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

Abstract

The present invention addresses the problem of providing a liquid crystal element, a liquid crystal aligning agent for forming a weak anchor film, and a method for manufacturing a liquid crystal element, said liquid crystal element being capable of achieving low-voltage driving while maintaining excellent liquid crystal alignment properties, having few residual images, and having excellent adhesion between a liquid crystal alignment film and a sealing material. A liquid crystal element (10) is provided with: a pair of substrates including a first substrate (11) and a second substrate (12); and a liquid crystal layer (13) containing liquid crystal molecules (25). A weakly-anchored liquid crystal alignment film (22) is formed on one of the first substrate (11) and the second substrate (12), and a strongly-anchored liquid crystal alignment film (21) having higher anchoring energy than the weakly-anchored liquid crystal alignment film (22) is formed on the other of the first substrate (11) and the second substrate (12). The weakly anchored liquid crystal alignment film (22) is formed from a liquid crystal alignment agent containing a polyorganosiloxane.

Description

Technical Field

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

[0002] In a liquid crystal element, generally speaking, the initial orientation of the liquid crystal molecules is determined by the anchoring of the liquid crystal molecules by the liquid crystal alignment film. In recent years, in liquid crystal elements of horizontal alignment modes such as in-plane switching (IPS) type or fringe field switching (FFS) type, the following various liquid crystal elements have been proposed: a liquid crystal alignment film with strong anchoring energy (hereinafter also referred to as a "strong anchoring liquid crystal alignment film") is formed on one of a pair of substrates, and a liquid crystal alignment film with no anchoring energy or very low anchoring energy is formed on the other substrate (hereinafter also referred to as a "weak anchoring liquid crystal alignment film"). In a liquid crystal element utilizing a weak anchoring state, compared to a conventional liquid crystal element in which a strong anchoring liquid crystal alignment film is formed on two substrates, further improvements such as an increase in brightness and contrast ratio or low voltage drive, high-speed response (high-speed rise) can be expected. In addition, "weak anchoring" is also called "zero-plane anchoring".

[0003] For example, Patent Document 1 discloses the following: a liquid crystal unit is manufactured by forming a zero-plane anchoring film on a first substrate and forming a liquid crystal alignment film on a second substrate using a known liquid crystal alignment agent, wherein the first method includes the following steps: providing energy sufficient to cause the free radical polymerizable compound to undergo a polymerization reaction while a liquid crystal composition containing a liquid crystal and a free radical polymerizable compound is in contact with a free radical generating film.

[0004] [Prior art literature]

[0005] [Patent Document]

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

[0007] [Problems to be solved by the invention]

[0008] The technology described in Patent Document 1 requires the following steps to produce a weakly anchored liquid crystal alignment film: 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 the radically polymerizable compound to undergo a polymerization reaction. From the perspective of productivity, it is desired to produce a weakly anchored liquid crystal alignment film by simple operation, achieve low-voltage drive derived from the weakly anchored state, and produce a liquid crystal element exhibiting good liquid crystal alignment properties.

[0009] For example, in addition to mobile applications represented by smart phones or tablet personal computers (personal computers, PCs), in large televisions or PC monitors, from the perspective of design or the miniaturization of display devices, narrow frame is achieved. As one of the methods for achieving narrow frame, the following method is known: after forming a liquid crystal alignment film on the entire substrate surface, a sealing material is applied to the liquid crystal alignment film to adhere the substrates to each other. On the other hand, if a sealing material is configured on the liquid crystal alignment film, the adhesion between the substrates is easily reduced, and there is a concern that the substrate will peel off easily due to the action of external forces.

[0010] Furthermore, as liquid crystal elements become more versatile, there is a demand to minimize residual images in liquid crystal elements in order to achieve higher quality. However, it is difficult to simultaneously satisfy these multiple characteristics, and there is room for further improvement in liquid crystal aligning agents and liquid crystal elements.

[0011] The present invention has been developed in light of the above-mentioned problems, and one of its objects is to provide a liquid crystal element that can achieve low-voltage drive, little afterimage, and excellent adhesion between the liquid crystal alignment film and the sealant while maintaining excellent liquid crystal orientation. Another object of the present invention is to provide a liquid crystal alignment agent for forming a weak anchor film, which can produce a liquid crystal element that can achieve low-voltage drive, little afterimage, and excellent adhesion between the liquid crystal alignment film and the sealant while maintaining excellent liquid crystal orientation.

[0012] [Technical means to solve the problem]

[0013] According to the present invention, in one form, a liquid crystal element is provided, which includes: a pair of substrates, including a first substrate and a second substrate; and a liquid crystal layer, including liquid crystal molecules, a weakly anchored liquid crystal orientation film is formed on one of the first substrate and the second substrate, and a strongly anchored liquid crystal orientation film having an anchoring energy stronger than that of the weakly anchored liquid crystal orientation film is formed on the other substrate, and the weakly anchored liquid crystal orientation film is formed by a liquid crystal orientation agent including polyorganosiloxane.

[0014] According to another aspect of the present invention, there is provided a liquid crystal alignment agent for forming a weak anchor film, which is used to form a weak anchor liquid crystal alignment film, and the liquid crystal alignment agent for forming a weak anchor film contains polyorganosiloxane.

[0015] In addition, according to the present invention, in another form, a method for manufacturing a liquid crystal element is provided, comprising: a process of forming a weakly anchored liquid crystal orientation film on one of a pair of substrates using the liquid crystal orientation agent for forming the weakly anchored film; and a process of forming a strongly anchored liquid crystal orientation film having an anchoring energy stronger than that of the weakly anchored liquid crystal orientation film on the other substrate.

[0016] [Effects of the Invention]

[0017] According to the present invention, a liquid crystal element can be obtained that can achieve low-voltage drive, little afterimage, and excellent adhesion between the liquid crystal alignment film and the sealant while maintaining excellent liquid crystal orientation. Furthermore, a liquid crystal alignment agent for forming a weak anchor film can be obtained, which can achieve low-voltage drive, little afterimage, and excellent adhesion between the liquid crystal alignment film and the sealant while maintaining excellent liquid crystal orientation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of an FFS type liquid crystal element.

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

[0020] Figure 3 This is a diagram showing four systems of driving electrodes.

[0021] [Explanation of symbols]

[0022] 10: Liquid crystal element

[0023] 11: First substrate

[0024] 12: Second substrate

[0025] 13: Liquid crystal layer

[0026] 14: Common electrode

[0027] 15: Insulation film

[0028] 16: Pixel electrode

[0029] 17: Color filter

[0030] 18: External coating

[0031] 19: Slit

[0032] 20: Top electrode

[0033] 21, 22: Liquid crystal alignment film

[0034] 23, 24: Polarizing plate

[0035] 25: Liquid crystal molecules

[0036] C1: The part surrounded by the dotted line

[0037] d1: electrode line width

[0038] d2: distance between electrodes DETAILED DESCRIPTION

[0039] Hereinafter, matters related to the embodiment will be described in detail. In addition, in this specification, the numerical range described using "to" means that the numerical values described before and after "to" are included as the lower limit and upper limit. The so-called "structural unit" refers to a unit that mainly constitutes the main chain structure, and is a unit that contains at least two or more in the main chain structure. Typically, a structural unit is a repeating unit composed of a monomer. In addition, a structural unit can also be obtained by reacting a repeating unit having a reactive group with a compound having a functional group that can react with the reactive group.

[0040] In this specification, the term "hydrocarbon group" means a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group. The so-called "chain hydrocarbon group" refers to a straight-chain hydrocarbon group and a branched hydrocarbon group that does not contain a ring structure but only a chain structure. The chain hydrocarbon group may be saturated or unsaturated. The so-called "alicyclic hydrocarbon group" refers to a hydrocarbon group that only contains an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. The alicyclic hydrocarbon group does not need to contain only an alicyclic hydrocarbon structure, but also includes a group having a chain structure in a part thereof. The so-called "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. The aromatic hydrocarbon group does not need to contain only an aromatic ring structure, but also may contain a chain structure or an alicyclic hydrocarbon structure in a part thereof. The so-called "organic group" refers to an atomic group formed by removing any hydrogen atom from a compound containing carbon (i.e., an organic compound).

[0041] The so-called "main chain" of a polymer refers to the part of the "trunk" containing the longest chain of atoms in the polymer. The part of the "trunk" is allowed to contain a ring 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" refers to the part branching from the "trunk" part of the polymer. "(Meth)acrylic group" is a term that includes acrylic group and methacrylic group, and "(meth)acryloyl" is a term that includes acryloyl and methacryloyl. "(Meth)acrylate" is a term that includes acrylate and methacrylate. "Epoxy" is a term that includes oxacyclopropyl and oxetane.

[0042] Liquid Crystal Element

[0043] Hereinafter, an embodiment in which the liquid crystal element of the present disclosure is embodied as a fringe field switching (FFS) type liquid crystal element will be described with reference to the accompanying drawings as appropriate.

[0044] The FFS type liquid crystal element, which is one of the liquid crystal elements of the transverse electric field type, is a liquid crystal element that controls the transmission of light by applying a fringe electric field to the liquid crystal molecules in a parallel (homogeneous) orientation. Figure 1 As shown, the liquid crystal element 10 includes: a pair of substrates including a first substrate 11 and a second substrate 12 ; and a liquid crystal layer 13 disposed between the pair of substrates and including liquid crystal molecules 25 .

[0045] The first substrate 11 and the second substrate 12 are transparent substrates and are formed of glass substrates or resin films. Examples of the resin forming the substrates include various materials such as silicon, polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, polypropylene, polyvinyl chloride, aromatic polyamide, polyamideimide, polyimide, triacetyl cellulose (TAC), and polymethyl methacrylate.

[0046] Scan lines, common wiring, and signal lines (not shown) are provided on the surface of the first substrate 11. A common electrode 14 serving as a surface electrode connected to the common wiring is provided in the area divided by the scan lines and the common wiring. In addition, in the first substrate 11, a comb-shaped pixel electrode 16 is provided on the common electrode 14 with an insulating film 15 interposed therebetween. An electrode pair is constructed by these common electrodes 14 and pixel electrodes 16. The common electrode 14 and the pixel electrode 16 are, for example, a NESA film (a registered trademark of PPG, Inc., USA) containing tin oxide (SnO2), an indium tin oxide (ITO) film containing indium oxide-tin oxide (In2O3-SnO2), or a transparent conductive film containing a carbon material. A thin film transistor (TFT) (not shown) serving as a switching element is provided near the intersection of the scan lines and the signal lines, and the application and release of voltage to the common electrode 14 and the pixel electrode 16 are controlled by driving the TFT.

[0047] A liquid crystal orientation film 21 is formed on the surface of the slit 19 between the pixel electrodes 16 and the pixel electrodes 16 in the first substrate 11. The liquid crystal orientation film 21 is a strongly anchored liquid crystal orientation film. Here, the "strongly anchored liquid crystal orientation film" is a film that can uniaxially orient the liquid crystal molecules near the liquid crystal orientation film when an electric field is applied. In the present embodiment, the liquid crystal orientation film 21 is formed by a liquid crystal orientation agent for horizontal orientation, which can form a state in which the slow axis of the liquid crystal molecules 25 is arranged roughly parallel to the substrate surface when no voltage is applied between the electrodes. Here, the so-called "horizontal orientation" refers to a state in which the slow axis of the liquid crystal molecules 25 is arranged roughly parallel to the substrate surface. Therefore, the situation in which the slow axis of the liquid crystal molecules 25 is slightly tilted (preferably less than 10°) relative to the substrate surface is also included in the concept of horizontal orientation. In addition, the state in which the slow axis of the liquid crystal molecules 25 is arranged roughly perpendicular to the substrate surface is called "vertical orientation".

[0048] The liquid crystal alignment film 21 may be a film formed of a liquid crystal alignment agent that has not been subjected to an alignment treatment such as a rubbing treatment or a photo-alignment treatment. Preferably, the film formed of a liquid crystal alignment agent is a rubbed alignment film or a photo-alignment film.

[0049] A color filter 17 and an outer coating film 18 are provided on the surface of the second substrate 12. A liquid crystal orientation film 22 is formed on the surface of the outer coating film 18 in the second substrate 12. The liquid crystal orientation film 22 is a weakly anchored liquid crystal orientation film. Here, the "weakly anchored liquid crystal orientation film" is a film that has no orientation restriction force on the liquid crystal molecules 25 in the in-plane direction, or even if there is an orientation restriction force on the liquid crystal molecules 25 in the in-plane direction, it is smaller than the intermolecular force between the liquid crystals, and the liquid crystal molecules 25 cannot be uniaxially oriented in any direction by the liquid crystal orientation film alone. Therefore, in a weakly anchored state, the orientation direction in the plane can be freely rotated 360° by control based on an external field such as an electric field / magnetic field. The liquid crystal orientation film 22 is preferably a film that has not been subjected to an orientation treatment.

[0050] The first substrate 11 and the second substrate 12 are arranged to be separated by a predetermined gap (cell gap) through a spacer (not shown). Examples of the spacer include columnar spacers and beaded spacers. The first substrate 11 and the second substrate 12 are bonded to each other's peripheries via a sealant. The liquid crystal layer 13 is formed by filling the space surrounded by the first substrate 11, the second substrate 12, and the sealant with a liquid crystal composition.

[0051] A more detailed explanation of "weakly anchored liquid crystal alignment films" and "strongly anchored liquid crystal alignment films" is provided. The difference between "weakly anchored liquid crystal alignment films" and "strongly anchored liquid crystal alignment films" lies in the different alignment restraining forces that constrain the alignment direction of liquid crystal molecules. Specifically, the alignment restraining force of liquid crystal molecules in a weakly anchored liquid crystal alignment film is essentially zero in the in-plane direction. In contrast, a strongly anchored liquid crystal alignment film has a stronger anchoring energy than a weakly anchored liquid crystal alignment film.

[0052] More specifically, in a liquid crystal cell, when the orientation of the liquid crystal molecules near the alignment film is controlled by a strong anchoring liquid crystal alignment film, when an electric field is applied, the liquid crystal molecules at the interface between the liquid crystal layer and the liquid crystal alignment film maintain the orientation direction before the electric field was applied while being subject to the orientation constraint force brought by the liquid crystal alignment film. In contrast, a weak anchoring liquid crystal alignment film has no orientation constraint force on the liquid crystal molecules at the interface between the liquid crystal layer and the liquid crystal alignment film, or even if it does, it is very weak, and the orientation direction of the liquid crystal molecules is easily changed by the application of an electric field. Due to the weak anchoring of the liquid crystal alignment film, in the liquid crystal alignment film, not only the orientation constraint force of the liquid crystal molecules in the horizontal direction is reduced, but also the orientation constraint force of the liquid crystal molecules in the vertical direction is reduced. Therefore, it is believed that according to a liquid crystal cell including a weak anchoring liquid crystal alignment film, low voltage can be achieved when driving the liquid crystal molecules.

[0053] In addition, in a conventional liquid crystal element, the orientation of the liquid crystal molecules is controlled by a pair of liquid crystal alignment films (strong anchor liquid crystal alignment films), and the orientation of the liquid crystal molecules can also be controlled by combining a weak anchor liquid crystal alignment film and a strong anchor liquid crystal alignment film as in the liquid crystal element 10. For example, in Figure 1 In that case, when a pair of electrodes are provided, a strongly anchored liquid crystal orientation film is formed on the side of the first substrate 11 (electrode substrate) by a liquid crystal orientation agent for horizontal orientation, and a weakly anchored liquid crystal orientation film is formed on the side of the second substrate 12 (opposite substrate), when the liquid crystal element is not driven, the liquid crystal molecules 25 are formed in the entire liquid crystal layer in a horizontally oriented state.

[0054] Polarizers 23 and 24 are disposed on the outer sides of the first substrate 11 and the second substrate 12, respectively. A terminal region is provided on the outer edge of the first substrate 11, and the liquid crystal element 10 is driven by connecting a driver integrated circuit (IC) for driving the liquid crystal to the terminal region. In detail, when a voltage is applied to the electrode pair to form an electric field (fringe electric field) between the common electrode 14 and the pixel electrode 16, the electric field is directed toward the common electrode 14 on both sides of the pixel electrode 16, thereby causing not only the liquid crystal molecules between the pixel electrodes to swirl, but also the liquid crystal molecules on the pixel electrodes to swirl. Therefore, according to the FFS type liquid crystal element, there is an advantage of being able to achieve a wider viewing angle and high contrast.

[0055] In addition, the case where the liquid crystal element of the present invention is an FFS type liquid crystal element is described, but the driving mode of the liquid crystal element of the present invention is not limited to the FFS type. For example, it can be applied to 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, optically compensated bending (OCB) type, polymer stabilized alignment (PSA) type, electrically controlled birefringence (ECB) type and other modes. Among these, a horizontally aligned liquid crystal element such as IPS type or FFS type is preferred.

[0056] Liquid crystal alignment agent for weak anchor film formation

[0057] Next, the liquid crystal alignment agent for forming a weak anchor film (hereinafter also referred to as "liquid crystal alignment agent") of the present disclosure, used in forming a weak anchor liquid crystal alignment film, will be described. The liquid crystal alignment agent of the present disclosure contains a polyorganosiloxane as a polymer component. Each component may be used alone or in combination of two or more unless otherwise specified.

[0058] <Polyorganosiloxane>

[0059] The polyorganosiloxane (hereinafter also referred to as "polyorganosiloxane (PS)") contained in the liquid crystal aligning agent of the present disclosure is a polymer having a siloxane bond in its main skeleton. Examples of polyorganosiloxane (PS) include hydrolysis-condensation products obtained by hydrolyzing a hydrolyzable silane compound (e.g., an alkoxysilane compound). As long as the polyorganosiloxane (PS) contains two or more structural units having a siloxane bond in its main chain, it may be an oligomer having, for example, 3 to 20 repeating units, or a polymer having a higher molecular weight than the oligomer.

[0060] The structure of polyorganosiloxane (PS) is not particularly limited, and examples thereof include polyorganosiloxanes having a random structure, a ladder structure, a cage structure, an incomplete cage structure, a cyclic structure, and the like. In terms of obtaining a film that can well maintain the orientation of the liquid crystal while fully realizing low-voltage driving of the liquid crystal element, among these, polyorganosiloxane (PS) preferably has at least one of a cage structure, an incomplete cage structure, and a cyclic structure. In addition, the structure of the polyorganosiloxane can be 29 The product was identified by Si-Nuclear Magnetic Resonance (NMR) and molecular weight determination.

[0061] The polyorganosiloxane (PS) may have a side chain. Examples of the side chain possessed by the polyorganosiloxane (PS) include monovalent organic groups having 1 to 30 carbon atoms. Specifically, the side chains include monovalent hydrocarbon groups having 1 to 30 carbon atoms, monovalent hydrocarbon groups having 1 to 30 carbon atoms with a substituent, and any methylene group in a monovalent hydrocarbon group having 2 to 30 carbon atoms, which is replaced by -O-, -S-, -CO-, -COO-, -OCO-, -NR- 10 -、-NR 10 -CO-, -CO-NR 10 -、-O-CO-NR 10 -、-NR 10 -CO-O- or -NR 10 -CO-NR 11 -, etc., and any hydrogen atom in the above group is substituted by a substituent. 10 and R 11 Each of them is independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0062] Examples of the monovalent hydrocarbon group having 1 to 30 carbon atoms include a linear or branched monovalent saturated hydrocarbon group having 1 to 30 carbon atoms, a linear or branched monovalent unsaturated hydrocarbon group having 2 to 30 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms.

[0063] Specific examples of linear or branched monovalent saturated hydrocarbon groups having 1 to 30 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl. Specific examples of linear or branched unsaturated hydrocarbon groups having 2 to 30 carbon atoms include alkenyl groups such as vinyl, 1-propenyl, 2-propenyl, 1-butenyl, and 2-butenyl; and alkynyl groups such as ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, and 2-butynyl.

[0064] Examples of the monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms include aliphatic hydrocarbon groups having a monocyclic hydrocarbon structure having 3 to 30 carbon atoms or a polycyclic hydrocarbon structure having 6 to 30 carbon atoms as a ring structure. The monocyclic hydrocarbon structure having 3 to 30 carbon atoms and the polycyclic hydrocarbon structure having 6 to 30 carbon atoms may be either saturated or unsaturated. Specific examples of the ring contained in the alicyclic hydrocarbon group include a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a cyclopentene ring, a cyclohexene ring, a cycloheptene ring, a cyclooctene ring, a cyclodecene ring, a norbornane ring, a bicyclo[2.2.2]octane ring, and an adamantane ring. The monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms in the side chain of the polyorganosiloxane (PS) may have only one aliphatic hydrocarbon ring or may have two or more.

[0065] Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include hydrocarbon groups having an aromatic monocyclic hydrocarbon structure having 6 to 30 carbon atoms or an aromatic polycyclic hydrocarbon structure having 6 to 30 carbon atoms as a ring structure. Specific examples of the ring contained in the aromatic hydrocarbon group include a benzene ring, a naphthalene ring, an anthracene ring, an indene ring, and a fluorene ring. The monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms in the side chain of the polyorganosiloxane (PS) may have only one ring (the total of the aromatic hydrocarbon ring and the aliphatic hydrocarbon ring) or may have two or more rings.

[0066] When the side chain of the polyorganosiloxane (PS) has a substituent, examples of the substituent include a halogen atom (eg, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), a hydroxyl group, a cyano group, a nitro group, a carboxyl group, and an amino group.

[0067] The side chain of polyorganosiloxane (PS) may be a liquid crystal orientation group or a photo-orientation group. Here, in this specification, the so-called "liquid crystal orientation group" refers to a group that can impart liquid crystal orientation ability to the film without relying on light irradiation. Specific examples of liquid crystal orientation groups include: alkyl groups having 4 to 30 carbon atoms, alkoxy groups having 4 to 30 carbon atoms, fluoroalkyl groups having 4 to 30 carbon atoms, fluoroalkoxy groups having 4 to 30 carbon atoms, polyalkyleneoxy groups having 4 to 30 carbon atoms, groups having a mesogenic structure formed by directly or via a divalent linking group (for example, the heteroatom-containing group) having two or more rings (preferably at least one ring selected from the group consisting of a cyclohexane ring, a benzene ring, and a naphthalene ring), and groups having a steroid skeleton.

[0068] The photo-alignment group is a group that can impart anisotropy to the film through a photoreaction such as a photoisomerization reaction, a photodimerization reaction, a photo-Fries rearrangement reaction, or a photodecomposition reaction caused by light irradiation. Specific examples of the photo-alignment group include: an azobenzene-containing group having azobenzene or a derivative thereof as a basic skeleton, a cinnamic acid structure-containing group having cinnamic acid or a derivative thereof (cinnamic acid structure) as a basic skeleton, a chalcone-containing group having chalcone or a derivative thereof as a basic skeleton, a benzophenone-containing group having benzophenone or a derivative thereof as a basic skeleton, a coumarin-containing group having coumarin or a derivative thereof as a basic skeleton, a cyclobutane-containing structure having cyclobutane or a derivative thereof as a basic skeleton, a stilbene-containing group having stilbene or a derivative thereof as a basic skeleton, and a phenyl benzoate-containing group having phenyl benzoate or a derivative thereof as a basic skeleton.

[0069] In the case where the polyorganosiloxane (PS) has a monovalent organic group with 1 to 30 carbon atoms in the side chain, a liquid crystal alignment film can be formed that exhibits excellent liquid crystal alignment while fully realizing low-voltage driving of the liquid crystal element. In terms of further enhancing the effect of the weak anchoring property of the film, the polyorganosiloxane (PS) preferably has an alkyl group with 1 to 30 carbon atoms, a "*-R 2 -(OR 3 ) r -OR 4 " a group having 2 to 30 carbon atoms (wherein R 2 and R 3 are independently an alkanediyl group, r is an integer greater than or equal to 0, and when r is 0, R 4 is an alkyl group, and when r is 1 or more, R 4 is a hydrogen atom or an alkyl group; the same applies hereinafter) or a monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms and one aliphatic hydrocarbon ring (hereinafter, these are also included and referred to as "specific groups").

[0070] Here, "having a specific group in the side chain" means an alkyl group having 1 to 30 carbon atoms, "*-R 2 -(OR 3 ) r -OR 4The group having 2 to 30 carbon atoms represented by " or the monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms in which the number of aliphatic hydrocarbon rings is 1 is bonded to an atom (preferably a silicon atom) constituting the main chain of the polyorganosiloxane directly or via a divalent linking group. Examples of the divalent linking group include: the aforementioned heteroatom-containing group, a group in which a methylene group in a divalent aliphatic hydrocarbon group having 2 to 10 carbon atoms is substituted by the aforementioned heteroatom-containing group, and a group in which any hydrogen atom of the aforementioned group is substituted. Examples of the substituent include a halogen atom, a hydroxyl group, and the like.

[0071] The alkyl group having 1 to 30 carbon atoms may be linear or branched. Specific examples of the alkyl group having 1 to 30 carbon atoms include groups exemplified as linear or branched saturated hydrocarbon groups having 1 to 30 carbon atoms. The alkyl group in the side chain of the polyorganosiloxane (PS) preferably has 3 or more carbon atoms, more preferably 4 or more carbon atoms, and further preferably 5 or more carbon atoms. In addition, from the perspective of suppressing the pretilt angle of the liquid crystal molecules near the weakly anchored liquid crystal alignment film from becoming too high, the alkyl group in the side chain of the polyorganosiloxane (PS) preferably has 25 or less carbon atoms, more preferably 20 or less carbon atoms, and further preferably 17 or less carbon atoms.

[0072] More specifically, regarding the alkyl group in the side chain of the polyorganosiloxane (PS), when the alkyl group is linear, the number of carbon atoms in the linear alkyl group is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. Furthermore, the number of carbon atoms in the linear alkyl group is preferably 20 or less, more preferably 17 or less, even more preferably 15 or less, and even more preferably 11 or less.

[0073] When the alkyl group in the side chain of the polyorganosiloxane (PS) is branched, the number of carbon atoms in the longest portion of the branched alkyl group is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. Furthermore, the number of carbon atoms in the longest portion of the branched alkyl group is preferably 20 or less, more preferably 17 or less, even more preferably 15 or less, and even more preferably 11 or less. For example, when a 1-hexylnonyl group is introduced into the side chain of the polyorganosiloxane, the number of carbon atoms in the longest portion of the 1-hexylnonyl group is 9.

[0074] As "*-R 2 -(OR 3 ) r -OR 4 " The group having 2 to 30 carbon atoms represented by " may include an alkoxyalkyl group having 2 to 30 carbon atoms, a polyalkyleneoxy group having 3 to 30 carbon atoms, and the like. Among these, specific examples of the alkoxyalkyl group having 2 to 30 carbon atoms include a group in which one methylene group in an alkyl group having 3 to 30 carbon atoms is substituted with -O-. In the case of a polyalkyleneoxy group having 3 to 30 carbon atoms (i.e., when r is 1 or more), R 2or R 3 It can be straight chain or branched. 4 Specific examples of the polyalkyleneoxy group include a group having a polyethylene oxide structure, a group having a polypropylene oxide structure, and a group having a polyethylene oxide structure and a polypropylene oxide structure.

[0075] Examples of monovalent alicyclic hydrocarbon groups having 3 to 30 carbon atoms and having one aliphatic hydrocarbon ring include groups having a saturated chain hydrocarbon ring having 3 to 12 carbon atoms as the aliphatic hydrocarbon ring. Examples of aliphatic hydrocarbon rings include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, cycloheptane rings, cyclooctane rings, cyclononane rings, and cyclodecane rings. In order to reduce the anchoring force of the liquid crystal, aliphatic hydrocarbon rings other than the cyclohexane ring are preferred, aliphatic hydrocarbon rings having 7 or more ring members are more preferred, and aliphatic hydrocarbon rings having 7 to 12 ring members are even more preferred. The monovalent alicyclic hydrocarbon group may have a substituent in the ring portion. Examples of such substituents include a methyl group, an ethyl group, a propyl group, and a halogen atom.

[0076] In terms of further improving the effect of low-voltage driving, the side chain of the polysiloxane (PS) is preferably at least one of an alkyl group having 1 to 30 carbon atoms and a saturated chain hydrocarbon ring group having 7 to 12 carbon atoms, more preferably an alkyl group having 3 or more carbon atoms, and even more preferably an alkyl group having 5 or more carbon atoms.

[0077] On the other hand, from the viewpoint of suppressing the increase in the pretilt angle of the liquid crystal molecules present in the vicinity of the film formed using polyorganosiloxane (PS) and improving the effect of showing the weak anchoring characteristics, polyorganosiloxane (PS) preferably does not have one or more of the partial structures in which a photo-alignment group, a benzene ring, and two or more cyclohexane rings are bonded by a single bond, -COO-, or -NR- (wherein R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms), more preferably does not have two or more, and even more preferably does not have all three.

[0078] Specifically, a preferred embodiment of the polyorganosiloxane (PS) is a polymer containing a structural unit represented by the following formula (S-1).

[0079] [Chemistry 1]

[0080]

[0081] (In formula (S-1), R 1 is an alkyl group with 1 to 30 carbon atoms, "*-R 2 -(OR 3 ) r -OR 4" is a monovalent group bonded to a silicon atom via a single bond or a divalent linking group, wherein R 2 and R 3 are independently alkanediyl; r is an integer greater than 0; when r is 0, R 4 is an alkyl group, and when r is 1 or more, R 4 is a hydrogen atom or an alkyl group)

[0082] In the formula (S-1), R 1 Specific examples and preferred examples of include the same groups as described as preferred specific examples of the group contained in the side chain of polyorganosiloxane (PS).

[0083] In the polyorganosiloxane (PS), the structural unit derived from the above formula (S-1) 29 The integral ratio of the peak of the Si-NMR spectrum is preferably 70% to 99%, more preferably 80% to 99%, and even more preferably 90% to 99%. 29 The integral ratio of the peaks in the Si-NMR spectrum represents the content ratio of the structural unit represented by the formula (S-1) in the polyorganosiloxane. A larger value indicates a higher content ratio of the structural unit represented by the formula (S-1).

[0084] Another preferred embodiment of the polyorganosiloxane (PS) is a cyclic polysiloxane having a molecular weight of 1,500 or less. The cyclic polysiloxane as the polyorganosiloxane (PS) is represented by the following formula (S-3), for example.

[0085] [Chemistry 2]

[0086]

[0087] (In formula (S-3), R 11 ~R 16 are independently hydrogen atoms or monovalent organic groups; wherein, R 11 ~R 16 At least one of them is an alkyl group with 1 to 30 carbon atoms, "*-R 2 -(OR 3 ) r -OR 4 " is a monovalent group bonded to a silicon atom via a single bond or a divalent linking group, wherein R 2 、R 3 、R 4and r has the same meaning as in the formula (S-1); n is an integer from 1 to 18; when n is 2 or more, multiple R 11 Same or different, multiple R 12 Same or Different)

[0088] As the polyorganosiloxane (PS), the reaction product of a polyorganosiloxane having an epoxy group (hereinafter also referred to as a "reactive polyorganosiloxane") and a carboxylic acid having a specific group (hereinafter also referred to as a "specific aliphatic carboxylic acid") can be preferably used. The reactive polyorganosiloxane preferably has at least one of a cage structure, an incomplete cage structure, and a cyclic structure. Specifically, the reactive polyorganosiloxane is preferably a polyorganosiloxane containing a structural unit represented by the following formula (S-2) or a cyclic polysiloxane having an epoxy group.

[0089] [Chemistry 3]

[0090]

[0091] (In formula (S-2), Y 1 is a monovalent group having an epoxy group)

[0092] In the formula (S-2), Y 1 Examples of the monovalent group represented by the compound include a group having a glycidyl group or a 3,4-epoxycyclohexyl group. Specific examples include a glycidyloxymethyl group, a 2-glycidyloxyethyl group, a 3-glycidyloxypropyl group, a 4-glycidyloxybutyl group, a 2-(3,4-epoxycyclohexyl)ethyl group, a 3-(3,4-epoxycyclohexyl)propyl group, and a 4-(3,4-epoxycyclohexyl)butyl group.

[0093] As a cyclic polysiloxane which has an epoxy group, the compound represented by following formula (S-4) is mentioned, for example.

[0094] [Chemistry 4]

[0095]

[0096] (In formula (S-4), Y 11 ~Y 16 are independently hydrogen atoms or monovalent organic groups; wherein, Y 11 ~Y 16 At least one of them is a monovalent group having an epoxy group; n is an integer of 1 to 18; when n is 2 or more, multiple Y 11 Same or different, multiple Y 12 Same or Different)

[0097] In the formula (S-4), Y 11 ~Y 16Specific examples of the monovalent group having an epoxy group include a glycidyl group or a 3,4-epoxycyclohexyl group. 1 The groups exemplified as the monovalent groups represented by are the same groups.

[0098] Specific examples of cyclic polysiloxanes having an epoxy group include compounds represented by the following formulas (A-1) to (A-5). Commercially available products may also be used as cyclic polysiloxanes having an epoxy group. Examples of commercially available products include CS-697 and CS-783 (manufactured by Sigma-Aldrich), KR-470, X-40-2670, and X-40-2678 (manufactured by Shin-Etsu Silicones Co., Ltd.).

[0099] [Chemistry 5]

[0100]

[0101] (In formulas (A-1) to (A-5), m is an integer from 0 to 17)

[0102] Examples of the specific aliphatic carboxylic acid include an alkyl group having 1 to 30 carbon atoms, "*-R 2 -(OR 3 ) r -OR 4 " is a compound in which each of the groups exemplified is bonded to a carboxyl group and is a group having 2 to 30 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms and having one aliphatic hydrocarbon ring. In terms of being able to more highly balance liquid crystal orientation and low-voltage driving, the specific aliphatic carboxylic acid is preferably an alkyl group having 1 to 30 carbon atoms, an alkoxyalkyl group having 2 to 30 carbon atoms, or a monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms and containing one aliphatic hydrocarbon ring, and is more preferably an aliphatic carboxylic acid having an alkyl group having 1 to 30 carbon atoms. Specific examples and preferred examples of the alkyl group having 1 to 30 carbon atoms contained in the aliphatic carboxylic acid include the same examples as described above.

[0103] <Synthesis of polyorganosiloxane>

[0104] The method for synthesizing polyorganosiloxane (PS) is not particularly limited. For example, polyorganosiloxane (PS) can be obtained by using a compound having an alkoxysilyl group (hereinafter also referred to as an "alkoxysilane compound") as a raw material and performing a hydrolysis / condensation reaction of the alkoxysilane compound. Specifically, the following methods [1s] and [2s] are exemplified.

[0105] [1s] A method of synthesizing a reactive polyorganosiloxane by hydrolyzing and condensing a hydrolyzable silane compound (ms-1) having an epoxy group or a mixture of the silane compound (ms-1) and other silane compounds, and then reacting the obtained reactive polyorganosiloxane with a carboxylic acid having a monovalent organic group having 1 to 30 carbon atoms (hereinafter also referred to as "side chain-introduced carboxylic acid").

[0106] [2s] A method of hydrolyzing and condensing a hydrolyzable silane compound (ms-2) having a monovalent organic group having 1 to 30 carbon atoms or a mixture of the silane compound (ms-2) and other silane compounds.

[0107] Among these, the method [1s] is preferred in that it is simple and can increase the rate of introduction of side chains into the polyorganosiloxane (PS).

[0108] Specific examples of the silane compound (ms-1) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethylmethyldimethoxysilane, 2-glycidoxyethyldimethylmethoxysilane, 2-glycidoxyethyldimethylethyl Oxysilane, 4-glycidyloxybutyltrimethoxysilane, 4-glycidyloxybutylmethyldimethoxysilane, 4-glycidyloxybutylmethyldiethoxysilane, 4-glycidyloxybutyldimethylmethoxysilane, 4-glycidyloxybutyldimethylethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(3,4-epoxycyclohexyl)propyltrimethoxysilane, etc.

[0109] The other silane compounds used in the synthesis of the reactive polyorganosiloxane are not particularly limited as long as they are hydrolyzable. Specific examples include alkoxysilanes such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxysilane;

[0110] Alkoxysilanes containing nitrogen or sulfur atoms, such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(3-cyclohexylamino)propyltrimethoxysilane, and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane;

[0111] Alkoxysilanes containing unsaturated hydrocarbons such as 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 6-(meth)acryloyloxyhexyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and p-phenylenediaminetrimethoxysilane; trimethoxysilylpropylsuccinic anhydride, etc.

[0112] 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 ratio of water used is preferably 1 to 30 moles relative to 1 mole of the silane compound (total amount). As the catalyst used, for example, there can be mentioned: acids, alkali metal compounds, organic bases, titanium compounds, zirconium compounds, etc. The amount of the catalyst used varies depending on the reaction conditions such as the type of catalyst and temperature, and can be appropriately set. Relative to the total amount of the silane compound, the amount of the catalyst used is preferably 0.01 times the mole to 3 times the mole. As the organic solvent used, for example, there can be mentioned: hydrocarbons, ketones, esters, ethers, alcohols, etc. Among these, it is preferred to use a water-insoluble or poorly water-soluble organic solvent. Relative to a total of 100 parts by mass of the silane compound used in the reaction, the ratio of the organic solvent used is preferably 10 parts by mass to 10,000 parts by mass.

[0113] The hydrolysis / condensation reaction is preferably carried out by heating, for example, in an oil bath. The heating temperature is preferably set to 130°C or less, and the heating time is preferably set to 0.5 to 12 hours. After the reaction is completed, the organic solvent layer separated from the reaction solution is optionally dried using a desiccant to remove the solvent, thereby obtaining the target polyorganosiloxane. The synthesis method of the polyorganosiloxane is not limited to the hydrolysis / condensation reaction described above; for example, the method can be carried out by reacting a hydrolyzable silane compound in the presence of oxalic acid and an alcohol.

[0114] In the method [1s] described above, the reactive polyorganosiloxane obtained by the above reaction is then reacted with a carboxylic acid having a side chain. This allows the epoxy groups of the reactive polyorganosiloxane to react with the carboxyl groups of the carboxylic acid having a side chain, thereby obtaining a polyorganosiloxane (PS) having a desired structure in the side chain. Specific examples of the carboxylic acid having a side chain include carboxylic acids having the specific examples and preferred examples listed as monovalent organic groups having 1 to 30 carbon atoms that can be included in the side chain of the polyorganosiloxane (PS).

[0115] Relative to the silicon atoms possessed by polyorganosiloxane (PS), the content ratio of the monovalent organic group having 1 to 30 carbon atoms in one molecule of polyorganosiloxane (PS) is preferably 1 mol% or more, more preferably 5 mol% or more, further preferably 10 mol% or more, further more preferably 15 mol% or more. In addition, relative to the silicon atoms possessed by polyorganosiloxane (PS), the content ratio of the monovalent organic group having 1 to 30 carbon atoms in one molecule of polyorganosiloxane (PS) is preferably 90 mol% or less, more preferably 80 mol% or less. By having the content ratio of the monovalent organic group having 1 to 30 carbon atoms in polyorganosiloxane (PS) be within the range, a liquid crystal element having excellent liquid crystal orientation while fully realizing low-voltage driving of the liquid crystal element can be obtained, which is preferred in this respect.

[0116] The reaction of the reactive polyorganosiloxane with the carboxylic acid introduced into the side chain is preferably carried out in the presence of a catalyst and an organic solvent. Examples of the catalyst include organic bases and compounds known as curing accelerators that accelerate the reaction of epoxy compounds (e.g., tertiary organic amines, quaternary organic amines, quaternary ammonium salts, etc.). The amount of catalyst used is preferably 100 parts by mass or less, more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the reactive polyorganosiloxane.

[0117] As the organic solvent used in the reaction, for example, hydrocarbons, ethers, esters, ketones, amides, alcohols, etc. can be mentioned. The organic solvent is preferably used at a solid content concentration (the ratio of the total mass of the components other than the solvent in the reaction solution to the total weight of the solution) of 0.1% by mass or more, and more preferably used at a solid content concentration (the ratio of the total mass of the components other than the solvent in the reaction solution to the total weight of the solution) of 5% to 50% by mass. In addition, the reaction solvent may also contain an organic solvent and a small amount of water. In the reaction, the reaction temperature is preferably 0°C to 200°C, more preferably 50°C to 150°C. The reaction time is preferably 0.1 hours to 50 hours, more preferably 0.5 hours to 20 hours. After the reaction is completed, it is preferred to use water to wash the organic solvent layer obtained by separating from the reaction solution. After washing with water, the organic solvent layer is dried with an appropriate desiccant as needed to remove the solvent, thereby obtaining a polyorganosiloxane (PS) with the desired side chains introduced.

[0118] The polyorganosiloxane (PS) preferably has a solution viscosity of 1 to 500 mPa·s, more preferably 3 to 200 mPa·s, when it is prepared as a 10% by mass solution.

[0119] The molecular weight of polyorganosiloxane (PS) can be suitably set according to the structure of polyorganosiloxane (PS). For example, when polyorganosiloxane (PS) has any one of a cage structure and an incomplete cage structure, from the viewpoint of film forming properties, the weight average molecular weight (Mw) of polyorganosiloxane (PS) is preferably 1,000 or more, more preferably 1,500 or more, and further preferably 2,000 or more. In addition, from the viewpoint of obtaining a liquid crystal element that highly combines liquid crystal orientation with low voltage drive, the Mw of polyorganosiloxane (PS) is preferably 100,000 or less, more preferably 50,000 or less, and further preferably 10,000 or less.

[0120] In addition, when the polyorganosiloxane (PS) has either a cage structure or an incomplete cage structure, the molecular weight distribution (Mw / Mn), represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), of the polyorganosiloxane (PS) is preferably 3.0 or less, more preferably 2.8 or less, and even more preferably 2.5 or less. In this specification, Mw and Mn of the polyorganosiloxane are polystyrene-equivalent values measured by gel permeation chromatography (GPC).

[0121] When the polyorganosiloxane (PS) is a cyclic polysiloxane, the molecular weight of the polyorganosiloxane (PS) is preferably 300 or more, more preferably 400 or more, and even more preferably 500 or more. When the polyorganosiloxane (PS) is a cyclic polysiloxane, the molecular weight is preferably 1400 or less, more preferably 1350 or less.

[0122] In the liquid crystal alignment agent of the present disclosure, the content of polyorganosiloxane (PS) is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, relative to 100 parts by mass of the solid content (components other than the solvent of the liquid crystal alignment agent) contained in the liquid crystal alignment agent. By setting the content of polyorganosiloxane (PS) within the above range, a liquid crystal element capable of achieving highly low-voltage drive while maintaining good liquid crystal alignment can be obtained.

[0123] <Other ingredients>

[0124] The liquid crystal aligning agent of the present disclosure may also contain a component different from the polyorganosiloxane (PS) (hereinafter also referred to as "other components"). Examples of other components include polymers having a main skeleton different from that of the polyorganosiloxane (PS) (hereinafter also referred to as "other polymers"), crosslinking agents, adhesion promoters, solvents, and the like.

[0125] Other polymers

[0126] The main skeleton of other polymers is not particularly limited. As other polymers, for example, polyamic acid, polyamic acid ester, polyimide, polyester, polyenamine (polyenamine), polyurea, polyamide, polyamide-imide, polybenzoxazole precursor, polybenzoxazole, cellulose derivatives, polyacetal, addition polymers, etc. As addition polymers, for example, (meth) acrylic acid polymers, styrene polymers, maleimide polymers, (meth) acrylic acid-styrene copolymers, (meth) acrylic acid-maleimide copolymers, (meth) acrylic acid-styrene-maleimide copolymers and styrene-maleimide copolymers, etc. can be listed.

[0127] From the perspective of achieving a liquid crystal element that achieves low-voltage drive, minimizes residual images, and achieves high reliability, the other polymer is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, and addition polymers. From the perspective of facilitating the partial distribution of the polyorganosiloxane (PS) in the upper layer, significantly enhancing the liquid crystal alignment and the effect of improving low-voltage driveability, and facilitating adjustment of electrical properties, the other polymer is particularly preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

[0128] When the liquid crystal aligning agent contains other polymers, the content ratio of the other polymer is preferably 1 part by mass or more, more preferably 2 parts by mass or more, relative to 100 parts by mass of the total amount of the polyorganosiloxane (PS) and other polymers. In addition, the content ratio of the other polymer is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, relative to 100 parts by mass of the total amount of the polyorganosiloxane (PS) and other polymers.

[0129] Cross-linking agent

[0130] The liquid crystal alignment agent disclosed herein preferably contains a crosslinking agent. By further containing a crosslinking agent, a liquid crystal element that achieves low voltage driving and has less residual image can be obtained. Examples of the crosslinking agent include compounds having two or more selected from the group consisting of an oxetane group, an oxetanyl group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a carboxyl group, a protected carboxyl group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, a protected isocyanate group, and a polymerizable carbon-carbon unsaturated bond group (excluding polyorganosiloxane (PS)).

[0131] From the perspective of obtaining a liquid crystal alignment film that exhibits good weak anchoring properties and sufficiently suppresses residual images, the number of crosslinkable groups contained in one molecule of the crosslinking agent is preferably 2 to 10, more preferably 2 to 6. Furthermore, the molecular weight of the crosslinking agent is preferably 100 to 1,000, more preferably 100 to 800, and even more preferably 100 to 700.

[0132] Specific examples of crosslinking agents include compounds having an oxetane group or an oxetanyl group, such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, triglycidyl isocyanurate, glycerol polyglycidyl ether, pentaerythritol tetraglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, N,N,N',N'-tetraglycidyl glycoluril, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromo Neopentyl 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, epoxidation reaction products of 2,2'-diallylbisphenol A diallyl ether using hydrogen peroxide, etc.

[0133] Examples of the compound having a cyclic carbonate group include compounds represented by the following formula (d1-1) and formula (d1-2).

[0134] 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 can be preferably used. Specific examples thereof include compounds represented by the following formulas (d2-1) to (d2-5) and (d3-1) to (d3-5), respectively.

[0135] Examples of the compound having a carboxyl group or a protected carboxyl group include maleic acid, itaconic acid, trimellitic acid, tetracarboxylic acid, cis-1,2,3,4-tetrahydrophthalic acid, ethylene glycol bistrimellitic acid, propylene glycol bistrimellitic acid, 4,4′-oxydiphthalic acid, and protected forms thereof.

[0136] Examples of the compound having a mercapto group or a protected mercapto group include 1,2-ethanedithiol, 1,3-propanedithiol, 1,3,4-thiadiazole-2,5-dithiol, 1,10-decanedithiol, pentaerythritol tetrakis(3-mercaptobutyrate), and 1,3,5-tris(2-(3-mercaptobutyryloxy)ethyl)-1,3,5-triazacyclohexane-2,4,6-trione.

[0137] 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), and the like.

[0138] Examples of the compound having a protected isocyanate group include compounds in which the isocyanate group in tolylene diisocyanate, xylene diisocyanate, chlorophenyl diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, or diphenylmethane diisocyanate is protected by 3,6-dimethylpyrazole, methyl ethyl ketoxime, diethyl malonate, or ε-caprolactam; and compounds represented by the following formula (d5-1).

[0139] Examples of compounds having a polymerizable carbon-carbon unsaturated bond group include compounds 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, and compounds represented by the following formulas (d6-1) to (d6-7), respectively.

[0140] [Chemistry 6]

[0141]

[0142] [Chemistry 7]

[0143]

[0144] (In formula (d2-4), Ac is an acetyl group)

[0145] [Chemistry 8]

[0146]

[0147] [Chemistry 9]

[0148]

[0149] [Chemistry 10]

[0150]

[0151] [Chemistry 11]

[0152]

[0153] In terms of obtaining a liquid crystal element that can achieve low-voltage driving while maintaining good liquid crystal orientation and sufficiently reduce residual images, the cross-linking agent is preferably a compound having two or more cross-linking groups selected from the group consisting of oxacyclopropyl, oxetane, cyclic carbonate, hydroxyalkylamide, protected hydroxyalkylamide, amino, protected amino and protected isocyanate groups in one molecule, and more preferably a compound having two or more cross-linking groups selected from the group consisting of oxacyclopropyl, oxetane, cyclic carbonate, hydroxyalkylamide and protected hydroxyalkylamide groups in one molecule.

[0154] As a cross-linking agent, a compound without an aromatic ring (hereinafter also referred to as an "aliphatic cross-linking agent") can be preferably used in order to achieve a liquid crystal element with a better liquid crystal orientation while fully realizing low-voltage driving of the liquid crystal element. The aliphatic cross-linking agent may be a compound having a chain structure or a cyclic structure. As specific examples of the aliphatic cross-linking agent, compounds without an aromatic ring among the compounds exemplified above can be cited.

[0155] With respect to obtaining a liquid crystal alignment film showing weak anchoring characteristics and improving the mechanical properties and adhesion of the liquid crystal alignment film, and obtaining a liquid crystal element that fully reduces the residual image, the content of the cross-linking agent is preferably 0.5 parts by mass or more relative to the total amount of the polymer component contained in the liquid crystal alignment agent (that is, the total amount of polymer (P) and other polymers) 100 parts by mass. The content of the cross-linking agent is more preferably 1 part by mass or more, and further preferably 2 parts by mass or more. In addition, with respect to the viewpoint of obtaining a liquid crystal element showing good liquid crystal orientation, the content of the cross-linking agent is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 10 parts by mass or less relative to the total amount of the polymer component 100 parts by mass.

[0156] ·Adhesives

[0157] An adhesion promoter is a component that improves the adhesion between the liquid crystal alignment film formed using the liquid crystal alignment agent and the substrate or sealant. As the adhesion promoter, 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, (meth)acryloyl, oxirane, oxetanyl, vinyl, and isocyanate groups.

[0158] Specific examples of the functional silane coupling agent include trimethoxysilylbenzoic acid, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane.

[0159] When the liquid crystal aligning agent of the present disclosure contains an adhesion auxiliary agent, content of the adhesion auxiliary agent is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0160] Solvent

[0161] The liquid crystal aligning agent of the present disclosure is prepared in the form of a liquid composition in which polyorganosiloxane (PS) and optionally used components are preferably dispersed or dissolved in an appropriate solvent.

[0162] As the solvent, an organic solvent can be preferably used. Specific examples thereof include: 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;

[0163] Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether (butyl cellosolve), diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether and other (poly)alkylene glycol monoalkyl ethers;

[0164] Alkyl lactates such as methyl lactate, ethyl lactate, and butyl lactate; alkyl alcohols with linear, branched, or cyclic structures such as methanol, ethanol, propanol, butanol, isopropanol, isobutanol, tert-butanol, octanol, 2-ethylhexanol, and cyclohexanol; alkoxy alcohols such as 3-methoxy-1-butanol; keto alcohols such as diacetone alcohol; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, and 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 and other (poly)alkylene glycol monoalkyl ether acetates; ethers such as diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, tetrahydrofuran and other; ketones such as methyl ethyl ketone, diisobutyl ketone, cyclohexanone, cyclopentanone, 2-heptanone, 3-heptanone and other;

[0165] Diacetates such as propylene glycol diacetate, 1,3-butanediol diacetate, and 1,6-hexanediol diacetate; alkoxycarboxylates such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxyacetate, and 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, and ethyl 2-oxobutyrate; aromatic hydrocarbons such as toluene and xylene; phenols such as phenol and methylphenol, etc.

[0166] Other components contained in the liquid crystal alignment agent of the present disclosure include, in addition to those mentioned above, surfactants, antioxidants, metal chelate compounds, curing accelerators, fillers, dispersants, photosensitizers, etc. The proportions of other components can be appropriately selected according to the compound within the range that does not impair the effects of the present disclosure.

[0167] The solid content concentration of the liquid crystal alignment agent disclosed herein (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) can be appropriately selected in consideration of viscosity, volatility, etc. The solid content concentration of the liquid crystal alignment agent disclosed herein 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 can be fully ensured, and a liquid crystal alignment film showing better liquid crystal orientation can be obtained. In addition, if the solid content concentration is 10% by mass or less, the coating can be set to a moderate thickness, and a liquid crystal alignment film showing good liquid crystal orientation can be easily obtained. Furthermore, the viscosity of the liquid crystal alignment agent becomes moderate, and good coating properties can be ensured.

[0168] Weakly anchored liquid crystal alignment film and its manufacturing method

[0169] The liquid crystal alignment film disclosed herein is a weakly anchored liquid crystal alignment film produced using a liquid crystal alignment agent prepared as described above. The method for producing a weakly anchored liquid crystal alignment film using the liquid crystal alignment agent disclosed herein is not particularly limited and can be produced using the same method as for producing a liquid crystal alignment film using a conventionally known liquid crystal alignment agent. In terms of ease of film formation, a method in which the liquid crystal alignment agent disclosed herein is applied to a substrate and the applied surface is preferably heated is preferred.

[0170] The substrate on which the weakly anchored liquid crystal alignment film is formed is not particularly limited. Examples of the substrate include transparent substrates made of glass such as float glass and soda glass, and plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefin).

[0171] The method for coating the liquid crystal alignment agent on the substrate is not particularly limited. The liquid crystal alignment agent can be coated, for example, by spin coating, printing (for example, offset printing, flexographic printing, etc.), inkjet, slit coating, rod coating, extrusion die, direct gravure coater, chamber doctor coater, offset gravure coater, dip coater, MB coater, etc.

[0172] After applying the liquid crystal alignment agent, it is preferred to perform preheating (pre-baking) for the purpose of preventing the liquid crystal alignment agent from sagging. The pre-baking temperature is preferably 30°C to 200°C, and the pre-baking time is preferably 0.25 minutes to 10 minutes. Afterwards, a calcination (post-baking) process is performed for the purpose of further removing the solvent. The calcination temperature (post-baking temperature) is preferably 80°C to 280°C, more preferably 80°C to 250°C. The post-baking time is preferably 5 minutes to 200 minutes. The thickness of the film formed is preferably 0.001μm to 2.5μm. Through the above operation, a weakly anchored liquid crystal alignment film can be simply manufactured. In addition, the coating film after post-baking can also be subjected to an orientation treatment (for example, a rubbing orientation treatment or a light orientation treatment) as needed to obtain a weakly anchored liquid crystal alignment film.

[0173] Method for manufacturing liquid crystal element

[0174] The liquid crystal element disclosed herein can be produced, for example, by a method including the following steps A and B. The order of steps A and B is not particularly limited, and step B may be performed after step A or after step B. Furthermore, steps A and B may be performed simultaneously.

[0175] Step A: a step of forming a weak anchor liquid crystal alignment film on one of a pair of substrates using a weak anchor film-forming liquid crystal alignment agent

[0176] Step B: forming a strong anchor liquid crystal alignment film on the other substrate of a pair of substrates (i.e., the substrate on which the weak anchor liquid crystal alignment film is not formed)

[0177] Step A is preferably performed based on step 1 shown below, and step B is preferably performed based on steps 1 and 2 shown below. Furthermore, a liquid crystal cell is constructed in step 3 using the substrate having a liquid crystal alignment film formed thereon obtained through steps A and B, thereby obtaining a liquid crystal element. Furthermore, the substrate used in step 1 varies depending on the desired operating mode. Steps 2 and 3 are common to each operating mode.

[0178] <Step 1: Coating Film Formation>

[0179] In step 1, a liquid crystal aligning agent is applied to each substrate surface and preferably the applied surface is heated to form a coating film on the substrate. As the liquid crystal aligning agent for forming a strong anchor liquid crystal aligning film, a conventionally known liquid crystal aligning agent can be appropriately used.

[0180] About a pair of substrates, for example, in the case of manufacturing an IPS type or FFS type liquid crystal element, an electrode substrate provided with an electrode patterned into a comb-shaped shape and an opposing substrate without an electrode are used. As an electrode, a transparent conductive film can be cited. As a transparent conductive film, a NESA film (a registered trademark of PPG, USA) containing tin oxide (SnO2) and an indium tin oxide (In2O3-SnO2) containing indium tin oxide (Indium Tin Oxide, ITO) film can be used. As a form when a liquid crystal alignment film is formed on an electrode substrate and an opposing substrate, it can be cited: a form (first form) in which a strong anchoring liquid crystal alignment film is formed on the electrode substrate and a weak anchoring liquid crystal alignment film is formed on the opposing substrate; a form (second form) in which a weak anchoring liquid crystal alignment film is formed on the electrode substrate and a strong anchoring liquid crystal alignment film is formed on the opposing substrate. Among these, from the perspective of low voltage driving of the liquid crystal element, the first form is preferred.

[0181] <Step 2: Orientation Treatment>

[0182] In the case of manufacturing an IPS type or FFS type liquid crystal element, it is preferred to implement a process (orientation treatment) for imparting liquid crystal orientation ability to the coating formed on the substrate in process 1. As an orientation treatment, it is preferred to use a friction treatment in which the surface of the coating formed on the substrate is wiped with cotton (cotton) or nylon, or a light orientation treatment in which the coating is irradiated with light to impart liquid crystal orientation ability. In addition, with respect to the viewpoint of obtaining a liquid crystal element showing good liquid crystal orientation, it is preferred to apply a liquid crystal orientation agent for forming a strong anchoring liquid crystal orientation film on one of the electrode substrate and the opposing substrate, and only the coating formed thereby is subjected to orientation treatment. In terms of making mechanical strength or sealing adhesion more excellent, the liquid crystal orientation agent used in the formation of the strong anchoring liquid crystal orientation film preferably contains a cross-linking agent.

[0183] Furthermore, a weakly anchored liquid crystal alignment film formed using the liquid crystal alignment agent of the present disclosure can provide a liquid crystal element exhibiting good liquid crystal alignment properties even without subjecting the coating film used to obtain the weakly anchored liquid crystal alignment film to an alignment treatment such as a rubbing alignment treatment or a photo-alignment treatment. This characteristic can also be utilized to configure the weakly anchored liquid crystal alignment film formed using the liquid crystal alignment agent of the present disclosure as a protective film disposed on a color filter in a liquid crystal element, thereby allowing the weakly anchored liquid crystal alignment film to function as a protective film (specifically, flattening or protecting the color filter from impurities, humidity, etc.).

[0184] <Step 3: Liquid Crystal Cell Construction>

[0185] Then, a substrate having a strongly anchored liquid crystal alignment film and a substrate having a weakly anchored liquid crystal alignment film are used to manufacture a liquid crystal unit in which a liquid crystal layer is arranged between two substrates arranged opposite to each other. When manufacturing a liquid crystal unit, for example, the following methods can be cited: arranging two substrates opposite to each other with a gap between them in a manner that the liquid crystal alignment films face each other, bonding the peripheral portions of the two substrates with a sealing material, injecting a filling liquid crystal into the cell gap surrounded by the substrate surface and the sealing material, and sealing the injection hole; a method using a liquid crystal droplet (One Drop Fill, ODF) method. As a sealing material, for example, an epoxy resin containing a hardener and aluminum oxide balls as a spacer can be used. As liquid crystals constituting the liquid crystal layer, nematic liquid crystals and smectic liquid crystals can be cited, among which nematic liquid crystals are preferred.

[0186] When manufacturing a liquid crystal display element, a polarizing plate is then attached to the outer surface of the liquid crystal cell. Examples of polarizing plates include a plate formed by sandwiching a polarizing film called an "H film" made by stretching and aligning polyvinyl alcohol while allowing it to absorb iodine, with a cellulose acetate protective film, or a plate containing the H film itself.

[0187] The liquid crystal element disclosed herein can be effectively used in a variety of applications. Specifically, it can be used as various display devices or dimming devices, such as watches, portable game consoles, word processors, notebook personal computers, car navigation systems, camcorders, personal digital assistants (PDAs), digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, information displays, head-mounted displays, and smart glasses, as well as retardation films.

[0188] According to the present disclosure described in detail above, the following aspects are provided.

[0189] [Form 1] A liquid crystal element comprising: a pair of substrates including a first substrate and a second substrate; and a liquid crystal layer including liquid crystal molecules.

[0190] A weakly anchored liquid crystal alignment film is formed on one of the first substrate and the second substrate, and a strongly anchored liquid crystal alignment film having stronger anchoring energy than the weakly anchored liquid crystal alignment film is formed on the other substrate, wherein the weakly anchored liquid crystal alignment film is formed of a liquid crystal alignment agent containing polyorganosiloxane.

[0191] [Aspect 2] The liquid crystal element according to [Aspect 1], wherein the slow axes of the liquid crystal molecules are aligned substantially parallel to the substrate surface when the liquid crystal element is not driven.

[0192] [Aspect 3] The liquid crystal element according to [Aspect 1] or [Aspect 2], wherein the strong anchor liquid crystal alignment film is a rubbed alignment film or a photo-alignment film.

[0193] [Aspect 4] The liquid crystal element according to any one of [Aspect 1] to [Aspect 3], wherein the polyorganosiloxane has at least one of a cage structure, an incomplete cage structure, and a cyclic structure.

[0194] [Aspect 5] The liquid crystal element according to any one of [Aspect 1] to [Aspect 4], wherein the polyorganosiloxane does not have a photo-alignment group.

[0195] [Aspect 6] The liquid crystal element according to any one of [Aspect 1] to [Aspect 5], wherein the polyorganosiloxane contains a structural unit represented by the formula (S-1).

[0196] [Aspect 7] The liquid crystal element according to any one of [Aspect 1] to [Aspect 5], wherein the polyorganosiloxane is a cyclic polysiloxane having a molecular weight of 1,500 or less.

[0197] [Aspect 8] The liquid crystal element according to any one of [Aspect 1] to [Aspect 7], wherein the polyorganosiloxane does not have a benzene ring.

[0198] [Form 9] The liquid crystal element according to any one of [Form 1] to [Form 8], wherein the polysiloxane does not have a partial structure in which two or more cyclohexane rings are bonded via a single bond, -COO-, or -NR- (wherein R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms).

[0199] [Aspect 10] The liquid crystal element according to any one of [Aspect 1] to [Aspect 9], wherein the liquid crystal aligning agent further contains a polymer having a main skeleton different from that of the polyorganosiloxane.

[0200] [Aspect 11] The liquid crystal element according to any one of [Aspect 1] to [Aspect 10], wherein the weak anchor liquid crystal alignment film is a film that has not been subjected to an alignment treatment.

[0201] [Aspect 12] A liquid crystal alignment agent for forming a weak anchor film, which is used to form a weak anchor liquid crystal alignment film, wherein the liquid crystal alignment agent for forming a weak anchor film contains polyorganosiloxane.

[0202] [Aspect 13] The liquid crystal aligning agent for forming a weak anchor film according to [Aspect 11], wherein the polyorganosiloxane has at least any one of a cage structure, an incomplete cage structure, and a cyclic structure.

[0203] [Aspect 14] The liquid crystal aligning agent for forming a weak anchor film according to [Aspect 12] or [Aspect 13], wherein the polyorganosiloxane does not have a photo-alignment group.

[0204] [Aspect 15] The liquid crystal aligning agent for forming a weak anchor film according to any one of [Aspect 12] to [Aspect 14], wherein the polyorganosiloxane contains a structural unit represented by the formula (S-1).

[0205] [Aspect 16] The liquid crystal alignment agent for forming a weak anchor film according to any one of [Aspect 12] to [Aspect 15], wherein the polyorganosiloxane is a reaction product of a polymer having a structural unit represented by the formula (S-2) and a carboxylic acid, wherein the carboxylic acid has an alkyl group having 1 to 30 carbon atoms, a "*-R 2 -(OR 3 ) r -OR 4 Any of a group having 2 to 30 carbon atoms represented by " and a monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms and having one aliphatic hydrocarbon ring.

[0206] [Aspect 17] The liquid crystal aligning agent for forming a weak anchor film according to any one of [Aspect 12] to [Aspect 14], wherein the polyorganosiloxane is a cyclic polysiloxane having a molecular weight of 1,500 or less.

[0207] [Aspect 18] The liquid crystal aligning agent for forming a weak anchor film according to any one of [Aspect 12] to [Aspect 17], wherein the polyorganosiloxane does not have a benzene ring.

[0208] [Form 19] A liquid crystal alignment agent for forming a weak anchor film according to any one of [Form 12] to [Form 18], wherein the polysiloxane does not have a partial structure in which two or more cyclohexane rings are bonded by a single bond, -COO- or -NR- (wherein R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms).

[0209] [Aspect 20] The liquid crystal aligning agent for forming a weak anchor film according to any one of [Aspect 12] to [Aspect 19], further comprising a crosslinking agent.

[0210] [Aspect 21] The liquid crystal aligning agent for forming a weak anchor film according to [Aspect 20], wherein the crosslinking agent does not have an aromatic ring.

[0211] [Form 22] A liquid crystal alignment agent for forming a weak anchoring film according to [Form 20] or [Form 21], wherein the crosslinking agent has at least one of two or more selected from the group consisting of an oxetane group, an oxetane group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a carboxyl group, a protected carboxyl group, a mercapto group, a protected mercapto group, an amino group, a protected amino group, a protected isocyanate group and a polymerizable carbon-carbon unsaturated bond group in one molecule.

[0212] [Aspect 23] The liquid crystal aligning agent for forming a weak anchor film according to any one of [Aspect 12] to [Aspect 22], further comprising a polymer whose main skeleton is different from that of the polyorganosiloxane.

[0213] [Form 24] A method for manufacturing a liquid crystal element, comprising: a process of forming a weakly anchored liquid crystal orientation film on one of a pair of substrates using a liquid crystal orientation agent for forming a weakly anchored film according to any one of [Forms 12] to [Form 23]; and a process of forming a strongly anchored liquid crystal orientation film having an anchoring energy stronger than that of the weakly anchored liquid crystal orientation film on the other substrate.

[0214] [Aspect 25] The method for manufacturing a liquid crystal element according to [Aspect 24], wherein the strong anchor liquid crystal alignment film is a rubbed alignment film or a photo-alignment film.

[0215] [Example]

[0216] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples.

[0217] In the following examples, the imidization ratio of the polyimide and the molecular weight (Mw, Mn) of the polymer (polyorganosiloxane) were measured by the following methods.

[0218] <Imidization ratio of polyimide>

[0219] The polyimide solution was added to pure water, the obtained precipitate was fully dried under reduced pressure at room temperature, and then dissolved in deuterated dimethyl sulfoxide. The H NMR spectra were performed at room temperature using tetramethylsilane as a reference substance. 1 H-Nuclear Magnetic Resonance, 1 H-NMR) determination. 1 The imidization rate [%] was determined by analyzing the H-NMR spectrum and using the following formula (1).

[0220] Imidization rate [%] = (1-(β 1 / (β 2 ×α)))×100···(1)

[0221] (In formula (1), β 1 is the peak area of the proton origin of the NH group appearing near the chemical shift of 10 ppm, β 2 is the peak area of other proton sources, and α is the ratio of the number of other protons to one proton of the NH group in the polymer precursor (polyamic acid)

[0222] <Molecular weight (Mw, Mn) of polymer (polyorganosiloxane)>

[0223] The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) under the following conditions.

[0224] Device: Showa Denko's "GPC-101"

[0225] GPC columns: Combination of "GPC-KF-801", "GPC-KF-802", "GPC-KF-803" and "GPC-KF-804" manufactured by Shimadzu GLC Co., Ltd.

[0226] Mobile phase: tetrahydrofuran (THF)

[0227] Column temperature: 40°C

[0228] Flow rate: 1.0 mL / min

[0229] Sample concentration: 1.0 mass%

[0230] Sample injection volume: 100 μL

[0231] Detector: Differential refractometer

[0232] Standard material: monodisperse polystyrene

[0233] The following are the abbreviations of the compounds used in the following examples. For ease of description, "compound represented by formula (X)" may be simply referred to as "compound (X)." Unless otherwise specified, "parts" and "%" in the Examples and Comparative Examples are by mass.

[0234] (Siloxane monomer) S-1 to S-4

[0235] [Chemistry 12]

[0236]

[0237] (Cyclic polysiloxane) CS-1, CS-2

[0238] [Chemistry 13]

[0239]

[0240] (Reactive compound (carboxylic acid)) C-1 to C-12

[0241] [Chemistry 14]

[0242]

[0243] (Tetracarboxylic dianhydride) TA-1 to TA-7

[0244] [Chemistry 15]

[0245]

[0246] (Diamine) DA-1~DA-21

[0247] [Chemistry 16]

[0248]

[0249] [Chemistry 17]

[0250]

[0251] (Additives) AD-1~AD-8

[0252] [Chemistry 18]

[0253]

[0254] [Chemistry 19]

[0255]

[0256] <Polymer Synthesis>

[0257] 1. Synthesis of polyorganosiloxanes (polymers (PS-1) to (PS-18), polymers (PCS-1) to (PCS-3))

[0258] [Synthesis example 1-1]

[0259] In a 1000 mL three-necked flask, 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (compound (S-1)) as a siloxane monomer, 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine were placed and mixed at room temperature. Subsequently, 100 g of deionized water was added dropwise from a dropping funnel over a period of 30 minutes, mixed under reflux, and reacted at 80 ° C for 6 hours. After the reaction was completed, the organic layer was taken out and washed with a 0.2% by mass aqueous solution of ammonium nitrate until the washed water became neutral, and then the solvent and water were distilled off under reduced pressure. Methyl isobutyl ketone was added in an appropriate amount to obtain a 50% by mass solution of a polymer (ESSQ-1) as a polyorganosiloxane having an epoxy group.

[0260] In a 500 mL three-necked flask, a compound (C-1) having an epoxy group content of 15 mol %, 1.00 g of tetrabutylammonium bromide, 20.0 g of a solution containing the polymer (ESSQ-1), and 290.0 g of methyl isobutyl ketone were added and stirred at 90°C for 18 hours. After cooling to room temperature, the liquid separation and washing operation was repeated 10 times using distilled water. Thereafter, the organic layer was recovered, and the concentration and dilution with N-methyl-2-pyrrolidone (NMP) were repeated twice using a rotary evaporator. Then, NMP was used to adjust the solid content concentration to 10% by mass to obtain an NMP solution of polyorganosiloxane (set to polymer (PS-1)). By 1 H-NMR determination, 29 The structure of polymer (PS-1) was confirmed using Si-NMR, gel permeation chromatography (GPC), and quadrupole time-of-flight mass spectrometry (QTOF-MS). The results revealed a polyorganosiloxane with a mixture of cage-like structures, incomplete cage-like structures, or a predominantly cage-like structure. The weight-average molecular weight of polymer (PS-1) was 2,100.

[0261] [Synthesis Example 1-2 to Synthesis Example 1-18]

[0262] The same operation as in Synthesis Example 1-1 was performed except that the types and amounts of the siloxane monomer and the carboxylic acid were changed as described in Table 1 to obtain polyorganosiloxanes (these are referred to as polymers (PS-2) to (PS-18)). 1 H-NMR determination, 29 Structural confirmation by Si-NMR, GPC, and QTOF-MS confirmed that all polymers were polyorganosiloxanes containing a mixture of cage and incomplete cage structures, or a predominantly cage structure. The weight-average molecular weight of each polymer is shown in Table 1.

[0263] [Table 1]

[0264]

[0265] [Synthesis Example 1-19]

[0266] A 500 mL three-necked flask was charged with 40.0 g of cyclic polysiloxane (CS-1), 25 mol% of compound (C-1) relative to the amount of epoxy groups in cyclic polysiloxane (CS-1), 4.00 g of tetrabutylammonium bromide, and 290.0 g of propylene glycol methyl ether acetate, and stirred at 100° C. for 8 hours. After cooling to room temperature, the liquid separation and washing operation with distilled water was repeated 10 times. The organic layer was then recovered, concentrated using a rotary evaporator and diluted with NMP twice, and then adjusted with NMP to a solid content concentration of 10% by mass to obtain an NMP solution of polyorganosiloxane (hereinafter referred to as polymer (PCS-1)). The weight average molecular weight of polymer (PCS-1) was 900.

[0267] [Synthesis Example 1-20, Synthesis Example 1-21]

[0268] Polyorganosiloxanes (referred to as polymer (PCS-2) and polymer (PCS-3)) were obtained by the same operation as in Synthesis Example 1-19 except that the types and amounts of cyclic polysiloxane and carboxylic acid were changed as described in Table 2. The weight average molecular weight of each polymer is shown in Table 2.

[0269] [Table 2]

[0270]

[0271] 2. Synthesis of polyamic acid

[0272] [Synthesis example 2-1]

[0273] 100 parts by mole of a tetracarboxylic dianhydride compound (TA-1) and 100 parts by mole of a diamine compound (DA-1) were dissolved in N-methyl-2-pyrrolidone (NMP), and the mixture was reacted at 60° C. for 6 hours to obtain a solution containing 20% by mass of a polyamic acid (referred to as polymer (PI-1)).

[0274] [Synthesis Example 2-2 to Synthesis Example 2-9, Synthesis Example 2-11 to Synthesis Example 2-15]

[0275] The same operation as in Synthesis Example 2-1 was performed, except that the types and amounts of the tetracarboxylic dianhydride and diamine compounds used were changed as described in Table 3, to obtain polyamic acids (polymers (PI-2) to (PI-9), and polymers (PI-11) to (PI-15)). In Table 3, the numerical values for tetracarboxylic dianhydrides (acid dianhydride 1 and acid dianhydride 2) represent the ratio (molar ratio) of each compound relative to 100 parts by mole of the total amount of tetracarboxylic dianhydride used in the synthesis of the polymer. The numerical values for diamine compounds (diamine 1 to diamine 4) represent the ratio (molar ratio) of each compound relative to 100 parts by mole of the total amount of diamine compounds used in the synthesis of the polymer.

[0276] 3. Synthesis of polyimide

[0277] [Synthesis example 2-10]

[0278] 100 parts by mole of the tetracarboxylic dianhydride compound (TA-4), and 30 parts by mole of the diamine compound (DA-5), 40 parts by mole of the compound (DA-8), and 30 parts by mole of the compound (DA-9) 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-closure reaction was carried out at 80°C for 4 hours. After the dehydration ring-closure reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by mass of a polyimide (referred to as polymer (PI-10)) with an imidization rate of approximately 60%.

[0279] [Table 3]

[0280]

[0281] <Preparation of Liquid Crystal Alignment Agent>

[0282] (1) Preparation of liquid crystal alignment agent for weak anchor film formation

[0283] [Preparation Example 1]

[0284] A solution containing 50 parts by mass of the polymer (PS-1) obtained in Synthesis Example 1-1 and a solution containing 50 parts by mass of the polymer (PI-1) obtained in Synthesis Example 2-1 were mixed. 5 parts by mass of the compound (AD-8) were added to the mixture, and the mixture was diluted with N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), butyl cellosolve (BC), diacetone alcohol (DAA), and diethylene glycol diethylether (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 alignment agent (AL-1) for forming a weak anchor film.

[0285] [Preparation Examples 2 to 21, Preparation Examples 28 to 30]

[0286] Except for changing the types and amounts of polymers and additives as shown in Table 4, the liquid crystal alignment agent for weak anchor film formation (AL-2) to the liquid crystal alignment agent for weak anchor film formation (AL-21) and the liquid crystal alignment agent for weak anchor film formation (AL-28) to the liquid crystal alignment agent for weak anchor film formation (AL-30) were prepared in the same manner as in Preparation Example 1.

[0287] (2) Preparation of liquid crystal alignment agent for forming strong anchor film

[0288] [Preparation Example 22 to Preparation Example 27]

[0289] Except having changed the kind and amount of the polymer and additive as shown in Table 4, it carried out similarly to Preparation Example 1 and prepared the liquid crystal aligning agent (AL-22) for forming a strong anchor film - the liquid crystal aligning agent (AL-27) for forming a strong anchor film.

[0290]

[0291] <Manufacturing and Evaluation of Liquid Crystal Devices (FFS-Type Liquid Crystal Display Devices)>

[0292] FFS liquid crystal cells were manufactured and various characteristics were evaluated. To manufacture an FFS liquid crystal cell, a substrate (electrode substrate) was prepared. On one side of a glass substrate, an electrode pair consisting of a bottom electrode without a pattern, an insulating layer formed of a silicon nitride film, and a top electrode patterned in a comb-like shape were formed in this order. A counter glass substrate (counter substrate) was also prepared.

[0293] A schematic plan view of the top electrode 20 used is shown in FIG. Figure 2 (a) Figure 2 (b). In addition, Figure 2 (a) is a top view of the top electrode 20, Figure 2 (b) is Figure 2 This is an enlarged view of the portion C1 surrounded by the dotted line in (a). In this embodiment, the electrode line width d1 is set to 4 μm, and the distance d2 between the electrodes is set to 6 μm. In addition, as the top electrode 20, four drive electrodes (electrode A, electrode B, electrode C and electrode D) are used. Figure 3 ) In addition, the bottom electrode functions as a common electrode acting on all four systems of driving electrodes, and the regions of the four systems of driving electrodes each become a pixel region.

[0294] [Example 1: Rubbed Alignment FFS Type Liquid Crystal Display Element]

[0295] 1. Manufacturing of liquid crystal display elements

[0296] (1) Formation of weakly anchored liquid crystal alignment film

[0297] A liquid crystal alignment agent (AL-1) for weak anchor film formation was applied to one of the opposing substrates using a spin coater, heated on an 80°C hot plate for 1 minute, and then heated in a 230°C oven with nitrogen purged inside for 30 minutes to form a weak anchor liquid crystal alignment film with an average film thickness of 100 nm.

[0298] (2) Formation of a strongly anchored liquid crystal alignment film based on the rubbing alignment method

[0299] A liquid crystal alignment agent (AL-26) for forming a strong anchor film was applied to the electrode forming surface of the electrode substrate using a spin coater. After heating on a hot plate at 80°C for 1 minute, it was heated in a 230°C oven with nitrogen purged inside for 30 minutes to form a coating with an average film thickness of 100 nm. The coating surface was rubbed twice using a friction machine having a roller wound with a rayon cloth at a roller speed of 1,000 rpm, a stage moving speed of 30 mm / s, and a hair press length of 0.3 mm. At this time, the rubbing direction was aligned with the direction of the rubbing. Figure 2 The rubbing direction was set to be perpendicular to the direction of the double-headed arrow in (b). The rubbed coating film was ultrasonically cleaned in ultrapure water for 1 minute and then dried in an oven at 100° C. for 10 minutes to form a strong anchor liquid crystal alignment film.

[0300] (3) Fabrication of rubbing-aligned FFS liquid crystal cells

[0301] A liquid crystal injection port is left on the periphery of the surface with the liquid crystal alignment film of one of the substrates prepared in (1) and (2), and an epoxy resin adhesive containing aluminum oxide balls with a diameter of 3.5 μm is applied using a dispenser. After that, the surfaces with the liquid crystal alignment films of a pair of substrates are made to face each other and pressed together, and the adhesive is thermally cured at 150°C for 1 hour. Subsequently, a positive liquid crystal (MLC-7028-100 manufactured by Merck) is filled into the gap between the substrates from the liquid crystal injection port, and the liquid crystal injection port is sealed with an epoxy adhesive. Furthermore, in order to remove the flow orientation during liquid crystal injection, the substrate is heated at 120°C and then slowly cooled to room temperature.

[0302] 2. Evaluation

[0303] (1) Evaluation of liquid crystal orientation

[0304] The FFS liquid crystal cell manufactured in 1. (3) was evaluated for its liquid crystal orientation by observing the presence of abnormal domains using a microscope (50x magnification) based on the changes in brightness when the voltage was turned on / off (applied / released). No abnormal domains were observed, and the result was rated "good (○)"; any abnormal domains were rated "unacceptable (×)." The results were judged to be "good (○)" in the examples described above.

[0305] (2) Evaluation of low-voltage drive

[0306] The FFS type liquid crystal unit manufactured in 1. (3) is sandwiched between two polarizing plates in such a way that the brightness is minimized, and a liquid crystal unit (liquid crystal display element) with a polarizing plate is set between a backlight and a luminance meter arranged in such a way that the optical axes are aligned. Thereafter, a voltage is applied to the liquid crystal display element at intervals of 0.1V until it reaches 10V. By measuring the brightness relative to the applied voltage, a VT curve is obtained, and the voltage value at which the brightness is maximized is estimated. Regarding the evaluation, for the opposing substrate, similarly to the electrode substrate, a liquid crystal display element in which a liquid crystal alignment film is formed by a rubbing alignment method using a liquid crystal alignment agent (AL-26) for forming a strong anchor film is prepared as a reference cell. The maximum brightness voltage of the liquid crystal display element manufactured in each example is judged by how low the voltage is relative to the maximum brightness voltage of the reference cell. A case where the maximum brightness voltage of the liquid crystal display element was lowered by 0.8V or more relative to the maximum brightness voltage of the reference cell was rated as "good (○)", a case where the maximum brightness voltage of the liquid crystal display element was lowered by 0.4V or more but less than 0.8V relative to the reference cell was rated as "acceptable (△)", and a case where the maximum brightness voltage of the liquid crystal display element relative to the reference cell was lowered by less than 0.4V was rated as "poor (×)". The result was "acceptable (△)" in this example.

[0307] (3) Evaluation of alternating current (AC) afterimage characteristics

[0308] For the FFS type liquid crystal unit manufactured in 1. (3), a birefringence meter (manufactured by AXOMETRICS, AXOSTEP high-precision Mueller Matrix Imaging Polarimeter) was used to apply an AC voltage that gave the maximum brightness, and the change in the liquid crystal azimuth angle before and after driving for 2 days was measured. Regarding the evaluation, a change in the liquid crystal azimuth angle of less than 0.5 degrees was set as "good (○)", a change of 0.5 degrees or more and less than 1 degree was set as "acceptable (△)", and a change of 1 degree or more was set as "poor (×)". The smaller the change in the liquid crystal azimuth angle, the less likely it is to produce an AC afterimage when the liquid crystal display element is driven for a long time, and it can be said that the liquid crystal orientation is better. As a result, the evaluation was "acceptable (△)" in this embodiment.

[0309] (4) Evaluation of sealing material adhesion

[0310] A liquid crystal alignment agent (AL-1) for forming a weak anchor film and a liquid crystal alignment agent (AL-26) for forming a strong anchor film were applied to glass substrates respectively using a spin coater, heated on a hot plate at 80°C for 1 minute, and then heated in a 230°C oven in which the interior of the chamber was substituted with nitrogen for 30 minutes to produce two glass substrates each having a coating film with an average film thickness of 100 nm. Next, an ODF sealant (S-WB42 manufactured by Sekisui Chemical Co., Ltd.) was applied to the center portion of the surface with the coating film of one glass substrate, and the other glass substrate was bonded together in such a manner that the coating film of the other glass substrate was in contact with the ODF sealant. The amount of ODF sealant applied was set so that the diameter of the ODF sealant after the substrates were bonded became 3 mm. Afterwards, a metal halide lamp was used to irradiate at 30,000 J / m 2 After being exposed to light (converted to 365nm), the film was heated in an oven at 120℃ for 1 hour to obtain an evaluation unit. After that, a small desktop tester (model: EZ-LX) from Shimadzu Corporation was used to press the evaluation unit and measure the pressure (N) when the film peeled off (mainly due to the interface damage between the ODF sealant and the film or the cohesive damage inside the ODF sealant). The pressure (N) at the time of peeling was divided by the area (mm2) of the ODF sealant. 2 ) to calculate the film's adhesion to the ODF sealant and substrate (N / mm 2 ). For evaluation, the pressure was measured at 1.5 N / mm 2 The above cases were rated as "good (○)", and 1.0 N / mm 2 More than but less than 1.5N / mm2 If the value is less than 1.0N / mm, set it as "OK (△)". 2 The case of was evaluated as "poor (×)". The result was evaluated as "good (○)" in this example.

[0311] (5) Evaluation of liquid crystal response speed

[0312] The liquid crystal cell manufactured in step 1.(3) was sandwiched between two polarizing plates arranged in a crossed Nicol configuration and then connected to a function generator. The liquid crystal cell connected to the function generator was placed on a backlight. First, the brightness of light transmitted through the liquid crystal cell was measured using a photo multimeter without applying a voltage, and the value was set as a relative transmittance of 0%. Next, a rectangular wave with a positive and negative amplitude equal to the maximum brightness voltage obtained in step 2.(2) of the low-voltage drive evaluation was applied between the electrodes of the liquid crystal cell for 1 second using the function generator. The transmittance at this time was measured in the same manner as described above, and the value was set as a relative transmittance of 100%. Furthermore, while a rectangular wave with a positive and negative amplitude equal to the maximum brightness voltage obtained in step 2.(2) of the low-voltage drive evaluation was applied to each liquid crystal cell using the function generator, the time it took for the relative transmittance to transition from 10% to 90% was measured. This time was defined as the response speed of the liquid crystal in the ON state (when voltage was applied). Furthermore, when the rectangular wave application was stopped and the 0V state was switched, the time it took for the relative transmittance to transition from 90% to 10% was measured. This time was defined as the response speed in the OFF state (when voltage application was released). For the ON state response speed and the OFF state response speed, a response speed of less than 50ms was rated "good (○)", a response speed of 50ms or more but less than 70ms was rated "acceptable (△)", and a response speed of 70ms or more was rated "poor (×)". As a result, in the example described above, the ON state response speed and the OFF state response speed were both judged to be "good (○)".

[0313] [Examples 2 to 18, Example 32]

[0314] A rubbed FFS liquid crystal display element was produced and various evaluations were performed in the same manner as in Example 1, except that the types of the liquid crystal aligning agents used (weak anchor film-forming liquid crystal aligning agent and strong anchor film-forming liquid crystal aligning agent) were changed as described in Table 5. The evaluation results are shown in Table 5.

[0315] [Comparative Example 1]

[0316] An FFS liquid crystal display device was produced and various evaluations were performed in the same manner as in Example 1, except that the type of liquid crystal aligning agent used was changed and the coating film formed on the opposing substrates was also subjected to rubbing treatment as described in Table 5. Furthermore, when the pair of substrates were stacked, the rubbing directions of the substrates were set to be antiparallel. The evaluation results are shown in Table 5.

[0317] [Comparative Example 2]

[0318] An FFS liquid crystal display device was produced and various evaluations were performed in the same manner as in Example 1, except that the type of liquid crystal aligning agent used was changed as described in Table 5. Furthermore, the coating film formed on the opposing substrate was not subjected to a rubbing treatment as in Example 1. The evaluation results are shown in Table 5.

[0319] [Example 19: Photo-aligned FFS-type liquid crystal display element]

[0320] 1. Manufacturing of liquid crystal display elements

[0321] (1) Formation of weakly anchored liquid crystal alignment film

[0322] A liquid crystal alignment agent (AL-1) for weak anchor film formation was applied to one of the opposing substrates using a spin coater, heated on an 80°C hot plate for 1 minute, and then heated in a 230°C oven with nitrogen purged inside for 30 minutes to form a weak anchor liquid crystal alignment film with an average film thickness of 100 nm.

[0323] (2) Formation of a strongly anchored liquid crystal alignment film based on the photo-alignment method

[0324] A liquid crystal alignment agent (AL-22) for forming a strong anchor film was applied to the electrode forming surface of the electrode substrate using a spin coater. The film was then heated on an 80°C hot plate for 1 minute, and then heated in a 230°C oven with nitrogen purged inside for 30 minutes to form a coating with an average film thickness of 100 nm. The coating surface was irradiated with 200 mJ / cm2 of linearly polarized 254 nm bright light using a Hg-Xe lamp from the normal direction of the substrate. 2 At this time, the direction of the line segment projected onto the substrate by the polarization plane of the polarized ultraviolet ray is the same as that of the line segment projected onto the substrate. Figure 2 The polarization plane direction was set to be parallel to the direction of the double-headed arrow in (b). The coating film subjected to the photo-alignment treatment was heated for 30 minutes in a 230° C. oven purged with nitrogen to form a strong anchor liquid crystal alignment film.

[0325] (3) Fabrication of photo-aligned FFS liquid crystal cells

[0326] An FFS type liquid crystal display element was manufactured in the same manner as in Example 1 using the pair of substrates produced in (1) and (2).

[0327] 2. Evaluation

[0328] The liquid crystal orientation, low-voltage drive capability, AC image retention characteristics, and liquid crystal response speed were evaluated in the same manner as in Example 1, except that the photo-aligned FFS liquid crystal cell produced in 1.(3) was used. Furthermore, sealant adhesion was evaluated using the same method as in Example 1. The evaluation results are shown in Table 5.

[0329] [Example 20 to Example 31]

[0330] A photo-aligned FFS liquid crystal display element was produced and various evaluations were performed in the same manner as in Example 19, except that the types of the liquid crystal aligning agents used (weak anchor film-forming liquid crystal aligning agent and strong anchor film-forming liquid crystal aligning agent) were changed as described in Table 5. The evaluation results are shown in Table 5.

[0331] [Comparative Example 3]

[0332] A photo-aligned FFS liquid crystal display element was produced and various evaluations were performed in the same manner as in Example 19, except that the type of liquid crystal alignment agent used was changed and the coating film formed on the opposing substrate was also subjected to photo-alignment treatment as described in Table 5. Furthermore, when the pair of substrates were stacked, the projection directions of the polarization axes of the substrates on the substrate surfaces during light irradiation were arranged to be antiparallel. The evaluation results are shown in Table 5.

[0333] [Comparative Example 4]

[0334] A photo-aligned FFS liquid crystal display element was produced and various evaluations were performed in the same manner as in Example 19, except that the type of liquid crystal aligning agent used was changed as described in Table 5. Furthermore, the coating film formed on the opposing substrate was not subjected to photo-alignment treatment as in Example 19. The evaluation results are shown in Table 5.

[0335] [Table 5]

[0336]

[0337] <Manufacturing and Evaluation of Liquid Crystal Display Elements (TN-Type Liquid Crystal Display Elements)>

[0338] [Example 33]

[0339] 1. Manufacturing of liquid crystal display elements

[0340] A liquid crystal alignment agent (AL-9) for forming a weak anchor film was applied using a spin coater onto the electrode-forming surface of one of a pair of (two) glass substrates with transparent electrodes comprising an ITO film. The substrate was then heated on an 80°C hot plate for 1 minute. Subsequently, the substrate was heated in a 230°C oven, the atmosphere of which had been purged with nitrogen, for 30 minutes to form a weak anchor liquid crystal alignment film having an average thickness of 100 nm.

[0341] In addition, a liquid crystal alignment agent (AL-27) for forming a strong anchor film was applied to the electrode forming surface of the other substrate in a pair of glass substrates using a spin coater and heated on a hot plate at 80°C for 1 minute. Afterwards, the film was heated for 30 minutes in an oven at 230°C in which nitrogen was replaced in the reservoir to form a coating with an average film thickness of 100 nm. The coating was rubbed using a friction machine having a roller wound with rayon cloth at a roller speed of 400 rpm, a stage moving speed of 30 cm / second, and a hair press length of 0.4 mm. Afterwards, ultrasonic cleaning was performed in ultrapure water for 1 minute, and then dried in a clean oven at 100°C for 10 minutes to obtain a substrate with a strong anchor liquid crystal alignment film.

[0342] An epoxy resin adhesive containing 3.5 μm diameter alumina balls was applied to the periphery of the surface of one of the substrates having the liquid crystal alignment film by screen printing. The liquid crystal alignment film surfaces of the two substrates were then placed facing each other, overlapped, and pressure-bonded. The adhesive was then heated at 150°C for one hour to thermally cure. Subsequently, a positive liquid crystal (MLC-2055, manufactured by Merck) was filled into the gap between the substrates through the liquid crystal injection port. The liquid crystal injection port was then sealed with an epoxy adhesive. Furthermore, to remove the flow alignment caused by the liquid crystal injection, the process was heated at 150°C for 10 minutes and then slowly cooled to room temperature.

[0343] 2. Evaluation

[0344] Except for using the rubbed TN liquid crystal cell produced in 1. above, various evaluations of liquid crystal orientation, low voltage driveability, AC afterimage characteristics, sealant adhesion, and liquid crystal response speed were performed in the same manner as in Example 1. The evaluation results are shown in Table 6.

[0345] [Example 34]

[0346] A rubbed TN liquid crystal display device was produced and various evaluations were performed in the same manner as in Example 33, except that the types of the liquid crystal aligning agents used (liquid crystal aligning agent for weak anchor film formation and liquid crystal aligning agent for strong anchor film formation) were changed as described in Table 6. The evaluation results are shown in Table 6.

[0347] [Comparative Example 5]

[0348] A TN-type liquid crystal display device was produced and various evaluations were performed in the same manner as in Example 33, except that the type of liquid crystal aligning agent used was changed and the coating film formed on the opposing substrate was also subjected to rubbing treatment as described in Table 6. Furthermore, when the pair of substrates were stacked, the rubbing directions of the substrates were orthogonal to each other. The evaluation results are shown in Table 6.

[0349] [Table 6]

[0350]

[0351] As shown in Tables 5 and 6, in Examples 1 to 34, any of the liquid crystal orientation, low voltage driveability, AC afterimage characteristics, sealant adhesion, and liquid crystal response speed were evaluated as good or acceptable, achieving a balance between various characteristics.

[0352] When Example 2 in which other polymers were further added was compared with Example 16 in which no other polymers were added, the addition of other polymers improved low-voltage drive and AC residual image characteristics. In addition, compared with the example (Example 1) in which a cross-linking agent having an aromatic ring was used, in the example in which an aliphatic cross-linking agent was used, a tendency was seen to further effectively achieve low-voltage drive of the liquid crystal element and reduce AC residual images. Furthermore, in the example in which compounds (C-1) to (C-8) or (C-10) were used as carboxylic acids introduced into the side chains of polyorganosiloxanes, a balance of various characteristics was further achieved.

[0353] In contrast, the low-voltage drive performance was evaluated as "poor" in Comparative Examples 1, 3, and 5. Furthermore, in Comparative Example 2, even after heating the manufactured liquid crystal cell at 120°C and slowly cooling it to room temperature, flow alignment and bright spots due to poor alignment were partially observed, resulting in a "poor" evaluation for liquid crystal orientation. Furthermore, since the liquid crystal orientation was evaluated as "poor" in Comparative Example 2, no other evaluations were performed. In Comparative Example 4, the AC afterimage characteristics were evaluated as "poor."

Claims

1. A liquid crystal element comprising: a pair of substrates, comprising a first substrate and a second substrate; as well as a liquid crystal layer comprising liquid crystal molecules, A weak anchor liquid crystal alignment film is formed on one of the first substrate and the second substrate, and a strong anchor liquid crystal alignment film having stronger anchoring energy than the weak anchor liquid crystal alignment film is formed on the other substrate. The weak anchor liquid crystal alignment film is formed of a liquid crystal alignment agent containing polyorganosiloxane.

2. The liquid crystal element according to claim 1, wherein When the liquid crystal element is not driven, the slow axes of the liquid crystal molecules are aligned parallel to the substrate surface.

3. The liquid crystal element according to claim 1, wherein The strong anchoring liquid crystal alignment film is a rubbing alignment film or a photo-alignment film.

4. The liquid crystal element according to claim 1, wherein The polyorganosiloxane has at least one of a cage structure, an incomplete cage structure, and a cyclic structure.

5. The liquid crystal element according to claim 1, wherein The polyorganosiloxane does not have a photo-alignment group. The liquid crystal element according to claim 1 , wherein The polyorganosiloxane comprises a structural unit represented by the following formula (S-1); In formula (S-1), R 1 is an alkyl group with 1 to 30 carbon atoms, "*-R 2 -(OR 3 ) r -OR 4 " is a monovalent group bonded to a silicon atom via a single bond or a divalent linking group, wherein R 2 and R 3 are independently alkanediyl; r is an integer greater than 0; when r is 0, R 4 is an alkyl group, and when r is 1 or more, R 4 is a hydrogen atom or an alkyl group.

7. The liquid crystal element according to claim 1, wherein The polyorganosiloxane is a cyclic polysiloxane having a molecular weight of 1,500 or less.

8. The liquid crystal element according to claim 1, wherein The polyorganosiloxane does not have a benzene ring.

9. The liquid crystal element according to claim 1, wherein The polyorganosiloxane does not have a partial structure in which two or more cyclohexane rings are bonded via a single bond, -COO-, or -NR-, wherein R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

10. The liquid crystal element according to claim 1, wherein The liquid crystal alignment agent further includes a polymer having a main skeleton different from that of the polyorganosiloxane.

11. The liquid crystal element according to claim 1, wherein The weak anchor liquid crystal alignment film is a film that has not been subjected to an alignment treatment.

12. A liquid crystal alignment agent for forming a weak anchor film, for forming a weak anchor liquid crystal alignment film, wherein the liquid crystal alignment agent for forming a weak anchor film contains polyorganosiloxane. 13 . The liquid crystal alignment agent for forming a weak anchor film according to claim 12 , wherein The polyorganosiloxane has at least one of a cage structure, an incomplete cage structure, and a cyclic structure.

14. The liquid crystal alignment agent for forming a weak anchor film according to claim 12, wherein The polyorganosiloxane does not have a photo-alignment group. 15 . The liquid crystal alignment agent for forming a weak anchor film according to claim 12 , wherein The polyorganosiloxane comprises a structural unit represented by the following formula (S-1); In formula (S-1), R 1 is an alkyl group with 1 to 30 carbon atoms, "*-R 2 -(OR 3 ) r -OR 4 " is a monovalent group bonded to a silicon atom via a single bond or a divalent linking group, wherein R 2 and R 3 are independently alkanediyl; r is an integer greater than 0; when r is 0, R 4 is an alkyl group, and when r is 1 or more, R 4 is a hydrogen atom or an alkyl group.

16. The liquid crystal alignment agent for forming a weak anchor film according to claim 12, wherein The polyorganosiloxane is a reaction product of a polymer having a structural unit represented by the following formula (S-2) and a carboxylic acid, wherein the carboxylic acid has an alkyl group having 1 to 30 carbon atoms, "*-R 2 -(OR 3 ) r -OR 4 "Any of a group having 2 to 30 carbon atoms and a monovalent alicyclic hydrocarbon group having 1 aliphatic hydrocarbon ring and having 3 to 30 carbon atoms, wherein R 2 and R 3 are independently an alkanediyl group, r is an integer greater than or equal to 0, and when r is 0, R 4 is an alkyl group, and when r is 1 or more, R 4 is a hydrogen atom or an alkyl group; In formula (S-2), Y 1 It is a monovalent group having an epoxy group.

17. The liquid crystal alignment agent for forming a weak anchor film according to claim 12, wherein The polyorganosiloxane is a cyclic polysiloxane having a molecular weight of 1,500 or less.

18. The liquid crystal alignment agent for forming a weak anchor film according to claim 12, wherein The polyorganosiloxane does not have a benzene ring.

19. The liquid crystal alignment agent for forming a weak anchor film according to claim 12, wherein The polyorganosiloxane does not have a partial structure in which two or more cyclohexane rings are bonded via a single bond, -COO-, or -NR-, wherein R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 20 . The liquid crystal aligning agent for forming a weak anchor film according to claim 12 , further comprising a cross-linking agent.

21. The liquid crystal alignment agent for forming a weak anchor film according to claim 20, wherein The cross-linking agent does not have an aromatic ring.

22. The liquid crystal alignment agent for forming a weak anchor film according to claim 20, wherein The cross-linking agent has two or more groups selected from the group consisting of an oxetane group, an oxetanyl group, a cyclic carbonate group, a hydroxyl group, a protected hydroxyl group, a carboxyl group, a protected carboxyl group, a thiol group, a protected thiol group, an amino group, a protected amino group, a protected isocyanate group, and a polymerizable carbon-carbon unsaturated bond group in one molecule. 23 . The liquid crystal aligning agent for forming a weak anchor film according to claim 12 , further comprising a polymer having a main skeleton different from that of the polyorganosiloxane.

24. A method for manufacturing a liquid crystal element, comprising: a step of forming a weak anchor liquid crystal alignment film on one of a pair of substrates using the weak anchor film-forming liquid crystal alignment agent according to any one of claims 12 to 23; and forming a strong anchor liquid crystal alignment film having stronger anchoring energy than the weak anchor liquid crystal alignment film on another substrate; 25. The method for manufacturing a liquid crystal element according to claim 24, wherein The strong anchoring liquid crystal alignment film is a rubbing alignment film or a photo-alignment film.

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