Liquid crystal alignment agent, liquid crystal alignment film, liquid crystal element and method for producing the same

Abstract

This invention provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal element, as well as a method for manufacturing the same, which can obtain a liquid crystal element with a stable pretilt angle and excellent long-term heat resistance even when the thickness of the liquid crystal alignment film is thinned due to poor coating, etc. In this invention, the liquid crystal alignment agent contains a polymer [P]. The polymer [P] is a partial structure in which the side chains of the polymer have at least one of the functions of free radical generation (e.g., generating free radicals upon light irradiation) and photosensitizing (e.g., exhibiting a sensitizing effect upon light irradiation), and has at least one of the structural units represented by formulas (1) to (4). X1 to X4 are partial structures having at least one of the functions of free radical generation (e.g., generating free radicals upon light irradiation) and photosensitizing (e.g., exhibiting a sensitizing effect upon light irradiation).

Description

Technical Field

[0001] The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film and a method for manufacturing the same, and a liquid crystal element. Background Art

[0002] As the polymer component of the liquid crystal alignment film, polyimide is generally used for reasons such as high heat resistance. On the other hand, polyimide has low solubility in solvents, so it is believed that when a larger hydrophobic group (mesogen structure, etc.) is introduced into the polymer side chain, the solubility is insufficient and the coating property is reduced. Therefore, it is proposed to use acrylic polymers or styrene-maleimide polymers instead of polyimide as the material of the liquid crystal alignment film (for example, refer to patent document 1).

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] [Patent Document 1] International Publication No. 2018 / 074547 Summary of the invention

[0006] [Problems to be solved by the invention]

[0007] The liquid crystal alignment film is usually formed on the substrate by applying a liquid crystal alignment agent in which a polymer component is dissolved or dispersed in a solvent to a substrate and heating it at a high temperature (e.g., 200°C to 250°C). Therefore, when the heat resistance of the polymer component is insufficient, there is a concern that the polymer component may be thermally decomposed due to the heating treatment during film formation, thereby causing poor display, or the components produced by thermal decomposition may become impurities and reduce reliability. It is believed that such concerns are particularly prone to occur in areas where the film thickness of the liquid crystal alignment film becomes thinner due to, for example, poor coating. On the other hand, further high quality is required for liquid crystal elements, and it is required to show the desired pretilt angle characteristics (hereinafter also referred to as "pretilt angle stability") even when the film thickness of the liquid crystal alignment film becomes thinner due to poor coating during the formation of the alignment film.

[0008] In addition, when components produced by thermal decomposition caused by heating at a relatively high temperature remain as impurities in the film, there is a concern that the performance of the liquid crystal element may be reduced due to the impurities in the film, i.e., poor long-term heat resistance, due to long-term exposure of the liquid crystal element to a high temperature environment.

[0009] The present invention has been made in view of the above circumstances, and a main object thereof is to provide a liquid crystal aligning agent which can obtain a liquid crystal element having a stable pretilt angle and excellent long-term heat resistance even when the film thickness of the liquid crystal aligning film is reduced due to coating failure or the like.

[0010] [Technical means to solve the problem]

[0011] The present invention adopts the following means to solve the above-mentioned problems.

[0012] <1> A liquid crystal alignment agent, comprising a polymer [P], wherein the polymer [P] is an addition polymer having a partial structure in the polymer side chain that can exhibit at least one of a free radical generating function that generates free radicals upon light irradiation and a photosensitizing function that exhibits a sensitizing effect upon light irradiation, or a polymerizable carbon-carbon unsaturated bond, wherein the polymer [P] has at least one selected from the group consisting of a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula (4).

[0013] [Chemistry 1]

[0014]

[0015] (In formula (1), R 1 and R 2 are each independently a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom, or R 1 and R 2 Bonded to each other and to R 1 and R 2 The carbon atoms bonded together form a ring structure. 1 A partial structure having at least one of a radical generating function of generating radicals by light irradiation and a photosensitizing function of showing a sensitizing effect by light irradiation, or a monovalent group having a polymerizable carbon-carbon unsaturated bond. 3 is a monovalent substituent. m1 is an integer of 0 to 4. n1 is an integer of 0 to 2. When m1 is 2 or more, a plurality of R 3 The "*" indicates a bonding bond.

[0016] In formula (2), R 4 and R 5 are each independently a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom, or R 4 and R 5 Bonded to each other and to R 4 and R 5 The carbon atoms bonded together form a ring structure. 6 is a hydrogen atom or a monovalent organic group. 2A partial structure having at least one of a radical generating function of generating radicals by light irradiation and a photosensitizing function of showing a sensitizing effect by light irradiation, or a monovalent group having a polymerizable carbon-carbon unsaturated bond. 7 is a monovalent substituent. m2 is an integer of 0 to 4. n2 is an integer of 0 to 2. When m2 is 2 or more, multiple R 7 The "*" indicates a bonding bond.

[0017] In formula (3), R 8 A hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced with a halogen atom. 3 A partial structure having at least one of a radical generating function of generating radicals by light irradiation and a photosensitizing function of showing a sensitizing effect by light irradiation, or a monovalent group having a polymerizable carbon-carbon unsaturated bond. 9 is a monovalent substituent. m3 is an integer from 0 to 4. When m3 is 2 or more, multiple R 9 The "*" indicates a bonding bond.

[0018] In formula (4), R 10 Z is a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is substituted with a halogen atom. 1 X is an oxygen atom or -NH-. 4 A partial structure having at least one of a free radical generating function that generates free radicals by light irradiation and a photosensitizing function that exhibits a sensitizing effect by light irradiation, or a monovalent group having a polymerizable carbon-carbon unsaturated bond. "*" indicates a bonding bond.)

[0019] <2> A liquid crystal aligning film formed using the liquid crystal aligning agent according to <1> above.

[0020] <3> A liquid crystal element comprising the liquid crystal alignment film according to <2>.

[0021] <4> A method for manufacturing a liquid crystal element, comprising: a step of applying the liquid crystal alignment agent of <1> onto each conductive film in a pair of substrates having a conductive film to form a coating film; a step of arranging a pair of substrates formed with the coating films in a manner such that the coating films face each other with a liquid crystal layer in between to construct a liquid crystal unit; and a step of irradiating the liquid crystal unit with light while applying a voltage between the conductive films.

[0022] [Effects of the Invention]

[0023] According to the liquid crystal aligning agent of the present invention, even when the film thickness of the liquid crystal aligning film becomes thin due to coating failure or the like, a liquid crystal element having a stable pretilt angle and excellent long-term heat resistance can be obtained. DETAILED DESCRIPTION

[0024] The following is a detailed description of matters related to the form of the present disclosure. In addition, in this specification, the so-called "hydrocarbon group" means a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group. The so-called "chain hydrocarbon group" refers to a straight-chain hydrocarbon group and a branched hydrocarbon group that does not contain a cyclic structure but is only composed of a chain structure. Among them, it can be saturated or unsaturated. The so-called "alicyclic hydrocarbon group" refers to a hydrocarbon group that only contains the structure of alicyclic hydrocarbon as a ring structure and does not contain an aromatic ring structure. Among them, it is not necessary to be composed only of the structure of alicyclic hydrocarbons, and a group having a chain structure in a part thereof is also included. The so-called "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. Among them, it is not necessary to be composed only of an aromatic ring structure, and a chain structure or an alicyclic hydrocarbon structure may also be included in a part thereof. The so-called "main chain" of a polymer refers to the longest "trunk" part in the atomic chain of the polymer. The so-called "side chain" of a polymer refers to the part branching from the "trunk" of the polymer. The "organic group" refers to an atomic group formed by removing any hydrogen atoms from a compound containing carbon (ie, an organic compound).

[0025] Liquid crystal alignment agent

[0026] The liquid crystal aligning agent of the present disclosure contains the following polymer [P].

[0027] Polymer [P]: A polymer having a partial structure in the polymer side chain that can exhibit at least one of a free radical generating function of generating free radicals by light irradiation and a photosensitizing function of exhibiting a sensitizing effect by light irradiation, or an addition polymer of a polymerizable carbon-carbon unsaturated bond, and is a polymer having at least one structural unit (hereinafter also referred to as "first structural unit") selected from the group consisting of a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula (4).

[0028] [Chemistry 2]

[0029]

[0030] (In formula (1), R 1 and R 2 are each independently a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom, or R 1 and R 2 Bonded to each other and to R1 and R 2 The carbon atoms bonded together form a ring structure. 1 A partial structure having at least one of a radical generating function of generating radicals by light irradiation and a photosensitizing function of showing a sensitizing effect by light irradiation, or a monovalent group having a polymerizable carbon-carbon unsaturated bond. 3 is a monovalent substituent. m1 is an integer of 0 to 4. n1 is an integer of 0 to 2. When m1 is 2 or more, a plurality of R 3 The "*" indicates a bonding bond.

[0031] In formula (2), R 4 and R 5 are each independently a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom, or R 4 and R 5 Bonded to each other and to R 4 and R 5 The carbon atoms bonded together form a ring structure. 6 is a hydrogen atom or a monovalent organic group. 2 A partial structure having at least one of a radical generating function of generating radicals by light irradiation and a photosensitizing function of showing a sensitizing effect by light irradiation, or a monovalent group having a polymerizable carbon-carbon unsaturated bond. 7 is a monovalent substituent. m2 is an integer of 0 to 4. n2 is an integer of 0 to 2. When m2 is 2 or more, multiple R 7 Same as or different from each other.

[0032] “*” indicates a bonding bond.

[0033] In formula (3), R 8 A hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced with a halogen atom. 3 A partial structure having at least one of a radical generating function of generating radicals by light irradiation and a photosensitizing function of showing a sensitizing effect by light irradiation, or a monovalent group having a polymerizable carbon-carbon unsaturated bond. 9 is a monovalent substituent. m3 is an integer from 0 to 4. When m3 is 2 or more, multiple R 9 The "*" indicates a bonding bond.

[0034] In formula (4), R 10Z is a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is substituted with a halogen atom. 1 X is an oxygen atom or -NH-. 4 A partial structure having at least one of a free radical generating function that generates free radicals by light irradiation and a photosensitizing function that exhibits a sensitizing effect by light irradiation, or a monovalent group having a polymerizable carbon-carbon unsaturated bond. "*" indicates a bonding bond.)

[0035] <First structural unit>

[0036] In the above formulas (1) to (4), when X 1 , X 2 , X 3 and X 4 When the partial structure (hereinafter also referred to as "partial structure A") is a group having at least one of a radical generating function that generates radicals by light irradiation and a photosensitizing function that exhibits a sensitizing effect by light irradiation, the partial structure A is preferably a group having a photoinitiator structure that absorbs light and generates radicals. Examples of the photoinitiator structure include structures derived from known photoradical generators. Examples of the photoradical generator include compounds containing radical generating groups such as alkyl phenone compounds, benzoin compounds, ketal compounds, acetophenone compounds, benzophenone compounds, thioxanthone compounds, and anthraquinone compounds.

[0037] When X 1 , X 2 , X 3 and X 4 When X is a base with partial structure A, 1 , X 2 , X 3 and X 4 It is preferably a group represented by the following formula (a-1) or a group represented by the following formula (a-2).

[0038] [Chemistry 3]

[0039]

[0040] (In formula (a-1), Ar 1 and Ar 2 Ar 1 is a divalent aromatic ring group and Ar 2 is an alkyl group or a monovalent aromatic ring group, or Ar 1 and Ar 2 Combined with Ar 1 and Ar 2The carbonyl group to which it is bonded together forms a ring structure. 31 It is a single bond or a divalent organic group. “*” indicates a bonding bond. )

[0041] [Chemistry 4]

[0042]

[0043] (In formula (a-2), Ar 3 is a divalent aromatic ring group. 32 and R 33 are independently a monovalent organic group, or represent R 32 and R 33 Combined with R 32 and R 33 The carbon atoms bonded together form a ring structure. 34 is a hydroxyl group or a monovalent organic group. 35 It is a single bond or a divalent organic group. “*” indicates a bonding bond. )

[0044] Ar in the formula (a-1) 1 and Ar 2 , Ar in the formula (a-2) 3 The divalent aromatic ring group represented is a group formed by removing two hydrogen atoms from the ring part of a substituted or unsubstituted aromatic ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and the like, preferably a benzene ring. Examples of substituents that the aromatic ring may have include an alkyl group, an alkoxy group, a fluoroalkyl group having 1 to 6 carbon atoms, a fluorine atom, a hydroxyl group, and the like. As Ar 1 and Ar 2 The ring structure formed by mutual bonding includes two benzene rings connected via -O-, -S-, carbonyl or -NR 36 -(R 36 A structure in which a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms is bonded. The same shall apply hereinafter).

[0045] As R in the formula (a-2) 32 ~R 34 Examples of the monovalent organic group represented by include an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a benzyl group, a phenethyl group, a phenyloxy group, a phenylalkyloxy group, -NR 39 R 40 (Among them, R 39 and R 40 Each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms), a nitrogen-containing heterocyclic group, etc., and any hydrogen atom possessed by these groups may be substituted. Examples of the substituent include a fluorine atom, a hydroxyl group, etc. 32 and R 33 Examples of the ring structure formed by bonding to each other include a cycloalkyl group having 4 to 10 carbon atoms.

[0046] In the formula (a-1), R 31 and R represented by formula (a-2) 35 In the example, the divalent organic group includes a divalent hydrocarbon group having 1 to 20 carbon atoms, an arbitrary methylene group possessed by the hydrocarbon group, and an -O-, -S- or -NR 36 -substituted carbon number 2 to 20 groups, arbitrary hydrogen atoms possessed by hydrocarbon groups are substituted with fluorine atoms, alkoxy groups, hydroxyl groups, etc. When R 31 , R 35 When it is a divalent organic group, it preferably has 1 to 10 carbon atoms, and more preferably has 1 to 5 carbon atoms.

[0047] In the case of a thin liquid crystal alignment film, from the viewpoint of achieving both pretilt angle stability and ease of production, R 31 , R 35 Preferred examples include groups represented by the following formula (r-1).

[0048] * 1 -R 38 -Z 2 -*…(r-1)

[0049] (In formula (r-1), R 38 Z is a divalent organic group. 2 -O-, * 2 -COO-,* 2 -OCO-,* 2 -NH-CO-,* 2 -CO-NH- or * 2 -NH-COO-. "* 2 " indicates that the 38 The bonding bond of 1 " indicates that the 1 The “*” indicates a bonding bond. )

[0050] When X 1 , X 2 , X 3 and X 4 With partial structure A, about X 1 , X 2 , X 3 and X 4 As specific examples, as the group having a partial structure represented by the formula (a-1), the groups represented by the following formulas (a-1-1) to (a-1-5) can be listed; as the group represented by the formula (a-2), the groups represented by the following formulas (a-2-1) to (a-2-9) can be listed.

[0051] [Chemistry 5]

[0052]

[0053] (Where R 31 It is a single bond or a divalent group. “*” indicates a bonding bond. )

[0054] [Chemistry 6]

[0055]

[0056] (Where R 35 It is a single bond or a divalent group. “*” indicates a bonding bond. )

[0057] When X 1 , X 2 , X 3 and X 4 When X is a monovalent group having a polymerizable carbon-carbon unsaturated bond, 1 , X 2 , X 3 and X 4 , for example, the group represented by the following formula (a-3) can be mentioned.

[0058] *-R 37 -D 1 …(a-3)

[0059] (In formula (a-3), D 1 R is (meth)acryloyl, vinyl, vinylphenyl or vinyl ether. 37 is a single bond or a divalent organic group. )

[0060] In the formula (a-3), R 37 In the example, the divalent organic group includes a divalent hydrocarbon group having 1 to 20 carbon atoms, an arbitrary methylene group possessed by the hydrocarbon group, and an -O-, -S- or -NR 36 -substituted carbon number 2 to 20 group, arbitrary hydrogen atom possessed by hydrocarbon group is substituted by fluorine atom, alkoxy group, hydroxyl group etc. In addition, in this specification, "(meth)acrylic acid" means including "acrylic acid" and "methacrylic acid". "(meth)acryloyl" means including "acryloyl" and "methacryloyl".

[0061] In the formula (1), R 1 and R 2 , R in formula (2) 4 and R 5 In the example, the hydrocarbon group having 1 to 10 carbon atoms includes a chain or branched alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 4 to 10 carbon atoms, a phenyl group, a methylphenyl group, and the like. 1 and R2 or R 3 and R 4 Examples of the ring structure formed by bonding to each other include cycloalkyl groups having 4 to 10 carbon atoms. From the viewpoint of further improving the effects of improving the long-term heat resistance and pretilt angle stability of the liquid crystal element, n1 and n2 are preferably single bonds.

[0062] When R in the formula (2) 6 When it is a monovalent organic group, examples of the monovalent organic group include: a monovalent hydrocarbon group having 1 to 30 carbon atoms, wherein at least one methylene group of the hydrocarbon group is substituted by -O-, -CO-, -COO- or -NR 20 -(where R 20 a hydrogen atom or a monovalent hydrocarbon group) substituted (hereinafter also referred to as "group α"), a monovalent hydrocarbon group having 1 to 30 carbon atoms or a group in which at least one hydrogen atom of the group α is substituted with a fluorine atom or a cyano group, and the like.

[0063] As R in the formula (1) 3 , R in the formula (2) 7 , and R in the formula (3) 9 The monovalent substituent of may include an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 4 to 10 carbon atoms, a phenyl group, an alkoxy group having 1 to 10 carbon atoms, a halogen atom, a cyano group, etc. m1 to m3 are each preferably 0 to 2, and more preferably 0 or 1.

[0064] In the formula (3), R 8 And R in formula (4) 10 Preferred is a hydrogen atom, a fluorine atom, an alkyl group having 1 to 3 carbon atoms, or a fluoroalkyl group having 1 to 3 carbon atoms.

[0065] From the viewpoint of further improving the effect of improving the long-term heat resistance of the liquid crystal element, the first structural unit is preferably at least one selected from the group consisting of the partial structure represented by the formula (1), the partial structure represented by the formula (2), and the partial structure represented by the formula (3). In addition, from the viewpoint of obtaining a liquid crystal alignment film that exhibits a desired pretilt angle even when it becomes a thin film, the first structural unit preferably has a group represented by the formula (a-1) or the formula (a-2), and more preferably has a group represented by the formula (a-2).

[0066] Specific examples of the first structural unit include structural units represented by the following formula (U1-1) to formula (U1-21), and the like.

[0067] [Chemistry 7]

[0068]

[0069] [Chemistry 8]

[0070]

[0071] (Where X 5 It is a monovalent group represented by any one of the above formulas (a-1-1) to (a-1-5) and (a-2-1) to (a-2-9). "*" represents a bonding bond.

[0072] In the polymer [P], the preferred range of the content ratio of the first structural unit is different depending on whether the polymer [P] contains the following second structural unit. In the case where the polymer [P] contains the first structural unit and the second structural unit, the content ratio of the first structural unit in the polymer [P] is preferably 1 mol% or more, more preferably 2 mol% or more, and further preferably 5 mol% or more relative to the total amount of the structural units constituting the polymer [P]. In addition, the content ratio of the first structural unit is preferably 50 mol% or less, more preferably 40 mol% or less, and further preferably 30 mol% or less relative to the total amount of the structural units constituting the polymer [P]. If the content ratio of the first structural unit is within the above range, even if the film thickness of the liquid crystal alignment film becomes thin due to poor coating during the formation of the alignment film, the desired pretilt angle can be displayed, and the effect of improving the long-term heat resistance of the liquid crystal element can be improved, which is preferred in this respect.

[0073] In the case where the polymer [P] does not contain the second structural unit, the content ratio of the first structural unit in the polymer [P] is preferably 10 mol% or more, more preferably 20 mol% or more, and further preferably 25 mol% or more relative to the total amount of the structural units constituting the polymer [P]. In addition, the content ratio of the first structural unit is preferably 80 mol% or less, more preferably 70 mol% or less relative to the total amount of the structural units constituting the polymer [P]. If the content ratio of the first structural unit is within the above range when the polymer [P] does not contain the second structural unit, the desired pretilt angle is exhibited even when the film thickness of the liquid crystal alignment film is reduced, and the long-term heat resistance of the liquid crystal element is greatly improved, which is preferred.

[0074] <Second structural unit>

[0075] The polymer [P] preferably includes the first structural unit and further includes a structural unit having at least any one of the following (a) and (b) (hereinafter also referred to as a “second structural unit”):

[0076] (a) a non-photosensitive monovalent group having at least one of two or more aromatic rings and aliphatic rings (hereinafter also referred to as "non-photosensitive group B");

[0077] (b) a non-photosensitive monovalent group having an alkyl group, an alkoxy group, a fluoroalkyl group or a fluoroalkoxy group having at least 5 carbon atoms (excluding the group corresponding to (a). Hereinafter, also referred to as "non-photosensitive group C"). Since the polymer [P] also includes a second structural unit, a liquid crystal element having a high reliability and more stable display of a desired pretilt angle can be obtained even when the film thickness of the liquid crystal alignment film is reduced due to poor coating, etc., which is preferred in this respect.

[0078] From the viewpoint of taking into account both the liquid crystal orientation and the solubility of the polymer [P], the total number of aromatic rings and aliphatic rings possessed by the non-photosensitive group B is preferably two or more, and more preferably two to six. In addition, when the ring possessed by the non-photosensitive group B is a condensed ring, the number of monocyclic rings constituting the condensed ring represents the total number of aromatic rings and aliphatic rings possessed by the non-photosensitive group B. For example, a cholesteryl group is a group having four aliphatic rings, and thus corresponds to a non-photosensitive monovalent group having at least one of an aromatic ring and an aliphatic ring totaling two or more.

[0079] Preferred specific examples of the non-photosensitive group B include a group represented by the following formula (8). The group represented by the following formula (8) is preferred because it is less likely to be thermally decomposed and can further improve the long-term heat resistance of the liquid crystal element.

[0080] A 1 -B 1 -L 1 -B 2 -L 2 -*…(8)

[0081] (In formula (8), A 1 B is a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a fluoroalkyl group having 1 to 20 carbon atoms, or a fluoroalkoxy group having 1 to 20 carbon atoms. 1 L is a divalent group represented by any one of the following formulas (1-1) to (1-8). 1 B is a single bond or a divalent group represented by any one of the following formulae (2-1) to (2-6). 2 is a single bond or a divalent aromatic ring group. 2 It is a divalent group represented by any one of the following formulas (3-1) to (3-9). "*" represents a bonding bond.

[0082] [Chemistry 9]

[0083]

[0084] [Chemistry 10]

[0085]

[0086] [Chemistry 11]

[0087]

[0088] In the formula (8), in A 1 When it is an alkyl group, alkoxy group, fluoroalkyl group or fluoroalkoxy group having 1 to 20 carbon atoms, they are preferably linear. 1 It is preferably an alkyl group, alkoxy group, fluoroalkyl group or fluoroalkoxy group having 2 to 20 carbon atoms, and more preferably an alkyl group, alkoxy group, fluoroalkyl group or fluoroalkoxy group having 3 to 15 carbon atoms.

[0089] When B 2 When it is a divalent aromatic ring group, the aromatic ring group is preferably a substituted or unsubstituted phenylene group or naphthylene group, and more preferably a phenylene group. Examples of the substituents that the aromatic ring group may have include a methyl group, a halogen atom, and the like.

[0090] Specific examples of the group represented by the formula (8) include groups represented by the following formulae (m2-1) to (m2-16), and the like.

[0091] [Chemistry 12]

[0092]

[0093] [Chemistry 13]

[0094]

[0095] (In formula (m2-1) to formula (m2-16), A 1 It has the same meaning as the above formula (8). "*" represents a bonding bond.)

[0096] The non-photosensitive group C is a non-photosensitive monovalent group having an alkyl group, an alkoxy group, a fluoroalkyl group or a fluoroalkoxy group with a carbon number of 5 or more. The alkyl group, alkoxy group, fluoroalkyl group and fluoroalkoxy group possessed by the non-photosensitive group C are preferably straight-chain. As specific examples thereof, the alkyl group can be listed as: n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, n-nonadecyl, etc. As an alkoxy group, a group formed by bonding the above-exemplified alkyl group and an oxygen atom can be listed. As a fluoroalkyl group, a group in which at least one hydrogen atom in the above-exemplified alkyl group is substituted by a fluorine atom can be listed. As a fluoroalkoxy group, a group in which at least one hydrogen atom in the above-exemplified alkyl group and an oxygen atom is substituted by a fluorine atom can be listed.

[0097] The non-photosensitive group C may also be a monovalent group formed by bonding an alkyl group, an alkoxy group, a fluoroalkyl group or a fluoroalkoxy group having a carbon number of 5 or more to an aromatic ring or an aliphatic ring. The ring possessed by the non-photosensitive group C is preferably a benzene ring or a cyclohexane ring, and more preferably a benzene ring. The non-photosensitive group C has one ring.

[0098] The alkyl group, alkoxy group, fluoroalkyl group and fluoroalkoxy group of the non-photosensitive group C preferably have 6 or more carbon atoms, particularly preferably 8 or more carbon atoms, from the viewpoint of further improving the pretilt angle stability of the liquid crystal alignment film when formed into a thin film.

[0099] In terms of obtaining a liquid crystal element with high reliability that can more stably exhibit a desired pretilt angle even when the thickness of the liquid crystal orientation film becomes thinner, the second structural unit possessed by the polymer [P] is preferably a non-photosensitive group B, and is particularly preferably at least one structural unit selected from the group consisting of a structural unit represented by the following formula (5), a structural unit represented by the following formula (6), and a structural unit represented by the following formula (7).

[0100] [Chemistry 14]

[0101]

[0102] (In formula (5), R 11 and R 12 are each independently a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom, or R 11 and R 12 Bonded to each other and to R 11 and R 12 The carbon atoms bonded together form a ring structure. 1 It is a non-photosensitive monovalent group having at least one of two aromatic rings and aliphatic rings in total. 13 is a monovalent substituent. m4 is an integer of 0 to 4. n3 is an integer of 0 to 2. When m4 is 2 or more, a plurality of R 13 The "*" indicates a bonding bond.

[0103] In formula (6), R 14 and R 15 are each independently a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom, or R 14 and R 15 Bonded to each other and to R 14 and R 15 The carbon atoms bonded together form a ring structure.16 Y is a hydrogen atom or a monovalent organic group. 2 It is a non-photosensitive monovalent group having at least one of two aromatic rings and aliphatic rings in total. 17 is a monovalent substituent. m5 is an integer of 0 to 4. n4 is an integer of 0 to 2. When m5 is 2 or more, a plurality of R 17 The "*" indicates a bonding bond.

[0104] In formula (7), R 18 A hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is substituted with a halogen atom. 3 It is a non-photosensitive monovalent group having at least one of two aromatic rings and aliphatic rings in total. 19 is a monovalent substituent. m6 is an integer from 0 to 4. When m6 is 2 or more, a plurality of R 19 The same or different. "*" indicates a bonding bond. )

[0105] In the formula (5), Y 1 , Y in the formula (6) 2 , and Y in the formula (7) 3 It is a non-photosensitive monovalent group (non-photosensitive group B) having at least one of two aromatic rings and aliphatic rings in total. Specific examples and preferred examples of the non-photosensitive group B are the same as those of the non-photosensitive group B included in the second structural unit.

[0106] In the formula (5), R 11 , R 12 , R 13 , n3, m4 are respectively applicable to R in the formula (1) 1 , R 2 , R 3 , n1, and m1.

[0107] In the formula (6), R 14 , R 15 , R 16 , R 17 , n4, m5 are respectively applicable to R in the formula (2) 4 , R 5 , R 6 , R 7 Description of , n2, and m2.

[0108] In the formula (7), R 18 , R 19 , m6 are respectively applicable to R in the formula (3) 8 , R9 , description of m3.

[0109] Specific examples of the second structural unit include: X in the structural units represented by the formula (U1-1) to the formula (U1-17) is 5 is a structural unit of a base represented by any one of the formulae (m2-1) to (m2-16); in the structural units represented by the formulae (U1-1) to (U1-17), X in the formula 5 A preferred specific example of the second structural unit is a structural unit represented by each of the formulae (U1-1) to (U1-17): 5 This is a structural unit of a group represented by any one of the formulas (m2-1) to (m2-16).

[0110] When the polymer [P] includes the second structural unit, the content ratio of the second structural unit is preferably 1 mol% or more, more preferably 2 mol% or more, and further preferably 5 mol% or more relative to the total amount of the structural units constituting the polymer [P]. In addition, when the polymer [P] includes the second structural unit, the content ratio of the second structural unit is preferably 40 mol% or less, more preferably 35 mol% or less, and further preferably 30 mol% or less relative to the total amount of the structural units constituting the polymer [P]. If the content ratio of the second structural unit is within the above range, the improvement effect of the pretilt angle stability and the long-term heat resistance can be further improved, which is preferred in this respect.

[0111] <Third structural unit>

[0112] The polymer [P] preferably also contains a structural unit having at least one selected from the group consisting of a cyclic ether group and a cyclic carbonate group (hereinafter also referred to as a "third structural unit"). In the case where the polymer [P] has a third structural unit, the pretilt angle stability and heat resistance of the liquid crystal alignment film can be improved by reacting the cyclic ether group or cyclic carbonate group in the third structural unit with the carboxyl group, hydroxyl group, amino group, etc. of the components contained in the liquid crystal alignment agent, which is preferred in this respect. The cyclic ether group preferably has 3 to 7 ring members, and in terms of high reactivity, it is more preferably at least one of an oxetane group and an oxirane propyl group. In addition, in this specification, "epoxy groups" including oxetane groups and oxirane propyl groups are also referred to.

[0113] The polymer [P] having the third structural unit can be obtained, for example, by using an unsaturated monomer having at least one of a cyclic ether group and a cyclic carbonate group (hereinafter also referred to as a "third monomer") as a monomer providing the third structural unit during the synthesis of the polymer [P]. Examples of the third monomer include maleimide compounds, styrene compounds, (meth) acrylic acid compounds, and the like.

[0114] Specific examples of the third monomer include compounds having a cyclic ether group: (3-ethyloxetane-3-yl)methyl (meth)acrylate, N-(4-glycidyloxyphenyl)maleimide, N-glycidylmaleimide, 3-(glycidyloxymethyl)styrene, 4-(glycidyloxymethyl)styrene, 4-glycidyl-α-methylstyrene, glycidyl (meth)acrylate, α-ethyl glycidyl acrylate, α-n-propyl glycidyl acrylate, α-n-butyl glycidyl acrylate, 3,4-epoxybutyl (meth)acrylate, α-ethyl acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 6,7-epoxyheptyl (meth)acrylate, α-ethyl acrylate, 6,7-epoxyheptyl, 4-hydroxybutyl glycidyl (meth)acrylate, etc.

[0115] Examples of compounds having a cyclic carbonate group include (2-oxo-1,3-dioxolan-4-yl)methyl (meth)acrylate, 2-((2-oxo-1,3-dioxolan-4-yl)methoxy)ethyl (meth)acrylate, etc. In addition, when synthesizing the polymer [P], one of these monomers may be used alone as the third monomer, or two or more monomers may be used in combination.

[0116] When the polymer [P] contains a third structural unit, the content of the third structural unit is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 20 mol% or more relative to the total amount of the structural units constituting the polymer [P]. In addition, when the polymer [P] contains a third structural unit, the content of the third structural unit is preferably 80 mol% or less, more preferably 75 mol% or less, and further preferably 70 mol% or less relative to the total amount of the structural units constituting the polymer [P]. By having the content of the third structural unit within the above range, a cross-linked structure can be appropriately formed between the components, and the stability of the pretilt angle can be ensured even in the case of a thin film of the liquid crystal alignment film. In addition, the effect of improving long-term heat resistance can be improved, which is preferred in terms of the above aspects.

[0117] <Fourth structural unit>

[0118] The polymer [P] preferably further comprises the following structural unit (hereinafter also referred to as the "fourth structural unit"): the structural unit has a functional group (hereinafter also referred to as the "reactive functional group") that can form a bond between compounds and is different from the oxetane group and the oxetane group. As the reactive functional group possessed by the fourth structural unit, a functional group that reacts with at least one of the oxetane group and the oxetane group by heating (hereinafter also referred to as the "functional group D") can be cited. In the case where the polymer [P] has the functional group D, the improvement effect of the liquid crystal orientation (especially the pretilt angle stability in the film) can be fully obtained, which is preferred in this respect.

[0119] Examples of the functional group D include a carboxyl group, a protected carboxyl group, a hydroxyl group, a protected hydroxyl group, an isocyanate group, a protected isocyanate group, an amino group, a protected amino group, and an alkoxymethyl group. Among them, the functional group D is preferably at least one selected from the group consisting of a carboxyl group, a protected carboxyl group, an amino group, and a protected amino group in terms of good storage stability and high reactivity with an oxetane ring and an oxirane ring by heating.

[0120] When the reactive functional group possessed by the fourth structural unit is at least one selected from the group consisting of a carboxyl group, a protected carboxyl group, an amino group, and a protected amino group, a cross-linked structure is formed by reacting with a functional group possessed by a component contained in the liquid crystal alignment agent (for example, an oxetane group or an oxetane group possessed by the polymer [P], or an amino group or a hydroxyl group, a carboxyl group, etc. possessed by a polymer different from the polymer [P]), thereby improving the pretilt angle stability and heat resistance of the liquid crystal alignment film, which is preferred in this respect.

[0121] The protected carboxyl group is not particularly limited as long as it is a group that is released by heat to generate a carboxyl group. Preferred specific examples of the protected carboxyl group include a structure represented by the following formula (4), an acetal ester structure of a carboxylic acid, and a ketal ester structure of a carboxylic acid.

[0122] [Chemistry 15]

[0123]

[0124] (In formula (4), R 41 , R 42 and R 43 Satisfies the following (1) or (2).

[0125] (1)R 41 , R 42 and R 43 Each independently represents an alkyl group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms.

[0126] (2)R41 and R 42 Indicates the combination with R 41 and R 42 The carbon atoms to which the bond is attached together form an alicyclic hydrocarbon structure or a cyclic ether structure having 4 to 20 carbon atoms. 43 It is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0127] “*” indicates a bonding bond. )

[0128] Specific examples of the structure represented by the formula (4) include tert-butoxycarbonyl, 1-cyclopentylethoxycarbonyl, 1-cyclopentyl-2-methylpropoxycarbonyl, 1-cyclohexylethoxycarbonyl, 1-norbornylethoxycarbonyl, 1-phenylethoxycarbonyl, 1-(1-naphthyl)ethoxycarbonyl, 1-benzylethoxycarbonyl, and 1-phenylethylethoxycarbonyl.

[0129] Specific examples of the acetal ester structure of carboxylic acid include 1-methoxyethoxycarbonyl, 1-ethoxyethoxycarbonyl, 1-propoxyethoxycarbonyl, 1-butoxyethoxycarbonyl, 1-cyclohexyloxyethoxycarbonyl, 1-phenoxyethoxycarbonyl, 2-tetrahydrofuranyloxycarbonyl, and 2-tetrahydropyranyloxycarbonyl.

[0130] Specific examples of the ketal ester structure of carboxylic acid include 1-methyl-1-methoxyethoxycarbonyl, 1-methyl-1-ethoxyethoxycarbonyl, 1-methyl-1-propoxyethoxycarbonyl, 1-methyl-1-butoxyethoxycarbonyl, 1-methyl-1-cyclohexyloxyethoxycarbonyl, 2-(2-methyltetrahydrofuranyl)oxycarbonyl, 2-(2-methyltetrahydropyranyl)oxycarbonyl, 1-methoxycyclopentyloxycarbonyl, and 1-methoxycyclohexyloxycarbonyl.

[0131] The protected amino group is a group that is separated by heat and generates an amino group. As a specific example of a heat-detachable group that is separated by heat, for example, tert-butoxycarbonyl, benzyloxycarbonyl, 1,1-dimethylpropynyloxycarbonyl, 1,1-dimethyl-2-haloethyloxycarbonyl, allyloxycarbonyl, vinyloxycarbonyl, cyclohexyloxycarbonyl, methylcyclohexyloxycarbonyl, 2-(trimethylsilyl)ethoxycarbonyl, 9-fluorenylmethyloxycarbonyl, 2,2,2-trichloroethoxycarbonyl, phthaloyl, p-toluenesulfonyl, 2-nitrobenzenesulfonyl, etc. Among these, tert-butoxycarbonyl and 9-fluorenylmethyloxycarbonyl are preferred from the viewpoint of being separated by heating during film formation, and tert-butoxycarbonyl (Boc group) is particularly preferred from the viewpoint of being excellent in heat-detachability and being able to reduce the residual amount of the separated structure in the film.

[0132] When the polymer [P] contains a fourth structural unit, the reactive functional group possessed by the fourth structural unit is preferably a carboxyl group or a protected carboxyl group, and more preferably a protected carboxyl group, in terms of high reactivity with cyclic ether groups and cyclic carbonate groups and good storage stability of the liquid crystal aligning agent.

[0133] The polymer [P] having the fourth structural unit can be obtained, for example, by polymerization reaction using an unsaturated monomer having a reactive functional group (hereinafter also referred to as "fourth monomer"), and examples of the fourth monomer include maleimide compounds, styrene compounds, (meth) acrylic acid compounds, and vinyl compounds.

[0134] Specific examples of these maleimide compounds include 3-(2,5-dioxo-3-pyrrolin-1-yl)benzoic acid, 4-(2,5-dioxo-3-pyrrolin-1-yl)benzoic acid, methyl 4-(2,5-dioxo-3-pyrrolin-1-yl)benzoate, and tert-butyl 4-(2,5-dioxopyrrol-1-yl)benzoate.

[0135] Examples of styrene compounds include 3-vinylbenzoic acid, 4-vinylbenzoic acid, 4-aminostyrene, and 4-(N-tert-butoxycarbonyl)styrene.

[0136] Examples of (meth)acrylic acid compounds include (meth)acrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, vinylbenzoic acid, crotonic acid, citraconic acid, mesaconic acid, itaconic acid, 3-maleimidobenzoic acid, 3-maleimidopropionic acid, (meth)acrylate 2-aminoethyl, and protected carbonyl group-containing compounds represented by the following formulas (m4-1) to (m4-12), respectively;

[0137] [Chemistry 16]

[0138]

[0139] (In formula (m4-1) to formula (m4-12), R 50 is a hydrogen atom or a methyl group.)

[0140] Examples of the vinyl compound include bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, etc. In the synthesis of the polymer [P], the fourth monomer may be used alone or in combination of two or more.

[0141] When the polymer [P] includes the fourth structural unit, the content ratio of the fourth structural unit is preferably 2 mol% or more, more preferably 5 mol% or more, and further preferably 10 mol% or more relative to the total amount of the structural units constituting the polymer [P]. In addition, when the polymer [P] includes the fourth structural unit, the content ratio of the fourth structural unit is preferably 65 mol% or less, more preferably 60 mol% or less, and further preferably 55 mol% or less relative to the total amount of the structural units constituting the polymer [P]. By having the content ratio of the fourth structural unit within the above range, a cross-linked structure can be appropriately formed between the functional group possessed by the third structural unit or the functional group possessed by a polymer different from the polymer [P], thereby improving the pretilt angle stability of the liquid crystal element and the improvement effect of long-term heat resistance, which is preferred in this respect.

[0142] <Other structural units>

[0143] The polymer [P] may further have a structural unit different from the first structural unit to the fourth structural unit (hereinafter also referred to as "other structural units"). Examples of monomers providing other structural units (hereinafter also referred to as "other monomers") include (meth)acrylic acid compounds such as alkyl (meth)acrylates, cycloalkyl (meth)acrylates, benzyl (meth)acrylates, and 2-hydroxyethyl (meth)acrylates; aromatic vinyl compounds such as styrene, methylstyrene, and divinylbenzene; conjugated diene compounds such as 1,3-butadiene and 2-methyl-1,3-butadiene; maleimide compounds such as N-methylmaleimide, N-cyclohexylmaleimide, and N-phenylmaleimide. As other monomers, one type may be used alone or two or more types may be used in combination.

[0144] In the polymer [P], the preferred range of the content ratio of the other structural units varies depending on whether the polymer [P] contains the second structural unit. When the polymer [P] contains the first structural unit and the second structural unit, the ratio of the other structural units in the polymer [P] is preferably 20 mol% or less, more preferably 15 mol% or less, relative to the total amount of the structural units constituting the polymer [P].

[0145] When the polymer [P] does not contain the first structural unit and does not contain the second structural unit, the proportion of other structural units in the polymer [P] is preferably 40 mol% or less, more preferably 35 mol% or less, relative to the total amount of structural units constituting the polymer [P].

[0146] In polymer [P], relative to the total amount of structural units constituting polymer [P], the proportion of structural units derived from maleimide compounds (i.e., the proportion of structural units derived from maleimide compounds in the first structural unit to the fourth structural unit and other structural units) is preferably 20 mol% or more. If it is 20 mol% or more, the improvement effect of the pretilt angle stability of the liquid crystal alignment film can be fully obtained while ensuring the solubility of polymer [P] and the coating property on the substrate, which is preferred in this respect. From the above point of view, relative to the total amount of structural units constituting polymer [P], the proportion of structural units derived from maleimide compounds is more preferably 25 mol% or more, and more preferably 30 mol% or more. In addition, from the point of view of suppressing the reduction of the liquid crystal orientation and voltage holding ratio of the liquid crystal element, relative to the total amount of structural units constituting polymer [P], the proportion of structural units derived from maleimide compounds is more preferably 95 mol% or less, and further preferably 90 mol% or less.

[0147] In the case of introducing structural units derived from styrene compounds into polymer [P], from the perspective of improving the heat resistance of the liquid crystal alignment film, relative to the total amount of structural units constituting the polymer [P], the proportion of structural units derived from styrene compounds (i.e., the proportion of structural units derived from styrene compounds in the first structural unit to the fourth structural unit and other structural units) is preferably 1 mol% or more, more preferably 2 mol% or more, and further preferably 5 mol% or more. In addition, relative to the total amount of structural units constituting the polymer [P], the proportion of structural units derived from styrene compounds is preferably 90 mol% or less, more preferably 80 mol% or less. Furthermore, in the case of setting the polymer [P] as a copolymer of a styrene compound and a maleimide compound, a main chain structure with high heat resistance is formed by alternating copolymerization of styrene compounds and maleimide compounds, which can achieve a reduction in unreacted monomers after polymerization and a further improvement from main chain heat resistance to long-term heat resistance, which is preferred in this regard. From the above viewpoint, the ratio of the styrene compound and the maleimide compound constituting the polymer [P] is preferably 0.8 mol to 1.2 mol of the maleimide compound per 1 mol of the styrene compound.

[0148] From the viewpoint of forming a liquid crystal orientation film having high heat resistance and sufficiently ensuring the liquid crystal orientation and electrical properties of the liquid crystal element, the proportion of the structural units derived from the (meth)acrylic compound in the polymer [P] (i.e., the proportion of the structural units derived from the (meth)acrylic compound in the first to fourth structural units and other structural units) relative to the total amount of the structural units possessed by the polymer [P] is preferably 30 mol% or less, more preferably 25 mol% or less, and even more preferably 20 mol% or less.

[0149] <Synthesis of polymer [P]>

[0150] The polymer [P] is a polymer obtained by addition polymerization, and the details of its synthesis method are not particularly limited. The polymer [P] can be obtained, for example, by polymerizing the monomers in an organic solvent in the presence of a polymerization initiator (addition polymerization). As a polymerization initiator, a free radical polymerization initiator can be preferably used, and as a specific example thereof, for example, azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) can be listed. The proportion of the polymerization initiator used is preferably set to 0.01 to 30 parts by mass relative to 100 parts by mass of all monomers used in the reaction. As the organic solvent used, for example, alcohols, ethers, ketones, amides, esters, hydrocarbon compounds, etc. can be listed.

[0151] In the polymerization reaction, the reaction temperature is preferably set to 30°C to 120°C, and the reaction time is preferably set to 1 hour to 36 hours. The amount of organic solvent used (a) is preferably set to the total amount (b) of the monomers used in the reaction relative to the total amount (a+b) of the reaction solution to be 0.1% by mass to 60% by mass. For the reaction solution in which the polymer is dissolved, for example, the polymer [P] contained in the reaction solution can be separated and provided for the preparation of the liquid crystal alignment agent by applying a known separation method such as a method of injecting the reaction solution into a large amount of a poor solvent and drying the precipitate obtained under reduced pressure, and a method of removing the reaction solution by reduced pressure distillation using an evaporator.

[0152] The weight average molecular weight (Mw) of the polymer [P] measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1,000 to 300,000, and more preferably 2,000 to 100,000. The molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 10 or less, and more preferably 8 or less. In addition, the polymer [P] used in the preparation of the liquid crystal alignment agent may be only one kind or a combination of two or more kinds.

[0153] Depending on whether the polymer [P] contains the second structural unit, the preferred content ratio of the polymer [P] in the liquid crystal alignment agent is different. In the case where the polymer [P] contains the first structural unit and the second structural unit, from the perspective of obtaining a liquid crystal element that has good pretilt angle characteristics and excellent long-term heat resistance even when the liquid crystal alignment film becomes thinner than the desired film thickness due to poor coating, etc., relative to a total of 100 parts by mass of the solid component (i.e., components other than the solvent) in the liquid crystal alignment agent, it is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, and further preferably 5 parts by mass or more. In addition, relative to a total of 100 parts by mass of the solid component in the liquid crystal alignment agent, the content ratio of the polymer [P] in the liquid crystal alignment agent is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 25 parts by mass or less.

[0154] When the polymer [P] does not include the second structural unit, based on the same reasons as above, the content ratio of the polymer [P] is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and further preferably 0.1 parts by mass or more, relative to a total of 100 parts by mass of the solid components in the liquid crystal alignment agent. In addition, the content ratio of the polymer [P] in the liquid crystal alignment agent is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and further preferably 3 parts by mass or less, relative to a total of 100 parts by mass of the solid components in the liquid crystal alignment agent.

[0155] <Other ingredients>

[0156] The liquid crystal aligning agent of the present disclosure may further contain components other than the polymer [P] (hereinafter, also referred to as “other components”).

[0157] (aggregate[Q])

[0158] In order to further improve the liquid crystal orientation and electrical properties of the liquid crystal orientation film formed using the liquid crystal orientation agent, the liquid crystal orientation agent disclosed herein may also contain a polymer different from the polymer [P], that is, a polymer that does not contain the first structural unit (hereinafter also referred to as "polymer [Q]") as other components.

[0159] The main skeleton of polymer [Q] is not particularly limited, for example, polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine (polyenamine), polyurea, polyamide, polyamide-imide, polybenzoxazole precursor, polybenzoxazole, cellulose derivatives, polyacetal, etc. Among these, polymer [Q] is preferably selected from at least one of the group consisting of polyamic acid, polyamic acid ester and polyimide. It is believed that according to the blending system of polyamic acid etc. and polymer [P], the phase separation of polymer [P] and polymer [Q] can be easily produced in the liquid crystal alignment film, thereby making polymer [P] easily biased to exist in the upper layer. As a result, it is believed that a liquid crystal alignment film showing high pretilt angle stability that is not easily affected by film thickness differences can be obtained.

[0160] The polymer [Q] can be synthesized according to a known method. For example, polyamic acid can be obtained by reacting tetracarboxylic dianhydride with diamine. In addition, in this specification, "tetracarboxylic acid derivative" refers to the meaning of tetracarboxylic dianhydride, tetracarboxylic acid diester and tetracarboxylic acid diester dihalide.

[0161] The tetracarboxylic dianhydride used in the polymerization is not particularly limited, and various tetracarboxylic dianhydrides can be used. Specific examples thereof include aliphatic tetracarboxylic dianhydrides such as butanetetracarboxylic dianhydride and ethylenediaminetetraacetic dianhydride; 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2 Alicyclic tetracarboxylic dianhydrides such as furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, and cyclohexanetetracarboxylic dianhydride; aromatic tetracarboxylic dianhydrides such as pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, p-phenylenebis(trimellitic acid monoester anhydride), ethylene glycol bis(trimellitic anhydride), and 1,3-propylene glycol bis(trimellitic anhydride), in addition to these, tetracarboxylic dianhydrides described in Japanese Patent Laid-Open No. 2010-97188 can be used. In addition, the tetracarboxylic dianhydride can be used alone or in combination of two or more.

[0162] Examples of the diamine used in the polymerization include aliphatic diamines such as ethylenediamine and tetramethylenediamine; alicyclic diamines such as p-cyclohexanediamine and 4,4'-methylenebis(cyclohexylamine);

[0163] Dodecyloxydiaminobenzene, pentadecyloxydiaminobenzene, hexadecyloxydiaminobenzene, octadecyloxydiaminobenzene, cholesteryloxydiaminobenzene, cholesteryl diaminobenzoate, cholesteryl diaminobenzoate, lanosteryl 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, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylamine, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,5-bis(4-aminophenoxy)pentane, bis[2-(4 aromatic diamines such as adipic acid, bis(4-aminophenyl)amine, N,N-bis(4-aminophenyl)methylamine, N,N'-bis(4-aminophenyl)-benzidine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-(phenylenediisopropylidene)dianiline, 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)]diphenylamine, and compounds represented by the following formulas (5-0) to (5-10);

[0164] In addition to diaminoorganosiloxanes such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, diamines described in Japanese Patent Publication No. 2010-97188 can be used. In addition, as diamines, diamines formed by bonding a monovalent group of any one of formula (m2-1) to formula (m2-16) to diaminobenzene can also be used. In addition, diamines can be used alone or in combination of two or more.

[0165] [Chemistry 17]

[0166]

[0167] (In formula (5-0) to formula (5-4), n is an integer of 1 to 20.)

[0168] [Chemistry 18]

[0169]

[0170] The synthesis reaction of polyamic acid is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20°C to 150°C, and the reaction time is preferably 0.1 hour to 24 hours. As the organic solvent used in the reaction, for example, there can be mentioned: aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc. The amount of the organic solvent used is preferably set to an amount in which the total amount of tetracarboxylic dianhydride and diamine compound is 0.1% by mass to 50% by mass relative to the total amount of the reaction solution.

[0171] When the polymer [Q] is polyamic acid ester, the polyamic acid ester can be obtained, for example, by the following methods: a method of reacting the polyamic acid obtained above with an esterifying agent (such as methanol or ethanol, N,N-dimethylformamide diethyl acetal, etc.); a method of reacting a tetracarboxylic acid diester with a diamine compound in the presence of a suitable dehydration catalyst; a method of reacting a tetracarboxylic acid diester dihalide with a diamine in the presence of a suitable base, etc.

[0172] When the polymer [Q] is a polyimide, the polyimide can be obtained, for example, by imidizing the polyamic acid obtained above by dehydration ring closure. The imidization rate of the polyimide is preferably 20% to 95%, more preferably 30% to 85%, and further preferably 40% to 80%. The imidization rate is expressed as a percentage of the ratio of the number of imide ring structures of the polyimide to the total number of amic acid structures and the number of imide ring structures.

[0173] When a solution having a concentration of 10% by mass is prepared, the solution viscosity of the polymer [Q] is preferably 10 mPa·s to 800 mPa·s, and more preferably 15 mPa·s to 500 mPa·s. 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 [Q] (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0174] The weight average molecular weight (Mw) of the polymer [Q] measured by GPC in terms of polystyrene is preferably 1,000 to 500,000, and more preferably 5,000 to 100,000. The molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the number average molecular weight (Mn) measured by GPC in terms of polystyrene is preferably 15 or less, and more preferably 10 or less. In addition, the polymer [Q] contained in the liquid crystal aligning agent may be only one type, or two or more types may be combined.

[0175] In the case where the polymer [P] does not include the second structural unit, the liquid crystal alignment agent of the present disclosure preferably includes the polymer [P] (i.e., the polymer including the first structural unit and not including the second structural unit) and includes as the polymer [Q] a polymer having at least one of the non-photosensitive group B and the non-photosensitive group C and not including the first structural unit (hereinafter also referred to as "polymer [Q1]"). In the case where the polymer [P] does not include the second structural unit, by including the polymer [P] and the polymer [Q1], a good pretilt angle characteristic can be exhibited in the obtained liquid crystal alignment film.

[0176] Among them, the non-photosensitive group possessed by the polymer [Q1] is particularly preferably the non-photosensitive group B, from the viewpoint of a higher effect of improving the pretilt angle stability in the thin-film liquid crystal alignment film. Specific examples and preferred examples of the non-photosensitive group B and the non-photosensitive group C are the same as those described above.

[0177] In terms of making it easy to generate phase separation between the polymer [P] and the polymer [Q1] in the liquid crystal alignment film, the polymer [Q1] is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide. When the polymer [Q1] is at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, the polymer can be obtained by, for example, polymerizing a diamine having a non-photosensitive group B or a non-photosensitive group C (hereinafter also referred to as a "vertical alignment diamine").

[0178] When the polymer [Q1] is at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, the content ratio of the structural unit derived from the vertical alignment diamine in the polymer [Q1] is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 20 mol% or more relative to the total amount of diamine constituting the polymer [Q1]. In addition, the content ratio of the structural unit derived from the vertical alignment diamine relative to the total amount of diamine constituting the polymer [Q1] is preferably 80 mol% or less, more preferably 70 mol% or less, and further preferably 60 mol% or less.

[0179] In the case of deploying polymer [Q] in the liquid crystal alignment agent of the present disclosure, the preferred range of the ratio of polymer [Q] to polymer [P] in the liquid crystal alignment agent is different depending on whether polymer [P] contains the second structural unit. In the case where polymer [P] contains the first structural unit and the second structural unit, the ratio of the content of polymer [P] to polymer [Q] is preferably 1 mass part or more, more preferably 2 mass parts or more, and further preferably 5 mass parts or more relative to 100 mass parts of polymer [Q]. In addition, the content of polymer [P] is preferably 40 mass parts or less, more preferably 30 mass parts or less, and further preferably 25 mass parts or less relative to 100 mass parts of polymer [Q]. By setting the content of polymer [P] to the range, a stable pretilt angle can be exhibited even when the thickness of the liquid crystal alignment film becomes thinner than the desired film thickness, and the long-term heat resistance of the liquid crystal element can be excellent, which is preferred in terms of the above aspects.

[0180] When polymer [P] does not include the first structural unit and does not include the second structural unit, the ratio of the content of polymer [P] to polymer [Q] (preferably polymer [Q1]) is preferably 0.05 mass parts or more, more preferably 0.1 mass parts or more, and further preferably 0.2 mass parts or more relative to 100 mass parts of polymer [Q]. In addition, the content of polymer [P] is preferably 20 mass parts or less, more preferably 15 mass parts or less, and further preferably 10 mass parts or less relative to 100 mass parts of polymer [Q]. By setting the content of polymer [P] to the range, a stable pretilt angle can be exhibited even when the thickness of the liquid crystal alignment film becomes thinner than the desired film thickness, and the long-term heat resistance of the liquid crystal element can be excellent, which is preferred in terms of the above aspects.

[0181] As other components that the liquid crystal alignment agent of the present disclosure may contain, in addition to the polymer [Q], for example, compounds having one or more epoxy groups in the molecule, compounds having two or more methylol groups in the molecule, functional silane compounds, compounds having one or more (meth)acryloyl groups in the molecule, antioxidants, metal chelate compounds, hardening accelerators, surfactants, fillers, dispersants, photosensitizers, etc. The proportions thereof may be appropriately selected according to each compound within the range that does not impair the effects of the present disclosure.

[0182] (Solvent)

[0183] The liquid crystal aligning agent is usually prepared as a liquid composition in which the polymer [P] and other components used as necessary are preferably dispersed or dissolved in an appropriate solvent.

[0184] Examples of the organic solvent 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, ethylene glycol-isopropyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isopentyl propionate, isopentyl isobutyrate, diisoamyl ether, ethylene carbonate, propylene carbonate, etc. They can be used alone or in combination of two or more.

[0185] 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) can be appropriately selected considering viscosity, volatility, etc., preferably in the range of 1% by mass to 10% by mass. That is, the liquid crystal alignment agent is applied to the surface of the substrate as described later, preferably heated, thereby forming a coating film as a liquid crystal alignment film or a coating film that becomes a liquid crystal alignment film. At this time, if the solid content concentration is more than 1% by mass, the film thickness of the coating film can be fully ensured, and a good liquid crystal alignment film can be easily obtained, which is preferred from this point of view. In addition, if the solid content concentration is less than 10% by mass, the film thickness of the coating film will 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, so that the coating property can be good.

[0186] As a preferred embodiment of the liquid crystal aligning agent of the present disclosure, the following embodiments <1> to <4> are mentioned. However, the embodiment of the liquid crystal aligning agent of the present disclosure is not limited to the following embodiments.

[0187] <1> A form in which a polymer [P] includes a polymer including a first constitutional unit, a second constitutional unit, and a third constitutional unit and, if necessary, other constitutional units, and a polyamic acid, a polyamic acid ester, or a polyimide is included as a polymer [Q].

[0188] <2> A form in which a polymer [P] includes a polymer including the first constitutional unit, the second constitutional unit, the third constitutional unit, and the fourth constitutional unit and, if necessary, other constitutional units, and a polyamic acid, a polyamic acid ester, or a polyimide is included as the polymer [Q].

[0189] <3> A form in which a polymer [P] includes a polymer including a first constitutional unit, a second constitutional unit, and a fourth constitutional unit and, if necessary, other constitutional units, and a polyamic acid, a polyamic acid ester, or a polyimide is included as a polymer [Q].

[0190] <4> A form in which a polymer [P] includes a polymer including a first constitutional unit and a fourth constitutional unit and, if necessary, other constitutional units, and a polyamic acid, a polyamic acid ester, or a polyimide is included as a polymer [Q1].

[0191] <5> A form in which a polymer [P] includes a polymer including a first constitutional unit, a third constitutional unit, and a fourth constitutional unit and, if necessary, other constitutional units, and a polyamic acid, a polyamic acid ester, or a polyimide is included as a polymer [Q1].

[0192] <6> A form in which a polymer [P] includes a first constitutional unit and a third constitutional unit and, if necessary, other constitutional units, and a polyamic acid, a polyamic acid ester, or a polyimide is included as a polymer [Q1].

[0193] Among the above aspects, <1>, <2>, <4> and <5> are preferred because they can provide a stable pretilt angle even when the thickness of the liquid crystal alignment film is thinner than the desired film thickness and can also provide excellent long-term heat resistance of the liquid crystal element.

[0194] 《Liquid crystal alignment film and liquid crystal element》

[0195] The liquid crystal alignment film of the present invention can be formed by a liquid crystal alignment agent prepared as described. In addition, the liquid crystal element of the present invention includes a liquid crystal alignment film formed using the liquid crystal alignment agent described. The action mode of the liquid crystal in the liquid crystal element is not particularly limited, for example, it can be applied to various modes such as twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA) (including vertical alignment-multi-domain vertical alignment (VA-MVA), vertical alignment-patterned vertical alignment (VA-PVA), etc.), in-plane switching (IPS), fringe field switching (FFS), optically compensated bend (OCB), polymer stabilized alignment (PSA), etc. The liquid crystal element can be produced, for example, by a method including the following steps 1 to 3. In step 1, the substrate used varies depending on the desired operation mode. Steps 2 and 3 are common to each operation mode.

[0196] (Step 1: Formation of coating film)

[0197] First, the liquid crystal alignment agent is applied to the substrate, and the coated surface is preferably heated to form a coating film on the substrate. As a substrate, for example, glass such as float glass and soda glass can be used; a transparent substrate containing plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly (alicyclic olefin). As a transparent conductive film disposed on the substrate surface, a NESA film (registered trademark of PPG Company, USA) containing tin oxide (SnO2) and an indium tin oxide (Indium Tin Oxide, ITO) film containing indium oxide-tin oxide (In2O3-SnO2) can be used. In the case of manufacturing a TN type, STN type or VA type liquid crystal element, two substrates provided with a patterned transparent conductive film are used. On the other hand, in the case of manufacturing an IPS type or FFS type liquid crystal element, a substrate provided with an electrode containing a transparent conductive film or a metal film patterned into a comb shape and an opposing substrate without an electrode are used. As a metal film, for example, a film containing a metal such as chromium can be used. The liquid crystal aligning agent is applied to the substrate on the electrode formation surface preferably by an offset printing method, a spin coating method, a roll coater method, or an inkjet printing method.

[0198] After the liquid crystal aligning agent is applied, it is preferably preheated (prebaked) for the purpose of preventing the applied liquid crystal aligning agent from dripping, etc. The prebaking temperature is preferably 30° C. to 150° C., more preferably 40° C. to 120° C. The prebaking time is preferably 0.25 minutes to 10 minutes.

[0199] Thereafter, a calcination (post-baking) process is implemented for the purpose of further removing the solvent and, if necessary, thermally imidizing the amic acid structure present in the polymer. The calcination temperature (post-baking temperature) at this time is preferably below 280°C, more preferably below 250°C. In addition, from the perspective of suppressing the reduction of liquid crystal orientation or reliability due to the influence of the residual solvent component in the film, the post-baking temperature is preferably above 80°C, more preferably above 90°C. The post-baking time is preferably 5 minutes to 150 minutes. The film thickness of the film thus formed is preferably 0.001μm to 1μm. After the liquid crystal alignment agent is applied to the substrate, the organic solvent is removed, thereby forming a liquid crystal alignment film, or a coating film of a liquid crystal alignment film.

[0200] (Process 2: Orientation Treatment)

[0201] In the case of manufacturing TN type, STN type, IPS type or FFS type liquid crystal elements, a process (orientation treatment) of imparting liquid crystal orientation ability to the coating formed in the process 1 is implemented. Thus, the orientation ability of the liquid crystal molecules is imparted to the coating to form a liquid crystal orientation film. As an orientation treatment, it is preferred to use a friction treatment in which the surface of the coating formed on the substrate is wiped with cotton or the like, or to irradiate the coating with light to impart a light orientation ability to the liquid crystal. In the case of manufacturing a vertically oriented liquid crystal element, the coating formed in the process 1 can be directly used as a liquid crystal orientation film, and in order to further improve the liquid crystal orientation ability, the coating can also be subjected to an orientation treatment.

[0202] The light irradiation in the photo-alignment treatment can be carried out by the following methods, etc.: a method of irradiating the coating after the post-baking process, a method of irradiating the coating after the pre-baking process and before the post-baking process, and a method of irradiating the coating during the heating process of the coating in at least any one of the pre-baking process and the post-baking process. In the photo-alignment treatment, as the radiation irradiated to the coating, for example, ultraviolet rays and visible light containing light with a wavelength of 150nm to 800nm ​​can be used. Preferably, ultraviolet rays containing light with a wavelength of 200nm to 400nm can be used. In the case where the radiation is polarized, it can be linearly polarized or partially polarized. In addition, when the radiation used is linearly polarized or partially polarized, the irradiation can be carried out from a direction perpendicular to the substrate surface, from an inclined direction, or by a combination of these. In the case of irradiating non-polarized radiation, the irradiation direction is set to an inclined direction.

[0203] As the light source used, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. can be used. The radiation irradiation amount is preferably 400 J / m 2 ~20,000J / m 2 , more preferably 1,000 J / m 2 ~5,000J / m 2 In order to improve the reactivity, the coating film may be irradiated with light while being heated.

[0204] When manufacturing the liquid crystal alignment film, the organic film subjected to the light irradiation treatment can be further heated. In addition, the organic film subjected to the light irradiation treatment can also be contacted with water, a water-soluble organic solvent, or a mixed solvent of water and a water-soluble organic solvent. As water-soluble organic solvents, for example, methanol, ethanol, 1-propanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone. After the contact process, the organic film can be heated.

[0205] (Step 3: Construction of Liquid Crystal Cell)

[0206] Two substrates with liquid crystal alignment films formed in the above manner are prepared, and liquid crystal is arranged between the two substrates arranged opposite to each other, thereby manufacturing a liquid crystal cell. When manufacturing a liquid crystal cell, for example, there can be listed: (1) two substrates are arranged opposite to each other with a gap (spacer) in a manner that the liquid crystal alignment films face each other, and the peripheral portions of the two substrates are bonded together using a sealant, and the liquid crystal is injected into the cell gap divided by the substrate surface and the sealant, and then the injection hole is sealed; (2) a sealant is applied to a predetermined location on one of the substrates formed with a liquid crystal alignment film, and then liquid crystal is dripped at a predetermined number of locations on the surface of the liquid crystal alignment film, and then another substrate is bonded in a manner that the liquid crystal alignment films face each other, and the liquid crystal is diffused on the entire surface of the substrate (liquid crystal dripping (one drop filling, ODF) method) and the like. Preferably, the manufactured liquid crystal cell is further subjected to the following treatment, that is, heating to a temperature at which the liquid crystal used obtains an isotropic phase, and then slowly cooling to room temperature, thereby removing the flow orientation when the liquid crystal is filled.

[0207] As the sealant, for example, epoxy resin containing alumina balls as spacers and a hardener can be used. As the spacer, a photoresist spacer, a bead spacer, or the like can be used.

[0208] As liquid crystal, any of positive and negative types can be used. In the case of using negative liquid crystal in IPS type and FFS type liquid crystal elements, the transmission loss on the upper part of the electrode can be reduced, and the contrast can be improved, which is preferred in this respect. In addition, as the liquid crystal used, nematic liquid crystal and smectic liquid crystal can be listed, among which nematic liquid crystal is preferred. As nematic liquid crystal, for example, Schiff base liquid crystal, azoxy liquid crystal, biphenyl liquid crystal, phenylcyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenylcyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane liquid crystal, cubane liquid crystal, etc. can be used. In addition, for example, cholesteric liquid crystal, chiral reagent, ferroelectric liquid crystal, etc. can be added to these liquid crystals for use.

[0209] In the PSA mode, the following treatment is performed: a polymerizable compound (e.g., a multifunctional (meth)acrylate compound, etc.) is filled into the cell gap together with a liquid crystal, and after constructing a liquid crystal cell, a voltage is applied between the conductive films of a pair of substrates, and the liquid crystal cell is irradiated with light. When manufacturing a liquid crystal element of the PSA mode, the polymerizable compound is used in a ratio of 0.01 to 3 parts by mass, preferably 0.1 to 1 part by mass, relative to a total of 100 parts by mass of the liquid crystal.

[0210] In addition, in the manufacturing process of the PSA mode liquid crystal element, in order to react the polymerizable compound in the liquid crystal, it is necessary to make the light exposure to the liquid crystal unit more, so there is a concern that the liquid crystal components will decompose due to such ultraviolet irradiation, causing a decrease in display quality. On the other hand, if the light exposure to the liquid crystal unit is reduced, the unreacted polymerizable compound remains in the film or in the liquid crystal. In the case where the unreacted polymer component remains in the film or in the liquid crystal as an impurity, there is a concern that the quality will be reduced due to the long-term exposure of the liquid crystal element to a high temperature environment. In this regard, it is believed that by using the liquid crystal alignment agent disclosed in the present invention to form a liquid crystal alignment film, the polymerizable compound in the liquid crystal can be efficiently reacted with a small amount of light exposure, and a high liquid crystal orientation restriction force can be exhibited, thereby showing a stable pretilt angle in the film region, and long-term heat resistance can be improved.

[0211] Then, a polarizing plate is attached to the outer surface of the liquid crystal cell as needed. Examples of the polarizing plate include a polarizing plate formed by sandwiching a polarizing film called "H film" by cellulose acetate protective films, or a polarizing plate containing the H film itself. The "H film" is formed by absorbing iodine while stretching and aligning polyvinyl alcohol. Thus, a liquid crystal cell is obtained.

[0212] The liquid crystal element disclosed in the present invention can be effectively applied to various purposes, such as clocks, portable game consoles, word processors, notebook personal computers, car navigation systems, cameras, personal digital assistants (PDAs), digital cameras, mobile phones, smart phones, various monitors, liquid crystal televisions, information displays and other display devices, or dimming films, etc. In addition, the liquid crystal element formed using the liquid crystal alignment agent disclosed in the present invention can also be applied to optical films such as phase difference films.

[0213] [Example]

[0214] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0215] <Measurement method>

[0216] In the following examples, the solution viscosity, weight average molecular weight (Mw) and imidization ratio of the polymer were measured by the following methods.

[0217] [Solution viscosity of polymer]

[0218] The solution viscosity of the polymer was measured at 25°C using an E-type viscometer.

[0219] [Weight average molecular weight of polymer (Mw)]

[0220] Mw was measured by gel permeation chromatography (GPC) under the following conditions.

[0221] Device: Showa Denko Co., Ltd.'s "GPC-101"

[0222] GPC column: Combination of GPC-KF-801, GPC-KF-802, GPC-KF-803 and GPC-KF-804 manufactured by Shimadzu GLC Co., Ltd.

[0223] Mobile phase: tetrahydrofuran (THF)

[0224] Column temperature: 40℃

[0225] Flow rate: 1.0mL / min

[0226] Sample concentration: 1.0 mass%

[0227] Sample injection volume: 100μL

[0228] Detector: Differential refractometer

[0229] Standard material: monodisperse polystyrene

[0230] [Imidization ratio of polyimide]

[0231] The polyimide solution was put into pure water, the obtained precipitate was fully dried under reduced pressure at room temperature, and then dissolved in deuterated dimethyl sulfoxide. The hydrogen nuclear magnetic resonance (HNMR) was performed at room temperature using tetramethylsilane as the reference substance. 1 H-NuclearMagnetic Resonance, 1 H-NMR) determination. 1 The imidization ratio [%] was determined from the H-NMR spectrum using the following formula (1).

[0232] Imidization rate [%] = (1-(β 1 / (β 2 ×α)))×100…(1)

[0233] (In formula (1), β 1 is the peak area of ​​the proton origin of the NH group appearing near the chemical shift of 10 ppm, β 2 is the peak area of ​​other proton sources, and α is the ratio of the number of other protons relative to one proton of the NH group in the precursor of the polymer (polyamic acid).

[0234] <Abbreviation of compound>

[0235] The abbreviations of the compounds used in the following examples are shown below. In addition, for convenience, the "compound represented by formula (X)" (X is a symbol) may be simply expressed as "compound (X)".

[0236] [Photoreactive monomer]

[0237] [Chemistry 19]

[0238]

[0239] [Vertical alignment monomer]

[0240] [Chemistry 20]

[0241]

[0242] [Chemistry 21]

[0243]

[0244] [Chemistry 22]

[0245]

[0246] [Chemistry 23]

[0247]

[0248] [Monomer containing a cyclic group]

[0249] [Chemistry 24]

[0250]

[0251] [Monomer containing reactive functional group]

[0252] [Chemistry 25]

[0253]

[0254] [Other monomers]

[0255] [Chemistry 26]

[0256]

[0257] [Tetracarboxylic dianhydride]

[0258] [Chemistry 27]

[0259]

[0260] [Diamine]

[0261] [Chemistry 28]

[0262]

[0263] [Chemistry 29]

[0264]

[0265] [Chemistry 30]

[0266]

[0267] [additive]

[0268] [Chemistry 31]

[0269]

[0270] <Synthesis of Compounds>

[0271] 1. Synthesis of liquid crystal alignment monomers

[0272] [Synthesis Example 1-1: Synthesis of Compound (M-01)]

[0273] [Chemistry 32]

[0274]

[0275] 3.05 g of 4-(chloromethyl)styrene, 4.93 g of 4-(4-pentylcyclohexyl)phenol, and 5.48 g of potassium carbonate were dissolved in 40 mL of dimethylformamide and reacted at 60° C. for 12 hours. After confirming the disappearance of the raw materials by high performance liquid chromatography (HPLC), the reaction solution was added dropwise to 400 mL of water and the generated solid was filtered out. Then, recrystallization was performed in a THF solvent, and the obtained solid was filtered out and dried to obtain 5.80 g of compound (M-01).

[0276] [Synthesis Example 1-2: Synthesis of Compound (M-02)]

[0277] [Chemistry 33]

[0278]

[0279] 2.46 g of 4-(4-pentylcyclohexyl)phenol, 12.5 g of 2-bromoethanol, and 16.6 g of potassium carbonate were dissolved in 200 mL of dimethylformamide and reacted at 100° C. for 5 hours. After the reaction, the reaction solution was poured into 1 L of water, and the generated solid was filtered and dried to obtain 28.1 g of compound (M-02-1).

[0280] Then, 26.1 g of compound (M-02-1) was dissolved in 200 ml of dichloromethane, and 10 mL of pyridine was added, and the mixture was cooled to 0°C. 100 mL of dichloromethane in which 17.2 g of tosyl chloride was dissolved was added dropwise, and the mixture was reacted at room temperature overnight. After the reaction, 200 mL of water was used for three liquid separations, and the organic layer was distilled to remove the solvent. The obtained solid was purified by column chromatography to obtain 17.2 g of compound (M-02-2).

[0281] Compound (M-02-2) 13.3g, 4-hydroxyphenylmaleimide 5.68g, triethylamine 3.33g were dissolved in tetrahydrofuran 200mL and reacted under reflux for 4 hours. After the reaction, ethyl acetate 200mL was added, and 1 equivalent hydrochloric acid 200mL was used for two liquid separations, and water 200mL was used for three liquid separations. The organic layer was distilled off the solvent under reduced pressure. The obtained solid was dissolved in THF 150mL, and ethanol 60mL and water 50mL were added thereto. The good solvent was slowly distilled off using a rotary evaporator, and the precipitated solid was filtered and dried to obtain 8.58g of compound (M-02).

[0282] [Synthesis Example 1-3: Synthesis of Compound (M-03)]

[0283] [Chemistry 34]

[0284]

[0285] To 2.74 g of 4-(4-pentylcyclohexyl)benzoic acid, 20 mL of thionyl chloride and a catalytic amount of dimethylformamide (DMF) were added, and the mixture was reacted at 60°C for 2 hours. After the reaction, thionyl chloride was removed by distillation under reduced pressure. The obtained solid was dissolved in 20 mL of dehydrated THF to prepare solution A. On the other hand, 1.90 g of 4-hydroxyphenylmaleimide and 1.20 g of triethylamine were dissolved in 20 mL of dehydrated THF and ice-cooled to 0°C. Solution A was added dropwise thereto, and the mixture was reacted at room temperature overnight. After the reaction, the reaction solution was separated twice with 1 N hydrochloric acid and three times with water. The organic layer was removed by distillation under reduced pressure. Furthermore, the obtained solid was dissolved in 50 mL of THF, and 30 mL of ethanol and 10 mL of water were added thereto. The good solvent was slowly distilled off using a rotary evaporator, and the precipitated solid was filtered out and dried to obtain 3.81 g of compound (M-03).

[0286] [Synthesis Example 1-4: Synthesis of Compound (M-04)]

[0287] In Synthesis Example 1-3, 9.25 g of compound (M-04) was obtained by the same method as Synthesis Example 1-3, except that 4'-pentyl-[1,1'-di(cyclohexane)]-4-carboxylic acid was used instead of 4-(4-pentylcyclohexyl)benzoic acid, and 4-(2-hydroxyethyl)phenylmaleimide was used instead of 4-hydroxyphenylmaleimide.

[0288] [Synthesis Example 1-5: Synthesis of Compound (M-05)]

[0289] In Synthesis Example 1-2, 12.1 g of a compound (M-05) was obtained by the same method as Synthesis Example 1-2, except that 4-hydroxystyrene was used instead of 4-hydroxyphenylmaleimide.

[0290] [Synthesis Example 1-6: Synthesis of Compound (M-06)]

[0291] In Synthesis Example 1-1, 8.08 g of a compound (M-06) was obtained by the same method as in Synthesis Example 1-1, except that β-cholesterol was used instead of 4-(4-pentylcyclohexyl)phenol.

[0292] [Synthesis Example 1-7: Synthesis of Compound (M-07)]

[0293] In Synthesis Example 1-2, 5.82 g of compound (M-07) was obtained by the same method as Synthesis Example 1-2, except that 4-(4'-pentyl-[1,1'-bicyclohexyl]-4-yl)phenol was used instead of 4-(4-pentylcyclohexyl)phenol, and 4-hydroxy-3-methylphenylmaleimide was used instead of 4-hydroxyphenylmaleimide.

[0294] [Synthesis Example 1-8: Synthesis of Compound (M-08)]

[0295] 7.11 g of compound (M-08) was obtained by the same method as in Synthesis Example 1-1 except that 4-(4′-pentyl-[1,1′-bicyclohexyl]-4-yl)phenol was used instead of 4-(4-pentylcyclohexyl)phenol.

[0296] [Synthesis Example 1-9: Synthesis of Compound (M-09)]

[0297] [Chemistry 35]

[0298]

[0299] In a 500mL three-necked flask equipped with a stirrer, add 4-(4-heptylcyclohexyl)phenol 10.0g, 1-(4-fluorophenethyl)-1H-pyrrole-2,5-dione 8.8g, potassium carbonate 5.6g, N,N-dimethylformamide 200mL, and stir at room temperature for 30 minutes. After confirming that the raw materials are dissolved, react at 80°C for 12 hours. After the reaction, the reaction solution is injected into 1500mL of distilled water and the precipitated solid is filtered out. Thereafter, the solid is vacuum dried and recrystallized to obtain 13.7g of compound (M-09). In addition, 1-(4-fluorophenethyl)-1H-pyrrole-2,5-dione was synthesized according to the method described in "Molecules", 2016, 21, 1198.

[0300] [Synthesis Example 1-10: Synthesis of Compound (M-10)]

[0301] In Synthesis Example 1-1, 4-(2-(4'-pentyl-[1,1'-bicyclohexyl]-4-yl)ethyl)phenol was used instead of 4-(4-pentylcyclohexyl)phenol, and 7.56 g of compound (M-10) was obtained by the same method as Synthesis Example 1-1. In addition, 4-(2-(4'-pentyl-[1,1'-bicyclohexyl]-4-yl)ethyl)phenol was synthesized according to the method described in Japanese Patent Laid-Open No. 2013-228672.

[0302] [Synthesis Example 1-11: Synthesis of Compound (M-11)]

[0303] In Synthesis Example 1-3, 6.49 g of compound (M-11) was obtained by the same method as Synthesis Example 1-3, except that 4-(4'-(4,4,4-trifluorobutyl)-[1,1'-bicyclohexane]-4-yl)benzoic acid was used instead of 4-(4-pentylcyclohexyl)benzoic acid, and 4-hydroxy-3-methylphenylmaleimide was used instead of 4-hydroxyphenylmaleimide.

[0304] [Synthesis Example 1-12: Synthesis of Compound (M-12)]

[0305] [Chemistry 36]

[0306]

[0307] In Synthesis Example 1-9, 12.1 g of a compound (M-12-1) was obtained by the same method as Synthesis Example 1-9, except that 1-fluoro-3-nitrobenzene was used instead of 1-(4-fluorophenethyl)-1H-pyrrole-2,5-dione.

[0308] Then, 12.0 g of compound (M-12-1), 1.94 g of 5% palladium carbon, 60 mL of tetrahydrofuran, and 60 mL of ethanol were added to a 500 mL three-necked flask equipped with a stirrer and heated to 80°C. 9.11 g of hydrazine hydrate monohydrate was added dropwise thereto, and the mixture was heated under reflux for 6 hours. After cooling to room temperature, the filtered solution was reprecipitated with 600 mL of water. The obtained solid was filtered, washed with water, and then vacuum dried to obtain 9.8 g of compound (M-12-2).

[0309] The compound (M-12-2) was taken out into a 500 mL three-necked flask equipped with a stirrer, 100 mL of tetrahydrofuran was added and an ice bath was performed. A solution containing 2.15 g of maleic anhydride and 50 mL of tetrahydrofuran was added dropwise thereto, and stirred at room temperature for 3 hours. Thereafter, the precipitated solid was recovered by filtration. The obtained solid was vacuum dried to obtain 9.5 g of compound (M-12).

[0310] [Synthesis Example 1-13: Synthesis of Compound (M-13)]

[0311] [Chemistry 37]

[0312]

[0313] In Synthesis Example 1-12, 4'-(4,4,4-trifluorobutyl)-[1,1'-bicyclohexane]-4-ol was used instead of 4-(4-heptylcyclohexyl)phenol, and 1-fluoro-4-nitrobenzene was used instead of 1-fluoro-3-nitrobenzene, and 11.1 g of compound (M-13-1) was obtained by the same method as compound (M-12-1). Then, 7.5 g of compound (M-13-2) was obtained by the same method as compound (M-12-2), except that compound (M-13-1) was used instead of compound (M-12-1).

[0314] In a 300mL eggplant-shaped flask equipped with a stirrer, 3.00g of monomethyl maleate, 15g of thionyl chloride, and 0.01g of N,N-dimethylformamide were added and stirred at 60°C for 2 hours. Thereafter, the excess thionyl chloride was removed by a diaphragm pump, and 30g of tetrahydrofuran was added to prepare solution A. In a 500mL three-necked flask equipped with a stirrer, 8.84g of compound (M-13-2), 100g of tetrahydrofuran, and 4.7g of triethylamine were newly added and ice-bathed. Solution A was added dropwise thereto and stirred at room temperature for 8 hours. The reaction solution was reprecipitated with 750mL of water, and the obtained white solid was vacuum dried to obtain 9.8g of compound (M-13).

[0315] [Synthesis Example 1-17: Synthesis of Compound (M-17)]

[0316] In Synthesis Example 1-1, 4.58 g of a compound (M-17) was obtained by the same method as Synthesis Example 1-1, except that 4-pentylcyclohexanol was used instead of 4-(4-pentylcyclohexyl)phenol.

[0317] [Synthesis Examples 1-14 to 1-16, 1-18, 1-19: Synthesis of Compounds (M-14 to M-16, M-18, M-19)]

[0318] Compounds (M-14 to M-16, M-18, and M-19) were synthesized according to the methods described in the following documents.

[0319] Compound (M-14): Japanese Patent Publication No. 2006-178149

[0320] Compound (M-15): Japanese Patent Publication No. 2004-2373

[0321] Compound (M-16): Japanese Patent Publication No. 2004-99446

[0322] Compound (M-18): Japanese Patent Publication No. 2008-191337

[0323] Compound (M-19): International Publication No. 2006 / 001096

[0324] [Synthesis Example 1-20: Synthesis of Compound (E-2)]

[0325] 4.76 g of compound (E-2) was obtained by the same method as in Synthesis Example 1-1 except that 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylacetophenone and sodium hydride were used instead of 4-(4-pentylcyclohexyl)phenol and potassium carbonate, respectively.

[0326] [Synthesis Example 1-21: Synthesis of Compound (E-3)]

[0327] 4.68 g of compound (E-3) was obtained by the same method as in Synthesis Example 1-2 except that 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylacetophenone was used instead of compound (M-02-1).

[0328] [Synthesis Example 1-22: Synthesis of Compound (E-4)]

[0329] [Chemistry 38]

[0330]

[0331] 7.93 g of 4-hydroxybenzophenone, 5.0 g of 2-bromoethanol, and 11.06 g of potassium carbonate were dissolved in 80 mL of dimethylformamide and reacted at 100° C. for 10 hours. After confirming the disappearance of the raw materials by HPLC, the reaction solution was added dropwise to 500 mL of water, and the generated solid was filtered and dried to obtain 9.21 g of intermediate (E-4-1).

[0332] Then, 2.42 g of the intermediate (E-4-1) was dissolved in 20 mL of dimethylformamide and stirred at 0°C. Thereafter, 0.60 g of sodium hydride (60%, paraffin dispersion) was added and stirred at 0°C for 30 minutes. Thereafter, 1.53 g of 4-(chloromethyl)styrene was added and the mixture was reacted at 0°C for 3 hours. After confirming the disappearance of the raw materials by HPLC, the reaction solution was added dropwise to 150 mL of water and separated and purified by ethyl acetate. The separated organic layer was distilled under reduced pressure to remove the solvent and dried to obtain 3.40 g of compound (E-4).

[0333] [Synthesis Example 1-23: Synthesis of Compound (E-5)]

[0334] In Synthesis Example 1-1, 4.50 g of compound (E-5) was obtained by the same method as Synthesis Example 1-1, except that 4′-hydroxyacetophenone was used instead of 4-(4-pentylcyclohexyl)phenol.

[0335] <Synthesis of polymer>

[0336] 1. Synthesis of polymer [P]

[0337] [Synthesis example 2-1]

[0338] Under nitrogen, 10 mol parts of compound (M-01), 10 mol parts of compound (E-2), 30 mol parts of compound (A-5), 10 mol parts of compound (A-6), 20 mol parts of compound (B-3), and 20 mol parts of compound (B-6), 2 mol parts of 2,2'-azobis(2,4-dimethylvaleronitrile) as a free radical polymerization initiator, and 50 ml of tetrahydrofuran as a solvent were added to a 100 mL two-necked flask, and polymerization was carried out at 70° C. for 6 hours. After reprecipitation in methanol, the precipitate was filtered and vacuum dried at room temperature for 8 hours to obtain a styrene-maleimide copolymer (referred to as polymer (P-1)). The weight average molecular weight Mw measured by GPC and converted to polystyrene was 92700, and the molecular weight distribution Mw / Mn was 4.78.

[0339] [Synthesis Example 2-2 to Synthesis Example 2-10, Synthesis Example 2-12 to Synthesis Example 2-24: Synthesis of polymer (P-2) to polymer (P-10), polymer (P-12), polymer (P-13), polymer (P-16) to polymer (P-19), polymer (P-20) to polymer (P-26)]

[0340] The types and amounts of monomers used in the polymerization were changed as described in the following Table 1. Except for this, the polymerization was carried out in the same manner as in Synthesis Example 2-1 to obtain polymers (P-2) to (P-10), polymer (P-12), polymer (P-13), polymer (P-16) to (P-19), and polymer (P-20) to (P-26), respectively.

[0341] [Synthesis Example 2-11: Synthesis of polymer (P-11)]

[0342] The type and amount of the monomers used in the polymerization were changed as described in the following Table 1. Except for this, polymerization was carried out in the same manner as in Synthesis Example 2-1 to obtain a solution containing a polymer (P-11-1). Subsequently, a compound represented by the following formula (MO-1) was added to the polymer solution in an amount of 1 mol relative to 2-hydroxyethyl methacrylate in the polymer, and the mixture was reacted at 50° C. for 6 hours to obtain a solution containing a polymer (P-11). After reprecipitation in methanol, the precipitate was filtered and vacuum dried at room temperature for 8 hours to obtain a polymer (P-11).

[0343] [Chemistry 39]

[0344]

[0345] [Comparative Synthesis Example 2-1 to Comparative Synthesis Example 2-3: Synthesis of Polymer (P-14), Polymer (P-15), and Polymer (P-27)]

[0346] Polymer (P-14), polymer (P-15), and polymer (P-27) were obtained in the same manner as in Synthesis Example 2-1 except that the types and amounts of monomers used in polymerization were changed as shown in Table 1 below.

[0347] [Table 1]

[0348]

[0349] 2. Synthesis of polymer [Q]

[0350] [Synthesis example 2-25]

[0351] 30 parts by mole of compound (DA-1) as a diamine, 50 parts by mole of compound (DA-8), and 20 parts by mole of compound (DA-9) were dissolved in N-methyl-2-pyrrolidone (NMP), 100 parts by mole of 2,3,5-tricarboxycyclopentylacetic dianhydride as a tetracarboxylic dianhydride was added, and the mixture was reacted at 40°C for 24 hours to obtain a solution containing 20% ​​by mass of polyamic acid. Subsequently, NMP was added to the obtained polyamic acid solution, and 1.80 molar equivalents of pyridine and acetic anhydride were added relative to the carboxyl groups of the acid dianhydride possessed by the polyamic acid, and a dehydration ring-closure reaction was carried out at 80°C for 4 hours. After the dehydration ring-closure reaction, the solvent in the system was replaced with a new NMP, and then concentrated to obtain a solution containing 20% ​​by mass of a polyimide (which was set as polymer (PI-1)) with an imidization rate of 70%. A small amount of this solution was taken and NMP was added to prepare a solution having a concentration of 10% by mass. The viscosity of this solution was measured to be 46.4 mPa·s.

[0352] [Synthesis Example 2-26, Synthesis Example 2-27, Synthesis Example 2-29 to Synthesis Example 2-36]

[0353] The types and amounts of tetracarboxylic dianhydride and diamine used in the polymerization were changed as described in Table 2. Except for this aspect, polymerization was carried out in the same manner as in Synthesis Example 2-18 to obtain solutions containing polymers (PI-2), polymers (PI-3), polymers (PI-5) to polymers (PI-12) as polyimides, respectively. In addition, the polymerization was carried out by adjusting the molar ratio of diamine to tetracarboxylic dianhydride (diamine / tetracarboxylic dianhydride) to 0.95 to 1.00 so that the viscosity of the NMP solution with a polymer concentration of 10% by mass was 40 mPa·s to 60 mPa·s. In Table 2, the numerical value of the anhydride represents the ratio (molar parts) of each compound relative to 100 molar parts of the total amount of tetracarboxylic dianhydride used in the synthesis. The numerical value of the diamine represents the ratio (molar parts) of each compound relative to 100 molar parts of the total amount of the diamine used in the synthesis.

[0354] [Synthesis example 2-28]

[0355] 30 mol parts of compound (DA-1) as a diamine, 50 mol parts of compound (DA-3), and 20 mol parts of compound (DA-8) were dissolved in N-methyl-2-pyrrolidone (NMP), 100 mol parts of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as a tetracarboxylic dianhydride was added, and the mixture was reacted at 40° C. for 24 hours to obtain a solution containing 20% ​​by mass of a polyamic acid (referred to as polymer (PI-4)).

[0356] [Table 2]

[0357]

[0358] <Manufacturing and evaluation of liquid crystal elements>

[0359] [Example 1: PSA type liquid crystal display element]

[0360] (1) Preparation of Liquid Crystal Alignment Agent (AL-1)

[0361] To the solution containing 100 parts by mass of the polymer (PI-1) obtained in Synthesis Example 2-25, 10 parts by mass of the polymer (P-1) obtained in Synthesis Example 2-1, and NMP and butyl cellosolve (BC) as solvents were added to prepare a solution having a solvent composition of NMP / BC = 50 / 50 (mass ratio) and a solid content concentration of 4.0% by mass. The solution was filtered using a filter having a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-1).

[0362] (2) Preparation of Liquid Crystal Composition

[0363] To 10 g of nematic liquid crystal (MLC-6608 manufactured by Merck), 5% by mass of a liquid crystal compound represented by the following formula (L1-1) and 0.3% by mass of a photopolymerizable compound represented by the following formula (L2-1) were added and mixed to obtain a liquid crystal composition LC1.

[0364] [Chemistry 40]

[0365]

[0366] (3) Manufacturing of PSA-type liquid crystal display elements

[0367] The liquid crystal alignment agent (AL-1) prepared in the above was applied to each electrode surface of two glass substrates having a conductive film including an ITO electrode patterned into a slit shape using a liquid crystal alignment film printer (manufactured by Nippon Shashin Printing Co., Ltd.), and heated (pre-baked) on a heating plate at 80°C for 2 minutes to remove the solvent, and then heated (post-baked) on a heating plate at 230°C for 30 minutes to form a coating with an average film thickness of 100 nm. For the coating, after ultrasonic cleaning in ultrapure water for 1 minute, it was dried in a clean oven at 100°C for 10 minutes to obtain a pair (two pieces) of substrates with a liquid crystal alignment film. In addition, the pattern of the electrode used is a pattern of the same type as the electrode pattern in the PSA mode.

[0368] Then, an epoxy resin adhesive containing alumina balls with a diameter of 5.5 μm is applied to the outer edge of the surface having a liquid crystal alignment film of one of the pair of substrates, and then the surfaces of the liquid crystal alignment films are overlapped and crimped so that the adhesive is cured. Then, the liquid crystal composition LC1 prepared above is filled between the pair of substrates from the liquid crystal injection port, and the liquid crystal injection port is sealed with an acrylic light-curing adhesive, thereby manufacturing a liquid crystal unit. Then, an alternating current of 10 V with a frequency of 60 Hz is applied between the conductive films of the liquid crystal unit, and an ultraviolet irradiation device using a metal halide lamp as a light source is used with a radiation intensity of 100,000 J / m 2 The ultraviolet rays are irradiated at an irradiation amount of . In addition, the irradiation amount is a value measured by a light meter based on a wavelength of 365 nm. Then, polarizing plates are attached to the outer sides of the substrate in such a manner that the polarization directions of the polarizing plates are orthogonal to each other and form an angle of 45° with the optical axis of the ultraviolet rays of the liquid crystal alignment film in the projection direction of the substrate surface, thereby manufacturing a PSA type liquid crystal display element.

[0369] (4) Evaluation of Liquid Crystal Orientation (Usually Film Thickness)

[0370] For the PSA type liquid crystal display element manufactured in the above (3), an optical microscope was used to observe whether there were abnormal domains in the change of light and dark when the voltage of 5V was turned on / off (applied / released), and the liquid crystal orientation was evaluated. When evaluating, the case with no abnormal domain and unevenness was set as "excellent (◎)", the case with no abnormal domain and unevenness in part was set as "good (○)", the case with abnormal domain in part was set as "acceptable (△)", and the case with abnormal domain as a whole was set as "poor (×)". As a result, in this example, the evaluation of liquid crystal orientation was "excellent (◎)".

[0371] (5) Evaluation of Liquid Crystal Orientation (Thin Film)

[0372] In the above (3), the average film thickness of the coating film was changed from 100 nm to 30 nm. Except for this, the PSA type liquid crystal display element was produced in the same manner as in the above (3). For the produced PSA type liquid crystal display element, the presence or absence of abnormal domains in the change of light and dark when the voltage of 5V was turned on / off (applied / released) was observed using an optical microscope, and the liquid crystal orientation was evaluated using the same 4-stage evaluation as in the above (4). As a result, in this example, the evaluation of the liquid crystal orientation when the film was made was "excellent (◎)".

[0373] 6. Evaluation of electrical characteristics using voltage holding ratio (VHR)

[0374] For the PSA type liquid crystal display element manufactured as described above, after applying a voltage of 5V with an application time of 60 microseconds and a span of 167 milliseconds, the voltage holding rate is measured 167 milliseconds after the application is released. The measuring device is VHR-1 manufactured by TOYO Technica (Co., Ltd.). At this time, when the voltage holding rate is 98% or more, it is set to "good (○)", when it is 95% or more and less than 98%, it is set to "acceptable (△)", and when it is less than 95%, it is set to "poor (×)". As a result, in this example, the evaluation of the electrical characteristics is "good (○)".

[0375] (7) Evaluation of long-term heat resistance

[0376] A PSA type liquid crystal unit is manufactured by performing the same operation as described in (3) except that polarizing plates are not attached to both outer surfaces of the substrate. For the PSA type liquid crystal unit, the same operation as described in (6) is performed to measure the voltage holding rate. In addition, after the obtained liquid crystal unit is stored in a constant temperature bath at 100°C for 21 days (about 500 hours), the voltage holding rate is measured again. When the decrease in the voltage holding rate caused by storage in a constant temperature bath at 100°C (voltage holding rate after liquid crystal unit manufacturing (%) - voltage holding rate after storage in the constant temperature bath (%)) is less than 20%, it is set to "good (○)", when it is more than 20% and less than 40%, it is set to "acceptable (△)", and when it is more than 40%, it is set to "poor (×)". The result is evaluated as "good (○)" in this example.

[0377] [Example 2 to Example 35 and Comparative Example 1 to Comparative Example 5]

[0378] The formulation composition was changed as shown in Table 3 and Table 4. Except for this, liquid crystal aligning agents (AL-2) to (AL-40) were prepared with the same solvent composition and solid content concentration as in Example 1. In addition, using each liquid crystal aligning agent, a PSA type liquid crystal display element was manufactured in the same manner as in Example 1, and various evaluations were performed. The evaluation results are shown in Table 3 and Table 4.

[0379] [Table 3]

[0380]

[0381] [Table 4]

[0382]

[0383] As shown in Table 3, in the liquid crystal alignment agents of Examples 1 to 18, the evaluations of liquid crystal orientation (usually film thickness, thin film), voltage holding ratio and long-term heat resistance are all "◎", "○" or "△", achieving a balance of various characteristics. In particular, in Examples 1 to 14 using a polymer containing a vertically oriented monomer unit having a group represented by the formula (8) as the polymer [P], the evaluation of the liquid crystal orientation of the thin film is excellent or good compared to Examples 15 to 18 using a polymer not containing a monomer unit having a group represented by the formula (8). It is believed that the reason is that by using a polymer [P] having a specific main chain structure having a partial structure A as a polymer component of the liquid crystal alignment agent, the photopolymerizable compound mixed into the liquid crystal layer reacts efficiently, which can improve the orientation fixation ability.

[0384] In addition, as shown in Table 4, the evaluations of the liquid crystal orientation (usually film thickness, thin film), voltage holding ratio and long-term heat resistance of the liquid crystal alignment agents of Examples 19 to 35 were all "◎" or "○", and a balance of various characteristics was achieved. In particular, when a polymer containing a vertical alignment monomer unit having two or more ring structures is used as the polymer [Q], there is a tendency to obtain excellent results in the evaluation of the liquid crystal orientation of the thin film.

[0385] In contrast, the liquid crystal alignment agents of Comparative Examples 1 to 3 that do not contain the polymer [P] disclosed herein show good liquid crystal alignment at a normal film thickness (0.1 μm), but when the thickness of the liquid crystal alignment film is thin, the orientation of the liquid crystal cannot be fully controlled, resulting in a poor result in the evaluation of the liquid crystal alignment of the film. In addition, the liquid crystal alignment agent of Comparative Example 4 has a poor result in the evaluation of the liquid crystal alignment of the film, and the liquid crystal alignment agent of Comparative Example 5 has a poor result in the evaluation of the liquid crystal alignment of both the normal film thickness and the film.

Claims

1. A liquid crystal alignment agent, comprising a polymer [P], wherein the polymer [P] is an addition polymer having a partial structure A or a polymerizable carbon-carbon unsaturated bond in a polymer side chain, The polymer [P] has at least one selected from the group consisting of a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula (4), In formula (1), R 1 and R 2 are each independently a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom, or R 1 and R 2 Bonded to each other and to R 1 and R 2 The carbon atoms bonded together form a ring structure; X 1 A monovalent group having a partial structure A or having a polymerizable carbon-carbon unsaturated bond; R 3 is a monovalent substituent; m1 is an integer from 0 to 4; n1 is an integer from 0 to 2; when m1 is 2 or more, multiple R 3 The same or different from each other; "*" indicates a bonding bond; In formula (2), R 4 and R 5 are each independently a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom, or R 4 and R 5 Bonded to each other and to R 4 and R 5 The carbon atoms bonded together form a ring structure; R 6 is a hydrogen atom or a monovalent organic group; X 2 A monovalent group having a partial structure A or having a polymerizable carbon-carbon unsaturated bond; R 7 is a monovalent substituent; m2 is an integer from 0 to 4; n2 is an integer from 0 to 2; when m2 is 2 or more, multiple R 7 The same or different from each other; "*" indicates a bonding bond; In formula (3), R 8 X is a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom; 3 A monovalent group having a partial structure A or having a polymerizable carbon-carbon unsaturated bond; R 9 is a monovalent substituent; m3 is an integer of 0 to 4; when m3 is 2 or more, multiple R 9 The same or different from each other; "*" indicates a bonding bond; In formula (4), R 10 Z is a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom; 1 is an oxygen atom or -NH-; X 4 A monovalent group having a partial structure A or having a polymerizable carbon-carbon unsaturated bond; "*" indicates a bonding bond; When X 1 , X 2 , X 3 and X 4 When X is a group having the partial structure A, 1 , X 2 , X 3 and X 4 is a group represented by the following formula (a-1) or a group represented by the following formula (a-2); In formula (a-1), Ar 1 and Ar 2 Ar 1 is a divalent aromatic ring group and Ar 2 is an alkyl group or a monovalent aromatic ring group, or Ar 1 and Ar 2 Combined with Ar 1 and Ar 2 The carbonyl group to which it is bonded together forms a ring structure; R 31 It is a single bond or a divalent organic group; "*" indicates a bonding bond; In formula (a-2), Ar 3 is a divalent aromatic ring group; R 32 and R 33 are independently a monovalent organic group, or represent R 32 and R 33 Combined with R 32 and R 33 The carbon atoms bonded together form a ring structure; R 34 is a hydroxyl group or a monovalent organic group; R 35 It is a single bond or a divalent organic group; "*" indicates a bonding bond; When X 1 , X 2 , X 3 and X 4 When X is a monovalent group having a polymerizable carbon-carbon unsaturated bond, 1 , X 2 , X 3 and X 4 , is a group represented by the following formula (a-3), *-R 37 -D 1 …(a-3) In formula (a-3), D 1 is (meth)acryloyl, vinyl, vinylphenyl or vinyl ether, R 37 is a single bond or a divalent organic group, In the formula (a-3), R 37 In the above, the divalent organic group is a divalent hydrocarbon group having 1 to 20 carbon atoms, or any methylene group possessed by the hydrocarbon group is substituted by -O-, -S- or -NR 36 -substituted group having 2 to 20 carbon atoms, or a group having 2 to 20 carbon atoms in which any hydrogen atom possessed by a hydrocarbon group is substituted with a fluorine atom, an alkoxy group or a hydroxy group.

2. The liquid crystal alignment agent according to claim 1, wherein The polymer [P] or a polymer different from the polymer [P] includes a polymer having at least any one of the following (a) and (b): The above (a) is a group represented by the following formula (8), A 1 -B 1 -L 1 -B 2 -L 2 -*…(8) In formula (8), A 1 is a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a fluoroalkyl group having 1 to 20 carbon atoms, or a fluoroalkoxy group having 1 to 20 carbon atoms; B 1 is a divalent group represented by any one of the following formulas (1-1) to (1-8); L 1 is a single bond or a divalent group represented by any one of the following formulae (2-1) to (2-6); B 2 is a single bond or a divalent aromatic ring group; L 2 is a divalent group represented by any one of the following formulae (3-1) to (3-9); "*" represents a bonding bond, (b) a non-photosensitive monovalent group having an alkyl group, an alkoxy group, a fluoroalkyl group or a fluoroalkoxy group having 5 or more carbon atoms, excluding the group corresponding to the above (a).

3. The liquid crystal alignment agent according to claim 2, wherein: The polymer [P] is a polymer having the (a) non-photosensitive monovalent group and comprises at least one selected from the group consisting of a structural unit represented by the following formula (5), a structural unit represented by the following formula (6), and a structural unit represented by the following formula (7), In formula (5), R 11 and R 12 are each independently a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom, or R 11 and R 12 Bonded to each other and to R 11 and R 12 The carbon atoms bonded together form a ring structure; Y 1 is a non-photosensitive monovalent group having at least one of two aromatic rings and aliphatic rings in total; R 13 is a monovalent substituent; m4 is an integer of 0 to 4; n3 is an integer of 0 to 2; when m4 is 2 or more, multiple R 13 The same or different from each other; "*" indicates a bonding bond; In formula (6), R 14 and R 15 are each independently a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom, or R 14 and R 15 Bonded to each other and to R 14 and R 15 The carbon atoms bonded together form a ring structure; R 16 is a hydrogen atom or a monovalent organic group; Y 2 is a non-photosensitive monovalent group having at least one of two aromatic rings and aliphatic rings in total; R 17 is a monovalent substituent; m5 is an integer from 0 to 4; n4 is an integer from 0 to 2; when m5 is 2 or more, multiple R 17 The same or different from each other; "*" indicates a bonding bond; In formula (7), R 18 Y is a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent group having 1 to 10 carbon atoms in which any hydrogen atom of a hydrocarbon group is replaced by a halogen atom; 3 is a non-photosensitive monovalent group having at least one of two aromatic rings and aliphatic rings in total; R 19 is a monovalent substituent; m6 is an integer from 0 to 4; when m6 is 2 or more, multiple R 19 The same or different from each other; "*" indicates a bonding bond. 4 . The liquid crystal aligning agent according to claim 1 , further comprising a polymer [Q] different from the polymer [P].

5. The liquid crystal aligning agent according to claim 2, further comprising a polymer [Q] different from the polymer [P], The polymer [Q] has at least one of the (a) non-photosensitive monovalent group and the (b) non-photosensitive monovalent group.

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

7. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein The polymer [P] has at least one selected from the group consisting of a cyclic ether group and a cyclic carbonate group.

8. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein The polymer [P] has at least one selected from the group consisting of a carboxyl group, a protected carboxyl group, an amino group, and a protected amino group. 9 . A liquid crystal alignment film formed using the liquid crystal alignment agent according to claim 1 . 10 . A liquid crystal element comprising the liquid crystal alignment film according to claim 9 .

11. A method for manufacturing a liquid crystal element, comprising: A step of applying the liquid crystal alignment agent according to any one of claims 1 to 8 on each conductive film in a pair of substrates having a conductive film to form a coating film; A step of arranging a pair of substrates on which the coating film is formed so as to face each other with the coating film interposed therebetween to construct a liquid crystal cell; as well as and irradiating the liquid crystal cell with light while a voltage is applied between the conductive films.

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