (TA-4) and 50 molar parts of (TA-3) per 100 molar parts of the total amount of tetracarboxylic dianhydride used in the synthesis) were added relative to the total amount of diamines, and the reaction was carried out at room temperature for 6 hours to obtain a 15% by mass solution of polyamic acid (PI-19).

[0109] [Synthesis Examples 28-30] Polyamic acids (PI-20 to PI-22) were obtained in the same manner as in Synthesis Example 27 except that the types and molar ratios of the tetracarboxylic dianhydrides and diamines were changed as shown in Table 1 below.

[0110] [Synthesis Example 31] Diamines (75 molar parts of (DA-10) and 25 molar parts of (DA-12)) and an end-capping agent (10 molar parts of (EC-3)) were dissolved in NMP, and 0.95 molar equivalents of tetracarboxylic dianhydride (75 molar parts of (TA-3) and 25 molar parts of (TA-1) per 100 molar parts of the total amount of tetracarboxylic dianhydride used in the synthesis) were added relative to the total amount of diamines. The reaction was carried out at room temperature for 6 hours to obtain a 15% by mass solution of polyamic acid (PI-23).

[0111] [Synthesis Examples 32 to 34] Polyamic acids (PI-24 to PI-26) were obtained in the same manner as in Synthesis Example 31 except that the types and molar ratios of the tetracarboxylic dianhydrides and diamines were changed as shown in Table 1 below.

[0112] [Synthesis Examples 35 and 36] Polyimides (PI-27 and PI-28) were obtained in the same manner as in Synthesis Example 17, except that the types and molar ratios of the tetracarboxylic dianhydride and diamine, and the molar ratio of the dehydrating agent were changed as shown in Table 1 below.

[0113] [Table 1]

[0114] <Preparation and Evaluation of Liquid Crystal Alignment Agent> [Example 1: Photo-aligned FFS-type liquid crystal display element] (1) Preparation of liquid crystal alignment agent The polymer (solid content: (PI-1) 100 parts by mass) was diluted with NMP and butyl cellosolve (BC) to obtain a solution with a solid content concentration of 4.0% by mass and a solvent composition ratio of NMP:BC = 70:30 (mass ratio). The solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (R-1).

[0115] (2) Evaluation of solubility In the above (1), the solubility of the polymer was also evaluated. When the polymer could be diluted and a sufficient amount of filtrate could be recovered when the solution was filtered through a filter, the evaluation was "good." When the polymer was diluted and suspension or aggregation occurred and a sufficient amount of filtrate could not be recovered when the solution was filtered through a filter, the evaluation was "poor." As a result, this example was evaluated as "good."

[0116] (3) Formation of liquid crystal alignment film by photoalignment method The liquid crystal alignment agent (R-1) prepared in (1) above was applied to each surface of a glass substrate having a flat electrode, an insulating layer, and a comb-shaped electrode laminated in this order on one side, and an opposing glass substrate having no electrode, using a spinner, and then dried on a hot plate at 80°C for 1 minute, and then dried in an oven at 230°C with the interior replaced with nitrogen for 30 minutes to form a coating film with an average thickness of 0.1 μm. The surface of this coating film was irradiated with 300 mJ / cm2 of linearly polarized ultraviolet light containing a 254 nm emission line using an Hg-Xe lamp. 2 The coating film subjected to the above-mentioned photo-alignment treatment was subjected to heat treatment in an oven at 230° C. with the inside of the oven replaced with nitrogen for 30 minutes to form a liquid crystal alignment film.

[0117] (4) Manufacture of liquid crystal display elements For the pair of substrates having the liquid crystal alignment film prepared in (3) above, an epoxy resin adhesive containing aluminum oxide spheres with a diameter of 3.5 μm was dispensed with a dispenser, leaving a liquid crystal injection port on the edge of the surface on which the liquid crystal alignment film was formed, and the substrates were then stacked and pressed together, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative nematic liquid crystal (Merck, MJ20195NCMP) was filled between the pair of substrates through the liquid crystal injection port, and the liquid crystal injection port was sealed with an epoxy adhesive. Furthermore, in order to remove the flow alignment that occurred during liquid crystal injection, the substrates were heated at 120°C and then slowly cooled to room temperature.

[0118] (5) Evaluation of liquid crystal alignment (AC image retention characteristics) The liquid crystal display element manufactured in (4) above was measured for change in liquid crystal azimuth angle before and after driving it for 7 days at an AC voltage of 12V using a birefringence meter (AXOSTEP high-precision Mueller matrix imaging polarimeter, manufactured by AXOMETRICS). A change in liquid crystal azimuth angle of less than 1 degree was rated as "good", and a change of 1 degree or more was rated as "poor". The smaller the change in liquid crystal azimuth angle, the less likely AC afterimages are to occur even when the liquid crystal display element is driven for a long period of time, and the better the liquid crystal alignment is. As a result, this example was rated as "good". (6) Evaluation of voltage retention rate (long-term reliability) An ECB type liquid crystal display element was manufactured in the same manner as in (3) and (4) above, except that the glass substrate was changed to ECB (Electrically Controlled Birefringence). After leaving this liquid crystal display element on a backlight for 7 days, the voltage retention rate was measured using a voltage retention rate measuring device (VHR-1, manufactured by Toyo Corporation) while it was heated in an oven at 70°C. A voltage of 1V was applied for 60 microseconds at a 1-second cycle, and a voltage retention rate of 90% or more 1 second after the application was removed was rated as "good", and a voltage retention rate of less than 90% was rated as "bad". The higher the measured voltage retention rate, the higher the reliability of the liquid crystal display element. As a result, in this example, it was rated as "good".

[0119] [Examples 2 to 13, Comparative Examples 1 to 3] In the above Example 1, except that the polymer and additives contained in the liquid crystal alignment agent were changed as shown in Table 2 below, the liquid crystal alignment agent was prepared and a liquid crystal alignment film was formed by a photoalignment method in the same manner as in Example 1, and a liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 2 below.

[0120] [Table 2]

[0121] As shown in Table 2, the liquid crystal alignment agents of Examples 1 to 13 containing the polymer (P) had good polymer solubility, and when a liquid crystal alignment film was formed by a photoalignment method to manufacture an FFS-type liquid crystal display element, both the liquid crystal alignment property (AC afterimage characteristics) and the voltage holding ratio (long-term reliability) were "good." In contrast, the liquid crystal alignment agents of Comparative Examples 1 to 3 not containing the polymer (P) were inferior to the Examples in at least one of the polymer solubility, liquid crystal alignment property, and voltage holding ratio.

[0122] Considering the results of Examples 1 to 13 and Comparative Examples 1 to 3, the solubility of the polymer was "good" in all of Examples 1 to 13, and "poor" in Comparative Example 1. A polymer having a hydrogen-bonding group that strongly interacts with another molecule has a problem of low solubility in a solvent. However, the polymer (P) has a specific spacer structure (-Y 1 -R 3 -Y 2 It is presumed that the polymer had good solubility because it had a nitrogen-containing aromatic ring bonded to this spacer structure.

[0123] Specifically, in the case of a polymer having a thermally detachable group (bulky substituents can improve the solubility of the polymer, but since their presence on the film surface disrupts the liquid crystal alignment, it is desirable for the group to be thermally detached), the polymer had good solubility even when it had a hydrogen-bonding group. For example, in Example 3, the polymer (P) has a urea bond and two Boc groups as protecting groups, and it is presumed that the solubility of the polymer was improved. It should be noted that another possible factor for the improved solubility is that the basicity of the polymer is reduced by protecting the amino groups, suppressing the interaction with the remaining polyamic acid moieties. On the other hand, in Comparative Example 1, the polymer had a urea bond but no thermally detachable group, and it is presumed that this was because the solubility of the polymer (particularly, the solubility in BC, which is a poor solvent) was poor.

[0124] With regard to the liquid crystal alignment property, all of Examples 1 to 13 were "good", while Comparative Example 3 was "poor". This is because, in Examples 1 to 13, Y 1 , Y2 Since the aromatic ring to which is bonded is connected to the imide group, it is presumed that the photodecomposition due to the retro [2+2] reaction of the cyclobutane ring is promoted by the photoinduced electron transfer (electron transfer sensitization reaction) from the diamine partial structure to the cyclobutane ring. Furthermore, in Examples 1 to 13, the polymer (P) has a divalent saturated aliphatic hydrocarbon group, and the flexibility of the molecular chain is high, and it is presumed that the self-organized orientation of the molecular chain due to molecular motion is induced in the heat treatment process after exposure, and the anisotropy is increased. As a result, it is presumed that in Examples 1 to 13, the anisotropy of the molecular orientation is efficiently expressed with a small amount of exposure, and the liquid crystal alignment is good. On the other hand, it is presumed that the photodecomposition reaction did not occur sufficiently in Comparative Example 3, and therefore the liquid crystal alignment is poor.

[0125] With regard to the voltage holding ratio, all of Examples 1 to 13 were "good", while Comparative Examples 2 and 3 were "poor". In Examples 1 to 13, since the polymer (P) has a hydrogen-bonding group (amide bond, urea bond, or 2,6-diaminopyridine skeleton), multipoint hydrogen bonds are formed between molecules, suppressing molecular mobility in the operating temperature range of the liquid crystal display element, suppressing the dielectric polarization of the liquid crystal alignment film, and suppressing the movement and diffusion of impurities captured in the liquid crystal alignment film, which is presumably why the voltage holding ratio is improved. Furthermore, since the polymer (P) has a basic group (2-aminopyridine skeleton), it is presumed that it can efficiently capture acidic components (formic acid, etc.) among impurities present in the liquid crystal (impurities and heat / photolysis products derived from negative nematic liquid crystals, elution from liquid crystal sealant into the liquid crystal, etc.), thereby improving the voltage holding ratio. Furthermore, since the polymer (P) has a basic group, physical crosslinks can be formed through intermolecular interactions between the polymer (P) and acidic groups (such as carboxyl groups) contained in other polymers, additives, etc., and it is presumed that this further improves the voltage retention rate.

[0126] Furthermore, if the voltage retention rate is good even after long-term operation, various display defects resulting from impurities in the liquid crystal that occur when a liquid crystal display element is used for a long period of time (for example, line image retention; a linear image retention phenomenon that occurs at the pattern boundary when the entire surface is switched to a grayscale display after displaying a black and white checkered pattern) can be suppressed, and a liquid crystal display element with excellent long-term reliability tends to be obtained.

[0127] The polymers (P) of Examples 12 and 13 have the same monomer composition but different polymerization sequences. The polymer (P) of Example 12 is a random copolymer (PI-11) with an uncontrolled polymerization sequence, whereas the polymer (P) of Example 13 is an alternating copolymer (PI-12) with a controlled polymerization sequence, and has a structure in which repeating units derived from diamines (DA-2) and (DA-11) are alternately linked. With regard to the liquid crystal alignment, both Examples 12 and 13 were "good", but the change in the liquid crystal azimuth angle of Example 13 was smaller than that of Example 12, and it was found that the liquid crystal alignment was better.

[0128] This is presumably because in the alternating copolymer (PI-12), both a diamine having a spacer structure (such as an alkylene group) and a diamine having a mesogen structure (a structure containing a relatively large number of aromatic rings) are bonded to one cyclobutane ring site, and the photoreactivity and molecular mobility of the polymer are uniform within the molecule. Therefore, it is presumed that the structural change caused by the photoreaction can more directly promote the change in molecular orientation of the mesogen site. On the other hand, in the random copolymer (PI-11), a partial structure is included in which only two of either a diamine having a spacer structure and a diamine having a mesogen structure are bonded to one cyclobutane ring site, and the photoreactivity and molecular mobility of the polymer are nonuniform within the molecule. Therefore, it is presumed that, particularly when the baking temperature is high, the molecular mobility is locally increased, and the anisotropy of the molecular orientation associated with the structural change caused by the photoreaction is easily alleviated. Note that although the polymer (P) in Comparative Example 2 is a random copolymer, it has been found that when it is an alternating copolymer with a controlled polymerization sequence, the liquid crystal alignment is similarly improved.

[0129] [Example 14] Since the polymer (P) has a hydrogen-bonding group and a basic group, it is likely to be highly polar, and therefore, when it is mixed with another polymer with low polarity and low surface free energy to form a coating film, it is likely to be unevenly distributed on the substrate interface side rather than the air interface side. Therefore, in order to verify the effect of the polymer blend of the polymer (P) and another polymer, a liquid crystal alignment agent was prepared in the same manner as in Example 1, except that the blending formulation was changed to that shown in Table 3 below, and a liquid crystal alignment film was formed by a photoalignment method, and a liquid crystal display element was manufactured and various evaluations were performed, and the results were compared with those of Examples 1 to 13 above.

[0130] [Table 3]

[0131] As a result, the liquid crystal alignment property and the voltage holding ratio were lower in Example 14 than in Example 1 in which no other polymer was blended. This result is presumably due to the fact that the polymer (PI-1) tends to be unevenly distributed on the substrate interface side.

[0132] On the other hand, when the polymer (P) had a thermally detachable group as a protecting group for a polar functional group such as an amino group, the liquid crystal alignment and voltage holding ratio were better than those of Example 14 even when other polymers were blended (Examples 2, 3, and 5 to 13). This is presumably because when the polymer (P) had a thermally detachable group as a protecting group for a polar functional group such as an amino group, the polymer (P) had relatively low polarity, and even when a coating film was formed as a polymer blend with other polymers, the polymer (P) was likely to be unevenly distributed on the air interface side, and as a result, good liquid crystal alignment and voltage holding ratio were achieved.

[0133] [Example 15: Rubbing alignment FFS type liquid crystal display element] (1) Preparation of liquid crystal alignment agent The polymer (solid content: (PI-11) 10 parts by mass, (PI-19) 45 parts by mass, (PI-21) 45 parts by mass) and additive ((AD-1) 5 parts by mass) were diluted with NMP and BC to obtain a solution with a solid content concentration of 4.0% by mass and a solvent composition ratio of NMP:BC = 70:30 (mass ratio). The liquid crystal alignment agent (R-15) was prepared by filtering this solution through a filter with a pore size of 0.2 μm.

[0134] (2) Evaluation of solubility In the above (1), the solubility of the polymer was also evaluated. If the polymer could be diluted and the solution could be filtered through a filter, it was rated as "good", and if suspension or aggregation occurred when the polymer was diluted and the solution could not be filtered through a filter, it was rated as "poor". As a result, this example was rated as "good".

[0135] (3) Formation of liquid crystal alignment film by rubbing method The liquid crystal alignment agent (R-15) prepared in (1) above was applied to each surface of a glass substrate having a flat electrode, an insulating layer, and a comb-shaped electrode laminated in this order on one side, and a counter glass substrate having no electrode, using a spinner, and then dried on a hot plate at 80°C for 1 minute, and then dried in an oven at 230°C with the inside of the oven replaced with nitrogen for 30 minutes to form a coating film with an average thickness of 0.1 μm. The surface of this coating film was rubbed twice using a rubbing machine having a roll wrapped with nylon cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 30 mm / sec, and a pile indentation length of 0.3 mm. The coating film subjected to the rubbing alignment treatment was ultrasonically cleaned in ultrapure water for 1 minute, and then dried in an oven at 100°C for 10 minutes to form a liquid crystal alignment film.

[0136] (4) Manufacture of liquid crystal display elements An FFS-mode liquid crystal display element was produced in the same manner as in Example 1 using a pair of substrates having the liquid crystal alignment film prepared in (3) above. (5) Evaluation of liquid crystal alignment (AC image retention characteristics) The liquid crystal display element manufactured in (4) above was evaluated for liquid crystal alignment properties (AC afterimage characteristics) in the same manner as in Example 1. As a result, this example was rated as "good." (6) Evaluation of voltage retention rate (long-term reliability) An ECB type liquid crystal display element was manufactured in the same manner as in (3) and (4) above, except that the glass substrate was changed to ECB. The voltage holding ratio (long-term reliability) of this liquid crystal display element was evaluated in the same manner as in Example 1. As a result, this example was evaluated as "good."

[0137] [Examples 16 to 21, Comparative Examples 4 to 5] In the above Example 15, except that the polymer and additives contained in the liquid crystal alignment agent were changed as shown in Table 4 below, the liquid crystal alignment agent was prepared and a liquid crystal alignment film was formed by a rubbing method in the same manner as in Example 15, and a liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 4 below.

[0138] [Table 4]

[0139] As shown in Table 4, the liquid crystal alignment agents of Examples 15 to 21 containing the polymer (P) had good polymer solubility. In addition, when a liquid crystal alignment film was formed by a rubbing method to manufacture an FFS-type liquid crystal display element, both the liquid crystal alignment property (AC afterimage characteristics) and the voltage holding ratio (long-term reliability) were "good." In contrast, the liquid crystal alignment agents of Comparative Examples 4 and 5 not containing the polymer (P) had voltage holding ratios inferior to those of the Examples.

[0140] Considering the results of Examples 15 to 21 and Comparative Examples 4 and 5, the polymer solubility was "good" in all of Examples 15 to 21. This is because the polymers (P) in Examples 15 to 21 had specific spacer structures, and as described above, the solubility of the polymers was good in all of the cases, despite having hydrogen-bonding groups.

[0141] The liquid crystal alignment was evaluated as "good" in all of Examples 15 to 21. This is presumably because the polymers (P) in Examples 15 to 21 have a divalent saturated aliphatic hydrocarbon group, and the molecular chains are highly flexible, so that the film is easily stretched when a shear stress is applied to the film by a rubbing method, and thus the orientation of the molecular chains is efficiently induced.

[0142] Concerning the voltage holding ratio (long-term reliability), all of Examples 15 to 21 were "good", while Comparative Examples 4 and 5 were "poor". The polymers (P) in Examples 15 to 21 have hydrogen-bonding groups and basic groups, and it is presumed that the voltage holding ratio was good as described above. On the other hand, the polymers used in Comparative Examples 4 and 5 do not have either or both of the hydrogen-bonding groups and basic groups, and therefore it is presumed that the voltage holding ratio was poor. Note that this discussion is merely speculation and does not limit the contents of the present disclosure in any way.

[0143] [Examples 22 and 23] In the above Example 1, the polymer contained in the liquid crystal alignment agent was changed as shown in Table 5 below, and the amount of ultraviolet light irradiation in the photoalignment treatment was 500 mJ / cm2 A liquid crystal alignment agent was prepared and a liquid crystal alignment film was formed by a photoalignment method in the same manner as in Example 1, except for changing the above. A liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 5 below.

[0144] [Table 5]

[0145] As shown in Table 5, the liquid crystal alignment agents of Examples 22 and 23 containing the polymer (P) had good polymer solubility. In addition, the liquid crystal display element obtained had both "good" liquid crystal alignment properties (AC afterimage characteristics) and voltage retention rate (long-term reliability).

[0146] From the above, it was found that the liquid crystal aligning agent of the present disclosure containing the polymer (P) can provide a liquid crystal element with excellent liquid crystal alignment properties and voltage holding ratio.

Claims

1. A liquid crystal aligning agent comprising a polymer (P) having at least one selected from the group consisting of a partial structure represented by the following formula (1) and a partial structure represented by the following formula (2): 【Chemistry 1】 (In formula (1) and formula (2), X １ is a tetravalent organic group. ２ R is a divalent organic group represented by the following formula (3). １ and R ２ are each independently a hydrogen atom or a monovalent organic group having 1 to 6 carbon atoms. 【Chemistry 2】 (In formula (3), A １ and A ２ are each independently a divalent aromatic group. １ and A ２ At least one of the groups is a divalent heterocyclic aromatic group having a nitrogen atom. Y １ and Y ２ each independently represents a single bond, "-O-", "-S-", or "-NR ４ -”, “-COO-”, “-NR ４ -CO-" or a divalent group having a nitrogen-containing non-aromatic heterocycle. R ３ At least one arbitrary methylene group in the divalent saturated aliphatic hydrocarbon group having 2 to 20 carbon atoms is “—O—”, “—S—”, or any one of the following formulas (4) to (10): 【Chemistry 3】 is a divalent organic group substituted with at least one of the groups represented by the formula: ３ R contains at least one group selected from the groups represented by the above formulas (4) to (10). ３ In the formula (4), "-O-", "-S-", and the groups represented by the formulae (4) to (10) are not adjacent to each other, and the two bonds of "-O-", "-S-", and the groups represented by the formulae (4) to (10) are each bonded to a carbon atom constituting a hydrocarbon group, a nitrogen-containing non-aromatic heterocycle, or a nitrogen-containing aromatic heterocycle. R ４ and R ５ are each independently a hydrogen atom or a monovalent organic group, or R ４ and R ５ and are combined together to form R ４ The nitrogen atom to which R is bonded and ５ represents a ring structure formed together with the nitrogen atom to which R is bonded. ６ , R ７ and R ８ are each independently a hydrogen atom or a monovalent organic group. However, R ３ When Y contains any one of the divalent groups represented by the above formulas (5) to (7), １ , Y ２ and R ３ At least one of them has a protecting group for the polar functional group. A ３ is a divalent heterocyclic aromatic group having a nitrogen atom. "*" indicates a bond.

2. The X ２ The liquid crystal aligning agent according to claim 1 , wherein the polar functional group is a protecting group.

3. The X ２ The liquid crystal aligning agent according to claim 1 or 2, wherein the protecting group of the polar functional group is two or more.

4. The X ２ The liquid crystal aligning agent according to any one of claims 1 to 3, wherein a protecting group for the polar functional group of is a tert-butoxycarbonyl group.

5. The X ２ is a group represented by the following formula (11), a group represented by the following formula (12), or a group represented by the following formula (13): The liquid crystal aligning agent according to any one of claims 1 to 4. 【Chemistry 4】 (In formulas (11) to (13), Y ３ and Y ４ are each independently "* １ -NR ９ -CO-" or "-NR ９ -CO-* １ " " １ " is "-(CH ２ ) ｒ -" indicates a bond. ９ , R １０ , R １１ , R １３ and R １４ are each independently a hydrogen atom or a monovalent organic group. １ , Y ２ , R １０ and R １１ At least one of the above has a protecting group for a polar functional group. r is an integer of 1 to 6. s and t are each independently an integer of 0 to 6, provided that 1≦r+s+t≦12 is satisfied. v, w, e and f are each independently an integer of 1 to 6. u is an integer of 0 to 2. A １ , A ２ , Y １ , and Y ２ is defined as the above formula (3). "*" indicates a bond.)

6. The X １ The liquid crystal aligning agent according to any one of claims 1 to 5, wherein is a tetravalent group represented by any one of the following formulas (14) to (21): 【Chemistry 5】 (In formulas (14) to (21), "*" indicates a bond.)

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

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

9. A polymer having at least one member selected from the group consisting of a partial structure represented by the following formula (1) and a partial structure represented by the following formula (2): 【Chemistry 6】 (In formula (1) and formula (2), X １ is a tetravalent organic group. ２ R is a divalent organic group represented by the following formula (3). １ and R ２ are each independently a hydrogen atom or a monovalent organic group having 1 to 6 carbon atoms. 【Chemistry 7】 (In formula (3), A １ and A ２ are each independently a divalent aromatic group. １ and A ２ At least one of the groups is a divalent heterocyclic aromatic group having a nitrogen atom. Y １ and Y ２ each independently represents a single bond, "-O-", "-S-", or "-NR ４ -”, “-COO-”, “-NR ４ -CO-" or a divalent group having a nitrogen-containing non-aromatic heterocycle. R ３ At least one arbitrary methylene group in the divalent saturated aliphatic hydrocarbon group having 2 to 20 carbon atoms is “—O—”, “—S—”, or any one of the following formulas (4) to (10): 【Chemistry 8】 is a divalent organic group substituted with at least one of the groups represented by the formula: ３ R contains at least one group selected from the groups represented by the above formulas (4) to (10). ３ In the formula (4), "-O-", "-S-", and the groups represented by the formulae (4) to (10) are not adjacent to each other, and the two bonds of "-O-", "-S-", and the groups represented by the formulae (4) to (10) are each bonded to a carbon atom constituting a hydrocarbon group, a nitrogen-containing non-aromatic heterocycle, or a nitrogen-containing aromatic heterocycle. R ４ and R ５ are each independently a hydrogen atom or a monovalent organic group, or R ４ and R ５ and are combined together to form R ４ The nitrogen atom to which R is bonded and ５ represents a ring structure formed together with the nitrogen atom to which R is bonded. ６ , R ７ and R ８ are each independently a hydrogen atom or a monovalent organic group. However, R ３ When Y contains any one of the divalent groups represented by the above formulas (5) to (7), １ , Y ２ and R ３ At least one of them has a protecting group for the polar functional group. A ３ is a divalent heterocyclic aromatic group having a nitrogen atom. "*" indicates a bond.

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