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

Abstract

The invention provides a liquid crystal aligning agent which can obtain a liquid crystal element with excellent brightness characteristics and liquid crystal aligning property and can form a weak anchoring liquid crystal alignment film with excellent sealing property. The liquid crystal aligning agent contains a polymer (P) containing a structural unit (A) represented by formula (1), the content ratio of the structural unit (A) relative to all the structural units of the polymer (P) is 35% by mass or more, the polymer (P) has a specific crosslinkable group, and the liquid crystal aligning agent satisfies at least any one of requirements (I), (II) and (III). # imgabs0 #

Description

Technical Field

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

[0002] In a liquid crystal element, the initial alignment of liquid crystal molecules is generally defined by the anchoring of the liquid crystal molecules by a liquid crystal alignment film. In recent years, in liquid crystal elements of a horizontal alignment mode such as an In-Plane Switching (IPS) type or a Fringe Field Switching (FFS) type, various liquid crystal elements have been proposed: a liquid crystal alignment film having a strong anchoring energy is formed on one of a pair of substrates (hereinafter, also referred to as a "strongly anchored liquid crystal alignment film"), and a liquid crystal alignment film having no anchoring energy or a very small anchoring energy is formed on the other substrate (hereinafter, also referred to as a "weakly anchored liquid crystal alignment film"). In a liquid crystal element using a weakly anchored state, an improvement in brightness and contrast ratio, low voltage driving, high-speed response (high-speed rise), etc. can be achieved as compared with a normal liquid crystal element in which strongly anchored liquid crystal alignment films are formed on two substrates. In addition, "weak anchoring" is also referred to as "zero surface anchoring".

[0003] For example, Patent Document 1 discloses the following: A liquid crystal cell is manufactured by the following method: a zero surface anchoring film is formed on a first substrate, and a liquid crystal alignment film is formed on a second substrate using a known liquid crystal aligning agent, and the first method includes the following steps: energy sufficient to cause a polymerization reaction of a radically polymerizable compound is provided in a state where a liquid crystal composition containing a liquid crystal and a radically polymerizable compound is in contact with a radical generating film.

[0004] [Prior Art Documents]

[0005] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2019 / 004433 Summary of the Invention

[0007] [Problems to be Solved by the Invention]

[0008] In the technique described in Patent Document 1, when manufacturing a weakly anchored liquid crystal alignment film, the following steps are required: a liquid crystal composition containing a liquid crystal and a radically polymerizable compound is brought into contact with a radical generating film formed on a first substrate, and energy sufficient to cause a polymerization reaction of the radically polymerizable compound is provided in this state. From the viewpoint of productivity, it is desired to be able to manufacture a weakly anchored liquid crystal alignment film by a simple operation, and at the same time, an improved effect of brightness characteristics derived from the weakly anchored state can be obtained, and a liquid crystal element having good liquid crystal alignment property can be produced.

[0009] For example, in addition to mobile applications represented by smartphones or tablet personal computers (PCs), in large TVs or PC monitors, narrow bezels are achieved from the viewpoints of design or miniaturization of display devices. As one method for achieving narrow bezels, there is known a method in which a liquid crystal alignment film is formed over the entire substrate surface and then a sealant is applied to the liquid crystal alignment film to bond the substrates to each other. On the other hand, if the sealant is disposed on the liquid crystal alignment film, there is a concern that the adhesion between the substrates may be easily reduced and the substrates may be easily peeled off due to the action of external force or the like.

[0010] The present invention has been made in view of the above problems, and a main object thereof is to provide a liquid crystal aligning agent capable of obtaining a liquid crystal element excellent in brightness characteristics and liquid crystal alignment properties and capable of forming a liquid crystal alignment film excellent in adhesion.

[0011] [Means for Solving the Problems]

[0012] According to the present invention, the following means are provided.

[0013] [1] A liquid crystal aligning agent containing a polymer (P) including a structural unit (A) represented by the following formula (1):

[0014] [Chemical Formula 1]

[0015]

[0016] (In formula (1), a is an integer of 1 or more. R 1 is a hydrogen atom or a monovalent organic group. R 3 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms. X 1 is -O-, -S-, * 1 -C(=O)-O- or * 1 -O-C(=O)-. "* 1 " represents a bonding bond with R 2 . Among them, when R 3 is a hydrogen atom, X 3 bonded to R 1 is -O-, -S- or * 1 -C(=O)-O-. When a is 1 and R 3 is a hydrogen atom, or a is 1, R 1 is a monovalent organic group and R 3 is a methyl group, or a is 2, R 1 is a monovalent organic group and R 3 is a hydrogen atom, R 2is an alkanediyl group having 4 to 16 carbon atoms, and in other cases, is an alkanediyl group having 2 to 8 carbon atoms. Among them, R bonded to *-COO- (where "*" represents a bonding bond with a carbon atom constituting the main chain) in formula (1) 2 In adjacent X 1 When it is -O-, two oxygen atoms are connected via two or more carbon atoms. When a is 2 or more, multiple Rs 2 are the same or different, and multiple Xs 1 are the same or different),

[0017] With respect to all structural units of the polymer (P), the content ratio of the structural unit (A) is 35% by mass or more. The polymer (P) has at least one crosslinkable group selected from the group consisting of a hydroxyl group, a protected hydroxyl group, a protected amino group, a thiol group, a protected thiol group, a carboxyl group, a protected carboxyl group, an acid anhydride group, an oxiranyl group, a protected oxiranyl group, an oxetanyl group, and a protected isocyanate group, and the liquid crystal aligning agent satisfies at least any one of the following requirements (I), (II), and (III).

[0018] Requirement (I): The polymer (P) has a first functional group and a second functional group. The first functional group is any one of the crosslinkable groups, and the second functional group is a functional group that can react with the first functional group to form a bond among the crosslinkable groups or functional groups different from the crosslinkable groups, and is different from the first functional group.

[0019] Requirement (II): The polymer (P) has a self-crosslinkable functional group as the crosslinkable group.

[0020] Requirement (III): It further contains a compound (D), and the compound (D) is a compound having two or more functional groups that can react with the crosslinkable groups possessed by the polymer (P) to form a bond, and is different from the polymer (P).

[0021] [2] A weak-anchoring liquid crystal alignment film formed by using the liquid crystal aligning agent according to [1].[[]END]]

[0022] [3] A liquid crystal element including the weak-anchoring liquid crystal alignment film according to [2].[[]END]]

[0023] [Effects of the Invention]

[0024] According to the liquid crystal aligning agent of the present invention, a liquid crystal element having excellent brightness characteristics and liquid crystal alignment properties can be obtained. In addition, according to the liquid crystal aligning agent of the present invention, a liquid crystal alignment film having excellent adhesion can be formed. Description of the Drawings

[0025] Figure 1It is a schematic structural diagram of a FFS type liquid crystal display element.

[0026] Figure 2 (a) of Figure 2 (b) of is a plan view of the top electrode for manufacturing a liquid crystal display element. Figure 2 (a) of is a top view of the top electrode, Figure 2 (b) of is a partial enlarged view of the top electrode.

[0027] Figure 3 It is a diagram showing four systems of driving electrodes.

[0028] [Description of symbols]

[0029] 10: FFS type liquid crystal display element

[0030] 11a, 11b: Glass substrates

[0031] 12: Liquid crystal alignment film

[0032] 13: Top electrode

[0033] 14: Insulating layer

[0034] 15: Bottom electrode

[0035] 16: Liquid crystal layer

[0036] C1: Portion surrounded by a dotted line

[0037] d1: Line width of the electrode

[0038] d2: Distance between electrodes Detailed implementation mode

[0039] Hereinafter, matters related to the embodiment will be described in detail. In addition, in this specification, the numerical range described using "~" means that the numerical values described before and after "~" are included as the lower limit value and the upper limit value. The so-called "structural unit" is a unit that mainly constitutes the main chain structure, and means a unit that includes two or more units at least in the main chain structure. The structural unit is typically a repeating unit formed based on one monomer.

[0040] In this specification, the term "hydrocarbyl group" means a group including an acyclic hydrocarbyl group, an alicyclic hydrocarbyl group, and an aromatic hydrocarbyl group. The term "acyclic hydrocarbyl group" means a straight-chain or branched acyclic hydrocarbyl group in which the main chain does not contain a cyclic structure but only an acyclic structure. Among them, the acyclic hydrocarbyl group may be saturated or unsaturated. The term "alicyclic hydrocarbyl group" means a hydrocarbyl group in which the ring structure contains only an alicyclic hydrocarbon structure and does not contain an aromatic ring structure. Among them, the alicyclic hydrocarbyl group does not need to include only the structure of an alicyclic hydrocarbon, and also includes a group having an acyclic structure in a part thereof. The term "aromatic hydrocarbyl group" means a hydrocarbyl group containing an aromatic ring structure as the ring structure. Among them, the aromatic hydrocarbyl group does not need to include only the aromatic ring structure, and may also include an acyclic structure or an alicyclic hydrocarbon structure in a part thereof. The term "organic group" means an atomic group obtained by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound).

[0041] The "main chain" of a polymer means the "backbone" part of the polymer that contains the longest chain of atoms. The "backbone" part is allowed to contain a cyclic structure. For example, the phrase "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. The "side chain" means a part branched from the "backbone" part of the polymer. The term "(meth)acrylic group" is a term including an acrylic group and a methacrylic group, and the term "(meth)acryloyl" is a term including an acryloyl and a methacryloyl. The term "(meth)acrylate" is a term including an acrylate and a methacrylate.

[0042] "Liquid Crystal Alignment Agent"

[0043] The liquid crystal alignment agent of the present disclosure contains a polymer (P) including a structural unit (A) represented by the following formula (1).

[0044] [Chemical Formula 2]

[0045]

[0046] (In formula (1), a is an integer of 1 or more. R 1 is a hydrogen atom or a monovalent organic group. R 3 is a hydrogen atom or a monovalent hydrocarbyl group having 1 to 6 carbon atoms. X 1 is -O-, -S-, * 1 -C(=O)-O- or * 1 -O-C(=O)-. "* 1 " represents a bonding bond with R 2 . Among them, when R 3 is a hydrogen atom, X 3 bonded to R 1 is -O-, -S- or * 1 -C(=O)-O-. When a is 1 and R 3is a hydrogen atom, or a is 1, R 1 is a monovalent organic group and R 3 is a methyl group, or a is 2, R 1 is a monovalent organic group and R 3 is a hydrogen atom, R 2 is an alkanediyl group having 4 to 16 carbon atoms, and in other cases is an alkanediyl group having 2 to 8 carbon atoms. Among them, R 2 to which *-COO- (where "*" represents a bonding bond to a carbon atom constituting the main chain) in formula (1) is bonded 1 When adjacent X 2 is -O-, two oxygen atoms are connected via two or more carbon atoms. When a is 2 or more, multiple R 1 are the same or different, and multiple X

[0047] The polymer (P) has at least one crosslinkable group selected from the group consisting of a hydroxyl group, a protected hydroxyl group, a protected amino group, a thiol group, a protected thiol group, a carboxyl group, a protected carboxyl group, an acid anhydride group, an oxiranyl group, a protected oxiranyl group, an oxetanyl group, and a protected isocyanate group (hereinafter, also referred to as "crosslinkable group R c "). According to the liquid crystal aligning agent of the present disclosure, by utilizing the reaction of the crosslinkable group R c possessed by the polymer (P), a liquid crystal alignment film having excellent adhesion to a sealant or a substrate while exhibiting weak anchoring characteristics can be formed.

[0048] Specifically, the liquid crystal aligning agent of the present disclosure is a polymer composition that satisfies at least any one of the following requirements (I), (II), and (III).

[0049] Requirement (I): The polymer (P) has a first functional group and a second functional group. The first functional group is any one of the crosslinkable groups R c , and the second functional group is a functional group capable of reacting with the first functional group to form a bond and is different from the first functional group. The second functional group may be the crosslinkable group R c , or may be a functional group different from the crosslinkable group R c .

[0050] Requirement (II): The polymer (P) has a self-crosslinkable functional group as the crosslinkable group R c .

[0051] Requirement (III): It further contains a compound (D), and the compound (D) is a compound having two or more functional groups capable of reacting with the crosslinkable group R c possessed by the polymer (P) to form a bond and is different from the polymer (P).

[0052] As specific embodiments of the liquid crystal aligning agent that satisfies at least any one of the above-mentioned requirements (I) to (III), for example, the following embodiments 1 to 4 can be cited.

[0053] (Embodiment 1) A polymer containing a structural unit (A) and having a first functional group and a second functional group in the same molecule (hereinafter, also referred to as "polymer (P1)").

[0054] (Embodiment 2) A first polymer and a second polymer different from the first polymer, both of which are polymers having a structural unit (A). The first polymer has a first functional group, and the second polymer has a second functional group. One of the first polymer and the second polymer may be the polymer (P1). In addition, the second polymer may or may not have a structural unit (A).

[0055] (Embodiment 3) A polymer containing a structural unit (A) and having a self-crosslinkable functional group (hereinafter, also referred to as "polymer (P2)").

[0056] (Embodiment 4) A polymer containing a structural unit (A) and having a crosslinkable group R c (hereinafter, also referred to as "polymer (P3)"), and a compound (D).

[0057] In addition, the liquid crystal aligning agents of the above-mentioned embodiments 1 to 4 may each contain other components other than those described above. For example, the liquid crystal aligning agents of the above-mentioned embodiments 1 to 3 may further contain a compound (D). In addition, as long as the liquid crystal aligning agent of the above-mentioned embodiment 1 contains the polymer (P1), it may further contain a polymer different from the polymer (P1).

[0058] Hereinafter, each component contained in the liquid crystal aligning agent of the present disclosure and other components optionally blended as needed will be described. In addition, regarding each component, unless otherwise specified, one kind may be used alone, or two or more kinds may be used in combination.

[0059] <Polymer (P)>

[0060] ·Structural unit (A)

[0061] In the above formula (1), as the monovalent organic group represented by R 1 , an alkyl group having 1 to 5 carbon atoms, a fluoroalkyl group having 1 to 5 carbon atoms, etc. can be cited. From the viewpoints of copolymerizability when synthesizing the polymer (P) or obtaining a liquid crystal element showing more excellent liquid crystal alignment properties, R 1 is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0062] When R 3 is a monovalent hydrocarbon group having 1 to 6 carbon atoms, as R3 , examples include: a monovalent chain hydrocarbon group, a monovalent alicyclic hydrocarbon group, and a monovalent aromatic hydrocarbon group. From the viewpoint of making the liquid crystal alignment property of the liquid crystal element more excellent, R 3 is preferably an alkyl group, more preferably a linear alkyl group.

[0063] In addition, when R 3 is a hydrogen atom and X 3 bonded to R 1 is -O-, -S- or * 1 -C(=O)-O-, the structural unit (A) has a hydroxyl group, a thiol group or a carboxyl group. These functional groups (hydroxyl group, thiol group, carboxyl group) are one form of the crosslinkable group R c possessed by the polymer (P).

[0064] R 2 The alkanediyl represented by may be linear or branched. When a is 1 and R 3 is a hydrogen atom, the carbon number of R 2 is preferably 4 to 12, more preferably 4 to 10. When the conditions of a being 1 and R 3 being a hydrogen atom are not satisfied, the carbon number of R 2 is preferably 2 to 6. From the viewpoint of making the weak anchoring property good, in the case of satisfying (1) a is 1 and R 3 is a hydrogen atom; (2) a is 1, R 1 is a monovalent organic group and R 3 is a methyl group; (3) a is 2, R 1 is a monovalent organic group and R 3 is a hydrogen atom, in any of these cases, R 2 is an alkanediyl having 4 to 16 carbon atoms, and in other cases, it is an alkanediyl having 2 to 8 carbon atoms. In addition, R 2 bonded to *-COO- (wherein, "*" represents a bonding bond with the carbon atom constituting the main chain) in the formula (1) connects two oxygen atoms via two or more carbon atoms in the case where the adjacent X 1 is -O-. In the above case, R 2 bonded to *-COO- in the formula (1) is preferably a linear alkanediyl.

[0065] From the viewpoints of the weak anchoring property and the adhesion of the film, a is preferably 1 to 30, more preferably 1 to 20, and still more preferably 1 to 15.

[0066] As specific examples of the monomer that provides the structural unit (A), compounds represented by the following formulas (a-1) to (a-26) can be cited.

[0067] [Chemical formula 3]

[0068]

[0069] [Chemical Formula 4]

[0070]

[0071] The content ratio of the structural unit (A) in the polymer (P) is 35% by mass or more with respect to all the structural units of the polymer (P). If the content ratio of the structural unit (A) is less than 35% by mass, the weak anchoring property cannot be sufficiently exhibited, and the improvement effects of the brightness property and the liquid crystal alignment property cannot be sufficiently obtained. From the viewpoint of well-balancedly exhibiting the liquid crystal alignment property and the adhesion property, the content ratio of the structural unit (A) is preferably 37% by mass or more, more preferably 40% by mass or more, further preferably 50% by mass or more, and still more preferably 60% by mass or more with respect to all the structural units of the polymer (P).

[0072] · Crosslinkable group

[0073] Crosslinkable group R c is a functional group that exhibits a thermal crosslinking reactivity. As the crosslinkable group R c for the protected hydroxyl group, protected amino group, protected thiol group, and protected carboxyl group in it, groups in which the hydrogen atom bonded to the heteroatom in the hydroxyl group, amino group, thiol group, and carboxyl group is replaced by a thermally dissociable group can be respectively exemplified.

[0074] As specific examples of the thermally dissociable group bonded to the oxygen atom in the protected hydroxyl group and the thermally dissociable group bonded to the sulfur atom in the protected thiol group, the following can be cited: tertiary alkyl groups (e.g., tert-butyl group, 1-methylcyclopentyl group, 1-methylcyclohexyl group, etc.), monovalent alicyclic saturated hydrocarbon groups having 3 to 12 carbon atoms, benzyl group, p-methoxybenzyl group, etc., which are ether-based thermally dissociable groups; alkoxyalkyl groups having 2 to 6 carbon atoms, 2-tetrahydrofuranyl group, 2-tetrahydropyranyl group (THP group), 2-methoxy-6-tetrahydropyranyl group, 2-methoxy-4-methyl-6-tetrahydropyranyl group, 4-methoxy-4-tetrahydropyranyl group, etc., which are acetal-based thermally dissociable groups; acyl-based thermally dissociable groups such as acetyl group and benzoyl group; allyl-based thermally dissociable groups such as allyl group and methallyl group; silyl ether-based thermally dissociable groups such as trimethylsilyl group, triethylsilyl group, and tert-butyldimethylsilyl group.

[0075] Specific examples of the thermally detachable group bonded to the nitrogen atom in the protected amino group include: urethane-based thermally detachable groups, amide-based thermally detachable groups, imide-based thermally detachable groups, sulfonamide-based thermally detachable groups, and the like. Among these, in terms of high thermal detachability, urethane-based thermally detachable groups are preferred. Specific examples thereof include: tert-butoxycarbonyl (Boc group), benzyloxycarbonyl, 1,1-dimethyl-2-haloethyloxycarbonyl, allyloxycarbonyl, 2-(trimethylsilyl)ethyloxycarbonyl, 9-fluorenylmethyloxycarbonyl, and the like.

[0076] Specific examples of the thermally detachable group bonded to the oxygen atom in the protected carboxyl group include the above-mentioned tertiary alkyl groups, acetal-based thermally detachable groups, and the like.

[0077] Specific examples of the protected oxiranyl group include 1,3-dioxolan-2-one-4-yl.

[0078] Specific examples of the protected isocyanate group include a group in which the isocyanate group is protected by a protecting agent such as 3,6-dimethylpyrazole, methyl ethyl ketone oxime, diethyl malonate, or ε-caprolactam. In addition, when the isocyanate group is protected with 3,6-dimethylpyrazole or methyl ethyl ketone oxime, the group derived from 3,6-dimethylpyrazole or methyl ethyl ketone oxime (i.e., the protecting group) detaches due to heat, and the isocyanate group is regenerated to carry out a crosslinking reaction. On the other hand, when the isocyanate group is protected with diethyl malonate, the group derived from diethyl malonate (the protecting group) does not detach, and a crosslinking reaction is carried out through a transesterification reaction.

[0079] Crosslinkable group R c It can be self-crosslinkable or co-reactive. As the crosslinkable group R c Specific examples in the case of a functional group that is self-crosslinkable include a protected isocyanate group. In the crosslinkable group R c When it is co-reactive, the liquid crystal aligning agent of the present disclosure may also contain a polymer having a functional group (i.e., a second functional group) capable of reacting with the crosslinkable group R c as the polymer (P). In addition, the liquid crystal aligning agent satisfying the above-mentioned requirement (I) or requirement (II) contains a polymer having a functional group capable of reacting with the crosslinkable group R c as the polymer (P).

[0080] · First functional group and second functional group

[0081] The functional group (second functional group) capable of reacting with the crosslinkable group R c As long as it is a group different from the first functional group, it can be a group selected from the crosslinkable group R c or a group different from the crosslinkable group R cDifferent groups. Specific examples of the second functional group include, when the first functional group is a hydroxyl group or a protected hydroxyl group, a carboxyl group, a protected carboxyl group, an acid anhydride group, an oxiranyl group, a protected oxiranyl group, an oxetanyl group, a protected isocyanate group, etc.

[0082] Functional groups capable of reacting with a protected amino group, a thiol group or a protected thiol group include a carboxyl group, a protected carboxyl group, an acid anhydride group, an oxiranyl group, a protected oxiranyl group, an oxetanyl group, a protected isocyanate group, a maleimide group, etc.

[0083] Functional groups capable of reacting with a carboxyl group, a protected carboxyl group or an acid anhydride group include a hydroxyl group, a protected hydroxyl group, a thiol group, a protected thiol group, a protected amino group, an oxiranyl group, a protected oxiranyl group, an oxetanyl group, a protected isocyanate group, an oxazolinyl group, etc.

[0084] Functional groups capable of reacting with an oxiranyl group, a protected oxiranyl group or an oxetanyl group include a hydroxyl group, a protected hydroxyl group, a thiol group, a protected thiol group, a protected amino group, a carboxyl group, a protected carboxyl group, an acid anhydride group, a protected isocyanate group, an oxazolinyl group, etc.

[0085] Functional groups capable of reacting with a protected isocyanate group include a hydroxyl group, a protected hydroxyl group, a thiol group, a protected thiol group, a protected amino group, a carboxyl group, a protected carboxyl group, an acid anhydride group, an oxiranyl group, a protected oxiranyl group, an oxetanyl group, etc. In addition, a polymer having a structural unit (A), having a protected isocyanate group as the first functional group, and further having a second functional group is a liquid crystal aligning agent that satisfies the requirements (I) and (II). Regarding the crosslinking reaction, refer to the non-patent literature "Ratna, Debdatta. 'Recent advances and applications of thermoset resins.' (2022).".

[0086] From the viewpoint of storage stability, the combination of the first functional group and the second functional group possessed by the polymer (P) is preferably a combination of an oxiranyl group and a protected carboxyl group, a combination of an oxiranyl group and a protected amino group, or a combination of a hydroxyl group and a protected isocyanate group. In addition, from the viewpoint of low-temperature curability, a combination of an oxiranyl group and a carboxyl group, or a combination of a hydroxyl group and a protected isocyanate group is preferred.

[0087] The polymer (P) may have a crosslinkable group R in the main chain of the polymer c or may have a crosslinkable group R in the side chainc In addition, the polymer (P) may also have a crosslinkable group R at the end of the polymer. c In terms of forming a liquid crystal alignment film showing good weak anchoring properties and making the liquid crystal alignment property and the adhesion of the liquid crystal alignment film of the liquid crystal element more excellent, the polymer (P) is preferably a polymer containing a crosslinkable group R. c of the structural unit.

[0088] When the polymer (P) contains a structural unit having a crosslinkable group R c The crosslinkable group R c may be possessed by the structural unit (A), or may be possessed by a structural unit different from the structural unit (A) (hereinafter, also referred to as "structural unit (B)"). In addition, the polymer (P) may contain the structural unit (A) and the structural unit (B), and at least a part of the structural unit (A) has a crosslinkable group R c In terms of forming a liquid crystal alignment film showing weak anchoring properties and making the liquid crystal alignment property and the adhesion of the liquid crystal alignment film of the liquid crystal element more excellent, the polymer (P) is preferably a polymer containing the structural unit (A) and the structural unit (B) together.

[0089] From the viewpoint of copolymerizability with the structural unit (A), the structural unit (B) is preferably a structural unit derived from an ethylenically unsaturated monomer. From the viewpoint of exhibiting weak anchoring properties, a structural unit derived from at least one selected from the group consisting of (meth)acrylic monomers and styrene monomers is more preferable, and a structural unit derived from a (meth)acrylic monomer is further preferable.

[0090] Specific examples of the monomer providing the structural unit (B) include compounds represented by the following formulas (b-1) to (b-25), respectively.

[0091] [Chemical formula 5]

[0092]

[0093] If the structural unit having a crosslinkable group R c is further described (that is, the structural unit (B) and the structural unit (A) in the case of having a crosslinkable group R c ), examples of the monomer providing the structural unit having a hydroxyl group or a protected hydroxyl group include the monomers represented by the above formulas (b-1) to (b-7), respectively.

[0094] Examples of the monomer providing the structural unit having a protected amino group, a thiol group or a protected thiol group include the compounds represented by the above formulas (b-8) to (b-10), respectively.

[0095] Examples of the monomer that provides a structural unit having a carboxyl group, a protected carboxyl group, or an acid anhydride group include the compounds represented by the formulas (b-11) to (b-16), respectively.

[0096] Examples of the monomer that provides a structural unit having an oxiranyl group, a protected oxiranyl group, or an oxetanyl group include the compounds represented by the formulas (b-17) to (b-21), respectively.

[0097] Examples of the monomer that provides a structural unit having a protected isocyanate group include the compounds represented by the formulas (b-22) to (b-25), respectively.

[0098] When the structural unit (A) has a crosslinkable group R c (preferably when the structural unit containing R 3 being a hydrogen atom in the formula (1) is used as the structural unit (A)), the crosslinkable group R c possessed by the structural unit (A) is preferably a hydroxyl group, a thiol group, or a carboxyl group, more preferably a hydroxyl group.

[0099] When the liquid crystal aligning agent satisfies the above-mentioned requirement (I), from the viewpoint of forming a liquid crystal alignment film showing good mechanical properties and adhesion, with respect to all the structural units of the polymer (P), the total content ratio of the structural unit having the first functional group and the structural unit having the second functional group in the polymer (P) (that is, when the structural unit (A) contains a structural unit having a crosslinkable group R c , the total amount of the structural unit (B) and the structural unit (A) having a crosslinkable group R c ) is preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 20% by mass or more. In addition, the ratio of the first functional group to the second functional group in the polymer (P) is preferably 0.2 mole to 5.0 moles of the second functional group relative to 1 mole of the first functional group, more preferably 0.5 mole to 2.0 moles.

[0100] When the liquid crystal aligning agent satisfies requirement (II) or requirement (III) among the above-mentioned requirements (I) to (III), from the viewpoint of forming a liquid crystal alignment film showing good mechanical properties and adhesion, with respect to all the structural units of the polymer (P), the content ratio of the structural unit having a crosslinkable group R c in the polymer (P) (the structural unit (B) and the structural unit having a crosslinkable group R cThe total amount of the structural unit (A) is preferably 5% by mass or more, more preferably 10% by mass or more. Further, from the viewpoint of suppressing the decrease in the weak anchoring property, with respect to all the structural units of the polymer (P), the structural unit having the crosslinkable group R c The content ratio is preferably 60% by mass or less, more preferably 40% by mass or less, and still more preferably 20% by mass or less.

[0101] When the polymer (P) contains the structural unit (B), with respect to all the structural units of the polymer (P), the content ratio of the structural unit (B) in the polymer (P) is preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 5% by mass or more. Further, from the viewpoint of suppressing the decrease in the weak anchoring property, with respect to all the structural units of the polymer (P), the content ratio of the structural unit (B) is 60% by mass or less, preferably 40% by mass or less, and still more preferably 20% by mass or less.

[0102] The polymer (P) may further contain a structural unit different from the structural unit (A) and the structural unit (B) (hereinafter, also referred to as "structural unit (C)"). From the viewpoint of copolymerizability with the structural unit (A), the structural unit (C) is preferably a structural unit derived from an ethylenically unsaturated monomer. From the viewpoint of exhibiting the weak anchoring property, it is more preferably a structural unit derived from at least one selected from the group consisting of (meth)acrylic monomers, styrene monomers, and maleimide monomers.

[0103] Specific examples of the monomer that provides the structural unit (C) include, for example: (meth)acrylic acid alkyl esters, (meth)acrylic acid alkenyl esters, (meth)acrylic acid aryl esters, (meth)acrylic acid hydroxyalkyl esters, (meth)acrylic acid alkoxyalkyl esters, (meth)acrylic acid alkyl esters containing a tertiary amino group, (meth)acrylic acid esters having an alicyclic hydrocarbon group, unsaturated carboxylic acids, aromatic vinyl compounds, (meth)acrylic acid esters of polyhydric alcohols, N-substituted maleimides, vinyl ethers, ethylenically unsaturated monomers having an oxygen-containing saturated heterocycle, and the like. From the aspect that the T of the polymer (P) can be sufficiently reduced g and a liquid crystal alignment film exhibiting the weak anchoring property can be obtained, the monomer that provides the structural unit (C) is still more preferably a structural unit derived from a (meth)acrylic monomer.

[0104] As another specific example of the monomer that provides the structural unit (C), for example, the compounds represented by the following formulas (c-1) to (c-11) can be cited.

[0105] [Chemical formula 6]

[0106]

[0107] In terms of suppressing the reduction of the weak anchoring property or close contact property, the content ratio of the structural unit (C) in the polymer (P) is preferably 40% by mass or less, more preferably 20% by mass or less, and still more preferably 10% by mass or less, relative to all the structural units of the polymer (P).

[0108] Here, for the monomer that provides the structural unit (A), the monomer that provides the structural unit (B), and the monomer that provides the structural unit (C), the glass transition temperature T of the homopolymer of each monomer g The literature values and calculated values are shown in Tables 1 to 3 below. In addition, for the homopolymers of each monomer, in order to evaluate the hydrophobicity, the Hildebrand solubility parameter δ was determined using the computer software HSPiP (version 5.4.08) Tot (MPa 1 / 2 ), and these values are shown in Tables 1 to 3 below. In addition, the notations of the monomer types in Tables 1 to 3 correspond to the compounds represented by the formulas (a-1) to (a-26), the formulas (b-1), (b-2), (b-5), (b-9), (b-12) to (b-14), (b-17), (b-20), (b-22), and the formulas (c-1) to (c-11), respectively. In Tables 1 to 3, "T g,exp " represents the literature value, and "T g,calc " represents the calculated value. In addition, a) and b) in Tables 1 to 3 represent the reference sources of the literature values, specifically as follows.

[0109] a) Literature value (median value) recorded in the "Polymer Database 'PoLyInfo'" of the National Institute of Materials Science

[0110] b) Experimental value recorded in the "Blemmer (registered trademark) series comprehensive catalog" of NOF Corporation

[0111] The calculated value of the glass transition temperature T g (T g,calc ) is a calculated value based on molecular dynamics calculations (all-atom model, charge AM1-BCC, force field GAFF2, about 10,000 atoms, pressure 1 atm, temperature 600 K to 100 K).

[0112] [Table 1]

[0113]

[0114] [Table 2]

[0115]

[0116] [Table 3]

[0117]

[0118] In terms of obtaining a liquid crystal alignment film exhibiting good weak anchoring properties, the glass transition temperature of the homopolymer of the monomer providing the structural unit (A) is preferably -100°C or higher and 0°C or lower, more preferably -100°C or higher and -10°C or lower, still more preferably -100°C or higher and -20°C or lower, and even more preferably -100°C or higher and -30°C or lower.

[0119] In addition, although the present invention is not limited thereto, the closer the solubility parameter of the liquid crystal alignment film and the liquid crystal composition is, the more easily the liquid crystal alignment film swells due to the liquid crystal composition, and the apparent glass transition temperature decreases, so it is considered that good weak anchoring properties are easily exhibited. On the other hand, the closer the solubility parameter of the liquid crystal alignment film and the liquid crystal sealant is, the higher the adhesion between the liquid crystal alignment film and the liquid crystal sealant is, and it is considered that good sealant adhesion is easily exhibited. In addition, generally, it is known that the closer the solubility parameter of the adhesive and the adherend is, the higher the adhesion is (for example, refer to the non-patent literature "Y. Iyengar and D.E. Erickson, Journal of Applied Polymer Science, 11, 2311 - 2324 (1967).").

[0120] Here, for a bisphenol A type epoxy resin as a representative example of the liquid crystal sealant and liquid crystal compounds represented by the following formulas (lc-1) to (lc-3) as representative examples of the liquid crystal composition, the values of the solubility parameters are shown in Table 4 below. In addition, the solubility parameter of the epoxy resin is referred to the non-patent literature "Hansen, C.M., Hansen solubility parameters: A user's handbook. 2000", Boca Raton, Fla: CRC Press, and the solubility parameter of the liquid crystal compound is obtained using the computer software HSPiP (version 5.4.08).

[0121] [Chemical Formula 7]

[0122]

[0123] [Table 4]

[0124]

[0125] From the perspective of obtaining a liquid crystal alignment film with good sealant adhesion, the solubility parameter δ of the homopolymer of the monomer of structural unit (A) Tot (MPa 1 / 2 ) is preferably 19 or more and less than 27, more preferably 20 or more and less than 26, and still more preferably 21 or more and less than 25.

[0126] The polymer (P) can be a homopolymer or a copolymer. In addition, when the polymer (P) is a copolymer, it can be any of a random copolymer, a block copolymer, a graft copolymer, etc. Furthermore, there is no particular limitation on the production method of the polymer (P). The polymer (P) can be produced, for example, by known methods such as radical polymerization, anionic polymerization, cationic polymerization, living radical polymerization, living anionic polymerization, and living cationic polymerization.

[0127] When synthesizing the polymer (P), all the monomers used in the synthesis of the polymer (P) can be polymerized together, or a macromonomer can be synthesized by polymerizing a part of the monomers and then the macromonomer is polymerized with the remaining monomers to obtain the desired polymer. Here, the macromonomer is a monomer with a relatively high molecular weight having a polymerizable functional group, and examples thereof include n-butyl acrylate. In addition, when synthesizing the polymer (P), commercially available products of macromonomers can also be used. As such a macromonomer, for example, a macromonomer having a mono(meth)acryloyl group at the end of the polymer molecular chain, commercially available from Toagosei Co., Ltd., can be cited.

[0128] ·Molecular weight characteristics

[0129] For the polymer (P), the polystyrene-equivalent weight-average molecular weight (Mw) measured by gel permeation chromatography (GPC) is preferably 1,000 to 100,000. The M w of the polymer (P) is preferably 3,000 or more. In addition, the M w of the polymer (P) is preferably 50,000 or less. If M w is 1,000 or more, the mechanical properties and adhesion of the liquid crystal alignment film can be made better, which is preferable in terms of the above aspects. If M w is 100,000 or less, the coatability can be made good, which is preferable in terms of the above aspects.

[0130] The ratio (M w ) of the number-average molecular weight (M n ) to the weight-average molecular weight (M w / M n) The molecular weight distribution represented is preferably from 1.0 to 5.0, more preferably from 1.0 to 3.0. In addition, M w and M n are polystyrene conversion values measured by GPC using tetrahydrofuran as the eluting solvent.

[0131] · Glass transition temperature

[0132] The glass transition temperature (Tg) of the polymer (P) is preferably -100 °C or higher and 20 °C or lower. If the glass transition temperature of the polymer (P) is within the above range, the Tg of the film surface of the liquid crystal alignment film becomes sufficiently low, and good weak anchoring properties can be exhibited, which is preferable in this regard. From this viewpoint, the Tg of the polymer (P) is more preferably -100 °C or higher and 0 °C or lower, and still more preferably -100 °C or higher and -20 °C or lower. In the present specification, the Tg of the polymer (P) is a value calculated from the Tg of the homopolymer of each monomer constituting the polymer (P) by the Fox formula (refer to the following formula (I)).

[0133] [Equation 1]

[0134]

[0135] (In formula (I), Tg is the Tg of the copolymer. Wi is the mass fraction of monomer unit i. Tgi is the T g )

[0136] In addition, the T g of the crosslinked film can be calculated by the Fox-Loshaek formula (refer to the following formula (II)) from the T g of the polymer (P) contained in the liquid crystal aligning agent used to form the crosslinked film and the crosslinking density.

[0137] [Equation 2]

[0138]

[0139] (In formula (II), T g c is the T g of the crosslinked film. K 2 is a constant inherent to the polymer. X c is the crosslinking density represented by the molar ratio of the structural unit having a crosslinkable group)

[0140] K 2Generally, the report has a range of 0.5 to 1.0 (for example, refer to the non-patent literature "H. Stutz, K.-H. Illers, and J. Mertes, 'A Generalized Theory for the Glass Transition Temperature of Crosslinked and Uncrosslinked Polymers', 'Journal of Polymer Science: Part B: Polymer Physics', 28, 1483-1498 (1990).") and the non-patent literature "T.G. Fox and S. Loshaek, 'Journal of Polym. Sci.', 15, 371 (1955).").

[0141] In the liquid crystal aligning agent of the present disclosure, the content of the polymer (P) is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total amount of the solid components (i.e., components other than the solvent of the liquid crystal aligning agent) contained in the liquid crystal aligning agent.

[0142] <Compound (D)>

[0143] Compound (D) has two or more functional groups capable of reacting with the crosslinkable group R possessed by the polymer (P) c to form a bond (hereinafter, also referred to as "functional group R" L "). Among them, compound (D) is a compound different from the polymer (P). As the functional group R L possessed by compound (D), the same groups as those described for the second functional group that the polymer (P) may have can be exemplified. In addition, the preferred combination of the functional group R L possessed by compound (D) and the crosslinkable group R c possessed by the polymer (P) is the same as that shown by the preferred combination of the first functional group and the second functional group possessed by the polymer (P).

[0144] From the viewpoint of obtaining a liquid crystal alignment film that exhibits good weak anchoring properties while having excellent mechanical properties and adhesion, the number of the functional groups R L possessed by compound (D) in one molecule is preferably two to ten, more preferably two to six. In addition, the molecular weight of compound (D) is preferably 100 to 1,000, more preferably 100 to 800, and still more preferably 100 to 600.

[0145] Regarding specific examples of compound (D), as a compound having a protected isocyanate group, for example, there may be mentioned: compounds in which the isocyanate group in toluene diisocyanate, xylene diisocyanate, chlorobenzene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate or diphenylmethane diisocyanate is protected by 3,6-dimethylpyrazole, methyl ethyl ketoxime, diethyl malonate or ε-caprolactam, compounds represented by the following formula (d1-1), etc.;

[0146] As a compound having an oxiranyl group, a protected oxiranyl group or an oxetanyl group, for example, there may be mentioned: ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, tris(2,3-epoxypropyl) isocyanurate, glycerol polyglycidyl ether, pentaerythritol tetraglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, N,N,N',N'-tetraglycidylglycoluril, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N-diglycidyl-benzylamine, N,N-diglycidyl-aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine, the epoxidation reaction product formed by hydrogen peroxide of 2,2'-diallylbisphenol A diallyl ether, compounds represented by the following formula (d4-1) and formula (d4-2), etc.;

[0147] As a compound having a mercapto group or a protected mercapto group, there may be mentioned: 1,2-ethanedithiol, 1,3-propanedithiol, 1,3,4-thiadiazole-2,5-dithiol, 1,10-decanedithiol, pentaerythritol tetra(3-mercaptobutyrate), 1,3,5-tris(2-(3-mercaptobutyryloxy)ethyl)-1,3,5-triazacyclohexane-2,4,6-trione, etc.;

[0148] As a compound having a carboxyl group, a protected carboxyl group or an acid anhydride group, there may be mentioned: maleic acid, itaconic acid, trimellitic acid, tetracarboxylic acid, cis-1,2,3,4-tetrahydrophthalic acid, ethylene glycol bis(trimellitate), propylene glycol bis(trimellitate), 4,4'-oxybisphthalic acid, trimellitic anhydride, etc.;

[0149] As a compound having a hydroxyl group or a protected hydroxyl group, for example, there may be mentioned compounds represented by the following formula (d3-1) to formula (d3-6), formula (d6-1) to formula (d6-8), etc.;

[0150] Examples of the compound having a protected amino group include compounds represented by the following formula (d7-1) to formula (d7-4).

[0151] [Chemical formula 8]

[0152]

[0153] [Chemical formula 9]

[0154]

[0155] [Chemical formula 10]

[0156]

[0157] (In formula (d3-5), Ac is an acetyl group)

[0158] [Chemical formula 11]

[0159]

[0160] [Chemical formula 12]

[0161]

[0162] When the liquid crystal aligning agent of the present disclosure contains the compound (D), from the viewpoint of obtaining a liquid crystal alignment film showing weak anchoring properties and improving the mechanical properties and adhesion of the liquid crystal alignment film, the content of the compound (D) is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the total amount of the polymer components (that is, the total amount of the polymer (P) and other polymers). With respect to 100 parts by mass of the total amount of the polymer components, the content of the compound (D) is more preferably 1 part by mass or more, and further preferably 2 parts by mass or more. In addition, from the viewpoint of obtaining a liquid crystal element showing good liquid crystal alignment properties, the content of the compound (D) is preferably 50 parts by mass or less, and more preferably 40 parts by mass or less with respect to 100 parts by mass of the total amount of the polymer components.

[0163] <Other components>

[0164] The liquid crystal aligning agent of the present disclosure may contain components different from the polymer (P) and the compound (D) (hereinafter, also referred to as "other components") as needed. Examples of the other components include polymers different from the polymer (P) (hereinafter, also referred to as "other polymers"), adhesion aids, solvents, and the like.

[0165] · Other polymers

[0166] Other polymers may be any polymers that do not have the structural unit (A) represented by the formula (1), and the type of the main skeleton is not particularly limited. Examples of other polymers include polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamideimide, addition polymer, etc. From the viewpoint of obtaining a liquid crystal element with high reliability, other polymers are preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, and addition polymer, and more preferably at least one selected from the group consisting of polyamic acid and addition polymer. Examples of addition polymers include (meth)acrylic polymers, styrene polymers, maleimide polymers, (meth)acrylic-styrene copolymers, (meth)acrylic-maleimide copolymers, (meth)acrylic-styrene-maleimide copolymers, and styrene-maleimide copolymers, etc.

[0167] As other polymers, polymers having a functional group capable of reacting with the crosslinkable group R c possessed by the polymer (P) to form a bond (i.e., functional group R L ) can be preferably used. Examples of the functional group R L possessed by other polymers include the same groups as those described for the second functional group that the polymer (P) may have. In addition, the preferred combination of the functional group R L possessed by other polymers and the crosslinkable group R c possessed by the polymer (P) is the same as that shown for the preferred combination of the first functional group and the second functional group possessed by the polymer (P).

[0168] When other polymers have the functional group R L , other polymers are preferably those containing a structural unit having the functional group R L . In other polymers, from the viewpoint of sufficiently obtaining the effect of improving the adhesion, the content ratio of the structural unit having the functional group R L is preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 5% by mass or more, based on the total amount of the structural units of the monomer source constituting the other polymers. In addition, from the viewpoint of suppressing the decrease in the weak anchoring property, the content ratio of the structural unit having the functional group R L is preferably 60% by mass or less, based on the total amount of the structural units of the monomer source constituting the other polymers.

[0169] When blending other polymers in the liquid crystal aligning agent, the content of the other polymer is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, based on 100 parts by mass of the polymer components (i.e., the total amount of the polymer (P) and the other polymer) contained in the liquid crystal aligning agent.

[0170] · Adhesion promoter

[0171] The adhesion promoter is a component that improves the adhesion between the liquid crystal alignment film formed using the liquid crystal aligning agent and the substrate or the sealant. As the adhesion promoter, a functional silane coupling agent having a reactive functional group can be preferably used. Examples of the reactive functional group possessed by the functional silane coupling agent include: carboxyl group, (meth)acryloyl group, oxiranyl group, oxetanyl group, vinyl group, isocyanate group, etc.

[0172] Specific examples of the functional silane coupling agent include, for example: trimethoxysilylbenzoic acid, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, etc.

[0173] When the liquid crystal aligning agent of the present disclosure contains an adhesion promoter, the content of the adhesion promoter is preferably 0.1 part by mass to 20 parts by mass, more preferably 0.2 part by mass to 10 parts by mass, based on 100 parts by mass of the polymer components contained in the liquid crystal aligning agent.

[0174] · Solvent

[0175] The liquid crystal aligning agent of the present disclosure is prepared in the form of a liquid composition in which the polymer (P) and the components used as needed are preferably dispersed or dissolved in an appropriate solvent.

[0176] As the solvent, an organic solvent can be preferably used. Specific examples thereof include: amides such as N,N-dimethylformamide, N,N-dimethylacetamide; lactams such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactam; ureas such as 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone; lactones such as γ-butyrolactone; carbonates such as ethylene carbonate, propylene carbonate;

[0177] Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, etc. (poly)alkylene glycol monoalkyl ethers;

[0178] Methyl lactate, ethyl lactate, butyl lactate and other alkyl lactates; alkyl alcohols such as methanol, ethanol, propanol, butanol, isopropanol, isobutanol, tert-butanol, octanol, 2-ethylhexanol, cyclohexanol, etc., which may have a straight-chain, branched or cyclic structure; alkoxy alcohols such as 3-methoxy-1-butanol; ketone alcohols such as diacetone alcohol; (poly)alkylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, etc.; ethers such as diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, tetrahydrofuran; ketones such as methyl ethyl ketone, diisobutyl ketone, cyclohexanone, cyclopentanone, 2-heptanone, 3-heptanone;

[0179] Diacetates such as propylene glycol diacetate, 1,3-butanediol diacetate, 1,6-hexanediol diacetate; alkoxycarboxylic acid esters such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxyacetate, 3-methyl-3-methoxybutyl propionate; other esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl formate, isoamyl acetate, n-butyl propionate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-butyl butyrate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl 2-oxobutyrate; aromatic hydrocarbons such as toluene, xylene; phenols such as phenol, cresol.

[0180] As other components formulated in the liquid crystal aligning agent, in addition to those described above, for example, surfactants, antioxidants, metal chelating compounds, hardening accelerators, fillers, dispersants, photosensitizers, etc. can be cited. The blending ratio of other components can be appropriately selected according to each compound within the range that does not impair the effects of the present disclosure.

[0181] The solid content concentration in the liquid crystal aligning agent (the proportion of the total mass of the components other than the solvent of the liquid crystal aligning agent in the total mass of the liquid crystal aligning agent) can be appropriately selected in consideration of viscosity, volatility, etc. The solid content concentration of the liquid crystal aligning agent is preferably in the range of 1% by mass to 10% by mass. If the solid content concentration is 1% by mass or more, the film thickness of the coating film can be sufficiently ensured, and a liquid crystal alignment film showing better liquid crystal alignment properties can be obtained, which is preferable in this regard. In addition, if the solid content concentration is 10% by mass or less, the coating film can be set to an appropriate thickness, and it is easy to obtain a liquid crystal alignment film showing good liquid crystal alignment properties. Furthermore, the viscosity of the liquid crystal aligning agent becomes appropriate, and good coatability can be ensured.

[0182] Weak Anchoring Liquid Crystal Alignment Film

[0183] The liquid crystal alignment film of the present disclosure is a weak anchoring film manufactured using the liquid crystal aligning agent prepared as described above. Here, the so-called "weak anchoring" means that the alignment restraining force of liquid crystal molecules is substantially zero in the in-plane direction, and even if the horizontal alignment of liquid crystal molecules is forced, the alignment restraining force in the in-plane direction is substantially zero. In the state of weak anchoring (also called zero surface anchoring), through the control of external fields such as electric fields and magnetic fields, the in-plane alignment direction can be freely rotated by 360°.

[0184] The method for manufacturing a weak anchoring liquid crystal alignment film using the liquid crystal aligning agent of the present disclosure is not particularly limited, and the same method as that for manufacturing a liquid crystal alignment film using a conventionally known liquid crystal aligning agent can be used. In terms of easy film formation, a method of forming by coating the liquid crystal aligning agent of the present disclosure on a substrate and preferably heating the coating surface is preferred.

[0185] The substrate for forming the liquid crystal alignment film is not particularly limited. As the substrate, for example, the following transparent substrates can be used: glass such as float glass and soda glass; plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefin).

[0186] The method for coating the liquid crystal aligning agent on the substrate is not particularly limited. The coating of the liquid crystal aligning agent can be carried out, for example, by spin coating, printing methods (e.g., offset printing method, flexographic printing method, etc.), inkjet method, slit coating method, bar coater method, extrusion die method, direct gravure coater method, chamber doctor coater method, offset gravure coater method, impregnation coating method, MB coater method, etc.

[0187] After applying the liquid crystal aligning agent, preheating (pre-baking) is preferably carried out for the purpose of preventing the liquid crystal aligning agent from sagging or the like. The pre-baking temperature is preferably 30°C to 200°C, and the pre-baking time is preferably 0.25 minutes to 10 minutes. Thereafter, a calcination (post-baking) process is carried out for the purpose of further removing the solvent. The calcination temperature (post-baking temperature) is preferably 80°C to 280°C, more preferably 80°C to 250°C. The post-baking time is preferably 5 minutes to 200 minutes. The film thickness of the formed film is preferably 0.001 μm to 2.5 μm.

[0188] By the above-described operation, a weak-anchoring liquid crystal alignment film can be simply manufactured. Here, it has been reported that: the higher the hydrophobicity of the film surface (i.e., the lower the surface free energy of the film surface), the easier the pretilt angle of the liquid crystal molecules rises, and the easier the liquid crystal molecules are vertically aligned (Non-Patent Document “Langmuir 2006, 22, 23, 9753-9759”, “Anchoring of a Nematic Liquid Crystal on a Wettability Gradient”). That is, when considering the application of the weak-anchoring liquid crystal alignment film to the IPS mode or FFS mode in which the liquid crystal is horizontally aligned with respect to the substrate, it is considered ideal to suppress the hydrophobicity of the film surface, thereby suppressing the vertical alignment of the liquid crystal molecules. In terms of the above aspect, the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present disclosure is formed of a polymer (P) containing 50% by mass or more of the structural unit (A), the hydrophobicity of the film surface is sufficiently low, and the vertical alignment of the liquid crystal molecules can be suppressed. In addition, the glass transition temperature of the polymer (P) containing 50% by mass or more of the structural unit (A) is sufficiently low, and the intermolecular interaction at the interface between the liquid crystal alignment film and the liquid crystal molecules is weak. Therefore, it is considered that the molecular mobility of the liquid crystal molecules is sufficiently improved, thereby achieving a weak-anchoring behavior (sliding interface). Moreover, the hydrophobicity of the surface of the liquid crystal alignment film formed of the polymer (P) is sufficiently low, and the intermolecular interaction with the sealant component formed on the liquid crystal alignment film is sufficiently high, whereby the adhesion to the sealant is excellent.

[0189] In addition, the hydrophobicity of the film surface can be measured by experimental methods such as liquid contact angle measurement or surface free energy measurement. In addition, the hydrophobicity of the polymer can be estimated by molecular dynamics simulation or group contribution method. For example, commercially available computer software can be used to estimate the Hildebrand solubility parameter or Hansen solubility parameter based on the chemical structure of the polymer and the group contribution method. The solubility parameter is defined as the square root of the cohesive energy density, and can simply evaluate the hydrophobicity or adhesion.

[0190] 《Liquid Crystal Element》

[0191] The liquid crystal element of the present disclosure includes a weakly anchored liquid crystal alignment film formed using the liquid crystal aligning agent described in the above. The driving method 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) type, Super Twisted Nematic (STN) type, Vertical Alignment (VA) type (including Vertical Alignment-Multi-domain Vertical Alignment (VA-MVA) type, Vertical Alignment-Patterned Vertical Alignment (VA-PVA) type, etc.), In-Plane Switching (IPS) type, Fringe Field Switching (FFS) type, Optically Compensated Bend (OCB) type, Polymer Sustained Alignment (PSA) type, Electrically Controlled Birefringence (ECB) type, etc. Among these, it can be preferably applied to liquid crystal elements of horizontal modes such as IPS type or FFS type. The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. The substrate used in step 1 varies depending on the desired operation mode. Steps 2 and 3 are common to each operation mode.

[0192] <Step 1: Formation of a coating film>

[0193] First, by coating a liquid crystal aligning agent on each substrate surface of a pair of substrates, preferably heating the coating surface to form a coating film on the substrate. In the liquid crystal element of the present disclosure, preferably, a liquid crystal aligning agent for forming a strongly anchored liquid crystal alignment film is coated on one substrate of the pair of substrates, and the liquid crystal aligning agent of the present disclosure (i.e., the liquid crystal aligning agent for forming a weakly anchored film) is coated on the other substrate. As the liquid crystal aligning agent for forming a strongly anchored liquid crystal alignment film, a conventionally known liquid crystal aligning agent can be suitably used.

[0194] Regarding the pair of substrates, for example, in the case of manufacturing an IPS type or FFS type liquid crystal element, a substrate provided with electrodes patterned in a comb shape (hereinafter, also referred to as "first substrate") and a counter substrate without electrodes (hereinafter, also referred to as "second substrate") are used. As the electrodes, a transparent conductive film can be cited. As the transparent conductive film, a NESA film (registered trademark of PPG Industries, Inc., USA) containing tin oxide (SnO 2 ) or indium tin oxide (In 2 O 3 -SnO2 ) such as indium tin oxide (ITO) films. As an example of a state when forming a liquid crystal alignment film on the first substrate and the second substrate, a state where a strong anchoring liquid crystal alignment film is formed on the first substrate and a weak anchoring liquid crystal alignment film is formed on the second substrate can be cited.

[0195] <Process 2: Alignment treatment>

[0196] In the case of manufacturing an IPS type or FFS type liquid crystal element, for the coating film formed in the above Process 1, a treatment for imparting liquid crystal alignment ability (alignment treatment) is performed. As the alignment treatment, a rubbing treatment using cotton or nylon, etc. to wipe the surface of the coating film formed on the substrate, or a photo-alignment treatment for irradiating the coating film with light to impart liquid crystal alignment ability can be preferably used. The alignment treatment can be performed on the coating film formed on the first substrate and the coating film formed on the second substrate respectively, or can be performed only on one of the coating film formed on the first substrate and the coating film formed on the second substrate. From the viewpoint of obtaining a liquid crystal element showing good liquid crystal alignment property, it is preferable to coat a liquid crystal aligning agent for forming a strong anchoring liquid crystal alignment film and perform the alignment treatment only on the coating film thus formed.

[0197] Furthermore, according to the weak anchoring liquid crystal alignment film formed from the liquid crystal aligning agent of the present disclosure, even without performing alignment treatments such as rubbing treatment or photo-alignment treatment, a liquid crystal element showing good liquid crystal alignment property can be obtained. This property can also be utilized to configure the weak anchoring liquid crystal alignment film formed from the liquid crystal aligning agent of the present disclosure as a protective film provided on a color filter in a liquid crystal element, so that the weak anchoring liquid crystal alignment film has a function as a protective film (specifically, planarization, or protection from impurities, humidity, etc.).

[0198] <Process 3: Construction of a liquid crystal cell>

[0199] Prepare two substrates formed with liquid crystal alignment films as described above to manufacture a liquid crystal cell in which a liquid crystal layer is disposed between two oppositely disposed substrates. When manufacturing the liquid crystal cell, for example, the following methods, etc. can be cited: a method of disposing two substrates oppositely with a gap therebetween with the liquid crystal alignment films facing each other, bonding the peripheral portions of the two substrates with a sealant, injecting and filling liquid crystal into the cell gap surrounded by the substrate surface and the sealant, and sealing the injection hole; a method using the One Drop Fill (ODF) method. As the sealant, for example, an epoxy resin containing a hardening agent and alumina balls as spacers can be used. As the liquid crystal constituting the liquid crystal layer, nematic liquid crystals and smectic liquid crystals can be cited, and among them, nematic liquid crystals are preferred.

[0200] In the case of manufacturing a liquid crystal display device, a polarizing plate is then adhered to the outer surface of the liquid crystal cell. Examples of the polarizing plate include a polarizing plate in which a polarizing film called an "H film" obtained by stretching and orienting polyvinyl alcohol and absorbing iodine therein is sandwiched between cellulose acetate protective films, or a polarizing plate including the H film itself.

[0201] The liquid crystal element of the present disclosure can be effectively applied to various uses. Specifically, for example, it can be used as various display devices such as a clock, a portable game machine, a word processor, a notebook personal computer, a car navigation system, a camcorder, a personal digital assistant (PDA), a digital camera, a mobile phone, a smart phone, various monitors, a liquid crystal television, an information display, or a dimming device, a retardation film, etc.

[0202] According to the present disclosure described in detail above, the following means are provided.

[0203] 〔Means 1〕A liquid crystal aligning agent containing a polymer (P) including a structural unit (A) represented by the formula (1), wherein the content ratio of the structural unit (A) is 35% by mass or more with respect to all the structural units of the polymer (P), the polymer (P) has at least one crosslinkable group selected from the group consisting of a hydroxyl group, a protected hydroxyl group, a protected amino group, a thiol group, a protected thiol group, a carboxyl group, a protected carboxyl group, an acid anhydride group, an oxiranyl group, a protected oxiranyl group, an oxetanyl group, and a protected isocyanate group, and the liquid crystal aligning agent satisfies at least any one of the above-mentioned requirements (I), (II), and (III).

[0204] 〔Means 2〕The liquid crystal aligning agent according to 〔Means 1〕, wherein the polymer (P) further includes a structural unit (B) having the crosslinkable group (excluding the structural unit (A)).

[0205] 〔Means 3〕The liquid crystal aligning agent according to 〔Means 1〕 or 〔Means 2〕, wherein the glass transition temperature of the polymer (P) is -100°C or more and 20°C or less.

[0206] 〔Means 4〕The liquid crystal aligning agent according to any one of 〔Means 1〕 to 〔Means 3〕, wherein the glass transition temperature of the homopolymer of the monomer providing the structural unit (A) is -100°C or more and 0°C or less.

[0207] 〔Means 5〕The liquid crystal aligning agent according to any one of 〔Means 1〕 to 〔Means 4〕, including the structural unit in which R 3 in the formula (1) is a hydrogen atom as the structural unit (A).

[0208] [Means 6] The liquid crystal aligning agent according to any one of [Means 1] to [Means 5] further contains at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

[0209] [Means 7] The liquid crystal aligning agent according to any one of [Means 1] to [Means 6] is used for forming a weakly anchoring liquid crystal alignment film.

[0210] [Means 8] A weakly anchoring liquid crystal alignment film is formed using the liquid crystal aligning agent according to any one of [Means 1] to [Means 7].

[0211] [Means 9] A liquid crystal element includes the weakly anchoring liquid crystal alignment film according to [Means 8].

[0212] [Examples]

[0213] Hereinafter, it will be described more specifically by way of examples, but the present invention is not limited to these examples.

[0214] <Structure and Abbreviation of Compounds>

[0215] The structures and abbreviations of the main compounds used in the following examples are as follows.

[0216] [Free Radical Polymerizable Monomers]

[0217] Compounds (A-1) to (A-9): Compounds represented by the following formulas (A-1) to (A-9) respectively

[0218] [Chemical Formula 13]

[0219]

[0220] Compounds (B-1) to (B-8): Compounds represented by the following formulas (B-1) to (B-8) respectively

[0221] [Chemical Formula 14]

[0222]

[0223] Compounds (C-1) to (C-3): Compounds represented by the following formulas (C-1) to (C-3) respectively

[0224] [Chemical Formula 15]

[0225]

[0226] [Tetracarboxylic Dianhydride]

[0227] Dianhydrides (TA-1) to Dianhydrides (TA-4): Compounds represented by the following formulas (TA-1) to (TA-4) respectively

[0228] [Chemical formula 16]

[0229]

[0230] [Diamine]

[0231] Diamines (DA-1) to Diamines (DA-6): Compounds represented by the following formulas (DA-1) to (DA-6) respectively

[0232] [Chemical formula 17]

[0233]

[0234] [Additive]

[0235] Compounds (AD-1) to Compounds (AD-5): Compounds represented by the following formulas (AD-1) to (AD-5) respectively [Chemical formula 18]

[0236]

[0237] [Solvent]

[0238] NMP: N-Methyl-2-pyrrolidone

[0239] BC: Butyl cellosolve

[0240] <Synthesis and Evaluation of Polymer>

[0241] Polymers are synthesized respectively by the following Synthesis Examples 1 to 49. In addition, in the following examples, the weight average molecular weight (M w ) and number average molecular weight (M n ), the imidization rate of polyimide in the polymer solution, and the glass transition temperature (T g ) of the polymer are measured by the following methods.

[0242] [Weight average molecular weight (M w ) and number average molecular weight (M n )]

[0243] M w and M n are polystyrene conversion values measured by GPC under the following conditions.

[0244] Column: Manufactured by Tosoh Corporation, TSKgel GRCXLII

[0245] Solvent: Tetrahydrofuran

[0246] Temperature: 40 °C

[0247] Pressure: 68 kgf / cm 2

[0248] [Imidization rate of polyimide]

[0249] The solution of polyimide was poured into pure water. After the obtained precipitate was sufficiently dried under reduced pressure at room temperature, it was dissolved in deuterated dimethyl sulfoxide. Using tetramethylsilane as the reference substance, hydrogen nuclear magnetic resonance ( 1 H-Nuclear Magnetic Resonance, 1 H-NMR) measurement was carried out at room temperature. According to the obtained 1 H-NMR spectrum (400 MHz), the imidization rate [%] was calculated using the following formula (3).

[0250] Imidization rate [%] = (1 - (A 1 / (A 2 × α))) × 100 ·…· (3)

[0251] (In formula (3), A 1 is the peak area derived from the protons of the amide group appearing around 10 ppm in chemical shift, A 2 is the peak area derived from the protons of the aromatic group appearing around 6 ppm - 9 ppm in chemical shift, and α is the ratio of the number of protons of the aromatic group to one proton of the amide group in the precursor (polyamic acid) of the polymer)

[0252] [Glass transition temperature (T g ) of the polymer]

[0253] The T g of the polymer was calculated using the T g of the homopolymer of each monomer and by the Fox formula. In addition, the T g of the homopolymer of each monomer refers to the values shown in Table 1 - Table 3 described above.

[0254] [Solubility parameter (δ Tot ) of the polymer]

[0255] The δ Tot of the polymer was calculated using the δ Tot of the homopolymer of each monomer and by weighted average. In addition, the δ Tot of the homopolymer of each monomer uses the values shown in Table 1 - Table 3 described above.

[0256] [Synthesis Example 1]

[0257] 4.00 g of compound (A-1) as a radically polymerizable monomer, 1.00 g of compound (B-5), 0.15 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, and 20 mL of NMP as a solvent were added to a reaction vessel, and the reaction was carried out at 70 °C for 6 hours while stirring under a nitrogen stream to obtain a 25 mass% solution of polymer (P-1). The obtained polymer (P-1) had an M w of 32,000 and an M n of 15,000, and a T g of -37 °C.

[0258] [Synthesis Examples 2 to 39]

[0259] The types and amounts of the radically polymerizable monomers were changed as described in Table 5 below, and polymers (P-2) to (P-39) were obtained in the same manner as in Synthesis Example 1 except for this.

[0260] [Table 5]

[0261]

[0262] The values in Table 5 represent the use ratios (parts by mass) of the respective compounds relative to the total amount (100 parts by mass) of the radically polymerizable monomers used in the synthesis.

[0263] [Synthesis Example 40]

[0264] Diamine (50 mol parts of diamine (DA-1) and 50 mol parts of diamine (DA-2) relative to 100 mol parts of the total amount of diamine used) was dissolved in NMP, and 0.95 molar equivalent of tetracarboxylic dianhydride (50 mol parts of acid dianhydride (TA-1) and 50 mol parts of acid dianhydride (TA-3) relative to 100 mol parts of the total amount of tetracarboxylic dianhydride used) was added, and the reaction was carried out at room temperature for 6 hours to obtain a 15 mass% solution of polyamic acid (PI-1).

[0265] [Synthesis Example 41]

[0266] Diamine (DA-3) was dissolved in NMP, and 0.92 molar equivalent of acid dianhydride (TA-4) was added, and the reaction was carried out at room temperature for 6 hours to obtain a 15 mass% solution of polyamic acid (PI-2).

[0267] [Synthesis Example 42]

[0268] Dissolve diamines (40 mol parts of diamine (DA-4), 30 mol parts of diamine (DA-5), and 30 mol parts of diamine (DA-6) based on 100 mol parts of the total amount of diamines used) in NMP, and add 0.95 molar equivalents of tetracarboxylic dianhydride (TA-2) relative to the total amount of diamines. React at room temperature for 6 hours to obtain a solution of polyamic acid. Add 1-methylpiperidine and acetic anhydride, which are dehydrating agents, in an amount of 0.40 molar equivalents relative to the carboxyl groups of the polyamic acid to the obtained solution, and heat and stir at 60 °C for 3 hours. For the obtained solution, repeat concentration under reduced pressure and dilution with NMP to obtain a 10% by mass solution of polyimide (PI-3). The imidization rate of polyimide (PI-3) is 50%.

[0269] [Table 6]

[0270]

[0271] Regarding the values in Table 6, for the tetracarboxylic dianhydride, it represents the usage ratio (mol%) of each compound relative to the total amount (100 mol%) of the tetracarboxylic dianhydride used in the synthesis, and for the diamine, it represents the usage ratio (mol%) of each compound relative to the total amount (100 mol%) of the diamine used in the synthesis.

[0272] [Synthesis Example 43]

[0273] Change the types and amounts of the radically polymerizable monomers to 0.40 g of styrene, 0.60 g of N-phenylmaleimide, 2.00 g of compound (B-1), and 2.00 g of compound (B-3), and obtain a polymer (PS-1) in the same manner as in Synthesis Example 1.

[0274] [Synthesis Example 44]

[0275] Change the types and amounts of the radically polymerizable monomers to 0.80 g of styrene and 4.20 g of compound (B-3), and obtain a polymer (PS-2) in the same manner as in Synthesis Example 1.

[0276] <Preparation and Evaluation of Liquid Crystal Alignment Agent>

[0277] [Preparation Example 1: Strong Anchoring Liquid Crystal Alignment Agent for Photoalignment]

[0278] The polymer components (in terms of solid content: 60 parts by mass of polymer (PI-1) and 40 parts by mass of polymer (PI-3)), 5 parts by mass of crosslinking agent (AD-2), and 1 part by mass of adhesion promoter (AD-3) were diluted with NMP and BC to obtain a solution having a solid content concentration of 4.0% by mass and a solvent composition ratio of NMP:BC = 60:40 (mass ratio). The solution was filtered through a filter with a pore size of 0.2 μm to prepare a strongly anchoring liquid crystal aligning agent (AL-P1).

[0279] [Preparation Example 2: Strongly Anchoring Liquid Crystal Aligning Agent for Rubbing Alignment]

[0280] The polymer components (in terms of solid content: 60 parts by mass of polymer (PI-1) and 40 parts by mass of polymer (PI-2)), 5 parts by mass of crosslinking agent (AD-1), and 1 part by mass of adhesion promoter (AD-3) were diluted with NMP and BC to obtain a solution having a solid content concentration of 4.0% by mass and a solvent composition ratio of NMP:BC = 60:40 (mass ratio). The solution was filtered through a filter with a pore size of 0.2 μm to prepare a strongly anchoring liquid crystal aligning agent (AL-R1).

[0281] [Example 1: Photoalignment FFS-Type Liquid Crystal Display Element]

[0282] (1) Preparation of Weakly Anchoring Liquid Crystal Aligning Agent

[0283] 100 parts by mass of polymer (P-1) and 1 part by mass of adhesion promoter (AD-3) were diluted with NMP and BC to obtain a solution having a solid content concentration of 4.0% by mass and a solvent composition ratio of NMP:BC = 60:40 (mass ratio). The solution was filtered through a filter with a pore size of 0.2 μm to prepare a weakly anchoring liquid crystal aligning agent (AL-1).

[0284] (2) Fabrication and Evaluation of Liquid Crystal Display Element

[0285] Fabrication Figure 1 The FFS-type liquid crystal display element 10 shown in the figure was fabricated and subjected to various property evaluations. When fabricating the FFS-type liquid crystal display element 10, first, a substrate (referred to as the first substrate) having an electrode pair in which a bottom electrode 15 without a pattern, an insulating layer 14 of a silicon nitride film, and a top electrode 13 patterned into a comb shape were sequentially formed on one side of a glass substrate 11a, and an opposing glass substrate 11b without an electrode (referred to as the second substrate) were prepared.

[0286] The plan view of the top electrode 13 used is shown in Figure 2 in (a), Figure 2 in (b). In addition, Figure 2(a) is a top view of the top electrode 13. Figure 2 (b) of [is] Figure 2 An enlarged view of the portion C1 surrounded by the dashed line in (a) of [this figure]. In this embodiment, the line width d1 of the electrode is set to 4 μm, and the distance d2 between the electrodes is set to 6 μm. In addition, as the top electrode 13, four systems of driving electrodes, namely electrode A, electrode B, electrode C, and electrode D, are used ( Figure 3 ). In addition, the bottom electrode 15 functions as a common electrode that acts on all four systems of driving electrodes, and the regions of the four systems of driving electrodes respectively become pixel regions. In addition, Figure 1 In [the figure], the symbol 12 represents the liquid crystal alignment film, and the symbol 16 represents the liquid crystal layer.

[0287] (i) Formation of the liquid crystal alignment film by the photoalignment method

[0288] The strongly anchoring liquid crystal aligning agent (AL-P1) prepared in Preparation Example 1 was coated on the electrode formation surface of the first substrate using a spin coater. Subsequently, it was heated on a hot plate at 80 °C for 1 minute, and then heated in an oven at 230 °C with nitrogen replacement in the chamber for 30 minutes to form a coating film with an average film thickness of 100 nm. For the surface of the coating film, ultraviolet light containing a bright line of 254 nm linearly polarized light was irradiated from the substrate normal direction using a Hg-Xe lamp at 200 mJ / cm 2 for photoalignment treatment. At this time, the direction of the polarization plane of the polarized ultraviolet light projected onto the line segment on the substrate was set to be orthogonal to the direction of the double-headed arrow in Figure 2 (b) of [this figure]. The coating film subjected to the photoalignment treatment was heated in an oven at 230 °C with nitrogen replacement in the chamber for 30 minutes for heat treatment, thereby forming a strongly anchoring liquid crystal alignment film.

[0289] (ii) Formation of the weakly anchoring liquid crystal alignment film

[0290] The weakly anchoring liquid crystal aligning agent (AL-1) prepared in (1) above was coated on one surface of the second substrate using a spin coater. After heating on a hot plate at 80 °C for 1 minute, it was heated in an oven at 230 °C with nitrogen replacement in the chamber for 30 minutes to form a weakly anchoring liquid crystal alignment film with an average film thickness of 100 nm.

[0291] (iii) Manufacture of the FFS type liquid crystal display element

[0292] For the outer periphery of the surface having the liquid crystal alignment film in the substrates fabricated in the above (i) and (ii), a liquid crystal injection port is left, and an epoxy resin adhesive containing alumina balls with a diameter of 3.5 μm is coated using a dispenser. Thereafter, the surfaces of the pair of substrates having the liquid crystal alignment films are faced and pressed together, and the adhesive is thermally cured at 150 °C for 1 hour. Subsequently, a negative nematic liquid crystal (manufactured by Merck Co., Ltd., MLC-6608, Δn = 0.083) is filled into the gap between the substrates from the liquid crystal injection port, and then the liquid crystal injection port is sealed with an epoxy-based adhesive. Further, in order to remove the flow alignment during liquid crystal injection, it is heated at 120 °C and then slowly cooled to room temperature.

[0293] (iv) Evaluation of liquid crystal alignment

[0294] For the liquid crystal display element fabricated in the above (iii), in a polarizing microscope under crossed nicols, the change in brightness when a rectangular wave AC voltage of 5 V is turned on / off (applied / removed) is observed for any abnormal domains to evaluate the liquid crystal alignment. Regarding the evaluation, the case where no abnormal domains are observed is defined as "good", and the case where abnormal domains are observed is defined as "bad". As a result, in this example, the evaluation is "good".

[0295] (v) Evaluation of brightness

[0296] For the liquid crystal display element fabricated in the above (iii), the liquid crystal display element is clamped between a polarizer and an analyzer under crossed nicols, and a rectangular wave AC voltage is scanned in the range from 0 V to 8 V at 0.5 V intervals to measure the transmitted brightness of the liquid crystal display element. The transmitted brightness when no voltage is applied under parallel nicols is set as 100%, and the maximum transmittance is calculated based on the maximum transmitted brightness during voltage scanning. Regarding the evaluation, the case where the maximum transmittance is 70% or more is defined as "excellent", the case where the maximum transmittance is 65% or more and less than 70% is defined as "good", and the case where the maximum transmittance is less than 60% is defined as "bad". In addition, when the evaluation of the liquid crystal alignment is "bad", light leaks from the liquid crystal display element even when not driven, and it is inappropriate to perform the evaluation of brightness. Therefore, regardless of the value of the maximum transmittance, the evaluation result of brightness is set as "bad". As a result, in this example, the evaluation is "excellent".

[0297] (vi) Evaluation of adhesion

[0298] Using a spin coater, the weakly anchoring liquid crystal aligning agent (AL-1) prepared in (1) above and the strongly anchoring liquid crystal aligning agent (AL-P1) prepared in Preparation Example 1 were respectively coated on glass substrates. After heating on a hot plate at 80 °C for 1 minute, they were heated in an oven at 230 °C with nitrogen replacement in the chamber for 30 minutes, thereby fabricating two glass substrates with coatings having an average film thickness of 100 nm. Next, a liquid crystal sealant (manufactured by Sekisui Chemical Co., Ltd., S-WB21) was coated on the central portion of the surface of one glass substrate having the coating, and the other glass substrate was bonded in such a way that the coating contacted the liquid crystal sealant. The coating amount of the liquid crystal sealant was set so that the diameter of the liquid crystal sealant after substrate bonding became 4 mm. Thereafter, light with an energy of 30,000 J / m 2 (converted to 365 nm) was irradiated using a metal halide lamp, and then heated in an oven at 120 °C for 1 hour, thereby obtaining an evaluation cell. Thereafter, the evaluation cell was pressed using a small tabletop testing machine (model: EZ-LX) manufactured by Shimadzu Corporation, and the pressure (N) at which film peeling occurred (mainly peeling caused by interfacial failure between the liquid crystal sealant and the film or cohesive failure inside the liquid crystal sealant) was measured. By dividing the pressure (N) at the time of peeling by the area of the liquid crystal sealant (mm 2 ), the adhesion between the film, the liquid crystal sealant, and the substrate was calculated (N / mm 2 ). For the evaluation, when the measured value of the pressure was 1.5 N / mm 2 or more, it was regarded as "excellent", when it was 1.0 N / mm 2 or more and less than 1.5 N / mm 2 , it was regarded as "good", and when it was less than 1.0 N / mm 2 , it was regarded as "poor". As a result, in this example, the evaluation was "good".

[0299] [Examples 2 to 32, Comparative Examples 1 to 8]

[0300] In Example 1, the types and amounts of the polymers and crosslinking agents contained in the weakly anchoring liquid crystal aligning agent were changed as shown in Table 7 below. Except for this, the weakly anchoring liquid crystal aligning agent was prepared in the same manner as in Example 1, a liquid crystal alignment film was formed, and an FFS-type liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 7 below.

[0301] [Table 7]

[0302]

[0303] In Table 7, the mass ratio of each component of the liquid crystal aligning agent represents the blending ratio (parts by mass) of each compound relative to a total of 100 parts by mass of the polymer components used in the preparation of the weakly anchoring liquid crystal aligning agent.

[0304] [Example 33, Example 34]

[0305] In Example 1, the types and amounts of the polymers and crosslinking agents contained in the weak-anchoring liquid crystal aligning agent were changed as shown in Table 8 below. Except for this, a weak-anchoring liquid crystal aligning agent was prepared in the same manner as in Example 1, a liquid crystal alignment film was formed, and an FFS-type liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 8 below.

[0306] [Example 35]

[0307] In Example 1, the types and amounts of the polymers and crosslinking agents contained in the weak-anchoring liquid crystal aligning agent were changed as shown in Table 8 below. For the film thickness of the weak-anchoring liquid crystal alignment film on the second substrate, it was changed to 2 μm assuming a protective film (outer coating) on the color filter. Except for this, a liquid crystal aligning agent was prepared in the same manner as in Example 1, a liquid crystal alignment film was formed, and an FFS-type liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 8 below.

[0308] [Comparative Example 9]

[0309] In Example 1, instead of the weak-anchoring liquid crystal aligning agent (AL-1), the liquid crystal aligning agent used when forming the liquid crystal alignment film on the second substrate was set as a strong-anchoring liquid crystal aligning agent (AL-P1), and it was formed in the same manner as the liquid crystal alignment film on the first substrate. Except for this, an FFS-type liquid crystal display element was manufactured and various evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 8 below. In addition, the first substrate and the second substrate were bonded in a manner that the polarization planes were parallel.

[0310] [Table 8]

[0311]

[0312] In Table 8, the mass ratio of each component of the liquid crystal aligning agent represents the blending ratio (parts by mass) of each compound with respect to a total of 100 parts by mass of the polymer components used in the preparation of the liquid crystal aligning agent.

[0313] [Example 36: Friction-Aligned FFS-Type Liquid Crystal Display Element]

[0314] (1) Preparation of Weak-Anchoring Liquid Crystal Aligning Agent

[0315] The polymer (P-33) (40 parts by mass), the polymer (PI-1) (60 parts by mass), the crosslinking agent (AD-2) (5 parts by mass), and the adhesion promoter (AD-3) (1 part by mass) were diluted with NMP and BC to obtain a liquid having a solid content concentration of 4.0% by mass and a solvent composition ratio of NMP:BC = 60:40 (mass ratio). The solution was filtered through a filter with a pore size of 0.2 μm to prepare a weak-anchoring liquid crystal aligning agent (AL-36).

[0316] (2) Fabrication and evaluation of liquid crystal display elements

[0317] Fabrication Figure 1 The FFS type liquid crystal display element 10 shown was subjected to various characteristic evaluations.

[0318] (i) Formation of liquid crystal alignment film by rubbing alignment method

[0319] Using a spin coater, the strong-anchoring liquid crystal aligning agent (AL-R1) prepared in Preparation Example 2 was coated on the electrode formation surface of the first substrate. After heating on a hot plate at 80°C for 1 minute, it was heated in an oven at 230°C with nitrogen replacement in the chamber for 30 minutes to form a coating film with an average film thickness of 100 nm. For the surface of the coating film, a rubbing machine with a roller wound with a rayon cloth was used to perform two rubbing treatments at a roller rotation speed of 1,000 rpm, a stage moving speed of 30 mm / second, and a hair penetration length of 0.3 mm. At this time, the rubbing direction was set parallel to the direction of the double-headed arrow in Figure 2 (b). The coating film subjected to the rubbing alignment treatment was ultrasonically cleaned in ultrapure water for 1 minute, and then dried in an oven at 100°C for 10 minutes to form a strong-anchoring liquid crystal alignment film.

[0320] (ii) Formation of weak-anchoring liquid crystal alignment film

[0321] Using a spin coater, the weak-anchoring liquid crystal aligning agent (AL-36) prepared in (1) above was coated on one surface of the second substrate. After heating on a hot plate at 80°C for 1 minute, it was heated in an oven at 230°C with nitrogen replacement in the chamber for 30 minutes to form a weak-anchoring liquid crystal alignment film with an average film thickness of 100 nm.

[0322] (iii) Fabrication of FFS type liquid crystal display element

[0323] Using the pair of substrates produced in (i) and (ii) above, an FFS type liquid crystal display element was fabricated in the same manner as in Example 1.

[0324] (iv) Evaluation of liquid crystal alignment property

[0325] For the liquid crystal display element manufactured in the above (iii), the evaluation of the liquid crystal alignment property was carried out in the same manner as in Example 1. As a result, the evaluation was "good" in this example.

[0326] (v) Evaluation of brightness

[0327] For the liquid crystal display element manufactured in the above (iii), the evaluation of brightness was carried out in the same manner as in Example 1. As a result, the evaluation was "excellent" in this example.

[0328] (vi) Evaluation of adhesion

[0329] Using the weak anchoring liquid crystal aligning agent (AL-36) prepared in the above (1) and the strong anchoring liquid crystal aligning agent (AL-R1) prepared in Preparation Example 2, the evaluation of adhesion was carried out in the same manner as in Example 1. As a result, the evaluation was "excellent" in this example.

[0330] [Example 37, Example 38, Comparative Example 10, Comparative Example 11]

[0331] In Example 36, the types and amounts of the polymer and the crosslinking agent contained in the weak anchoring liquid crystal aligning agent were changed as shown in Table 9 below. Except for this, a liquid crystal aligning agent was prepared in the same manner as in Example 36, a liquid crystal alignment film was formed, and an FFS type liquid crystal display element was manufactured and various evaluations were carried out. The evaluation results are shown in Table 9 below.

[0332] [Comparative Example 12]

[0333] In Example 36, instead of the weak anchoring liquid crystal aligning agent (AL-36), the liquid crystal aligning agent used when forming the liquid crystal alignment film on the second substrate was set as the strong anchoring liquid crystal aligning agent (AL-R1), and it was formed in the same manner as the liquid crystal alignment film on the first substrate. Except for this, an FFS type liquid crystal display element was manufactured and various evaluations were carried out in the same manner as in Example 36. The evaluation results are shown in Table 9 below. In addition, the first substrate and the second substrate were bonded in a manner where the rubbing directions were opposite and parallel (antiparallel).

[0334] [Table 9]

[0335]

[0336] In Table 9, the mass ratio of each component of the liquid crystal aligning agent represents the blending ratio (parts by mass) of each compound relative to a total of 100 parts by mass of the polymer component used in the preparation of the liquid crystal aligning agent.

[0337] As shown in Tables 7 to 9, the evaluation of the liquid crystal alignment, brightness, and adhesion in Examples 1 to 38 was "excellent" or "good". In contrast, in Comparative Examples 1 to 9 using a liquid crystal aligning agent that does not contain the polymer (P) or does not satisfy any of the above requirements (I) to (III), the evaluation of at least any one of the liquid crystal alignment, brightness, and adhesion was "poor".

[0338] When considering these results, it is considered that in Examples 1 to 38, by using a liquid crystal aligning agent containing the polymer (P), the glass transition temperature of the polymer is sufficiently low with respect to the operating temperature range of the liquid crystal display element, and thus a weak anchoring property is exhibited. It is considered that at a temperature higher than the glass transition temperature of the polymer, the movement of the polymer molecular chains becomes active, and the liquid crystal molecules are not restricted by the liquid crystal alignment film and become a state with high degrees of freedom (sliding interface). Therefore, it is considered that the liquid crystal molecules can quickly and flexibly change the alignment direction in response to external stimuli. As a result, characteristics derived from weak anchoring (zero surface anchoring) such as low voltage driving, increased brightness (increased transmittance directly above the electrode with a weak electric field), and increased response speed during rise are observed in the liquid crystal element.

[0339] Furthermore, in Examples 1 to 38, by using a liquid crystal aligning agent that satisfies at least any one of the above requirements (I) to (III), the composition has a thermally crosslinkable reactivity. Therefore, it is considered that a liquid crystal alignment film having excellent mechanical strength and liquid crystal resistance (inhibiting the dissolution of the polymer into the liquid crystal layer) is obtained by thermal curing.

[0340] In addition, in Examples 1 to 38, since the polymer (P) has a sufficient amount of the structural unit (A), it is considered that although the glass transition temperature of the polymer is low, the increase in hydrophobicity is suppressed. Therefore, the surface free energy of the liquid crystal alignment film is high, and the intermolecular interaction or affinity with the sealant component formed on the liquid crystal alignment film is improved. As a result, excellent adhesion is exhibited. In addition, since the hydrophobicity of the polymer is not too high, it is considered that the liquid crystal is easily horizontally aligned, showing good liquid crystal alignment properties.

[0341] In contrast, in Comparative Examples 1, 2, 5, 10, and 11, the polymer contained in the liquid crystal aligning agent does not have the structural unit (A), or the content ratio of the structural unit (A) is low, and the adhesion was evaluated as "poor". It is speculated that due to the high hydrophobicity of the polymer, the surface free energy of the liquid crystal alignment film is low, so the intermolecular interaction or affinity with the sealant component becomes small, and peeling easily occurs at the interface between the sealant and the liquid crystal alignment film.

[0342] In Comparative Examples 3 to 4, Comparative Example 6, and Comparative Example 7, the polymer contained in the liquid crystal aligning agent does not have the structural unit (A), or the content ratio of the structural unit (A) is low, and the liquid crystal alignment property and brightness are both evaluated as "poor". It is considered that this is because the glass transition temperature of the polymer is high, so the weak anchoring property is not exhibited. Furthermore, it is speculated that when the polymer has a long-chain alkyl group in the side chain, the horizontal alignment of the liquid crystal is unstable and easily disturbs the uniform alignment of the liquid crystal.

[0343] In Comparative Example 8, the liquid crystal aligning agent does not satisfy any of the above-mentioned requirements (I) to (III), and the liquid crystal alignment property, brightness, and adhesion are all evaluated as "poor". It is considered that this is because the polymer in the liquid crystal alignment film is not crosslinked, so the mechanical strength of the liquid crystal alignment film is low, and in addition, the polymer is easily dissolved in the liquid crystal layer.

[0344] In Comparative Example 9 and Comparative Example 12, in both the first substrate and the second substrate of the liquid crystal element, a strong anchoring liquid crystal alignment film is provided, and the liquid crystal alignment property and adhesion are evaluated as "good" or "excellent", but the brightness is evaluated as "poor". This is because the weak anchoring property is not exhibited in the existing strong anchoring liquid crystal alignment film.

[0345] From the above results, it is clear that a liquid crystal element having excellent liquid crystal alignment property and brightness characteristics and a liquid crystal alignment film having excellent adhesion can be obtained by using a liquid crystal aligning agent containing the polymer (P) and satisfying at least one of the above-mentioned requirements (I) to (III).

Claims

1. A liquid crystal aligning agent comprising a polymer (P) comprising a structural unit (A) represented by the following formula (1): In formula (1), a is an integer greater than 1; R 1 is a hydrogen atom or a monovalent organic group; R 3 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms; X 1 -O-, -S-, * 1 -C(=O)-O- or * 1 -OC(=O)-;"* 1 " indicates that the 2 The bond of In R 3 In the case of a hydrogen atom, 3 Bonded X 1 -O-, -S- or * 1 -C(=O)-O-; when a is 1 and R 3 is a hydrogen atom, or a is 1, R 1 is a monovalent organic radical and R 3 is methyl, or a is 2, R 1 is a monovalent organic radical and R 3 When R is a hydrogen atom, 2 is an alkanediyl group having 4 to 16 carbon atoms, and in other cases is an alkanediyl group having 2 to 8 carbon atoms; wherein R to which *-COO- in formula (1) is bonded is 2 In the adjacent X 1 When a is 2 or more, the two oxygen atoms are linked via two or more carbon atoms, wherein "*" represents a bond to a carbon atom constituting the main chain; when a is 2 or more, multiple R 2 Same or different, multiple X 1 Same or different, The content ratio of the structural unit (A) is 35% by mass or more relative to all the structural units of the polymer (P), The polymer (P) has at least one crosslinking group selected from the group consisting of a hydroxyl group, a protected hydroxyl group, a protected amino group, a thiol group, a protected thiol group, a carboxyl group, a protected carboxyl group, an anhydride group, an oxirane group, a protected oxirane group, an oxetane group, and a protected isocyanate group, and The liquid crystal alignment agent satisfies at least one of the following requirements (I), (II) and (III); Requirement (I): The polymer (P) has a first functional group and a second functional group, wherein the first functional group is any one of the crosslinking groups, and the second functional group is a functional group among the crosslinking groups or a functional group different from the crosslinking group that can react with the first functional group to form a bond, and is different from the first functional group; Requirement (II): The polymer (P) has a self-crosslinking functional group as the crosslinking group; Requirement (III): further comprising a compound (D) having two or more functional groups capable of reacting with the crosslinking group of the polymer (P) to form a bond, and different from the polymer (P).

2. The liquid crystal alignment agent according to claim 1, wherein the polymer (P) further comprises a structural unit (B) having the crosslinking group, wherein: The structural unit (A) is excluded. 3 . The liquid crystal alignment agent according to claim 1 , wherein the glass transition temperature of the polymer (P) is not less than −100° C. and not more than 20° C. 4 . The liquid crystal aligning agent according to claim 1 , wherein a homopolymer of the monomer providing the structural unit (A) has a glass transition temperature of −100° C. or higher and 0° C. or lower.

5. The liquid crystal alignment agent according to claim 1, comprising R in the formula (1): 3 As the structural unit (A), a structural unit which is a hydrogen atom. 6 . The liquid crystal alignment agent according to claim 1 , further comprising at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester and polyimide. The liquid crystal alignment agent according to claim 1 , used for forming a weak anchor liquid crystal alignment film. 8 . A weak anchor liquid crystal alignment film, formed using the liquid crystal alignment agent according to claim 1 . 9 . A liquid crystal element comprising the weakly anchored liquid crystal alignment film according to claim 8 .

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