Liquid crystal aligning agent for forming weak anchor film, method for manufacturing liquid crystal alignment film, and method for manufacturing liquid crystal element

Abstract

The invention provides a liquid crystal alignment agent for forming a weak anchor film, a method for manufacturing a liquid crystal alignment film, and a method for manufacturing a liquid crystal element, which can obtain a liquid crystal element with excellent liquid crystal alignment property, can realize low-voltage driving of the liquid crystal element, and can form a liquid crystal alignment film with excellent sealing property. A liquid crystal aligning agent for forming a weak anchor film, the liquid crystal aligning agent for forming a weak anchor film being used for forming a weak anchor liquid crystal aligning film, the liquid crystal aligning agent for forming a weak anchor film comprising: a polymer having an aliphatic ring having 7 or more ring elements in a side chain; and a crosslinking agent.

Description

Technical Field

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

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

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

[0004] [Prior Art Documents]

[0005] [Patent Documents]

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

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

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

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

[0010] The present invention has been made in view of the above problems, and a main object thereof is to provide a liquid crystal aligning agent that can obtain a liquid crystal element having excellent liquid crystal alignment properties, can achieve low voltage driving of the liquid crystal element, and can form a liquid crystal alignment film having excellent close contact properties.

[0011] [Means for Solving the Problems]

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

[0013] [1] A liquid crystal aligning agent for forming a weak anchoring film, which is used to form a weak anchoring liquid crystal alignment film, and the liquid crystal aligning agent for forming a weak anchoring film contains: a polymer (P) having an aliphatic ring with 7 or more ring members in a side chain; and a crosslinking agent.

[0014] [2] A method for manufacturing a liquid crystal alignment film, which uses the liquid crystal aligning agent according to the above [1] to form a weak anchoring liquid crystal alignment film.

[0015] [3] A method for manufacturing a liquid crystal element, wherein the liquid crystal element includes 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 includes the following steps: applying the liquid crystal aligning agent for forming a weak anchoring film according to the above [1] to the surface of at least one of the first substrate and the second substrate to form a weak anchoring liquid crystal alignment film.

[0016] [Effects of the Invention]

[0017] According to the liquid crystal aligning agent of the present invention, a liquid crystal element having excellent liquid crystal alignment properties can be obtained, and at the same time, low voltage driving of the liquid crystal element can be achieved. In addition, according to the liquid crystal aligning agent of the present invention, a liquid crystal alignment film having excellent close contact properties can be formed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of an FFS type liquid crystal display element.

[0019] Figure 2 of (a),Figure 2 Fig. (b) is a plan view of the top electrode for manufacturing a liquid crystal display element. Figure 2 Fig. (a) is a top view of the top electrode, Figure 2 Fig. (b) is a partially enlarged view of the top electrode.

[0020] Figure 3 is a diagram showing the drive electrodes of a four-system.

[0021] [Description of symbols]

[0022] 10: FFS type liquid crystal display element

[0023] 11a, 11b: Glass substrates

[0024] 12: Liquid crystal alignment film

[0025] 13: Top electrode

[0026] 14: Insulating layer

[0027] 15: Bottom electrode

[0028] 16: Liquid crystal layer

[0029] C1: Portion surrounded by a dotted line

[0030] d1: Line width of the electrode

[0031] d2: Distance between electrodes Detailed implementation mode

[0032] Hereinafter, matters related to the embodiments will be described in detail. In addition, in this specification, the numerical range described using "~" means that the numerical values described before and after "~" are included as the lower limit value and the upper limit value. A "structural unit" is a unit that mainly constitutes the main chain structure, and means a unit that includes two or more units at least in the main chain structure. A structural unit is typically a repeating unit formed based on a single monomer.

[0033] In this specification, the so-called "hydrocarbyl group" means a group including an acyclic hydrocarbyl group, an alicyclic hydrocarbyl group, and an aromatic hydrocarbyl group. The so-called "acyclic hydrocarbyl group" means a straight-chain or branched hydrocarbyl group in which the main chain does not contain a cyclic structure but only an acyclic structure. Among them, the acyclic hydrocarbyl group can be saturated or unsaturated. The so-called "alicyclic hydrocarbyl group" means a hydrocarbyl group in which the ring structure contains only an alicyclic hydrocarbon structure and does not contain an aromatic ring structure. Among them, the alicyclic hydrocarbyl group does not need to include only the alicyclic hydrocarbon structure, and also includes a group having an acyclic structure in a part thereof. The so-called "aromatic hydrocarbyl group" means a hydrocarbyl group including an aromatic ring structure as the ring structure. Among them, the aromatic hydrocarbyl group does not need to include only the aromatic ring structure, and may also include an acyclic structure or an alicyclic hydrocarbon structure in a part thereof. The so-called "organic group" means an atomic group formed by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound).

[0034] The so-called "main chain" of a polymer means the "main trunk" part of the polymer that contains the longest chain of atoms. The part of the so-called "main trunk" is allowed to contain a cyclic structure. For example, the so-called "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. The so-called "side chain" means a part branched from the part of the "main trunk" of the polymer. "(Meth)acryloyl group" is a term including an acryloyl group and a methacryloyl group, and "(meth)acryloyl" is a term including an acryloyl and a methacryloyl. "(Meth)acrylate" is a term including an acrylate and a methacrylate.

[0035] "Liquid Crystal Alignment Agent"

[0036] The liquid crystal alignment agent of the present disclosure is a liquid crystal alignment agent for forming a weak anchoring liquid crystal alignment film for forming a weak anchoring film. The liquid crystal alignment agent of the present disclosure contains: a polymer (P) having an aliphatic ring with 7 or more ring members in the side chain; and a crosslinking agent. Hereinafter, each component will be described in detail. In addition, regarding each component, unless otherwise specifically mentioned, one kind can be used alone, or two or more kinds can be used in combination.

[0037] <Polymer (P)>

[0038] Examples of the aliphatic ring having 7 or more ring members possessed by the polymer (P) include an aliphatic hydrocarbon ring having 7 to 30 carbon atoms and an aliphatic heterocyclic ring having 7 to 30 carbon atoms. These aliphatic rings can be saturated or unsaturated. In addition, the aliphatic ring having 7 or more ring members possessed by the polymer (P) can be either a bridged type or a condensed ring type, or a combination of a bridged type and a condensed ring type. The aliphatic ring having 7 or more ring members possessed by the polymer (P) can have a substituent.

[0039] As the aliphatic hydrocarbon ring having 7 to 30 carbon atoms, a monocyclic aliphatic hydrocarbon ring having 7 to 30 carbon atoms and a polycyclic aliphatic hydrocarbon ring having 7 to 30 carbon atoms can be mentioned. As specific examples of the monocyclic aliphatic hydrocarbon ring, the following can be mentioned: saturated hydrocarbon rings such as cycloheptane, cyclooctane, cyclononane, cyclodecane, cycloundecane, cyclododecane, cyclotridecane, cyclotetradecane, cyclopentadecane, cyclohexadecane, cycloheptadecane, cyclooctadecane, cyclononadecane, cycloeicosane, cyclodocosane; unsaturated hydrocarbon rings such as cycloheptene, cyclooctene, cyclodecene, cyclododecene, cyclotridecene, cyclopentadecene, cyclohexadecene, cycloheptadecene, cyclooctadecene. The polycyclic aliphatic hydrocarbon ring is preferably a bridged saturated aliphatic hydrocarbon ring or a fused saturated aliphatic hydrocarbon ring. For example, bicyclo[3.2.1]octane, tricyclo[3.2.1.0 2,7 octane, etc. can be mentioned.

[0040] In addition, when the aliphatic ring is polycyclic, regarding the "aliphatic ring having 7 or more ring members", in the structure, there is one or more aliphatic rings having 7 or more ring members. That is, in the case of a fused-ring aliphatic ring, at least one of the two or more rings constituting the fused ring has 7 or more ring members. In addition, in the case of a bridged aliphatic ring, the bridged alicyclic skeleton contains a ring having 7 or more ring members. Therefore, for example, a fused ring including only aliphatic rings having 6 or less ring members such as decalin or bicyclo[4.3.0]nonane, or a bridged ring such as norbornane or bicyclo[2.2.2]octane that does not contain an aliphatic ring having 7 or more ring members in the alicyclic skeleton does not conform to the "aliphatic ring having 7 or more ring members".

[0041] As the aliphatic heterocyclic ring having 7 to 30 carbon atoms, a ring in which any methylene group of the rings exemplified as the aliphatic hydrocarbon ring having 7 to 30 carbon atoms is substituted with -O-, -S-, -CO-, -NR- (wherein R is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms) can be mentioned. The aliphatic heterocyclic ring can be either monocyclic or polycyclic. As specific examples of the aliphatic heterocyclic ring having 7 to 30 carbon atoms, the following can be mentioned: nitrogen-containing monocyclic saturated aliphatic heterocyclic rings such as azacyclooctane, azacyclononane; nitrogen-containing monocyclic unsaturated aliphatic heterocyclic rings such as 2,3-dihydroazepine, 2,5-dihydroazepine, 4,5-dihydroazepine; nitrogen-containing polycyclic aliphatic heterocyclic rings such as tropane, nortropane; oxygen-containing monocyclic saturated aliphatic heterocyclic rings such as oxacycloheptane; sulfur-containing monocyclic saturated aliphatic heterocyclic rings such as thiacyclooctane; cyclic lactones such as ε-caprolactone; cyclic lactams such as ε-caprolactam; crown ethers such as 12-crown-4-ether, 15-crown-5-ether, 18-crown-6-ether, 1-aza-18-crown-6-ether, 4,13-diaza-18-crown-6-ether, etc.

[0042] When the aliphatic ring having 7 or more ring members in the polymer (P) has a substituent, examples of the substituent include: an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), a hydroxyl group, a cyano group, a nitro group, an acyl group, etc.

[0043] From the viewpoint of obtaining a liquid crystal alignment film exhibiting good weak anchoring properties, the polymer (P) preferably has a group formed by removing one hydrogen atom from an aliphatic ring having 7 or more ring members. Specifically, the polymer (P) preferably has a partial structure represented by the following formula (1).

[0044] *-L 1 -A 1 ···(1)

[0045] (In formula (1), L 1 is a single bond or a divalent linking group. A 1 is a group formed by removing one hydrogen atom from an aliphatic ring having 7 or more ring members. "*" represents a bonding site to the main chain)

[0046] In the formula (1), examples of the divalent linking group represented by L 1 include: -O-, -CO-, -COO-, -CONR 1 -(wherein R 1 is a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms or a monovalent thermally dissociable group), a divalent hydrocarbon group having 1 to 20 carbon atoms, a divalent group in which any methylene group of the hydrocarbon group is substituted with -O-, -CO-, -COO- or -CONR 1 -, etc. The divalent linking group represented by L 1 may be substituted with a hydrogen atom bonded to a carbon atom of the exemplified group. Examples of the substituent include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), a hydroxyl group, etc.

[0047] Examples of the monovalent thermally dissociable group represented by R 1 include: tert-butoxycarbonyl (Boc group), benzyloxycarbonyl, 1,1-dimethyl-2-haloethyloxycarbonyl, allyloxycarbonyl, 2-(trimethylsilyl)ethyloxycarbonyl, 9-fluorenylmethyloxycarbonyl, etc. Among these, from the viewpoint of excellent thermal dissociability and reduction of the residual amount of the dissociating structure in the film, the Boc group is particularly preferred.

[0048] The bonding site represented by "*" in the formula (1) is preferably bonded to a carbon atom or a nitrogen atom constituting the main chain. The bonding site may be bonded to a chain structure or a ring structure (for example, a benzene ring, a maleimide ring, a succinimide ring, etc.).

[0049] In terms of further improving the effect of low-voltage driving of the liquid crystal element, the number of ring members of the aliphatic ring in the polymer (P) is preferably 7 to 18, more preferably 7 to 15, further preferably 8 to 15, and still more preferably 8 to 12. Further, for the same reason, the aliphatic ring having 7 or more ring members in the polymer (P) is preferably an aliphatic hydrocarbon ring or a nitrogen-containing aliphatic heterocyclic ring, and more preferably an aliphatic hydrocarbon ring.

[0050] From the viewpoint of obtaining a liquid crystal alignment film showing good weak anchoring properties, the polymer (P) is preferably a polymer containing a structural unit having an aliphatic ring with 7 or more ring members. In the polymer (P), the proportion of the structural unit having an aliphatic ring with 7 or more ring members is preferably 15 mol% or more, more preferably 30 mol% or more, and further preferably 50 mol% or more, based on the total amount of the structural units constituting the polymer (P).

[0051] The main chain of the polymer (P) is not particularly limited. Examples of the main chain of the polymer (P) include: addition polymers, polyamic acids, polyamic acid esters, polyimides, polyamides, polyamideimides, polyorganosiloxanes, polyesters, polyenamines, polyureas, polybenzoxazoles, etc. From the viewpoints of excellent voltage holding characteristics or liquid crystal alignment properties of the obtained liquid crystal element and ease of introducing an aliphatic ring having 7 or more ring members into the side chain, the polymer (P) is preferably at least one selected from the group consisting of addition polymers, polyamic acids, polyamic acid esters, polyimides, and polyorganosiloxanes. Hereinafter, each polymer will be described in detail.

[0052] (Addition polymer)

[0053] Regarding the addition polymer as the polymer (P) (hereinafter, also referred to as "addition polymer (P)"), examples include: (meth)acrylic polymers, styrene polymers, maleimide polymers, (meth)acrylic-styrene copolymers, (meth)acrylic-maleimide copolymers, (meth)acrylic-styrene-maleimide copolymers, and styrene-maleimide copolymers. From the viewpoint of obtaining a liquid crystal alignment film showing good weak anchoring properties, the addition polymer (P) is preferably a polymer containing a structural unit having an aliphatic ring with 7 or more ring members. Specifically, it is preferably at least one selected from the group consisting of the structural unit represented by the following formula (2-1) and the structural unit represented by the following formula (2-2).

[0054] [Chemical formula 1]

[0055]

[0056] (In formula (2-1), R 11 is a hydrogen atom or a methyl group. X1 is -CO-, -COO-, -CONH- or a divalent aromatic ring group. X 2 is a single bond or a divalent linking group. A 1 is a group formed by removing one hydrogen atom from an aliphatic ring having 7 or more ring members.

[0057] In formula (2-2), R 12 and R 13 are each independently a hydrogen atom or a methyl group. X 3 is a divalent linking group. A 1 is a group formed by removing one hydrogen atom from an aliphatic ring having 7 or more ring members)

[0058] In the above formulas (2-1) and (2-2), when the group represented by X 1 is a divalent aromatic ring group, as the divalent aromatic ring group, it is preferably a group formed by removing two hydrogen atoms from a benzene ring or a naphthalene ring. The aromatic ring group may have a substituent in the ring portion. As the substituent, the same groups as those exemplified as the substituents that an aliphatic ring having 7 or more ring members may have can be cited.

[0059] As X 2 or X 3 The divalent linking group represented may include a divalent hydrocarbon group having 1 to 20 carbon atoms, a divalent group in which any methylene group of the hydrocarbon group is substituted by -O-, -CO-, -COO- or -CONR 1 -. These divalent linking groups may also have a hydrogen atom bonded to a carbon atom substituted. As the substituent, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), a hydroxyl group, etc. can be cited.

[0060] In terms of easily introducing an aliphatic ring having 7 or more ring members into the side chain, the addition polymer (P) preferably contains a structural unit derived from a monomer having an aliphatic ring having 7 or more ring members. Specific examples of the monomer providing a structural unit having an aliphatic hydrocarbon ring having 7 or more ring members include compounds represented by the following formulas (2-1-1) to (2-1-9) respectively. Specific examples of the monomer providing a structural unit having an aliphatic heterocycle having 7 or more ring members include compounds represented by the following formulas (2-2-1) to (2-2-6) respectively.

[0061] [Chemical formula 2]

[0062]

[0063] (In the formula, R a is a hydrogen atom or a methyl group)

[0064] exhibits excellent liquid crystal alignment properties (especially alternating current (AC) afterimage characteristics), and in terms of further improving the effect of low-voltage driving of liquid crystal elements, the monomer having an aliphatic ring with 7 or more ring members is preferably a compound having none of an amide group, a hydroxyl group, an amino group, and a protected amino group. Specifically, among the compounds represented by the formulas (2-1-1) to (2-1-9) and the formulas (2-2-1) to (2-2-6), the compounds represented by the formulas (2-1-2) to (2-1-5), the formulas (2-1-7) to (2-1-9), and the formula (2-2-3) are preferred.

[0065] When synthesizing the addition polymer (P), a monomer having no aliphatic ring with 7 or more ring members (hereinafter, also referred to as "other monomer") can also be used together with the monomer having an aliphatic ring with 7 or more ring members. Examples of other monomers include: (meth)acrylic compounds, styrene compounds, conjugated diene compounds, maleimide compounds, etc.

[0066] Regarding specific examples of other monomers, as (meth)acrylic compounds, examples include: unsaturated carboxylic acids such as (meth)acrylic acid; (meth)acrylic acid alkyl esters (for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.), cycloalkyl (meth)acrylate, benzyl (meth)acrylate, trimethoxysilylpropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 4-hydroxybutyl glycidyl ether (meth)acrylate, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 6-(meth)acryloyloxyhexyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, and 3-(meth)acryloyloxypropylmethyldiethoxysilane, etc. unsaturated carboxylic acid esters.

[0067] Examples of the styrene compound include styrene, methylstyrene, divinylbenzene, 4-hydroxymethylstyrene, p-styryltrimethoxysilane, 4-(glycidyloxymethyl)styrene, and vinylbenzoic acid. Examples of the conjugated diene compound include 1,3-butadiene and 2-methyl-1,3-butadiene. Examples of the maleimide compound include N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(4-glycidyloxyphenyl)maleimide, N-(4-glycidyloxymethylphenyl)maleimide, N-glycidylmaleimide, N-(4-carboxyphenyl)maleimide, and N-(4-tert-butoxycarbonylphenyl)maleimide.

[0068] In addition, as other monomers, compounds other than those described above can also be used, which are unsaturated monomers containing a photo-orienting group (e.g., a cinnamate structure, a coumarin structure, an azobenzene structure), an alkyl group having 4 to 30 carbon atoms, a halogenated alkyl group having 4 to 30 carbon atoms, an alkoxy group having 4 to 30 carbon atoms, a halogenated alkoxy group having 4 to 30 carbon atoms, a structure in which one or more rings among a benzene ring and a cyclohexane ring are linked by a single bond or a linking group, or a group having a steroid skeleton.

[0069] In the addition polymer (P), in terms of sufficiently achieving low-voltage driving and obtaining a liquid crystal element showing excellent liquid crystal alignment, the proportion of the structural unit having an aliphatic ring with 7 or more ring members is preferably 20 mol% or more, more preferably 30 mol% or more, and further preferably 50 mol% or more, based on the total amount of the structural units constituting the addition polymer (P).

[0070] In terms of improving the effect of low-voltage driving of the liquid crystal element, the addition polymer (P) preferably contains a structural unit derived from a (meth)acrylic acid-based compound. In the addition polymer (P), the proportion of the structural unit derived from the (meth)acrylic acid-based compound is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 20 mol% or more, based on the total amount of the structural units constituting the addition polymer (P).

[0071] The addition polymer (P) can be obtained, for example, by polymerizing monomers in the presence of a polymerization initiator. As the polymerization initiator used, azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) are preferred. The use ratio of the polymerization initiator is preferably set to 0.01 part by mass to 30 parts by mass with respect to 100 parts by mass of all the monomers used in the reaction.

[0072] The polymerization reaction is preferably carried out in an organic solvent. Examples of the organic solvent used in the reaction include alcohols, ethers, ketones, amides, esters, hydrocarbon compounds, etc., and diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether acetate, etc. are preferred. The reaction temperature is preferably set at 30°C to 120°C, and the reaction time is preferably set at 1 hour to 36 hours. The amount of the organic solvent used is preferably set such that the total amount of the monomers used in the reaction is 0.1% by mass to 60% by mass relative to the total amount of the reaction solution. In addition, the addition polymer (P) can also be obtained by the following method: synthesizing an addition polymer having an epoxy group in the side chain, and then reacting the obtained epoxy group-containing addition polymer with a carboxylic acid having an aliphatic ring with 7 or more ring members (hereinafter, also referred to as "specific carboxylic acid").

[0073] For the addition polymer (P), the polystyrene-reduced weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) is preferably 250 to 500,000, more preferably 500 to 100,000. In addition, the molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the polystyrene-reduced number average molecular weight (Mn) measured by GPC is preferably 8 or less, more preferably 6 or less.

[0074] (Polyamic acid)

[0075] The polyamic acid (hereinafter, also referred to as "polyamic acid (P)") as the polymer (P) can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine compound.

[0076] · Tetracarboxylic dianhydride

[0077] Examples of the tetracarboxylic dianhydride used in the synthesis of the polyamic acid (P) include aliphatic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides. The aliphatic tetracarboxylic dianhydrides include chain tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides.

[0078] As specific examples of the chain-like tetracarboxylic dianhydride, for example, butanetetracarboxylic dianhydride can be cited. As specific examples of the alicyclic tetracarboxylic dianhydride, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 3-oxabicyclo[3.2.1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5-dioxotetrahydro-3-furyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic 2:4,6:8-dianhydride, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic 2:3,5:6-dianhydride, 4,9-dioxatricyclo 2,6 undecane-3,5,8,10-tetraone, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, ethylenediaminetetraacetic dianhydride, cyclopentanetetracarboxylic dianhydride, etc.

[0079] As the aromatic tetracarboxylic dianhydride, for example, pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, p-phenylenebis(trimellitic monoester anhydride), ethylene glycol bis(trimellitic anhydride ester), 1,3-propanediol bis(trimellitic anhydride ester), 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-biphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, etc. In addition, as the tetracarboxylic dianhydride used in the synthesis of the polyamic acid (P), in addition to the above, the tetracarboxylic dianhydride described in Japanese Patent Laid-Open No. 2010-97188 can be used.

[0080] ·Diamine compound

[0081] In the synthesis of the polyamic acid (P), in terms of the high degree of freedom in the selection of monomers, a diamine having an aliphatic ring with 7 or more ring members (hereinafter, also referred to as "specific diamine") can be preferably used. As a preferred specific example of the specific diamine, the compound represented by the following formula (3) can be cited.

[0082] [Chemical formula 3]

[0083]

[0084] (In formula (3), Ar 1An aromatic ring group having a valence of (2+r). r is an integer from 1 to 4. X 4 is -O-, -S-, -CO-, -COO-, -NR 2 -, -CO-NR 2 -, -CH 2 -O-, -CH 2 -CO- or -CH 2 -OCO-. X 5 is a single bond or a divalent linking group. R 2 is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or a monovalent thermally detachable group. A 1 is a group formed by removing one hydrogen atom from an aliphatic ring having 7 or more ring members. When there are multiple X 4 , X 5 , A 1 in the formula, multiple X 4 , X 5 , A 1 are the same or different)

[0085] In the formula (3), the aromatic ring group represented by Ar 1 is a group formed by removing (2+r) hydrogen atoms from an aromatic ring. The aromatic ring is preferably an aromatic hydrocarbon ring or a nitrogen-containing heterocyclic ring, more preferably a benzene ring, a naphthalene ring or a pyridine ring, and still more preferably a benzene ring. Ar 1 The aromatic ring group represented may have a substituent on the ring portion. As specific examples of the substituent, groups the same as those exemplified as the substituents that an aliphatic ring having 7 or more ring members may have can be cited.

[0086] As the divalent linking group represented by X 5 , groups the same as those exemplified as the specific examples of X 2 in the formula (2-1) and X 3 in the formula (2-2) can be cited.

[0087] As specific examples of the specific diamine, compounds represented by the following formulas (3-1) to (3-10) etc. can be cited. In addition, "Boc" in the structural formula represents tert-butoxycarbonyl (the same hereinafter).

[0088] [Chemical formula 4]

[0089]

[0090] The diamine compound used in the synthesis of polyamic acid (P) can be only a specific diamine. Additionally, as the diamine compound used in the synthesis of polyamic acid (P), a specific diamine and a diamine without an aliphatic ring having 7 or more ring members (hereinafter also referred to as "other diamine") can be used in combination. Examples of the other diamine include: aliphatic diamines, aromatic diamines, diaminoorganosiloxanes, etc. The aliphatic diamines include chain diamines and alicyclic diamines.

[0091] Regarding specific examples of the other diamine, as the chain diamine, for example, m-xylene diamine, 1,3-propanediamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, 1,3-bis(aminomethyl)cyclohexane, etc. can be cited; as the alicyclic diamine, for example, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), etc. can be cited;

[0092] As the aromatic diamine, for example, dodecyloxy diaminobenzene, tetradecyloxy diaminobenzene, pentadecyloxy diaminobenzene, hexadecyloxy diaminobenzene, octadecyloxy diaminobenzene, cholesteryloxy diaminobenzene, cholestenyloxy diaminobenzene, cholesteryl diamino benzoate, cholestenyl diamino benzoate, lanosteryl diamino benzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenoxy)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-(4-heptylcyclohexyl)cyclohexane, N-(2,4-diaminophenyl)-4-(4-heptylcyclohexyl)benzamide, diamines with an orientation group such as the compound represented by the following formula (E-1):

[0093] [Chemical formula 5]

[0094]

[0095] (In formula (E-1), X I and X II are each independently a single bond, -O-, *-COO- or *-OCO- (wherein, "*" represents the bonding bond to the diamino phenyl side). R I is an alkanediyl having 1 to 3 carbon atoms. R II is a single bond or an alkanediyl having 1 to 3 carbon atoms. R III is an alkyl, alkoxy, fluoroalkyl or fluoroalkoxy having 1 to 20 carbon atoms. a is 0 or 1. b is an integer from 0 to 3. c is an integer from 0 to 2. d is 0 or 1. Wherein, 1 ≤ a + b + c ≤ 3):

[0096] p-Phenylenediamine, 4,4'-Diaminodiphenylmethane, 4,4'-Diaminodiphenylamine, 4,4'-Diaminodiphenylsulfide, 4-Aminophenyl-4'-aminobenzoate, 4,4'-Diaminoazobenzene, 1,2-Bis(4-aminophenoxy)methane, 1,2-Bis(4-aminophenoxy)ethane, 1,3-Bis(4-aminophenoxy)propane, 1,5-Bis(4-aminophenoxy)pentane, 1,6-Bis(4-aminophenoxy)hexane, 1,7-Bis(4-aminophenoxy)heptane, Bis[2-(4-aminophenyl)ethyl]adipate, N,N-Bis(4-aminophenyl)methylamine, N,N'-Bis(5-amino-2-pyridyl)-N,N'-bis(tert-butoxycarbonyl)ethylenediamine, 4,4'-(2,2'-Oxydibis(ethane-2,1-diyl)bis(oxy))diphenylamine, 1,5-Diaminonaphthalene, 2,2'-Dimethyl-4,4'-diaminobiphenyl, 2,2'-Bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-Diaminodiphenyl ether, 2,2-Bis[4-(4-aminophenoxy)phenyl]propane, 9,9-Bis(4-aminophenyl)fluorene, 2,2-Bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-Bis(4-aminophenyl)hexafluoropropane, 4,4'-(p-Phenylenediisopropylidene)diphenylamine, 1,4-Bis(4-aminophenoxy)benzene, 4,4'-Bis(4-aminophenoxy)biphenyl, 2,6-Diaminopyridine, 2,4-Diaminopyrimidine, 3,6-Diaminoacridine, 3,6-Diaminocarbazole, N-Methyl-3,6-diaminocarbazole, N,N'-Bis(4-aminophenyl)-benzidine, N,N'-Bis(4-aminophenyl)-N,N'-dimethylbenzidine, 1,4-Bis-(4-aminophenyl)-piperazine, 3,5-Diaminobenzoic acid, Methyl 3,5-diaminobenzoate, Ethyl 3,5-diaminobenzoate, 1-(4-Aminophenoxy)-2-(4-(4'-aminophenyl)phenoxy)ethane, 3,5-Diamino-N,N-bis(pyridin-3-ylmethyl)benzamide, diamines represented by the following formulas (f-1) to (f-34), etc.;

[0097] [Chemical formula 6]

[0098]

[0099] [Chemical formula 7]

[0100]

[0101] Examples of the diaminoorganosiloxane include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, etc. In addition, diamines described in Japanese Patent Laid-Open No. 2010-97188 can be used.

[0102] As the divalent group represented by "-X I -(R I -X II ) d -", it is preferably an alkanediyl having 1 to 3 carbon atoms, *-O-, *-COO- or *-O-C 2 H 4 -O- (wherein the bonding site with "*" is bonded to the diaminophenyl). R III The group represented is preferably linear. The two amino groups in the diaminophenyl are preferably located at the 2,4-position or 3,5-position relative to the other groups.

[0103] As specific examples of the compound represented by the formula (E-1), for example, the compounds represented by the following formulas (E-1-1) to (E-1-4) can be cited respectively.

[0104] [Chemical Formula 8]

[0105]

[0106] When synthesizing the polyamic acid (P), the use ratio of the specific diamine is preferably 30 mol% or more, more preferably 40 mol% or more, and still more preferably 50 mol% or more, based on the total amount of the diamine compounds used in the synthesis of the polyamic acid (P). If the use ratio of the specific diamine is within the above range, low-voltage driving of the liquid crystal element can be achieved, and at the same time, a liquid crystal element with excellent liquid crystal alignment can be obtained, which is preferable in this regard.

[0107] ·Synthesis of polyamic acid

[0108] The polyamic acid (P) can be obtained by reacting a tetracarboxylic dianhydride as described above with a diamine compound and, if necessary, a molecular weight adjuster. The use ratio of the tetracarboxylic dianhydride and the diamine compound in the synthesis reaction of the polyamic acid (P) is preferably such that the acid anhydride group of the tetracarboxylic dianhydride is 0.2 equivalents to 2 equivalents relative to 1 equivalent of the amino group of the diamine compound, and more preferably such that the acid anhydride group of the tetracarboxylic dianhydride is 0.3 equivalents to 1.2 equivalents relative to 1 equivalent of the amino group of the diamine compound.

[0109] As the molecular weight adjuster, for example, acid monohydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate, etc. can be cited. The use ratio of the molecular weight adjuster is preferably set to 20 parts by mass or less, and more preferably set to 10 parts by mass or less, based on the total 100 parts by mass of the tetracarboxylic dianhydride and the diamine compound used.

[0110] The synthesis reaction of polyamic acid (P) is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20°C to 150°C, more preferably 0°C to 100°C. In addition, the reaction time is preferably 0.1 hour to 24 hours, more preferably 0.5 hour to 12 hours.

[0111] Examples of the organic solvent used in the reaction include: aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc. Among these organic solvents, it is preferred to use one or more selected from the group consisting of aprotic polar solvents and phenolic solvents (organic solvents of the first group), or a mixture of one or more selected from the organic solvents of the first group and one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (organic solvents of the second group). In the latter case, the usage ratio of the organic solvent of the second group is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less, relative to the total amount of the organic solvents of the first group and the second group.

[0112] Particularly preferred organic solvents are preferably one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphoric triamide, m-cresol, xylenol and halogenated phenols as solvents, or a mixture of one or more of these within the above-mentioned ratio range and other organic solvents. The usage amount (x) of the organic solvent is preferably set such that the total amount (y) of the tetracarboxylic dianhydride and the diamine compound is 0.1% by mass to 50% by mass relative to the total amount (x + y) of the reaction solution.

[0113] As described above, a reaction solution in which polyamic acid (P) is dissolved is obtained. The reaction solution can be directly used for the preparation of a liquid crystal aligning agent, or can be used for the preparation of a liquid crystal aligning agent after separating the polyamic acid (P) contained in the reaction solution, or can be used for the preparation of a liquid crystal aligning agent after refining the separated polyamic acid (P). In the case of dehydrating and cyclizing polyamic acid (P) to form polyimide, the reaction solution can be directly used for the dehydrating and cyclizing reaction, or can be used for the dehydrating and cyclizing reaction after separating the polyamic acid (P) contained in the reaction solution, or can be used for the dehydrating and cyclizing reaction after refining the separated polyamic acid (P). The separation and refining of polyamic acid (P) can be carried out according to known methods.

[0114] (Polyamic acid ester)

[0115] The polyamic acid ester as the polymer (P) can be obtained, for example, by the following methods: [I] a method of reacting the polyamic acid (P) obtained by the synthesis reaction with an esterifying agent; [II] a method of reacting a tetracarboxylic acid diester with a diamine compound; [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine compound.

[0116] In addition, in this specification, the so-called "tetracarboxylic acid diester" refers to a compound in which two of the four carboxyl groups of the tetracarboxylic acid are esterified and the remaining two are carboxyl groups. The so-called "tetracarboxylic acid diester dihalide" refers to a compound in which two of the four carboxyl groups of the tetracarboxylic acid are esterified and the remaining two are halogenated.

[0117] Examples of the esterifying agent used in method [I] include: hydroxy-containing compounds, acetal compounds, halides, epoxy group-containing compounds, etc. Specific examples of these are, as hydroxy-containing compounds, for example: alcohols such as methanol, ethanol, and propanol, phenols such as phenol and cresol, etc.; as acetal compounds, for example, N,N-dimethylformamide diethyl acetal, N,N-diethylformamide diethyl acetal, etc.; as halides, for example: methyl bromide, ethyl bromide, octadecyl bromide, methyl chloride, octadecyl chloride, 1,1,1-trifluoro-2-iodoethane, etc.; as epoxy group-containing compounds, for example, propylene oxide, etc.

[0118] The tetracarboxylic acid diester used in method [II] can be obtained, for example, by the following method: using an alcohol such as methanol or ethanol to ring-open the tetracarboxylic dianhydride exemplified in the description of the synthesis of the polyamic acid (P). In addition, tetracarboxylic dianhydride can also be used in combination in method [II]. Regarding the diamine compound, the specific diamine exemplified in the synthesis of the polyamic acid can be used alone, or other diamines can also be used in combination.

[0119] The reaction of method [II] is preferably carried out in an organic solvent in the presence of a suitable dehydration catalyst. Examples of the organic solvent include the organic solvents exemplified in the synthesis of the polyamic acid (P). Examples of the dehydration catalyst include: 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium halide, carbonylimidazole, phosphorus-based condensing agents, etc. The reaction temperature at this time is preferably -20°C to 150°C, more preferably 0°C to 100°C. The reaction time is preferably 0.1 hour to 24 hours, more preferably 0.5 hour to 12 hours.

[0120] The tetracarboxylic acid diester dihalide used in Method [III] can be obtained, for example, by reacting the tetracarboxylic acid diester obtained as described above with a suitable chlorinating agent such as thionyl chloride. In addition, a tetracarboxylic dianhydride can also be used in combination in Method [III]. Regarding the diamine compound, the specific diamines exemplified in the description of the synthesis of polyamic acid (P) can be used alone, or other diamines can also be used in combination.

[0121] The reaction of Method [III] is preferably carried out in an organic solvent in the presence of a suitable base. As the organic solvent, the organic solvents exemplified as the organic solvents used in the synthesis of polyamic acid (P) can be cited. As the base, for example, tertiary amines such as pyridine and triethylamine; alkali metals such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium, and potassium can be preferably used. The reaction temperature at this time is preferably -20°C to 150°C, more preferably 0°C to 100°C. The reaction time is preferably 0.1 hour to 24 hours, more preferably 0.5 hour to 12 hours.

[0122] The polyamic acid ester contained in the liquid crystal aligning agent may have only an amic acid ester structure, or may be a partial ester in which an amic acid structure and an amic acid ester structure coexist. In addition, the reaction solution obtained by dissolving the polyamic acid ester can be directly used for the preparation of the liquid crystal aligning agent, or can be used for the preparation of the liquid crystal aligning agent after separating the polyamic acid ester contained in the reaction solution, or can be used for the preparation of the liquid crystal aligning agent after refining the separated polyamic acid ester. The separation and refining of the polyamic acid ester can be carried out according to known methods.

[0123] (Polyimide)

[0124] The polyimide as the polymer (P) can be obtained, for example, by subjecting the polyamic acid (P) synthesized as described above to dehydration ring closure and imidization.

[0125] The polyimide can be a completely imidized product obtained by subjecting all of the amic acid structures of the polyamic acid as its precursor to dehydration ring closure, or can be a partially imidized product in which only a part of the amic acid structure is subjected to dehydration ring closure to coexist an amic acid structure and an imide ring structure. The imidization rate of the polyimide used in the reaction is preferably 20% or more, more preferably 30% to 99%, and further preferably 40% to 99%. The imidization rate is expressed as a percentage of the proportion of the number of imide ring structures relative to the total number of amic acid structures and imide ring structures of the polyimide. Here, a part of the imide ring can be an isoimide ring.

[0126] The dehydration ring closure of polyamic acid is preferably carried out by heating the polyamic acid or by dissolving the polyamic acid in an organic solvent and adding a dehydrating agent and a dehydration ring closure catalyst to the solution and heating as required.

[0127] In the method of adding a dehydrating agent and a dehydration ring closure catalyst to a solution of polyamic acid, as the dehydrating agent, for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. The usage amount of the dehydrating agent is preferably set to 0.01 mol to 20 mol relative to 1 mol of the amic acid structure of polyamic acid. As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, triethylamine, and 1-methylpiperidine can be used. The usage amount of the dehydration ring closure catalyst is preferably set to 0.01 mol to 10 mol relative to 1 mol of the dehydrating agent used. As the organic solvent used in the dehydration ring closure reaction, the organic solvents exemplified as the organic solvents used in the synthesis of polyamic acid can be cited. The reaction temperature of the dehydration ring closure reaction is preferably 0°C to 180°C, more preferably 10°C to 150°C. The reaction time is preferably 1.0 hour to 120 hours, more preferably 2.0 hours to 30 hours.

[0128] As described above, a reaction solution containing polyimide is obtained. The reaction solution can be directly used for the preparation of a liquid crystal aligning agent, or can be used for the preparation of a liquid crystal aligning agent after removing the dehydrating agent and the dehydration ring closure catalyst from the reaction solution, or can be used for the preparation of a liquid crystal aligning agent after separating the polyimide, or can be used for the preparation of a liquid crystal aligning agent after refining the separated polyimide. These refining operations can be carried out according to known methods. In addition, polyimide can also be obtained by the imidization of polyamic acid ester.

[0129] Regarding the polyamic acid, polyamic acid ester, and polyimide obtained as the polymer (P) as described above, it is preferable that when a 15 mass% solution is prepared, it has a solution viscosity of 20 mPa·s to 1,800 mPa·s, and more preferably has a solution viscosity of 50 mPa·s to 1,500 mPa·s. In addition, the solution viscosity (mPa·s) of the polymer is a value measured at 25°C using an E-type rotational viscometer for a 15 mass% polymer solution prepared using a good solvent for the polymer (such as γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0130] The polystyrene-reduced weight average molecular weight (Mw) of the polyamic acid, polyamic acid ester, and polyimide as the polymer (P), measured by gel permeation chromatography (GPC), is preferably from 1,000 to 500,000, more preferably from 2,000 to 300,000. Further, for the polyamic acid, polyamic acid ester, and polyimide as the polymer (P), the molecular weight distribution (Mw / Mn), represented by the ratio of Mw to the number average molecular weight (Mn) of polystyrene measured by GPC, is preferably 8 or less, more preferably 5 or less. By having the Mw and Mw / Mn of the polyamic acid, polyamic acid ester, and polyimide as the polymer (P) within the above ranges, good liquid crystal alignment properties of the liquid crystal element can be ensured.

[0131] (Polyorganosiloxane)

[0132] The production method of the polyorganosiloxane as the polymer (P) (hereinafter also referred to as "polyorganosiloxane (P)") is not particularly limited as long as a polymer having an aliphatic ring with 7 or more ring members in the side chain can be obtained. Specifically, the following methods [1s] and [2s] can be mentioned.

[0133] [1s] A method in which a hydrolyzable silane compound (ms-1) having an epoxy group, or a mixture of the silane compound (ms-1) and other silane compounds, is subjected to hydrolysis and condensation to synthesize an epoxy group-containing polyorganosiloxane, and then the obtained epoxy group-containing polyorganosiloxane is reacted with a carboxylic acid (specific carboxylic acid) having an aliphatic ring with 7 or more ring members.

[0134] [2s] A method in which a hydrolyzable silane compound (ms-2) having an aliphatic ring with 7 or more ring members, or a mixture of the silane compound (ms-2) and other silane compounds, is subjected to hydrolysis and condensation.

[0135] Among these, the method [1s] is preferred in terms of simplicity and the aspect of increasing the introduction rate of the aliphatic ring with 7 or more ring members in the polyorganosiloxane (P).

[0136] As specific examples of the silane compound (ms-1), for example, the following can be cited: 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethylmethyldimethoxysilane, 2-glycidoxyethyldimethylmethoxysilane, 2-glycidoxyethyldimethylethoxysilane, 4-glycidoxybutyltrimethoxysilane, 4-glycidoxybutylmethyldimethoxysilane, 4-glycidoxybutylmethyldiethoxysilane, 4-glycidoxybutyldimethylmethoxysilane, 4-glycidoxybutyldimethylethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(3,4-epoxycyclohexyl)propyltrimethoxysilane, and the like.

[0137] Other silane compounds used in the synthesis of the epoxy group-containing polyorganosiloxane are not particularly limited as long as they are hydrolyzable silane compounds. As specific examples, for example, the following can be cited: alkoxysilanes such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane;

[0138] alkoxysilanes containing nitrogen / sulfur atoms such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(3-cyclohexylamino)propyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane;

[0139] alkoxysilanes containing unsaturated hydrocarbons such as 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 6-(meth)acryloyloxyhexyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane; trimethoxysilylpropyl succinic anhydride, and the like.

[0140] The hydrolysis / condensation reaction of the silane compound can be carried out by reacting one or more of the silane compounds with water, preferably in the presence of a suitable catalyst and an organic solvent. During the reaction, the usage ratio of water is preferably 1 mole to 30 moles relative to 1 mole of the silane compound (total amount). Examples of the catalyst used include acids, alkali metal compounds, organic bases, titanium compounds, zirconium compounds, etc. The usage amount of the catalyst varies depending on reaction conditions such as the type of catalyst and temperature, and can be appropriately set. The usage amount of the catalyst is preferably 0.01-fold mole to 3-fold moles relative to the total amount of the silane compound. Examples of the organic solvent used include hydrocarbons, ketones, esters, ethers, alcohols, etc. Among these, it is preferred to use a water-insoluble or poorly water-soluble organic solvent. The usage ratio of the organic solvent is preferably 10 parts by mass to 10,000 parts by mass relative to 100 parts by mass in total of the silane compounds used in the reaction.

[0141] The hydrolysis / condensation reaction is preferably carried out, for example, by heating using an oil bath or the like. At this time, the heating temperature is preferably set to 130 °C or lower, and the heating time is preferably set to 0.5 hour to 12 hours. After the reaction ends, if necessary, the organic solvent layer separated from the reaction solution is dried using a desiccant and then the solvent is removed, whereby the target polyorganosiloxane can be obtained. In addition, the synthesis method of the polyorganosiloxane is not limited to the hydrolysis / condensation reaction, and can be carried out, for example, by a method of reacting a hydrolyzable silane compound in the presence of oxalic acid and an alcohol.

[0142] In the method of [1s], the epoxy group-containing polyorganosiloxane obtained by the reaction is then reacted with a specific carboxylic acid. Thus, the epoxy group of the epoxy group-containing polyorganosiloxane reacts with the carboxyl group of the specific carboxylic acid, and a polyorganosiloxane (P) having an aliphatic ring with 7 or more ring members in the side chain can be obtained.

[0143] Specific examples of the specific carboxylic acid include, for example, compounds represented by the following formulas (4-1) to (4-6) respectively.

[0144] [Chemical formula 9]

[0145]

[0146] The content ratio of aliphatic rings having 7 or more ring members in one molecule of the polyorganosiloxane (P) is preferably 5 mol% or more, more preferably 20 mol% or more, and still more preferably 30 mol% or more, relative to the silicon atoms of the polyorganosiloxane (P). Further, the content ratio of aliphatic rings having 7 or more ring members in one molecule of the polyorganosiloxane (P) is preferably 90 mol% or less, more preferably 60 mol% or less, relative to the silicon atoms of the polyorganosiloxane (P). By the content ratio of aliphatic rings having 7 or more ring members in the polyorganosiloxane (P) being within the above range, low-voltage driving of the liquid crystal element can be sufficiently achieved, and at the same time, a liquid crystal element having excellent liquid crystal alignment can be obtained, which is preferable in this regard.

[0147] In addition, when synthesizing the polyorganosiloxane (P), the carboxylic acid used in the reaction with the epoxy group-containing polyorganosiloxane may be only a specific carboxylic acid, but a carboxylic acid having no aliphatic ring with 7 or more ring members (hereinafter, also referred to as "other carboxylic acid") may also be used in combination. Examples of the other carboxylic acid include compounds other than those described above, such as carboxylic acids containing a photoalignment group (e.g., cinnamate structure, coumarin structure, azobenzene structure), an alkyl group having 4 to 30 carbon atoms, a halogenated alkyl group having 4 to 30 carbon atoms, an alkoxy group having 4 to 30 carbon atoms, a halogenated alkoxy group having 4 to 30 carbon atoms, a structure in which one or more rings among a benzene ring and a cyclohexane ring are linked by a single bond or a linking group, a group having a polymerizable carbon-carbon unsaturated bond, or a group having a steroid skeleton.

[0148] The reaction of the epoxy group-containing polyorganosiloxane with the carboxylic acid is preferably carried out in the presence of a catalyst and an organic solvent. Examples of the catalyst used include organic bases and compounds known as so-called hardening accelerators that promote the reaction of epoxy compounds (e.g., tertiary organic amines, quaternary organic amines, quaternary ammonium salts, etc.). The amount of the catalyst used is preferably 100 parts by mass or less, more preferably 0.1 part by mass to 20 parts by mass, relative to 100 parts by mass of the epoxy group-containing polyorganosiloxane.

[0149] Examples of the organic solvent used in the reaction include hydrocarbons, ethers, esters, ketones, amides, alcohols, etc. The organic solvent is preferably used in a proportion such that the solid component concentration (the proportion of the total mass of the components other than the solvent in the reaction solution relative to the total weight of the solution) is 0.1% by mass or more, and more preferably in a proportion such that the solid component concentration (the proportion of the total mass of the components other than the solvent in the reaction solution relative to the total weight of the solution) is 5% to 50% by mass. In the reaction, the reaction temperature is preferably 0°C to 200°C, and more preferably 50°C to 150°C. The reaction time is preferably 0.1 hour to 50 hours, and more preferably 0.5 hour to 20 hours. After the reaction is completed, it is preferable to wash the organic solvent layer separated from the reaction solution with water. After washing with water, if necessary, the organic solvent layer is dried with an appropriate desiccant and then the solvent is removed, whereby the target polyorganosiloxane (P) can be obtained.

[0150] The polyorganosiloxane (P) preferably has a solution viscosity of 1 mPa·s to 500 mPa·s when made into a 10% by mass solution, and more preferably has a solution viscosity of 3 mPa·s to 200 mPa·s. For the polyorganosiloxane (P), the polystyrene-converted weight average molecular weight (Mw) measured by GPC is preferably 1,000 to 200,000, more preferably 2,000 to 50,000, and further preferably 3,000 to 20,000.

[0151] In terms of showing excellent liquid crystal alignment properties (especially the AC afterimage characteristics) and further improving the effect of low-voltage driving of the liquid crystal element, the polymer (P) is preferably an addition polymer as described above, and more preferably an addition polymer having no amide group, hydroxyl group, amino group, or protected amino group in the structural unit having an aliphatic ring with 7 or more ring members.

[0152] Relative to 100 parts by mass of the solid components (components other than the solvent of the liquid crystal aligning agent) contained in the liquid crystal aligning agent, the content ratio of the polymer (P) in the liquid crystal aligning agent of the present disclosure is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and further preferably 30 parts by mass or more.

[0153] <Crosslinking agent>

[0154] The liquid crystal aligning agent of the present disclosure contains a crosslinking agent together with the polymer (P). Thereby, low-voltage driving of the liquid crystal element can be achieved, and at the same time, a liquid crystal alignment film with excellent adhesion can be obtained. As the crosslinking agent, a compound having two or more crosslinkable groups selected from the group consisting of oxiranyl, protected oxiranyl, oxetanyl, mercapto group, protected mercapto group, carboxyl group, protected carboxyl group, acid anhydride group, hydroxyl group, protected hydroxyl group, amino group, protected amino group, protected isocyanate group, and a group having a polymerizable carbon-carbon bond in one molecule can be mentioned (wherein the polymer (P) is excluded).

[0155] From the viewpoint of obtaining a liquid crystal alignment film that exhibits good weak anchoring characteristics and excellent adhesion, the number of crosslinkable groups in one molecule of the crosslinking agent is preferably two to ten, more preferably two to six. In addition, the molecular weight of the crosslinking agent is preferably 100 to 1,000, more preferably 100 to 800, and still more preferably 100 to 600.

[0156] Regarding specific examples of the crosslinking agent, as compounds having an oxiranyl group, a protected oxiranyl group, or an oxetanyl group, examples include: ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, tris(2,3-epoxypropyl) isocyanurate, glycerol polyglycidyl ether, pentaerythritol tetraglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, N,N,N',N'-tetraglycidylglycoluril, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N-diglycidyl-benzylamine, N,N-diglycidyl-aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine, the epoxidation reaction product formed by hydrogen peroxide of 2,2'-diallylbisphenol A diallyl ether, the compounds represented by the following formulas (d1-1) and (d1-2), etc.

[0157] As compounds having a mercapto group or a protected mercapto group, examples include: 1,2-ethanedithiol, 1,3-propanedithiol, 1,3,4-thiadiazole-2,5-dithiol, 1,10-decanedithiol, pentaerythritol tetra(3-mercaptobutyrate), 1,3,5-tris(2-(3-mercaptobutyryloxy)ethyl)-1,3,5-triazacyclohexane-2,4,6-trione, etc.

[0158] Examples of the compound having a carboxyl group, a protected carboxyl group or an acid anhydride group include maleic acid, itaconic acid, trimellitic acid, tetracarboxylic acid, cis-1,2,3,4-tetrahydrophthalic acid, ethylene glycol bis(trimellitate), propylene glycol bis(trimellitate), 4,4'-oxybis(phthalic acid), trimellitic anhydride, etc.

[0159] As the compound having a hydroxyl group or a protected hydroxyl group, a compound having a hydroxymethyl group, a protected hydroxymethyl group, a hydroxyalkylamide group or a protected hydroxyalkylamide group is preferably used. Specific examples thereof include compounds represented by the following formula (d2-1) to formula (d2-6), formula (d3-1) to formula (d3-8), respectively.

[0160] Examples of the compound having an amino group or a protected amino group include compounds represented by the following formula (d4-1) to formula (d4-5), respectively.

[0161] Examples of the compound having a protected isocyanate group include tolylene diisocyanate, xylene diisocyanate, chlorobenzene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate or diphenylmethane diisocyanate in which the isocyanate group is protected by 3,6-dimethylpyrazole, methyl ethyl ketone oxime, diethyl malonate or ε-caprolactam, the compound represented by the following formula (d5-1), etc.

[0162] Examples of the compound containing a group having a polymerizable carbon-carbon bond include a compound having a (meth)acryloyl group, a maleimide group, an alkenyl group, a vinylphenyl group, a vinyl ether group or a 3-methylenetetrahydrofuran-2(3H)-one-5-yl group. Specific examples thereof include ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, compounds represented by the following formula (d6-1) to formula (d6-8), respectively.

[0163] [Chemical formula 10]

[0164]

[0165] [Chemical formula 11]

[0166]

[0167] (In formula (d2-5), Ac is an acetyl group)

[0168] [Chemical formula 12]

[0169]

[0170] [Chemical formula 13]

[0171]

[0172] [Chemical formula 14]

[0173]

[0174] [Chemical formula 15]

[0175]

[0176] In terms of the aspect of being able to well balance and exhibit the improvement effects of the liquid crystal alignment property and low-voltage drivability in the liquid crystal element and the improvement effect of the adhesion to the liquid crystal alignment film, the crosslinking agent is preferably a compound among the above that has two or more crosslinkable groups selected from the group consisting of oxiranyl, protected oxiranyl, oxetanyl, hydroxyalkylamide group, protected hydroxyalkylamide group, amino group, protected amino group, and protected isocyanate group in one molecule, and more preferably a compound that has two or more crosslinkable groups selected from the group consisting of oxiranyl, protected oxiranyl, oxetanyl, hydroxyalkylamide group, and protected hydroxyalkylamide group in one molecule.

[0177] As the crosslinking agent, in terms of being able to fully achieve the low-voltage drivability of the liquid crystal element and at the same time obtain a liquid crystal element with more excellent liquid crystal alignment property, a compound without an aromatic ring (hereinafter, also referred to as "aliphatic crosslinking agent") can be preferably used. The aliphatic crosslinking agent can be a compound containing a chain structure or can have a cyclic structure. As a specific example of the aliphatic crosslinking agent, a compound without an aromatic ring among the exemplified compounds can be cited.

[0178] From the viewpoint of obtaining a liquid crystal alignment film showing weak anchoring characteristics and at the same time improving the mechanical properties and adhesion of the liquid crystal alignment film, with respect to 100 parts by mass of the total amount of the polymer components contained in the liquid crystal aligning agent (that is, the total amount of the polymer (P) and other polymers), the content of the crosslinking agent is preferably 0.5 part by mass or more. With respect to 100 parts by mass of the total amount of the polymer components, the content of the crosslinking agent is more preferably 1 part by mass or more, and further preferably 2 parts by mass or more. In addition, from the viewpoint of obtaining a liquid crystal element showing good liquid crystal alignment property, with respect to 100 parts by mass of the total amount of the polymer components, the content of the crosslinking 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.

[0179] <Other components>

[0180] In addition to the polymer (P) and the crosslinking agent, the liquid crystal aligning agent of the present disclosure may optionally contain components different from the polymer (P) and the crosslinking agent (hereinafter, also referred to as "other components"). Examples of other components include polymers different from the polymer (P) (hereinafter, also referred to as "other polymers"), adhesion aids, solvents, and the like.

[0181] (Other polymer)

[0182] The other polymer may be a polymer that does not have an aliphatic ring with 7 or more ring members, and the type of its main skeleton is not particularly limited. Examples of other polymers include: polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamideimide, addition polymer, polybenzoxazole, etc. Examples of addition polymers include: (meth)acrylic polymers, styrene polymers, maleimide polymers, (meth)acrylic-styrene copolymers, (meth)acrylic-maleimide copolymers, (meth)acrylic-styrene-maleimide copolymers, and styrene-maleimide copolymers, etc.

[0183] From the viewpoint of obtaining a liquid crystal element with excellent liquid crystal alignment properties and reliability, the other polymer is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, and addition polymer, and more preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. In terms of forming a liquid crystal alignment film with more excellent adhesion, the other polymer is particularly preferably at least one selected from the group consisting of polyamic acid and polyimide.

[0184] When the liquid crystal aligning agent contains an other polymer, the content of the other polymer is preferably 99 parts by mass or less, more preferably 90 parts by mass or less, and still more preferably 85 parts by mass or less, based on 100 parts by mass of the polymer components contained in the liquid crystal aligning agent (i.e., the total amount of the polymer (P) and the other polymer).

[0185] (Adhesion aid)

[0186] The adhesion aid is a component that improves the adhesion between the liquid crystal alignment film formed using the liquid crystal aligning agent and the substrate or the sealant. As the adhesion aid, a functional silane coupling agent having a reactive functional group can be preferably used. Examples of the reactive functional groups possessed by the functional silane coupling agent include: carboxyl group, (meth)acryloyl group, oxiranyl group, oxetanyl group, vinyl group, isocyanate group, etc.

[0187] As specific examples of the functional silane coupling agent, for example, trimethoxysilylbenzoic acid, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, etc. can be cited.

[0188] When the liquid crystal aligning agent of the present disclosure contains an adhesion promoter, the content of the adhesion promoter is preferably 0.1 part by mass to 20 parts by mass, more preferably 0.2 part by mass to 10 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0189] (Solvent)

[0190] The liquid crystal aligning agent of the present disclosure is prepared in the form of a liquid composition in which a polymer (P), a crosslinking agent, and, if necessary, components are preferably dispersed or dissolved in a suitable solvent.

[0191] As the solvent, an organic solvent can be preferably used. As specific examples thereof, amides such as N,N-dimethylformamide and N,N-dimethylacetamide; lactams such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and γ-butyrolactam; ureas such as 1,2-dimethyl-2-imidazolidinone and 1,3-dimethyl-2-imidazolidinone; lactones such as γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate;

[0192] ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monon-propyl ether, ethylene glycol monon-butyl ether (butyl cellosolve), diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monon-propyl ether, diethylene glycol monon-butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monon-propyl ether, propylene glycol monon-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monon-propyl ether, dipropylene glycol monon-butyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, etc. (poly)alkylene glycol monoalkyl ethers;

[0193] Alkyl lactates such as methyl lactate, ethyl lactate, butyl lactate; alkyl alcohols which may have a straight-chain, branched or cyclic structure such as methanol, ethanol, propanol, butanol, isopropanol, isobutanol, tert-butanol, octanol, 2-ethylhexanol, cyclohexanol; alkoxy alcohols such as 3-methoxy-1-butanol; keto alcohols such as diacetone alcohol; (poly)alkylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate; ethers such as diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, tetrahydrofuran; ketones such as methyl ethyl ketone, diisobutyl ketone, cyclohexanone, cyclopentanone, 2-heptanone, 3-heptanone;

[0194] Diacetates such as propylene glycol diacetate, 1,3-butanediol diacetate, 1,6-hexanediol diacetate; alkoxycarboxylic acid esters such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxyacetate, 3-methyl-3-methoxybutyl propionate; other esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl formate, isoamyl acetate, n-butyl propionate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-butyl butyrate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl 2-oxobutyrate; aromatic hydrocarbons such as toluene, xylene; phenols such as phenol, methylphenol, etc.

[0195] As other components contained in the liquid crystal aligning agent, in addition to those described above, for example, surfactants, antioxidants, metal chelating compounds, curing accelerators, fillers, dispersants, photosensitizers, etc. can be cited. The blending ratio of other components can be appropriately selected according to each compound within the range not impairing the effects of the present disclosure.

[0196] The solid content concentration in the liquid crystal aligning agent (the proportion of the total mass of components other than the solvent of the liquid crystal aligning agent in the total mass of the liquid crystal aligning agent) can be appropriately selected in consideration of viscosity, volatility, etc. The solid content concentration of the liquid crystal aligning agent is preferably in the range of 1% by mass to 10% by mass. If the solid content concentration is 1% by mass or more, the film thickness of the coating film can be sufficiently ensured, and a liquid crystal alignment film showing better liquid crystal alignment properties can be obtained, which is preferable in this regard. In addition, if the solid content concentration is 10% by mass or less, the coating film can be set to an appropriate thickness, and it is easy to obtain a liquid crystal alignment film showing good liquid crystal alignment properties. Furthermore, the viscosity of the liquid crystal aligning agent becomes appropriate, and good coatability can be ensured.

[0197] Weak Anchoring Liquid Crystal Alignment Film and Method for Producing the Same

[0198] The liquid crystal alignment film of the present disclosure is a weak anchoring film manufactured using the liquid crystal aligning agent prepared as described above. Here, the so-called "weak anchoring" means that the alignment restraining force of liquid crystal molecules is substantially zero in the in-plane direction, and even if the horizontal alignment of liquid crystal molecules is forced, the alignment restraining force in the in-plane direction is also substantially zero. In the state of weak anchoring (also known as zero surface anchoring), the in-plane alignment direction can be freely rotated by 360° by controlling external fields such as an electric field and a magnetic field.

[0199] The method for manufacturing a weak anchoring liquid crystal alignment film using the liquid crystal aligning agent of the present disclosure is not particularly limited, and the same method as that for manufacturing a liquid crystal alignment film using a conventionally known liquid crystal aligning agent can be used. In terms of simplicity of film formation, a method of forming by coating the liquid crystal aligning agent of the present disclosure on a substrate and preferably heating the coated surface is preferred.

[0200] The substrate for forming the liquid crystal alignment film is not particularly limited. As the substrate, for example, the following transparent substrates can be used: glass such as float glass and soda glass; plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefin).

[0201] The method for coating the liquid crystal aligning agent on the substrate is not particularly limited. The coating of the liquid crystal aligning agent can be carried out, for example, by spin coating, printing methods (for example, offset printing method, flexographic printing method, etc.), inkjet method, slit coating method, bar coater method, extrusion die method, direct gravure coater method, chamber doctor coater method, offset gravure coater method, impregnation coater method, MB coater method, etc.

[0202] After coating the liquid crystal aligning agent, preheating (pre-baking) is preferably carried out for the purpose of preventing sagging of the liquid crystal aligning agent. The pre-baking temperature is preferably 30°C to 200°C, and the pre-baking time is preferably 0.25 minutes to 10 minutes. Thereafter, a calcination (post-baking) process is carried out for the purpose of further removing the solvent. The calcination temperature (post-baking temperature) is preferably 80°C to 280°C, more preferably 80°C to 250°C. The post-baking time is preferably 5 minutes to 200 minutes. The film thickness of the formed film is preferably 0.001 μm to 2.5 μm. By the above operations, a weak anchoring liquid crystal alignment film can be simply manufactured. In addition, if necessary, an alignment treatment (for example, rubbing alignment treatment or photo-alignment treatment) can be carried out on the coated film after post-baking to obtain a weak anchoring liquid crystal alignment film.

[0203] "Liquid Crystal Element and Method for Manufacturing the Same"

[0204] The liquid crystal element of the present disclosure includes a weak-anchoring liquid crystal alignment film formed using the liquid crystal aligning agent described in the above. The driving method of the liquid crystal in the liquid crystal element is not particularly limited. For example, it can be applied to various modes such as Twisted Nematic (TN) type, Super Twisted Nematic (STN) type, Vertical Alignment (VA) type (including Vertical Alignment-Multi-domain Vertical Alignment (VA-MVA) type, Vertical Alignment-Patterned Vertical Alignment (VA-PVA) type, etc.), In-Plane Switching (IPS) type, Fringe Field Switching (FFS) type, Optically Compensated Bend (OCB) type, Polymer Sustained Alignment (PSA) type, Electrically Controlled Birefringence (ECB) type, etc. Among these, it can be preferably applied to liquid crystal elements of horizontal modes such as IPS type or FFS type. The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. The substrate used in step 1 varies depending on the desired operation mode. Steps 2 and 3 are common to each operation mode.

[0205] <Step 1: Formation of Coating Film>

[0206] First, by coating a liquid crystal aligning agent on each substrate surface of a pair of substrates, preferably heating the coating surface to form a coating film on the substrate. The liquid crystal element of the present disclosure is preferably manufactured by a method including the following steps: a step of coating a liquid crystal aligning agent for forming a strong-anchoring liquid crystal alignment film on one of the pair of substrates; and a step of coating the liquid crystal aligning agent of the present disclosure (i.e., the liquid crystal aligning agent for forming a weak-anchoring film) on the other substrate. As the liquid crystal aligning agent for forming a strong-anchoring liquid crystal alignment film, a conventionally known liquid crystal aligning agent can be suitably used.

[0207] Regarding the pair of substrates, for example, in the case of manufacturing a liquid crystal element of IPS type or FFS type, a substrate provided with electrodes patterned in a comb shape (hereinafter, also referred to as "first substrate") and an opposing substrate without electrodes (hereinafter, also referred to as "second substrate") are used. As the electrodes, a transparent conductive film can be cited. As the transparent conductive film, one containing tin oxide (SnO 2) NESA film (registered trademark of PPG Industries, Inc. in the United States), indium tin oxide (ITO) film containing indium oxide - tin oxide (In 2 O 3 -SnO 2 ), etc. As aspects of forming a liquid crystal alignment film on the first substrate and the second substrate, the following can be cited: an aspect of forming a strongly anchoring liquid crystal alignment film on the first substrate and a weakly anchoring liquid crystal alignment film on the second substrate (first aspect); an aspect of forming a weakly anchoring liquid crystal alignment film on the first substrate and a strongly anchoring liquid crystal alignment film on the second substrate (second aspect). Among these, from the viewpoint of low - voltage driving of the liquid crystal element, the first aspect is preferred.

[0208] <Process 2: Alignment treatment>

[0209] In the case of manufacturing an IPS - type or FFS - type liquid crystal element, for at least one of the coating films formed on the first substrate and the second substrate in the above - mentioned process 1, a treatment for imparting liquid crystal alignment ability (alignment treatment) is performed. As the alignment treatment, a rubbing treatment using cotton or nylon, etc. to wipe the surface of the coating film formed on the substrate, or a photo - alignment treatment for irradiating the coating film to impart liquid crystal alignment ability can be preferably used. The alignment treatment can be performed on the coating film formed on the first substrate and the coating film formed on the second substrate respectively, or can be performed only on one of the coating film formed on the first substrate and the coating film formed on the second substrate. From the viewpoint of obtaining a liquid crystal element showing good liquid crystal alignment, it is preferred to coat a liquid crystal aligning agent for forming a strongly anchoring liquid crystal alignment film on one of the first substrate and the second substrate, and perform the alignment treatment only on the coating film thus formed. In the above - mentioned case, the strongly anchoring liquid crystal alignment film can be a rubbed alignment film formed by a rubbing alignment treatment or a photo - alignment film formed by a photo - alignment treatment. In terms of making the liquid crystal alignment and adhesion more excellent, the liquid crystal aligning agent for forming a strongly anchoring liquid crystal alignment film preferably contains a cross - linker. In terms of a high improvement effect on low - voltage driving of the liquid crystal element, it is more preferred that the cross - linker does not have an aromatic ring.

[0210] In addition, according to the weakly anchoring liquid crystal alignment film formed from the liquid crystal aligning agent of the present disclosure, a liquid crystal element showing good liquid crystal alignment can be obtained even without alignment treatments such as a rubbing alignment treatment or a photo - alignment treatment. This property can also be utilized to configure the weakly anchoring liquid crystal alignment film formed from the liquid crystal aligning agent of the present disclosure as a protective film provided on a color filter in the liquid crystal element, so that the weakly anchoring liquid crystal alignment film has the function of a protective film (specifically, planarization or protection from impurities, humidity, etc.).

[0211] <Process 3: Construction of liquid crystal cell>

[0212] Prepare two substrates formed with a liquid crystal alignment film as described above to manufacture a liquid crystal cell in which a liquid crystal layer is disposed between two substrates arranged to face each other. When manufacturing the liquid crystal cell, for example, the following methods can be cited: a method of arranging two substrates to face each other with a gap therebetween in such a manner that the liquid crystal alignment films face each other, bonding the peripheral portions of the two substrates with a sealant, injecting and filling liquid crystal into the cell gap surrounded by the substrate surfaces and the sealant, and sealing the injection holes; a method using the One Drop Fill (ODF) method. As the sealant, for example, an epoxy resin containing a hardening agent and alumina balls as spacers can be used. As the liquid crystal constituting the liquid crystal layer, nematic liquid crystal and smectic liquid crystal can be cited, and among them, nematic liquid crystal is preferred.

[0213] When manufacturing a liquid crystal display device, a polarizing plate is then bonded to the outer surface of the liquid crystal cell. As the polarizing plate, for example, a polarizing plate formed by sandwiching a polarizing film called an "H film" obtained by stretching and orienting polyvinyl alcohol and absorbing iodine therewith with a cellulose acetate protective film, or a polarizing plate including the H film itself can be cited.

[0214] The liquid crystal element of the present disclosure can be effectively applied to various uses. Specifically, for example, it can be used as various display devices such as a clock, a portable game machine, a word processor, a notebook personal computer, a car navigation system, a camcorder, a personal digital assistant (PDA), a digital camera, a mobile phone, a smartphone, various monitors, a liquid crystal television, an information display, or a dimming device, a retardation film, etc.

[0215] According to the present disclosure described in detail above, the following means are provided.

[0216] 〔Means 1〕A liquid crystal aligning agent for forming a weak anchoring film, which is used to form a weak anchoring liquid crystal alignment film, and the liquid crystal aligning agent for forming a weak anchoring film contains: a polymer (P) having an aliphatic ring with 7 or more ring members in the side chain; and a crosslinking agent.

[0217] 〔Means 2〕The liquid crystal aligning agent for forming a weak anchoring film according to 〔Means 1〕, wherein the crosslinking agent does not have an aromatic ring.

[0218] 〔Means 3〕The liquid crystal aligning agent for forming a weak anchoring film according to 〔Means 1〕 or 〔Means 2〕, wherein the polymer (P) is at least one selected from the group consisting of an addition polymer, polyamic acid, polyamic acid ester, polyimide, and polyorganosiloxane.

[0219] [Means 4] The liquid crystal aligning agent for forming a weak anchoring film according to any one of [Means 1] to [Means 3], wherein the polymer (P) has an aliphatic ring with 8 or more ring members in the side chain.

[0220] [Means 5] The liquid crystal aligning agent for forming a weak anchoring film according to any one of [Means 1] to [Means 4], further containing a polymer (Q), wherein the polymer (Q) does not have an aliphatic ring with 7 or more ring members in the side chain.

[0221] [Means 6] The liquid crystal aligning agent for forming a weak anchoring film according to [Means 5], wherein the polymer (Q) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

[0222] [Means 7] A method for manufacturing a liquid crystal alignment film, using the liquid crystal aligning agent according to any one of [Means 1] to [Means 6] to form a weak anchoring liquid crystal alignment film.

[0223] [Means 8] A method for manufacturing a liquid crystal element, wherein the liquid crystal element includes 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 the liquid crystal element includes the following steps: coating the surface of at least one of the first substrate and the second substrate with the liquid crystal aligning agent for forming a weak anchoring film according to any one of [Means 1] to [Means 6] to form a weak anchoring liquid crystal alignment film.

[0224] [Means 9] The method for manufacturing a liquid crystal element according to [Means 8], wherein the weak anchoring liquid crystal alignment film is formed on the surface of one of the first substrate and the second substrate. The method for manufacturing the liquid crystal element further includes the following steps: forming a strong anchoring liquid crystal alignment film having a stronger anchoring energy than the weak anchoring liquid crystal alignment film on the surface of the substrate different from the substrate on which the weak anchoring liquid crystal alignment film is formed among the first substrate and the second substrate.

[0225] [Means 10] The method for manufacturing a liquid crystal element according to [Means 9], wherein the strong anchoring liquid crystal alignment film is a rubbed alignment film or a photo-alignment film.

[0226] [Means 11] The method for manufacturing a liquid crystal element according to [Means 9] or [Means 10], wherein the first substrate has a pair of electrodes, the second substrate does not have electrodes, the strong anchoring liquid crystal alignment film is formed on the surface of the first substrate, and the weak anchoring liquid crystal alignment film is formed on the surface of the second substrate.

[0227] [Examples]

[0228] Hereinafter, specific descriptions will be given through examples, but the present invention is not limited to the following examples.

[0229] In the following examples, the imidization rate of the polyimide and the molecular weights (Mw, Mn) of the polymer are measured using the following methods.

[0230] <Imidization Rate of Polyimide>

[0231] The polyimide solution is poured into pure water, and the obtained precipitate is thoroughly dried under reduced pressure at room temperature and then dissolved in deuterated dimethyl sulfoxide. Using tetramethylsilane as the reference substance, proton nuclear magnetic resonance ( 1 H-Nuclear Magnetic Resonance, 1 H-NMR) measurement is performed at room temperature. Based on the obtained 1 H-NMR spectrum, the imidization rate [%] is calculated using the following formula (1).

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

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

[0234] <Molecular Weights (Mw, Mn) of Polymer>

[0235] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) are measured by gel permeation chromatography (GPC) under the following conditions.

[0236] Apparatus: "GPC-101" manufactured by Showa Denko K.K.

[0237] GPC column: Connect "GPC-KF-801", "GPC-KF-802", "GPC-KF-803", and "GPC-KF-804" manufactured by Shimadzu GLC K.K.

[0238] Mobile phase: Tetrahydrofuran (THF)

[0239] Column temperature: 40 °C

[0240] Flow rate: 1.0 mL / min

[0241] Sample concentration: 1.0 mass%

[0242] Sample injection volume: 100 μL

[0243] Detector: differential refractometer

[0244] Standard substance: monodisperse polystyrene

[0245] The following shows the abbreviations of the compounds used in the following examples. In addition, for the sake of convenience of explanation, the "compound represented by formula (X)" is sometimes simply represented as "compound (X)". In the examples and comparative examples, "parts" and "%" are based on mass unless otherwise specified.

[0246] (Monomer with unsaturated bond) MA-1 to MA-9

[0247] [Chemical formula 16]

[0248]

[0249] (Monomer with unsaturated bond) MB-1 to MB-12

[0250] [Chemical formula 17]

[0251]

[0252] (Tetracarboxylic dianhydride) T-1 to T-9

[0253] [Chemical formula 18]

[0254]

[0255] (Diamine) DA-1 to DA-4, daa-1, daa-2

[0256] [Chemical formula 19]

[0257]

[0258] (Diamine) DB-1 to DB-18

[0259] [Chemical formula 20]

[0260]

[0261] (Additive) AD-1 to AD-7

[0262] [Chemical formula 21]

[0263]

[0264] <Synthesis of polymer>

[0265] 1. Synthesis of styrene-maleimide copolymer

[0266] [Synthesis Example 1]

[0267] Under nitrogen, 35 mol parts of compound (MB-4), 45 mol parts of compound (MB-1), and 20 mol parts of compound (MB-1), totaling 100 mol parts relative to the total amount of the polymerization monomers, 0.3922 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator (10 mass parts relative to 100 mass parts of the total amount of the polymerization monomers), and 15.68 g of N-methyl-2-pyrrolidone (NMP) as a solvent (400 mass parts relative to 100 mass parts of the total amount of the polymerization monomers) were added to a 100 mL two-necked flask, and polymerization was carried out at 70 °C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and vacuum dried at room temperature for 8 hours to obtain the target addition polymer (designated as polymer (PM-1)).

[0268] [Synthesis Examples 2 to 10]

[0269] The types and amounts of the polymerization monomers used were changed as described in Table 1, and otherwise the same operations as in Synthesis Example 1 were carried out to obtain addition polymers (designated as polymers (PM-2) to (PM-10)).

[0270] [Table 1]

[0271]

[0272] 2. Synthesis of polyamic acid

[0273] [Synthesis Example 11]

[0274] 50 mol parts of compound (T-1) and 50 mol parts of compound (T-2) as tetracarboxylic dianhydrides, 60 mol parts of compound (DB-6), 20 mol parts of compound (DB-5), and 20 mol parts of compound (DB-8) as diamine compounds were dissolved in N-methyl-2-pyrrolidone (NMP), and the reaction was carried out at 60 °C for 6 hours to obtain a solution containing 20 mass% of polyamic acid (designated as polymer (PAA-1)).

[0275] [Synthesis Examples 12 to 16, Synthesis Examples 18 to 21, Synthesis Example 23]

[0276] The types and amounts of the tetracarboxylic dianhydrides and diamine compounds used were changed as described in Table 2, and otherwise the same operations as in Synthesis Example 11 were carried out to obtain polyamic acids (Polymer (PAA-2) to Polymer (PAA-6), Polymer (PAA-8) to Polymer (PAA-11), Polymer (PAA-13)). In addition, the numerical values of the tetracarboxylic dianhydrides (Acid dianhydride 1 to Acid dianhydride 3) in Table 2 represent the ratios (molar ratios) of the respective compounds to 100 mol parts of the total amount of the tetracarboxylic dianhydrides used in the synthesis of the polymer. The numerical values of the diamine compounds (Diamine 1 to Diamine 4) represent the ratios (molar ratios) of the respective compounds to 100 mol parts of the total amount of the diamine compounds used in the synthesis of the polymer.

[0277] 3. Synthesis of Polyimide

[0278] [Synthesis Example 17]

[0279] 50 mol parts of compound (T-1) and 50 mol parts of compound (T-2) as tetracarboxylic dianhydrides, and 60 mol parts of compound (DA-4), 20 mol parts of compound (DB-5) and 20 mol parts of compound (DB-8) as diamine compounds were dissolved in NMP, and reacted at 60 °C for 6 hours to obtain a solution containing 20% by mass of polyamic acid. Subsequently, NMP was added to the obtained polyamic acid solution to prepare a solution having a polyamic acid concentration of 10% by mass, pyridine and acetic anhydride were added, and a dehydration ring-closing reaction was carried out at 80 °C for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by mass of polyimide (designated as Polymer (PAA-7)) with an imidization rate of about 50%.

[0280] [Synthesis Examples 22 and 24]

[0281] The types and amounts of the tetracarboxylic dianhydrides and diamine compounds used were changed as described in Table 2, and otherwise the same operations as in Synthesis Example 17 were carried out to obtain polyimides (Polymer (PAA-12), Polymer (PAA-14)).

[0282] [Table 2]

[0283]

[0284] <Preparation and Evaluation of Liquid Crystal Alignment Agent>

[0285] [Example 1: Friction-Aligned FFS-Type Liquid Crystal Display Element]

[0286] 1. Preparation of Liquid Crystal Alignment Agent

[0287] (1) Preparation of Liquid Crystal Alignment Agent for Weak Anchoring Film Formation

[0288] To 100 parts by mass of the polymer (PM-2) obtained in Synthesis Example 2, 7 parts by mass of Compound (AD-2) and 2 parts by mass of Compound (AD-5) were added. Further, it was diluted with N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), butyl cellosolve (BC), diacetone alcohol (DAA), and diethylene glycol diethyl ether (DEDG) to prepare a solution having a solvent composition ratio of NMP:GBL:BC:DAA:DEDG = 30:30:15:15:10 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-1).

[0289] (2) Preparation of a liquid crystal aligning agent for forming a strong anchoring film by the rubbing alignment method

[0290] A solution containing 70 parts by mass of the polymer (PAA-11) obtained in Synthesis Example 21 was mixed with a solution containing 30 parts by mass of the polymer (PAA-13) obtained in Synthesis Example 23. 3 parts by mass of Compound (AD-1) was added to the mixture, and it was further diluted with NMP, GBL, BC, DAA, and DEDG to prepare a solution having a solvent composition ratio of NMP:GBL:BC:DAA:DEDG = 30:30:15:15:10 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-R1).

[0291] (3) Fabrication and evaluation of a liquid crystal display device

[0292] Fabrication Figure 1 The FFS type liquid crystal display device 10 shown in the figure was fabricated and various characteristics were evaluated. When fabricating the FFS type liquid crystal display device 10, first, a substrate having an electrode pair in which a bottom electrode 15 without a pattern, an insulating layer 14 of a silicon nitride film, and a top electrode 13 patterned into a comb shape were sequentially formed on one side of a glass substrate 11a (referred to as the first substrate) and an opposing glass substrate 11b without an electrode (referred to as the second substrate) were prepared.

[0293] A plan view of the top electrode 13 used is shown in Figure 2 (a) of Figure 2 (b) of Figure 2 (a) of which is a top view of the top electrode 13, Figure 2 (b) of which is Figure 2An enlarged view of the portion C1 surrounded by the dashed line in (a). In this embodiment, the line width d1 of the electrode is set to 4 μm, and the distance d2 between the electrodes is set to 6 μm. In addition, as the top electrode 13, four systems of driving electrodes, namely electrode A, electrode B, electrode C, and electrode D, are used ( Figure 3 ). In addition, the bottom electrode 15 functions as a common electrode that acts on all four systems of driving electrodes, and the regions of the four systems of driving electrodes respectively become pixel regions. In addition, Figure 1 in the figure, the symbol 12 represents the liquid crystal alignment film, and the symbol 16 represents the liquid crystal layer.

[0294] (i) Formation of a weakly anchored liquid crystal alignment film

[0295] The weakly anchored liquid crystal aligning agent (AL-1) prepared in the above (1) is coated on one substrate surface of the second substrate using a spin coater, heated on a hot plate at 80 °C for 1 minute, and then heated in an oven at 230 °C with nitrogen replacement in the chamber for 30 minutes to form a weakly anchored liquid crystal alignment film with an average film thickness of 100 nm.

[0296] (ii) Formation of a strongly anchored liquid crystal alignment film by the rubbing alignment method

[0297] The strongly anchored liquid crystal aligning agent (AL-R1) prepared in the above (2) is coated on the electrode formation surface of the first substrate using a spin coater, heated on a hot plate at 80 °C for 1 minute, and then heated in an oven at 230 °C with nitrogen replacement in the chamber for 30 minutes to form a coating film with an average film thickness of 100 nm. For the surface of the coating film, a rubbing machine with a roller wound with a rayon cloth is used, and two rubbing treatments are performed at a roller rotation speed of 1,000 rpm, a stage moving speed of 30 mm / second, and a hair pressing length of 0.3 mm. At this time, the rubbing direction is set parallel to the direction of the double-headed arrow in Figure 2 the (b). The coating film subjected to the rubbing alignment treatment is ultrasonically cleaned in ultrapure water for 1 minute, and then dried in an oven at 100 °C for 10 minutes to form a strongly anchored liquid crystal alignment film.

[0298] (iii) Fabrication of the FFS type liquid crystal display element

[0299] For the outer periphery of the surface with the liquid crystal alignment film in the substrates fabricated in the above (i) and (ii), a liquid crystal injection port is left, and an epoxy resin adhesive containing alumina spheres with a diameter of 3.5 μm is coated using a dispenser. Subsequently, the surfaces with the liquid crystal alignment films of a pair of substrates are faced and pressed together, and the adhesive is thermally cured at 150 °C for 1 hour. Then, a negative 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, and the liquid crystal injection port is sealed using an epoxy-based adhesive. Further, in order to remove the flow alignment during liquid crystal injection, it is heated at 120 °C and then slowly cooled to room temperature.

[0300] (iv) Evaluation of adhesion

[0301] The weak anchoring liquid crystal aligning agent (AL-1) prepared in the above (1) and the strong anchoring liquid crystal aligning agent (AL-R1) prepared in the above (2) are respectively coated on glass substrates using a spin coater. After heating on a hot plate at 80 °C for 1 minute, they are heated in an oven at 230 °C with nitrogen replacement in the chamber for 30 minutes, thereby fabricating two glass substrates with coatings having an average film thickness of 100 nm. Next, a liquid crystal sealant (manufactured by Sekisui Chemical Co., Ltd., S-WB21) is coated on the central portion of the surface with the coating of one glass substrate, and the other glass substrate is bonded in such a way that the coating contacts the liquid crystal sealant. The coating amount of the liquid crystal sealant is set so that the diameter of the liquid crystal sealant after substrate bonding becomes 4 mm. Then, after irradiating with light of 30,000 J / m 2 (converted to 365 nm) using a metal halide lamp, it is heated in an oven at 120 °C for 1 hour, thereby obtaining an evaluation cell. Then, the evaluation cell is pressed using a small tabletop testing machine (model: EZ-LX) manufactured by Shimadzu Corporation, and the pressure (N) at which the film peels off (mainly peeling caused by interfacial failure between the liquid crystal sealant and the film or cohesive failure inside the liquid crystal sealant) is measured. By dividing the pressure (N) at the time of peeling by the area of the liquid crystal sealant (mm 2 ), the adhesion between the film and the liquid crystal sealant and the substrate is calculated (N / mm 2 ). Regarding the evaluation, the case where the measured value of the pressure is 1.5 N / mm 2 or more is set as "good (◎)", the case where it is 1.0 N / mm 2 or more and less than 1.5 N / mm 2 is set as "acceptable (○)", and the case where it is less than 1.0 N / mm 2 is set as "poor (×)". As a result, the evaluation in this example is "acceptable (○)".

[0302] (v) Evaluation of low voltage driving

[0303] The liquid crystal display element manufactured in (iii) is sandwiched by two polarizing plates in the manner of minimum brightness, and the liquid crystal display element is disposed between a backlight and a luminance meter which are arranged with their optical axes aligned. Then, a voltage is applied to the liquid crystal display element at intervals of 0.1 V up to 10 V. By measuring the luminance with respect to the applied voltage, a V-T curve is obtained, and the value of the voltage at which the luminance becomes maximum is estimated. Regarding the evaluation, for the second substrate as well as for the first substrate, a liquid crystal display element after using the strong anchoring liquid crystal aligning agent (AL-R1) prepared in (2) and forming a liquid crystal alignment film by the rubbing alignment method is prepared as a reference cell, and it is judged based on to what extent the maximum luminance voltage of the liquid crystal display element manufactured in each example is reduced in voltage with respect to the maximum luminance voltage of the reference cell. Those in which the maximum luminance voltage of the liquid crystal display element manufactured in (iii) is reduced in voltage by 0.8 V or more with respect to the maximum luminance voltage of the reference cell are rated as "good (◎)", those in which the voltage is reduced by 0.4 V or more and less than 0.8 V with respect to the maximum luminance voltage of the reference cell are rated as "acceptable (○)", and those in which the voltage reduction of the maximum luminance voltage of the liquid crystal display element with respect to the reference cell is less than 0.4 V are rated as "poor (×)". As a result, in this example, the rating is "acceptable (○)".

[0304] (vi) Evaluation of liquid crystal alignment property (AC afterimage property)

[0305] For the liquid crystal display element manufactured in (iii), an alternating current voltage that gives maximum luminance is applied using a birefringence meter (manufactured by AXOMETRICS, AXOSTEP high-precision Mueller Matrix Imaging Polarimeter), and the change in the liquid crystal azimuth angle before and after driving for 2 days is measured. Regarding the evaluation, a change in the liquid crystal azimuth angle of less than 0.5 degrees is rated as "good (◎)", a change of 0.5 degrees or more and less than 1 degree is rated as "acceptable (○)", and a change of 1 degree or more is rated as "poor (△)". The smaller the change in the liquid crystal azimuth angle, the less likely it is to generate an AC afterimage even when the liquid crystal display element is driven for a long time, and it can be said that the liquid crystal alignment property is better. As a result, in this example, the rating is "good (◎)".

[0306] [Example 2, Example 3, Example 7 to Example 10, Example 12, Example 13, Comparative Example 1 to Comparative Example 7]

[0307] The polymers and additives contained in the weak-anchoring liquid crystal aligning agent were changed as shown in Table 3 below. Except for this, a liquid crystal aligning agent was prepared in the same manner as in Example 1 to form a liquid crystal alignment film, and a rubbed-alignment FFS-type liquid crystal display element was manufactured and various evaluations were carried out. The evaluation results are shown in Table 3 below.

[0308] [Example 4]

[0309] The polymers and additives contained in the weak-anchoring liquid crystal aligning agent were changed as shown in Table 3 below, and the liquid crystal alignment film formed using the weak-anchoring liquid crystal aligning agent was also subjected to a rubbing alignment treatment. Except for the above aspects, a liquid crystal aligning agent was prepared in the same manner as in Example 1 to form a liquid crystal alignment film, and a rubbed-alignment FFS-type liquid crystal display element was manufactured and various evaluations were carried out. In addition, the conditions for the rubbing alignment treatment of the liquid crystal alignment film formed using the weak-anchoring liquid crystal aligning agent were set to the same conditions as those for the rubbing alignment treatment of the liquid crystal alignment film formed using the strong-anchoring liquid crystal aligning agent. The evaluation results are shown in Table 3 below. In Table 3, the numerical values in the polymer column and the additive column represent the blending ratio (parts by mass) of each compound in terms of solid content relative to 100 parts by mass of the total amount of the polymer components used in the preparation of the liquid crystal aligning agent.

[0310] [Example 5: Photoalignment FFS-Type Liquid Crystal Display Element]

[0311] (1) Preparation of Weak-Anchoring Liquid Crystal Aligning Agent

[0312] A solution containing 20 parts by mass of the polymer (PM-6) obtained in Synthesis Example 6 was mixed with a solution containing 80 parts by mass of the polymer (PAA-8). 5 parts by mass of the compound (AD-2) was added to the mixture, and further diluted with NMP, N-ethyl-2-pyrrolidone (NEP), GBL, and BC to obtain a solution having a solid content concentration of 4.0% by mass and a solvent composition ratio of NMP:NEP:GBL:BC = 25:25:25:25 (mass ratio). The solution was filtered through a filter with a pore size of 0.2 μm to prepare a weak-anchoring liquid crystal aligning agent (AL-5).

[0313] (2) Preparation of Liquid Crystal Aligning Agent for Strong-Anchoring Film Formation by Photoalignment Method

[0314] A solution containing 70 parts by mass of the polymer (PAA-11) obtained in Synthesis Example 21 was mixed with a solution containing 30 parts by mass of the polymer (PAA-14) obtained in Synthesis Example 24. 3 parts by mass of compound (AD-2) was added to the mixture, and then diluted with NMP, NEP, GBL, and BC to prepare a solution having a solvent composition ratio of NMP:NEP:GBL:BC = 25:25:25:25 (mass ratio) and a solid content concentration of 3.5 mass%. The solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-P1).

[0315] (3) Fabrication and evaluation of liquid crystal display elements

[0316] Fabrication Figure 1 The FFS-type liquid crystal display element 10 shown in the figure was fabricated and various characteristics were evaluated.

[0317] (i) Formation of a strongly anchored liquid crystal alignment film by photoalignment method

[0318] The strongly anchored liquid crystal aligning agent (AL-P1) prepared in (2) above was coated on the electrode formation surface of the first substrate using a spin coater. Subsequently, it was heated on a hot plate at 80 °C for 1 minute, and then heated in an oven at 230 °C with the inside of the chamber purged with nitrogen for 30 minutes to form a coating film with an average film thickness of 100 nm. For the surface of the coating film, ultraviolet light containing a bright line of 254 nm linearly polarized light was irradiated from the substrate normal direction using a Hg-Xe lamp at 200 mJ / cm 2 for photoalignment treatment. At this time, the direction of the polarization plane of the polarized ultraviolet light projected onto the line segment on the substrate was set to be orthogonal to the direction of the double-headed arrow in Figure 2 (b). The coating film subjected to photoalignment treatment was heated in an oven at 230 °C with the inside of the chamber purged with nitrogen for 30 minutes for heat treatment to form a strongly anchored liquid crystal alignment film.

[0319] (ii) Formation of a weakly anchored liquid crystal alignment film

[0320] The weakly anchored liquid crystal aligning agent (AL-5) prepared in (1) above was coated on one surface of the second substrate using a spin coater. After heating on a hot plate at 80 °C for 1 minute, it was heated in an oven at 230 °C with the inside of the chamber purged with nitrogen for 30 minutes to form a weakly anchored liquid crystal alignment film with an average film thickness of 100 nm.

[0321] (iii) Fabrication of FFS-type liquid crystal display element

[0322] Using the pair of substrates fabricated in (i) and (ii) above, an FFS-type liquid crystal display element was fabricated in the same manner as in Example 1.

[0323] (iv) Evaluation of adhesion

[0324] Using the weakly anchoring liquid crystal aligning agent (AL-5) prepared in (1) above and the strongly anchoring liquid crystal aligning agent (AL-P1) prepared in (2) above, the evaluation of adhesion was carried out in the same manner as in Example 1. As a result, the evaluation in this example was "good (◎)".

[0325] (v) Evaluation of low-voltage driving

[0326] For the liquid crystal display element manufactured in (iii) above, the evaluation of low-voltage driving was carried out in the same manner as in Example 1. As a result, the evaluation in this example was "good (◎)".

[0327] (vi) Evaluation of liquid crystal alignment (AC afterimage characteristics)

[0328] For the liquid crystal display element manufactured in (iii) above, the evaluation of liquid crystal alignment (AC afterimage characteristics) was carried out in the same manner as in Example 1. As a result, the evaluation in this example was "good (◎)".

[0329] [Example 6, Example 11]

[0330] The polymer and additives contained in the weakly anchoring liquid crystal aligning agent were changed as shown in Table 3 below. Except for this, a liquid crystal aligning agent was prepared in the same manner as in Example 5 to form a liquid crystal alignment film, and a photo-aligned FFS type liquid crystal display element was manufactured and various evaluations were carried out. The evaluation results are shown in Table 3 below.

[0331] [Table 3]

[0332]

[0333] As shown in Table 3, in Examples 1 to 13, any one of adhesion, low-voltage driving, and liquid crystal alignment was evaluated as good or acceptable, achieving a balance of various characteristics. In addition, in Examples 1 to 13, the low-voltage driving of the liquid crystal element and good liquid crystal alignment could be maintained, and at the same time, the adhesion of the liquid crystal alignment film could be improved. Furthermore, by using a crosslinking agent without an aromatic ring, a tendency to further achieve low-voltage driving of the liquid crystal element was observed (Examples 3, 5, 9). In addition, by using an addition polymer as the polymer (P), a tendency was observed that the liquid crystal element was easily driven at low voltage and the liquid crystal alignment became better.

[0334] In contrast, in Comparative Examples 1 to 3, Comparative Example 6, Comparative Example 7 where a polymer having no aliphatic ring with 7 or more ring members was used instead of Polymer (P), and in Comparative Examples 4 and 5 where a polymer having an aliphatic ring with 7 or more ring members in the main chain was used, the evaluation of low-voltage driving of the liquid crystal element and the liquid crystal alignment property was poor, which was worse than that of Examples 1 to 13.

[0335] From the above results, it is clear that the liquid crystal aligning agent according to the present disclosure can exhibit excellent liquid crystal alignment properties, and at the same time can sufficiently achieve low-voltage driving of the liquid crystal element brought about by weak anchoring of the liquid crystal alignment film, and can form a liquid crystal alignment film with excellent adhesion.

Claims

1. A liquid crystal alignment agent for forming a weak anchor film, used for forming a weak anchor liquid crystal alignment film, the liquid crystal alignment agent for forming a weak anchor film containing: The polymer (P) has an aliphatic ring having 7 or more ring members in a side chain; and Cross-linking agent. 2 . The liquid crystal alignment agent for forming a weak anchor film according to claim 1 , wherein the crosslinking agent does not have an aromatic ring. 3 . The liquid crystal alignment agent for forming a weak anchor film according to claim 1 , wherein the polymer (P) is at least one selected from the group consisting of addition polymers, polyamic acid, polyamic acid ester, polyimide, and polyorganosiloxane. 4 . The liquid crystal aligning agent for forming a weak anchor film according to claim 1 , wherein the polymer (P) has an aliphatic ring having 8 or more ring members in a side chain. 5 . The liquid crystal aligning agent for forming a weak anchor film according to claim 1 , further comprising a polymer (Q) having no aliphatic ring having 7 or more ring members in a side chain. 6 . The liquid crystal alignment agent for forming a weak anchor film according to claim 5 , wherein the polymer (Q) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. 7 . A method for manufacturing a liquid crystal alignment film, comprising forming a weak anchor liquid crystal alignment film using the liquid crystal alignment agent according to claim 1 .

8. A method for manufacturing a liquid crystal element, wherein the liquid crystal element comprises 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 comprising the following steps: The weak anchor film-forming liquid crystal alignment agent according to claim 1 or 2 is applied to a surface of at least one of the first substrate and the second substrate to form a weak anchor liquid crystal alignment film.

9. The method for manufacturing a liquid crystal element according to claim 8, wherein The weak anchor liquid crystal alignment film is formed on a surface of one of the first substrate and the second substrate. The method for manufacturing the liquid crystal element further includes the step of forming a strong anchor liquid crystal alignment film having stronger anchoring energy than the weak anchor liquid crystal alignment film on a surface of a substrate different from the substrate on which the weak anchor liquid crystal alignment film is formed, among the first substrate and the second substrate. 10 . The method for manufacturing a liquid crystal element according to claim 9 , wherein the strong anchor liquid crystal alignment film is a rubbed alignment film or a photo-alignment film.

11. The method for manufacturing a liquid crystal element according to claim 9, wherein the first substrate has a pair of electrodes, and the second substrate has no electrodes, forming the strong anchoring liquid crystal alignment film on the surface of the first substrate, The weak anchor liquid crystal alignment film is formed on the surface of the second substrate.

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