TWI791838B - Liquid crystal alignment agent, liquid crystal alignment film, liquid crystal element, and method for manufacturing liquid crystal element - Google Patents

Abstract

（式（1）中，R¹ ～R⁶ 分別獨立地為氫原子或碳數1～20的一價有機基。其中，R¹ ～R⁶ 中的至少一個為具有交聯性基的一價有機基。n為1～18的整數。於n為2以上的情況下，多個R¹ 彼此可相同亦可不同，多個R² 彼此可相同亦可不同）The present invention provides a liquid crystal alignment agent capable of obtaining a liquid crystal element having excellent light resistance and heat resistance. The liquid crystal alignment agent contains: a polymer component; and a cyclic siloxane compound [A] having a crosslinkable group. An example of the cyclic siloxane compound [A] is a compound represented by formula (1).

(In formula (1), R ¹ to R ⁶ are each independently a hydrogen atom or a monovalent organic group with 1 to 20 carbon atoms. Among them, at least one of R ¹ to R ⁶ is a monovalent organic group having a crosslinkable group Organic group. n is an integer of 1 to 18. When n is 2 or more, multiple R ¹ may be the same or different from each other, and multiple R ² may be the same or different from each other)

Description

Liquid crystal alignment agent, liquid crystal alignment film, liquid crystal element, and method for manufacturing liquid crystal element

The invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal element and a method for manufacturing the 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. Usually, the liquid crystal alignment film is formed on the substrate by applying a liquid crystal alignment agent prepared by dissolving polymer components in an organic solvent on the surface of the substrate, and preferably heating.

In recent years, large-screen and high-definition LCD TVs have become the mainstay, and small display terminals such as smart phones and tablet personal computers (tablet PCs) are becoming popular, and the demand for high-quality liquid crystal elements is higher than before. And improve. Therefore, in order to improve the performance of the liquid crystal alignment film and make various characteristics of the liquid crystal cell excellent, various liquid crystal alignment agents have been proposed (for example, refer to Patent Document 1 to Patent Document 3).

Patent Document 1 discloses that a liquid crystal alignment agent contains polyimide and an epoxy compound having a nitrogen atom (for example, N,N,N',N'-tetraglycidyl-4,4'-diamine diphenylmethane, 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane, etc.). In addition, Patent Document 2 discloses that the liquid crystal alignment agent contains polyamic acid or Polyimide, and a compound containing an imide bond and two or more epoxy groups (for example, monoallyl diglycidyl isocyanuric acid, triglycidyl isocyanuric acid, etc.). Patent Document 3 discloses that polyamic acid or polyimide and a polyfunctional epoxy compound having two or more 3,4-epoxycyclohexane rings are contained in a liquid crystal alignment agent.

[Prior art literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 10-333153

[Patent Document 2] Japanese Patent Laid-Open No. 2007-139949

[Patent Document 3] Japanese Patent Laid-Open No. 2016-170409

Liquid crystal elements are not only used in display terminals such as personal computers as before, but are also used in LCD TVs, car navigation systems, mobile phones, smart phones, information displays, etc., regardless of indoors and outdoors. ), phase difference film, dimming film and many other uses. In addition, with the expansion of applications, it is assumed that the liquid crystal element is used in a harsher environment than before. Specifically, a liquid crystal element may be continuously driven for a long time to irradiate a backlight for a long time, or be 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 element performance is required to be maintained even under severe environmental conditions.

This invention is made in view of the said situation, and the main object is to provide the liquid crystal aligning agent which can obtain the liquid crystal element excellent in light resistance and heat resistance.

According to the present invention, the following means are provided.

[1] A liquid crystal alignment agent comprising: a polymer component; and a cyclic siloxane compound [A] having a crosslinkable group.

[2] A liquid crystal alignment film formed using the liquid crystal alignment agent of [1].

[3] A liquid crystal element including the liquid crystal alignment film of the above [2].

[4] A method of manufacturing a liquid crystal element, comprising: applying the liquid crystal alignment agent of [1] to each of a pair of substrates and irradiating light to form a liquid crystal alignment film; The step of constructing a liquid crystal cell by arranging the pair of substrates of the liquid crystal alignment film so that the liquid crystal alignment films face each other with a liquid crystal layer interposed therebetween.

[5] A method for manufacturing a liquid crystal element, comprising: applying the liquid crystal alignment agent of [1] on the respective conductive films of a pair of substrates having a conductive film to form a coating film; The step of constructing a liquid crystal cell by arranging the pair of substrates covered with the liquid crystal alignment agent so that the coating films face each other across the liquid crystal layer; and applying a voltage to the conductive film Step of light irradiation of liquid crystal cell.

According to the liquid crystal alignment agent of this invention, the liquid crystal element excellent in light resistance and heat resistance can be obtained by containing a cyclic siloxane compound [A].

<<Liquid crystal alignment agent>>

The liquid crystal alignment agent disclosed herein contains polymer components and additive components. In addition, as an additive component, a cyclic siloxane compound [A] having a crosslinkable group is contained. Hereinafter, each component contained in a liquid crystal alignment agent, and other components arbitrarily blended as needed are demonstrated.

In addition, in this specification, a "hydrocarbon group" is meant to include a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The term "chain hydrocarbon group" refers to a straight chain hydrocarbon group and a branched hydrocarbon group that does not contain a cyclic structure in the main chain but only consists of a chain structure. Among them, it may be saturated or unsaturated. The "alicyclic hydrocarbon group" refers to a hydrocarbon group including only an alicyclic hydrocarbon structure as a ring structure and not including an aromatic ring structure. Among these, it is not necessary to consist only of the structure of an alicyclic hydrocarbon, but what has a chain structure in a part is also included. The "aromatic hydrocarbon group" refers to a hydrocarbon group including an aromatic ring structure as a ring structure. However, it is not necessary to consist only of an aromatic ring structure, and may include a chain structure or an alicyclic hydrocarbon structure in a part thereof.

<polymer composition>

The polymer component contained in a liquid crystal alignment agent should just be crosslinked by the cyclic siloxane compound [A], and the kind of the main skeleton is not specifically limited. Specific examples of polymer components include polyamic acid, polyamide ester, polyimide, polyorganosiloxane, polyester, polyamide, polyamideimide, polyphenylene Ethylene, polybenzoxazole precursor, polybenzoxazole, cellulose derivatives, polyacetal, polymaleimide, styrene-maleimide copolymer, or poly(methyl) Acrylate-based polymers. In addition, (meth)acrylate refers to acrylate and methacrylic esters.

As a polymer component, among these, it is easy to promote the crosslinking reaction with the cyclic siloxane compound [A], the compatibility with the cyclic siloxane compound [A] is better, and Cyclic siloxane compounds [A] are preferably selected from polyamic acid, polyamic acid ester, At least one selected from the group consisting of polyimide and a polymer having a structural unit derived from a monomer having a polymerizable unsaturated bond. The polymer component has a functional group (hereinafter also referred to as "reactive functional group") capable of reacting with the crosslinkable group of the cyclic siloxane compound [A]. This reactive functional group can be suitably designed according to the crosslinkable group which cyclic siloxane compound [A] has. Hereinafter, preferable examples of the polymer component will be described respectively.

(polyamide)

Polyamic acid can be obtained by making tetracarboxylic dianhydride and a diamine compound react.

． Tetracarboxylic dianhydride

As a tetracarboxylic dianhydride used for synthesis|combination of polyamic acid, aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride etc. are mentioned, for example. As specific examples of these, aliphatic tetracarboxylic dianhydrides include, for example: 1,2,3,4-butane tetracarboxylic dianhydride, etc.; alicyclic tetracarboxylic dianhydrides include, for example: 1,2 ,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl Acetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5 -(2,5-Dioxytetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphthalene And[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2,4,6,8-dianhydride, cyclopentane Tetracarboxylic dianhydride, cyclohexane tetracarboxylic dianhydride, etc.; examples of aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene) diphthalic acid In addition to formic anhydride, ethylene glycol bis-trimellitic anhydride, 4,4'-carbonyl diphthalic anhydride, etc., tetracarboxylic dianhydrides described in JP-A-2010-97188 can also be used. . In addition, tetracarboxylic dianhydride can be used individually by 1 type or in combination of 2 or more types.

． Diamine compound

Examples of the diamine compound used in the synthesis of polyamic acid include aliphatic diamine, alicyclic diamine, aromatic diamine, and diaminoorganosiloxane. As specific examples of these diamines, aliphatic diamines include: m-xylylenediamine, 1,3-propylenediamine, hexamethylenediamine, etc.; alicyclic diamines include: 1,4- Diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), etc.; examples of aromatic diamines include hexadecyloxy-2,4-diaminobenzene, octadecyloxy -2,4-Diaminobenzene, Octadecyloxy-2,5-Diaminobenzene, Cholesteryloxy-3,5-Diaminobenzene, Cholesteryloxy-3,5- Diaminobenzene, Cholesteryloxy-2,4-diaminobenzene, Cholesteryloxy-2,4-diaminobenzene, Cholesteryl 3,5-diaminobenzoate, 3,5-Diaminobenzoic acid cholestenyl ester, 3,5-diaminobenzoic acid lanostyl ester, 3,6-bis(4-aminobenzoyloxy)cholestane , 3,6-bis(4-aminophenoxy)cholestane, 2,4-diamino-N,N-diallylaniline, 4-(4'-trifluoromethoxybenzyl Acyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 3 ,5-diaminobenzoic acid=5ξ-cholestan-3-yl, the following formula (E-1)

[chemical 1]

(In formula (E-1), X ^I and X ^II are each independently a single bond, -O-, *-COO- or *-OCO- (wherein, "*" represents a bond with X ^I ), R ^I is an alkanediyl group with 1 to 3 carbons, R ^II is a single bond or an alkanediyl group with 1 to 3 carbons, a is 0 or 1, b is an integer of 0 to 2, and c is an integer of 1 to 20, d is 0 or 1. Among them, a and b will not be 0 at the same time)

Side-chain diamines such as the compounds represented: p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4-aminophenyl-4-aminobenzoate, 4,4'- Diaminoazobenzene, 3,5-diaminobenzoic acid, 1,5-bis(4-aminophenoxy)pentane, 1,2-bis(4-aminophenoxy)ethane , bis[2-(4-aminophenyl)ethyl]adipic acid, N,N-bis(4-aminophenyl)methylamine, 1,4-bis-(4-aminophenyl )-piperazine, N,N'-bis(4-aminophenyl)-benzidine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis( Trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl] Propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(phenylenediisopropylidene)bisaniline, 1,4-bis(4-aminophenoxy ) benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-di base)] diphenylamine, 4,4'-diaminobenzylaniline, 4,4'-diaminostilbene, 4,4'-diaminodiphenylamine, 1,3-bis( 4-aminophenethyl)urea, 1,3-bis(4-aminobenzyl)urea, 1,4-bis(4-aminophenyl)-piperazine, N-(4-aminobenzene Ethyl)-N-methylamine, N,N'-bis(4-aminophenyl)-N,N'- Main-chain diamines such as dimethylbenzidine; diaminoorganosiloxanes include, for example, 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, etc. In addition, The diamine described in Unexamined-Japanese-Patent No. 2010-97188 can also be used.

． Synthesis of polyamic acid

Polyamic acid can be obtained by making a tetracarboxylic dianhydride and a diamine compound react together with a molecular weight modifier (for example, an acid monoanhydride, a monoamine, etc.) as needed. The use ratio of the tetracarboxylic dianhydride and the diamine compound used in the synthesis reaction of polyamic acid is preferably 0.2 to 2 equivalents of the anhydride group of the tetracarboxylic dianhydride relative to 1 equivalent of the amine group of the diamine compound. Equivalent ratio.

The synthesis reaction of polyamic acid is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20° C. to 150° C., and the reaction time is preferably 0.1 hour to 24 hours. Examples of the organic solvent used in the reaction include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. A particularly good organic solvent is preferably selected from N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, One or more of the group consisting of γ-butyrolactone, tetramethylurea, hexamethylphosphoryltriamine, m-cresol, xylenol, and halogenated phenol is used as a solvent, or one or more of these are used together with Mixtures with other organic solvents (eg, butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount (a) of the organic solvent used is preferably such that the total amount (b) of tetracarboxylic dianhydride and diamine becomes 0.1% by mass to 50% by mass with respect to the total amount of the reaction solution (a+b). quantity.

(Polyuric acid ester)

Polyamic acid ester, for example, can be obtained by the following method, etc.: [I] make by the synthesis A method of reacting polyamic acid obtained by the reaction with an esterifying agent; [II] a method of reacting a tetracarboxylic acid diester with a diamine compound; [III] making a tetracarboxylic acid diester dihalide and a diamine compound A method for reacting amine compounds. The polyamic acid ester contained in the liquid crystal alignment agent may only have the uric acid ester structure, and may also be a partial esterification product in which the uric acid structure and the uric acid ester structure coexist.

(polyimide)

Polyimide can be obtained, for example, by dehydrating and ring-closing polyamic acid synthesized as described above, and imidizing it. The imidization rate of polyimide is preferably 20%-99%, more preferably 30%-90%. The imidization ratio represents the ratio of the number of imide ring structures to the sum of the number of amide acid structures and the number of imide ring structures in polyimide, as a percentage. Furthermore, a part of the imide ring may be an isoimide ring.

The dehydration and ring closure of polyamic acid is preferably carried out 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 heating if necessary. In this method, examples of 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 mol to 20 mol with respect to 1 mol of the amide acid structure of the polyamic acid. As 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 mol to 10 mol with respect to 1 mol of the dehydrating agent used. Examples of the organic solvent used in the dehydration ring-closure reaction include the organic solvents exemplified as used in the synthesis of polyamic acid. The reaction temperature of the dehydration ring-closing reaction is preferably 0°C to 180°C. The reaction time is preferably from 1.0 hour to 120 hours.

(a polymer having a structural unit derived from a monomer having a polymerizable unsaturated bond)

As a polymer having a structural unit derived from a monomer having a polymerizable unsaturated bond (hereinafter also referred to as "polymer [Pm]"), for example, poly(meth)acrylate, styrene-mass Polyimide-based copolymers, polystyrene, polymaleimide, etc. In terms of the ease of introduction of alignment groups and the better reliability of the obtained liquid crystal element, it is preferably selected from poly(meth)acrylates and styrene-maleimide copolymers. At least one of the group consisting of.

In addition, in this specification, an "orientation group" is a group which can provide a pretilt angle to the liquid crystal molecule in a liquid crystal layer when a liquid crystal alignment film is arrange|positioned adjacent to a liquid crystal layer. Specifically, a group capable of imparting a pretilt angle to liquid crystal molecules without being irradiated with light (hereinafter, also referred to as a "vertical alignment group") and a photoalignment group are exemplified. Specific examples of the vertical alignment group include, for example, an alkyl group having 4 to 20 carbons, an alkoxy group having 4 to 20 carbons, a fluoroalkyl group having 4 to 20 carbons, and a fluorine group having 4 to 20 carbons. Substituted alkoxy group, two or more rings (preferably at least one ring selected from the group consisting of cyclohexane ring, benzene ring and naphthalene ring) directly or through a divalent linking group (such as oxygen atom, - A group having a mesogen structure formed by CO- or -COO-), a group having a steroid skeleton, and the like.

The monomer used in the synthesis of the polymer [Pm] is not particularly limited as long as it has a polymerizable unsaturated bond, and examples include: Compounds with polymerizable unsaturated bonds such as amine groups. Specific examples of these compounds include: (meth)acrylic acid, α-ethacrylic acid, methacrylic acid, Unsaturated carboxylic acids such as toric acid, fumaric acid, and vinyl benzoic acid; alkyl (meth)acrylates (such as methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.), Cycloalkyl (meth)acrylate, Benzyl (meth)acrylate, Trimethoxysilylpropyl (meth)acrylate, 2-Hydroxyethyl (meth)acrylate, Glycidyl (meth)acrylate Ester, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 4-hydroxybutyl glycidyl acrylate and other unsaturated carboxylic acid esters ; Maleic anhydride and other unsaturated polycarboxylic acid anhydrides: (meth) acrylic compounds such as; styrene, methylstyrene, divinylbenzene, 4-(glycidyloxymethyl) styrene and other aromatic vinyl Compounds; 1,3-butadiene, 2-methyl-1,3-butadiene and other conjugated diene compounds; N-methylmaleimide, N-cyclohexylmaleimide, N -Phenylmaleimide, 4-(2,5-dioxo-3-pyrrolin-1-yl)benzoic acid, N-(4-glycidyloxyphenyl)maleimide, N-glycidylmaleimide, 3-maleimide benzoic acid, 3-maleimide propionate, 3-(2,5-dioxo-3-pyrroline-1-yl ) benzoic acid, maleimide compounds such as methyl 4-(2,5-dioxo-3-pyrrolin-1-yl)benzoate, etc. In addition, when the polymer [Pm] is a polymer having a photoalignment group, a compound having a photoalignment group can also be used as a monomer having a polymerizable unsaturated bond. The monomer having a polymerizable unsaturated bond can be used alone or in combination of two or more. In addition, in this specification, "(meth)acryl" means "acryl" and "methacryl". In addition, "(meth)acryl" means "acryl" and "methacryl".

The polymer [Pm] can be obtained by, for example, having Obtained by polymerizing monomers with polymerizable unsaturated bonds. As the polymerization initiator used, for example, 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2 Azo compounds such as '-azobis(4-methoxy-2,4-dimethylvaleronitrile). It is preferable that the usage ratio of a polymerization initiator shall be 0.01 mass part - 30 mass parts with respect to 100 mass parts of all monomers used for reaction. The polymerization reaction is preferably carried out in an organic solvent. Examples of the organic solvent used in the reaction include alcohols, ethers, ketones, amides, esters, hydrocarbon compounds, and the like, preferably diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether acetate, and the like. The reaction temperature is preferably set at 30° C. to 120° C., and the reaction time is preferably set at 1 hour to 36 hours. The usage-amount (a) of the organic solvent is preferably such that the total amount (b) of the monomers used in the reaction becomes 0.1% by mass to 60% by mass with respect to the total amount (a+b) of the reaction solution.

The polymer component preferably has a polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (Gel Permeation Chromatography, GPC) of 1,500 to 500,000, more preferably 2,500 to 100,000.

Furthermore, in the polymerization reaction for obtaining each polymer, when the reaction solution containing the polymer is obtained, the reaction solution can be directly used for the preparation of the liquid crystal alignment agent, or the polymer can be separated and then used in Preparation of liquid crystal alignment agent. The method for isolating the polymer is not particularly limited, and it can be carried out according to a known method.

When imparting liquid crystal alignment capability to an organic film formed using a liquid crystal alignment agent using a photoalignment method, it is preferable to make at least a part of the polymer component a polymer having a photoalignment group. Photoalignment group refers to the photoisomerization reaction, photodimerization reaction, photo Fries rearrangement (photo Fries A functional group that imparts anisotropy to the film by a photoreaction such as a rearrangement reaction or a photodecomposition reaction.

Specific examples of the photoalignment group include, for example, an azobenzene-containing group containing azobenzene or its derivatives as a basic skeleton, a group containing cinnamic acid or a derivative thereof (cinnamic acid structure) as a basic skeleton, A group of cinnamic acid structure, a chalcone-containing group containing chalcone or a derivative thereof as a basic skeleton, a benzophenone-containing group containing a benzophenone or a derivative thereof as a basic skeleton, a group containing Coumarin-containing groups containing coumarin or its derivatives as the basic skeleton, cyclobutane-containing structures containing cyclobutane or its derivatives as the basic skeleton, stilbene or its derivatives as the basic skeleton A stilbene-containing group, a phenylbenzoate-containing group containing phenylbenzoate or a derivative thereof as a basic skeleton, and the like. Among these, the photoalignment group is preferably selected from groups containing azobenzene, groups containing cinnamic acid structures, groups containing chalcone, groups containing stilbene, and groups containing cyclobutane. structure, and at least one of the group consisting of a phenylbenzoate-containing group is preferably a cinnamic acid-containing structure in terms of high sensitivity to light and ease of introduction into polymers. groups or structures containing cyclobutane.

A polymer having a photoalignment group can be obtained, for example, by the following methods: (1) a method obtained by polymerizing a monomer having a photoalignment group; (2) synthesizing a polymer having an epoxy group in a side chain A polymer, and a method of reacting the epoxy-containing polymer with a carboxylic acid having a photoalignment group. The content ratio of the photoalignment group in a polymer is suitably set according to the kind of photoalignment group so that desired liquid crystal alignment ability may be provided to a coating film. For example, in the case of a group containing a cinnamic acid structure, relative to In all the constituent units of the polymer having a photoalignment group, the content ratio of the photoalignment group is preferably 5 mol % or more, more preferably 10 mol % to 60 mol %. In the case where the photoalignment group has a cyclobutane-containing structure, it is preferable to set the content ratio of the photoalignment group to 50 mol % or more with respect to all the constituent units of the polymer having the photoalignment group, More preferably, it is 80 mol% or more. In addition, the polymer which has a photoalignment group may be used individually by 1 type, and may use it in combination of 2 or more types.

The polymer component contained in the liquid crystal alignment agent may be one kind alone, but it is preferably set as a polymer blend (polymer blend) containing two or more kinds of polymers. In the case of preparing a crosslinking agent in a 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 cannot be efficiently carried out when the film is formed, and there is a concern that it will not be possible Fully obtain the effect brought by the formulation of the crosslinking agent. On the other hand, according to the cyclic siloxane compound [A], it is thought that the compatibility with a polymer and the solubility with respect to a solvent are high, and it can be easily dispersed in the crosslinking point of a polymer. As a result, it is presumed that the reaction efficiency of the crosslinking reaction can be improved even when it is a polymer blend, and a liquid crystal element excellent in light resistance and heat resistance can be obtained.

As a preferable example of a liquid crystal aligning agent, the liquid crystal aligning agent contains a 1st polymer and a 2nd polymer whose polarity is higher than a 1st polymer. In this case, it is preferable that the second polymer with high polarity tends to exist in the lower layer, and the first polymer tends to exist in the upper layer, so that phase separation can occur. The following (I)-(III) can be mentioned as a preferable aspect of the polymer component of a liquid crystal alignment agent.

(1) The aspect in which the first polymer and the second polymer are polymers selected from the group consisting of polyamide acid, polyamide ester, and polyimide.

(II) One of the first polymer and the second polymer is a polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and the other is a polymer The form of the body [Pm].

(III) An aspect in which the first polymer and the second polymer are polymer [Pm].

In the aspect of (II) above, polyamic acid, polyamic acid ester, and polyimidic The total content ratio of the amines is preferably at least 20% by mass, more preferably at least 30% by mass, and still more preferably at least 50% by mass, based on the total amount of the polymer components contained in the liquid crystal alignment agent. ~90% by mass. In the case of imparting liquid crystal alignment ability to an organic film formed using a liquid crystal alignment agent by a photoalignment method, a polymer with high liquid crystal alignment can be obtained by making the polymer [Pm] a polymer having a photoalignment group. An alignment film is preferable in this respect.

From the viewpoint of sufficiently improving the film strength, the content ratio of the polymer component in the liquid crystal alignment agent is relatively high relative to the total mass of the solid content contained in the liquid crystal alignment agent (the total mass of the components of the liquid crystal alignment agent except the solvent). Preferably, it is 50 mass % or more, More preferably, it is 60 mass % or more, More preferably, it is 70 mass % or more.

<Cyclic Siloxane Compound [A]>

The cyclic siloxane compound [A] is a cyclic compound having one cyclic skeleton formed of a siloxane bond (Si—O bond) in the molecule, and has a crosslinkable group. The crosslinkable group is not particularly limited as long as it is a group capable of covalently bonding with other groups to form a crosslinked structure, for example, an oxiranyl group, an oxycyclobutyl group, a (methyl ) Acryl, allyl, vinylphenyl, cyclic carbonate, hydroxymethyl, amine, etc. As the cross-linking group, in terms of improving the storage stability of the liquid crystal alignment agent, it is preferably selected from the group consisting of oxirane group, oxetanyl group and (meth)acryl group. At least one, particularly preferably oxirane group. In addition, in this specification, "(meth)acryl" is the meaning which includes "acryl" and "methacryl".

The number of crosslinkable groups contained in the cyclic siloxane compound [A] is preferably 2 or more, more preferably 3 or more, and more preferably 4 or more. In addition, from the viewpoint of better compatibility with polymer components, easier dispersion, and suppression of performance degradation caused by film shrinkage of the formed liquid crystal alignment film, the number of crosslinkable groups The upper limit is preferably 10 or less, more preferably 8 or less.

Furthermore, in the case of using a liquid crystal alignment agent to form a liquid crystal alignment film, the reactivity of the crosslinkable group of the cyclic siloxane compound [A] and the polymer component is reversed by heating at the time of film formation. The functional groups react to form a cross-linked structure. The combination of the crosslinkable group and the reactive functional group can be appropriately selected according to storage stability, ease of introduction into a polymer, reactivity to heat or light, and the like. Specifically, when the crosslinkable group is an epoxy group, the reactive functional group includes a carboxyl group, a hydroxyl group, an amino group, etc., and is preferably a carboxyl group in terms of good storage stability. Moreover, when a crosslinkable group is a (meth)acryloyl group, a thiol group, a (meth)acryloyl group, etc. are mentioned as a reactive functional group. When the crosslinkable group is a vinyl group, the reactive functional group includes a thiol group, a vinyl group, etc., and when the crosslinkable group is an amine group, the reactive functional group includes a carboxyl group, a hydroxyl group, a ring, etc. Oxygen, halogen atoms, etc. in cross-linking When the reactive group is a cyclic carbonate group, the reactive functional group can be amine group, hydroxyl group, carboxyl group, epoxy group, acid anhydride group, and when the crosslinkable group is a methylol group, the reactive functional group can be Examples include: epoxy group, amino group, hydroxyl group, 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).

(In formula (1), R ¹ ~ R ⁶ are each independently a hydrogen atom or a monovalent organic group with 1 to 20 carbons. Wherein, at least one of R ¹ ~ R ⁶ is a monovalent organic group with a crosslinkable group Organic group. n is an integer of 1 to 18. When n is 2 or more, multiple R ¹ may be the same or different from each other, and multiple R ² may be the same or different from each other)

In the formula (1), when R ¹ to R ⁶ are monovalent organic groups, specific examples thereof include: a monovalent hydrocarbon group with 1 to 20 carbon atoms, at least one hydrogen atom of the monovalent hydrocarbon group A monovalent group substituted with a crosslinkable group having -O-, -COO-, -S-, -NR ¹⁰ - or -CONR ¹⁰ - (R ¹⁰ is hydrogen) between the carbon-carbon bonds of the hydrocarbon group atom or a monovalent hydrocarbon group with 1 to 10 carbons), a monovalent group with 2 to 20 carbons, at least one hydrogen atom of the monovalent group with 2 to 20 carbons is substituted with a crosslinkable group Monovalent groups, etc., these groups may have substituents. As a substituent, a hydroxyl group, a halogen atom, etc. are mentioned, for example.

In terms of easy dispersion in the liquid crystal alignment agent, and better compatibility with polymer components and better solubility in solvents, R ¹ to R ⁶ are preferably those with 1 to 20 carbon atoms. Monovalent organic group. The carbon numbers of R ¹ -R ⁶ are preferably 1-15, more preferably 1-10.

Among R ¹ to R ⁶ , 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 formula (2), R ⁷ is a divalent group having a chain structure, and X ¹ is a monovalent group having a crosslinkable group. "* ¹ " indicates a bond with a silicon atom)

In the formula (2), the chain structure of ^R7 is preferably an alkanediyl group with 1 to 10 carbons, or a group with -O- or -S- between the carbon-carbon bonds of the alkanediyl group , may also have a substituent. The carbon number of R ⁷ is preferably 1-7, more preferably 2-5.

From the viewpoint of the storage stability of the liquid crystal alignment agent, ^X1 is preferably a monovalent group having an epoxy group (oxirane group or oxetane group), for example, glycidyloxy group, ring Oxycyclohexyl, etc.

Preferably, at least one of the two monovalent groups bonded to the silicon atom in the formula (1) (R ¹ , R ³ and R ⁵ ) is a group represented by the formula (2), and One (R ² , R ⁴ and R ⁶ ) is a monovalent hydrocarbon group with 1-10 carbons. 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.

From the viewpoint of the dispersibility in the liquid crystal alignment agent, the compatibility with the polymer component, and the ease of acquisition of the material, n is preferably 1-10, more preferably 1-6, particularly preferably 1-4 .

The cyclic siloxane compound [A] may further have a photoreactive group. Since the cyclic siloxane compound [A] has a photoreactive group, it can cause self-crosslinking due to thermal reaction of the photoreactive group, and stabilize alignment by polymer (Polymer Sustained Alignment, PSA) When processing and obtaining a liquid crystal element, it is preferable at the point that the light resistance and heat resistance equivalent to a crosslinkable group can be acquired. The photoreactive group is preferably a group having a carbon-carbon unsaturated bond, for example, a (meth)acryl group, a vinylphenyl group, a vinyl group, and the like. Among these, a (meth)acryloyl group is particularly preferable at the point that photoreactivity is high and self-crosslinking by thermal reaction of the photoreactive group easily occurs. When the cyclic siloxane compound [A] has a photoreactive group, the number of the photoreactive group is preferably 1 to 4, more preferably 1 in order to sufficiently ensure the number of crosslinkable groups introduced. or 2.

It is easy to disperse in the liquid crystal alignment agent, it can make the compatibility with the polymer component and the solubility with respect to the solvent better, and it can fully ensure In terms of the film strength of the liquid crystal alignment film, the molecular weight of the cyclic siloxane compound [A] is preferably less than 1000, more preferably 900 or less, further preferably 800 or less. Moreover, from the viewpoint of suppressing volatilization of the cyclic siloxane compound [A], the lower limit of the molecular weight is preferably 100 or more, more preferably 200 or more.

Specific examples of the cyclic siloxane compound [A] include compounds represented by the following formulas (A-1) to (A-10), respectively. In addition, you may use a commercial item as a cyclic siloxane compound [A]. Examples of commercially available items include: CS-697, CS-783 (the above are manufactured by Sigma-Aldrich), KR-470, X-40-2670, X-40-2678 (the above are Shinetsu Silicone Co., Ltd.) and the like.

[Chem 3]

[chemical 4]

(In formulas (A-1) to (A-7), R is a hydrogen atom or a methyl group, and n is an integer of 0 to 18)

From the viewpoint of sufficiently improving the effect of improving the light resistance and heat resistance of the obtained liquid crystal element, the content ratio of the cyclic siloxane compound [A] is preferably 20% to the polymer component contained in the liquid crystal alignment agent. A total amount of 100 parts by mass is 0.01 part by mass or more, more preferably 0.05 part by mass or more, still more preferably 0.1 part by mass or more. In addition, the upper limit of the content ratio of the cyclic siloxane compound [A] is preferably as high as that of the cyclic siloxane compound [A]. With respect to 100 mass parts of the total amount of the polymer component contained in a liquid crystal alignment agent, it is 40 mass parts or less, More preferably, it is 30 mass parts or less, More preferably, it is 20 mass parts or less. In addition, the cyclic siloxane compound [A] may be used individually by 1 type, and may use it in combination of 2 or more types.

<other ingredients>

The liquid crystal alignment agent disclosed herein may contain other compounds other than the polymer component and the cyclic siloxane compound [A] as needed. Specific examples thereof include epoxy compounds (for example, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidyl Aminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N-diglycidyl-aminomethyl cyclohexane, 1,6-hexanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, etc.), functional silane compounds (for example, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl)-3-aminopropyltrimethoxysilane, etc.), antioxidants, metal chelate compounds, hardening accelerators, surfactants, fillers, dispersants, photosensitizers, etc. The compounding ratio of other compounds can be suitably selected according to each compound in the range which does not impair the effect of this indication.

In addition, when a compound different from the cyclic siloxane compound [A] is used together as a crosslinking agent, the content ratio of the compound is relative to the total amount of the cyclic siloxane compound [A] contained in the liquid crystal alignment agent. The amount is preferably at most 5% by mass, more preferably at most 1% by mass.

<Solvent composition>

The liquid crystal alignment agent disclosed in the present disclosure is prepared in the form of a solution-like composition, and the solution The liquid composition is preferably obtained by dissolving a polymer component, a cyclic siloxane compound [A], and components arbitrarily prepared as needed in an organic solvent. Examples of the organic solvent include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. The solvent component may be one of these, or a mixed solvent of two or more.

Examples of the solvent component include: a solvent with high polymer solubility and leveling properties (hereinafter also referred to as "first solvent"), a solvent with good wetting and spreading properties (hereinafter also referred to as "second solvent") ), and these mixed solvents.

As specific examples of the solvent, the first solvent includes, for example: N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactamide, N,N-dimethylformamide, N, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, diisobutyl ketone, ethyl carbonate, propylene carbonate, N-ethyl-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, 1,3-dimethyl -2-imidazolidinone, 3-butoxy-N,N-dimethylacrylamide, 3-methoxyl-N,N-dimethylacrylamide, etc.; the second solvent is, for example, ethyl Glycol monobutyl ether (butyl cellosolve), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diacetone alcohol, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, Diethylene glycol methyl ethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, 3-methoxy-1-butanol, cyclopentanone, butyl lactate, butyl acetate, methyl methoxy Ethyl propionate, ethyl ethoxy propionate, isoamyl propionate, isoamyl isobutyrate, propylene glycol diacetate, dipropylene glycol monomethyl ether, propylene glycol monobutyl ether, diisoamyl ether, etc. . In addition, as a solvent, although one of these can be used independently, it is preferable to use it as the mixed solvent of a 1st solvent and a 2nd solvent.

The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) can be appropriately selected in consideration of viscosity, volatility, etc., preferably 1 mass %~10% by mass. When the solid content concentration is less than 1% by mass, the film thickness of the coating film is too small, and it is difficult to obtain a favorable liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by mass, the film thickness of the coating film is too large, making it difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent tends to increase, which tends to reduce applicability.

<<Liquid crystal alignment film and liquid crystal element>>

The liquid crystal alignment film disclosed herein is formed from the liquid crystal alignment agent prepared as described above. In addition, the liquid crystal element disclosed herein 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, it can be applied to twisted nematic (Twisted Nematic, TN) type, super twisted nematic (Super Twisted Nematic, STN) type, vertical alignment (Vertical Alignment, VA) type (including vertical alignment-multi-domain vertical alignment (Vertical Alignment-Multi-domain Vertical Alignment, VA-MVA) type, vertical alignment-pattern vertical alignment (Vertical Alignment-Patterned Vertical Alignment, VA-PVA) type, etc.), coplanar switching (In-Plane Switching, IPS) type, Fringe Field Switching (Fringe Field Switching, FFS) type, Optically Compensated Bend (Optically Compensated Bend, OCB) type, PSA type (Polymer Sustained Alignment) and other modes. A liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, the board used differs depending on the desired operation mode. Step 2 and Step 3 are common in all action modes.

<Step 1: Formation of coating film>

First, the liquid crystal alignment agent is coated on the substrate, preferably by heating the coated surface, thereby forming a coating film on the substrate. As the substrate, for example, a transparent substrate including glass such as float glass and soda glass; polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly( Alicyclic olefin) and other plastics. The transparent conductive film provided on one side of the substrate can be used: Nesser (NESA) film (registered trademark of U.S. PPG Corporation) containing tin oxide (SnO ₂ ), containing indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) indium tin oxide (Indium Tin Oxide, ITO) film, etc. In the case of manufacturing a TN-type, STN-type or VA-type liquid crystal element, two substrates provided with patterned transparent conductive films are used. On the other hand, when manufacturing an IPS type or an FFS type liquid crystal element, a substrate provided with electrodes patterned into a comb-shaped shape and a counter substrate provided with no electrodes are used. Coating the liquid crystal alignment agent on the substrate is preferably carried out on the electrode formation surface by lithographic printing, flexographic printing, spin coating, roll coater or inkjet printing.

After applying the liquid crystal alignment agent, for the purpose of preventing dripping of the applied liquid crystal alignment agent, etc., it is preferable to perform preheating (prebaking). The pre-baking temperature is preferably 30° C. to 200° C., and the pre-baking time is preferably 0.25 minutes to 10 minutes. Thereafter, a calcining (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 calcining temperature (post-baking temperature) at this time is preferably from 80°C to 250°C, more preferably from 80°C to 200°C. The post-baking time is preferably 5 minutes to 200 minutes. The film thickness of the film thus formed is preferably 0.001 μm to 1 μm.

<Step 2: Alignment Processing>

When manufacturing a TN type, STN type, IPS type or FFS type liquid crystal element, the process (alignment process) which provides liquid crystal alignment ability to the coating film formed in the said process 1 is implemented. Thereby, the alignment ability of a liquid crystal molecule is given to a coating film, and it becomes a liquid crystal alignment film. As the alignment treatment, the following treatment can be used: rubbing the coating film formed on the substrate in a certain direction with a roller wound with a cloth containing fibers such as nylon (nylon), rayon (rayon), cotton (cotton), etc. Rubbing treatment, photo-alignment treatment for imparting liquid crystal alignment ability to the coating film by irradiating light to the coating film formed on the substrate, and the like. On the other hand, in the case of manufacturing a vertical alignment (VA) liquid crystal element, the coating film formed in step 1 can be directly used as a liquid crystal alignment film, but in order to further improve the liquid crystal alignment ability, the coating film can also be Implement alignment processing. A liquid crystal alignment film suitable for a vertical alignment type liquid crystal element may also be suitable for a PSA type liquid crystal element.

In the photo-alignment process, the photoirradiation can be performed by the following methods: 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 method of irradiating the coating film during heating of the coating film in at least any one of the pre-baking step and the post-baking step. As the radiation irradiated to the coating film, for example, ultraviolet rays and visible rays including light having a wavelength of 150 nm to 800 nm can be used. Ultraviolet rays including light having a wavelength of 200 nm to 400 nm are preferable. When the radiation is polarized light, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, 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 of these directions. In the case of non-polarized radiation, the irradiation direction is set to Tilt direction.

Examples of the light source used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, and excimer lasers. The radiation dose to the substrate surface is preferably from 400J/m ² to 50,000J/m ² , more preferably from 1,000J/m ² to 20,000J/m ² . After being irradiated with light for imparting alignment ability, it is also possible to use such as water, organic solvents (for example, methanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, etc.) on the surface of the substrate. Ethyl lactate, etc.) or a mixture of these is cleaned, or the substrate is heated.

<Step 3: Construction of the liquid crystal cell>

The two substrates on which the liquid crystal alignment film was formed as described above were prepared, and the liquid crystal cell was manufactured so that the liquid crystal was arranged between the two substrates adjacent to the liquid crystal alignment film. When manufacturing a liquid crystal cell, for example, the following method can be cited: two substrates are arranged to face each other through a gap in such a way that the liquid crystal alignment film faces each other, and the peripheral parts of the two substrates are bonded together by a sealant, and the surface of the substrate is bonded to the sealant. A method of injecting liquid crystal into the enclosed cell gap and sealing the injection hole, a method of using a liquid crystal drop filling (One Drop Fill, ODF) method, and the like. As the sealing agent, for example, an epoxy resin containing a curing agent and alumina balls as spacers can be used. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals, among which nematic liquid crystals are preferred. In the PSA mode, after constructing a liquid crystal cell, light irradiation processing is performed on the liquid crystal cell in a state where a voltage is applied between conductive films included in a pair of substrates.

When producing a PSA-type liquid crystal element, a liquid crystal cell is constructed in the same manner as above except that a liquid crystal is injected or dropped between a pair of substrates having a conductive film together with a photopolymerizable monomer. In addition, a previously known compound can be used for a photopolymerizable monomer. A polyfunctional (meth)acrylic monomer is preferable. Thereafter, the liquid crystal cell is irradiated with light in a state where a voltage is applied between the conductive films included in the pair of substrates. The voltage applied here can be, for example, a direct current or an alternating current of 5V to 50V. In addition, as light to be irradiated, for example, ultraviolet rays and visible rays including light having a wavelength of 150 nm to 800 nm can be used. Among these, ultraviolet rays including light having a wavelength of 300 nm to 400 nm are preferable. As a light source for irradiating 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 irradiation amount of light is preferably 1,000 J/m ² to 200,000 J/m ² , more preferably 1,000 J/m ² to 100,000 J/m ² .

Then, if necessary, a polarizing plate is bonded to the outer surface of the liquid crystal cell to prepare a liquid crystal cell. Examples of polarizing plates include polarizing films called "H films" in which polyvinyl alcohol is stretched and aligned on one side and iodine is absorbed on the other, between cellulose acetate protective films, or polarizing plates that include the H film itself. polarizer.

The disclosed liquid crystal element can be effectively applied to various purposes, for example, it can be applied to clocks, portable game machines, word processors, notebook personal computers, car navigation systems, camcorders, personal digital assistants (Personal Digital Assistant, PDA) ), digital cameras, mobile phones, smart phones, various monitors, LCD TVs, information displays and other display devices, or dimming films, phase difference films, etc.

[Example]

Hereinafter, although an Example demonstrates concretely, this invention is not limited to the following Example.

In the following examples, the solution viscosity, weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw/Mn) and epoxy equivalent of the polymer are measured by the following methods.

<Solution viscosity of polymer>

The solution viscosity of the polymer is measured at 25° C. using an E-type viscometer.

<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. The molecular weight distribution (Mw/Mn) was calculated from the obtained Mw and Mn.

Device: "GPC-101" by Showa Denko Co., Ltd.

GPC column: connect "GPC-KF-801", "GPC-KF-802", "GPC-KF-803" and "GPC-KF-804" manufactured by Shimadzu GLC (SHIMADZU GLC)

Mobile phase: tetrahydrofuran (tetrahydrofuran, THF)

Column temperature: 40°C

Flow rate: 1.0mL/min

Sample concentration: 1.0% by mass

Sample injection volume: 100μL

Detector: Differential refractometer

Standard material: monodisperse polystyrene

<Epoxy equivalent>

The epoxy equivalent is measured by the hydrochloric acid-methyl ethyl ketone method described in Japanese Industrial Standards (JIS) C 2105.

Abbreviations of compounds used in the following examples are shown below. In addition, "the compound represented by formula (X)" may be simply expressed as "compound (X)" for convenience below.

． Cyclic siloxane compound[A]

． Other than cyclic siloxane compound [A]

[chemical 6]

<Synthesis of Polymer>

[Synthesis Example 2-1: Synthesis of Polyimide]

77 g (0.34 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride, 19 g (0.18 mol) of p-phenylenediamine as diamine and 3,5-diamine Aminobenzoic acid 27g (0.18 mol) was dissolved in N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, NMP) 1,260g, and reacted at room temperature for 6 hours, thereby obtaining poly Amino acid solution. A small amount of the obtained polyamic acid solution was collected and concentrated under reduced pressure to obtain a solution with a concentration of 10% by mass. The measured solution viscosity was 80 mPa. s. Next, 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. After the dehydration and ring-closure reaction, the solvent in the system was replaced with new γ-butyrolactone, and then concentrated to obtain 20 mass % as a solution of 600 g of a polyimide polymer (PI-1) with an imidization rate of about 85%. A small amount of this solution was divided, and γ-butyrolactone was added to prepare a solution with a concentration of 6.0% by mass. The measured solution viscosity was 22 mPa. s.

[Synthesis Example 2-2: Synthesis of Polyamic Acid]

13.8 g (0.070 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride, 2,2'-dimethyl-4,4'-diamine as diamine 16.3 g (0.0769 mol) of aminobiphenyl was dissolved in 170 g of NMP, and reacted at 25°C for 3 hours to obtain a polyamic acid containing 10% by mass (referred to as "polymer (PA-1) ")The solution.

[Synthesis Example 2-3: Synthesis of Styrene-Maleimide Copolymer]

Under nitrogen, 5.00 g (8.6 mmol) of compound (MI-1), 0.64 g (4.3 mmol) of 4-vinylbenzoic acid, 4-(2,5-di Oxygen-3-pyrroline-1-yl)benzoic acid 2.82g (13.0mmol), and 4-(glycidyloxymethyl)styrene 3.29g (17.2mmol), as a radical polymerization initiator 2 , 0.31g (1.3mmol) of 2'-azobis (2,4-dimethylvaleronitrile), 0.52g of 2,4-diphenyl-4-methyl-1-pentene as a chain transfer agent ( 2.2 mmol) and 25 ml of tetrahydrofuran as a solvent were polymerized at 70° C. for 5 hours. After reprecipitation in n-hexane, the precipitate was filtered and vacuum-dried at room temperature for 8 hours to obtain a polymer (StMI-A) which was a styrene-maleimide copolymer. The weight average molecular weight Mw measured by the polystyrene conversion by GPC was 30000, and the molecular weight distribution Mw/Mn was 2.

[Synthesis Example 2-4: Synthesis of Styrene-Maleimide Copolymer]

In Synthesis Example 2-3, Compound (MI-2) was used instead of Compound (MI-1) Polymerization was carried out in the same manner as in Synthesis Example 2-3 except for polymerizing monomers. After reprecipitation in n-hexane, 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 the polystyrene conversion by GPC was 25000, and the molecular weight distribution Mw/Mn was 2.

[Synthesis Example 2-5: Synthesis of Epoxy Group-Containing Polyorganosiloxane]

Put 100.0 g of 2-(3,4-epoxycyclohexyl) ethyl trimethoxysilane, 500 g of methyl isobutyl ketone and triethyl 10.0 g of the amine was mixed at room temperature. After adding 100 g of deionized water dropwise from the dropping funnel over 30 minutes, the mixture was mixed under reflux and reacted at 80° C. for 6 hours. After the reaction, the organic layer was taken out, washed with 0.2% by mass of ammonium nitrate aqueous solution until the washed water became neutral, and then the solvent and water were distilled off under reduced pressure, thereby obtaining a viscous transparent liquid Form of epoxy-containing polyorganosiloxane. When the epoxy equivalent of this epoxy group-containing polyorganosiloxane (let it be "polyorganosiloxane (PS-1)") was measured, it was 186 g/equivalent.

<Preparation and Evaluation of Liquid Crystal Alignment Agent>

[Example 1]

1. Preparation of liquid crystal alignment agent (AL-1)

10 parts by mass of the polymer (StMI-A) obtained in the synthesis example 2-3, compound (A-1-1) (trade name "KR-470", manufactured by Shinetsu Silicone Co., Ltd.) 2 parts by mass, and NMP and butyl cellosolve as a solvent (butyl cellosolve, BC) to prepare a solution with a solvent composition of NMP/BC=50/50 (mass ratio) and a solid content concentration of 4.0% by mass. The liquid crystal alignment agent (AL-1) was prepared by filtering the solution through a filter with a pore diameter of 1 μm.

2. Fabrication of Photovertical Liquid Crystal Cells

The prepared liquid crystal alignment agent (AL-1) was coated on the transparent electrode surface of the glass substrate with the transparent electrode including the ITO film using a spinner, and pre-baked for 1 minute by using a heating plate at 80°C. Then, it heated at 230 degreeC for 1 hour in the oven which substituted nitrogen gas in the cavity, and formed the coating film with a film thickness of 0.1 micrometer. Next, using a Hg-Xe lamp and a Glan-Taylor prism, the surface of the coating film was irradiated with 1,000 J/m of polarized ultraviolet rays including a bright line of 313 nm from a direction inclined 40° from ^the normal line of the substrate to obtain Give liquid crystal alignment ability. The same operation was repeated to prepare a pair (two) of substrates with a liquid crystal alignment film.

On the outer periphery of the surface with the liquid crystal alignment film of one of the pair of substrates, after coating the epoxy resin adhesive with alumina balls with a diameter of 3.5 μm by screen printing, the pair of substrates The surfaces of the liquid crystal alignment films faced each other, and pressure bonding was performed so that the optical axis of ultraviolet light of each substrate was antiparallel to the projection direction of the substrate surface, and the adhesive was thermoset at 150° C. for 1 hour. Next, after filling the gap between the substrates from the liquid crystal injection port with a negative type liquid crystal (MLC-6608 manufactured by Merck), the liquid crystal injection port was sealed with an epoxy-based adhesive. Furthermore, in order to remove the flow alignment at the time of liquid crystal injection, this was heated at 130 degreeC, and it cooled gradually to room temperature, and the liquid crystal cell was obtained. Then, on both sides of the outer side of the substrate, the polarization directions of the polarizers are perpendicular to each other and are in the same direction as the projection direction of the optical axis of the ultraviolet rays of the liquid crystal alignment film on the substrate surface. The polarizing plate is bonded at an angle of 45° to manufacture a light-vertical liquid crystal display element.

3. Evaluation of liquid crystal display elements

These operations were repeated to manufacture a plurality of liquid crystal display elements, and the following heat resistance and light resistance evaluations were performed. In addition, the evaluation of heat resistance and light resistance was performed using a different liquid crystal display element, respectively.

[Evaluation of heat resistance]

After applying a voltage of 5 V at 60° C. for an application time of 60 microseconds and a span of 167 milliseconds to the liquid crystal display element manufactured above, the voltage retention rate after 167 milliseconds from the release of the application was measured, and This is set as the initial voltage retention rate Arf [%]. Next, the liquid crystal cell was left still in an oven at 100° C. for 1,000 hours to apply thermal stress, and then the voltage retention was measured again under the same conditions, and this was defined as voltage retention Atm [%] after thermal stress. The decrease amount α [%] (α=Arf-Atm) of the voltage retention rate Atm after thermal stress relative to the initial voltage retention rate Arf was calculated, and the heat resistance of the liquid crystal display element was evaluated based on the decrease amount α. When the amount of decrease α was 1% or less, the heat resistance was evaluated as "extremely good (◎)", and when the amount of decrease α was more than 1% and 2% or less, the heat resistance was evaluated as "good (○)". When the amount α was more than 2% and 3% or less, the heat resistance was evaluated as “OK (△)”, and when the decrease amount α was more than 3%, the heat resistance was evaluated as “Poor (×)”. As a result, in this Example, the heat resistance was evaluated as "extremely good (⊚)". In addition, the measuring apparatus of the voltage retention rate used the VHR-1 manufactured by TOYO Technica (KK).

[Evaluation of light resistance]

For the liquid crystal display element manufactured above, in the same conditions as the evaluation of heat resistance The voltage retention rate was measured under the conditions, and it was set as the initial voltage retention rate Arf [%]. Next, the liquid crystal display element was placed at a distance of 5 cm under a 0-watt white fluorescent lamp, and after irradiating light for 1,000 hours to impart light stress, the voltage retention rate was measured again under the same conditions, and this was set as the light stress Post-voltage retention rate Agt[%]. Calculate the reduction amount β [%] (β=Arf-Agt) of the voltage retention rate Agt relative to the initial voltage retention ratio Arf after light stress, and evaluate the light resistance of the liquid crystal display element according to the reduction amount β. When the reduction amount β is 1% or less, the light resistance is evaluated as "extremely good (◎)", and when the reduction amount β is more than 1% and 2% or less, the light resistance is evaluated as "good (○)". When the amount β was more than 2% and 3% or less, the light resistance was evaluated as "acceptable (Δ)", and when the decrease amount β exceeded 3%, the light resistance was evaluated as "poor (×)". As a result, in this Example, the light resistance was evaluated as "extremely good (⊚)".

[Example 2～Example 9 and Comparative Example 1, Comparative Example 2, Comparative Example 4, Comparative Example 6]

Except for changing the compounding composition as shown in the following Tables 1 to 3, preparation was carried out with the same solvent composition and solid content concentration as in Example 1, and liquid crystal alignment agents were respectively obtained. In addition, an optical vertical type liquid crystal display element was produced in the same manner as in Example 1 using each liquid crystal alignment agent, and various evaluations were performed. These results are shown in Tables 1 to 3 below.

[Example 10]

1. Preparation of liquid crystal alignment agent (AL-10)

Except that the polymer used was changed to the solution containing 100 parts by mass of the polymer (PA-1) obtained in the above-mentioned Synthesis Example 2-2, and the solution obtained in the above-mentioned Synthesis Example 2-4 A liquid crystal alignment agent (AL-10) was prepared with the same solvent composition and solid content concentration as in Example 1 except for 5 parts by mass of the polymer (StMI-B).

2. Preparation of liquid crystal composition

5% by mass of the liquid crystal compound represented by the formula (L1-1) and 0.3% by mass of the liquid crystal compound represented by the formula (L2- 1) The photopolymerizable compound shown in 1) was mixed, and liquid crystal composition LC1 was obtained by this.

3. Manufacture of PSA type liquid crystal display element

Use a liquid crystal alignment film printer (manufactured by Nippon Photo Printing Co., Ltd.) to coat the prepared liquid crystal alignment agent (AL-10) on each electrode surface of two glass substrates with conductive films comprising ITO electrodes, After removing the solvent by heating (pre-baking) on a hot plate at 80° C. for 2 minutes, it heated (post-baked) on a hot plate at 230° C. for 10 minutes to form a coating film with an average film thickness of 0.06 μm. These coating films were cleaned by ultrasonic waves for 1 minute in ultrapure water, and then dried in a clean oven at 100° C. for 10 minutes to obtain a pair (two sheets) of substrates with liquid crystal alignment films. In addition, the pattern of the electrode used is the same kind of pattern as the electrode pattern in PSA mode.

Then, on the outer edge of the surface with the liquid crystal alignment film of one of the pair of substrates, after coating the epoxy resin adhesive with alumina balls with a diameter of 5.5 μm, the surface of the liquid crystal alignment film faces each other. Overlap and crimp to harden the adhesive. Next, after filling the prepared liquid crystal composition LC1 between the pair of substrates from the liquid crystal injection port, the liquid crystal injection port was sealed with an acrylic light-curing adhesive, thereby manufacturing a liquid crystal cell. Thereafter, AC 10V at a frequency of 60 Hz was applied between the conductive films of the liquid crystal cell to drive the liquid crystal, and ultraviolet rays were irradiated at an irradiation dose of 100,000 J/m ² using an ultraviolet irradiation device using a metal halide lamp as a light source. In addition, this irradiation amount is the value measured using the light meter which measures based on wavelength 365nm. Afterwards, on both sides of the outer side of the substrate, polarizing plates are bonded in such a way that the polarization directions of the polarizing plates are perpendicular to each other and form an angle of 45° with the projection direction of the ultraviolet light of the liquid crystal alignment film on the substrate surface, thereby manufacturing a PSA type Liquid crystal display element.

4. Evaluation of liquid crystal display elements

These operations were repeated to manufacture a plurality of liquid crystal display elements, and were evaluated in the same manner as in Example 1 for heat resistance and light resistance. As a result, in this Example, both heat resistance and light resistance were evaluated as "extremely good (⊚)".

[Example 11-Example 13 and Comparative Example 3-Comparative Example 5]

Except for changing the compounding composition as shown in the following Table 2 and Table 3, preparation was carried out with the same solvent composition and solid content concentration as in Example 10, and liquid crystal alignment agents were respectively obtained. In addition, a PSA type liquid crystal display element was manufactured in the same manner as in Example 10 using each liquid crystal alignment agent, and various evaluations were performed in the same manner as in Example 1. These results are shown in Table 2 and Table 3 below.

[Table 1]

[table 3]

In Tables 1 to 3, "-" indicates that the compound in the column was not used. The abbreviations of the compounds are as follows.

A-1-1: Trade name "KR-470", manufactured by Shinetsu Silicone Co., Ltd. (the compound represented by the above formula (A-1-1))

A-2-1: Trade name "CS-697", manufactured by Sigma-Aldrich (compound represented by the above formula (A-2-1))

A-3-1: Trade name "CS-783", manufactured by Sigma-Aldrich (compound represented by the above formula (A-3-1))

C-1: Trade name "X-40-2669", manufactured by Shinetsu Silicone Co., Ltd. (the compound represented by the above formula (C-1))

C-2: the polyorganosiloxane (PS-1) of the synthesis example 2-5

C-3: N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane (the Compound represented by formula (C-3))

Based on the above results, in Examples 1 to 13 using the liquid crystal alignment agent containing the cyclic siloxane compound [A] as a crosslinking agent, the evaluation of the heat resistance and light resistance of the liquid crystal display element was "extremely good ( ◎)” or “Good (○)” results.

On the other hand, in Comparative Example 4 and Comparative Example 5 in which the composition of the liquid crystal alignment agent was the same except that the cyclic siloxane compound [A] was not contained, both the light resistance and the heat resistance were inferior to those of the Examples. .

In addition, in Comparative Example 1 in which the compound (C-1) which is a polyfunctional siloxane compound having a chain structure was used instead of the cyclic siloxane compound [A], compared with Examples (Example 1 to Example 3) In comparison, light resistance was inferior, and compared with Example 1 and Example 2, heat resistance was also inferior. In Comparative Example 2 and Comparative Example 3 in which polyorganosiloxane (PS-1) was used instead of the cyclic siloxane compound [A], compared with Examples (Example 1 to Example 3, Example 10 to Example 13) In comparison, both light resistance and heat resistance are inferior.

Moreover, about the comparative example 6 which used the compound (C-3) used conventionally as a crosslinking agent, both light resistance and heat resistance were inferior compared with an Example.

From these results, it was found that a liquid crystal element excellent in heat resistance and light resistance can be obtained by using the cyclic siloxane compound [A] as a crosslinking agent.

Claims (9)

A liquid crystal alignment agent, which contains: a polymer component; and a cyclic siloxane compound [A] having a crosslinkable group, wherein the crosslinkable group includes an oxirane group, an oxycyclobutyl group , (meth)acryl, allyl, vinylphenyl, cyclic carbonate, methylol or one or more of amine. The liquid crystal alignment agent described in item 1 of the scope of the patent application, wherein the cyclic siloxane compound [A] is a compound represented by the following formula (1),

(In formula (1), R ¹ ~ R ⁶ are independently hydrogen atoms or monovalent organic groups with 1 ~ 20 carbons; wherein, at least one of R ¹ ~ R ⁶ is a crosslinkable group with the Monovalent organic group; n is an integer of 1 to 18; when n is 2 or more, multiple R ¹ may be the same or different from each other, and multiple R ² may be the same or different from each other). The liquid crystal alignment agent as described in item 1 or item 2 of the scope of patent application, wherein the polymer component is selected from polyamic acid, polyamic acid ester, polyimide, and At least one of the group consisting of polymers of structural units of monomers having unsaturated bonds. The liquid crystal alignment agent as described in item 1 or item 2 of the patent claims, which contains two or more polymers as the polymer components. The liquid crystal alignment agent described in claim 3 of the patent application contains two or more polymers as the polymer components. A liquid crystal alignment film, which is formed by using the liquid crystal alignment agent described in any one of items 1 to 5 in the scope of the patent application. A liquid crystal element, which includes the liquid crystal alignment film described in item 6 of the scope of application. A method of manufacturing a liquid crystal element, which includes: applying the liquid crystal alignment agent described in any one of the first to fifth items of the scope of the patent application on each of a pair of substrates, and irradiating light, thereby forming a liquid crystal an alignment film step; and a step of constructing a liquid crystal cell by arranging the pair of substrates on which the liquid crystal alignment film is formed so that the liquid crystal alignment films face each other with a liquid crystal layer interposed therebetween. A method for manufacturing a liquid crystal element, which includes: coating the liquid crystal alignment agent described in any one of the first to fifth items of the scope of the patent application on the respective conductive films of a pair of substrates with conductive films And the step of forming coating film; The step of constructing a liquid crystal cell by arranging the pair of substrates coated with the liquid crystal alignment agent with the liquid crystal layer facing each other so that the coating films face each other; and applying a voltage to the conductive film The liquid crystal cell is subjected to a step of light irradiation.