Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal element and manufacturing method thereof

Abstract

The invention provides a liquid crystal aligning agent, a liquid crystal aligning film, a liquid crystal element and a manufacturing method thereof. The liquid crystal aligning agent can realize low-voltage driving of the liquid crystal element, can form a liquid crystal aligning film with excellent sealing performance and is excellent in coating performance. A liquid crystal aligning agent contains an addition polymer [P] containing: a structural unit [A] having a hydroxyl group bonded to a carbon atom in a chain structure or in an aliphatic ring (excluding a carbon atom in a carbonyl group and a carbon atom constituting a main chain of the polymer); and a structural unit [B] which has a partial structure represented by formula (1) and is different from the structural unit [A].

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal element, and a manufacturing method thereof. BACKGROUND

[0002] In a liquid crystal element, in general, the initial alignment of liquid crystal molecules is prescribed by the anchoring of liquid crystal molecules by a liquid crystal alignment film. In recent years, in a horizontal alignment mode liquid crystal element such as an In-Plane Switching (IPS) type or a Fringe Field Switching (FFS) type, various liquid crystal elements have been proposed in which a liquid crystal alignment film having a strong anchoring energy (hereinafter, also referred to as "strong anchoring liquid crystal alignment film") is formed on one of a pair of substrates, and a liquid crystal alignment film having no anchoring energy or a very small anchoring energy (hereinafter, also referred to as "weak anchoring liquid crystal alignment film") is formed on the other substrate. In a liquid crystal element utilizing a weak anchoring state, compared to a general liquid crystal element in which a strong anchoring liquid crystal alignment film is formed on both substrates, improvement in luminance and contrast ratio or low voltage driving, high speed response (high speed rise), and the like can be achieved, and further improvement is expected. In addition, "weak anchoring" is also referred to as "zero surface anchoring".

[0003] For example, in Patent Literature 1, it is disclosed that a liquid crystal cell is manufactured by forming a zero surface anchoring film on a first substrate by a method including a step of providing energy sufficient for a radical polymerizable compound to undergo a polymerization reaction in a state in which a liquid crystal composition containing a liquid crystal and the radical polymerizable compound is in contact with a radical generating film, and forming a liquid crystal alignment film on a second substrate using a known liquid crystal alignment agent.

[0004] [Patent Literature]

[0005] [Patent Literature]

[0006] [Patent Literature 1] International Publication No. 2019 / 004433 SUMMARY

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

[0008] In the technology described in Patent Literature 1, when a weak anchoring liquid crystal alignment film is produced, a process in which a liquid crystal composition containing a liquid crystal and a radical polymerizable compound is brought into contact with a radical generating film formed on a first substrate, and energy sufficient for the radical polymerizable compound to undergo a polymerization reaction is provided in this state is required, and it cannot be said that the production efficiency is good. Therefore, although it is a simple production method such as inkjet coating, it is desired that a liquid crystal element capable of achieving low voltage driving derived from a weak anchoring state and exhibiting good liquid crystal alignment properties can be obtained.

[0009] In addition, in recent years, in addition to mobile uses represented by smartphones or tablet personal computers (PCs), in large televisions or PC monitors, from the viewpoint of design or the viewpoint of miniaturization of display devices, narrow frame formation is being implemented. As one of the methods for implementing narrow frame formation, a method is known in which a liquid crystal alignment film is formed over the entire surface of a substrate, and then a sealant is applied to the liquid crystal alignment film to adhere 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 easily decreases and peeling of the substrates easily occurs due to the action of external force or the like.

[0010] However, it is difficult to achieve low-voltage driving while taking into account inkjet coatability and adhesion, and there is room for further improvement in liquid crystal alignment agents and liquid crystal elements.

[0011] The present application was made in view of the problems described above, and a main object thereof is to provide a liquid crystal alignment agent that can form a liquid crystal alignment film having excellent adhesion and excellent coatability, and a liquid crystal element that can be driven at low voltage.

[0012] [Technical means for solving the problem]

[0013] By the present application, the following liquid crystal alignment agent, liquid crystal alignment film, liquid crystal element, and method for manufacturing the same can be provided.

[0014] 〔1〕 A liquid crystal alignment agent containing an addition polymer [P] comprising: a structural unit [A] having a hydroxyl group bonded to a carbon atom in a chain structure or within an aliphatic ring (wherein a carbon atom in a carbonyl group and a carbon atom constituting a main chain of the polymer are excluded); and a structural unit [B] having a partial structure represented by the following formula (1) and being different from the structural unit [A].

[0015] * 1 -CO-O-R 1 …(1)

[0016] (In formula (1), R 1 is a monovalent chain hydrocarbon group having a branched structure; and 1 represents a bonding bond to a carbon atom constituting a main chain of the polymer)

[0017] 〔2〕 A liquid crystal alignment film formed using the liquid crystal alignment agent described in the above item 〔1〕.

[0018] 〔3〕 A liquid crystal element comprising the liquid crystal alignment film described in the above item 〔2〕.

[0019] 〔4〕 A method for manufacturing a liquid crystal element including a pair of substrates including a first substrate and a second substrate, and a liquid crystal layer disposed between the pair of substrates, the method for manufacturing a liquid crystal element including a step of forming a liquid crystal alignment film on a surface of one of the pair of substrates by applying a liquid crystal alignment agent according to the above-mentioned item 1.

[0020] [Effects of the Invention]

[0021] The liquid crystal alignment agent according to the present application can achieve low-voltage driving of a liquid crystal element, and can form a liquid crystal alignment film having excellent close contact. In addition, the liquid crystal alignment agent according to the present application has excellent applicability. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic structural view of a FFS-type liquid crystal display element.

[0023] Figure 2 (a) of FIG. 1, Figure 2 (b) of FIG. 1 is a plan view for manufacturing a top electrode of a liquid crystal display element. Figure 2 (a) of FIG. 2 is a plan view of a top electrode, Figure 2 (b) of FIG. 2 is a partially enlarged view of a top electrode.

[0024] Figure 3 is a view showing four-system drive electrodes.

[0025] BRIEF DESCRIPTION OF DRAWINGS

[0026] 10: liquid crystal element

[0027] 11: first substrate

[0028] 12: second substrate

[0029] 13: liquid crystal layer

[0030] 14: common electrode

[0031] 15: insulating film

[0032] 16: pixel electrode

[0033] 17: color filter

[0034] 18: overcoat film

[0035] 19: slit

[0036] 21, 22: liquid crystal alignment film

[0037] 23, 24: polarizing plate

[0038] 25: liquid crystal molecule

[0039] C1: portion enclosed by dotted line

[0040] d1: line width of electrode

[0041] d2: distance between electrodes DETAILED DESCRIPTION

[0042] Liquid crystal alignment agent

[0043] The liquid crystal alignment agent of the present disclosure contains an addition polymer (hereinafter, also referred to as "addition polymer [P]") containing two structural units (hereinafter, also referred to as "structural unit [A]" and "structural unit [B]", respectively) having specific structures. Hereinafter, each component contained in the liquid crystal alignment agent of the present disclosure and other components optionally arbitrarily blended will be described. Furthermore, as for each component, unless specifically mentioned, one kind can be used alone, or two or more kinds can be used in combination. In addition, in the present specification, the numerical range written using "~" is intended to include the numerical values written before and after the "~" as lower limit values and upper limit values.

[0044] Here, in the present specification, "hydrocarbon group" is intended to include chain hydrocarbon group, alicyclic hydrocarbon group, and aromatic hydrocarbon group. The "chain hydrocarbon group" means straight chain hydrocarbon group and branched chain hydrocarbon group which do not contain cyclic structure and include only chain structure. Among them, the chain hydrocarbon group can be saturated or unsaturated. The "alicyclic hydrocarbon group" means a hydrocarbon group which contains only alicyclic hydrocarbon as a cyclic structure and does not contain aromatic ring structure. Among them, the alicyclic hydrocarbon group does not need to include only alicyclic hydrocarbon structure, and also includes a group having chain structure in a part thereof. The "aromatic hydrocarbon group" means a hydrocarbon group which contains aromatic ring structure as a cyclic structure. Among them, the aromatic hydrocarbon group does not need to include only aromatic ring structure, and can contain chain structure or alicyclic hydrocarbon structure in a part thereof. The "aromatic ring" means aromatic hydrocarbon ring and aromatic heterocyclic ring. The "organic group" means a group obtained by removing arbitrary hydrogen atom from a compound containing carbon (i.e., organic compound).

[0045] The "main chain" of a polymer refers to the "main stem" of a chain of atoms that is the longest in the polymer. The "main stem" portion can allow for inclusion of ring structures. For example, "having a particular structure in the main chain" means that the particular structure forms a portion of the main chain. The "side chain" refers to a portion that branches from the "main stem" portion of the polymer. The "structural unit" refers to a unit that forms a major portion of the main chain structure and is at least two or more units in the main chain structure. Typically, the structural unit is a monomeric unit. Among them, the structural unit obtained by reacting a monomeric unit having a reactive group with a compound having a functional group capable of reacting with the reactive group is also included in the "structural unit". The "(meth)acrylic group" is a term including an acrylic group and a methacrylic group, and the "(meth)acryloyl" is a term including an acryloyl group and a methacryloyl group.

[0046] <Addition polymer [P]>

[0047] The addition polymer [P] contained in the liquid crystal alignment agent of the present disclosure is a polymer including a structural unit derived from a monomeric unit having a polymerizable unsaturated carbon-carbon bond, and is not particularly limited as long as it includes the structural unit [A] and the structural unit [B]. That is, as long as one or more of the monomeric units that constitute the addition polymer [P] is a monomeric unit that provides the structural unit [A], and one or more of the monomeric units that constitute the addition polymer [P] is a monomeric unit that provides the structural unit [B]. As the addition polymer [P], for example, a polymer having a main skeleton of a (meth)acrylic polymer, a (meth)acrylic-styrene copolymer, a (meth)acrylic-maleimide copolymer, a (meth)acrylic-styrene-maleimide copolymer, a (meth)acrylic-vinyl ether-maleic anhydride copolymer, and a (meth)acrylic-styrene-maleimide copolymer, and the like, and including the structural unit [A] and the structural unit [B] can be exemplified.

[0048] (structural unit [A])

[0049] The structural unit [A] has a hydroxyl group bonded to a carbon atom in a chain structure or within an aliphatic ring (wherein the carbon atom in a carbonyl group and the carbon atom constituting the main chain of the polymer are excluded). The structural unit [A] can also have a carbonyl group or an aromatic ring, as long as the carbon atom to which the hydroxyl group is bonded is a carbon atom in a chain structure or within an aliphatic ring (wherein the carbon atom in a carbonyl group and the carbon atom constituting the main chain of the polymer are excluded). In addition, the carbon atom to which the hydroxyl group is bonded can be directly bonded to the main chain of the addition polymer [P], or can be bonded to the main chain of the addition polymer [P] via a divalent organic group.

[0050] As the chain structure including a carbon atom to which a hydroxyl group is bonded, for example, a chain hydrocarbon group, a chain hydrocarbon group including -O-, -CO-, -COO-, -NR1R2- (wherein R1and R2are each independently a hydrogen atom or a hydrocarbon group), -SiR3R4R5- (wherein R3, R4, and R5are each independently a hydrocarbon group), -SnR6R7R8- (wherein R6, R7, and R8are each independently a hydrocarbon group), -BR9R10- (wherein R9and R10are each independently a hydrocarbon group), -P(=O)(OR11)2- (wherein R11is a hydrocarbon group), -P(=O)(NR12)2- (wherein R12is a hydrocarbon group), -P(=O)(NR13)(OR14)- (wherein R13and R14are each independently a hydrocarbon group), -SiR15R16R17- (wherein R15, R16, and R17are each independently a hydrocarbon group), -SnR18R19R20- (wherein R18, R19, and R20are each independently a hydrocarbon group), -BR21R22- (wherein R21and R22are each independently a hydrocarbon group), -P(=O)(OR23)2- (wherein R23is a hydrocarbon group), -P(=O)(NR24)2- (wherein R24is a hydrocarbon group), -P(=O)(NR25)(OR26)- (wherein R25and R26are each independently a hydrocarbon group), and the like, in which a carbon-carbon bond in the chain hydrocarbon group is included, can be exemplified.11 -or-CO-NR 11 - and some of these groups are formed by replacing hydrogen atoms with halogen atoms (fluorine, chlorine, bromine, iodine, etc.).

[0051] Examples of aliphatic rings containing carbon atoms bonded by hydroxyl groups include aliphatic hydrocarbon rings, aliphatic heterocycles, and rings in which some hydrogen atoms are replaced by halogen atoms.

[0052] R 11 It consists of hydrogen atoms or monovalent chain hydrocarbon groups with 1 to 10 carbon atoms.

[0053] The hydroxyl group in structural unit [A] is preferably a carbon atom bonded to the chain structure (excluding the carbon atom in the carbonyl group and the carbon atom constituting the main chain of the polymer), and more preferably exists in the form of a hydroxyl group constituting a hydroxyalkyl group. The structural unit [A] may have one or more hydroxyl groups, preferably one or two, and more preferably one.

[0054] As a preferred specific example of structural unit [A], a structural unit having a partial structure represented by the following formula (2) can be listed.

[0055] * 2 -CO-OA 1 -C(B 1 (B) 2 )-OH…(2)

[0056] (In equation (2), A) 1 It is a single bond or a divalent organic group; B 1 and B 2 Each of these can be independently a hydrogen atom, a halogen atom, or a monovalent organic group; "* 2 "" indicates the bonds formed with the carbon atoms that make up the polymer backbone.

[0057] In the above equation (2), A is... 1 The divalent organic groups represented can be listed as: substituted or unsubstituted divalent hydrocarbon groups, and carbon-carbon bonds in substituted or unsubstituted divalent hydrocarbon groups containing -O-, -CO-, -COO-, or -NR. 12 -or-CO-NR 12 - Divalent groups, etc. Examples of divalent hydrocarbon groups include: divalent chain hydrocarbon groups with 1 to 20 carbon atoms, divalent alicyclic hydrocarbon groups with 3 to 12 carbon atoms, and divalent aromatic hydrocarbon groups with 6 to 10 carbon atoms. Examples of substituents introduced into divalent hydrocarbon groups include hydroxyl groups and halogen atoms. From the perspective of low-voltage driven conversion, A 1A divalent organic group other than a single bond or an aromatic ring, more preferably a substituted or unsubstituted divalent chain hydrocarbon group, or a divalent group containing -O- or -CO- between carbon-carbon bonds in a substituted or unsubstituted divalent chain hydrocarbon group, further preferably an alkanediyl group, further more preferably an alkanediyl group having 1 to 5 carbons, particularly preferably a linear alkanediyl group having 1 to 5 carbons.

[0058] R 12 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbons.

[0059] as B 1 and B 2 represented by the following formulae (1-1) to (1-13), respectively. 13 - or -CO-NR 13 - containing group, etc. As the monovalent hydrocarbon group, a monovalent chain hydrocarbon group having 1 to 20 carbons, a monovalent alicyclic hydrocarbon group having 3 to 12 carbons, and a monovalent aromatic hydrocarbon group having 6 to 10 carbons, etc. can be exemplified. As the substituent introduced into the monovalent hydrocarbon group, a hydroxyl group, a halogen atom, etc. can be exemplified. As B 1 and B 2 , a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group, or a monovalent group containing -O- between carbon-carbon bonds in a substituted or unsubstituted monovalent hydrocarbon group, more preferably a hydrogen atom, a monovalent hydrocarbon group, a monovalent halogenated hydrocarbon group, or a monovalent group containing -O- between carbon-carbon bonds in a monovalent hydrocarbon group or a monovalent halogenated hydrocarbon group, further preferably a hydrogen atom, an alkyl group having 1 to 5 carbons, or a halogenated alkyl group having 1 to 5 carbons, particularly preferably a hydrogen atom.

[0060] R 13 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbons.

[0061] As a specific example of the monomer providing the structural unit [A], for example, a compound represented by the following formulae (1-1) to (1-13), respectively, can be exemplified.

[0062] [Chemical Formula 1]

[0063]

[0064] (in formulae (1-1) to (1-13), R is a hydrogen atom or a methyl group;

[0065] in formula (1-13), n is an integer of 2 to 10)

[0066] As the monomer providing the structural unit [A], from the viewpoint of improvement in low-voltage driving, the compounds represented by the formula (1-1) to formula (1-8), formula (1-12), and formula (1-13) are preferable, the compounds represented by the formula (1-1) to formula (1-8), and formula (1-12) are more preferable, and the compounds represented by the formula (1-1) to formula (1-7) are further preferable.

[0067] From the viewpoint of optimization of adhesiveness and coatability, the content ratio of the structural unit [A] in the addition polymer [P] is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 15 mol% or more, with respect to all the structural units constituting the addition polymer [P]. In addition, from the viewpoint of optimization of low-voltage driving and coatability, the content ratio of the structural unit [A] is preferably 70 mol% or less, more preferably 60 mol% or less, and further preferably 50 mol% or less, with respect to all the structural units constituting the addition polymer [P].

[0068] (structural unit [B])

[0069] The structural unit [B] has a partial structure represented by the following formula (1) and is different from the structural unit [A].

[0070] * 1 -CO-O-R 1 …(1)

[0071] (In formula (1), R 1 is a monovalent chain hydrocarbon group having a branched structure; and “ 1 ” represents a bonding bond to a carbon atom constituting a main chain of a polymer)

[0072] The structural unit [B] is different from the structural unit [A] in that it does not have a hydroxyl group bonded to a carbon atom in a chain structure or within an aliphatic ring. That is, even if it has the partial structure represented by the formula (1), a structural unit having the hydroxyl group belongs to the structural unit [A].

[0073] In the formula (1), as the monovalent chain hydrocarbon group having a branched structure represented by R 1 , a chain hydrocarbon group having a branched structure having a carbon number of 3 to 50, and the like can be exemplified. R 1 is preferably a branched alkyl group having a carbon number of 3 to 50. The carbon number of the branched alkyl group is more preferably 4 or more, further preferably 6 or more, and particularly preferably 8 or more. In addition, the carbon number of the branched alkyl group is more preferably 40 or less, further preferably 30 or less, further more preferably 20 or less, and particularly preferably 15 or less.

[0074] From the viewpoint of optimization of adhesiveness and the viewpoint of suppression of elution of impurities into a liquid crystal, R1 The monovalent chain hydrocarbon group having a branched structure is preferably a group that does not dissociate from the partial structure represented by the formula (1) due to heat (mainly heat at the time of film formation). Specifically, it is preferable that it does not dissociate due to heat at 150°C, more preferable that it does not dissociate due to heat at 200°C, and further preferable that it does not dissociate due to heat at 250°C.

[0075] In R 1 The number of branched structures that the monovalent chain hydrocarbon group has is not particularly limited, provided that there is at least one or more branched structures in the monovalent chain hydrocarbon group. In addition, the carbon atom at the branching point can be either a tertiary carbon atom or a quaternary carbon atom, and is preferably a tertiary carbon atom. Furthermore, the portion of the monovalent chain hydrocarbon group having a branched structure is not particularly limited, and from the viewpoint of optimizing the adhesiveness, it is preferable that it is branched at least at the carbon atom (alpha carbon) adjacent to the ester group (the group "- 1 -CO-O- " in the formula (1)), or further branched at the adjacent carbon atom (beta carbon), and more preferable that it is branched at the carbon atom (alpha carbon) adjacent to the ester group.

[0076] As the monomer that provides the structural unit [B], a (meth)acrylic acid compound containing a monovalent chain hydrocarbon group having a branched structure is preferable. As specific examples of the monomer that provides the structural unit [B], for example, the compounds represented by the following formulas (2-1) to (2-12) can be listed.

[0077] [Chem. 2]

[0078]

[0079] (In the formulas (2-1) to (2-12), R is a hydrogen atom or a methyl group)

[0080] As the monomer that provides the structural unit [B], from the viewpoint of optimizing the adhesiveness, the compounds represented by the formulas (2-1), (2-3), (2-5) to (2-8), (2-11), and (2-12) are preferable, and the compounds represented by the formulas (2-5) to (2-8) are more preferable.

[0081] From the viewpoint of optimizing the low voltage driving and the coatability, the proportion of the structural unit [B] in the addition polymer [P] is preferably 15 mol% or more, more preferably 20 mol% or more, and further preferably 25 mol% or more, with respect to all the structural units that constitute the addition polymer [P]. From the viewpoint of optimizing the adhesiveness and the coatability, the proportion of the structural unit [B] is preferably 90 mol% or less, more preferably 80 mol% or less, and further preferably 70 mol% or less, with respect to all the structural units that constitute the addition polymer [P].

[0082] (structural unit [C])

[0083] The addition polymer [P] can be an addition polymer containing only the structural unit [A] and the structural unit [B] as the structural units. From the viewpoint of further optimizing the close contact property, it is preferable that the addition polymer [P] contain, in addition to the structural unit [A] and the structural unit [B], a structural unit having a structure represented by the following formula (3) and being different from the structural unit [A] and the structural unit [B] (hereinafter, also referred to as "structural unit [C]").

[0084] * 3 -CO-O-R 2 …(3)

[0085] (In formula (3), R 2 is a monovalent linear hydrocarbon group; "— " represents a bond to a carbon atom constituting the main chain of the polymer) 3

[0086] The structural unit [C] is different from the structural unit [A] in that it does not have a hydroxyl group bonded to a carbon atom in a chain structure or within an aliphatic ring, and is different from the structural unit [B] in that it does not have the partial structure represented by the formula (1). That is, even if it has the partial structure represented by the formula (3), a structural unit having the hydroxyl group belongs to the structural unit [A], and a structural unit not having the hydroxyl group but having the partial structure represented by the formula (1) belongs to the structural unit [B]. For example, a structural unit derived from a monomer represented by the formula (2-12) has the partial structure represented by the formula (3), but also has the partial structure represented by the formula (1) at the same time, and thus belongs to the structural unit [B].

[0087] In the formula (3), as the monovalent linear hydrocarbon group represented by R 2 , a linear alkyl group having 1 to 50 carbons can be exemplified. R 2 is preferably a linear alkyl group having 1 to 20 carbons, and more preferably a linear alkyl group having 1 to 10 carbons.

[0088] As specific examples of the monomer providing the structural unit [C], for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-eicosyl (meth)acrylate, and the like can be exemplified.

[0089] ​In the case where the addition polymer [P] contains the structural unit [C], the proportion of the structural unit [C] is preferably 10 mol% or more, more preferably 15 mol% or more, and further preferably 20 mol% or more, relative to all the structural units constituting the addition polymer [P], from the viewpoint of optimization of adhesiveness. In addition, the proportion of the structural unit [C] is preferably 60 mol% or less, more preferably 50 mol% or less, and further preferably 40 mol% or less, relative to all the structural units constituting the addition polymer [P], from the viewpoint of optimization of adhesiveness and coatability.

[0090] (Other structural unit)

[0091] The addition polymer [P] can also contain a structural unit different from the structural unit [A] and the structural unit [B], and further different from the structural unit [C] (hereinafter, also referred to as "other structural unit"). As the other structural unit, any structural unit can be used as long as it does not have a hydroxyl group bonded to a carbon atom in a chain structure or in an aliphatic ring, and does not have the partial structure represented by the formula (1) and the partial structure represented by the formula (3). As a monomer (hereinafter, also referred to as "other monomer") that provides the other structural unit, (meth)acrylic compounds, aromatic vinyl compounds, conjugated diene compounds, maleimide compounds, vinyl ether compounds, maleic amide compounds, and the like can be exemplified.

[0092] As the (meth)acrylic compound, unsaturated carboxylic acids such as (meth)acrylic acid, maleic acid, fumaric acid, and the like; unsaturated carboxylic acid esters such as (meth)acrylic acid cycloalkyl ester, benzyl (meth)acrylate, trimethoxysilylpropyl (meth)acrylate, glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 4-hydroxybutyl glycidyl ether, 3-(meth)acryloyloxypropyl trimethoxysilane, 3-(meth)acryloyloxypropyl triethoxysilane, 6-(meth)acryloyloxyhexyl trimethoxysilane, 3-(meth)acryloyloxypropyl methyl dimethoxysilane, and 3-(meth)acryloyloxypropyl methyl diethoxysilane, and the like can be exemplified.

[0093] As the aromatic vinyl compound, styrene, methylstyrene, divinylbenzene, p-vinyltrimethoxysilane, 4-(glycidyloxymethyl)styrene, and vinylbenzoic acid, and the like can be exemplified. As the conjugated diene compound, 1,3-butadiene, 2-methyl-1,3-butadiene, and the like can be exemplified. As the maleimide compound, N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(4-glycidyloxyphenyl)maleimide, N-(4-glycidyloxymethylphenyl)maleimide, N-glycidylmaleimide, N-(4-carboxyphenyl)maleimide, N-(4-t-butoxycarbonylphenyl)maleimide, and the like can be exemplified. As the vinyl ether compound, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, cyclohexyl vinyl ether, 1,4-butanediol divinyl ether, diethylene glycol divinyl ether, and the like can be exemplified. As the maleamide compound, N,N'-dimethylmaleamide, N,N'-diisopropylmaleamide, N,N'-diisobutylmaleamide, N,N'-diphenylmaleamide, and the like can be exemplified.

[0094] Further, as other monomer, a compound other than the monomer providing the structural unit [A], the monomer providing the structural unit [B], and the monomer providing the structural unit [C], which is an unsaturated monomer having a photo-alignment group (for example, a cinnamate structure or a coumarin structure, an azobenzene structure), an alkyl group having a carbon number of 4 to 30, a halogenated alkyl group having a carbon number of 4 to 30, an alkoxy group having a carbon number of 4 to 30, a halogenated alkoxy group having a carbon number of 4 to 30, one or more of a benzene ring and a cyclohexane ring, and the like, which are linked to two or more via a single bond or a linking group, or a vertical alignment group such as a steroid skeleton, can also be used.

[0095] In the case where the addition polymer [P] contains other structural units, the proportion of the other structural units can be appropriately selected within a range not impairing the effects of the present disclosure. Specifically, it is preferably 30 mol% or less, more preferably 20 mol% or less, and further preferably 10 mol% or less, with respect to all the structural units constituting the addition polymer [P].

[0096] (Synthesis of the addition polymer [P])

[0097] The addition polymer [P] is a polymer obtained by addition polymerization, and the details of the synthesis method are not particularly limited. The addition polymer [P] can be obtained, for example, by polymerizing a monomer in the presence of a polymerization initiator. As the polymerization initiator to be used, a radical polymerization initiator can be preferably used, and as specific examples thereof, azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and the like can be exemplified. The use ratio of the polymerization initiator is preferably set to 0.01 parts by mass to 30 parts by mass with respect to 100 parts by mass of the total amount of the monomers used in the reaction.

[0098] The polymerization reaction is preferably performed in an organic solvent. As the organic solvent to be used in the reaction, alcohols, ethers, ketones, amides, esters, hydrocarbon compounds, and the like can be exemplified, and diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether acetate, and the like are preferable. The reaction temperature is preferably set to 30°C to 120°C, and the reaction time is preferably set to 1 hour to 36 hours. The amount of the organic solvent used (a) is preferably set to an amount such that the total amount of the monomers used in the reaction (b) becomes 0.1% by mass to 60% by mass with respect to the total amount of the reaction solution (a+b). For the reaction solution in which the polymer is dissolved, the addition polymer [P] contained in the reaction solution can be separated and used for the production of the liquid crystal alignment agent, for example, by a known separation method such as a method in which the reaction solution is injected into a large amount of a poor solvent and the obtained precipitate is dried under reduced pressure, a method in which the reaction solution is removed by distillation under reduced pressure using an evaporator, or the like.

[0099] Further, in the case of synthesizing an addition polymer having a functional group such as a vertical alignment group or a photoinitiator group in the side chain, in addition to a method in which a monomer having a functional group is used for polymerization, an addition polymer having an epoxy group in the side chain can be synthesized by a method in which a monomer containing an epoxy group is used in at least a part of the raw materials, and then an addition polymer having a functional group in the side chain is synthesized by a method in which a carboxylic acid having a functional group is reacted.

[0100] The weight average molecular weight (Mw) of the addition polymer [P] determined by gel permeation chromatography (GPC) in terms of polystyrene is preferably 250 to 500,000, and more preferably 500 to 100,000. In addition, the molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) determined by GPC is preferably 8 or less, and more preferably 6 or less.

[0101] The content ratio of the addition polymer [P] in the liquid crystal alignment agent of the present disclosure is preferably 3% by mass or more, more preferably 5% by mass or more, and further preferably 10% by mass or more, and particularly preferably 15% by mass or more, relative to the total amount of solid components (components other than the solvent of the liquid crystal alignment agent) contained in the liquid crystal alignment agent, from the viewpoint of achieving stable low-voltage driving.

[0102] <Other components>

[0103] The liquid crystal alignment agent of the present disclosure can contain, in addition to the addition polymer [P], an ingredient (hereinafter, also referred to as "other component") different from the addition polymer [P], as necessary. As the other component, a polymer (hereinafter, also referred to as "other polymer") different from the addition polymer [P], a solvent, a crosslinking agent, an adhesion aid, and the like can be exemplified.

[0104] [Other polymer]

[0105] The other polymer is only required to be a polymer that does not have the structural unit [A] and the structural unit [B], and the kind of the main skeleton is not particularly limited. As the other polymer, for example, a polymer having a main skeleton of a polyamide acid, a polyamide acid ester, a polyimide, a polyorganosiloxane, a polyester, a polyalkylene amine, a polyurea, a polyamide, a polyamide-imide, an addition polymer, a polybenzoxazole, or the like can be exemplified.

[0106] From the viewpoint of obtaining a liquid crystal alignment film that is excellent in adhesiveness while achieving low-voltage driving, the other polymer is preferably at least one selected from the group consisting of a polyamide acid, a polyamide acid ester, a polyimide, and an addition polymer, and more preferably at least one selected from the group consisting of a polyamide acid, a polyamide acid ester, and a polyimide (hereinafter, also referred to as "polyimide-based polymer").

[0107] In the case where the liquid crystal alignment agent of the present disclosure contains a polyimide-based polymer having a photoalignment group as the other polymer, as the photoalignment group, for example, a photocrosslinking type, a photoisomerization type, a photodecomposition type, and the like can be exemplified. Among them, from the viewpoint of improvement in adhesiveness, the photoalignment group possessed by the polyimide-based polymer is preferably at least one selected from the group consisting of a photocrosslinking type and a photoisomerization type.

[0108] In the case where the liquid crystal aligning agent contains other polymer, the content of the other polymer is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and further preferably 5 parts by mass or more, relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent (i.e., the total amount of the addition polymer [P] and the other polymer). In addition, the content of the other polymer is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and further preferably 85 parts by mass or less, relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent, from the viewpoint of achieving stable low-voltage driving.

[0109] [Solvent]

[0110] The liquid crystal aligning agent of the present disclosure is preferably produced in the form of a liquid composition in which the addition polymer [P] and, as necessary, an arbitrary component are dissolved or dispersed in a solvent. The solvent is preferably an organic solvent, and examples thereof include aprotic polar solvents, phenol-based solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like.

[0111] Specific examples of the organic solvent used include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, isoamyl propionate, isoamyl isobutyrate, diisopinocampheyl ether, ethylene carbonate, propylene carbonate, cyclohexanone, diisobutyl ketone, 3-methoxy-1-butanol, and the like.

[0112] [Crosslinking agent]

[0113] The liquid crystal aligning agent of the present disclosure can contain a crosslinking agent. By further containing a crosslinking agent, a liquid crystal aligning film having more excellent adhesiveness while achieving low-voltage driving can be obtained. As the crosslinking agent, a compound having two or more groups selected from the group consisting of an oxiranyl group, an oxetanyl group, a cyclic sulfide group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, an isocyanate group, a protected isocyanate group, a polymerizable carbon-carbon unsaturated bond group (an alkenyl group, a vinyl ether group, a vinylphenyl group, a maleimide group, a (meth)acryloyl group, and the like), a β-alkoxyalkyl amide group, an oxazoline group, an aldehyde group, a carbodiimide group, a carboxyl group, a protected carboxyl group, a group "-CR60 =CR 61 -R 62 -”(wherein, R 60 is a monovalent organic group which is detached by reaction with an amino group; R 61 is a hydrogen atom or an alkyl group, R 62 is an electron-withdrawing group), silanol, and alkoxysilane.

[0114] From the viewpoint of obtaining a liquid crystal alignment film which exhibits good weak anchoring properties while having excellent close contact properties, the number of cross-linkable groups possessed by the cross-linking agent in one molecule is preferably from 2 to 10, more preferably from 2 to 6. In addition, the molecular weight of the cross-linking agent is preferably from 100 to 1,000, more preferably from 100 to 800, and further preferably from 100 to 700.

[0115] As specific examples of the cross-linking agent, as compounds having an oxiranyl group or an oxetanyl group, the following can be cited: ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, isocyanuric acid triglycidyl ester, glycerol polyglycidyl ether, pentaerythritol tetraglycidyl ether, 1,4-cyclohexane dimethanol diglycidyl ether, N,N,N',N'-tetraglycidyl glycoluril, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 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, an epoxidation reaction product based on hydrogen peroxide formation of 2,2'-diallyl bisphenol A diallyl ether, and the like.

[0116] As compounds having a cyclic carbonate group, the following compounds represented by the following formula (d1-1) and formula (d1-2), respectively, and the like can be cited.

[0117] As compounds having a hydroxyl group or a protected hydroxyl group, compounds having a hydroxymethyl group, a protected hydroxymethyl group, a hydroxyalkylamide group, or a protected hydroxyalkylamide group can be preferably used. As specific examples of these, for example, the following compounds represented by the following formula (d2-1) to formula (d2-5), the following formula (d3-1) to formula (d3-5), respectively, and the like can be cited.

[0118] As the compound having a carboxyl group or a protected carboxyl group, maleic acid, itaconic acid, trimellitic acid, tetracarboxylic acid, cis-1,2,3,4-tetrahydrophthalic acid, ethylene glycol bistrimellitate, propylene glycol bistrimellitate (Propylene Glycol Bistrimellitate), 4,4'-oxydiphthalic acid, and a protected body of these, and the like can be exemplified.

[0119] As the compound having a mercapto group or a protected mercapto group, 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-hydrothio butyryloxy)ethyl)-1,3,5-triazinane-2,4,6-trione, and the like can be exemplified.

[0120] As the compound having an amino group or a protected amino group, the compounds represented by the following formulae (d4-1) to (d4-5), and the like can be exemplified.

[0121] As the compound having a protected isocyanate group, the compounds in which the isocyanate group in toluene diisocyanate, xylene diisocyanate, chlorophenyl diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, or diphenylmethane diisocyanate is protected with 3,6-dimethylpyrazole, methyl ethyl ketone oxime, diethyl malonate, or ε-caprolactam, the compound represented by the following formula (d5-1), and the like can be exemplified.

[0122] As the compound having a polymerizable carbon-carbon unsaturated bond group, the compounds having a (meth)acryloyl group, a maleimide group, an alkenyl group, a vinylphenyl group, a vinyl ether group, or a 3-methylene tetrahydrofuran-2(3H)-one-5-yl group can be exemplified. As specific examples of these, ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, the compounds represented by the following formulae (d6-1) to (d6-8), and the like can be exemplified.

[0123] [Chemical 3]

[0124]

[0125] [Chemical 4]

[0126]

[0127] (In the formula (d2-4), Ac is an acetyl group)

[0128] [Chemical 5]

[0129]

[0130] [Chem. 6]

[0131]

[0132] [Chem. 7]

[0133]

[0134] [Chem. 8]

[0135]

[0136] As the cross-linking agent, from the viewpoint of obtaining a liquid crystal element that is more excellent in low-voltage driving of the liquid crystal element, a compound having no aromatic ring (hereinafter, also referred to as "aliphatic cross-linking agent") can be preferably used. The aliphatic cross-linking agent can be a compound including a chain structure, or can have a cyclic structure. As specific examples of the aliphatic cross-linking agent, compounds having no aromatic ring among the exemplified compounds can be listed.

[0137] From the viewpoint of achieving improvement in adhesiveness while realizing low-voltage driving, the content of the cross-linking agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and further preferably 2 parts by mass or more, relative to 100 parts by mass of the total amount of the polymer component contained in the liquid crystal alignment agent (i.e., the total amount of the addition polymer [P] and other polymers). In addition, from the viewpoint of obtaining good coatability, the content of the cross-linking agent is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 10 parts by mass or less, relative to 100 parts by mass of the total amount of the polymer component.

[0138] [Adhesion aid]

[0139] The adhesion aid is a component for improving the adhesiveness of the liquid crystal alignment film formed using the liquid crystal alignment agent to a substrate or a sealing agent. As the adhesion aid, a functional silane coupling agent having a reactive functional group can be preferably used. As the reactive functional group possessed by the functional silane coupling agent, a carboxyl group, a (meth)acryloyl group, an oxacyclopropyl group, an oxacyclobutyl group, a vinyl group, an isocyanate group, and the like can be listed.

[0140] As specific examples of the functional silane coupling agent, for example, trimethoxysilylbenzoic acid, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, 2-(3,4- epoxycyclohexyl)ethyltrimethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3- (meth)acryloyloxypropyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, 3- isocyanatopropyltriethoxysilane, and the like can be listed.

[0141] In the case where the liquid crystal alignment agent of the present disclosure contains a close contact aid, the content of the close contact aid is preferably 0.1 parts by mass to 20 parts by mass, more preferably 0.2 parts by mass to 10 parts by mass, with respect to 100 parts by mass of the total amount of the polymer component contained in the liquid crystal alignment agent.

[0142] As other components contained in the liquid crystal alignment agent, in addition to the above, for example, surfactants, antioxidants, metal chelate compounds, hardening accelerators, fillers, dispersants, photosensitizers, and the like can be exemplified. The blending ratio of the other components can be appropriately selected depending on each compound within a range not impairing the effects of the present disclosure.

[0143] The solid component concentration in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent of the liquid crystal alignment agent in the total mass of the liquid crystal alignment agent) can be appropriately selected in consideration of viscosity, volatility, and the like. The solid component concentration of the liquid crystal alignment agent is preferably in the range of 1% by mass to 10% by mass. If the solid component concentration is 1% by mass or more, the film thickness of the coating film can be sufficiently ensured, and a liquid crystal alignment film that exhibits more excellent liquid crystal alignment properties can be obtained, which is preferable in this respect. In addition, if the solid component concentration is 10% by mass or less, the coating film can be provided with a moderate thickness, and a liquid crystal alignment film that exhibits excellent liquid crystal alignment properties can be easily obtained. Furthermore, the viscosity of the liquid crystal alignment agent becomes moderate, and good coatability can be ensured.

[0144] Liquid crystal alignment film

[0145] The liquid crystal alignment film of the present disclosure is a weakly anchored liquid crystal alignment film formed from the liquid crystal alignment agent prepared as described above. Here, the so-called "weak anchoring" means that the orientation restricting force of the liquid crystal molecules is substantially zero in the in-plane direction, and even if the horizontal orientation of the liquid crystal molecules is forced, the orientation restricting force in the in-plane direction is substantially zero. Specifically, the so-called weak anchoring, for example, means that the azimuthal anchoring strength (A2) is less than 10 -4 J / m 2 , preferably the azimuthal anchoring strength (A2) is less than 10 -5 J / m 2 In the state of weak anchoring (also referred to as zero surface anchoring), by control based on an external field such as an electric field, a magnetic field, or the like, the in-plane orientation direction can be freely rotated by 360°. On the other hand, a strongly anchored liquid crystal alignment film has stronger anchoring energy than a weakly anchored liquid crystal alignment film, and specifically, preferably the azimuthal anchoring strength (A2) is greater than 10 -4 J / m 2 In addition, in the present specification, the azimuthal anchoring strength of the liquid crystal alignment film is a value calculated from the electric field response threshold.

[0146] The method for producing a weakly anchored liquid crystal alignment film using the liquid crystal alignment agent of the present disclosure is not particularly limited, and can be performed using the same method as in the case of producing a liquid crystal alignment film using a conventionally known liquid crystal alignment agent. In terms of being able to simply perform weakly anchored liquid crystal alignment film formation, a method in which the liquid crystal alignment agent of the present disclosure is applied to a substrate, preferably the application surface is heated, is preferred.

[0147] The substrate on which the weakly anchored liquid crystal alignment film is formed is not particularly limited. As the substrate, for example, a transparent substrate containing a glass such as float glass, soda glass, or the like; a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly(alicyclic olefin), or the like can be used.

[0148] The method for applying the liquid crystal alignment agent to the substrate is not particularly limited. The application of the liquid crystal alignment agent can be performed, for example, by a spin coating method, a printing method (for example, an offset printing method, a flexographic printing method, or the like), an inkjet method, a slit coating method, a bar coater method, an extrusion die method, a direct gravure coater method, a chamber doctor coater method, an offset gravure coater method, a dip coater method, an MB coater method, or the like. Among them, the application of the liquid crystal alignment agent is preferably performed by an inkjet method.

[0149] After the application of the liquid crystal alignment agent, preheating (pre-baking) is preferably performed for the purpose of preventing sagging of the liquid crystal alignment agent 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 performed 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 film formed is preferably 0.001 μm to 2.5 μm. By the described operation, a weakly anchored liquid crystal alignment film can be simply manufactured. Furthermore, the coated film after post-baking can be subjected to an alignment treatment (for example, a rubbing alignment treatment or a photo-alignment treatment) as necessary, whereby a weakly anchored liquid crystal alignment film is obtained.

[0150] Liquid crystal element and method for manufacturing the same

[0151] The liquid crystal element of the present disclosure includes a weakly-anchoring liquid crystal alignment film formed using the liquid crystal alignment agent described above. The driving mode of the liquid crystal in the liquid crystal element is not particularly limited, and various modes such as a Twisted Nematic (TN) mode, a Super Twisted Nematic (STN) mode, a Vertical Alignment (VA) mode (including a Vertical Alignment-Multi-domain Vertical Alignment (VA-MVA) mode, a Vertical Alignment-Patterned Vertical Alignment (VA-PVA) mode, and the like), an IPS mode, an FFS mode, an Optically Compensated Bend (OCB) mode, a Polymer Sustained Alignment (PSA) mode, an Electrically Controlled Birefringence (ECB) mode, and the like can be applied. Among these, the liquid crystal element of the IPS mode or the FFS mode or the like can be preferably applied.

[0152] The liquid crystal element of the present disclosure can be manufactured, for example, by a method including Process A and Process B described below. Furthermore, the order of Process A and Process B is not particularly limited, and Process B can be performed after Process A, or Process A can be performed after Process B. Alternatively, Process A and Process B can be performed simultaneously.

[0153] Process A: a process of forming a weakly-anchoring liquid crystal alignment film on one of a pair of substrates using a liquid crystal alignment agent for weakly-anchoring film formation

[0154] Process B: a process of forming a strongly-anchoring liquid crystal alignment film on the other of the pair of substrates (i.e., a substrate on which a weakly-anchoring liquid crystal alignment film is not formed)

[0155] Process A is preferably performed based on Process 1 shown below, and Process B is preferably performed based on Process 1 and Process 2 shown below. Furthermore, a liquid crystal cell is constructed by Process 3 using the substrate on which a liquid crystal alignment film is formed obtained by Process A and Process B, and thus a liquid crystal element can be obtained. In Process 1, the substrate used differs depending on the desired operation mode. In Process 2 and Process 3, each operation mode is common.

[0156] Process 1: Formation of a Film

[0157] First, a coating film is formed on each of the substrates in a pair of substrates by applying a liquid crystal alignment agent on the surface of each of the substrates, and preferably, the coated surface is heated. As the liquid crystal alignment agent for forming a strong anchoring liquid crystal alignment film, a conventionally known liquid crystal alignment agent can be appropriately used.

[0158] As to a pair of substrates, for example, in the case of manufacturing a liquid crystal element of an IPS type or an FFS type, a substrate provided with an electrode patterned in a comb shape (hereinafter, also referred to as "first substrate") and an opposing substrate not provided with an electrode (hereinafter, also referred to as "second substrate") are used. As the electrode, a transparent conductive film can be cited. As the transparent conductive film, a NESA (NESA is a registered trademark of PPG Industries, Inc.) film containing tin oxide (Sn02), an Indium Tin Oxide (ITO) film containing indium oxide-tin oxide (In203-Sn02), or the like can be used. As the mode when forming a liquid crystal alignment film on the first substrate and the second substrate, a mode in which 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 (first mode) and a mode in which a weak anchoring liquid crystal alignment film is formed on the first substrate and a strong anchoring liquid crystal alignment film is formed on the second substrate (second mode) can be cited. Among these, from the viewpoint of low voltage driving of the liquid crystal element, the first mode is preferable.

[0159] <Process 2: Alignment Treatment>

[0160] In the case of manufacturing a liquid crystal element of an IPS type or an FFS type, at least one of the coating films formed on the first substrate and the second substrate in the process 1 is subjected to a treatment for imparting a liquid crystal alignment ability (alignment treatment). As the alignment treatment, a rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton or nylon or the like, or a photo-alignment treatment in which the coating film is subjected to light irradiation to impart a 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 on only 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 that exhibits a good liquid crystal alignment property, it is preferable that a liquid crystal alignment agent for forming a strong anchoring liquid crystal alignment film be applied on one of the first substrate and the second substrate, and the alignment treatment be performed only on the coating film formed thereby. In that case, the strong anchoring liquid crystal alignment film can be a rubbing alignment film formed by a rubbing alignment treatment, or can be a photo-alignment film formed by a photo-alignment treatment. From the aspect that the liquid crystal alignment property and the close contact property can be more excellent, the liquid crystal alignment agent used in the formation of the strong anchoring liquid crystal alignment film is preferably a liquid crystal alignment agent containing a crosslinking agent, and from the aspect that the improvement effect on the low voltage driving of the liquid crystal element is high, it is more preferable that the crosslinking agent not have an aromatic ring.

[0161] Further, according to the weakly-anchoring liquid crystal alignment film formed by the liquid crystal alignment agent of the present disclosure, even if no alignment treatment such as rubbing alignment treatment or photo-alignment treatment is performed, a liquid crystal element that exhibits good liquid crystal alignment properties can be obtained. By utilizing this characteristic, the weakly-anchoring liquid crystal alignment film formed by the liquid crystal alignment agent of the present disclosure can be disposed as a protective film provided on a color filter in a liquid crystal element, and the weakly-anchoring liquid crystal alignment film can be provided with a function as a protective film (specifically, planarization or protection from impurities or humidity, etc.).

[0162] <Process 3: Construction of a Liquid Crystal Cell>

[0163] A liquid crystal cell in which a liquid crystal layer is disposed between two substrates disposed facing each other is manufactured using a substrate on which a strongly-anchoring liquid crystal alignment film is formed and a substrate on which a weakly-anchoring liquid crystal alignment film is formed. In manufacturing the liquid crystal cell, for example, a method in which two substrates are disposed facing each other with a gap therebetween, the peripheral portions of the two substrates are bonded using a sealant, a filler liquid crystal is injected into the cell gap surrounded by the substrate surfaces and the sealant, and the injection hole is sealed; or a method using a liquid crystal drop fill (ODF) method can be exemplified. As the sealant, for example, an epoxy resin containing a hardening agent and alumina balls as spacers, etc. can be used. As the liquid crystal constituting the liquid crystal layer, a nematic liquid crystal, a smectic liquid crystal, etc. can be exemplified, of which a nematic liquid crystal is preferred.

[0164] In the case of manufacturing a liquid crystal display device, then, a polarizing plate is bonded to the outer surface of the liquid crystal cell. As the polarizing plate, a polarizing plate in which a polarizing film called an "H film" in which polyvinyl alcohol is extended and oriented while being made to absorb iodine is sandwiched by a cellulose acetate protective film or a polarizing plate containing the H film itself can be exemplified.

[0165] 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 watch, 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 smartphone, various monitors, a liquid crystal television, an information display, etc., or a light control device, a phase difference film, etc.

[0166] According to the present disclosure, the following means can be provided.

[0167] [Means 1] A liquid crystal alignment agent containing an addition polymer [P] comprising: a structural unit [A] having a hydroxyl group bonded to a carbon atom in a chain structure or within an aliphatic ring (wherein a carbon atom in a carbonyl group and a carbon atom constituting a main chain of a polymer are excluded); and a structural unit [B] having a partial structure represented by the formula (1) and being different from the structural unit [A].

[0168] [Means 2] The liquid crystal alignment agent according to [Means 1], wherein the structural unit [A] has a structural unit represented by the formula (2).

[0169] [Means 3] The liquid crystal alignment agent according to [Means 2], wherein A in the formula (2) is 1 does not have an aromatic ring.

[0170] [Means 4] The liquid crystal alignment agent according to [Means 2] or [Means 3], wherein A in the formula (2) is 1 a substituted or unsubstituted divalent chain hydrocarbon group, or a divalent group containing -O- or -CO- between carbon-carbon bonds in a substituted or unsubstituted divalent chain hydrocarbon group.

[0171] [Means 5] The liquid crystal alignment agent according to any one of [Means 2] to [Means 4], wherein B in the formula (2) is 1 and B 2 are each independently a hydrogen atom, a monovalent hydrocarbon group, a monovalent halogenated hydrocarbon group, or a monovalent group containing -O- between carbon-carbon bonds in a monovalent hydrocarbon group or a monovalent halogenated hydrocarbon group.

[0172] [Means 6] The liquid crystal alignment agent according to any one of [Means 1] to [Means 5], wherein the addition polymer [P] further comprises a structural unit [C] having a partial structure represented by the formula (3) and being different from the structural unit [A] and the structural unit [B].

[0173] [Means 7] The liquid crystal alignment agent according to any one of [Means 1] to [Means 6], further containing at least one selected from the group consisting of a polyamic acid, a polyamic acid ester, and a polyimide.

[0174] [Means 8] The liquid crystal alignment agent according to any one of [Means 1] to [Means 7], further containing a crosslinking agent.

[0175] [Means 9] The liquid crystal alignment agent according to [Means 8], wherein the crosslinking agent does not have an aromatic ring.

[0176] [Means 10] The liquid crystal alignment agent according to any one of [Means 1] to [Means 9] for forming a weakly-anchored liquid crystal alignment film.

[0177] [Means 11] A liquid crystal alignment film is formed using the liquid crystal alignment agent according to any one of [Means 1] to [Means 10].

[0178] [Means 12] A liquid crystal element including the liquid crystal alignment film according to [Means 11].

[0179] [Means 13] A method for manufacturing a liquid crystal element including a pair of substrates including a first substrate and a second substrate, and a liquid crystal layer disposed between the pair of substrates, the method including a step of forming a liquid crystal alignment film on a surface of one of the pair of substrates by applying a liquid crystal alignment agent according to any one of [Means 1] to [Means 10].

[0180] [Means 14] The method for manufacturing a liquid crystal element according to [Means 13], wherein the liquid crystal alignment film formed from the liquid crystal alignment agent according to any one of [Means 1] to [Means 10] is a weakly-anchoring liquid crystal alignment film, and the method further includes a step of forming a strongly-anchoring liquid crystal alignment film having a stronger anchoring energy than the weakly-anchoring liquid crystal alignment film on a surface of one of the first substrate and the second substrate other than the substrate on which the weakly-anchoring liquid crystal alignment film is formed.

[0181] [Means 15] The method for manufacturing a liquid crystal element according to [Means 14], wherein the strongly-anchoring liquid crystal alignment film is a rubbing alignment film or a photoalignment film.

[0182] [Means 16] The method for manufacturing a liquid crystal element according to [Means 14] or [Means 15], wherein the first substrate has a pair of electrodes, and the second substrate does not have an electrode, the strongly-anchoring liquid crystal alignment film is formed on a surface of the first substrate, and the weakly-anchoring liquid crystal alignment film is formed on a surface of the second substrate.

[0183] [Examples]

[0184] Hereinafter, the present application will be specifically described by examples, but the present application is not limited to the following examples. In addition, in the examples and comparative examples, "parts" and "%" are on a mass basis, unless otherwise specified.

[0185] In the following examples, the imidization rate of the polyimide, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer were measured by the following methods.

[0186] <Imidization rate of polyimide>

[0187] The solution of the polyimide was poured into pure water, and the obtained precipitate was sufficiently dried under reduced pressure at room temperature, and then dissolved in deuterated dimethyl sulfoxide, and1H-NMR spectrum was measured at room temperature with tetramethylsilane as a reference material. 1 H-Nuclear Magnetic Resonance, 1 H-NMR) measurement. From the obtained 1 H-NMR spectrum, the imidization rate [%] was calculated using the following equation (1).

[0188] Imidization rate [%] = (1 - (β 1 / (β 2 x α)) x 100 (1)

[0189] (In equation (1), β 1 is the peak area of the proton source of the NH group appearing around the chemical shift 10 ppm, β 2 is the peak area of the other proton source, and α is the number ratio of the other proton to 1 proton of the NH group in the precursor (polyamic acid) of the polymer)

[0190] <Weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer>

[0191] The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) under the following conditions. The molecular weight distribution (Mw / Mn) was calculated from the obtained Mw and Mn.

[0192] Apparatus: "GPC-101" by Showa Denko K.K.

[0193] GPC column: combination of "GPC-KF-801", "GPC-KF-802", "GPC-KF-803", and "GPC-KF-804" manufactured by Shimadzu GLC, Inc.

[0194] Mobile phase: tetrahydrofuran (THF)

[0195] Column temperature: 40°C

[0196] Flow rate: 1.0 mL / min

[0197] Sample concentration: 1.0 mass%

[0198] Sample injection amount: 100 μL

[0199] Detector: differential refractometer

[0200] Standard material: monodisperse polystyrene

[0201] The abbreviations of the compounds are described below. In addition, hereinafter, the compound represented by Formula (X) is sometimes simply denoted as "Compound (X)".

[0202] <Monomer having unsaturated bond>

[0203] [Chemical Formula 9]

[0204]

[0205] [Chemical Formula 10]

[0206]

[0207] [Chemical Formula 11]

[0208]

[0209] [Chemical Formula 12]

[0210]

[0211] <Four carboxylic acid dianhydride>

[0212] [Chemical Formula 13]

[0213]

[0214] <Diamine>

[0215] [Chemical Formula 14]

[0216]

[0217] <Additive>

[0218] [Chemical Formula 15]

[0219]

[0220] <Synthesis of polymer>

[0221] 1. Synthesis of addition polymer

[0222] [Synthesis Example 1]

[0223] In a 100 mL two-necked flask, 45 parts by mole of compound (MA-1), 25 parts by mole of compound (MA-7), 25 parts by mole of compound (MB-2), and 5 parts by mole of compound (M-1) relative to 100 parts by mole of the total of the polymerizable monomers, 2 parts by mole of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, and N-methyl-2-pyrrolidone (NMP) as a solvent were added under nitrogen, and polymerization was performed at 70°C for 6 hours. After reprecipitation was performed in methanol, the precipitate was filtered and vacuum-dried at room temperature for 8 hours, whereby the target addition polymer (which will be referred to as polymer (PM-1)) was obtained.

[0224] [Synthesis Examples 2 to 10]

[0225] The same operation as in Synthesis Example 1 was performed except that the kinds and amounts of the polymerizable monomers used in the reaction were changed as described in Table 1, and addition polymers (which will be referred to as polymers (PM-2) to (PM-10)) were obtained.

[0226] In Table 1, the numerical values of the monomers indicate the proportions (molar ratios) of each compound relative to 100 parts by mole of the total amount of the monomers used in the synthesis. The "branched alkyl monomer" corresponds to a monomer that provides structural unit [B], the "aliphatic OH monomer" corresponds to a monomer that provides structural unit [A], the "linear alkyl monomer" corresponds to a monomer that provides structural unit (C), and the "other monomer" corresponds to a monomer that provides another structural unit.

[0227] [Table 1]

[0228]

[0229] 2. Synthesis of Polyamide Acid

[0230] [Synthesis Example 11]

[0231] Compound (T-3) as a tetracarboxylic dianhydride and compound (D-1) as a diamine compound were dissolved in NMP, and a reaction was performed at 60°C for 6 hours, whereby a solution containing 20 mass% of polyamide acid (which will be referred to as polymer (PI-1)) was obtained.

[0232] [Synthesis Examples 12 to 17, Synthesis Example 19, and Synthesis Example 20]

[0233] The same operation as in Synthesis Example 11 was performed except that the kinds and amounts of the tetracarboxylic dianhydride and diamine compound used were changed as described in Table 2, to obtain polyamic acid (these were made into Polymer (PI-2) to Polymer (PI-7), Polymer (PI-9), and Polymer (PI-10)).

[0234] 3. Synthesis of polyimide

[0235] [Synthesis Example 18]

[0236] Compound (T-5) as the tetracarboxylic dianhydride and compound (D-14) as the diamine compound were dissolved in NMP, and a reaction was performed at 60°C for 6 hours, to obtain a solution containing 20 mass% of polyamic acid. Subsequently, NMP was added to the obtained polyamic acid solution to make a solution having a polyamic acid concentration of 10 mass%, and pyridine and acetic anhydride were added, and a dehydration ring closure reaction was performed at 80°C for 4 hours. After the dehydration ring closure reaction, solvent replacement was performed on the solvent in the system using fresh NMP, to thereby obtain a solution containing 15 mass% of polyimide (this was made into Polymer (PI-8)) having an imidization rate of about 30%.

[0237] In Table 2, the values of the tetracarboxylic dianhydride (dianhydride 1 to dianhydride 3) represent the proportion (molar ratio) of each compound with respect to the total amount of 100 mol of the tetracarboxylic dianhydride used in the synthesis of the polymer. The values of the diamine compound (diamine 1 to diamine 4) represent the proportion (molar ratio) of each compound with respect to the total amount of 100 mol of the diamine compound used in the synthesis of the polymer.

[0238] [Table 2]

[0239]

[0240] Preparation of liquid crystal alignment agent and evaluation of inkjet coatability

[0241] 1. Preparation of liquid crystal alignment agent for weakly-anchoring film formation

[0242] [Example 1]

[0243] To the solution containing 10 parts by mass of the polymer (PM-1) obtained in Synthesis Example 1 and the solution containing 90 parts by mass of the polymer (PI-5) obtained in Synthesis Example 15, dilution was performed using N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), butyl cellosolve (BC), diacetone alcohol (DAA), and diethylene glycol diethylether (DGDE), to prepare a solution having a solvent composition ratio of NMP:GBL:BC:DAA:DGDE = 30:30:15:15:10 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered using a filter having a pore size of 0.2 μm, to thereby prepare a liquid crystal alignment agent for a weakly-anchoring film formation (AL-1).

[0244] 2. Evaluation of inkjet coatability

[0245] As a substrate to which a liquid crystal alignment agent was to be applied, a glass substrate having a transparent electrode including an ITO film was heated on a hot plate at 200°C for 1 minute, and then, subjected to ultraviolet / ozone cleaning, so that the contact angle of water on the surface of the transparent electrode became 10° or less. Immediately after the substrate, the liquid crystal alignment agent for a weakly-anchoring film formation (AL-1) was applied to the surface of the transparent electrode of the glass substrate having the transparent electrode using an inkjet coater (manufactured by Shibaura Mechatronics). At this time, the application conditions were set to be two round trips (a total of four times) of application at 2,500 times / (nozzle / minute) and 250 mg / 10 seconds of discharge amount. After the application, the substrate was left to stand for 1 minute, and then, heated at 50°C, to thereby form a coating film having an average film thickness of 0.1 μm. The obtained coating film was visually observed under irradiation of an interference fringe measuring lamp (a sodium lamp), and evaluated for unevenness and depression.

[0246] In addition, the same operation as described above was performed except that the heating temperature at the time of coating film formation was changed to 60°C and 80°C, and the presence or absence of unevenness and depression in the coating film was observed. The case where neither unevenness nor depression was found at any one of the heating temperatures of 50°C, 60°C, and 80°C was rated as "particularly good ( ) " in terms of inkjet coatability, the case where at least one of unevenness and depression was found at one of the heating temperatures of 50°C, 60°C, and 80°C was rated as "good (0)", the case where at least one of unevenness and depression was found at two of the heating temperatures was rated as "fair (Δ)", and the case where at least one of unevenness and depression was found at all of the heating temperatures was rated as "poor (X)". As a result, the evaluation in the example was "good (0)".

[0247] [Examples 2 to 9, Comparative Examples 1 to 3]

[0248] Weakly-anchoring film-forming liquid crystal aligning agent (AL-2) to weakly-anchoring film-forming liquid crystal aligning agent (AL-12) were prepared in the same solvent composition and solid content concentration as in Example 1 except for changing the kind and amount of the polymer and the additive as shown in Table 3, and evaluation of inkjet coatability was performed. The evaluation results are shown in Table 3.

[0249] 3. Preparation of strongly-anchoring film-forming liquid crystal aligning agent

[0250] [Preparation Examples 1 to 3]

[0251] Strongly-anchoring film-forming liquid crystal aligning agent (AL-13) to strongly-anchoring film-forming liquid crystal aligning agent (AL-15) were prepared in the same solvent composition and solid content concentration as in Example 1 except for changing the kind and amount of the polymer and the additive as shown in Table 3. For strongly-anchoring film-forming liquid crystal aligning agent (AL-13) to strongly-anchoring film-forming liquid crystal aligning agent (AL-15), too, evaluation of inkjet coatability was performed, and it was confirmed that the coatability was not problematic. The evaluation results are shown in Table 3.

[0252] [Table 3]

[0253]

[0254] As shown in Table 3, in Examples 1 to 9 in which the liquid crystal aligning agent contains the addition polymer [P] containing structural unit [A] and structural unit [B], the inkjet coatability was evaluated as good (O). In contrast, in Comparative Example 1 in which an addition polymer not containing structural unit [A] was used instead of addition polymer [P], in Comparative Example 2 in which an addition polymer not containing structural unit [B] was used, and in Comparative Example 3 in which an addition polymer not containing structural unit [A] and structural unit [B] was used, the inkjet coatability was evaluated as poor (X).

[0255] It is presumed that in Comparative Example 1 in which an addition polymer not containing structural unit [A] and structural unit [B] of the two was used instead of addition polymer [P], and in Comparative Example 3 in which an addition polymer containing structural unit [C] instead of structural unit [A] and structural unit [B] was used, the hydrophobicity of the liquid crystal aligning agent became high, and thus the coatability at the time of inkjet coating became poor (the edge straightness became poor), and as a result, unevenness of the coating film occurred. In addition, it is presumed that in Comparative Example 2 in which an addition polymer not containing structural unit [B] of the two was used instead of addition polymer [P], the water absorption or the surface activity of the liquid crystal aligning agent became high, and thus the coatability at the time of inkjet coating became excessively high (the edge straightness became poor).

[0256] Manufacture of liquid crystal element, and evaluation of close contact property and low voltage driving (FFS type liquid crystal display element)

[0257] Various properties were evaluated by manufacturing FFS type liquid crystal cells. In manufacturing the FFS type liquid crystal cells, first, a substrate (electrode substrate) having an electrode pair of a bottom electrode not having a pattern, an insulating layer formed of a silicon nitride film, and a top electrode patterned into a comb shape on one surface of a glass substrate, and a counter substrate (counter substrate) not provided with an electrode were prepared.

[0258] A plan view of the top electrode used is shown in Figure 2 (a) and (b) of FIG. 1. Further, Figure 2 (a) of FIG. 1 is a plan view of the top electrode, Figure 2 (b) of FIG. 1 is Figure 2 (a) of FIG. 1. In the present embodiment, the line width dl of the electrode was set to 4 μm, and the distance d2 between the electrodes was set to 6 μm. In addition, as the top electrode, driving electrodes of four systems of Electrode A, Electrode B, Electrode C, and Electrode D were used. Figure 3 Further, the bottom electrode functions as a common electrode acting on all of the driving electrodes of the four systems, and the regions of the driving electrodes of the four systems become pixel regions, respectively.

[0259] [Example 10: Photo-alignment FFS type liquid crystal display element]

[0260] 1. Manufacture of liquid crystal display element

[0261] (1) Formation of weakly-anchoring liquid crystal alignment film

[0262] The weakly-anchoring film-forming liquid crystal alignment agent (AL-1) was applied to one of the substrate surfaces of the counter substrate using a spin coater, and after heating on a hot plate at 80°C for 1 minute, heating was performed in a 230°C oven in which the interior of the oven had been replaced with nitrogen for 30 minutes, to form a weakly-anchoring liquid crystal alignment film having an average film thickness of 100 nm.

[0263] (2) Formation of strongly-anchoring liquid crystal alignment film based on photo-alignment method

[0264] The strongly-anchoring film-forming liquid crystal alignment agent (AL-13) was applied to the electrode formation surface of the electrode substrate using a spin coater, and after heating on a hot plate at 80°C for 1 minute, heating was performed in a 230°C oven in which the interior of the oven had been replaced with nitrogen for 30 minutes, to form a coating film having an average film thickness of 100 nm. With respect to the surface of the coating film, ultraviolet rays including a bright line of 254 nm polarized by a straight line were irradiated from the normal direction of the substrate at 200 mJ / cm 2And the light orientation treatment is performed. At this time, the direction of the line segment on which the polarizing plane of the polarized ultraviolet light is projected on the substrate is set in parallel with the direction of the bidirectional arrow in (b) of Figure 2 The polarizing plane direction is set in parallel with the direction of the bidirectional arrow in (b) of

[0265] (3) Manufacture of the light orientation FFS type liquid crystal display element

[0266] The outer periphery of the face of one of the substrates manufactured in (1) and (2) having the liquid crystal orientation film is left as a liquid crystal injection port, and an epoxy resin adhesive agent in which alumina balls of 3.5 μm in diameter are put is applied using a dispenser. After that, the faces of the pair of substrates having the liquid crystal orientation film are made to face each other and are press-bonded, and the adhesive agent is heat-hardened at 150°C for 1 hour. Subsequently, after a negative type nematic liquid crystal (manufactured by Merck, MLC-6608, Δn = 0.083) is filled into the gap between the substrates from the liquid crystal injection port, the liquid crystal injection port is sealed using an epoxy-based adhesive agent. Further, in order to remove the flow orientation at the time of liquid crystal injection, heating at 120°C is performed and then slow cooling to room temperature is performed.

[0267] 2. Evaluation

[0268] (1) Evaluation of adhesiveness

[0269] A weak anchor film forming liquid crystal orientation agent (AL-1) and a strong anchor film forming liquid crystal orientation agent (AL-13) were applied to glass substrates using a spin coater, and after heating on a hot plate at 80°C for 1 minute, heat treatment was performed in a 230°C oven in which the interior of the oven was replaced with nitrogen for 30 minutes, thereby manufacturing two glass substrates on which a coating film having an average film thickness of 100 nm was formed. Next, a liquid crystal sealing agent (manufactured by Shimizu Chemical, S-WB21) was applied to the center portion of the face of one of the glass substrates having the coating film, and the other glass substrate was attached so that the coating film of the other glass substrate was in contact with the liquid crystal sealing agent. The amount of application of the liquid crystal sealing agent was set so that the diameter of the liquid crystal sealing agent after the substrates were attached was 4 mm. After that, light of 30,000 J / m 2 (30,000 J / m 2 ) was irradiated using a metal halide lamp, and heating was performed in an oven at 120°C for 1 hour, thereby obtaining an evaluation cell. After that, the evaluation cell was press-bonded using a small table-top tester (model: EZ-LX) manufactured by Shimadzu Seisakusho, and the pressure (N) at which peeling of the film (mainly peeling caused by destruction of the interface between the liquid crystal sealing agent and the film or destruction of aggregation in the liquid crystal sealing agent) occurred was measured. The adhesiveness of the film to the liquid crystal sealing agent and the substrate (N / mm 2 ) was calculated by dividing the pressure (N) at which peeling occurred by the area of the liquid crystal sealing agent (mm 2 ).). As for the evaluation, the measured value of the pressure was 1.5 N / mm 2 the above and not more than 1.5 N / mm 2 the above and not more than 1.0 N / mm 2 the above and not more than 1.0 N / mm 2 the above and not more than 1.0 N / mm

[0270] (2) Evaluation of Low Voltage Drive

[0271] The liquid crystal display element produced in the above 1. (3) was sandwiched with two polarizing plates in such a manner that the luminance became the minimum, and the liquid crystal display element was set between a backlight and a luminance meter set in such a manner that the optical axes were coincident. Thereafter, a voltage was applied to the liquid crystal display element at intervals of 0.1 V until 10 V. By measuring the luminance with respect to the applied voltage, a V-T curve was obtained, and the value of the voltage at which the luminance became the maximum was estimated. As for the evaluation, as for the facing substrate as well as the electrode substrate, a liquid crystal display element in which a liquid crystal alignment film was formed using a strong anchor film-forming liquid crystal alignment agent (AL-13) and by a photo-alignment method was prepared as a reference cell, and it was judged in what degree the maximum luminance voltage of the liquid crystal display element produced in each example was low with respect to the maximum luminance voltage of the reference cell. The case where the maximum luminance voltage of the liquid crystal display element produced in the above 1. (3) was low by more than 0.6 V with respect to the maximum luminance voltage of the reference cell was set as "particularly good (O)", the case where the maximum luminance voltage was low by more than 0.2 V and 0.6 V or less with respect to the maximum luminance voltage of the reference cell was set as "good (O)", the case where the maximum luminance voltage was low by more than 0 V and 0.2 V or less with respect to the maximum luminance voltage of the reference cell was set as "fair (Δ)", and the case where the maximum luminance voltage of the liquid crystal display element was 0 V or less with respect to the maximum luminance voltage of the reference cell was set as "poor (X)". As a result, the evaluation was "particularly good (O)" in the present example.

[0272] [Examples 11 to 18, Comparative Examples 4 to 6, and Comparative Example 10]

[0273] A liquid crystal alignment film was formed in the same manner as in Example 10 except that the liquid crystal alignment agent used was changed as shown in Table 4, and a photo-alignment FFS-type liquid crystal display element was produced, and the adhesiveness and the evaluation of low voltage drive were performed. Further, the reference cell in the evaluation of low voltage drive of Example 18 was produced using a strong anchor film-forming liquid crystal alignment agent (AL-15). The evaluation results are shown in Table 4.

[0274] [Example 19: Rubbing alignment FFS-type liquid crystal display element]

[0275] 1. Manufacture of liquid crystal display element

[0276] Manufacture Figure 1 The FFS-type liquid crystal display element 10 shown in FIG. 1 was manufactured and various characteristics were evaluated.

[0277] (1) Formation of weakly-anchoring liquid crystal alignment film

[0278] A weakly-anchoring liquid crystal alignment film was formed using the liquid crystal alignment agent for weakly-anchoring film formation (AL-1) in the same manner as in Example 10.

[0279] (2) Formation of strongly-anchoring liquid crystal alignment film based on rubbing alignment method

[0280] The liquid crystal alignment agent for strongly-anchoring film formation (AL-14) was applied to the electrode formation surface of the electrode substrate using a spin coater, and after heating on a hot plate at 80°C for 1 minute, heating was performed in a nitrogen-substituted oven at 230°C for 30 minutes, to form a coating film having an average film thickness of 100 nm. With respect to the surface of the coating film, rubbing treatment was performed twice using a rubbing machine having a roller wound with a cloth made of artificial silk, at a roller rotation speed of 1,000 rpm, a stage moving speed of 30 mm / sec, and a bristle press-in length of 0.3 mm. At this time, the rubbing direction was set in parallel with the direction of the bidirectional arrow in (b) of FIG. 1. After the coating film subjected to the rubbing alignment treatment was ultrasonically cleaned in ultrapure water for 1 minute, drying was performed in an oven at 100°C for 10 minutes, to form a strongly-anchoring liquid crystal alignment film. Figure 2

[0281] (3) Manufacture of FFS-type liquid crystal display element

[0282] The FFS-type liquid crystal display element was manufactured in the same manner as in Example 10, using the pair of substrates manufactured in the above (1) and (2).

[0283] 2. Evaluation

[0284] In addition to using the liquid crystal display element manufactured in the above 1.(3), evaluation of adhesiveness and low-voltage driving was performed in the same manner as in Example 10. Furthermore, the reference cell in the evaluation of low-voltage driving was manufactured using the liquid crystal alignment agent for strongly-anchoring film formation (AL-14). The evaluation results are shown in Table 4.

[0285] [Examples 20 to 27, Comparative Examples 7 to 9, and Comparative Example 11]

[0286] In addition to changing the liquid crystal alignment agent used as shown in Table 4, a rubbing alignment FFS-type liquid crystal display element was manufactured in the same manner as in Example 19, and evaluation of adhesiveness and low-voltage driving was performed. The evaluation results are shown in Table 4. ​

[0287] [Table 4]

[0288]

[0289] As shown in Table 4, in Examples 10 to 27 in which the weakly anchoring film-forming liquid crystal aligning agent (AL-1) to (AL-9) of Examples 1 to 9 having excellent inkjet coatability were used, the adhesiveness and the low voltage driving were evaluated as particularly good ( ) or good (O), and a balance of various characteristics was achieved. In particular, in Examples 11 to 14 and 20 to 23 in which the weakly anchoring film-forming liquid crystal aligning agent (AL-2) to (AL-5) containing the structural unit [C] in addition to the structural unit [A] and the structural unit [B] in the addition polymer [P] were used, the adhesiveness was found to be further improved compared to the other examples, and was evaluated as particularly good ( ). It can be said that, when the adhesiveness and the inkjet coatability are both taken into consideration while achieving the low voltage driving, it is preferable that the liquid crystal aligning agent contain the addition polymer [P].

[0290] On the other hand, in Comparative Examples 4 to 9 in which the weakly anchoring film-forming liquid crystal aligning agent (AL-10) to (AL-12) of Comparative Examples 1 to 3 having poor inkjet coatability were used, at least one of the adhesiveness and the low voltage driving was evaluated to be worse than in the examples. In detail, in Comparative Examples 4 and 7 in which an addition polymer not containing the structural unit [A] was used instead of the addition polymer [P], and Comparative Examples 6 and 9 in which an addition polymer not containing the structural unit [A] and the structural unit [B] was used, the adhesiveness was evaluated as poor (X). In addition, in Comparative Examples 5 and 8 in which an addition polymer not containing the structural unit [B] was used instead of the addition polymer [P], the low voltage driving was evaluated as possible ( ), and the results were worse than in Examples 10 to 27. In addition, in Comparative Examples 10 and 11 in which only a strongly anchoring film-forming liquid crystal aligning agent was used, the adhesiveness was evaluated as particularly good ( ), but the low voltage driving was evaluated as poor (X), and the usefulness of the liquid crystal aligning agent of the present disclosure was shown.

[0291] As a result of the above, it was clarified that, according to the liquid crystal aligning agent of the present disclosure, the low voltage driving of the liquid crystal element can be achieved, and a liquid crystal aligning film having excellent adhesiveness and excellent coatability can be formed.

Claims

1. A liquid crystal alignment agent comprising an addition polymer [P], said addition polymer [P] comprising: a structural unit [A] having a hydroxyl group bonded to a carbon atom in a chain structure or an aliphatic ring, wherein the carbon atom does not include the carbon atom in a carbonyl group and the carbon atom constituting the main chain of the polymer; and a structural unit [B] having a partial structure represented by the following formula (1) and different from said structural unit [A]; * 1 -CO-OR 1 …(1) In equation (1), R 1 It is a monovalent chain hydrocarbon group with a branched structure; 1 "" indicates a bond with the carbon atoms that make up the main chain of the polymer.

2. The liquid crystal alignment agent according to claim 1, wherein, The structural unit [A] has the structural unit represented by the following formula (2); * 2 -CO-OA 1 -C(B 1 )(B 2 )-OH…(2) In equation (2), A 1 It is a single bond or a divalent organic group; B 1 and B 2 Each of these can be independently a hydrogen atom, a halogen atom, or a monovalent organic group; 2 "" indicates a bond with the carbon atoms that make up the main chain of the polymer.

3. The liquid crystal alignment agent according to claim 2, wherein, In the formula (2) A 1 It does not have an aromatic ring.

4. The liquid crystal alignment agent according to claim 2, wherein, In the formula (2) A 1 It is a substituted or unsubstituted divalent chain hydrocarbon group, or a divalent group containing -O- or -CO- between carbon-carbon bonds in the substituted or unsubstituted divalent chain hydrocarbon group.

5. The liquid crystal alignment agent according to claim 2, wherein, B in equation (2) 1 and B 2 A monovalent group consisting independently of a hydrogen atom, a monovalent hydrocarbon group, a monovalent halide hydrocarbon group, or a monovalent hydrocarbon group or a monovalent halide hydrocarbon group containing -O- between carbon-carbon bonds.

6. The liquid crystal alignment agent according to claim 1, wherein, The addition polymer [P] further comprises a structural unit [C] having a partial structure represented by the following formula (3) and being different from the structural unit [A] and the structural unit [B]; * 3 -CO-OR 2 …(3) In equation (3), R 2 It is a monovalent straight-chain hydrocarbon group; 3 "" indicates a bond with the carbon atoms that make up the main chain of the polymer.

7. The liquid crystal alignment agent according to claim 1, further comprising at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide.

8. The liquid crystal alignment agent according to claim 1, further comprising a crosslinking agent.

9. The liquid crystal alignment agent according to claim 8, wherein, The crosslinking agent does not have an aromatic ring.

10. The liquid crystal alignment agent according to claim 1, used to form a weakly anchored liquid crystal alignment film.

11. A liquid crystal alignment film formed using a liquid crystal alignment agent as described in any one of claims 1 to 10.

12. A liquid crystal element comprising the liquid crystal alignment film as described in claim 11.

13. A method for manufacturing a liquid crystal element, the liquid crystal element comprising a pair of substrates including a first substrate and a second substrate, and a liquid crystal layer disposed between the pair of substrates, and the method for manufacturing the liquid crystal element comprising the following steps: A liquid crystal alignment film is formed by coating the surface of one of the pair of substrates with a liquid crystal alignment agent as described in any one of claims 1 to 10.

14. The method for manufacturing a liquid crystal element according to claim 13, wherein, The liquid crystal alignment film formed by the liquid crystal alignment agent according to any one of claims 1 to 10 is a weakly anchored liquid crystal alignment film. The manufacturing method of the liquid crystal element further includes the following steps: forming a strong anchoring liquid crystal alignment film with a stronger anchoring energy than the weak anchoring liquid crystal alignment film on the surface of a substrate that is different from the substrate on which the weak anchoring liquid crystal alignment film is formed in the first substrate and the second substrate.

15. The method for manufacturing a liquid crystal element according to claim 14, wherein, The strongly anchored liquid crystal alignment film is a rubbing alignment film or a photoalignment film.

16. The method for manufacturing a liquid crystal element according to claim 14, wherein, The first substrate has a pair of electrodes, while the second substrate does not have electrodes. The strongly anchored liquid crystal alignment film is formed on the surface of the first substrate. The weakly anchored liquid crystal alignment film is formed on the surface of the second substrate.

Images