CN106947498B

CN106947498B - Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal element, and method for producing liquid crystal alignment film and liquid crystal element

Info

Publication number: CN106947498B
Application number: CN201611120480.0A
Authority: CN
Inventors: 野口峻一
Original assignee: JSR Corp
Current assignee: JSR Corp
Priority date: 2016-01-07
Filing date: 2016-12-07
Publication date: 2022-02-11
Anticipated expiration: 2036-12-07
Also published as: CN106947498A; JP6828360B2; JP2017126060A; TWI711671B; TW201725242A; KR20170082969A

Abstract

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, a liquid crystal device, and a method for manufacturing a liquid crystal alignment film and a liquid crystal device. The liquid crystal aligning agent comprises polyorganosiloxane (C) with photo-aligning groups, and at least one of the polyorganosiloxane (C) and a polymer different from the polyorganosiloxane (C) contains a partial structure which shows liquid crystal property in a molecule. The liquid crystal aligning agent can obtain a liquid crystal element with excellent initial voltage holding ratio and light resistance.

Description

Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal element, and method for producing liquid crystal alignment film and liquid crystal element

Technical Field

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, a liquid crystal device, and a method for manufacturing a liquid crystal alignment film and a liquid crystal device.

Background

The liquid crystal element has a liquid crystal alignment film for aligning liquid crystal molecules. In recent years, with the expansion of use applications and use environments, requirements for display performance of liquid crystal panels have become more stringent. Therefore, various liquid crystal alignment films for improving various characteristics of liquid crystal panels have been studied (for example, see patent documents 1 and 2). Patent document 1 discloses forming a liquid crystal alignment film using a photo-alignment agent containing a polymer having photo-alignment ability and a polymer exhibiting liquid crystallinity, wherein the polymer having photo-alignment ability is at least one selected from the group consisting of polyamic acid, partially imidized polyamic acid, and polyimide. Patent document 2 discloses that a liquid crystal alignment film is formed by forming a coating film on a substrate using a side chain polymer exhibiting photosensitivity of liquid crystal properties, irradiating the coating film with polarized ultraviolet rays, and then heating the coating film.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent No. 5407394 publication

[ patent document 2] International publication No. 2013/081066

Disclosure of Invention

Problems to be solved by the invention

In the course of assuming use under severe environments such as continuous driving for a long time and use in a place where optical stress is present, along with the increase in the use of liquid crystal elements, it is important that the liquid crystal elements are less likely to suffer from deterioration caused by light (for example, a decrease in voltage holding ratio) during use and can withstand use under severe environments. In addition, in order to improve the display quality of the liquid crystal device, it is important that the initial voltage holding ratio is high, and in view of recent requirements for high performance of the liquid crystal device, a new technique for obtaining a liquid crystal device having a high initial voltage holding ratio and excellent light resistance is required.

The present invention has been made in view of the above problems, and an object thereof is to provide a liquid crystal aligning agent which can obtain a liquid crystal device having excellent initial voltage holding ratio and light resistance.

Means for solving the problems

The present inventors have made extensive studies to achieve the above-mentioned problems of the prior art, and have found that the above-mentioned problems can be solved by making the polymer component of the liquid crystal aligning agent have a specific composition, and have completed the present invention. Specifically, the following means are provided.

< 1 > A liquid crystal aligning agent comprising a polyorganosiloxane (C) having a photo-aligning group, wherein at least one of the polyorganosiloxane (C) and a polymer different from the polyorganosiloxane (C) has a partial structure exhibiting liquid crystallinity in the molecule.

< 2 > a liquid crystal alignment film formed using the liquid crystal aligning agent described in < 1 >.

< 3 > a liquid crystal cell comprising the liquid crystal alignment film described in said < 2 >.

< 4 > a method for producing a liquid crystal alignment film, comprising: a step of applying the liquid crystal aligning agent of < 1 > on a substrate to form a coating film, and a step of irradiating the surface of the substrate on which the liquid crystal aligning agent is applied with light to impart liquid crystal aligning ability to the coating film.

< 5 > a method for producing a liquid crystal cell, comprising: a step of forming a liquid crystal alignment film on each surface of the pair of substrates by the method < 4 >; a step of configuring a liquid crystal cell by disposing the pair of substrates with a liquid crystal layer containing a polymerizable monomer interposed therebetween such that the respective liquid crystal alignment films face each other; and a step of irradiating the liquid crystal cell with light.

< 6 > a method for producing a liquid crystal cell, comprising: a step of forming a liquid crystal alignment film on each surface of the pair of substrates by the method of < 4 > using a liquid crystal aligning agent containing a polymerizable monomer; a step of configuring a liquid crystal cell by disposing the pair of substrates with a liquid crystal layer interposed therebetween such that the respective liquid crystal alignment films face each other; and a step of irradiating the liquid crystal cell with light.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the liquid crystal aligning agent disclosed by the invention, a liquid crystal element with high initial voltage holding ratio and excellent light resistance can be obtained. Further, since the liquid crystal aligning agent of the present disclosure can be used for manufacturing a liquid crystal alignment film by a photo-alignment method, it is superior to the conventional rubbing method in that it can suppress the occurrence of display defects or the reduction of yield due to the generation of dust or static electricity, and can uniformly impart liquid crystal alignment capability to an organic thin film formed on a substrate.

Detailed Description

The disclosed liquid crystal aligning agent contains a polyorganosiloxane (C) having a photo-aligning group. Further, a polymer having a partial structure exhibiting liquid crystallinity is contained as at least one of the polyorganosiloxane (C) and a polymer different therefrom.

The partial structure exhibiting liquid crystallinity may be contained in the polyorganosiloxane (C), may be contained in a polymer different from the polyorganosiloxane (C), or may be contained in both of the polymers. From the viewpoint of the initial voltage holding ratio and light resistance of the liquid crystal device, the partial structure exhibiting liquid crystallinity is preferably contained in a polymer different from the polyorganosiloxane (C). That is, the liquid crystal aligning agent of the present disclosure preferably contains a polymer (a) exhibiting liquid crystallinity in a predetermined temperature range and a polyorganosiloxane (C) having a photo-aligning group. Hereinafter, the polymer (A) and the polyorganosiloxane (C) will be described in detail, and other components optionally blended in the liquid crystal aligning agent of the present disclosure will be described as required.

< Polymer (A) >)

The structure of the polymer (a) is not particularly limited as long as it exhibits liquid crystallinity in a predetermined temperature range, and examples thereof include polymers having a rigid site (mesogen structure) as a partial structure exhibiting liquid crystallinity. Examples of the mesogen structure of the polymer (a) include a structure represented by the following formula (1).

[ solution 1]

(in the formula (1), Ar¹And Ar²Each independently being a substituted or unsubstituted phenylene or cyclohexylene group, X¹Is a single bond, -CO-, -COO-, -C ═ C-, -C ≡ C-, -N ═ N-, or-CONR¹-(R¹A hydrogen atom or a monovalent organic group). n is an integer of 1 to 3. When n is 2 or 3, Ar²、X¹Each independently having the definition. "﹡" means a bond key)

In the formula (1), X¹Preferably a single bond or-COO-. As R¹Examples of the monovalent organic group include: alkyl groups having 1 to 6 carbon atoms, protecting groups, and the like. Specific examples of the protecting group include: tertiary amineButoxycarbonyl, benzyloxycarbonyl, 1-dimethyl-2-haloethoxycarbonyl, allyloxycarbonyl, and the like.

Ar¹And Ar²The substituent of the cyclic moiety of (a) is preferably an alkyl group having 1 to 5 carbon atoms or a halogen atom, and more preferably a methyl group or a fluorine atom.

Preferable specific examples of the partial structure represented by the formula (1) include: 4-biphenyl, 4-dicyclohexyl, p-terphenyl, 4 '-biphenylene, 4' -bicyclohexyl, p-terphenylene, and groups represented by the following formulae (1-1) to (1-4), respectively, and groups having a methyl group or a fluorine atom in the ring portion of these groups, and the like.

[ solution 2]

(wherein "﹡" represents a bond)

The polymer (a) may have a mesogen structure in either of the main chain and the side chain of the polymer, but from the viewpoint of high effect of improving light resistance of a liquid crystal element, a side chain type liquid crystalline polymer having a mesogen structure in the side chain is preferable. In the present specification, the term "main chain" of a polymer means a "dry" portion of a chain including the longest atom in the polymer. The "dry" portion is allowed to contain a ring structure. Therefore, the phrase "having a mesogenic structure in the main chain of the polymer" means that the structure constitutes a part of the main chain. By "side chain" of a polymer is meant a moiety that branches from the "stem" of the polymer. The polymer (a) may have a mesogen structure only in the main chain of the polymer, may have a mesogen structure only in the side chain, or may have a mesogen structure in both the main chain and the side chain.

The type of the main skeleton of the polymer (a) is not particularly limited, but from the viewpoint of affinity with liquid crystal, mechanical strength, and the like, at least one selected from the group consisting of a polymer of a monomer having a polymerizable unsaturated bond (hereinafter, also referred to as "polymer (PAc)"), polyamic acid, polyimide, and polyamic acid ester is preferable, and from the viewpoint of making the voltage holding ratio and light resistance of the liquid crystal element more favorable, polymer (PAc) is more preferable.

■ Polymer (PAc)

The monomer used for polymerization of the polymer (PAc) is not particularly limited as long as it has a polymerizable unsaturated bond, and examples thereof include: a (meth) acrylic compound, a conjugated diene compound, an aromatic vinyl compound, a maleimide compound, and the like. The polymer (PAc) is preferably a polymer obtained by using a monomer containing a (meth) acrylic compound as a raw material, from the viewpoint of having a high effect of improving the light resistance of a liquid crystal element. When the polymer (PAc) is synthesized, the use ratio of the (meth) acrylic compound is preferably 50 mol% or more, more preferably 60 mol% or more, and still more preferably 70 mol% or more, based on the total amount of monomers used for synthesis. In the present specification, "(meth) acrylic acid" means acrylic acid and methacrylic acid.

The polymer (PAc) may have a partial structure exhibiting liquid crystallinity, and may have a functional group (hereinafter, referred to as a "photoreactive group") that induces light to cause a crosslinking reaction, an isomerization reaction, a photodimerization reaction, or a Fries rearrangement (Fries rearrangement) reaction. Examples of the photoreactive group include: a group containing (meth) acrylic acid having a (meth) acrylic acid or a derivative thereof as a basic skeleton, a group having a vinyl group (an alkenyl group, a styryl group, or the like), an ethynyl group, an epoxy group (an oxirane group, an oxetanyl group), a group containing a phenylbenzoate or a derivative thereof as a basic skeleton, a group containing an azobenzene or a derivative thereof as a basic skeleton, a group containing a cinnamic acid structure containing cinnamic acid or a derivative thereof as a basic skeleton, a group containing a chalcone or a derivative thereof as a basic skeleton, a group containing a benzophenone or a derivative thereof as a basic skeleton, a group containing a coumarin or a derivative thereof as a basic skeleton, or the like.

The polymer (PAc) can be obtained, for example, by polymerizing a monomer having a polymerizable unsaturated bond in the presence of a polymerization initiator. The monomer to be used preferably contains a compound having a polymerizable unsaturated bond and a partial structure exhibiting liquid crystallinity. Specific examples of the monomer having a polymerizable unsaturated bond and a partial structure exhibiting liquid crystallinity include compounds represented by the following formulae (2-1) to (2-5). These monomers may be used alone or in combination of two or more.

[ solution 3]

In (formulae (2-1) to (2-5), R²Is a hydrogen atom or a methyl group, R³Is C1-12 alkanediyl or divalent group obtained by substituting at least 1 methylene group of the alkanediyl with-O-, R⁴Is an alkyl group, alkoxy group or fluoroalkyl group having 1 to 20 carbon atoms or a fluorine atom)

Further, when the polymer (PAc) is synthesized, a compound having no partial structure exhibiting liquid crystallinity may be used in combination as the monomer having a polymerizable unsaturated bond. The proportion of the compound having no partial structure which exhibits liquid crystallinity to the total amount of monomers used for synthesis of the polymer (PAc) is preferably 50 mol% or less, more preferably 40 mol% or less.

As the polymerization initiator used for the polymerization, for example, there can be mentioned: azo compounds such as 2,2' -azobis (isobutyronitrile), 2' -azobis (2, 4-dimethylvaleronitrile), and 2,2' -azobis (4-methoxy-2, 4-dimethylvaleronitrile). The use ratio of the polymerization initiator is preferably set to 0.01 to 30 parts by mass with respect to 100 parts by mass of all the monomers used for the reaction. The polymerization is preferably carried out in an organic solvent. Examples of the organic solvent used for the reaction include: alcohols, ethers, ketones, amides, esters, hydrocarbon compounds, and the like, and specific examples thereof include: diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether acetate, tetrahydrofuran, and the like. The reaction temperature is preferably from 30 to 120 ℃ and the reaction time is preferably from 1 to 36 hours. The amount of the organic solvent (a) used is preferably such that the total amount of the monomers (b) used in the reaction is 0.1 to 60% by mass relative to the total amount (a + b) of the reaction solution.

The weight average molecular weight (Mw) of the polymer (PAc) in terms of polystyrene as measured by Gel Permeation Chromatography (GPC) is preferably 250 to 500,000, more preferably 500 to 100,000, and still more preferably 1,000 to 50,000. Further, the polymer (PAc) may be used singly or in combination of two or more.

■ Polyamic acid

The polyamic acid (hereinafter also referred to as "polyamic acid (a)") as the polymer (a) is not particularly limited as long as it exhibits liquid crystallinity, but one having a mesogenic structure in the main chain of the polymer can be preferably used. When such a polyamic acid is to be obtained, it can be obtained, for example, by using at least either one of tetracarboxylic dianhydride having a mesogen structure in the main chain and diamine compound having a mesogen structure in the main chain for polymerization of raw materials. As an example of the polyamic acid exhibiting liquid crystallinity, a polymer obtained by reacting a tetracarboxylic dianhydride having a terphenyl skeleton in the main chain with a diamine compound, specifically, a polymer having a partial structure represented by the following formula (3) can be cited.

[ solution 4]

(in the formula (3), R⁵Being a divalent organic radical)

In the formula (3), R⁵The divalent organic group (2) is a group remaining after removal of 2 primary amino groups from the diamine compound. From the viewpoint of imparting liquid crystallinity to polyamic acid, R⁵Preferably a linear alkanediyl group having 4 to 20 carbon atoms or a divalent group containing-O-between carbon-carbon bonds of the alkanediyl group.

The tetracarboxylic dianhydride used for the synthesis of the polyamic acid (a) may be only a tetracarboxylic dianhydride having a mesogen structure, but a tetracarboxylic dianhydride not having a mesogen structure may be used in combination. The tetracarboxylic dianhydride is not particularly limited, and a known tetracarboxylic dianhydride can be used. When a polyamic acid exhibiting liquid crystallinity is synthesized, the ratio of tetracarboxylic dianhydride having a mesogen structure is preferably 50 mol% or more, more preferably 70 mol% or more, relative to the total amount of tetracarboxylic dianhydrides used for the synthesis.

Examples of the diamine compound used for the synthesis of the polyamic acid (a) include: aliphatic diamines, alicyclic diamines, aromatic diamines, diaminoorganosiloxanes, and the like. Among these, aliphatic diamines are preferably used, and alkylene diamines such as 1, 4-diaminobutane, hexamethylenediamine, and octamethylenediamine are more preferred. When the polyamic acid (a) is synthesized, the use ratio of the alkylene diamine is preferably 50 mol% or more, more preferably 60 mol% or more, based on the total amount of the diamine compounds used for the synthesis.

The polyamic acid (a) can be obtained by reacting the tetracarboxylic dianhydride and the diamine compound as described above together with a molecular weight modifier if necessary. The ratio of the tetracarboxylic dianhydride and the diamine compound used in the synthesis reaction of the polyamic acid is preferably such that the acid anhydride group of the tetracarboxylic dianhydride is 0.2 to 2 equivalents relative to 1 equivalent of the amino group of the diamine compound. Examples of the molecular weight regulator include: acid monoanhydrides such as maleic anhydride and phthalic anhydride, monoamine compounds such as aniline, cyclohexylamine and n-butylamine, and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The use ratio of the molecular weight modifier is preferably 20 parts by mass or less with respect to 100 parts by mass of the total of the tetracarboxylic dianhydride and the diamine compound.

The synthesis reaction of the polyamic acid (a) is preferably carried out in an organic solvent. The reaction temperature in this case is preferably-20 ℃ to 150 ℃ and the reaction time is preferably 0.1 hour to 24 hours.

Examples of the organic solvent used for the reaction include: aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and the like. Particularly preferred organic solvents are those using one or more organic solvents selected from the group consisting of N-methyl-2-pyrrolidone, N-dimethylacetamide, N-dimethylformamide, dimethyl sulfoxide, γ -butyrolactone, tetramethylurea, hexamethylphosphoric triamide, m-cresol, xylenol, and halogenated phenol, or mixtures of one or more of these organic solvents and other organic solvents (e.g., butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount (a) of the organic solvent used is preferably such that the total amount (b) of the tetracarboxylic dianhydride and the diamine is 0.1 to 50% by mass relative to the total amount (a + b) of the reaction solution.

In this manner, a reaction solution in which the polyamic acid (a) is dissolved can be obtained. The reaction solution may be directly supplied to the preparation of the liquid crystal aligning agent, or may be supplied to the preparation of the liquid crystal aligning agent after the polyamic acid contained in the reaction solution is isolated.

■ Polyamic acid ester

The polyamic acid ester as the polymer (a) can be obtained, for example, by the following method: a method of reacting the polyamic acid (a) obtained by the synthesis reaction with an esterifying agent (e.g., an alcohol or the like); a method of reacting a tetracarboxylic acid diester with a diamine compound; a process for reacting a tetracarboxylic acid diester dihalide with a diamine compound. The polyamic acid ester obtained may have only the amic acid ester structure or may be a partially esterified product in which the amic acid structure and the amic acid ester structure coexist. The reaction solution obtained by dissolving the polyamic acid ester may be used as it is for the production of the liquid crystal aligning agent, or may be used for the production of the liquid crystal aligning agent after the polyamic acid ester contained in the reaction solution is isolated.

■ polyimide

The polyimide as the polymer (a) can be obtained by, for example, imidizing the polyamic acid (a) synthesized in the above-described manner by dehydrative ring closure. The polyimide may be a complete imide compound obtained by dehydration ring closure of the entire amic acid structure of the polyamic acid as a precursor thereof, or may be a partial imide compound obtained by dehydration ring closure of only a part of the amic acid structure and coexistence of the amic acid structure and the imide ring structure. The imidization ratio of the polyimide used for the reaction is preferably 20% to 99%, more preferably 30% to 90%. The imidization ratio is a ratio 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 expressed as a percentage.

The dehydration ring-closing of the polyamic acid is performed, for example, by the following method: dissolving polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring-closure catalyst to the solution, and optionally heating. As the dehydrating agent, for example, there can be used: anhydrides such as acetic anhydride, propionic anhydride and trifluoroacetic anhydride. The amount of the dehydrating agent to be used is preferably 0.01 to 20 moles based on 1 mole of the amic acid structure of the polyamic acid. As the dehydration ring-closing catalyst, for example, there can be used: tertiary amines such as pyridine, collidine, lutidine and triethylamine. The amount of the dehydration ring-closing catalyst to be used is preferably 0.01 to 10 mol based on 1 mol of the dehydrating agent to be used. Examples of the organic solvent used in the dehydration ring-closure reaction include organic solvents exemplified as organic solvents used in the synthesis of polyamic acid. The reaction temperature of the dehydration ring-closing reaction is preferably 0 ℃ to 180 ℃. The reaction time is preferably 1.0 to 120 hours. In this manner, a reaction solution containing polyimide can be obtained. The reaction solution may be directly used for the preparation of the liquid crystal aligning agent, or may be used for the preparation of the liquid crystal aligning agent after the polyimide is isolated.

When the solution is prepared in a concentration of 10% by mass, the solution viscosity of the polyamic acid, polyamic acid ester, and polyimide as the polymer (A) preferably has a solution viscosity of 10 mPas to 800 mPas, and more preferably has a solution viscosity of 15 mPas to 500 mPas. The solution viscosity (mPas) is a value measured at 25 ℃ with an E-type rotational viscometer for a 10 mass% polymer solution prepared using a good solvent for these polymers (e.g., γ -butyrolactone, N-methyl-2-pyrrolidone, etc.).

The weight average molecular weight (Mw) of the polyamic acid, polyamic acid ester, and polyimide, as measured by GPC, in terms of polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. The molecular weight distribution (Mw/Mn) represented by the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 15 or less, more preferably 10 or less.

The temperature range in which the polymer (a) exhibits liquid crystallinity (hereinafter also referred to as "liquid crystal temperature range") is not particularly limited, but from the viewpoint of sufficiently improving the alignment controllability and the alignment stability of the obtained liquid crystal alignment film, the liquid crystal temperature range is preferably in the range of 90 to 380 ℃, more preferably in the range of 100 to 350 ℃.

< polyorganosiloxane (C) >

The photo-alignment group of the polyorganosiloxane (C) is a functional group that imparts anisotropy to the film by a photo-isomerization reaction, a photo-dimerization reaction, a photo-decomposition reaction, or the like caused by light irradiation. The polyorganosiloxane (C) may have a photo-alignment group in either the main chain or the side chain, but it is preferable to use a polyorganosiloxane having a photo-alignment group in the side chain. Specific examples of the photo-alignment group of the polyorganosiloxane (C) include: the group containing azobenzene, the group containing cinnamic acid structure, the group containing chalcone, the group containing benzophenone, the group containing coumarin, etc. Among these, a group containing a cinnamic acid structure is preferable from the viewpoint of high photosensitivity and easy introduction into a side chain. Among them, the group containing a cinnamic acid structure of the polyorganosiloxane (C) is preferably at least one selected from the group consisting of a group represented by the following formula (cn-1) and a group represented by the following formula (cn-2).

[ solution 5]

(in the formula (cn-1), R¹¹Is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or a cyano group. R¹²Is phenylene, biphenylene, terphenylene or cyclohexylene, or a group in which at least a part of hydrogen atoms of these groups is substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms or a cyano group. A. the¹¹Is a single bond, an oxygen atom, a sulfur atom, an alkanediyl group having 1 to 3 carbon atoms, -CH ═ CH-, -NH-, or ﹡¹-COO-、﹡¹-OCO-、﹡¹-NH-CO-、﹡¹-CO-NH-、﹡¹-CH₂-O-or ﹡¹-O-CH₂-(“﹡¹"represents and R¹²The bond of (b). R¹³Is a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or a cyano group. a is 0 or 1, and b is an integer of 0 to 4. Wherein when b is 2 or more, a plurality of R¹³May be the same or different. "﹡" means a bond key)

[ solution 6]

(in the formula (cn-2), R¹⁴A monovalent organic group having 1 to 20 carbon atoms. R¹⁵Is a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or a cyano group. A. the¹²Is an oxygen atom, ﹡¹-COO-、﹡¹-OCO-、﹡¹-NH-CO-or ﹡¹-CO-NH-(“﹡¹"represents and R¹⁶The bond of (b). R¹⁶An alkanediyl group having 1 to 6 carbon atoms. c is 0 or 1, and d is an integer of 0 to 4. Wherein when d is 2 or more, a plurality of R¹⁵May be the same or different. "﹡" means a bond key)

As R¹⁴Examples of the monovalent organic group include: alkyl group having 1 to 3 carbon atoms, -R²¹-X²-R²²、-R²²(R²¹Is substituted or unsubstituted phenylene or cyclohexylene, R²²Is substituted or unsubstituted phenyl or cyclohexyl, X²Is a single bond, an oxygen atom, a sulfur atom, an alkanediyl group having 1 to 3 carbon atoms, -CH ═ CH-, -NH-, -COO-, -NH-CO-, or-CH₂-O-), and the like. As R²¹、R²²Examples of the substituent(s) include: halogen atom, alkyl group having 1 to 3 carbon atoms, alkoxy group having 1 to 3 carbon atoms, cyano group, etc.

The method for synthesizing the polyorganosiloxane (C) is not particularly limited. As an example, the following methods can be mentioned: if necessary, a hydrolyzable silane compound containing an epoxy group and another silane compound are hydrolyzed and condensed, and then a carboxylic acid having a photo-alignment group is reacted.

Examples of the epoxy group-containing silane compound include: 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane and the like. The other silane compound is not particularly limited as long as it is a compound having hydrolyzability, and examples thereof include: tetramethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, p-styryltrimethoxysilane, vinyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylpropylsuccinic anhydride, and the like. Further, one kind of the silane compound may be used alone, or two or more kinds may be used in combination.

The hydrolysis and condensation reaction is preferably carried out by reacting one or more silane compounds with water in the presence of an appropriate catalyst and an organic solvent. During the reaction, the proportion of water used is preferably 1 to 30 moles based on 1 mole of the silane compound (total amount). Examples of the catalyst to be used include: acids, alkali metal compounds, organic bases, titanium compounds, zirconium compounds, and the like. The amount of the catalyst used varies depending on the kind of the catalyst, reaction conditions such as temperature, and the like, and is, for example, 0.01 to 3 times by mol based on the total amount of the silane compound. Examples of the organic solvent used include hydrocarbons, ketones, esters, ethers, alcohols, and the like, and it is preferable to use an organic solvent which is not water-soluble or hardly water-soluble. The use ratio of the organic solvent is preferably 10 to 10,000 parts by mass with respect to 100 parts by mass of the total amount of the silane compounds used for the reaction. The reaction is preferably carried out by heating with an oil bath or the like. In this case, the heating temperature is preferably 130 ℃ or lower, and the heating time is preferably 0.5 to 12 hours. After the reaction is completed, the organic solvent layer separated and taken out from the reaction solution is dried by a drying agent as necessary, and then the solvent is removed, whereby an epoxy group-containing polyorganosiloxane can be obtained.

The reaction of the epoxy group-containing polyorganosiloxane with the carboxylic acid is preferably carried out in the presence of a catalyst and an organic solvent. The proportion of the carboxylic acid used is preferably 5 mol% or more, more preferably 10 to 80 mol% based on the epoxy group of the epoxy group-containing polyorganosiloxane. As the catalyst, for example, an organic base, a compound known as a so-called hardening accelerator that accelerates the reaction of an epoxy compound, or the like can be used. The proportion of the catalyst used is preferably 100 parts by weight or less based on 100 parts by weight of the epoxy group-containing polysiloxane. Preferred specific examples of the organic solvent to be used include: 2-butanone, 2-hexanone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, butyl acetate, and the like. The organic solvent is preferably used in a proportion such that the solid content concentration is 5 to 50 wt%. The reaction temperature in the reaction is preferably 0 ℃ to 200 ℃, and the reaction time is preferably 0.1 hour to 50 hours. After the reaction is completed, the organic solvent layer separated and taken out from the reaction solution is dried with a drying agent as necessary, and then the solvent is removed, whereby polyorganosiloxane (C) having photo-alignment groups can be obtained.

The method for synthesizing the polyorganosiloxane (C) is not limited to the hydrolysis and condensation reaction, and may be carried out, for example, by reacting a hydrolyzable silane compound in the presence of oxalic acid and an alcohol. In addition, when a polyorganosiloxane having a photo-alignment group in a side chain is to be obtained, a method using a hydrolyzable silane compound having a photo-alignment group for polymerization of a raw material may be employed.

The polyorganosiloxane (C) preferably has a weight average molecular weight, as measured by GPC, of 500 to 1,000,000, more preferably 1,000 to 100,000, and still more preferably 1,000 to 50,000 in terms of polystyrene. Further, the polyorganosiloxane (C) may be used alone or in combination of two or more.

The liquid crystal aligning agent of the present disclosure preferably contains at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide in the polymer component. The polymer may be the polymer (a) which exhibits liquid crystallinity in a predetermined temperature range, or may be a polymer which does not exhibit liquid crystallinity. In a preferred embodiment of the liquid crystal aligning agent of the present disclosure, the liquid crystal aligning agent further contains a non-liquid crystal polymer (hereinafter, also referred to as "polymer (B)") selected from at least one of the group consisting of polyamic acid, polyamic acid ester, and polyimide as a polymer component. The polymer (B) is preferably contained in order to improve the effect of improving the initial voltage holding ratio and the light resistance of the liquid crystal device.

The polyamic acid (hereinafter also referred to as "polyamic acid (B)") as the polymer (B) can be obtained by, for example, reacting tetracarboxylic dianhydride with a diamine compound. Specific examples of the tetracarboxylic dianhydride used for synthesis of the polyamic acid include aliphatic tetracarboxylic dianhydrides such as 1,2,3, 4-butanetetracarboxylic dianhydride, ethylenediaminetetraacetic dianhydride, and the like; examples of the alicyclic tetracarboxylic dianhydride include 1,2,3, 4-cyclobutanetetracarboxylic dianhydride, 1, 3-dimethyl-1, 2,3, 4-cyclobutanetetracarboxylic dianhydride, 2,3, 5-tricarboxycyclopentylacetic dianhydride, 5- (2, 5-dioxotetrahydrofuran-3-yl) -3a,4,5,9 b-tetrahydronaphtho [1,2-c ] furan-1, 3-dione, 5- (2, 5-dioxotetrahydrofuran-3-yl) -8-methyl-3 a,4,5,9 b-tetrahydronaphtho [1,2-c ] furan-1, 3-dione, 5- (2, 5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1, 2-dicarboxylic anhydride, 2,4,6, 8-tetracarboxylic bicyclo [3.3.0] octane-2: 4,6: 8-dianhydride, cyclohexanetetracarboxylic dianhydride, or the like; examples of the aromatic tetracarboxylic acid dianhydride include pyromellitic dianhydride, 4' - (hexafluoroisopropylidene) diphthalic anhydride, p-phenylene bis (trimellitic acid monoester anhydride), ethylene glycol bis (anhydrotrimellitate), 1, 3-propanediol bis (anhydrotrimellitate), and the like; in addition, tetracarboxylic dianhydrides described in Japanese patent application laid-open No. 2010-97188 can be used. Further, the tetracarboxylic dianhydride may be used singly or in combination of two or more.

Specific examples of the diamine compound used for the synthesis of the polyamic acid (B) include aliphatic diamines such as m-xylylenediamine, 1, 3-propylenediamine, and hexamethylenediamine; examples of the alicyclic diamine include 1, 4-diaminocyclohexane, 4' -methylenebis (cyclohexylamine), and the like; examples of the aromatic diamine include side chain diamines such as dodecyloxydiaminobenzene, octadecyloxydiaminobenzene, cholestanyloxydiaminobenzene, cholestenyloxydiaminobenzene, cholestyryl diaminobenzoate, lanostanyl diaminobenzoate, 3, 6-bis (4-aminobenzoyloxy) cholestane, 1-bis (4- ((aminophenyl) methyl) phenyl) -4-butylcyclohexane, 2, 5-diamino-N, N-diallylaniline, and compounds represented by the following formula (E-1):

[ solution 7]

(in the formula (E-1), X^IAnd X^III are each independently a single bond, -O-, -COO-or-OCO-, R^IIs C1-3 alkanediyl, R^IIIs a single bond or C1-3 alkanediyl, a is 0 or 1, b is an integer of 0-2, c is an integer of 1-20, and d is 0 or 1. Wherein a and b do not become 0 at the same time)

P-phenylenediamine, 4 '-diaminodiphenylmethane, 4-aminophenyl-4' -aminobenzoate, 4 '-diaminoazobenzene, 1, 5-bis (4-aminophenoxy) pentane, bis [2- (4-aminophenyl) ethyl ] hexanedioic acid, N-bis (4-aminophenyl) methylamine, 2, 6-diaminopyridine, 1, 4-bis- (4-aminophenyl) -piperazine, N' -bis (4-aminophenyl) -benzidine, 2 '-dimethyl-4, 4' -diaminobiphenyl, 2 '-bis (trifluoromethyl) -4,4' -diaminobiphenyl, diaminobenzoic acid, 4 '-diaminodiphenyl ether, N' -bis (4-aminophenyl) methylamine, N '-bis (4-aminophenyl) methylamine, 2, 6-diaminopyridine, 1, 4-bis (4-aminophenyl) -piperazine, N' -bis (4-aminophenyl) -benzidine, 2 '-dimethyl-4, 4' -diaminodiphenyl ether, 2, N '-diaminodiphenyl-bis (4-aminophenyl) piperazine, 2, N' -diaminodiphenyl, N, Main chain type diamines such as 2, 2-bis [4- (4-aminophenoxy) phenyl ] propane, 2-bis (4-aminophenyl) hexafluoropropane, 4' - (phenylenediisopropylidene) dianiline, 4- (4-aminophenoxycarbonyl) -1- (4-aminophenyl) piperidine, 4' - [4,4' -propane-1, 3-diylbis (piperidine-1, 4-diyl) ] diphenylamine and a diamine having a cinnamic acid structure; examples of the diaminoorganosiloxane include 1, 3-bis (3-aminopropyl) -tetramethyldisiloxane; in addition, diamines described in JP 2010-97188 can be used. Further, the diamine compound may be used singly or in combination of two or more.

The polyamic acid (B) can be obtained by reacting the tetracarboxylic dianhydride and the diamine compound as described above together with a molecular weight modifier if necessary. The molecular weight modifier, polymerization solvent, reaction conditions, and the like used in the reaction can be applied to the description of the polyamic acid (a).

Polyamic acid esters and polyimides as the polymer (B) can be obtained in the same manner as in the case of the polymer (a) except that, for example, polyamic acid (B) is used instead of polyamic acid (a). The polymer (A) is used for the solution viscosity, weight average molecular weight and number average molecular weight of the polymer (B).

The polymer component in the liquid crystal aligning agent of the present disclosure is preferably in any one of the following forms [1] to [4 ].

[1] Comprises a polymer (A) and a polyorganosiloxane (C) as polymer components, wherein the polymer (A) is in the form of a polymer (PAc).

[2] The polymer composition comprises a polymer (A) and a polyorganosiloxane (C) as polymer components, wherein the polymer (A) is in the form of at least one selected from the group consisting of polyamic acids, polyamic acid esters, and polyimides.

[3] Comprises a polymer (A), a polymer (B) and a polyorganosiloxane (C) as polymer components, wherein the polymer (A) is in the form of a polymer (PAc).

[4] The polymer composition comprises a polymer (A), a polymer (B) and a polyorganosiloxane (C) as polymer components, wherein the polymer (A) is in the form of at least one selected from the group consisting of polyamic acids, polyamic acid esters, and polyimides.

Among these forms, the following are more preferable from the viewpoint of the initial voltage holding ratio and the light resistance of the liquid crystal element [1] and [3], and the following is particularly preferable [3 ]. Further, the polymer (A) and the polymer (B) may be those which exhibit photosensitivity to exposure for developing anisotropy of the polyorganosiloxane (C) by light induction, or those which do not exhibit photosensitivity to the exposure. The liquid crystal element is preferably non-photosensitive from the viewpoint of initial voltage holding ratio and light resistance.

In the liquid crystal aligning agent of the present disclosure, the content ratio of the polymer (a) and the polyorganosiloxane (C) is preferably 1 to 80 parts by mass, more preferably 3 to 70 parts by mass, and even more preferably 5 to 60 parts by mass, relative to 100 parts by mass of the total of the polymer components contained in the liquid crystal aligning agent, from the viewpoint of sufficiently obtaining the effect of improving the initial voltage holding ratio and the light resistance of the liquid crystal device. The polyorganosiloxane (C) is preferably 1 to 99 parts by mass, more preferably 5 to 95 parts by mass, and still more preferably 10 to 90 parts by mass, based on 100 parts by mass of the total of the polymer components contained in the liquid crystal aligning agent. In addition, the ratio of the polymer (a) to the polyorganosiloxane (C) is preferably set as the polymer (a): polyorganosiloxane (C) ═ 5: 95-70: 30, more preferably 10: 90-60: 40.

when the polymer (B) is blended in the liquid crystal aligning agent of the present disclosure, the content ratio of the polymer (B) is preferably 1 to 95 parts by mass, more preferably 20 to 90 parts by mass, and still more preferably 40 to 80 parts by mass, based on 100 parts by mass of the total of the polymer components contained in the liquid crystal aligning agent.

The liquid crystal aligning agent of the present disclosure may contain the polymer (a) and the polyorganosiloxane (C) together with other components than the polymer (a) and the polyorganosiloxane (C). Examples of the other components other than the polymer (B) include: polymers other than the polymer (A), the polymer (B) and the polyorganosiloxane (C), compounds having at least one epoxy group in the molecule, functional silane compounds, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, and the like. The blending ratio of the other components may be appropriately selected depending on each compound within a range not impairing the effects of the present disclosure.

(solvent)

The liquid crystal aligning agent of the present disclosure is preferably prepared as a liquid composition in which the polymer component and other components used as necessary are dispersed or dissolved in an appropriate solvent. Examples of the organic solvent to be used include: n-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1, 2-dimethyl-2-imidazolidinone, gamma-butyrolactone, gamma-butyrolactam, N-dimethylformamide, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol N-propyl ether, ethylene glycol isopropyl ether, ethylene glycol N-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, ethylene glycol isopropyl ether, ethylene glycol N-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, ethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol dimethyl, Diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisoamyl ether, ethylene carbonate, propylene carbonate, and the like. These organic solvents may be used alone or in combination of two or more.

The solid content concentration in the liquid crystal aligning agent (the ratio of the total mass of the components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, and the like, but is preferably in the range of 1 to 10 mass%. That is, a liquid crystal alignment agent is applied to the surface of a substrate as described below, and preferably heated to form a coating film as a liquid crystal alignment film or a coating film to be a liquid crystal alignment film. In this case, when the solid content concentration is less than 1% by mass, the film thickness of the coating film becomes too small to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10 mass%, the film thickness of the coating film becomes too large to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent tends to increase and the coatability tends to decrease.

< liquid crystal element >

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, and can be applied to various modes such as a Twisted Nematic (TN) mode, a Super Twisted Nematic (STN) mode, a Vertical Alignment (including a Vertical Alignment (VA) -Multi-Domain Vertical Alignment (MVA) mode, a VA-Pattern Vertical Alignment (PVA) mode, and the like), an In-Plane Switching (IPS) mode, a Fringe Field Switching (FFS) mode, and an Optically Compensated Bend (OCB) mode. The liquid crystal element can be manufactured by a method including, for example, the following steps 1 to 3. In step 1, the substrate used differs depending on the desired operation mode. Step 2 and step 3 are common to each operation mode.

[ step 1: formation of coating film ]

First, a liquid crystal aligning agent is applied to a substrate, and then the applied surface is heated as necessary, thereby forming a coating film on the substrate. As the substrate, for example: float glass, soda glass, and the like; transparent substrates comprising plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly (alicyclic olefin). As the transparent conductive film provided on one surface of the substrate, a transparent conductive film containing tin oxide (SnO) can be used₂) The NESA film (registered trademark of PPG corporation, USA) contains indium oxide-tin oxide (In)₂O₃-SnO₂) Indium Tin Oxide (ITO) film, and the like. When manufacturing a TN type, STN type, or vertical alignment type liquid crystal element, two substrates provided with a patterned transparent conductive film are used. In the manufacture of a liquid crystal device of a lateral electric field type such as an IPS type or an FFS type, a substrate provided with an electrode including a transparent conductive film or a metal film patterned in a comb-tooth shape and a counter substrate provided with no electrode are used. As the metal film, for example, a film containing a metal such as chromium can be used. The coating on the substrate is preferably performed on the electrode-forming surface by a lithographic method, a spin coating method, a roll coater method, or an inkjet printing method.

After the liquid crystal aligning agent is applied, preheating (prebaking) is preferably performed in order to prevent sagging and the like of the applied liquid crystal aligning agent. The pre-baking temperature is preferably 30-200 ℃, and the pre-baking time is preferably 0.25-10 minutes. Thereafter, the solvent is completely removed, and a calcination (post-baking) step is performed for the purpose of thermal imidization of the amic acid structure present in the polymer, if necessary. In this case, the calcination temperature (post-baking temperature) is preferably 80 to 300 ℃ and the post-baking time is preferably 5 to 200 minutes. The film thickness of the film formed in this manner is preferably 0.001 to 1 μm.

[ step 2: orientation treatment ]

When a TN-type, STN-type, IPS-type, or FFS-type liquid crystal cell is manufactured, a treatment (alignment treatment) of imparting liquid crystal alignment ability to the coating film formed in the 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. As the orientation treatment, there can be mentioned: rubbing the coating film in a fixed direction with a roller wound with a cloth containing fibers such as nylon, rayon, and cotton, for example, to impart liquid crystal alignment ability to the coating film; and photo-alignment treatment for applying light to the surface of the substrate coated with the liquid crystal alignment agent to impart liquid crystal alignment ability to the coating film. The liquid crystal aligning agent of the present disclosure can be preferably applied with photo-alignment treatment from the viewpoint of imparting a sufficient liquid crystal alignment control force by light irradiation to the coating film, or from the viewpoint of suppressing the occurrence of display defects or the reduction in yield due to the generation of dust or static electricity, or from the viewpoint of uniformly imparting liquid crystal alignment ability to the organic thin film formed on the substrate. When a vertical alignment type liquid crystal element is produced, the coating film formed in the step 1 may be used as it is as a liquid crystal alignment film, but the coating film may be subjected to an alignment treatment.

In the photo-alignment treatment, ultraviolet rays and visible rays including light having a wavelength of 150 to 800nm, for example, can be used as the light for irradiating the coating film. Ultraviolet rays containing light having a wavelength of 200nm to 400nm are preferable. When the irradiation light is linearly polarized light or partially polarized light, the substrate surface may be irradiated from a vertical direction, may be irradiated from an oblique direction, or may be irradiated by a combination of both. When unpolarized radiation is irradiated, the irradiation direction is set to an oblique direction.

As the light source used, for example, there can be used: low-pressure mercury lamp, high-pressure mercury lamp, deuterium lamp, metal halide lamp, argon resonance lamp, xenon lampLamps, excimer lasers, and the like. Ultraviolet rays in a preferred wavelength range can be obtained by a method of using a light source in combination with, for example, a filter, a diffraction grating, or the like. The dose of radiation is preferably 200J/m²～50,000J/m²More preferably 400J/m²～20,000J/m². The coating film after the post-baking step may be irradiated with light for imparting alignment ability, the coating film after the pre-baking step and before the post-baking step may be irradiated with light for imparting alignment ability, or the coating film may be irradiated with light for imparting alignment ability during heating in at least either of the pre-baking step and the post-baking step.

[ step 3: construction of liquid Crystal cell

A liquid crystal cell was produced by preparing 2 substrates on which liquid crystal alignment films were formed in the above-described manner, and disposing liquid crystal between the 2 substrates disposed in opposition to each other. Specifically, there may be mentioned: a method of bonding the peripheral portions of the pair of substrates with a sealant, injecting a filling liquid crystal into a cell gap defined by the surfaces of the substrates and the sealant, and then sealing the injection hole; a method (One Drop Fill (ODF) method) in which a sealant is applied to a peripheral portion of One substrate on the liquid crystal alignment film side, liquid crystal is dropped onto predetermined portions on the liquid crystal alignment film surface, then the other substrate is bonded so that the liquid crystal alignment film faces each other, the liquid crystal is spread over the entire surface of the substrate by pressing, and then the sealant is cured.

Examples of the sealant include: epoxy resin containing a curing agent and alumina balls as spacers. The liquid crystal includes nematic liquid crystal and smectic liquid crystal, and among them, nematic liquid crystal is preferable, and examples thereof include: schiff base (schiff base) liquid crystals, azoxy (azoxy) liquid crystals, biphenyl liquid crystals, phenylcyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals, diphenylcyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, cubic alkane liquid crystals, and the like. In addition, cholesteric liquid crystals, chiral agents, ferroelectric liquid crystals, and the like may be added to these liquid crystals for use.

In step 3, the following process may be performed: a liquid crystal cell containing a polymerizable monomer in a liquid crystal layer is constructed, and the constructed liquid crystal cell is irradiated with light to polymerize the polymerizable monomer, thereby imparting initial alignment to the liquid crystal. This treatment is preferably applied to a transverse electric field type such as IPS type or FFS type, and is suitable in view of obtaining a liquid crystal device having a high initial voltage holding ratio and excellent light resistance.

As the polymerizable monomer, a compound having 2 or more (meth) acryloyl groups can be preferably used from the viewpoint of high polymerizability by light. Specific examples thereof include: di (meth) acrylate having a biphenyl structure, di (meth) acrylate having a phenyl-cyclohexyl structure, di (meth) acrylate having a 2, 2-diphenylpropane structure, di (meth) acrylate having a diphenylmethane structure, di-thio (meth) acrylate having a diphenyl sulfide structure, di (meth) acrylate having a naphthalene structure, di (meth) acrylate having an anthracene structure, di (meth) acrylate having a phenanthrene structure, di (meth) acrylate having a structure that generates radicals by light irradiation, and the like. The blending ratio of the polymerizable monomer is preferably 0.1 to 1.0 mass% with respect to the total amount of the liquid crystal composition used for forming the liquid crystal layer. The polymerizable monomer may be used alone or in combination of two or more.

The light irradiation to the liquid crystal cell may be performed in a state where no voltage is applied between the pair of electrodes, in a state where a predetermined voltage (for example, 0V) for not driving the liquid crystal molecules in the liquid crystal layer is applied, or in a state where a predetermined voltage for driving the liquid crystal molecules is applied. When the liquid crystal aligning agent of the present disclosure is applied to a liquid crystal element including a transverse electric field type liquid crystal cell, the liquid crystal cell is preferably irradiated with light in a state where no voltage is applied between a pair of electrodes. As the light to be irradiated, for example, ultraviolet rays and visible rays including light having a wavelength of 150nm to 800nm, preferably ultraviolet rays including light having a wavelength of 300nm to 400nm, can be used. When the radiation used is linearly polarized light or partially polarized light, the irradiation direction of light may be performed from a vertical direction, or may be performed from an oblique direction, or may be performed by combining both. When non-polarized radiation is irradiated, the irradiation direction is set to an oblique direction.

As the light source for irradiating light, for example: low pressure mercury lamps, high pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, excimer lasers, and the like. Further, the method is as follows. The ultraviolet rays in the preferred wavelength range can be obtained by a method of using a light source in combination with, for example, a filter, a diffraction grating, or the like. As the dose of light irradiation, 1,000J/m is preferable²～200,000J/m²More preferably 1,000J/m²～100,000J/m²。

Instead of mixing the polymerizable monomer into the liquid crystal layer, the polymerizable monomer may be mixed into the liquid crystal alignment film, and the liquid crystal may be irradiated with light to impart initial alignment to the liquid crystal. In this case, in step 1, a coating film is formed on the substrate using a liquid crystal aligning agent containing a polymerizable monomer. As the polymerizable monomer contained in the liquid crystal aligning agent, a description will be given of the polymerizable monomer contained in the liquid crystal layer. The content of the polymerizable monomer is preferably 1 to 100 parts by mass, more preferably 5 to 50 parts by mass, based on 100 parts by mass of the total polymer components contained in the liquid crystal aligning agent.

Then, a polarizing plate is bonded to the outer surface of the liquid crystal cell as necessary, thereby obtaining a liquid crystal element. Examples of the polarizing plate include a polarizing plate in which a polarizing film called an "H film" in which iodine is absorbed while polyvinyl alcohol is stretched and oriented, is sandwiched between cellulose acetate protective films, and a polarizing plate including an H film itself.

The liquid crystal element of the present disclosure can be effectively applied to various applications, for example, various display devices such as a clock, a portable game machine, a word processor, a notebook Personal computer, a car navigation system, a camcorder (camcorder), a Personal Digital Assistant (PDA), a Digital camera, a mobile phone, a smart phone, various monitors, a liquid crystal television, an information display, and a light adjusting film. In addition, a liquid crystal element formed using the liquid crystal aligning agent of the present disclosure can also be applied to a retardation film.

[ examples ]

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples.

In the following examples, the weight average molecular weight Mw and the epoxy equivalent of the polymer were measured by the following methods.

[ weight-average molecular weight Mw of Polymer ]: the results of measurement by gel permeation chromatography under the following conditions using the following apparatus were obtained as a polystyrene conversion value using monodisperse polystyrene as a standard substance.

A measuring device: tosoh (Tosoh) (stock), model 8120-GPC "

Pipe column: manufactured by Tosoh corporation, "TSKgelGRCXLII"

Solvent: tetrahydrofuran (THF)

Sample concentration: 5% by weight

Sample injection amount: 100 μ L

Temperature of the pipe column: 40 deg.C

Pipe column pressure: 68kgf/cm²

[ epoxy equivalent ]: measured according to JIS C2105 "hydrochloric acid-methyl ethyl ketone method".

< Synthesis of Polymer (A) >

[ Synthesis example 1]

A solution containing a polymer (A-1) is obtained by dissolving a compound represented by the following formula (m-1) in tetrahydrofuran, and adding azobisisobutyronitrile as a polymerization initiator to conduct polymerization. The solvent in the system was subjected to solvent substitution with N-Methyl-2-pyrrolidone (NMP) with respect to the obtained polymer solution, to obtain polymer (a-1). The polymer (A-1) exhibits liquid crystallinity in a temperature range of 116 ℃ to 315 ℃.

[ solution 8]

[ Synthesis example 2]

Polymer (A-2) was obtained by the same operation as in Synthesis example 1, except that a compound represented by the following formula (m-2) was used instead of the compound represented by the formula (m-1). The polymer (A-2) exhibits liquid crystallinity in a temperature range of 108 to 313 ℃.

[ solution 9]

[ Synthesis example 3]

0.7009g (4.858mmol) of 1, 8-diaminooctane was dissolved in 22.5g of N-methyl-2-pyrrolidone (NMP), and 1.7991g (4.858mmol) of a compound represented by the following formula (m-3) was added thereto at room temperature. After stirring at 60 ℃ for 2 hours, it was cooled to room temperature to obtain a solution containing the polymer (A-3). The obtained polymer solution was poured into a sufficient excess of methanol to precipitate the reaction product. The precipitate was washed with methanol and dried at 40 ℃ for 15 hours under reduced pressure, thereby obtaining a polymer (A-3). The polymer (A-3) exhibits liquid crystallinity in a temperature range of 100 to 235 ℃.

[ solution 10]

< Synthesis of polyorganosiloxane (C) >

[ Synthesis example 4]

100.0g of 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 500g of methyl isobutyl ketone and 10.0g of triethylamine were charged into a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, and mixed at room temperature. Then, 100g of deionized water was added dropwise from the addition funnel over 30 minutes, followed by mixing under reflux and reaction at 80 ℃ for 6 hours. After the reaction was completed, the organic layer was taken out and cleaned with a 0.2 mass% ammonium nitrate aqueous solutionThe polymer (EPS-1) which is an epoxy group-containing polyorganosiloxane is obtained in the form of a viscous transparent liquid by washing until the water after washing becomes neutral and then distilling off the solvent and water under reduced pressure. Subjecting the polymer (EPS-1) to¹As a result of H-NMR analysis, a peak based on an oxirane group was obtained as a theoretical intensity in the vicinity of a chemical shift (δ) of 3.2ppm, and it was confirmed that no side reaction of an epoxy group occurred in the reaction. The polymer (EPS-1) had a weight-average molecular weight of 2,200 and an epoxy equivalent of 186 g/mol.

Then, 9.3g of the polymer (EPS-1) obtained above, 26g of methyl isobutyl ketone, 3.0g of a compound represented by the following formula (m-4), and 0.10g of the trade name "UCAT 18X" (quaternary amine salt manufactured by Santo Apro corporation) were charged into a 100mL three-necked flask, and a reaction was carried out at 80 ℃ for 12 hours with stirring. After completion of the reaction, the reaction mixture was poured into methanol to collect the formed precipitate, which was dissolved in ethyl acetate to prepare a solution, and the solution was washed with water 3 times and then the solvent was distilled off to obtain 6.3g of a polymer (C-1) which was polyorganosiloxane (C) as a white powder. The polymer (C-1) had a weight-average molecular weight Mw of 3,500.

[ solution 11]

< other ingredients >

[ Synthesis example 5]

100 parts by mole of 1,2,3, 4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 100 parts by mole of 4,4' -diaminodiphenyl ether as diamine were dissolved in NMP and reacted at 40 ℃ for 3 hours, thereby obtaining a solution containing 10 mass% of a polymer (B-1) as a polyamic acid.

[ Synthesis example 6]

100 parts by mole of 1,2,3, 4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 100 parts by mole of 4-aminophenyl-4' -aminoazobenzene as diamine were dissolved in NMP and reacted at 40 ℃ for 3 hours, thereby obtaining a solution containing 10% by mass of a polymer (B-2) as polyamic acid.

[ Synthesis example 7]

Polymer (D-1) was obtained by the same operation as in Synthesis example 1, except that octyl methacrylate was used instead of the compound represented by the formula (m-1).

[ example 1]

(1) Preparation of liquid crystal aligning agent

20 parts by mass of the polymer (A-1) obtained in Synthesis example 1 as the polymer (A), 20 parts by mass of the polymer (B-1) -containing solution obtained in Synthesis example 5 as the polymer (B) in an amount corresponding to 60 parts by mass of the polymer (B-1) and 20 parts by mass of the polymer (C-1) obtained in Synthesis example 4 as the polyorganosiloxane (C) were mixed, and N-methyl-2-pyrrolidone (NMP) and Butyl Cellosolve (Butyl Cellosolve, BC) were added thereto to prepare a mixture having a solvent composition of NMP: BC 50: 50 (mass ratio) and a solid content concentration of 4.0 mass%. The solution was filtered using a filter having a pore size of 1 μm, thereby preparing a liquid crystal aligning agent.

(2) Manufacture of liquid crystal display element

2 glass substrates with transparent electrodes comprising an ITO film were prepared, and the liquid crystal aligning agent prepared in (1) was coated on the respective transparent electrode surfaces using a spin coater. Subsequently, after pre-baking was performed on a hot plate at 80 ℃ for 1 minute, the inside of the oven was replaced with nitrogen gas, and heating was performed at 230 ℃ for 30 minutes (post-baking) to form a coating film having a thickness of 0.1 μm. Then, using an Hg-Xe lamp and a Glan-Taylor prism (Glan-Taylor prism), 500mJ/cm of polarized ultraviolet light containing 313nm bright lines was irradiated from the substrate normal direction onto the surface of each coating film²And a pair (2 pieces) of substrates having liquid crystal alignment films were produced. The irradiation dose is a value measured by using a light meter which measures with reference to the wavelength 313 nm. Then, an epoxy resin adhesive containing alumina balls having a diameter of 5.5 μm was applied to the outer edge of the surface having the liquid crystal alignment film, and the pair of substrates were stacked with the liquid crystal alignment films facing each other and pressure-bonded to each other to bond the substrates togetherThe agent hardens. Then, a nematic liquid crystal (MLC-6221, manufactured by Merck) was filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an acrylic photo-curing adhesive to manufacture a liquid crystal cell. Further, polarizing plates were bonded to both outer surfaces of the substrate of the liquid crystal cell so that the polarization directions of 2 polarizing plates were orthogonal to each other, to produce a liquid crystal display element.

(3) Evaluation of initial Voltage holding ratio

After applying a voltage of 5V at a temperature of 60 ℃ for an application time of 60 microseconds and a span of 167 milliseconds to the liquid crystal display device just after the production in the above (2), a voltage holding ratio (initial voltage holding ratio VH) after 167 milliseconds from the release of the application was measured₁). The measurement apparatus used was a product name "VHR-1" manufactured by TOYO Corporation (TOYO Corporation) of Toyang. As a result, in example 1, VH₁＝99.6％。

(4) Evaluation of light resistance

The initial voltage holding ratio VH was measured using a Weather tester (Weather Meter) using a carbon arc as a light source₁The liquid crystal display element after that was irradiated with light for 500 hours. The voltage holding ratio of the liquid crystal display device after light irradiation was measured in the same manner as in (3) above. This value is set to VH₂Introduction of VH₁Minus VH₂The decrease in the voltage holding ratio thus obtained was designated as Δ VHR, and the light resistance was evaluated by Δ VHR. As a result, in example 1, Δ VHR was 0.6%, and the light resistance was good.

(5) Evaluation of liquid Crystal alignment Properties

A liquid crystal alignment film was formed by applying and photo-aligning the liquid crystal alignment agent prepared in (1) in the same manner as in (2) on the surface of each of a pair of glass substrates provided with no electrode, and a liquid crystal cell was manufactured in the same manner as in (2) using a pair of substrates having the liquid crystal alignment film. The obtained liquid crystal cell was observed under crossed nicols (cross nicols), and as a result, uniform liquid crystal alignment without alignment failure was observed.

Further, the presence or absence of an alignment defect (abnormal region) in a change in brightness when the voltage of 5V was turned on/off (applied/released) to the liquid crystal display element obtained in (2) was visually observed, and as a result, the liquid crystal display element had no alignment defect over the entire surface, and a uniform change in the alignment of the liquid crystal due to the voltage application was observed.

Examples 2 to 8 and comparative examples 1 to 11

Liquid crystal aligning agents were prepared at the same solvent ratio and solid content concentration as in example 1, except that the kind and amount (parts by mass) of the polymer component used for the preparation of the liquid crystal aligning agent were changed as shown in table 1 below. In addition, in addition to the following table 1 changes the use of liquid crystal orientation agent, and for comparative example 3,4, 6, 9 ~ 11 in the photo-alignment treatment of exposure wavelength from 313nm to 365nm, the irradiation from 500mJ/cm²The thickness was changed to 4,000mJ/cm²Except for this point, a liquid crystal display element was manufactured in the same manner as in example 1, and the electrical characteristics, light resistance, and liquid crystal alignment properties were evaluated in the same manner as in example 1. The results are shown in table 1 below. Furthermore, at 500mJ/cm²When the polymer (B-1) was irradiated with polarized ultraviolet light containing a bright line of 313nm, no photocleavage reaction occurred in the polymer (B-1). Therefore, the polymer (B-1) corresponds to a non-photosensitive polymer with respect to the polyorganosiloxane (C).

[ example 9]

(1) Preparation of liquid Crystal composition

In a nematic liquid crystal (MLC-6221, manufactured by merck corporation), 0.5 mass% of a mixture of a compound represented by the following formula (L-1) and a compound represented by the following formula (L-2) as polymerizable monomers was added to the total amount of the nematic liquid crystal (mass mixing ratio (L-1): 50) and mixed, thereby obtaining a liquid crystal composition LC 1.

[ solution 12]

(2) Manufacture of transverse electric field type liquid crystal display element

A glass substrate having a metal electrode containing chromium patterned in a comb-tooth shape on one surface and an opposing glass substrate having no electrode were paired, a liquid crystal aligning agent E (liquid crystal aligning agent used in example 4) was applied to the surface of the glass substrate having the electrode and the one surface of the opposing glass substrate using a spinner, prebaked on a hot plate at 80 ℃ for 1 minute, and then heated at 200 ℃ for 1 hour in an oven with nitrogen substitution in the chamber (post-baking), thereby forming a coating film having a thickness of 0.1 μm.

Then, using an Hg-Xe lamp and a Glan-Taylor prism, the surface of each coating film was irradiated with 300mJ/cm of polarized ultraviolet light containing 313nm bright line from the substrate normal direction²(photo-alignment treatment) to obtain a pair of substrates having liquid crystal alignment films. An epoxy adhesive containing alumina balls having a diameter of 5.5 μm was applied to the outer periphery of the surface having the liquid crystal alignment film of one of the substrates by screen printing, and then the liquid crystal alignment films of the pair of substrates were opposed to each other, and the substrates were stacked and pressure-bonded so that the orientations of the substrates were opposite to each other when irradiated with polarized ultraviolet rays, and the adhesive was heat-cured at 150 ℃ for 1 hour.

Subsequently, the gap between the substrates was filled with the liquid crystal composition LC1 prepared in (1), and the liquid crystal injection port was sealed with an epoxy adhesive. Thereafter, in order to remove the flow alignment at the time of liquid crystal injection, the liquid crystal cell was heated at 150 ℃ and then slowly cooled to room temperature, and further, Ultraviolet (UV) light irradiation (irradiation amount: 2,000 mJ/cm) was performed from the outside of the liquid crystal cell in a state where no voltage was applied between the pair of electrodes²(λ 365 nm)). Then, polarizing plates were bonded to both outer surfaces of the substrate so that the polarization directions thereof were orthogonal to each other and to the projection direction of the optical axis of the polarized ultraviolet ray of the liquid crystal alignment film with respect to the substrate surface, thereby producing a liquid crystal display element.

(2) Evaluation of

The liquid crystal display element manufactured in (1) above was subjected to the electrical characteristics, light resistance and liquid crystal alignment in the same manner as in example 1And (4) evaluating the performance. As a result, in this example, VH₁99.2%, Δ VHR 0.3%. The liquid crystal alignment properties were also good as in example 1.

Example 10, comparative example 12 and comparative example 13

In addition to the change of the liquid crystal aligning agent used as shown in the following Table 1, the exposure wavelength in the photo-alignment treatment was changed from 313nm to 365nm and the irradiation dose was changed from 500mJ/cm for comparative example 13²The thickness was changed to 4,000mJ/cm²Except for this point, a liquid crystal display element was produced in the same manner as in example 9, and the electrical characteristics, light resistance and liquid crystal alignment properties were evaluated in the same manner as in example 1. The results are shown in table 1 below.

[ example 11]

(1) Preparation of liquid crystal aligning agent

20 parts by mass of the polymer (A-2) obtained in Synthesis example 2 as the polymer (A), 60 parts by mass of the polymer (B-1) -containing solution obtained in Synthesis example 5 as the polymer (B) in terms of polymer (B-1), and 20 parts by mass of the polymer (C-1) obtained in Synthesis example 4 as the polyorganosiloxane (C) were mixed, and N-methyl-2-pyrrolidone (NMP) and Butyl Cellosolve (BC) were added thereto, and further 20 parts by mass of a compound represented by the following formula (E-1) as a polymerizable monomer was added to prepare a solvent composition of NMP: BC 50: 50 (mass ratio) and a solid content concentration of 4.0 mass%. The solution was filtered using a filter having a pore size of 1 μm, thereby preparing a liquid crystal aligning agent T.

[ solution 13]

(2) Production and evaluation of liquid Crystal display element

A liquid crystal display element was produced in the same manner as in example 9 except that the liquid crystal aligning agent used was the liquid crystal aligning agent T prepared in (1) and MLC-6221 (manufactured by merck) was filled in the gap between the substrates instead of liquid crystal composition LC1, and the electrical characteristics, the light resistance, and the liquid crystal alignment property were evaluated in the same manner as in example 1. The results are shown in table 1 below.

[ Table 1]

As is clear from table 1, the initial voltage holding ratios of the liquid crystal display devices of examples 1 to 11 were as high as 98.0% or more. In addition, Δ VHR was 0.9% or less, and light resistance was also good. In examples 1 to 11, the liquid crystal alignment properties were also good. On the other hand, the liquid crystal aligning agents of comparative examples 1 to 13 are inferior to the liquid crystal aligning agents of examples 1 to 11 in at least one of the initial voltage holding ratio and the light resistance. With respect to the liquid crystal alignment properties, no liquid crystal alignment was observed in comparative example 2, and many alignment defects were observed when a voltage was applied and released in examples (comparative examples 5 to 9) in which a (meth) acrylic polymer exhibiting no liquid crystal properties was used instead of the polymer (a). In comparative example 10 in which the photosensitive polyamic acid polymer (B-2) was used in place of the photosensitive polyorganosiloxane (C)), many alignment defects were observed.

Claims

1. A liquid crystal aligning agent characterized in that: comprises that

A polyorganosiloxane (C) having a group containing a cinnamic acid structure; and

a polymer (A) having a partial structure exhibiting liquid crystallinity and exhibiting liquid crystallinity,

wherein the polymer (A) is a polymer of a monomer having a polymerizable unsaturated bond, the monomer having a polymerizable unsaturated bond including at least one compound represented by any one of the following formulae (2-1) to (2-5),

1 to 80 parts by mass of a polymer (A) per 100 parts by mass of the total polymer components contained in the liquid crystal aligning agent,

1 to 99 parts by mass of a polyorganosiloxane (C) per 100 parts by mass of the total polymer components contained in the liquid crystal aligning agent,

in the formulae (2-1) to (2-5), R²Is a hydrogen atom or a methyl group, R³Is C1-12 alkanediyl or divalent group obtained by substituting at least 1 methylene group of the alkanediyl with-O-, R⁴Is an alkyl group, alkoxy group or fluoroalkyl group having 1 to 20 carbon atoms, or a fluorine atom.

2. The liquid crystal aligning agent according to claim 1, wherein: including at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

3. A liquid crystal alignment film characterized in that: formed using the liquid crystal aligning agent according to claim 1 or 2.

4. A liquid crystal cell, characterized by: comprising the liquid crystal alignment film according to claim 3.

5. A method for manufacturing a liquid crystal alignment film, comprising: comprising the steps of applying the liquid crystal aligning agent according to claim 1 or 2 to a substrate to form a coating film, and irradiating the substrate surface on which the liquid crystal aligning agent is applied with light to impart liquid crystal aligning ability to the coating film.

6. A method of manufacturing a liquid crystal element, characterized by: comprises that

A step of forming a liquid crystal alignment film on each surface of the pair of substrates by the method for manufacturing a liquid crystal alignment film according to claim 5;

a step of configuring a liquid crystal cell by disposing the pair of substrates with a liquid crystal layer containing a polymerizable monomer interposed therebetween such that the respective liquid crystal alignment films face each other; and

and irradiating the liquid crystal cell with light.

7. A method of manufacturing a liquid crystal element, characterized by: comprises that

A step of forming a liquid crystal alignment film on the surface of each of the pair of substrates by the method for producing a liquid crystal alignment film according to claim 5 using a liquid crystal aligning agent containing a polymerizable monomer;

a step of configuring a liquid crystal cell by disposing the pair of substrates with a liquid crystal layer interposed therebetween such that the respective liquid crystal alignment films face each other; and

and irradiating the liquid crystal cell with light.