WO2020039695A1 - 液晶配向剤、液晶配向膜、液晶素子及び液晶素子の製造方法 - Google Patents
液晶配向剤、液晶配向膜、液晶素子及び液晶素子の製造方法 Download PDFInfo
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- WO2020039695A1 WO2020039695A1 PCT/JP2019/022689 JP2019022689W WO2020039695A1 WO 2020039695 A1 WO2020039695 A1 WO 2020039695A1 JP 2019022689 W JP2019022689 W JP 2019022689W WO 2020039695 A1 WO2020039695 A1 WO 2020039695A1
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- 0 CC*(NC)O*(C)*C Chemical compound CC*(NC)O*(C)*C 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K19/00—Liquid crystal materials
- C09K19/52—Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
- C09K19/54—Additives having no specific mesophase characterised by their chemical composition
- C09K19/56—Aligning agents
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/54—Silicon-containing compounds
- C08K5/549—Silicon-containing compounds containing silicon in a ring
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L101/00—Compositions of unspecified macromolecular compounds
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
- C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
- C08L79/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
Definitions
- the present disclosure relates to a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal element, and a method for manufacturing a liquid crystal element.
- the liquid crystal element includes a liquid crystal alignment film having a function of aligning liquid crystal molecules in a liquid crystal layer in a certain direction.
- the liquid crystal alignment film is formed on the substrate by applying a liquid crystal alignment agent formed by dissolving a polymer component in an organic solvent to the surface of the substrate, and preferably heating.
- Patent Document 1 discloses an epoxy compound having a nitrogen atom (for example, N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 1,3-bis (N, N'- Diglycidylaminomethyl) cyclohexane, etc.) in the liquid crystal aligning agent.
- Patent Document 2 discloses that a liquid crystal aligning agent contains a compound containing an imide bond and two or more epoxy groups (eg, monoallyl diglycidyl isocyanuric acid, triglycidyl isocyanuric acid, etc.) together with polyamic acid or polyimide.
- Patent Document 3 discloses that a polyfunctional epoxy compound having two or more 3,4-epoxycyclohexane rings is contained in a liquid crystal aligning agent together with a polyamic acid or a polyimide.
- Liquid crystal elements are used not only for display terminals such as personal computers as in the past, but also for indoor and outdoor, such as liquid crystal televisions and car navigation systems, mobile phones, smartphones, information displays, retardation films, light control films, and the like. It is used in a wide variety of applications regardless of In addition, with the expansion of usage, it is assumed that the liquid crystal element is used in a harsher environment than before. Specifically, the liquid crystal element may be irradiated with a backlight for a long time by continuous driving for a long time, used in a high temperature environment, or exposed to a high heat environment. On the other hand, the demand for higher performance of liquid crystal elements is further increasing, and it is required that the element performance can be maintained even under severe environmental conditions.
- the present disclosure has been made in view of the above circumstances, and has as its main object to provide a liquid crystal dispensing agent capable of obtaining a liquid crystal element having excellent light resistance and heat resistance.
- a liquid crystal device comprising the liquid crystal alignment film of [2].
- [5] a step of applying the liquid crystal alignment agent of the above [1] on each of the conductive films of the pair of substrates having a conductive film to form a coating film;
- liquid crystal alignment agent of the present disclosure a liquid crystal element having excellent light resistance and heat resistance can be obtained by containing the cyclic siloxane compound [A] together with the polymer component.
- the liquid crystal alignment agent of the present disclosure contains a polymer component and an additive component. Further, a cyclic siloxane compound [A] having a crosslinkable group is contained as an additive component.
- a cyclic siloxane compound [A] having a crosslinkable group is contained as an additive component.
- hydrocarbon group includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group.
- chain hydrocarbon group means a linear hydrocarbon group and a branched hydrocarbon group that are composed of only a chain structure without a cyclic structure in the main chain. However, it may be saturated or unsaturated.
- alicyclic hydrocarbon group means a hydrocarbon group containing only an alicyclic hydrocarbon structure as a ring structure and not containing an aromatic ring structure. However, it is not necessary to be constituted only by the structure of the alicyclic hydrocarbon, and a part thereof having a chain structure is also included.
- “Aromatic hydrocarbon group” means a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to include only an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic hydrocarbon structure.
- the polymer component contained in the liquid crystal alignment agent is cross-linked by the cyclic siloxane compound [A].
- the type of the main skeleton of the polymer component is not particularly limited.
- Specific examples of the polymer component include, for example, polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyamide, polyamide imide, polystyrene, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, polymaleimide, A styrene-maleimide copolymer or a polymer having poly (meth) acrylate as a main skeleton is exemplified.
- (meth) acrylate means including acrylate and methacrylate.
- the polymer component among these, the point that the cross-linking reaction with the cyclic siloxane compound [A] is easily promoted, the point that the compatibility with the cyclic siloxane compound [A] is better, and the cyclic siloxane compound [A] In the point that the effect of improving heat resistance when used in combination with is high, a highly reliable liquid crystal element can be obtained, and is derived from polyamic acid, polyamic acid ester, polyimide, and a monomer having a polymerizable unsaturated bond. It is preferably at least one selected from the group consisting of polymers having the following structural units.
- the polymer component has a functional group capable of reacting with the crosslinkable group of the cyclic siloxane compound [A] (hereinafter, also referred to as “reactive functional group”).
- the reactive functional group can be appropriately designed according to the crosslinkable group of the cyclic siloxane compound [A].
- preferred examples of the polymer component will be described.
- the polyamic acid can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound.
- Tetracarboxylic dianhydride examples of the tetracarboxylic dianhydride used for the synthesis of polyamic acid include aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride. Things and the like.
- aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride
- alicyclic tetracarboxylic dianhydride examples include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5- (2,5-dioxotetrahydrofuran-3-yl) -3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1 , 3-dione, 5- (2,5-dioxotetrahydrofuran-3-yl) -8-methyl-3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 2,4,6,8-tetracide
- diamine compound used in the synthesis of the polyamic acid examples include aliphatic diamine, alicyclic diamine, aromatic diamine, diaminoorganosiloxane, and the like. Specific examples of these diamines include metaxylylenediamine, 1,3-propanediamine, hexamethylenediamine and the like as aliphatic diamines; 1,4-diaminocyclohexane and 4,4'-methylenebis as alicyclic diamines (Cyclohexylamine) and the like; As aromatic diamines, hexadecanooxy-2,4-diaminobenzene, octadecanoxy-2,4-diaminobenzene, octadecanoxy-2,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3,5 -Diaminobenzene, chol
- Polyamic acid can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound, if necessary, with a molecular weight modifier (for example, acid monoanhydride or monoamine).
- a molecular weight modifier for example, acid monoanhydride or monoamine.
- the ratio of the tetracarboxylic dianhydride and the diamine compound used in the synthesis reaction of the polyamic acid is such that the acid anhydride group of the tetracarboxylic dianhydride is 0.2 to 1 equivalent of the amino group of the diamine compound. A ratio of 2 equivalents is preferred.
- the synthesis reaction of the polyamic acid is preferably performed in an organic solvent.
- the reaction temperature is preferably from -20 ° C to 150 ° C, and the reaction time is preferably from 0.1 to 24 hours.
- the organic solvent used in the reaction include aprotic polar solvents, phenol solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like.
- organic solvents are N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, ⁇ -butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol And at least one selected from the group consisting of halogenated phenol and a solvent, or a mixture of one or more of these and another organic solvent (eg, butyl cellosolve, diethylene glycol diethyl ether, etc.).
- the amount (a) of the organic solvent used is such that the total amount (b) of tetracarboxylic dianhydride and diamine is 0.1 to 50% by mass based on the total amount (a + b) of the reaction solution. Is preferred.
- polyamic acid ester examples include [I] a method of reacting the polyamic acid obtained by the above synthesis reaction with an esterifying agent, [II] a method of reacting a tetracarboxylic diester with a diamine compound, and [III] a tetracarboxylic acid. A method of reacting an acid diester dihalide with a diamine compound, or the like.
- the polyamic acid ester contained in the liquid crystal aligning agent may have only an amic acid ester structure, or may be a partially esterified product having both an amic acid structure and an amic acid ester structure.
- the polyimide can be obtained, for example, by dehydrating and ring-closing the polyamic acid synthesized as described above to imidize the polyamic acid.
- the imidation ratio of the polyimide is preferably 20 to 99%, more preferably 30 to 90%.
- the imidation ratio is a percentage of the number of imide ring structures to the total of the number of amic acid structures and the number of imide ring structures of the polyimide. Note that a part of the imide ring may be an isoimide ring.
- the dehydration and ring closure of the polyamic acid is preferably carried out by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating as necessary.
- the dehydrating agent include acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride.
- the amount of the dehydrating agent used is preferably 0.01 to 20 mol per 1 mol of the amic acid structure of the polyamic acid.
- the dehydration ring-closing catalyst for example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used.
- the amount of the dehydration ring-closing catalyst used is preferably 0.01 to 10 mol per 1 mol of the dehydrating agent used.
- Examples of the organic solvent used for the dehydration ring-closing reaction include the organic solvents exemplified as those used for the synthesis of polyamic acid.
- the reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C.
- the reaction time is preferably 1.0 to 120 hours.
- polymer having a structural unit derived from a monomer having a polymerizable unsaturated bond examples include, for example, a (meth) acryl compound as a monomer having a polymerizable unsaturated bond And a polymer (poly (meth) acrylate, styrene-maleimide copolymer, polystyrene, polymaleimide) obtained by using one or more of a maleimide compound and a styrene compound.
- the polymer [Pm] is preferably composed of poly (meth) acrylate and a styrene-maleimide-based copolymer in that the orientation group is easily introduced and the reliability of the obtained liquid crystal element is more favorable. It is at least one selected from the group.
- the copolymer is a styrene-maleimide copolymer
- the copolymer further has a structural unit derived from a monomer different from the styrene compound and the maleimide compound (for example, a (meth) acryl compound or the like). May be.
- the term “alignment group” refers to a group capable of giving a pretilt angle to liquid crystal molecules in a liquid crystal layer when a liquid crystal alignment film is disposed adjacent to the liquid crystal layer. Specific examples include a group capable of providing a pretilt angle to liquid crystal molecules without irradiation with light (hereinafter, also referred to as a “vertical alignment group”) and a photo alignment group.
- the vertical alignment group include, for example, an alkyl group having 4 to 20 carbon atoms, an alkoxy group having 4 to 20 carbon atoms, a fluoroalkyl group having 4 to 20 carbon atoms, a fluoroalkoxy group having 4 to 20 carbon atoms, 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) are directly or divalent linking groups (eg, an oxygen atom, -CO- or -COO-) And a group having a mesogen structure and a group having a steroid skeleton.
- an alkyl group having 4 to 20 carbon atoms an alkoxy group having 4 to 20 carbon atoms
- a fluoroalkyl group having 4 to 20 carbon atoms a fluoroalkoxy group having 4 to 20 carbon atoms
- Two or more rings are directly or divalent linking groups
- the monomer used for the synthesis of the polymer [Pm] is not particularly limited as long as it has a polymerizable unsaturated bond, and examples thereof include a (meth) acryloyl group, a vinyl group, a styryl group, a vinylphenyl group, and a maleimide group. And a compound having a polymerizable unsaturated bond.
- these compounds include unsaturated carboxylic acids such as (meth) acrylic acid, ⁇ -ethylacrylic acid, maleic acid, fumaric acid, and vinylbenzoic acid: alkyl (meth) acrylate (for example, (meth) acrylic Methyl acrylate, 2-ethylhexyl (meth) acrylate), cycloalkyl (meth) acrylate, benzyl (meth) acrylate, trimethoxysilylpropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, Unsaturated carboxylic esters such as glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, and 4-hydroxybutyl glycidyl ether: maleic anhydride (Meth) acrylic compounds such as unsaturated polycarboxylic anhydrides such as
- the polymer [Pm] is a polymer having a photo-alignment group
- a compound having a photo-alignment group may be used as the monomer having a polymerizable unsaturated bond.
- the compound having a photo-alignment group include a maleimide compound having a cinnamic acid structure and a (meth) acryl compound having a cinnamic acid structure.
- the monomer having a polymerizable unsaturated bond one kind may be used alone, or two or more kinds may be used in combination.
- “(meth) acryloyl” means “acryloyl” and “methacryloyl”.
- “(Meth) acryl” means “acrylol” and “methacryl”.
- the polymer [Pm] can be obtained, for example, by polymerizing a monomer having a polymerizable unsaturated bond in the presence of a polymerization initiator.
- a polymerization initiator As the polymerization initiator to be used, 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2, An azo compound such as 4-dimethylvaleronitrile) is preferred.
- the use ratio of the polymerization initiator is preferably 0.01 to 30 parts by mass based on 100 parts by mass of all the monomers used in the reaction.
- the polymerization reaction is preferably performed in an organic solvent.
- Examples of the organic solvent used in the reaction include alcohols, ethers, ketones, amides, esters, and hydrocarbon compounds. Diethylene glycol ethyl methyl ether and propylene glycol monomethyl ether acetate are preferred.
- the reaction temperature is preferably 30 ° C. to 120 ° C., and the reaction time is preferably 1 to 36 hours.
- the amount (a) of the organic solvent used should be such that the total amount (b) of the monomers used in the reaction is 0.1 to 60% by mass based on the total amount (a + b) of the reaction solution. Is preferred.
- the weight average molecular weight (Mw) of the polymer component in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably from 1,500 to 500,000, more preferably from 2,500 to 100,000. Is more preferred.
- the reaction solution may be directly used for preparation of a liquid crystal aligning agent. It may be used for preparing an alignment agent.
- the method for isolating the polymer is not particularly limited, and can be performed according to a known method.
- the polymer component is a polymer having a photo alignment group.
- the photo-alignable group refers to a functional group capable of imparting anisotropy to a film by a photo-reaction such as photo-isomerization reaction, photo-dimerization reaction, photo-fleece rearrangement reaction or photo-decomposition reaction by light irradiation.
- the photo-alignment group include, for example, an azobenzene-containing group containing azobenzene or a derivative thereof as a basic skeleton, a cinnamic acid structure-containing group containing cinnamic acid or a derivative thereof (cinnamic acid structure) as a basic skeleton, and chalcone or a derivative thereof.
- the photo-alignment group is preferably at least one selected from the group consisting of an azobenzene-containing group, a cinnamic acid structure-containing group, a chalcone-containing group, a stilbene-containing group, a cyclobutane-containing structure, and a phenylbenzoate-containing group.
- an azobenzene-containing group a cinnamic acid structure-containing group, a chalcone-containing group, a stilbene-containing group, a cyclobutane-containing structure, and a phenylbenzoate-containing group.
- a cinnamic acid structure-containing group or a cyclobutane-containing structure is preferred.
- the polymer having a photo-alignable group can be obtained by, for example, (1) a method of obtaining a polymer having a photo-alignable group by polymerization using a monomer having the photo-alignable group; It can be obtained by, for example, a method of reacting a polymer with a carboxylic acid having a photo-alignment group.
- the content ratio of the photo-alignment group in the polymer is appropriately set according to the type of the photo-alignment group so as to impart a desired liquid crystal alignment ability to the coating film.
- the content of the photo-orientable group is preferably at least 5 mol%, based on all the structural units of the polymer having the photo-orientable group. More preferably, it is 60 mol%.
- the content of the photo-alignment group is preferably 50 mol% or more, and more preferably 80 mol% or more, based on all structural units of the polymer having the photo-alignment group. Is more preferable.
- the polymer having a photo-alignment group one type may be used alone, or two or more types may be used in combination.
- the polymer component to be contained in the liquid crystal aligning agent may be one kind alone, but is preferably a polymer blend containing two or more kinds of polymers.
- the two or more kinds of polymers may be the same kind of polymer (for example, polyamic acid and polyamic acid), and the kinds of monomers used may be different from each other, or different kinds of polymers may be used. (For example, polyamic acid and polymethacrylate).
- a crosslinking agent is blended in the polymer blend system, if the dispersibility of the crosslinking agent in the liquid crystal alignment agent is not sufficient, the crosslinking reaction of the polymer by the crosslinking agent will not be efficiently performed, and the effect of the crosslinking agent will be sufficiently enhanced.
- a first polymer and a second polymer having a higher polarity than the first polymer are contained in the liquid crystal aligning agent.
- the second polymer having a high polarity is unevenly distributed in the lower layer
- the first polymer is unevenly distributed in the upper layer, so that phase separation is preferably caused.
- Preferred embodiments of the polymer component of the liquid crystal aligning agent include the following (I) to (III).
- (I) An embodiment in which the first polymer and the second polymer are polymers selected from the group consisting of polyamic acids, polyamic acid esters, and polyimides.
- one of the first polymer and the second polymer is a kind of polymer selected from the group consisting of a polyamic acid, a polyamic acid ester and a polyimide, and the other is a polymer [Pm]. .
- III An embodiment in which the first polymer and the second polymer are polymers [Pm].
- the total content of the polyamic acid, the polyamic acid ester and the polyimide is included in the liquid crystal aligning agent from the viewpoint of reducing costs while sufficiently obtaining the improvement effect of the polymer [Pm].
- the amount is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 50 to 90% by mass, based on the total amount of the polymer components.
- the polymer [Pm] is a polymer having a photo alignment group, so that the liquid crystal alignment is high. This is preferable in that an alignment film can be obtained.
- the content ratio of the polymer component in the liquid crystal aligning agent is based on the total mass of the solid content contained in the liquid crystal aligning agent (total mass of components other than the solvent of the liquid crystal aligning agent). On the other hand, it is preferably at least 50% by mass, more preferably at least 60% by mass, and even more preferably at least 70% by mass.
- the cyclic siloxane compound [A] is a cyclic compound having one cyclic skeleton in a molecule by a siloxane bond (Si—O bond), and has a crosslinkable group.
- the crosslinkable group is not particularly limited as long as it is a group capable of forming a crosslinked structure by covalently bonding to another group. Examples thereof include an oxiranyl group, an oxetanyl group, a (meth) acryloyl group, an allyl group, a vinylphenyl group, and a cyclic group. Examples include a carbonate group, a methylol group, and an amino group.
- the crosslinkable group is preferably at least one selected from the group consisting of an oxiranyl group, an oxetanyl group, and a (meth) acryloyl group, from the viewpoint that the storage stability of the liquid crystal alignment agent can be increased, and an oxiranyl group is particularly preferred.
- an oxiranyl group is particularly preferred.
- (meth) acryloyl has a meaning including “acryloyl” and “methacryloyl”.
- the number of the crosslinkable groups contained in one molecule of the cyclic siloxane compound [A] is preferably two or more from the viewpoint that the effect of improving the heat resistance and light resistance of the obtained liquid crystal element can be sufficiently obtained.
- the number is more preferably 4 or more, and further preferably 4 or more.
- the number of the crosslinkable groups in one molecule of the cyclic siloxane compound [A] is such that the compatibility with the polymer component is better, the dispersibility in the liquid crystal aligning agent can be higher, and From the viewpoint of suppressing performance degradation due to film shrinkage of the liquid crystal alignment film, the number is preferably 10 or less, and more preferably 8 or less.
- the crosslinkable group of the cyclic siloxane compound [A] reacts with the reactive functional group of the polymer component by heating during film formation to form a crosslinked structure. Is formed.
- the combination of the crosslinkable group and the reactive functional group is appropriately selected depending on storage stability, ease of introduction into a polymer, reactivity to heat or light, and the like.
- the crosslinkable group is an epoxy group
- the reactive functional group includes a carboxyl group, a hydroxyl group, an amino group, and the like, and is preferably a carboxyl group in terms of good storage stability. .
- examples of the reactive functional group include a thiol group and a (meth) acryloyl group.
- examples of the reactive functional group include a thiol group and a vinyl group.
- the crosslinkable group is an amino group
- the reactive functional group includes a carboxyl group, a hydroxyl group, and an epoxy group. Groups, halogen atoms and the like.
- examples of the reactive functional group include an amino group, a hydroxyl group, a carboxyl group, an epoxy group, and an acid anhydride group, and when the crosslinkable group is a methylol group, the reactive functional group Examples of the group include an epoxy group, an amino group, a hydroxyl group, a carboxyl group and the like. However, it is not limited to these combinations.
- the cyclic siloxane compound [A] is preferably a compound represented by the following formula (1).
- R 1 to R 6 are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, provided that at least one of R 1 to R 6 is is a monovalent organic group having a crosslinkable group .n If it .n is 2 or an integer of 1 to 18, a plurality of R 1 may be the same as or different from each other, a plurality of R 2 are each It may be the same or different.
- R 1 to R 6 are a monovalent organic group
- specific examples thereof include a monovalent hydrocarbon group having 1 to 20 carbon atoms and at least one of the monovalent hydrocarbon groups.
- R 10 is a monovalent hydrocarbon group having a hydrogen atom or a C 1-10) monovalent group Q2 having, at least one of the monovalent group Q2 Examples include a group Q3 in which a hydrogen atom is replaced by a crosslinkable group, and these groups may have a substituent. Examples of the substituent include a hydroxyl group and a halogen atom.
- R 1 to R 6 are a monovalent hydrocarbon group, the monovalent hydrocarbon group is preferably an alkyl group, an alkenyl group or a phenyl group, and more preferably an alkyl group.
- R 1 to R 6 are carbon atoms in that the dispersibility of the cyclic siloxane compound [A] in the liquid crystal aligning agent can be improved, and the compatibility with the polymer component and the solubility in a solvent can be improved. It is preferably a monovalent organic group having 1 to 20 carbon atoms, and is preferably a monovalent hydrocarbon group having 1 to 20 carbon atoms, a monovalent group Q1, a monovalent group Q2 or a monovalent group Q3. More preferred.
- the carbon number of R 1 to R 6 is preferably 1 to 15, more preferably 1 to 10.
- R 1 to R 6 are a monovalent organic group having a crosslinkable group
- the monovalent organic group having a crosslinkable group is preferably a group represented by the following formula (2).
- * 1 -R 7 -X 1 (2) (In the formula (2), R 7 is a divalent group having a chain structure, and X 1 is a monovalent group having a crosslinkable group. “* 1 ” is a bond to a silicon atom. Is represented.)
- the chain structure of R 7 preferably has —O— or — between the carbon-carbon bond of the alkanediyl group having 1 to 10 carbon atoms or the alkanediyl group having 2 to 10 carbon atoms. It is a divalent group having S- and may have a substituent. Examples of the substituent include a hydroxyl group and a halogen atom. R 7 preferably has 1 to 7 carbon atoms, more preferably 2 to 5 carbon atoms.
- X 1 is preferably a monovalent group having an oxiranyl group, an oxetanyl group, a (meth) acryloyl group, an allyl group, a vinylphenyl group, a cyclic carbonate group, a methylol group, or an amino group. From the viewpoint of properties, it is more preferably a monovalent group having an oxiranyl group, an oxetanyl group or a (meth) acryloyl group, and particularly preferably a monovalent group having an epoxy group (an oxiranyl group or an oxetanyl group). .
- the monovalent group having an epoxy group include an epoxy group, a glycidyloxy group, and an epoxycyclohexyl group.
- the two monovalent groups bonded to the silicon atom in the above formula (1) are groups in which at least one (R 1 , R 3 and R 5 ) is a group represented by the above formula (2) and the other ( Preferably, R 2 , R 4 and R 6 ) are monovalent hydrocarbon groups having 1 to 10 carbon atoms.
- R 2 , R 4 and R 6 are more preferably an alkyl group having 1 to 5 carbon atoms, further preferably a methyl group or an ethyl group.
- n is preferably 1 to 10, and is preferably 1 to 6, from the viewpoints of dispersibility of the cyclic siloxane compound [A] in the liquid crystal aligning agent, compatibility with the polymer component, and availability of the material. More preferably, it is particularly preferably 1 to 4.
- the cyclic siloxane compound [A] may further have a photoreactive group.
- the cyclic siloxane compound [A] has a photoreactive group, self-crosslinking can be caused by a thermal reaction of the photoreactive group, and when a liquid crystal device is obtained by PSA treatment, the light resistance is equivalent to that of the crosslinkable group. And heat resistance can be obtained.
- the photoreactive group a group having a carbon-carbon unsaturated bond is preferable, and examples thereof include a (meth) acryloyl group, a vinylphenyl group, and a vinyl group.
- a (meth) acryloyl group is particularly preferable in that it has high photoreactivity and self-crosslinking easily occurs due to a thermal reaction of the photoreactive group.
- the photoreactive group is a functional group that does not cause a cross-linking reaction with a reactive functional group introduced into the polymer component in order to cross-link the polymer component with the cyclic siloxane compound [A].
- the crosslinkable group contained in the cyclic siloxane compound [A] is preferably a group having no polymerizable unsaturated bond, and specifically, an epoxy group , An amino group, a cyclic carbonate group, and a methylol group.
- the number of photoreactive groups is preferably one or more, and more preferably two or more. Further, the number of photoreactive groups is preferably 4 or less, more preferably 2 or less, in order to sufficiently secure the number of cross-linkable groups to be introduced.
- the molecular weight of the cyclic siloxane compound [A] ensures that it is easily dispersed in the liquid crystal aligning agent, that it has better compatibility with the polymer component and that it has better solubility in solvents, and that the film strength of the liquid crystal aligning film is sufficiently secured. From the viewpoint that it can be performed, it is preferably less than 1000, more preferably 900 or less, and further preferably 800 or less.
- the molecular weight of the cyclic siloxane compound [A] is preferably 100 or more, more preferably 200 or more, from the viewpoint of suppressing the volatilization of the cyclic siloxane compound [A].
- cyclic siloxane compound [A] examples include, for example, compounds represented by the following formulas (A-1) to (A-10).
- Commercial products may be used as the cyclic siloxane compound [A].
- Examples of commercially available products include CS-697 and CS-783 (all manufactured by Sigma-Aldrich), KR-470, X-40-2670, and X-40-2678 (all manufactured by Shin-Etsu Silicone). .
- R is a hydrogen atom or a methyl group
- n is an integer of 0 to 18.
- the content of the cyclic siloxane compound [A] is based on 100 parts by mass of the total amount of the polymer components contained in the liquid crystal aligning agent because the effect of improving the light resistance and heat resistance of the obtained liquid crystal element can be sufficiently increased. On the other hand, it is preferably at least 0.01 part by mass, more preferably at least 0.05 part by mass, and even more preferably at least 0.1 part by mass.
- the content of the cyclic siloxane compound [A] is 40 parts by mass with respect to 100 parts by mass of the total amount of the polymer components contained in the liquid crystal aligning agent in that the film shrinkage at the time of forming the liquid crystal alignment film can be suppressed. Parts by weight or less, more preferably 30 parts by weight or less, even more preferably 20 parts by weight or less.
- the cyclic siloxane compound [A] one type may be used alone, or two or more types may be used in combination.
- the liquid crystal aligning agent of the present disclosure may contain, if necessary, other compounds other than the polymer component and the cyclic siloxane compound [A].
- specific examples thereof include epoxy compounds (eg, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N , N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N, N-diglycidyl-aminomethylcyclohexane, 1,6-hexanediol di (meth) acrylate, pentaerythritol tri (meth) acrylate ), Functional silane compounds (eg, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxy
- the compounding ratio of the other compounds can be appropriately selected according to each compound as long as the effects of the present disclosure are not impaired.
- the content of the compound is 5 mass% with respect to the total amount of the cyclic siloxane compound [A] contained in the liquid crystal aligning agent. % Or less, more preferably 1% by mass or less.
- the liquid crystal aligning agent of the present disclosure is prepared as a solution composition in which a polymer component, a cyclic siloxane compound [A], and a component optionally mixed are optionally dissolved in an organic solvent.
- the organic solvent include aprotic polar solvents, phenol solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like.
- the solvent component may be one kind of these or a mixed solvent of two or more kinds.
- first solvent a solvent having high polymer solubility and leveling property
- second solvent a solvent having good wettability and spreadability
- the solvent include a first solvent such as N-methyl-2-pyrrolidone, ⁇ -butyrolactone, ⁇ -butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4-hydroxy-4-methyl -2-pentanone, diisobutyl ketone, ethylene carbonate, propylene carbonate, N-ethyl-2-pyrrolidone, N- (n-pentyl) -2-pyrrolidone, N- (t-butyl) -2-pyrrolidone, N-methoxypropyl -2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 3-butoxy-N, N-dimethylpropanamide, 3-methoxy-N, N-dimethylpropanamide and the like;
- the second solvent include ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol monomethyl ether, ethylene glycol monoethy
- Ether propylene glycol monomethyl ether acetate, 3-methoxy-1-butanol, cyclopentanone, butyl lactate, butyl acetate, methylmethoxypropionate, ethylethoxypropionate, isoamylpropionate, isoamylisobutyrate, Propylene glycol diacetate, dipropylene glycol Monomethyl ether, propylene glycol monobutyl ether, di isopentyl ether, etc., can be exemplified respectively.
- the solvent may be used alone, but is preferably a mixed solvent of the first solvent and the second solvent.
- the solid content concentration (the ratio of the total mass of components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) in the liquid crystal aligning agent is appropriately selected in consideration of viscosity, volatility, and the like. It is in the range of 1 to 10% by mass.
- the solid content concentration is less than 1% by mass, the thickness of the coating film becomes too small, and it becomes difficult to obtain a good liquid crystal alignment film.
- the solid content concentration exceeds 10% by mass, the thickness of the coating film becomes excessively large, so that it is difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases, thereby deteriorating the coatability. There is a tendency.
- the liquid crystal alignment film of the present disclosure is formed by the liquid crystal alignment agent prepared as described above. Further, the liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above.
- the operation mode of the liquid crystal in the liquid crystal element is not particularly limited. For example, TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS (In-Plane Switching) type, FFS (Fringe) It can be applied to various modes such as a Field Switching (OCB) type, an OCB (Optically Compensated Bend) type, and a PSA (Polymer Sustained Alignment) type.
- the liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, a substrate to be used differs depending on a desired operation mode. Steps 2 and 3 are common to each operation mode.
- a liquid crystal aligning agent is applied to each substrate surface of a pair of substrates, and preferably, a coating film is formed on the substrates by heating the applied surfaces.
- a transparent substrate made of glass such as float glass and soda glass; and a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, and poly (alicyclic olefin) can be used.
- NESA film As the transparent conductive film provided on one surface of the substrate, NESA film (US PPG registered trademark) made of tin oxide (SnO 2), indium oxide - ITO made of tin oxide (In 2 O 3 -SnO 2) film Etc. can be used.
- a TN, STN, or VA liquid crystal element two substrates provided with a patterned transparent conductive film are used.
- a substrate provided with electrodes patterned in a comb shape and a counter substrate provided with no electrodes are used.
- the application of the liquid crystal aligning agent to the substrate is preferably performed on the electrode forming surface by an offset printing method, a flexographic printing method, a spin coating method, a roll coater method, or an inkjet printing method.
- preheating is preferably performed for the purpose of preventing the applied liquid crystal aligning agent from dripping.
- the pre-bake temperature is preferably 30 to 200 ° C.
- the pre-bake time is preferably 0.25 to 10 minutes.
- a baking (post-baking) step is performed for the purpose of completely removing the solvent and, if necessary, thermally imidizing the amic acid structure in the polymer component.
- the firing temperature (post-bake temperature) at this time is preferably from 80 to 250 ° C, and more preferably from 80 to 200 ° C.
- the post-bake time is preferably 5 to 200 minutes.
- the thickness (film thickness) of the film thus formed is preferably 0.001 to 1 ⁇ m.
- ⁇ Step 2 Orientation treatment>
- a process (alignment process) of imparting liquid crystal alignment capability to the coating film formed in the above step 1 is performed. Thereby, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film.
- a rubbing treatment in which the coating film formed on the substrate is rubbed in a certain direction with a roll around which a cloth made of fibers such as nylon, rayon, cotton, or the like is wound, or light irradiation is performed on the coating film formed on the substrate.
- a photo-alignment treatment or the like that imparts liquid crystal alignment capability to the coating film to form a photo-alignment film can be used.
- the coating film formed in the above step 1 can be used as it is as a liquid crystal alignment film.
- the film may be subjected to an orientation treatment.
- a liquid crystal alignment film suitable for a vertical alignment type liquid crystal element can be suitably used for a PSA type liquid crystal element.
- the light irradiation is a method of irradiating the coating film after the post-baking step, a method of irradiating the coating film after the pre-baking step and before the post-baking step, a pre-baking step and a post-baking step
- a method of irradiating the coating film while heating the coating film can be used.
- the radiation for irradiating the coating film for example, ultraviolet light and visible light including light having a wavelength of 150 to 800 nm can be used.
- it is ultraviolet light including light having a wavelength of 200 to 400 nm.
- the radiation is polarized, it may be linearly polarized or partially polarized.
- the irradiation may be performed from a direction perpendicular to the substrate surface, may be performed from an oblique direction, or may be performed in combination.
- the irradiation direction for non-polarized radiation is an oblique direction.
- Examples of the light source used include a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, and an excimer laser.
- the radiation dose on the substrate surface is preferably from 400 to 50,000 J / m 2 , more preferably from 1,000 to 20,000 J / m 2 .
- the surface of the substrate is washed with, for example, water, an organic solvent (eg, methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.) or a mixture thereof. May be performed, or a process of heating the substrate may be performed.
- an organic solvent eg, methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.
- Step 3 Construction of liquid crystal cell> Two substrates on which the liquid crystal alignment film is formed as described above are prepared, and a liquid crystal cell is manufactured between the two substrates so that the liquid crystal is arranged adjacent to the liquid crystal alignment film.
- two substrates are opposed to each other with a gap so that a liquid crystal alignment film faces each other, the peripheral portions of the two substrates are bonded with a sealant, and the substrate surface and the sealant are bonded.
- a method of injecting and filling a liquid crystal into a cell gap surrounded by a circle to seal an injection hole a method by an ODF method, and the like.
- an epoxy resin containing a hardener and aluminum oxide spheres as a spacer can be used.
- the liquid crystal include a nematic liquid crystal and a smectic liquid crystal, and among them, the nematic liquid crystal is preferable.
- the PSA mode after the liquid crystal cell is constructed, a process of irradiating the liquid crystal cell with light with a voltage applied between the conductive films of the pair of substrates is performed.
- a liquid crystal cell is constructed in the same manner as described above except that a photopolymerizable monomer is injected or dropped together with a liquid crystal between a pair of substrates having a conductive film.
- a photopolymerizable monomer a conventionally known compound can be used.
- it is a polyfunctional (meth) acrylic monomer.
- the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates.
- the voltage applied here may be, for example, 5 to 50 V DC or AC.
- light to be applied for example, ultraviolet light and visible light including light having a wavelength of 150 to 800 nm can be used.
- ultraviolet rays containing light having a wavelength of 300 to 400 nm are preferable.
- a light source of the irradiation light for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used.
- the light irradiation amount is preferably from 1,000 to 200,000 J / m 2 , more preferably from 1,000 to 150,000 J / m 2 .
- a polarizing plate is attached to the outer surface of the liquid crystal cell as required, thereby forming a liquid crystal element.
- the polarizing plate include a polarizing plate in which a polarizing film called “H film” in which polyvinyl alcohol is stretched and oriented and absorbs iodine is sandwiched by a cellulose acetate protective film or a polarizing plate composed of the H film itself.
- the liquid crystal element of the present disclosure can be effectively applied to various uses, for example, a clock, a portable game, a word processor, a notebook computer, a car navigation system, a camcorder, a PDA, a digital camera, a mobile phone, a smartphone, and various monitors. It can be applied to various display devices such as a liquid crystal television and an information display, a light control film, a retardation film and the like.
- the solution viscosity, weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw / Mn), imidation ratio and epoxy equivalent of the polymer were measured by the following methods.
- ⁇ Weight average molecular weight, number average molecular weight and molecular weight distribution> Mw and Mn were measured by gel permeation chromatography (GPC) under the following conditions.
- Mw / Mn The molecular weight distribution (Mw / Mn) was calculated from the obtained Mw and Mn.
- Apparatus "GPC-101" of Showa Denko KK GPC column: “GPC-KF-801”, “GPC-KF-802”, “GPC-KF-803” and “GPC-KF-804” manufactured by Shimadzu GC Co., Ltd.
- Imidation ratio (%) (1-A 1 / A 2 ⁇ ⁇ ) ⁇ 100 (E-1) (In the formula (E-1), A 1 is the peak area derived from the proton of the NH group appearing near the chemical shift of 10 ppm, A 2 is the peak area derived from other protons, and ⁇ is the precursor of the polymer ( It is the number ratio of other protons to one proton of NH group in polyamic acid).
- a small amount of the obtained polyamic acid solution was separated and concentrated under reduced pressure, and the solution viscosity measured as a solution having a concentration of 10% by mass was 80 mPa ⁇ s.
- 600 g of NMP was added to the obtained polyamic acid solution, 136 g of pyridine and 105 g of acetic anhydride were added, and a dehydration ring closure reaction was performed at 110 ° C. for 4 hours.
- the solvent in the system is solvent-substituted with new ⁇ -butyrolactone and further concentrated to obtain a solution containing 20% by mass of a polyimide polymer (PI-1) having an imidization ratio of about 85%. 600 g were obtained.
- a small amount of this solution was fractionated, ⁇ -butyrolactone was added thereto, and the solution viscosity measured as a solution having a concentration of 6.0% by mass was 22 mPa ⁇ s.
- Synthesis Example 2-4 Synthesis of Styrene-Maleimide Copolymer
- Polymerization was carried out in the same manner as in Synthesis Example 2-3 except that Compound (MI-2) was used instead of Compound (MI-1) as the polymerization monomer in Synthesis Example 2-3.
- the precipitate was filtered and vacuum dried at room temperature for 8 hours to obtain a polymer (StMI-B) which was a styrene-maleimide copolymer.
- the weight average molecular weight Mw measured by GPC in terms of polystyrene was 25,000, and the molecular weight distribution Mw / Mn was 2.
- polyorganosiloxane (PS-1) The epoxy equivalent of this epoxy group-containing polyorganosiloxane (hereinafter referred to as “polyorganosiloxane (PS-1)”) was 186 g / equivalent.
- Example 1 Preparation of Liquid Crystal Alignment Agent (AL-1)
- the above-prepared liquid crystal aligning agent (AL-1) is applied using a spinner, and a hot plate at 80 ° C. For 1 minute. Thereafter, the coating was heated at 230 ° C. for 1 hour in an oven in which the inside of the storage was replaced with nitrogen to form a coating film having a thickness of 0.1 ⁇ m.
- the coating film surface was irradiated with polarized ultraviolet light 1,000 J / m 2 containing a 313 nm bright line from a direction inclined by 40 ° with respect to the substrate normal, Liquid crystal alignment ability was imparted to the coating film.
- the same operation was repeated to prepare a pair (two) of substrates having a liquid crystal alignment film.
- An epoxy resin adhesive containing aluminum oxide spheres having a diameter of 3.5 ⁇ m was applied by screen printing to the outer periphery of the surface having the liquid crystal alignment film of one of the pair of substrates on which the liquid crystal alignment film was formed.
- liquid crystal alignment film surfaces of the pair of substrates are opposed to each other, and the substrates are pressed so that the projection direction of the optical axis of the ultraviolet light of each substrate to the substrate surface is antiparallel.
- a negative liquid crystal (MLC-6608, manufactured by Merck) was filled into the gap between the substrates from the liquid crystal injection port, and the liquid crystal injection port was sealed with an epoxy-based adhesive.
- MLC-6608, manufactured by Merck was filled into the gap between the substrates from the liquid crystal injection port, and the liquid crystal injection port was sealed with an epoxy-based adhesive.
- it was heated at 130 ° C. and then gradually cooled to room temperature to obtain a liquid crystal cell.
- a polarizing plate is attached to both outer surfaces of the substrate such that the polarization directions thereof are orthogonal to each other, and that the angle of 45 ° is formed between the direction of projection of the optical axis of the ultraviolet light of the liquid crystal alignment film onto the substrate surface.
- an optical vertical liquid crystal display device was manufactured.
- the reduction amount ⁇ is 1% or less, the heat resistance is “very good ())”, and when the reduction amount ⁇ is more than 1% and 2% or less, the heat resistance is “good ( ⁇ )”.
- the light resistance is “very good ())”, and when the reduction amount ⁇ is more than 1% and 2% or less, the light resistance is “good ( ⁇ )”.
- the amount ⁇ was more than 2% and 3% or less, the light resistance was evaluated as “good ( ⁇ )”, and when the decrease ⁇ exceeded 3%, the light resistance was evaluated as “poor (x)”. As a result, in this example, the light resistance was evaluated as “very good ( ⁇ )”.
- Examples 2 to 9 and Comparative Examples 1, 2, 4, 6 A liquid crystal aligning agent was prepared with the same solvent composition and solid concentration as in Example 1 except that the composition was changed as shown in Tables 1 to 3 below. Further, an optical vertical liquid crystal display element was manufactured in the same manner as in Example 1 using each liquid crystal aligning agent, and various evaluations were performed. The results are shown in Tables 1 to 3 below.
- Example 10 Preparation of Liquid Crystal Alignment Agent (AL-10) A polymer containing 100 parts by mass of the polymer (PA-1) obtained in Synthesis Example 2-2 and a polymer obtained in Synthesis Example 2-4 were used. A liquid crystal aligning agent (AL-10) was prepared with the same solvent composition and solid content as in Example 1 except that the combined amount (StMI-B) was changed to 5 parts by mass.
- Liquid Crystal Composition 5% by mass of a liquid crystal compound represented by the above formula (L1-1) and 10% by mass of a nematic liquid crystal (MLC-6608, manufactured by Merck & Co.) and the above formula (L2-1)
- the liquid crystal composition LC1 was obtained by adding and mixing 0.3% by mass of the photopolymerizable compound.
- liquid crystal aligning agent (AL-10) prepared as described above is applied to a liquid crystal alignment film printing machine (Nihon Photo Printing Co., Ltd.) (Manufactured by Co., Ltd.), and heated (pre-baked) on a hot plate at 80 ° C. for 2 minutes to remove the solvent, and then heated (post-baked) on a hot plate at 230 ° C. for 10 minutes (average).
- a coating film having a thickness of 0.06 ⁇ m was formed. These coating films were subjected to ultrasonic cleaning in ultrapure water for 1 minute, and then dried in a 100 ° C. clean oven for 10 minutes to obtain a pair (two) of substrates having a liquid crystal alignment film.
- the electrode pattern used is the same kind of pattern as the electrode pattern in the PSA mode.
- an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 ⁇ m is applied to the outer edge of the surface having the liquid crystal alignment film of one of the pair of substrates, and then the liquid crystal alignment films are overlapped with each other. They were pressed together and the adhesive was cured.
- a liquid crystal cell was manufactured by filling the liquid crystal composition LC1 prepared above between a pair of substrates from the liquid crystal injection port and sealing the liquid crystal injection port with an acrylic photocurable adhesive.
- an alternating current of 10 V having a frequency of 60 Hz is applied between the conductive films of the liquid crystal cell, and in a state where the liquid crystal is driven, an irradiation amount of 100,000 J / m 2 is applied by using an ultraviolet irradiation apparatus using a metal halide lamp as a light source.
- an ultraviolet irradiation apparatus using a metal halide lamp as a light source.
- This irradiation amount is a value measured using a light meter measured based on a wavelength of 365 nm.
- Examples 11 to 13 and Comparative Examples 3 and 5 A liquid crystal aligning agent was prepared with the same solvent composition and solid content as in Example 10, except that the composition was changed as shown in Tables 2 and 3 below. Further, a PSA-type liquid crystal display element was manufactured in the same manner as in Example 10 using each liquid crystal aligning agent, and various evaluations were performed in the same manner as in Example 1. The results are shown in Tables 2 and 3 below.
- C-2 Polyorganosiloxane (PS-1) of Synthesis Example 2-5 above C-3: N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane (compound represented by the above formula (C-3))
- Comparative Example 1 using the compound (C-1) which is a polyfunctional siloxane compound having a chain structure in place of the cyclic siloxane compound [A], the light resistance was higher than that of the examples (Examples 1 to 3). And heat resistance was inferior to Examples 1 and 2.
- Comparative Examples 2 and 3 using polyorganosiloxane (PS-1) instead of cyclic siloxane compound [A] light resistance and heat resistance were higher than those in Examples (Examples 1 to 3 and Examples 10 to 13). Both were inferior.
- Comparative Example 6 using Compound (C-3), which is a conventionally used crosslinking agent was inferior in both light resistance and heat resistance as compared with the Examples. From these results, it was found that by using the cyclic siloxane compound [A] as the crosslinking agent, a liquid crystal element excellent in heat resistance and light resistance can be obtained.
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Abstract
Description
[1] 重合体成分と、架橋性基を有する環状シロキサン化合物[A]と、を含有する、液晶配向剤。
[2] 上記[1]の液晶配向剤を用いて形成された液晶配向膜。
[3] 上記[2]の液晶配向膜を具備する液晶素子。
[4] 上記[1]の液晶配向剤を一対の基板のそれぞれの基板面に塗布し、前記基板面に光を照射することにより光配向膜を形成する工程と、前記液晶配向膜が形成された一対の基板を、液晶層を挟んで前記光配向膜が対向するように配置して液晶セルを構築する工程と、を含む、液晶素子の製造方法。
[5] 上記[1]の液晶配向剤を、導電膜を有する一対の基板のそれぞれの前記導電膜上に塗布して塗膜を形成する工程と、前記塗膜が形成された一対の基板を、液晶層を挟んで前記塗膜が対向するように配置して液晶セルを構築する工程と、前記導電膜間に電圧を印加した状態で前記液晶セルに光照射する工程と、を含む、液晶素子の製造方法。
本開示の液晶配向剤は、重合体成分と添加剤成分とを含有する。また、添加剤成分として、架橋性基を有する環状シロキサン化合物[A]を含有する。以下に、液晶配向剤に含まれる各成分、及び必要に応じて任意に配合されるその他の成分について説明する。
液晶配向剤に含有される重合体成分は、環状シロキサン化合物[A]によって架橋される。重合体成分の主骨格の種類は特に限定されない。重合体成分の具体例としては、例えばポリアミック酸、ポリアミック酸エステル、ポリイミド、ポリオルガノシロキサン、ポリエステル、ポリアミド、ポリアミドイミド、ポリスチレン、ポリベンゾオキサゾール前駆体、ポリベンゾオキサゾール、セルロース誘導体、ポリアセタール、ポリマレイミド、スチレン-マレイミド系共重合体、又はポリ(メタ)アクリレートを主骨格とする重合体が挙げられる。なお、(メタ)アクリレートは、アクリレート及びメタクリレートを含むことを意味する。
ポリアミック酸は、テトラカルボン酸二無水物とジアミン化合物とを反応させることにより得ることができる。
・テトラカルボン酸二無水物
ポリアミック酸の合成に使用するテトラカルボン酸二無水物としては、例えば脂肪族テトラカルボン酸二無水物、脂環式テトラカルボン酸二無水物、芳香族テトラカルボン酸二無水物などを挙げることができる。これらの具体例としては、脂肪族テトラカルボン酸二無水物として、例えば1,2,3,4-ブタンテトラカルボン酸二無水物等を;
脂環式テトラカルボン酸二無水物として、例えば1,2,3,4-シクロブタンテトラカルボン酸二無水物、1,3-ジメチル-1,2,3,4-シクロブタンテトラカルボン酸二無水物、2,3,5-トリカルボキシシクロペンチル酢酸二無水物、5-(2,5-ジオキソテトラヒドロフラン-3-イル)-3a,4,5,9b-テトラヒドロナフト[1,2-c]フラン-1,3-ジオン、5-(2,5-ジオキソテトラヒドロフラン-3-イル)-8-メチル-3a,4,5,9b-テトラヒドロナフト[1,2-c]フラン-1,3-ジオン、2,4,6,8-テトラカルボキシビシクロ[3.3.0]オクタン-2:4,6:8-二無水物、シクロペンタンテトラカルボン酸二無水物、シクロヘキサンテトラカルボン酸二無水物等を;芳香族テトラカルボン酸二無水物として、例えばピロメリット酸二無水物、4,4’-(ヘキサフルオロイソプロピリデン)ジフタル酸無水物、エチレングリコールビスアンヒドロトリメート、4,4’-(ヘキサフルオロイソプロピリデン)ジフタル酸無水物、4,4’-カルボニルジフタル酸無水物等を、それぞれ挙げることができるほか、特開2010-97188号公報に記載のテトラカルボン酸二無水物を用いることができる。なお、テトラカルボン酸二無水物としては、1種を単独で又は2種以上組み合わせて使用することができる。
ポリアミック酸の合成に使用するジアミン化合物としては、例えば脂肪族ジアミン、脂環式ジアミン、芳香族ジアミン、ジアミノオルガノシロキサン等が挙げられる。これらジアミンの具体例としては、脂肪族ジアミンとして、メタキシリレンジアミン、1,3-プロパンジアミン、ヘキサメチレンジアミン等を;脂環式ジアミンとして、1,4-ジアミノシクロヘキサン、4,4’-メチレンビス(シクロヘキシルアミン)等を;
芳香族ジアミンとして、ヘキサデカノキシ-2,4-ジアミノベンゼン、オクタデカノキシ-2,4-ジアミノベンゼン、オクタデカノキシ-2,5-ジアミノベンゼン、コレスタニルオキシ-3,5-ジアミノベンゼン、コレステニルオキシ-3,5-ジアミノベンゼン、コレスタニルオキシ-2,4-ジアミノベンゼン、コレステニルオキシ-2,4-ジアミノベンゼン、3,5-ジアミノ安息香酸コレスタニル、3,5-ジアミノ安息香酸コレステニル、3,5-ジアミノ安息香酸ラノスタニル、3,6-ビス(4-アミノベンゾイルオキシ)コレスタン、3,6-ビス(4-アミノフェノキシ)コレスタン、2,4-ジアミノ-N,N-ジアリルアニリン、4-(4’-トリフルオロメトキシベンゾイロキシ)シクロヘキシル-3,5-ジアミノベンゾエート、1,1-ビス(4-((アミノフェニル)メチル)フェニル)-4-ブチルシクロヘキサン、3,5-ジアミノ安息香酸=5ξ-コレスタン-3-イル、環状カーボネート基を側鎖に有するジアミン、(メタ)アクリロイル基を側鎖に有するジアミン、下記式(E-1)
で表される化合物等の側鎖型ジアミン:
ポリアミック酸は、テトラカルボン酸二無水物とジアミン化合物とを、必要に応じて分子量調整剤(例えば、酸一無水物やモノアミン等)とともに反応させることにより得ることができる。ポリアミック酸の合成反応に供されるテトラカルボン酸二無水物及びジアミン化合物の使用割合は、ジアミン化合物のアミノ基1当量に対して、テトラカルボン酸二無水物の酸無水物基が0.2~2当量となる割合が好ましい。
ポリアミック酸エステルは、例えば、[I]上記合成反応により得られたポリアミック酸とエステル化剤とを反応させる方法、[II]テトラカルボン酸ジエステルとジアミン化合物とを反応させる方法、[III]テトラカルボン酸ジエステルジハロゲン化物とジアミン化合物とを反応させる方法、などによって得ることができる。液晶配向剤に含有させるポリアミック酸エステルは、アミック酸エステル構造のみを有していてもよく、アミック酸構造とアミック酸エステル構造とが併存する部分エステル化物であってもよい。
ポリイミドは、例えば上記の如くして合成されたポリアミック酸を脱水閉環してイミド化することにより得ることができる。環状シロキサン化合物[A]との架橋反応を十分に行わせる観点から、ポリイミドは、イミド化率が20~99%であることが好ましく、30~90%であることがより好ましい。イミド化率は、ポリイミドのアミック酸構造の数とイミド環構造の数との合計に対するイミド環構造の数の占める割合を百分率で表したものである。なお、イミド環の一部がイソイミド環であってもよい。
重合性不飽和結合を有するモノマーに由来する構造単位を有する重合体(以下、「重合体[Pm]」ともいう。)としては、例えば、重合性不飽和結合を有するモノマーとして(メタ)アクリル化合物、マレイミド化合物及びスチレン化合物のうち1種以上を用いて得られる重合体(ポリ(メタ)アクリレート、スチレン-マレイミド系共重合体、ポリスチレン、ポリマレイミド)等が挙げられる。配向性基を導入しやすい点、及び得られる液晶素子の信頼性がより良好である点で、重合体[Pm]は、好ましくは、ポリ(メタ)アクリレート及びスチレン-マレイミド系共重合体よりなる群から選ばれる少なくとも一種である。重合体[Pm]がスチレン-マレイミド系共重合体である場合、当該共重合体は、スチレン化合物及びマレイミド化合物とは異なるモノマー(例えば(メタ)アクリル化合物等)に由来する構造単位を更に有していてもよい。
N-メチルマレイミド、N-シクロヘキシルマレイミド、N-フェニルマレイミド、4-(2,5-ジオキソ-3-ピロリン-1-イル)安息香酸、N-(4-グリシジルオキシフェニル)マレイミド、N-グリシジルマレイミド、3-マレイミド安息香酸、3-マレイミドプロピオン酸、3-(2,5-ジオキソ-3-ピロリン-1-イル)安息香酸、4-(2,5-ジオキソ-3-ピロリン-1-イル)安息香酸メチル等のマレイミド化合物、などが挙げられる。
(I)第1の重合体及び第2の重合体が、ポリアミック酸、ポリアミック酸エステル及びポリイミドよりなる群から選ばれる重合体である態様。
(II)第1の重合体及び第2の重合体のうち一方が、ポリアミック酸、ポリアミック酸エステル及びポリイミドよりなる群から選ばれる一種の重合体であり、他方が重合体[Pm]である態様。
(III)第1の重合体及び第2の重合体が重合体[Pm]である態様。
環状シロキサン化合物[A]は、シロキサン結合(Si-O結合)による環状骨格を分子内に1個有する環式化合物であり、架橋性基を有する。架橋性基としては、他の基と共有結合して架橋構造を形成可能な基であれば特に限定されないが、例えばオキシラニル基、オキセタニル基、(メタ)アクリロイル基、アリル基、ビニルフェニル基、環状カーボネート基、メチロール基、アミノ基等が挙げられる。架橋性基としては、液晶配向剤の保存安定性を高くできる点で、好ましくはオキシラニル基、オキセタニル基及び(メタ)アクリロイル基よりなる群から選ばれる少なくとも一種であり、オキシラニル基が特に好ましい。なお、本明細書において「(メタ)アクリロイル」は、「アクリロイル」及び「メタクリロイル」を含む意味である。
R1~R6は、液晶配向剤中における環状シロキサン化合物[A]の分散性をより良好にできる点、並びに重合体成分との相溶性及び溶剤に対する溶解性をより良好にできる点で、炭素数1~20の1価の有機基であることが好ましく、炭素数1~20の1価の炭化水素基、1価の基Q1、1価の基Q2又は1価の基Q3であることがより好ましい。R1~R6の炭素数は、好ましくは1~15、より好ましくは1~10である。
*1-R7-X1 …(2)
(式(2)中、R7は、鎖状構造を有する2価の基であり、X1は架橋性基を有する1価の基である。「*1」は、ケイ素原子との結合手であることを表す。)
X1は、オキシラニル基、オキセタニル基、(メタ)アクリロイル基、アリル基、ビニルフェニル基、環状カーボネート基、メチロール基又はアミノ基を有する1価の基であることが好ましく、液晶配向剤の保存安定性の観点から、オキシラニル基、オキセタニル基又は(メタ)アクリロイル基を有する1価の基であることがより好ましく、エポキシ基(オキシラニル基又はオキセタニル基)を有する1価の基であることが特に好ましい。エポキシ基を有する1価の基としては、例えばエポキシ基、グリシジルオキシ基、エポキシシクロヘキシル基等が挙げられる。
nは、液晶配向剤中における環状シロキサン化合物[A]の分散性、重合体成分との相溶性、及び材料の入手容易性の観点から、1~10であることが好ましく、1~6であることがさらに好ましく、1~4であることが特に好ましい。
本開示の液晶配向剤は、必要に応じて、重合体成分及び環状シロキサン化合物[A]以外のその他の化合物を含有していてもよい。その具体例としては、例えば、エポキシ化合物(例えば、N,N,N’,N’-テトラグリシジル-m-キシリレンジアミン、1,3-ビス(N,N-ジグリシジルアミノメチル)シクロヘキサン、N,N,N’,N’-テトラグリシジル-4,4’-ジアミノジフェニルメタン、N,N-ジグリシジル-アミノメチルシクロヘキサン、1,6-ヘキサンジオールジ(メタ)アクリレート、ペンタエリスリトールトリ(メタ)アクリレート等)、官能性シラン化合物(例えば、3-アミノプロピルトリメトキシシラン、N-(2-アミノエチル)-3-アミノプロピルトリメトキシシラン等)、酸化防止剤、金属キレート化合物、硬化促進剤、界面活性剤、充填剤、分散剤、光増感剤等が挙げられる。その他の化合物の配合割合は、本開示の効果を損なわない範囲内において各化合物に応じて適宜選択することができる。
なお、架橋剤として環状シロキサン化合物[A]とは異なる化合物を併用する場合、当該化合物の含有割合は、液晶配向剤中に含有される環状シロキサン化合物[A]の合計量に対して、5質量%以下とすることが好ましく、1質量%以下とすることがより好ましい。
本開示の液晶配向剤は、重合体成分、環状シロキサン化合物[A]、及び必要に応じて任意に配合される成分が、好ましくは有機溶媒に溶解された溶液状の組成物として調製される。当該有機溶媒としては、例えば非プロトン性極性溶媒、フェノール系溶媒、アルコール、ケトン、エステル、エーテル、ハロゲン化炭化水素、炭化水素等が挙げられる。溶剤成分は、これらの1種でもよく、2種以上の混合溶媒であってもよい。
溶剤の具体例としては、第1溶剤として、例えばN-メチル-2-ピロリドン、γ-ブチロラクトン、γ-ブチロラクタム、N,N-ジメチルホルムアミド、N,N-ジメチルアセトアミド、4-ヒドロキシ-4-メチル-2-ペンタノン、ジイソブチルケトン、エチレンカーボネート、プロピレンカーボネート、N-エチル-2-ピロリドン、N-(n-ペンチル)-2-ピロリドン、N-(t-ブチル)-2-ピロリドン、N-メトキシプロピル-2-ピロリドン、1,3-ジメチル-2-イミダゾリジノン、3-ブトキシ-N,N-ジメチルプロパンアミド、3-メトキシ-N,N-ジメチルプロパンアミド等を;
第2溶剤として、例えばエチレングリコールモノブチルエーテル(ブチルセロソルブ)、エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノプロピルエーテル、ダイアセトンアルコール、ジエチレングリコールジメチルエーテル、ジエチレングリコールジエチルエーテル、ジエチレングリコールメチルエチルエーテル、プロピレングリコールモノメチルエーテル、プロピレングリコールモノメチルエーテルアセテート、3-メトキシ-1-ブタノール、シクロペンタノン、乳酸ブチル、酢酸ブチル、メチルメトキシプロピオネ-ト、エチルエトキシプロピオネ-ト、イソアミルプロピオネート、イソアミルイソブチレート、プロピレングリコールジアセテート、ジプロピレングリコールモノメチルエーテル、プロピレングリコールモノブチルエーテル、ジイソペンチルエーテル等を、それぞれ挙げることができる。なお、溶剤は、これらの1種単独でもよいが、第1溶剤と第2溶剤との混合溶剤であることが好ましい。
本開示の液晶配向膜は、上記のように調製された液晶配向剤により形成される。また、本開示の液晶素子は、上記で説明した液晶配向剤を用いて形成された液晶配向膜を具備する。液晶素子における液晶の動作モードは特に限定されず、例えばTN型、STN型、VA型(VA-MVA型、VA-PVA型などを含む。)、IPS(In-Plane Switching)型、FFS(Fringe Field Switching)型、OCB(Optically Compensated Bend)型、PSA型(Polymer Sustained Alignment)など種々のモードに適用することができる。液晶素子は、例えば以下の工程1~工程3を含む方法により製造することができる。工程1は、所望の動作モードによって使用基板が異なる。工程2及び工程3は各動作モード共通である。
先ず、一対の基板における各基板面に液晶配向剤を塗布し、好ましくは塗布面を加熱することにより基板上に塗膜を形成する。基板としては、例えばフロートガラス、ソーダガラスなどのガラス;ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリエーテルスルホン、ポリカーボネート、ポリ(脂環式オレフィン)などのプラスチックからなる透明基板を用いることができる。基板の一方の面に設けられる透明導電膜としては、酸化スズ(SnO2)からなるNESA膜(米国PPG社登録商標)、酸化インジウム-酸化スズ(In2O3-SnO2)からなるITO膜などを用いることができる。TN型、STN型又はVA型の液晶素子を製造する場合には、パターニングされた透明導電膜が設けられている基板二枚を用いる。一方、IPS型又はFFS型の液晶素子を製造する場合には、櫛歯型にパターニングされた電極が設けられている基板と、電極が設けられていない対向基板とを用いる。基板への液晶配向剤の塗布は、電極形成面上に、好ましくはオフセット印刷法、フレキソ印刷法、スピンコート法、ロールコーター法又はインクジェット印刷法により行う。
TN型、STN型、IPS型又はFFS型の液晶素子を製造する場合、上記工程1で形成した塗膜に液晶配向能を付与する処理(配向処理)を実施する。これにより、液晶分子の配向能が塗膜に付与されて液晶配向膜となる。配向処理としては、基板上に形成した塗膜を例えばナイロン、レーヨン、コットンなどの繊維からなる布を巻き付けたロールで一定方向に擦るラビング処理や、基板上に形成した塗膜に光照射を行って塗膜に液晶配向能を付与して光配向膜とする光配向処理等を用いることができる。一方、垂直配向(VA)型の液晶素子を製造する場合には、上記工程1で形成した塗膜をそのまま液晶配向膜として使用することができるが、液晶配向能を更に高めるために、該塗膜に対し配向処理を施すとよい。垂直配向型の液晶素子に好適な液晶配向膜は、PSA型の液晶素子にも好適に用いることができる。
上記のようにして液晶配向膜が形成された基板を2枚準備し、2枚の基板間に液晶配向膜に隣接して液晶が配置されるように液晶セルを製造する。液晶セルを製造するには、例えば、液晶配向膜が対向するように間隙を介して2枚の基板を対向配置し、2枚の基板の周辺部をシール剤により貼り合わせ、基板表面とシール剤で囲まれたセルギャップ内に液晶を注入充填し注入孔を封止する方法、ODF方式による方法等が挙げられる。シール剤としては、例えば硬化剤及びスペーサーとしての酸化アルミニウム球を含有するエポキシ樹脂等を用いることができる。液晶としては、ネマチック液晶及びスメクチック液晶を挙げることができ、その中でもネマチック液晶が好ましい。PSAモードでは、液晶セルの構築後に、一対の基板の有する導電膜間に電圧を印加した状態で液晶セルに光照射する処理を行う。
以下の例において、重合体の溶液粘度、重量平均分子量(Mw)、数平均分子量(Mn)、分子量分布(Mw/Mn)、イミド化率及びエポキシ当量は以下の方法により測定した。
<重合体の溶液粘度>
重合体の溶液粘度は、E型粘度計を用いて25℃において測定した。
<重量平均分子量、数平均分子量及び分子量分布>
ゲルパーミエーションクロマトグラフィー(GPC)により、下記条件でMw及びMnを測定した。分子量分布(Mw/Mn)は、得られたMw及びMnより算出した。
装置:昭和電工(株)の「GPC-101」
GPCカラム:(株)島津ジーエルシー製の「GPC-KF-801」、「GPC-KF-802」、「GPC-KF-803」及び「GPC-KF-804」を結合
移動相:テトラヒドロフラン(THF)
カラム温度:40℃
流速:1.0mL/分
試料濃度:1.0質量%
試料注入量:100μL
検出器:示差屈折計
標準物質:単分散ポリスチレン
<重合体のイミド化率>
ポリイミドを含有する溶液を純水に投入し、得られた沈殿を室温で十分に減圧乾燥した後、重水素化ジメチルスルホキシドに溶解し、テトラメチルシランを基準物質として室温で1H-NMRを測定した。得られた1H-NMRスペクトルから、下記数式(E-1)を用いてイミド化率を求めた。
イミド化率(%)=(1-A1/A2×α)×100 …(E-1)
(数式(E-1)中、A1は化学シフト10ppm付近に現れるNH基のプロトン由来のピーク面積であり、A2はその他のプロトン由来のピーク面積であり、αは重合体の前駆体(ポリアミック酸)におけるNH基のプロトン1個に対するその他のプロトンの個数割合である。)
<エポキシ当量>
エポキシ当量は、JIS C 2105に記載の塩酸-メチルエチルケトン法により測定した。
[合成例2-1:ポリイミドの合成]
テトラカルボン酸無水物として2,3,5-トリカルボキシシクロペンチル酢酸二無水物77g(0.34モル)、並びにジアミンとしてp-フェニレンジアミン19g(0.18モル)及び3,5-ジアミノ安息香酸27g(0.18モル)をN-メチル-2-ピロリドン(NMP)1,260gに溶解し、室温で6時間反応させることにより、ポリアミック酸を含有する溶液を得た。得られたポリアミック酸溶液を少量分取し、減圧にて濃縮することにより濃度10質量%の溶液として測定した溶液粘度は80mPa・sであった。 次いで、得られたポリアミック酸溶液にNMP600gを追加し、ピリジン136g及び無水酢酸105gを添加して110℃で4時間脱水閉環反応を行った。脱水閉環反応後、系内の溶媒を新たなγ-ブチロラクトンで溶媒置換し、さらに濃縮することにより、イミド化率約85%のポリイミドである重合体(PI-1)を20質量%含有する溶液600gを得た。この溶液を少量分取し、γ-ブチロラクトンを加えて濃度6.0質量%の溶液として測定した溶液粘度は22mPa・sであった。
テトラカルボン酸二無水物として1,2,3,4-シクロブタンテトラカルボン酸二無水物13.8g(0.070mol)、ジアミンとして2,2’-ジメチル-4,4’-ジアミノビフェニル16.3g(0.0769mol)をNMP170gに溶解し、25℃で3時間反応を行うことにより、ポリアミック酸(これを「重合体(PA-1)」とする。)を10質量%含有する溶液を得た。
窒素下、100mL二口フラスコに、重合モノマーとして、化合物(MI-1)5.00g(8.6mmol)、4-ビニル安息香酸0.64g(4.3mmol)、4-(2,5-ジオキソ-3-ピロリン-1-イル)安息香酸2.82g(13.0mmol)、及び4-(グリシジルオキシメチル)スチレン3.29g(17.2mmol)、ラジカル重合開始剤として2,2’-アゾビス(2,4-ジメチルバレロニトリル)0.31g(1.3mmol)、連鎖移動剤として2,4-ジフェニル-4-メチル-1-ペンテン0.52g(2.2mmol)、並びに溶媒としてテトラヒドロフラン25mlを加え、70℃で5時間重合した。n-ヘキサンに再沈殿した後、沈殿物を濾過し、室温で8時間真空乾燥することにより、スチレン-マレイミド系共重合体である重合体(StMI-A)を得た。GPCによるポリスチレン換算で測定される重量平均分子量Mwは30000、分子量分布Mw/Mnは2であった。
合成例2-3において、重合モノマーとして化合物(MI-1)に代えて化合物(MI-2)を用いた以外は合成例2-3と同様に重合を行った。n-ヘキサンに再沈殿した後、沈殿物を濾過し、室温で8時間真空乾燥することにより、スチレン-マレイミド系共重合体である重合体(StMI-B)を得た。GPCによるポリスチレン換算で測定される重量平均分子量Mwは25000、分子量分布Mw/Mnは2であった。
撹拌機、温度計、滴下漏斗及び還流冷却管を備えた反応容器に、2-(3,4-エポキシシクロヘキシル)エチルトリメトキシシラン100.0g、メチルイソブチルケトン500g、及びトリエチルアミン10.0gを仕込み、室温で混合した。ここに脱イオン水100gを滴下漏斗から30分かけて滴下した後、還流下で混合しつつ、80℃において6時間反応を行った。反応終了後、有機層を取り出し、これを0.2質量%硝酸アンモニウム水溶液により洗浄後の水が中性になるまで洗浄した後、減圧下で溶媒及び水を留去することにより、エポキシ基含有ポリオルガノシロキサンを粘調な透明液体として得た。このエポキシ基含有ポリオルガノシロキサン(これを「ポリオルガノシロキサン(PS-1)」とする。)のエポキシ当量を測定したところ186g/当量であった。
[実施例1]
1.液晶配向剤(AL-1)の調製
上記合成例2-1で得た重合体(PI-1)100質量部を含む溶液に、上記合成例2-3で得た重合体(StMI-A)10質量部、化合物(A-1-1)(商品名「KR-470」、信越シリコーン社製)2質量部、並びに溶剤としてNMP及びブチルセロソルブ(BC)を加え、溶剤組成がNMP/BC=50/50(質量比)、固形分濃度が4.0質量%の溶液とした。この溶液を孔径1μmのフィルターで濾過することにより液晶配向剤(AL-1)を調製した。
ITO膜からなる透明電極付きガラス基板の透明電極面上に、上記で調製した液晶配向剤(AL-1)を、スピンナーを用いて塗布し、80℃のホットプレートで1分間プレベークを行った。その後、庫内を窒素置換したオーブン中、230℃で1時間加熱して膜厚0.1μmの塗膜を形成した。次いで、この塗膜表面に、Hg-Xeランプ及びグランテーラープリズムを用いて、313nmの輝線を含む偏光紫外線1,000J/m2を、基板法線に対し40°傾いた方向から照射して、塗膜に液晶配向能を付与した。同じ操作を繰り返して、液晶配向膜を有する基板を一対(2枚)作成した。
液晶配向膜が形成された一対の基板のうち一方の基板における液晶配向膜を有する面の外周に、直径3.5μmの酸化アルミニウム球入りエポキシ樹脂接着剤をスクリーン印刷により塗布した。続いて、一対の基板の液晶配向膜面を対向させ、各基板の紫外線の光軸の基板面への投影方向が逆平行となるように圧着し、150℃で1時間かけて接着剤を熱硬化させた。次いで、液晶注入口より基板間の間隙にネガ型液晶(メルク社製、MLC-6608)を充填した後、エポキシ系接着剤で液晶注入口を封止した。さらに、液晶注入時の流動配向を除くために、これを130℃で加熱してから室温まで徐冷し、液晶セルを得た。次に、基板の外側両面に、偏光板を、その偏光方向が互いに直交し、かつ、液晶配向膜の紫外線の光軸の基板面への射影方向と45°の角度をなすように貼り合わせることにより光垂直型液晶表示素子を製造した。
上記の操作を繰り返し、液晶表示素子を複数個製造し、以下の耐熱性及び耐光性の評価を行った。なお、耐熱性及び耐光性の評価は、それぞれ別個の液晶表示素子を使用して行った。
[耐熱性の評価]
上記で製造した光垂直型液晶表示素子に、60℃において5Vの電圧を60マイクロ秒の印加時間、167ミリ秒のスパンで印加した後、印加解除から167ミリ秒後の電圧保持率を測定し、これを初期電圧保持率Arf[%]とした。次いで、この液晶セルを100℃オーブン内に1,000時間静置して熱ストレスを与えた後、再度、同じ条件で電圧保持率を測定し、これを熱ストレス後電圧保持率Atm[%]とした。初期電圧保持率Arfに対する熱ストレス後電圧保持率Atmの低下量α[%](α=Arf-Atm)を算出し、低下量αにより液晶表示素子の耐熱性を評価した。この低下量αが1%以下であった場合を耐熱性「極めて良好(◎)」、低下量αが1%を超えて2%以下であった場合を耐熱性「良好(○)」、低下量αが2%を超えて3%以下であった場合を耐熱性「可(△)」、低下量αが3%を超えた場合を耐熱性「不良(×)」と評価した。その結果、この実施例では耐熱性は「極めて良好(◎)」の評価であった。なお、電圧保持率の測定装置には(株)東陽テクニカ製VHR-1を使用した。
上記で製造した光垂直型液晶表示素子につき、耐熱性の評価と同様の条件で電圧保持率を測定し、これを初期電圧保持率Arf[%]とした。次いで、液晶表示素子を0ワット型白色蛍光灯下5cmの距離に静置し、1,000時間光を照射して光ストレスを与えた後、再度、同じ条件で電圧保持率を測定し、これを光ストレス後電圧保持率Agt[%]とした。初期電圧保持率Arfに対する光ストレス後電圧保持率Agtの低下量β[%](β=Arf-Agt)を算出し、低下量βにより液晶表示素子の耐光性を評価した。この低下量βが1%以下であった場合を耐光性「極めて良好(◎)」、低下量βが1%を超えて2%以下であった場合を耐光性「良好(○)」、低下量βが2%を超えて3%以下であった場合を耐光性「可(△)」、低下量βが3%を超えた場合を耐光性「不良(×)」と評価した。その結果、この実施例では耐光性は「極めて良好(◎)」の評価であった。
配合組成を下記表1~表3に示すとおり変更した以外は実施例1と同じ溶剤組成及び固形分濃度で液晶配向剤を調製した。また、それぞれの液晶配向剤を用いて実施例1と同様にして光垂直型液晶表示素子を製造し、各種評価を行った。それらの結果を下記表1~表3に示した。
1.液晶配向剤(AL-10)の調製
使用する重合体を、上記合成例2-2で得た重合体(PA-1)100質量部を含む溶液、及び上記合成例2-4で得た重合体(StMI-B)5質量部に変更した以外は上記実施例1と同じ溶媒組成及び固形分濃度で液晶配向剤(AL-10)を調製した。
ネマチック液晶(メルク社製、MLC-6608)10gに対し、上記式(L1-1) で表される液晶性化合物を5質量%、及び上記式(L2-1)で表される光重合性化合物 を0.3質量%添加して混合することにより液晶組成物LC1を得た。
上記で調製した液晶配向剤(AL-10)を、ITO電極からなる導電膜をそれぞれ有するガラス基板2枚の各電極面上に、液晶配向膜印刷機(日本写真印刷(株)製)を用いて塗布し、80℃のホットプレート上で2分間加熱(プレベーク)して溶媒を除去した後、230℃のホットプレート上で10分間加熱(ポストベーク)して、平均膜厚0.06μmの塗膜を形成した。これら塗膜につき、超純水中で1分間超音波洗浄を行った後、100℃クリーンオーブン中で10分間乾燥することにより、液晶配向膜を有する基板を一対(2枚)得た。なお、使用した電極のパターンは、PSAモードにおける電極パターンと同種のパターンである。
次いで、上記一対の基板のうち一方の基板の液晶配向膜を有する面の外縁に、直径5.5μmの酸化アルミニウム球入りエポキシ樹脂接着剤を塗布した後、液晶配向膜面が相対するように重ね合わせて圧着し、接着剤を硬化した。次いで、液晶注入口より一対の基板間に、上記で調製した液晶組成物LC1を充填した後、アクリル系光硬化接着剤で液晶注入口を封止することにより、液晶セルを製造した。その後、液晶セルの導電膜間に周波数60Hzの交流10Vを印加し、液晶が駆動している状態で、光源にメタルハライドランプを使用した紫外線照射装置を用いて、100,000J/m2の照射量にて紫外線を照射した。なお、この照射量は、波長365nm基準で計測される光量計を用いて測定した値である。その後、基板の外側両面に、偏光板を、その偏光方向が互いに直交し、かつ、液晶配向膜の紫外線の光軸の基板面への射影方向と45°の角度をなすように貼り合わせることによりPSA型液晶表示素子を製造した。
上記の操作を繰り返し、液晶表示素子を複数個製造し、実施例1と同様にして耐熱性及び耐光性の評価を行った。その結果、この実施例では、耐熱性及び耐光性のいずれも「極めて良好(◎)」の評価であった。
配合組成を下記表2及び表3に示すとおり変更した以外は実施例10と同じ溶剤組成及び固形分濃度で液晶配向剤を調製した。また、それぞれの液晶配向剤を用いて実施例10と同様にしてPSA型液晶表示素子を製造して、実施例1と同様にして各種評価を行った。それらの結果を下記表2及び表3に示した。
A-1-1:品名「KR-470」、信越シリコーン社製(上記式(A-1-1)で表される化合物)
A-2-1:品名「CS-697」、シグマアルドリッチ社製(上記式(A-2-1)で表される化合物)
A-3-1:品名「CS-783」、シグマアルドリッチ社製(上記式(A-3-1)で表される化合物)
C-1:品名「X-40-2669」、信越シリコーン社製(上記式(C-1)で表される化合物)
C-2:上記合成例2-5のポリオルガノシロキサン(PS-1)
C-3:N,N,N’,N’-テトラグリシジル-4,4’-ジアミノジフェニルメタン(上記式(C-3)で表される化合物)
これに対し、環状シロキサン化合物[A]を含有しない以外は実施例1~3、実施例10~13の液晶配向剤と同じ組成にした比較例4、5では、実施例に比べて、耐光性及び耐熱性の両方が劣っていた。
また、環状シロキサン化合物[A]に代えて、鎖状構造の多官能シロキサン化合物である化合物(C-1)を用いた比較例1では、実施例(実施例1~3)に比べて耐光性が劣り、実施例1,2に対しては耐熱性も劣っていた。環状シロキサン化合物[A]に代えてポリオルガノシロキサン(PS-1)を用いた比較例2、3では、実施例(実施例1~3、実施例10~13)に比べて耐光性及び耐熱性のいずれも劣っていた。
また、従来より使用されている架橋剤である化合物(C-3)を用いた比較例6についても、実施例に比べて耐光性及び耐熱性のいずれも劣っていた。
これらの結果から、架橋剤として環状シロキサン化合物[A]を用いることにより、耐熱性及び耐光性に優れた液晶素子を得ることができることが分かった。
Claims (8)
- 重合体成分と、架橋性基を有する環状シロキサン化合物[A]と、を含有する、液晶配向剤。
- 前記重合体成分は、ポリアミック酸、ポリアミック酸エステル、ポリイミド、及び重合性不飽和結合を有するモノマーに由来する構造単位を有する重合体よりなる群から選ばれる少なくとも一種である、請求項1又は2に記載の液晶配向剤。
- 前記重合体成分として2種以上の重合体を含有する、請求項1~3のいずれか一項に記載の液晶配向剤。
- 請求項1~4のいずれか一項に記載の液晶配向剤を用いて形成された液晶配向膜。
- 請求項5に記載の液晶配向膜を具備する液晶素子。
- 請求項1~4のいずれか一項に記載の液晶配向剤を一対の基板のそれぞれの基板面に塗布し、前記基板面に光を照射することにより光配向膜を形成する工程と、
前記液晶配向膜が形成された一対の基板を、液晶層を挟んで前記光配向膜が対向するように配置して液晶セルを構築する工程と、
を含む、液晶素子の製造方法。 - 請求項1~4のいずれか一項に記載の液晶配向剤を、導電膜を有する一対の基板のそれぞれの前記導電膜上に塗布して塗膜を形成する工程と、
前記塗膜が形成された一対の基板を、液晶層を挟んで前記塗膜が対向するように配置して液晶セルを構築する工程と、
前記導電膜間に電圧を印加した状態で前記液晶セルに光照射する工程と、
を含む、液晶素子の製造方法。
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CN112400135B (zh) | 2024-03-29 |
TWI791838B (zh) | 2023-02-11 |
TW202009265A (zh) | 2020-03-01 |
KR20210019096A (ko) | 2021-02-19 |
JPWO2020039695A1 (ja) | 2021-08-26 |
JP7310823B2 (ja) | 2023-07-19 |
CN112400135A (zh) | 2021-02-23 |
KR102527238B1 (ko) | 2023-04-27 |
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